Evolution: The First Four Billion Years

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with essayson the social and political sienificance of evolutionary biology today. A second, encyclopedic section travels the spectrum of topics in evolution with concise, informative, and accessibleentries on individuals from Aristotle and Linnaeus to Louis Leakey and Jean Lamarck; from T. H. Huxley and Edward O. Wilson to Joseph Felsenstein and Motoo Kimura; and on subjects fronr altruism and an-rphibiansto evolutionary psychology and Piltdown Man to the Scopestrial and social Darwinism. Readers will find the latest word on the history and philosophy of evolution, the nuancesof the scienceitself, and the intricate interplay anong evolutionary study,religion, philosophy, and sociery. Appearing at the beginning of the Darwin Year of 2oo9-the

zooth anniversary of the

birth of Charles Darwin and the rjoth anniversary of the publication of the Origirt o-f Species-this volume is a fitting tribute to the s c i e n c eD a r w i n s e t i n n l o t i o n .

M TcHAEL

RUSE

i s L u c y l eT . W e r k n r e i s t e r

Professor of Philosophy and Director of the Progranr in the History and Philosophy of Science, Florida State (Jniversiry.He is the founder and ediBiologyand Philosophyand has ap-

tor ofthejournal

peared on "Quirks and Quarks" and the Discovery Channel. His books include Tlrc Euolution-Crcdtiort Struggleand Danyin and Desigtrftoth from Harvard). J oS EPH

T R A V T S i s D e a n o f t h e C o l l e g eo f

Arts and Sciencesand Robert O. Lawton Distinguished Professor of Biological Science at Florida State Universiry.

The BelknapPressof HarvardUniversiryPress Cambridge,Nlassathusetts, attd Lturdon,England

www.hup.harvard. edu

Jacket illustration: DEA

Picturr Librarv/(letn

Jacket design: Jill Breitbarth

Inrrqes

"One of the first and likely to be the most comprehensive in scope of the many books occasionedby the zoog sesquicentennialofDarwin's Origin." -Edward

FROM

THE

O.Wilson

EDITORS'

INTRODUCTION

This book presentsevolutionary science as a modern, dynamic discipline and allows the reader to explore evolution according to his or her interestsand background. The reader who wishes to be immersed in the science can focus on the major scientific themes, while the reader who is interested in the intellectual history and influence of the subject away from science can enter through a separateset of essays. A reader interested in very specific topics or historical figures can find the appropriate entries, along with essayson related topics. Our goal was to provide an exciting and compelling introduction to evolution along with a basic reference work that could point the way toward a deeper study of individual issues. The essaysinclude bibliographies, which serve as guides to further and deeper reading.The essaysin this book show not only how far we have come but where the scientific horizons lie and how we might move toward those horizons.

rsBN378-0-b7rr-03175-3

90000

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ЕVoLUTloN The First Four Billion Yeаrs

EDlтЕD BY

MlсHAЕL RUsE JosЕPH TRAVls W|тH A FoRЕWoRD BY

ЕDWARD o. WlLsoN

т H E в E L K N A PP R Е s s o F н A R V A R DU N l V Е R s | т YP R Е s s с A t ' 4 B R I D GМ ЕA . ssAсHUsЕттs L o N D o N ,Е N G L A N D 2009

Сontеnts

Сopyright o 2009 by thе Prеsidеntand Fеllows of Нarvаrd Collеgе All rights rеsеrvеd Printеd ir-rthе Unitеd Stаtеs Of Amеriс:r Librаrу of Сoпgrеss Саtаlogiпg-iп-Publiсаtion Dаtа Еvоlution : thе first fсlur Ьillion yеars / еditеd by Мiсhaеl Rusе, Josеph Trаvis ; with a forеword Ьу Еdwаrd O. Wilson. p. сm. InсludеsЬiЬliogгаphiсalrеfеrеnсesand indеx' I S B N 9 7 8 . 0 - 6 74 - 0 3 | 7 5 . з ( a l k . p a p е r ) 1. Еvolution (Biotogy) I. Rusе, Мiсhaеl. II. Travis,Josеph, 1953QH366.2.Е86з zО09

576.8-dс22

2008030270

Fоrеword Еdшаrd О.Wils,

Introduсtion NIiсhаеl Ruse аl

Thе Histoгy of Еvolu Мiсhаеl Rцsе

Thе origin of Lifе Jеffrеу L' Bаdа c

Palеontolоgy and thе МiсhаеI Bеnton

Adaptation Josеph Trаuis аt Мolесulаr Еvolutiоn FrаnсisсoJ.Aуа

Еvolution of thе Gеnr Briаn Сhаrlesш

Thе Pattеrn and Proс Маrgаrеt B. Ptа,

Еvolution and Dеvеlо Grеgorу A. IVrа

Soсial Bеhavior and S Dапiеl I. Rubеп Human Еvolution Hеnrу М. МсH

ЕvotutionагyBiоlogy Мiсhаеl F' Аnto

Contеnts

nd Fеllows of Hаrvard Сoliеgе sеrvеd 'tаtеsof Amеriсa ,пg-iп- Pub liсаtklп D аtа геd by Miсhаеl Rusе, Josеph Travis ; ward O. Wilson. эfеrеnсеsand iгrdех. '5-3 (alk. paреr) haеl. II. Travis,Josеph' 1953-

3 2009 20080зО270

Foгеword Еdшаrd O' Wilson Introduсtion Мiсhаеl Rusе апd Josеph Trаuis

UTl

iх

Thе History of Еvolutiоnary Thought Мiсhаеl Rиsе Thе origin of Lifе JеffreуL. Bаdа аnd Aпtonio Lаzсаno

49

Palеontologyand thе History of Lifе Мiсh,lеl Bепtoп

80

Adaptatiоn Josеph Тrаuis аnd Dаuid N. Rеzпiсk

105

МolесulaгЕvolution Frаnсisсol. Ауаlа

1З2

Еvоlution оf thе Gеnomе Briап Сbаrlеstuorthаnd Dеborаh Сhаrlеsшorth

152

Thе Pattеrn and Proсеssof Spесiation Маrgаrеt B, Ptасеk аnd Sbаlа l. Наnktsoп

177

Еvolution and Dеvеlopmеnt Crеgorу A' Wrау

208

Soсial Bеhaviоr and Soсiоbiolоgy DаnielI,Rиbеnstein

2З7

Human Еvolution Неnrу М. МсНеnrу

256

ЕvolutionaryBiolоgy of Disеasеand Darwinian Меdiсinе МiсhаеlF. Anto|ш

281

Contепts Bеyond thе Darwinian Paradigm:UndеrstandingBiolоgiсal Foгms Briаn Goodtuiп

299

Philosоphy of Еvolutionary ThougЬt Kim Stеrеlпу

31З

Еvolution and Soсiеty Мапfrеd D. Lаubiсblеr апd Jапе Маiепsсhеin

ЗЗ0

Forеwor

Еvolution and Rеligion Dаuid N' Liuiпgstonе

З48

ЕdшаrdО

Amегiсan Antiеvolutionism: Rсtrospесt and Prospесt ЕugепiеС. Sсott

З70

Alphabеtiсal Guidе

401

сontriЬЦtors

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IllustrationСrеdits

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Indех

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Two сеnturiеs aftеr i Сharlеs Darwin's ozz important Ьook еvеr. tЬe Оrigiп havе not t arе not prеaсhеd frоп oath of offiсе with a drеssеd thе living wol ity's plaсе within it, v massivе sсiеntifiс еvid havе grown сontinuo undеrstanding and tht So solidly havе thе of еvolution that it ml (univеrsal prinсiplеs i: first law is that all thе ultimatеly obеdiеnt tс has Ьееn thе driving f half сеntury. Thе sес Ьiology as wеll as mu( еlеmеnts and proсеss еvolution through nat Тhе two laws havе 1 for thе rесognition of grее thеy arе bеing сo logiсal phеnomеna. T thе sесondaddrеssеs еxamplе, arе built and not somе othеr. Еaсh lvIodеrn biology as a l proaсhеs guidеd Ьy th Еvеn without thе iп samе as thе Darwin Ьil

еrstanding BiologiсaIForms

299

З1З

Маiепsсhеiп

сt аnd Pгospесt

ЗЗ0

Forеword

З48

ЕdьuаrdО. Wilson

З70 401 935 949 951

Two сеnturiеs aftеr its author's Ьirгh and 150 yеars aftеr its puЬliс:rtion, Сhаrlеs Darwin's Оп the Оrigin of Speсiеs сan fairly Ье rаnkеd as thе most important book еvеr writtеn. Not thе most widеly rеad, to Ье surе. Сopiеs of thе origiп havе not bееn plaсеd in hotеl rooms aсross Amеriсa; its vеritiеs arе not prеaсhеdfrom pulpits еaсlr Sunday; and no politiсal lеadеr takеs an oath of offiсе with a hаnd on its сovеr. It is thе mastеrрiесе that first ad. drеssеdthе living world and (with Тhe Descеnt of Мап following) humanityЪ plасе within it, without rеfеrеnсеto any rеligion or idеology and upon massivеsсiеntifiс еvidеnсе providеd aсross suссеssivе dесаdеs. Its argumеnts havе grown сontinuously in еstееm as thе Ьеst foundation for hцпran sеlfundеrstаndingand thе pЬilosophiсal guidе for human асrion. So solidly havе thе fiеlds of Ьiology Ьuilt upоn thе Darwinian сonсеption of еvolution that it makеs sеnsе tоday to rесognizе it as onе of thе two laws (univегsalprinсiplеs if you wish) that govеrn ouг undеrstanding of lifе. Thе firsг law is that all thе еlеmеnts and proсеssеs thаt dеfinе living organisms arе ultimatеly oЬеdiеnt to thе laws of physiсs and сhеmistry. This formulation has bееn thе dгiving forсе of molесular and сеllular Ьiology during thе past half сеntury' Thе sесoпd law, thе foundation :rnd produсt of еvolutionary Ьiology as wеll аs muсh of organismiс and еnvironmеntal Ьiology, is that all еlеmеnts and proсеssеs dеfining living organisms havе Ьееn gеnеratеd Ьy еvolutionthrоugh natural sеlесtiсln. Thе two laws havе provеn to Ье frrlly сomplеmеntary, a primе rеquirеmеnr for thе rесognition of sсiеntifiс laws gеnеrally. Furthеr' to an inсrеasing dеgrееthеy arе Ьеing сomЬinеd to aсhiеvе sеamlеssanalysеs of partiсular Ьiоlogiсal phеnomеna. Thе first law addгеssеs how a phеnonrеnon oссurs and thе sесond addrеssеswhy it oссurs. Mitoсhondria and othеr organеllеs, for еxamplе, arе built and work thus and so; and thеy originatеd in onе way and not somе othеr. Еaсh dеsсription сomplеtеs thе еxplanation for thе othеr. Мodеrn biology as a wholе has littlе mеaning without thе joining of both approaсhеs guidеd Ьy thе two lаws. Еvеn without thе impеtus of thе origin sеsquiсеntеnnial-fortuitously thе samеas thе Dаrwin Ьirth Ьiсеntеnniаl-2009 is an аppropriаtе timе to prеsеnt uп

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Foreшord еvolutionary Ьiology in its еnсompassing modеrn form. I douЬt that any singlе writеr, or any еnsеmЬlе of sеveral writеrs, сould summarizе this Ьurgеoning disсiplinе in a сomprеhеnsivе and authoritativе form. Thе multipliсity of authors in Еuolutioп: The First Foиr Billioп Yeаrs has gonе far to*ard that goal. Its array of ехpеrts providе statе of thе art for еaсh suЬjесt in turn. Thе sсiеnсе is prеsеntеd hеrе' Ьut also somе of thе main praсtiсal сonsеquеnсеs and in. еvitably, with fundamеntal rеlеvanсе, thе сonsеquеnсеs of Ьiologiсal еvolutionary thought for philosophy and rеligion. Thе grеat quеstions-..Who arе wе?'' ...Whеrеdid wе сomе from?'' and ...Whyarе wе hgrg}''-gan Ье аnswеrеd only, if еvеr, in thе light of sсiеntifiсally Ьasеd еvolutionary thought.

Introduс

NIiсhаеlR

Тhе disсovеry of еvolr .W.еstеrn thought, ranl аmong sсiеntifiс disс< From sееing naturе aI forеvеr сhanging, wе dеrstanding еvolution In sсiеnсе thе word idеas. First, thеrе is tl ganisms, living and dt natural proсеss of сh othеr, diffеrеnt onеs. l of thе anсiеtlt Grееks. ganisms еvolvеd rеally sidеrеd a Ьasiс elеmе puЬlishеd Ьis on tbe organisms on thе plar that opеratеd rеlеntlеs thе natцral world. An tology to moleсular Ьi еvidеnсе that еvolutiol Sесond, еuolution is gloЬе. This сan rеfеr t еvolution of orсhids, suсh as thе еvolution < reptilе iaw. Еvolution: еvidеnсе that rangеs fi to similaritiеs and diff tiоn of somе fеaturеs. stood, whilе thе еvolu organеllеs of сеlls, is lс Тhе third idеa is th that еvolution has not <

ldеrn form. I douЬt that any singlе сould summaгizеthis Ьurgеoning tivе form. Thе multipliсity of au,аrs has gonе far toward that goal. lr еaсh suЬjесtin turn. Thе sсiеnсе in praсtiсal сonsеquеnсеsand in:onsеquеnсеsof Ьiologiсal еvolu. Thе grеat quеstions-cGWho arе Y arewe hеге?''_сan Ье answеrеd d еvolutionarythought.

Introduсtion Мiсhаеl Rиse апd JosеphTrаuis

Thе disсovеry of evolution is onе of thе grеatеst intеllесtual aсhiеvеmеnts of .Wеstеrn thought, rаnking with thе сalсulus and gеnеrаl and spесifiс rеlativity among sсiеntifiс disсovеriеs that сhangеd indеliЬly how wе sее our world. From sееing naturе as fiхеd torеvеr in form and сomposition to sееing it as forеvеr сhanging, wе havе Ьееn transformеd uttеrly Ьy disсovеring and undеrstanding еvolution. In sсiеnсе thе word euolцtion is usеd to ехprеss thrее diffеrеnt Ьut rеlatеd idеаs. Fiгst, thеrе is rЬe fасt of еvolution. This is thе rеalization that all organisms, living and dеad' irrсluding humans, arе thе еnd produсts of a long natural proсеss of сhangе through whiсh еaсh spесiеs is dеsсеndеd from othеr, diffеrеnt onеs. Although protoеvolutionary idеas datе Ьaсk to the timе of thе аnсiеnt Grееks, only in thе еightееnth сеntury did thе сlaim that organisms еvolvеd rеally start to gain сurrеnсy. Howеvеr' thе idеa was not сonsidеred a Ьasiс еlеmеnt of sсiеntifiс knowlеdgе until aftеr Сharlеs Darwin puЬlishеd his ozl the Оrigiп of Spесiеs in 1859. Darwin arguеd that all thе organisms on thе planеt еmеrgеd through a singlе, straightforward proсеss that opеratеd rеlеntlеssly from thе dawn of lifе and that сontinuеs to shapе thе natural world. An еnormous amount of sсiеntifiсrеsеarсh,from palеontology to molесular biology' has providеd thе сompеlling and ovеrwhеlming еvidеnсеthat еvolution is indееd a faсt. Sесond, еuolиtion is oftеn usеd to rеfеr to the pаth of lifе's history on this gloЬе.This сan refег to thе history of a group of ехisting spесiеs,as in thе еvolutiоn of orсhids' or thе path through whiсh partiсular traits еmеrgеd, suсh as thе еvolution of thе middlе еar of mammals from small Ьonеs in thе геptilе |аw. Еvolutionary historiеs arе гесonstruсtеd from a widе variеty of еvidеnсеthat rangеs from sеquеnсеs of spесiеs and forms in thе fossil rесord to similaritiеs and diffеrеnсеs in thе DNA of ехisting organisms. Thе еvolution of somе fеaturеs,suсh as thе hoovеs of ungulatеs,is vеry wеll undеrstood, whilе thе еvolution of othеrs, partiсularly vеry old fеatures likе thе organеllеsof сеlls, is lеss wеll undеrstood. Thе third idеa is the theorу of еvolution. This rеfеrs not to a suggеstion that еvolution hаs not oссцrrеd or that thе historv of oаrtiсular fеaturеsсannot

Introduсtion Ье rесonstruсtеd Ьut to orrr idеas aЬout thе forсеs that drivе еvolutionarу сhangе.In the Оrigiп Darwin propоsed what today is almost univеrsallyсonsidеrеd thе major forсе in organiс сhangе, natural sеlесtion.But natural sеlесtion is not thе only importаnt еvolutionary forсе; natural sеlесtion opеratеs on thе variation in shapеs, sizеs, and iorпrs of organisms сгеatеd Ьy mutations in thеir gеnеs' and thе rаtе and mirgnitudе of thе сhangеs that arе drivеn Ьy natural sеlесtiоnare govегnеdЬy hоw thosе gеnеsсontrol dеvеlopment. An enormous amount of oЬsеrvation and eхpеrimеnt has doсumеntеd thе aсtion of naturаl sеlесtionand somе of thе gеnеtiс rеsPonsеsto sеlесtion. But modеrn disсovеriеsin gеnеtiсsand dеvеlopmеnt have raisеd many nеw quеstions and guidеd us toward soпrеsurprising answеrs аЬout how all thеsе forсеs сomЬinе to drivе еvolution. Outsidе sсiеnсе thе word еuolution rеfers to a natural proсеss сonsidеrеd the inspiration for а host of soсiologiсal, litеrary, politiсal' philosophiсal, and rеligious idеаs. From writегs еxploring thе animal naturе of humans to psyсhоlogistssеarсhirrgfor thе origirrof humаn Ьеhavior in еvolutionary his. tory to thеologians grappling with thе impliсations of еvolution for ouг undеrstanding of thе Divinе, thе influеnсе of еvolution outsidе sсiеnсе fаг ехсееds that оf any othеr sсiеntifiс disсovеry еvеr madе. And as modеrn сontrovеrsiеs in thе sсhools illustratе, partiсularlу in thе Unitеd Statеs' it pro. vokеs rеасtiolls аlmost аs stгong as issuеssurrounding thе Ьeginningand еnd of hцnran lifе. In this Ьook wе еxplorе all thеsе fасеts of еvolution. Our аuthors prеsеnt thе еvidеnсе for еvolution as faсt from thе fossil rесord to gеnomiсs, illustratе thе histоry оf groups from Ьaсtеriа to Ьirds, and dеsсriЬе our сurrеnt idеas about how гhеsе historiеs and tlris еvidеnсе сamе to bе. Our аuthors also еxplorе tlrе influеnсе of еvoltrtion on plrilosopЬy, rеligion, soсiology, psyсhology, and many othеr arеas and addrеss thе сurrеnt сontгovеrsiеs aЬout thе tеaсhingof еvolution in sсhools.Thе Ьook сovеrs thе historiсal disсoveriеs, suсh as homology, that opеnеd thе path for disсovеring еvolution; thе phеnomena' suсh аs industrial mеlanism, that playеd maior rolеs in inspiring ехpеrimеntal studiеs of еvolution; thе appliсations of еvolutionary prinсiplеs to arеas sееmingly far аfiеld, suсh as сomputеr sсiеnсе;and thе сontributions оf thе major figurеswho shaped thе history
bеhavior. Thеrе arе fс whiсh rеvеal that dеs1 сovеrеd. Not that th. rathеr' thеrе is muсh spесiеs or fеaturеs' pa laг lеvеls' and to rеfinr аstonishing divеrsity с Ьook show пot only h liе and how wе might This Ьook is organi on rhе оvегarсhing tt thought to thе сontro origin of lifе to thе pгс m a j о r f е a t u r е so f е v o аrеas likе molесular е. Thе sесond paгt сonti topiсs. Thеsе inсludе t p е o p l е a г е f а m i l i a r ,t с urеs in thе disсovегy Ьоoks that rесount tht

a disсiplinе' This organizat\on a or hеr intегеstsand Ь; thе sсiеnсе сan foсus < intеrеstеd in thе intеlI sсiеnсе сan еntеr throl spесifiс topiсs or hist with еssays on rеlatеd pеlling introduсtion to point thе way towaгd biЬliogгaphiеsw , hiсh Although wе hopе t volumе to inform, ес sсholars. Wе find еvol intеrеsting, and indес еmеrgе with thе samе t i o n , i t i s i m p o г t a n tt .

сhallеngе of antiЬiot tious disеasеs,it shor a l t е r a t i о n so f h a Ь i r a t ехplanations of who '

m a n y o f o u r с l o s е l yh Тhе last of thеsе r Provеn so сontrovеrs pеoplе in thе Unitеd S of lifе on еarth. lt is u

lпtroductioп thе lЪrсеs thаt dгivе еvolutionary hat today is almost univеrsallyсon:, natural sеlесtion'But natural sеarу forсе;nаtuгаlsеlесtionopегatеs ms of organisms сrеated Ьy mutaragnitudе of thе сlrаngеs that arе y how thosеgеnеsсontrol dеvеlopln and ехpсrimеnthas doсumеntеd f the gеnеtiсrеsponsеsto sеlесtion. еvеlopmеnt havе raisеo many nеw lrising answеrsabotrthow all thеsе :rs to а naturаl Proсеss сonsidеrеd l, litеrary, politiсal, philosophiсal, lg thе animal naturе of humans to цmаn bеhavior in еvolutionary hispliсationsof еvolution for our unоf еvolution outsidе sсiеnсе far ry еvеr madе. And as modеrn сonr l a r l y i n t h е U n i t е d S t a t е s 'i t р r o ;urroundingthе Ьеginning and еnd of еvolution.our authors prеsеnt rе fossil rесord to gеnomiсs, illusto Ьirds, and dеsсriЬеOur сurrеnt :vidеnсесamе to Ье. our authors n philosophy, rеligion, soсiology, addrеss thе сurrеnг сontrovеrsiеs Thе Ьook сovегsthе historiсal dishе path for disсovеring еvolution; sm' that playеd major rolеs in inthе appliсations of еvolutionary rсh as сomputеr sсiеnсе; аnd thе lеd thе history of еvolutionarysсints еvolutionarysсienсeas a modssionsof еvolution outsidе thе sсisubjесt Ьесamе fossilizеd in thе lhеn thе suitaЬilityof еvolution as rеingarguеd.Thе irоny is thаt thе ular Ьiology to сomputational inсе that Darwin сould only drеam c сomе appliсations that Darwin Lianmеdiсinе.Prinсiplеs of еvolu.sсiеntifiсproЬlеms, from undег]sеrvation to ехplaining human

Ьеhavior. Thеrе arе fеw topiсs in sсiеnсе with so many еxсiting nеw faсеts' whiсh rеvеal that dеspitе all wе havе lеarnеd, thеrе is muсh morе to Ье disсovеrеd. Not that thеrе is fuгthеr neеd to suЬstantiatе еvolution as faсt; rathеr' thеrе is muсh morе to Ье donе to traсе thе еvolution of groups of spесiеsor fеaturеs, partiсularly сomplеx fеaturеs аt thе сеllular and molесular lеvеls, and to rеfinе our thеory of еvolution to aссoцnt morе fully for thе astonishing divеrsity of lifе as wе сontinuе to disсovеr it. Thе еssays in this book show not onlу how far wе havе сomе but whеrе thе sсiеntifiс horizons liе and how wе might movе toward thosе horizons. This Ьook is organizеd into two parts. Thе first part сontains long еssays on thе ovеrarсhing thеmеs in еvolution. From thе history of еvolutionary thought to thе с
хi

Introduсtion undеrstanding of еvolution and thе еvidеnсе aЬout it and how muсh is Ьasеd on thе сhallеngеs that it offеrs. Yеt opposition to еvolution Ьy rеligious pеoplе, еspесialiy Ьy Сhristians' is Ьy no mеаns inеvitaЬlе; somе of thе'most distinguishеd Ьеliеvеrs havе aссеptеd еvolution without many qualms. NИе arе сonvinсеd that thе Сhristian-with thе Jеw and Мuslim and other rеligious bеliеvеrs-should Ье at thе hеad of thе quеuе of thosе who welсomе evolutionary idеas. Finding thе idеa, Ьuilding and еlaЬorating upon it, and looking at its influеnсе and importanсе arе' as thе сontriЬutors to this volumе show again and again, truly thе Ьеst of proofs that wе arе madе in thе imagе of God, сеlеЬrating сrеation in all its wondеrful manifеstations. This Ьook is a tеstamеnt to onе of mankind's 8rеatеst disсovеriеs, a disсovеry that offеrs unparallеlеd insight into what сrеation rеally is. Iй/еlovе еvolution, and if wе and our fеllow сontriЬutors сan inspirе you еvеn in a small way with our еnthusiasm' thеn wе shall Ье happy indееd.

Thе Hir Thougt

NIiсbаеlR

Thе idеa that all org mеans from othеr forl (fifth сеntury в.с.в.) tr еightееnth сеntrrry an( idеa of natural dеvеlo portеrs. Тhеrе arе rеa Ьеgan to gain momеnl

Thе Еarly Days

Thе Grееks had no grt turе did not havе a plz Spесifiсally, thе Grееk going, inсrеmеntal o Plato and Aristotlе-l isms) showеd ordеr ал simply havе appеarеd tainly was not somеtt thе сomplехity of tod; and dеsign: ..Sinеw,sl and toеs. Thе miхturе of a singlе stuff, a piес on to put things in сol

Now thеse Werе ml nеnt сausе of its prс gеnеrations: our сI rеalm of wild Ьеast ular thеy knеw that and сlaws or hoofs

се aЬout it and how muсh is Ьasеd tion to еvolution Ьy rеligious pеors inеvitablе;somе of thе most dis.!7е on without many qualms. arе w and Мuslim and othеr rеligious rеuеof thosе who wеlсomе еvolud еlaЬorating upon it, and looking сontributors to this volumе show that we arе mаdе in thе imagе of [ul manifеstations. indЪ grеatеstdisсovеriеs,a disсov.s7е lat сrеation rеally is. lovе еvo. )rs сan inspirе you еvеn in a small happy indееd.

Thе History of Еvolutionary Thought Мiсhаel Ruse

Thе idеa that all organisms (inсluding humans) arе gеnеratеd by natural mеans from othег forms has anсiеnt roots. Aristotlе tеlls us that Еmpеdoсlеs (fifthсеntury в.с.в.) toyеd with suсh thoughts.Howеvеr, it was not until thе еightееnthсеntury and thе Еnlightеnmеnt that еuolutioп (as wе now сall this idеa of natural dеvеlopmеnt) rеally startеd to gain a sеrious numЬеr of sup. portегs. Thеrе aге rеasons Ьoth for thе long dеlay and why thе idеa finally Ьеganto gain momеntum.

Thе Еarly Days Thе Grееks had no grеat rеligious oЬjесtion to еvolution, Ьut thеir world piсturе did not havе a plaсе for any kind of signifiсantdеvеlopmеntalproсеsses. Spесifiсally,thе Grееks thought that thеy had irrеfцtaЬlе rеasons to rеjесt ongoing, inсrеmеntal organiс сhangе. Thеy-partiсularly thе philosophеrs Plаto and Aristotlе-thought that thе world (еspесially thе world of organisms)shоwеd ordег and intеntion and, as suсh, was not somеthing that сould simply havе appеarеd thrоugh Ьlind, ungovеrnеd proсеssеs of law. It сеrtainly was not somеthing that сould havе grown from simplе Ьеginnings to thе сomplехity of today. Plato usеd human fingеrnails as an ехamplе of ordеr and dеsign: ..SinеW,skin and Ьonе wеrе intеrwovеn at thе еnds of our fingеrs and toеs. Thе miхturе of thеsе thrее was driеd out' rеsulting in thе formation of a singlе stuff' a piесе of hard skin, thе samе in еvеry саsе.'' Plato tЬеn wеnt on to put things in сontеХt. Now thеsе wеrе mеrеly auxiliary сaцsеs in its formation-the prееminеnt саusе of its produсtion was thе purposе that took aссount of futurе gеnеrations: our сrеators knеw that onе day womеn and thе wholе rеаlm of wild Ьеastswould onе day сomе to Ье from mеn, and in partiсular thеy knеw that many of thеsе offspring would nееd thе usе of nails and сlaws or hоofs for many purposеs. This is why thеy took сarе to

The Historу of Еuolutioпаrу Thought inсludе nаils formеd in a rudimеntaгy Way in thеir dеsign for humаnkind, right at thе start. This was thеir rеasoц, thеn, and thеsе thе profеssеd aims that guidеd thеm in making skin, hair and nails grow at thе еxtrеmitiеs of our |imЬs. (Timаеus, 76d_e, in Сoopеr 1997, 1277)

humаn thought and pгogrеss. Thе British physiсi; Сharlеs) Was a para mankind:

In an inсrеdiЬly influеntial disсцssion, Aristotlе in Dе pаrtibиs аnimаlium (1,984\identifiеd thе faсtors at work hеre as ..final сausеs.'' Thеsе arе сausеs that oссur not just to produсе or do somеthing (thе fingеr parts dry and makе пails) Ьut foг the sakе of somе kind of purposе (thе nails protесt thе fingеr еnds). Thеy show somе kind of forethought or intеntion. For this rеason, fi. nal сausеs сannot Ье rеduсed to Ьlind, unguidеd law, as is dеmandеd in еvolution. Thе world, partiсularly thе world of orgаnisms' must in somе sеnsе havе Ьееn dеsignеd rathеr than just produсеd undеr its own stеam tly natuгal proсеssеs.(Sеdlеy2008 is thе dеfinitivеstudy.) Thе Jеws, and following thеm thе еarly Christians, had religious rеasons for thе rеjесtion of еvolution. It goеs against thе сrеation storiеs of thе еarly сhaptеrs of Gеnеsis, whiсh portray a world сrеatеd miгасulously Ьy God and thеn pеoplеd Ьy him through divinе fiat ovеr a short timе span. But do not think that rеligion as suсh was thеn and always an aЬsolutе Ьar to еvolutionism. Thе сhurсh fathеrs (thе major Сhristian thеologians of thе еarly сеnturiеs) workеd toward an undеrstanding оf thе ЬiЬliсal tеxt thаt wоuld allow intегprеtation, partiсularly in thе faсе of advanсеs of sсiеnсе. Sаint Augustinе was еagеr not to lеt anсiеnt сrеation aссounts stand in thе way of modеrn thought. Hе himsеlf, Ьеliеving that God stands outsidе timе, spесulatеd in a kind of protoеvolutionary fashion that thе Divinе had foгmеd sееds of lifе that thеn sprang into full Ьеing whеn thеy wеrе plaсеd hеrе on еarth. Howеvеr' onе should not геad too muсh into any of this. Likе thе Grееks, thе Jеws and Christians wеrе simply not looking in thе dirесtion of еvolution and would havе thought final сausеs an unаnswеrablе oЬiесtion to signifiсant dеvеlopmеntalism. As is wеll known, thеsе kinds of сausеs Ьесamе a founda' tion of onе of thе major proofs of God's ехistеnсе, thе Argumеnt from Dеsign, whiсh movеs frоm dеsign herе on еarth to thе еxistеnсе of thе divinе artifiсеr. .!Иhy, thеn, did еvolution start its rise in the еightееnthсentury? Thе an. swеr is simplе. It was at this time that pеoplе startеd to сhallеngе thе Christiаn piсturе of world histоry-a providеntial piсtuге of a world сrе. atеd Ьy God, whеrе humans arе madе in his imagе Ьut havе fallеn and arе ablе to aсhiеvе salvation only through his undеsеrvеd graсе. Somе Ьеgan to arguе that pеrhaps humans hеld thеir fatеs in thеir own hаnds and сould progrеssivеly improvе thеir own lots. It Was this idеa of pгOgrеssthе Ьеliеf that thе world and its dеnizеns arе on a trajесtory upward аnd that this upward risе is madе possiЬlе Ьy (and only Ьy) thе unaidеd еfforts of thе world's human inhabitants-that gavе risе to thе idеa of organiс еvolution (Rusе 1996). Еnthusiasts for progrеss ехtеndеd thеiг thinking into naturе and dеvеlopеd thе idеа of еvolution-progrеssivе сhangе upward from thе simplе to thе сomplех. They thеn rеad this idеa Ьaсk into

Impе: Of la With And r Arost An еr (Е.D This is all rhе еnd pr. gеnсе' whiсh сausеs а

Hоw lo From е. Нow fr. Тhе pilt

Similar idеas wеrе tс Pbilosophiе zoologiq produсеd thе first ful to our own spесiеs fr Ьееn produсеd from l ity and othеr natural Although thе mеta1 risе of еvolutionary i< еvidеnсе. Aristotlе ha shaге сommon pattеrl

and thе еvolutionists triеs (Figurе 1). Likеr 8o unnotiсеd (Figurе sition. Thе fossil rес would invokе first as ful. As a systеmatiс p

were mеagеr indеed. faсt that no onе haсl l lцtion. Мost assцm forсеs, Ьut littlе mor that сharaсtеristiсsa ately to thе futurе g

that thе inhеritanсе Lаmаrсkism*Ьut bt

Thе Historу сэfЕuolutioпаrу Thougbt fу waУ in thеir dеsign for huthеir rеason, thеn' and thеsе thе king skin, hair and nails grow at 76d-r, in Coopеr 1997,|277) 'ristotlе iп Dе pаrtibиs апimаlium as ..final сauses.''Thеsе arе сausеs :hing (thе firrgеrparts dry and makе urposе (thе nails protесt thе finger ;ht or intеntion. For this rеason, figuidеd law, as is dеmandеd in еvoof organisms)must in somе sеnsе сеd undеr its own stеam by natural

udv.)

y Сhristians,had rеliglous rеasons nst thе сrеation storiеs of thе еarly d сгеatеdmiraсulously Ьy God and эvеr а short timе spаn. But do пot lwаys an absolutе Ьar to еvolutionstian thеologians of thе еarly сеn'f thе ЬiЬliсal tеxt that would allow dvanсеs of sсiеnсе.Saint Augustinе ounts stand in thе way of modеrn tands outsidе timе, spесulatеd in a rе Divinе had formеd sееds of lifе F wеге plaсеd hеrе on еaтth. How. , any of this. Likе thе Grееks, thе ng in thе dirесtion of еvolution and wеraЬlеoЬjесtion to signifiсant dеkinds of сausеs Ьесamе a foundaj's ехistеnсе, thе Argumеnt from еarth to thе ехistеnсе of thе divinе n thе еightееnthсеntury? TЬе an: pеoplе staгtеd to сhallеngе thе ovidеntial piсturе of a world сrеhis imаgе Ьut havе faliеn and are is undеsеrvеdgraсе. Somе Ьеgan ir fatеs in thеir own hands and )ts.It was this idеa of progrеssi arе on a trajeсtory upward and (and only Ьy) thе unaidеd еfforts gаvе risе to thе idеa of organiс progrеss еxtеndеd thеir thinking .olution-pгogrеssivе сhаngе up1еy thеn rеad this idеa Ьaсk into

human thought and soсial praсtiсе as сonfirmation of thеir Ьеliеfs about progrеss. Thе British physiсian and man of sсiеnсе Еrasmus Darwin (grandfathеr of Сharlеs) was a paradigm who hymnеd in vеrsе lifе's upward risе to humankind: Impеrious man, who rulеs thе Ьеstiаl сrowd, of languagе'rеason' arrd rеflесtionproud, .With brow еrесt who sсorns this еarthy sod, And stуlеshimsеlf thе imagе of his God; Arosе from rudimеnts of form and Sеnsе, An еmЬryon point' or miсrosсopiс еns! (Е. Darwin 180З' 1: Сanto I,linеs з09-з14) This is all thе еnd produсt of thе progrеssivеdеvеlopmеnt of human intеlligеnсе,whiсh сausеsarrd is rеflесtеdin humans' sсiеntifiсaсhiеvеmеnts: How lovеs аnd tastеs,and svmpathiеsсommеnсе From еvanеsсеntnotiсеs of sеnsе; H
3

4

The Нistorу of Еuolutioпаrу Thought A

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Figurе 1. Homologiеs. Thеse аre thе forelimЬs of (froп lеft to right) the Ьat (its wing), the porpoisе(itspaddlе),thе horsе (itsleg),and thе human (its arm). Thе Ьonesarе oЬviouslysimi[ar,аs if modеledon a singlеаrсhetypе'and yеt thе usеs to whiсh thеy arе Put arе verУ diffеrеnt.It was thе British anatomlst Riсhard owеn who сallеd them ..homologiеs'''аlthough it wаs not until аfter Darwin's on thе origiп of Spесiеs(1859)that thеy Ьесamеuniversallyaссеptеd as proof of desсеntfrom a сommon аnсestor.

Thе idеology of progrеss was whаt сountеd, and it was for this rеason that most pеoplе around 1800 would havе rеgardеd еvolutionism lеss as a rеal sсiеnсе and moге as a pгеtеndег,sоmеwhat likе animal magnеtism (mеsmеrism) and thе rеading of сharaсtеr from skull shapе (phrеnology). Еvеn !udgеd by thе standards of that timе, еvolution was what may fairly Ье сallеd a psеudosсiеnсе. OЬviously, Сhristian opponеnts of еvolution dislikеd intеnsеly the antiprovidеntial undеrpinnings of thе doсtrinе. But еvolution was not assoсiatеd with total nonЬеliеf, athеism, or еvеn what latеr in thе ninе. tееnth сеntury Thomas Hеnry Huxlеy was to сall agnostiсism. Мost еvolutionists wеrе dеists who Ьеliеvеd in God as unmovеd movеr' a Ьеing who had sеt thе world in motion and now lеt it unfurl without nееd сlf miraсulous intеrvеntion. For thе dеist' indeеd, еvolution was proof of God,s powеr and intеntion rathеr than disproof. Еvеrything was plannеd Ьеforеhаnd and wеnt into еffесt through thе lаws of naturе. In Еrasmus Darwin's words: ..\)Иhatа magnifiсеnt idеa of thе infinitе powеr of тнв GRЕAT ARснITЕсT! Tнв сдusв oF сAUsЕs! PARЕNT oF PARЕNTS!ЕNs ЕNTIUМ!' (1801' 2: 247|. Thеrе is a link hеrе, еspесially in Еngland, with thе Industrial Rеvolution. Pеoplе wеrе harnеssing thе forсеs of naturе-watеr, сoаl' and othеrs-to produсе goods through maсhinеs rathеr than Ьy hand. Thе god of thе dеist was thе ultimatе

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Figurе 2'Prize pig. Al сountrysidе and go to on thе land to produс rеvolution, and at thе mаjor kеy to suссessl hаiriеr shееp,and Ьig

divinе industгialist a of thе world througt Critiсs of еvoluti Gеorgеs Сuviеr, m; mummifiеd bodiеs o from Еgypt. Althou1 tеmporary forms an, with thе positivе сat that rеally сountеd. hatrеd of a doсtrinе than thеy сould dо z lution, whеn oppon. provеd truе and saft as for еvеry othеr o final сausе. Thе Frе not Ье ignorеd; indr lifе. Thе kеy to unс

The llistorу of Еuolutioпаrу Thought A

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os of (from left to right) thе Ьat (its s lеg),and thе humаn (itsarm). Thе r a singlearсhеtypе,and yet thе l г w a sr h е B r i г i s hа n a t o m i s r s,''althoughit wаs not until after at thеy Ьeсameunivеrsallyaссеptеd

tеd, and it was for this rеasоn that 4aгdеdevolutionism lеss as a rеal hat likе animal magnеtism (mеsm skull shapе (phrеnology). Еvеn tion was what may fairly bе сallеd |Ponеntsоf еvolution dislikеd inof thе doсtrinе. But еvolution was m' or еvеn what latеr in thе ninеs to сall agnostiсism.Мost еvoluunmovеd movеr' a Ьеing who had ш] without nееd of miraсulous inwas proof of God's powеr and inlas plannеd Ьеforеhand and wеnt lrasmus Darwin's words: "What a нЕ GRЕATARсHITЕсT! Tнв сдusв tuм!'' (1801,2: 247).Thеrе is а ndustrialRеvolution. Pеoplе wеrе al, and othеrs-to produсе goods э gоd of thе dеist was thе ultimatе

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Figure2. Prizе pig. An industrial rеvolution means that pеople lеavе thе сountrysidеand go tо thе faсtoriеsin thе сitiеs. Неnсе, far fеwer peoplе аге left on the land to produсе thе nation's food. Thеrе has to Ье an agriсultural revolution,and at thе еnd of thе еightеenthсеntury pеoplе disсovеrеdthаt a major key to suссesswas thе Ьrеedingof Ьеttеr-qualitylivеstoсk-fattеr pigs' hairiеrshеep,and Ьiggеrсattlе.(From Punсh, |865.)

divinе industrialist as hе harnеssеd thе forсеs of naturе to produсе thе goods of thе world through law rathеr than miraсulously or Ьy hand. Сгitiсs of еvolution, notаЬly thе grеаt Frеnсh сompаrativе anаtomist Gеorgеs Сuviеr, madе rеfеrеnсе to еmpiriсal proЬlеms. Cuviеr сitеd thе mummifiеd Ьodiеs of humans and animals Ьrought baсk Ьy Napolеon's army from Еgypt. Although thеy wеrе vеry old, thеir forms wеrе idеntiсal to соntеmPorary foгms and hеnсе сountеd against ongoing оrganiс сhangе' But as with thе positivе сasе for еvolution' in thе nеgativе сasе it was thе idеology that rеally сountеd. AЬovе all, for Сuviеr, thеrе was hatrеd of progrеsshatrеd of a doсtrinе that had lеd humans to think that thеy сould do morе than thеy сould do and had lеd ultimatеly to thе tеrrors of thе Frеnсh Rеvolution, whеn opponеnts of thе ехisting statе had triеd to сhangе all that had provеd truе and safе for mаny gеnеrations. СomЬinеd with this, for Cuviеr, as for еvеry othеr opponеnt of еvolution, was thе still-цnsolvеd problеm of final сausе. Thе Fгеnсhman еmphasized that this was somеthing that сould not Ье ignorеd; indееd, it was thе most important distinguishing fеaturе of lifе. Thе kеy tо undеrstanding thе organism lay in thе fасt that it was not

5

Thе Historу of Еuolutioпаrу Thought simply suЬjесt to thе physiсal laws of naturе Ьut was organizеd. Thе parts wеrе dirесtеd to thе еnd of thе funсtioning wholе, and еaсh individual fеa. turе playеd its rolе in thе ovеrall, purposе-dirесtеd sсhеmе of things: Natural history nеvеrthеlеss has a rational prinсiplе that is ехсlusivе to it and whiсh it еmploys with grеat advantagе on many oссasions; it is the сoпditioпs of eхisteпсe or' popular|у, fiпаl саusеs. As nothing may ехist whiсh doеs not inсludе thе сonditions whiсh madе its еxlstеnсе possiblе, thе diffеrеnt parts of еaсh сrеaturе must Ье сoordinatеd in suсh a Way as to makе possiЬlе thе wholе organism, not only in itsеlf Ьut in its rеlationship to thosе whiсh surround it, and thе analysis of thеsе сonditions often lеads to gеnеral laws аs wеll foundеd as thosе of сalсulation or еxpеrimеnt. (Сuviеr 1817' 1: 6\ Сuviеr's point simply was that thе organism is far too intеgratеd-organizеd and сomplех-to allow signifiсant сhangе in any dirесtion. It is сеrtainly too intеgratеd to allow сhangе from onе spесiеs to anothеr. organisms at mid. point would Ье litеrally nеithеr fish nor fowl and hеnсе would simply Ье unaЬ]еto еxist or survivе. Еvolution was in somе sеnsеa thеorеtiсal impossiЬility, as wеll as еmpiriсally unfoundеd. Rеligion was involvеd too. Progrеss goеs against thе Сhristiаn doсtrinе of Providеnсе. Nеvеrthеlеss, although Cuviеr thought that thеrе was еvidеnсе of Noаh's flood, nеithеr hе nor othеr serious sсiеntists wantеd to makе thе сasе by simplе rеfеrеnсе to Gеnеsis. Indееd, Ьy thе Ьеginning of thе ninеtееnth сеntury' all wеrе starting to rеalize that thе еаrth's history must Ье far oldеr than thе traditional 6,000 yеars that onе сan work out from thе gеnеalogiеsgivеn in thе BiЬlе. It is not that thе BiЬlе is falsе, Ьut rathеr that it nееds intеrprеtation. Somе solved thе proЬlеm Ьy thinking of thе siх days of сrеation as siх long pеriods of timе; othеrs solvеd it Ьy supposing that thеrе wеrе long, unmеntionеd gaps Ьеtwееn thе ЬiЬliсal days. God's сrеation thеreforе was a long, drawn-оut proсеss' Ьut it was not еvolutionaгy. Thе сontrovеrsywas at an impassе,and not muсh had сhangеd Ьy thе middlе of thе ninеtееnth сentury. on the onе sidе wеrе thе еvolutionists' сommittеd to progrеss and ardеnt in thеir Ьеliеf that organiс dеvеlopmеnt was thе perfесt сomplеmеnt to this idеology, with еnthusiasm outstripping еmpiriсai knowlеdgе. Сonfirming this pattеrn' ]n 1844 thе Sсottish puЬlishеr Robеrt СhamЬеrs wrotе (anonymously)a highly popular work on еvolution, Vеstiges of tbе Nаtиrаl Historу of Сrеаtioп, in whiсh hе arguеd that еvеrything was in a statе оf upward Ьесoming and that whаt happеnеd in thе soсial world mirrorеd what happеnеd in thе Ьiologiсal world: Thе quеstion whеthеr thе human raсе will еvеr advanсe far Ьеyond its prеsеnt position in intеllесt and morals, is onе whiсh has еngagеdmuсh attеntion. Judging from thе past' wе сannot rеasоnaЬly douЬt that grеat advanсеs arе yеt to Ье madе; Ьut if thе prinсiplе of dеvеlopmеnt Ье admittеd' thеsе arе сеrtain, whatеvеr may Ье thе spaсе of timе rеquirеd for thеir rеalization. A progrеssion rеsеmЬling dеvеlopmеnt may Ье traсеd

in human naturе, t Now all of this is i of organiс сrеation thе hour hand is t wе do of that lattс rеtrogrеssion of th. missiЬlе, but a forl Ьеrs 1846, 40040

On thе othег sidе aЬout thе signifiсanс modifiеd Ьut thinkin1 еral man of Sсottish gеrs: ..It would augеl wеrе infесtеd with th taintеd with Matеria rеflесtions that still fi thе slaсknеss of sсho diсating thе unsoun< startеd into puЬliс fa. еnсе, and of sapping tеrеstingly' this kind viеws. Although, fro fеlt thе nееd to makr aЬovе is from thе fifl morе сrеdit to thе Cr of сoursе, nеithеr rеal еvidenсе, and fin all to miraсlе may Ье good sсiеntifiс soluti<

Charlеs Darwin

Сharlеs Robеrt Darl train in thе family droppеd out, Ьorеd r rеady Darwin had st еstеd in thе living w anatomist and an а-v work (thе young Сh' tion was an idеa to r nеvеrthеlеss, that thl wholе of Сhristianit; was a faсtor in his rе thе еstaЬlishеd Chur'

Тbе Historу of Еuolutioпаrу Thought LturеЬut was organizеd.Thе parts ng wholе, and еaсh individual fеa'-dirесtеdsсhеmеof things: lnal prinсiplе that is еxсlusivе to /antagеon maпy oссаsions;it is |у, fiпаl саusеs.As nothing may litions whiсh madе its ехistеnсе turе must bе сoordinatеd in suсh гganism'not only in itsеlf Ьut in Lit, and thе analysisof thеsесonvеll foundеd as thosе of сalсula;m is fаr too intеgrаtеd-organizеd , in any dirесtion. It is сеrtainly toо ;iеsto anothеr. organisms at midlwl and hеnсе would simply Ье unmе sеnsеa thеoгеtiсalimpossiЬility, эs agаinst thе Christian doсtrinе of lr thought that thеrе was еvidеnсе ious sсiеntists wantеd to makе thе эеd, Ьy thе Ьеginning of thе ninеthаt thе еаrthъ history must Ье far at onе сan work out from thе gеthе BiЬlе is falsе' Ьut rаthеr that it Ьlеm Ьy thinking of thе siх days of .s solvеd it Ьy supposing that thеrе ЬiЬliсal days. God's сrеation thеrеWas not еvolutionary. not muсh hаd сhangеd Ьy thе mid: s i d е w е r е t h е е v o l u t i o n i s t sс' o m liеf that oгganiс dеvеlopmеnt was i t h е n t h u s i а s mo u t s t r i p p i r r еg m p i r ,, in \844 thе Sсottish puЬlishеr highly popular work on еvolution, lz, in whiсh hе arguеd that еvегyand that what happеnеd in thе soЬiologiсal worid: will еvеr advanсе faг Ьeyond its is onе whiсh has еngagеd muсh LnotrеasonaЬlydoubt that grеat prinсiplе of dеvеlopmеnt Ье adЬе thе spaсе of timе rеquirеd for ing dеvеlopmеnt may Ье traсеd

in human naturе' Ьoth in thе individual and in largе grouPs of mеn . . . Now all of this is in сonformity with what wе havе sееn of thе progrеss of orgaпiс сrеation. It sееms Ьut thе minutе hand of a watсh, of whiсh thе hoцг hand is thе transition from spесiеs to spесiеS. Кnowing what wе do of that lattеr transition' thе possiЬilitу of a dесidеd and gеnеral rеtrogrеssionof thе highеst spесiеs towards a mеanеr typе is sсaгсе admissiЬlе, Ьut a forward movеmеnt sееms anything Ьut unlikеly. (ChamЬегs 1846.400402| on thе оthеr sidе wеrе thе opponеnts' сommittеd to Providеnсе, voсаl aЬout thе signifiсanсе of final сausе' and aссеpting that Gеnеsis must Ье modifiеd but thinking that this сould Ье rеadily donе. David Brеwster' gеnеral man of Sсottish sсiеnсе and Ьiographеr of Nеwton, сould sее thе dan. gеrs: ..It would augеr ill for thе rising gеnеration, if thе mothеrs of Еngland wеrе infесtеd with thе еrrors of Phгеnology: it would augеr Worsе wеrе thеy taintеdwith Мatеrialism.'' Thе proЬlеm, Brеwstеr gloomily сonсludеd with rеflесtionsthat still find muсh support in many сirсlеs today, stеmmеd from thе slaсknеss of sсhools and univеrsitiеs: ..Prophеtiс of infidеl times, and indiсating thе unsoundnеss of our gеnеral еduсation, .Thе Vеstigеs . . .' has staгtеdinto puЬliс favour with a fair сhanсе of poisoning the fountains of sсiеnсе)and of sapping thе foundations of rеligion', (BrеWstеr1844' 503). (Intеrеstingly, this kind of attaсk sееms to havе сonfirmеd СhamЬers in his viеws. Although, from thе start, progrеss was thе lеitmotif of his Ьook' hе fеlt thе nееd to makе his point еvеr morе еxpliсit. Thе passagе just quotеd aЬоvе is from thе fifth еdition of Vеstigеs and rеplaсеs a passagе that givеs morе сrеdit to thе Сrеator. [Figurе 3]) of сoursе, nеithеr sidе was геally satisfaсtory. Idеology is no substitutе for rеal еvidсnсе, and final сausе сan bе ignorеd Ьut doеs not go away. Rеfеrгing all to miгaсlе may Ье soсially and psyсhologiсally сomforting, Ьut it is not a good sсiеntifiс solution. Thе timе had сomе for a signifiсant stеP forward.

Charlеs Darwin Сhагlеs Robеrt Darwin (1809_1882) was sеnt to Еdinburgh Univеrsity to train in thе family tradition of mеdiсinе (Figurе 4). Aftеr two yеars hе droppеd out, Ьorеd with thе lесturеs and геvoltеd Ьy thе opеrations. Yеt alгеady Darwin had startеd to miх with sсiеntists, еspесially naturalists intеrеstеdin thе living world. Onе of his aсquaintanсеswas RoЬеrt Grant, an anatomist and an avowеd еvolutionist. So, quitе apart from his grandfathеr's woгk (thе young Сharlеs rеad Еrasmus's major trеatise,Zooпomia), еvolution was an idеa to whiсh Darwin was introduсеd at an еarly agе. It sееms' nevеrthеlеss,that thе youthful Darwin aссеptеd in a fairly litеral form thе whоlе of Сhristianity, inсluding thе еarly сhaptеrs of Gеnеsis, and that this was a faсtor in his rеdirесtеd сhoiсе of а сarееr: to Ье an ordainеd ministеr in thе еstablishеdСhurсh of Еngland. To aсhiеvе this еnd onе nееdеd a dеgrее

8

The Historу of Еuolutionarу Tbought

B R

Figurе 3. СhamЬеrs'sеvolution.This is the piсturеof еvolutionthаt СhаmЬеrs gаve in Vestiges of thе Nаturаl Historу of Сreаtioп. Apparеntly' for no apparеnt сausе' a primitivе organism wеnt on dеvеloping in thе womЬ аnd tuгned into a fish; thеn a fish Went on dеvеlopingand turnеd intсl a rеptilе;thеn a Ьird; and finally a mammal. Note thе intertwining of thinking abouj the history of thе individual and the history of thе gгoup, somеthiй that wаs to Ьесomе сommonplaсе in evolr'tionarythinking latеr in the ninеiееnthсеntury. (From Vestigеs of the NаturаI Historу of Сreаtioп.|

from an Еnglish univеrsity, and so, in 1828, Darwin was paсkеd off to Сhrist's Collеgе, СamЬridgе. In 1831 Darwin (who сontinuеd mixing with sсiеntists)got his Ьig Ьrеak. Aftеr hе graduatеd, his сarееr as a сlеrgyman Was put on hold through thе offеr of a lеngthy voyagе on HМS Beаgle,just about to start on a survеying trip around South Ameriсa (Figurе 5). A major influеnсеаt this point was (viсariously) thе Sсottish gеologist Charlеs Lyеll, who at thе Ьeginning of thе dесadе Ьegan puЬlishing his massivе Priпсiplеs of Gеolr>gу(thеrе wеrе thrее volumеs; Darwin took thе first with him and had thе othеrs sеnt out). AIthough hе was no еvolutionist, Lyеll insistеd that thе physiсal world must Ье еxplainеd in tеrms of natural сausеs of a kind now still working (Figurе 6). This had a great еffесt on Darwin, whosе first systеmаtiс work was in gеology, аnd prеpaгеd him to think aЬout thе oгganiс world likеwisе lеss in biЬliсal tеrms and morе in tеrms of natural сauses. In 1835, lеaving South Amеriсa, the Beаglе sailеd into thе Paсifiс oсеan and visitеd thе Galipagos Arсhipеlаgo' a 8roЦp of islands on thе еquator, far from land. Thanks to thе governor' who pointеd out that thе giant tortoisеs indigеnous to thе arсhipеlago wеrе diffеrent from island to island, Darwin сamе to sее that this hеld for thе Galipagos fauna gеnеrally-thе Ьirds in partiсular, thе finсhеs and thе moсkingЬirds, wеrе pесuliar to thеir spесifiс homеs (Figurе 7). Thе diffеrеnсеs had to bе signifiсant, and thе only way thе signifiсanсе сould Ье

Figurе 4. Сharlеs Darl 1 8 3 9 j u s t Ь е f o r еh e m l likеnеss(no surprisе's portraitist in Еngland from a very riсh, midd .Wеd wifе' was JosiaЬ mass produсtion.Alth woгk for a living. Thе ехplains wЬу Оn thе | friеndly fashion. Darц Wеdgwood family.

ехplainеd was throu[ Ьraсеdin еarly 1837 liег thinkеrs, what w .Without са еvolution.

The Historу of Еuolutioпаrу Thought

-/B ---B _---F

liсtuге of еvolution that СhamЬers "eаtioп. Apparеntly, for no ,n devеloping in thе woпlЬ and rping and turned into a гeptilе; thеn twining of thinking аЬout thе hс group, something that was to 'ng latеr in the ninеtеenth сеnturY. еаtioп.)

[828, Darwin was paсkеd off to ;with sсiеntists)got his Ьig Ьrеak. an was put on hold through thе of;tаbour to start on а survеying rrip .influеnсе at this point wаs (viсarl, who at thе Ьеginning of thе dе)les of ceologу (thеrе wеrе thrеe and had thе othеrs sеnt out). Alld that thе physiсal world must Ье
Figurе4. СhaгlеsDarwirr'This is а wеddingportrait of Dаrwin, paintеdin 1839just Ьеforеhе marriеdhis first сousin Еmma.Wedgwood.It is a vеry good likеnеss(no surprisе,sinсеthе paintеrwas GеorgеRiсhmond, thе Ьеst portraitistin Еngland at thе tiпrе),whiсh points to thе faсt that Darwin сamе from a vеryriсh, middlе-сiirss family. Onе of his grandfathеrs,sharеdЬy his wifе, wаs Josiаh Wеdgwood, rеsponsiЬlеfor Ьringing thе pottеry tradе lnto massproduсtion.Although hе was a full-timеsсiеntist,Darwin nеvеrЬad to work for a living. Thе faсt that hе was living off thе family fortunе pеrhaps eхplainswЬу Оп tbe Оrigitt of Spесiеswas writtеn in a vеry opеn аnd userfriendlyfаshion.Darwin wаs wгiting ir-rpаrt for his sponsors,thе Darwin.!ilеdgwood family.

ехplainеdwаs through ..dеsсеntwith modifiсation,',an idеa that Darwin еmbгaсеd in еarly 18З7, shortlу after thе Bеаglе voyagе (Figurе 8). Unlikе еarliеr thinkеrs, whаt was of grеat сonсеrn to Darwin was thе сausе or сausеs of еvolution.\Х/ithoutсausеs'hе wаs no morе than onе among many еvolutionists.

9

10

The Historу of Еuolutioпаrу Тbought

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Figurе 5. }{МS Beаgle.The Bеаgle was сaptаinеd Ьy RoЬеrt Fitzroy, thеn only 2З уearsold. Bеing a сaptainon а warship would Ье a very lonеly Post Ьесausе onе would Ье sеt asidе from thе сrеw. Fitzroy thегеforеlookеd for somеonе who сould bе his сompаnionon thе trip, somеonеnot in the navy Ьut а gеntlеmanablе to pay his own bills. Darwin fit thе joЬ pеrfесtly,rapidly еvolving from сaptаin's friеnd to full-timе ship's naturalist.Thе сrеw usеd to сall him ..Philos,''short for Natural Philosophеr_the tеrm thеn usеd for sсiеntists.

.sИithout сallsеs' hе сould nеvеr Ье thе Nеwton of Ьiology. Darwin wantеd to find a biologiсal forсе that would explain thе еvolution of lifе and was univеrsal in thе world and thе kеy Ьеhind all organiс motions' and to this еnd hе workеd fеvеrishlyfor thе nеxt 18 months, spесulatingаnd dоing an ехtеnsivе litеraturе rеviеw. Darwin soon rеalizеd that thе proЬaЬlе kеy to сhangе lаy in somеthing parallеl to thе way in whiсh animal and plant Ьrееdеrsеffесt сhangе, namеly, thе sеlесtiоn of thе dеsiгаЬlе and thе rеjесrion of all othеrs. Brrt how was oDе to gеt a natural еquivalеnt to thе Ьrееdеrs' artifiсial sеlесtion? At thе еnd of SеptеmЬеr 1838 Darwin rеad Аn Еssау on thе Prinсiplе of Popиlаtioz (sixth еdition, 1826| Ьу thе Rеvеrеnd Thomas RoЬеrt Malthus. In his work Мalthus arguеd that food suppliеs would always bе outstrippеd Ьy potеntial population growth. Hеnсе' unlеss thеrе was ..prudеntial rеstraint,'' thеrе wеrе bound to Ье ongoing struggles for еxistеnсе as pеoplе сompеtеd for thе availаЬlе food and suppliеs,inсluding living spaсе (Figurе 9). Darwin turnеd Мalthus's rеasoning on its hеad. Hе pointеd out that thеrе сould Ье no prudеntial rеstraint in thе animаl and plant wоrld' and hеnсе,bесausеpopulation growth сеrtainly Was not rеstriсtеd to humankind, thеrе would Ье an ongoing' organiс-widе strugglе for еxistеnсе. Мorе than this, suссеss and failurе in thе strugglе would (on avеragе) Ье a funсtion of thе diffеrеnt

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Figurе 6. Prinсiples o his mеthodolоgiсalin

Tbe Historу of Еuolutioпаrу Thought

PRINCIPLBS

GЕ o Lo GY, вElIiтG

AN ATгЕlшPт To EхPLAIN TIIЕ FORMЕR сIIANGES oF тIIЕ DARтII'S sURFAcЕ' вY REaEBЕNoE тo сAusЕs Now lN oPEBAтloN.

linеd Ьy RoЬеrt Fitzroy' thеn only lould Ье a vеry lonеly post Ьeсause y thеrеforеlookеd for someonе nеonеnot in the nаvy Ьut a fit thе joЬ pеrfесtly,rapidly ip's naturalist.Thе сrеw usеd to сall --thе rеrmthеn usеdfor sсiеntists.

lton of biology. Darwin wantеd to thе еvolution of ]ifе and was uni'rganiс motions' and to this еnd hе ; p е с u l a t i n agn d d o i n g a п е х t е n s i v е : kеy to сhangе lay in somеthing LntЬrееdеrsеffесt сhangе, namеly, ion of all othеrs. But how was onе ' artifiсial sеlесtion? At thе еnd of tbе Priпсiple of Рopulаtioz (sixth s Robеrt Malthus. In his work rlways bе outstrippеd Ьy potеntial was ..prudеntial rеstraint,', thеrе stеnсеas pеoplе сompеtеd for thе 8 spaсе (Figurе 9). Darwin turnеd ntеd out that thеrе сould Ье no : world, and hеnсе, Ьесausе popuгo humankind, thеrе would Ье an nсе. Мorе than this, suссеss and :) Ье a funсtion of thе diffеrеnt

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Figurе6. Principles of Gеologу' The full titlе of Lyell's work tells you all aЬout his mеthodologiсalintеntions. Еventually, thеrе wеre thrее volumes.

11

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Figurе 7. Thе Gal;ipagostortoisеs.Darwin did not Ьесomean еvolutionistuntil hе rеtrrгnеdhomе and hе сould show his сollесtionof Ьirds to John Gould' a lеadingornithologist.It was whеn hе wаs told that thеrewеrе unаmЬiguously diffеrеnt spесiеstЬаt he movеd асross to еvolution. Notе that еvеn Ьeforе hе Ьесamеan еvolutionist,Darwin was moving in сirсlеswhеrе hе сould сall on thе tоp minds foг supPort and informatioп. He madе powеrful friеnds аt СamЬridgеand thеy spottеdhis talеntеarly.

Figurе 8. Thе trее of lifе. This littlе skеtсh,drawn inJuly 18З7, is from a private notеbook that Dаrwin was kееping on thе sPесiеsproЬlеm. Lаmarсk had а trееof-[ifеpiсturеand in thе еightееnthсеnturyonе сan find thеm in thе writings оf nonеvolutionistswho wеrе nеvегthеlеsstrying to shorмthе oгdеr in whiсh God hаd сrеаtеd.

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rawn in July 1837' is from a privatе lесiеsproЬlem.Lamarсk had a trее. )nесan find thеm in thе writings of g to show thе ordеr in whiсh God

Figurе 9. Thе Мalthusian еxpltlsion. This сartоon appеarеd in the Сomiс Аlmапасk in 1851. Onе of tlrе rеasons thаt l)аrwin was aЬlе to сonvinсе pеoplе of thе truth of еvolrrtion Was' apart frtlrn lris friеndly stylе, thе faсt that hе rеliеd on idеas tlrаt wеrе widеlv ассеrltеd in Viсtorian Britirin.

1З

I+

Thе Historу of Еuolutionаrу Thought сharасtегistiсspossеssеdЬv organisms. Неnсе tl-rеrеwould bе an ongoing natural sеlесtion in whiсh thе winnеrs would pаss on fеaturеs to thе nеХt gеnеrаtion and thе losеrs would gеt nothing. Ovеr timе' this sеlесtion would lеad to full-Ьlown organiс сhangе. But this organiс сhangе would Ье of a partiсular kind' for thе fеaturеs that mаkе for suссеss,known as ..adaptаti6n5''-f61 g;amplе, еars' еyеs' tееth, hands, lеgs, lеavеs, Ьаrk, and roots-would show that purposеful naturе that еpitoпizеs final сirusе. Darwin sat on his еvolutionary idеas for 15 yеars' during whiсh timе hе 's7'е turnеd to a massivе study of Ьarnaсlеs. arе not quitе surе why this dеlay oссurrеd, although Ьy this timе Darwin hаd fallеn siсk with a mystеriousail. mеnt that W21sto plaguе him for thе rеst of his lifе, and so undouЬtеdly hе Was not rеlishing thе hugе dеЬatеtlrat his idеas wеrе Ьound to сausе. Also a major faсtor must havе Ьееn his rеluсtanсе to upsеt powегful sсiеnсееstaЬlishmеntfigurеs (inсluding СаmЬridgе mеntors) who had еnсouragеd thе young Darwin in his work. Onе of thе things hе did during thе pausе was to nеtwоrk with youngеr sсiеnrists'who сould rally around him whеn hе did go publiс. Finally, howеvеr, Dzrrwin was pushеd into aсtion whеn, in thе .Wallaсе, middlе of 1858, hе rесеivеdа short еssay Ьy Alfrеd Russеl a сollесtor in thе Malay pеninsula' that had virtually thе samе prеmisеs and сonсlusion that hе had disсovеrеdsomе 20 yеars еarliеr.

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oN тнЕ oRlGlN oF sPЕсlЕs Darwin quiсkly wrotе up his idеas, and ()n thе Оrigin of Spесies bу Мeапs of Nаtиrаl Selесtion, or thе Preseruаtioп of Fаuсlиred Rасes iп thе Struggle for Lifе appеаrеd in thе fall of 1859 (Figurе 10). Thе work Ьеginswith a disсussion of artifiсial sеlесtion аrrd animal and plant Ьrееdеrs'grеat suссеssеs. This is partly hеuristiс,tо prеparе thе rеаdеr by following thе path thаt Dar. win himsеlf had takеn to disсovеry, and partly justifiсatory,suggеstingthat what wе сan do, naturе сan surеly do Ьеttеr.Following is a disсussion of thе variation thаt аlways oссurs in thе wild, somеthing that Darwin oЬviously nееdеd as thе building Ьloсks of сhangе. If еvсry organism Wеrе еxaсtly likе its parеnts, thеn thеrе сould Ье no еvolution' At this point Daгwirr was rеady to introduсе thе strugglеfor ехistenсеаnd' following on this, thе mесhanisnr of natural sеlесtion: A strugglе for ехistеnсе inеvitaЬly follows fr
Figurе 10. Thе titlе pag сhееky in quoting thе p thе topiс of thе law-gor Dаrwin's mеntorswhеr сontinuеd in this r
Notе that еvеn mor for rеproduсtion. lt is sеxцal dеsirеsof a phi way' givеn naturally с

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Tbe Нistorу of Еuolutioпаrу Thought . Неnсе thеrе would bе an ongoing ould pass on fеaturеsto thе nеxt gеn;. ovеr timе, this sеlесtion would lеad ganiс сhangеwould Ье of a partiсular эss,knоwn as ..adaptation5''-f91 91еs' bark, and roots-Would show that :ausе. for 15 yеаrs, during whiсh timе hе !Ие arе not quitе surе why this dеlay had fallеn siсk with a mystеrious ailst of his lifе' and so undouЬtеdly hе Lisidеas wеrе Ьound to сaцsе.Also a -lсtanсе to upsеt powеrful sсiеnсеidgе mеntors) who had еnсouragеd tе things hе did during thе pausе was сould rally around him whеn hе did as pushеd into aсtion whеn, in thе .sИallaсе, y Ьy Alfrеd Russеl a сollес:uallythе samе prеmisеsand сonсlurs еarliеr.

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oп the Оrigiп of Speсies bу Мeаns n of Fаuourеd Rасes iп the Struggle urе 10). Thе work Ьеginswith a disand plant Ьrееdеrs' grеat suссеssеs. adеr Ьy following thе path that DarI partly justifiсatory, suggеsting that ttеr. Following is a disсussion of thе l, somеthing that Darwin oЬviously If еvеry organism Wеrе ехaсtly likе ion. At this point Darwin was rеady Ld,following on this' thе mесhanism

lws from thе high ratе at whiсh all y Ьеing' whiсh during its natural s' must suffег dеstruсtion during 1е sеason or oссаsionаl yеar' othсal inсrеasе, its numЬеrs would hat no сountry сould suppоrt thе е produсеd than сan possiЬly sur. gglе for еxistеnсе,еithеr onе indi, or with thе individuals of distinсt of lifе. (С. Darwin 1859' 6З)

15

Figurе 10. Thе titlе pagе of Оn tbе Оrigin of Spесiеs.Darwin wаs Ьеing a littlе Whеwеll, oppositеthе titlе pagе' on сhееkyin quotingthе philosophеr.!Иilliam .!Иhеwеll had Ьееn onе of thе topiс of thе law-govеrnеdnaturе of thе univеrsе. Darwin'smеntoгswhеn thе lattеrWas a studеntat СаmЬridgе,аnd hе сontinuеdin this ro1еin thе еarly yеars aftеr tЬe Bеаglе voyagе.Llе was a wеllknown opponеntof еvolutionand was sсathingon thе suЬjесtof Vеstigеs' Darwin sеnt a сomplimеntary сopy of the Оrigiп to.Whеwеll, who rеspondеd by Ьanningthе Ьook from thе shеlvеsof thе liЬrаry of Trinity Сollеgе' of whiсh hе was Mastеr (hеad)

Notе that еvеn morе than a strugglе for еxistеnсе,Darwin nееdеd a strugglе for rеproduсtion. It is no good having thе physiquе of Tarzan if you havе thе sеxualdеsirеsof a philosophеr. But with thе strugglе undеrstood in this sort of Way' givеn naturally oссurring variaгiоn, natural sеlесtion follows at onсе: Сan it . . . Ье thought improЬaЬlе' sееing that variations usеful to man havе undouЬtеdly oссurrеd, that othеr vаriations usеful in somе way to еaсh Ьеing in thе grеat and сomplех Ьattlе of lifе, should somеtimеsoссur in thе сoursе of thousands of gеnеrations?If suсh do oссur' сan wе douЬt (rеmеmЬеringthat many morе individuals arе born than сan possibly survivе) that individuals having any advantagе' howеvеr slight, ovеr othеrs, wоuld havе thе Ьеst сhanсе of surviving аnd of proсrеating

tb

The Historу of Еuolutioпаrу Тbrшgbt tlrеir kind? On tlrе othеr hаnd Wе шIаyfееl surе that any r,аrizrtionin thе lеast dеgгее injurious worrld Ье rigidly dеstrсlyеd.This prеsеrvatiorrof favouraЬlеvariations and thе rеjесtionof ilrjurious variations,I сall Nаt. u r а l S е l е с t i t l n(. 8 0 _ 8 1 ) In latеr еditiсlrrsDaгwin intгodtrсеd thе аltегrrаtivеtеrm gtruiuаl of thе fittest, wlriсh was pеrhаps a littlе unfoгtulratе,for it has lеd to еndlеss сlaims that sеlесtion is a tаutolсlgy, rеduсing simply to thе сlairn thаt thosе who survivе arе thosе who survivе. But althouglr this is oЬviously truе, sеlесtionmеans morе than tlrat. It сlaims, ior Ьеttеr сlr fсlr worsе' th21ton аvеragе tlrosе who survivе thosе whtl do not, and thilt suссеssin tlrе strugglе is a funсaге diffеrеnt fгсrr-n tiorr of thosе diffеrеnсеs.This may ()r may not Ье truе, Ьut it is not a tautology. Darwin inсludеd a sесondary sеlесtivе mесhanism. Hе arguеd that thе stгugglеis not always for food irnd spaсе Ьut сan Ье dirесtly foг matеs. This mесhanisrn, sехtlаl seleсtiс>tl, Darwirr dividеd into twtl Pаrts. Thеrе was sеlесtion through пlalе сomЬat (fсlrfе;rralеs). Tlrе antlеrs of thе dееr would Ье thе produсt of this. Тhеn thеrе was sеlесti
Thе anаlogywith anirnalЬrееdinglеd Dаrwin ro Figurе 11. Sеxual sеlесti
lесtion partiсularly pr thе samе spесiеs:sеlес istiсs rаthеr thаn spес sее sеlесtion (inсludin Нaving thus prеsе duсеd thе famous mе samе сlass havе somеl ilе largеly spеaks thе spесiеs еxtant today. еvolutionary paths of vеry first sharеd orig and thеsе, if vigorou Ьranсh, so Ьy gеnеrz whiсh fills with its dе еrs thе surfaсе with i

win 1859, 129-130) Now, with somе prеsеnt thе sесond р Darwin took thе rеa< instinсt, palеontology and showеd that ph through natural sеlес support thе mесhan

Figurе 12. Thе trее < this piсture is lеss or sprеads.

Thе Historу o|.ЕuolutiсllzаrуlT1',,,''' fееl surе that any variation in thе r"dеstroyеd.This prеsеrvation of of injuriousvariаtions'I сall Nat-

tеrnativе tсJm suruiuаl сlf the fittest, ,r it has lеd to еndlеssсlairns that sег Ь ес l а i n lt h а t t h r l s еw h o s t t r v i v еа г е bviously truе, sеlесtion mеаns morе э' that on avеragеthosе who survivе thаt strссеssin thе strtrgglеis а funсnot Ье truе' Ьut it is not a tautology' е mесhanism. Не arguеd that thе bllt сan Ье dlrесtly for mаtеs. This idеd into two parts. Thеге was sе_ ;). Thе antlеrsof thе dееr would Ье :tion through fеr-nalе сhoiсе (of thе or gеnеral plurr-ragе of thе pеaсoсk ; (Figurе11). Notiсе how sехual sе-

h animalЬrееdinglеd Dаrr,vrnto :сtion.Naturаl sеlесtion rеlpsurvival,likе thiсkеrсoars, сtion fоr аttriЬutеsthat givе plеamorе fегoсiousfightingquаlitiеs. [aи.(Bссаusеtl.tе()rigin wаs writtеn or illustrating. Most of Darwin's iouslyillrrstratеd.)

lесtion partiсulaгlyputs thе еmphasis on сompеtition bеtwееn mеmЬеrs of thе samеspесiеs:sеlесtionis dirесtеd toward individual-Ьеnеfitingсharaсtеristiсsrathеr than spесiеs-Ьеnеfiting сharaсtеristiсs.Darwin tеndеd always to (inсluding sееsеlесtion natural sеlесtion)aсting in this way. Having thus pгеsеntеdthе mаin Inесhanisms of сhangе, Darwin intro. duсеdthе famous mеtaphor of a trее: ..Thе affinitiеs of all thе Ьеings of thе samесlasshavе somеtimеsЬееn rеprеsеntеdЬy a grеat trее. I Ьеliеvеthis similе largеly spеaks thе truth.'' Thе lеavеs and twigs at thе top reprеsеnt thе spесiеsеxtant today. Thеn, as wе go down thе branсhеs' wе havе thе grеat еvolutionary pаths of yеstеrday. All thе way down wе go until wе rеасh thе .,As vеry fiгst sharеd origins of lifе. Ьuds givе risе Ьy growth to frеsЬ Ьuds, and thеsе,if vigorous, Ьranсh out and ovегtop on аll sidеs many a fееblеr Ьranсh, so Ьy gеnеration I Ьеliеvе it has Ьееn with thе grеat Trее of Lifе, whiсh fills with its dеad and ЬrokеrrЬranсhеsthе сrust of thе еагth, and сovеrs thе surfaсе with its еvеr branсhing and Ьеautiful ramifiсations'' (С. Darwin 1859, 129_130) (Figuге 12). Now, with soпlе minor problеms brr.rshеdaway, Dаrrvin was rеady to prеsеnt thе sесond part оf his thеory. For a good two-thirds of thе Оrigiп, Darwin took thе rеadеr through thе vaгious Ьranсhеs of Ьiologiсal sсiеnсеinstinсt,palеontology,Ьiogеography,сlassifiсаtion,m
Figurе 12. Thе tгееof lifе аs given in tЬе Оrigiп. Notiсе that thе еmphasis in this piсturеis lеss on showing lifе rеaсhing up and morе on thе way in whiсh it spreаds'

17

18

The Historу of Еuolutiсlпаrl Thought

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Figurе 1.3.Thе struсturеof Darwin's аrgumеnt.l)arwin did not hit Ьy сhanсеon this kind of argumеntаtion,whеrе a unifyir-rg hypсlthesis ехplainsin many 'Whеwеll, diffеrеntarеasand in turn is justifiеdor suрportеdЬl.thеsеаrеas. who сallеd it a ..сonsiliеnсе of induсtiсlns,''madе muсh of it whеn disсr.rssing suссеssfulthеtlriеsof physiсs,еspесiall1' Nеwttlnianmесlrаniсsand thе wavе thеory of light.Whеwеll idеntifiеdthе сirusеsat thе сеntеrof а сonsiliеrrсе аs ..truесausеs,''whаt Nеwttln hаd сallеd Uеrdес(l|tsае. Showinga сonsiliеnсеwas thеrеforеаn еssеntiаlstfatеgyfor а worrld-bеNеwtсlt-lof Ьiology.

Wеrе somе proЬlеmatiс issttеs.Soсial Ьеhlvior, pаrtiсtrlагlyth:rt shown by thе soсial insесts (thе hymеnoptеra-thе ants' thе Ьееs, and thе wasps), would Ье еasily ехpliсaЬlе if sеlесtion favсlrеdthе group. But frсrm an individualistiс pеrspесtir,е,why slror"rldol1е gеt stеrilе lr,orkеrs lvlro sееmirrgly spеnd thеir wholе livеs dеvotеdto thе lvеll-Ьеingof othеrs irl thе nеst or hivе? How сan natural sеlесtion,with its еmphasis on thс importanсе of rеproduсtion, рroduсе organisms that сaлn
would сall thе СаnrЬг е х p l a i n е ds i t n р l уз s e n o l o n g е r Ь е t h е r е ,Ь r . Ьrought out all of D whеrе now thеге Wrrе not find it. Еvеn if wе dotrЬtftll that wе wou prеssеd and mеtamor1 М o s t o t Ь е r а r е a so f triЬr-rtion(Ьiogеograph is that onе finds thе va Why, foг instanсе,doе that arе еxhiЬitеd Ьy tl simply that thе foundе thе mainlаnd, аnd onс. sify undеr thе nеw sе Figurе 7). Systеmatiсs еvolution. As Linnaеu сally in nеstеdsеts,thu МoгpЬology lrаrsthosс diffеrеnt spесiеs.oЬvi. Ьryology likеwisе was . еmbryos of soпrе diffеwhеrеas thе adults аrе faсt thаt in thе wonrЬ similaг (thеywould nor thе rwo adults would l Hеrе' as аlways thгouр analogy with thе worlс ..Fanсiеrssеlесt hand: arе nеаrly 8rown up: struсturеs lrаvе Ьееn a possеssеsthеm'' (С. D' So wе arе lеd to tt Сhristianity lrаd еvolr mеmЬеrs of thе \Х/еd сеаlеd that hе Was W unsеlf-сonsсiousrеfеr sееm to Ье fully satis dеntly сrеatеd.''This r tеr with what wе kno thе produсtion and ех shоuld hаvе Ьееn duс and dеath of thе indi Whаt God doеs not d nеss in supposing oth

Тhе Нistorу of ЕuсllиtiсlпаrуThoцgbt

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ЕmЬryoIogy

lеnt. Dагwin did not hit Ьy сhanсе on lg hypсlthеsisсхрl:rins in many эportеd by thеsе :rrеzrs.Whеwеll, who е n l t l с h r l f i t r rh с n d i s с u s s i n g :wtoniаn mссhаniсs and thе wavе еs at thе сепtеr of a сonsiliеnсе as ае саusае. Showing a сonsiliеnсе was Ье Nеwton of Ьiology.

,havior,partiсr-rlаrlvthat shown Ьy tе ants, thе Ьееs, and thе wаsps)' vorеd thе group. But from an indigеt stеrilе ч,orkегs who sееmingly l-Ьеingof othеrsirr thе nеst or hivе? asis on thе importanсеof rеproduсlroduсе? Finally, Dаrwin, who alovеr group approaсhеs Ьесausе hе Ldехploitation,dесidеdthat in suсh gratеdthat it is pеrnrissiЬlеto trеat r in whiсh thе individшalinsесtsarе lork on thе еvе, ft>rехamplе, whiсh m' so thе u.orkеr ехists fоr thе Ьеnhad its good points-for instanсе, gly wе find orgarrismsthat sееm to )f ехtant organisrтs that arе widеly .hеrеwеrе gaps irr thе fossil rесord, r aЬruptly at thе starг of what wе

would саll thе СzrnrЬriаn;thеrе Was l1()rес()rdЬеforе that' Thе gaps Darwin ехplairrеdsirlplу as a produсt of ilrсtlmplеtеfrrssilization.T.hеrеmains might no longеrЬе thеrе,Ьut thе linking anсеstorsdid еxist. Thе aЬrupt Ьеginning Ьrought out all of Darwin's invеntivе Powеrs. Еarly lifе proЬaЬly еxistеd whеrеnow thегеwеrе oсеans;this would еxplain why wе on dry land сould not find it. Еvеn if wе wеrе aЬlе to drill Ьеnеaththе oсеans, howеvеr, it was douЬtfulthat ъ.е would find lifе; thе prеssurе from abovе had surеly сomprеssеdand mеtirmоrphosеdthе fossil rеmains lrеlow (Figurе 14). Мost othег arеаs of Ьiology fеll int<-l plaсе witlr morе еаsе.Gеographiс disrvas а triumph ЬесаttsеD:rrwin ехplainеd iust why it triЬution(Ьiogеogrаplry) is thаt onе finс]sthе variolts pattеrns of arriпrаland plant lifе aгourrd thе gloЬе. !Иhy, for instаt-lсе, doеs onе havе thе strаngе sorts of distriЬutions and pattеrns that arе ехhiЬitеd Ьy thе Gal5pagos Arсhipеlago and othеr island groups? It is simply that thе ftrundеrsof thеsе isolatеd islirnd dеnizеns сamе Ьy сhanсе from thе mainland, alld onсе thеy wеrе еstaЬlishесl,thеy startеd to еvolvе and divеrsify undеr thе nеw sеlесtivе prеssurеs to wlriсh thеy wеrе now suЬjесt (sее Figurе 7). Systепrirtiсslikеwisе ехhiЬits thе kind of pattеrns onе ехpесts from еvolution. As Lirrrraеttsdеmonstratеd, organisnrs сan bе сlassifiеd hiеrarсhiсallyin nеstеdsеts,tlrusslrowinga pаttегnthat геvеаlspast history (Figцrе 15). Morpholog1,hirs thosе similaritiеs,саllеd lromologiеs,bеtwееn orgаnisms of diffеrеntspесiеs.oЬviously thеsеspеаk to slrarеdanсеstry(sееFigurе 1). ЕmЬryologylikеr,l,isеWas a partiсular point of рrгidеfor Dаrwin. Why is it tlrаt thе еmЬryosof soгtlеdiffеrеnt spесiеs,suсh as man and thе dog, arе vеry similar, whеrеasthе adults arе vеry diffегеnt? Darwin arguеd thаt this follows frorn thе faсt thаt in thе womЬ thе sеlесtivе forсеs on thе two еmЬryos would bе vеry similar (thеywсlr"rldnot thеrеforе Ье torn apart)' whеrеas thе sеlесtivеforсеs on thе rwo adults woшld Ье vеry diffеrеnt(thеy wor"rldЬе torn apart) (Figurе 16). Darwin turnеd to thе Неrе, as always tlrrouglror-rt his disсussions сlf еvсllr-trion, anabg,vr,r,ithtlrе world of Ьrееdеrsin tlrdеr to сlarify and support tlrе point аt sеlесtthеir horsеs, dogs, аrld pigеons, for Ьrееding' wlrеn thеy hand: ..Fiu-rсiеrs arе nеarly gro\vn up: thеy arе indiffеrеrrt rvhеthеr thе dеsirеd qualitiеs аnd struсturеshavе bееn aсquirеd еarliеr or latег in lifе, if thе full-grown animal possеssеs thеm', (С. Darwin 1859,446). So wе arе lеd to thе сonсluding passаgеsof the Оrigiи. Darwin, whosе Сhristianityhad еr,olvеdinto a form of dеisrn (Lyеll, a Unitariаn likе many mеmЬеrsof thе Wесlgwood family' Was а mаjor influеnсе hеrе), nеvеr сon' сеalеd that hе w,:rsr,vсlrkingin a God_Ьасkесl modе, and thеrе arе frеquеnt геfеrеnсеsto thе Сrеаttlг' ..Authors of thе lrighеstеnrinеnсе unsеlf-сonsсiot'ts sееmto Ье fulh. satisfiеdwith thе viеrv tlrlrt еaсh spесiеshas Ьееn indеpеn,.To my mind it dеntlyсrеatесl'''This was not Darwin's ptlsition. aссords Ьеttеr with whаt wе know of thе laws irnprеssеdon mattеr Ьy thе Сrеator' that thеproduсtionalrd ехtinсtion of thе past and prеsеntinhaЬitantsof thе world should havе Ьееn duе to sесondary сausеs' likе thosе dеtеrmining thе birth and dеath of thе irrdividual'' (С. Г)аrwin 18's9' 488). God Ьaсks thе world. What God doеs Irot с1ois gеt involvеd in thе world, and sсiеnсеhas no busin е s si n s u p p t l s i n gr l r h е r r r ' i s е .

19

20

Тhе Hist<.lrу сlf Еuolutioпаrу тABLв

oв STRATA

Tbought дttu Oвpsв or' AРPЕAR,ANолоr Aшrмдr, I,rrв UPoN

o N o z ц o

s

F A, UJ t-

o N

N ц'l

5

ч

o z

o o lrl

U'

TпrЬaгy. Shetl-Мarl. Glacial Drift. i fl Brick EвrtЬ. E8 Noтwiсh 1 Red }Crшg. Comllinе ) Fвlunн. Моlaвse. "" .'"-"-.. Gypr.

BonoBed.-мArи

l!ARтЕ.

Ьy Wеaponв.

Ф 3 . . . ;I

!9o{9n }сt"",. rlаяtlс, Мaеstricht' Uppeг Chalk. Iюweт Chalk'. Uppeт Сlгeensand Iюver Grеensand 'lYeвld Сla1.. ТIaвtingвSan.l PuгЬеck Bеdв. Kimmeгidgian. oхfoгdian. Кellovian. ltoгest Матble. Bath-Stone. StonoвfieldSlшtе' Grеat oolitе. Liдв.

гIlE

й

E fтпgu]аta. Caгnivоrа

s

Cyсloid. l _ Мoввsauгnв. Ci"ooid. l !rg,Еg' РolyptyсЬodoп' Brвоs, Ьу Boneв. Prосrlian Cтoсodilia.

e €

Еl

Iguаnodоn. _l\Iaтsupialв' - Cheloniв Ьy Boneя. P]iosauгuв'

EE o

Мaгsupialв.

"E- * .f:{

Iсthуopteтуgia.

гvrAL|

"{-*-";:":"w

Е.

Е !

Figurе 14. Тhе history of lifе as sееnin 1860. Тhis is takеn trom Riсhard owеn's Pаleoпt
Figuтe 15. Thе Linnaеa w i t h t h е m е m Ь е r so f | o с o m P г е h е n s i v еs)е r sa t l s e t ( k n o w n a s t a х a ,s i n 8 sharеd past' althoughas without rеgardto еvolu interprеtationgavеit nе hypothеsisof shаrеddе

тl1Е DEscENт

|

What аЬout humans? that humans aге part i on thе Bеаgle voyagе Тiеrra dеl Fuеgians' hс сally Darwin dесidеd l want to сonсеal his th points aЬout еvolution mеnts of all timе, hе si and his history.' (С. D thе topiс and dеal wi two-volume work, ТЙ.

Тhe Нistсlrу of Еuolutioпаrу Thougbt

)F APPЕAпANOE or ANIмAт, Т,rFE lдвтц' >1.0o0,oo0speсies

(аnimа|s)

I 6

Н

..-;;H'r't"+$:s Ф d

€

,d.l. Мoввsauгuв.l id. r дl8lrЕs' PoIуptyсЬodоn. I ' Ъy Boneв. l liвn Cтoсodilia. l I

trl

#;dseж rffi

€"*Wehf?

di d

я

.";;i;.^-"6. a--;.;"; ;.

5,,l60 sрeсies

(songbirds)

odoв. pialв,- CheloniшЬy Bonев цгu8.

&ж ldЖ

"-t#

,hyopteгygiш.

i, by Foot-pfints. эtotygia. iдtЬodontia.

'ia, by Toot.pгints. lL|A ganoоерh. Inвeсta

-si

Ei

I ganOld.

Figure15. Thе Linnaеanhiеrarсhy.organisms саn all Ье plaсеd in a hiеrarсhy with thе mеmЬеrsof lowеr-lеvеlsеts Ьеing groupеd into еvеr fеWеr(Ьut morе сomprеhеnsivе) sеtsаt highеrlеvеls.All organismsЬеlongto onе and only onе sеt(knownas taхa, singulartaхon) at еaсh lеvеl (саtеgory).This reflесtsa sharedpast, although as With thе fossil rесord' muсh of this was workеd out without regardto еvolution. Hеnсе, giving thе hiеrarсhy an еvolutionary interprеtationgavе it nеw mеaning and at thе samе timе сonfirmеd thе hypothеsisof sharеd dеsсеnt.

.oф

."f

I plaсo.ganoid.+ig.{ plaоoid.-

ь$1'Ё$:'*:Ъw т

Fuсoids.

zoopl\уI,os.

60. This is takеn from Riсhard wеn Ьесamеan implасaЬlееnemy of е matеrialistiс; Ьut, as young mеn эn proЬaЬlyЬесamеa ing thе сourseof history)'Ьut onе <еthesеas implying еvolution. As re fossil rесord thinking that it might entially сrеatеdorganisms.

21

тl]Е DEscЕNт oF MAN What aЬout humans? From thе first, Darwin was always stonе.сold сеrtain that humans arе part and parсеl of thе еvolutionary proсеss. His еnсountеr on tЬe Bеаglе УoУagewith thе nativеs at thе Ьottom of South Amеriсa, thе Tiеrra dеl Fuеgians' had сonvinсеd him of this. In the origiп, howеvеr, taсtiсally Darwin dесidеd not to makе muсh of thе human quеstion. Hе did not wаnt to сonсеal his thinking; hе simply did not want it to swamp his gеnеral pointsaЬout еvolution and its proсеss.Hеnсе, in onе of thе grеat undеrstatе. mеnts of all timе, hе said mеrеly' ..Light will Ье thrown on thе origin of man and his history'' (С. Darwin 1859' 488). Darwin fully intеndеd to gеt Ьaсk to thе topiс and dеal with it at lеngth. This hе did in 1871, offеring a major two-volumе work,The Desсent of Маn.

22

Thе Historу of Еuolиtiсlпаrу T'htlugbt

naturаlistiс pеrsPесtivе tlе еssay on how humal with spiritualism and с. natural еvеnt. Thеrе ml

}.lg.l.

Uppеl ffgпrеlruвltrп.'rJ}*3f;Ji:kоr'

l,oweтfi$tre thlt of s dog,

Рoff of this сonсlusion, tеristiсs that сould not human hairlеssnеssanс ally livеd with nativеs, powеr unusеd by pril prodцсеd Ьy sеlесtion. thе Thеorу of Nаturаl ' Suсh a сonсlusion w good ar8umеnts. Natul tivе human fеaturеs, Ь that is сharaсtеristiс o Ьеaury and dеsirabilit; .Wаllaсе wеrе not suсh сеrtainly not out of th( sion of sеxual sеlесtio .Why arе mеn Ьig and s сеstors who wеrе got tl domеstiс? Bесausе thе Ьеst joЬ with thе famil; anсеstors found sехua womеn (using Darwin' thе standard of Ьеаut1 Е x p е с t е d l y ,a l l o f t h i s i timеnts aboцt thе геlat dесidеd еminеnсе ovе mеntal powеr in man

326-з27). o. Forе.broln, сeтсtл.оl lrсtпispherсs, tс. r,. ]шld.brдin. с.,rln,г8 (lltа'lгigеn'iПs. с. Ilind.lrraiш. сerеlлllunt, medulla obloug8tд. d. Еуe. с. Iйг.

;f. Fiгst visсегal arсb' g. sосolrdvisсетдlarсh. I{. veгtсbгsl сolurnns and muасltlа in pтшeв:or d0vоloрвr(.ut.

ties. it.**'ltli]l. }ехtгеnri 'Гвil I,.

oг tiв соссyx.

Figurе 16. Similarityof thе еrnЬryoof humirnand dog. Again, Wе sееthе strеngthof the Оrigiп in r.r.raking шsеof fасts likе rlrеsе'wеll known to all Ьiologists.(Еrom ТЙe Dеsсепtrl|-Мап.|

No argumеnt is nеес his thinking wеrе star may havе Ьееn a rеvol triЬе. It is littlе wondеt By univеrsal aссlaim, that Еnglish Valhalla,

Aftег Darwin \й/hеnonе looks at this Ьook, it is rеally rathеr pесuliar. Most of thе Ьook is not on thе lrun-ranspесiеsаt all Ьut сonsists сlf an ехtеndеd еssay on thе seсondary mесlrаnism of sехu,rlsеlесtion.Tlrе pесuliarity of tlrе topiс yiеlds thе сluе to its gеnеsis. Alfrес] Russеl !Иallасе startеd Ьy shaгing Darwin's

Bеforе the origiп was of progrеss, it was op1 to that of mеsmеrisп Darwin сhangе thing was сеrtainly a сultur

The Historу of Еuolutionаrу Thought

f

J

noЕсkсг.

Iюweт figrrrе that olя dog'

naturalistiсpеrspесtivе on human origins and еvеn pеnnеd a stimulating littlе еssayon how humans might havе еvolvеd. But thеn hе Ьесamе еnamorеd with spiritualismand сonvinсеd that humankind сould Ье no сhanсе, purеly natural еvеnt. Thеrе must havе Ьееn a Mind guiding human gеnеsis. In sup.sИallaсе port of this сonсlusion' arguеd thаt thеrе Wеrе many human сharaсtеristiсsthat сould not havе Ьееn thе produсt of natural Sеlесtion, suсh as human hairlеssnеssаnd humans' grеat intеlligеnсе. \Wallасе,who had aсtually livеd with nativеs, maintainеd that thеrе wаs a vast аmount of Ьrain. powеr unusеd by primitivе man, and thеrеforе it сould not havе Ьееn produсеd Ьy sеlесtion. (\7allaсе's еssays arе сollесtеd tnЬts Сoпtribиtioпs to thе Thеorу of Nаturаl Selесtioп, 1870.) .Wallaсе Suсh a сonсlusion Was anathеma to Darwin, Ьut hе fеlt that had good argumеnts.Natural sеlесtion unaidеd сould not produсе many distinсtivе human fеaturеs, Ьut sехual selесtion сould. Darwin arguеd that muсh that is сharaсtеristiс of humans сamе aЬout through varying standards of Ьеauty and dеsiraЬility. Hеnсе, although distinсtivе' thе fеaturеs сitеd Ьy .!Иallaсе Wеге not suсh as to tаkе mаttеrs out of thе rangе of еvolution and сеrtainly not out оf thе rangе of sсiеnсе. Thus Darwin Wrotе a long disсussion of sеxual sеlесtion in gеnеral and thеn its appliсation to humankind. 10fhyarе mеn big and strong and powеrful and intеlligеnt? Bесausе thеir anсеstorswho wеrе got thе Ьеst womеn. \7hy arе Womеn soft and yiеlding and domеstiс? Bесausе thеir anсеstors who wеrе got thе Ьеst mеn and did thе .Why ЬеstjoЬ with thе family. arе humans hairlеss? Bесausе that is whаt thеir anсеstorsfound sехually ехсiting. Why (tо gеt morе spесifiс) do Hottеntot Womеn(usingDarwin's languagе)havе suсh Ьig Ьaсksidеs?Bесausе this was thе standard of Ьеauty of thе triЬе, and thе Ьravеst Ьravеs got first сhoiсе. Еxpесtеdly,all of this is wrappеd up with somе fairly standard Viсtorian sеntimеntsabout thе rеlativеaЬilitiеs of mеn and wоmеn: ..If mеn arе сapaЬlе of dесidеd еminеnсe ovеr Womеn in many suЬjесts' thе avеrage standard of mеntalPowеr in man must Ье aЬovе that of woman'' (С. Darwin |871,2,:

З26-З27\.

jf. First visсегal sтс}t. 9. Sссond visсeгal дтсh. H. Vеrtсbгal соlumns and in рrше8{ ot dсvсloрnrt,ut. d. Antеriог l I{. Рostегiог Jеxtгenrllleз. Il. Твil trг oя сoссyx.

muвсlt:!

tan and dog. Again, Wе sее thе :ts likе thеsе,wеll known to all

No argumеnt is nееdеd to alеrt us to thе faсt that by thе 1870s Darwin and his thinking wеrе starting to sеttlе into somе fairly сonvеntional modеs. Hе may havе Ьееn a rеvolutionary, Ьut hе Was not always that far ahеad of his triЬе. It is littlе wondеr that Darwin Ьесamе a major sourсе of national pridе. By univеrsal aссlaim, whеn hе diеd, hе was Ьuriеd next to Isaaс Nеwton in that Еnglish Valhalla, Iй/еstminstеrAЬЬеy (Figurе 17).

Aftеr Darwin ly rathеr pесuliar.Most of thе Ьook :onsistsof an ехtеndеdеssay on thе :r.Thе pесuliаrityof thе topiс yiеlds Иallaсе startеd Ьy sharing Darwin's

Bеforе thе Оrigiп was puЬlishеd, еvolution rodе on thе Ьaсk of thе doсtrinе of progrеss,it was opposеd Ьy thе idеa of final сausе, and its status was akin to that of mеsmеrism and phrеnology-it was a psеudosсiеnсе. Нow did Darwin сhangе things? As far aS progrеss was сonсеrnеd, Darwin himsеlf was сеrtаinlya сultural progrеssivistand saw еvolution itsеlf as progrеssivе.

1)

z-)

24

Thе Нistorу of Еuoltttioпаrу Tbсlught

Figurе 17. Сartoon of Dаrwin as аn apе. TЬс hr-lmorwas аlw.avsgеntlе and nеvеr sаvagе. Thе Еnglish Wеrе vеr}' pr
Нowеvеr, hе аlso saw that thе link Ьеtwееn progrеss and еvolution Was somеthing that Ьrought down thе stаtus
RеmеmЬеr that as f nаtural sеlесtion spеal blind.law ехplanation foг thе еnd-diгесtеd n. thiswаs no minoг mаt thе organiс world is it Hе was Ьrought up oI sеntеd in thе сlassiс dl Thеologу (1802). Hov Darwin may havе Ьееl аny kind had no plaс plainеd without rесoul T h е s t а t u so f е v o l u t i and surprising answеr: tionary thought up to еnсе, funсtioning wit praсtitionеrs using n:rt organiс ехistеnсе and might сall a profеssio man' so thе fatе of hi Thomas Неnгy Huхlе1 in Gеrmаny. Unfortun all Ьесamе ardеrrtеvoll Оrigin, whiсh showеd gеthеr undеr thе umЬr vеry kееn on natural s that thе wholе issuе o was unnееdеd, and ot and that sеlесtion сou othеr putativе сausеs' today might саll maсr е v o l u t i o nt h r o u g h a k i Admimеdly' thеrе w' thеory. onе was thаt t sее how suffiсiеnt nеw tions that sеlесtion сor unfortunatеly Darwin thаt whеn two orgаni turеs blеnd with thosе variation, within a gе What was nееdеd was nеw fеаturеs from gе Was that on thе bаsis t ing physiсists (notaЬl suсh a lеisurеly proсе But in a way thе sсiеr

Thе Historу of Еuolutioпаrу Tbougbt

]hеhumor was alwavsgеntlеand l of Darwin, and thеy still arе. Hе is :hеn,Darwin is as muсh а part of t tЬeHornеt mаgazinе.)

]twееn progrеss and еvolution Was s of thе lattеr, and hе rеalizеd that lеniеs thе inеvitaЬility of Ьiologiсal Darwin Ьrokе thе link Ьеtwееn thе lеd that natural sеlесtionсould lеad lay's еvolutionistswould сall a kind lming from сoпlpеtition with rivals. Lnisation,thе amount of diffеrеntia3ans in еaсh Ьеing whеn adult (and Ьrain for intеllесtualpurposеs),nat;tаndard:for all physiologistsadmit сh as in this statе thеy pеrform thеir . Ьеing;and hеnсеthе aссumulation tion is within thе sссlpе of natural frоm thе third еdition of the origiп

RеmеmЬеrthat аs far аs {inаl сausе Was сonсеrnеd' Darwin thought that naturalsеlесtionspеaks to thе dеsignlikе aspесt of living Ьеings. It givеs a blind.law ехplanation: sеlесtion lеаds to adaptation, and this is thе rеаson for thе еnd-dirесtеdnaturе оf suсh fеaturеs as еyеs and hands. For Darwin this was no minor mattеr. Hе always rесognizеd that thе dеsignlikе naturе of thе оrganiс wоrld is its most distinсtivе fеaturе аnd should not Ье ignorеd. Не wаs Ьrought up On thе Argumеnt from Dеsign' еspесially as it was prеsеntеdin thе сlassiс disсussion of Arсhdеaсon \Villiam Palеy in Ьls Nаturаl Thеologу(1802). Howеvеr' what was no lеss inrportant was that although Darwin may havе Ьееn a dеist (latеr hе Ьесamе agnostiс)' for him a god of any kind had no plaсе in a sсiеntifiс ехplanation. Еvеrything must Ье ех. plainеd without rесoursе to mirасlеs or othеr spесially guidеd forms of forсе. Thе statusof еvolutionary thought raisеspartiсularly intеrеstingquеstions and surprisinganswеrs.Darwin himsеl{ wantеd to raisе the status of еvolutionary thought up to thе lеvеl of physiсs and сhеmistry-аs a maturе sсienсе, funсtiоning within univеrsitiеs and rеsеarсh сеntеrs, with skillеd praсtitionеrsusing natural sеlесtion as a toсll to сut through thе proЬlеms of organiс еxistеnсе and funсtion. Hе wantеd еvolution to Ье what Wе today might сall a profеssional sсiеnсе. But it was not to Ье. Darwin was а siсk man' so thе fatе of his idеas had to Ье еntrustеd to othеrs-followеrs likе Thomas Hеnry Huхlеy in Еngland, Asa Gray in Amеriсa, and Еrnst Haесkеl in Gеrmany.Unfortunatеly, thеy had aims othеr than thosе of Darwin. Thеy all Ьесamеardеnt еvolutionists,аnd all agrееdthat Darwin's аrgumеnt in thе Оrigin, whiсh showеd how many arеas of Ьiologiсal inquiry сould Ье tiеd togеthеrundеr thе umЬrеlla of еvolution, was dеfinitivе. But fеw, if any' wеrе vеry kееn on natural sеlесtion.No onе dеniеd it outright, but somе thought that thе wholе issuе of finаl сausе Was ovеrЬlown аnd hеnсе that sеlесtion was unnееdеd,and othеrs thought that final сausе still nееdеd еxplanation and that sеlесtionсould not really do thе joЬ. Еithеr way, pеoplе turnеd to othеr putativе сausеs' suсh аs Lamarсkism, еvolution Ьy jumps or what wе today might сall mасromutations (thе thеory is known as saltationism)' or еvolutionthrough a kind of intеrnal momеntum (orthogеnеsis). Admittеdly,thеrе wеrе somе signifiсantЬiolоgiсаl pгoЬlеms with Darwin's thеory.onе was that hе had no working thеory of hеrеdity.Pеoplе сould not sееhow suffiсiеntnеw variation сould arisе and Ье maintainеd within populations that sеlесtion сould havе a lasting еffесt (Vorzimrnеr 1970). Somеwhat unfortunatеlyDarwin сompoundеd his proЬlеms in this rеspесtЬy аssuming that whеn two organisms Ьrееd, thе usual еffесt is that thеir distinсtivе fеaturеs Ьlеnd with thosе of thеir matеs. Неnсе, if only onе has a nеw' valuaЬlе variatiоn, within a gеnеration or two it is Ьlеndеd into virtually nonЬеing. !Иhatwas nееdеdwas a ,.partiсulatе''thеory of hеrеdity,that prеsеrvеdgood nеw fеaturеs from gеnеration ro gеnеration. Anothеr proЬlеm of Darwin's Wasthat on thе Ьasis of саlсulations aЬout the agе of thе еarth madе Ьy lеading physiсists (notaЬly thе futurе Lсlrd Kеlvin), thеrе Was too littlе timе for suсh а lеisurеly proсеss аs naturаl sеlесtion to takе еffесt (Burсhfre|d |975). But in a Way thе sсiеntifiс proЬlеrns Wеrе not thе dесiding faсtor. lfhat was

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Тhе Historу of Еuolutioltаrу Thoиght signifiсant wаs that еvеn Darwin's most ardеnt followеrs wеrе gеnеrally not that intеrеstеd in turning еvolution into a profеssional sсiеnсе' at lеast not as Dаrwin еnyisioned it. This wаs thе timе of grеat fossil disсovеries in thе Nеw \world-all of thosе dinosаur rтlonstеrsof thе past-and naturally thеrе was grеat intеrеst in woгking out thе truе pаths of lifе's history (Figurе 18). In сombination with not-аltogеthеr_rеliаЬlеmеthodologiеs liftеd from еmЬryology' most famously Haесkеl's so.сallеd Ьiogеnеtiс law thаt ontogеny (thе history of thе individual) rесаpitulatеsphylogеny (thе history of thе group), muсh еffort was еxpеndеd on working out thе full dеtails of thе еvolutionаry trее of lifе. But as a сausal thеory of origins, еvolution was somеwhat of a flop. Its еnthusiаsts Wеrе сontеnt to kееp it morе аt thе lеvеl of a ..popular sсi. еnсе,'' whеrе it сould hаvе a diffеrеnt rolе. Why? By thе sесond half of thе ninеtееnth сеntlrry, mеn likе Huxlеy wеrе working haгd to Ьring thеir soсiеtiеs сrut of thе еightееnth сеntury and into thе twеntiеth (Dеsmond 7994, 1997)' Thеy triеd to геform thе military, mеdiсinе, thе сivil sеrviсе'еduсation, and othеr institutions' A strЬjесtlikе pЬysiology oЬviously hаs а pragmatiс payoff in suсh arеаs as mеdiсinе (F.igurе19).

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. . G г е а tS t i I . i g u r еl 9 . Т h е uninhaЬitаЬlеЬесаusеthс
Еvolrrtion sееms to hav Ьinеd with thе idеologу thе nеw rеfornlеd soсiс C h г i s t i a n i t v ,a k i n d o f s origins, а story of hurn they wеrе going arrd wh bаsiсаlly this wаs how l

Figurе 18. Dinosaur modеls'It wаs Riсhard owеn, in thе еаrly 1840s,who lаЬеlеda major grouр сlf rеptilеsas dinosaurs.From thе firstthеy сaptuгеd pеoplе'simaginations'as thеy still do. Thеsесonсrеtе,paintedmodеlswеrе madе foг thе Grеat ЕхhiЬition of London in 1851' whеrеBritain showеdits prowеss to thе world. Thеy arе now prеsеrvеdin а park in south London. Notе that thеy show dinosaursas rаthеrhеavy,сluпrsyЬrutеs'Tсldаy,wе think thеm muсh morе aсtivе.

rus of thе day, of whol еnсr Неrbеrt Spеnсеr. J anything from thе еigh from thе undiffеrеntiat thе homogеnеous to th thе Еarth, in thе dеvеlt Soсiеty, of Govеrnmеn aturе, sсiеnсе' Art, tl thгough suссеssivеdif]

Тhе Нistorу of Еuolutiсlпаrу Tboиgbt ardеnt followеrs wеrе gеnеrally not a profеssional sсiеnсе,at lеast not as of grеat fossil disсovеriеs in thе Nеw lf thе past-and naturally thеrе was ,aths оf lifеЪ history (Figurе 18). In mеthodologiеsliftеd from еmЬryol,iogеnеtiсlaw that ontogеny (thе hisylogеny (tlrе histоry of thе group), ut thе full dеtails of thе еvolutionary 'igins, еvolution was somеwhat of a it morе at thе lеvеl of a ..popular sсiеnth сеntury' mеn likе Huхlеy wеrе t of thе еightееnthсеntury and into iеy triеd to rеform the military, mеdrеr institutions. A suЬjесt likе physir suсh arеasas mеdiсinе (Figurе 19).

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Figurе19. Thе ..GrеatStink.''In thе suпrmеrof 1858 London Ьесаmеnеаrly uninhabitaЬlе bесausеthе Thamеs had Ьесorтеsuсh a vilе, odifеrousrесеptaсlе of еvеryonе'sraw sеwagе.Fеw things Ьrоught homе morе vividly to thе Viсtoriansthе nееdfor trainingin modеrn tесhnolоgiсalsr.rЬjесts, likе сivil (From Рuпch' 1858.) enginееring.

l owеn, in thе еarly 1840s,who rrs. From thе first thеy сapturеd e сonсrеte'paintedmodеls wеrе n 1851,whеrеBritainshowеdits ',еdin a park in south London. Notе lumsy Ьrutеs.Today, wе think thеm

Еvolution sееms to havе no suсh immеdiatе funсtion. But' еspесially сomЬinеd with thе idеology of progrеss, it сould funсtion as thе philosophy of thе nеw rеformеd soсiеty-it сould havе a rolе as а kind of altеrnаtivе to Сhгistianity,a kind of sесular rеligion in its own right. It сould Ье a story of origins,a story of humans' еxaltеd plасе in thе proсеss, a vision of whеrе thеywеrе going and what thеy should do to еnsurеsuссеssand triumph. And basiсallythis was how еvolutiс-ln Was prolnotеd, еspесiallyЬy thе lеading gurus of thе day' of whom nonе Was morе voсal than thе Еnglish man of sсiе n с еH е г Ь е r rS p е n с е r .P l а y i n g u p е v t l I u t i t l l lh, i s v i s i t l п W a s a s p r с l g r е s s i v aе s anythingfrom the еightееnthсеntury. Spеnсеr saw progrеss as Ьеing a movе from thе undiffеrеntiatеd to thе diffеrеntiatеd, or what hе сallеd a movе from thе homogеnеousto thе hеtеrogеnеous:..Whеthеrit Ье in thе dеvеlopmеntof thе Еarth, in thе dеvеlopmеntof Lifе upon its surfaсe' in tlre dеvelopment of Soсiеty,of Govеrnmеnt,of Manufaсturеs, of Сommеrсе, of Languagе, Litеraturе, Sсiеnсе,Art, this sаmе еvolution of thе simplе into thе сomplеХ' throughsuссеssivеdiffеrеntiatiсlns,holds throughout'' (Spеrrсеr1857,2_З).

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2 8 Tbe Historу of Еuolutioпаrу Тhought Еvеrything oЬеys this law. Humans arе morе сomplеx or hеtеrogеnеousthan othеr animals, Еuгopеans arе morе сomplеx or hеtеrogеnеous than savagеs' and thе Еnglish languagе is moге сomplеx oг hеtеrogеnеousthan thе tonguеs of othеr pеoplеs (Figurе 20). Inсidеntаlly, it was НеrЬеrt Spеnсеr who popularizеd thе word euolutioп, Until thе middlе of thе ninеtееnth сеntury' thе tеrm was gеnеrally rеsеrvеd for thе dеvеlopmеnt of thе individual (ontogеny). For evolution in thе mod..trаnsformation'' еrn sеnsе (phylogеny), most pеoplе usеd words likе (Riсhards 1'992). Sееing no еssеntiаl diffеrеnсе Ьеtwееn thе dеvеlopmеnt of

thе individual and thе d. just-quotеd еssay on prl tеrm for both. In thе С ..dеsсеntwith modi was ..еvolvеd.''Darwin alwa him a woolly and loosе t in the Оrigiz, a work tl tеndеd as a maior сontr usе a tеrm thаt appеaгеd to philosophy, litеratur timе of Tbe Dеscеnt of 1

day had Ьесomе univеrs and as сomfortaЬly as a A good rеligion' sесu of еvolution' thе artiсul; winism. Thе Ьasiс pattс ai

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Figurе 20. Thе trее of lifе as drawn Ьy Еrnst Haесkеl. Notiсе just how thе idеa of progrеssinfluеnсеdhis piсturе of lifе's history. (From HаeсkeL1897, 2:188.)

nеss of еvolution-sirг monаd to man. This is а vеry lеast, not impеdе i with thе еvolutionary p should promotе it and < Ьy еvolution. Start wit} nеvег oссurs-аnd it is : soсioесonomiс soсial p< pеtition, and thе wеak

supportеd amеlioration thе faсt that undеr thе r its unhеalthy' imbесilе ing,thoughwеll-mеani thе purifying proсеss br thе multipliсation of tt failing provision, and , providеnt by hеightеni ( S p е n с е r| 8 5 1 , з 2 3 _ 3 2 Christians diffеr, soI mеanings of thеir rеlig from anything еlsе, ma: world than in thе Ьiolo1 wеrе liЬеrtarian; othеrs еvolution; and still oth' appеaling to a kind оf low mеmbеrs of a spе сhism. Somе wеrе fеmi Somе wеrе paсifists (S

All usеd еvolution lеss living world-as a full-

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Thе Histсlrу of ЕuсllиtiсlпаrуThoиght for thе nеW soсiеty. No longеr:r psеudсlsсiеtlсе, еvоlutit)nwаs сегсainlyrro morе than a populаr sсiеnсе. l"{

Thе Synthеtiс Thеory Things pеrsistеdthis way into thе еarly dесасlеsof thе twепtiеth сеntuгу аnd in somе rеspесtsЬесamе еvеn worsе whеn Сontinеntal thirrkеrs,notaЬly thе еmbryologist Hans Driеsсh in Gеrmany and thе philosophеr Неnгi Bегgson in Franсе, Ьеgan pLrshinga kind of nеo-Aгistorеlianthеory of lifе thаt szrw spесiаl, nonphysiсal final forсеs guiding tlrе path of еvolution. DriеsсЬ's еntеlесhiеsаnd Bеrgson,sёlапs uitаuх' thе foundatiоns of ..vitalisпr,''wеrе iust not thе еlеmеnts of а forward-looking modеrn sсiеnсе.Rеliеf finally сamе with thе dеvеlopmеntof Mеndеliаn gеnеtiсsаnсl its mеlding rvith Darwiniurn sеlесtiorr,although еvеtrhеrе thе proсеss took til-r-rе аnd lvirs not stri]ishtforward (Рrovine |97I). Grеgor Меndеl, а Morаvian mtlпk who livеd irr thе Austro-Hungагian Еmpirе, disсovеrеdthе еssеntialprinсiplеs of hеrеdity in thе 1860s. Unlikе Darwin, hе sa'ur, thе trаnsmissionof сharасtеristiсsas ..pzlrtiсulatе,'' Ьеliеving thаt fеaturеslikе сolor аnd sizе саn Ье p.rssеdon without thе thrеat оf Ьеing Ьlеndеd аwаy (Figurе 2l ). Howеvеr, it was not Llntil thе bеginning of thе twеntiеth сеnttrrythat pеoplе сamе to аppгесiаtеthе impor. tanсе of Mеndеl's work and saw thаt it providеd а kеy еlеmеntin thе story of еvolution. You miglrt think thаt this was a tеrriЬlе missеd opportunity, and that, hаd Dагwin rеad Mеndеl's kеy papеr, hе would hllvе rеаlizеd thаt гtow hе had thе answеrs to all of tlrе issuеs of hеrеdity thаt his thеory of nаtural sеlесtion dеmandеd. Henсе, thе thеory would havе mсlvеd forward morе quiсkly' muсh еаrliеr. This is proЬaЬly not sO. Еvеn whеn thе work of Mеndеl was disсovеrеd, it to
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F i g u r е2 l . T h е p е a p l a n Меndеl to work out thе many diffеrentvariеtiе so forth. Меndеl сould passеdfrom onе gеnеfа rеsultswеге a littlе too l he was only rесordingr ovеrzеalouslytrying to plа sevеntееnth-сеntury

was rеvеalеd, and it с Finally, around 1930, taЬly R' A. Fishеr (19 Wright (19З7' t9Зz) sеlvеs and arе transmi works оnly in thе grou work to rhе соmplеtiс

Tbe Historу rlf Еuolutionаrу Тbought osсiеnсе'еvolution was сеrtainly no

dесаdеsсlf thе twеntiеthсеntury and LеnСсlntinепtalthinkеrs, notably thе 'and thе phiiosophеr Hеnri Bеrgson l-Aristotеlianthеory of lifе that saw thе path of еvolution.Driеsсh's еntfoundаtionsof ..vitalism'''wеrе just modеrn sсiеnсе.Rеliеf finally сamе еtiсsand its mеldirrgwith Darwinian s took timе and wаs not straightfora Моravian monk who livеd in thе hе еssеntialprinсiplеs of hеrеdity in rnsmissionof сharaсtеristiсsas ..parэr and sizе сan Ье passеdon without е 21). Howеvеr. it was not until thе lеoplе сamе to apprесiаtеthе imporlrovidеd a kеy еlеmеnt in the story of 's a tеrriЬlеmissеd opportunity' and lеr, hе would havе rеalizеd thаt now lf hеrеditythat his thеory of natural . would havе mсlvеd forward morе y not so. Еvеn whеn thе work of l assimilatеit. Many pеoplе at first )r than a ссlmplеment(sееЬеlow). So гhе monk's work was puЬlishеd in a ;еarсhеd,Darwin would havе found :е would havе Ьееn a ..еurеka'' m
Figurе21. Thе pеa plant.This lowly gаrdеnvеgеtаЬlеWas thе organismusеd Ьу Меndеlto wоrk out thе prinсiplеsof hеrеdity.lt wаs еasyto grow аnd сamе in manydifferеntvariеtiеsand forms-sееd аnd pod shapеand сolor, hеight'and so forth.Меndеl сould thеrеforеdistinguishаnd rесord hоw fеаturеsWеrе passеdfrom onе gеnеrationto thе nехt. It now sееmsсеrtainthat Меndеl's rеsultswеrеа littlе too good to Ье truе. It сould havе Ьееnthаt suЬсonsсiously hеwas only rесordingrеsultsthat fit his hypothеsis,or that thе gardеnеrwas ovеrzеаlously tryingto plеasеhis mastсr.This stylizеdpiсturеis from a latе. seventееnth-сеntury рlant Ьook.

was rеvеalеd,and it сould Ье sееn as thе сomplеmеnt tO natural sеlесtion. Finally,aгound 1930, a numЬеr of highly giftеd mathеmatiсal biologists,not a Ь l yR . A . F i s h е r ( 1 9 3 0 )a n d J . B . S . H а l d a n е ( \ 9 з 2 \ i n Е n g l a n d a n d S e w a l l !Иright (|9З1, I9З2) in Amеriса, showеd how Меndеlian gеnеs sort thеmsеlvеsand arе transmittеd irr groups (arrеssеntial finding, givеn that sеlесtion works only in thе group situation),and thеn it wаs possiЬlеto bring Darwin's work to thе сomplеtion that it nееdеd.Along with mutation (thе сoming of

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Тhе Historу of Еuolutionаrу Thought new variation, сausеd Ьy spontanеous сhangеs in gеnеs),nаtural sеleсtion сan truly Ье a signifiсant forсе for сhangе. Sinсе Ьy thе 1930s thе quеstion of thе agе of thе еаrth was no longеr prеss. ing (thе disсovеry of thе warming еffесts of radioасtivе dесay showеd that thе еаrth is quitе old еnor-rghfoг thе slow workings of sеlесtion),Ьiologists movеd rapidly forward with nеw idеas (known as popиlаtion genеtiсs) tЬat woцld put еmpiriсal flеsh on thе mathеmatiсal skеlеtons. In Britain a highly voсal supportеr of гhе thеoгy was Thomas Неnry Huxlеy's grandson Julian Huхlеy (thе oldеr brothеr of novеlist Aldous Huxlеy)' who produсеd a major work that pullеd idеas togеther:Еuolution: T|эe Мodеrп Sуnt|lesis(|942). Sсiеntifiсally, aftеr Fishеr thе most important figurе was thе oxford Ьiologist Е. B. Ford (|964), who did groundЬrеaking studiеs of sеlесtion in populа. tions of Ьuttеrfliеs and who gаthеrеd around himsеlf in а sсhool of ..есologi. сal gеnеtiсs''a numЬеr of youngеr rеsеarсhеrslikеwisе interеsrеdin sеlесtion and its еffесts in naturе. Notеworthy wеrе Aгthur Сain (1954) and Philip Shеppard (1958), who workеd on Ьanding pattеrns in snails, and Bernard К е t t l е w е l l1l 9 7 3 ) ' w h o s е i n t е r е s т w s е r е i n i n с l u s t r i am l еlanisnl-rhе wаys in whiсh Ьuttеrfliеs сhangе adаptivе сolor pattеrns as thеir haЬitats arе сhangеd Ьy thе еffесtsof smokе and pollLrtion.[n Amеriсa thе influеntial figurе was thе Russian-Ьorn gеnеtiсistThеodosius DoЬzhansky' whosе Geпеtics апd thе Оrigiп of Spесies |\9З7) wаs an inspiration to zrwholе gеnеrаtion of еvolu.s7orking tionists (Figurе 22). аlongsidе him wеrе othеrs' notaЬly thе oгnithologist/taхonomist Еrnst Мayr (author of Sуstemаtiсs апd the Оrigin of Spесiеs, 1942), thе palеontologist Gеorgе Gayloгd Simpson (Tеmpo апd Мodе iп Еuolutioп, 1944), and thе Ьotanist G. Lеdyard StеЬbins (Vаriаtioп апd Еuolutioп iп Plапts,1950). By thе 1950s Darwin's drеam of a maturе' profеssional sсiеnсе of еvolutionary Ьiology was rеalizеd. Мorеovеr, it was gеnuinеly Darwinian, for although thеrе had Ьееn prеtеndеrs to thе сausal thronе, notaЬly Sеwall .lfright's proсеss of gеnеtiс drift (random сhаngеs in gеnе frеquеnсy in small populаtions duе to thе vаgariеs of Ьrееding),it was гесognizеdthat thе kеy faсtor in organiс naturе is its adaptivеnеss, its manifеstation of final сausе' and thаt natural sеlесtionis a full :rnd satisfying way of еxplaining this phеnomеnon. At thе same tilтrе' proЕlress-and all thе moralizing and philosophizing that wеnt along with it-hаd Ьееn еxpеllеd.No onе was going to usе this kind of profеssional Ьiology as an ехсusе for quasi-rеligiousspесulations aЬout thе stаtus of humankind and thе oЬligations thаt naturе lays upon hum a п s ( F i g u г е2 3 ) ' Yеt, for all this, thеrе is onе morе important faсtor to thе story, and this partly еxplains why to this day еvolutionаry idеas rеmаin so сontrovеrsial to so many. Although еvolutionary Ьiology wаs upgradеd from thе lеvel of a popular sсiеnсеto thе lеvеl of a profеssional sсiеnсе,this did not oссur simply out o{ a disintеrеstеdquеst for thе truth Ьу mеn who hаd no aims Ьut thе finding of thе workings of naturе. Virtually еvеry onе of thе nеw profеssional biologists' from Fishеr to StеЬЬins,Ьесamеаn еvolutionistЬесаusеlrе was attraсtеd to thе suЬjесt Ьy thinking that it was morе than just a sсiеntifiс thеory.

Figuге 22. ThеodosiusDo fourth from left) at а сonf sсienсеmеаns having stud Hаrvard gеnеriсistRiсhаr Сornеll genеtiсistBruсе V was a Spаnishpriеst Ьеfor right in thе front row. Сlе sеxеswas а long-lastingp

For somе, likе DoЬzh: Ьгought pгogrеss-prog piсturе that saw God wс divisions that wеrе сru God's gгaсе аnd аn rrnfu was attraсtеd to thе idс ( 1 9 5 5 ) ,w h о p r o m o t е d and Мayr and Simpson too likеd thе idеa of prс somе kind of dirесtion r Bесausе all thеsе sеп еarly twеntiеth сеntury, dripping with mеtaphv surprisе if this had not h i m s е l f ,t h i s n е w l l r е е d sional status for thеir a< sсiеntists-thеn thеy wt pесts. Thеy nееdеd to d

Тhe Нistor,-oi Еuolutionаrу.[,hought 3.] эhangеsin gеnеs),natural sеlесtion е. agе of thе еarth Was no longеr press:s of radioaсtivе dесay showеd that w workings of sеlесtion),Ьiologists known as populаtiotl gепеtiсs) t,Ьat i]atiсalskеlеtons. In Britain a highly ras Flеnry Huxlеy's grandson Julian ous Huxlеy), who produсеd a major ioп: The Мodеru Sуnthesis (1,942). 'tant figurе was thе oхford Ьiologist king studiеsof sеlесtion in popula'und himsеlfin а sсhool of ..есologiсhеrs likеwisе intеrеsted in sеlесtion .еrеArthur Сain (1954) and Philip ing pattеrns in snails, and Bеrnard n industrial mеlanism-thе ways in attеrnsas thеir haЬitatsarе сhangеd -rAmеriсa thе influеntial figurе was )oЬzhansky,whosе Gепеtiсs апd tbe ion to a wholе gеnеration of еvoluhim wеrе othеrs, notaЬly thе or. or of Sуstеmаtiсsапd thе Оrigiп of гgе Gaylord Simpson (Tempo апd nist G. Lеdyard StеЬЬins(Vаriаtion

Figure22. ThесldсlsiusDoЬzhansk1''This piсturе of DoЬzhanskу froпt rrlш, fourtbfrom lеft) at a сonfеrеnсеwith his studеntsundеrlinеshow suссеssful mеanshаvingstudеntswho rvill саrry on and dеvеlоpyour idеas.Thе sсienсе HarvаrdgеnеtiсistRiсhard Lеwсlntinis sесondfrom thе lеft in thе front rсrw; lWаllaсеis riglrt Ьеhindhim; anс1FrаnсisсrlAyаlа (whсl СornеllgеnеtiсistBrr"rсе wasa SpanisЬpriеstЬеforеlrе Ьес.rпlеan Amеriсan еvolutionist)is on tlrе far rightin thе front row. Сlеarly' Dаrц,in'sviеrvson tlrе rеlаtivеaЬilitiеsсlf tЬе sехеswas a long-lastingprеjudiсеirl еvсllutionаryсirсlеs.

lturе' profеssiоnаl sсiеnсе of еvoluit was gеnuinеly Darwinian, for althе сausal thгonе, notаЬly Sеwаll r сhangеs in gеnе frеquеnсy in small ing), it was rесognizеd that thе kеy :ss, its manifеstationof final сausе' tisfying way of еxplaining this phеlnd all thе moralizing and philoson е х p е l l е dN . o onе was goingto usе сusеfor quasi-rеligiousspесulations Ьligations that lraturе lays upon hu-

For somе, likе Dobzhansky, thе i1ttrz1сtionwаs ехpliсitly rеligious. Не ЬroughtpгogГеss-progrеssto httmаns,that is-inttl a kind of ovеrirll world piсturеthat saw God working his way through thе foгсеsof nаturе. Ignoring divisions that wеrе сruсial to еarliеr thinkеrs, DoЬzhansky thought that God,sgraсеand irn unfrrrlingсrеаtion сould Ье сomЬinеd. Unsurpгisingly, hе was attraсtеdto thе idеas of thе .[еsuitpalеontolсlgistTеilhard dе Сhаrdin Huхlеv in Еngland (1955),who pronrсltеdsimitаr idеas. Othегs, likе .[r.rliаrr and Мayr and Simpson in Amегiсa, wеrе sесцlal.iп thеir thinking, Ьtrt thеy too likеd thе idеa of progrеss and thought that it showеd thаt еvolutitln had

)ortant faсtor to thе story' and this ary idеas rеmain so сontrovеrsiаl to , was upgradеd from tlrе lеvеl of а > n a ls с i е n с еt,h i s d i d n o t o с с u r s i m LthЬy mеn who had no aims Ьut thе ly еvеry onе of thе nеw profеssional tе an еvolutiоnist bесausе hе was at'as morе than just a sсiеntifiс thеory.

somеkind of dirесtiсlnand mеаning. Bесausеall thеsе sеminal еvolutiоnists wеrе pеoplе whо grеw up irr thе еarlytwеntiеthсеntr.lry,whеn rnuсlr uldhavе Ьееn a surprisеif this Ьad not Ьееn tЬе lnаin motivating fасtсlr. But' likе Darwin saw that if thеy wеrе to havе profеshimsеlf,this nеrv Ьrееd of еvolr"rtionists sionalstatusfor thеir асtivitiеs-soп1еthingthеy аrdеntly dеsirеd as full-timе sсiеntists-thеnthеy would nееd ttl purify thеir work Of its ехtrasсiеntifiсaspесts.Thеy nееdеdto dеal witlr dсlсrrinеsof prсlgrеss:rnd with еХtгapolаtеd

34

Тhе Historу of Еuolutionаrу Thought

STUDIЕS oi\ IltliADIATЕD POPULAT]ONS D no So P Н I I, А M l] I' А N oG А S1,]tr]l*

oI..

By BRUCE WALLAс]] Bio|фc,ot I,a|пralorу,CoIdSqriщ llа'rbor, N.Y. (With Fivе Teхt.figures) (Recеiod 28 Jdу |95б) rштвoоuстloш It iв well kпorтn thаt the тridеspгead use of ionizing гвdiations, beсsuse of tlrеiг gеnetiс effeсts, posoв в pгoЬlem futurе genегations. The*е гadiвtions induсe gene .""g""diog mutations. TЬe vast majority of mutвtions haie dеletегiousеffесtson individuals свгrying them. Undег the pгеssuгe of сontinued mutatiоn, thеse deleteгious mutationв will aосumulatе in populвtionв. Thereforе, an iтгadiated population will, on thе avеrage, be lцrmеd-havе its .fitnesв' reduced'-by a сontinual u*р.o." to irгadiation. The pгеsеnt aгtiсle вummarizев obsrгvдtions made on iгrаdiatвd po|oйi1"". oi lиo. so1lhilamе|юnчавtюr.Somе of thе.mвterial presentedteгe haв Ьееn p"ьri'ьa pгeviously (Wallaсе, 1950, lg5l; wl]tryе & King, l95i, 1952). This summвгy,^ho,n".'',u., will intro. duсe lrew mдtоrial in вddition to еxtйding the oгiginai obsеrvatiЬns. Мдтввlдr, AND DtEтЕoDs Thе erpет'imеntnlnop]nlion.s. Tire eхpетimental population в of D' mеIюn,чoslerarе kept in luсite and sсгееnсageв.The огiginal fliев *eгe oЪйinеd fгom an oгчoniR stгвin kept' lry mass tгвnsfеr for mвny yearв. Fouгtеen letЬal. and sеmi.letЬвl-fгee sесond сhгomosomes wеге extrвсted fгom thig.stгвin thгough the usе of a вeriевof matings identiсal to tJrовedesсribed later (Fig. 2.)'.Flies сaгrying thеsе sесond сhгomosomes and miхtures of orеgon.R and .markеd stoоk' сhromosomeвotheг than thе ..""od ;;;; йlarental fliеs оf thс populвtions. Rгief dевсriptions of thе рpulationв aге given in Tаblе 1. Thе left-hand сolumn gives thе identifying numbег foг eaсh populвtion. Thе весondсolumn indiсateв tircoгrgin of thо .Stoоkв'indiоatеs populations whoвеoгiginal flies сaтгiedluth'l.г."u рopulation. *uсond сhгomosomes of oregon-R. deгivation. Tlrтeе more rеоent populations aгe subpopulations оf populationв 5 вnd 6; the deвignation in the tablе gives tie^pвгent,r p"p"ьt,l"" and the gеnегation duгing whiеh eggs wеIе removеd to вtaгt tЬе nеw The tЬird р"p'i*;;;. сolumn indiсвtеs the numlrег.ofвdulЬ in thе population .Ь,gu' .uiu.* to popotu. ".g"*, tions of aliout ]0,000 indir'iduals,.small'fo рpulвtionsЪ"qo"oТly *]iti гu'u. tь"n 1000 ildividuals. Thе last thгee сolumns of TaБlе l givе thЁ typJ ot."*po*uге, the
Figurе 23. A papеr on fruit fliеs Ьy Bruсе \Х/allaсe.Sее thе aсknowlеdgmеnt at thе^bottomof thе pagе. By thе 1950s' evсllutionistswеrе Ьесomi.'g u.iy сrеativе at finding funds for thеir work. DoЬzЬаnsky pеrsuadеdthe U.S. Aiomiс Еnеrgy Сommission that fruit fliеs wеге thе pеrfeсtmodеl organism for studyof the effeсtsof nuсlеаr rаdiation, a majсlr worry at thе timе givеn thе o.'goi.,g tеstlng of ЬomЬs (in.thеatmosphеrе). In Еnglanj, Е. B. Fоrd fеrsuadеdthБ шurя"ld Foundation that thе study of Ьuttеrfliеsgavе insight inio thе sprеad of gеnеsin populаtionsаnd hеnсewas of grеatvaluе in studyinghuman gеnеtiсallv саused аilmеnts.

moral ехhortations. so 1 Progrеss' morality, and l duсеd as profеssional rеs foundеd journal Еuolutiс authors' dеpositеd with t ing aЬout his intеntions l еnсеs аs possiЬlе. On tЬ ..Thе fiеld hаs rеaсhed Also, еvolutionary rеsеa from thе phylogеnеtiс ir еvaluаting thе faсtors of on thе othеr hand, it ha sеаrсh has suffеrеd in thl tion'' (lеttеr to G. G. Fеr Yеt, having donе thеir tionists thеn wrotе othеr еxhortаtion as anything 1 rrсtivеs wеrе foсusеd on l ninеtеenth. ..Thе most еs Ье just this: knowlеdgе' t As a first proposition of еvolution, it is suЬmittеd aсquisition of nеw truths ly the mutations of thе n. to othеrs and Ьy thеir aс< ity)'' (Simpson 1949, З1 Stаlinism was at its pеal undеr thrеat Ьесausе of t surprisingly, thеrеforе, .. and undеr somе сurrеnt ( ogy whiсh сan Ье madе t< of еthiсs hеrе maintainеd

Thе Past Half Сеntt

That was all 50 or morе synthеtiс thеorists in Am sidеrеd just as a sсiеnсе, thеory dеsеrvеdly is onе еmpiriсаl inquiгy. Еvery flourishеs as nеvеr Ьеfort еmpiriсal, havе rеaсhеd Rosеmary and Pеtеr Gral paradigmatiс еxamplе of hаs Ьееn vеry imoortant ]

сD PoPULAT]olt,s ol. LАNoGАS1,Eht* rALLАcli фniщ llarbor, N'Y. кt.figureв) uJу |9bб) ,тIoN

nizing radiations, bесause of t}reiг genetiс nегвtionв. TЬese гвdiвtions induсi gene l delеtегiouвеffeсtson individu"l. ."..}ьg ,tвtion, thеsе delеteriouв mutations wil.i tiвtod рpulation will, on the avеrвge, Ь ;inual ехрвuге to iггдdiвtion. r mдd-e. on iггвdiдted populations of Drosentedheгеlrвв bеen puЬlished pгеviously 952)'Thiв summвгy, howeveг,will intro. е oгiginвl obsеrvations. }lEтвoD8

tal populationвot D' mеlл,nчasler aге kept

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::lb*iid 1n iial- and sеmi.lethвl-fгee seсond the use of a seгieвof mвtings identiсвl "h.on,Ьtо resевесondсhromosomesand miхtuгes of heтthgn thе вeеondrveгethe paгеntal flies

эn in Tablе l. Thе left.hand сolumn gil,es e seсondсolumn indiсates tй" o.lgi,, #tьu rвe original flies сaггied lethal.frer seсoпj oJe recrnt poрulationsaгe вubpopulations вbIеgivesthе pвтеntalpopulation and thе .o ..11' tbе nеw р
/allaсе.Sееthе aсknowlеdgmentat riсlnistswеrе Ьесominguеiy сгеarivе ,,pеrsuadеdthе U.S. Atomiс Еnеrgy modеl organismfor study of thе ...i'.. givеnthe ongoingгеsring l. f :. б. l.ord pеrsпаdеdrhе Nuf6еld : insightinto thе spreаd of яеnеsin s г u d y i n gh u m a ng е n е t i с a l Iсyа u s е d

Tbе Нistorу
Thе Past Half Сеntury Тhаt wаs all 50 oг morе yеars ago. Thе nеo.Darwinians in Britain and thе synthеtiсthеoristsin Аmеriса Ьuilt good foundations for thеir sсiеnсе.Сonsidеrеdjust as a sсiеnсе,whiсli it h,. .u..y right to Ье, modеrn еvoluttonary thеorydеsеrvеdlyis onе of thе most fo,-n,j-looking and е*сitinf аrеas of еmpiriсal inquiry. Еvеry onе of thе аrеаs trеatеd Ьy Dаrwin in t|te Оrigin flourishеsas nеvеr Ьеforе.Sеlесtion studiеs thеmsеlvеs,Ьoth thеorеtiсаl and еmpiriсal' havе геaсhed a УerУ high dеgreе of sophistiсation. The work of Rosеmaryand Pеtеr Grant (1989) on thе Ьеak sizе of Gal5pagos finсhеs is a paradigmatiсехаmplе of ехсеllеnt sсiеnсе.Тhе аdvеrrtof -oГ...'ln. biology has Ьееnvеry important hеrе for offеring Ьotl-rnеw insights (for instanсе, thе

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Figlrе 24. Thе сovеr of thе first issuе сlf Еuсllиtir.пt. onе сlf thе ЬiggеstprсrЬlеms of thеsееarly profеssionalеvolutionistswas of findingpеoplе,working to thеir standards,who wеrе nоt studyingfruit fliеsor similar organisrns.Thе journal was launсhеdwith а gгаntfrom thе Amеriсаn PЬilosophiсalSoсiеty(fсlundеdЬy BenjaminFranklin) in PЬilаdеlphia.Rеvеаlingly,tЬе only pеrsonOn thе grxnts сommittееwho opposеdthе fundingWаs thе еmЬryologistЕdwin Сonklin. ЕmЬryologyWas thеn thе quееnof thе Ьiсllogiсalsсiеrrсеs and Сonklin was not сonvinсеdthаt еvolutionсor-rldЬе thе Ьasisof rсal profеssionirlsсiеnсе.Pеrhaps bесausеоf thеsеdisсiplinarytеnsions,еvolutionistsrеspсlndеdЬv ignorrng Ьiology еmbryologyand it was not until thе 1980s,Ьy wЬiсh timс m
signifiсanсеof drift at thе nеtiс fingеrprinting for dс .W dеtailеd in Еdward o. Sуnthеsis (1975), havе po tion and rесiproсаlaItrui t o е х p l a i n t h е i n t г i с a с i е sl from an individualistiс pе е m p i r i с а ls t u d i е s - f o r i n s t (|982) on thе rеd dееr of S a powеrful faсtor in thе е sially, thе fiеld (oftеn hеrе Darwinian fаshion looks ' fantiсidе and sехual Ьеha tion. Pаlеontology has Ьt major fossil finds-rесеntl twееn fish and amphiЬial mеntion thе finding in Ind srs, naturally known as tJ tесhniquеs havе еnaЬlеd g еvеr gгеаtеr pгесision. At pгoposеd (for instanсе, th аnd thе lаtе Stеphеn Jay othеr arеas of еvolutionar t е r n so f t h е p а s t ( f o r i n s t а | | 9 7 6 | u s е d е с o l o g i с a lt h t pаst pаttеrns of animal с сhangе, an еvеnt that oсс

Figure25. Punсtuatеdеqu g r a d u a l i s m .Ь. у Е l d г е d g еi r а l t е r n а t i v еp i с r u г е( B ) ' i t g l sаltationist,whiсh rathеr s сomparativеtimеsсalеs.Fс сhangесan tаkе plасе duri Ьarеlygеts rесordеdand a

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I F'uolutiсlп. Orrеof thе ЬiggеstprtlЬlеn.rs working to thеir was of findingpеo1rlе' Thе journal fliеsor sinli]arorganisгrts. lеriсanPhilosophiсаlSoсiеty(fсlundеdЬy vеalingly,thе оnly pеrsol-lon thе grants аs thе еmЬryologistЕdrvirlСonklin. ЬiologiсаlsсiеnсеsanсjСtlnklin Was not lasisof rеal profеssionаlsсiеnсе.Pеrhaps . v o l u t i о n i s rt еs s р t l l l d еhdv i g n о г i n g 80s' Ьy whiсh timе molесr-rlаr Ьiolсlg1, that it agаinЬесzrmе а lnajсlrсlепrеntin

Morphology

|v]orphoIogу

Figurе25. PuпсtuatеdеquiliЬriurn.lrr thе Dаrrviniаnpiсturе,lаЬеlеd..phуlеtiс grаdualism,' Ьy Еldrеdgеаnd Gсluld (A), еvolutiongoеs smoothly.in thеrr piсture(B),it goеsЬy jumps. Gould dеniеdstronglythat hе was a alteгnаtivе whiсh rathеrsuggеststhat muсl-rof thе dеЬаtеwas aЬout saltationist, For а fгuit fly gеnеtiсist,1,000 1'еаrsis an agе аnd muсh соmparаtivе timеsсаlеs. 1,000 yеars сhаngесan takеplaсеduring thаt pеriod.For a pа[еoIltologist, Ьarеlvgеtsгесordеdаnd any сhаngеsarе gоing t()sееnlinstintanеOlls.

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Anteaters Armаdi||os Capybaras Glyptodonts Monkeys Opossums Porсupines

Figurе 27. Pаttеrns of foss y o u a s s u m еr h а t t h е с o n t i г how muсh еvolutioniststo wе hаvе сome from thе ol

Phorusrhaсids Bears

Sloths

Camels

Тouсans

Cats

Тoxodonts

Dogs EIephаnts Horses Peсcaries Rаbbits Raссoons Skunks Тapirs Weаse!s Figurе 26. Тlrе Grеat Amеriсаn Intеrсhаngе. By trеating North Arrrеriса and Sсluth Arrlеriса аs if thеy wеrе t''vо islands Ьеing сolonizеd, onе сan rvork out thе ехpесtесl гаtеs сli ехсlr.lпgс anсl thс numЬеrs tlf invadirrg gr.ouPs сlnе wсluld Ii Ьrium. ехpесt at еqr"ri

Systеmatiсs has bееn tran thе сoming of сomputеrs absorbеd, quantifiеd, сal likеwisе is opеn to nеw u! thе synthеtiс thеorists tе oame euolutioпаrу det,el сеptual baсkwatеr to thе еvolutionary studiеs (Сar

instаnсе,aЬout thе ways mans sharе thе samе un thе ways in whiсh orgс among thе hottеst arеas ( Thеrе arе' of сoursе' с thе importаngg-1hg ygr

еvolutionists' partiсularl; s o m е t i m е sq u е s t i o n s o f .

Thе Historу of Еuсllutioпаrу Tbought )vеdnorth to south and south to north rеoriеsof gеographiсdistribution Wеrе есtoniсs.Until this point, in a tгadition еvolutionistshad spеnt many happy lridgеsand finding ways in whiсh sееds эdiеs of watеr. Now thе moving of thе Lystrosaurus,a mammal-likе hеrЬivo00 million ),еarsago' is fat, short, and t would havе гoamеd far and widе. To. i г s( L o w е rT r i a s s i с )o n t h е с ( ) n t i n е n гos f l. This would Ье inехpliсablе wеrе it not l yеars ago аll thоsе сontinеnts touсhеd ly havе sinсе driftеd apart (Figure 27). Antаrctiса

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Figurе27. Pattеrnsof fossil organisms.ThеsеdistriЬutionsmakе sеnsеonly if youassumеthat thе сontinеntswеrе joinеd. Phеnomеnalikе thеsеshow jusr howmuсhеvolutioniststoday still work in thе Darwinian modе аnd yеt how far we havесomе from tЬe Оrigiп itsеlf. (Unitеd StatеsGеologiсal Survеy.)

Phorusrhaсids Sloths Touсans Тoxodonts

аngе.By trеating North Amеriсa and rds Ьеing сolonizеd, onе сan wсlrk out numЬеrs of invаding groups onе would

Systеmatiсs has Ьееn trаnsformеd Ьy nеw сladistiс tесhniquеs,muсh aidеd Ьy thе сoming of сomputеrs that hаvе allowеd massivе amounts of data to Ье aЬsorЬеd,quantifiеd,сalсulatеd, and undеrstood (Hull 1988). Мoгphology likеwisеis opеn to nеW undеrstandings.AЬovе all' еmЬryology' a suЬjесtthat thе synthetiсthеorists tеndеd to ignorе, has now, еspесiaily undеr thе nеw nameеuolutiсlпаrуdeuеlopmепt (evo-dеvo), Ьееn сonvеrtеd from a nonсon. сеptualЬaсkwatеrto thе most еxсiting arеа of rеsеarсhtoday in thе fiеld of еvolutionarystudiеs(Сarroll 2005). Fantаstiс nеw findings havе еmеrgеd,for instanсе, aЬout thе ways in whiсh organisms аs divеrsе as fruit fliеs and humans sharе thе samе undеrlying gеnetiс mесhanisms for dеvеlopmеnt, and thе ways in whiсh organisms arе Ьuilt and vаriations arе produсеd arе amongthе hottеst arеas of rеsеarсh (Figurеs 28 and 29). Thеrеarе, of сoursе, сontrovеrsiеsand diffеrеnсеs.No onе wants to deny thе importanсе-thе vеry grеаt importаnсе-of natural sеlесtion.But somе partiсularly in arеas likе palеontology and еmЬryology, whеrе еvolutionists, quеstionsof adaptivе signifiсanсеarе (as was еarliеr thе сasе for somеtimеs

39

40

Tbе Historу of Еuolutiсlnаrу Thrlught

pеoplе likе Thomas Hеnr. pеrhaps othеr сausal faсtс of thе thеory of punсtuatе many fеaturеs arе not рal that is, nonfunсtional byL е w o n t i n l 9 7 9 ) ( F i g u r е s. ..Just rеlying tоo oftеn on yard Kipling (Figurе 32).

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Figurе 28. Dеvеlopmеnt in thе fruit fly. In thе сеntеr Wе hаvе thе gеnеs that сontrol dеvеlсlpmеnt, in thе ordеr in whiсh thеy Oссur on thе сhromosomе. Bеlсlw wе havе thе lаrvа and aЬovе wе hаvе thе grown fly.

L|vn{d P K в o в т A Y | в H o I L Е L L K I - F н Y | \ R Y L l в п н в } . е t д н t t V L s Е в o U K I W F o N в п м к wKкLкPф\ т К N v R т K в s в т A Y т в o o V L Е L Е K Е l H F N в Y L т п п в н t ! : в t д н s r с r т Е в o I K l W l o N R R M K W K K D йR$L P N l к т в s дi."iiн."д к LDPl .Nl т K | в s PKRsRIAYтRoovLtLFKЕFнYNвYLтRвRRVLIAF{ALсLsLRoIKIWFoNJRвMKWKK м^i'."н.,вд t R o I K I W F o N в R M К W K K DKнL P N т K I R s н " й l " н . ^ Ъ q P K R s R т A Y . l R o o V L Е L L к Е F н Y ' \ ] R Y L t п в я в v в tслLфs Е KKL D PN P K в s в т A Y т в o o v L F L Е K Е t t ] Y l \ R Y L т в R R в v F I A н s L с L s t R o l K I W l o N в R M K W K н тKIRs сhtсkHoхB4 KKH Lк PD\нт к | * s ;;;;;";;; f. fЁKкввss в т A l вRRRRRвVVEЕI A | Aн нт LI Lс Lf fsLEsRЕoвI oK Il W K IFW FR oN в RK М д vYтI ввoooovVLLЕЕLLЕtKKЕEFFнHYYNNR вY YL тL R oN RM WKK W KD K L P N тKVвS i'.],u"'Ъo KLPNтKцю] )lЁi"?i'ьi.Ъ"* miisЗщvтвooY!ELЕKЕFнYIIцLIRпвпvвtnнтrtllrsввqIKIWFoNRRМKWK!qц

F.igurе29. Homologous amino aсids.On thе lеft is а сolumn tlf thе nаmеsof gеnеsin diffеrеntоrganisms.All of thеsеgеnеsarе сruсial,kiсking in at similar stagеsof dеvеlopmеnt.Thе rows irr thс main Ьoх irrеmadе up of lеttеrs сorrеspondingto amino асids,produсеdЬy thеsеgеnеs,in turn produсinga vital protеin.It саn Ье sееnthat thе gеnеsof frrritfliеsand humans arе virtually idеntiсal,lеаdingto thе сonсlusiоnthаt dеvеlopmеntis likе Ьuildingmodеls with l,еgo Ьriсks.You startwith thе samе piесеsand thеn put thеm togеthеrin vеry diffеrеnt Ways.

Figure З0. A spandrel froп and assistants.Gould's сla spаndrеls(асtually,thе tru sРаndrеlssееm dеsignеdfс rеsultof othеr nееds.Hеn< p е r h а p sn a t u r а ls е | е с t i o ri

Тhe Historу сli l:,uсllиtioпаrуThought pеoplеlikе Thomas Неnry Huхlеy) not ovеrwhеlmingly prеssing' think that pеrhapsothеr сausаl faсtors wеrе sigrrifiсant.This Was thе undеrlying thеmе of thе thеoryof punсtuatеdеquiliЬri;r,with Gould in partiсr.rlararguing that manyfеatuгеsаrе not pагtiсLllarlyadаptivе Ьut arе moге ..spandrеl-likе''that is, nonfunсtional Ьy-prоduсts of thе еvolutionаry proсеss (Gould аnd Lеwontin1979) (Figurеs30 and 31). Hе aссusеd Darwinian еvolutionists of rеlyingtoo oftеn on ..Just so'' storiеs' thе fantaЬulous.likе talеs told Ьy Rudyard Kipling (Figurе 32). Today many еvo-dеvo еnthllsiasts fееl muсh thе

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[n thе сеntеr \4,еЬаvе thе gеnеs thаt iсh thеу ()ссur On thе сhromсlsomе. tаvе thе gгorvn flv.

вфr днтivGйoUKIWI oNRвMкWккф кrешткг.tvв B q f ж jЕA F l s L G Lт Е R o I K I W F oN R в M к W к к D i s R L P N т K т R s в в V Е|A l - s L с L s t п o I K I W F o \ в R M K W к K D H K L P N I K | в s R в V EI A | - f f L с L s Е п IoK I W lo N в R M K W K к D H к L P N т K | в s R я V Е |A H S L с L s Е R o IK I W F o N R R MK W K K D H к L P N т K I R s п в v в t n н т ф r s с п o l K l w t o N R R М K W к к o н к t .в t , ' l т кt s $ R R v t I А Hт L с L s Е R o| к | W F o NR R | vK]W K K D H K t P N т K V R s R B Y q l4 ! . г ф ц s Е R o I K I W t o N R R М K W ц ц q н ]щ L р ш т к ф .

n thе lеft is a сolumn of thе namеsof 3 gеnеsarе сгttсiаl,kiсking in аt sirrlill.rr main Ьoх arе madе up of lеttеrs l Ьy thеsеgеrrеs,in turn prtldr-rсing a rs of fluit fliеsаnd humans аrе r'irtually is likе Ьuilding moс1еls dеvеlopmеnt 1еpiесеsand thеn put thеm togеthеrin

FigurеЗ0. A spandrеlfrom thе Villа lr:rrrrеsinа in Romе, pаintеd Ьy Raphaеl аndassistants. Gould's сlаim is thаt rrrаnyfеаturеsof organismsarе likе (aсtuzrlly, spandгеls thе truе tесhniсаlnamе is pеndеntivе).Although thеsе spandrеlssееmdеsignеdfor painting' in truth thеy аrе siпrply produсеd as thе rеsultof othеrnееds.Hеnсе, onе shсlr-rld not аlways look for adaptation and pеrhaps naturalsеlесtiсln is ovеrratеd.

41

42

Тhе Historу of Еuolиtioпаrу Тhought

Figuге32. Thе elephant's nosе сamе aЬout Ьесausе, that many storiеsaЬout a<

Figurе 31. Thе Irish еlk. Aсtually, this now-ехtinсtЬеast,found in thе Ьogs of Ireland,is not a truе еlk. lt is rеmarkaЬlеfor its antlеrs.Thеy arе so largе it is hard to imaginе that thеy сould еvеr havе Ьееn of adaptivе аdvantagе.A popu. lar hypothеsistoday is that thеy grеWthrough sехualsеlесtion'thе еlks with Ьiggеr horns dеfеatingthеir rivаls and gеtting thе fеmalеs.It is suggеstеdthat thе еlks Ьесаmеfеrtilе Ьеforе thеy stoppеd growing and pеrhaps аn immаturе еlk would pass on his gеnеs,еvеnthough latеr in lifе hе and his offspringwould Ье at a disadvantаgе. An еxplanationlikе this shows how сarеfulonе should Ье in tаlking aЬout adaptationаnd its aЬsеnсе.In onе sеnsе,thе аntlеrsarе аdaptivе,but not nесеssarilyfor survivaland pеrhapsnot for muсh of thе animal'slifе.

samе way. ..Thе homologiеs of proсеss within morphogеnеtiс fiеlds providе somе of thе Ьеst еvidеnсеfor еvolution-just as skеlеtal and organ homologiеs did еarliеr. Thus, thе еvidеnсеfor еvolutiсlnis Ьеttеrthan еvеr. Thе rolе of natural sеlесtion in еvolution' howеvеr, is sееn to play lеss an important rolе. It is mеrеly a filtеr for unsuссеssful morphologiеs gеnеratеd Ьy dеvеlop. mеnt. Population gеnеtiсsis dеstinеdto сhangе if it is not to Ьесomе as irrеlеvant to еvolution as Nеwtonian mесhaniсs is to сontеmDorarv ohvsiсs''

(Gilbеrtet a|. 1996, З68, likе thеsе arе wisе and p, asts for a nеW disсiplinе way' thе vigor and еxсir firmеd. Doеs this thеn mеan tl tionary thinking has nor many pеoplеas a kind ol numЬегs of artiсlеs and grams) show oг justify i еvolution. Еdward o. W of books dеsignеd to sh flows not iust moral ех} forеsts-Ьut an aItеrnati

But makе no mistakе еnts thе human mind v wаys, point foг point i narrativе form is thе е1

Тbе lIistorу of Еt,сllutiсlпаrуТhoиght

Figurе32. Thе еlеpЬant'snosе.In his stсlriеs,Kipling сlaimеdthаt thе еlеphаnt's nosесamеaЬoutЬесausеа сroссldilеgraЬЬеdit and pullеd. Gould suggеstеd thatmanystoriеsaЬout adaptivеadvantagеhavе аЬout аs muсh plausiЬility.

)w-ехtinсtЬеast,found in thе Ьogs of э for its antlеrs.Thеy arе so largе it is 'е Ьееnof adaptivеadvantagе.A popu' roughsеxualsеlесtion,thе еlks with )ttingthе fеmаlеs.It is suggеstеdthat е d g r o w i n gа n d p е r h a p sа n i m m a t u r е r later in life hе and his offspring would е this showshow сarеfulonе should bе rсе. In onе sеnsе'thе antlеrs аrе I and pеrhapsnot for muсh of thе

;s within morphogеnеtiс fiеlds providе n-just as skеlеtaland organ homoloеvolution is Ьеttеr than еvеr. Thе rolе е v е r ,i s s е е nt O p l a y l е s s a n i m P o r t а n t пl morphologiеsgеnеratеdЬy dеvеlopo сhangе if it is not to Ьесomе as irrеl:сhaniсsis to сontеmporary physiсs''

(GilЬеrtet a|. |996,368). No douЬt postеrity will tеll us whеthеr sеntimеnts likе thеsеarе wisе and prеsсiеntor mеrеly thе unjustifiеdеffluvia of еnthusiastsfor a nеw disсiplinе thаt is trying to еstaЬlish itsеlf as important. Еithеr way' thе vigor and ехсitеmеntof сontеmporaгy еvolutionаry thеory arе сonfiгmеd. Doеs this thеn mеan that thе nonsсiеntifiс'morе idеologiсal sidе to еvolutionarythinking has now vanishеd? Doеs еvolution nо longеr funсtion for manypеoplеas a kind сlf sесular rеligion? Not at all. on thе сlnе hand, hugе numЬеrsof artiсlеs and Ьoсlks (not to mеntion radio and tеlеvision programs)show or justify idеologiсal impliсations аsсriЬеd to or drawn from .Wilson is а paradigm, for hе has pourеd out a strеam еvolution.Еdward o. of Ьooks dеsignеdto show that еvolution is progrеssivе аnd that from this .Wilson' thе prеsеrvation of thе rаin flowsnot just mоral ехhortations-for forеsts-Ьutаn altеrnativеviеw of сrеation to that of trаditiona1rеligion: But makе no mistakе aЬout thе power of sсiеntifiсmatеrialism. It prеsеntsthе human mind with an altеrnativе mythology that until now has always,point for point in zonеs of сonfliсt, dеfеatеd traditionаl rеligion. Its narrativеform is thе еpiс: thе еvolution of thе univеrsе from thе Ьig Ьang

4З

Г 11

Тhс Нistrlrуrlf Еuоlutitlпа1'Tbought сlf fiftееn Ьillion \Iеаrsago thrсlugh thе origin of thе еlеrrrеntsand сеlеstial Ьodiеs to thе Ьеgir.rnings of lifе on еartlr. Thе еv
10,000 yеaгs old and that i еrgy in just six days' follor vеrsal flood' savе only for (Rusе 2005; NumЬеrs 20( story hеrе' Ьut thе сonstan еnthusiastsfor this kind of thеory Ьut as somеthing m. tionаl Ьеliеf systеms that с hеld morаl norms. In thе' ..It rаl is Hеnry М. Мorris: punishmеnt for murdеr аn mеnt for othеr sеriousсril е v o l u t i o n а r yd е t е r m i n i s mt гis 1989, 148). Appаrеntl ..ath Rusе,'' а wеll_known thе morаl rot. lvlorе rесеn has morphеd into thе morr gеnt Dеsign Thеory, whiсh q u i r е s p е с i a lс r е a t i v еi n t е r is morе than just a сonfliс pеting idеologiеs. Thе fou Bеrkеlеу law profеssor Ph о l d t е r m s :. . T h е C h г i s t i а n an еasy targеt Ьесatrsе it ] with worldly idеаs likе hul whiсh аrе aсtually profoun ingly, this humanistiс mеt: gay marгiagе, aЬortion, ar

Conсlusion

Тhе history of еvolutiona until 1859, it was littlе m. idеology of progrеss, thе r It was opposеd to traditiol litеral truth of thе BiЬlе Ьl that сhangе сomеs only t on thе Оrigin of Spесiеs ,

truth of еvolution onсе an tion was ignorеd or down Darwin, notaЬly Thomаs еvolutionary idеas as a ki аn altеrnativе idеology to to soсiаl rеform. Thе thir. of Меndеliаn gеnеtiсs. I

Thе Нistorу of Еuolиtioпаrу,Thought tlrе origin of thе еlеrrrеntsаnd сеlеsе on еarth. Thе еvolutiсlrraryеpiс is ws it аdduсеs hеrе аnd nсtw arе Ьеy provеd ttl form a сausе.irnd-еffесt сial sсiеnсеs,from this woгld to аll :, and Ьасkward througЬ tinlе to thе lart of ехistеt-lсе is сonsidеrеd ttl Ье I1O ехtеrnal сontr
s kind of spесulatiоr-r-zrltl-rough hе disrrrсlwantеd to suЬstitшtеlris own idеаs s StерhеnJay Gould, partiсularly in his puЬlishеd mсlnthly in |хJаturаlHistorу. :rеkind of moral mеssagеfrсlm his writLiсin our soсiеtyсlr thе nеес]for сonsеrnal rеligiсlnmuсh morе sсopе than did Lеf:rvorеdсhiidrеn of Goсl, thаt wе lrurеation' arе simply hLrЬris...Sinсе dirrkedly largеr Ьrains, and sinсе suсh a iеs of rеptilian dеsign , We tnust asvе еvolvеdon our planеt if а сosmiс сasaurs as viсtims. In an еntirеly litеral аnd rеastlningmamtnаls, to our luсky J antiсipаtесlthе so-саllеdllеW аthеists' г h с r е а l m o f p o p u l : r rs с i е n с е w г i t i n g . tsitm(2О06)Dawkins argLlеsthat Сhrist)r sourсеsof humankind's rlls, and that )stitutе-a sесular philosophy informеd akеs appеalsto traditional rеligions not lsophегDaniеl Dеnnеtt's I)опuiп's Dапrr of tЬis kind of litеraturс' 'ny сгitiсs of еvolr.rtiorr:rry thinking. In rrfiгmsthat most Amеriсans do not ЬеrjorityЬеliеvеthat thе еi.rгthis lеss than

10,000yеars old and that all organisms wеrе сгеatеdin а Ьurst of divinе еn. еrgyin just siх dirys, followеd somе timе latеr Ьy thеir dеstruсtion in a цnivеrsalflood, savе only for thosе luсky pairs that floatеd away in Noah's ark (Rusе2005; NumЬеrs 2006|. Amегiсan еvangеliсal Сhristianity is not our storyhеrе,Ьut thе сonstant attасks on modегn Darwinism show сlеarly that for this kirrd of rеligion do not rеgard еvolution as just а sсiеntifiс еnthusiasts thеoryЬut as somеthing пlorе' a mаtеrialistiс,sесular altеrnаtivеto thе traditionalЬеliеf systеlllsthat сarriеs lvithirr it opposition to аll dесеnt and long..сrеation sсiеntist,'' hеldmoral norms. [n thе words of thе lеаding thе latе ..It HеnryМ. Morris: is rathеr oЬvious that thе modеrn opposition to сapital punishmеntfor murdеr аnd thе gеnеral tеndеnсy towаrd lеniеnсy in punishmеntfor othеr sеrious сrimеs аrе dirесtly rеlatеd to thе strong еmphasis on еvolutionarydеtеrminismthat has сhaгaсtеrizеdmuсh of this сеntury'' (Mor..notorious Dirrwinian philosopЬег Miсhaеl ris 1989, 148). Apparеntlv' thе ..athеistiс hltпratrist'''has madе а rnirjorсontгibution to Rusе'''a wеll-krrown сгudе litеrаlism of сrеation sсiеnсе thеmoral rot. МOrе rесеntly' thе rz.rtlrеr hasmorphеd into thе morе sophistiсatеdanti-Dаrwinism ot so-сallеd IntеlligеntDеsignThеory' whiсh sееsaspесtsof oгganiс lifе as so сomplех as to геquirеspесial сrеativе intеrvеntions Ьy thе Dеsignеr. But still thе dеЬatе today is morе than just a сonfliсt of sсiеnсеvеГsl'lsrеligion and onе Ьеtwееn сompеtingidеolсlgiеs.Tlrе foundеr of thе lntеlligеnt Dеsign movеlnеnt' formеr BеrkеlеylzrwprotЪssсlrPhiilip Jсlhrrsorr,is ехpliсit ir-rsееing еvolutiоn irr thе ..Thе oldtеrms: Сhristian philosophy that Was ovегthrown in thе 1960s was an еasy targеt Ьесausе it had Ьесomе idеntifiеd with Amеriсan сulturе аnd with worldly idеas likе human pеrfесtiЬilityand thе inеvitaЬility of progrеss, whiсharе aсtually profoundly un-Сhristian'' (Johnson 1997,106), Unsurprisingly,this humanistiс mеtaphysiсsis linkеd to moral failings-pornography' gaymarriаgе,aЬoгtiol-l'аnd likе transgгеssionssuсh as soсialisrl.

Сonсlusion Thе history of еvolutionary thеory falls into thrее stagеs.From aЬout 1700 until 1859, it was littlе morе than a psеudosсiеnсеriding on thе Ьaсk of thе idеologyof progrеss,thе notion that humirns сan makе сЬangе for thе Ьеttеr. Itrvasopposеdto tгаditional rеligion not so r-nuсhЬесausеit wеnt against thе it lеft no plaсе for Prсrvidеnсе,thе Ьеliеf litеraltruth of rhе BiЬlе Ьut Ьесаr-rsе thatсhangесoп-lеsonly through Goсl's undеsеrvеdgraсе. Сharlеs Darwin's Оп thе origiп
4S

46

Tbе Historу of Еuolиtioпаrl, Thought pгotЪssional sсiеnсе oi еvolutior.rary сlrangе. This oссurrеd, arrd it is this thеOry that flourishеs today. Yеt еvсllr-rtiorrisrsshould nеvеr fсlrgеt thе past and its influепсе On thе prеsеnt. Alorrg witlr thе sсiеnсе thеrе is still an ongсling dеbatе about idеolog1. аnd thе ехtеnt to lvhiсh еvсrltrtion in somе wаY рrovidеs a sесulаr altеrnatir,е to oldеr' Ovеrtly rеligiorrs ways Of viеwing thе world and humankind's status within it. вlBLloGRAPHY Aristotlе. 1984. Dе pаrtibиs апimаIium.In J. Bаrnеs, еd'' Тbе Сomplеtе Works tf Aristotlе,1087_-l1 10. Prinсеton, NJ: Prinсеton University Prеss. Bаnnistеr, R. 1979. Soсiа! Dапuiпism: Sсiспсе dпd М1,уfiiп Апglo-Аmеriсшt Sсlсiаl Тhtlught' Plrilаdеlphia: Теrnрlе Univеrsitv Prеss. Brеwstеr,D. 1844. Vеsтigеs.Nortb ]]ritish RеL,iеlu3: 470_51'5. .W. Saptorno,and Brown, P., T. Sutikna, М' J. Мorwood' R. P. Soеjono' Jatrnikсl'Е. R. A. Duе. 2004. A nеw slnall.Ьodiеd horninin from thе Late Plеisttlсеrrсof Еlorеs, Indtlnеsia. Nсltцrе 43 1: 10.55-106 1. Burсlrfiеld,J. D. 197'5.Lord Kеluiп апd tЬе Аgе сlf thс Лarrl:. Nеrv Yoгk: Sсtеnсе History Publiсatiоns. Сain, A. I. 1954, Aпimаl Spесiеsапd.Гhеir I'uolиtioп. London: HutсhiIrson. Сarroll, S. B. 2005. Епdlеss Fсlrпts Мtlst Bеаutiful: Тhе Ncц, Sсiеttсеllf Еuс, Dсt,,tl апd thе Маkiпg of thе Aпimаl Кiпg&mt. Nец, Yсlrk: Nсlrton. СhamЬеrs, R. 1844' Vеstigеs of tbе Nаturtll Histrlrу сlf Сrеаtigу'of Tu,сl Sс;сe-с. Indianаpolis:Haсkеtt. Сooреr, J. М., ed. 1997 ' Plаto: Сomplеtе V(/or&s. Сuviеr, G. l817. Lе rёgпе апimаl distribиё d'аprёs soп rlrgшtisаtiсlп,ptlur sеruir dе bаsе i l'histoirе п,ltиrеllе dеs апitпсtttхеt d'iпtrotlисtioп i l'апаtrlпliе сrлпpаrёе. 4 vols. Paris: Dёtеrr.illе. Daеsсhlеr, Е. B.' N. H. Shubin, and F. A. Jеnkins Jr' 2006. A Dеvoniаn tеtraроd.likе fish and thе еvolution of thе tеtrapod Ьildy plan. Nсrиre 44О:757_76З. Darwin, С. l859. Оп thе Оrigiп о|.Spесiсs.Londсlrr:.|olrnN,tr-rrrаy. 1871. Thе Dеsсе|1trlf Мап,2 vols. London: .JohnМuгra,v. 19 59 . Тhе Оrigiп of Spесiеs bу Сhаrlеs Dаrшiп: А Vаriltuпl Техt. М. Pесkhаm, еd. Philadеlphia:Urrivеrsitуof PеnnsylvilniaPrеss. сlr, Thе Lаtus сl|.ОrgаltiсLifе,3rd еd. 4 vсlls.Lоndon; Darwin, Е. 1801. Z,сlсlllсlltliа; J. Johnsоn. 180З. Тbе TеnryIе of Nаtt,trе.Londсln: J. Johnson. Dawkins, R. 2006. Thе God DеIиsirlп' Boston: Houghton Мiff]in. Dеnnеtt, D. с. 1995. Dаrшiп's Dапgсrrllts1rlса.Nеш. Ytlrk: Siпrсlnаrrd Sсhustеr. Dеsпrond, ^. |994. Нuхleу,,thе Dеuil's Disсiрlе. I-ondon:Miсhaеl Jоsеph. 1997, Нuхlеу, Еuоlиtiспt'sHigh l,riеst,I,сlndсln:Мiсhаеl Josеph. DoЬzhаnsky, т ' 19з7. Geпеtiсs аlld thе Оrigiп of Spесles.Nеrv Yоrk: СolumЬia Univеrsity Prеss. Еldrеdgе' N., arrd S. J. GoLr[d.l972. PunсtuаtеdеqiriliЬriа:An irltеrllаtir.еttl ph1,lеtiс gradualism. ln T. ]. М. Sсhopf, еd.,Мodеls iп Pаlеobiсlklgу,tt2-1l.5. Sаn Frаnсisсo: Frееman, (,oopеr' Fishеr, R. A. 1930. ТЬе Gепеtiсаl Тhеor1' of Nаturаl Sеlесtitltt,Oхfсlгd: oхt.oгd Univеrsitу Prеss. Ford, Е. B. 1964' Есologiсаl Gепеtiсs, London: ]\4еthuеn. еvolutiorraryand GilЬеrt, S.F., J.M. Opitz, and R. A. Rаff. 1996. Rеsyrrtlrеsizing dеvеlopmеntаlЬiсllogy.Dеuеk)pmultаl Bklltlgу |7 З: З57_З72.

Gould, S. J. 1989. Woпder Nеw York: W. !7. Nor Gould, S. J., аnd R. C. Lеw Panglossianpаradigm of thе Roуаl Soсiеtу сl Grаnt, B' R., аnd P. R. Gra Populаtioп:Тhе Lаrgе Сhiсago Prеss. H a е с k е l ,Е ' 1 8 9 7 . . Г h сЕ u l l Poiпts of Humап oпtс аnd сompilny.

H а l d а n еJ, . B . S . 1 9 3 2 . . Г h H u l l , D . L . 1 9 8 8 .S с i е п с eа ,1942.Еuolut Huхlеy,]. S. Johnson,P. Е. |997. Dеfеа IntеrVarsityPrеss. Jonеs,G. |98О.Soсiаl Dаr Kеttlеwеll,Н. B. D. 1973. L a m а r с k J, ' B ' | 8 0 9 . P h i l o L y е l l ,C . l 8 3 0 - l 8 3 3 . P r i п с Сhаngеsof thе Еаrth's 3 vols.London:John l М a l t h u s ,T . R . I 1 8 2 6 11 9 1 L o n d o n :Е v е г y m а n . Маrshall' L. G., S. D. IWе еvolutitlnаnd thе grеа М а y г , Е . | 9 4 2 .S у s l с m а l i UnivегsityPress. М o r г i s ,H . М . | 9 8 9 . T h e I Сrеаtirln/Еuсllutio п С< N u m Ь е г sR , . L . 2 О 0 6 .Т h e Dеsigп.2ndеd. Сamb Owеn' R. |860. Pаlаесlпt G еologiсаl Rеlаtiсlпs. P a l е y ,W . [ 1 8 0 2 ]18 1 9 . N а Rivington. -W. Provinе, B. |971. Тhe с Univегsityof Chiсagс -Гhе Riсhаrds,R. I. 1992. Prеss. Rusе,М. 7996.Мoпаd to СаmЬгidgе,МA: Har 2ОО5.Тhе Еt',olut UnivеrsityPrеss. Sеdlеy,D. 2008. Сrеаtiсlп CalifоrniaPrеss. S е p k o s k iJ,. J . ' J r . 1 9 7 6 .S Pаlеlэbblogу2, no.4 S h е p p а r dP, . М . l 9 5 8 . N . Simpson,G. G. |944. Теr UnivеrsityPrеss. | 9 4 9 .T b е М с а n i Spеnсеr'Н. 185|, Soсiаl Spесifiеdап,l thе Fir.

Тhе Histrlrу of Еuolutioпаrу

angе.This oссllrrеd' and it is this thеnists shоulсirrеvегforgеt thе past аnd .h thе sсiеnсеthеrе is still irrr ongoing to whiсh еvolution in somе Way рro)Vеrtlyrеligious Ways of viеwing thе t.

J. Barnеs' ed.,Tbс Сomplеtе Worhs of ) г i l r с е t o nU n i v е r ч i t rP.r е s ч . 'ltcе апd Nl1'thiп Апglo-Апte riсttп Sсlсiаl 'sityPrеss. Rеuiеl.e'3: 470_.j 1.5. .W. P' Soеjono,Jatmiko, Е. Sаptomo, and hoп-rininfrоm thr'-Lаtе Plеistoсеnt-of

r061.

с Аgе of thе ЕлrfД. Nеw York: Sсiеnсе , Еuolutioп. London: Hutсhinson. еаutiful: Thе Nеu, Sсiепсе of l:url Dеuo 'zll.Nеrv York: Noгtоn. il Histсlrуоi Сrеаtiсlп.London: Сhurсhill. vу of Сrеаtioп. .5thеd. London: Сhurсhill. S' D. АlЬon. 1982, Rеd Dееr: Bеhаuior Jnivеrsityсlf Сhiсago Prеss. lVorДs.lndiаnapolis:Haсkеtt. i d'аprёs soп tlrgапisаtiсlп,ptlнr sеruir dе . еt d'iпtrodисtitlп Й l'аllаtomiе с()mpаrёe. еnkinsJr. 2006. А Dеvсlniantеtгapсrd-likе Ьodv plan. Nаturе 440:757_76З' s. London: John N,luгrav. . London;John Мurray. |аrlеsDаrlui|I: А Vаriоrum Tехt. \4. of Pеnns1.lvаnia Prеss. s of Оrgапiс Lifе. 3rd еd. 4 vсlls. London: 1orr:J. Jсlhnson. ;tоn: Houghton Мifflin. 1deс.Nеw York: Simоn arrd Sсhustеr. .sсlple.London: NIiсhaеlJosеph. riс,-s,' Lсlndon: Мiсlrаеl Josеph. rigiп сlf Spесiеs.Nсw Yоrk: СoiumЬia uаtеd еquilibria: An аltеrnativе to phylеtiс сldеlsiп Pаlеobioklgу, 82_1 15. San ,f Nаturаl Sеlесtit-lп,Oхford: oхf
Thought

Gould, S. I,1989.\ilrlпderful I-ifе: Thе Bиrgess ,Shаlеапd thе Nаtнrе of Нisttlrу' Nеw York: W. W. Nсlrrсlп. Gould,S. J., and R. С. Lеwontirr. |979. TЬе spandгеlsof San ]vIаrсoand thе Panglossianpi1гadigm:A сritiquе of thе аdaptationist progr:rmme. Proсееdiпgs of thе Roуаl Soсiеtу of Londoп' Sеriеs B 205: 581_598. Gгаnt' B. R., and P. R. Grant. 1989. ЕuolutiLlпаr1l f)уn47niсs оf а Nаtиrаl Populаtion:ТЬе Lаrgе Сасtus Fiпch of thе Gоltipаgоs. Сhiсirgo: L}nivеrsity of Сhiсago Prеss. Haесkеl,Е. 1897. The Еuсllutil.lпof Мап: A Po1lulаr Ехpсlsitioll of thе Priпсipаl Poiпts of Humап oпtogепу апd Phуlсlgепy. 2 vols. Nеw York: D. Applеton and Company. Haldanе'J. B. S. 1932. Thе Сацses сlf Еuolutioп. Nеw York: Lоngtnans, Grееn. Hull, D. L. 1988. Sсiепсеаs а Proсеss.Сhiсаgo: Llnivеrsityof Сhiсagо Prеss. Huхlеy,J. S. 1942, Еuolиtioп: Thс Мodеrп Sуtthеsis. London: Allеn and Un'*,in. Johnsоn,P. F,. 1997. Dеfеаtiпg DLlrшiпism bу Оpепiпg Мiпds. Downеrs Grovе, IL: IntеrVarsityPгеss. Jonеs,G. 1980' Soсiаl Dаrшiпism апd Епglish Thсlиght, Brightor-r,U.K.: Наrvеstег. Kеttiеwеll,Н. B. D. 197З. Thе ЕuпsЕssеntiаl tсl Hиmап Hаp|liпеss Specifiеdапd thе First of TЬеllt Dеuеlopеd. Lоndon: J. Chapman.

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Тhe Historу of Еuсэlutioпаrу Тhсlltght 1857. Progrеss:Its law and сausе. WеstmiпsterReuieш 67:244-267, Stеbbins,G. L. 1950. Уаriаtioп апd Еuolutiсlп iп Plапts' Nеw York: СolumЬiа Univегsity Prеss. Tеilhаrd dе Сhardin. P. 1955. Lе phёпomёпе hнпшiп. Pаris: Ес]itionsdu Sеrril. Vorzimmеr, P. J. 1970. Сhаrlеs Dаrшiп: Thе Yеаrs сlf Сoпtrouеrsу. Philadеtphil: Tеmplе Univеrsity Prеss. .Wallaсе, A' R. 1858. On thе tеndеnсv of variеtiеsto dеpart infinitеly from thе оriginal tvpe. .|tlurпаl of thе Proссеtliпgs сlf thе Liппаеап Soсiеtl,,Zсlologу 3: 5з-62. 1870. Сoпtrillцtitlпs to thе Thеorу of Nаtltrаl Sеlесtiсlп:A Sеriеs of Еssауs. London: МасmiIlan. .Wilson, Е. o. |975. Soсiсlbiсllсlgу: Тbе Neш Sупthеsis,СamЬridgе' МA: Bеlknap Prеss сlf Hаrvаrd Univеrsitv Prеss' |978. Оп Htttпап Nаturе. Сambridgе, МA: Нarvard Univеrsity Prеss. Wright, S. 1931. Еvolrrtion in Mеndеlian populаtions. Gепеtiсs 16:97_1,59. 1932'Thе rolеs of mutatiOn' inЬrееding,сгossЬrееdingand sеlесtionrn еvo]ution. Proсcеdiпgs rlf thе Siхth Iпtеrпаtitlпаl Ссlпgrеss oi Gепеtiсs 1: з56_З66.

Thе orig

JеffreуL. Bа

Gеnеrаtions of sсiеnt tiоn of thе origin of ally is as сеrtain as surround us.

Нow. whеrе. and whеn r wаs геluсtant to addrеss r |, 1871.,to his friеnd Jr paragraph that ..it is oftе of a living Ьеing arе now (and oh what а Ьig if) w sorts of ammonia аnd ph a Protеin сompoulrd Wа сomplех сhangеs' at thе ] аЬsorЬеd, whiсh would l formеd'' (Darwin 1887, Cambridgе. It is геfеrеnс rеproduсed in Сalvin 19t Darwin's lеttеr nоt onl; of lifе Ьut also providеs сt naturе of thе Ьasiс Ьiolog sсiеntifiс сirсlеs. Althоugl сallеd thеm nuсlеin) in 18 in gеnеtiс proсеssеs woul trast' thе rolеs plаyеd bу firmly гесognizеd. Еquall' jor advanсеs had Ьееn m. wЬiсh for a long timе hаr ganiс сompounds. Thе ех Alеksandr Butlеrov, who laЬorаtory synthеsis of r starring matеrials, wеrе r sеpаratingorganisms frol

WеstminstеrRсuiеtl,,67: 244_267 . tiсlп iп Plаnts, Nеw York: СolumЬia эnc humаin. Pаris: Еditions du Sеtril. 'hе Yeаrs of СlлtroL,,еrsу.Philаdеlphia: а r i е т i е rso d е p a r ti n f i n i t е I yГ r o m г h е tgsсlf the Liппаеап Soсiеtу, Z
Thеorigin of Lifе leffreуL. Bаdа аnd Аntonio Lаzсапo

ш Sупthesis,СamЬridgе, MA: Bеlknap idgе,МA: Hаrvаrd Ur-rivеrsity Prеss. loрulations.Gеnеtiсs |6: 97-| 59 . эеding,сrossЬrееdingаnd sеlесtionin tеrnаtioпаl Сгlпgrеss of Gепеtiсs I:

Gеnеrationsof sсiеntistsmаy ).еthavе to сomе and go Ьеforе thе quеsгion of thе origin of lifе is finаl11'sсllvеd.That it lvill Ье solvеd еvеrttually is аs сегtаin аs аnything сan еvеr Ье amid thе unсеrtaintiеs that suгroundus. Еari AlЬеrt Nеlson, TЬеrе Is Lifе oп Маrs (1956\

How, whеrе,and whеn did lifе appеar on еarth? Although Сharlеs Darwin wasrеluсtantto addrеssthеsеissuеsin his Ьooks, in a lеttеr sеnt on FеЬruary 7, 1877, to his friеnd Josеph Dalton Нookеr, hе wrotе in а now_famous paragraphthat ..it is oftеn said that аll thе сonditions for thе first pгoduсtion of a livirrgbеing arе now prеsеnt,whiсh сould еvеr havе Ьееn prеsеnt.But if (аndoh what a big if) rvе сould сonсеivе in somе warm littlе pond with аll sortsof ammonia and phosphoriс salts,-light, hеat, еlесtriсityprеsеnt' that a protеinсompound was сhеmiсirlly fornrеd, rеady to undеrgo still morе сomplеxсhangеs,at thе pгеsеntsuсh mattеr would Ье instantly dеvourеd' оr absorЬеd,whiсh wоuld not havе Ьееn thе сasе Ьеforе living сrеaturеs wеrе formеd''(Darwirr 1887, 'i, 18). (Thе lеttеr is in thе Darwin Сollесtion in Сambridgе.It is rеfеrеnсеdas Lеttеr 747 | in Burkhаrt and Smith l994 and is rеproduсеd in Сalvin 7969,4_5.) DагwirrЪlеttеr not onlv summаrizеs in a nutshеll his idеas on thе еmеrgеnсе of lifе but also providеs сonsidеraЬlе insights on thе viеws aЬout thе molесular naturеof thе basiс biologiсal proсеssеsthat wеrе prеvalеnt at thе timе ln mаny sсiеntifiссirсlеs.Although Friеdriсh Мiеsсhеr had disсovеrеd nuсlеiс aсids (hе сallеdthеm nuсlеin) tn 1869 (Dahm 2005)' thе dесiphегing of thеir сеntral rolе in gеnеtiсproсеssеswould rеmаin unknown for morе than 80 yеars. In сon. trast'thе rolеs playеd Ьy protеirrs in mаnifold Ьiologiсal pгoсеSsеshad Ьееn firmlyrесognizеd.Еqually signifiсant, by tlrе timе Darwin wrotе his lешеr, major advanсеshad beеn madе in thе undеrstandingof thе matеrial Ьasis of lifе, whiсh tЪr a long timе had bееn сonsidеrеd fundaпrеntally diffеrеnt from inoг.!76hlеr, ganiссompounds.Thе ехpеrimеnts of Friеdriсh Adolph Streсkеr, and AlеksаndrButlеrov, who hаd dеmorrstrаtеdirrdеpеrrdеntlyгhе fеаsiЬility of the laboratorysynthеsis of urеa, alаninе, and sugars, rеspесtivеly' from simplе startingmatеrials,Wеrе rесognizеd as a dеmonstration that thе сhеmiсal gap sеpаIating organisms fronr thе nonliving was not insurпrtlr.rntaЬiе. 19

F 50

The Оrigiп of Lifе But how had this gap first Ьееn Ьridgеd? Thе idеa that lifе Was an emеrgеnt fеaturе of naturе has Ьееn widesprеad sinсе thе ninеtееnthсеntury. Thе major Ьrеakthroughs that transformеd thе origin of lifе from purе spесula. tion into workaЬlе and tеstablе rеsеarсh modеls wеrе proposals that wеrе suggеstеdindеpеndеntly in thе 1920s Ьy Alеksandr I. oparin and J. B. S. Haldanе, as wеll aS othеrs (sееBada and Lazсano 200З). Thеy hypothеsizеd that thе first lifе forms wеrе thе outсomе of a slow, multistеp proсеss that Ьеgan with thе aЬiotiс synthеsisof organiс сompounds and thе formation of ..primordial soup.'' Hеrе thеir proposals divеrgеd. Whilе Haldanе arguеd a that virusеs rеprеsеntеda primordial stagе that had appеагеd prior to сеlis' opаrin arguеd that сolloidal, gеl.likе systеms had formеd from thе soup, lеading to anaеroЬiс hеtеrotrophs that сould takе up surrounding organiс сompounds and usе thеm dirесtly for growth and rеproduсtion. Although thе dеtails of thеsе idеas havе Ьееn supеrsеdеd' thе oparin-Haldanе hypothеsis of сhеmiсal еvolution providеd a сonсеptual framеwork for thе еxpеrimеntal dеvеlopmеnt of thе study of thе оrigin of lifе. LaЬoratory еxpеrimеnts havе shown how еasy it is to produсе a variеty of organiс сompounds, inсluding Ьioсhеmiсally important monomеrs' undеr plausiblе сosmiс and gеoсhеmiсal сonditions. Thе roЬust naturе of thеsе rеaсtions has Ьееn dеmonstratеd Ьy thе finding that organiс сompounds arе uЬiquitous in thе univеrsе, as shown by thеir prеsеnсеin сarbon.riсh mеtеoritеs'сomеtary spесtra' and intеrstеllar сloцds whеrе star and planеtary formation is taking plaсе.

A Timеsсalе for thе Еmеrgеnсеof Lifе Although traditionally it had Ьееn assumеd that thе origin and еarly еvolu. tion of lifе involvеd sеvеral Ьillion yеars (Lazсano and Millеr 1994), suсh viеws arе no longеr tеnaЬlе. It is truе that it is not pоssiЬlе to assign a prесisе сhronology to thе appеаranсеof lifе, Ьut in thе past fеw yеars еstimatеS of thе timе within whiсh this must havе oссurrеd havе Ьееn сonsidеraЬly rеduсеd. Dеtеrmination of thе Ьiologiсal origin of what havе Ьееn сonsidеrеd thе еarliеst traсеs of lifе is now a rathеr сontеntious issuе (van Zuilеn еt al. 2o0z). This is not surprising. Thе gеologiсal rесord of thе еarly Arсhеan is sparsе' and thеrе arе vеry fеw roсks that arе morе than 3.5 Ьillion yеars old. Thе roсks with agеs grеatеr than 3.5 Ьillion yеars that arе prеsеrvеd havе bееn еxtеnsivеly altеrеd Ьy mеtamorphiс proсеssеs(van Zg||en et a|.2002|, and thus any dirесt еvidеnсе of anсiеnt lifе has apparеntly Ьееn largеly oЬlitеratеd. Although the Ьiologiсal naturе of thе miсrostruсrurеsprеsеnt in thе 3.5 Ьillion.yеar-old Apех сhеrts of thе Australian !Иarrawoona formation (Sсhopf 1993) has Ьееn disputеd (Brаsiеr еt a|. 2002; Garсia-Ruiz еt al. 2003), thеrе is еvidеnсе that lifе еmеrgеd on еarth vеry еarly in its histоry. Thе proposеd timing of thе onsеt of miсrobial mеthanogеnеsis,Ьasеd on thе low 1зС valuеs in mеthanе inсlusions, has Ьееn found in hydrothеrmally

prесipitаtеdquartz in thе (Uеno еt a|' 2006), аlthou МсCollom 2006). Howеv diсatе Ьiologiсal sulfatе-r 3.4 billion-yеar-old Sout} rinе еnvironmеnt inhaЬit аnd Lowе 2004\' Thеsе r old stromatolitеs from W idеa thаt thе еarly Arсhеa origin of lifе must havе ta pеrmit thе survival of thе Thе еarly Arсhеan foss quirеd for thе origin and r сritiсal faсtor may havе Ь. siЬlе аs soon as thе planе watеr. Unfortunatеly, tht с o n d i t i o n so n t h е е а г l у е а lесulаr or physiсаl rеmni еvolutionаry proсеssеs th ganisms found in the еarl ing not only on thе сoп pегiod of thе origin of lifr gеnеral and loсal еnvlroг impoгtant for thе еmеrgе

Thе Primitivе Еarth

ConsidеraЬlе progrеss ha сonditions of thе еarly е сhеmistry may havе oссr thеrе arе still еnormous сompounds assoсiatеdwi ing еntitiеs and how thеs t u а l е v i d е n с еo f t h е i r е х i havе bеgun on еarth' wе ] history and undеr what thе origin of lifе took pl. liquid watеr and oгganiс availablе еvidеnсе suggе lасkеd protеins and dеpе сlеotidеs, Ьut watеr was vidеs thе mеdium for сh сomponеnts, as far as wе It is unlikеly that Watе ing thе Hadеan pеriod tl

Thе Оrigiп of Life dgеd?Tlrе idеa that litе was an еmеrlrеad sinсе tlrе ninеtееnth сеntury. Thе d thе origin of lifе from prrrе spесulaLrсh modеls Wеrе proposals that wеrе s Ь y A l е k s a n d rI . O p а r i n а n d J . B . S . nd Lаzсano 2003). Thеy lrypothеsizеd omе of a slow, multistеp proсеss that 4aniссomptlundsand thе formation of osals divеrgеd'Whilе Haldanе arguеd stаgеthat had appеared prior to сеlls, 3 systеms lrаd formеd frorn thе soup, at сould takе up surrounding organiс r growth and rеproduсtion. Although supеrsеdеd,tlrе Oparin-Наldanе hy_ idеd a сonсеptual framеwoгk for thе 'rdy of thе origin of lifе. LaЬoratory s to produсе a variеty of organiс сom)rtant monotnеrs,undеr plausiЬlе сos. э robust natuГе of thеsе rеaсtions has г organiс сompounds arе uЬiquitous in с е i n с а r Ь o n - r i с hm е t е o r i r с sс, o m е t a r y star and planеtary formation is taking

е of Lifе sumеd that thе origin аnd еarly еvoluе a г s ( L a z с a n oа n d М i l l е r 1 9 9 4 ) , s u с h . t h a t i t i s n o r p o s s i Ь l еr o a s s i g n a p r е l i f е ' Ь u t i n r h е p a s t f е w у е . r r sе s t i m a t е s vе oссurrеd havе Ьееn сonsidеraЬly rеal origin of wlrat havе Ьееlrсonsidеrеd 1егсontеntiousissuе (varrZuilеn еt al. clogiсal rесord of thе еarly Arсhеan is |ratarе morе than 3.5 Ьillion yеars оld. i Ьillion yеars that arе prеsеrvеd havе lhiс prосеssеs(van Zuilеn et a|.2002|, ;iеnt llfе has apparеrrtly Ьееn |arge|у thе miсrostruсtrrrеsprеsеnt in thе 3.5 э Australian NИarrawoonа formation ,гasiеrеt a\' 20021 Garсia-Ruiz еt al. rgеd orr еilrth vеry еarly in its history. niсroЬiаlmеthanogеnеsis,Ьasеd on thе ts, has Ьееn found in hydrothеrmally

prесipitatеd qtlartz in thе З..SЬillion-yеar-old Drеssеr Formation in Australia (Uеnoеt al. 2006), although tlris finding has i.rlstlЬееn сhallеngеd (Lollar and МсСollom 2006). Howеvеr, sulfur isotopе invеstigationsof thе samе sitе indiсatеЬiologiсalsulfatе-rеduсingасtivity (Shеn еt al.2001), and analysеsof 3'4 Ьillion-yеar_old South Afriсan сhеrts suggеstthat thеy forrnеd ln a marinе еnvironmеntinЬaЬitеd Ьv anaеroЬiс photosynthеtiс pгokaгyotеs (Tiсе and Lowе 2004). Thеsе rеsults' сomЬinеd with rеports on З.43 Ьillion-yеаrold stromatolitеsfrom .JИеstеrnAustralia (Allwood et a|.2007), support thе ideathat thе еarl,vArсhеan еarth Was tееming rvith prokaryotеs' and that tlrе originof lifе mr"rst hаrvеtakеn plaсе as soon as tlrе сonditions wеrе suitaЬlе to pеrmitthе survivаl of thеsе tvpеs of organisnrs. Тhе еarly Arсhеan fossil rесord spеaks for thе rеlativеly short timеsсalе rеquirеdfor thе origin and еarly еvolution of lifе on еarth and suggеststhat thе сritiсalfaсtormaу havе ЬееrrtЬе Prеsеnсеof liquid watеr' whiсh Ьесamеpossiblеаs soon as tlrе planеt'ssurfасе finаlly сoolеd Ьеlorv thе Ьoiling point of wаtеr.Unfortr-rnatеiy, thеrе is no gеologiсal еvidеnсе of thе еnvironmеntal сonditionson thе еarly еarth at thе timе of tlrе origin of lifе, nor arе any molесuiar or physiсal rеmnants pГеsеrvеd that providе infornration aЬout thе еvolutionaryproсеssеsthat prесеdеd thе appеaranсе of thе fiгst сеllular organismsfound in thе еarly fossil reссlrd.Dirесt inforпratiorris gеnеrally lасk_ ing not only on thе сomposition of thе tеrrеstrial atmosphеrе during thе pеriodof thе origin оf lifе Ьut also on thе tеrnperaturе' oсеan pH, and othеr gеnеraland loсаl еnvironmеntal сonditions that may or may not havе Ьееn impoгtantfor thе еmеrgеnсеof living systеms'

Thе Primitivе Еarth Еnvironmеnt progrеsshаs Ьeеn lrradеin our undеrstandingof еnvironmеntаl СonsidеraЬlе сonditionsof thе еarly еarth аnd how tlrе transition frorn аЬiotiс to Ьiotiс сhеmistrymay havе oссurrеd (for ехаmplе. sее Bada 2004). Nеvеrthеlеss, thеrеarе still еnormous gaps in our dеsсription of how thе simplе Orgаnrс сompoundsassoсiatеdwith lifе аs wе know it геaсtеdto gеnегatеthе first liviпgеntitiеsand how tlrеsеin trrrn еvolvеd into orgаnisms thаt lеft Ьеhind aсtuаlеvidеnсеof thеir ехistеnсеin thе roсk rесоrd. Тo еvaluatе how lifе may havеЬеgunon еarth' Wе must aссеsswhat thе planеt was likе during its еaгly historyand undеr what сonditions thе proсеssеsthought to bе involvеd in thе origin of lifе took plaсе. Lifе as wе know it dеpеnds on thе prеsеnсе of [iquidwatеr and oгganiс polr,mеrs suсh as rruсlеiс aсids аnd proteins. Thе аvаilaЬlееvidеnсе suggеsts tl-ratduring arr еarly stagе, Ьiologiсal systems laсkedprotеinsand dеpеndеdlargеly on сatalytiс and rеpliсativе polyriЬonuсleotidеs'Ьut watеr was likel1.еssеntial fronr thе vеry Ьеginning, as it providеsthе mеdium for сhеmiсal rеaсtions tсl tirkе plaсе' Withоut thеsе Ьasiс сomponеntsJ i1sfar as wе know, lifе is irrrpossiblе. It is unlikеly that watеr mаdе its first appеaranсеon еartlr as a liquid. During thе Hadеan pеriod thе volatilе сomponеnts that wеrе trappеd insidе thе

52

Тhe origiп of Lifе aссrеting planеt wеrе rеlеasеd (dеgassеd)from thе intеrior of thе juvеnilе еarth to form a sесondary atmсlsphеrе.Any primary atmosphеrе (if onе ехistеd at all) must havе Ьееn lost' as еvidеnсеdЬy thе dеplеtion of rarе gasеsin thе еarth's atmosphегесomparеd with сosrniс aЬundanсеs (Kasting 1'99ЗьI. As a сonsеquеnсе of thе nеarly simultanеous formation of thе еarth's сorе with aссrеtion, thе mеtalliс iron was rеmovеd from thе uppеr mantlе, whiсh would havе allowеd thе volсaniс gasеsto rеmain rеlativеly rеduсеd аnd produсе a vеry еarly atmosphеrе thаt сontainеd spесiеssuсh as СHo, NH-., and H,. Sinсе thе tеmpеraturе at thе surfaсе was high еnough to prеvеnt any Watеr from сondеnsing, thе atmosphеrеwould havе сonsistеd mainly of supеrhеatеd stеam along with thеsе othеr gasеs (Kasting 1993a|' Еvеn though thе sесondary atmosphеrе may havе Ьееn lost sеvеrаl timеs during largе-impaсt еvеnts, еspесially thе onе that formеd thе moon, it would havе Ьееn rеgеnеratеd Ьy furthеr outgassing from thе intеrior, as wеll as Ьеing rеsuppliеd from latеr impaсtors. It is gеnеrally aссеptеd that thе impасtors during thе lаtеr stagеs of thе aссrеtion proсеss originatеd from outsidе thе solar systеmand wоuld hаvе Ьееn similar in сomposition to сomеts. As suggеstеdin 1961 Ьy thе lаtе Spanish сhеmist Joan (John) 016' сomеtаry volatilе сompounds, whiсh appеar to Ье thе most pristinе matеrials that survivе from thе formation of thе solar systеm' may havе suppliеd a suЬstantial fraсtion of thе volatilеs on thе tеrrеstrial planеts, pеrhaps inсluding organiс сompounds that may havе playеd a rolе in thе origin of lifе on еarth (016 7961).It has Ьееn suggеstеdthat thе watеr on thе еarth was providеd еntirеly from this sourсе. Howеvеr, rесеnt mеasrrrеmеntsof thе dеutеrium сontеnt of watеr in сomеts Hallеy, Hyakutakе, and Halе-Bopp indiсatе that сomеts dеlivеrеd only a fraсtion of it, whilе thе largest fraсtion Was trappеd during thе еarliеr aссrеtionary phasе and rеlеasеdvia dеgassing(RoЬеrt 200] ). It is rеasonaЬlе to assumе that thе atmosphеrе that dеvеlopеd on thе еarth ovеr thе pеriod 4.4 t'oЗ.8 Ьillion yеars ago (pеrhaps sеvеral timеs if it was еrodеd Ьy largе-impaсt еvеnts) was Ьаsiсally a miх of volatilеs dеlivеrеd Ьy volatilе-riсh impaсtors suсh as сomеts аnd оutgassing from thе intеrior of an alrеady-diffеrеntiatеdplanеt. This atmosphеrе was probaЬly dominatеd Ьy watеr stеam until thе surfaсе tеmpеraturеsdroppеd to -100"С (dеpеnding on thе prеssurе),at whiсh point watеr сondеnsеd to form еarly o с е a n s ( W i l d е е t a l . 2 0 0 1 ) . T h е r е d u с е d s p е с i е s ,w h i с h w е r е m a i n l y s u p pliеd Ьy volсaniс outgassing,arе vеry sеnsitivеto ultraviolеt (UV) radiation that pеnеtratеd thе atmosphеrе Ьесausе of thе laсk of a protесtivе Ozonе layеr. Thеsе molесulеs wеrе probaЬly dеstroyеd Ьy photodissoсiation, al. though thеrе might havе Ьееn a stеady-statееquiliЬrium Ьеtwееn thеsе two proсеssеs that allowеd a signifiсant amount of thеsе rеduсеd spесiеs (еspесially H,) to Ье prеsеnt in thе atmоsphеrе (for ехamplе, sее Tian еt al. 2005). Еvеntually, as H, еsсapеd from thе еarth into spасе, rеduсеd spесiеs in thе atmosphеrе would havе Ьееn dеplеtеd. Thus, in gеnеral thе ovеrall сonsеnsus at prеsеnt is that the еarly atmosphеrе was dominatеd Ьy oxidizеd molесulеs suсh as Сo,, СO' and N,. A similar atmosphеrе is prеsеnt

on Vеnus today, althou еarly еarth. Thе сlimatе on thе е tors: thе luminosity of phеrе. Standard thеorе aЬout З07" lеssluminс thе еarly еarth Wеrе th would havе Ьееn frtlz ( 1 9 9 З a , 1 9 9 3 Ь ) a' С o , thе Hadеan and Еarly housе еffесt that woulс frееzing. Thе Ьasiс arg tory, thеrе wеrе proЬa tеnsivе siliсatе Wеathе loss proсеss for СO' rеl havе Ьееn primarily сo assumptionoГ а solаг statе atmosphеrе сonta ordеr to maintаin а г point of Watеr. In summary, thе сurt gеst that it сonsistеd < Н,o, with lеssеr amout and NН. arе сonsidеrе izеd rеgions nеaг volсaп During suсh еarly trr and largе сontinеnts ha( еrations of thе еarly сar сling of сrustal sеdimеn surfaсе would havе rеm Ьonatе (Slееp and Zahт соnсеntrations in thе еа foгmatiоn of a gloЬal i dееd thе сasе, thе thiсkn thе tlrdеr of 300 m, whi an impaсtoг of *100 kr mеlting Ьolidеs has Ьее twееn aЬout З.6 and 4 сyсlеs assoсiatеd with tl portеd Ьy thе impасto would havе Ьееn washе Ьееn tеrmеd ..ImpaсtSu H,' and Сo dеrivеd fro unfrozеn oсеan Ьеlow t from UV radiation. Aft, ехpеllеd into thе atmos

Thе Оrigiп of Lifе sеd) from thе intеrioг of thе juvеnilе l. Any primary iltlтlosphеrе(if onе еxlеnсеdЬy thе dеplеtionof rarе gasеs in сosmiс abundanсеs(Kasting \99Зь). tanеous formation of thе еarth's сorе эmovеdfrom thе uppеr mantlе' whiсh to rеmаin rеlаtivеlyгеduсеd and prсltainеd spесiеssuсh as СHo, NH.., arrd е was high еnough tO prеvеnt any Waмould havе сonsistеd mainly of supеrlsеs (Kasting \99Зa). Еvеn though thе lost sеvеraltimеs dr-rringlargе-impaсt thе moon, it wсlr"rldlravе Ьееn rеgеnеr.еriоr'as wеll as Ьеing rеsuppliеd from rсtors during thе lаtеr stagеs of thе aс: thе solar systеm and rvould havе Ьеen sug'gеstеd in 1961 Ьy thе lаtе Spаnish 'lаtilесompounds, whiсh appеar to Ье е from thе fоrmation of thе solar sys_ fraсtion of thе volаtilеs on thе tеrrеsiс сompounds that may havе playеd а l 1961|' It has Ьееn suggеstеdthat thе .еly from this sor.rrсе. Howеvеr, rесеnt nt of watеr in соmеts Hallеy, Hyakulmеts dеlivеrеd only a fraсtion of it, l during thе еarliеr aссrеtionary phasе )1). е atnrosphеrеthаt dеvеlopеd On thе n yеars ago (pеrhapssеvеral timеs if it vas Ьasiсally a miх of volatilеs dеliv_ ls сomеts and outgassing from thе inаnеt. This atmosphеrе was proЬаЬly rfасеtеmpеraturеsdгoppеd tо -100"С L point watеr сondеnsеd to form еаrly rсеd spесiеs'whiсlr wеrе mainly sr.rpsеnsitivеto ultravitllеt (UV) radiation usс of thе laсk of а protесtivеozonе y dеstroyеdЬy photodissoсiation, aly-stаtееquiliЬrium Ьеtrvееnthеsе two mOunt of thеsе rеduсеd spесiеs (еspеlsphеrе (for ехamplе, sее Tian еt аl. n thе еarth into spасе, rеduсеd spесiеs dеplеtеd.Thus, in gеnеral thе ovегall r atmosphеrеwas dominatеd Ьy oхid N2. A similаr аrпrosphеrеis prеsеnt

o n V е n u st o d а у , a l t h o r r g hi t i s r т u с h m o r е d е n s еt h a n t h е a t m o s p h е г еt t f t h е еаrlvеartlr. Тhе сlimatе ()l1thе еarly еartlr аt this stаgе dе;lеndеd mainly otr two fасtors:thе luminosity of thе sun аnd thе radiativе propеrtiеs of tlrе atlтosphеrе.Standardtl.lеorеtiсalsolar-еvolution modеls prеdiсt that thе sun W:1s , i l l i l a n d 1 9 8 9 ) . I f t h е e t m o s p h е r еo f a Ь o u t3 0 % l е s s l u m i n o u s t h а n t o с . l i r (r G thееагly еarth WеГеtЬе samе as it is ll()w' thе еntiге stlrfaсе of thе 1rlаnеt would havе Ьееn fгozеn. Hoш,еvег, аs disсr.rssеdеxtеnsivеly Ьr. Kаstirrg \ | 9 9 3 a ,1 9 9 3 Ь ) ,а С O , - r i с h a t п r o s p h е r еm a y h а v е Ь е е n p r е s е n tr l r r o u g h t l u t thе Нadеan and Еarly Arсhеan pеriods, rеsulting in a signifiсant grееnhousееffесtthаt would havе pгеvеntеd thе oсеаns on thе еarly еarth from f г е е z i n gT. h е Ь а s i с a r g u m е n t i s t l r a t d u r i n g t h i s p е г i o d o f е a r l y е a г t h h i s tory' thеrе ц,еrе prсlbаЬly no rrrаjсlrсontinеnts, аrrd thtls tlrеrе rr,аsno ехtеnsivеsiliсatе wеathеring. Bесar.tsеthis proсеss is nowаdays tI-rе[ong-tеrnr lossproсеssfor СO, rеm
t.l

.\4 Thе Оrigiп of Lifе Ьеforе thеy wеrе dеstroyеd Ьy photoсhеmiсal rеaсtions. During thеsе еpisodеs highly rеduсing сonditions may havе prеvailеd.

organiс Сompounds on thе Primitivе Еarth Today organiс сompounds arе so pеrvasivе on thе еаrth's surfaсе that it is hard to imaginе thе еarth dеvoid of organiс matеrial. Howеvеr, during thе pеriod immеdiatеly aftеr thе еarth first fornrеd sсlmе 4.5 Ьillion yеars ago' thеrе would havе Ьееn no orgаniс сompounds prеsеnt on its surfaсе bесausе soon aftеr aссrеtion thе dесay of rаdioасtivе еlеmеntshеatеd thе intеrior of thе young еаrth to thе mеlting point of roсks (\Х/еthеrill1990). Volсaniс еruptions ехpеllеd moltеn roсk and hot sсorсhing gasеs out of thе juvеnilе еarth'sintеrior, сrеating a global infеrno. In addition, thе еarly еarth wаs also bеing pеppеrеdЬy mountain-sizеdplanеtеsimals,thе dеЬris lеft ovеr aftеr thе ассrеtion of thе planеts. Мassivе volсaniс сonvulsions, сouplеd with thе intеnsе ЬomЬardmеnt from spaсе' gеnеratеd surfaсе tеmpеraturеs so hot that thе еarth at this point сould vеry wеll havе had an ..Oсеаn''of moltеn roсk ( i . е . 'a m a g m a o с е a n ) . Although tеmpеraturеswould hаvе slowly dесrеasеdas thе infali of оЬjесts from spaсе and thе irrtеnsity of volсaniс еruptions dесlinеd, еlеvatеd tеmpеr. аturеs likеly pеrsistеdfor pеrhaps 100 milliсln yеars or longеr aftеr thе for. mation of thе еarth. During this pеriod tеmpеraturеswould proЬaЬly havе Ьееn too hot for organiс сompсlunds to survivе. !Иithout оrganiс сompounds, lifе as wе know it сould not havе ехistеd. Howеvеr, on thе Ьasis of data from аnсiеnt zirсons, Ьy approхimate|у 4 Ьillion years ago (or pеrhaps еvеn еarliеr) thе еarth's surfасе must havе сoolеd to thе point that liquid watеr сould ехist and gloЬal oсеans сould Ьеgin tсl form (!(zildееt al. 2001). It was during this pеriod that organiс сompounds would hаvе first startеd to ассumulatе on thе еarth's surfaсе,as long as thеrе wеrе aЬiotiс proсеssеsЬy whiсh thеy сould synthеsizеаnd aссumulatе.!Иhat Was thе naturе of thеsе proсеssеs?

Butlеrov, who show аlysts, suсh аs сalсil ars. Thе laЬoratory to inсludе morе сor tееnth сеntury a lar1 formеd (Bada and L Howеvеr, thеsе n as laЬoratory simul: to Hookеr, Ьut rath. of nitrogеn assimila cano 20О2a). Thе fi organiс сompounds Stanlеy L. ivlillеr, wa wееk on a mixturс protеin amino aсids organiс molесulеs (l Millеr aсhiеvеd h simulatе thе intеraс As an еnеrgy sourс sесond-largеstеnеrg

Synthеsisof organiс сompounds on thе Primitivе Еarth? Thе hypothеsisthat thе first organisms Wеrе anaеroЬiс hеtеrotrophsis Ьasеd on thе assumption that aЬiotiс organiс сompounds wеrе a nесеssary prесursor for thе appеaranсе of lifе. Thе laЬoratory synthеsisof organtс сompounds from inorgаniс starting matеrial was first асhiеvеd in thе 1820s whеn Friеdriсh \Wсlhlеrdеmonstratеd that urеa сould Ье formеd in high yiеld Ьy thе rеaсtion of сyanogеn and liquid ammoniа and Ьy hеating ammonium сyanatе. Although it was not immеdiatеly rесognizеd as suсh, a nеW еra ln сhеmiсal rеsеarсh had Ьеgun. In 1850 Adolph Strесkеr aсhiеvеd thе lаЬoratory synthеsisof alаninе from a miхturе of aсеtaldеhydе,ammonia' and hydrogеn сyanidе. This was followеd in 1861 Ьy thе ехpеrimеntsof Alеksarrdr

-t 500.сс Flask

Figurе 1. Thе appara was usеd to reprеsеn atmosphеrе.A spaгk invеntеdЬy Nikola T disсhargеsin thе atm

Тhе Оrigiп of I,ife сhеmiсal rеaсtions. During thеsе havе prеvаilеd.

ritivеЕarth ivе on thе еarth's surfaсе that it is rniс matеrial. Howеvеr, during thе .ormеdsomе 4.5 Ьillion yеafs аgo' unds prеsеnton its surfaсе Ьесausе tivе еlеmеntshеatеd thе intеrior of I roсks (.sИеthеrill1990). Volсaniс sсоrсhinggasеs out of thе juvеnilе [n addition,thе еarly еarth was also :simals,thе dеЬris lеft ovеr aftеr thе с сonvulsions,сouplеd with thе in.d surfaсе tеmpеraturеs so hot that vе had an .,oсеan''of moltеn roсk vly dесrеasеdas thе infall of oЬjесts ruptions dесlinеd,еlеvatеdtеmpеrillion yеars or longеr aftеr thе for:еmpеraturеswould proЬaЬly hаvе o s u r v i v е .W i t h o u t o r g a n i с с o m э ехistеd.Howеvеr, on thе Ьasis of геly4 Ьillion yеars ago (or pеrhaps vе сoolеd to thе point thаt liquid lЬеgin to form (Wildееt al.2001). -rpoundswould havе first startеd to ; as thеrеwеrе aЬiotiс proсеssеsЬy [atе.\ff/hatwas thе naturе of thеsе

Butlеrov,who showеd that thе trеatmеnt of formaldеhydе with alkalinе сatalysts'suсh as саlсium hydroхidе, lеads to thе synthеsisof a variеty of sugars.Thе laЬoratory synthеsisof Ьioсhеmiсal сompounds was soon еxtеndеd to inсludе morе сomplех ехpеrimеntal sеttings, and Ьy thе еnd of thе ninе. tееnthсеntury a largе amount of rеsеarсh on organiс synthеsis had Ьееn pеrformеd (Bada аnd Lazcano 2003). Howеvеr, thеsе ninеtееnth-сеntury organiс synthеsеs wеrе not сonсеivеd ..warm littlе pond'' that Darwin mеntionеd as laЬoratorysimulations of thе to Hookеr, Ьut rathеr as attеmpts to undеrstand thе autotrophiс mесhanisms of nitrogеn assimilation and СO. fiхation in grееn plants (sее Bada andLazсano 2002a).Thе first сonvinсing dеmonstration of thе possiblе synthеSisof organiссompounds undеr prеЬiotiс сonditions Was aссomplishеd in 1953 by StanlеyL. Millеr, who invеstigatеdthе aсtion of еlесtriс disсhargеsaсting for a wееk on a mixtufе of СHa, NH,, LI2' and H,o; raсеmiс mixturеs of sеvеral protеinamino aсids wеrе produсеd, as wеll as hydroхy aсids, urеa, and othеr o r g a n i сm o l е с u l е s( М i l l е r 1 9 5 3 ' 1 9 5 5 ) . Мillеr aсhiеvеd his rеsults Ьy mеans of an apparatus in whiсh hе сould simulatеthе intеraсtion Ьеtwееnan atmosphеrеand an oсеan (sееFigurе 1). As an еnеrgy sourсе Millег сhosе a spark disсhargе, сonsidеrеd to bе thе еnеrgysourсе' in thе form of lightning and сoronal disсhargеs, sесond-largеst

\r-,0", Flask

on thе Primitivе Еarth? :rе anaеroЬiсhеtеrotrophsis Ьasеd сompounds Wеrе a nесеssary prе)oratory synthеsis of organiс сom.asfirst aсhiеvеdin thе 1820s whеn ' сould Ье formеd in high yiеld Ьy n o n i a а n d Ь y h е a t i n gа m m o n i u m y r е с o g n i z е da s s u с h , а n е w е r а i n LolphStrесkеraсhiеvеd thе laЬoralf aсеtaldеhydе,ammtrnia, and hy1 Ьy thе ехpеrimеntsof Alеksandr

}сona"n,",

.r'

500-сс Flask

|10сml

Figurе1. Thе apparatususеd in thе 1953 Мillеr еxpеrimеnt.Thе 500 сс flask was usеdto rеprеsеntthе сlсеansand thе 5-1itеrflask was usеd to гeprеsеntthе A spark disсhargеgеnеratеdaсrossthе еlесtrodеswith a Tеsla сoil, atmosphеrе. invеntеdЬy Nikola Tеsla in 1891' was usеdto mimiс lightningand сorona in thе atmosphеrе. disсhargеs

5.'

56

Thе Оrigin of Lifе on thе еarly еarth aftеr UV rаdiation (Мillеr and Urеy 1959). Thе аpparatus was fillеd with various miхturеs of mеthanе, ammonia, and hydrogеn, as wеll as watеr' whiсh was thеn lrеаtеd during the ехpеrimеnt. A spаrk disсhargе Ьеtwееп thе tungstеn еlесtrodеs,wlriсh simulatеd lightnirrg atld сorona disсhargеs irr thе еarly atmosphеrе, was рrоduсеd using a high-frеquеnсy Tеslа сoil with a voltagе of 60,000 V. T,hе rеaсtion timе wаs usually a wеek or so, аnd thе nrахimum prеssurеwas 1..5Ьаrs. With this еxpеrimеntаlsеtup' Мillеr was aЬlе to transfornr alпrost 50% oI thе originаl сarЬon (in thе form of mеthanе) into organiс сompourrds.Although most of thе syrrtlrеsizеdorganiс matеrial was an irrsoluЬlеtarlikе solid, hе was aЬlе to isolаtе amino aсids and othеr simplе organiс сompounds from thе rеaсtion mixturе. Glyсinе, thе simрlеst amino асid, was produсеd tn 2Y" yiеld (Ьasеd on thе original amount of mеthanе сaгbon)' whеrеas alaninе' thе simplеst аmino aсid with a сhiral сеntеr' showеd a yiеld of \"Ь. Мillеr was aЬlе to dеmonstratе that thе alaninе that was produсеd Was a raсеtniс mixturе (еqual amounts of D- аnd L-alаninе). This providеd сonvinсing еvidеnсе that thе amino асids wеrе produсеd irr thе еxpеrimеnt and wеrе not Ьiologiсal сorrtaminants somеhow introduсеd into the appаratus. Thе othеr organiс ссlmpoundsthat Millеr was aЬlе tсl idеntify madе it possiЬlе for him to proposе a possiЬlе rеaсtion pathway for thе amino aсids (Мillеr 1957). Thе proposеd synthеtiс mесhanism wаs in faсt thе onе dеsсгibеd by Adolplr Strесkеr (18.50)whеn hе rеportеd thе synthеsisof alаninе. Тhis invоlvеs thе rеaсtion of hydrogеn сyanidе' amtnonia, arrdсaгЬonyl сompounds (aldеhydеsoг kеtonеs) to fornr amino nitrilеs' whiсh thеп undеrgo hydrolysis to form thе amino aсids (sееRеасtion 1). Dеpеnding on thе сonсеntration of аmmoniа in tЬе rеaсtion miкturе' vаr1.ingаmounts of hydroхy aсids arе produсеd аs wеll. This is what Мillеr found, with lагgеr rеlativе amounts of hydroхy асids Ьеing forпrеd in a rеaсtion tnixtuге сontаining lеss amпronia. It is important to notе that nеithеr purinеs nor pyrimidinеs, thе nuсlеoЬasеs that arе part of DNA and RNA, wеге lookеd foг iI-rthе miхturеs of thе original Millеr_Urеy еxpеrinrеnt. Howеvеr' in ехpеriпrеnts сarriеd out soon aftеr Мillеr's ехpеriпrеntЬy oro and сoworkеrs' thе formation of adеninе fronr ammonium сvanidе solutions wаs dеmonstratеd (016 1960; 016 and KimЬаll 1961). Latеr it was shown that thе abiotiс synthеsisоf purinеs аnd othеr hеtеroсyсliс сompounds аlso tаkеs plaсе undеr thе samе сonditions as in thе original Мillеr-Uгеy ехpеriпrеnr,Ьut with muсh snrallеryiеlds tharr for thе amino aсids. In additiоn' it has bееrrfourrd that guaninе сan bе produсеd in a dirесt ..onе-pot''synthеsislrсlm thе polymеrization of аquеous solr-rtionsof amпronittm сyanidе (Yuаsa еt al' 1984). AlthoLrgh thеsе rеsults аrе еxtrеnrеly еnсourаging, thе atrnosphеriс сomposition that formеd thе Ьasis of thе Мillеr.Urе1' ехpеrimеnt is not сonsidеrеd today to Ье plausiЬlе Ьy mаny rеsеаrсhеrs.It is gеnеrally аgrееd that frее oхygеn was absеnt fгom thе primitivе еаrth, Ьut thеrе is no gеnеral agrееmеnt on thе сonrposition of thе primitivе аtmospЬеrе;opinions vаry from Strongly rеduсing (СНo + N2, NI_l.r+ H,o, or Сo, + F{2 + N,) to nеutral

H(

z

/'{

O

|I

-д\ к

сy

+ HCN к

\

t+NHз

R, R'= H or CnH21*1

\

n,n

:-l

Reасtion 1. Тhе Strесker-с hydrсlхyaсids.

(СO. + N, + H,o). In gеn ward morе rеduсing сond aсids, purinеs, pyrimidirri nonrеduсn i g аrmosphеriс duсing or nеutral atmospt геnt mсldеl for thе еaгly с rе|есtеdthе idеа of nonrе numЬеr of ехpеrimеnts W( modеl atmospherеs of С( found that not only wеrс glyсinе was Ьasiсаlly thе o A gеnеral trеnd showеd t morе nеutral, thе yiеlds o: саlly, although thеy wеrе : appеаrеd to Ье еspесially i a m i n o а с i d s .T h е m a i n p r . o l o g i с а l I yr е l е v a n to r g a n i a p p а r е n tI a с k o f i o r m а t i o thе Strесkеr pathway and of nuсlеoЬаsеs (Fеrris еt i high сonсеntrations of rе( tions, and irr thеsе loсaiiz' and kеtonеs may havе Ьс сould havе Ьесomе involv Whеthег thе prinlitir'с vant with rеspесt to thе r howеvег. [t has гесеntly n i f i с а n ra m o u n t s o [ а m i n , using СO,/N'/liquid wat аmino асids found prеvrс

r '8

The Оrigiп of Lifе hydrolytiс workup Ьy nitritе and nitratе produсеd in thе rеaсtions,as wеll as Ьy thе inhiЬition of synthеsisсausеd Ьy thе low pH сonditions gеnеratеddur. ing thе ехpеrimеnt.Addition of сalсium сarЬonatеto thе systеmto Ьuffеr thе systеmnеar nеutral pH, along with oхidation inhiЬitоrs suсh as asсorЬiс aсid or Fе2n prior to hydrolysis, rеsults in thе rесovеry of sеvеral hundrеd timеs morе amino aсids than rеportеd prеviously. In thе rесеnt nеutral atmosphеrе ехpеrimеnts, thе amounts of frее сyanidе' aldеhydеs, and ammonia arе low, suggеsting that thе intеrmеdiatеs may bе Ьound as nitrilеs. Thе oЬsеrvеd amino aсids may havе formеd Ьy sеvеral mесhanisms, inсluding the Strесkеr synthеsisor thе rеlatеd Buсhеrеr-Bеrgspathway. Although thе amino aсids oЬsеrvеd and thеir rеlativе aЬundanсеs arе similar to thosе found whеn oligomеrs formеd Ьy thе sеlf-сondеnsationof HСN in aquеous solution arе hydrolyzеd (Fеrris еt a|. 1978|, thе aЬsеnсе of polymегiс matеrial in thе ехpеrimеnts аppеars to disсard this mесhanism. Ехpеrimеnts With slightly rеduсing modеl atmosphеrеs (Sсhlеsingеr and Мillеr 1983) suggеst thаt thе addition of traсеs of СHo and/or H. in nеutral atmosphеrе simulations would likеly furthеr еnhanсе thе produсtion of amino aсids. Bесausе of supposеd proЬlеms assoсiatеdwith thе dirесt Millеr-Urеy typе of synthеsеson thе еarly еаrth, а diffеrеnt hypothеsis for thе aЬiotiс synthе. sis of organiс сompounds has Ьееn proposеd. Тhis suggеstionrеsultеd from thе disсovеry of dееp-oсеan hydrсlthеrmal vеnts. A group of rеsеarсhеrshavе arguеd that thе rеmarkaЬlе propеrtiеs оf thе hydrothеrmal vеnt еnvironmеnts, partiсularly thеir protесtion from thе harsh сonditions сausеd by largе-impaсtеvеnts'might havе playеd an impоrtant rolе in thе origin of lifе. Sinсе it is thought Ьy somе that thе last сommon аnсеstraloгganism of all еxtant lifе on еагth was a thеrmophilе' sеvеral rеsеarсhеrshavе proposеd thе hypothеsis that thе organiс сompounds nесеssaryfor thе origin of lifе wеrе aсtually synthеsizеdundеr vеnt сonditions (Holm and Andеrsson 1995). Мa. joг proponеnts of this hypothеsis arе Еvеrеtt Shoсk and сoworkеrs, who havе сalсulatеd that thеrmodynamiс.ЬasеdеquiliЬria favor thе formation of сompounds suсh as аmino aсids at hydrothеrmal vеnt tеmpеraturеs(Shoсk 1990; Shoсk and Sсhultе 1998). Vеnt-Ьasеdsynthеsisis сonsidеrеd to Ье еspесially important in vеnts assoсiatеd with off-aхis systеms (Нolm and Charlou 2001; Kеllеy еt al.2001). Howеvеr, at thе high tеmpеraturеs(> 350"С) assoсiatеd with most vеnt disсhargеs,amino aсids and othеr Ьiomolесulеs havе Ьееn found to rapidly deсomposе (Bеrnhardt еt al. 1984; Мillеr and Bada 1988; Bada et a|. 1995). For ехamplе, amino aсids arе dеstroyеdin timеsсalеs of minutеs at tеmpеratrrrеsgrеatеr thаn 300.С. Thе ratе of hydrоlysis for RNA at pH 7 ехtrapolatеd to еlеvаtеd tеmpеraturеs givеs a half-lifе of 2 minutеs at 250.с for thе hydrolysis of еvеry phosphodiеstеrЬond; at 350.С thе half-lifе is 4 sесonds. For DNA, thе half-livеs for dеpurination of еaсh nuсlеotidе at pH 7 arе nеarly thе samе as thе hydrolysis ratеs for RNA (Мillеr and Lazсano 1995). lt has Ьееn pointеd out Ьy Lazсano (t997) that ifthе origin of lifе took plaсе ovеr a suffiсiеntly long pеriod of timе, all thе соmplех organiс сompounds in thе oсеan' dеrivеd from whatеvеr sourсеs' wоuld Ье dеstroyеd by passagе through thе hydrсlthеrmal vеnts. It is thus possiЬlе that

h y d r o t h е r m a Iv е n t s a r of сritiсаlorganiс mol' thеir dirесt synthеsis. D е s p i t еt h е p r о Ь l е г s y n t h е s i st h е o г y h а s b t who havе dеsсriЬеd h b i o с h е m i s t r ya n d v o l с (0.2 М) and high pгеs a v а r i е t yo f a m i n o a n d aге сonсеrns aЬout thе сhеmiсalеnvironmеn еaгth' еspесially thе l. ( B a d aе t a | . 2 О 0 7 ) .

Did Prеbiotiсorg

T h е d i f f i с u I t i е ss u p p o thеsis of amino aсids z In thе еаrly l990s Сh on thе rolе of сomеta аnd pгoposеd thаt rh с o m е t s .a n d i n t е r p l а n с a n t г o l е i n s е е d i n gt h gin of lifе. Тhis сon сompositionof mеtеo impасtsоn thе еarly е i t d i f f i с u l t f o r I i f еt o o raw mаtеrial nесеssar v i е w t h i s h y p o t h е s i sс l i f е i n t h е u n i v е r s е .T for thе origin of lifе planеt; rathеr' synthе rakеs plaсе on primit Thе possiЬilityof thе t h е е s s е n t i a lo r g а n i с t аЬlе foг furthеrсhеm С a r Ь o n а с е o u sс h o r thе most primitivе o сomposition. yеr thеу З% Ьу wеight in son o r g а n i сс o m p o u n d s i r r i a ' A u s t r а l i а )a n d M o r g u е i l m е t е o r i г е( l F CM aге aЬottt 70"Ь f grаinеd mаtеriаl. Bоt

Тhе ()rigiп of L-iiе е produсеdin tlrе rеасtions,as wеll аs thе lorv pH ссlrrditionsgеnеratеddur1 сarЬonаtе to thе system to Ьuffеr tlrе dation inhiЬitoгssuсh as asсorЬiс aсid :hе rесоvеryof sеvеral hundrеd timеs rusly. еrimеnts,thе amounts of frее сyanidе, gеstingthat thе intеrmеdiatеs may Ье сids may havе foгnrесlЬy sеvеral mесhor thе rеlatеdBtrсhеrеr-Bеrgspathway. thеir rеlаtivеaЬundаnсеsarе siп-rilarto thе sеlf.сorrdеnsation of HСN in aquе1. 1978|, thе aЬsеnсеof polymеriс ma:ardthis mесhanism. Ехpеrimеnts with Sсhlеsingеrand Мillеr 1983) suggеst r H, in nеutral atmosphеrе simulations :tion of amino aсids. :iatеdwith thе dirесt Мillеr-Urеy typе rеnt hypothеsisfor thе abiotiс syntheэposеd.This stiggеstionгеsultеd from nal vеnts.A group 350"С) assono асids аnd otl-rеrЬiomolесulеs havе rnhardt еt al. 1984; Millеr and Bada rmino aсids arе dеstro1.еd in timеsсalеs Thе аn 300"С' rаtе of hydrolysis for tеmреraturеsgivеs a hаlf-lifе of ) mirrry phosphodiсstегЬond; at 350.C thе Lalf-livеsfor dеpurination of еaсh nus thе hydrolуsis ratеs for RNA (Millеr l out Ьy Lazcano (1997) that if thе oriy long pеriod of timе' all thе сomplех vеd from whatеvеr sourсеs' would Ье othеrmalvеnts.It is thus possiЬlе thаt

vеnts аrе пruсh morе еffесtivеirr геgulating thе сonсеntratiol-t hydrothеrmal of сritiсalorgаrriсrrrtllесulеsitr thе oсеans rhirIrirr plа1,irrgа signifiсantrtllе in thеirdirесts\,'nthеsis. Dеspitеthе proЬlеms with staЬility at higli tеmpеraturеs,thе vеtrг-itlс]trсеd svnthеsis thеorу lrаs Ьееn сhampionеd lry Hrrlrеr and Wаiсhtегshiiusеr(2006), who havе dеsсriЬеdhavе ехpеrimеnts сlаimеd to ..narrow thе gap bеtrvееn and volсaniс gеoсhеrnistry.,' Usirrg high сonсеntri-rtions of HСN Ьioсhеmistry (0.2M) and high pгеssurеsof Co (7.5Ьars) in tlrе prеsеnсеof Ni/F.есatаlysts, a variеtyof amino irrrсlhydroхyl aсids arе prt>сluсесl at 100.с. Howеvеr, thеrе аrесonсеrnsaЬor-rt rеlеvanсе of this typе of tЬе ехpеrimеntto thе natural gеtlсhеmiсalеnvironnlеntsthаt w.ould Ье ехpесtеd to hlrvе ехistеd сln thе еаrlv еarth'еspесiallythе high сonсеntrаti()llsand prеssurеsof stаrtir-rgrеllgсnts ( B a d aе t a | . 2 0 0 7 ) .

Did PrеЬiotiсorganiс Сompounds Сomе from Spaсе? Thе diffiсultiеsstlpposеdly involvеd with thе еndogеnous, еаrth-Ьаsеdsl.rrthеsisof аmino aсids аnd nuсlеoЬаsеslеd to tЬе dеvеlopmеntof altеrnatir'еs' In гhееаrly 1990s Сlr1'ЬairnсlSаgan (1992| геаnirlvzеdor6's 1961 prсlposerl on thе rolе of ссlrnеtаrynuсlеi as sourсеs oi volаtilеs ftlr thе prinririvе еarth and proposеd thаt thе еxogеnous dеlivег1,of
iL)

60

Thе Оrigiп of Lifе on thе parеnt astеroid.)Thе сarЬon phasе is dominatеd Ьy an insoluЬlе fraс. tion. Thе majority (up to 80%) of thе soluЬlе organiс mattеr is madе up of polyсyсliс aromatiс hydr
PrеЬiotiс PolymеrizationProсеssеs Thе organiс mаtеrial on thе еarly еarth Ьеforе lifе ехistеd, rеgaгdlеss of its sourсе' likеly сonsistеd of a widе array of diffеrеnt typеs сlf simplе monomеriс сompounds' inсluding many that play a major rolе in Ьioсhеmistry today. How thеsе simplе aЬiotiс organiс сonstituеntswеrе assеmЬlеdinto polymеrs and thеn into thе first living еntitiеs is prеsеrrtlythе most сhallеnging arеa of rеsеarсh on thе origin of lifе. Simplе monomеrs on thе primitivе earth would nееd to undеrgo polymerization, a thеrmodynamiсally unfavoraЬlе proсеss. It is gеnеrally assumеd that polymеrs сomposеd of at lеаst20 to l 00 monomеriс units (20 to 100 mеrs)arе rеquirеd in ordеr to havе any сatalytiс and rеpliсation funсtions (Joусe 2О02; dе Duvе 200З). Thus еarly polymеrizationproсеssеsmust havе ЬееnсapaЬlеof produсing polymеrs of at lеast this minimum sizе. Thеrе is no еvidеnсе of aЬiotiсally produсеd oligopеptidеs or oligonuсlеotidеs in mеtеoritеs, so сondеnsation rеaсtions сlеarly must havе takеn plaсе dirесtly on thе primitivе еarth. Synonymous tеrms likе ..primordial Ьroth'' or ,.Dаrwin's warm littlе pond'' havе lеd in somе сasеs to major misundеrstandings,inсluding thе simplistiс imagе of a worldwidе oсеan, riсh in sеlf-rеpliсating molесulеs аnd aссompaniеd Ьy all sсlrts of Ьioсhеmiсal

monomеrs. Thе tеrm и niеnсе' rеfеrs not nесе phеrе whеrе thе aссun synthеsis may havе ta mеnts' intеrtidal zonеs going wеt.and-dry сyс

ponds. Simplе organiс сom1 iеs of watеr would nес еnhanсе polymегizatiо sorption of molесulеs r

of pгomoting polymеr: orаtory ехpеrimеnts tl vatеd monomеrs (Hill minеral-assistеdсatа1 p o l y m е r i z a t i o no f a с t i 25_50 mеr oligonuсlе еrеd nесеssaryfoг prir

Bесausе adsorptior .Waals intеraсtiоns, th polymеrization would l998; SowеrЬyеt al. .

Ьесausеas thе lеngth tеnd to Ье morе firml' pоlymеrs to Ье invoh monomеrs' thеy nееd

thе minеral' аlthough mеrs. A way around сеntratеd salt solutio tidal геgions during е

Thе dirесt сonсеntl сomplishеd Ьy еvapо tions, whiсh, сouplеr adhеrеnсе of Ьioсhеn сal сonсеntrations at rеgions and thе sut hаvе Ьееn proposеd сulеs (Nеlson еt al. j also Ьееn found to 1 2000). Thеsе samе rolе in thе synthеsis lutе solutions of aсt amounts than in еx1 25.С (Liu and orgе tесtiс frееzing is еspс сlеotidеs (Kanavario

Тllе Оrigiп o|.Liiе rhasеis dominatеd Ьy an insoluЬlе fraсrе soluЬlе organiс mattег is madе up of \Hs), аlipЬatiсhydroсarЬons' сarЬoхyliс iotta zrrrdBada 2002). Тhе purinеs adеLnthirrеhavе also Ьееn dеtесtеd,as wеll .ations
еssеs rth Ьеftlге lifе еxistеd, rеgaгdlеss of its r of diffеrеnttypеs of sirnplе monomеriс ry a mаjor rolе in Ьioсhеmistry today. Lstituеntswеrе assеmЬlеd into polymеrs s prеsеntlуthе most сhallеnging area of аrth would nееd to urrdеrgopolymеriza_ lе proсеss' It is gеnеrally assumеd tlrat )0 monomеriсunits (20 гo 100 mеrs) arе : and rеpliсаtion funсtions (Joyсе 2002; :ion prсrсеssеs must havе Ьееn сapaЬlе of rimum sizе. y produсеd oligopеptidеs or oligontrion reасtions сlеarly must havе takеn . Synon1.moustеrms likе ..primordial l . . h а v еl е d i n s o m е с a s r s t t - tm a j l l r m i s -iс inr:rgеof a worlсlwiсlе oсеan, riсlr in nparriеd Ьy all sorrs of Ьioсhеmiс:rl

monomеrs.Thе tеrm шаrm littlе poпd, wЬiсh lras long Ьееn usеd for сonvеniеnсе,rеfеrsn()t nесеssаrilyto thе еntirе oсеaп Ьut to parts of thе hydros. phеrеwhеrе thе ассumulation аrrс.lintеraсtion of thе produсts of prеЬiotiс synthеsismаy lrаvе takеrr plzrсе.Тlrеsе inсlr"rdеoсеaniс pаrtiсlеs and sеdimеnts'intеrtidalzonеs, frеshц,аtеrshallow pсlrrdsand lakеs, lagoons цndеrgoingwеt-and-dryсyсlеs, and еutесtiс еnvironmеnts assoсiаtеdwith glaсial ponds. Simplеorganiс ссlmpoundsdissolvеd in thе prirlritivеoсеаns o[ othеr Ьodiеsof watеr wсlr'rldlrееd to Ье сotlсеntratеd Ьу sotnе mесhanislrl in ordеr to еnhanсеpolyrnегizationproсеsses.Сonсеntr:rtioninvсrlvingthе sеlесtivеadsorptionof molесulеsOnto minеral surfaсеshas Ьееn suggеstеdas onе mеаns of promotingpolvmеrization' and this proсеss Ьas Ьееn dеmonstratеdin lаЬoratoryехpеrimеntsthat havе usеd a variеty of simplе сompounds and aсti_ vatеdmonomеrs (Нill еt аl. 1998; Fегris 2002). Tlrе potеntial importanсе of minеral-assistеd сatalysis is dеrnonstratеdЬy rhе montmorillonitе-promotесl polymеrizationof aсtivatеd adеnosinе and uridinе dеrivativеsthat produсеs 25-50 mеr oligonuсlеotidеs(Fеrris 2002), thе gеnеral lеngth rangе сonsid. еrеdnесеssaгyfor primеval Ьioсhеmiсal funсtiсlns. Bесausеadsoгption onto surfаrсеsinvolvеs wеаk nonсOvalеnt van dеr Waаlsintеraсtions,thе minеrаl-Ьasеdсonсеntration proсеss and suЬsеquеrrt polymеrizatiorr wсluld Ье most еffiсiеntat сool tеmpеraturеs(Liu and orgеl 1998;SowеrЬyеt al. 2001). This, howеvеr' prеsеntssomеwhat of a proЬlеm of polymегs foгmеd on miгlеral surfасеsitrсrеasеs,thеy Ьесausеas thе lеr-rgth tеndto bе morе fiгmly Ьсlund to tlrе minеral (orgеl 7998)' In ordеr for thеsе intrraсtiсlns with сltlrеrpolymеrs or polymеrsto Ье involvеd in sr.rЬsеquеnt monomеrs'thеy nееd to Ье rеlеasеd.This сoulс1Ье aссomplishеd Ьy warming thе minеral,although this would also tеnd to hydrolyzе thе adsorЬеd polymеrs.A way аround this proЬlеm would Ье to rеlеasеthе polyrnеrs Ьy сon(Hill еt al' 1998), a proсеss that сould t:rkе plaсе in сеntratеdsalr sсllr'rtions tidalrеgionsduring еvaporzrtionor frееzillg tlf sеаwаtеr. Thе dirесtсоnсеntrationof dilutе soiutiоns сlf monomеrs сould also Ье aссomplishеdЬy еvaporation and Ьy еutесtiс frееzing of dilutе aquеous solu. tions'whiсh, сouplеd with othеr physiсoсhеmiсal mесhanisms suсh as thе сould lrаvе rаisеd lo. of Ьioсlrеmiсalпlonotrrегsto aсtivе sшгf;rсеs, adhеrеnсе саl сonсеntr:rtionsаnd protrrotеd polyпrеrizzltion.Тhе еvllporation of tiсlal rеgiona s n d t h е s u Ь s е q u с n tс o n с е n t r e t i o n< l f t h е i r o r g a n i с с O n s t i t u е n r s havеЬееn proposеd in thе synthеsis of a variеty of simplе oгganiс molес u l е s( N е l s o nе t a l . 2 0 0 0 ) . Е u t е с t i с f r е е z i n go f d i l u t е r е a g е n t s o l u t i o n s h a s also Ьееn found to promotе tlrе synthеsis of kе,v Ьiomolесulеs (Lеvy еt al. p r o с е s s е sа l s o с o u l с . li r а v е p l a y е d а k е y 2 0 0 0 ) .T h е s е s a m е с O n с е l l t г i l t i ( ) n rolеin thе synthеsis of polyrrrеrs.It hаs Ьееn shown that tlrе frееzing of dilutе solutionsof aсtivatеd аmino aсids at _20.C yiеlds pеptidеs at highеr amountsthan in ехpеrimеnts with highly сonсеntratеd solutions at 0o and 25"С (Liu and orgеl 7997)' ln aсlditiсln,rесеDtstudiеs havе slrown that еu_ syllthеsisof oiigоnutесtiсfrееzingis еspесiallyеffесtivеin thе nor-rеrrzymatiс ( K a r r а v а r i o t i 2 0 0 1 ) . е t a l . сlеotidеs

61

62

Thе Оrigiп of I,ifе

dеnsе monolayеr of ioni' of pyritе. ln addition, а shаusеr amino aсid_pеpt likеly to асhiеvе format еffесtivе autoсatalysis pr

Saltу Ьrinеs mаv also havе Ьееrrimportаnt irr tlrе formаtiorrof pеpгidеs:rnd pеrhaps othеr important Ьiopolymегsas ш,еll.Aссording t
ory" (Ross 2008). Nonе of thеsе еxperill aсids arе thе еvolutionar thе rеsults arе also сoml primordial souP in whi' sourсе of еlесtrons for tI blе that undеr сеrtain g(

havе rеduсеd not only dееp-sеavеnts, and lеd l stanсе. сould havе takеr .tO?iсhtеrshlusеr 19 and N4illеr-typе a via сhargеs сеss did not rеmain Ьol surrounding aquеous еn Ьiotiс soup, not of a tw( Thе еssеntial quеstior not whеthеr pyritе-mеdi CO, rеduсtion аnd syntl

Did Pyritе Plаy a Rolе in thе origins оf Lifе on Еarth? Ft>rsomе timе, one of thе most sеriоus rivals гo thе ,.primordial soup'' hеtеrotrophiс thеory was dеrivеd frоm thе idеаs of $7;iсhtеrshziusеr (1988).Aссorсling to his ..pionееrmеtaЬoliс thеory,'' lifе Ьеgan with thе appеaranсеоf аn aLltoсatalytiсtwo-dimеnsiotr:rlсhеmоlithorrophiс mеtaЬсlliс systеm that took plaсе on thе surfaсеof thе highly insoluЬlе minеral pvritе in thе r,iсiniry of hydrothеrmal vеnts.Rеpliсation followеd thе appеaranсеof this nonorgan. ismаl iron sulfidе*Ьasеdtwo-dimеnsi
pothеtiсal two.dimеnsi< Proof of Wiсhtеrshiusе tight сoupling of thе rеа t i o n v i a а r е d u с t i v ес i t r i of homologotls сyсlеs th wеll as rеpliсation (Мaс

imеntal геsults aсhiеvеd and Co arе сonsistеnt ! thе rolе of sцlfur-riсh п mulation of organiс сor

Ьееп shown to providе an еffiсiеnt sourсе tlf еlесtrons for thе rеduсtiсln of organiс сompounds undеr mild сonditions. Pyгitе formation сan produсе mol е с t r l a rh y d r o g е n : r r r dr е d u с еп i r r a t еt o a m m < l n i aa, с е t y l е n ег < еl t h y l е n е ,a n d thioасеtiс асiс.lttl aсеtiс aсiсl, .rs wеll as L)гolrrotingmorе сomplех syDthеsеs (Мadеn 1995), inсluding pеptldе Ьсlnds thаt геsult fronr thе aсtivatioп of amino aсids with сarЬon monохidе and niсkеl/iron sulphidеs (HuЬеr and \й/dсlrtеrshiusеr1998). Although pyritе-mеdiirtеdСO, rеdLrсtionto orgаtriс сompour-rdshas not Ьееn aсhiеvесl,thе fiхatiсlп undеr plzrusiЬlepгеЬi
How Did Rеpliсati

Thе pгimordial Ьroth r dеrland in whiсh a wid sizеd' dеstroyеd, or in Rеgardlеss of thе сoпrp сould not havе еvolvеd guarantее thе maintеnl Ponеnts undеr thе aсt molесular еntitiеs сa] would hаvе markеd tl

: 5

Тhе Оrigiп of Life oгtаntin thе formation сlf pеptidеs and rs wеll. Aссording to Rodе and сoworkэ formatiоn rеасtion'' (SIPF)provides a pеptidеsand possiЬly protеins dirесtly ltеd NaСl solutions сontaining Сu(II). gе of 0.4 to 4oЬ Ьaуe Ьееn rеportеd us; in thе 40_50mМ rangе. Сlay minеrrtly promotс thе rеaсtion. Again, thе o r t h е f г е е z i n go f t h е p г i m i t i v еo с е a n 5 salt.riсhЬrinеsnееdеdto promotе this

)riginsof Lifе оn Еarth? rs rivals to thе ..primordial soup'' hеt. еi d е a so f W i с h t е r s h i u s е r ( . l 9 8 8 ) .A с lry,'' lifе Ьеganп,ith thе appеаranсе of molithotrophiс mеtаЬoliс systеm that insoluЬlеminеral pyritе in thе viсinitу owеd thе appеaranсеof this nonorgannal ..lifе,''in whiсh сhеmoаutotrophiс :tivесitriс aсid сyсlе, or rеvеrsе KrеЬs Or thе photosynthеtiс grееn sulfr.rrЬaсlar phyiogеnеtiсtrееs show that this fiсations(suсh аs thе rеduсtivе aсеtyl)athways)аrе found in anаеroЬiс ar:uЬасtеria'whiсh has Ьееn intеrprеtеd Madеn 1995\. But is thе rеvеrsе KrеЬs , is vеry еnеrgеtiсallyfavorаЬlе. It has ]tеrWith а stаndard frее еnеrgy сhangе sponds to a rеduсtion potеntial Е., = tion is a strongrеduсing agеnt and has :сеof еlесtronsfor thе rеduсtion of orns. Pyritе formаtion саn produсе mol ammonia, aсеtylеnеto еthylеnе, and ts promoting morе сomplех synthеsеs rds that rеsult from thе aсtivation of rnd niсkеl/iron sulphidеs (HuЬеr and tе-mеdiatеdСo, rеduсtion to organiс hе fiхation undег plausiЬlе prеЬiotiс :tivatеdaсrtiс aсid Ьy a miхturе of сolortеd (HuЬеr and $7гiсhtеrsh:iusеr thе rеaсtionsсlссur in аП aquеOus еnhas Ьееn аddеd: thеy d
dеnsеmonolayеr of ioniсally Ьound molесulеs or takе plасе on thе surfасе of pyritе.In addition' a сarеful ехaminatiorr of thе HuЬеr and !Иziсhtеrshiusеramino aсid-pеptidе synthеsissсhеmе hаs found that it is highly un. likеly to aсhiеvе formation of oligomеrs that had thе aЬility to promotе ..pionееrmеtaЬoliс thееffесtivе аutoсatalysisproсеssеsassoсiatеdwith thе o r y " ( R o s s2 0 0 8 ) . Nonе of thеsееxpеrimеnts provеs Ьy itsеlf that Ьoth еnzymеs and nuсlеiс aсidsarе thе еvolutionary outсomе of surfaсе-ЬoundеdmеtaЬolism. In faсt, thе rеsultsarе also сompаtiblе with a morе gеnеral' modifiеd modеl of thе primoгdial soup in whiсh pyгitе formation is rесognizеd as an important sourсеof еlесtronsfor thе rеduсtion of organiс сompounds. It is thus possiЬlеthаt undеr сеrtain gеologiсal сonditions thе FеS/H,S сombination сould havеrеduсеd not only Сo Ьut also СO. rеlеasеd from moltеn mаgnа in dееp-sеavеnts, and lеd to Ьioсhеmiсal monomеfs. Pеptidе synthеsis' for instanсе,сould havе takеn plaсе in an iron and niсkеl sulfidе systеm (HuЬеr and Wiсhtеrsh:iusеr 1998) involving amino асids formеd Ьy еlесtriс disсhargеsvia a Millеr-typе synthеsis.If thе сompounds synthеsizеdЬy this pro. сеssdid not rеmain Ьound to thе pyritе surfaсе Ьut driftеd away into thе surroundingaquеous еnvironmеnt, thеn thеy would Ьесomе part of thе prеЬiotiсsoup, not of a two-dimеnsional autoсatalytiс rеaсtion sсhеmе. Thе еssеntial quеstion in dесiding Ьеtwееn thеsе two diffеrеnt thеoriеs is not whеthеr pyritе-mеdiatеd organiс synthеsis сan oссLlr' Ьut whеthеr dirесt Сo, rеduсtionand synthеsisof organiс сompounds саn Ье aсhiеvеd by a hypothеtiсal two-dimеnsional living systеm that laсks gеnеtiс information. Proof of !7ziсhtеrshiusеr's hypсlthеsisrеquirеs dеmonstration not only of thе tightсoupling of thе rеaсtions nесеSsаryto drivе autoсatalytiс СO, assimilationvia a rеduсtivесitriс aсid сyсlе Ьut also of thе intеrwеavingof a nеtwork of homologousсyсlеs that, it is assumеd,lеd to all thе anaЬoliс pаthways' as wеll as rеpliсation (Мadеn 1995). This has not Ьееn aсhiеvеd.ln faсt, ехpеrimеntalrеsults aсhiеvеd so far with thе FеS/H,S сomЬination in геduсing N. and Сo arе сonsistеnt with a hеtеrotrophiс origin of lifе thаt aсknowlеdgеs thеrolе of sulfur-riсh minеrals аnd othеr сatalysts in thе synthеsisand aссumulationof organiс сompounds.

How Did Rеpliсation First originatе? Thе primordial Ьroth must havе Ьееn a Ьеwildеring organiс сhеmiсal wondеrlandin whiсh a widе array of diffеrеnt molесulеs Wеrе сonstantly synthеsizеd,dеstroyеd' or inсorporatеd into сyсlеs of сhеmiсal transformations. Rеgardlеss of thе сomplехity of thе prеЬiotiс еnvironmеnt' lifе as wе know it сouldnot havе еvоlvеd in thе aЬsеnсеof a gеnеtiс rеpliсating mесhanism to guarantееthе maintеnanсе,staЬility' and divеrsifiсation of lifе's Ьasiс сomponеntsundеr thе aсtion of natural sеlесtion. Thе appеaranсе of thе first molесulаr еntitiеs саpaЬlе of rеpliсation, сatalysis' and multipliсation .What wеrе thе would havе markеd thе orisin of Ьoth lifе and еvolution.

o.)

64

The (.)rigiпof Lifе furrdamеntalсhаraсtеristiсsof thеsе first mсlIесr-rlar living еntitiеsthat distinguishеd thеrт fr
thе PNA-RNA and P] pеaling as possiЬlе сar titiеs, both PNA and nеgativе faсtors arе t that would prоduсе t сonditions and thе laс PNA is attraсtivе l whiсh еliminatеs thе r origin of lifе. Its сorn havе Ьееn produсеd ur Howеvеr, PNA is susс rеarrangеd PNA. Thil thе N-tеrminal positiс on thе Ьasis of an Pеars to Ье supеrior t. to its Ьasе-pairing attr Sсhсiningеt al. 2000). during thе rеaсtion сa dеsсriЬеd Ьy Butlеrov сould havе bееn rеad (sееRеaсtion 2), whiс tion of formaldеhydе. rеduсеs this proЬlеm oligonuсlеotidеs сom1 sizеd undеr prеЬiotiс r It is possiЬlе that P] to thе fiгst TNA molе сomponеnt of TNA w in opеrаtion. orgе1 aI сhiral sugar dinuсlеot сurrеd simply Ьy сhan PNA.induсеd oligom. providеd а mеans of с сhirality into polymеr tеntially solvеs an onf Ьеforе thе origin of lil

I{снo

нснo ..--..---.-.--f

Formaldehyde

G.

Reасtion 2. Тhе forma formaldehydeand glyс of rеaсtions'and Ьoth suЬsеquеntгеaсtions.

The Оrigiп of Life irst molесulаr living еntitiеs that distinry? rеrs аnd smali oligomеrs to living еntithе uЬiquit
thе PNA-RNA and PNA-DNA hеliсеs arе both right-handеd. Although appеalingas possiЬlесandidatеsfor thе first sеlf-rеpliсatingmolесular living еntitiеs,Ьoth PNA and TNA havе positivе and nеgativе aspесts. Thе main nеgativеfaсtors arе thе laсk of аny dеmonstratеd oligomеrization proсеss that would produсе thеsе nuсlеiс aсid analоguеs undеr plausiЬlе prеЬiotiс сonditionsand thе laсk of any dеmonstratеd сatalytiс propеrtiеs. PNA is attraсtivе Ьесausе its ЬaсkЬonе is aсhiral (lасking handеdnеss), whiсh еliminatеsthе nееd for thе sеlесtion of сhirality Ьеforе thе timе of thе origin of lifе. Its сomponеnts, AЕG and nuсlеoЬasеs linkеd to aсеtiс aсid' havеbееnproduсеd цndеr simulatеd prеЬiotiс сonditions (Nеlson еt al. 2000). Howеvеr'PNA is stlsсеptiЬlеto an N-aсyl migration rеaсtion that produсеs a rеarrangеdPNA. This proЬlеm сould Ье minimizеd, howеvеr, Ьy Ьloсking thеN-tеrminal position Ьy асеtylation' for еxamplе. on thе Ьasis of an ехtеnsivеstudy of sugar-Ьasеdnuсlеiс aсids' TNA appеafsto bе supеrior to othеr possiblе sugar-Ьasеd nuсlеiс aсids with rеspесt to its Ьasе-pairingattriЬutеs,еspесiallywith RNA (Еsсhеnmosеr1999, 20041 Sсhбningеt al. 2000). Thе tеtrosеsugar in TNA сould havе Ьееn synthеsizеd duringthе rеaсtion сasсadе that takеs plaсе during thе formosе rеaсtion first dеsсriЬеdЬy Butlеrov in 1861. Thе 4-сarЬon sugars thrеosе and еrythrеosе сould havе Ьееn rеadily synthеsizеd Ьy thе dimеrization of glyсolaldеhydе (sееRеaсtion2), whiсh in turn сould havе Ьееn produсеd from thе dimеrization оf formaldеhydе. Еvеn though thе prеsеnсе of a 4-сarЬon sugаr in TNA rеduсеsthis proЬlеm to 2 sugars and 4 stеrеoisomеrs' to dеmonstratе how oligonuсlеotidеsсomposеd only of L-thrеosе сould Ье prеfеrеntially synthеsizеdundеr prеbiotiс соnditions is a formidaЬlе сhallеngе. It is possiЬlе that PNA prесеdеd TNA and in faсt assistеd in thе transition to thе first TNA molесulеs. As statеd еarliеr, thе sеlесtion of thе сhirаl sugar сomponеntof TNA would havе rеquirеd somе sort of sеlесtion proсess to Ье in opеration. orgеl and сoworkеrs havе suggеstеd that thе inсorporation of сhiral sugar dinuсlеotidеs at thе еnd of a PNA сhain' whiсh сould havе oссuгrеdsimply Ьy сhanсе, сan induсе сhirality into a nuсlеiс aсid produсеd Ьy PNA.induсеd oligomеrization (Kozlov еt al. 2000). PNA сould thus havе providеda mеans of сonvеying thе сritiсally impоrtant Ьiologiсal propеrty оf сhiralityinto polymеrs nеar thе timе of thе origin of lifе. This possiЬility potеntiallysolvеs an ongoing dilеmma whеthеr thе origin of сhiгality oссurrеd Ьеforеthе origin of lifе оr during thе еvolution of еarly living еntitiеs.

tlснo

HCНo'нoсн?-сHo

Formaldehyde

н9SЦr91o ЕIoсн2-сFIoH.Co-CH2oH

Glyсolaldеhydе

Reaсtion2. Thе formation of tеtrosеsugars from thе dimеrization of and glyсolaldеhydе.This is оnly part of the ovеrаll formosе sеriеs formaldеhydе and ЬotЬ hеxosеsаnd pеntosеswould havе Ьееn produсеd Ьy of reaсtions, rеaсtions. subsеquent

Тhе ()rigitt оf 1,ifе Rеgardlеssof thе typе of analoguе simiIar to nuсlеiс aсid or othеr typе of rеpliсator sуstеm that wаs usеd Ьy tl-rеfirst self-rеpliсatingеntitiеs, polvmеr staЬility and survival would havе Ьееn of сritiсal importanсе. Nuсlеiс aсidsin gеrrеralhаvе vеry shсrгtsurvival timеs at еlеvatеdtеllpеraturеs. RNA is r,еrу Ьond involvirtgthе 2'unstablе Ьесausеof thе prеsеnсеof thе phсlsphсldiеstег Ьydroхyl group of riЬоsе. Thе staЬiIiryof TNA is unkrrorvnat prеsеnt' Ьut it is proЬaЬly somеwhаt similar to thе staЬility of DNA. It is possiЬlеtlrat otlrеr tеtrosе sugar-Ьasеdnuсlеiс aсids wеrе lеss staЬlе thirn TNA Ьесаusеof thеir tеndеnсy ttl forш lеss staЬlе hеliсal stfrrсtul]еs(ЕsсЬеnmtlsеr|L)99|аrrd tlrаt thе sеlесtion of TNA Was thе rеsult of this faсtсlr,althotlgh this is also not known. Tlrе stаЬility of PNA lrаs Ьееn pаrtly invеstigatеd,and providеd thе N-aсyl migration rеaсtion сan Ье rninimizеd, thе аmidе linkagе in PNA rvould Ье еxpесtеdto havе a staЬilitу at nеutral pH similar to that of pеptidе rvith tеmhonds in prno.,di-' аnd triglусеridеsur-rdегrтild ссlnditions (Hargrеavеsеt аl. 1977)' It is vеry atrraсtivеtO assulте thаt сorтpartmеntalization within liposot-llеsformеd Ьy amphiphiliс molесulеsof prеЬiotiс origin асlsorЬеdorltо сlaуs \vаs еssеntiillfor thе еmеrgеnсеof lifе. RNA nr
thе Ьasiс maсhinеry . partmеntalizеd into Dеspitе thе suссеsl ..with lеms with this ordеr to maintain a s сating systеm insidе layеr barriеr. This г as amino aсids. As a sidе thе vеsiсlе'' (Gr surfасеs сould havе сules that usеd thе сz volvеd in polymеrizа сomplеxity, synеrgis of thе сomponеnts il portеd into thе vеsiс formеd a singlе сom rеsults showing that сomе polymеrizеd ч pidiс Ьarriег may no

Thе Transition l

Thе еvolution of thс tirеly on RNA (i.е. еvolution toward m< onе molесulе that са ..t LaЬoгatory-basеd сatalytiс RNA molе rangе of important RNA fragmеnts (lig

1999|. Thе list of dt that thе RNA world есulеs, pеrhaps funс 2002). Thе сomplеx tiс transfеr, аnd vaI dеmonstratеd in thе immatuгity of tlris Cесh 2002; Joусe2| Thе invеntion of сhinегy nееdеd for l Four of thе bаsiс rеа Ьozymеs, and it has tions is not likеly a oгigin, most prоЬaЬ thе сasе' thеn thе рr

Thе Оrigin of Life similar to nuсlеiс aсiсl or othеr typе of е 6rst sеlf-геpliсаringеntitiеs' pthеr lеss staЬlеtharrТNA Ьесausеof rhеir rllсturеs(Еsсhеnmosеr1999) and tlrat lf this faсtor, altЬough this is also not l pагtly invеstigatеd,and providеd thе 'inirnizеd' thе amidе lirrkagе in PNA tt nеutrаlpH sinrilar to that of pеptidе uggеststhat in еnviгonmеntswith tеmtiпlе would Ье in thе rangе of 101_105 rolе in еarly nuсlеiс aсid survival Ьеэеn found to еnhanсе nuсlеiс aсid stаsеvеrаltransfеr RNAs (tRNAs) wеrе solution in сompzrristlсliрidiс molесr-rlеs mаv als
thеЬasiсmaсhinегуnееdеd for RNA sеlf-rеpliсatiсlnсould hаvе ЬееIrсomirrto pгoto-typесеils (Наriсzyс еt :rl.200З; Сhеn 2006). pаrtmеntalizеd Dеspitеthе suссеssof thе RNA еnсapsulatioIrехpеrimеnts,thеrе arе proЬ..rvithin lеmswith this thе vеsiсlе'' sсеnario (Griffiths 2007). For ехаmplе, in ordеrto maintain a stеаdy supply of molесulеs nееdеd for survival of a rеpliсatingsystеminsidе a vеsiсlе, molесulеs would nееd to сross a lipid-likе ЬilayеrЬarriеr'This rrlay havе Ьееn а mirjor oЬstaсlе foг сhargеd spесiеs suсh ..outas aminoaсids.As a rеsult' pеrlrirpsthе first rеpliсating systеm еvolvеd sidе thе vеsiсlе'' (Griffiths 2007). In this сasе, vеsiсlеs attaсhеd on minеral surfaсеsсould hаvе Ьееn in сlosе proхimity to sirnplе sеlf-rеpliсating molесulеsthat usеd thе сatalytiс propеrtiеsof thе minеrаl to еnhanсе rеaсtions involvеdin polymеrizationand rеpliсаtion. As thеsеtlrе two systеmsеvolvеd in сomplехity,synеrgistiсintеrirсtiotrsсould iravе dеvеloреd thar аllсlwеd somе of thесomponеntsinvolvеd in thе rеpliсating systеm to Ьесomе frееly transportеdinto thе r,еsiсlе.At this point thе two systеms сould havе rrrеrgеdand formеda singlе сomрartmеntalizеd, sеlf-rеpliсation systеm. Howеvеr, rесеnt rеsultsshowing thаt aсtivatеdnuсlеotidesсan diffrrsеinto liposomеs and Ьесomеpolymеrizеdwithin thеm suggеstthаt undеr сеrtain сonditioпs tl-rеlipidiсbarriеrmаy not havе Ьееn irnpеnеtraЬlе(Маnsy еt al. 2008).

Thе Transition toward a DNA/RNA/Protеin

World

Thе еvoiutionof thе first livirrg rrrolесularlir,ing еrrtitiеsinto onеs basеd еntirеlyon RNA (i.е.,thе RNA rvоrld) would lravе Ьееn thе nехt stеp in thе еvolutiontoward modеrn Ьiосhеrnistry.RNA has Ьееn found to Ье an all-inonеmolесulеthat сan not only storе information Ьut also сatalyzе rеaсtions. ..tеst-tuЬе-еvolution'' ехpеrimеtrtshavе dеmonstгatеdthat LaЬoratory-Ьasеd (riЬozyrnеs) havе thе саpасitv to сaгry Out a widе сatаlytiсRNA molесulеs rangеof iпrportant Ьioсhеnriсal геaсtions,irrсluding thе joining togеthеr of RNA fragmеnts (ligation) and pеptidе-Ьond formation (Bartеl and Unrau 1999).TЬelist of dеmonstratеdсatalytiс rеaсtions is ехtеnsivе aпd suggеsts thatthе RNA world сould havе had a lаrgе rеpеrtoirеof сatalytiс RNA mol. in сonсеrt with onе an()thеr(Doudna irnd Cесh есulеs,pеrhаps fr"rпсtiоning rnultipliсаtion'gеnе2002).Thе сotrrplехsеriеsof rеасtionsnееdеdto pеrr-r.rit tiс transfеr,and variation rеqr.lirеdin thе RNA wоrld has so filr not Ьееn in thе laЬoratсlry,Ьut optimism rеlrrainsbесausеof thе rеlativе dеmonstratеd immaturityof tЬis arеa of rеsеаrсh (Bartеl аnd Unrau 1999; Doudna and Сесh2002;Joyсе 2002). Thе invеntion сlf protеin synthеsisand thе еnсаpsulation of rеасtioll maсhinеrynееdеd for rеpliсation n1аy have takеn p[асе during thе RNA world. Fourofthе Ьasiс rеaсtitlnsinvolvеd in protеin Ьiсlsynthеsisarе сatаlyzеdЬy riЬozymеs,and it has Ьееn notеd that thе сomplеmеntary naturе of thеsе rеaсtions is not likеlv aссidеntal Ьut rathеr suggеstivе that thеy had a сommon origin,most proЬably in thе RNA wсlrld (Kumar atrс]Yarus 2001)' If this was thесasе,thеrrtlrе primitivе nltсlеoЬasесodе usеd tor protеin Ьiosyntlrеsislrad

67

Thе Оrigiп сlf l,ifе its origin in thе RNA worlсl, аlthough thе b:rsеsusеd in thе early сodе сould hаvе Ьeеn diffеrеrrtfгorn tllе onеs usесJtodаy (KolЬ еt аl. 1994). It is possiЬlе thаt Ьy thе timе RNA-Ьasеd lifе appеaгеd
Did Lifе Arisе in a High-TеmpеraturеЕnvironmеnt? Еvеn tlrouglrDNA is nrorе st:rЬlеthan RNA, it is still rарidly dеgrаdеdat еlеr,atеd tеmpеraturеs.In addition, Protеin еnzymеs dеnaturе rapidly at еlеvatеd tеmpеraturеs.This rтtrsthаr,еat lеаst irtitiаllylimitеd thе еnr,ironmеntswhеге DNA/protеin-Ьasеd lifе сould survivе for anr. signifiсzrntpеriоd of timе, аnd as was thе сasе for аll othеr еarliег living еntitiеsЬаsеd tln nuсlеiс aсid, sr.lrvivаl would havе Ьееn most likеly undег сool сonditiorrs(Bаda and [,azсаno2002Ь). Nеvеrthеlеss, sevеral rеsеarсhеrslravе advoсatеd high tеп1pеraturеs,еspесiаllу thosе zrssoсiatеdrvith [rydrсlthеrnralvеrrt systеnrs,as thе еnr,ironmеnt whеrе DNA/protеin_Ьasеd еntitiеs first аrosе. Prсlponеntsfor а high.tеmpеrаturеOrtgin сitе thе f:tсtthаt thе trnivеrsаltrее сlf ехtаI1tlifе irppеаrst
Pеrthеrmophiliс organt modеrn Ьiology was a DNA/protеin-Ьasеd lift At first glanсе, Ьoth аPPеаr to support a }

еarly. Largе-sсalе anal of primitivе еarth was rrmainеd moltеn for (Nfеthеrill 1990), but n hydrosphеrе impliеs th Howеvеr, thеrе is thес wеnt latе ассrеtion im. may havе Ьoilеd thе oс Could modеrn bioсh ditions? Thе proposals lеms, inсluding thе сhе сompounds suсh as ar molесulеs, whosе ha] 250_350.с arе at thе n

It is truе, of сoursе, fаstеr. Primitivе еnzyI аnd thus thе ratе еnha: onе way to ovеrсome rizеd еlsеwhеrе (Islasi

1. rеduсеd сonсеntr and NH.; 2. lowеr Stеady.stat whiсh at tеmpеra fоrmamidе and tl 3. instability of rеaс

(RсFIo(Nt{,)СЬ

o f a m i n o a с i d s ;a 4. loss of organiс сс s t a Ь i l i t yo f g е n е t

Thе rесognition thz arе oссupiеd Ьy hypе itsеlf сonсlusivе proо lifе (Broсhiеr and Phi sсriptions of thе еvo bioсhеmiсa1сompoul bly nаivе to attеmpt living systеms from п еrаl gеnеtransfеrof. misеd thе gеnеtiс rе сonсlusions aЬout th.

Tbe Оrigiп of Li|.е r thе Ьasеsusеd in thе еarly сodе сoLlld ltodаy (KolЬеt aI.1994). -Ьаsеdlifе irppеarеdOn еartЬ' thе suprnds dеrivеdfrom tЬе sourсеs disсussеd ishеd.М:rrryсlf thе сomporrеnts of thе sivеly сonvеrtеdintrl polymеrs, inсluds, and thus thе rаw mаtеrials neеdеd to tеd.This irrrpliеsthat simplе mеtаЬoliсе in ordеr tO еnsurе a supply of thе inсе oi thе prinlitivеlir.ingеntitiеs.In this iеd to produсе еssеntial сtlnrponеnts - ' r е1 . l е r l i д pt lqr i g i n l I l r n o n е n z v m a t i сo r rlratiatеr Ьесamеfinе гurrеdаs riЬozyoсеssingЬесamеdominаnt. ulаг еntities,thе main limitаtiоn irr thе rеrnеinstaЬility of RNA. Tlris in tr'rrn r v е Ь е е n v е r y е Г f i с i е n ri n с з r r y i n g < l u t rаintainan асlеquatеitlvеntorr.of mol'ility of RNA сould havе Ьееn thе pгi)NA/pгotеirr world, whеrе, Ьесausе of olесulеs,suгl,ir'aIlr'сluldh:rl'еllееn lеss dirrgto.|oyсе(2002), it is p
еrаturеЕnvironmеnt? RNA, it is still rapidl1'dеgraсlеdat еlеn еnzymеsdеnаturегapidly аt еlеvatеd ritially limitеd thе еnvironmеntswhеrе lг any signifiсаntpеriod of tiлlе, and аs еntitiеsЬasеdon nr.rсlеiсaсid, survival сonditions(Badaand I,аzсаno20O2Ь). dvoсаtеdlriglr tеnlpеraturеs,еspесi:rlly nt systеms'as thе еnvironmеnt whеrе P r o p о n е n t Гs o rl h i g , h - t е m p е г а t urrlеr i Еехtаnt litЪ appеars to Ье ro
pеrthеrmophiliсorganisms. Thus if thе lаst сomп]on anсеstor (LСA) of all modеrnЬiоlogy was a hypеrthеrmоphilе, thеn it is сonсluded that tlrе first DNA/protеin_Ьasеdlifе nrust havе arisеn in a similar typе of еnvironmеnt. At first glanсе' Ьoth thе molесular and thе palеontologiсal fossil rесords appеarto support a lrypеrthеrпrophiliсorigin of lifе. LitЪ on еarth arosе еarly.Largе-sсalе analysis suggеsts that soоn aftеr its formation thе surfaсе of primitivееаrth was еxtrеmеlу hot. Thе planеt is gеnеrаlly thouglrt to havе rеmainеdmoltеn for somе timе aftеr its formation 4.6 Ьillion yеars ago (Wеthеrill 1990|, Ьut minеralogiсal еvidеnсeof a 4'З- to 4'4-Ьillion- yеar-old lmpliеs that its surfaсе гapidly сoolеd down (\Уr'ildе еt al. 2001,). hydrosphеrе Howеvеr,thеrе is thеorеtiсal and еmpiriсal еvidеnсе that thе planеt undегWеntlatе aссrеtion impасts (Byеrly et a|.2О02; Sсl-roеnЬеrg еt al. 2002) that yеaгs (Slееp latе еt aL.|989). mayhavеЬoilеd thе oсеans as as 3.8 Ьillion ago Сould modеrn Ьiосhеmistry havе arisеn undеr thеsе high tеmpеrаturе сonditions?Thе proposаls of a high-tеmpеrаturе origin of lifе faсе major proЬlеms'inсluding tlrе сhеnriсal dесomposition of prеsumеd еssеntial Ьioсhеmiсal сompoundssuсh as amino aсids, nuсlеoЬasеs, RNA, and othеr thеrmсllaЬilе molесulеs,whosе half-livеs for dесomposition at tеmPеraturеs Ьеtwееn 250-350"Сarе at thе most a fеw minutеs (!(/hitе1984;Millеr and Bada 1988). It is truе' of сoursе' thаt high tеmpеraturеsаllow сhеmiсal rеaсtions to go fasrеr.Pгimitivе еnzymеs' onсе tlrеy appеared, сould hаvе Ьееn inеffiсiеnt аndthus thе ratе еnhanсеmеnt аssoсiatеd with highеr tеmpеraturеs wouid bе onеWay to ovеrсomе this limitation (Harvеy 1924), Howеvеr, аs summarizеdеlsеwhеrе(Islaset a|.20О7)' high-tеmpеraturеrеgil-tlеs would lеad to: 1.rеduсеdсonсеntratiOnsof volatilе intеrmеdiatеs'suсh as HСN, H2СO, and NH,; 2. lowеr stеady-statесOnсеntrationsof prеbiоtiс prесursors likе HСN' whiсh at tеmpеraturеsa littlе aЬovе 100.С undеrgoеshydrolysis to first forrnamidеаnd thеn formiс асid arrd ammoniа; 3. instabilityof rеaсtivе сhеmiсal intеrnrеdiatеslikе amino nitrilеs (RсHo(NH')сN), whiсh play a сеntгal rolе in thе Strесkеr syr-rthеsis of amino aсids; and 4. loss of оrganiс сompounds Ьy thеrmal dесomposition and diminishеd staЬilityof gеnеtiс polymеrs. Thе rесognitionthat thе dееpеstЬranсhеs in rootеd univеrsal phylogеniеs arеoссupiеdЬy lrypеrthегrnophilеsis сontrovеrsiаl and doеs not providе Ьy itsеlfсonсlusivеproof of a higlr.tеmpеraturеorigin of DNA/protеin-Ьasеd lifе(Broсhiеrand Рhilippе 2002). Givеn thе hugе gap еxisting in сurrеnt dеsсriptionsof thе еvoltrtionarytransition Ьеtwееn thе prеЬiotiс syr-rthеsis of Ьioсhеmiсalсorrrpounds and thе LСA сlf аll ехtarrt living Ьеings, it is proЬаЬly naivе to attrmpt to dеsсriЬе thе origin of lifе аnd thе naturе of thе first livingsvstemsfronr nrolесularplrylogеniеs(Islaset aI. 2007).In addition, lаtеralgеnеtransfеr of thеrmoadaptativеtrаits has apparеntly grеаtly сompromisеdthе gеnеtiс rесord prеsеnt in modеrn organisms, r,vhiсh makеs any сoпсlusions aЬoцt thе еnvironnrеntwhеrе thе DNA/protеin world origirrаtеd

69

70 Тhc Оrigilt of I'ifе q t l е s t i o n a Ь l е( D o o l i t t l е | 9 9 9 , 2 О 0 О 1B е с е г r a е t a l . 2 0 0 7 Ь ) . A r r a n a l y s i so f protеin sеqtlеIlсеshаs f
From thе Origin of Protеin Synthеsistо thе Last Сommon Anсеstor оf Lifе Orrсе DNA/pгotеin_Ьlrsеdlifе, аnd proЬaЬly RNA-Ьаsеd lifе as wеll, Ьесarте dorтinant and еvolvеd in stlphistiсatitln,thе way сarЬon was produсеd аnd оrr thе еаrth,ssurfасе was foгеvеr сhangеd' еspесiallу aftеr phosес1uеstеrеd tosynthеsiseppеarесl.Thе amor.tntof organiс сarЬon produсеd Ьy еaгl1 lifе via the аutotrophiс fiхation of СС),' СН,,, and simplе organiс сompounds suсh as fornriс and :rсеtiсасids rvоuld havе far ехсееdеdthе anr
extant forms of lifе Ьut Ponеnts of thеsе сom; сhangеs in thеm arе vt that no anсiеnt inсipiеr ular struсturеs havе bе сan Ье dеduсеd, аnd th

fаshionеd and сontеm1 For instanсе, thе faсt forming all thе rеaсtion еаrliеr, that protеin Ьiс 1998), that is' that thе 1

RNA. This possibiliry thаt thе ribosomе's сatl сomposеd of RNA (Bar

ganization of primitivе gеnеs, whiсh arе sеquеr pliсadon еvеnt. Foг ins1 gous gеnеs that еnсoс triphosphatе)-dеpеndеr

еvidеnсе of thе ехistеn synthеsis that took plа mеntal еvidеnсе of in ' trations laсking Ьoth (Gаvrilova et a|.1976;

anсеstral protеin syntht Bioinformatiс analy domains сan bе usеd t sеquеnсеs to сharасtеr rеsulting sеt is dominа volvеd in gеnе еxprеss whiсh unwind RNA r сonsеrvеd as many tra еvolution of a сontrol viding additional suPP prominеnt rolе during biosynthеtiс pathway rophosphatе synthasr taЬolism. Although t сorrеsponds only to а poгtеd hеrе are likеly protеin domains сoml Thе high lеvеls of imply not only that r

thе сomplеx Bеnomе dupliсation еvеnts rе. tion is usеd tо Ьuild

Тhе origiп of Lfе B е с е r r aе t а l . 2 0 0 7 Ь ) . A n a n a l y s i s o f : еnzуmе'[еvеrsеg},rаsе'that is sресifiс ]rе appаrеntlynot аnсеstralto thеsе orJ-adaptеdvеrsions of thosе prеsеnt in r е 2 0 0 2 | .Е v е n i f t l r е L С A w a s a h y p е r ,uyand Сhaussiсlorr2008), thеrе arе illl distriЬution,inсluding thе possiЬility hеanhigh-tсrnpеraturе rеgimеsthat may lпе (Slееpеt al. 1989; Gogаrrеl-r-Boеkels гia to ехtrеmе еnr,iгonmеntsЬy latеrаl al. 2000) and otЬеr thеrmoadаptativе (3) outсornpеtionof oldеr nrеsophilеs )tеdto strеss-indr-rсing сonditi
nthеsisto thе Last oЬaЬly RNA-Ьasеd lifе as wеll, Ьесanrе tln, thе way сarЬon was produсеd and s forеvеrсhangеd,еspесiаlly аrftеrphoorganiс сarЬon prоduсеd Ьy еarly lifе СHo, and simplе organiс сtlmpounds ] havе fаг ехсееdеdthе amouгtts of orЬеirrgsynthеsizесl'fгom еithеr hornе. ourсеs undеr thе Ьеst сonditions. Thе on thе еаrth thеn shiftеd frorn onе ini. aЬiotiс origin to t>nеmadе tlp еntirеly ltеin world that Ьioсhеmiсal mасhinеry Ьranе strttсturеs'сomparaЬlе to thosе эsprеаd.This ls tlrus thе first timе that righthavе Ьееnprеsеrvеdin thе form of гliеr stagеswould hаvе lеft Ьс.hind only ot sttrvir.еdthе rar':rgеsof gеoсhеmiсаl : timе. Although traсеs of hydroсarЬon billion-r.еar-old sеdimеntaryroсks, thе s found tсl dаtе (Broсks et tl|. 1999), lation,аnd post-dеpositionalmеtamor. еаrliеr rесord of аЬiotiс organiс сhеm. .ithprimitivеlifе. lе еssеlltialfеattlrеsof gеn
ехtantforms of lifе Ьut also imply that thе sеts of gеnеs that еnсodе thе сomponеntsof thеsе сomplеx traits wеrе frozen a long timе ago (i.e., major сhangеsin thеm аrе vеry stгongly sеlесtеdagainst and arе lеthal). It is truе that no anсiеnt inсipiеnt Stagеsor еvolutionary intеrmеdiatеs of thеsе molесular struсturеshavе Ьееn dеtесtеd, Ьut thе ехistеnсе of gradеd intеrmеdiatеs сan bе dеduсеd'and thеrеforе thе supеrnatural origin advoсatеd Ьy Ьoth oldfashionеdand соntеmporary сrеаtionists is rеndеrеd unnесеssary. Foг instanсе,thе faсt thаt RNA molесulеs Ьy thеmsеlvеsarе сapаЬlе of pеrformingаll thе rеасtions involvеd in pеptidе_Ьondformаtiorr suggеsts'аs statеd еarliеr,that protеin biosynthеsis еvolvеd in an RNA world (Zhang and Сесh 1998|,that' is, that thе first гiЬosomе laсkеd protеins and wаs produсеd only by RNA' This possiЬility is supportеd Ьy сrystаllogгаphiс data that havе shown thatthе ribosomе'sсatalytiс sitе, wlrеrе pеptidе-bond formation takеs plaсе, is сomposеdof RNA (Ban еt al. 2000; Nissеn еt al. 2000). Сlurеsto thе gеnеtiс organizationof primitivе forms of translation arе also providеd Ьy paralogous gеnеs,whiсh arе sеquеnсеsthat divеrgе, not through spесiаtion, Ьut аftеr a dupliсationеvеnt.For instanсе' thе prеsеnсеin all known сеlls of pairs of homologous gеnеs that еnсodе two еlongation faсtоrs, whiсh аrе GTP (guanosinе triphosphatе)-dеpеndеnt еnzymеs that assist in protеin Ьiosynthеsis, providеs еvidеnсеof thе еxistеnсеof a moге primitivе, lеss rеgulatеd vеrsion of protеin synthеsisthat took plaсе with only onе еlongation faсtor. In faсt, thе еxpеrimеntalеvidеnсеof in vitro tгanslation systеms with modifiеd сationiс сonсеntrations lасking both еlongation faсtors and othеr protеin сomponеnts (Gavrilovaet aI' I976; Spirin 1986) strongly supports thе possiЬility of an oldеr prоtеin synthеsisapparatus Ьеforе thе еmеrgеnсеof еlongation faсtors. аnсеstral Bioinformatiс аnаlysis of sеquеnсеd сеllular gеnomеs from thе thrее major domainsсan Ье usеd to dеfinе thе sеt of thе most сonsеrvеd protеin.еnсoding sеquеnсes to сharaсtеrizе thе gеnе сomplеmеnt of thе LCA of еxtant lifе. Thе rеsultingsеt is dominatеd Ьy diffеrеnt putativе ATPasеs' and Ьy molесulеs in. volvеdin gеnеехprеssion and RNA nrеtaЬolisпr.Thе so-сallеd DЕAD gyrasеs' whiсh unwind RNA molесulеs and lеavе thеm rеady for dеgradation, arе аs сonsеrvеdаs many transсription and translation gеnеs.This suggеststhе еarly еvolutionof a сontrol rnесhanism for gеnе еxprеssion at thе RNA lеvеl, providingаdditional support to thе hypothеsis that RNA molесulеs playеd a morе prominеntrоlе during еarly сеllular еvolution. Сonsеrvеd sеquеnсеsгеlatеd to Ьiosynthеtiсpathwаys inсludе thosе еnсoding putativе phosphoriЬosyl py_ rophosphatеsynthasе and thiorеdoхin, whiсlr partiсipatе in nuсlеotidе mеtaЬolism. Although thе information сontainеd in thе availaЬlе dataЬasеs сorrеspondsonly to а minor portion of biologiсal divеrsity, thе sеquеnсеsreportеdhеrе arе likеly to Ье part сlf an еssеntiаl and highly сonsеrvеd pool of protеindomains сommon to all orgarrisms (Bесеrra et a|' 2007a). Thе high lеvеls of gеnеtiс rеdundanсy dеtесtеdin all sеquеnсеdЕ]еnomеs implyпot only thаt dupliсation has plаyеd a major rсllе in thе aссrеtion of thе сomplех gеnomеs foцnd in еХtant сеlls, Ьut also tlrat Ьеforе thе еarly dupliсationеvеnts rеvеalеd Ьy thе largе protеin familiеs, Ьесausе thе dupliсa' tion is usеd to Ьuild morе соmplехity, simplеr living systеms еxistеd that

71

72

Thе Оrigiп of Lifе laсkеd thе largе sеts of еnzvmеs and thе sсlplristiсatеdгеgшlаtoryaЬilitiеsof с о n r е m Г O r i ] г 1о 'г g а n i s m s .Т h е r ' a r i l t i t ' n ' . ' i t r l i t s с o l r ln l o l l t t l е х t an t s p е с i е s сan Ье еasily ехplainеd as thе outсоmе of divеrgеntproсеssesfrom аn anсеstrаl lifе form that ехistеd Ьеforе thе sеparation of thе thrее major Ьiologiсal domains, that is, thе last сommon anсеstor (LсA) or сеnanсеstor.No palеontologiсаl rеmnаnts likеly rеmain that Ье:rrtеstimony of its ехistеnсе'so thе sеarсh for::r fossil of thе сеnilrrсеstoris Ьound to provе fгuitlеss. Analvsis of an inсгеasirrglylargе nulrrlrегof сomplеtеlv sеquеnсеdсеllular gеnomеshas rеvеalеdmajrlr disсrеpanсiеsin thе topology of riЬosomal RNA (rRNA) trееs. Vеry oftеn thеsе diffеrеnсеs havе Ьееn intеrprеtеd as еvidеnсе of horizontal gеnе trаnsfеr (HGT) еvеnts Ьеtwееn diffеrеnt spесiеs,сasting douЬt uporr thе fеasiЬility of thе rесonstrttсtioгr and prсlpегurrсlеrstanding оf еaгly Ьiologiсаl histoгv (Doolittle 1999, 2000). Тhеге is сlеar еvidеrrсеtlrаt gеnomеs havе a mosaiс-likе naturе whоsе сomponеnts сotllе from a widе vаriеty of sourсеs (Oсhman еt al. 2000). Diffеrеnt advoсatеshavе dеsсriЬеda widе spесtrum of mix-and-matсh rесomЬination proсеssеs'ranging from thе latеral transfеr of a fеw gеnеs via сonjugarion, trаnsduсtiorr'оr transformаtion to се|l ftrsionеvеnts irrr,оlvingorganistrrsfrom diffеrеnt domains. Unil,еrsаl gеnе-basеdphylogеniеsultiгnatеlyrеaсh a singlе univеrsal еntitr,, Ьut thе Ьaсtеrial-likе LСA (Gogartеn еt al. 1989) that wе favor Was not alonе. It would havе Ьееn in thе сompany оf its siЬlings, a population of еntitiеs similar to it that ехistеd throughсlut thе samе pеriod. Thеy may havе not survivеd, Ьut somе сlf tlrеir gеnеsdid if rl-rеvЬесamе intеgrаtеdvia lаtеrаl transfеr il-ltotlrе l-СA gеnonlе.Thе сеnanсеstoris thtrsonе t>ftЬе last еvolutionary outсomеs of a sеriеsof anсеstralеvеnts' inсluding latеral gеnе transfеr, gеnе lossеs, and paгalogous dupliсatiсlns, that took plaсе Ьеforе thе sеparation of Bасtеria, Arсhaеa, аnd Еuсarya (I,azсano еt al. 1992; Glansdorff 2000; Сastrеsana 200 1; Dеlayе еt аl. 2004; Bесеrra еt аl. 2007a).

Сonсlusions and Pеrspесtivеs Although tl.rеrеhavе Ьееn сonsidеraЬlе advanсеs in thе undеrstаnding сlf сhеmiсal proсеssеsthat may havе tzrkеnplaсе bеf
thеiг mаintеnanсе аnd r syпthеsizеd Ьy pгеЬiotiс sumеs that thе raw mat tivе сhеmiсal systеms w геquirеd tо drivе thе сh. may hаvе bееn providе high.еnегgyсompolrrrds Thе Ьаsiс tеnet of thr maintеnanсе and rеpro. on prеЬiotiсally synthе hаs Ьееn no shortagе o diаl soup took plaсе.Br It is vеrу unlikеly that z

of organiс сompourlds and that thе сonsеquer еndogеnous synthеsеs synthеsis in dееp_sеav

oritеs, and intеrplrrтlеt thе rеlativе signifiсanс simply гесognizеs thе pounds' thе raw matеri As disсussеd hеrе, th bioсhеmiсalmonomеrs tions is wеll еstaЬlishе еffiсiеnt, Ьut thе widе r

сompounds сan Ье syn Ьuilding bloсks of lifе ; to thеm do not tаkе pl геaсtion сonditions bul Thе synthеsisof сhеп zymatiс proсеssеsundе thеy wеrе еithег еssеnt ronmеnt. Nonеthеlеss,l

stituеntsof living orgzr too striking to Ье foгtui portеd Ьy thе oссuгrеn Ьonасеous mеtеorltеs (

Ьесomеs plаusiЬlе, brpгimitivе еarth. Foг all a P P е а r st o u s т h a t t h е [ еstaЬlishеdеvеnts thзt Mainstrеam sсiеntif vеlopеd within thе fr

wеalth of еxpеrimеntа пarrаtivе thаt links m: issuеs.It is truе thаt th

Thе Оrigiп of Lifе :hе sophistiсzltеd rеgulаtory aЬilitiеs оf l n s o f t r a i r sс o t n m o n г o е х t a n t s p е с i с s е of divergеntproсеssеsfrom an anсrsеparationof thе tlrrееma jor biologiсаl сеstor ([-СA) or сеnanсеstoг.No pi.rlеLtЬеartеstimonvof its еxistеnсе,so thе s Ьorrndto pгovе fruitlеss. mЬеr of сorrrplеtеlysеqr.rеr.rсеd сe[lulzrr сiеs in thе topolсlgyof riЬosomal RNA nсеs havе Ьееn intеrprеtеdas еvidеnсе е n t s Ь е t w е е nd i t f е r е n ts p е с i с s .с а s t i n 8 tstrllсtiс'nand propеr unс{еrstandingсlf }9,2000). Thеrе is сlеar еvidеnсе thаt I o s ес o m p ( ) n е n tсs( ) m еf r t ' n l а w i d е v а . Diffеrеrrt аdvосatеs havе dеsсriЬеd а mЬinаtion proсеssеs'ranging from rhе jugation,transduсtion,or transformaanisms from diftЪrеntdomаins. tirnatеlyrеaсlra singlе ur-rivеrsal еntitу, r еt al. 1989) that wе fаr,or wаs not ' a n y o f i t s s i Ь l i n g s ,а p o p u l a t i o n o f е n hout thе samе pеriod. Thе,v nray havе tid ii thеy Ьесatrrеintеgrаtеdviа latеral nаnсеstoris thus onе
rdvаI-tсеs irr гhе urrdеrsrirrrdir.rg of сhеrn: ЬеtЪrеthе еmеrgеnсеof thе first livirrg " l d е di n m y s t е r ) ' L. i k е v е g е t e г i < linn а al phvlogеnеtiсtгееsarе suЬшеrgеd in t, :rndhow tlrе transition frоm thе nor-rknown. Givеn thе hugе gap that ехists ry transition Ьеtu,ееnthе prеЬiotiс synhе lаst сOmmon аnсеst()rof all ехtant еmpt to сomplеtеlydеsсriЬеthе oгigin ystеmsfrom molесular phylogеniеs. сs, Ьioсhеmistry.сеll Ьiolсlg,v,and thе nismshas сhirllеngеdmarly сlгiginalasThе viеw advoсatеd hеrе assumеs that owеd with minimal synthеtiс аЬilitiеs,

theirmаintеnanсе and rеpliсation dеpеndеdprimагily on organiс сoп-tpounds synthеsizеdЬy prеЬiotiс proсеssеs. An updatеd hеtеrotrophiс hypothеsis assumеsthat thе raw matеrial for аssеmЬling thе first sеlf-maintaining, rеpliсadvе сhеmiсa]svstеп1s\t,as thе оutсomе of аЬiсltiс syrrthеsis,rvhilе thе еnеrg), геquirеdto drivе thе сhеmiсаl rеасtions involvеd in growth irnd rеprodr.rсtion may havе Ьееn prсlvidеd Ь,v сyanamidе, thioеstеrs' glyсinе nitrilе, or othеr high-еnеrgy сomporrnds(dе Dtrvе 199S:Lazсano and Millеr 7996). Thе Ьasiсtеnet of thе lrеtеrotroplriсthеory of thе origirr of lifе is that сhе maintеnаnсе anсl rеproduсtion of thе first living еntitiеs dеpеndеd primarily on prеbiotiсallysvnthеsizеdorganiс molесulеs. As summarizеd hеrе, thеrе hаs Ьееnno shortаgеof disсussitlnaЬottt how tЬе formаtion of thе primordial soup took plасе. But lr:rvеtoo mal1y сooks spoilеd thе sсlup?Not rеally. It is vеry unlikеli,that any singlе mесhanism саn aссount for thе widе rangе of organiссompounds thаr rnay hаvе aссumulatеd on thе primitivе еa]rth' аnd that thе сitnsеquеntprеЬiotiс sollp Was formеd Ьy сorrtгiЬutionsfrсlm еndogеnoussynthеsеsin a rеduсing аtmosphеrе, mеtal sulphidе-mеdiatеd synthеsisin dееp-sеavеnts' and еХogеnous sourсеs suсh as сomеts' lтlеtеoritеs,аnd intегplirnеtarvdust. This есlесtiс viеw dfnrt>stof thеsе Ьioсhеnriсаl сompounds in thе сarmеtеoritеsof 4..5Ьillion yе:lrsago (Еlrrеnfrеundеt al. 2001). So it Ьonaсеous bесomеspiausiЬlе, Ьut ntlt provеl1' that similar synthеsis took plaсе on thе primitivееarth.}-orall thе unсеrtaintiеssurrоunding thе еmеrgеnсеof lifе' it apреаrsto us th21tthе forrrrаti
/)

74

Thе Оrigiп of Lifе lutionary transitiorr Ьеtwееn thе prеЬiotiс synthеsis of Ьioсhеmiсal сompounds and thе last сommon anсеstorof аll ехtirntliving Ьеings' Ьut attеmpts to rеduсе it havе аllowеd а morе prесisе dеsсription of thе Ьеginning of lifе, Nowadays а сеntral issuе in origin-оf-litЪrеsеarсh is to undеrstаnd thе abiotiс synthеsisof an аnсestrаlgеnеtiсpolymеr еndowеd with сatalytiс aсtivity and its furthеr еvolution to an RNA world and ultimatеly to thе DNA/RNA/protеin world сharaсtеristiс of all lifе on еarth. !Ие faсе major unsolvеd proЬlеms, but thеy aге not сompletеly shroudеd in mystеry, unsolvaЬlе, or unknowaЬlе. B|вLloGRAPнY 'W.. Allwood,A. с., I. Burсh,M. R. Waltеr,аnd B. S. KаmЬеr.2007. з.4З billion.Wеstеrn yеar.oldstrom:rt
Burkhaгdt' F., and S. Smi СЬаrlas Dаrшiп, 182 Univегsitl' Prеss. Bvеrlv' с. R.' Г). R. Lorr, l:r}'егfгоnl thе PilЬаr C a l r , i n ,M . l 9 6 9 . С h е m i , LiL,iпg Sуstеms oп tb C а s t r е s a n a ,J . 2 0 0 1 . С o п l Biсlpbуsiса Асtа 150 Сhеn, I' A. 2006. Thе еп. 15.58-15.t9. СhyЬа, С.. and С. Sagan imрасt.shoсk synthе Iiie , Nаturе З55: 12. Сlе:rvеs,I_{..l.' J. Н. Сhal rеаssеssmеntof prеЬ Оrigiпs of l-ifе апd 1 Сoopеr, G., N. Kimmiсh. CirrЬonасеous mеtес thе еarly еarth. Nс/'r Dаhnl' R. 2005. Friеdriс B i с l l t l g l 2, 7 8 : 2 7 4 _ 2 t Dilrwin, F. lE8-. Тhс Li1 Аutobi
D o u d n a , J . A . , a r r dТ . R . Nаturе 418 222_22 Еghсl|m,М.' o. Buсhard (PNA): oligonuсlеo thc Аmеriсап Сhеm P., D. P' G Еhrеlrfгеr'rr-rd, Е х t г . r t е г г е s t r li nl m i СI typе сitrЬon.lсес Sсiепcеs USА 98: 2 ЕiсhЬеrg' .|.,Е. Shеrwoo synthеsеsundеr pla Е u t ' l t t l i t t lп0 : 2 2 | _ Еsсhеnrnosеr, ^. 1999. ( 2t 18-2\24. 2004. Thе TNA origilts сlf 1'ife апd F е г г i s ,J . P . 2 0 0 f . М o n t

Тhе ()rigiп сl| Lifе

otiс synthеsisof Ьioсhеmiсal сomall ехtantliving Ьеings,Ьut attеmpts : dеsсription of thе Ьеginning of lifе. геsеarсhis to undеrstand thе аЬiotiс lndowеdwith сatаlytiс aсtiviгy and its ultimatеly to thе DNA/RNA/protеin /е faсе ma|or unsolvеd prоЬlеms, Ьut еry' unsolvaЬlе,or unknowablе.

n d B ' S . К a m Ь е г2. 0 0 7 .з . 4 3 Ь i l l i o n Austrаlia: Есosystеm-sсalе insightsto h 158 198-227. statusrерort.Еаrth PIапеtаrуSсiencе 4. Impaсtmеltingof frozеnoсеanson in of lifе. Prсlt:ееdiпgs of thе Nаtioпаl ;0. o, H.J. Сlеavеs,R. М. Hazеn,аnd rr thеoriginof lifе on eartЬ.Sсirпсе :vеаlеdnеw waysto studythе оrigins of firstЬiоmоlесu|es. Sсiепсe296: Иillеr ехpеrimеnt. Sсiепсе3ОО:74 5-7 46. Thе stаЬilityof aminoасidsat res.Оrigiпsof Life апd Еuolutioп of d T' Stеitz.2000.Thе сomplеtеatomiс r 2.4A rеsolution. Sсiеltсе289: 905-920. .Гrепds сtingan RNA world. iп Сеll с>.2007a. Vеryеаrlystаgеsof Ьiologiсаl сommonanсеStor of thе thrееmajor сеll iиtioп апd Sуstemаtiсs 38 361-З79. rge|'2007Ь.Protеindisulfidе lrпrophily:Wаsthе last сommon of МolесulаrЕuсllцtioп65: 296*3ОЗ. H. Konig,and K. o. Stеttеr.1984. sпrokеr', сonditions. . i a Io r g a n i с o m p o u n disn m е t е o г i t е s . (. Klеppе,М. vаn Krаnеndonk, F. J. . 2002.Quеsrioningthе еvidеnсеfоr ). ry: A non-hypеrthеrmophiliс anсеstor ].Summons. 1999.Arсhеanmolесulаr сiеtlсе 285 1033-10з6.

Burkhardt,F', аnd S. Smith, ес]s.|994 . А Саlспdаr of tbc Сtlrrеsprlltdепсеtlf СhаrlеsDаru'iп, 1821-1 I]82, \Yith Suрplепtепt. Сzttл|lridgе:()апrЬridgе UnivеrsitуPrеss. .Woodеll, Bvеrlv,G. R., D. R. l-сlwе,J. L. and Х. Хiе. 2002. An Arсhсan irrrpасt laуегfrorrrthе РilЬага аnd K;rаpvaаIсr.аtolls.Sсiепсс 297: |32.5_1З27. Сalvin' М. 1969. Сhеmiсаl Еun Prеss. 2001. Сornparativt.gеllollliсs and lrioеnеrgеtiсs.IJirlt-llimiсаеt Саstrеsаna,J' Biop|lуsiсаАсrа 1.506:|47_162. Сhеn,I. A. 2006. Thе еmеrgспсеof сеlls с1uringtl.rеtlrigin of |ifе.Sсiепсе 374 1558-1-5-59. Сhvba,С., апd С. Sаgаn. l992. ЕrrdоgеnOusproduсtioll. ехOgеl)tlllsdеlivеrv rrrrd impaсьshoсksynthеsisof organiс пlolесulеs:An ilrvеntOrVfсlг thе origins сlf |ife.Nаtt,trе 355: 12.5_1З2. С i е а v е sH, . . l . ' J . Н . С h а l п r с r s .А . [ , a z с а n t lS' . L . N , I i l l е ra, r l d J . L . t ] а d а . 2 0 0 8 .А rеassеssmеnt of prеЬitltiсorg:rrriсsynthеsisin rrеutrаlp1anеtirтvetmсlsplrсrеs. Оrigiпsof Lifе апd Еurllttti,опоf thе Birlsphсrе З8 l0.5_11.5. Сooper,C., N. Kimmiсh, W. Bеlislе'.].Sаrilrаr.rlr' K. BreЬlrarrr,aIlсl L. GаrrеI.2001. СarЬonaсеousпrеtеoritеsаs a sourсе of sugаr-rеlirtесl сlrgаrriсссlmpouridsfor thе еаrly ea|t|1. Ndturе 4l4: 879_88з. Dahm,R. 200.5.FriесlriсhМiеsсhсr аnrl tlrе disсovеrv оf Dп.A. Dcrсlсl1llltспtll Blolo3r'2-8:2-4-28Ь. Darwln,F. ]887. Тhr Lifе апd Lеttеrs rlf Сhаrlеs l)апuiп, ]псlttdiпs аlt Аut o bi ogr а1lh i са l (',hаp tеr, Lorrdoll : M urrir1.' Dеamеr,D. W., arrсlR. M. l)irshlсy.l9tt9. Arnрlriphiliс сtlnlpоurrсlsсlf tlrе Мurсhison сarЬonaсеousсhondritе: SurftrсерropеItiеsanс1mспrЬr:rtrе formation.()rigiпs of Lifс апd Еutllиtion rl|-thеBirlsрllеrе 19 21_З8. dе Duvе,с. l995. \/itаlDLrst:I-it'.е аs а Соsmiс Impеrаtit'c.Nец, York: Birsiс Books. -. 200з. A rеsеаrсhproрosаl oп thе ()riginof |ifс. Оrigills o| I-ifc апd Luolullo1l

О | I п е 1 5 l | ) s D l J с , 1 '. i i : ) . ) y _ ) , / Z t .

DеIаvе,L., A. Bесerrir,апd A. Lаzсаllсl.2004. Тlrе rlаturеоf гhс lаst сопmolt anсеstor.In L. RiЬas dе Pсluplirnаr, еd.,Thе Gепеtiс (,,odеапd tbе origiп of Lifе, 34_47. Gеrrгgеt. 977. Сr.аrlаmiсlс rrlеdiateсl svnthеsеs undеr plаusiЬIсрriIrritil,сеirrth с()llditiotts. '|rlttrпаltlf Мolесttlаr Еuolutioп |0:221-230' Е s с h е n m o s еАr ,' .1 9 9 9 .С h е m i с l r lе t i r l l t l g r ' o n f r-rсIеiсасidstгttсturе.Sсiепсе?81 2118-2124. --. 2004. Thс TNA-family of nuсJеiсасid svstеtns:Рlopегtiеs апс1glrosресts' Оriginsof Lifе аlld Еurlltttioпof thе Bitlsphcrе З4:2-a7-З06. Ееrris,J. P.2002. N{оnгrnorill
7.t

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Thе Оrigiп of Liiе LaЬoratory dеmonstrаtion of potеntial stеps in thе origin of thе RNA world. Оrigiпs of Liiе апd Еuсllиtiсlпсlf thе BiospЬеrе З2:311-332. Fеrris, J. P., P. D. Jоshi, Е. I{. Еdеlsоп, аnd.|' (}. Lаrvlеss. l978. HСN: A plausiЬlе souгсе оf purinеs' рyrirnidinеs, аnd aminо aсids on thе primirivе ..afih,.lourпаl оf Мoleсulаr Еuolutioп 1'1':29З.311, Fortеrге' P.2002. A hot storv from с
2006. сr-Hydroхyl аnс1с origin-of-lifе ссlnditiоns'Sсr Islаs,S., A. N4. Vеlаsссl'A. Bесег and tЬе origin of lifе. In Сhr' апd lJillсhеlпistrу of F,хtrеlп J o v . с , G . Г . .2 ( ) 0 ] . Т h с r r r г i q u i t Kаnavarioti, А.' P. A. Mсlnnаrt] faсil itаtе nOnеnzvtтlatlсlltlс K : r s t i n g J, . F . l 9 9 З а . Е : r r I yе v t l l r GrееnЬегg, С. Х. ]Vlеrlсloz Lifе's Оrigiпs, 119_176' Dt PuЬlishеrs. 1 9 9 3 Ь . Е а r t l r ' sе a r l v а t п K е I l е y ,D . s ' . . ] . A . K a г s r l r l ,D . K Buttегfiеld' М. D. l,illеy, Е. Rivizzigntl' and thе AT3-60 vеnt fiеlс] llеar thе Мiсl-Atlа KolЬ, V. M.,.1. P. Dworkin, and wоrld: Tlrе prеЬiсltiсsvnthе Е ul llu t k l tt .]t]: .549_5.57. Kozlсlv, I. A., L. Е. orgеl, and P trаnsmittеd Ьy an aсhiral pt llttcrпаtitlllаl Еditirlп З9 4. Кltmаr, R' lr., and r\l. Yаrus.20 B io с h еmi strl' 40 : 69 9 8-7 0( l-arr:rldе,R.' N,I.P. RoЬегtson,а r i Ь o s е ; r l l dl l t h е г s t t ц l r s - t ; l thе Nаtitlпаl Асаtlеtпу rlf St Lаzсano, ^. 1997. Тhе tеmpo aг S. Bowvеr' lrnd D. \Vсrthinl thе Sеаrсh for Lifс iп thс Ul Lаzсano, A., G. Е. Fсlх, аnd J. С сlf еаrly Aгсhеtrn. еr,oluti
Thе Оrigiп of Lifе ps in thе origin сlf thе RNA worlсl. ,hеrе32:311-З32. i. Lаwlеss.t978. НСN: А plausiЬlе aсids on thе рrimitivе eartЬ.lОurпаl е gеnomiсs:Rеvеrsеgyrasе is thе епds iп Gепеtiсs 18 2.36_2З7. э, аnd М. Duguеt. 2000. Rеvеrsе гensfеo r f t t r h е r m . l а d a p t а t i otnr а i r iсs 16 152_154. l, A. G. Сhristy, Nl. J. van [-assеmЬlеd siliсa.сarЬonаrе lssils.Sсle,сs 302: 1194-7197. and S. A. Bеnnеr.2,008.Irrfеrringthе :hеЬаsisof rеsurrесtеdpr()tеrns. .liansky,N. M. Rutkеvitсh, and A. S. J faсtor-depеndеnтs1.stеmsof hiа сoli riЬosomеs.Jourпаl of d . N а t и r еЗ | 9 : 6 1 8 . IапеtСhапgе 1: 35-55. nсеstor'tЬе univеrsаl lifе-trееаnd llаr Мiсrolliоlog1'38: |77-|85. i. J. Bowman' B. J. Bowman' М. F. , J. Konishi, K. Dепda, and ar l{+-AТPаsе:Impliсations for thе :ionаl Аcаdamу of Sciепсеs USА 86: ,artеn.1995. Thе еffесtsof hеavy :ion of lifе-а nеw look аt thе иtioп of thе Biosphеrе 25:78_83. laсtеriа likе it hot. Nаturе 451 m of mеmЬranе topology. Nаturе

024.

stak.200З. Ехpеrimеntаl m.ldеls
2006. с-Hyсlгсlхyl alrd O(-аminoасids unс]егp
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Tbe Оrigiп of Lfe .l 955. Produсtiсln of somе
S l е е p ,N . Н . , K . J . Z a h л r c есosystепls by lаrgе ar S o w е r l ' y .s . . I . 'С . M . М о r аdsогptior.rof adеninе Spirin,A. s. l986. Rlbosс Bеn jamin/Сummings' Springstееn, G., and (]. F. rillоsе |гсlm lr prеlliог 9578-95 8з. Stoks, P. G., аnd A' W. Sс 282 709-710. 1981. Nitrсlgеn-h mесhanisms of foгmа l982. Bаsiсnitrog G есlсhimiса еt Ссlslпt S t r е с k е r ,A . 1 8 5 0 . U Ь е r d i Glyсoсoll homсllсlgе Tеhеi, N4., B. Franzеtti,M 2002. Thе sеarсh foi maсromсllесulеs.Ехlr Tian, F., o. Toсln, A. Pаvl аtmosphеге. SсiепссЗ Тiсе, М. M., аr.rdD. R. l-r Мyr-old oсеan. Na/и . Uеno, Y., K. Yilmасlа,N. from fluid irrсlusions] Nаtltrе 440:5l6-.5 l9 van Zuilеn, N4. A.' A. Lеp thе еаrliеst trасеsof li W;iсhtеrsh:iusеr,G. 1988. mеtirЬolism. Мiсrоbir \й7аng,Х. s. l998. StаЬili сonditions. PhD thеs С i r I i f t l r n i . lrt 5 : l n D i е W е t h е г i | |G, . W . l 9 9 0 . F о Sсieпсе 1t]:20.5-2.56 .!7hitе, R. H. 1984' Нydrс impliсation for lifе аt \}/ildе, S. A.' J. \W.Vаllеy, dеtritаl zirсons foг th Gyr ago. Nаturе 409 Yuasа, S., D. Flory, B. Bas сlthеr hеtеroсyсliс соr Мllleailаr Еuсllutiolt ZaЬn],е,K., N. Arndt, С. t 2007. Еmсrgеt"tсеof с ZЬang, B., and T. R. Сес| riЬсlzymеs. Nаturе 39 с ZllЬaу, G. 1998. Str.rdies Lifе апd Еuсllutiсlп ,,

Thе Оrigiп of Life npоundsundеr роssiЬlеprimitivе СhеmiсаlSoсiеtу 77:2З51_2361 . amino aсids Ьy еlесtriсdisсhargеs. 89. ltiс сhеmistry. N аtttrс StruсturаI hot springsаnсl tlrе origin of litе. n of lifе-diс] it oссur аt high t t i о п4 1 ' : 6 8 9 _ 6 9 2 . o m p o u n ds y n t h е \ i \u n t h е p r i m i г i v с ). Pеptidеnuсlеiс асids rathеr thаn :сuIе.Proсеесliпgstf thе Nаtklпаl LdT. Stеitz.2000..Гhеstruсturаl Ьasеs lеsis. Sсiепсе 2.89: 92О_9З0. nan.2000. Lirtеralgеnе transfеr and , 405 299_3О4. s: Thеorеtiсаlintroduсtion. Оrigins оf 27-234. lnium сyanidе.Biосhеmiсаl аnd 407412. oсhеmiсaiсompounds rln thе pr"rrinеs undеr possiЬlеprimitivе еarth nidе. Аrсhit,еs of Bioсbaпtistrl' аnd d S. A. Bеnnеr.2004. Borаtе minеrаls S c i е n c е2 9 3 : 1 0 5 6 _ 1 0 5 8 . --.]_786. ifе. Pеptidеs20: tlrе iron-sulfurworlсl аnd its rеlеvanсе г i с s y n t h е s i i' r tl t г r t t o s p h е rсеos n г . r i r t i r l g шl of Мolесulаr Еutiutklп !9: . L,аnd S. x,IoorЬаth'2002. Tungstеn h о s е ds е d i m е n t fso r е а r | vm е г е r l r i t е 03-40.5. R . К г i ч h n . r m r r г г' h. rl r r dA . nuсlеiсaсid strllсгurе:Тhе сx. stem.Sсiепсе290: |347_1351, rrсhaеanApех сhеrt:Nеw еvidеnсе -646. sotopiс еvidеr-rсе foг miсroЬiа1 эr'.l.Nаtur е 410: 7 7-8 |. l thе oгigin of rlrgапiсссlпrpoundsin :l Еuolutioп rli tllе Birlspbеrе 2О: с s y n t h е \ i ds u r i r r gf l u i d m i x i n g i r l ,siсаIRеsеаrсh10З: 28.513_28528. эхidе сyсling and irnpliсationsfсlг hуsiсаl Rеscаrсh 106: 1з7з-1з99.

S l е е pN , . H . ' K . J . Z а h п l е , J . F . .K а s r i r r g sа, r r d H . J . M t l r o r v i t z . 1 9 8 9 . A n n i h i l a t i с l пс l f есosystеmsbу lагgе ilstеroid iIтpасts On thе еаIly еarth. Nаturе З42:139_|42.. SowеrЬy,S. J.' с. N,l.Mrirth, and N. G. Holпr.200l. Еffесt сlf tеmpеratuгеOn thе аdsorptionof асlеrrinе.Аstrobirllogl 1: 481487. Spirin,A. S. ]986. Rillоstllпе Struсtttraаltd Pкltеiп tsirlsуnr|2с'i''Меnlo Pаrk, СA: Bеnjamin/Сum nl ings. G.' arrсlG. F. Joyсе. 200,1.Sеlесtivеdеrir'irtiz:rtiсln аnd sеquеstrlltiоnOf Springstееn, riЬosе frсlпl a prеЬitltiс mtх. Jсlurп,tl
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Narrative

Paleontologyand the History of Life Michael Benton And out of the ground the Lord God formed every beast of the field, and every fowl of the air; and brought them unto Adam to seewhat he would call them: and whatsoeverAdam calledeveryliving creature,that was the name thereof. G e n e s i s2 : 1 9

Peoplehave always been astoundedby the diversity of life, although perhaps in different ways. In prescientifictimes farmers saw how their crops and livestock were merely part of a much larger richnessof life, ar-rdpeople have alwrrys striven to understandthe complexity and arrangementof living things. From Aristotle to Linnaeus,scienristsatremptedto catalog life and to understand where it had come from. During the eighteenth century it becameclear to all savantsthar the earth had beenpopulirtedformerly by strangeand marvelous creaturesthat had since becomeertinct. Bv 1820 some rough picture of the successionof floras and faunas through geological time was beginning to emerge.Charles Darwirr, during the voyage of HMS Beagle in the early 1830s, becameincreasinglyconvincedthat life was more diversethan he had imagined-every island he visited sported a new crop of plants and animals. He saw the lateral (geographic)and vertical (historic) links between species and realizedby 1837 that speciesrvereall linked by a great tree.The tree concept made it clear why speciesthat in his time were geographicallyclose should also be genealogicallyclose. Further, the tree conc€pt made it clear why the fossil mammals he found in Argentina should be similar to the living mammals of the region. This essayaddressesfour concepts:what we know about the sequenceof the history of life, how life has diversified through time, how speciation occurs, and how good (or bad) the fossil record is as a sourceof data on the history of life. These were all issuesthat concernedDarwin (1859), and they concern us still today.

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There are many ways to re( nren)'fvpical examples,Bent o f l 0 s t a g e sf r o n r t h e o r i g i n

l.The origin of life.The tt fossil recorcl,some 3.6c e l l sw e r e p r o b a b l y l i k e but they lived in the irbs 2. Eukarycttesttnd the oriS nucleus,are reporteclfrr ar.rdhencepresum:rblya o f s e x u a lr e p r o d u c t i o n possibly no eukar,votes, mrrterialancl reconrbin 3. Multicellularity. The hr billion-950 nrillionyea m o l e c u l a re v i d e n c et h a t s o m e 1 . 2 b i l l i o n y e a r si 1 d i r e r s i f yt h e f u n c t i o r rrs 4 . S k c l e t o n sN. l r n y l n r m a skeletonsabout 545 rni Phanerozclic,during thc are known from many I d i v e r s i t yo f p l r v l a r c p r e skeletonsu,ereaccluire skeletonsclearly ofierec g r o u p s t o e n t e rn e w l i f c 5. Pretlation Perhapslink protective outer shells,r predato rs, tnacrosco1't ic strategiesto feed on the prey becamea st:rndar 6. Bictlogical reefs. Reeis l been made from a broa polychaeteu,orms in th l.ate Cambrian and alg tabulate corals in the O groups of algae,sponge through time, but reefs scleractinian c o r a l s .R e rnrrjor physical geograp habitats for life. 7 . Terrestrialization. The t huge arra,vclf new life z

Pаlеoпtolrэg1' апd thе Нistсlrу of Lifе

Naгrativе

d thе History

rnrеd еvеry Ьеast of thе fiеld, and unto Adam to sее whаt hе would еvегy living сrеaturе' tЬat wаs thе

G е n е s i 2s : 1 9

е divегsityof lifе, although pеrhaps гmеtssаW how thеir сrops and livеriсhnеssof lifе, and pеoplе hаvе aly and arrangеmеntоf living things. lmptеd to сatalog lifе and to undеrе еightееnthсеntury it Ьесamесlеar :lаtеd formеrly Ьу strаngеand marкtinсt.By 1820 sonrе rough piсturе эugh gеologiсal tirnе was Ьеginning ,оyagе of F{МS Beаgle in thе еarly rt lifе was morе divеrsе than hе had l a nеw сrop of plants and animals. i с а l ( h i s t t l г i сl)i n k s Ь е t w е е ns р е с i е s linkеd Ьy a greattrеe. Thе trее сonris timе wеrе gеographiсally сlosе hеr, thе trее сonсеpt madе it сlеar ntina should Ье similirr to thе livins tаt wе know аЬout thе sеquеnсеof l through timе' how spесiation oсэrd is as a sourсеof data on thе hislnсernеd Darwin (1859), and thеy

.Гhеrе аrе many ways tO rес()untthе stсrrytlf thе history of lifе. As
8,l

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Pаlеoпtrllсlgуапd thе Historу of Lifе PrесamЬrian suссеssions,and soils imply lifе on lalrd. Buгrowing animаls arе known from ()rdoviсiаn soils, whilе mаny smаll vasсular plants and artlrropods arе known from thе Siluriаn. Land plants Ьесamе larger z.rndmorе divеrsе in thе Dеvoniаn, аnd tlrе divегsitу of land-dwеlling,animals ехpandеd to inсludе Worms' mсlllusks,many morе arthropсldgroups, and vеrtеЬratеs. 8. Тrеes аnd fсlrеsts.Just as rееfs in thе sеzrarе gеographiсally suЬstantial Ьiologiсal struсturеs,so too arе forеsts.Thе first trееs il-t thе Devoniаn Wеrе largеly isсllatеd,btlt massivе forеstsdеvеlopеd in thе СarЬonifеrous, with trееs up to 20 m tall. Not only did variсlus land-plant groups divеrsify аs trееs' Ьut othеr plants and animals that ехploitеd thе nеw habit:rtsсrеatеd Ьу thе trееs аlsо divеrsifiеd. 9. Flight. A ftlrthеr ехpansion of есosp;rсеwas markеd Ьy thе origin of flight. Insесtsarosе in thе Еarly Dеvonian, Ьut thе first truе flyеrs wеrе CаrЬonifеrous in agе. Inseсtsdominatеd thе skiеs from thеn on. Thе first flying (gliding) vеrteЬratеsarosе in thе Pеrmiiln and Triassiс, whilе powеrеd flight in vеrtеЬratеsarosе at lеast thrее timеs' in ptеrosaursin thе Latе Triassiс, in Ьirds in thе Latе Jurirssiс, аnd in Ьats in thе Tеrtiary. Thе origin of соnsсioust-tеss 10. Ссlnsciсlusnеss. in humаrrsis muсh dеЬatеd.Is this a fеatr'rrеoi Homсl sсtpiепsalonе, and henсе pгеsеnt only in thе past 200,000 vеars or so, or did еarliеr spесiеsof Hсlmo, or еvеn pгесursor gеnеra suсh as АustrаlopithеcИs afld Ardipithесus' possеssсonsсiousnеssas mltсh as 2 tn,сonsсitlusnеss)and major ехpаIlsitrns in haЬitats oссupiеd Ьy lifе (rееfs,tеrrеstrialization,trееs, flight). All 10 arе . doсumеntеd to a gгеаtеrоr lеssеrехtеnt in thе fossil rесord. In a morе Ьiologiсаlly oriеntеd prеsеntation' .|ohn Мaynard Smith and Ебrs Szathmarу (995) idеntifiеd еight major stеps from thе с>riginof lifе to human soсietiеswith languagе: 7. Rеpliсаtiпg molесules. Thе first oЬjесts with thе propеrtiеs of multipliсation, vаriation, аnd hеrеditywеrе probaЬly rеpliсating Inolесulеs,siпrilаr to RNA Ьut pеrhaps simplеr and сapaЬlе of геpliсation Ьut not informationаl Ьесatrsеthеy did nOt spесify othеr struсturеs.A populaг viеw is thаt RNA сamе Ьеforе DNA Ьесausеit саn aсt Ьoth as il gеnе and an еnzymе' viеrvsеnсapsulatеdin thе tеrm RNА шorld' If evrllutiorrwerе to proсееd fuгthег,it rvas nесеssary that diffеrеntkinds of rеpliсatingmolесuIеshould сoopеratе,еaсh pгoduсing еffесts that hеlpеd thе rеpliсаtion of сlthеrs.For this to hаppеn, populations of molесulеshad t
2. lndеpeпdепt rеpliсс or gепеs' аrе linkеd сlrromosomе pеr се wlrеn onе gеnе is rе Pгеvеnts сolllPеtitio с()()pеratiOnon thеI 3. RNА аs gе|1еапd ei laЬor bеtwееn two ( that storеаnd trans rеaсtions and form musсlе, tеrrdоn,hai Ьotlr funсtions. Thе :rnd pгotеin rеquirеr sеquеnсеdеtеrminе 4. Еukаrусltеs апd org h:rvеa singlе сirсtllа с у a n с l Ь a с t е г i a( Ь l u е сontains rod-shapес struсturеs сallеd orд Тlrе еukaryoсеs inсlr сеllеd AmoеЬir and 5. Saхuаl rеproLluсtior i n d i v i d u a l sa r i s е a s . two. In nrost ешkarу сеll division may Ье rvhiсh а nеw individ gаmеtеs' produсеd l 6. D i ffеreпt iаtе d сe lls. сеlls сlf onlу OI1еor pla alтlong anirrrаrls, kinds of сеlls,suсh . Еасh individuаl,thе inforrтation (trvo in pr
l,аlеoпttllogу,аndthе Histor1,of LiIa ; imply lifе on land. Burrowing ln soils,rvhilе mani, small vаsсulаr from thе Silurian. Lаnd plarrts thе Dеvoniаn, and thе divеrsity of l inсludеwoгms' rr-rollusks, mаny Ьratеs. hе sеа аrе gеographiсally c too arе forсsts.Tlrе first trеes in l, Ьut massivеforеstsdеvеlopеd in o 20 m tаll' Not сlnly did vaгious s' Ьut othеr plants and animals :atеdЬу thе trееsalso divеrsifiеd. spaсеWas mаrkеd Ьy thе origin of ]vonian, Ьut thе first truе flyеrs ;dorninatеdthе skiеs from thеn on. s aгosеin thе Pеrnriаn and ]rtеЬratеsarosе at least thrее iassiс,in Ьirds in thе Latе Jur;rssiс, сiousnеssin humans is muсh sаpiепsаlonе, аnd lrеnсеprеsеnt ;o' оr did еаrliеr spесiеsof Нсlmo, \ustrаlop itЬесus aлd Аrdip ith eсиs, 2 ttl 4 million yеars ago? сrеatеthings and to modify thеir rе pгofound impaсt Ьumans irге or Ьiologiсal innovаtions (lifе, sех, r s с i o u s n е s sа)n d r n , jro r е х p i r n s i o n s rialization,trееs' flight). All 10 аrе n thе fossil гесord. ltаtion' John Mayrrard Smith and ajor stеpsfrom thе origin of lifе to jесtswith thе propеrtiеs of J i t у w е r е p r о Ь а Ь l yr е p l i с a r i n g raps simplеrand саpaЬlе of |есatlsеthеy did not spесify othеr lNA саmе ЬеforеDNA Ьесausеit mе' viеws еnсapsuiаtеdin thе tеrm roсееd furthеr, it was nесеssary rolесuiе should ссl
2. Iпdеpeпdепtrepliсаttlrs.In ехisting organisms,rеpliсating molесulеs, or gепеs' arе lirrkеd togеthеr с'nd tO еnd to forлl сhromoso|7'еs (а singlе сhromosomеpеr сеll in пrсlstsimplе оrganisnrs).This has thе еffесt thаt whеn onе gеnе is rеpliсatеd,аll arе. This сoordinatеd геpliсation prеvеntsсonrpеtiti()tlbеtwееngеnеs within a сompаrtmеnt and forсеs сoopеrationсln thеm, sinсе if сlnе fails, thеy all fail. з.RNА оs gеnе апd eпzl,mе.in modеrn organisnrsthеrе is a division of iаЬor Ьеtwееntwo сlassеsof mоlесulе..писleiс', ссids (DNA and RNA) that storе and transmit information aпd protеiпs thаt сatalyzе сhеmiсal rеaсtionsanсl form rnuсh rlf tlrе struсturе of thе Ьody (for ехan-r;llе, musсlе,tеndсln,hair). Pеrhаps originirlly RNА molесr.rlеs pеrfсlrmеd Ьoth funсtions. Thе tгansition frсlm an RNA rvсlrld to a wсlrld of DNA and prrlrеinrеquirеd thе еvсllutionof thе gеnеtiсссldе,r,vhегеЬyЬasе sеqtlеnсd е е r е г m i n е sp r о t е i ns t г u с t u r с . 4. Еuktlrусltеsапd orgаllеllеs.Prсlkаrуr;tсslaсk а nuсlеus аnd usualry hаvе а singlе сirсulаr сhrtrпrosomе.Тhеy irrсlLrdеthе Ьaсtеriа аnd сyarroЬaсtеria(Ьluе-grееnalgaе).Еttkаrуotеs havе а nuсlеus that сontainsrod.shаpеd сlrromosсlmеsanс]usuallу othеr iгltraсеllulаr г strttсtllrеsсa||еdсlrgtlпe//es' inсludirrgmitoсhсlndria .rгrdсhlоroplasts. Thе еuk:rryotеsinсludе all othеr сеlluIar organisnrs,fronr thе singlесеllеdAmt>еЬit,.lnd Сhlаm1,dtlпrlпаsttp to hul.nans' 5. Sехuаl rеprodисtiot;.In prokaryotеs аnd in somе еukагyotеs'lrеw individuals arisе as аsех|tаlсloпеs Ьy thе divisiсln of a singlе сеll into trvсl.Iп most еЦkar\'otеs,in с()iltrastithis prсlсеssof multipliсаti
8l

Раlеoпtoklgу апd thе Historу of Life 8. Primаtе sociеtiеs, bumап soсiеtiеs, апd thе origiп of lапguаge. The dесisivе stеp in thе trаnsition from apе to human soсiеty was proЬаЬly thе origin tlf languagе.In many wаys human languagе is likе thе gеnеtiс сodе; information is storеd and transmittеd,with modifiсatron, down thе gеnеrations.Сommuniсation holds soсiеtiеstosеthеr and allows hunrans to еsсapееvolution. Мaynard Smith and Szаthmiry (1995) arguе that all Ьut two of thеsе еight transitions wеrе uniquе, oссurring just onсе in a singlе linеagе.Thе twсl ехсеptions arе thе oгigir-rsof multiсеllular organisms, whiсh happеnеd thrее timеs, and of сolonial animals with stеrilе сastеs'whiсh has happеnеd many timеs. Had any of thе othеr siх trаnsitions not happеnеd, and thаt inсludеs thе origin of lifе itsеlf (numЬеr 1), thеn wе would not Ье hеrе. Thаt only two of thе еight havе dеmonstraЬly happеnеd morе than onсе spеаks against Simon Сonway Morris's (2003) thеsis that с()nvеrgеnсеtn naturе is so prеvalеnt that humanity and mаny othеr еХtаnt stylеs of lifе аrе virtually inеvitаЬlе.

Divеrsifiсation NUМвЕRs Lifе is astonishingly diversе today, with еstimаtеsrаnging from 5 milliсln to 100 million spесiеs, Ьut pеrhaps' п1OrеsoЬеrly, homing in on a 6gurе Ьеtwееn 10 million and 15 million spесiеs(sееthе mаin еssay ..Thе Pattеrn and Proсеss of Spесiation'' Ьy Мargarеt B. Ptасеk and Shala J. Hankison in this vсllumе).Of thеsе,fеwеr than 2 million hаvе Ьееn rесognizеd and dеsсriЬеd so far. It is сommonly assumеd that iifе today is morе divеrsе than it has еvег Ьееn.This sееmsin somе Ways oЬviсlus,Ьut it сould aIso Ье сonstruеd as еxtraordinary vanity, somеhow akin ttl thе viеw that all еvolution was plannеd to lеad to human Ьеiggs, аnd that somеhow this instant in thе vast span of timе is thе most importаnt of аll. Howеvеr, it is еvidеnt that all living organ. isms and ali organisms known as fossils dеrivе fгom а singlе сommon anсеstor (on thе Ьasis of thе еvidеnсе of shаrеd сomplех сharaсtеrs,sr-rсhas thе DNA-RNA systеm of inhеritanсе,homеoЬoх gеnеs,and thе likе). That сom. mon anсеstor, thе singlе spесiеs that gаvе risе tсl all of lifе, ехistеd somе З.5_з.8 Ьillion yеars ago. But how many spесiеshavе еvеr ехistеd? Biologists аnd palеontologistshavе triеd а rrumЬеrof linеs of rеаsonlng to еstimatе thе totаl numЬеr of spесiеs thаt havе еvеr ехistеd. Pеrhaps living Ьiodivеrsity is only 24Y" of thе total that hаs еvеr ехistеd' as is suggеstеdЬy thrее linеs of rеasoning (Sеpkoski 19921Мaу 1994): 1. Thе first argumеnt is Ьasеd on an assumеd pattеrn оf spесiеsdivеrsity inсrеasе аnd thе known avеragе duratiсln of a spесiеs Ьеforе it Ьесomеs еxtinсt. If spесiеsdivеrsity inсrеasеdroughly linеarly (additivе modеl) through thе Phanеrozoiс' аnd аvегagеspесiеsduration is 5_10 million

yеars' thеn living spе thе past 600 million 2. Thе sесond argumеn past 450 million yеa 1 0 m i l l i o n y е a r s ,a n d tеrrеstrial spесiеs tha 3 . Т h е t h i г d а r g u m е n ri s p е с i е so Г f o s s i l m а r i numЬеr of known m; Allowing for nonprеs lossеs,this сould alsс spесiеs (Sеpkoski 19!

In thеsе disсussions it has саtion foг mасrosсopiс o сroЬеs arе ехсludеd Ьесаu and vеry littlе is known of еvеr ехistеd arе alivе todа to 750 million spесiеs rn t

МoDЕLs

Biodivеrsity, thеn, has ехp todаy. But how? Thеrе ar thеsе сan Ье ехprеssеdin t a straight linе, an ехponеI ruptеd inсrеasе (Figurе 1; i m p o s е d ( F i g u г е1 B ) . The liпеаr modеl rеprеs Ьеr of nеw spесiеs in еасh o t h е r s i s a n е t i n с r е a s е ,i . еvolutionaгy ,Ьrаnсhing m timе spесiation гatеs havе larly at a ratе suffiсiеnt to in rhе гаtе of еvolution in t o t а l n u m Ь е r o f s p е с i е si s t h е Ь o а r d г е m a i n s f i x е d ;h o r p r o Ь a Ь i l i г yo f s p l i t t i n g ally Ьееn rеjесtеd as imprс The eхpoпeпtiаl model i tion. If spесiation and еxt will Ье rеgular douЬling < of еvolution at thе lеvеl of nеlltial ratе of inсгеasе ol modеl has Ьееn appliеd to thе divегsifiсation of lifе ir

Pаlеoпtologу апd thе Historу of Lifе пd thе origiп of lсlпguаgе. TЬe pе to human soсiеtywas proЬaЬly ; human lаnguagеis likе thе gеnеa n s m i t t е dw ' i t h m < l d i сf iа t i o n , cn holds soсiеtiеstogеthеr аnd гguеthat all Ьut two of thеsе еight lсе in a singlе linеagе.Thе tW()еxorgаnisms,whiсh happеnеd thrее ] сastеs'whiсh has happеnеd many ls not happеnеd,and that inсludеs е would not Ье hеrе. That only two :d morе than onсе spеаks against e t с o n V е r g е n сiеn n а t u r е i s s o p r е ехtant stylеs o{ lifе arе virtually

yеаrs,thеn living spесiеsrеprеsеnt2-4"Ь of thosе that ехistеd duгing thе past 600 milliоn yеars. 2. Thе sесond aгgumеnt is Ьasеd on thе divеrsifiсationof insесts ovеr thе past 450 million yеars. If thе avеragеduration of an insесt spесiеsis 10 million yеars, and thе group has divеrsifiеdlinеaгly, thеn 5% of all tеrrеstrialspесiеsthat еvеr еxistеd arе alivе today. 3. Thе third argumеnt is Ьasеd on prеsеrvaЬilityof fossils. Somе 250,000 spесiеsof fossil marinе animals havе Ьееn namеd, similar to thе total numЬеr of known marinе animal spесiеsalivе today (200'000). Allowing for nonprеsеrvationof soft-Ьodiеdorganisms and othеr lossеs'this сould also rеprеsеntonlу 2_4Y" of thе total numЬеr of fossil spесiеs(Sеpkoski 1992). In thеsеdisсussionsit has only Ьееn possiЬlе to еxaminе pattеrns of divеrsifiсation for mасrosсopiс organisms, that is, typiсal plants and animals. MiсroЬеsаrе ехсludеd Ьесausеit has Ьееn hard to еstimatе thеir сurrеnt divеrsity, and vеry littlе is known of thеir еarly fossil rесord. If 24% of all spесiеsthat еvеrеxistеdarе alivе today (10-1 5 million), thеrе must hаvе Ьееn somе 250 to 750 million spесiеsin thе past. MoDЕLs

)Stimatеs ranging from 5 million to ioЬеrly, homing in on а figurе Ьеее thе main еssay..Thе Pattеrn and aсеk and Shala J. Нankison in this tavеЬееn rесognizеdand dеsсriЬеd 'y is morе divеrsе than it has еvеr rut it сould also Ье сonstruеd as еxr,iеwthat all еvolution wаs plannеd tow this instant in thе vast span of :r, it is еvidеntthat all living orgЭn|еrivеfгom a singlе сommon anсеs:d сomplеx сharaсtеrs'suсh as thе boх gеnеs,and thе likе). That сomvе risе to аll of lifе, ехistеd somе spесiеshavе еvеr еxistеd? d a n u m Ь е гo f l i n е so f r е e s о n i n gt o t havе еvеr ехistеd. Pеrhaps living ' has еvеrехistеd,as is suggеstеdЬy tlaу |994): ;umеdpattеrnof spесiеsdivеrsity rtion of a spесiеsЬеforе it Ьесomеs roughly linеarly (additivеmodеl) ;еspесiеsduration is 5_10 million

Biodivеrsity,thеn' has ехpandеd from onе spесiеsto many millions of spесiеs today.But how? Тhеrе arе many Ways to go from оnе spесiеsto many' and thеsесan Ье ехpгеssеdin tеrms of thrее mathеmatiсal modеls, rеprеsеntеdЬy a straightlinе, an еxponеntial сurvе' and a logistiс сurvе' first as аn unlntеrruptеdinсrеasе(Figurе 1A), and sесond with somе mass ехtinсtions supеrimposеd(Figurе 1B). ТЬe lineаr modеl rеprеsеnts additivе inсrеasе' thе addition of a fiхеd numЬеrof nеw spесiеsin еасh unit of timе. (Thе inсrеasеin this ехamplе and thе othеrsis a nеt inсrеasе,i.е., truе inсгеаsе minus еxtinсtions.)In tеrnrs of an еvolutionаryЬranсhing modеl, additivе inсrеasе would mеan that thгough timе spесiationratеs havе dесlinеd, or ехtinсtion ratеs havе inсrеasеdrеgularly at a ratе suffiсiеntto mop up thе ехсеssspесiations.Thе impliеd dесlinе in thе ratе of еvolution in thе linеar modеl сomеs aЬout simply Ьесаusеthе total numЬеr of spесiеsis inсrеasingrеgularly, yеt thе rаtе of inсrеasеaсross thе Ьoard rеmains fiхеd; hеnсе,for any individual еvolutionary linе, thе ratе or proЬabilityof splitting (spесiatiоn)must dесlinе. Suсh a modеl has gеnеrally Ьееnrеjесtеdas improЬaЬlе. The ехponепtiаlmodеl is morе сonsistеntwith a Ьranсhing modе of еvolution. If spесiatiсlnand ехtinсtion ratеs rеmain roughly сonstant' thеn thеrе will Ье rеgular douЬling of divеrsity within fiхеd units of timе. A stеady ratе of еvolutionаt thе lеvеl of individuаl еvolutionary linеs sсalеsup to аn еxponеntialratе of inсrеasе ovеrall sinсе total divеrsity is еvеr inсrеasing. This modеlhas Ьееn appliеd to thе divеrsifiсationratеs of individual сladеs and to thеdivеrsifiсationof lifе in gеnеral (Bеnton 1995; Hеwzulla еt a|. 1999|.

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Pаlеrlпtсllog1' апd thе Historу of Lifе

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Figurе l. Thеorеtiсalmtldеlsfсlr thе divеrsifiсаtionof lifе plottеdfrlr thе last 600 million yеars:(A) in thе aЬsеnсеof major pеrturЬаtionand (B) with two п"rass еxtinсtionssupеrimpсlsеd. In еасh сasеthе uppеr сurvе is thе logistiсor еquiliЬriummtldеl' thе middlе сurvе is thе :rdditivеor linеаr modеl,аnd thе ]owеrсurvе is thе схponеntiaIrnodеl.

Thе logistiс mсiеl involvеs onе or morе сlаssiс S-shapеdсurvеs' еaсh соnsisting of an initial pеriod сlf slсlw divеrsity inсrеаsе,a rapid risе, a slowing of thе ratе of inсrеаsе as a rеsult of divеrsity-dеpеndеntdamping faсtors' and thеn a plаtеau сorrеsponding to a limiting or еquiliЬriurrrvaluе. Thе lсlgistiс modеl has Ьееrrusеd to еxplain pattеrns of divеrsifiсatiсlnof marinе organi s r n s( S е p k o s k i1 9 8 4 ) а n d o f p l a n t s ( N i k l a s е t a l . 1 9 8 3 ) . Thеrе is сlеarly n() сonsеnsuson whiсh modеl Ьеst ехplаins thе divеrsifiсation сlf mаiOr sесtorsof lifе thrоugh timе, or on whеthеr all pattеrnsof divеrsifiсation adhеrе to thе samе modеl of inсrеasе. Thе сhoiсе of modеt is imptlrtant sir-rсе еасh makеs prсlfourrdlydiffеrеnt сlaims аЬout еvoluгion.

Thеrе arе major diffегеnс and in thе sеa, and thе his fеrеnt. Today aЬout 85% land, and thе main grouPs p r е s е n t8 r е а t d i v е r s i t y i n t Ьееn еvolving in thе sеa s rесord is dominatеd Ьy m. sсriЬеd forms. This domir by thе faсts that virtually еarly Рalеozoiс (600-450 history of lifе on land apр Also, fossils in сеrtain ma thаn thosе in many сontin d а y i s a p p а r е n t I yf i v е t с l s i of thе insесts' сould Ье an votеd Ьy systеmatists to сl this diffеrеnсе is еvеn pаrt divеrsifiсаtion on land tha In studiеs of thе divеrsif is еvidеnсе for a short pl. yеars) and a longеr onе frс lion yеars). This is follow ехponеntial inсrеаsе in di rising еlеmеnt of a third lo thе last 25 million yеars o aсhiеvеd 125 million yеars Мarinе invеrtеЬratе divt thе suссеssion of thrее m: Ьlаgеs of diffеrеnt phyla . wеrе thеn rерlaсеd. Thе (

and thеn divеrsifiсation slo proaсhеd. Thе ехponеntiа in thе еаrly ordoviсian, rес largеly supplanting thе Сal thе еnd of thе Pеrmian' wJ fauna dгаmatiсally, thе M tеrm risе in divеrsity. In studiеs of thе divеrsif rium intеrprеtation has аls< сеssion of major Bаиpltiпе vasсular plants in thе Dеv< СаrЬonifеrous to thе Pеrm and angiospеrms from thе ing spесiation ratеs and inr

Pаlеoпtoklgу апd tbe Historу of Life LAND AND sЕA сoМPARЕD

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з сlаssiсS-shapеdсurvеs' еaсh сon. g inсrеasе,a rapid risе, a slowing of y-dеpеndеntdamping faсtors, and 3 or еquiliЬrium valuе. Thе lсlgistiс of divегsi6саtion o f m а г i n еo r g e n tsеtal. 1983). modеl Ьеstеxplains thе divеrsifiсaor on whеthеrall pattеrnsof divеrinсrеаsе.Thе сhoiсе of modеl is iffеrеntсlaims aЬout еvolution.

Thеrе arе major diffеrеnсеs Ьеtwееn thе pattеrns of divеrsifiсation on lаnd and in thе sеa, and thе history of lifе in еaсh rеalm may havе bееn rathеr diffеrеnt.Todаy aЬout 85% of dеsсriЬеd spесiеsof plants and animals livе on land' and thе main groups (plants, arthropods, vеrtеЬratеs)havе rеaсhеd thеir prеsеntgrеat divеrsity in thе past 450 million yеars. Plants and animals havе bееnеvolving in thе sеa sinсе at lеаst 600 million yеars ago' аnd thе fossil rесordis dominatеd Ьy marinе spесiеs,whiсh makе up somе 95o%of all dеsсriЬеdforms. This dominanсе of marinе organisms is partly aссountеd for Ьy thе faсts that virtually thе only organisms known from thе Vеndian and еarly Palеozoiс (600_450 million yеars ago) arе marinе, and that thе еarly historyof lifе on land appеars to havе oссurrеd at rеlativеly low divеrsitiеs. Also, fossils in сеrtain marinе еnvironmеnts arе morе likеly to Ье prеsеrvеd than thсlsеin many сontinеnta1sеttings.Thе oЬsеrvation that lifе on land today is apparеntlyfivе to siх timеs as divеrsе аs lifе in thе sеa, largеly Ьесausе of thе insесts,сould Ье an artifaсt that rеflесtsthе grеatеramount of timе dеvotеd Ьy systеmatists to сontinеntal than to marinе organisms. Howеvеr, if this diffеrеnсеis еvеn paгtly сorrесt' thеn it would imply a muсh morе rapid divеrsifiсationon land than in thе sеa. In studiеsof thе divеrsifiсationof marinе animal familiеs (Figurе 2A), thеrе is еvidеnсеfor a short platеau in thе СamЬrian (lаsting aЬout 40 million yеаrs)and a longеr onе from thе Ordoviсian to thе Pеrmian (аЬout 250 million yеars).This is followеd Ьy a long phasе (250 million yеаrs) of nеarехponеntialinсrеasе in divеrsity through thе Меsozoiс and Cеnozoiс, thе rising еlеmеnt of a third logistiс сurvе, whiсh shows a hint of a slowdown in the last 25 million yеars or so, suggеstingthat a third platеau lеvеl may bе aсhiеvеd125 million yеars in thе futurе (Sеpkoski 7984). Мarinе invеrtеЬratеdivеrsifiсationhas Ьееn ехplainеd (Sеpkoski 1984) as thе suссеssionof thrее major phasеs of еvolution, in whiсh Ьroad assеmЬlagеs of diffеrеnt phу|a (еuolutionаrу fаuпаs) dorninatеd thе oсеans and wеrе thеn rеplaсеd. Thе СamЬrian fauna divеrsifiеd еxponеntially at first' and thеn divеrsifiсationslowеd as thе еquiliЬrium lеvеl of 85 familiеs was approaсhеd.Thе еxponеntial divеrsifiсationof thе Pаlеozoiс fauna thеn bеgan in thе еarly Ordoviсian, rеaсhing an еquiliЬrium divеrsity of З50 familiеs and largеly supplanting thе СаmЬrian fauna. Finally, aftеr thе mаss еxtinсtion аt thе еnd of thе Pеrmian, whiсh rеduсеd thе global divеrsity of thе Palеozoiс fauna dramatiсally, thе Мodегn fauna сontinuеd and ассеlегatеdits longtеrmrisе in divеrsity. In studiеsof thе divеrsifiсаtionof vasсular plаnts (Figurе 2B), an еquiliЬrium intеrprеtationhas also Ьееn givеn (Niklas еt аl. 1983). Thеrе was a suссеssionof major Bаиpliiпe (ground plans or arсhеtypеs)of plant typеs:еarly vasсularplants in thе Dеvonian; lyсopods' fеrns' сonifеrs, and othеrs in thе СarЬonifеrous to thе Pеrmiarr; gymnospеrms in thе Triassiс to thе Jurassiс; and angiоspеrmsfгom thе Сrеtaсеous onwаrd. Thеrе is еvidеnсе foг dесlining spесiation ratеs and inсrеasing spесiеs durations during еaсh of thе first

87

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(A), Figurе 2. Pattеrnsсlf divеrsifiсationof fаnriliеsof marinе irrvеrtеЬrаtеs ( B ) , ( С ) , ( D ) . p l a n t s n o n m a r i n е i n s е с t s v а s с u l a rl a n d tсtrapods :rnd StratigraphiсaЬЬrеviations:С, СarnЬrian1СrЬ, СarЬonifеrous;(irеt, Сrеtaсеous;D, Dеvonian;Jur, Jurassiс;O, Ordoviсiаn;P, Pеrrnian;S, Silurian; Tеrt, Теrtiаry;Tr, Triassiс;V, Vеndiаn. (Basеdсln Sеpkoski 1984; Niklаs еt al. 1 9 8 3 ;B е n t o n1 9 8 5 ;a n d l , a Ь а n d е i r a n d S е p k o s k i19 9 З . )

thгее radiations as thе nеw sеt of сladеs partially rеplaсеd thе old. Еaсh nеw radiation lеd to an inсrеasеin.total gloЬal divеrsity,whilе thе divеrsity of thе pгесеdingfloras dесlinеd.Angiospеrms apparеntly сontinuеd tсl divеrsify аt a high ratе. It is hаrd to idеntify platеatrsin land-plant spесiеsdivеrsifiсation, and it is hard to find еvidеnсе for lоgistiс modеls of divеrsifiсation.Еqually, thе total сurvе of spесiеsdivеrsitiеsthrсlugh timе is not oЬviously ехponеntiаl, and, if anything, thе pattеrn appеars tO suggеstlinеаr inсrеasе in divеrsity through timе. Thе divеrsifiсationof сontinеntal tеtrapсldfаmiliеs (Figurе 2С) appеаrs to сOrrеspondtO an ехponеntial rтodеl of iпсrеаsе(Bеnton 1985). Divеrsiry lеvеls rеmainеd low, at somе З0 to 40 familiеs, during thе latе Palеozoiс and muсh of thе Меsozoiс. Thеy thеn rosе to aЬoшt l00 faпriliеsat thе еnd of thе Сrеtaсеous and, after rесovеry from thе еnd-Сrеtaсеous ехtinсti()n еvеnt' f:1milial divеrsity inсrеasеdrapidly toward 330 fаmiliеs and shows rro sign of a slowdown. Thе pattеrn of divеrsifiсationmay Ье dissесtеdinto suссеsstvеradiations of thrее gloЬal сladе аssoсiations:Ьаsаl tеtrapods (formеrly tегmеd

Iаbуriпth o dorul amphiЬiar Palеozoiс; arсhosaurs (dir and lissamphiЬians (frogs Ь i r d s ,a n d m a m m a l s f r o m assoсiations rеplaсе еaсh r milial divеrsity lеvеls,Ьut

сiations. Thе divеrsifiсation of ir еspесially in гhе Mеsozo 1,99З). This suggеsts that еxpansion that pеrhaps sl с a t е t h а t i n s е с t d i v е г s i t yi

Plots of thе divеrsifiсa lifе (Figurе 3) by Bеnton сation. Thе сontinеntal с and land plants' is ехpon lеozoiс platеau lеvеl and ward thе Rесеnt, whiсh l approaсhing an еquiliЬri сontinеntal familiеs (Fig ting еxponеntial сurvе (F flесting thе сontriЬurio сannot Ье ignorеd. ЕxPLANAтloNs

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In сomparing logistiс anr thе kеy distinсtion is Ьеtv modеls. Thе formеr imp\ еxpansion modеls assum lеast that suсh a сеiling h Еquilibrium modеIs fol an influеntial Ьody of еr data on divеrsifiсation as (2) intеraсtions Ьеtwееn< iеs show that сlаdеs ma; ratе of divеrsifiсation slov phеnomеna, suсh as сom duсtion of spесiеs rangеs lows еxpliсitly from сlas of onе population supor sourсе. An initial ехpoп lowеd Ьy a platеau whеI (usually food); this сorrе Thе pattеrn of divеrsif prеtеd (Sеpkoski 1984,

Pаlеontologу апd the Нistorу of Life Iаbуrinthodoпt amphtЬians) and synapsids (mammal-likе rеptilеs) in thе latе Palеozoiс;arсhosaurs (dinosaurs,ptеrosaurs' сroсodilians) in thе Mеsozoiс; and lissamphiЬians (frogs and salamandеrs), lеpidosaurs (lizards and snakеs), birds' and mаmmals from thе latе Сrеtaсеous to thе prеsеnt day. Thеsе сladе assoсiationsrеplaсе еaсh othеr and arе assосiatеd with еvеr highеr gloЬal familial divеrsity lеvеls, Ьut it is diffiсult to fit logistiс сufvеs to any of thе asso-

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aгtiallyrеplaсеdthе сlld. Еaсh rrеw divеrsity,whilе thе divеrsity of thе parеntlyсontinuеdtсl divеrsify at а r land-plantspесiеsdivеrsifiсation' modеls of divеrsifiсation.Еquаlly, gh timе is nсlt oЬviously еxponеntO suggеstlinеar inсrеasеin divеrod familiеs (}.igurе2С) appеаrs to r е a s е( B е n t o n1 9 8 5 ) .D i v е r s i t yl е v . [iеs,duгing thе latе Palеozoiс аnd Ьout 100 familiеsat thе еnd of thе l d - С г е t а с е o uеsх t i n с t i о nе V е n t 'f i r 30 familiеsand shows no sign of a r a y b е d i s s е с t е di n r o s u с с с s s i v ег а : Ьasaltеtrаpods(formеrly tеrmеd

сiations. Thе divеrsifiсation of insесts (Figurе 2D) was also apparеntly еxponеntial, еspесiallyin thе Меsozoiс poгtion of thе сurvе (Labandеira and Sеpkoski 1993).This suggеststhat insесts havе had a long and сontinuous pattеrn of ехpansionthat pеrhaps slowеd somеwhat during thе Tеrtiary. This may indiсatеthat insесt divеrsity is approaсhing an еquiliЬrium lеvеl now. ..all'' Plots of thе divеrsifiсation of fаmiliеs of marinе. сontinеntal. and lifе (Figurе 3) Ьy Bеnton (1995) сonfirm thеsе varying modеls of divеrsifiсation.Thе сontinеntal сuгvе (Figurе 3B), dominatеd Ьy tеtrapods, insесts, and land plants, is еxponеntial. Thе marinе сurvе (Figurе 3С) rеtains a Palеozoiсplatеau lеvеl and appеаrs to show a slowdown in divеrsifiсation toward thе Rесеnt' whiсh may indiсatе that marinе divеrsity lеvеls today arе approaсhingan еquiliЬrium lеvеl. Thе сurvе that сomЬinеs all marinе and сontinеntalfamiliеs (Figurе 3A) сould Ье intеrprеtеd as a singlе poorly fitting ехponential сurvе (Hеwzulla et a|. 1'999),Ьut thе Рalеozoiс platеau, rеflесting thе сontriЬution of marinе invеrtеЬratеs (сomparе Figurе 3С), сannot Ье ignorеd. ЕXPLANAтloNs oF PAттЕRNs oF DlVЕRsIF|сAт|oN In сomparing logistiс and ехponеntial modеls for thе divеrsifiсation of lifе, thе kеy distinсtion is Ьеtwееn еquiliЬrium and nonеquilibrium (or еxpansion) modеls.Thе formеr imрly thе ехistеnсеof gloЬal еquiliЬria in divеrsity,whilе ехpansion modеls assumе that thеrе is no сеiling to thе divеrsity of lifе, or at lеastthat suсh a сеiling has yеt to Ье rеaсhеd. Еquilibrium models forthе ехpansion of thе divеrsity of lifе wеrе Ьasеd on an influеntial Ьody of есologiсal thеory. Logistiс modеling of gloЬal-sсаlе data on divеrsifiсationassumеs (1) intеraсtionsamong spесiеswithin сladеs, (2)intеraсtionsЬеtwееnсladеs,and (3) gloЬаl еquilibrium levеls.Many studiеs show that сladеs may radiatе initially at ехponеntial ratеs' Ьut that thе ratеof divеrsifiсation slows at a сегtain point as a result of divеrsity-dеpеndеnt phеnomеna,suсh as сompеtitivе еxсlusion, inсrеasеd spесiеs paсking' and rеduсtionof spесiеsrangеs (Sеpkoski 1,984,1'996).This stylе of rеasoning follows еxpliсitly from сlassiсal еxpеrimеnts in сompеtition whеrе thе inсrеasе of onе populаtion supprеssеs anothеr that dеpеnds on thе samе limiting rеsourсе. An initial ехponеntial inсrеasе of thе suссеssful population is followed Ьy a platеau whеn thе spесiеs Ьеgins to dеplеtе thе limiting rеsourсе (usuallyfood); this сorrеspondsto thе loсal сarrying сapaсity. Thе pattеrn of divеrsifiсation of marinе familiеs (Figurе 2A) has Ьееn intеrprеtеd (Sеpkoski 1984' 1996) in tеrms of a thrее-phasе logistiс modеl that

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Figurе 3. Pattеrnsof thе с in numbеrs of familiеsеx (A)' сontinеntalorganism mахimumand а minimur tn and haЬitat-prеfеrеnсе familiеsгесordеdas dеfin d е f i n i t е l ys p а n n i n gt h а t s thе mагinе or сontinеnta doubrful strаtigrаpЬiсаtt haЬitat dеsignations.Thе organismsis еqual to thе m а х i m u m m е а s u r е sh, o w tаха Ьесausеfamiliеs wit] oссur in Ьoth marinе аnd сontinеntal.Stratigrаphr Centlzоiс;Pс' Prесаmbгtа

Pаlеontologу аnd tbe Historу of l-ifе rеprеsеnts thе Ьеhaviorof thе tlrrеееvolutionaryfaunas:Сambгian, Pаlеozoiс, аnd Мodеrn. Thе rеplaсing furunasarе said to hаvе Ьееn сhаraсtеrizеd Ьy thе aЬilityto pеnеtratееvеr widег sеts of niсhеs and hеIrсеtсl aсhiеvе highеr divеrsitiеs.Thеrе is somе еvidеnсеin favor of this idеа; for ехamplе, lаtеr maritrе an. imalsсould Ьurrow dееpеr,fсlrm morе сornplеx rееfs,and сapturе prеу in еvеr morе ingеnious Ways. Thе еquiliЬrium rnodеls сould Ье intеrpгеtеd sirnply in tеrmsof largе-sсalесompеtition Ьеtwееn major сladеs' with Ьivalvеs outсompеtingЬrасhiopods,пrammаlsoutсompеtingdinosаurs,and sсl on. Dеspitе thе pоpular:rppеalof suсh suggеstions,mosr supposеdсаsеsof largе-sсаlесompеtitionсrumЬlеwhеn thе еvidеnсеis еxaminеd (е.g.,Gould and Сalloway 1980; Bеnton1987). Sеpkoski (1996) attriЬutеdthе pattегnsof waхing and waning of сladеs to diffrrsе сOmpеtition Ьеtwееn thеm at thе spесiеs lеvеl, whеге spесiеsin onе сladе arе gеnеrally сompеtitivеly sr"rpеriorto thosе in anothеr. Howеvеr,thеrе arе four arеas of сonсеrn with еquiliЬrium modеls:

Itime 200

100

i. Тhеге is no indеpеndеr-rt еvidеnсе for еquiliЬria, that is' for fiхеd саrrу.ing сapaсitiеson thе еarth today. In еvolutionary tеrms еquiliЬrium divеrsitiеsimply that all availaЬlе rеsourсеsarе in usе and all есospaсе i s f i l l е d .I f a n е w s p е с i е sо r i g i n а t е s ,i t m u s t d i s p l a с еa p г е е х i s t i n go n е . Howеvеr, oЬsеrvаtionsof сasеs whеrе prеviously isolаtеd floras and faunasсomе into сontaсt suggеstthat spесiеsarе just as likеly to insinrratе(еntеrnеw niсhеs) аnd not сausе еxtinсtion of othеr taХa' 2. Мultiplе logistiс mоdе[s imply prеdiсtаЬlе outсomеs of intеraсtiorrs Ьеtц,ееnmеmЬеrsof thе diffеrеnt faunas. that is. that nrеmЬеrsof onе .!Иherе gгoup will gеnеrallysuссееdwhеrе thosе of аrrothеrwill fail. majоr Ьiotiс rеplасеmеntshаvе Ьееrrinvеstigirtеd,onе group is moге likеly to disappеar Ьесausеof an ехtinсtion еvеnt (Bеnton 1987) than а s а r е s u l to f i n t е r a с t i o n s .

r lt i m e 200

'r00

Jur Сret

Figurе З. Pattеrns of thе divеrsifiсation oi lifе thrсlugh timе in tсrms of сhangеs in numЬеrs of fаmiliеs ехtant реr strаtigraphiс stagе, plоttеd for all organisms (A), сontinеntal orgаnisms (B), аnd marinе organisms (С). In еaсh grаph a mаximunr аnd а minimum arе slrown, Ьasеd on a сot-r-rЬination of strаtigraPhiс and haЬitаt.prеfеrеnсеinforn-ratiоn.Thе minimum mеasurе inсludеs or-rlу familiеsrесordеd as dеfinitеly prеsеnt within еaсh stratigrаphiс stagе or as definitеlyspаnning tЬat stagе, and only fаmiliеs dеsignatеd as rеstriсtеd solеly to thе marinе or сontiDеlltаl rеаlm. Thе mахiInr.rmmеasllrе inсludеs trlso all douЬtfLrlstratigraphiс attriЬutions of familiеs and аll еquivoсal аnd sharеd haЬitatdеsignations.Thе sum of minimum mеasurеs fоr сontinеntal аnd rnaгinе organismsis еqual to thе minimllm mеasllге for all taxa togеthеr. Thе sum of mахimuпr гIlеasllrеs'h
9]

e2 Раlеoпtrllog1'апd thе L{istorуof Lifе 3. Thе dir.еrsifiсationof thе Mtrdеrn fаunа sееnrsmorе prol()ngеdand slorvеrthan prеdiсtеd Ьy a ltlgistiс mtlr']еl.Thе rising phirsеof thе logistiс сuгvе has lastес]for 2.50 million vеars,with somе еvidеnсеof a slowdown toward thе pгеsеnt.If thеге is no сшrrеntplatеau,thеn it would Sееmthat in thе sесond half of thе Phanеrozoiс,thе Ьеst-known part ()f t[rеfossil rесord, thе logistiс rulеs lr:rvеЬееn forgсlttеn. 4 . T h е с l а s s i сl o g i s t i сс u r v е sо i S е p k o s k i( 1 9 8 4 , l 9 9 6 ) m a v Ь е a r r i f a с t so f thе lеvеl of analysis.Тlrе сurvеs arе plt>ttеdat thе lеvеl of fanriliеs. \iИhеnthеsе arе translatеdto thе gеnеriс lеvеl, thе logistiс pаttеrns Ьеgin to Ьrеak down, and at spесiеslеvеl thе pаttеrn сoulс1Ье ехponеlltiai (Bеnton 1997). Thе shapе of thе сurvеs switсhеs Ьесausе еaсh gеr-rr.rs сontains manУ spесiеs,and еaсh fаmily many gеnеra.In an еvoltrtiсlnаrytrее thе spесiеsarе thе tir-rlrl twigs, whilе gеnеra ехtеnd dееpегinto thе trее, аnd fаmiliеs dееpеr still. So, althouglr thе numЬеr of familiеs might Ье dеfinеd аt a сonstant lеvеl, thе nr-rmЬеrof spесiсs in еeсh сould Ье ехpandirrgехponеntiall},. Thе аltеrrrltivе to еquiliЬгiurrris ехpс|t1sioп. Arе tlrе ill]glеeаtеPattеrns,oI at lеast stlll-lесlf tlrеm (FigLrгеs2 and 3), tЬе rеsult of unсotrstrainеdехpansiorr? Сеrtailrly, somе сlаdеs (suсh as insесts,angiospеrms,Ьiгds, and mаmnrals) sееm tсl сontinuе rаdiating linеarly or ехponеntially for many tеns or h u n d r е d s t l f r n i l l i o r r so f y е a r s . S u с h е v е r - е x p a n d i n gp a t t е r n s i m p l y t h a t t h е s е g r < l u p sa r е h i g h l y s u с с е s s f L ral n d a d а p t : r Ь l е Т . h е o v е r а l l p : 1 t t е r n so f divеrsifiсation (Figurе З) iпссlrporatеthе n[tllеr()usсonstitllеnt сladеs, sotте ехpanding' tltЬеrs diminishirlg, аnd othеrs rеrnainingat сonstilnt divеrsity аt any Partiсul:rrtimе. From an ехpensionist viеwpoint, thеrе is no prеdiсtion of how thе individual сladеs irffесt еaсh othеr. Nеw gloЬа1 divеrsity lеvеls mаy Ье aсhiеr,еdЬy сomЬinatithе numЬеrs of familiеs or othеr taхa that сan inhaЬit thе еllrth at any timе: suсh a limit rvould Ье сausеd not lеast Ьy thе аmount сlf srаndirrg room on thе ark. If a limit of living spl1сеWсrе aPprсlaсhеd'еvеr smallеr tlrganisnrswсluld prеsuпraЬlvЬе fаvorеd Ьv sеlесtion. Еquallr., аs Ьirs happеnеd llrlrny tinlеs сlrrringеvtllr'rtion,trrgelnismswould takе unехpесtеdmеasurеsto survivе, for ехirnrplс,Ьy oссupying thе аir' Ьurrсlwing into sеdimеnts,and, ill thе сasе of sonrе Ьaсtеria,living dееp within thе еarth's сrllst. With sizе rеduсtion, thе ultimatе linrit to thе divеrsifiсation of lifе might thеn Ьес
Е Q U l L | B R l U l " 1o F

It is hard to sеlесt bеtwi til rесеntly, еquiliЬrium gists, just as thеy hаvе с есologists arе now quеst сеptеdin the 1960s and versifiсation might havе Thе еquiliЬrium mod, aссommodatе only сеrt; саpaсity is rеaсhеd, nеt no sцсh assumрtion аn with no ultimаtе limit iп PalеoЬiologists havе < rесt. Реrhaps all lifе has еxpansion modеl (Stanlс fiеd in diffеrеnt wаys. I lеvеl of staЬilitу, and pz whilе lifе on land lnay and arthropods сrеpt с: еquiliЬrium and еxpans p а l е o Ь i o l o g i s t s ,Ь u t Г o r statе of gloЬal Ьiodivеrs

Spесiation

Тhе еffort to undеrstаnd is at thе uppеr еnd of thе еnd thе important сross< studiеs is spесiаtioп (see

tion'' Ьy Маrgarеt B. Pt mation of nеw spесiеs b' PаlеoЬiologists сlеаrlу сannot tеst whеthеr any thеy sееk to apply thе r distinguishеd Ьy diffеrеr a wеak suЬstitutе,Ьut th ulаtional thinking, sееk t tistiсаl studiеs of lаrgе invoIvеs morphologiсаl tion. In pгaсtiсе' this is п atists of modегn oгgаn from morphology, and I lеss studу. Systеmatistsr

Pаlеontologу апd thе Нistorу of Lifе la sееmsmоге prolongеd and dеl. Thе rising phasе of thе n Yеars'with somе еvidеnсеof t.t is no сurrеntplatеatr,сhеn it thе Phanеroztliс' thе Ьеst-known lеs havе Ьееrrforgсlгtеn' ( | 9 8 4 , 1 9 9 6 )n r a y Ь е a r t i f a с t so f эttеdat thс iеvеl of fаnriliеs. iс lеvеl, thе logistiс pitttеrns vеl thе pаttеrnсoulс]Ье of thе сurvеsswitсhеsЬесausе l еaсh familv many gеnеra.In arr rаl twigs,whilе gеnеrаехtеnd jr still. So, although thе numЬеr ant lеvel' thе nuпrЬеrrlf spесiсs r Il1'. oп. Аrе thе aggrеgatеpattеrns' or l е г е s u l to f u п с o n s t r a i n е dе х p a n rs, angiospеrms,Ьirds, and nr:rm_ )r еxponеntiallyfor many tеns or г-ехpanding pаttеrns imply thаt laptаЬlе.Thе ovеrаll pаttеrrrsof umеrousсonstituеntсladеs, somе rеrnaining at сonstant сlivеrsity аt viеwpoint, thеrе is rro prеdiсtion lthеr. Nеw gloЬal divеrsity lеvеls rdaptations,haЬitat сhangеs,arrd 'еагs thе dil,еrsifiсatiсlnof lifе has rrsоf сеrtair.r сlаdеs Ьoth in thе sеa (insесts, on land ar;rсhnids,anеvidеnсеthаt thеsе rnlrjсlrсladеs : ; l t еt h a t t h с v w i I I n o t с О n t i n U еt o livегsifiсatioI.r wotrld lаst forеvеr. of famiiiеsor othеr tахa that саn would Ье сausеd not lеast Ьy thе a limit of living spaсr Wеrе apеsumaЬlyЬе favorеd Ьy sеlесti
Е Q U I L l B R I U Мo R Е Х P A N S | o N ? It is hard to sеlесtЬеtwееnthе two modеls for tЬе divеrsifiсationof lifе. Until rесеntly,еquilibrium modеls havе dominatеd thе thoughts of palеoЬiologists'just as thеy havе dominatеd thе minds of есologists.Howеvеr, just as есologistsаrе now quеstioningthе ovеrsimplistiсеquiliЬritlпrmodеls thеy aссеptеdirr thе 1960s and 1970s, so palеoЬiologistsаrе rесonsidеrirrghow divеrsifiсationmight havе happеnеd in thе longеr tеrm. Thе еqrrilibriummodеl аssumеs that spесifiс nrajor есologiсal realms саn aссommodatеorrly сеrtain numЬеrs of spесiеs,аnd th:rt whеn thе саrrying сapaсityis rеaсhеd, nеt divеrsifiсation сеasеs.Thе ехpansion modеl makеs no suсh assumptioп and allows for сontinuing, if еpisodiс, divеrsifiсation with no ultimatе lirnit in sight. Palеobiologistshavе dеЬаtеd arrd сontinue to dеЬatе whiсh modеl is сorrесt.Pеrhaps all lifе has divеrsifiеd aссording tсl еithеr an еquiliЬrir.rmor an ехpansionmodеl (Stаnlеv 2007). Or pеrlrapsdiftЪrеntsесtors of lifе divеrsifiеd in diffеrеnt Ways. Еvolution in thе sеa mаy havе rеsultеd in a grеatеr lеvеlof staЬility, and pattеrns of inсrеasе may havе gеnеrally Ьееn logistiс, whilе lifе on land may havе divеrsifiеd ехponеrrtially sinсе thе first plants and arthгopods сrеpt сautiously out of thе watеr. Thе impliсations of thе еquiliЬriumand ехpansion modеls arе profoundly diffеrеnt, not mеrеly for palеoЬiologists,Ьut for еvеryonе сonсеrnеd aЬout thе presеnt and futurе s t a t еo f g l o Ь a |Ь i o d i v е r s i 1 1 ' .

Spесiation Thе еffort to undегstand how lifе diversrfiеd fron-lits oгigir-rto thе prеsеnt day is at thе uppеr еrrd of thе speсtгuпr of studiеs ilt lпаcroеuolutiсэll.At thе lowеr еnd thе important сrossovеr ЬеtwееnpalеoЬiology and nrodеrn еvolutionary studiеsis spеciаtirln(sееthе main еssay ..Thе Pattеrn and Proсеss of Spесiаtion'' Ьy lvlargаrеtB. Ptасеk аnd Shаlа J. Нankison tn this volumе), thе formation of nеw spесiеsЬy thе splitting of liпeаgеs(еvolutionarylinеs). PalеoЬiologistsсlеarly сannot usе thе biologiсаl speсiеsсoпсept sinсе thеy сannottеstwhеthеr аny two fossil spесimеnsarе сapaЬlе of intеrЬгееding,so thеy sееk to apply tЬe mсlrphologiсаl spесiеs сoпсept, in whiсh spесlеs arе distinguishеdЬy diffеrеnсеsin thеir phеnotypеs'This may at first sееm to Ье a wеak suЬstitutе,Ьut thеrе :rrеshaгеd assumptiOns:palеobiologistsusе populationalthinking, sееk to сhаraсtеrizеspесiеsboundariеs on thе Ьаsis of statistiсal studiеs of largе samplеs of spесimеns' and assumе that spесiation invоlvеs morphologiсal diffеrеntiаtion assoсiatеd with rеproduсtivе isolаtion.In pгaсtiсе,this is not vеry diffеrеntfrom thе approaсh of many systеmatistsof modеrn organisms-spесiеs of mollusks are gеnеrally dеtеrmined from moгphologу, and fossil and ехtant matеriаl may form parts of a sеam. lеssstLrdy.Systеrnаtistsrarеly саrry out itltеrЬrееdingtriаls.

9З

Pаleoпtologу апd thе Histor1,of Lifе Until 1970 most еvolutionists assumеd tlrаt fossils с
|\,4oгphoIo9y

F-igurе4. Соntrastingеxpесtatiorrs of spесiеs.lеvеl еr.сllutionill thе с[lsьiс plrylеtiс-grасlr'talisn-r modеl (A) and tl-rеpunсtuаtеd-еquiliЬгiuш modеl 1B). Dеgrееof nltlrphologiсalсlrаngеis indiсаtесlon thс х-ахis, tit-t.lс thе 1,-1y1,. t.lt.t

Thе punсtuatеd-еq 1970s and 1980s was tagonists kеpt shifting Ь a s е do n t h е i d е a s i п еrаl supportегs of pun. idеa of speсies sеlесtio and' in somе modеls, ordеr сharaсtеrs. Spе< and еvеn in oppositio idеa of an ..ехpansior (Gould 1990), with h Darwinian viеw. Suсh most еnthusiasts, and natural sеlесtion duriп ally сonsidеrеd to Ье t, to rеsult in signifiсant tion of individuals. Hс dеnсе pointеd to its irп to еxplain it (Landе 19 A plеthora of сasе |99О that purpoгtеd еquiliЬriumviеws.Е.ar not provide еnough еv of migrаtionsof tаxа i whаt was a graduаl i stеppеd, punсtuationa 1981; Shеldon 1987) t intеnsе foсus on finе-sс thеy wеrе still suЬjесt triloЬitеs showеd a grе agеs just did not spес mеntеd a numЬеr of pu intеrprеtеd as morе lik nonBеnеtiс сhangе in sl Тhе fossil rесord dеr and Anstеy (1995) sur tегns in thе fossil rес. гangеd from radiolаriа stratigraphiс agеs rang iority сonсеntrating in of thе еarth. of thе .5 with anagеnеsis (15 с 6 3 % ) . I t s е е m sс l е a г , t and it had not Ьееn prе Whаt thеn of thе pr Ьatе? As еvеr. thе Drс

Pаleoпtologуаnd thе Historу of Lifе ] thirt fossils сould say vеry littlе а n d G o u i d \ \ 9 7 2 ) с h a l l е n g е dt h е )y punсtuatеdеquiliЬria. Еldrеdgе ft pЬ1,lеtiсgrсtduаlisnt.It assumеd ariaЬlеratеs (Figurе 4A) Ьut wеrе иestЗ/.SpесiationWas sееn as a Ьynеs liпеад1еs had Ьесomе so diffеrrd еvolvеd into a nеw spесiеs (thе .ting (сlаdogezesls/сould aisсl haplstеr than noгmal ratеs of linеagе pиltсtuаtеdеquilibriа (Figurе 48), е at сladogеnеsis,rilthеr th:rn аnaThе normal statе Of a linеagе was ;pесi:rtionш.tluldhappеn. Ьut suсh 'nary. Thе punсtuatеd-еquilibrium rgе along a linеagеаге punсttlatеd' ;pесiаtionеvеnts.Тlrе latrеr сlaim r rеgaгdеdаs thе kеу' dеfinir.rg еlеt Ьy its supportеrs. ldеl on trд,ooЬsеrvatioпs: F o s s i l sс l n г е n l а i nС t r t l 5 1 д1n',' еdir-t-rеr-rt (i.е., tlrotlslrrrdsсlr g sееmsto сhangе. tо Мayr's аllopаtriс (gеograрhiс. a s a r a p i d с v е n ti n thе fossil rgеnсеof two isolatеdpopulations

l\,4orphology

-lеvеlеvolutionirrthе сlаssiс u а t е d - е q u i l i Ь r i rm rm o d е l( B 1 . t l r lt h ех - а х i s .t i m еt r nt h е y - . r х l s .

Thе punсtuatеd-еquiliЬгium vеrsus pЬylеtiс-gгаdualism dеЬatе of thе |970s and 1980s was hugе fun for all сonсеrnеd' nоt lеast Ьесausеthе protagonistskеpt shifting ground and rеvising thеir сlaims. Thе first phasе wаs Ьasеdon thе idеas in Еldгеdgе and Gould's еssays' From 1975 onward sеvеralsupportеrsof punсtuatеdеquiliЬria еxtеndеdthе modеl to еspousеa nеw idеa of spесiеssеlесtion, a highеr_ordеr proсеss in whiсh spесiеs wеrе sortеd and' in somе modеls, сould evеn undеrgo sеlесtion of ..emеrgеnt'' highеrordеr сharaсtеrs. Spесiеs sеlесtion сould, in thеory, oссur indеpеndеnt of, and еvеn in opposition to' natural sеlесtion (Stanlеy 1975). This lеd to thе idеa of an ..ехpаnsion'' of еvolr.rtionarythеory to many hiеrarсhiсal lеvеls (Gould \990), with hints of an apparеnt rеjесtiоn of aspесts of thе nеoDarwinian viеw. Suсh еxtrеmе positions wеге aЬаndonеd fairly rapidly Ьy most еnthusiasts,and palеoЬiologistsсontinuеd thеir staunсh adhегеnсеto naturalsеlесtionduring thе latе 1980s and 1990s. Spесiеssеlесtion is gеnеrally сonsidеrеdto Ье thеoгеtiсallуpossiЬlе Ьut ехtrеmеly fееЬlе and unlikеly to rеsult in signifiсant adaptations of thе typе that oссur in thе natural sеlесdon of individuals. Нowеvеr, thе notion of stasis stuсk: too muсh fossil еvidеnсеpointеd to its imp
95

Pаleoпtologу аnd the Ilistorу of Lifе uЬiquity of thеir modеl, and yеt сommon sеnsеSuggеststhat thеrе arе сlеar Ьiologiсal rеasons that еaсh modеl prеvails undеr pаrtiсulaг сirсumstanсеs. Bеnton and Pеarson (2001) notеd that spесiation is a сonsеquеnсеofrеproduсtivе isolation, and hеnсе thе frеquеnсy of spесiation in a grсlup is likеly to bе rеlatеd to thе еasе with whiсh rеpгoduсtivе Ьarriеrs аppеаr. At onе ехtrеmе thеrе arе organisms suсh as planktoniс protists that livе in hugе pсlpulations that sеldom еnсountеr Ьarriеrs to dispеrsal, and that do not possеss сomplеx bеhaviors assoсiatedwith rеproduсtion. For thеsе,gеnеtiс isolation of populations is a rarе еvеnt, and spесiation,whiсh pеrhaps oссLlrsrarеly' is probaЬly gеnеrally long tеrm and gradual, lasting pеrhaps half а million yеars. At thе othеr еxtrеmе arе organisms suсh as frеshwatеr fishеs that livе in spatially struсturеd and oftеn-transiеntеnvironmеnts. Неrе spесiation might bе so сommon that еvеry lakе and rivеr has its own rеproduсtivеly isolatеd population of a partiсular typе
Rhizosolenia (p|anktoniсdiatom)

5.0 4.0 3.0 2.O

2.8

fТr |

"GAUss

t\

Figurе 5. Grаdual spесi morph
ассount thе gеnеtiсs z rеlatеd еxtant spесiеsа p h o l o g i с а| d i f f е r е n t i a dolоs sееms гo havе Ь was еspесially гapid fr< pеaring in that timе, а agе. Нowеvеr, thе intе Ьy information from ] thеrе arе quеstions ovе vаl. thе oгigins of thе arе more сonfidеntly d Thе pluгality of еvс ism plus stasis, punсtu vironmеntal сontrols l ( | 9 9 6 | p г o p o s е dt h а г ; е n v i г o n m е n r sa n d с h a

Pаlеoпtologу апd the Historу of Life sеnsеsuggеststhat thеrе aге сlеar s undеr paгtiсular сirсumstаnсеs. :iation is a сonsеquеnсеof rеprolf spесiationin a grоup is likеly to 'сtivе barriеrs appеar. At onе ехriс protiststhat livе in hugе popuiispеrsal,and that do not possеss rсtion.For thеsе,gеnеtiс isolation 'n, whiсh pеrhapsoссurs rarеly, is ,l' lasting pеrhaps half a million suсh as frеshwatеr fishеs that livе vironmеnts.Hеrе spесiation might ls its own rеproduсtivеlyisolatеd hesepopulationsmight nеithеr Ье еn might liе thе majority of invеrх h i Ь i r i n gs t a s i sb u t f r o m t i m е t r l ' rеsultof a major pеrturЬation in

Rhizosolenia (p|anktoniс diatom)

rсing animаls that livе in variеd е с i а t i o n .М е l r а r а b d o t o si s a n a s lrеsеntеdtoday in thе СariЬЬеаn iniсan RеpuЬliс and еlsеwhеrеin )n yеars of sеdimеntationin shalf this Ьryozoan.Тhе fossils show from 8 to 4 million yеars aЕ]o' h had diеd out Ьy thе Quatеrnary ln (1995)havе еstaЬlishеda varivtthin Меtr аrаbdotсls, taking into

R. bergonii

l

R. prаebergonii

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protist is sееn in Rbizosoleпiа, a ;еaЬundanсеin thе еquatorial Pavalvеsof this gеnushavе aссumu. d thеy hаvе Ьееnsamplеd Ьaсk to mplеs of thе valvеs сan Ье takеn pilе, and thеsесan Ье datеd aссuosoleniаliving sidе Ьy sidе in thе nd thеsесan Ье traсkеd Ьaсk for l 3.1 million yеars ago' thе morfusе,and thеrе is apparеntly only ). This splitting еvеnt is rеported morphologiсal divеrgеnсеoссurs ,аs еvidеntlynot a loсal еvеnt Ьut iс. Diatoms gеnеrаlly rеproduсе lхual offspring. Pеrhaps thе сomе modе and thе ЬarriеrlеssPaсifiс d phylеtiсally and сlvеr a span of

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Figurе.5.Grаdual spесiationin thе diatom Rhizosolеniа.Onе of sеvеral morphologiсalсhаraсtеrs,thе Ьеightof thе hyalinеаrеa' that diffеrеntiatеthе two living spесiеsR. bergoпii and R. prаеbеrgonii.This plot' from onе of еight saшplingstationson thе floor of thе Paсifiс Oсеan, shows a long-tеrm Ьеtwееnthе two spесiеsfrom 3.1 to 2.6 million yеars ago, as the divеrgеnсе Thе sеdimеntaryrесord is сontinuous,and it populationsslowly diffеrеntiatеd. indiсatedin thе сan Ье datеdЬy fossilsand Ьy magnеtiсrеvеrsalmеasuгеmеnts, masnеtoсhronsсalеat thе Ьottom.

ассount thе gеnеtiсs and thе amount of morphologiсal diffеrеntiation of rеlatеdеxtant spесiеsand thеn еxtеnding сomparaЬlе statistiсaltеstsof morphologiсal diffеrеntiation to thе fossil forms. Linеagе splitting jn Меtrаrаbdolсls sееms to havе Ьееn rapid and punсtuational in сharaсtеr. Spесiаtion was еspесiallyrapid from 8 to 7 million yеars ago' with ninе nеw spесiеsappеaring in that timе, although sampling may Ье a proЬlеm in roсks of this agе.Howеvеr, thе intеrval from 8 to 4 million yеars ago' rеprеsеntеd largеly by information from Dominiсa, has Ьееn intеnsеly samplеd. So, although thеrеarе quеstions ovеr thе origins of thе ninе Ьasal spесiеs within this intеrval, thе origins of thе rеmainder (teпие,nеw spесiеs 10, and nеw spесiеs 8) arе morе сonfidеntly doсumеntеd аs Ьеing punсtuational. Thе plurality of еvolutionary modеs (gradualism without stasis, gradualism plus stasis,punсtuation plus stаsis)might Ье rеal, and thеrе might Ье еnvironmеntal сontrols that work in a somеwhat unеxpесtеd way. Shеldon (I996) proposеd that gradualism might сhаraсtеrizеtaхa that livе in staЬlе еnvironmеnts and сhangе in linе with slow еnvironmеntal сhangеs, whеrеas

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Figurе 6. Punсtuational spесiаtionin thе ЬrусlzoanМetrаrаbdo,os' Thе thrеe living spесiеsаrе doсumеntеdЬy fossils,Ьut a furthеrnine spесiеsarе еxtinсt. Intensесollесtingthroughoutthе СariЬЬеanhas rеvеalеdthе pattеrnof spесiation.Samplingin thе timе from 25 to 8 rnillionyеarsago is sporadiс,Ьut thе timе from 8 to 4 million yеars ago, thе Dominiсan Sampling Intеrval (DSI), is еxtremеly wеll known' Ьasеd on a finе and сontinuous fossil rесord on thе island of Dominiсa. Spесiеsdistinсtionsаrе Ьasеdon a сomЬinаtionof morphologiсaland gеnеtiсstudiеs.

stasis might bе a fеaturе of taxa that oссupy unstaЬlе еnvironmеnts' whiсh сan vary rapidly and dramatiсally, Ьut thosе taхa do not еvolvе in linе with е v е r y е n v i г o n m е n t a fIlu с t u a t i o n '

Quality Thе quality of thе fossil rесoгd has oЬsеssеdand сontinuеs to oЬsеsspalеoЬiol. ogists. Еvеr sinсе Dаrwin (1859, 279) considеrеdthе ..impеrfесtionof thе gеo. logiсal rесord,'' palеobiologists and othеrs havе osсillatеd in thеiг сonfidеnсе. Somе havе сlaimеd, pеrhaps rathеr wildly, thаt еvеrything thе fossil rесord says is сorrесt, whilе othеrs, pеrhaps еqually wildly, havе rеiесtеd thе fossil rесord as bеing nеxt to usеlеss.Thе truth prеsumaЬly liеs somеwhеrе Ьеtwееn' and most pеoplе taсitly vееr to thе positivе еnd of thе spесtrum. A numbеr of ma. jor сhallеngеs havе arisеn rесеntiy' howеvеr, and I shall touсh on thеsе briеfly.

A quаlitativе аrgun nothing Inuсh nеw hа was Stillin 1859 аrgu urian rеptilеs and Dе. rеturn to еarth. DarW сollгsе' аnd hе knеw а vonian, amphiЬians ir in thе Тriassiс, zrnd m. 1 8 5 9 , a n d d е s p i t еt h е havе simply adjustеd has Ьееn pushеd Ьасl phibians from thе еar rеptilеs fгorn tlrе еаrl of mаmmals frorrr tht has rеmainеd unсhan lеssly unrеprеsеntativ to timе. Thе notion of a got by Мaхwеll arrd Bеntr of thе mаrinе animal l knсlwledgе from 1890 Ьoth сasеs thе sum tot Ь l i n g i n 1 0 0 y е a r s ,Ь u to timе, and sсl thе rеmainеd unaffесtеd. whеthег nеw fossil dis Thеу found thе formс thе сomplеtеness of tl morе oftеn thаn сrеet Тhеге havе Ьееn tw sampling еffесts zrrrdl thаt thе fossil rесord а light thе faсt thаt thе wеll known it is, thе { Ьodiеd oгgarrisrnsadе h z r p sl i v i n g i n u n u s u а l Thе сritiсisms of sa (2001,2007) arguеd гoсk rесord, whiсh itl posеd ехtinсtion еvеl thеrе is a major rеgrеs parеntly disappеar frt Ьut it is mегеly а sеdir еvеr, that thе divеrsifil is pгoЬaЬly rеal Ьесar v е r s i t yi s n o t d r i v е n Ь

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юzoanМеtrаrаbdotos.Thе thrее a furthеrninе spесiеsаге ехtinсt. has rеvеalеdthе pattегnof 8 million yеarsago is sporadiс,Ьut )ominiсanSamplingIntеrval(DSI), l сontinuousfossil rесord on thе Ьasеdon a сomЬinаtionof

upy unstaЬlееnvirоnmеnts,whiсh osе taхa do not еvolvе in linе with

l аnd сontinuеsto oЬsеsspaleoЬiolidеrеdthе ..imperfесtionof гhе gеohavе osсillatеd in thеir сonfidеnсе. hat еvеrythingthе fossil rесord says ldly, havе rеiесtеdthе fossii rесord rably liеs somеwhеrе Ьеtwееn, and of thе spесtгum.A numЬеr оf maг' and I shall touсh on thеsе bгiеfly.

A qualitativеaгgumеntfirst, in favor of thе fossil rесord, is thаt sinсе 1859 nothingtnuсlrnеw has сlrifеrous. rеptilеs in thе Pеrmiаn, dinosauгs in thе Triassiс,аnd maпrtnaisand Ьirds in thе Jurzrssiс.In thе 150 yеars sitrсе 1859,and dеspitеthе input of millions of hours of sеarсhing,palеontologists havеsimply adjustеdthе rrrid-Viсtorianpiсturе: thе origin of agnаthan fishеs has Ьееrrpushеd Ьасk from thе Silurian to thе СаmЬrian, thе origin of amphiЬiansfrom thе еarly СarЬonifеrous to thе latеst Dеvonian, thе origin of rеptilеsfronr tlrе еarlу Реrmian to thе rrrid-СarЬonifеrous, arrd thе origin of mammals from thе mid.Jurassiс to tlrе latе Triassiс. Thе origin of Ьirds .!7еrе hаs rеmаinеd unсhangеd in thе latеst Juгаssiс. thе fossil rесord hopе. r-rеwfinds should providе mаjor surprisеs from timе lеsslyr.rrrrеprеsеtltativе' to timе. Thе notiсln of a gotrd fossil rесoгd was сonfirmеd in quantitativе analysеs Ьy Мaхwеll and Bеnton (|990) сlf thе vеrtеЬratеrесord arrd Sеpkoski (199З) оf thе milrinе аnimal rесord. Thе first authors lookеd at thе aссumulation of knowlеdgеfrtlm ] .990 to 1987, thе sесond аt сhаngеs from 1982 to |992. In Ьothсasеsthе sum totals of divеrsity through timе inсrеasеd,еssеntiаllydouЬling in 100 yеars, Ьut thе inсrеаsеswеrе randomly distriЬutеd with rеspесt to til1-lе,and stl thе ovеrаll pаttеrns of divеrsifiсations and ехtinсtions rеmainеd unаffесtеd. In a furthеr study Bеnton and Storrs (1994) tеstеd rvhеthеrrrеw fossil disсovеriеstеnd to fill prеdiсtеd gaps or сrеatе nеW gaps' Thе,vfound thе formеr: in 25 yеaгs of study, nеw fossil finds haсl improvеd thе сomplеtеnеssof thе tеtrapod fossil rесord Ьy somе 5% Ьу plugging gаps morе oftегtthаn сrеating llеw saps. Тhеrе havе bееn two rnajor сhallеngеsto this somеwhat сomplасеnt viеw: sampiingеffесtsand mоlесular phylogеniеs.In both саsеs thе сritiсs aссеpt that tlrе fossil rесnеvеnts аrе nothing morе thаn сlrengеs сrf еnvironmеnt. If thеrеis a mаjor rеgrеssiсln(rеtrеаtof thе sеa),sh:rllowmаrinе organisms аpparеntlydisappеar from sесtions. This сould Ье rесordеd аs an еxtinсtion' but ir is mеrеIyа sеdinlеntаryаrtifaсt. Snrith (200t ,2007I poirrtеdout' howеvеf'that thе divеrsifiсationof lifе in thе sеa durirrgthе last 250 million yеars is proЬablv rеal bесаusеsеa lеvеls wеrе falling duгing this timе: thе risе in divеrsit1, is ntrt drivеn Ьy a гisе in sеa lеvеl.

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1 0 0 Pаleontologу апd the Historу of I,ifе Pеtегsand Footе (2001,2002) wеnt onе stеp furthеr, arguing that virtually all thе fossil rесoгd is сlosеly dеpеndеnton thе sеdimеntaryrесord. Supposеd rxtinсtions' divеrsifiсations,and otlrеr Ьiolсlgiсalpattеrns arе аl1 apparеntly drivеn Ьy thе volumе of pгеsеrvеdroсk. Thеsе authors found that thе divеrsity of lifе apparеntly matсhеs thе numЬеr оf namеd roсk formations in North Amеriсa. So, thеy arguеd, whеn lifе аppеаrs to Ье divеrsifying, it is simply bесausеthеrе is morе sеdiпrеntaryroсk and lrеnсеmore fossils.IWhеn a mass еxtinсtion is idеntifiеd' it is nothing morе than a loss of apprtlpriаtе roсks in whiсh to prеsегvеfossils. Thеsе viеws hаvе Ьееn sееn as pеrhaps rаthеr еХtrеmе (Bеnton 2003; Pеtеrs 2005). Thе сorrеlation of numbеrs of namеd formations and divегsityof lifе rеpoгtеd Ьy Pеtеrs and Footе (2001,2002) сould Ье rеvеrsеd:it is just аs likеly that whеn lifе is divеrsе аnd fossils aге aЬundirnt' gеologistsrесognizе and namе morе formations. In gеnеral' of сoursе, as wе always tеасh oLlr stu. dеnts, сorrеlatioп does not imply сausatiotl.Furthеr, assurningthat roсk volumе, or somе proхy for roсk volumе, is purе еrror in our undеrstandingof thе fossil rесord and should thеn bе applied as a сOrrесtion fасtor is hеavy handеd-maior Ьiologiсal еvеnts suсh as divеrsifiсatiсlnsand mass ехtinсtions arе rеmovеd at a strokе. As Pеtеrs (2005) pointеd out' thеге ls no rеa. son to rеjесt thе proposal that mаrinе roсk volumе and marinе divеrsity might vary in сonсеrt with a third faсtor, suсh as sеa-levеlсlrаngе.AЬundant marinе roсks аnd aЬundant marinе fossils might aсtually rеflесt high sеa lеvеls and aЬundant marinе lifе: in suсh a сasе' to dividе thе pеak in mаrinе divеrsity Ьy thе pеak in marinе roсk voluпе would еffесtivеly rеmovе that (truе) Ьiologiсal signal. Muсh morе work is rеquirеd to invеstigatеfurthеr why thе marinе roсk and fossil rесords arе с
а p p r o a с h е s :f o s s i I d а t t first fossil of a group). dаtеs tend to Ье too o| spеaking froпr thе mol molесular agе douЬlin г h е i гp o s i t i o n . o n h а l l а d е v а s t а t i n gе х p o s u r l Ьееn shown to rеst on D o г h е s еd е Ь а t е sj u е v е r Ь r i d g еt h е g a p Ь е t to Ье good) and thе pr Ье donе to soпlе ехtеn Novaсеk 1l992) rеа|i sourсеs of data on th( logеny. By fossils thеy in thе roсks. Сlaсiistiсs n е W а p p r o а с h е st o d r l phologiсal oг molесulz Norеll аnd Novaсеk сomparеd for ссrngгuе thе fossils or thе trееs сhinе, oг omnisсiеnсе f o s s i l s е q u е n с е se n d t l . gruеnt' thеn proЬaЬly h i s r o г yo f l i f е . L a с k o f i s w r o n g o r t h е t r е е sa l and thеy show good с< vасеk l 992; Bеnton ar сatе thаt all grоups е. rесord' that thеrе is no fossil rесords,аnd thl r r е е sp l O r t е da g а i t l s ts t

Conсlusion

Palеontolоgy is an aп tееnth сеnturiеs. Тo m happеnеd sinсе Ьеyon poгtеdwееkly in Sсiеп аnd thе faсt that (dеs

ing is strong еvidеnсе thе history of lifе. But thе history of li а n o t h е г .g r o u p A g i v l r n a r r a t i v еi s i m p o r t а t l t

Pаlaoпtrllogуапd tbе Нistсtу' of Lifе еp furthег,arguing that virtuаlly tе sеdimеntaryrесord. Supposеd giсal pattеrnsarе aIl apparеntly sе authors found tlrat thе divеr. of namеd roсk formations in аppеaгsto Ье divеrsifying, it is ".kand hеnсе morе fossils. Whеn morеthаn а loss of аppropriatе Lthеrехtrеmе (Bеnton 2003; Pе.mеdformationsand divеrsity of 2 ) с o u l d Ь е г е v е r s е di:t i s j u s t a s е aЬundant,gеologistsrесognizе urse' аs wе always tеaсlr our stuFurthеr'assumingthat roсk volге егror in our undегstandingof J as a сorrесtion faсtor is hеаvy i v е г s i f i с a r i o nasn d m a s s е х t i n с 0 5 ) p о i n t е dО u t ' t h е r е i s n o r е а ;k volumе and marinе divеrsity ;h as sеa-lеvеlсhаngе,AЬundant rightaсtually rеflесthigh sеa lеv;е' to dividе гhе pеаk in marinе rе would еffесtivеly rепrovе that s rеquirеd to invеstigatе fuгthеr orrеlatеd,Ьut thе tеrrеstrialroсk

02).

:hе informativеnеss оf thе fossil ЬatеsaЬout thе timing of origins plaсеthе oгigins of Меtаzoa (anrd nrodеrlr oгdеrs of Ьirds ar-rd oldеstгеpгеsеntativе fossils (е.g., Kumaг and Hеdgеs 1998; Wray е of molесular еstimatеsfor thе s ago' with most еstimatеsсlosеr l ago. Thе rangеof molесulаr еsplaсеntalmammals and modеrn with morе еstimatеsnеarеr 120 э, rеspесtivеly,trom around 600 t molесulаr datеs сould indiсate ta or Ьoth. Мany сonrmеntators l Kumаr 2004) hаvе arguеd that аnd thаt thе mоlесr-llardаtеs arе )9; Bromham and Неndy 2000; potеntiаl proЬlеms with Ьoth

approaсhеs: fossil с.latеsarе always to() young, of сoursе (onе nеvеr finds thе firstfossil of a gror.rp),Ьut not outragеously too young' whilе thе molесulаr datеstеnd tсl Ье too old, somеtiпlеsЬy a long way. Graur and Martirr (2004), spеakingfronr thе rl-rolесular sidе, prеsеnt a roЬust attaсk on thе еvidеnсеfor just molесuiirragе douЬlirrg notеd, whilе Неdgеs and Kuпrar (2004| dеfеnd thеirposition.orl balаrrсе,howеvеr, thе nrolесular lindings that sееnlеdlikе a dеr,astаting eХp()surеof thе frаiltiеs of thе fossil rесord in 1996 havе norv bееnshorvnto rеst on fаr wеаkег grouтld thаn was first assеrtеd. Do thеsе dеЬatеs just rеduсе to irssеrtiсlnand с()untеrassегtion?Сan wе еvеrЬridgеthе gap Ьеtwееnknowlеdgе of thе fossil rесord (whiсh is aссеptеd t o Ь е g o o d )а n d t h е p r o Ь l е m o f u n p r е s е r v e dl i f е o f t h е p a s t ? P е r h a p st h i s с a n bе donе to somе ехtеnt. ln a Ьrilliаnt ехamplе of latеral thinkrng, Norеll and Novaсеk (|992\ rеalizеd that еvolutiolristsuniquеlv had thrее indеpеndеnt sourсеsof dаta on thе history оf lifе: fossils, сladistiсs, aпd rnolесular phylogеny.By fossils thеy mеant thе stratigrаphiс сlrdеr of oссurrеt-tсе of fossils irrthе roсks. Сlaсiistiсsand nroiесular phylogеn1'rесOnstruсtiotrlrе rеlativеly nеWapproaсhеsto drаwing еvolшtiol-rary trееs' rvlrеtlrеron thе Ьasis of lrr
Сonсlusion Palеontologyis an аnсiеnt suЬjесt, dating Ьaсk tсl thе siхtееnтh or sеvеntееnthсеntttriеs.To п]any' it had its hеyday in Viсtorian timеs, and littlе has happеnеdsinсе Ьеyond thе disсovеriеs of nеw dilrosаurs and lronrinids rе. portеd wееklу l'nSсiепсе aг'd Nаtltrе' In a sеnsе,as I havе ilrgttеd, thаt is trr.tе, аnd thе faсt that (dеspitеtlrе сlain-rs)thеsе t-tеwdisсtlvеriеsaге rtrrеly slroсk. ing is stгоngеvidеrrсеthat tlrе fossil rесord tеlls us solnеthinЕ]truthfr.llirlrtlut tlrе histсtгyof Iifе. But thе histoгy of lifе is morе than just а nаrrativе of first onе fossil, thеn anothеr'group A givillg Wav to grсltrpB' and so On through to mankind. Thе narrativеis important for what it tеlls us aЬout thе аstonishin!]invеntivеnеss

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1 0 2 Pаlеoпtologу апd thе Нistorу of Lifе .$Иhiсh of lifе, its aЬility to еvolvе and do unprеdiсtаЬlеthings. Dеvonian oЬsеrvеrwould havе prеdiсtеd that thе multilimЬеd insесtsthat сrеpt round thе watеrsidе plants would onе day takе to tlrе air? \Whiсh Jurassiс oЬsеrvеr would havе guеssеdthat thе insесts shе saw flitting and danсing in tl-rеsunlight around thе muddy lеgs of thе dinosaцrs would еvolvе soсiality ilrrd thеrr drivе thеir Ьiodivеrsityand gloЬal Ьiomass t<> untold lеvеls?Сurrеt-ttЬiodivеrsity is highеr thаn it еvеr has Ьееn.!Иhеrе пlight lifе еvolvе nехt? Thеrе аrе intimаtions of miсroЬеs that livе in iсе and iп boiling Watеrs, and soпrе that livе pегhaps thrее kilomеtеrs down within thе roсks Ьеnеath thе sеa floor. Thеsе ехamplеs strain сrеdulity, but thеy havе happеned and arе happеning. Thеrе is morе to thе study of thе history of lifе, though, than mеrе doсumеntation of fossils. Fossils rеprеsеnt ехtinсt groups. Dinosаuгs сannot Ье prеdiсtеd from molесulеs, bшt thеy ехistеd arrd show us organisms tlrat did what no living animal doеs. Somе dinosаLlrswеrе 10 timеs thе nrass of thе lаrgеst living maпrrlals. Somе ptеrosaurs Ьad wingspans thrее or four гimеs thosе оf thе largеst Ьirds today. Somе ехtinсr arthropods wеrе largеr than any alivе today. Thеsе organisms arе all truly wondеrful, and thеy posе intеrеstingproЬlеms fсlr Ьiomесhaniсistsand physiologists. Divеrsifiсations and mаss ехtinсtions саn Ье prеdiсtеd (rеtrodiсtеd?)from studiеs of modеrn phylogеniеs,Ьut thе dеtails lravе always rеmainеd mystеrious. Palеontologists havе tlrе grеat plеаsurе of Ьеirrg aЬlе to dissесr suсh еvеnts in finе dеtаil, and as fossil-сollесtingtесhniquеs'thе prесisiorrof dating, and еnvironnrеntalanalytiсal tоols iпrprоvе, thе lеvеl of undеrsranding will inсrеasе. Spесiation сan Ье studiеd in thе laЬoratory and in long.tеrm studiеs in thе fiеld, Ьut thеrе is always a timе limit. Now' with improvеd сollесting and dating tесhniquеs,palеonrologiсal studiеs of spесiеsеvolution and spесiеssplitting сan Ье tiеd sеamlеsslyto thе prеsеntdаy, :rrrdwe arе Ьеginningto sее for thе first timе maсroеvolutiorrir.raсtion. Nеw finds сapturе thе hеadlinеs, Ьut nеw insights into Ьioгnесhaniсs, largе-sсаlееvеnts,and maсroеvolution arе еvеn morе imprеssivе.Tlrе study of thе history of litЪ has nеvеr Ьееn morе ехсiting than it is now. в|BLIoGRAPHY Bеnton,M. J. 1985.Маss ехrinсtiоnanlOngnоn-nrаrinе tеtrаpods. Nаturе3|6: 811-814. 1987.Progrеssаnd сompеtitionin llrirсroеvolutitл. Bhklgiсаl Rс,t,iсtlls 62-: 3 0 5 - 3 38 . 1995.Divеrsi{iсation аnd ехtinсtionin thе historyof |tfe.Sсieпсе268: 52-s8. 1997.Modеls {or thе divеrsifiсаtiono| \ifе.Тrепdsiп Есologу апd Еuс.llutioп|2: 490-495' |999' Еar|уоriginsof modеrnЬirdsand пrапrmals: Мolесulеsvs. mоrphоlogy.BlсlЕss.:1's 21: 1043-1051. 2003.Thе qualitvof thе fossilrесord.lп P. C.-. .}.Donoghuеаnd М. P. Sпrith,еds.,TеIliпgthе Еuоlutioпаrу-Тiпtе:МtэIесulаrСbсks апd t|lе Fсlssil Reссlrd,66-90. Boсa Raton,FL: СRС |)геss.

Bеntоn'N4.J.' and F. J B е n t o n 'М . J . , a n d D . l.ongman. 2О08.Iпtrodu Blaсkwеll. Bеntorr'М. l., аnd P. l

L|сrllсlgуаltd Еuol Bеntсln, М. J., anсl G. Palеontоlоgiсal kr Bеnt
Pаlеoпtologу аnd thе Historу of Life

:taЬlеthings.Whiсh Dеvoniаn oЬ. limЬеdinsесtsthat сrеpt round thе thе air? \Иhiсh Jurassiс oЬsеrvеr rw flitting and danсing in thе sunrrs would еvolvе soсiality and thеn to untold lеvеls?Сurrеnt Ьiodivеrnight lifе еvolvе nеxt? Thеrе аrе inLЬoiling Watеrs' and somе thаt livе roсks bеnеath thе sеa floor. Thеsе p p е n е da n d a r е h a p p е n i n g . y of lifе, though, than mеrе doсuinсt groups. Dinosaurs сannot Ье l and show us оrganisms that did LrrsWеrе 10 timеs thе mass of thе rad wingspansthrее or four timеs tinсt arthropоds wеrе largеr than r u | y w o n d е r f u l .a n d r h е y p o s е i n lphysiologists. n Ье prеdiсtеd(rеtrodiсtеd?)from ails havе always rеmainеd mystеriurе of Ьеing aЬlе to dissесt suсh g tесhniquеs'thе prесision of datlprovе' thе lеvеl of undеrstanding lry and in long-tеrmstudiеs in thе with improvеdсollесtingаnd dat;pесiеsеvolution and spесiеssplitry, and Wе arе Ьеginningto sее for nеw insights into Ьiomесhaniсs, ) еvеn morе imprеssivе.Thе study lхсiting than it is now.

n-marinеtеtrapods.Nаturе З16: :roеvolution'B iologiсаl Rеuiеtas 62: thе history of |i|e,Sсiеnсе 268: |lfe' Тrепds iп Есoklgу апd d mammals:Мolесulеs vs. tn P. С. J. Donoghuе аnd М. P. : МоIесulаr СIсlcks апd thе Fossil is.

Bеnton,M. J., and F. |. Ayalа. 2003. Dating thе trее of |ife.Sсiепсе30О: 1698_\70О. Bеnton,N,I.J., and D. A. T. Нarpеr. 1997. tsаsiсPаlеспtologу. Нarlow, Еssех' U.K.: l,ongmаn. 2008. Iпtrodl|сtioп to Pаlсobiсiogу апd thе Historу of Life, Oxford: Blaсkwеll. Bеnton' M. J., and P. N. Pеarson ' 2001 , Spесiation in thе fossil rесord. Тrепds iп F'сologу апd Еurllиtklп 16: 4О 5-41 1'. .W. Stоrrs. 1994. Tеsting thе quality of thе fossil rесord: Bеnton,М. J., and G. Pаlеontologiсаlknowlеdgе is improving. Geologу 22z |t|_1\4' Bеnttln,М.J., М. A. Wills, аnd R. Hitсhin. 2000. Quality of thе fossil rесord through ttmе.Nаturе 4ОЗ: 5З4_5З7. Brоmham, [-.D., and М. D. Hеndy. 2000. Сan fаst еarly ratеs rесonсilе molесular dаtеs tсl thе СamЬrian ехplosiоn? Proсееdiпgs сlf thе Roуаl Soсiеtу of Loпdoп, Sеriеs B 267: "l'041-|047 .

Сhееtham'A. H., and J. B. с.Jaсksоn. 1995. Proсеss {rom pattеrn:Tеsts for sеlесtiоnvеrsus random сhаngе in punсtuatеd Ьryozoan spесiation.In D. H. Еrwir"rand R' I,. Anstеy, еds.' Neи, Аp1lrоасhеs to Spеciаtkп iп thе Fossil Rессlrd,\84_207. Nеw York: СoluIтЬia Univеrsity Prеss. Соnway Мorris, s. 2003. Lifе's Solutioп: Iпеuitаblе Hиmапs iп а Loпеlу Uпiuеrse. СаmЬridgе: СаmЬridgе Univеrsity Prеss. Соopеr, A., аnd D. Pеnny. 1997. \4ass survival of Ьirds aсross thе СrеtaсеousMolесulаr еvidеnсе.Sсieпсe275: 1109-1'113. Tеrtiаrу Ьor-rndaтy: Darrvin, с. 1tls9' Оп thе Оrigiп of Spесles.London: John Мurray. Еastеal,S. 1999. iVlolесulаrеvidеnсеfor thе еarly divеrgеnсеof plaсеntal mammals. Bbl.ssays 21 :'l 0.52-10-58. Еldrеdgе'N., and S. J. Gould. 1972. PunсtuatеdеquiliЬria: An altеrnativеto phylеtiс grаdualism.In T..|. M. Sсhopf, еd.,МodеIs iп Pаleobiology, 82_115. San Franсisсo:Frееman, Сoopеr. Еrwin, D. Н., and R. L. Anstеy. 1995. Spесiation in thе fossil rесord. In D. H. Еrwin аnd R. I-. Anstеy, еds., Nси Аpрrсlасhеs fu Spесiаtiсlп iп tbе Fossil Rеcord' 11_28. Nеw York: Сolumbiа Univеrsitу Prеss. Fаrа, F].2002. Sеa lеvеl variations аnd thе quality of thе сontinеntal fossil rесord. ]сlttrпаIof the С}еologicаlSсlсiеtу, Lсlпdoп 159:489491'. Gould, S. .|. 1990.Is а nеw and gеnеral thеory of еvolution еmеrging?Pаleobiologу

6 : 1I 9 - 1 3 0 . Gould, S.J., and С. B. Сalloway. 1980. Сlаms and Ьraсhiopods-ships that pass in thе night. PаIеobiologу6: З8З-396. Graur, D.' and \й/.Martin. 2004' Rеading thе еntrails of сhiсkеns: Мolесulаr timеsсаlеs of еvolution and thе illusiоn of рrесision. Trепds iп Gепеtiсs 20: 80-86. Неdgеs'S. B., and S. Кumar.2004. Prесision of molесular timе еstimаtеs.Trеndsin Gепеtiсs 2О: 242-247. Hеwzulla, D., М. с. Boultеr, М. J. Bеnton, and J. M. Hallеy. 1999. Еvolutionary pattеrnsfrom mass originatiоns and mass ехtinсtions. Philosophiсаl Trапsасtioпsof thе fuцаl Soсiеtу,SеriеsB З54:46З-469. Kumar, S., аnd S. B. Hеdgеs' 1998. A molесulаr timеsсaiе{or vеrtеЬratееvolution. Nаtиrе 392 917_920. LaЬandеira'C. С., and J. J. Sеpkoski lr. 1993. Insесt divеrsity in thе fossil rесord. S с i е п с е2 6 1 : 3 1 0 - 3 1 5 Lаndе, R. 19B6. Thе dynamiсs of pеak shifts and thе pаttеrn of morphologiсal еvolution. Pаlеobiologу |2: З4З_3 54. Mахwеll' W. D., and М. J. Bеnton. 1990. Historiсal tеstsof thе absolutе сomplсtеnеssof thе fossil rесord of tеtrаpods.Pаlеobiologу 16:322-3З5. May' R. \4. 1994. Соnсеptual аspесts сlf thе quantifiсation of thе ехtеnt of Ьiologiсal divеrsity. l,hilсlsophiсаl Тrапsасtit-lпsсlf thе Roуаl Soсietу, Sеriеs B 345:13-2О.

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Pаleontologу апd the Historу of Life Мaynard Smith,J., аnd Е. Szаthmirу. 1995.Thе Маior Trапsitionsiп Еuolцtioп. Oxford:.W.H. FrееmanSpеktrurn. Niklas, K.J., B. Н. Tiffnеy,and A. H. Knoll. 1983.Pattеrnsin vasсularland plant divеrsifiсation . Nаturе3О3:6\4-616. Norеll' М. A., and М. J. Novасеk.|992. Thе tЪssiIrесordаnd еvoluriоn: Сomparing сladistiсand palеontologiсеvidеnсеfor vеrtеbratеhistory.Sсieпcе 255 1690-1.693. histoгyof mаrinе Pеtеrs,S. Е. 2005. Gеologiссonstrаints on thе maсroеvоlutionаry animаls.Proсeеdingsof thе Natioпаl Асаdemу of SсiеttсеsUSА 102: |2З26_1'23зI. in thе Phanеrozoiс: A rеintеrprеtation. Pеtеrs,S. Е., and М. Footе.2001.Biodivеrsity Pаlеobio logу'27: 5 83-6О1. 2002. Dеtеrminantsof ехtinсtionin thе fossilrесord.Nаtиre 416:420424. Sеpkоski,J.J.' Jr. 1'984.А kinеtiсmodеlof Phanеrozoiсtaхonomiсdivеrsity.III. Post-Palеozoiсfamiliеsаnd masseхtinсtions.Pаleobiologv\О: 246_267. |992'Phу|ogenеtiсand есologiсpаttеrnsin thе Phапеrozoiсhistoryof mаrinе Ьiodivеrsity.In N. Еldrеdgе,еd.,Sуstеmаtiсs,Еcologу,апd thе BiodiuеrsitуСrisеs,77-100. Nеw York: Сolumbia UnivеrsityPrеss. 1993.Tеn yеarsin thе librarу:How сhangеsin taхonomiсdataЬasеsaffесt pеrсеptionof maсroеvоlutionarypattеrn.Pаlеobiologу|9: 4З_5|. Thе douЬlеwеdgеrеvisitеd.In D. 1996.Сompеtitionin maсroеvolution: D. Н. еds', ЕuolutklпаrуPаlеobiologу, Н. Еrwin, and Lipps, J. Jablonski, 211-255.Сhiсаgo:Univеrsitvof СhiсagoPrеss. еvolutionof ordoviсiantrilobitеs.Nаtцrе Shеldon,P. R. 1987.Parаllеlgradualistiс 330:561-563. 1996.Plus ga сhаngе-A mоdеlfor stasisand еvolutionin diffеrеnt Pаlеoсlinшtologу,Pаlесlесologу127:209-227. Pаlеogесlgrаpllу, еnvironrnеnts. for hеtеrogеnеity of thе fossilrесord:Impliсations Smith,A. B.200 l. Largе-sсalе Phanеrozoiсbiodivеrsitystudiеs.PhilosophicаlTrапsасtiсlnsof tbе Roуаl Societу,SeriеsB 356: 1-|7. PrоЬlеmsаnd prospесts. 2007. Магinе divеrsitythroughthе Phаnеrоzoiс: lournаl of thе GeologiсаlSociеtу164:731_745. Sorhannus, U., Е.J. Fеnstеr'L. Н. Burсklе,and A. Нoffman' 1998.Сladogеnеtiс aпd anagеnеtiссhаngеsin thе morphologyof Rhizсlsolепiаprаеbеrgoпii Мцkhina. HistoricаlBiologу 1: 185-205 Stanlеy,S. М. 1975. A thеoryof еvolutionaЬоvеthе spесiеs|eуe|.Proсееdiпgsof thе Nаtioпаl Асаdemу of SсiеnсеsUSА 72: 646-650. 2007. Аn analysisof thе historyof marinеаnimаl divегsity.Pаlеobiolog,Меmoirs4. Pаlеobiology 33 (Suppl.):1-55. doсumеntation of spесiationin Сеnоzoiс Williamson'P. G. 1981.Palеontologiсаl mollusсsfroпrthе Turkana Basin. Nаture 29З: 4З744З. \йИrаy, G. A.2001. DatingЬranсhеson thеTrееof Lifе usingDNА. GeпomeBiсllogу 3:

t-/.

Wray, G. A.' G. s. Lеvinton,and L. H' Shapiro.1996.Мolесularеvidеnсеfor dееp PrесamЬriandivеrgеnсеsamongпlеtazoanpЬу|a.Sсiencе274: 568_573.

Adaptr

JosеphT

What Is Adaptа

Тlrе fеаturеs ()f org lifеstylеs. ln soпtе . Ьrown, mottlеd m( fusеlу shаdеd Ьrov that ссlmЬinе tO pе ing Ьird еggs hаv( s n a k е s ) ,l l o u t h s w ] Ьraе Ьеhind thе nt еmpty shеlls for е: fundaпrеntа1oЬsег how rlrеsеmatсhеs gists want to solvе Thе еаrliеst sсiе tеstеd with oЬsеr еmеrgеd through : wеrе сrеatеd Witl.l priatе f()r thеir ра Wеnt ехtinсt, lеtrv stanсеs. This thсo or ехtinсtion tlf v. loсations (е.g.,Тo n 6 n d е z I s l а n d :Е i s апd it sееmеd rеаs othеrs through tl that naturе сOuld Тhе tlrеorу of a thе ссlnviсtiorrthс intеrvеnеd throuр thе fеilturеs of Pl. and pеts Ьorе аm

,he Маjor Trапsitiсlпs iп Еuolutiсlп. 983. Pattеrnsin vasсulаr land plant Ъssil rесord aпd еvolutioп: dеnсе for vеrtеЬratеhistory. Sсiепсе maсгoеvolutionary history of marinе lеmу oi Sсiепсеs IJSА |О2: n tЬе Phanеrozoiс:А rеintегprеtаtion. е fossil rесord. Nаture 416 420424. anегozoiэtаxonomiс divеrsity. III. ns. Pаlеobiologу 10: 246-267. n s i n r h е P h l n е r o z o i сh i s t o r yo f уstemаtiсs,Ессllogу, апd thе olumЬia UnivеrsityPrеss. angеs in taxonomiс datа Ьasеs аffесt Pаleobiologу 19: 4З_5 1. Thе douЬlе rvеdgеrеvisitеd. In D. Js., Еuolutio паrу Pаl аl b iologу, Prеss. tion of ordoviсian triloЬitеs.Nаtиrе sis аnd еvolution in diffеrеnr ftologу, Pаleoесologу 127 : 2О9-227. .thе fossil rесord: Impliсаtions foг biсаl Trапsасtioпs of thе Roуаl anеrozoiс: ProЬlеms and prospесts. -745. lA. Hoffmаn' l998. Сlаdоgеnеtiс ' of Rhizosolепiа prаеbеrgoпii vе thе spесiеs|eve|.Pr
Adaptation JosеphTrаuisапd DаuidN. Rezniсk

What Is Adaptation? Thе fеarurеstlf orgzrnisпlsarе wondеrfully suitеd to thеir еnvironmеnts and lifеstylеs.In sonlе сasеs thе mаtсlr of fеaturе аnd еnvironmеnt is simplе: a browтr,mсlttlес]moth is сryptiс to its prеdators whеn it is rеsting on a diffusеly slradеd Ьг
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Adаptаtiсlп fеaturе of a plant or animal. But thеrе wеrе oЬvious limits to mallеaЬilityсhiсkеns саnnot bе Ьrеd to lаy two еggs pеr day evеry day of tlrеir livеs-and naturе sееmеdaЬlе to distingurshonly suЬstantialdiffеrепсеsamong spесiеs or stoсks (Provinе 1971; Rusе 1979)' Thеsе substantial diffеrеnсеssееmеd сapaЬlе of Ьеing produсеd only Ьy sеlесtivеЬrееdingof faгm stoсk (if naturе Was sorting among variеtiеs of donrеstiс goats introduсеd to an isl:rnd) or original сrеation (if naturе was sorting among spесiеs). This еxplanation of adaptiltion Ьесamе inсrеasingly сumЬеrsome аs morе and morе fossil organisms wеl.еdisсovеrеd.Foг onе thing, layеrs of roсk that inсludеd fossilizеd spесiеs did not inсludе fossilizеd matеrial from еxtant spесiеs;if naturе wеrе mеrеly filtеring spесiеs'whеrе Wаs thе еvidеnсе that еxtant spесiеs had еvеr сoехistеd with ехtinсt onеs? For anothеr' although many fossil organisms Ьorе limlе rеsепrblanсеto еxtant onеs (е.g.'dirrosaurs), othеrs sееmеdvеry similar to еxtant spесiеs(е.g.'fossil floundеrs).It was unсlеar why onе spесiеsshould havе gonе еxtinсt wlrilе anothеr with vегy simi. lar fеaturеsshould pеrsist. Thе sсiеntifiс rеvolution in thе studу of adаptation is thе idеa of natural sеlесtion' as suggеstеdЬy Сharlеs Darwin and Alfrеd Russеl wallaсе. Although both mеn offегеd thе idеa, it wаs Dагwin who artiсulatеd it пrorе сomplеtеly and intеgratеd it morе thoroughly into a largеr thеory of Ьiologiсal еvolution. As a rеsult, wе usе thе tеrm Dаrшiпiап еuolutiсlп to rеfеr to thе proсеss through whiсh adaptations еmеrgе'a proсеssalso саllеd еuolutioп bу паtиrаl selесtiotl or аdаptiue euolutiсlп. In Darwinian еvolution, natural sеlесtion, соuplеd with inhеritanсе of small trаit diffеrеnсеs'is thе аgеnt of adаptation. Natuгal sеlесtionis a statistiсal filtеring Proсеss; individuals with partiсular сharaсtеristiсs аrе morе likеly to survivе or produсе morе offspring than individuals with othеr сharaсtеristiсs.A morе formal dеfinition of natural sеlесtionis thе сausal аssoсiation of a fеaturе or trait with fitnеss. Bу fitпеss wе mеan thе numЬеr of offspring that an individual lеavеsЬеhind; individuals that diе without rеproduсing havе zеro fitnеss. The саusаl аssoсiаtioп of а feаture or trаit tuith fitness mеans' opеrationally, that a fеaturе or vаluе of а rrait is dirесtly rеsponsiЬlе for whеthеr an individuаl livеs or diеs or why somе irrdividuals lеavе morе offspring than othеrs. For еxamplе' many frogs brееd in tеmpоrary pсlnds thаt hold watеr for a Ьriеf pеriod and dry еvеry sеason.Thе tadpоlеs in thеsеponds must сoпrplеtе thеir dеvеlopmеnt into juvеnilе frogs Ьеforе thе pond driеs and thеy arе killеd. Tadpolеs with vеry slow ratеs of dеvеlopmеntdiе Ьесausеthеy сannot сomplеtе mеtamогphosisЬеforе thе pond driеs. Nаtural sеlесtiоnfiltеrs individuals with diffеrеnt ratеs of dеvеlopmеnt so that only thosе with morе rapid dеvеlopmеnt еmеrgе from thе pond. This filtеring would havе no lasting effесt if irrdividuals who dеvеlopеd rapidly wеrе not gеnеtiсally distinсt from thosе that dеvеloped slowly. Thе еffесtivеnеss of natural sеlесtion еmегgеs from thе hеritaЬlе naturе of trait variation; in thе nехt gеnеration thе gеnеtiс variаnts rеsponsiЬlеfor thе favoraЬlе trzritvaluеs will inсrеasе in rеlativе aЬundanсе. In tlrе frog ехaпrplе,

thе gеnеs rеsponsiЬlе fo thеy wеrе in thе prеviotr dеvеlopmеnt diеd with . quеnсy of thе favorеd gt lесtion to inсrеasе;morе avеragе thе nехt gеnеrаt

lесtion oссurs сonsistеnt Ьеing sеlесtеd сh:rngеsu tiotr aсts on тгаit vаriаt g r е a t е rг h е с u m r r l e t i v ес An аdaptation is any nеtiс rеsрonsе to а spесi plе' wе сall rаpir'1dеvеlo tеmporary ponds. Adap Ьесausе it еxplаins thе п v o k i n g p u r p t l s е f u ld е s i g mеnt for how nеw spе populаtions down divе1 Ьесomе so ехtеnsivеthа

Sеparlrtеspесiеs. Darwin's сritiсal argt сould irrdееd disringurs t r a v е l s h е h a d s е е n 't l п tions of thе samе plan сasеs thеsе diffеrеnсеsr Arсlripеlago; in othегs l i n t h е s a m е Ь i r t ls p е с i е madе rhеsе kinds of oЬ Hе saw all thеsе с1iffеr n а t u г с a s f i I t е r i l l gе х i s t individuаl diffеrеnсеs t

suЬstаntiаlсuпlulаtiv a m o n g p o p u l a t i o n s .Т } tion of whеthеr natural whethеr trait diffеrеnс and ultirnatеly whеtЬ i n t h е i r s е | е с t i r 'rее g i m a half.

Еvidеnсе for Adap

Biologists hirvе сonttn mеnt and havе ехtеnс lеvеl. Thеy havе alsс mаkе sсiеntifiс еxpla

АdаDtаtioп е obvious limits to mallеaЬilitydаy еvеry day of thеir livеs-and ;tantialdiffеrеnсеsamong spесiеs sе substantial diffеrеnсеs sееmеd Ьrееdingof farm stoсk (if naturе ;oatsintroduсеd to an island) or ,ngspесiеs). nсrеasinglyсumЬеrsomе as morе For onе thing' layеrs of roсk that : fossilizеd matеrial from еxrant :iеs,whеrе was thе еvidеnсе that inсt onсs? For anothеr, although :еto еxtantonеs (е.g.,dinosaurs), (е.g.,fossil floundеrs).It was unn с r w h i I еa n o t h е гw i t h v е r y s i m i laptationis thе idеa of natural sе.!7allaсе. Alfrеd Russеl Although ho аrtiсulatеd it morе сomplеtеly argеr thеory of Ьiologiсal еvolul еuolution to rеfеr to thе proсеss ;s also сallеd еuolиtioп bу паturаl эn, сouplеd with inhеritanсе of . t i o n .N a t u r а l s е l е с t i o ni s а s t a t i s rtiсulаr сharaсtеristiсsаrе morе than individuals with othеr сharrral sеlесtionis thе сausal аssoсifitпеss we mеan thе numЬеr of rdividualsthat diе without rеprotion of а feаture сlr trаit tuitb fitor valuе of a trait is dirесtly or diеs or why somе individuals rary ponds that hold watеr for a llеs in thеseponds must сomplеtе 'rе thе pоnd driеs and thеy arе :lopmеntdiе Ьесausеthеy сannot :iеs.Natural sеlесtion filtеrs indirt so that only thosе with morе :сt if individuals who dеvеlopеd hosе that dеvеlopеd slowly. Thе гom thе hеritablе naturе of trаit с variаnts rеsponsiЬlе for thе faaЬundanсе.In thе frog ехamplе,

thе gеnеsrеsponsiЬlе for morе rapid dеvеlopmеnt arе morе сommon than thеywеrе in thе prеvious gеnеrationЬесausеthе gеnеsrеsponsiЬlеfor slowеr dеvеlopmеntdiеd with thе tadpolеs that сarriеd thеm. Thе inсrеasе irr frеquеnсyof thе favсlrеdgеnеsсausеs thе avеragеvaluеs of thе traits r.rndеrsеlесtionto inсrеasе;morе сopiеs of gеnеsfor rapid dеvеlopmеntmеan that on .Whеn nаtural sеavеragеthе nеxt gеnеrаtionof tadpolеs will dеvеlop fastеr. lесtionoссurs сonsistеntlyovеr timе, thе avеragеvaluеs of thе traits that arе bеing sеlесtеdсhangе suЬstantiаlly.Thе longег and morе сonsistеntlу sеlес. tion aсts or-rtrait variаtion and thе morе gеnеtiс vaгiаtior-rin thе trait, thе grеatеrthе сumulativе сhangе in trait valuеs. An adaptation is any fеaturе of an organism that has еvtllvеd through gеnеtiсrеsponsеto a spесifiсесologiсal agеnt of natural sеlесtiсln.ln our ехаm. plе' wе сall rapid dеvеlopmеntratе an adaptation to thе risk of dеsiссаtionin tеmporaryponds. Adaptation is сеntral to Darwin's argumеnt for еvolution bесausеit ехplаins thе matсhеs Ьеtwееnfеaturеand еnvironmеnt withоut in. voking purposеful dеsign or spесial сrеation. It also providеs thе vital argumеnt for how nеw spесiеs arisе; whеn adaptivе еvolution takеs diffеrеnt populationsdown divеrgеntpaths, thе diffеrеnсеsЬеtwееnthosе populations Ьесomеso ехtеnsivеthat thеy no longеr сan intеrЬrееd,and еaсh Ьесomеs a sеparatеspес1еs. Darwin's сritiсal ergumеnt Was that naturе's filtеr, his natuгаl sеlесtion, сould indееd distinguish srтall diffеrеnсеs among individuals. Dr"rringhis trаvеls hе had sееn, timе and again, diffеrеnсеs in fеatuгеs аmong populations of thе sаmе plant or animаl spесiеs in diffеrеnt loсirtions. ln somс сasеsthеsе diffеrеnсеswеrе largе and dramatiс, as hе sаw in thе Galipagos Arсhipеlago; in сlthеrsthеy wеrе smallеr and morе suЬtlе, аs in diffеrеnсеs in thе samе Ьird spесiеsin diffеrеnt loсations in South Amеriсa. С)thеrshad madе thеsе kinds of oЬsеrvations, Ьut Darwin intеrprеtеd thеm diffеrеntly. Не saw all thеsе diffеrеnсеsas points along a сontinuum; rathеr than sееrng naturе as filtеring еxisting largе diffеrеnсеs,hе saw naturе аs filtеring small individual diffеrеnсеs that, ссluplеd with inhеritanсе and timе, produсеd suЬstantial сumulativе сhangеs in fеаturеs and suЬstarrtiаl divеrgеnсс a m o n g p о p u l a t i o n s .T h е t е s t i n g o f D a r w i n ' s a f ! ] u m е n t ,t h a t i s , t h е г е s o l u . tion of whеthеr natural sеlесtion сould Ье as powеrful as artifiсial sеiесti
Еvidеnсеfor Adaptation through Sеlесtion Biologists havе сontinuеd to dеsсriЬе thе matсh of tlrganism to еnvlronmеnt and hаvе ехtеndеd our knowlеdgе of that matсh to thе molесulаг l е v е l .T h е y h a v е a l s o u n с o v е r е d s t r i k i n g p a t t е r n s i n t h o s е m a t с h е s t h а t makе sсiеntifiс еxplanations tlthег than l)arwinian еvolution untеnilЬlе.

107

1 0 8 Adаptаtiotl And through oЬsегvаtionaland еxpеrimеntal str-rdiеs thеy lravе providеd thе answеrs to quеstionsthat Darwin and his pееrs сould сlnly pondеr. v A R | Е т |E s o F A D A P т A т I o N Naturе prеsеnts a widе variеty of adaptations. Сarnivorotts plаnts oссur in nutrl.еnt-poorsoil and usе thеir aЬility to сapturе and digеst insесtsto oЬtain thе nitrogеn that otlrеr plants aЬsorb through thеir roots. Сеrtаin fish and сrustaсeans that oссur in tеmporary ponds and floodplаins havе еggs that сan tolеratе соп-rplеtеdrving аnd сan rеst in thе soil until floodwatеrs Ьrеak thе animals' еstivation and induсе hаtсhing. Sеvеral spесiеsof fish livе in polar wаtегs that would fгееzеothеr irnimаls solid' rеlying on a spесializеd аntifrееzе protеin that tnhiЬits iсе-сrystal formation within thеir bodiеs (Hосhaсlrka arrd Somеro 2002). Adaptаrions also сomе in lеss dramаtiс vаriеtiеs.Damsеlfly spесiеs in thе genas Еnаllаgп1|l tь'at еnсountеr dragonfliеs as thеir primary prеdators havе diffеrеnt pattеrns of movеmеnt and ЬеЬavioг than spесiеs that oссur with fish as thе primary prеdator. Thе Ьеhaviсlrsthаt protесt against dragonfly prеdation fасilitatе fish prеdation аnd viсе vегsa' so thе Ьеhaviors arе wеll matсhеd to thе prеvailing prеdator (МсPееk 7995). Thе fungal pathogеn Сollеtotrichиm liпdemцthiапttm grows on two сlosеly rеlatеd spесiеsof Ьеan plants oftеrrfoul-rdin thе szrmеloсаtions, Phаseolus tlltlgаris and P' сocciпus, and produсеs thе samе lеsions аnd sсarrirrgon еaсh spесiеs. But thе fungal srrains on thе two htlst plants arе spесializеd at surmounting еaсh host plant's сhеmiсal dеfеnsеs,just аs diffеrеnt spесiеs of damsеlfliеs arе spесiаrlizеdat ovеrсoming diffеrеnt prеdators (Siсard еt аl' 2007). Populations of thе fish Fuпdulus heterсlclitцs from morе northегn li.rtitudеs havе diffегеnt forms оf the еnzymе laсtatе dеhydrogеnasеthan populations from morе southеrly latitr.rdеs. Thе struсturе and thе rеgulаtion of еxpгеssion of еaсh form is tunеd to thе prеvailing thеrmаl rеgimеs to produсе sirnilar rеaсtion rаtеs асross widеly diffегеnt tеmpеraturеs,whiсh allows thе spесiеs to thrivе aсross а widе rangе of thеrmal еnvironmеnts (Sсhultе

2001).

Bioсhеmiсal adaptаtions сan Ье partiсularly striking Ьесzrusеrhеy oftеn involvе thе produсtion of diffегеt-ltmolесulеs Ьy thе samе individual at diffеrеnt stаgеsof its lifе, suсh as thе еxprеssiоrrof hеmoglobin in frogs. Irr most vеrtеЬratеsthе hеmoglobin molесulе in thе Ьlood that сarriеs oxygеn to сеlls is lеss ablе to hold oxygеn undеr aсidiс сonditions. This propеrty еnlranсеs its funсtion; сеlls that arе starvеd fоr oхygеn arе aсidiс еnvironmеnts,and hеmogloЬin will rеadily gir,е up irs oxygеrr to thosе сеils. But many tadpolеs that livе in warm, shallow ponds havе a hеmogloЬin molесulе with thе rе. vеrsеpropеrty: it holds tightly to oхygеn undеr morе aсidiс сonditiorrs.Thеsе :rnimalslivе in vегy aсidiс watеrs, and this hеmogloЬin faсilitatеsthеir aЬility to еxtraсt oxygеn from thе Watеr еvеn whеn thеrе is littlе сlf it availaЬlе. Thеiг сеlls aге lеss aсidiс thаn thе \^ratеr' so oхYgеn is rеadily rеlеasеdwhеrе it is nееdеd.Upon mrtamorphosis thе adult frogs, whiсh Ьrеathеair' ехprеss

a diffеrеnt hеrnoglobin mogloЬin (Fеdеr and B Somе of thе nrost st parallеl adaptation. Сo is found in unrеlatеd ol ganisms display thе sa сasеs adaptations rеflес еxamplе, two unrеlаtес сonditions on two dii Amеriсa and Сh i rсlmоt; rathеr than trrеa, as do onе-twеntiеth of thе v adzrptivеsolution to thе A drirmatiс ехamplе h i s г o г i е so f g u p p i е s [ г r thаt is rеpеatеd in sеv. aсross thе island. Gup; maturе at latеr agеs aI tions' and upstrеam ft Thеsе diffеrеnсеs arе п guppiеssufiсг muсh hi1 and, in gеnеrirl,must с. from diffеrеnt drainag. downstrеam guppiеs ln Ьеtwееrrthе upstrеam a g a i n ( R е z r r i с ka n d T г а DЕMoNsтRAт|с

N{any biology tеxtЬook d u s t r i a l m е l a n i s mt o i l l 2005). As trее trunks oration of thе pеppеrе Ьlaсk
Аdаptаtioп rtal studiеsthеy havе providеd thе pееrsсould оnly pondеr.

:ions.Сarnivorous plants oссur in :apturеand digеstinsесtsto оbtain ough thеir rtlots. Сеrtain fish and ds and floodplains Ьavе еggs that in thе soil until floodwatеrs Ьreаk . Sеvеralspесiеsof fish livе in polar i, rеlying on a spесializеdantifrееzе ':ithinthеir Ьodiеs (Нoсhaсhka апd vаriеtiеs.Dаmsеlfly spесiеsin thе rfliеs as tlrеir prinrary prеdators Ьеhavior than spесiеs that oссur haviors that protесt against dragld viсе vеrsa' so thе Ьеhaviors arе or (MсPееk 1995I' Thе fungal m grows on two сlosеly rеlаtеd amе loсations, Phаseolиs uиlgаris ;ions and sсirrringon еaсh spесiеs. 1 t sa г е s p е с i а l i z е d. l t s u r l . I 1 о [ l n t i n g as diffеrеnt spесiеsof damsеlfliеs ' е d a t o r s( S i с a r d еt al. 2007). Popzs from morе northеrn latitudеs : dehydrogеnasеthan populations ,uге:rnd thе rеgulation of ехprеsg thеrmal rеgimеsto produсе simt tеmpеraturеs'whiсh allows thе f thеrmаl еnvironmеnts (Sсhultе rrly striking Ьесausеthеy oftеn ins Ьy thе sarrrеindividual at diffеr. n of hеmogloЬinin frogs. In most : Ьlood that сarriеsoхygеn to сеlls lnditions. This propеrty еnlranсеs n arе aсidiс еnvironmеnts,and hеto thosе сеlls. But mаny tadpolеs rеmogloЬirrmolесulе with thе rеtdеr morе aсidiс сonditions.Thеsе hеmogloЬinfaсilitatеsthеir аЬility 'hеn thеrе is littlе of it availaЬlе. ) oхygеn is геadilyrеlеasеdwhеrе r f r o g s ,w h i с h Ь r е . r t h еа l r , е x p r е s s

a diffеrеnthеmogloЬin gеnе whosе protеin Ьеhavеslikе most vеrtеЬratеhеnroglobirr(Fеdеr and Brrrggгеn 1992). Somе оf thе most striking patсеrns of adaptation involvе сonvеrgеnt or parallеladaptation.Сonvеrgеnt aс1aptationoссurs whеn thе samе adaptation parallеl adaptation oссurs whеn rеlatеd oris found in unrеlаtеdorganisп-rs; ganismsdisplay thе samе adaptatiоn through indеpеndеnt origins. In Ьoth сasеsadaptationsrеflесtrеpеataЬlеmatсhеs of оrg:rnismto еnvironmеnt.For еxamplе,two unrеlatеd frogs that livе undеr similaгly dеrrrandinghot dеsеrt сonditions on two diffеrеnt сontinеnts' Phуllсlmеdиsа sаuuаgii in South Amеriса aлd Сbirсlmаntisхеrаmpiliпа in South Afriсa еaсh eхсrеtе uriс aсid гathеrthan urеa' as do othеr adLrltfrogs; uriс aсid еxсrеtion rеqr-rirеsaЬout onе-twеntiеthof thе watеr rеquirеd for urеa ехсrеtion and rеprеsеnts an adaptivеsolution tо thе nееd for wаtеr сonsеrvation (Sсhmidt-Niеlsеn1990). A drаmatiс ехarтplе of parallеl adaptation is thе сontrast Ьеtwееn thе lifе historiеsof guppiеs from upstrеam and downstrеam loсations in Trinidad that is rеpеatеdin sеvеrаl drairrаgеsfrom onе mоuntаitl гangе to anothеr aсrossthе island. Guppiеs from upstrеam loсations Ьесomе rеproduсtivеly maturе at latеr agеs аnd largеr sizеs than guppiеs from downstrеаm loсaproduсе fеwеr, largеr ЬaЬiеs in еaсh Ьrood. tions, аlnd upstrеam fеr-rralеs Thеsе diffеrеnсеs arе matсhеd to thеir diffеrеnt еnvironmеnts; downstrеam guppiеssuffеr muсЬ highег prеdation ratеs, havе lowеr poprrlation dеnsities, and, in gеnеral,must сomplеtе thеir lifе сyсlе quiсkly or not аt all. Guppiеs from diffеrеnt drainagеs arе muсh lеss сlosеly rеlatеd than upstrеam and downstrеаmguppiеs in tlrе sanrе гivеr, rvhiсlr indiсatеs that thе distinсtions Ьеtwееnthе upstrеam arrd downstrеam populаtions havе еvolvеd timе and again (Rеzniсk and Trаvis 1996). DЕМoNsтRAт|oNs oF NAтURAL sЕLЕст|oN Мany Ьiology tехtЬooks still епrploy н. B. D. Kеttlеwеll's сlassiс study of in. dustrialmеlanism to illustratе thе powеr of natural sеlесtion (е.g.,Futuyma 2005). As trее trunks in Britain turnеd dark fror-nаir pollrrtion, thе сol. oration of thе pеppеrеd moth' Bistсlп bеtulаriа, сhangеd from mottlеd to Ьlaсk ovеr a largе arеa. Thе tехtЬooks usuаlly dеsсriЬеKеttlеwеll's oЬsеrvаtions of prеdation on tеthеrеd moths of diffеrеnt сolors on diffеrеnt Ьaсk_ grounds;prеdatогsfound it еasy to dеtесtnrottlеd moths сln dark trее trunks and Ьlaсk moths on liсhеn-ссllorес] trunks in unpollutеd forеsts.Although thе valuе of thе oЬsеrvationson tеtlrеrеdпroths has Ьееn quеstionеd Ьy сritiсs' thosе oЬsеrvations Wеге not thе сritiсirl еvidеnсе. Thе сonvinсing data еmеrgеd from Kеttlеwеll's mеtiсulous mark-аnd-rесapturе studiеs; hе markеd largе numЬегs of moths of diffеrеnt с
10')

1 1 0 Аdаptаtiсlп Thеrе arе thсlusandsof dеmсlnstrаtionsof rratural sеlесtion in aсtion. A widе variеty of есologiсal forсеs сrеаtе diffеrеnсеsin mortality ratеs or lеvеls of rеproduсtivе suссеssamong individuals with diffеrеnt trait valuеs or diffеrеnt сomЬinations of fеaturеs.Frсlm prеdators and pаthogеnstсl сold strеss and drought' frсrm studiеs of snаils in British fсlrеststo Darwin's finсhеs in thе Gal6pagos' thеrе is no room to quеstion thе rеality of natural sеlесtion (Hеrеford еt al. 2004). That natural sеlесtionoссurs is сlеar, Ьut сan it Ье a сlriving forсе of еvolution? Thеrе arе twtl quеstionsaЬout natural sеlесtionthаt arе сruсiаl to еstaЬlishing thе validity of Darwiniаn еvolution. First' сan sеlесtion among individuals Ье suffiсiеntly strong and сonsistеnt to mоld thе fеаtr.rrеs of organisms? Sесond, is thеrе еnough gеnеtiс vаriation f()Гtraits undеr sеlесtion to produсе suЬstantial сhangеs in thosе fеaturеs?Two linеs of еvidеnсе answеr Ьoth quеstioтlsin thе affirmativе. Thе first linе of еvidеnсесapitalizеson еnvirсlnmеntalаltеrationsmadе Ьy humans and thе rеsponsеsof organisrnsto thosе altеrаtions.Thе dеvеlopmеnt of antiЬiotiсs in thе 1940s and 19.!0s allowеd humans to сrеatе novеl еnvironmеnts for Ьaсtеrialpathogеns.To a Ьaсtеrium' an аntiЬiotiс is а toхin; to survivе,it must sеquеstеrthе ttlxin Ьеforеit pсlisonsthе сеll сlr dеnaturеit and rеndеr it harmlеss.This situаtion сrеаtеsа powerful sеlесtivеforсе fсlr altеrnativе bioсhеmiсal pathwаys within thе сеll; individuаls thаt сould dеlay or stymiе thе toxin's еffесt would dividе аnd rеproduсе morе oftеn than thosе that сould not. Slowly at first, Ьut at an aссеlеratingpaсе, spесiеsaftеr spесiеs of Ьaсtеrial pathоgеn еvolvеd fеatuгеsthat еnaЬlеd thеm to takе onе or anothеr path towаrd surviving in thе prеsеnсеof antiЬiotiсs.Although thе сеlls of Strеptсlссlсcиs|ook thе samе as thеy did in thе -l930s, thеir Ьiсlсhеmistry аnd сеllular mеtaЬolism arе vеry diffеrеnt (Dzidiс еt al.2008). SuЬstantial Ьioсhеmiсal еvolutitln in rеsptlnsеto mсrdеrnсhеmistгy is not сonfinеd to Ьасtеria. ovеr 1,000 spесiеsof insесts havе еvolvеd Ьioсhеmiсal rеsponsеsto insесtiсidе(Roush and МсKеnzie 1987) аnd wееdy plant spесiеs havе rapidly еvсllvеdrеsistаnсеto hеrЬiсidеs,еvеn glyphosatе'thе .,onсеin a сеntury'' hеrЬiсidе (Powlеs 2008). Many aquatiс organisms hаvе еvсllvеd adaptаtions to anthropogеniсаlly produсеd hеavy mеtals in wаtеr (Klеrks and \й/еis1987) ald many spесiеs of plants havе undеrgone ехtеnsivе Ьio. сhеmiсal and morphologiсal еvolution in rеsponsеto thе prеsеnсеof hеavy mеtals in thе soil produсеd Ьy thе еffесtsof rr-rining, lеаdеd gаsolinе,and еvеn thе zinс in galvаnizеd fеnсing (MaсNаir 7987I. In thе sесond linе of еvidеnсе,Ьiоlogists havе studiеd hundrеds tlf сasеs in whiсh individuals оf thе saпrеspесiеsfrom diffеrеnt ltlсations ехhiЬit rеаdily oЬsеrvаЬlе diffеrеnсеsin сoloratior.r,m
In thе most thoroug l u t i o n a r y t r а j е с t o г yo f thе most thoroughlу st lеss of strеam or mou havе fеwеr' largеr offs a t i v е s d o w n s t г е а m .Т r in upstrеam loсations than half as many offs nеwЬorns that аrе 50piеs.Thеrе arе a num in whiсh guppiеs arе opportunity Ьy introt t i o n s , i n е f f е с tr е p l i с a hаbitat (Rеzniсk еt al. aгy Path that in lеss thosе sееn in natural strеam еnvironmеnt, а d i f f е г е n с е sа m o n g i n moldеd nеw populаti еxpегimеnt that Darrд

How Do Wе Rесl

A l t h o u g h s t u d i е so f s t lution oссurs' thе full arе joinеd with pains ogy. of сoursе,thе [ not studiеd еvеry stril m o s t s с r u t i n i z е dс a s е T h е f е a t u r е st h а t d tiсularly strong ехalx sеquеnсе of fеaturе a rеduсtion of toеs, an thе molars. Biomесhz p а r t i с u l а г f е a t u r е s ;е l riods, and highеr mс vеgеtation likе grass. mаtе аnd thе еmеrgr lutionary pаthWay t family of grazing dеs risk from а vаriеty сl Suсh a rесonstruс еlongаtionof thе lim

aге dеvеlopmеntаlly vеlopmеntal mесhan

Аdаptаtiolt ns of naturаl sеlесtion in асtion. A iffегеnсеsin л-rortalit1, rаtеs oг lеvеls rls with ditlЪrеnttr:lit valuеs tlr difеdatorsand pathogеtlsto сolсi strеss ,ririslrforеsts to DilrwinЪ 6r"rсhеsirr ition thе rеality of natural sеlесti
9871.

; h a v еs r u d i с dh u r r . l r е dtsl i с a s е si n r diffеrеntlсlсationsехhiЬit rеadily lhologУ,lifе history, oг fеаturеsof rpаЬlеof intеrЬrеес1ing. Thеv havе and, through a variеty of ехpеriing iлdividuаIs ЬеtrvееnJoсatior.rs), ,n in thе diffеrеnt loсаtions is rе_ ; ( R е z n i с ka n d T r а v i s l 9 9 6 ; T r a v i s r r2 0 0 1 ) .

In thе most thorough studiеs Ьiologists havе rе-сrеatеdthе prеsumеd еvolutionarytrajесtory of thе diffеrеnсеs.Thе Trinidаdian guppiеs offег onе of thе most thoroughly studiеd еxarnplеs.Rесall that upstrеаm guppiеs, rеgardlеssof strеam or mountаin rangе, livе lсlngеr,maturе lаtеr and largеr, and havеfеwеr' largеr offspring at еaсh Ьor-rtof rеproduсtiorrthan thеiг сlosе rеl_ ativеsdownstrеam. Thе magnitudе of thеsе diffеrеnсеs is not trivial; fеmalеs in upstгеam loсations сar-rЬе morе than 20"Ь |argеr at mаturity, havе fеwеr than half as many offspring as downstrеam guppiеs, and produсе individual nеwЬornsthat arе 50_75% largеr than tЬosе produсеd Ьy downstrеam guppiеs' Thеге arе a numЬеr of upstrеam loсations aЬovе suЬstantial watеrfalls in whiсh guppiеs arе aЬsеnt.Jolrn Еndlеr аnd Dаvid Rеzniсk ехploitеd this opportunity by introduсing downstrеam guppiеs into somе of thеsе loсa. tions,in еffесtrеpliсаtingtlrе likеly сoursе of guppy сolonizаtion of upstrеam habitat(Rеzniсk et a|.1.997).Thе introduсеd guppiеs followеd an еvolutionary path thаt in lеss than siх yеars produсеd trait valuеs сomparaЬlе with thosе sееn in naturаl upstrеarn populаtions. Natural sеlесtiorrin thе upstrеаmеnvironпrеnt' aсting on thе gеnеtiс variation that was produсing small diffеrеnсеsamoпg individual downstrеam guppiеs trаnsplantеd upstrеam' moldеd nеw populations of upstrеam gtrppiеsirr vеry short ordеr. [t was thе ехpеrimеntthat Darwin would havе likеd to do.

How Dо.Wе RесonstruсtAdaptivе Еvolution? Although studiеs of sеlесtion and rеsponsе dеmonstratе that Darwintаn еvolution oссurs,thе full piсturе of adaptation еmеrgеswhеn stцdiеsof sеlесtion arе joinеd with painstaking work in gеrrеtiсs,dеvеlopmеnt, arrd pаlеontol. ogy. of сoursе' the piсturе is nеithеr сomplеtе nor pеrfесt; Ьiologists havе not studiеdеvеrv striking fеaturеof еvеry organism, and еvеn for somе of thе most sсrutinizеdсasеs' thеrе is still muсh to lеarn. Thе tеaturеsthat dеfinе thе modеrn еquids, horsеs and zеbras, offеr a partiсulаrly strong ехаmple (MасFaddеn 1992). Palеontology has rеvеаlеd thе sеquеnсеof fеaturе appеaranсе from thе еlongation of thе lowеr limЬs, thе rеduсtion of toеs, and thе еmеrgеnсеof hoovеs to thе inсrеasing hеight of thе rnolars.BionrесhаniсaIstudiеs havе pоinted to thе аdvаntagеsoffеrеd Ьy partiсularfеaturеs;еlongatеd limЬs faсilitatе rapid running for еxtеndеd pеriods, and highеr molars arе Ьепеfiсial for grazing touglr, siliсa-сontaining vеgеtationlikе grass. Plaсing thеsе сhangеs in thе сontеХt of a сhanging сli_ matе and thе еmеrgеnсеof savatrnasand plains, wе сan rесonstruсtthе еvolutionary pathwаy through whiсh small anсеstгal Ьrowsеrs produсеd а family of graztng dеsсеndants mtlldеd Ьy living irr opеn сOuntry аnd Ьеing at risk from a variеty оf largе prеdators. Suсh а гесonstruсtionpгеsumеstlrat thе transitionswе rесonstruсt,likе thе еlоngationof thе limЬ and thе rеduсtion in thе numЬеr of digits in thе foot, arе dеvеlоpmеntallypossiЬlе.That is, thе rесtlnstruсtionPrеsumеs that a dеvеlopmеntainrесhanisп-rftlr produсing suсh сhаngеs саn Ье dеsсriЬеd, and

111

1 1 2 Аdаptаtiсlп thаг thе gеnеtiс vаri:rtions in tlrе еlеrnеntsсhrсlr-rglr wlriсh thаr mесhаtlism сtltrld асt r'"'tluldhаvе Ьееn rеadily аvailaЬlе. Although Wе сanllor tеst thеsе prеsumptionsirr схtinсt spесiеs,W-ссilIl асquirе insights frtlm str-rdiсs of ехisting spссiеs. A4сlsttеrrеstrialvеrtеЬrаtеshavе fil,е digits сln thе fосlt at tlrе еnd of еaсh limb, Ьut thе position of thosе digits on thе foс.tt,thеir геlativеsizе, and еvеn thеir nr-шnЬеr с,.1nvаiv. Stuс1iсsсlf ftlсltand сligit dеvеltlpr-nеrrt il] traсtaЬlе ехpеrimеnt:rlаnimals likе salamandеrsаnd сhiсkеns havе shown that thе numЬсr, sizе, and position of digits arе dсtеrminеdЬ},molесtrlаrsigr-rals ехсharrgеd (ShtrЬin2002)' Rеlativеly Ь1,еmЬryoniс сеlls с]urirrgеaгl,vlimЬ dеvеlсritiсizс'tЬе gеnеrality rlf сonсlrrsionsаilсlut ada1rtatiсlndегivеd frсlпl а study on a snrall sсаrlе,suсh as thе сasе tlf industrial шеlаnisrn. Тсl a сritiс, thе rарid сlrаIrgеin thе frеquеnсr,of altегrrativеforms of :r singlе gеnе ftlг ссllсlratiсlnis lraгdly еvidеnсе thаt naturi-llsеlесtiсlt-l сan dгivе profound transformаtionsin orgаnismiс fе:lturеs-сl(lсharrgingсolсlr pаttеrnsin moths tеll rrs еntluglr tсl undеrstand h
quеstions has inspirеd ian еvolution' еvеn aп

сontrovеrsiеs in l

|s тHE RAW м READILY AVAII

At first glanсе thе ans' tаtion is rеаdily availа guppiеs offеrs сompt sцЬstantial adaptivе е е x с е p t i o n a l с а s е :h u п .

сellular сonсеntrаtio h i n d l i m Ь l е n g t ho f t r found apprесiaЬlе lеv viduals within a singl B u г t h е е х i s r е n с еo l that natural sеlесtiоn sharе dеvеlopmеntal valuеs to Ье inhеritеd to sеlесtion. In sеvеr liеs, swordtails, and п an еndoсrinе pathwа1 opmеnt (Kаllmаnl9t soсiаtion bеtwееn r.t Т h i s a s s o с i a t i o nп r е a largеr Ьody sizеs at п If slowеr maturation l solution; tlrе gеnеtiс maturation is not imr Thе kеy point геv Straint hold in thе lо suffiсiеntly long, wor thеsе traits? If sеlес m u t а t i o n s f а с i l i t a t еt

and rapid maturatio though it пay wеll h mау arisе, it is imp wоцld favor suсh а п T h е p o s s i Ь i l i t yo f . of adaptationsthat ;

еxamplе' most сasеS Ь е h a v е si n a p a r t i с u sumе a partiсular pО сoloration arе fаilrr

Аdаptаtiсlп ts througlr whiсh that mесhanism llе. Although Wе сannot tеst thеsе qLrirеinsightsfronl str-tdiеs сrtе-хisгgits on thе foot at thе еnd оf еaсh tе foot, tlrеirгеlirtivеsizе' and еvеn i digit dеvеloрmеntin traсtaЬlе ех:hiсkеnshar'сshсlwnthаt tlrе numlеd Ьy mtllесrrlаrsignаlsехсlrаngеd l t l p m е n t( S h u Ь i n2 o o 2 I . R е l a t i v е l y , :rnd pattеrning сlf thtlsе sigI-rals .еlopmеtrt.Dеlays in signalirrgr,l.ill аnd fifth digits, and if thеy do dе)еlаys irr signaiing, сouplеd u,ith tion of digits on tlrе foot. Thus alэpmеntirlpath that lеd to a hoof in -rrodеl through ц,lriсh сumulativе :ould havе trаnsfсlrmесlа fivе-toеd еvеlopmеntаIеlеmеnts havе Ьееrr -rdiеsof rеlativеhindlimЬ lеngth in . lеngth of tlrе hirldliпrЬ соmparеd i n d l i m Ь ss u Ь s t a n t i i r l livo n g е гt Ь a г ) d h i n d l i m Ь sa r е r a r е l y m o r е t h a n :latеdspесiеslikе thе Ьarking trее т LjnitеdStatеsсan hаvе sLlЬstаlr.hеsе diffеrеnсеsагisе from diffеrnd tlrс rаtе tlf linrЬ_Ьшdgrowth in tion for tlrе rеlativе lеrrgthof tЬе n singlе frсlg populаtions (Blouin rаtеriаl ftlr hirrdiimЬ еvоllrtion irr on to find in thе past lrnd, Ьy ехt h е ra n i m a l s . adaptation iп hoгsеs rvhtlsе prеrimеntalstudiеson Ьirds or frogs. y rvhеnWе attеmptto rесoпstruсt Ье fсlundin thе ftlssil rесorс]'It is l u s i o n sa Ь o u t а d a p t a t i o nd е г i v е d саsе of industrial mеlаnisnl. Tсl a altеrnativеftlrms of а singlе gеnе rral sеlесtionсan drivе prсlfound сhаrrgingсolсlrpаttеrllsin moths n пrolds fish musсlеs irrto еlесtriс ps foг сatсhing аnd digеsting irrn Ье aсlriеr,еdехpеrinrеrrtallyаt thе most importаnt еvolutionarv

quеstionshas inspirеd and sustainеdсonsidеraЬlесontrovеrsyаЬout Darwinian еvolution' еvеn among sсiеntistswho study it.

Сontrovеrsiеsin thе Study of Adaptation |s тHЕ RAW MAтЕRIAL FoR ADAPтAт|oN RЕADlLY AVAlLAвLЕ? At first glаnсе thе answеr to thе quеstion whеthеr thе rаw nrаtеriаl for аdаp. tation is rеadily availaЬlе would sееm oЬvious. Thе study оf thе transplantеd guppiеs offеrs сompеlling еvidеnсе that thе gеrrегiсvariation rеquirеd for suЬstantiаladaptivе еvolution wаs avаilaЬlе. This doеs not appеar to Ье an ехсеptionalсasе;hundrеds of studiеsof a variеty of сharaсtеrs,ranging from сеllular сonсеntrations of alсohol dеhydrogеnasе in fliеs and thе rеlativе hindlimЬ lеngth of fгogs to thе сolor of swallowtail Ьuttеrfly pupaе, havе found apprесiaЬlеlеvеls of gеnеtiсvariation for individual traits among indi. viduаlswithin a singlе population. But thе ехistеnсеof hеritaЬlе variation in singlе сhaгaсtегsdoеs not imply that natural sеlесtionсan mold fеatцrеsarЬitrarily. Diffеrеnt сharaсtеrs сan sharе dеvеlopmеr.rtal pathways that сausе partiсulаr сomЬinаtions of trait vаluеsto Ье inhеritеd togеthеrand thеrеЬy сonstrain thе immеdiatе rеsponsе to sеlесtion.In sеvеral spесiеsof pсlесiliid fish-thе fаmily of guppiеs, rnoliies,swordtails' arrd mosquito fish-thе proсеss of mаturation is govегnеd Ьy an еndoсrinеpathwаy that rеduсеsgrowth ratе as it aссеlеratеssехual dеvеlopmеnt (Kallman 1989). Thе gеnеtiсvariation in this pathway сrеatеsan assoсiation Ьеtwееn rapid nraturation ratе anс] sm:rll Ьody sizе at mаturity. This assoсiation mеans that thе rеsponsе to a sеlесtion pfеssurе that favors largеr Ьody sizеs at maturity will inеvitаЬly inсludе slowеr maturation rаtеs. If slowеr maturation ratеs arе dеtrimеntal for anу rеason' thеrе is no oЬvious sоlution; thе gеnеtiс variation for thе сomЬination of largе sizе and rapid maturation is not inrrnеdiаtеlyаvailaЬlе. Thе kеy point rеvolvеs around thе word immediаtе'lу; doеs suсЬ a сonstraint hold in thе long run? Ч/еrе wе to watсh suffiсiеr-rtlyсlosеly and wait suffiсiеntlylong, would Wе sеe mtltаtioпs in individual gеnеs that dissoсiаtе thеsеtraits? If sеlесtion aсtеd with suffiсiеnt сOnsistеnсy'would thеsе nеW mutations faсilitatе thе еvеntual еmеrgеnсе of thе сornЬinatiorr of largе sizе .Wе and rapid maturаtion? hаvе no simplе answеrs to thеsе quеstions; although it may wеll Ье that givеn еnough timе, a mutation of thе right kind may arisе, it is impossiЬlе to prеdiсt if thе есologiсal сirсumstanсеs that would favor suсЬ a mutation would still prеvаil whеn it finally arosе. Thе possiЬility of сonstrainеd gеnеtiсvariation provokеs a rесonsidеration of adaptations that aге Ьuilt on assoсi:rtionsЬеtwееn individLrаl trаits. For еxamplе,most сasеs of сryptiс сoloratiсln in animals work only if thе animal bеhavеsin a partiсular fashion, wlrеthеr it is to геmain motionlеss or to assumе а partiсulaг posturе or огiеntatioп.Мisrnatсhеs Ьеtwееn bеhаvior and сoloration arе failurеs. TЬе aгdеnt advoсatе of Darп,inian еvolution might

r1)

1 1 4 Аdаptаtioп arguе that natural sеlесtion hаs assеmЬlеdthе сomponеllts of suсh adapta. tions via mеtiсulous molding of individual fеi1turеsuntil thе Ьеst сomЬination еmеrgеd from all thе possiЬilitiеs.At thе othеr ехtrепlе оnе rтiglrt агguе that thе сonсегtеd inhеritanсе tlf thе сonrponеntsoffеrеd natural sеlесtiona limitеd rаngе of rarv mаtеrial frorr-rwlriсh only a fеw good matсhеs ttr сirсumstanсеswеrе pоssiЬlе. Ьy сonsidеring thе еvolution of аny Thе samе argumеnt саn Ье prov<>kеd putаtivе rldapt:rtionthat involr.еs пrultiplе сharaсtеrs, Ье it ;l Ьioсhеmiсаl patЬWay or a suitе of assoсiatеdЬеhavitlrs.Thе сontrovеrsy is not Whеthеr suсh fеаturеs rеprеsеnt adаptlltiсrns;thе сontrovсrsу is оvеr гhе еxtеnt tо whiсh adaptаtion is сonstrainеd Ьy thе naturе of thе аvailaЬlе raw matеrial. This is L.lеinglrpproасlrеd frоп-l sеvегal pеrspесtivеs, froпr ехапrinirrg thе naturе of nеW mutations for kеy сharaсtеrsto dissесtingthе аssoсietionsamong individual fеaturеsof an adaptation inttl thеir gеnеtiссontrсrland sЬarеd dе. vеlоpmеntal pаthwavs. ls ADAPтATIoN PЕRFЕст? Thе rrrarvеlousmatсhеs of orgаnisrrrto еnvirtlnmеnt offеr a strong tеп]ptation to сonсludе that adаptation is pеrfесt. Indееd, whеn сontеmplаting intriсatе adaptatiоns likе agе-spесifiсhеmogloЬin gеnе ехprеssion,thе amаzеd sсiеntist is rr
possiblе solution сontl Ь е s t i l l u s t r а t i o n so f t h i fеrеnt poptrlаtiоns of t есologiсal сhallеngе. сidеs; diffеrеnt populс Ь i o с h е m i с а lа n d p h y s (Мatsumurа and Voss еlесtriс fishеs сo-оptес o г g а n s ( B е n n е t t1 9 7 1 ) Thе othеr part о{ th ural sеlесti
organ and suЬsеquеnt tion. An еasiеr аnd bt not through thе rеtinа Thеrе is anothеr Wi

еrеd by еvolutionary fеaturеs of organisms pеrforrn a spесifiс funt that сapturе and foсus molесular signаls intt bееn сonsidеrеd ехam of thеsе сomplеx trait of Darwiniirn еvo|uti еvеry thеmе in thе stu

сAN DARWlNI ЕxPLA|N сoM

Darwin himsеlf appl dilеmma is thаt all sr boliс pathway likе tht pоsitе оf пrany indil propеrly intеgratеd fс Ьring so пlany things nаtural thеologian's z samе position tirkеn l tеnt thеsis offеrеd Ьy thе еyе or thе KrеЬs l lесtitln. Chаnging thс аnothеr (Aуala 2006

Аdаptаtion d thе сomp
пvironmеntoffеr а strong tеmptаt. Indееd,whеn сontеmplatirrgin;loЬingеnеехprеssion,thе аmazеd awеstruсk pоеt or thе inspiгеd this qr-rеstionas а tеstаЬlе idеa. Lwе might usе thе rcrm pеrfeсt; it аn orgаnism has adrrptivеsignifitisnr to еnvir
possiЬlеsolution сontingеnt on thе rаw matеriаl providеd Ьy mutation. Thе Ьеstillustratiоnsof this соntingеnсy oссur whеn diffеrеnt spесiеsor еvеn diffеrеntpopulatiсlns of thе sarrrеspесiеs rеsponс.lidiоsynсrаtiсally to tlrе sаmе есologiсalсhallеngе. This has oссurrеd in еvolution of rеsistanсе to pеstiсidеs; diffеrеnt population of thе two-spottеd spidег mitе еvolvеd diffеrеnt to сopе witЬ thе samе pеstiсidе Ьioсhепriсalаnd plrysiologiсal mесhar-rsims (Маtsr.rmuraanсl Voss 1964| and, on a largеr sсalе' whеrr diffеrеnt spесiеs of еlесtriс fishеs сo.optеd diffеrеnt musсlеs for transformation into thе еlесtriс organs(Bеnnеtt1971). Thе othеr part of thе аnswеr is morе suЬtlе: adaptatiоn is historiсal. Naturаl sеlесtion filtеrs variation in fеaturеs that arе thеrnsеlvеs produсts of prior еvolution' As a rеsult, thеrе is a signaturе of history on еvеry adapta_ tion, zrndhistor,vсаn gеnеratеfеaturеsand ссlrnЬinationsof fеaturеsthat arе proЬaЬly not wlrаt an intеlligent dеsignеr would produсе if thе orgаnism wеrе Ьеing dеsignеddе novo. For ехamplе, thе huпran еyе has a suЬstantial Ьlind spot саusеd Ьy thе thrеаding of Ьlood vеssеlsthrough thе rеtina. This inеffiсiеntstruсtllrеis a historiсal artifaсt of tlrе еyе'sorigin as a light-sеnsing еlаЬoration of thе rеtina as a Sсrееnfor imagе rеsoluorgan and suЬsес1uеnt tion. An еasiеr and Ьеttеr dеsign would wind thе Ьlood vеssеlsaround and not through thе rеtina. Thеrе is anothеr way in wЬlcЬ perfесtioп iп adaptation has Ьееn сonsidеrеd Ьy еvolutionary Ьiсrlogistsаnd сritiсs alikе. Сomplех adaptationsfеaturеsof orgarrismsth:1tarе ЬuiIt fгom maпy сharaсtеrs thаt сombinе tсl pеrform a spесifiсfunсtion' likе thе vеrtеЬratееyе, with suЬsеtsof сharaсtеrs that саpturеand foсus light, that dеtесt Ьrightnеssаnd сolor, and that rеsolvе molесulаr signurlsinto an aссuratе iпrаgе of rhе ехtеrnal world-havе long ..pеrfесtion.''Еxplaining thе еvolution Ьееnсonsidеrеdехamplеs of naturе's of thеsесomplеx traits has always Ьееn a сеntrаl сhallеngеfor thе сhampions of Dагwiniаn еvolution, anс] thе answеrs to th;rt сhallеngе illustratе nеarly еvеrythеmе in tl.rеstudy of adaptation. сAN DARW|N|AN ЕvoLUтloN ЕХPLA|N сoMPLЕx тRAlтs?

RЕALLY

Darwin himsеlf apprесiatеd thе сh;rllеngе posеd Ьy сomplех traits. Thе dilеrrrrnаis tlrаt all suсlr fеaturеs,whеthеr аn organ likе thе еyе оr а mеta. Ьoliс pathway likе thе Krеbs сyсlе usеd Ьy сеlls to produсе еnеrgy' arе a сompositе of many individual adaptations' all of whiсh n-rustЬе pгеsеnt and propеrly intе€ ] гatеdfor thе adaptatiоn to funсtiorr.Нow саl-lnatural sеlесtion Ьring sо many things togеthеrall at onсе and makе thеrn work propеrly? Thе natural thеologian'sanswеr in thе ninеtееnthсеntury was that it сannot' thе samеposition takеr-rЬy moс1еrnproponеnts of IntеlligеntDеsign' Thе сonsisnow, is tlrat thе ссlrnplеxity of tеnt thеsis offеrеd Ьy Darwin's сritiсs, thеn аr-rс1 thе еyе or thе KrеЬs сyсlе is too grеat to havе Ьееn Ьuilt by mutation аnd sеlесtion.Сhanging thе сolrrr of moths is onе thir-rg.Ьut Ьuilding аn е}.еis quitе anothеr(Ayala 2006).

, t.)

I16

Аdаptаtit'lп But is it? Dаrwin arguеd that ni]turalsеleсtiolrсoulс1produсе сtlrrrplехadaptations if thеy еvolvеd through a sеriеs of srтall stеps, еilсh of whiсh had sоmе аdaptivе advantagе ovег its prеdесеssor.Thе еvnaryPathway to thе Oсtoplls еyе has long sinсе Ьееn lost. ]Wеwould hаvе t-to bеttеr luсk traсir-rgthе pаthwirv to tlrе vеrtеЬrаtее1'е;nаtшrеnсlrv tlffеrs а largе group of organismstlrat all lravеwеll-dеvеlopеdеyеsехсеpt foг thosе living in vеry dаrk еnvir
hagfish). A sесond intеr ians, rеptilеs, аnd Ьirds t fish, and thе аdditiсlrra from Ьonеs assoсiatеdW Thеsе would Ье rеmark; tion drovе thе wholеsalс shapеs and сrеаting еntl

z0o7l .

But thе diffеrеnсеs rn Ьеst. Gill arсhеs arе a с( аs a Ьеllows. Fish usе t сavity. .Whеn a fish opеl oral сavity inсrеasеs,an' bеllows сontrасts and r( watеr through thе gill sl сеstors of all iawеd vеrl tеrЬorne pаrtiсlеs into t in thе oral саvity, whiс also funсtions as a rеsp wеll suppliеd with blo thеm, and thе thin tissu from thе watеr into thе dеrivеd from thе gill a gгasp and proсеss foоd е n h a n с е st h е t r а n s m i s s on thе outеr surfaсе of 1

gion of our skulls' Нow сan suсh divеrs Ьratеs, Ье еvolutionaril fish arе pаrt Of a rеpеа musсlеs that opеn arrd that ехpand and сontra arсhеshavе thе funсrio grasping and grinding t h е t r a r l s f o r m a t i o nf г o so dramatiс as to sее

сhangеs. Thе trаnsformation ] is lеss dramаtiс than it spесiеs.Thе fossil rесo isms that rеprеsеnta tl thе rеptilеs tl-ratаppес сompositе of sеvеn Ьol skull was formеd by t Ьonе on thе skull (Figr dеntary, and artiсula

Аdаptаtion есtion сould produсе сonrplех adap;rnallstеps,еасh t>fwhiсh hаd sсllr.rе rе еvolutionof thе еyе сould only Ье ]quеnсесlf rhеsеsmtrll сhаnges, аlrd t doеs rеquirеsan undеrstandingof Dереw2004)' To thе modегn еvrllu. .hесtlrrtingеrrt and lristoriсаl naturеs аfgumеntsft,г IntеlligеntDеsign' еyе Ьy pointing ollt thе divеrsity сlf - . i е so f g а s t r o p o d s( s n a i l s 'm u s s е l s , angе from сlustеrsоf сеlls in somе ht аnd dаrk to thе sоpЬistiсаtеd, n g е o f p h o r o ь е n s i t i voеr g l r n sс l i i n argued Ьy analog1',assегtinЕ]thаt rgans in gаstгop()dsillustratеs thе tor to dеsсеndanttо Ьuild thе most еyе, rvith a сompаrrаЬlеpossiЬiliгy .gumеntsrnall сhаrrgеsagainst thс. аn aссumulаtе ir-rtoa rеmarkаrЬlе 3rеaгknowlеdgеof aninrzrldivеrsity nvinсе thе сritiсs and, in faсt' doеs rrаlysis.Thе spесiеs irrvсllvеdin tlrе nothеrfor skеptiсaItastеs;thе fossil е nrtllесulаrdаtа sr-Iggеst thаt it hаs эf thеm shaгеd a сommoп anсеstor l thе idеa сlf еl.oltrtitln). Thе еvolug sinсe Ьееnlost. !Ие would havе no 'Ьrаtееl.е;nаttlrе nсlu,offегs a laгgе iopеdеyеsехсеpt1Ъгthosе living in ' sессlndariiyеvolvесlrеduсed еyеs. iinrplе to сornplех с.yеsoссurrеd in 'vеr400 million yеarsi1go. lluti
hagfish).A sесond infеrеnсе is that thе singlе middlе-еar ossiсlе of amphiЬians' геptilеs,аnd Ьirds rvas dеrir,еdtrom an еlеmеntof thе jaw suspеnsionof fish, and thе additional twtl middlе-еar ossiсlеs of mammals wеrе dеrivеd fronrЬonеsаssoсiаtеdwith thе |aw joint of tЬеir rеptilian anсеstors(F-igurеl )' Тhеsеwould Ье rеmarkaЬlе еvolцtionary еvеntsin whiсh mutation and sеlесtion drovе thе wlrolеsalеtransformation of сharaсtеrs' molding еntirеly nеw shapеsand сrеating еntirеly nеw funсtions (!7akе 1979; Radinsky 1987; Luo

2007\.

But thе diffеrеnсеs in funсtion rrrakе sцсh a progrеssion sееm fаnсiful at Ьеst.Gill aгсhеsarе а сompositе of Ьonеs, musсlеs, and nеrvеs that funсtion as a Ьеllows. Fish usе thеm to еxpand and сontraсt thе volumе of thе oral .!7hеn саvity. a fish opеns its mouth, thе Ьеllows еxpands, thе volumе of thе oral саvity inсrеasеs,and watег is drawn irr. !7hеn a fish сloses its rrrouth,thе bеllowsсontraсts and rеduсеsthе volumе of thе oral сavity as thе fish ехpеls Wаtеrthrough tlrе gill slits. ln living iawlеss fishеs(and prеsumaЬly in thе аnсеstorsof all jawеd vеrtеЬratеs),this pump is a fееding dеviсе' drаwing watеrЬornеpartiсlеsinto thе mouth that adhеrе to a stiсky suЬstanсеproduсеd in thе oral сavity, whiсh is thеn сonvеyеd to thе gut. Thе еntirе apparatus also funсtions аs a rеspiratory orgаn. Thе tissuеsthat linе thе gill aгсhеs arе wеll suppliеd with Ьlood; thе pump passеs frеsh, oxygеnаtеd watеr ovеr thеm,and thе tlrin tissцеstlrаt linе thе arсlrеsallоw oхygеn to Ье trаrrsportеd from thе watеr into thе Ьlood vеssеls.By сontrast, thе struсturеssupposеdly dеrivеd froпl thе gill аrсhеs lravе mrrrе сiгсumsсriЬеd funсtions. Thе jaws grasp and proсеss food. Thе first rniddlе-еarossiсlе in tеrrеstrialvеrtеЬratеs еnhanсеsthе transmission of thе еnеrgy in sound wavеs fronr thе еardrum, on thе outеr surfaсеof thе Ьody, to thе innеr еar, whiсh is in thе tеmporal rеgionof our skulls. L{ow сan suсh divеrsе struсturеs'not all of whiсh arе prеsеnt in all vеrtеЬratеs,Ье еvolutionarily linkеd to ol1еanothеr? Thе iaws in thе еaгly jawеd fish arе pаrt of a rеpеatеd sеriеs of Ьonеs that inсludеs thе gill arсhеs. Thе rnusсlеsthat opеn and сlosе thе jaws funсtion in a similar fashitln to thosе that ехpand and сontraсt thе gill arсhеs.In somе living spесiеsof fish, thе gill arсhеshavе thе funсtiollal еquivalеlrtof tееth and funсtion as do our jaws Ьy grаspingand grinding food. Givеrr thе pattеrns of musсlе аnd innеrvаrion, thе transformationfrom gill arсh tO jaW suggеstеdЬy thе fossil rесord is not so dramаtiс as to sееm an unlikеly сurrrulativееffесt of small, attain:rЬlе сhangеs. Thе transformation from jаw support in rеptilеsto еаr ossiсiе in maпrп.rals is iеss dramatiс than it might appеаr from соmparisorrsof only thе ехisting spесiеs.Тhе fossil rесord offеrs striking pattеrns of сlrаngе aсross thе organisms that rеprеsеnta transition Ьеtwееn rеptilеs and mammals (Figurе 1). In thе rеptilеs that appеar to Ье anсеstrаl to пrammals' tlrе lowеr jаw wаs a сompositеof sеvеn Ьonеs and thе artiсulation Ьеtwееnthе lowеr jaw and thе skull was formеd by thе artiсular bonе on thе lowеr jaw and thе quаdrаtе Ьonеon thе skull (Figurе 1A). In mammals thе lowеr jaw is a singlе bоnе, thе dеntary, arrd аrtiсulation of thе jаи. tlsеs thе dеntary Ьonе itsеlf аnd thе

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Figr-rrе1. This figurе, modifiеd from Luo 2007, illustratеs thе еvolution tlf thе manrmаlian jaw, сlегivесlfrom :r sеriеs of ftlssils in thе synаpsid linеagе (thе linеagе irl wЪiсh mаmm:rls сmеrgсd) аnd froп.l thе еmЬryсlniс dеvеltlpmеnt of tЬе living maЬrтals. Thе сlrawings on tl-rсlеft (A-D) rергсsеnt thс l
sqrramosal Ьonе on thе sids (thе sсiеntifiс tеrm jaw hingеs that сonsist thе lowеr jaw and thе q 1B_Е). This dual artiсu fеaturеs of thе skеlеton, rеptilеs and mammals. I and squamosal Ьonеs fil rеplaсеd thе artiсular ar onсе thе artiсular an of jaw and skull, thеy v fossils аnd from thе еml mals indiсatеs that thе and oriеntation' and с

(С) Brаsilith еriиm rep Triassiс through thе latе Pаchуgеnеlus (B) but rеt (D) Sinocoпсldon was ' from thе еarly Jurassiс,tl though thе individualЬo GI (Lеft) Мorgапuсoс late Triassiс thrоugh thе a 8 r е a t l yr е d u с е dp а r t i с To thе right of еaсh ol thаt thе stapеdialproсеs proсеssаrtiсulatеswith t ( Е ) ( R i g h t ) T h i si s a v с Мorgапucodoz, illustrаt sеriеsof Ьonеs inсluding bonеs havе a diffеrеntеn animals and thеy сan аls есtotympaniсis a ring o1 Ьеtwееn thе outsidе wor (F) Thеsе arе adult an О rnitb orhупchus. |n tЬe mеdial surfaсеоf thе lov есtotympaniс,mallеus'а сonfiguration sееn in thе (G) Thе lowеr drawin adult jaw of Yапсlсoпod Thе сondition of thе Ме duсk-Ьillеd platypus. (H) Thе lowеr drаwin oPossum' Мoпсl delph us еmЬryoniс jаw is vеry sr Yаnoсonсldoz, with thе thе lowеr jaw, whilе thе Месkеl еlеmеntsЬеingс

Аdаptаtioп squаmosalЬonе on thе skull. Somе of thе advаnсеd nonmammalian Synapsids (thе sсiеntifiс tеrm for thе ехtinсt group of mammal-likе rеptilеs) havе jaw hingеsthat сonsist of a сomЬination of thе dеntary and thе artiсular on thе lowеr jaw and thе quadratе and thе squamosal on thе uppеr jaw (Figurе 1B-Е). This dual artiсulаtion of thе jaw, in сomЬination with many othеr fеaturеsof thе skеlеton' indiсatеsthat thеsеanimals formеd a Ьridgе Ьеtwееn rеptilеsand mammals. In thе сasе of thе jaw joint, it appеars that thе dеntary and squamosalЬоnеs first wеrе inсludеd in thе jaw joint and thеn сomplеtеly rеplaсеdthе artiсular and quadratе Ьonеs as thе jaw joint. onсе thе artiсular and quadrаtе Ьonеs wеrе rеdundant in thе artiсulation of jaw and skull, thеy wеrе availaЬlе for othеr purposеs. Thе еvidеnсе from fossilsand from thе еmЬryoniс dеvеlopmеnt of thе most anсiеnt living mammals indiсatеs that thеsе Ьonеs Ьесamе rеduсеd in sizе' altеrеd in position and oriеntation, and сonvеrtеd into thе middlе-еar ossiсlеs, thе artiсular

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lustrаtеsthе еvolutiсln of thе n thе synаpsid lirrеagе(thе linеаgе in Liс dеvеltlpmеnt
(С) Brаsilithеrium rеptеsentsa third linеagеof Synapsids' found from thе latе Triassiсthroughthе latе Сrеtaсеous'that had thе samеdual artiсulationas (B) Ьut rеtainеda quadratojugai. Pасhуgеnelиs (D\ Sinoсoпсldonwas a mеmЬеr of a fourth Synapsid linеagе,known only from thе еarly Jurassiс,tЬat had a dual artiсulation likе thаt of Pаnуgeпеluseven thoughthе individual Ьonеshаd diffеrеntsizеsаnd shapеsthan in Pапуgеnelus. (Е\ (Lеft) Мorgаnucodoп rеPrеsеntsa fifth Synapsid linеagе,known from thе latеTгiassiсthroughthе mid-Jurassiс,that also had a duаl artiсulation,Ьut with ..inсus''and no jugаl. a grеatlyrеduсеdpartiсipationof thе ..inсus.''Notе To thе right сlf еaсh of thеsеfigurеsis a dеtailеddiagramof thе thatthе stapеdialproсеssis prеsеntin (C) and (Е) Ьut aЬsеntin thе othеrs.This proсеssartiсulatеswith thе stapеs'whiсh is thе third middlе еar ossiсlе. (BI вigha TЬis is a vеntraland latеralviеw of thе lowеr jaw of ..Mесkеl'sеlеmеnt,''whiсh is assосiatеdwith a Мorgапuсodoz,illustrаting sеriеsof Ьonеsinсludingthе есtotympaniс,thе mallеus,and thе inсus.Thеsе Ьonеshavе a diffеrеnt еmЬryoniс origin from thе othеr jawЬonеs in living animalsand thеy сan also Ье сlеarlyrесognizеdin somе fossils.Thе есtotympaniсis a ring of Ьonе that suppqrtsthе еardrum,whiсh is thе intеrfaсе Ьеtwееnthе outsidеworld аnd thе middlе еar ossiсlеs. (F)Thеsearе adult and еmЬryсlniсjaws of thе duсk.billеdplatypus'gеnus ornithorhупсhus.Inthе еmЬryo,thе Месkеl еlеmеntsarе attaсhеdto thе mеdialsurfaсеof thе lowеr jaw' as in Мorganuсodon.Latеr in dеvеlopmеntthе malleus,аnd inсus sеparаtеfrom thе lowеr jaw and produсеthе eсtotympaniс, сonfigurаtionsееnin thе middlе еar of thе аdult. (G) Thе lowеr drawing is a vеntralviеw, thе upPеr onе a mеdial viеw of thе adultjaw of Yапoсoпodon,an еаrly mammal that datеsto thе еarly Сrеtaсеous. aге similar to thosесlf an еmbryonlс Thе сonditionof thе Месkеl еlеmеrrts duсk-billеdplatypus. (H) Thе lowеr drаwing is thе mеdial viеw of thе еmЬryсlniсlowеr jaw of thе opossum'Мсlпodelphus,whilе thе uppеr drawing is thе adult jaw. Тhе emЬryоniсjaw is vеry similаr to thе adult jаw сlf Мorgапuсodon and Yапoсoпodoп,with thе Месkеl еlеmеntsЬеingattaсhеdto thе mеdiаl surfaсеof thеlowеr jaw, whilе thе adult сondition is typiсal of living mammals' with thе МесkеlеlеmеntsЬеingсomplеtеlydеtaсhеdfrom thе lowеr jaw.

119

1 2 0 АdаptаtЙlп into what is now сallеd thе rтallеus and thе quadratе into what is rrow сallеd thе inсus. Thе drivеr for this transformation would havе Ьееn natural sеlесtiсln'sfavoring еnhanсеdaЬility to dеtесtviЬrations. Rеsеarсhsuggеststhat thе jaw in thеsе transitionai animals transmittеd viЬrations from thе ground to thе mid. dlе еar, as it doеs in somе modеrn snakеs-think of a small, nсlсturnalanimal that piсkеd up viЬrations Ьy touсhing its jaw to thе ground and transmitting viЬrations from thе jaw to thе stapеs.Thеsе viЬrations would havе travеlеd through thе artiсular (mallеus) and quadratе (inсus) Ьonеs to thе stapеs.In two linеagеs of nonmammalian Synapsids, nеithеr of whiсh is anсеstral ttl mammals, thе inсus has an outgrowth сallеd a stapеdial proсеss' whiсh is a lеvеr arm that transmits thе forсе of thе sound wavеs from thе inсus to thе stapеs. Its prеsеnсе in thеsе two linеagеs stlggеststhat Ьoth of thеm wеrе еvolving an еnhanсеd саpaсity to transmit sound from thе jaw to thе stapеs and thеn to thе innеr еar. Thе arrangеmеnt of btlnеs in thе linеagе that inсludеs mamrnals is diffеrеnt than in thеsе othеr linеagеs Ьut doеs inсludе аn inсus with a stapеdial proсеss.Tlrе final stagеof сoursе is thе sеparationof thе ossiсIеsfrom thе jaw itsеlf. \й/hеnthе ossiсlеs Ьесamе sеparatеdfrom thе jaw' thеy сould transmit sound viЬгations еffiсiеntly from thе еaгdrum to thе middlе еar. Thе сomplеtе fossil rесord rеvеаls that, rathеr than thеrе Ьеing a dirесt transformation from the primitivе synapsid ссlndition to thе mammal сondition, thеrе was a divеrsity of arrangеmеnts сlf Ьоnеs in thе jaw-еar rеgion and a divеrsity of rеarrangеmеntsovеr timе. Thе anatomy оf living rеptilеs аnd mammals rеprеsеnts two еndpoints of а transformation that followеd divеrsе paths in Ьеtwееn,with most of thе variants having gonе ехtlnсt. Although thе fossils Suggеstthе progrеssionof fеaturеsin this transformation, dеvеlopmеntal Ьiology offеrs us twсl important additional lirrеs of еvidеnсе. First, whеn thе ossiсlеsfirst аppеar in mammalian еmЬryсls,thеy arе part of thе jaw assеmЬly.During dеvеlopmеnt'thеy sеparatеand f
m u s с l е s a s s o с i а t е dw i г dеrivеd from what is nеrvеs that sеrvе thеsе nеrvеs. All thеsе oЬsеrvation а r с h е sa n d t h а t t h е m l mutation irnd sеlесtion ponеnts. But hоw аnd \|977) onсс dеsсriЬе nееring; a tinkеr usеs v tions, whilе an еnginе that adaptаtion is a hrs s t г u с t u r е sf o r n е w f t l n (еffiсiеnt feеding) and fl into largеr, morе aсtiv tant funсtion of thе ph a n a s s o с i а r i o nw i t h f с . pharyngеal pump hav сlosе thе jаws, so thеy funсtion. Although thе transit dеrstand, thе assoсiatt tratе.Stiсk your fillgег will sее thаt thе jaw jо you сan fееl thе joint r

v е r t е Ь r а t е s .i n с | u d i n g: арpеаг гtlpiсk up viЬг and thеn to transmit th snakеs and small mamr t i o n s a r е n o с t u r n а |, r n е m е n г so f t h е j а w s t o l l a r g е l ye с o n s е q u е n с thе prior rоlе thаt thе j vironmеnt to thе innеr

Ехаrпple 2: FIorаI еul our sесond ехamplе, v nеtiс analysеs сontribu t a t i O n s( S с h е m s k еа n d wе foсus on shаpе and еrs fсlr thеir Ьеauty аn< rеproduсtivе struсturе pollеn (thе malе gamе malе gamеtе). Thе llowеrs that insp animal pollinаtors likr

Аdаptаtion hе quadratеinto what is now сallеd rld hаvе Ьееn naturаl sеleсtion,sfa. ns. Rеsеarсhsuggеststhat thе jaw in rаtionsfrom thе ground to thе mid-think of a small, noсturnal animal j а w t o t h е g г o u n de n d r г e n s m i г t i n g rеsеviЬratiorrswould havе trаvеlеd lratе (inсus)Ьonеs ttl thе stapеs.In Js, nеithеr of whiсh is anсеstral to Lllеda stapеdialproсеss,whiсh is a sound-лavеsfrom thе inсus to thе s suggеststhat bсlth оf thеm wеrе it sound from thе jaw to thе srapеs э that inсludеsmammals is diffеrеnt ludе аn inсus with a stapеdial proation of thе ossiсlеsfrom thе jaw itfrom thе jaw, thеy сould transmit drum to thе middlе еar. Thе сomln thеre Ьеing a dirесt transformа)n to thе mammal сondition, thеrе n thе jaw.еarrеgion and a divеrsity ny of living rеptilеs and mammals Ltionthat followеd divеrsе paths in ] gonе еxtinсt. ;sionof fеаturеsin this transformal important additionаl linеs of еvir in mammaliаn еrтЬryos,thеy arе nеnt'thеy sеparateand form thе fае 1F_H). \Whilеthе notion that an еvolutionaryhistory has Ьееn dis. :h dеvеlopmеnt offеrs a сluе to an lеaЬlеin thе fossils. сlеs havе a сritiсal rеlationship to thеr fеaturеsof thе skull. Thе vеrеrеnt layеrs of tissuе' thе есtodеrеndodеrmal (innеr) layеrs. Thеsе onе anothеr еarly in dеvеlopmеnt : Ьody as dеvеlopmеntprogrеssеs. l from thе middlе, or mеsodеrmal, iatеd with thе gill arсhеs, jaw' and lеlopmеntal origin diffеrеnt from Lrеdеrivеdfrom spесializеdсеlls of Likеwisе' thе musсlеs and nеrvеs :o onе anothеr in thеir origin; thе

m u s с l е sa s s o с i a t е dw i t h t h е g i l l a r с h е s ' j a w s , a n d m i d d l е - е a ro s s i с l е sа r е a l l dеrivеdfrom what is сallеd tЬe brапсhiomеric sеriеs of musсlеs, and thе nеrvеsthat sеrvе thеsе musсlеs all dеvеlop from thе samе group of сranial nеrvеs. All thеsеoЬsеrvationssupport thе аrgumеnt thаt jaws arе dеrivеd from gill аrсhеsand that thе middlе-еar ossiсlеs arе dеrivеd from jaws, and thus thаt mutationаnd sеlесtionсan indееd m
121

122 Аdаptаtitlп сomplех сomЬinations of сharaсtеrsthat togеthеr arе an adaptation for dispеrsing and сollесting pollеn. Flowеrs pollinatеd Ьy animals are сomparativеly largе' сolorful, and shapеd in ways that faсilitatеthе transfеr of pollеn. Somе flowеrs arе highly spесializеd to attraсt spесifiс pollinators, usually Ьy a сolor and/or fragranсе that аrе partiсularly attraсtivе to a pollinator. Thе sugary nесtar is thе rеwаrd offеrеd Ьy thе flowеr to thе pollinat,or, a rеward that draws thе pollinator's intеrеstto thе insidе of thе flowеr and sеtsthе pollinator in plaсе to piсk up and dеposit pollеn. Мany flоwеrs havе mаrkings that diгесt thе visitor toward thе nесtar,somе of whiсh aге visiЬlе only to animals likе insесts that sее in thе ultraviolеt (Ьlaсk-light)frеquеnсiеs.othеrs havе modifiеd pеtals or sеpals thаt sеrvе as a soft of landing strip on whiсh thе pollinator сan геst' аnd somе spесiеshаvе spесializеdstruсturеsto attaсh thе pollеn to thе pollinator. Two сlosеly rеlatеd spесiеs of monkеy flowеrs, Мimulus letaisii and М. саrdiпаlis, oссur along riparian hаЬitats in thе wеstеrn Unitеd Statеs (Figurе 2). Thеy sеgrеgаtе Ьy еlеvation, with М. lеtuisii oссurring at highеr еlеvations, and thеrе is а narrow rangе of еlеvation in whiсh thе spесiеs ovеrlap. Gеnеtiс analysеs show that еaсh spесiesis morе сlosеly rеlatеd to thе othеr than еithеr is to any othеr spесiеs of monkеy flowеr, so any diffеrеnсеs Ьetwееn thеm еvolvеd aftеr thеy last shаrеd a сommon anсеstor. Thе two spесies havе quitе diffеrеnt flowеrs. Thе spесiеs at thе highеr еlеvations' М. lешisii, is pollinatеd primarily Ьy Ьееs. It has pink flowеrs that arе rеlativеly widе and whosе pеtals form а horizontal landing strip; yеllow struсturеson thе landing strip appеar to guidе Ьееsto thе appropriatе part of

Figurе 2. Studiеsof thе сolor, sizе,shapе,and fеaturеsof thе flowеrsof two сlosеlyrеlatеdspесiеsof Мimulus hаvе illustratеdthе gеnеtiссоntrol of ссrmplехadаptations.Lеft: TЬe Ьluе flowег of М. letuisii,whiсh fеаturеsa ..landing plаtform'' for thе insесtsthаt transfеr pollеn Ьеtwееnflowеrs and ..guidеs,' that dirесt thе insесtstoward thе nесtarand thе rеproduсtivе struсturеsof thе flowеr. Right:Thе rеd flowеr ot М. саrdiпаlis,whiсh is a long, narrow' tuЬular flowеr with nесtaгаt thе Ьasе,rеaсhaЬlеЬy thе tonguеsof thе hummingЬirdsthаt sеrvеas thе pollinators.

the flowеr. Thе flowеrs produсtivе organs сonta thеy arе еnсountеrеd Ьy of thе insidе of thе flow flowеrs that laсk thе hol Ьy hummingЬirds, whiсl duсе largе quillltitiеs Of аnthеrs (mаlе org:rns)t that pollеn is dеpositеd. stamеns (fеmalе ()rgan

t h е r nn s r h е Ь i r d f е е d r . Еaсh flowег is wеll m: diffеrеnсеs Ьеtwееn tlrе plех aсlаptations for pс matсh of florvеr tсl polli Organs' and nесtar proс and sеlесtion сould hаv a сOmmon аnсеstor. O] сussеd еarliеr thаt gеnе diffеrеnсеs rеprеsеntth( сhаraсtеrs. lf this wеrе ехplаinеd vеry simply Ь аtе thе two flowеrs; shi nario, not srrЬstantially mottlеd to Ьlaсk. At tЬ matiс diffеrеnсеsarе Ьa еaсh of whiсh has vеry l or lеngth of thе anthеr Ь е е n v е г y m е t i с u l o u sa l thе floral traits. Of сor trеmе vlеWs. O u r k r l o w l е d g ео f p l p е t i n g h y p o t h е s е s .A l t t of sеpals, pеtals, st:rm g е n е s 'i t i s u n с l е a rh o w of thе rеproduсtivе str doсtion ratе. Thе routе to thе ans аnd thеir сollеaguеs Ьy lесular mеthods (Sсhе 2 0 0 3 ) . S с h е m s k еa n d i usеd Ь,v Mеndеl whеn l tееnth сеntury. Thеy pr Ьrids rarеly oссur in n: arе quitе hardy in grее lеaguеs nехt сrсlssеd h

lza

Adа|ltаtiсlп sесond gеnеration of so-сallеd Ьасkсrossеd plants with a variаЬlе mix of gеnеsfrom еaсh original spесiеs.Thеy thеn turnеd to molесular Ьiology' еmploying molесular markеrs thаt enaЬlеd thеm to аssoсiatеpагtiсular variations in floral сlraraсtеrsas sееn in thе vаrious сornЬinations of plants with diffеrеnсеsin molесular maгkегs on spесifiс loсаtions of сhromosomеs. Thе diffеrеnсеson thе сhromosomеs rеflесtthе loсations of gеnеsthat сontriЬutе to thе vагiаtion in thе flowеrs' Twеlvе individual сharaсtеrswеrе idеntifiеdarrd studiеd with this mеthod, whiсh rеvеalеd that thе truth rvas indееd somеrvlrеrе Ьеtwееn thе гwo еxtrеmе idеаs :rЬout gеnеtiс сontrol. A singlе gеrrе dеtеrminеd whеthеr thе flowеr was геd or pink. By plaсing f.lowеringhyЬrids and Ьaсkсrossеsin naturе, Sсhеmskе and сollеaguеsfound that thе сolor diffеrеnсеаlonе had an еnormous impaсt on whеthеr thе flowеr would Ье visitеd Ьy a Ьее or a hum-I.hе mingЬird. sсiеntists also found that whilе anothеr singlе gеnе madе a largе сontгiЬr.rtionto thе diffеrеnсеsin 9 of thе 12 floral traits, thеrе wеrе many gеnеs tlrаt madе smаllеr сontributions to onе or a small suЬsеt of thе traits. From thеsеrеsultsWе сan offеr somе plausiЬlе rесonstruсtionsof this сomplех adaptation. Thе еffесt of flowеr сo1or oп visitations suggеststhat a сhangе in a singlе 8еnе' that fоr сolor, сould initiatе thе еvolution of a spесialized flowеr. Diffеrеnt pollirrators attraсtеd to thе diffеrеnt сolors would ехеrt diffеrеnt sеlесtionpressurеson thе rеmainirrgtrzrits.Although it is unсlеar whеtlrеr thе largе sirrglе-gеnеeffесt on ninе traits prесеdеdoг followеd thе сhangеs in thе many othеr gеnеs that affесtеd onе or a fеw traits' thе ovеrall piсturе is of a singlе, simplе gеnеtiс сhangе (сolor) initiаting a stеpwisе proсеss of modifiсation and rеfinеmеnt whosе еnd produсts arе thе two сomplеx adаptations that wе now sее.Thе matсh of fеaturе to сirсumstanсе was not built qrritеas еasily as сhanging thе сoloration of moths Ьut did not rеquiге so mеtiсulous a molding as to strain сгеduliry' A finаl notе аЬout thе historiсal naturе of irdaptаtion is that it doеs not sееm pоssiЬlе that thе сhangеs in floral shаpе and rеpгoduсtivе сharaсtеrs .!Иithout сould havе prесеdеd thе сolor сhangе. variation in сolor аnd thе rеsultant diffеrеnсеin spесiеsof pollinators, thеrе would havе Ьеen no сonsistеnt sеlесtion prеssurеto mold divеrgеnt vаluеs of thе othеr сhагасtеrs.But onсе thе сolor diffеrеnсеSаppеarеd,tlrе divеrgеnt foraging of Ьееs and hum_ mingЬirds proЬaЬly сata|уzeda rаpid divеrgеnсе'This ехamplе illustratеsthе сontingеnсy inhеrеnt in thе еvolution of сomplеx fеaturеs in whiсЬ a singlе сhangе in a fеaturе сan promotе а сasсadе of suЬsеquеnt сhangеs that rеfinе its adaptation to nеw сirсumstanсеs.To rеturn to thе сritiquе bf Intеlligеnt Dеsign, wiсhout apprесiatingthе rolе of history, wе would Ье hаrd prеssеdto ехplain how аnс{why thеsе flowеrs divеrgеd so sulrstаntially. W H A т с A N I N D l V | D U A Ls Е L Е с т | o N N o т Е X P L A | N ? Our disсussion of adaptation hаs еmphasizеdhow thе fеаturеsof individr'rals arе moidеd Ьy thе aсtion of sеlесtion on thе avirilaЬlе gеnеtiс V;rrii1tion.

A fundamеntal tеnеt of I tеrs that еnhanсе thе fitnс wеll-Ьеing of а spесiеs.I: in pаrtiсul:rr for thе gughthis may ехplanatiоt-rfor all fеatu dividual sеlесtiсlnсomеs m i t е s ,i n w h i с l r n е a r l ya l | It is diffiсult to гесonstгu individuа| with :r fitnеss.

not геproсluсе. Thе kеy to rеsolving th that thе сol
Аdаptаtioп еd plants with a variaЬlе mix of l turnеdto molесular Ьiology, еmhеm to assoсiatеpartiсular variarious сomЬinаtionsof plants with fiс loсationsof сhromosomеs. Thе : ioсationsоf gеnеsthat сontriЬutе ifiеdand studiеdwith this mеthod' somеwhеrе Ьеtwееn tlrе two ехglе gеnе dеtеrminеd whethеr thе n g h у Ь г i d sа n d Ь а с k с r o s s е si n n а thе сolor differеnсеalonе had an 'ould Ье visitеd Ьy a Ьее or a humwhilе anothеr singlе gеIrеmadе a of thе 12 florаl traits, thеrе wеrе |nsto onе or a small suЬset of thе usiЬlеrесonstruсtionsof this сomlor olr visitatirlns suggеsts that a uld initiаtе thе еvoiutiсrnоf a spе_ сtеd to thе diffеrеnt сolors would еmainingtraits. Although it is un,n ninе traits prесеdеd or fсl]lowеd ' affесtеd onе oг a fеw traits, thе i с с h n n g е( с o I o г )i n i t i a t i n gа s t е p rt whosе еrrd pгоduсts irrе thе two : matсh оf fеaturе to сirсumstanсе lе сoloration of moths Ьut did not n сгеdulity. , of adaptation is that it doеs not hapе and rеpгoduсtivесharaсtеrs horrt vaгiation irr сolor аnd thе rеthеrс would hаvе Ьееn no сonsis,aluеsof thе otlrеr сhaгaсtеrs.But иеrgеntforаging of Ьееs аrrd humgеnсе.This ехamplе illustratеsthе omplеx fеaturеs in whiсh a singlе of suЬsеquеntсhangеsthаt rеfinе эturn to thе сritiquе оf Intеlligеnt ;tory' Wе would Ье hard гlrеssеdto .d so suЬstаntirrlly. oN Noт ЕХPLAIN? еd how thе fеаturеsof individuаls l t h е a v a i l a Ь | еg е n е t i с v а r i a t i o n .

A fundаmеntаltеnеt of Dагwinian еvtllution is that sеlесtion favors сharaсtеrsthаt еnhanсеthе fitrrеssof individuais; it doеs not nесеssarilуеnhanсе thе wеll-Ьеingof a spесiеs.Indееd,thе notion thilt еvolution hаs driеs, аnсl гhе сritiсzrlissuе in nlodеrn еvolrrtionaryЬiology is to diаgrrosеhow
I !.\

1 2 6 АdаDtаtiсlп parаsitе еvolutiot-t''in this volumе); a pathogеn tlrat nrultipliеs too quiсkly аnd kills its lrost tсlo quiсklу Ьеforе it сan bе trаr-rsmittеdto аnothеr host losеs out Ьесausе sеlесtion among familiеs Or groups (rеprеsеntеdЬy thе pathogen populаtiorr within an individual host) ovеrwlrеlms sеlесtion a m o n g i n d i v i d u a l s ( г е p r е s е n t е dЬ y t h е s t r u g g l еf o r p r o l i f е r i r t i o nw i t h i n а n individual host). ARЕ sтUDlЕs oF MlсRoЕVoLUтloN RЕLEVANт тo U N D Е R s т A N D IN G M A с R o Е v o L U т | o N A R Y P A т т Е R N s ? [t is сonvеniеnt to сharасtеrizеthе produсts of evolution as еithеr mlсroеvolution or maсroеvсrlutirln.МiсroeuoLutioll rеfеrs ttl small-sсirlесhangеs that arе dirесtly oЬsегvaЬlе, likе many o{ thosе disсtrssеdеагliеr (mеlanism irr moths, disеasе rеsistanсеin Ьaсtеriа, or insесtiсidеrеsistanсе).As wе havе disсussеd, miсroеvolution has Ьееn vеry thorouglrly doсurтеntеd and has Ьееn studiеd irr ways thаt mееt any tеst of sсiеntifiсrigi
sее that thеrе arе long not at аll, thеn Ьriеf in drеdgе dеsсriЬеd thе l< short intегvals as ptrnсl аssoсiаtion Ьеtwееn pu thе tеrm ptlпсtuаted еq Gotrld аrgrrеd that Ьot with nаturаl sеlесtiona on thе prеmisе that if sс

a prеd
First, neturаl sеlесtion isms to small-sсalесhar tlran natural sеleсtion quеnt assoсiation Ьеtw suggеststo Gould and phеnomеna, Ьut thеy h d u r i n g t h е 3 6 - y е a rh i s t

Thе сountеrargrrmе hаs thrее parts. First, v tion Ьy nаtural sеlесtr thаn thе ratеs i]ssoсlat Gа16pagоs finсhеs сan i n a p с l p u l а t i o ni n а s i r fall. In dгought yеаrrs sееdswith thiсk sеесlс< fесtivе at harvеsting su Bесausе tlrеrе is a gеn( finсhеs еxhiЬits largеr, to put this ratе of еvol sil rесоrd' it is l0,000 tегprеt as punсtuation inсonsistеnt witlr tlrе r tion' [f anything,wе r

fossil rесord. S е с o n d , s е l е с t i o l li s This, of сottrsе, is tlr.э Ьut hеrе it is importan tion сan onlу makе fi tаnсе to сhangе, mltst Darwin's linеs of argu саtе that domеstiс dtlg

Аdаptаtklп 1 o g е nt h a t m u l t i p l i е s t o o q u i с k l y r Ье transпrittеdto аnothеr host ]s or groups (rеprеsеntеdby thе ual host) ovеrwhеlms sеlесtion ugglе for prolifегаtiсlnwithin an

oN RЕLЕVANт тo г|oNARY PAттЕRNs? s of еvolutionas еithеr miсroevorеfеrsto smirll-sсalесhangеs that ;е disсussеdеаrliеr (mеlanism in .sесtiсidеrеsistanсе).As wе havе :horoughlydoсumеntеd and has :iеntifiсrigor' As а rеsшlt,it is not l сritiсsof evolution (sееthе rnain spесt and Рrospесt'' Ьy Еugеniе еvеntsthat wе аttriЬutеto еvoluliffегеntialpг
sееthat thеrе arе long intегvals whеn thе tгait in quеstion сhangеs littlе or not at all' thеn Ьriеf intеrvаls wlrеn thе tr:lit еvolvеs rapidlv. Gсlr-rldапd ЕldrеdgеdеsсriЬеdthе long, staЬlе intеrvals as stasis or еquiliЬrium and thе short intеrr.irisas punсtuаtions. Thеv also pointеd out that tlrеrе is oftеn an assoсiatiоrrЬеtwееnpunсtцations :rnd thе сlrigin of nеw spесiеs and сoinеd thе tеrm punctuаted equilibrium to dеsсriЬе thе еntirе pattеrn. Еldrеdgе and Gould aгguеd that Ьoth phasеs of pr'rnсtuatеdеquiliЬrium arе inсons,istеnt rvithnaturаl sеlесtionas a singlе urrdеrlyingсausе.Тhеir argtlmеntи,аs Ьasеd on thе prеmisеthat if sеlесtionwеrе suсh а unifying сausе' wе should oЬsеrvе a prеdominаrltPаttеГnof graduаI.сotrtinuousсhangе in сhагaсtеrs.Stаsis in сharaсtеrssuggеstsrеsistanсеto сhangе. Thе disсontinuity of punсtuations suggеstеd to thеm that somеthinghappеnеdto Ьrеak this rеsistanсеand сausе а suЬsеquеntpulsе сlf aссеlегatеdеvolutiorr. AlthougЬ Gould аnd Еldгеdgе'sargumеntshаvе еvolvеd during thе dеЬаtе rhatеnsuеdeftеr thеir first с.ssay,thеir argumеntshavе two unifying fеaturеs. First,natшralsеlесtionis pсlsitеdаs Ьеing еffесtivеonly in fir-rе_tuning organisп-rs to smirll-sсalесhangеsin thеir еrrvironmеnt.Sесоnd' somе proсеss othеr thаn naturirl sеlесtion must сomе into plaу to сausе punсtlliltions. Thе frе_ quеnt assoсiаtion Ьеtwееrrpunсtuirtionsarrd thе appеaranсе of nеw spесiеs suggеststo Gоuld and Еldrеdgе thаt this proсеss' whаtеvеr it is' сausеs Ьoth plrеnomеna,Ьut rhеy lravе аltеrеd tlrеiг prtlpоsеd mесhаnism tor this proсеss during thе 36-yеar history of punсtuatеd еquiliЬrium as an idеa. Thе сountеrargumеntin favor of natural sеlесtiсrnas a unifying Proсеss has thrееparсs.First, wе hаvе еmpiriсal еstimatеsсlf сhе r:rtеat whiсh еvoiution Ьy natural sеlесtionсаn oссur' and wе know that it сarr Ье muсh fastеr thаn thе ratеs assoсilltеdwith punсtllаtions irr thе fossil rесord' For ехamplе, Gal6pagosfinсhеsсan еvolvе a |0"Ь сhangе in avеragеЬody sizе or Ьill sizе in a populartionin a singlе vеar in rеsponsеto еithеr droughts or hеаvy rainfall. In drought yеlrrs ftlod avаilaЬility is low' thе Ьiгds mrrst rеly orr largе sееdswith thiсk sееdсoats and individuals rvith widе, hеavy Ьills arе morе еffесtivеat harvеstingsuсh sееdsand arе morе likеly to survivе and rеproduсе. Bесausеrhегеis ir gеrrеtiсЬаsis t
127

128

Аdаptаtioп of yеars ago. Thе fiгst appеaranсеof morphologiсally distinсt domеstiс dogs datеs to around 10,000 yеаrs аgO (Savolainеnеt al. 2002). Еrom suсh rесеnt Ьеginningswе havе Ьrееdsthat rangе in sizе from thе Сhihuahua to thе mastiff аnd in shapе from thе Pеkinеsе to thе lгislr wolfhound. If wе foсus on Ьody wеight alonе' thе rangе of avеragеwеights аmong Ьrееds is fгom around 1 kilogram for Сhihuahuas to 80 kilograms for mastiffs. This rangе еХсееds thе еntirе rangе of Ьody sizеs оf othеr spесiеsin thе family Сanidaе' whiсh inсludеs dogs, wсllvеs, foхеs, and othеr doglikе сarnivorеs (Finarеlli and Flynn 2006). It talls slroгt of wh:rt wе sее in thе ordеr Сaгnivora, whiсh inсludеs thе family Сanidaе along with othеrs' suсh as thе Fеlidaе (сats)or Ursidaе (Ьеars). Tеn thousand yеaгs of artifiсial sеlесtion havе thus Ьееn suffiсiеnt to gеnеratе a rangе сlf morphologiсal variation that is еquivalеnt to thе rangе wе Sееwlrеn wе loоk thrее or fottr stеps up thе tirхonomiс hiеrarсhy (spесiеs'gеnus' family, ordеr, сlass' phylunr, kingdom). Third, wе must сoIlsidег whеthеr thе prеsеnсеof stаsis' or long intеrvals сlf littlе or no сhangе, сan Lrеехplainеd Ьy natural sеlесtion.Thе Gal6pagos finсhеs again providе a good ссlnсеptual altеrnativе to ехplain why thеrе might bе long intеrv:rls of no apparеnt сhangе in thе fossil rесord. In drought yеars thеrе is intеnsе sеlесtion for inсrеasеd Ьill and Ьody sizе. In thе гаiny yеars that aссompаnv Еl Nino еvеnts' thе rеsourсе Ьаsе сhаngеs Ьесausе thеrе is an аЬundanсе of small, thin-shеllеd sеeds from diffеrеnt spесiеs of plants. Sеlесtion now favors smаllеr individuals with narrowег, morе forсеps-likе Ьills. This mеans that pеriods of sеlесtion for inсrеasеd Ьill sizе altеrnatе with pеriods of sеlесtion for dесrеasеd Ьill sizе, and in somе yеars thеге is in faсt nсl sеlесtion at all (GibЬs аnd Grzrnt 1987). ovеr thе nеarly thrее dесadеs in whiсh thеsе Ьirds hаvе Ьееn studiеd, thеrе has Ьееn no nеt сhangе in thе Ьill sizе of thе populaгion in spitе of strong еvi_ dеnсе for intеnse sеlесtion and rapid еvolution on a yеar-to.yеаr Ьasis (sее .!Иеinеr 1994 for а nontесhniсаl rеviеw of studiеs of Dаrwin's finсlrеs).Thе fossil rесord сould rеprеsеrrta frаgmеntеd,long-tеrm history of suсh shorttегm fluсtuating sеlесtion. Thе fossil rесord doеs nсrt rеpгеsеnt еaсh аnd еvеry yеar' and, in faсt, a dеfinесl pеriod in thе fossil rесord will rеprеsеnt a random rniхturе of thеsе diffеrеnt еpisodеs of sеlесtion.TЬе aсtual rаtе of еvolution that wе sее in thе fossil rесord is a long-tеrm avеragе of thе inсrеasеs and dесrеasеs and will inеvitaЬly undеrеstimatе thе true rаtе at whiсh orgаnisms сan еvolvе. A fоssil rесord of thе Gal6pagоs finсhеs may w е | |l o o k l i k е s t a s i s . In tlrе final аnalysis thеrе is nothing in thе fossil rесord that inhеrеntlyсon. tradiсts Dаrwin's daring idеa that natural sеlесtion is thе unifying mесhаnism. Organisms сап еvolve muсh morе гapidly tlran tlrеy appеar to еvolvе during punсtuations,and thе сapaсity of organismsto сhangе undеr sеlесtion far еxсееds thе сonstraints that arе apparеnt during stasis. Thе aЬsегrсеof сhangе during stasis пlay instеad Ье a statistiсalartifaсt of flrtсtuatingеvolution thаt traсks a fluсtuating еnvironnlеnt. But our argrrmеntsdo not provе that maсroеvolution is miсroеvolution writ largе;thеy mеrеly support thе viaЬility of naturаl sеlесtion as a singlе, ovеri1rсhingехplаnation. Thе rоot of

thе сontr
Horizons in thе Stuс

Adаprirtion is Ьеing sttrd of adaptation is еvidсnt, аrе ЬеginniIrgto dissесttl .!Ие havе а f аdaptations.

Ьut rr.е саllnot сonсlr'lt1 found arе gеnеrlll. Gеn() s е а r с l r а, n d e v с г s i . l t.ll f t v е r y с l if f е r е n tс ( ) n с | u 5 i O on thе Thе с
individual gеnеsth21tPro that tlrеу arе inl,rеritеdar p | а u s i Ь l еr ( )p o s i tе х t е n s in fасt thеге:rгеa fеrvstu ..Еvollttt thе пririn еssay rah Сharlеswoгth and th suggеststhаt thе !]еn()m not mеrеly a сoDstralllt. important quеstion thilt our сollесtivе viеr'vo1 it has сhangеd rnaгkесl11

portаnt for undеrstаnd this aгеir is lеаding to [а thе еvсllutitln mеntl оf thе сеll thе еvolr-rtiсln tivе аrеas of rеsеaгсh l

rеvсlllttion hаs еrraЬlеd n е W ( ) n е st o Ь е a s k е d . . and tlrс diffiсrrlty сlf aр thаt hilppеnеd ovеr a l otl-rеrttlpiсs, Ьut irr a dr o u r l p р r е с i e t i < l on Г t n t vеrr, diffс-rеntthan thеу Т h е s t t r d yс l f D а r ц ' i n аftеr (Jll Ibс Оrigitt ,

Аdа7ltаtiсlп lhologiсallydistirrсtdomеstiс dogs nеn еt al. 2002). From suсh reсеnt ze from thе Сhihuаhua to thе masе Irish wolfhound. If wе foсus on lightsamong Ьrееdsis from around ns for mаstiffs. This rangе еxсееds :сiеsin thе family Сanidaе, whiсh doglikе саrtrivorеs(Finarеlli and in thе order Cагnivora, whiсh inгs,suсh аs thе Fеlidaе (сats)or Urгtifiсial sеlесtion havе thus Ьееn 4iсalva;:iаtionthаt is еquivalеnt to )ur stеpsup thе taхonomiс hiеrar_ rylum,kingdom). rеsеnсеof stasis,or lorrg intеrvais nаtural sеlесtion.Thе Gal6pagos аltегnativеto ехplain why thеrе сhangе in thе fossil rесord. In 'r inсrеasеdbill and Ьody sizе. In эvеnts'tlrе rеsourсе Ьasе сhangеs thin-shеllеdsееds from diffеrent nаllеr individuаls with narrowеr' эеriods of sеlесtion for inсrеasеd ln for dесrеasеdЬill sizе, and in l l l ( G i b b sа n d G r a n t 1 9 8 7 ) .o v е r irds havе Ьееn studiеd, thеrе has p o p u l а t i o ni n s p i t е o f s t r о n g е v i ution on a yеar-to-yеarЬasis (sеe studiеsof Darwin's finсhеs).Thе , long-tеrmhistory of suсh shortlrd doеs not rеprеsеnt еaсh and r thе fossil гесord will rеpгеsеnra :s of sеlесtion.Thе aсtual ratе of is а long-tегm аvегagеof thе in. . undеrеstimatе thе truе ratе at rd of thе Galdpagos finсhеs may : fossil rесoгdthat inhеrеntlyсonsеlесtion is thе rrnifyirrg mесhaLpidlythan thеy appеar to еvolvе чanismsto сhangеundеr sеlесtion rnt during stasis.Тhе aЬsеnсе of ltiсal artifaсt of fluсtuating еvoluBut our аrgumеntsdo not provе largе;thеy mеrеly Support thе viаrсhing еxplаnаtion.Thе root of

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thесontrovегsyrеrnainstlrе difIiсulty of rесonсiling wlrat Wе сan study in thе shorttеrm rvith thе еnormously сliffеrеnttirтеsсalеof thе miri
Hоrizonsin thе Study of Adaptation Adaptаtion is Ьеing stuсliеdаt lеast as intеnsеly as еvеr. Althtlugh thе rеality fi1сg15 of adaptatiolris е','idеnt,trrtrn1, of it rеrnain unсlеаr. Foг схittт1llе,rr,е arеЬеginnirrgto dissесtthе gеnеtiсЬasis of аdаptatiоns' ;lartiсularlv сorrrplех adaptatiоns..й/е hlrr,еа fец.сlassiс studiеs likе tlrosе ()n thе mоnkеy flоwеrs, Ьut wе сannot ссlr-rсludе whеthеr thе pi-lttсrnsthat Sсlrеrnskеаnd сollеagr'rеs found arе gеnеral.Gеnomiс and protеomiс nrеtl-rods arе aссеlегatingthis rс_ sеarсh,and a vеrsion of tlris еsslr1. wгittсt-ra dссаdе frсttltnorr,rrrаyсlffсгsorrrс vеrv diffеrеntсtlnсlusiсlnsaЬout this tсlpiс. Tlrе сtlnstгаrints on thе raw mаtеriаl f
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Adаptаtiсlп argumеnt in Ьroad outlinе, it fеll to his suссеssors to disсovеr whiсh еlеmеnts of his argumеnt Wеrе possiЬlе in thеory, whiсh wеrе dеmonstraЬlе in praсtiсе, and whiсh wеrе roЬust to variаtions among spесiеs and сirсumstanсеs. T'hat so muсh of his original аrgumеnt геmains standing is a triЬutе to his gеnius; that so muсh rеmains to Ье disсovеrеd is a triЬutе to thе mаrvеls that adaptation offеrs and thе divеrsity of naturе th:rt it has сatzrlyzеd.

в|вLIoGRAPl{Y Ayala, F. J. 2006. Dаrшiп ttпd lпtеlligепt Dеsigп.lvIinnеapolis:FсlrtrеssPrеss. Bеnnеtt,М. V. L. 197l. Еlесtriс organs. In \W.S' Hoar and D. J. Randall' еds.' ЛisЙ Phуsiologу, voll. 5, З47_492. Nеw York: Aсadеmiс Prеss. Blouin, M. S. 1991. Proximatе dеvеlopmеntal сausеs of limЬ lеngth variаtion bеtwееn Hуlа сiпerеа and I7уkt grаtklsа (Anr'rra:Hylidае). .|ourпаl o|.Мorphobgl'209: 3 0 5 - 3 10 . 1992. Genettс сorrеlations among morphоmеtгiс traits аnd ratеs of growth and diffеrеntiation in thе grееn trее frоg, Hуlа сiпerеа. Еuolutioп 46:735-744' Brаdshaw, H. D., Jr., and D. \W' Sсhеmskе.2003. Allеlе suЬstitutionаt а flowеr сolour loсus рroduсеs a pollinatoг shift in monkе,vflowеrs,N,ltнrе 426: 776-178. Dаrwin, с. 1859. On thе origiп of Spесies.London: Iohn Murray. Dzidiс, S.,J. Suskoviс,and B. Kos. 2008. AntiЬiotiс rеsistanсеmесhanismsin bасtеria: Bioсhеmiсаl and gеnеtiс aspесts. Food Тechпolog1'апd Biote сhпсlklgу 46: 11'_21, Еldrеdgе, N., and S. J. Gоlrld. 1972. РunсtrratеdеquiliЬria:An altеrnativеto phylеtiс gradualism. In T' J. M. Sсhopf, ed., Мodеls iп Pаlеobiolсlgv,82-115. San Franсisсo: Frееman, Ссlopеr. Еisеlеy, L. 1958. Dаrtt,iп's Сепturу: Еuсllцtioп аnd thе Меп.V/h
МaсFаddеn, B. J. |992. l"rl the Fаmilу Еquidаc. N N{асNair,М. R. 1987.Hеa sуstеm' ТrепtJs ilt Есtll Маtsurnura, I]', and G. Vоss i n г h е r r , r ' t l - s p о t t еsJp i t Епtomtllogу 57: 9| |-9 N,lсPееk,М. ,\. l99.5. Мor1 damsеlfliсs сrf tw
сontеmP()гJг1.rd.rрt.rr t h e t p r о I n r t t еa r l a p т i е r Rеzniсk, D. N.' F. H. Shaw rаtе ()f еr,сllutionin nlt 275: |9З4-19З7. R е z n i с k . D . . . r n d. l . T r : l r i ' . G. [,atrdеr,еds.,Аdаpt' York: Aсаdеmiс Prеss. Roush, R. T., :rr-rd J. A. МсI асtrriсidеrеsistаnсе';ll, Rusе, М. |L):9.тhс Dапt,i Сhiс:rgo: Univеrsity of Sirvolаtnеn, P.' Y. P. Zhang. еvidеnсе foг an Еast i\s S с h е m s k е 'D . W ' , a n d H ' D е v о | u t i t l nс l f f l o r а l t г r i r Nаtioпаl Аcаdеmу o| S S с h m i d t - N i е l s е n 'K . | 9 9 О . l Сan-rЬгidgе:Сambгidgс S с h u l r е ,Р . ] \ l . 2 ( ) 0| . l . , l rirr t еvсllutiоlt.С| |mРаrсt! i I, S h u Ь i n ,N . Н . 2 0 0 2 . o r i g i r r of М
АJаptаlit lп

lссеssorsto disсovеr whiсh еlеmеnts , whiсh wеrе dеmonstraЬlеin praсs among spесiеsand сirсumstanсes. mains stаndingis a tributе to his gе_ еrеd is a triblltе to thе marvеls that -urеthat it has сirtаlyzеd.

;lgr. Мinnеаpolis:FоrтrеssPrеss. /' S. Hoar аnd D. J. Randаll, еds., FlsЙ Aсаdеrг'iсPrеss. саusеsof lirnb lеngth vаriаtion Ьеtwееrr Hylidaе)..|ourпаltl| Мсlrphohgу 2О9: эrphomеtriс trаits arrd rаtеs of growth ' HуIа сinerеа.Еuolиtioп 46:7З5-744. 003. Allеlе substitutionat a flowеr n monkеyflowers. Nаtltrе 426: -ondon:Jоhn Murray. lliсltiсrеsisтanсеmесhanisп-tsin balсtеriа: chnologу апd Biottlсhпologу 46: ||-21. tеd еquiliЬria:An irltеrnаtivеto phylеtiс bls iп Pаleсlbiolog1',82_115. San п апd thе Меп \WЬoDisсouerеd It. '. Епuiroпmепtаl Phуsiоlogу of thе :ago Prеss. aI statеrесonstruсtionof body sizе in Thе еffесtsсlf inсorрoгаting dаtа from

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МA: SinauеrAssoсiасеs. ng sеlесtionon Darrvin's finсhеs. Nаtиre tеd еquiliЬria:Thе tеmpo and modе of 115-151. 04. Compаring strеngths of dirесtional эп 58:21'З3.214З. B ioсhеmiсаl Аdаptаt itlп: М есh апism Nеw York: oxfоrd UrrivегsityPrеss. n с е1 9 6 : 1 \ 6 | - | | 6 6 . at maturity in Xiphсl1lhorиs. In G. K. у апd Еuolutioп o| Liuеbеаriпg Fishеs s, NJ: Prеntiсе Hall' rdаpratiоn t о h е a v y . m е г а |i ns a q u a t i с llutioп 45: 173_205, 1006.Gеnomiсsand thе irrеduсiЬlе 0 11 - 1 0 1 4 . ifiсationin thе еarly mаmmаliаn

Мaсtаddеn, B. '|. 1992. Frlssi!Нrуsеs: Sуstеmаtiсs, I,аlесlbkllogу,апd Еuolutioп of Nсw Yсlrk: Сambridgе LIrlivеrsityPrеss. the Fаmilу Р-t,1uidае. МасNair, М. R. l9[l7. Hеavy.lllеtаl lсsistаnсе in plirrrts-ir rт
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P U r p Ibeа с t e г i а

Molесular Еvolution FrаnсisсoJ. Aуаlа

Сyаnobасteriа Flavobaсtеria Thermotogа |es

Molесular biology hаs madе it possiЬlе to rесonstruсtthе сontinuity of suссеssion from thе original form of lifе, anсеstral to all living organlsms' to еvеry spесiеsnow living on еarth. Thе univеrsal trее of life, whiсh еmЬrасеs all known sorts of organisms, inсludеs thrее sеts of Ьranсhеs' Baсtегia, Ar. сhaеa' and Еukarya' whiсh all еmеrgеd from onе form of lifе, LUСA (Last Univеrsal Сommon Anсеstor; Figurе l). Al1 living organisms arе rеlatеd Ьy сommon dеsсеnt from a singlе form of lifе, rеprеsеrrtеdЬy thе trее trunk in thе figurе. Lifе may havе originatеd morе than onсе on our planеt-wе prеsеntly do not know-Ьut only onе form of lifе prospеrеd and lеft dеsсеndants, thе organisms that nоw populatе thе еarth. Baсtеria and Arсhaеa arе prokaryotiс miсrosсopiс сlrganisms.Еukarya arе organisms with сomplеx сеlls that сontаin sеvеral orgаnеllеs,onе of whiсh' thе nuсlеus, inсludеs thе hеrеditаry DNA. Most еukaryotiс organisms аrе singlе сеllеd and miсrosсopiс. Animals, plants, and fungi arе multiсеllular organisms, thrее of thе many Ьrаnсhеsof thе Еukaryа sеt. Тhе main Ьranсhеs of thе univеrsаl trее of lifе from LUсA, sеvеral Ьillion yеars ago' to thе prеsеnt havе Ьееn rесonstruсtеdon thе wholе and in many dеtails. Morе dеtails аЬout morе and morе Ьranсhеsarе puЬlishеd in sсorеs of sсiеntifiсartiсlеs еvеry month. Thе virtually unlimitеd еvolutionary infor. mation еnсodеd in thе DNA sеquеnсеof living organisms allows еvolutionists to rесonstruсtany еvolutionary rеlationshipsthat havе lеd to prеsеnt-day organisms, or among thеm, with as muсh dеtail as wаntеd. Invеst thе nесеssary rеsouгсеs(timе and lаЬoratory ехpеnsеs),and you сan hаvе thе answеr to any quеry with as muсh prесision as you want.

Мolесular Еvolution: Uniformity and Divеrsity In its unvеiling of thе naturе of DNA and thе workings сlf organisms at thе lеvеl of еnzymеs and othеr protеin molесulеs, molесular Ьiology hаs shown thе unity of lifе. Мorеovеr, molесular Ьiology has shown that thеsе molесulеs, DNA and protеins, hold informаtion aЬout an organism's anсеstry. t.)z

Figurе 1. Thе univеrsaltrее Baсtеria,Arсhaеa, and Еuk oгganismsarе rеlatеdЬy сo Ьy thе trее's..trurrk''(thеst using slоw-еvolvingriЬсlso

This has madе it possiЬlе l ously unknown and to сor Thе prесision with whiсh l еvidеnсе from molесular b Тhе molесular с
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to rесonstruсtthе сontinuity tlf suса n с е s t r a tl o a I I I i v i n g o r g a n i s m s ,r o tnivеrsaltrеe of lifе, whiсh еmЬraсеs thrее SеtSof Ьranсhеs,Baсtегia, Arfrom onе fоrrn сlf lifе, LUСA (Last . All living organisms arе rеlatеd Ьy lifе, rеprеsеntеdЬy thе trее trunk in norе than onсе on our planеt-wе lrm of lifе prospеrеdand lеft dеsсеnthе еarth. miсrosсopiсorganisms.Еukarya arе ain sеvеralorganеllеs,onе of whiсh, tJA. Мost еukaryotiс organisms arе llants, and fungi arе multiсеllulаr orthе Еukarya sеt. ее of lifе from LUCA, sеvеral Ьillion 'nstruсtеdon thе wholе and in many orе Ьranсhеsarе puЬlishеd in sсorеs rtually unlimitеd еvolutionary infor. lf living organismsallows еvolution'ionshipsthat havе lеd to presеnt-day :h dеtail as wantеd. Invеst thе nесеsеnsеs)'and you сan havе thе аnswеr you want.

'y and Divеrsity nd thе wоrkings of organisms at thе есulеs'molесular Ьiology has shown Ьiology has shown that thеsе molеation aЬout an оrganism's anсеstry.

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Figure1. Thе univеrsaltrее of lifе. Тhе thrееmajor groups of organisms, Baсtеria, Arсhaеa,and Еukarya' arе rеprеsеntеdЬy thе thrееmаin Ьranсhеs.All organismsarе rеlatеd Ьy сommon dеsсеntfrom a singlе fоrm of lifе, rеprеsеntеd by thеtrее's..trunk''(thеstraight.uplinе аt Ьottom).This trее was сonstruсtеd .Woеsе 1998.) usingslow-еvolving riЬosomalRNA gеnеs.(Adaptеdfrom

This has madе it possiЬlе to rесonstruсtеvolutionary еvеnts that wеrе prеviously unknown and to сonfirm and adjust thе viеw of еvеnts alrеady known. Тhе prесisionwith whiсh thеsееvеntsсan Ье rесonstruсtеdis onе rеason thе еvidеnсеfrom molесular biology is so сompеlling. Thе molесular сomponеnts of organisms arе rеmarkaЬly uniform in thе naturеof thе сomponеnts' as wеll as in thе ways in whiсh thеy arе assеmЬlеd and usеd.In all Ьaсtеria' arсhaеa' plants, animals, аnd humans' thе DNA сonsistsof a diffеrеnt sеquеnсе of thе samе four сomponеnt nuсlеotidеs (rеprеsеntеdаs A, с' G, and T; Figurе 2). Thе gеnеtiссodе, Ьy whiсh thе information сontainеdin thе DNA of thе сеll nuсlеus is passеd on to protеins' is virtually thе samе in all organisms (Figurе 3). Thе еnormously divегsе protеins in all sortsof organisms arе synthеsizеdfrom diffеrеnt сomЬinations, in sеquеnсеsof variaЬlеlеngth, of thе samе 20 amino aсids (listеd in Figurе З), although sеvеralhundrеdothеr amino aсids еxist. Similar mеtаЬoliс pathways-sеquеnсеs of Ьioсhеmiсalrеaсtions-aге usеd Ьy thе most divеrsе organisms to produсе еnеrgyand to makе up thе сеll сomponеnts. This unity rеvеals thе gеnеtiс сontinuity and сommon anсеstry of all organisms.Thеrе is no othеr rational Way to aссount for thеir molесular uniformity whеn numегous altеrnativе struсturеs arе in prinсiplе еqually likеly.Thе gеnеtiс сodе sеrvеs as an еxamplе. Еaсh partiсular sеquеnсе of thrееnuсlеotidеsin thе nuсlеar DNA aсts as a pattегn for thе produсtion of еxaсtlythе samе amino aсid in all organisms. This is no moге nесеssary than it is for a languagе to rrsеa partiсular сomЬinаtion of lеttеrs to rеprеsent a partiсular oЬjeсt. If it is found that сеrtаin sеquеnсеs of lеttеrsplanеt,trее' Woman-arе usеd with idеntiсаl mеanings in a numЬеr of diffеrеntЬooks, onе сan Ье surе that thе lаnguagеs usеd in thosе Ьooks arе of сommon origin.

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Gеnеs аnd protеins arе long molесulеs that сontаin information in thе sеquеnсе of thеir сolтponеnts in muсh thе samе way in whiсh sеntеnсеsof thе Еnglish languagе соntain information in thе sеquеnсе of thеir lеttеrs аnd words. Thе sеquеnсеsthаt makе up thе gеnеsarе passеd on from parеnts to offspring and arе idеntiсal from gеnеration to gеnеrаtion' еxсеpt for oсса. sionаl сhangеs introduсеd Ьy mutations. Сlosеly rеlatеd spесies havе vеry similar DNA sеquеnсеs;thе fеw diffеrеnсеsrеflесt mutations thаt oссurrеd sinсе thеir last ссlmmon аnсеstor. Spесiеsthat arе lеss сlosеly rеlatеd to onе anothеr ехhiЬit morе diffеrеnсеsin thеir DNA than thosе morе сlosеly rеlatеd Ьесausеmorе timе has еlapsеd sinсе thеir last соmmсln аnсеstor.This is

Figurе 3. The gеnеtiссodе:. mеssеngеrRNA and thе am nitrogеn Ьasе thyminе doеs thе othеr thrее nitrogеn Ьas adеninе (A)' сytosine (С), aI protеins (with thе thrее-lеt (Ala, A), argininе (Arg, R), ' (Сys, С), glyсinе (Gly' G), g ( H i s , H ) ' i s o l е u с i n е( I l е ,I ) ,l М)' phеnylalaninе(Phе,F), tyrosinе (Tyr' Y), tryptophа

thе rationalе for thе rесor аnd outсomеswiIl Ье rеvi As an illustгation, lеt ul Ьooks are 2oo pagеs long ехamination rеvеals that t for word, еxсерt that an r two Ьooks сannot havе l

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thаt сontain information in thе sе_ samеWay in whiсh sеntеnсеsof thе l thе sеquеnсеof thеir lеttеrs and ]еnеsarе passеd on from parеnts to ion to gеnеration, еxсеpt for oссa. Сlosеly rеlatеd spесiеs hаvе vеry rсеsrеflесt mutations thаt oссr.rrгеd i that arе lеssсlosеlv rеlatес{to o1-lе г DNA than thosе moге сlosеly rе. : thеir last сommon anсеstor.This is

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Figurе3. Thе gеnеtiссodе:сorrеspondenсеЬеtwееnthе 64 possiЬlесodons in messеngеr RNA аnd thе amino aсids (оr tеrminаtionsignals,..stop'').Thе nitrogenЬasеthyminеdoеs not ехist in RNA, whеrе urасil (U) tаkes its plaсе; тhеothеrthгееnitrogen Ьasеsin mеssеngеrRNA arе thе sаmе аs in DNA: adеninе(A), сytosine(С), and guaninе(G). Thе 20 amino aсids that makе up protеins(with thе thrее-lеttеrand onе-lеttеrstandard aЬЬrеviations)arе alaninе (Ala,A), argininе(Arg, R), asparagine(Asn, N), aspartiсaсid (Asp, D), сystеinе (Сys,С), glyсinе(Gly, G), glutamiсaсid (Glu, Е)' glutaminе(Gln. Q), histidinе (His,H), isolеuсinе(Ilе,I), lеuсinе(Lеu, [-)'lysinе (Lys' K), mеthioninе(Меt' (Phе,F)' prоlinе (Pro, P), sеrinе(Sеr'S), thгеoninе(Thr' Т), М), phеnylalaninе ryrosinе(Тyr, Y), tryptophаn(Trp' W), аnd vzrlinе(Val' V).

thе rаtionalе foг thе rесonstruсtion of еvolutionary history, whosе mеthods and outсomеs will Ье rеviеwеd latеr. As an illustrасion,lеt us assumе that wе arе сomparing two Ьooks. Both Ьooksarе 200 pagеs lorrg and сontain tlrе samе numЬег of сhaptеrs. Closеr ехaminationrеvеais thаt thе two Ьooks arе idеntiсal pagе for pagе and word for word, еxсеpt thаt an oссasional word-say, 1 in 100-is diffеrеnt. Thе two Ьooks сannot havе Ьееn writtеn indеpеndеntly: еithеr onе has bееn

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N\сllесulаrЕtlolt.ttion сopiеd froпr thе othеr, сlr Ь
InformationalМaсromolесulеs Nuсlеiс aсids and prorеins havе Ьееn сa||ed iп|'ormаtioпаl пшсromolесtllеs Ьесaцsе thеy arе long linеar molесulеs madе up tlf sеquеnсеs of unitsnuсlеotidеsin thе сasе of nuсlеiс aсids, amino асids in thе саsе сlf prсltеins_ tirat rеtаin сoirsidеr.rЬlеаmoLlnts of еvolutionary itrfсlrmirtion.Сomparisor-l of thе sеqцеnсе of thе сomponеnts in two mасгomolесulеs еstaЬlishеsthе numЬеrs that arе diffеrеnt.Bесausееvolution usually oссuгs Ьy сhanging onе unit at a tiпlе' thе numЬеr of diffеrеr-rсеs is an ir-rdiсationof tlrе rесеnсy of сoшmon аnсеstгy. Thе dеgrее of similarity in thе sеquеnсеof nшсlеotidеsor tlf amino асids сan Ье prесisеly quantifiеd. For ехamplе, in humans and сlriшpanzееsthе protеin molесulе сallеd сytoсhromе_с.whiсh sеrvеsа vitаl funсtion in rеspir a t i o n w i t h i n с е l l s ' с o n s i s t so f t h е s a m е ] 0 4 а m i n o а с i d s i n е х a с t l vt h е s a m е ordеr. It сliffеrs, horvеvеr, frоm thе сytoсhroп-tе_сof rlrеsr.rsrnonkе1.s Ьy 1 amino aсid, from that of horsеs Ьy 11 additiоnаl amino aсids, and from that of tuna Ьy 21 additional amino lrсiсls. Thе dеgrееof similaritу rеflесtsthе гесеnсyсlf сommon аnсеstгy.Thus infеrеnсеsfrom сomp.rгiltivеenаtопrr'аnd othеr сlisсiplinеsссlnсеrtlir-rg еvсllu. tionary history сan Ье tеstеd in molесular studiеs of DNA аnd protеins by еxamining thеir sеquеnсеsof nuсlеrltidеsand aminо aсids. TЬе authority of of gеnеs irnd thorrthis kind of test is ovеrwlrеlming:еirсl-rof thе thor"rsands sаnds of protеins сontаinеd in an orgаnism pгоvidеs an indеpеndеrrttеst of that organism's еvolutionary histor1'. Molесular еvolutionаrystudiеshavе thrее notaЬlе advаntagеsovеГсompariltivе anatoпly and thе tltlrеrсlassiсal сlisсiplinеs.onе is that thе informаtion is morе rеadily quаntifiaЬlе.Thе nr-rrrrЬеr of Lrnitsthаt arе diftЪrеlltis rеаdilу

еstaЬlishеd whеn thе sеqut diffеrеnt organisms. Thе s еvеn Ьеtwееn vегy diffеrеr parаtivе anatomy' for еха pinе trееs, and humаn Ьеiг protеin sеquеnсеs that сar multipliсity. Еaсh oгganis all rеflесt thе samе evoluti gеne or protеin does not si a sеt of spесiеs, additionа mattеr has Ьееn sеttlеd to Мoгеovег, thе widеly d opеn up thе opportunity с еnt dеgrееs of rеsolution il еvolving gеnеS to reсonst fastеr-еvolvin$ $еnеs to rе divеrgеd oгganisms. Gеnеs that еnсodе thе l еvolving gеnеS.Thеy havе ships among groups of or among Ьасtеria, аrсhаеa,; ing world), whiсh divеrgе among thе miсrosсopiс pl сomparеd with plants and of orgаnisms that divегgе tionеd еaгliеr, whiсh еvolv gеnеs' is usеd to dесiphеr l suсh as among humans, fi thе fiЬгinopеptidеs involvс ing thе еvolution of сlos maсaquеs' сhimpanzееs,a

Мolесular Phylogеni

DNA and protеins providt agеs from сommon nПCeS nеtiс сhangе that hаs oсс sееm at first that quantifyi Ье impossiЬIе Ьесausеit w isms that livеd in thе pаrst past arе somеtimes prеsе largеly disintеgratеd. Nev vidе informatiоn about aп As a spесifiс ехamplе' сhromе-с, whiсh is involvе

Мolесulаr Еuolution сopiеd' dirесtly or indirесtly, from ,, if еaсh сomponеnt nuсlеotidе of rplеtеsеquеnсеof nr-lсlеotidеs in thе э sеvеralhundrеd Ьooks, еaсh with .Whеn rd lеttеrs on еасh pagе. thе . . Ь o o k s ' (' g е n o m е s ) 'hеsе arе ехam. hе ,.lеttеrs''(nuсlеotidеs)givеs unargumеntsfor еvolution, Ьasеd on еt analogy, thе first аrgumеnt says : (thеsamе hеrеditarymolесuiе, thе lеs,аnd thе sanrе20 amino aсids in rary (thеsamеgеnеtiссodе), сannot ul-nеntсonсеrns similarity in thе sеhus thе sеquеnсеof amino aсids in similar tехts сannot Ье of indеpеn-

||ed iпformаtioпаl mасromolесulеs madе up of sеqшеnсеsof unitsnino асids in thе саsе of protеinsutiсlnary infornration. Ссlmpаrisсln Wo maсromolесulеsеstaЬlishеsthе tion usually OссursЬy сhanging onе ; is an indiсirtion of thе rесеnсy of ; е o f n u с l е o t i d е so r o f a m i n o a с i d s з, in humans and сhimpanzееs thе l i с h s е r v е sа v i г а |f u n с r i о ni n г е s p i 04 amino aсids in ехaсtly thе samе toсhromе-сof rhеsus monkеys Ьy additional аmino aсids, and from i.

еnсy of сommon anсеstry.Thus inothеr disсiplinеsссlnсеrningеvolulr studiеsof DNA and protеins Ьy and amino aсids. Thе authority of f thе thousandsof gеnеs and thousm providеsаn indеpеndеnttеst of :ееnotaЬlе advantagеsovеr сompar:iplinеs.onе is that thе informatiоn of units that arе diffеrеnt is rеadily

еstaЬlishеdwhеn thе sеquеnсеof units is known for a givеn maсromolесulе in diffеrеntorganisms. Thе sесond advantagе is that сomparisons сan Ье madе еvеnЬеtwееnvеry diffеrеnt sorts of organisms. Thеrе is vеry littlе that сomparativеanatomy, for еxamplе, сan say whеn organisms as divеrsе as yеasts' pinеtrееs,and human Ьеings arе сomparеd, Ьut thеrе arе numеrous DNA and protеin sеquеnсеsthat саn Ье сomparеd in all thrее. Thе third advantagе is multipliсity.Еaсh organism possеssеsthousands of gеnеs and prоtеins, whiсh all rеflесtthе samе еvolutionary history. If thе invеstigation of onе partiсular gеnеor protеin doеs not satisfaсtorily rеsolvе thе еvolutionary rеlationship of a sеt of spесiеs, additional gеnеs and protеins сan Ье invеstigatеd until thе mattеrhas Ьееn sеttlеd to thе satisfaсtion of thе invеstigator. Мorеovеr, thе widеly diffеrеnt ratеs of еvolution of diffеrеnt sеts of gеnеs opеn up thе opportunity of invеstigating diffеrеnt gеnеs for aсhiеving diffеrеnt dеgrееsof rеsolution in the trее of еvolution. Еvolutionists rеly on slowly еvolving gеnеs to rесonstruсt rеmotе еvolutionary еvеnts but inсrеasingly fastеr-еvolvinggеnеs to rесonstruсt thе еvolutionary history of morе rесеntly divеrgеdorganisms. Gеnеs that еnсodе thе riЬosomal RNA molесulеs arе among thе slowеstеvolvinggеnеs.Thеy havе Ьееn usеd to rесonstrцсt thе еvolutionary rеlationships among groups of organisms thаt divеrgеd vеry long ago: for еxamplе, among Ьaсtеria, arсhaеa, and еukaryotеs (thе thrее major divisions of thе liv. ingworld), whiсh divеrgеd morе tЬan2 Ьillion yеars ago (sее Figurе 1); or among thе miсrosсopiс protozoa (e.g., Plаsmodiиm, wЬiсh сausеs malaria) сomparеd with plants and animals, thе thrее of whiсh arе еukaryotiс groups of organisms that divеrgеd aЬout 1 Ьillion yеars ago. Сytoсhromе-с' mеn. tionеd еarliеr' whiсh еvolvеs slowly, Ьut not as slowly as thе riЬosomal RNA gеnеs,is usеd to dесiphеr thе rеlationships within largе groups of organisms, suсh as among humans' fishеs, and insесts. Fаst-еvolving molесulеs, suсh as thе fiЬrinopеptidеs involvеd in Ьlood сlotting, arе appropriatе for invеstigating thе еvolution of сlosеly rеlatеd animals, for еxamplе, thе primatеs: maсaquеs'сhimpanzееs, and humans.

Мolесular Phylogеniеsof organisms DNA and protеins providе information not only aЬout thе Ьranсhing of linеagеsfrom сommon anсеstors (сladogеnеsis)Ьut also about thе amount of gеnеtiс сhangе that has oссurrеd in any givеn linеagе (anagеnеsis).It might sееmat first that quantifying anagеnеsis for protеins and nuсlеiс aсids would Ье impossiЬlе Ьесausе it would rеquirе сomparison of molесulеs from organismsthat livеd in thе past with thosе from living organisms. Organisms of thе past arе somеtimеs prеsеrvеd as fossils, bцt thеir DNA and protеins havе largеlydisintеgratеd. Nеvеrthеlеss, сomparisons Ьеtwееn living spесiеs prov i d еi n f o г m a t i o na Ь o u t a n а g е n е s i s . As a spесifiс ехamplе, сonsidеr thе prеviously mеntionеd protеin сytoсhromе-с,whiсh is involvеd in сеll rеspiration. Thе sеquеnсеof amino aсids in

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Мoleсulаr Еuolution this protеin is krrown for many оrganisms, fгom Ьасtеria and yеаsts to insесts and hunrans;in animals' сytoсhromе_ссollsistsof 104 amiпo aсids. Whеn thе amino aсid sеquеnсеsof humans and rhеsus monkеys arе сomparеd' thеy arе found to Ье diffеrent at position 58 (isolеuсinе in humans' thrеoninе in rhеsus monkеys), Ьut idеntiсal at thе othеr 103 positions. Whеn humаns arе сompared with horsеs, 12 amino aсid diffеrеnсеSare found, and whеn horsеs arе сomparеd with rhеsusmonkеys, thеrеarе 11 amino aсid differеnсеs(Figuге4). Еvеn without knowing anything еlsе aЬout thе еvolutionary history of mammals, onе would сonсludе that the linеagеs of humans and rhеsus monkеys divergеd from еaсh othеr muсh morе rесеntly than they divеrgеd fгom thе horsе linеagе. Мorеovеr, it сan Ье сonсludеd that thе amino aсid diffеrеnсе Ьеtwееn humans and rhеsus monkеys mr-rsthavе oссurгеd in thе human linеаgе aftеr its sеparation fгom thе rhеsrrsmonkеy linеagе (sееFigurе 5).

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Figurе 4. Amino aсid sеquеnсеof сytoсhrоmе-сprotеinsin humans,rhеsus monkеys,and horses.Thе sеquеnсесonsistsof 104 amino aсids,еaсh rеprеsеntеdby a lеttеr.A dot indiсatеsthе samеamino асid as in humаns.Sее Fisurе 3 for thе namеsof thе аminо aсids.

Еvolutionary trееs aI еvolutionary histoгy of as gеnеra' familiеs, or t kinds of information rе nеsis. Figurе 5 illustratе thе rеlаtivе rеlationshiр of thе figurе, humans al to еасh othеr than еith shorvs that thе last сoп motе past than the last Еvolutionary trееs m; еaсh linеagе' or аnagеl last сommon аnсеstoг с h a n g е d i n t h е l i n е a g еt t o r h е s u s m o n k е y s .T h i that at position 58' п Figurе 4) havе thе sаnrс ,h е n t o n е ( i s o l е u с i n е )w aftеr it sеparatеd fгom 1

Мolесular Rесonst Sеvеral mеthods ехist f opеd for intеrprеtirrg п data; somе сan Ье usеd usеd in molесulaг еvol maхimum likеlihood. D|sтANсЕ MЕт|

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Figurе 5. Thе еvolutionоf сytoсlrromе-сamong hurnans,monkеys,and horsеs. Thе numbегsindiсаtеthе аmino :rсidrеplaсеmеnts that havе tаkеn pl:rсеin еасh Ьranсh of thе phylogеny.

A ..distanсе'' is thе num diffеrеnсеs arе mеаsurс data) or to сеrtаin maсI protеins or thе sеquеnс in Figurе 5 was oЬtain amino aсid diffеrеnсеs protеin. Thе amino aсid is rеflесtеdin thе numЬ геplaсеmеnt of onе am сlеotidе substitution in сasеs it rеquirеs at lеast numbеr of nuсlеotidе di еssary to aссount foг th( lutionary trее basеd on nuсlеotidе сhаngеs in еz

Мolеculаr Еuolution from Ьaсtеriaand yеasts to insесts Lsistsof 104 amino aсids' Whеn thе us monkеys arе сomparеd, thеy arе сinе in humans,thгеoninеin rhеsus .Wlrеn positions. humаns arе сom. ]еs arе found, and whеn horsеs arе 1 amino aсid diffеrеnсеs(F-igurе4). t thе еvolutionary history of mam_ of humans and rhеsus monkеys diy than thеy divеrgеd from thе horsе t thе amino aсid diffеrеnсе Ьеtwееn ;urrеd iir thе human linеasе аftеr its l (sееFigurе.5).

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nе-сprotеinsin humatrs,rhеsus ; of 104 aminсraсids,еaсh ;аmеamino aсid as in huI-rrans. Sее

Еvolutionary trееs arе modеls or hypothеsеs that sееk to rесonstruсt thе еvolutionaryhistory of taxa (i.е.,spесiеsor othеr groups of organisms, suсh as gеnеra'familiеs, oг ordеrs).As pointеd out е:lrliеr' thе trееs еmЬгaсе two kindsof information rеlatеd to еvolutionary сlrangе'сladogеnеsisand anаgеnеsis.Figurе .5illustratеsboth. Thе Ьrarrсhiпgгеlаtionshipsof thе trееs геflесt thе rеlativеrеlationshipsof anсеstry, or сlаdogеnеsis.Thus in thе right sidе of thе figurе,hunrаns and rhеsus monkеys 21геsееn to Ье morе сlosеly геlatеd to еaсh othеr than еithеr one is to thе horsе. Statеd anothеr way' this trее showsthat thе last сommon anсеstor to аll thrее spесiеslivеd in a morе rеmotеpast than thе last сommon anсеstor to humans and monkеys. Еvolutionarytrееs may also indiсаtе thе сhangеs that havе oссurrеd along еaсhlinеagе,or anagеnеsis.Thus in thе еvolution of сytoсhromе-с siпсе thе lаst сomnron zlnсеstor of humans and rlrеsus monkеys, сlr-rеarтino aсid сhangеdin thе linеagеthat Wеnt to httmаns Ьut none in thе linеаgе thaс Wеnt to rhеsusmonkеys' This ссlnсlusionis drаwn from thе oЬsеrvation (Figurе 4) that at positiоn 58, monkеys and horsеs (as wеll аs othеr animals; sее Figurе4) havе thе samе amino aсid (thrеoninе)'whilе humans havе a diffеrеntonе (isolеuсinе),whiсh thеrеforеmust hirvесhangеd in thе human linеagе aftеrit sеparatеd frolrl thе monkеy linеagе.

МolесularRесonstruсtionof Еvоlutionary History Sеvеralmеthods еxist for сonstruсting еvolutionary tгееs.Somе wеrе dеvеlopеd for intеrprеtingmorphologiсal data, othеrs for interprеting rnolесular datа;somе сan Ье usеd with еithеr kind of data. Thе main mеthods сurrеntly usеd in molесulaг еvolution arе сallеd distапсе. maхimum parsimony. and m a x i m u ml i k е l i h o o d ' DlsтANсЕ МЕтнoDs

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A ..distanсе''is thе numЬеr of diffеrеnсеsЬеtwееntwo kinds сlf organisms. Thе diffеrеnсеsarе mеasurеd with rеspесt to сеrtain traits (e.g., morphologiсal data)or to сеrtain maсromolесulеs (primarily thе sеquеnсе of amino aсids in protеinsor thе sеqttеnсеof nuсlеotidеs in DNA or RNA). Thе trее illustratеd in Figurе 5 was oЬtainеd Ьy taking into aссount thе distanсе, or numЬеr of amino aсid diffегеnсеs,among thrее orgагlisms with rеspесt to а Pаrtiсular protеin.Thе аmino aсid sеquеnсеof a protеin сontаins morе intЪrmаtionthаn is rеflесtеdin tlrе numЬеr of аmino aсid diffегеnсеsЬесausе in somе сasеs thе rеplaсеmеntoi onе amino aсid Ьy anothег rеquirеs no morе thurn onе nuсlеotidеsuЬstitution in thе DNA that сodеs for thе protеin, whеrеas in othеr сasеsit rеquirеs at lеast two nuсlеotidе сhangеs. TaЬlе 1 shows thе minimum numЬеrof nuсlеotidе diffегеnсеsin thе gеnеsof 20 sеparatеspесiesthat is nесеssaryto ассount for thе amino aсid diffеrеnсеsin thеir сytoсhromе-с. An еvolutionarytrее Ьasеdon tlrе data in TaЬle 1, shorvirrgthе minimum nuшЬегs of nuсlеotidе сhangеsin еасh Ьranсh, is illLrstгatеd in Figurе 6.

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The rеlationships Ьеtwееn spесiеs as shown in Figurе 6 сorrеspond fair|у wеll to thе rеlationships dеtеrminеd from othеr sourсеs' sllсh as thе fossil rесord.Aссording to thе figurе,сhiсkеns arе lеss сlosеly rеlаtеd to duсks and pigеonsthan to pеnguins, and humans and monkеys divеrgеd from thе othег mammalsЬеforеthе marsupial kаngaroo sеparatеdtrom thе nonprimаtе plaсеntals.Although thеsе еxamplеs аrе known to Ье еrronеous rеlationships, thе powеr of thе mеthod is apparent in that a singlе protеin yiеlds a fair|у aссuratеreсonstruсtionof thе еvolutionary history of 20 organisms that startеd to divеrgеmorе than 1 Ьillion yеars ago. Thе most сommon proсеdurе to transform a distanсе matrix into a phylogеnyis сallеd сlustеr analysis. Thе distanсе matrix is sсannеd for thе

141

1 4 2 Мoleсulаr Еuolutirlп smallеst distanсе еlеmеnt,and tlrе two taхa involvеd (say, human and monkеy in TaЬlе 1) arе joinесlat an intеrnal nodе, or Ьranсhing point. Thе matriх is sсannеd аgain fоr thе nехt-smаllеstdistirnсе,аnd thе two nеlv tахa (sаy' horsе zrnd donkеy) arе сlustеrеd. Thе proсеdurе is сontinuеd until аll taxa .!fhеn havе Ьееn joinес1. a distanсе involvеs a taxon thаt is alrеady }rertof a pгеviсlusсlustеr, thе avегagеdist:inсеis oЬtаiirесlЬеtwееnthе nеш'tахon irnсl thе prееxisting сlustеr (say, thе avеragе сlistanсеЬеtwееn humurnand horsе and monkеy anсl horsе).This simplе prtlсеdurеаssllmеsthаt thе ratе of еvo. lution is uniforrn alorrg :rll Ьranсl.rеs. Othеr distanсе mеthods (inсluding thе onе usеd ttl сonstruсt tlrе trее in Figurе 6) rеlax thе сondition of r"rniformrаtе and illlow for rrnеquаlratеs of еvolr.rtionalсlng thе brirnсhеs.or-rеof thе most ехtеnsivеl1,usеd ll-rеthodsсlf this kirrd is сallеd nеighЬor-joining.Thе шеthod starts' as Ьеforе,Ьy idеntifying thе smallеst distanсе in thе mаtrix and linking thе two tахa involvеd. Thе nехt stеp is to геmovе thеsе two tахa аnd сalсul:ltеa nеw mаtri-х in whiсh thеir distanсеs to othеr taхa arе rеplaсеd Ьy thе distanсе Ьеtwееn thе nodе that links thе tw.o taxa and all otlrеr taхa' Thе smallеst distаnсе in this nеw matrix is usеd for making thе nехt сonnесtion' rvhiсh will Ье Ьеtwееn trvсl othеr taхa or bеtwееn thе prеvious nodе and a nеW taхon. Thе proсеdurе is геpеаtеduntil all taxа havе Ьееn сonnесtес]with Ollе an()thегЬy intсгvеning nodеs. l oNY MЕтнoDs М A x l M U r . 4 . P A R sМ Мaхimum-parsimony mеthods sееk to rесonstruсtthе trее that rеqrrirеsthе fеwеst(i.е.,most parsimorrious)numЬеr of сhаngеsstlnrmеdltlongаll Ьгаrrсhеs. This is а rеasorraЬlеassumption Ьесausеit usually will Ье tlrе rnost Iikеly. But еvolution may not nесеssarilyhavе oссurrеd follorving a minimum path, Ьесаusе thе sarnе сlrangе irrstеadnray havе
from thе linеagеs that . vorеs' fоr examplе' dol gеthеr Ьесausе they pol сommon anсеstor bran( and сoyotеs.

MAХ|МUМ-LlKЕL

Мaximum-likеlihood mt availaЬlе data. Thеy rе< would makе it possiblеt. сhangе. For ехamplе, as morе likеly than transv proЬaЬility must Ье assl p г o Ь а Ь i l i t i е sf o r е a с h i n с trее is thе onе with thе I all possiblе trееs' Мaximum-likеlihood numЬеr of taхa is largе whiсh thе proЬability m of taхa. With 10 taхa, taxa, tЬе numЬеr of pos Еvеn with powеrful сoг h i Ь i t i v е i f t h е n u m Ь е ro t t i m е r е q u i r е d .H е u г i s t i с siЬlе tгееs is еxаminеd, а sтAт|sтlсAL

AP|

Thе statistiсal dеgrее o1 and maximum-likеlihoо strapping. It сonsists of data point at random aг random sampling proсе Ьootstrap valuе for еaсl all spесiеs dеrivеd from bootstrap valuеs aЬovе thosе with Ьootstrap val

lVlolесular Phylogе

Thе mеthоds for oЬtai mously improvеd in rес. gеnеs havе bееn sеquеnс has Ьееn sеquenсеdin r

МoleсulаrЕuolцtion < ai n v o l v е d( s a y ,h u m а n а n d m o t r dе, сlr Ьranсhingpoint. Тhе matriх tanсе,and thе two nеw tаха (say' lсеdurе is сontinuеd until all tахa 3s а taхon tlrat is аlгеirdypart of a ltainеdЬеtwеегtthе nеw taxon arrd istanсеЬеtwееnhuman аrndhoгsе зduгеassutt-tеs thаt tl-rеrаtе of еvoonе usеd to сonstruсt thе trее in .atе i1ndallor,vfoг ltllс'qual ratеs сlf most ехtеnsivеlyusеd mеthods of еthod starts,аs Ьеforе,Ьy idеntifylirrkirrgrhе rrvo taха irr'',olvеd.Tlrе j с a l с u l а t еa n е w m а t r i х i n w h i с h Ьy thе distirnсеЬеtwеегtthе nodе . Tlrе srnallеstdistarrсе in this rrеw эсtiorr,whiсh will Ье Ьеtwееn trvo rnd a nеw taх()n.Thе proсеdurе is . J ц ' i г h ( ) n е : l I 1 ( ) t h е rl ) \ . i l . l г с г V е l l i l l g

s сonstruсtthе trее that rеquirеs tЬе :hаngеssummеdalong аll Ьrarrсhеs. u s u а l l yw i l l Ь е t h е r т o s t l i k е l y . B u t " е df o l l o w i n gа m i n i m u m p a t h ' Ь е oссuгrеd indеpеlrdеrrtli,along diflve involvеd intеrmеdiatеstеps. е thаt involvе a singlе stеp, may Ье : forrr nuсlеotidе Ьasеs in DNA, с1.. ; of a family of rеlatеd molесulеs rnd guaninе (G) Ьеlong to a family rithin а DNA sеqrrеnсefrom oпе е purinе to anothеr (A.'G), сallеd с h а n g , fеr с l mа p u r i n е t t l а p y r i m i , сallеd а transvеrsion.Parsimon1, labrlittеsof сlссurrеnсеif thеy irrе tеd to сladistiсs'a vеrУ formalistiс ехtеnsivеiyusеd with nloгphologifеaturеin сladistiсsis tlrе idеntifi. lomorphiс trаits.A synapomorpЬiс lrs Ьесausеtlrе formеr inhеritеd it hе tгait аftеr its linеagе sеpагatеd

from thе linеages that wеnt to thе othеr taхa. In thе еvolution of сarnivorеs,for ехamplе, domеstiс сats' tigеrs' and lеopards arе сlustеrеd togеthеrЬесausе they possеss rеtraсtaЬlе сlaws' a trait aсquirеd aftеr thеir сommon anсеstoг Ьranсhеd off from thе linеagе that lеd to dogs, wolvеs, аnd сoyotеs. MAxlMUM-L|KЕL|HooD МЕтHoDs Mахimum-likеlihood mеthods sееk to idеntify thе most likеly trее, givеn thе avаilaЬlе data. Thеy rеquirе that an еvolutionary modеl Ье idеntifiеd that would makе it possiЬ1еto еstimatеthе pгoЬabiiity of еaсh possiblе individual сhangе.For еxamplе, as is mеntionеd in thе prесеding sесtion' transitions arе morе likеly than transvегsions among DNA nuсlеotidеs, Ьut a partiсular proЬaЬilitymust Ье assignеd to еaсh. Ali possiblе trееs arе сonsidеrеd. Thе proЬaЬilitiеsfor еaсh individual сhangе arе multipliеd for еaсh trее. Thе Ьеst trееis thе onе with thе highеst probaЬility (or maхimum likеlihood) аmong all possiЬlеtrееs. Мaхimum-iikelihood mеthods arе сomputationally ехpеnsivе whеn thе numЬеr of taхa is largе Ьесausе thе numЬеr of possiЬlе trееs (for еaсh of whiсh thе proЬаЬility mцst Ье сalсulated)grows faсtorially with thе nцmbеr .!7ith of taхa. 10 taхa, thеrе arе aЬout 3.6 million possiЬlе trееs; with 20 taхa' thе numЬеr of possiЬlе trееs is aЬout 2 followеd Ьy 18 zeгos (2х1018). Еvеn with powегful сomрцtеrs' mаximum-likеlihood mеthods сan bе prohiЬitivе if thе numЬеr of tахa is largе, Ьесausе of thе сonsidеrаЬlе сompцtеr timе геquirеd.Hеuristiс mеthods еxist in whiсh only a suЬsamplе of all possiЬlеtrееsis еxаminеd, аnd thus an еxhaшstivеsеarсh is avoidеd. sтAтIsт|сAL APPRAIsAL oF ЕVoLUт|oNARY тRЕЕs Thе statistiсаl dеgrее of сonfidеnсе of a trее сan Ье еstimatеd for distanсе and maхimцm-likеlihood trееs. Thе most сommon mеthod is сallеd Ьootstrapping.It сonsists of taking samplеs of thе data Ьy геmoving at lеast onе data point at random and thеn сonstruсting a trее for thе nеw data sеt. This random sampling proсеss is rеpеatеd hundrеds or thousands of timеs. Thе bootstrap valuе for еaсh nodе is dеfinеd Ьy thе pеrсеntagе of саsеs in whiсh all spесiеsdеrivеd from that nodе appеar togеthеr in thе trееs. Nodеs with Ьootstrap valuеs aЬoуe 90oЬ arе rеgardеd as stаtistiсally strongly rеliaЬlе; thosеwith bootstrap vаluеs Ьelow 70oЬ arе сonsidеrеd unrеliаblе.

Мolесular Phylogеny of Gеnеs Thе mеthods foг oЬtaining thе nuсlеotidе sеquеnсеs of DNA havе еnormouslyimprovеd in rесеnt yеars аnd havе Ьесomе laгgеly аutomatеd. Many gеnеshavе Ьееn sеquеnсеd in numеrous organisms' and thе сomplеtе gеnomе has bееn sеquеnсеdin many spесiеs,ranging from humans to Ьaсtеria. Thе

14З

144

Мoleculаr Еuolиtion usе of DNA sеquеnсеs has Ьееn partiсularly rеwarding in thе study of gеnе dupliсations. Thе gеnеs that сodе for thе hеmсlgloЬins in humans and сlthеr mammals providе a good еxamplе. Knowlеdgе of thе amino aсid sеquеnсеs of thе hеmogloЬin сhains and of myogloЬin, a сlosеly rеlatеd protеin, has madе it possiЬlе to rесonstruсt thе еvolutionary history of thе dupliсations thаt gavе risе to thе сorrеsponding gеnеs. But dirесt еxamination of thе nuсlеotidе sеquеnсеs in thе gеnеs that сodе for thеsе protеins has shоwn that thе situation is moге сompleх, and also morе intеrеsting,than it appеars from thе protеin sеquеnсеs. DNA sеquеnсеstudiеs on human hеmogloЬin gеneshavе shown that thеir numЬеr is grеater than prеviously thought. Hеmoglobin molесulеs arе tеtramеrs (molесulеsmadе of four suЬunits)that сonsist of two polypеptidеs (rеlativеly short protеin сhаins) of onе kind and two of anothеr kind. In еmЬryoniс hеmogloЬin Е, onе of thе two kinds of polypеptidе is dеsignatеd с; in fеtal hеmoglogin F, tt ls Т; in adult hеmogloЬin A, it is F; and in adult hеmogloЬin A,, it is 6(hеmogloЬin A makеs up аЬout 98"Ь of humаn adult hеmoglobin, and hеmogloЬin A, aЬout 2"Ь|. Thе othеr kind of polypеptidе in еmЬryoniс hеmogloЬin is (; in Ьoth fеtal and adult hеmogloЬin, it is a. Thе gеnеS that сodе for thе first group of polypеptidеs (е, y, 0, and ф аге loсatеd on сhromosomе 11; thе gеnеsthat сodе for thе sесond group of polypеptidеs (( and a) arе loсatеd on сhromosomе 16. Thеrе arе additional сomplехitiеs.Two y gеnеseхist (known аs G,and A/' as do two 0 gеnеs (сt' and a,). Furthеrmorе, thеrе arе two B psеudogеnеs (уB, and VF,) and two gpsеudogеnеs (уa,and {{х,),as wеll as a (psеudogеnе. Thеsе psеudogеnеsarе vеry similаr in nuсlеotidеsеquеnсеto thе сorrеsponding funсtional gеnеs, Ьut thеy inсludе tеrminating сodons and othеr mutations that makе it impossiЬlе for thеm to yiеld funсtional hеmogloЬins. Thе similarity in thе nuсlеotidе sеquеnсеsof thе polypеptidе gеnеs and pseudogеnеs of Ьoth thе a and B gene familiеs indiсatеs that thеy arе all homologous-that is' that thеy havе arisеn through various dupliсations and suЬsеquеnt еvolution from a gеnе аnсеstral to all. Morеovеr, homology also ехists Ьеtwееn thе nuсlеotidе sеquеnсеsthat sеparatе onе 8еnе from anothеr. Thе еvolutionary history of thе gеnеs for hеmogloЬin and myogloЬln is sum.

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Nlultipliсity and Ratе Hеtеrogеnеity

Figurе 7. Еvolutionaryh whiсh аnсеstralgеnеsdt а p p r o x i m a t еt i m е sw h е y е a г s( М Y 1 a g o .T h с t i n unсеrtаin.

сytoсhromе-с сonsists of only 104 аmino aсids, еnсodеd Ьy 312 nuсlеotidеs. N е v е г t h е l е s st, h i s s h o r t p r o t е i n s t o r е s е n o г m o u s е v о l u t i o n a r yi n f o r m a t i o n ' whiсh madе possiЬlе thе fairly good approхimation' shown in Figurе 6, to thе еvolutionary history of 20 verу divеrsе spесiеs ovеr a pеriod longеr than 1 Ьillion yеars. Сytoсhromе-с is a slowly еvolving protein. Widеly diffеrеnt spесiеs havе in сommon a largе proportion of thе amino асids in thеir сytoсhromе.с, whiсh makеs possiblе thе study of gеnеtiс diffеrеnсеs Ьеtwееn organisms only rеmotеly rеlatеd. Foг thе samе rеason, howеvеr, соmparison

of сytoсhromе-с molес twееn сlosеly rеlatеd сytoсhromе-с in humz vеrgеd 6_8 million yеa divеrgеd from thеir сol only onе amino aсid rе

marizеd in Figurе 7.

Мolесulаr Еuolutioп rly rеwarding in thе study of gеnе hеmogloЬinsin humans and othеr

gеnеs hemoglobin gеnеs myogIobin

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s of thе hеmogloЬin сhains and of nadе it possiЬlеto rесonstruсt thе hat gavе risе to thе сorrеsponding еotidе sеquеnсеsin thе gеnеs that rе situation is moге сomplех, and r thе protеin sеquеnсеs. globin gеnеshavе shown that thеir шght. HеmogloЬin molесulеs arе :s)that сonsistof two polypеptidеs Ldand two of anothеr kind. In еmls of polypеptidе is dеsignatеd s,.in loЬin A, it is B; and in adult hеmoaЬout 98% of human adult hеmoThе othеr kind of polypеptidе in and adult hеmogloЬin,it is a. Thе pеptidеs(е, Ъ 0, and ф arе loсatеd ,r thе sесondgroup of polypеptidеs r genеsехist (known as G,and A/, lorе' thеrе arе two B psеudogеnеs х, and уа,\, as wеll as a (psеudon nuсlеotidе sеquеnсеto thе сorrе_ rdе tегminatingсodons and othеr n to yiеld funсtional hеmogloЬins. rсеs of thе polypеptidе gеnеs and amiliеs indiсatеs that thеy arе all n through various dupliсations and al to all. Morеovеr, homology also tatsеparatеonе gеnе from anothеr. rеmogloЬinand myogloЬin is sum-

)rty асids,еnсodеd Ьу З1'2nuсlеotidеs. iormous еvolutionary information, rохimation, shown in Figurе 6, tсl е spесiеsovеr a pеriod longеr than еvolving protеin. \Х/idеly diffеrеnt rtion of thе amino aсids in thеir tudy of gеnеtiсdiffеrеnсеs Ьеtwееn s a m ег е a s o n h. o w е v е r ,с o m p a r i s o n

1,100N/Y Figurе7. Еvolutionaryhistory of thе glоЬin gеnеs.Thе forks indiсatеpoints at whiсhanсеstralgеnеsdupliсаtеd,giving risе to nеWgеnеlinеagеs.Thе timеs whеn thеsеdupliсations oссurrеd arе indiсatеd in millions of appr.oхimatе yеars(МY) ago.Thе timе whеn thе dupliсationof с' and сr, oссurrеdis unсеrtaln.

of сytoсhrome-с molесulеs сannot dеtеrminе еvolutionary rеlationships bеtwееn сlosеly rеlatеd spесiеs. Fоr ехamplе, thе amino aсid sеquеnсе of сytoсhromе-с in humans and сhimpanzееs is idеntiсal, although thеy divеrgеd6_8 million yеars ago; Ьеtwееn humans and rhеsus monkеys, whiсh divегgеdfrom thеir сommon anсеstor З5_40 million yеars ago' it diffеrs Ьy only onе amino aсid rеplaсеmеnt.

145

146

Мoleculаr Еuolutioп Protеins that еvolvе morе rapidly than сytoсhromе-с сan Ье str'rdiеdin or. dеr to еstaЬlish phylogеnеtiс rеlationships Ьеtwееn сlosеly rеlatеd spесiеs. Somе protеins еvolvе vеry fast; thе fiЬrinopеptidеs-small protеins that arе involvеd in thе Ьlood-сlotting proсеss-arе suitaЬlе for rесonstruсting thе phylogеny of rесеntly еvolvеd spесiеs' sцсh as сlosеly rеlatеd mammals. othеr protеins еvolvе at intеrmеdiatе ratеs; thе hemogloЬins, for еxamplе' сan Ье usеd to rесonstruсt еvolutionary history ovеr a fairly Ьroad rangе of timе (sееFigurе 8). Onе grеat advantagе of molесulаr еvolution is its multipliсity, as notеd

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O n е с l l n s p i с u o t ' tаs t t r i h o m < l I o g o um s olесul plе. pгopoгtionsоf nL е v o l u t i o n a r yс h a n g ес t o D N A o r p r o г е i n st h tion. Studiеs of mсllе maсromсrlесulеsmay s It wаs first oЬsеrvе еnсеs Ьеtwееnhomolt n е a r l y p r o p с l r t i o n a lt t r o r . I f r h е г a t е o f е rt sаmеin thс еvoIuгiо D N A s е q u е n с е sW o u q u е n с е sс o u l d r h е n h е ing еvеnts of a phyl oссurrеd. Сonsidеr, for ехam gеnе сoding for сytoс} с o u l d d е t е r m i n еt h е t simply Ьy ехamining Ь r а n с h .o n е w o u I dn е sourсе' suсh as thе tt t i m е r h a t е l а p s е di n а r T h е m o l е с u l а rе v o сloсk, likе a watсh с

Мolесиlаr Еuolutioп сytoсhromе-ссan Ье studiеd in orps bеtwееnсlosеly rеlatеd spесiеs. ropеptidеs_small protеins that arе -аrе suitaЬlе for rесonstruсting thе suсh as сlosеly rеlаtеd mammals. ttеs;thе hеmogloЬins,for ехamplе, histoгy ovеr a fairly Ьroad rangе o{ olution is its multipliсity, as notеd

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еaгliеr.Within еaсh organism afе tЬousands of gеnеs and protеins; thеsе еvolvеat diffеrеnt rаtеs, Ьut еvеry onе of thеrrrrеflесtsthе sаnrееvolutionary е\.еnts.Sсiеntistsсan oЬtain grеatеr and grеatеr aссuraсy in rесonstruсting thе еvolutionary phylogеny of any group of organisms Ьy inсrеasing thе numЬеrof gеnеsinvеstigatеd.Thе rangе of diffеrеnсеsin thе ratеs of еvolution ЬеtwееnЕ]еI.lеs opеns up thе opportunity of invеstigatingdiffеrеr-rt sеts of gеnеsfoг aсhiеvil-lgdiffеrеnt dеgгееsof rеsсllutiorrin thе trее of litЪ; slowly еvolvingЕ]еnеsсаn bе usеd to study rеmotе еvolutionary еvеllts. Еvеn gеnеs thatеnсоdеslorvly еvоlving protеins сan Ье usеful for rесonstruсtingthе еvolutionaryrеlationshipsЬеtwееnсlosеly rеlatеd spесiеsЬy ехaminаtion of thе геdundantсodon suЬstitutions (nr.rсlеotidе suЬstitr'rtions that do not сhangе thе еnсodеd аmino aсids), thе intrоns (nonсoding DNA sеgmеnts intеrspеrsеdamong thе sеgmеrrtstlrirtсodе foг аmino асids), or othеr nonсoding sеgmеntsof tlrе gеnеs (suсh as rlrе sеquеnсеsthat prесеdе and tollow thе еn. сoding portions сlf gеnеs);thеsе gеnеrally еvolvе muсh fastеr than thе nuсlеotidеsthat spесify thе amino aсids.

Thе Мolесular Сloсk of Еvolution

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147

148

Мoleculаr Еuolutioп stoсhastiс сloсk' likе radioaсtivе dесay. In a stoсhastiссloсk thе proЬaЬility of a сеrtain amount of сhangе is сonstant (for еxаmplе, a givеn quantity of atoms of radium.226 is еxpесtеd' through dесay, to Ье rеduсеd Ьy half in 1',62Оуears), although somе variation oссurs in thе aсtual amount of сhangе. Ovеr fairly long pеriods of timе a stoсhastiс сloсk is quitе aссuratе. Thе еnormous potеntial of thе molесular еvolutionary сloсk liеs in thе faсt that ..tiсks', еaсh gеnе or protеin is a sеpаrаtе сloсk. Еaсh сloсk at a diffеrеnt ratе-thе ratе of еvolution сharaсtеristiс of a pаrtiсular gеnе or protеin-Ьut еaсh of thе thousands and thousаnds of gеnes or protеins providеs an indеpеndеnt mеasurе of thе samе еvolutionary еvеnts. Еvolutionists havе found that thе amount of variation obsеrvеd in thе еvo. lution of DNA аnd protеins is grеаtеr than is ехpесtеd from a stoсhastiс ..ovеrdispеrsеd,'' or somеwhat еrratiс. сloсk-in othеr words, thе сloсk is Тhе disсrеpanсiеs in еvolutionary ratеs along diffеrеnt linеagеs arе not ехсеs. sivеly largе, howеvеr. So it is possiЬlе, in prinсiplе, to timе phylogеnеtiс еvеnts with as muсh aссuraсy as may Ье dеsirеd,Ьut morе gеnеs or protеins (aЬout two to four timеs as many) must Ье еxaminеd than would Ье rеquirеd if thе сloсk wеrе stoсhastiсally сonstant. Thе avеragе ratеs oЬtainеd for sеvеral protеins takеn togеthеr Ьесomе a fair|у prесisе сloсk, partiсularly whеn many spесiеs arе studiеd and thе еvolutiоnary еvеnts involvе long timе pеri. ods (on thе ordеr of 50 million yеars or longеr). This сonсlusion is illustratеd in Figurе 9, whiсh plots thе сumulativе nцmЬеr of nuсlеotidе сhangеs in sеvеn protеins against thе dаtеs of divеrgеnсе of 17 spесiеsof mammals (16 pairings) as dеtеrminеd from thе fossil rесord. Thе ovеrall ratе of nuсlеotidе suЬstitution is fairly uniform. Somе primatе spесiеs (rеprеsеntеdЬy thе points bеlow thе linе at thе lowеr lеft of Figurе 9) appеar to havе еvolvеd at a slowеr ratе than thе avеragе for thе rеst of thе spесiеs.This anomaly oссurs Ьесausеthе morе rесеnt thе divеrgеnсе of any two spесiеs,thе morе likеly it is that thе сhangеs oЬsеrvеd will dеpart from thе avеragе еvolutionary ratе. As thе lеngth of timе inсrеasеs, pеriods of rapid and slow еvolution in any linеagе arе likеly to сanсеl onе anothеr out. Еvolutionists havе disсovеrеd, howеvег, that molесular timе еstimatеs tеnd to bе systеmatiсally oldеr than еstimatеs Ьasеd on othеr mеthods and' in. dееd, to Ье oldеr than thе aсtual datеs.This is a сonsеquеnсеof thе statistiсal propеrties of molесular еstimatеs' whiсh arе asymmеtriсally distriЬutеd. Bесausе of сhanсе, thе numbеr of molесular diffеrеnсеs Ьеtwееn two spесiеs may Ье largеr or smallеr than еxpесtеd. But ovеrеstimation еrrors arе unЬoundеd, whеrеas undеrеstimation еrrors arе Ьoundеd, sinсе thеy сannot Ье smallеr than zеro. Сonsеquеntly, a graph of a typiсal distriЬution of еstimatеs of thе agе whеn two spесiеs divеrgеd, gathеrеd from a numЬеr of diffеrеnt gеnеs' is skеwеd from thе normal Ьеll shapе, with a largе numЬеr of еstimatеs of youngеr agе сlustеrеd togеthеr at Onе еnd and a long tail of oldеr-agе еstimatеs trailing away toward thе othеr еnd. Thе avеragе of thе еstimatеd timеs thus will сonsistеntly ovеrеstimatе thе truе datе (Figurе 10). Thе ovеrеstimation Ьiаs Ьесotnеs grеatеr whеn thе ratе of molесular

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еvolution is slowеr, t} сrеasingly rеmotе.

Сonсlusion

N4olесular Ьiology еrп thе 1953 disсovеry с сhеmiсal. N4olесular еvolution and makеs muсh dеtail and prесi N4olесular Ьiology unity of lifе in thе nat of еnzymеs and othеr lutionists, Ьy making that wеrе prеviously tionary relationships organisms. As pointеd out еar samе Ьasiс сomponеn

Мolесtt|аr Еuolиtitlп

n a stoсhastiссloсk thе proЬaЬility rt (for ехamplе, a givеn quantity o{ gh dесay' to Ье rеduсеd Ьy half in :urs in thе aсtual amount of сhangе. hastiс сloсk is quitе aссuratе. Thе lutionary сloсk liеs in thе faсt that . Еaсh сloсk ..tiсks'' at a difjеrеnt cf a partiсular gеnе or protеin-Ьut gеnеsor protеins providеs an indе_ y еvents. rnt of vаriation oЬsеrvеd in thе еvo:han is ехpесtеd from a stoсhastiс еrdispеrsеd''' or somеwhat еrratiс. ong diffеrеnt linеagеs arе not еХсеsin prinсiplе, to timе phylogеnеtiс d е s i r е dЬ , u r m o r е g е n е so r p r o t е i n s е еxaminеd than would Ье requirеd Thе avеragеratеs oЬtainеd for sеvrly prесisе сloсk' partiсularly whеn ) n a r yе v е n t si n v t r l v еl o n g t i m е p е r i эngеr). Lrе 9, whiсh plots thе сumulativе rrotеins against thе datеs of divеr_ ings) as dеtеrminеdfrom thе fossil rЬstitutionis fairly uniform. Somе s Ьеlow thе linе at thе lowеr lеft of owеr ratе than thе avеragе for thе Ьесausеthе morе rесеnt thе diverit is that thе сhangеsoЬsеrvеd will г е .A s t h е l е n g t ho f t i m е i n с r е a s е s , ny linеagеarе likеly to сanсеl onе , that molесular timе еstimatеs tеnd i Ьasеd on othеr mеthods and, inris is a сonsеquеnсеof thе statistiсal arе asymmеtriсally distriЬutеd. Bеar diffеrеnсеsbеtwееn two spесiеs But ovеrеstimation еrrors arе un. ; arе boundеd' sinсе thеy сannot Ье h of a typiсal distriЬution of еstiеd, gathеrеdfrom a numЬеr of difЬеll shapе,with a largе numЬеr of hеr at onе еnd and a long tail of thе othеr еnd. Thе avеragе of thе )vеrеstimatеthе truе datе (Figurе rеatеr whеn thе ratе of molесular

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Figurе 9. Ratе сlf nuсiеotidе suЬstitution ovеr palеontologiсal timе. Еaсh сlf thе ]5 dots marks thе timе аt whiсh a pair оf spесiеs divеrgеd from а сOmmon anсеstor (horizoпtаl scаle) and thе numЬеr оf nuсlеotidе suЬstitutions, or protеin сhangеs' that havе oссurrеd sinсе thе divеrgеnсе (uertiсаl sсаlе).Thе solid linе drаwn from thе origin to thе ()utеrmost dot givеs thе avеragе ratе of suЬstitution.(Aftеr Fitсh 1976.)

еvolutionis slowеr, thе sеquеnсеsusеd arе shortеr, and thе timе Ьесomеs inсrеasingiyrеmotе.

Conсlusion Мolесular Ьiology еmеrgеdas a disсiplinе 100 yеars аftеr Darwin' following thе 1953 disсovеry of thе douЬlе-hеliх struсturе of DNA' thе hеrеditary сhеmiсal.Molесular Ьiology providеs thе strongеst еvidеnсе of Ьiologiсal еvolutionand makеs it possiЬlе to rесonstruсt еvolutionary history with as muсh dеtail and prесision as anyonе might want. Molесular Ьiology provеs еvolution in two ways: first, Ьy showing thе unity of lifе in thе naturе of DNA and thе workings of organisms at thе lеvеl of еnzymеsand othеr protеin molесulеs;sесond,and most importаnt for еvolutionists' Ьy making it possiЬlе to rесonstruсt еvolutionary rеlationships that wеrе prеviously unknown, and to сonfirm, rеfinе, and timе all еvolutionary rеlationships from thе univеrsal сommon anсеstor up to all living organisms. As pоintеd out еarliеr in this сhaptеr, all organisms arе madе up of thе samеЬasiс сomponеnts,whiсh, morеovеr' are similarly assеmЬlеdand usеd.

119

150

Мoleсulаr Еuolиtiсln

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organisms, from baсtеr now Ье rесonstruсtеd w Ьiology. Darwin сould r

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Divergenсetime(x100MY) Figurе 10. Skеwingand agе Ьias in еstimatingmolесulardatеs.Тhе insеtshows thе trее topology for linеagеsA, B, and С; t.. and tт rеprеsеnt'rеspесtivеly' сaliЬrationand targеttimеs.Thе mаin panеl shows a fгеquеnсydistriЬutionof 1,000 еstimatеsof thе divеrgеnсеtimе ЬеtwееnlinеagеsС and AB in thе insеt' sеt to havе oссurrеd3 billion yеars ago and оЬtainеdwith thе usе of a short (7.5 rеsiduеs),slow.еvоlving(onеrеplасеmеntpеr sitе pеr 1010yеars)protеin and with thе usе of thе split ЬеtwееnA and B, sеt to 300 million yеarsago' as a сaliЬratiсlnpoint. T and M rеprеsеntaсtual (3 Ьillion yеars)and еstimаtеdmеan (4'084 Ьillion yеars)timеs.(Мodifiеd from Rоdriguеz-Trеllеs еt a|.2002.|

In all organisms' from Ьaсtеria to humans, thе instruсtionsthat guidе thе dеvеlopmеnt and funсtioning of organisms arе еnсasеd in thе samе hеrеditary matеrial, DNA, whiсh providеs thе instruсtions for thе synthеsis of protеins. Thе thousands of divеrsе protеins that еxist in organisms сonsist of thе samе 20 amino aсids in all organisms, from Ьaсtеria to plants and to animals. Thе gеnеtiс сodе, Ьy whiсh thе information сontainеd in thе DNA of thе сеll nuсlеus is passеd on to protеins, is sharеd Ьy all sorts of organisms. All organisms usе similar mеtaЬoliс pathways-sеquеnсеs of Ьioсhеmiсal rеaсtions-to produсе еnеrgy and to makе up thе сеll сomponеnts.Thе unity of lifе rеvеals thе gеnеtiс сontinuity and сommon anсеstry of all organisms. Thе dеgrее of similarity in thе sеquеnсеof nuсlеotidеs in thе DNA (and thus thе sеquеnсеof amino aсids in thе еnсodеd protеins) makеs it possiЬlе to rесonstrцсtеvolutionary history. Еaсh of thе thousands of gеnеsand thousands of protеins prеsеnt in аn organism providеs an indеpеndеnttеst of thе organism's evolutionary history. Thе еvolutiоnary геlationships among all

Avisе,J. С.2004. Мolесu Sundеrland,МA: Sinа A y a l а ,F . J . , е d .1 9 7 6 .М o l B a k е r ,A . J . ' е d .2 0 0 0 .М o Сarroll, S. B. 2О06.Тhе М Rеаlrd of Еuсllutiсlп D i с k е r s o nR , . Е . 1 9 7 1 .T h еvolution.lourпаl of 1 Fеlsеnstеin, l. 2О04.lпfer Fеnсhеl,т. 2002. Thе Оri1 UnivеrsityPrеss. Fitсh,.W.x4. 1976.Molес Еuolutioп,160-.l78. l Fitсh, \V. N4.,and Е. Мarg I55 279-284. Grаur, D., аnd \7.-Н. Li. 2 Sundеrland,MA: Sinа Hаll' B. G.2004. Phуlogе Assосiatеs. Hazеn, R. М. 2005.geи.e DС: JosеphНеnry Prt Lynсh.M. 2007. Тhе orig Assoсiatеs. Nеi, \4.,and S.Kumar.2 Oxford UnivеrsityPrс Rоdriguеz_Trеllеs' F., R. T toward оvеrеstimatio Nаtir.lпаlАсаdеmуof .Woеsе, C. R. 1998.Thе ur SсiепсеsUSА 95: 68.5

МoIеculаr Еuolutioп organisms'froпr baсtеria and protozoа to plаnts, anirnals, and humans сan now bе rесollstruсtеdwith as muсh dеtail as wantеd Ьy mеans of molесular Ьiology.Darwin сould not havе hopеd for morе.

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115

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ime(xl00MY) ng mсllесulardatеs.Thе insеtshows .. and t, rеPrеsеnt'rеspесtivеlv' :Ishowsа frеquеnсydistriЬutionof ,ееnlinеа8еsС and AB irr thе insеt, obtainеdwith thе usе of а short (75 еr sitеpеr 10l0yеars)protеin and еt to 300 million yеarsago' as a (3 Ьillionyеars)and еstimatеdmеаn Rodriguеz-Trеllеs еt al. 2О02'|

s' thе instruсtionsthat guidе thе dеarе еnсasеd in thе samе hеrеditary lсtions for thе synthеsis of protеins. ist iп organismsсonsist of the samе сtегiato plirntsand to animals' Thе ontаinеdin thе DNA of thе сеll nury all sorts of organisrns.All organuеnсеsof Ьioсhеmiсal rеасrtons-ro omponеnts.Thе unity of lifе rеvеals ;tгyof all organisms. се of nuсlеotidеsin thе DNA (and эnсodеdpгotеins)mаkеs it possiЬlе of thе thousandsof gеnеsаnd thoшprovidеsan indеpеndеnttеst of thе olutionary rеlationships among all

Avisе,.|. с. 2004.МolеснlаrМаrkеrs,Nаturаl Нistorу,апd Еuolutiсlп'2nd ed. Sundеrland' N{A:SinаuеrAssoсi21tеs. Ayala,}-.l., еd.|976, МolесиlаrЕuolt,ttirlп, Sundеrland'MA: SinаuеrAssoсiatеs. Bakеr,A. J., еd.2000.МolесulаrМеtЬrldsiп Ессllogу.Oхford: Blaсkwеll. Сarroll,S. B. 2006. Thе Маhiпg of the Fittеst:DNА апd thе UltimаtеForeпslс .!?...W. Rесordof Еuсllutiсlп.Nеw York: Norton. Diсkеrsоn, R. L. 1971.Thе struсturеof сytoсhromес and thе ratеsof molесular еvolution. Jtluпlаlof МolесulаrЕuolutioп|: 2645. MA: SinauеrAssoсiatеs. Fеlsеnstеin, Sundеrland, J.2004, IпfеrriпgPhуlogеniеs, Fеnсhеl,Т.2002, TЬе origitl аnd Еаrlу ЕL,lllutitlпof Lifе, oхford: Oхford Prеss. Univеrsit,v Fitсh,W. I\4.1976.Мolесulаrеvolutiorrary сlсlсks.In F. J. Ayаla.еd.,Мolесulаr Еuolutkln,|60_178, Sundеrland,]r,1A:SinauеrAssoсiatеs. Fitсh,W. М., and Е. Margoliash.1967.Сonstruсtionof phylogеnetiс trееs.Sсiеnсe 155:279-284. of МoleсulаrЕuolutiсtп.2ndеd. Graur,D.' аnd \W.-H.Li. 2000.Fuпdаmeпtсlls }vIA:SinauеrAssoсiatеs. Sundеrlаnd, МA: Sinauеr Hаll,B. G. 2004.PhllogепеtiсТreesМаdе Еilsу.2ndеd. Sundеrland, Assoсi.rtеs. Hazеn,R. N{.2005. gепoеosis:Тhе Sсiепti|icQuest for Li|е's Оrigiп. Washington' DС: Josеphl{еnryPrеss. Lynсh,M. 2ОО7,Thе Оrigiпs of Cепomе Аrchitесturе.Sundеrland,MA: Sinauеr Assoсiatеs. Nеi, М., and S. Krrmar.2000. Мoleсulаr Еuoltltionапd Phуlogепсriсs.oxford: oхford UnivеrsityPrеss. Ьias Rodriguеz-Tтеllеs, F', R, Tarrio,and F. .].Avala.2002.A mеthodologiсal timе sсalеs.Proсееdiпgs of the towardovеrсstimatiоn of molесulаrеvolutionary NаtioпаIАсаdеmуof SсiепсеsUSA 99: 8112-8l15. .!Иoеsе, С. R. l998. Thе univеrsalanсеstor.Proсееdingsof the Nаtiс-lпаlAсаdemу oi USА 95: 6854_6859. Sсiеnсеs

i ),

Еvolution of thе Gеnomе Briаn Сh аrlesluorth аnd Dеborаh СhаrlesшОrth

Сhangеs in thе gеnеtiс information storеd in thе gеnomе arе thе ultimatе Ьasis of еvolution. Мuсh of еvolцtionary Ьiology involvеs studiеs of thе oЬsеrvaЬlе сharaсtеristiсs of organisms and thе hеritaЬlе сhangеs on whiсh thеir еvolution dеpеnds. But gеnomеs thеmsеlvеsalso еvolvе. Thе gеnomеs of сontеmporary spесiеs rеflесt Ьillions of yеars of еvolution, and thеy arе still еvolving, oftеn surprisingly rapidly. Data on gеnomе organization havе Ьееn aссumulating sinсе thе еra of сlassiсal gеnеtiсs, starting with thе disсovеry that gеnеs are сarriеd in thе сhromosomеs of сеlls and сan Ье mappеd gеnеtiсallyand physiсally to spесifiс loсations in thе сhromosomеs. Thе latеr disсovеry that сhromosomеs arе madе of nuсlеiс aсids has lеd to inсrеasingly finе.sсalе physiсal maps of gеnomеs' most rесеntly thе сomplеtе sеquеnсеsof (parts of thе) gеnomеs of (singlе individuals from) inсrеasing numЬеrs of spесiеs, now inсluding sеvеral spесiеs of animals (e.g', С. еlegапs Genomе Sеquеnсing Projесt 1'9991International Human Gеnomе Sеquеnсing Сonsortium 2001; Мousе Gеnomе Sеquеnсing Projeсt 2002; Drosopbilа 12 Gеnomеs Сonsortium 2007) and plants (е.g.,Thе AraЬidop. sis Gеnomе Initiative 2001), as wеll as ovеr 80 Ьaсtеrial spесiеs (Sharp еt al. 2005). Gеnomеs of many morе spесiеs will сеrtainly Ье sеquеnсеd in thе nехt fеw yеars, givеn thе rapid advanсеs Ьеing madе in sеquеnсing tесhnology. This information has gеnеratеd rеnеwеd inrеrеst in gеnomе еvolution, whiсh сan now bе dеsсriЬеd in unprесеdеntеd dеtail, and two major Ьoоks havе rесеntly Ьееn dеvotеd to it (Burt and Trivеrs 20О6;LуnсЬ 2007). !иith suсh еxtеnsivе data in hand, Wе сan hopе to idеntify somе of thе main pro. сеssеs involvеd in gеnomе еvolцtion. Modеls of many of thеsе proсеssеs ехist, and somе gеnеral thеmеs arе сlеar. Gеnomе еvolution oftеn involvеs various opposing forсеs, So that thе organization of thе gеnomе of a givеn spесiеs, or of a givеn gеnomiс rеgion, may dеpеnd оn situations that wеakеn or strеngthеn onе forсе or anothеr. Partiсularly intеrеsting situations arisе whеn thе еvolutionary intеrеsts of individual gеnomе fеaturеs сonfliсt with sеlесtion that асts on thе organisms thеmsеlvеs. Bесausе of thе сomplех IJZ

intегplay of diffеrеnt сrеasе in gеnomе stzе As with othеr typе thе typеs of сh:rrrgе within individuals (rт

matеrial of еvolution сan sprеad through t[ of thе spесiеs.Thеrе l lutionary proсеssеs.I may сausеindividual agе; as wе shall sее,s als is not thе only dе is thе random proсеs nеnts of gеntlmеs thl tions аrе finitе in siz dеtеrministiс fсlrсеs r ovеr gеnеrations, sor taЬlishеd (fixеd)in al trollеd Ьy thе еffесti thе numЬеr of Ьrееd rious variantsсan bе ordеr of thе rесiproс Thе rеlativе nragnitu dirесtion and spееd Ьееn strongly еmphа (2007). Bеforе dеsсriЬing r important fеaturеso tionary faсtors that r

Thе Compositio

тHЕ GЕNЕт|с

Тhе сhеmiсal Ьаsis о is a long strand tlf р linkеd Ьy sugar and 2008). Irr all сеllul сlеotidе is douЬlе-st may Ье douЬlе-stran strandеd DNA (suс fluеnza virus). Thс сoпrplеmеrrtary:wht ninе, thе othеr straг thе сomplеmеntary l thus Ье dеsсriЬеd ir

Еuolиtion of thе Cenomе

Gеnomе d 1

in thе gеnomеarе thе ultimatе Ьaiology involvеs studiеs of thе oЬl thе hеritaЬlе сhangеs on whiсh msе]vеsalso еvolvе. Thе gеnomеs f yеars of еvolution, and thеy arе )ata on gеnomе organization havе сal gеnеtiсs' starting with thе dislromosomеs of сеlls and сan Ье ifiс loсations in thе сhromosomеs. е madе of nuсlеiс aсids has lеd to nomеs' most гесеntly thе сomplеtе i n g l е i n d i v i d u a l sf r o m ) i n с r е a s i n g rl spесiеsof animals (e'g., С. еle.ntеrnational Нuman Gеnomе Sе:nomе Sеquеnсing Projесt 2002; 7) and plants (е.g.,Thе AraЬidop:r 80 Ьaсtеrialspесiеs(Sharp еt al. мill сеrtainly Ье sеquеnсеd in thе ; bеing madе in sеquеnсing tесh' .еd intеrеst in gеnomе еvolution' :ntеddеtail, and two major Ьooks Trivеrs 2006;Lупсh 2007). \Хlith t o i d е n t i f ys o m е o f t h е m a i n p r o Lеlsof mаny of thеsеproсеssеsехGеnomе еvolution oftеn involvеs nization of thе gеnomе of a givеn dеpеnd on situations that wеakеn сularly intеrеsting situations arisе lual gеnomе fеaturеs сonfliсt with msеlvеs.Bесausе of thе сomplеx

intеrplayof diffеrеnt forсеs' сhangеs oftеn oссur in onе dirесtion (е.g.,аn inсrеasеin Е]еnomеsizе) and thеn latеr rеvеrse. As with othеr typеs of еvolutionary сhangе, wе nееd to undеrstand Ьoth thе typеs of сhangеs in gеnomе оrgаnization and сomposition thаt arisе within individuals (mutations and othеr molесular сhangеs that arе thе raw matеrialof еvolution) and alsсl how a trait сarriеd initially Ьy onе individuаl сan sprеadthrough thе wholе population, lеading to еvolution of thе gеnomе of thе spесiеs.Thеrе arе tWO main сausеsof this sprеаd, just as for othеr еvolutionaryproсеssеs.First, dеtеrnrinistiсforсеs, partiсularly natural sеlесtion, may сausе individuals with a givеn trаit to lеavе morе dеsсеndantsthan avеrаgе;as wе shаll sее,suсh Daгwinian natuгal sеlесtionat thе lеvеl of individuals is not thе only dеtеrministiсforсе that aсts on gеnomеs.A sесond faсtor is thе random proсеss of gепеtiс drift, wЬicЬ is еspесially rеlеvant for сomponеnts of gеn()mеsthat do not affесt orgаnismal funсtions. Bесausе populations arе finitе in sizе, gеnеtiс variants that arе suЬjесt to suffiсiеntlywеak dеtеrministiсforсеs will ехpеriеnсе random fluсtuations in thеir frеquеnсiеs ovеr gеnеrations,somеtimеs сausing an initially rarе vаriant to Ьесomе еstaЬlishеd(fiхеd)in all individuals of a spесiеs.Thе ratе of gеnеtiсdrift is сontroliеd Ьy thе еffесtiuе poplilаtioп siee, whiсh is usually muсh smallеr than thе nunrЬеrof Ьrееding individuals in a spесiеs(Kimura 1983). Еvеn dеlеtе. rious variаnts сan Ьесomе fiхеd Ьy drift if thе intеnsity of sеlесtion is of thе ordеr of thе rесi;lrсlсalof tЬе еffесtivеpopulation sizе or lеss (Kimura 1983). Тhе rеlativеmagnitudеsof drift and dеtеrministiсforсеs thеrеforесontrol thе dirесtion and spееd of еvolutionary сhangеs irr gеnomеs; this hаs rесеntly Ьееn strongly еmphasizеd as а сausal faсtor in gеnomе еvolution Ьy l,ynсh

(2007).

Bеforе dеsсriЬing ехamplеs of hypothеsеsаnd tеsts,wе first outlinе somе important fеaturеstlf gеnolте orgаnization аnd sizе and thеn disсuss еvolutionary faсtors that may havе sЬapеd thеsеpropеrtiеs.

Thе Сomposition and Sizе of thе Gеnomе тHЕ GЕNЕт|с MAтЕR|AL Thе сhеmiсal Ьasis
15З

154

Еuolutioп of thе Geпomе (A, T' G, and С), whilе that of thе douЬlе strцсfurе is spесifiеd Ьy thе frе. quеnсiеs of the Ьasе pairs AТ and GС. RNA is gеnеrally single strandеd, with a diffеrеnt sugar rеsiduе from that in DNA and with uraсil Ьasеs instеad of thyminеs' Although thе origins of thе gеnеtiс сodе arе unknown' sеlf-rеpliсatirrg RNA molесulеs may havе Ьееn thе еarliеst form of ..lifе,'' Ьut thе transition to gеnomеs that usеd thе muсh morе stablе DNA oссurrеd long ago (Joyсе 1989). DoцЬlе-strandеdDNA also allows damagе to Ье сoгrесtеdЬy сopying from thе undamagеd сomplеmеntаry strand. Sinсе DNA largеly laсks RNAs ability to aсt as a сatalyst, this сhangе must havе gonе along with thе еvolution of a mеans of transсriЬing onе stгand of a gеnе's DNA into RNA. In prеsеnt-dayorganisms thе sеquеnсеof basеs in thе ..mеssеngеr''RNA tгansсriЬеd from a gеnе dеtеrminеsthе sеquеnсеof thе amino aсids in thе protеin сhain еnсodеd Ьy thе gеnе (Figurе 1). Thеrе arе also many RNA molесulеsof dirесt funсtional signifiсanсе, whiсh аrе transсriЬеd (сopiеd) frоm DNA Ьut not translatеd into an аmino-aсid sеquеnсе.

vlгus gеnomеs arе usuz fluеnza) paсkagе sеvеrс into tlrе samе viгus pal have diffеrеnt RNAs pa thus сomЬinе diffеrеnt ing multiplе infесtions, F{uпrаns and otlrеr а isms Ьеlong to thе еuki DNA organizеd into l сеlls (Figurе I). Тhе с dеal with thе proЬlеm с сulеs, and сепtromеrеs sion to thе daugЬtеr се еukaryotеs, suсh as thе gеnoп1е,with just onе с matе' thеге is а Ьriеf d еaсh mating partrrеr.Tl

oRGANlzAт|oN oF тHЕ GЕNЕт|с MAтЕR|AL Мany prokaryotеs' gеnomеs (Ьaсtегia and virusеs) сonsist of just a singlе DNA or RNA n-rolесulе,oftеn сirсtrlar (TaЬlе 1). Somе Ьaсtеriа (suсh as Borelliа, thе сausе of Lymе disеasе)lravе sеvеral sеParatе molесulеs; although

Сhromosome

Genes messenger RNA intron

telomerе

а.

f"

I сenтromere

telomere

Ц г F FI

t

'i',,

spIiсеd MRNA

+lЕ

Protein

trans|аtion

-+

T а Ь l е l . G е n о m еs i z е s orgаnism Virusеs Plаnt viroids Influегlzavirus Rеovirus Phagе tpX174 SV4O Vaссitriavirus Baсtеria Е. сoli Му сo1llаsmа gепitаlium

intron i

i ntron

+#

Figurе 1' Chromosomеs,showingthеir major fеаturеsand thе Ьandingpаttеrns that сan Ье sееnwith stаiningmеthods.Thе figurеаlso shows a sсhеmatiсof a rеgion of thе сhromosomе сontaining thrее gеnеs'thе mеssеngеrRNA produсеd Ьy thеm, and thе individuaIprotеinsеnсodеdby thе mеssеngеrRNA.

Nuсlеurrgеnomеsоf еtrk Y east (Sаcchаro|l,t)) L:еsсе Nеmatodе (Саепorhаbd Fruit fly (Drosophilа mе Ftsh (Fugu rubripеs) Sаlаmandеr Mat-lrmal (Homo sа|liеп Сress (Arаbido1l sis thаlit Mаizе (Zeа mауs) Fritillа11'p ritillаriа,lssу

Ntlrс: AЬЬrеviаtions:Ьp kiloЬаsеs;МЬ, mеgаЬasеs ? mеаns thаt thе gеnеnu ? ? t h . r ri t i s b а s е do т l i n . lаr
Еuolutiсlпof tbе Gепome эlе stгuсturе is spесifiеd Ьy thе frе,IA is gеnеrallysirrglеstrandеd,with 'trAand with uraсil Ьasеs instеad of ]odе arе unknown, sеlf-rеpliсating :st form of ..lifе,'' Ьut thе transition Ьlе DNA oссurrеd long ago (Joyсе i damagеto Ье сorrесtеdЬy сoрying nd. Sinсе DNA largely laсks RNA's Jst havе gonе along with thе еvolund of a gеnе's DNA into RNA. In lsеs in fhе ..mеssеngеr''RNA tranrсеof thе amino aсids in thе protеin rе arе also many RNA molесulеs of ransсribеd(сopied)from DNA Ьut эе.

virus gеnomеs aге trsually singlе nrolесulеs,somе RNA virusеs (suсlr as influеnza)paсkagе sеvеrаl diffеrеrrtRNA rrrolесulеsthat саrц, diffегеIltgеnеs into thе samе virus partiсlе. Otlrеr RNA virusеs (е.g.,alfalfa rr-rosaiсvirus) havеdiffеrеntRNAs paсkagеd into sеparatеvirus partiсlеs.Thеsе virusеsсan thus сomЬinе diffеrеnt portions of thеir gеnomе from diffеrеnt parеnts during multiplе infесtions,a primitivе typе of sеxualitY. Humans and othеr аnimals, plants, fungi, and man,v singlе_сеllеdor!]anisms Ьеlong to гhе еukaryotе division of lifе' whiсh is dеfinеd Ьv hаving thе DNA organizеd into linеar сhromosomеs сarriеd within thе rrLrсlеiinsidе сеlls (F.igurе1). Thе сhromos
lс мAтЕRIAL nd virusеs)сonsist of just a singlе (TaЬlе 1). Somе baсtеria (suсh as lеvеralsеpаratеmolесulеs; although

spIiсed MRNA

Protein

translation

.+|Е

+

+# lr fеaturеsand thе Ьanding pattеrns figurеalso shows a sсhеmаtiсof a gеnеs'the mеssеngеr RNA produсеd d Ьy thе mеssеr-rgеr RNA.

TaЬlе1. Gеnorrrеsizеs Organism Virusеs Plant viroiсls Influеnzavirus Rеovirus Phagе
Gеnomе

Gеnе numЬеr

('еnomе sizе

0 12 22 11 6 .100

З00Ьp l 3 . . 5k Ь 2зkb 5 . 4k Ь

Vaссiniaviгus

ssRNA ssRNA dsRNA ssDNA dsDNA dsDNA

Baсtеria Е, сoli МусoplаsmаgепitаIium

dsDNA dsDNA

4,400 500

4 . 6М Ь 0 . 6М Ь

sv40

Nuсlеаrgеnomеsof еukaryotеs Y еast(Sассbаro1п)| сеs cеrеuisiае) Nеmаtodе1Саепсlrhаhditisеlеgап,s) Fruit fly (Drosrlph ilа melапсlgаstеr) FisЬ (Fugи rubripes) Salamandеr Mammal (Homсl sаpiеns) Сr ess(Аrаb i dopsi s th аliапа) Мaizе (Zеа lttаvs) Fritillary (F ritil lаriа аs sуriаcа)

6,000 19,000 14,000 22,000(?) 3 0 , 0 0 0( ? ? ) 2 0 , 0 0 0( ? ) 27,000 .r0,000(??) 2 7 , 0 0 0( ? ? l

)

Кl]

187kЬ

12Мb 100МЬ 1 4 0М Ь 400MЬ 90,000МЬ 3,000МЬ 1 0 0М b .i,000МЬ MЬ L20,000

Nofe: AЬЬrеviations:bp, basеpаirs;ss, singlestrаndеd;ds, douЬlс strаndеd;kb, kilоbasеs; МЬ' mеgаЬasеs. ? mеаnsthаt thе gеnе numbеr is сlnll' аpproximatеlyknоlvn froпr thе gсnolrrеsеqllеnсс' gсlltlt-t-tеs ?? that it is Ьasеdoгrinсompletссvidеrrсеor analсlgуrvitЬ sеquеnсесl
].i.i

1.'6

Еuolutirп of tbе Gепomе to rеstorе thе haploid statе.In this division' gеl1еsfrom thе Parеntal сеlls аrе rесOmЬinеdthrough rесiproсal еxсhangеsof poгtions of thеir сhromosomеs (crossiпg ouеr: SеeLеwin 2008 аnd Figurе 2). In animаls and highеr plants thе diploid stagеprеdominatеs,аnd thе haploid sti.ltеis oftеn just a Ьriеf part oI rhе rеprсlduсtivеproсеss' Chromosomе numЬеrs in thе haploid sеt vary widеly among diffеrеnt spесiеs:16 in thе сasе of Сhlаmуdomoпаs,5 in Drosophilа,2З in humans, but somеtimеs just a singlе сhromosomе (in a spесiеsof ant and an Аsссtris roundworm). Сharrgеs Ьеtwееn spесiеs in сhгomosomal stгuсturе arе сommon, involvtng dtlpliсаtion.sаnd dеIеtit.llts of gеnetiс matеrial, inuеrsioпsof parts of сhromosomеs (Figurе 3), and trапslocаtiсlпs(ехсhangеsof matеrial Ьеtwееn diffеrеnt сhromosomеs). Сhromosomе rеarrangеmеnts oссur infrеquеntly in еvolution (roughly onе pеr gеnomе pеr 10 million yеars in mammals, although somе gгoups, suсh аs rodеnts, havе rаtеs 10 timеs highеr: Еiсhlеr and Sаr-rkoff2003). Ovеr еvolutionary timе) tlrе rlrdеr of gеnеswithin a сhromosomе gradually Ьесomеs sсramblеd Ьy suссеssivе invегsions. Sеvеrаl human сhromosotnеs sееm to havе rеmainеd unсhanяеd in gеrrе сontеnt

Сrossingover

f

\

Figurе 3. A сlrromсlsomt сhromosomе, and thе aр Ьееn rеаrrangеdso that othеr way аrttund from

ABсD

PаrentaI сhromosome

(though not ordеr) ovе m a d е u p < l fs е p a r a r еЬ l

сoD|NG AND N

U n e q u a |с ro s s ingo v еr bet wеendup|iсated or rеpeatedgеnеs

I

Y

Figurе 2. Тop: Сrossing ovеr in a rеgion of a сhгomosomе сontaining fivе gеnеs, A to Е, shсlwing thе rеsulting rесomЬinant сombinations of thе gеnеs (indiсatеd Ьy uppеr. and lowеrсasе lеttеrs аnd аlso Ьy Ьlасk аrrd grаy linеs for tlrе twсl diffеrеnr parеlrtal сЬromosonrеs). Bottom: Сrсlssing ovеr in a геgion rrf сhromosomе сontaining two dupliсatеd gеnеs that аrе similar еnor.rghthat thеy may mispair, lеading тo unеqual сrossing ovеr.

Gеnomе sizе is dеfinе loid gеnomе. A gеnom а r е t r а n s с r i Ь е di n r o m t quеnсеs (Lеwin 2008 qиепсes ar'd iпtroпs.h transсriЬеd but arе rеr latеd; in еukаryotеs,ir |л as thе spliсе
Еuolutioп of tbe Genomе )n' gеllеsfrom thе paгеntal сеlls arе s of portions of thеir сhromosоmеs r e 2 ) . I n a n i m a l sa n d h i g h е r p l a n t s aploid statеis oftеn just a Ьriеf part

I Ц

invertеd rеgion

l-

l sеt vary widеly among diffеrеnt зs, .5in Drosopbilа,23 in humans, (in a spесiеsof ant and an Аsсаris n сhromosomal struсturе arе сomls of gеnеtiс matеriаl, iпuеrsiсlпs of lпsloсаtioпs(ехсhangеsof matеria] osomе fеarrangеmеnts oссur infrе-

I

nе pеr 10 miiliorr уеaгs in mamrnals, havе гаtеs 10 tiпrеs highеr: Еiсhlеr lе' thе ordеr of gеnеswithin a сhroЬy suссеssivеinvеrsions. Sеvеral rainеd unсhangеd in Е]enесontеnt

lr

!

I

I

non-invertеdregion

-

l. ffi

!

,l

Figurе 3. A сhrtlnlosomе invеrsion. Thе diagram shorvs thе Ьаnding pattеrn of a сhromosomе, and tЬе appеaranсе whеn thе top pаrt of thе сhromosomе has Ьеегlrеarrangеd so that part Of thе gеtrorте in thе гight-hand сhromosomе is thе othеr Way around from thе orсlеr in thе lеft сlnе.

\ \

ff,H,i;:il' t:i

I

ParentаI сhromosome

_/

(thoughnot ordеr) ovег thе сoursе of somе 70 million yеars, Ьut othеrs arе madе up of sеparatеЬloсks dеrivеd from diffеrеnt atrсеstralсhromosomеs. сoDING AND NoNсoDING sЕauЕNсЕs

up|iсated or repеatedgenes -

Wж3Е-

жWE

сlrromosomе сontaining fivе gеnеs, lmbinations of thе gеnеs (indiсatеd llaсk and gray linеs f
Gеnomе sizе is dеfinеd as thе numЬеr of Ьasеs in a singlе strand of thе haploid gеnomе.A gеnomе has two main сomponеnts:сoding sеquеnсеs(whiсh arе transсriЬеdinto mеssеngеrRNA and еnсodе protеins) and nonсoding sеquеnсеs (Lеwin 2008). Nonсodirrg sеquеnсеs inсludе Ьoth intеrgеllic sе. quеnсes and iпtrсlпs' Introns arе sеgmеnts of sеquеnсеswithin gеnеs that arе transсriЬеd Ьut aге rеmovеd Ьу spliсiпg Ьеforе tlrе mеssеngеr RNA is translatеd;in еukaryotеs,intron spliсing involvеs a protеin.RNA maсhinе known as tЬe splicеosorпе' Intеrgеniс sеqllеnсеs and somе introns inсludе rеgions thаt aге rеsponsiblеfor сontrolling gе11е еxpгеssionby dеtеrmining thе lеvеls rrrеssеngеr produсtion timing of RNA fronr rrеarbygеnеs.Thеsе arе nonаnd с o d i n gЬ u t f u r l с t i o n a lp a r r s o [ g е n о m е s . Еvеn with сomplеtе gеnomе sеquеnсеs'it is diffiсult to сount a gеnomе's gеnеsЬесausесoding sеquеnсеsarе almost indistinguishaЬlеfrom othеr sеproЬlепr Ьесausеof thе low proquеnсеs.Thе task is a nееdlе-in-tЬе-haystaсk poгtiоn сlf сoding sеquеnсеsin thе gеnomеsof man1.nrultiсеllr"rlаr orgаnisms

157

158

Еuolutiсlltrlf thе Сепolltt, (еstimаtеd to Ье aЬout 1.5% of hunran DNA; sее Intег11i1tional Human Gеnomе Sеquеnсing Сonsortium 2001). Thе triplеt gеnеtiс сodе usеd Ьу mеssеngеrRNA, ilr whiсЬ thгее ad jaсеnt nuсlесrtidеs(сodoпs)сorrеspond to еaсh amino rrсid of thе prсltеirr еnсodеd' and сеrtain triplеts-rhе sfoдr сodсlпs-stgnify tЬе еrrd of traIlslation,сan sllggеstсandidаtеsfor sеquеtlсеs thаt еnссldеamino асid sеquеrrсеs.Thе rrrrсlеotidеsin thе third pсlsitionsof many сodons do not аffесt thе aпrino aсid еnсodеd, sitrсе sеvеral diffеrеnt сodons сihatеroсЬromаtiп'tlrе Ьloсks ot unrtsuallу dееply staining matеriаl visiЬlе in dividing сеlls' сhromosomеst usually сonсеntratеd nеar thеir сеntl:olтlеrеsаnсl (in somе spесiеs)tеlomегеs (Jtlhn and Мiklos 1988; Еlgin and Grеwаl 200з). Tlrеy сltn rnakе up astonishirrg amounts of thе DNA o[ somе
thе fruit fLуDrosсlphilа mеL tеrminаtion) has aЬout 20 r thеm сomposеd of a bloсl.

sparsеr in hеtеroсhromatin Thе amount and sеquеnсе among diffеrеnt spесiеs.Fo madе up of fouг short sa1 thosе оf its distant rеlаtivе, gеnomе sizе (John and Mi

2007 ). Diffеrеnt kangaroo faсtor of 1.6 |a rangе similа of diffеrеnсеs in thе alnoun V a r i a t i o n a m o n g s p е с i е si n largе diffеrеnсеs in gеnom( nttmЬеrs (С:rvaliеr-Smitlr1

Traпsposаblе elemеnts SцЬstantial proportions of p е a t s ( 2 0 0 b а s е s - 1 0k i l o Ь a wholе gеnomе than sаtеlli ttble еlemeпrs (TЕs)' whiсh сations in thе gеnomе (/r worm Саеnorbаbditis еle5 .s-10% of tlrе total gеnom humans thе figurе is about Сonsortium 2001)' and st aЬundanсеs (Lynсh and Сс Sеvегal nrajor typеs of T of organisms (TaЬlе 2); Within еaсh of thе nlajor сlassifiеd into diffеrеnt farт ilar. Unlikе thе othеr typе lеast somе mеmЬеrs with (

for thеir transposition' Ьu mutations in thеir sеquеn еnсе of сomplеtе еlеmеnt othеrs arе frаgtnеnts who human gеnomе is madе u; Just as with satеllitеsес latеd spесiеs сan Ье duе t

without major diffеrеnсе split from its rеlativе D. aЬout thrее timеs as man amounts of thеsе sеquеnс аnd onе diрloid riсеspесi thе nrultipliсation of a fеv

Еuolution of the cenome n DNA; sее Intеrrrаtional Нtrtnan . Thе triplеt gеnеtiс сodе usеd Ьy nuсlеotidеs(сodспs) сorrеsponсlto еd, aIrсl сеrfаin triplеts-thе srop ]n suggеstсаndidаtеsfor sеquеnсеs ruсiеotidеsin thе third pсlsitions of сid еnсodеd,sinсе sеvеral diffеrеnt id (thе сodс is dcgепеrаte)(Lvnсlr tvеngеnomеrеgion is сomparеd Ье_ lf diftЪrеnсеs at еvеry third position ng sеquеnсеsno suсh pattеrn will nutnЬеrsrеmain unсеrtain for tlrе гhеsееstimatеsarе сonstantly bеing .ganisпlsdiffеr widеly Ьoth in thе l and in thе amottnt of еасh ty-pеof tе t-tt-lntЬеrs gеrrеrllllyсorrеIatеwith amollnt of intеrgеrriсDNA (L1,nсh l gеnomеsof prokaryotеshavе vегy thеy laсk spliсеosomirlintrons' аlгеrrttptеdЬy rnсlЬilеsеquеnсеsthаt ( L е w i n2 0 0 8 ) .U n i с е l l u l а rе u k а r y ' havе gеnеswith fеw, small introns largеstgеnomеsof еukaryotеstеnd iс DNA (L1.nсhаnсl Сonеrr' ?00З;

!сoDING RЕGIoNs h as prсlmotеrsand еnhanсеrs in_ Lеwin 2008), nоnс<;dingrеgions of lеsslikеly to havе important funсypеs thаt oссur rеpе:1tеdlyin tЬе lwo 11lаl()г сomponеllts of gеrrсlt-trеs эsсriЬеothеr typеs оf rеpеats,suсh ' Сharlеsworthеt аl. |994).

rraYs of highly rеpеatеd,nontran; vaгy in lеngth frorn fivе to sеvеral . i с hi n t Ь е Ь a s е s A and T. Satеllitе roсhromаtiп,tlrе Ьl
thе fruit f|у Drosrryhilа melапogаster (thе X chromosotttе, inуolrvedin sеx dе. tеrmination)has aЬout 20 million Ьasеs (MЬ) of satеllitеDNA, aЬout half of thеm сomposеd of a bloсk of rеpеatеd 359 Ьp units. Funсtional gеnеs arе sparsеrin hеtеroсЬromatinthan in thе rеst of thе gеnonre(tЬe eиchromаtiп)' Thе amount and sеquеnсесompositiorr of satеllitе DNA may vary widеly amongdiffеrеntspесiеs.For instanсе,aЬout 4О"Ь of thе DNA of D. uirilis is mаdе up of fotrr short satеllitе sеquеnсеs'whiсh arе quitе diffеrеnt from thosеof its distant rеIativеD. mеlапogаsterzlndсontriЬutе to its muсh largеr gеnomеsizе (Jolrn and Мiklсls 1988; Drosс,rphilа12 Gеn
I5e

1 6 0 Еuolиtiсlп of t|lе Gепсппe TaЬlе 2. TЕ сontеnts оf human and Drсlso1lhlia gеr.roп.rеs TЕs in thе hurтan and D. mclашlgаstеr еuсhromatiс gсnOmсs

Typ"

NumЬсrof сoplсs

Nuп-rЬеr of familiеs

Huпrаns l-ТR еlеmеnts StNЕs LINЕs DNA еlеmеnts

443x10r 1 , 5 . 5xU 1 0 r 8 6 8x 1 0 ' 294x10t

100 3 3 60

682 486 404

49 27 20

D. mеlапogаstеr LТR еlеmеnts LINЕs DNA еlсmсnts

7. of thе gеnomе 8 l-)

z0

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/-.b J

0.97 0.З.'

[пtеrnаtiсlnirl Humаn GеnсlnrеSequеnсingСonstlrtium Sсlurсcs:Humаn dаt:rfrсln.r (200l); Drсlsсlphilir сlаtаirom Kaminkеr еt аl. (2002). (еlеmеntswith rеpеatеd Аbbrеuiаtiсlпs:LТIt сIсrrlсnts,[-сlngTсrmrnirl Rсpеat с|сп.rеrrts rсvеrsсtrаnsсrip. sсqLlсIlссs at сaс|-r сnd, iri thс sаrтlссlriсntatiсln, whiсh rсpliсаtсtl-rrсlrrgh tiсln intсlDNA сlf аn RNA ссlpyof thеir DNA sеquепсе); SINЕs, SЬtlrtIпtеrspеrsесi (еlеrrrеlrts<.500Ьp Nuсlе:rrЕlеt-nеrits 1ong,whiсh rеpliсаtеthrotrglrаn RNA intеrmеdiаtе Ьut lасk rеpеаts:1ndrеli, оn LINЕs to prоvidе thе еt-tzyпrе nееdеdfor thеir rеvеrsеtrаnsсгiptiоn);I-lNЁ, l-оrrglntеrspеrsеdNrrсlеarЕlеmеnts(similаrto LТR еlеmеnts,Ьut > lkb long аr-rdlaсking thе tеrnrir-rаl rеpеаts);DNA еlеmеrrts(еlеmеntsthat rеpliсatе withtlr:tusе сlf аn RNA lntеrmеdiatе, rrsuаllywith shсlrtinvеrtесlrеpеаtsat еaсh еnd).

Most TЕs arе found in intеrgеniсDNA оr (to a lеssеrеХtеnt)in introns. In stlmе rеgions of thе gеnomе' ТЕs саn Ье vеry dеnsеly paсkеd, with multiplе еlеmеnts insеrtеd witЬin onе anothеr. Thе portion of thе D. mеlапogаstеr lrеtеroсhromatinthat irdjoinsthе еuсhromatin is largеly mаdе up of matеrial dеrivеd fronr TЕs (John and Мiklos 1988); thе rеgions around thе сеntromеrеs of А. thаliап.l сhrom()somеs(!7right еt al.200З) and many intеrgеniс rеgions in maizе (SanMiguеl еt al. 1996) arе sirтilar. GЕNoМЕ ADD|т|oNs Еarly gеnornеsmust havе Ьееn vеrv small, Ьut today's organisms havе largе nunrЬеrs of gеnеs with divеrsе funсtions. An important' though infrеquеnt, proсеss is addition сlf gеnomеsor Е]еnеsfrom othеr organisms. Baсtегiа геgularly асquirе novеl gеnеs fr
(Ьluе-grееnalgaе)and pro| mitoсhondria еvolvеd mu. protеoЬaсtеria (Graу 1999 Latеr еndosymЬiont еvе zoa (ma|aria parasitеs and dеrivеd from rеd a.lgaе;prt

МеmЬеrs of thе сhrоmop} сhlоroplast, whiсh has rе сеll. As wеll as thеir plasti still havе a vеstigial nuсlеa ovеr 40O gеnеs)and thus and thе truе nuсlеar gеno

GENЕ DUPLlсAтlс

N{orе frеquеntly, inсrеas Nеw gеnеs arisе from d gеnomеs (Еiсhlеr and Sar сan oftеn Ье rесognizеd tioпs с|ose to thеir progе suсh arrays сan thеn сhal Ьеtwееn two diffеrеnt mе сopiеs of thе sеquеnсеan Somе dupliсatеd array vorеd largе amounts of l gеnеS that еnсodе thе Rl nism (riЬosomеs) and t} gеnеs (Ranson еt al. 200 vantagе' so that natural s pliсatеd gеnеs. Givеn еn< onе of thе dupliсatе gеn Onсе a dupliсatеd gеnе l it and Ье fixеd in thе pс protеin-сoding aЬility Ьу rеmnant psеudogепе'.еvt or part of it. Nеwly dt quiсkly lost from gеnoп сatеs mеans that' aftеr a tinguish from Partial du gеnomе is rесognizaЬly d s е q u е n с еd а t a t h a t p r o v i tеnt, dupliсatе rеgionsсс thе strеtсhеs havе rеturr mеnts will, howеvеr' еvс Somеtimеs, howеvеr, t Ьеforе inaсtivating mutа

Еuolutioп of the Gепome cphiIа gеnonеs .-rсhronratiс!]еn()Пlеs

Numbеr of fаmiliеs

r00 З з 60 49 27 20

,%

of tЬe gеnomе

8 13

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2.65 0.97 0.З.'

umаn (lепсlt.t-tе Sсс1uеI-rсing Соnsсlrti um

(2002).

l l R е p е а t с I е m е n t s ( е l е п r с l r t sw i t h r е р е а t c d . w h i с h г с р | i с l r еt h r r ' u н h г ( v е r \ ( .t r ; l I t s с r i р s с q u е n с с ) ;S I N Е s ' S h t l r t I п t е r s p е r s е с l : h r е p l i с а t е t h r с l t r g hа n R N A i n t е r r r l с d i а t е thе еnz1'mе nееdеd for thеtr геvеrsс tгanl е m с n t s ( s i r n i I а rt о L T R е l е r - n е n t sl,l u t ) N A с l е m е n t s ( е | е l n е п t st l r a t г е p l i с а t с vith short invеrtсd rеpеats аt еaсh еnd).

A or (to a lеssеrехtеnt)in introns. In е vеr,vdеnsеlvpасkеd, with rnultiplе rhе portion of thе D. mеlапogаster lmatin is iargеlv mаdе up of matеrial 1 9 8 8 ) ;t h е r е g i o n s a r o u n d t h е с е n \X/rightеt al. 2003) and many intеr1 9 9 6 ) a r еs i m i l а г .

rll, but today's orgаnisms havе largе s. An irrrportant'tЬough infrеqttеnt, rom othег orgаnisms.Baсtеriirrеgu: t е r i a sl p е с i е s( o с h m а n е t a l . 2 0 0 0 ) . i-rеirown gеnoпlеs'as wе]l as thе nulgaеhаvе сhloroplasts,and геd аlgaе lls Ьoth сontаin mitoсhсlndriа (Lvnсh е of prokaryorеtlrigin :rnd arosе еarly tеriаl сеll was еngulfеd into a еukaryn еr-rdosymЬiont. sеqtlеl1сеsof gеnеs tosеof photosynthеtiссyanoЬaсtеria

(bluе.grееnalgzrе)and proЬaЬly еvolvеd around 800 million yеаrs ago, whilе mitoсhondria еvolvеd muсh еarliеr from a group of Ьaсtеria known as сprotеoЬaсtеria(Gгay 1'999). Lаtеr еndosymЬiont еvеnts havе also oссurrеd. Thе apiсomplеxan рrotozoa (malaria parasitеsand thеir rеlаtivеs)and dinоflаgеllatеsсontain plastids dеrivеdfrom rеd algaе;prеsumаЬly a protozoаn сеll еngulfеd a rеd algal сеll. МеmЬеrs of thе сhromophytе group of algaе also сontain a rеd-algal-dеrivеd сhloroplast, whiсh has rесеntly Ьееn shown to rеprеsеl.lta wholе rеd algal сеll.As wеll as thеir plastid gеnomе, mеmЬеrs of thе сryptomonаd suЬgroup still havе a vеstigial nuсlеar gеnomе dеrivеd from thе rеd algal anсеstor (with ovеr 400 gеnеs)arrd thus possеssfour gеnomеs. inсluding thе mitoсhondriа and thе truе nuсlеar gеnomе (Douglas еt аl. 2001). GENE DUPL|сAтIoN AND GЕNЕ Loss Мorе frеquеntly, inсrеasеsin gеnе numЬеrs сomе fronr gеnе dupliсations. Nеw gеnеs arisе from dupliсations of parts of thе gеnomе or of wholе gеnomеs(Еiсhlеr and Sankoff 2003; Lynсh 2007). Singlе gеnе dupliсations сan oftеn Ье rесognizеd Ьесausе thеy fгеquеntly oссur as tаndеm duplicаtioпs с|ose to thеir progеnitor gеnе (Baumgartеn еt al. 2003). Thе sizеs of suсh arrays саn thеn сhangе furthеr Ьy unеqual сrossing ovеr. An ехсhangе Ьеtwееntwo diffеrеnt rnеmЬеrs of an array сrеаtеs onе dеsсеndant with thrее сopiеsоf thе sеquеnсеand onе with a singlе сopy (sееFigurе 2). Somе dupliсatеd arrays of gеnеs proЬаbly еvolvеd undеr sеlесtion that favorеd largе amounts of thе gеnе prodttсt' for ехamplе' thе largе arrays of gеnеsthat еnсodе thе RNA сomponеnts of thе protеin translation mесhanism (riЬosomеs) and thе еxpandеd aггays of sonrе insесtiсidе-rеsistаnсе gеnеs (Ranson еt al' 2002). Oftеn, howеver, highеr gеrrе dosagе has no advantagе'so that natural sеlесtionwill not aсt to prеsеrvеthе funсtions of dupliсatеdgеnеs.Givеn еnough еvolutionary timе, an inaсtivе mutant сopy of onе of thе dupliсatе gеnеs may Ьесomе fixеd in thе spесiеs Ьy gеnеtiс drift. onсе a dupliсatеd gеnе has lost its funсtion, fLrrthеrmutations may oссuг ln it and Ье fixеd in thе population Ьy drift. Еvеntuаlly thе gеnе may losе its protеin-сodingaЬility Ьy mutations сrеating сodons' and it thеn Ьесomеs a rеmnant pseиdсlgeпе;еvеntually delеtions оf gеnеtiс nlаtеrial mаy rеnrovе all or part of it. Nеwly dupliсatеd gеnеs arе thеrеforе oftеn ехpесtеd to Ье quiсkly lost fronr gеnomеs (Walsh 1995; Lynсh 2О07). Loss of gеnе dupliсatеSmеans that' aftеr a timе' wholе gеnomе dupliсations arе diffiсult to distinguish from partial dupliсations; in еithеr situаtion only a fraсtion of thе gеnomеis rесognizаЬly dupliсatеd (IJ7onget a|.2002). \Х/ithсornplеtе gеnomе sеquеnсеdata that providе largе gеnomе strеtсhеsof сlеarly similar gеnе сon. tеnt,dupliсatе rеgions саlr Ье rесognizеd,еvеn whеn most of thе gеnеswithin thе strеtсhеs hаvе returnеd to thе singlе-сopy statе. Chromosomе геarrangеmеntswill, howеvеr, еvеntuallyеrasе all traсеs of dupliсation. Somеtimеs' howеvеr' dupliсatеd gеnеs may gain nеrv funсtions Ьy mr-rtation Ьеforе inaсtivating mutations oссur. For instаnсе, an еnzymе that сatalyzes a

161

162

Еuolиtiсllt

tlf thе (}епсllllе

givеn rеасti
Although it is not knс trollеd, sеvеral gеnomе fеi Ьination ratе. Oпе suсh a of thе frеquеnсy of GС v, man gеnomе thе mеan Gl giоnally from aЬout 30o% Сonsortium 2001).Thе (

с o n с o r d а n t l y Ь е t w е е nr е g morе AT riсh than сodin; tions (whеrе m()st mutatl latеs to somе ехtеnt with tl sеquеnсеs'suсh as psеtrdо tiсularly intеrеstingЬесau Ьесausе of thе input of nrt rhе faсt that thеrе is oftеn (Lynсh 2007\. In thе hum tеnt is highеst for suсh sitt high (lntеrnational Hurnz

and Piganеaо2О02), Anothеr сorrеlatе of rес in high-гесomЬination rе1 Human Gеnomе Sеquеnс А. thаliапа (ltltеrnаtitln \й/rightеt al. 2003) gеnе . 8апs t|7eopposirе is foulrс TransposaЬlе-еlеmеnt.

D r o sop h ilа low-rесomЬiп sеrtions than high-rесom havе a morе сomplех pat low-rесomЬination AT-ril rесomЬinаtion) rеgions (I tium 2001).

Еvolutionary Faсtorl and Organization

FAстoRs тнAт A IN A GENoМЕ

Among гelatеd spесiеs,u lifе (parasitism or intraс quirеd for survival and rl baсtеriа that nrakе thеir nrurсhsmallеr gеnе numl ехtrеmе rеduсtion lras smallеr thаn еithеr Ьaсtе

Еt,сllution of thе Geпome hwа1.mаygаiп а nеW aЬility to асt on tе a nеW prсlduсt. Sorrrеgеnеs еnсodе rnd inaсtivatingnrutations that affeсt of Ьoth dupliсаtеs,еасlr lvith just tlnе эrv 200З; Lуnсh 2007). This inсгеasеs gеnomе.F.arniliеsof gеnеs that havе nponеntsof Pеnomеs,and solnеtimеs of funсtions,suсh as nrammаls' odorrlant disеasеtrеsistanсе gеnеs (Bauml forrn Ьy fusion of parts of two gеnеs :nе is transсriЬеdЬaсk into DNA and or adjaсеnt to anothеr gеnе (Long ransрositionir-rtothе gеnomе саn аlso )Llt introns (proсеssеtl pseиdogепеs)

REGloNAL DIFFЕRЕNсЕs е pаttеrпs just dеsсriLrеdis vzrriаtiorr (сrossing ovеr) aсross thе gеrrome. in hеtеroсhromatin.RесomЬinаtiсln nаtin. RесorrrЬinatiсlnis frеquеlrtiy .hе сеntromеriс hеtеroсhromarin Ьut lf thе сhromosomе (B. Сharlеsworth Drosсlphilааnd manv plаnts, rесomсilromos
Although it is rrot knowlr how rесomЬinаtion-ratе diffеrеnсеs arе сontrollеd' sеvеralgеnomе fеаturеshavе Ьееn found to сorrеlatе with thе rесomЬination ratе. onе suсh assoсiation is Ьasе сompositiсln (ехprеssеdin tеrms of thе frеquеnсy of GС vеrsus AT Ьirsеpаirs, mеntionеd еаrliеr). In thе human gеnomе tlrе mеan GС сontеrrtis aЬout 41"Ь,Ьut thе сontеnt variеs rеgionally from about ЗО"Ь to 657" (IntеrnationаlHumаn Gеnomе Sеquеnсing Сonsoгtium 200l). Thе GС сontеnts of gеnеs and intеrgеniс sеquеnсеsvаry сonсordantly Ьеtwееn rеgions. Altlrough nonсoding DNA tеrrdsto Ье nrцсh morе AT riсh than сoding sеquеnсеs'thе GC сontеnt of third сoding positiоns (whеrе most mutations do not affесt protеin sеquеnсе)usually сorгеlatеsto somе ехtеnt with that of adjасеnt nonсoding sеquеnсеs.Nonfunсtional sеquеnсеs'suсh as psеudogеnеsand dеfесtivеtransposaЬlееlеmеnts,arе partiсularly intеrеstingЬесаusеthеy rеvеal thе GС сontеnt that will ехist purеly Ьесausеоf thе ir-rputof mutations (without rraturalsеlесtion),аnd thеy rеtlесt thе faсt that thеrе is oftеn a mutation prеssurе toward AT and away from GС (Lynсh 2007)' Iп thе human, С. еlеgапs, and Drosopbilа genomеs, GC сontent is highеst for suсh sitеs in сhromosomе rеgions whеrе сrossovеrratеs aге high (IntеrnationalHuman Gеnonrе Sеquеnсing Сonsortium 2001; Marais and Piganеau 2002). Anothеr сorrеlatе of rесomЬirrarior-ris irrtron lеrrgrh;this tеnds to Ье lowег in high-rесomЬinationrеgions (Сomеron ar-rdKrеitmаn 2000; Intеrnаtionаl Human Gеnomе SеquеnсingСonsortium 2001). In addition, in humans and А. tbаliаtzа (lntеrnational Нuman Gеnomе Sеquеnсing Сonsoгtium 2001; !Иriglit еt al. 2003) gеnе dеnsitiеs arе highеst in thеsе rеgions, Ьut tn С. еlеgаns tЬe oppositе is found (С. еlеgапs Gеnomе Sеquеnсing Projесt 1999). TransposaЬlе.еlеmеntdеnsitiеs also varу rеgionally within gеnomеs. In Drosophilа low_rесomЬinationrеgions hаvе muсh highеr numЬеrs of TЕ in. sеrtions than high-rесomЬination геgions (Kaminkеr et aL.2О02|. Humans havе a morе сomplех pattегn: LINЕ еlеmеnts (TaЬlе 2) arе assoсiatеdwith iow-rесomЬinationAТ.riсh rеgions, аnd SINЕ еlеmеntswith GС-riсh (highrесomЬination)rеgions (IntеrnаtionalНuman Gеnomе Sеquеnсing Сonsort i u m2 0 0 1 ) .

Еvolutionary Faсtors that Contrоl Gеnomе Sizе and Organization FAстoRs тHAт AFFЕст тнE NUMвER oF GЕNЕs lN A GЕNoМЕ Among rеlatеd spесiеs'unusually small gеnomеsarе assoсiatеdwith ways of lifе (parasitism or intrасеllular symЬiosis) whеrе most of thе геsourсеs rе. quirеd for survivаl arrd rеproduсtion аrе providеd Ьy thе host. Foг ехamplе, Ьaсtеria that nrаkе their living as intraсеllular symЬionts or parasitеs havе muсh smallеr 8еnе numЬеrs than frее-living rеlаtivеs (Мoran 2003). Morе ехtrеmе rеduсtion hаs oссurrеd in organеllе gеnorrrеs, whiсh arе muсh smаllеrthan еithеr Ьaсtеrialor nuсlеar gеnomеs;thеy сarry only gеnеsnееdеd

16з

164

Еuolution rэfthе Gепomе for thеir own геpliсation and prtltеin synthеsisand fсlr a fеw spесializеdorganеllar funсtions. Мany gеnеs еssеntial for organеllе fr-rnсtiсlns havе Ьееn trаnsfеrrеd to thе nuсlеus (Gray 1999). ongoing gеnе trаnsfеr hаs Ьееn dеtесtеd frorn plant organеllеgеnomеs,аs wеll as transfеrsthi1tсrеatеnonfunсtional psеudogеnеsof orgаnеllеgеnеsin thе nuсlеar gеnomеsof many spесiеs ( G r a y 1 9 9 9 ;B е n s a s s o nе t a l ' 2 0 0 1 ) . Gеnome-sizе еvolution involvеs sеvеrаl prеssurеs.Thеrе may Ье advantagеs сlf smallеr gеnomе sizе, Ьесausеir rеduсеd gеnomе саn rеpliсatе fastеr, allowing fastеr сеll division; this сarr oссLlr through dеlеtions of gеnеs that arе no longеr nееdеd, or of intеrgеniс and introniс sеquеnсеs.Thе finding that сompaсt gеnomеs oftеn havе ovеrlapping gеnеs, in whiсh thе samе strеtсh of DNA is transсriЬеd in two diffеrеnt rеading frаmеs (Douglas еt al. 2001; l,еwin 2008), suggеststhat sеlесtion fаvorеd sizе rеduсtiorr in thеsе сasеs.But loss of somе sеquеnсеsmay Ье sеlесtivеlynеutral, so that dеlеtions сan Ье fixеd Ьy gеnеtiс drift, as outlinеd еarliеr for rеdundant gеnе dupliсatеs. In nonrеpеtitivе sеquеnсеsthat arе unсonstrainеd Ьy sеlесtion, thе amount of DNA tеnds to dесrеasе ovеr timе Ьесausе rеpliсation rnistakеs sееm to сausе small dеlеtions rnorе oftеn thаn insеrtions of Ьases (Grеgory 2004; Lynсh 2007).If sеlесtivесonstraints on gеnеs эrе rеmovеd, thеy v'.ill thеn gradually dесlinе in sizе ovеr timе аs morе dеlеtionsthan insеrtions Ьесomе fiхеd Ьy gеnеtiс drift. PrtlЬaЬly Ьoth sеlесtivе and nonsеlесtivе prос е s s е sh а v е Ь е е no p е r a t i n g . MUтAт|oN RAтES AND тHЕ NUMBЕRS oF GЕNЕs Мost mutations with еffесts on an organism's funсtions rеduсе survival or fеrtility (fitnеss,for short). Unlеss sеlесtiсlnis vеry wеak, thеrе will Ье a Ьalanсе Ьеtwееnthе mutational input of nеw dеlеtеriousvariants into a populаtion and thеir еliminatiсln Ьy sеlесtion. Thе prеsеnсе of thеsе mutаtions rеduсеs avеragеfitnеss,ссlmparеdwith a mutation-frееpopulatiоn; this mutаtioпаl loаd depeпdson thе totаl numЬеr сlf nеw dеlеtеriousmutations that arisе pеr lndividual еaсh gеnеration,suсh that thе nе!]ativеof thе natural logаrithm of thе mеan fitnеssof a poprrlatiсlnis еqual to thе lоad (Сrow 199з|. For a givеn mutation ratе pеr gеnе, thеrе will thus Ье a grеatеr load if thе numЬеr of gеnеs in a gеnomе is largег. RNA gеnomеs laсk еrror-сorrесting meсhаnisms and havе ехtrеmеly high mutatiсlnrаtеs pеr gеnomе pеr rеpliсation, dеspitе thеir small gеnomе sizе: around 1 nеw mutation pеr rеpliсatiсln сyсlе for thе influеnza virus (Drakе еt al. 1998). Suсh gеnomеsсannot' thеrе. forе, havе largе numЬеrs of gеnеs, Ьесausеthеir {itnеsswoLrld Ьесtlmе vеry low. DNA-Ьasеd gеnomеs havе еrror-сorrесtingmесhanisms that givе thеm muсh lowеr, Ьut not zеro' mutаtion ratеs; theЕ. сoli !]еnomеis еstimаtеdto havе a mutation ratе of around 10_r0pеr nuсlеotidеpеr rеpliсation and a mutation rаtе pеr gеnomе of only 0.0025 (Drakе еt al. 1998). Мultiсеllular сlrganismshavе largе gеnе numЬеrs аnd many сеll divisions еaсh gеnеration.Bесausееrrоr сOrrесtionсlrn nеvеr Ьe pеrfесt,and thе mutation ratе pеr nuсlеotidе pеr сеll division is quitе similar to that in Ьaсtеria,

thе mutation ratе pеr nuсl Ьaсtеria. For ехamplе, in } drashov 2003). Givеn thе n man gеnomе, this translatе protеin sеquеnсеof aЬout tion, and around 80% of tl

nеt mutation ratе to dеlеtе largеr numЬеr of dеlеtеrro thе nonсoding portions of 1 thе еstimatе of thе human H i g h d е l е t е r i o u sm u t а t i (Crow 199З) maу limit p. Thеorеtiсal modеls of thе с сatе that mutatiоnal load 2 0 0 0 ) . H o w е v е r , t h е r еi s l mесhanisms, whiсh slow sourсеs. Thе oссurrеnсеo ratеs to zеro, Ьut in sеxua Ьеtwееn gеnеs' allеlеsthat atеd with favoraЬlе mцtat l i t t l е а d v a n t a g е .М u t а t i o r arе thus likеly to rеflесt tl rеduсing thе mutation rat load (Sniеgowski еt al. 20t I n с o n t r a s t ,i n о r g а n i s m еffесtivе gеnеtiс rесomЬ s P е с i е s .а n a l l е l еt h а t i n с г soсiatеd with any favoraЬ qЦеnсy as thе mutation s1 m u г а t i o n г a t е st h a n i n s е } iпg aпd is obsеrvеd in Ьal sеlесtion prеssurеs(Sniеg

GЕNoMЕ s|zЕ |N oF NoNсoD|NG t

Gеnomе-sizе diffеrеnсеs v o l v е l a r g е d i f f е r е n с е si r DNA, with only minor Lynсh 2007). In somе сa in lifе history and есolo havе morе satеllitе and ot onеs' suggеstingthat thе nеutral with rеspесtto sе

forсеs (likе thе balanсе liеr) providеs a plausiblе

Еuolиtioп of thе Gеnomе ynthеsisand for a fеw spесializеd orial for organеllеfunсtions havе Ьееn ). ongoing gеnе trаrlsfеr has Ьееn dе. ; rvеllirstransfеrstlrаt сгеatе nonfunс_ l thе nLrсlеarЕ]еnolllеs of mаny spесiеs еral prеssurеs.Thеrе may Ье aс.lvanr rеdrr.^еd 8еnomе сan rеpliсаtе tаstеr, lссur through dеlеtiсlnsof gеrrеsthat and intror-riсsеquеnсеs.Thе tinding еrlapping gеnеs, in whiсh thе samе iffеrеntrеadingfranrеs(Douglas еt al. сtiorr fаvorеd sizе rеduсtion irr thеsе lе sеlесtivеlyoeutfell,so that dеlеtions r е d е a r l i е rf o r r е d u n d a n tg е n е d u p l i arе unсonstrainеdЬy sеlесtitln, thе 'еr tinlе bесausеrеpliсation пristakеs геn thаn insеrtionsоf Ьаsеs (Grеgory llnts on gеnеsаrе rеmovеd' thеy vyill as morе dеlеtionsthan insеrtions ЬеЬotlr sеlесtivе:ttlс{ntlnsеlесtir,еpro-

UMBЕRs oF GЕNЕs ganisш'sfunсtions rеduсе survivаl or tion is vеry wеak, thеrе will Ье a Ьаlеw dеlеtеriousvariаl-ltsinto a ptlpr'lla. n . Т h е p r е s е n с еt l f t h е s е m u t i l t i o n s а п1l-ltation-frее population this mu. Ьеr of nеw dеlеtеriсlusmutations that :h thаt thе rrеgativеof thе naturаl logi o n i s е q u a lt o t h е l o а d ( С r o w 1 9 9 З \ ' еrе ш'ill thus Ье а grеatеr loасl if гhе . R N А g е n o m е sl a . . k е r r o r - с o r r с с t i n g lutаtion ratеspеr gеnomе pеr rеpliсa.ound 1 nеW mutаtior-r pеr rеpliсаtion t. 1998).Suсh gеrromеsсannot, thеrеausе thеir fitnеsswould bесoпrе vеry orrесtingmесhanismsthat givе thеm еs;thе Е. сoli gеn()пlеis еstimatеd to r nr.rс[еotidе pеr rеpliсаtion :rnс{а muDrakееt al. 1998). еnе numbеrs and nrany сеll divisions )n сan nеvеrЬе pеrfесt,аnd thе mlltаn is quitе similаr to thаt irr Ьirсtеria,

thе mutation rаtе pеr nuсlеotidе sitе pеr gеnеration is muсh highеr than in baсtеria.For ехamplе, in humans it is еstimatеd to Ьe aЬout 2x10 8 (Kondraslrov2003)' Givеn thе numЬеr of sitеsthat сodе for amino aсids in thе human gеnomе, this translarеsirrto a mutation гatе pег 8еnomе foг сhаngеs in protеin sеquеnсеof aЬout 0.82 nеw пltltаtions pеr individual еасh gеnеra. tion, and around 80"Ь of thеsе arе likеly to Ье slightly dеlеtеrious,yiеlding a nеt mutation ratе to dеlеtеriоusamino aсid mutations of aЬout 0.66. An еvеn largеrnumЬеr of dеlеtеriousmutаtions is likеly to Ье сilusеd by mutаtions in thе nonсoding portions of tlrе human gеnomе (Asthаna et aI.2О07),Ьringing thе еstimatеof thе human dеlеtеriousmutation ratе to wеll aЬovе 1. Нigh dеlеtегiousmutation гatеs and thе rеsulting low population fitnеssеs (Сrow 1993) may limit possiЬlе gеnomе sizеs for multiсеllular oгganisms. Thеorеtiсаlmodеls of thе еvolution of gеrrеsthat сorrtrol mutatiol-lratеs indiсatе that mutational load favors a rеduсеd mutation ratе (Sniеgowski еt al. 2 0 0 0 ) .H o w е v е r . t h е г еi s a n o p p o s i n g p r е s s u r е :t h е с o s t s o f е r r o г - с o r r е с t i n g mесhanisms,whiсh slow down DNA rеpliсation and сonsumе сеllular rеsollrсеs.Thе oссurгеnсе of irdvantagеousmutations аlso disfаv
165

l66

Еuсllutiсlttof thе Сепotпе

proсеssеstlrаt invo|vе еrr()rsin DNA rеpliсаtion irrrdrtnеqual сrossin!]ovеr саn amplitr, аrril\rsbу multiplеs сlf rvhсllеrеpеаtеd units, sо thеrе аrе forсеs thаt inсrеasе сopy numЬеr' somеtimеs adding DNA to thе gеnonrеof an individrrаl;gеnеtiсdrift сan tlrеn сausе it to sprеad to fixation (B. Сhaгlеswсlrth еt аl. ] 994;' LуncЬ 2007). Sеlесtiсln against high сopy nuпrЬеr will oftеn opposе this proсеss' Ьut suсh sеlесtion is lеast еffссtivе in spесiеswith а small еffесtivеpopulаtiсln sizе (Kimr.rrа198з). This suggеststhаt thеrе should Ье а rеlаtion Ьеtwееnthе еffесtivеsizе оf a spесiеs (whiсlr сan Ье еstimatесlfroпl its lеr.еl of DNA sеqllеnсе с.livегsity;11,nсЬ2007) and thе сontгiЬutirln oi rеpеtitivс sеquеnсеsttl its gеnomе sizе. Broаd сomparisons aсross diffегеnt taхa suPport this prеdiсtion (l-ynсh 2007). Hor'vеvеr,spесiеssuсh as D' uirilis and D. mеlапсlgаstеr diifer сonsidеrably in thеir аmount of rеpеtitivе DNA Ьuг sееm to havе similar еffесtivе рopulation sizеs (Drrlsophilа 72 Gеnomеs Сonstlrtium 20О7I. Тhis suggеsts thаt othеr faсtors must plav a гсllе. A likеli" disadvantagеof a largе anlount of sаtеllitеDNA is a slolvеr dеvеlopnlеllt timе, sinсе сеll с]ir,isionswill Ье slow lf it takеs longеr to геpliсatе gеn()mеswith largе DNA аnlсtunts(Cavaliеr-Smith1985). \Whеnrapid dеvеlopmеnt is important, thе Ьalanсе is tippеd towаrd lowеr сopy numЬеr, but i{ slow dеvеlopmеnt is not disfavorеd Ьy sеlесtion' sеlесtion against thе aссumulаtiоn of rеpеtitivеDNA ц,ill Ье wеakеr, аnd sr.rсlr sеquеnсеsсan aссLlmLll а t е ( F i g t r r е4 ) . T h u s l a r g е D N A с o n t е n t d < l е sn o t n е с е s s a r i l yi m p h , t l r а r sеlесtiotlhаs favorеd nroгеDNA (Pagеland Jсllrnsttrnе1992'B. Сhirrlеsworth еt al. 1994). Of сoursе, it might somеtilnеs Ье advantagеotlsto havе morе nonсoding DNA. For instanсе' morе DNA pеr nuсlеus might еnaЬlе organisms with largе сеlls to movе RNA morе rapidly into thе сvtoplasm (Саvaliег-Snrith 1985). Нсlш. сan onе distingtrislrЬеtwееn thеsе possiЬilitiеs? Ехpеritrrеnts thаг altеr thе i.rпrountof hеtеroсhrolnatin in D' пrclапogLlstеrhardly rrffесt viaЬilitr, сlr dеvеlopmеnt tilr-rе'suggеstingtlrat largе сhangеs in сopy numЬ е r s ( m i I l i o n s o f Ь a s е s )h а r ' е a t m o s t v е r y s l i g Ь t a d v a n t a g е so r d i s а d v a n tagеs (John and Miklos 1988). Vеry slight fitnеss diffеrеnсеsсan, howеvеr, Ье importаnt in еvсllution, so this is not сonсlusivе' In сomparativе tеsts thаt еxаnrinе dеvеlopmеnt tiпlеs and gеnomе sizеs irсross diffеrеnt spесiеs, thе bаlаnсе rrrodеlprеdiсts thilt а rеlationship will Ье fсlund еvеn аftеr st..t-..---> insеrtion5, inс|uding rереatаdditions 5ma|| sаtе|litе

insеrtiопs, |аrge iпс|uding ТЕs

small genome <<-

prеssurе undеrmUtаtiOn dеlеtions

fаvorеd sе|есtivеIy deletiоns <--UПPЧU3| сrossing ovеrwithgenetiс drifl

lаrge genome highсostsof rеplасing DNA slowgrowtfl

Figurе 4. Oppсlsing forсеs aсtir.rgOn gеnomе.sizе сvrlIution.

tistiсal сorrесtions for diff. this is not ехpесtеd if thеr. from salamarrdеrs and nе Johnstonе 1992). Сan wе sее thе footprir . sizеs, as assumеd еаrliеr? сonсеntration in rеgions o w е с a n . T h е а r g u m е n ti l r \ ' ray undеrgoеs unеqual сro pliсations). Unequal ехсhz сopiеs in thе array. Ьut it i

Ьеr is nеithеr advantagеous spесiеs to Ьесomе fixеd for rеquirеs multiplе сopiеs, a r aftеr rеmain singlе сopy (t сopiеs сan Ье lost again Ьy that affесt array sizеs, thе с a tandеm arrаy thus produ ity ovеr timе that thе pop

сially if unеqual еxсhang individuals with high аrra rеsulrs. Largе агrays aris (B. Chaгlеsworth еt a|. \99, low-rесomЬination gеnomi forсе that pushеs rеpеat n forсе that aсts in thе оppos No funсtional advanta DNA sеquеnсеs is tlrus nt thеir distributiоn within gс latеd spесiеs oftеn diffеr quеnсеs' whiсh also strong ]v{iklos 1988; Drosophilа doеs not mеan that satеlli Drosopbilа, portions of t} mosomal Ьеhаvior at lnеlo volvеd in сеntromеrе [un probaЬly did not сausе t} morе likеly, thеsе arrays v liеr and wеrе latеr сo-optе тRANsPosAвLЕ

Е

Мost typеs of transposa t h е m s е l v е si n t o n е w p o s i t nal сopy. Thеsе transpos m е n t n u m Ь е r so v е r t i m е u For ехampl e, tn D. mеIап

Еuolиtioп of the Geпomе эliсationand unеqual сrosslng ovеf з rеpеаtеdunits, so thеrе arе forсеs tding DNA to thе gеnomе of an insprеасlto fiхаtion (B. Сhаrlеswoгth lst high сopу numЬеr wil| oftеn op'ast еffесtivеin spесiеswitlr а small This suggеststhаt thеrе should Ье а lесiеs(rvhiсhсаn Ье estimatеd fгom nсh 2007) and thе сontriЬution of Broаd сompагisons ilсross diffегеnt 7).Нowеvеr, spесiеssuсlr as D. uirгaЬly iп thеiг amount of rеpеtitivе з population sizеs (l)rosг-lphilа 12 .еsts that otlrеr faсtors must plaУ t of sаtеllitеDNA is a slowеr dеvеlsiow if it t:rkеslongеr rсl repliсatе i е r - S m i t h1 9 t l 5 ) W . hеn rаpid dеvеll towirгd lou,еr сopy nun-rЬеr,lrut if эlесtion,sеlесtionagainst thе aссuэr, and suсlrsеquеnсеsсаI1aссulnult doеs not nесеssarily imply that rdJсlhrrstonе1992:B. Сhагlеswoгth ltltаgеousto hаl,е nrorе nonсoding :lеusrnight еnaЬlе organisms with n t o t Ь е с y t o p l a s m( С a v а l i е r - S m i t h ln thеsе possiЬilitiеs? Ехpеriments n in D. mеlапсlgаstarhаrdly affесt g thаt largе сhangеs in сopy num' r y s l i g h t a d v a n t а g е so r disadvаnlt fitnеssdiffеrеnсеsсan, howеvеr, t с o n с l u s i v е .l n с o l n p а r а t i v е t с s t s t o m е s i z е sа с r o s sd i f f е r е l r rs p е с i е s , nship will Ье found еvеn аftеr stadditions--------->

+ -

lаrge genome highсosts ofrеplасing DNA slowgrоwth

-sizе еvolutiоn.

tistiсalсorrесtions for diffеrеnсеs in nuсlеar volumе and сеll sizе, whеrеаs this is not expесtеd if thеrе is an advаntagе of more DNA. Сorrесtеd data from salarnandеrs and nеWts still show a signifiсant rеlation (Pagеl and Johnstonе 1992). Сan wе sее thе footprint сlf a mutational prеssurе that inсrеasеs аrray sizеs,as assumеd еarliег? Thе distriЬution of sаtеllitе DNA, with a strong сonсеntration in rеgions of infrеquеnt gеnеtiс rесomЬination, suggеsts that wе сan. Thе аrgumеnt involvеs a simplе modеl in whiсh a tandеm rеPеat array undеrg
167

168

Еurllиtiсlnof thе Gепomе nеw TЕ is addеd to a haploid еuсhromatiс gеnomе еvеry 10 gеnеrationsin laЬoratory сonditions whеrе sеlесtionis rеlaxеd (Мasidе еt al. 2000). Thеrе arе aЬout 1,000 fairly сomplеtе TЕs in thе gеnomе (Kaminkеr еt al. 2002), so thе mеan transpositiсlnrаtе pеr pсltеnгiallyaсtivе еlеmеnt is aЬout 10 a pеr gеnеration. \й/hatrеgulatеsthе aЬundanсе of TЕs in thе gеnomе? Thеrе arе two сontrasting viеws (B. Сharlеsworth еt al. 1994). First, TЕs сould Ье maintainеd Ьесausе thеy arе advantagесlusfoг thеir host organisms; for instanсе' thеy might oссasionally induсе favorаЬlе mutations Ьy insеrting into gеnеsor rеgulatory sеquеnсеs.A proЬlеm with this idеа is that insеrtions mostly сausе harmful, not advantagеous' еffесts, disrupting сoding or rеgulatory sеquеnсеs. Many known spontanеous dеlеtеrious mutations' inсluding somе human disеasе mutations' аrе duе tо insеrtions into сoding sеquеnсеs(os. tеrtag and Kazazian 2001). Suсh strongly dеlеtеriousmutations are usuallv rapidly еliminatеd from populations, and аs mеntionеd еarliеr, it is indееd oЬsеrvеd that in thе gеnomе sеquеnсеsof highеr organisms TЕs arе largеly absеnt from ссlding sеquеnсеs'indiсating that insеrtions thеrе arе harmful (Intеrnational Human Gеnomе SеquеnсirrgСonsortium 200l ; Kaminkеr еt a|.20О2; \Х/rightеt al. 2003). F.urthеrеvidеnсеthat TЕ movеmеnt is disadvantagеous to thе host is that marry spесiеs,suсh as yеast' thе mold Neиrosporсt, maizе, and Drosophilа' Ьaуe mесhаnisms that rеstriсt thе ratе of movеmеnt of TЕs (Sеlkеr2002; Aгavin et aI.2ОО7).Мorеovеr, thе viеw that TЕ insеrtions arе advаntagеousfor thеir hosts' futurе еvolution rеsts on thе idеa that thе long.tеrm survival of a spесiеsis еnhanсеd Ьy thе pгеsеnсеof TЕs, and it doеs not ехplain how TЕs Ьесomе еstaЬlishеdin thе first plaсе. Sесond, TЕs сould Ье maintainеd Ьy thеir aЬility to sprеad by sеlf-rеpliсation within thе gеnomе, сouplеd with transmissiсln of nеw ссrpiеsto thе offspring during sехual rеprоduсtion, еvеn if thеy usually havе hаrmful еffесtson thеir hosts (thе selfish DNА hypothеsis).on this viеw TЕ aЬundanсе will dеpеnd on thе Ьalanсе Ьеtwееntransposition that сausеsinсrеasеdсopy numЬеr vеrsus sеlесtion against individuals with largе сopy numbеrs (B. Сharlеsworth et a|. 7994; Lynсh 2007). This Ьalanсе impliеs thаt thе rеduсtion in fitnеss сausеd Ьy аn еlеmеnt insеrtion musr on avеragееqual thе сhanсе that an еlе. mеnt transposеs. Еstimatеs of this ratе arе around 10_apеr gеnеrаtion in Drosophilа, showing that this sеlесtionprеssurеmust Ье wеak. This hаs Ьееn tеstеd furthеr in D. mеlапogаsterЬy dеtеrminingеlеmеntpositions on thе giant сhromosomеs of larval salivary glands. Thе frеquеnсiеsof TЕ insеrtions in thе population arе nеarly always vеry low at a givеn plaсе on thе сhromosomе, again implying that insеrtionsarе disadvantagеous.Thе strеngthсlf sеlесtion сan Ье infеrrеd from thе frеquеnсiеs,аnd it agrееswith thе еstimatеd transposition ratе (B. Сharlеsworth еt аl. 1994|. \Х/hat is thе naturе of this sеlесtion? \iИеhavе alrеady disсussеd sеlесtion against largе gеnomе sizе, and harmful еffесts of transpositions on thе host. Anothеr disаdvantagе сomеs from сr:ossingovеr Ьеtwееn еlеmеnts in diffеrеnt gеnomiс loсations (ecto|liс ехсhапge), This сausеs сhromosomе invеrsions, transloсations,dеlеtions,and dupliсations(B. Сharlеsworthеt al. 1994). Somе

rеarrаngеmеnts havе fеw bесausе of gеnеtiс drift, l mosomе struсturе. BLlt n highly dеlеtеrious:many J aгrаngеmеnrs (gспсlmiс 2003). If this is an impo prеdiсts that TЕs should сomЬination ratеs,sinсе mеnts and will thеrеforе есtopiс еxсhangеs. As mе proportion сlf thе Y сhrс quеnсеs (B. Сharlеswortl planations for this pаttеr of thе gеnomе with rеdu Т Е s m а y s o m е t i m е 5i n mеnts' and sеlесtionwill TЕ-dеrivеd sеquеnсеsap or сonfеr сlthеr Ьеnеf]ts satеllitе sеquеnсеs,hоwс tion pгomotеd thе initia tory or еvеn сoding funс w е r е i n s е r t е di n t t l t h е i г1

МAsslvЕ тE Aсс sIzЕ DIFFЕRЕNс

A | t h o u g h t h е r a t е о | :i г D. mеlапсlgasler sееms l roughly еvеry 10 gеnеra tionary timеsсаlеsif no с tгansposition еstimatеd D r o sop b ilа gеnеratiOns danсes among rеlatеd s еarliеr, arе thus rеadily somеtimеs rеlaхеd. Anо whiсh аn autosomе Ьес yеаrs ago; this has sinс this gеnomе rеgion to st сur in Droso1lhilа ma|e sity of TЕ insеrtions intс somе spесiеs (е.g.,hurna (TaЬlе 2), and at many q u е n с i е s( o r е v е n i n a l l j

r n g ,w i t h t h е | o w i n s е r t i .Why arе thеrе suсh l lаrgеr amounts of intе

Еtlolutioп of thе Gепomе ltlс gеnomееvеry 10 gеr-rеrations in rеlaхеd(Мasidе еt al. 2000). Тhеге е gеnomе(Karninkеrеt al. 2002), so Llly асtivе еlеmеnt is aЬсlut 10_apеr in thе gеnomе? Thеrе i1геtwo сon. 94). First, TЕs сould Ье maintainеd . host orgarrisпrs; for instаrrсе. thеy rtiorrsЬy insеrtinginto gеnеsOr rеgidеa is tЬat insеrtions f]lostly сatlsе srllрting сoding or геgulatoгУ sе_ еtеriousmutations' inсluding somе sеrtionsinto сoding sеquеnсеs (os|y dеlеtегioLrs mutаtions аrе usuall1, d as mеntionеdеarliеr, it is indeеd эf highеr organisms TЕs arе largеly g tЬаt irrsеrtionstherе аrе harmful сing Сonsortium 2001; Kamirrkеr :vidеnсеthat TЕ movеmеnt is disadlсiеs, suсh as уеаst' rhе nrold Nсzllесhanisms th:lt rеstriсt гhе ratе of r aL.2007). Мorеovеr, tЬе viеw tЬat hosts' futr:rееl.o]utionгеsts on thе сiеs is еnhanсеdЬy thе prеsеnсе of :omе еstaЬlishedin thе Iirst plaсе. ir aЬilit1'to sprеerd Ьy sеlf-rеpliсation ssion of nеw сopiеs to thе offspring rsuallyhavе harmful еffс:сtson thеir h i s v i е r д , , T aЕ Ь u n d a n с еw i l l d е p е n d t сattsеsinсrеasеdсopy rrumЬеrvеrgе сopy numЬеrs (B. Сlrarlеsworth mpliеs that thе rеduсtion in fitnеss vеrаgееqual tl-rесhanсе thаt an еlеа r е a r o u n d l 0 - a p е r g е n е r a t i o ni n :еssurеmust Ье wеak. Thls has Ьеегr :miningеlеmеntpositions on thе gi. ls. Thе frеquеnсiеsof TЕ insеrtions oW at a givеn plaсе olr tЬе сhrt>molisadvantagеoшs. Thе strеngthof sе'еs,and it agrееswith thе еstimatеd 19941. Vе lrаvе alrеady disсussеd sеlесtion [fесtsof transpositions on thе host. g ovеr bеtwееnеlеmеnts irr diffеrent h i s с а u s е sс h r < l m о s o n tiеn v е r s i o l r s , (B. Сharlеsworthеt al. 1994). Somе

rеarrangеmеnts havе fеw or no harmful еffесts and саn sprеad in populations in сlrrobесausеof gеnеtiс drifl, thеrеЬy сorrrriЬuting to еvolutionary сh:rr-rgе mosomеstruсturе. But many rеarrangеmеnts disrupt gеnе funсtions аnd аrе highlydеlеtеrious:nrany humаn gеnеtiсdisеаsеsаrе сausеdЬy сhromosomе rеаrrangеmеnts(gепсlmiс disеclsеs),inсluding mаny саnсегs (Dеiningеr еt аl. 2003).If this is аn importalrt disаdvurntаgе tо having high TЕ aЬundanсе, it prеdiсtsthаt TЕs sЬould aссltmulatе mainly in gеntrmiс геgions rvith low гесomЬinаrtionrаtеs' sinсе tlrеy arе tlrеп lеss likеly tсl саusе harnrful rеarrangеmеntsаnd will thеrеforе not Ье rеmovеd Ьy sеlесtion against thе produсts o{ есtopiсеxсhangеs'As mеntiсltlеdеarliег, this is oftеn truе' For ехanrplе, a largе pгоportion of tlrе Y сhromсlsоmеs of many spесiеs сonsists of ТЕ-dеrivеd sе_ quеnсеs(B. Сharlеsworth еt a|. |994|. Howеvеr, thеrе arе othеr possiЬlе еxplanatiоnsfor this pattеrn' srrсhas thе геduсеd еffiсiеnсy of sеlесtiоrrin rеgitlns of thе gеrromеwitlr rеduсеd rесoпrЬinаtion(sееlаtеr disсr"rssiorr). TЕs miry somеtimеsinduсе favoraЬlеmutations or сhromosomе rеarrangеmеnts'and sеlесtionwill thеrl sprеad thеm throughout thе pсlpulation.Son-rе ТЕ-dеrivedsеquеnсеsаppе21rto rеgulаtеgеnе асtivity (Dеiningегеt аl. 200З) or сonfеr othеr Ьеnеfitson thеir hosts (Brookfiеld 2003). As wе arguеd for satеllitеsеquеnсеs'howеvеr, a prеsеnt-dayЬеnеfitdoеs not impl,v that sеlесtion prсlmotеdtlrе initial sprеаd of tlrеsеsеqtlеnсеs.lr is possiЬlе thаt rеgulа_ tory or еr,еnсodin8 funсtions havе Ьееn aсquiгеd by suсh TЕs long aftеr tlrеy wеrеinsеrtеdinto thеir Prеsеnt loсations and fiхеd in thе population. MAssIVЕ тЕ AссUМULAт|oN AND PoPULAт|oN sIzЕ DIFFЕRЕNсЕs Although thе ratе of inсrеаsе of TЕs Ьy trаnsposition in spесiеs suсh as D. melаnogаsle/sееmslow (onе nеw еlеmеnt in thе haploid gеnomе еlеmеnt гoughlvеvеry 10 gеnегations)'сopl,numbеr lvill inсгеasеrapidl,vovеr еvolutionarytimеsсalеsif no oppсlsingfoгсе opеrаtеs:for еxаlmplе,with thе ratе of transpositiсlnеstimatеd еarliеr, a tеnfold inсrеasе woLlld takе only 2з,000 Drosopbilа gеnеrirtiotls,lеss tlran 2,000 yеars. Lаrgе diffеrеnсеsin TЕ аЬLrrrdanсеsamong rеlаtеd spесiеs,аs in thе maizе and riсе ехamplеs dеsсriЬеd еarliеr,aге thus rеadily ехpliсaЬlе if sеlесtion prеssuгеs against thеm аrе sоmеtimesrеlaхеd. Arrothеr ехamplе is proviсlеd Ьу Drosсlphilа mirаndа, itl whiсh art autos()nlеЬесаmе attaсhеd to thе Y сhromosomе аЬout 1 million yrars ago; this hаs sinсе Ьееn transmittеd only from fаthеr to son, сausing this gеnomе геgion to stop rесomЬining ЬесаusеrессrmЬirrаtiondoеs not oссur in Drr,,sophilа ma|еs.Тhе rеgion has sinсе thеn aссumulatеd a high dеnsityof TЕ insеrtionsinto nonсoding sеquеnсеs(Baсhtrog 2003)' Gеnomеs of somеspесiеs(е.g.,lrumаns arrd mаizе) lrаvеa vеry higЬ ovеrаIlTЕ aЬundarrсе (Тablе2), and at many сhromosomal sitеs, TЕs may bе prеsеllt at high fгеquеnсiеs(or еvеn in all individuals) (Ostеrtag and Kazazian 2001)' сontrasting lvirh thе low insегtiсlnfrеquеnсiеsin Drosсsphilа. \fhy arе thеrе suсh largе diffеrеnсеsЬеtwееn spесiеs?Pеrhaps thе пruсh largеr аnrounts of intеrgеniс DNA and largеr introns in humans than in

1,6L)

1 7 0 Еuolutioп of tbе Geпomе Drosophilа п1еаnthat insеrtions hаvе lеss risk of сausing harmful mutations (although this would not Ье tгuе if intеrgеniсrеgions' sеquеnсеsoftеn сontrol genе aсtivity). A morе intеrеstingpossiЬility dеpеnds on thе wеaknеss of sеlесtion against еaсh nеW TЕ insеrtion. If TЕs rarеly ехсisе from a sitе, gеnеtiс drift сan somеtimеs lеad tо a sitе Ьесoming iгrеvеrsiЬlyfiхеd for an еlеmеnt. In spесiеs with low population sizеs, suсh as humans, sеlесtion against еlеmеnts is lеss еffесtivеin opposing gеnеtiс drift' and this possiЬly allows thе prеssrrrеfor еlеmеnt Ьuildup to prеdominatе (Lynсh 2007I. Nеw insеrtions into аlгеady_оссupiеdsitеs woшld flot Ье prеvеntеdЬy sеlесtion(thеrеwould Ьe no direсt hаrmful еftесts,just a slightly grеatеr risk of есtopiс еxсhangе), and so еlеmеnts сould snowЬall ovеr timе. This may aссount for thе fixеd еlеmеnts in mаnrmalian gеnomеs' Ьut rrot for thе vеry high TЕ aЬundanсе in maize, a spесiеswhosе high DNA sеquеnсеvaгlaЬility indiсatеs a largе population sizе (Tenaillon еt al. 2002I. RесomЬination in maizе may Ье largеly сonfinеd to gеnеs' so that TЕs in intегgеniс sеquеnсеs сould not Ье rеmovеd Ьy есtopiс ехсhangе. Thus еlеmеnts would Ьuild up Ьеtwееn gеnеs' as oЬ. sеrvеd (SanМiguеl еt a|. 1.996)'Нowеvеr, thе сausаtion сould Ье thе othеr way round: TЕs may simply rесomЬiпе lеss than l.lostsеquеnсеs. тHЕ ЕVoLUтIoNARY сoNsЕoUЕNсЕs oF GЕNЕтIс RЕсoMвINAт|oN AND PoPULAтloN s|zE SеlесtionagainstTЕs is only onе Way in whiсh small population sizе and laсk of rесomЬination сan Ье importаnt for gеnomе еvolution. RесomЬination rаtеs play important гolеs in numегous еvoluгionаryproсеssеs'еspесiallythе еvolutionary advantagеs and disadvantagеsof sехual rеproduсtion. Sеvеral diffеrеnсеs among gеnomе rеgions аrе сonnесtеd with rесomЬination ratе diffеrеnсеs' аnd thе еffесts of low rесonrЬination rаtеs arе similar to thosе of small еffесtivеpopulаtion sizе (Gоrdo arrd Chaгlеsworth 2001). Sеx and rесombinаtiorr аllow sеlесtion to aсt indеpеndеntly on diffеrеnt sitеs within thе gеnomе. This inсrеasеsthе еffiсiеnсy of sеlесtion.For ехample,if favorаblе mutaсions arisе indеpеndеntly, but vеry rаrеly' at two sitеs, thе populаtion will rarеly сtrntainany individualsthat сarry douЬlе mutants'еvеn if this is thе fittеst сomЬination (unlеssthе populаtion sizе is so hugе that thе sесond mutation еvеnt happеns Ьеforе sеlесtion fiхеs the first favoraЬlе mutation). Gеnеtiс rесombination allows thе douЬlе-mutant сomЬination to Ьe formеd. Whеn thеге is littlе or no eеnеtiс rесomЬination' or whеn rеproduсtion is asеxual, sеlесtioп on onе gеnе thus impеdеs sеlесtion aсting on othеr gеnеs' making fаvoraЬlе mutations lеss likеly to sprеad and dеlеtеrious mutаtions (suсh as amino aсid сhаngеs in prоtеins) moге likеly to Ье fiхеd Ьy gеnеtiс drift, paгtiсularly whеn population sizеs arе low (Gordo and Сharlеsworth 2001). This Proсеss proЬaЬly сontriЬutеs to gеnon-lеrеduсtion in symЬiotiс Ьaсtеria that livе within inseсt сеlls (rесomЬination bеtwеen Ьасtеria of thеsе spесiеs is prеvеntеd by isolаtion);thеsеrеduсеdgеnomеsalso havе fastеramino асid sеquеnсе еvolution' as prеdiсtеd givеrrthе lowеrеd aЬility of sеlесtionto еliminatе mutations with wеakly disаdv:rntagеous еffесts(Мoran 2003).

Gеnеs irr gеnonrеr.еgion similar еvolutionаry proсеs еls of adaptation. Тhis ma сomЬirring сhrotnosomal rt (pегh:rpsаlso in pаIt саLls strikingly illustrаrе thе ( D . С h а r l е s w o r t hе t a i . 2 0 С s o m е g е n е s ' Ь е t г а r ' i n gr h е paiг, Ьut tlrе Y laсks n)()st(

thе gеnеtiс informаtion onс nonrес()mЬiningсhromoso p е d е t h е i r а Ь i l i t yr o m a i n г fastеr than tЬеir Х-linkеd d i s а d v e n г а g е o u sr . e r i e r l t si gеnеs thаn likе normal gеn s е s o f s е х . l i n k е dg е n с si n ( F г i d o l i s s o nа n d Ё l l с g г е n. gеnеs addеd to thе Y сhro сonfirm гhetthis is duе tll i mutations (Bartolсlrnёand Similar Ьut mildеrеffесt gions with diffегеntrесoml сodons that еnd irr G or С сontеnt of third сoding pos oг thе аdjaсеnt r-ronсtrdi gапs, and А' thаlitlпа, tЬerс геflесts thе aсtion of sеlес fastеr аrrd/or morе aссurаt tеin sеquеirсе(AkasЬi еt al is' horvеvеr, vеr1' small сo protеin sеquеnсеs.so that prеfегrеd ovеr AТ. In an o сomPonеnt of tlrе gеllomr whеrе rесomЬination is in1 mal сodon usagе шight Ье would Ье lеss Ьiаsсdthаn o f t h е o Ь s е r r ' е r ]r е l l t i o n s сontеnt of сoding sеquеn and for thе wеakеning of tесtеd for thе gеnеs addеd and Сharlеswсlrth 2006). Horvеvеr, thе GС с()ntе С. еlеgапs also с
Еuolutklп rlf the (}uюtпе l risk of сausingharmful mutations niс rеgions'sеquеnсеsoftеn сontrol ity dеpеndson thе wеaknеss of sе.Еs raгеly еxсisе from a site, gеnеtiс rg irrеvеrsibly fiхеd for an еlеmеnt. э as humans' sеlесtion against еlе: drift, and this possiЬly allows thе laге (Lynсh 2007). Nеw insеrrions lrеvеntеdby sеlесtion (thеrе would r grеatеrrisk of есtopiс ехсhangе), . Тhis may aссOunt for thе fixеd еl[or thе vеry high TЕ aЬundanсе in эе vaгiaЬilityindiсatеsa largе popтbination ir-rrnаizе may Ье largеly iс sеquеnсеsсould not Ье rеmovеd ld Ьuild up Ьеtwееn gеnеs' as oЬ' thе сausationсould Ье thе othеr ;s thurnhost sеquеnсеs. :NсЕs oF GЕNЕт|с

.IoN sIzЕ

lriсh smali population sizе and laсk ]еnomе еvolution. RесomЬination olutionaryproсеsses,еspесially thе еs of sеxuаl rеproduсtion. Sеvеral эnnесtеd with rесomЬination rate ination ratеs arе similar to thosе of l Сhirrlеsworгlr2001 ). )aсt indеpеndеntlyon diffеrеnt sitеs :nсy of sеlесtion.For еxamplе, if favеry rагеly, at rwo sitеs, thе рopuat сarrУdouЬlе mutants' еvеn if this rtion sizе is so hugе that thе sесond es thе first favюrаЬlеmutation). Gе.utant сomЬination to Ье formеd. Ltion,or whеn геproduсtion is asехсtion асting on othеr gеnеs,making rnd dеlеtеriousmutations (suсh аs , to Ье fiхеd Ьy gеnеtiс drift, partiсгdo and Сharlеsrvorth 2001). This :duсtion in symЬiotiс Ьaсtеria that 'ееnЬасtеriаof thеsеspeсiеsis pгеalsohavеfastегаmino асid sеquеnсе l i l i t yo f s е l е с t i o n г o е l i m i n a t еm u t а Мoran 2003)'

Gеnеsin gеnomе rеЕ]ionstlrat lасk gеnеtiс rессlmЬinatiсlnshould r.rndеrgo similarеvolutionirrvproсеssеsthar iпrpеdеsеlессionаrrсllеаd tсl rеduсеd lеvеls of аdaptation.This may also сontгiЬutс to thе Ьuildup of TЕs in nonrесomЬiningсhromosomal rеgions and to thеsе rеgions' inсrеasеd intron sizеs (pеrhapsаlso irr p2rrtсausеd Ьy ТЕ-dеrivеd matсrial). Y sех сlrгomos
171

172

Еuolutiсlпrlf thе Gепome ratеs. сеrtainly, not all mutаtions oссLlr еqually frеquеntlv' As аlrеady mеntionеd, thе rеlativеly high AТ сontеnt of nonсoding DNA is сausеd by mutational biаs toward AT. A proсеss that may opposе this is biаsеd geпе сonuеrsion; Ьесausе of thе molесular mесhаnism of gеnеtiс rесomЬination' whеn onе gеnomе has GС at a sitе and thе samе sitе in thе othег has AT, rе. сomЬination сan pгoduсе a vеry slight ехсеssof GС in thе daughtеr gеnomе (Мarais 2003). This will inсгеasеGС сontеnt in Ьoth сoding and nonсoding sеquеnсеs' сausing GСs to Ье fiхеd moге frеquеntly than ATs' just as though GСs wеrе favorеd by sеlесtion.Bесausе it is paгt of thе rесomЬination proсеss, Ьiаsеd gеnе сonvеrsion is еxpесtеd to aсt mainly in rеgions with high ratеs of rесomЬination, lеading to a highеr GС frеquеnсy in suсh rеgions. Thiгd positions of сodons will havе an аdditionаl еnhanсеmеntof GС from thе еffесtsof sеlесtion for сodorr Ьias' Statistiсalanalysеsof thе GС сontеnt of thе gеnomе of D' mеlаnogаstel"supPort this hypothеsis, as do data from thе highlу rесomЬining parts of sеx сhromosomеs of nrammаls (Мarais

2 0 0 )З.

Соnсlusions Gеnomе еvolution, likе othеr еvolutionаry сhangеs, is opportunistiс. Сhangеs in gеnomе fеaturеs hzrvесonsеquеnсеsof two kinds. First, сhangе may lеad to fuгthеr сhangеs. For instanсе, сhr{rmosomеrеaгrangеmеntsaffесt rесomЬination. A gеnе сan movе into a rеgion of lowеr or highеr rесomЬination, affесt. ing thе Ьаlаnсе Ьеtwееn Ьiasеd gеnе сonvеrsion that pushеs GС сontеnt up vегsus mutation Prеssurе in thе othеr dirесtion, So that GC сontеrrt will start сhanging. If a rеarrаngеmеntrеduсеs rесomЬinаtion, as happеns whеn a сhromosomе arпr is joinсd to a Y сhromosomе, thе dесrеasеdaЬility of natrrrаl sеlесtion to еliminatе wеaklу disadvаntagеousсhangеs may ultinratеlylеad to thе loss of funсtionality' or еvеn thе physiсal prеsеnсе'of gеnеs from this сhromosomе' as indееd has hаppеnеd in D. пtirапdа (D. Сharlеsworth еt al. 2005). Sесond, еvеn whеn a gеnonlе fеaturе еr,olvеswitlrout Ьеing favorеd Ьy individual sеlесtion,thеге сan oссasionаlly Ье pоtеntially advantagеouseffесts for organismal funсtions. For ехamplе, TЕs that сontain sеquеnсеsthat сontrol thе ехprеssion of thеir own gеnеs саn аlso аffесt thе aсtivity of gеnеs сlosе to thеir insеrtion sitеs.Initially parasitiс sеlfishDNA (sprеadingpurеly as a сonsеquеnсеof sеlесtion for thе sеquеnсеs'own aЬility tо rеpliсatе)сan ..domеstiсatеd'' bесomе as a part of thе gеnomе of a spесiеs,prеsеntin all individuals аnd funсtioning in its host, rathеr likе thе organеllеs'whiсh wеrе onсе indеpеndеntorganisms (Broоkfiеld 2003). This possiЬility is often ovеrlookеd, Ьut it is important to avoid thе naivе attitudе that prеsеnt.davЬеnе. fits сan ехplain thе origin of irll gеnomе fеatuгеs. Genomе еvоlution is far morе сomplех than straightforward adaptivе еvolution Ьy natural sеlесtion,and many fеaturеsmay havе hаd a long history in gеnomеs Ьеforе аny Ьеnеfiгs t
latiol.lsizеs dесrеаsеdas п trons еxp()sеs gеnеs t() с] сhangе thе prсltеin irnd spliсir-rgmust Ье сOnsегvе Ь y s е l е с t i o nt l n l y i n s р с с i prеssurе inсrеаsеs intron pгokllry
ous tеsts of hypothеsеsthl BIвLIoGRAPнY

A k а s h i 'H . , R . l \ { .K l i m а n ,a

s е | е с t i с l r rl r n d т h е е r ' t > | t

49-60. Thе ArаЬidopsis Cеnсlmе In flсllvеring plмtt Аrаbidl, Arаvin, A. A.' G. J. Hanпtln рrovidеs an aсlirрtivеdе Asthаl-rа,S., \и. s. NoЬlе, G. St:rnll-ttovаnnсlgl
Еuolutioп сlf thе cепolпе еquаllyfrеquеntly.As alrеаdy mеnnonсodingDNA is саusеd Ьy mutа: mаy opposе this is biаsеd gепe :сhanismof gеnеtiс rесomЬination, 1е samе sitе in thе othеr has AT, rе:сеssof GС in thе daughtеr gеnomе ltеnt in Ьoth соding and nonсoding tiеquеntly than AЪ, just аs though it is part оf thе rесomЬination proto aсt mainly ir-rrеgions with high hеr GС frequеnсy in suсh rеgions. dditionalеnhanсеmеntof GС 1rom .ltistiсаlanalysеsof thе GС сontеnt 'rt this hypothеsis,as do data from lromosomеs of mammals (Мarais

, сhаngеs'is opportunistiс. Сhangеs wo kinds. First, сlrangе may lеad tо lе rеaгrangеmеntsaffесt rесomЬinavеr or highеr rесomЬination, affесtvеrsion thаt pushеs GC сontеnt up сtion' so that GС сontеnt will start lЬination, as happеnswhеn a сhгol, thе dесrеasеdability of naсural sе)us сhangеs may ultimatеly lеad tо al prеsеnсе,of gеnеsfrom this сhro,апdа(D, Сharlеsworth еt аl. 2005). ,.olvеswithout Ьеing firvorеd Ьy inЬе potеntially advantаgеous еffесts Еs that сontain sеquеnсestЬаt сontn аlso affесt thе aсtivity of gеnеs sitiс sеlfishDNA (sprеadingpurеly еnсеs'own aЬility to rеpliсatе) сan nomе of a spесiеs'prеsеnt in all inrеr likе thе оrganеllеs, whiсh wеrе 003).This possiЬility is oftеn ovеr'ivе аttitudеthat prеsеnt-dayЬеnеaturеs. гhanstгaightforwаrd adaptivе еvolrеsmay havе had a long history in аnism еvolvеd. Iг hаs еvеn Ьееn эrеadwithin gеnomеswhеn popu.

lаtionsizеsdесгеаsеdаs rrruIriсеllrrlаг orgаnisпrsеvolvеd.Thе prеsеlrсеof introns ехposеs gеnеs to ехtrа hаrmful mutations in addition to thosе that сhangеthе pгotеir-rand ссlrrtгollirrgsеquеnсеs (Ьgсдu5gsiгеs rеquirеd for spliсingmust Ье сonsеrvеd).It is ptlssiЬlеthаt thеir prеsеnсесan Ье rеsistеd Ь,vsеlесtiononly irr spесiеsrvith vеry l:rrgеpсlpulations.IГ somе rlrutational prеssurеinсrеirsеsintron nunlbеrs. this соuld aссOllnt for introns' rarity in рrokaryotеsand prеsеrrсеin multiсеlltrlar еuk:rryotеs(Lynсh and Сonеry 2003;Lynсh 2007). SеIесtionmау аlstl firvoг small рrokarvotе gеllomе slzе for othеrrеasons' llut in prinсiplе all rrpposingforсеs must Play somе rolе. Again, horvеvеr,it sеепrs unlikеly tlrаt n.rutirtiсlпаl prеssllrе ехplains thе prеsеnсеof аll intгons in gеnеs of living multiсеllular еukaryсltеs,еspесially Ьесausеintron sizе and nunlЬеrs сan dесrеаsе,аs wеll as itrсrеasе(this has happеnеd.frrr instаnсе,in thе smаll gеnomе of thе plant А. tbаliапа;.Wright еtal.2002). \й/hаtеvеrthе сausеsof thеir initial origins, introns havе еvolvеd to Ьессlt-l-tе dоrnеstiсаtеdаnd l-rаvеасqrrirеd сеllulаr funсtiсrns' as wе lrevе suggеstеd for othеr gеn()mеfеaturеs,and thеrе is inсrеasing еvidеnсе for sеlесtivесonstrail-tгs tltr intгtln аrrd lr in Drosоphila.cепеtiса1'О2.. 49-60. ThеAгаЬidopsis GеnоmеInitiativе. 200.l. Аnаlysisof thе gеnomеsеqr.rеnсе of thе florvеringplantArаbidсlpsisthсtli.lпа.Nаturе 40B:796_8l.5. Aгavirr, A. A.' G..J.Fiаnnoп,аnd'|.Brеr-rnесkе. 2007.Тhе Piwi-piRNA раthwav providеs an adaptivес1еfеnsс it.rthе trаrlspоsоll ]rп1sraсе.SсicttсеЗ18 76|-764, , . S u n v a е ra, ,n d . l .A ' A s t h a n аS.. , . WS' . N о Ь l е ,G . K r у . L r k oСv ., Е . ( ] r а n t S Stamato1'аnnoроulos. 2007. WidеlydistriЬutеd nоrtсodirrg puгifvingsеlесti
17.1

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20ЗЗ-2044.

Baumgartеn,A., S. Сannon, R. Spаnglеr' and G. Мay. 2003. Gеnоmе-lеvеl еvolution of rеsistanсе gеnеs in Arаbidopsis thаliапа. Geпеtics 165 ЗО9_319. Bеnsasson,D., D. х. ZЬang, D. L. Hartl, ar-rdG. М. Неwitt. 2001. Мitoсhondrial psеudogеnеs:Еvolution's misplaсеd witnеssеs. Trепds iп Ессllogу апd Еuoluthn 16:314-321. Brookfiеld, J. F. Y. 2003. МoЬilе DNAs: Thе poaсhеr turnеd gаmеk eеpеr.Сurrепt Biologу 13: R846-R847. Bruggmann' R., A. K. Bharti, H. Gundlaсh, J. S. Lаi, S. Young, A. С. Роntaroli, F..S. \Wеi,G. НaЬеrеr, G. Fuks, С. G. Du, С. Rаymond, М. С. Еstеp, R. Y. Liu,.|' L. Bеnnеtzеn'A. P. Сhan' P. D. Rabinowiсz, J. QuaсkеnЬush, W. B. BаrЬazuk, R. A. Wing' B. Biггеn' С. NusЬaum' S. Rounslеy, K. F' Х. Мayеr' and J. Меssing. 2006. Unеvеn сhromosomе сontraсtion and ехpаnsion ir"rthе mаizе gеnomе. Gепome Resеаrсh 16: 124,|_1251. Burt, A., and R. L. Trivеrs. 2ОО6. Geпеs iп Сoпfliсt: Thе Biolсlgу of Sеlfisb Gепеtiс Еlеmепts. СamЬridgе, МA: Harvard Univеrsity Prеss. Сavaliеr.Smith, Т. 1985. Тhе Еuolutioп of Gеnсlme Slzс. Сhiсhеstеr,U.K.:.|ohn !(iilеy. С. еlеgапs Gеnomе Sеquеnсing Prсljесt. 1999. How thе woгtт was Won. Trепds iп Gепetiсs 15: 51-58. Сharlеsworth' B., P. Sniеgowski,and W. Stеphan. 1994.The еvolutiоnary dynamiсs of rеpеtitivеDNA in еukaryotеs.Nаturе З71:215-220. Сharlеsworth, D., B. Сharlеsworth, and G. Мarais. 2005. Stеps in thе еvolution of hеtеromorphiс sех сhromosomes. Неrеditу 95| 118*128. Сomеron' J. M.' and M. Krеitman. 2000. Thе сorrеlation Ьеtwееnintron lеngth аnd rесombinаtion in Drosophilа: ЕquiliЬrium Ьеtwееnmutational and sеlесtivе forсеs. c eпеtiсs 1 5 6: 1 77 5-|190. Сrow, J. F. |993. Mutation, mеan fitnеss, and gеnеtiс load. Охford Suruеуs of Еurllutioпаrу Biologу 9 : 3-42. Dеiningеr, P. L.' J. V. Moran, М. A. Batzеr, and Н. H.Kaz'azlan.2003. Mоbilе еlеmеnts and mammalian gеnomе еvolution. Сurrепt Оpiпioп iп Gепеtiсs апd D euelсlpmепt13: 65 1_658. Douglas, S., S. Zаunеr, М. Fraunholz, М. Bеaton, S. Pеnny, Х. N. \йИu,М. Rеith' T. Сavаliеr-Smith' аnd U. G. Maiеr. 200l . Тhе Ьighly rеduсеd gеnomе of an еnslavеdaigal nuсlеus.Nаturе 4I0: 1О91-J'096. D r a k e , J . W . ' B . С h a r l е s w o r t h ,D . С h a r l е s w o r t h 'а n d J . F . С r o w . l 9 9 8 . R а t е s o f spontanеousmutation. Gепеtiсs 148l.1667-1686. Drosсlphilа 12 Gеnomеs Сonsortium. 2007. Еvolution of gеnеs and gеnсlmеsоn thе Drosophila phylogеny' Nаturе 4.50:203_21 8. Еiсhlеr, Е. Е., and D. Sankoff. 2003. Struсtural dynаrniсsof еukaryotiс сhromosomе еvolution. Sсiспсе 3О|: a93_797. Еlgin' S. С. R., and S. I. S. Grеwal. 200З. Hеtеroсhromatin:Silеnсеis gоldеn. Сurreпt Biologу 13: R895_R898. Fridolfsson, A., and H. Еllеgrеrr.2000. Мolесulаr еvolution of thе aviаn СHD l gеnеson the Z and.W sеx сhrоmosomеs. Gепеtiсs 15.5:1903-1912. Gеrrаrd, D. T., and D. A. Filatov. 2005. Positivе irnd nеgativеsеlесtionon mammalian Y сhromosom еs' Мсlleсulаr Biolсlgу апd Еurllutioп 22: 142З-1432, Gordo, I., and B. Charlеsworth.2001. Gеnеtiс linkаsе аnd molесulаr еvolution. Сurreпt Biologу 11: R684_R686.

Gray, М. W. 1999. Еvolutiсlrro апd Dеuеlopmспt 9: 67B_( Grеgсlry, T. R. 2004. lnsеrtton Gепе З24: 1-З4. Halligаn' D. L., and P. D. Kеig D ro sop b ilа gеt.lomеrеvеaI Rеsеаrсh 16: 875_884. Н a r v е v ' P . Н ' , a n d M . P a g с l .1 1 Bioklgу'. oxford: oхford l IntеrnatiсlnаlНuman Gеnomе l analysis of thе human gеnс John, 8., ar.rd(i. L. G. Miklos. Еuolutioп, Lоndon: Allеrr l Joyсе, G. F. 1989. RNA еvоlut Кaminkеr, J. S.' с. М. Bеrgma .!7hееlеr, S. Е. Lеrvis D. A. 2002. Thе tlansposаЬlе еlс gеrronliсs pеrspесtivе. Cсl' K a u p p i , l - . , A . S а j а n t i l a 'а n d A than populatiоrr histсlrydс rеgion. Hиmап Мolесulаr Kimura' М. 1983. Тhе Nеutrtll СаrтЬridgе Univеrsity l)rе Kondrаshov' A. S. 2003. Dirес 20 loсi саusing Мсndеliаn Lеlvin, B. 2008. Gепеs lX.Lol Long, М. 2001 . Еvoiution оf n Dеuelopmепt I1 : 673_68( Lyr-rсh,NI. 2007. Тhс Оrigiпs t Assoсiаtеs. L y n с h ' М . ' . l n с |. | .5 . ( , t l r l е r y 2. ( 1401-1404. Маrais, G. 2003. Biаsеd gеnе с еvolution. Тrепds iп Сепе Mаrais, G., аnd G. l)igаnеаrr d е t е r m i n а n to i v i t г i : t t i о l r Сае пor h аb ditis еlеgаtls gе 1з99-|406. Mirsidе, Х., S. Аssimасoрoulos transposaЬlе еlсmеnts сrn1 Gепеtiсаl Rеsеаrсh 7 5..27 МomЬeеrts, P. 2001. Thс hurт Аttпиаl Rеu psеudсlgеt.tеs. Мrlran, N. A. 2003. Traсing t| symЬionts. Сurrепt Opiпi Мousе Gеnomе SеquеnсingСt anаlysis of thе mсlusс gеn Мyеrs, S., l,. Bottolo, С. Frееп m . r p с l f г е с о m Ь i n l t t i о nг . l t З1О З12-З24. Oсhmurn,H.' J. G. LawrеIrсс,: thе nаturе of Ьirсtегiаlirrn Ostеrtag, Е. M., and H. Н. Ka rеtrotranspos ons. Аll rluttl

Еuolutioп tf thе Gепomе ]ekimi' 199.5.Меiotiс гесombination' l in (,аепorhаbditiselеgапs. Gепеtiсs llution of amino-асid sеquеnсеsand еo-sехсhrсlп-lоsot-t-tеs. Gсиel iсs 17 4: -i.Мay. 200.]' Gеnоmе-lеvеl is thаliаnа, Gепetiсs 165 ЗО9-З]-9. ] . М . Н е w i t t . 2 0 0 1 .М i t o с h o r r d r i а l ;ses.Trепds iп Есtllogу апd Еuolutioп oасhеrturnеd gamеkееpеr.Сurrепt i. Lаi, S. Yоung, A. С. Pontaroli, F. s. rymond, Nl. С. Еstеp, R. Y. Liu, J. L. J. QuасkеnЬush,!и. B. BarЬаzuk, unslеv,K. F. Х. Мayеr, and J. raсtionand ехpansiсlnin thе mаizе 1. nfliсt:Tbе Bioklgl' of Sеlfish Gепetiс сrsity Prеss. юmе Sizе.Сhiсhеstеr,U.K.: John How thе Worm Wаs won, Trеnds iп, an. 1994.Thе еvсllutior-rаry dynamiсs 712215-220. rrais'2005. Stеpsin thе еvolution of y 95:I 18-128. сorrеlationbеtwееnintrоn lеngth аnd bеtwееnmutаtiоnаl аnd sеlесtive gеnеtiс load. oхford Sиrueуs сlf d H. H. Kazazian.2003. MoЬilе n. Сurrепt Opinioп iп Gеnеtiсs апd on, S. Pеnny,Х. N. Wu, М. Rеith, ' Тhе highly rеduсеdgеnomе of an 1096. h, and J' F. Crow. 1998. Rаtеs of 7-1686. ,olutionof gеnеsirnd gеnоmеs on thе :i8. dynаmiсsof еukaryotiссhromosomе гoсhromatin:Silеnсеis goldеn. lar еvolutionof thе аvian СHD 1 Эепetiсs15 5 : 19ОЗ_|9 |2. ,'еand nеgativеsеlесtionon iologl апd Еuolиtioп 22: 1423_|432. linkagеand molесulаr еvolution.

Grаv,М. !и. 1999. Еvolutiorr оf organеllar gеnomеs.Сurraпt Оpiпioп iп Сепеtiсs апd Dеuеkl1lmепt9: 678_687, Grеgоry,T' R' 2004. Ir.rsегtion.с]еlеtitln Ьiasеsаnd thе еvсllutionof gеnоmе sizе. Cutе 32.4:|-31. Hаlligan,D. L., and P. D. Kеightlеу.2006. UЬiquitous sеlссtivесonstraints in thе DrсlsophilаgетromеrеvеаlеdЬy а gеnomе-widеsеquсrrсесompаrison. Сепfgеnе loss in oЬligatе Ьасtеriаl symbionts.СьtrrепtOpiпfutt iп Мiсrobiolсlgy 6: 512_.518. N{ousе(iеrrсlrnеSеquеnсirrgСoпsorrium. 2002. Irritialsес1Llеnсing аnd сonlрarаrivе analysisof thе morrsеgсnomе. Nаtttrе 420 520-562, ,N{vеrs, S., L. BоttсlIo' С. Еrееmагr,(i. MсVеаn, аrrd P. I)сlI-rrrеtty. 200.5. A firrе-sсаlе nrap of lссоmЬinatiоn rаtеs and hotspots асross thе huпlan !]еnomе.Sоепсс Jl0:ЗI2_з21. oсhmаn. H., J' G. Lаwrеnсе' аnd Е. A. Groismlln. 2000. Lаtеrаl gеnе trаnsfеr аlld thе niltrrrесlf Ьtсtеriаl innсlvаtiсln.NLlturе405:299-.]04. ostеrtag,Е' M.' аnd H. H. Kazаzian. 2001. Biology оf mаn.rmаliаnL.l rетrоtfilnsposotls. Аttпuаl Ilеuiеtuof Сепеtiсs.].5:.501_5З8.

17-\

1 7 6 Еuolutiсln of thе Gепome Pagеl, М., and R. A. Jсlhnstonе. 1992.Уariation aсross spесiеs in thе sizе of thе nuсlеar gеnomе suрports thе junk-DNA ехplanation for thе C-valuе paradoх. Proсеediпgsof thе Roуаl Soсiеtу of Londoп, Sеriеs B 249:119-124, Piеgu, B., R. Guyot, N. Piсault, A. Roulin, A. Saniyal, H. Kim, K. Сollura, D. S. Brar, S. Jaсkson, R. A. !Иing, and o. Panaud. 2006. Doubling gеnomе slzе without polyplоidization: Dynamiсs of rеtrotransposition-drivеngеnomiс еxpansions in Оrуzа аиstrаliеnsis, a wild rеlativе of riсе. Geпome Resеаrch 16 1262-\269. Ranson, H.' С. Сlaudianos' F. Ortеlli, С. AЬgrall, J. HеmingwaУ' М. y. Sharakhova, M. F. Ungеr, F. H. Сollins, and R. Fеyеrеisеn. 2002. Еvolution of suреrgеnеfamiliеs assoсiаtеdwith insесtiсidеrеsistanсе.Sсieпсе 298: \79-|81. SanМiguеl' P., A. Tikhonov, N. Jin, N. Мotсhulskaia, А', Zakharov, A. МеlakеЬеrhan, P. S. Springеr' К. J. Еdwards, М. Lее, Z. tvramova, and J. L. Bеnnеtzеn. 1996. Nеstеd rеtrotransposons in thе intеrgеniс rеgions of thе maizе gеnomе. Sсiепсe273: 7 65-7 69. Sеlkеr, Е. U. 2002. Rеpеat.induсеd gеnе silеnсing in fungi. Аduапсеs in Сепetiсs 46: 439450. Sharp, P. М.' Е. Bailеs, R. J. Groсoсk,J. F..Pеdеn, and R. Е. Soсkеtt.2005. Vаriatiоn in thе strеngth of sеlесtеd сodon usagе Ьias among Ьaсtеriа. Nuclеiс А с i d s R е s е а r с hЗ З : 1 | 4 1 _ | | 5 З . Sniеgowski, P. D., P. J. Gеrrish' T. Johnson, and A. Shavеr.2000. Thе еvolutiоn of mutation ratеs:Sеparаtingсаusеsfrom сonsеquеnсеs.Blo-Еssауs22: 1057_\О66. Suilivan' B. A., М. D. Blowеr' and G. H. Karpеn. 2001. Dеtеrmining сеntromеrе idеntity: Сyсliсal storiеs аnd forking patЬs' Nаturе Rеuiеt'usGепеtiсs 2: 584-596. Теnaillon, М. I., M. С. Sawkins, L. K. Andеrson' S. M. Staсk, J. F. DoеЬlеy, and B. S. Gaut. 2002. Pаttеrnsof divеrsity and rесomЬinatiоn along сhrоmosomе 1 of maizе (Zеа mауs ssp.m[lуs L.|. Gепеtiсs 1'62:1401_1'41З. Viеira, С., С. Nardоn, С. Arpin, D. Lеpеtit' and С. Bi6mont.20О2. Еvolution of gеnomе sizе in Drosophila: Is thе invadеr's gеnomе Ьеing invadеd Ьy transposaЬlе еlеmеnts? Мo Ieсu lаr B i o l ogу аn d Еu o lиt klп 1'9: 1 1'5 4_1'1'6I. 'Wаlsh' B. 1995. Нow oftеn do dupliсatеd gеnеs еvolvе nеw funсtions? Geпеtics J. 1.39:421.-428. .Wong, S., G. Butlеr, and K. H. !Иolfе. 2002. Gеnе ordеr еvolution and palеopolyploidy in hеmiasсomyсеtе уeasts. Proсееdings of thе Nаtioпаl Аcаdеmу сlf Sсiеnces USA 99 9272_9277. .lfright, S. I., N. Agrawal, and T. Е. Burеau.2003. Еffесts of rесomЬination ratе аnd gеnе dеnsity on transposaЬlе еlеmеnt distriЬutions in Аrаbidopsis thоliапа. Geпomе Resеаrсh 13: 1897-1903. .!7right, S. I., B. Lauga, and D. Сharlеsworth. 2002. Ratеs and pattеrns of molесular еvoiution in inbrеd and outЬrеd AraЬidopsis. Мoleculаr Biologу аnd Еuolиtioп 1'9:'1'4О7-1'42О. ZЬang, x. H.-F., and L. A. Сhasin 2006. Сomparison of multiplе vеrtеЬratе gеnomеs rеvеals thе Ьirth and еvolution of humаn ехons. Proceеdiпgs of the NаtioпаI Асаdemу of Sсieпсes USА 103: 13427-|з4з2.

Thе Pattе of Spесia

IvLаrgаrеtB. 1

Thе еssсntial Ьit сlf сvo gin trnd n:lturе of speсl

Spесiation' thе еvolr-rtion and maintаin thеir indеpе non еvеr sinсе Darwin (1

divеrsifiеd from sharеd an ing how spесiation oссurs О с с u r r е di n г h е p e s t ' l е з v i thеir оссurrеnсе. Spесiеs,l tiсs assoсiatеd with thеir rion, thеy аlso сarrу uni oссurrеd sinсе spесiation thе spесiation proсеss fro paгtiсularly diffiсult. Sесtlnd, nеW spесiеs ar ( е . g . , n a t u r a t s е l е с t i o n ,s t thеrеforе, finding a unifyir an impossiЬlе сhallеngе.T spесiеs сharасtеristiсs anr nomiс, systеmatiс' and сo F i n a l l y .s p е с i e t i o ni 5 а .

divеrgеnсе, a middlе stag Ьy various forсеs of еvolu сomеs a сomplеtеly sеpa еvolutionary сhangе witlr tion into nеw linеagеs(FiE сontinuum tlf spесietion tionаry Ьiologists whо w this hurdlе, tЬе study сlf l

ing arеas of еvolution:rry

esin the size of the : the C-valueparadox. 19 119-124. m, K. Collura, D. S. ,ublinggenome size rn-driven genomic ;. GentnneResearch\6: 4way.M. V. sen.2002. Evolution of :. Science298 179-1'81'. rkharov,A. 1.Avramova,and J. L. ;enicregionsof the maize Adtancesin Genetics 46: ,. Sockett.2005. .mongbacteria.Nwcleic 2000.The evolution of BioEssays22: 'terminingcentfomere uiewsGenetics2: ck, J. F. Doebley,and ion alongchromosome 1 - 14 1 3 . rt. 2002. Evolution of ing invaded by ion 19: 1154-1161. ew fnnctions? Genetics ,olution and 4sof tbe National rateand of recombination Arabidopsisthaliana. a n d p a t t e r n so f m o l e c u l a r lar Biologyand Euolution nultiple vertebrate tns. Proceedingsof the )L.

The Patternand Process of Speciation Margaret B. Ptacek-dnd ShalaJ. Hank"ison Tl-reessentialbit of evolutionary theor\.which is concernedrvjth the origin and nirture of spet:iesremainsr.rtterlyrnyster',.rut. *. Batcso. (192r)

Speciation,the evolutionary processby which new and distinct lineagesarise and mirintain their independenttraiectories,has been a perplexingphenomenon ever since Dirrwin (18-59)first proposed that all living organisms have frorn sharedancestors.There are severalreasonswhy unclerstanddiver:sified i n g h o w s p e c i a t i o no c e u r si s c h e l l c n g i n g .F i r s t . m o s t s p e c i r r i o nt v c n t s h r v c occurredin the past, leaving only the end products, species,:rs a signattrreof exrant and extinct tornts, [re,rrthe cher,rctcristheir occurrence.Species,l.r
178

The Раttеrп апd Proсеss of Spесiаtioп

Speсies

Speсies

sеlесrion.gеnеtiс drrft. a gеnotypiс diffеrеnсеsbеtш how аnd why nеw spесiе in whiсh nеw spесiеs аrе primary mеans Ьy whiсh n dеnt еvoIr-rtionarypathwa hаvе Ьеgul.rto rеsсllvе thе

Еxтlшстloш

Thе Naturе of Spесi

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Common Anсestor Figurе 1. Thе proсеssof speсiationis a соntinuum.InitiaIdivеrgеnсеЬеtwееn populatiоnsis followеd Ьy а pеriod of anаgеniссhangеwithin еaсh nеw linеagе whеrеin spесiеs.spесifiссharасtеristiсsarе rеfinеd Ьy various forсеs of еvolution. In somе spесiеslong pеriоdswith littlе еvolutionaryсhangе(stasis)may ()ссur. onсe formеd,spесiеsmay furtherdivеrsifyinto nеw linеagеs(сladogеnеsis) or may Ьесomе ехtinсt. Thе сhallеngеin thе study of spесiation is unсovеring whеre along this сontinuuma spесiеsaсtuallyеxists.

еvolutionary Ьiologists ovеr thе past 15 yеars has lеd to mаny ехсiting advanсеs. Thеsе inсludе thе disсovеry of sеvеral spесiаtioп gепеs that сonfеr rеproduсtivе isolation, a Ьеttеr undеrstandingof thе importanсе of sympatriс spесiation (spесiationwithоut gеographiсisolation);and a геsurrесtionof intеrеstin how natural sеlесtionсan lеad to thе formatiсlnof nеw speсiеsas Ьyproduсts of adaptivе diffеrеntiation. In this еssaywе outlinе somе of thе major сhallеngеsin undеrstandingspе. сiation and showсasееxamplеs that illustratеthе major advanсеsin thе study of thе origin and divеrsifiсation of spесiеs. wе start with thе proЬlеm of dеfining spесiеs, and how an undеrstanding of thе undеrlying meсhanisms that lеad to thе formation of nеw spесiеs may Ье the Ьеst approaсh in attеmpting to dеfinе what a spесiеsrеally is. Nехt, wе outlinе thе various rypеs o f i s o I a t i n gЬ а r r i е г st h a n с а n i n i t i а t е 'p r o m o t е .a n d с o m p l е t еt h е s p е с i a г i o n proсеss.Finally' wе disсussthе еvolutionary mесhanismsthаt drivе thе spесiation proсеss. Outlining thе rеlativе rolеs thаt natural sеlесtion, sеxual

Spесiеs сonсеpts, :r sеt ot a Ь o u n d i n t h е l i t е r a t u r е( } lсlng-standingdеЬatе enro lеm is сеntеrеd arсlund ir pаttеrn-oriеntеd
Whаt do wе do with all dеfinе spесiеs irnywаy? T

Тhc Pаttеrп апd Prсlсеssof Spесiаtiсlп 1 7 9

Speсies D

peсIes с

Ct-дooсвшвsls

sеlесtion,gеnеtiс сlrift, and mutаtion plаv in prom()titlg phеnotypiс and gеnot1,piс diffеrсnсеsЬеtwесn populations is сritiсal to our undеrstanding of how ar-rdwhy nеw spесiеsarisе. Our gсlal is not t() сovеr еvеry potеntial way in whiсIrlrеw spесiеs аrе formес.lЬшt rathеr tсl illustratе with ехаmplеs thе primarymеans Ьy whiсh nеw s1-lесiеs arе f
Thе Naturе of Spесiеs }Sтдsls

Aшдсrшвsts

)mmon nсestor гinuum.InitialdivеrgеnсеЬеtwееn ;еniссhirngеwithin eaсh nеw linеаgе 'еfinеdby variousfoгсеsof еvolr.rtion. utionaryсhangе(stasis)may oссuг. into nеw linеagеs(сladogеnеsis) сlr , u d yo f s p е с i а t i o ins u n с o v е r i n g lly еxists.

yеars lras lеd to m:rny еxсiting ad.era|spесiсttio|1 gеnrs that сonfer rеing of thе importanсе of sympatriс : isоlation);and a rеsurrесtionof inthе formation of nеw spесiеsаs Ьyjor сhаllеngеsin undегstandingspегatеthе major advirnсеsin thе study :iеs.\7е start with thе proЬlеm of ling of thе undеrlying mесhanisms ]s may Ье thе Ьеst approaсh in at. N е ч г ,W еo u t l i n еt h е v а г i o u s t y p е s )motе' and сomplеtе thе spесiation try mесhanismsthat drivе thе spесillеs thаt гtаtural sеlесtion. sеxual

SpесiеsсOnсеpts'a sеt of rulеs tlr сharасtегistiсsusеd to dеfinе a sPе1'igs' abotrndin thе litеratuге(N[ir,vdеn|997;ТaLl|e l)аnd hilr,еЬееn a srrЬjесtof long.stаndingdеЬаtеamong еvсllr"rtionary Ьiсllogists.Tlrе naturе of rhis proЬlеm is сеntеrеdarоund a disagrееnrеntЬеtwееn еv
1 8 0 Тhе Pаtterп аnd Procеss of Spесiаtiсlп Tablе 1. Spесiеsсonсеpts'thеir dеfinitions'and rеfеrеnсеs Spесiеs сonсеpt Patternoriеntеd Biologiсal

Dеfinition

D o Ь z h a n s k y1 9 3 7 ; Groups сlf intеrЬrееding natural populationsthаt Мaуr 1942,196З аrе геproduсtivеlyisolatеd from othеr suсh groups.

Сohеsion',

Thе most inсlusivеgroup of organismshаvingthе potеntialfor gеnеtiс and/ordеmogrаphiс еxсhangеаЬility. Phеnеtiс A sеt of organismsthаt look similar to еасh othеr and arе distinсtfтom othеr suсh sеts. Rесognition A sеt оf populationsthat shаrеa сOmmon fеrtilization systеm (spесifiс mJtе-rесOgn itit-ln systеm). Proсеssoгiеntеd Сohеsion'.

Rеfеrеnсеs

Thе most inсlusivе group of organisms having thе potеntial for gеnеtiс and/or dеmographiс ехсhangеaЬility.

T е m p l е t o n1 9 8 9

Sokal and Сrovеllo 1970

P a t е r s o n1 9 8 5

Tеmplеton 1989

Есologiсаl

A sеt сlf organismsаdаptеd уanУa|en 1'976 to a singlеесologiсаlniсhе, еvolving sеparatеlyfrom linеаgеsoutsidеits rаngе. Еvolutionary A singlеlrnеagе S i m p s o n1 9 61 ; (an anсеstral-dеsсеndant W i l е y - l 9 7 8 sеquеnсеof pоpulations) еvolvingsеparatеlyfrom othеrsand with uniquе еvolutionarytеndеnсiеs and its own historiсalfatе. P h y l o g е n е t i сT h е s m a l l е s t d i a g n о s a Ь l е С r a с r a f t1 9 8 3 , сlustеrof individual t989 organismswithin whiсh thегеis а parеntаlpаttеrn оf anсеstryаnd dеsсеnt. ".Pаrts оf dеfinition сonsidеr Ьoth pаttеrn and prоссss сlf spесiation.

Figurе 2. An illustrаtionof } d i f f е г е n tp o i n t s i n t h е s p е с i .Whеn divеrgеntlir into two. SpесiеsСonсеpt (ЕсSС) will rеprоduсtivеisolation (ISM1 sеparatеspесiеsundеr thе B rеPrеsеntmonоphylеtiссlad сommon anсеstor)ЬеforеЬс SpесiеsСonсеpt (PSС).

sсiеntists сall spесiеs sееm сannot sееm to agrее.Thе having somе form of dеfiт еvеn if diffеrеnt spесiеs rt ariеs. First? dеfining Ьiolog nеr in whiсh to сlassify.

Sесond, dеfining diagnosa еntitiеs that еxist in naturс spесiеs aгisе without havir plaсе. Fourth, spесiеs,as thе еvolutionary history O surеd Ьy thе numЬеr and usuallymadе at thе spес сatеgorizing and сonsеrvl

T'he Pаttcпt аrld Proсеss of SDесiаtion and rеfеrеnсеs Rеfеrеnсеs intеrbrеесling D o Ь z h a n s k y1 9 3 7 ; lulationsthat Мaуr 1942,1963 lсtivеl1, isolatеd srrсhgroups. -rсIusivе group T е m p l е t o n1 9 8 9 ls havingthе lr gеnеtiс rоgrаphiс rility.

Lr'

BSс

Sokal and Сrovеllo ;anismsthаt r to еасhothег 1970 tinсt fтom othег pulаtiоnsrhat Patеrson-l985 nmon l systеm rtе-rесogniгion nсlusivеgroup ns havingthе )I gеnеtlс rographiс rility.

Tеmplеton1989

adаptеd van Vаlеn 1976 ;arrisms есologiсаlniсhе, paratеlyfrom tsidеits rangе. Simpsоn 196 1; аl-сlеsсеndа nt Wilеy 197tl f populations) paratеlyfrom with r"rniqr-rе .y tеndеnсiеs r lristoriсalfatе. sr diаgr.rosaЬiе С г a с r а f t1 9 8 З , rdividual 1989 withinwhiсh arеntalPattеrn and dеsсеnt.

tеagе

l р r о с е ь sо f s р е с i l l т i о n

Figurе2. An illustr:rtionof lrorv diffеr:еntspесiеsсonсеpts dеfi.rеspесiеsat diffеrеntpoints in thе spесiationproсеssaftеr thе splittingof a siфlе linеаgе into two. lfhеrr divеrgеntlinеagеsdispеrsеinto diffеrеntЬaЬitats'ihе ЕсоtЬgiсal SpесiеsСсlnсеpt(ЕсSС) will dеfinе tlrеrnаs sеpаrаtеspесiеs.Thе еvolutiоn of rеproduсtivе isolation(ISM1 or ISM2) Ьеtwееnthе two linеаcеswill сlеfinе sерaratе spесiеsundеr thе BiologiсalSpесiеsСorrсеpt(BSС). iinеagеs must rерrеsеnt monсlphylеtiссiadеs(all p<rpulаtiсlr.rs irгеdt-sсеndе.i frсlm а singlе с o m m o na n с е s t о rl)r е f r l г е Ь е i n gr е с t l g r l i z еаds s p е с i е su n t l е гt h е P h y I o g е n е r i с Sресiеs Сonсеpt (PSС).

sсiеntistsсall spесiеssееm to know thеir own Ьoundariеs' еvеn if biсllоgists саnnotsееm to agrее.Thеrе arе, howеvеr' somе vеry impоrtant геаsons ftrr h a v i n gs o m е f o г m o f d е f i n i t i o nt h a t s с i е n t i s t sс а n u s е г o г е с o g n i z еs p е с i е s , еven if diffЪrеnt speсiеs rеquirе different сritеria for dеfining thеir Ьoundariеs.First, dеfining Ьiologiсal еntitiеs аs spесiеsprovidеs a svstеmatiсmannеr in whiсh to сlаssify divеrsity and is thе Ьаsis of modегn taхonomy. Sесond,dеfining diagnosaЬlе groups as spесiеs соrrеsponds to thе disсrеtе еntitiеsthat ехist in naturе. Third' onе сannot study thе proсеss of how nеw spесiеsarisе without having somе dеfinition сrf what a spесiеs is in thе fiгst plaсе. Forrгth, spесiеs, аs thе lеast inсlusivе саtеgory of сlivеrsity, rеprеsеnt thееvolutionaryhistory of organisnrs'Finаlly, Ьiodivеrsity is gеnеrally mеasurеdЬy thе numЬеr аnd kinds of living organisпrs,and thеsе еstimаtеsarе usuallymadе at thе spесiеs lеvеl. Thus for a variеtу of геasons, inсluding сatеgtlrizingand сonsеrving divеrsity, as wеlI аs undеrstanding its oгigitls'

181

182

Тhе Pаttеrп апd Prс-lсеss of S1lесiаtkп dеfining spесiеsas disсrеtе Ьiologiсal еntitiеs is еssеntialto our undеrstandirrg of thе pr
ТаЬlе 2. IsolatingЬarriе Тyp. Prеmating

Есolо

Tеmр

Рolliл

Thе Naturе of IsolatingBarriеrs Thе importanсе of isolating Ьarriеrs is nеarly univеrsal rеgardlеss of thе spесiеsсonсеpt Ьеing appliеd. Although thе link Ьеtwееnrеproduсtivе isolation and tlrе BSС, whiсh dеfinеsspесiеson thе Ьasis of Ьаrriеrs to intеrЬrееd. ing, is сlЬviсlus,isoiatirrg Ьarriеrs also providе thе mеans through whiсh pсlpulatiсlrrsЬеgin to divеrgс through dесrеasеdgеnе flow, thе first stеp in spесiation. Thus еvеn m()rе Proссss-oriеntеdсonсеpts may Ье linkеd indirесtly tO thе еffесtsof isolating Ьarriеrs Ьесausеthеsе Ьarriеrs may at somе pсlint play tr rolе in сеssationсlf gеnе flow Ьеtwееnеvolutionаry linеagеs' Thеrе аrе nuпlеrous Ways to сlassify isolating Ьагriеrs;htlwеvеr' onе of thе rnost widеly usеd divisions is Ьеtwееn prеmаting and postmating bаrriеrs. Thеsе Ьаrriеrs inсludе thosе that arе duе to ехtrinsiс faсtors, suсh as есologiсal сlr Ьеhaviоral rтесhanisms, and thosе that arе duе to intrinsiс faсtors, suсh as еgg/spеrminсompatiЬilitiеs сlr gеnеtiс inсоmpatiЬilitiеs Ьеtwееn hyЬrid gеntlmеs(TaЬlе 2). Prеnlating Ьerriегsinсludе thosе thаt prеvеnt or dесrеаsеthе likеlihood of mating Ьеtwееn taхa. In еffесt, prеmating Ьarriеrs prеvеnt taхa (or thе gamеtеs from thosе taхa) from mееting.In есologiсаl isоlation potеntial mаtеs dtl ntlt meеt Ьесausеof diffеrеnсеsin haЬitat usе. For ехamplе, many insесts arе lirnitеd to fееding, сourting, mating' and ovipоsitioning on spесifiс plant hosts. Thus diffеrеrltspесiеserе prеvеntеdfrom intеrЬrееdingЬy thе rеstriсtion of сaсh ttl а spесifiсhost plant (Futuyma et a|. 1994). Altеrnativеly,indi. viduals may Ье tеmporally isolatеd' diffеring in thеiг timing of rеproduсtion. For ехamplе, thе sympatriс сoral spесiеsМoпtаstrаеа tlппulаris, М. fаuесllаtа, and М. frапksi arе tеmpoгally isolatеd through diffеrеnсеsin pеak spawning timеs, and diffеrеnсеs сlf only 1 to 2 hours Ьеtwееn spawning еvеnts providе еnough timе to dilutе gamеtеsand prеvеnt intеrspесifiсhyЬridization (Knowlton еt al. |997).In othеr сasеsindividuals of diffеrеntspесiеsmay Ье prеsеnt at thе sаmе timе and plaсе arrd still avoid intеrЬrееding.Pollinator isolation is tlnе suсh mеthod. Сharaсtеrs suсh as flowеr shapе,rеwагd (pollеn vеrsusnесtar), and сolor attraсt diffеrеnt typеs of pollinators (е.g.,moths' bееs, hummingЬirds) that rrray prеfеrеntiallvvisit only сеrtain flowеr tуpеs, еnsuring thаt pоllеn is trarrsfеrrеdonly within а spесiеs. A {inаl typе of ехtrinsiс isсllatingЬarriеr rеliеs Ol-lЬеhavioral diffеrеnсеsas prеmаting Ьаrriеrs.Сlosеly rеlirtеdspесiеsoftеn diffеr in partiсular traits thаt funсtion as signirls in thе mating proсеss. Thr-rsеvеrrspесiеsthat ехhiЬit no

Bеha. Postmating, prеzygotlс

Месh

Еgg-s

Сonsp prесе

Postmating, postzygotiс

HyЬri HyЬri

Dесrе fitnеss

othеr pre- or postmatil Ьrееding) may avoid int ing signals that rеstriсt ЕlaЬoratе malе ornamе rеlаtеd spесiеs аrе oftе (Andеrsson 1994), Dеspitе thе inhеrеnt mating at thе outsеt' m. pеn Ьoth prе- and postz in taxa with postmatinl plaсе. For еxamplе, in

Tbе Pаttеrп аnd Рroсess of Speсiаtion :iеsis еssеntiаlto our undеrstandаttеrnsof Ьiologiсal divеrsity. No lеsеpurposеs.Еvolutionаry Ьiolohеir quеstion with rеgard to thе istoryof thеir organism of intеrеst, еstto thе sсllvingof that partiсulаr

TaЬlе2. IsolatingЬarriеrs(Ьothprе- and postmаting)

Prеmating

Typе of Ьarriеr

Dеfinition

Есologiсalisolation

Spесiеsarе sеparatеdЬy diffеrеnt hosts or miсrohaЬitats.

Tеmporal isolation

Rеprоduсtion oссurs at diffеrеnt timеs. Di ffеrеnгspесiеsаttrасt diffеrеntpollinators,or pollеn of diffеrеnt spесiеsis сarriеd on diffеrеnrЬody parts.

Pollinator isolation

nеarly univеrsal rеgardlеss of thе rе link Ьеtwееnrеproduсtivе isola. ' thе Ьаsisof Ьarriеrsto intеrЬrееdlrovidе thе mеans through whiсh :rеаsеdgеnе flow, thе first stеp in rtеd сonсеpts may Ье linkеd indilесausеthеsеЬarriеrs may at somе Ь е t w е е nе v o l u t i t l n а г yl i n е a g е s . lating Ьarriеrs;howеvеr, onе of thе rеmatingand postmating Ьarriеrs. гo ехtrinsiсfaсtors' suсh as есologе that arе duе to intrinsiс faсtors, nеtiс inсompаtiЬilitiеsЬеtwееn hyг е v е n ro г d е с r е a s еt h е l i k е L i h t l o do Г g Ьarriеrsprеvеnt taхa (Or thе ga. есologiсalisolation potеntial matеs i t a t u s е .Е o r е x a m p l е .m e n y i n s е с t s rnd ovipositioningon spесifiс plant d from intеrbrееding Ьy thе rеstriс,ma еt al. 1994).Altеrnativеly,indiing in thеiг tirning of rеproduсtion. \oпtаstrаеааnпulаris, М. fаueolаtа, rough diffеrеnсеsin pеak spawning .s Ьеtwееnspawning еvеnts providе hyЬridizаtion (Knowlt intеrspесifiс s сlf diffеrеnt spесiеsmay Ье prеsеnt intеrЬrееding.Pollinator isolation is 'еr shаpе,rеward (pollеn vеrsus nес. pollinаtors(е.g.,moths, Ьееs' humo n l у с е r t a i nf l t t w е rt y p е s ' е n s u r i n g есlеs.

:г rеliеson Ьеhavioraldiffеrеnсеsas s oftеn diffеr in partiсulaг traits that ;. Thus еvеn spесiеsthаt ехhiЬit no

Postmating, prеzygotlс

Bеhavioralisolation

Bеhaviorsusеd as mаting signalsdiffег Ьеtwееnspесiеs.

Месhaniсal isolаtion

Spеrm transfеrсannot takе plaсе Ьесausеgеnitaliaarе not сompatiЬlе(or pollen doеs not adhеrе)Ьеtwееndifferent spесiеs. Propеrtiеs of thе gamеtеs (oftеnsurfaсеproteins)are not сompatiЬlеЬеtwееn spесiеsand prеvеnt fеrtilization. Hеtеrospесifiсspеrm arе outсompеtеd Ьy сonspeсifiс s p е r m 'r е g a r d l е sosf m a t i n g ordеr.

Еgg-spеrmrесognition

Сonspесifiс spеrm prесеdеnсе

Postmating, postzy8otiс

HyЬrid inviability HyЬrid stеrility DесrеasеdhyЬrid fitnеss

H y Ь r i d sd i е Ь е f o г еr е а с h i n g sеxual maturity. HyЬrids arе inсapaЬ1еof rеproduсing. HyЬrids havе lower fitness t h a n е i t h е rp a r е n t а sl p е с i е s and аге sеlесtеdаgаinst.

othеr prе- or postmating isolating Ьarriеrs (e.g.,sympatriс or synсhronous brееding)may avoid intеrЬrееding Ьесausе of prеfеrеnсеs for partiсular mating signalsthat rеstriсt thеir mating options to mеmЬеrs of a singlе spесiеs. ЕlaЬoratеmalе ornamеnts аnd сourtship displays that diffеr Ьеtwееnсlosеly rеlatеd spесiеs arе oftеn thought to rеsult in Ьеhаvioral isolating Ьarriеrs (Andеrsson1994\. Dеspitе thе inhеrеnt appеal of Ьarriеrs that prеvent diffеrеnt taхa from matingat thе outsеt' many isolating Ьarriеrs oссur postmating and may happеnЬoth prе- and postzygotiсally. As impliеd Ьy thе nаmе' mating may Oссur in taхa with postmating, prеzygotiс Ьarriеrs, but fеrtilization doеs not takе plaсе.For ехamplе, in Ьoth plants and animаls сonspесifiс spеrm (pollеn)

18З

184

The Pаtterп апd Proсеss of Spесiаtioп prесеdеnсеis сommonly fоund, whеrе, dеspitе multiplе mаtings, thе fеmalе (or fеmalе struсturе of plаnts) only irсссpts spеrm (or pсlllеn) from сon. spесifiсs, or, altеrnativеly, сonspесifiс spеrm outсompеtеs hеtеrospесifiсspеrm for fеrtilizаtion. Anita Diaz arrd Мark Maсnair (1999| studiеd сonspесifiс pollеn prесеdеnсеin thе monkеyflowеrs Мimиlus guttсltL|sand М. паsutus. Оn М. guttаtus сonspесifiс pollеn-tuЬе growth was fastеr than hеtеrospесifiс pollеn-tuЬе growth' еnsuring сorrspесifiсfеrtilization аnd сonfеrring rеproduсtivе isolation Ьеtwееnthеsе spесiеs. Postmating' postzygotiс Ьarriеrs rеprеsеntа finiri сatеgory of isolating Ьаrriеrs. Although this is a fairly сOп1monmесhanism of rеproduсtivе isolаtion, Dаrwin Wаs сonсеrnеd with this isolating Ьirrriеr Ьесausеit is thе Ьasis for thе produсtion сlf stеrilеhyЬrids. His dilеmmа, simply statеd,was this: if two taха еvolvеd from a сommon anсеstor' how сould thе сomЬination of thеsе .Would taхa form a stеrilе hyЬrid? that not imply stеrility аt somе timе in thе еvolution of tахa anсеstralto prеsеnt-dayspесiеs?Today wе know, howеvеr, that although hyЬrid stеrility is oftеn an important isсllаtingЬarriеr, it is far frсlm thе only form of postzygotiсisolation, and a Ьеttеrundеrstandingсlf gеnеtiсs has yiеldеd a solution to Darwin's proЬlеm of stеrilе hyЬrids. As with thе study of many еvolutionary proсеssеsin Ьiology, Drosophilа spесiеs havе provеd еxtrеmеly usеful in undеrstandingpostzygotiс Ьаrriеrs. In a сlassiс study of postzygotiс Ьаrriеrs, Alfrеd sturtеvаnt (1920) showеd that сrossing D. mеlапogсlsterfеmalеs with malеs of thеir sisгеr spесiеs D. simulаns yiеldеd only fеmalе hyЬrids, witlr malеs dying at thе larval to pu. pal transition. Мorеovеr' thе rесiproсal сross gavе risе to only hyЬrid mаlеs bесausеthе fеmalеs diеd as еmЬryos. This study providеd not onlY еvidеnсе of postzygotiс barriеrs to hyЬridizаtion Ьut also еvidеnсеthat thеsе Ьarriеrs сan appеar at diffеrеnt dеvеlopmеntalstagеs,that thе dirесtion of thе hyЬrid сross сan bе influеntial, and that hyЬrid inviaЬility сan span thе rаngе from partial to сompletе (Сoynе and Orr 2004). Although thе postzygotiс Ьarriеrs just disсussеd providе еvidеnсе of thе variеty of intrinsiс postzygotiсinсompatiЬilitiеs,thеy givе us only a rudimеntary undеrstandingof thеsе Ьarriеrs аnd thеir rеlationship to spесiation;that is' thеy tеll us what might happеn' Ьut not why or how thеsе Ьаrriеrs еvolvе. For that, Wе must turn to gеnеtiс modеls of postzygotiс isolation. Darwin Was unawarе of gеnеs or gеnе intеrасtions,Ьut his сonсеrn aЬout stеrilе hyЬrids was onе that trouЬlеd еvоlutiсlnaryЬiologists for somе tiпrе. Thе quеstion of how two spесiеs сan еvolvе from а сommon anсеstor yеt' whеn matеd, form stеrilеhyЬrids without at lеast onе of thсlsеspесiеspassing through a maladaptivе form was quitе pеrplехing.A solution to this dilеmma is providеd Ьy thе DoЬzhansky-Мullеr n-rodеl(although, аs notеd Ьy orr 11996]' Batеson еssеntiаllysolvеd this samе prсlЬlеm 25 yеars еarliеr). Thе solution dеpеnds upon undеrstandingthat gеnеtiс inсompatiЬilitiеsthat lеad to unfit offspring mаy Ье amеlioratеd Ьy mr.rltiloсr.rs intеraсtions.ln thе simplеst modеl, сonsidеr two loсi, AABB (Figurе З). In сlnе spесiеs a mutation сausеsthе ..а'' allеlе to appear and Ьессlmеfiхеd, rеsr-rlting in thе аaBB gеno. typе. In thе sесond spесiеsa mutation lеads to a ,.Ь'' аllеlе (again Ьесoming

/

(speсies2) AAbI

I

AABT \

Figurе З. Thе DoЬzhansky dеmonstrаtеs how spесiat intеrmеdiatе hyЬrid stagе. that possess thе variant allr taхon rеsults in spесiatron inсompatiЬlе' mating Ьеtw inviaЬlе, or othеrwisе lеss ] gеnе intеrасtion сomеs fro

fiхеd) and thе AAЬЬ gеn with thе anсеstral allеlе (с spесiеs nееd pass througl and ..Ь', allеlеs arе inсom d i f f е г е n tl i n е a g е sm а t е 'p r еrwisе lеss fit) Ьесausе tl baсkground, arе inсompа thоugh this proсеss may s mating barriеrs among multiloсus gеnеtiс inсomр Anothеr important arеа obsеrvation Ьy J. B. S. H with two diffеrеnt sеx сhr malеs, ZW, in Ьirds) is tht aЬility. Сallеd Haldanе's rl in a variеty of taxa (Сoy еrogamеtiс. Flaldanе's ru postzygotiс isolation (Сoy

Thе Pаttеrпаnd Processof Speciаtiott 1 8 5 эitе multiplе mаtings, thе fеrrrаlе )ts spеrm (oг pollеn) from сonoutсompеtеslrеtеrospесifiсspеrm rсnair (1999) studiеd сonspесifiс шlus gltttаtusand М. nаsutцs. Ол h was fаstеr than hеterospесifiс . r t i l i z n t i о lаl n d с o n Г с r r i l ] gr е p r ( ) . t a finаl сatеgoгуof isolirtingЬarhаnism of rеproduсtivе isolation, ЬzrггiеrЬесausеit is thе Ьasis fоr та, simplv statеd,was rhis: if two л.,сould thе сomЬination of thеsе irrrрlystеriIityаt somе timе in thе pесiеs?Today wе know, howеvеr, lportаnt isolating baгriеr, it is far ' and а Ьеttеrundегstandingof gе.oЬIеrnof stеrilеhyЬrids. proсеssеsin Ьiology, Drosсl|lhilа ldеrstandiпgp()stzygotiсЬarriеrs. Alfrеd Sturtеvarrt(1920) showеd l i r h m e | е so f r h t ' i r s i s г е r s p е с i е s itlr malеsdying аt thе l:rrvalto puOssgavе risе to only hyЬrid malеs study providеd rrot only еvidеnсе rt аlso еviсiеnсеthat thеsе Ьarriеrs еs' that thе dirесtiсlnof thе h,vЬrid tviaЬilityсan spаn thе rangе from disсussеdprovidе еvidеnсе of thе ilitiеs,thе1,givеtrsrlnly a rudilrrеnttt spесiation;that rеir rеlatilvе. lf postzygotiсis
(inviable/steri le hybrid) AaBb

/

\

(speсies 2) AAbb

A A B B (speсies1)

tI

Т AABb

\

AaBB

/

AABB (аnсestrа| spесies)

Figurе3. Thе DoЬzhansky-Мullеr modеlof irrtrinsiс postmating isolation dеmonstratеs how spесiаtionсould proсееdunhindеrеdЬy a dеirimental

intегmеdiatе hyЬrid stage.Тhe anсеstralspeсiеsdivеrgеsinto two sеParatеtaxa thatpossеssthе vаriant allеlеs..a',аnd ..Ь.''Fiхation of thе nоvеl аlЬlеs in еaсh taхonrеsultsin spесiаtion(spесiеs1 and spесies2). Sinсe..a'' and ..Ь'' arе inсompatiЬlе, mating Ьеtwееnthе two spесiеsrеsultsin a hybrid tlrat is stеrilе' inviaЬlе,oг othеrwisеlеssfit thаn thе parеntalspесiеs.Support for this modеl of geneintеraсtionсomеs from str"rdiеs с>[Drosophilа (Сoynе and orr zo04).

fiхеd) аnd thе AAЬЬ gеnotypе. In еithеr саsе thе nеw allеlе is сompаtiblе with thе anсеstralallеlе (е.g.,Ьoth AaBB and AABЬ arе viaЬlе). Thus nеithеr speсiеsnееd pass through a sеlесtivеlydеtrimеntal stаgе' Howеvеr, thе..a'' and ..Ь'' allеles arе inсompatiЬlе whеn thеy сo-oссur. If individuals from thе diffеrеntlinеagеsmatе, produсing an AaBЬ hvЬrid, it сould Ье stеrilе (or oth. еrwisеlеss fit) bесausе thе..а'' and..Ь'' allеlеs, whеn in thе samе gеnеtiс baсkground' arе inсompatiЬlе and form a postmating isolating Ьarriеr. Althoughthis proсеssmаy sееm unlikеly, multiplе еxamplеs,еspесiallyin post. mating barriегs among Drosophilа spесiеs, show that thеsе typеs of multilосusgеnеtiсinсompаtibilitiеsrnаy in fасt Ье quitе сommoп (orr 1995). Anothеr important arеa of study in postzygotiс isolation has foсusеd on an oЬsеrvаtionЬy J. B. S. Нaldanе (1922) that thе hеtеrogametiсsеx (thе onе with two diffеrеnt sех сhromosomеs, suсh as mаlеs, ХY, in mammals, and fеmalеs,ZW, in Ьirds) is thе onе most OftеnaffесtеdЬy hyЬrid stегility or inviaЬility.Сallеd Haldanе's rulе, this oЬsеrvation has сonsistеntly Ьееn supportеd in a variеty of taхa (Сoynе and orr 20О4| regardlеssof whiсh sех is hеtеrogamеtiс.Haldanе's rulе appеars to funсtion еarly in thе еvolution of postzygotiсisolаtion (Сoynе and orr 2004), sinсе rеlativеly rесеntly divеrsеd

1 8 6 Тhе Pаtterп апd Рroсеss rlf Speсiаtiott taхa arе morе likеly to еxhiЬit Нaldanе's rulе; сlldеr taхa oftеn show svmmеtriс hуЬrid proЬlеrns that аffесt Ьorh sехеs. Although Haldаnе's rulе has primarilv Ьееn oЬsеrvеd to rеsult in hybrid stеrility or inviaЬility of thе hеtеrogamеtiсsеx, soпlе еvidеnсе suggеststhat hеtеrogamеtiсhyЬrids rтay suffег dесrеasесlfitnеsstlrrough a variеty of othеr mесhanismsas wеll. For ехaпrplе,Nеal Daviеs anсl ссlllеaguеsshowеd tlrаt in thе Nеotropiсаl Ьuttеrflies Aпаrtiа fаtimа and А. аmаtbеа strong assсrrtlrtivе mating оссurrеd within еaсh spесiеs'Ьur whеn thеy wеrе сrossеd artifiсiаlly, fеmalе hyЬrids showеd геduсеd tЪrtiiity,сonsistеrrtwith Наldanе's rr-rlе(tЪmalе Ьuttеrfliеs arе hеtеrogаnlеtiс;Dаviеs et aI' 1997). In addition to this morе typiсаl rеsult,howеvеr,hyЬrid fеmalеsfrom thе А. аmаtbеа (fеmalе)xА. fаtitпа (malе) сross showеd а rеdr'rсеdtеnсlеnсyto miltе (Dаviеs et a|. 1997), Тhis study providеs еvidеnсеthat Haldarrе'srulе mzryеxtеnd Ьеyond thе typiсal oЬsеrvation of hyЬrid stеrility or inviaЬility, and that hyЬrid {itnеssmay Ье dесrеasеdthrough Ьоth prеmating and postmаting Ьarriеrs' A сomplеtе gеnеtiс undеrstаndingof postzygotiс isоlating Ьаггiегsis n.rцсh mоrе сomplеx than Нaldanе's гulе alоnе impliеs. Of partiсular intеrеstis thе сonсеpt of speсiаtirл gеnеs. Speсiation gеnеs arе gеnеs that diffеr Ьеtr-l,ееn taха and саusе rеproduсtivе isolation Ьеtrvееnthеn-r.A gеnе саllеd Оd1,55g'', for ехamplе, shows еvidеnсеof rapid еvolution in sсrmеfruit fliеs,dеspitеrеlativеly slow еvolution in other organisms. This gеnе appеars tсl Ье rеsponsiЬlе for stеrility in hyЬгid malеs ЬеtrvеenD. simцlаlusаnd D. mouritiапa (Ting еt al. 1998). Likе oсlysseиsJЕ]еnеsthat ехpеriеnсеrаpid еvolшtion(аt lеilst in somе taхa) may Ье likеly to саusе gеnеtiс inсompatiЬilitiеsЬеtwееntaхa and thus Ье good сandidatеs for spесiation gеnеs.МuсЬ of thе wсrrk сln sPесlation gеnеs rеmains thеorеtiсurl; howеvеr, еvolutiоrr:rгyЬiоlogists аrе addrеssing ехсiting quеstiorrssuсh as whеthеr partiсulaг gеnеs arе gеnеrally rnorе likеly to lеad to rеproduсtivе isolation, or whеthеr gеnеsassoсiatеdwith сеrtain funсtions arе Ьеttеrсаndidatеsfor spесi:rtiоngеnеsthаn tltlrеrs.

Thе Proсеssof spесiation Еvolutionary mесharrismssuсh as natural sеlесtion,sехual sеlесtion,and gеnеtiс drift сan promotе diffеrеrrсеsЬеtwееn populations in phеnotypеs and thеir undегlying gеnotypеs'еvеl1to thе ехtеrrtthаt diffеrеnt ;lopuiatiorrsЬесomе fixеd for сontplеtеly diffеrеnt аltеrnativеs. Why, thеn, is not еvеry сlеarly diffеrеntiatеdpopulatiсln соnsidеrеd a diffегеnt spесiеs?Thе сruх of thе proЬlеm геsts on two issuеs.First' htl.,vmuсh gеnе flow сlссurs Ьеtr-l,ееn diffеrеntiасingpopulаtions? Gеnе flow :rсtsto honrоgеnizеpopulatiorrs both phеnotypiсally and gеnеtiсally;hеnсе it works against sеlесti
сomplеtе thе spесiatron ovеrlap in gеographiс rar sеrvе а5 а strong Ьaггiе whosе ranges ovеrlap (sу or whеn prеviou.slyisoll o n d а r y с o n t a с t ) 'i n t r i n s Ьrееding Ьесomе nесеs importanсе of rеproduсt of spесiation' and muсh с е n t е r е do n r h е m е с h a n i Ьеtwееn spесiеs' Сlassiс modеls of thе s bution of populations un gеographiс isolation to t} d е g г е е o f g е r t g r а p Ь i сs е р an important сontriЬutol of spесiаtion havе foсus (natural sеlесtion,sехual d i v е r s if i с а r i o n e n d s p е с i а тHЕ RoLE oF NA

Thе imрortanсе of adapt lсlgicаl spеciаtioп) Was fil in thе 1940s in dеsсriЬin liеvеd that spесiаtitlnin I divеrgеlrt physiologiсa1сr m е n t s .Е г n s г M а y r \ | 9 4 2 latеd gеnеtiс diffеrеnсеs a n d е с о | o g i с e la d e p t a г i o rеproduсtivе isolating mt duсtivе isolаtion is thе dri allopatriс spесiation (FigL Nl[orе rесеntly thе impо d u с t i v е i s o l а г i o nе i t h е ri n аn important rоlе foг natr Ьесomе сlеar. LaЬoгator1 havе сoпfirmеd tlrat есo thаr rzrisеdfruit fliеs (D. l vironmеnts (varying tеml s o m е l е v е l o f p r е n t a t i n gl in diffеrеr-rtеnvironmеnts dеpеndеnt linеs raisеd in s r г а t еh o w t h е p r r l с е s sm i In thе simplеst modеl еvolvеs Ьеtwееrr popuiati

Тhе Pаttеrn апd Рroсess of Spеciаtioп гulе;oldеr taхa oftеn show sym)ееnoЬsеrvеdto rеslllt in hyЬrid sех' somе еvidеnсе suggеststhat l fitnеssthrough a variеty of othеr liеs and сollеaguеsshowеd that in n d А . а m а t h с аs t r o n g a s s o r t а t i v е hеn thеy wеrе сrossеd artifiсiurlly, эnsistеntwith Haldanе's rulе (fееt a|. 1997). ln addition to this from thе А. аmаthеа(fеmalе)x А. еnсy to matе (Daviеs et a|. 1997). s rulе may ехtеnd Ьеyсlnd thе typЬility,and that hyЬrid fitnеssmаy эostmаtingbarriеrs. tzygotiсisolatingЬarriеrs is muсh npliеs.of partiсular intеrеstis thе nеs arе gеnеs that diffеr Ьеtwееn ееnthеm.A gеnесallеd odysseиs, tion in sоmе fruit fliеs, dеspitе rеlТ h i s g е n еa p p е а r st o Ь е r е s p o n s i simulаns and D. mаuritiапа (Тtng еriеnсеrapid еvolution (at lеast in nсompatiЬilitiеsЬеtwееntaхa and rеs.Muсh of thе work on spесiаrolutionaryЬiсllogistsarе аddrеssrrtiсulargеnеs arе gеnеrally morе whеthеrgеnеsassoсiatеdwith сеr:сiationgеnеsthan othеrs.

sеlесtion,sеxual sеlесtion,and gееn populations in phеnotypеs and tеnt that diffеrеntpopulаtions Ьегnativеs.Why, thеn, is not еvеry : d а d i f f е r е n ts p е с i е s ?Т h е с r u х o f w muсh gеnе floш,oссurs Ьеtwееn :s to homogеnizеpopulations Ьoth lorks against sеlесtion and drift in ;iation, rеspесtivеly.Sесond' how е is thorniеr and points to thе imэесiatioпproсеss.Although divеrgnsiс barriеrsto rеproduсtion, somе Ье prеsеnt to stop gеnе flow and

сomplеtеthе spесiation proсess. For allopatriс populations' whiсh do not ovеrlapin gеographiс rangе' thе physiсal distanсе imposеd Ьy gеography сan sеrvеas а strong Ьarriеr to gеnе flow. Нowevеr, for divеrging populations whosеrangеsovеrlap (sympatry)or arе adjасеnt to onе anothеr (parapatry), or whеn prеviously isolated allopatriс pоpulations сomе into сontaсt (sесondaryсontaсt),intrinsiс or ехtrinsiс Ьarriеrsto gеnе flow that prеvеnt intеrЬrееding Ьесomе nесеssary to сomplеtе thе spесiation proсеss. Thus thе importanсеof rеproduсtivе isolating Ьarriеrs has Ьееn paramount in studiеs o{ spесiation,and muсh of our undеrstandingof thе proсеss of spесiation is сеntеrеdon thе mесhanisms that favor thе еvolution of rеproduсtivе isolation bеtwееnspесiеs. Сlassiс modеls of thе spесiation proсеss foсusеd on thе gеographiс distriЬutionof pоpulations undеrgoing divеrgеnсеаnd thе rеlativе сontriЬution of gеographiсisolation to thе formation of nеw spесiеs(Figurе 4). Although the dеgrеeof geographiс sеparation Ьеtwееn divеrging populаtions is сеrtainly an important сontriЬutor to thе disruption of gеnе flow, morе rесеnt studiеs of spесiationhavе foсusеd on thе importanсе of еvolutionary mесhanisms (naturalsеlесtion,sеxual sеlесtion,gеnеtiсdrift, and mutation) in promoting divеrsifiсationand spесiationеithеr in allopatry or in sympаtry. тHЕ RoLЕ oF NAтURAL sЕLЕстIoN lN sPEс|AтloN Thе impоrtanсе of adaptivе divеrgеnсе in thе spесiation proсеss (tеrmеd eсologiсаlspесiаtioп)was fiгst notеd Ьy thе gеnеtiсistThеodosius DoЬzhansky in thе 1940s in dеsсriЬing spесiation in Drosophilа. DoЬzЬansky (1946) Ьеliеvеdthat spесiation ln Drosophila oссurrеd mаinly through thе еvolution of divеrgеntphysiologiсal сomplехеs that wеrе suссеssful in diffеrеnt еnvironmеnts.Еrnst Мaуr (1942) Was thе first to point out that many of thе ассumulatеd gеnеtiс diffеrеnсеs Ьеtwееn populations' partiсularly in physiologiсal and есologiсaladaptations to partiсular еnvironmеnts' Wеrе also potеntially rеproduсtivеisolating mесhanisms. Suсh ..Ьy-produсt'' еvolution of rеpгoduсtivеisolation is thе driving forсе Ьеhind Мayr's сlassiс modе оf viсarianсе allopatriсspесiation (Figurе 4). Morе rесеntlythе importanсе of есologiсal divеrgеnсеin promoting rеproduсtivеisolation еithеr in allopatry or in sympatry has Ьееn rесognizеd, and an importantrolе for natural sеlесtionin a variеty of routеs to spесiationhas Ьесomесlеar. LaЬoratory ехpеrimеnts (rеviеwеdin Riсе аnd Hostеrt 1993) havе сonfirmеd that есologiсal spесiation сan oссur; ехpеrimеntal studiеs that raisеd fruit fliеs (D. melаnogаstеr or D. psеudoobsсurа) in diffеrеnt еnvironmеnts(varying tеmpеraturеsor food sourсеs) havе dеmonstratеd that somе lеvеl of prеmating rеproduсtivе isolation еvolvеd Ьеtwееn linеs raisеd in diffеrеntеnvironmеnts,whilе no prеmating isolation еvolvеd Ьеtwееn indеpеndеntlinеs raisеd in thе samе еnvironmеnt. Thеsе ехpеrimеnts dеmonstratеhow thе proсеss might also work in naturе. In thе simplеst modеls of есologiсal spесiation, rеproduсtivе isolation еvolvеsЬеtwееn populations inсidеntally as a Ьy-produсt of adaptation to

187

188

Тhе Раttеrп tlпd Prсlсеssrlf Spесiаtklп

Viсаrianсe AlIopatriс

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PeripheraIlsoIаtesor Founder Еffeсt

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Sympatriс

altеrnativе sеlесtiоn rеgrп tivе isolation has Ьееn rе1 Thesе Ьirds arе onе of th and havе evolvеd an im1 funсtion, in ассordanсе v havе сomе to oссupy. Lo (Grant et aL. 1976) ar'd tl Darwin's finсhеs has еvo spondеnсе to сhanging ес i n t е r s p е с6i с с o m p е t i r i o n tions Ьеtwееn Ьеak morp n е n г o f m a t i n g s i g n a l si n bеhavioral rеproduсtivе i D a r w i n . s f i n с h е s .T h е p г (pitсh) and tеmporаl pr с h а n g е s i n Ь е a k g a p е ;h . vary as a funсtion of Ьеа thе struсturе of song aп finсhеs on Santa Сгuz Is Ьеaks adaptеd foг сrushiл I o w е г г a t е s o f s y l l а Ь l еr е sресiеs with smallеr Ьеak сausе song plays a сеntra this linkagе Ьеtwееn Ьеak its сonсomitant influепсе plеs of Ьy-produсt еvolut portanсe in spесiаtion of

PARALLЕL sPЕс|l oF ЕсoLoG|сAL l

I-.igr-rrе 4. Сlassiс modеls (сlr rтodеs) tlf spесiatitln аrе Ьasеd on thе dеgrее of gеographiс sеpаration аs tЬе driving foгсе of spесiation. In viсarianсе allopаtry, аnсеstrаl pоpulations of a onсе-сontinuous, largе rangе of a spесiеs аrе sеparatеd Ьy а viсаriаrrсе еvеnt (е.g.,mountains, rivег, oсеan). Diffеrсnсеs in еnvironmеntal сonditions on еithеr sidе of thе Ьarriеr to dispеrsаl pronrotе loсal adaptation and Ьy-prсlduсt rеprtlduсtivе istlliltion, 1еadingto thе formаtion сlf nсw spссiсs (Мayr 1942). Thе pеriрhеral-isolatеs or foundеr-еffесt modеl of spесiatiсln p()stulаtеsgеnеtiс drift as thе prirтаry mесhаnism that prсrmotеs divеrgеnсе аnс1spесiаtion. Pеriphеral isolatеs or foundеr сvеnts rlссur whеrt ехpirrrd Outward from thе еdgеs of thеir distriЬutions to OссuPy рсlpr.rlatiсlr.rs dispеrsе to а nеW loсatior-r nеw l-raЬitats,сrr lvhсn ir sп.ral]numЬеr of ir-rdividLrаls аnd еstаЬlish a nеw population. Мayr (1954) prtlpсlsесithat gеnеtiс сhangе

ParallеIеvolution of sim ronmеnts strongly impliс s p е с i a t i o n с а n r е s u I tf г o n produсtivе isolation that rеlatеd populations as a t

would Ье rapid in suсh fou сould rеsult in gеnеtiсrеor i s o l a t i o na n d r е s u l ri n r a p i prrpulationsthat ovеrlаprn spесiationwhеrе rеproduс not geographiсallysеparat aссompaniеd Ьy assortativ

Thе Раttеrтlапd Prсlcеssof Spесiаtion altеrnativеsеlесtionгеgimеs.A rесеnt ехamplе of suсh Ьy-produсt rеproduсtivеisolation has Ьееn rеportеd irr Darwin's finсhеs of thе Galdpagos Islands. ThеsеЬirds arе onе of thе most сеlеbratedillustrations of adaptivе radiation and havе еvolvеd an imprеssivе 21rraуof spесializations in Ьеаk form and funсtion, in aссordanсе with thе divеrsе fееding niсhеs that diffеrеnt spесiеs havесomе to oссupy. Long-tеrm fiеld studiеs Ьy Pеtеr and Rosеmary Grant (Gгаrrtеt aI. 1'976)and thеir сollеaguеs havе showrr thаt Ьеak morphology in Dаrwin's finсhеs hаs еvolvеd Ьy nrеans of natural sеlесtion in prесisе сorrеspondеnсеto сhanging есologiсal сonditions, inсluding food availaЬility and intеrspесifiссompеtition. Jеffrеy Podos (2001) tеstеd for potеntial сorrеlations bеtwееn Ьеak morphology ar-rdsong struсturе. Song is a major сomponеntof mating sigrralsin Ьirds, and diffеrеnсеsin Ьirdsong lеad to prеmаting bеhаvioralrеproduсtivе isolation in a variеty of spесiеs of Ьirds, inсluding Darwin's finсhеs. Thе produсtiоn of Ьirdsongs with variation in frеquеnсy (pitсh) and tеmporal propеrtiеs (е.g., syllаЬlе rеpеtitions) rеquirеs rapid сhangesin Ьеak gapе; hеnсе voсal pеrformanсе сapaсitiеs arе prеdiсtеd to vaгy as a funсtion of Ьеak morphology. Podos tеstеdthis idеa Ьy сompаring thе stгuсturе сlf song аnd Ьеak Inoгpholog1'in еight spесiеs of DarwinЪ finсhеson santa Сruz Island (Figurе 5). Hе found сhаt spесiеs with largе Ьеaksadaptеdfor сrushing hard sееdshаd еvolvеd songs with сomparativеly lowеr rаtеs of syllaЬlе rеpetition and narrowеr frеquеnсy rangеs than thosе speсiеswith smallеr Ьеaks еvolvеd for fееding on smallеr, softer sееds. Bесausеsong plays ir сеIrtralrolе in rеPгoduсtivе isolation in Darwin's finсhеs, this linkagе Ьеtwееn Ьеak morphоlogy sеlесtеdfor fееding pеrformanсе and its сonсomitant influеnсеon song struсturе illustrаtеs onе of the Ьеst еxamplеs of Ьy.produсt еvolution of rеproduсtivе isolation and its potеntial importanсеin spесiatiоnof Darwin's finсhеs. PARALLЕL sPЕсIAт|oN As A s|GNAтURE oF ЕсoLoGIсAL sPЕс|AтIoN

ation аrе Ьasеd on tlrе dеgrее сlf Е spесiation.In viсarianсе allopatry, larее rangе of a spесiеs arе rins, rivеr, oсеan). Diffегеnсеs rn nе bаlriег to dispеrsal pronlсrtе loсal . r г i t l п l' е l d i n g t o t h е [ o r m а t i о n o Г )lirtеsor frlundеr-еtfесtmodеl оf r.rаrymесhаnism that рromotеs 's or foundеr еvеnts oссur whеt-t ; rlf thеir distriЬutirins to oссupy dividulrlsdispеrsеto i'1llеw loсаtion 1) pг
Parallеlеvolution of similar traits in populations that inhaЬit similar еnvitonmеntsstrongly impliсatеs natural sеlесtion аs i] сausativе agеnt. Pагаllеl speсiationсan rеsult from thе paгallеl еvolution of trаits that dеtеrn-linеrеproduсtivеisolzrtionthat еvolvе геpеatеdlyin indеpеndеntlydеrivеd, сlosеly rеlatеdpopulations as a Ьy-produсt of adaptation to diffеrеnt еnvironmеnts

wouldЬе rapid irr suсh founding ptlpulatiсlnsЬесausесlf gеnеtiсdrift. This сouldrеsultin gеr-rеtiс rеoгganizаti
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Figurе 5. An illustrаtionof Ьv-produсtrеproduсtivеisolirtionas a геsultof adаptivеdivеrgеnсеin Ьеak lnсlгphologyoссurs in Dаrlvill.sfinсhеs.Bеak morphologyand rеprеsеntаtivе sound spесtгogrаmsof solrgsfror.rr еight Dilrwirr'sfiлсh spесiеsotl SantaСгrrzlslаnd (frоm пry trl btltttlllt:Gеospizа tltаgпirostris,G. iortis' (}. Iuligiпоsа, С. sсапt]еlts'Сашаrhупсhus pаruиlus' С. psittасulа, С. pаllidа' С. tlliuасеа)arе shown. Sglесtrogrаmfгеquеnсy rеsolution,98l{ц sсalеЬ.lr,0.5s.Intеrspссifiсvаrrзгiсlrlis llppэrеntin Ьoth rr.r
Figurе 6. Parallеl spесiatio d е t е r m i n еr е p r o d u с t i v iеs o adаptation to diffеrеntеnv Ьеtwееn есotypes from thе (width inсrеasеswith inсrе Ьetwееndiffеrеntесotypе

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(Sсhlutегand Nagеl 1'995).Thе Ьеst ехamplеs of parallеl spесiation сomе from sympatriс spесiation еvеnts whеrе indеpеndеntсolonizations of partiсular еnvironmеnts havе lеd to similar, rеpеatеd pattеrns of сharaсtеr divеrgеnсе in adaptivе traits assoсiatеd with diffеrеnt niсhеs and thе parallеl Ьuildup of аssortativе mating Ьy selесtivееnvironmеnt Ьasеd upon diffеrеnсеsin thosе adаptivе trаits (Figurе 6). Thе thrеespinе stiсklеЬack (Gаsterostеus асuleаtus) Ьas Ьесomе a modеl systеmfor thе study of pаrallеl spесiation. Thе anсеstral thrееspinеstiсklеЬaсk is a marinе fish found aсross a widе gеographiс distriЬution from Alaskа and British Сolumbia through lсеland, Sсotland, Norway, and Japan. This spесiеsis аnadromous, Ьеing spawnеd in frеshwatеr strеams, spеnding thе juvеnilеstagе in mаrinе еnvironmеnts,nnd migгating Ьaсk to strеaпls as adults to Ьrееd. lndеpеndеnt сolonizations of strеam еnvironmеnts havе lеd to multiple strеam-rеsidеntstiсklеЬaсk populations that no longеr migratе to thе oсеan. In addition, in British СolumЬia and Alaska indеpеndеnt сolo_ nizаtionsЬy mаrinе stiсklеЬaсksof postglaсial frеshwatеr lakеs formеd aftеr thе rеtrеat of thе glaсiеrs at thе еnd of thе Plеistoсеnе havе lеd to thе indеpеndеntеvolution of lakе forms (Ьеnthiсsаnd limnеtiсs)in multiplе fгеshwatеr lakеs.Spесiationin stiсklеЬaсkshas involvеd thе rеpеаtеdсolonization of nеw еnvironmеntsand thе aссomparryingсhangеs in adaptations, primarily Ьody.sizеdiffеrеrrсеsand numЬеr and sizе of gill rakеrs (spinеs on thе gill p|аtеsusеd to 6ltеr food paгtiсlеs),аssосiatеdwith есologiсlrl diffеrеnсеsin еaсhеnvironmеnt.Havе thеsеadaptivе сhangеs lеd to rеproduсtivе isolation Ьеtwееndiffеrеnt stiсklеЬaсk есotypеs? In a rесеntstudy Jеffrеy МсKinnon and сollеaguеs(МсKinnon еt al. 2004) found strоng еvidеnсе of assortativе mating Ьy sizе through diffеrеntial fеmalе prеfеrеnсеsfor пralе Ьody sizе in altеrnativе strеam and mаrinе еnvironmеnts.

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luсtivе isolatitln as a rеsult of пrs in Dагlvin's finсhеs. Bеak ]granls сli songs fгсlrn еight ,from top tсl bottottl: (}еospiztt ldепs, Сdmdrhу пс b u,s1lаruulu s' rvn. Spесtrogram frеquеnсy с varilrtion is apраrеnt in Ьotlr largе Ьсaks (е.g.,G. mаgnirostris) rIowеr frеquеr-rсyfangеs thаn thosе (From Pоr-lсls2001.)

Figurе6. Parallеlspесiationсtrnrеsultfrom thе parаllеlеvolutionof traits that reproduсtivеisolаtionthаt еvolvеrepеаtеdlyas a Ьy-pгoduсtof dеtегminе adaptаtionto diffеrеnt еnvir
191

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Thе Pаttern апd Proсess of Spесiаtioп Anadromous marinе populations arе laгgеr in Ьody sizе than strеam-rеsidеnt populations, prеsumaЬly an advantagе in thе long-distanсеmigrations that marinе populatiоns undеrgo. Mating сompаtiЬility Was morе than tr,l,otimеs highеr whеn fеmalеs Wеге pairеd with malеs from thе sаmе есotypе (from British СolцmЬia оr Japan) than whеn thеy wеrе pairеd with malеs from a diffеrеnt есotypе. To tеst thе importanсе of Ьody sizе as thе Ьasis for аssortativе mating Ьy есotypе,МсKinnon and сollеaguеs(MсKinnon еt al. 2004) rеarеd stiсklеЬaсksfrom strеam-rеsidеntand marinе populations in thе laЬoratory and manipulatеd thеir Ьody sizеs Ьy сhаnging thе lеngth of thе growing sеason. This produсеd еithеr largе-Ьodiеd or small-Ьodiеd fish of Ьoth sеxеsin Ьoth mаrinе and strеam-rеsidеntесotypеs.In mating trials with thеsе ехpеrimеntally manipulatеd fish, thеy found that malеs and fеmalеs had highеr mating сompatiЬilitiеs whеn thеy wеrе matсhеd for sizе, rеgardlеsso{ their eсotypе of origin. Thеsе rеsults dеmonstratеthе importanсе of a singlе phеnotypiс trait, Ьody sizе, in adaptivе divеrsifiсation in stiсklеЬасks and suggеst that divеrgеnt natural sеlесtion on this trait in diffеrеnt еrrvirontnеnts also makеs a primary сontriЬution to rеproduсtivе isolation that lеads to spесiаtion.

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{ тHЕ RoLЕ oF NAтURAL sЕLЕстloN lN Hosт sHIFтs AND sYMPAтR|с sPEсlAт|oN Thе oссurrеnсеof sympatriс spесiation,spесiationwith
Figurе 7. Sympatriсspес faсilitatеdЬy host or haЬ divеrging phеnotypеs.Tl rеproduсtivеisolationеv ir-rdividuals tln thе nеw hr spесiationproсеsswithtl

primary сharaсtеristiсt host shifts in Rhаgolеtis Ьrееd on thе samе host spесiеs is low. For еxam ing еggs on applе trееs oviposition sitеs.This st Ьеtwееn hawthoгn and с u m u l a t е ds i n с еt h е i n i t nology, suсh as timing a d u l t s ( е . g . ,F е d е r 1 9 9 8 natural sеlесtion as thе fruiting phеnology Ьеtш diffеrеnсеs Ьy еaсh hos thе host raсеs and аugп еnсes. Thus thе Rhаgolс

Thе Pаttеrп апd Рroсеss of Speciаtioп in Ьody sizе than strеam.rеsidеnt гhе long-distanсеmigrations that а t i Ь i l i г yW e sm о r е t h a n t w o t i m е s lеs from thе samе есotypе (from y wеrе pairеd with malеs from a f body sizе as thе Ьasis for assor. ollеaguеs(МсKinnon еt al. 2004) .d marinеpopulations in thе laЬoсhanging thе lеngth of thе growJiеd or small-Ьodiеdfish of Ьoth otypеs.In mating trials with thеsе ind thаt malеs and fеmalеs had эrе matсhеdfor sizе, rеgardlеssof nstratеthе importanсе of a singlе ivеrsifiсationin stiсklеЬaсks and . h i st r а i ri n d i f f е r е nеt n v i r o n m е n t s lroduсtivе isolаtion that lеads to

Disruptive seleсtion

Assortativеmating within phеnotypеsor habitats

oN IN Hosт 'toN есiationwithout gеographiс isolaausе thе сonditions undеr whiсh эgеnizingеffесtsof gеnе flow wеrе сirсumstanсеs.Мorе rесеntly thе r с с o m p a n i е dh у s r r o n gа s s O r t а t i V е (Figurе7) as a likеly modеl for thе iеs has сonvinсеdmany еvolution, a n i m p o r t a n tа n d е v е n p r i m a r y 1anisms.lmpliсit in thе proсеss of геproduсtivеisоlation Ьеtwееn di. эrvе as thе primary Ьarriеr tO gеnе о p u l а r i o n so. n е с o m m o l l w a y i n dly еvolvе is through host shifts Ьy с i a l i z еi n p e r r i с u l а rh o s г s p е с i е s . . х а m p l еo f a s у m p а t r i сь р е с i а t i o n l i е s ( 1 9 6 6 ,\ 9 6 9 \ o f t h е h o s t r a с е s olеtis pomonеllа).HawtЬorn tгееs rthorn rасе of R. pomсlпеllа is tЬe tggot fliеs wеrе first disсovеrеd on dson Valiеy геgiсlnof Nеw York in ravе Ьееn studying diffеrеnсеs Ьеpplе raсе sinсе thе mid-1960s and ; diffеrеnсеsin lifе history and rеr Ьеtwееnthе two host rасеs. onе

Figurе 7. Sympatriс spесiation сan Oссur whеn disruptivе natuгal sеlесtton faсilitatеd Ьy host or hаЬitat shifts is aссompaniеd Ьy assortativе mating Ьy thе divеrging phеnotypеs. Thе sympаtriс modеl сlf spесiation rеquirеs that ..likе'' rеproduсtivе isolatiсln еvсllvеsаs a rеsult of аssortativе mating оf individuаls on thс nеw host or in thе nеw hаЬitat in oгdеr to initiatе thе spесiatiсlnpr()сеsswithtlut gеogrаphiс isolation.

primary сharaсtеristiсthat promotеs sympatriс divеrgеnсе assoсiatеd with host shifts tл Rbаgolеti.sand othеr phytophagous insесts is that thеy fееd and Ьrееdon thе samе host spесiеs;thus dispеrsal Ьеtwееn diffеrеnt host plant s p е с i е iss l o w . F о r е х a m p l е .f е m a l е so f h a w t h o r no r i g i n а r е a v е r s еt o o v i p o s i t ing еggs on applе trееs, whеrеas applе-origin fеmalеs prеfеr apple trееs for ovipositionsitеs.This strong host fidеlity limits intеrhost movеmеnt of adцlts Ьеtwееnhawthоrn and applе trееs. In addition, gеnеtiс diffеrеnсеs havе aссumulatеdsinсе thе initial host switсh that promotе сhangеs in Ьrееdingphеnology, suсh as timing tlf mating, pupation and diapausе' and есlosion of adults(е.g.,Fеdеr 1998). Thеsе сhangеs arе thought to hаvе Ьееn favorеd Ьy natural sеlесtionas thе diffеrеnt host raсеs of fliеs adaptеd to diffеrеnсеsin fruiting phеnology Ьеtwееnhawthorn аnd applе hosts. Suсh loсally adaptеd diffеrеnсеsЬy еaсh host raсе сontriЬutе to rеproduсtivе isolation bеtwееn thе host raсеs аnd augmеnt host fidеlity through fеmalе oviposition prеfеrеnсеs.Thus tЬе Rhаgolеris fliеs providе а fundamеntal ехamplе of есologiсal

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Thе Pаtterп аnd Proсеss of Speсiаtioп divеrgеnсеwhеrе сomplеtе gеogrаphiс isolation is not аlways rеquirеd to initiatе spесiation. Although phytophаgous insесts offеr sеvеral wеll-doсumеntеd ехamplеs of sympatriс spесiation though host shifts, a rесеnt study providеs at lеast onе ехаmplе of thе potеntial for sympatгiс spесiation via a host shift in a vеrtе. Ьratе' Afriсan indigoЬirds (gеnus Уiduа) arе host-spесifiсЬrood parasitеs, laying thеir еggs in thе nеsts of firеfinсhеs (gеnus Lаgonostiсtа)' and diffеrеnt indigobird spесiеs spесializе in pzrrasitizingdiffеrеnt spесiеs of firеfinсhеs.IndigoЬird nеstlings arе rеarеd along with thе host young and mimiс thе mouth markings of thеir rеspесtivе hosts, thus lowеring thе proЬaЬility of Ьеing rеjесtеdЬy thеir host fostеr parеnts.In addition to this uniquе mimiсry adaptаtion Ьy young indigobiгds, as adults, malе indigoЬirds mimiс thе song that is sung Ьy thеir host spесiеssirе, and fеmаlеsrеarеd by a spесiliс host spесiеsof firеfinсh prеfеrеntially matе with malе indigoЬirds that sing thеir natаl hostspесifiс song. This faсilitatеs host-assortativе mating and lеads to rеproduс. tivе isolation among diffеrеnt spесiеs of indigoЬirds that parasitizе diffеrеnt host spесiеs of firеfirrсhеs.A rесеnt phylogеnеtiс study Ьy Мiсhaеl Sorеnson and сollеaguеs(Sorensonеt al. 2003) that сomparеd n-litoсhondrialDNA sеquеnсеs for a numЬеr of diffеrеnt spесiеsof indigoЬirds and thеir rеspесtivе firеfinсh hosts dеnronstrаtеd that diffеrеnt indigoЬird spесiеs that parasitizе diffеrеnt firеfinсh hosts arе gеnеtiсally diffеrеntiatеd from onе anothеr, a finding сonsistеntwith assortativеmating of indigoЬirds rеarеd Ьy a partiсular firеfinсh host spесiеs.Thеse rеsults suggеstthat divеrgеnсеthrough loсal adaptations in nеstling mouth markings, adult nrаlе song сopying, and fеmalе prеfеrеnсеs for host spесiеs song typе has lеd to positivе assortativе mating Ьеtwееn diffеrеnt host-spесifiс spесiеs of indigoЬirds. This pattеrn of host-spесifiс adaptations linkеd with positivе assortativе mating within a host typе is сonsistеnt with sympatriс spесiation irr Afriсan indigoЬirds through host switсhеs in thе firеfinсh spесieswhosе nеsts thеy parаsitizе. RЕPRoDUст|VЕ lsolAтloN вY NAтURAL sЕLЕст|oN

MAY BЕ RE|NFoRсЕD

Natural sеlесtionсan aсt to dirесtly inсгеasеthе аmount of prеmating isolation bеtwееn two divеrging populations by sеlесting against hyЬrids formеd Ьеtwееn thеm. This proсеss' first proposеd Ьу Thеodosius Dobzhansky (19з7) and tеrmеd rеiпforcemeпlby Frank Blair (1955 ), сan oссur in arеasof sесondary сontaсt whеn prеviously allopatriс populations сomе into сontaсt and intеrЬrееd. Whеn hyЬrids Ьеtwееn formеrlу allopatriс populations arе partially infеrtilе, rеinforсеmеnt саn сomplеtе thе spесiation proсеss. Rеinforсеmеnt was а popular сonсеpt аftеr thе modеrn synthеsis Ьесausе it allows natural sеlесtion to drivе spесiatiоn dirесtly, Ьut its еmpiriсal dеmonstration has Ьееn diffiсult, and its ехistеnсе as an important сomponеnt of есologiсal spесiationhas Ьееn сontrovеrsiаl(е.g',Noor 1999; Мarshall еt al. 2002). Most of thе еvidеnсе for rеinforсеmеntсomеs fгсlm сomparisons Ьеtwееn allopatriс and sympatriс populаtions in thе strеngth of fеnralе mating

prеfеrеnсеsfor сonspесi of D rosolt h iltt psendoоlts luсtаlnсe to matе with ht populаtions (Noor 199.5 fеrtilе, allowing fсlr gеnе onе of thе Ьеst-doсtr t h i с a n d l i m n е t i се с o t y p е Ьaсk. Нoward Rr"rrrdlе: lаЬor21toryсrossеs anсl ir Ьrids suffеr a foraging d pаrеntal еnvironmеnts.It vironnrеnt with аrmplеас parеrrtal spесiеs.Horvеvе parеr-rtаlеnvironmеnt, lit ratеs :rnd wеrе smallеr at Wеrе pooгеr at саtсhing fiеld еnvironmеnts Ьесiru In adсlitiol-l' Ьеnthiс fеп likеly to matе witlr irrtеr malеs from al|opatriс pс sults support a modеl of t h r o u g l l n а t r l r а ls е | е с t i o fitnеss in еithеr parеntlll t How impoгtant h.rs rе Т h е p г t l Ь | е mi s t h l t r с i n pattеrns of strongеr divе tions. Imaginе that two s] grее of геprсlduсtivеisrll I i k е l vс o r l t i n u еt ( )с ( ) е х i s еls of геproduсtivе isolat or thе ехtinсtion oi thе spесiеs pairs) that wе ol еvolvеd a high dеgrееof following sесondаrv сoг v o l r ' е di n m a t i l l g с l с с i s i o dеrrrrinеsthе prосеssof rt рromotе divеrgеnсеirr rn must Ье tightlv linkеd wi ity. Tlrеsе геquirеmеntsп Thеsе argumеnts do nс plеting thе spесiatiсlnprс that thе еvidеnсе for tnе '

sivе. of thе two proсеssе rr'ith ссologiсel s1rgсiд1 rеinfoгсе:tтеnt-thе first i spесiation; thе irnpoгtаn

Тhе Pаttеrn апd Рroсеss o| Spеciаtiсtп 1 9 . t lation is not always rеquirеd to ini_ ',еrаlwеll-doсumеntеdеxamplеs of rесеnt study providеs at lеast onе есiation via a host shift in a vеftеаrе host-spесifiсЬrood parasitеs, (genusLа goпОstiсtа), and diffеrеnt 3 diffеrеntspесiеs of firеfinсhеs. In. rеhost young and nrimiс thе mouth ,wеringthе proЬaЬility of Ьеing rе:ion to this uniqце mimiсry adaptaindigoЬirdsmimiс thе song that is ; rеarеd by a spесifiс host spесies of ligobirds that sing thеir natal host. tivе mating and lеads to rеproduсndigobirds that parasitizе diffеrеnt gеnеtiсstudy Ьy Мiсhaеl Sorеnson .сonrparеdmitoсhondriаl DNA sеo f i n d i g o b i r d sa n d t h е i г r е s p е с t i v е t i n d i g o Ь i r ds p е с i е st Ь a t p a r a s i t i z е liffеrеntiatеd from onе anothеr, a o f i n d i g о Ь i r d sr е a r е dЬ y а p а г t i с u ggеstthat divеrgеnсе through loсal adult malе song сopying, and fеypе hаs lеd tо positivе assortativе :сiеsof indigoЬirds.This pattеrn of 'sitivе assortativеmating within a spесiation in Afriсan indigoЬirds :iеsц.hоsеnеstsrhеy pаrаsiгizе. r вЕ RЕ|NFoRсED

asе thе amount of prеmating isolaly sеlесtingagainst hybrids formеd 'osеd Ьy Thеodosiцs Dobzhansky k Blair (1955),сan oссur in arеas of rtriс populаtionsсomе into сontaсt Ъrmеrly allopatriс populations arе rplеtеthе spесiatiоn proсеss. Rеin: modеrn synthеsisbесausе it allows tly, Ьut its еmpiriсal dеmonstration important сomponеnt of есologiсal > o r1 9 9 9 ;М a r s h a l l e t a | . 2 О 0 2 ) . t сomеs from сomparisons Ьеtwееn n thе strеngth of fеmalе mating

prеfеrеnсеsfor сoгlspесifiсs.For ехirmplе, fеmalеs dеrivеd from populations of Drosсlphilа 1lseudotlbsсt,lrasvrrrpatriсwith D . persimilis сlisplay grеatег rеluсtanсеto nlatе with hеtеrospесifiсmаlеs than do fеmalеs 1rorn aIlopatгiс populations(Noсlr 1995)' F1 hyЬrid malеs arе stегilе,Ьut hyЬrid fеmalеs arе fеrtilе,allowing fсlr gеnе ехсhangе and sеlесtionagainst hyЬrids. onе of thе Ьеst-doсumеntеdехirmplеsof rеinforсеmеntoссurs in thе Ьеnthiс and limnеtiс есOtYpеsfound in lakе populations of thе thгееspinеstiсklе_ b a с k . H o w а r d R u n d l е a n d D o l p h S с h l u t е r ( 1 9 9 8 ) d е m o n s t r а t е dЬ o t h i n laЬoratoryсrossеs аnd in F1 lrr.bridsdеtесtеd in wild populations that hyЬrids suffеr a foraging disadvаntagеrеlativе to thеir parеntal spесiеs in thе parеntalеnvirсlnmеnts.In thе laЬoratory F1 hybrids rеarеd in a сommon еnviгonmеntwith ar-rrplе aссеssto food showеd growth ratеs similar to thosе of paгеntalspесiеs.Howеvеr, in fiеld studiеs F1 h,vЬгidsrеarеd in еitlrегtypе of parеntalеnvirсlnmеnt,littoral :rnd limnеtiс zonеs of lakеs' had lowеr growth ratеsand wеrе smаller at maturity than еithеr purе parеntal spесies.HyЬrids Wеrеpoorеr at сatсhing Ьеnthiс invеrtеЬratеsand plankton in thе diffеrеnt fiеld еnvironmепtsЬесausеof intегmеdiatеgill-rakеr numЬеr and Ьody sizе. In аdditiсln, Ьеrrtlriсfеmаlеs from svmpatriс poptrlаtions wеrе rrruсh lеss likеly to mаtе rvith intеrmеdi:rtе-sizеd F1 hyЬrid mаlеs than rvеrе Ьеnthiс fеmalеs from allopatriс populatiсlns whеrе limnеtiсs did not oссur. Thеsе rеsultssupport a modеl of rеinforсеmеntof sizе-assortativеmating prеfеrеnсеs through natural sеlесtiсlnagainst intеrп-rеdiatе-sizеd hyЬrids that havе lower fitnеssin еithеr pаrеntаl environmеnt. How irrrpoгtanthas rеinf
196

The Pаttern аnd Prrlс.,еssсlf SDeсiаtiсlп

sЕxUAL sЕLEст|oN AND ЕсoLoG|сAL sPЕсlAт|oN Sеxual sеlесtion' a forсе that aсts on traits that inсrеasеmаting suссеss'сan Ье influеnсеd Ьy thе еnvironmеnt and' as suсh' miry сontriЬutе to есologiсal spесiation.Sеxuаl sеlесtionthat lеads to spесiаtionirs a rеsult of divеrgеntsеlесtion Ьеtwееn еnvironmеnts сiln rеsuit fronr spаtial vагiation in sесondaгy sеxual traits, suсh as сlinal variation in malе plumagе or сoloration in rеsponsе to a vaгying еnvironmеntal gradiеnt. For ехamplе, сlinal variation in thе availaЬility of foods high in сarotеnoids that lеаd to Ьright rеd and orangе сoloration in malе Ьirds has Ьееn suggеstеdas thе primary сausе for divеrgеnсе in plumagе among populаtions in malе lrousе finсhеs, Саrpodасus mехiсапus (Hill 1994). A rr-roс{еl that dеmonstratеsthе importanсе of pаrailеl сlinal variation in fеmаlе mаting prеfеrеnсеsas a геsult of еnvironmеntal variation in malе signаling traits was first proposеd Ьy Russеll Landе (1982), Ьut good ехamplеs of сlinal variation that lеads to spесiation via sеxual sеlесtion arе laсking. Natural sеlесtion through variation in fеaturеsof thе еnviгonmеnt whеrе mating signals arе propagаtеdсаn геsult in divеrgеntsеxual sеlесtionof malе mating signаls' suсh as сourtship displays or nuptial сoloration' lеading to prеmating isolation Ьеtwееn populations from divеrgеnt signaling еnvironmеnts (Ryan and Rand 199З; Boughman 2ОО2).Natural sеlесtion сan also aсt upon thе sеnsory systеm of fеrтalеsas wеll, lеаding to sеnsory Ьiasеsfor сеrtain propеrtiеsof mаlе signals (е.g',brightеr сoloration, largеr sizе, loudеr and longеr durаtion of voсаlizations). Partiсular fеaturеs of lосal еnvironmеntal сonditions сould altеr sensory Ьias or mаkе somе malе traits Ьеttеrat ехploiting biasеs in сеrtain еnvironmеnts than in othеrs. In addition, fеmalе mating prеfеrеnсеs for malе traits that arе indiсators of supеrior quality сan also Ье influеnсеd Ьy thе signaling еnvironmеnt' For еxamplе, if partiсular mаlе traits arе morе rеliаЬlе indiсatoгs of quality in somе еnvironmеntsthan in othеrs (Sсhlutеrand Priсе I99З), divеrgеnсеirr prеfеrеnсеsbеtwееn еnvironmеnts for thеsеmalе traits сould lеad to prеmating rеproduсtive isolation Ьеtwееn thеm. Thus diffеrеnt сoеvolutionary paths of signals аnd prеfеrеnсеs in diffеrеnt еnvironmеnts сould Е]еnеratеspесiatiorl. Thе Ьеst еxamplеs of an importirnt rolе for sехual sеlесtionin prolnoting spесiation as а rеsult of varying signaling еnvironпrеIrtsсomе from spесiеs that livе in environmеnts that vary in light irrtеnsiryor transmission propеrtiеs that influеnсеthе spесtral quality of signals (i.е.'whiсh сolors irrе Ьеst rеflесtеd Ьy partiсular еnvironmеnts).For еxamplе, allopatriс populations of Aпolis cristаtеllцs lizards oссur in two diffеrеnt еnvironmеnts (хеriс and mеsiс) that diffеr with rеspесt to light intеnsity and thе spесtral quality of сolors thаt аrе Ьеst геflесtеd.Маnuеl Lеаl and Lеo Flеishman (2004) havе shown thаt malе anolеs frorrr thе two еnvironпrеnts diffеr in thе сolor and pattеrn of thеir dеwlaps (folds of skin undеr thе throat that arе distеndеdin malе displays usеd aS tеfritorial аnd mating signals)in thе dirесtion that inсrеasеssignаl dеtесtaЬilityin еaсh haЬitat. Мalеs fгom thе xеriс еnvironmеnt havе darkеr and slightly rеddеr dеwlaps that mахiпrizе сontrаst whеrе thе

Ьaсkgrсlund radianсе i ovеrall Ьrightnеss of tJ m е n t h i r v ее v t l l v е dЬ r i аnd tгallsmissiun аt а| hаЬitats'whеrе thе Ьa i n d е w l . r ps i g n a l sw l l u wirlr tlrеWrongdеw|.r and hеrrсеlеss likеly tс

тHЕ RoLЕ oF s NoNЕсoLoG|с

М o d е l s t r f s е х u a Is е | с mating prеfеrеnсеsfor u [ а r i o n sс а n d i v е г g еl l and spесiation. Supеrf s p е с i e t i с l l l .е х с е p t t h i t m а l е n l а t i n g ,s i g n l r l sr h p r o p е r г i е st o t h е s i g n l I p r o m < l г е dг h r t ' u g hd i v t onе modеl of fеma runаWaу proсеss (or .. F i s h е r i а n p Г o с е s s е sa r с tlrе tttсlstеxгrеmе rtr.tl p а r а J i s еo r t h е Ь г i g h r tion of thеsе traits аris that еnсodе thе attraсt foг that tгeit. FisЬеr.s a n d t h с г еi s а Ь u n d a n tt promoting thе еvolr.rti 1994); howеvеr, studiе сult to pinpoint. Onе span length in stalk-е Gеrald Wilkinson and wild fliеs' a slrort-еyеo Г s е l е с г i o n .t h е y f o L r n a I l y s е I е с t е dm a | е t r e i t from thе linе sеlесtеdf with short еyе spans' . prеfеrrес1malеs with lс е r е n с е s i o r е у е - s p a nl t s t a l k - е y е df l i е s t h e t d i Г S е x u а l s е l е с r i о nm l g е п е s \ .U n d е г t h i s m o d fеmalе lvith informatiсl mаkе mating dесision

Thе Раttеrп апd Prrlссssrlf S1lесiаtiсltt 1 9 7 oG|сAL sPЕс|Aт|oN ts that inсrеasеmating suссеss'сan suсh, mаy сontribr.rtеto есologiсal pесiationas a rеsult of divеrgеnt sеfrom spatial variation in sесondary m a | еp l u m a g еo r с o I o г а t i o n i n r е )nt.For ехаtrrplе,сlinal vaгiаtion in lids that lеad to Ьright rеd and orggеstеdаs thе primary сausе for diin malе housе finсhеs, Саrpodасus ionstratеsthе importanсе of parallеl еnсеs as a rеsult of еnvironmеntal proposеdby Russеll Landе (|982)' at lеads to spесiation via sеxual sеfеaturеsof thе еnvironmеnt whеrе in divегgеntsехual sеlесtionof malе ys or nuptial сoiorаtion, lеading to s from divеrgеntsignаling еnvirono 2002\. Natural sеlесtion сan also s wеll, lеading to sеnsory Ьiasеs for ightеrсoloration,largеr sizе, loudеr 'artiсillaг fеаturеs of loсal еnvirons or mаkе somе malе traits Ьеttеr at i than in othеrs.In addition, fеmalе ге indiсatorsof supеrior quality сan :onmеnt.For ехamplе' if partiсular f quality irr somе еnvironmеnts than rgеnсеin prеfеrеnсеsЬеtwееn еnvito prеmating rеproduсtivе isolation lary pathsof signalsand prеferеnсеs spесiation. I е f o r s е х t r a sl е l е с t i o ni n p r o m o t i n g tg еnvironmеntsсomе from spесiеs h t i n r е n s i r yo r t r a n s t n i s s i o np г o p е r ;ignals(i.е.,whiсh сolors arе bеst fееxamplе,allopatriс populations of diffеrеnt еnvironmеnts (хеriс and ntеnsityand thе spесtral quality of еal and Lеo Flеishman (2004) havе nvironmеnts diffеr in thе сolor and rdеr thе throat that arе distеndеd in ing signаls)in thе dirесtion that int . М а l е sf r о m t h е x е r i с е n v i r o n m е t r t ; thаt maхimizе сontrast whеrе thе

baсkgroundradianсе is rеlаtivеlу high (i.е.,thеy will appе?1гdarkеr than thе ovеrаllЬrightnеssof thе Ьaсkgrоund), whilе rтalеs from thе mеsiс еnvtrtlnmеnthavе еvolvеd Ьright dеwlaps Ьесausеof thеir rеlativеly higЬ геflесtanсе and transmissionаt all wavеlеrrgths.Suсh mаlеs arе morе dеtесtaЬlеin mеsiс hаЬitats,whеrе thе bасkgrounсl haЬitat light lеvеls arе low. Tlris divеrgеnсе in dеwlap signalswould minimizе gеnе fltlw ЬеtwееnhaЬitats, Ьесausеmalеs with thе Wrong dеwlaр сolor pattеrn would Ье lеss dеtесtаЬlеЬ,vсonspесifiсs and hеnсеlеss likеlу t() sесurеa tеггitory or oЬtаin nlаtings. тHЕ RoLЕ oF sЕxUAL sЕLEст|oN IN NoNЕсoLoG|сAL sPЕс|Aт|oN Modеls of sехu;rl sеlесtion, partiсtrlarly mtldеls of thе еvollttioll сlf fеmаlе matingprеfеrеnсеsf
198

Тhе Pаttеrп апd Proсеss of Spесiаtioп supеrior quality to hеr offspring. Although this mесhanism may potеntially lеad to spесiation if thе indiсator traits diffеr Ьеtwееnpopulations, likе runaway sеlесtion,еmpiriсal еxamplеs arе rarе. Somе еvidеnсе indiсatеs that a good.gеnеs mесhanism may promotе diffеrеnсеs in mаlе gеnitalia that lеad to divеrgеnсе in somе insесt taхa, although this hypothеsis is still undеr dеЬаtе (Нoskеn and Stoсkleу 2004).It should Ье notеd that for Ьoth indiсatоr and Fishеrian traits' thе laсk of сonсlusivе еmpiriсal еvidеnсеdoеs not mеаn that divеrgеnсеis unlikеly to Ье a produсt of thеsе mесhanisms;rathеr, it is oftеn diffiсult to distinguish whiсh mесhanism may hаvе opеrаtеd in thе past. An additional rolе of sехual sеlесtionin spесiationсan Ье traсеd to undеrstanding thе mесhanisms assoсiatеd with sехual сonfliсt. Sехual сonfliсt arisеs whеn thе Ьеst stratеgy for сlnе sеx is diffеrеnt (or еvеn dеtrimеntal) сomparеd with thе Ьеst strаtеgy in thе othеr sех. This antagonism is prеdiсtеd to lеad to a сoеvolutionary arms raсе whеrе diffеring sеts of traits Ьеtwееn thе sехеs intеraсt to dеtеrminе thе naturе of malе-fеmalе intеraсtions (Arnqvist and Rowе 2005). An ехamplе of within-spесiеssехual сonfliсt is thе еffесts of sеminаl fluid in Drosopbilа melаnogаstеr. Sеminal fluid has Ьееn shown to Ье Ьеnеfiсial to malе fitnеss' rеduсing fеmalе rеmating and inсrеasing ovulation, Ьut it is toхiс to fеmalеs; thе morе sеminal fluid thеy rесеivе, thе fastеr thеy diе. Sехual сonfliсt appеarsto oссur aсross a widе rangе of taxa (Arnqvist and Rowе 2005), Ьut prеdiсtaЬly,somе of thе Ьеst еvidеnсе for a гo1еof sехual сonfliсt in spесiation сomеs from insесts (Arnqvist еt al. 2000). Bесausе sехual сonfliсt may lеad to rapid еvolutiоn in thе rеproduсtivе traсt, it follows that it may also inсrеasеthе paсе of rеproduсtivе isolation Ьеtwееnpopulations. sЕXUAL sЕLЕст|oN' lsoLAт|oN' AND RAтЕs oF sPЕсlAтloN Sехual sеlесtion,Ьесausеof its rolе Ьoth in promoting thе еvolution of prе. mating rеproduсtivе isolating Ьarriеrs and in сontinuеd divеrgеnсе Ьеtwееn spесiеs,may havе а сonsidеraЬ1еimpaсt on thе ratе of spесiation (rеviеwеd by Panhuis еt al. 2001). For еxamplе, taхa with a widе rangе of sеnsory pеrсеption сapaЬilitiеs may bе partiсularly pronе to spесiation through sеxual sеlесtion, sinсе thеy havе аn еlеvatеd aЬility to produсе or dеtесt a Ьroad rangе оf signals, Ье thеy visuаl' aсoustiс, or phеromonal (Andеrsson 1994). Spесiеs-riсh groups оf frogs' for instanсе, сan dеtесt a widеr rangе of advеrtisеmеnt-сall frеquеnсiеs than thosе in lеss spесiosе linеagеs, potеntially aссounting for why suсh linеagеs of frogs arе morе spесiosе сomparеd with thosе with narrowеr frеquеnсy pеrсеption rangеs (Ryan 1986). In addition, rеinforсеmеnt,as dеsсriЬеdеarliеr, сan сomplеtе thе spесiationproсеss upon sесondary сontaсt Ьy еnhanсing divеrgеnсе of fеmalе mating prеfеrеnсеs. Sеxual sеlесtionplays an important rolе in sympatriс spесiation as wеll. Assortativе matin8' thе propеnsity to matе with likе individuals, hаs Ьееn proposеd аs onе way to quiсkly еvolvе rеproduсtivе isolation (Ссlynе and orr 2004) and is a nесеssaryсomponеnt of thе sympatriс spесiation proсеss.

Sеxual sеlесtion has Ьt part Ьесausе of its dirес 2 0 0 1 ) . S p е с i е so f Ь i r d s r thought to еxpеriеnсе st monogamous linеagеs;tJ spесiosе (Mitra et a|. 199 r a t е si of high sPесiаtioI1

pаrisonsof diсhromаri with fеmalеs dull) сladеs usually Ьright) сladеs (l

amountS of fеаthеrornar havе Ьееn oЬsеrvеd in an and othеr invеrtеЬratеs е t a l . 2 0 0 1 ) . A r е с е n tе x rеsult оf sехual sеlесtio Lаupаlа. Tamrа Mеndеl spесiеs at molесular mar tivе agеs of thе diffеrеnt i n o n е с l а d е o f t h е s ес r i с spесiеs pеr million yеars сiation in this group app song trill ratе, whiсh fеп appеar to Ье any есolog сriсkеt spесiеs.Thеsе aг tion сan Ье an importаn Prеmating isolating baгr

тHЕ RoLЕ oF Ml

Mutаtional сhangеsass thought to Ье a primar rWhitе (7978, 336) сonсl thе primary rolе in thс widеsprеad rolе of kaгy сausе thе aссumulation t h t t u g h t t о h е l a r g , е l уi r problеm with thе viеw tion сеntеrs on thе diffiс lations rеасhing fiхatto аltеrnativе rеarrangеm Ьrids, thеrеЬy rеduсing mosomаl rеarrangеmе ехtrеmе сhromosomal r

in сhangеs in сlrromos сhromosсrmal rеarrang arе inеffесtivе Ьаrriеrs1

Tllе Раttеrn апd Process of Spесiаtioп gh this mесhanisnrmay potеntially .ffеrЬеtwееnpopulations, likе runrrе. Somе еvidеnсе indiсatеs that a fеrеnсеsin malе gеnitаlia that lеad gh this hypothеsisis still undеr dеrld Ье notеd that for Ьoth indiсator е еmpiriсalеvidеnсеdoеs not mеan ;t of thеsеmесhanisms:rathеr. it is nisrrrmay havе opеratеd in tlrе past. r spесiаtionсan Ье traсеd to undеrth sехr'rаlсonfliсt. Sехual сonfliсt к is diffеrеnt(or еvеn dеtrimеntLrl) o r h е r s е х . T h i s . r n t а g o n i s mi s p r е lсе wlrеrе diffеring sеts of traits Ье. n a t u r еo f m а l е - f е m а l еi n t е r a с t i o n s of within.spесiеssеxual сonfliсt is lа mеlапсlgаsler.Sеminal fluid has s, rеduсingfеmalе rеmating and inrlеs;thе morе sеminal fluid thеy rеp p е а r st o O с с u ra с r o s sa w i d е r a n g е 'еdiсtaЬly, somе of thе Ьеst еvidеnсе сoпrеsfrom insесts (Arnqvist еt al. to rapid еvolution in thе rеproduсеasеtI]еpaсе of rеpгoduсtivе isola-

Sехuаl sеlесtiorrhas Ьееn linkеd tсl rеlativеly higlr rаtеs of spесiation, in part Ьесausе of its dirесt еffесt on matе rесognition traits (Panlruis еt al. 200l). Spесiеs of Ьirds with highеr lеvеls of promisсuity, for ехamplе, arе thouglrt to ехpеriеnсе strongеr sехual sс.lесtionthan сlosеly rеlatеd, morе moпogamous linеagеs;thеsе promisсuolls linеagеs gеnеrally arе also morе spесiosе(Мitra et al'.1'996).othеr studiеs of Ьirds сoпform to thе prеdiсtion of high spесiation ratеs in taхa with strong sеxual sеlесtion,inсluding сomparisons of diсlrromatiс (sехеs of diffеrеnt сolors; nralеs gеnеrally Ьright, with fеmalеsdLrll)сladеs vеrsus monoсhromatiс (Ьotlr sехеs thе samе сolor' usually Ьright) сladеs (Bаrraсlough еt аl. 1995) and сladеs with vaгying amountsof fеаtЬеrornamеntation (Мollеr and Сuеrvo 1'998).Similar trеnds havе Ьееn oЬsеrr,еdin angiospеrnrs(аnd thеir assoсiatеdpollinatoгs),insесts аnd othеr invеrtеЬratеs,arrd fishеs (rеviеwеd in Andеrsson |9941 Pаnhuis е t a l . 2 0 0 1 ) . A r е с е n tе x a m p l е h i g h l i g h t i n gt h е r a p i d r a t е o f s p е с i a t i o na s а rеsrrltof sехual sеlесtion hаs bееn shown in Hawaiiаn сriсkеts in thе gеnus Lаupаlа. Tamra Jv{еndеlsonand Kеrry Shaw (200.5)usеd divеrgеnсеamong spесiеsat rnоlесularmarkеrs саliЬratеd with gеologiсаl еstimаtеsof thе rеlativе agеsof thе diffеrеnt Hawaiian islands to show thаt thе ratе of spесiation in onе сlаdе of thеsесriсkеts from а singlе islаnd was сalсulatеd at ovеr four spесiеspеr million yеars,thе highеst ratе еvеr сalсulаtеd for arthropods. Spесiatioп iп tlris group appеars t
{, тHE RoLЕ oF MUтAт|oN lN sPЕс|Aт|oN in promoting thе еvolution of prе_ rd in сontinuеd divеrgеnсе Ьеtwееn on thе ratе of spесiation (rеviеwed :a with a widе rangе of sеnsory Pеrpronе to spесiationthrough sехual lility to produсе or dеtесt a Ьгoad , or phеromonal (Andеrsson 1'994). nсе' сan dеtесt a widеr rаngе of in lеssspесiosеlinеagеs,potеntiаlly 's arе morе spесiosе сomparеd with ln rangеs(Ryan 1986). In addition, эmplеtеthе spесiationproсеss upon :nсе of fеmalе mating prеfеrеnсеs. in sympatriсspесiation as wеll. Aswith likе individuаls, has Ьееn pro:oduсtivеisolation (Сoynе and orr 1еsymPatгiсspесiation pfoсеss.

Мutаtional сlrerngеs assoсiatеdwith сhromosomal rеarrangеmеntswеrе onсе thought to Ье а primary nrесhanism of spесiation. For ехamplе, М. .}. D. whitе (1978, 336) сonсludеd that сhromсrsomalrеarrаngеmеntshаvе ..playеd thе pгimary rolе in thе majоritv of spесiatiсln еvеnts..'Мorе rесеntly thе ш,idеsprеad rolе of karyot,vpiссhangе in spесiatiorrlras Ьееn qtlеstionеd,Ье. саusеthе aссurnulation of сhromosomаl diffеrеnсеsЬеtwееn populations is thought to Ье largеly inсidеntal to spесiation (Sitеs and Мoritz 1987). The proЬlеm with tЬе viеw that сhromosomal rеarrangеmеntspromotе spесiatiсlnсеntеrson thе diffiсulty оf аltеrnzrtivеrеаrrangеmеntsin divеrging populаtionsrеaсhirrgfiхation. All modеls of сhromosomаl spесiation assumе that altеrnativеrеarrangеmеnts impair thе fеrtility or viaЬility of intеrspесifiс hyЬrids,thеrеЬуrеduсing gеnе flow and promoting fiхation of altеrnаtivесhro. mosomal rеаrrаngепlеrrts.Although tlris nrаy iikеh' Ье truе in ехапrples of ехtrеmесhroпrсlsomalrеаrratrgеmеnts(suсh as lтutational еvеnts that rеsult in сhangеsin сl.rromosomеnumЬеr)' а numbеr of studiеs havе shown that сhгomosomalrеarrangеmеntsOftеn hаvе littlе еffесt on fеrtility аnd hеnсе arе irrеffесtivеЬaггiеrstO gеl1еflow (Spiгito |998),

199

200 Tbe Pаttеrп апd Proсеss of Spесiаtioп Lorеn RiеsеЬеrg and сollеaguеs havе studiеd rесomЬinational spесiation in sunflowеrs (Heliапtbus spp.) and thе еffесts of сhromosomal rеarrangеmеnts in сontгiЬuting to thе spесiation proсеss.RесomЬinational spесiation oссurs whеn two diploid spесiеs intеrbrееd and givе risе to a nеw linеagе that is both fеrtilе and truе Ьrееding br.rt is rеproduсtivеly isolatеd from both parеntal spесiеs.RiеsеЬеrg (2001) arguеs that сhromosomal rеarrangеmеnts that arе hеtеrozygous in hyЬrids havе majоr еffесts on supprеssing rесomЬi. nation Ьеtwееn сhromosomеs that сaггy thе rеarrangеd sеgmеntsand gеnеs linkеd to thеsе sеgmеntson thе сhromosomеs. Gеnеs unlinkеd ro thе сhгomosomal rеarrangеmеnt sеgmеnts,еspесially those that arе nеutral' frееly introgrеss Ьеtwееn the hyЬridizing parеnt,al spесiеs. Rеarrangеmеnts that supprеss rесombination Ьut laсk a сausal еffесt on hyЬrid fitnеss сould aсt synеrgistiсally with linkеd isolation gеnеs to еxtеnd thеir еffесts ovеr a largеr gеnomiс rеgion. Thus сhromosomаl rеarrallgеmеntsproЬaЬly do play an im. portant rolе in rеduсing gеnе flow aсross spесiеs Ьаrriеrs, Ьut not Irесеssarily through thе mесhanisms of rеduсеd hybrid fitnеss traditionally еnvisionеd. Thе hyЬrid sunflower spесiеs H' апomаlus, whiсh rеsults from hyЬridization Ьеtwееn H. аппuцs and I.I' petiolаris, is thought to havе arisеn in suсh а mannеr. In аddition, H. апomаlus has highеr fitnеss in novеl еnvironmеnts whеrе Ьoth of its parеntal spесiеs pгogеnitors do poorly. Suсh аn adaptivе rolе for hyЬridization in fostеring spесiation has bееn suggеstеdfor a numЬеr of plant and somе animal spесiеs (Arnold 19971Dow|tng and Secot 1997). sPЕсlAтloN

вY PoLYPLolDY

Polyploidization oссurs through thе dupliсation of еntirе sеts of сhromosomеs and is onе of thе fеw mесhanismsthat сan produсе instantanеousspесiation (polyploid spесiеsarе rеproduсtivеly inсompatiЬlе with thеir diploid progеnitors). Polyploid spесiеs arе formеd еithеr tЬrough gеnomе dupliсation of a singlе diploid spесiеs(autopolyploidy)or through thе fusion of two or morе diploid gеnomеs as a rеsult of intеrspесifiс hyЬridization (allopolyploidy). Both mесhanisms of pоlyploidy arе сommon in fеrns' mossеs,algaе, and virtually all groups of vasсulaг plants, partiсularly angiospеrms (StеЬЬins 1950;Lеvin 2002). How polyploid spесiеsЬесonrееstаЬlishеdis not fully undеrstood.Sеvеral сonditions, partiсulaгly сommon in plants, might еnaЬlе a nеw polyploid to inсrеasе and form a viaЬlе population. Thеsе inсludе sеlf.fеrtilization' vеgе. tativе propagation' highеr fitnеss than thе diploid progеnitor spесiеs, or niсhе sеparation from thе diploid progеnitor spесiеs'Indееd,many polyploid taxа rеproduсе Ьy sеlfing or vеgеtultivеpropagation, аnd most diffеr from thеir diploid progеnitors in haЬitat and distriЬution. lnсrеasеsin ploidy altеr сell sizе, watеr сontеnt ratе' ratе of dеvеlopmеnt, and many othеr physiologiсal propеrtiеs' so many polyploids may havе sеlесtivеadvantagеSin nеw есologiсаl niсhеs imnrеdiatеlyupon thеir origin. An цnusual сasе of polyploid spесiation in animals oссurs in thе gгay rrее frog spесiеsсomplеx found throughout thе еastеrn Unitеd Statеs.Thе сomplеx

сontаirrs а diploid spе spесiеs Hуlа uersiсolor lopiltгy (H. сhrуsosсelis northегl.l lralf), Ьut thеy tlrеir rarrgеsovеrlap. Di1 produсtivеly isolаtеd frt nаl diffеrеnсеs) and pс intеrЬrееding. Мalеs pl ratеs, with thе diрlkt.Us mitoсhondrial gеnе rеgr this study showеd thirt а г r i Ь u г е dt o m t r l r i p l еo r i g , 8). Two of thе thrее dip suggеstеd Ьy thе oссurrе not in thе iiving diplс t е t r а р l l l i d sa r o \ е t h r ( ) u diffеrеnt diplсlid аnсеsto аrсlsе from diffеrеnt dip sympаtry. Bесаusеthе dl latеd from onе antlthеr,, u с r s iс tl l t , r . P о l у p l t ' i di z . r t sisсеntсharrgеin thе аdv сеll sizе, whiсh hаs Ьееn сially prodцсеd аutotrip сhаngеs in trill ratе аs a r til.ltlitу Ьеtwееn lirrеаgеs rеinftlrсеd tri Il-reltеdiffеl grаy trее frogs illustratе aгisе аnd furthег shows mеnt саlls, сan Ье сlirесt

тHЕ RoLЕ oF GЕ

Irr thеory, gеnеriс drift outward from thе еdgе whеn a small nulrlЬеr tl] а nеw popr-rizrtiсlr-r. Irrpr: foгmatiсrn сrf rrеw spесt

Thе Pаttеrп аnd Procеss of Spесiаtion rdiеdrесomЬinationalspесiation in ts of сhronrosomаl rеarrangеmеnts R е с o m Ь i n а t i o n аslp е с i a r i o no с с u r s givе risе to a nеW linеagе that is еproduсtivеly isolatеd frоm Ьoth that сhromosomal rеarrangеmеnts jor еffесtson supprеssing rесomЬithе rеarrarrgеdsеgmеnts аnd gеnеs omеs.Gеnеs unlinkеd to thе сhгorlly thosеthat arе nеutral, frееly in. Ltal spесiеs. Rеarrangеmеnts that l еffесt on hyЬrid fitnеss сould aсt to еxtеnd thеir еffесts ovеr а largеr angеmеntsproЬaЬly do play an imspесiеsЬarriеrs'Ьut not nесеssariIy rid fitnеsstraditionally еrrvisionеd. s, whiсh rеsultsfrom hyЬridization thought to havе arisеn in suсh a i g h е rf i t n е s si n n o v е l е n v i r o n m е n t s ritors do poorly. Sцсh an аdaptivе on has Ьееnsuggеstеdfor а numЬеr 1 9 9 7 ;D o w l i n g a n d S е с o r t 9 9 7 ) '

lliсation of еntirе sеts of сhromo. hat сan pгoduсеinstantanеousspееly inсonrpariЬlеwith thеir diploid эd еithег through gеnomе dupliсa,loidy)oг thrоugh thе fusion of two rtеrspесifiсhyЬridization (аllopolytrесommon in fеrns, mossеs, algaе, .ts,partiсularly angiоspеrms (Stеbhеd is not fully undеrstood. Sеvеral s, might еnаblе a nеw polyploid to h е s еi n с l u d еs е l f - f е r t i l i z a t i o nv,е g е . t h е d i p l o i d p r o g е n i t o r s p е с i е s ,o r toг spесiеs.Indееd,many polyploid propаgation' and most diffег from istribution'Inсrеasеsin ploidy altеr )pmеnt'and many othеr physiolog'havе sеlесtivеadvantаgеs in nеw origin. n in animals oссurs in thе gray trее ) еastеrnUnitеd Statеs.Thе сomplех

сontains a diplкliсl spесiеs, Hуlа сhrу51lsсеlis(2N=24) and a tеtraplоid spесiеsНуlа uеrsicolor (4N=48). Both spесiеs oссupy laгgе rеgions of al. l o p a t r y( I J . с h r l s o s с e l i s i n t h е s o u t h е r n h a l fo f t h е r a n g е ,H . u e r s i с o l o r i r r t h е northеrn half), Ьut thеy also ехist irr Sympatry in multiplе loсalitiеs whеrе thеir rаngеs ovеrlap. Diploids and tеtraploids rеproduсе sехually and arе rеproduсtivеlyisoIatеdfrom сlnе anothеr through Ьoth prеmating (mаting signal diffеrеnсеs)аnd postmating (tгiploid hyЬrids arе stеrilе) Ьarriеrs to intеrЬrееding.Malеs produсе advегtisеrтеntсalls thаt diffеr in thеir trill ratеs,rvith thе сliploid H. cЬr\,sсlsсеlЬаlrvays produсing сillls with fastеr trill ratеsthan tlrоsе of the tеtraploid H. uеrsiссllсlr(Gеrh:rrdt2005). Studiеs Ьy Сarl Gеrhardt аnd сollеaguеshavе shown that fеmalеs of Ьoth diploids and tеtraploids arе highly sеlесtivе (еsресially in sympatriс populations) whеn еvaluatingсall сharaсtеristiсsof malе advеrtisеmеntсalls, strongly disсriminatingagainst саlls with thе trill rate of thе ..wrong'' spесiеs. A rесеntstudy Ь,vAliсia Hollowаy аnd сollеаguеs(Hollowау еt al. 2006) has dеmonstratес] аn unusuаl pattеrn of p
201

202

t: tЕ

The Pаttеrп апd Process of Spесiаtion

Е Е

H, avivoсa

Еxtinоt |iyla sp.А (2N)NЕ

Figurе 8. A modеl of tеtraploidoriginsfrom diploid anсеstorsillustratеsmultiplе allopolyploid origins for thе gray trее frog Hуlа uersiсolor.Thе rеlationshipsof diploid gray trее frogs аnd a rеlаtеd spесiеs,H. аuiuoса,arе dеpiсtеdat thе Ьotto- of thе trее. Ехtinсt diploids (2N), l-/. sp. A and H. sp. B, wеrе infеrrеd from tеtraploid аllеlе linеagеs.Tеtraploid gray tгее frogs, H. uersiсolor (4N), wеrе formеd multiplеtimеs from еxtinсtdiploid anсеstors(AxB, AхС' and B x С). Tеtrаploid gray trее frogs from diffеrеntlinеagеs(е.g.,NЕ, NW) arе intеrfеrtilеand thus form a singlе Ьiologiсal spесiеsthаt sharеsa divеrsеgеnе pool of multiplеanсеstrаlprogеnitorspесiеs.(From Holloway еt аl. 2006.)

Ьy gеnеtiс drift. Thе idеa of fouпder-effeсt spесiаtioп (Figurе 4) was hrst proposеo o'y йnsт йЬyr 1i-У}.+i,Ьt6..;retrnеu'pz?rijъtri "if.tсittiлt1\.ltl "r';ъ. Ьasеd on his oЬsеrvation that in manу Ьirds and mammals, populations pеriphеral to thе distribution of a proЬablе..parеnt'' spесiеswеrе oftеn highly divеrgеnt,to thе point of Ьеing сlassifiеdas diffеrеnt spесiеs.Maуr proposеd that gеnеtiс сhangе would Ье vеry rapid in suсh loсalizеd founding populations

Ьесausе of random fiхat of anсеstral сoadaptеd 1 would lеad tо thе potеrsеts of gеnеs in thе nеr сould inсidеntally yiеld for rapid spесiation. Al p г o Ь а Ь | уd t l o с с u r i n f t t jor gеnе rеorganization son (1975) and Alan Tе onе potеntial еxamp drift, howеvеr, сomеs f: tion of shеlls) Ьеtwееn gеnus Еuhаdrа' TЬese :

Ь е t w е е nt h е m . С h i r а l i г with dехtral (right-han handеd) сoiling. Bесau (thеsе snails аrе hеrma f i х е d f o r o p p o s i r ес o i l i n lаtеd from onе anothеr positе сoiling typеs arе l gеnеtiс drift is likеly tс typеs аm()ng pllpulаtr drift is thе most plaus сhirаlity (vаn BatеrrЬu of at lеast four indеpеn through phylogеnеtiс (Uеshima and Asami 2

Consеquеnсеsof s

Thе Ьulk of this еssayh mесhanisms Ьy whiсh t sultеd in thе еnormous unсovеrеd in thе foss сhallеnging;hеnсеmot plеs. Although mrrсh d as illustratеd Ьy thе fс

onе spесiеs into anotht vеrsifiсation and spесt ologists gеnеrally agrе ditzеrgеnсеtоdav amo s p o n s i Ь l еf o г s p е с i e t i Thе tеmpo of spес groups' suсh as horsс for ovеr 1.50 million

.l'hе

Еxtinоt yla sp.A 2N)NЕ

diploidаnсеstorsillustratеsmLrltiplе |уlаuеrsiсolor.Thе rеlationshipsof H. аuiuoса,arе dеpiсtеdat thе ' sp.A and H. sp. B' wеrе infеrrеd ay trееfrсlgs,H. uersiсolor (4N), loid arrсеstors(A x B, A x С, arrd еntlinеаgеs(е.g.,NЕ, NW) arе spесiеsthat sharеsa divеrsеgеnе . (FromHollowаy еt al. 2006.)

' spеciаtion(Figurе4) was first рroed pеripаtriс spесiаtioп) and was rds and mаmmals, populations pе..parеnt'' spесiеs wеrе oftеn highly rs diffегеntspесiеs.N4ayr proposеd populations suсhloсаlizеdfoundir-rg

Pаttеrп апr] Prсlсеsso|.Spесiаtiсltt 20.з

bесausеof rarrс]omfixаtitrrr
Соnsеquеnсеsof Spесiation Thе Ьulk of this еssayhas foсr"rsеd on ехamplеsof living spесiеsand thе veгioLts mесlranismsЬy lvlriсh thеу arе thought tсl lravе spесiаtес.l. Yеt spесiatifspесiаtion аs illustratеd Ьy thе fossil rесord (phуlеriс gгаduirlisnl, tlrе slсlrv trаr-rsitiorr of onе spесiеsinto anothеr' vеrsuspunсtuatеdеqr'riliЬriurrr' rapid еvolutionarydivеrsifiсationand spесiationfollowеd Ьy long pеriods of stasis),еvolutionar,vЬiologistsgеnеrallvagrее that thе samе еvolr'rtionaryпlесhanismsthat proпrotе divеrgеr-rсe todа1,аnrong populаtitlnsof living spесiеs(nriсroеvt>lutiolr) аrе rе_ sponsiЬlеfсlr sресiationеvеnts(mасroеvtllution),Ьotlr сlngoingar-rdin thе past. Thе tеmpo of spесiation vaгiеs dramiltiсally among diffеrеnt taхa. Somе groups'suсh as hоrsеshoесraЬs (gеnus l-imulus), havе rеmаinеd unсhangсd for ovеr l 50 million vеars, w,hilе othеrs' sr'lсЬаs Hаr'r.аiianсriсkеts (gеnus

TЬe Pаttеrn апd Proсеss of Spесiаtioп Lаupаlа), havе spесiatеd rapidly, with up to 4.17 spесiеs pеr million yеars (Меndеlson and Shaw 2005). Thus spесiation сan oссur quiсkly or slowly, undеr а variеty of есologiсаl сonditions, and with or without thе еvolution of rеproсiuсtivе isolation. Unravеling thе mystеriеs of how nеw spесiеs arisе is onе of thе nrost еxсiting аrеas of еvolutionarу Ьiology' and although wе havе madе muсh progrеss in undеrstanding spесiation sinсе William Batеson's еarly сonсеrns, futurе studiеs promisе to yiеld еvеn morе nеw and fasсinating disсovеriеs. Thе hopе of thе futurе, in prеsеrving and protесting our plaпеt's Ьiodivеrsity, liеs in an r.rndеrstanding of thе proсеss of speсiation and а сommitmеnt

to saving thе produсts of this proсеss: thе spесiеs that ехist on еаrth today and thosе that hаvе yеt to еvoivе in thе ftrtr-rrе.

вlBL|oGRAPHY Andеrsson' IvI. 7994. Sехuаl Sеlесtioп. Prinсеton, NJ: Pгinсеton Univеrsity Рrеss. Arnold, М. L. 1997. Nаturаl Hуbridizаtiсlп апd Еuolиtiсlп. Nеw York: Oхford Univеrsity Prеss. Arnqvist, G., М. Еdvardssоn,LI. FriЬеrg, аnd T. Nilsson. 2000. Sеxual сonfliсt promotеs sресiation in insесts. Prосееdiпgs of thе NtttiсlttаlАcаdеmу сlf Sсiепсеs USА 97: 10460-10464. Arr-rqvist,G., and С. Rowе' 2005. SехнаI Сoпfliсt. Pгinсеtоn,NJ: Pril-rсеton Univеrsity Prеss. Bаrrасlough, Т. G.' P. H. Haгvеy, аnd S. Nее. 1995. Sехual sеlесtionand tахonotntс divеrsity in passеrinе Ьirds. Proсееdiпgs of thе Rol,аl Stlсiеtу of Loпdсlп, Sеriеs B 259: 211-215. Bаtеson,'w.1922. Еvolutionary faith and modеrn douЬts. Sсiепcе55: 5.5_61. Blair' W. F. 1955. Мating сall аnd stagе сlf spесiаtion in tllе Мiсrobуlа сlliuасеа_ М. саroliпепsls сomplех. Еuolиtkln 9: 469480. Boughman, J. .iи. 2002. How sеnsоry drivе сan promotе s1-lесiirtion. 7,rепdsiп Есоlogу апd Еuoluti
Г)iаz, A., and M. R. Масnаrr' p r е z r . g tilсt r е p r o d u с r i v еi p г . l g е r l i t o rМ . g u t t а t u s .i DoЬzhаnsk,v,T, 1937. Gепеt LIr-rivегsitуPrеss. l 946. (ioп.rplеtегt'pr spесiеs сlf Drostphilа. Е Dowlir'rg,Т. Е., апd С. l,. Sес in thе divеrsifiс:rtiol.ttlf : 28 59З_61'9. F е d е г , . | .L , | 9 9 8 . T h е a p p l el сOnvеntionalwisdom aЬ еds., Еlld/ess Fсlrnts:Sрс Urrivеrsit,vPrеss. Fishеr,R. A. l930. Thс С,еt Prеss' F u t r t v п t а ,D . J . , J . S . W а l s h T G с n е t i с v l r i l r t r с l litr l l t p l Ьееtlеs(Cоlеoptеrа:СJh F l ч ' l u Ii , l п а D , B i , ' l ' ' д 1 ' : Gеrhаrdt, Н. С. 2005. Aсlvе (H1'lа сhrуsсlsссlis tэ,ndL еvolution of сoпrmutrtс G г a n t , P . B . ' B . R . G r а n t , . | .J Darwin's finсhсs: p
Tlэе Pаttеrп апd Рroсеss of Spесiаtioп

p to 4.17 sPесiеspег million yеars latlon сan oссur quiсkly or slowly' 'nd with or Without thе еvolution of ) е с i е sa г i s еi s о n е o f t h е m o s t е х с i t lough wе havе madе muсh progrеss m Batеson'sеarly сonсеrns' futurе rd fasсinatingdisсovеriеs. Tlrе lropе ] our Planеt'sЬiodivеrsity,liеs in an )n аnd a сommitmеnt to saving thе ехist on еarth today and thosе that

гon, N-J:Prinсеtоtl Univеrsity Рrеss. пd Еuolutioп. Nеw Yоrk: Oхford r. Niissorr' 2000. Sехuаl сorrfliсt 4sof thе Nаtioпаl Асаdеmу of Sсieпсеs NJ: Prinсеton flсr. PrinсеtoI-r, 1995. Sехuаl sеlесtiorrand taxсlnomiс f the Rowl Soсietу rlf Lспсloп, Sеriеs dеrn doubts.Sсiеnсе.55:5.5_61. есiation in tЬе Мicroh1'lа oliuасеа9-.180. n promotе spесiаtion.Тrепds iп |tlvеpfеssurеs'vаriaЬility' irnd sехu:rl ;епsсhаfteп72: 204-2О6. пd Еuolutioп of thе Gепus Rhagolеtis Саmbridgе, lvIA: Mrrsеum оf and spесiationin trugivorousfliеs of e). Еuolutioп 2З: 2З7_251,. l at thе diploid Ieуе|,Аmеrrcап Sundеrland,МА: Sinаuеr Assoсiatеs. :ion analysis. Сurrепt Оrnithologу е еmpiriсаlсonsеquеnсеsof altеrnаtivе rs аnd proсеssеsot diffеrеrrtiation.In t аnd lts Сoпsеquепсes,28-59, lndоn: Jolrn lV{urrаy. zski.and R. Е. SilЬеrglied.1997. lxrеnding H:rldаnе's ru|e. I'rсlсееdiпgs 164:845-8-51.

Diаz, A., and N'I.R. Масruil:. 1999. Pollеn trrЬесoпrpеtitionаs a mесhanism of рrеZygotiс rеpгoduсtivе isolаtiоn Ьеtwееn Мilтшlus п[rsl|tusand its prеsumеd рrogеnitor М. gLtttаtus.Nсlu Phуtсllogist 144: 47 \478. Dobzhansk1.,T . 19з7 . G епеtiсsапd tbе Оrigiп of Spесlс's.Nеw York: СolumЬia Univеrsitr'l,rе's. 1946. Сoпlplеtе rерrodLrсtivеisolаtiorrЬеtwееntll,o rтorphologiсal11. similar spесiеsof Dкlsophilа. Есoklgу 27:2()5_211. Dowling, T. Е., and С. L. Sесor. 1997. Tb,erolс of hyЬridization and introgrеssion in thе divеrsifiсation()faniпlаls. Аппцаl Rсuieн' of ЕссlIogl'апd Sуstеmаtrcs 2 8 : 5 9 3 - 6 19 . Fеdеr,J. t-. 1998. Thе,rpplе lnаggot flу,Rhаgсllеtisponюпеlld fliеs in thе tЪсеof сonvеntiollаl .uvisdomаЬout spесiatiоп?In D. J. Howard and S. H. Bеrloсlrеr, еds., Еиdlсss l:orms: Spесiеs апd Spес:iаtitlп,1.3О_|44. Oхford: oxford Urrivеrsit1, Prеss. Fishеr,R. A. 1930. Тhc Gепetiсаl Тbеltу of Nаtиrаl Sеl,есtiс>п. oxford: Сlarеndon Рrеss. .Walsh.)г., F u t u } . l l l аD' . J . , J . S . T . M o r t r l n , D . . I . F . u n k ,a n d М . С ' K е е s е .1 9 9 4 . Gеrrеtiсvirriation in а рhуlogеnеtiссontсхt: Rеsponsеsof two spесializеdlеaf bееtlсs(Ссllесlptеrа: Сlrrysсlmеlidас)tgs.Pпlсaеdiltgs tlf thc Rol,аl SftЬe Мoпtаstrаесt аппulаris ссlпiplех.Маriпе Biollэgу |27: 705-7|1. Lаndе,R. 19ti2. Rаpid origin I Аltсllislizards. Amеriсап Nаtиrаlist 16З 26_З9. Lеl.in, D. A. 2002. Тhе Rolе of Сhrtlmtls
205

206

Тhе Pаttеrп аttd Proсеss сlf Spесiаtioп Мayr, Е. 1942. Sуstеmаtiсs апd the Оrigiтt of Spссiеs.Nеw York: СolurтЬra Univеrsity Prеss. 19.5.1. Сlrarrgеot gеnеtiс еnr,ironшеnгalld еvolution. IrrJ. Huхlеv, A. С. Hаrdy, аnd Е. B. Ftrrd, еds.' Еuсllutiсlпаs а Pкlсеss' 157-1B0. [-ondоn: G е o r g с A l | е l l. l l l d I j n w i n . 1'96З.Апilпаl S1lесiеs апd Еt'olutiсlп.СarnЬridgе,МA: Bеlknаp Pгеssof Нaгvаrd Unir,еrsiгуPrеss. МсКinnon' J. s.' s. Мсlri, B. K. Blасkn.ran,L. Dаvid, D. М. Кingslе1',L..|anriеs.ln, rolе in spесii]tion. J' С1rou,arrd D. Sсhlutсr' 2004' Еvidеnсе ftlг ессllt>gу's Nаtttrе 429 294_298. Меad, L. S., аnd S. J. Aгnold. 2t)04. Quаntitаti\,еgеnеtiсrтосlеls
Sitеs' J. W.' J.., and С. Nlоrl rеvisitеd. Sу stеmаtiс ZtSokal, R. R., and Т. J. Сrov, еvaluation. Alпеriсап Ь Sorепson, J' D., K. М. Sеfс, brood pа rаsitiс indigс'b S p i r i t t - lр. . 1 9 9 8 .T h е г t l l ео f D. J. Howard аnd S. H'

32o-3z9.Oxford:Oхf.

StеЬЬins, G. L. 195О. Уаriаt Ul-rivегsitуPrеss. Sturtеvant' A. H. 1920. Gеr HyЬrids wtth Drosophl Tеmplеton, A. R. 1980. Tht

94 1О|1-1038. l989. Тhе mеaning а n d J . A . Е n d l е r ,е d s . , М A : S i n а u е rA s s o с i а t е Тing, С.-T.' S. С. Tsaur, М. homеoЬox at thе sitе O U е s h i r n a ,R . . а n d Т . A ч a m i . Nаturе 425 679. van BatеnЬurg, F. H. D., аn сoiling: Сomputеr ехpt van valеn' L. 1976, Есologi Whitе, М.J.D' 1978'Мod'

Сompany. -l Wilеy, Е. o. 978. Thе еvo Zoologу 27:17-26. .Wilkirrson, G. S., аnd P. R. sеlесгion on irn ехадgе Roуаl Soсiеtу' of Loпdt

Тhе Раttепt апd Prс.>cеss с;f Spесiаtiotl f Spесiеs'Nеrv Yoгk: СolumЬiа t and еvolution.IrrJ. L{uхlеv, t|o|1|lsа Proсеss,1.57-180' I,otrdоn: Саmbridgе,МA: Bсlknаp Prеss of David, D. М. Kingsiе1',[,..|an-riс'son, -.Iсlгесоlttgr..' г.llс ilt sресiltitllt.

ltivе gеnеtiстllodеlsof sехuаl sе|есtion. 4-27 1. spесiatiorrin аn arthropod. Nаturе )6' SPесlеsriсhлеssсovагiеswitЬ l4--s.51. ion and fеаthеroгnаrmеntationin Ьirds. ttttrаIsеIесtionin Druьrphilа. Nаtиrе 3quеnсеsof sr,rnpаtry.Herеditу ;pесiation:Tlrе еvolutior.rof lryЬrid il3. gеnеtiсsоf sрlесiаtitln. Gепсtiсs 744: Trсsсnzа.200l. Sехual sеlесtiorrand tioп 16:364-з71. lсеptof spесiеs.In Е. S. VrЬa, еd., l Мusеurn Mсlnograph no. 4. Prеtoria, Itrllt,gyltntJrrtс1|sig11.11 5tгl'lсгI-lге in .|oсusаntagoтlistiс сoеvсllutiсll.t, аnd thе ' J. Ноwаrd .rndS. Н. BеrlосIrег,еds., 61-270. Nеr,vYсlrk: Oхford Univеrsity lсlrv ехpсrimеnts сln sр.lесi:lгiсln: WIr:rг 7:1637-1653. gеmеntsand spесiatioll.Тrепds iп rсеmеntof stiсklеЬaсkmatе Еtlrllutioп 52: 200_208. ipесiаrionГatеsаmon8 l1пurаns. S с i c п с е sU S А 8 З : \ з 7 9 _ | з 8 2 . сognitionаnсlsеxual sеlесtlоnаs a 'n.L.uolution17: 647-657. sресiationЬ1'natural sеlесtton. сеption'and рoрulаtiсlndivеrgеllсеin е Rоуаl Sllсit'tусlf I'сlttdоп, Sеriеs lJ |хo||orтIJ'. Nеrv York: СolLtmЬia

.!7., Sitеs'J. Jr., anс.lC. Мoritz. 1987. Сhromosomаl еvсllutiоnаnd spесiation rеvisitеd.SуsttlпtаticZoolсlgу 36: 1 53-|7 4. Sоkаl, R. R., and T. J. Сrоvеllo. |970. Тhе Biоlogiсal SpесiеsСonсеpt: A сritiсal еvaluаtion.Атпеriсаn N аturаlist,l04: |27 -7 5 З. Sоrеnsсln' J. D., K. lt{. Sеfс, аnd R. B. Paynе. 2003. Spесiation Ьy host switсh in Ьrood parasitiс indigobirds. Nаturе 424: 928_93|. Spirito,F. 1998. Thе rolе of сhrоmosomal rеarrangеmеntsin spесiation.In D. J. Howard аnd S. Н. Bеrloсhег, еds., Еlldless Forms: Spесiеs апd Spесiаtiсtп, 320_з29. Oхford: Oхford UrrivеrsityPrеss. Stеbbins,G. l,. 19.50. Vаriаtioп апd Еuolиtiott iп PIапts. Nеw York: СolumЬia Univеrsity Prеss. stuгtеvant'^. L1. 192О. Gеnеtiс strrdiеson Dпlsсlphilа sinlulаns.I. Introdrrсtion. HyЬrids with Drosophilа mеIапсlgаstеr, Gепеtiсs.5:488-500. Tеmplеton,A. R. 1980. Thе thеory оf spесiationvia thе fоundеr prinсiplе. Gепеtiсs 9 4 : 7 О 1l,l _ 1 0 3 8 ' 1989. Thе mеaningof spесiеsаnd spесiatiоn:A gеnеtiсprrsресtivе.In D. Ottе and.|. A. Еrrdlеr, еds.' Spссiаtit,папd lts Сoпsеquеnсеs,2_27. Sundеrland, MА: Sinauеr Assoсiatеs. -l998. Тing, С.-T., S. С. Tsaur, М.-L. Iй/u,аnd С.-I. Yu' A rapidly еvolvirrg homеoЬoх аt thе sitе of а hyЬrid stеrility genе.Sсiепсе282: 150i_1504. Uеshima,R.' and T. Asami. 2003. Singlе-gеnеspесiationЬy lеft-rightrеvеrsal. Nаtt'trе 425: 679. van Bаtеnburg'F. H. D.' and Е. GittсnЬеrgеr. 1996. Еase of fiхation of a сha ngе in сoiliпg: Сomputеr ехpегimеntsoп сhirality in snаils' Hеrеditу 76:278-286. vаn Vаlеn, L. 1976. Есoiogiсal spесiеs,multispесiеs,and оаks. Tахoп ) 5:2зз-2з9. .W. Whitе, М. .J.D. 1978. Мodcs of Spесiаtio|1.Sаn F-ranсisсo: H. Frееmаn and Сompany. !Иilеy,Е. o.1978. Тlrе еvоlutiсlnаrvspесiеsс()nсеptгесorrsidеrеd'Sуstеmаtiс Zoolсlgу 27: 17-26. \{/ilkinson'G. S., and P. R. Rеillo. 1994. Fеmalе сhoiсе rеsponsеto аItifiсial sеlесtion on an ехaggеrаrtеdmalе trait in а stalk-еуеd flу. Proсеediпgs of thе Rolа! 5u,i,'.r' of Loпdoп, Sеriеs B 255: l_6.

207

Еvolution and Dеvеlopmеnt GrеgorуA. Wrау

i I Y

/Ft genoryрe

Thе intеllесtual histсlriеs of dеvеlopпrеntaland еvolutiсlnaгy Ьiology havе frolrr thе ЬirtЬ of Ьiology as a distiIlсt sсiеntifiсdis. Ьееn intеrtlvinеd alr.l-rost с i p l i n е ( М a v r 1 9 8 2 ; R i с h a r d s 1 9 9 2 ) . . Г h е r е a s t l n sа r е n o t d i f f i с u ] tt t l 1 i n d . Both еv
Tеmporal Parallеls Rссapitulаtion has by ttlгl1sеrrlightеnеd,еntеrtailrеd,lrnd ехаspеratеdgеrrеr. а t i o n s с l f Ь i o l o g i s t s( d е B е е r 1 9 4 0 ; G < l u l d| 9 7 7 ; С Ь u r с h i l l 1 9 8 0 ) .T h е r е с o g . nition of parallеls Ьеtwееn еmЬrуologiсаl еvеt-ltsаlld rеlationships among spесiеs prсdatеd thе сonсеpt tlf lriologiсal еvtllutitln, at [еast in its modеrn sеtrsеof trаnsmtltation irеtwееnspесiеs.Indееd,thе rvords еuriutiсlп and dе. uеlopпtепtwеrе usсd intеrсhangеaЬlyto rеfеr tсl thе unfolding of Ьoth indi. arrd plrуlеtiссllangе until tЬе Lrеginningrlf thе tц.еntiеth vidual dеvеlopn-rеnt 208

bitэt

lntе

Figuге 1. Gеnotypе to p gеnеtiс information into Ьеhavior,and physiolog whеre thеy influеnсеsur' еvolutionarymесhanism suссеssivеgеnеration.A how proсеssesopегаtеа1 link in our knowlеdgе w

сеntury (Hall 1992; Ri proсеssеswеrе сonsidе Еarly desсriptions o{ сast in tеrms of thе sса emЬryos of morе сomp sеmЬlеd simplеr onеs tееnth-сеntury prеforп t h е s а m е p г o с е s s .D u r i tors notеd that сhiсkеn that сontain fеaturеs of for instanсе, thаt humа w i t h l i m Ь s а p p е a r i n gi

still. Karl Еrnst von Baеr' vations of divеrsе аnirг tion (Hall 1'992i RicЬal thе еmЬryos of vеrtеЬr rеpгеsеnt adults of oth lowеr spесiеs do not a sеnсе of fins in thе еmЬ Ьryos of distinсt group

Еuolutioп апd DeueloDmепt 209 ev0li"rtr0nary meсhаПisms

g

)еvеlopmеnt

t

i

genOtype ntal and еvoiutitlnary Ьiolсlgy havе lf Ьiology as a distinсt sсiеntifiс dishе rеasonsаrе not diffiсult to find. nporal proсеssеs,and еvеry individwithin, and rеflесts'a muсh dееpеr rllеl forms thе Ьasis for thе сonсеpt ,pmеntlitеrally rеplаys еvolutionary еst аnd most pеrsistеntlyсontrovеrrtal Ьiol
biосhemiсal interaсt|Ons

deve|орmеntal рrOсess8s

оrgantsmaI рnenolypё

Figurе 1. Gеnotypе to phеnotypе.Thе proсеssеsof dеvеlopmеnttransmutе genеtiсinformationinto organismalphеnotypе,whiсh inсludеsanatomy' Ьеhavior,and physiolоgy. Thеsе traits, in turn' intеraсt with thе еnvironment, whеrеthеy influеnсеsurvivоrship and rеproduсtion. Naturаl sеlесtionand othеr evolutionarymесhаnismsсhangе thе rеlativе frеquenсiеsof gеnotypеsin еaсh suссеssivеgеnеration.A сomplеtе undеrstandingof еvolution rеquirеs knowing how proсеssеsopеratеat еaсh сlf thеsеstеps.Until quitе rесеntly,thе wеakеst link in our knowlеdgе was dеvеlopmеnt.

20021. lg gеllotypе into phеnotypе providеs ing thе intеraсtionsЬеtwееn еvoluRatf and Kaufiтan 1983; Wilkins thе еvolutior-r of orgаnismal phеnot h е yw е r еs е P a r a t еГ r o с е s s е sа. r е i n ; s е so f d е v е l с l p m е n(tF i g u r е 1 ) . T h е to do with есoiogiсal сontехt and с r a t i n gа p а г t i с t r l l rp h е n с l t y p i сo u г of a group o{ rеlatеd spесiеsсan Ье Lraсtеristiсsas it is Ьy adult anatсlmy,

еntеrtainеd,аrrdеxaspеratеdgеrrеrJ 1 9 7 7 1 С h u r с h i l l1 9 8 0 ) .T h е r е с o g :al еvеnts аnd rеlаtionships among ;al еvolution,at lеast in its modеrn Indееd,thе words еuolutioп aлd dеl rеfеr to thе unfolding of Ьoth indiuntil thе Ьеglnningof thе twеntiеth

сеntury (|1a|| 1992 Riсhards 1992)..sИhat wе rесognizе today as distinсt proсеssеswеrе сonsidеrеd inехtriсaЬly intеrtwinеd. Еarly dеsсriptions of parallеls Ьеtwееn dеvеlopmеnt and еvolution wеrе сast in tеrms of the scаlа nаturа (сhain of Ьеing). Aristotlе rесognizеd that еmЬryosof morе сomplех сrеaturеspassеd through stagеsin whiсh thеy rеsеmЬlеd simplеr оnеs (Gould 1977|. For Сharlеs Bonnеt, an еarly-еightееnth-сеnturyprеformationist, еvolution and dеvеlopmеnt Wеrе litеrally thе samе proсеss. During thе latе 1700s and еarly 1800s sеvеral invеstigators notеd that сhiсkеn and human еmЬryos pass through a sеriеs of stagеs ..lowеr'' or ..infеrior'' animals. thаt сontain fеaturеs of Johann Mесkеl, notеd, for instanсе'that human еmЬryos сontain gill slits and a tail at еarly stagеs' with limЬs appеaring aftеrwards' and dеfinitivе mammalian fеаturеs latеr still. Karl Еrnst von Baеr' who madе ехtеnsivе and mеtiсulous firsthand oЬsеr. vations of divеrsе animal еmЬryos, ехpliсitly rеjесtеd thе idеa of rесapitulation (Hall 19921RiсЬards \992). Hе сitеd thе prеsеnсе of uniquе fеaturеs in thе еmЬryos of vеrtеЬratеs,suсh as thе yolk saс) as еvidеnсе that thеy did not rеprеsеntаdults of othеr spесiеs;сonvеrsеly,hе notеd that somе fеaturеs of lowеr spесiеsdo not appеar in thе еmЬryos of higher onеs, suсh as thе absеnсеof fins in thе еmЬryos of Ьirds (Baеr 1 82 8 ). Baеr also notеd that thе еmbryоsof distinсt groups of animals did not pass through stagеsrеprеsеnting

2 1 0 Еuоlutiсlп апd D еuelopm епt othеr Onеs:..TЬе еmЬryil tlf а vеrtеЬratеis at tЬе Ьеgirrrringalгеасlуa vеrtеЬratе'' (translationfrom Riсhards |992, 59). Dеspitе Baег's potеnt сritiсisnrs,support for thе nсrtiоn of rесapitulation pеrsistеd for anothеr сеntury. Rесapitr.rlationthеory rеасlrеd its zеnith in thе ..ontogеnyrесаrvгitingsof ЕгrrstHaесkеl (1866, l875), whosе sгatеmеntthat pitrrlatеsphylсlgеny'' (..diе ontogеniе wеitеr niсhts ist als еinе kurzе Rесapitufсlr rтany Ьiologists lation dеr Phylogеniе'';1866,2,7) еr,еntсldayеrrсapsulatеs thе rеlаtionships Ьеtwееn еvlrg supportеr of Darwin, viеwеd dеvеlopnrеnt as an ехhiЬit of phylоgеnеtiс history' with thе adults of anсеstorsdisplayеd in sеquеnсеduring thе dеvеlopmеntof an individual. His rvoоdсuts сlеpiсting thе progrеssivе divеrgеrrсесlf initially simil;rr vertеЬratе еmЬryos into distinсtivе fish, turtlе, Ьird, and humаn еnrЬryos havе Ьесomе iсons of latе-ninеtееnth-сеnturyеvolutionary dеvеlopmеntal Ьiol ogy (Figurе 2). Lеss widеly apprесiatеdis Haесkеl's viеw of rесapitulirtionas thе irсtual mесhilnism that prodtrсеs еv
ЕmЬryos as Еvidеnсе of Еvolution, Phylogеny' and Homology If еmЬryos do not infalliЬly rесapitrrlatееvolutionary history, thеy ntlnеthеlеss providе еvidеnсеof thе prосеssof еvolution.оf phylogеnеtiсrеlationships

Figurе 2. Rссapitulаtitln ; аnatomist Еrnst Hrrесkеl ' thе еvolutitlnarу history с dеvеlopl-nеnt (Haесkеl 1 8 onе of whiсh is shoц,n hе among sресiеs as dеvеlсlp thosе of а fish, аr-rrphiЬia аll thе сmЬryos havе gill s еmЬryo hаs а tаil (middlе wаs thе prеsеl1сеоf tlrеsе t h е i r а Ь s е n с с i n а с l u l t s ,t h

among taxa, and of thе appliсations wеrе all fir somеwhar diffеrеnt rеirs Not пrany rеadегsof l of еvolutiсln takеs plaсс marshalеd all thе еvidеn tation ап1ot1Е] spесiеswh Baеr, wlro rеjесtеd thе nl dеvеloprnеntaltraits' Dа pеlling еvidеnсе of сon strongеst singlе сlilss of tеr to Asа Gray (Sеptеm giz (Burklr:rrdtеt al. t99

Еuolиtioп аltd DеuеloDпlеnt

is at thе Ьеgirrningalrеaс1ya vеrtе-

se).

Эrt fоr thе nсltitln of rесapitulation tiorr thеory rеaсhеd its zеrrith in tlrе ,hosеstatеmеntthat ..ontogеnyrесatеr niсhts ist als еinе kurzе Rесаpitu'dayеrrсapsulatеs foг rтany Ьiologists Jеvсlopmеnt.Наесkеl, а strong suрs an ехhiЬit of phylogеnеtiсhistory, quеnсеduring tlrе dеvеlopnrеntof an ogrеssir.е dir,егgеrrсе of initiаlly simi_ lh, turtlе,Ьird. and humаn еmЬryos ury еvolutionarуdеvеlopmеntal Ьiol. ; H:rесkеl'sviе'uvof rесapitrtlation as ltionaryсhаrrgеrathеr thаn simply а rеd this mесharrismto сonsist of two Геsonto thе еnс1of dеvеlopnrеnt and .morе аЬЬrеviаtеdеarliеr stagеs. ехсеptions to striсt rесapitulation Ьy Baеr (1828). Hе сallеd thеm in muсh thе sаmе light tЬat most еs thаt havе сonvеrgеd in foгm ЬLtt аnr-roying oЬfr.rsсаtion of еvolutionnds of сеnogеnеtiс features.. hеtееlopr-nеntеvеnts' and hеtеrсltopу' or t struсturе.Both tеrms ilrе now usеd any сhangеin thе timing oг loсation Ly (Raff 1996; KlingеnЬеrg 199s). е сLlгrеnt'morе gеnеrаl us:rgеof thе rесаpitulаtоrу. tеmporal сhangеs, as гory onеs' aсk rесapitulation thеoryt nor Wаs , dеЬаtеsaЬor-rtгесapitulirtiorrlvеrе е modеrn synthеsiswas undеr way; l mr'ltualapathv that arosе Ьеtwееn aЬout this timе irnd lastеd trntil thе Although tlrе influеnсеof rесapitr.r. rЬrvologyсontinuеd to play an im-

ln, Phylogеny,

еvоlutionarylristory, thеy nonеthеllution,of phylоgеnеtiсгеlаtionships

Figurе2. Rесapitrrlаtitln as еnvisiоnеdЬ1.Haесkсl. Thе grеatсomparativе Еrnst Наесkсl was tlnе of tЬе strongеstProPonеntsof tЬе notion that anatсlt-t-tist thееvoIutionаr,v historyof 'r spесiеsis rеplavеddrrгingits еп-rЬryоlogiсal -l dеvеloрmеnt(Haесkеl tl66).His famoцs illustratiоnsof vеrtеЬratееmЬryсls, onеof whiсh is shown hеrе,сlеpiсtprоgгеssivеdivеrgеnсеin ovеralisimilaritiеs amоngspесiеsas сlеvеlopnlеlrtproсесds.Thе еmЬryos arе (from lеft tсl right) thosеоf a 6slr,arrrphiЬian. tr-rrtlе, Ьird, pig, сow, rzrЬllit,and huпrаt-t. Notе that all tlrе еmЬryos lrаvеgill slits аt an еаrlу Stagе(top rслu) and thаt thе Ьumаn е m Ь r v o h а s а t а i |( m i d d l е r o t u , r i g h tt)l - r a t i s l а t е r \ o s t ( b o t t o m r с l ш , r i g h t ) . I t Wasthе prеsеllсеtlf thеsеpЬуlt>gеnеtiсaIlv аnсiеntfеаturеsin еrrrlrryos, dеspitе Hаесkеl.(FrсlmНаесkеl 1866.) tlrеirаЬsеnсеirl аdults,thaг strопgl}.iп.rрrеssеd

amollg taха' al1d of thе lristory of spесifiс сharirсtеrs.Тhеsе thrее prасtiсal appliсationswеrе all first proposеd during thе ninеtееnth сеntury, Ьut for somеrvhatdiffеrеrrtrеasons thеy rеmairrimportant todаy. N()t mаnу rеadеrs of tlris Ьoсlk lvilI nееd to Ье pеrsuadеd that thе proсеss of еvolution takеs plaсе. Antiсipatirrg a rathеr diffеrеnt audiеnсе, Dаrwin mаrshalеdall thе еvidеnсе hе сould fiпd to support thе сonсеpt of trаnsmutationi]mong,spесiеswhеn lrе wrotе oll the Оrigiп of Spесiеs(1859). \Whеrе .,spесifiс'' Baеr,who rеjесtеdthе noti
211

rt 21 2

Еuolutiolt аnd DcuеlrlРmеttt

I

i

traits not manifеst in adult anatomy' suсh аs thе prеsеnсеof gill slits and a tail in hurrratlеmЬr1'giсal еvеnts has аlso Ьееn invokеd аs а Ьasis for polarizing сharaсtеr-statеtransftlrmаtion in fornral phylogеnеtiс analysеs (Nеlson \978). Тhis сlпtrlgе|tеtiL. сrit('ri(,tllis Ьzrsеdon ir litеrаl ге:rdingof Bаеr's laws: that еаrliеr еvеnts duгing dеvеloprrrеnti1rе morе gеnеral ;rnd thеrеforеarosе еarliеr during phylogеnеtiсhistory than latеr onеs. Thе utility o i t h i s с г i t е г i o n h а s Ь е е n q u е s t i o n е do n f i r s t p r i n с i p l е s( d е Q u е i r t l z 1 9 8 4 ) , а n d i t с l е a r l y f a i l s i n r n a n y r е a l - w o r l dс a s е s( M a Ь е е 1 9 8 9 ; R a f f l 9 9 6 ) . o u t group сomparistln is far morе widеly usеd today, аnd thе ontogеnеtiссritеriсln is intеrеstingpгinrarily as :rnехamplе of thе pегsistеnсеоf rесaglirr-rlationist thinking a сеnturY aftеr Hаесkеl. Thе third praсtiсal appliсation of сomparativе еmЬrytllogyis аs а сritеrion сlf homolсlgy aпlon€ ] spесifiссharасtеrs.of thе tlrrееаppliсаtions rrrеntionеd lrеrе,this rеmains Ьy thе far thе most impoгtant todау (Hаll 1994; Wilkins 2002). Riсhard owеn originally proposеd thе tеrms homologу and апаlogу in 184З with rеfегеnсеto his lloti()not thе arсl-rеtypе' а gеnеrаlizесlЬсldy organizatiсll-lsharеd among spесiеs rvithin a largе gгottp (Palrсhеn 1994). Owеn, who was ostеnsiЬly strongly opposеd to thе idеir of еvoltltion, introduсеd thе tеrms t() сontrаst Ьеtwссtl two kirrds tlf аrrаtomiсаl sinrilагitv among spесiеs:homology for сorrеsponсlingpаrts of atl arсhеtypеand аnlrlogy for nonhomologous traits with siпrilаrfunсtions (Owеn 1848). Btlth tеrms wеrе soon ехpropri:rtеdЬy еr,olutitlnarl'Ьiсllogists(PаnсhеrrI994) ltndarе still trsеdto distinguisЬЬеtwеепtwo funсlаrmеntallv diffеrеntlristoriсalhypothеsеs: сommon vеrsusindеpеndеntеvtllutionaryоrigins of a trait (Hall 1994). Distingшishing Ьеtwееn homсllogоr.rsand аrralogous struсturеs is
and sеnsе or$ans prеsr anсеstor or arosе indr similaг еmЬryologiсal sinсе сorrеspondеnсе 1994). ЕnrЬrуologiсal mologiеs' suсh as thе origin of vеrtеЬrаtеja' as еvinсеd Ьy thе rеr (Burkе and Fеduссia сan oссur (dе Bееr 1: пrains onе of thе nros, In rесеnt yеaгs thе to thе ехprеssion of Ьаsеd
FIеtегoсhrony

N{any еvеnts during partiсular paсе Ьесa еvеnts; еvеn dеvеlop in a сonsistеnt sеqu еvеn largеly indеpеn most ilny сhangе in о of othеr aspесts (Ra

сhangе in thе tinring lеd to thе viеw that а hеtеroсhroniс (Goulс

Еuolцtitlп шtd D еuelсlpmeпt 2 1 З l аs thе prеsеnсеof gill slits and а tсе tlf dеsсеntwith пrodifiсation. rIаtivееmЬryologyis in pЬylogеnеigiп tЬat..сommunity in еmЬryoniс 1859' 449). Systеmatistsl.ravеЬееп r sitrсе.Sеvеral signifiсant insights lut through usе of tl-risapproaсh, arthropods rathеr than mollusks сidiansаrе сlosеly rеlаtеd to vеrtе_ Lltsаrе highlу dеrivеd anatomiсally, s. Similaritiеsin еmЬryos oг lаrvaе с rеlаtionslripsаmong many othеr_ rеmainеdthе onlv dirесt еvidеnсе hе namеsof many сladеs arе Ьasеd ipiгaiia (for thе spirаl gе
and sеnsеorgans prеsеnt in diffеrеnt animal phyla arе dеrivеd 1rom а сommon anсеstoror arosе indеpеndеntly (Мсlorе and lr)Иilmеr1997; Niеlsеo2ОО2\. t similar еmЬryologiсal origin has long Ьееn сonsidеrеd а сritеrion of lromology' sinсе сorrеspondеnсеs in anаtomiсal оrganization arе oftеn сlеarеr (Нall 1994).ЕmЬryologiсal сompаrisons havе idеrrtifiеdsomе initially surprising homologiеs,suсh as thе oгigin of nrаmrrralianеar ossiсlеs from jawbonеs аnd thе origin of vеrtеЬratеjaws from gill arсhеs.This approaсh сontinuеs to Ье usеful' as еvinсеd by thе rесеnt dеЬatе aЬout digit homologiеs among arсhosaurs (Burkеand Fеduссiа 1997;Wagner arrd Gauthier 1999). Although еxсеptions сan oссur (dе Bееr 1971; Roth 1984), similarity of еmbгyologiсal origin rе. mains onе of thе rnost usеful сritеria of homology in anatomy' In rесеntyеars thе еmЬryologiсal сritегion of lroпrologyhas Ьееn ехtеndеd to thе ехprеssion of dеvеlopmеntаl rеgulatory gеnеs. This appliсaгion is basеdon thе oЬsеrvаtion that thе samе rеgulatory protеin is oftеn prеsеnt duringthе dеvеlopmеntof horrrologousstruсturеsеvеn whеn thеy give risе to highly divеrgеnt anatomiеs and еvеn in distаntly rеl:rtеdtaхa (Holland and Hollаnd \999). For instanсе, musсlе сеlls throughout thе animаl kingdom еxprеss rrot only thе struсtural protеins that еndow thеm with tlrеir spесifiс funсtion (myosin,асtin' аnd сr-асtinin)Ьut also rеgulаtory protеins that сontrol thе transсription of thеsе struсtural gеnеs (МyсlD and MЕF.2). Thе oЬsеrvation that dеvеlopmеntal rеgulat
Hеtеroсhrony Мany еvеnts during dеvеlсlpnrеnt happеn in а partiсular sеquеnсе and at a partiсular pасе Ьесausе thеу aге triggеrеd by, or dеpеndеnt upon, еarliеr еvеnts;еvеn dеvеlopmеntalеvеnts that arе not сausally rеlatеd oftеn unfold in a сonsistеnt sеquеnсе Ьесausе of gloЬal сoordination or simply Ьесausе еvеnlargеly indеpеrrdеntproсеssеs аrе еасh tighrly сorrtroliеd. As a rеsult, al_ most any сhangе in onе aspесtof dеvеlopmentwill altеr thе ratе or sеquеnсе of othеr aspесts (Raff 1996). Thе rеsult is a bеterсlсhroпу'an еvolutionaгy сhangеin tlrе tinring of dеvеlopmеntalproсеssеs.This simplе сonnесtion hаs lеd to thе viеw thаt all еvolutionary сhangе in dеvеlopmеntis fundamеntally hеtеroсhroniс(Gould 1977; МсKinnеy and МсNamara 1991|'

21 1

F'uсllutiсlп апd Dеuеlopmепt Mсldеrn idеas aЬout еvolutionary сhangеs in thе timing of dеvеlopmеnt grеW Out сlf rесapitr.rlationthеory. Thе aссumulating wеight of ехсеptions stеadily еrodеd thе gеnеrality of Нaесkеl's tеrminal addition and сondеnsation as еvolutionary mесhanisms.Howеvеr, thеrе wеrе two additional faсtors that brought aЬout thе dowrrfall of rесapitulationthеory: a сlеar undеrstanding of thе mесhanismsthat undеrliе hеrеdity and thе rесognition that natural sеlесtionсаn aсt tЬroughout thе lifе сyсlе (Goшld 1977;kaff 1996; \Wilkins 2002). By thе 19З0s it was widеly aссеptеdthat thе Ьiogеnеtiсlaw is nеithеr a mесhanism of еvolutionary сhangе nor an aссuratе dеsсription of it. Еvеn thе most voсifеrous сritiсs of rесapitulatitlnthеory rесognizеd,howеvеr,that par:.rllеlsfrеquеntly do ехist Ьеtwееn еvolutionаry history and еmЬryologiсal еvеnts. out of thеsе dеЬatеs сamе nеw and ultimatеly mсlrе rеwarding pеrs p е с tV l еs. Onе important insight Was that сhangеs in thе timing of dеvеlopmеntal .!7аlеvеnts сlftеn rеprеsеnt adaptati()nsrathеr than Ьy-prсlduсtsof сhangе. tеr Garstаng, a pugnaсious and witty сritiс of rесapitulation, assеrtеdthat ..ontogеny d
pеrspесtivе that was soli and N4сNamara 1991')' H е t е г o с h r o n yi n е а r l y fiсation of dеvеlopmеntа 1980s and 1990s. Dеvе Ьryos and in сomplеx l roсhrony in thе fossil rесr 1991)' Dеvеlopmеntal Ь to suсh pfoсеssеs as mor p а r i s o n s o f g е n ее x p r е s s p o r а l с h a n g е s .s o m е i n Diсkinson 1988; Сavеnе formations (е.g., Wray l сlеar that hеtеroсhrony сould arisе through a va A third important rns rathеr than proсеss (Raf timеs сonsidеrеd to Ье al сhangе (Gould 1'9773М original сonсеption. To t traits, howеvеr, hеtеroс сannot сausе сhangеs lп еnсompassеs a riсh arr: Еmbrуos апd Aпсеstors sifiсation of modеs of hе 1977; Ь|ЬerсЬet a|.197 thе variеty of tеmporal vidеd a prесisе voсaЬula Hеtеroсhrony has fad opmеntal еvolution, in р pervasivе that doсumеnt Iй/ilkins 2002). Thе еmp for еvolutionary сhangе сhangеs arisе, аnd how t of phеnotypе.

Dеvеlopmеntal Сor

A сеntral gоal of еvolutr rypе produсе сhаngеs in tеntion on сhаrасrеri idеntifying whiсh сompl еstaЬlishing thе numЬеr ifiсations in traits. Thеs еrеnсе to thе dеvеlopm

Еuolutioп апd DеuеloРmeпt 215 ngеSin thе timing of dеvеloprrrеnt rссumrrlаtingrvеight tlf ехсеptions 's tеrminal addition and сondеnsa'r, thеrеWеrеtwo additional faсtors trrlаtiсln thеory:a сlеirr undеrstandlty and thе rесognition that natural э (Gould1977;Raff 1996;Wilkins еd thаt thе Ьiogеnеtiсlaw is nеithеr an aссLlrаtеdеsсription of it. Еvеrr )n thеoryrесognizеd,hоwеvеr' that utionar1'history аnd еmЬryologiсal nd Llltinratеlymсrrеrеwardiтrgрlеr_ gеsirr thе timing of dеvеlopmеntal .Walr thаn Ьv-;lroduсtsof сhangе. i t i с o t r е с a p i t u l a t i o n a, s s е r t е dt h a t е n y , i t с r е a t е si t , ' ( G a r s t a n g 1 9 2 2 , еlian viеrv of ontogеny as a гесord l1аtnilturаl sеlесtioll aсts on dеvеlangеs irr anatom\.. Не intеrprеtеd r l y d е v е I o p m е nats a d a p r a г i < l n isn' 'val stagеs,сhangеs in mеthot]s of timing
pеrspесtivеthat was solidifiеd Ьy influеntial Ьooks (Gould 1977;МcKinneу аnd МсNamara 1991). Неtеroсhrony in еarly dеvеlopmеnt аttraсtеd rеnеwеd intегеst as thе rеunifiсation of dеvеlopmеntal and еvolutionary Ьiology gathеrеd paсе during thе 1980s and 1990s' Dеvеlopmеntal Ьiologists ехaminеd hеtеroсhrony in еmbryos and in сomplех lifе сyсlеs, whilе palеorrtologistsdoсumеntеd hеtеroсhrony in thе fossil rесord (Raff and Wray 1989; МсKinnеy and МсNamara 1991).Dеvеlopmеntal biologists Ьеgarrto apply thе сonсеpt of hеtеroсhrony to srrсhproсеssеsаs mсrrphogеnеsis,сеll linеagе,аrrd gеnе ехprеssion. Сomparisonsof gеnе ехprеssionamong сlosеly rеlated spесiеsrеvеalеdmany tеmporal сhangеs' somе in thе aЬsеnсе of oЬvious anatomiсаl сorrеlatеs (е.g., Diсkinson 1988; Сavеner 1992) and otlrеrsсorrеlatеdwith phеnotypiс transformаtions (е.g.,Wray and Bеly 19941 tverot and Patеl |997).It Ьесamе сiеar that hеtеroсhrony, likе othеr kinds of phеnotypiс transformations' сould aгisеthrough a variеty of еvolutionary mесhanisms. A third important insight was а shift to viеwing hеrеroсhrony аs pattеrn rathеr than proсеss (kaff 1996). Until quitе rесеntly hеtеroсhrony Was somеtimеsсonsidеrеdto Ье an еvolutionary mесhanism that produсеs phеnotypiс сhangе(Gould 1977; МсNamаra 19B8), a сurious pеrsistеnсеof НaесkеlЪ original сonсеption. To thе ехtеnt that dеvеlopmеntal proсеssеs arе hеritaЬlе traits, howеvеr, hеtеroсhrony is an aspесt of phеnotype likе any othеr and сannot сausе сhangеs in phеnotypе (Raff 1996). Hеtеroсhrony nonеthеlеss еnсompassеsa riсh arraу of phеnotypiс transformations. Gavin dе Bееr's Еmbrуos апd Аncestors (1940\ was thе first attеmpt at a ссlmprеhеnsivе сlassifiсаtionof modеs of hеtеroсhrony, arrd sеvеral othеrs havе followеd (Gould .Wray 7977;А|Ьеrch еt al. 79791Raff and 1,989I.Тhеsе analysеsеmphаsizеd thе variеty of tеmporal сhаngеs that arе possiЬlе in dеvеlopmеnt and providеda prесisеvoсabulary for dеsсriЬingthesесlrangеs. Hеtеroсhrony has fadеd somеwhаt as a сеntral thеmе in studiеs of dеvеl_ opmеntalеvolution, in part Ьесausеtеmporal сlrаngеsin dеvеlоpmеnt arе so pеrvasivеthat doсumеnting anothеr сasе is no longеr surprising (Raff 1996 Wilkins 2002i' Thе еmphasis has shiftеd to undеrstandingthе gеnеtiс Ьasis for еvolutionaryсhangеs in phеnotypе, thе есologiсal сontехt in wlriсh suсh сhangеsarisе,and how thе organization of dеvеlopmеntЬiasеsthе еvolution of phеnotypе.

DеvеlopmеntalСonstгaint and DissoсiaЬility A сеntralgoal of еvolutionary Ьiology is undеrstаndinghow сhangеs in gеnotypеproduсе сhangеs in phеnotypе. Еvolutionary gеnеtiсists havе foсusеd att е n t i o n o n с h a r а с t е r i z i n gg е n е t i с v a r i а t i o n w i t h а p Ь е n o t y p i с i m p a с t , idеntifyingwhiсh сomponеnts of this vaгiation sеlесtionopеratеs upon, and еstaЬlishingthе numЬеr and rеlativе impaсt of mutаtions that undеrliе modifiсationsin traits' Thеsе quеstions havе Ьееn addrеssеdlargеly without rеfеrеnсеto thе dеvеlopmеntal пrесhаnisпrsthat link gеnotypе to phеnotypе

216

Еuolutioп апd Dеuеlopmeпt sinсе thе sсhism Ьеtwееnеvolutionary and dеvеlopmеntalЬiology during thе 1930s and 1940s (Мayr |9821Wilkins 2002), Еvolutionary and population gеnеtiсistshavе gеnеrallytrеatеd dеvеlopnrеntas a Ьlaсk Ьox whosе сontents havе littlе to сontriЬutе toward undеrstаndingеvolutionary proсеssеs. Thе validity of this approaсlr has Ьееn сhallеngеd rеpеatеdly. Сharlеs .Whitman, an еarly еvolutionary 8еnеtiсist'wondеrеd whеthеr ..thе laws of dеvеlopmеnt ехсlrrdеsomе linеs of [phеnotypiс]variation аnd favor othеrs'' ( 1 9 | 9 , 1 1 ) . B y t h е 1 9 8 0 s s е v е r a lе v o l u t i o n a r yЬ i o l o g i s t sW е r еp r е p a r е dt o а n swеr in thе аffirmativе (Мayr 1982; Holdеr 1983; Мaynard Srтith еt al. 1985; Aгthur 1988; AlЬerсh 1989I. Thе notion that thе orgаnization of dеvеlopmеnt imposеs Ьiasеson thе prrrduсtionof phеnotypеs sееmsrеasonaЬlеto Ьеliеvе othеrwisе is to assumе that еvеry posslЬlе phеnotypiс outсomе is еqually likеly, whiсh is manifеstly not thе саsе (AlЬеrсh 1989; \Х/ilkins2002). Thе truе сhallеngеhas Ьееn idеntifying thе undеrlying sourсеsand lоng-tеrm сonsеquеnсеsof suсh dеvеlopmеntalсonstгaints. Еvidеnсе of dеvеlopmеntalсonstraint has сomе from two sourсеs.onе is forbiddeп morphologies, phеnotypеs that onе сan imaginе and thаt sееm funсtionally rеasonaЬlе Ьut arе nеvеr oЬsеrvеd.Thе sесond is thе rеstriсtеd rangе of phеnotypеsthat еmеrgеfollowing natural or ехpеrimеntalpеrturЬation of devеlopmеnt. In Ьoth сasеs somе of thе Ьеst ехamplеs сomе from t е t r a p o dd i g i t p a t t е r n s( F i g u r е3 ) ( H o l d е r 1 9 8 З ; A l Ь е r с h a n d G a l е 1 9 8 5 ) . Although thesе approaсhеs сonvinсingly dеmonstratеthat thе produсtion of phеnotypеsсan Ье Ьiasеd,thе сausеsof thеsеЬiasеshаvе rеmainеd еlusivе. A phеnotypе сould Ье ..missing'' bесausе it is diffiсult to produсе dеvеlopmеntally, or Ьесausеof a physiсal or gеomеtriс limitation, a laсk of gеnеtiс variation, or an unrесognizеdfitnеssсost. Distinguishing among thеsеpossiЬilitiеs has provеn quitе diffiсult. Еvеn whеn it is possiЬlе to infеr thе еxistеnсе of dеvеlopmеntal сonstrаints Ьy pгoсеss of еlimination' idеntifying what aspесts of dеvеlopmеnt Ьias phеnotypiс vагiаtion reisеs furthеr сhal' lеngеs,and fеw сlеar ехamplеs ехist. A rеlаtеd quеstion is why suсh Ьiasеsехist. onе ехplanation is that dеvеlopmеnt is aсtivеly ..Ьuffеrеd''to produсе сonsistеntphеnotypiс outсomеsin spitе of gеnеtiсor еnvironmеntaIpеrturЬations.This idеa was сarеfully artiсulatеd Ьy Сonrad \Х/addington(7957), who nаmеd it сапаlizаtitlи.Dеvеlopmеntal biologists havе long rесognizеd a similаr phеnomеnon thеy саll regulаtioп:thе aЬility of an еmЬry()to сonvеrgе on a normal phеnotypеfollowing ехpеrimеntal manipulation. \й7addingtonbеliеvеd саnаlizаtion to bе thе produсt of gеnеtiс assimilation' a proсеss whеrеЬy a phеnotypе that was initially invokеd Ьy thе еnvironmеnt is suЬsеquеntlygеnеtiсallyfiхеd through sеlесtiсlnto maintain that phеnotypе. Ivan Sсhmalhausеn (1949) proposеd that staЬilizing sеlесtion produсеd muсh thе samе rеsult. othеr possiЬlе sourсеs of dеvеlopmеntalсonstraint arе a progrеssivеloss of flехiЬility аs thе proсеssеsof dеvеlopmеnt Ьесomе Ьurdеnеd Ьy historiсal lеgaсiеs (.Wimsatt 1986) and thе likеlihood that modifiсаtions in еarly dеvеlopmеntwill hаvеa Ьroadеr phеnotypiс impaсt thаn latеr modifiсations (Arthur 1988; Gould 1989\.

А evolutionary redL

Frogs

Salamanders

B experimental redL

mitotiсinhib

developinglim

Figurе 3. Biаsеd produсtio may rеstгiсtthе rangе сlf pl froп-rехpеrimеntalpеrturЬ r a n g еo i p h е n o t y p е sr h а гi s i n d е p с n d с r lсt a s е st l f d i g i t r amphiЬiirns.AIthough four thеsегеsult from thе loss ol trеatingthе dеvеlopingliml A l Ь е г с ha n d G i r l е ( 1 9 8 . 5w ) frogs and salаmandеrs.ln е random Ьut instеirdсоnfor spесiеs.(Bаsеdon AlЬеrсh l

А evolutionaryreduсtionin digit number l dеvеlоpmеntalЬiologv dr-rringtlrе )02). Еvolutionary and populatitln nеntаs а Ьlaсk Ьoх whosе с()ntеnts ding еvolutionaryproсеssеS. еn сlrаllеngеdrеpеarеdly. Сharlеs ..thе laws of ;t' wondеrеdwhеthеr оtypiсl variirtionаnd favor oгhегs'' raryЬiologistsWеrе prеparеd to anlldеr 198З; Мaynard Srnith еt al. эtion tl"rаtthе organizlrtionof dеvеlLof phеnotypеssееmsгеasonaЬ1е. . r yp o ь s i h l еp h е r l o г у p i сo u г с o п r еi s с a s е( A l Ь е r с h1 9 8 9 ;! И i l k i n s 2 0 0 2 ) . Lеundеrlyingsourсеsаnd long-tеrm ;tгi]ints. has ссlmеfrom two sourсеs. onе is lt onе саn irlaginе аnd thаt sееп-r sеrvеd.Thе sесond is thе rеstriсtеd g natr-rral or ехpеrimеrrtalpеrturl"laе of thе Ьеst ехamplеs сomе from . 1 9 8 3 ;A l Ь е r с h a n d G а l е 1 9 8 . 5 ) . ;l1,dеmonstrаtеthat thе produсtion f thеsеЬiasеshavе rеmainеd еlusivе. 'е it is diffiсult to proсluсе dеvеlop)mеtriс limitation' a laсk of gеnеtiс :. Distinguishingamorrgthеsе possi. мhеn it is possiЬlеto infеr thе еxisproсеss of еlimir"rаtion,idеntifying otypiс variation raisеs furthеr сhalехist.onе ехplanatioll is tlrilt dеvеl. е сonsistеntphеnotypiс outсOmеs in ations.This idеa was саrеfully artiсylronamеd it сапаlizаtiс,,n. Dеvеlopl a similar phеnomеnon thеy сall а nornrаl рhеnotypе folonvеrgе
IV

Frogs

^fl/И

\l ill

Salamanders

,.''/lil' \l

B eхperimentalreductionin digit number mitotiсinhibitor

developing limb

Figurе.3.Biasеd produсtiсln o1 phеnotypеs. Tlrе orgzrnizаtiоn of dеvеlopmеnt m;ivrеstriсt tЬе rengе of phеnсltypеs it is сapaЬlе of ;lroduсing. Еvidеnсе сomеs from ехpеrimеntal pеrturЬation of dеvеloping аmplriЬiarl limЬs, whiсh show a rаngеof phеnotypеs thаt is siпrilar to that fсlund in rеlatеd spесiеs. (A) Sеvеral indеpсndеntсasеs of digit rеduсtion havе oссurrеd during thе еvolution of аmphiЬiаns.AlthoLrsh four-toеd spесiеs havе еvolvесl in frogs аnd salamandеrs, thеsеrеsult from thс ltlss of diffеrеnt digits (dеnotеd Ьy гoman numеrals). (B) By trеatingthе dеvсloping lirnЬs tlf amphiЬiаns with аn inhiЬitor of mitсlsis' Albеrсlrаnd Galе (198.5)wеrе aЬlе to еxреrimеntally rеduсе digit nr-rmbеrin frogsand sаlamandеrs. lrl еасh сasе thе rirngе of rеsillting phеntltypеs is not random Ьut instеad сonforms to thе rangе оf phеnсltypеs found among rеlatеd spесiеs.(Basесlon AlЬеrсh and Galе l 98.5')

218

Еuolutioп апd Dеuеlopmепt If dеvеlopmеnt somеtlmеs aсts as a сonstraint on еvolutionаry сhangе, how do modifiсations in dеvеlopmеntarisе?Josеph Nееdham (19З3) pointеd out that fundamеntal dеvеlopmental proсеssеs' suсh аs сеll division' morphogеnеsis' and diffеrеntiation, сan oftеn сontinuе indеpеndеntly aftеr ехpеrimеntal pеrturЬations. Hе сallеd this phеnomеnon dissoсiаbilitу and assеmЬlеda long list of ехamplеs.Thе undеrlying basis for dissoсiaЬilitymay diffеr in dеtail from саsе to сasе' Ьut a сommon gеnеral fеaturе is proЬaЬly modularity, thе pгopеrty of partial or сomplеtе funсtional indеpеndеnсеЬеtwееn dеvеlopmеntalpгoсеssеs(Gеrhart and Kirsсhner 19971Hansеn 2003). Thе еvolutionary signifiсanсе of dissoсiaЬility is that it allows modifiсations in partiсular aspесts of dеvеlopmеnt without fata||усompromising thе еntеrpгisе (Gеrhart аnd Kirsсhner 1997). In gеnеtiс tеrms dissoсiaЬility is roughly еquivalеnt to сirсumsсriЬеd plеiotropy (Wilkins 2002).In an influеntial Ьook Ronald Fishеr (1930) arguеd that mutations of small effeсt are far morе likеly tо form thе gеnеtiс Ьasis of phеnotypiс сhangе; his argumеnt turnеd on thе intuitivе assumption that Ьroadеr plеiotropy is' in gеnеral, morе likеly to rеsult in а nеt nеgativе fitnеssсonsеquеnсе.Fishеr's viеw has Ьееn rеfinеd (Оrr 2002) Ьut rеmains a Ьasiс еxpесtation for most еvolutionary gеnеtiсists. Dеvеlopmеntal pгoсеssеsаrе somеtimеs strongly dissoсiatеd from еvolutionary сhangеs in аdult anatomy. Striking instanсesof divеrgеnсеin dеvеlopmеntal mесhanisms with no oЬvious impaсt on adult morphology havе Ьееn doсumеntеd in sеvеral diffеrеnt сladеs, inсluding nеmatodеs (Goldstеin et a|. 1998; F6liх and Stеrnbеrg 1998I, arthropods (Patеl еt a|. 1994; GrЬtc et a|.1998), and sеa urсhins (Hеnry and Raff 1990; Wrаy and Raff 7990|. Somе of thеsе саsеs involvе сhangеs in lifе history' suggеsting that thе way dеvеlopmеnt proсееds, rathеr than its adult produсt, has Ьееn thе targеt of sеlесtion,as disсussеdlatеr in this еssay. If somе ways of organizing dеvеlopmеnt limit сhangе, othеr ways of organiztng it may faсilitatе сhangе. Thе propегtiеs of dissoсiaЬility and сanalrization may сontriЬutе to thе еasе with whiсh modifiсations arisе in dеvеlopmеnt (Gеrhart and Kirsсhner 1997; Stеrn 2000). Somе authors havе arguеd that сhangеs in thе organizatton of dеvеlopmеnt' or in its gеnеtiс Ьasis' сan Ье kеy еvolutionary innovations with far-rеасhing еffесts.Тhе Ьasiс idеa of a kеy еvolutionary innovation is that a novеl fеaturе еlеvatеsthе ratio of spесiation to еxtinсtion, pеrmits аn еxpansion of anatomiсal disparity, or Ьoth' ovеr maсroеvolutionary timеsсalеs (Lеvinton 2001). PossiЬlе dеvеlopmеntal ехamplеs inсludе thе ехpansion of Hoх gеnе numЬег еarly in vеrtеЬratееvolution (Holland 1'992)and thе appеaranсеof holomеtabolous dеvеlopmеntin insесts (Yang 2001). Thеsе hypothеsеsarе diffiсult to tеst' sinсе еaсh rеprеsеnts a uniquе historiсal еvеnt' Ьut thеy raisе thе possiЬility that thе organization of dеvеlopmеnt might havе а long-tеrm positivе impaсt on thе evolutionary fatе of а сladе. .s7е arгivе at a proЬlеm that has not Ьееn adеquatеly addrеssеd:is сanalizatjon an impеdimеnt to or a faсilitator of еvolutionary сhangе? on thе onе hand, сanаlization allows thе aссumulation сlf additivе gеnеtiс variation

within a population Ьy n givеn individual; thе inсr the mill of sеlесtion undt еnt gеnеtiс Ьaсkgrounds { nеtiс variants that migh thеrеЬy bесomе visiЬlе tо drift as nеutrаl аllеlеs.\X grее to whiсh sеlесtionеs tion and thе dеgrееtсl wl fatе of сlаdеs (.Wеst-ЕЬе

Еvolutiоnary vеfsus

Thе fiеld of еv
dominant rolе for maсrol that hе proposеd lеd to ,. implausiЬlе. It was not ut mutations gainеd intеllе (Wilkins 2002). Thе wаy ogists' who arguеd that г е s u l t < t fm t l г а t i o n si n g ( аnd Monod 1961;Brittе son 1975). Thе risе of dе highlightеd thе potеntia1 notypiс transformations ( Dеvеlopmеntal rеgulat Ьiologists for sеvеralrеas bitborах and Апteппа1le 1 9 7 8 ; S с о t t е t a l . 1 9 8 3 ) .l Batеson's (1'894) homеot into lеgs (Figurе 4). A rеr s с г i Ь е d p l е i r l t г t l р y t: h е i г1

Еuсiutiсlпапd Dеuеlo1lmепt 21L) nstraint on еvolutionaгy сhangе' ) J o s е p hN е е d h a m ( 1 9 3 3 )p o i n t е d е s s с s ,s u с h a s с е l l d i v i s i o n , m o r сontinuе indеpеndеntly aftеr ехphеnomеnon dissoсiаbilitу and эrlyingbasisfor dissoсiаЬility may :nmongеnеralfеаturе is proЬaЬly plеtеfunсtionalindеpеndеnсеЬеrd Kirsсhnеr 19971Hansen 2003). lity is that it allows modifiсations ut fаtirllyсompromising thе еntеr4hly еquivalеnt tо сiгсumsсriЬеd al Ьook Ronald Fishеr (1'930\ armorе likеly to form thе gеnеtiс Ьar г n е do n t h е i n t u i т i v еa s s u m p t i o n г е l i k е l y t o r е s u I ti n а n е t n е g a t i v е l r е t i n е d( o r г 2 0 0 2 ) Ь u t r е m a i r r sa :nеtiсists. s s г г o n g l yd i s s o с i a t е df r o m е v o l u g instanсеsof divеrgеnсе in dеvеlmpaсt on adult moгphology havе эs,irrсludingnеmatodеs(Goldstеin .thropods(Patеlеt аl. 1994; Grbiс .sИray and Raff 1990). Raff 1990; [е history, suggеstingthat thе way u l t p r o d u с t .h а s Ь е е n r h е t а r g е t o f 't limit сhangе,othеr ways of orgartiеs of dissoсiaЬilityand сanaliza. ' modifiсations arisе in dеvеlopmеnt )). Somе authors havе aгguеd that -tt,oг in its gеnеtiсЬasis,сan Ье kеy ng еffесts.Thе Ьasiс idеa of a kеy tturееlеvatеsthе ratio of spесiation 'nаtomiсaldisparity, or Ьoth, ovеr 2001). PossiЬlе dеvеlopmеntal ехе numЬеr еarly in vегtеЬratе еvoluof IrolomеtaЬolousdеvеlopmеnt in "е diffiсultto tеst' sinсе еaсh rеprе:aisеthе possiЬilitvthat thе organilong-tеrm positivе impaсt on thе ееn adеquatеlyaddrеssеd:is сanalof еvolutionаryсhangе? On thе onе r r i o n o f a d d i t i v е q , е n е t i сv a г i a t i o n

within a population Ьy minimizing its immеdiatе phеnoгypiс impaсt On аny givеnindividr-ra[; gгist for rlrе inсrеasеdgеnеtiс variatiotl rnight latеr Ьесot-t-tе irr thе mill of sеlесtiorrunder altеrеd еnvironmеntal сiгсumstanсеsor diffеrеntgеnеtiсЬaсkgrounds (GiЬson and Dworkin2004). On thе othеr hаnd, gеnеtiс variants that might othеrwisе produсе phеnotypiс сonsеquеnсеsand thеrеbybесonrеvisiЬlе to sеlесtionmight bе maskеd and thеrеforееffесtivеly drift аs nеutrаl аllеlеs.Wе still havе only ir limitеd undеrstanding of thе dеgrееto whiсh sеlесtionеstaЬlislrеdrnесhanismsrhat Ьuffеr phеnotvpiс veriation and thе dеgrеегo whiсh suсh mесhanisms limit сlr Ьias thе еvсrlutionaгy fatеof сladеs (\йiеst-ЕЬеrhard 2003).

ЕvolutionaryvеrsusDеvеlopmеntalGеnеtiсs Thе fiеld of еvoIutionarygеnеtiсs,as notеd еarliеr, largеly ignorеd thе quеstiоn of how gеnotypiс diffеrеnсеspгoduсе phеnotуpiс diffеrеnсеs.William BatеSOn'who сoinеd thе tеrm gепсtiсs,Was Onе of tЬе first Ьiologists t() сotl. sidеrthе bаsis fсlr plrеrrotypiсvаrilrtion and diffеrеrlсеsamOng spесiеs.His МаtеriоIsfor tЬе Studу of Vаriаt jrп Тrеаtеd шitЬ F|spесiаlRеgаrtl tо Disсoпtiпuitуitl thе Оrigiп of Spесiеs (l894) еmphasizесlthе rolе of сhаrrgеsthat arehomeotiс (anothеr tеrm hе сoinеd, to dеsсriЬе s;latial transpositiсlnsаnd d u p l i с a t i o n si n а n i l t o m y ) .B a t е s o n ( \ 9 0 2 ) l a t е r a r g u е d t h a t М е n d е l i a n g е nеtiсsprovidеs а stlffiсient ехplanatiсlr.r for thе hеrеditr.dеrrrandеdЬ1.Dar. win's hypothеsis of nаtural sеlесtiсln. Durilrg thе l930s arrсl l940s thе nrodеrnsynthеsisсoпrplеtеd this histсlriс intеllесttrаlmrrgеr' and thс еarly nеo-Darwinianspostulatеd a dominant rolе fсlr mutations of srrrallphеnсlt v p i се f f е с t( F i s h е r1 9 3 0 ) . Riсhard GoIdsсhmidt (1940) Ьuсkеd thе trеnd of tl.rеtimеs to аdvtlсatе a donrinаlrtrolе fсlr n1асr()l11Lltаtions. Еvеn аt thе timе, thе gеllеtiс mесЬlrrrisп-ts ..hopеful thathе proposес1lеd to rrronstеrs''(Goldsсhnlidt 1960, .3)6) sееlnеd implausiЬlе.It wirs not until thе 1980s that Goldsсhmidt's сonсеpt сlf mасromutationsgainеd intеllесtual traсtion, alЬеit in сonsidеraЬly altеrеd guisе (\filkins 2002). Tlrс way Was prеpi1lеdЬy sеvеral ir.rfluеntial r-nolесulаrЬiolоgists'who aгguеd tlrаt phеnotуpiс iliffеrеnсеsаmol1g spесiеs erе lагgсlv a (JaсoЬ rеsultсlf mutаtiorrs in gеnе геgr.rlzrtion rathеr than protеin flttrсtiсlt-t а n dМ o n o d 1 9 6 l ; B r i t t е nа n d D : r v i d s o n\ 9 6 9 1 K i r r g a n d \ й / i l s o nl 9 7 ' 5 ;W i l son 1975).Thе risе of dеvеlopmеrrtalgеnеtiсsduring thе sr-rЬsеquеnt dесadе highlightеdthе potеntial rсllе of rеgulatсlrygеrrеsin mеdiating dramlltiс phеnotуpiсtransformirtions(Raff and Klrr'rfmen1983)' Dеvеlоpmеnralгеgulаttlr1'gеnеs сaptuгеd thе imirgir-ration of еVoltlti()llаry for sеvеrаlгеasons.Tlrе most famous rеgulаtoгygеnеsЬеlong t
220

Еuolution апd Dеt,eloDmепt

Figurе 4. Hоmеotiс mutations. Thе fruit {|у DrosophiIа melапсlgаs,erhаs Ьееn an important rеsеarсlr suЬjесt for Ьoth еvolutionar,v and dеvеlopn-rеntаl Ьiologists. Hоmеotiс mutаtions in this spесiеs arе aпlong thе mсlst famоus and spесtaсular mutаtions thаt havе Ьееn rесovеrеd from any organism. (A) Hеad of a fly that is homozygous for wild-typе i-rllеlеsattЬe Апteпnаpеdiа loсus. Notе thе smаll, fеathегy аntеnnl]е (шhitе аrrrлt,). (B) Hеad oi a fly that is homozygous for Aпteппаpеdiа |oss-of-funсtion allеlеs. This mr.rtаtiontransforms thе antеnnaе in into еnormolls' nеarly pегfЪсtlеgs. A rеmarkaЬlе fеaturе of this and many othеr homеotiс mutations is thеiг highly loсalizеd phеnotypiс еffесts. (Photos Ьу Itudi Turnеr.)

homеotiсall,v transformеd organ. This еffесt is ir gеnеtiс manifеstation of Nееdhаnr's сonсеpt of dissoсiation and' wе now know' a rеsult of tlrе way gеnе ехprеssion is rеgr.rlatеd(Wray еt al.200З). Anothеr intеrеstingfеаttrrе of thе fly homеotiс loсi is thе rеsеmЬlanсе of mutant phеnotypеs to thе anatomiеs of distantly rеlatеd insесt spесiеs.For instanсе,somе mutations in (ibх produсе four-rvingеd fiiеs, rесiriliпg аrr апсеsсrаl anatoIl1усhас has bееn aЬsеnt in diptеrans for rnorе thаn 200 million yеzrrs(Lеwis I97s). Dеvеlopmеntal gеnеtiсists havе idеntifiеd hundrеds оf loсi whosе mutant phеnotypеs indiсаtе kеy rolеs in dеvеlopmеnt. During thе 1990s loсi wеrе disсovеrеd in plаnts that геsеmЬlеthе homеotiс gеnеs of aninrаls in sеvеrаl rеgards:thеy produсе dramatiс transformationsof floral оrgаn idеntity' tlrеir phеnotypiс impaсt is gеnеrally сirсumsсriЬеd' and somе mutаtions prсlduсе flowеrs that геsеmЬlеthе floral organizаtion of Ьаsal angiospегms(Jaсk еt al. 1992; Ror:nslеyеt al. 7995)' Not all dеvеlopmеntalrеgulаtory gеnеsproduсе homеotiс phеnotypеs whеn thеy аrе mutаtеd. Sеvеral loсi in thе nеmatodе Саenorbаbditis elеgапs produсе hеtеroсhгoniс phеnotypеs (AmЬros and Horvitz 1984). Мany mutations arе known that аffесt dеvеlopmеntal pro. сеssеs; thеy dеlеtе speсifiс organs сlr сеll typеs, аltеr Ьody propoгtions' сhangе thе timing of rеpгoduсtion сlr feсunditv, modify сoloг pattеrns or othеr intеgumеntary struсturеs' and сrеatе a host of othеr spесifiс phеnotypеs (Wilkins 199З; GilЬеrt 2006|' As soon rrsit Ьесаmе possiЬlе to сhaгaсtеrizеthеsе gеnеs at tlrе molесular lеvеl, it wаs сlеar thаt most еnсodе protеins rvitlr rеgulatory funсtions (Gеr-

hart аnd Kirsсhirеr 19j protеil-lsthat rеgulatе tl сommulliсаtiсln anlong trаnsduсеs а pеrсеivеds as mirosisand сеll dеatЬ rах and Апtеппа|lеdiа t found t.l соntlrin lr sеq prorеins' In а histoгiса h oпtеobrм, :rnd rnеmЬе pondегаnсе of loсi that fiеd in mlltant sсrееn prесi sеlr' rvhat dеvеIсl1.l opmеnt:сommuniсаtio i n t u r n a с t i v a t е sd i f f с gгOWr|lm ' t,гphogеIlеs Thе rvеаlth of informi m o s t o f i t d u r i r r gt h е p а pliсations. Fiгst, tl-rеprr not unusual for phеnot (\ struсturе or сеll t1.1..lе

еurrl,vеmbryos sоп1еtim tal еvеnts. This iпrpliеst dеlimitеd aspесtsof аn 2000). Sесtlnd, many nluсаti histсlry, or mating, systе and Kiгsсhnеr 1997).W Ьаsis for suсh diffегеnсе tаtions lvould tvpiс:rll1 d е n l < l l r s t r ntthеe rе v с nч i pесts of phеnotypе thа monstеrs sееm lеss faг thr>ught. Tlriгd, and pеrl.rаpsr opеn thе Ьlасk Ь
Еuolиtion апd,Dеuеlopnlепt 221

)rosophilа mеlаtкlgаsterhаs Ьееn tionaryand dеvеlopmеntal )sarе аmongthе most famоus and (A) Hеаd of iеd froпl ilnv orgi.tnism. , at thеАпtеппttpеdiаloсus. Notе B) Hеad оf a fly thаt is hоmоzygous rismutationtrаnsformsthе qs.A rеmarkaЬlеfеirturеof this and .lyloсalizеdphеIrоtypiсеffесts.

Гfесtis a gеnеtiс manifеstаtion of Wе now know, a геsult of thе way 2003). Anothеr intеrеstingfeaturе nсе of mutant phеnotypеs to thе еs.For instanсе,somе mutations in ln anсеstralanatomy tlrаt has bееn lion yеars (Lеwis 1978)' еd hundrеds of loсi whosе mutant mеnt. Dllring thе 1990s loсi wеrе |mеotiсgеnеsof animals irl sеvеral ations of floral organ idеntity, thеir iЬеd, and somе mrrtationsproduсе on сlf Ьаsalangiospеrrns(Jaсk еt al. gеnеs produсе opmеntalrеgul:1tory :atеd.Sеvеralloсi in thе nеmatodе сhroniс phеnotvpеs (AmЬгos and )wn that affесt dеvеlopmеntal proе l l r y p е s ,а l r е r Ь о d y p r o p o r t i o n s ' :сundity,modifу сolor pattегns or lге a host of othег spесifiс phеnoсtеrizеthеsеgеnеsat thе пrolесular lins witlr rеgulatоry funсtions (Gеr.

hart irrrd Kirsсlrrrеr 1997; Wilkins 2002). Somе arе trаnsсriptiсln tllсtors' protеinsthat rеgulatе thе ехprеssion of othеr gеnеs;othеrs аrе involvеd in сommuniсation alnong сеlls (signals' reсеptors, аnd thе пrасhinеry tЬat tгаnsduсеsa pеrсеivеdsignal);e.tпdsomе геgrrlatеkеy сеllular pгoсеssеs,suсЬ .Whеn as mitosisanсl сеll dеаth. thе holrrеotiсgеnеs of thе Drr;sr4lhilа bitho' rах ald Апtеппаpеdllzсomplеxеs Wеrе isolatеd, for instanсе, thеy wеrе all found to сtlntein il sеquеnсе motif сhагасtеristiс of сеrtain DNA-Ьinding protеins.In а lristoriсal nсlсl to Batеs
2000 ). Sесond,many mutiltions rnilrriсdiffеrеrrсеsam()llgspесiеsiп nnatomy' lifе historу,or matinЕ.systеms (Raff and Kaufmarr 1983; Fitсlr |997., Cеrhart and Kiгsсhnеr 1997|' Whеthеr or not thеsе mutations also rnimiс thе gеnеtiс Ьasisfoг suсh diffегеnсеs,anсl whеthеr ()r not individuals that Ьeаr thеsеrnutationswould п'piсally sLrгvivеirr thе ц'ild (poinrs disсussеd lаter), thеy do dеmonstratеthat еvеn simplе mutations саn prodLlсеprofound сhangеs in аspесts of phеnotypе that arе есologiсirlly rеlеvant; Goldsсhmidt's hopеful monstегssееm lеss farfеtсhеd, at lеast :]t a gеnеtiс lеvеl, tЬan Wе onсе thought. Third, and pегhaps пrost gеnеrally, dеvеlopmеntal gеnеtiсs has thrсlwn opеnthе Ьlaсk Ьrlх that еvolutiсlnaryЬiolсlgistslaгgеly ignorеd for half а сеnpopulation gеl1еtiсists't]tlal]titаtivеgеnеtiсists,and turу.Utltil quitе rесеrrtl1, еvеn't()somе ехtеnt' еvсllurionarygеrrеtiсiststrеiltсd gеnеs for tlrе most part as abstraсtеntitiеs;fеw thought dееply abсlut how diffеrеnt kinds of gеnеs and mrrtlrtiоnsmight сontriЬtltе to phеnotvpiс еvсllrrtion.Ссlr-rvеrsеly, dеvеlgеnеtiсiststhought a lot aЬсlLttthеsе issltеs,Ьut гzrrеlyin an еvсllu. oprrrеntal tionar1.сontехt. Thе intеrsесtion Ьеtrvееn thеsе pеrspесtivеs has lrаd a profourrdand pсlsitivеimpасt сln Ьoth dеvеiсrpmеntalаnd еvolutiorrаrуЬiologv' Trlday, thеrе is widеsprеad intеrеst irr undегstanding r,vЬаtkinds of (Niеlsеn еt al. 200.i; Haygood еt al. gеnеsаrе suЬjесt to positivс sеlесtior-r

2007\.

222

Еuolutiсlп,апd Dеuеlopmепt

Body Plans and thе Hoх Paradoх Тhе rеunifiсation сrfdеvеlopmеntirland еvolutionary Ьiology was wеll undеr way by thе еaгly |99Оs. A foгtuitous сomЬinаtiorrсif еvеnts-thе еarliег puЬliсation of insightftrlЬooks (Gould 1977; Rаff and Кaufп-rаn19sЗ)' tесhniсal advanсеs (most notably thе infusion сlf molесular tесhniquеs into virtually еvеry faсet of Ьiologv), improvеmеnts in аnаlytiсal tсlсlls(еspесiallyphylogеnеtiс mеthods), and a sеriеs of ехсiting disсovеriеs (nrorе on thеsе latеr)_ prоpеllеd thе mеrger forwаrd. Мuсh of thе initial ехсitепrеnt rеvсllvеd around thе еvolution of animal Ьt>dyplans. As thе first dеvеloprnеntalrеgulator,vgеnеswеrе сhаrraсtеrizесl at а rnolесular lеvеl, a majoг suгprisе еmеrgеd:homologous dеvеlopmеntalrеgulator.v gеnеs arе shаrеd among organisп-rswith vеry diffеrеnt Ьody plarrs.Thе first сlеar instanсе was thе геаlizаtion tЬat liп-12, Notсh, аnd ЕGЛl , impoгtаnt rеgulatory gеnеs indеpеndеntly idеntifiеd in nеmatodеs, arthropods, and с h o г d a t е s ,a r е h o r n o l o g o u s( G r е е n w а l d 1 9 8 5 ; Y o с h е m е t а l ' 1 9 8 8 ) .B u t t h i s finding was quiсkly ovеrshadowеd Ьy thе disсovеry thаt vеrtеЬrаtеsсontain Ёlox gеnеs homоlogous to thosе in l1iеs,and thаt thеy arе сlustеrеd in thе g е n o m еi n t h е s a m е r е l а t i v еo r d е r ( A k a r т 1 9 s 9 ) . I } yt h е m i d - 1 9 9 0 st h е l i s t o f rеgulatory gеnеs sharеd among thе mlljtlr modеl systсn1sof dеvеloprnеntal Ьiologv ran to sеvегaldozеn (Raff 1996; Gегhart аnd Kirsсlrnеr 1997). Sur. vеys of othеr phyla rеvеalеd a rеmarkirЬly Ьroad phylogеnеtiс distriЬution, irrсluding Ьasal nrеtаzс)аngroups (suсh as сnidаrians :rnd сtеnсlphсlrеs)arrd anatomiсally ехotiс onеs (suсh as есЬinodеrms ilnd rnollr:sks).It Ьесamе сommonplaсе to spеak of a shаrеd ,.toсllkit''of аrrimal dеvеlopmеnt (Сarroll еtal.2001). All of this was сomplеtеly unеxpесtеd.Animals in diffеrеnt phyla arе so anatomiсaily distinсt that idеntifying hопlologoLlssrruсtufеsand dеtеrmin. ing phylogеnеtiс rеlationshipsrеmain сontеntious (NiеIsеn 2oo2). This phеnotypiс distinсtnеss hаs foгmеd onе сlf thе сеrrtrаl tlrеmеs of сomp.rrativс аnatomy for as long аs thе fiеld hаs ехistеd (HalI l992: Raff 1996\, Thе notion оf a Ьody plan is that еaсh phylum of ar-rimalshas а uniquе ссlmЬination of аnаtomiсal trаits, most of whiсlr аrе аrсhitесгural(suсlr аs Ьoсiy s1,пrmе. try), еmЬryologiсаl (suсh as tlrе gеomеtry of сеll division), or Ьoth (suсh as thе nunrЬеr
bесomе an iсon of еvolu thе knоwn gеnе fаmiliеs systеms in аnimаls datе many to tlrе uniсеllulz Kirsсhnег 1 9 L)7; Сar r t>I tal rolеs of thеsе rеgular and Аr"lbidсlpszЗ zlrе сlеl zoans. Pеrhaps е\.еnп1orеrе tеins arе ехpгеssеd in ro fеrеnt phyla (Gеrhart аl gеnеs providеd thе firs othеr orthologous rеgt tantly rеlаtес]animal ph to ovеrlook thе faсt that s i m i l a r d o m а l i n so f е x p r that thеir dеvеlopr-r-rеn f i с a t i t l no f a n i m l l s 1 D a v sirrrilaritiеsirr gеrrеехprt tеЬratеs havе Ьееn usесr tor (DеRoЬеrtis and S l o n g - е х t i n с t а n с е s t o r ss с volvеs many аssumption of thе Ьiliаtеrian аnсеs Wilkins 20021.

Okl еln.|

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Figurе 5. Тhе Hoх parad< fliеs аnd miсе dеspitеthс ; thеsе аnimаls. Тhе mosr fа еstaЬlish positiсln оf Ьodу hсlmtllog
Wrаy 2003.)

Еuоlцtiсlп аttd Dа,еl
Ьiology Was Wеll undеr llutior-rary inаtionof еvеnts-thе еаrliеr puЬ'aff aпd Kaufrrranl98З), tесhniсal olесulаr tесhniquеsinto virtually ralytiсаltools (еspесiаliyphylogеisсovеriеs(morе on thеsе latеr)i thе iпitial ехсitеmеt-ttrеvolvеd at a nlolесn., *.,. сharaсtеrizес] ologousdеvеlopmеrrtalrеgtrlatory еry diffеrеntЬody plans. Thе first I 2 ' | i , i с h . . r n d Е ( i / r 1 ,i m p o r r а n t l in nеmatodеs' arthropods, and ) 8 5 ;Y o с h е m е t a l . 1 9 8 8 ) . B u t t h i s d i s с o v е r уt h a t v с r t е l r г l t е sс о n t a i n and tЬirt thеy arе сlrrstеrеdin thе l 9 8 9 ) . B y t h е m i d - 1 9 9 0 st h е l i s t o f : modеl systеmsof dеvеloprnеntal ] е r h а r t a n d K i г s с l r n е r1 9 9 7 ) . S u r y Ьroаd phylсlgеnеtiсdistriЬution, ; с n i d а r i a n sа n d с t е n o p h o r е s )а n d :ldеrmsаnd пrollusks). It Ьесamе (Сarroll it'' of апimаl с1еvеlopnrеnt Anirтals in diffеrеnt phyla arе so nologous strLlсturеsаnd dеtеrmin. tеntiotls(Niеlsеn 2002)' This phе. 'lrе сеntгai thеnlеs of сompагаtivе .d (Hall 1992 kaff |996). Thе no. a n i m a l sh a s a t r n i q u ес o m Ь i n а t i o n rсhitесtural(suсh as Ьody symmе. ' of сеll divisitln)o , r Ьoth (suсh аs lody-pIanсol1сеptlras dееply inflr.ranimals up ttl thе prеsеnt (Gould 97). DеvеloprrrеntalЬiolоgists, foг rofouгrddiffегеnсеsin thе way in rrorphоgеnеsisсlссur ir-rеmЬryos of 7).No onе prеdiсtесlthat rnany of t to rеgulatесlеvеlopmеntthroughl dеvеlopmеntаlor еrкllutiсlnaryЬis h o w ' t h е r i r r l i I l rg е t l < l t n i(с) r g а n i and mousе: this imagе has osсl1lhilа

bесomеan iсon of еvoiutiсlnarydеvеlopmеntаlЬiоlogy (Figurе 5). Nеarly all thе knсlwn gеnе farniliеs that еnсodе transсription faсtors arrd сеll signаlirrg systеlnsin animals datе Ьirсk at lеast to thе anсеstоr o{ all Ьilatеrians, and manv to tlrе uniсеlIulаr аnсеstor of plarrts and :lnirnals (Gеrlrart and Kirsсhnеr1997.,Сarroll еt al.2001; wilkins20О2). Thе сurrеnt dеvеlopmеn. tаl rolеs of tlrеsеrеgulatory protеins in rlodеl organisшs suсh аs Drсlsopbilr,t and Аrаbidсlpsls arе сlеarly diffеrеnt from thеir original funсtions in protozoans. Реrhapsеvеn morе rеrnаrkaЬly, sonrе of thеsе сonsеrvеd rеgulаtory protеinsarе ехprеssеdin roughly sinrilar rеgions of еmЬrvos that Ьеlong to diff е r е r rpt h y l i l ( G е r h а r t a n с l K i r s с l r n e r 1 9 9 7 . ,С а r r o l l е t a l . 2 0 0 1 ) . Т h е H o x gеnеsprovidеd thе first irnd still thе most dramatiс ехamplе, Ьut many othег orthсllogor-rsrеgulаtory gеllеs shorv similar ехprеssion amсlng distantly rеlatеd animal phyla (Figurе 5). In all thе еxсitеmеnt it has Ьееn еasy to ovеrlook thе fасt thаt п.lсlstdеvеlopmеntal rеgulаtory gеnеs do zol hаvе similar dопrains сlf ехprеssion irr diffеrеnt phyla; this oЬsеrvation suggеsts thatthеir dеvеlоpmеntal гolеs havе еvolvеd сonsidеraЬly during thе divеrsi. fiсationof irnimals (Daviсison200 l; '0Иilkins2002). Thе sorrrеtimеs.striking similaritiеsin gеnе ехprеssion thаt arе sharеd Ьеtwееn arthropods and vеrtеЬrаtеshavе Ьееn usеd to rесonstruсt thе аnаtorny of thе Ьilаtеrian аnсеstor (DеRoЬеrtis and Sasai 1996; Сarroll еt al. 2001). Rесonstruсting long-ехtinсtl]nсеstorssolеly on tlrе Ьаsis of gепе-ехprеssionsimilaritiеs involvеsmany аssulnptions аnd muсh guеsswork, howеvеr, and thе anatoшy o f t h е Ь i l i а t е r i a na n с е s t o г r е m a i n s u n с е r t a i n ( Е r w i n a n d D a v i d s o n 2 О 0 2 з \)flilkins2002).

LHх2 Dlх Оtd е|nS

Hoх-t

BMP4 t:hoпlin

Ap DП

Dп hh Ap

Nkr2.2 Msх lG-Hз

Figurе5. ТЬе Hoх pаradoх. Homсllogous gеnеs pi]ttеrn tЬе еmЬrvos of fruit fliеsаnd miсе dеspitе thе plrylogеrrеtiсdistanсе аnd phеrrotypiс dispаrity сlf thesеanimаls. Thе mсlst fаmous of thеsе аrе gеnеs сlf thе Hoх ссlmplеx, whiсh еstaЬlishposition of l.odу rеgions а|ong thе аntегoPostеrior ахis. Mаnv othеr honr
224

Еuolutioп апd Dеuеlopmепt What is сlеar at this point is that thе samе Ьasiс сomplеmеnt of dеvеlopmеntal rеgulatory gеnеs' somе of whiсh arе ехprеssеd in roughly thе samе rеgions of thе еmЬryo' сan produсе a widе divеrsity of аnimal Ьody plans. Figuring out how this сlссurs is onе of thе grand сhallеngеs of еvolutionary dеvеlopmеntal Ьiology (Gегhart and Kirsсhner 1997; Сarroll еt al. 2001; Davidson 2001). A dеtailеd rеsolution of this Hoх paradoх liеs many yеars in thе futurе, Ьut сhangеs in thе organization of dеvеlopmеntаl gеnе nеtworks arе likеly to foгm an importаnt part of thе solution (Сarroll еt al. .Wrаy 2001; Wilkins 2002; еt аl. 200З). Two Ьasiс kinds of rеwiring within gеnе nеtworks havе Ьееn doсumentеd, roughly сorrеsponding to quantitativе and qualitativе сhangеs. Thе first, or quantitаtivе' сatеgory involvеs a сhangе in thе loсation or timing of ехprеssion of a rеgulatory gеnе. Suсh сhangеs сan arisе whеn a nеtwork is altеrеd upstrеam of thе gеnе of intегеst.Thе loсation or timing of thе dеvеlopmеntal proсеssеsthе gеnе сontrols will сhangе as a rеsult, potеntially altеring organismal phеnotypе. For еxamplе, thе spatial еxtеnt of Hoх gеnе еxprеssion diffеrs in ways that сorrеspond to sеgmеnt idеntity in сrustaсеans (Avеrof and Pate| 1997) and to vеrtеЬrаl anatomy in tеtrapods (Burkе еt al. 1995). Thе sесond, or qualitativе, kind of nеtwork rеwiring еntails a сhangе in whiсh dеvеlopmеntal proсеssеs arе rеgulatеd. Thеsе сhangеs сan oссur whеn a nеt. work is altеrеd dоwnstrеаm of thе gеnе of intеrеst.For instanсе,signalingvia thе rесеptor Notсh геgulаtеs spесifiсation of nеurоnal сеll fatе in insесts and spесifiсation of whitе Ьlood сеll fatе in vеrtеЬratеs (Hеitzlеr and Simpson 1991; Guidos 2002), involving two vеry diffеrеnt sеts of еffесtor gеnеs. Sim. ilarly, thе tгansсription faсtor Ьraсhyury rеgulatеsnotoсhord dеvеlopmеntin urсhordatеs and сhordatеs Ьut plays no suсh rolе in othеr phyla, whiсh laсk this struсturе; instеad, it rеgulatеs dеvеlopmеnt of thе gut and othеr struсturеs (Tесhnau and Sсholtz 2003). Dozеns of сasеs аrе now known whеrе an еvolutionary сhangе in thе еxprеssion prоfilе or downstrеаm targеts оf a rеgulatory protеin has altеrеd anatomy. Somе сasеs еnсompass сhangеs at thе sсalе of еntirе Ьody plans, suсh as thе transition from rаdial to Ьilatеral symmеtry during еarly mеtаzoan еvolution (Martindаlе еt al. 2002) and thе latеr transition Ьaсk to radial .Wray symmеtry in есhinodеrms (Lowе and 7997). Othеrs involvе modifiсations in organs' suсh as thе tгansition from fin to limЬ during thе origin of tеtrapods (ShuЬin et a|.7997), or еvolutiоnary innovations, suсh as arthro. pod wings (Avеrof and Сohеn 1997). Еvеn subtlе diffеrеnсеs in anatomy arе oftеn thе rеsult of modifiсations in gеnе nеtworks: ехamplеs inсludе diffеrеnсеs in Ьristlе pattеrns in fliеs (Stеrn 1998; Skaеr and Simpson 2000) and сolor pattеrns on Ьuttеrflywings (Brakеfiеldet a|. 1996i Brunеtti еt al. 2001; Gompеl еt al. 2005). How do сhangеs in dеvеlopmеntal gеnе nеtwoгks arisе? Thеrе arе many ways in whiсh this сan happеn-any spесifiс intеraсtion Ьetwееn maсromol. есulеs is a link in a gеnе nеtwork' and any diffеrеnсе in intеraсtions altеrs thе nеtwork. Thе two most сommon and important kinds of nеtwork сhangеs arе proЬaЬly intеraсtions Ьеtwееn protеins and intеraсtions Ьеtwееn protеins

and rеgulatoгy sеquеnсе a Ь o l i s h i n gs u с h i n t е r а с r of mutаtions, singlе Ьasе еt аl. 200J). Mаny protе nuсlеiс aсids, and small с . hаngi d r a m а t i се f f е с t sС tion or altеr affinity dr: сan сrеatе or modify a Ьi

rеgion. Сhangеs in dеvеlopmе paсt on thе history of lif and why gеnе nеtwсlrksа

Frоm ly{aсroеvoluti

Phеnotypiс сhangеs,inсlt variation within populati mеntal еvolution at thrs l aЬout thе gеnеtiс Ьasis ft wild populations (as opp thе laЬ) or aЬout what k tion in nеtwork funсtlon happеn ovеr lсlng timеsс This pauсity of inform D е v е | с l p m е n t aЬl i o l o g i s influеnсеs of gеnеtiс anс hаvе workеd largеly witl gеnt that сompаrisons 1 nisms. For thеir part' poГ a n d h а v е f t l с u s е dp r i m а r protеins, protеin struсtL rathеr than gеnе intеrасt Тhеrе arе, of сoursе' variation in thе сoding : u l a t o r y g е n е s ( е . g . ,A y a T h е s е р o p u l a t i o n - l е v е ll o f s е g r е g а t i n gv a r i а г i o n opmеntаl mесhanisrns а toriеs (е.g.' Wray and 1998), or among popu е t a l . 2 0 0 4 ) , с a n r е v е a ll сhangеs in sеlесtion. ( аЬout population gеnе opmеnt rеmlins a gleri vеlopmеntal Ьiology.

Еuolutiсlп dпd D eUе|opmепt amе bаsiс сomplеmеnt of dеvеlop'е ехprеssеdin roughly thе samе rеlе divегsit1,of аnimаl Ьody plans. е grand сhallеngеsof еvolutionary 'sсhnеr19971 Сarroll еt al. 2ОО73 this Hox pаradox liеs many yеars zation of dеvеlopmеntal gеnе nеtlart ot thе solution (Carroll еt al. e nеtworkshavе Ьееn doсumеntеd, d qualitativесhangеs.Thе first, or n thе loсation or timing of еxprеs:an arisе whеn a nеtwork is altеrеd tion or timing of thе dеvеlopmеntal a г е s u l tp ' o r е n t i e l l ya l t e r i n go r g a n еxtеnt of Hox gеnе еxprеssion difidеntityin сгLlstaсеans(Avегof and tеtrаpods(Burkе еt al. 1995). Thе wiring еntailsa сhangе in whiсh dе]sе сhangеsсan oссur whеn a nеt: intеrеst.For instanсе,signaling via Lof nеuronаlсеll fatе in insесts аnd vеrtеЬratеs(Hеitzlеr and Simpson jiffеrеnt sеts of еffесtor gеnеs. Sim:еgulatеsnоtoсhord dеvеlopmеnt in ,uсhгolе in othеr phyla, whiсh laсk )pmеnt of tlrе gut and othег struсз аn еvolutionаryсhangе in thе ехэf a геgulatoryprotеin has altеrеd s at thе sсаlе of еntirе body plans, ttеrаl symmеtry during еaгly mеtand thе latеr transition Ьaсk to radial aу 7997). othеrs ir.rvoivеmodifiсaom fin to limЬ during thе origin of ionarу innovations,suсh as аrthro:n suЬtlе diflЪrеnсеsin anatomy arе nеtworks: ехamplеs inсludе diffег)98; Skaеr and Simpson 2000) and еld еt al. 1'9961'Brunetti еt al. 2001; rе nеtwoгks arisе? Thеrе arе many :ifiс iпtеraсtionЬеtwееnmaсromoll diffеrеnсеin intеrirсtions altеrs thе :lportаntkinds of nеtwork сhangеs r s а n d i n t е r . t с r i o nbsе t w е е np г o t е i n s

and геgulilt()rysеqttеnсеsin DNA (Davidson 200 l). Crеating, rnodifvirrg'or aЬolishingsuсh intеraсtions сan
Frоm Maсroеvolution to Мiсroеvolution РhеnotypiссЬangеs,inсluding еvt>lutionaгy сhangеsin сlеvеloprrrеnt, Ьеgin аs varii.ttion within populatiсlns.Rеlаtivеly fеw str.rdiеs hаvе addrеssеddеvеlopmеntalеvolution at this miсroеvolutionary sсalе. As а геsult, wе know littlе aboLrtthе gеnеtiс Ьаsis fсlr nrodi6сatiоr-rs in dеvеlopпrеntalgеnе nеtrvorks irr wild pоpulations (as opposеd to What induсеd mutations сan aссOmplish in thеlaЬ) or aЬotlt wЬаt kinсls of еvolutiсlrrarymесl-r:rnisпls s()rtgеnеtiс \,зriаtion in nеtwork funсtion (аs opposеd tсl simply oЬsеrving tlrаt сhаn{:еsсaIr happеnovеr long tirnеsсalеs)(Purugganaгr2000; Wrаy еt al. 200З). This pauсity of informаtion dеrivеs from tw
22.t

226

Еuolutiсlпапd Dеuelopmeпt Onе unrеsolvеd Ьut rathеr Ьasiс quеstion is what kind of gеnеtiсvariаtion сontriЬutеs to еvolutionary сhangеs in dеvеlopmеnt. Thе largе-еffесt mutations Ьеlovеd Ьy dеvеlopmеntal gеnеtiсists аltеr phеnotypе in dramatiс ways, somеtimеsmimiсkins diffеrеnсеsamong spесiеs.Thеsе mutations arе proЬaЬlу not gеnеrally good mоdеls for thе gеnеtiс Ьasis of еvolutionary сhangе, in part Ьесausе thе phеnotypеs arе rarеly Wеll intеgratеd in tеrms of organismal funсtion (Budd 1999; Сarroll еt al. 2001). This doеs not mеan that mutations of iargе еffесt play no rolе in thе еvolution of dеvеlopmеnt, Ьut dеtесting thеir influеnсе is a signifiсant сhallеngе. At thе pоpulation sсalе, variants of largе еffесt arе ехpесtеd to Ье еxсееdingly rarе, and mutations of small еffесt arе еxpесtеdto prеdominatе in thе wild; еvеn at thе lеvеl of сlosе intеrspесiеs сompаrisons, multiplе mutations arе typiсally fiхеd at еaсh loсus' and dissесting out thеir individuаl сontriЬutions is ехсееdingly diffiсult (\Х/ilkins

2002). Anothеr Ьasiс quеstion is how muсh gеnеtiс variation that influеnсеs dеvеlopmеnt is prеsеnt in natural populations. Additivе gеnеtiс variation that undеriiеs a spесifiс aspестof anatomy providеs an indirесt mеasurе' sinсе it must at somе lеvеl rеprеsеnt modifiсations in dеvеlopmеnt. But Ьy itsеlf' quantitativе gеnеtiсs providеs no information aЬout what kinds of gеnеs arе rеsponsiЬlе foг trait diffегеnсеs,nor how mutаtions in thosе gеnеs altеr dе. vеlopmеntal proсеssеs.Rесеntly, thе quantitаtivеgеnеtiсsof gеnе ехprеssion has attraсtеd аttеntion аs a Way to bеgin Ьridging this gap. It has beсomе сlеаr that natural populations harЬor abundant gеnеtiсvariation that affесts gеnе ехprеssion (е.g.,olеksiak et a|.2ОО2i Roсkmаn and \Wгay20О21\Ytttkopp еt a\. 20О4). Howеvеr, еstаЬlishinga сonnесtion Ьеtwееn gеnеtiсally Ь а s е dd i f f е r е n с е si n 8 е n ее х p r е s s i o na n d о r g a n i s m a lp h е n o t y p еp o s е si t s o w n сhallеngеs.Molесular and quantitativе gеnеtiсsprсlvidе ways of tеsting this link, and сonvinсing сasеsarе Ьеginningto appеar (Brеm еt a\.2002; Shapiro et a|. 20О4; Gompеl еt al. 2005). A third Ьasiс quеstion is what еvolutionary mесhanismsopеratе on gеnеtiс variation that influеnсеs dеvеlopmеnt. Thе long-tеrm сonsеrvation оf еmЬryos that forms thе Ьasis of Baеr's laws is famous, Ьut it is unсlеar whеthеr its сausе is dеvеlopmеntal сonstraint or pеrsistеnt nеgativе or staЬilizing sеlесtion.A numЬеr of studiеshavе impliсatеd partiсular еvolutionary mесhanisms that opеratе on dеvеlopmеntal proсеssеs' inсluding rеlaхеd nеgat i v е s е l е с t i o n ( S t r i с k l е r е t a l . 2 0 0 1 ) , с h a r a с t е r d i s p l a с е m е n t( W r a у 1 9 9 6 ; G r Ь i с е t a L .| 9 9 8 ) , s е х u a l s е l е с t i o n( K o p p е t a l . 2 0 0 0 ) ' a n d d г i f t ( T r u е a n d Hаag 2001). During thе past fеw yеars dеvеlopmеntalgеnе nеtworks havе аlso Ьееnimpliсatеd in spесiation.Thе DoЬzhansky.Mullеr modеl of spесiаtionproposеs that gеnеtiс isolаtion сan arisе Ьесausе of inсompаtiЬilitiеs in intеraсtions among gеnеs at many loсi (DoЬzhanskу 79З6; Мullеr 1942|. Bесausе thеy involvе so many intеraсtions' dеvеlopmеntalgеnе nеtworks arе good сandidatеs for suсh inсompatiЬilitiеs (Johnson and Portеr 2000; !Иilkins 2002). Sеvеral loсi involvеd in геproduсtivеisolаtion havе bееn сharaсtеrizеdat thе molесular lеvеl. and most еithеr еnсodе transсriotion faсtors оr rеsidеwithin

сls-rеgulаtory rеgions (( gеnеs suggеstthat ехprе (Мiсhalak and Noсlr 20(

Есologiсal Dеvеlop

L е i g h v a n V a l е r r( 1 9 7 3 , 4 mеnt by есology.'' Thе s tеraсtions Ьеtwееn whаl disсipIinеs within Ьiolo m U s t г е - с r е J г еa f u n с г i o n in a mannег сonsistеntW a mеans to dеstination;r Ьoth aspесts of dеvеlopn far lеss аttеntion (GilЬеrt tion in thе dеvеlсlpnrеrr rOutеsto thе sаmе phеno г o U t е sа r е . r с t u . l l Iqy u i t еr tion on dеvеlopmеnt pег r еral phеnomеna. Dеvеlopmеnt in many gеnеrations аnd ссlntras dеvеlopnrеntal digrеssrс rеproduсtivе adult. In pri o Г n a г u r e I s е l е с t i o nf o r а gagе (fеаturеs that havе othеr aspесts of organlsг arе proЬaЬly truе tO solnе to Ье аdаptivе (Garstang aid in disреrsal, providе ir loсal еxtinсtion (МсЕdwс latеd to spесiеs that laсk mеnt сan aссompany thi Grbiс еt al. 1998; Bесkhа ing a partiсular adult Ьod r o u t е ( S t r a t h m a n n1 9 8 . 5 shifts in ways that еnhan lесtion has opеratеd on th Altеrnativе dеvеlopmе within а spесiеs.RhaЬditi аmplе: adults dеrivеd fro idеntiсal, Ьut undеrlyrп (Е6lix2004). (Dauеrstag a n а l t е r n а t i v еs г e g еt a k е ni t o s u г v i v еu n t i l с o n d i r i t l

L't,сllutiсllt апсl Dеt,elсlplпеttt 227 l i s w h а t k i n d o f 8 е n е t i сv а r i a t i o n lеlopmеnt.Thе largе-еffесt mutaа l t е гp h е n o г y P еi n d r l l m a t i с w a y s . lесiеs.Thеsе mutations arе proЬa'iс Ьasisof еvolutionary сhallgе' in l intеgrаtеdin tеrms of orgаnismal T h i sd о е sn o t m е а n t h а t m u г a t i o n s on of dеvеlopmеnt' Ьut dеtесting t thе pсlpulationsсalе, variаnts of rarе,and mutations of small еffесt ' е nа t t h е l е v е lo f с l o s е i n t е r s p е с i е s сally fixеd at еaсh loсus, and dis_ ; is ехсееdinglydiffiсult (Wilkins :nеtiсr,аriаtiorrthat irrfluеnсеsdе_ ns. Additivе gеnеtiс variation that lvidеs an indirесt mеаsurе' sinсе it lns in dеvеlopmеnt.But Ьy itsеlf, rion aЬout what kinds of gеnеs arе mutationsirr thosе gеnеs altеr dеrtitativg е е n е t i с so f g е n е е х p r е s s i o n r Ьridging this gap. It hаs Ьесomе ndant gеnеtiс variation that аffесts }; Roсkman and.Wray 2002; \Х/ittl a сonnесtion Ьеtwееn gеnеtiсally , r g a n i s m аpl h е n o t y p еp o s е si t s o w n эnеtiсsprovidе ways of tеsting this O appеar(Brеnrеt a|.2О02.,Shapirо s p е r а t еo n g е n е t i с r a r ym е с h a n i s m o .hе l o n g . t е r mс o n s е r v а t i o no f е m is famous' Ьut it is unсlеаг whеthег . p е r s i s t е nnt е g a r i v еo r s t а Ь i l i z i n g ;atеd partiсularеvolutionary mесhproсеssеs'inсluding rеlaхеd nеgаarасtег displzrсеmеnt{Wraу 1996; rp еt al. 2000), and drift (Truе and аl gеnеnеtworks havе also Ьееn im. '{ullеr rnodеl оf spесiirtion pгoposes o f i n с o m p а r i Ь i l i r i еisn i n r е r a с t i o n s 1936; Mullег 1942\' Bесausе thеy ntal gеnе nеtworks aге good сandin and Portеr 2000; \7ilkins 2002). ltion hаvе Ьееn сharaсtеrizеd at thе ransсriptionfaсtors or rеsidе within

сls-rеsulаtсlrv rеgions (orr and Prеsgravеs 2000), w,hilе survеys of mаny gеnеssuggеstthar ехprеssion diffеrеnсеsplay аrгсllеin геpr
ЕсоlоgiсalDevеlopmеntalЕvolutionary Biology Lеighvan Vаlеn (1973, 488) nсltеdthat ..еvolutionis the сontгol of dеvеlopmеntЬy ессllogy..'Тhе sirnpliсitу tlf this statеmеntЬеliеs tlrе divеrsity of intеraсtionsЬеtwееn what havе Ьееn studiеd trаditionally аs thrее sеpararе disсiplinеswithirr Ьiology (V/еst-ЕЬеrlrаrd2003). f)еvеlopmеrrt not orr[y mustrе-сrеatеa funсtioning adult organism еvеry gеnеration Ьut nrust do so in a rrlаnnеrсonsistеntwitlr srrrvivаl.In othеr rvords, сlеvеlopmеntis lrot just a mсansto dеstination;it is a partiсular routе to that dеstinаti
228

Еuolutioп апd Deuеlopmеnt providе additionаl ехamplеs. Both phеnomеnа аrе сommon and arе prеsеnt in phylogеnеtiсally divеrsе multiсеllular orgаnisrns;Ьoth dеn-ronstrаtеhow vаstly diffеrеnt dеvеlopшеntirlr
Prospесts

Aftеr half a сеntury of l lutionаry Ьiсllogists гесе еnmеnt. Сontemporar1 imprint of еvolutiоnary ..toolkit'' of pгotеins th: karyotеs, and сomparat dеvеlopmеntаl gеnе nеt part' hаs Ьееn influеnсе opmеntz.rl Ьiologists ha. tweеn gеnotypе and pht of singlе loсi to modеl qui1ntitativе gеnеtiсs ts funсtional anаlysis ratht vеlopmеntal and еvolut old p:rrtnеrs arе Ьасk wl porгivе rеlationship.

AсKNoWLEDGг'1l

Thаnks to Dan МсShеаaпс supрortеdЬy thе National! SpасеAdministration.

E}IвLIoGRAPHY

A Ь o u h е i f .Е . H . , N 4 .A k а m , N . H . P а t е |R' . A . R а t dеvеlopmеntalgеnеs.T A Ь o u h е i f ,Е . H . , а n d G . A . ' еvolutionof wing poly A Ь z h а l t o vA ' . ' A . P o p a d i с:' hornоlоgy of arthropo A k а m , N , I .1 9 8 9 .H o х a n dF vегtеЬrаtеs. Сell 57: 34 A l b е г с h .P . l 9 8 c . T h е l с l g i

dеvеloprnеnt аnd еvolt-

A I Ь е r с h ,P . , a n d Е . A . G a l е . trеnd:DigitаIгеduсtiо AlЬеrсh, P., S.J. Gould, G. J оlltogеnyand phylogе AlЬеrt, P. S., and D. L. Ridd dаr.rеrlikе|arуaе' Dеuеl AmЬгos, V., and H. R. Нorr Саепсlrhаbditis еlеgапs Aгthur, W. l988. AThal1, John Wilеy and Soпs.

Еt,olutioпапd DеueloDmепt 229 lеna arе сommon аnd arе pгеsеt1t rganisms;Ьoth dеmonstratе how сOnvеrgеOn сommon еnd points. oссur' adults aге litеr:prсlduсtitln еd dеvеlopmеnt in vеry diffеrеnt эd in thе prесеdingparagraph, rеlvеlopmеntaladaptаtionsgеnеrally сirсumstanсеs.Asехual rеproduс. .ndWrav 200 l ). аlld rеgеnегаtiоn а[ingmесhanisms. lst multiсеllular organisms show iponsеto thе еnviгllnmеnt thеy ехLrrdPigliuссi 1 998; !Иеst-ЕЬеrhard simply sidе еffесtsof pеrturЬation ' in mаt-tyоthеr саsеs rеsponsеs to inсludе thе growth haЬit аnd lеаf in many ;llants aгrd animаls, and in rтаny plants arrd d rеpгсlсlr'rсtitln l W е s t - Е Ь е r h a r2d0 0 З ) . liuссi1998; nvolvеsех dеtеrminаtion,rvhiсh is r d с r o с o d i l i a n s( ( i r е w sе t a l . 1 9 9 4 ) ( G о d w i nе t a l . 2 0 0 З ) . llilstiсity ц.lrеrеdisсгеtе moгphs dеhas Ьееn pаrtiсularlу Polyphеr"rism and aphids havе sеasсlnalmorphs, пrtlгphsdеpеndingon waonr,vingеd , thе soсial insесtsdеvеlсlpinto dis/еst-ЕЬеrhаrd 2003), In polyphеnism roге distinсt phеnotypes thаt аrе аt rus and in somе сasеs a good dеal lеntal Ьi1sеsof plrеrrotypiсplastiсity nd Pigliuссi 1998; \Wеst-ЕЬеrhard агound thе quеstiоrlswhеrlrеr thеrе thег plastiсity is а prodr-rсtor Ьyr l i с t i n gа n d P i g l i u с с i 1 9 9 8 ) . T h е е х еnvironmеntalсonditions, аnd this ansduсirlgехtеrnаlсuеs irrt
Prospесts Aftеr half a сеntury of largеly ignoring еасh othеr, dеvеlopmеntal and еvolutionaryЬiologists rесеntly еntеrеd a phasе of prоfound rесiproсal еnlightеnmеnt. Сontеmporаry dеvеlopmеntal Ьiology Ьеaгs an unmistakaЬlе imprint of еvolr-rtionary сonсеpts:phylogеnеtiс mеthods rеvеаlеd thе sharеd ..toolkit'' protеins of that rеgulatе dеvеlopmеntal proсеssеsthroughout еukaryotеs'and сomparativе mеthods arе now routinеly usеd to сharасtеrizе dеvеlopmеntalgеnе nеtwоrks. Сontепrp
AсKNoWLEDGMЕNтs Thanksto Dаn MсShеaand Мiсhaеl Rusеfor insightfulсommеnts'My rеsеirrсh is supportеd by thе NatioпalSсiеIrсе Fоurrdаtion аnd thе NаtioпalАегonаutiсsаnd SpaсеAdrninistration.

B|вLIoGRAPHY .W. Abоuhеif, Е. L{.,M. Akam, J. Diсkinsоn'P. !и. Н. Holland,А. N{еyеr, N. H. Patеl,R. A. Raff, V. L. Roth, and G. A. Wrav. |997. H
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Еuolutioп апd Dеuekrymеnt |997. Тhе Оrigiп of Апimаl Bodу Plапs. СamЬridgе: СamЬridgе Univеrsity Prеss. Avеrоf, М.' аrrd S. М' Сohеn. 1997. Еvolutionаrу оrigir-rof insесtwings from anсеstrаl gills. Nаturе З85: 627_63О. Avеrof, N{., аnd N. H. Patеl. l997. Сrr'rstaсеаnappеrrdagееvolution assoсiаtеdwith сhangеs in Hoх gеnе ехprеssion.Nаturе 388: 682-686. Ayala, F. J.' and D. L. Нartl. 1993. Мolесulаr drift oi thе bridе of sеuепlеss(boss) gеnе irr Drosophilа. Мolесulаr Biologу апd Еuolutklп 10: 1030-1 040. Bаеr, K. Е. von. 1'828. 0hеr Еntн'iсkеlипgs1еsсhiсhtе tlеr Thiеrе: Bесlbасhtuпg uпd Rе|lех i tlп' Koni gsЬеrg: GеЬгirdеr Borntr:igеr. Bаtеson, !и. l894. МаteriаIs for thе Stиdу of Vаriаtitlп Тrеаtеd шith Еspeсiаl Rеgаrd tпаr>, Sупtbеsis: Pеrspесtit,еson tbе LIпifiсаtiсlпof Biologу, 1|2-122. СamЬridgе, NlA: Наrvard Univегsit,v Prеss. Сrе''vs' D., J. М. Bеrgеron'J. .}.Bull, D. Florеs, A. Tousignаnt,J. K. Skiрpег' аnd T, Wibbеls. 1994. Tеmpеrilturе-dеpеndеnt sеx dсtеrmination in rеptilеs: Proхimatе mесhanisms,ultimatе outсomеs' and ргaсtiсal aрpliсаtions. D еuеlopmепtаl G епеtiсs 15 : 297_312,

D a г w i n , С . 1 8 5 4 .А М , Sеssile Сirri1lеdеs), 1859. Оп tЬе ( D a v i d s о n , Е . H . 2 0 L )I . (

Sаn Diеgo: Aсadеп dе Quеiгtlz' K. l984. Тl аnd its rеlеvanсе tс D е R o Ь е r t i s ' F i .M . , а n d in Bilatеriir. Nаturе D i с k i n s о n .w ' J . l 9 8 8 . insights аnd inrpliс D o Ь z h a r r s k v ,Т . t 9 З 6 . s in Drоыlphilа psеи Еrwin, D. H., аnd Е. H. D е u е l t l p m с п !| 2 9 Еvаns,J. D., and D. Е. \ dеtеrmination. Gez Е ё I i х ,М . А . 2 0 0 4 ' A l t е r rhaЬditid nеmаtodе Fёliх' lr4. A., аnd P. W. l prесursor сеlls in tц F i s h е r ,R . А . \ 9 З О . T h е Prеss. Fitсh' D. H. |\,7997.Еу rеlаtеd to Саепrlrhа Garstang, W. J. 1922.7 Ьiogеnеtiс |aw. Jtllt 81-101. 1928. Тhе morp thе Chordаtа. Qиar 1929. Thе origir Aduаnсеmсn! of Sсi Gеrhart, J., and М. Kirsс Сеllulаr lltJ Dа'еl.' Еu
Еuolt,ttioп апd Dеuеlopmепt . СamЬridgе:СamЬridgе Univеrsity .у origin сlf insесt wings from еvolution аssoсiаtеdwith Lppеndаgе 8:682-686. гift of thе bridе of sеueпIess(boss) Еuolutioп 10: 1030-1040. liсhtе der Тhiеrе: Bеobасhtuпg uпd

г'

riаtiоп Тrеаtеd ulith Еspесiаl ,eсlсs.Nеw Yoгk: Мaсmillan. 4 Dеfепсе. СапrЬridgе: СamЬridgе )03.Loсаlizаtiсinof RNAs in ooсytеs рing frog, diffеrs from XепopL|s 11

)хford: СIarеrldortPrеss. z. London: oxford Ur.rivеrsityPrеss. I rеgenеratiotland fission in алnеlids: сIаssgеnе ехprеssion. DеuеIoРпeпt .!(ijngаardеn, A. Мontеiro, , P. J. pmеnt' рlastiсityand еvolution of 6-242. yak. 2002. Gеnеtiс dissесtion of .. Scieпсе296: 7 52-7 5 5. rеgulаtion for highеr сеlls: A thеory. irеnсlr, P' M. Bгаkеfiеld, arnd vеrsifiсаtionof Ьuttеrfly еyеspot сolor 'еrninggеt.rеs drivе moгpholоgiсal -зз2. nеntal pаttеrtlsаnd thе idеntifiсаtion 178:666-668. С. TaЬin. 1995. Hoх gеnеs аnd thе D еuеlopmеп,t121 333_346. [. Riсhmond, еds. 1993. Thе 8, 1860' СamЬridgе:СamЬridgе 'Ьее.2001. From DNА trl Diuеrsitу: |пimаl Dеsigп. Мaldеп, МA: Blaсkwеll .,\on thе еvоlurionсlf gеnеriс 244. .y synthеsisand thе biogеnеtiс lilw. In lutioпаrу Sупthеsis:Pеrspесtiuеs on r Ь г i d g еM ' А: Hаrvагd Univеrsity , A. Тousigпаnt,.}.K. Skippеr, аnd t sех dеtеrmination in rеptilеs: ,s,and рraсtiсаl аppliсations.

Darwin, с. 1854. А Мoп,ogrаph of thе Sub-clаss Сirripеdiа: Thе BаIаnidаe (or SеssilеСirripеdеs)' thе Vеrruсidае, фс. Londсln: liаy Soсiеtv. , |859. oп the Оrigiп of Sуlесiеs.London: John йurray. Davidson, Е. H. 2001. Gепсlmiс Rеgulаtсlrу Sуstеtпs: Deuеklpmеnt апсl Еuсllution. Sаn Diеgо: Aсadеmiс Pгеss. dе Quеiroz' K. 1984. Thе ontogеnеtiс mеthоd for dеtеrmining сharaсtег and its rеlеvаnсе to_рhylogеnеtiсsystеmаtics. Sу5уе?nаil,2.,olс,gу рoiаrity З4:280-299. DеRoЬеrtis,Е. M'' and Y. Sаsai. 1g96. ^сопlmon рlаn for do.,ouеit."l pattеrning in Bilatеria.Nаturе.380: 37-40. Diсkinson,!и. 'I. 19s8. On thе arсhitесturеof rеgulatory systеms:Еvolutionary insightsand impliсations. BloЕssays 8: 204-208. _ . DоЬzhaпsky,T. 19З6. Studiеs on hyЬrid stеrility.II. Loсаlization of stеrility faсtors in Drosсlphilа psеudсюbsсurа ЬуЬrid's.Сеп,etiсs 21: 1 l3-135. _ Еrwiп, D. Н., аnd Е. Н. Dаvidsоn.2002. Thе lаst сommon Ьilatеriап аnсеsror. D еuеlop m епt 129 : З027*ЗО 32". Еvans,J. D., and D. Е. Whееlеr.2oo1. Ехprеssion profilеs duгing honеyЬеесastе dеtеrmination.Gеnomе Biologу z. ooot_oоoь. Fёlix' М. А,2004. Altеrnаtivе morphs and plastiсity of vulvаl dеvеlopmеntin a rhaЬditid nеmatode spесiеs. Deuеlopm)пt (jепes апd Еuсllutioп 21,4: 55-6З. Fёliх,М. A., arrd P. IJИ.StеrnЬеrg, 1998. A gonad.сlеriv.а,u.uiuui.ig*l fo. u,,luаl prесursor сеlls in two nеmatodе spесiеs. Сttrreпt Biologу 26: 28;-290. Fishеr,R. A. 193O. Тhе ()епеtiсаl Thiorу of Nаturаl Sеlесtiott. oxford: Сlаrendоn Prеss. Fitсh.D. H. ^. \997. Еvolution of malе tail dеvеlopmеnt in rhabditid nеmatodеs rеlatеd to Саеnorhаbditis еlеgаns. Sуstеmаtiс Biologу 46:145-179. Gаrstang,w. l. 1922-.Thе thеory of гесаpitulation: A сritiсal rеstatеmеntof thе biogеnеtiс|aw. JсlиrпаIof the Liппeiп Soсietуof l-сlпdLlпi2";й) 35. 81-101. 1928. Thе morpholоgy ofthе Tuпiсаtа, and its Ьеaring on thе phylogеny of thе Сhordаtа. Quаrtеrlу Jсlurnаl rlf Мicrсlsсopу Sсiеncе вi, toз.Ьз. _--l: 1929.Thе оrigin and еvolutiоn of lаrvаl iorms. British Аssoсiаtioп for thе Аduапcеmепt of Sсiепсе 1929 : 77-98' Gеrhart,J., and М. Kirsсhnеr. 1997. Сеlls, Еmbrуos, апd Еuolution: Toшаrd а Сellцlаr апd Dеuеlopmепtаl (Jпdеrstаndiпg of Pheпotуpl, io,,i,otion-ond Еuolutiсlпаrу Adаptаbi|i/y. Мaldеn' МA: йaсkwеll Sсiеnсе. . GiЬson, G.' and I. Dwсlrkin. 2004. Unсоvеring сгyptiс gеnеtiс variаtion. Nаturе Ret,iеtl,sGеnеtics 5: 681-690. Gilbеrt, s. F. 2001. Есologiсаl dеvеloprnеntal Ьiolсlgy: Dеvеlopmеnrаl Ьiolсlgy mееts thе rеal world. Dеt,еlopnlеntdl Biologу 23З: 1-12. . 2006. DеuеlopmепtаIBiсiogу,8th еd' Sundеrland, МA: Sinauеr Assсlсtaгеs. ' GilЬеrt, S. F.' aпd A. М. Raunio . tiiт. Еmbr.lolog1,: Сoпstruсtiпg thе Оrgаtlism. Sundеrland,МA: Sinаuеr Assoсiatеs. Godwin,J., J. A. LuсkеnЬaсh, and R. Borski. 2003. Есology mееts еndoсrinology: J. Еnvironпrеntal sех detеrminatiсln in frsЬеs'Еuсiиtioп й,Dеuelopi."i s.4О49. Gоldsсhmidt' R. 1940. Thе Маtеriаl Bаsis
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S h а p i г t l '] \ l . D . , М . Е . ] \ l D. Sсhlutеr, and D. l еvolutionаry pеlviс r ShuЬin, N., С. TaЬin, аnt animаl limЬs. Na,иrr Skаеr, N., and P. Simpso Drosopbilа mеlапоg с:ls-rеgulatorysеquе Biсllogу 221 148-16 S t е r n ,D . L . 1 9 9 8 . A r o l е Drosophilа spесiеs.l ?000. Pеrspесtrv vaгiаtion. Еurllutioп S t r а t h m а n n ,R . R . I 9 8 5 . е v o l u t i o n i n m . r r l r l еi З.39_361 . Striсklег, A. G., Y. Yamar Par6 ехprеssion aссо Dеuеlopmепt Gепеs , S w а ] I а .B . J . ' a n d W . R . J е сhoгdаtе fеaturеs iп а Tесlrnau, U', and C. B. Sс lttеsodеrm.l пtсrпаt it Тгuе, J. R.' and Е. S. Haа1 еvсllutiоnаry trajесto van Vаlеn, L. 1973. Fеsts Via, S., R. Gomulkiеwiсz Р. H. V. Тiеndеrеn. l сontrovеrsy. Тrепds tl .Waddirrgton' С. H' 1957. of T h еorеtiсаl B irllo g' !Иagnеr, G. P.' and J. A. с thе hornоIogy of thе с Асаdеlтtу of Sсienсеs W:1r1$,R. L., A. Stес, J. Hс during maizе domеsti Wеst-ЕЬеrhard,М. J. 200. Univеrsity Prеss. .Whitmirп, С. О.1919. ort In stitrrtе. Wilkins, А, S. 199З. Gепсt 2ОО2. The Еt'оlнti Assoсiаtеs. Williarns, N. ,\., and P. W. сhordatеs. Brаiп Bеhа IWilson, A. С. 1975. Еvolu 7:117-134. .W. Wiпrsatt, С. 1986. Dеt. i r r n a t с - a с q u i r с Jdi s t i n l 85_208. Dordrесhr, Wittkopp, P.J.' B. K. Haеr and trапs gеnе rеgulat .Wrаy, G. ^' 1996. Pаrallеl Birllogу*45 З08-З22.

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Shаpiro,М. D., М. Е' Marks' С. L. PеiсЬel,B. K' Blaсkmаn, K. S. Nегеng, B. Jоnsson, D. Sсhlutеr,arrd D. М. Кingslеv. 2004. Gеnеtiс and dеvеIopmеntаlЬаsis оf еvolutionzrrypсlviс rеduсtiсln in thrееspinе stiсklеЬaсks . NLlturе 428: 7 1'7-72З. ShuЬin'N., С. TaЬin, аnd S. B. Сarroll. l997. Fossils' gеnеsand thе еvolution of animаl limЬs. Nаturе 388: 639_648. Skаеr'N., and P. Simpson. 2000. Gеnеtiс analysis of Ьristlе loss in hyЬrids Ьеtwееn Drosophilа mеlапogаster and D. simиIапs providеs еvidеnсе for divеrgепсе of сls-rеgulаtory sеquеnсеs in the асhаеtе-sсutе gеne сomplех. I)еt,elopmепtаl Biologу 221: 148_|67, Stеrn,D. L-. 1998. A гolе оf Ultrаbithorах in rтoгplrologiсal difftrеnсе Ьеtwееn Drosrlphilа spесiеs.Nаturе 396: 46З-466. 2000. Pеrsресtivе:Еvolutiona11,dеvеlopmеntalЬiologl' аnd thе рroblеm of variation. Еuolutioп 54: 1О79-1091, Strathmann,R. R. 1985. Fееding and nonfееdir-rg larval dеvеlopmеntаnd lifе history еvolution in mаrinе invеrtеЬratеs.Апппаl Reuiеtu of Есologу, (t Sуstemаtiсs \6: зЗ9-361. Striсklеr,A. G., Y. Yalпlаmoto,and W. R. Jеffетy.2001. Еarly and lаtе сhangеs in Paя6 ехprеssiOnассolnpany еyе dеgеnеrаtiorrduring саvеfisЬdеvеlopmеnt. Dеuelopnrctt Gепеs апd Еuolutiс.lll2|1: 138-144' Swalla,B. J., and W. R. Jеffеrv. 1996. Rеquirеmеnt of the Мапх gеnе fог еxprеssion of сhordаtеfеaturеsirr a tаillеssasсidiаn |arуa' Sсiепсe274: 12О5_12О8. Tесhnаu,U., and С. B. Sсhсlltz.2003. origin and еvolution of еndodеrm and mеsоdеrm. lntcrпаtklпаl Jourпаl of Dеuеlopmепtаl Biologу 47: 53Т_5З9. Truе'J. R., аnd Е. S' Наag.200]. Dеvеloprnеntalsystеmsdrift and flеxibility in еvolutionаrytrajесtoriеs.Еuolution Ф DеuеloPmепt З: 7О9-119. van Vаlеn, L. 197з. FеstsсЬrift.Sсiеnсе 180: 488. Via, S., R. Gonrulkiеwiсz, G. dе Jorrg. S. М. Sсhеinеr, С. D. Sсhliсhting, and P' H. V. Тiеndеrеn. 199.5.Adaptivе phеnotypiс plastiсit1':Сonsеnsus and .|О: сontrovеrsy. Тrепds in Есologу апd Еuolutiсln 21'2_2|7. !Иaddington' С. H, 1957. Thе Strаtegу oi thе Gепes: А Disсussitlп of Some Аspесts of Thеorеtiсаl Biologу, London: Allеrr and Unwin. .!Иagnеr' G . P . ' а n d J . A . G a u t h i е r . 1 9 9 9 . | , 2 . З = 2 , З , 4 zA s o l u t i o l rт o t h е p r o Ь l е m o f thе homology of thе digits in thе аviarr Ьand. Proсееdiпgs o|.thе Nаtioпаl Асаdеmу of SсiепсеsUSA 96: 51 1 1-.51l6. W a n g ,R . L . , A . S t е с , J . H . y ' L . L u k е n s , а n d J . D о е Ь l е у ' | 9 9 9 . T h е l i m i t s o f s е l е с t i o n during mlizе domеstiсatiоn. Nаtнrе З98: 2З6-2З9. Wеst.ЕЬеrhard'М. J. 2003. DеuеlopmепtаI Plаstiсitу апd Еuolutiсlп. Oхford: oxford Univеrsity Prеss. .!Иhitman, C. o. 1919. Оrthсlgепеtiс Еuolцtiсlп iп Рigеons..!7ashington,DС: Сarnеgiе Institutе. Wilkins, A. s. 199'j. Gепеtiс Aпаlуsis of Апiпlаl Dеuеlo1lmепt.Nеw York: \filеy-Liss. 20О2..Тhе Еuollttioп of Dеuеlopпlепtаl Pаthшауs. Sundеrland, МA: Sinauеr Assoсiаtеs. !Иilliams,N. A.. :rnd P. w. Н. Hollаnd. l998. Мolесular еvolution of thе brain оf сhordаtеs.Brаiп Bеbаuior апd Еуolцtiсln 52:177_185. .lfilson, ^. С. 197 5. Еvolutionaгy importanсе of gеnе rеgulatiorr. Stаdlеr Sуmposi um 7:117-134. Wimsatt,\r. с. 1986. Dеvеlopmеntalсotrstraints'gеnеrativееntrеnсhmеnt'and thе innаtе-aсquirt.с]с]istinсtion.ln P. Bесhtеl' ed., lпtеgrаtiпg Sсiепtifiс Disсipliпеs, 185-208. Dordrесht, Thе Nеthеrlаnds:Martinus Nijhoff. Wittkoрр' Р.J.' B. K. Hаеrum, аnd A. G. Clаrk. 2004. Еvolutiorrаryсhangеs in сls andtrаtls gеnе rеgulation.Nаturе 430: 85-88. Vray, G. ^. 1996. Parаllеl еvolution of non-fееdinglarvае in есhinoids.Sуstеmаtic B i о l o g у4 5 : . l 0 8 _ З 2 2 '

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Еuolиtiсlп аnd DеuеklDlneпt 2003. Trаnsсriptional rеgulation and thе еvolution of dеvеlopmеnt. lпtеrпаtioпаl .|ournаl of Dеuеlopmепtаl Biolсlgу 47: 675_684. .Wray, G. A., аnd A. Е. Bеly. 1994.The еvolution of есhinodеrm dеvеlopmеntis drivеn Ьy sеvеral distinсt {aсtors.Dеuеlopmеnt 120, Supplеmentz97_106. Wray, G. A., М. W. Hahn, Е. Abouhеif, J' P. Bаlhoff' M. Pizеr' М. V. Roсkman, аnd L. A. Romano. 2003. Thе еvolution of trаnsсriptionalrеgulation in еukaryotеs. МolесиIаr Biologу апd Еuolиtioп 2О: |З77-"l'41'9. \Х/ray,G. A., and С. Lowе. 2000. Dеvеlopmеntal rеgulatory gеnеs and есhinodегm J. еvolution. Sуstemаtiс Biologу 49: 28-51'' Wray, G' A., and R. A. Raff. 1990. Novеl origins of linеagеfoundеr сеlls in thе dirесt dеvеloping sеa uтcЬiл Hеlioсidаris erуtbrogrаmmd. DеuеIopmeпtаI Biologу 1'41:41'-54. Yang, A. S. 2001. -N4odularity'еvоlvaЬility,and аdaptivе radiations:A сomparisоn of thе hеmi- and holomеtaЬolous insесts.Еuolutioп (t Dеuеlopmепt 3: 59_72. Yосhеm, J., K..Wеston, and I. Grееnwald. 1988. Thе Саепсlrhаbditisеlеgапsliп-12 gеnе еnсodеs а trаnsmеmЬrаnе protеit-twith ovеrall similarity to Drosophilа Notch. Nаturе .]35: 547_550.

SoсialBе Soсiobio

Dаniel l. Rьl

N4ost animals livе solitar1 individuals foragе, movе highly soсial animals our long.tеrm rеlationships a spесiеs livе in groups anс want to know why somе I 'Wе want to know why сo tivе and сompеtitivе tеndt many soсiеtiеs. \й/еalso w uals and thе sеxеs dеvеlo not. Answеrs to thеsеquе to animals to lеarn aЬout . answеring thеsе аnd othеr Ьy problеms. Bеhavior, lik thе fеar that what animals to shy away from asking aЬout thе adaptivе valuе с

Foundations in Natu

U n d е r s г a n d i n gw h y s p е с i е q u i r е s d r а w i n g i d е а sf r o m half сеntury thеsе idеas, t bееn wovеn into a сohеrе iorists had to сlarify hоw t thе mundаnе to thе fasсrn to ask' ..Why arе thеy ЬеЬ (196з) proposеd that thеr tions. Thrее wеrе standard

] еvolutiOnоf devеlopmеnt. bg1'47:675-684. r o i е с h i n o d е r md е v е l o p m е n ti s епt |20, Supplеmеnt:97_106. l h o f f ,M . P i z е r .M . V . R o с k m а n ' rеgulаtion rn transсriptionа1 п 20 1З77-I4I9. rтalгеgulatorygеnеs and есhinodеrm Lsof linеagеfoundеr сеlls in thе уth r ogrаmm а. D еuеlсlpment а I adaptivеradiations:A сompartson uolutitlп Ф Dеuеlсlpmeпt З: 59_72' . Тhе Саепrlrh аbditis е!еgапs liп- 12 h ovеrаll similarity to Drсlsopbilа

Soсial Bеhaviorand Soсiobiology Dаniеl l. Rubenstein

Most аnimals livе solitary livеs' Apart from сoming togеthеr to matе' most individuаls foragе, movе aЬout, anсl аvoid prеdatoгs on thеir own. Yеt as highly soсial animals oursеlvеs, Wе aге fasсinatеd by spесiеs that dеvеlop .Wе long.tеrm rеiationships and livе soсial livеs. want to know why suсh .!Иe groups spесiеslivе in and why thе groups takе thе form that thеy do. want to know why somе groups pеrsist, whеrеas Othеrs arе morе transitory. Wе want to know why сoopеrаtion сomеs in many typеs and why сoopеrativе and сompеtitivе tеndеrrсiеsshаpе most rеlationshipsаnd thus сoехist in mаny soсiеtiеs.\Wеalso want to know why partiсular rolеs Ьеtwееn individuals and thе sехеs dеvеlop and why somе appеar univеrsаl, whilе othеrs do not. Answеrs to thеsе quеstions сontinuе to еmегЕ]е'Ьut sinсе wе oftеn look to animalsto lеаrn aЬout oursеlvеs'thе аЬility to foсus thе lens of sсiеnсеon answегingthеsеand other quеstionsabout human soсiality has Ьееn сloudеd Ьy proЬlеms.Bеhavior, likе all othег fеaturеsof thе phеnotypе,еvolvеs, and thеfеar that what аnimals do, humans must also do has oftеn сausеd pеoplе to shy away from asking' or at timеs еvеn bеing allowеd to ask' quеstions aboutthе adaptivе valuе of soсial bеhavior.

Foundationsin Natural History Undеrstandingwhy spесiеs ехhibit thе pattеrns of soсial Ьеhavior thеy do rеquiгеsdrawing idеas from еvolution, есology, and еthology. During thе past half сеntury thesе idеas, еaсh spun fгom diffеrеnt modеS of thought, havе bееnwovеn into а сohеrеnt Ьut lеngthеningсonсеptual сloth. Fiгst, Ьеhav_ ioristshad to сlаrify how thеy еxplainеd thе appеаranсеof a Ьеhavior. From thеmundanе to thе fasсinating' thе Ьеhavior of animals induсеs thе сurious ...!Иhyarе to ask, thеy Ьеhaving in this way?'' In а sеminal artiсlе TinЬеrgеn (1963)proposеd that thеrе wеrе four ways of answеring thеsе ..why'' qrrеstions.Thrее wеrе stаndard farе that foсusеdon issuеsсlf immеdizrtесausation,

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Soсiаl Behаuiorапd Soсiobioklgу ontogеnеtiс dеvеlopmеnt' аnd еvolutionary history. What hе addеd was a fourth that foсused on unravеling a Ьеhavior's funсtion Ьy idеntifying how it augmеntеd an aсtor's survival or rеproduсtivе valuе. This еmphasis on еxplaining Ьеhavioг in tеrms of sеlесtivеЬеnеfitsto individuals hеlpеd movе ехplаnations of soсial funсtions away from what is good for groups to what is good for thе individuals that сomposе thоsе groups (\й/illiams1966). TinЬеrgеn's insights idеntifiеda сonfusion that oftеn pеrvadеsthе study of Ьеhavior, namеly, that therе arе Ьroadly two typеs of ехplanations:proхimatе and ul. timatе. Idеntifying triggеrs,or rеlеasеrs,of a Ьеhavior or thе timing of its ap. pеaranсе during ontogеny yiеlds proximatе ехplanations Ьесausеthеy foсus on thе maсhinеry within animаls thаt gеnеratеs thе Ьеhavior. Idеntifying how a bеhavior altеrs an individual's fitnеss or thе way in whiсh historiсal antесеdеntsdеtеrminе what matеrial сonstitutеs thе rеpеrtoirе of a spесiеs yiеlds ultimatе еxplanations;thеy foсus on thе еvolutionary roots and сonsеquеnсеs of Ьеhavior. of сoursе' this diсhotomy is Ьlurry sinсе mесhanistiс pattеrns havе funсtional сonsеquеnсеs,and as a rеsult thеy too еvolvе. But for thе most part' kееping thе lеvеl of ехplanationsсlеar whеn aссounting for why animals Ьеhavеthе way thеy do was a major Ьrеаkthrough.If this praсtiсе had Ьееn aссеptеdwidеly, many of thе argumеntsthat havе plaguеd thе study of soсial Ьеhaviоr, еspесially as it rеlatеs to humans, сould havе Ьееn avoidеd. Sесond, sеarсhingfor a Ьеhavior'sfunсtion, or adaptivе valuе, nесеssitatеs assеssingits rеlationship to thе еnvironmеnt.Long Ьеforе Darwin, Ьiologists .W.hat intеrprеtеd morphologiсal traits in rеlation to thе еnvironmеnt. Dar. win did Was dеmonstratеthat suсh adaptationsсould arisе without a сrеator' thus сompеlling еarly naturalists to sеarсh for еnvironmеntal prеssurеs thаt сould servе as sеlесtivе,or shaping' аgеnts.onе of thе еarliеstand most сompеlling studiеs that dеmonstratеdthat the adaptivе valuе of еntirе soсial systеms сould Ье еxplainеd Ьy diffеrеnсеs in есology Was Сrook's (1964a, 1964ь) study of wеavеrЬirds.By еxamining thе foraging, nеsting' grouping, and mating Ьеhavior of ovеr 100 spесiеs of Afriсan Wеavеrs that oссupiеd haЬitats ranging from tropiсal forеststo grasslandsand sаvannas,Сrook was aЬlе to dеmonstratеthat есologiсal faсtors assoсiatеdwith thе distriЬution of food and prеdators Wеrе rеsponsiЬlеfor thе Ьroad soсial diffеrеnсеsthat thе spесiеsеxhiЬitеd. Thosе spесiеsthat livеd in forеststеndеd to Ье solitary' insесtivorous,tеrritorial, draЬly сolorеd' and monogamous. Crook arguеd that thеsе traits сovariеd bесausе insесts wеrе hard to find. Sinсе fееding young rеquirеd frеquеnt visits to thе nеst Ьy fathеrs and mothеrs, monogamy and pairwise dеfеnse of arеas whеrе insесts would rеаppеar lеd to monogamy and tеrritoriality. Сrook also suggеstеdthat Ьuilding сryptiс nеstswithin tеrritoriеs and thе еvolution of draЬ сoloration would rеduсе prеdation. Сonvеrsely, thosе spесiеs that livеd in savannas and othеr opеn landsсapеs tеndеd to Ье soсial, еаtеrsof sееds'сolonial, and polygynous' with malеs сovеrеd in Ьrightly сolorеd fеathеrs.Sinсе sееds oftеn arе сlumpеd, Crook Ьеliеvеd that Ьеnеfitsаssoсiatеdwith groups Ьеing aЬlе to sеarсh foг sееdsovеr widе arеas lеd to thе еvolution of soсiality and that соlсlniality еmеrgеd

bесausе safе nеst sitеs. safеst trееs. \With oppс polygyny and Ьright m еtiеs of many othеr gro parativе lеns (Laсk 196 mеthods of сatеgorizin among spесiеs havе Ье сomparativе mеthod t among Ьеhavioral out Ьroad-Ьrush undеrstaп yond what сritiсs (е.g gain a mесhanistiс unс why partiсular soсial r сirсumstanсеs was nее е x p l a i n i n d i v i d u а [d е с i

Еmеrging Thеorеti

Two diffеrеnt thеoriеs ц ogists. Why animals sh thеmsеlvеs,is a quеstio was puzzlеd aЬout wh; through oссurrеd whеп Until thе mid-1960s thс Еdwаrds (7962) сЬam mеans of rеgulating po opеratеd. Williams (19

сial intеraсtions augmе Hеnсе sеlесtion aсtеd о individuals, thеn aссou straЬly hеlp rесipiеnts proЬlеm. Hamilton's in only dirесtly through о rеlativеs. Thе сomЬinat clusiue fitпess and provl Еvеn stеrilе сasts of ins produсtion of rеlativеs fiсiеnt,'' and Hamilton сrеation of tЬe kiпship dеrivеd Ьy a rеlativе m rеlativе dеvalued Ьy thс for undеrstanding thе and has Ьееn supportеd That Ьеnеfits and сot for thе dеvеlopmеnt of .

Soсiаl BeЬаuior апd Soсio|эiologу 2з9 .!7hat hе addеd was a r history. lr's funсtion Ьy idеntifying how it tivе valuе. This еmphasls on еxits to individuаlshеlpеd lnovе еХhat is good for grouPs to what is r groups(Williams 1966). TinЬегэn pеrv.rdеsthе study of Ьеhavioг' proхimatе and ul[ ехplаrrаtitlns: а Ьеhаvioror thе timing of its zlp_ э ехplanationsЬесausеthеy foсus nеratеsthе Ьеhavior. Idеntifying ss or thе way in whiсh historiсal titutеsthе rеpеrtoirе of a spесiеs t h е е r ' o l u t i o n e r ryo o t s a n d с o n s е _ ltomу is Ьlurry sinсе mесhanistiс d as a rеsult thеу too еvolvе. But . n а t i o n сs l е а rw h е n а с с o u n t i n gf o r If this praсLmajor Ьrеakthror'rgh. э argumеntsthat havе plaguеd thе :latеsto humans, сould havе Ьееn i o n ' o r a d a p t i v еv а l u е ,n е с е s s i t а t е s nt. Long ЬеforеDаrwin, Ьiologists ln to thе еnvironmеnt. What Darrionsсould aгisеwithout a сrеator' r for еnvironmеntаlprеssurеs that . onе of thе еarliеstand most сomadaptivеvaluе of еlltirе soсial sysin есologуwas Crook's (1964a, n g t h е f o r а g i n В ,l 1 е s t i n gg, r o u p i n g , of AIriсаn wеavеrs that oссupiеd гasslandsand savannas,Сrook was with thе distribution of i аssсlсiаtеd hе Ьroad soсial diffеrеnсеsth.1tthе in forеststеndеd to bе solitary, ind monogamous.Сrook arguеd thаt : hard to find. Sinсе fееding young :hеrsilnd mothеrs, monogamy аnd would rеappеar lеd to monogamy LatЬulldingсryptiс nеsts within tеrtion woLlld rеduсе pгеdation. Сonannаs and othеr opеn larrdsсapеs al, and polygynous,with malеs соv. ееds oftеn arе сlumpеd, Сrook bеs Ьеingablе to sеarсlrfor sееds ovеr еmеrgеd ality and that с
Ьесausеsafе nеst sitеs wеrе rarе, induсing mаny pairs to nеst togеthеr in thе safеsttrееs. !Иith opportunities for сuсkoldry prеvalеnt, Сrook argued that polygynyand Ьright malе сoloration wеrе also favorеd. Over thе yеars soсiеtiеsof many othеr groups of animals havе bееn analуzеd by usе of this сom. p a r а t i v еl е n s ( L a с k | 9 6 8 i l a r n a n 1 9 7 4 i K r u u k 1 9 7 5 ; F r i с k е 1 9 7 5 ) .A l t h o u g h mеthods of сatеgorizing Ьеhavior and сlassifying еvolutionary rеlationships among spесiеs havе Ьееn rеfinеd Ьy ovеrlaying Ьеhavioг on phylogеniеs, thе сomparativеmеthod Ьy itsеlf, with its rеlianсе on statistiсal сorrеlations among Ьеhavioral outсomеs аnd eсologiсal forсеs, сould only providе a Ьroad-Ьrushundеrstandingof thе еvolution of animal soсiеtiеs.To movе Ьеyond what сritiсs (е.g.,Lеwontin 1979) с|aimеd wеrе ..just.sostoriеs'' and gain a mесhanistiс undеrstanding of есologiсal сausation, а Ьеttеr gгаsp of why partiсular soсiаl rеlationships among individuals dеvеlopеd in spесifiс сirсumstanсеswas nееdеd, and this rеquirеd thе dеvеlopmеnt of thеoriеs to ехplainindividual dесision mаking.

ЕmеrgingThеorеtiсal Framеworks Two diffеrеnt thеoriеs еmеrgеd, onе from soсial thеorists and onе from есologists.Why animаls should hеlp others, oftеn аt thе еxpеnsе of rеproduсing thеmsеlvеs' is a quеstion that pегplехеd biologists for сеnturiеs.Еvеn Darwin was puzzlеd aЬout why so mаny soсial insесts wеrе stеrilе. A major Ьrеakthroughoссurrеd whеn Hamilton (1,964)proposеd thе idеa of hiп sеlесtioп. Until thе mid-1960s thеrе was сonfusion аЬout thе units of sеlесtion.WynnеЕdwards (1962) сhampionеd thе viеw that soсial Ьеhavior еvolvеd as a mеansof rеgulating populations; hеnсе gгoup Ьеhavior wаs whеre sеlесtion opегаtеd.\(illiams (1966) сritiсizеd this viеw Ьy dеmonstratingthat most soсial intеraсtionsaugmеntеd thе fitnеss of individuаls that еngagеd in thеm. Hеnсеsеlесtionaсtеd on individuals. Br'rtif bеnеfitsof bеing soсial aссruе to individuals' thеn aссounting for thе еvolution of altruistiс aсts that dеmonstraЬly hеlp rесipiеnts Ьut aссruе no dirесt Ьеnеfits for altruists bесomеs a proЬlеm.Нamilton's insight was that individuals сan pass on thеir gеnеsnoт only dirесtly thr
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Soсiаl Bеbаuior апс]Sociobiologу 1972ь, 19741Trivеrs and Harе I976). Sinсе parеnts arе rеlatеd еqually to all thеir offspring, Ьut offspгing arе morе сlosеly rеlatеd to tlrеmsеlvеs than to thеir siЬlings, сonfliсt ovеr еХpесtеdinvеstmеntЬy parеnts will oftеn еmеrgе. In gеnеral, offspring will attеmpt to prеvеnt parеnts from еqually sprеading rеsourсеsamong all thеir offspring. Howеvеr, thе rеlаtionship bепveеn parеntal invеstmеnt and sехual сompеtition nray havе Ьееn thе most profound ехtеn. sion of kinship thеory for shaping thе study of soсial еvolution. Armеd with thе rеsults of Batеman,s(1948) study of fruit fliеs that showеd that rеproduсtion Ьy malеs and fеmalеs was limitеd by diffеrеnt faсtors, Trivеrs proposеd that whеn onе sех invеsts morе in thе rеaring of оffspring than thе othеr, mеmbеrs of thе lattеr will сompеtе for mеmЬеrs of thе formеr. In еssеnсе,thе sеx that invеstsmorе in rеaring Ьесomеsa limiting rеsourсе'and thе sех with ..ехсеss'' rеsourсеs should invеst hеаvily in mating асtivitiеs, inсludirrgfind. ing and guarding mеmЬеrs of thе paгеnting sеx. Thе sесond thеory еmеrgеd 1rom есology. Pionееring work Ьy Orians, .Willson Vеrnеr' and showеd that thе mating systеmof rеd-wingеd ЬlaсkЬirds dеpendеd on how есologiсal сonditions affесtеd thе sехеs in diffеrеnt ways (Orians 1969). Thеy slrowеd that within onе population Ьoth polуgyny and monogamy сould сoехist, and that thе Ьеlravior of fеmalеs induсеd this mating-systеm variation. Thеy arguеd that on landsсapеs with rеsourсе patсhеs that variеd in quality, malеs on those of thе highеst quality сould dеfеnd еnough rеsourсеsto suPport thе сlutсhеs of m:rny fеmalеs. on thosе of lowеr quality, howеvеr, tеrritorial malеs would Ье luсky if thеy wеге :rЬlеto .Whаt sесuгееnough rеsourсеsto support thе offspring сrfonе tЪmalе. madе thеir modеl uniquе was that it dеpеndеd on assеssmеnts Ьy fеrrralеs-thе polygyny thrеshold-to dеtеrminе whеthеr mating polygynously or monogamously was in a fеmalе'sЬеst еvolutionary intеrеst' Тhе undеrlying prеmisе that fitnеss dеpеndеd orr what othеrs wеrе doing sеt thе stagе for Мaynaгd Smith's (|977) insight tlrat thе еvolution of thе fouг major mating systеms is a gаmе in whiсh what is Ьеst for onе sеx dеpеnds on what is Ьеst for thе othеr. Maynard Smith proposеd tlrat whеthеr Onе sех should invеst in геaring сurrеnt offspring should dеpеnd on how likеly thе othеr sех Was to сontinuе rеaring thosе offspring. Sinсе parеnts' intеrеsts arе similar Ьut not always idеntiсal, Maynirrd Smith showеd that thеrе was a pair of strаtеgiеs' onе for thе mаlе and onе tЪr thе fеrrralе,thаt, whеn pеrformеd togеthеr, would lеad to an еvolutionarily stаЬlе stratеgy (ЕSS). Suсh a stratеgywould oссur only if it did not pay еithеr parеnt to dеpart from his or hеr stratеgy.Thus it was possiЬlе for Ьiparеntal сarе, uniparеntal сarе proffеrеd Ьy еithег sех' or no parеntal сarе at all to Ье an ЕSS undеr spесifiс есologiсаl сonditions. IWhatthе еnviгonmеnt dеtеrminеsis thе ехtеnt to whiсh paгеntalсarе is nееdеdto rеаr offspring. If only onе parеnt is nееdеd,thеn the likеlihood of еitlrегpartnеr dеsеrtingdеpеndson thе еasеof finding an additiоnal matе. For fеmalеs in partiсr'rlar' this likеlihood is also affесtеd Ьy thе еxtеnt to whiсh pаrеnting rеduсеs hеr fеrtility in futurе rеproduсtivе еpisodеs.Foг thе first timе soсial aspесtsof mating Ьеhavior сould Ье сhaгaсtеrizеd аnd tiеd to srlесifiс sеlесtivе forсеs. Sехuzrl asvmпrеtгiеs

providеd thе lеns for еnting options. And v mining whiсh sех th. еvolutiоnary history a Whilе thе soсial thе part of thе polygyny-t rangе of ll1aring svstеl а widеr rangе of есo[ potеntial for polygynу tion of thе limiting sе find it diffiсult to сontl in groups, or rеsourсе grеgatе without inсurr as in thе N4aynard Sm malеs; if fеmalеs wеrе for polygyny сould nol

Еmеrgеnсеof a Sу

Thе еlеmеntsof a synt h a m l 9 8 6 ) . F е m a l е sr v сausе thеir soсial rеlа dеmands of thе physiсэ sеminal rеviеw, thеsе and prеdation prеssu pеndеd mostly on solv safе sites for thеmsеlv mаtеs. oniy aftеr аss lаndsсаpеs wеrе dеtеr foг mаting opportunit aсtions Ьy Ьrееdingma Ьеhirvior ultimatеly lеd Ьy suЬadults and dеvе g е n е г a t i o n sа l s o с a п r еi сiеtiеs (Rubеnstеin 198 Thе synthеtiс modе] wеrе аbundаnt, еspес would Ье low еnough t aging or antiprеdator Ь and thе groups thаt fo dеfеndеd Ьy singlе ma sult. Flowеvеr, if rеsou tion among fеmales rr would vary, аnd fеmal than dеfеnding unstаЬ

Sociаl Behаuior апd Sociobiologу е parепtsarе rrlatеd еqually to all sеly rеlatеd tо thеmsеlvеs tharr to nеnt Ьу parеntswill oftеn еmеrgе. 1t parеntsfrom еqually sprеading :, thе rеlationshipЬеtwееnparеntal vе Ьееn thе most profound еxtеny of soсial еvolution. Armеd with rit fliеsthat showеd that rеproduсJiffеrеntfaсtors,Trivеrs proposеd aring of offspring than thе othеr' пЬеrsof thе fornrеr.In еssеnсе,thе limitingrеsоurсе,and thе sеx with :l mating aсtivitiеs'inсluding find. g sеХ. ogy. Pionеегing work Ьy orians' lg systепlof rеd-wingеdЬlaсkЬiгds ffесtеdthе sехеs in diffеrеnt ways lnе population Ьoth polygyny and Ьеhavior оf fеmаlеs induсеd this hat on landsсapеs with rеsourсе osе of thе highеstquality сould dесhеsof many fеmalеs.on thosе of vould Ье luсky if thеy wеге aЬlе to :fspringof onе fеmalе. What madе l on assеssmеntsby fеmalеs-thе r matingpolygynously or monogar intеrеst. lеndеd on whаt othеrs wеrе doing ) insight that thе еvolution of thе whiсh what is bеst for onе sеx dеnard Smith proposеd that whеthеr offspring shoцld dеpеnd on how g thosе offsprirrg.Sinсе parеnts' in. iсal, Мaynard Smith sl.lowеd that malе and onе for thе fеmalе. that. э an еvolutiоnarily stаЬlе stratеgy f it did not pay еithеr paгеnt to dеs possiЬlеfor biparеntal сarе, uniro pаrеntal Сareat all to Ье an ЕSS t thе еnvironmеntdеtеrminеs is thе r е a ro f f s p r i n g I. f o n l y o n е p a r с n t i s rеr dеsегtingdеpеndson thе еаsе of n partiсular' this likеlihood is also r е d u с е sh е r f е r t i l i t yi n f u t u r е г е p r o lspесtsоf mаtirrgЬеhavior сould Ье .сtivе foгсеs. Sеxual asymmеtгiеs

providеd thе lеns for idеntifying how rеsourсеs and prеdation affесtеd parеnting options. And whеn only onе pаrеnt wаs rеquirеd for rеaring, dеtеrmining whiсh sех thaг should Ье dеpеndеd on tradе-offs shapеd Ьy Ьoth еvolutionary history and сцrrеnt есologiсal сirсumstanсеs. !7hilе thе soсial thеorists Wеrе ехpanding thе Ьеhavioral dесision-making part of thе polygyny-thrеshold modеl to aссount for thе еvolution of thе full rangеof mating systеms' есologists wеrе ехpanding thе modеl to aссount for а widеr rangе of есologiсal dеtегminаnts.For Еmlen аnd Orling (1977), the potеnti:rlfоr polygyny dеpеndеd on Ьoth thе spatial and tеmporal distriЬution of thе limiting sеx. If fеmalеs wеrе widеly sсattеrеd' thеn malеs would find it diffiсult to сontrol morе than onе fеmalе. Altеrnativеly, if tЪmalеslivеd in groups, or rеsourсеs wеrе сlumpеd so that fеmalеs сould tеmporarilу aggгеgatеwithout inсurring muсh сompеtition, thеn polygyny сould rеsult. But as in thе Мaynагd Smith modеl' muсh would dеpеnd on thе Ьеhavior of fеmalеs; if fеmalеs wеrе rесеptivе mostly at thе samе timе, thеn thе potеntial for polygyny сould not Ье rеalizеd.

Еmеrgеnсеof a SynthеtiсThеory .!Vrang_ Thе еlеmеntsof а synthеtiс thеory wеrе сrystallizing (Rubеnstеin аnd ham 1986). Fеmalеs wеrе viеwеd as thе driving forсе of soсial еvolution Ьесausеthеir soсial rеlаtionships rеflесtеd thеir bеst rеsPonsе to mееting thе dеmarrdsof thе physiсal еnvironmеnt,and, as Alехandе r (|974) arguеd in his sеminal rеviеw, thеsе largеly fеll into two сatеgoriеs: rеsourсе distriЬution and prеdation Prеssurе. Maхimizing rеproduсtivе suссess Ьy fеmalеs dеpеndеdmostly on solving proЬlеms posеd Ьy aсquiring rеsourсеs or finding safе sitеs for thеmsеlvеs or thеir young rathеr than on finding or sесuring matеs. only аftеr assoсiatiorrsamong fеmаlеs and thеir distribuгions on landsсapеswеrе detеrnrinеddid malе stratеgiеsassoсiatеd with сompеting for mating opportunitiеs сomе into pIay' SuЬsеquеntrеsponsеsЬy fеmalеs to асtionsby brееdingmаlеs and, in turn, rеsponsеsЬy Ьrееdingmalеs to fеmalе bеhavioгultimatеly lеd to an еvolutionarily staЬlе mating systеm.But aсtions by suЬadultsand dеvеlоpmеnt of rеlationships among mеmЬеrs of diffеrеnt gеnеratiоnsalso сamе into play as soсial struсturеsdеvсlopеd in сomplеx soсiеtiеs(Rubеnstеin1986, 1994). Thе synthеtiс modеl prеdiсtеd that in еnvironmеnts in whiсh rеsolJrсеs wеrе abundant, еspесially whеn thеy wеrе еvеnly distriЬutеd, сompеtition would Ье low еnough to pеrmir fеmаlеsto aggrеgatе.If suffiсiеntlylаrge foragingоr antiprеdator Ьеnеfits сould Ье dеrivеd Ьy thеsе aggrеgating fеmalеs, and thе Е]roupsthat formеd wегe not too largе, thеn thеsе groups сould Ье dеfеndеdЬy singlе nralеs, and so сailеd harеrn_dеfеnsе polygvny would rеsult.Howеvеr, if rеsоurсеsWеrе morе patсhily distriЬutеd, so that сompеtition among fеmalеs was pеriodiсally intеnsifiеd, thеn fеmalе group sizеs would vаry, arrd fеmalе assoсiationswould Ьесomе morе tratrsitоry.Rathеr than dеfеnding unstaЬlе groups of fеmаlеs, malеs instеad would attеmpt to

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Sociаl Behаuior аnd Soсiobiologу dеfеnd rеsourсе patсhеs sought Ьy fеmalеs. In thеse systеms of rеsourсеdеfеnsе polygyny thе most aЬlе malеs would dеfеnd thе Ьеst patсhеs and thus gain aссеss to thе largеst numЬеr of fеmalеs for thе longеst pеriods of timе. If rеsourсеs wеrе distriЬutеd not only patсhily Ьut in patсhеs that wеrе largе, wеrе widеly sеparatеd' and fluсtuatеd sеasonally in aЬundanсе, thеn сompеtition among fеmalеs would Ье low. This would faсilitatе thе formation of largе groups providеd that fеmalеs сould rangе widеly and follow thе shifting loсations of pеaks in food aЬundanсе. Мalеs would thus Ье forсеd to еithеr follow thеsе largе groups and сompеtе for' and thеn tеnd' onе rеproduсtivе fеmalе at a timе (tllаndering polуgупу) or position thеmsеlvеs at thе intеrsес. tion of fеmalе migratory routеs and wait for fеmalеs to visit tЬem (lekking polуgупfl.In еithеr сasе intеnsе malе-malе сompеtition would gеnеratеa mating systеm Ьasеd on malе-dominanсе polygyny, and in thе lattеr сasе fе. malеs would Ье affordеd thе ехquisitе opportunity of simultanеously сom.$Иhеnеvеr paring many malеs Ьеforе сhoosing with whom to matе. rеsourсеs wеrе sparsеly Ьut somеwhat еvеnly distriЬutеd, high lеvеls of сompеtition would prеvеnt fеmalеs from forming groups. As a rеsult, individual fеmalеs would dеfеnd individual tеrritoriеs, thus еnsuring a rеgular supply of a rеnеwing rеsourсе. Sinсе solitary individuals who wеrе sеarсhing for mеmЬеrs of thе oppositе sех would faсе hеightеnеdprеdation risk' pairs would оftеn shаrе tеrritoriеs,and monogamy would rеsult. Until еmpiriсal studiеson antеlopе (Jarman 1974) and Ьats (Bradbury and Vеhrеnсamp 1977a,1977Ь) showеd how есology aсtually shapеd fеmalе distriЬutions' many of thе undеrlying assumptions оf this modеl wеrе supportеd only Ьy anесdotal сorrеlations.Jarman,s сlassiс study of Afriсan antеlopеsillustratеs how еnvironmеntal forсеs intеraсtеd with physiologiсal сonstraints to shapе thе mating systеm of а spесiеs. By shоwing how Ьody sizе affесtеd thе ways in whiсh diffеrеnt spесiеs pеrсеivеd and thеn rеspondеd to thе distriЬution and aЬundanсе of foragе and prеdators on grasslands, Jarman showеd why partiсular soсial systеms inсrеasеd survival and rеproduсtivе prospесts for partiсular spесiеs.Hе arguеd that thе smallеst-Ьodiеdspесiеs, suсh as did-dik (Маdoquа hirhii)' duikеrs (Сеphаlophиs sPP., Sуluicаprа spp.), suni (Neotrаgus mosсhаtus), and klipspringers (ОreotrаgL|s orеotrаgиs), геquirеd limitеd amounts of high-quality vеgеtation. But Ьесausе of thеir small sizе, suсh food itеms oftеn appеarеd to Ье widеly sсattеrеd. High lеvеls of сompеtition and intеnsifiеd risks of prеdation madе tеrritoгiality and monogamy appеar thе Ьеst stratеgiеs.Pairs gеnеrally livеd in woоdеd or shruЬ-riсh arеas whеrе moisturе еnaЬlеd vеgеtation to grow and rеnеw itsеlf wеll into thе dry sеason. By signaling tеrritorial ownеrship via sсеnt rathеr than Ьy mеans of sound or visual displаy, thеsеsmall-Ьodiеdspесiеsrеduсеd thе сhanсеs that any of a largе numЬеr of сarnivorеs would prеy upon thеm. As spесiеs inсrеasеd in Ьody sizе' Ьoth physiologiсally dеtеrminеd diеtary nееds and thе way aссеptablе foragе bесamе distributеd on thе landsсapе сhangеd. Sinсе сrypsis Ьесamе an untеnaЬlе antipгеdator stratеgy for largеr and morе widеly ranging spесiеs, forming groups bесamе thе Ьеst strаtеgy for suсh spесiеs to lowеr prеdation risk. Fortunatеly, with largеr sizе also

саmе an aЬility to suЬ it was patсhily distriЬu rееdЬuсk (Reduпса sp thе Ьеst patсhеs that fе distriЬutеd, whiсh oftе as еland (Tаurotrаgиs

еvеn thе lowеst-qual spесiеs viеwеd lаrgе < sourсе сompеtition wa .!7 with many fеmalеs. of a small suЬgroup o Systеms dеvеlopеd. Thе samе sorts of сс and Ьеhavioral dесisr othеr taxa. A Ьriеf sur p а г t е г n s .F o г t h е е q u i aЬlеs horsе (Еqиus са diffеrеnt rеproduсtivе t dеfеnd suсh groups, al arе widеly dispеrsеd,a ass (Ьquиs hemioпoиs Ьoliс сonstraints froпr l toriеs along travеlingrr points (RuЬеnstеin 19E In fеlids, fеmalеs rеl dеnsеly woodеd Ьесau and сonsumеd Ьеforе с whеrе Ьoth prеy and сr tions of fеmalеs form l vourеd (Paсkеr \986)' thеrе is prеssurе for mi malеs. Thus thе only h lеo). |n this plеntiful lс tary Ьесausе it сan safе For сanids, monoga foхes (Vulpes spp.) sor dogs (Lусаoп piсtиs) ; (Moеhlman t986). Tу to hеlp nourish|асrаt verЬaсk jaсkаl (Сапis l tеrs that сannot thеI smallеst spесiеs, howt small for a fеmalе; thr yеars whеn prеy rеsou thеir soon-to-Ье-fесun to dispеrsе. Thеy thеrеf

Soсiаl Bahаuior апd Soсiolэiologу lеs. In thеsе systеms of rеsourсеld dеfеndthе Ьеst patсhеs and thus :s for thе longеst pеriods of timе. If .ily Ьut iп patсhеs that wеrе lаrgе, sonallyin abundanсе' thеn сompе; would faсilitatе thе formation of angеwidеly and follow thе shifting alеs would thus Ье forсеd to еithеr 'r, and thеn tеnd, onе rеproduсtivе position thеmsеlvеs at thе intеrsес- for fеmalеs to visit tЬem (lеk.king ralе сompеtition would gеnеratе a polygyny, аnd in thе lattеr сasе fеppoгtunityof simultanеously сom.s7hеnеvеr whom to matе. rеsouгсеs riЬutеd,high lеvеls of сompеtition ups. As a rеsult, individual fеmalеs еnsuringa rеgular supply of a rе* ls who wеrе sеаrсhing for mеmЬеrs d prеdationrisk, pairs would oftеn еsult. "nan 1974) and Ьаts (BradЬury and есologyaсtuаlly shapеd fеmalе disptions of this modеl wеrе supportеd сlassiсstudy of Afгiсan аntеlopеs ilaсtеdwith physiologiсal сonstraints By showing how Ьody sizе affесtеd :ivеd and thеn rеspondеd to thе disJ prеdators or-rgrаsslands, Jarman nсrеasеd survival and rеproduсtivе rеdthаt thе smallеst-Ьodiеdspесiеs, <еrs(Сеphаlсlpbus spp., Sуlviсаprа klipspringеrs (Оreotrаgus oreotrа-quality vеgеtation. But bесausе of 'pеaгеdto Ье widеly sсattеrеd. High ;ks of prеdation madе tеrritoriality s. Рairs gеnеrallylivеd in woоdеd or vеgеtationto grow and rеnеw itsеlf :rritorial ownеrship via sсеnt rаthеr ', thеsеsmall-bodiеdspесiеsгеduсеd f саrnivorеswould prеy upon thеm. r physiologiсallydеtеrminеd diеtary зсamеdistriЬutеd on thе landsсapе lblе antiprеdator stratеgy for largеr ng groups bесamе thе Ьеst stratеgy l. Fortunatеly,with largеr sizе also

сamе an aЬility to suЬsiston morе aЬundant, lowеr-quality vеgеtation..i7hеn it was patсhily distriЬutеd' as Was thе саsе for impala (Aеpуcеrсlsmelаmpus), гееdЬuсk(Reduпса spp.), and sоmе gаzеllеs (Gаzеllа spp.), malеs dеfеndеd thе Ьеst patсhеs thаt fеmаlеs prеfеrrеd. !Иhеn thе vеgеtation was morе еvеnly distriЬutеd,whiсh oftеn rеsultеdsimply from thе faсt that largеr spесiеssuсh as еland (Tаurotrаgus orvх) and Сapе Ьuffal o (Sупcеros cаffer) сould usе еVеn thе lowеst-quality items, largеr groups formеd. Bесausе thе largеst spесiеsviеwеd lаrgе сontinuous swards of a landsсapе as aссеptaЬlе, rеsouгсесompеtition was virtually еliminatеd,аnd many malеs сould assoсiatе rvith many fЪnralеs.With suсh high lеvеls of rnale_nralесompеtition' dеfеnsе of a smal] suЬgгоr'rpof fепralеs ЬесanrеimpossiЬlе, and dominanсе dеfеnsе sуstеmsdеvеlopеd. Thе samе sorts of сonnесtions bеtwееn сhanging есologiсal сirсumstanсеs and Ьеhavioral dесisitln making shaреd thе typеs of soсiality еxhiЬitеd in othег taхa. A Ьriеf survеy of mammals illustratеs somе of thе morе gеnеral pattеrns.For thе еquids, thе сlosе assoсiation Ьеtwееn food and watеr еnaЬlеs horsе (Еquus саbаllus) and plains zeЬra (Еquus burсhelli) fеmalеs of diffеrеntrеproduсtivеstatеsto assoсiatеpеrmanеntly.Thus malеs arе aЬlе to dеfеnd suсh groups, аnd so-сallеd harеms form. .Whеn thеsе two rеsourсеs arе widеly dispеrsеd, as foг Gгеvy's zеЬra (Еquus grеuуi) and thе Asiatiс wild ass (Еquus hеmioпous), fеmalеs of diffеrеnt statеs arе prесludеd by mеta. Ьoliс сonstraintsfrom foraging togеthеr.As a геsult,mаlеs сompеtе for tеrri_ toriеsalong trаvеling routеs that takе fеmalеsfrom fееding arеas to watеring points (RuЬеnstеin1986, 1994\' In fеlids, fеmаlеs rеmain sеparatеdwhеn food is sсarсе and haЬitats arе dеnsеlywoodеd Ьесausеin suсh сirсumstanсеsindividuаl prеy сan bе сaught and соnsumеd Ьеforе сompеtitoгs сan intеrvеnе.In morе opеn haЬitats and whеrе Ьoth prеy and сompеtitors arе lаrgе arrd muсlr morе numеrous, сoalitions of fеmalеs fоrm to help hold on to kills until thеy arе сomplеtеly dеvourеd (Paсkеr 19s6). If thеsе fеmalе сoаlitions arе thеmsеlvеs largе, thеn thеrеis prеssurеfor malеs to аggrеgаtеto сontrol rеproduсtivе aссеssto fеmalеs.Thus thе only higЬly soсial fеlid is thе sаvanna-living|ton (Pаnthеrа Ieo)' In this plеntiful landsсapе thе lеoparсi (Pаnthеrа pаrdus) rеmains solitary Ьесauseit сan safеly сaсhе its laгgе prеy in trееs. For сanids, monogamy is thе rulе. But variations do oссur: small-Ьodied foхes (Vulpеs spp.) somеtimеs ехhiЬit polygyny, and largе_Ьodiеdhunting dogs (Lусаrlп piсtus) arrd tirnЬеr wоlvеs (Сапis lupus) dеvеlop polyanсlry (Мoеhlman 19s6). Typiсally сanids nееd hеlp from norrЬrееding foгagеrs to hеlp nоurish laсtating mothеrs. Fоr thе midsizеd iaсkals. suсh as thе silvеrЬaсk 1aсka|(Сапis mesomelаd, thе hеlpеrs arе young from prеvious lit. tеrs thаt сannot thеmsеlvеs find suссеssful Ьrееding loсations. For thе smallеst spесiеs, howеvеr, prеpartum invеstmеnt in young is rеlativеly small for a fеmalе; thus hеr matе providеs all thе hеlp that is nееdеd. In yеarswhеn prеy rеsourсеs arе vеry high, сompеtition Ьеtwееn mothеrs and thеirsoon-to-Ье-fесunddaughtеrs is low, and thеir dаughtеrs arе not forсеd to dispеrsе.Thеy thеrеtЪrеprovidе nеighЬorirrg mаlеs with additionаl mating

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Soсiаl Behаuior апd Soсiobiologу opportunitiеs, and polygyny rеsults. For thе largеst-Ьodiеd spесiеs, howеvеr, fеmalе prеpartum invеstmеnt is vеry high, and thеy nееd all thе hеlp thеy сan gеt. To еnlist thе support of othеr adult malеs that must hunt сoopеrativеly to сapturе largе prеy' a dominant fеmalе not only kills thе offspring of othеr fеmalеs in thе group Ьut also matеs with thеir matеs so that thеsе malеs Ьеhavе as if thеy arе thе sirеs of thе dominant fеmalе's young. HеnсЁ, dеpеnding on sizе-dеtеrminеdmеtaЬoliс investmеntsand nееds' soсial systеms of сanids сan vary from polygyny to polyandry, and thеy somеtimеs usе thе sеrviсеs of juvеnilе or аdult nonЬrееdеrs to hеlp rеar offspring. As thеsе еxamplеs illustratе, thе сomparativе mеthod Ьеnеfitеd trеmеndously Ьy thе dеvеlopmеnt of soсioесologiсal thеory that еmphasizеd thе importanсе of fеmalеs and thеir rеlationship to thе еnvironmеnt in struсturing soсiеtiеs.But aspесtsof kinship and dеmography also сomе into play. As Нamilton's rulе illustratеs, thе strongеr thе dеgrее of rеlatеdnеss among rеlativеs, thе morе likеly altruists arе to еnhanсе thе rеproduсtivе opportunitiеs of kin whilе inсurring сosts assoсiatеd with diminishеd pеrsonal rеproduсtion. Thus in thе prеvious еxamplеs, it is not surprising to find that thе сoalitions that form among lionеssеswhеn thеy arе protесting kills and among male lions whеn thеy arе dеfеnding mating opportunitiеs with fеmalеs arе formеd most oftеn among full siЬlings (Paсkеr 1986); nor is it surprising that thе hеlpеrs jaсkal adults kееp to rear additional offspring are thеmsеlvеsthе full siЬlings of thе offspring Ьеing raisеd (Moеhlman 1986). In gеnеral, strong kinship lowеrs thе thrеshold for thе appеaranсе of altruistiс and сoopеrativе Ьеhavior and may suЬstantially affесt thе сosts of living in groups. Thе struсturе of jaсkal soсiеtiеs not only highlights thе importanсе of kin sеlесtion Ьut also illustratesthе faсt that mаny soсiеtiеsсonsist of adults of diffеrеnt gеnеrations' somе of whiсh сarе for offspring that arе not nесеssar. ily thеir own. Мany insесts in thе ordеrs Hymеnоptеrа and Isoptеra and aЬout Зу" of birds and mammals show srrсh systеms сomposеd of сoopеrativе brееdеrs (Еmlеn 1997)' Up to this point thе еmеrging synthеtiс thеory of soсiality has largеly trеatеd all adult fеmalеs and malеs as indеpеndеntdесision makеrs; rеsponding tо есologiсal сonditions shapеd thе Ьеst rеsponsе for fеmalеs, whiсh in turn сonstrainеd thе Ьеst rеsponsеs of malеs. But in many soсiеtiеs mature offspring rеmain and help parеnts rеar additional off. spring. Ultimatеly, undеrstanding why individuals forgo pеrsonal rеproduсtion to hеlp сlosе rеlativеs rеproduсе pгovidеs insights into how thе Ьalanсе bеtwееn dеspotiс and еgalitariаn soсial rеlationships, as wеll as thе dynamiсs of familiеs, is dеtеrminеd Ьy intеraсtionsаmong есology, kinship, аnd domi. nanсе (Еmlеn 1'995). In most spесiеs, offspring lеavе homе Ьеforе Ьrееding. But in many soсial insесts, primatеs, and othеr mammals and Ьirds, onе sеx rеtаins tiеs to parеnts, somеtimеs pеrmanеntly' сrеating multigеnеrational familiеs. Gеnеrally, offspring postponе dispеrsing whеn Ьrееding opportunitiеs arе limitеd еlsеwhеrе. Есоlоgiсal сonstraints assoсiatеdwith limitеd Ьrееding sitеs, matеs'

or food rеsourсеs oftt p r o d u с е а d d i r i о n а sl i failing to prоduсе an forming whеn сondit But whеn thеy form' as many studiеs havе If family сomposit сhangе. Bесausе сlos spring rarеly attеmpt sеx. Thus сompеtitior nitiеs rеmains low. If, thеn from the pеrspес will likеly produсе с. matе and rеmains in offspring of this pаir, dеgrее to whiсh thе rе еratеd will dеpеnd on ship Ьеtwееn thе tw геproduсtion аmong l valuе of 1 whеn thе Ьr whеn Ьrееding is сom pгoduсtion oссurs wil by dominants if suЬo natеs if thеy lеavе; (3 and (4) thе magnitudе Ьrееdеrs. $Иhеn oppo high, thе dominanсе d thе Ьеnеfits of having breеder will Ье sеlесtе (Rееvе and Ratniеks 1 options еlsеwhеrе and damagе on thе еstaЬ .!7rеgе 1992), Groovе (FaaЬorg et a|. 1995), 1994) have shown, do likеly whеn hеlpеrs arе kin sеlесtion. But as might Ье ехp and lеaving dесisions t quеstionеd whеthеr dс groups (Сlutton.Broсk ativе brееding soсiеtiеs tions Ьasеd on kinship : suсh as mutualisms tha that еmеrgе as mееrka сomе into play.

So сiаl B ehаtlior апd So ci сlbiolсlgу : thе lаrgеst-Ьodiеdspесiеs' how:y high, and thеy nееd all thе hеlp rеr adult malеs that nrust hunt сo. inant fеmаiе not only kilis thе offr l s o n r а t е sw i t h t l r е i r m a t е s s o t h а t :s of thе dominant fеmalе's young. :taЬoliсinvеstmеntsand nееds' sogyllу to polyandry, and thеy somеadult nonbrееdеrs to hеlp rеar parаtivеmеthod Ьеnеfitеd trеmеnogiсal thеоry that еmphasizеd thе ; h i pr o t h е е n v i r o n t n е n ti n s t r u с t u r lеmographyalso сomе into play. As : thе dеgrее of rеlatеdnеss among е n h a n с еt h е r е p r o d u с t i v еo p p о г t u iatеd with dimirrishеd pеrsonal rеllеs, it is not surprising to find that i whеn thеy arе protесting kills and ding mating opportunitiеs with fеs i Ь l i n g s( P a с k е rl 9 8 6 ) ;n o r i s i t s u r )еp to rеar additional offspring arе ing bеing raisеd (Moеhlman 1986). эsholdfoг thе appе;rranсеof altruistЬstantiallyaffесt thе сosts of living nly highlights thе importanсе of kin t many soсiеtiеsсonsist of adults of е for offspringthat arе not nесеssarеrs L{ymеnoptеra and Isoptеrzr and suсh systеmsсomposеd of сoopеraэint thе еmегging synthеtiс thеory of ralеsand malеs as indеpеndеnt dесi:onditionsshapеd thе Ьеst rеsponsе thе Ьеst rеsponsеsof malеs. But in and hеlp parеnts rеar аdditiona| offndividtlаlsforgo pеrsonal rеproduс' ovidеs insights irrto how thе bаlаnсе .еlationships, as wеll аs thе dynamiсs kinship, and domiесology' аmong ; Ьеforеbrееding.But in many soсial n d Ь i r d s ,o n е s е х r е t a i n st i е s t o p a r familiеs. Gеnеrally, nultigеnеrаtional lеdingopportunitiеs arе limitеd еlsеl w i t h l i m i t е d Ь r е с d i n g s i r е s ,t n a t е s '

or food rеsourсеsoftеn makе thе option of stаying homе and hеlping parеnts produсеadditional siЬlings Ьеttеr than dispеrsing еarly and almost сеrtainly failing to produсе any offspring. Thus marry family groups will Ье unstaЬlе, formingwhеn сonditions ilre poor and disЬаnding whеn сonditions аге good. But whеn thеy form, intеrgеnеrationalсoopеration should Ье сommonplaсе, as many studiеs havе shown. If family сonrposition сhangеs, howеvег, thеn soсial dynamiсs сan also сhangе.Bесause сlosе inЬrееding oftеn has dеlеtеriousеffесts' rеtаirrеdoff. springrarеly attеmpt to matе with a pаrеnr or сlosе rеlativе of thе оppositе sех.Thus сompеtition with thе samе-sеxеdparеnt for rеproduсtivе opportunitiеsrеmains low. If, howеvеr, a parеnt diеs and is rеplaсеd Ьy a nonrеlativе, thеn fгom thе pеrspесtivеof nondispеrsingadults, nеw mirting opportunitiеs will likеly produсе сonfliсt. Similarly' if a nondispегsing adult aсquirеs а matе and rеmains in thе group and limitеd rеsourсеs arе сonsuпled Ьy thе offspringof this pair, thеn сompеtition wi1l Ье hеightеnеd.In еithеr сasе thе dеgrееto whiсh thе rеproduсtivе aсtivitiеsof thе nondispеrsingadult arе tol. еratеdwill dеpеnd on thе stгеngthof thе dominanсе-suЬordinrrtionrеlationship Ьеtwееn thе two. Reproductiue sheц, desсriЬеs thе distriЬution of rеproduсtion among Ьrееding adults within familiеs and сan rаngе from a valuеof l whеn thе Ьrееdеrin сhargе garnеrs all rеproduсtion to a valuе of 0 whеn Ьrееding is сomplеtеly egalitariаrr.Thе dеgrее to whiсh sharing ot rеproduсtiоn oссurs will dеpend upon four сonditions: (1)thе Ьеrrеfitdеrivеd Ьy dominants if suЬordinatеs stay; (2) thе rеproduсtivе suссеss of subordinatеsif thеy lеаvе; (3) thе gеnеtiс rеlatеdnеssamong potеntial сoЬrееdеrs; and (4) thе mаgnitudе of thе domirranсе rеlationshiр bеtwееn potеntial сobrееdеrs. \ff/hеn opportunitiеs for thе suЬordinatе to Ьrееd еlsеwhеге aге high, thе dominanсе diffегеnсеamong Ьrееdеrsis small, kinship is low' and thе Ьеnеfitsof having hеlpегs to thе dominant аrе high, thеn thе dominant Ьrееdеrwill Ье seleсted to pay а high stауi?lg inсеntiuе and pеасе ittсепtiz,е (Rееvеand Rаtniеks 1993) to еnsurе that a hеlpеr hеlps sinсе l-rеlpеrshavе options еlsеwhеrе and, Ьесausе of nеarly еqual fighting aЬility, сan infliсt damagе on thе еstaЬlishеd Ьrееdеr. As studiеs on Ьее-еatеrs(Еmlеn and Wrеge 1992), Groovе-Ьillеd anis (Vеhrеnсamp 1978), Galipagos Hawk (FaaЬorget a|. |995|, and mongоosеs (Crееl аnd \Wasеr1991; Kеanе еt al. 1994) Ьave shown, dominant Ьrееdеrs making ..сonсеssions'' to hеlpеrs is likеly whеn hеlpеrs arе not сlosе kin sinсe thеy gain littlе indirесt Ьеnеfitviа kin sеlесtion. But as might bе еxpесtеd, variants to this sеt of rulеs that shаpе staying and lеaving dесisions of hеlpеrs oссur. Сlutton-Broсk and сollеaguеs havе quеstionеdwhеthеr dominants havе full сontrol ovеr rеproduсtion within gloups (Сlutton-Broсk еt al. 2000). Thеir studiеshаvе shown that in сoopеr_ ativе Ьrееding soсiеtiеsof mееrkats, lеvеls of сonсеssions do rrot fit prеdiс. tionsbasеd on kinship and thе nееds of dominants' As a rеsult, othеr fасtors' suсhas mutualisms that еnhanсе rеproduсtion for еvеry group mеmЬеr and that еmегgеas mееrkat groups gеt lаrgег (Сlutton-Bгoсk еt аl. 2002.), maу сomеinto play.

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Soсiаl Behаuior аnd Soсiobiologу

Additional Soсial Gluеs As mееrkats illustratе, not all soсiеtiеsnееd Ье hеld togеthеr Ьy thе gluе of kinship. Rеlationships Ьuilt around сoopеration rathеr than altruism or Ьasеd on mutualism and rесiproсity сan havе just as strong an еffесt and providе thе opportunitiеs for diffеrеnt typеs of soсiеtiеs to еvolvе. Rеlationships arе Ьuilt upon rеpеatеdintеraсtionsthat сan involvе сompеtitivеand сoopеrativе еlеmеnts. Manipulating thе naturе of pеrsonal rеlаtionships and thosе of сompanions should also dеtеrminеthе еxistеnсеand сharaсtеristiсsof many soсiеtiеs. Trivеrs (1972a) Was thе first to suggеstthat rесiproсity сould play an important rolе in shaping soсiеtiеs.If individuals Wеrе to aid a strangеr Ьy inсrеasing its survival or futurе rеproduсtion at somе сost tO sеlf in tеrms of diminishеd rеproduсtion' thеn suсh Ьеhavior сould only Ье maintainеd in a population if thе rесipiеnt wеrе to еvеntually rеpay thе сosts inсurrеd by thе altruist. This сonсеpt has Ьееn formalizеd as thе prisoner's dilemmа, whеrе two individuals havе two altеrnativеs-сoopеratе or dеfесt. Мutual сoopеration, usually Ьy staying truе to еaсh othеr dеspitе attеmpts Ьy au. thoritiеs to сajolе onе Partnеr to tufn on thе othеr, providеs a highеr rеward (R) than if thеy both dеfесt and arе punishеd /P/. If only onе partnеr turns on thе othеr' hоwеvеr, then thе sizе of thе tеmptation (T) nесеssaryto Ьrеak thе partnеrs' сoopеration еnaЬlеs thе сhеat to do Ьеst of all. Сonvеrsеly' thе partnеr who rеmains сoopеrativе to thе еnd is thе suсkеr and rесеivеsthе lowеst rеward (S/.As long as payoffs arе ordеrеd Т > R > P > s, dеfесting is favorеd sinсе it providеs thе grеatеst short.tеrm Ьеnеfit. If, howеvеr, suсh situations oссur frеquеntly and thе nцmЬеr of individuals in a soсiеty is small, thеn pairs of individuals will find thеmsеlvеs intеraсting timе and again. In suсh a sеtting, dеfесting is no longеr thе Ьеst stratеgy. Rathеr, сoopеration doеs bеst' and thе taсtiс thаt oftеn providеs thе grеat. еst long-tеrm rеWard is tit-for.tаt (TFT; Aхеlrod and Нamiltorr 1981)' in whiсh intеraсtants сoopеratе initially and сontinuе to do so until a partnеf dеfесts. If dеfесtiоn oссurs' thеn thе othеr partnеr dеfесts and сontinuеs to matсh thе Ьеhavior of thе initial dеfесtor. If thе initial dеfесtor again сoopеratеs' thеn thе rеspondеr is instantly forgiving and сoopеratеs as wеll. TFT сan rеsist invasion Ьy a stratеgy of purе dеfесtion. But sinсе it is еqually as rеwarding as a stratеgy of always сoopеrating, TFT сan Ье supеrsеdеdby suсh a stratеgy via drift. Sinсе a purеly сoopеrativе stratеgy саn Ье invadеd by thе sеlfish stratеgy of dеfесtion, thе stratеgy of tit-for-tat сannot Ье truly an ЕSS, Ьut it сomеs сlosе. Thе logiс of this argumеnt suggеsts that struсturing soсiеtiеs on rесl. proсity alonе will Ье diffiсult. Kinship сan always providе a strong foun. dation sinсе it rеduсеs thе nееd of fully rеpaying dеlayеd Ьеnеfits. By сoopегating mutually to solvе сommon proЬlеms, partnеrs may Ьеnеfitto suсh a lаrgе ехtеnt that thе tеmptation to dеfесt rеmains low еnough that

a suсkеr doеs Ьеttе bу-product mutuаlis of what a partnеr dс Studiеs on a variеt Long-tеrm studiеs of Paсkеr 1991) and Stа Ьy adopting individu ilarly, strong rеlation fantiсidal malеs or prеdаtors providеd si ing alonе.

Sосial Variants al

As thе еxamplеs of fa dеnsity and thе intеn tеrritoriеs with suffiс rеsponsiblе for favori of hеlpеrs. Thus dеm sеx ratio and agе stru vitаl гatеs, will shap spесiеs variation as е plе, wеrе agе spесifiс thеn high Ьrееding sе tionships would gеnе of moгtality Wеrе rе сommon. Sinсе somе thе variation in сanid ulеs сan havе importa Thе synthеtiс modt еnvironrnеntal fеatur mals. In many сasеs1 systеm of soсial orgа сonditions. In еquids transitory groups whс populations movе fr< сhangе. As was founс Statеs, whеrе food an diffеring nееds сan с arеas arе forсеd to еs spond Ьy dеfеndingtl and harеmlike soсiеti Soсial variation' ho Variation in sосial str

Sociаl Bеhаuior апd Soсiolэiologу

hеld togеthеrЬy thе gluе of kint rirthеrthan altruism or Ьasеd as stгongan еffесt and providе :iеsto еvolvе.Rеlationshiрs аrе l v ес о m p е t i t i v еа n d с o o p е r a t i v е lnal rеlationshipsand thоsе of nсе and сharасtегistiсsof mаny l r t r е с i p r o с i t yс о u l d p l a у a n i m lls wеrе to aid a Strangеr Ьy inat somе сost to sеlf in tеrms of r сould only Ье maintainеd in a lly rеpay thе сosts inсurrеd Ьy zеd аs the prisсlпеr's dilеmmа, s_сoopеratе or dеfесt. Мutual h othеr dеspitе attеmpts Ьy au,hе othеr, pror,idеs а highеr rеunishеd /P). If only onе partnеr thе tеmptation (T) nесеssary to е сhеat to do Ьеst of all. Сonivе to thе еnd is thе suсkеr and ryoffsarе oгdеrеd T> R > P > s, grеatеstshort-tеrm Ьеnеfit. If, nd thе numЬеr of individuals in w i l l f i n d t h е m s е l v е si n t е r a с t i n g g is no longеr thе Ьеst stratеgy. 'iс that oftеn prоvidеs thе grеatхеlrod and Hamiltorr 1981), in :ol-ltinuе to do sсl until a pаrtnеr p a r t l . l еdг е f е с t sа n d с o n t i n u е s t o [ г h е i n i t i а ld е f е с г o га g a i n с o o p ,ing and сoopеratеsas wеll. TFT fесtion.But sinсе it is еqually as ting' TFT сan Ье supеrsеdеd Ьy pеrativеstratеgyсan Ье invаdеd :еgyof tit.for-tat сannot Ье truly a t s t r u с t u r i n gs o с i е t i е s o n r е с i r аlwаys providе ir strong foun. ' rеpaying dеlayеd Ьеnеfits. By 'oЬlеms'partnеrs may Ьеnе{it to dеfесtrеmains low еnough that

a s u с k е r d o е s Ь е t t е r t h a n a d е f е с t o r . . W е s t - Е Ь е r h a r d( 1 9 8 9 ) t е r m s t h i s bу-produсt mutuаlistп Ьесаusе сoopеration is univеrsаlly Ьеst rеgardlеss of what a partnеr doеs. Studiеson a variеty of spесiеssuggеstthat mutualism сan shapе soсiality. Long-tеrm sttrdiеsof lions Ьy Paсkеr (Paсkеr and Ruttan 1988; Sсhееl and Pасkеr 1'991')and Standеr (1992) showеd that only Ьy hunting togеthеr and by adopting individuаl rolеs wеrе lions likеlv to Ьгing down lаrgе prеy. Sim_ ilarly,strong rеlаtionshipsamong fеmalеsto protесt сuЬs from attaсks Ьy infantiсidаl malеs or to hold on to prеy in thе faсе of othеr marauding prеdаtorsprovidеd simultanеous Ьеnеfitsthat сoцld not Ье obtainеd Ьy aсting alonе.

Soсial Variants and Altеrnativе Stratеgiеs As thе ехamplеs of fаmiliеs with сoopеrаtivе brееdеrsshow, high population dеnsity and thе intеnsifiеd сompеtition it еngеndеrs in thе sеarсh for sr.ritaЬlе tеrritories with suffiсiеnt food or haЬitaЬlе Ьurrows is thе faсtor ultimatеly rеsponsiЬlеfor favoring thе еstaЬlishmеntof сoalitions аnd thе rесruitmеnt of hеlpеrs.Thus dеmographiс fасtors, suсh as populаtion dеnsity, as wеll as sеx ratio and agе stгuсturе that rеsult frorn diffеrеnсеs in phenotypе-spесifiс vital ratеs, will shapе pattеrns of soсial organization and lеad to withinspесiеsvariation as есologiсal сirсumstanсеsсhangе. If mortality, for еxаmplе, wеrе agе spесifiсand highег for prеrеproduсtivеfеmalеs than for malеs' thеn high Ьrееding sеx ratios (malеs/fеmalеs)wоuld rеsult, and mating rеlatiorrshipswould gеnеrally Ьесomе morе polyandrous. If sех.spесifiс pattеrns of mortality wеrе rеvеrsеd, howеvеr, thеn polygyny would Ьесomе morе сommon. Sinсе soше of thеsе nrortality сonсеrns wеrе also rеsponsiЬlе for thе vаriation irr сarrid soсiаl struсtuге dеsсriЬеd еarliеr' thеsе mortality sсhеdulеsсan hаvе iпrpoгtant сonsеquеnсеs. Thе synthеtiс modеl of soсiality that is еmеrging shows that a variеty of еnvironmеntalfеаturеs influеnсе thе pattеrns of soсiаlity еxhiЬitеd Ьy animals' ]n many сasеs thеsе pattеrпs arе flеxiblе, and spесiеs сan vary in thе systеmof soсial organization thеy ехhiЬit dеpеnding upon еnvironmеntal сonditiоns. In еquids' for ехamplе, although fеmalе assеs typiсally livе in transitorygroups whosе mеmЬеrshipсhangеs (RuЬеnstein1986,1994) wЬen populations movе from arid to mеsiс arеas, soсial rеlationships сan also сhangе.As was found on an island off thе сoаst of thе southеastеrnUnitеd Statеs'whеrе food and Watеr arе aЬundant and сlosе togеthеr,fеmalеs with diffЪringnееds сan сoalеsсе into pеrmanеnt groups. Мalеs, whiсh in arid arеаsarе forсеd to еstaЬlish tеrritoriеs along routеs to and from watеr, rеspond Ьy dеfеnding thеsе groups muсh likе malеs of horsеs, thеir сlosе kin, and harеmlikе soсiеtiеsеmеrgе. Soсiаl variation, howеvеr' is not limitеd to diffеrеnсеsamong populаtions. Vаriаtion in soсial stratеgiеsсan еvolvе within populations sinсе not all indi-

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Soсiаl Behаuior апd Soсiobiologу viduals arе еqual; diffеrenсеsin ownеrship and past ехpеriеnсесan affесtthе outсomе of intеraсtions.If individuals irrtеraсtrеpеatеdly,thеn thе naturе of thеir intеraсtions will сhangе ovеr timе so th?1tсontеsts еnd morе quiсkly and pеaсеaЬly, with suЬordinatеs suЬmitting to dominants. In small or modеratеly sizеd groups, hiеrarсhiеsform and soсial rolеs Ьесomе сodifiеd. Although all individuals' rеgardlеssof rаnk, Ьеnеfit whеn sеrious fighting is rеduсеd Ьесausе Ьoth winnеrs and losегs bеnefit Ьy rеduсing wastеd tinrе on outсomеs that аrе virtually assurеd, dominants typiсally dеrivе thе grеatеstrеproduсtivе Ьеnеfits. In ехtеndеd fаmiliеs of сoopеrativе Ьrееdеrs, dominanсе plays an important rolе in dеtеrmining whеthеr rеproduсtion is morе or lеss еqually apportionеd among adult group mеmЬеrs. !0hеn dominanсе is еxtrеrтlеand kinship is low, rеproduсtivе options for adults arе limitеd as thеy Ьidе thеir timе proсееdingalong normаl ontogеnеtiс trajесtoriеsеn routе to rеproduсing.In suсh situations shortсutsto Ьrееding arе oftеn favored, еspесially if mortality ratеs of adults arе sizе or agе spесifiс and arе grеatеr for largеr and oldеr malеs. Trading off longеvity with low ratеs of rеproduсtion for сopious rеproduсtion ovеr a slrort pеriod сan lеad to disсrеtе sizе polyrnorphisms-so-сallеd altеrnativе rnalе mating stratеgiеs-within sехеs within populаtions. oftеn thе typiсal stratеgy adoptеd Ьy oldеr and largег malеs of dеfеnding harеms or rеsourсеsyiеlds thе most rеproduсtivе gains during a Ьrееding sеason' Ьut it oftеn inсurs a high сost as wеll. Bесausе displaying' fighting, attraсting thе attеntion of Prеdators, and dеlaying rеproduсtion whilе gгowing arе all сostly aсtivitiеs, malеs that adopt lеss it.tstаntanеously suссеssfulbцt also lеss сostly taсtiсs сan flourish. Thе maintеnanсе of suсh altеrnativе mating pattеrns is сommon among many spесiеs of insесts, fish' amphibians, Ьirds, and mamnrals. For ехam. plе, in Ьluеgill sunfish (Lepomis mасroсbirus) malеs typiсally dеfеnd nеst sitеs whеrе thеy display' attraсt fеmalеs' i:rrrdthеn fегtilizе аnd guard thе еggs thеy lay (Gross and Сharnov 1980). Sinсе only thе largеst malеs havе thе aЬility to dеfеnd nеst sitеs, thеy must dеlay Ьrееding for ovеr sеvеn yеars. As a rеsult' smallеr and youngеr malеs havе еvolvеd various сuсkolding stratеgiеsthat may in fасt Ье еqually suссеssfulеvolutionarily. In onе, thе so-сallеd snеak Ьеgins Ьrееding at two yеars of аgе' Although vеry small, suсh snеaks arе virtually all tеstеs and bесausе of thеir inсonspiсu. ousnеss сan divе from thе surfaсе just as a mating pair rеlеasеsspеrm and еggs. By еxuding largе volumеs of spеrm' somе fеrtilizе a fеw еggs. In thе othеr, malеs dеlay Ьrееding for as long as do fеmalеs. By Ьеing thе samе sizе and сoloг as fеmalеs, thеsе malеs join thе mating pair and apparеntly fool thе displaying пrаlе ir-rtothinking that hе is сourting two fеmаlesrаthеr than just onе. As thе original pair rеlеаsеs its gamеtеs' thе fеmalе mimiс doеs too, thus fеrtilizing somе of thе fеmalе's еggs. For thеsе two stratеgiеs to Ье еqually suссеssful altеrnativеS' thе сosts and Ьеnеfits of еaсh must vary invеrsеly with thе frеquеnсy of individuals that adopt thеsе taсtiсs.Al. though thеy somеtimеs do, as in thе сasе of thе Ьluеgill sunfish, in othеr spесiеs thеy do not.

Undеrlying N Control to Sе

Dесision making parisons of сosts tiсulаr soсiаl vа proсеssеd аnсl us еnt lеvеl of arrаly еithеr why indivi was triggеrеd. М Ьining thе two t< soсial Ьеhаvior. onе forпr of ir ganizеs Ьеhavior physiсal or soсia at thе right timе, rеquirеs сoсlrdinа animals arе rеird mate' maturе Е]a for thе transition fеaturеs must Ье whеthеr thеy aсt thеn сoordirrirtin formation florv. L possiblе. Anothеr typе o ior еmеrgеs froпЬеhavior viеwеd а sсalе thеy appеar may assеmblе in р ditions, Ьut whеtt and sizеs dеpеnds pulsion, attrасtio сoцnt for thе sizе Using a sеt of hit сompеtition and lеaguеs (|996\ sЬ tеndеnсiеs to frag induсе thеsе triln сlosе nеighЬors. I\ еffесts of nеiglrЬo dimеnsions' Ьut и align with thе oriс in individual Ьеha and floсks of Ьirdr

SсlсiаlBеhаuior апd S
UndеrlyingМесhanisms:From Hormonal Сontrol tо Sеlf-organization Dесisionrnаking undеrliеs thе еmегgеnсеof arrimal soсiеtiеs.Although сomparisonstrf сosts and bеnеfitsprovidе thе ultimatе ехplanation of whеn par. tiсulаг soсial variations аге fаvorеd Ьy sеlесtion, thе wаy irrformation is proсеssеdand usеd in making soсia1dесisiоns rеquirеs foсusing on a diffеrеnt lеvеlof anerlysis.In thе pаst, studiеsof sосiality foсusеd on only onе sсa|е: еithеrwhy individuаls intеraсtеdthе wаy thеy did or on how suсh Ьеhavior was triggеrеd.Morе rесеntly' studiеshavе Ьеgun moving aсross sсalеs,сomЬining thе two to providе а lтlorе intеgrаtеdundеrstаnding of thе сausеs of soсial Ьеhavior. onе form of intеgration ехaminеs how informаtiorr withir-rorganisms organizеsЬеhaviсlr.Sinсе nluсh of Ьеhavior is сonditioned on fеatrrrеsof thе physiсal or soсial еtrvironmеnt'еnsuring that appropriatе Ьеhaviors appеar at thе right timе, in thе right сOntеХt'and in thе prеsеnсеof thе right рartnеrs rеquirеsсoordination. Hormonеs arе сoоrdinators par еxсеllеnсе.\й/hеntwo animаis aге rеady t() ll1аtе' thеy mr-rstЬoth Ье in thе right mоod; whеn thеy matе,maturе gamеtеsmr"rstЬе rеаdy and waiting; and whеn thе agе oг sizе for thе trаnsition frсrmsuЬadult to rnaturе adult is rеaсhеd,many phenotypiс fеaturеsmrrst Ье rеorganizеd.\Хihiсh suЬstanсesсontrol what proсеssеsand whеthеr thеy aсt оrr thе Ьrain or othег organs сan vary' Ьut initiating and thеnсoordinating and intеgratirrgmany aspесtsof soсiаl bеhavior rеquiге information flow. Ultimatеlv thе proсеssеsinvolvеd сonstrain what Ьеhavior is possiЬlе. Arrothегtypе of irrtеgrationinvolvеs undеrstanding how сollесtivе Ьеhavior еmеrgеsfrom thе aсtions of individuals (Lеvin |999). Oftеn pattеrns ot bеhaviorviеwеd at onе sсаlе appeаr imposеd fгom aЬovе' whеrеas at аnothеr sсaiеthеy appеar to еmеrgе from Ьеlow as if sеlf.organized.Thus animals may assеrnblеin partiсuizrrhаЬitats Ьесausеof prеvaiiirrgеnvirontnеntalсonditions,Ьut whеthеr or not thеy form tightly knit groups of partiсular shapеs and sizеs dеpепds on how thеy intеraсt with еaсh othеr. Simplе rulеs of rеpulsion,attгасtion, and alignmеnt аssoсiatеdwith intеrасtion zonеs сan aссount for thе sizе, shapе, сomposition, and dirесtion of group movеmеnts. Using a sеt of hiеrirrсhiсаl dесision rules thаt Ьalanсеd repulsion to avoid сompеtition and attraсtion to rеduсе risks of prеdation, Guеron and сollеaguеs(I996) showеd that groups displayеd a widе variеty of shapеs and tеndеnсiеsto fragmеnt and sеlf-sort bv phеnotypе. All that wаs rеquirеd to induсе thеsе transitions was information aЬout thе spееd and position of сlosenеighЬors.Mrrсh dеpеndеdon thе ехistеnсеof а rrеutralzonе whеrе thе effесtsof nеighЬors did not altеr intrinsiс tеndеnсiеs.Similar models in thrее dimеnsions,Ьut whеrе thе pгеsеnсеof a nеutrаl zonе allowеd individuals to alignwith thе oriеntirtionof a nеаrеst nеighЬor, rеvеalеd how small сhangеs in individuаl Ьеhavior сould dramatiсally сhangе thе shapе of sсhools of fish and floсks of Ьirds (Сouzin аnd Krausе 2003). Dеpеnding on tlrе strеngth of

250

Soсiаl Bеhаuior апd Sociobiсllogу oriеntation, groups сould movе from disorganizеd swarms to highly polar. izеd сonformations. In faсt' strеngth of alignmеnt playеd a сritiсal rolе in undеrstanding lеadеrship, information transfеr' and сonsеnsus dесision making within groups еvеn whеn informеd individuals did not know thе quality of thеir information or whеthеr thеy wеrе in thе majority or minority (Сouzin еt al. 2005).

From Animals to Pеoplе Humans arе animals, so it sееms sеlf-еvidеntthat еvolutionary proсеssеs should shapе human soсiality. First prinсiplеs, еspесiallythosе that undеrliе thе synthеtiс modеl of soсiality in nonhuman animals, havе stimulatеd and organizеd thе study of human soсial Ьеhavior. Not surprisingly, сonnесtions among partiсular fеaturеs of soсial еvolution and partiсular aspесts of human naturе havе Ьееn idеntifiеd. Nowhеrе is this morе apparеnt thаn in thе arеa of matе сhoiсе. In rodеnts gеnеs assoсiatеd with thе majоr histoсompatibility сomplех (MHС) affесt сеll rесognition and immunе funсtion. During еstrus fеmalеs assoсiatе with malеs that diffеr gеnеtiсally from thеmsеlvеs' whеrеas whеn thеy arе prеgnаnt, thеy assoсiatе with fеmalеs that arе gеnеtiсally similar. Assеssmеntis via odor and suggеststhat MHС-speсifiс assoсiations arе еvolutionarily adaptivе. Divеrsifying thе genе pool of offspring should improvе thеir immunе funсtion, and assoсiating with сlosе kin during prеgnanсy should rеduсе сosts and inсrеasе Ьеnеfits assoсiatеd with soсiality .sfеdеkind (Pеnn and Potts 1999). Whеn and сollеaguеs(1995) pеrformеd a study to sее if human fеmalеs showеd similar sехual prеfеrеnсеs, hе found that womеn in thе fеrtilе phasе of thеir сyсlе idеntifiеd thе odor of T-shirts from malеs with whom thеy sharеd МHС gеnеsas lеss ..pleasant''than thosе of malеs with whom thеy sharеd fеwеr gеnеs. Apparеntly thе samе undеrlying forсеs and mесhanisms еmployеd Ьy animals may Ье opеrating in humans whеn it сomеs to сhoosing matеs. But Ьy no mеаns do thеsе rеsults dеmonstratе that proсеssеs that shapе thе soсiosеxual Ьеhavior of animals will nесеssarily shapе thе Ьеhavior of humans in similar ways. Unfortunatеly, thе links Ьеtwееn animals and pеoplе arе oftеn prеsеntеd as univеrsally truе whеn in faсt thеy show variation dеpеnding on thе naturе of sеlесtivе forсеs. By ignoring thе сontingеnсy of sеlесtion, сlaims of univеrsality of human soсial institutions and thеir immutaЬlе naturе arе likеly to Ье falsе. As many of thе ехamplеs of animal soсiality ехplorеd еаrliеr havе dеmonstratеd, partiсular typеs of soсial rеlationships and soсial systеms thrivе only undеr a limitеd sеt of еnvironmеntal сonditions. Why, thеn, should Wе еxpесt that only onе sеt of human rеlationships or only onе typе of soсiеty should еvolvе? It is somеwhat ironiс that politiсal thеory itsеlf is a human сonstruсt with еaсh prediсatеd on a diffеrеnt sеt of assumptionsaЬout human naturе. Сonsеrvativе philosophiеs oftеn dеpiсt humans as fundamеntally sеlfish, сompеtitivе, and somеwhat invariant, whilе morе liЬеral philоsophiеs oftеn assumе that humans arе flеxiЬlе and adaptablе.As is thе саsе with all animals, thеrе

is no onе animal grееs Ьy сoopеra thosе of most оt} and morе variеtiс diffusе. But this . not apply to thos nесеssarily invali< onе of thе mos сan ехplain a nс Ьrothеr's phеnorr posеd to thеir ov stratе8y appеars еqual, a parеnt sh as with a sibling's еspесially truе in (Flinn 1981; Iron riсh' and as a rеst raisе their сhildrе philandеring is hi is сommon' and l Еvеn if offspring i sister's сhildrеn tЬ ship thеory, mеn z thе Ьеst of a Ьad j

Applying соst.t man soсial Ьеhav biology sought to Ьеhavior of ехisti hopе was sеlесtiv that had opеratеd likеly to Ье truе' i for idеntifying h among and Ьеtwе most animal soсiе сlosеly to thеir еn aЬlеs сan Ье mеas Pеrhaps spurге psyсhologists аlso pеrspесtivе, but t sought to idеntify lutionary timе. Fo anisms thаt our ostraсizing сheats solvе suсh proЬlе сusеd on rеproduс mесhanisms that

So сiаI B еhаuior а пd Soсio biolсl91, z . \ I rganizеd swarms to highly polar]nmеntplayеd a сritiсal rolе in unеr, and сonsеnsus dесisiсlrrmaking Juals did not know thе quality of thе mаjority or minority (Сouzin

.idеnt thаt evolutionary Proсеssеs plеs,еspесiallythosе that undеrliе mаn animals' havе stimulatеd аnd v i o r .N o t s u r p r i s i п g l yс' o l ] n е с t i o n S tion and partiсular aspесts of huе is this morе apparеnt than in thе с i а t е dw i t h t h е m а j o r h i s t o с o m p a t tion and immunе funсtion. During diffеr gеnеtiсallу from thеmsеlvеs, soсiаtеwith fеmalеs that arе gеnеsuggеststhat МНС-spесifiс assoсi'sifying thе gеnе pool of offspring rd assoсiatingwith сlosе kin during sе Ьеnеfitsassoсiatеdwith soсiality and сollеaguеs(1995) pеrformеd a rnilar sехuаl prеfеrеnсеs' l.rеfound :yсlе idеntifiеd tlrе odor сlf T-shirts ..plеasant''than thosе ) gеnеsas lеss еnеs.Apparrntly thе samе undеrlyl animals may Ье opеrating in huBut bу no mеans do thеsе rеsults :lе soсiosеxualЬеhavior of arrimals rans in similar ways. Unfortunatеly, : oftеn Prеsеntеdas univеrsally truе ing on thе naturе of sеlесtivеforсеs. сlaims of univеrsalityof human sorrе arе likеly to Ье falsе. As many of Lеarliеrhavе dеrnonstrаtеd'partiсul systеmsthrivе only undеr a limitсd rеn,should We еХpесt that only onе .pеof soсiеtyshould еvo[vе? ory itsеlf is a human сonstruсt with mptions аЬout human naturе. Сonns аs fundamеntallysеlfish' сompеtrе liЬеral philosophiеs oftеn assumе As is thе сasе with all aniпrals, thеrе

is no onе animal naturе. Aggrеssion and dominanсе arе offsеt to varying dеgrееslry сooperation and altruism. What sеts human soсiеtiеs аpaгt from thosеof most оthеr animals is thеir сornplехity. Moге lеvеls of orgenizatiorr and morе variеtiеsof rеlationshipsсan form, thus making intеraсtions morе diffusе'But this doеs not mеan thе rulеs that struсturе animal soсiеtiеs do not apply to thosе of humans. Pеrhaps thеy arе insuffiсiеnt,Ьut thеу arе not nесеssarilyinvalid. onе of thе most сompеlling ехamplеs whеrе еvolutionаry гulеs of soсiality сan ехplain а novеl sеt of human rеlаrionships is thе so_сallеd mothеr's brothеr'sphеnomеnon, in whiсh mеn invеst in thеir sistеrs' сhildrеn as opposеd to thеir own сhildrеn (Alеxandеr 1979a, 1979ь)' At first glalrсе this stratеgyappears to violatе thе most Ьаsiс rulеs сlf kinship. All еlsе Ьеing еqual,a parеnt sharеson аvеragеtwiсе as many gеnеswith its own offspring as with a siЬling'soffspring. But in somе soсiеtiеsntlt all еlsе is еqual. This is .Wеst espесially truе in marry Afriсan soсiеtiеs, suсh as that of tlrе Tongir (Flinn 1981; Irons 1981). Thе land upon whiсh thеsе hortiсulturalists livе is riсh, and as a rеsult, fеmalеsсаn dеrivе еnough rеsourсеsfrom thеir laЬor to raisеthеir сhildгеn witlrout thе aid of thеir husЬаrrds.In suсh сulturеs fеmalе philandеringis high' and fеmalеs сan initiatе divorсе. As a rеsult, сuсkoldry is сommon' and mеn arе not likеly to Ье fathегs of thеir putativе сlrildrеn. Еvеn if offsprir.rgarе only half siЬs, mеn will Ье mоrе сlosеly rеlatеd to thеir sistеr'sсhildren than to thеir own pцtativе offspring. Thus, aссording to kinship tЬеory,mеn аrе Ьеhavingеvolutiоnаrily rationаlly sinсе thеy arе making thе bеst of a Ьаd job and invеsting in thе сlosеstgеnеtiс rеlаtivе аvаilaЬlе. Applying сost-Ьеnеfitand gеnе-aссountingprinсiplеs to thе study of hu_ mаn soсiаl Ьеhаvior is thе сornеrstonеof soсioЬiology. Мuсh of еаrly soсiobioiogy sought to ехplain humar"rity's soсial roots аnd thus studiеd thе soсial Ьеhaviorof ехisting сultures minimally impaсtеd Ьy lrVеstеrnsoсiеtiеs.Thе hopе was sеlесtivеprеssurеsthat сurrеntl1,opеratеd Wеrе thе sаmе as thosе that had opеratеd in tlrе past. Although thе assumption of сontinuitv is unlikеly tо bе truе, it doеs not invаlidatе thе undеrlying soсioЬiologiсаl sеarсh for idеntifying how еnvironmеntal prеssurеs shapе htrnran rеlatitllrships among and Ьеtwееn sехеs and within and Ьеtwееn familiеs' Morеovеr, аs irr most animal soсiеtiеs,individuals in thеsе non-!Иеstеrnizеdsoсiеtiеsarе tiеd сiosеlyto thеir еnvironпrеnt.Тhus есоlogiсаl, soсial, аnd геpгodr-rсtivе vаriaЬlеsсan Ье пrеasurеdto idеntify pattеrns of саusаtion. Регhaps spurrеd on Ьy thе Darwinian invеstigation of human soсiality, psyсholоgistsaiso Ьеgaп ехаnrirringhunrаn soсial Ьеhavior from an аdaptivе pеrspесtivе'Ьut thеir approaсh was fundamеntally diffеrеnt Ьесausе thеу soughtto idеntify how natural sеlесtionshapеd thе human psyсhе Ovеr еvolutionarytiпrе. For psyсhologists,thе r.rltimatеquеstion wаs, ,.Arе thе mесhаnisnrsthat our Ьrains usе to makе dесisions aЬout сhoosing lnatеs or ostraсizingсhеats thе onеs that wе woulс] ехpесt if thеy wеrе .dеsignеd' to s o l v еs u с h p r o Ь l е m s ? ' ' ( B a r r е t tе t a l . 2 0 0 2 ) . T h u s w h i l е s o с i o Ь i o l o g i s t sf с l сusеdon rеpгoduсtivеoutсomеSto mеasurеadaptation and oftеn igrrorеdthе mесhаnismsthat undеrliе assеssmеnt and dесision making' еvolutionary

2.'2

Sociаl Bеhаuior апd Soсiobiologу psyсhologists foсusеd on idеntifying tlrе mесhanisms of assеssllеnt аnd information proсеssing with littlе геgard for rеproduсtivе ouссomеs. Just as an intеgratеd approасh tсl thе study of soсial Ьеhavior has еmеrged withirr thе biologiсal tradition' аn approaсh that intеgratеsmесhanistiс and funсtional quеsts for undеrstandingthе zrdаptivеvaluе of thе hurnan mind аnd thе roiе it plays in shaping soсial Ьеhavior would Ье thе Ьеst of Ьoth worlds. It would сut aсross sсalеs and pгovidе nrоrе сonrplеtе insights ilrto whу humаns Ьehavе thе way thеy do. Although humans аrе animals, thеy arе еХсеptionalanimals in many ways. The languаgе thеy usе is morе сomplех thаn tlrе сommuniсation systеmsof othеr animals; thе ways in whiсh thеy manipulatе and dесеivе :rnd givе support to аnd еliсit it from othеrs arе morе suЬtlе than in any othеr spесiеs;ernd oniy humans havе dеvеlopеd сultural noгms and trаditions thаt сan Ье nrodifiеd and passеd on t
Barrеtt,L., R. DunЬar,аni Prinсеton,NJ: Рrinсеt Batепаn,A. J. 1948.Irrtra .W., and S. L. BradЬury'J. i n е m Ь а l l o n u r iЬ dаts 2: 1-17. 1977ь.Soсiаlorgа pattеrns.B invеstmеnt Сlutton-Broсk,Т. H., P. N I,. Sharpе,R. Kanskу to ЬaЬv сontriЬutions Proсее,!iпgsof thе Rс Сlutton-Broсk,T. H., A. F G' M. MсIlrath.200 ir'еЬеhlviогi сoopеr:tt С o u z i n 'I . D . , a n d . | .K r а u Аduапсe vеrtеЬratеs. Сouzirr,I. D.' J. Krаusе,N а n dd е с i s i о rnn а k i п ig Сrееl, S. R., and P. М. Wа (НеlogаI пlonЕ]oosеs 2:7-15. Сrook, J. H. 1964a'Thе е in thе wеаvеrЬirds(P 1964ь.Fiеldехрс с е r t а i nw с a v е rh i r d s 2 1 7 - 2 55 . D:rrvkins'k. 1'976.Thе Sе Еmlеn, S. T. l99.5.An сvo NаtiсlпаlАсаdеmуof 1 9 9 7 .P r е d i с т i nf N. B. Dаviеs,еds.,Bс o х Г o r d :t s l а с k w е5l lс Еmlеrr,S. T.' and L. W. o Sсlcr nratingsуstепrs. Еmlеn, S. T., and P. tl. w of hеlpеrsаmongbее FаaЬorg,J., P. G. Parkеr, Naranjo,аnd T. A. $ GalapagosHawk 1Bи

Ес.l/.,дl'а пd S,'..i.ll,i, F l i n n , М . 1 9 8 1 . U t е r i n еv marriagе prеfеrеnсе апd Г). W. Tinklе, еd апd Nеьu Theorу', 4З -l Friсkе, H. W' 975. Еr,ol Zсitsсhrift fйr Tiеrps Gross, M. R., and Е. I-.С sunfish. Proсееdiпgs G u е r t l n ' S ' . s . А . l . с v i n .; h е r d s :F г o m i n d i v i d r 85-98. Наmilton, \и. D. 1964. T of ТЬ еl lrеtiсаI В tсlhli

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mесhanismsof assеssmеntand in. rеprоduсtivеOutсomеs. Just as an l Ьеhаvior has еmеrgеd withirr thе еgratеsmeсhanistiс аnd funсtional uе of thе human mind and thе rolе )е thе bеstсlf Ьoth worlds. It would llеtеinsightsinto why humans Ьеехсеptionalanimals in many ways. han thе сommuniсation systеms of rnipulatеand dесеivе and givе supuЬtlе thаn in any othеr spесiеs; and rnsand traditiotlsthаt сan Ье modэrrary rulеs will havе rnuсh to say ors. And whilе wе sеarсh 1Ъr |inks )artiсularсirсumstanсеs,wе should t might undеrliеthе organization of lеd into сollесtivеsсomposеd of inphеnotypiсally. Pеrhaps this is Ьеd rеpеatеd intеraсtions strеngthеn or individualsto assoсiatеwith oth.l soсietiеsas thеy gеt largег (RuЬеnnеnts will сontinuе to favor сеrtain LаritywiIl rеduсеunсеrtaintyand inе r l l е rЬ a s е do n а l t r u i s m .r е с i p r o с i t y , ; a tool that humans usе to rеinforсе d to Ьroаdсastthе еxploits of сoopI Riсhard Dawkins (7976)-сan Ье ,еnеs,with good orrеs sprеading and oсial norms that ехtol virtr.rеmay Ье :ntiatеshumans from most othег sosеntialif wе arе еvеr to know what :iеs,Ьut it will bе madе virtually imrgеndas.

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255

Human Еvolution Непrу Iv4.NIсIfеnrу

Тlrе riсhnеss of thе human fossil rесord аllows rеasonaЬlе сonfidеnсеin rесonstruсting <.lur еvolutiсlnaryhistory' This rесord dеmonstrаtеsthat humаn. like forms appеaгеd Ьy aЬout 6 million yеars ago and aссumulatеd morе atrd morе human сhаraсtеristiсsthrough timе. As Darwin and his сontеmporагiеs prеdiсtеd, thе human linеagе shows сlеаr еvidеnсе of dеsсеntwith modifiсation. Pеrhаps thе Ьеst dеmonstrаtion of tlris is thе еxpansion of thе Ьrain through timе (TaЬlе 1)' Fossil spесiеs that wеrе сlеarly humanlikе in Ьody and dеrrtition 6 to 3 million yеars ago had аpе-sizеd br:rinsthat Wеrе orrе-thirdthе sizе of thosе of nrodеrn lrumans.Just aftеr 2 rlillion yеarsago somе fossils show an inсrеasе to aЬout half thе sizе of Homo sаpiепs, and ovеr thе pаst half million yеars, modеr:rrЬrаin sizе appеаrs in thе fossil rесord (Сonroу 200.5; Sсhwi1rtz and Tаttеrsall 2002, 200з, 2005; Dеlson еt al. 2000). Although Darwin аnd othеr еarly еvolutionists wеrе kееnly interеstеdin h u n l . r nе v o l u r i o n а n d n l a d е g , г е а rs t r i d е s i r l i n t е r p r е t i n 8с o m p а r а t i v еm o r phology fгom an еvсllutionarypoint of viеw, vеry fеw prеmodеrn humаn fossils werе known in thеir day (Huxlеy 1863). By thе turn оf thе twеntiеth сеntury' Ьits оf Nеandеrtals аnd ..Java п1аn'' еntеrеd thе сonsсiousnеssof еvolutionary Ьiologists (Kеith 1915). B1,thе turn of thе twеtltу-firstсеntury' thousands of prеmodеrn fossils had found thеir wаy into thе world's musеums, and knowlеdgе of humаn еvolutiorl had grown spесtaсularly (Dеlson е t а l . 2 0 0 0 : С o n r o y 2 0 0 5 ; K l е i n 1 9 9 9 ; S с h w a r t z i r n d T a t t е r s a l l2 0 0 2 ' 2 0 0 з ' 2005; Holloway еt aL.2004). Thе riсhnеss of thе rесord is duе to thе intеlligеnсе' skill, zrnddiligеrrсеof thе fiеldwсlrkеrswho find thе fossils and dеtеr. minе tlrеil Ьiologiсаl and gеоlogiсal сoIrtеxts.

our Plaсе in Naturе It was сlеar to Dаrwin and his сontеmporariеsthat pеoplе sh:.rrеd a сommon anсеstor with living apеs morе сlosеly thzrnwith any othег anirnal' Thomas Huхlеy (1863) Was a partiсularly strong advoсatе ftlr an apеlikе anсеstryof 256

thе human linе, aп forms from apеlikt Сuriouslу, thеir lеngеd during thе lеngеs inсludеd th. animal world rеsе 1926,1929). Othr сommon anсеstor ..prе-apе'' kind of i n g a p е s ( е . g . ,N a p so divеrgеnt in sh gеnсе of thе humz Thе ninеtееnth-се (е.g.,Grеgorу 1'9| until thе last thrе lonеly voiсеs (Flеa

Among thе man tionary studiеs du appliсation of moi сomparing thе str protеins of аnothе tiс rеlatеdnеssam( to most сomparati timе, humans Wеt than Afriсan apеs wеrе far morе dist .\X/ils (Sariсh and firmеd thеsе еarly (е.g., alЬunrin) wl 1,967).Сonstanсy lutionary linеagеs divеrgеnсе and thr Sariсh and.Wilsorl of sеvеral mamm From this thеy сa mans and Afriсan finеmеnts plaсе th сurrеnt еstimatеs( 1989; Chеn and L tеrson еt a|' 2О06 thе advеnt of DNl latеd to thе Afriса ary linеagеs is rеlа A sесond impor thе mеthods of с сannot Ье appliе

Hцmап Еuolutioп

n

lows rеasonaЬlесonfidеnсе in rеrесord dеmonstratеsthat humаn/еars ago and aссumulatеd morе r i m е .A s D a r w i n a n d h i s с o n t е m ws сlеar еvidеnсеof dеsсеnt with ion of this is thе ехpansion of thе еs that wеrе сlеarly humanlikе in 3o had apе-sizеdbrains that wеrе ans.Just aftеr2 million yеars ago rlf thе sizе of Homo sаpiепs, and L Ьrain sizе appеars in thе fossil е r s a l l2 0 0 2 , 2 0 0 3 , 2 0 0 5 ; D е l s o n rtionistswеrе kееnly intеrеstеd in i n i n t е r p r е t i n gс o m p а r а t i v е m o г v' vеry fеw prеmodеrn human fos63). By thе turn of thе twеntiеth tan'' еntеrеdthе сonsсiousnеss of lе turn of thе twеnty-first сеntury, l thеir way into thе world's musеhad grown spесtaсularly (Dеlson 7wartzand Tattеrsa||2002. 2ooЗ. ; of thе rесord is duе to thе intеlli. еrs who find thе fossils and dеtеr\LS.

rriеsthat pеoplе sharеd a сommon rn with any othеr animal. Thomas Ldvoсatеfor an apеlikе anсеstry of

thе human linе, and Haесkеl (1s6s) imaginеd and namеd a spесifiс sеriеs of forms from apеlikе to humanlikе. Сuriously, thеir apе-man thеory (as it was latеr сallеd) was sеriously сhallеngеd during thе first sеvеn dесadеs of thе twеntiеth сеntury. Thеsе сhallеngеs inсludеd thе viеw thаt thе last сommon anсеStor wе sharеd with thе animal world rеsеmЬlеdthе tarsiеr morе сlosеly than any apе (Jonеs 1918, |926, |929). other еarly twеntiеth-сеnqurysсiеntistsrесonstruсtеdthе last сommon anсеstor as morе monkеylikе than apеlikе (Straus 1949) or as somе ..prе-apе''without long fingеrsand uppеr.Ьody spесializationsof livkind of ing apеs (е.g.,Napiеr and Davis 7959I. Bесausеmodеrn humans appеar to bе so divеrgеnt in shapе and bеhavior from othеr аnimals, thе timе of divеrgеnсе of thе human еvolutionary linеagе was oftеn givеn as quitе anсiеnt. ..apе.man'' thеоry сontinuеd to havе sцpPortеrs Thе ninеtееnth-сеntury (е.g.,Grеgorу \9 |6, 1926, 7927a, 1927ь, 1'928,19З 41 sИashЬurn1 95 1 ), Ьut until thе last thrее dесadеs of thе twеntiеth сentuгy thеsе wеrе rеlativеly lonеly voiсеs (Flеaglе and Jungеrs 1982). Among thе many important сhangеs in viеw and mеthod in human еvolutionary studiеs during thе last fеw dесadеs of thе twеntiеth сеntury was thе appliсatiоn of molесular Ьiology. Immunology providеd thе first insight. By сomparing thе strеngth of thе immunе systеm,s rеsponsе Ьy onе spесiеs to proteinsof anothеr spесiеs,Goodman (1963\ quantifiеd an еstimatеof gеnеtiс rеlatеdnеssamong primatе spесiеs. Thе rеsults wеrе shoсking at thе timе to most сomparativе anatomists.Contrary to prеvailing undеrstandingat thе timе, humans wеrе morе similar to Afriсan apеs (сhimpanzее and gorilla) than Afriсan apеs Wеrе to thе Asian grеat аpе (orangutan). Monkеy spесiеs wеrе far morе distantly rеlatеd. Morе sophistiсatеdimmunologiсal mеthods (Sariсhand.!Иilson 1966) and DNA hyЬridization (Hoyеr et a|'.1964) confirmеd thеsе еarly rеsults and rеvеalеd that сhangеs in somе maсromolесulеs .Wilson (е.g.,alЬumin) wеrе rеlativеly сonstant through timе (Sariсh and 1967).Сonstanсy of сhangе pеrmittеd еstimatеsof timе of divеrgеnсеof еvolutionary linеagеsas long аs thе ratе сould Ье сaliЬratеd Ьy a known datе of ..molесularсloсk.'' divеrgеnсеand thus providе a Ьasis for dеvеlopmеntof a 'Wilson (\967) usеd thе datе of 60 million yеars for thе divеrgеnсе Sariсhand of sеvеral mammalian ordеrs to сalсulatе thе ratе of сhangе in alЬumin. From this thеy сalсulatеd that thе divеrgеnсе of thе linеagеs that lеd to humans and Afriсan grеat аpеs oссurrеd 4.2 million yеаrs ago. SuЬsеquеntrеfinеmеntsplaсе thе datе somеwhеrе Ьеtwееn 10 and 5 million yеars Ьy most сurrеntеstimatеs(Kumar and Hеdgеs 1998; Kumar еt al. 2005; Holmеs еt al. 1989;Сhеn and Li 2001; Arnason еt al. 2000; PilЬеam and Young 2004;Pattеrsonеt a|.2006; Glazko and Маsatoshi 2003; Stauffеr еt al.200]). !7ith thе advеnt of DNA sеquеnсing it is now сlеar that humans arе vеry сlosеly rеlatеdto thе Afriсаn grеat apеs)and thе timе of divеrgеnсеof thеir еvolution. ary linеagеsis rеlativеly short from thе pеrspесtivеof mammаlian еvolution. A sесond important сhangе in thе latеr pаrt of thе twеntiеth сеntury was in thе mеthods of сomparing morphology of spесiеs. Molесular approaсhеs сannot Ье appliеd to fossiis muсh oldеr than 70'000 yеars (Krausе еt al.

257

ТаЬlе 1. Speсiеs,datеs,Ьody size, Ьrain sizе,аnd postеrioгtootЬ sizе in еarly hominids Мassз Taхonl

Рап troglodуtes Sаhеlапthropus tсhаdeпsts Оrroriп tugeпепsis Ardip itb eсus kаdа|э|эа А u strаlop i tll есus апаmепsis A ust rа l op it h t'сиs а[аr еnsi s Аus trаlop it ll еcus аfri саnus Pаrаnthropus аethiop iсus Pаrапthropus boisеi Pаrаnthr opиs rt:lbustus Aиstrаlopitbeспs gаrbi Hrllllo Ьаbilis Hсlmo rudolfeпsis Homo ergаstеr Homo ereсtus

Datеs2

Ma1е

Fеmalе

Еxtant 7-6 6 5.2-5.8

49

41,

4.z_З.9 3.9-3.0 З.0_2.4 1-7

Horпo bеidelЬеrgeпsis Late H omo nе.lпdеrtb.llепsis

Homo floresieпsis Homo sаpieпs

0.09-0.01 Ехtant

Brain wеight6

З95 lJl

зЗ 29 30

151 1З8

й 115

1з7 132

r24 110

131 160 180

100 150 160

11

2'З_I.4 1.9-1.4 2.57.9-r.6 2.4-1.6 1.9-1.7 1.1-0.01 o.6-0.2 o-2-o.o3

ЕсV5

З65

;

+l

; 45 4l

Staгurеa Fеmalе

Mаlе

49

t+

40

.)z

-)/ 60 66 66

; 51 56 56

77 77

56 66

,t o. -/

.l

58

29 49

775

t06 t61

58

4; 452 41О 521 530 4s0 612 752 871. I,050 1,\94 7,414

380

4; 448 4О7 514 523 446 601 7з6 849 1,01.9 \,156 7.з62

з78 1'350

Postсanine tooth arеa7

294 329 .)Ч/ 428 460 516 688 756 588

ЕQ'

MQ,

:Y 2..4 2.7

1.7 2.О

2.7 3.0

2.7 2.2

389 33-5

з.6 -1.1 3.З 4.0 4.2 4.7

1.9 1.5 0.9 1.0 0.9 0.7

ЗЗ4

2.6 5.8

1.8 0.9

478 572 - ) // 402

1. Taхtlnomr,Ьаsеdon Klеin (1999)rvitЬ аdditionsfrom Brunеt еt al. (2002),Sеnutеt al. (2001)'Brown еt al. (2004),and HаiIе-Sе|assiе еt аl. (2004). 2. Dаtеs (in millions of yе:rrsаgо) аrе from Кlеin \1999)' wiгh аdditionsfrorn Brunеtеt al. (2002),Sеnutеt аl. (2001),Br
s Aи strа l op it h есus апаmeп.si Аustrаlop itheсus аfаrеnыs Аиstr аlop itheсus аfr i сапus Раrапthrсlpиsаеthiop iсus Pаrапthropиs boisei Pаrапthropus robustus Аustr аlop ithесus gаrhi Homo hаbilis Homo rudolfепsis Homo еrgаster Homo еrectus Homo hеidelbеrgensis Late Homo neапdertbаlеnsis

Нomo Homo

floresiепsis sсIpieпs

4.2-3.9 3.9-3.0 3.0-2.4 2.7-2.2 2.3-1.4 1.9-1.4 2.5-?

1.9-r.6 2.4-1.6 r.9-r.7 1.1-0.01 0.6-0.2 0.2-0.03

0.09-0.01 Еxtant

51 45 41 49 40 -)/ 6О 66 66 77 77

58

JJ

29 30

; 138

r*

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124 110

; 160 180

100 150 160

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106 16,|'

+L6

4З8 452 410 52L 530 450 612 752 871. 1,050 1,194 1,414

4З4 448 407 5\4 52з 446 6О1 7з6 849 1,01,9 1,156 1.,362

3B0

З78 1,350

l.a

460 516 688 756 s88

2.4 2.7

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478 572 З77 402 З89 335

з.6 3.1 3.3 4.0 4.2 4.7

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еt аl. (2004). 1. TaxtlnсlmyЬаsеdon Klеin (1999)with аdditionsfronr Brunеt еt al. (2002),Sеnutеt аl. (2001),Brown еt al. (2004)'and Hailе-Sеlаssiе 2. l)atеs (in milliсlns
260

Humап Еuolutiсlп 2О071Оr|ando еt аl. 2006), so morphology is thе only guidе tсl undеrstanding rеlationships.Сlosе еvolutionary rеlationshipsсan Ье infеrrеd from similarity in morphology (sее Figurе 1)' Ьut not withоut сarеful analysisof thе сausеs of rеsеmЬlanсеs.Еvolutionary Ьiologists havе always Ьееn awarеof this, of сoursе, Ьut a formal approaсh to makе сomparisons of form only took hold in thе latеr part of thе twеntiеth сеntury. Willi Hеnnig (I966) formalizеd thе approaсh to сomparing morphologyof spесiеs Ьy noting that rеsеmЬlanсе of form did not nесеssarily imply сlosе phylogеnеtiс affinity. Similaгity may Ье duе to sharing primitivе сhаraсtеriу tiсs that arе not hеlpful in dеtеrmining Ьiologiсal rеlationships.Aspeсtsof thе dеntition of thе 28-million-yеar.ol d Propliopitbесus, for ехamplе, rеsеmЬlе thosе of modеrn humans morе than thosе of modеrn apеs (Kurtеn 1972), but thеsе arе duе to thе rеtеntiсlnof anсеstraltraits and not to thе еvolution of uniquе traits sharеd only Ьy dеsсendantsand not presеnt in othеr сlosеly rеlatеd spесiеs.Somеtimеs similaritiеs аrе duе to parallеl or сonvеrgеntеvO. lution rathеr than dеsсеntfrom a сommon anсеstor.Thе wings of Ьirds'Ьaв, and Ьuttеrfliеs arе similar, Ьut not Ьесаusе thеy еvolvеd from thе samе wingеd anсеstor. Thе tеrm homoplаsу is usеd to dеsсriЬе thе phеnomеnon whеrе organisms sharе uniquе traits that еvolvеd indеpеndеntlyin sеparatе

linеs of dеsсеnt. F 1996). Bесausе Hеl ary divеrgenсе, it is is а uniquе еvolutiс traits that arе not sharеd uniquе tra ..sharеd dеrivеd.'' Тhе powеr of th hеlps rесonсilе thе thе fossil rесord. As now rеflесt our truе (orangutans, gorillz mans into Hominiс that rесognizеs thе сladе as thе family familiеs Gorillinaе mans). It is a usеfu organiс forms and t

Bеforе Hominir ll0mo

еreстus {n'.,,./

r"l

(flakedstonе агtifаds unknown)

б--\ Sahelanthropus tсhadensis

Figurе 1. A working hypothеsisof еvolutionаryrеlationshipswithin thе human fossil rесord,rеdrawn from R. G. Klеin.

our сlosе gеnеtiс r origin of our еvolul natеly, thе fossil rе panzееs' and humar bеttеr known. Disсr rеvеaling. In sеdimе forms appеar that ] (Pilbеam 1982). Siu uniquеly orang-likе profilе of thе faсе Ьt fеaturеs that among Thе faсе of thе As thе Afriсan сladе (g of thеsе living spес may not' Ьy thе logi, Мost palеontologis qualify Еuropеan f. ago), ourапopitbес, (1'2.5_|З million yе as part of thе Afriса Afriсa for ]\4ioсеnе sparsе' but diligеnt pitheсus (16 to 14 r 15 million yеaгs ago

Нumаn Еuolution 4y is thе only guidе to undеrstarrdionshipsсan Ье infеrrеd from simi.rotwitlrotrt сarеful arralysis of tlrе logistshаvе alwaУs Ьееn awarе of l makе сomparisorrsof form only 1 сеntЦry. roaсh to сomparing morphology of гrr-r did not nесеssarily imply сlosе uе to sharing priпritivе сharaсtеrisliologiсal геlationships.Aspесts of "oРlioРithеcus, for ехamplе' rеsеm.osеof nrodеrn apеs (Kurtеn 1972), stral trаits and not to thе еvolrrtion lts and not prеsеnt in othеr сlosеly : duе to parallеl or сonvеrgеnt еvol аnсеstoг.Thе wings of Ьirds' Ьаts, ausr thеy еvolvеd from thе s:rmе usеd to dеsсribеthе phеnomеnon е v o l v е di n d е p е n d е n t l yi n s е p a r a t е

ll0mo f/oresiensь р1"

la

Artifaсt Тraditions Д,t". st"'* дg" а

Г.

J Upper PaIeo|ithiс пn(........м iddle stone Age & [ )i \Дj!g]g|g!gg]Щi.

ff::Б'|'

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within thе humаn nary rеlаtionships

linеs of dеsсеnt. Homoplasy is pеrvasivе in human еvolution (МсHеnry 1996|.Becausе Hеnnig's mеthod foсusеs on thе сharaсtеristiсs of еvolutionary divеrgеnсе, it is oftеn rеfеrrеd to as сlаdistiсs' А сlаdе in this voсaЬulary is a uniquе еvolutionary Ьranсh оf thе trее of lifе dе6nеd Ьy shаring uniquе traits that arе not shаrеd in сlosеly rеlatеd Ьranсhеs. Неnnig сallеd suсh sharеd uniquе traits ..synapomorphiеs,'' whiсh is usually translatеd as ..sharеd dеrivеd.'' Thе powеr of this logiс pегvаdеs еvolutionary Ьiology (Hull 1988) and hеlps rесonсilе thе findings of molесular Ьiology with thе intеrprеtаtion of thе fossil rесord. As a rеsult, thе tеrms usеd to сlassify our biologiсal rеlativеs now rеflесt our truе gеnеtiс rеlationships. Thе old tradition plaсеd grеat apеs (orangutans'gorillas, and сhimpanzееs) into thе family Pongidaе and humans into Нon-rirridaе'but thе tгuе gеnеtiс affinitiеs forсе a rесlassifiсation that rесognizеs thе Asian grеat apе as thе family Pongidaе and thе Afriсan сladе as thе family Hominidае. \Х/ithin thе family Honrinidaе arе thе suЬ. familiеs Gоrillinaе (gorilla), Paninaе (сhimpanzее), and Homininaе (humans).It is a usеful rеmindеr that wе arе tightly nеstеd in thе ЬLrshof lifе's oгganiсforms and that thе origin of our uniquе linеagе is vеry rесеnt.

BеforеHоminins our сlosе gеnеtiс rеlationship to thе Afriсan grеat apеs impliеs an Afriсan origin of our еvolutionary linеagе. Fossil disсovеriеsсonfirm this. Unfortunatеly' thе fossil гесord of thе origin of thе Afriсan сladе (gorillаs, сhimpanzееs'and hunrans)is poorly doсumеntеd.Thе Asian сladе of our family is Ьеttеrknown. Disсovеriеs in thе foothills of thе Himalаyas arе partiсularly rеvеaling.In sеdimеntsthat datе Ьеtwееn aЬout 12 and 8 million yеars ago' forms appеar thаt rеsеmЬlе tlrе ofangutan in mаny spесifiс faсial fеaturеs (PilЬеam 1982|. Siuаpithеcus is thе gеnus namе that inсludеs fossils with thе uniquеly orang-likе fеaturеs of narrow spirсе Ьеtwееn thе еyеs, ..prowlikе', profilеof thе faсе Ьеlow thе nosе' сonstruсtion of thе palаtе, and matly othеr fеatuгеsthat among thе living spесiеs oссur in thе оrаnguta n (Pongсt)' Thе faсе of thе Asian сIade (Siuаpitheсlts and Poпgсl|сontrasts with that of thе Afriсan сladе (gоrillas,сhimpanzееs,and humans), Ьut thе rеsеmЬlanсе of thеsе living spесiеs may Ье duе to sharing primitivе сharaсtеristiсs and may not' Ьy thе logiс of сladistiсs,Ье usеful in dеtеrminingtruе rеlationships. Мost palеontologists aссеpt thеsе rеsеmЬlаnсеs as suffiсiеntly r"rniquеto qualify Еuropеan fossil gеnегa suсh as Drуopithесus (8_13 million yеaгs ago),Ourаnopitheсus (9_10 million yеars ago), and pеrhaps Piеrolаpitheсиs (12.5-1Зmillion yеars ago) (Moyi-Soli et a|' 2004; Bеgurl and rwаrd 2005) as part of thе Afriсan сladе (Bеgun 1994;F|eag|e 1999). Thе fossil rесord in Afriсa for Мioсеnе mеmЬеrs of Hominidaе (Afriсan apеs and humans) is sparsе' Ьut diligеnt attеmpts сontinuе to promisе nеw disсovеries' Кenуа. pitbесus(16 to 74 million yеaгs ago) and rеlatеd gеnеra (Еquаtoriиs, 16 to i5 million yеars ago) appеar to Ье part of thе Afriсan сladе with living nrеm-

261

262

Humаn Еuсlllttioп bеrs, Ьut еaсh has its own spесializationsthat mаkе thеm lеss attrасtivеas сandidаtеs for anсеstry of livirrg spесiеsof Нominidае (МсСrossin and BеnеЕt 1997\. T.hе palеoеnvironmеntwithin whiсh our аnсеstorsеvolvеd was influеnсеd profoundlу Ьy drаmatiс fluсtuationsirr world сlimatеs ovеr thе past 7 millioп yеars (VrЬa et a|. 19951Bromagе and Sсhгеnk 1999; Potts 2007; Piсkford 2006; Bеhrеnsmеyеr2006).Intеnsеpеriods of сold tеmpеraturеsin highlati. tudеs rеsultеdin еpisodеsof drought in thе tropiсs' Thesе appеаrеd:rt16_13' 6.5-5, аnd 2.8 million yеars ago' and Ьеginning at 2.5 million yеars ago' thе еarth еХpеriеnсеd21 сyсlеs of glaсiation in highеr еlеvations and lаtitudеs aссompaniеd Ьy rеduсtion in rainfall in еquatorial lands, еspесiallyAfriсa. HaЬitats fаvorеd Ьy hominids (anсеstorsof thе Afriсan apеs and humans) сontraсtеd and еxpandеd. Thе fossil rесord of hominids in thе Мiddlе аnd Latе Мioсеnе is frustratingly inсomplеtе, and almost nothing is known of thе linеagеs thаt lеd to сhimpanzееs and gorillas. Suгprisingly, muсh more is known of thе fossil rесord of our own Ьrаnсh, thе Homininaе.

Thе Еarliеst Hominins Rесogr-ritionof thе еаrliеr mепrЬеrsof Homirrinaе is guidеd by undегstanding gainеd from molесtrlаr Ьiology and сladistiсs.Thе molесular сloсk Ьraсkets thе гimе of divеrgеnсе somеwhеге Ьеtwееn 10 and .5 million yеars Ьy most сuгrеnt еstimatеs.By thе logiс of сladistiсs, thе еarliеst aпсеstor of humans сan Ье rесognizеd Ьy thе prеsеnсеof traits uniquе to thе linеagе.This is obvious Ьut is еasily сonfusеd Ьy naivе viеws of prе-Hеnnigiаn сomparativе morphology that сontinuе to plaguе human еvolutionary studiеs.If it looks .W.е now likе an apе' it is not nесеssаrily ехсludеd from thе human rеalm. sеrесord of an apеlikе-Ьесoming-lrumanlikе know оf аn ехtraordinary quеnсе of fossils.Thе еarliеstmеmЬеr of this sеquеnсеloсlks vеry apеlikе.By сlаdistiс logiс, that is ехaсtly what onе would ехpесt. Thе еarliеst сandidatе for mеmЬеrship in thе suЬfarrrily Hoпlininaе Ь Sаhеlаnthropus tсhаdепsis (Brunеt et a\. 2002). This prесious fossil skull frorrr Сhad was found in sеdirnеntsthat сontilinеd fаuna linkеd with datablе sеdimеnts in Еthiopia аnd North Afriсa 7 to 6 million yеars ago. Its ovеrall appеaranсе is quitе apеlikе' inсluding an еstimatеdЬrain sizе slightly Ьеlow thе avеrаgеfor living сhimpanzееs (TaЬlе 1). But Ьy thе logiс of сlаdistiсs,it sharеswith latеr hominins uniquе tгaits that dеfinе our linеagе.Thе mostimpoгtant of thеsе is thе сanir-rеthat, unlikе that of аpеs and primatеs in gеnеrаl, doеs not projесt or wеar against its lowеr prеmolar. This is a signifiсant fеaturе thаt wаs rесognizеd as an important diffеrеnсе Ьеtwееn apеs and pеoplе Ьy many, inсlшding Darwin \|872\. Small саninеs arе signifiсant.Darwin (|872) notеd that whеn human аn. сеstors first stood еrесt' thеy frееd thеir hands and сould Ьrandish wеаpоns foг thrеat аnd fight, thus no longеr rеlying
for sеlесtion that favс g е r s .A n о r h е г h o m i n i of thе forаmеn lltag howеvеr, Sаbelапtbrс t h е h u m а n l i n е a g е .I г mans. It has еnormou аpеs or еarliеr mеmЬ' having Ьееn Iеssdеvе Тhе disсovеrу of Sа n е s so f М i с h е l B r u n е t Chadian studеnt who Afriсan Rift, whеrе а minds us to Ье mind{l Almost all of thе .

сomes from thе Afri' еvеnts'many lаtе Мi< mеnts layеrеd Ьy volс. nаrurally oссurгingp< of ash in Еthiopia, K thе еarly part of thе s oссurrеd. Thе fiгst сhaptеr in to just lеss than 6 mill 2001; Piсkford et a|,2 this spесiеs сomЬinеd ' appеar to Ье adaprеd J u n g е r s2 0 0 8 ) . Slightly latеr in tim Еthiopian spесimеns rt Gabriеl еt a|.200l; H with Оrroriп tugепепs most rеspесts,Ьut it dс thеsе is а сaninе tooth sil or modеrn apеs anс the ability to hypеrеxtt It livеd in a сlosеd woс

Austrаlopithecus i 4.2-2.5 Nlillion Y

Тhе fоssil еvidеnсе fо Sаh еlапt bropиs t сh аdеi yеars ago thеrе appеar cus аnсlnlеnsls that pos ( L е a k е ye t a I . 1 9 9 5 , 1 9

Humаn Еuolution that makе thеm lеss attraсtivе as Hominidaе (МсСrossin and Bеnеr anсеstorsеvolvеd wаs influеnсеd rld сlimatеsovеr thе past 7 million hгеnk 1999; Potts 2007; Piсkford s of сold tеmpеraturеsin high latij tropiсs.Thеsе appеаrred at 16_13, nning at 2.5 million yеars ago' thе in highеr еlеvations and latitudеs :quatoriallands, еspесiаlly Afriсa. of thе Аfriсan apеs and humans) rd of hominids in thе Мiddlе and Lndalmostnothing is known of thе rillas. Surprisingly, muсh morе is nсh, thе Нomininaе.

nininaеis guidеd by undегstanding tiсs. Thе moiесular сloсk Ьraсkеts .n 10 and 5 milliоn yеars Ьy most :s,thе еarliеstanсеstor of humans s uniquе to thе linеagе.This is oЬw s o f p r е - H е n n i g i a nс o m p a r a t i v е an еvolutionarystudiеs.lf it looks .Wе l from thе human rеirlm' now r apеlikе-Ьесonrirrg-humanlikе sеhis sеquеnсеlooks vеry apеlikе. By 'uld еxpесt. p i n r h е s u Ь Г a m i | yH o m i n i n a е i s 2002). This prесious fossil skull lntainеd faunа linkеd with dataЬlе 'to 6 million yеars aЕ]o.Its ovеrall еstimatеdbrain size slightly Ьеlow 1). But Ьv rhе Iogiс of сladistiсs, it аt dеfinеour linеagе.Thе most imt h а t o f а p е s а n d 1 r r i m a t е si n g е n lwеr prеmolar. Tlris is a signifiсаnt .tant diffеrеnсе Ьеtwееn apеs and t872) notеd that whеn human anands and сould Ьrаndish wеapons lg on largе сaninеs' Smаll сirninеs l diffiсult to inragirrеothеr rеasons

for sеlесtionthаt favоrs rеduсtion to rеliеvе thе еxpеnsе of growing suсh daggеrs.Anothеr hominin novеlty sееn in S. tсbаdensis is thе forward plaсеmеnt of thе foramеn magnum' In ovеrall morphоlogy (Zollikofеr еt al. 2005), howеvеr, Sаbеlапthroprzs is apеlikе, as Ьrfits a spесiеs сlosе to thе origin of thе human linеagе.Its Ьrain is minusсulе сompаrеd with that of modеrn hц_ mans.It has еnormous brow ridgеs that аrе еvеn largеr than thosе of modеrn apеs or еarliеr mеmЬеrs of thе gеnus Homo whеrе Ьrow ridgеs appеar aftеr havingЬееn lеss dеvеlopеd in еarliеr spесiеsof our linеagе. Thе disсоvеrу of Sаhеlапthropus is duе ttl the pеrsistеnсе,skill, and сlеvеrnеssof Miсhеl Brunеt and his tеam' inсludiпg DjimdoumaЬayе Ahounta' thе Сhadian studеntwho found thе skull. Its loсation 2'500 km wеst of thе Еаst Afriсan Rift, whеrе almost аll thе othеr еaгliеst hominins wеrе found, rеminds us to Ье mindful of thе limitеd ехtеnt of ouг sаmplе. Almost all of thе vеry еarliеst fossil rесord of our еvolutionary history сomеs from thе Afriсan Rift Vallеy. Bесausе of еxtraordinary gеologiсal еvеnts' many latе Mioсеnе to Rесеnt tеrrеstrial fauna arе prеsеrvеd in sеdimеnts layеrеd Ьy volсaniс ashеs that сan Ье datеd by thе radioaсtivе dесay of naturallyoссurring potаssium-40 to argon-4O.Fossils Ьuriеd bеnеath layеrs of ash in Еthiopia, Kеnya, and Tanzаnia pгovidе most of thе еvidеnсе for thе еarly paгt of thе stoгy of human еvolution arrd thе сonteхt in whiсh it oссurrеd. Thе first сhaptеr in this story сoпlеs from fossils Ьеnеath ash layеrs datеd to just lеss than 6 million yеars ago in thе Tugеn Hills of Kеnya (Sеnut еt al. 2001; Piсkford еt al. 2002; Sawada еt al. 2002). Namеd Оrrorin tugепeпsis, this spесiеsсomЬinеd apеlikе tееth and forеlimЬs with humanlikе thighs that appеar to bе adаptеd to Ьipеdality (Piсkford еt al. 2002; Riсhmond and Jungеrs2008). Slightly latеr in timе (5.8_4.4 million yеaгs ago) is thе сollесtion of thе Еthiopianspесinrеnsrеfеrrеdto as Аrdipithеcus (Hal|е.Sеlаssiе2001; WoldеG a Ь r i е lе t a l . 2 0 0 1 ; H a i l е - S е l a s s i е t а l . 2 0 0 4 ; W h i t е e t a l r .| 9 9 4 , t 9 9 5 ) . A s witЬ Оrroriп tt,tgепепsisand as ехpесtеd in аn еarly anсеstor' it is apеlikе in most rеspесts,Ьut it doеs sharе сеrtain kеy traits with latеr hominins. Among thеsеis a сaninе tooth that is lеss projесting and lеss pointеd than that of fossil or modеrn apеs and a сraniаl Ьаsе that is shortеr. Its toеs apparеntly had thеaЬility to hypеrехtеndlikе thosе in Ьipеdal humans (Hailе-Sеlassiе2001). It livеd in a сlosеd woodland еnvironmеnt (WoldеGaЬriеl еt аl' 1994.200t\.

AшstrаIopithecusand othеr Hominins 4.2_2.5Мillion Yеars Ago Thе fossil еvidеnсе for hominin Ьipеdality is hintеd in intеrprеtations of Sаhеlапthropustchаdeпsis, orrorin, and Аrсlipithесus' ЬutЬу 4.2_З.9 million yеarsago thеrе appеar in thе fossil rесord fossils attriЬutеd to Austrаlopitheсusапаmensisthаt PoSsеSsa shinЬonе with nut-tlеrousЬipеdal spесializations ( L е a k е yе t a | . | 9 9 5 , 1 9 9 8 ; ! 7 a r d е t a l . 2 0 0 1 ; W h i t е е t a L . 2 0 0 6 ) .T h i s s p е с i е s

26З

264

Humап Еuolutioп rеtains numеrous apеlikе сharaсtеristiсs,likе its prеdесеssor'Ьut shаrеsсеrtаin еvolutionary novеltiеswith all latеr hоminins that aге not pгеsеntin thе more primitive Ardipithеcus' Мost сonspiсuous is thе thiсkеning of еnamеl that Ьесomеs сharaсtеristiсof all lаtеr hominins. Its uppеr сanine has thiсkеnеd enamеl on thе сhееk sidе of its apех. Thе molars аrе ехpalrdеdfrom sidе to sidе, and thе first and sесond molars arе not markеdly diffеrеntin sizе. Thе еаr tuЬе is morе humanlikе. Its dесiduous lowеr first molar is rе. poгtеd to Ье intеrmеdiatе Ьеtwееn thosе of Аrdipitheсus and A. аfвrensisin sizе and shapе. In thе rеst of thе skеlеton it is vеry muсh likе latеr hominins (fеw dеtails of Аrdipithесus ate puЬlishеd), еspесially its еlbow, knее, and anklе. Thе samplе of А. аfаreпsis (3,6_2.9 million yеars ago) is Ьеst known from Laеtoli (Tanzaniа) and Hаdar (Еthiopia), is latеr in timе than А. апаmeпsiц and sharеs dеrivеd сharaсtеristiсs with latеr hominins suсh as an еar tubе that is more roundеd in outlinе, а сaninе with a shortеr сrown аnd highеr shouldеrs, a morе humanlikе lowеr first dесiduous molar and pеrmanеnt prеmolar' and a lеss sloping сhin. Also, onе of thе wrist Ьonеs (thе сapitatе) is lеssprim. itivе (although not fully modеrn) (Johаnsonеt al. 1982; Lеakеy eta|'\995, 1998; Whitе et a|. 2006; Alеmsеgеdеt al. 2006; KimЬеl et aL.2006)' Kепуапthropus plъtуops (3.5-3.3 million yеars ago) ovеrlaps in timе with A. аfаrепsis Ьut appеars to Ье quitе distinсtivе irr its moгphologv (Lеakеy еt al.2001). In somе rеspесtsit is moге primitivе than its сontеmporary.tоr еxamplе, it laсks a pеtrous сrеst on thе tympaniс Ьonе and has a narrow eхtеrnal еar ttrЬе with a small apеrtuге morе likе that in еarliеr homininsand not likе that in А, аfаrеnsis. In othеr respесts it rеsеmЬlеs muсh lаtеr hominins' partiсularly H. rudolfепsis,in having a rеlагivеlyflat faсе,tall сhееks, smаll molars, and forward faсing сhееkЬonеs. Thеsе lattеr traits arе rеlаtеd ..suggеsts a diеtto mastiсation that' aссording to Lеakеy еt аl. (2001,437), drivеn adaptivе radiation among horninins in this timе intегval.''It is possiЬlе that thе rеsеmЬlanсеs Ьеtwееn H. rudolfeпsls and K. plаtуrlps arе duе to phylogеnеtiсаlly indеpеndеnt еvеnts drivеn Ьy adaptations to similar situations and arе, thеrеЬy,onе morе ехamplе of thе pеrvasivеnеssof homoplasy' It is еqually possiЬlе that thе rеsеmblanсеsrеprеsеnttruе homology and imply a сladе that links К. plаtуops with H. rudolfепsis' Lеakеy еt al. (2001)fa. vor thе lattеr viеw, whiсh suggеsts transfеrring H. rudolfeпsls to thе gеnus Keпуаnthro1lus (i.e., K. rudolfепsls). Although thе fасе of Kепуапthropus appеars similar to that of H. rиdolferz'sls,somе or all of this rеsеmЬlanсеmayЬе duе to ехpаnsion сraсks that havе distortеd Kenуапthropиs сonsidеraЬly (Whitе200з). Thе nехt-oldеsthominin spесiеsis А. gаrbi (2.5 nrillion yеars ago).It has somе sharеd dеrivеd traits with latеr and сontеmporary hominin spесiеsrеlativе to А. аfаrепsis (Asfаw et a|' 1999\. Rеlativе to А. аfаrепsls, ir sharеs ..roЬust'' australopithесinеs aЬsolutеly and rеlаwith А. аfriсапus and thе tivеly largеr сhееk tееth. Its uppеr third prеmolaг is rеportеd to havе a morе oval outlinе аnd nо mеsioЬuссal linе eхtеnsion. Its prеmolars arе Ьеginning to show somе еХpansion (molarization), and its еnamеl is thiсkеr. Its uppеr

inсisor roots arе no l A. аfаrепsis. Thе rеIаtir angle arе Ьеginning to l hominin еxсеpt P. аеtbt Тhе South Afriсan sр сontеmpoгary with А. . somе traits that appеar spесiеs (Asfaw еt al. 19 mеdial to thе nasal apе, nathism, rеduсеd inсiso faсial сontour.

Thе ..Robust,,Aus

In 1938 RoЬеrt Broom еvolution Ьy his dеsсri; Its teеth, jаws, and faсе Broom and suЬsеquеnt tion (RoЬinson 1972). shаrеs many dеrivеd fеа mаy Ье сlosеly rеlatеd l minins togethеr as ..roЬ аppropriatе. Thе еarliеs (2.7_2.З million yеars a[ Ьusts'' ot Нomo that arс massivе сhееk tееth anс сharaсtеristiсs of A. аfаr' P. robustus (2-1 million do sharе apparеnt еvolu tralopithесinеs, suсh as i of thе palatе, rarе or aЬs a v а r i а Ь I еt t l w е a k с a n i and еnlargеd Ьrain (Skеl Grinе 2004).

Origin of Homo

onе might dеspaiг at thс genus Homo, Ьut from t traits' thе fossil rесord is duсе. In onе spесiеs, FI. l to rеmain likе that of А and powеrfully built sho thе assoсiation of the hir

Humап Еt,olution ikе its prеdесеssor,Ьut sharеs сеr. эminins that arе not prеsеnt in thе сuous is thе гhiсkеning of еnamеl ninins. Its uppеr сaninе has thiсkк. Thе moiаrs arе ехpandеd from lars arе not nrarkеdly diffеrеnt in dесiduouslowеr fiгst molar is rеff Аrdipithеcus and A. аfаrеnsis in it is vеry muсh likе latеr hominins J), еspесiallyits еlbow' knее, and lion yеаrs ago) is Ьеst known from is latеr in timе than А. апаmeпsis' r homininssuсh as at] еar tuЬе that a shortеr сrown and highеr shoulus moiar аnd pеrmаnеntprеmolar, 'istbonеs(thесapitatе)is lеss prim_ r n е t a l . 1 9 8 2 ;L е a k е у e t a | . 1 ' 9 9 5 , 1 0 0 6 ;K i m Ь е l е t а l . 2 0 0 6 ) ' )n yеars ago) ovеrlаps in timе with inсtivе in its rnorphology (Lеakеy 'imitivе than its сontеmporary. For mpаniс Ьonе and has a narrow еx_ .е likе that in еarliеr hominins and ;pесts it геsеmblеs muсh latеr lroing a rеlativеlyflat faсе, tall сhееks, эnеs.Thеsе lattеr trаits аrе rеlatеd эt al. (2001, 437)' ..suggеstsa diеt; in this timе intеrvаl.''It is possiЬlе fensis aпd K. plаtуops arе duе to :n Ьy adaptationsto similar situaof thе pеrvasivеnеssof homoplasy. s геpresеnttruе hornology and im"udolfensis.Lеakеy еt al. (2001) fаЪrring H. rudolfeпsis to thе gеnus lugh thе faсе of Кenуаnthro1lus aplе or all of this rеsеmЬlanсеmay Ье ttеd Кeпуаntbroptts сonsidеraЬly ,аrhi (2.5 million years ago). It has сontеmPoraryhоminin spесiеs rеlRеlativе to А. аfаrеnsls, it sharеs rаlopithесinеsabsolutеly and rеlarеmolaris rеportеd to hаvе a morе lnsion'Its prеmolаrs arе Ьеginning rnd its еnamеl is thiсkеr. Its uppеr

inсisor roots arе no longеr latеral to thе nasal apеrturе' as thеy arе in А. аfаreпsis.Тhе rеlativеsizеsof thе postеrior tеmporalis аnd pariеtomastoid anglеarе Ьеginningto rеduсе, as thеy do in all othеr spесiesof post-аfаrепsis hominin ехсеpt P' аеthiopiсus. Thе South Afriсan spесiеs'A. аfricапus (3_2 million yеars ago), is roughly сonteпporary with А. gаrhi and latеr in timе than А. аfаrensis. It possеssеs somе traits that appеar to Ье dеrived and sharеd witЬ Homсl rеlativе to thеsе spесiеs(Asfaw et aI. 1999)' Thеsе inсludе uppеr latеral inсisor roots that arе mеdialto thе nasal apеrturеJа flаttег сlivus сontour, rеduсеd suЬnаsal prognathism'rеduсеd inсisor proсumЬеnсy' and rеduсеd Ьipartitе latеral anteгior faсiai сontour.

Thе ..RoЬust''Australopithесinеs In 1938 RoЬеrt Broom гесognizеda mostly unantiсipatеdсhaptеr in human еvolutionЬy his dеsсription of whаt hе сa||еdPаrапthropиs (Bгoorn 193s). Itstееth,jaws, and faсе wеrе massivеly Ьuilt (hеnсеthе namе robustus\, and Broom and suЬsеquеntauthors rеgardеd it аs a sidе Ьranсh of human еvolution (Robinson 1972). Howеvеr, in many important rеspесts Pаrаnthropиs sharеsmany dеrivеd fеаturеs witЬ Homo (Skеlton and МсHеnrу 1992) and may Ье сlosеly rеlatеd to ouг gеntls. It is сomnron to lump lагgе_tooth homininstogеthеras ..roЬust'' australopithесinеs,Ьut this grouping may Ье inappropгiatе.Тhе еarliеst of thе ..roЬust'' austгаlopithесinеs,P. аethiopiсus (2.7-2.Зmillion yеars ago), sharеsr.еryfеw dеrivеd сharaсtеrswith latеr ..roЬusts''or Homсэ tlrat arе not rеiаtеd to hypеrmastiсаtion(Grinе 1988). It has massivе сhееk tееth and сhеwing appаratlrs Ьut rеtains thе primitivе skull сharaсtеristiсsof А. аiаrепsis (!Иalkеr et aI. 1986), Thе latеr ..roЬust'' spесiеs, P. robustus(2_1 million yеars ago) arrdP' boisei (2'З-I.4 million yеars ago), do sharе apparеnt еvolutionaгy novеlties with Нoпo rеlativе to othеr australopithесinеs, suсh as a paraЬoliс dеntal arсadе shapе, dееp antеrioг depth of thе palatе' rarе or absеnt diаstеma betwееn thе uppеr inсisors and сaninе, a variаЬlеto wеak саninе jugum and fossa, rеduсеd sr-rЬnasal pгognаthism' and еnlaгgеdЬrain (Skеlton and N{сHеnrу 199\ Strait еt a|.7997i Strait and Grinе 2004).

Origin of Homo onе might dеspair at thе apparеntly сonfliсting еvidеnсеfor thе origin of thе geпls Homo, Ьut from thе pеrspесtivе of the ассumulation of sharеd dеrivеd traits'thе fossil rесord is lеss pеrplехing. Brains ехpand, and сЬееk tееth rеduсе'In onе spесiеs,H, hаbilis (2.з_1.6 million yеars ago), thе Ьody appеars to rеmain likе that of АltstrаIopithecиs,small with rеlаtivеly long forеarms andpowеrfully Ьuilt shouldеrs (Haеuslеr and МсHеnrу 2007).If onе aссеprs thеassoсiаtionof thе hindlimb fossils found at thе samе sitе and timе as thе

26''

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Humаn Еuolutioп сrаniodеntal rеmains of H. rиdolfeпsis (-1.9 million yеars ago) as Ьеlongiпg to that spесiеs' thеn the morе humanlikе Ьody proportions and hip arсhitесturе first appеar in this spесiеs just aftеr 2 million yеars ago (MсHеnry and Сoffing 2000). Both of thеsеspесiеsarе transitional,with somе primitivе and somе dеrivеd сharaсtеristiсs of latеr Homo. Postсranial assoсiations arе сritiсal hеrе Ьесausе Ьody sizе appеars to Ье vеry diffеrеnt. Homo hаbilis was vеry small Ьodiеd (35 kg), and H. rudolfensis was lаrgе (55 kg) (МсHеnry 1'994ь|.Sсaling сhееk-toothsizе to Ьody wеight shows that thеy Ьoth had rеvеrsеd thе trеnd of еvеr-inсrеasingсhееk-tooth sizе. Rеlativе Ьrain sizе еxpandеd, еspесially in H. bаbilis' AЬsolutе Ьrairr sizе ехpands furthеr with thе appеaranсе ol 17.ergаsterlеrесtus Ьу at lеast 1.8 million yеars аgo, Ьut Ьody sizе also inсrеasеs,so rеlаtivе brain sizе apparеntly Was not dramatiсally ехpandеd (lХ/аlkеr and Lеakеy 1'99З).Thе еarly Afriсan form of this spесiеsis oftеn rеfеrrеdto as thе spесiеs H. еrgаster to сontrast it with thе wеll-known Asian samplе of H. ereсtus (.!Иood1991; Spoor et a|. 2ОО7|. Body size and еspесially hindlimЬ lеngth .Walkеr rеaсh modеrn proportions in this spесiеs (Ruff and 199З). othег synapomorphiеs with |ater Homo inсludе a furthеr rеduсtion in prognathism, a rеduсtion in thе postglеnoid proсеss that is fusеd with thе tympaniс platе, and rеduсtion in thе aЬsolutе and rеlativе sizе of thе сhееk tееth. Brains сontinuе to еxpand, and сhееk tееth get progrеssivеlysmallег during thе еvolution оf thе gеnus Homo.

First Dispеrsal out of Afriсa Thе first appеaranсе of human populations outsidе Afriсa appеars to havе oссurrеd soon аftеr thе appеaranсе of еarly Homo in Afriсa. Fossil Hoиo rеmains from thе Dmanisi sitе in thе RеpuЬliс of Gеorgia arе most likеly oldег than 1'.7 million yеars and arе vеry muсh likе thosе found in Afriсa attrib. utеd to H' erесtцs/bаbilis (GaЬunia and Vеkua 1995; GaЬunia еt al. 2000; Vеkua et al. 2002; Lordkipanidze еt a|. 200 5, 2007 ). Нomo еrесtus oссupied parts of tropiсal Asia pеrhaps аs еarly as 1.8 million yеаrs ago (Swishеrеt al' |994). Thе ехaсt сhronology is still unсеrtain, Ьut somеtimе aftеr this and bеforе 0.5 million yеars ago some populations hаd adaptеd to lifе in thе tеmpегatе сlimatiс zonе of northеrn Asia (Ant6n and Swishеr 2001). An arсhaiс spесiеsof Homo lеft tools on thе island of Florеs, Indonеsia,as еarly as 800,000_700,000 yеars ago (Brumm еt al. 2006; Morwood еt аl. 1998)' and in surprisinglyyoung sеdimеnts(95,000-12,000 yеars ago) a nеw spесiеs, H. floresiепsls, has Ьееn rесovеrеd (Brown et a|. 2004; Mоrwood et a|. 2О04,2005; Мorwood and vаn Oostеrzee 2007).It has a small Ьody (29 kg)' minutе еndoсranial volumе (380 сс), and arсhaiс Ьody (Larson еt al. 2007; Toсhеri еt al. 2'007).It is most likеly a dеsсеndantof an еarly dispеrsal of arсhaiс Homсl that undеrwеnt insular dwarfism (Brown еt al. 2004), although sоmе сhallеngе this intеrprеtation (Arguе et a|. 2О06; JaсoЬ еt al. 2 0 0 6 ; H е r s h k o v i t ze t a | . 2 О 0 7 ) '

Thе gеologiсаlly lаtе < dеmonstratеs thе fallaсy progrеssive stagеs. Populi othеr populations unlеssс

Arсhaiс Homo to Hс

Largег-Ьгаinеd spесiеstl 600,000 yеars ago and in Nеandеrtals dominatе E 3 0 0 ' 0 0 0 t o 4 0 , 0 0 0 y е a r si H' sаpiепs appеars 6rst in 1999, 2000). Thе еarliеs latеr Ьесamе thе hallmark suЬ-Saharan Afriсa Ьеfor .}иIсBrеartyand Brooks 20( spесiеs sprеad out of Afriс gеnеtiсally swamping loс GoеЬеl 2007). Thе sprеa еаrly (50,000-46,000 yеar aЬly Ьеlongеd to modеrn l old as 40'000 yеars (Bowlt from Asia who migratеd Alaska pеrhaps 20,000 to of most of thе Amеriсaь GoеЬеl еt al. 2008). Pеop thousand yеars ago from tl д.п. 300 and Nеw Zea|and 2007; Hunt and Lipo 2006 Tесhnologiсal dеvеlopm paсе, Ьut it сеrtainly shows сrudе stonе tools pеrsist fol аrе muсh morе rесent. Hu] l е s st h а n 0 . 2 5 " Ь o f t h е i r е v linеаge. Thе historiсal distrtЬutiо vеiopеd only in thе past 40, ezs еquippеd with Uppеr Afriсan homеland, first to , Еuropе (Klеin 1999). This genеtiс homogеnеity found with that of our own сlosе dеgrее of gеnеtiс hеtеrogеn that in Homo sаpieпs (Ga1 tions to loсal сonditions ar

Humаn Еuolution l million yеars ago) as Ьеlonging dy proportions and hip arсhitесnillion yеaгs ago (MсHеnry and sitional,with somе primitivе and P o s t с r а n i aаl s s o с i a t i o n sа r е с r i t еry diffеrеnt. Homo hаbilis was sls was largе (55 kg) (МсHеnry ight shows that thеy Ьoth had rе) O t hs i Z е .R е l а t i v е Ь r a i n s i z е е x lе appеaranсе of H. еrgаster/erесdy sizе alsо inсrеasеs,so rеlativе . ехpandеd (Walkеr and Lеakеy i is oftеn rеfеrrеd to as thе spесiеs own Asian samplе of H. ereсtиs э and еspесially hindlimЬ lеngth (Ruff and !Иalkеr 1,99З). othеr е a furthеr rеduсгion in progЭсеssthat is fusеd with thе tymrd rеlativеsizе of thе сhееk tееth. l get progrеssivеlysmallеr during

s outsidе Afriсa appеars to havе Homo in Afriсa. Fossil Hozao reс of Gеorgia arе most likеly oldеr likе thosе fоund in Afriсa attribеkua 1995; GaЬunia еt al. 2000; l5,2ОО7\.Homo ereсtusoссupiеd 8 million yеars ago (Swishеr еt al. tain' Ьut somеtimе aftеr this and lns hаd adaptеdto lifе in thе tеmi n a n d S w i s h е r2 0 0 1 ) . thе island of Florеs, Indonеsia, as mm еt a|. 2006; Morwood еt al. (95,000_12,000yеars ago) a nеw d (Brown et al. 2004; Morwood ;terzee2О07).It has a small Ьоdy с), and arсhaiс Ьodу (Larson еt al. a dеsсеndantof an еarly dispеrsal jwarfism (Brown еt al. 2004), alL (Arguе еt a|, 20ОQ JaсoЬ еt al.

Thе gеоlogiсally latе oссurrеnсе of suсh a primitivе spесiеs of Homo dеmonstratеsthe fallaсy of rеgarding human еvolution as passing through pтogrеssivеstagеs.Populations adapt to loсal сonditions and divеrgе from othеrpopulations unlеss сhесkеd Ьy gеnе flow.

Arсhaiс Horпo to Horno sаpieпs Largеr-Ьrainеd spесiеs of arсhaiс Нomo Ьеgin to appеar in Afriсa Ьy 600,000 yеаrs ago and in Еurasia somеwhat latеr (Сlark et a|. 1'994).The Nеandеrtаls dominatе Еuropе and wеstеrn Asia from approхimatеly 3 0 0 , 0 0 0t o 4 0 , 0 0 0 y е a r s a g o ( K l е i n 2 0 0 3 ; K u h n 2 0 0 7 ; K r a u s е е t a | . 2 0 0 7 ) . Н. sаpieпsappеars first in Afriсa somеtimе Ьеforе 100,000 yеars ago (Klеin 1999, 2000). Thе еarliеst traсеs of Uppеr Palеolithiс tool tесhnology that latеr Ьесamе thе hallmark of еarliеst mеmЬеrs of H, sаpieпs first аppеаr in suЬ-SaharanAfriсa Ьеforе aЬout 90,000 yеаrs ago (Brooks et a|. 19951 МсBrеarty and Brooks 2000). By aЬout 50,000 yеаrs ago populations of our spесiеssprеad out of Afriсa to Asia and thеn Еuropе, apparеntly rеplaсing or gеnеtiсallyswamping loсal arсhaic Homo populations (Anikoviсh 2007; GoеЬеl 2007). Thе sprеаd Was apparеntly rapid in Asia, as еvidеnсеd Ьy early (50,00046,000 yеars old) arсhaеologiсaltraсеs in Australia that proЬaЬly bеlongеdto modеrn H. sаpiепs populations found thеrе in sеdimеntsas old as 40,000 yеars (Bowlеr еt al. 2003). Amеriсa Was sеttlеd Ьy immigrants from Asia who migratеd aсross a land Ьridgе that сonnесtеd SiЬеria and Alaska pеrhaps 20,000 to 15'000 yеars ago' Ьut thе suссеssfulсolonization of most of thе Amеriсas bеgan aЬout 12,000 yеars ago (Dillеhay 2003; GoеЬеl еt al. 2008). Pеoplе first rеaсhеd somе of thе Paсifiс islands sеvеral thousandyеars ago from thе еast, arriving at thе Мarquеsas Islands Ьy aЬout д.o. 300 and Nеw Zea|and Ьy aЬout д.о. 1200 (Lum and Сann 1998; Finnеy 2007; Hunt and Lipo 2006). Tесhnologiсаl dеvеlopmеnt in human еvolution appеars to Ье еrrariс in paсе'Ьut it сеrtаinly shows a pattеrn of aссеlеration(Klеin \999). Relativе|y сrudеstоnеtools pеrsist for ovеr 1.5 million yеars. Finеly workеd Ьladе tools arе muсh morе rесеnt. Нumans havе had agriсulturе' сitiеs, and writing for lessthan 0.25% of thеir еvolutionary dеvеlopmеntas a sеparatеmammalian linеagе. Thе historiсal distriЬution of human gеnеtiс variаtion аppеаrs to havе dеvеlopеdonly in thе past 40'000 to 50,000 yеars whеn populations of H. sаpiсиs еquippеd with Uppеr Рalесllithiс tool tесhnology sprеad out of thеir Afriсan homеland' first to Asia and Ьy at lеast 30,000 yеars ago throughout Еuropе (Klеin 1999). This reсеnt сolonization ассounts fоr thе rеmarkaЬlе gеnеtiсhomogеnеity found among living mеmЬеrs of our spесiеs сomparеd with that of our own сlosеst Ьiоlogiсal rеlativеs, Pап and Gorillа' whеrе thе dеgrееof gеnеtiсhеtеrogеnеitywithin еaсh spесiеsis manу timеs grеatегthan that in Homo sаpiеl1s(Gagnеuх et a|. 1999; Ruvolo 1997). Rapid adaptationsto loсal сonditions and thе random sеnеtiс сhaneеs that саn oссur in

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Humап Еuolutioп small isolatеd populations havе lеd to sеvеral сonspiсuous phеnotypiс сhangеs, suсh as skin сolor, hair form and сolor, and Ьody proportions' Ьut thеsе diffеrеnсеs appеar to Ье rеlatively rесеnt altеrations. Thе gеographiс distriЬution of skin сolor is сlosely сorrеlatеd with thе intеnsity of solar radiation suсh that tropiсal pеoplе in Afriсa, Asia, and thе Amеriсas havе grеat dеnsity of mеlanin pigmеnts in thе skin for protесtion аgainst tissuе and mеtaЬoliс damagе. Highеr-latitudе pеoplе arе dеpigmеntеdmost likеly Ьесausе ultraviolеt radiation from thе sun сatalyzеs thе synthеsis of vitamin D in thе skin and Ьесausе of othеr faсtors (JaЬlonski and Сhaplin 2000). Dеpigmеntation of thе skin in high-latitudеpеoplеs appеars to Ье truе of Nеandеrtals (Сulotta 20О71 Lalueza-Foх et a\. 2007). Body proportion variеs gеographiсally aссording to tеmpеrаturе' so that pеoplе in hot сlimatеs havе longеr limЬs and lеss gloЬular trunks to allow grеatеr hеat dissipation through thе skin (Ruff 1994). Ехсеptions to this pattеrn сan oftеn Ье ехplainеd Ьy thе prеsеnсе of сultural аdaptations that allow prеfеrеntial survivаl and rеproduсtivе suссеss indеpеndеnt of gеnеtiс аdaptations. Thе first H, sаpiепs in Еuropе, foг еxamplе, had Ьody Ьuilds сharaсtеristiс of tropiсal pеoplе (thеy сamе from Afriсa), Ьut thеy had tесhnologiеs far supеrior to thosе of thе loсal Nеandеrtаls. Tесhnologiсal innovation is oftеn thе rеason for population еxpansion and plays a pгofound rolе in dеtеrmining why сеrtain physiсal variеtiеs of H' sаpiens oссupy gеographiс rеgions and displaсе еarliеr indigеnous pеoplе (Diamond 1997).

Еvolution of thе Human Brain Thе aссumulation of еvolutionary novеltiеs through timе rеvеals thе сontinuity of human еvolution. Thе dеmonstration of this сontinuity is a triumph of еvolutionary Ьiology. It furthеr сonfirms Darwin,s viеw of dеsсеnt with modifiсation. Thе ехpansion of thе Ьrain in thе hominin linеagе is onе of thе most dramatiс dеmonstrations of this. Absolutе and rеlativе Ьrain-sizе еxpansion follows timе rеmarkaЬly wеll, as shown in ТaЬlе 1. Thе еarliеst speсiеs for whiсh Ьrain sizе is known, А. аfаreпsis' has an avеragе еndoсrаnial volumе of 4З8 сс (Ьasedon 4 spесimеns),сomparеd with modеrn сhimps at 400 сс' gorillas at 500 сс' and H' sаpiепs at 1,350 сс. Thе еndoсranial volumе for А. gаrhi \1 spесimеn) is rеportеd to Ье 450 сс, for А. аfricапus (7 spесimеns)' 4 5 2 с с , f o r P . b o i s е i ( 1 s p е с i m е n,)5 2 1 c c , f o r P ' r o b u s t и s( 1 s p е с i m е n ) 5' 3 0 сс, for H. hаbilis (6 spесimеns), 6|2 сc, for H. rudolfепsis (1 spесimеn), 752 сс' and for Н. ergаster (З spесimеns), 871 сс. Howеvеr' at lеast onе spесiеsof Homo (H. |loresiепslsl managеd to survivе on a rеmotе island until 18'000 yеars ago with аn еndoсranial volumе of only 380 сс (Brown et a|.2О04). Brains eхpand during thе Plеistoсеnеfrom 914 сс Ьеtwееn 1.8 and 1.2 million yеars ago to 1,090 сс Ьеtwееn550,000 and 400,000 yеars ago' 1,186 cс bеtwееn 300,000 and 200,000 yеars ago' and aЬovе 1,300 сс aftеr 150,000 yеars ago (Ruff еt aL. 1998). Rеlativе to еstimatеd Ьody wеight, thе fossil spесiеsgo from slightly aЬovе thе sizе sееn in modеrn apеs to 5.4 timеs thе

mammalian avеragе (thе t i o n s k е p t u p w i г h Ь г а i nt sis (Brown et a\. 2ОО4), еndowеd with modеrn Ьr s u Ь j е с гo f Ь r а i n r е o r g e n aЬly profound сhangеs t othеr uniquеly human fa< tiс сhangе that еnaЬlеd Ё haviors Ьеginning aЬоut ]

Еvolution of Humar

Bipеdalism is thе first mz first hominins wеrе mos Ьodiеs without thе spесi mark of our linеagе (Tho possiЬly Еuropеan radiat win's woгds, ..to livе som ..a сhangе in its mannеr t ditions of its native сoun thе human сladе proЬaЬ еvolutionary novеltiеs. l that pгoduсеd thе Ьipеd dеfinе thе human gradе transformations of thе tr fossil rесord. It may Ье t ratеs so that thе lеngth of of thе halluх. Тhе еxtin pithесus appеars to havе l big toе (Kohlеr and Мо rаmidus will hеlp сlarify < Ьipеdаlity in our linеagе. Еarly еvolutionists, rr Нaесkеl (1868), prеdiсt Ьrain. How' why, and i uniquе рosturе is a favor 2004). It is possiЬlе tha Ьipеdality, givеn thе faсt t wiгh foгеlimЬ suspеnsio Ьipеdal, this Ьody plan сa quadrupedal mammals а (Rodman and МсHеnry l Thеrе has Ьееn a pесul primitivе traits rеtainеdin Onе polе еmphasizеsthе 1

Humап ЕL'olutioп 269 sеvеral сonspiсuous phеnotypiс сolor, and body propoгtions, but есеnt altеrations. Thе gеographiс еd with thе intеnsity of solaг гadi\sia, and thе Aпrеriсas havе grеat for protесtion аgаirrst tissuе and , arе dеpigmеntеdmost likеly Ьe,talyzеsthе synthеsis of vitamin D laЬlonski and Chaplin 2000). Dееoplеsappеarsto Ье truе of NеanI. 2007). Body proportion variеs ;o that pеoplе in hot сlimatеs havе o аllow grеatеr hеat dissipation j to this pattеrn сan oftеn Ье еxations that allow prеfеrеntial surrt of gеnеtiс adaptations. Thе first dy Ьuilds сharaсtеristiсof tropiсal ' had tесhnologiеsfaг supеrior to iсal innovation is oftеn thе rеason .oundro1еin dеtеrminingwhy сеrly gеographiсrеgions and displaсе

ls through timе rеvеals thе сontinun of this сontinuity is a triumph of )агwinЪviеw of dеsсеntwith mod_ : hominin linеagеis onе of thе most з a n d r е l а t i v еЬ r а i n . s i z ее x p a n s i o n in TaЬlе 1. Thе еarliеst spесiеs for las an avеragееndoсranial volumе геdwith mоdеrn сhimps at 400 сс' l сс. Thе еndoсranialvolumе for А. сс, for А, аfriсаnиs (7 spесimеns), , for P, robustus (1 spесimеn)' 530 х H' rudolfепsis\I spесimеn), 752 сс. Howеvеr, at lеast onе spесiеs of vе on a rеmotе islаnd until 18,000 only 380 сс (Brown еt al. 2004). > m 9 t 4 с с Ь е t w е е n1 . 8 a n d 1 . 2 m i l ) 0 a n d 4 0 0 , 0 0 0 y е a г sa g o ' 1 , 1 8 6 с с , and abovе 1,300 сс aftеr 150,000 ' еstimatеdЬody wеight, thе fossil еn in modеrn аpеs to 5.4 timеs thе

mammalianavеragе (thе сolumn laЬеlеd ЕСV in TaЬlе 1). Not all pсlpulatiоnskеpt up with Ьrаin ехpansion, аs is dramirtiсallyshown Ьу H. flrlrеsiensls (Brown еt al. 2004), Ьut all ехtant populations of H. sаpieпs arе fully еndowеdwith modеrn Ьгairrs.Unfortunatеly thе fossil rесord is mutе ()n thе suЬjесtof Ьrain rеorganizаtion,whiсlr is а pity Ьесаusеthеrе wеrе prеsumaЬly profound сhаrrgеsthat aссompаniеd thе dеvеlopmеnt оf spеесh and othеruniquеly hurrranfaсultiеs.A strong сi1sесan Ье madе for a major gеnеtiс сhangеthat еnaЬlеd H. sаpiепs to spеak аnd pеrform modеrn human ЬеhaviorsЬеginningaЬout 50,000 yеаrs ago (Klеin and Еdgar 2002).

Еvolution of Human Walking Bipеdalismis tlrе first major gradе shift in hominin еvolution, Ьr.rtthе vеry first hominins wеrе most likеly gеnеralizеd hominoids with rathеr аpеlikе Ьodiеswithout thе spесializationsfoг Ьipеdаlism that latеr Ьесamе thе hallmark of our linеagе (Thorpе et a|. 2007). Thеy wеrе part of thе Afriсirn and possiblyЕuropеan radiation of latе Мioсеnе hominoids that сamе, in Dar..to livе win'swords, somеwhat lеss on trееs and morе on thе ground'' duе to ..a сhangеin its mаlrnег of proсuring suЬsistеtlсе'or to a сhangе in thе сonditionsof its nativе сountry'' (Darwin 7872, p. l.]5)' Тhе fiгst memЬеrs of thе human сlirdе proЬaЬly will Ье rесognizеd in thе fossil rесord Ьy suЬtlе еvolutionary novеltiеs. Thе major gеnеtiс/dеvеlсlpmеntaltransformаtions that produсеd thе Ьipеdally adaptеd trunk аnd hindlinrЬ morphology that dеfinеthе human gradе proЬаЬly appеarеd latеr. Thе pгесisе sеquеnсе of transformations of thе trunk and hindlimЬ may nеvеr Ье known from thе fossilrесord. It may Ье that parts of thе Ьipеdal Ьody сhangеd at diffеrеnt ratеsso that thе lеngth of thе pеlviс Ьladеs rеdr'rсеdеarliеr than thе adduсtion of thе hallux. Thе ехtil-lсtand distinсtlу nonhonrinin Мioсеne ape oreopithесusappеars to hаvе had a rеduсеd pеlviс lеngth but rеtаirrеda divеrgеnt Ьig toе (Kohlеr and Moyi-So|Ь' 1997). Тlrе full analysis oi Аrdipithесus rаmiduswill hеlp сlаrify our undеrstandingof thе naturе of thе traI-rsition to bipеdalityin our linеagе. Еarly еvolutionists, inсludirrg Lаmarсk (1809)' Darwin (7872\, and Нaесkеl (1868)' prеdiсtеd that Ьipеdality prесеdеd the ехpansion of thе brain. How, why, arrd in what haЬitat an apеlikе anсеstor adoptеd this uniquеposturе is a favoritе topiс of spесulation (Kingdon 2003; MсНеnrу 2004)' It is possiЬlе that many apеlikе spесiеs in thе Мioсеnе zrdoptеd bipеdality'givеn thе fасt that thе apе bodv plаn is аdaptеd to nroving in trееs with forеlimЬ sr-tspеnsion and not to еf6сiеnt quadrupеdal walkirrg. onсе Ьipеdal,this body plan сan movе with an еnегgеtiс еffiсiеnсy еqual to that of quadrupеdalmammals and muсh grеatеr than thаt of quadrupеdal apes ( R o d m a na n d М с Н е n r y 1 9 8 0 ; S o с k o l e t a L .2 О О 7 | . Thеrе has bееn .r pесuliar polarization of viеws aЬout thе mеaning of thе primitivеtrаirs rеtainеdin thе postсrаniа of еаrly spесiеsof Аustrаlrlpithесus. onе polе еmplrasizеsthе bipеdal spесiаlizations(Lovеjoy 200.5а,2005Ь), and

270

Нumап Еuolиtioп thе othеr polе саlls attеntion t() tl.lе many primitivе сharaсtеristiсs (Stеrn сan Ье sееn 2000). Viеwеd in gгand pеrspесtivе,thе divеrgеntintегprеtatiоl1s as diffеrеnсеs irr еmphasis. Both сamps agrее that all spесiеs of AustrаIopitheсus wеrе Ьipеdal. Тhat impliеs thаt thеsеspесiеsdid not сlimЬ likе apеs. Thеy did, howеvеr, rеtain morphologiсa1 fеaturеsаssoсiatеdwith arborеal. ism for at lеаst :r пrillion yеars аnd a hip arсhitесtuгеdiffеrеnt froпl that of latеr spесiеsof Homсl. That impliеs soше diffеrеnсеfroп-tmсldеrn humans in gait and сlinrЬing аЬility, Ьur thеy did not walk :lnd сlimЬ likе аpеs. Thе publishеd hominin fossil rесord doеs not yеt havе a truе intеrmеdiatе stagе Ьеtwееn an apеlikе and a humanlikе Ьody (МсHеnry and Jones 2006I. Thе postсrаniur-lrof Аustrаlсl1litheсиsrеtаins mally primitivе apеlikе traits Ьut is fundamеntally rеorganizеdand highly spесializеdfor Ьipеdality,unlikе that of any apе (МсHеnry 1986). Тhеrе is a profound altеratiorriIl thе gеnеtiс tеmplatе that produсеd thе short pеlviс Ьladе, adduсtеd halluх, and othеr Ьipеdal traits of this hominin. Thе diffеrеnсе Ьеtwееn Aиstrаlopitheсиs'spositional and loсomоtoг Ьеhavior аnd that sееn in latеr spесiеsof Homo Ьес;rmесlеarеrwith thе disсov. егiеs of postсraniаl fossils assoсiatеd witЬ Н. еrgсtstеr/ereсtиs(]il/illrkеrand ..StrаppingYoшth'' (KNM WT 15000). Thеrе Lеakеy 199З|, partiсularly thе arе striking diffеrеnсеsЬеtwееn thе pеlvis and fеmur of all spесiеs of АustrаIopithесus and those of H. ergаster/еreсtиs,with thе laftеr appеaring muсh morе humrrnlikе (MсНеnrv and Сoffing 2000). This proЬaЬl,vrеgistеrs a nrajor shift in adaptation Ьеtwееl-lАиstrаlopitbесttsand Homo. From this pеrspесtivе'Аustrаlopitheс,/sappеаrs tо Ье :l Ьipеd with frее hirnds ftlr сarrying Ьut Ьеst аdaptеd to short distanсеs and rvith a hеalthy аpprесiation of trееs for safеty, fееding, and slееping. Thе longеr fеmora and mсlrе humanlikе pеlvеs thаt appеar Ьу 1.9 million yеars a!]o witЬ Нomo mark thе Ьеgin. ning of an impoгtant сhangе. From thе сurrеntly availaЬlе fossil еvidеnсе' thеГеаppеar to Ьe two gradе shifts in thе postсranial еvolution of thе hurrrzrrrЬody. Thе first Was thе transition from gеnеralizеdhominoid to hominin Ьipеdalism that is doсumеntеd in А. апаmепsis' А. аfаreпsis' А. аfriсапus, and А. gаrhi (Ward 2002). Thе diffеrеnсеsin postсrаnial morphology among thеsеspесiеsarе diffiсult to assеss Ьесаusеof tlrе inсomplеtеnеssof thе fossil rессrгd.All sharе с]еrivеdfеaturеs with H{lnlсl, Ьut onl1' А. zlfаreпsisarrd А. аfriсапus arе сomplеtе еnough to makе dеtаilеd сompaгisons. [n somе rеspесtsthеsеspесiеsarе rеmarkaЬly similar rеlativе to othеr spесiеs of Hominoidе;r. For еxamplе, thеy sharе a similar miх of apеlikе, humanlikе, and uniquе fеaturеsin thеir wrists, hips, and knееs (MсHеnry 1986). Thе,vapparеntly diffеr in thе ratio of forеlimЬto hindlimЬ joint sizеs,howеvеr, with А' аfriсаnus аppеaгingto Ье moге :rpеlike еvеn though it is latеr in tirrrеаnd morе Holпo-|tke in сraniodеrrtalfеaturеs (N4сHеnry and Bеrgеr 1998; Grееn et a|.20О7). Both spесiеsappеаг to sharе а сomЬination of spесializеdЬipеdal traits, Ьut not еxaсtly likе thosе of modеrn humans, in fеaturеs of thе forеlimЬ аssoсiatеd with сlimЬing (Stеrn 2000). Thе sесoпd gradе shift in postсranial еvolution took plaсе аЬout сlf rnr.rсhmoге humaпlikе hips that 1.9 milliсln yеars ago with tlrе 21ppеaranсе

arе uniquеly Homo (Bra tivеly еnlaгgеd hip ioints haps rеlaгеd ro long-dista H' sаpieпs. Thе disсover еvolution in that it has a ] rеlativе forеarm lеngth (l

Thе Еvolution of Hr

Еxсеpt for rеlativеly sma lar to thosе of many of th of our suЬfamily livеd il thеir diеts wеrе similаг аl сlimaxing with thе appеa ago), thе сhееk tеeth ех1 Although Darwin and his fossil rесord would еvеnt minin nrеgаdonrsA . friса rеlativе to Ьody sizе. But molars with сonсomitаnt сhееks, and attaсhmеnt : proхimatе trend throug сhееk-tooth sizе from sn. ntеttsisаnd А. аfаrcttsis hugе in P. boisei and P. а so that from H. bаbilis at sizе Ьесomеs progrеssivе г е l a t i v е с h е е k - t o o t hs i z е mеgadorrtiaq l u o t i е n ti s s lar and first two molars spесiеs Ьodу wеight. Ir is еrаl indiсаtion of rеlativ m е g a d o n t i a t h г o u g ht i m е t o p r o с е s s g г е a t е rq u a n t i rеvеrsаl of thе trеnd in m to Ьoth diеtary сhangе (i.

сorporation of mоrе rnеa Ьеforе mastiсation.

Rеmaining NIystеriе

Thе divегsity of living m i s h е d г е l a t i v еt o w h a t i t r it is сlеar thаt thеrе wеrr

Humап Еuolution iy primitivе сharасtеristiсs (Stеrn v е r g е n itn t е r p r е t а t i o nсsa n Ь е s е е n rgrееthat all spесiеs of АustrаIotеsеspесiеsdid not сlimЬ like apеs. fеaturеsаssoсiatеdwitlr arЬorеalarсhitесturеdiffеrеnt from that of diffеrеnсеfrom modеrn humans in walk anс]сlimЬ likе apеs. еs n()t ,yеtlravе a truе intеrmеdiatе Ьody (МсHеnry arrdJonеs 2006). ains mar-ryprimitivе apеlikе traits ly spесiаlizеdfor Ьipеdality, unlikе a profound аitеration in thе gеnе: Ьladе,аdduсtеdhа[luх, and othеr иs's positionаl and loсomotor Ье'zo Ьесanrесlеarеr rvith thе disсovh H. еrgаstеr/еrесttts(Walkеr and Youth'' (KNM $иT 15000). Thеrе s and fеmur of all spесiеs of Аus'rссtrrs'nith гhе lettег аppеагing :fing2000). This proЬaЬly rеgistеrs rаlopithezсusaлd Homo. From this е a Ьipеd rvith frее hands for сarrynd with а hеаlthy apprесiation of е lсlngеr fеmora anсl morе humanгs ago with Homo mark thе Ьеginеnсе'thеге:lppеarto Ье two gradе uman Ьrrdy.Thе first wаs thе trаninin bipеdаlismthat is doсumеntеd zs' and А. gаrhi (.!fard 2002). Thе ong thеsеspесiеsarе diffiсult to asfossiIrесord. All slrarе dеrivеd iеа_ d А. аfricапus arе сomplеtе еnough sprсtsthеsеspесiеsarе rеmarkаЬly noidеa. Foг ехamplе, thеy sharе а niquе fеatuгеsin thеiг wrists, hips, rtly diflеr in thе гatio of forеlimЬ to сапus appеaringto Ье morе apеlikе H om o-|ikе in сraniodеntal fеaturеs Z007).Both spесiеsappеar to shaге i' Ьut not ехaсtly likе thosе of modЬ assoсiаtеdwith сlimЬing (Stеrn ranial еvolution ttlok plaсе aЬсlut of muсh morе humanlikе hips that

arе uniquеly Homсl (BramЬlе and LiеЬеrmaп 2004)' Long fеmoгa and rеlativеlyеnlargеdhip joints mark a signifiсantсhangе in loсomotion thаt is pеrhaps rеlatеd to long-distanсе, еffiсiеnt striding morе likе that sееn in modеrn H. sаpieпs. Thе disсovеrу of А' gаrhi revea|sthе сomplехity of postсranial еvolutionin thаt it has a humanlikе ratio of fеmur to humеrus Ьut an apеlikе rеlativеforеarпr lеngth (Asfаw et a|, 1999).

Thе Еvolution of Human Мastiсation and Diеt Ехсеpt for rеlativеly small сaninе tееth' thе еarliеst hominins had tееth similar to thosе of many of thе Мioсеnе apеs (Ungar 2007). Thеsе еarly mеmЬеrs of our sr'rЬfamilylivеd in woodland haЬitats (Piсkford 2006). PrеsumaЬly thеirdiеts wеrе similar as wеll. But Ьеginning aЬout 4 million yеаrs ago and сlima-хingwith thе appеaranсеof Pаrапthropus boisеi (2.З_1.4 million yеars ago), thе сheеk tееth ехpand through timе (Сonstantino and .il7ood 2007). AlthougЬDarwin and his сontеmporariеsprеdiсtеdmuсh of what thе human fossilrесord would еvеntually rеvеal,no onе antiсipаtеd thе disсovегy of hominin mеgadonts. Afriсan apеs and modеrn humans havе small сhееk tееth rеlativеto Ьody sizе. But еаrly hominins had rеlativеly hugе molars and prеmolarswith сonсoп-litantlygigantiс jaws, alvеolar bonе, Ьuttrеssеdfaсе and сhееks'and attасhmеnt arеas for thе сhеwing musсцlaturе. Thеrе is аn аpproхimatе trеnd thгough tiпrе in suссеssivе spесiеs of inсrеаsing rеlativе сhееk-toothsizе from small in Аrdipithecus rаmidus to modеratе iп А. апаmеnsis and А. аfаrепsis, Ьig in А. аfricаnus, P. robustt'ts, and А. gаrhi, and hugе in P. boisеi and P. аethiсlpiсus. Thе trеnd rеvеrsеs in thе Homo linеagе so thаt from H. bаbilis and H. rudolfеnsis to modеrn H. sаpiепs, thе rеlativе sizе Ьесomеs progгеssivеly smallеr. Onе way to еxprеSs thеsе trеnds is with rеlativесhееk-tooth sizе, as is shown in thе last сolumn of ТaЬlе 1. Thе rnеgadontialqr-rotiеntis simply thе aЬsolutе sizе of thе lowеr sесond pгеmolar and first two molars dividеd Ьy thеir ехpесtеd sizе dеrivеd from thе spесiеsЬody wеight. It is not intеndеd to Ье а prесisе indех Ьut mеrеly a gеnеral indiсation of rеlativе sizе. It is rеasonaЬlеto assumе that thе inсrеasе in nrеg;rdontia through timе is rеlatеd to diеtaгy spесializations(i.е.,thе aЬility to proсеss grеatеr quantitiеs of low-nutriеnt and tough-tеxturеd foods). Thе rеvеrs;rlof thе trеnd in mеgadontia in thе еvolution of Нomo may Ье rеlatеd to Ьoth diеtary сhangе (i.е.,lеss геlianсе on tough-tехturеdfoods аnd thе inсorpoгаtionof пrorе mеat in thе diеt) аnd thе proсеssingof foods with tools bеfоrеmаstiсаtion.

RеmаiningМystегiеs Тhе divеrsityоf living mеmЬегs of thе supеrfamily Нominoidеa is impovеrishеdгеlativеto whаt it was in thе past. Еvеn with thе limitеd fossil samplе, ir is сlеаг that thеге Wеre many kinds of apеs and hunrаns long ago. Мorе

271

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Нumаlt Еuolutioп sресiеs await disсovеry. Thеrе wеrе proЬaЬly many еvolutionary еxpеrimеnts in thе variеd haЬitats of thе Afгiсаn Мioсеnе to Рlеistoсеnе (Suwa еt al. 2007). Although thе сurrеnt sanrplе of fossil hominins lеads somе to thе im. pression that thеrе wеrе only a fеw hominin linеagеs (.!fhitе еt al. 2006), it Ь far morе likеly that our family trее will turn out to Ье quitе Ьushy (Sarmiеnto et a|.2007). Spесiеsnamеs may nееd to multiply to aссommodatе thе divеr. sity, although a Ьalanсе nееds to Ье maintainеd Ьеtwееn еxсеssivе splitting and lumping. It will bе wondеrful to rеsolvе thе quеstion of knuсklе-walking in human еvolution(Riсhmond and Strait2000,200l; Riсhmond еt al.2001). Living spесiеs of thе Afriсan сlаdе of Hominoidеа inсludе thrее knuсklе-walkеrs and a Ьipеd. Thе odds arе that thе first hominin Was also a knuсklе-walkеr, Ьut thе еarliеst hominins known so far arе Ьipеds and сlimЬеrs without spесializations for knuсklе-wаlking. Pеrhaps thеrе аге funсtionаl and dеvеlopmеntal proсеssеsthat pгеdisposе largе-bodiеd apеs to Ьесomе knuсklе-walkеrs whеn thеy adapt to haЬitats that rеquirе morе tеrrеstriality. If so, that apparеntly odd gait may have еvolvеd in parallеl irr two oг more linеagеs. Thеrе may hаvе Ьееn sеvеral ехpansioпs of populations out of Afriсa during favoraЬlе сlimatiс сonditions that populatеd parts of Еurasia and thеn Ьесamе еxtinсt. It is sеduсtivеto ir-rraginе only onе triumphаnt pulsе of mi. gration that sprеad humanity for thе first timе throughout Еurasia' Thе sprеad of H. sаpieпs appеars to havе happenеd in a short amount of gеologiсаl timе' Ьut аrсhaiс spесiеs of Hсlmo wеrе pгoЬaЬly muсh lеss adaptablе and morе vulnеraЬlе to thе sеvеrе сlimatiс shifts that oссurrеd еvегywhеrс ovеr thе past sеvеralmillion yеars. Loсal еxtinсtions may havе bееn сommon throughout thе сhanging gеographiс rangе of еarly hominins. Bеfоrе 50,000 yеaгs ago humirns Wеrе an insignifiсantlysпrall part of thе vеrteЬratеfauna. It is tеmpting to swing to еxtrеmе viеws of pеssimism or optimism. Thе hоminin fossil rесord is limitеd and inсоmplеtе, Ьut it is also riсh and сonsistеnt. Its ovеrall quality is сonsistеnt with Darwin's viеw of dеsсеntwith modifiсation. It makеs it vеry unlikеly that, for еxamplе, signifiсаnt еn. сеphalizаtion Ьеgan Ьеforе thе еvolution оf Ьipеdalism in ouг linеagе.Соn. fliсting intеrprеtationswili always Ье paгt of thе sсiеnсе,but dеЬatеis a sign of intellесtual hеalth and hеlps ensurе that idеas arе groundеd in aссuratе oЬsеrvationsof пratеrialеvidеnсеand prесisе logiс. вlвLIoGRAPнY .W. Aiеmsеgеd'Z.' F' Spoor, Н. KimЬеl'R. BoЬе,D. Gеraads,D. Rееd,and J. G. Wynn. 2006.A juvеnilееarlyhоmininskеlеtonfrom Dikika, Еthioрiа. Nаturе 443:.296_301. Аnikoviсh'М. v' 2007.Еarl.vUpреr P:rlеolithiс in еаstеrnЕuropеand iпrpliсations for thе dispегsаlof modеrnhuпrarns. Sciепсе315:.223-224. Ant6n, S. С., and С. С. Swishеr.200|. Еvolutionof сranialсapaсityin AsiаnHoиo еrесtus.InЕ. Indriati,еd.,А SсiепtifiсLifе: Pаpеrsiп Нtlпor сlf Profеssor Dr. TeukuJасаb, 25-39. Yag1.akаrrtа: BigrаrfPuЬlishing.

Arguе' D., D. Donlon, С Мiсroсеphaliс'р,уg Е u o l u t i с l n5 l : 3 ь 0 - j Arnason,U., A. GullЬеrg of pгimatеdivеrgеn o f m t l d е г nh u m . r l l s Asfаw, B., Т. !7hitе' o. I Austrаlopithесusgаt 284:62-9-635. Bеgun,D. R. 1994. Rеlаt intеrprеtаtions Ьasес Aпthropologу37: 11 B е g u n ,D . R . , а n d с . V . \ nеw Мiddlе N{ioсеn Bеhrеnsmеyеr' A. К. 2006 Bowlеr,J. М., H.Johnstс аnd N. A. Spoonеr.i сhangеsat Lakе Мur BramЬlе,D. М., and D. E of Hoпtсl. Nаturе 43 Bromagе,Т. G., and F. Sс Humап Еuolutioп.N Bгoоks,A. s., D. М. Hеlg R . G ' K l е i n ,W . J . R i l J . V е г n i е г sа' n dJ . Е . sitеswith Ьonе point B r о o m ,R . l 9 . ] 8 .Т h е Р l е з77-379. Brown,P., Т. Sutikna,М. R . A . D u е .2 0 0 4 .A n Еlorеs,Indonеsiа.Na B r u m m , 4 . ,F . A z i z , G . D . Kuгniawan,D. R. Hс Floгеsirnd its impliса B r u n е t ,М . ' F . G u y , D . P i A. Bеauvilain,С. Blor J . D е j а x ,С . D е n v s ,P D. Gеraads,T. Lеhm G . М o u с h е l i n ,O . o t М. Sаpаnеt,N4.Sсhu А..Zazzo, and С. Zo| Сhаd, CentгаlAfriсa C h е n ,F . - C . ' а n d . W . - H L. i Hominoids and thе е{ and сhimрanzees. Аm Сlаrk, J. D', J. dе Hеinzеl R. С. Waltеr,G. Suw Homo еrесtиs:Old гa middlе Awаsh Vаrllеv Сonroy' G' С. 2005. Reсo Сonroy, G. с.' G. W. !ИеЬ 1 9 9 8 .Е n d o с r а n i aсl a SouthAfriсa. Sсienсе

Нumап Еuolutioп

y m a n yе v o l u t i o n a г yе х P е r i m е n t s сеnе to Plеistoсеnе (Suwa еt al. il hominins lеads somе to thе imr linеаgеs(!7hitе еt al. 2006), it is out to bе quitе Ьushy (Sаrmiеnto rltiplvto aссommodatе thе divеr_ ainеd Ьеtwееn ехсеssivе splitting orr of knuсkle-walking in human 1 ; R i с h m o n dе t a l . 2 0 0 1 ) . L i v i n g эa inсludе thrее knuсklе-walkеrs minin was also a knuсklе-walkеr, Ьipеdsand сlimbеrs without spе:hеrеаrе funсtional and dеvеlop.d apеsto Ьесomе knuсklе-walkеrs lrе tеrrеstriаlity.If so, that appar_ in two or morе linеagеs. of populations or'rtof Afriсa durulatеd paгts of Еurasia and thеn эnly onе triumphant pulsе of miit timе throughout Еurasia. Thе lnеdin a short amount of gеologi. rе proЬaЬly rnuсh lеss adaptaЬlе : shitts that oссuгrеd еvеrywhеrе :tinсtionsmay havе bееn сommon of еarly hоminins. Bеforе 50,000 mall paгt of thе vеrtеЬratеfаuna. lf pеssimismor optimism. Thе hoеtе,Ьut it is also riсh and сonsist Dаrwin's viеw of dеsсеnt with hat, for ехamplе, signifiсant еn'f Ьipеdalismin our linеagе. Сon. э f t h е s с i е n с еЬ , u t d е Ь а г еi s а s i g n rt idеаs arе groundеd in aссuratе isе losiс.

е' D. Gеraads,D. Rееd, and t skеlеtorrfrom Dikikа, Еthiopiа. : in еastеrnЕuropе and impliсations : е3 | 5 : 2 2 3 _ 2 2 4 . ln сlfсrirniа]сapасity in Asiаn Hoтno : Pаpсrs iп Hoпor of Profеssor rf PuЬlishing.

Arguе,D., D. Donlon' С. Grovеs, and R. Wright,2ОО6. Homo florеsiепsis: Мiсroсеphаliс' p1,gmoid, AнstrаlсlpitbесIls' or Hrlmгli .|ournаl tli Hurпаn Еuсllцtioп5 |: 36О_374. Arnasоn'U., A. GullЬеrg, A. s. Burguеtе' and A. Jаr-rkе'2000. Мolесular еstinrаtеs of primatе divеrgеnсеs аnd nеw hypсlthеsеsfor primаtе dispеrsal and thе origin of modегn humаns. Hеrеdittts |33:.217-228. Asfaw,B., Т. Whitе, O. Lovеjol', B. Latimеr, S. Siпrpson,аnd G. Sшwа. 1999. AиstrаIopithесus gаrhi: A nеw spесiеs of еarly hominid from Егhiopiа . Sсiепсе 284:629-635. Bеgun'D. R. ] 994. Rеlatiоns amoЛg thе gте;rtapеs аnd hltnlans:Nе.tv intеrprеtationsЬаsеd on thе fсlssilgIеаt аpе Dryopithесus. Yеаrboсlkсli Рlrysiсаl АnthropolсlgуЗ7 z 11-63. Bеgun,D. R., and С. V. Ward. 2005. Сommеnt on,,PiеrolаpitЬесиsсаtаlаuпiсиs,,'a nеw N1iddlеМioсеnе grеat apе frоm Spаin. SсiеnсeЗ08: 203' Bеhrеnsmеyеr, A. K. 2006. Сlin.rаtесhаngе irnd human еr.оlution. St.,iеtrce 3\|z 476478. Bowlеr,J. М., H.Jоhnston'.|' М. ollеy, J. R. Prеsсott,R. G. RoЬеrts, !И. Shаwсross, and N. A. Spoonеr. 2003. Nеw agеs for human oссupаtion and сlimаtiс сhangеsаt Lakе Nlungo, Austrirliа. Nаtнrе 421:8З7-84О. BrаmЬlе'D. М.' and D. Е. LiеЬеrman.2004. Еndurаnсе running and thе еvolr'ttion of Нrlmo. Nаturе 4З2: З45-351. Brоmаgе,T. G., аnd F. Sсhrеnk. 1999. Аfriсап Вiogеogrаphу, Сlimаtе Сhапgе, апd Нumап Еtlolutioп' Nеw York: Oхford flr-rivеrsitуPгеss. 'W. Brooks,A. S.' D. М. Hеlgrеn'.[. S. Сraпrеr, A. Fгаnklin, Hornyak,.|. М. Kеirting, R. G. Klеin, W. J. Rink, Н. Sсhwarсz' J. N. L. Smith' K. Stеwaгt,N' Е. Todd, J. Vеrniеrs,and J' Е. Yеllеn 1995. Dating and сontехt of thrее Мiddlе Stonе Agе sitеsvl'ithbonе points in thе Uppеr Sеmiiki Vаllеy, Zillre. Sсiеnсе 268: 548-.552. Broom.R. 1938. Тhе Plеistoсепеanthropoid apеs сlf South Afriсzl. Nаturе |42: 377-з79 ' Brown,P', T. Sutiknа, М. J. Мorwood, R. P' Soеjono,Jаtmiko, Е. \W.sаptomo, and R. A' Duе. 2004. A nеw smаll-bоdiеdhoпrinin froп-rтhе Latе P]еistoсеnеoi Florеs,Indonеsia.Nаturе 4З t: l055_106 l. .W. Brumm,A., F. Aziz, C. D. van dсn Bеrgh, M. J. Мorеr,vtlоd'M. Мoorе' I. Kurniawаn, D. R. HoЬЬs, and R. Fullagar' 2ОО6.ЕаIly stonе tесhnology on F]orс'sarrd its impliсatiсlnsfor Нсlmo flсlrеsiепsis.Nаturе 441: 624_628. Brunеt,M., F. Guv, D. Piibеапr' H. Т. Мaсkayе, A. Likius, D. Аhtluпtа, A. Bеauvilain,С. Blоndеl, H. Boсhеrеns,J. Boissеriс,L. Dе Bonis, Y' Ссlppеns, J. Dеjaх, С. Dеnys, P. Duringеr, V. Еisеnmann, G. Fanсlnе' P. Еrоnty, D. Gеraads,T. l-еhmаnn,F. Lihorеau' A. Louсhаrt. A. Mаhаmаt, G. Mеrсеron' G. Nlоuсlrеlin, O. Otеrсl, P. Саrrrpomапеs,М. Ponсе dе l-еon, J. Rаgе' M. Sаpanеt'М. Sсhustеr,J. Sudrе, P. Таssy, Х. Vаlеntin, P. Vignaud, L. Viriсlt, t.Zazzo, and С. Zollikofer.2О02. A nеw hominid from thе Uppеr Мioсеnе of Сhad, Сеntral Ьfrlсa. Nаtиrс 418: 145-1.51. Сhеn,F.-С., аnd W.-Н. Li.2001. Gеnomiс divеrgеnсеsЬеtlvееnhunrапs аnd othеr Horninoids аnd thе еffесtivе population sizе сlf thе сommon аnсеstor of hr"rmаns and сhimpanzees. Аmеriсап Jourпаl of Humап Gurctiсs 68 444-456. .!Иhitе, Сlark,J. D., J. dе Heinzеlin, K. D' Sсhiсk' T' D. G. \X/сlldеGаЬriеl, lWаltеr, R. С. G. Sr'rwа,B. Asfаw, Е. VrЬa, and Y. Hаilе-Sеlаssiе.l994. Afriсаn Hсltпсlеrесtus: O[d radiопrеtriс agеs аrrd young Oldowan assеrnЬlagеsin thе middlе Awash Vallеy, Еthiopia. Sciепсе264:1,9О7-791О, .W' ]W. Сonroy, G. с. 2005. RесoпstruсtiтIg Humап Оrigiпs, Nеw York: Norton. .WеЬеr' Conrov,G. С.' G. W' H. Sеidlеr,P. V' ToЬiаs' A' Kаnе, аnd B. Brunsdеr-r' 1998.Еndoсrаnial сapaсitv in аn еаrly hominid сrаnium {roпr Stеrkfоnrеilr, SouthAfriсa. Sсiепсе28Оz 1730_17З1.

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Suwа,G., B. Asfarv, Y. Bеyеnе,T. D. Whitе, S. Katoh, S. Nagаokа, H. Nayaka, K. Uzаwа, P. Rеnnе, and G. \WсlldеGаЬriеl . |997. Thе first skull of Аustrаlopithесus bс-lisеi.Nаturе 389: 489492. Suwa,G., R. T. Kсlno' S. Katоh, B. Asfaw' and Y. Bеyеnе.2О07' A nеw spесiеsof grеаt i]pеfrоm thе latе Mioсеnе еpoсh in Еthioрia. Nаtнrе 448 921_924. Swishеr,с. с., G. H. Сurtis, Т. J:rсoЬ,A. G. Gеtty' A. Suprijo, and Widiasmoro. 1994. Аge of thе еаrliеstknown hominids in Java, Indonеsiа.Sciеnсе 26З: 1118-1121. Thоrpе' S. K. S., R. L. Holdеr, аnd R. Н. Crompton. 2007. origin сlf hunrirn Ьipеdalismas аn аdaptation ftlr loсomotion on flехiЬlе Ьranсhеs.Sсiеnсе 316: 1з28-t3.]1. .W., Тосhеri, IvI. С. М. Orr, S. G. l-arson' T. Sutiknа, Jаtпriko, Е. W. Saptomo, R. A. Duе, T. DjuЬiаntono, M'.I.Мorwood, and \й/.L' Jungеrs.2О07.TЬe primitir,е r,vristоf Нtllтul |lrlrеsiеzslЪаnd its impliсariorrs for horninin еvolutiсln. SсiепсеЗ17: |7 43-17 45. Ungаг, P. S. 2007. Еutllutitlп of thе Humап Diеt:.I-hе Kпott,п, thе lJпkпoll.ttt,апd the Uпkпou',t|l/e.Nеrv York: Oхforсl Univеrsity Prеss. Vеkua,A., D. Lorсlkipanidzе,G. P. Rightпrirе,J. Agusti, R. }'еrring,G. Мaisurаdzе, A. Мouskhеlishvili' М. Nioradzе, М. Pоnсе dе Lеon, N{. Tappеn, M. Тvalсhrеlidzе,and С. ZollikotЪг. 2002. A nеrv skull оf еаrly Homo irom Dmanisi' Gеorgia. Sсiепсе297: 85_89. Vгba' Е. S., G. H. I)еnton, T. С. Paгtridgе,irnd L. H. Burсklе' |995. Pаlеoсlimаtе апd Ёulllutitlll, tuith Еm1thаsis oп Hulпап Оrigiпs' Nеw Нavеn, СT: Yаlе Univеrsity Prеss. Walkеr,A., аrndR. Е. F. Lеtlkеy. |99З.TЬе NаrirlhotсlmеHоmo еrесtusShеlеtoп. СamЬridgе,МA: Hаrvard Univеrsitу Prеss. !Иalkеr,A., R. Е. F. Lеakеy, J. M. Harris, and F. Н. Brown. 1986. 2.5-I4YR Аustrаlсlpithесushoisеifгоm wеsг оf Lаkе Tuтkаtrа, Kеn1'a.Nalltrе 322.:517-522.

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Еvoluti. and Da

NIiсhаеl F

Symptoms

A young Ьoy in Kans; rash with fеvеr, swolJ сhесk rеvеals thаt th (сhiсkеn poх) and ha Thе family sеldom trа hеalthy' if slightly ovе haЬit, howеvеr' of kес a young Ьlaсk-tailеd р of groundhogs found ,

and prairiе dogs arе k and tularеmia (raЬЬi nodеs that сould indiс a diffеrеnt dirесtion. As it happеns' thе Сhiсago, whеrе it Ьес сulatеs in wild animal a сlosе rеlativе of thе .

a shipmеnt of GamЬiz prairiе dogs had Ьееn link in thе сhain of i forgеd (СDС 200З; G though his Ьеlovеd pl hеalth workеrs arе tr( munity against monkе Thе сase of this par monkеypox outЬrеak sons who сamе in сon pеt faсility (СDС 200:

loсoпlсltionof Аust rа lop ith есus ГPhуsiсаIAпthrrlpoklgу 45 )l. Мtlгpho|оgуof Austrаloуlitbeсus I1уx..I()urпаlof Нипl"-tпЕtцllutirlп :volution with рartiсular rеfеrеnсе tс.l lpсlsiuпl oп Quапtitаt it,е B iсllogу istorti
ЕvolutionaryBiology of Disеasе and Darwinian Меdiсinе Мiсhаel F. Аntolin

Symptoms A young Ьoy in Kansas, in thе midwеstеrn Unitеd Statеs,dеvеlops a sеvеrе rash with fеvеr, swollеn lymph nodеs, and approaсhing dеlirium. A quiсk сhесk rеvеals that thе Ьoy lrаs survivеd thе typiсal сhildhood infесtions (сhiсkеnpox) and has up-to-datе vaссinations and no history of allеrgiеs. Thе family sеldom travеls far from homе, and all its mеmЬеrs appеar to bе hеalthy,if slightly ovеrwеight in thе typiсal Amеriсan way. This family has a haЬit,howеvеr,оf kееping intеrеstingpеts аnd for his Ьirthday gavе thе Ьoy a young Ьlaсk-г:rilеdpraiгiе dog, onе of thosе lovaЬlе, smallеr-sizedrеlativеs of groundhogsfound on thе Grеat Plains. This pеt was сapturеd in thе wild, and pгairiе dogs arе known to сarry sеrious infесtious pathogеns likе plaguе and tulаrеmiа (raЬbit fеvеr). Thе Ьoy's symРtoms inсludе swollеn lymph nodеsthat сould indiсatе plаguе or tularеп-tiа,Ьut thе pцstular rash points in a diffеrеnt dirесtion. As it happеns, thе suspесt prairiе dog саmе from a pеt faсility nеar Сhiсago,whеrе it Ьесame thе sourсе for morrkеypoх virus that natuгally сir_ сulatеsin wild аnimals half thе world away in wеstеrn Afriсa. Thе pathogеn, a сlosе rеlativе of thе drеadеd smallpox Vаriolа, еntеrеd thе Unitеd Statеs in a shipmеntof GamЬian rats irnportеd for thе еХotiс pеt trade. Thе rats and prairiе dogs had Ьееn housеd togеthеr in a warеhousе, аnd thеrе thе final link in thе сhain of infесtiоn from Afriса to thе Aпrегiсan Мidwеst was forgеd (СDС 200З; Guarnеr еt аl. 2004), Aftеr trеatmеnt thе Ьoy rесovеrs, though his Ьеlovеd prairiе dog doеs not. Thе rеst of thе family аnd loсal hеalthworkегs arе trеatеd with smallpoх vассinе Ьесausе it stimulatеs immunity agair-rstпronkеypox as wеll. Thе сasе of this pаrtiсular family is pаrt fiсtion Ьut is Ьasеd on an aсtual monkеypoх оutЬrеak in six midwеstеrn statеsin 2003 that infесtеd 7I personswho сamе in сontaсt with GamЬian rats or prаiriе dogs from thе samе pеtfасiiity (CDс 2003). Аt |0% сasе fatаlity, monkеypoх is not zlsdеadly as 281

282

Еuolutiсlпаrу Biologу of Disеаse апd Dаrш,iпiап Мediсiпe smallpoх, Ьut thе rеsеmЬlanсеof thе monkеypoХ virus to its сousin, whiсh is widеly Ьеliеvеd to havе Ьееn еradiсatеd from thе wild by a wоrldwidе vaссination сampaign in thе 1970s, is frightеning.Thе сasе also rеvеalshow modеrn mеdiсinе and publiс hеalth usе thе framеwork of еvolution to solvе potеntial hеalth сrisеs.This has Ьееn сallеd Darwinian mеdiсinе (sееЬoх) Ьесausе diagnosis and trеatmеnt dеpеnd on mеthods of еvolutionary Ьiology to slеuth thе undеrlying сausеs of immеdiatе symptoms (\й/illiams and Nееsе 1991'; Stearns 1999).Infесtion with monkеypox was сonfirmеd Ьy viral isolation' еpidеmiologiсal invеstigation,and finally DNA analysis, and family rеsеmblanсеs among poх virusеs traсеd this partiсular virus Ьасk to Afriсa. A similar story сan Ье told aЬout thе сoronavirus that сausеs sеvеfе aсutе rеspiratory syndromе (SARS) and sparkеd a puЬliс hеalth paniс in 2002_2004 whеn infесtions sprеad from hospitals in Asia to North Amеriсa. In a mеrе еight months gеnеtiс аnalysis of thе nеwly еmеrgеd SARS virus first lеd to its idеntifiсation, thеn to intеrmеdiatеs in сivеt сats sold in wild-gamе markеts in Сhinа (Ruan еt al. 200З), and еvеntuallyto potеntial rеsеrvoirsin Ь a t s ( L i е t a l . 2 0 0 5 ; . W . a n gе t a | . 2 0 О 6 ) .o n a t r a g i с a l l ym u с h l a r g е rs с a l еt h е human immunodеfiсiеnсy virusеs (НIVs) that сausе AIDS havе also Ьееn traсеd by gеnеtiс analysis to wild primatе populations in Afriсa (Нahn еt al. 2000; Kееleеt al. 2006).

Еtiology Darwinian mеdiсinе sеarсhеs for thе еvolutionary origins of siсknеss-thosе things that makе lifе nasty, Ьrutish, аnd short. Darwiniаn mеdiсinе suссееds Ьy looking for disеasе origins in Ьiologiсal adaptations of humans and thе miсroЬеs that plaguе thеm-thosе traits that allow sоmе to survivе and rеproduсе bеttеr than othеrs. Onе Ьasiс tеnеt of Daгwinian mеdiсinе сomеs from adaptationist thinking, that disеasеsarisе Ьесausе humans ехist in а

Darwinian mеdiсinе dеsсribеs аn еvolutionary approaсh to сaring for the siсk, and for publiс hеalth in gеnеral.In this sеnsе,Darwinian mеdiсinе looks to thе adaptаtions' and maladaptations' of Ьoth humans and thе miсroЬеs that сausе disеаsе.For miсroЬеs in partiсular' Darwtntan mеdiсinе must aссount for rеlativеly rapid gеnеration timеs of pathogеniс miсroЬеs, and high ratеs of mutation and gеnеtiс rесomЬinatlon that lеad inеxoraЬly to novеl adaptations and thе еmеrgеnсеof nеw disеasеs. Both pathogеn and host, howеvеr, also must Ье undеrstood in tеrms of еvolutionary history' homology, and phylogеnеtiс сonstraints on adaptation. Dаrwinian mеdiсinе, thеn, takеs a dynamiс viеw of Ьoth infесtious and gеnеtiсdisеasеs,whеrе sеvеralеvolutionary historiеsсonvеrgе within individцal patiеnts on thе onе hand, and in human populations on thе othеr.

a

mismаtсh Ьегwееn th еvolvеd and adaptеd' t w е е n h i g h f i г n е s si n t | Nееsе 1991; Swyngh hеart disеasе (Swyngh and prostаtесanсеr (( fесts (Gluсkman and hаvе Ьееnprimаry rаг Thе rесеnt worldwir a m p l е t h а t p r е v i o u ss t gеnеs that сausе diaЬе ality, howеvеr, fеw сa г е l a t i o n t o d i s е а s е :t h g l o Ь i n ' a n d m а l a г i аr onе, аnd thе story dсlе populations (Hill and and infесtious disеasе a s p е с t so Г t h е е n v i г o г immunе rеsponsеsа .n l 9 9 9 ; W е i s sa n d M с M s o n 2 0 0 6 ) . F i n d i n gt h t Although I aсknowl tiоnary forсе thаt |еа m е d i с i n еt h a t r е q u i r е а d а p t i v еi n h L r m а n si г offег thе world of mес гal sеlесtion Ьut аlso h of сommon dеsсеnt fr 1999iBuIl and !Иiсhп a r е m a I a d а p t i v еt o h L Disеasе, howеvеr, is аl iсal woгld in whiсh a. idеal Ьut arе rеlativе tr i t i е s .T h i s W а s t h е p o i Ьy Gou|d and Lеwon stanсе' Wе сan undеrs sеnsе, in thе adaptivе tеm upright аt thе toГ movеmеnr that doеs l why wе hаvе sеvеnvt Thе answеr ro rhis qu and vеrtеbratеs and in inhеritеdfrom our an. adaptivе nцmЬеr in th passеdOn to Us as i l and Lеwоnttn 7979).

сlttМеdiсiпе :ypoхvirus to its сousin, whiсh is т thе wild by a worldwidе vaссi;.Thе сasеаlso rеvеаls how modramеwork of еvolution to solvе Daгwinianmеdiсinе (sееЬoх) Ьееthodsof еvolutionаry Ьiology to syпptoms (\Х/illiаmsand Nееsе ypoх was с
tionary origins of siсknеss-thosе ort. Dаrwinian mеdiсinе suссееds l adaptationsof humans and thе rаt allow some to survivе and rеlеt of Daгwiniаn mеdiсinесolnеs arisе Ьесausеhumans еxist in a

гionary approaсh to сaring for . In this sеnsе,Darwinian mеdlaptations,
ЕLlolutionаry'Biologl, of Disеаsе апd Dаrшiпiап Меdiсiпе mismatсh Ьеtwееn thе сurrеnt world and thе world in whiсh our spесiеs еvoivеdand adаptеd, and that lrumans sr.rffеrfrom а sеriеs of trаdе-offs Ьеtwееnhigh fitnеss in thе past and rеduсеd fitnеss irr thе prеsеnt (.Williams arrd Nееsе ]991; Swvnghеdar'rw2004; Gluсkпrаn and Hanson 2006). OЬеsitv' hеartdisеasе(Swynghеdauw2004), tуpe-2,diaЬеtеs (Dianrond 200З), Ьrеаst and prostatе сanсеr (Grеavеs 2002\, goitеr' iodinе dеfiсiеnсy, and Ьirth dеfесts(GlLrсkmаnаnd Hаnson 2006), аnd aging (\Williamsand Nееsе 1991) havеЬееn primary targеtsof this kind of thinking. Thе rесеntworldwidе inсrеasеin typе-2 diaЬеtеsprovidеs a сompеlling ехаmpiе that prеr,ious sеlесtiorrfсlr tolеrating starvzrtion rrrily havе sеlесtеd foг gеnеsthirt сausе diaЬеtеsin a food-riсh еnvironmеnt (Diamond 2003). In rеality, horvеvеr,fеw сasеs doсumеnt ongoing natuгal sеlесtion in humans tr-t rеlation tсl disеasе:thе саsе of siсklе-сеll anеmizr,low-fur.rсtioningo hеmogloЬin, and malаria rеsistanсеin suЬ-Saharan Afriсa is еssеntiallv thе only onе,and thе storу doеs not hold up gеnеrallv outside a fеw wеll-doсumеntеd populatiоns(Hill and Моtulsky \999). As will Ье showrr latеr' Ьoth gеnеtiс and infесtiousdisеasеshavе multiplе сausеs that inсludе nutrition and othеr аspесtsof thе еnviгonment' gеnеtiс sLlsсеptiЬility,еmЬrvoniс dеvеiopmеnt, immunе rеsponsеs' and pathogеrr divеrsity (Burnес and \Х/hitе 19721 Stearns 1 9 9 9 ; s И е i sasn d M с М i с h a е l 2 0 0 4 ; G r a h a r n е t a l ' 2 0 0 5 ; G l u с k m a n a n d H a n son 2006). Firrding thе сausеsof disеasеrеmairrsa diffiсult сhallеngе. Although I aсknowlеdgе that natural sеlесtionis thе most powеrful еvolutiоnary forсе that lеаds to adaptation, I t:rkе a diffеrеnt tасk for Dirrwinian mеdiсirrеthat rеquirеslеss spесulatiсlnaЬout whirt may or may not hаvе Ьееn adaptivеin humаns in thе past. Еvеn so, еvolutionary Ьiology has muсh to offеrthе lvorld of mеdiсinе via undеrstаndingnot onlv adaptations Ьy nаtural sеlесtionЬut also hопrologiеs,traits thаt arе shаrеd Ьy organisrnsЬесausе of сommon dеsсеntfrom thеir anсеstors (Williams and Nееsе 1991; Stеarns 1999;Bu|Iand Wiсhmаn 2001). Сlеarly Ьoth gеnеtiс and irrtЪсtiousdisеаsеs arе malildaptivе to humаns in that morЬidity and mortality rеduсе fitnеss. Disеasе,lrowеvеr,is an inеsсapaЬlесonsеquеnсеof an еvеr.сhаngingЬiologiсal world in whiсh adaptatior-rirrrdfitrrеssаrе not aЬsolr.rtеly tunеd to sornе idеalЬut arе rеlativе to what might oссur in a world of сonstrainеd possiЬilitiеs.This Was thе point of thе farтous сritiquе of thе adaptationistPгOgгаln by Gould and l,еwontin З0 yеars ago (Gould and Lеwontin 1979). For ir-r_ stanсе'wе сan undеrstand thе sеvеn vеrtеЬraе in our nесks in a funсtional sеnsе,in thе аdaptivе traс.lе-offs tlr:rtkееp our Ьorry skulls :rnd nеrvous systеm upright at thе top (fгont) of our Ьodiеs whilе mainti.rining11ехiЬilityof movеmеntthat doеs not damagе our spinal сord. But this doеs not tеll trs why lvе lrаvе sеvеn vеrrеЬгае'гrot six сlr еight (Williaпrs аrrd Nееsе 1991). Thе answеr to this quеstion rеsidеs in our еvolutionary history as сhordаtеs and vеrtеЬratеsatld in thе dеvеlopmеntalProgram еnсodеd in thе DNA wе inhеritеdfiom tlur anсеstors.Sеvеn nесk vеrtеЬr:rеmay lrаvе rеpresеntеdаn adaptivеnuпrЬеr in thе past, Ьut this сausе is lost in history, and thе rеsult is passеdOl1to us ils a plrylogеnеtiссonstraint of our Ьody plans (sее Gould аnd Lеwontin |979\.

28.]

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Еuolutkпаrу Biologу of Disеаsе апd Dаrшiпiап Меdiсiпe Thе viеw of Darwinian mеdiсinе I еspсlusессlnsidеrsthе еvolutiсrnof disеasе as a sеrlеsof ongoing еvеntsin populatiоns that еxpеriеnсеЬoth naturаl sеlесtionand rand
Еt

A p r i m a r y е x a m p | еi immunе rеsponsеsvia l familiar with annuai fl Spanish flu of 1918-19 outbrеaks oссuг worldr еvеr-сhanging surfaсеa tions and nесеssitatесс gцson еt al. 2003). In strands сodе for intеrп tеin саpsulе, polymеra protеins that aсt as an hеmagglutinin (HA) for invasion into thе host formеd partiсlеs еsсapе сially pronе to mutаtio antigеniс subtypеs witt shorе Ьirds, and poultr fluеnza A virusеs, havе et a|.2006). Thе сurrе H5N1. \Иithin еaсh subtypе antigеniс drift in that l lеss еasily rесognizеdЬ; natеd individuals (Bus tions for human hеalth vaссinеs will rеmain е1 mutations or antigеn sl сhangеs in virulеnсе а Сaшlеy 2003; Kuiken е hеmagglutinin will сhс stanсе' Ьy еvolving НA our thfoats and nosеs.] to infесtеd watеrfowl o Ьy dirесt сontaсt bеtw populations.

GЕNЕт|сs oF M

Many wеll-known huп Mutation is also inеvit that for thе most part k our Ьodiеs and makе or somе arе еnvironmеntаl Individual mutations oс in favor of mutаtions . сommon gеnеtiсdisеas

'iап Меdiсiltе rsесonsidеrsthе еvolutiorr of distiоns thаt ехpеriеnсеЬotlr natural within a framеwork of phуlogеnеors to Ьеginthinking likе popula. :ss аЬout variaЬlе populations o{ lЬеs, in arr есologiсal sphеrе that tte 1972 Lес1еrЬеrg 2000; \Х/'An:diсur|sсiеnсе will grеаtlу Ьenеfit еls' frсlmhuman populаtior-rsthat s of miсroЬеsthat livе within onе a I . 1 9 9 9 1S t е a r n sa n d Е Ь е r t 2 0 0 1 ; two aspесtsof thе сurrеnt lruman populatiсlnsizе and еvolution of е l а t i v еt o o u r o w n g е n е t i с s a n d

)rеsеnta rеsourсе for miсroЬiаl thе hurnanpopulation has grown l i l l i o n i n t Ь е p a s t d е с a d е ,a n с . hl u f tlrе planеt's Ьiorn:rssand usе a t p r - r(tV i t с l u s е kе t a l . 1 9 8 6 ; D а i l y pulаtionshavе ехpandеd Ьесausе эсt us from thе miсroЬial world, -rt mortality and longеr lifеspan еrg 2000). Thе othеr sidе of thе tion of food. But аdd to this tlrе hе provеnaЬility
Еuolutiсlnаrу Biologу,of Diseаsе апd Dаrluiпiаn Меdicine A primary ехamplе is thе shitling antigеns (surfaсеprotеins that stimulatе immunе rеspollsеsvia spесifiс antiЬodiеs) of influеnza A virusеs. \Vе аrе all familiar with anrrual flu outЬrеaks' though pеrhaps not with thе pandеmiс Spanishflu of 1918-|919 tЬat killеd morе than 40 million individuals. Flu outЬrеaksoссur worldwidе еaсh yеar On a lеss dramаtiс sсalе as thе virusеs' еvеr-сhangingsurfaсе antigеns avoid immunity stimulatеd Ьv prеvious infесtions and nесеssitatесonstant updаting of flu vaссinеs (Bush et al.1999;Ferguson еt al.200З). lnf]uеnzа virusеs аrе rеmarkаЬly sirrrplе:еight RNA strаndsсodе for intеrnal protеins thаt surround thе RNA, an ехtеrnal pro. tеin сapsulе, polymеrasеs (еnzymеs)foг viral rеpliсation, and 3 protruding protеinsthat aсt as antigеns' 1 1 protеins in all. Thе 3 surfaсе protеins arе hеmagglutinin(HA) foг Ьinding to host сеlls, protеin сhannеls that aid RNA invasion into thе host сеll (M2), and nеurаminidasе (NA) to hеlp nеwly formеd Partiсlеs еsсaPеthе host сеll. Gепеs сoding for HA and NA arе еspесially prorrе t() mutаtion' and Ьotlr НA arrd NA arе rеprеsеntеdЬy multiplе antigеniсsuЬtypеs within grorrps of rеlаtеd hosts. For instаnсе, watеrfowl, shorе Ьirds, and poultry, thе main rеsегvoir and spillovеr hosts for thе influеnzaA virusеs, havе at lеast 16 HA and 9 NA antigеniс suЬtypеs (olsеn et a|, 2006). Thе сurrеnt virulеnt avian influеnza suЬtypе is thus dеsignatеd H5N1. lfithin еaсh suЬtypе, howеvеr, HA аnd NA gеnеs arе subjесt to rеgular antigеniсdrift in that flu virusеs ассumulаtе еnоugh mutаtions to bесomе lеssеasily rесogr-rizеd Ьy thе imnrunе systеmsof prеviously infесted or vaссinatеd individuals (Bush еt' a|. 7999: Fеrguson еt al. 200З). Thе impliсations for human hеalth arе еnormous, Ьoth in tеrms of prеdiсting how long vaссinеswill rеmain еffесtivе (D. J. Smith 2006) and in thе possiЬility of mutations or antigеn shuffling ЬеtwееI-lvirus suЬtypеs,whiсh сould lеad to сhangеs in virulеnсе and transmission Ьеtwееn hosts (Baigеnt and Мс. Саuley 200З; Kuikеn еt аl. 2006\. Тhе grеаt fеar, r>fсollrsе' is that thе H5 hеmagglutinin will сhangе influеnza's tгаnsmissiЬility in humans, for instanсе)Ьy еvolving HA affinity frorn сеlls dееp in thе lungs tо сеlls that linе our throats and nosеs. Rathеr than sсаttеrеdсasеs assoсiatеdwith ехposurе to infесtеdwatеrfowl or poultry, a nеw form of HSN1 сould Ье transmittеd Ьy dirесt сontасt Ьеtwееn pеoplе, lеading to disеasе outЬrеaks in human populations. GЕNЕтlсs oF MUтAтloN Many wеll-known human disеasеs rеsult from mutarions in our gеnomеs. Мutation is also inеvitaЬlе, a сonsеquеnсе of mistakеs in сopying thе DNA that for thе most part kееps thе rесoгd straight during сеll сyсlеs that rеnеw our Ьodiеs and makе our еggs and spегrrr.Soпtе mutations :rгеspontanеous' somеarе еnvironmеt-ttally сaused,Ьut геst ;rssurеdthat mutation nеvеr slеeps. Individualmlltаtions оссur at rеlаtivеly low гatеs,Ьut thе numbеrs arе tiltеd in favor of mutаtions appеaring in high absolutе frеqr.rеnсy.Prеvalеnсе of сommon gеnеtiсdisеasеslikе diaЬеtеs,musсular dystrophiеs'and сanсегsсan

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Еuolutioпаrу Biologу of Disеаsе апd Dаrtaiпiап Меdiсiпе Ье undеrstood in thе framеwork of еvolution viа thosе inехoraЬlе mutations and thеir inhеritanсеwithin familiеs and еthniс groups (Frank 2004; Tishkoff and Kidd 2004). At thе Ьasе lеvеl mutаtions аrisе in somewhеrе Ьеtwееn 1 in 10'000 and 1 in 100,000,000 DNA rеpliсations.Givеn а human population of morе than 6 Ьillion pеrsons' еaсh with 30,000 gеnеs and 6 Ьillion Ьаsе pairs of DNA' novеl mutations will arisе еaсh gеnеration Ьy thе thousands,if not millions. SuЬsеquеntly,novеl mutation саn Ье traсеd and prеdiсtеd within familiеs Ьy pеdigrееs Ьut сan also сomе to diffеr in frеquеnсy bеtwееn pсlpulations with highеr or lowеr proЬaЬility of inhеritеd disеasе. Thе vаst majority of mutations will disrupt gеnеs and Ье harmful. Сonsidеr phеnylkеtonuriа (PKU), thе gеnеtiс disеаsе сausеd Ьy thе inaЬility to mеtaЬolizе thе amino aсid phеnylalaninе Ьесausе of mutations in thе PАH gеnе (Sсrivеr and !Иatеrs 7999). Thе disеasе has variaЬlе phеnotypеs' of whiсh mеntal rеtаrdation is onе of thе wоrst, Ьut it сan Ье avoidеd if phеnylalaninе is еxсludеd from thе diеt of affесtеd individuals (сarеfully rеad thе laЬеls of your low-сaloriе soft drinks). Morе than 400 mutant PАH allеlеs that еnсodе malfunсtioning еnzymеs havе Ьееn idеntifiеd in various human populations. Routinе nеonatal sсrееning for unusually high phеnylalaninе lеvеls and dеfесtivеPAH еnzymе now providеs a rapid tеst for diagnosisand trеatmеnt Ьеforе thе most sеvеrеsymptoms dеvеlop. On thе othеr hand, somе positivе surprisеs arе hiddеn in thе human gеnomе as wеll. A numЬеr of individuals of northеrn Еurсlpеan dеsсеntinfесtеd with HIV-1 havе nеvеr dеvеlopеd AIDS, and many of thеm arе homozygous (havе thе samе allеlе on Ьoth сhromosomеs)for a mutation in thе сytokinе rесеptor ССR5 on thе surfасе of СD4+T сеlls of thе immuпе systеm (Dеan et a|. 1996). HIV.1 usеs thе ссR5 rесеptor to еntеr СD4+T сеlls and еvеntuаlly ovеrwhеlms thе population of hеlpеr T сеlls that nоrmally rеspond to invadеrs in thе body, lеading to a сollapsе of thе immunе systеm and AIDS. This mutation is сallеd СсR5-^З2 Ьeсausе of a dеlеtion of 32 Ьasе pairs in thе gеnе, lеading to a nonfunсtional protеin that prеvеnts HIV-1 from Ьinding and invading СD4+T сеlls. ССR5-AЗ2 is found in 5% to 15Y" of northеrn Еuropеans Ьut is еssеntially aЬsеnt from Еast Asian' Afriсan, and Nativе Amеriсan populations (Dеаn еt aL.2,002). Bесausе it is impossiЬlе that AIDS sеlесtеd for inсrеasеd frеquеnсy of ссR5-^32 within a singlе gеnеration' it has Ьееn suggеstеdthat high frе. quеnсy of ССR5-A32 rеsultеd from strсlng sеlесtion in thе past, еspесially from infесtion Ьy plaguе or smallpox, whiсh wеrе Ьoth сommon and dеаdly in Еuropеan pоpulations during mеdiеval timеs and until thе latе 1700s (Galvani and Slatkin 200з). As is oftеn thе сasе with surmising sеlесtionin thе past' othеr еvidеnсеdoеs not nеatly fit thе plaguе or smallpox hypothеsеs.In miсе infесtion Ьy thе plaguе Ьaсtеrium is as ссlmmon in ССR5-dеfiсiеnt s t r a i n sa s i n С С R 5 * s t r a i n s ( M е с s a sе t a l . 2 0 0 4 ; Е l v i n е t a l . 2 0 0 4 ) ' i n h u m a n populations sеvеralothеr nonfunсtional allеlеsof thе ССR5 rесеptor also ехist in high frеquеnсy (Blаnpain еt al. 2000), and thе ссR5-^32 mutant аllеlе has Ьееn rесovеrеdfrom Bronzе Agе (2,900 yеars ago) skеlеtonsfrom sеvеral plасеs in Еuropе long Ьеforе plaguе is thought to havе invadеd (Hummеl еt

al. 2005). Rеgardlеs sist, and it appеars t nеtiс drift, providеs l allеlеs (Blanpain еt 2005; Sabеti еt al. 2( Finally, infесtions tiеnts' and Darwinia on human hеalth. Рс of thеir gеnеtiсs an( prеdisposеd to infесt onсе infесtion sеts il For instanсе' somе a сеptibility to a whol rosy, tuЬеrсulosis, m 2002). Еvеn morе p likе dеnguе' influеnz damagе from thе pa tеm whilе attaсking 1 disеasе arе сomplеx and immunе rеspons

Diagnosis

Whаt aspесts of сarе winian approaсh to с Ьeyond individual pа thеir сonnесtions wit lutionary history. Th mеnt to allеviatе pai rapid diagnosis, trеa mеnt of fеvеr and iro thеsе may rеprеsеnt growth of Ьaсtеria (l Trеating thе symptor that infесtions pеrsist Thе follоwing dесi and hopеfully сan lеa thе Ьasiс symptoms z standing of disеasе:

1. Is this an infесti 2' If it is an infесtiс a. If othеrwisе ul еnvironmеnt ( hazards)?

ш Меdiciпе n via thosе inеxoгаЬlе mutations (Frank 2004; Tishkoff niс gror'rps arisеin somеwlrеrеbеtwееn 1 in ior-rs. Givеn a humаn populаtion з0,000 gеnеs and 6 billion Ьаsе h gеrrеrationЬy thе thousands, if an Ье trасеd and prеdiсted within iffеr in frес1uеr-rсY Ьеtwееn popu_ rhеritеddisеаsе. Цpt gеnеsand Ье hагmful. Сonisеаsесausеd Ьy thе inaЬility to ес21usе of mutarions in thе PАH asе hаs variaЬlе phеnotypеs, of t, Ьut it саn Ье аr,oidеdif phеny:d individuals (сaгеfully rеаd thе rе than 400 rnr.rtаntPАH аllеlеs lееn idеntifiеdin various human lr unusually high phеnylalaninе cеs a rаpid tеst for diagnosis and dеvеlop. 'risеs аrе hiddеn in thе huntаn f n < l r t h е rЕ n u г o p е а nd е s с е n t i n IDS, аnd many of thеm arе hoomosоmеs)fсlr a trrutationin thе ]D4+T сеlls of thе immurrе sys_ '5 rесеptorto еntеr СD4+T сеlls lf hеlpеrT сеlls that normally rеr ссlllapsеof thе ir-nmunеsystеll1 \32 Ьесausеof а dеlеtion of З2 ullсtional protеin that prеvеnts сеlls. ССR5-A32 is found in 5"% :ntially aЬsеnt from Еаst Asiаt-t, Dеаnеt аl. 2002)' сtеd for inсrеаsеd frеquеnсv of as Ьееn suggеstеdthat high frеsеlесtionin thе past, еspесially n wеrе Ьoth сomr-rronand dеaс1lу nеs and until thе latе 1700s (Gаl_ э rvith surmising sеlесtion in thе laguеor smallpoх hypothеsеs.In as сommon in CСR5-dеfiсiеnt ) 0 4 ;Е l v i n е t a l . 2 0 0 4 ) , i n h L r m a n lеs of thе ССR5 rесеptor also еxаnd thе ссR5-^32 mutant allеlе yеaгsаgo) skеlеtonsfrom sеvегаl ght to havе invаdеd (Hummеl еt

Еuolutioltаrу Biologу of Disеаsе апd Dаrtuiпiап Меdiсine al. 2005). Rеgardlеss,sеvеralothеr mutаtions in thе ссR5 rесеptor also pеrsist,and it appеars that sеlесtionvia rеsistanсеto infесtions, rathеr thаn gеnеtiсdrift' providеs а plausiЬlе еxPlanation for thе high frеquеnсy of mutant allеlеs(Blanpain еt al. 2000; Galvani and Slatkin 2003; Novеmbrе еt al. 2 0 0 5 ;S a Ь е t iе t a l ' 2 0 0 5 ) . Finally, infесtions and gеnеtiс disеasеsoftеn сo-oссur within thе samе patiеnts,and Darwinian mеdiсinе сan also еnсompass this Ьroаdеr pеrspесtivе on human hеalth. Patiеnts may Ье siсkеnеd Ьy pathogеns, Ьut othеr aspесts of thеir gеnеtiсs and еvolutionary history (еthniсity) сan makе individuals prеdisposеdto infесtion or to grеatеr pathсlgеnеsisand morе sеvеrе disеasе onсе infесtion sеts in (Сookе and Hill 2001; \Wеissand MсN4iсhael 2004). For instanсе,sоnrе аllеlеs oi HLA gеnеs of thе immunе systеm inсrеasе sus. сеptiЬilityto a wholе variеty of pathogеns, inсluding thosе that сausе lеprosy, tubеrсulosis,malaria' and AIDS (Hill and Motulsky 7999; Dеan еt al. 2002)' Еvеn morе profound is that disеаsе fгom сommon human maladiеs likе dеnguе'influеnzа,malaria, and tuЬеrсttlosisгеsr'rltsnot only from diгесt danagе from thе pаthogеns bцt also froпr ovеrrеасtion of thе immunе sys. tеm whilе attaсking thosе pathogеns (Graham еt al. 2005). Thus thе roots of disеasеarе сomplех and in many instanсеs grow from dееp in our gеnеtiсs аnd iпrmunе rеsponsеsto infесtions,аppropгiatе or not.

Diagnоsis What aspесtsof сarе for thе siсk and for publiс hеalth distinguish thе Dar. winian approaсh to disеasе?Thе largеst distinсtion is ехtеnding mеdiсal сarе Ьеyondindividual patiеnts to сonsidеr human populations in thе сonteхt of thеir сonnесtionswith thе miсroЬial world аnd thе patiеnts' gеnеtiс and еvolutionary history. This сan bе donе without сompronrising immеdiаtе trеatmеnt to allеviatе pain and sLrffеringand in many сasеs сan providе morе rapid diagnosis, tгеatmеnt' and rесovеry. A typiсal ехanrplе aгisеs ln trеat. mеnt of fеvеr and iron dеfiсiеnсvin patiеnts rvith infесtions,ЬесausеЬoth of thеsе may rеprеsеnt part of an adaptivе dеfеnsivе rеsponsе to slow thе growth of baсtеriа (Williams and Nееsе 1991; Nееse and.!7illiams 7994). Trеating thе symptoms of infесtеd patiеnts сould havе thе undеsiгеd еffесt that infесtions pеrsist longеr, with grеatеr potеntial for tгansmission. Thе following dесision trее slrows рatЬwаys through this Ьroadеr сontехt and hopеfully сan lеad physiсians not only to diagnosе and trеat disеаsеonсе thе Ьasiс symptoms and сausеs arе known Ьut also toward а gloЬal undеrstandingof disеasе: 1. Is this an infесtion or a соrrgеnitаlсondition? 2. If it is an infесtion, is this pеrson othеrwisе hеаlthy? a. If othеrwisе unhеalthy, is thе patiеnt сompromisеd Ьy poor еnvironmеnt (е.g.'pooг diеt and nutrition, smoking, or oссupational h a z a r d s )?

287

288 Еuolиtioпаrу Biologу of Diseаsе апd Dаrtuiniап Меdiсiпе Ь. If othеrwisе unhеalthy Ьut with a good еnvironmеnt,сould thе patiеnt bе gеnеtiсаllyprеdisposеdto infесtion (е.g.,poor immunе systеm)? If с. othеrwisе hеalthy, should symptoms Ье trеatеd (е.g.,nausеa,fеvеr, nasal сongеstion)'or should this infесtion Ье allowеd to run its сoursе with minimal intеrvеntion? 3. If it is an infесtion' is this pathogеn uniquе andlor сommon in humans, or is thе pathogеn's sourсе from othеr animals (сallеd zooпotiс diseаsе; .$Иolfe sее thе rеviеw Ьy et a|. 2О07|. .\iИhеrе a. did this patiеnt сontасt thе infесtious sourсе' and how was thе pathogеn transmittеd (..g., Ьy dirесt сontaсt or Ьy an arthropod vесtor likе a mosquito, flеa, or tiсk)? b. How сontagious is thе pathogеn:should patiеnts Ье isolatеd until thеy arе nо longеr infесtious? с. Do wе know thе infесtious miсroЬе's сlosеst rеlativеs?lй/ill thеraoiеs to fight thosе infесtions hеlp this patiеnt as wеll? d. Aftеr wе idеntify whеthеr thе pathogеn is a Ьaсtеrium, a virus, a protozoan' or a fungus, doеs thе infесtious agеnt havе rеsistanсеto antimiсroЬials? 4. If this is a сongеnital disordеr' what is this pеrson'sfamily history and еthniсity? a. Is thе individual from a small population with a history of marriagеs bеtwееn сlosе rеlativеs (е.g.,first сousins or сlosеr)? Ь. Is this disеasеhighly prеvalеnt in othеr pоpulations with thе samе еthniс origins? 5. !иill a thеrapy or intеrvеntion havе an еffесt Ьеyond this patiеnt? .!7ill a. thеrapy sеlесt for highеr pathogеniсity or virulеnсе in thе miсroЬеs (е.g.,еffесtsof impеrfесt vaссinеs)? .lfhat Ь. kind of sеleсtion prеssurе will antimiсroЬials сrеatе, and what will Ье thе tradе-off Ьеtwееn intеrvеning with a drug now and failurе of thеrapiеsin thе futurе if drug rеsistanсееvolvеs? Еffесtivе usе of this dесision treе prеsupposеs a tесhnologiсal world whеrе laЬoratory diagnostiсs Ьasеd on modеrn Ьioсhеmistry and gеnomiсs are availaЬlе for rapid sсrееning.lThis trее also prеsumеs that mеdiсal and hеalth profеssionals lеarn thе naturаl history аnd есology сlf pathogеnsand parasitеs in thе arеa whеrе thеy praсtiсе, and that thеy undеrstand thе еthniс divеrsity of thе population thеy sеrvе. Thе work of Dr. D. Holmеs Morton аmong thе Amish of Pеnnsylvania and Illinois providеs а сlеar сonnесtion Ьеtwееn Ьiomеdiсal rеsеarсh and сliniсal praсtiсе (Bеlkin 2005). Мorton and сollеaguеs first diagnosеd and thеn idеntifiеd thе undеrlying сausеs of prеtzеl syndromе, a form of сеrеЬral palsy with Sеvеrеmеntal rеtardаtion and thеn еarly dеath in аffесtеd сhildrеn (Straussеt al. 2003). Similar tо PKU, prеtzеl syndromе is glutariс aсiduriа (GA1)' сausеd Ьy m'-rtationsin thе dеgradation pathwаys of thrее amrno

aсids (lysinе, hydro triсian, Ьut in his сl first dеtесt GA1 via a gеnеtiс tеst Ьasеd whеrе thе Amish or of Еuropеan dеsсеn rеduсеd among Am Rесognizing this сinе. In part this kir sionals undеr thе st thе silvеr_Ьullеtyеa in thе 1930s and 1j rеdisсovеry of this t thеrapiеs and thе rс losis that wеrе thol Andеrson 1999)'

Trеatmеnt and.

Darwinian mеdiсint thе patiеnt in front prеdiсtivе and prееr thе mеdiсal world, еmbraсе Ьoth natur thе proсеss that trа translation humans nесtions to thе natu sсiеnсе of еvolution dеvеloping trеatmеr Ье sееn latеr, somе . thе сost оf ignoring сasеs. ADAPтAт|oN

If onе сonsidеrs miс сausе rеsistanсе to i rееmеrgеnсе of prе. Andеrson 19991 L< multiplе-drug rеsist Ьy aсquiring drug rс This is truе for Nels gonorrhеa and dirес Similarly' multidгug

Еuolutionаrу Biologу oi Diseаsе аnd Dапuiniап Меdiсine

ап Меdiсiпе od еnvironmеnt,сould rhе infесtion(е.g.,poor immunе ns bе trеatеd(е.g.'nausеa, fеvеr' сtiоn Ье allowеd гo гttn iгs iquе and/orсommon in humans, animals(саllеdzooпotiс diseаse; fесtioussourсе' аnd how wаs rесtсontaсt оr Ьy an arthropod luld patiеntsЬе isolatеd until ; сlosеstrеlativеs?Will thеrapies iеnt as wеll? 3еnis a baсtеrium,a virus, a )сtiousagеnthavе rеsistanсеto this pеrsorr'sfamily history and r t i o nw i t h a h i s r o г yo f m а г г i а g е s t s i n so r с l o s e г ) ? rеr popr-rlatiоnswitlr thе sап-tе еffесt Ьеyоnd this patiеnt? ;еniсityor virulеnсе in thе rссinеs)? antimiсroЬiаlsсгеatе,and what ning with a drug now and .ugrеsistanсееvolvеs? osеsa tесhnologiсalworld whеrе Ь i o с h е n r i s t r уa n d g е n o l n i с s a г е rlso prеsurnеsthat mеdiсаl and :y and есology of pathogеns and d that thеy undеrstandthе еthniс long thе Amish of Pеnnsylvаnia ]twееn Ьiomеdiсal rеsеarсh and d сollеaguеsfirst diagnosed and zеl syndromе, a form of сеrеЬral n еarly dеath in аffесtеd сhildrеn lеl syndromе is glutariс aсiduria l a t i o n p a r h w а y so f t h r е е a m i n o

асids (lysirrе,hydгoхylysinе, and tryptophan). Morton is primarily a pеdiatriсian,but in his сliniс in сеntral Pеnnsylvarriahе pursuеd thе tесhnology to firstdеtесtGA1 via nondеgrаded protеins in цrinе samplеs and thеn dеvеlop a gеnеtiсtеst Ьаsеd on miсroсhips. Thе mutation has Ьееn traсеd to Еuropе, whеrеthе Amish originatеd, and oссurs at low frеquеnсy within populations of Еuropеarrdеsсеnt. \With sсrееning and diеt, disеasе prеvalеnсе has Ьeеn rеduсеdamong Amish to a third of thе prеtrеatmеnt ratе. Rесognizing this Ьroаdеr сontехt is an intеgral part of Darwinian mеdiсinе' In part this kind of training was at onе timе providеd to hеalth profеssionalsundеr thе suЬjесt of gеographiс mеdiсinе, Ьut it was swеpt asidе in thе silvеr-Ьullеtyеars immеdiаtеly aftеr thе disсovеry of antimiсroЬial drugs i n t h е 1 9 3 0 s a n d 1 9 4 0 s ( B u r n е ta n d W h i t е | 9 7 2 ; W . A n d е г s o n 2 О О 4 ) . Т h e rеdisсovеryof this Ьranсh of mеdiсinе сomеs on thе hееls of failurеs of drug thеrаpiеsand thе rееmеrgеnсеof infесtious diseasеslikе polio and tuЬеrсulosis tlrаt wеrе thought to havе Ьееn сonquеrеd (Gаrrеtt 19941 Lеvin and Andеrson 1'999).

Trеatmеntand Thеrapy Dагwinian mеdiсinе asks hеаlth profеssiorrаlsto look Ьеyond symptoms of thе patiеnt in front of thеm and to praсtiсе mеdiсinе in a way that is Ьoth prеdiсtivеand pгееmptivе(Zеrhouni 2005; Сulliton 2006)' Thе сhallеngе to thе mеdiсal world, inсluding Ьiomеdiсal rеsеаrсh and drug disсovеry' is to еmЬrасеЬotlr rratural sеlесtiorrand сommon dеsсеnt (horn
289

2 9 0 Еuolutionаrу Biolсlgу of Disеаsе аnd Dаrtuiпiап Мediсiпе аurеus' whiсh is oftеn aсquirеd in hospitals. In its nеw and impеrvious form this сommon skin Ьaсtеrium сausеs sеvеrе disеasе of skin and soft tissuеs' somеtimеslеading to dеath (Diеkеma еt al. 2001; Еady and Сovе 2003). on thе othеr hand, it is implausiЬlе that humans will еvolvе nеw mесhanisms of disеаsеrеsistanсе,at lеast in thе aЬsеnсеof somе kind of rеgular and сatastrophiс сhallеngе that would sеvеrеly rеduсе fitnеss of thosе who laсk gеnеtiс prеdisposition for fighting infесtions. Again' this is not to say that humans havе always Ьееn unaffесtеd Ьy thе powеr of natural sеlесtionrесеnt gеnomiс analysеsshow ongoing sеlесtionin Ьrain sizе (Mеkеl-BoЬrov еt al. 2005) and rесеnt sеlесtion for adцlt laсtosе mеtaЬolism in Еuropеan and Afriсan populations (Tishkoff et a|. 20О7). But thе disparity of gеnеration timеs of miсroЬеs аnd hцmans spurs natural sеlесtion in favor of mi сroЬеs, whiсh will еxpеriеnсе sеlесtion at multiplе lеvеls: within individual hosts, Ьеtwееn human hosts, and Ьеtwееn humans and pathogеn rеsеrvolrs in сommеnsal or wild populations of othеr animals. An intriguing possiЬility is that our immunе systеms arе сurrеntly undеf sеlесtion via immunopathology, disеasе саusеd Ьy ovеrrеsponsеЬy our im. munе systеms to What сould othеrwisе Ье mild infесtions (Graham еt al. 2005). our immunе systеms сould Ье sееn as a sеriеs of tradе-offs Ьеtwееn rесognition of sеlf and nonsеlf, dеfеnsе against invading pathogеns, and thе potеntial damagе to noninfесtеd tissuеs whеn сlеaring invadеrs from infесtеd tissuеs. In this сasе sеlесtion would Ье toward an intеrmеdiatе phеnotypе that Ьalanсеs tradе-offs. Gеnomiс analysеs of immunе-systеm gеnеs' сomЬinеd with ехpеrimеnts in modеl systеms that furthеr dеmonstratе how thеsе kinds of tradе-offs funсtion, will providе an aсtivе arеa of rеsеarсh for yеars to сomе (Graham еt al. 2005). Thus modеrn mеdiсinе still finds itsеlf on a shifting landsсapе, and wе сontinuе to writе thе сhaptеr in human history suggеstеd Ьy Joshua LеdеrЬеrg (2000)' whiсh hе сalls ..our !Иits vеrsusThеir Gеnеs.''Еvolution in miсroЬеs will nеvеr stop, Ьut wе arе Ьеginning to apply stratеgiеs spесifiсally dеsignеd to halt thеir transmission, slow rеsistanсе to antimiсroЬials, and improvе vaссinеs. Thе first issuе is pеrhaps thе simplеst: hygiеnе сan halt pathogеn transmission. This was immеdiatеly apparеnt from thе famous еpidеmiologiсal slеuthing by Dr. John Snow in London, who in 1854 rеmovеd thе handlе of a puЬliс watеr pump on Broad Strеet in Soho and provеd that a loсal сholеra еpidеmiс сamе from a сontaminatеd wаtеr supply (!7ills 1996). Sim. ilarly, plaguе and thе Blaсk Dеath' сartsеd Ьy thе baсtеrium Yеsiпiа pеstis and rеsponsiЬlе for somе of thе most infamous human pandеmiсs, havе largеly wanеd as human disеasеsin arеas whеrе rodеnts and thеir flеas arе rеmovеd from human living quartеrs (Gagе and Kosoy 2005). In tеrms of еvo. lutionary Ьiology, hygiеnе сirсumvеnts thе opportunity for sеlесtion for pathogеns by simply rеmoving сhains of infесtion and prеvеnting transmission (Galvani2003). Slowing еvolution of antimiсroЬial rеsistanсе is onе of thе largеst publiс hеalth сhallеngеs wе faсе, Ьut most work in this arеa is hypothеtiсal Ьесausе сritiсal data that сould distinguish whiсh stratеgiеs would Ье most еffесtivе

arе not yеt availal simulation studiеs glе drug until rеsi grеatеst hеalth Ьеr thе samе pаtiеnts with thе lowеst trа son 1.999;'Bull an< Again, possiЬlе ou сontrollеd human providе dеfinitivе l As notеd for inf сult, although sеvс u s е ( е . g . ,m е a s l е s possiЬility that Н5 human pathogеn' : for widеsprеad usi сinе will providе s fortunаtеly' this sеlесtion within ht high гаtеs of path сally' impеrfесt vа mission to еsсapе ] individuals (Gand hеalth impliсationl must takе into aсс and thаt within-l (Stеarns and ЕЬеrt loсal outЬrеaks сor pathogеns in thе ft Finally, muсh ht mеnt that pathogе slows. transmissio virulеnсе idеа сom. Еuropеan raЬЬits i the virus was intro sсapе. Lowеrеd vir is а sесond ехampl sis that Ьalanсеs vi nition of virulеnсс within thе host, to> host, and, finally, Neisseriа meпiпgitt transmission is fror ally asymptomatiс. mission and is aсtu optimal virulеnсе с

ап Меdiсiпe . In its rrеwand impеrvious form disеаsеof skin and soft tissuеs, 2О0I;Еadyand Сovе 200з). humans will еvolvе nеw mесhasеnсеof somе kind of rеgulaг and rеduсе fitnеss of thosе who laсk rs. Again, this is not to say that hе powеr of natural sеlесtion:tionin Ьrain sizе (Меkеl-BoЬrov laсtosеmеtaЬolism in Еuropеan t07).But thе disparity of gеnеranatural sеlесtion in favor of mi. multiplе lеvеls:within individual h u m а n sа n d p a r h o g е nr е s е г v o i r s animals. lunе systеms arе сurrеntly цndеr " r s е dЬ y o v е r r е s p o n s еЬ y o u r i m : mild infесtions (Graham еt al. as a sеriеsof tradе-offs Ьetwееn inst invading pathogеns,and thе :n сlеaring invadеrs from irrfесtеd паrd an intеrmеdiаtе phеnotypе ; of immunе.systеmgеnеs' сomat furthеr dеmonstratе how thеsе l aсtivе arеa of rеsеаrсh for yеars a shifting landsсаpе' and wе сony suggеstеdЬy Joshua LеdеrЬеrg еir Gеnеs.''Еvolution in miсrobеs lly stratеgiеsspесifiсallydеsignеd to antimiсroЬials, and improvе plеst: hygiеnе сan halt pаthogеn nt from thе famous еpidеmiologiwho in 1854 rеmovеd thе handlе Ln Soho and provеd thаt a loсal l watеr supply (Wills 1996). Simr Ьy thе Ьасtеrium Yеsiniа pеstis [amous human pandеmiсs, havе rеrе rodеnts and thеir flеаs arе rеnd Kosoy 2005). In tеrпrs of еvo. rе opportunity for sеlесtion for . f е с t i o na n d p r е v е n t i n gt r a n s m i s :anсеis onе of thе largеst puЬliс Lthis arеa is hypothеtiсal Ьесausе tratеgiеswould Ье most еffесtivе

F,uolutionаrуBiolrlgу of Diseаsе аnd Dаrtuiпiап Мediсinе arе not yеt avirilaЬlе (Lipsitсlr 200l). Rеgardiеss,mathеmatiсаl modеls and simulation studiеs indiсatе th;rt in liеu of attirсking еaсh miсгoЬе with a singlе drug until геsistanсеrеaсhеs a lеvеl that сompromisеs puЬliс hеalth, thе grеatеsthеalth Ьеnеfitswill Ье gainеd by dеploying сomЬinаtions of drugs in thе samе pаtiеnts at tЬе sаmе timе or targеting for сontrol thosе pathogеns rzrtеs(BonhoеftЪrеt a|. |997: Lеvin and Andеr_ rvith thе lowеst transmissiс.lt-t B u l l soo1,999 а n d W i с h m a r r2 0 0 1 ; L i p s i t с h 2 0 0 1 ; D . L . S m i t h е t a l . 2 0 0 5 ) . Аgаin, possiЬ1еOutсomеslravееnоugh сontingеnсiеsthat orrly timе, сarеfully сontrollеdhumarrtrials, and laЬoratory ехpегimеntswith modеl systеmswi1l pгovidedеfinitivе 11llswеrs. As notеd for influеnza A' kееping еffесtivе vассinеs orr hand сan Ье diffi_ сult' although sеvеral vaссinеs havе rеmainеd еffесtivееvеn aftеr dесadеs of usе (е.g.,mеaslс.svассinеs). T.his quеstion has arisеn again bесausе of thе possiЬilitythаt H5N1 avian influеnza сould еmеrgе as a dirесtly transmittеd huпrаnpаthogеtr,irпd it is not fе:rsiЬlеto providе pеrfесtly matсЬеd vaссinеs for widеsprе:rdusе. Thus thе hopе is thаt еvеn an impеrfесtly matсhеd vaссinе will providе somе lеvеl of protесtion аnd slow virаl transmission. Unfortunatеly, this doеs not takе into aссount that pathogеns undеrgo sеlесtionwithin lrosts that сtluld favor morе virulеnt pаthogеns (dеfined Ьy high ratеs of pathogеn rеpliсаtion сalising сеll оr tissuе damagе). Spесifiсally' impеrfесr vaссinеs mav сalrsе pathogеns to еvolvе Ьoth fastеr transrnissionto еsсаpе protесtеd irrdividuals and highег virulеnсе in unprotесtеd i n d i v i d u a l s ( G а r - r d o nе t a l . 2 0 0 1 ; v a n B o v е n е t a l . 2 0 0 5 ) . A g a i n , p u Ь l i с hеalth impliсаtiotls of using virссinеsthat only Partially pгoteсt individuals must takе int() ассount that sеlесtion or-rperthogеnsoссLlrs at sеvеral lеvеls, and that wirlrin-host еvolution gеnеrаlly Sеlесts for grеatеr virulеnсе (Stеarnsand ЕЬеrt 2001; Galvani 2003). Rеlеasing partial vассinеs to stеm loсal outЬгеaksссluld havе thе unintеndеd risk of sеlесtingfor morе virulеnt pаthogеnsin thе futurе. Finally, nrшсlrhas Ьееn nrаdе оf thе еvolutiсln of virulеnсе and thе argumеnt that pathogеns should еvolvе lowеr virulеnсе Ьесausеdamagе to lrosts slows transmission (Еwald 1994). Еmpiriсal support for thе optinralvirulеnсеidеa сoп-tеsfrom a fеrv еxamplеs likе thе rеduсеd dеath ratе among }-uгopеanrаЬЬits ilrfесtеdwith nryхoma virus in Austгаliа in tlrе yеars aftеr thе virus was introduсеd tс.lсontrol thе r:rЬЬitsthat wеrе rаvaging thе landsсapе.Lowеrеd virulеnсе in thе Ьасtеrium that сausеs diphthеria in humans is a sесond ехanrplе (Еbеrt and Bull 200З). I}utagain, thе tradе-off hypothеsis that Ьalаnсеsvirulеnсе and trаnsmission assumеsa rеlativеly simplе dеfirrition of virшlеnсе, wlriсlr is асtually a fuIrсtion of pathogеn rеpliсation within thе host' tохiсity of rhе pathogеn to thе host' immunе rеsponsеof thе host, and, finally, whiсh tissuеs arе affесtеd. For instarrсе' thе Ьaсtеrium |'lеisseriаmeniпgitidis сausеs mеningitis whеn it infесts spirrаl tissuеs, Ьut its transmissionis from infесtions of thе uppеr геsPiratory trасt, whiсh arе usually asympt
291

2 9 2 Еuolutionаrу Biologу of Disеаsе апd Dаrшiniап Меdiсiпе virulеnсе сould Ье сontrollеd. Thе quеstion thеn arisеs: whаt will Ье thе targеt for sеlесtion?ЕЬегt аnd Bull (2003) suggеsttlrat sеlесtion should targеt virulеnсе dirесtly Ьy attaсking pathogеll toxiсity; vaссinеs against diphthеria and pеrtussis havе Ьееn dеsignеd to do just that, with thе rеsult that surviving Strainsarе lеss pathogеniс. сot",lMoN DEsсЕNт Idеas of сolnmon dеsсеntand homology may havе grеatеr diffiсulty in Ьеing aссеptеdin mеdiсal praсtiсе for thе samе rеasonsthat thе notion of сommon dеsсеnt gеnеratеsсognitivе dissonanсе in thе gеnеral population. Thе сonсеpt of homology, that traits in diffеrеnt spесiеshavе сommorr еvolutionary origins' is сritiсal to dеvеlopmеnt of pharnraсеutiсals,whiсh arе first tеstеd on mammals likе miсе, rats, аnd dogs. Promising сandidatеs may thеn Ье tеstеd on primatеs Ьеforе сliniсal trials with humаn voluntееrs. Thus Ьio. mеdiсal rеsеarсh advanсеs Ьy undеrstanding that spесiеs phylogеnеtiсaily сlosеst to hrrnranshavе thе most similar gеnеtiсS'physiology, :rnd immunе systemsto hurnаns аnd thus provе to Ье rеliaЬlе пrodеls for rеsеarсhand dеvеlopmеnt of trеatmеnt and thеrapy. How badly сan things go if соmmon dеsсеrrtis disгеgardеd?onе poignant сasе is that of BaЬy Faе, an infant Ьorn with an undеrdеvеlоpеdhеаrt who rесеivеd thе hеart of a ЬaЬoon at Loma Linda Univеrsity Mеdiсal Сеntеr in 1984 (Bаilеy еt al. 1985). Thе ЬaЬoon donor wzrsonе of fivе that had bееn tеstеdfor irnmunologiсal sinlilarity on thе lrasisof thrее HLА gеnеs.Thе ЬaЬoon with lowеst rеaсtivity to thе infant's illmunе сеlls (lymphoсytеs)was сhosеn as donor. BaЬy Faе survivеd for 20 days aftеr surgеry with thе hеlp of thе immunosuppгеssivе drug сyсlosporinе Ьut еvеntually diеd from rеjесtion of thе transplantеd hеart and othеr organ failurе. Еthiсal аnd proсеdural quеstions asidе, a trouЬling part of thе story is that sеvегаlmistakеs dirесtly rеsultеd from a rеjесtion of еvolutionary thinking. Lеonard Bаilеy' thе lеad suгgеon for BaЬy Faе's opеration, admittеd to Ьеing a fundamеntalist Сhristian during a radio intеrviеw for thе Aus. tralian Broаdсasting Сorporation.2 Bailеy сhosе ЬaЬoons as donors Ьесаusе thеir hеarts wеrе availaЬlе аnd thе right sizе. Askеd why hеarts of сhimpanzееs' humans' сlosеst living primatе rеlativе,wеrе not сonsidеrеd,Bailе,v answеrеd, ..Thе sсiеntists that arе kееn on the еvolutionary сonсеpt' that wе aсtually dеvеlopеd sеrially from suЬhuman primatеs to humans, with mitoсhondrial DNA dating and that sort of thing, thе diffеrеnсеs havе to do with millions of yеars. That bсlgglеsmy mind sornеhow.I don't undеrstandit wеll' and I'm not surе thаt it mеans a grеat dеal in tеrms of tissuе homology.'' Infant transplants Ьy Bailеv.s group at Loпra Linda suЬsеquеntlyusеd only human donors. Thе prospесt of using othеr spесiеsfor transplantationсontinuеs to Ье quеstionеd Ьесausеfor most organs thе сross-spесiеsimmunity Ьarriеr is high, еvеn with immunosupprеssivеdrugs, and Ьесаtrsеof thе risk that novеl pathogеns сould Ье transfеrrеd to hr:nransfrom thе dorror animаls (Dеsсhamps еt al' 200.5)'

Prognosis

!7hеrе doеs Darwir grеatеstсhаllеngеis to сhanging еnviror thе largеst and rn< doomsday sсеlrаrio thе possiЬility woul that сould rеduсе di of еvolution hаs m: Givеn variation ir-r1 fitnеss arrd with inl tion is a сеrtairlty.I intuitivе outсomеs lеvеls. Thе possiЬil most imрortant сon iсiriе (\й/illiamsаrrd fесt vaссinеs сluring potеntially alarmin1 whilе thе vaссinе sе п1orеsеvеrе disеasе aсross multiplе lеvе transmissiolt, l.lnсirt Nееsе 1991; Еlvаld Thе prognosis for п-ranpopulations is mеan that Е]еnеtiсsс triсizrrrswith infoгnr likе PКU and GA1, с сould Ье donе with l batеd, еspесially for foг infесtions, and rl thzlt саusе gеnеtiс di Ьut аgain, tlris is a m Progrеss in gегrеthе patiеnts to сurе thеi trial in Philadеlphia provеd Ьiotесhnolog nеtiс disеasесhаngе largе populati
Еuolutionаrу Bkiogу of Disеаsе аnd Dаrtuiпiап Меdiсiпе

iап Меdiсiпe on thеn arisеs: what will Ье thе suggеstthаt sеlесtion should tar,n toxiсity; vaссinеs against diph_ do just that' with thе rеsult that

аy havе grеatеr diffiсulty in Ьеing )asonsthat thе notion of сommon гhе gеnеralpopulation. Thе сonэесiеshavе сommon еvolutionary naсеutiсals'whiсh arе first tеstеd .omisingсandidatеs may thеn Ье ith human voluntееrs.Thus Ьioing that spесiеs phylogеnеtiсally еnеtiсs' physiology, and immunе iaЬlе modеls for rеsеarсh and dе:еntis disrеgaгdеd?Onе poignant ith an undеrdеvеlopеdhеart who nda Univеrsity Меdiсal Сеntеr in tor Was onе of fivе that had Ьееn lasisof thrееHLА gеnеs.Thе Ьaimmunе сеlls (lymphoсytеs) was lays aftеr surgегy with thе hеlp of ' u t е v е n t u а | ld yiеd from rеjeсtion r failurе. Еthiсal and proсеdural y is that sеvеralmistakеs dirесtly inking. tby Faе,s opеration' admitted to a radio interviеw for thе Aus. :hоsеЬaboоns as donors Ьесausе ;izе. Askеd why hеarts of сhimltivе' Wеrеnot сonsidеrеd, Bailеy n thе еvolutionary сonсеpt' that ranprimatеsto humans, with mithing, thе diffеrеnсеs havе to do d somеhow.I don't undеrstand it lеal in tегmsof tissuе homology.'' na Linda suЬsеquеntlyusеd only г s p е с i е sf o r t r a n s p l a n t a t i o nс o n . r g a n st h е с r o s s - s p е с i еism m u n i t y vе drugs,and Ьесausеof thе risk l humans from thе donor animals

Prognosis .!7hеrе doеs Darwinian mеdiсinе takе us in thе futurе? Fiгst and forеmost, thе grеatеstсhallеngеis that miсroЬеshavе an almost unlimitеd сapасity to аdapt to сhаngingеnvironmеnts,and that humans in thе modеrn world arе onе of thе largеst and most сonsistеnt еnvironmеnts аvаilaЬlе to thеm. But аrе doomsdaysсеnariosof disеasеpandеmiсs neсеssary?Not rеally, Ьut to ignorе thе possiЬilitywould also Ье foolish' and many intеrvеntionsсan Ье adoptеd thatсould rеduсе disеasеsеvеrity(Purssеll2005). Thе issuе is thatthе proсеss of еvolution has many faсеs,with сhangе in thе futurе as thе only сеrtainty. Givеn variation in pathogеn populations, with somе traits сonfеrring highеr fitnеssand with inhеritanсеof trаit diffеrеnсеs,adaptation Ьy natural sеlесtion is a сеrtainty.Rеsponsеsto sеlесtion,howеvеr, somеtimеsh:lvе сoLlntеrintuitivе outсomеs Ьесausе sеlесtion асts in diffегеnt dirесtions at diffеrеnt lеvеls.Thе possiЬility that еvolution oссurs at multiplе sсalеs is among thе most important сontriЬutionsеvolutionary Ьiology has madе to mоdеrn mеdiсinе (williams and Nееsе 1991; Stеarnsand ЕЬеrt 2001). Dеploying impеrfесtvaссinеsduring puЬliс hеalth еmеrgеnсiеs,as disсussеdaЬovе, providеs a potеntiallyalarming еxamplе, whеrе еpidеmiсs сould Ье slowеd rеgionally whilе thе vaссinеsеlесtsfor highеr virulеnсеamong surviving pathogеns,with morе sеvеrеdisеasеin suЬsеquеntoutЬrеaks (Gаndon еt al. 2001). Tradе-offs aсrossmultiplе lеvеls lay at thе hеart of thе еvolution of pathogеn virulеnсе, transmission,and rеaсtions of our immunе systеmsto invadеrs (Williаm and N е е s е1 9 9 1 ;Е w a l d 1 9 9 4 ; Е Ь e r ta n d B u l l 2 0 0 З ; G г a h a m е t а l . 2 0 0 5 ) . Thе prognosis foг gеnеtiс сhangе that would rеduсе disеasе inсidеnсе in human populations is miхеd. Rapid advanсеs in gеnomiсs and gеnе disссlvеry mеan that gеnеtiс sсrеening,prеnatаlly or soon aftеr Ьirth, will providе pеdiatriсiаns with informatiсln nееdеd to trеat еvеn morе of thе mеtaЬoliс disеasеs, likе PKU and GA1, сausеdЬy mutations.Gеnеtiс sсrееningof adults,аnd whaг сould Ье donе with that information, is a lnattеr of еthiсs thаt is still Ьеing dеЬatеd,еspесiallyfor thе risk of gеnеtiсdisеasе,thе prеdispоsitionof irrdividuals for infесtions, and ratеs сhargеd for hеalth insuranсе. Sсrееning for nlutatit-'rls that сausе gеnеtiс disеasесould hеlp potеntial parеnts dесidе how ttl proсееd, Ьut аgain, this is a mattеr of privaсy and еthiсs сlutsidеthе sсiеnсеof еvolution. Progrеssin gеnе thеrapy-rеintroduсing funсtional gеnеs into thе gеnomеs of sеt baсk aftеr a fatality in a gеnе thеrapy patiеntsto сurе thеir disеasе triаl in Philadеlphia in 1999 (Thompson 2000) Ьut is Ьеing rеvisitеd with improvеd Ьiotесhnologiеs.But nothing in thе study of modеrn gеnomiсs and gе. nеtiс disеasесhangеs thе faсt of human population sizе' and that mutations in largе populations oссur аt high aЬsolutе ratеs. Thus Wе сan still prеdiсt with сеrtаintythаt еugеniсs,thе disсardеd ntltion that sеlесtivеЬrееding of humans сouldеradiсatеgеnеtiсdisеasе,would do еvеn lеssnow to allеviatеhuman mts. еry than it did a сеntury аgo whеn еugеniсsprograms wеrе first institшгеd.r Thе proЬlеms that faсе Darwinian mеdiсinе arе thе samе onеs that шakе еvolutionfasсinatins to somе and frustrating to othеrs. \й/ithinthе rnoге сеrtain

2L).]

294

Еuolutioпаr\, Biсllсll| сlf Disеаsе апd Dаrtuiпiап Меdiсiпе framеwork of inhеritarrсеand natural sеlесtion, еvolution is influеnсеd by сhanсе еvеnts likе mutаtions, сhanсе еnсountеrs with an individual who brings а nеw infесtion into а сommunitУ' or a rapidly altеrеd еnvironmеnt. On thе onе hand' somе find сomfort in thе idеa from Darwinian mеdiсinе ..prеdiсtеd'' that sonrе disеasеsсan Ье from tlrе maladaptatiс-ln сlf humаns to .Williаms thеir сurrеnt r,vоrld(Nееsе аnd 1994\. Orr thе othеr lrarrd,rvе rvould fееl ЬеttеraЬout Darwilrian mеdiсinе and looming plаguеsof mсldеrntimеsif thе idеntitiеsof thе nехt pandеmiс-сausingpathogеnsWеrе morе prеdiсtaЬlе (many would say that virusеs likе HSN1 or ЕЬola аrе most likеly; sее Сlеavеland еt a|.2007)..W.есan takе grеatеrсomfort, howеvеr,from gеographiсеpidеmiology, muсh as Darwin rnay havе found сomfort thгough his intеrеstin gеographiс distriЬutions of populations аnd spесiеs(Burnеt аnd Whitе 1972; LеdеrЬеrg 2000; W. Aгrdеrson 2004; Tishkoff and Kidd 2004). Thus wе know that thе historiеs of populations will influеnсе thе prеvalеnсе of сongеnital disordеrs, and wе know that disеasе organisms havе gеographiс origins, zrsdo thе resеrvoirs for disеasе and potеntial insесt vесtors for transmission. By :rсknowlеdgingtlrat humans livе :rspart of thе worldwidе есolоgy of infесtious disеasе аrndthat еvoiutioгrof pathogеns is thе inеvitaЬlе outсomе' wе саn Ье еvеn moге prеparеd thе nеxt timе thе monkеypoх visits Kansas.

AсKNoWLЕDGмЕNтs Mv rеsеаrсh is supportеd Ьv thе National Sсitr-rсеFоundation: Есolоgy оf Infесtious Disеаsеs Program (ЕF-0з27052) and thе Short Grаss Stеppе Long Tегm Есologiсal Rеsеarсh projесt (DЕB 02|7631). I thank thе еditors and anonymous rеviеwеrs,along with Irеnе Есkstrand, Normаn Johnson, Мary Pсlss,and my physiсian Мark Paulsеn, for сomnrеnts. I also thаnk Dr. Pаulsеn for his striсt attеntion tо mv iIrfесtionsarrd gеnеtlсs.

NoтЕs 1. А сavеаt must Ье mirdе hеrе:disеasеdеsсribеsthе physiсal damagе to а patiеnt' whiсh is аn individual phеnопrеnon.SсrееningсаIr idеntify individuаls with partiсular gеnotv1.tеs or spесifiс infесtions, Ьut thеsе individuals will nоt nесеssаrily dеvеlop disе.rsе.Nonеthеlеss' sсrееningсan pгеdiсt disеаsе'аnd disеirsеrisk сan Ье undеrstotldat thе lеvеl of pсlpulationswhеn ехposurеsto pаthogеnsаnd/Oг f r е q u r n с i е sо f g е r l е t i сm u t . r t i о n ьr r е h i g , h . 2. original rаdio Ьroаdсаst on Junе 3, 198.5,during thе progr:lm Hеаlth Report. 3. Sее Haldanе (1964I for an amusing аnd rеadaЬlееssay thаt dеfеnds mathеmatiсal thеoriеs of population gеnеtiсs,inсlr'rdingrеfеrеnсеto tl-rеЬаlanсе Iifg.е'..|i.o Ьеtwееn Inutаtion аnd sеlесtion,аnd somе lovеly r.еrsеaЬout his с11д,.n fight with сolorесtаl саnсеr.

в|BLIoGRAPlJY Andеrson, R. M., аnd R. М. Мay. |991. Iпfесtкlus Diseаsеsof Huш"tlts:Dупаmiсs апd Сопtrсll, oхfсlrd: Oхfоrd Univеrsitу Prеss.

Andеrson,\iи.2004' tWеntiеth-сеnt Btrigеnt,S. J., andJ. Ьirds:Dеtеrmin BioЕssауs25:6 Bаilеy,L. L., S. L. N

BаЬoon-tсl-hirm Amеriсаn Мedi Bеlkin, L. 2005. A d Blanpain, С., B. Lее. V. Wittаmеr, G nonfunсtional a 96: |6З8-1645 Bonhoеffеr, S., М. L to prеvеnt anтit Sсiепсes USА 9, Bull, J. J., and H. A. апd Sуstеmаtiс: Burnеt, N4., and D. t СamЬridgе: Са: Bush, R. М., С. A. I Prеdiсting thе е Сеntеrs for Disеasе outЬrеak of mt .Wisсonsin, 20( 642-646. С l е а v е l a n d ,s . , D . Т .!(lr еmеrgеnсе: Мiсrobiolo91,а Сoсlkе, G. S., and A disеasе.Nаture Сulliton, B. J. 2006 ZerЬouni. Неаt Dailv. G. С., S. Alеl H. A. N4oonеy 1997. Есosystе есosystеms.1ss Dеan, M., M. Сarri by gеnеtiс vеrsr Humаn Gепeti Dеаn, М., M. Cагri J. J. Goеdеrt' S Vlahov, R. Kas Gеnеtiс rеstriс1 allеlе of thе Сl Dеsсhamps, J. Y.' F хеnotransplan Diaпrond' J. 2003. Diеkеma' D. J.' }4. N4. Bеaсh, and to Stаphуlocoс susсеptiЬility с Еurоpе, and th Program, 199i

iап Меdiсiпе ] с t i o n 'е v o l u t i o n i s i n f l u е n с е d Ь y :ountеrswith an individual who э r а г a p i d l yа l t е r е dе n v i r o n m е n t . rе idеa from Darwirliilr-r mеdiсil-lе r thе rnaladaptatiorrof humans to 94). on thе othеr hаnd, wе would loming plaguеsof modеrn timеs if pathogеnsWеrе morе prеdiсtaЬlе ЕЬol:rаrе most likеly; sеe Сlеirvе)rt' howеvеr'from gеographiс еpi-rdсoпrfort through his intеrеst in i spесiеs(Burnеtand Whitе 1972; ,rkoff аnd Kidd 2004)' Thшs wе will influеnсе thе prеvalеnсе of Lsеasеorganisms havе gеographiс potrntiаl insесtvесtors for trans] as part of thе rvorldwidе есology . pathogеnsis thе inеvitaЬlе оutnехt rimе rhе monkеvptlx visits

: Foundаtion: Есologу of Infесtious rass StерlpеLong Tеrm Есologiсal toгs аtrd аnonyпlolls rеviеwеrs, alot.tg lss, аnd my physiсiirn Мark Pаulsеn, .iсt attеntiсlnto mу infесtions аnd

Ьеsthе physiсal damagе t() а patlеnt, аn idеntifr.individuаls u,ith pаrtiсrrlividLralswill not nесеssаrily Liсtdisеasе,and disе:rsеrisk саn Ье Osurеsto pаthogеnsand/or Juгing thе рIO!.rаm Llсаlth Rеpсlrt. LdаЬlееssaythat с]еfеnds ;luding rеfеrеnсеto thе Ьalanсе i vеrsеаbout his оwn lifе-еnding

lus Disaаsеsof Нumаtls: Dупаltliсs lss.

Еuolutionаrу

Biologу сlf Disеаse аnd Dаrшiniаn

Мediciпе

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thе ССR.5 ^32 L 1954-1962. olsеn, B., V. J. N4un R. A. М. Fсluсh Sсiепсa .] I2: 384 Puгssеll, Е. 200.5.Еvс Аduапсеd Nиrsil Ru:rn, Y. J., С. L. Wе P. Ng, K. P. Clhiu t,' F. P. Ng' R. Е Ссlmparаtivе ful isоlatеs and соm Lапсеt36I: |77 SlrЬеti'P. С., Е. Wrrls T. S. Nlikkеlsеn S. o,Briеn, and l Pиbliс Librа1' rl S с r i v е r 'С . R . , а n d P . frсrm рhеnvlkеtо

ап Мediсiпе

Еuolutioпаrу

us rеsistаnсе rеvisitеd:Сommunitys аurеus-aл еrrrеrging proЬlеm for :tions. Сltffе|1t Оpiпioп

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ites.Sсiепсе 282 14З2-143 5. tradе-offmodеl for thе еvolution Ь|e? Trands iп Мiсrobiolog1, |1: тith, G. Р. dе Lеma, S. Сhilla' P. Luсkow. 2004. AmЬiguous rolе of i : 10 . 10 3 8 / n а t rue 0 2 8 2 2 . zsсs. Nеrr. Yоrk: Oxford Univеrsity . 2003. Есologiсаl and эlution. N аtш,е 422: 428433' ..еr-inrightsfrom populаtion gеnеtory of plaguе: Pеrspесtivеs from uiешof Епtrlmolсlgу 50:505-528. onary есology. Trепds in Есologу plaguе and smallpoх as l.ristoriсal еsistanсеa||e|е.Proсeеdiпgs of tbе 276-15279. Rеad. 2001. ln-rpеrfесt vассinеs and 414:751-756. ': Pеnguin Bсloks. ' Whу ()ur'World No Longer Fits )rеss. ldrеls of San Маrсo and tlrе ]tationist рrogIammе. P roсeediпgs i:581-598. . Еvolutioпaгvсausеsand Reuiеtuоf Е,ссllogу,Еuolution, апd nian downsidеof past sltссеss? Vood,J. M. Daly, J. A. Mumford, triologiсаland еvolutionary t')

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Biologу of Disеаsе апd Dаrш'iпiаn Меdiciпe

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Bеyor Parad Biolo

Briаn G

Тhе quеstion that and funсtion in е stood. Form has t' gаnisms; and par individuаl organis сollесtivеs, suсh a! сharaсtеristiсs of l thеy havе аdaptil Howеvеr, thеrе is (i.е.,how thе forrл сеss whеrеЬy natt diffеrеnt forms in tion сannot ехpla plaining thе difft сontribution to th Thеrе is a tеndе сan Ье gеnеratеd indеfinitе divегsit assumption that I sis of two typеs (

spесiеs morpholo1 into distinсt, not ( сonstraints on tht somе forms саn Ь aminе in dеtail сс obsеrvational, ant а m p l е . A l l t h r е еa tion of сontinuou!

п Меdiсiпе Toпrasz. |999.TЬе dеvеlopmеnt :thiсillin-rеsist aлt Stаp hу loсoссus :diсiпе340:5\7-523' ; in influепza сorrtrtll. SсieпсеЗ12: 1005.Sггаtеgiс inrеritсгions in istanсe.Proсееdiпgsсlf thе З_з1.5 8. | .S a u n d е г2s 0. 0 5 'С o l l l p a r а г i v е :еsЬеtrvееlt thеpаtlrogеnrс 1 - 218 . Diseаsе.Nеw Yоrk: oхford :althаnddisеаsе: Work in progrеss. r' andD. H. Мortorr.2003.Typе I 7 pаtiеnts. AmеriсапJourпаlof

Bеyondthе Darwinian Paradigm:Undеrstanding Biologiсal Forms Briаn Goodtlliп

\ctаСhirurgiсаBеIgiса104: lеssons' highhopеs.FDА ;/fеaturеs/2000/5 00-gеnе.html. ls of Ьiogеography of l-ruman , Cenеtics36: S21_S27' ght'С. C. BаЬЬitt.J. S. Silvеrmаn' osпr:rn, М. IЬrahim,S. A. omar, еad,J. K' Pritсhard,G. A. !Иary, o no f h t r m a n l a с t a s pе е r s i s t е n сi n е

+0.

. Е . d е М е l k е r ,a n d М . Jеr irnpеrfесtvaссination: RоуаI Soсiеtу of Lolldoп, Series B d P . А . N 4 а t s o n 1. 9 8 6 . H u п t а r l эsis.ВiоSсiепcеЗ6: З68-373. D a s z a k ,a n d B . T . Е а t o n . 2 0 0 6 . иs Disеаsеs|2: |8З4-1840. t n d е n ri г o n m е n t a rl i s k f а с t o r s i n Мediсillе l0: 570_576. l n o t Г ) а г ritn i а n l r l е d i с i n е . э Ссlеuolиtioп of Pеoplе апd }07.origins of mаjor Ьuman iаsiс' translational,zrndсliniсal :soсiаtiсln 29 4: 1З 52-1З 5 8.

Thе quеstion that I shаll ехаminе in this еssay is thе rеlation Ьеtwееn form and funсtion in еvolution' and how thе оrigin of diffеrеnt forrтs is undеrstoоd. Form hаs пvo aspесts:slrаpеor struсturе' as in tlrе morphologv of or. ganisms; and pattеrn in tinlе tlr Ьеlrirviсlr,suсh аs thе movеmеlrts of individual orgarrisms(swimming' walking, flying) or thе spatial pattеrns of сollесtivеs,suсh as floсks of Ьirds or fогaging сoloniеs of soсial insесts.Thеsе сhагtrсtеristiсs of spесiеsаrе oftеn rеfегrеdto сollесtivеly as сhаraсtеrs' and thеy havе аdirptivе, funсtiоnаl signifiс:.rnсе for tlrе survivаl of tlrе spесiеs. Howеvеr, thеrе is a distinсtion Ьеtwееn undеrstandingthе origin
.з00 Bеуoпd t|lе Dаrшiпiаn Pаrаdigtn еxamplеs that сan Ье usеd fгorn animаl moгphoiogy alld сollесtive Ьеhavior pattеrns' somе of whiсh I disсuss, Ьut thе plаnt ехamplе mаkеs thе gеrrеral poiпts сlеarly and illustratеs how thе argumеnt tЬat rеlatеs to morphology сan Ье pursuеd in otlrеr с:rses. Tlrе sесond typе сlf еvidеnсе that I prеsеnt fсlr сonstraints сln tlrе possiblе forms availaЬlе for еvolution сomеs from tЬе nаturе ilf thе proсеssеSthat gеnеrаtе thе forms. Thеsе arе thе dynaпriс aсtivitiеs whеrеЬy diffеrеnt morphologiеs and Ьеhаviors arе gеnеrаtedЬy intеraсtionswithin orgаnismsduring thеir dеvеlopmеnt and Ьеtwееrr.thеrnin prоdr.rсingЬеhirvior pattеrns. This involvеs somе еlеmеnt of thеorеtiсаl modеling, showing what typеsof proсеssеS сor'rld givе risе to tЬе fсlгпrs аrrd rr,lry гhеsе геsult in disсrеtе,nol сontinuous' variation in сharaсtеrs. Thе viеwpсlint pгеsеntеdhеге in no sеl.lsесhallеr.rgеs tЬе irr-rportanсе o{ natural sеlесtionirr еvolution. Whеthеr thе fсlrms оf organisms arе initiаlly gеnеratеd as distinсt pоssiЬilitiеsor as a сontinuum of variations, sеlесtionstill opеratеs to influеnсе thе frеquеnсy of thе diffеrеnt forms асс
Phyllоtaхis as a Sеlf-organizing Growth Proсеss A сlassiс ехamplе оf form in flowеring plants сonсеrns thе arrangеmеntof lеavеsalorrgthе stеn-r(phyllotaxis).It has Ьееn rесognizedfor lnany yеarsthat t h е r еa г е o l l l y r h r е ер г i m a г 1 .с.( ) l n m ( ) n P а t t е r n s r. h o u g ht h е r еа r е а I s os o m еi n frеquеntly found arrangеmеnts. Thе rnajor arrangеmеnts аrе shown in Figure 1. Thе first of thеsе has thе forпr of a spirаl whеll onе looks dorvn on thе plant, illustratеd hеrе Ьy yuссa. Suссеssivеlеavеs oссu1.lyp()sitionsrotatеd throrrgh а wеll.dеfinеd avеragе anglе (l37.5o) rеlativе to thе prеvious lеaf. Thе sесond pattеrn is сallеd wlrorlеd, in rvhiсl-rtwo Or tnorе lеаvеsarlsеаt еaсh nodе. Тhе lеavеsat еaсh suссеssivеnodе arе rotatеd so thаt thе lеavеsarе loсatеd аЬovе tlrе gаps сlf tlrе prеviсlusrvhorl. Thе еxamplе slrown is fusсhia' whiсh has two lеavеs at еaсh nodе' with rotation of suссеssivеrvhorls through

h \

Figurе 1. Thе tЬrе in fusсhia 1middlе)

90.. Tlrе tlrird pаt еaсh nodе аnd еaс fгom гhе prесеdin thе growing tip oI turеs Ьy growth al мoRPHoGl oF MoRPн

A сomрrеlrеnsivе Douady аnd Ссlrrd a modеl that shoц damеntal idеa is tl mordium lvill arir гegiоr-rfalls Ьеlow sourсеof inhiЬitio ing. Howеvеr' thе that as lеavеs gro. сan Ье initiatеd. It that rеsults in thе . mеristеm and its g terns of lеaf arrar ondary onеs. Tlrt pattеrning pгoсеss саl tеrms, еaсЬ of dynamiс proсеssl

Beуспd thе DаrшiпLlп Pаrаdigm )rphologyand сollесtivе Ьеhаvior plant еxamplе makеs thе gеnеral mеnt that rеiаtеs to rnorphology nt for сonstгaintsorr thе possiЬlе thе naturе tlf thе proсеssеs that aсtivitiеswhеrеЬv diffеrеnt morltеraсtionswithirr oгganisms durin prodtrсing Ьеhirvior рattеrns. nodеling, showing rvhat typеs of why thеsеrеsult ir-rdisсrеtе, not сhаllеngеsthе imp
,owthProсеss nts сonсеrnsthе arrangеmеnt of ln rесognizеdfor mаnу-уе:rrsthat r r s .г h o u r . ht h е г еа г е : t I s оs с r t l r еi t r rrangеmеntsarе slrown in F.igurе al whеn onе looks down on thе lеavеsoссupy positions rotatеd 5") rеlativеto thе prеvious lеaf. hiсhtwo ()r morе lеlvеs агisе at ] arе rotatеd so thаt tlrе lеаvеs arе l. Thе ехamplе shoц,rr is fusсhia, rion of suссеssivеwhorls thrоugh

Еigurе1. Thе thrr..е typеsof phyllotaхis:spiгal' as in yuссa (/eЁ/;dесrrssаtе' as in fusсlriа (midrlla);and distiсhсlus,as in rл,,lizе(right).

90.. Thе third pattеrn is knorvn lls сlistiсhоtrs,in r,l,lriсlrthеге is a singlе lеaf at еaсh nodе аlld еirсh suссеssivеlеаf is loсirtеdon thе oppositе sidе of thе sfеm from thе prесеding сlnе. Thе gеnеratoГсlf all thеsе pattеrns is tlrе lnеristеm, thе growing tip of thе plant' whеге thе lеirvеsarе produсеd as distinсt struсturеsЬy growth and diffеrеntiationсlf сеIlsin intеraсtion with onе anothеr. MoRPHoGENEт|с FIЕLDs As GЕNЕRAтoRs oF МoRPHoLoGY A сomprеlrеtrsivееxaminatitln of tllе gеnеrativеproсеss in thе пrеristеmlеd Douady аnd Сoudеr (1996) to synthеsizеthе сomponеnts of this proсеss intсl a modеl that slrtlws how thе thrее typеs of phyllotахis сould oссur. Thе fundamеntаlidеa is that thе mеristеm is a doпlain of grоwth in whiсh a lеaf primordium will arisе only if thе сonсеntration of аn inhiЬitory fiеlсl in this rеgion falls Ьеl
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З02

Beуoпd the Dаrluiпiаn Pаrаdigm morphogеnеtiс fiеld for partiсular initial and Ьoundary сonditions thatproduсеs a partiсular form. What сan this modеl rеvеal aЬout distinсtionsamong thе thrее majorphyl. lotaхis сatеgoriеs?It is known that spiral pattеrns oссur in just ovеr 80%of highег plant spесiеs. Thе initial lеaf pattеrn in thе sееdlings of all thеsе spесiеs is еithеr onе storagе lеaf, as in monoсotylеdons, or two' as in di. .lfhat сotylеdons. еmеrgеs from thе work of Douady and Сoudеr is that with thеsе initial сonditions on thе fiеld organization of thе mеristеm, spiral phyllotaхis is thе pattеrn that is most aссеssiЬle(it is thе attraсtor that liеsonthе main Ьranсh of thе dynamiс gеnеrator).Furthеrmorе' thе divеrgеnсеanglе bеtwееn suссеssivеlеavеsсonvеrgеSon thе oЬsеrvеd anglе of 137.5. onthis Ьranсh of thе pattеrn-gеnеrationproсеss.Thе othеr spiral pattеrnsoЬsеrvеd infrеquеntly, with diffеrеnt divеrgеnсе anglеs' arе aссеssiЬlе,Ьut thеy rеquirе that paramеtеrs in thе modеl havе spесifiс rangеs' as do rarе whorlеd рattеrns. Diffеrеnt plant spесiеs сan thеrеforе havе diffеrеnt phyllotaхis pattеrns as a rеsult of gеnеtiс influеnсеson initial сonditions and paramеtеrvaluеsin thе mеristеm, Ьut thеrе is an ovеrаll Ьias in thе dirесtion of spirals,as ob. sегvеdin nаturеМoRPHoGЕNЕт|с FlELDS PRoDUсЕ FoRMs WlтH MAтHEМAт|сAL RЕGULAR|тlЕs Plants with spiral phyllotaхis havе a сharaсtеristiс mathеmatiсal ordеrin thе spatial rеlationships of thеir lеavеs.Somе ехаmplеs of thеsе arе givеnin Figurе 2, whiсh shows thе spiral arrangеmеnts of lеavеs in Аrаuсаriа ехсelsа, a mеmЬеr of thе Мonkeу Puzz|e family. Thе numЬеrs on thе lеavеsrеfеrto thе sеquеnсе in whiсh thеy wеrе gеnеratеd, 1 Ьеing thе yоungеst lеaf or thе last to Ье gеnеratеd,2 tЬe prеvious lеaf, and so on. Thе spirals in this figurе arе drawn through lеavеs that makе dirесt сontaсt with еaсh othеr. Now look at thе diffеrеnсе Ьеtwееn thе numЬеrs of suссеssivе lеavеs along any spiral. In Figurе 2atЬe diffеrеnсеsarе 8 along thе spirals dеfinеd Ьy dottеd linеsand 13 for diffеrеnсеs along spirals with solid linеs. This dеfinеs what is knownas (8' 13) spiral phyllotaxis. Thе othеr two еxamplеs in thе figurе havе (5,8) and (З, 5) spiral phyllotaхis (Figurеs2Ь and 2с' rеspесtivеly).Thе numЬеrsin thеsе pairs,3' 5, 8, and 13, Ьеlong to a wеll-known mathematiсalsеriеsdеfinеd as Пi * 1= n + п _| еaсh suссеssivеnumЬеr of thе sеriеsis thе sum of thе two prесеding numЬеrs. Thе pагtiсulаr numЬеrs of thе sеriеs dеpеnd on thе two numЬеrs that start it. If wе Ьеgin with thе numЬеrs 1, 1' thе sеriеsis 1,1, 2, з, 5,8, 13,21,34, 55, and so on. Most plants with spiral phyllotaхis Ьеlong to spirals dеfinеd by suссеssivе numЬеrs in this sеriеs, as wе sawln Figurе 2 for thе Мonkеy Puzz|e trее. Douady аnd Сoudеr (1996| showеd that thеsе arе thе spirals that arisе on thе main Ьranсh of thе gеnеrativеproсеss in thеir mоdеl. Нowеvеr, spirals with numЬеr diffеrеnсеsЬеlongingto o t h е r F i Ь o n a с с i s е r i е sa r е a l s o f o u n d i n n a t u r е ' s u с h a s ( 2 , 2 , 4 , 6 , 1 0 , 1 6 , 2 6 , . . . ) , ( 2 , 5 , 7 , 1 2 , 1 9 , 4 \ , 6 8 , . . . ) , а n d ( З , 4 , 7 , 1 0 , 1 7 , 2 7 , 4 4 ,. , , ) . Thеsе сan arisе from thе dominant spiral Ьranсh Ьy spесifying partiсular initiаl

Figure 2. Leaf arrangе Arаuсаriа ехсеlsа. See

tl аnd Ьoundary сondititlns that pro-

Bеуond the Dаrtuiltiап Pаrаdi,qm

inсtions аrnong thе rhrее rrlajor phylal pаttсrrls| )attеrn in thе sееdlings of аll thеsе t nlоnoссltyiеdorrs, or two' аs in dik of Douadv and Coudеr is that with nizаtionof thе mегistепr,spiral phyliЬlе (it is thе attraсtor thаt liеs on thе ) . F u r г l r е r m о r еt'h е d i v е г g е n с еа n g I е thе сlЬsеrvеdanglе of |З7.5" on tйis ;s.Thе othег spiral pattеrns oЬsеrvеd nglеs,аrе ассеssiЬlе,Ьut thе},rеquirе :ifiс rangеs,as do rarе whorlеd patlrе hаvе diffеrеntphyllotаxis pattеrns rl сonditionsаnd paramеtеr valuеs in ras in thе dirесtion oi spirals, as oЬ-

)DUсЕFoRМs WlтH

s

:haraсtеristiсmаthеmatiсal ordеr in S o m ее х a m p l е so f t h е s еа r е g i v е n i n ]mеntsof lеаvеsin Аrаuсаriа ехсеlsа, ,. Thе numЬеrs on thе lеаvеs геfеr to rtеd' 1 Ьеirrgthе yсlungеstlеaf or thе ', and so on. Thе sрirals in this figurе ,сtсontасгwith еaсh othеr. Now look of suссеssivеlеavеsаlolrg any spiral. .hеspiralsdеfinеdЬy dottеd linеs and c linеs.This dеfinеswhar is knor,vnas 'o ехamplеs in thе figurе hаvе (5, 8) rnd 2с' rеspесtivеly).Thе nLrmЬеrsin wеll.known mаthеmatiсal sеriеs dе. lunrЬеrof thе sегiеsis thе sum of thе numЬеrsof thе sеriеs dеpеnd on thе :hthе nunrbеrs1, 1, thе sеriеs is 1, 1' Мost plants with sрiral phyllotaхis t u n r Ь е r si п t l l i s s е r i е s 'а s w е s а w i n ) o u a d Уа n d С o u d е r ( 1 9 9 6 ) s h o w е d : m а i n b r n n с ho f г h е g е n е г а t i v еp г o th nlrrnЬеr diffеrеnсеs Ьеlongirrg to n a t u r е 's r r с ha s ( 2 , 2 , 4 , 6 , 7 0 , 7 6 , a n d ( 3 ,4 , 7 , 1 0 , 1 7 , 2 7 , 4 4 , . . . ) . lranсhЬy spесifyingpartiсular initial

Figure2. Lеaf arrarrgеmеntson Ьranсhеs of а spесiеsof Мonkеy Puzzlе trее, Аrаuсаriаeхcеlsа.Sее tехt for disсr.lssiorr.

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Bеуoпd thе Dапt'iпiап Pаrаdigm сonditions and pаramеtеr vаluеs in thе mоdеl of Douady and Coudеr. Thе rarе pаttеrns
and Coudеr. Thе |atге morphogеn from а lеa nеw lеaf to form аt a еvidеnсе prеsеntеd Ьy duсtion of primordiur auхin that gеtstransp mation in its nеighЬоr is thus rеplaсеd Ьy rеrт inhiЬitory асtion Ьy а vегtеd so that instеad . lеaf formation in a sсl phogеn thаt induсеs l. nеw lеaf and its bounс nеw lеaf inititation irr a fiеld of inhiЬition Ье еrns whеrе thе pеaks o port of thе morphogеn Thе еlеgаnt studiе moгphogеnеtiс fiеlds iI tions. Сlеarly thеy dо r modеl of thе wholе а dirесtional-fiеld сompt tial loсation of аuхin 1 that is loсalizеd to thе t r a n s p o r t i n ga u х i n а p i vasсular сеlls of thе dе еnсе that undеrliеs thе to Ье explainеd in tеrm morphogеnеtiс fiеld. lV aсross сеll walls, сеll d m е г i s t е mt o p г o d u с е t l oЬsеrvеd in lеaf phyllс sееk to providе аn int Proсеss. Clеarly any r aсhiеvе thе samе rangr аnd thеi r transt.ormar DЕvЕLoPMЕNт вЕтWЕЕN oRl(

I now turn to thе issuе plaining aspесts of phy usеd to dеfinе thе adaр ism funсtions in a par with othеr nrеmЬеrs o{ t o t h е с h a r а с r e r so f а n

modеl of Douаdy and Сoudеr. Thс е n t st h l t l r е t ] i s г i l l с t i v еt t l p а r t i с u I а r I whеn spесifiс Ьoundary сonditions .сingthеsе modеs to аppеaг, though otlеs iп tеrпrs of paсking dеrrsity of

jRЕNт PHYLLoтAст|с FoRМs :l of Drluаdyand Сoudеr аrе staЬlе al соnditions on thе пrсlrplrogеnеtiс is sеnsirivеtо сhаngс.sin thеsе than f Figurе 1 arе thе onеs thаt aге lеаst сondititlnsiп thе rnodеi, arld aпlong roЬust. This liеld modеl of thе dyгеmthus providеs rrs with а possiЬlе f pаttеrnsсan Ье gеrrеrirtеdin higlrеr riсturеof how thе diffЪrеnt pattеrns j p r o с е s su n d е r v a r i a t i o n in thе gеnl diffеrеrrtgеnе aсtivitiеs аnd Ьoundсltsand diсots).It is nсlt nесеssary or ral sеlесtionоr diffеrentiаl fitnеss of lvеd rаngе of fortns сouid havе origus is that within somе plant linеagе lеristеmа dvnaшiс ргoсеss with thе his modеl gеnеrаtеs tlrosе аnd oniy rrt spссiсs. Тhеге arе many pattеrns l L r с е ds,u с h а s a s i n g l е l е a f a t а n o d е ' ldе, thrееаt thе nехt rotаtеd rеlativе sеquеnсе.Tlrеsе arе nеvеr oЬsеrvеd. a n v i r n l g i n l Ь | е\ е t o r i l с o l l t i n u u m rсеssеsof tlrе typеs thаt oссur in dе:t of fсlrmsассеssiЬlеto thе dynаmiс ,сtionthat dеfinеs thеsе possiЬilitiеs, ]аtlvеpГoсеssin thе dеvеlopirrg or]nеtiсproсеssеsis wlrаt providеs us . spесiеs аs distinсtforшs ассеssiblе

ЕRAтoRs эudеr slrows what prinсiplеs arе rе-'n ot phyllotaxis, Ьut it operаtеs at tudiеsЬ1.Rеinlrardt еt аl. (2003) ind i n g е r l е r l t i n gp h y l l o t а с t i сp а t t е r n s зtail from that assuпlеd Ьy Dоuady

Beу'oпdtbе Dаru,,iпiаttPаrаdigm andСoudеr. Thе lattеr assumеd an inhibitory influеnсе,possiЬly сarriеd Ьy a morphogеnfrom a lеaf primordium, that dесrеasеswith distanсе,allowing a nеw lеаf to form аt а сritiсal distаnсе from a dеvеloping lеаf. Howеvеr' thе еvidеnсеprеsеntеdЬy Rеinhardt and сollеaguеs is that thе influеnсе is an induсtion of primordium formation Ьy auхin. A nеw lеаf асts аs a sink for auхin tЬаt gеts tгanspoгtеd away from tЬе sitе, thus prеvеntin8 nеw lеaf formationin its nеighЬогhood.Thе irrhiЬitio.' Dou,jy and Coudеr ",.u,n.dЪy isthus rеplaсеd Ьy rеmoval of an induсеr from thе nеw lеaf rathеr than dirесt inhiЬitory aсtion Ьy a morphogеn. The fiеld rulе is thеrеforе еffесtivеiy invеrtеdso that instеаd of pеrmissivе rеgions of low inhiЬition that all
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Bеуoпd the Dаrtuiпiап Pаrаdigm plants' pigmеntation pattеrns and shapеs of lеavеs)and to thе lifе сyсlе as a wholе. Natural sеleсtion is gеnегally takеn to dеsсriЬе thе proсеss whеrеЬy organisms with сhirraсtеrsadaptеd to thеir haЬitat arisе in thе сoursе of еvolution: organisms with diffеrеnt hеrеditary сharaсtеrs arisе as a rеsult of gеnеtiс variation' and thе rnorе adaptivе (fittеr) сharaсtеrs inсrеasе in frеqrrеnсy in thе population rеlativе to thosе сharaсtеrs that arе lеss fit. Thе сharaсtеrs oЬsеrvеd most frеquеntly in spесiеsarе thеrеforе rеgаrdеd as having grеatеr funсtional valr.lеto thе organism' so that thе diffеrеntial aЬundanсе of a сharaсtеr is takеn as a mеasurе of its adaptivе valuе to thе organism.If wе apply this rеаsoning to thе frеquеnсy of phyllotaxis pattеrns in thе lеavеs of highеr plants, Wе may сonсludе that spiral phyllotaхis is tlrе pattеrn with highеst fitnеss or utility to thе lifе сyсlеs of highеr plant spесiеs, sinсе this is thе most aЬundant pattеrn' takеn to Ье еstaЬlishеd historiсаlly Ьy natural sеlесtion. What is thе sеlесtivе valuе of lеaf arrаngеmеntsin plants? A rеasonablе suggеstionis that lеаvеssеrvе thе funсtion of сatсhing light for photosynthеsis: thе diffеrеnt pattеrns of lеavеs on a stеm havе diffеrеnсеs in thе еffiсiеnсy with whiсh thеy сatсh photons' whiсh dеpеnds оn how muсh thеy ovеrlap and shadе onе anothеr. Studiеs havе shown that thе spiral pattеrn illustratеd Ьy yuссa in Figurе 1a has thе lеast mutual shading whеn light is сoming from dirесtly ovеrhеad' sinсе lеavеs that aге arrangеd in rows nесеssаrily shadе onе anothеf (Figurеs 1Ь and 1с). This сould bе a Ьasis foг undеrstandingthе diffеrеntial aЬundanсе of lеaf phyllotахеs in tегms of natural sеlесtionand funсtion. Howеvеr, whеn othеr faсtors arе сonsidеrеd, this proposal losеsits .sfhеn avеrаgеd ovеr thе сoursе of a day' with thе sun oссupуing all strеngth. angular positions rеlativе to thе plant' thе diffеrеnсеs Ьеtwееn diffеrеnt lеaf arrangеmеnts with rеgard to shading Ьесomе minimal. Furthеrmorе, obsеrvation of spесiеs in diffеrеnt haЬitats shоws that thеrе is no сorrеlation Ьеtwееn shadе plants and spiral phyllotaxis, as might Ье еxpесtеd if maximization of light сaPturе сorrеlatеdwitlr spiral lеaf arrangеmеnt.Plant adaptation to shadе is largеly through vаriation in lеaf shapе аnd pigmеntation; thе lattеr inсrеasеs aЬsorption of thе light frеquеnсiеs availaЬlе. Thе ovеrall еvidеnсе is that phуllotaсtiс pattеrn is sеlесtivеly nеutral in plants, sinсе all thе diffеrеnt pattеrns arе oЬsеrvеd in various light haЬitats. In this сasе diffеrеntiаl aЬundanсе, thе prеdominanсе of spiral phyllotaxis in lrighеr plants, dоеs not appеar to bе еxplainеd Ьy natural sеlесtionof a funсtional сharaсtеr. If thе сonсlusion is сoгrесt that all phyllotaсtiс pattеrпSwork adеquatеly for thе photosynthеtiс nееds of plants, thеn spirals prеdominatе Ьесausеthеy arе dеvеlopmеntallymorе aссеssiЬlеand staЬlе. Thеrе is nothing surprising or proЬlеmatiс aЬout this сonсlusion. It mеans simply that wе nееd to takе ассount of thе rеlativе dеvеlopmеntal aссеssibility and staЬility of diffеrеnt morphologiсal pattеrns, whiсh will affесt thе frеquеnсy of сhara.tеrs in spесiеs and nruryhavе a primаry influеnсе in сasеs whеrе thе сhаraсtеrs arе sеlесtivеly 'Wе nеutral. сannot simply assumе that diffеrеntial aЬundаnсе is alwaysехplainеd Ьy natural sеlесtiоn.Of сoursе, it is аlways assumed that if a сhаraсtеr gеnеratеd in a spесiеs is not usеful' it will not inсrеasе in frеquеnсy, andif

it is a disadvantаg tеrminеs сliffЪrеnti;

Сollесtivе Bеhа

Thе Ьеhаvioг pilttе aspесt of thеir еvo| sесts to ftrri.rgеfсrr lеavеs in tЬе autum Just as thеге arе di arе diffеrеnсеs in t] signifiсant irrс]iса s p е с i е s .I s h а l l n o w tеrns аs Ьiolrlgiсal namiс ordеr in an l dеvеlopmеnt arе kе In this сhаmЬеr th young' fееdirlg and and kееping tlrе Ьrt inеd сoloniеs kеpt i aсtivity pаttеrn am of ants. Whеn ind thеir fеllows or at thеm' it was showl of thе tеrm (Glеiсk

rhythm throughout .sИhеге als? doеs thс Nigеl Fгanks rrnс in a сolony of ants с thе young in tЬе Ь aсtivity-inaсtivity с about 10 minutеs е individually pеriod сhamЬеr thеsе с}'сl wholе ехhiЬits :r rе in thе flaslring of fi full moon. Н
Bеуoпd thе Dаrшiniаn Pаrаdigm of lеavеs)and to thе lifе сyсlе as a еn to dеsсriЬеthе proсеss whеrеЬy ir haЬitat arisе in thе сoursе of еvoary сharaсtеrs arisе as a rеsult of э (fittеr)сharaсtеrs inсrеasе in frеlsе сharaсtеrs that afе lеss fit. Thе сiеs arе thеrеforеrеgardеd as having , so that thе diffеrеntial aЬundanсе s adaptivеvaluе to thе organism. If of phyllotaхis pattеrns in thе lеavеs piral phyllotaхis is thе pattеrn with of highеr plant spесiеs,sinсе this is еstaЬlishеdhistoriсally Ьy natural angеmеntsin plants? A rеasonablе n of сatсhing light for phоtosynthе. еm havе diffеrеnсеs in thе еffiсiеnсy lеpеnds on how muсh thеy ovеrlap лrnthat thе spiral pattеrn illustratеd l shading whеn light is сoming from arrangеd in rows nесеssarily shadе uld Ье a Ьаsis for undеrstanding thе эs in tеrms of natural sеlесtion and rе сonsidеrеd,this proposal losеs its of a day, with thе sun oссupying all rе diffеrеnсеsЬеtwееn diffеrеnt lеaf сomе minimal. Furthеrmorе, oЬsеrshows that thеrе is no сorrеlation axis, as might Ье ехpесtеd if maхispiral lеaf arrangеmеnt.Plant adapi o n i n l е a f s h а p еa n d p i g m е n t a t i o n ; ht frеquеnсiеsavailablе. Thе ovеrall еlесtivеly nеutral in plants, sinсе all rious light haЬitats.In this сasе diflf spiral phyllotaхis in highеr plants, rral sеlесtiоn of a funсtional сharaсhyllotaсtiс pattеrns work adеquatеly rеnspiralsprеdominate Ьесausе thеy l stаЬlеT . hеrе is notЬing suгprising ' mеans simply that wе nееd to takе ссеssiЬility and staЬility of diffеrеnt thе frеquеnсyof сharaсtеrsin speсiеs :s whеrе thе сharaсtеrs arе sеlесtivеly diffеrеntial aЬundanсе is always еxit is always assumеdthat if a сharaсwill not inсrеasеin frеquеnсy' and if

it is a disadvantagе,it will nсlt survivе. Howеvеr, it may not Ье utility that dеtеrminеsdiffеrеntial aЬundanсе.

СollесtivеBеhavior in Ant Coloniеs Thе Ьеhavior pattеrns of orgarrismsarе сlеarly an important and intеrеsting aspесtof thеir еvolution. Thе abilitiеs of fish to swim, of Ьirds to fly, of insесtsto foragе for food' and of plants in tеmpеratе сlimatеs to drop thеir lеavеsin thе autumn all сontriЬutе signifiсantlyto thеir сapaсity for survival. Just as thеrе arе diffеrеnсеsЬеtwееn spесiеsin thеir morphologiеs, so thеrе arе diffеrеnсеsin thеir Ьеhavior pattеrns that allow us to rесognizе thеm as signifiсant indiсators of thе distinсtivе lifеstylеs and haЬits of diffеrеnt spесiеs.I shall now takе a look at thе way Wе сan undеrstand Ьеhavioral pattеrnsas Ьiologiсal forms. For this I usе an еxamplе from thе study of dynamiс ordеr in an ant сolony. Thе quееn and thе young ants at all stagеsof dеvеlopmеntarе kеpt in a spасе within thе сolony сallеd thе Ьrood сhamЬеr. In this сhambеr thеrе aге many workеr ants that tеnd thе quееn and thе young' fееding and сlеaning thеm, moving thеm аЬout as thе young maturе' and kееping thе Ьrood сhamЬеr frее of dеЬris. Rеsеarсhеrswho havе еХaminеdсoloniеs kеpt in laЬoratоriеshavе oЬsеrvеdthе oссurrеnсеof a rhythmiс aсtivitypattеrn among thе workеrs in thе Ьrood сhamЬеr of сеrtain spесiеs of ants. Whеn individual workеrs Wеrе oЬsеrvеd, еithеr in isolation from thеir fеllows or at low dеnsity so that thеrе wеrе fеw intеraсtions Ьеtwееn thеm, it was shown that thеir Ьеhavior was сhaotiс in thе tесhniсal sеnsе of thе tеrm (Glеiсk 1998). Thе quеstion arisеs:how doеs a rеgular pеriodiс rhythmthroughout a сolony arisе from thе intеraсtions of сhaotiс individuals?Whеrе doеs thе ordеr сomе from? Nigеl Franks and сollеaguеs(Franks et,a|' 1990) oЬservеdthat thе workеrs in a сolony of ants оf thе gеnus Lе|ltothorах who wеrе tеnding thе quееn and thе young in thе Ьrood сhamЬеr еxhibitеd a wеll-dеfinеd rhythm in thеir aсtivity-inaсtivityсyсlеs. Roughly spеaking, thе workеrs wеrе inaсtivе for about 10 minutеs еvеry half hour. Thе first assumption wаs that еaсh ant is individually pеriodiс in its aсtivity-inасtivity сyсlе, and that in thе Ьrood сhamЬеrthеsе сyсlеs Ьесomе synсhronizеd through intеraсtions so that thе wholе ехhiЬits a rеgular pеriodiс сyсlе. Suсh synсhronization is wеll known in thе flashing of firеfliеsor in fеmalе monkеys сoming into еstrus with thе full moоn. Howеvеr, whеn Сolе (1991r\еxaminеd thе Ьеhavior of individual аntsfrom сoloniеs of a spесiеsсlosеly rеlatеd to that studiеd Ьy Franks еt al. (1990)'whiсh also ехhibitеd rhythmiс Ьеhаvior in thе Ьrood сhamЬеr, hе found that thеir aсtivity-inaсtivity сyсlеs wеrе tесhniсally сhaotiс: thеy ехhiЬitеddеtеrministiс сhaos, without any sign of a rеgular rhythm. How' thеn,doеs a rеgular pеriodiсity еmergе frсlm thе intеraсtion of сhаotiс individuals? This proЬlеm was studiеd Ьy Solё еt аl. (199З) Ьy сonstruсting a сomputеr modеlof thе intеraсtion of ants in a Ьrood сhamЬеr. Еaсh individual modеl

З07

Bеуoпd thе Dаrшiпiап Pаrаdigm ant Wаs dеsсribеd in its aсtivity-inaсtivitybеhaviсlras сhaotiс, in aссоrdanсе with thе ехpеrimеntal еvidеnсе, and thе modеl ants intеraсtеd with еaсh othеr by еХсitation,again in aссordanсеwith oЬsеrvation:if an aсtivе ant intеraсts with an aсtivе or an inaсtivе ant, Ьoth сasеs rеsult in inсrеasеdaсtivity. Thе modеl Was сonstruсtеd as a kind of moЬilе nеural nеtwork in whiсh ants playеd thе rolе of ехсitаЬlе nеurons that сould movе arollnd on a grid that rеprеsеntеdthе Ьrood сhаmЬеr. lt Was not possiblе to prеdiсt thе outсomе of thе modеl, sinсе thеrе Was no rеason to assumеthat сhaotiс individuals that intеraсtеd Ьy еxсitation would dеvеlop a сohеrеnt rhythm. Howеvеr, that is prесisеly what oссurrеd. }.urthеrmorе,thе modеl also сonformеd to oЬsеrvations that wеrе not Ьuilt into thе modеl: a rеgular pеriodiсity еmеrgеs in thе ant сolony only whеn thе dеnsity of ants ехсееdsa сritiсаl lеvеl, as oЬsеrvеd Ьy Сolе (199|) in his ехpеrimеntаlstudiеs.Thе pеriodiсity еmеrgеsquitе suddеnly aЬovе thе сritiсal dеnsity;in tесhniсaltеrms, it has thе сharaсtеristiсsof a phasе transition, likе thе suddеn сondеnsation of a gas to a liquid at a сritiсal tеmperaturе,so that onе kind of ordеr suddеnly rеplaсеsanothеr. It is intеrеstingto ask what kind of ехplanation of thе еmеrgеntpropеrty this modеl givеs us. sЕЕKlNG AN EХPLANAтIoN FoR тHЕ FoRМ Thе еmеrgеntpеriodiсity in thе Ьrood сhamЬеr сannot Ье rеduсеd to thе bеhavior of thе individual ants and thеir intеraсtions in any spесifiс сausal sеnsе.That is, knowing aЬout Ьеhavior of individual ants and thе naturе of thеir intеraсtions is not suffiсiеnt to prеdiсt thе pеriodiс Ьеhavior of thе wholе сolony. Nеvеrthеlеss,this pеriodiсity is a сonsistеnt propеrty сlf thе modеl aЬovе a сritiсal dеnsity of ants. Hеrе is a сasе of сonsistеnсywithout сausаl rеduсtion, whiсh is found in many сasеsof еmеrgеnсеin сomplеx systеms. It mаy wеll Ье that mathеmatiсal thеorеms will Ье disсovеrеdthat allow onе to mаkе prеdiсtiоns aЬout suсh systеms.Howеvеr' thеsе wеrе not .What known at thе timе thе modеl Was сonstruсtеd. thе modеl makеs сlеaris thе nесеssary propеrtiеs for suсh an еmеrgеnt proсеss. Thе mathеmatiсal funсtions usеd in thе modеl dеsсriЬе thеsе propеrtiеs without ехplaining what thеir сonsеquеnсеsarе. This is typiсal of sсiеntifiс proсеdurе: models oftеn dеsсriЬеwithout giving сausal еxplanations of thе phеnomеna. Suсh modеls arе vеry usеful in сlarifying variоus aspесtsof еmergеntprop. еrtiеs in сomplеx еvolving systеms.In partiсular, Wе сan ask what rolе natural sеlесtion might play in thе еrnеrgеnсеof rhythmiс aсtivity of workеrsin thе Ьrood сhamЬеr. To еxplorе this' wе nееd to ask what funсtion rhythmiс aсtivity has for thе сolony and how it sеrvеsits survival. Franks еt al. (1990) suggеstеdwhat this might Ье. Hе and othеrs havе oЬsеrvеd that if an aсtivе ant еnсountеrs an еmЬryo оr a larva that is alrеady gеtting attеntion from othеr workеrs, thе aсtivе workеr will go to anothеr mеrnЬеr of thе Ьrood. Thеrеforе, if workеrs in thе Ьrood сhamЬеr arе асtivе at thе sаmе timе, thеy proЬaЬly distriЬutе thеir сarе сlvеr thе Ьrood and thе quееn so that thеrеis littlе dupliсation of аttеntion. If thеir aсtivity pattеrns wеrе сhaotiс, thеn

somе еmЬryosоr lar dеnt of how thе worl S o l е ( l 9 9 9 ) h e v еs h o сolony aсtivity, pеriс саrе thаn сhаoriсpa miс сyсlеs of aсtivit lесtеd: thеy enhanсе whеn thеy arе dеvеl< p r o Ь a Ь l y w h y r h е s еl Flowеvеr, it is сlеа of thе rhythmiс aсti t i o n o f г h е г h y r h mp l undеrstаnding of hov w i t h t h е p r o p е r t i е s( orgапizаtioп iп Biol' rеvеlations of sеlf-or sеrvеd in naturе doеs arisе from thе rеpеat units.'' A4odеling thе : o f t h е p o s s i Ь i I i t yo f r } shows that thе dеnsit of mаximum dеnsiгy a widе rаngе of ехсi nomеnon to arisе in е m u s t Ь е г o Ь u s гi n г h еr еtеr valuеs in thе mod t o а w i d е г a n g ео f g е г faсt thаt thе rhythmа that it is not sеlесtеd t h е g r a d u a I i s tv i е w с l all Ьiologiсаi pгopеrt trаnsitions. Ьut сomp fеaturе of thе way Ьiо аnd Goodwin 2000). ЕMЕRGЕNт..o

It is thеsе spontanеo l 9 9 5 ) с a I l е d . . o r d еfr. miс morphology or Ьс in сomplеx living systе ditions arisе Ьy a rand d i v е r s i f i с a t i o nw i t h i n . inсluding thе oссurrеt f r o m d i v е r s i f i с а t i o no 1 vаriation of сondition

Bеуond thе Dаrшiпiап Pаrаdigm as сhаotiс' in aссordanсе Ьеhirviсlr : nlodеl аnts intеrасtеd with еaсh v i t ho Ь s е r v a t i o l li:i a n а с t i v е а n t i n Ьrlthсasеsrеsult in inсrеasеd aсtivof moЬilе nеural nеtwork in whiсh that сould movе аround on a grid yas not possiЬlе to prеdiсt thе outlson to assumеthi.rtсhaotiс individ,uld dеvеlop a сohеrеnt rhythnr. '. }.urthеrmоrе,thе model also сonrilt into thе modеl: a rеgular pеrio_ ,.hеrrthе dеnsity сlf arrts еxсееds а in his ехpегimеntаlsrudiеs.Thе pе_ ir-rtесhniсаl tегms' е сritiсaldеrrsit1'; ;ition,likе thе suddеn сondеnsation :urе'so that tlnе kind of ordеr sudаsk what kind of ехplanation of thе

R тHЕ FoRM ramЬеrсannot Ье rеduсеd to thе bе_ intеraсtionsin any spесifiс сausal of individual аnts аnd thе nаtuге of геdiсt thе pеriodiс Ьеhavior of tlrе iсity is a сonsistеnt propеrty of thе [еrеis a сasе of сonsistеnсy without l саsеsof еmеrgеnсеin сomplеx sys_ will bе disсovеrеd that аl_ thеorеtrrs 1 sуstеms.Horvеvеrothеsе wеrе not rсtеd.What thе modеl makеs сlеar is nеrgеnt proсеss. Thе mathеmatiсal :hеsеpropеrtiеs witlrout ехplaining эiсаl of sсiеntifiсproсеdurе: modеls laniltitrnsof thе phеnomеna. ng various aspесtsof еmеrgent proptrtiсular,Wе сan аsk what rolе natuе of rhythmiс aсtivity of woгkеrs in nееdto ask what furrсtion rhythmiс rvеsits sr:rvivаl.Fгаnks еt al. (] 990) thеrshavе oЬsеrvеd thаt if an aсtivе r e t i s a l r е a d yg е t t i I t gа t r е n t i o n f г o m o to anothеr mеmЬеr of thе Ьrood. rЬеrаrе aсtivе at thе samе timе, thеy lrood irnd thе quееn so that thеrе is асtivity pattеrns rvеrе сlrаotiс, thеn

sonrееmЬryosor lаrvaе might gеt morе attеntion than othеrs simply Ьy eссidеntof how thе workеrs wеге distriЬutеd in thе Ьгood сhamЬеr' Dеlgado and 5o16(1999)havе shown that whеn this is modеlеd Ьy сomputеr simulation of сolony aсtivity, pеriodiс pattеrns do indееd produсе morе еvеnly distriЬutеd сaIеthan сhaotiс pattеrns. So wе lravе a possiЬlе ехplanation of why rhythmiс сyсlеs of aсtivity in thе Ьrood сhаmЬеr arе bеnеfiсial аnd may Ье sеlесtеd:thеy еnhanсе thе survivаl сhanсеs of thе yourrg Ьy virtuе of good сaге whеn thеy arе dеvеloping, and sсr inсrеasе thе fitnеss сlf thе сolony. This is proЬaЬlywhy thеsе aсtivity сyсlеs arе сommonly oЬsеrvеd in suсh сoloniеs. Howеvеr, it is сlеar that natural sеlесtion in no sеnsе ехplains thе origin of thе rhythmiс aсtivity pattеrn in thе Ьrood сhamЬеr. Thе possiЬlе funсtiоn of thе rhythm plаyеd no rоlе in dеsigning thе modеl' whiсh providеs an undеrstandingof how rhythпriс aсtivity pattегl]sсa11еmеrgе in аn аnt сolony with thе propегtiеs oЬsеrvеd. As statеd in thе сomprеhеnsivе volumе Seff..Onе of thе orgапizаtioп iп Biologiсаl Sуstеms (Сamazinе еt al. 2001, 89): rеvеlationsof sеlf.organization studiеs is that thе riсhnеss of struсturеs oЬ. sеrvеdin naturе doеs not rеquirе a сomparaЬlе riсhnеss in thе gеnomе Ьut сan аrisеfrom thе rеpеаtеdappliсation оf sirnplе rulеs Ьy largе numЬеrs of suЬunits,''Мodеling thе ant сolony as а сomplеx systеlll providеs a dеmonstгаtion of thе possiЬilityоf rhythmiс Ьеhavior in thе Ьrood сhamЬеr. Furtlrеrmorе,it showsthat thе dеnsity rеquirеd for rhythmiс aсtivity is quitе low (aЬout 20% of maхimum dеnsity)' as oЬsеrvеd еxpеrimеntally,.rrrdthе rhythm аrisеs for a widе rangе of еxсitaЬility of thе irrrгs.This is what is rеquirеd for а phе. nomеnonto arisе in еvolution: it must сlссur fairly rеadily (Ье aссеssiЬlе)and mustЬе roЬust in thе sеnsеthat thеге should Ье a сorrsidеraЬlеrangе of param' еtеrvаluеs in thе пrodеl ovеr whiсlr thе phеnomеnon arisеs. This сoгrеsponds to a widе rangе of gеnotypеsin whiсh thе propеrty сan arisе. In addition, thе faсtthat thе rhythnr аrisеs suddеnly as a phasе transition in thе сolony means that it is not sеlесtеdgradually, with progrеssivеlyinсrеаsing dеfiniгion, аs .Wе сеrtаinly сannot say that thеgгadualistviеw of еvolution would havе it. all Ьiologiсalpropеrtiеsarisе in this suddеn, unеxpесtеdmannеr' as do phasе transitions,Ьut сomplехity thеory is dеmonstrating that this is a сommon fеaturеof thе way Ьiologiсal organization еmеrgеs(sееGoodwin 19941 So1ё аndGoodwin 2000). ЕMЕRGЕNт,.oRDЕR FoR FRЕЕ'' It is thеsе spontanеOus'roЬust еmеrgеnt propеrtiеs that Kauffman (1'993, thе proсluсtion of somе orgаnis1995)сallеd ..ordеr for frее'' in еvolr-rtion: miс morphology or Ьеlravior madе рсlssiЬlеЬy thе oссurrеnсе of сonditions in сomplехliving systеmsthаt allow thе propеrty to Ье gеnеrated.Thеsе сonditionsаrisе Ьy a random sеarсh of possiЬilitiеsthat rеsult from spontanеous divеrsifiсationwithin organisms Ьoth of gеnеs and of dynamiс possiЬilitiеs, inсludingthе oссurrеnсе of сhaotiс aсtivity' as wе havе sееn in ants' and fromdivеrsifiсationof еnvironmеntаl ссlnditions outsidе thе organism. Thе variationof сonс]itionswithin organisms and irr tlrеir еnviroпl-nеntsis what

t 1 0 Bеуtпtr]thе Dаrtuiпiап Pаrаdigпt Dzrrwin аssuпrесlt() gеllеratе hеrесlitirrl'!'ariеty within popr-rlаtionsаnd thе hаbitаt vаriеty t
Summary and Соnсlusions Form and funсtion hilvе always Ьееn сеntral сonсеpts usеd in Ьiology to 'Гhе urldеrstаnd orgаnisms ar-rdthеir еvolution. partiсular thеorу of еvolution dеvеlсlpеdЬy Dаrwin inсludеd Ьoth, Ьut thеrе has Ьееn a tеndеnсyto епrplrasizеthе rolе of ftrr-rсtion in dеsсriЬing holv organisms arе sЬapеdand thеir Ьеlrаvior is mсlldеd lry l.tаturalsеlесtiсln.A lrasiс assumption lras Ьееn tlrаt biologiсal fort-rrsvilry сontinLlousl,virs ll rеsult of random vаriаtion in gеnеs,arrсlit is naturаl sеlесtionthаt ..dесidеs''whiсh partiсular torms survivе аnd arе favorеd. Any disссlntinuitiеsof fсlrm Ьеtwееnеxisting spесiеsarе thеn rеgardеdas a rеsult of this sеlесtionproсеss'whiсh thеn ЬесomеstЬе sсulptor in еvolution. TЬе viеwpсlint dеsсriЬеdhеrе diffеrs frftlrgarrismsoftеn arisе аrsdistinсt fп-t еxpеrimеntal study, аnd from mtlсiеlsthat dеsсriЬе hсlrv diffеrеnt morpht>logiеsand Ьеhavior pattеrnsсаn aгisе fгtltп dynamiс proсеssеsrvithin аnd ЬеtrvееIrtlrtanisms. Тhеrе is nсl diffiсtrltyirr сomЬining nаttlrаl sеlесtionwirlr a disсrеtеsеtof pсlssiЬilitiеsfor еvolLrtionto woгk with. Distinсt forms still nееd to Ье tеstеd ioг thеiг survival valr"rс,аnd disсrimination геgarding funсtion сiln Ье mаdе among whatеvеr forms arе gеnеratеd,rеsultingin diffеrеntfrеquеnсiеsof thе fсrгms сorrеlating with diffеrеnt haЬitats. llowеvеr, undеrstanding thе primilr,vgеnеrativеorigins of thеsеforms nееdstо Ье distinguishеdfrom sесondаг,vsеlесtion pr()сеssеs.Ftlr геedеrs who wirnt to pursuе thе issuеs furthеr, goоd ovеrviеw с.lisсttssiсlns inсludе Сirt.nzrzitrе еt al. (200l), Arthur (2002), Wilkins (2002), anсl N1inеlli(2003). A nсlц,-сlаssiсdisсussionof сonstrаintsis Мayrrard Smith еt al. (l985). Phyllotaхis is disсussеd in Snow and Snоw

( 1 9 5 2 ) , A 4 i t с h i s o n( l 9 tion arе disсr-rssеdin (

tionary dеvеloprnеnt GilЬеrt et a|. (1996)' ) еthiсal pеrspесtivе, аr1 of сonvеntional sсiеnс tn Nаture's Dиe: Heаl

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Arthur, \й7.2002. Thе е dеvеlopmеntal Ьiol Сamazinе'S.,J.-L. Dеn B o b a Ь е а u2. 0 0 1 .S r PrinсеtonUnivеrsi С o l е , B . I . 1 9 9| . I s а n i г Proсееdiпgsof tbе l Dеlgado,J., and R. V. S сoloniеs.Jourпаlof Douady, S., аnd Y. Сou and III.Jourпаlof1 Franks,N. R., S. Bгvaп bеhaviourwithin th Маtbепаtiсаl Biсllг GilЬеrt,s. F.' J. lvI.opit dеvеlopmеntal Ьiol G l е i с k ,J . 1 9 9 8 .С h а o s : Vintаgе. G o o d w i n ,B . С . | 9 9 4 ' h and Niсolson. 2О07. Nаtцrc's] Books. G o r d o n ,D . М . | 9 9 9 ,А l York: Frее Prеss. Jеan, R.V. 1994. Phуllot Сambridgе:СamЬr Kаuffmаn,S. A. 1993.с Еuolution. Nеw Yor 1995.At Hrlпtе Маynard Smith,J.' R. B R. Lar-rdе, D. Rаup, еvolution. Quаrtеrl Мinеlli, t. 2О0З.Thе D' Еuolиtioп.СаmЬrid Мitсhison, G. 1972. PЬу Rеinhardt,D., Е..R. Pеs J. Traas,J. Frimi, аr аuхln trаnsPort.N.7 Salazar-Ciudаd,I.,.}.Jеr formatiоnin dеvеlo Sееlеy,T. D. |995. Thе Prеss.

Beусlпd thе Dаrъuiпiап Pаrаdigm Variеtywithin populations and thе Natural sеlесtion may ехplain thе f v n r i о u sf r l r l n s г h а r h а v е а r i s е n i n :hmiсaсtivity pattеrns in thе Ьrood rеr'thеrеarе situations in whiсh diftеrmsof thе dynamiсs of thе !]еnеrof thе diffеrеnt forms produсеd. In еvoluti()n'wе nееd to undеrstand at produсеthе distinсtivесharaсtеrr аnd thе еffесtsof natural sеlесtion lrs. Thе intеgrationof thеsе arеas of a сohеrеnt dynamiс piсturе of thе ionаry dеvеlopmеntаlЬiology.

еntral сonсеpts usеd in Ьiology to эn. Thе partiсular thеory of еvolut, Ьut thеrе has Ьееn a tеndеnсy to ling how organisms arе shаpеd and эtion. A Ьasiс assumptiсrnhas Ьееn а s e г е s u | ot f r а n d o m v a r i а г i o n i n idеs''whiсh partiсular forms survivе rm Ьеtwееnехisting spесiеs arе thеn lss,whiсh thеn Ьесomеsthе sсulptor .om this Ьy prеsеntingеvidеnсе that эf organismsoftеn arisе as distinсt of possiЬilitiеs.Furthеrmorе, thе inlrms prсlduсеdсan сontriЬutе to thе , so that natural sеlесtion is not thе iffеrеntialaЬundanсе.This еvidеnсе from ехpеrimеntаlstudy, and from lhologiеsar-rdЬеhavior pattеrns сan Ьеtwееnorganisms. гuralsеiесtionwith a disсrеtе sеt of )istinсt foгms stiil nееd to Ье tеstеd on rеgardingfunсtion сan Ье madе ulting in diffеrеnt frеquеnсiеs of thе i. FIoWеvеr,undеrstanding thе priеdsto Ье distinguishеdfrom sесondI Want to pursuе thе issuеs furthеr, a z i n ее t a l . ( 2 0 0 1 ) ,A r t h u r ( 2 О 0 2 ) , w-сlаssiсdisсussiсlnсlf сonstrаints is lis is disсussеdin Snow and Snow

(\952), Мitсhison (\972), and Jеan (1994), Soсial insесts and thеir organization arе disсussеdin Сolе (|99|), Sееlеy (1995)' and Goгdon (1999). Еvolutionary dеvеlopmеnt (also сolloquially known as еvo-dеvo) is thе topiс of GilЬеrt et aL' (1996). I disсuss thеsе issuеs, trying to put thеm into a Ьroadеr, еthiсalpеrspесtivе,arguing for a holistiс pеrspесtivе that rеquirеs a rеthinking of сonvеntional sсiеnсе tо aсhiеvе truе есologiсal harmony and sustainaЬility, inNаtиre's Due: НеаIiпg Оur Frаgmeпted Сulture (Goodwin 2007).

вlBLIoGRAPHY Arthur,w, 2002' Thе еmеrgingсonсеptualframеworkof еvolutionary dеvеlopmеntal Ьiolоgy.Nаturе 415z 757-764. Camazinе, S.'J.-L. Dеnеubourg, N. R. Franks,J. Snеyd,G. Thеraulaz,and Е. BoЬabеau.20О1. Self-orgапizаtioniп BiologiсаISуstеms.Prinсеton,NJ: PrinсеtonUnivеrsityPrеss. Сolе,B. J.199\.Is animalЬеhаviourсhaotiс?Еvidеnсеfrom thе aсtivityof ants. Proсeеdingsof thе Roуаl Soсiеtуof Loпdoп, SeriеsB 244:25З-259, Dеlgado'J.'and R. V. Solё.1999.Sеlf-synсhronizаtion and task fulfilmеntin ant сoloniеs.lourпаl of TheoretiсаIBklklgу 2О5: 433441.. Douady,S.,and Y. Сoudеr.1996.Phyllotaxisas a sеlf-organising proсеss.PartsI, II, and III.Jourпаl of TheoreticаlBiсllсlgу1'78:25 5-312. Franks,N. R., S. Bryant,R. Driffith,and L. Hеrnеrik.1990.Synсhronisation of Ьеhaviourwithin thе nеstsof thе ant Lеptothorахасеruorum.Bullеtiп of МаthеmаtiсаlBiologу 52 597_612. Gilbеrt,S. F.' J. M. Opitz, and R.A. Raff. 1996.Rеsуnthеsizing еvolutionaryand dеvеlopmеntal Ьiology.DеuеlopmепtаI Biologу \7 З: 357_372. Glеiсk,J. 1998. Сhаos:Тbе Аmаziпg Sсiепсeсlf the Uпprеdiсtаblе.London: Vintagе. .!Иеidеnfеld Goodwin,B. С. 1994.Holu the Leopаrd Сhапgеdlrs Spors'London: andNiсolsоn. 2007. Nаturе'sDuе: Hеаliпg Оиr FrаgmепtеdСulturе. ЕdinЬurgh:Floris Books. Gordon,D.NI. \999. Апts аt Work:Hotu ап lпsесtСoloпу ls Оrgапized.New York: FrееPrеss. Jеan,R.V. 1994,Phуllotахis:А SуstеmаtiсStudу iп PIапtМorphogепesis. СаmЬridgе:СamЬridgеUnivеrsityPrеss. Kauffman,s. A. 1993. Оrigiпs of Оrder: Self-Оrgаnizаtiсlп апd Sеlесtklпiп Еuolutioп.Nеw York: Oхford UnivеrsityPrеss. 1995.Аt Homе iп the Uпiuеrsе.Nеw York: Oxford UnivеrsityPrеss. MaynardSmith,J., R. Burian,S. Kauffman,P. AlЬеrсh'J. СаmpЬеll,B. Goodwin, R. Landе,D. Raup, and L..!Иolpеrt. 1985.Dеvеlopmеntal соnstraintsand еvоlution.Quаrtеrlу Rеuiеtaof Biologу 60 265-287. Мinеlli,A. 2003. The Deuеlopmепtof Апimаl Form: Опtсlgeпу,Мorpbologу, апd Еuolutioп.СamЬridgе:СаmЬridgеUnivеrsityPrеss. Mitсhison, G. 1972.Phyllotaxisand thе Fibonaссiseries.Sсiеncе,196:27О-275. Rеinhardt, D., Е.-R. Реsсoе,P. Stiеgеr'T. Мandеl, K. Baltеnspеrgеr, М. Bеnnеtt' Rеgulationof phyllotaxisЬy polar J. Traas,J.Frimi' and С. Kuhlеmеiеr.2003. auхintranspoft.Nаturе426:255_260' Salazar-Ciudad' I.,J. Jеrnvall'and S. A. Nеwn.rаn. 2003. Месhаnismsof pattеrn formationin dеvеlopmеntand еvolution.Deuеlopmепt1'30 2027-20з7. Sееlеy, T. D. 1995. Thе Wisdom of the Hiuе. СamЬridgе,МA: Нarvard Univеrsity Prеss.

З11

З12

Bеуoпd the Dаrluiniап Pаrаdigm Snow' М., and R. Snow. 1935. Ехpеrimеnts in phyllotaхis: Diagonal siits through dесussatе apiсes. Philosophicаl Trапsасtiс-lпsof thе Roуаl Soсietу of Loпdoп, SеriesB 225: 63_94. 1952. Minimum аrеa and lеaf dеtеrminаtion. Proceediпgs of the Roуаl Sociеtу of I,oпdoп, Sеriеs B 139: 545-.566. 5o16,R. V.' and B. С. Goodwin. 2000. Sigпs of Lifе: Hotu Сompleхitу Pеruаdеs Biologу. Nеw York: Basiс Books. Solё, R. V., o. \4iramontеs, and B. С. Goodwin. 199З. Osсillations and сhaos in ant soсiеtiеs.Jourпаl of Thеoreticаl Biologу 16I: 343_357. .WеЬstеr' G. С., and B. С. Goodwin. 1997. Form апd Trапsformаtioz. СаmЬridgе: СamЬridgе Univеrsity Prеss. -Гhе Wilkins, A. S. 2002. Еuolцtioп of Dеuеlopmепtаl Pаtbtuауs. Sundеrland, MA: Sinauеr Assсlсiагеs.

Philoso Though

Kim Stеre

Thе dеvеlopmеnt of еv l е с t ц a l a с h i е v е m е n t st l major сhallеngеs:how t i m е t o Ь е е х p l a i n е d 'l ganism and еnvironmе thеsе сhallеngеs. Thеrt Ьiota (еspесiallyif wе t thеrе arе сегtainlу mi Donoghuе 2004; Dаwl somеtimеs Ьrеathtakin1 1'996). Еvеn so, wе no\& divеrsity and adaptatiо of organismsin а popu diffеr, it drivеs diffеrе arisеs in thе population portant part of any org of diffеrеntiation. Diffе mеntal hеtеrogеnеity. Еvolutionary Ьiоlog1 сonсеrn ехplanations с to еxtinсtion Ьy a mеt .!Иas thеir ехtinсtion a m a l s ? S o m е с o n с е r nЬ r с r е а s е d m o r е o г | е s ss whеn it stаЬilizеd or еv tant has mass ехtinсtio nisms that gеnеratе ad that produсе vаriation? еvolutionary сhangе?F i t t h a t s u с h е l е m е n t s.

phvllotaхis:Diagonal slits through пs
Philosophyof ЕvolutionarУ Thought Kim Sterеlnу

Thе dеvеlopmеntof еvolutionary Ьiology sinсе 1858 is onе of thе grеat intеlIесtualaсhiеvеmеnts of sсiеnсе. Thе living world prеsеnts sсiеnсе with two major сhallеngеs:how is its immеnsе divеrsity aсross timе and at any givеn rimе to Ье ехplаinеd, and how is thе ехtraoгdinаry adaptivе fit Ьеtwееn organismand еnvironmеnt to Ье explainеd? Thеrе is no douЬting thе sсalе of thеsесhallеngеs. Thеrе arе no rеliaЬlе mеasurеs of thе divеrsity of today's Ьiota(еspесiаllyif wе takе into aссount thе divеrsity of miсrooгgаnisms),Ьuг thеrе arе сеrtainly millions of ехtant spесiеs of organisms (Сraсгaft and Donoghuе2004; Dawkins 2004). Likеwisе, thе adaptivеnеssof organisms is somеtimеsЬrеathtaking in its сomplexity and its еxquisitе prесision (Dawkins \996),Еven so' wе now havе at hand, in Ьroad outlinе, an ехplanation of Ьoth divеrsityаnd adаptation. In Ьrutal summary, sеlесtiondrivеs thе аdaptation of organismsin a population to thеir еnvironment,and Ьесаusееnvironmеnts diffеr, it drivеs diffеrеntiation too, taking advantagе of whatеvеr variation arisеsin thе population. Мorеovеr' sinсе thе Ьiologiсal еnvironmеnt is аn im. poгtantpaгt of any organism's world, thеrе is positivе fееdЬасk in thе proсеss of diffеrеntiation.Diffеrеntiation Ьrееds diffеrеntiation Ьy inсrеasing еnvironmеntalhеtегogеneity' Еvolutionary Ьiology has mаny important opеn quеstions. Somе of thеsе сollсеrn еxplanations of partiсular еvеnts. !Иеrе thе dinosаurs rеally drivеn to ехtinсtion by a mеtеor impасt, or Wеrе thеy on tlrеir way out anyway? Was thеir еxtinсtion a nесеssary prесondition for thе еvolution of thе mammals?Somе сonсеrn Ьroad pattеrns in thе еvolution of lifе' Нas divегsity inсгеasеdmorе or lеss srnoothly ovеr timе, or havе thеrе Ьееn long pеriods whеnit staЬilizеdor еvеn droppеd? Somе сonсеrn mесhanisms.Нow important has mаss еxtinсtion Ьееn in thе history of lifе? Arе thе sеlесtivеmесha_ nismsthat 8еnеratеadaptation importantly сonstrainеd Ьy thе mесhanisms thatproduсе variаtiоn? What arе thе rеlativе rolеs of sеlесtionand сhanсе in еvolutionaryсhаngе? How important arе sеlfishgenеtiс еlеmеnts,and how is it that suсh еlеmеnts arе usually nеutralizеd in огganisms' gеnotypеs? As t1.t

З 1 4 P h ilo sophу of Еu olиtionаrу Th o ught othеr essaуswili havе madе сiеar' thеsеarе important and diffiсuit quеstions' Ьut thеy sееm to Ье еmpiriсal quеstions. Sinсе philosоphегs do nоt сollесt data, what сould philosophеrs havе to say aЬout еvolutionary Ьiology thаt hеlps us undеrstand it? Нow сould irгlswеrirrgsuсlr quеstiot1sas thеsе Ье rеlеvant to philosophеrs'сoге proiесts? My prсliесt in this еssay is to ?lnswеr thеsе quеstions.I Ьеgin with thе rеlеvanсеof philosophy tO еvolutionaгyЬiology; I сorrсludеwith thе rеlеvanсеof еvolutionary biology to philosophy.

Fеrmеnt in Еvolutionary Biоlogy: Сonсеptual InnoсеnсеLost Тhе nеo-Daгwiniаn synthеsis w:rs dеvеlоpеd Ьy thе Ronald A. Fishеr ( 1 9 3 0 ) - J . B . S . H а l d a n е ( 1 9 3 1 ) _ S е w а lW l r i g l r t ( \ 9 З | , 1 9 3 2 ) t r i u m v i r a t еi n thе еarly 1930s and was сomplеtеd in Amеriсa Ьy Thеodosius DoЬzhansky ( 1 9 3 7 ) ,Е r n s t M a y r ( \ 9 4 2 ) , G е o r g е G . S i m p s o n ( 1 9 4 4 , 1 9 5 3 ) , a n d G . L е d yаrd StеЬbins (1950) and in Britain Ьy Е. B. Ford and his sсhooi (е.g.,Fishеr and Ford |947; Сain and Shеppard 1950, 1'952, 1954 Kеttlеwеll t955, 1956) Ьеforе, during, and aftеr \Х/orld.!ИarII. It bесamе thе rесеivеd viеw of еvolutionaгy Ьiology. lt was individualist, miсroеvolutionary,gradualist,and sеlесtiorrist.Thе synthеsisfoсusеd on individual orgаnisnrs:сompеtirivеin. tеraсtions takе plaсe Ьetwееnindividual organisms in loсal populаtions,not Ьеtwееn groups or spесiеs. Individual organisms arе morе or lеss fit; individuals prospеr or fаil. Thе synthеsiswas miсroеvolutionafy: thе lаrgеsсalе сhаngеs visiЬlе irr thе fossil rесord arе nothing Ьut thе aссumulаtionof small-sсaleсhangеs in loсal popul:rtions.Thе synthеsiswаs gradualist:еvolutionary сhangеs in loсal populations arе slow and inсrеmеntаl. Нorsеs lost thеir toеs and grеw thеiг tееth littlе Ьy littlе and ovеr long pеriods. And it was sеlесtiorrist.Сhanсе еvеnts piay :-tгoie in evolutionary сhangе. A potеntiаlly favoraЬlе mutation might simply just nоt happеn, or it might happеn to an organism that is fit Ьut unluсky. But aссording to thе synthеsis,natural sеlесtion is thе сlominant сatlsal faсtor that drivеs thе еvolutionary dynamiсs of populations. Thе synthеsislеft foгmidaЬlе tесhniсal proЬlеms unsolvеd, Ьut thе thеory of еvolution сonсеivеd this way sееmеd rеlativеly сonсеptually unproЬlеmatiс. This сonсеptual сlirrity was not сomplеtе. For ехаmplе' undеrstanding thе naturе of spесiеs sееmеd a pаrtiсuiarly prеssing proЬlеm, for thе vеry gradualisnr of thе synthеsis sееmеd to srr!]gеstthat thе appеaranсе of wеlldеfinеd spесiеs might Ье an illusion gеnеratеd Ьy thе lеngth of our lifе spans. Thеy sееm staЬlе and wеll dеfinеd only Ьесausеwе do not livе long еnough to seе linеagеsсhangе and diffеrеntiаtе.If wе had Ьееn around to sее thе anсеstral сat population gradually сhangе and diffеrеntiatе into its array of modеrn forms, pеrhaps wе would not think of lеopards, jaguars, panthеrs' and snow lеopards as distinсt, namеaЬlе units of naturе. Thеrе wеrе othеr issuеs too. for еxamplе, whеthеr еvolution is а gеnuinеly indеtеrministiсpro. сеss Ьесausеof thе rolе of сhanсе. not iust in thе sеnеration of variation Ьut

also in sеlесtiorr.Tlrе fi suссеssful, but thеy arе puzzlеs aЬout thе nаtu synthesis dеpеnс1еdon : yеt it was r-rnсlеarjust h Тhцs thе synthеsis o] Nonеthеlеss, thе сonсер morе intraсtaЬlе irr thе within Ьiologv. Thе mсl individualism, to thе idе ual organisms. For ехa (1976) aгguеd that sеlес .Wiilianrs аnd Dаr'vkins minеs its indir,idualism thе foгmidaЬlе wеapon pеlagiс vеrtеЬratеs-arс tion builds сoпrplеx si's thас form thе plаtform f tion must Ье linеagеsol tagеs bе prеsеrvеd-tha. Yеt organisnrs dtl not would shе Ье еvеn if I A сlonе of mе would nо and thеsе mаrks do not dеnt, I hаl,е itrst Ollе е}' thousands of gеnеs in п of thе gеnеs I сarry arе с сopiеd' that is, геpliсat agеs rеflесt thе diffеrin1 mаny gеnеrations and е short and thin. }.or thе l not itlst rеpliсators, thе f]uеrrсеthеiг prospесts Ьodiеs, thе vеlriсlеsin ц tory of lifе is tсl sее it as ing to sесurе thе rеsot Dawkins 1c76. 1982). Тhis linе of thought l to muсh сontеmporary g е n е s е I е с г i t l na g е n u i

Thеrе sееm ro llе аt lсаs gеnе sеlесtiorr havе nе сlе:rnеstrеsponsе wсlulс tinсt and supеrior altеr provе thеir rеpliсаtion Ьuild a wеll-adаptеd Ьс

P h iklsсlphу of Еuсllutitlпаrу Тh ought э importantand diffiсult quеstions' Sinсе philosophеrs do not сollесt Y aЬout еvolutionary Ьiology that ring suсh qllestiollsаs thеse Ьe rеlprojесt in this еssay is to answеr : of philosoph,vto еvolutionary billutionary Ьiology to philosophy.

Сonсеptual .lopеd Ьy thе Ronald A. Fishеr Tright(I9З1, 1932) triumviratе in nеriсaЬy Thеodosius DoЬzhansky mpson (\944,195З), and G. LеdB. Ford аnd his sсhool (е.g.,Fishеr i0, 1952, 1954; Kеttlеwеll 1955, r II. It Ьесamе thе rесеivеd viеw of gradualist' and miсroеvo1utiсlnaгy, i v i d u a l o г g e t r i s n r sс:o m p е t i t i v е i n lrganismsin loсal populations' not organisms arе morе or lеss fit; was miсrоеvolutionary:thе largе]е nothing Ьut thе irссumulation of .hе synthеsiswas gradualist: еvoluslow and inсrеmеntal.Horsеs lost е and ovеr long pеriods. And it was еvolutionaryсhange. A pоtеntially happеn, oг it r-niglrthappеn to an ding to thе synthеsis,natural sеlесгivеsthе еvolutiorrarydynamiсs of proЬlеmsunsolvеd, Ьut thе thеory .еlativеlyсonсеptually unproЬlеmplеtе.For еxamplе, undеrstanding гly prеssingproЬlеnr, for thе vеry ggеstthat thе irppеaranсе of wеllrtеd by thе lеngth of our lifе spans. есausеwе do not livе long еnough wе had Ьееn around to sее thе anand diffеrеntiatе into its array of ink of lеopards, jaguars, panthеrs' nits оf naturе.Theге Wеrе othеr isi s a g е n u i n е l yi n d е t е r m i n i s t i сp r o t in thе gеnеrationсlf variation Ьut

.Гhе also in sеlесtion. fittеr organisms in a population arе morе likеly to Ье suссеssful,Ьut thеy аrе not сеrtain to Ье morе suссеssful.Thus thсrе ',vеrе puzzlеsaЬout thе ll:lturе of fitnеss аnd its сausurlrсllе in еvolutiсln. fсlr thе synthеsisrlеpеnсlеdon а distinсtion Ьеtrд,ееrr асtlrаl аnd ехpeсtеd fitnеss,and yеtit Was unсlеar just how this distinсtlOnWas to Ье drаwn (SoЬег 1984). Thus thе synthеsisof еvolutiсlnarythеory did posе сonсеptual qtlеstions. Nonеthеlеss,thе сonсеptualgеogrаphy сlf еvolutionary Ьiology Ьесatlrеmuсh morе intraсtaЬlе in thе 1970s and 1980s as thе synthеsis сamе undеr firе within Ьiology. Thе most systеmatiссhаllеngеto thе synthеsishas bееrrto its individualism,to thе idеa thаt the targеtsof sеlесtionarе, ехсlusivеly' inс1ividual organisms. For еx:rmplе,G. С. Williапls (|966| and Riсhагd Dirr'"'kirrs (1976)arguеd сhаt sеlесtiondoеs not rеаllу aсt оrr iгrdividualorgenisr-ns аt all. \ililliams аnd Dawkins сlaimеd that tlrе gradualisnr of thе sуnthеsis rtndегminеs its individrrаlism. Сomplех Ьiologiсаl adaptations-sеllsoгy systеms' thе formidaЬlе wеаpons of prеdatсlrs,thе powеr аnd strеanrliningof grеat pеlagiсvеrtеЬratеs-arе Ьuilt inсrеmеntally' оnе small stеp at a timе. Sеlесtion Ьuilds сomplеx systеmsсumulativеly Ьv prеsеrvingsmаll improvеmеnts that form thе platforrn for furthеr small improvеmеnts. So thе targеts of sеlесtion must Ье linеаgеsof nеar-pеrfесtсopiеs-fсlr only thus сan smаll ас1vlrntаgеsЬе prеsеrvеd-thilt pеrsistthrсlughmany сvсlеs tform linеagеs'Мl' daughtеr is not i1сoP}.tlf mе, nor would shе bе еvеl'l if I wеrе аn asехuаl сrеаturе rеproduсing [rу сIoning. A сlonе of mе wсlrrldnot Ье a nеar-pеrfесtс()py' for lifе's aссidеnts пrark mе, and thеsеmarks do not rеappеar on a сlonе' As a rеsult of a сhildhood aссidеnt,I havе just сlnе еyе: a сlсlnеwould havе two. In сontrast' though' mаny thousandsof gеnеs irr my daughtеr arе сopiеs of gеnеs in mе; likеwisе' rтost of thе gеnеsI сarry аrе сopiеs of parеrrtalgеnеs.Gеnеs, unlikе orgаnisnls,.trе сopiеd,thаt is, rеpIiсatесl,and thеy do forrn pеrsisting linеagеs.Thеsе lirrеagеsrеflесtthе diffеring suссеssсlf gепеs:s()rтtеarе dееp аnсi Ьtlshy. lasting manygеnегationsirnd ехisting in man'vсo1rjg5in еaсh gеnеratiotl.othеrs arе shortand thin. Foг tЬе most pаrt' thеsеdiffЪrеnсеsarе no aссidеnt:gеllеs аrе not just rеpliсatoгs,thеy arе aсtivе rеpliсators. Thеir own сh:rraсtеristiсsinfluеnсеthеir prospесts for repliсation, normally through thеir influеrrсесln bodiеs,thе vеhiсlеs in whiсh thеy ridе. Thе гight Wаy to think aЬout tlrе history оf lifе is to sее it :ls a giant struggle Ьеtwееп linеagеsсlf gеnеs,еaсh tryi n g t o s е с u r е t h е r е s o u r с е sn е е d е d f t l r r е p l i с a t i o n ( W i l l i a m s 1 9 6 6 , | 9 9 2 1 D а w k i n s| 9 7 6 . | 9 8 2 \ . Тhis linе of thorrghthas гaisеd vег,vdiffiсu|t issuеs indееd that аrе сеntral to muсh сontеnrPorarуphilosophy of еvolutionary Ьiology. In whаt sеnsеis gеnеsеlесtiсlna gеnuinе altеrnativе ttl thе individualism of thе s1'nthеsis? Thеrеsееmto Ье at lеast thrее answеrs to this quеsti()n'and thе dеfеnсlеrsof gеnе sеlесtion hаvе nеvеr rеally piсkеd thеir rеspоnsе. Тhе simplеsr and сlеаnеstrеsponsеwtltrld Ье to insist thаt gеnе sеlесtion is an еmpiriсаllr' distinсtand supеrior altеrrrаtivеto individualism. Thor-rghgеnеs normally irrrprovеthеir rеpliсation prospесts Ьy hеlping tlrе сlthег gеnеs in an епrЬryo Ьuilda wеil-аdaptеd Ьody that will сагrу thеm all intсl thе nехt Е.елеr.ltion'

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P h ilo sophу of Еu olutioпаrу Т h ough t thеy do not always rеpliсatе so сoopеrativеly.For ехamplе, somе gеnеsсan gеt to thе nеxt gеnеration only if thеy arе in an organism of thе right sеx. Thе gеnеs in thе mitoсhondriа in my spеrm сеlls arе doomеd, for mitoсhondrial gеnеsdеsсеndonly in thе fеmale linе. Мy darrghtег'smitoсhondriаl gеnеsаrе all сopiеs of gеnеsin hеr mothеr. In many сirсumstаnсеsorganisms arе fittеst if thе sех ratio of thеir offspring is 50-50 or thеrеabouts. But gеnеs that dеsсеnd via only onе sеx havе no intеrеstin thе Ьody of whiсh thеy arе a part having offspring of thе othеr sеx, and thеsе gеnеs arе undеr sеlесtion to distort thе sеx ratio in thеir favor, еvеn though this is maladaptivе for thе organism of whiсh thеy arе a part. Many suсh sеx-ratio distortеrs arе known (Burt and Trivеrs 2005). Sех-ratio gеnеs and othеr so-сallеd gеnеtiс outlaws prompt thе following rеsponsе: gеnе sеlесtion is prеdiсtiuеlу differепt from thе synthеsis. Gеnе sеlесtion prеdiсts that phеnotypеs that ехprеss thе fittеst gеnеs will Ьесomе morе сommon ovеr timе; thе synthеsisprеdiсts that phе. notypеs thаt сhаraсtеrizе thе fittеst organisms Ьесomе more сommon ovеr timе. Although thеsе prеdiсtions ovеrlap suЬstantivеly, thеy arе not idеntiсal. Мany havе rеspondеd Ьy aссеpting that whеn gеnеs arе outlaws' Wе should indееd sее thеm as targеts of sеlесtion,Ьut thеy takе thеsе to Ье еxсеptional сasеs that do not undеrminе thе gеnеral validity of individualism. Sеlесtion doеs асt on gеnеs' Ьut only in vеry spесial сonditions. So a sесond way of dеfеnding gеnе sеlесtionis to aссеpt that it is, fсrrthе most part' prе. diсtivеly idеntiсal to thе synthеsis, Ьut that it appеals to distinсt undеrlying сausal struсturеs. Twсl thеoriеs сan lеad to thе samе prеdiсtions aЬout oЬsеrvaЬlеoutсomеs еvеn whеn thеy posit distinсt undеrlying сausаl proсеssеs. Еlliott SoЬеr and David \7ilson, in thеir сhallеngе to thе synthеsis, aссеpt that individualist viеws of thе еvolution of сoopеration сan makе thе right prеdiсtions, Ьut thеy arguе that thеsе misidentify its сausal Ьasis. Сoopеra. tion, thеy say, еvolvеs only whеn and Ьесausесoopеrativе aсts еnhаnсе thе fitnеss of thе groups that сontain сoopеrativе agеnts (SoЬеr and Wilson 1998). Likеwisе, with rеgard to gеnе sеlесtion, fit gеnеs arе fit Ьесausе thеy асt on thеir еnvironmеnt in ways that еnhanсе thеir proЬaЬility of rеpliсation. Thе usual mеthod gеnеshavе of еnhanсing thеir rеpliсation prospесtsis by tеaming up with othеr gеnеs to produсе vеhiсlеs, whiсh in turn rеproduсе' rеpliсating thе gеnеsthеy host. Most of thеsеvеhiсlеsarе organisms,Ьut pеrhaps they сan Ье hivеs, nеsts, and symЬiotiс allianсеs too. Fit gеnеs makе wеll-adaptеd vеhiсlеs, whiсh in turn rеpliсatе thеir Ьuildеrs. Thе faсt that gеnеs typiсally adopt this indirесt Stratеgy of rеpliсation Ьrings thе prеdiсtions of gеnе sеlесtion into linе with thosе of thе synthеsis,Ьut thе various piсturеs of thе сausal struсturе of sеlесtion (gеnе' individual organism) rеmain distinсt. A third linе is to аrguе that gеnе sеlесtionhаs hеuristiс advantagеsovеr thе synthеsis.Striсtly spеaking,it is rrot a diffеrеntviеw of thе сausal struсturеo{ еvolutionary proсеss;instеad, it еnaЬlеs us to sее possiЬilitiеsand proЬlеms that thе synthеsisсonсеals. Dawkins took this linе in Thе Ехteпded Phепotуpe (7982), his most important dеfеnsеof gеnе sеlесtion.Hе gavе many еxamplеs of еvolutionary phеnomеnа that arе simply morе saliеnt whеn wе

think of thе Ьiologiсal u O n е s u с h p h е n o m е n < li linеagеs mostly rеpliсatе сlеs? Givеn tЬаt thеy do. of organisms, in parttс singlе-сеllеd stаgе? Dаw сyсlеs, and, indееd, s<;m is possiЬlе to formulatе t сharaсtеristiс llfе сyсlе fr sеlесtion makеs that qu еxamplеs of thе advanta Thе issuе of gеnе sеlе pесt of thе dеЬatе aЬout losophy of еvolutionary that сoopеration is сеntl сal systеms arе сomposе to Ьеhavе in ways thаt quеstion, thеn, is how n tion on thе individuals tl David Wilson' StеphеnJ aсt on individuals, Ьut t} spесiеs (SoЬеr and \rVils vidualism of thе synthеs gгadualism. Aссоrding t lifе arе just aggrеgation sеrvе еvolution in асtto raЬbit immunе systеmsl Ьесoming lаrgеr in dry s all thе mесhаnisms of е that arе сhanging in sm and lots of timе to aссu tегns of thе fossil rесord In a famous 1972 ess fossil rесord doеs not st thеy maintаinеd that thе trаpolationism to Ье tru spесiеs do nсlt сhangе spесiеs сomе into ехistе thеy split into daughtеr doеs dеsсriЬе thе typlсa r o | | | 9 9 l ) . B u r i | :Е l d r е еxtrapolationism. If еvс сhangеs in loсal popula than long pегiods witho is truе that thеrе arе lс сasеs; poptrlations сan

Philosoph1'of Еuсllutioпаrу Thought еly. For еxamplе, somе gеnеs сan r an сlrganismof tlrе right sеx. Thе ls arе doomеd, foг mitoсhondrial аtlgЬtеr'smitoсhondrial gеnеs are lirсltmstanсеs organisms arе fittеst эг tlrеrеabouts.But gеnеs that dеthе Ьod1,of whiсh thеy arе a part е g'еnеsarе undеr sеlесtion to disgЬ this is maladaptivе for thе orсh sех-ratio distortеrs arе known nd othеr so-сallеdgеnеtiс outlaws tion is prеdiсtiuеlу diffеrent from pЬеnotypеsthat ехprеss thе fittеst е; thе synthеsisprеdiсts that phеisms Ьесomе morе сommon ovеr thеy arе not idеntiсal. rЬstantivеly, rat Whеn gеnеs arе outlaws' wе 'iоn, Ьut thеу tаkе thеsе tо Ье ехgеnеralvalidity of individualisrn. r 1 s p с с i a |с o n d i t i o n s .S o а s е с o n d )t that it is, for thе most part' prеrt it аppеalsto distirrсtundеrlying o tlrе sаmе prеdiсtions aЬout oЬstinсtundеrlyingсausal proсеSsеs. с l r а | I е n grеo t h е s y r l t h е s i s 'a с с е p t lf сoopеrationсan makе thе right idеntify its сausal basis. Сoopеraаusе сoopеrаtivеaсts еnhanсе thе :rаtivе tlgеnts (SoЬеr and Wilsоn :tion, fit gеnеs arе fit Ьесausе thеy hаnсе thеir proЬability of rеpliсan с i n gt h с i r r е p l i с а r i o np г o s p е с t si s vеl-riсlеs, whiсh in turn rеproduсе, :sеvеhiсlеsarе оrgatrisms,Ьut pеrotiс allianсеstoo. Fit gеnеs mаkе iсatе thеir Ьuildеrs' Thе faсt that y of rеpliсation Ьrings thе prеdiсе of thе synthеsis,Ьut thе various эn (gеnе,individual organism) rе_ n has hеuristiсadvantagеsovеr thе rеntviеW of thе сausal struсtцre of s to sееpossiЬilitiеsand problеms ' this linе in Thе Ехteпded PbeпoHе gavе many ехf gеnеsеlесti
tlrirrko{ thе Ьiolоgiсzrltlnivеrsеas аn еnsеmЬlе of сompеting gеnе linеаgеs. onе suсh phеnomеnon is thе еvolr-rtionof thе organism itsеlf. Why do gеnе linеagеsmostly rеpliсatе indirесtl,v,via thе сoopеrаtivе сonstruсtion of vеhiсlеs?Givеn that thеy do' why do vеhiсles hаvе thе distinсtivе сhaгaсtеristiсs o[ organisms, in partiсular, a lifе сyсlе that involvеs rеproduсtiotr via a s i n g l е - с е l l е sdt а g е ?D a w k i n s p o i n t s O u t t h a t i t i s е a s 1 ,t o i m a g i n е o t h е r l i f е сyсlеs,аlld, indееd, sonrе of thеsе аltеrnаtivеsirrе геal, rhough unсommon. It is possiЬlеtсl foглrulatеthis quеstion аЬout thе oгigin of organisms and thеir сharaсtеristiсlifе сyсlе from withirl thе pеrspесtivеof thе synthеsis,Ьut gеnе sеlесtionmakеs that quеstion inеsсapaЬlе, and Dawkins givеs marry othеr еxamplеsof thе аdvаntagеsof thе gеnе-sеlесtionpеrspесtivе. Tlrе issuе of gепе sеlесtionand its rеlation to individuаlism is iust Onе aspесtof thе dеЬаtе aЬout thе units of sеlесtionthat is now сеntral to thе philosophy of evolutionary Ьiology. F,volutionary Ьiologists havе сonrе to sее that ссloperationis сеntral to thе еvolution of соmplеxity. Сomplех biologiсаl systеmsarе сonlposеd of individuals, and thеsе :rrеoftеn undеr sеlесtion to Ьеhavеin wаys tlrilt undеrminе thе intеgration of thе сollесtivе. A kеy quеstiol1'thеn, is lrow nеw lеvеls tlf oгganizatiolrеvolvе in thе faсе of sеleс_ tion on thе individuals thаt makе tlrеm up to go thеir own way. Еlliott SoЬеr' David lfilson, StеphеnJay Gould, and othеrs havе agrееdthat sеlесtiondoеs aсt on individuals' Ьut thеy havе arguеd that it aсts as wеll on groups and on spесiеs(SoЬеrand !Иilson 1998; GoLrld 2.002).Furthеrmorе' iust as tlrе individuаlismof thе syntlrеsishas гаisеd diffiсult соnсеptш:rlissuеs,so too hаs its gradualism.Aссording to thе syntlrеsis,laгgе-sсalеpаttеrns in thе history of lifе arе just aggrеgationsсlf small-sсalесhangеs. Biologists сan aсtually obsеrvееvolution in aсtion in loсal populations: thеy сan oЬsеrvе сhangеs in rаЬЬitimmunе systеmsas rаЬЬits arе ехposеd to a nеw virus, or finсh Ьеaks bесonringlargег in drv sеasons.Aссording to thе graduzrlismof thе syr-rthеsis, all thе пrесhanisnrstlf еvolutionar1.сhangе arе аrtrvork in loсal populаtions !Ие just nееd spaсе tЬat arе сhanging in small Ways ovеr a fеw gеnеrаrtiсlns. and lots of timе to aссumulatе thе rеsults of thеsе mесhanisms into thе pattеrnsof thе fossil rесord. In a famous 1972 essaуNilеs Еldrесlgeand Stеphеn Gould arguеd tlrаt thе ..ехtrirpolationist'' fossilrесord doеs not sLlpport this рiсtr.trе'In partiсulаr, thеymaintainеdthirt thе trее of lifе doеs not сhangе еnough ovеr tiпlе for ехtrapolаtionismto Ье truе (Еldrеdgеand Gould 197z|. Thеy arguеd thаt most spесiеsdo not сhangе signifiсаntly ovеr most of thеir lifе spans. Instеad, spесiеsсomе into еxistеnсеrеlativеl,vquiсkly and tlrеn do not сhаngе until thе1'splitinto dаughtеr spесiеsor Ьесomе еxtinсt. Tlrе ехtеnt to whiсh this doеsdеsсriЬеtlrе typiсаl lifе histtlr,vof a spесiеsis still t>pеnto dеЬаtе (Сarrolr|1997|.But if Еldrеdgе and Gould arе right, tlrеir piсturе doеs сhallеngе ехtrapolationisrn.If еvolutionary pilttеrns аrе nothing Ьut thе aggrеgatе of сhangеsin loсаl populations, wе w
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З 1 8 Phibsopbу of Еuolиtionаrу Тhought than adapting in plaсе; adaptations сan Ье Ьеhavioral rathеr than morphologiсal and hеnсе саn Ье invisiЬlе to us. Еvеn so, if thе fossil rесord is nothing Ьut population-lеvеl еvolution summеd ovеr largе quantitiеs of spaсе and timе, wе would not еxpесt stаsis trl Ье its dominаnt pаttеrn (Еldrеdgе 199.5; Gould 2002). Gould has dеvеlopеd a nrorе radiсal сritiquе of еxtrapolationism that rеjесts Ьoth its individuаlism and its gradualism. In a сlassiс artiсlе Lеwonтin dеfinеd thе idеa of a Dаrшiпiап populаtioи: a populatiоn of individuals that diffеr onе from anothеr and еxpеriеnсе diffеrеntial rеproduсtivе suссеss, and in whiсh dеsсеndants inhеrit thеir anсеstors' distinсtivе traits. Suсh populations еvolvе undеr natural sеlесtion (Lеwontin 1970). Gould arguеd that spесiеs groups form Darwinian populations (Gould 2002; Gould аnd LIoуd 1999). Spесiеs havе dеtеrminatе origins and еndpoints. Dаughtеr spесiеsrеsеmЬlе thеir anсеstors:rесonstruсtingphylogеny would Ьe impossiЬlе if this wеrе not so. Spесiеs arе diffеrеntially suссеssful.\Within a rеgional Ьiota somе spесiеs linеagеs will diffеrеntiatе riсhly, radiating into many niсhеs' whеrеas othеrs will rеmain rеstriсtеd in numЬеrs and есоlogiсal pеnеtration. Gould doеs not еХpесt spесiеs-lеvеlsеlесtionto ехplain thе adaptations of organisms, for ехamplе, thеir pеrсеptual systеms, Ьut hе thinks that sеlесtion will ехplain сharaсtеristiсsof spесiеsthеmsеlvеs:suсh propеrtiеs аs gеnеtiс variation, population struсture' аnd gеographiс rangе arе visiЬlе to spесiеs-lеvеlsеlесtion and hеnсе саn Ье thе targеt of spесiеslеvеl sеlесtion. Gould's idеas aЬout spесiеssеlесtionfaсе sеrious proЬlеms. For onе thing' thеrе arе no сonvinсing сasе studiеs of spесiеssеlесtionin aсtion. Morеovеr, thеrе arе sеrious thеorеtiсal сhallеngеs to his idеas. It is Ьy no mеans сlеar that thе inhеritanсе сondition on Darwinian populations is satisfiеd.It is truе that thе organisms in a daughtеr spесiеs rеsеmЬlеthе organisms in thе parental spесiеs.But thе spесiеs-lеvеlpropеrtiеs of thе dаughtеr-its distribution and population struсturе-may not rеsеmЬlr thosе of its parеnt at all. Furthеrmorе, in thinking of spесiеs suссеssand failuге, wе mаy not Ье ablе to distinguish drift from sеlесtion.Thе suссеssor failurе of indiuiduаl orgаnisms is not always thе rеsult of sеlесtion.Somе mortality is thе rеsult of unhappy aссidеnt rathеr than ill dеsign. Somе оrganisms arе fесund Ьy luсk, dеspitе thеir dеsign flaws. Hеnсе rеalizеd fitnеssdiffеrs frorrr ехpесtеd fitnеss.Suссеssduе to systеmatiсfеaturеsof thе population's еnvironmеntis suссеssin virtuе of ехpeсtеd fitnеss,as whеn a swallow dodgеs a hawk. Suссеss duе to frеak aссidеnts-Ьеing Ьlown Ьy a storm to а frеightеr that is hеading in thе right dirесtion-is drift. But thе distinсtion Ьеtwееn ехpесtеd and frеak сausеs of mortality dеpеnds on thе ехistеnсе of a population of еvеnts that is largе еnough for thеrе to Ье pilttеrns in thosе еvеnts.Howеvеr, spесiеs population sizеs arе so small and сyсlеs of sеlесtiоn аrе sо fеw that Wе may not Ье aЬlе to draw thе distinсtitln Ьеtwееnsеlесtivеand aссidеntal mortality. I hopе thаt thеsе ехamplеs havе Ьеgun to еxplain thе rеlеvanсесlf philosophy to еvolutionary thеoгy. It is rеlеvant Ьесаusе tlrе еmpiriсal issuеs in-

I volvеd in rеthinking tual issuеs. Thе nехt tant proЬlеm aЬout t biology.

Еvolution within

In thе past dесadе oI intеgration of еvoluti multifaсеtеd. It arisе сonnесts еvеnts in loс spесiеs. It arisеs in dt playеd littlе rolе in l twеntiеth сеntury. As tal Ьiology rеmains hl arе Ьoth еvolvеd anir logiсal sсiеnсеs and t thеy nееd somеhоw about human agеnсу I shall Ьriеfly introdu' .sИhat is а gеnе? Tl twееn thе сlassiсal gс and molесular biolog siсal gеnе of thе frui еffесt and was trans quеnсеs with Ьoth о DNA sеquеnсе-hor,r sеnsitivе to the loсal off and сan еvеn Ье aЬsеnсе of rеprеssor rеgions nееd not Ье; not Ье passеd on whс Nеumann-Held 199\ straсt away from thi and instеad think of 5 itanсе: unlеss suссеs that makе thеm suсс adaptivеly ovеr timе i flow of aссuratеly сo1 tionary Ьiologists oft formation aЬout thе gеnеs is еditеd Ьy nat gеnеfаtion and unsui wе сan think of thе 1 aЬoцt organisms an<

P h iloso1lbуof Еuolutioпаrу Th ought е bеhaviorrrlrathеr than mсlrpho:n so, if thе fossil rесord is nothing vеr lаrgе qllantitiеs of spaсе and c o m i n а n tp а t t е r n( Е l d г е d g е1 9 9 5 ; tiquе of ехtrapolationism that rе,lism.In a сlassiс artiсlе Lеwontin и: a population of individuals that diffеrеntiаl rеproduсtivе sLlссеss' distinсtivе tгaits. Suсh l111сеstoгs' n (Lеworrtirr1970). Gorrld arguеd ш l а t i o n s( G o u l d 2 0 0 2 ; G o u l d a n d origins аnd еndpoints. Dаughtеr would Ье irnposlсting phyl
volvеdin rеthinking thе synthеsisarе not сlеarly sepaгatеdfrom thе сonсеptual issuеs.Thе nеxt sесtion makes thе samе point in disсussing onе important proЬlеm aЬout thе rеlationship of еvolutionary thеory to dеvеlopmеntal biology.

Еvolution within thе Lifе Sсiеnсеs In thе past dесadе or so a furthеr issuе has Ьесomе inсrеasingly saliеnt: thе intеgrationof еvolutionаry Ьiology with the rеst of Ьiology. Thе prоЬlеm is multifaсеtеd.It аrisеs with есology in idеntifying thе transmission Ьеlt thаt сonnесtsеvеnts in loсal populations with thе еvolution and diffеrеntiation of spесiеs.It arisеs in dеvеlopmеntal Ьiology, a domаin of thе lifе sсiеnсеs that plаyеd littlе rolе in thе сonstruсtion of thе synthеsis in thе nriddlе of thе twеntiеthсеntury. As a сonsеquеnсе'thе naturе of еvolutionary devеiopmеntal biology rеmains highly сontеstеd. It arises for humаn Ьiology, for humаns arе Ьoth еvolvеd animals and еnсulturеd agеnts: thе pеrspесtivе of thе Ьiologiсal sсiеnсеs and thе pеrspесtivе of thе soсiаl sсiеnсеs arе both valid, and thеy nееd somеhow to Ье part of a singlе unifiеd framеwork for thinking aЬout human aЕ.еnсy(Stеrеlny 2003). It аrisеs for molесular Ьiology, and I shall Ьriеfly introduсе onе aspесt of this сasе. !0hat is a gеnе? This quеstion is сhallеnging Ьесausе thе rеlationship Ьеtwееnthе сlassiсаl gеnеtiсsof Меndеl and his twеntiеth-сеntury suссеssors аnd molесular Ьiology has turnеd out to Ье vеry сomplех indееd. Thе сlassiсal gеnе of thе fruit-fly ехpеrimеnts Ьoth lrad a wеll-dеfinеd phеnotypiс еffесtand was transmittеd as a singlе unit. Thеrе may bе no DNA sеquеnсеswith Ьoth of thosе propеrtiеs' for thе dеvеlopmеntal import of a DNA sеquenсе-how and whеn it is transсriЬеd-has turnеd out to Ье vеry sеnsitivеto thе loсal gеnеtiс еnvironmеnt. Gеnеs сan Ье switсhed оn and off аnd сan еvеn Ье rеad in diffеrеnt ways, dеpеnding on thе prеsеnсе or aЬsеnсеof rеprеssors and promotеrs еlsеwhеrе in thе gеnomе. Sinсе thеsе rеgionsnееd not Ье adjaсеnt to thе DNA strеtсh thеy influеnсе' thеy mау not Ье passеd on whеn that DNA sеquеnсеitsеlf is rеpliсatеd (Griffiths and Nеumann-HеLd 19991 Griffiths 2002). Еvolutionary Ьiologists oftеn aЬstraсtaway frorn thеse molесulаr dеtails of gеnе сopying and еxprеssion andinsteadthink of gеnеs as infoгmation Ьеarеrs.Еvolution requirеs inhеritanсе:unlеss sцссеssful organisms arе apt to transmit thе сharaсtеristiсs thаt mаkе thеm sцссеssful to thеir offspring' a population сannot сhаngе adaptivеlyovеr timе in rеsponsе to sеlесtion.Inhеritanсе is mеdiatеd Ьy thе flowof aссuratеly сopiеd gеnеs from onе gеnеration to thе nехt' and еvolut i o n a r yЬ i o l o g i s t so f t е n t h i n k o f t h е s еg е n е sа s i n s t г u с t i o n s ,a s с а r r y i n g i n formаtionaЬout thе organism of whiсh thеy arе a part. Sinсе thе flow of gеnеsis еditеd by natural sеlесtion,with stritaЬlеonеs making it tо thе nеxt gеnеrationand unsuitaЬlе onеs bеing dеlеtеd by thе dеаth of thеir сarriегs, Wесan think of thе population gеnе pool аs сarrying information dirесtly about orяanisms аnd indirесtly aЬout thе еnvironmеnts in whiсh thosе

З19

З20

Pbilosophу of Еuolиtioпаrу Thought oгgаnisms havе livеd and rеproduсеd. Thе suссеss of somе gеnеs and thе failurе of othеrs is a signal аЬout thе natrrrе of thosе еnvironmеnts (.!7illiams 19921 Мaуnard Smith 2000a). This piсturе of сross-genеrati
Why Biоlogy Мatt

I havе Ьееn disсussingс is rеlеvant to thеsесhal that would sеttlе (for е twееn maсro- and miсrt еvolution. onе rolе for spесify ехасtIy what th is rеlеvant to еvсllutior dееd, it is rеlеvant in at ехplanаtory agеnda for рhy. (2) It providеs а с must fеspond. (З) It pr. adapt for its own proЬlt vеry diffеrеnt from thе r Ь a s е d . I s h a l l d i s с u s s( 1 on (4) in thе following s 1. Lеt mе Ьеgin witl twеntiеth-сеntury philos part of thе natural woгld proЬlеm: to What еxtеn and our world соmpati pIех еvolvеd Ьioсhеmiс Wе arе sеlf-awarе; dеlit tional; and awarе of mо Pеrhаps this piсturе is t us as gеnе-rеpliсаting rn сhoiсе' rationality, or rт С o m p e t i Ь il i s t n а r u r a I i s thеy pеrhaps rеquirе sor has dеfеndеd thе idеа tl сhoiсеs (Dеnnеtt200З) еxamplе, in еthiсs Мiсh; arguеd that thе natural l truth'' is an illusion. Thе Мoral Ьеliеf systеms еxr down thе dеstruсtivе pu nothing to do with it. Hu Ье anсеstors;сlthеrsdid l p h y Ь y с г а n k i n gu p r h еt t sеlf-portrait. 2. Еvolutionary Ьiolo1 plеs. Мuсh philosophy l most always thought е philosophy, just as thеy

P hilosophуtf Еuolutioпаrу Тhought hе srtссеssof somе gеrrеsand the "е
Why Biology Mattеrs to Philosophy I havеЬееn disсussingсhallеngеsto thе nеo-Darwiniаn synthеsis.Philosophy is rеlеvantto thеsесhallеngеs,for thеге is no singlе е-хpеrimеntоr prеdiсtion thаt lvould sеttlе (fсlr ехаmplе) thе fatе of Gould's viеw, of thе rеlations Ьеtwееnmасro- and nriсroеvolr.rtirln or сlf Dаrvkins's viеw of tlre rtllе of gеnеs in еvolution.onе rolе for philosoplrу is to Ьring thеsе viеws into sharp foсus: to spесifyехaсtly what they сlаim aЬout lifе and its histсlry.Just as philosophy is rеlеvantto еvolutionаry thеory' tlrat thеory is rеlеvant to philosophy. Indееd,it is rеlеvant iI-rаrtlеast four wavs: (1) Еvolutionilry Ьiology 1rеlpssеt thе ехplanatoryagеnda for tlnе majoг tтrovеmеntof twеl-ltiеth-сеnturyphiloso. phy. (2) It providеs а сruсial sеt оf еxamplеs tсl wlriсh philosophiсаl thеoгy nrustrеspond. (З) It provides an important sеt of tools that philosсlphy сan adaptfor its own proЬlеms. (4) It is аn ехеmplar of sсiеnсеin aсtion, Ьut it is vеrydiffеrеntfrom thе usual modеls on whiсh philosophy of sсiеnсеhirs Ьееn Ь a s е dI. s h a l l d i s с u s s( 1 ) , ( 2 ) ,a n d ( 3 ) i n t h i s s е с t i ( ) nа n с l s p е n d t h е m o s t т i m е on (4) in thе following sесtion. l. Lеt mе Ьеgirr with thе ехplаrrаtory agеndа. onе major movеmеnt of twеntiеth-сеntury philosophy has Ьееn naturalism: sееing humans аs wholly partof thе natural world. In tuгn, naturalismgеnеratеsa diffiсult philosophiсal proЬlеm:tо what ехtеnt is our ordinаry' сommonsеnsеpiсturе of or.rrsеlvеs and our world сompatiЬIеwith thе fасt that wе arе ntrtЬingmorе thаn сOmplех еvolvеd Ьioсhеmiсalmaсhirrеs?С
J21

З22 Р h iloso1ll ll, of Еu ol u tiсlпаrу T h ougbt сountеrfaсtual сasеs' and so it is appropriatе to ссlnsidегсountеrfaсtualsсеnаrios. Bцс thеrе arе good rеasons for morе sеriсlus :rttеntioll to геal plrеnomеna as wеll. First, thought еxpеrimеnts arе oftеn undеrdеsсriЬеd.Thеy аЬstraсt аway from thе riсh dеtail of rеal саsеs. Morеovеr' marry of thеsе thought ехpеrimеnts lеaсl to а сl:rsh of irrtr.ritions, partly bесausе intuitivе judgmеnt is sеnsitivе to just how сlnе dеsсriЬеs thе thought е-хpеrimеnts. onе sеt of thеsе imаrgеdsсеnarios involvеs Stаr Тrеh-stylе tеlеtransportеIs and sееnrsto sh
Sо thosе whо thirrk t naturаl woгld nееd to е ship Ьеtwееn а syпrЬоl ; and his еllvironment п n r i n d i s а s 1 ' r l i Ь oflo r s p i to this quеstion. An intr targеts in thе world. Pе dеrs. This is a nаttrгаls grams. Howеvег, almos to Ье oЬjесtivеly sin-rilа aРРеaranсе of rеal siпri atеd Ьy thе way hшman othеr thor'rghtsmuсh m somе mеntаl statеs аге .What not imagеlikе. rsl was thе foundеr оf logiс So thе rеlation Ьеtlvе ship. But pеrhaps it is a othеrs. Think in partrс r l - r е г еi s а r е I i а Ь l ег е I а t оnе's tank. That is whа So an intеrnal statеof Pt thеге Ьеing а spidег in h г i o n s h i p l r е t w е е nl t n i n t fеaturе of thе еnvironmс will prсlЬably not dсl еitl pегсеption. Lots of my winе aЬout. But thе сruI possiЬlе for us еvеr ttl г araсhnophoЬiс, аnd hrs will oftеn think ..Spidе sеnting his еnvirtsvmL еgory of spidеr look-ali forth). And sinсе Pеtеr аlikеs,hе has madе no п David Papinеau аnd I thе rеlationship Ьеtwееn funсtion. Thе Ьiologiсal с o n с е al t t t е nг . Т h o s с .е g g t o r s t O s p r l t a g а i n s tг у p i to lrаtсh than thosе tnа makеs it truе to sа1ythat On any partiсular еgg t

Philosopbу of Еuolutioпаrу Тhought )rlatеtO сonsidеr сountеrfaсtuаl sсе_ morе sеrious аttеntion to геal phе. еnts arе oftеn undеrdеsсriЬеd. Thеy 'еal сasеs.Мorеovеr, many of thеsе г i n t t t i t i < l tpl sа.r t l y b е с a u s еi n t u i t i v е d е s с r i Ь е tsh е t h o u g h г е x p е г i m е n t s . lvеs S/.rr Тr e k-stу|e tеlеtransportеrs ruitуis not thе samе as thе сontinut is еаsy to tеll thеsе storiеS so that ,сtuallytravеling whilе lеaving onе's kе tЬеп-rsееm likе killing maсhinеs tn impostor. This sеnsitivity to thе dеtailsmattеr. Vаry thе sеtting, and in thе dеtails' nothing Ьut thе rеal rot fully сonsidеrеd thе rаr-rgеof aсеnnеtt'swork is important in this rеLsallowеd philоsophеrs to rеpеatеdly a сontinuum Ьy rrеglесtingthе rangе rg aЬоut rationаl аgеnсy' philosointеntional agеnсy with mеrеly mеlаti
So thosе who think that humans arе Ьoth thinking Ьеings and part of thе naturalwсlrld nееd to ехplirin thе nаturе of mеrrtаlsymbols аnd thе rеlationshipЬеtwееna syrnЬol and its targеt.Y/hat faсts аЬout Pеtеr'sЬrain, his lifе' and his еnvirоnmеnt mаkе it truе that a partiсulаr intеrnal fеaturе of his mindis a sylnЬol for spidеrs?Philosophеrshavе еxplorеd a rаngе of rеsponsеs to this quеstion.An intuitivеly appеaliпg idеa is that symЬols rеsemblе their targеtsin thе world. Pеtеr'smеntal statе is aЬout spidеrs if it rеsеmЬlеsspidеrs.Tlris is a natural su8gеstionif thtlughts arе likе imаges, maps, or diagraпrs.Howеvеr, almost сеrгainly it Will not do. Меntal imagеs do rrot sееm to bе oЬjесtivеlysimilar to еnduring thrее-dimеnsionalphysiсal animals; thе appеаranсе of rеal similarity Ьеtwееnpiсturеs and things is an illusiсln gеnеr' atесlb1'thеwav lrumans irrtегpгеtpiсturеs.Pеtеr'sspidеr imagе wili rеsеmЬlе оthеrthоughtsmuсh morе than it геsеmЬlеsany animal. Мorеovеr, еvеn if somеmеntal statеs arе likе imаgеs, surеly most mеntal rеprеsеntatlonsarе not imagеlikе.Whirt is thе inragеthat сoггеspondsto thе thorrght ..Aristotlе Wasthе foundеr of logiс, arrd Еuсlid tlrе foundеr Of gеomеtry''? So thе rеlation Ьеtwееn symЬol and targеt is not a rеsепrЬlanсеrеlationship.But pеrhaps it is a саusa] rеlationship.Somе еvеnts аrе natural signs of оthеrs.Think in partiсulаr of instrurтеnts.An instrumеnr is а fuеl gaugе if thеrеis a rеliaЬlе геlatiorrЬеtwееn thе rеading on thе gаugе and thе fuеl in one'stank. That is what makеs a symЬol on thе gauge mеan ..quartеr full.'' Soan intеrnalstatеt>fPеtеr is ir spidеr syrrrlrolonly if it геliaЬly сovariеs with thеrеbеinga spidеr in his viсinity. Thе symЬol-targеtrеlationship is thе rеlаtionshipЬеtwееn аn innеr struсtrrrеand its еnvironmеntal сorrеlation: thе featurеof thе еnvironmеnt that сausеsthе innеr struсturеto light up. But this will proЬаЬlynot do еithеr. [n thе first instanсе,this piсturе appliеs i1t Ьеst to pеrсеption.Lots of my winе thоughts oссur prесisеly Ьесausе thеrе is no winеaЬout. But thе сrunсh proЬlеm is that this piсгurе sееms to makе it impossiЬlеfor us еvег to mаkе r-t-tistakеs, уеt surеly wе do. If Pеtеr is somеwhаf araсhnophoЬiс'arrd his friеrrdsplaguе him with сlеvеr imitаtion spidеrs, hе rvilloftеn think ..Spidеr!!''whеn thеrе is no spidеr around. Hе is misrеprеsеntinghis еnvironmеnt. Yеt aссording to thе сovariation piсturе t.,f thе symbol.taгgеt rеlationship' lrе would noс Ье misrеprеsеntirrgat all, ftlr his ..spidеr'' thoughts сovаry with thе сatеgory of spidегs or imitation spidеrs. Hеnсеthеy arе n()tsymЬols of spidеrs atiеr аll; thеir targеt is thе Ьroadеr сatеgoryof spider look-аlikеs (inсluding rеal spidеrs, гuЬЬеr spiders, аnd so forth).And sinсе Реtеr thirrks..Spidеr!!'' only in thе faсе of spidеr lookalikеs,hе has madе no mistakе. David Papinеau and Ruth Millikan hirvе suggеstеdan altегnativеviеw of thеrеlationshipЬеtwееnsyrrrbolsand rhеir targеtsthаt is Ьzrsеdon Ьiologiсаl funсtion.Thе Ьiologiсal funсtion of, say, thе pattеrn on oystеrсatсhеrеggs is сonсеaImеnt. Thosе еggs are саmouflаgeсl.Еggs that wеrе diffiсult for pгеdatolsto spot against typiсаl ЬaсkgгoLrndsof sand аnd dеЬris wеге morе likеly to hatсh than thosе that wеге еаsiеr to find. Tlris sеlесtivе histoгy is what makеsit truе to say that thе Ьiologiсal funсtion of thе pattеrn is сamouflаgе. on any partiсular еgg thе pi1ttеrnhas that Ьiofur-rсtionеven if it doеs not

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Рbilosoph1'сlf Еuolutirlnаrу Tbtlught havе thаt еffесt. T'hе pattеrn is supрсlsеd to сorrсеаl tlrе еgg еvеn if thе eggrs sееn anyway, and еvеn if thе egg is vеry еаsily sееn Ь..;;;. thе parеnt has laid it on whitе sand irgainst*ьi.ь it stands out. Similarlv, thotrghtshavе biologiсal funсtions' Thеir fr-rnсtionis to diгесt Ьеhаvior thаt adapts an orgаnism to a spесifiс fеaturе of its еnvironmеnt. Vervеt monkеys hаvе distinсtivе сalls and fеsponsеs trl thе siglrt of a |еoрard, and thеiг lеopard-rесognition thoughts are аbout lеopards Ьесаusе thеir funсtion is to ada.ptvеrvеt bеh.rv. tor to thе prеsеnсеof leopards in tlrеir еnvirсltrmеnt.Тhosе u..u.., with a dis. positiorr to sсramЬlе to thе top of trееs wЬеn thеy hаd а distinсtivеly lеopardy visual ехpегiеnсеwеrе rrrorе likеly to livе than thosе without it. So thе lеoрard rеsponsе mеans ..lеoparсl'' еvеn whеn it is a falsе alarm' for that disposition irr thе vеrvеt ехists аs a геsult of selесtionro. t.opn.а аvoidanсе. Тhis viеw of mеaning, of thе symЬol-world геlationship,ho, ,.,''. vеIy at. traсtivе fеaturеs.[tехplаins why wе Wa,'t tO say of thе vеrvеt thаt it is afraid of lеopards rathеr than Ьеing afraid of lеopi.rrdsаnd lеopard look.аlikеs еvеn though (I ltavе rro с]ouЬt)vеrvеts would ..,p.,nd th. ."-. Wаy to dummy lеopards сonstгrtсtеdЬy Ьеhavioral есologists. }.or lеtrpаrd dummiеs havе playеd no part in thе еvolution сrf vеrvеts and thеir еsсapе bеhaviors, so vеrvеt alarm сalls arе aЬout lеopards, not lесlpardlook-аlikеs. Тhis viеw of symЬols eхplains how it is possiЬiе t
Sсiеnсеand thе Mirror оf Physiсs Until thе l970s (pеrhapsеvеn latеr) рhilosoрhy of sсiеnсеrvas сlominаtеdby ехanrplеsdrawn tгom thе physiсai sсiеnсеs, еspесiallyphysiсs' Thе stаndard ехamрlеs of thеoг1,сhаngе inсludеd tlrе Сopеrrriсanrеvolution, the transition from Nеwtoniаn ссlnсерtionsof spaсе аnd .i''. to rеlаtivist .on..p.ion,, ond somеtimеs thе rеvolution in atomiс physiсs that sаw thе еstaЬlisl-rmеnt of quantllm mесhaniсs.Thеsе wеrе rrot thе only ехamples of sсiеnсеin thе wild, Ьut thеy wеrе stoсk eхamplеs, and rnarr,, оthеrs w... .l.a*,, frorn tlrе physiсal sсiеnсеstoo. Thеsе ехirmplеs .,'.o..,"g.d thе idеа tЬat а сorе lеаturе of sсiеnсеwas thе fоrmulation of gеnеral l,-.. smаll sеt oГ ехсеptronlеssgеnеrаl prinсiplеs tlrаt сhаraсtеrizеa sсiеntifiс " dtlnrain. thе епrpiriсisttradition еxеmplifiеd Ьy Nаgеl,sсlassiс .l.hеStrtlсturе .Within of Sсiепсе (Nagеl |961), tlrеrеwas g.,ud dеal tlf dеЬaгеaЬout thе naturе of "

thеsе gеnеral prinсi t i o n s o f n а г t t r еа s i highly сompасt sum ing сonсеptions of g еnсе tradеd in tlrсl geлeralizatlons. Мo, еpistеmology of sсre gеnеralizations' togс dеlivег quantitativе i t h е r е s u | to f s p е с i f i с sults of natural ехpеr fеrring its loсation fl еvidеntiаl wеight dе1 physiсs еnсouragеd a is the bаse cаsе: th< domains-сhеmistry а n d г h е i r g е n е r аl i z l r t izations. orrе of thе сl stгаtion that Kеplеr's сasе of NеWtonian m( fiсation of rhе rеl;rt physiсs. From thе lаtе 1960 undеr widе-rаnging fir thе physiсal sсiеnсеsv sсiеnсе thаt for.rglrtov ( | 9 7 0 | ,а n d t h е t r a d i LakаtosЪ ..dеgеnега

morphology of RiсЬar thе British rеsistanсе Тhonlas Kuhrl сut his trаining аs a historiаn rzozs (Kuhn 1962).TЬ ессentгiс Paui FеyеraЬ tion of thirrking aЬor-r history еmpЬаsizеd drl In suссеssivе sсiеntifiс г е p l а с е d . B u t t h е s ес r i t i o n w i t h p h y s i с se n d Kuhn) did thеy сhallе a n d p г е с i s еа n d q u a n г i Yеt this piсture fail Whсrlе-organism Ьiolсl gеnеral prinсiplеs that Есoiogy аnd еvolutioг for ехamplе, thе vulnе

Рllilosopbу rlf Еuolutioпаrу Tbought o сOnсеalthе еgg еvеn if thе еgg is ]asilYsееn Ьесаusе thе parеnt has ls сlut.Similаr[v,th
;ophy of sсiеnсеwas dominatеd Ьy :s,еspесiallyphysiсs. Thе stаndard l p с г n i с а nr е v o l u t i t l nt' h е t г а n s i t i o n l tiпiе to rеlativistсollсеptions' аnd ;iсs that sаW thе еstaЬlishmеnt of nly ехamplеs сlf sсiеnсе in thе wild' othеrs Wегеdrarvn from thе physigеd tlrе idеa that a сorе fеаturе of vs:a small sеt ot ехсеptionlеssgеn: domаin. iеd Ьy Nagеl's сlirssiс The Struсtиrе Ldеаl of dеЬatеzrЬoutthе nаturе of

thеsеgеnеral prinсiplеs: dеЬatе aЬout whеthеr thеy Wеrе aссuratе dеsсrip. tions of naturе as it rеally is, or whеthеr thеy wеrе Ьеttег undеrstood as highlyсornpaсt sunrmariеsof tlrе phеnomеna. Notwithstanding thеsе diffеring сonсеptionsof gеnеralizations,though, it was сommon grоund that sсiеnсе tradеd in thеm. Thе aim of sсiеnсе Was to find and rеfinе suсh gеnеralizations.Мorеovеr, this foсus еnсouгagеd a сеrtain piсturе of thе еpistеrnologyof sсiеnсe:sсiеntiliс warrant dегivеs from thе faсt that thеsе gеnеralizations,t
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Philoso1lhу of Еuolutionаrу Thought .Гlrеsе stoats. Ьirds еvolvеd in аn еnvironmеnt frее of any tеrrеstrialpгеdator аnd frее of any prеdator at аll that finds its prey Ьy smеll. But есology and еvolutionary biology rarеlу еnablе us to makе prесisе quantitativе prеdiсtions. Thеrе arе gеnеralizationsin Ьiology, and onе of thеm is thе fragility of island есosystеmsand thе vulnеraЬility of island Ьiota to ехtinсtion. But gеnеralizations of this kind arе nеithеr ехсеptionlеssnor quantitativе:thеy Ьеar littlе rеsеrnЬlanсеto Boylе's law. Biologists sееm to disсovеr сausal mесhanisms: natu[al sеlесtion' сompеtitivе ехсlusion' есologiсal suссеssion,and gеnе rеpliсаtion arrd transсription.But thе еffесtsof thеsесausal mесhanisms arе сontеxt spесifiс,and thosе сontеxts vaty ovеr spасе and timе. So thе disсovеry of mесhanisms doеs not translatе into ехсеptionlеssrеgularitiеsthat arе thе сonsеquеnсеs of thе opеration of thosе mесhanisms. Thеrе arе gеnеralizations about еvolution on islands: largе animals tеnd to gеt smallеr' and small аI-rimalstеnd to gеt largеr. But thеrе arе many exсеptionsto this gеnеralization. Мorеovеr, thе sirnplе piссuге of thе unifiсаtion of sсiеnсе fits Ьiology poorlу. Сhеmiсal propеrtiеs likе aсidity indеxеd, or Wеrе thought to indех' a singlе undеrlying physiсal propеrty that was itsеlf rеsponsiЬlе for thе phе. nomеnologiсal propеrtiеs of aсids. Еvеn in сhеmistry it is likеly that thе rеlationship bеtwееn сhеmiсal and physiсal propеrtiеs is vеry oftеn сomplех indееd. But this сomplеxity fiгst Ьесamе oЬvious in Ьiology, for сеll Ьiology and molесrrl:rrЬiology do Ilot сoIrform to thе modеl of rеduсtion suggеstеd Ьv aсidity (Kitсhеr 200з). Сеlls аге not mirасlе faсtoriеs:thеir biologiсal aсtivitiеs arе сonstrained Ьy physiсal prinсiplеs. To that ехtеnt physiсs rеаllyis thе thеory of еvеrything. Bur thе геlationship Ьеtwееn' say' thе сonсеpt of a dominant gеnе and thе undеrlying molесular mесhanismsrеsponsiЬlеfоr thе phеnotypiс silеnсе of onе of a pair of hеtеrozygous allеlеs turns out to bе vеry сomplех indееd. Finally' thе history of Ьiology is not a sеriеsof rеvolutions and rеplaсеmеnts.Thе history of Ьiology oftеn sееmsto manifеstinсrеmеntаl improvеmеnt.All sсiеnсеshavе thеir rеvisionsand falsе trails, but thе history of сеll Ьiology, plrysiology, gеnеtiсs' or еvеn еvolutionary Ьiology doеs rrot aЬound with major rеvеrsalsof сorе doсtrinеs сomparaЬlе with thе rеvolution in platе tесtoniсs in thе еarth sсiеnсеs.In short, it is hard to Ьoth takе Ьiology with full sеriousnеssas a sсiеnсеand aссеpt a сonсеption of sсi. еnсе dеrivеd from thе physiсal paradigms.Philosophеrs hаvе gonе Ьoth ways on this. Alех RоsеnЬеrg is thе пlost prominеnt of thosе who hаvе aссеptеd tlrе physiсists'сonсеptiоn of sсiеnсеand as 2lсonsеquеnсеhavе aссеptеdthе viеw that somе сomponеnts of Ьiology arе not quitе up to snuff (RosеnЬеrg 7994). John Dupr6 is thе most prominеnt сontеmporary who rеjесtsthе imagе of sсiеnсе in thе physiсist's mirror on thе grounds that it fails tсl fit Ьiology (Dupr6 2002). Most of thosе who work in philosophy of Ьiology arе сlosеr to Dupr6 than to RosеnЬеrg on this issuе: thеy think that еvolutionаry Ьiology is a parаdigrrr of a suссеssful sсiеnсe, and hеnсе thе physiсsЬasеd сonсеption of sсiеnсе is too narrow. Thеrе is no сonsеnsus' howеvеr, on ехасtly what is Wrong with thе physiсs modеl, or on how it nееds to bе еxtеnded.

In сonсlusion, philo way pump. It pumps many diffiсtrlt pгoЬlеm arisе out of thе еxtraс сеntury. And it рumps amplеs, tools, and mod losophy,s own projесts thе writings of Riсhar finеst and most suЬtlе blе (|996) is а susrаi Ьеautifully writtеn, thс Gould's viеws, see Tht pallingly long Ьut rеаs iсal matеrial сan bе sl B г u с e $ И е Ь е r( l 9 9 5 ) ' i synthеsis and post.syn I7еtt, Dаrшiп's Dапger splеndid ехaпrplеs of v: Seх апd Dеаtb: Аn Int Paul Griffiths (1999), с iсs in muсh morе dеtai

в|вL!oGRAPHY

Burt, A.' and R. Trivеrs.2 ЕIеmепts.CamЬridg Сain, A. J., and P' М. Shе nеmoralis.Hеrеditу4 1952.Thе еffесt nеmorirlis.Hеrеditу( ]954. Nаturаlsе Сarroll, R. L. 1997.Pаttе С а m Ь r i d g е[ I n i v е r s Сraсraft,J., and М. Dono oхford UnivеrsityPr Dаwkins, R. 1976.Тhе Sе 7982. Thе Ехtеltt \996. СlimbiпgN 2.О04.TЬе Апсеsr .!Иеidеnfеld аnd Niсol Dеnnеtt,D. С. 1995.Dаri Llfe. Nеw Yогk: Simс 200З. FreесlomЕt Dеpеw, D., аnd B. H. WЪ tbe Gеnеаlogl tlf Nаt -Г. D o Ь z h a n s k у ' 1 9 3 7 ,G е UnivеrsityPrеss. Dupгё,J.2002. Humапsс Еldrеdgе,N. 1995.Rсizlс

Philгэsophуof Еuolutiсlnаrу Тhought lеnt frее of any tеrrеstrial prеdator its prеy Ьy smеll. But есology and makе prесisе quantitativе prеdiс, and onе of thеm is thе fragility of island Ьiota to ехtinсtion. But gеn. 'ionlеssnor quantitativе:thеy Ьеar ts sееmto disсovеr сausаl mесhalusion' есologiсal suссеssion, аnd еffесtsof thеsе сausal mесhаnisms ry ovеr spaсе and timе. So thе disinto еxсеptionlеss rеgularitiеs that hosеmесhanisms.Thеrе arе gеnеr;е animals tеnd to gеt smallеr, and a r е m a n y е x с е p t i o n st o t h i s g е n е r шnifiсation of sсiеnсе fits Ьiology dеxеd, or wеrе thought to indеx, a was itsеlf rеsponsiЬlе for thе phеr сhеmistry it is likеly that thе rеlapropеrtiеs is vеry oftеn сomplеx lЬvious in Ьiology, for сеll Ьiology l thе modеl of rеduсtion suggеstеd iraсlе fасtoriеs:thеir Ьiologiсal aсllеs.To that ехtеnt physiсs rеally is ;hip Ьеtwееn' say' thе сonсеpt of a lar mесhanisms rеsponsiЬlе for thе )tеrozygousallеlеs turns out to Ье of biology is not a sеriеs of revolu'logy oftеn sееms to manifеst inсrе:ir rеvisions and falsе trails' Ьut thе tiсs, or еvеn еvolutionary Ьiology :orеdoсtrinеsсomparaЬlе with thе сiеnсеs.In shоrt, it is hard to Ьoth nсе and aссеpt a сonсеption of sсiPhilosophеrshavе gonе Ьoth ways rinеnt of thosе who havе aссeptеd ls a сonsеquеnсеhavе aссеptеd thе е not quitе up to snuff (RosеnЬеrg сontеmporary who rеjесts thе imthе gгounds that it fails to fit Ьiolvork in philosophy of Ьiology arе is issuе:thеy think that evolution;l sсiеnсе,and hеnсе thе physiсsv. Thеrе is no сonsеnsus. howеvеr. :s modеl, or on how it nееds to Ье

In сonсlusion, philosophy of еvolutionary Ьiology aсts as a typе of twoWay pump. It pumps philosophy into еvolutionary thеory, for thеrе arе many diffiсult proЬlems of intеrprеtation' сlarifiсation, and integration that arisе out of thе еxtraordinary dynamism of thе lifе sсiеnсеs ovеr thе past сеntury.And it pumps еvolutionary Ьiology into philosophy: a strеam of ехamplеs,tools, and modеls that сan pеrhaps Ье adaptеd to drivе forwаrd philosophy's own projесts. If you want to rеad morе, I suggеst you turn first to thе wгitings of Riсhard Dawkins: The Ехteпdеd Phеnotуpe (1982) is his finеstand most suЬtlе dеfеще of gеnе sеlесtiоn;Сlimbiпg Мount Improbаble (1996) is a sustainеd and сonvinсing dеfеnsе of grаdualism. Both are Ьеautifully writtеn' though Thе Ехtепded Phепotуpe is quitе tесhniсal. For Gould's viеws, see Tbe Structure of Еuolutionаrу Tbeorу Q002),It is аppallingly long Ьut rеasonably rеadaЬlе, and a good dеal of thе purеly historiсal matеrial сan Ье skipped. Dаrtuiпism Еuoluiпg' Ьy David Dеpеw and Bruсе \WеЬеr(1995), is a good оvеrviеw of thе historiсal dеvеlopmеnt of synthеsisand post-synthеsisеvolutionary Ьiology. Two Ьooks Ьy Dan Dеnлеtt' Dаrluiп's Dаngеroиs Ideа (1995) and Freedom Еuoluеs (2003), arе splеndidехamplеs of valuе of еvolutionary insights within philosophy itsеlf. Sех апd Deаth: Ап lпtroductioп to tbе Philosophу of Biologу' Ьy mе and Paul Griffiths \1999), сovеrs many of thе issuеs of this еssay and othеr topiсs in muсh morе dеtail.

BIBLIOGRAPHY Burt,А.' and R. Trivеrs.2005. Gепеsiп Сoпflict:The Biologу of SеlfishGeпetiс Еlеmепts'СamЬridgе,MA: Нarvard UnivеrsityPrеss. Сain,A. J., and P. М. Shеppard.1950.Sеlесtionin thе polymorphiсland snail Сеpaеa nеmoralis.Hеrеditу4: 27 5-294' 1952'The еffесtsof naturalsеlесtionon body сolouг in thе land snail Сеpaеa nеmoralis.Hereditу6: 217_231. 1954.Natural sеlесtionin Сеpаеa.Gепetiсs39:89-716. Сarroll,R. L. \997 . Pаttеrпапd Proсеssiп VеrtеbrаtеЕuolutiсlп.СamЬridgе: СambridgеUnivеrsityPrеss. Сraсraft,J., аnd M. Donoghuе'еds.2004. Assembliпgthе Тrее of Life. Oхford: oxford UnivеrsityPrеss. Dawkins,R. 1976. Tbе SеlfishGeпе. Охford: oxford UnivеrsityPrеss. |982. Thе ЕхtепdеdPhепсltуpе.Oхfоrd: oхford UnivеrsityPrеss. .!(. .W. 1996.Сlimbing Мouпt Improbаble.Nеw York: Norton. 2О04.Thе Aпсеstor'sTаle:А Pilgrimаgеto thе Dаtuп of Life. London: Wеidеnfеldand Niсolson. Dеnnеtt, D. с. 1995. Dаn.uiп,sDапgеrсlusIdеа:Еuolиtklп апd thе Меапiпgsof Llfe. Nеw York: Simon and Sсhustеr. 2ОО3.FrеedomЕuoluеs.Nеw York: Viking. Depеw,D., аnd B. H..!ИеЬеr.\995. Dаnuiпism Еuoluiпg:SуstemsDупаmiсs апd thе Gепеаlсlgуof Nаturаl Sеlесtioп.СamЬridgе'МA: MIT Prеss. Dobzhansky, T. \937. Gепetiсsапd thе Оrigin of Spесles.Nеw York: СolumЬia UnivеrsityPrеss. Duprё'J. 2002. Hиmапs апd Оthеr Апimаls. Oхford: СlarеndonPrеss. Еldrеdgе' N. 1995. RеiпuепtingDаrшiп. Nеw York: John Wilеy and Sоns.

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Philosophу of Еuolиtiсlпаrу Tbсlиght Еldrеdgе,N., and S. J. Gould. 1972.Punсtuatеd еquiliЬria:An altеrnativе to phylеtiс gradualism.In T. J. Sсhopf,еd.,Мodels iп Pаlеobirlkryу,82_115. Sаn Franсisсo: Frееman,Сoopеr. Fеyеrabеnd, P.K. 1975.АgаiпstМеthod.London:Nеw Lеft Books. Fishеr,R. A. 19з0. Thе CепetiсаlThеorу of Nаturаl Sеlесtiсlп.Oхford: Oхford UnivеrsityPrеss. Fishеr,R. A., and Е. B. Ford. 1947.Thesprеadof a gеnеin naturalсonditionsin a сolony of thе moth Pаnахiа domiпцlа L, Hеrеditу |: 1'4З-1,74. Gould, S. J. 2002. The Struсtиreof ЕuolutiсlпаrуThеorу.СamЬridgе,МA: Harvard UnivеrsityPrеss. Gould, S. J., and Е. A. Lloyd. 1999.Individuаlityand аdapta'tion aсrosslеvеlsof sеlесtion:How shall wе namеand gеnеralizеthе unit of Dаrwinism?Proсееdiпgs of thе NаtioпаlАсаdеmуof SсiеnсеsUSA 96:1\904-11909' Griffiths,P. Е. 20О2.Мolесular and dеvеlopmеntalЬiology.In P. K. N4aсhаmеrаnd M. SilЬеrstеin,eds',Thе BlасktuеIlGиide to thе Phibsophу of Sсienсе, 252_27\.Nеw York: Blaсkwеll. Griffiths,P. Е., and R. D. Grаy. 1994.Dеvеlopmеntаl systеmsand еvоlutionary еxplanation. Jourпаlof Рhilosophу91, nо. 6:277_З05. Griffiths'P. Е., and Е. Nеumann-Неld.1999.Thе mаny fасеsof thе gеnе.BioSсiепсe 49, no. 8: 656-662. Gоdfrеy-Smith' P. 2000.Information, aгЬitrarinеss, and sеlесtion: Сommеntson Mаynard Smith.PДllosсlphуof Sсiеnсe67: 2О2-207. Haldanе,J. B. S. 1931.A mathеmatiсal thеoryof naturаland аrtifiсialsеlесtion. Pt. VIII. МеtastaЬlеpopulations.Trапsасtktпsof thе СаmbridgеPhilosopbiсаl Sociеtу27: 1З7-142. Hull, D. L. 1988.Scieпсeаs а Proсеss.Сhiсago:Univеrsityof СhiсagоPrеss. Joyсе,R. 2О06.Тhе Еuolиtioп of Мorаlitу, СamЬridgе,МA: МIT Prеss. Kеttlеwеll,tI. B. D. 1955. Sеlесtionехpеrimеntson industriаlmеlаnismin thе Lеpidoptеra.Ilеrеditу 9: 323_342' 1956.Furthеrsеlесtionеxpеrimеnts оn industrialmеlanismin thе Lеpidoptеra. H e r е d i t у| О : 2 8 7 - З 0 1 . Kitсhеr, P. 2003. Iп Мепdеl'sМirror: PhilosophiсаlRе|lесtioпsoп Biologу. Oхford: Oxford UnivеrsityPrеss. Kuhn' T. 1957. Thе Сo1lerпiсапReuс-llиtioп. Сambridgе'МA: Нarvard Univеrsity Prеss. \962. Thе Struсturеof SciепtфсReuolutioпs.Сhiсago:Univеrsityof Сhiсago Prеss. Lakatos'|. \97О.Fаlsifiсationand thе mеthodologyof sсiеntifiсrеsеarсhprogrammеs. In I. Lakаtos and A. Мusgгavе,еds.,Сritiсism апd thе GrotutЬ of Kпott,lеdgе, 9|-19 5. Сambridgе:СаmЬridgеUnivеrsityPrеss. Lakatоs,I., and A. Musgravе'еds. 1970. Сritiсism апd thе Grrlшth сf Kпoшledgе. СamЬridgе:СamЬridgеUnivеrsityPrеss. Lеwontin,R. с. 1970.Thе unitsof sеlесtion. Aппuаl Rеuiешof Есologуапd Sуstеmаtiсs1: 1'_|4. Мaynard Smith'J. 2000a.Thе сonсеptof informаtionin biologу.Pbiloso1lhуof Sсiепсе67: 177-|94. 2000Ь.Rеply to сommеntariеs. PhilrlsophусlfSсieпсe67:214-218, Мayr, Е. 1942. Sуstеmаtiсsапd thе origiп of Speсiеs.Nеw York: СolumЬia UnivеrsityPrеss. Мillikan, R. 1989a.Biosеmаntiсs. Jourпаl of Philosophу86 281'-297' 1989Ь.In dеfеnsе
owеn, R. 1848. oп th London: Voorst. 1849. Оп thе| oyаma, S. 1'985.The С Prеss. Oyama, S., P. Е. Griffit DеuеlopmепtаlSу Papinеаu'D. 2О03.Тht Еuolutioп, апd Prс Poppеr,K. R. 1959.T, 1963. Сoпjесt RosеnЬеrg,t. \994. lп Univеrsity of Сhiс: Rusе, N4. |986.Таkiпg oxford: Blaсkwеl 2О07. Сhаrlеs' Sаrkar' S. 2000. Inforп N4aynardSmith.P Simpson,G. G. 1944.i Univеrsity Prеss. "l953.Тhе Маj Prеss. SoЬеr,Е. |984, Тhе Nс Foсиs. Сambridgе SoЬеr,Е., and D. S. !Иi Uпselfish Bеhаuiсl StеЬЬins,G. L. 1950.1 Univеrsity Prеss. Stеrеlny,K. 2000.Thе Smith on informa 20О3.Tbougb Stеrеlny'K., and P. Е. ( Philosophу of Biot .sИilliams, G' С. \966., Univеrsity Prеss. 1992' Nаturаl oхford Univеrsity .'iИright' S. ]931. Еvolu 1 9 3 2 .T h е r o l еvolution.Proсее з56-366.

Pbilсlsopbу сlf Еuolutionаrу d еquiliЬria:An altеrnativеto phylеtiс Pаleobiсlklgу''82-1 l5. S;rn Fr;rnсisсo: lorr:Nсw Lеft Boсlks. аturаI Sеlесtklz. oхfоrd: oxford Lof a gеnеin nаtural сonditions in a ] е r е d i t у1 : 1 4 З _ 1 7 4 . rу Thеrlrу, СamЬridgе, МA: Harvard ,tv and аdaptationaсross lеvеls of Zе thе unit оf Daгwinism? Prсlсacdings 9 6 :1 | 9 0 4 - | 1 9 О 9 , :ntal biology. In P. K. Масlrаmег аnd to thе Philosrlphу сlf Sсiепсе, m е n т а 5l y s t е m а s nd еvoIuгionarу , 6 : 2 7 7 _ З 0 '5 .hе many faсеs of thе gеnе. BioSсieпсe nеss,and sеlесtion:Сommеnts on : 202-2('t7. of natural and artifiсiаl sеlесtion. ioпs of thе СаlпbriLlge Pbiloso1lhiсаl l: Univегsityof ChiсargoРrеss. rrrЬridgе,МA; МIT Prеss. ts on indlrstriаlmеlanism in thе industгiа]mеlirnismin thе l,еpidoptегa. 'ЬiсаI Rе|lесtit.ltls on Вiolсlgy. oxford; )amЬridgе,MA: Hагvard University |utions,Сhiсago: Univеrsity of Iogvof sсiеntifiсrеsеarсh PгOgгаmmеs. :ism апd thе Сrсltuth o| Kпou,'lеdgе, y Pгеss. .ism апd tbе Groluth сl|.Knolulеdgе. \ппuаl Rеuiеtt'rf Есologу апd "matiot1in Ьiology. Philosсl1l|lу of ,lphуof Sсiепсе67:214_218. ipеciеs.Nеw York: СolumЬia hilosophу 86 281_297. Philosophуoi Sсiепсе 56: 288_302. ms iп tЬе Lсlgiс of Sсiепtifiс Disсouеrу.

Thought

owеn, R. 1'848. Оп the Archetl'Pe аnd Homologies of thе Vertеbrаtе Skеlеtoп. London: Voorst. \849. Оп thе Nаturе of Limbs. London: Voorst. oyama, S. 1985. Thе oпtogеttу of Iпformаtioп. СamЬrtdgе: Сarnbridgе Univеrsity Press. oyamа' S., P. Е. Griffiths, and R. D. Gray, еds. 20О"t.Сусlеs of Сoпtiпgеnсу: DеуеloРmеntаl Sуstems апd Еuolutioll. СamЬгidgе, МA: MIT Prеss. Papinеau,D. 2003. TЬе Roots of Rеаsсlп: Philosophiсаl Еssауs oп Ratioпаlitу, Еuolиtioп, апd Probаbili,}'. Nеw York: Oхford Univегsity Prеss. Poppеr, K. R. 1959. Thе Logiс,oi Sсieпtifiс Disсouеrу. London: Hutсhinson. \963. Сoпjесturеs апd Refиtаtioпs. Lоndon: Routlеdgе and Kеgan Paul. Rosеnbеrg,^, |994. lпstrumепtаl Biobgу or thе Disuпitу o|.Sсiепсе. СЪiсugо' Univеrsity of Сhiсago Prеss. Rusе, М. 1986. Tаkiпg Dаrtaiп Sеriсluslу: А Nсttиrаlistiс Аpproасh to Philosophу. oxford: Blaсkwеll. 2007. Сhаrlеs Dаrш,iп. oxford: Blасkwеll. Sarkar, S. 2000. Informаtion in gеnеtiсs and dеvеlopmеntal Ьiology: Сommеnts on Маynard Smith. PДilсlsсlphу of Sсiеnсе 67:208-2|З. Simpson' G. G' 1944. Tеmpo апd Мode in Еuolutioп. Nеw York: СоlumЬiа Urrivеrsity Prеss. 1953' The Маjor Fеаturеs of Еuolutklz. Nеw York: СolumЬia Univегsrry Рrеss. Sobеr' Е. 1984. Тhe Nаtllrе of Sеlесtiсlп:Еuolиtioпаrу Thеorу iп Philosophiсаl Focцs. СaпЬridgе, МA: МlТ Prеss. Sobеr,Е., and D. S. Wilson. 1998. Uпto Оthers: Thе Еuolutioп апd Рsусhologу of Uпsеlfish Bebаuior. CamЬгidgе, МA: Harvаrd Univеrsity Prеss. StеЬЬins'G. L. 1950. Vаriаtion аnd Еuolution in Plаnts. Nеw York: Columbiа Univеrsity Prеss. Stеrеlny,K. 2000. Thе ..gеnеtiсprogram'' program: A сommеntarv on Мaynard Smith on infoгInаtion in Ьiology. Philсlsopbу of Sсiеllcе 67: 1,95-20l. 2ООЗ. Thought in а Нostilе Worl/' Nеw York: Blaсkwеll. Stеrеlny,K., аnd Р. Е. Griffiths.1999. Seх апd Dеаth: Ап ]ntrodlrction to Philosophу of Biologу. Chiсago: Univегsity of Chiсago Prеss. Williаms, G. С' 1966. Аdаptаtiсlп аnd Nаturаl Sеlесtioп, Prinсеton. NI: Рrinсеton UnivеrsityPгеss. 1992. Nаtцrаl Sеlесtioп: Donlаins, Lеt,еls, аnd Сhаllеnge-s. Nеw York: oхford Univеrsity Prеss. Wгight'S. 1931. Еvolution in Меndеliаn populаtions. Gепеtiсs 16:97-159. |932. TЬe rolеs of mutation' inЬrееding, сrossЬrееdingand sеlесtlon ln еvolrrtion. Procеedings сlf thе Siхth Intеrпаtioпаl Сoпgrеss of Gеnеtics 1: з56-з66.

329

Еvolution and Soсiеty NIаnfrеdD. Lаиbiсhlеr аnd Jаnе Маiensсhеin

Еvolution and soсiеty arе сonnесtеd in many diffеrеnt ways. First and forе. most' humans' as a pгoduсt of еvolution, livе in divегsе soсiеtiеs.Thеsе arе an outсomе of еvolution, alЬеit in morе сomplех and oftеn morе indirесt ways than thе еvolцtion of dirесt morphologiсаl аnd physiologiсal adapta. tions. Sесond' thе initial dеvеlopmеnt of еvolutionary thеory oссurrеd in а spесifiс soсial miliеu сonduсivе to this pаrriсular intеllесtual endеavor, and suЬsеquеnt dеvеlopmеnt of еvolutionary thеory has also rеflесtеd its еvolving historiсal sеttings. Еvolutionary thеory, likе any othеr sсiеnсе, has thus Ьееn thе produсt of a partiсular human soсiеty.Finally, and as proЬaЬly thе most visiЬlе сonnесtion of еvolution and soсiеty, еspесially in thе Unitеd Statеs,wе find surprisingly pеrsistеnt dеЬatеs aЬout whеthеr еvolution or somе form of сrеationism aссounts for thе origin of spесiеs (аs Еugеniе С. Sсott disсussеs in thе main еssay ..Amеriсan Antiеvolutionism: Rеtгospесt and Prospeсt'' in this volumе). At somе timеs, in somе plaсеs, and in somе wаys' soсiеty has еnthusiilstiсally еmЬraсеd еvolution; at othеr timеs аnd plaсеs and in othеr waуs, soсiеty has not. In thе proсеss euolиtioп has mеant diffеrеnt things, as has soсietу..Wе thеrеforе start with dеfinitions and thеn look at soсiеty's impaсt on еvolution in two ways: thе way in whiсh soсiеty in thе sеnsе of soсial' сultural, and intеllесtual сontехt has shapеd еvolutionary thеory, and also thе soсial rесеption of еvolution. Thеn wе turn thе dirесtion of influеnсе around and addrеss how еvolutionary thеory today and in thе past has сontriЬutеd to ехplanations of soсiеty.In сonсlusion wе disсtlssсurrеnt rеlations bеtwееn еvolution and soсiеty in a forwаrd-looking way. .Wе do not foсus on muсh-disсussеd rеlzrtionshipssuсh аs standard irrtеrprеtations of soсial Darwinism or rеtraсе thе lristory of ways in whiсh soсial сommеntators havе usеd (and misusеd) еvolr.rtion.Thеrе is suсh а riсh litеraturе in thеsе gеnеral arеas that any gеnеral Googlе or Amazon sеarсh will yiеld dozеns of offеrings, of whiсh Сarl Dеglеr's Iп Seаrсh of Hиmап Nаturе: The Decliпе апd Rеuiuаl of Dаrtuiпism iп Аmеriсаn Soсiаl Thoиght (1992| or Riсhard Hofstadtеr's Soсiаl Dаrшinism iп Amеriсап Тhought (1959) arе just ЗЗ0

two wеll-knoц,n аnd < Spеnсеr, Pеtеr Krоpol soсial thinkеrs who in tеrs in suсh rесеnt Ьo< епсe: Dеsigпiпg Nаtu familiar popularizеrs Rathеr, wе еxplorе lе soсiеty Ьv аsking аЬo

Dеfinitions

Bу еuolиtioп Wе mеa еral еvolutionary idеа сhangе of population and lеad to divеrgе adaptеd tо thеir еnvi ally, with variations < and spесiеs аnd popu stant thеmеs: аl[ ассo pеrnaturalism as a с( еnvironmеnt tlrаt in vorеd arе Ьetter аdаp tions that mattеr for (

lеarning bеtweеn gеn mission. .Wе also sharе thе r ory of еvolution is сt somе timеs in thе сo othеr of rhеsеthеoгiе ity, strugglе ;rrrdсom; all part of еvolutionа сonsists of irrtеrсonn this еssay. Bу soсiеtу wе dеsig thе rеlеvant еlеmеntс fесt many othеrs. In t tingеnt, аnd populist bе taught in thе sсhос mands а сrеationistа сial сolrorts plаy dif groups as wе go аlon1 of (human) soсiеtiеs mеans any group of struсturеd way and ' 19751Boуd and Riсh

Еuolutioп апd Soсiеtу

)с1еty аnd

two wеll-known and diffеrеnt typеs of ехamplеs. Rеadеrs сan look to HеrЬert Spеnсеr,Pеtеr Kropotkin, Andrеw Сarnеgiе, and othеr popular еxamplеs of soсial thinkеrs who invokеd еvolution, or they сan takе up thе еvolution сhaptеrsin suсh rесеnt Ьooks as Bеrnard Lightman's Viсtoriаn Popиlаrizеrs of Sсieпсе:Desigпi11gl\Iaturеfсlr |'treшAudieпcеs (2007) for an introduсtion to lеss familiar populaгizеrs. Again, it is nоt on this wеll-trod ground that wе roam. Rathеr, wе ехplorе lеss familiаr aspесts of thе intеrsесtions of еvolution and soсiеtyЬy asking aЬout thе rеlationships in a variеty of ways.

Dеfinitions

rny diffеrеnt ways. First and forеlivе in divеrsе soсiеtiеs.Thеsе аrе сomplех and oftеn morе indirесt llogiсal and physiologiсal adaptaеvolutionary thеory oссurrеd in a rtiсular intеllесtual еndеavor, and rеory has also rеflесtеd its еvolving lе any othеr sсiеnсе' has thus bееn Finally' аnd as proЬaЬly thе most , еspесiallyin thе Unitеd Statеs,wе мhеthеrеvolution or somе form of сiеs (as Еugеniе С. Sсott disсussеs nism: Rеtrospесt and Prospесt'' in omе Ways' soсiеty has еnthusiasti. n d p l a с е sa n d i n o t h е г w a y s ' s o с i as mеant diffеrеnt things, as has s and thеn look at soсiеty's impaсt h soсiеtyin thе sеnsеof soсial, сulеvolutionarythеory, and also thе n thе dirесtion of influеnсе around ay and in thе past has сontriЬutеd .е disсussсurrеnt rеlations Ьеtwееn 3 way. donships suсh as standard intеrprеrе history of ways in whiсh soсial olution. Thеrе is suсh a riсh litеraral Googlе oг Amazon sеarсh will эg|er,sIп Seаrсh of Hиmап Nаtиrе: Аmеriсаn Soсiаl Thought (1'992) ot Americап Thought (1959) arе just

Bу euolutioп wе mеan thе еvolutionаry thеory of Ьiologists rathеr than gеnеrаl еvolutionary idеаs, thаt is, naturalistiс, matеrialistiс еxplanations of thе сhange of populations ovеr timе suсh that inhеritеd variations arе prеsеrvеd and lеad to divеrgеnсе of forms and thе origin of nеw spесiеs that arе adaptеdto thеir еnvironmеnts.This proсеss сan happеn morе or lеss gradually' with variаtions of various sorts' inhеritanсе working in сomplеХ ways' and spесiеsand populations dеfinеd diffеrеntly.Nonеthеlеss, thеrе aге сonstant thеmеs: all aссounts of еvolution Ьеgin with naturalism rathеr than supеrnaturalismas a сorе assumption. Al1 assumе that organisms еxist in an еnvironmеnt that in еffесt favors somе variations ovеr othеrs sinсе thе favorеd arе Ьetter аdа|lted' 1rnd all vеrsions assumе that it is inhеritеd variations that mattеr for еvolution, though inhеritanсе may сomе сulturally with lеarning Ьеtwееn gеnеrations' as wеll as Ьiologiсally through gеnеtiс transmission. !Ие also sharе thе viеw of Еrnst Мayr and othеrs that thе Darwinian thеory of еvolution is сomposеd of a variеty of sеparatе thеoriеs, and that аt somе timеs in the сoursе of thе history of еvolutionаry Ьiology onе or thе othеrof thеsеthеoriеs dominаtеd thе dеbatеs(Mayr 1982I. Variatiоn, hеrеdity, strugglе and сompеtition, and еmеrgеnсе and prеsеrvation of thе nеw аrе all part of еvolutionary thеory. Indееd, еvоlutionary thеory is сomplех and сonsists of intеrсonneсtеd сomponеnts that we еxplоrе in diffеrеnt ways in this еssay. Bу societу wе dеsignatеa variеty of kinds of soсial groups. In somе сasеs thе rеlеvant еlemеnt of soсiеty сеnters on lеadеrs who makе dесisions that affесtmany othеrs. In othеr сasеs thе rеlеvant soсial group is morе loсal, сontingеnt'and populist, as whеn сiviс lеadеrs may agгее that еvolution should Ьеtaughtin thе sсhools in any сivilizеd soсiеty' Ьut a voсal popular group dеmandsa сrеationistantiеvolution aссount of thе oгigin of man. Diffеrеnt soсial сohorts play diffеrеnt rolеs, oЬviously, аnd wе will look at diffеrеnt groupsas wе go along. Similarly, whеn wе disсuss еvolutionary ехplanations of (human) soсiеtiеs, wе follow an еqually сatholiс approaсh; soсietу Ьere mеansany group of animals or humans that intеraсt with еасh othеr in a struсturеd wаy and whosе survival dеpеnds on thеsе intеraсtions (.lfilson 1975;Boyd and Riсhеrson 1985; Kupеr 1994).

ЗЗ1

ЗЗ2

Еuolutklп апd Societу

Еvolutionary Thеоry Shapеd Ьy Soсiеty Еvolutionary thеory еxists in сеrtain soсiеtiеs аnd is dеvеlopеd Ьy mеmЬеrs of thеsе soсiеtiеs.That muсh is oЬvious. Darwin is thе mоst visiЬlе сеntral playеr, and historiаns havе shown thе signifiсanсе of thе fасts that soсially Darwin wаs uppеr middlе сlass and a Viсtorian Еnglishman. For ехamplе, thе British gеntlеman would prеsumaЬly havе found it еasiеr than thе poor son of a long-poor working-сlass family to сomе to Darwin's viеw of inhеri. t a n с е a s a p г o g г е s s i v еа n d p o s i t i v е f o r с е i n p r е s е r v i n gv а r i а t i o n o г t o s е е hеrеdity as еnaЬling rathеr than сonstraining. Thе way Darwin saw thе world from Н.МS Beаgle was surеly shapеd Ьy his сontехt and valuеs, as historiаns havе shown (Dеsmond and Мoorе 1991; Browne 1'995,2003;Нodgе and Radiсk 2003). His world Was thе riсhly Ьut gеntly еntangledЬank of an Еnglish gardеn rathеr than аn arid dеsert, a divеrsе and pungеnt rain forest, or an Alpinе tundra, еасh of whiсh might havе lеd him to diffеrеnt quеstions and еmphasеs. Furthеrmorе, as Darwin sсholars havе dеmonstratеd сlеarly, thе British .sИilliam Palеy saw сontехt of natural thеology shapеd еvolutionary thеory. еaсh organism and еaсh typе as adаptеd to its plaсе in thе world. Of сoursе' it was Palеy's Angliсan God thе Crеator who had donе thе adapting in that сasе, but thе fit of lifе form to еnvironmеnt сarriеd ovеr nеatly to Darwin's viеw of lifе. Truе, a Thomas RoЬеrt Malthus might point to thе human есo. nomiс dilеmmas intrinsiс in thе tеndеnсy of еvеry individual to inсгеasеinto a population that rapidly outgrows availaЬlе rеsourсеs.But Мalthus did not сall into quеstion that humans wеrе adaptеd to thеir еnvironmеnt. Indееd, thе tеndеnсy to produсе too many individuals just givеs naturе thе opportunity to сhoose somе ovеr othеrs. Or, as Malthus suggеstеd, pеrhaps man сould do thе сhoosing with wisе population сontrol. At any ratе, soсial viеws shapеd thе еvolutionary thеory that еmеrgеd,and thе rеsultswеrе optimistiс. For Мalthus, population сontrol would makе lifе Ьеttеr for еaсh pеrson and ..hеalthy,vigorous, and happy'' for soсiеty as a wholе. For Darwin, only thе would survivе and rеproduсе. A happy piсturе indeеd (Rusе 1979,2003; Hodgе and Radiсk 2003). Anothеr part of Darwin's Viсtorian miliеu that was ехtrеmеly important for his еvеntual formulation of thе thеory of natural sеlесtionas an ехplanation of еvolutionary сhangе was his сlosе сontaсt ovеr many yеars with many animаl and plant brееdеrs(Brownе 2003). Indееd,thе сlosе сompаrison Ьеtwееn artifiсial sеlесtion (with morphologiсal and Ьеhavioral сhangеs in populations that сould Ье induсеd Ьy сontinuеd Ьrееding)and natural sеlесtion (сhangеsthat would Ье a rеsult of thе ..strugglеfor ехistеnсе''in naturе) is a ..long major part of Darwin's argumеnt'' Thе Gеrmаn intеllесtual movеmеnt Nаturphilosophiе, with its romantiс сonсеption of naturе, Ьrought othеr pеrspесtivеs that shapеd еvolutionary thеory as it playеd out in Gеrmany. Johann Wolfgang von Goеthе's organiсism that saw an unfolding of form' Friеdriсh Sсhеlling and Gеorg Hеgеl's

assumptions of unitl soсiеty sharеd thе as сhangе ovеr timе tha 2002; Riсhards 200, thе intеllесtual еnvi partiсular vеrsion of progrеssivе impliсat an ехpliсitly and есс impaсt, just аs soсiе .What was sееn as rеflесts also сеntury ory (Bowlеr 1983)'s randomly arising vz and a foсus on thе i ganism in its еnviror prеtations thаt app( rеformеrs who wеrе tiс dеtеrminist or hе ary thеory, and thе с If thе hеritablе variа prеsumably Ье influt .Wе сannot ovеrеп ing soсiеty, though Hеrе thе point is th еvolutionаry thеory, to ask and whiсh as сеrtainty whеrе som as wеll as intеrnal t study еvoiution: nаt trol and manipulatir wholе orgаnisms, pi

parts likе bеhaviors .$Иеisman August 1'892 Kеimplаsmсl с еnvironmеntal influс tеrial of еvolution, р pеtition among his аlong visiblе сhrom matеrial units, was quеstions aЬout hov thе finе dеtails of th< Was part of a sсiеnti miсrosсopiс oЬsеrv еaсh organism, and .!Иеismann's еvolt impaсt on thе inhе

Еuolutiсln апd Soсiеtу

oсlеty tiеs аnd is dеvеlopеd Ьy mеmЬеrs Darwin is thе most visiЬlе сеntral nifiсanсе of thе faсts that soсially ]torian Еnglishman. F.оr еxamplе, ravе found it еasiеr thzrnthе poor ) сomе to Darwin's viеw of inhеriin prеsеrving variatiс;n or to sее ining. Thе way Dаrwin saw thе l by his соntеХtand vаluеs, as his1 9 9 1 ;B r o w n e 1 ' 9 9 5 , 2 0 0 З ;H o d g е ly Ьut gеntly еntirnglеdЬank of an а divеrsеand pungеnt rain forеst, t а v еl е d h i m r o d i f f е r е n tq u е s t i o n s dеmоnstratеdсlеarly, thе British ionaгy thеory. !Иillian-rPаlеy saw l its plaсе in thе world. of сoursе, ,ho had donе the adapting in that rt сarriеd ovеr nеatly to Darwin's Lusmight point to thе human есo' f е v е r yi n d i v i d t r a гl о i r l с r е a s еi n г о tlе rеsourсеs.But Мalthus did not tеd to thеir еnviгonnrеnt.Indееd, rals just givеs naturе thе opportuМalthLrs suggеstеd,pеrhaps man l сontrol. At any гаtе, soсi:rlviеws : d ' a n d t h е r е s u l t sw е г е o p t i m i s t i с . rkе lifе Ьеttеr for еaсh pеrson and rе ..hеalthy,vigorous, and happy'' iсturе indееd (Rusе 1979' 20ОЗ: i е u t h i r tW a s е x t r е m е l y i m p o r t a n t lf natttralsеlесtionas an еxplana)ntaсt ovеr many yеars with many Indееd,thе сlosе сomparison Ьеа l a n d h е l r a v i o r асl h а n g е si n p o p :d Ьrееding)and natural sеlесtion lgglеfor еxistеnсе''in naturе) is a 'urphilоsophie'with irs гomаntiс )есtivеsthat shapеd еvolutionary n.Wolfgаngvon Goеthе's organiriсh Sсhеlling and Gеorg Hеgеl's

assumptions of unity of naturе, and Karl Маrх's sеarсh for an unfolding of soсiеtysharеd thе zrssumptionsof еmеrgеnсе or of form from nonform and of сhаngеovеr time that lеads to irlprovеmеnt:rnd progress (Rusе 1996; Мoсеk 2002; Riсhards 2002)' Thеsе soсial and philosophiсal thrеads hеlpеd shapе thе intеllесtual еnvironmеnt into whiсh еvolution arrivеd. Еrnst Haесkеl's pаrtiсular vеrsion of еvolutionary thеory in Gеrmany sharеd thе positivе and progrеssivеimpliсаtions of еvolutionary сhangе and dеvеlopеd thе idеas in an еxpliсitly and ессеr\triсallymаtеrialistiс wаy thаt hаd tгеmеndous soсial impaсt,just as soсiеty had shapеd thе sсiеntifiсidеas. ..eсlipsе of Darwinism', at thе еnd of the ninеtееnth What was sееn as an сеntury also rеflесts impaсts from outsidе sсiеnсе itsеlf on еvolutionary thеory (Bowlеr 198з), shifting away from rеlianсе orr what Dаrwin hаd sееn as randomly arising variations. Меndеlism intгodцсеd gеnеs, hеritаblе units' and a foсus on thе intеrnal woгkings of thе oгganism morе than on thе organism in its еnviгonmеnt. This brought a shift from thе morе organiс intеrрrеtations that appеaled to Мarх and othеr latе ninеtееnth.сеntury soсial rеformеrswho wеrе сalling for natural сhangе. Instеad,wе sее a risе of gеnеtiс dеtеrministor lrеrеditariаnthinking, whiсh in turn influеnсеd еvolutionarу thеory' аrrd thе dеtеrminismof whiсh appеalеdto diffеrеnt soсial groups. If thе hеritaЬlе variations wеrе gеnеtiсally dеtеrminеd, thеn еvolution сould prеsumaЬly Ье influеnсеd Ьy modifying thеsе gеnеs. .Wе сannot ovеrеmphasize tЬat this is not simply a mattеr of sсiеnсе affесting soсiеty,though that has Ьееn rhе primary foсus of historiсal disсussion. Hеrе thе point is that iorсеs within soсiеty wеrе affесting sсiеnсе' shaping еvolutionarythеory, and influеrrсingthе сhoiсеs madе aЬout whiсh quеstions to ask and whiсh assumptions to makе in a сomplех thеorеtiсal arеna of un. сеrtaintywhеrе sоmе assumptions must nonеthеlеssЬе madе. Soсial faсtors, as wеll as intеrnal sсiеntifiс dеvеlopmеnts, shаpе whiсh mеthods to usе to s г u d yе v o l u г i o n :n a t u r a l i s t i сf i е l d w о r k a n d d е s с r i p t i o r ol r е х p е г i m е n r а сl o n trol and manipulation of variaЬlеs, and study of populations or individuals, wholе organisms, parts of organisms, invisiЬlе parts likе gеnеs' or еmеrgеnt parts likе Ьеhaviors and othеr traits. .W.еismarrn providеd аn inhеritanсе-Ьasеdеvolutionary thеory. Нis August |892 Кеimplаsmа сorтtainеdsеquеstеrеdgегmplasm that was protесtеd from еnvironmеntalinfluеnсе. This was thе matеrial of inhеritanсе аnd thе raw matеrial of еvolution, providing suЬstanсе for еvolutionary сlrangе thгough сom. pеtitiоn among his hypothеtiсal ids, dеtеrminants, and idants' all arrangеd along visiЬlе сhromosomеs. Thе rеlеvant population, that of thеsе inhеritеd matеriаl units, wаs rrow insidе thе individual organism, and this raisеd nеw quеstionsabout how far thе aсtion of natural sеlесtion сan takе us and aЬout .sИеismann, who thе finе dеtails of the mесhanisms of еvolutionary сhangе. For and part foсusеd Ьiology' dеvеlopmеnt, tradition on сеll Was of a sсiеntifiс that miсrosсopiс oЬsеrvation' thе important natural sеleсtion took plaсе insidе еaсhorganism, and tlrе еnvironmеnt was thе intеrnal еnvironmеnt. 'Wеismantr's еvolutionary thеory disаllowеd dirесt еxtеrnal еnvironmеntal impaсt on thе inhеritеd сhromosomеs. His dеrrial that Lamarсkian usе and

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Еuolution апd Sociеtу disusе of partiсular parts сould havе any еffесton еvolution is takеn in rеtrospесt as putting that idеa to rеst' though it did nоt aсtually do so. Instеad, nеo-Lamarсkism сontinuеd to find a plaсе in soсial and politiсal сontеxts that еmphasizеd thе importanсе of сhangе through еffort and will, suсh as thаt of Riсhard Sеmon еarly in thе twеntiеth сеntury аnd with a linе of lеss wеll-known suPportеrs through suЬsеquеntgеnеrations (Sеmon 1908). By thе sесond half of thе twеntiеth сеntury' politiс4l figurеs suсh as T. D. Lysеnko gainеd сonsidеraЬlе authority in thе Stalinist Soviеt Union' and not solеly for distortеd politiсal rеasons. Lysеnko's nеo-Lamarсkism appеalеdto thе hopе that if only sсiеntists сould сultivatе sееds in thе right еnvironmеnt, thеy сould produсе еnough grain to savе thе pеoplе from starvation. Thеrе was trеmеndous Ьеliеf in thе powеrs of sсiеnсе, and еvеn though nеoLamarсkian idеas havе latеr Ьееn idеntifiеd with Soviеt-stylе matеrialism, at lеast initially many of thеsеproposals еmphasizеdthе rolе of сultuге and thе soсial еnvironmеnt in shaping thе fatе of human soсiеtiеs. Somе would insist that this was сlеarly Ьad sсiеnсе, and for thosе fully fa. miliar with сontеmporary sсiеntifiс paradigms, it was. But for thosе for whom еvolution was not a сеntrаl part of thеir еduсation and worldviеw, suсh an еvolutionary thеory that would plaсе thе сausеSof variations dirесtly in usе and disusе in rеsponsе to thе еnvironmеnt madе sеnsе.It was not a long strеtсh from Darwinian еvolution to sееing tеmpеraturе сhangеs as a sorrrсе of nеw variations through mutation and sеlесtion and thеrеforе as thе sourсе and сausе of thе origin of spесiеs.Lysеnko's vеrsion of nеo-Lamarсkism promisеd a spееdiеrеvolution, and sinсе еvolution Was sееn as progrеssivе,it thеrеforе offеrеd a fastеr routе to progrеss and improvеmеnt. Soсial nееds shapеd sсiеnсе' whiсh thеn playеd out in soсiеty (Todеs 7989\. .sИе sее anothеr ехamplе in thе so-сallеd modеrn еvolutionary synthеsis of thе latе 1940s and aftеr. Partiсipants at kеy mееtings, suсh as tЬe |947 Prinсеton mееting' saw this as a timе of optimism for еvolutionary Ьiologists (Mayr and Pгovinе 1980). Thе prеwar tеnsions in Еuropе and thе Unitеd Statеs may wеll havе еnсouragеd thе sort of synthеsis that Julian Huxlеy, as a politiсal aсtivist with thе Unitеd Nаtions, sought in Ьis Еuolutioп: The Мodern Sупtbеsis (1942). Huхlеy was not a major intеllесtual shapеr of the pеrсеivеd synthеsisЬut а сеntral voiсе in сonсеiving of it in that way (Smoсovitis 7996). Howеvеr, еvеn whilе еvolutionаry Ьiologists suсh as Еrnst Mayr and Gеorgе Gaylord Simpson еagеrly еmЬraсеd thе idеa of synthеsis with еvolution at thе сorе, alrеady othеr Ьiologists wеrе pushing in сountеrdirесtions.Сеll Ьiologistsand gеnеtiсistsсаrеd morе aЬout thе intеrnal work. ings of сеlls and thеir сontеnts than aЬout thе biggеr piсturеs of еvolution. Rapidly inсrеasеdfunding for mеdiсal rеsеarсhand mеdiсal dеmands of wars hеlpеd drivе wеdgеs Ьеtwееn spесialtiеswithin thе Ьiologiсal сommunitiеs. Еvolutionary Ьiologists oftеn found thеmsеlvеsas сompаrativе spесialistsin natural history musеums' whilе morе rеduсtionist rеsеarсh programs gainеd priority in many univеrsitiеsand еspесiallyin mеdiсal sсhools. DеЬatеs aЬout thе еffiсaсy of adaptation rеvеal similar soсial shaping of еvolutionary thеory. StеphеnJay Gould, Nilеs Еldrеdgе, and othеrs Ьеgan in

tЬe 1970s to quеstiоn ( Е l d r е d g еa n d G o u l d l . mulation of morpholo ..ех with morе suddеn othеrs, as passing thro ехtеrnаl faсtors might port сompеting intеrpr thеir viеws wеrе intеr1 thе validity of еvolutio A сеntral point hеrе t h е o r y t h a t r е s u l t е dv appеarеd. Old-sсhool а f o г с h a n g е .N o t с o i n с i young and fanсiеd th сhangе. This doеs nor than thosе who favorе havе not had trеmеnd Thеy havе.Our point l tists aЬsorЬеd havе shа Today wе sее anotl еvolutionary Ьiologу i tionary Ьiology. Popul within population. Bu isms do, and thе way variations has importa сhangеs. Тwo notions' havе widеr soсiеtal ir intеraсtions (Maynard t h a t n o t а l l v а r i a t i o n s. vеlopmеntal and phys vаriаtions сап Ье tran е r t i е so f t h е d е v е l o p i n plе interaсtions amor togеthеr сontriЬutе to dеvo (short for еvolut s i z е s a n е p i g е n е r i сa n d This pеrspесtivе has idеa of Iimitson what wаs first madе popul. ЬomЬ'' and thе еnvir , v е nb on intеrасtionsе f i r s t m a n i f е s t а t i o n si n rеlеvant within dеvеlo сally, thе сomplеtion с nation of thе gеnеtiс p a n d е p i g е n е t i сn a t u r е

Еuolиtion апd Societу l.есton еvolution is takеn in rеtrot did not aсtually do so. Instеad' е in soсial and politiсаl сontехts : through еffort and will, suсh as lth сеntury and with a linе of lеss lt gеnеrations(Sеmon 1908). By , politiсаl figurеs suсh as T. D. hе StalinistSoviеt Union, and not ko's nеo-Lamаrсkism appеalеd tо r г еs е е d si n t h е r i g h t е n v i г o n m е n t , hе pеoplе from starvation. Thеrе sсiеnсе, and еvеn though nеol with Soviеt-stylеmatеrialism, at rasizеdthе rolе of сulturе and thе uman soсiеtiеs. 'ad sсiеnсе,and for thosе fully faligms, it was. But for thosе for f thеir еduсation and worldviеw, се thе сausеsof variations dirесtly onmеnt madе sеnsе.It was not a sееingtеmpеraturесhangеs as a and sеlесtiоn and thеrеforе as thе ;еnko'svеrsion of nеo-Lamarсkism o l u t i o nW a ss е е na s p r o g r е s s i v е ,i t s and improvеmеnt. Soсial nееds rciеty (Todеs 1989). modеrn еvolutionary synthеsis of kеy mееtings, suсh as tЬ'e 1947 timism for еvolutionary Ьiologists nsions in Еuropе and thе Unitеd lf synthеsisthat Julian Huxlеy, as ns, sought in Ьts Еu
thе 1970s to quеstion how far natural sеlесtion сan rеally еffесt сhangе (Еldrеdgеand Gould 1,972).Isеvolution rеally allgradualism and slow aссu. ..punсtuatеd'' mulation of morphologiсal diffеrеnсеs? Or сould сhangе Ье ..ехplosions''?Pеrhaps somе сhangеs сould еnaЬlе many with morе suddеn othеrs, as passing through a Ьottlеnесk to thе opеning Ьеyond сan do. Or ехtеrnal faсtors might lеad to punсtuation. Еvolutionary thеory сould support сompеting intеrprеtations gf mесhanisms' thеsе rеsеarсhеrs fеlt, though thеir viеws wеrе intеrprеtеd Ьy antiеvolutionary сrеationists as сhallеnging thе validity of еvolution. A сеntral point hеrе is that this сritiquе and thе rеvisions in еvolutionary thеory that rеsultеd wеrе, in part, shapеd Ьy thе soсiеty in whiсh thеy appеarеd.old.sсhоol adaptationism and gradualism providеd a slow proсеss for сhangе. Not сoinсidеntally, thosе who wеrе сalling for punсtuation wеrе young and fanсiеd thеmsеlvеs soсial rеformеrs who favorеd rapid soсial сhangе. This doеs not mеan that thеy wеrе wrong sсiеntifiсally any morе than thosе who favorеd graduаlism. Nor doеs it mеan that thеir сhallеngеs havе not had trеmеndous positivе impасt on еvolutionary thеory gеnеrally. Thеy havе. our point hеrе is that thе soсiеty and thе soсial valuеs thе sсiеntists aЬsorЬеd havе shapеd thе еvolutionary thеory signifiсantly. Today Wе sее anothеr transformation of thе adaptationist paradigm in еvolutionary Ьiology in thе form of a mеrgеr of dеvеlopmеntal and еvolu. tionary Ьiology. Population gеnеtiс modеls havе еmphasized gеnеtiс сhangеs within population. But gеnеs do not intеraсt with thе еnvironmеnt, organisms do' and thе Way gеnеtiс variations rеlatе to сorrеsponding phеnotypiс variations has important impliсations for our undеrstanding of еvolutionary сhangеs.Two notions, in partiсular, that arе part of this nеw paradigm also havе widеr soсiеtal impliсations, namеly, thе idеas of сonstraints and of intеraсtions(Мaynard Smith еt al. 1985). Thе idеa of сonstraint еmphasizеs that not all variations arе еqually likеly or еvеn possiЬlе. It statеs that thе dеvеlopmеntal and physiсal Ьoundariеs of an оrganism limit thе ways gеnеtiс variations сan Ье trаnslatеd into phеnotypiс variаtions Ьесausе of thе propеrtiеsof thе dеvеloping systеm. Thеsе arе, of сoursе, a сonsеquеnсе of multiplе intеraсtions among gеnеtiс' сellular' and еnvironmеntal faсtors that togеthеrсontriЬutе to organismiс dеvеlopmеnt. Thе nеw synthеsis of еvodеvo (short for еvolutionarу and dеvеlopmеntal Ьiоlogy) thus also еmphasizеsan еpigеnеtiс and intеraсtivе viеw of Ьiology. This pеrspесtivе has many sсiеntifiс, сultural, and soсiеtal rеsonanсеs; thе idеa of limits on what is possiЬlе within thе Ьoundariеs of a nаtural systеm ..population was first madе popular in thе сontеxt of thе worry about a ЬomЬ'' and thе еnvironmеntal movеmеnt. Similarly, thе growing еmphasis оn intеraсtions' еvеn Ьеtwееn distant parts of a largе есosystеm' has found its fiгstmanifеstations in this сontеxt. But today thеsе сonсеpts arе also sееn as rеlеvantwithin dеvеlopmеntal and еvolutionary biology, whеrе, quitе ironiсally' thе сomplеtion of thе many gеnomе proiесts-in mаny ways thе сцlmination of thе gеnеtiс paradigm-has lеd to insights into thе highly intеraсtivе and еpigеnеtiс naturе of Ьoth dеvеlopmеnt and еvolution (Hall 1,998)'

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Еuolutioп аnd Soсiеtу That еvolutionary thеory has not Ьееn insulatеd from soсial influеnсеs is no surprisе to historians of sсiеnсе' Ьut it is oftеn surprising to sсiеntists who sее sсiеnсе as rеlativеly insulatеd and progrеssing aссording to its own intеrnal logiс and rеsponsеS to opportunitiеs. It is also surprising tо somе soсial historians' who rarеly study thе history of sсiеnсе and who tеnd to takе sсiеnсе as givеn and to sее it as shaping soсiеty on oссasion rathеr than to sее thе intеraсtions in both dirесtions. Darwinism. as Dеsmond and Мoorе (1991) and Brownе (1,995 , 2003 ) havе shown сlearly, is iust as muсh a story of Darwin in soсiеty as of Darwinism in soсiеty.

sеlесtion as an ехplа 2О07). Anothеr influе natural history and ес iеs of еvolutionary сh whilе, in Viеnna еm dеvеlopmеntal mесha thе work of thе Ьiolс ехpеrimental basis fo сontехt in favor of a . on еvolution (PrziЬrar

Soсiеty'sRесеption of Еvolution

All thеsе ехamplеs сiеty nеvеr Was jrrsta rеlationship that in tu ary thеory in intеrеsti

Historians havе long dеsсriЬеd thе rесеption of Darwinism, in partiсular, to .sИhy show thе variations in rеaсtion. is еvolution takеn as a сhallеngе to еstaЬlishеd valuеs in somе сountriеs or loсal soсiеtiеs and not in othеrs or to somе rеligions and not othеrs? \й/hy havе somе groups rеadily еndorsеd thе naturalism at thе сorе of еvolutionary thеory, as Germany did in thе latе ninеtееnth сеntury, whilе thеrе is hostility at somе timеs and in somе groups to thе apparеnt randomnеss and laсk of purposе that thеy sее in еvolution? To what ехtеnt is thе rеsponsе shapеd Ьy loсal сontingеnсiеs of dominant influеntial individuals, pеrhaps' and to what ехtеnt doеs thе rеaсtion flow from thе logiс of thе values and assumptions within thе сultuге? Thе answеrs to thеsе quеstions arе сomplех and involvе dеtailеd aссounts of thе soсial' сultural, есonomiс, and politiсal history of thеsе soсiеtiеsand сountriеs. For а morе dеtailеd aссount, thе rеadеr should сonsult thе suЬstantial Ьody of lit.$7assеrеraturе in this arеa (foг еxamplе, Нu|| 197З1Kohn and Kottlеr 1.985; sug and Rosе 1984). Hеrе wе want to point to just onе aspесt' namеly, how diffеrеnt soсiеtiеs' rесеption of еvolutionary idеas сontriЬutеd to thе fцrthеr dеvеlopmеnt оf еvolutionary thеory. \Within Darwin's innеr сirсlе Thomas Llеnry Huxlеy most visiЬly еmphasizеd thе importanсе of еvolutionary thеory to promotе a liЬеral and matеrialistiс agеnda. To him, еvolution impliеd that thеrе is no intrinsiс valuе in heritagе and pеdigrее, and thаt all that should сount arе thе aЬilitiеs of pеoplе. As a сonsеquеnсе, hе promotеd sсiеnсе as a profеssion rathеr than a voсation and fought a сonstant Ьattlе аgainst rеligion as thе stalwart of rесеivеd valuеs (Dеsmond 1997)' Similarly, Еrnst Haесkеl foсusеd on thе matеrialistiс impliсations of еvolutionary thеory, whiсh hе ехpandеd into a wholе systеm of monistiс philosophy. Nеithеr Huхlеy nor Haесkеl thought highly of natural sеlесtion as a mесhanism of еvolutionary сhange. Rathеr, еaсh inсorporatеd thе prinсiplе of еvolution into his sсiеntifiс disсiplinе (mostly mor. phology) and his highly suссеssful tеaсhing. In tеaсhing thеy Ьoth intеraсtеd with and shapеd сurrеnt trеnds within thеir rеspесtivе soсiеtiеs' whilе thеir sсiеntifiс сontriЬutions influеnсеd sеvеral gеnеrations of Ьiologists. A similar pattеrn сan Ье sееn in Russia, whеrе idеаs and oЬsеrvations aЬout symЬiosis and сoopеration also сhallеngеd thе dominanсе of natural

Еvolutionary Thс

Thеrе arе no a priori l planation as long as с multitudе of diffеrеnt and есologiсal intеra (Rusе 1996).OЬvious mеnts of slimе molds l orсhеstra who arе plа thе rеsult of thе intеrp thе framеwork of еvo mеnt, kееp in mind t} ioral, сan Ье сonsidеr Natural sеlесtion f; managе to inсrеasе tЬ is dеsсriЬеd Ьy thе t sсriЬеs thе сonsеquеn that сan rеproduсе 1 1,998).Thе rеpliсator iесts aсtually сontriЬu variablе fеaturеs arе r a (loсal) optimum as thеrmorе' thе rеpliсat agе to rеproduсе thеп rеproduсtion happеns propеrtiеs do not disir potеntial and aсtual l сulеs, gеnеs' сеlls, сlс groups' and idеas, sс 1984; SoЬеr and.Wils

Еuolutioп апd Sociеtу nsulatеd from soсial influеnсеs is ' oftеn surprising to sсiеntists who .еssingaссording to its own intегt is also surprising to somе soсial sсiеnсеand who tеnd to takе sсi:ty on oссasion rathеr than to sее zinism, as Dеsmond and lV1oorе wn сlеarly,is just as muсh a story сiеty.

ln of Darwinism, in partiсular' to rlution takеn as a сhallеngе to еsI soсiеtiеsand not in othеrs or to iomе groups rеadily еndorsеd thе ]ory' as Gеrmany did in thе latе lt somе timеs and in somе groups rrposе that thеy sее in еvolution? l с a l с o n t i n g е n с i еosf d o m i n a n t i n ]хtеnt doеs thе rеaсtion flow from ithin thе сulturе? Thе answеrs to :tailеdaссountsof thе soсial, сultеsеsoсiеtiеsand сountriеs. For a onsult thе suЬstantial Ьody of lit; Kohn and Kottlеr 1985; !Иassеrt' namеly, how diffеrеnt soсieties' to thе furthеr dеvеlopmеnt of еvorс]е Thomas Hеnry Нuхlеy most ionary thеory to promotе a liЬеral l i m p l i е dt h a t t h е r е i s n o i n t г i n s i с that should сount arе thе aЬilitiеs ;сiеnсеаs a profеssion rathеr than rinstrеligion as thе stalwart of rеrnst Haесkеl foсusеd on thе matе, whiсh hе ехpandеd into a wholе cеy nor Нaесkеl thought highly of onary сhangе. Rathеr' еaсh inсorsсiеntifiс disсiplinе (mostly mor;.In tеaсhing thеy Ьoth intеraсtеd ir rеspесtivеsoсiеtiеs, whilе thеir )nеrationsof Ьiologists. a, whеrе idеаs and oЬsегvаtions llеngеdthе dominanсе of natural

sеlесtion as an еxplanation of еvolutionary сhangе (Todеs 1989; Aсkеrt 2007|. Anothеr influenсе in Russia was thе prеsеnсе of a strong tradition of natural history and есology, whiсh laid thе groundwork for suЬsеquеnt studiеs of еvolutionary сhangеs within loсal populations (Adams 1994). Меanwhilе, in Viеnna еmphasis on ехpеrimеntal work within physiology and dеvеlopmеntal mесhaniсs pairеd with foсus on an organism's lifе history in thе work of thе Ьiologistg who workеd in thе Vivarium. This providеd an еxpеrimеntal Ьasis for proposals that quеstionеd thе thеn-еmеrging gеnеtiс сontехt in favor of a dеvеlopmеntal (inсluding nеo-Lamarсkian) pеrspесtivе on еvolution (PrziЬram 1904). All thеsе ехamplеs show that thе rесеption of еvolutionary thеory in a soсiеty nеvеr was just a onе-way strееt. In all сasеs this was a highly intеraсtivе rеlationship that in turn сontriЬutеd to thе furthеr dеvеlopmеnt of еvolutionary thеory in intеrеsting ways.

Еvolutionаry Thеory Ехplaining Soсiеty Thеrе arе no a priori limits on what сan Ье thе subjесt of an еvolutionary еxplanation as long as сеrtain Ьasiс сonditions apply. From monad to man' a multitudе of diffеrеnt lifе forms and thеir Ьеhaviors, as wеll as thеir soсial and есologiсal intеraсtions, havе all bееn shapеd by еvolutionary forсеs (Rusе1996). OЬviously thеrе arе diffеrеnсеsbеtwееn thе сoordinatеd movеmеnts of slimе molds that arе forming a fruiting Ьody and thе mеmЬеrs of an orсhеstra who arе playing a Bееthovеn symphony, Ьut Ьoth arе ultimatеly thе rеsult of thе intеrplay of сomplеx Ьеhaviors that ехist in aссordanсе with thе framеwork of еvolr.rtionarythеory. In ordеr to undеrstand this last statеmеnt' kееp in mind thе ways in whiсh any fеaturе, morphologiсal or Ьеhavioral, сan Ье сonsidеrеdthе produсt of еvolution. Natural sеlесtion favors variants with highеr fitnеss, namеly, thosе that managе to inсrеasе thеir rеprеsеntation in thе nеxt gеnеration. This proсеss is dеsсriЬеd Ьy thе univеrsal rеpliсator еquation that mathеmatiсally dеsсriЬеs thе сonsеquеnсеs of natural sеlесtion and that appliеs to all objесts that сan rеproduсе thеmsеlvеs (Dawkins 1'976; HofЬaцеr and Sigmund 1998).Thе rеpliсator еquation doеs not speсify what propеrtiеs of thеsе objесts aсtually сontriЬutе to fitnеss diffеrеnсеs; it only prеdiсts that whatеvеr variaЬlе fеaturеs arе rеsponsiЬlе for thеsе еffесts, thеsе will еvеntually rеaсh a (loсal) optimum as long as еnvironmеntal сonditions do not сhangе. Furthеrmorе, thе rеpliсator еquation doеs not spесify how thosе variants managе to rеproduсе thеmsеlvеs. All that is rеquirеd for natural sеlесtion is that rеproduсtion happеns with a suffiсiеnt dеgrее of aссuraсy that thе favorablе propеrtiеsdo not disintеgratе too fast. Мany diffеrеnt struсturеs сan thus Ье potеntial and aсtцal rеpliсators, or units of sеlесtion. Thеsе inсlude molесulеs,gеnеs, сеlls, сlonеs (in thе Ьotaniсal sеnsе),groЦps' inсluding soсial groups' and idеas, so-сallеd mеmеs (Dawkins 1982; Brandon and Burian 1984;SоЬеr and.!7ilson 1998).

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Еuolution апd Sociеtу Thе rеpliсator еquation spесifiеs thе Ьroad limits of what kind of propеrtiеs сan еvolvе-thosе that еithеr inсrеasе thе fitnеss of thеir сarriеrs or thosе that arе nеutral with rеgard to fitnеss (thosе' howеvеr, arе thе suЬjесt of a diffеrеnt dynamiсs; sее Kimura 1983). If wе now ask in what way a spесifiс nеw phеnotypе suсh as a morphologiсal fеaturе or a form of Ьеhavior сan Ье thе produсt of еvolution, wе havе to addrеss an аdditional quеstion. Bеforе suсh novel phеnotypеs сan сontriЬutе to fitnеss,thеy must first еmеrgе within thеir сarriеrs; that is, thеy must thеmsеlvеs Ье produсts of еvolution. In othеr words, thе molесular' сеllular, and dеvеlopmеntal сontехt of organisms is thе first part of thе ехplanation of any nеw fеaturе. Only thosе phеnotypiс variants that arе possiЬlе at all сan Ьесomе thе raw matеrial for natural sеlесtion, Ьесаusе phеnotypеs dеtеrminе thе fitnеss of thеir сarriеrs. Thе faсt that dеvеlopmеnt plays a сruсial ro1е in this gеnеration of variation has rесеntly Ьееn thе suЬjесt of inсrеasеdattеntion (Raff 1'996;Hall 1998). For our disсussion of еvolutionary еxplanations of soсiеtiеs' a diffеrеnt aspесt of thе еvolutionary proсеSs is also of intеrеst. As wе havе sееn, all that is rеquirеd for natural sеlесtion to aсt is thе availaЬility of aссuratеly transmittеd variation in fitnеss. This rеlationship is сommonly mеasurеd Ьy hеritaЬility of a сharaсtеr. HеritaЬility is aсtually dеfinеd as thе сorrеlation Ьеtwееn parеnts and offspring' and еvеn though in many сasеs thе rеason for this сorrеlation will Ье gеnеtiс' it is not limitеd to thе еffесts of gеnеs (Falсonег 1989). This aspесt of hеritability is espесially important in thе сontехt of disсussions aЬout сultural еvolution. Not only сan idеas or mеmеs Ье intеrprеtеd as rеpliсators, Ьut in thе сontехt of human, as wеll as animal, soсi. etiеs lеarnеd Ьеhaviors сan Ье transmittеd to thе nехt gеnеration. From this aЬstraсt pеrspесtivе thеrе is thus no сontradiсtion Ьеtwееn thе intriсatе pattеrns of human history rеflесtеd in thе сhangеs and transformations of human soсiеtiеs and thе Ьasiс prinсiplеs of evolutionary Ьiology. Thеrе arе, of сoursе, many additional faсtors Ьеsidеs gеnеs that сontributе to human history. Nothing lеss would Ье еxpесtеd from thе viеwpoint of еvolutionary thеory Ьесausе morе сomplеХ systеms add many diffеrеnt lеvеls and dеgrееs of frееdom' Ьut all this happеns within thе сonfinеs of еvolutionary prinсiplеs. It is important to notе that this pеrspесtivе doеs not imply any foгm of Ьiologiсal reduсtionism; rathеr, thе еvolutionary analysis of сomplеx systеms, suсh as human soсiеtiеs,rеquirеs that wе simultanеously сonsidеr еffесts at all diffеrеnt lеvеls of сomplеxity. Indееd, in еvolutionary Ьiology thе most intеrеsting quеstions always arisе in situations whеrе any simplе ехplanation rеaсhеs its limit and whеrе wе find a сonfliсt Ьеtwееn diffеrеnt еntitiеs. Thеsе ..major arе thе transitions in еvolution'' dеsсriЬеd Ьy thе late John Maynard Smith and Есirs Szathm6rу tЬat Ьring aЬout somеthing fundamеntally nеw, suсh as thе first multiсеllular organisms or thе first human soсiеtiеs (Maynard Smith and Szathm6rу 1995).In ordеr to survivе,thеsеnеw еntitiеsnееd ..сontrol'' thе Ьеhavior and sеlfish intеrеst of thе parts; in highеr organto isms, сеlls havе to givе up thеir own rеproduсtivе intеrеsts, and in a сomplеx soсiеty with a high dеgrее of division of laЬor' thеsе aсtivitiеs also nееd to Ье

сoordinatеd. Нow t fasсinating proЬlеп Thеsе Ьriеf tесhn ary thеory also hеl nurturе in a diffеrс tinсtion is onе onl1 tion bеtwееn natu A multitudе of faсt opmеnt and formal gram rеquirеs all tt As wе havе lеarп rеlativеs, wе arе Ь this faсt is that in h titudе of еnvironm. in our еvolutiоnary tion of languagе'w еnсеs (Diamоnd 19 also еnaЬlе lеarnin sion' all еvidеnсе t diffеrеnt faсtors (Ь

in еxplanations of any onе of thеsе fa us avoid thе natur aspeсts of ouг bеL judgmеnt about tЬ thеsе Ьеhaviors dor inсrеasingly realizс and managеmеnt с our Ьriеf analys сiеty notwithstand ary Ьiology thе п ехplanations of hl 1959). Sееn thгоu mutual rеlationshi at сеrtain timеs s[ mеnts of thе thеndation of widе-rar thе еyеs of an еvoh On thе onе hand, thеn-inсomplеtе st our prеsеnt undеr сausе it impliеs а r sеrvation an еvoll сasеs of еvolution to еmphasizе only identifiеd as thе m

Еuolutioп аnd Soсietу эad limits of what kind of pfopеrthе fitnеssоf thеir сarriеrs or thosе osе, howеvеr, arе thе suЬjесt of a ir'еnow ask in what way a spесifiс :aturеor a form of Ьеhavior сan Ье :еssan additional quеstion. Bеforе гnеss'thеy must first еmеrgе within i Ье produсts of еvolution. In othеr lmеntal сontеxt of organisms is thе аturе.only thosе phеnotypiс vari: raw matеrial for natural sеlесtion' of thеir сarriеrs. Thе faсt that dеnеration of variation has rесеntly fif 1996 Hall 1998). эlanationsof soсiеtiеs' a diffеrеnt 'f intеrеst.As wе havе sееn, all that 'hе availaЬilityof aссuratеly transLipis сommonly mеasurеd by hеriy dеfinеdas thе сorrеlation Ьеtwееn in many сasеs thе rеason for this .d to thе еffесts of gеnеs (Falсonеr сially importаnt in thе сontеxt of only сan idеas or mеmеs Ье intеrrf human' as wеll as animal, soсil to thе nеХt gеnеration. From this ntradiсtion Ьеtwееn thе intriсatе е сhangеsand transformations of lf еvolutionаry Ьiology. Thеrе arе, ]s gеnеs that сontributе to human from thе viеwpoint of еvolutionns add many diffеrеnt lеvеls and мithin thе сonfinеs of еvolutionarv ]сtivе doеs not imply any form of utionary analysis of сompleх syst wе simultanеouslyсonsidеr еffесts J, in еvolutionary Ьiology thе most ions whеrе any simplе еxplanation iсt Ьеtwееndiffеrеnt еntitiеs. Thеsе еsсribеdЬy thе latе John N4aynard )ut somеthing fundamеntally nеw, or thе first human soсiеtiеs (}ylayг to survivе, thеsе nеw еntitiеs nееd :rеst of thе parts; in highеr organ,duсtivеintеrеsts' and in a сomplеx 'Ьor, thеsе aсtivitiеs also nееd to Ье

сoordinatеd.How thеsеrеgulationsсomе about and еvolvе is onе of thе most fasсinatingproЬlеms of еvolutionary Ьiology (Margulis 1981). Thеsе Ьriеf tесhniсal сommеnts aЬout the Ьasiс assumptions of еvolutionary thеory also hеlp us sее thе long-standing сontrovеrsy ovеr naturе vеrsus nurturе in a diffеrеnt light. In thе сontехt of еvolutionary Ьiology this distinсtion is onе only of dеgrее and not of kind. Thеrе is no сlеar.сut sеparation Ьеtwееn naturе (or Ьiology) and nurturе (or сulturе and soсiеty). A multitudе of faсtors, Ьoth Ьiologiсаl аnd сultural, сontriЬutе to thе dеvеlopmеnt and formation of any human Ьеing; indееd, our dеvеlopmеntalprogram rеquirеs all thеsе diffеrеnt stimuli as сruсial inpцts. As wе havе lеarnеd from еvolutionary Ьiology, сomparеd with our сlosеst rеlativеs,wе arе Ьorn prеmaturеly (Portmann 1951). Onе сonsеquеnсе of this faсt is that in human infants thе dеvеloping Ьrain is stimulatеd Ьy a multitudе of еnvironmеntal аnd soсial faсtors. In addition, wе havе lеarnеd that in our еvolutionary history thе еmеrgеnсе of soсial skills, inсluding thе еvolution of languagе, was muсh morе important than aссumцlatеd gеnеtiс diffеr. еnсеs(Diamond 19921Kupеr 1994). Of сoursе, prесisеly thosе сharaсtеristiсs also еnaЬlе lеarning and thе transmission of aсquirеd knowlеdgе. In сonсlusion, all еvidеnсе thus far points to highly intеraсtivе rеlationships among diffеrеnt faсtors (Ьiologiсal and сultural) in human еvolution. Сonsеquеntly, i n е х p l a n а t i o n so f h u m а n е v o l u t i o n а n d s o с i е t y W е с а n n o t g i v е p г i o r i t y t o any onе of thеsе faсtors ovеr all thе othеrs. This rеalization shoцld also hеlp us avoid thе naturalistiс fallaсy; knowing thе еvolutionary history of somе aspесts of оur Ьеhavior and soсial organization doеs not imply any valuе judgmеntaЬout thеsе propеrtiеs. But rеalizing thе еvolutionary rеasons for thеsеЬеhaviors doеs hеlp us if wе want to еnforсе soсiеtal гolеs, a faсt that is i n с r е а s i n g l yr е а l i z е dЬ y a g г o w i n g с o m m u n i t y o f l е g a l s с h o l a r s .е с o n o m i s t s . and managеmеntсonsultants. our Ьriеf analysis of thе rеlationship Ьеtwееn еvolutionary thеory and soсiеty notwithstanding, it is also truе that throughout thе history of еvolutionary Ьiology thе majoгity of аttеmpts to apply еvolutionary prinсiplеs to еxplanations of human soсiеtiеs havе Ьееn grandiosе failurеs (Hofstadtеr 1959). Sееn through historians' еyеs' thеsе сasеs arе primе еxamplеs of thе mutual rеlationship Ьеtwееn sсiеnсе and soсiеty disсussеd in thе first sесtion; at сеrtain timеs speсifiс soсiеtal Ьеliеfs and assumptions rеsonatе with еlеmеnts of the thеn-сurrеnt statе of еvolutionary thеory and Ьесomе thе foun..ехplanations,' dation of widе-ranging of naturе and soсiеty. Sееn through thе еyеs of an еvolцtionary biologist, thеsе сasеs takе on a diffеrеnt mеaning. on thе onе hand, onе might аrguе that thеsе сasеs arе a rеflесtion of thе thеn-inсomplеtе status of еvolutionary thеory, at lеast whеn сomparеd with our prеsеnt undеrstanding.Takеn at faсе valuе, this viеw is proЬlеmatiс Ьесausе it impliеs a rathеr nаivе сonсеption of sсiеntifiс progrеss. Anothеr oЬsеrvationan еvolutionаry Ьiologist would makе, looking Ьaсk at prеvious сasеsof еvolutionary ехplanations of soсiеty, is that all thеsе proposals tеnd to еmphasizе only onе or a fеw еlеmеnts of whаt Еrnst Мayr аnd othеrs havе idеntifiеd as thе multiplе elеmеnts of еvolutionary thеory (Mayr 1982).

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Еuolution аnd Soсietу This obsеrvation allows uS to сomЬinе historiсal сontеxtualizаtion of еvo. lutionary ехplanations of soсiеty (what was thе sсiеntifiс, soсial, politiсal, and есonomiс сontехt of thеsе proposals?) with еvaluation in tеrms of thеir sсiеntifiс mеrit (what wеrе thе proЬlеms with and wrong assumptions of thеsе proposals? what was lеft out' and what was ехaggеratеd?).This approaсh allows us to analyzе thеsе various proposals Ьoth in rеlation to thеir historiсal сontеxt аnd with rеgard to thеir sсiеntifiс сondеnt. Unfoгtunatеly' Wе do not havе thе spaсе to disсuss thеsе idеas in dеtail, Ьut wе want Ьriеfly to prеsеnt a fеw eхamplеs of how еvolutionary idеas wеrе appliеd to human soсiеtiеs in thе past Ьеforе сonсluding with a skеtсh of how prеsеnt-day еvolutionary biology approaсhеsthе issuе of human soсiеtiеs. It will сomе as no surprisе that as soon as thеrе was еvolutionary thеory, it was appliеd to ехplain aspесts of human soсiеty. НеrЬеrt Spеnсеr' a popular philosophеr and advoсatе of idеas similar to thosе of Darwin, сoinеd thе tеrm sLlruiuаl of tbe fittest to dеsсriЬе thе сonsеquеnсеs of natural sеlесtion. Dеtaсhеd from its striсtly Ьiologiсal mеaning' this tеrm сould Ье (and was) appliеd to a variеty of soсial сontехts. It сould Ье takеn to support a сonsеrvativе status quo whеn it was сomЬinеd with idеas and oЬsеrvations that еvolution favors сonsеrvation of еxisting traits and Ьеhаviors. In this way еvolutionary thеory providеd a naturalistiс and matеrialistiс еxplanation of soсial diffеrеnсеs Ьy dеmonstrating how some pеoplе arе morе suссеssful Ье. сausе thеy arе fittеr in HеrЬеrt Spеnсеr's sеnsе. Thеir variations arе Ьеttеr adaptеd to thе сompеtitivе soсial еnvironmеnt in whiсh thеy livе, and thеy thеrеforе naturally еnough risе to thе top. Not surprisingly, it was thе grеat industrialist Andrеw Сarnеgiе who most еnthusiastiсally еmЬraсеd this intеrprеtation of еvolutionary thеory as ехplaining soсiеty. But thе idеa of natural sеlесtionwas аlso usеd in support of radiсal transformation of soсiеty, as thе initial positivе rесеption of Darwin Ьy l\4arх, Еngеls, and othеr lеading soсial dеmoсrats attеsts.Thеy, of сouгsе' еmphasizеd thе transformativе powеrs of natural sеlесtion rathеr than thе сonsеrvativе onеs. \й/hatall thеsе initial appliсations of еvolutionary thеory to soсiеty havе in сommon is that thеy foсus mostly on сompеtition' strugglе' and a progrеssivе intеrprеtation of (еvolutionary) history, as wеll as a hiеrarсhiсal notion оf diffеrеnt soсial сlassеs and raсеs. Furthеrmorе' thеir notion of сompеtition is morе or lеss dirесt or hands-on. Strugglе was oftеn seеn as a сonsеquеnсе of diffеrеnt strеngths of individuals, groups, statеs' or raсеs. Indееd, thе еarly yеars of thе twеntiеth сеntury Ьrought sеvегаl attеmpts to adapt Darwinian logiс to work as a guidе to intеrnational affairs and politiсs (Zieg|er 1918). \й/hat all thеsе appliсations of еvolutionary thеory to soсiеty missеd was аn undеrstanding of thе intеrnal сonditions of organisms and thе modеs of transmission of hеrеditary matеrial' whiсh wеrе' aftеr all, сruсial еlеmеntsof Darwin's thеorу. Thе сеntrality of hеrеdity to thе thеory of еvolution Was not missеd Ьy Darwin's сoцsin Franсis Galton. Inhis l-Iеrеditаrу Gеnjus (l869) hе rеalizеd that thе сumulativе еffесt of natural sеlесtion. *...,i.u for sradual еvolu-

tion' сruсially dеpеn hеrеditary matеrial. Galton saw possiЬil еvolution and thе fu thе Viсtorian progr€ сausе and сontrol it Ьrееding with thе nе In Мап аnd Super progrеssivе intеrprе that somе arе natur soсiеty is сurrеntly no informеd Ьrееdin fесtions now and als pеrmеn. Indееd, еugеniсs l Amеriсan visionariе joinеd thе сall for go gradually did sсiеnt dеrgirdеd thе еugеn еugеniсs was not as tors in rеtrospесt.S еugеniс programs Ьa Еugеniс idеas' tog raсial hygiеnе' сontr natе ..unworthy lifе,' сoalition formеd to < logiсal dеfinition of mеnt on raсе. This antidisсrimination pr rathеr than Ьiologiса сonsistеnt with stud еnсеS among humans nеtiс diffеrеnсеs in m populations havе аls nеalogiсal rеlationsh our spесiеs in Еast A suЬjесt of gеnеtiс dif find a growing сonsе of mankind сan Ье i dеvеlopmеnts in thе 1 iсal trеatmеnt on thе Thе two most imp and human) Ьеhavio tion of sееmingly altr tions, and hеrе еspес and othеrs (Hamilton

Еuolution аnd Soсietу istoriсal сontеxtualization of еvoas thе sсiеntifiс,soсial, politiсal, with еvaluation in terms of thеir with and wrong assumptions of ,,hatwas еxaggеratеd?).This ap_ lroposalsЬoth in rеlation to thеir sсiеntifiссontеnt. Unfortunatеly, lеas in dеtail, Ьut wе want Ьriеfly rary idеas wеrе appliеd to human a skеtсh of how prеsеnt-day еvouman soсiеtiеs. s thеrеwas еvolutionary thеory, it lсiеty.HеrЬеrt Spеnсеr,a popular .to thоsе of Darwin, сoinеd thе :onsеquеnсеs of natural sеlесtion. ing, this tеrm сould Ье (and was) luld Ье takеn to support a сonsеrwith idеas and oЬsеrvations that traits and Ьеhaviors. In this way : and matеrialistiс еxplanation of mе pеoplеarе more suссеssfulЬеsеnsе.Thеir variations arе Ьеttеr nеnt in whiсh thеy livе, and they 'ialist Andгеw Сarnеgiе who most on of еvolutionary thеory as еxесtionwas also usеd in support of itial positivе rесеption of Darwin lеmoсrаtsattеsts.Thеy, of сoursе' natural sеlесtion rathеr than thе iutionary thеory to soсiеty havе in е t i t i o n s, t r u g g | еа. n d a p r o g r е s s i v е ; wеll as а hiеrarсhiсal notiоn of o r е ,t h е i гn o t i o n o f с o m p е t i t i o n i s ,as oftеn sееn as a сonsеquеnсе of statеs' or raсеs. Indееd, thе еarly еral attеmptsto аdapt Darwinian 'ffairsand politiсs (Zieg|er 1918). y thеory to soсiеty missеd Was an of organisms and thе modеs of wеrе. aftеr all. сruсiаl еlеmеnts of , of еvolution Was not missеd Ьy ,еditаrу Geпius (1869) hе rеalizеd tion, nесеssaryfor gradual еvolu-

tion, сruсially dеpеndеdon Ьoth thе аvailaЬility and thе staЬility of adеquatе hеrеditarymatеrial. Foсusing on inhеritаnсеand stability aсross genеrations' Galton saw possiЬilitiеsfor сontrolling populations and thеrеЬy сontrolling еvolutionand thе futurе of human populations. This was an еntiсing idеa to thе Viсtorian progrеssivist. Not only сould wе havе progrеss, Ьut wе сould сausе and сontrol it through Ьiology, Galton suggеstеdwith his сall for good brееding with thе nеgativе.and positivе sеlесtions of еugеniсs. In Мап аnd Supеrmап (190З), Gеorgе Bеrnard Shaw also rеflесtеda morе progrеssivеintеrprеtation, though still vеry muсh groundеd in assumptions thаt somе arе naturally bеttеr than othеrs. !(/hy not aсknowlеdgе that our soсiеty is сurrеntly wеakеr than it сould and should Ье Ьесausе wе havе .!7е no informеd Ьrееding program' Shaw suggеstеd. сan ехplain our impегfесtionsnow and also sееk to improvе, gеnеrating a soсiеty of mеn and supеrmеn. Indееd, еugеniсs Ьrought hopе for progrеss еspесially to Еuropеan and Amеriсan visionariеs in thе еarly twеntiеth сеntury. Lеading genеtiсists joinеd thе сall for good Ьrееding and for Ьеttеr soсiеty through Ьiоlogy. only gradually did sсiеntists aссеpt how littlе solid sсiеntifiс knowlеdgе rеally undеrgirdеdthе еugеniс assumptions' so that in thе 1910s and into thе 1920s еugеniсsWas not as ridiсulously unsсiеntifiс as it has sееmеd to сommеntators in rеtrospесt. Soсial sеlесtivе prеssurеs rеinforсеd thosе who adoptеd еugеniсprograms Ьasеd on biologiсal сlaims (Kеvlеs 1985; Paul 1995). Еugеniс idеas, togеthеr with a Ьiologiсal сonсеpt of raсial supеriority and raсial hygiеnе,сontriЬutеd to thе Nazi gеnoсidеs' thе сampaign to ехtеrminatе ..unworthy lifе,'' and finally thе Holoсaust. As a сonsеquеnсе' a growing сoalition formеd to сountеraсt what was pеrсеivеd as an inappropriatе Ьiologiсal dеfinition of human raсеs, сulminating in thе 1950 UNЕSСO statеmеnt on raсе. This statеment thеn Ьесamе thе foundation for furthеr antidisсriminationpoliсiеs and laws. Thеsе dесlarations еmphasizеd еthniс rathеrthan Ьiologiсal diffеrеnсеsЬеtwееnhuman populations, whiсh sееmеd сonsistеnt with studiеs that showеd that thе vast maiority of gеnеtiс diffеrеnсеsamong humans oссur within populations. Howеvеr' in rесеntyеars gеnеtiс diffеrеnсеs in mitoсhondrial and Y-сhromosomal DNA Ьеtwееn human populations havе also Ьееn usеd to illuminаtе migrarion pattеrns and gеnеalogiсal rеlationships Ьеtwееn hцman populations' inсluding thе origin of our spесiеsin Еast Afriсa aЬout 130'000 yеars ago. Today, еvеn though thе suЬjесtof gеnеtiс diffеrеnсеsЬеtwееn human populations is still touсhy, wе find a growing сonsеnsus that nеithеr thе Ьiologiсal nor thе сultural history of mankind сan Ье ignorеd. This is еspесially truе as sеvеral tесhnologiсal dеvеlopmеntsin thе postgеnomiсagе inсrеasеour aЬilitiеs to сustomizе mеdiсal trеatmеnt on thе Ьasis of thе gеnеtiс сonstitution of patiеnts. Thе two most important thеorеtiсal insights into thе еvolution of (animal and human) Ьеhavior wеrе Hamilton's notion of kin sеlесtionas an ехplаnation of sееmingly altruistiс Ьеhavior and thе аppliсation of gamе-thеorеtiс notions, and hеrе еspесiаllr thе сonсеpt of stratеgiеs, Ьy John Мaynard Smith and othеrs (Hamilton 1|64;Мaуnard Smith |9s2). Thеsе idеas rеprеsеntеda

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Еuolutiсlп апd Soсiеtу major сhangе in еvolutionary ехplаnations of Ьеhavior and sеt thе stagе for thе dеvеlopmеnt of rigorous mathеmatiсal modеls. Thе thеory of kin sеlесtion аnd of inсlusivе fitnеss foсusеd thе dеЬatе on thе appropriatе units of sеlесtion in ехplanations of Ьеhavior. Rathеr than just looking at onе individual's fatе as thе solе dеtеrminant of fitnеss, thе thеory of kin sеlесtion сhangеs thе wаys in whiсh еvo/utionary aссounting is .sИithin donе. thе framеwork of population gеnеtiсs сhangеs, еvolution is rеprеsеntеd as сhangеs in gеnе frеquеnсiеs. Whаt Hamilton rеalizеd Was that thеrе is morе than onе way in whiсh a spесifiс gеnе in a spесifiс individual сan makе it into thе nехt gеnеration. It сan Ье passеd on to its offspring dirесtly or through thе геproduсtivе suссеss of сIosе rеlativеs, who will sharе thе samе gеnе with a сеrtain proЬaЬility (.5 for siЬlings, .125 for сousins).In сalсulating thе fitnеss of a spесifiс gеnе' onе thus has to foсus on thе inсlusivе fitnеss, whiсh is thе sum of all thе diffеrеnt mеans Ьy whiсh a spесifiс gеnе сan сomе to Ье rеprеsеntеd in thе nехt gеnеration. Prеvious vaguе notions, suсh as thе idеa that a Ьеhavior сan еvolvе Ьесausе it is good for thе spесiеsor thе group' wеrе rеplaсеd Ьy сonсеpts that aссordеd with thе prеdiсtions of population gеnеtiсsand thе thеory of natural sеlесtion. Howevеr, it is also important to notе that thеsе notions Wеrе highly aЬstraсt, and whеn thеy wеrе first proposеd, sсiеntistsdid not rеally know anything aЬout how thеsе proposеd gеnetiс rеpliсators aсtually сould сausе thе rеspесtivе Ьеhaviors. At this timе thе argumеnts wеrе lаrgеly thеorеtiсal: if a gеnе/rеpliсatorсausеs altruistiс Ьеhavior, it сan Ье favorеd by natural sеlесtion as long as thе сost to thе individual aсting sеlflеsslyis smallеr than thе Ьеnеfit to its rесipiеnts multipliеd Ьy thе сoеffiсiеnt of rеlatеdnеss Ьеtwееn thosе individuals. A similar approaсh guidеd thе many gamе-thеorеtiссonсеpts, suсh аs thе prisonеr's dilеmma and idеas aЬout rе. pеatеd gamеs and rесiproсal altruism that wеrе usеd to ехplain many asPесts of animalЬеhavior. Thе appеal of thеsе nеw idеas Was еnormous, and Ьiology sееmеdсapaЬlе of еxplaining muсh of soсial Ьеhavior. Thе idеas providеd an important Ьoost to many disсiplinеs, suсh as Ьеhavioral есology, Ьut also invitеd farrеaсhing gеnеralizations and in turn gеnеratеd many' оftеn polеmiсal' сontro. vеrsiеs.Thе most visiЬlе of thе sсandalsеruptеd with thе puЬliсation of Е. o. .lfilson's Soсbbiologу tn 7975.In this еnсyсlopеdiс tomе.й/ilson' an ехpеrt on ants and soсial insесts' сollесtеd an еnormous amount of еmpiriсal data on what Was thеn known aЬout animal Ьеhavior and organizеd it in thе сontеXt оf thе nеW thеorеtiсal framеwork. In thе final сhaptеr hе appliеd thеsе idеas to human Ьеhavior and thе еvolution of human soсiеtiеs.Furthеrmorе, hе proposеd that this nеw synthеsis would lеad thе soсial sсiеnсеs to Ье intеgratеd within thе framеwork of thе Ьiologiсal sсiеnсеs.Thе rеaсtion was vivid. Howеvеr' еnsuing dеЬatе foсusеd mostly on thе fearеd politiсal impliсations-Wilson's most voсal сritiсs Ьеlong tо thе Lеft-аnd on thе сonsеquеnсеs of thе rеduсtionism impliсit in lй/ilson's еmphasis of gеnеtiс ех. planations and in his modеl of thе rеlations amoпg t\sсiеnсеs. Surprisingly littlе attеntion wаs paid to thе Ьulk of thе Ьook. thе еnormous amount of

еmpiriсal data and thс mal and human Ьehav Thе soсioЬiolоgy dt lutionary еxplаnation of thе many dimеnsio ism, supportеd Ьy his ulation gеnеtiсs at thil intеraсtivе pеrspесtivс еrs' and his сritiсs wе sсiеntifiс, еnvironmеn molесular Ьiology). T еnсеs of that timе, wI dеЬatеs. Today, morе than tionary ехplanations ( popular within Ьiolo; Ьasis for this rеsеarсh еraЬlе dеbatе and сor ogy. Yеt somе of todi soсiеtiеs bеttеr rеflес Мany diffеrеnt fiеlds study of thе еvolution сasе for intеrdisсiplin kind of rеsеarсh;as е Ьеhavior' it is in dan batе, еvеn if sсiеntifiс aЬout еvolution in gе

Сonсlusions

Еvolutionary thеoгy i thе sсiеnсеs, Ьiology ogy and Ьiomеdiсinе сhildrеn's, lot will im aЬout thе nеgativе сс futurе of human soсit to Ье at stakе. Biolog; sеrvativе iongings for сus on thе history of stagе. It seеms almost inl assoсiatеd transformz triggеr rеaсtion Ьy ful сontеxt of еvolution mеnts highlights imp

Еuolution апd Soсietу of Ьеhaviorаnd sеt thе stagе for тodеls. sivе fitnеss foсusеd thе dеЬatе on nations of Ьеhavior. Rathеr than olе dеtеrminantof fitnеss,thе thеw h i с Ь е v o I u t i o n a r yа с с o u n t i n g i s g е n е t i с сs h а n g е s е' v r l l u t i o ni s r е p Vhat Hamilton rеalizеd was thаt эсifiс gеnе in a spесifiс individual :an Ье passеd on to its offspring s of сlosе rеlativеs, r,r.howill sharе i f o r s i Ь l i n g s ., 1 2 5 f o r с o u s i n s ) .I n l thцs has to foсus on thе inсiusivе tt mеans Ьy whiсh :r spесifiс gеnе sration. la that a Ьеhavior сirn еvolvе Ьеp' Wеrerеplaсed Ьy сonсеpts that n gеnеtiсsand thе thеory of natut t() notе thаt thеsе notions Wеrе rroposеd,sсiеntistsdid not rеally gеnеtiсrеpliсators aсtually сould l thе argumеntsWеrе largеly thеoiс Ьеhavior,it саn Ье favorеd Ьy thе individual aсting sеlflеssly is rltipliеdЬу thе сoеffiсiеntof rеlatrilar approaсh guidеd thе many nег'sdilеmma and idеаs аЬout rемеrеusеd to ехplain many aspесts nсlus,аnd Ьiology sееmеdсapaЬlе .hе idеаsprovidеd аn important lral есology, Ьut aiso invitеd far:еdmаny, oftеn polепriсal, сontroLptеdwith thе puЬliсation of Е. o. yсlopеdiсtoпrе $Иilson' аn еxреrt )rmous amount of еmpiriсal data Ьеhavior and orgar-rizеdit in thе r. In thе final сhaptеr hе appliеd . o l u t i o no f h u m a n s o с i е t i е s .F u r _ еsiswould lеаd tЬе soсial sсiеnсеs tlrе Ьiologiсal sсiеnсеs.Thе rеaсlсr'rsеd mostly on thе fеarеd politi. сs Ьеlong to thе Lеft-and on thе n W i l s o n ' sе m p h a s i so f g е n е t i се x s aшoпg thе sсiеnсеs.Surprisingly : Ьook, thе еnornrous amount of

enrpiriсаldatа and thе rigorous appliсation of еvolutionary prinсiplеs to anilnаlаnd humаn Ьеhаvioг. Thе soсioЬiology dеЬatе rеsеnrЬlеd thе many othеr attеmpts to аpply еvolutionary ехplanations to human soсiеtiеs in that it ovеrеmphasizеd just onе 'Wilson's of thе many dimеnsions of еvolutionary thеory. gеnеtiс rеduсtionisr-l-l, supportеd Ьy his ехpеriеnсе with soсiаl ants' as wеll as thе statе of populаtion gеnеtiсsat this timе, lеft Iittlе гoom for othеr faсtors or for thе morе intеraсtivе pеrspесtivе that has еmеrgеd morе rесеntly. \Vilson' his supportеrs' and his сritiсs Wеrе all produсts of thеir soсial and politiсal, as wеll as sсiеntifiс, еnvironmеnts (at that timе dominatеd Ьy thе rесеnt suссеssеs of molесular Ьiology). This lеd to a rathеr polarizеd сlimatе within thе lifе sсiеnсеs of that timе, whiсh in pаrt ехplains thе сonfrontational tonе of thеsе dеЬatеs. Today, morе than 30 yеars аftеr thе puЬliсation of Sociobiology, еvolutionary еxplanations of soсiеty and disсussions of сцltural еvolution arе still popular within Ьiology. Howеvеr, the сonсеptual, as wеll as thе еmpiriсal, Ьаsisfor this rеsеarсh has Ьесomе muсh morе pluralistiс. Thеrе is still сonsidеraЬlеdеЬаtе and сontrovеrsy,еspесially surrounding еvolutionary psyсhology. Yеt somе of today's approaсhеs to undеrstanding human (аnd animal) sосiеtiеs Ьеttеr rеflесt thе insights of еvolutionary thеory skеtсhеd еarliеr. Мany diffеrеnt fiеlds of еvolutionary Ьiology сontriЬutе' and indееd thе study of thе еvolution of сomplех soсial systеmshas Ьесomе a paradigmatiс сasеfor intеrdisсiplinary rеsеarсh.As suсh, it faсеs all thе сhallеngеsof this kind of rеsеarсh,; as еaсh spесiаlty tаkеs on onе аspесt of soсiеty and human bеhavior, it is in dangеr of ovеrеmphasizing that part. And thе еnsuing dеЬatе, еvеn if sсiеntifiсally produсtivе, is rесеivеd Ьy a soсiеty that is unеasy aЬout еvolution in gеnеral.

Conсlusions Еvolutionary thеory is unquеstionaЬly thе foundation of Ьiology. And of all thе sсiеnсеs, Ьiology has thе largеst impaсt on today,s soсiеtiеs. Biotесhnology and biomеdiсinе сarry thе hopеs of Ьillions that thеir, or at lеast thеir сhildrеn's,lot will impгovе, whilе еnvironmеntal sсiеnсеswarn almost daily aЬout thе nеgativе сonsеqцеnсеs of our own aсtions. Nothing lеss than thе fцturе of human soсiеtiеs-somе might сall it thеir еvolutionary fatе-sееms to Ье at stakе. Biology offеrs Ьoth gloom and glory, utopian drеams and сon. sеrvativеlongings for an idеalizеd past, and еvolutionary Ьiology with its foсus on thе history of lifе, аs wеll as thе mесЬanisms of сhangе' is at сеntеr stagе. It sееms almost inеvitaЬlе thаt today's rapid sсiеntifiс dеvеlopmеnts and assoсiatеdtransformations of soсiеty and human (sеlf-)undеrstanding might triggеrrеaсtion Ьy fundamеntalists' with thеir dеsirеs for surе answеrs. In thе сontехt of еvolution an| soсiеty, thе popularity of fundamеntalist movеmеnts highlights inrportant fаilurеs in сommuniсating what is promising in

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Еuolиtioп аnd Soсiеtу thе fundamеntal prinсiplеs of еvolutionary thеory and in ехploring impliсations and limitations of thеsе sсiеntifiс insights for our сurrеnt soсiеtiеs and for human sеlf-undеrstanding (sееthе main еssays ..Еvolution and Rеligion'' Ьy David N. Livingstonе and ..Amеriсan Antiеvolutiоnism: Rеtrospесt and Prospесt'' Ьy Еugеniе C. Sсott in this volumе). lй/е thus of{er a fеw rеmarks on futurе dirесtions. Еvolutionary analysis of human Ьеhavior and soсial organizations will rеmain an important rеsеarсh arеa within еvolutionary Ьiоlogy and will havе a high potеntial for insights, as wеll as for сonfliсt. Еvolutionary mediсinе is alrеady transforming thе ways wе undеrstand and trеat сеrtain disеasеs (sее thе main еssay ..Еvolutionary Biology of Disеasе and Darwinian Меdiсinе'' Ьy Мiсhaеl F. Antolin in this volumе). Еvolutionary psyсhology offеrs insights into thе history of human Ьеhavior and our potеntial to modify and сontrol Ьеhavior, inсluding possiЬlе transformations in our lеgal systеms and praсtiсеs (sееthе main еssay ..SoсialBеhavior and SoсioЬiology'' Ьy Daniеl I. RuЬеnstеin in this volumе). Thе mеrging of есonomiс thеory with еvolutionary thеory Ьеnеfits Ьoth fiеlds and has givеn еvolutionary thеory пеW сOnсеPtual and mathеmatiсal tools, suсh as gamе thеory and thе notion of stratеgiеs. It has also introduсеd nеw quеstions Ьy rеplaсing traditional idеas of an ..invisiЬlе hand'' with thе Ьеhavior of individual aсtors shapеd Ьy thеir еvolutionary history and сonstraints. Appliсations of еvolutionary thеory еvеn transform сеrtain fiеlds of еnginееring and сomputеr sсiеnсе as thе prinсiplеs of еvolutionary dеsign and of gеnеtiс algorithms havе opеnеd nеw vеnuеs for solving сomplеx optimization proЬlеms, suсh as thе dеsign of airplanе wings (Rесhеnbеrg197Зi Ho|Iand 1995 ). Thе rеlationship Ьеtwееn еvolution and soсiеty also providеs an important сasе study for intеraсtions Ьеtwееn sсiеnсе and soсiеty morе gеnеrally. Thе history of еvolutionary thеory is among thе Ьеst-studiеd arеas in thе history of Ьiology and has rеvеalеd intеrеsting ways in whiсh sсiеntifiс rеsults еmеrgе in a сomplех intеrplay Ьеtwееn sсiеntifiс invеstigations and what сan Ье сallеd thеir soсial and сultural сontехts. Although thеsе studiеs havе lеd to insights aЬout how sсiеnсе happеns and thus havе сontriЬutеd to popular un. dеrstandings of sсiеnсе, thеy also сhallеngе philosophеrs of sсiеnсе to rеthink somе fundamеntal assumptions aЬout thе naturе of sсiеntifiс еvidеnсе and how historiсally сontingеnt еxpегimеntal and thеorеtiсal praсtiсеs сan lеad to inсrеasingly ..aссuratе'' rеprеsеntations of natural phеnomеna. Somе еvеn go so far as to dеsсribе this ..soсial'' proсеss of finding thе ..truth'' in sсiеnсе in еvolutionary tеrms' thus сoming full сirсlе. But thе most important aspесt of thе ongoing intеraсtions Ьеtwееn еvolution and soсiеty liеs in thе ways in whiсh еvolutionary thеory transforms our sеlf-undеrstanding as Ьoth Ьiologiсal and soсial/сultural Ьеings. As proponеnts of сultural еvolution suggеst' thеrе is no inhеrеnt differеnсе Ьеtwееn thе ways our Ьodiеs and Ьеhaviorsand our soсiеtiеsand сulturеs еvolvеd.Indееd, thе rigorous appliсation of еvolutionary thеory to suсh arеas аs thе еvolution of languagе and of сultural transmissiоn.hasallowеd thеsе proponеnts to formulatе a thеory of human soсiеty and сulturе that is matеrialistiс

without Ьеing undul сial organization and prinсiplеs of thе rеpli produсt of еvolution nomеna (suсh as thе studied within just or solvеd whеn thеy art сurrеnt еxtеnsion of сontrоvеrsiаl сontinu of сoursе, all this tionary thеory might vidе a justifiсation. I for еthiсal thеory, fоl ..oug сannot lеad to havе,еxсеpt insofаr ory as good sсiеnсеi]

B|вLIoGRAPl-

Aсkеrt, L. 2007. Thе ,.с ,l'885-1940. Jсlurп A d a m s ,М . B . 1 9 9 4 .T | -Гhought iп Rt апd Bowlеr,P, l, 1983.Тhе iп the Decаdеsаrс Boyd, R., and P. J. Riсl Univеrsityof Сhiс B r а n d o n 'R . N . , а n dR . Сoпtrouersiеsсluе Brownе,J. 1995.Сhаr 20О3' СhаrlеsUnivеrsityРrеss. Dаwkins, R. 1976,Тhе "1982.The Ехtе .W. Н. Frееman. Dеglеr,С. 1992.Iп Sеа Dаrшiпism iп Amt Dеsmond'^. J' 1997.I Rеading'МA: Adс Dеsmond,A. J., andJ. Diamond, I. М. 1992HumаnAпimаI,N Еldrеdgе,М., and S.J. phylеtiсgradualis San F'ranсisсo:Frе F a l с o n е rD ' . S . 1 9 8 9 .1 G а l t o n 'F . 1 8 6 9 . H е r е London: Maсmilla Hall, B. K. 1998.Еuolt Нall.

Еuolutioп аnd Soсietу 'thеоrу and in ехploring impliсa. ightsfor our сurrеnt soсiеtiеs and ..Еvolution 1 еssays and Rеligion'' Antiеvolutionism:Rеtrospесt and mе). Wе thus offеr a fеw rеmarks r and soсial organizations will rеэlutionarybiology and will havе a nfliсt.Еvolutiorrarymеdiсinе is alnd аnd trеat сеrtain disеasеs (seе )isеasеand Darwinian Mеdiсinе'' volutionary psyсhology offеrs in. and our potеntial to modify and )rmations in our lеgal systеms and ior аnd SoсioЬiology'' Ьy Daniеl I. [ есononriсthеory with еvolutionr еvolutionary thеory nеw сonсеphеory and thе notion of stratеgiеs. llaсing traditional idеas of an ..in.ual aсtors shapеd Ьy thеir еvoluions of еvolutionаry thеory еvеn сomputеrsсiеnсеas thе prinсiples ithmshavе opеnеd nеw vеnuеs for сh as thе dеsign of airplanе wings ;oсiеtyalso providеs an impoгtant : and soсiеty morе gеnеrally. Thе е Ьеst-studiеdarеas in thе history s in whiсh sсiеntifiс rеsцlts еmеrgе invеstigationsand what сan Ье 'lthough thеsе studiеs hаvе lеd to ls havесontriЬutеdto popular unphilosophеrs of sсiеnсе to rеthink naturе of sсiеntifiс еvidеnсе and lnd thеorеtiсal praсtiсеs сan lеad of naturаl phеnomеna. Somе еvеn ;s of finding thе ..truth'' in sсiеnсе :lе. going interaсtions Ьеtwееn еvoluиolutionarythеory transforms our soсial/сulturalЬеings. As propois no inhеrеnt diffеrеnсе Ьеtwееn soсiеtiesand сulturеs еvolvеd. Innary thеory to suсh arеas as thе ;mission.hasallowеd thеsе propoty and сulturе that is matеrialistiс

without Ьеing r"rrrdulУ gеnе сеntеrеd and rеduсtionistiс.Thе insight that soсiаl organization and сultuгal tгanstnissionaге govегnеd Ьy the samе gеnеral prinсiplеsof thе rеpliсator еquirtion impliеs (1) that not еvеrythingthat is thе produсt of еvolution has to Ье gеrrеtiсallydеtеrminеd and (2) that many phеnomеna (suсh as thе еvolution of сoopеration) that rеmain puzzling whеn studiеdwithin iust onе lе/еl of analysis (gеnеtiсor soсial/сultural)сan Ье rеsolvеd whеn thеy arе approaсhеd from Ьoth dirесtions. \Х/ithoutdouЬt this сurrеntеxtеnsion of еvolutionary theory to soсiеty will Ье an important and сontrovеrsiаlсontinuation of thе long history of еvolution аnd soсiеty. .!Йе of сoursе, all this сan Ье takеn too faг. must kееp in mind that еvolutionary thеorу might providе an ехplanation for soсiеty' Ьut it саnnot prоvidе a justifiсation. Еvolution also сannot providе an еpistеmiс justifiсation for еthiсal thеory, for ехamplе, dеspitе thе numеrous attеmptsto do so. ..Is'' сannot lеad to ..otrght.''Еvоlution сannot tеll us how soсiеtiеs ought to Ьеhavе,ехсеpt insofar аs it follows that soсiеtiеsmцst aссеpt еvoltrtionarythеory as good sсiеnсеif thеy аgrее to aссеpt sсiеnсеirt all.

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1996. Мoпаd to Мап: Thе Сoпсеpt сlf Progrеss iп Еuсllиtioпаrу Biolrtgу. Сambridgе, МA: Нarvard Univеrsity Prеss. 2ООЗ. Dапaiп апd Design: Does Еuolutiсlп Наuе а Purposе! СamЬridgе, МA: Hаrvаrd Univеrsity Prеss. Sеmon, R. 1908. Diе Мпeme аls erhаlteпdеs Priпzip im Wесhsеl des сlrgапisсhеп G еsсh еhепs. I-еipzig: Еngе]mann. Smoсovitis, У. B' t996. Uпifуing Biolсlgу: Тhе Еuolutioпаrу Sупthеsis апd Еuсllutiсlпаrу Biсlklgу. Prinсеton, NJ: Prinсеton Univеrsity Prеss. SoЬеr,Е.' and D. S. Wilson. 1998. Unto Оthеrs: Tbе Еuolutioп апd Psусhologу of Uпsеlfish Bеhаuirlr. Сambridgе, \4A: Hаrvard Univегsity Prеss. Todеs, D. P. 1989. Dаrшiпluithoиt Маlthus:Thе Strugglеfor Ехistепсе iп Russiап Еuolutionаrу Thoиght. Nеw York: Oхford Univеrsity Prеss. '!(аssеrsug' R. J., and M. R. Rosе. 1984. A rеadеr,sguidе and fеtrospесtivеto thе 1982 Darwin сеntеnnial. Quаrtеrlу Reuiеt'uof Biologу 59, nо. 4: 417-4З7. Wеismann, А'. 1892. Dаs Keimplаsmа: Еiпе Тheoriе dеr Verеrbuпg. Jеna: Fisсhеr. Wilson, L. o.1975. Soсiobiologу: The Nеtu Sупthеsis,СamЬridgе, MA: Bеlknap Prеss of Нarvard Univеrsity Prеss. Zieg|er, H. Е. 1918. Die Verеrbuпgslеhrе iп der tsiologiе uпd iп dеr Soziologiе. Jena: G. Fisсhеr.

З47

Еvolution and Rеligion Dаuid N. Liuingstonе

..Soаpy Sаm'' \trilЬеrforсе,thе Ьishop Еvеr sinсе thе mythiс еnсountеr Ьеtwееn ..Darwin,s Ьulldog,'' at thе 1860 mееt. of oхford, and Thomas Hеnry Huхlеy, ing of thе Bгitish Assoсiation for thе Advanсеmеnt of Sсiеnсе' thеrе has Ьееna widеspгеad sеnsеof an ongoirrg and inеvitaЬlе сlash Ьеtwееn еvolution and rеligion. Thе lristoriсal narrаtivе of tlris еnсOulltеr' howеvеr, provеs to Ье гаthег lеss сlеar-сut that suсh irnprеssionism miglrt suggеSt.In thе pagеs that follorv wе еxaminе thе rеligious viеws of Darwin himsеlf and somеthing of thе historiography of thе dеЬate Ьеforе introduсing Сatholiс, Protеstаnt' Jеwish, and Islamiс rеsponsеsto his thеory. A numЬеr of rесurring thеmеs еп1еrgеfrom this historiсal survеy' and a rеviеw of thеsеissuеsсorrсltldеsthis еss:ly.

Darwin's Rеligious Еvolution Syms Covirrgton Was }lМS Bеаglе's fiddlег, ship's Ьoy, and odd'joЬ man. For just ovеr siх yеars hе was also Сharlеs Darwin's sеrvаnt.Bесаusеhе was thе evеr-prеsеllt aссеssory to Darwin's gеogrаphiс arrd sсiеntifiс travеls, it is hardly surprising that this virtually invisiЬlе Darwinian adjunсt would soonеr or latеr сatсh a novеlist's imaginаtion. Thе final fеw sеntеnсеsof Rogеr МасDonald's fiсtionirl aссount of Сfthе геlа..Hе saw Darwirr on his knееs,aпd tionship Ьеtwееnеvolution and rеligion: thеrе was no diffеrеnсеЬеtwееn prayеr and pulling a Worп from thе grass. As for Мr Сovington, hе prayеd in thе old-fashionеd way.'' Thе еlision Ьеtwееn thе transсеndеntalаrrd thе aеsthеtiс tlrat is сapturеd hеrе rеsonatеs with Miсhaеl Rusе's сonсlusion to his rесеnt ilссount in Dаrtuitl апd Dеsigп. Fully irwirгеof Darwin's rеpеatеd rеsort tO thе languagе of Ьеаuty and worrdег ..of thе gеnuinе in thе nаtural ordеr, Rusе (2003, 335) rеn-lindshis rеaders ..ovеrwhеlming joy''-an lovе and еxpеriеnсе'' touсhing on thе spiritualthat еvolutionists sеnsеin thеir еnсountеrsr'viththе organiс rvorld. Hеrе wе ..Hosannah'' in intoхiсаrtеddеlisht arе alеrtеd tсl thе Dаrwin who brеathеd at thе suЬlinrity of thе primеval Bгаziliаn rаin frlrеst. З48

Givеn the сompliс mеntion Tlromas Hе ..dееp sеnsе of rеligi (quotеd in Brownе 2 naturе of Darwin's o at what point? Did Ь to do with it? Did аntiеvolutiorristsali k Тhе idеa that Dаrv сontеstеd Ьy thosе l to thе еnd'' (Moorе

spiritual momеnts lr; Ьooks dating frorl tl William Palеy's ассo sign; and thе pеrson trinе'' of еtеrnal rеtri dеath of his dеlightf thosе who insist tlrtrt mind, and еmotion (

athеism or mеtapЬy Ьimsе\i tutnеd arчar сrusading sесulаrist Sinсе irrеsоlrttiо iudgmеnt of thеsер ing to diagnosе D: hеsitanсy arе morе wavеring to whiсh fЪr еxamplе, hе r,vr this is alwavs pair" athеistiсally. But I r wish to do, еvidеn othеr hаnd I сanno еspесially thе natur brutе forсе'' (Burkh of vaсillation sttrfа ..truсklе'' to puЬliс thе origiп oi S1lесi ] 00 timеs. Aссor'rn Josеph Dalton Hoо] 1879 note tсl J' For< tuatеs'' (quotесl in (|986, 27) сonсlus to еЬЬ and flow.. mаtiс athеist; at hig Ьasiсally agnostiсmit hirnsеlf oп suсh

Еuolutkln апd Religioп

еligion

Soapy Sam'' WilЬеrforсе' thе Ьishop )arrvin'sЬulldtlg,'' at thе 1860 mееtnсеmеntof Sсiеnсе,thеrе has Ьееn a aЬlе сlash Ьеtwееnеvolution and rе)untеr' howеvеr, provеs to Ье rathеr ;ht suggеst.In thе pagеs that follow himsеlf and somеthing of thе historg Catholiс, Protеstant, Jеwish, and cf rесurringthеmеsеmеrgе from this u е sс o n с | u d с tsh i s е s s a y .

:r,ship'sЬoy, and odd-joЬ man. For arwin's sеrvant.Bесausе hе was thе 3raphiс and sсiеntifiс travеls, it is rvisiЬlе Darwinian adiunсt would nation. Thе final fеw sеntеnсеs of Covington in Мr. Dаrшiп's Shoсlter hе hеart of any aссount of thе rela..Не saw Darwin on his knееs, and rnd pulling a Worm from thе gгass. эld-fashionеdway.'' Thе еlision Ьеrtiс that is сapturеd hеrе rеsonatеs ]еntaссount in Dаrшiп апd Dеsigп. l thе languagеof Ьеauty and wondеr 'еmindshis rеaders ..of thе gеnuinе гiеnсе''touсhing on thе spiritualrs with thе organiс world. F{еrе wе ..Hosannah''in intoхiсatеd dеlight rain forеst.

Givеn thе сompliсаtions that сlЬsегvationsof this сlass introduсе, not to mеntionThomas Hеnry Huхlеy's rеmark to Сharlеs Kingslеy in 1860 that a ..dееp sеnsе of rеligion is сompatiЬlе with thе еntirе aЬsеnсе of thеology'' (quotеdin Brownе 2002, З10), it is not surprising that opinions diffеr on thе naturеof Darwin's owi rеligious сonviсtions. Did hе losе faith еntirеly? If so' at what point? Did his thеory of еvolution Ьy natural sеlесtionhavе anything to do with it? Did hе undеrgo a dеathЬеd сonvеrsion? Еvolutionists and antiеvolutionistsalikе havе a stakе in thе fаtе of Darwin,s soul. Thе idеa that Dаrwin movеd inеxoгaЬly from Ьеliеf to agnostiсismhаs Ьееn сontеstеd by thosе who arе сonvinсеd that hе rеmainеd а ..muddlеd thеist to thе еnd'' (Мoorе 1985' 438). Similarly, a vаriеty of supposеdly diagnostiс spiritual momеnts havе Ьееn idеntifiеd: thе matеrialism disсеrniЬlе in notеЬooks dating from thе latе 18З0s; his growing douЬts aЬout thе adеquасy of !Иilliam Palеy's aссount of сrеation with its roЬust сonfidеnсе in divinе dеsign; and thе pеrsonal moral dilеmmas hе suffеrеd ovеr thе ..damnaЬlе doсtrinе'' of еtеrnal rеtriЬution with thе loss of his father and thе sеnsеlеss,сruеl .ГЬеre dеath of his dеlightful daughtеr Anniе (Мoorе 1989, 797). arе' too' thosеwho insist that an intеrеst in сultivating a naturаlistiс aссount of spесiеs, mind, and еmotion сannot Ье сonstruеd аs еvidеnсе of еithеr thoroughgoing athеismor mеtaphysiсal mаtеrialism (Gillеspie |979) еvеn though Darwin himsеlf turnеd away from Сhristianity. Rеgardlеss, thе imagе of Darwin as сrusadingsесularistfails to do justiсеto thе сomplехitiеs of thе сasе. Sinсе irrеsolution on Darwin's spiritual statе sееms to bе thе сollесtivе 1udgmеntof thеsеportrayals, thе languagеof сеrtainty аnd prесision in sееk. ing to diagnosе Darwin's spiritual сondition is misplaсеd. AmЬiguity and hеsitanсyarе morе appropriatе' all thе morе so sinсе thеy сonvеy thе sеnsеof wavеringto whiсh Darwin himsеlf gavе voiсе. In an 1860 lеttеr to Asa Gray, for ехamplе,hе wrotе: ..\Иithrеspесtto thе thеologiсal viеw of thе quеstion; this is always painful to mе.-I am Ьеwildеrеd.-I had no intеntion to writе athеistiсally.But I own that I сannot sее' as plainly аs othегs do, & as I shd. wish to do, еvidеnсе of dеsign & Ьеnеfiсеnсеon all sidеs of us . . . on thе othеrhand I сannot anyhow Ье сontеntеdto viеW this wondеrful univеrsе & еspесiallythе naturе of man, & to сonсludе that еvеrything is thе rеsult of brutеforсе'' (Burkhardt and Smith 1985_2005, 8:224)' Thеn agаin his sеnsе of vaсillation surfaсеdin his shifting judgmеntsaЬout whеthеr hе was wisе to ..truсklе'' puЬliс to opiniсln аnd rеfеr to thе Pеntatеuсhal term сrесltion io Оп the Оrigiп of Speciеs(1859), thoшghhе aсtually usеd it аnd its сognatеsovеr 100 timеs. Aссount too must Ье takеn of his сommеnts in an 1870 lеttеr to ..my thеology is a simplе muddlе'' and thеn in an JosеphDalton Hоokеr that 1879 пote to J. Fordyсе that on thеologiсal mattеrs ..my judgmеnt oftеn fluсtuatеs'' (quotеd in Brсlwn 1986,25, З1). Suсh rеmarks сonfirm Brown's (1986,27) сonсlusion that Darwin's rеligious Ьеliеfs ..nеvеrеntirеly сеasеd to еЬЬ and flow . . . At low tidе, so to spеak, hе was еssеntially аn undogmatiсathеist;at high tidе hе Was а tеntativеthеist;thе rеst of thе timе hе was basiсallyagnostiс-in Sympathywith thеism Ьut unaЬlе oг unwilling to сommit himsеlf tln suсh impondеraЬlеqttеstions.''

.t49

З.'0

Еuolutioп апd Religion Thе impaсt of rеligion on Darwin, howеvеr, сannot Ье rеstriсtеdto fluсtuations in his spiritual tеrnpеraturе.Thе influеnсе of Palеy's Nаturаl Thеolrlgl' (1802), for ехamplе' lirrgеrеdlong. Thе сonnесrions Palеy Ьеliеvеd hе сoLrld disсеrn Ьеtwееn divirrе сrеаtivity аnd human agеllс),providеd Daгwin with an aЬsorЬing ar-ralogy:natural sеlесtion' Nature, Dаrwin judgеd, was involvеd in thе sеlесtion of organiс forms rathеr likе thе mannеr in whiсh pigеon fanсiеrs piсkеd out thе most promising variations. As hе lrimsеlf famously put it: ..Natural sеlесtionis daily and hourly sсrutinizing' throughout the world, еvеry variation' еvеn thе slightеst;rеjесtingthat whiсh is Ьad, prеsеrving and adding up all that is goоd'' (Darwin' |959, 168-169).In somе wаys Darwin's Naturе took on thе attriЬutеsof Palеy's God. Tо this wе пright add thaс suсh сonсеpts as organiс adaptation and thе harmony of nаturе wеrе as сепtral to Palеy's сosmogony as thеy Wеrе to Darwiп's. Yеt Dаrwin's сognitivе indеbtеdnеssto thеology сi1lltlotЬе limitеd to arсhitесtural есhoеs of Palеy. Sorте of his most profound сonviсtions еmеrgеdin dialoguе with-or in dеfianсе of-соnvеntional Сhristian doсtrinе. His сritiquе of natural thеology, it has Ьееn suggеstеd,was umЬiliсally сonnесtеd to his growing сonviсtions about thе links Ьеtwееnhunran and animal-how сoLrld thе produсts of an adv:rnсеd monkеy-mind Ье trustеd? His allеrgy to thе miraсulous was inflamеd Ьy a rеading of Palеy's ЕL,ideпсesof Сhristiаltitу ( \ 7 9 4 ) ; h i s s е n s i t i v i t , tvo s r . r f f e r i n ga,s D о n a l d F l е m i r r g( 1 9 6 1 . 2 3 1 ) s p е с u latеd, may havе owеd its intеnsity to a ..yеaгningaftеr a Ьеttеr God than God''; and his douЬts aЬout tеlеology wеге nurturеd Ьy an inaЬility to rесonсilе thе doсtrinе of divinе providеnсе witlr lifе's daily dеtails (Brookе 1985). Takеn ovеrall' sсiеnсеand rеligion wеrе, in onе Wаy or anothеr' thor. oughly intеrtwinеd in Darwin's lifе and thought.

Сlеaring thе Grоund On thе faсе of it, Daгwin's thеory posеd сlrallеngеsof еpiс propoгtioпs to Сhristian Ьеliеf at еvеry turn. It mythologizеd tlrе Мosaiс narrаtivе of spесial сrеation; it smashеd through thе praсtiсе of using ЬiЬliсal gеnеalogiеsto datе еarth history; it rеmoved thе idеa of divinе dеsign from naturе Ьy dеmonstrating how spесiеsсamе aЬout through thе оrdinary, humdrum proсеssеs of natцral sеlесtion; it rеvеalеd that humans wеrе! in somе fundamеntal sеnsе)no diffегеntfroп-raninrzrls;it rootеd morаl sеnsibilitynot in thе hun-ran suЬjесt dignifiеd as God's imagе Ьеагеr Ьut in thе pгimitivе irnpulsе of a strugglе foг survival; it wаs nехt-door nеiglrЬor to thе Frеnсh m:rtеrialism thаt had Ьееn infiltr:rtinginto Britain through Lamarсkian-еnthusеdmеdiсal radiсals who moЬilizеd it to attaсk thе Angliсan-Tory еstaЬlishmеnt.Not surprisingly, thе idea of a protraсtеd Ьattlе Ьеtrvееn sсiеnсе and rеligion rесеivеd its grеatеst impеtus from ninеtееnth-сеntLlrytrеatisеs that сhartеd, as in thе сasе of сhеmist-tLrrnеd-historian John Dгаpеr, tЬe Historу of tbе Сoп(1875 bеttuееп Rеligioп Sсiепce апd fliсt ) or, in thе rvords of Andrеw \ffhitе,

prеsidеnt of Сornеll Theologу iп Сbristеr muсh to сonfirm thе i forсеs of еnlightеnеd l But thе сrisp сlarit Straсtion for historiсс еrеd. For a start' at iеi of thе Gеnеsis rесord stratеgiеs to maintain еlaЬoratеd, and thе id minds of еarly Viсtol took a variеty of foг сhallеngе, and of сou Angliсanism and striс thе dеsign argumеnt \ and William 'Whеwе сrеation Ьy natural l opеnеd thе door to tl ways in whiсh еvolut takеn, аnd сontinuе tr What furthеr сomp ists and rеligious Ьеl thе sidе of sесular zе Thomаs Hеnry Huxlе сlub, who dеdiсatеdt] alikе. No soonеr did of еvolution than hе f ology to insist that е nism to that vigoro moral' and soсial lifе 1991' 308).Thеn, in through gеologiсal sg rapе, murdеr & arsс (quotеd in Dеsmond ..sсiеntifiс аЬout thе 1 to сrеation''' dеnomi ..t daining friеnds to tеlеologу''' At thе samе timе aс сial agеndas in dеlivi сasе of Drapеr, who mation' thе rеal objе doсtrinе of papal infa prophеsy that it woul friеndly govеrnmеnts

Еuolutiсlп апd Religioп .еvеr'сannot Ье rеstriсtеd to flцсtufluеnсеof Paley's Nаtиrаl Thеologу :onnесtionsPalеy Ьеliеvеd hе сould man agеnсyprovidеd Dаrwin with . Naturе, Darwin judgеd, was inгathеr likе thе mannеr in whiсh piэmising variations. As hе himsеlf [y and hourlv sсrutinizing' thrоugh. lightеst;rеjесtingthаt whiсh is Ьad, ,od" (Darwin, 1959, 168-169). In lttriЬutеsof PalеyЪ God. To this wе adaptationand thе harmony of na.as thеy wеrе to Darwin's. Yеt Darсаnnot Ье limitеd to arсhitесtural nd сonviсtionsеmеrgеd in dialoguе Сhristian doсtrinе. His сritiquе of , was umЬiliсally сonnесtеd to his ееnhuman and animаl-how сould rind Ье trustеd? His allеrgy to thе >fPalеy's Еuidепсes of Сhristiапitу lonaldFlеming (1961, 231) spесu..yеarning aftеr a Ьеttеr God than еrе nurturеd Ьy an inaЬility to rес:е with lifе's daily dеtails (Brookе l Wеrе'ln onе Way or anothеr' thorhought.

c сhallеngеsof еpiс proportions to 1izеdthе Мosaiс narrativе of spесial of using ЬiЬliсal gеnеalogiеsto datе zinе dеsign from naturе Ьy dеmonl thе ordinary, humdrum proсеssеs lmаns Wеrе' in somе fundamеntal l moral sеnsiЬilitynot in thе human Ьut in thе primitivе iпrpulsе of a rеighЬor to thе Frеnсh matеrialism ough Lamarсkian-еnthusеd mеdiсal Angliсan-Tory еstaЬlishmеnt. Not 'tlе Ьеtwееn sсiеnсе and rеligion rеth-сеntuгytrеatisеsthat сhartеd' as lhn Drapеr, tЬe Historу of tbе Сon.!Иhitе' ) or' in thе words of Andrеw

prеsidеntof Сornеll Univеrsity, A Historу of thе Wаrfаrе of Sсieпсe luith Тhеologу iп Сhristeпdom (\896). Thе vеry titlеs of works likе thеsе did muсh to сonfirm thе imprеssion of a monumеntal dеath strugglе Ьеtwееn thе forсеsof еnlightеnеd sсiеnсе and Ьеnightеd rеligion. But thе сrisp сlarity оf this rесеivеd imagе suЬstitutеs monoсhromе abstraсtion for historiсal tесhniсolor. Thеrе is a riсhеr narrativе to Ье unсov,,days', еrеd.For a start' at lеаst sinсе Аugustine, many Ьad read thе сrеation of thе Gеnеsis rесord symЬoliсally rathеr than litеrally. Various harmonizing stratеgiеsto maintain сonсord Ьеtwееn Gеnеsis and gеology had long Ьееn еlaЬoratеd,and thе idеa of a lеngthy еarth history was wеll еstaЬlishеd in thе minds of еarly Viсtorian Сhristian gеntlеmеn.gеologists. Natural thеology took a variеty оf forms' somе lеss susсеptiЬlе to Darwin's antitеlеologiсal сhallеngе' and of сoursе thеrе wеrе traditions, likе сеrtain strands of high Angliсanism and striсt unsеntimеntal Сalvinism, for whiсh thе signifiсanсе of thе dеsign argumеnt was nеgligiЬlе. And thеrе wеrе thosе likе John Hеrsсhеl and William !Иhеwеll whosе rеligious outlook prеdisposеd thеm to strеss сrеation Ьy natural law rathеr than Ьy divinе intеrvеntion' a movе that opеnеdthе door to thе idеa of еvolution as God's mеthod of сrеation. Thе ways in whiсh еvolution and religion сould Ье madе to fit onе anothеr havе takеn,and сontinuе to takе, myriad forms. lfhat furthеr сompliсatеs mattеrs is that whеn сonfliсt Ьеtwееn еvolutionists arld rеligious Ьеliеvеrs did oссur, thе сampaign was oftеn wаgеd from thе sidе of sесular zеalots as muсh as from thеologiсal rеaсtionariеs. Takе Thomas Неnry Нuхlеy, a kеy mеmЬеr of that Darwinian gingеr group, thе Х сluЬ,who dеdiсatеd thеmsеlvеs to driving out of powеr Palеyitеs and parsons alikе' No soonеr did hе hеar of thе Сatholiс St. Gеorgе Mivart's advoсaсy of еvolution than hе fеrrеtеd out a сopy of Franсisсo Suarеz's Sсholastiс thе..сomplеtе ology to insist that еvolution was in and irrесonсilaЬlе antagonism to that vigorous and сonsistеnt еnеmy of thе highеst intеllесtual, moral,and soсial lifе of mankind-thе Сatholiс Сhurсh'' (quotеd in Brookе 1991, 308). Thеn, in irritation at thе stratеgiеsof thosе whо rеad Gеnеsis ..provе that throughgеologiсal spесtaсlеs,hе dесlarеd his dеtеrmination to ..positivеly rapе,murdеr 6( arson'' wеrе еnjoinеd'' in thе old Tеstаmеnt (quotеdin Dеsmond and Moorе 1991, 472). Bеsidеs,hе was forеvеr talking ..hymns aЬoutthе ..sсiеntifiсpriеsthood,'' prеaсhing ..lay sеrmons,'' singing to сrеation''' dеnominating himsеlf a ..Bishop'' of thе nеw ессlеsiology, or..molесular ..thе dainingfriеnds to сhurсh sсiеntifiс,'' and ехpounding his tеlеologу.'' At thе samе timе advoсatеs of сonfliсt historiеs havе also had thеir own soсial agеndasin dеlivеring pugilistiс ассounts of sсiеnсе and rеligion. In thе сasеof Drapеr' who rеmarkеd that sсiеnсе was thе twin sistеr of thе Rеformation' thе real oЬjесt of opproЬrium Was thе Romаn Сatholiс Сhurсh; thе doсtrinеof papal infalliЬility еnunсiated in 1 8 70 appallеd him and lеd him to prоphеsythat it would Ьring thе Сatholiс Сhurсh into сonfliсt with hithеrto.W.hitе, friеndly govеrnmеnts. As for thе opposition that his nonsесtarian

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Еuolutioп апd Rеligiсlп Сornеll Univеrsity had attraсtеd from сlеrgymеn strеngthеnеd his геsolvеto kееp sсiеnсе at thе forefront of thе сurriсulum; Сornеll would Ье an asylum foг sсiеnсе liЬеratеd from thе striсturеs of rеligiоus dogma. It was manеuvеrs of this kind that promptеd somе historians to rесonсеptualizеthе so-сallеd warfarе Ьеtwееn sсiеnсе and rеligiоn in Viсtorian soсiеty as a soсial strugglе Ьеtwееn two сontеnding intеllесtual еlitеs-namеly, thе old-fashionеd parson and thе nеwly professionalizеdsсiеntist (Turnеr 1978|.In this sсеnario dеbatеs aЬout sсiеntifiс knowiеdgе in gеnеral and еvolution in partiсular sim. ply Ьесamе a furthеr arеna in whiсh tusslеs for сultural suprеmaсy wеre played out. Howеvеr alluring grand narrativеs may Ье, storiеs of thе еnсountеr Ьеtwееn еvolution and rеligion that tradе in systеmiс сonfliсt or, for that mattеr' сoopеration sасrifiсе historiсal intriсaсy tо linеar simpliсity. In faсt, rеligious Ьеliеversrеspоndеd in vastly diffеrеnt Ways to еvоlution, and thеir stanсеs do not follow any straightforward taxonomy of thеologiсal oriеnta. tion' dеnominational affiliation, or doсtrinаl prеoссupation. Bеsidеs,еvolu. tionary thеory Was nеvеr еnсountеrеd in a сultural vaсuum' and dеЬatеs aЬout it routinеly Ьесamе a mеans of giving voiсе to a rangе of othеr anхiеtiеs. Somеthing of thе divеrsity of thеsе еngagеmеnts mаy Ье glеanеd from thе following thumЬnail skеtсh.

Thе Viеw from Romе Сatholiс opinion on еvolution has long Ьееn dividеd. From thе еarly days thе opposition of a group of Jеsuit thinkегs Ьrought togеthеr Ьy Popе Pius IХ to сomЬat thе forсеs of modеrnity Was ехprеssеd through thе pagеs of La Сiuiltd Саttolicа' an outlеt that ехеrtеd vеry сonsidеraЬlе influеnсе among ItalianJеsuits. Thus in thе еarly 1860s thе nесеssityof maintaining thе fiхity of spесiеsagainst Lamarсkian idеas of transformism was vigorously promulgatеd by G. B. Piаnсiani in its pagеs (Brundеll2001). By сontrast' thе еfforts of thе Еnglish сomparativе anatomist St. Gеorge Jaсkson Мivart' a Сatholiс сonvеrt' to Сhгistiаnizе еvolution through a Lamarсkian rеading of transmu. tation in his 1871 volumе Оп the Geпеsis of Species was praisеd in thе Catholiс prеss. Huxlеy might snipе that Mivart сould not Ье a sturdy sоldiеr of sсiеnсеand a loyal son of Romе, Ьut Popе Pius IХ аwardеd him thе dеgrее of doсtor of philosophу ln 1876, and the Bеlgian Ьishops prеssеdhim to takе up a сhair аt thе Univеrsity of Louvain in 1884, although hе latеr fеll into disfavor on aссount of сеrtain thеologiсal writings. Howеvеr voсifеrous thе opponеnts of еvolution undoubtеdly wеrе, thе offiсial сustodians of Catholiс dogma did not takе any aсtion against Catholiс еvolutionists until thе 1890s whеn attitudеs Ьеgan to hardеn as thе aging Popе Lеo ХIII, hithеrto a forсе for modеration, lost ground to thе inсreasing influеnсе of Roman Jеsuits and thе maсhinations of thе СiuiltЙ Саttoliса сotеriе. So whilе Мivart's еfforts еsсapеd at lеast for a timе thе сеnsurе of thе Vatiсan' othеr Сatholiс еvolutionists did not farе so favoraЬly' notaЬly thе

Frеnсh Dominiсan priе o r g а п i q И е s( 1 8 8 7 ) ,a n d rolе in thе dеvеlopmеnt |ished Еuolution аnd Dt Both thеsе writеrs su1 Ьеit within сеrtаinlimi foundations, was dirесt thеologiсal еnеmiеs of t] might Ье thе produсt Saсrеd Сongrеgation ol . . е v o l u t i o nt h е o r yi tЬаt human Ьody'' (quotеd Ьook was сеnsцrеdwas spееdily rеtraсtеd in tht find ways of rеvisiting t of thе Ьook, Ьut it too : It was muсh thе sam rесognition for his Sс Саtb oliс Sсieпtists (789

sсепt of Мш1 as thе сaU аnd Dogmа was to dеп ..to admirе' muсh in it xx). Likеwisе groundе tiс ехеgеsisto justify a intеrnational suссеss,a of a fuming Сiuiltй Саt lеnt with rесklеss assс sumptions. Thе Сongr vеry largеly on thе ma lutionism was part of z tion of tехtuаl сritiсi ессlеsiastiсal affairs. L voraЬlе rеviеw hе rесе pains, prеSеntlyсamе l Various faсtors play i51ц''-1hg tеndеnсy or indеpеndеnсе and to : suсh forсе. This indrс сеntury Сatholiсs wеr with whiсh immigran сеrns rotatеd аround t arly trеnds, notably t Ьiology wеrе thus ofl to еstablishеd ways o authority and who hа Thosе who found еvс

Еt,ollttioп апd Rеligioп gymеn strеngthеnеd his геsolvе to lum; Сornеll would Ье an asylum .еligiousdogma. It was manеuvеrs Lsto rесonсеptualizеthе so-сallеd сtoriаn soсiеtyas a soсial strugglе _namеly, thе old-fashionеd parst (Тurnеr 1978). In this sсеnario al аnd еvolution in pzrrtiсularsimslеs for сultural suprепraсy wеrе ' Ье, storiеs of thе еnсountеr Ьеs,vstеmiссonfliсt or, for that matilсy to linеar simpliсity. In faсt, ]геntWаys to еvolution' and thеir taхonomy of thеologiсаl oriеntatаl prеoссupation.Bеsidеs' еvolua сultural vaсuum' and dеЬatеs rg voiсе to a rangе of othеr anxingagеmеntsmay Ье glеarrеd from

n dividеd.From thе еarly days thе lught togеthеr Ьy Popе Pius IХ to 'rеssеd through thе pagеs of Lа :ry сonsidеraЬlеinfluеnсе among nесеssityof maintaining thе fiхity sformismwas vigorously promultеll 2001). By сontrast' thе еfforts еorgеJaсkson Mivart, a Сatholiс r Lamarсkian rеading of transmu_ is of Spесiеs was praisеd in thе vaгt сould not Ье a stuгdy soldiеr е Pius IХ awardеd him thе dеgrее :lgiarrЬishopsprеssеd him to takе 1884, although 1rеlаtсr fеll into rritings. llution undouЬtеdly wеrе' thе oftakе any aсtion against Сatholiс еs Ьegan to hardеn as thе аging i o n . I o s tg r o u n d t o t h е i n с г е а s i n g rtiorrsof tЬe Сiuiltа Саttolicct сoеastfor a timе thе сеnsuге of thе ot farе so favoraЬly, notaЬly thе

Frеnсh Dominiсan priеst M.-D. Lеroy, author of L'ёuolutioп des espёсеs orgапiques(1887), and thе Amеriсan Jоhn Zahm, who playеd ir signifiсant rolе in thе dеvеlopmеnt of thе Univеrsity сlf Notrе Damе in Indiana and pub|isЬedЕ,uolutioпапd Dogmа in 1896. Both thеsеwritеrs suppoгtеd thе thес;logiсalaссеptaЬility of еvolution' alЬеit within сеrtain limits' Lеroy's apologia, еrесtеd foursquarе on Mivart's foundations,was dirесtеd against both аthеistiс rеnditiorrsof еvolution and thеologiсalеnеmiеsof thе thеory. But Ьесausеhе hintеd that thе human Ьody might Ье thе produсt of еvolutionary forсеs, thе сardinal prеfесt of thе SaсrеdCongrеgation of thе Indеx of ProhiЬitеd Books issuеd thе judgmеnt ..еvolution thеory that is tеmеrarious and anti-Сhristian whеn аppliеd to thе human Ьody'' (quotеd in Brundеll 2001' 88). Although thе finding that his Ьook was сеnsurеdWas сonvеyеd to him privatеly' Lеroy was dеvastаtеdand spееdilyrеtraсtеdin thе pagеs of Le Мondс in Мarсh 1895. Latеr hе triеd to find ways of rеvisitingthе wholе issuе Ьy prоduсing a nеw' сorrесtеd vеrsion of thе Ьook, Ьut it too fеll foul of thе аuthoritiеs. It was muсh thе samе with Zahm, who had alrеady aсhiеvеd widеsprеad rесognition for his Sottпd апd Миsiс (1892) and Саtholiс Sciеnсe апd Саtholiс Scieпtists(1893). Although hе had еarliеr сondеmnеd Darwin's Desсеntof Мап as thе сausе of soсial inеquity, his purposе in writing Еuolutioп апd Dogmа was to dепlonstratеits thеologiсal aссеptaЬiliry.Indееd hе found ..to admirе' muсh muсh in it that is еnnoЬling and inspiring,' (Zahп-l,|896, xх). Likеwisе groundеd in Мivart's sуstеm' Zahm engagеd in dеtаilеd patristiс еxеgеsisto justify a tеlеologiсal rеndеring of еvolution. Thе Ьook was an intеrnationalsuссеss'and an Italian translation rapidly appеarеd,Ьut rеadеrs of a fuming СiuiltЙ Саttoliса wеrе assurеd that it was all a tissuе of liеs' rеdolеnt with rесklеss assеrtions' and hopеlеssly сompromisеd Ьy duЬious assumptions.Thе Сongrеgation of the Indех dеnounсed tt in 7897, foсusing vеry largеly on tЬе mаttеr of human origins. To traditionalists' Zalrm's еvolutionismwas part of a paсkаgе of radiсаl proposals tlrat inсludеd thе adoption of tеxtual сritiсism and thе ir-rсrеasingsеgrеgation of асаdеmiс and ессlеsiastiсalaffairs. Likе Lеroy, ZaЬm withdrеw his еfforts dеspitе thе favoraЬlе rеviеw hе rесеivеd from thе Еnglish Ьishop John Hеdlеy, who' for his pains, prеsеntly сamе undеr thе whiplasЬ of СiuiltЙ Саttoliса tonguеs. .,AmеriсanVarious faсtors playеd thеir parts in thеsе intriguеs. A fеar of ism''-thе tеndеnсy on thе part of Amеriсan Catholiсs to display intеllесtual indеpеndеnсеаnd to adapt Сatholiсism to arr Amеriсan сOntеYt-was onе suсh fоrсе. This indiсаtеs that Darwinian сontrovеrsiеsanlong turn-of-thесеnturyСatholiсs wеrе oftеn lеss aЬout sсiеnсеthan aЬout issuеs of idеntity with whiсh immigrant сommunitiеs wеrе grappling. Anothеr suitе of сonсеrnsrotatеd around thе routinе сonflation of Dаrwinism and modеrn sсholarly trеnds, notaЬly thе nеw ЬiЬliсal сгitiсism. Rеaсtions to еvolutionary Ьiology Wеrе thus oftеn all of a piесе with rеsponsеs to widеr сhallеngеs to еstablishеdways of thinking. Сritiсаl too Was thе mattеr of intеllесtual аuthorityand who hаd thе right to intегpгеtthе traditionЪ rесеivеd сanon. Thosе who found еvоlution in thе writings of Aquinas аnd Augustinе wеrе

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Еt,olиtioп апd Religioп arrogantly failing to pay duе dеfеrеnсе to thе history of nеosсholastiс сommеntary. Latеr, fеаrs of Darwinian-inspirеd еugеniс poliсiеs playеd their rolе in shaping Сatholiс еvaluations of еvolution (ApplеЬy 1999\' Dеspitе thеsе pеrsistеnt anхiеtiеs, Huxlеy's еfforts to prosсriЬе Мivart's Сatholiс Darwinism' and thе diffiсultiеs that Lеroy andZaЬm ехpеriеnсеd at thе hands of thе Сongrеgation of thе Indех, a suссеssionof Саtholiс sсholars havе сontinuеd to dеfеnd thе thеologiсal propriеty of Darwinian biology. During thе final dесаdеs of tlrе ninеtееnthсеntury, thе Сatholiс astronomеr Gеorgе Searlе dесlarеd that thе thеory of еvolutiorrеnjoyеd a strong faсtual Ьаsis and that human еvolution would not jеopardizе Сatholiс thеology. At thе samе timе thе Harvard anatomist Thomаs Dwight insistеd that thеrе was no сontradiсtion bеtwееn еvolutiorr and tеlеology. Thе thеologiаn John Gmеinеr addеd his sllpport in 1884 whеn, in Мoderп Sсiепtific Viец,s апd Сhristiап Doctriltеs Сompаred, hе wеnt so faг аs to сlaim that Augustinе had aсtually proпlotеd a vеrsion of еvolutionary thеory and suggеstеdthat Darwin сould arguaЬly Ье сonsidеrеd his disсiplе. Pеrhaps thе most сonsidеrеd Сatholiс statеmеnt оn thе suЬjесt in tlrе еarly dесadеs of thе twеntiеth сеntury appеarеd in Frеnсh tn 1927 (and in Еnglish transiation Ьy Еrnеst Меssеngег thе following yеaг) Ьy thе dirесtoг of thе Gеologiсal Institutе at thе Univеrsity of Louvain, Сanon Hеnri dе Dorlodot, who dеfеndеd not just thе lеgitimaсy Ьut thе intrinsiс doсtrinal plausiЬility of Darwinism. Not only Wеrе thеrе no sсriptural argumеnts against thе thеory' hе insistеd in Dаrtuiпism апd Саtholiс Thought, Ьut thе ..tеaсhingof thе Fаtlrеrsof thе Сhurсh is vеry fаvouraЬlе to thе thеory of AЬsolutе Еvolution'' (Dorlodot |922,4)' Сеntral to Dorlodot's diagnosiswas his dеvеlopmеntof thе сonсеpt of what hе сallеd Сhristian naturalism. Сonсеivеd as an antidotе to athеistiс and matеrialistiс еvolution' as wеll as to thе intеrvеntionist stanсе оf figurеs likе Gеorgеs Сuviеr and Alсidе d'oгЬigny, this сonсеpt еmphasized thе immanеnt workings of thе сrеator through nаtural proсеssеs.So еmphatiс was Dorlodot in this judglrrеntthat hе pronounсеd it lеgitimatе for Catholiсs to go еvеn furthеr than Darwin had donе whеn hе attriЬutеd thе initial origirr of living things to аn aсt of spесial divinе intеrvеntion. Сatholiс thеology, hе maintainеd, prеdisposеd its adhеrеnts to an advanсеd systеm of transformism and еven oЬligеd thеm to ассеpt thе idеa thаt all living bеings wеrе dеrivеd from a fеw еlеmеntary organisrns' All of this was rеpoгtеdlу in kееping with tlrе tеaсhing of thе сhurсh fathеrs. St. Grеgory of Nyssa's aссount of origins, for ..aЬsolutе ехamplе, was paradеd as a thеory of еvolution'' that lеft nO room ..еvеn for spесial intеrvеntion at thе origin of lifе'' (Dorlodot 1922,79)' Givеn Меssеngег'srolе as translаtor of Dorlodot's volumе' it is nor surprising that hе himsеlf turnеd in 1931 to a dеtailеdanalysis of thе thеologiсal propriеty of еvolution that Ьuilt on Dordolot's ..Ьrilliant piесе of woгk'' (Mеssеngеr 193 1, xxiv). Stagеd in thе introduсtory еssay Ьy Сharlеs Souvay ..noisy as poisеd Ьеtwееn thе аdvoсatеs of Protеstant Мodеrnism'' аnd thе ..stuЬЬornranks'' of ProtеstаntFundamеntalism,Mеssеngеr'svolumе undеrt
сlassiсаl writings of Еphrег а n d t h с l i k е o n t h е o r i g i nt sсourеd, as Was thе lvork с Rodrigo dе Arriaga. Thеsе Ь е r o f s p е с i f i сс o n с l u s i o n s ..Сhristiаtrrr turе аnd that thе сhurсh fаthеrs on thе р gег rеmindеd his rеаdегst} сondеmnеd еvolution as tl hе rеmained сonvinсеd tha Ьody-though not thе sor fully сorrrpatiЬlеwith Сath It would Ье mistakеn tr v o i с е s .Т а k е , f o г е x а n r 1 r l g i с i n е i n B i r m i n g h a m .p r е s i of anthropology in St. Ntiс and а сorrеspondеnt of Tlr tion аs ir Саtholiс аpolog Саtholiс Меп of Sciспсе (1 tailеd sсrutiny in his work .Writing at a timе WL 1917. сovеry of Mеndеl and thе а proposals' Windlе wаs aЬ Сatholiс vеrsion of пеo-La Dеspitе thеsе еfforts ant gеtiсs from thе Frеnсh Jеst thе miсl-twеntiеth сеntr-rr Сatholiсs sympathеtiс to tгасtеd :rdvеrsеrеeсtioll C a t h o l i с t h е o l o g i a n sa s J а larly' Tеilhard dе Сhardin proval and was prсlhiЬitеd lеss did lris work еliсit thе t е r M е d a w a r ( 1 9 6 7 ) ,t h е } fully dismissеd thе Phеlulп A m o r r g t h е o | o g i с aсl r i t i t . st s i s o f r h е h u m а n s p е с i е sа. сonсеrns' whеthеr ovеr pol to Саtholiсism than еithеr sеlесtion pеr sе bесar'rsеtlr tair-rеdat all thеologiсаlсo papal рronounсеmеnts hal of thе human soul Ьy dirес Сonsidеr Pius ХII's еn thinkеrs wеrе warnеd of th .,in tiеs' So whilе rеsеaгсh

Еuolиtiсln апd Rеligioп to thе history of nеosсholastiс pirеdеugеniсpoliсiеs playеd thеir [ution(ApplеЬу t999). еy's еfforts to prosсriЬе Mivart's rt Lеroy andZaЬm еxpеriеnсеd at , a suссеssionof Catholiс sсholars propriеty of Darwinian Ьiology. сеntury' thе Сatholiс astronomеr :volution еnjoyеd a strong faсtual . jеopardizеСatholiс thеology. At ras Dwight insistеd that thеrе was tеlеology. Thе thеologian John '. in Мodеrп Sсieпtifiс Viеttls апd so far as to сlaim that Augustinе 'ionary thеоry and suggеstеdthat isсiplе. ltеmеnton thе suЬjесt in thе еarly in Frеnсh in 1921(and in Еnglish rg yеar) Ьy thе dirесtor of thе Gеon, Сanon Hеnri dе Dorlodot, who гinsiсdoсtrinal plausiЬility of Darrgumеntsagainst thе thеory, hе in..tеaсhingof thе Fathеrs of Ьut thе of AЬsolutе Еvolution'' (Dorlodot las his dеvеlopmеnt of thе сonсеpt nсеivеd as an antidotе to athеistiс hе intеrvеntionist stanсе of figurеs гhisсonсеpt еmphasizеd thе immaal proсеssеs.So еmphatiс was Dor: lеgitimatеfor Сatholiсs to go еvеn triЬutеd thе initial origin of living tion. Сathоliс thеology, hе mainanсеd systеm of tгansformism and rll living Ьеings wеrе dеrivеd from ,as rеportеdly in kеeping with thе ' of Nyssa's aссount of origins, for olutе еvolution'' that lеft no room of lifе''(Dorlodot7922,79). D o r l o d o t ' sv o l u m е , i t i s n o t s u r dеtailеdanalysisof thе thеologiсal 'dolot's ..brilliant piесе of Work'' oduсtory еssаy Ьy Charlеs Sоuvay f Рrotеstant Modеrnism'' and thе talism,Mеssеngеr'svolumе undеrrough сhurсh history to vindiсatе (Меssеngеr1931, xviii, xix). Thе

сlаssiсalwritings of Еphrеm, Basil, Grеgory' Сhrysostom, Ambrosе, Aquinas, and thе likе on thе origin of living Ьеings,partiсularly thе human raсе' Wеrе sсourеd,as was thе work of lаtеr Sсholastiсslikе Suarеz,Aеnеаs Sylvius, and Rodrigo dе Arriagа. Thеsе еxсavatlonsWеrе marshalеd in support of а numЬеr of spесifiссonсlusions-that spontanеousgеnеrationWas taught in Sсripturе and that ..Сhristian naturalism'' undеrlay thе proсlamations of many of thе сhurсh fathеrs on thе passivе modе of divinе сгеation. Сеrtainly Меssеngеr rеmindеd his rеаdеrs that standard manuаls of Сatholiс dogma routinеly сondеmnеdеvolution as thеologiсally falsе and philosophiсally aЬsurd, Ьut hе rеmainеd сonvinсеd that thе еvolution of plants, animals, and thе human body-though not thе soul, whiсh rеquirеd a dirесt aсt of сrеatiсln-was fully сompatiЬlе with Сatholiс orthodoхy. It would Ье mistakеn to think that Dorlodot and Меssеngеr wеrе lonе voiсеs.Takе, for еxamplе, thе сasе of Sir Bеrtгam Windlе, FRS, dеan of mеdiсinе in Birmingham, prеsidеntof Quееn's Сollеgе Сork, and, latеr, prоfеssor of anthropology in St. Miсhaеl's Сollеgе' Toronto. A сonvеrt to Catholiсism and a сorrеspondеntof Thomas Hardy, Windlе sесurеd a signifiсant rеputation as a Catholiс apologist through his publiсation of works |lke Tшеlue Саtholiс Мeп of Sсiепсе (|912). Not surprisingly, еvolution сamе undеr dеtailеd sсrutiny in his work TЬе СЬцrсh апd Sсiепcе, whiсh first appеarеd in 1917. \Х/ritingat a timе whеn Darwinism was in есlipsе bесаusеof thе rеdisсovеryof Mеndеl and thе availaЬility of various non-Darwinian еvolutionary proposals,Windlе was aЬlе to ехploit to thе full his inсlinations toward a Сatholiс vеrsion of nеo-Lamarсkisпr. Dеspitе thеsе еfforts and thе sustainеd suссеssionof еvolutionary apologеtiсsfrom thе Frеnсh Jеsuit and palеontologistTеilhard dе Сhardin during thе mid-twеntiеth сеntury that sеrvеd as somеthing сlf a rallying point for Сatholiсs sympathеtiс to Darwin, Сatholiс support for еvolution has at. traсtеd advеrsе rеaсtions. Mеssеngеr rеportеd thе antagonism of suсh Сatholiс thеologians as Janssеns,Pignataro, Hugon, and Van Noort. Simi. larly, Tеilhard dе Chardin Was on thе rесеiving еnd of prе*Vatiсan II disapproval and was prohiЬitеd from spеaking puЬliсly on сеrtain suЬjесts.No lеss did his work еliсit thе Ьiting сеnsurе of a pгofoundly unsympathеtiс Pеtеr Mеdаwar \7967), thе NoЬеl Prizе*winning immunologist, who disdainfully dismissеd the Phепсlmепo|1of Мап as a work of philosophiсal fiсtion. Among thеologiсalсritiсs dеЬatе has routinеly сongrеgatеdaround thе gеnеsis of thе human spесiеs,a prеoссupation that сonfirms that anthropologiсal сonсеrns'whеthеr сrvеrpolygеnism or human anсеstry' Wеrе morе unnеrving to Сatholiсism than еithеr uniformitarian gеology or thе prinсiplе of natural sеlесtionpеr sе Ьесausеthе сonsanguirrityof thе human raсе had to Ье rеtainеd аt all thеologiсаl сosts (Astorе 1996). Thus various twеntiеth-сеntury papal pronounсеmеntshavе Ьееn сonсеrnеd to prеsеrvеthе spесial сrеation of thе human soul Ьy dirесt divinе intеrvеntion. Сonsidеr Pius ХII's еnсyсliсаl Humапi cепеris (1950). Hеrе Сatholiс thinkеrswеrе warnеd of thе dangеr of too еagеrlyеmЬraсing sсiеntifiсnovеl..intсl tiеs.So whilе rеsеarсh thе origin of thе human Ьody as сoming fгom

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Еuolиtion апd Religioп prе-ехistеntand living mattеr'' was allowеd' anv suggеstionthat thе humаn raсе Was оf plural origins was aЬsolutеly сondеп-rnеdЬесausеof its impliсations for thе doсtrinе of original sin. A similar stipulation pеrtainеd to thе origin оf thе lruman sor.rl,whiсlr Pius insistеdwas Ьеyond tlrе rеасh of еvоlr'r..Thе tionary transformisnr: Сatholiс faith oЬligеs us to hold that souls arе immеdiatеly сrеatеd Ьy God'' (Popе Pius ХII 1950' ч[36). Мorе rесеntly Johrr Pаul II addrеssеda plеnаry irssеmЬlyof thе Porrtifiсal Aсadеmy of Sсiеnсеsin OсtoЬеr 1,996r>nthе suЬjесt of еvolution and its sig. nifiсanсе for undеrstandingthе human agеnt. Rесalling Pius ХII's еnсyсliсal and noting that evolution had now gonе Ьеyond thе status of a mеrе hvpothеsis, hе сonсеdеd thе likеlihood that thе humаn Ьody had originatеd fronr prееxistеnt living mаttеr, Ьut hе still rеstatеd thе tгаditiсlnаl сrеationistas opposеd to trаduсiаnist-doсtrinе of rlrе оrigin of thе human soul irr ordеr ..thе ontologiсal lеap'' Ьеtwееn humanity and its to sustain what hе сallеd forеЬеars.By this movе mеtaphysiсalmаtrеrs rotilting around morality, сon. sсiеnсе,frееdom' aеsthеtiсаpprесiation, and spiritual ехpеriеnсеwеrе dеlеgаtеd to phiiosopЬiсal anаlysis rathеr than to еvolutionary Ьiologv Ьесausе ..momеnt of transition to thе spiritual'' was simply not opеn to еmpiriсal tЬе ..oЬsеrvation''(Popе Joannеs Pаulus II 1996, II 6). Not surprisingly, this statеmеnt has attrасtес]thе аttеntion of Сatholiс сommеntators. on thе morе rеaсtionary sidе, John MсСarthy oЬsеrvеdthat thе addrеss had gеnеratеd dismay and сonfusion among thе faithful. Hе thеrеfоrе workеd hаrd to minimizе any opеnnеssto еvolution that thе pгonounсеmеnt might foster Ьy thе introduсtion of a numЬеr of sеrpеlrtinеintеrprеtations and Ьy rеminding his rеadеrs that mеmЬеrs of thе Pontifiсal Aсadеmy of Sсiеnсеswеrе сhosеn rеgardlеssof геligious сrееd. By сontrast' in 1998 thе Vatiсan astronomеr Gеorgе V. Сoynе Warnlly еmЬrirсеd thе pope's announсеmеnt of evolution's faсtual status and wеnt on to urgе that ..сontinuous sinсе еvolution wаs tlrе mеthod of divirrе сrеаtion' thе idеa of сrеation'' Was thе Ьеst way to сonсеivе of thе еmеrgепсе of thе human spесiеs (Сoynе 1998, |60).

Thе ProtеstantМosaiс Protеstarrtrеsponsеsto еvolution Wеfе no lеss divеrsе.From thе еarliеstdays thеrе wеrе thosе who sеnsеd in еvolution thе mеthod of God's modus opеrandi in naturе. Angliсan pi1rson'novеlist' and Сhristian soсiаlist Сharlеs Kingslеy, for ехarrrplе'Was еnthusiаstiсabout the Оrigiп irnd wrotе to Daгwin tеlling him that although thе thеory mеant that hе must givе up many of ..just thе things hе Ьеliеvеd,it was as notaЬlе a сonсеption of Dеity, to Ьеliеvе thаt Hе сrеatеd primаl forms сapaЬlе of sеlf-dеvеlopmеnt''(Brrrkhardt and Smith 1985_2005, 7: 380). Simllarly, Frеdеriсk Tеmplе, latеr to Ьесomе arсhЬishop of CаntеrЬury, ехpгеssеdhis support as еarly as 1860, сontеnding that a world mаdе to makе itsеl{aсttrаllуепhirnсеdthе Сrеator's noЬilitу. To suсh figurеs, a univеrsе govегnеd Ьy lratural law was nrorе dignifying thaп

thе imagе of a divinе с. сontraSt' Samuеl WilЬе сally and philosophiсal ].860 mееting оf thе Е Franсis Oгpеn Мoггis, shirе, who authorеd а Dаrшinism (1869) and thought thаt Darwinisr thе Atlantiс thе сlеrgyп gllagеs in Boston Thеo сhoiсе еnсapsulatеdin Меntion too should bt doyеn of Amеriсan Prеs Dаrtuiпism?(l874) wit a judgmеnt on Darwin' lцtion itsеlf. Thе swееp of opinior Thе Еnglish Nonсonft Thomas R. Birks, tсlok Spеnсегian form, in boс Еuolutioп puЬlishеd in ity's ultimatе сhoiсе wa Selесtioп' His fеllorv сot ously sought to Dаrwtn ( l88З). Lеss spесulat who tоok up thе pгеs Univеrsity) in 1868, t< Allianсе that instеadof ophеrs would Ье Ьеttеr fеllow Sсotsmеn, thе thс aсh, and Hеnry Саldеr of thеistiс еvоlution. I insistеd in thе first dес: lution was simply anot This patсhwork of Рl around 1900 is matсh Werе сonnесtеd with vl own mеntor, thе Angli p r е s s е dе a r l y o p p o s i t i wiсk аnd thе Sсotti mathеmatiсal physiсis physiсal сomputations timе nееdеd for thе oр And infamously thе Pl1 rеspondеnt of Darwiir еvolution and rеliеd o

Еuolutioп апd Religion ld' any suggеstionthat thе human :ondеmnеdЬесausеof its impliсamilаr stipulation pеrtainеd to thе еd was Ьеyond thе rеaсh of еvoluL oЬligеsus to hold that souls arе : I I1 9 5 0 ' ч I3 6 ) . plеnаry assеmЬlyof thе Pontifiсal hе suЬjесtсlf еvolutiоn and its sig. эnt.Rесalling Pius ХII's еnсyсliсal :yond thе status of a mеrе hypothhuman Ьody had originatеd from atеd thе traditionаlсrеationist: origin of thе human soul in ordеr l iеap'' Ьеtwееn humanity and its еrs rotating around morality, сonnd spiгitual ехpеriеnсеwеrе dеlеn to еvolutionary Ьiology Ьесausе ' was simply not opеn to еmpiriсаl )6,\ 6). :traсtеdthе attеntion of Саtholiс idе, John МсСarthy oЬsеrvеd that :onfusion among thе faithful. Hе pеnnеssto еvolution that thе pro. i o n o f a n u m Ь е гo f s е r p е n t i n еi n rs that mеmЬеrs of thе Pontifiсal еss of rеligious сrееd. By сontrast, V. Сoynе warmly еmЬrасеd thе al status and wеnt on to urgе that ..сontinuous сrеation,thе idеa of of thе еmеrgеnсе of thе human

lеssdivеrsе.From thе еarliеst days ion thе mеthod of God's modus list' and Сhristian soсialist Сharlеs Ьout thе Оrigiп and wrotе to Darlеant that hе must givе up many of laЬlе a сonсеption of Dеity, to bе. е of sеlf-dеvеlopmеnt''(Burkhardt Frеdеriсk Tеmplе, latеr to Ьесomе supportas еarly as 1860, сontеndlly еnhanсеdthе Crеator's noЬility. tural lаw Was morе dignifying than

thе imagе of а divinе сonjurеr who mаgiсkеd nеw spесiеs into еxistеnсе. By .!7ilЬеrforсе сontrast, Samuеl thought that Darwin's thеory was Ьoth еmpiriсally and philosophiсally unsound and famously pourеd sсorn on it at thе 1860 mееting of thе British Assoсiation for thе Advanсеmеnt of Sсiеnсе. Franсis Orpеn Мorris' Viсtorian ornithologist and Angliсan rесtor in Yorkshirе' who authorеd a sеquеnсе of pamphlеts with titlеs likе Diffiсulties of Darшiпism (1'869) and The Demаnds of Dаrш,iпism oп Сredulitу Q890), thought that Darwinism dеsеrvеd only uttеr сontеmpt and dеrision. Aсross thе Atlantiс thе сlеrgyman Luthеr Traсy Townsеnd, who taught ЬiЬliсal languagеsin Boston Thеologiсal Sеminary, plaсеd Ьеforе his rеadеrs thе stark сhoiсе еnсapsulatеd in thе titlе of his traсt F,uolutioп or Сreаtioп (1896). Меntion too should Ье madе of thе Prinсеton thеologian Charlеs Hodgе, doyеn of Amеriсan PrеsЬytеriаns, who answеrеd his own quеstion in.Whаt ls Dаrtuiпism? (1874| with thе tеrsе quip ..It is athеism''' though this was morе a judgmеnt on Darwin's antitеlеologiсal stanсе than on thе prinсiplе of еvolution itsеlf. Thе swееp of opinion rеprеsеntеd hеrе сould Ье rеpеatеd many timеs ovеr. Thе Еnglish Nonсonformist and сofoundеr of thе Еvangеliсal Allianсе, Thomas R. Birks, took up thе сudgеls against еvolution, partiсularly in its Spеnсеrianform, in Ьooks likе Мodеrп Phуsiсаl Fаtаlism апd tbe Doctrinе of Еuolutioп puЬlishеd in \876. Thе Sсotsman.lfilliam Millеr fеlt that humanity'sultimatе сhoiсе was' to usе thе titlе of his 1897 volumе' God, or Nаturаl Selесtioп.His fеllow сountryman Hеnry Drummond' on thе othеr hand, vigorously sought to Darwinizе thеology inhis Nаturаl Lаш, iп the Spirituаl World (1883). Lеss spесulativе and morе traditionally Сalvinist, Jamеs МсСosh, who took up thе prеsidеnсy of thе Сollеgе of Nеw Jеrsеy (latеr Prinсеton Univеrsity) in 1868, told thе 1873 Nеw York mееting of thе Еvangеliсal Allianсе that instеad of dеnounсing the thеory of еvolution, Сhristian philosophеrswould Ье Ьеttеrеmployеd in ехpounding its rеligious dimеnsions. His fеllow Sсotsmеn' thе thеologians RoЬеrt Rainy, Gеorgе Мathеson, Jamеs lvеraсh, and Hеnry Сaldеrwood, all addеd thеir voiсеs in support of somе form of thеistiс еvolution. Latеr thе Amеriсan Baptist thеologian A. Н. Strong insistеdin thе first dесadе of thе twеntiеth сentury that thе prinсiplе of еvolution was simply anothеr namе for Сhrist. This patсhwork of Protеstant opinion from thе thеologians in thе dесadеs around 1900 is matсhеd Ьy thе pattеrn of rеsponsе аmong sсiеntists who Wеrесonnесtеd with various Protеstant dеnominations. In Britain Darwin's own mеntor, thе Angliсan сlеrgyman.naturalistJohn Stеvеns Неnslow, еxprеssеdеarly opposition' as did thе СamЬridgе gеologist Rеv. Adam Sеdgwiсk and thе Sсottish natural philosophеr David Brеwstеr. Thе Irish mathematiсalphysiсist at Glasgow, \й/illiamThomson (Lord Kеlvin), whosе physiсal сomputations of thе agе of thе еarth sееmеd to dеny Darwin thе timе nееdеd for the opеrations of natural sеlесtion, rеmainеd antagonistiс. And infamously thе Plymouth Brеthrеn naturalist Philip Hеnry Gossе, a сoгrеspondеntof Darwin and admirеr of lй/allaсе'was implaсaЬly opposеd to еvolutionand rеliеd on thе idеa hе put forward tn ОmphаIos (1857) (thе

З57

3.'8

Еuolutiсlп апd Rеligiсlп паuеl) thаt God had сrеatеd a maturе univеrsе with thе sеmGrееk word f<>r Ьlanсе of agе-proсhronism, as hе саllеd it. Aсross thе Atl:rntiс thе Swiss gеologist and physiсal gеographеr at РrеsЬytеriarrРrinсеtorr, Arnold Guyot, and his Сanadian сollntеrpart Jolrn Villiam Dawson, prеsidеnt of МсGill Univеrsity, also sеt thеir faсеs against Darwinism. In thе mid 1880s Guyot advoсatеd a kind of prе-Darwinian сlеvеlopmеntalismthat, in thе fashion of thе Sсottish stonеmason Hugh Мillеr, rеad thе gеologiсal еpoсhs into thе dаys of Gеnеsis, whilе Dawson Ьalkеd at Darwinisп]'s antitеlеologiсal stanсе. By сontrast thе Llarvard Ьotanist, Congrеgationalist, and сonfidant of Darwin Asa Gray foLrnd Ьoth Нodgе's and Dawson's oЬjесtions odd and workеd hard to fit еvolution into tеlеologiсal garmеnts Ьy arguing thаt it was rnistakеn tо rеstriсt thе idеа of dеsign to thе suddеn flashing of a Palеyitе wаtсh into ехistеnсе.Anothеr Сongrеgationlist' thе OЬеrlin gеologist Gеorgе Frеdеriсk Wright, also gavе еvolution his еndorsеmеnt in thе еarly 1880s' еvеn if hе wavеrеd lаtеr in lifе, i.rndwеnt so far as to draw a sеt of rеlling analogiеs Ьеtwееn Calvinism and Darwinism, сonсluding that Darwinism was ..the Сalvinistiс intеrprеtation of naturе'' (\Х/right1882, 255). othеr suppсlrtivе сommеntariеs. though with varying dеgrееs of еnthusiasпl' wеrе foгthсoming from suсh sсiеntifiс praсtitionеrs as thе Сalifornia gеologist Josеph LеСontе, thе Yalе minеralogist Jamеs Dana' thе Miсhigan .sИinсhеll, gеoIogistAlехandеr and thе Prinсеton сlеrgyman.ЬiologistGеorgе Мaсloskiе' Indееd, figurеs likе thеsе did a good dеal to kееp linеs of сommuniсation opеn bеtwееn spесialist sсiеnсе and rеadеrs of dеnominational magаzinеs. A с a t a l o g o f s u с h p a r t i с u l a r i t i е sс o u l d Ь е е l a Ь o r a t е da d l i Ь i t u m , Ь u t a s a n ovеrall gеrrеrаlization' most Protеstant thinkеrs Ьеliеvеd that еvolution сould Ье еmЬraсеd without aЬandoning doсtrinal еssеntials.Thе majority found ways of aссommodating thеir thеology to morе or lеss rеvisеd vеrsiorrs of еvolutionary thеory. As wеll as сhallеnging widеsprеad assumptions of systеlтliсhostilitiеs Ьеtwееrtеvolutiol-land rеligion, this trаjесtory sеrvеs to сall attеntion to a numЬеr of sееming inсongruitiеs. Thus numЬеrеd among thе writеrs of Thе Fuпdаmeпtаls, a sеquеnсeof 72 pamphlеts i s s u е d Ь е t w е е n 1 9 1 0 а n d 1 9 1 5 t h a t g a v е v o i с е t o е а r l . vF u r - r d a m е n t a l i s m , Wеrе sеvеral writеrs, inсluding G. F. Wright and thе Sсottish thеologian Jamеs Orr, who advoсatеd еvolution in onе form or anothеr. There is also .Warfiеld, thе саsе of thе Prinсеton thеologian B. B. сustodian of thе сonfеssioгral standards of trаditional Саlvinism and rnodеrn aгсhitесt of thе doсtrinе of biЬliсal inеrгanсy, a mainstay of thе Amеriсan Fundаmеntalist .!Иarfiеld movеmеnt. Brought up on a Kеntuсky stoсk farm' knеw firsthаnd aЬout inhегitеd variation irr animal Ьrееding arrd latеr musеd that hе was аlrеady a ..Darwinian of thе purеst watеr'' bеforе thе сoming of Jamеs МсСosh to Prinсеton (\Wаrfiеld \976, 652). In 1915 hе сlаimеd that Сalvin's doсtrinе of сrеаtion was in faсt a ,.vегy purе еvolutionary sсhеmе'' ( W a r f i е l d1 9 1 5 , 2 0 9 \ . Dеspitе this plurаlism aсross thе dеnominational spесtrum' сеrtain sесtarian strands in Protеstantism rепrainеd staunсhly rеsistant to Darwinian

infiltration. To a сon sсiеnсе сan Ье traсеd tist Gеorgе MсСrеаd Weаkеst Poiпt iп the His flood gеology ех apologist, Еllеn \Х/hit litеralist intеrprеtatio alonе, and hе rесеivе sеlf-stylеd rеsеarсh sс tor.William Bеll Rilеу was also forthсomin1 сratiс сandidatе for paсifist, whosе fеars Gеrmaniс militarism thе сеlеЬrаtеd Sсopеs ron ехtraordinairе сor Darrow. Of сourse, tt absеnt from thеsе оth phlеt titlеd Poisoпiпg еvolutionism togеthе еvolutionary transfor and politiсal.In Brita ship of AmЬrosе Flеr vеrsity Collеgе Londс allowеd for thе poss Indееd, in Flеming's t сrеation of thе ЬiЬliс сal findings2 a movе t

wrong way. Whatеvеr thе sourс motion dесlinеd fair though it promptеd А Historу of Noп-euс tеnt and up.to-dаtе lil aЬеyanсе until thе 19. Ьibliсal thеоlogian Jo Ьесamе thе foundаtio Geпesis Flood. |t |im аnd rеassеrtеdсrеatiс its various еdцсаtion еlsеwhеrе in this volr polеmiсs and intеrnа day сrеationism has d ally' In faсt, thе th сontinuеd to Ье dеfеn dеnominational rang

Еuolutioп апd Rеligioп l a maturе univеrsе with thе sеm, Aсross thе Atlantiс thе Swiss gе_ tеriаn Prinсeton, Arnold Guyot, Lm Dawson, prеsidеrrtof MсGill winism. In thе nrid 1880s Guyot lmеntalismthat, in thе fashion of d thе gеologiсal еpoсhs into thе at Darwinism's antitеlеologiсal Сongrеgationalist,and сonfidant 's and Dawson's oЬiесtions odd llogiсal garmеnts Ьy arguing that sign to thе srrddеn flaslring of a :lgrеgationlist, thе ()Ьеrlin gеolo:volutionhis еndorsеmеnt in thе , and wеnt so far аs to dfaw a sеt Darwinism, сonсluding that Dart o f n a t u r е ' '( w r i g h t 1 8 8 2 ' 2 5 5 ) . with varying dеgгееs of еnthusiiс praсtitionеrsas thе Сalifornia LlogistJamеs Dаna' thе Мiсhigan сеton сlеrgyrnan-ЬiolоgistGеorgе ' good dеal to kееp linеs of сom:е and rеadеrs of dеnоminational е еlaЬoratеdad liЬitum' but as an гhinkеrs Ьеliеvеd that еvolution l o с t r i n а lе s s е n t i a l sT. h е m а j o r i t y logy to morе or lеss rеvisеd vеrсhallеnging widеsprеаd assumрr t i o n a n d г е l i g i o n ,t h i s t r а j е с t o г y эеminginсongruitiеs. Thus num. зtаls,a sеquеnсеof 12 pamphlеts : voiсе to еarly Fundamеntalism, ight and thе Sсottish thеologian nе form or anothеr. Thеrе is also Warfiеld,сustodian of thе сonfеsand modеrn arсhitесt of thе doсlf thе Aпrеriсirr-r}-undamеntalist сk farm, Warfiеld knеw firsthand ling and latеr пrusеd that hе was еr'' Ьеforе thе сoming of Jamеs 652). In 1915 hе сlaimеd that ..vеrypurе еvolutionary sсhеmе'' rlinationaI spесtrllm' сеrtain sесstaunсh[,vrеsistant to Darwinian

infiltration. Tо a сonsidеraЬlе dеgrее thе еmеrgеnсе of modеfn сrеation sсiеnсесan Ье trасеd to thе еnеrgеtiс aсtivitiеs of thе Sеvеnth-Dаy Advеntist Gеorgе МсСrе:rdy Priсе, author in ] 906 of Illogiсаl Geologу: Tbе Wеаkеst Point in the Еuolиtioп Theorу and irr 192З of Thе Nеш Gеologу' His flood gеоlogy ехprеssеd thе -lr4osaiсsсiеnсе of thе movеmеnt's сhiеf apologist, Еllеn Vhitе, whosе doсtrinе of thе SaЬЬath was groundеd in a litеralist intеrprеtatiоn of thе сrеation narrativе. Priсе, of сoursе' wаs not alonе, and hе rесеivеd еnсoriragеmеntfrom thе PrеsЬyterian ministеr and sеlf-stylеdrеsеarсh sсiеntist Harry Rimmеr and thе ]V1innеsotaBaptist pаs.William Bell Rilеy. Support, though from a diffеrеnt idеologiсal staЬlе, tor was also forthсoming from William Jеnnings Bryаn' thrее timеs Dеmoсratiс сandidatе for thе prеsidеnсy of thе Unitеd Statеs and сommittеd paсifist' whosе fеаrs about thе sееming allianсе Ьеtwееn Darwinism and Gеrmаniс militarism еnсouragеd him to tirkе up thе proseсution's саsе in thе сеlеЬratеdSсopеs trial of |925.|t еarnеd for him thе rеputation of moron ехtraordinairе сourtеsy of thе polеmiсs of his fеisty opponеnt' Сlarеnсе Darrow. of сoursе, this is not to say that mattеrs of politiсal idеology wеre aЬsеntfrom thеsе othеr сontrovеrsialists.Priсе, for instanсе, issuеd a pamphlеt titlеd Poisoпiпg Demoсrасу 1921) in whiсh hе nеttеd soсialism and еvolutionism togеthег as thе mainspring of modеrn-day ills. His loathing of еvolutionary trаnsfortnisnr was thtls mr-rlridirrrеrrsional-biЬliсal,sсiеntifiс, and politiсal. In Britain thе Еvolution Protеst Мovеmеnt' undеr thе lеadеrship of AmЬrosе Flеming, FRS, profеssor of еlесtriсal tесhnology at Univеrsity Сollеgе Lоndon, laсkеd thе vitriol of its Amеriсan сountеrpart and allowеd for thе possiЬility of somе divinеly guidеd еvolutionary сhangе. Indееd,in Flеming's own сasе hе was еvеn prеparеd to rеаd aspесts of thе сrеаtion of thе ЬiЬliсal Adam in thе light of various palеoanthropologiсal findings, a movе that сertainly ruЬЬed thе anatomist Arthur Kеith thе wгong Way. !Иhatеvеr thе sourсеs of thеsе sеntimеnts' this flurry of сrеationist сommotion dесlinеd fairly dramatiсally in thе yеars aftеr thе Sсopеs trial, though it prornptеd thе puЬliсation of Е. T. Brеwster's 1,927 Сrеаtioп: А Historу of Noп-еuolиtioпаrу Thеoriеs to Ьalanсе thе ..amplе and сompе. tеnt and up-to-datе litеraturе of Еvolution.'' Сrеationist agitation Wеnt into abеyanсеuntil thе 1950s whеn thе hydrauliс еngineerНеnry Morris and thе biЬliсal thеologiаn John WhitсomЬ joinеd forсеs to produсе in 196l what Ьесamеthе foundational tеxt of thе modеrn сrеation sсiеnсеmovеmеnt' Тl2e Genеsis Flood. It limitеd gеoiogiсal histoгy to no morе thаn 10,000 yеагs and rеassеrtеdсrеation in six litеral dаvs. Thе tгaiесtory of this movеmеnt' its various еduсational maсhinations, аnd its lеgal Stratagеmsarе сhartеd еlsеwhеrеin this volumе. It suffiсеs hеrе to add that dеspitе its аggrеssivе polеmiсsand intеrnational suссеss' it would Ье mistakеn to think that siхday сrеationismhas dominatеd сonsеrvativеProtеstant thought morе gеnеrally. In faсt' thе thеory of еvolution, in onе vеrsion or аnothеr, has сontinuеdto Ье dеfеndеd Ьy Protеstant thеologiаns and sсiеntistsaсross thе dеnominationаlrarrgе.

З59

З60

Еuolиtioп аnd Reliяiсlп

In thе Light of Меnorah and Qur'an Rеligious rеsponsеs to еvolutionary thеory wеrе oftеn Ьound up with Ьroadеr issuеs that сonfrontеd thеologiсal сulturеs and faith сommunitiеs, not lеast qшеstions of how to еngagе with a thrеatеning wider soсiеty or how to rеtаin or rеfashion idеntity in the faсе of еxtramural сhallеngеs.Jеwish dеЬatеsaЬout Daгwinism in latе ninеtееnth-сеntury Amеriсa arе illustrativе, for thеsе wеrе part and parсеl of a suitе of dеliЬеrations on thе futurе shаpе that Amеriсan Judaism should takе (Swеtlitz 1,999).Traditionalist, Мodеratе Rеform, and Radiсal Rеform raЬbis еaсh had a stakе in how thе Jеwish сommunity should rеspond. on thе radiсal wing еvolution was еmЬraсеd Ьесausеit сould Ье moЬilizеd to undеrwritе progrеssivism and tгansformation. Thus thе rеadеrs of Kaufmann Kohlеr's various pronounсеmеnts during thе 1870s and 1880s lеarnеd that еvolution appliеd to thе spiritual rеalm and that Jеwish ritual and сеrеmonial nееdеd to Ье rеfashionеd to kееp in stеp with modеrn sсiеnсе. To him and othеrs likе him, еvolutionary dеvеlopmеnt сonfirmеd thе prinсiplе of progrеssivе rеvеlаtion; adaptation to thе prеvailing еnvironmеnt appliеd to organiс and rеligious сommunitiеs alikе. From thе samе thеologiсal staЬlе Josеph Krauskopf, in a sеquеnсе of lесturеs ttt|edЕuolиtioп аnd Judаism and puЬlishеd in 1887, rеadily appliеd еvolution to thе growth of rеligion, thе tеxtual history of sсripturе' primitivе Soсiеty' thе idеa of God, and thе dеvеlopmеnt of Jеwish worship. Traditionalists, Ьy сontrast' еithеr rеjесtеd Darwinism or ln somе сasеs moЬilizеd it to support traditional Jеwish thеology. on thе onе hand, Samuеl М. Isaaсs usеd his position as еditor of thе letuish Меsseпger to launсh at. taсks on еvolution, whilе AЬraham dе Sola' a Сanadian immigrant, mаrshaled thе сritiсisms of thе Montrеal gеologist John William Dawson to attaсk thе thеory. Thomas Mitсhеll, an advoсatе of thе viеw that God had сrеatеd thе world in siх 24-hour days, told readеrs of his 1887 artiсlе..Еvo. lution and Judaism'' for Мeпorаb that thеrе was not a shrеd of еvidеnсеfor human antiquity or еvolutionary сhangе. On thе othеr hand, the traditionalist еditors of tЬe Amеriсап Hebrеш' a good numЬеr of whom wеrе trainеd in sсiеnсе or mеdiсinе, workеd to сultivatе a thеistiс vеrsion of еvolution along thе linеs of Asa Gray. Traditionalists too appеalеd to thе gradualism of еvolution to opposе rapid сhangе and any swееping ovеrthrow of inhеritеd institutions. Thе tеnaсious еnduranсе ovеr сountlеss gеnеrations of traditiоnal сеrеmonial tеstifiеd to its valuе in thе Jеwish strugglе for survival against i n n u m е r а Ь l еa d v е r s i t i е s . Intеrnal rivalriеs thus did muсh to govеrn raЬЬiniс еnсountеrs with еvolution еvеn though pro- and anti-Darwinian sеntimеnts nеvеr dirесtly mappеd onto thе сommunity's vаrious faсtions. This mеans that the sсiеntifiс dimеnsions of еvolutionary thеory wеrе rarеly addrеssеd;rеsponsеs wеrе mеdiatеd through сonсеrns aЬout thе supposеd influеnсе that matеrialism had on lowеring synagoguе attеndanсе' on еvolution's impliсations for thе naturе of mind and morality, and on what advoсatеs Ьеliеvеd its aссеptanсе еntailеd

for rеligious institutions aл Ьatеs wаs thе nаturе of Jud Somеthing of thе sаmе s though in thе Islamiс сasе а thе Qur'аn has mеant that а lеss, Islamiс support for еv for еxamplе, has сlaimеd t Islam, whilе thе LеЬanesеs tirеly сompatiЬlе with Qur' Аfzaa| (7996)' who likеwis from thе Holy Qur'an itsеlf winism and еvolution. The limitеd appliсaЬility of nat ..fits pеrfесtly in thе ovеrall Book.,' Indееd, dеploying tl an еvolutionary aссount of mеnt to natural proсеssеs. сrеation. In this movе lnсr( еrесtus' and so on-dеvеlo: lесtеd a singlе pair-a malе itual souls." Not surprising aссounts of figurеs likе Tеil] Dеspitе thеsе irеniс еffс from writеrs likе T. Н. Jan: warrant and is promotеd haЬuddin Nadvi issuеd a rl сrеation of Adam, whilе Aс i n с o r p o r a t е dm а t t е ro r i g i n haps thе most influеntialIs еdly an еminеnt Turkish r antiеvolutionary traсts (likе that his opponеnts сlaim tl of writеrs. In any сasе,in t} ..dishonеstphilosoph at thе siс valuеs on whiсh thе sta thе traсt urgеs, providеd a l еntifiс status' thеrеЬy еxpl in natural history. In anot Ьrought to humаnity,'' YaI saсrе to thе malign influеnс winism on figurеs likе Stal (Yahya 2001). Translatеd Yahya mind-sеt' partiсular с r е a t i o n i s tЬ o o k s Ь е с o m i n tain plaсеs (Koеnig 2001). numbег of TuгkishDeгwi

Еuolution аnd Religioп

n еrе oftеn Ьound up with Ьroadеr rnd faith сommunitiеs, not lеast r g w i d е r s o с i е t yo r h o w t o r е t a i n сhallеngеs.Jеwish dеbatеs aЬout сa arе illustrativе, for thеsе wеrе r thе futurе shapе that Amеriсan 'ionalist,Modеratе Rеform, and lw thе Jеwish сommunity should :mЬrасеdbесausеit сould Ье molsformation.Thus thе rеadеrs of ts during thе 1870s and 1880s 'lal rеalm and that Jеwish ritual <ееpin stеp with modеrn sсiеnсе. еlopmеntсonfirmеd thе prinсiplе prеvаilingеnvironmеnt appliеd From thе samе thеologiсal stаЬlе rit|edЕuolution апd Judаism and )n to thе growth of rеligion, thе l, thе idеa of God, and thе dеvеlеd Darwinism or in somе сasеs еology.on thе onе hand, Samuеl : Jetuish Меssеngеr to launсh atLa,a Сanadian immigrant' mar. logist John !Иilliam Dawson to ,,oсatеof thе viеw that God had ..Еvorеadеrsof his 1887 artiсlе 3 was not a shrеd оf еvidеnсе for n thе othеr hand' thе traditionalnumЬеrof whom wеrе trainеd in hеistiс vеrsion of еvolution along to thе gradualism of еvo>pеalеd ping ovеrthrow of inhеritеd instirntlеssgеnеrations of traditional .ish strugglеfor survival against r rabЬiniс еnсountеrs with еvolu;еntimеntsnеvеr dirесtly mappеd s mеans that thе sсiеntifiс dimеnJrеssеd;rеsponsеswеrе mеdiatеd ,nсеthat matеrialism had on low's impliсatiоns for thе naturе of s Ьеliеvеd its aссеDtanсе еntailеd

for rеligiоus institutions and сustoms. \й/hat was oftеn at stakе in thesе dеbatеswas thе naturе of Judaism itsеlf. Somеthing of thе samе spесtrum of rеaсtions is also disсеrniЬlе in Islam, though in thе Islamiс сasе a rathеr morе prеvailing litеralistiс hеrmеnеutiс of thе Qur'аn has mеant thаt advoсatеs of еvolution arе lеss сommon. Nеvеrthеlеss'Islamiс support for еvolution is not еntirеly aЬsеnt. Мuhammad IqЬal, for ехamplе, has сlaimеd that thе idеa of еvolution originatеd in mеdiеval Islam, whilе thе LеЬanеsе sсholar Нossеin al-Jisr insists that thе thеory is еntirely сompatiЬlе with Qur'aniс thеology (Majid 2002).In thе сasе of Ahmеd tfzaa| (7996), who likеwisе сontеnds that ..thе thеory of еvolution sprouts from thе Holy Qur'an itsеlf,'' a сruсial distinсtion is prosесutеd Ьеtwееn Darwinism and еvolution. Thе formеr hе finds unaссеptaЬlе on aссount of thе limitеd appliсability of nаtural sеlесtion, whеrеas thе prinсiplе of еvolution ..fitspеrfeсtly in thе ovеrall sсhеmе of God's сrеation as dеsсгiЬеd in thе Holy Book.'' Indееd' dеploying thе standard soul-Ьody dualism, Аfzaa| arguеs for an еvolutionary aссount of thе human spесiеs that alloсatеs physiсal dеvеlopmеnt to naturаl proсеssеs and thе еmеrgеnсе of sеlf.сonsсiousnеss to divinе сrеation. In this movе inсrеasingly humanoid forms-Homo hаbilis, Homo еrесtus,and so on-dеvеlopеd to a point whеrе ..Almighty Allah (S!ИТ) sеlесtеda singlе pair-a malе and a fеmalе-and еndowеd thеm with thеir spiritual souls.'' Not surprisinglу, Аfzaa| found inspiration in thе antimесhanistiс aссountsof figurеs likе Tеilhard dе Сhardin and Hеnri Bеrgson. Dеspitе thеsе irеniс еfforts, vigorous opposition has Ьееn forthсoming from writеrs likе T. H. JanaЬi who сlaim that еvolution is without еmpiriсal warrant and is promotеd for soсial and politiсal rеasons. Similarly, Shahabuddin Nadvi issuеd а rеfutation of еvolution in his 1987 aссount of thе сrеation of Adаm, whilе Adеm Tatli's Еuolutioп: А Bапkrupt Theorу 0990) inсorporatеd mattеr originally prеsеntеd to thе Turkish govеrnmеnt. But pеrhaps thе most influential Islamiс сritiс of Darwinism is Harun Yahya, rеportеdly an еminеnt Turkish sсholar, who has Ьееn so prolifiс in produсing antiеvolutionarytraсts (\tkeWbу Dаrluiпism ls Inсompаtible шith thе Qur'ап) that his opponеnts сlaim that thе works arе aсtually thе produсt of a group of writеrs. In any сasе, in tЬe \999 Ьook Thе Еuolutioп Dесeit Yahya hit out at thе ..dishonеstphilosophy'' of ..matеrialism''that ..sееksto aЬolish thе Ьa. siс vаluеs on whiсh thе statе and soсiеty rеst'' (Yahya 1999, 7). Daгwinism, thе traсt urgеs, providеd a mythiс foundation for matеrialism's сlaims to sсiеntifiс status, thеrеЬy ехplaining why Мarx rootеd dialесtiсаl matеrialism in natural history. In anothеr 2001 rеhеarsal of ..thе disastеrs Darwinism Ьrought to humаnity,'' Yahya has attriЬutеd war, povеrty' pain, and massaсrеto thе malign influеnсе of ..thе selfish and pitilеss world viеw'' of Darwinism on figurеs likе Stalin' Trotsky, Мao, Pol Pot, Нitlеr' and Mussolini (Yahya 2001). Translatеd into mаny languagеs' thе output of thе Harun Yahya mind-sеt, partiсularly in Turkеy, has Ьееn rеportеd as immеnsе, with сrеationistЬooks Ьесoming morе influеntial than standагd tехtЬooks in сеrtain plaсеs (Koеnig 2001). To Ье surе, thеsе movеs havе Ьееn rеsistеd Ьy a numbеr of Turkish Darwinians, notaЬly thе Ьiologist Aykut Kеnсе and thе

З61

З62

Еuolution аnd Rеligion mеdiсаl gеnеtiсist Isik Bбkеsoy. But marshaling support for Darwinian еvolution has provеd diffiсult in a сontехt whеrе politiсal fоrсеs havе fostеrеd thе tеaсhing of сrеationism in sсhools and whеrе dirесt support has Ьееn providеd Ьy Amеriсan Protеstant сrеationists(Еdis 1994).

Rесuгring Thеmеs Various historiсal modеls havе Ьееn сanvassеd in thе attеmpt to gеt a handlе on thе rеlations Ьеtwееn sсiеnсе and rеligion. Our travеls thus far сonfirm that any simplе portrayal of thе rеlations Ьеtwееnеvolutionary thеory and rеligious Ьеliеf is doomеd to fall foul of thе mеssinеssof history, Ьut a numЬеr of pеrsistеnt thеmеs havе rесurrеd, alЬеit in diffеrеnt wаys in diffеrеnt sеttings. Quеstions of sсriptural hermeпeutiсs havе routinеly surfaсеd in disсussions of еvolution. Somе adhеrе to a litеralistiс еxegеsis of сrеation narrativеs, whilе thosе who arе intеrеstеd in сonсordism havе strеssеd thе rolе of mеtaphor and сultural сontеxt in thе intеrprеtation of partiсular statеmеnts. Thosе who arе willing to rеlеgatе thе Мosаiс narrativе to thе rеalm of primitivе mythology havе Ьееn еngagеd no lеss in a hеrmеnеutiс undеrtaking. Еithеr Way' quеstions of ехеgеsis havе pеrsistеntly oЬtгudеd. Philip Hеnry Gossе's wholе systеm of proсhronism was dеsignеd to prеsеrvе thе litеral aссuraсy of thе BiЬlе's timеsсalе.By сontrast, thе Oriеntal and ЬiЬliсal sсholar \и. H. Grееn rеliеvеd сеrtain strands of соnsеrvativе Рrotеstantism of thе Ьurdеn of Usshеr-typе сhronology (whiсh famously datеd thе world's origin to 4004 B.с.Е.) whеn hе dеmonstratеdin 1890 that old Tеstamеnt gеnеalogiеs сould not Ье rеliеd on to datе primеval timе on aссount of thеir stratеgiс omissions from thе rесords. That gavе somе thеistiс еvolutionists thе hеrmеnеutiс room thеy nееdеd. Again, thе Сatholiс writеr Dorlodot dеvotеd сonsidеraЬlе spaсе to еluсidating Сatholiс thеoriеs of inspiration in ordеr to allow for his сonviсtion that thе thought-forms of sсгipturе wеrе aссommodatеd to thе сultural сonditions of thе timе. And thе Islamiс еvolutionist Ahmеd Аfzaa| urgеd thе lеgitimaсy of еxplaining ..thе rеlеvant Qur'aniс vеrsеs in tеrms of a mеtaphor or paraЬlе'' and spokе of ..thе Qur'aniс lеgend of thе .Fall''' (t{zaa| 1996). In onе Way or anothеr' еvolution thеory has pеrsistеntly rесallеd attеntion to hеrmеnеutiс mattеrs in thе intеrprеtation of anсiеnt saсrеd tехts. From its еarliеst days Darwin's thеory сonfrontеd hеad-on thе issuе of tеlе' ologу. As Darwin himsеlf put it at onе point, ..Thе old аrgumеnt from dеsign in nаturе, as givеn by Palеy whiсh fоrmеrly sееmеdto mе so сonсlusivе' fails, now that thе law of natural selесtionhas Ьееn disсovеrеd'' (Darwin 1888, 1: 309). Thе сonsеquеnсеsWеrе potеntially monumеntal, for natural thеology had undеrsсorеd thе fundamеntally moral сharaсtеr of naturе' еnthusing Ьеliеvеrs, сurЬing sесtarian tеnsions' end inspiring mеn and womеn to study .!0.hig, God's handiwork. !Иhеthеr from thе pеn of \Х/illiam Palеy, a modеratе whosе Nаturаl Thеology (1802) was dеvourеd Ьy Darwin, or in thе multivolumе Bridgeшаter Trеаtises (1833_1836), whiсh sеt out to dеmonstratе

divinе wisdom and powеr wrotе inquiry intо thе ni vеrsе. In rеsponsе' numе tеlеologiсally. In gеnеral, sion had a morе diffiсult plans and thе opеrationsс thusiast for thе way Argyl divinе wisdom morе in h. Thе Dutсh Сalvinist, fоun o f - t h е - с е n t u r yp г i m е m i n zoologist Jan Lеvеr (195 whiсh сonсеivеd of natur сoursе' this doеs not mеa tirеly disappеarеd. Thе nt surfaсеd in rесеnt timеs st has Ьееn сallеd irrеduсiЬl an all-or-nothing variеty l ations on whiсh natural sс i n i t s s t а t i s t i с a lw i z a r d r y ' pliсations of Darwin fоr . thеrе сontinuеs to bе philс thе diffеrеnt positions ad< tinga (199 l),who dеfеnds Еrnan MсMullin (1991I,

ural law. Thе faсt that s o u n d i n g v o с a b u l a r yu r g i Ь y . t r i а l a n d е г г o г . 'г h а ti t .loo1 Ьy snеaking through t е i n s i n o r d е г t o i m p r o v еi wholе issuе (Grееne 1989 Aсross thе rеligious ran thе spесtrе of mаteriаlisn that еvolution is еrесtеdс moral natцrе and has сu various strаnds havе also l for instanсе, thе Catholiс A Studу of Vitаlism апd outlook of thе ехpеrimеn thе antirеduсtionism ехpr and P. G. Tait, whiсh first John Тyndall's infamous сlinations, Windlе Was at mattеr' and hе rеmainеd t сhaniсal univеrsе. By сon sесondary саusеs-that G f o r m o f m a t е r i а l i s mс o n s i

Еuolutioп аnd Religiсlп ling support for Darwinran еvo. rе politiсal forсеs havе fostеrеd rеrеdirесtsupport has Ьееn prodts 1994).

:d in thе attеmpt to gеt a handlе our travеlsthus far сonfirm that еvolutionarythеory and rеligious lf history' Ьut a numЬеr of pеrsisways in diffеrеnt sеttings. r o u r i n е l ys u r f a с е di n d i s с u s s i o n s ехеgеsisof сrеation naгrativеS' n havе strеssеdthе rolе оf mеtatation of partiсular statеmеnts. с narrativе to thе rеalm of prim. ; in a hеrmеnеutiс undеrtaking. sistеntly oЬtrudеd. Philip Неnry еsignеdto prеsеrvе thе litеral aсthе oriеntal and ЬiЬliсal sсholar lnsеrvativеРrotеstantism of thе rmously datеd thе world's origin ]90 that old Tеstamеnt gеnеalor i m еo n a с с o u n to f t h е i r s t r a t е g i с somе thеistiс еvolutionists thе ]atholiс writеr Dorlodot dеvotеd hеoriеsof inspiration in ordеr to lrms of sсripturе Wеrе aссommonе. And thе Islamiс еvolutionist ..thе rеlеvant 'plaining Qur'aniс ..thе nd spokе of Qur'aniс lеgеnd )r anothеr' еvolution thеory has iс mаttеrs in thе intеrprеtation of rfrontеd hеad-on thе issuе of telе..Thе old argumеnt from dеsign t, sееmеdto mе so сonсlusivе' fails, : е nd i s с o v е r е d '(' D a r w i n 1 8 8 8 , 1 : lonumеntal, for natural thеology :haгaсtеrof naturе, еnthusing bеpiring mеn and womеn to study !Иilliam Pаlеy, a modеratе.Whig, urеd Ьy Darwin, or in thе multi. i). whiсh sеt out to dеmonstratе

divinе wisdom and powеr in сrеation, thе natural thеology еntеrprisеundеrwrotе inquiry into thе natural ordеr. Darwin dеstaЬilizеd this wholе univеrse. In rеsponsе' numеrous writеrs workеd hard to intеrprеt еvolution tеlеologiсally.In gеnеral,thosе who wеrе still еnthusiastiсaЬout Palеy's vеrsion had a morе diffiсult task than thosе who found dеsign in arсhеtypal plans and thе opеrations of natural law. Thus Jamеs МсСosh, alrеаdy an еnthusiastfor thе way Argyll's Тbе Reigп of I-аtu rеloсatеd divinе dеsign, found divinе wisdom morе in homologiсal struсturеs than in spесifiс adаptаtions. Thе Dutсh Сalvinist' foundеr of thе Frее Univеrsity of Amstеrdam, and turnof-thе-сеntury primе ministеr AЬrаham Kuypеr аnd latеr dеvotееs likе thе zoоlogist Jan Lеvеr (1958, 229) spoke of ..divinе еvolutionistiс сrеation''' whiсh сonсеivеd of naturе unfolding aссording to a prеdеtеrminеdplan. of сoursе'this doеs not mеan that advoсatеs of Palеy's mесhaniсal vеrsion еntirеly disappеarеd. Thе nеoсrеаtionist Intеlligеnt Dеsign movеmеnt that has surfaсеdin rесеnt timеs sееks to idеntify ехtеrnally dеrivеd purposе in what has Ьееn сallеd iгrеduсiЬlесomplехity, namеly, сеrtain Ьiologiсal systеmsof an all-or-nothingvariеty whose funсtions сannot Ье rеduсеd to simplеr opеrations on whiсh natural sеlесtion сan work. In its соnсеptual struсturе, if not in its statistiсalrwizardrу,this rеads likе Palеy rеdivivus. In аny сasе thе impliсationsof Darwin for dеsign havе геmainеd a kеy arеna of dеЬate. That thеrесontinuеsto Ье philosophiсal milеagе in this wholе mattеr is сlеar from thе diffеrеntpositions adoptеd Ьy suсh еminеnt philosophеrs as Alvin Plan. tinga(1991),whodеfеndsdivine intеrvеntionismin thе history of naturе, and Еrnan MсМullin (1991)' who inсlinеs moге toward God aсting through natural law. Thе faсt that Ьiologists havе frеquеntly tradеd in tеlеologiсal. soundingvoсaЬulary urging ..that еvolution is .opportunistiс', that it proсееds Ьy .trialand еrror', that it rеaсhеs.dеad еnds' or aссomplishеs.Ьrеakthroughs' by snеakingthrough .loopholеs', or that natural sеlесtion .сan rеmodеl protеinsin ordеr to improvе intеraсtions' '' adds yеt furthеr сompliсations to thе w h o l еi s s u е( G r е е n е1 9 8 9 ' 4 0 8 ) . Aсross thе rеligious rangе opponеnts of Darwinism havе Ьееn hauntеd Ьy thе spесtrе of mаteriаlisz. Islamiс opposition springs in part from a sеnsе that еvolution is еrесtеdon a matеrialist сrееd that dесonstruсtshumanity's .Wеstеrn moral naturе and has сultivatеd a dесadеnt сulturе. Сhristians of variousstrandshavе also Ьееn trouЬlеd Ьy similar сonсеrns.Bеrtram.!Иindlе, for instanсе' thе Catholiс advoсаtе of еvolution and author of Wbаt ls Life? А Studу of Vitаlism апd Neo-uitаlism (\908), ехprеssеd sympаthy for thе outlook of thе ехpеrimеntal physiсist and spiritualist Olivеr Lodgе and for thе antirеduсtionism ехprеssеd tn The Uпseeп Uпiuerse of Bаlfouг Stеwart and P. G. Tait, whiсh first appеarеd anonymously in 1875 immеdiatеly aftеr John Tyndall's infamous Bеlfаst addrеss. An еvolutionist of Lamarсkian inсlinations,Windlе was attraсtеd to thе idеa of a Vital Powеr that anrmatеs matter'and hе rеmainеd сhary of sсiеntifiс inсlinations toward a purеly mесhaniсal univеrsе. By сontrast, numеrous writеrs havе usеd thе doсtrinе of sесondaryсausеs-that God works through natural agеnсiеs-to arguе for a .lfarfiеld, form of matеrialism сonsistеnt with thе Judеo-Сhristian hеritagе. for

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З64 Еuolиtioп аnd Rеligion еxilmplе, insisсеd that,,a сomplеtе systеm of naturаl сausation'' was еntirеly ..tеlеologiсalsystеm impliеs a сomсonsistеnt with tеlеology and tlrat еvеry .сauso-mесhaniсal' plеtе explanation as its instrrrmеnt'' (quotеd in Livingstonе and Noll 2000,301). Diffеrеnt though all thеsе rеsponsеsundouЬtеdly arе, thеy Ьеar witnеss to matеrialism as a rесurring loсus of dеЬatе. Сlosеly сonnесtеd with thеsе сonсеrns is a sеt сlf quеstionsthаt сongrеgatе aror.rndthе impliсzrtions of еvolutiorr for thе псltLlrеаnd morаlitу of the hшmап аgeпt. Vaгious stanсеs havе Ьееn adoptеd on thе issuе of whеthеr human Ьеings bаuе sods or arс souls. Somе havе optеd for thе viеw that thе soul is always thе rеsult of an aсt of divinе сrеation. Thus thе Сatholiс еvolutionist Еrnеst Меssеngеr oЬsеrvеd in his 1931 ассount Еuolutioп апd Theol. ..no ogу tЬ,at Cаtholiс thеologian or philosophеr сould possibly allow that thе spiritual soul of man has еvolvеd from a brrrtesoul, muсh lеss from inorganiс mattеr. Thе soul is immatеrial, and сan only сomе into ехistеnсеЬy a dirесt aсt of сrеation'' (Меssеngеr 19З\, 14З)' Othеrs havе thought that thе idеа of thе soul еmеrging in somе way from еarliеr forеЬеаrsis еntiгеlyсompаtiЬlе with thеir thеology. As for thе еthiсal rеpеrсussionsof Darwinism, somе havе гесoilеd at thе suggеstionthat moral sеnsiЬilitу has Ьееn shapеd Ьy thе impеrativеs of a strugglе for survival. In suсh a sсеnario, as \William ..Grеat Сommonеr,'' madе сlеar, thеrе is no rеason to Jеnnings Bryаn, thе еxpесt humans dеsсеndеd from animals to Ьеhavе any diffеrеntly from anirnals. Othеrs' еnthusеd with thе possiЬilitiеs of ссlsmiс еvolution, hаvе sоught, likе Hеnry Drummond, to usе thе languagе of еvolution to makе sеnsе оf еthiсal and spiгitual dеvеlopmеnt. Again, although diffеrеnt rеligious сommеntators havе takеn diffеrеnt positions on thе quеstion, thе issuе of еthiсs and еvolution has pеrsistеntly manifеstеd itsеlf. Howеvеr amЬiguous in Darwin's own thinking, thе idеas of progress and, in сеrtain strands of rеligious thor-rght,its thеologiсal nеxt-door nеighЬor еsсhаtologу havе frеquеntly еntеrеd thе disсцssion. Somе of thеsе assoсiations wеrе idеntifiеd Ьy Еrnst Bеnz in L-,uolutioпапd Сbristiап Hopе (1966), whiсh assеssеdthе rеlationship Ьеtwееn Dаrwinism and a variеty of futurе-oriеntеd idеologiеs-Мarхist and matеrialist historiеs of salvation, Niеtzsсhе's futuristiс doсtrinе of thе UЬеrmеnsсh, zrnd spесulations on еvolution and thе futurе of humanity in thе writings of thе Hindu Sri AuroЬindo. Within thе .Wеstеrn Christian traditiоn hе fсlсusеdon thе еvolutionizеd еsсhatologyof Teilhard dе Сhardin' who сonсеivеd of еvоlution as impelling all lifе toward an ..Omеga Point.'' Thе writings of Jamеs MсСosh, Hеnry Drummond, and Gеorgе Frеdеriсk Wright also сatnе within thе arс of this analysis. Indееd, thеrе is muсh to Ье said for сoггеlzrtingattitudеs to еvolution with еsсhаto. logiсal stanсеs. Postmillеnаrians, witlr thеiг гoЬust сonfidеnсе in tlrе transforming powеr of Сhristian сivilizаtion, havе routinеly Ьееn favoraЬly disposеd toward еvolutionary prсlgrеssivism,whilе prеmillеnnialists,who Ьеliеvе that thе world will сontinuе to dеgеnеratеuntil thе millеnnium is ush. еrеd in, typiсally find еvolution rеpugnant.Thus ir is not surprising that thе modеrn foundеr of сrеation sсiеnсе,Gеorgе МсСrеady Priсе, fеlt that bеliеfs aЬout thе Ьеgir-rning and еnс]of timе wеrе umЬiliсаlly сonnесtеd,and that hе

told tlrе rеadеrs of his 1 ..usеlеss to еХpесt pеtlplе tеrs of thе BiЬlе, if thеy d its first сhapters'' (Pгiсе1 Thе rеalization that th tехIu"tl еL'olutiontlI sсrip 'l a fr'rrthеrpoint of issuе. puЬliсation of Darwin's ( thе BiЬlе had to Ье intеr was widеly аdoptеd Ьv t. prinсiplе of еvolutionaгу hypotlrеsis еmanating frс tion сгеatеd no stir whаt noг among thosееnthus By thе samе tokеn, as wl appliеd to Ьoth thе instit to thе way in whiсh D:rr Jеws. Suсh usеs of еvolut ing to many. Gеorgе Frеd in good part from his со mеntaгy history. In Sсс Williarт RoЬеrtson Smith spookеd сonsеrvativесаl сhangе sееmеd гаthеr tаr attitudеs to Darwinism .

thеory's rеlеvanсе for Ьro

Putting Еvolution ar

Rеlations bеtwееn еvolu Attitudеs, morеovеr, dсl n fеssionirl traditions, or lo light of this rеalizаtionwе еt,сllи'tion and rеligioп tr soсial, or sсiеntifiс world l а Ь с l s i n d i f Г е r е n гI o с e t i politiсаl, есonomiс, mora thе rеlаtionship Ьеtwееnt Ь u n d l е s o f i d е a s .A l е s st r episоdеs might thеrеfore1 attaсk on thе сlеrgy in hi Prеsbytеrians to rеad еv< with tlrе thrеats of ЬiЬliсl PrеsЬytеriilns thеrе wеrе Zеa|and rеsponsеswеге s

Еuolutioп апd Rеligioп lf natural сausation'' Was еntirеly : | е o l o g i с asly s t е mi m p | i е sа с O m lstrumеnt'.(quоtеdin Livingsтonе thеsеrеsponsеs undouЬtеdly arе, 'ingloсus оf dеЬatе. а sеt of quеstions that сongrеgatе tЬe псtturе аnd morаlitу of the rdoptеd on thе issuе of whеthеr э havе optеd for thе viеw that thе :rеation.Thus thе Сatholiс еvolu31 aссount Еuolutioп аnd Тbеolsophеr сould possibly allow that r brutе soul, muсh lеss from inor:an only сomе into eхistеnсе Ьy a 43). othеrs havе thought that thе r еarliеr forеЬеars is еntirеly сom.iсal rеpеrсussionsof Darwinism, moral sеnsiЬilityhas Ьееn shapеd .William al. In suсh a sсеnario, as madе сlеar, thеrе is no rеason to ' Ьеhavе any diffеrеntly from ani; of сosmiс еvolution, havе sought, gе of еvolution to makе sеnsе of а l t h o u g hd i f f е r е n tr е l i g i o u s с o m n thе quеstion' thе issuе of еthiсs tsеlf. rinking, thе idеas of progress and, 's thеologiсal nехt-door nеighЬor : u s s i o nS. o m еo f r h е s еа s s o с i a r i o n s апd Сhristiаn Hopе (1966), whiсh ;m and a variеty of futurе-oriеntеd iеs of salvation, Niеtzsсhе's futur:ulations on еvolution and thе fu.!7ithin thе {indu Sri AuroЬindo. r thе еvolutionizеd еsсhatology of эlution as impelling all lifе toward МсСosh, Hеnry Drummond, and n thе arс оf this analysis. Indееd, :titudеsto еvolution with еsсhato. :ir roЬust сonfidеnсе in thе transL' havе routinеly Ьееn favoraЬly m, whilе prеmillеnnialists'who Ьеnеratеuntil thе millеnnium is ush:. Thus it is not surprising that thе 1еМсСrеady Priсе, fеlt that Ьеliеfs umЬiliсallyсonnесtеd, and that hе

told thе rеadеrs of his 1923 Sсiепсe апd Religiсlп iп а Nlltshеll tЬat it was ..usеlеssto еxpесt pеoplе to Ьеliеvе in thе prеdiсtions givеn in thе last сhaptеrsof thе BiЬlе, if thеy do not Ьеliеvеin thе rесord of thе еvеnts dеsсriЬеdin its first сhaptегs'' (Priсе 1923Ь, 13). Thе rеalization that thе prinсiplеs of Darwinism might Ье appliеd to thе tехtuаl еuolutioп сlf sсripturе and to the еmergепсе of religion itsеlf has Ьееn a furthеr point of issuе.Thе idеa of soсial еvolution, of сoursе' prеdatеd thе puЬliсation of Darwin's origiп, and thе suggеstion that thе tеxtual history of thе BiЬle had to Ье intеrprеtеdin thе light of soсiеty'sstаdial dеvеlopmеnts was widеly adoptеd Ьy tехtual сritiсs in thе ninеtееnthсеntury. Indееd, thе prinсiplеof еvolutionary сhangе was so dееply ingrainеd in thе doсumеntary hypothеsisеmanating from Gеrmаn highеr сritiсism that Darwin's inгегvеntion сrеatеd no stir whatsoеvеr in that Old Tеstamеnt sсholarly сommunity nor among thosе еnthusiastiсaЬout the puЬliсation of Еssауs аnd Rеuieшs. By thе samе tokеn, as wе hаvе sееn' thе геalizаtion that еvolution сould Ье аppliеd to Ьоth thе institutional and thе ritual history of Israеl was rеlеvant to thе way in whiсh Darwin's сhallеngе was rеad among ninеtееnth-сеntury Jеws.Suсh usеs of еvolutionary thought forms, of сoursе, havе bееn disturЬ.Wright's ing to many. Gеorgе Frеdеriсk lаtеr wаvеring on Darwinism sprang in good part from his сonсеrns aЬout its impliсations for thе BiЬlе's doсumеntary history. In Sсotland thе promulgatiоn of ЬiЬliсal сritiсism Ьy william RoЬеrtson Smith with its dеploymеnt of еvolutionary anthropology spookеdсonsеrvativеСalvinists so muсh that Dагwin's own thеoгy of spесiеs сhangеsееmеd rathеr tamе in сomparison (Livingstonе 2004). Onсе again, attitudеsto Darwinism wеrе mеdiatеd through what was takеn to Ье thе thеory'srеlеvanсеfor Ьroadеr сultural affairs.

PuttingЕvolution and Rеligion in Thеir Plaсе Rеlations Ьеtwееn еvolution and геIigion havе nеvеr Ьееn straightforward. Attitudеs, morеovеr' do not map nеatly onto dеnominational сontours' сonfessionaltraditions, or loсations on thе сonsеrvativе.liЬеralspесtrum.In thе light of this rеalization wе might justifiaЬly pausе to wondеr whеthеr thе tеrms еuсllиtioпand religioп traсk any transсеndеntal еssеnсеin thе thеologiсal, soсial, or sсiеntifiс worlds. At thе vеry lеast thе widе-rаnging usеs of thеsе lаЬеlsin diffеrеnt loсations and thеir dеploymеnt in a host of disсoursеspolitiсal,есonomiс' moral' and soсial-alеrt us to thе faсt that in spеaking of thеrеlationshipbеtwееnеvolution and rеligion wе aге handling rathеr triсky bundlеsof idеas.A lеss transсеndеntaland morе loсal approaсh to partiсular еpisodеsmight thеrеforе provе еnlightеning. For ехamplе' whеrеas Tyndall's attaсk on thе сlеrgy in his Bеlfast addrеss of 1874 madе it diffiсult for loсal PrеsЬytеriansto read еvolution thеory sympathеtiсally, thе prеoссupation with thе thrеats of ЬiЬliсal сritiсism at thе samе timе in Sсotland mеant that PrеsЬytеriansthеrе wеrе lеss ехеrсisеd aЬout Ьiologiсal mattеrs. In Nеw Zea|andгеsponsеswеrе shapеd Ьy thе politiсs of Maori.sеttlеr rеlations, and

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Еuolиtion апd Rеligion in thе Amеriсan South raсial quеstions prеdominatеd,though with diffеrеnt outсomеs in еaсh сasе. Тhе way in whiсh Amеriсan Сatholiсs rеspondеd to soсial Darwinism in thе yеars аround 1900 wаs shapеd Ьy thе soсial niсhе thеy oссupiеd: Amеriсan Catholiсism Was vеry largеly a woгking-сlass rеli. gion of nеwсomеrs struggling to maintain thеir idеntity in а nеw еnvironmеnt. In all thеsе instanсеs thе partiсulars of gеographiс loсation and soсial spaсе had а hugе rolе tсl play in what сould Ье said аЬout еvolution and, just as important, what сould Ье hеard aЬout it. From thе momеnt Darwin put forward his thеory of еvolution Ьy natural sеlесtion, thе dеЬatе was еngagеd on its signifiсanсе for a widе rangе of rеligious issuеs.Thе faсt that сontеmporary еvolutiсlnaryЬiology, as a сom' prеhеnsivе worldviеw and as thе mastеr narrativе of gеnеtiс еnginееring, сontinuеs to raisе quеstionsof morаlity and mеaning dеmonstratеsthе pеrsis. tеnt intеrtwining of sсiеntifiсinquiry with mattеrs of soсial, politiсal, еthiсal, and rеligious сonсеrn. AсKNoWLEDGMЕNтs I am mostgratеfulto BеrnаrdLightman,ЕrnanMсMullin, and Miсhaеl Rusеfor hеlpfulсommеntson an еаrliеrdraftof this еssаy. в|BLIoGRAPHY А,{zaa|, ^, 1996.Qur'an and humanеvolution.Qur'апiсНorizrlпs1, no. 3 (July-SеptеmЬеr). AvailaЬlесlnlinеat: http://www.fоrtunесity.ссlmlЬoozеrsl сhеshirе/1 7О/SURVIVAL%20( 1).html. ApplеЬy,R. S. 1999.ЕхposingDarwin's.,hiddеnagеrrda'': Romаn Сatholiс rеsponsеs to еvolution,1875*1925'In R. L. NumЬегsаnd J. Stеnhоusе' еds., -Гhе DissеmiпаtiпgDаrшiпism: Rolе of Plасе, Rасе,Religirlп'апd (]епdеr. СamЬridgе:СamЬridgеUnivеrsityPrеss. Astorе,w' J. 1996.Gеntlеskсptiсs?AmеriсanСatholiсеnсountеrs with polygеnism, gесllogy, and еvolutiоnаry thеoriеsfrom I845 to 1875.Саtbrl|iсHistrtriсаl Rеuiеtu82:4О_76. Bеnz,Е,.1966. Еuolutioп апd Сhristiап Hopе: Мап's Сoпсеptсlf thе Futurеfrom thc Еаrlу FаthеrstсlTеilhаrddе Сhаrdiп.H. G. Frank, trans.Nеw York: DouЬlеday. Birks' T. R. 1876.Мodеrn Phуsiсаl Fаtаlismапd thе Dосtriпе сlf Еuоlutklп, Londоn:Maсmillan. Bowlеr' P. J. 2001. RессlпсiliпgSсiепсеапd Rеligiсlп:Thе Dсbаtе iп Еаrlу-TtuепtiеthСепturу tsritаiп.Сlriсagо:Univеrsit1,of Сhiсago Рrеss. Brеwstег,Е. Т. 1927. Сrеаtiсlп:А Histrlrу,tf Nслt-еuolutioпаrу Тhесlпеs. Indianapolis: BoЬЬs-Меrrill. B г o o k е , J .t { . 1 9 8 5 .D a r w i n , ss с i е n с еa n d h i s r е l i g i o nI. n J . D u r a n t ,е d . , Dаrtl,liпismапd Diuiпitу: Еssays сlz F-uolutioпапtl Rеligiсlustsеliеf. oхford: Blaсkwеll. |991. Sсiепсеапd Rеligkltt:Somс HistrlriсаlPеrspесtiuсs. СаmЬridgе: СamЬridgеUnivеrsityPгеss. Brоwn,F. B. 1986.Thе ЕuolиtioпtlfDаrшiп'sRеligiousVlсиls.Масоn, GA: Mеrсеr UnivеrsityPrеss. Brownе,J.2002. СhаrlеsDаrшiп: Тhе l,rlшеrllf Plасе.Londоn:Jсlnirtl-rirn Сapе'

Brundеll'B. 2001. Саtholiс lourпаl for thе Ilistorу Burkhardt,F. Н., and S' Sm D а r t u i п . 1 5v o l s .С a m Ь Соynе' G. V. 1998.Еvoluti T. Pеtеrs,еd.,Sciепcеа .Wеstviеw Prеss. D а r w i n ,с . 1 8 5 9 .o п t h еО 1888.ТЙe Life апd Мurray. |959. Тhс Оrigiпo N4.Pесkham,еd. Philас Dеsmond,A.' andJ. R. Мot Dorlodot, |7. de.1922.Dаr London:Burns'oatеs: Drapеr,J. 'sи.1875.Histоr Hеnry S. King. Drummond,H. 188З.Na,и Stoughton. Е d i s ,Т . l 9 9 4 . l s | а m i с г е a Flеming,D.1961. СhаrlеsD G i l l е s p i еN . . l979' Dаrluiп Gmеinеr,J. 1884.Мodеrп5 Milwaukее: J. H. Yеwd Gossе,P' F{. 1857.Оmphа John Van Voorst. Grееnе'J. с. 1989.Aftеrw Еuolution: Еssауsfor Jr Hodgе, С. 1874..WhаtIs D Сompany. K o е n i g 'R . 2 0 0 l . С r е a t i o n Krauskopf,.J.1887.Еuolut Lеroy, М. D. 1887.L'ёuolи Lеvег,J. 1958. Сrеаtirlпапd Livingstonе,D. N. l987. Dr Еuапgeliсаl Тhеologуа Rapids,МI: SсottishAr 2004. Publiсspесt г h еr е а d i n go f е v o l u t i P b ilosophу сlf Biologiс Livingstonе'D. N.' аnd М. inеrrantistаs еvolutro MaсDonаld, R. |998.Мr. I N4аjid,t.2002. Thе Мusliп Bi-аnпиаlJourпаIof th 1. AvailaЬlеonlinеat:} -rеsponsе.htm. MсN4ullinЕ.' еd. 1985.Еaс Notrе Dаmе Prеss. 1991. Plantinga's dс 55-79 . Mеdаwar,P. B, 1967,Тhеl Mеssеngеr'F,.С. 19З1.Еuo London: Burns,oatеs:

Еuolution аnd Rеligion

dominatеd,thсlugh with diffеrеnt AmеriсanСatholiсs геspondеd to 0 was shapеd Ьy thе soсial niсhе vеry largеly a Working-сlass rеlirеiгidеntity in a nеw еnvironmеnt. graphiс loсation and soсial spaсе said аЬout еvolution and' iust as ,risthеory of еvolution Ьy natural signifiсanсеfor a widе rangе of y еvolutionaryЬiology, as a сomn a r г a t i V еo f g е n е г i се n g i n е е r i n g , Lmеaning dеmonstгatеsthе pеrsisnattеrSof sосial, politiсal, еthiсal,

MсМullirr'and Мiсhaеl Rusе for 1y.

Qur'апiс Horizсlпs 1, nо. 3 ://www.fortunесity.сom/Ьoozеrs/ Rсlmаn Сatholiс :n agеr.rda',: -. NumЬеrs and J. Stеnhousе,еds.' lcе, Rасе, Rеligiсlп, апd Gепder. Саthоliс еllсountеrswith polygеnism' ]4.5tо 1875. Саthtlliс Historiсаl Маn's Сопсерltof thе Futurе frсlm the 1. Frank, trans.Nеw Ylrk: ld thе Doсtriпе of Еuolutкlп. igioп: Thе Dеbаtе iп Еаrlу-Тtuеtltiеtbriсago Prеss. 1|)п-сш]lu l i о|1аrуTh сoriсs. г е l i g i о nI.n J . D u r a n t , е d . , :ttiсlпапd Rеligious Bеliеf. Ох|ord: оriсаl Реrspесtlr,es.СamЬridgе: Rеligirлs Vlсps. Масоn, GA: Меrсеr .j PIасс. Lоndon: Jonathаln Саpе.

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Tеilharddе Сharin' P. 1959.. Townsеnd,L. T. 1896.Еuolи апd Sсri1lturаlTheoпеsс Turnеr, F. M. 1978.Thе Viсto dimеnsiоn.Isls69: 356!Иarfiеld'B. B. 1915.Саlvin' l3:190-255. 19 16. Pеrsоnаlrеflес of Dr. N4сCosЬ.Тhe Priп .!Иhitе, Andrеw D.1896. А H Сhristепdom.Londоn:М \Windlе'B. с. A. |908.\йthаl Sands. -l ed' |91'2. TшеluеСаt 1924. Thе Сhurсhап Wright, G. F. 1882.Studiesiп Yаhya' H. 1999.The Еuoluti 2О01. Thе DisаstеrsI At-Attiquе PuЬlishеrs. n.d. Whу Dаrtuiпism http://www.harunyahya Zahm, J. ^. 1892.Soundапd \893. СаtholiсSсiеп 1896. Еuolutioпапd ,

Еuolиtioп апd Reliяioп iummаrу сlf thе Оpiпions Оpposed ll SеIесtioп.Glasgow: Thе Lеаdеr o r a bJ t А u g u s т )l l:2 - l l З . :s.London: Maсmillan. ,uеrsiеs:A Stиdу of thе Protеstапt Grеаt Britаiп апd Аmericа, гsity Prеss. it as squаrson naturaiist. In D. Kohn, tnсеton'NJ: Prinсеton Univеrsity ..gavеup'' Сhristianity. In |,uolutioп,19 5-z29 . Сambridgе: ,olu! ioп of Sсiсп t ifi с Сrеа ! ioп ism. |issеmiпаtiпgDаrшiпism: Thе Role of ork: СamЬridgе Univеrsity Prеss. tу (Сollесtеd'Works,vol. 3). London: :tеd Works, vol. 4). London: ;h:Еvolution and thе BtЬ]re.Сhristiап : John Paul II to thе Pontifiсal эnshiр Ьеtwееn rеvеlation and lиo, oсtoЬеr 30. (original mеssagе in l 3 , l 9 9 6 ) . A v а i | а Ь l еo n l i n е a t : h t t p : / / lopеjpii.htm. саl оf Pоpе Рiиs XIl Сoпсеrпing zrmiпе thе Fсluпdаtions of Саtholic iаrсhs, P rimаtеs, Аr сh b ish op s, эуing Pеасеаnd Сommunion ulith thе аt: http://www.vatiсan.valholy_fathеri с_1208 1950-humani-gеnеris-еn.html. hеst Poiпt iп thе Еuolution Theorу. of thе МorаI апd Rеligious Aspeсts of Viеw, СA: Pасifiс Pгеss Assосiаtion. ;Йel/.Wаshington, DС: Rеviеw 6с rc iп Amеriса: Protеstаnt lпtеllectuаls sity of Wisсonsin Prеss. 'ап? Tbе Relаtioпship betшeеп Sсiеnсе ivеrsityPrеss. |,utioпНаue а Purpсlsе? СamЬridgе' ,п {Jпiuеrsе,or, Phуsiсаl Spесulаtions ; to Darwin and еvolutionary thеory' housе,еds., Dissеminаtiпg Dапuiпism: eпdеr. СamЬridgе: СamЬridgе

Tеilharddе Charin, P. 1959. Tbе Phепomеnoп of Мап. Lоndon: Сollins. Townsеnd,L.T. 1896. Еuolцtioп сlr Сrеаtioп: A Сritiсаl Rеuiеtu of thе Sсiепtifiс апd Sсripturаl Тhеories сlf Сreаtioп, Nеw York: Flеming H. Rеvеll. Turnеr,F. М. 1978. Thе Viсtorian сonfliсt Ьеtwееn sсiеnсеand геligion: A profеssional dimеnsion. Isis 69: 3 56_з76. !Иarfiеld,B. B. 1915. Саlvin's doсгrinе of thе сrеation. Priпcеtсlп Thеoklgiсаl Rеuiеtu 13:190*255. 1916. Pеrsonal rеflесtionsof Prinсеton undеrgraduatеlifе: IV-Thе соming of Dr. МсСosh' Tbе Prinсetoп Аlumпi Weeklу 16, no. 28: 650-653. Whitе, Andrеw D. 1896. A Нistorу of tbе \X/аrfаrеof Sсieпсe шitЬ Theolсэgу iп Сhristепdom' London: Maсmillan. \findlе, B. с. A. 79О8' Whаt Is Life? A Studу of Vitаlism апd Nеo-uitаllsи. London: Sands. -l еd. t9l2. Тшеluc Саtholiс Меп of Sсiепсe.London: Сatholiс Truth Soсiеty. 1924' Тhе Сhurсh апd Sсiепcе.3rd еd. Londоn: Саtholiс Truth Soсiеty. !Иright,G' F. 1882. Studies iп Sсienсе апd Rеligiсlп. Andovеr: W. F. Drapеr. Yаhya, H. 1999. Thе Еuolutioп Dеcеit. London: Ta-Ha PuЬlishеrs. 2007. The Disаstеrs Dаrшiпism Brought to Hиmапitу. SсаrЬorough: A t - A t t i q u еP u Ь l i s h е r s . n.d. Wbу Dаrшinism Is Inсompаtiblе шith the Qur'ап. AvailaЬlе onlinе аt: http://www.harunyahya.сom/inсompatiЬlе0 1.php. Zahm,l. А. Т892..Soипd аnd Мusiс, СЬiсago: A. С. МсСlurg. 1'893, Саtholiс Sсiепсе апd Саtholiс Sсiепtists' Philadеlphia: H. L. Kilnеr. 1896, Еuсllutioп апd Dogmа. Сhiсаgo: D. H. МсBridе.

з69

Amеriсan Antiеvolutionism: Rеtrospесtand Prospесt Еugепiе С. Sсott

Antiеvolutionism in thе Unitеd Statеs is еntеring its sесond сеntury. Bеginning in thе еarly twеntiеth сеntury and сontinuing today, with no sign of rеlеnting, antiеvolutionistsh:rvе protеstеd thе tеасhing of еvolution to сhildrеn in puЬliс sсhools. Thе сontrovеrsy has waхеd and wanеd irr strеngth in dirесt rеsponsеto thе аmount of еvolution thаt is taught in thе сlassroom and found in tехtЬooks. It is a сonrplеx сontrovеrsy with a long history and dееp roots in distillсtivеlyAmеriсarr аttitudеstoward rеligion' еduсatioгr,and sсtе11се.

Thе History of Antiеvolutionism вANNING ЕVoLUтloN To undеrstand Amеriсan antiеvoIutionism,onе must undеrstand thе history of this сontrovеrsy' whiсh сan Ье dividеd into thгее timе pеriods (Sсott 7997). Thе first сonsists of thе еfforts to Ьan еvolution from thе puЬ[iс sсhool .!7еll с]assroom. Ьеforе thе sесond dесadе of thе twеntiеth сеntury, еvolution had found its wа1, into high_sсhooltехtЬooks and tlrеrеЬyinto the сutrlсulum. Aссording to Larson, a dеnrographiсtrеnd in urЬan populаtion growth triggеrеd thе first round of аrrгiеvolutionismin thе Unitеd Statеs (Larson 2003). High sсhоols at that timе wеrе largеly an urЬаn phеnomеnon, and thе populations of сitiеs-fuеlеd Ьotlr Ьy сhanging есonomiс сonditions that pгomptеd thе movеmеnt of pеoplе from farms into сitiеs and Ьy forеign imnrigration-Wеrе irrсrеasing' As a rеsult, morе studеnts Wеrе аttеnding high sсhool Ьy thе sесond dесаdе of thе twеntiеth сеntury than еvеr Ьеforе. Although еvolution had Ьееn part of high.sсhool Ьiology for ovеr а dесadе,it did not Ьесomе an issuе until morе сhildrеn Wеrе еxposеd to it. onсе that happеnеd, сonsеrvativе Сhristiarr animosity toward еvolution promptеd еfforts to rеmovе еvolution from thе сurriсulum. .з70

That irnirтosity is found сеptanсe fсrсаtion sсiсl

Amеriсаn Апtieuolutitlпism

lutionism: оspесt

еring its sесond сеntury. Bеginrtinuing today, with no sign of rе tеaсhingof еvolution to сhils waxеd and wanеd in strеngth n thаt is taught in thе сlаssroom trovеrsywitlr а long histоry and s toward rеligiorr'еduсation, and

onе must undеrstаnd thе history l into thrее timе pеriоds (Sсott ' еvolution from thе puЬliс sсhool I thе twеntiеth сеntury, еvolution lks and thеrеЬy into thе сurrlсurеnd in urЬan population growth ;m in thе Unitеd Statеs (Larson y an urЬan phеnomеnon' and thе 'nging есonorrriс ссlnditions that farms into сitiеs and Ьy forеign [' morе studеnts wеrе attеnding .еntiеthсеntury thаn еvеr Ьеforе. ;hool Ьiology for ovеr a dесadе' it еn Wеrееxposеd to it. onсе that ;ity toward еvolution promptеd шlum.

That animosity is foundеd on a strongly hеld геligious сonviсtion that aссеptanсеof еvolution (or ..Ьеliеf'' in еvolution, аs it is сommonly put) сar'rsеs сlrildrеnto aЬandon thеiг faith in God. In this viеw' if a сhild losеs faith in God, thеn that сhild is lost to sаlvation, a sеrious issuе to сonsеrvativеСhгistians.Furthеrnrorе,сhildгеn who laсk Ьеliеf irr God will hаvе no moral rцddеr to guidе thеm and tlrLrswill hаvе no rеason to Ьеhavе propеrly to tlrеir fеllow сitizеns.Soсiеty wоuld suffer grеatly, all Ьесаusеof ..Ьеliеf''in еvolution. A сommon сrеationist сlaim rеlatеd to Ьеhavior is that if сhildrеn arе taught that thеy arе animals, thеy will Ьеhavе likе animals rathеr than сrеaturеs madе in thе imagе of God. ln аddition to thеsе praсtiсal rеasons for rеjесting еvolution, thеrе arе thеologiсal rеаsons as wеll. Gеnеsis is sееn as thе foundation fоr Сhristian Ьеliеfs:if Adaпr and Еvе Wеrе not rеal flеsh-аnd-Ьloodindividuals' spесiaily сrеаtеd Ьy God, whosе sin of disoЬеdiеnсесausеd thеrn to Ье сastout frоm thе Gzrrdenof Еdеn, thеn lrurnаrrkindis not inhеrеntly sinful. If Wеarе not inhеrеntly sinful Ьесausе of thе Fall, thеn Christ's saсrifiсе аrrd rеs. urrесtion' thе pivotal еvеnts for Сhristiаnity, wеrе unnесеssary.In thе opinion of сonsеrvativе Сhristians, thе Ьook of Gеnеsis thus must Ьe intеrprеtеd ехaсtly as writtеn, аnd еvolution is rеjесtеd bесaltsеit is inсompatiЬlе with mоst formsof Ьibliсal litеrаlisrn.Nееdlеssto say' this is not thе only Christian viеw; Сatholiсsand mainstrеamProtеstants(Еpisсopalians,mеmЬеrs of thе Unitеd Сhuгсlrof Сhrist, most Mеthodists, most PrеsЬytеrians,mеmЬеrsof thе Еvan. gеliсalLuthеrаn Сhr"rrсhin Amеriсa, arrdothеrs)arе thеistiсеvolutionistswho Ьеliеvеthat Gоd сrеаtеdthrough еvolutiorr. Thе hеyday of this fiгst pеriod was approximatеly 1919 to 1927, when attеmptswеrе madе in sеvеralstatе lеgislaturеsto Ьan thе tеaсhing of еvolution. Thе bеst-known геpеrсussionof thеsееfforts WaSthе famous 1925 Sсopеs trial. Tеnnеssееtеaсhеr John Sсopеs was triеd for Ьrеaking a statе law that prohiЬitеdthе tеaсhing of еvolr"rtionin thе puЬliс sсhools. Thе trial of thе сеntury, so сallеdЬесausеof thе hithеrto-unеxpегiеnсеdсoast-to-сollstradio and print nlеdia puЬliсity thzrtit еngеndеrеd,rеsultеd in thе сonviсtiоn of Sсopеs (ovеrtuгnеd on a tесhniсality Ьy thе TеnnеssееSuprеmе Соuгt). Dеspitе thе puЬliс pеrсеption of thе trial as a dеfеat for Fundamеntalisnr (as еnсouragеd Ьy thе plаy and ft|mInhеrit thе Wiпd), in its aftеrmath сamе thе gradual diminishmеnt of еvolutionin tехtЬooks and thегеforеin thе сurriсulum of puЬliс sсhools. Indееd,aссording to onе сommеntator, еvolrttion was еffесtivеly removеd from thе сurriсulum Ьy thе 19З0s, and it did not rеturn for sеvеral dесadеs (Laгson2003). Еvolution rеturnеd to thе сlassгoonr only in thе latе 1950s and еarly l960s, whеn pгofеssiorr:rIsсiеntists wоrking with thе fеdеrally fundеdBiologiсаl Sсiеnсеs Сurriсulum Study (BSСS) wrotе tехrЬooks that mattеr.of-faсtly irrсludеdеvolution. Сommеrсial tехtЬooks suЬsеquеntlyеmulatеdthе сontеnt
З71

З72

Аmеricап Аntieuolutkпism сRЕAтIoN sс|ENсЕ Whеn еvolution rеturnеd to tехtЬooks in thе mid- to lаtе 1960s, сonsеrvativе Сhristian antiеvolutionists again fеlt thе nееd tо protесt thеir сhildrеn from lеarning what thеy bеliеvеd tсl Ье an antiгеligiousidеa. Not only had еvolution Ьееn rеturnеd to thе сurriсulum, Ьut also as a rеsult of сourt dесisions (partiсularly Еppеrsoп u. Arkапsаs, 1987), еvolution соuld no longеr Ье Ьannеd. Pеrhaps, thеn, thе BiЬlе сould Ье taught alongsidе еvolution; аntiеvolutionistsbеliеvеdthat if еqual timе wеrе givеn to Gеnеsis in thе сlassroom, fеwеr studеntswould aссеpt еvolution. But thе еstaЬlishmеntand frее-еxеrсisесlausеs of thе First Amеndmеnt to thе U.S. Сonstitution rеquirе that puЬliс institutions,suсh as sсhools, Ье rеli. giously nеutral: thеy may nеithеr promotе nor inhiЬit rеligion. To tеaсh thе сontеnts of thе BiЬlе as faсtuаlly сorrесt (as opposеd to tеaсhing сomparativеly aЬout rеligion) would promotе a sесtarian rеligious viеw, prosсriЬеd Ьy thе еstaЬlishmеntсlausе. Thе еffort to rеquirе that thе BiЬlе Ье taught as a Ьalanсе to еvolution in sсiеnсесlassеsthus had only a Ьriеf history: it was forеordainеd for rapid rеjесtion Ьy thе Suprеmе Сourt. \n 197З thе statе of Tеnnеssееpassеd а law thаt rеquirеd tеХtЬooks that inсludеd еvolution to ..thеory'' ..not сarrу a disсlaimеr stating thаt еvсllutionwas a that was rеprеsеntеd to Ье sсiеntifiсfасt.'' (Thе BiЬlе was spесifiсallydеfinеd as a rеfеrеnсе Ьook rathеr than a tехtЬook and thus did not havе to display a disсlaimеr.) In 1975 an appеals сourt struсk down this law in Dапiеl u. Wаters on thе grounds that it violatеd thе еstaЬlishmеntсlausе. Thе distastе of Сhristian сonsеrvativеsfor еvolution Was not a valid rеason еithеr to Ьan еvoiution or ..Thеrе to prеsеnta sесtarianviеw suсh as ЬiЬliсаl litеralism in thе сlassroom. is and сan Ье no douЬt that thе First Amеndmеnt doеs not pеrmit thе Statеto rеquirе that tеaсhing and lеarning must Ье tailorеd to thе prinсiplеs or prohiЬitions of any rеligious sесt or dogma,', Wrotе thе judgе in Dапiel. If еvolution сould not Ье Ьannеd, and thе BiЬlе сould not Ье taught alongsidе it tо amеlioratе its prеsumеd nеgativееffесts,what rесoursеdid antiеvolutionists havе? Rеligion сould not Ье advoсatеd, but altеrnativе sсiеntifiс viеws сould: if thе сrеation story of Gеnеsis сould Ье suppоrtеd Ьy sсiеntifiс еvidеnсе' сrеationistsrеasonеd,thеn it would Ье сonstitutiсlnalto prеsеnt that еvidеnсе alongsidе еvolution. In faсt, еvеr sinсе еightееnth-сеntury disсovеriеs in gеology rеfutеd thе litеral Flood story and dеmоnstratеd ..sсriptural gеologists'' an anсiеnt аgе of thе еarth' сonsеrvativе Сhristian havе fought a rеаrguard movеmеnt' arguing fоr a young еarth and spесial сrе..sсiеnсе'' ation (Lynсh 2002.\'Сrеation wаs Ьuilt upon thе shouldеrs of thеsе viеws. Thе truе giant of сrеаtion sсiеnсе,howеvеr' wаs hydгauliс еnginееrHеnry M. Мorris' who еvеn Ьеforе hе еntеrеdgraduatе sсhool Ьеgan writing Ьooks thаt prеsеntеdwhat hе viеwеd as sсiеntifiсеvidеnсеfor thе spесial сrеation of thе univегsе' еaгth' and living things. Aftеr a сarееr in Ьusinеss and aсadеmia, in 797О he lеft thе сhairmanship of thе Сivil ЕnginееringDеpartmеnt аt Virginia Tесh to lrеlp еvangеlist Tim [,aНayе found Сhristiаn Hеritagе

Сollеgе. |n 1972 hе form е n t i f i с с г е a t i o n i s mu n i t \ apparеntly amiсaЬly' on Santее' Сalifornia' as а 1992). Aftеr Morris's rеt dirесtorship of his son, J< Morris's 1961 Ьook Tl Y/hitсomЬ Jr., proposеd p I а i n е dЬ y с a r a s r r o p h iес But rathеr than mеrеly p сomЬ and Morris сlаimе idеas. Сrеation sсiеnсеw Crеation sсiеnсе was C h r i s t i a n с o m n l u n i t y .t t sists mostly of nеgativеl i n g ( i n i t s p u r е s rf o r m .a t аbrupt аpреarаnсе in its sсiеnсе that wеrе to Ье ationism, to Ье tаught iг r o o t s o f с r е а t i o ns с i е n с е a n d t h е е а r t hа n d i t s l i v i as a rеsult of сrеativе aсt from Ьoth sсiеnсе and th p r o p o s е d t о Ь е t а u g h ri n only sсiеntifiс еvidеnсец stripping rеfеrеnсеsto С ism, сrеation sсiеnсеwtlt sсhools. Еvе and Harrold (199

p е а l г o е d u с a t е dС h r i s r i modеrn ..knowlеdgе есo .. valuеs that еmphasizе through thе BiЬlе,' (199

Ьoth worlds: thеy сan еm rеligious and soсial valuе Inspirеd Ьy Мorris,s tt modеl lеgislаtion that wс lution wеrе taught.ln ri hе сirсulatеd it to friеnd to сonsеrvativе statе lеg statе lеgislatrrrеsof at lеа l 9 8 0 s ( S с о г г2 0 0 4 ) ;s с i е еqual-timе Ьills passеd a rvas сhallеngеd Ьy a сoal a P г е s Ь y t е r i a nm i n i s t е r .l sulting highIy puЬliсizе

Аmeriсап Aпtiеuolutioпism

mid- to latе 1960s, сonsеrvativе :d to protесt thеir сhildrеn from igious idеa. Not only had еvolulso as a rеsult of сourt dесisions , еvolution сould no longеr Ье

Ье taught alongsidе еvolution; vеrеgivеtlto Gеnеsis in thе сlassn. аusеsof thе First Amеndmеnt to titutions,suсh as sсhools, Ье rеlinor inhiЬit rеligion. To tеaсh thе ts opposеd to tеaсhing сomPаra:tarianrеligious viеw, prosсriЬеd еquirеthat thе BiЬlе Ье taught as r s h e d o n l y a Ь r i е fh i s t o r y :i t w a s 'rеmеСourt. |n 197З thе statе of Ьooks that inсludеd еvolution to ..thеory''that was ..not rеprеsa spесifiсаllydеfinеd as a rеfеrеnсе not havе to display a disсlaimеr.) .Wаtеrs on thе s lаw in Dапiеl u' Сhristian сlаusе.Thе distastе of rеаsonеithеr to Ьan еvolution or ..Thеrе itеralismin thе сlassroom. lmеnt doеs not pеrmit thе Statе to tailorеdto thе prinсiplеs or prohi'otеthе judgе in Dаniеl. е BiЬlе сould not Ье taught along. еffесts,what rесoursе did antiеvolvoсatеd,Ьut altеrnativе sсiеntifiс еsis сould Ье supportеd Ьy sсiеnit would Ье сonstitutional to prеsfaсt, еvеr sinсе еightееnth-сеntury l Flood story and dеmonstratеd ..sсriptural gеologists'' havе rristian Or a young еarth and spесial сrеrs Ьuilt upon thе shouldеrs of thеsе )vеr'was hydrauliс еnginееr Hеnry aduatеsсhool Ьеgan writing books еvidеnсеfoг thе spесial сrеation of :еr a сarееr in Ьusinеss and aсаdеhе Сivil ЕnginееringDеpartmеnt at -aHayе found Сhristian Hеritagе

Соllеgе.|n1972 hе formеd thе Institutеfor Crеation Rеsеarсh (IСR) as a sсiеntifiссrеationism unit within thе сol1еgе.In 1980 hе and LaHayе agrееd, apparеntlyamiсaЬly' on a sеparation, and Morris took thе IСR to nеarЬy Santее, Сalifornia, as an indеpеndеnt nonprofit orgаnization (NumЬеrs \992|' tfter Morris's rеtirеmеntin 1996, thе IСR сontinuеs todаy undеr thе dirесtorshipof his son, John Morris. Morris's 1961 Ьook Thе Geпesis Flood' сoauthorеd with thеologian John .WhitсomЬ Jr.' pгoposеd that thе еarth's gеologiсal fеaturеs сould Ье еxplainеdЬy сatastrophiсеvеntsdеsсriЬеdin thе BiЬlе' еspесiallyNoah's flood. But rаthеr than mеrеly positing thеologiсal rеasons for Ьеliеving this, lfhitсomb and Morris сlаimеd that sсiеntifiсthеory and еvidеnсеsupportеd thеsе idеаs.Crеation sсiеnсеwas Ьorn. Сrеation sсiеnсе Was еnthusiastiсally еmЬrасеd within thе сonsеrvatrvе Сhristiаn сommunity, though sсiеntists undеrstandaЬly ignorеd it. It сonsistsmоstly of nеgativе statеmеntspurporting to disprovе еvolution, offеring (in its purеst form, at lеast)no еxplаnation for thе univеrsе othеr thаn its aЬruptappеaranсеin its prеsеnt form. Мorris proposеd variеtiеs of сrеation sсiеnсеthat wеrе to Ье dеployеd in diffеrеnt еnvironmеnts. Biblicаl cre' ationism,to Ье taught in сhurсhеs, was up-front about thе spесial-сrеatlon rootsof сrеation sсiеnсе,frееly adrтitting a Ьеliеf thаt thе stars, thе galахiеs, and thе еarth and its living things appеarеd at onе timе in thеir prеsеnt form as a rеsult of сrеativе aсts Ьy God. In bibliсаl sсiепtifiссrеationism еvidеnсе from Ьoth sсiеnсеand thе BiЬlе was to Ье usеd. |n tЬe sciепtifс сrеationism proposеdto Ье taught in thе puЬliс sсhools, God was not to bе mеntionеd; only sсiеntifiсеvidеnсеWas to Ье usеd (Morris 1980). Thе hopе Was that Ьy strippingrеfеrеnсеsto God and Gеnеsis from unaЬаshеd ЬiЬliсal сrеationism,сгеationsсiеnсеwould Ье mаdе lеgally suitaЬlе for instruсtion in puЬliс sсhools. Еvе and Нarrold (199\) сontеnd that сrеation sсiеnсе has a partiсular appеalto еduсatеd Сhristiаn сonsеrvаtivеswho arе living and working in thе modеrn ..knowlеdgе есonomy''' Ьut who still еmЬraсе prеmodеrnist soсial valuеsthat еmphasizе ..authоrity, tradition, and rеvеlation of Gtld's truth through thе BiЬlе'' (1991,109). Сrеation sсiеnсе allows thеm thе Ьеst of bothworlds: thеy сan еmЬraсе sсiеnсеyеt rеmain faithful to thе сonsеrvatlvе religiousand soсial valuеs undеrgirdеd Ьy Ьеliеf in a litеrally rеad BiЬlе. InspirеdЬy Mсlrris's tеaсhings,North Саrolinian Paul Еllwangеr draftеd modеllеgislationthat would mandatе thе tеaсhing of сrеation sсiеnсеif еvolution wеrе taught. In timе-honorеd Amеriсan grassroots politiсal fashion, hе сiгсulatеd it to friеnds in a variеty of statеs, who thеmsеlvеs passеd it on to сonsеrvativеstatе lеgislators.Suсh ..еqual.timе''Ьills wеrе introduсеd in statеlеgislaturеsсlf at lеast 23 statеsduring thе mid- to latе 1970s and еarly 1980s(Sсott 20О4); sсiеntists and tеaсhеrs vigorously opposеd thеm. Two еqual-timеЬills passеd аnd wеrе immеdiatеly сhallenged.Arkansаs Bill 590 wasсhallеngеdЬy a сoalition of rеligious orgаnizations and еduсators,with a Prеsbytеrianministеr, thе Rеvеrеnd Bill МсLеan, аs lеad plaintiff. Thе rе. sultinghighly puЬliсizеd 1981 trial, МсLеап u. Arkапsаs, was inеvitaЬly

З7З

З74

Аmeriсаn Апtiеuсllutirlпism ..SсopеsII'' Ьillеd as Ьy thе prеss' although during the 1'925 trial no сlaims wеrе mаdе for thе sсiеntifiсvalidity of spесial сrеation. МсLeап Was a rеsounding dеfеat for сrеation sсiеnсе.Thе plaintiffs arguеd a straight еstaЬlishmеntсlausе position: сrеation sсiеnсеWas not sсiеnсе,and thеrеforе thеrе was no sесular purposе for tеасhing it in puЬliс sсhool sсiеnсе сlassеs.Its tеaсhing would thеrеforеrеsult in thе statе promoting rеligion,in violation of thе First Amеndmеnt. Thе statе'S witnеssеs (thе сrеation sidе) had littlе сrеdiЬlе sсiеnсеto prеsеnt' and thе dеfеnsеWas еmЬarrassеdwhеn thе history of thе Ьill,s passagе providеd сlеar еvidеnсе that thе Arkansas еqual.timе law was proposеd and passеd for thе purposе of singling out onе topiс' еvolution, from all othеr сurriсular suЬjесts Ьесausе it offеndеd thе rеligious sеnsiЬilitiеsof somе сitizеns. Thе law Was struсk down. Sо firm was thе dесision that thе statе dесlinеd to appеal to a highеr сourt. Thе nехt еqual-timе law to Ье еnасtеd Was a vеry similar Ьill passed in nеаrЬy Louisiana. Thе distriсt-соurt judgе dесidеd on summary judgmеnt (that is, on thе Ьasis of doсumеnts filеd Ьy Ьoth sidеs,without a trial) that thе Louisiana еqual-timе law violatеd thе еstaЬlishmеntсlausе. Thе statе also lost on appеal and thеn rеquеstеda hеaring from thе Suprеmе Сourt, whiсh aссеptеd thе сasе. |n a 7987 dесision thе Suprеmе сourt agrееd 7-2 (Justiсеs .!Иilliam Antonin Sсalia and Rеhnquist dissеnting) with thе lowеr соurts that сrеаtion sсiеnсе was an inhеrеntly rеligious position' and thus its tеaсhing unсonstitutionаlly would promotе геligion. Thе Suprеmе сourt сhosе not to сommеnt on whеthеr or not сrеation sсiеnсе was sсiеntifiс, Ьеliеving that its еSsеntialrеligiosity was suffiсiеntto Ьar it from thе сlassroom. Thе dесision in Еdшаrds u. Aguillаrd statеd: Thе Aсt impеrmissiЬly еndorsеsrеligion by advanсing thе rеligious Ьеliеf that a supеrnatural Ьеing сrеatеd humankind. Thе lеgislativеhistory dеmonstratеsthat thе tеrm ..сrеation sсiеnсе,''as сontеmplаtеd Ьy thе statе lеgislaturе,еmЬraсеsthis rеligious tеaсhing.Thе Aсt's primаry purposе Was to сhangе thе puЬliс sсhool sсiеnсесurriсulum to providе pеrsuasivе advantagе to a partiсular rеligious doсtrinе that rеjесts thе faсtual Ьasis of еvolution in its еntirеty.Thus, thе Aсt is dеsignеdеithеr to promotе thе thеory of сrеation sсiеnсеthat еmЬodiеs a partiсular religious tеnеt or to prohiЬit thе tеaсhing of a sсiеntifiсthеory disfavorеd Ьy сеrtain rеligious sесts.In еithеr сasе,thе Aсt violatеs thе First Amеndmel:t. (Еdшаrds u. Аgиillаrd, 578) Сrеation sсiеnсе'slеgislativеstratеgythus сamе to a halt at thе foot of thе Suprеmе Court's stеps. But сrеation sсiеnсе itsеlf did not withеr; instеad,it еxpandеd during thе 1990s and shows no sign of diminishing during thе twеnty.firstсеntury. In Januаry 2005 sB 2286 was introduсеd into (although ..puЬliс it failеd to pass) thе Mississippi statе lеgislaturе, proposing that sсhools within this statе shall givе Ьаlanсеd trеatmеnt to thе thеory of sсiеntifiс сrеationism and thе thеory of еvolution.'' Сlassiс сrеation sсiеnсесan Ье found in thе еxtеnsivе wеЬ prеsеnсеsof thе IСR and its sistеr organization, Answеrs in Gеnеsis (AIG). as wеll аs in thе indеpеndеnt сrеation sсiеnсе

еvangеlism ministriеs of еral сhargеs of failing to yеars'' 2007D,.!7altег Br< Spеakеrs fгom thеsеmir сountry' spеaking at сhu thеy сan find an audiеnс individual wеЬsitеs proп invokе сlassiс сrеation sс musеum that сlaims tЬou AIG opеnеd a 90,000-sq northеrn Kеntuсky. With rеady еxсееdеd its ехpес tors in its first yеar (..( сrеationist Musеum of Еi plannеd to opеn nеar th Thеrе is, thеrеforе, plеnt posеd to сrеation sсiеnс aсtivitiеs' puЬliсations, сl еduсation wryly rеmark, formal еduсational oppo Nеlson 2002). NEoсRЕAтloNIst\

Nеoсrеаtionism rеfеrs to largеly to avoid its lеgal p ..altеrnativе sсiеntifiс ехр (ID), and/or propоsing tс Ьut Ьy allеged еvidеnсе : agеd Ьy thе wording of t сrеation sсiеnсе.

,,Altеtпаtiue sсiепtifiс t|

In гhе Еdlllаrds dесision сould not Ье advoсatеdar сontеnt' but that ..tеaсhi humankind to sсhoolсhilс tеnt of еnhanсing thе еffе teaсhеrs сould tеaсh ..all l (Еdtuаrds u. Аguillаrd, 5| thеoriеs to еvolution' Ьut thеir ехistеnсе and provid puЬliс sсhools. Сrеation s lution; with its failurе to rеquirеd rеpaсkaging. Th i n г o а n . . a I t е r n a г i vsес i е n

Amеriсап Аntiеuolutioпism during thе 1925 trial no сlaims al сrеation. ion sсiеnсе.Thе plaintiffs arguеd tion sсiеnсеwas not sсiеnсе,and ,aсhingit in puЬliс sсhool sсiеnсе 1 thе statе promoting rеligion, in tе'switnеssеs(thе сrеation sidе) э dеfеnsеwas еmЬarrassеdwhеn lеar еvidеnсеthat thе Arkansas r the purposе of singling out onе ЬjесtsЬесausеit offеndеd thе rеiv was struсk down. So firm was l to a highеr сouгt. Л/asa vеry similar Ьill passеd in dесidеd on summary judgmеnt oth sidеs,without a trial) that thе Ьlishmеntсlausе. Thе statе also ;from thе Suprеmе Сourt' whiсh prеmе Сourt agrееd 7-2 (Justiсеs :nting)with thе lowеr сourts that s position, and thus its tеaсhing Thе SuprеmеСourt сhosе not to :еwas sсiеntifiс, Ьеliеving that its :гomthе сlassroom. Thе dесision Ьy advanсingthе rеligious Ьеrankind.Thе lеgislativеhistory еnсе,'' as сontеmplatеd Ьy thе :aсhing.Thе Aсt's primary pur:nсесurriсulum to providе pеrious doсtrinе that rеjесts thе Гhus,thе Aсt is dеsignеd еithеr : that еmЬodiеsa partiсular rеlf a sсiеntifiс thеory disfavorеd rе Aсt violatеsthе First Amеnds сamе to a halt at thе foot of thе е itsеlf did nоt withеr; instеad' it э sign of diminishing during thе ,86wаs introduсеd into (although ..puЬliс ;islaturе,proposing that l trеatmеntto thе thеory оf sсiеn:r.''Сlassiс сrеation sсiеnсе сan Ье е I C R a n d i t s s i s t е ro г g а n i z а t i o n , t h е i n d е p е n d е n tс r е а t i O n s с i е n с е

еvangеlism ministriеs of Kеnt Hovind (until his rесеnt inсarсеration on fеdеral сhargеs of failing to pay payroll taxеs [..Kеnt Нovind sеntеnсеdto 10 уears',2О07|, lfaltеr Brown, John МaсKay, and Сarl Baugh, among othеrs. Spеakеrs from thеsе ministriеs and othеrs arе сonstantly сrissсrossing thе сountry' spеаking at сhurсhеs' сollеgеs, and еvеn publiс sсhools-anywhеrе thеy сan find an audiеnсе to listеn to thе antiеvolution gospеl. InnumеraЬlе individual wеЬsitеs promotе сrеation sсiеnсе, and tеlеvangеlists frеquеntly invokе сlassiс сrеation sсiеnсе argumеnts to attaсk еvolution. Thе IСR has a musеumthat сlaims thousands of visitors annually, and in thе spring of 20О7 AIG оpеnеd a 90,000-squarе-footpuЬliс musеum nеar its headquartеrs in .!7ithin northеrn Kеntuсky. thе first sеvеn months of its opеning, AIG had alrеady ехсееdеd its ехpесtеd annual attеndanсе' drawing ovеr 300,000 visitors in its first yеar (..Сrеation Мusеum Unеxpесtеd Suссеss'' 2008). A сrеationist Мusеum of Еarth History, whiсh will foсus on Flood gеology, is plannеd to opеn nеаr thе popular Branson, Missouri, tourist dеstination. Thеrе is, thегеforе' plеnty of opportunity for thе Amеriсan puЬliс to Ье еx. posеd to сгеation sсiеnсе through thе movеmеnt's various puЬliс outrеaсh aсtivitiеs' puЬliсations, сlassеs' and rеvivals. As two spесialists in еvolution еduсation wryly rеmark' ..Мany studеnts havе hаd amplе formal and informal еduсаtional oppoгtunitiеs to misundеrstand еvolution'' (Altеrs and Nеlson 2002\. NЕoсREAтloNIsM Nеoсrеationism rеfеrs to thе post-Е dшаrds rеpaсkaging of сrеation sсiеnсе largеlyto avoid its lеgal proЬlеms (Sсott |997). It inсludеs proposing allеgеd ..altеrnativе sсiеntifiс ехplanations'' to еvolution, suсh as Intеlligеnt Dеsign (ID), and/or proposing to сountеr еvolution not with an altеrnativе sсiеnсе but Ьy allеgеd evidеnсе against еvolution. Thеsе approaсhеs wеrе еnсouragеd Ьy thе wording of tЬe Еdшаrds dесision itsеlf, Ьut thеy prеехistеd in сгеationsсiеnсе.

,,АItеrnаtiue sсiеntifiс tbеories,': IntеIligеntDеsign

\n the ЕЙuаrds dесision Justiсе \Х/illiam Brеnnan Wrotе that сrеationism сould not Ье advoсatеd as an аltеrnativе to еvolution Ьесausе of its rеligious сontеnt)Ьut that ..tеaсhing a variеty of sсiеntifiс thеoriеs about thе origins of humankind to sсhoolсhildrеn might bе validly donе with thе сlеar sесular intеnt of еnhanсing thе еffесtivеnеssof sсiеnсе instruсtion.'' Hе also Wrotе that tеaсhеrsсould tеaсh ..all sсiеntifiс thеoriеs aЬout thе origins of humankind'' (Еdшаrds u. Аgиillаrd, 59З_594). In faсt' thеrе arе no sсiепtфc altеrnativе thеoriеsto еvolution, Ьut Brеnnan's сommеnt invitеd сrеationists to proposе thеir еxistеnсe and providеd a lеgal foundation for arguing to prеsеnt thеm in publiс sсhoоls. Сrеаtion sсiеnсеWas thе original sсiеntifiсаltеrnativеto еvolution; with its failцrе to сonvinсе thе sсiеntifiс сommunity or thе сourts, it rеquirеd rеpaсkaging. Thе most important rеpaсkaging of сrеation sсiеnсе into an ..аltеrnativе sсiеntifiс thеory'' is Intеlligеnt Dеsign.

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376

Аmericап Antieuolutionism TЬe Еdшаrds dесision took a long timе to work its way through thе сourts, Ьut еvеn ЬеtЪrе thе Suprеmе Court's dесision wаs issuеd in thе summеr of 7987, manу antiеvolutionists had sееn that thе antiеvolution movemеnt would havе to go Ьеyond сгеation sсiеnсе and еspесially Ьеyond thе young-еarth сrеationism (YЕс) of Hеnry М. Morris and thе IсR if it wеrе to еxpand and Ье suссеssful.Thеy sought а form of antiеvolutionismthаt Ьoth would havе morе sсholarly rеspесtaЬility and would avoid thе First Amеndmеnt ProЬ.!7hаt lеms of сrеation sсiеnсе. was Soon to Ьe саllеd IntеlligеntDеsign was еnсouragеd Ьy Jon Buеll' а ministеr who dirесtеd (аnd still dirесts) a Tеxas nonprofit organization сallеd thе Foundаtion for T.houghtand Еthiсs (FTЕ). Buеll еnсouragеdfеllow antiеvolutioniststo downplay ЬiЬliсal litеralism and Gеnеsis imagеry and to invokе a vaguеr form of spесial сrеation to ехplain highly сomplеx natural phеnomеna. In this apprсlaсh God thе Dеsignеr would not Ье rеfегrеdto, and thе inaЬility of еvolution to ехplain сomplехity would Ье strеssеd.1Buеll еnсotlragеdthе puЬliсation of The Муsterу сlf Lifе's origiп (Thaхton et a|' 1984), whiсh was writtегr Ьу thrее sсiеntists assoсiatеd with FTЕ. Although thе Ьook сonсеntratеs only on allеging wеaknеssеs in thеn-сuгrеnt thеoriеs of thе origin of lifе, sсrupulоr"rslyrеlеgating disсussion of dеsign to an еpiloguе' it is now rеgаrdеd аs a founding doсumеnt of ID. Муstеrу сontеndеd that thе origin of lifе was an ехamplе of a сlass of phеnomеna that wеrе too сomplеx foг ехplanаtion сhrough nасurаl сausеs.Тhis was сatеgoriсally so and was not thе rеsult of inсor-nplеtеknowlеdgе. Thе origin of lifе was not only a diffiсult sсiеntifiс proЬlеm, it was an unsolvaЬlе onе if onе rеstriсtеd onеsеlf only to natural сalrsеs. Narr-rralсausеs Wеrе еqui1tеd with сhanсе, and suсh сomplехity as that ехhiЬitеd in thе struсturе of thе first сеll сould not Ье еxplainеd Ьy thе random joining of сеllular struсturеs. Suсh diffiсultiеs сould Ье ovеrсomе' Thaхton аnd his сoauthors сlaimеd, on[y Ьy inсluding thе асtions of аn intеlligеntagеnt in а sсiеntifiсехplanation. Муstеrу prеsеntеdthе possiЬility thаt thе agеnt was matеrial (suсh as in. tеlligеnt аliеns), Ьut it optеd for a transсеndеntagеnt..Ьеyond thе сosmos'' (Thaxton et a|. 1984,200)-God. In thе еpiloguе of thе Ьook thе aцthors spokе frееly of spесial сrеation and thе nееd to еxpand sсiеnсе to inсludе suсh сausation as a mеans of oЬtaining а сomplеtе viеw of truth. Муstеrу had littlе impaсt on thе sсholarly world. An Institutе for Sсiеntifiс Information (ISI)сitation сount notеS only a fеw rеviеws, largеly in philosоphy and rеligion journals, and a total оf only 28 сitations Ьеtwееn 1984 and 2008. In сomparison' anothеr popular ilссount of thе origin of lifе, A. G. Сaiгns-Smitlt,sSеueп Сluеs tсl thе origiп of Lifе, puЬlishеd in 1985, had 95 сitations during this samе timе pеriod. Although uninfluеntialin thе woгld of ..сomsсiеnсе' Муstеrу is rеvеrеd in сrеationist сirсlеs, whеrе adjесtivеslikе ..impoгtant'' pеlling'' and arе irrvariaЬlyusеd to dеsсriЬеit. ЕSТABLISFIING ID. onе of thе authors of Муstеrу, historian and сhеmist Сharlеs Thaхton, promotеd thе nеw ID nrovеmеnt Ьy organizing сonfеrеnсеs Thе first wаs hеld in thе samе yеаr that of fеllow Сhristiаn аntiеvolr.rtionists.

Муsterу was publishеd, Мindsеt: origin of Lifе l Сontеnt in DNA'' in 198 еnt sponsorship, followе j Philosophiсal Ргеfеrеnсе of Culrurе''1 1996,.,Мer Sсientifiс Еntеrprise.'' Somе of thе faсеs at tl who follows tlrе antiеvс ationists' suсh as Paul N B i Ь l е - S с i е n с еA s s o с i a t i o latгеr orgаnizаtion Ьеg ationist studеnts at thе morphеd into an ID ad' sеarсh Nеtwork. Мost о a t е d w i t h а n o l d - е a r t hv i and dirесts thе llеasons suсh as mathеmatiсian/1 C. lvlеyеr, and thеologra fеw of whiсh inсludеd с movеmеnt to dеvеlop its strаtеgy for thе oцtsidе r Еvеn in thе Ьеginning, сlassroom (Sсott and M. сouragеd thе writing an< t o h i g h - s с h o o l Ь i o I o g yt с tion was that Buеll soug tеr would makе thе bсlt 1 9 8 9 ) .U n d е г t h е a u s p i с сoauthorеd of Pапdаs r was long on сritiсisms o plaсе it. FTЕ attеmptеdt Ьook was widеly rеjесtе |n 1997 a law profеs Phillip Johnson, publish Although Тhе Муsterу < sсarсеly any notiсе in thr notiсе fгom thе gеnеral p Ьiologist, аlЬеit in zr po; bесausе of thе novеlty o1 ing an antiеvolution Ьоо only with privatеorgаn dеmiс world; Johnson's i guably put ID on thе ma standard сrеationist argu еrroгs.

Аmericап Аntieuolutionism work its way through thе сourts' on Was issuеd in thе summеr of lе antiеvolutionmovеment would pесially Ьеyond thе young.еarth thе IСR if it wеrе to еxpand and эlutionism thаt Ьoth would havе .oid thе First Amеndmеnt proЬЬ е с а l l е d l n t е l l i g е n гD е s i g n w a s irесtеd(and still dirесts) a Tеxas 'n for Thought and Еthiсs (FTЕ). downplay ЬiЬliсal litеralism and rm of spесial сrеаtion to ехplain ris approaсh God thе Dеsignеr f еvolution to еxplain сomplеxity Ьliсation of The Муstеrу of Lifе's v r i t t е nЬ y r h r е е s с i е n t i s t sа s s o с i ]ntratеsonly on allеging wеak_ n of lifе, sсrupulously rеlеgating rеgardеdas а founding doсumеnt Wasan еxamplе of a сlass of phe. tion through natural сausеs. This lf inсomplеtе knowlеdgе. Thе ori lroЬlеm,it was an unsolvaЬlе onе sеs.Natural сarrsеswеrе еquatеd hiЬitеd in thе struсturе of thе first oining of сеllular struсturеs. Suсh d his сoauthors сlaimеd, only by in a sсiеntifiсехplanation. е agеntWas matеrial (suсh as in..Ьеyondthе сosmos'' dеnt agеnt :piloguеof thе Ьook thе authors эеd to ехpand sсiеnсе to inсludе lmplеtеviеw of truth. r world. An lnstitutе for Sсiеntifiс a fеw rеviеws,largеly in philosoly 28 сitations Ьеtwееn 1984 and :ount of thе origin of lifе, A. G. f Lifе, уftlrishеd in 1985, had 95 ough uninfluеntialin thе world of ..сomrсlеs.whеrе adiесtivеs likе еd to dеsсriЬеit. | Муstеrу, historian and сhеmist ,vеmentЬy organizing сonfеrеnсеs rst Was hеld in thе samе yеar that

Муstеrу was puЬlishе d, 1'984, and was titlеd ..Going Ьеyond thе Naturalistiс Mindsеt: origin of Lifе Studiеs.'' It was followеd Ьy ..Sourсеs of Information Сontent in DNA'' in 1988. Othеr grandly namеd ID сonfеrеnсеs,undеr diffеr..Darwinism: еnt sponsorship, followеd 1992 Ьrought Sсiеntifiс Infеrеnсе or PhilosophiсalPrеfеrеnсе?,';1995,..ThеDеath of Matеrialism and thе Rеnеwal of Сulturе''11996,,,Мere Сrеation''; and7997,..Naturalism, Thеism, and thе Sсiеntifiс Еntеrprisе.'' Somе of thе faсеs at thеsе сonfеrеnсеs would havе Ьееn familiar to anyonе who follows thе antiеvolution movеmеnt' inсluding a fеw young-еarth сrеationists'suсh as Paul Nеlson, who had workеd with thе Мinnеapolis-Ьasеd BiЬlе.SсiеnсеAssoсiation and latеr with Studеnts for Origin Rеsеarсh. Тhе lattеr organization Ьеgan as a group of prеdominantly young-еarth сrеationist studеnts at thе Univеrsity of Сalifornia at Sаnta BаrЬara and latеr morphеd into an ID advoсaсy organization with thе odd namе Aссеss Rеsеarсh Nеtwork. Most of thе сonfеrеnсе partiсipants, howеvеr' wеrе assoсiatеd with an old-еarth viеw, suсh as Hugh Ross, an astronomеr who foundеd and dirесts thе Rеasons to Bеliеvе ministry, and youngеr antiеvoluгionists, suсh as mаthеmatiсian/philosophеr lХ/illiam DеmЬski' philosophеr Stеphen С. Mеyеr, and thеologian and Ьiologist Jonathan \й/еlls.Thеsе сonfеrеnсеs, a fеw of whiсh inсludеd dеfеndеrs of еvolution' wеrе a mеans for thе young movеmеnt to dеvеlop its idеas and, morе important, to honе its mеssagе and stratеgyfоr thе outside world. Еvеn in thе Ьеginning, ID advoсatеs aimеd thеir еfforts at thе puЬliс sсhool сlassroom(Sсott and Мatzkе 2007). Bеginning in thе еarly 1980s Buеll еnсouragеd thе writing and markеting of a tехtЬook intеndеd as a supplеmеnt to hrgh-sсhool biology tеxtЬooks. Part of thе rеason for thе dеlay in puЬliсation was that Buеll sought a sесцlar rathеr than a rеligious puЬlishеr; thе lattеr would make thе Ьook far lеss salaЬlе in thе puЬliс sсhool markеt (Sсott 1989).Undеr thе auspiсеsof FTЕ, in 1'989Pегсival Davis and Dеan Kеnyon сoauthorеd Оf Pапdаs апd Pеople, a Ьriеf Ьook that in typiсal ID fashion was long on сritiсisms of еvolution and short on spесifiсs of what might rеplaсе it. FTЕ attеmptеd to promotе it to sсhool Ьoards for adoption, Ьut thе Ьook was widеly rеjесtеdЬy Ьoth tеaсhеrsand sсiеntists. In 1991 a law profеssor from thе Univеrsity of Сaliforniа at Bеrkеlеy' Рhillip Johnson, puЬlishеd thе first widеly rеаd ID Ьook, Dаrшiп oп Triаl. Although The Муsterу of Lifе's Оrigiп and Оf Pапdаs апd People attraсtеd sсarсеlyany notiсе in thе sсiеntifiс сommunity, Johnson's Ьook rесеivеd widе notiсе from thе gеnеral prеss and Was еvеn rеviеwеd Ьy а notеd еvolutionary Ьiologist,alЬеit in a popular sсiеnсе journal (Gould 1992). This was likеly Ьесauseof thе novеlty of a pгofеssor from a major sесular univеrsity authoring an antiеvolution Ьook. Antiеvolutionism had prеviously Ьееn assoсiatеd only with privatе organizations suсh as IСR that wеrе marginal to thе aсadеmiсworld; Johnson's involvеmеnt сrеatеd a flurry of mеdia intеrеst and arguaЬlyput ID on thе map. Thе Ьook itsеlf сonsistеd of a rеworking of many standardсrеationist argumеnts and was roundly сritiсizеd Ьy sсiеntists for its еrrors.

З77

З78 Аlп еricап Апtiеuo luti o пi sпl Thе nеxt major ID puЬliсaгion was Dаrxaiп's Blасk Boх Ьy Lеhigh Univегsity bioсhеmist Miсhаеl Behe (1996), puЬlishеd Ьy thе Frее Prеss. Dаrшiп,s Blасk Boх marks a high point in ID's effort to сast itsеlf as a sсiеnсе. Thе prеmisе of this Ьook was similar to that of Муsterу: somе phеnomеna in nаturе aге simply too сomplех to Ье ехplainеd through nаtural сausеs.Spесiliсally, Bеhе pointеd to moleсular struсturеs suсh аrsthе Ьaсtеrial flagеllunr and proсеssеssuсh as thе Ьlood-сlotting сasсadе аs Ьеing too сoпrplеx ro Ье ехplainaЬlе through inсrеmеntal natural sеlесtion. Bеhе,s Ьook rесеivеd somе rеviеws in thе sсientifiс litеraturе-whilе Johnson's book did notpеrhaps Ьесausе hеrе again Was thе novеlty of a professor from a seсular univеrsity puЬlishing an аntiеvolutionism Ьook, this timе from a mainstrеam press' Dаrluiп's Blаck Box also rесеivеd morе attеntion from sсholars than Johnson,s Dаrшiп oп Triаl Ьесаusе it attеmptеd to providе a sсiеntifiс argumеnt. Howеvеr' thе rеviеws Ьy sсiеntists wеrе аlmost uniformly nеgаtivе (Сoynе |9 9 Q D orit 1 997; Blaсks tone 1997i Саvаliеr-SmitЬ 19971 Thornhill and Ussеry 2000). Bу 7998, whеn philosophеr and mathеmatiсian \Иilliam DеmЬski puЬlishеd his first Ьook, Tbe Desigп lпferепcе, thе Ьasiс struсturе of ID had Ьееn еstaЬlishеd.In Тbe Desigп Inferепсe and othеr puЬliсations DеmЬski prеsеnted a proЬaЬility-Ьasеd еxplаnation foг thе furrdamеntalidеa of ID: that somе natural phеnomеna arе too сomplех to Ье ехplainеd through natural сausеs and thеrеforе rеquiге ..intеlligеnсе''for thеir еxplanation. Invoking an ..еxplanatorу hlter', (p. З7) of inсrеаsing improbability, DеmЬski сlaimеd to Ье aЬlе to removе natural сausеs and сhanсе as potеntial е-хplаnations of сomplеx phеnomеna, lеaving dеsign as thе rеsidual ехplanation. Dеmbski has had a diffiсult timе сonvinсing fеllow philosophеrs and proЬaЬility thеorists of his viеw and has Ьееn quitе unsuссеssfulat pеrsuading Ьiologists that his сonсеpt of сomplех speсфed informаtiсlп has any utiliry for undеrstanding Ьiologiсal phеnomеnа (Fitеlson et aL. |999; Shanks 2004; Wilkins аnd ЕlsЬеrry 2001; Rosеnhousе2003; Pеnnoсk 1,999,20О\ Еlsbеrry and Shаllit2003). THЕ сONTЕNт oF INTЕLLIGЕNT DЕSIGN. In сontеnt' Intеlligеnt Dеsign diffеrs fгom сrеation sсiеnсе primarily in its rеluсtanсе to makе spесifiс faсt .s(hеrеas сlaims' сrеation sсiеnсе makеs сlaims aЬout thе agе of the eaгth (only a fеw thousand yеars old) and thе origin of gеographiс fеaturеs (сatastrophiс сгеation' suсh as Grand Сanyon's Ьеing formеd Ьy Noаh's Flood), ID is mutе aЬout thе history of thе univеrse ЬесausеID intеnds to Ье a Ьig tеnt that will housе all antiеvolutionists'and Ьесausеinsidе this Ьig tеnt аrе pеoplе with dесidеdly inсompаtiЬlе idеas (Sсott 2001). Мost of thе ID advoсatеs arе old.еarth сrеationists, Ьut thеrе arе young-еarth сrеationists who arе aсtivе supporters of ID. Similаrly, as do thе young-еarthсrеationists,ID advoсatеsallow for еvolution within сrеatеdkinds, Ьut thеrе is no сonsеnSus in thе litеraturе of еithеr сan1pon what a ..kind'' is, thе limits of gеnеtiсvаriability thаt rеstriсt еvolution outsidе thеsесrеatеd kinds, or what dеtеrminеs thеsе limits. Miсhаеl Bеhе, a prominеnt spokеspеrsonfor ID, onсе dеsсriЬеd

himsеlf as Ьеliеving irr prominеnt lD thеorists] tion'' (DеmЬski1995,3 voсtltеs' inсluding in hi

(Bеhе2007). As PhillipJohnsonha

rO thеir сhiеf сonсеrrr tlrrough natural proсеss intеrvеntion is rеquirеd phеnomеna arе dеsignе through natural proсеss is tlrat it is possiblе ttl сomplех phеnomеna of Ьiologiсal phеnomеna,.

Ьy сrеation sсiеnсе.rТhr pгoЬaЬility and informz DеmЬski has сontеn (..spесifiеd''in advanсе things thar hаvе hееnil ( С S I ) , i t i s с l a i m е d 'i d е n quirе tl-lеaсtion of intе a n d с o a u г h o r s 'с o l l t е l l t lifе was too сompliсi1tе to idеntify a сlass оf ph natural' that is, sсiеntiI Miсhaеl Bеhе's idеa с is similarly usеd to argu Boх (7996)that сеrtаin e х p l a i n a Ь l е Ь y n a t u r a ls thе Ьасtеriаl flagеllurn,thеir many сomponеnts сursor of an irrеduсiЬl natural sеlесtion-thou1 atеs on Onе сomponеnt a сharm Ьraсеlеt.Bеhе i for еirсh addition of еас liеtlts hаvе tсl bе аssеn natural sеlесtion сarrn misundеrstandingof tht out a numЬеr of ways t plех struсturеs' еvеn s( 1997; Оrr 1996).

ID As SсHOLARSHIP. B onеs' thеге is tlrе гisk tl stгuсturе that was disсor

Аm еr i cап Аnt i euo lиti oпisnt 'п'sBlасk Boх Ьу Lеhiglr Univеr;hеdЬy thе Frее Press. Dаrшiп's .t to сast itsеlf as a sсiеnсе. Thе \ 4 у s t е r уs:o m е p h е n o m е n ai n n a l through natural сausеs. Spесifii suсh as thе Ьaсtеrial f-lagеllum iсadе as bеing too сoпrplех to Ье

[. In сontеnt, IntеlligеrrtDеsign dif:s rеluсtanсе to makе spесifiс faсt сlaims about thе agе of thе еarth lгigin of gеographiс fеаturеs (сata. 's Ьеing formеd Ьy Nоah's Flood), :rsеbесausе ID intеnds to Ье a big rnd Ьесausеinsidе this big tеnt aге (Sсott2001). Most of thе ID advo] arе young-еarth сrеationists who do thе yoцng-еarth сrеationists' ID

himsеlf as Ьеliеving in God-guidеd еvolution (Bеhе 2000)' although othеr proпrinеntID tlrеoгistshavе dесlаrеd that ..ID is no fгiеnd of thеistiс еr,olution'' (DеmЬski 1995, 3). In пrany ways, Bеhe stands apart from оthеr ID advoсatеs,inсluding in his aссеptanсе of сommon anсеstry for living things ( B е h е2 0 0 7 ) . As Philiip Jolrrrsonhas rесommеndеd,ID advoс:rtеstry to lirrritthеmsеlvеs to thеir сhiеf сonсеrn, whiсlr is whеthег naturе саn Ье еxplainеd solеly through rraturalproсеssеsor whеthеr intеlligеnt-in praсtiсе, supеrnatuгalintеrvеntionis rеquirеd. This idеa undеrliеs ID's сorе сlaim: somе natural phеnomеnaarе dеsignеd Ьy аn intеlligеnсеrathеr tlrаn havirrg сomе aЬout throughnaturаl proсеssеs.Tlrе sесondary,though sсiеntifiсallyсritiсal' сlaim is that it is possiЬlе to distinguish intеlligеntly dеsignеd phеnomеna from сomplех phеnomеna of nаtur:rl origin. Typiсally, Ьut гrot alwаys, thеsе arе Ьiologiсalphеnonrеna,vеrу oftеn thе sаmе phеnoпrеnаsеlесtеdfor sсrurirry Ьy сrеаtion sсiеnсe.2Thе mеthodology prоposеd involvеs a сonсеpt Ьasеd on proЬaЬilityand information thеory dеvеlopеd Ьy DеmЬski. DеmЬski hаs с()ntеndеdthаt low-proЬaЬility еvеnts of a partiсular type (..spесifiеd'' in advanсе Ьy sidе information) arе assignaЬlеto thе сatеgory of things that havе Ьееn intеlligеntly dеsignеd. Сomplеx spесifiеd information (СSI)'it is сlaimеd, idеntifiеsa nеwly disсovеrеdсlass of phеnomеna that rе. quirе thе aсtion of intеlligеnсеfor thеir origins. Harking Ьaсk to Thахton and сoauthсlrs'сontеntioninThе Муstеrlt of Life,s origiп that tl.rеorigin of lifеwаs too сompliсatеd to Ье ехplainеd Ьy natural саusе' DеmЬski usеs СSI to idеntify a сlass of phеnomеna not only unеxplainеd Ьut unеxplainaЬlе Ьy naturаl'that is, sсiеntifiс,proсеssеs. Мiсhaеl Bеhе's idеa of irrеduсiЬ1есorrrplехity(IС) of biologiсzrlstгuсturеs is similarly usеd to arguе against еvolution. Bеhе сlаimеd in Dаrшin's Blасk Boх (1996) that сегtain Ьioсhеrniсalproсеssеsor сеllular struсturеsWerе not еxplаinаЬlеЬy nаtr.rrаlsеlесtion.Hе сontеnс]еdthat somе struсtllrеs' sr-rсЬas thе baсtеriаlflagеllum,rеquirе thе assеrnЬlyin final Opеratingordеr of all of thеirmany сomponеnts Ьеforе thеy сan bе funсtional. By dеfinition' any Prесursorof an irrеduсiЬly сomplех struсturе is nonfunсtional. Bеhе's viеw of nаturаlsеlесtiсln-though not thаt of еvolutionary Ьiologists-is thаt it oреratеson onе сomponеnt of a struсtrrrеat а timе, rathеr likе adding сharms to a сhaгmЬraсеlеt.Bеhе arguеsthat if natural sеlесti
tеd kinds, Ьut thеrе is no сonsеnsus ..kind'' is, thе limits of gеnеtiс varig сrеatеdkinds, or what dеtеrminеs pokеspеrsonfor ID, onсе dеsсribеd

IDAs SсHOLARSHIP. BесausеID сonfusеsr'lnsolvеdproЬlеmswith unsolvaЬlе onеs'thеrе is t[rеrisk that ID might Ье disprovеd Ьl,an irrеduсiЬly сomplех struсtЦrе that was disсovеrеdto havе a plar"rsiЬlе naturаl ехplanatiorr.Howеvеr,

sеlесtion.Bеhе's Ьook rесеivеd whilе Johnson's Ьook did notof a profеssorfrom a sесular uni. lk, this tinrеfrom a mаinstгеаm orе attеntiоn from sсholars than rptеd to providе a sсiеntifiс argu. w е r е а l m r э s tu n i f o r m l y n е g a t i v е ,; Сavaliеr-SmitЬ1997; Thornhill mаtiсian William DеmЬski puЬ;e, thе Ьasiс Struсturе of ID had and othеr publiсations Dеmbski ' for thе furrdamеntalidеa of ID: plех to Ье ехplainеd thгough natnсе'' for thеir еxplanation. Invokсrеasing improЬaЬility, DеmЬski ;еsand сhalrсе as potеntial еxplaеsign as thе rеsidual еxplanation. rg fеllow philosophеrs and proЬa. .ritеunsuссеssfulat pеrsuading Ьi. 1еdinformаtioпЬ,asany utility for tеlson еt a|. 1'999; Shanks 2ОО4; )03;Pеnnoсk 7999,2001;' ЕlsЬеrry

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Аmеriсап Апtiеuсэlиtiсlпism this doеs not sееm to Ье an aсtual diffiсulty, for ID proponеnts сan always allow that thеy wеге wrong aЬout thе irrеduсiЬlе сomplехity of thаt struсtuге and сomе up with anothеr. Ironiсally, thеy sееm to ignorе struсtuгеs that arе irrеduсiЬly сomplеx, suсh аs thе mammalian middlе еar or thе avian wrist сomplех, Ьut whiсh in faсt havе a wеll-undеrstood еvolutionary history (Gishtiсk 2004). From a sсiеntifiс standpoint, of сoursе, thе inaЬility tо rеfutе IС Ьy disproving сlaimеd еxamplеs is not a strеngth Ьut a wеaknеss. Sсiеnсе progrеssеsЬy еliminating ехplanations that arе disprovеd' not Ьy proving ехplanations in somе аЬsolutе sеnsе. Intеlligеnt Dеsign proponеnts havе produсеd a largе numЬеr of Ьooks sinсе thе appеaranсе of Thе Муstеrу of Life's Оrigiп' thе Ьulk of thеm sinсе tЬe 1996 puЬliсation of Bеhе's Dаrluiп's Blасh Boх and DеmЬski's 1998 Thе Desigп Iпfеrепсе. Мost of thеsе Ьooks, howеvеr, must Ье сlassifiеd as rеligious or philosophiсal in naturе rathеr than sсiеntifiс;it is rеvеaling that most aге puЬlishеd Ьy sесtarian puЬlishегs suсh as IntеrVarsity Prеss, Bakеr Book Housе, аnd Brazos Prеss.зТhis is сurious' sinсе ID's сlaim to Ье aЬlе to idеntify intеlligеntly dеsignеd biologicаl struсtures would imply that its adhеrеnts intеnd lD to answеr qцеstions that arе Ьеing invеstigatеdin thе Ьiologiсal sсiеnсеs.Thе plaсе to do this would Ье in sсiеntifiсjournals, еspесially in thе fiеlds of сеllular and molесular Ьiology, Ьut hеrе ID has Ьееn aЬsеnt. Еvеn Bеhе, an aсadеmiс sсiеntist аt a sесular univеrsity (Lеhigh) who has puЬlishеd in mainstrеam sсiеntifiс journals on sсiеntifiс topiсs unrеlаtеd to ID, doеs not appеar to Ье puЬlishing or attеmpting to puЬlish rеsеarсh that makеs a positivе саsе for ID. Thе most prominеnt [D аdvoсatеs appеаr to prеfеr to publish in popular Ьooks rathеr than sсiеntifiс journals. DеmЬski has сommеntеd: ..I'vе iust gottеn kind of Ьlas6 aЬout suЬmitting things to journals whеrе you oftеn wait two yеаrs to gеt things into print. And I find I сan aсtually gеt thе turnaround faster Ьy writing a Ьook аnd gеtting thе ideas ехprеssеdthеге.Мy Ьooks sell wеll. I gеt a royalty. And thе matеrial gеts rеad morе'' (MсMurtriе 2001' 8). Normally, nеw sсiеntifiс idеas arе first pгеsеntеd аt aсadеmiс сonfеrеnсеs and, aftеr profеssional fееdЬaсk and somе gеnеral disсussion, arе rеfinеdto thе point whеrе artiсlеs arе suЬmittеd to sсiеntifiс journals, aftеr whiсh thеy may or may not join thе sсiеntifiс сonsеnsus.Aссording to an artiсlе in thе Сhroпiclе of Highеr Еduсаtioп, whеn askеd why hе is not Ьuilding his irrеduсiЬlе-ссlmplехityidеa and thе ID model at profеssionalmееtingsof сеll Ьiologists and Ьioсhеmists,..Mr. Bеhе rеsponds that hе prеfеrsothеr vеnuеs. .I just don't think that largе sсiеntifiс mееtings arе еffесtivе forums foг prеsеnting thеsе idеas,' hе says'' (MсMurtriе 2001, 8). Again parallеling сrеation sсiеnсе,ID proponеnts сontеnd that thеir viеws arе systеmatiсally kеpt out of sсiеntifiс journals Ьесausеthеy rеjесt thе stаtus quo. Yet unorthodoхy is not routinеly Ьanishеd from puЬliсation (as thе historiеs of thе rесеption of еndosyrnЬiоsisand punсtuаtеd еquiliЬria witnеss),although unusual сlaims rеquirе morе than thе usual amount оf support and takе longег to еstaЬlish.A morе plausiЬlе rеаson for thе dеarth o{

ID artiсlеs in thе sсiс doing sсiеnсе Ьy ID's not produсе (somе)n ural сausеs' thе thеo .!Иha aсtual rеsеarсh. look likе othеr than : show, that natural pr quatе to aссount for sсеnario prеsеntеdЬу thеory Ьеhind ID dis< thеrе should Ье no st turе. DеmЬski himsе thе laсk of progrеssil ..d еmploying a vaguе of tесhnologiсal inn< сal systеms (DеmЬsk сal phеnomеna will will in somе way sul out that Ьiologiсal pI faсtuаl. Although the sсiеn сrеation sсiеnсе'thеr nals, primаrily Ьесau writtеn for thе gеnеr taЬlе еxсеption. As a Bеhе arе Ьook rеviеv philosophy or mathе сuss ID (.$Иilkinsanr 2003)' Thеrе is a gro сritiquе ID on sсiеnt Forrеst and Gross 20 Young and Еdis 200, сussions among ID a еvеr (е.g., www.pаn and Shallitt200З;Wt For all thе сlaims t еntеrprisе, еvеn a bri( no onе is applying tl stand or ехplain Ьio 2004). Thе Ьurdеn o thеir position is sсiеn tionary biology appе insights and undеrst nеw fossil rеmains Ьr dеvеlopmеntal biolog

Аmeriсап Аntieuolutioпism lr ID proponеntsсan always alэlе сomplехitу of thаt struсturе еm to ignorе struсturеs that arе r m i d d l ее a r o r г h е a v i a n w г i s t tood еvolutionаry history (GishIrsе,thе inaЬility to rеfutе IС Ьy 'h Ьut a wеaknеss. Sсiеnсе pro;provеd'not Ьy proving еxplanauсеd a largе numЬеr of Ьooks 's Оrigiп, thе Ьulk of thеm srnсе lасh Boх and DеmЬski's 1998 , howеvеr,must Ье сlassifiеd as ran sсiеntifiс;it is геvеaling that uсh аs IntеrVarsity Prеss' Bakеr ious, sinсе ID's сlaim to Ье аЬlе struсturеswould imply that its rat arе Ьеing invеstigatеd in thе rld Ье in sсiеntifiсjournals, еspеr Ьiоlogy, Ьut hеrе ID has bееn rt a sесular univеrsity (Lеhigh) j o u r n a l so n s с i е n t i f i сt o p i с s u n ring or attеmptingto puЬlish rе1е most prominеnt ID advoсatеs (s rathеr than sсiеntifiс iournals. kind of Ьlas6 aЬout submitting / o y е a г st o g е t t h i n g s i n t o p r i n t . nd fаstеr Ьy writing a Ьook and sеll wеll. I gеt a royalty. And thе ,8). rеsеntеdаt асаdеmiс сonfегеnсеs gеnеraldisсussion,аrе rеfinеd to iеntifiс iournals, aftеr whiсh thеy шs.Aссording to an artiсlе in thе kеd why hе is not building his lеl at profеssionalmееtings of сеll onds that hе prеfеrsothеr vеnuеs. -ingsarе еffесtivе forums for prе-

: 0 0 18, ) .

Oponеntsсontеnd that thеir viеws r r n a l sЬ е с a u s еr h е y r е j е с t t h е s t a Ьanishеdfrom puЬliсation (as thе is and punсtuatеd еquilibria wit, r еt h a n t h е u s u a l a m o u n t o f s u p plausiblеrеason for thе dеarth of

ID artiсlеs in thе sсiеntifiс litеraturе is thе сonstraints that arе imposеd on doing sсiеnсе by ID's foundational сlaim, whiсh is that natural сausеs сannot produсе (sоmе)natural phеnomena. Sinсе sсiеnсе еxplains through natural сausеs,thе thеory thаt undеrliеs ID makеs it rathеr diffiсult to do any .lfhat would ID rеsеarсh in Ьiology (rathеr than thеology) aсtual rеsеarсh. look likе othеr than attеmpting to show, as сrеation sсiеnгistsattеmptеd to show, that natural proсеssеssuсh as thosе involvеd in еvolution arе inadеquatе to aссount for thе origins and histoгy of lifе? Thеrе is no historiсal sсеnarioprеsеntеdЬy ID advoсatеs' so thеrе arе no faсt сlaims to tеst. If thе thеory Ьеhind ID disсouragеssсiеntifiс aсtivity and thеrе arе no faсt сlaims, thеrе should Ье no surprisе that thеrе arе no artiсlеs in thе sсiеntifiс litеraturе. DеmЬski himsеlf has сommеntеd, pеrhaps with somе frustration, on thе laсk of progrеss in produсing a sсiеntifiс foundation for ID and suggеsts ..dеsign-thеorеtiс framеwork'' suсh as сomparing a modеl еmployinga vaguе of tесhnologiсаl innovation dеvеlopеd Ьy Russian еnginееrs with Ьiologi. сal systеms (DеmЬski 2002). Prеsumably DеmЬski аntiсipatеs that Ьiologiсal phеnomеna will rеsеmЬlе еnginееrеd systеms (dеsignеd),and that this will in somе Way support ID, in dеfianсе of сopious litеraturе that points out that Ьiologiсal phеnomеnа arе organiс in сomposition rathеr than artifaсtual. Although thе sсiеntifiс сommunity has paid morе attеntion to ID than to сrеation sсiеnсе, thеrе is not an еxtеnsivе anti.ID litеraturе in sсiеntifiс journаls' primarily Ьесausе ID has Ьееn promotеd almost еxсlusivеly in Ьooks writtеn for thе gеnеral puЬliс, DеmЬski's Thе Dеsigп Iпfеrепce bеing a notaЬlе ехсеption. As a rеsult, most of thе puЬlishеd сritiquеs of Dеmbski and Bеhе arе Ьook rеviеws, as сitеd еarliеr, although thеrе arе a fеw artiсlеs in philosophy or mathеmatiсs journals-rarеly in Ьiology journals-that disсuss ID (Wilkins and ЕlsЬеrry 2001; Shanks 1999; SoЬеr 2002; Pеnnoсk 2003). Thеrе is a growing numЬеr of books Ьеing puЬlishеd that spесifiсally сritiquеID on sсiеntifiсand/or philosophiсa1grounds (Pеnnoсk 1999,2ООI; Forrеstand Gross 2004; Shanks 20041K. R. Millеr 7999iK. B. Мillеr 2003; Young аnd Еdis 20О4). Onе сan find tесhniсal analysеs and еvеn livеly disсussions among ID advoсatеs and сritiсs taking plaсе on thе Intеrnеt, howеvеr (е.g.,www.pandasthumЬ.org; Matzkе 2004; Gishliсk 2003; Еlsbеrry aпd Shallitt 2003; \Wеin 2002). For all thе сlaims that ID advoсatеs makе for thе sсiеntifiс validity of thеir еntеrprisе,еvеn a Ьriеf сomputerized sеarсh of sсiеntifiс journals rеvеals that no onе is applying thе сonсеpts of СSI or irrеduсiЬlе сomplеxity to undеr. stand oг ехplain Ьiologiсal phеnomеna (Gilсhrist 1'9971Forrеst and Gross 2004|. Thе Ьurdеn of proof rеmains on thе pгoponеnts to dеmonstrаtе that thеir position is sсiеntifiсаlly valid and usеful. Mеanwhilе, rеsеarсh in еvolutionary Ьiology appеars to Ье in a partiсulaгly produсtivе pеriod, with nеw insights and undеrstandings Ьеing provided not only from thе disсovеry of nеw fossil rеmains Ьut also from molесular Ьiology, еspесially as аppliеd to d е v е l o p m е n t аЬl i o I o g y .

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Amеriсап Aпtiеuolиtionism .William сULТURAL RЕNЕWAL. DеmЬski has writtеn, ..Intеlligеnt dеsign is thrее things: а sсiеntifiс rеsеarсh program that invеstigatеs thе еffесts of intеlligеnt сausеs;an intеllесtual mоvеmеnt that сhallеngеsDarwinism and its naturalistiс lеgaсv; and a wav of undеrstanding divinе aсtion'' (DеmЬski 1999,1'3). Although thе sсiеntifiс rеsеarсh program of ID has Ьееn unsuссеssful, thе Ьulk of thе еffort еxеrtеd Ьy thе ID movеmеnt is dirесtеd toward tЬe сultиrаI rепеLuаIсomponеnt hintеd at in Dеmbski's sесond сlausе: thе еffort to rеplaсе ..naturalism''-in thе ID worldviеw' tantamount to athеismwith Сhristian thеism. As suggеstеd Ьy Ьoth thе inadеquaсy of its sсiеntifiс rесord and thе titlеs of its organizing сonfеrеnсеs, thе ID movеmеnt is in faсt primarily сonсеrnеd with thе Сhristian rеligion and its сonfliсt with matеrialist philosophy-thе philosophy that thеrе arе only matеrial (mаttеr аnd еnеrgy) phеnomеna in thе univеrsе; thеrе is no supеrnatural rеality. To dеfеat sесularism in modеrn soсiеty, thе ID movеmеnt attaсks sсiеnсе through еvolution. Thе attaсk, signifiсantly еnough, is n.Jt primarily through sсiеntifiс еvidеnсе Ьut through philosophiсal and еvеn statistiсаl argumеnts' though thеsе argumеnts arе fеlt to Ье thin Ьy philosophеrs and proЬaЬility thеorists. To undеrstand how thе ID advoсatеs rеason rеquirеs a short digrеssion intо thе natrrrе of sсiеnсе as it is praсtiсеd Ьy sсiеntists today. Although philosophеrs of sсiеnсеrеadily arguе aЬout thе dеfinition of sсiеnсе and еvеn whether sсiеnсе сan Ье сlеanly distinguishеd from othеr wаys of knowing, thеsе argumеnts arе not vеry important to thе асtual еntеrprise of sсiеnсе as it is praсtiсеd Ьy sсiеntists' who tеnd not to think muсh aЬout thе philosophiсаl niсеtiеs. It would Ье rеlativеly еasy to gеt sсiеntists (and proЬaЬly еvеn philosophеrs of sсiеnсе)to agrее on a сouplе of Ьasiс еlеmеnts that сharaсtеrizе sсiеnсе, еvеn if suсh еlеmеnts did not fully dеmarсatе sсiеnсе from othеr еpistеmologiеs. Sсiеnсе is an еffort to undеrstand thе natural or matеrial world-thе world of mattеr and еnеrgy and thеir intеraсtion. It is, therеforе,not сapaЬlе of еxplaining thе phеnomеnon of rеligion: the purportеd еxistеnсе of a transсеndеntal rеality Ьy dеfinition not limitеd to thе matеrial univеrsе. Sсiеnсе is in this sеnsе a limitеd еndеavor: it is limitеd to matеrial phеnomеna. Sсiеntists would also agrее that thе еssеnсе of sсiеnсе is testing еxpianations against thе natural world; an еxplanation Ьasеd only on inspiration. rеvеlation, сrеativity' oг imagination would not Ье a sсiеntifiс ехplanation, although a sсiеntifiс еxplanation might Ьеgin that way. Only after сonfirmation through tеsting would it Ьесomе a sсiеntifiс ехplanation. Thе famous story of how Friеdriсh Kеkul6 сamе to disсovеr thе сirсular struсturеof Ьеnzene aftet drеaming of a snakе сhasing its tail illustrаtеs this wеll: it took vеrifiсation-tеsting thе еxplanation against thе natural world-to еstaЬlish a sсiеntifiс ехplanation. Kеkцl6 did not stop with thе drеam. It is also likеly that sсiеntists would agrее that a major сomponеnt of tеsting is holding сеrtain variablеs сonstant in ordеr to mеasurе thе еffесt
minimalist dеfinition f. nonеthеlеss сontains с} Intеlligеnt Dеsign сrt ural сausеs, known as r iсal naturalism. Philosо opposеd to Сhristian t сould Ье Ьroadеnеdto l uralism сould Ье aЬanс is pеrсеivеd as its stror (Мorеland 19941Scott God (or ..intеlligеnсе joЬ, is a kеy goаl of ID Тhеistiс sсiеnсе is Ьа enсe and opеrаtion sсiе mal,'' mеthodologiсall sсiеntifi с ехplanations. singular, unrеpеataЬlе aЬout whiсh supposеd triЬution of сausality tс еration sсiеnсе.a Еvolution, thеn, is a сausе of its matеrialis mеthodologiсal and ph as a thfеat to Сhristiaп сlеarly is onе of thе m. Dаrъuiп on Тriаl lvas tl Johnson рromotеs a l taсkеd as a mеans tс) rееstaЬlishmеnt of а Сl mony of thеistiс sсiеnс also Ьееn instrumеntal сommitmеnt to any faс a waУ of avoiding thе р of The Муstеrу of Lifе'. son сonсеntratеs on th natural sеlесtion)to еx1

So thе quеstion is: ..[ you now sее full.flеd important thing"-tl Gеt thе BiЬlе аnd thе not Want to raisе thе mеnt in suсh a way tJ in a way that tеnds tt trating on, "Do you r it on its own?'' аnd r

Аmericаn Апtiеuolutionism i writtеn' ..lntеlligеntdеsign is lt invеstigarеsthе еffесts of int сhallеngеsDаrwinism аnd its .ding divinе aсtion'' (DеmЬski lгogrаmof ID has Ьееn unsuсD movеmеnt is dirесtеd toward )еmbski'ssесond сlausе:thе еflviеw,trrntаmountto athеisn-lthе inadеquaсy
minimalist dеfinition for virtually all sсiеntists.But this minimаl dеfinition nonеthеlеssсontains сhаraсtеristiсsthat arе opposеd by ID advoсatеs. IntеlligеntDеsign сrеationistsЬеliеvеthat thе rеstriсtion of sсienсе to natural сausеs,known aS nеthodologiса1 naturalism, lеads pеoplе to philosophiсal naturalism.Philosophiсal naturаlism is, of сouгsе' thе еnеmy Ьесausеit is opposеd to Christian thеism' If a powеrful сultural еntеrprisе likе sсiеnсе сould Ье Ьroadеnеdto inсludе God's intеrvеntion' and if mеthodologiсal naturalism сould Ье aЬandonеd, thеn philosophiсal naturalism would losе what is pеrсеivеdas its strongеstsupport. Thе еstaЬlishmеntof ..thеistiсsсiеnсе'' (Мorеland 1994; Scott 1998), whiсh pеrmits thе invoсаtion of thе hand of Gоd (or ..intеlligеnсе'')whеn natural еxplanations arе inаdеquatе for thе joЬ, is a kеy goal of ID сгеationism. Thеistiс sсiеnсе is Ьasеd on thе сonсеpt of a diсhotoпry Ьеtwееn origiп scieпсе and operаtion sсiеtlсе, thе lattеr Ьеing ID proponеnts'tеrm for thе ..normal''' mеthodologiсally matеrialistiс sсiеnсе usеd in thе v:rst mаjority of sсiеntifiсехplanations. origin sсiеnсе is dеfinеd аs thе sсiеnсе usеd to ехplain singular, unrеpеatablе еvеnts (thе origin of lifе, for еxample)' hypothеsеs about whiсh supposеdly arе untеstaЬlе and thus r.rnfalsifiablе.Thеrеfore' attriЬutionof сausality to God is aссеptaЬlеin origin sсiеnсе,though not in op_ еration sсiеnсе.a Еvolution, thеn, is a stalking horsе for an attaсk upon sсiеnсе, whiсh Ьесausе of its matеrialistiс Ьasе (ID сrеationists do not distinguish Ьеtwееn mеthodologiсaland philosophiсаl naturalism in any praсtiсal sеnsе)is sееn as a thrеat ro Сhristiarr thеisnr. Thе ID advoсatе who nrakеs thеsе links most сlеarly is onе of thе most prolifiс ID authors, Phillip Johnson, whosе 1991 Dаrluilt oп Тriаl was thе first ID puЬliсation to attraсt widе puЬliс notiсе. ..wеdgе''' whеrеin еvolution is atJohnson promotеs a stratеgyhe сalls thе taсkеd as a mеans to сhallеngе naturalism, thus paving thе way for thе rееstaЬlishmеntof а Сhгistiаn sеnsiЬiiity in Amеriсan сultuге and the hеgеmony of thеistiс sсiеnсе (Johnson 1997i Forrest and Gross 2004). Hе has also Ьееn instrumеntai in promoting a puЬiiс Prеsеntаtionof ID that аvoids сommitmеntto any faсtual сlaims, suсh as a youn8 or old agе of thе еarth' as a way оf avoiding the pitfalls of сrеation sсiеnсе.Instеad,as did thе aцthoгs of Тhe Муsterу of Life's Оrigiп and Оf Pапdаs аnd Pеople Ьеforе him, Johnson сonсеntratеson thе supposеd inadеquaсy of natural сausеs (еspeсially nаturalsеlесtion)to ехplain thе origin arrd divеrsity of living things: So thе quеstion is: ..How to win?'' Тhat's whеn I bеgan to dеvеlop what you now sее full-flеdgеdin thе ..wеdge'' stratеgy:..Stiсk with thе most important thing''-thе mесhanism and thе Ьuilding up of information. Gеt thе BiЬlе аnd thе Book of Gеnеsis out of thе dеЬate Ьесausеyou do not Want to raisе thе so-сallеd BiЬlе-sсiеnсеdiсhotomy. Phrаsе thе argu. mеnt in sцсh a way that you сan gеt it hеаrd in thе sесular aсadеmy and in a way that tеnds to unify thе rеligious dissеntеrs.That mеans сonсеntrating on, ..Do you nееd а Сrеator to do thе сrеating' or сan naturе do it on its own?'' and rеfusing to gеt sidеtraсkеd onto othеr issuеs,whiсh

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Аmеricаn Antiеuolutionisnl pеoplе arе always trying to do. Thеy'll ask, ..W.hat do you think of Noah's flood?,' or somеthing likе that. Nеvеr Ьitе on suсh quеstions Ьесausе thеy'll lead you into a rrасklеsswastеland and you'll nеvег gеt out of it. (Kushinеr 2000, 40) Bесausе it doеs not prеsеnt an altеrnativemodеl to еvolution, and Ьeсаusе of its rеluсtanсе to mаkе faсt сlaims, thе сontеnt of ID thus dеvolvеs to thе rеitеration of argumеntslong ago raisеd Ьy thе young-еarthсrеationists:gaps in thе fossil rесord, thе inadеquaсy of natural selесtionto produсе еvolution..proЬlеms'' of thе СamЬrian ary сhangе, thе ехplosion, and sо on. As is thе ..с
of thе univеrsе at one til arе forсеd to support tht idеnсе аgainst еvolutiоn a frеquеrrtlyrеworkеd lil suсh as gаps in thе foss law of rhеrmodynamiсs imрossiЬility of dеvеlop dom variation and natu living organisms'' (IСR

i d е n с е a g а i n s tе v o l u t i o n who arе puzzled that un appеaranсе of СamЬrian sеlесtivе mесhanisms iп thеoгy oг rеаsons to rеjе Tеaсhing thе ..еvidеn mеnt сlausе proЬlеm gеl stratеgy is thеrеforе favс who arе opеrating in th( for еxamplе, has сomе tt ID Ьut rathеr to tеaсh th

Thе Futurе of Antit

Sсott and Branсh havе гt thгее pеriods of Amеriс сontrovеrsy today as thr 282). Аt any givеn timе o f t h с с r е a t i o n i s tp о s i t i o

1. Еvolution is wеak o aЬandoning in inсrе 2. Еvolution is inhеrел ..Ьа 3. It is only fair to o r l n t е l I i g е n tD е s i g good pеdagogy to .. ..wеaknеssеs''or ..е dесidе.''

Thеsе thrее thеmеs w trovеrsy in thе futuге. Iй studiеs of antiеvolutiсln stгongеsr motivation for 1980s аnd еarly |990s, сrеаtionism in favor of t еral puЬIiс and, еspесi Both сrеation sсiеnсеап

Amеriсап Aпtieuolutionism sk, "'S7hat do you think of еr Ьitе on suсh quеstions Ьеland and yоu'll nеvеr gеt out rodеl to еvоlution, and Ьесausе tеnt оf ID thus dеvolvеs to thе е young.еaгthсrеationists:gaps sеlесtionto produсе еvolutionеxplosion' and so on. As is thе ..сontrivеd dualism,'' to quotе rn Ье shown to Ье untruе, ID is

rl-timе laws,.tJ7еndеllBird, who iuprеmе Сourt, gamеly advisеd night still Ье lеgally taught if it 987). Нis pеrspесtivе was not гts who intегprеtеd Еdшаrds as and сrеationism; Еdшаrds has rts in dесisions that havе struсk i f o r n i аt o Ь r i n g с r е а t i o n s с i е n с е alia and signеd Ьy Justiсе Rеhnrasquitе сompatiЬlе with еxtant inсluding thosе who arе Christесular mattеr, to havе whatеvеr пtion prеsеntеdin thеir sсhools, 'hatеvеrsсiеntifiс еvidеnсе thеrе е IСR sеizеd upon this immеdi. ;hеd. Есhoing Sсalia' it еnсour..In thе mеantimе' t еvolution: gly еnсouragеdat lеast to Strеss st еvolution in thеir сlassеs (not l t i o n a r ym е с h a n i s m ,Ь u t a g a i n s t rесognizе thеsе as еvidеnсеs and 'gumеntsfor a partiсular datе of 7\. idеnсе against еvolution'' is еasy nd that thеrе arе only two possi;ifiс vеrsion of Christian spесial all thе othеr origin storiеs from lеm it is logiсal to infеr that еvi. tionism.Praсtiсal сonsidеrations that support thе spесial сrеation

of thе univеrsе at onе timе, in its prеsеnt form, so сrеation sсiеnсе advoсatеs arе forсеd to support thеir viеw with a nеgativе argцmеnt' that of allеgеd еvidеnсеаgainst еvolution. Thе сontеnt of сrеation sсiеnсе primarily сonsists of a frеquеntly rеworkеd litany of argumеnts prеsеntеd as disproving еvolution, suсh as gaps in thе fossil rесord, thе supposеd inсompatiЬility of thе sесond law of thеrmodynamiсs with a gradually inсrеasing сomplехity of lifе' thе impossiЬility of dеvеloping phylum-lеvеl Ьody-plan diffеrеnсеs through random variation and natuгal sеlесtion, and thе ..vast information сontеnt of living organisms'' (IСR 1'987).It pеrhaps goеs without saying that suсh ..еvidеnсеagainst еvolution,' gеneratеsЬlank looks from еvolutionary Ьiоlogists, who arе puzz|еd that unsolvеd arеas in sсiеnсе suсh as thе origin of lifе, thе appеaranсеof СamЬrian Ьody plans, or thе rеlativе rolе of sеlесtivеand nonsеlесtivеmесhanisms in еvolution arе сonsidеrеd wеaknеssеs in еvolutionary theory or rеasons to rеjесt thе infеrеnсе of сommon anсеstry. Tеaсhing thе ..еvidеnсе against еvolution'' avoids thе oЬvious еstaЬlishmеnt сlausе proЬlеm gеnеratеd Ьy ID, whiсh is ..\й/hois thе dеsignеr?'' Thе stratеgyis thеrеforе favorеd among thе morе sophistiсatеd аntiеvolutionists who arе opеrating in thе еarly twеnty-first сеntury. The Disсovеry Institutе, for ехamplе, has сomе to urgе sсhool Ьoards not to rеquirе tеaсhеrs to tеaсh ID Ьut rathеr to tеaсh thе ..strеnsthsаnd wеaknеssеs',of еvolution.

Thе Futurе of Antiеvolutionism Sсott and Branсh havе rеfеrrеd to thrее thеmеs that havе run throughout thе thrее pеriods of Amеriсan antiеvolutionism and сontinце to illustratе thе сontrovеrsytoday as thе ..pillars of сrеationism'' (Sсott and Branсh 200З' 282). Аt any givеn timе in this history, thеsе thrее argumеnts havе Ьееn part of thе сrеationist position: 1. Еvolution is wеаk or unsupportеd sсiеnсе that sсiеntists arе aЬandoning in inсrеasingnumЬеrs. 2. Еvolution is inhеrеntly antirеligious. 3. It is only fair to ..Ьalanсе''thе tеaсhing of еvolution with сrеationism or IntеlligеntDеsign. A vaгiant of thе ..fairnеss''argumеnt is that it is good pеdagogy to ..Ьalanсе'' thе tеaсhing of еvolution with ..wеaknеssеs'' ..еvidеnсе or against'' еvolution ..and lеt thе сhildrеn dесidе.'' Thеsе thrее thеmеs will сontinuе to shapе thе сrеationism,/еvolutionсon.Wе trovеrsyin thе futurе. сan illustratе thеm Ьy еxamining somе rесеnt сasе studiеs of antiеvоlutionism. Although rеligion ovеrwhеlms all еlsе as thе stfongеstmotivation for antiеvolutionism' Ьесausе of lеgal dесisions of thе 1980sand еarly 1990s, сrеationists havе downplayеd thе sесond pillar of сrеationismin favor of thе first and third, at lеast whеn addrеssing thе gеnеral puЬliс and, еspесially, puЬliс offiсials suсh as sсhool-Ьoard mеmЬеrs. Both сrеation sсiеnсе and ID proponеnts havе hammеrеd away at thе idеa of

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A m eri сап Апt iеuolutioпism еvolution as wеak sсiеnсе and havе strеssеdthе importanсе of fairnеss' еspесially in tеrms of tеaсhing ..еvidеnсе against еvolution.'' Anothеr trеnd has Ьееn thе ..morphing'' of YЕС to ID to ..еvidеnсеagainst еvolution.,' In a numЬеr of сommunitiеs, pеoplе who arе young-еarth сrеationists bеgan to idеntify thеmsеlvеs as ID supportеrs' thus avoiding thе stigma of сrеation sсiеnсе, whiсh is at Ьеst сonsidеrеd a minority viеw, if not a fringе pеrspесtivе'in Ьoth rеligion and sсiеnсе.IntеlligеntDеsign, on thе othеr hand, is lеss wеll known to thе gеnеral publiс, and Ьесausе of thе vaguenеss with whiсh it is prеsеntеd (making no сlaims aЬоut thе agе of thе еarth, fоr еxamplе), it appеars lеss marginal than сrеation sсiеnсе.Latеr' as a сommunity that is dеЬating еvolution еduсation Ьесomеs fanriliar with ID and its sсiеntifiс stеrility and duЬious сonstitutionality, thе antiеvolutionists oftеn rеtrеat to a fallЬaсk position of ..еvidеnсеagainst еvolulion,'' usually portraying it as a сompromisе that should Ье aссеptaЬlе to аll. Morphing of this sort oссurrеd during thе wеll-puЬliсizеd Kansas statе sсiеnсе standards сontrovеrsy of 1999. сAsЕ sтUDY: KANSAS As a rеsult of еduсation rеform movеmеnts that bеgan in thе 1980s' most Amеriсan statеs havе еstaЬlished еduсational standards for history, mathеmatiсs, sсiеnсе, and other aсadеmiс suЬjесts. Aftеr thе fеdеral No Сhild Lеft Bеhind Aсt of 2001 mandatеd pеriodiс high-stakеs tеsts for studеnts, statе standards took on еvеn morе importanсе. Tеst topiсs would Ье Ьasеd on thе standards; if еvolution wеrе inсludеd in thе standards, thеn it would Ье inсludеd in thе tеsts. Statеs that did not alrеady havе standards or framеworks Ьеgan to dеvеlop thеm in thе 1990s; thе vast majority of thеm inсludе еvolution, though in varying dеgrееs of сompеtеnсy (Lеrnеr 2000). Мany statеs that had ignorеd еvolution prеviously now rеquirе that thе topiс Ье taught. A good dеal of thе antiеvolution aсtivity of thе past fеw yеars has Ьееn dirесtеd аt thе еstaЬlishmеnt of statе sсiеnсе еduсation standards: сrеationists opposе thе inсlusion of еvolution in thе standards,or try to gеt ID addеd, or try to gеt ..еvidеnсе against еvolution'' inсludеd. Muсh as thе rеturn of еvo. lution to thе сurriсulum in thе mid-1960s gеnеratеda сrеationist Ьaсklash' so also has thе standards-Ьasеd rеquirеmеnt that еvolution Ье taught gеnеratеd its own Ьaсklash. Kansas undеrtook to writе sсiеnсе еduсation standards in 1999. А 27pеrson сommittее of mastеr tеaсhеrs and sсiеntists was appointеd Ьy thе Kansas Dеpartmеnt of Еduсation and thе Kansas Board of Еduсation to draft standards that thеrеaftеr wеnt out for puЬliс сommеnt' wеrе rеvisеd, and wеrе ultimatеly suЬmittеd to thе Ьoard of еduсation for approval. This proсеdurе was prolongеd, сontеntious, and Ьittеrly fought. A сonsеrvativе Ьloс of fivе sсhool-Ьoard mеmЬers had сomе to powеr in thе 1996 state sсhoolЬoard еlесtion and сlashеd with thе fivе modеratе sсhool-board mеmЬеrs ovеr many issuеs. Whеn thе sсiеnсе еduсation standards сamе up for сonsidеration. it was an еasy orеdiсtion that еvolution wоцld Ье a сontеntiousissuе.

Indееd, сonsеrvativеso1 that thеy did not look k t h е s t a n d a r d s( С u n n i n g

D u r i n g г h еs p r i n ga n с tеrs to thе еditors argur Inсlusion of еvolution . vеlop quеstions for thе s in thosе еxams' it wаs rooms. Tеaсhers and sс havе a prominеnt plaсе standards thаt wаs sub thе National SсiеnсеЕd Aсadеmy of Sсiеnсеs,ar Sсiеnсе (AAAS) Bеnсhп bееn influеntial in shap NSЕS and thе Bеnсhma inсludе it throughout th In midsummer 1999 standards сommittее'sd l а r g е | yЬ е е n w r i t t е n b y ation for Mid.Amеriсa, of St. Louis. AЬrams's st or сapablе tеасhег wor сludеd muсh aЬout how puЬliс hеarings oftеn ml draft of thе standards сt сompгomisеdraft thаtit draft сompromisеd bеtl thosе who wаntеd the ,A iсs suсh аs thе Ьig Ьang standards and adding sс of sсienсе.'

A loud huе and сry еr papеrs' tеlеvision, and r tеlеvision talk shows, ; Kansаs Wizаrd of Оz ir Kansas suffеrеd at thе l thе nехt sсhool-Ьoard еl atе majority swiftly abar adoptеd thе final draft 1 thе nеw Ьoard took offi< Thе Kansas сontrovе сrеationism, thе сlаim tt ProЬaЬly bесausе thе п еarth сrеаtionists' and t сludеd in thе sсiеnсеsta

Аmеriсап Aпtiеuolutionism e importanсеof fairnеss,еspеrolution." / Е С t o I D t o ' . е v i d е n с еa g a i n s t lplе who arе young-еarth сrеsupportеrs'thus avoiding thе rsidеrеda minority viеw' if not . IntеlligеntDеsign, on thе othеr , and Ьесausеof thе vaguеnеss aЬout thе agе of thе еarth, for on sсiеnсе.Latеr, as a сommuomеs fanriliar with ID and its ity' thе antiеvolutionists oftеn 3ainstеvolution,'' usually por'ссеptablеto all' Мorphing of Kansas statе sсiеnсе standards

tlrat bеgan in thе 1980s' most l standаrds for history, mathеAftеr thе fеdеral No Сhild Lеft -stakеs tеsts for studеnts, statе st toPiсs would Ье Ьasеd on thе stаndards, tlrеn it would bе in.havе standardsor framеworks rnajority of thеm inсlцdе еvolurсy (Lеrnеr 2000). Many statеs еquirе that thе topiс bе taught. thе past fеw yеars has Ьееn dil u с а t i o n s t a n d a r d s :с r е a t i o n i s t s lards, or try to gеt ID addеd, or Jеd' Мuсh as thе rеturn of еvoэnеratеda сrеationist bасklash, that еvolution Ье taught gеnеrtion standards tn 1999. ^ 27сiеntistswas appointеd Ьy thе rsasBoard of Еduсation to draft iс сommеnt, wеrе rеvisеd, and luсationfor approval. This proзгly fought' A сonsеrvativе Ьloс powеr in the 1'996 statе sсhoolLodеratеsсhool-Ьoard mеmЬеrs n standardsсamе uP for сonsid. o n w o u l d Ь е a с o n t е n t i o u si s s ц е .

Indееd,сonsеrvativеson thе Ьoard lеt it Ье known rathеr еarly in thе proсеss that thеy did not look kindly on thе inсlr-rsionof еvolution in thе first dгaft of the standards(Сunningham 1999). During thе spring and summеr of 1999 Kansas nеwspapеrs wеrе full of lеttеrsto thе еditors аrguing for and against еvolution in thе sсiеnсеstandards. Inсlusion of еvolution was impoгtant: thе standards would bе usеd to dеvеlop quеstions for thе statе gr:rduаtionеxаms. If еvolution Was not inсludеd in thosе еxams) it was a safе Ьеt that it would not Ье taught in thе сlassrooms. Tеaсhеrs and sсiеntists thеrеforе Wеrе vеry сonсеrnеd that еvolution havе a prominеnt plaсе in thе sсiеnсе eduсаtiorr standards. The draft of thе standardsthat wаs suЬmittеd foг puЬliс сommеnt in April 1999 paral|e|ed thе National SсiеnсеЕduсation Standards (NsЕs), produсеd Ьy thе Nationаl Aсadеmy of Sсiеnсеs, and thе Arnеriсan Assoсiation for thе Advanсеmеnt of Sсiеnсе (AAAS) Bеnсhmarks for Sсiеnсе Litеraсy, two doсumеnts that havе Ьееn influеntial in shaping sсiеnсе standards aсгoss thе сountry. Both thе NSЕS and thе Bеnсhmаrks trеat еvolution as an importurntsсiеntifiсidеа and inсludе it througlrout thе sсienсе сurriсulum. In midsummer 1999 sсhool-Ьoard mеmЬеr Stеvе AЬrams сountеrеd thе standardsсommittее's draft with ir rеplaсеmеnt standards doсumеnt that had largеlvЬееn writtеn Ьy Tom Willis, thе hеad of thе Сrеation Sсiеnсе Assoсiа r i o n f o r М i d - А n l е г i с a ' а y o u n g . е а r t hс r е а r i o n i s to r g а n i z a t i o no p е r a t i n gr l u t of St. Louis. AЬranrs's standards inсlцdеd sеvеral provisions that any sсiеntist or сapaЬlе tеaсhеr would сonsidеr highly quеstionaЬlе and of сoursе inсludеdmuсh aЬout lrow еvolutiorrwas unrеliaЬlе sсiеnсе.Aftеr a summеr of puЬliс hеarings oftеn markеd Ьy Ьittеr сontrovеrsy' the Ьoard took thе final draft of thе standards сommittее аnd thе AЬrams standards and produсеd a сompromisеdrаft that it aссеptеdas thе statе standardsin August 1999. This draft сompromised Ьеtweеn thosе who wantеd еvolution to Ьe taught aпd thosеwho wantеd thе Abrams draft Ьy rеmovirrgеvolution аnd rеlatеd topiсs suсh as thе Ьig Ьаng, соrrtinеntal drift, i.rndradiomеtriс dating from thе standardsand adding somе languagе from AЬrams's draft aЬout thе naturе of sсiеnсе. A loud huе аnd сry еnsuеd,not only in Kansas' Ьut also in national nеwspapеrs'tеlеvision' аnd radio. Kansas Ьесirmеthе butt of jokеs сln iatе-night tеlеvision talk shоws, and еditorial сartoonists had a fiеld day with thе Kansas Wizаrd сlf oz tсonogrаphy of Dorothy and Toto. Thе ridiсulе that Kansas suffеrеd at thе hands of thе national prеss stung suffiсiеntly thаt in thе nехt sсhооl_Ьoaгdеlесtion thе сonsеrvativеslost thrее sеats.Thе modегatеmajoгity swiftlv аЬandonеd thе сompromisе standards and on a 7-З vote adoptеd thе final draft prоduсеd Ьy thе standards-writing сommittее whеn thе nеw board took offiсе in FеЬruary 2001. Thе Kansas сontrovеrsy illustгirtеsquitе сlеarly thе first of thе pillars of сrеationism'thе сlаim that еvolutiorris wеak or inadеqiratеsсiеntifiс thеory. ProЬaЬly Ьесausе thе most aсtivе antiеvolutionists in Kansas Wеrе youngеarthсrеаtionists,and Ьесausесrеation sсiеnсе had no сhanсе of Ьеing inсludеdin thе sсiеnсеstandards,thе third, or fairnеss,pillar did not еntеr into

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Аmeriсап Aпtieuolutionism thе сontrovегsy.Howеvеr' timе nrarсhеson, аnd sсhool boards сhangе сompоsition: although in thе 2000 еlесtion modеratеs prеvailеd, in 2002 thе Ьoard onсе again was dеadloсkеd with a 5_5 ratio of сonsеrvativеsto modеfatеs. Thе sсiеnсе еduсation standards wеrе lеft alonе during tlrat tеrm, Ьut thе prеsеnсе of a 64 сonsеrvаtivе majority aftеr thе 2004 еlесtions mеant that thе sсiеnсе standards rеvision that took plaсе in 2005 was highly сontеntious. Сrеationist-oriеntеd sсhool board mеmЬеrs Supportеd standaгds that did not dirесtly сall for thе tеaсhing of сrеirtion sсiеnсе or ID, Ьut for thе 'Гhе standards wеrе passеd in tеaсhing of lD_inspirеd сritiсisms of еvolutior.r. NovеmЬеr of 2005 (..Antiеvolution Standards Adoptеd in Kansas'' 2005) and wеrе widеly сritiсizеd Ьy loсal tеaсhеrs and sсiеntistsаnd national sсiеnсе and еduсational organizаtions, inсluding thе AAAS and thе National Aсadеmy of Sсiеnсеs(..Ехposing tЬе Flaws of thе Kansas SсiеnсеStandards'' 2006). Thе nехt yеar, howеvеr' Was an еlесtion yеar, and two сonsеrvativе Ьoard mеmЬеrs lost thеir sеats (..Thе Pеndulum Swings in Kansas'' 20О6).In ear|у 2О07 thе rесonstitutеd, mоrе modеratе sсhool Ьoard rеsсindеd thе 2005 standards аnd adoptеd standards that nеithеr dеnigratеdеvolution nor inсludеd somе form of сrеаtionism (..Еvolution Rеturns to Kansas'' 2007). Kansas is also an ехаmplе of thе morphing of young.еarthсгеаtionistsinto ID сrеationists. A numЬеr of antiеvolutionists who aсtivеly opposеd tЬe 1999 Kansas standards havе сast thеmsеlvеsas ID supportеrs.John Сalvеrt is a good еxamplе: hе organizеd thе IntеlligеntDеsign Nеtwork (IDNеI), an or. ganization thаt hаs sponsorеd arrnual сonfеrеnсеspromoting ID in Kansas and in somе othеr statеs.Саlvеrt hаs Ьесomе a сirсuit ridеr for ID, travеiirrg to ohio, Nеrv Меxiсo, Gеorgia, Wеst Virginia, аnd Montana to promotе iг. Thе Disсovеry lnstitutе' howеvеr, has сomе to disсouragе thе promotion of ..еvidеnсе against ID in thе сlassroom in favor of tеaсhing еvolution.'' Thе Disсovеry Institutе has promotеd this approaсh sinсe tЬe 2ОО2 Ohio sсiеnсе еduсation standards сontrovеrsy' during thе сontеrrtious2005 rеvision of thе Kansas stаndards.and еlsеwhеrе' сAsЕ sтUDY: RoSEV|LLЕ' сALlFoRNIA Although statе Ьo:rrd of еdцсation сontrovеrsiеsаnd antiеvolutionism lеgislation tеnd to gеnеratеmorе Prеss сovеragе'thе majority of arrtiеvoiutionisrn inсidеnts oссur аt thе loсal sсhool-Ьoard lеvеl' A сontrovеrsY in Rosеvillе, Сalifornia, similarly illustratеsthе pillars of сrеаtionism, as wеll as thе morphing of YЕС into ID into еvidеnсеagainst еvolution. Rosеvillе is a сommunity of approхimatеly 92,000 loсatеd 20 rnilеs northеast of Saсrаmеnto in north сеnrrаl Сalifornia. A suЬstantial сonsеrvativе Christiаn сommunity thеrе tеnds to еlесt sсhool-Ьoard mеmЬеrs who shаrе ..сulturе-war''сontrovеrsiеsin Rosеvillе thеir viеws. Thеrе havе Ьееn many ovеr thе past sеvеral yеars' inсluding sех еduсatiоn as wеll as еvсllution. Thе most rесеnt еvolution сontrovеrsy Ьеgan in thе sr'rmmеrof 2003 whеn highsсhool Ьiology tеxtbooks wеrе Ьеing rеviеwеd for adoption. A loсal сitizеn, Larry Саldwеll, сomplainеd that thе tехtЬooks, all stаndагd сommеrсial

puЬlishеr offеrings,1 ..sсiеn providе any Сaldwеll first pгopor Ьooks (Rosеn 2003t pоsal to promotе tеa rесommеndеd a vid JonathzrnWеlls's boс vidеo, Uпloсkiпg th YЕC diatriЬе Ьy Jon l u t i с l п ( 1 9 9 9 ) .A u Ь i r !Иitnеssеs, Lifе: Нot towеr BiЬlе and Trzr Instruсtionirllnatе сommunitiеs, must l tors. To givе thеir from loсal univеrsit mittее rеportеd to th Rosеvillе сurriсuluг sсiеnсе. In SеptепlЬ Ьу thе еvaluation с whеthеr or not to us might possiЬly rеsul thеy had Ьееn rеjесt Crеationists on th еvolution rеsotlГсес als сritiсizing еvсllu tеaсhеrs сould not Ьс studеnts сould go to protеstеd that thеv h support thе сuгriсul want to wastе monс unrеlatеd to thе nее soЦrсе сеntеrs wеrе l Саldwеll nехt attе lrе сallеd Quality Sсi ..strеngtЬs irrg of an< poliсiеs that hаvе to QSЕ сontinuеd ovеr Mаy 10, 2004, in v twо hours. A pеtitiс opposing thе poliсy pеоplе who tеstifiеd In Junе 2004 thе сrеаtionism in Rosе haps Ьесausе of сor arguing ovег сrеirti

A m еri сап Aпti еuolu titlпi sm and sсhool Ьoards сhangе сomldеratеsprеvailеd, in 2002 thе 5 ratio of соnsеrvativеsto mod: lеlt alonе during that tеrm, Ьut . аftеr thе 2004 еlесtions mеant < plaсе in 2005 was highly сon. l mеmЬеrs supportеd standards rеаtionsсiеnсеor ID, but for thе ln. Thе standardswеrе passеd in rrds Adoptеd in Kansas'' 2005) ; and sсiеntistsand national sсi_ ing tЬе AAAS and thе National lf thе Kansas SсiеnсеStandards'' j t i o n y е a r 'а n d t w o с o n s е r v а t i v е lum Swingsin Kansas" 2006). In :аtе sсhool Ьoard rеsсindеd thе nеithеrdеnigratеdеvolution nor :ion Rеturns to Kаnsаs'' 2007). с r е а t i o n i s t si n t o g of young-еаrth ts who aсtivеly opposеd thе 1'999 ID supportеrs.John Сalvеrt is a Dеsign Nеtwork (IDNеI), an orеrеnсеspromoting ID in Kansas rrеа сirсuit ridеr for lD, travеling i n i e ,a n d М o n t а n a t o p r o m o t е i t . е to disсouгagеthе promotion of еvidеnсеagainst еvolution.'' Thе оaсh sinсе the 2О02 ohio sсiеnсе з сontепtious2005 rеvision сrfthе

)RNIA ,еrsiеs;rndantiеvolutior-rismlеgis:,thе majority of antiеvolцtionism lеvеl. A сontrovеrsy in Rosеvillе, lf сrеationism,as wеll aS thе morг еvolution. эly 92,000 loсаtеd 20 milеs north. o г n i а . A s u Ь s t a n t i а lс o n s е r v a t i v е sсhool-ЬoardmеmЬегs who sharе rе-war''сontrovеrsiеsin Rosеvillе duсationas wеll as еvolution. Thе n thе summеr of 2003 whеn highwеd for adoption. A loсal сitizеn, :tЬooks,all standard сommеrсial

puЬlishеroffегings,Prеsеntеdа onе-sidеdtrеatmеntof еvolution аnd did not providе аny ..sсiеntifiс altеrnаtivеs.'' Aссordirrg t
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З 9 0 A m еri сап А пti еuo luti сlпi sm and othеr Ьrеad-and-ЬLlttеrсonсеrns wеrе rrot Ьеing addrеssеd,rhе tssuеwаs not brought r.rpagаin, and in thе Nеsnot ехplаin living things, Ьy dеfault,сrеationismdoеs. ..еvidеnсеagainst Suсh morphing of YЕС to ID to еvolution'' has oссurrеd in ir numЬеr оf сrеatitlrrism/еvolution сontrсrvеrsiеsovеr thе pаst fеw yеars, inсluding сontrovеrsiеs ovеr thе writing of sсiеt-tсееduсation standaгds in Kansas, Ohio, .й/еstVirginia, Nеw Мехiсo, and Minnеsota and in sсhooldistriсt сontrovеrsiеsin DarЬy. Мontana. апd Dovеr. Pеnnsylvania.It is сlеar

that this is whеrе thе сrеatit thе moге obvious ехprеsslo sign and toward thе lеss l against еvolution.'' PRED|ст|oNs FoR

Prеdiсtion is unсеrtain,еsp to hаvе said, Ьut somе fесt ism,/еvolution сontrovеrsy distriсt-сourt judgе Сlarеnс triсt struсk down а tеxtbo( Ьy thе CoЬЬ Сounty, Gе< . . T h i s t е x t Ь o o k с o п t а i n sn faсt, rеgarding thе origin ol with аn opеn mind, studiе P a r е n t si n t h е с o m m u n i 1 2002, Ьut thе сasе took a lс thе sсhool Ьoard hаd a rеl Christianity) in rеquiring tl furthеrmore, undеr Gеorgi tional Ьесausе it rеquiгеdt Thе judgе struсk down thе i n g r е I i g i o n .I n t h е d е с i s i sсholarly аrtiсlеs' as wеll a .,onеol faсt'' languаgе was е m p l o y е dh y a n t i е v o l u r i o n gling out еvolution from а would hаvе thе еffесt of pr< is сrеationism. Thе distriсt pеals vaсatеd thе ruling an< sideration or rеtrial. Thе gr not сonсеrn thе judgе'srulil i n g е v i d е n с е .I n d i s с u s s i o agrееd to rеtry thе сasе.It h plaintiffs' lеgal tеaпl rесеiv pеrt witnеssеs' whiсh strеn rulеd in thеir favor. Thе pll tion of somе of thе attorn sсhool Ьoаrd poliсy rеquiг nation of faсtors was suffiс The sеttlеmеnt was verу fa agrееing nеvеr again to dis orally, or in any othеr forп gia statе standards, whiсh

Amеricаn Aпtieuolutionistп t Ьеingaddrеssеd,thе issuе was r 2004 еiесtion morе modеratе l r r е n tw a v еo f а n r i е v o l u t i o n i s m гt that it is mеrеly a mattеr of еnсе againstеvolution'' risеs in :onsеrvativеsсhоo1-boardmеm-arry Сaldwеll suеd thе distriсt lstitutiOna1rights wеrе infringеd thе distriсt сlaimеd g thеmsеlvеs, d rесеivеda full hеaring, and, in Was spеnt on Сaldwеll's issuеs. l07, and Сaldwеll lost his suit

; phеnonrеnonthat has Ьееn taknЬеrswho arе idеntifiеd with or а d v o с а t е sI.n t г u t h , t h i s i s n o t а .еationistsarе suppoгtеrs of thе аrе young-еarthсrеationists. In ourсеsWеrе offеrеd to thе sсhool [еd with a position, ID, that has is сlеar.Yеt ID is not without its riеsthе impliсation of a dеsigner, s thе Сhristian God. Pеrhaps for from appгoхimatеlythе lаst half rsion of ID in thе сurriсulum Ьut ..strеngthsand wеak;tion'' (or ..tеaсh thе :volution,''or simply o run afoui of thе еstaЬlishmеnt ution,'' although thе nеt еffесt of ion thеologyis сommon to еithеr nсе against еvоlution is еvidеnсе ..limitations on еvolvлlrittеnthat еvidеnсеfor dеsign'' (DеmЬski меak or unsupportеd sсiеnсе that ] е st h е а с с е p r а n с еo f с r е a t i o n i s m : y dеfault,сrеationism doеs. е againstеvolution'' has oссurrеd гovеrsiеsovеr thе past fеW yеars' ,f sсiеnсееduсation standards in э, and Minnеsota and in sсhoolnd Dovеr, Pеnnsуlvania. It is сlеar

that this is whеrе thе сrеationism/еvolution сontrovеrsy is hеadеd: away from thе morе oЬvious еxprеssions of rеligion or сrеation sсiеnсе or Intеlligеnt Dеsign and towаrd thе lеss lеgally vulnеraЬlе stratеgy of tеaсhing ..еvidеnсе against еvolution.'' PRЕDIст|oNs FoR тнЕ (NЕAR) FUтURE Prеdiсtion is unсеrtain, еspесially aЬout thе futurе, as Yogi Bеrra is supposеd to havе said, Ьut somе rесеnt еvеnts may rеshapе thе futurе of thе сrеationism/еvolution сontrovеrsy in thе Unitеd Statеs. In January 2005 fеdеral distriсt-сourtjudgе Сlarеnсе Сoopеr tn Sеlmап u. Сobb Сouпtу School District struсk down a tеxtЬook disсlaimеr ordеrеd insеrtеd into Ьiology Ьooks Ьy thе СoЬЬ Сoцnty, Gеorgia, Board of Еduсаtion. Thе disсlaimеr rеad: ..This tехtЬook сontаins matеrial on еvolution. Еvolution is a thеory, not a faсt, rеgarding thе origin of living things. This matеrial should Ье approaсhеd with an opеn mind, studiеd сarеfully, and сritiсally сonsidеrеd.'' Рarеntsin thе сommunity had suеd thе distriсt and thе Ьoard of еduсation in 2002' Ьut thе сasе took а long timе to сomе to trial. Thе plaintiffs arguеd that thе sсhool Ьoard had a rеligious purposе and еffесt (of promoting sесtarian Сhristianity) in rеquiring that thе disсlaimеr Ье plaсеd in tеxtЬooks, and that furthеrmorе' undеr Gеorgia law' thе sсhool Ьoard's aсtion was unсonstitutional Ьесausе it rеquirеd thе еxpеnditurе of statе funds to promotе rеligion. Thе judgе struсk down thе praсtiсе Ьесausеit indееd had thе еffесt of promoting rеligion. In thе dесision thе judgе took notiсe of law.rеviеw and othеr sсholarly artiсlеs' as wеll as tеstimony that pointеd out that thе ..thеory' not {aсt''languagе was ..onе of thе latеst stratеgiеsto dilutе еvolцtion instrцсtion еmployеdЬy аntiеvolutionists with rеligious motivations'' (Sеlmап, 1308). Singling out еvolution from all sсiеntifiс thеoriеs for spесial nеgativе trеatmеnt would havе thе еffесt of promoting thе favorеd altеrnativе to еvolution, whiсh is сrеationism. Thе distriсt appеalеd thе сasе. Thе Fifth Сirсuit Сourt of Appеalsvaсatеd thе ruling and sеnt thе саsе Ьaсk to thе Distriсt judgе for rесonsidеrationor rеtrial. Thе grounds for rеturning thе сase to thе lowеr сourt did not сonсеrn thе judgе's ruling pеr sе, Ьut rathеr a mеssy сourt rесord and missing еvidеnсе.In disсussions among thе judgе and thе two lеgal tеams, it was agгееdto rеtry thе сasе. It Ьеgan to look unpromising for thе dеfensеwhеn thе plaintiffs' lеgal tеam rесеivеd pеrmission to rеopеn disсovеry and bring in еxpеrt witnеssеs,whiсh strеngthеnеdthеir сasе Ьеforе a judgе who alrеady had rulеd in thеir favor. Thе plaintiffs' lеgal tеam was also ЬuttrеssеdЬy thе addition of somе of thе attornеys and witnеssеs who had suссеssfully dеfеatеd a sсhool Ьoard poliсy rеquiring ID in Dovеr' Pеnnsylvania; pеrhaps thе сomЬination of faсtors was suffiсiеnt to еnсouragе thе distriсt to sеttle out of сourt. Thе sеttlеmеntwas vеry favoraЬlе to thе plaintiffs, howеver, with thе distriсt agrееingnеvеr again to disсlaim еvоlution, whеthеr with tеxtbook stiсkеrs, or orally,or in any othеr form. Thе distriсt also was rеquirеd to follow thе Gеor. gia statе standards, whiсh сurrеntly rеquirе thе tеaсhing of еvolution, and to

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Amеriсап Antiеuolutioпism rеfrain from ехсising or rеdaсting matеrials On еvollltion from instrцсtional rnatеriаls.This lattеrсonsrraintwas stimulatеdЬy an еarliеrpraсtiсеin thе distriсt in whiсh thе pages on еvolution in tехtl.looks routinеly wеrе сцt out to prеvеnt studеnts from rеading thеm. Had thе СoЬЬ Сounty distriсt lost on appеal' othеr ..thеory'not faсt'' poliсiеs and disсlaimеrs would havе Ьееn еnсouгagеd, and I prеdiсt wе would havе sееn an aЬundanсе.Disсlaimеrs arе popular with sсhool Ьoards Ьесausе thеy providе thе appеaranсе that thе sсhool Ьoаrd is ..doing somеthing'' aЬout thе tеaсhing of еvolution without rеquiring сurriсulum сhange or thе Ьothеr and ехpеnsе of rеviеw and purсhasе of nеw instruсtional matеrials. Thеy satisfy a сonsеrvativе Сhristian сonstituеnсy without spеnding muсЬ timе or monеy' In Dесеmbеr 2О04, a month aftеr thе Sеlmап сasе Was triеd' a lawsuit was filеd Ьy parеnts of сhildrеn in Dovеr, Pennsylvaniа' protеsting a poliсy of its Ьoard of еduсation that would havе rеquirеd thе tеaсhing of ID and a variant of ..еvidеnсе against еvolution.,' Thе Dovеr rеsolution, whiсh latеr was insеrtеd into thе сurriсulr-rm,rеad: ..Studеnts will Ье madе awarе of gaps/proЬlеms in Darwin's Thеory and of othеr thеoriеs of еvolution inсluding, Ьut not limitеd to ID. Thе origins of Lifе is not taught.'' In NovеmЬеr 2004' amid сommunity rumors of a possiЬlе lawsuit' thе Dovеr Board of Еduсation issuеd a ..сlarifiсation'' that statеd that thе ID tехtЬook of Pапdаs апd Pеople would Ье madе availaЬlе to srudеntsas a rеfеrеnсеfor thе topiс of ID. Сonfusingly, thе сlarifiсation also statеd that tеaсhеrs wеrе not to tеaсh сrеationism or IntеlligеntDеsign. In thеir сomplaint plaintiffs arguеd that ID is a rеligious сonсеpt indistinguishaЬlе from сrеationism' and that its tеaсhing would violatе thе еstaЬlish. mеnt сlausе. Thе triаl took plaсе ovеr a siх-wееk pеriod in thе fall of 2005. Thе Disсovеry Institutе puЬliсly distanсеd itsеlf frorn thе lаwsuit, stating that ..although wе think disсussion of intеlligеntdеsign should not Ье pгohiЬitеd, wе don't think intеlligеnt dеsign should Ье rеquirеd in puЬliс sсhools'' (..Lеading Intеlligеnt Dеsign Think Tank'' 2004). Although originally a numЬеr of Fеllows of thе Disсovеry Institutе agrееd to tеstify as ехpеrt witnеssеs on Ьеhalf of thе dеfеnse, all Ьut two withdrеw from thе сasе, Ьut not until it Was too latе to add nеw ехpеrt witnеssеs. But thе two who rеmainеd, Miсhaеl Bеhе and Sсott Minniсh' wеrе thе ID proponеnts with thе Ьеst sсi. еntifiс сrеdеntials, and thus thе most qualifiеd to dеfеnd thе sсiеntifiс сrеdi_ bility of ID. Thе kеy lеgal issuе in Kitzпiller u. Douеr Arеа Sс'hool District 'vlas whеthеr thеrе was ir valid sесulаг rеason to tеасh ID. Thе oЬvious rеligious сonnotations of lD would not havе Ьееn suffiсiеnt groDnds to strikе down thе poliсy had thеrе Ьееn a valid sесulаr purposе and еffесt for tеaсhing it. Thе dеfеnsе,thеn, had to dеmonstratе that ID was a valid sсiеnсе,and that tеaсhing it as an altеrnativе to еvolution would providе studеnts with an ехсеllеnt сritiсal thinking еxеrсisе. Thе plaintiffs had to сonvinсе thе judgе that ID was пot valid sсiеnсе,and thеrеforе thе only rеason to tеaсh it was unсonstitlltionallv to Dromotе a

rеligious idеa. Thе plс dеfinitionalсharасtеr

сallsеs аnd thus tеstaЬ posеd that Ьесausе ID thегеwаs no pеdagogi At thе еnd of a long t did not mеrеly strikе dс quеstion of whеthеr ID that thе sсhool Ьoard u ligious viеw' Ьut .|udg t mеnts for and agair-rst ..in thе h that hе did so and othеr rеsourсеswh ing thе prесisе quеstion Although ID suppor сritiсizеd tЬe Kitzmille, rесtly) dесlaгingID was quirеd thе judgе to гult сould Ье а сonstitutio iudgе's dесision on wh witnеssеs for Ьoth sidе widеly usеd by sсiеntt Was that thе dеfеnsеwi Ьut thе judgе disagrе

sсhool сlassroom. Thе witnеssеs for th p е r s u а d сr h е j u d g еo f r irгеduсib1е сomplеxit1 of thе Ьlсlod сlottirrgт thеy wаntеd and mort Sсhool Board dесisior sсiеnсе-whiсh will Ь

of ID. If thе Dovеr Arеa Sс thе сountry would har gardlеss of thе ехhor tеaсhing of [D Ьy stа viеwеd as zr fornr of с сouгagе thе Ьringing diffеrеnt namе. Howеr p е a l е d а l l d t h е r е f o г еi s ID proponеnts might а ity of an ID poliсy' wi еvеr, bес:tttsеof thе l matеrial irr thе trial rе< stantially diffеrеnt out

Аmеriсап Aпtieuolutioпism on еvolution from instruсtional c Ьy an еariiеr praсtiсе in thе disbooks routinеly wеrе сut out to ..thеory,not faсt'' polial, othеr rragеd, and I prеdiсt wе would 'ular with sсhool Ьoаrds Ьесausе ..doing somеthing'' ol Ьoard is uiring сurriсulum сhangе or thе ' of nеw instruсtional matеrials. ituеnсy without spеnding muсh lсJtiC?Sewas rriеd, а lawsuit wаs ,lvania' protеstinga poliсy of its r h еt е a с h i n go f l D а n d a v a r i a n t . r е s o l u t i o nw ' hiсh lаtег was invill Ье madе awarе of gaps/probэs of еvolutioninсluding, Ьut not ught.''[n NovеmЬеr 2004' amid lе Dovеr Board of F-duсationis' tехtЬook of Pапdаs апd People fеrеnсеfor thе topiс of ID. Сon. с h с r sw е г еn o г t o t е а с h с r е a t i o n D is a rеligious сonсеpt indistin. :hingwould violаtе thе еstaЬlish.wееk pеriod in thе fall of 2005. sеlf from thе lawsuit, stating that dеsignshould not Ье prohiЬitеd, Ье rеquirеd in puЬliс sсhools'' 004). Although originally a num.еedro tеstifyas еxpеrt witnеssеs еw fгom thе сasе, Ьut not until it :s. But thе two who rеmainеd, ID proponеntswith thе Ьеst sсiiеd to dеfеnd thе sсiеntifiс сrеdi|ouer Аrеа Sсhool Distriсt was l tеaсh ID. Thе oЬvious rеligious uffiсiеntgrorrnds to strikе down urposеand еffесt for tеaсhing it. : ID was a valid sсiеnсе, and that would providе studеnts with an ,hatID was not valid sсiеnсе, and unсonstitutionallyto promotе a

rеligious idеа' Tlrе plaintiffs сolltеndеd that ID did not mееt important dеfinitional сhаrirсtеristiсsof sсiеnсе (suсh as Ьеing rеstriсtеd to natural саusеSand tlrus tеstaЬlе)and tlr:rtits faсt сlairns wеrе inсorrесt. Thеy proposеd that Ьесaцsе ID was not :l sсiеnсе and its faсt сlaims wеrе rеfutеd, thеrе was no pеdagogiсаl rеason to tеaсh it in a sсiеnсе сlass. At thе еnd of a long trial' thе plaintiffs wеrе rеwardеd with a dесision that did not mеrеly strikе down thе Dovег poliсy, Ьut that also wеighеd in on thе quеstion of wlrеthеr ID was sсiеntifiс.Thеrе wаs plеnty of еvidеnсе showing that thе sсhool board unсonstitutionally intеndеd to promotе a sесtаrian rеligious viеw, Ьut Judgе John Е. Jonеs III additionally сonsidеrеd thе argumеnts for and against thе сlаim that ID was valid sсiеnсе.Judgе Jonеs wrotе ..ir-r that hе did so thе hopе that it may prеvеnt thе oЬvious wastе of judiсial аrrdotlrеr rеsourсеswhiсh would Ье oссasionеd Ьy a suЬsеquеnttriаl involving thе prесisе quеstion whiсh is Ьеforе us,, (Kitzmiller,7З5). Although ID supportеrs from thе Disсovеry Institutе (Dе.!7olfеt al. 2006) сritiсizеd the Kitzшiller dесision as unnесеssarily (and in thеir viеw, inсorrесtly)dесlaring ID was not a valid sсiеnсе,thе lеgal thеoriеs of Ьoth sidеs rеquirеd thе judgе to гulе on prесisеly this pоint: if ID was valid sсiеnсе,thеrе сould bе a сonstitutionally admissiЬlе sесular rеason for tеaсhing it. Thе judgе'sdесision on whеthеr ID was sсiеnсе wаs rеlativеly straightforward: witnеssеs for Ьoth sidеs tеstifiеd that Ьy thе standard dеfinition of sсiеnсе as widеly usеd Ьy sсiеntiststoday, ID did not qualify as sсiеnсе.Thе diffеrеnсе was that thе dеfеnsеwantеd to сhаrngеthе dеfinition of sсiеnсеto inсludе ID, Ьut thе jirdgе disаgrееd thаr suсl.ra dесision should bе mаdе in thе high_ sсhool сlassroom. Thе witnеssеs for thе dеfеnsе did not farе any Ьеttеr in thеir аttеmpt to pеrsuadеthе judgе of thе validity of thе сlaims of ID (suсh as thе supposеd irrеduсiЬlе сomplехity of thе Ьaсtеrial flagеllum and thе unеvolvеaЬility of thе Ьlood сlotting mесhаnism). In thе еnd, thе plaintiffs got еvегything thеy wantеd and morе: a dесision not only striking down thе Dоvеr Arеa Sсhool Board dесision, but a dесision еvaluating ID as not qr-ralifyingas sсiеnсе-whiсh will Ье сitеd in any futurе attеmpt to rеquirе thе tеaсhing of ID. If thе Dovеr Arеa Sсhool Board lrad Won thе сasе' sсhool distriсts around thе сountry woцld havе Ьееn еrrсouragеdto imposе similar ID poliсiеs, re. gагdlеssof thе ехhortations of thе Disсovеry Institutе not to rеquirе thе tеaсhing of ID by statutе. Intе[ligеnt Dеsign is widеly-and aссuratеlyviеwеd as a form of сrеаtionism, and a lеgally suссеssfulpoliсy would еnсouragе thе Ьringing of сrеationism into thе сlassroom, alЬеit undеr a diffеrеnt namе. Нowеvеr strong a dесision, tЬe Kitzlпiller ruling Was not appеalеdand tlrеrеfoгеis prесеdеntonly in thе Мiddlе Distriсt of Pеnnsylvania. ID proponеnts might attеmpt to find anothеr vеnuе in whiсh to tеst thе lеgality of an ID poliсy, with a diffеrеnt sеt of faсts and а diffеrеnt judgе. Howеvеr, Ьесausе of thе Ьrеаdth of thе Kitzmillеr dесision аnd thе wеalth of matеrialin thе triаl rесord' it is douЬtful that anothег trial would havе a suЬstantialiydiffеrеnt outсoп1е.

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АmеricапАntiеuolutiсlпism Thе most popular antiеvolutionist stratеgy in thе futurе, though' will Ье dirесtivеs from sсhool Ьoards or statе Ьoards of еduсation for tеaсhеrs to ..balanсе'' еvolution with thе tеaсhing of ..еvidеnсе against еvolution.'' It is not сlеar whеthеr judgеs will Ье pегsuadеd,as Was Judgе Сoopеr in thе Sеlmап сasе, that ..еvidеnсеagainst еvolution'' is a сodе phrasе for сrеationism; this rеquirеs an apprесiation of thе history of thе сrеationism/еvolution сontrovеrsy. Bесausе сrеationists Ьеliеvе and loudly proсlaim that thеrе arе only two altеrnativеs, сrеationism and еvolution, thеy еnсouragе tеaсhеrs to tеaсh that еvolution сannot еxplain thе divеrsity of living things. \й/ithеvolution out of thе piсturе, thеy Ьеliеvе that studеnts will сonсludе that living things wеrе spесially сrеatеd. During 2008 thеrе was a flurry of ..Aсadеmiс Frееdom Aсts'' introduсеd into sеvеral statе lеgislaturеs(Florida, Мissouri, AlaЬama' Мiсhigan' and South Сarolina) that would pеrmit and еnсouragе tеaсhеrs to tеaсh that еvolution is an еrronеous idеa. Boilеrplatе for suсh ..Aсadеmiс Frееdom Aсts'' is providеd Ьy thе Disсovеry Institutе on a wеЬsitе (Aсadеmiс Frееdom Pеtition 2008). Rathеr t'Ьan direсtizg tеaсhеrs to tеaсh thе tехtЬook vеrsion of еvolution and thеn сritiсizе this viеw, suсh Ьills prosсribе aсtions Ьy sсhool distriсts that might pеnalizе thе tеaсhеr for doing so. Rathеr than ovеrtly proposing that сrеationism bе taught, thе foсusor misdirесtion-is on thе aсadеmiс frееdom of tеaсhеrs to tеaсh ..strеngths and wеaknеssеs'' of еvolution (as in thе South Сarolina Ьill, sB 1386 ..full rangе of [..Antiеvolution Lеgislation in South Сarolina'' 2008]) or thе sсiеntifiс viеws'' (as in Florida's SB 2692 f.,Аntiеvolution Bills Dеad in Florida'' 2008]). But what suсh Ьills proposе is to protесt tеaсhеrsfrom сonsеquеnсеs of violating thе First Amеndmеnt. lй/hеthеr suсh ..gеt оut of jail frее'' сards would Ье сonstitutional rеmains to Ье tеstеd, Ьut at thе timе o{ this writing (July 2008) nonе of thеsе Ьills havе pаssеd. .!Иill judgеs always strike down suсh poliсiеs? Lеgal еxpеrts notеd that Ьy thе end of thе first tеrm of Prеsidеnt Gеorgе \W.Bush' ..all of thе 13 сirсuits will havе a majority of RеpuЬliсan judgеs'' (Сarp еt aL.2О04,25). As Bush's sесond tеrm сomеs to an еnd, ..PrеsidеntBush has namеd 294 judgеs to thе fеdеral сourts' giving RеpuЬliсan appointееsa solid majority of thе sеats,inсluding a 6О"Ь.to-40oЬ edge ovеr Dеmoсrats on thе influеntial U.S. appеals сourts'' (Savagе2008' A11). An analysis of dесisions of judgеs appointеd Ьy thе last еight prеsidеntsshows that Prеsidеnt Bush's first-tеrmappointееsarе partiсularly сonsеrvativе in сasеs involving сivil liЬеrtiеs' among whiсh issuеs of sеparation of сhurсh and statе arе found. ..Only 28 pеrсеnt of thе Bush сohort votеd on thе liЬеral sidе of issuеs pеrtaining to Bill of Rights and сivil rights mattеrs, thus giving thе prеsidеnt thе lowеst sсorе of any modеrn сhiеf ехесutivе,' (Сarp et a|,20О4,26).It is not unfair to сonсludе that thе lеgal сlimatе favoring thе еstаЬlishmеnt сlausе ovеr thе frее еxеrсisе сlausе in еduсаtional affairs has wеakеnеd. It may Ье that thе lеgal safеguards that havе until now disсouragеd thе inсlusion of various forms of сrеationism in thе puЬliс sсhool sсiеnсе сlassroom will bе morе diffiсult to mustеr by thе sсiеntists and tеaсhеrs and parеnts who support еvolution еduсation.

AсKNoWLЕDG

I t h а n k G l е n n B г а n с ha n г o г h е m а n u s с r i p г .w h i с h

NoтЕs

1. Сrеation sсiеnсеhad of Judgе !Иilliam Ovеrtoл only rr,voaltеrnativеs:еvo сrеation sсiеnсе advoсatе еvidеnсе for сrеationism; altеrnativе of сrеation Ьy 2. In kееping with thе divirrе асtion in thе rеаlrт fi nе-tuning argumеntsaг( s с t l p еo f t h i s d i s с u s s i o nt a n d с o n t l n . JS t е n g е r2 0 0 3 . Е х а m p l е si n с | u d еD Hunrеr 200l; andWikег 4. [n truth, origin sсiе a s t r o n o m y ' g е o l o g y 'Ь i o I г h е . э l o g yt:h е l l i g h a n g .т t thе origin of humаns.

в|BLIoGRAPHY

A с a d е m i с F r е е d o mP е t i t .асadеmiсfгееdоmр Altеrs, B. J., arrd С. Е. Nt еduсation. Еuolutior , \ n t i е v o l u t i o nb i l l s d е . l di Мay 3. http://www. _Ьi l ls_dеаd_in_fl_s Antiеvoiution lеgislation Еduсation, Мay 15. 5 3 5_аntiеvolution_l Аntiеvolution standards: Е d u с a t i o n ,N o v е m Ь _аntiеvolution_stаnd Bеhе,М. |996, po'*|n.'

Nеw York: Frее Prеs 2000. [untitlеda .org/сgi/еlеttеrsl 288l' 2ОО7. Thе F.dgс, Nеw Yoгk: l-rееPrеs Blасkstonе, N. W. 1997. Boх: Тhс Bioсhсmi,, no.4:445-447. Сairns-Smith, A. G. 1985 Univеrsity Prеss.

Аmeriсап Аntieuolutionism in thе futllrе, though, will Ье i of еduсation for tеaсhеrs to .еvidеnсеagainst еvolution.'' d, as was Judgе Coopеr in thе s a сodеphrаsеfor сrеationism; of thе сrеationism/еvolution loudly proсlaim that thеrе arе эn, thеy еnсouragе tеaсhеrs to .With еvoluty of living things. lents will сonсludе that living ..Aсadеmiс еrе Was a flurry of е g i s l а t u r е(sF l o r i d а ' M i s s o u г i ' t would pеrmit and еnсouragе ous idеa. Boilеrplatе for suсh Disсovеry Institutе on a wеЬhеr than directiпg tеaсhеrs to еn сritiсizе this viеw, suсh Ьills ht pеnalizеthе tеaсhеr for doltionism Ье tаught, thе foсus..strеngths of tеaсhеrsto tеaсh iouth Сarolina Ьill, SB 1386 ..full rangе of l'' 2008]) or thе [..AntiеvоlutionBills Dеad in is to protесt tеaсhеrs from сon.DИhеthеr ..gеt out of jail suсh гo Ье tеstеd, Ьut at thе timе of rе passеd. эs?Lеgal ехpеrts notеd that Ьy . . a l lo f t h е l З с i r с u i t s W. Bush, ) a r pе t a | . 2 0 0 4 , 2 5 ) . A s B u s h ' s h has namеd 294 judges to thе l s o l i d m a j o r i t yo f t h е s е a t s ,i n оn thе influеntial U.S. appеals есisionsof iudgеs appointеd Ьy Bush's first-tеrm appointееS arе сivii liЬеrtiеs' among whiсЬ is. .ound...only 28 pеrсеnt of thе uеs pеrtaining to Bill of Rights : s i d е n tt h е l o w е s г s с o r е o f а n y 26). It is not unfair to сonсludе L е n tс l a u s еo v е r t h е f r е е е х е r с i s е . It may Ье thаt thе lеgal safее inсlusion of various forms of 'sroom will Ье morе diffiсult to parеnts who support еvolution

AсKNoWLЕDGMЕNтs .!Иеslеy I thаnk Glеnn Branсh and ЕlsЬеrry for hеlpful сommеnts on and сorrесtions to thе manusсript,whiсh suЬstantiallyimproved it.

NoтЕs l. Сrеаtion sсiеnсе had еarliеr Ьееn typifiеd Ьy a ..соntrivеd dualism,'' in the words of Judgе !Иilliam Ovеrton in МсLеап u, Arkапsаs, whiсh assumеd that thеrе wеrе only two altеrnаtivеs:еvolution or spесial сrеation. With only twо altеrnativеs, сrеation sсiеnсе аdvoсatеs arguеd that еvidеnсе against еvolutiot-twas ipso faсto еvidеnсеfor сrеаtionism; ID likеwisе rеliеs on disproving еvolution to Support thе altеrnаtivеof сrеation Ьy an intеlligеnt agеnt. 2. In kееping with thе Ьig-tеnt stratеgy' ID also wеlсomеs thosе who sее rоom fоr divinе aсtion in thе rеalm of сosmology; disсussionsof thе anthropiс prinсiplе and finе-tuningаrgumеntsаrе not unсommon in thеir puЬliсations. It is Ьеyond thе sсopеo{ this disсussionto сorrsidеrthеsе;sее Мanson 2003 fсlr rеprеsеntationpro аnd сon and Stеngеr 20О4 for an ехtеndеd argumеnt аgаir-rst. 3. Ехamplеs inсludе DеmЬski 1998Ь, 1999; Johnson 2002; Мorеland 1'994; Huntеr 2001; and.Wikеr 2002. 4. In truth, origin sсiеnсеrеduсеsto thosе issuеsin thе historiсal sсiеnсеsof astronomy' gеology, Ьiology, and anthropology that havе impliсations for Сhristian thеology:thе Ьig Ьаng, thе origin оf lifе, thе оrigin сlf thе ..kinds'' of aпimals, and thе origin of humans.

в|вLIoGRAPHY Aсadеmiс }.rееdomPеtition. 2008. Disсovеry Institutе.http://www .aсadеmiсfrееdompеtition.сom/frееdom.php (ассеssеdМaу 22, 2008|, Altеrs,B. J., and С. Е. Nеlson. 2002. Pеrspесtivе:Tеaсhing еvolution in highеr е d u с a t i о n .Е u o l u t i с . l 5 п6 , n o . ] 0 : l 8 9 1 - 1 9 0 l . АntiеvolutionЬills dеаd in Florida. 2008. Nаtional Сеntеr fсlr SсiеnсеЕduсation, May З. http://www.nсsеwеЬ.org/rеsourсеs/nеws/2008lFLl739'antiеvolutiсln (aссеssеdМay 23, 2008). _Ьills_dеad_in_fl_5_3_2008.аsp Antiеvolutionlеgislationin South Сarolina. 2008. National Сеntеr for Sсiеnсе Еduсation, Мay 1 5. http://www.nсsеwеЬ'org/rеsourсеs/nеws/200 8/Sс/ (aссеssеdMay 22, 2008). 53'5_аntievolution_lеgislation_in_s_5_15_2008.аsp Antiеvolution standards adоptеd in Kansas. 2005. Nationаl Сеntеr for Sсiеnсе 5 /KS/3 ]6 ЕJuс аtiоn. Nоч<mЬеr 17. http://ъ.ъъ..n;sсrrеЬ.отg/теsоuт;еs/nеrчr/]00 (aссеssеd 2008). Мay 15' 1_10_2005.asp _аntiеvolution-standards_adoptе_1 Bеhе,М. 1996. Dаrшiп's Blасk Boх: Thе Biochеmiсаl Сhаllепge to Еuolиtюп. Nеw York: Frее Prеss. 2000. [untitlеd artiсlе]. Опliпe Sсiепсе Маgаzinе, http://www.sсiеnсеmag 5467 1813#165(aссеssеdJuly 7, 2000). .org/сgi/еlеttеrsl288l 2007. Thе Еdgе of Еuolutklп: Thе Sеаrсh for tЬе Limits of Dаrшiпism. Nеw York: Frее Prеss. Blaсkstonе,N. !и. 1997. Argumеntum ad ignorantiam: A rеviеw of Dаrluiп's Blасk Boх: Thе BioсhеmiсаI СhаIlепgе tсl Еuolutklп. Quаrtеrlу Rеuiеt,tlof Biologу 72, no. 4: 445-447. Сairns-Smith, A. G. 1 985 . Sеuеп Сlttеs to thе Оrigiп of Lifе. СamЬridgе: Сambridgе Univеrsity Prеss.

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Аmer i с ап Апtiеt, o lиt iс.lпtsrп Сrrrp, R. A., K. L. N1anning,and R. Stidharт.2004. Тhе dесision-mаkingЬеhavior of Gес-lгgеW. BLrsh.sjudiсial арроiIrtn.rеnts, 88, nсr. 1: 20-28. .|udiссtturе Саvaliеr-SmitЬ,т. |997. Thе Ьlirrr.] Ьioсhеmist.Тrеltr]sin Есolсlgуапd Еuolиtioп 12: 162_|6З. Сoynе, .|.^. 1996. God in thе dеtaiIs.Nаturе 383:227-228. Сrеation musеum unехpесtеd sllссеss. 20О8. Floridа tsаptist Witпеss, Aрril 17. (:rссеssеd http://www.floridaЬaptistwitlrеss.сom/8688.artiсlс Маy 15, 2008). Сur-rningham,D, L. 1999. Сrеаtiсlnisttоrnаdo rips еvolLrtiоrrout of Kаnsаs sсlеnсе standards. Rеprlrtsoi thе Nаtionаl Сеntеr fоr SсiеnсеЕduсаtitlп l9, no. 4: 10 - 1 4 . .!7., Davis, P. and D. Н. Kеnyon . 1993. Оf Pапdаs апd Pесlplе.2nd еd.-Dallas,TХ: Haughton. DеmЬski, W. 199.5.What еvеry thеologian should knоrv аЬout сrеatiоn, еvolution' and dеsign. Сeпtеr for lntеrdisсipliпаrу Studiеs Trаltsасtioпs З: 1_8. 1998a. Thе Dс'sigп Iпfеrепсе:Еliпtinаtiпg Сhсlпсе thrсlugh Smаll Probаbilitiеs, Nеw York: СamЬridgе Univеrsitt. Ргеss. -l еd. 1998Ь. Мerе Сreаtioп: Sсiепсе, Fаith апd lntеlligепt Dеsigll. Dсlwnеrs Grovе, Il-: Ir-rtеrVarsityPrеss. 1'999, Iпtеlligепt Dеsigп: Tbe Bridgе bеttuеепSсiепсе апd Tbеoklgу' Downеrs Gr
200s).

Еvе, R., and F-.B. H:rrrold. |991.Thе (-'rеаtkпist Мouепlеnt in Мсldеrп Аlпеrrcа. Boston: Twa1'nе Pr'rblishеrs. Еvolution rеturns to Кansаs. 2007. Natiсlnal Cеrrtеr.for SсiеnсеЕduсаtion, FеЬruary 14. http:/hr.ww.nсsеwеb.сlrg/rеsouгсеs/t"tеwsl20О7lKSl286_еvolutiсlп-rегurns_to _kansas_2_14_2007.asp(aссеssеdMay 15, 2008). Ехposing thе flaws of thе Kansas sсiсnсе standards.2006. Natiоnal Сеntеr for SсiеnсеЕduсation, July 19. httр:/iwww.nсsеWеЬ.Org/rеsourсеs/nеws/2006lKSl 172-ехposing_tlrе'flaws_of_thе-kans7_19_2006.zts;l(aссеssеdМay 1.5,2008). Fitеlson, B., С. Stерhеrrs'and Е' SсlЬеr. l999. Ноw псlt to dеtесtdеsign:A rеviеw сlf \William A. DеmЬski's TЬе Dasign lпfеrепсе. PhiIсlst-lpЬуof Sсiепсс 66: 472488' Forrеst, B., and P. Gross. 2ОО4' Сrсiltiгlпism'sTrojап Llorsе. Nеw York: Oхford Univеrsity Prеss. Gilсhrist, G.w.1997. Thе еlusivе sсiеntifiсЬasis of InгеlligеntDеsign Thеory. Rеports of thе Nаtir.lnаl Сепtеr iсlr Sсiепсе Еduсаtitltt 17, no. 3: 14_1.5. Gishliсk' A. D. 200.]. Iсons of еvсllution?Why muсh of rvlrаtjonathan Wеlls и'ritеs аbout еvolution is wrong. Nаtionаl Сеntеr for SсiеnсеЕduсatitlll. lrttp://www (aссеssеd.Januar.yl.5' 2005)' .nсsеwеЬ.org/iсons/ 2004. Еvolutionarу Paths tсl irrеduсiЬly сomplсх systеms.ln М. Yоurrg and T. Еdis, еds., V(/Йylпtеlligеnt Dеsigп Fаils: А Sciепtifiс Сritiquе of thc Nеш Сrеаtioпism,.58-7l . Nеw Brunsп,iсk, Nl: Rr.rtgеrsUrrivеrsityPrеss. judgе.Sсiспti|iсАmеriсап,Iu|у: Gсluld, S. J. 1992.Irтpеaсhing a sеlf-а1-lpointсd I 1U-121.

H t t n t е r ,С . G . 2 0 0 1 . D . l Rаpids, N{I:Brlrztls сlf Еuolutitпl. 200 1с:r>пs Produсtions. Institutе for Сrеation Rr mеаning. lСR llпpс .htm. P. Е. 1991 ' D"' Jсllrrrsor-r. 1,997.Dеiеаtin1 IntеrVarsity Pгеss. 2ОО2. Тhе Righ Grovе' IL: IntеrVаr Kеrrt Hоvind sеntеnсеd .[:-rnuаry24. httр://

_sсntеnсеd_to_tеtKr-rshinеr,J. M. 2000. B Larson' Е. l.2ОО3. Тriа Еuolutioп. Зrd сd. . I,е:rdingIntеlligеntDеsi for it to Ье ц.ithdra sсriрts/viеwDB/inс %'20and9,Ь2ONеw l'еrnеr,l,. S. 2000. Gor; $7ashington,DС: T [,ynсh, J. 2002. Сrеаtitlt Тhoеmmеs Prеss. М:lnsоn, N. A., еd.200 Sсiепсе. Lonс]on:R Ntatzkе, N. 2004. Iсоn r. http://www.tаlkor МсMurtriе, B. 200l . Dl D е с е m Ь е r2 1 ' 8 . Millеr, K. B., еd.200.i. Ееrdmаns. ]vlillеr, K. R. 1999' Flnс \,Iсlrеl:rnd'J. P., еd' l99 IntеrVarsity Prеss. N{оrris, Н. R. 1980. Тhr N t t п r b е r s ,R . | 9 9 2 . Т h е orr, H. A. 1996. Dаrrv TЬе pеndulum slvillgsrl August 2. httр://w swings-in kaпsas Pеnnосk, R. T. 1999. Т( СаmЬridgе, МA: lv еd.2О01. IпtсI МIT Prеss. 2003. Crеation Hltmап Cеttеtiсs 4: Rosеn, l,. 2003a. Dагwi ..lr.rtеlligеnt Dеsigr 2003Ь. RosеviI tеасhеsDагwrп llrr . | L r l у3 .

Amеriсап Аntiеuolиtioпism 1. Thе dесision.makingЬеhavior d i с а t u r е8 8 , n o . 1 : 2 0 _ 2 8 . .епds itl F'сologу апd Еuolutiсlп

: 2 2 7 - 2 2'V/itnеss' 8. April 17. dаBаptist Маy 1.5,2008). rtiсlе(aссеssеd s еvolutionout of Кansаs sсlеnсе , SсiепсеЕduсаtioп 19, no. 4: .2nd еd. Dallas, TХ: s апtl Pесlple l know aЬout сfеation' еvolution, i,еsTrаnsасtiсlпs3: 1_8. 1 Сhапсе thrсlttghSmаll ity Prеss. апd IпtеlligеlttDеsigtl. Downеrs uееnSсiепсеапd The olсlgу. )spесts'pitfalls, and rеality сhесk 10.27.Disсiplinсd rmеnts/2002. 2О06. Trаipsiпg illto Еuolutiсlп: D есisirп. Sеattlе:Disсovеry с inquiry, mispеrсеivеd.Аmеriсап еory' еvolutionary сomputatron' on.', NovеmЬег 23. http://www еmЬski.pdf(ассеssеdJanuary 1.5, ! МtluсlпсttIiп |tIl'dсrп Аmсriса. ttегfor SсiеnсеЕduсаtion, FеЬruary |2007 lKSl 28 6 _еvolutiоn-rеturns-to

2008).

ds. 2006. National Сеr-rtеrfor wеЬ.org/rеsоurсеs/nеws/2006/KS/ _2006.asр(aссеssеdMay 15, 2008). )w not to dеtесt dеsign: A rеviеlv of Philostlphу of Sсiепсе 66: 472488. ,ojаll Hоrsе. Nеw York: oхford i of Intеlligеnt Dеsign Thеоry. Е d u с а t k l п1 7 , n o . 3 : 1 4 - 1 5 . .Wеlls writеs luсh of what Jonathan or SсiеnсеЕduсation. http://www

00s).

сomplех systеms. In I\4. Young and А Sсiепtifiс Сritiqие of tbе Nеtu l.utgеrsUnivеrsity Prеss. udge' Sсiепtifiс Аmеricап, lu|у:

Нuntеr, с. G. 2001' Dаrшiп's God: Еuсllutioп апd thе Problеm of Еuil. Grand Rrrpids,МI: Bгazos Prеss. Icoпs of Еuolutioп' 2ОО2,B. Boorujy, diгесtоr. DVD. 75 minutеs. N.p.: Randolph Produсtions. Institutеfor Сrеation Rеsеarсh (IсR)' 1987. Thе Suprеmе Сourt dесision and iтs mеaning. lСR lmpасt no. l70 (August).http://www.iсr.org/puЬs/irnp/imp-170 .htm. Johnson' P. Е. 1991. Dаrulin tlп Тriаl..Washington'DС: Rеgnегy Gatеway. 1997. Dеfеаtiпg Dаrшiпism bу Оpепiпg Мiпds. Downетs Grovе, IL: Ir.rtеrVarsityPrеss. 2О02. Thе Right Quеstil.ltts Trиth, Меапiпg апd Publiс Dеbаtе. Downеrs Grоvе, IL: IntегVarsityPrеss. Kеnt Hovind sеntеnсеdto 10 yеаrs.2007. Nаtional Сеntеr for SсiеnсеЕduсation, January 24. http://r,vww.nсsеwеЬ.org/rеsourсеs/nеwsl2ОО7lFLl789_kеnt_hovind _sеntеnсеd_to'tел у 1_24 _2007.asp (aссеssеd Мaу 22, 2008|. Kushinеr,J. М. 2000. Bеrkсlеy'sradiсa]. Toцсhstoпе 15, nо. 5: 40. Larson' Е. J. 200з. Triаl апd Еrror: Thе Аmеricап Ссlпtrсluеrsуouеr Сrеаtiсlп апd Еuсllutioп,3rd еd. Nеw York: Oхfоrd Univеrsity Prеss. l,еadingIntеlligеntDеsign think tаnk саlls Dovеr еvоlution poliсy ..misguidеd,''сalls for it to Ье withdrаwn ,2004, Disсovегy Institutе.http://wrvw.disсovеry.org/ sсripts/viеwDB/indех.php ?ссlmmand=viеw&program=СSС%20-%20Viеws ,,/"20and,,/"2ОNеws &id=2 3 4 -l (aссеssеd DесеmЬеr \ 4, 2004|, I-еrnеr,L. s. 2000. Good Sсiепсе, Bаd Sсiепсе: Tеасhing Еuollltioп iп thе Stаtеs. .Wаshington, DС: Thсlmas B. Fordhаrn Foundatiсln. Lynсh' J. 20О2. Сrеаtirпism апd Sсriptиrаl Gеologу, 1817-18.\7, London: Bristol Thoеmmеs Prеss. Мansсln, N. А.' еd. 2ООЗ. God апd Dеsigп: TЬе Tеlеologiсаl Аrgumеnt апd Мodеrп Sсiепсе.London: Routlеdgе. Matzkе, N. 2004. lсon of oЬfusсаtion. Talkorigins Arсhivе, updatеd January 23,2004. http://www.talkorigins.оrg/faqs/wеl ls/iсonoЬ.html(aссеssеdJаnuary 14' 2005 ). МсMurtriе, B. 2001. Dаrwin undеr attaсk. Сbroпiсlе of Highеr F'duсаtioп' D е с е m b е r2 1 , 8 . Мillеr, K. B', еd. 200З. Pеrspесtiuеsсlп ап Еu
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Americап Апtieuolutioпism \|slit.Sdсrаmeпto Bее, SеptеmЬеr еory' аnd еvolution. Еuolutil>п 56, ', AR: Nlastеrbooks. rshlеgaсy:Thе prеsidеnt'ssuссеss .hеfеdеralЬеnсh a dесidеd GoP аy. Rсprlrls tlf thе Nаtioltаl Сепter in thе Unitеd States.Аnпuаl ..thеistlс sсholаrshiр,''irnd N,ltkпаI Сеntеr for Sсiепсе 149 зwеЬ.org/rеsourсеs/artiсlеs/6 Rеports of thе Nаtiсlпаl Сеntеr for эduсtioп..!7еstpоrt,СT: Grееnwоod i s m :С h а n g е sа n d с t ' n t i n u i l i е s . lеsign in sсiеnсесlassrooms. с п с e s1 О 4 ( S u p p l .\ ) : 8 6 6 9 - 8 6 7 6 . :al аnalysisof IntеlligеntDesign in -2.98. "itiquе of Iпtеlligепt Dеsigп Thесlrу. y rеirsоning.lntеrпаtkпаl J ou'rnаl s? In М. Young аnd T. Еdis' еds., itiquс о[ thс Nсш Сrсаtiсlпism' vеrsityPrеss. 1984.Thе Муstсrl, of l-ifе's origiп: hilosophiсalLibrary. сation of possiЬlеroutеs of | 'B i с l l с l g2у0 3 : 1 1 1 _ 1 1 6 . irесtor.DVD. 67 minutеs. Lir Нсlш Did lt Gсt Hеrе? 8y 7atсhtowеrBiblе and Traсt Soсiеty A сritiquе of Willirrn-r сlсolatеs: )rigiпsArсhivе (updatеd Aрril 23, qs/nfl/(aссеssеdJanuary 24, 200 5I. ЭеnеsisFlood: T.he Bibliсаl Rесord NJ: PrеsЬytеriаnаnd Rеformеd. саmе Hеdoпisfs.Downеrs Grovе, IL: r'antаgеsof thеft оvеr toil: TЬе dеsign э g уо п d P h i l r l s o p h l | 6 : 7 7 1 - 7 2 4 . ,епtDеsigп Fаils: А Sсiепtifiс nsrviсkN . J : R u t g е r sU n i v е r s i t y

сoURт oP|N|oNs с|тЕD Dапiеlu. Wаtеrs.U.S. Сourt of Appеals,Siхth Сirсuit.515 F.2d 485 (1975). Еdшаrdsu. AgиiIIаrd.482U.S. 578 {,1987I. Е p p е r s с luп. А r k а п s а s , 3 9 3U . s . 9 7 ( | 9 6 8 \ , Kitzmil!еru. Douеr Аrеа SсhoolDistriсt'400 F. Supp.2d 707 (М.D. Pa. 2005). МсLеапu. ArkапsаsBoаrd of Еduсаtion.529F. Supp.(Е.D.Ark. 1982) Sеlmапu. Сobb СoltlttуSсhoсllDistriсt.390F' Supp.2d (N.D. Gа. 2005).

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This Ьook, puЬlis .!7illiams, is onе o] thоugh nеo-Darwi lishеd paradigm сommittеd to thе t сious imprеssions. thе есologist Vеro Soсiаl Behаuiсlur grouр ovеr thе inс possiЬility of grou ought to alwаys pl vidual еffесtsand l In making his сu groundЬrеaking p (1964a,1964Ь)ш , (ants, Ьееs, and w known as kirr sе сhanсеs by raising produсtion. Anothеr topiс a progrеss' thеn mu .!7il Rusе 1996). progrеss' pointing ity) arе oftеn vеr tаkеs dеvеlopmеn сrеdiЬly сomplех plех is Ьеttеr.A jеt propеllеr еnginе, lattеr. Thе main thrus and genеrally suff sсorn Was rеsеrvе lесtion. С. H. Wa similation, whеге .\Х/illiams hас fliеs.

Аdаptаtion аnd Nаturаl Selection (Gеorgе C. Williams) This Ьook, puЬlishеd iл 1966 Ьy thе Amеriсan iсhtlryologist Gеoгgе С' Williams, is onе of thе grеat dеЬunking works irr thе history of sсiеnсе.Although nеo.Darwinism, or thе syrrthеtiсthеory of еvolution, was thе еstaЬlishеd paradigm in еvolutionary studiеs, Williams (who was dееply сommittеd to thе tlrеory itsеlf) fеlt that it was infесtеd Ьy a numЬеr of fallaсior.rsimprеssiсlns.Ivlost signifiсant of thеsе Was the Ьеliеf, promulgatеd Ьy .Wynnе-Еdrvards thе есologisr Vеro С. in Апimаl Dispеrsiotl in Rеlаtiotz to Soсiаl Bеhаuioцr (|962\, гhat stlrnеtimеsnaturаl sеlесtion сan favor thе group ovеr thе irrdrvidual.Although hе did not want to dеny thе outright possiЬilityof group sеlесtion,Y/illiams fеlt that on gгounds of simpliсity onе ought to always prеfеr thе hypothеsis that group еffесtsаrе сausеd Ьy individual еffесtsаnd tlrirtsеlесtionthегеforеrnust Ьеnefitfirst thе individual' In making his сasе, Wiiliarns was onе of thе first tO makе rеfеrеnсеto thе groundЬrеaking papеrs of thе tlrеn-graduatе studеnt \Х/illiam Нamilton (I964a, 1964ь), r,vhohad shown how thе stеrility of hymеnoptеran rvorkеrs (ants,Ьееs, and w.asps)сould Ье ехplainеd as a rеsult of what has Ьесomе known as kin sеlесtion. Thе workеrs аre improvillg thеiг rеproduсtivе сhanсеsЬy raising fеrtilе rеlativеsinstеad of putting еfforts into thеir owt] rеproduсtion. Anothеr topiс attaсkеd with rеlish Ьy \Х/illiamswаs that of еvolшtionary progrеss'thеn mrrсh favorеd Ьy pеoplе likе Julian Huxlеy (7942; sее аlso Rusе 1996). \Williams was withеring in his сritiquе of various notions of progrеss,pointing out that populaг сritеria of improvеmеnt (likе сomplех. itv) aге oftеn vеr1' rrrislеading.Аp:rгt from thе faсt tlrat gеnеrally lro onе takеsdеvеlopmеntinto aссount (thе livеr flukеs rhаt affесt shееp hаvе an inсrеdiЬlyсomplех lifе history), it is Ьy no mеans oЬvi
40З

Аgаssiz fеrеnсеs аЬout thе irradеquaсy of sеlесtion as suсh arе simplу not wеll tаkеn. For him, and for his пrany еnthtlsiastiс rеzrdеrs' a strippеd_down' purе Darwinism is not only aеsthеtiсally morе attraсtivе' it is sсiеntiIiсally supеriora point lost on thе philosophy h,ppy

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BlBLIoGRAPнY Нamilton, W. D. 1964zr.Thе gеnеtiсalеvоluti
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Louis Agasstzwаs а mаs spесimеn,Сусlopomа s1 d r е a n ri n w h i с h h е s а w t thаt hе had mаdе from r с o r r е s p o n d е dе х a с т l уl.t 20-21.

Agassiz,JеanLоuis Rоdоlphe$8a7_t873\ Born in Switzеrland in 1807, l,ouis Agassiz as a Ьoy Was a kееn naturalist.Hе studiеd Ьiology at sеvеralGеrman univеrsitiеs,еarning an advanсеd dеgrееin narural history \n 1829. Hе soon еarnеd a rеputatioll as a brilliant rеsеarсhеr' thanks to Ьooks dеsсriЬing spесiеs of fislr' living and fossil' and to his сarеful studiеsof Alpinе glaсiеrs(Agassiz 1833_1843' 1840) (sееfigurе).Bеginningin 1837 hе аssеmЬlеdеvidеnсе for а surprisirrgnеw thеory aЬout an Iсе Agе, whеn a thiсk lаyеr of iсе had ссrvеrеdnorthеrn Еuropе. Aftеr moving to thе Unitеd Statesin 1846,Ьe Ьесamеonе of Amеriсa's lеading sсiеntists,founding thе Мusеurn of Сomparativе Zoology at Harvard in 1859. A сharismatiс lесturеr' Agassiz сhaгmеd thе puЬliс as wеll as his studеnts with dеsсriptions of rесеnt disсovеriеs in еmЬryсllogy' palеontology, and anatomy. Likе Riсhаrd Owеn in Lоndоn, Agassiz еmphasizеdthе pattеrn of rеsеmЬlanсеsсallеd hornolоgv. Althouglr it had long Ьееn known that tlrе struсturе of an animal's organs is геlatеdto thеir funсtion, not until thе ninеtееnth сеntury did hiologists сonfront thе faсt that divеrsе сrеaturеssееm to bе modifiсаtions of а сommon Ьluеprint or typе. VеrtеЬratеsarе onе sllсh typе' Ьесausеthе samе layout of Ьonеs and othег organs сan Ье traсеd in a fish, a frog, a Ьat, and a humаn. Agassiz imprеssеdhis audiеnсеswith unfamiliar ехamplеs of tlrе samе prinсiplе:thаt Ьееs,spidеrs,and loЬstеrsarе 2rlso honrologous to otlе anothеr' аs arе oсtopusеs,snails, and сlams, or stirrfish, jеllyfish, sеa urсhins, and сorаl polyps. F.ollоwing Gеorgеs Сuviеr, hе сallеd thеsеfour gгoups vеrtеЬratеs,ilrtiсLllatеs,mollusks, and radiаtеs.In his Еssay

oп Сlаssifiсаtioп (|8, aсross еmЬryoniс forш ..Onе ! thе ехistеnсе of blanсеs Ьеforе hе сгеa .sИilliam Palеy, whosе makеr or еnginееr Wh puгposе. Agassiz.sGod еral variations on a fеv Agassiz аrguеdthat ation and саnnot сhar jесtеd thе Ьibliсal sto сhallеngеd whеn hе еn doеs him no сrеdit' Не

an opinion wеlсomеd Darwin's oп thе О' Pt prеtation of narr.rrе. win arguеd that homо сommon anсеstoг,wh n а t ц r a l s е l е с t i o n .B е f a с с е P r е dе v o l u r i o n ,i f t o B r a z i l i n 1 8 6 5a n d r his mind. Hе diеd in 1

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Louis Agassiz was a mastеr at rесonstruсtingfossil fish. Тlris Dartiсlrlar s.pесimеn' Сусlopomа spin(,sum,wаs giving him diffiсultyand th.n hе hаd а drеamin whiсh hе sаw thе full form. .Whеnhе еvеntuаllyсomparеd thе skеtсh that hе had madе from mеmory with thе aсtuаl еmЬеddеdspeсimеn.thе two сorrеspondеd ехaсtly.It is dеsсriЬеdin Agassiz 18з3_184J' vo|.4. Сtёnijides.

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t7-1873) as a Ьoy Was a kееn naturalist. Не iеs'еarningan advanсеd dеgrее in еputationas a Ьrilliant rеsеarсheг' iving and fоssil, and to his сarеful l 3 , l 8 4 0 ) ( s е еf i g u г е ) .B е g i n n i r l gi n n8 nеW thеory аЬout аn Iсе Agе' hеrn Еuropе. Aftег moving to thе rеriсa'slеadingsсiеntists,founding a r v a r di n 1 8 5 9 . thе puЬliс as wеll as his studеrrts еmbryсllogy'palеorrtologyJ аnd \gassizеmphasizedtlrе pattеrn of it had lorrg Ьееn known that thе thеiг ftrnсtion'not Llntil thе ninе.aсtthat divеrsесrеaturеs sееm to )г typе. VегtеЬrаtеsаrе onе suсh d othеr organs сan bе traсеd in a пprеssеdhis audiеnсеs with unfa. Ьееs,spidеrs,and loЬstеrs arе also sеs' snails' and сlirms, or starfish, lowing Gеorgеs Сuviег, hе сallеd rоllusks,аnd rаdiatеs.In his Еssa1'

oп Сlаssifcаtion (1859) Agassiz arguеd that homologiеs, whiсh ехtеnd aсross еmЬryoniс forms and Ьaсk thrоugh thе fossil rесord, arе еvidеnсe of thе ехistеnсе of ..one Suprеmе Iпtеlligеnсе'' who hаd сonсеivеd thеsе rеsеm_ blаnсеsЬеforе hе сrеatеd thеm. This aгgumеnt is quitе distinсt from thаt of William Palеy, whosе Nаtцrаl Thеologу (1s02) сomрarеd God to а Wаtсhmakеr or еnginееr who Ьuilds maсhinеs that arе сlеvеrly adaptеd to thеiг purposе.Agassiz's God is likе а musiсiаn or arсhitесtwho еnjoys playing sеv_ еral variations on a fеw Ьasiс thеmеs. Agassiz arguеd that еaсh spесiеs was thе produсt of a сlistinсt aсt of сrеation and сannot сhangе, Ьut hе цndеrstood gеologiсal timе and firmly rеjесtеdthе ЬiЬliсal story of сrеation. His сonсеpt of spесiеs was sеvеrеly сhallеngеdwhеn hе еnсountеrеd pеoplе of Afriсаn dеsс.,'t, and his rеsponsе doеshim no сrеdit. Не insistеd that human raсеs arе aсtually distinсt spесiеs, an opinion wеlсomеd Ьy slavе ownеrs' Darwin's on tbe Оrigin of Spеcies was a sеrious thrеat to Agassiz's intеrprеtationof naturе. Pointing to thе samе phеnomеna сitеd Ьy Agassiz, Darwin arguеd that homology and Ьiogеography are еvidеnсе of dеsсеnt from a сommon anсеstor, whilе thе adaptеdnеss of form to funсtion is еvidenсе for naturai sеlесtion. Bеfоrе long Agassiz's students and пrost of his сollеaguеs aссеptеdеvolution, if not natural sеiесtion, Ьut Agassiz nеvеr did. Travеling to Brazil in 1855 and to thе Galjpagos Islands in 1872 did nothing to сhangе hls mind. Hе diеd in 787З.

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106

Аlехаndеr в|BLloGRAPнY Agassiz,L. 1833-1843. Reсherсhеs Imprimеriе sur les PoissoпsFossilеs'NеuсhДtеl: dе Pеtitpiеrrrе. 184О.Еtudеssur lеs g!аciеrs.Nеuсhatеl:Jеnt еt Gаssmann. 1859.Еssayoп Сlаssфcаtioп'London:Frееthought PuЬlishing Сompany/Longman,Brown' Grееn,Longmans,& RoЬеrts,and TruеЬnеr& Сo. Rеprint(Е. Luriе' еd.),СamЬridgе,MA: НarvardUnivеrsityPress,1962. (Origirrаlly puЬlishеdin 1857 as Part I of L. Agаssiz,Сoпtributiсlпs to the Nаturаl Historу of thе UпitеdSrс/сs.Bostoп:Littlе, Brоwn.) L u r i е , Е . | 9 6 0 . L o u i s А g а s s i z : A L i f е i n S с i e п с е . С h i с а g о : U n i v е r s iСt yhoi сf а g o Prеss. .!И. Palеy, [1802]1819.Nаturаl Thеologу(СolleсtеdWorks,vol. 4). London: Rivingtс;n. Winsor,М. P. 1991.RеаdiпgtheShаpеof Nаturе:Сotпpаrаtiuе Zooklgу аt thе -lvl.P.W. Agаssiz Мuseum. Сl-riсago: Univеrsityof Сhiсago Prеss.

Alеxandеr, Riсhard D. (b. |929\ Riсhard D. Alехandеr was trainеd as an еntomologist at ohio Statе Univеrsity. Soon aftеr rесеiving his PhD ш'1954, hе r
dеr hypothеsizеd tha vеnt this sort of сor, groups. In сonnесtiс (1983) idеa that hurг сonfеrs in сomplех thought-out thеoriеs hairlеssnеss in adults nanсе and its impliс сomЬination of higl group-grouP сompеt сonfidеnсе and an еrr mеntion a fеw. Thеsс sеarсh by human Ье} Riсhard Alехandt Amеriсan Assoсiatiс Daniеl Giraud Еlliot thе Darwin Awаrd iI iсal Soсiеty (|986l,, Bеhavior Soсiеty (2(

o f S с i е n с е st n | 9 7 4 , ation for thе Advanr thе Animal Bеhavio havior and Еvolutior tifiс Award io 2ОО7 artiсlеs' and has tra portant сontriЬutior

вIвLIoGRAPH

Alеxаndеr,R. D. 1979 .Washington Prеss 1.987.Thе Bio 1 9 9 О 'H o ш D i Spеciеs.Ann Arbo PuЬliсаtion1. H u m p h r е y ,N . 1 9 8 3 .с Мiпd. oхiord: Oх ottе, D., and R. D. Alс Grуllidае).Philad

Altгuism

Thе ехistеnсе of altr profound сhaliеngе tions for altruism h: and еvеn есonomists illuminatеd thе und modеrn еvolutionаf

Аltruism

пs F ossilеs. Nеuсhаtеl: Imprimеriе Jеnt еt Gassmann. rrееthoughtPublishiпg rns,6{ RoЬеrts, and ТruеЬnеr & : Harvard Univеrsity Prеss, 1962. Agassiz, Сoпtri|эutioпs to thе r: Littlе, Brown.) Сhiсago: Univеrsity of Chiсago сtеd lИorhs,vol. 4). London: re: Сompаrаtit'е Zoologу аt thе _М'P.w. LiсаgoPrеss.

tomologistat ohio Statе Univеrhе took a position at thе Univеr:rе hе rеmainеd for thе rеst of his 2001).Еarly in his сarееr hе сonсation in thе singing insесts-thе first biologist to usе insесt songs е r o f m е t h о d o l o g i с a li n n o v a t i o n s 426 new spесiеs and gеnеra of in_ )st сompliсatеd hybrid zonе еvеr rcllifoliа'Hе also was a pionеег in : сontriЬutionsto thе undеrstandcn insесt songs' l-tlatingЬеhavior, of insесt Ьеhаvioг. .With a nцmbеr .еtiсalidеas about thе еvolution of lnfirmеd with thе disсovеry of еus attеntion to thе еvolution of hu. Humаn Аffаirs (1979) hе showеd oсial intеraсtionamong individцal rizеthеir inсlusivе fitnеss in anсеsd a largе amount of anthropologiIo Thе Biolсlgу of МorаI Sуstems man sеnsеof morality is a produсt humаn groups, whiсh favors any еr and Ьеttеr-unitеdsoсial groups. сistеnсе,as with all sехually rеpro:ivеintеrеst among individuals. As 'f gеnеtiсally urrrеlatеd pеoplе, prецp Ьесomеsmoге diffiсult. Alехan-

dеr hypothеsizеd that morality as a form of indirесt rесiproсity hеlps to prеvеnt this sort of соnfliсt and allows thе formation of largеr, Ьеttеr.unitеd groups. In сonnесtion with this idеa, hе ехpandеd Niсholas Humphrеy's (1983)idеa that human intеlligеnсеhas еvolvеd Ьесausеof thе advantagеsit сonfеrs in сomplеx soсial intеraсtions. Alехandеr has dеvеlopеd wеllthought-out thеoriеs aЬout a nunrbеr of human traits. Тhеsе inсludе rеlativе hairlеssnеssin adults, fеmalе orgasm' sеxual dimorphism, есologiсal dominanсе and its impliсations for soсiality, soсially imposеd monogamy, thе сomЬination of high patеrnity сonfidеnсе and multi.malе soсial groups' group.group сompеtition as a form of plaу, thе assoсiation of low patеrnity сonfidеnсеand an еmphasison utеrinе kinslrip, and сross-сousitlmаrriagе, to mеntion a fеw. Thеsе thеorеtiсal idеas arе thе foundation of mrrсh сurrеnt rеsеarсhby human Ьеhavioral есologists. Riсhard Alехandеr has rесеivеd a numЬеr of important honors: thе Amеriсan Assoсiation for thе Advanсеmеnt of Sсiеnсе Award (1961), tЬe Daniеl Giraud Еlliott Меdal Ьy thе National Aсadеmy of Sсiеnсеs (197I), thе Dагwin Award in Insесt Bеhavioral Есology Ьy thе Florida Еntomologiсаl Soсiеty (\986), and Distinguishеd Animal Bеhaviorist Ьy thе Animal Bеhavior Soсiеty (z00z). Hе Ьесamе a mеmbеr of thе National Aсadеmy of Sсiеnсеsin 1974, and has Ьееn еlесtеd a Fеllow of thе Amеriсan Assoсiation for thе Advanсеmеnt of Sсiеnсе, thе ohio Aсadеmy of Sсiеnсеs, and thе Animai Bеhavior Soсiеty. Hе was еlесtеd prеsidеnt of thе Human Bеhavior and Еvolution Soсiеty in 1995 and rесеivеd its Distinguishеd Sсiеntifiс Award in2О07. Hе has puЬlishеd four Ьooks and ovеr 130 sсiеntifiс artiсlеs,and has trainеd 32 studеnts, most of whom now arе making important сontributiоns to thе еvolutionary study of Ьеhavior. в|вLIoGRAPHY Alеxandеr,R.D. 1979' Dапtliпism апd Huntаn Аffаirs. Sеаttlе:Univеrsitуof WashingtonPrеss. 1987' The Biologу of Мorаl Sуstems.Hawthornе,NY: Aldinе dе Gruytеr. 1990.Ilot,tlDid Нumапs Еuoluе?Reflесtionsoп thе Uпiquеlу Uпiquе Spесiеs.Ann ArЬor: Univеrsityof Мiсhigan N4usеumo|,Zoo|ogу,Spесiаl PuЬliсation1. Humphrеy,N. 1983. Сoпsсiot.tsпеss Regаinеd:Сhаptersin thе Dеuеlopmепtof Мiпd. Оxford: Oхford UnivеrsitуPrеss' -Гbe ottе,D., and R. D. Alехandеr.1'983. Austrаliап Сriсhеts(orthoptеrа: Grуllidаe). Philаdеlphia:Aсadеmyof Nаtural Sсiеnсеsof Philadеlphia. -w. t.

Altruism Thе ехistеnсеof altruism in animаls and humans has posеd onе of thе most profоundсhallеngеsin еvolutionary Ьiology, and thе еvolutionary еxplanаtions for altruism havе influеnсеd psyсhologists, soсiologists, philosophеrs, .!Иhilе аnd еvеn есonomists. еvolutionary thеоry and empiriсal studiеs havе illuminatеdthе undеrstanding of altruism, it rеmains an aсtivе suЬjесt in mоdеrnеvоlutionary Ьiology and psyсhology.

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Аltruism Thе proЬlеm of аltruism is dividеd into two sеparatеЬut rеlаtеd issuеs:Ьi. ologiсal altruism and psyсhologiсаl altruism. In Ьiologiсal altruism, an organism pеrforms аn altruistiс aсt whеn thе aсt Ьеnеfits anothеr organism at a сost to itsеlf. Bеnеfits and сosts arе mеasurеd in tеrms of rеproduсtivе fitnеss. Suсh altruism is wеll doсumеntеd in many spесiеs. Vеrvеt monkеys аnd prairiе dogs havе sеntriеs at thе outskirts of сoloniеs that alеrt mеmЬеrs of thе сolony of approaсhing pгеdators,oftеn at thе сost of Ьесoming thе targеts of thosе prеdators. Psyсhologiсal altruism, whiсh is thе сolloquial sеnsе of thе tеrm, is intеntionally pеrforming an aсtion at onе's own сost in ordеr to Ьеnеfit anothеr. Thе Ьеnеfits and сosts for psyсhologiсally altruistiс aсts, howеvеr, nееd not havе anything to do with rеproduсtivе fitnеss. An еxamplе of a psyсhologiсаlly altruistiс aсt woцld Ье to plant a slow-growing trее, knowing full wеll that you will not Ьеnеfitfrom its shadе or fruit' Although Ьiologiсal and psyсhologiсal altruism arе sеparatеproЬlеms, thеorists havе offеrеd Ьiologiсal undеrpinnings for psyсhologiсal altrцism. Thе proЬlеm of altruism, Ьoth Ьiologiсal and psyсhologiсal, is at thе сеntеr of grounding a thеory of morality within Ьiology. I will disсussthе two kinds of altruism in turn. Altгuism sееms to Ье a prоЬlеm for еvolutionary thеory whеn looking at sеlесtion from an individual pеrspесtivе (i.е.,sеlесtion that oссuгs on thе lеvеl of organisms). If altruistiс organisms livе among sеlfish organisms' thе sеlfish оrganisms will always Ье morе fit than thеir altruistiс сountеrparts. ovеr timе, altruistiс individuals will Ье sеlесtеd out in favor of sеlfish onеs. For ехamplе, sеntry monkеys lowеr thеir fitnеss Ьy alепing othеrs to thе prеsеnсе of а prеdator. ovеr timе, sеlfish monkеys, onеs that do not takе thеir turn on watсh' would produсе morе offspring and еvеntually еliminatе any altruistiс gеnеs. Сharlеs Darwin' tnThе Desceпt of Маn (7871)' notiсеd this proЬlеm and ..although high hintеd at a solution: standard of moгality givеs Ьut a slight a or no advantagе to еасh individual man . . . an inсrеasе in thе numЬеr of wеll_еndowеd mеn and advanсеmеnt in thе standard of morality will сеrtainly givе an immеnsе advantagе to thе group,, (p. 1'66).Darwilr сontinuеs by suggеsting thet groups that сontain morе altruistiс individuals will out. сompеtе groups сomprisеd mainly of sеlfishindividLrals.From this pаssagе,it appеars that Dаrwin Was suggеstingthat sеlесtion сan oссur at thе lеvеl of groups' a radiсal dеparturе from his сorе afgumеnt aЬout thе importаnсе of sеlесtionamong individuals. Еvolutionary Ьiologists havе vaсillatеd in thеir aссеptanсе of this so-сallеd group sеlесtion argumеnt. Darwin's influеnсе gavе it grеat сrеdеnсе for dесadеs. It fеll from favor in thе 1960s undеr thе influеnсе of Gеorgе C. IWilliams's writings (e.g., 1966| aЬout sеlесtion and adaptation Ьесausе group sеlесtion for any attributе сamе to Ье сonsiderеd a Ьiologiсal rarity. onе of thе main proЬlеms with the group sеlесtion argumеnt is that сompеtition within a group will always favor thе sеlfish individuals, so that еvеn if groups of altruists arе morе fit as a group than groups of sеlfish individuals, thе groups of altruists will suffег suЬvеrsion from within. Rесеntly, lrowеvеr, .Wilson group sеlесtion nrodеls havе rесеivеd a spiritеd dеfеnsе.SoЬег arrd

(1998) arguе that' und( lесtion. If thе avеragе1 thаn thе avеragе fitnеss fitnеss сonsеquеnсеs of t a i n а p г е d o m i n a n г l у' suЬvеrsionfrom wirhi twееn groups' Althou1 workеd out and thе pll studiеs of flour Ьееtlеs sеlесtion modеl arе mе ratеly еxplain naturаl p not еxplаin how altru mutation in bеhaviora Ьеforе thеy Ьесomе nur A sесond rеаson foг paсt of lWilliam Hamilt has сomе to Ье known. havior is gеnеtlсallyЬa tivеs, with whoпr thеy altruistiс gеnеs througl \й/ith this еxplanation, Frоm а gеnе's-еyеviеw fiсе hеrsеlf for thе livеs of hеr gеnеs.But thе Ье foг thе сost of sеlf-saсr Kin sеlесtion appеar m o t h е r s d е f е n d i n gг h е i ехplanation is that it rе Ьut largеr familial rеla than distant onеs' Whi] sual or olfaсtory сuеs' tJ еffесtivе proхiеs for rеl that аrе сlosе Ьy'' will и Suсh aggrеgationсаn o( if dispеrsal from thе ho But how сan wе ехpli rеlatеd if group sеlесtio tion was artiсulatеd by гесiproсаl altruism. Aс< toward othеr organism This ехplanation doеs statеs in animals. A sta Ьеhavior of vampirе Ьa out fееding; howеvеr, v individual nееds. Vamр bats who havе rесеntly

Altruism o sеparatеЬut rеlatеd issuеs:Ьir. In Ьiologiсal altruisnr, an or:t Ьеnеfitsаnothеr oгganisrn at a in tеrms of rеproduсtivе fitnеss. y spесiеs.Vеrvеt monkеys and сoloniеsthat alеrt mеmЬеrs of at thе сost of Ьесoming thе tarlm' whiсh is thе сolloqtrial sеnsе сtion at onе'S own сost in ordеr lr psyсhologiсallyaltruistiс aсts, геproduсtivеfitnеss. An ехamplе з to plant а slow-growing trее' 'om its shadе or fruit. 'uismаге sеparatеproЬlеms, thеfor psyсhologiсalaltruism' Thе 'syсhologiсal,is at thе сеntеr of 4y.l will disсussthе two kinds of 'onary thеory whеn looking at sе. :lесtionthat oссurs on thе lеvеl of g sеlfishorganisms, thе selfish orltruistiссountеrparts.ovег timе, avor of sеlfish onеs. For ехamplе, ] othеrs to thе prеsеnсе of a prеddo not takе thеir turn on watсh' l y е l i m i n a t еa n y a l t r u i s t i сg е n е S . ( 1 8 7 1 ) ,n o t i с е dt h i s p r o Ь l е m a n d lard of morality givеs Ьut a slight . . an inсrеasе in thе numЬеr of rе standard of morаlity will сеroup'' (p. l66). Dаrwin ссlntinuеs 'rе altruistiс individuals will outi n d i v i d u a l s F. r o m t h i s p а s s a g е ,i t еlесtion сan oссur at thе lеvеl of rgumеntaЬout thе impoгtanсе of t thеir aссеptanсеof this so-сallеd 1се gavе it grеat сrеdеnсе for dе:rdеr thе influеnсе of Gеorgе С. эlесtion and adaptation Ьесausе Ье сonsidеrеd a Ьiologiсal rarity. sеlесtion argumеnt is that сompеsеlfishindividuals, so that еvеn if than gгoups of sеlfish individuаls, n from within. Rесеntly, howеvеr, .Wilson riritеd dеfеnsе. SoЬеr and

(|998) arguе that' undег сеrtain сonditions, altгuism сan Ье promotеd Ьy sеlесtion. If thе avеrаgе fitnеss of groups prеdominatеd Ьy altruists is grеatеr than thе avеragе fitnеss of groups prеdominatеd Ьy sеlfish individuals, thе nеt fitnеssсonsеquеnсеs of Ьеing an altruist may Ье positivе. Groups сan maintain a prеdominantly altruistiс population and dеfеnd thеmselvеs аgаinst subvеrsion from within if thеrе arе pеriodiс migrations of individuals Ьеtwееn groups. Althorrgh thе mathеmatiсs for group sеlесtion havе Ьееn workеd out and thе plausiЬility of thе thеory сonfirmеd with ехpеrimеntal studiеs of florrr Ьееtlеs, it is lеss oЬvious that thе rеquirеmеnts of thе group sеlесtion modеl arе mеt oftеn in naturе and thus that thе modеl will aссuratеly еxplain natural phеnomеna. Furthеrmorе' grouP sеlесtion modеls сannot ехplain how altruists, whеn initially rarе (as would happеn through mutation in Ьеhavioral traits), avoid Ьеing еliminatеd by sеlfish individuals Ьеfoгеthеy Ьесomе nutnеrous еnough to сгеatе a group sеlесtivе advаntagе. A sесond rеason for thе есlipsе of group sеlесtion еxplanations is thе impaсt of William Нamilton's famous pаpеrs (|964a,1964ь) dеsсribing what has сomе to Ье known as kin sеlесtion. Нamilton arguеd that if altruistiс Ьеhavior is gеnеtiсally Ьasеd, thеn organisms that wеrе altruistiс toward rеlativеs,with whom thеy shаrе gеnеtiс matеrial, would promotе thе sprеad of altruistiс gеnеs through thе Ьеnеfits to thе rеlativеs that саrry thosе gеnеs. With this еxplanation, group sеlесtion was not nееdеd to ехplain altruism. From a gеnе's-еyеviеw it would bе sеlесtivеly nеutral for a mothеr to sасrifiсеhеrsеlf for thе livеs of two сhildrеn Ьесausе еaсh сhild possеssеsonе-half of hеr gеnеs.But thе Ьеnеfit of saving thrее offspring morе than сompеnsatеs for thе сost of sеlf-saсrifiсе. Kin sеlесtion apPеars сommonly in thе biologiсal world (just think of mothеrsdеfеnding thеir young). Onе potеntial proЬlеm for thе kin sеlесtion ехplanationis that it rеquirеs organisms to idеntify not only family mеmЬеrs but lагgеr fаmilial rеlationships, Ьeсаusе сlosеr геlativеs arе morе valuaЬlе than distant onеs. \iИhilе many organisms саn idеntify thеiг kin through visual or olfaсtory сuеs, thе kin sеlесtion argumеnt works еvеn if othеr сuеs arе еffесtivеproxiеs for rеlatеdnеss. A hеuristiс rulе likе ..sharе with organisms that arе сlosе Ьy'' will work whеn family mеmЬеrs tеnd to aggrеgatе in spaсе. Suсhaggrеgation сan oссuг еvеn in animals without advanсеd soсial systеms if dispеrsal from thе homе sitе is limitеd. But how сan wе ехplain altruistiс Ьеhavior Ьеtwееnorganisms that arе not rеlatеdif group sеlесtionis not thе answеr? A proposеd solution to this quеstion was artiсulatеd Ьy RoЬеrt Trivеrs (|97|) and has сomе to Ье known as rесiproсal altruism. Aссording to Trivеrs, an organism Ьеhavеs altruistiсally toward othеr organisms in thе ехpесtation that othеrs will hеlp it in rеturn. This еxplanation doеs not prеSupposе a сonsсious dесision oг еvеn mеntal statеsin animals. A standard ехamplе of гесiproсal altruism is found in thе Ьеhaviorof vampiге Ьats. Vampirе Ьats сan survivе only a day or two without fееding;howеvеr, vampirе Ьats that find prеy сan feеd in еxсеss of thеir individual nееds. Vampirе Ьats will oftеn sharе morе, and morе oftеn, with batswho havе rесеntly sharеd with thеm.

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Аltruism Rесiproсal altruism has thе advantagе ovеr kin sеlесtion in еxplaining altruistiс bеhavior toward unrеlatеd individuals. onе quеstion, howеvеr, is whеthеr rесiproсal altruism is rеally altruistiс. It сould Ьe arguеd that thе altruist is not paying a rеal сost Ьut only dеlaying its rеward fоr hеlping othеrs (imaginе a sсеnario whеrе two businеssеsсoopеratе with еaсh othеr in ordеr to maхimizе thеiг own utility). This proЬlеm and а sеriеs of morе сompliсatеd faсеts of altruism, еspесially rесiproсal altruism, havе bееn ехplorеd еxtеnsivеly Ьy thеorеtiсians using gamе thеory, and gamе thеorеtiс trеatmеnts hаvе Ьесomе a fertilе arеa foг dеvеloping nеw idеas about altruism and making nеw prеdiсtions aЬout Ьеhavior in nаturе. (Plеasеsее thе alpha..Gamе Ьеtiсаl еntry thеory'' foг a morе thorough trеatmеntof thе issuе.) Biologiсal altruism сan Ье usеd аs a foundation for studying psyсhologiсal altruism. Thе major diffеrеnсе Ьеtwееn thеm is that altruistiс traits manifеst thеmsеlvеsas psyсhologiсal traits in humans, as opposеd to Ьеing prеsеntеd as Ьеhaviorаl traits in thе nonhuman Ьiologiсal world. Darwin suggеstеdthat psyсhologiсal altruism, or morality morе gеnеrаlly,сould Ье ехplainеd by thе еmotion of sympathy, whiсh may havе Ьiologiсal roots. Similar еmphasis on thе role of еmotions in еthiсal Ьеhavior сan Ье found in thе work of thе ohilosophег Dаvid Нumе. Howеvеr, onе nееd not havе а Ьiologiсal еxplanation of psyсhologiсal altruism. Мorality, for eхamplе, may Ье a produсt of rationality and not Ьiology. Furthеrmore' thеrе arе а numЬеr of quеstions aЬout psyсhologiсal altruism that arе not Ьiologiсal but philosophiсal in naturе. For ехamplе, doеs psyсhologiсal аltruism ехist аt all? Еgoism, thе viеw that all Ьеhаviors havе sеlfish roots' is dirесtly opposеd to psyсhologiсal altгuism. In this viеw, individuals who fееd thе starving massеs arе sеlfish Ьесausе it givеs thеm plеasurе and sеlf-satisfaсtion to do so. Howеvеr, Aristotlе (among othеrs) notеd that sim. ply Ьесausе a fеeling of sаtisfaсtion ассompaniеs ..аltruistiс'' aсts, it doеs not follow that thе aсt Was pеrtormеd in ordеr to aсhiеvе thе dеsirеd {ееlinя. в|BLloGRAPHY Darwin, С. 1871.Thе Dеsсеntof Мап. [-ondon: John Мurray. Thе gеnеtiсalеvolutionof soсiаlЬеhaviourI,Jollmаl of Нamilton,\W.D.1,964a. ThеoretiсаIBiolrэgу7: 7-16. |964ь. Thе gеnеtiсalеvolutionof soсiаl ЬеhaviourII.Jourпаl ofThеoreticаl Biologу 7: 1'7-52. R o s е n Ь е г g^,. \ 9 9 2 . A l t г u i s m : T h е o r е t i ссаoln t е x t sI.n I ] . F . K е l l е r a n d Е . A . L l o y d , eds.,Kе1,шords in ЕuolutioпаrуBkllogу,19-28. СamЬridgе,МA: Hаrvаrd UnivеrsityPrеss. SoЬеr,Е., and D. S. Wilson. 1998' Uпto otЬеrs: The Еt,olutioпапd Psусhologуof Uпsel|ishBеhаuior.СamЬridgе,MA: Нarvard UnivеrsityPrеss. of Trivеrs,R, L. t971, Thе еvolutionof rесiproсаlaltruism.Thе Qиаrtеrlу Reuiеt,l, Biologу46: З5-57. Prinсеton,NJ: Рrinсеton \Иilliаms,G, С, 1966. Adаptаtioпапd Nаturаl Sеlесtiсlп. -1.2. UnivеrsitуPrеss.

Alvaгеz, Waltеr (b. .Walter

АLvarez, thе gеol varez and grandson of r was Ьorn oсtoЬеr 3, 19 Сarlеton Сollеgе io |96, tation on thе struсtuге o arсhеologiсal gеology' v. ing to thе study of mass .

Univеrsity of CaIiforniа honors, inсluding thе G еlесtion to thе Natiоnal Arts and Sсiеnсеs.In 19 makеr namеd a minor р attriЬuting thе еnd-Сrеt .!7idеspr rеstrial oЬjесt. еxtеnsivе tеsting and сor еxplanations for еvеnt

strophism. A l v a r е z ' s s i g n a lс o n t r trial сausеs for еxtinсtr Rathеr, hе gavе thе thе< allowеd еarth and planс suЬsidiary lrypothеsеsgс First puЬlishеd in 19 anomаlous dаta сollесtс .W.. Alvar 1980; sее аlso long rеgardеd thе ехtinс erthеlеss,in gеologiсalti еnt rapidity сould havе t at thе еnd of thе Сrеtaс sеdimеnt would rеprеsе mеasuгing thе amount .

Ьoundary layеr. Iridir'lm most еntirеly aЬsеntin t rain of сosmiс dust froп K-T Ьoundаry sеdimеn sеdimеntаtiоn. Samplеs bio. ltaly. showеdan iг slowеd sеdimеntation. l an еxtratеrrеstrialimpa Alvarеz and his grou and Неlеn Мiсhel, stru gеologiсal еvidеnсеthat thе еnd of thе Crеtaсеot agеs of tеrrеstrial and r

Аluаrez r kin sеlесtion in ехplaining alrls. onе quеstion. howеvег. is :.It сould Ье arguеd that thе alng its rеward for hеlping othеrs )pеratеwith еасh othеr in ordеr n and a sеriеs of morе сompliLl altruism, havе Ьееn еxplorеd 'ory, аnd gamе thеorеtiс trеatlping nеw idеas aЬout altruism in naturе.(Рlеasеsее thе alphaough trеatmеntof thе issuе.) ation for studying psyсhologiсal r is that altruistiс traits manifеst i, as opposеd to Ьеing prеsеntеd :al world. Darwin suggеstеd that еrally,сould Ье еxplainеd Ьy thе 'giсal roots. Similar еmphasis on Ье found in thе work of thе phiехplanation of psyсhologiсal allduсt of rationality and not biol. ions aЬout psyсhologiсal altruism aturе.For ехamplе, doеs psyсhow that all Ьеhaviors havе sеlfish ltruism. In this viеw, individuals :ausе it givеs thеm plеasurе and э (among othеrs) notеd that sim. ..altruistiс'' aсts, it doеs not tniеs э aсhiеvе thе dеsirеd fееling.

JohnМurray. of soсialЬеhaviour|. Jourпаl of Ьеhaviour1I.Jourпаl of ThеoretiсаI : x r sI. n Е . F . К е l l е rа n d Е . A . L l o y d , -28. СamЬridgе,МA: Harvard Тhе Еuolutioпапd Psуcbologу of LrdUnivеrsityPrеss. altruism.Thе Qиаrtеrlу Reuieu,,of

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lr|varcz,.Wаltеr(ь. t9 40) !Иaltеr,Ц|varez,thе gеologist son of NoЬеl Prizе_winning physiсist Luis Al.lfaltеr С. Alvarеz, varez aпd grandson of wеll-known Сalifornia physiсian was Ьorn Oсtobеr З, 1940, in Bеrkеlеy, California. Hе еarnеd his BA from Сarlеton Сollеgе io |962 and his PhD from Prinсеton ln 1967 with a dissеrtation on thе struсturе of thе Andеs Мountains. А|уarez workеd in orogеny' arсhеоlogiсal gеology' volсaniсs' tесtoniсs, and palеomagnеtism Ьеforе turning to thе study of mass ехtinсtions.Hе hаs spеnt thе Ьulk of his сarееr at thе Univеrsity of Сalifornia at Bеrkеlеy and has rесеivеd numеrous awаrds and honors, inсluding thе Gеologiсal Soсiеty of Amеriсa's Pеnrose Меdal, and еlесtionto thе National Aсadеmy of Sсiеnсеs and thе Amеriсаn Aсadеmy of Arts and Sсiеnсеs.In 1985, thе planеtary sсiеntistsGеnе and Сarolyn Shoеmakеr namеd a minor planеt for him. А|уarez is Ьеst known for his thеory attriЬuting thе еnd-Сrеtaсеous mass еxtinсtion to thе impaсt of an ехtratеr.\Widеsprеad rеstrial oЬjесt. rеspесt for how thе thеory hаs hеld up undеr ехtеnsivеtеsting and сorrесtion has Ьolstеrеd aссеptanсе of othеr nongradual ехplanations for еvеnts in еvolutionary history and promotеd nеoсatastrophism. Alvarеz's signal соntriЬution liеs not in originating thе idеa of еxtratеrrеs. trial сausеs for еxtinсtion-suсh suggеstions go Ьaсk hundrеds of yеars. Rathеr, hе gavе thе thеory a logiсal struсturе and еvidеntiary Ьasе that has allowеd еarth and planеtary sсiеntists as wеll as Ьiologists to tеst thе many subsidiaryhypothеsеs gеnеratеd. First puЬlishеd in 1980 ln Sciепсe, thе Alvarеz argumеnt grеw out of anomalous datа сollесtеd to tеst а diffеrеnt hypothеsis (L. !и. Alvarеz еt al. .s7. 1980;sее also А|varеz et a|. 1984|. Thе palеontologiсal сommunity had long rеgardеdthе ехtinсtion of dinosaur linеagеsas a gradual proсеss. Nеverthеlеss,in gеologiсal timе thеir dеmisе appеarеd rathеr aЬrupt. This apparеntrapidity сould havе Ьееn ехplainеd by unusually slow sеdimеntatron ratеs at thе еnd of thе Сrеtaсеous. trfsеdimеntation wаs vеry slow, a thin layеr of sеdimеntwould rеprеsеnt a largе sliсе of timе. To tеst this, Alvarеz proposеd mеasuringthе amount of iridium prеsent in thе Сrеtaсеous-Tеrtiary (K-T) Ьoundary layеr. Iridium' a vеry hеavy еlеmеnt of thе platinum group, is almostеntirеly aЬsеnt in thе еarth's сrust; thе only sourсе is thе tiny Ьut stеady rain of сosmiс dust from spaсе. An inсrеasе in thе prеsеnсе of iridium in thе K-T Ьoundary sеdimеnts would indiсatе a slowеr than usual rаtе of еarth sеdimеntation.Samplеs takеn in |979 from thе ехposеd K-T layеr nеar GuЬЬio, Italy, showеd an iridium spikе far in ехсеss of anything attriЬutаЬlе to slowеdsеdimеntation. Aссordingly, А|varez invеstigatеd thе possiЬility that an ехtratеrrеstrialimpaсt had сontriЬutеd thе iridium. Alvarеz and his group' inсluding Luis Alvarеz and сhеmists Frank Asaro and Hеlеn Мiсhеl' stгuсturеd thеir argumеnt in thrее parts. Thеy mustеrеd gеologiсalеvidеnсе that an astеroid or сomеt had indееd struсk thе еarth аt thееnd of thе Сrеtaсеous.Thеn' thеy assеmЬlеdthе сasе that numеrous linеagеsof tеrrеstrial and marinе organisms had indееd Ьесomе еxtinсt at that

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Amphibiапs timе. Having еstaЬlishеd thе two еvеnts and thеir synсhrony, thеy еlaЬoratеd thе есologiсal impliсations-that a largе impaсt hаd сausеd a dust сloud to еnсirсlе thе еarth, сutting off photosynthеsis and making it сold and dark for a suffiсiеntlv long pегiod so that virtuallv all land animals ovег 50 pounds diеd' along with somе 7 5"Ь of marinе organisms-and drеw thе infеrеnсе that thе impaсt had сausеd thе ехtinсtion of a largе fraсtion of spесiеs 65 million years ago' inсluding thе ехtinсtion of dinosaurs. Alvarеz's framing of thе issuеs providеd a Ьroad Ьasis for analysis in divеrsе fiеlds. His original artiсlе has Ьееn сitеd thousands of timеs in hundrеds of sсiеntifiс journals from Ьiology and gеology to mеdiсinе and nuсlеar physiсs. Thе original hypothеsis has bееn strеngthеnеd Ьy furthеr disсovеriеs, most dramatiсally by dirесt еvidеnсе of thе impaсt providеd Ьy thе Chiсxu. lub сratеr and its uniquе сhеmiсal signaturе. Furthеr, thе thеory has сapturеd thе popular imаgination, inсrеasing intеrеst in sсiеntifiс invеstigation and promoting undеrstanding of thе unity of sсiеnсе. Ь1уarezhas himsеlf writtеn a popular aссount of thе disсovеry of thе ехtratеrrеstrial impaсt and its impliсations for lifе on еarth in Т. Re.lсапd the Сrаter of Doom (1,997). B|вLloGRAPHY Alvarеz, L..vи.'.!(/.А|varеz,F. Asaro, and H. V. Miсhеi. 1980. Еxtratеrrсstrialсausе for thе Сrеtaсеous-Tеrtiary ехtinсtion'Sсiепсе208: 1095_1108. Alvarеz, \/. 1997. T. Rех апd thе Сrаtеr of Doon. Prinсеton'NJ: Prinсеtоn UnivеrsityPrеss. Alvarеz, !и.' Е. G. Kauffmann' F. Surlyk, L. !И. Alvаrеz, F. Asaro, and H. V. Мiсhеl. 1984. Impaсtthеoryof mаssехtinсtionsand thе invеrtеЬratеfossil rесord. -P.NI.P, Sсieпсe 22З:,l',l'З 5 -1'1'4 1'.

Thе еastеrnspadеfоo notiсеd inhaЬitantof t ехplosivеly in thе spri grow rapidly and mеtа fееd on insесts аnd ott intсl sandy soil ttl аwa is part of an old linеa Statеs,whсlsеtadpolе dеsеrtin аs littlе as 10

AmphiЬians LimЬеd vеrtеbratеs arosе morе tЬan 37 5 million yеars ago in thе Dеvonian pеriod and thеy arе gеnеrally сallеd amphiЬians. This was a vеry divеrsе assеmЬlagе of aquatiс and tеrrеstrial animals, ranging from thе sizе of a salamandеr to largеr than an alligator. Somе of thеm еvеn Ьесame limЬlеss. But by thе еnd of thе Palеozoiс pеriod and thе grеat Pеrmian ехtinсtion, aЬout 300 million yеars ago' most of thе linеagеs Wеrе ехtinсt. A fеw thrivеd in thе еarly Меsozoiс pеriod Ьеforе thеy, too, disappеarеd. Rесеnt amphiЬians and thе amniotеs rеprеsеnt thе living dеsсеndantsof this еarly radiation. Thеrе arе thrее vеry diffеrеnt kinds of living amphiЬians. Pеrhaps thе most familiaг and сеrtainly thе most numеrous and widеsprеad arе thе frogs, whiсh arе found on еvеry сontinеnt ехсеpt Antarсtiсa and еvеn on a fеw oсеaniс islands (sее figurе). Thе salamandеrs arе wеll known to inhaЬitants of thе north rеmpеratе zonе, Ьut only onе linеage has aсhiеvеd any suссеss in thе tropiсs. In сontrast' thе rеlativеly unfamiliar and sесrеtivе сaесilians arе rеstriсtеd to tropiсal rеglons. Rесеnt amphiЬians diffеr dramatiсally fгom еaсh othеr in struсturе and way of lifе. All hаvе moist skins, howеvеr, and rеspiration is largеly сutanеous.

Most salаmandеrs, Although amphiЬian еntеr watеr. Frogs (Anura), wit tail, and wеll dеvеlop suЬdivisions. Many 1 adults, thеy сatсh prс toriеs, Ьut thе most g in ponds in thе spriг qualitiеs of thе mal whiсh arе gеnеrallyl tivе tadpolе, a larva sеason' during whiсh algaе or vеgеtаtion.I Tadpolеs may livе m. Мany frogs havе no that dеvеlop dirесtly

Аmphibiаns thеirsynсhrony,thеy еlaЬoratеd paсt had сausеd a dцst сloud to and making it сold and dark for 'll land animals ovеr 50 pounds rnisms_and drew thе infеrеnсе lf a largе fraсtion of spесiеs 65 f dinosaurs. a Ьroad Ьasis fоr analysis in dil thousandsof timеs in hundrеds ology tо mеdiсinе and nuсlеar еngthеnеdЬy furthеr disсovегiеs, impaсt pгovidеd Ьy thе СhiсхuFurthеr, thе thеory has сapturеd ;t in sсiеntifiс invеstigation and еnсе.Alvaгеz has himsеlf writtеn кtratеrrеstгialimpaсt and its iml Сrаtеr of Doom (|997).

Мiсhеl. 1980.Еxtratеrrеstrialсаusе r c е2 0 8 . . 1 0 9 5 _ 1 1 0 8 . ,z. Prinсеton, NJ: Prinсеtоn Alvarеz,F. Asaro,and H. V. Мiсhеl. fossil rесord. d thе invеrtеЬratе -Р.М.P.

rillion yеars ago in thе Dеvonian эians. This was a vеry divеrsе as' ranging from thе sizе of a salaf thеm еvеn Ьесamе limЬlеss. But ) grеat Pеrmian ехtinсtion, aЬout Wеrееxtinсt. A fеw thrivеd in thе rppеarеd.Rесеnt amphiЬians and :sof this еarly radiation. Thеrе arе rns.Pеrhaps thе most familiaг and rd аrе thе frogs, whiсh arе found :vеnon a fеw oсеaniс islands (sее inhaЬitantsof thе nоrth tеmpеratе suссеssin thе tropiсs. In сontrast, ilians arе rеstriсtеdto tropiсal rеlffIеaChothеr in struсturе and waу l rеspiration is largеly сutanеous.

Тhе еastегnspаdеfoot toad, Scаphiopus bolbrookii, is а сommorr Ьuг littlе_ notiсеdinhaЬitantсlf thе southеastеrnUnitеd Statеs'Spadеfoottoads Ьrееd ехplosivеlyin thе spгingin еphеmеralponds aftеr hеavyrains;thе tadpolеs grow ra;lidlyand mеtamorphosеin aЬout thгееwееks.Thе juvеnilеsand adults fееdсlrrinsесtsаr-rdtlthеrsmаll аnimals in thе littеr layеr of forеstsarrdЬurrow into sandy soil to аwait thе nехt oppсlrtr-rnity to еmrrgе and Ьrееd.This spесtеs is рart of an old linеagеof frogs with rеprеsеntativеs in thе southwеstеrnUnitеd Statеs,r.l'lrosе tаdpolеsсan сoп-rplеtе dеvеlopmеntin еphеmеralpools in thе dеsеrtin аs littlе as 10 dаys.

Мost sаlаmandеrs, a fеw fгogs, and onе саесiliаn laсk lungs еntiгely. Although amphiЬians arе assoсiatеdwith moisr haЬitats' many spесiеsnеvеr еnтеrwatеr. Frogs (Anura), with moге than 5,500 spесiеs,havе vеry short Ьodiеs. no tail, аnсlwеll dеvеlсlpеdlimЬs, еspесiallylong hind limЬs tlrаt havе foцr main suЬdivisions.Мaпy frogs arе сapaЬlе of prodigious lеaps. Сarnivorous as adults,thеy сatсh prеy with projесtilе tonguеs. Fгogs display divеrsе life historiеs'Ьut thе most gеnеral аnd familiar is onе in wlriсh rhе sехеsсongrеgatе in porrds in thе spring, witlr fеmalеs sеlесting malеs as mаtеs Ьasеd on thе qualitiеs of thе mаlе сall. Mating involvеs еxtеrnal fеrtilization of еggs, whiсh arе gеnеrallv Iaid in сlustеrs сlr strings. Еggs dеvеlop into thе distinс_ tivе tadpolе, a lаrval forrrr uniquе to Гrogs.Tаdpolеs typiсally livе for onе sеаson'during whiсh timе thеy сonsumе primary produсtivity in thе form of algaеor vеgеtation'Howеvеr, thеrе аrе many variаtions on this lifе lristory. Тadpolеsmay livе more than onе yеar Ьеforе nrеtamorphosinginto froglеts. Маny frogs havе nсl larval stagе at all Ьut lаy largе еggs in small numЬеrs that dеvеlop dirесtly into miniaturеs of thе adult. othеr frogs havе tadpolеs

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Amphibiапs that may Ье Ьroodеd in spесial сompartmеnts thаt form in thе skin of thе baсk, in spесializеd pouсhеs on thе Ьaсk, in thе voсal saсs of malеs, or in divеrsе есologiсal settingssuсh аs arЬorеal Ьromеliads.A fеw frogs arе vivip. arous' with еggs dеvеloping in thе fеmаlе rеproduсtivе traсt' whеrе thеy rесеivеnourishmеnt. Salamandеrs (Сaudata), with morе than 560 spесiеs'rеsеmЬlеanсiеnt amphiЬians morе сlosеly than do frogs or сaесilians. Thеy arе gеnеralizеd in struсturе' with a Ьody of modеratе lеngth, a wеll-dеvеlopеd tail, and two pairs оf limЬs, with thе hind limЬs Ьеing only a littlе longеr than thе forеlimЬs. Неads of salamandеrs arе rеlativеly smаllеr than thosе of frogs, Ьut Ьoth groups havе wеll-dеvеlopеdеyеs and ехсеllеnt vision. Salamandеrsoftеn gathеr in ponds to Ьrееd Ьut mаlеs havе no сalls. Larvaе arе сarnivorous rathеr than hеrЬivorous) and mеtamorphosis is far lеss dramatiс than in frogs. Somе spесiеs rеmain in а pеrmanеntly larval or sеmilarval statе and somе lаrvaе Ьесomе vеry largе. Мost сladеs оf salamandеrshavе somе variаtion of thе Ьasiс lifе histoгy, Ьut thе most suссеssfulаnd numеrorrssalamandеrs, in thе family Plеthodontidaе, havе dirесt dеvеlopmеnt' and it is only thеsе that havе suссеssfully invadеd thе tropiсs (rеstriсtеd to tropiсal Amеriсa). A fеw spесiеsof salamаndеrsarе vivipаrous. C a е с i l i a n s ( G y m n o p h i o n a ) a r е l i m Ь l е s sa n d е x t r е m е l y е l o n g a t е ,w i t h е i thеr a vеry short tail or no tail. Thе hеad is aЬout thе samе diametеr as thе strongly sеgmеntеd trunk, and thе еyеs arе inсonspiсutlus or invisiЬlе. A uniquе sеnsory organ, thе tеntасlе, is formеd from сomponеnts of thе nosе and еyе and providеs еnvironmеntal information to thеsе mainly Ьurrowing animals. Somе сaесiliаns havе aquatiс larvaе Ьut m()st havе еithеr di. r е с t d е V е l o p m е n to r a r е v i v i p a r o u s .A m o n g t h е m а n y v i v i p а г o u ss p е с i е s a r е f o r m s t h a t a r е е х с l u s i v е l yа q u a t i с . T h е r е a r е a p p r o х i m а t е l y 1 7 0 с a е сilian spесiеs. Amphibians play impоrtant Ьut gеnеrally undеrapprесiatеd rolеs in есosystеms.Frogs arе important prеdators as adults, Ьut thеir larvaе сan bе important сonsumеrs in equatiс systеms.Rеmoval of tadpоlеs from strеams сan quiсkly lеаd to ovеrgrowths оf algaе and forrтation of largе algal mats. Although salamandеrs arе сryptiс and lеss oЬvious than frogs, in somе есosystеms thеy сan Ье ехtrеmеly numеrous. As сarnivorеs, thеy сontriЬutе to rеgulation of tеrrеstrialfood wеЬs. MеmЬеrs of thе soil сommunity' сaесilians arе major сonsumеrs of еarthworms, Ьut thеir есologiсal rolе is lеss wеll undеrstood than that of frogs and salamandеrs. AmphiЬians havе rесеivеd attеntion Ьесausеof сonсеrns aЬout еvidеnt dесlinеs and ехtinсtions сlf populations as wеll as spесiеs throughout thе world. A rесеnt assеssmеntof thе stаtus of amphiЬian spесiеs aсross thе gloЬе found that a highеr proportion (morе than onе-third) Wеrе at risk of ехtinсtion than for any of thе othеr vеrtеЬratе taхa. Еspесially trouЬling Was thе finding that a largе pеrсеntagеof thе dесlinеs Wеrе from unknown .Whilе сausеs. most amphiЬian dесlinеs douЬtlеss arе rеlatеd dirесtly to habitat dеstruсtion аnd modifiсation Ьy humans, thеге arе also othеr impсlrtant faсtors. Onе infесtious disеasе,a сhytrid fungus that аttaсks thе kеratin

of thе skin and lеads to dt с l i n е s i n s p е с i е sl i v i n g i n 1 California, whеrе еpidеm idly, and thеrе is no know pliсatеd in thе dесlinеs с faсtors inсludе еffесts of tion from pеstiсidеs and thеse faсtors and othеrs many parts of thе planеt zlеmеnt ovеr thе dесlinеs. Today's living amphiЬia jor group сan Ье traсеd Ьa to Ье dеliсatе, thеy wеrе trouЬling that amphibran should Ье faсing еxtinсtlo в|BLIoGRAPHY

Duеllman,.W.Е., and L. Tru Hill. Hutсhins, N4.'!и. Е. Duеilm Епсусlopеdiа.2nd еd.V Lаnnoo, M. 2005.Аmphibi Spесiеs.Bеrkеlеy:Univе Stuart,S. N., J. S. Сhanson,J .!7 Fisсhman,аnd R. !(. еxtinсtionsworldwidе.j .Wеlls, K. D. 20О7.Тbe Еcolс of СhiсagoPrеss.

Andеrson, Еdgar (18

Еdgar Andеrson is rеgard tionary Ьiology during thе intеllесtual traditions, Anr in gеnеtiсs and сytology t systеmatiсs.Hе is Ьеstknс natural sеttings and for hyЬridization, a proсеssЬ; hyЬridization and Ьaсkс l949 with thе puЬliсatio tioп. TЬe Ьook was widеl сontriЬution to plant gеn еvolution. Andеrson, Ьorn in Forс а d m i n i s t г а t o ra n d a p i a n i thе }иIiсhiganAgriсultural Andеrson was thrее. Froп

Aпdersoп гs that forrn in thе skin of thе thе voсai saсs of malеs, or in l m е l i а d sA. f е w f r o g s a r е v i v i p 'roduсtivеtraсt, whеrе thеy rе0 s p е с i е sr' е s е m Ь l еa n с i е n t a t n :ilians.Thеy arе gеnеralizеd in а wеll.dеvеlopеdtail, and two ly rr littlе lorrgег than thе forеmallеr than thosе of frogs, but tсеllеntvision. Salаmandеrs of. l t l с а i l s ' L а г v а еа r е с а r n i v < l r o u s ;is is far lеss dramаtiс thаn in y larvirl оr sеmilarval statе and l [ s a l а r n а л d е rhse v е s o m е v а r i а ;сеssfцlаnd nцгnеroussalatnanесt dеvеlopшеnt' and it is only liсs (rеstriсtеdto tropiсal Amеrfous. ,nd еxtrеmеly еlorrgatе,with еia b o u tt h е s a m е d i a m е t е r a s t h е е inссlrrspiсuousor invisiЬlе. A :d frorт сomponеllts of thе nosе тation to thеsе mainly Ьurrow. larvaе but most havе еithеr din g ,r h е n l а r r yv i v i p a r o u s s p е с i е s еrе arе approximatеly 170 сaе:ally Lrndеrapprесiаtеdrоlеs in аs adults, Ьut thеir larvaе сan Ье еmovаl of tadpolеs from strеams rd formаtiоn of laгgе algal mats. ss oЬvious rharr frogs. in sonlе Ls.As сarnivorеs' thеy сontriЬutе r Ь е r sо [ t h е s о i l с o m m u n i t y , с a е ;, Ьut thеir есologiсаl rolе is lеss mandеrs. usеof сonсеrnsaЬout еvidеnt dеwеll as spесiеs throughout thе of аmphiЬian spесiеs aсross thе е than оnе-third) wеrе at risk of :Ьratеtaхa' Еspесially tгoubling :hеdесiinеswеге fronr unknown louЬtlеssаrе rеlatеd dirесtly to n а n s .t h с r еа r е а I s o o t h е r i m p o r id fungusthat аttirсks tlrе kеrаtin

of thе skin and lеads to dеhydration, is rеsponsiЬlеfor wеll-doсumеnted dесlinеsin spесiеsliving in protесtеd arеаs in Сеntral Amегiсa, Australia, and Сalifoгnia, whеге еpidеmiсs havе Ьееn rесordеd. Thе disеasе sprеads rapidly, and thеrе is no known Way to stop it. GloЬal сlimatе .h".'g. аlso is impliсatеd in thе dесlinеs of many frogs in tropiсal montanе forеsts. Othеr faсtors inсludе еffeсts of introduсеd spесiеs (е.g., for sport fishing), pollution from pеstiсidеs and fеrtilizеrs, and synеrgistiс intеraсtions of somе of thеsе faсtoгs and othеrs suсh as ultraviolеt гadiation (UVB). Howеvеr, in many parts of thе planеt amphiЬians rеmain aЬundant, adding to the puzzlеmеntоvеr thе dес1rnеs' Tоday's living amphiЬians arе rеmnants of a vеry anсiеnt linеagе; еaсh major group сan Ье traсеd Ьaсk аЬout 200 million yеars. Altho,.gh й,.,y appеar to Ье dеliсatе, thеy wеrе ruggеd survivoгs of many е*tin.tio., еvеnts. lt is trouЬlingthat amphiЬians that lived happily with thе long-ехtinсt dinosaurs should bе faсing еxtinсtion on oцr watсh' BlвLloGRAPHY .W. Duеllman, Е., and L. TruеЬ. 1986.Biologу of Amphibiаn's.Nеw York: МсGrаw. Hill. Hutсhins,M., )и. Е. Duеllman,and N. Sсhlagеr.20ОЗ.Grzimek's Аnimаl Li|е Епсуclopediа.2nd ed.Уo|. 6, Апphibiаns. FarmlngtonНills, МI; Gаlе Group. Lannoo,М. 200.'. Аmphibiап Dеclines:Thе Сonseruаtiс-lп Stаtusof (Jпitеd Stаtеs Spесiеs.Bеrkеlеy:Univегsityof Сalifoгnia Prеss. Stuart,S. N.' J. s. Сhanson,N. A. Сoх' B. Е. Young,A. s. L. Rodriguеs, D. L. Fisсhman'аnd R. W. Y/allеr.2004. Statusand1rеndsof amphiЬiаn dесlinеsand еxtinсtionsworldwidе.SсiепceЗО6 1783-1786. Wеlls,K. D.20О7. Тhе Есologу апd Behаuiorof Аmphibiаn.s'Сhiсago: Unrvеrsity of СhiсagoPгеss. D.B.w.

Andеrson, Еdgar(ts97-|969) Еdgar Andсrson is rеgardеd as onе of thе lеading sсiеntists of plant еvolutionаry Ьiology during thе twеntiеth сеntury. A produсt of а numЬЪr of divеrsе intеllесtuaitraditions, Andегson wаs aЬlе to synthеsizе nеwеr dеvеlopmеnts in gеnеtiсsand сytology to hеlp a.ddrеssmorе traditional proЬlеms in plant systematiсs. Hе is Ьеst known for his invеntivе studiеsmеasuring variation -i't.og..,,'u.in naturаl settings and foг his artiсulation of thе сonсеpt of hyЬridizatiоn' a proсеss Ьy whiсh nеw gеnеtiс matеrial is introduсеd through hybridization and Ьaсkсrossing. Muсh of this work was formalizеd in 1949 with the publiсation of а smаll volumе tit\ed Iпtrogrеssiuе Нуbridizаtion. The Ьook was widеly rеаd and immеdiatеly .есog.'i,.d as an original сontriЬцtion to plant gеnеtiсs that сould shеd light o' , g..'","l thеory of еvolution. Andегson, Ьoгn in Forеstvillе, Nеw York, wаs thе son of an еduсational administrator and a pianist. His fathеr Ьесamе a prоfеssor of dairy sсiеnсе at thеМiсhigan Agriсultuгal Сollеgе and movеd his family to Еast Lansing whеn Andегson was threе. Fronr аn еarly аgе, Andегsоn wаs fasсinаtеd Ьy plаnts.

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Аndеrson Hе was a kееn studеnt and in 1914 еntеrеd Miсhigan Agriсultural Сollеgе' whеrе hе studiеd Ьotany and hortiсulturе. In |9|9 he еntеrеd thе graduаtе program at Harvard, working at thе Bussеy Institution under thе supеrvision of notеd agriсultural gеnеtiсist Еdward Murray Еast. His rеsеarсh Was on thе gеnеtiсs of sеlf-inсompatibility in Nicotiаnа' thе toЬaссo plant, Ьut hе wаs also fond of arеas likе есonomiс Ьotany and gravitatеd to Oakеs Ames' thе notеd есonomiс Ьotanist at Harvard and ехpеrt on orсhids. Aftеr gradua. tion, Andеrson aссеptеd a position as gеnеtiсist at thе Мissouri Botaniсal Gardеn and was appointеd assistant profеssor at Washington Univеrsiry in St. Louis. |n 1929 hе aссеptеd a National Resеarсh Fеllowship to study in Britain's John Innеs Hortiсultural Institution, working with сytogеnеtiсist С. D. Dаrlington' statistiсian R. A. Fishеr, and gеnеtiсistJ. B. S. Haldanе. Aftеr rеturning from Britain, hе was influеnсеd Ьy Harvard gеnеtiсist Karl Sax. Мuсh of Andеrson's rеsеarсhwas spеnt dеvеloping novеl visual and quantitativе mеthods to mеasurе gеographiс variation in natural populations, thе Ьеst known of whiсh is thе idеogranr. Anderson is also known for his dеtailеd studiеs of thе pattеrns of variation in thе сommon Ьluе f|ag, Iris uеrsiсolor, a|ong thе Мississippi dеlta and what thе pattеrns rеvеalеd aЬоut meсhanisms of spесiation in plants. This study rесеivеd reсognition in thе ear|у 1940s, an intеrval of timе important in thе history of еvolutionary Ьiology, bесausе it fuеlеd thе movеmеnt known аs ..nеw systеmatiсs'' (or biosystеmatiсs),whiсh sought to Ьring intеrdisсiplinary insights from gеnеtiсs and есology to morе traditional taxonomy. As a rеsult, Andеrson еmеrgеd as onе of thе lеadеrs sееking gеnеral prinсiplеs of plant еvolution. Hе was invitеd to givе thе prеstigiousJеsup Lесturеs at СolumЬia Univеrsity along with avian systеmatistЕrnst Mayr in 1941. Andеrson Was to providе thе plant sidе of thе nеw systеmatiсs.Although hе gavе thе lесturеs,hе did not сonrplеtе thе rеquirеd mаnusсript for a Ьook Ьasеd on thеm. Thе сomplеtion of this manusсript would havе plaсеd Andеrson within thе сirсlе of arсhitесts of thе еvolutionary synthеsis of twеntiеth-сеntury еvolutionary Ьiology. Thе rolе of Ьotaniсal arсhitесt еvеntually fеll to his сlosе friеnd, G. Lеdyard StеЬbins. Andеrson's failцrе to сomplеtе thе manusсript was part of his еrrаtiс pеrformanсе pattеrn. Hе was а nonсonformist who fгеquеntly еngagеd in variеd intеrеsts that сompеtеd foг his timе. Не did makе notaЬlе сontribuгions to arеas in hortiсulturе and еvеn Ьесamе thе dirесtor of thе Missouri Botaniсаl Gardеn. In thе 1940s, hе inсrеasingly turnеd to quеstions important to undеrstanding hyЬridization in maizе, with his intеrеstsdiгесtеd toward есonomiс Ьotany. A talеntеd individual with a strong pеrsonаlity, Andеrson lеft his imprint on thе history of plant еvolution. For thе lattеr part of his lifе hе was plaguеd with еm
вIвLloGRAPHY

Andеrson' Е. 1'949.lпtrсlgr Klеinman'K. 1'999.Нis ow thеory in thе 1940s./о Smoсovitis,V. B. 1999.Еd1 eds',AtпеriсаrtNаtioп UгrivегsityPrеss. StеЬЬins,G. L. 1978.Еdga Меmoirs 49 З-23.

AnimаI Speciеsаnс

A. J. Cain's АпimаI Spе first сomprеhеnsivе disс еring of thе so-саllеd mt Ьiogеography' taxonom. сohеsivе tгеatmеnt of s and thе rolеs of natural t е r n s o f с h a r a с t е rv a r i а t Ьooks; howеvеr, it was l thеsis that madе Сain's l prеsеntеd in this slim v oaks and from sеа urсlri Саin traсеs an arс fr сussing traditional idеa tion, and taxonоmiс rar

Р. oсп:

.# P. iсtnotis

T h е g r a d u a l v a r i a t i о nt l rаkеn аs onе trf thе Ьеsr i g е o g r a p h i с a vl а r i а t i с l n

Animal Soесiеsand Thеir Еvolution c Мiсhigan Agriсultuгal Collеgе, In t91r9 hе еntеrеd thе graduatе l n s г i t u t i o nu n d е г t h е s u p е r v i s i o n :ray Еast. His rеsеarсh was on thе с' thе toЬaссo plant, Ьut hе was rd gravitatеd to Oakеs Amеs' thе ехpегt on orсhids. Aftеr graduаlеtiсistat thе Мissoцri Botaniсal .!7ashington Univеrsity in ssor at Rеsеarсh Fеllowship to study in .ion'working with сytogеnеtiсist ., and gеnеtiсist B. S. Haldanе. J' rflцеnсеd Ьy Harvaгd gеnеtiсist dеvеlopingnovеl visual and quanriation in nаtцral populations, thе tdеrsonis also known for his dеn thе сommon Ьluе flag, Iris uersiyhat thе pattеrns rеvеalеd aЬout study rесеivеd rесognition in thе г in thе history of еvolutionary bi..nеW systеmatiсS'' (or known as rегdisсiplinary insights fгоm gеnеtxonomy. As zr rеsцlt, Andеrson rеral prinсiplеs of plant еvolution. . p I , е с t u r еas t C o l u m b i a U n i v е r s i t y ln 7941'.Andеrson Was to providе hough hе gavе thе lесturеs, hе did . a Ь o o k Ь a s е do n t h е m . T h е с o m aсеd Andеrson within thе сirсlе of twеntiеth.сеntury еvolutionary Ьiеntually fеll to his сlosе friеnd, G. rusсгiptwas paгt of his еrratiс pеrst who frеquеntly еngagеd in variеd did makе notaЬlе сontriЬutions to : dirесtor of thе Мissouri Botaniсal rnеd to quеstions important to unr his intеrеstsdirесtеd toward есo. :sonality,Andеrson lеft his imprint thе lattеr part of his lifе hе was lhiсh hе was hospitalizеd. Hе was anist,and had onе сhild. Hе diеd in hе grounds of thе Missouri Botaniсal

B|вLIoGRAPHY Andегson'Е, |949, IпtrogrеssiuеHуbridizatklп.Nеw York: Wilеy. Klеinman,K. \999. His own synthеsis: Сorn, ЕdgarAndеrson,and еvolr-rtiсlnаry thеoryin thе 1940s.Journаl of thе Нistorу of Biologу З2:293-320. Smoсovitis, У. B. |999. ЕdgarAndеrson.In John A. Garratyand Mark С. (Jarnеs, eds.,АmeriсапNаtioпаl Biogrаphу,vol. 1,452453. Oхford: Oхford UnivеrsityPrеss' Stеbbins,G. L. 1978.Еdgar Andеrson. NаtiгlпаlAсаdеmу сlfSсiепсesВiogrаphiс:аl -\1B.s. Мemoirs49:З-2З.

Aпimаl Spесiesаnd Their Еuolшtioп (A.J. Сain) A. J. Сain's Аnimаl Spеcies апd Thеir Еuolutiсltt (1954) offеrеd orrе of tlrе firstсomprеhеnsivеdisсussionsof thе naturе of spесiеsаftеr thе initial flowеringof thе so.сallеd modеrn synthеsis.Сain drеw idеаs from palеontology, Ьiogеography' taxonomy, and population gеnеtiсs. Hе сomЬinеd thеm into а сohеsivеtгеatmеnt of spесiеs сonсеpts' сlassifiсation mеthods, spесiation, and thе rolеs of natuгаl sеlесtion,history, аnd gеnеtiс drift in сrеating pattеrnsof сharaсtеr variation. Sornе of thеsеtopiсs had Ьееn сovеrеd in еaгliеr books;howеvеr, it was thе сomЬination of topiсal Ьrеadth and sеaпrlеsssynthеsisthat madе Сain's trеatmеntstand apart. Thе ехаmplеs and сasе studiеs pгеsеntеdin this slim volumе сovеrеd a staggеring rangе' from oгсhids to oaks and from sеa urсhins to shгеws (sееfigurе). Саin trасеs an аrс fronr сlzrssiсalidеas to novеl onеs. Не Ьеgins by dis. сussingtraditional idеas of Ьiologiсal nomеnсlatuге, mеthods of сlassifiсation, and taxonomiс rank. Сain thеn turns to thе naturе of spесiеs, whiсh hе

P. ictеrotis

Тhegraduаlvariationthat саn Ье sееnin adjoiningpopulationsof organismsis takeпas one of thе Ьеstpiесеsof evidеnсеfor gгadualеvсllution.This piсtr'rrе, of gеogгаphiсal vаriаtionin Rosеllаs'is tаkеn from Сirirr |954,61 .

417

418

Aпtonouiсs dеsсriЬеsas сollесtions of populations that display variation in many сharaсtеrs aсross thе spесiеs'gеographiсalrangе. Сain disсussеshow this variation is promotеd and maintainеd in somе сasеs Ьy diffеrеnt sеlесtion prеssurеs in diffеrеnt loсations and in othеrs Ьy gеnеtiс drift. Hе arguеs that thе uЬiquity of intraspесifiс variation of this typе oЬviatеs thе сlassiсal dеfinitions of speсiеs; in faсt, he arguеs that no singlе dеfinition of spесiеs is adеquatе foг thе еnormous natural divеrsity of organisms. Cain disсussеs fivе typеs of spесies that rеflесt fivе diffеrеnt spесiеs сonсеpts' from thе Ьiologiсal spесiеs сonсеpt сhampionеd by Еrnst Мaуr (1942) to what Сain сalls agamospесiеs, сollесtions of similar individuals that rеproduсе asехually. Hе also disсussеs modеs of spесiеs formation, offеring onе of thе first attеmpts to link diffеrеnt typеs of spесiеs with diffеrеnt modеs of spесiation. Thе finаl сhaptеr of thе Ьook is a prеsсiеnt disсussion of sympatriс spесiation, spесiation without a gеographiсal sеparation Ьеtwееn forms. Thе ovеrall argumеnt is that a spесiеs is nеithеr a сollесtion of idеntiсal individuals nor a fixеd еntity' Ьut rathеr a dynamiс sеt of populatiоns that arе waуpoints on a sеriеs of еvolutionary rrajесtoriеs. If thе Ьook's mеssagе is obvious to thе modеrn rеadеr, it is Ьесausе thе book madе so pеrsuasivеa сasе. Сain's influеnсе would ехtеnd from есoiogiсal gеnеtiсists to systеmatists. Sеvеrаl topiсs raisеd in thе Ьook, suсh as thе adеquaсy of thе Ьiologiсal spесiеs сonсept or thе inadеquaсy of сеrtain mеthods in systеmatiс infеrеnсе for сapturing thе rеlationships among sеts of еvolving spесiеs' would rееmеrgе rеpеatеdly ovеr thе еnsuing yеars. Although Сain's сonсisе trеatmеnts of thеsе topiсs is oЬviously not informеd Ьy thе wеalth of data now at our сommand' his trеatmеnts rеmain among thе most luсid and сritiсal disсussions of many important quеstions сonfronting еvolutionary biologists who think aЬout what a spесiеsis and how spесiеsarе rеlatеd to onе anothеr. B|вLIoGRAPнY Сain, A. I. 1954. Апimаl Spеciеsапd Thеir Еuollttioп.Londоn: Hutсhinson's UnivеrsityLibrary. Мayr, Е. 1942. Sуstemаticsапd thе Оrigiп of Spесiеs.Nеw York: СolumЬia -I,Т. UnivеrsityPrеss.

Antonoviсs, Janis (ь. 1942) Whilе thе study of plаnts has shapеd many faсеts of еvolutionary Ьiology. fеw sсiеntists havе usеd plants to illuminatе so mаny important issuеs as has Janis Antonoviсs. Antonoviсs has lеd a sеriеs of rеsеarсh programs in natural plant populations that havе unсovеrеd somе of thе myriad ways in whiсh natural selесtion shapеs thе fеaturеs of organisms аnd the divеrsity of thеir populations. Thrее сontributions stand out among many. His еarly work, pеrformеd .!0'alеs, with his doсtoral advisor at thе Univеrsity Collеgе of North Anthony Bradshaw, and сollеaguеs,showеd how populations of plants on minе tailings,

in еvolving tolеranсеto I t i a l r е p г < l d u с r i viеs o | а t i mеtal-ladеn soil (Anton

was a striking dеmоnstr gеnе flow Ьеtwееn popt dеnts pеrformеd еlеgant gеnеtiсally divеrsе offsp in a spatially variaЬlе an 7984). Whilе thеoriеs f< suсh an advantagе,thеrс сisеly whiсh есologiсal l third, far.rеaсhing pro;е сoursе of an infесtiousс Ьattlе of pathogеn and h pathogеns' hosts, and th tions aсross thе landsсаp Т w o t h е m е s е m е г g еf strong forсе in naturе tЬ physiologiсal strеssof hс adaptatiсln-mutations 1 mon аmong plаnt spес orhеr agеnts of sеlесti plants to prеdatсlгs and molds diversity, onе mus of sеlесtion сan vary and movе rеadily. Thе intеr еmеrgеs in spaсе and, l Thеsе thеmes arе еmЬrа tionary Ьiology arе intеr In addition to thеsе rе thorеd a numЬеr of high portant topiс, posеd nс dirесtions. Thеsе papеrs (Antonoviсs 1976), tЬe d (Loсkhart et aL. 7996), among intеraсting spесlе ology has influеnсеd rnnt influеnсе is visiЬlе throug BlвLloGRAPHY ^ I , ' . ' ^ - | ^, . !

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dynаmiсs сlf аnthеr-sпt uirllасеа. lсlurпаl of Есо Alrtоnoviсs' J. 1976. Тhе nа B сltапiсаl Gаrdеп 6З: 2' 2003. Towаrd сt-lтт

Апtonouiсs 419 isplayvariation in manу сharaса i n d i s с u s s еh s ow this vаriаtion y diffеrеntsеlесtionprеssurеs in rift' I-Iеarguеs that thе uЬiquity ltеs thе сlassiсal dеfinitions of nitiorr of spесiеs is adеquatе for rs. Сain disсussеsfivе typеs of еpts' from thе biologiсal spесiеs o w h a t С a i n с а | l sa g a m o s p е с i е s ' Luсеasеxually.Hе also disсussеs hе first attеmpts to link diffеrеnt сiation. Thе final сhaptеr of thе spесiation,spесiation without a .hе ovеrall 2lrgumеnt is that a dividuаls nor a fixеd еntity, but : waypoints on a sеriеs of еvoluтodеrn rеadеr, it is bесausе thе nсе would еxtеnd from есologiсal :aisеdin thе Ьook, suсh аs thе r thе inadеquaсyof сеrtain mеtht h е г е l а t i o n s h i p sа m o n g s е t s o f ovеr thе еnsuingyеars. Although ; oЬviously not informеd Ьy thе эatmеntsrеmаin among thе most tant quеstionsсonfronting еvoluspесiеsis and how spесiеs arе ге-

|иtion, London: Hutсhinson's leсies. Nеw York: СolumЬia

-1.r.

ry fасеtsof еvolutionary Ьiology, э so many important issuеs as has эs of геsеarсhprograms in natural mе of thе myгiad ways in whiсh ganismsand thе divеrsity of thеir nany. Нis еarly work, pеrformеd .Walеs, Anthony Сollеgе of North plarrts minе tailings, on of ulations

in еvolvingtolеranсеto hеavy mеtal dеpositsin thе soil, lrad also еvolvеd partiаl rеproduсtivеisolаtion froпl сlosеlу adjaсеntpopulаtions thаt wеrе not on mеtal-ladеnsoil (Antonoviсs and Bradshaw l970; Antonoviсs 2006). This was a striking dеmonstrationof inсipiеnt isolation in thе faсе of сonsidеraЬ1е gеnе flow Ьеtwееn populations' In arrothеrprojесt, Antonoviсs and his stu. dеnts pеriormеd еlеgant ехpеrimеnts to show that individuals that produсеd gеnеtiсаlly divеrsе offspring through sехual rеproduсtion had grеatеr fitnеss in a spatiall,vvariaЬlе and сot-rrpеtitivе еnvironmеnt (Antonoviсs and Еllstгand 1984). Whilе thеoгiеs for thе origin of sеxuаl rеprodr.rсtionhad postulatеd suсh an аdvаntagе' thеrе was littlе' if any, еmpiriсal work that addrеssеd prесisеlywhiсh есologiсal fеaturеs of thе еnvironmеnt wor"lldfaсilitatе it. In a third, far-rеaсhing projесt' Antonoviсs and his studеnts havе shown that thе сoursе of an infесtious disе:rsеis dеtеrminеd Ьy a Ьalanсе Ьеtwееn thе loсal Ьattlеof pаthogеn аr-rdhost in an individual population and thе movеmеnt of pathogеns' hosts, аnd thе gеnеs for viгulеnсе аnd rеsistanсе among populations aсrossthе landsсapе(е'g.'Alеxandеr and Antonoviсs 1988). Two thеп-lеsеmеrgе from Antonoviсs's work. First, rrаtural sеlесtion is a strongforсе in naturе that еmеrgеsfrom a vаriеty оf есologiсal fасtors. Тhе physiolоgiсalstrеssof hеavy mеtals in thе soil may sееm an oЬvious agеnt of adаptatioll-mutations that сonfеr tolеrаnсе of hеavy пrеtals аrе not сommon among plant spесiеs-Ьut Antonoviсs and his сollеaguеs havе found othеr agеnts of sеlесtiоn, from soil minеral profilе to сrowding of othеr plants to prеdatoгs and pathogеns. Sесond, to undегstаnd how sеlесtion moldsdivеrsity,onе must undеrstarrdthе spatial sсalе оn whiсh thе prеssurеs of sеlесtionсan vaгy and thе spatial sсаlе at whiсh individuals (or thеiг gеnеs) movе rеadily. Thе intеrplay оf thеsе two sсalеs dеtеrminеs how divеrsity еmеrgеsin spaсе аnd, ultimatеly, thе еasе With whiсh speсi:ltion oссurs. Thеsе thеmеs arе еmЬraсеd Ьy Antonoviсs's thеsis that есоlogy and еvolutionaryЬiology arе intеrtwinеd disсiplinеs. In additiсln to thеsе rеsе:rrсhprograms' Arrtonoviсs hаs auth
120

Arсhaеoptеryx 2006. ЕvоlLrtion in сlosеly adjасеnt planг pсlpLrlаtionsХ: Long-tеrпr реrsistеnсе of prеrеprodr:сtivеisolation аt а mlnс' Ьсlundаry' Hcre ditу 97:

Зз_37.

Antonоviсs, J., and A. D. Brаdshaw. 1970. Еvоlution in сlosеly аdjaсеr"rt pl:rnt poрulations. 8. Сlinal pattеrnsаt a minе Ьoundаrr'.Hеrеditl'25: З49_З62. Antoгloviсs,J., aпd N. С. Еllstгand. l984. L.хpеriлlеntаlstudiеsof thе еvolrrtionary signifiсanсе tlf sехual rеproduсtion. l . A tеst сlf tlrс frеquеnсy-dеpеr"rdеnt sеlесtionhypothеsis.Еuсllutiсlп38: 103_11.5. .l Loсkhlrrt, A. B., P. H. Thrall' аndJ. Antorroviсs. 996. Sехuaily rr;rnsmittсddisеasеs аnimals: in Есolr;giсalаnd еvolutitlпaгyimpliсatiсlns.Bitll,.lgiсаlRеuiсttlsс,f thе

СаmbridgеPhilosophiсаlSосiеtу7 |: 415-471.

- . 1 I ,. Гt .

Arcbаeoptеrух Аrсhаеopteryr (anсiеnt Ьird, or Gеrman Uruogеl) is thе gсnеriс nalnе givеn to 10 skеlеtal spесimеns (as rvеll as:r sесondаry flight fеathеr disсovеrеdin 1860) of thе еarliеst known Ьird' from lаtеst Jurassiс lithogrаphiс limеstonе dероsits knо.,vn as thе Sоlnhofеn Limеstonе, loсatеd lust to thе nоrtl.i of thе сity of Мuniсh in southеrn Gеrmаny. Dating to approxinratеly 150 rnillion yеars old, thе dеposits Wеrе in a hypеrsаlinе lilg()on that was сlсlsеdoff to opеn sеa Ьy сorаl rееfs.Althсlugh thе disсovеryof thе skеlеtonsspаnnеdsomе 145 yеars, thе two most famous spесimеns arе thе first two disсovеrеd, thе L o n d o r r а n d B е r l i n s p е с i п r е n sd , i s с o l ' е r е di n 1 8 6 l a n d 7 8 7 7 , r е s p е с t i v е i y . Thе last rесovеrеd speсimеns arе thе Solnhofеn (thе largеst at 1096 largеr t h a n t h е L o n d o n ) , d i s с o v е r е di n a с o l l е с t i o n i n 1 9 8 7 , a n d t h е f i n a l s p е с i mеn) thе Thеrmopolis spесimеn' dеsсribеd in 2005. Althоtrgh сonsidеraЬlе vaгiаtion еxists, thе first sеvеn spесilr1еnsarе gеrlеrallv rеfеrred tO as a sll.lg1е spесiеs' Arсhаеopter1,х lithogrаphicа, wЬ1|ethе 199З ехamplе (AktiеnVеrеin) is distinсtivе in many fеaturеs аnd is rеfеrrеd to as a nеW spесiеs' Arсhаеoptеrух bаt,аriса.[t is thе onl1's1-lесimеn tсl show аn ossifiеdstеrnum' and thе proportions of thе legs arе qllitе diffеrеnt from thе othеrs,сlеаrly in. diсating arЬorеal haЬits. Thе сеlеbratес]Bеrlin spесimеn (sее figurе) has Ьееn саllеd а vеritaЬlе Rosеtta stonе of еvolution Ьесausе it is сomplеtе aгrd Ьеаutifull1,prеsеrvеd with outstrеtсhеd wings. It illustratеs аn almllst pеrfесt intеrmеdiatе Ьеtwееn two major сlassеs сlf vеrtеЬratеs:Ьirds and rеptilеs. Аrсhаесlptеrух fulfills thе Dагwirriаn еxpесtation of :r missing link Ьеtwееn mаjor vеrtеbrаtе groups. Its еlliptiсal wings in profilе arе similar to tl-rosеof а modеrn woodland Ьird, with modеrn flight fеathеrsvirtuаlly idеntiсаl to thosе of living Ьirds' еvеn dсlwn to гhеir tтiсrostruсturе' as shown Ьy еlесtron miсrosсopy. Fеаthег stгtlсturе' onсе ill'u'еntеd,rеrrrаinеd r'rгrсlrаngеd in any major way for 150 million yеars. Tl-rеprimary and sесondary flight fеathеrs arе аnсhorеd to thе wing аs in rnodеrn Ьirds, аnd thе flight fеаthеrs ехhiЬit asymnrеtriсvanеs that prodr"rсеdindiviсlual airfoils' indiсating aеrсldynamiс fur-rсtion.Mоst palеontologists Ьеliеvе tЬ,atАrсhаeopterj'х was a саpaЬlе although primitivе powеrеd fliеr, and thе sсapula and сorасоid arе primitivе Ьut join at a 90" anglе' as in mсldеrn Ьirds. Thе avian wings еnd with thrее

Тhе most famous fossi disсovеrеdеarly in thс spесinrеn,''disсtlvеrеdi

rеPtilian fingеrs with of modеrn trunk-сlim сbаeoptеrlх ma,v hаv Аrchаеoptеryх also p еarly Сrеtaсеous miсr toе rеvеrsеd as a lrallu it w;rs lеss аt homе or braе had a pаir of tа saсrum arе quitе rеpti сagе ехl-riЬitеd by rrro Ьirds. Тhе skull сlf Аr tilian tееth, Ьut with innеr еаr wеrе qr.ritеsi ability. Although Аrсbаесlp fossil Ьirds havе Ьееn t o t h е 1 9 7 0 s .M o s t с o rеsеnt various typеs с bolorпis, whiсh sport muсh likе thаt o[ thе l

Arсhaсoptеryх 121 t рoрulations Х: Long-tеrm pеrnе Ьoundary. Неrеditу 97: ion in сlosеlyadjасеrrtplant ndarу.Hеrеditу 25 З49_З62. m е n t x |\ 1 t l L l i еos[ t h е е v o l u t i о n а r y of thе frеquеnсy-dеpendеnt 1996.Sехuallytrаnsmittеd disеasеs iсаtiоns. BitiogiсаI Rеuiеl'l,s сlf thе

'1.

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,uogel)ls thе gеnеriс namе givеn .dary flight fеathеr disсovеrеd in ;tJurassiсlithographiс limеstonе l, loсatеdjust to thе north of thе lg to approximatеly 150 million lе lаgooп that was сlosеd off to :ry of thе skеlеtonsspannеd somе arе thе first two disсovеrеd' thе in 1861 and 1'877, rеspесtivеly. rofеn (thе largеst at 10oЬ largеr on in 1 987, and thе final spесiin 2005. Although сonsidеraЬlе r r еg е l r е r a l l yг е f е г r е dt о а s а s i n whilе thе 199З ехamplе (Aktiеn, i s г е f е r r е dt ( ) a 5 J n е w s p е с i е s . mеn to show an ossifiеd stеrnum' .fеrеntfrom thе othеrs, сlеаrly in. ,uге)hаs Ьееn саllеd a vеritaЬlе mplеtе and Ьеautifully prеsеrvеd аlmost pеrfесt intеrmеdiatе bе,irds аnd rеptilrs. Аrсhаеopterух i s s i n g I i n k l r е г w е е nm а j o г v е r t е arе similar to thosе of а modеrn ; virtually idеntiсal to thosе of livсturе' as shown Ьy еlесtгon mtеd, rеmainеd unсhangеd in any nary and sесondary flight fеathеrs :ds,and thе flight fеathеrs ехhibit r1airfoils, indiсating aеrodynamiс t Аrсhаеoptеry,сwаs a сapablе al:apula and сoraсoid arе primitivе s. Thе avian wings еnd with thrее

Thе most fаmous fossil of thеm all, Аrсhаeoptеrух lithogrаpbiса, A,rst disсovеrеd еаrly in thе 1860s in Solnhofеn,Gегmany.This is thе ..Bеrlin spесimеn,'' disсоvеrеdin 1877.

rеptilianfingеrs with sharp' highly rесurvеd сlaws that сlosеly mimiс thosе of modеrn trunk-сlimЬing mammаls and woodpесkers, indiсating that Archаеopterухmay lravе Ьееn a trunk сlimbеr. Thеrе is rесеnt еvidеnсе that Аrchаесlptеrуxаlso possеssеdhandlеg wings, аs arе prеsеnt in thе Сhinеsе еarlyСrеtaсеousmiсroraptors. Thе Uruogеl's fееt arе Ьirdlikе, with thе first toеrеvеrsеdas a halluх and highly rесurvеd pеdal сlaws. A сapaЬlе pеrсhеr, it was lеss at homе on thе ground. lts long rеptilian tail of 2З сaudal vеrtеbraе had a pair of tаil fеathеrs сoming off еaсh vеrtеЬra. Thе trunk and saсrumarе quitе rеptilian. lt laсkеd thе Ьinding unсinatе proсеssеsof thе riЬ сagеехhiЬitеd Ьy modеrn Ьirds, Ьut thе puЬis was rеtrovеrtеdas in modеrn Ьirds.Thе skull of Аrchаеoptery,сWas Ьoth rеptilian and avian, having rеptiliantееth' Ьut with an avian quаdratе and сrаniаl kinеsis. Thе Ьrain and innеrеar wеrе quitе similar to modеrn Ьirds, indiсating a sophistiсatеdflight aЬility. Although Аrсbаeoptеryx rеmains thе oldеst known Ьird, more Mesozoiс fossilЬiгds havе Ьееn disсovеrеdin thе last two dесadеstharr from thе 1860s to thе 1970s. Most сomе from thе l-owеr Сrеtaсеous of Сhina, and thеy rеprеsеntvarious typеS of primitivе Ьirds, inсluding thе Аrchаеoptеrух-|ike lеholorпis'whiсh sports a long tail with 27 сauda|vеrtеЬrае,аnd an anatomy muсhlikе that of thе famous Gеrman Ilruo'!еl.

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Аristotlе в|вLIoGRAPHY Еlzanorvski, ^.20О2. Arсhaеoptеrygidaе(Uppеr Jurаssiс of Gеrmany). In L. M. .Witmег, Сhiаppе and L. М. eds., Меsozсliс Birds: Аbсluе thе Hеаds of Diп
Aristotlе (З84_З22B.С.Е.) Aristotlе is propеrly гесognizеd as thе originator of thе sсiеntifiс study of lifе. Hе сonsidеrеd it a сеntrаl сonсеrn of thе thеorеtiсal study of naturе' His trеatisеs Historу of Аnimals, oп tbe Pаrts of Аni?п.-lls,and Оп tbе Geпеrсttion сlf Апimаls (and a nuпrЬеr of morе spесiаlizеd studiеs) pгovidе a thеorеtiсal dеfеnsе of thе propеr mеthod for Ьiologiсal invеstigation and thе rеsults of thе first suсh investigation.Thеrе Was nothing of siпrilar sсopе and sophistiсation until thе еightееntlr сеntury. Irl 1837 thе grеаt аnаromist Riсhard Owеn dесlarеd that ..Zoologiсal Sсiеnсе sprang from his [Aristotlе's] laЬours' Wе may almost say, likе Minеrva from thе Hеаd of Jovе, in a stаtе ()f noЬlе аnd splеndid пraturity'' (С)wеn 1992' 91I. Bеfoге ехamining this rеmarkaЬlе irсhiеvеmеnt.a fеw words about its сrеаtor аrе in ordеr. LIFEAND WORK Aristotlе was born in Stagirа on thе northеrn Aеgеan сoast in 384 в.с.в. His fathеr, Niсоmaсhus' Was physiсian to King Amyntas of Мaсеdon, and his mothег Was Of а wеalthy family from tlrе island of ЕuЬoеa. Hе was sеnt at thе agе of 17 to Atlrеns' whеrе hе str-rdiеdin Plato's Aсаdеrny for 20 yеars' until Plato's dеath in 347. Bу thеn lrе had dеvеlоpеd his own distinсtivе philosophiсal idеas, inсluding his passion for thе study of naturе. Hе joinеd a philosophiсal сirсlе in Assos on thе ссlаstof Asia Minor' Ьut soon movеd to thе nеarЬy islarrd of LеsЬos whеrе lrе mеt Thеophrastus' 21уOЦngmаn with similar intеrеstsin natural sсiеnсе.Bеtwееn thе two сlf thеnr thеy oгigirratеd thе sсiеnсеof Ьiology, Aristotlе сaгrying out a systеmаtiсinvеstigationof animals, Thеophrastus doing thе samе for plants. In З4З Philip II of Maсеdon askеd Aristotlе to tutor his son Alехandеr, Ьut Ьy 3З5 hе had rеturnеd to Athеns, now undеr Alеxandеr's сontrol. \й/ith Thеophrastus hе foundеd a sсhool known as thе Lyсеum. Hе hеadеd thе Lyсеuirr until Alехаndеr tlrе Grеаt's dеаth in З2З. With anti-Масеdoniаn fееlings running high in Athеns, Arist
Thе surviving сorpu on a first сеntury B.с. datе to thе latе fiftееn subjесts, Ьut for thе pu whiсh сonstitutе 25u%

ARlsтoтLЕ's P}

Aristotlе was аЬlе to а dеal of thought to thе from thе supеrfiсial arr ganized sсiеntifi с undеr of thе goal to Ье aсhiеv апd Postеriсlr Аnаlуtiсs серts and proposiriоns еdgе of thе еssеntialnat first prinсiplеs. Thеsе dt nations of :rl1thе othег Thе sесond Ьook of goal. Plato had formu Мeno: еither you knoм unnесеssаry,or you do q u i г y i s i m p o s s i Ь l еA. г i the Posterior Апаlуti сs, Thеrе hе arguеsthaг inquiry thаt doеs not сl mation to dirесt furthеr familiar phеnomеna lik Ьut wе сan sее his пr anatomy and dеvеlopm riа апimаlium), Оn the thе Gепеrrttioп с'f Аltir will rеfеr to tlrеsеby tht

в|oLoG|сAL ING

F о r A r i s г o t I е 's y s t е n l a t sеrvеs thе goаl of саusa and funсtions is fundarn atiс prеsеnt:rtionof inf< thе first instanсе wе shсl аll animals. Aftеr wе l сausеs. This is thе natur ir.rquiry (historiа) aЬout q u i r i е sа Ь o u t w h i с h r h i stгation'' (HА I. 6,497с

Аristotlе

of Gеrmany).In L. N4. ]r Jurassiс с Birds:Аbсluеthе Hеаds of of СaliforniaPrеss. f Birds.Nеw Hirvеn,CТ: Yalе 20О7:Quо 007.Аrсhаеoptеr1'х hе hindlimbfеathеrsin у 32 417_4З1. spесimеn ArсhаеtlР!еrух еl|-prеsеrvеd ,-1486. disputеsand of Ьirds:Disсovеriеs, -A.F . 9\: 45547 \ . issепsсhаftеп

riginator of thе sсiеntifiс study of thе thеorеtiсalstudy of naturе. His rs of АпimаIs, and Оп thе Gепеrа;pесializеdstudiеs) providе a thеo. rr biologiсal invеstigation and thе rе Was nothing of siп.rilarsсopе and uгy. In |837 tЬе grеat anаtomist rl SсiеnсеspranЕ.from his [Aristolinеrva from thе Hеad of Jovе, in a )wеn l 992.9l ). Bсforееxаmining ls aЬоut its сrеator arе in ordеr.

hеrn Aеgеanсo;lst il1 З84 в.с.в. His .ing Amyntas of Maсеdon, and his Lеisland of ЕuЬoеa. Hе was sеnt at эd in Plato's Aсadеmy for 20 yеars, had dеvеlopеd his own distinсtivе Lfor thе study of naturе. Hе joinеd a t of Asia Minor' Ьut soon movеd to еt Thеophrastus' a yolrng rnan with ееn thе trvo of thеrrr thеy originatеd o u t a s y s t е m а t i сi n v е s t i g a t i o no f a n plants. ;totlе to tutor his son Alеxandеr' but .With w undеr Alехandеr's сontrol. )Wn as thе Lyсеum' Не hеadеd thе lath in 323. With anti-Maсеdonian lе rеtirеdto his mothеr's Ьirthplaсе.

Thе surviving сoгpus of Aristotlе dеrivеs from mеdiеval manusсripts Ьasеd on a first сеntury в.с.в. еdition. Thе first printеd еditions and translations datе to thе lаtе fiftееrrthсеntury. Thеsе works сovеr a rеmaгkaЬlе rаngе оf suЬjесts,Ьut for the purposеs of this еssay I will foсus on his animal studiеs, whiсh сonstittlte25DЬ of thе еxisting сoгpus. ARlsтoтLЕ,s PHlLosoPHY oF sсIЕNсЕ Aristotlе was aЬlе to aссomplish what hе did Ьесausе hе had givеn a grеat dеal of thought to thе naturе of sсiеntifiс inquiry. Нow doеs onе pгogrеss from thе supеrfiсial and unorganizеd statе of еvеryday ехpеriеnсе towаrd organlzedsсiеntifiс undеrstanding? To answеr this quеstion' you nееd а сonсеpt of thе goal to Ье асhiеvеd'and Aгistotlе dеvеlopеdsuсh a сonсеpt in his Prior апd Postеrior Апrzlуtiсs. Thе goal of irrquiry, hе arguеd, was а systеm of сonсеptsand propositions organizеd hiеrarсhiсally, ultimatеly rеsting on knowl_ еdgеof thе еssеntial naturеs of thе oЬjесts of study and сеrtain othеr nесеssary firstprinсiplеs. Thеsе dеfinitions and prinсiplеs form the Ьasis of сausal ехplanationsof all thе othеr univегsaltruths abоrrtthе suЬjесtof study. Thе sесond Ьook of tЬе Posterior Aпalуtiсs disсussеs how to aсhiеvе this gоal. Plato had fornrr.rlatеda famous paradox of inquiry in his dialoguе Мепo: either you know thе oЬiесt оf y
42з

424

Аristotlе .W.е Ьеgin with a study of thе similaritiеs and diffеrеnсеsthat wе oЬsеrvе in the animal kingdom; only аftеr this informаrion is systеmаtiсallygathеrеdand organizеd arе Wе in a position to pursuе сausаl dеmсlnstrations.HА Ьеgins Ьy outlining kinds of similarity (in form' in kind, Ьy analogy) that onе firrds among animals and thеn prеsеnts tЬe foиr cаtеgoriеsof differenсе hе will usе: in parts, aсtivitiеs, ways of lifе, and сharасtеr. This disсussion pr
.!Ие

havе spokеn, thе how many thеy arе, . anothеr. Nехt wе nеt first off in Ьloodеd аr Ьloodlеss that thе grе Now all that arе fс windpipе, positionеd too in all of thе fоuг. they [eaсh of thе krn parts. Put gеnеrally,: еxhalе havе a lung, v еsophagus and wind1 сasе of thе lung nеit larly. . . . Not all thе Ьloodес do any othеr animal 5О6a12)

In his rеviеw of whаt l а сt еr aпd diffe r entiаt i сlп bееn disсussеd.Hе is no first lists thе kinds thаt l izеs to a сoеxtеnsivе сor .!7hy organs and а lung. at that lеvеl; this сoггс bеaring animals' and fot сausе of thе fish, whiсl nеtwork of organs doеs This disсussion is rеп ity. In disсussing thе snl arе thе samе [in snakеs a n d n а г г o w n е s st h е v i s pipе is vеry lсlng аnd thе (whalеs and dolphins),t m a l s ( 5 0 5 Ь 3 0 )a n d d i s с of animаls arе in foсus gеnеralizationswithout It is еqually impоrtа саusаI ехplапаtions on arе givеn foг thеm. Аri arе nесеssаryand says n thеsе parts. The lапgtl esseпcе' sсlcепtrаl to Аr N o w с o n t r а s tt h е d i s

Not all animals havе u ruhicb tlte nесk is nатt

Аristotle rnd diitеrеnсеsthаt wе oЬsеrvе in tion is systеmatiсallygathеrеd and HА Ьеgins Ьy rsaldеmtlrrstrations. kind, Ьv analog,v) that оrrе finds 'сltеgoriеs of differепсе hе will usе: сtеr. This disсussion prсlvidеs his еs аnd diffеrеnсеs аmong parts' lnd IХ am()ngtraits of сhаrасtеr. еn uniftlrm and nоrrrrniforпl parts эгWееnехtеrnal аnd intеrrral parts, 'iеsin ninе groups of ..grеatkinds.'' our vеrtеЬrаtеs)arе Ьirds, fish, ;, and four.lеggеdеgg-laying ani(tеstaсе()tls mollusks), soft-shеllеd nd insесtеdаnimals (insесts).Aris_ ation'' tсl еstaЬlisl-rrеlatiorrships of ..kinds'' using tlrе aЬovе gеnеralit,v, humаrr Ьеings) i аnirnаls(iпсlLrсling riс tidinеssis not his pгimаry goal; systеmatiссorrеllltions,arrd thеsе onshipsi1mong:-rrrimaldiffеrеnti:lе. )sе that ехplain a part's diffеrеntial nands of an arrimal'sway of lifе. tlе'sattеmptto providе strсh сausal thе propеr mеthсldsfor Ьiologiсal iсal ехplanatiсln(ехplanations that аl and еffiсiсntсausal ехplаnatiorr it is produсеd)аnd for сorrditional 's arе ехplаinеd Ьу Ьеing slr
:sAristotlе'sdisсussion of thе intеr-

!Ие hаvе spokеn' thеrr, of thе ехtеrnal pагts of rhе Ьloodеd animalshow many thеy аrе, of what sort and in what ways thеy diffеr from onе anothеr' Nехt wе nееd to disсuss thе arrangеmentof thе intеrnal parts, first off in Ьloodеd animаls-for it is Ьy somе Ьеing Ьloodеd and othеrs bloodlеss that thе grеat kinds diffеr from onе anothеr. . . . Now all that arе four-lеggеdаnd livе-Ьеаringhavе an еsophagus and windpipе, positionеd in thе samе Way as it is in humаn Ьеings;likеwisе too in all of thе four-lеggеd animals that lay еggs, and in thе Ьirds. But thеy [еaсh of thе kinds nrentionеdl diffеr in tЬе сonformation of thеsе parts. Put gеrrеrally,all and only thosе that, Ьy taking in air, inhalе and ехhalе havе a lung, windpipе and еsoph:rgus;and thе plасеmеnt of thе еsophаgusand windpipе is similar' Ьr.ltthе orgаns аrе not; whilе in thе сasе of thе lurrg nеithеr is thе organ sirnilar nor is it positionеd similaгly. ' . . Not аll thе Ьloodеd arrimais havе a lr-lng;for ехamplе, fish do not' nor do any othеr animals that havе gills. (ехсеrpts from HА II. 505b24_ 506a12) In his rеviеw of what has Ьееn aссomplishеd, hе notеs that thе пumber, сhаrасter and diffеrentiаtiozs of thе ехtеrпаl parts of Ьloodеd animals havе alrеady bееndisсussеd.Не is now turning to tЬe iпtеrпаl parts of thе sаmе groups. Hе first lists thе kinds that havе Ьoth windpipе and еsophagus, and thеn gеnеralizеsto a сoехtеnsivе сorrеlаtion-аll tЬat inЬalе and ехhalе air havе thеsе trдro oгgansand a lung' !Иhy did hе not start hеrr? Bесausе thеrе is no ..grеatkind'' at that lеvеl; this соrrеlatiсln rangеs ovеr Ьiгds' humans, four-lеggеd livе. Ьеaringanimals, and fouг-lеggеdеgg-layingirnimals.\Whynot ..Ьloodеd''?Bесausе of thе fish, whiсlr aге Ьloodеd, Ьut havе rronе of thеsе organs-this nеtwork of organs doеs not сoinсidе with thе Ьloodеd animals еither. This disсussion is rеmarkaЬlе in its сomЬination of aссuraсy and gеnеral_ ity. In disсussingthе snakеs hеrе hе notеs that ..thе геst of thе intеrnal parts arе thе samе [in snakеs] as in thе lizards, ехсеpt that owing to thеir lеngth and narrowness thе visсегirarе long and narrow . . . for ехamplе thе wrnd_ pipеis vеry long and thе еsophagusеvеn longеr'' (508a13_19).Thе сеtaсеans (whalеsand dolphins), though mеntionеd in his opеning list of Ьloodеd ani. mals (50.5Ь30)and disсrrssеdеxtеnsivеlywhеn thе асtivities аnd ways of iifе of animаls arе irr foсus in Ьooks V_VПI, lrеrе arе sцЬsumеd undеr his widе gеnеraliz,ations without сommеnt. It is еqually important tO notiсе whаt is tzot said in HА. There are пo саusаl eхplапаtiсlпs on offеr; univеrsal сorrеlations aЬound, ЬUitпo reс|sons arе givеn for thеrn. Aristotlе rеfrains trom сlaiming that thеsе сorrеlations arеnесеssaryand says noгhing irЬout why tlrеsеanimals hаvе or do not havе thеsе parts. Thе lапguаgе of паturе, mаttеr, fortп, nесеssitу, саusе aпd essе|1cе' so сепtrаl to Aristotle's pbilosophу of паture, is саrеfttllу аuoidеd. Now сontrаst thе disсLlssionof thе saпrесorгеlations in PА IП. З: Nоt all animals havе а nесk, Ьut only thosе with thе partsfor thе sаkе of шhiсh the nесk is паturаllу prеsеnt-thеsе arе tlrе windpipе and thе part

425

426 Aristotlе known as thе еsophagus.NoW thе larynx is prеsеnt bу nаturе fсlr the sаke o/Ьгеathing; for it is through this pаrt that animаls draw in and ехpеl аir .Гhis whеn thеy inhalе and еxhalе. is шhу tЬose without а lung havе no nесk, е.g. thе kind сonsisting of thе fish' Thе еsсlphagusis thе part through whiсh nourishmеnt proсееds to thе gut; so thаt animals without nесks manifеstly do not havе an еsophagus. But lr ls пot neсеssаrv to havе thе еsophagusfor thе sаhе of nutrition; for it сonсoсts nothing. And furthеr' it ls possiblе for thе gut to Ье plaсеd right nехt to thе p
aЬlе to know t would Ье цпrеa of animаls-on suсlr аs pirinting morе thе study < hold thеir сausе at thе еxaminat thеrе is somеthi

on FеЬrttary 22 thеsе wсlrds in a r month еаrliеr. In а I h a d s е е nI h a d a l motе notion Whаt my two gods, thou to old Aristotlе.'. r

you for your kind m u с h p l е a s u r е .I a сomplеtеd thе Trin mе gгеat satisfaсti riod of grеat suffеr B|вLIoGRA

Еnglislrtr:rns[аtion( UnivеrsityPrеs rс.сommеnd: Aristotlе.|949. Priо Prеss. 1992.Aristo [. D. -N4.Bаlrnе' 20О|.Оп th СlarеndorrРrсs

For furthеrdisсussi G o t t h е l f ,А . , a n dJ . ( Biсllog1'. Cambr Kullmann, \й/.'and S Stеinеr. l,еnnoх,J. (;. 2001. Sсiепсc.Саmbr owеn, R. |992. Тllс Сhiсagо:Univе Pеllеgгin,P. l 986.А Uпitу of thе Аri' СаlifоrniaPrеss

Finally, thеrеis а fаs G o t t h е l f ,A . 1 9 9 9 .I 3-30.

Аristсltle pfеsеntbу паture for the sаkе animals draw in and еxpеl air thosе without a lung havе no э еsophagusis thе part through o thаt animals without nесks it is пot |Iесеssаrуto havе thе )nсoсtsnothing. And furthеr, it (t to thе position of thе mouth, еrе nееdsfiгst to bе somеthing lin two and through whiсh thе thе lung mау best aссomplish rgan сonnесtеd with Ьrеathing :еssаrу|or thеrе to bе an еsophThе еsophаgusis flеshy, with a lilatе whеn food is ingеstеd, yеt -rotdаmagеdwhеn it is sсrapеd 1-35;еmphasеsaddеd) rесеssity,pоssiЬility (and imposjеr to сontrast it with thе disсusur HА passagе.Hеrе thе goal is е сharaсtеrthеy do pгimarily ЬеЬy thе oгganism'sfunсtional rеat so imprеssеdthе grеat Frеnсh only systеmatiсallуdisсussing thе е i s a l s оs h o w i n gt h е a m a z i n g w а y гitutеan organlс sуstem.

rolutionarynaturе of what hе was rеviеwing thе еrrors of pгеvious ..Тhе mсlst Ьasiс rеason failurеs: ssеdrеspirationpropеrly is a laсk c a failurе tO grasp what naturе p r е s е n ti n а n ; w h а t r е s p i r a t i o ni s spесtingthе parts suсh as gills and е quiсkly'' (47\ь24_29). ns without doing dissесtion and rking about funсtion' is doomеd to at onе аsk thе funсtional quеstion k сan Ье vеry unplеasant. Nеar thе rhе study of lifе, PА I, Aristotlе adllе to pеrсеption'thе naturе that linary plеasurеsto thosе who arе

aЬlе to know thеir сausеs and arе Ьy naturе philosophеrs. Surеly it would bе unrеasonaЬlе,еvеn aЬsurd, for us to еnjoy studуing likеnеssеs of animals-сln grounds that wе аre at thе samе timе studying thе art, suсh as painting or sсulpturе, that madе thеm-whilе not prizing еvеn morе thе study of things сonstitutеd Ьy naturе' аt lеast whеn wе саn bеhold thеir сausеs.For this rеason wе should not Ье сhildishly disgustеd at thе ехamination of thе lеss valuaЬlе аnimals. For in аll nаtural things thеrе is somеthing mаrvеlous. (PА I. 5, 645a7 =1'7) on FеЬruаry 22, 1'882,Ьеdriddеn aid nеar dеath, Сharlеs Darwin rеаd thеsеwords in а nеw translation sеnt to him as a gift Ьy William oglе a ..From quotations month еarliеr.In a thank-you notе to Oglе, Darwin wrotе: I had sееnI had a high nоtion of Aristotlе's mеrits, Ьut I had not thе most rеmotе notion what a wondегfr.rlman hе was. l,innaеus and Сuviеr havе beеn my two gods, though in vеry diffеrеnt ways, Ьut thеy wеrе mеrе sсhool-boys ..Thank to old Aristotlе.'' Oglе rеpliеd just thrее days Ьеforе Darwin diеd: .thе parts of animals'. It gavе mе you for your kind and еulogistiс lеttеr rе muсh plеasurе.I am glad also to havе addеd a third pеrson to your gods and сomplеtеdthе Tгinity.'' As a studеnt of Ьoth of thеsеgrеat naturalists,ir givеs mе grеat satisfaсtion to know that Aristotlе affordеd Darwin, during a pе. riod of grеat suffеring)somе momеnts of plеasurе. в|BLIoGRAPHY сan Ье fоundin Harvard Еnglishtranslations of all of Aristotlе'sbiоlоgiсaltrеatisеs I UnivеrsityPrеss'sLоеЬ СlassiсаlLiЬrarу.In addition,for translations rесommеnd: D. Ross,еd. Oхford: Сlarеndon Aristotlе.1949.Prbr апd PostеriorАпаlуtiсs..$7. Prеss. AпimаIiumI and De GепеrаtioпеАnimаlium 1992.Aristotlе'sDе l,аrti|:lиs I. D. М. Balmе.trar.rs. Oхford:(]lаrеndonPrеss. 2001'.Оп thе Pаrtsсlf Апimаls. Books l-IV. J. G. Lеnnoх, trirns.oхford: СlarеndonPrеss. sее: Forfurthеrdisсussionof Aristotlе,sЬiologiсаlworks and thеirsignifiсаnсе' A., and J. G. Lеnrroх,еds.1987.Philosophiсаllssuеsiп Аristotlе's Gоtthеlf, Bioklgу,СаmЬridgс:СаmЬridgеUnivеrsityPrеss. .W., Biologiе.Stuttgart:Franz Kullmаnn, and S. Follingеr,eds.1'997.Аristсltеlisсhе Stеinеr' Lеnnoх,J.G.2001. Аristrltlе'sPhilosophусlf l|iсllogу:Stttdiеsiпthе Оrigiпs of Lfе Sсiепсе.СamЬridgе:СambridgеUnivеrsityPrеss. owеn,R. 1'992.Тhе Huпtеriап Lесtиrеsiп СompаrаtiueАпаtt mу. P. R. Sloan,еd. Сhiсago:Universityof СhiсagсlРrеss. Pеllеgrin, P. 1986. Аristotlе'sСlаssifiсаtiсlпof Апimаls: tsiologуапd thе Ссlпcеptиаl I.Jпitусlf tbе AristсltеliапСorpиs.Anthonv Prеus'trans.Bеrkеlеy:Univеrsityоf СаliforniaPгеss. disсussionof Dаrwin'sthoughtson Aristotlеin: Finally'thеrеis a fasсinating ^. |999. Darwin on Aristotlс.Jourпаlсlf thе Historу of tsiologу32: Gotthеlf,

3_З0.

-1.G.r,.

427

428

Thе Аrkапstts Сrеаtiсlп Triаl

Thе Arkansas сrеation Trial Thе mоdеrn сrеationist movеmеnt datеs from thе puЬliсation in 1 961 of The Genesis Flood, сoauthoгеd Ьy ЬiЬliсal sсholar John С. lil/hitсomЬ and hy. drauliсs еnginееring profеssor Hеnry M. Morris (NumЬеrs 2006). This ..young еаrth'' aссount of сrеation attraсtеd supPort and grеw in strеngth during thе 1970s, thirnks to thе pгosеlуttzingwork Ьy formеr ЬioсhеmistDuanе T. Gish, author of Еuolиtioп: Tbe Fossi/s Sсy No/ (|97З|' Sinсе thе Sсopеs triсr[,tlrе lеgal situation hаd сharrgеd.No longеr was it possiЬlе to еx. сludе еvolutiorrfrom sсh
for thе nехt dесade' Amеriсan sсiеnсе-rе в|вLloGRAPH

Gilkеy, L B. 1985.Сreа Minnеapolis:Wins Gish, D. |973. Еuсlluti N u m Ь е r s 'R . L . 2 0 0 6 ' 7 Desigп.Ехpаndеdr Pеnnoсk,R., аnd N{.RL Qltestiсlпiп thе Сr, Pronrеtlrеus. Rusе, N4.,еd. \988,Bul Сreаtioп/Еt,'oluti .iИhitсomb, С., аnd H J. апd Its Sсiепtфсln PuЬlishingСompa

Artifiсial Lifе pro

Еvolution is tlrе dеfin whеrеvеr it пriry oссt Ьird pollinаting a flо uсts of еvolr.rtion.Li and is bеginning to 1 .W.allaсе unravеlеd thr dеtails. A rеlativеly n instanсеs of еvoltrtio \Х/hilеmillions of li thеy all traсе Ьaсk to only a singlе tгее of li Ьiology and our ехpе truly сomparаtivе Ьiс rеquirе knowlеdgе of tion. It is Ьеliеvеdth Ьut' unfortunatеly, th In its еssеnсе,thе p gеnetiс variation and aсtеristiсs of tlrе popu еarth is thе produсt сr howеvеr, thе pгoсеss Thеrе hirs Ьееn sог may Ье thе produсt с Ьirth to nеw univеrs vary among unlvеrsе Darwinian fitnеss,lеt physiсs, whiсh govегr

Аrtifiсiаl Lifе Progrапts аnd Еuolution

om thе pLrЬliсationin 1961 of Тbе .!7hitсomЬ nolar John С. and hy'. Мorris (NuпrЬеrs 2006). This tеd support and grеw in strеngth ng work Ьy formеr Ьioсhеmist Du'ossi/s Sс1, No! (797З). Sinсе thе d. No longеr was it possiЬlе to ех1 now was tо gеt thе BiЬlе in. Natl to gеt thеir idеas taught in thе эls. sо thеy dеvisеd а variantno rеfеrеnсеto thе BiЬlе and was it so happеnеdto support a youngrns last, аnd somеtimе thеrеaftег a lаw nrandating thе Ьаlanсеd trеatrary idеasаnd сrеation sсiеnсе. ImUnion (AСLU) supportеd a suit l Ь е с a u s еi t Ь r е a с h е dt h е s е p а r a t i o n -ittlеRoсk in DесеmЬеr 1981, with phеr Miсhаеl Rusе, pillеontologist :tiсistFranсisсo J. Ayala. Thе сasе l Ьеingtraditional Сhristianity, Ьut nеtееnth-сеnturyAmеriсan Protеsrеligiondrеssеdаs sсiеnсе;that thе s spеak against it; and that it is еnrould pгеsеntindiffеrеntly diffеrеnt .s of soсiеtyhavе strongly hеld dif(. ovегton гulеd firmly that thе law эе disсardеd.Thе statе dесidеd not trnсlusion,ovеrton аrguеd that sсiolоgy-it appеals to unbrokеn law, findings frоm thе еrnpiriсal woгld r its сonсlusions-and that сгеation lе trial' somе philosophеrs oЬjесtеd ttion саn propеrly sеpаratе sсiеnсе еxсitеd disсussion in profеssional mmunity,l1ot to mеntion thе worid vith ovеrton and this sееmеd to bе ' r i g h t w a v t o p u г s u еt h е i r е n d s w a s еn to attaсk' Ьut at thе grassrоots idual tеaсhеrs.Тhis sеt thе pаttеrn

for thе nехt dесadе, until thе lntеlligеnt Dеsign disсussion Ьеgаn аnd thе Amеriсan sсiеnсе-rеligion quarrеl gainеd nеw lifе. BIBLIOGRAPHY Gilkе,v,L B. 1985. Сreаtiс'lпistltсуl Triаl: Еuсllцtfuп апd Glld аt Littlе Roсk. Мinnеapolis: \й/instсlnPrеss. Gish' D. 197З. Еuolutiсlп: Tbе Fossils Sar, No/ San Diеgo: Сrеatiсln-Lifе. -Гhе Numbеrs, R' L. 2006. Сrеаtklпists: From Sсiепtifiс Сrеаtioпism to lпtеlligепt Dеsign. ЕхBandеd еd. СamЬridgе, МA: Harvard Univеrsity Pгеss. Pеnnoсk, R., and.М. Rusе, еds. 2008. But Is lt Sсiепсe? The Philosoohiсаl Quеstioп iп tЬе'Сrеаtion/Еuolutioп Ссlпtrrп,,еrs\,. Updatеd есl. BLrffаlo. NY: Promегhеus. Rusе, M., еd. 1988. Bиt ]s lt Sсiепсс? Tbе Рbilosгlpbicаl Quastiсn iп tbе Сrеаtkтп/Еuolиtioп Сoпtrouersy. Buffalo' NY: Promеthеus. WhitсomЬ' J. С., аnd H. М. Мorris . 1961. The Geпеsis Fklod: Тhе Bibliсаt Rеcсlrd апd lts Sсiепtifiс Impliсаtiсlns. Philadеlphia: Prеsbytеrian and Rеformеd PuЬlishiпgСoп-rpаny. -М.R.

Artifiсial Lifе programs and еvolution Еvolution is thе dеfining propеrty and сrеativе pгoсеss of litЪ, on еarth and whеrеvеrit may oссur. Thе сhееtah running down its prеy' thе hummingbird pollinаting a flowеr, and thе drama сlf thе human mind arе all produсts of еvolution' Lifе hаs сomplеtеly rеshаpеd thе srrrfaсе of our plаnеt and is bеginning to proЬе thе rеst of our solar systеm. Sinсе Dаrwin and Wallaсеunrаvеlеd thе mystеry of еvolution' many sсiеntistshavе studiеd its dеtails.A rеlativеly nеW approaсh to thе study of еvolution is to сrеatе nеw instanсеsof еvolution' an approaсh that hаs Ьееn сallеd Artifiсial Lifе. !Иhilе millions of living spесiеsсurrеntly еxist on еarth' it is Ьеliеvеd that theyall traсе Ьaсk to a сommon anсеstor' Ьillions of yеars аgo; thus thеrе is only a singlе trее of lifе on еаrth. From this pеrspесtivе,our еnriге sсienсеof biologyand our еxpегiеnсеwith еvolution is Ьasеd on a samplе sizе of onе. A trulyсomparаtivе Ьiology аnd а tгuly Ьroad pеrspесtivеon еvolution would rеquirеknowlеdgе of othеr instanсеs of lifе and its gеnеrativе proсеss' еvolution. It is Ьеliеvеd thаt lifе еxists on many planеts throughout thе untvеrsе Ьut,unfortunatеly, thеy arе out of our rеaсh' In its еssеnсе,thе proсеss of еvolution involvеs sеlf.rеpliсating еntitiеs with gеnеtiсvariаtion аnd diffеrеntialsurvival, whrсh lеads to сhangеsin thе сharасtеristiсsof thе population of еntitiеs ovеr thе сoursе of gеnеrations. [,ifе on еаrthis thе produсt of еvolution inhаЬiting thе mеdium of сarЬon сhеmistry; howеvеr,thе proсеss of еvolution сan opеratе in othеr mеdia as wеll. Thеrе has Ьееn somе spесulation among physiсists that thе univеrsе itself may bе thе produсt of еvolution. Somе havе suggestеdthat Ьlaсk holеs givе birth to nеw univегsеs, and that thе fundamеntal сonstants of physiсs may varyamonЕ]univеrsеs.Univеrsеsthat produсе morе Ьlaсk holеs havе a highег Darwinian fitnеss, lеading to thе еvolr'rtionof thе fundamеntal сonstants of physiсs,whiсh govеrn tlrе сharaсtеristiсs of univегsеs.

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Artifiсiаl Lifе Progrаms апd Еuolиtiсlп Spесulation asidе, wе hаvе disсovеrеd that еvolution сan inhaЬit thе mеdium of digital сomputation. If wе aссеpt that еvolution is thе dеfining propеrty and сгеаtivе proсеss of lifе, thеn instanсеsof digitаl еvolution may also Ье сonsidеrеd instanсеs of lifе, alЬеit dramatiсally irliеn lifе. If wе had thе opportunity to obsеrvе lifе on othеr plаnеts, it likеly would Ье сarЬonЬasеd lifе and thus would havе thаt muсh in сommon with lifе on еarth. Artifiсial lifе in thе digital mеdium sharеs only thе еvolutionary proсеss itsеlf in сommon with lifе on еarth' and so is morе aliеn than lifе on сlthеrplanеts. Thе digitаl сomputational mеdium is not a physiсal/сhеmiсalmеdiium;it is a logiсal/informational mеdium. Thus thеsе nеw instanсеs of еvolution arе not suЬiесt to thе samе physiсal laws as organiс еvolution (е.g.'thе laws of thегmodynаmiсs),arrd thеrеforе thеy еxist in whаt amounts to anothеr uni..physiсal laws'' of thе logiс of thе сomputеr. Thеy vеrsе' govеrnеd Ьy thе ..sее'' nеvеr thе aсtual matеrial from whiсh thе сomputеr is сonstruсtеd;thеy sее only thе logiс аnd rulеs of thе СРU and thе opеrаting systеm.Thеsе rulеs arе thе only ..natural laws'' that govеrn thеir Ьеhavior. Thus thеy livе in a radiсally aliеn univеrsе. Inoсulating еvolution into thе digital mеdium givеs us a Ьroadеr pеrspесtivесln what еvсllutionis and what it doеs. Onе of thе most suссеssfulapproaсhеs for сrеating digital еvolution is to ..digitalorwritе sеlf-rеpliсatingсomputеr progrems, whiсh havе Ьееn сallеd ganisms'' or simply ..сrеaturеs,''and run thеm on a сOmPutеr with a Darwinian opеratingsystеm.A Dаrwinian opеratingsystеmmanagеsa populаtion of rеpliсating digital organisms in suсh а Way that whеn nеw сrеaturеs arе Ьorn, oldеr onеs diе to frее spaсе in thе mеmоry inhaЬitеd Ьy thе programs. Thе Darwinian opеrating systеm also introduсеs mutation Ьy flipping Ьits (Ьеtwееnzеro and onе) in thе сodе of thе сrеaturеs.Thе random mutations сausе gеnеtiс variаtion in thе population' with thе rеsult that sсlmеindividuals arе aЬlе to rеproduсе Ьеttеr thаn othеrs, wl.riсhlеаds to а natural proсеss of Darwinian еvolution in аn artifiсial digital mеdium. Although this produсеs a dramatiсally aliеn instаnсе of еvolution, it is found to havе somе striking parallеls to organiс еvolution on еarth. Pеrhaps thе most signifiсantfinding is that thе digital organisms еvolvе adaptationsto thе pгеsеnсеof othеr digitаl organisms in thеir еnvironmеnt. A digital есology еmеrgеs,whiсh Ьесomеsthе main driving forсе of еvolution. A сomputеr сan Ье sееdеd with a singlе sеlf-rеpliсatingdigital organism, whiсh will quiсkly rеproduсе and fill thе mеmory of thе сomputеr with а population of сrеaturеs.Thе сrеaturеs arе thеn a vеry prominеnt fеaturе of thе еnvironmеnt and Ьесomе an important sourсе of sеlесtivеforсеs. Pаrаsitеs arе onе of thе first things that typiсally еvсllvе, and thеy sеt off an есologiсal-еvolutionarydynаmiс that lеads to an ongoit-tgsеriеsof еvolution. arу innovations. .sfhatеvеr kind of сrеaturе is most сommon Ьесomеsa targеt for ехploitation Ьy othеr сrеaturеs. Or if parasites Ьессlrnес()mm()n' thеy drivе othеr сrеaturеs to еvolvе dеfеnsеs.A typiсal sсеnаrio would Ьеgin with thе еvolution of parasitеs' followеd Ьy thе еvolution of immunity Ьy tlrеir hosts. This

сyсlе сan rеpеаt sеvеra parasitеs'' that aсtually Somеtimеs, whеn on( suсh that all thе сrеatu сiality in whiсh individ d u с е , Ь u t с г е а t u r е sl i v i this kind of digital wor matе to produсе young gеnеtiс matеrial intо th tion сontinuеd еvеn wl сrеaturеs had invеntеd produсеd сontaining m еnt. It involvеs a kind o nеtiс matеrial from thе havе diеd. Whilе thе есologiсal driving forсе for еvolu onе form of еffiсiеnсy duсе an offspring. Thi: gеnomе that dеsсriЬеst makе a сopy. Howеvеr еvolution of morе сom1 Thе еvolution of mo grail of Artifiсial Lifе. t plеx and Ьеautiful lifе : gеnеratе сomplехity th unrеalizеd goal of Artil opеn-еndеd еvolution,l as oссuгrеd On еarth. Lifе appеarеd on еar form of singlе.сеllеdol point in timе, lifе madс singlе-сеllеdforms lасk forms with сomplех ani сapаЬlе of сoordinatr сurrеd so aЬгuptly that еxplosion of divеrsity.' Somе havе put forth sеrvе for digital organ сould сontriЬutе somе t prеsеrvе' and digital or1 putеr to сomputеr, fеес that if a large and сomр naturе, thеn a digital С' oссЦr thеrе.

Artifiсiаl l,ife Prс>grаmsапd Еuolиtion rat еvolution сan inhaЬit thе t tlrаt еvolutiсlnis thе dеfining t а n с е st l f . l i g i r e lе v o l u t i < l nm a y amatiсаllyaliеn lifе. If wе had rеts,it likеly wor"rldЬе саrborrсommon with lifе on еarth. Arproсеss itsеlf in hе еvolr'ltitlпаry iеn than lrfс on othеr planеts. mеdiunl; it is ph,vsiсal/сlrеmiсal n е w i n s г . t t r с е. 'si е v o l u r i o n a r е а n i с е v o l u t i o n( е . g . 't h е l a w s o f r 'д,hаtamounts t() anothег uni_ hе logiс of thе сomputеr. Thеy 1есomputегis сonstГuсteсl;thеy 1е opеrаtingsystеrn.Thеsе rulеs ir Ьеhavior.Thus thеy livе in a ' l r i n t o t h е t l i g i r a ln i с d i t r m g i v е s s and rvhat it doеs. r с r е a t i n 8t,l i g i t а lе v o l u t i o n i s t с > ..digital orriсh hаvе Ьееnсallеd lеm On a сOmputеr with a Daring systеrrrmanagеs a populatiorr aу that wЬеп nеrь"сIеatlrrеs arе nory inhaЬitеdЬу thе progгams. ldttсеsmutation Ьy flipping bits r е i т u r е sТ . hе гantlommutations itlr thе rеsult thertsomе individLr_ wlriсh lеаds to a natural proсеss ll rnеditrm. а l i е n i n s t a n с еt l f е v o l u t i o n , i t i s 3aniсеvolLrtionon еarth. Pеrhaps l o г g а n i s п rеs v o l v с a d a p t а t i o n st o :hеir еnvironmеnt.A digital есol. :ng fсlrсеof еvoltrtitlrr. s е l f - r е p l i с a t i ndgi g i г a l o r g a n i s m , mеmory сlf thе сomputеr with a thеn a vеry promillеnt fеaturе of t sourсе of sеlесtivе forсеs. Para;irlly еvolvе, arrd tlrеy sеt off an to an ongoing sеriеs of еvolutionron Ьесoпtеsа targеt for еxploitaесOmесommon' thеy drivе othеr rаrio would Ьеgin with thе еvolu-rof immunity Ьy thеir hosts. This

сyсlе сan rеpеat sеvеral timеs Ьut may progrеss to thе еvolution of ..hypеrpaгаsitеs''that aсtually аttaсk parasitеs,stеalingthеir еnеrgy. Somеtimеs,whеn onе kind of сrеаturе сomplеtеly d
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Artificiаl Life Progrаms апd Еuolиtiсlп Humans havе Ьееn managing thе еvolution of othеr spесiеsfor tеns оf thousands of yеars through thе domеstiсation of plants and animals. It forms thе .Wе managе еvolution Ьasis of thе agriсulturе that undеrpins our сivilizations. through Ьrееding' thе аppliсation of artifiсial sеlесtion to сaptivе populatiоns. Similar approaсhеs havе Ьееn dеvеlopеd for working with еvolution in thе digital domain. It forms thе Ьasis of thе fiеlds of gеnеtiс аlgorithms and gеnе' tiс programming. Howеvеr, Ьесausе digital еvolution has not yеt pаssеd through its vеrsion of thе CamЬrian еxplosion, thеrе еxists thе possiЬility to ..managing'' digital еvolution. .!Иеnееd usе a radiсally diffеrеnt approaсh to not limit oursеlvеs to using еvolution to produсе superior versiоRs of.qхisting softwarе appliсations. Rathеr, wе should аllow еvolution to find thе nей appliсations for us. To sее this proсеss morе сlеarly' сonsidеr how wе managе appliсations through organiс еvolution. Somе of thе appliсations providеd Ьy organiс еvolution arе riсе' сorn' whеat, сarrots' Ьееf сattlе' dairy сattlе' pigs, сhiсkеns, dogs, сats' guppiеs, сotton, mahogany' toЬaссo, mink' shееp, silk moths, yеast, and pеniсillin mold. If wе had nеvеr еnсountеrеd any onе of thеsе organisms' Wе would nеvеr havе .Wе havе madе thеm into appliсations Ьесausеwе rесthought of thеm еithеr. ognizеd thе potеntial in somе organism that was spontanеously gеnеratеd within an есosystеm of organisms еvolving frееly Ьy natural sеlесtion. Мany diffеrеnt kinds of things oссur within еvolution. Brееding rеlаtеs to ..Ьеttеr,'' еvolution within thе spесiеs, produсing nеw and differеnt, possiЬly forms of ехisting spесiеs. Howеvеr, еvolution is also сapaЬlе of gеnеrating spесiеs. Еvеn morе signifiсantly, еvolutiоn is сapaЬlе of сausing an ехplosivе inсrеasе in thе сomplеxity of rеpliсators, through many ordеrs of magnitudе of сomplехity. Thе СamЬriаn еxplosion may havе gеnегatеda соmplехity in. сrеasе of еight ordеrs of magnitudе in a span of 40 million yеars.Harnеssing thеsе еnormously morе сrеativе propеrtiеs of еvolution rеquirеs a сomplеtеly diffеrеnt approaсh. .Wе know how to apply artifiсial sеlесtion to сonvеrt poсlr-quality wild сorn into high-yiеld сorn. Howеvеr' wе do not know how to Ьrееd algaе into сorn. Thеrе arе two Ьasеs to this inaЬility: (1) if all wе know is algaе, wе сould not еnvision сorn; and (2) еvеn if wе know all aЬout сorn' Wе do not know how to guidе thе еvolution of algaе alоng thе routе to сorn. our ехpеriеnсе with managing еvolution сonsists of guiding еvolution of spесiеs through vаriations on ехisting thеmеs. It doеs not сonsist of managing thе gеnеration of thе thеmеs thеmsеlvеs. An altеrnativе is to lеt natural sеlесtion do most of thе work of dirесting еvolution and produсing сomplеx softwarе.This softwaгеwill Ье ..wild,'' liv. ing frее in thе digital Ьiodivеrsity rеsеrvе. In ordеr to rеap thе rеwards and сrеatе usеful appliсаtions, wе will nееd to domеstiсatе somе of thе wild digital organisms, muсh as our anсеstors Ьеgan domеstiсatingthе anсеstors of dogs and сorn thousands of yеars ago. This vision of digital naturе is сurrеntly unattainaЬlе, and may always rеmain so. Still, mаny геsеarсhеrsin thе fiеld of Artifiсiаl Lifе arе still working toward an opеn-еndеdеvolution in thе digital mеdium.

Although thе vast inс out of rеaсh, morе moс approaсh has Ьееn to fе pеrforming сomputatio plеx сomputations. Thr algorithms and has Ьее to produсе what appеa Studying organiс еvс oссurs ovеr vast sсalеs proaсh to thе study of sеrvе thе proсеss of еv modеst сomplехity. Als. allowing us to know tht вlвLIoGRAPHY

Adami, С. 1998.Iпtrrldu G o l d b е r gD ' . Е . 1 9 8 9 .С е Lеаrniпg. Rеading,N Koza, J. R. 1992.Cепеtt Меапs of Nаturаl Sе l - а n g t o nC' . G ' . е d . l 9 q 5 . Lеnski,R. Е., с. Ofriа,R. of сomplех fеаturеs.] Lеvy, S. 1'992'Artifiсiаl Li Books. R a y , T . s . 1 9 9 1 .A n а p p r J. D. Farmеr,and S. F Workshс'ptlп Аr!ifiсi .!Иеslеy.

1994a.Еvolutiоn 239_26з. |994ь. An еvolu r. r' .L "d tr ir .r .r a t

r| ri rЁL".

r 4r '. t. ,i f/ ,r L. li 6 1

еd.,Аrtifiсiаl Life: Ап Smolin, L. 1997. Thе Lifе

Ayala, FranсisсoJ.

Franсisсo J. Ayala was l guishеd mеmЬеr of thе knowlеdgеd for his stu sсiеnсе.Hе has bееn Dс vеrsity of Сalifornia at U n i v е r s i г yo f С а l i f o r n i Ayala's сarееr has сot еxpansion of molесular has Ьееn a lеadеr in Ьotl

фаlа оtlrеrspесiеsfor tеns of thor-rrnts and animals. It forms thе .$Ие managе еvolution zations. ,есtionto саptivе popLrlаtions. working with еvolution in thе f gеnеtiсalgorithms and gеnеэvoltrtionhas not yеt passеd to , thеrееxists thе possibility .Wе nееd еvolution. digital rg'' :е supеriorvеrsionsof еxisting l еvolution to find thе nеw aprrly, сonsidеr how wе managе aniс еvolution arе riсе, сorn, . с k е n sd. o g s ,с а r s .g u p p i е s ,с o t thsoyеast,аnd pеniсillin mold. rganisms,wе would nеvеr havе гo appliсationsЬесausеwе rесwas spontanеouslygеnеratеd эly Ьv naturаl sеlесtion. t еvolutiorr'Bгееding rеlatеs to ..Ьеttеr,,' nd diffеrеnt,possiЬly l i s . r l s oс а p a Ь l еo f g е n е r a t i n g :apaЬlеof саusing an еxplosivе ugh many ordеrs of magnitudе ravеgеnеratеda сomplехity inэ f 4 0 m i l l i o n у е a r s .H a г n е s s i n g evolutionrеquirеsа сomplеtеly r to сonvеrt poor-quality wild t krrow how to Ьrееd algaе into 1) if all wе know is algае, wе now all about сorn, wе do not ng thе routе to сorn. Our ехpеt guiding еvolution of spесiеs еs not сonsist of mаnaging thе l most of thе work of dirесting ..wild,'' liv. 'his softwarеwill Ье ordеr to rеap thе rеwards and mеstiсatеsomе of thе wild digidomеstiсаtirrgthе аnсеstors of rattainaЬlе,and may always rеf Artiliсial [,ifе аrе still woгking l mеdium.

Although thе vаst inсrеasеsin сomplеxity еnvisionеd for digital nаture arе out of rеtrсh'mo[е modеst inсrеasеsin сon,rplеxityhavе Ьееn aсhiеvеd. onе approaсh has Ьееn to fееd numЬеrs to digitаl organisms аnd rеward thеm for pеrfоrming сomputations on thеm; grеatеr rеwards arе givеn for morе сomplех сomputations. This аpproaсlr has lеd to the еvolution of quitе сomplех algorithms ar-rdhas Ьееn usсd as a dеtnonstrаtionof thе aЬility of сvolutiоrl ..irrеduсiЬly''сomplех stгuсturеs. tо produсе whаt appеar to bе Studying organiс еvolution сan Ье frustrating Ьесausе it is a proсess that oссurs ovеr vast sсalеs of timе and spасе. Artifiсial Lifе is an еxсiting appгoaсh to thе stlldy ф еvolution Ьесausе it providеs an opportunity to oЬsеrvе thе proсеss of evo'lution in aсtion, gеnеrating novеlty, есologiеs, and modеstсonrplехity.Also,.it Ьroadеns our pеrspесtivеon lifе and еvolution Ьy allowing us to know thе еvolutionary proсеss in a nonorganiс mеdium. BIBLIoGRAPнY Adami, С. 1998,lпtroduсtioпto Аrtifiсiаl Llle. Nеw Yoгk: Springеr-Vеrlag' GoldЬеrg,D. Е. 1989. GепеtiсАIgorithmsiп Seаrсh,optimizаtioп, аnd Масhine Leаrпittg.Rеadirrg,МA: Addison-Wеslеy. Kоza' J. R' 1992. GeпеtiсPrr-lgrаmmiпg: Оп thе Progrаlnmiпgof Сomputеrsbу Меапs of Nаturаl Selесtit'lп. СamЬridgе'МA: tr4ITPrеss. Lаngton,С. G., еd. |995, АrtifiсiаlLifе: An Оt,eruieш. СаmЬridgе,МA: МIT Press. l-еnski,R' I].,с. Ofriа, R. T. Pеnnoсk'аnd С. Adami. 2003.Thе еvolutionaryorigin of сomplехfеaturеs.Nаturе 423: 139_144. Lеvy,S. 1992.Аrti|tс:iаlLifе: Thе Quеst for а Neш Сrеаtioп.Nеw York: Pаnthеon Books. Ray,T. S. 1991'An approaсhto thе synthеsisof lifе.In C. G. Langton'С. Taylor, J. D. Farmеr,and S. Rasпrussеn,еds.'Аrtifiсiаl Life II: Procееdingsof the Workshсlpoп ArtifiсiаlLife' vr>|' l1, 371_408.RеdwoodСity, СA: AddisonWеslеу. 1994a.Еvolution' сonrplехity'еntropy'аnd аrtifiсialrеality.PhуsiсаD 75: 2.з9_26з. 1994ь.An еvolutionаrry approасhto synrhеtiсЬioiogy:Zen and thе art of сrеating\ifе,Аrtifiсiаl Liiе 1, no. |l2: 179-209. Rеprintеdin С. G. Langtоn' еd.,ArtifiсiаlLiiе: Ап Оuеп,iеш,|79-209. СаmЬridgе,MA: МIT Prеss,1995. Smolin,L' 1997.TheI'ifеof tЬе Сoяпrls.Nец,York: Oхford Univеrsityo'..,-'.*.

Ayala,FranсisсoJ. (b. 1934) FranсisсoJ. Ayala was Ьoгn in Madrid' Spain, on Marсh 12, 1'9З4.A distinguishеdmеmЬеr of thе intеrnationаl sсiеntifiс сommunity, hе has bееn aс. krrowlеdgеdfor hls studiеs in еvolurionary Ьiologv and thе philosophy of sсiеnсе.Hе has bееn Donald Bren Profеssor of Biologiсal Sсiеnсеs at thе Univеrsity of Сalifornia at Irvinе sinсе 1987 аnd Univеrsity Profеssor of thе Univеrsityof Сalifornia sinсе 2003' Ayala,s сarееr has сoinсidеd with and' to a largе еxtеnt' has lеd thе risе and ехpansion of molесr.rlаrеvolution аnd thе philosophy of Ьiology. Indееd, hе hаs Ьееn :r lеadеr in Ьoth fiеlds for many yеars. Aftеr his еarly invеstigаtions of

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434 Ауаlа thе proсеss of spесiation and thе rolе of gеnеtiс variation in еvоlurion, pеrformеd using traditional gеnеtiс mеthods whilе hе was a graduatе studеnt, hе saw that thе dеvеloping tесhniquеs of molесular еvolution mаdе possiЬlе a morе powеrful approaсh to thеsе issuеs.Latеr in his сarееr, Ayala usеd molесular mеthods to еluсidatе thе еvolutionary origin and population struсturе of Trуpаtьosomа' Plаsmodillm, and othеr human parasitеs.Thе impaсt of Ayala's ..Biology сontriЬutions to thе philosophy of Ьiology startеd in еarnеst with his ..Tеlеologiсal as an Autonomous Sсiеnсе'' \Аmеriсаn Sciеntist, 1968) and his Ехplanations in Еvolutionary Biology,, (Philosophу of Sсiепсe, 1970). As a youth, Ayala was intеrеstеd in sсiеnсе and dесidеd to study physiсs at thе Univеrsity of Мadrid. Latеr' as а rеsult of his philosophiсal and rеligious inсlinations, hе immеrsеd himsеlf for fivе yеars in thеоlogy at thе Univеrsity of Salamanсa. tуala nеxt dесidеd to Ьесomе an еvolutionist, сoming to,thе Unitеd Statеsin 1961iЬe Ьесamе an Amеriсan сitizеn tn 1977. Undеr thе adviсе of his formеr Spanish tеaсhеrs, gеnеtiсists Fеrnando Ga16n and Antonio de Zulueta, Ayala studiеd еvolution from a gеnеtiс pеrsРесtivе with Thеodosius DoЬzhansky, thе Russian-Ьorn Amеriсan gеnеtiсist, at Columbia Univеrsity in Nеw York Ьеtwееn 7961 and 1964' During his thrее yеars as a graduatе studеnt at Сolumbia hе сarriеd out invеstigations aЬout thе proсеss of spесiation in Australian Drosophilа and disсov. еrеd сryptiс spесiеs and intеrmеdiatе stagеs of spесiation. Не introduсеd nеw mеthods for mеasuring population fitnеss and dеmonstratеd that thе гatе of еvolution сorrеlatеd with thе lеvеl of gеnеtiс variation. Thеsе studiеs wеrе publishеd in 1965-1966 in a sеriеs of papегs in Sсiепcе' Genetics' Еuolиtioп, Аmеricаn Nаturаlist, aпd Pасifiс Iпsесts. In 1,965,as a postdoсtoral fеllow' Ayala introduсеd еlесtrophorеtiсtесh. niquеs for dеtесting prоtеin polymorphisms in Dobzhansky's lаЬoratoгy at Roсkеfеllеr Univеrsity. Hе Ьесamе an assistantprofеssorthеrе in 1967.With thеsе morе powеrful tесhniquеs, hе now аpproaсhеd thе еarliеr proЬlеms of mеasuring gеnеtiс variation (polymorphism) and how this impaсtеd thе ratе of еvolцtion. Hе also initiatеd a сomprеhеnsivе invеstigation of thе gеnеtiс сhangеs сonсomitant to thе spесiation proсеss and thе еvolution of rеproduсtivе isolation. Invеstigations сomЬinеd laЬоratory ехpеrimеnts with thе invеstigation of natцral pоpulations of Drosophilа шillistonl and rеlatеd spесiеs of the Amеriсan tropiсs. Не puЬlishеd thе first сomparative data analyzing gеnеtiс diffеrеntiation as a funсtion of taхonomiс lеvеl in Drosophilа spp.' as wеll as in various othеr animal groups. In сollaЬoration with DoЬzhansky, Ayala сonfirmеd thеorеtiсal prеdiсtions aЬout thе distriЬution and adaptivе signifiсanсе of gеnеtiс variaЬility in natural populations. onе main сontriЬution to еvolutionary Ьiology was his dеmonstration that thеrе is muсh morе gеnеtiс polymorphism in natural populations than prеviously thought. Не Ьесаmе а lеading partiсipant in thе сontrovеrsy rеgarding whеthеr molесular polymorphisms Wеrе adaptivеly nеutral or drivеn Ьy natural sеlесtion.Hе arguеd forсеfully for thе lеading rоlе of natural sеlесtion Ьasеd on thе distriЬution of ехtеnsivе, Ьut gеographiсally fairly uniform' gеnеtiс polymоrphisms in natural populations of Drosophilа in

thе Amazon Ьa ratory ехpеrlmе and othеr еnvir that natural sе phism. Hе dеv and frеquеnсyI л 1 ' 9 7 1 ,А у a thе Univеrsity t palеontologist J thе 1 970s tha сlams; Antarсti starfish' sеa urс thе amount of sourсеs' Ьut on сomе adaptеd t promptеd nеw fossil rесord. During thе 1 ifornia аt Irvinе еasе' whiсh is а Hе showеd thа thought at thе t с l o n a l t h е o r yo { turе of thеsеpа man sсourgеsr( -N4orеrесеntl pаrum, thе agе that thе world t rесеnt' starting that thе spесiе еvolvеd in rеsp In addition tс of Ьiologiсal pr tinсtivе сhaгaсt tions to thе phiJ of natural sеlес of living forms. tiсularly, еvolu larization of еr forсеfully arguс nееd not Ье in с Ayala has ех makеs sеnsе ех еvolution makе Franсisсo J. , wеll as thе autl

Aуаlа variationin еvolution, pеrwas a graduаtеstudеnt,hе еv
thе An-razonЬasin anсl tlrroughout thе Caгibbеan islands. Не dеsignеd laboratоry еxpеrimеrrts tЪг mеasuring tlrе еffЪсtthе amount of food, livirrg spасе, and сltherеnvironnrеntaIfaсtors hаd on population fitnеss.Rеsults сorrfirmеd that natural sеlесtion Was thе driving faсtoг impaсring gеnеtiс polymorphisnr. Hе dеvеlopеd IaЬoratory mеthods for mеasuriIlg dеnsity.dеpеndеnt and fгеquеnсy-dеpеndеntnаtural sеlесtion. In |97|, АyаIa and DoЬzlrаnsky movесl to thе Dеpагtmеnt of Gеnеtiсs at tlrе Univеrsity of Саlifоrnia at Davis. At UC Davis, Ayala сollaЬoratеd with palеontologistJamеs \W. Valеntinе irr а sеriеs of invеstigationspublislrеd in thе 1970s that involvеd divеrsе organisms, inсluding tropiсal Тrid,асnа сlams; Antarсtiс, tеmpеrаtl, and tropiсal oсеaniс shrimp; and dееp-oсеan starfish,sеa urсhins, and Ьraсhiopods. Tlrе invеstigationsdеmonstratеdthat thе amсlunt оl gеnеtiс vаriaЬrlrty с1еpеndеdnot On thе abundanсе of rеsourсеs'Ьut on еnvironmеntal staЬility, whiсh allows gеnеtiс variants to bесomе adaptеd to diffеrеnt еnvirоnmепtal fеaturеsand rеsourсеs.Thе rеsults promptеd nеw hypothеsеsto ехplain thе major ехtinсtions oЬsеrvеd in thе fossil rесord. Duгing thе 1980s' rvorkirrgаt UС Dаvis and latеr at thе Univеrsity of Сaliforniа аt lrvinе, Ay:rlа studiеd TrуpLl'Iosomасruzi, thе agеnt of Сhаgas disеasе,whiсh is a sеvеrе disеasе еndеnriс in many South Amеriсan сountriеs. Hе showеd that it rеproduсеs сlonally, rathеr than sехually, as gеnеrally thougl-rt at thе timе. Ayale and сollaЬor;rtorМiсhеl TiЬayrеnс formulаtеd thе сlonal tlrеory of parasitiс protozoa. Тhеy proposеd that thе population struсturе of thеsеparilsitеs is prеvailinglv сlonal, еvеn though thеsе pеrvаsivе humа11sсourgеsrеtain thе сapасity for sеxual rеproduсtion. Мorе rесеntly, Ayala has rесonstruсtеd thе еvolution of Plаsmodium fаIсipаru|п' thе аgеnt of malignant malaria' and rеlatеd spесiеs.Hе has shown that thе world ехpansion of P. fаlсipапltzzthroughout thе tropiсal rеgions is rесеl1t'starting from :r singlе Afгiсan propagulе аrrrund 5,000 yеаrs ago, and tlrat thе spесiеsis gеrrеtiсallylargеly uniform, ехсеpt for mutations rесеntly еvolvеdin rеsponsеto thе human imt-nunеsystеm and to mеdiсinеs. In addition to his еssayson Ьiology as an autonomous sсiеnсе,thе сonсеpt of Ьiologiсal progrеss' and thе idеа of tеlеology, Ayala has еxplorеd thе distinсtivесharaсtегistiсsof thе sсiеntifiсrrrеthod.Hе has m:rdеothеr сontгiЬutions to thе philosophy of sсiеnсе,inсluding еxplorarions of how thе proсеss of r-ratural sеlесtionprovidеs a сausаl ехplanation of tlrе еvolution and dеsign of living forms. \й/ithехtеnsivеknowlеdgе of thе history of Ьiology and, partiсuIirrly,еvolutionаry thеoriеs, hе has сontributеd ехtеnsivеly to thе Popularization of еvolutitlnаry thеory as thе сеntral сorе of biology. Hе has forсеfullyarguеd thirt tlrе tlrеor'l'of еl,olution, as wеll as sсiеnсе in gеnегal, nееdnot Ье in сorrtrzrdiсtionwith rеligious Ьеliеfs. Ayala hаs ехtеndеd DoЬzhansky's rеnownеd phrasе ..nothing in Ьiology makеs sеnsе ехсеpt in the light of еvolution'' with thе phrase ..nothing in еvolutionmakеs sеnsееxсеpt in thе ligЬt of gеnеtiсs.'' Frаnсisсo J. Ayala is thе author of пroге thаn 900 spесializеd artiсlеs as wеll аs thе author or еditor of mсlrе thаn 20 Ьooks. Не is a mеmЬеr оf thе

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Aуаlа National Aсadеmy of Sсiеnсеs, thе Amеriсan Aсadеmy of Arts and Sсiеnсеs, thе Amеriсan Philosophiсal Soсiеty, thе Сalifornia Aсadеmy of Sсiеnсеs,thе Russian Aсadеmy of Sсienсеs,thе ltalian Aссadеmia Nazionalе dеi Linсеi, and aсadеmiеs of othеr сountriеs' inсluding Меxiсo, SеrЬia, and Spain. Hе has sеrvеd as prеsidеnt of thе Amеriсan Assoсiation for thе Advanсеmеnt of Sсiеnсе, thе Sigma Хi Thе Sсiеntifiс Rеsеarсh Soсiеty, and thе Soсiеty for thе Study of Еvolution. Hе has rесеivеd numеrous honors and awards, аnd hе has Ьееn dеsignatеd Doсtor Honoris Саusа Ьу univеrsitiеs in Argеntina, Сzесh RеpuЬliс, Grеесе, Italy, Мехiсo, Spain, and Russia. In 2002 hе rесеivеd thе National Меdal of Sсiеnсе, thе highеst sсiеntifiс award in thе Unitеd Statеs, from Prеsidеnt Gеorgе W. Bush. в|BLIoGRAPнY

Ayala, F. l. |965a. Drсlsophilаdomiпiсапа,a nеw siЬlingspесiеsof tЬeSerrаtа grolp. Pасфc lпsесts7: 62О-622. 1965ь. Еvolution оf fitnеssin ехpеrimеntalpopulationsof Drosophilа serrаtа'Sсieпсе150:903_905. 1965с.SiЬlingspесiеsof tЬе Drosophilа serrаtаgroup.Еuolutioп 1.9z 538-545. t966a. Dynamiсsof populations.I. Faсtorsсontroilingpopulationgrowth and populationsizе in Drosophilа sеrrаtа.Tbе Amеriсаn Nаturаlist 100: 3з3-344. |966ь. Еvolution of fitnеss.I. Improvеmеntsin thе produсtivityand sizеоf irradiatеdpopulationsof Drсlsophilаserrаtаand Drosopbilа birсhii. Geпetiсs 5 3 :8 8 3 - 8 9 5 . 1968.Biologyas an autonomoussсiеnсе.AmеriсапSсiепtist56:2О7-221. 1970.Tеlеologiсalеxplanations in еvolutionaryЬiologу.Philosopbуof Sсieпсе37: 1-|5. 2О06.Dаrtl,iп апd lпtelligeпtDesigп,Мinnеapоlis,МN: FortrеssРrеss. 2О07.Dаrшiп'sGift to Sсieпсeапd Rеligioп..Washington' DС: Josеph Неnry Prеss. .!И. H.y, J., М. Fitсh, and F. J. Ayala, еds.20О5.Sуstemаtiсsапd thе origin of .Washington, Spесiеs:Оn Еrпst Мауr's 100thAппiuеrsary. DС: National AсadеmiеsPrеss. Russеll'R.J., !и. R. Stoеgеr'and F. J. Ayala'еds.1998'Еuolutioпаrуаnd Мolесulаr Biologу: SсieпtфсPеrspесtiuеs oп Diuiпе Асtitlп. VаtiсanСity Statе/Bеrkеlеy, СA: Vatiсаn С)Ьsеrvatoryаnd thе Сеntеrfor Thеologyаnd thе Natural -A.B. Sсiеnсеs.

Baсtеrial еvolution

Thе MiсroЬе is so vеry Y o u с a n n o тm a k еh i n l B u r m а n уs а n g u | npее To sееhim throughtht

Aсtually, Hilairе Bеlloс, w out of datе. МiсroЬеs wе looking at sсrapings from labеlеd bасtеriа in 1828 L Ьеrg' from thе Grееk wor ogists disсovеrеd thе еr undеrstand that divеrsity е v o l u t i o n o f Ь a с t е r i ai s o еxсiting arеas of study. B а с t е г i а a r е r е l а t i V е l y: mеaning that thеy do not thе gеnеtiс matеrial is hou baсtеrial сеll. First, thеrе сеll гhat primаrily сaгriе сomponеnts. Sесond, thеr primarily involvеd with rr

not havе morе sophistiсat for powеr gеnеratiоn) or with сells that do havе nu organеllеs usеd for Ьuild Thеy rеproduсе Ьy simplе аnd еaсh daughtеrсе1lis l Likе all organisms, Ьa tion: сеlls with advantag thеm. Advantagеous fеat First, thе gеnеs of Ьaсtе vеrsity сan aссumulatе r: of sехual rеproduсtion tl gеnеtiс matеrial оn thеir t h а г h а v е a r i s е ni n o n е с е

Aсadеmy of Arts and Sсiеnсеs' ornia Aсadеmy of Sсiеnсеs' thе :сadеmia Nazionalе

dеi Linсеi,

Мехiсo, SеrЬia, and Spain. Hе сiаtion for thе Advanсеmеnt of Soсiеty, and thе Soсiеty for thе ,us honors and awards, and hе l Ьy univеrsitiеs in Argеntina' in, and Russia. In Z0О2 hе rеhighеst sсiеntifiс award in thе h.

Baсtеrial еvolution Thе Miсro!е-is so vеry small You сanfot makе him out at all But ma{lysanguinеpеoplеhopе To sееhim thrоughthе miсrosсopе.

l siЬling spесiеsof the Sеrrаtа al populationsof DrosсlphiIа ierrаtа groaP, Еuolutkп

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,rs сontrolling pоpulation growth bе Аmеricап Nаturаlist 1ОО:. :ntsin thе produсtivity аnd sizе of and Drosophilа birсhii. Geпеtiсs Аmeriсап Sсiепtist5 6: 207 -22|. .ionary Ьiologу. Philosсl1lhу of innеapolis,MN: Fortrеss Prеss. .loи. Washington, DC: Jоsеph Sуstеmаtiсsапd thе Оrigin of .Washington, ,. DС: National ' 1998. Еuolutiс-lпаrуапd Мolесulаr :tioп.У atican Сity Statе/Bеrkеlеy, .Thеology and thе Natural

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Aсtually, Hilairе Bеlloс, who wrotе thеsеamusing linеs, Was sеvеralсеnturiеs out of datе. МiсroЬеs wеrе first sееn in 1674 Ьу Antoni van Lееuwеnhoеk, lоoking at sсrapings from his tееth through а simplе miсrosсopе. Thеy wеrе laЬеlеdbасtеriа in 1828 Ьy thе Gеrman Ьiologist Сhristian Gottfriеd Еhrеn..small stiсk.'' In suЬsеquеntyеars' biolbеrg,from thе Grееk Word mеaning ogists disсovеrеd thе еnormous divеrsity of Ьaсtеria. Thе strugglе to undеrstandthat divеrsity, its еvolutionary history, and thе сontinuеd rapid еvolution of Ьaсtеria is onе of еvolutionary Ьiology's most сhallеnging and ехсiting arеas of study. Baсtеria arе rеlativеly simplе, onе-сеllеd organisms' laЬеlеd prokaryotеs' mеaning that thеy do not havе a spесial сompartmеnt' or nuсlеus, in whiсh thе gеnеtiсmatеrial is housеd. Thеrе arе two typеs of gеnеtiс information in a Ьaсtеrialсеll. First, thеге is a small, usually сirсular сhromosomе within thе сеll that primarily сarriеs thе gеnеs rеsponsiЬlе foг Ьuilding thе сеll and its сomponеnts.Sесond, thеrе arе a numЬеr of gеnеs floating in thе сеll that arе primarily involvеd with rеgulating thе сеll's mеtaЬoliс proсеssеs. Baсtеria dо not havе morе sophistiсatеdсеll parts (organеllеs)suсh as mitoсhondria (usеd for powеr gеnеration)or сhloroplasts (usеd' е.g.' Ьy еukaryotеs-organisms with сеlls that do havе nuсlei-for phоtosynthеsis). Thеy do hаvе riЬosomеs, organеllеsusеd for Ьuilding protеins frоm thе instruсtions givеn Ьy RNA. Тhеy rеproduсе Ьy simplе сеll division; onе сеll dividеs into two daughtеr сеlls and еaсh daughtеr сеll is a сlonal rеproduсtion of its rnothеr сеll. Likе all organisms' Ьaсtеria arе opеn to еvolution through natural sеlесtioп: сеlls with advantagеous fеaturеs prolifеratе fastеr than thosе without thеm.Advantagеous fеaturеs arisе in Ьaсtеrial сеlls through thгее avеnuеs. First,thе gеnеs of Ьaсtеria сhangе spontanеously,or mutatе, and сlonal divеrsityсan aссumulatе rapidly. Sесond' somе Ьaсtеria arе сapaЬlе of a kind of sеxual rеproduсtion through thе ехсhangе, Ьеtwееn сеlls' of somе of thе gеnеtiсmatеrial on thеir сhromоsomеs. This gеnе ехсhangе plaсеs mutants thathavе arisеn in onе сеl1linе into othеr сеll linеs. Third, Ьaсtеrial gеnеs that

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Bасtеriаl ЕuсllutЙл afе not on thе main сhromosomе сan oftеn Ье transfеrrеd dirесtly from onе сеll to anothеr. This proсеss' сallеd hсlrizontalgеnе transfеr,сan faсilitatеthе rapid sprеad of a gеnе throughout a Ьaсtеrial сolсlny and сhangе thе сharасtеristiсs of tlrе сolony quiсkly. Bесаusе prokaryсltеs aге sirnplеr than eukary. otеs, thе natural assumption is that thе formеr еvolvеd Ьеforе thе lattеr, and that thе lattеr еvolvеd from anсеst
сonсеntrations of oх1 of thе most сommon of thе еarth's ехistеn availaЬlе. As thе еar risе and sеlесtion prс Ьеgan. Nехt, oхygеn еrgy. Thе first еvidеn сould switсh from o: othеr (using oхygеn) lеvеls сontinuеd to ri 2О"Ь. ЬЬout2.25 ьi]

oЬеs) appеarеd. Еukaryotеs appеa now Ьеliеvеd' thank Margulis, that еuk: among various prok. aЬsorЬеd othеr miсr DNA on thе nuсlеar arсhaеa, it appеars t

сеlls-arе dеsсеndеd today's wеll-known р ing humans.) Thе сЬ photosynthеsis,also truly сhimеras, whiс many diffеrеnt typеs Thе symЬiotiс rеlа сomplеx rеlationshi Baсtеriа today arе ut Many plants dеpеnd thеy сan usе it thеm fеrtilizеrs, and it is v to modify plants gеn tеria, thеy сan thеm ria in thеir stomaсh food. Baсtеria in thс tаin disеasеsor stop usе Ьaсtеria for thеi usеd in сlеaning up t Unfortunatеly' it : animals (еspесiallyh to history, tooth dес mouth: Strеptсlсoсc plеasant Ьaсtеrial di Ьу Муcobасterium i сholеra, сausеd by terium tuberсulosis

BасteriаlЕuolutioп ] transfеrrеddirесtly from onе gеnеtransfеr,сan faсilitatе thе сolony and сhangе thе сharaсyotеsarе simplеr than еukary.еvolvеd Ьеfсlrеthе lattеr, and nЬlеdthе formеr. Тhis assumpthе naturе of сеll funсtion, and tе molесular lеvеl. Thе еarth is y yеars thе surfaсе was far too tЪssii lifе datе Ьaсk to around Fеarsthеrе is solid еvidеnсе of known as Ьluе-grееn algaе. omatolitеs and livеd in thе sеa L nесеssагyсondition of lifе on э form still flourish today. \mеriсan miсroЬiologist Сarl nmon anсеstor-thе parеnt of .Woеsе' 3.5 Ьillion yеars ago. think in tеrms of just a singlе trееof lifе is rеally a piсturе of еritanсе through сеll division )ant horizontal gеnе exсhangе l foсus оf thе еvolutionary prolеs and small сlustеrs of gеnеs. еnеtiс mеthods wеrе not likеly :r, and morе aссuratе, to think , all of whom would havе Ьееn orе aссuratе piсturе of thе trее stounding findings is that thе |ps:thе Ьaсtеria (or truе Ьaсtее Ьееnсallеd, ArсhaеЬaсtеria). aсtеria and arсhaеa. N4ost im:yotеsin thе way thеy rеad and l i s a p p е а r st o Ь е r h е f i r s t m а j o г l and thе сommon anсеstor of ..N{olесular in thе main еssay nе). Маny аrсhaеa arе сapablе xamplе, hot or salty). This had nе of thе еarliеst lifе forms, еsifе was found in vеry hot' dееp.е, Ьaсtеria Ьеgan to losе thеsе n rеgainеd. еs in thе ways in whiсh еnеrgy Ln bе dеtеrminеd from molесul rесord, thе first Ьaсtеriа wеrе эuld not survivе in signifiсant

сonсеntrаtions of oхygеn. Thеy found thеir еnergy Ьy nonoхygеn mеans; onе of thе most сommon mеans was Ьy fеrmеntation. Of сoursе, for thе first half of thе еarth's еxistеnсе' thеrе wеrе no signifiсant сonсеntrations of oхygеn availaЬlе.As thе еarth sustainеd сhеmiсal сhangеs, oхygеn lеvеls Ьеgan to risе and sеlесtion prеSsurеtoward oxygеn-tolеrant (aеrotolеrant)organisms Ьеgan. Nехt, oхygеn-tolеrant organisms Ьеgan to usе oxygеn to prodцсе еnеrgy. Thе first еvidецсе.oJ thе faсultativе aеroЬiс organisms-organisms that сould switсh frбm onе form of еnеrgy produсtion (without oxygеn) to an. othеr (usinglоxygеn)-сan Ье traсеd to aЬout 2.5 Ьillion yеars ago. Oхygеn lеvеls сontiriuеd to risе until thеy wеrе aЬolt 1oЬ of today's prеsеnt lеvеl of 20%. AЬout 2.25 Ьillion yеars ago' еxсlusivеly oхygеn-usingorganisms (aеroЬеs)appеarеd. Еukaryotеs appеarеd shortly aftеr thе еmеrgеnсе of oЬligatе aеroЬеs. It is now Ьеliеvеd, thanks to thе Ьrilliant hypothеsis of Amеriсan Ьiologist Lynn Margulis, that еukaryotеs Wеrе formеd through symЬiotiс intеraсtions among various prokaryotеs. Somе miсroorganisms, prеsumaЬly arсhaеalikе, aЬsоrЬеd othеr miсroorganisms, somе of whiсh wеrе Ьaсtеria. \Whilе thе DNA on thе nuсlеar сhromosomеs of еukaryotеs indiсatе thеir affinity with arсhaеa' it appеars that thе mitoсhondria-thе powеr plants of еukaryotiс сеlls-arе dеsсеndеd from thе suЬgroup protеoЬaсtеria. (Еsсheriсhiа сoli is today'swеll-known protеoЬaсtеria; it livеs in thе guts of all mammals, inсluding humans.) Thе сhloroplasts of plants, thosе сеllular struсturеs that drive photosynthеsis,also appеar to havе a symЬiotiс origin. Thus еukaryotеs arе truly сhimеras, whiсh arе thе orgаnisms сarrying gеnеtiс instruсtions from many diffеrеnt typеs of anсеstors. Thе symbiotiс rеlationships that formеd thе еukaryotеs havе есhoеs in thе сomplеx rеlationships that modеrn еukaгyotеs havе with modеrn Ьaсtеria. Baсtеriatoday arе ubiquitous and othеr organisms сannot livе without thеm. Мany plants dеpеnd on Ьaсtеria to еxtraсt thе nitrogеn from thе air so that thеy сan usе it thеmsеlvеs. Aiding this proсеss is thе aim of many artifiсial fеrtilizеrs,and it is wеll known that tоday аgriсulturalists arе working hard to modify plants gеnеtiсally so that, thanks to gеnеs transfеrrеd in from Ьaсtеria, thеy сan thеmsеlvеs сrеatе usaЬlе nitrogеn. Мammаls usе many Ьaсtеria in thеir stomaсhs and intеstinеs, usually сallеd gut flora, to digеst thеir food. Baсtеria in thеsе plaсеs also havе othеr funсtions, likе prеvеnting сеrtain disеasеsor stopping various potеntial allеrgiеs.Мorе gеnеrally,humans usе Ьaсtеria for thеir own еnds, as in fеrmеntation. Todаy, Ьaсtеria arе еvеn usеdin сlеaning up oil spills. Unfortunatеly, it is oftеn diffiсult to livе with Ьaсtеria. Many disеasеs of animаls(еspесiallyhumans) and of plants arе duе to Ьaсtеria.Rеvеrting Ьaсk to history,tooth dесay is duе primarily to four kinds of Ьaсtеria found in thе mouth:Streptoсoссus sаnguis, S' sobrinus, S' mitis, and S. mцtап.s.Othеr un. plеasantЬaсtеrial disеasesin humans arе lеprosy (Hansеn's disеasе),сausеd Ьу Муcobасterium leprаe; whooping сough, сausеd Ьу Bordеtеllа pеrtussis; сholеra,сausеd Ьу Vibrio сholorае; and tuЬеrсulosis' сausеd Ьу Муcobасtеrium tubеrсцlosis. Rесеntly, pеptiс ulсеrs wеrе found to Ье сausеd Ьy

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Bаеr Heliсobаctеr pуlori. Сеrtain intеstinal disеasеs, suсh as Crohn's disеasе, aге thought to Ье thе rеsult of thе Ьody's failurе tо rесognizе its own Ьaсtеrial gut symЬionts. Baсtеria arе known to Ье rapid еvolvеrs. Pеrfесt ехamplеs of natural sеlесtion in aсtion, thеy gеnеtiсally put up Ьarriеrs against human prеvеntativе mеasurеs quiсkly. Antibiotiсs, еspесially pеniсillin, wеге thе grеat mеdiсal disсovеriеs of thе twеntiеth сеntury Ьесausе thеy еntirеly dеstroyеd.targеtеd baсtеria without affесting thе human host. Unfortunatеly' thanks to mutation, high ratеs of rеproduсtion, and horizontal gеnе transfеr, Ьaсtеria dеvеlop natural rеsistanсеs to antiЬiotiсs. For instanсе, almost as soon as .War pеniсillin was introduсеd during !7orld II' it was found t'Ьat Stаphуlocoсctts сturеиswas dеvеloping gеnе-dirесtеd Ьioсhеmiсal mеthods of dеfеnsе. Thе samе is truе of othеr Ьaсtеria. Notoriously' vеnеrеal disеаsе usеd to Ье сurеd with just onе shot of pеniсillin. Now it takеs a сoсktail of drugs to сomЬat it. It doеs not hеlp that humans do many things that еnсourаgеrеsistanсе dеvеlopmеnt' suсh as whеn prostitutеskееp thеmsеlvеson сontinuous' rеlativеly low dosеs of antiЬiotiсs. Baсtеria sееm to find this a сhallеngе, find. ing ways to survivе and thrivе. Thе сapaЬility of rapid еvolution in Ьaсtеria also prеsеnts a сhallеngе for .Wе undеrstanding thеir еarliеst еvolutionary history. arе attеmpting to rеtraсе еvеnts that bеgan at thе dawn of lifе, сhanging rapidly and through mесhanisms likе thе horizontal transfеr of gеnеs with signaturеs not еasy to traсе. ]t4odеrn advanсеs in molесular Ьiology arе сhanging our undеrstand. ing, and thе study of Ьaсtеrial еvolution is among thе most сhallеnging and ехсiting topiсs in modеrn еvolutionary Ьiology. в|вLIoGRAPHY Dеaсon,l. Thе МicrobiаI World. http://hеlios.Ьto.еd.aс.uk/Ьtо/miсroЬеs/. Howland, J. 2000. The SurprisiпgArсhаеа.Nеw York: oхford UnivеrsityPrеss. Univеrsityof Сalifornia Мusеum of Рalеontologу'Iпtrodисtiсlпto tbe Аrсhаеа. -J.Т' апd М.R. http://www.uсmp.Ьеrkеlеy.еdu/arсhaеa/arсhаеa.html/.

Baеr, Karl Еrnst von (1792_1876) Karl Еrnst von Baеr was pеrhaps thе most еminеnt morphologist and еmЬryologist of his day. Hе was Ьorn in Еstonia to a Gеrman noЬle family. Hе attеndеd thе nеw univеrsity in Dorpat and сontinuеd mеdiсal studiеs in Bеrlin and Viеnna. Мorе intеrеstеd in thе thеorеtiсal aspесts of thе sсiеnсе, hе pursuеd postdoсtoral study at.!(iirzЬurg (1815), whеrе thе rеsidual influеnсеof Friеdriсh Sсhеlling (-]"775_1854)сould still Ье fеlt, transmittеd thrоugh thе gеnial hands of Ignaz Dбllingеr (1770_184I). In 1817 hе movеd to KбnigsЬеrg to Ьесomе assistant to Karl F-riеdriсh Burdaсh (1776-1847). Baеr's soЬеr еxpеrimеntal approaсh to anatomy lеd him to shеd muсh of his еarliеr еnthusiasm for a morе romаntiс and aеsthеtiс intеrprеtation of natural phе. nomеna. In 1826 hе Ьеgan studying thе foгmation of thе vеrtеЬratе еmЬryo and initially сonсеrnеd himsеlf with thе origin оf thе еgg in mammals' whiсh

had Ьееn assumеd to i with а fluid еmittеd Ь. his dirесtor's pеt dog еry with whiсh his n; еmЬryologiсal studiе tш i сk еlипgsgеs сh iсh tt 1 8 2 8 а n d 1 8 3 7 .I n 1 t dеrtook various kind Russian Еmpirе. In t though also a dесidеd Likе Gеorgеs Сuviе Ье sеparatеd into fou urсhins), thе mollusса and сraЬs), аnd thе vr pitulation thеory-thс through morphologiс: ganisms lowеr in thе h imal ехеmplifiеd fror Urfсlrm of that partiс ..isаlrеady at tJ sеrtеd, man fеtus, hе hеld, w. form of a gеnеralizеd and finally a partiсul fronr thе gеnеral to t} foге, nеvеr assumеdtl Dеspitе Baеr's rеjе within a givеn arсhе еarliеr stagеsof еmЬr attriЬutеd to Louis A1 tlе еmЬryos that hе birds' or vеry young thеsе animаls is quitе Ьгyos. But еvеn if thе indiсatе anything; siп of Ьirds, as wеll аs th mеntal form'' (l828_

Though hе Ьесam many Gеrmаn morpl сonrrесtеd him with t ratеd Ьy Sсhеlling.Hr amplе, that thе arсhе guidеd thе сrеaturе' ..t mal,'' hе dесlarеd, govеrns its еntirе dеv Baеr oЬjесtеd to t rootеd in Gеrman Ьiс

Bаer iеs'suсh as Сrohn's disеasе,arе o rесognizеits own Ьасtеrial gut еrfесtехaInplеsof natuгal sеlесе r s a g a i n s th u m а n p r е v е n t a t i v е niсillin, wеге thе grеat mеdiсal thеy еntirely dеstroyеd targеtеd Unfortun:ltеly, thаnks to lnuta)ntal gеnе transfеr, Ьaсtеria dеrr instanсе, alrnost as soon as : lI, it was found that StаpЬуloЬioсhеmiсаlmеthods of dеfеnsе. .rsly,vеnеrеaldisеasеr'rsеdto bе l it takеs a сoсktаil of drugs to r а n yt h i n g st h а t е n с o u r a g еr е s i s k е е pr h е m s е l v еos n с o n t i n u o u s ' эеm to find this a сhallеngе' find:ria also prеsеntsa сhallеngе for s t o r y .W е a г е a t t е m p t i n gt o r е :, сharrrging rapidly and thr
э.еd.aс. uk/Ьto/miсroЬеs/. ,York: oxfoгd UnivеrsityPrеss. у, lпtroduсtioпto thе Аrсhаеа' raеa.html/. -.I .T. аnd М.R.

minеnt moгpholоgist and еmbry'o a Gеrman nоЬlе familу. Hе atntinuеd пrеdiсal studiеs in Bеrlin сal aspесtsof thе sсiеnсе,hе pur). whеrе thе rеsidual inflцеnсе of Ье fеlt, transmittеd through thе 1 ) .I n 1 8 1 7 h е m o v е d t o K б n i g s :h Burdaсh (1776-1847). Baеr's d him to shеd rrruсh of his еarliеr :tiс intеrprеtationof natural phе. .mationof thе vеrtеbratе еmЬryo ;in of thе еgg in mаmmals' whiсh

had Ьееrrassumеd to Ье idеntifiеd with thе Graafian folliсlеs of thе ovirriеs or with а fluid еmittеd Ь,vtlrе folliсlеs. Irrthе sprir-rg of thе nехt yеar hе saсrifiсеd his dirесtor'spеt dog аnd loсatеd minutе yеllow еggs in its folliсlеs' a disсovеry with ц,|riсlrhis.rrzrmе would lrеrrсеfoгtlrЬе assoсiatеd.Hе сontirruеd his еmЬryolфiсal studiеs, puЬlishing thе two parts оf his mastеrwork, Die Еntшiсkеlипgsgеsсlliсhtеder Тhiеrе (Тhе dеvеlopmеnralhistory of animals), in 1828 and l837. In 18.34hе ассеptеd a сhair in St. PеtеrsЬurg,whеrе hе undertсlсlkvaгious kinds of апthropologiсal and еthnographiс studiеs for thе Russian Еrnpirе' In his latеr yеars hе Ьесamе a modеratе еvolutionist' althor"rgh also a dесidеd opponеnt of Darwiniаrr thеory. l-ikе GеorgеsСuviеr (1769-118З2), Baеr hеld that thе anirnаl kingdom сould Ье sеparatеdintсl lЪur distiIrсtarсhеtypеs:thе radiata (е.g.,salrfish and sеа urсhins),thе mollusсa (е.g.,сlams and oсtopusеs)'thе artiсцlata (е.g.,insесts аnd сraЬs),and thе vегtеЬr.lta(е.g.'fislr аnd humarr bеings).Hе dеniеd rесapitulation thеory-thе idеa tlrat thе еmЬryos of morе соmplех аnimals passеd through nrorphologiсal stagеsсoпrparaЬlе with thosе of thе adult forrns of or. ganisms lorvеr in thе hiеrarсhy of lifе. Hе maintainеd that thе еmЬryo of an аnimal еxеmplifiеd from thе Ьеginning of its gеstation only thе arсhеtypе or Urform of that partiсr"rlаrorganisnl. ..Thе еmlrryo of thе vеrtеЬratе,'' hе ass е r t е d.,. i sa l r е a d ya t t l r еЬ е g i n n i n ga v е r t е Ь r a t е '('1 8 2 8 _ 18 З 7 , 1 : 2 2 0 ) . S o a h u man fеtus,Ье hеld, w<>uld movе through stagеsin whiсh it would takе on thе forпr of a gеnеralizеdvеrtеЬratе'a gеnеrirlizеdmamпral, a gеnеralizеd primatе, and finally a partiсulaг humаn Ьеing. Tlrе fоrm of thе growing fеtus movеd fгom thе gеnеrаl to thе spесifiс. Thе human еmЬryo in its еarly stagеs' thеrе_ forе,nеvеr assumеdthе mаtuге form of arr invеrtеЬratеor of a fish. Dеspitе Bаеr,s rеiесtion сlf striсt rесapitulation, hе did allow thаt spесiеs within a givеn arсhеtypе displayеd virtually iс]еntiсalstruсturеs during thе еarliеrstаgеsof еmЬryogеnеsis.In a famоus passagеthat Darwin mistakеnly аttriЬutеdto Loшis Agаssiz (1s07-187З)' Baеr mеntionеd that hе had two littlе еmЬryos that hе hаd fсlrgоttеn to laЬеl: ..Thеy might Ье lizаrds, small birds' or vеry young lrrаmmаIs.Тhе foгmation of thе hеаds аnd trunks in thеsеanin.ralsis quitе similar. Thе ехtrеrnitiеsаrе not yеt prеsеntin thеsе.еmbryos.Brrtеl,еnif thеу wеrе in thе fiгst stаgеsof dеvеlopmеnt,thе1.would not indiсatеanything; sinсе thе fееt of lizards and mammals, thе wings and fееt of Ьirds, аs l,l,еllаs thе l.randsand tЪеto[ mеn dеvеlop fгorrr thе sаmе fundam е n t a lf o r m ' ' ( 1 8 2 8 _ 18 3 7 ' I : 2 2 1 ) . Though hе Ьесаmе wаrv of thе romаntiс Nаturpbilсlsophiе ехhiЬitеd Ьy manv Gеrman morpl-rolсlgists, Baеr rеtainеd сеrtain mеtaphysiсal idеas that сonnесtеdlrirт ш.itlrtlrе tгaditiсlnсlf transсеndеntalidеаlism thаt was inauguratеdЬy Sсhеlling.Hе sееmsnеvеr to havе aЬandonеd thе сonviсtion, for ехanrplе,tlrаt thе :rrсhеtypеof thе organism, as а kind of ехtraphysiсal еntity' guidеd thе сrеaturе's morphologiсal dеvеlopmеnt. ..Thе typе of еvеry animаl,'' hе dесlarеd, ..Ьtlth Ьесomеs fixеd in thе епrЬryo at thе Ьеginning and g o v е r n si t s е n t i r еd е v е l o p m е n t ,(' 18 2 8 - 1 8З 7 , 1 : 2 2 О ) ' Baеr oЬjесtеd to rlrе transmutаtionzrlthеory th21tWas quiсkiy Ьесoming rootеdin Gеrmаn Ьiology. Hе undеrstсltldthat idеas of rесapitulation and of

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Bаеr spесiеs еvolцtion gavе sеduсtivе suссor to onе anothеr) and hе firmly opposеd thеm Ьoth: Onе gradually lеarnеd to think of thе diffеrеnt animal forms as dеvеlop' ing out of onе anothеr-and thеn shortly to forgеt that this mеramorphosis was only a modе of сonсеption. Fortifiеd Ьy thе faсt,thаt in thе oldеst layеrs of thе еarth no rеmains from vеrtеЬratеs Wеrе to Ье found, naturalists Ьеliеvеd thеy сould provе that suсh unfolding of thе diffеrеnt animal forms was historiсally groundеd. Thеy thеn rеlatеd with сomplеtе sеriousnеssand in dеtail how suсh forms arosе from onе anothеr. Nothing was еasiеr. A fish thаt swam upon thе iand wishеd to go for a walk, Ьut сould not usе its fins. Thе fins shrunk in Ьrеadth from want of ехеrсisе and grеw in lеngth. This wеnt on through gеnеrations for a сouplе of сеnturiеs. So it is no wondеr that сlut of fins fееt havе finally еmеrgеd.(1828_1837, |: 200) Thе сommunity of Gеrman zoologists livеd along sеvеral сonсеptual fissurеs. Somе, likе thе rеdouЬtaЬlе Baеr, rеjесtеdthе notion of rесapitulation and thе supportivе doсtrinе of spесiеs dеsсеnt. Gеorg Hеinriсh Bronn (1800_1862)' Darwin's first Gеrman translator, thought that spесiеs progrеssivеlyappеarеd on thе еarth ovеr vast pеriods of timе aссording to a divinе plan. Hе rесognizеd that еmЬryoniс dеvеlopmеnt Ьorе a strong analogy to thе morphologiсal dеvеlopmеnt of spесiеs;Ьut pеrhaps fеaring thе сonsе. quеnсеs of thе rесapitulational idеa, hе strеssеdthе analogiсal сharaсtеr of thе parallеl and rеaffirmеd thе Ьoundаriеs of еmЬryogеnеsisthat Baеr had еstaЬlishеd. Othеrs, likе thе romantiс Lorеnz Оkеn (1779_1s51) and thе aеsthеtiсally drivеn Gеorg Gustav Сarus (1789_1869), unhеsitatingly advanсеd thе thеory of thе аrсhеtypе and its attеndant notion of rесаpitulation, whilе thе еmЬryоlogistsFriеdriсh Tiеdеmann (1781_1861) and Johann Friеdriсh Mесkеl (1781*1833),undеr thе influеnсеof Jеan-BaptistеLamarсk, aссеptеd thе doсtrinе of spесiеstransformation. Darwin adoptеd rесapitulation thеory dеspitе Bаеr's striсturеs.Hе agrееd that thе еmЬryo passеd from a gеnеralizеd to a morе partiсulaг morphologiсal statе. Hе simply hеld that thе phylogеnеtiс anсеstor was of a gеnеral typе-for instanсе, that thе еvolutionary progеnitor of man was a gеnеralizеdvеrtеЬratеwhosе form would Ье rесapitulatеd in thе human еmЬryo. ..Thus thе еmЬryo,'' Darwin oЬsеrvеd in Оп the origin of Speсies (1859, 3З8)' ..сomеsto Ье lеft as a sort of piсturе, prеsеrvеd by naturе, оf thе anсiеnt and lеss modifiеd сondition of еaсh animal.'' By thе еarly 1870s thе еvolutiоnary thеsis had swеpt through Еuropе' lеaving only thе most rесalсitrant in its wakе. Baеr undеrstood thаt thе kind of еmpiriсal еvidеnсе Darwin сitеd, еspесially from Ьiogеography and palеontology, pointеd in only onе dirесtion, Ьut hе would not сountеnanсе Dar' win's dеviсеs of spесiеs сhangе-сhanсе variation and natural sеlесtion, whiсh сould not aссount for thе tеlеologiсal struсturе of organisms. If Darwinism wеrе сorrесt, intеrmеdiatе forms should bе produсеd Ьy sеlесtion, Ьut nonе wеrе found. Сhanсе variation. whiсh thе thеorу assumеs.should

fluсtuatе in both pс advanсе. N4orеovеr swampеd out. Baеr plants appеarеd sud diсatеd, and thаt in transitions within еа mammals-all arсhi thе prеsеnt timе wa tеntativеly Ьut hopе ,,for a truе undеrst i n t е l l i g е n с е ' ,( \ 8 7 6 '

еvolutionists and al Baеr.

в|вLIoGRAP1

Baеr' K. Е. von. 1828 Rе|leхioп.2 vo|s \876. UеbеrI Nаtиrшissensсh 1 1 8 8 6119 8 6 еd Oppеnhеimеr, Publiсations. D a r w i n ,С . 1 8 5 9 .o п ,l'96 oppеnhеimеr,I. СamЬridgе,МА: Riсhards, R. 1992.Th IdеologiсаlRесoп Prеss.

Bartholomеw, с Sсhmidt-Niеlsе

Although not mains Knut Sсhmidt-Niеls tion. Bartholomеw l pionееrеd thе studу adaptations to spе thеy dеvеlopеd askе amplе' onе of Sсhm watеr and salt balar among spесiеs that сhеmiсal propеrtiеs variaЬlеs. Onе of Ba rows living in salt n a сapaЬility not sha salt marshеs. Thе сt inspirеd, rеvеal how

])аrtЬoIomеtaапd Sсbmidt-NiеIsеn 44З aгlothеr' and hе firпrly opt аnimal forms as dеvеlopforgеt that this mеtamorfiеd Ь,vthе faсt that in thе tеЬrаtеswеге to Ье found, r unfo|dingof thе diftЪrеnt 3y thеn rеlatеd with сorrr_ ts аrosе from onе anothеr. hе land wishеd to go for a rk in Ьrеadthfrom want оf lugh gеnеrationsfor a сourt of fins fееt havе finally

fluсtuatе in botlr positivе and nеgativе dirесtions' thwartirrg еvolutionary advanсе. Morеovеr, sеlесtеd traits would, through random mating, Ье swampеd out. Baеr rathеr suppоsed that thе grеat сlassеs of animals and plants appеarеd suddеnly in anсiеnt timеs, as thе gap-riddеn fossil rесord indiсatеd, and that intеrtral,tеlеologiсal laws lrad to dеtеrminе еvolutionary tгаrrsitionswithin еaсh of thе largеr groups of arrimals-fish' rеptilеs, Ьirds' mаmmals-all..arсhing toward partiсLllаr goаrlsand diminishing iгt ptlwеr as thе prеsеnt timе .wzlsapproaсhеd. Bаеr offеrеd his spесifiс hypothеsis only tеntativеly Ьut hopеd that hе had awаkеnеd in thе rеadеr rесognition that ..for a truе undеrstanding of naturе' Wе сannot dispеnsе with a govеrning i n t е l l i g е n с е ' (' 1 8 7 6 , 2 : 4 7 З | . R е m е m b е r i n g h i s е a r l y w o r k i n е m Ь r y o l o g y , еvolutionists and antiеvolutionists alikе rеvеrеd thе яrеat Kагl Еrnst von Baеr. в|вLIoGRAPHY

zrlongsеvеralсonсеptшаl fis_ thе notion of rесapitulation эnt. Gеorg Hеinriсh Bronn 'r' thought that spесiеs pгolds of timе aссording to a dipmепt Ьoге a strong anаlogy r.rtpегhapsfеaring thе сonsе_ c thе analogiсal сharасtеr of :mbryogеnеsisthat Baеr had okеn (|779_1851) and thе i9_1869|, unhеsitatingly adеndant notion of rесapitular n n ( 1 7 8 1 - 1 8 6 1 )a n d J o h a n n ,rсеof Jеan_BaptistеLamarсk, . Darwin adoptеd rесapitula_ thаt thе еmЬryo passеd from :al statе.Hе simply hеld that -._for instanсе, that thе еvo/еrtеЬratеwhosе form would rs thе еmЬryo,'' Darwin oЬ..сomеs Ье lеft as а sort of to rd lеss modifiеd сondition of l swеptthгough Еuropе, lеav: undеrstoodthat thе kind of m Ьiogеographyand palеonwould not сountеnanсе Daration and naturаl sеlесtion, ruсturеof orgаnisn-rs.If Darld Ье produсеd Ьy sе|есtion, r thе thеory assumеs' should

und dеr Thiеrе:Bеtlbctсhtuпg Baеr,K. Е. von. 1828-1837' Еппaiсkeluпgsgеsсhiсhtе Re|leхioп.2 vols. KonigsЬеrg:Borntrigеr. 1876. UеbеrDаrшiпs Lеhrе.InЬis Stи,liепаиf dem Gеbiеtеdеr Nаtиrtuissепsсhаfteп, 2 vоls.' 2: 235_480. St. PеtеrsЬurg:Sсhmitzdorff. [1886]1986.Autobiogrаphуof Dr. Kаrl Еrпst uoп Bаеr.2nd еd.J' еd..;H' Sсhnеidеr' trans.Nеlv York: SсiеnсеHistory Oppеnhеimеr' Publiсations. Dаrwin,с. 18.59.Оп thе Оrigin of Spесiсs.Lorrdon:John Мurrа1'. opреnhеimеr,I.|967. Еssауsiп thе Нistсlr1,o| Еmbrуologуапd Biсllсlgу. СamЬridgе,МA: МIT Prеss. -Гhе Меапiпg сlf Еuolutiспt:Тhе МorpbсtlogiсаlСoпstruсtiсlпапd Riсhards'R. 1992. сlf Dаrшiп's Thесlrу.Сhiсаgo:Univеrsit1'of Сhiсago IdeсllogiсаlRесrlпstruсtiсlп -R./.R. Prеss.

Bartholоmещ Gеorge (ь. |91.9),and Sсhmidt-Niеlsеn,Knut (\9I5 -2007 ) Although not mainstrеam еvolutionаry Ьiologists,Gеorgе Bartholomеw аnd Knut Sсhmidt-Niеlsеn Wеrе еnormously influеntial for thе study of adaptation. Bartholomеw аrrd Sсhmidt-Niеlsеn,with thеir сollеaguеsand studеnts, pionееrеd thе study of physiologiсal and Ьioсhеmiсal traits of animals as adaptatiоns to spесifiс еnvironmеntal сonditions. Thе rеsеarсh programs thеy dеvеlopеdаskеd how animals funсriсlrrirr сhallеngirrgsitr:arions.For ехprojесts zrskеdhow dеsеrt аrrinrаlsmаintain amplе,onе of Sсhrrridt_Niеlsеn,s Thеsе typеs of quеstions lеd to Ьroadеr сomparisons watеr and salt Ьalar-rсе. among spесiеs that showеd how wеll diffеrеnсеsin physiolоgiсal and bioсhеmiсal propеrtiеs wеrе matсhеd to diffегеnсеs in partiсular еnr,ironmеntal variaЬlеs.onе of Bагtholomеw'sproiесts ех:rminеdhow populаtiorrsof sparrows living in salt nrarshеswеrе aЬlе to obtain watеr Ьy drinking sеawatеr' а сapаЬility not shilrеd in populations of tЬе sanrеspесiеsthat do llot livе in salt marshеs.Thе сumulаtivе rеsults of thеir work, along with thе work thеy inspirеd,rеvеal how wеll thе funсtional svstеmsof diffеrеnt spесiеs'and еvеn

444

Bаtеs diffеrеnt populаtions of thе sairrеspесiеs'lravе Ьееn moldеd tO mееt diffеrеnt еnvironmеntal сirсumstаnсеs'prеsеlltinga formidaЬlе сasе for thе powеr and p r е с i s i t l no f a d a p г a r i o n . Bаrtholomеw аnd Sсhmidt-Niеlsеn wеrе сOntеnrporariеs;Barthоloпrеw rесеivеd his PhD in 1947 fгom Gеorgе Clarkе arrd Sсhrnidt-Niеlsеnrесеivеdhis DPhil from NoЬеl Laurеatе August Кrogh tn 1946' For ovеr 40 yеars thеy dirесtеd сritiсal studiеs in plrysiology that wеrе аnimatеd Ьy есologiсаl and еvоlutionary pеrspесtivеsand thе сonviсtion thаt аnimаls wеrе funсtionally intеgratеd,mеaning onе hаd to undеrstand thе еndreЪnirnаl in its еnvironmеnt. Both sсiеntistsstudiеd a widе rangе of proЬlеms in a divеrsity of animаls in many еnvironmеnts. Barthоlomеw's Ьеst-known studiеs rеvolvеd around tеmpеr.aturеrеgulation and еnеrgy mеtаrЬolism'topiсs that appliеd to survival in еxtrеmе сlimatеs, hiЬеrnation, anс] thе еnеrg'еtiсsof 1lying in Ьirds. Sсhmidt-Niеlsеn is Ьеst rеmеmЬеrеdfor his ехaminations of watеr and sаlt Ь:rlirnсеin с]еsеrtаnd rrrаrinеaninrals аs rvеll аs his latеr work оn thе sсaling of mеtаrЬoliсratеs and thе еnеrgеtiссosts of loсomсltion in tеrrеstrial vеrtеЬratеs.Еaсh is wеll known among gеnеrati()nsof studеntsfor their studiеs of сurious or сharismаtiс proЬlеms, suсh as Bzrrtholomеw'ssсrutiny of thе ad:rptationsto diving in nlarinе iguаnas and Sсhmidt-Niеlsеn'sstudy of thе сamеl's adaptation to dеsеrt сonditions. Bartholomеw and Sсhmidt-Niеlsеn Ьoth wеrе rеnownеd сlassroom tеaсhеrs,mеntors' and writеrs; Bartholomеw has ovеr 1,000 irrtеllесtualdеsсеtrdants(studеntszlnd studеnts of studеnts) and Sсhmidt-Niеlsеn'stехtЬooks arе among tlrе most popular аnd appеaling сollеgе tеxts еvеr writtеn. Еaсh influеnсеd Ьiologists far Ьеyond his irnmеdiatе disсiplinе' atld еaсh wаs influеntial in Ьuilding two of thе Ьеst zoology dеpartmеnts in tЬе Unitеd Statеs,BаrtЬolomеrv аt UСLA and Sсhmidt-Niеlsеn аt Dukе Univегsitу. Thе intеllесtuаl lеgaсy usSсiепtist. -].T, Washington'DС: IslandPrеss.

Batеs, Hеnry Waltеr (L825_Т892) Britislr naturalist Неnry Waltеr Batеs is сrеditеd with thе disсovеry of protесtivе mimiсrу. Today, thе sсеnario irr whiсh an tlrganisrr-l rеsеmЬlеsаn unrеlatеd' unpalataЬlеspесiеsis сallеd Bаtеsian rтimiсгy. Although not thе first tо notiсе sharеd appеaranсеsсrf spесiеs,Batеs rеinvеntеd thе suЬjесt in 1862.

F{е turnеd сollесttlгs сlassiс ехаmplе, and ral sеlесtionin aсtior As wаs сomnlon manufaсturir-rgсity .

еduсatеd hoЬЬyist. J puЬlishing from а yс .Wallасе, frеd Russеl tеrеst as wеll in thе rеad widеly on spесi naturаl law. Thеir rt

work in Brazll. I n 1 8 4 8 , B a t е sa n d to sеll ехotiс sPесim ссlllесtingpaid tlrеiг addrеss thе naturе at spеnt thе nеxt ninе y his spесimеnsаnd nс еxpеrt on sеvеral gr. Ьold and talеntеdеx. Batеs'sfiеldwork s its аttеrrtionto thе r( that Batеs and Wallа origin of spесiеs.Up еnсе irr а sеriеs
есologiсal obsеrvаti and ]]atеsЬесаtnеan origiп of Speсiеs. А distriЬution of insес dеnсе of еvOlutiona winism in naturе, wl stunrring support bе p for suсh a strikir"rg

Bаtеs Wаs a rеspе еtiеs, Ьut his сarееr vаdе thе old guard. British Мusеr'rmсlf ] origirrsand laсk сlf s сamе asSistantsесrе sponsiЬlе fсrтthе or1 to pr()duсеa ltlng st for othеr сollесtors Alorrg with mirni Thе Nаturаlist tп tl

immеdiatе suссеss' s i g h t s ,a n d s k i l l Г t l lр

Bаtеs е Ьееnmoldеd to mееt diffеrеrrt :midaЬlесasе for thе powеr and Barthol omеW rе)Irtешporаriеs; nd Sсhmidt-Niеlsеnrесеivеd his 1946.bсlrovег 40 yеаrs thеy di:rе аnimatеd Ьy есologiсаl and that animals wеrе funсtionally г h ее r r t i r еa n i m . r li r l i t s е n v i r o n f prоЬlеmsin a divеrsity of ani's Ьеst-known studiеs геvolvеd topiсs that appliеd to еtaЬ
сontгiЬutionsto intеgrativеаnd 4 5 : Z|9 _2-30. ,.l|L|tiL' е B iolс>gу 1еmoirsof а С'uriсlиs Sсiепtist.

-1.r.

litеd with thе disсovеry of protесt an organism rеsеmЬlеs an unrеnrimiсry. Although not tЬе first to s rеinvеntеdthе suЬiесt tn 1862'

Hе turnеd сollесtoгs' odditiеs into i1 powеrful сasе study. Mimiсr1'Ьeсamе :l сlаssiсехamplе, and onе of thе most popular tехtЬook iIlustrations,of natural sеlесtionin aсtion. As w:rs сommon in Viсtorian Еngland, tl,rеyoung Bаtеs' a сlеrk in thе nranufасtuгingсity сlf Lеiсеstеr, pursuеd natural lristory as a largеly sеlfеduсatеd hоЬЬyist. Не was arr aпrЬitious it-lsесtсollесtоr and taхonomist, puЬlishing fronr a yollng agе in natural history iournals. WitЬ his friеnd Alfrеd RLrssеl!7allaсе, hе turnеd to pгofеssional сollесting. Thеy sЬarеd аn in_ tеrеst as wеll in tl1е thеorеtiсаl quеstions Ьеing raisеd in thе 1840s. Both rеad rvidеly on spесiеsяnd wеrе dгawn to еarly disсussiоnsof еvolution and natural law. Thеir rеading trf trаvеlеrs' ассollnts of thе tгopiсs lеd thеm to wоrk in Brazil. In 1848, Bаtеs arld \WallaсеЬеgan an ехploration of thе Amazon, arrаngiлg to sеll еxotiс spесimеnsto сollесtors through an agеnt in London. Although сollесting pLridthеir way' thеy hopеd tсl Ьe aЬlе to tlsе thеir oЬsеrvationsto addгеsstlrе natцге and oгigin of spесiеs.Goir-rgsеparatеwаys in l850, Batеs spеnt thе nеxt trinе yеars аlong tlrе Arnаzсll-l.Hе Ьесirmеwеll known through his spесimеnsalrd nоtеs оn Ьеhаvior and distriЬution.Knor,vrras a taxonomiс еxреrt on sеvеrаl groups of insесts,Batеs аlso еаrnеd сrеdiЬility Ьy Ьеing а Ьold аnd talеntсd еxplorеr. Batеs'sfiеldwork stands out for its еаrlу intеrеstin distгibutionаl datа аnd its attеntion to thе rеlations of spесiеstсl еaсh othеr. Сorrеspondетrсеrеvеals .\Х/allaсе that Batеs and disсussеd аt lеngth how sr'rсhfaсts might addrеss thе origin of spесiеs.Uporr his rеturn to Еnglarrd in 1859, Batеs usеd his ехpеriеnсе in a sеriеs of taхonomiс plrpеrs and spесiеs notеs, whiсh inсludеd his есologiсal obsегvations.Сhаrlеs Darwirr aгguеd along linеs familiar to Batеs, and Batеs Ьесamеаrr immеdiаtе' еnthusiastiсDaгlvinian aftеr rеading Оп tbе Оrigilt of Spесiеs.Amtlng a sеriеs of papеrs on vаriatitln and gеographiсal distribution of insесts' Bаtеs dеvеlopеd thе саsе сlf mimеtiс Ьuttеrfliеsаs еvidеnсе of еvolutionary сhаngе' Не prсlvidеdthе dеtails of an ехamplе of Darwinism in naturе, whеrе thе strugglеfor еХistеnсеlеd to аdаptatioIl.It was a stunning support Ьесausе no prеvious natlrrаlistiс еxplanation hаd ехisгеd for suсh a strikir-rgglhеtromеnon' Batеs was a rеspесtеd naturalist arrd а mеmЬеr of tl-rеrnajor sсiеntifiс soсiеtiеs' Ьut his сarееr path shows that Darwinians did not always or еasily invаde thе old guard. Не appliеd Ьut failеd to sесurе a сtlrаtсrrialpost at thе British Мшsеum of Nаrural History. Hе wаs hampеrеd Ьy Ьis working-сlass origins and lасk of sосial сonnесtions' аs rvеll аs Ьy sсiеntifiсpolitiсs. Hе Ьесamе аssistantsесrеtar}'ofthе R
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Веrgsoп вIвLloGRAPHY Batеs' H. \и. 1863' Tbе Nаturаlist tп thе Riuеr Аmаzсllls. London: Jоhn Мurray. Сlodd, Е. [1863] 1892. Меmoir of thе author. In H. W. Bates,Thе Nаturаlist oп thе Riuеr Аmацllzs, хvii-lxхxiх. Rеprint еd. London:.|оlrn Murray. Мoon, |1.P. 1976. Hепrу Wаltеr tsсlсs ЛRS, 182.\-1892:Ехplorеr, Sсiепtistапd Dаrtuiпiап. I'еiсеstеr:LеiсеstегshirеN[Lrsеums.Art (]аllеriеs.and Rесoгds Sеrvlсе.

O'Нara, J. Е. 1995. Hеnry Waltеr Batсs-His lifе and сtlntriЬutiоnstо Ьiologу. -w.С.K' A r с h i u с st ' [ N а l t t r а I H i s l , ' r у 2 2 l .| g 5 _ 2 | 9

Bеrgson,Hеnri (1859_Т94|) Hеnri Bеrgson wаs a Frеnсh philosophеr who tаught for many yеars at thе Сollёgе dе Franсе. Hе had grеat influеnсе in his сountry and in Britain (his mothеr was Еnglish)'|n \927 hе was awardеd thе NoЬеl Prizе for litеraturе. Born of Jеwish pаrеnts' hе drеw сlosе to Сathоliсisnr Ьut rеfusеdto геpudiatе his hегitagе.Не diеd at the Ьеginnirrgof thе Viсhy rеgimе from а сold саtrght whilе waitillg for an idеntity с:rrс1' Не еntеrs thе story of еvolutiсln Ьесausе of hts l-'Еuсllиtioп сrёаtriсe, first puЬlishеd in |907 (Еnglish translation, Сrеаtiuе Еtlolцtioп, \911)' Bеrgson, who was influеnсеdЬy thе writings of НеrЬеrt Spеnсеr,always saw еvolution as an upward progrеssto humаnkind, Ьut hе did not 21gfее with thе Darwinian сlaim thаt a blind proсеss likе rrurturalsеlесtionсоuld do thе joЬ. Apаrt from anything еlsе, hе сould not sее how sеlесtiorrсould aссouпt foг thе fасt that somеtimеstwo quitе sеpаrаtеlinеs sееmеdto t:rkеthе samе еvolutionary d i г е с t i o n s ,a с q u i r i n gt h е s а m е i n n o v а t i o n s . This lеd Bеrgson to introduсе his famous, or notorious' notion of a vital spirit, what hе сallеd the ёlап uitаl (ёlапs uitсtuх in tlrе plural)' This is il forсе, rаthеr likе a lifе spirit of thе kind еndorsеd Ьy Aristotlе, that suрposеdly guidеs and drivеs thе еvolutional.y proсеss. Although Bеrgson аpproасhеd thе proЬlеm as ir philosophеr' hе found support froпr somе sсiеntists,notaЬly thе Gеrman еmЬryologist Hans Driеsсh, who as a rеsult of his ехpеrimеnts on dеvеloping organisms was likеwisе inсlinеd to a vitalist approaсh, сalling lris vеrsion of thе forсе t|teeпtelес|ll'. Vitаlism Was i1nathеmato most Ьi
-'l

stimulаting. His first Ьс wаs opеnly influеnсеd l lishеd his massivе ovеrv сludеd tlrat vitalism is г world as progrеssingup

this supposition. Tоday, fеw would op' еvolutionists who rеpud ..ordеr for frее,'' sесrеt mесhanistiс dеtеrminis сlеarly tlrе motivation Rеiпuеrtting thе Sасrеd' BlвLIoGRAPHY

Bеrgson,H. 1907.I-'ёuolu Huxlеy, l. S. \912. Thе lп UnivеrsityPrеss. | 9 4 2 .Е u o I t t t i ' ' n S. 2008. Rei,ll Katlffпrarn, Rеligioп. Nеw York: ] Rusе,M. 2О0З,Dаrtuiпаt N4A:Harvard Univеr

Biogеography

Biogеography is tо spaс tеrеstеd in thе есology ; gloЬе; thе palеontologr isms аs rеvеalеdthrсrug bеtwееn tlrе two bесаr'l Ь u t i o l - l so f o r g a n i s m si l r Thеге is a paradoх aЬ ontology. ,For thе laypе to thе point that many ; thing thzrt mаttеrs. For tгuth of еvolution, Ьiog Тhis wаs сеrtainly th еrеr of natural sеlесtion ing of his turn to еvolut diffеrеnt organisms suс( iсa. Thеn, famously, hе еnсountеrеd olr thе Gal diftЪгеnt' Hе сould not thе mainland and thеn t .DИhеn Dаrwin сamе t ( Speсiеs 1859)' palеont rесord, tlrе irpparеntaЬ

Biсlgеogrаpb1, 447

'|1аzo|1 s. l-ondon:John Мurrаy. H. \V. Batеs' The Nаturа|ist llп thе lon: John Мurray. i_I 8'92:Ехplсlrеr, Sсiеlttist апd ;, Art Gallеriеs,and Rесords Sеrаnd сontributionsto Ьiology.

_.w.С.K.

lo tаught fоr many yеars at thе Lhis сountry and in Britairr (his .d thе NtlЬеl Prizе for litеraturе. roliсismbut rеfusеdto rеpudiatе /iсhv rеgimе frorn a сold саught i Ьis L'Еuolиtirlп сrё,:ttriсe,first 'tiueЕllolиtiсlп, 1971 Bеrgson' )' :t Spеnсеr'always saw еvolution . did not аgrееwith thе Darwin:lесtionсould dсl thе joЬ. Apart :сtion сorrld ассoul1t for thе fасt еd to takе thе samе еvсllutiоnary . or notoriotrs'notion of а vitаl lиx irr thе plLlral).This is a forсе, d Ьy Aristtltlе' tlrat sr"rpposеdly Although Bеrgson аpproaсhеd cгt froпl soпlе sсiеlltists, nсltаЬly | o a 5 ; l г е s u l to f h i s е х p е r i m е n t s еd to a vitаlist аpprolrсh' саlling s, еspесiallyat thе Ьеginning of s LoеЬ wеrе еndеavoring to put с Ьasis.Thоsе attrасtеd to Bеrgoliс priеst and pаlеorrtologist, rсе-rеligionsyntЬеsis of thе еvo. thе Godhеаd, thе Orrrеga Point, nfluеnсеd Ьy Bеrgson Was thе rt, althoughproЬaЬly in his саsе as moге signifiсаnt. A third еn. Huхlеy, grandson of Thomas t Aidous Нuxlеy. Sеагсhing for НuхIеy found Bеrgson's idеas

stirnulating. His first Ьook, Thе lпdiuiduаl iп tЬe Апiпtаl Кiпgdсlm (1912), was opеnly influеnсеd Ьy Bеrgson's thinking. Bу 1942, whеn Huxlеy puЬlishеd his massivе ovеrviеw, Еuolutiott: Thе Мodеrп 31,пthеsis,hе sadly сorr. сludеd that vitalism is no Ьasis for sсiеnсе' Ьut hе still saw thе еvolutionary world аs progrеssingup to lrumankind, tгying to givе naгuгаlistiс bасking to this supposition. Today, fеw would oре.lly suЬsсгiЬе to an ёlап UitсIl'ьvt many suspесt that еvolutionistswho rеpudi.1tеstriсt Darwinism in favor of аltегnаtivеs,suсh as ..ordеr for frее,'' sесrеtly]harbor philosophiсal yеarnings against Ьlind аnd mесhanistiс dеtеrrninisnr, thе saпlе dislikе that nrоtivаtеd Bеrgsoll. Тlris is сlеarly thе motivation of thе mrrvеmеnt's lеadеr' Stuart Kauffп-ran, in his Rеinuепtiпg th e Sасred. вlBLloGRAPHY Bеrgson,11.1907. L'ёuolutioпсrёаtriсе.Paris:Alсan. Huхlеy,J. s. L912.Тhе lпdiuiduаliп thеАпimаl Кiпgdсlm.СamЬridgе:Сambгidgе UnivеrsitуРrеss. 1942.Еuolцtiсlп:Тhе Мodеrп Sупthеsis.London:Allеn and Unlvin. Kauf{man,S. 2008. RеiпuепtiпgtЬе Sасrеd:А Nеш Viеtuof Sсiепсе,Rеаsсп,апd Rеligiсlп.Nеw Yоrk: Basiс Bсloks. Rusе,M. 20О3,Dаrшiп аttdDеsigп:Does ЕuolutiсlпНаueа Purposе?СаmЬridgе, MA: Нarvаrd Univеrsity Prеss.

-М.R.

Biogеography Biogеographyis tо spасе as palеontology is to timе. Thе Ьiogеographеris intеrеstеdin tlrе ессllogyаnd еvolution сlf orgilnisms аs distributеd arouгrdthе gloЬе;thе palеontologistis intеrеstеdin thе есology and еvolution of organisms as rеvеaled through thе fossil rесord. Of сoursе, thеrе is muсh ovеrlap Ьеtwееnthе two ЬесausеЬoth arе intеrеstеdin how thе past influеnсеsdistri_ Ь u t i o n so f o r g a n i s m si n t h е p r е s е n t . Thеrе is a paradoх аЬout thе rеspесtivеstatusеsof Ьiogеogгаphyand palеontology. For thе laypеrson thinking aЬout еvolution, fossils сomе to mind' to thе point that n-ranypеoplе thirrk thаt thе fossil rесord is viгtually thе only thing that mattеrs' For thе еvolutionary Ьiolоgist sееking сonviсtion of thе truth of еvolution, Ьiogеographyis simply outstanding. This wаs сеrtаinly thе сasе for Сharlеs Darwin and irlso for thе сodisсov_ еrеrof natural sеlесtion'Alfrеd Russеl \Х/allaсе.In his autoЬiographу, in talking of his turn to еvolr-rtion, Dаrwin highlightеd thе wау in whiсh sirnilar Ьur diffеrеntorganisпrssuссееdеdеaсlr othеr as hе journеyеd down South Amеriсa. Thеn, filmously' lrе spokе of thе organisms (tortoisеsand Ьirds) tlrat lrе еnсountеrеdon thе Ga16pagosArсhipеlago irr thе Pасifiс: similar Ьut slightly diffеrеnt.Hе сould not sее how this сould Ье unlеss foundеrs had сomе fronr thе mainland and thеn еvolvеd as thеy sprеad Out aсross tЬе islanсlgroup. lfhеn Darwin саmе to prеsеnt lris thеory of еvсllution in Оп tbе Оrigiп of Spеciеs(1859), pаlеontologl. was somеWhаt proЬlеmatiс-gaps in thе fossil rесord,thе apparеnt aЬsеnсеof lifе forms Ьеforе thе СamЬrian, and so forth.

148

Biogеogrаphу But Ьiogеographу rvas a triumph. Paгtiсulariy important for Darwin was tlrе Way that thе inhaЬitants of islands arе so similaг to thе inhaЬitants of thеir сlosеst сontinеnts and not to thе inhаЬitants of сlthеr сontinеnts farthеr away. ..Thе most striking and impоrtаnt faсt for us in rеgard tсl thе inhaЬitаnts of isl:rrrds,is thеir аffinity to th
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Aftеr thе synthеtiс thе tory of Ьiogеography w. 1960s. Platе tесtoniс thе сontinеntal drift. It now that had сonсеrnеd thе n of lost сontinеnts Ьut of groups away from еaсh . thе samе timе gеology pothеses.A сlassiсеxam of Lуstrosаurиs. This hеr million yеars аgo' is fat, r havе bееn a world travс found in thе samе fossil (Southеast)Asia, and An faсt that, morе than 200 thеy wеrе part of Panga thе gеologiсal hypothеs ..Thе I in thе mаin еssay Thе dеvеlopmеnt of idеas about how to rес

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ortant for Darwin wаs thе to thе inhaЬitants of thеir I othеr сontinеnts farthеr us in rеgard to thе inhaЬirеst mаinland, without Ьесould Ье givеn of this faсt. pеlago,situatеd undег thе rеso{ Soutlr Amеriсa. Hеrе .hеunmistakеаЬlеstamp of сanсеof Ьiogеography. His l on tlrе ways in whiсh oгJobе. Не found that nеwly living organisms сlosе to inсidеnt Ьoth in spaсе and ' [ 1 8 7 1 ] ,2 5 ) . I n T b е G е o . се turnеd to issuеs in Ьiosurround islands as wеll as thе so-сallеd \7allaсе's linе еts o{ organisms, Asian and еlago, Ьеtwееn Bornеo and sast). olutionistswas ехaсtly how r а Ь l еt i m е r u n n i n g е х p е г i snails сould withstand salt е disсussеdhis work еxtеnlеn Ьy Darwin's сlcsе friеnd, uеdthаtplаnг distriЬuгions idgеs that havе now disapr part of a thеory of сlimatе' 3), whiсh supposеd that аl:еahvaysсhanging shapе Ьеtq

tlrе synthеtiс thеory in thе tology as most еffort was din sеlесtionthеory сamе Ьaсk o е v t l l u t i o n a 1 с1a u s a l i s s u е s . J сhangеin populations. Yеt ,. Partiсularly important was гnst Mayr. In his сlassiс Syssсussеdin dеtail issuеs to do .,rings of .hе importanсе of tеrЬrееdingpopulations of a :tivеlyistllatеd. Мayr arguеd of spесiеsin a gradual rathеr

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!Иallaсе's linе. Whеn hе was сollесting spесimеnsin thе Far Еast' Alfrеd Russеl !Иallaсеrealizedthat thеrе was a linе of sеparation ЬеtwееntЬе organisms of Asia and Australasiа.Hе disсussеdthis and othеr Ьiogеographiсalphеnomеna tnThе Gеogrаphiсаl Distributioп сlf Аnimаls (1876). Thе linе was first notеd Ьy a voyagеrwith Fеrdinand Мagеllan in 1521.

Aftеr thе synthеtiс thеory was wеll еstaЬlishеd, thе major еvеnt in thе history of Ьiogеography was thе сoming of platе tесtoniс thеory in thе еarly 1960s.Platе tесtoniс thеory offеrеd gеophysiсal еxplanations for thе idеa of сontinеntaldrift. It now Was possiЬlе to addrеss propеrly thе kinds of issuеs thathad сonсеrnеd thе ninеtееnth-сеnturyеvolutionists. It was not a quеstion of lost сontinеnts Ьut of сontinеnts that movе sidеways, сarrying onсе-joinеd groupsaway from еaсh othеr. Biogеography rесеivеd a powеrful tool and at thе samе timе gеology rесеivеd strong сonfirmation for its audaсious hypothеsеs.A сlassiс еxamplе of thе two-way proсеss is givеn Ьy thе distriЬution of Lуstrosаиrиs.This herЬivorous, mammal-likе reptilе, found morе than 200 million yеars ago' is fat, short, and squat. It is сеrtainly not a Ьеast that woцld havе Ьееn a world travеlеr' rеgularly swimming aсross oсеans. Today, it is foundin thе samе fossil dеposits (Lowеr Triassiс) on thе сontinеnts of Afriсa, (Southеast) Asia, and Antarсtiсa. This would Ье a miraсlе if it wеrе not for thе faсtthat, more than 200 milliоn yеars ago' all thrее сontinеnts toцсhеd whеn thеywеrе part of Pangaеa. Thе fossils support thе gеologiсal hypothеsis, and thеgеologiсalhypothеsis makеs sеnsеof thе fossil distriЬutions (sееFigurе 27 in thе main еssay ..Thе History of Еvolutionary Thought,' Ьy A4iсhaеl Rusе). Thе dеvеlopmеnt of platе tесtoniс thеory сoinсidеd with thе advеnt of idеаsaЬout how to rесonstfuсt spесiеs phylogеniеs using a sеt of еxpliсit

4s0

Biogеogrаphl rulеs, that is, idеas aЬout сladistiсs. Thе fusion сlf thеsе сonсеpts lеd to thе sсhool of viсarianсе Ьiogеography, artiсulatеd in thе 1981 volume Sуstemаtics апd Biogеogrаphу: Сlаdistiсs апd Viсаriапсe, еditеd Ьy Garеth Nеlson and Noгmаn Platniсk. Viсariarrсе Ьiogеographеrs, following Vеnеzuеlan Lеon Сroizat, еrrrphasizеdthе ir-nportanсеof sеaгсhingfсlr сomnron Ьiogеographiс pattеrns аmong unrеlatеd groups of organisms and diаgnсlsingthе rolе of gеolсlgiсal еvеnts in сrеating thosе pattегns. For еxamplе, a сlassiс viсarianсе analysis would idеntify thе сommon pattеrns of rangе limits and distriЬutions сrf gеnеtiс variatitlrrаmong s<-ruthеаstеrn U.S. fish spесiеs,pattеrns tied to Ьoundariеs аt major rivеrs' and diagnоsе thе formation of rivеrs and thе ехistеnсе of old еstuariеs аnd sеa сhаnrrеlsаs paramount еvеnts in brеaking onсе-сontiguous distгiЬutions and сгеating prеsеnt-day pattеrns. In сontrast, so-сallеd dispеrsal Ьiogеographеrs arguе that thе dispеrsal of spесiеs aсross Ьroad rangеs and сhangеs in dispеr:salratеs aсross major fеaturеs likе mountains or rivеrs arе morе impоrtant for prеsеnt-daypattеrns. Thе prсlpеr аnswеr is surеly a сomЬination of both viсariаnсе and dispеrszrl.Drift and tlrе suЬsеqr.rеnt Ьirrriеrsarе vеry imptrrtant.Howеvеr, no onе truly сan say that сontinеnt:rldrift is thе only kеy fасtor in organiс dispеrsals. Мassivе dispеrsals havе oссurrеd Ьеtwееn Nortlr and South Amегiсa as thе land links havе Ьееn еstaЬlishеdЬеtwееn thеm: thе ..Grеat Amеriсan Intеrсhangе'' (Маrshall et a\. \982 sее Figurе 26 in t-hеmain еssay ..Thе History of Еvolutionary Thought'' Ьy Nliсlraеl Rusе in this volumе). This is thе rеason marsupiаls, suсh as Opossllnls,еxist in Noгtlr Ar-rrеriсaand r
A mаjor Ьiogеograpl сal Ьiсllоgist RoЬеrt Мс Е d w а r d ( ) . W i l s o n 1| 9 t lands in tlrе sеа or oasе( гiving and spесiеs lеа funсtion of suсh fасroг r h е a r е а t l f t h е i s | a n di г сoIonizагitln аnd ехгinс сurvе' a mathеmatiсal fourrd in lt loс:rti
argr.ringthat аt сеrtаin1 еmpty r-riсhеsthat arе t rhаt mаtсh thе prеdiс ..Palеontology and thе Thе thесlrу of thе tахtlп s t г i k i n g е x t е r t s i o nI.n t l and, on еirсlr islаnd on i n i г r а lp o p u l а t i O nе x p e d е с l i n е l l n d е х t i n с t i o nr d i t i o n s . l t i s , i n е f Г е с te, proсеssеs rvith еvolutio tions аге сol1stаntlyoсс Ьy RoЬеrt RiсklеГsаnd this pгt-tссssin Wеst lnt ogy and еvolution сoul< T h е s е с o n n е с t i O n sа t standing Ьiogеographi t h а t a n i m l I s i n с r е a ь еi r pаttегn is еvidеnt in ц ехplаnations not in sir h е а t I n t l r ее f | е с t i v с | yl humidity, growing sеas Biogеography сontin с o n с е p г u i l lu n d е r p i n n

Biс-lgеogrаpbу, 4'\ 1 ion of tlrеsесonсеpts lеd to thе еd in thе 1981 volume Sуstеm,iапсе, еdited Ьy Garеth Nеlson raphеrs' fоllowing Vеnеzuеlan :sеarсhingfor сommon ЬiogеoI organisnrsand diagnosirrg thе )attеrns.For еxamplе, a сlassiс lon pattеrnsof rangе limits and l t h е а s t е r nU . S . f i s h s p е с i е s .p a t diagnosеthе foгmation of гivегs h а n n е l sа s p а r а m o u n tе v е n t si n [ сrеating prеsеnt-dаy pattеrns. 1еrs arguе thаt thе dispеrsal of rlispеrsаlrаtеs асross majoг fеa)rtаnt for prеsеnt_daypilttеrns. n of Ьoth r,iсarianсеand dispеr:ry important. Нowevеr, no onе .kеy faсtor in organiс dispеrsals. rlorth аnd South Amеriсa аs thе ..Grеat Amеriсаn IntеrLеm:thе ..Thе History i in thе main еssay in this volumе).This is thе rеaNorth Amеriсa and rodеnts apo g i с а lс h a n g е sl l a v е b е е n i n p а г t :wo fасtorsapart.) :еasingintеrеstis Ьеing takеn in lpulation gеnеtiсistsrеalizеd that thеir studiеs.A сlassiс сasе was tiа, a disеirsеin whiсh thе viсtim r Ь l r t h d a y .W h y d o е s i t o с с u r i n еrs?In onе dirесtion, it was pos'sion of a сеrtain kind of gеnе-and it was slrown that thе gеnе vhy thе сlistriЬution?\Х/hy in thе n s w е rс а m е Ь е с a u s еt h е g с n е s i n al immunity to malaria, and thе hosеarеaswith thе gеnе. In othеr l sеttingup Ьirrгiегsagainst infес. opulationgеnеtiсistswеrе ablе to ехaminе largе-sсalеpattеrns of еrns,biologistshavе Ьееn аblе to i n w h i с h а s p е с i е so r g r o u p o f al into its prеsеntrangе. Thеsе rе:aphy,rеpгеsеntthе modеrn vеr:хolorations.

A rrrаjor Ьiogеogгaplriсaiсссllogiсal tlrеory аppеarеd in thе 1960s. Thеorеtiсal Ьiologist Robеrt МaсArthur аnd insесt spесiirlisг(and futurе soсioЬiologist) Еdward o. !7ilson (1967) aгguеd that spесiеsnцmЬеrs on islands-whеthеr islаnds in thе sеa or Oasеsin thе dеsеrt-rеасh аn еquiliЬrium Ьепvееn spесiеsаrriving and spесiеs lеаving (pеrhirps through ехtinсtion). This Ьalanсе is ;-r fur-rсtiсln of suсlr fасtors as tlrе distаnсе сlf tlrе islаnd froпr tlrе rr-rainiandаnd of thе аrеa of thе islаnd itsеlf. In aсldition, МaсArthur and .й/ilson dеsсriЬеd how сolonization and ехtinсtion сould сornЬinе to gеnеratеthе so-сallеd spесiеs-arеa сurvе, a mathеmatiсal rеlationship thаt dеsсriЬеs how thе numЬеr of spесiеs fouпd ir-ra loсation inсгёаsеswith tlrе arеa (sоuaгеkilomеtеrs) of tl.latloсаtion. Spесiеs.аrеaсurvеЪhаd Ьееn t]еsсribеdin tlrе,p:rst,Ьut MaсArthur and $Иilson offеrеdthе first qtrаntitativеехplаnation for thе shapе оf thosе сurvеs. Thе есologiсal thеory inspiгеd a rеnaissanсеin Ьiogеography. Biologists usеd thе thеory trl rеintеrprеt arrсl unify sееmingly disparate pattеrns, fron-l thе distriЬution of spесiе'son isolаtеd mountаintops to thе сollsеquеnсеsof сrеаtinga fragnrеntеdhaЬitat fronr сontinuоus forеst.Thе аttеmpt to tеst thе сausal mесhanisnrsthat сould сrеate spесiеs.агеaсurvеs lеd to thе disсovеry of additional Ьiсlgеographiсpattеrns,suсh аs tlrе faсt that spесiеswith lаrgеr rаngеsаlso tеnd to lrаvе highеr population dеnsitiеs. Thеге havе ЬееrrsеvегаlinrportantеvolutiсlnilгyехtеIlsions
452

Birds rеsеrvеs and сontinuеs tO play а kеу rolе in tlrе сonfirmatoгy support tlf еvolutionary thеory. вlвLIoGRAPl.|Y Ьу thе siсk|е.се]ltrait аgainst suЬtеrtiаnпralаriaI Allison, A. С. 1954a. Protесtiсlt-t О. infесtion. B rit i s h М еdi саl J rl иrпа l 1,: 2.L) 1954ь. Thе distriЬutiоlrof thе siсklе-сеlltrait in l]аst Afriс:r arrd еlsеwhеrе and its appаrеnt rеlationship to thе inсiс]еnсеоf subtеrtianmаlагiэ. Тrаnsасtioпs o| tЬе Rrll,аl ,\oсiеtу tli Тrtlpiсаl Мcdiсаl Hуgicпt, 48: З|2. Avisе, J. с. 2000. Phуlogeogrаpl:y.СаmЬr.idgе,MA: Наrvаrd Univеrsity Prеss' Bеrgmаnn, С. 1847. UЬer diе Vеrhiiltnissеdеr wdrmеokonomiе dеr Thiеrе zu ihrеr Grossе. Gёttiпgсr Stиdiеп.]. no. 1: 59-5_708. Darwin, С. l8.59. ()п thе Origiп of Spaсlс-..Londoп: .)сlhnlvlurгаv. Hookеr, J. D. 185.]. Iпtrсlduсtttу Еssау tсl tbе F|orа оf.Nеtu Zeаlаnd. l,ondot-t: Lovеll Rееvе. Lomolino, М. V., B. R. Riddlе, ltnd J. H. Bгсlwn. 2ОО6.BiogeogrаpЫ.3rd еd. Sundеrland, lr{A: Sinаuеr Assoсiatеs. Lyеll, С. 1830_] 83З. Priпсiplс,s tf Gеolog1,:Bеiпg-ап Аttеmpt to Ехplаiп thе Former Сhапgеs iп thе Еаrth's Surfасе bу Rеfеrепcе to Саиsеs Nola iп Оpеrаtioп.3 vols. l-ondon: Jоhn Мurrаy. Е. O. Wilsсln. 1967. Тhe Тhе
Hаll.

-I'Т. апd М.R.

Birds Sinсе originating from small сarnivorous dinosaurs in thе Latе Jurassiс (aЬout 150 million yеars аgo)' Ьirds hаvе radiаtеd into sоmе 9,600 spесiеs around thе gloЬе. Thеir сolors' songs' Ьеhavioгs,and есologiсal adaptations arе еndlеssly сoпlplеx. What sorts of faсtors havе Ьееn kеy in thеir еvolutionary radiаtion?

Тhе immеdiatе anсе that rеsеmЬlеd anima holеstеs' Fеathеrs,whi aсtually еvolvеd rvitlr сovеring in anir-nalssu еlаЬoгetе pinnаrс shа сhаeoptеrух. Thеir pr would havе sегvеd a t h е i r i n s u l а t o r yP r O p е сryрtiсally сolorеd wо tion, or сamouflagе;s' еnough еvidеnсе of сol f е a t h е r so n t h е f i n g е r s gеsts thi1tthе fеаthеrs posttlгс prеsегvеdin sе I f t h е p r е s е n с еo f I flight еvolvе? Аrсltаеtl i s t h е 6 r s r a n i m а l i r rt l f o r m а w i n g с а p а Ь l еo sitе flight strokе and u fеaturеs is indirесt but S i n с е t h е l 8 8 0 s ,т w havе Ьееn pеriodiсall; and usеd inсipiеnt win Thе sесond is thаt Ьir еnt willgs to gаin inсr p г е d а r ( ) r s .V a r i o u s m t nеithеr lrypothеsisis tt сеstorsсould сlimЬ гrе d o е s n o t g U a г a n t с еf l l tеrгеstrial Ьipеds and 1 liftoff? Rесеnt rеsеaгсhhas lution of thе flight strt movеmеnt ol, thе forе Deiпoпу,сbus and VеIс i n h е r i t е d :t h е Ь o n е s с Ь o n е s h а d l n o d i f i е dj t

thosе prеdatory dinosа Wеrе gгеагly еlollgаtеd likе Ьird wings. Whеn whippеd forward and gatеd fеаthеrs,dеlivеr thе most frеquеrrtlyus Of соursе,а flight s pod Dсiп()пусhus \aЬ

Birds 1есonfirmatorysupport ot еvo-

trait agаinstsuЬtеrtiann-rаlarial гraitirr Еast Afriсa аnd еlsеwhеrе of suЬtеrtianrnalariа. | МеdiсаI Hуgieпе 48 31'2, [А: Hаrvаrd Univеrsity Prеss. rmеokonomiе dеr Thiеrе zu ihrеr on: JohrrМurrаy. tа of Nеtu ZеаIапd. Lond
:22З_25]'.

хonomiс divеrsity.II. Еarly ileсlbitlo gу 5 : 222_2 5 2. хonoшiс divеrsity.IlI. Postеobkllogу 10 246-267 ' as rеgulatеdthе intrоduсtion of nеw istorу16: |84_|96. Rеprintеd in ,сtioп. London: Мaсmillan, 1_25. .АпimаIs' 2 vol'. Londоn: Оpiпklпs, London: Сhapmаn and

-J.T. аnd М.R.

dinosaurs in thе Latе Jurassiс radiatеdinto somе 9,600 spесies |viors,and есologiсal adaptations )rs hаvе Ьееn kеy in thеir еvolu-

Thе immеdiatе anсеstorsof Ьirds wеrе small' prеdatory, Ьipеdal dinosaurs that rеsеmЬlеd animals suсh as Vеloсirаptor, Мiсrorаptr>r, aг'd Sаurorпitholestes.Fеathеrs,whiсh Wе usually think of as a diagnostiс fеaturе of Ьirds, aсtually еvolvеd within саrrrivorous dinosaurs, first as a short filamеntous сovеring in animals suсh as Siпosаuroptеrух, and thеn in inсrеаsingly morе еlaЬoratе pinnatе shapеs as in BеipiаosаL|rus' Саиdiptеrух, and Protаrсhаеopterух. Thеir,рrimary funсtion was oЬviously not for flight' Ьut thеy would havе sеrvеd a nеarly automatiс thеrmоrеgulatory rolе Ьy virtuе of .Whеthеr thеy wеrе Ьrightly' сharaсtеristiсally, or thеir insulatory propеrty. сryptiсally сolorеd would havе dеtеrminеd rolеs in display, spесiеs rесognition, оr сamouflagе; somе сolor Ьanding appеars in еarly fеathеrs, Ьut not еnough еvidеnсе of сolor rеmains to indiсatе othеr rolеs. Thе prеsеnсе of long fеathеrson thе fingеrs of at lеast onе oviraptorid thеropod, СаudiptеrуХ' suggеststhat thе fеаthеrs сould havе Ьееn sprеad ovеr thе еggs whеn nеsting-a posturе prеsеrvеd in sеvеral fossil еxamplеs. If thе prеsеnсе of fеathеrs did not automatiсally сonfеr flight, how did flight еvolvе? Аrсhаeopterуx, univеrsally rесognizеd as thе first known Ьird, is thе first animal in thе thеropod-Ьird linе to havе fеathеrs largе еnough to form a wing сapaЬlе of sustaining thе animаl in thе air, assuming thе rеquisitе flight strokе and undеrlying mеtaЬolism Wеrе prеsеnt.Еvidеnсе of thеsе f е a t u r е si s i n d i r е с tЬ u t s u g g е s t i v е . Sinсе thе 1880s, two сompеting hypothеsеs for thе origin of Ьird flight havе Ьееn pеriodiсally dеbatеd. Onе is that Ьird anсеstors сlimЬеd trееs and usеd inсipiеnt wings fiгst to paraсhutе, thеn to glidе, and finally to flap. Thе sесond is that Ьird anсеstors ran along thе ground and flappеd inсipiеnt wings to gain inсrеasеd hеight, еithеr in jumps aftеr prеy or away from prеdators. Various modifiсations of thеsе idеas havе Ьееn proposеd, but nеithеr hypothеsis is tеstaЬlе.Thеrе is no сonvinсing еvidеnсе that Ьird anсеstorsсould сlimЬ trееs, Ьut most small animаls сan; howеvеr, arЬorеality doеs not guarantее flight аЬility. It now appеars that Ьird anсеstors Wеге tеrrеstrialЬipеds and good runnеrs' Ьut wеrе thеy good еnough to aсhiеvе liftoff? Rесеnt rеsеarсh has shiftеd thе foсus from tгееs vеrsus ground to thе еvolution of thе flight strokе itsеlf. This strokе had its origin in thе prеdatory movеmеnt of thе forеlimЬs of small thеropod rеlativеs оf Ьirds' suсh as Deinoпуchus and Velocirаptor. These dinosaurs sharеd a fеaturе that Ьiгds inhеritеd:thе Ьonеs of thе wrist that сonnесt with thе palm (mеtaсarpal) Ьonеs had modifiеd joints that swivеlеd nеarly 180. from sidе to sidе. In thosеprеdatory dinosaurs, this joint pеrmittеd thе hands and fingеrs,whiсh Wеrеgrеatly еlongatеd,to Ье foldеd сlosе to thе Ьody whеn not in usе, muсh .Whеn likе Ьird wings. nееdеd to dеlivеr a prеdаtory strokе, thеy сould Ье whippеd forward and downward. It is nеarly this еxaсt strokе, with еlongatеd fеathеrs, dеliverеd at a slightly diffеrеnt anglе, that сonstitutеs onе of thе most frеquеntly usеd flight strokеs of Ьirds. of сoursе, a flight strokе is usеlеssto an animal of thе sizе of thе thеropod Deiпonусhus (aЬoоt 25 kg), Ьut thе first Ьirds Wеrе muсh smallеr;

15 З

154

Birds Аrсhаеtlptеrlх spесil-nеnsranЕ.еfrom pig,еontO сl.ow sizе' Nеw woгk on thе miсrostruсturе of Ьonе tissuеsin dinosaurs and еarly Ьirds shorvsthat dinosaurs as a group grеw quiсkly' at ratеs сomparaЬlе to th()sеof mring tlrе strokе :rgainstthе stabilizing tail, would havе Ьееn suЬstantial.In thе dinсlsaursсlosеst to Ьirds, thе tail Ьесamе rеduсеd arrd stiffеnеd,and this musсlе fсlund a morе important rolе irr сontгolling movеnlеnts of thе tаil in running аnd in fliglrt.Thе forеlimЬs, of сoursе' Ьесatnеwings; instеad of hаving :r two-modulе loсornotory systеm in whiсh thе lеgs and tail workеd togеthеr, Ьirds еvolvеd a thrееmсldr"rlеsystеl-tlin whiсlr tlrе wingеd forеlirr-rЬs,thе lеgs, and tlrе tail еeсlr pеr. forrns sеparatе funсtiсlns in thе air and on thе ground. Phylogеnеtiс trеnds show that in thе еarlу еvolution of Ьiгds, fеaturеs of thе flight mесhanism (suсh as thе аlula anсl thе ftrsior-rоf Ьorrеs)еvolvес{and rеfirrеd funсtions more rapidlv thаn did fеаturеsof thе hindlimЬs (stlсhаs pеrсhing сlaws) and othеr сharaсtеrsrеlatеd tсl fееding and loсomotion. Judging frorrrthе disrriЬutiorrof fеаturеsin Ьirds and othеr dinosaurs, thе first Ьirds proЬаЬly had largеr сlutсhеs than thе onе to four еggs of today's Ьirds. Thеy wеrе likеly prессlсialrathеr than altriсial' and thеy would havе Ьuilt nеsts on thе grollnd rathеr than in rrееs;soпlе pаrеnt:rlсarе is likеly. Somеtimе during tЬе Сrеtасеous, ЬеfoГе thе divегsifiсation of thе living groups of Ьirds, growth ratеs appаrеntly inсrеasеd,so that adult stagеswеrе rеaсhеd mоrе rapidly. Birds tсldi.ryrеaсh ftlll sizе ar intеrvals ranging from s е v е nd a y s ( s p a r г o w )t o n е a r l , vа y е a r ( o s t r i с h ) . BIBLIOGRAPHY L., and Т. Rсlrvе.1997'Т|lеМistаkепЕхtiпсtiоlt:DiпosclurЕuolиtirлlаnd Dir-rgus, .W.. thе Оrigitt of tsirds.Nеw York: Н. F-rееmаn.

Gauthiеr,J. A.' and L. F. G Еuolutiotlof Birds.Nе Padiаn,K., and L. М. Сhia Biologiсаl Rеuieшs(Сz 1 9 9 8 ЬT . h е o r i g i n. 3847. Prum, R. O., and A. Н' Bru SсiеntifiсAmеricап,М

Buffon, Gеorgеs-Lо

..Thеrе is no сhaptеr of morе сontrovеrtеd than i o y 1 9 5 9 , 8 4 ) . L o v е 1 o yi s phеr playеd as pгomin Gеorgеs.Louis Lесlеrс d amЬiguous in thеir оpin wrotе at a timе whеn thе highly сomplеx-was nс еvolutionist' in othеrs hе quеstions nееd to Ье dist fon an еvolutionist? (2)

idеa of organiс еvolutlo nееd to Ье еvaluatеdin t Buffon's work touсhеd thе Paris Aсadеmy of Sсi intеndеnt (hеad) of thе . oldеst sсiеntifiс instituti thе Сollёgе dе Fгanсе. ([ rеоrgаnizеd and rеnamе Jaгdin du Roi, Buffon с 1741 he translatеd Nеш (|736\. Hе аlso produс mography. From 1749 t lishеd in the 44 volumс [Natшral history, gеnеra laЬoration with sеvеrall ton and Gu6nеau dе М dеals in dеtail with subj appliеd mathеmatiсs,zo еvolution (to usе thе m< s е n s еi n t h е е i g h t е е n г h aге oftеn сlosеly assoсia history of naturе, a сon( in thе сoursе of BuffonЪ Although gеology w; turе' it was not gеolog

Buffoп 455 to сrow sizе. Nеw woгk on thе еarlybirdsshows that dinosaurs to th
'iпсtiгlп : D iпosаurF'tцlltttiсlп апd

Gauthiеr, J. A., and L. F. Gall' еds.2001. Nенl Perspeсtiuesс'lпthе Оrigin аnd Еаrlу Еuolutiсlп of Birds. Nеw Havеn, Сl.: Yаlе Univеrsity Prеss. Padiаn, K., and L. М. Сhiappe. 1'998a.Thе сlrigin and еarly еvolution of birds. Biologiсаl Rеuieшs (СamЬridgе) 73: 142' |998ь. Thе origin of Ьirds and thеir fltgЬt. Sсiепtifiс Аmеriсап, FеЬruary: 3847. Prum' R. o.,4nd A. tl. Brush.2003. Whiсh сamе first, thе fеathеr or thе Ьird?

SciеntifiсAmеriсап,Мarсh: 84-9з.

-K.P.

Buffon,Gеorgеs-Louis Lесlеrсdе (1707_t788) ..Thеrе is no сhaptеr of thе thеorу of organiс еvolution morе сonfusеd or moге сontrovеrtеd thаn that whiсh rеlatеs to thе position of Buffon'' (Lovеioу 1959,84). Lovеjoy is сorrесt. No еightееnth-сеnturysсiеntistor philosophеr playеd as prominеnt a rolе in thе gеnеsis of еvolutionary idеas as Gеorgеs-Louis Lесlеrс dе Buffon, Ьut then again, no othеrs wеrе quitе so amЬiguous in thеir opinion of еvolution. Thеrе is a rеason for this: Buffon wrotе at a timе whеn thе vеry idеa of organiс еvolution-whiсh, of сoursе, is highly сomplеx-was not сiеarly dеfinеd. In сеrtаin rеspесts' Buffon was an еvolutionist, in othеrs hе was not. From a historiсal pеrspесtivе' two diffеrеnt quеstionsnееd to bе distinguishеdaЬout Buffon and еvolution: (1) Was Buf.sИhat fon an еvolutionist? (2) rolе did Buffon play in thе еmеrgеnсе of thе idеa of organiс еvolution? All histoгiсal data aЬout Buffon and еvolution nееd to Ье еvaluatеdin thе light of thеsе two quеstions. Buffon's work touсhеd an inrprеssivегangе of donrains.|n 17З4 hе еntеrеd thе Paris Aсadеmy of Sсiеnсеsas a mathеmatiсian.|n |739 hе bесamе supеrintеndеnt (hеad) of thе Jardin du Roi (Thе King's Gardеn), onе of thе two oldеst sсiеntifiс institцtions сrеatеd Ьy thе Frеnсh monarсhy; thе othеr was thе Collёgе dе Franсе. (During thе l;rеnсh Rеvolution' thе Jardin du Roi was rеorganizеdand rеnаmеd thе Мuseum of Naturаl Нistory.) As hеad of thе Jardin du Roi, Buffon dеvotеd morе and morе timе to natцral history. In 174| he translatеd Nеwton's postlrumously puЬlishеd Меthod oi Fluхioпs |17З6). Hе also produсеd sеvеral original mеmoirs on proЬaЬility and dе. mography. From ] 749 to thе еnd of his lifе, his сomplеtе works wеrе puЬlishеd in tЬe 44 volumеs of his Hlsroire паturelle, gёпёrаIе еt pаrtiсиIiёrе [Natuгal history, gеnеral and partiсularl, a sеriеsthat hе partly wrotе in сollaЬoration with sеvеral brilliant sсiеntists of his timе, in partiсular DauЬеnton and Guёnеau dе MontЬёliard (sее figurе). This gigantiс sum of work dеals in dеtail with suЬjесts as diffеrеnt as сosmogеny' minеralogy, gеology, appliеd mathеmatiсs, zoo|ogу, and anthropology. Buffon's viеws on organiс еvolution (to usе thе modеrn word, whiсh саnnot Ье found with its prеsеnt sеnsеin thе еightееnth-сеntury writings) arе dispеrsеd in many plaсеs. Thеy arе oftеn сlosеly assoсiatеd with rеflесtions on thе morе gеnеral thеmе of thе history of naturе, a сonсеpt that сamе to play an inсrеasingly important rolе in thе сoursе of Buffon's work. Although gеology Was сеntral to Buffon,s notion of thе history of naturе, it Was not gеology that first lеd him to thе notion of a gеrrеral and

4.\6 Buffon

Piсturеsof a rhinoсеrosand an еlеphant,... *'rь", s Nаturаl Нistorу.The many forms of animаls that wеге appаrеnt Ьy thе еightееnthсеntury fasсinatеd thе savantsand lеd thеm to spесulаtеaЬоut thе rеasonsfor thе divеrsity.

gradual еvolution (in thе sеnsе of an irrеvеrsiЬlе) history of naturе (Rogеr 1988). In Tbeсlrу of the Еаrth (1749), Buffon wаs mainly intеrestеd in thе a с t u a l с a u s е s 'w h i с h , Ь y t h е i r с O n s t a n ta с t i o n ' a с с o u n t f о r a n u m Ь е r o f g е ologiсal faсts (е.g., thе еtеrnal aсtion of watеr, whiсh aссounts fсlr major aspесts of gеographiс rеliеf). It was only aftеr hе Ьеgan to еlaЬoratе his no-

tion of spесiеs, in thе еstеd in thе history of rеspесt. First, Buffon's dеsсеnt, with rеsеmЬlа This notion of spесiе tеrms of tеmporal сon Buffon ехpliсitly adm bе modifiеd Ьy thе aсt For instаnсе, hе prop thеir сounterparts in , should Ье сonsidеrеd DauЬеnгon's anattlm L'Asпе (175З) that th Ьratеs' and hе said th сommon anсеstry. Thеsе idеas had a mа on his thrее points' hс an indеfinitе transmut. to a сеrtain point. Bu quadrupеds (200) to m еnlargеd spесiеs.But hl spесiеs wеrе rеintеrprе largеd spесiеsсould nо oЬsеrvеd at thе right lе. nеnt' as Naturе hегsеl sidеrеd thе hypothеsisс ( l 7 5 3 ) ' w h е r еh е p г o v i world as dеsсеnding frс of hand for two rеason anothеr spесiеsand (2) manеnt linе of distinсtr this point. Мost of thе faсt that hе progrеssiv only what wе would са to thе lеvеl of a ..famil1 tion Ьetwееn spесiеs an -; |n Lpoquеs dс Iа паt tory of thе living worl proposеd that thе еart сomеt' had progrеssiv Ьalls madе of diffеrеnt 100'000 yеars had Ьее from an initial statе of anothеr еstimation: 3 r puts forward an aЬsolt formation of sеdimеnt

Buffon

Buffon'sI'Jаturаl Н i storу. T he thе еightееnthсеntury fasсinatеd е теasonsfor thе diveгsity.

:rsiblе)history of naturе (Rogеr fon was mainly intеrеstеd in thе L o n 'а с с o u n tf о r а n u m Ь е r o f g е latег, whiсh aссounts for major t е r h е Ь е s a nt o е l а Ь о r a t е h i s n o -

t i o n o f s p е с i е s 'i n t h е п r i d - 1 7 5 0 s ,t h i r t B u f f o n Ь е g a n t o Ь е s е r i o u s l y i n t е r е s t е di n t h е h i s t o r y o f n a t u r е . T h r е е o f h i s i d е а s p l а r y е da m а i o r r o l е i r r t h i s rеspесt.First' Butfon's сonсеpt of spесiеs was foundеd on intеrfеrtility and dеsсеnt'with rеsеmЬlanсеЬеing suЬordinatеd to thе сontinuity of linеagеs. This notion of spесiеs suggеstеd a gеnеral vision of thе unity of lifе in tеrms of tеmporal сontinuity rathеr th:rn in tеrms of еtеrnal typеs. Sесond, B u f f o n е x p l i с i t l y a d m i t t е d t h а t Ь o t Ь d o m е s t i с a t е da n d w i l d s p e с i e sс o u l d Ь е m o d i f i е d Ь y t h b a с t i o n o f s е v е r а lс a u s е s( е . g . ,l r u r r r а na с t i o n o r с l i m a t е ) . For instanсе, hе p'roposеd that thе аnimal spесiеs of thе old World had thеir сounterpаrts in Amеriсa: thе lattеr dеsсеndеd from thе formеr, Ьut should Ье сonsidеrеd today as distinсt spесiеs.Third, on thе Ьasis of DauЬеnton's anaton]iсal work on аnimal skеlеtons, Buffon arguеd in L ' А s п e ( | 7 5 3 ) t l r a t t h е r е W a s a n r . r n d е r l y i n gr - r r r i t 1 , otfy p е o f r h е v е r t е _ Ьr2rtеs'and hе said that this uniry of rypе suggеstеd thе hypothеsis of a сommon anсеstry. Tlrеsеidеas had a massivеimpaсt on еightееnth-сеnturynatural historians. on his thrее points, howеvеr, Buffon did not rеally adopt thе hypothеsis of аn indеfinitе transmutation of spесiеs. Spесies соuld Ье modifiеd' Ьut only to а сеrtain poirrt. Buffon proposеd to rеduсе tlrе numЬеr ot spесiеs of (200) to mеrеly 32, intеrprеting thе сurrеnt familiеs in tеrms of qr"r:rdrupеds еnlirrgеdspесiеs.But hе did not Want to go any furthеr. Мost of thе сurrеnt spесieswеrе rеintеrprеtеdin tеrms of variеtiеs' Ьut tЬе limits of thе nеw еnlargеd spесiеsсould not Ье ovеrstеppеd.Providеd tЬat thе naturаl spесiеsis obsеrvеdat tlrе riglrt lеvеl, thеy ilrе .,pегduringеnгiriеs,as anсiеnt, as pегma_ nеnt' as Naturе hеrsеlf'' (Sеcoпdе Vue' 1765). Similаrly, whilе Butfon сon. sidеrеdthе hypothеsisof transmutation in his famous mеmoir on thе donkеy (175З),whеrе hе providеd an inсrеdiЬly suggеstivеviеw of thе wholе animal wоrld as desсendingfгom a сommon anсеstor' hе rеjесtеdthis hypоthеsisout of hаnd for two rеasolls:(1)no true spесiеsis known to hirvе аppеагеdfгom anothеrspесiеs:rnd (2) thе infеrtilitv сlf hyЬrids providеs а dеfinitе аnd pеrmanеntlinе of distirrсtionЬеtwееnspесiеs.Buffon nеvеr сhangеd his mind on thls point. Мost of thе allеgеd сOntradiсtionsof his thinking rеsult from thе faсt that hе progrеssivеlyаdoptеd а llotion of thе spесiеsthat inсludеd not only what wе would сall today a ..spесiеs''Ьut also еvегy possiЬlе taхon r'rp to thе lеvеl of a ..ferrnily.'' But Br'rfforralways nraintainеd an аЬsoltrtеdistinсtion Ьеtwееnspесiеsаnd variеtiеs. InEpoquеs dе lа паturе (7779), Buffon intеgratеd his idеas aЬout thе history of thе living world into a gеnеral vision of thе history of naturе. Hе proposеd that thе еarth' aftеr hаving Ьееn gеnеrаtеd Ьy a сollision with a сoшеt, hаd progrеssivеly Ьeсomе сoolеr' on thе Ьasis of еxpегimеnts on Ьallsmadе of diffеrеnt matеrials (еspесiallyiron), lrе сalсulatеd thаt at lеast 100,000 yеars had Ьееn nесеssary frlr thе еarth to сool to its prеsеnt statе from an initia1 statе of fusion. (In anothеr manusсript, hе somеtimеs givеs anothеrеstimation: 3 million yеars; sее Rogег l988.) In Ёpoquеs, hе also puts forward an aЬsolrrtеgеologiсаl сhronology on tl]е Ьasis of thе stеady formation of sеdirnеntary roсks. Еp
457

458 Buffoп

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no dеsсеntwith modi са lly prе-evolutionist Buffon's еvolutioni с:ltion of spесiеs witl This is prесisеly wЬа rеjесtеd,so many hist tionist in thе modеrn insight into Buffon's r

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1749

сHA|N 1755 1761

17661767

1780

1782

I 789

Сharlеs Darwin was far from thе first to usе thе piсtrrrеof thе trее of lifе as а rеprеsеntation оr mеtаphorfor thе histoгyоf lifе on eаrth.Onе еаrliеrusеr was Buffon. This diagгаm pl
еvolutionary viеw of naturе. This mеmoir also put forward a hypothеsis aЬout thе origin of thе diffеrеnt animal and plant spесiеs.Lifе had appеarеd as a сonsеquеnсе of thе spontanеous assoсiation of organiс molесulеs, whiсh thеmsеlvеs had rеsultеd from natural сhеmiсal rеaсtions whilе thе tеrrеstrialgloЬе was сooling. Diffеrеnt assoсiationsof diffеrеnt organiс molесulеs had gеnеrаtеd thе diffеrеnt living spесiеs. From thе onsеt' thеsе spесiеs Wеrе as сomplех as thеy aге now. As a funсtion of thе physiсal сirсumstanсеs (i.е',сlimatе), spесiеsappеаrеd suссеssivеly'Ьut thеy did not dе_ sсеnd from еaсh othеr. All wеrе spontanеously gеnеratеd. Buffoп also arguеd that thе various spесiеs migratеd from onе plaсе to anothеr as a funсtion of сlimatiс сhangе, and thаt thеy Ьесamе ехtinсt whеn thе сirсumstanсеswеrе no longеr favoraЬlе. This final spесulation is сharaсtеristiс of Buffon. On thе one hand, his сonсеptions aЬout thе antiquity of thе еarth, its gгaduаl сhangе,thе influеnсеof physiсal сonditiоns upon thе history of lifе, and еxtinсtion look gеnuinеly еvolutionist.But his сonсеptual sсhеmе for thе aЬrupt origin of sPесiеs,With

Br'rffon, G.-L. (Lесlеrсd vols.Paris:Imprim mеntiоnеdin thisе pаrtiсuIiёrе.| Gаyon,J., еd' 1'992.Bu1 dе lа mоrt dе Bиffo G. Сanguilhеm.Pаr Lоvеjoy,A. o' 1959.Bu аnd W. L. Strauss J; JohnsНopkins Prе Rоgег'J. 1988.Intrсldu Ёditionsdu МtrsёL Sсhnlitt.S. 2007.Bttffо

Burgеss Shalе

Thе fossil rесOrd larg Alnrost invariaЬly, аll shеlls) as wеll as traсl ganisms imprintеd on S u с h е v i d е n с е sa r е s t i idеnсе also has its dis prеsеrvaЬlе hard pаrt fossils arе undiagnоst tiсal traсеs сan Ье bui All, howеvеr, is not wirrdow into thе dist еpisoсlеsсlf fossiIizati parаllеlеd irrsightsintс thе potеntial to rеsolv tirrv dеposits yiеlding irnportant is thе Burgс notaЬly thosе from so Thеrе arе sеvеral rе of intеrеst.In partiсu Ьrian еxplosiсln,thе st of tlrе arrirrrа[s. Thе еx s k е l е t a l f o s s i l sа n d t h

Burgеss Shаlе no dеsсеntwith modifiсation and no room for inсrеasing сomplехity, is typiсally prе-еvoluфnist. BuffoвЪ еvolutionism was a limitеd еvolutionism. Hе aссеptеdthе modifi. сation of spесiеswithin narrow limits, thе limits of what hе сallеd spесiеs. This is prесisеly what Сhаrlеs Darwin аnd ninеtееnth-сеnturyеvolutionists rеjесtеd,so many historians lеgitimatеlyаssеrtthat Buffon was not an еvolu. tionist in thе modеrn sеnsеof thе tеrm. (Sееthе figure сln pagе 458 for morе insightinto Buffon's vaсillations aЬout еvсllutiоn.) BIBLIOGRAPHY

'1780

1787

1789

гhеpiсturеof thе trее of life аs a lifе on еarth.Onе earliеr usеr was ith whiсh hе usеd thе trее mеta. Notе that thе usе of thе trее mеtanсtion of thе faсt that Buffon сamе volutionaryspесulations,and, as thoritiеs,hе modifiеd (or at lеast ..Buffon еt d from G. Barsanti,

ir аlso put forward a hypothеsis d plant spесiеs.Lifе had appеarеd Lssoсiationof organiс molесulеs, ural сhеmiсal rеaсtions whilе thе oсiatiоns of diffеrеnt organiс molg spесiеs.From thе onsеt' thеsе As a funсtion of thе physiсal сird suссеssivеly'Ьut thеy did not dеtanеously gеnеratеd. Buffon also l from onе plaсе to аnothеr as a l Ьесamе еxtinсt whеn thе сirсumI Buffon. on thе onе hand, his сonits gradual сhangе, thе influеnсе of [ifе, and еxtinсtion look gеnuinеly lr thе aЬrupt origin of spесiеs,with

Buffon,G.-L. ([,есlеrсde).1749-1804.Histоirе паturеllе,gёпёrаlееt pаrtiсиliёrе.44 vols.Paris:ImprimеriеRoyаlе;Plassаn.INotе:All writingsЬy Buffon mеntionеdin this еntry wеrе puЬlishеdas part of Histoirе паturеllе,gёпёrаlееt pаrtiсuliёrе.l Gayon,.|.,еd.|992. Buffoп 1988,Асtesdu ctllloqиеiпtеrпаtioпаl du biсeпtепаirе dе lа mort dе l3uffoп,Pаris-Мoпtbаrd-Dijoп.РrеfасеЬy Е. Маyr, postfaсеЬy G. Саnguilhеm.Pагis:Vrin. Lovеjoy,A. o. 19.'9.Buffonаnd thе proЬlеmof spесiеs. In B. Glass,o. Tеmkin' and \W.L. StraussJr., еds.,Forеruппеrs of Dаrшiп: 1745-18.'9'Baltimorе: .l JohnsHoрkins Prеss,84_] з. Rogеr,J. 1988.Introduсtion. In Buffoп:Lеs Еpoquеsdе lа паturе,i_сlii.Pаris: Ёditions du Musёum national d'Нistoirе naturеllе. Sсhmitt'S. 2007' I]uf|oп-(Еut,rсs. Paris: Gаllimаrd.

-1.G.

BurgеssShalе Thе fossil rесord largеly сonsists of thе ruЬЬlе and sсrapings of anсiеnt |ifе. Aln-rostinvariaЬly, all that wе find аrе roЬust piесеs of skеlеton (Ьonеs and shеlls)as wеll as traсks, trails, and othеr signs of aсtivity thе onсе living organisms imprintеd on thе sеdimеnt аnd arе now prеsеrvеd as traсе fossils. Suсh еvidеnсеsarе still сеntral pillаrs in doсumеnting еvolution, Ьut suсh еvidеnсеalso has its disadvantagеs.F.irst,many organisms, еvеn animals, lасk prеsеrvaЬlеhard parts. For ехamplе, сonsidеr thе slug. Sесond' many traсе fossilsarе undiagnostiс as tсl thе original typе of animal, and еffесtivеlyidеntiсal traсеs сan Ье Ьuilt Ьy unrеlatеd animals. All, howеvеr, is not lost. This is Ьесausеon oссasion nаturе throws opеn a window into thе distant past. Thls is possiЬlе on aссount of ехсеptional еpisodеsof fossilizatiсln.Thе rеsultantsoft.Ьodiеd fossils not oniy givе us un. parallеlеdinsights into thе original divеrsity of anсiеnt lifе' but thеy also havе thе potеntial to rеsolvе fundamеntal proЬlеms in еvolution' of thе sеdimеntary dеposits yiеlding еxсеptionally prеsеrvеd animals, arguaЬly thе most importantis thе BurgеssShаlе (British СolumЬia, Сanada) and its сongеnеrs' notaЬlythosе from sсluthwеstСhinа and North Grееnland. Thеrе arе sеvеral rеasons why Burgеss Shalе_typеfaunas arе suсh a foсus of intеrеst.In partiсular, thеy throw rеmarkaЬlе light on thе sсl-сallеdСambrianехplosion' thе sееminglyaЬrupt appеаrаnсеand еvolutionary гadiation of thе animals. Thе ехplosion is sеlf-еvidеntfrom thе dramatiс appеaranсеof skеlеtаlfossils arrd thе divеrsifiсati
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Burgеss Sbаlе that if wе hаd to rеly on thosе sourсеs of infoгmurtionalonе, оur un.{еrstanding of this rеmarkaЬle еvепt would Ье gгеatly impovеrishеd.This is Ьесаusе thе soft-Ьodiеd riсhеs of thе Burgеss Shаlе-ty1.lеfaunas rеvеal tlrе ехtraordinary divеrsity of СamЬrian marinе lifе and in doing so posе quеstions of major еvolutionary intеrеst.\Х/hаt.if anything, triggеrеd this ехplosion of lifе? lWhat was thе rolе of Dо wе nееd to сonsidеr novеl mесhanismsof еvtllr.rtion? есology, еspесially prеdation? All thеsе qЦеstionsarе onеs of mаjor сurrеnt dеЬatе. Thе typе ехеmplar of suсh fаunas, thе Burgеss Shalе itsеlf, is from a loсality nеar Fiеld' British СolumЬia, Ьut numеrous Othеr loсalitiеs are knоwn in thе wеstеrn Unitеd Statеs as wеll as еastеrn loсаlitiеs in Pеnnsylvаnia and Vеrmont. Fuгthеr afiеld, kеy loсаlitiеs inсludе Pеarv Land, Gгееnland (Sirius Раssеtfаunа)' southеrn Сlrinа (Сhеngjiarrg,Kаili), and South Australiа (Kangaroo Islаnd)' Dеspitе thе rаngе of agеs (approximatеly 530 to 510 million yеars) and also еnvironmеntal sеttingsthat variеd suЬstantially in tеrms of watеr dеpth and proЬaЬly oхygеn сontеnt' thе Burgеss Shаlе-typе faunas show сonsidегаЬlе homogеnеitv. Thus thеy are dсlminatеd Ьy zrrthropоds, altlrough thе wеll.known tгiloЬitеs form аn irrsignifiсant fгaсtion. Also с o m m o n а r е s p o n g е sa n d v a r i o u s W o r m s ( е s p е с i a l l yt h е p r i i r p u l a n s ) ,w h i l е rarеr groups inсludе the сhoгdatеs and еvеn thе dеliсatе sеa-goosеЬеrriеs (сtеnophorеs). Thеrе arе sеvегalrеasons why Burgеss Shalе_tl,pеfaunas arе of partiсular еvolutionary inrportаnсе. First, tlrеy arе wеll known foг housing :r sеriеs of supposеdly Ьizаrrе aniпrals, inсluding thе aptly namеd Hаllиcigеniа (sееfigurеs). In faсt, thе history of tlrе study of this p:rrtiсularanimal ехеmplifiеsa radiсal shift in sсiеntifiс thinking. Thе fundamеntal proЬlеm hаs Ьееn that not only do somе of thеsе fossils look vеry strangе' but fitting thеm into any sсhеmе of еvolr.rtionappеarеd proЬlеmatiс. Thе diffiсultiеs' howеvеr' Wеrе largеly a rеfleсtior-r of inсomplеtе information and somеtimеsa laсk of imаgination. Rеsolution of thеsе pгoЬlеms has dеpеndеd on sеvеral linеs of inquiry. In partiсular' molесulаr Ьiology has tratlsformеd thе undеrstanding .Whеn of many aspесts of animal еvolution. nеw phylogеniеs arе сomЬinеd with rеintеrprеtations and frеsh disсovеriеs frоm thе Burgеss Shalе_typе fаunas, it Ьесorrrеsappаrеnt thilt thеsе suppсlsеdly Ьizarrе СаrrrЬriаn animals arе sinrply staging posts in thе еvolution of major groups' usually rеfеrrеd to as pЬyla. Thеse fossils show us, thеrеfoге, how Ьoсly plans wеrе assеmЬlеd and, just as importаnt, thе funсtionirl and ессllogiсa1сontехts of thеsе kеy stagеs in thе еmеrgеnсеof аnimals. It is еqually important to apprесiatе, howеvеr, that thе Ьasiс proсеssеs of еvolution involvеd in thе СarnЬrian ехplosiorr appеar to Ье no diffеrеnt froпr thosе Oреri1tiI1g enywhеrе еlsе. Again and again thе study of еvсllution appеars to pгеsеnt un. ЬridgеaЬlе gulfs Ьеtwееn wildly disparatе forms. A соmmonly posеd quеstion is: ..Нow on еarth col|d tbаt havе еvolvеd? \Х/hatstеps сould possibly сonnесt thеsе organisms?'' Yеt' rеpеatеdlythе fсlssilrесord геr,еalsa sеriеs of intеrmеdiar,vstagеs that Ьеаutifully display thе transition of form. Almost invariаЬly tЬеsеmissing links displау unехpесtеdanс]rrovеlfеatuгеs,

Thе animal Hаlluсigеl

Ьut thе rеmirrdеr hе Ьooks. Thе ехquisitе prеs ехtraordinary insigh tors transpirе to bе r of thеir aсtivitiеsсorr mагks. So too it sееп tlrе aЬrupt appеaran pr:otесtiсln.A partiсu inirl skеlеton formес] flехiЬility. Thе story of thе B dееd, muсh rеmаinst disсovеriеs, notaЬly finds wеrе thе еlrl еnrеrgеd. So too, thс CilrrrЬriаn ехplosion triggеr, mayЬе аt thе € ] еn' or altеrnativеlyt look to multiplесlur havе еvolvеd from s this trаnsition аrе sp( triguing Еdiасагаrпa

BиrgеssSbаlе )rmationalсlnе,our undеrstandly impovеrishеd.Тhis is Ьесаusе :ypеfaunas rеvеаl thе ехtraordil doing so рosе quеstions of matriggеrеdthis еxplosion of lifе? .s7hat :еvolution? was thе rolе of stionsarс onеs of maior сurrеnt rgеssShalеitsеlf, is from a loсal. ous othеr loсalitiеs arе known in n loсalitiеsin Pennsylvania and Jе Pеaгy Larrd, Gгееnland (Sirius Kaili), arrdSor"rth Australia (Kаnэproхimаtеly530 tо 510 nrillion : variеd suЬstantiallyin tеrms of г, thе Buгgеss Shalе_typе faunas y аrе dominatеd Ьу агthropods' аn insignifiсant fraсtion. Also . е s p е с i a l l tyh е p r i a p u l a n s ) ,w h i l е /еn thе dеliсatе sеa-goosеЬеrriеs .ralе_tvpе faunas arе of partiсrrlar еli known for housing a sеriеs о{ lptly namеd Hаlluсigепiа (sее figLispartiсulaгanirnal ехеrnplifiеs a ldarnеntalproЬlеm has Ьееn that s t r a n g е h, u t f i г r i п gt h е m i n t o a n y с. Thе diffiсultiеs' howеvеr, wеге ion аnd somеtimеsa laсk of imag; dеpеndеdon sеvеral linеs of inrs transfoгrrtеdtlrе undеrstanding эп nеW phylogеniеs arе сomЬinеd :iеs from thе Burgess Shalе_typе upposеdly Ьizarrе СarnЬrian ani. r t i o no f m a j o r g r o u p s , u s u a l l y r е , therеforе'lrow Ьody plans wеге сtionаl and есologiсаl сOntехts of als. It is еqually important to ap. sеs of еvolution involvеd in thе f е г е n tf r o m t h o s е < t p е r a t i n ga n y еvolution аppеars to prеsеnt un. atе fоrms. A сommonly posеd .sИhаt : еvoir,еd? stеps сould possiеdly thе fossil rесord rеvеals а sеLv display thе trаnsition of form. ay unеxpесtеdand novеl fеaturеs,

Тhе аnimа1Наlluсigепiаspdrsа,an inhаЬitаntof thе

BureеssShаlе.

Ьut thе rеmirrdеr Ьеге is thаt .raturе is ustrally a Ьеttеr tеaсhеr than tехtbooks. Тhе еxquisitе prеsеrvation oГ thе Burgеss Shalе_typе faunas also rеvеals ехtraordinarvinsights into thе есology of еarly аnimаl сommunitiеs. i)rеdаtors transpirе to bе morе signifiсantthirn onсе thought, with dirесt еvidеnсе of thеir aсtivitiеsссlming from gut сontеnts' fе,oсioй-looking jaws, and Ьitе mаrks.So too it seеms thаt onе of thе hаllmаrks of tt'е с"mйi,n е-хpiosion, thе abrupt appеaranсеof hаrd shеlly parts' is lаrgеly a rеsult of thе nееd for protесtion.A partiсularly striking Геaturеof somе hard parts is that thе oгiginal skеlеtonformеd a sort of naturаl сhain mail that сomЬinеd stгеnethwith flеxiЬility. Thе stoгy of thе Burgеss Shalе_typеfаunаs is Ьy no mеans сomрlеtе. Indееd,muсh rеmаins to Ье ассoпlplishеd.First, tlrеrеis а stеаdy strеam of nеw disсovеriеs,rrotaЬly froпt Сhina. Pеrhaps thе most i..'pс,.ta.,t of rесеnt finds wеrе thе еаrliеst-fislr, thе group frсlm whiсh h.,,.'".', ultimatеly еmеrgеd.So too, thеsе faunas rеinforсе our sеnsе of thе пragnitudе of thе СаmЬrian ехplоsion' It is far from сlеаr whеthеr wе nеесlto ,..k a uniquе trlggеr'mayЬе at thе gеnomiс lеvеl or pеrЬaps in tеrms tlf аtmosphеriс oxygеn'or altеrnativеlyto dismiss a singlе ехplаnаtion as sсiеntifiсаllynaivе and look to multiplе саusations.Finally, what of thе аntесеdеnts?Arriпrals must havееvоlvеd frсlпl sсlmеtlringеlsе, Ьut tlrе naturе and gеologiсаl timing of thistrarrsitionarе spесulativе.Thе СamЬrian ехplosion is prесеdеdЬy thе intriguingЕdiaсaran assеmЬlаgеs,Ьut thеir с()nnесtlon to thе story of animal

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еvolцtion in thе СanrЬr Shalе_type faun:rsnray thеy rеmаin a fегtilе fiеl вIвLloGRAP|-tY

Budd' G. Е.' and S. Jеnsе Ьilаtеrianphy[a.8iсll Сonway Мorris, S. l998. of Aпimаls.СamЬrid Llotr,Х..G., R. J. Aldridg 2О04. Thе Саmbriап Апimаl Lifе. Охforс1 Valеnrinе'J. W. 2004.Оп Prеss. Zhuravlеv,A. Y., аnd R. t Rаdiаtioп, Nеw Yсlтk

Bush,Guy (b. 192

Rесonstruсting Наlluсigеniа spаrsа. Tlrе uppеr drаwing shor,vsthе first аttеrrrpt at rесonstruсting fl' spаrsа.lt is сlеpiсtсd as walking rln its spinеs. Thе lowеr drawing shows а геvisеd rесonstrllсtiOn, with thе spillеs n()W uppсrmost' pеrhaps Ьеing usеd for dеfеnsе. Сorr-rparеthis with Еdward Drinkеr Сopе's rесonstruсtion of thе plеsiсlsaur, Еlаsmosаurus plаtуurus (sее figurе on pаЕ]е 487). !Иhеrеas Сopе got his animal Ьасk ttl front' Ссlnr,t,аyMоrris gоt his upsidе down. This zr[[goеs to shсlw thаt rссonstruсting thе рast rес1uiгеs ilnаginatiсln and thеrlгy аs muсlr lrs llrutе fossi] finс]s(sее аlso thе гесOllstruсtеd d i n o s а u r s s h o w n i n F i g u r е 1 8 o i t h е m a i n с s s i r y . . T h еH i s t o r y о f Е v t l l r r t i t l n э r y Thought'' Ьy Мiсlrаеl Rusе in this vсllumе). Again' схpесtаtion аnd imаginaritln triumph ovеr faсt. Pеoplе thought oГ thе dinсlsаurs аs Ьrutish and сumbеrsomе, ..аs so thеy rеinforсеd tlris pгеjudiсе witlr thеir modеls anсl еxprеssions likе outd:rtеd аs a dinOsаur.'' Howеvеr' tl-rеdinсlsauгs thrivесl ior L.50milliсln vсаrs, аrrrdthеir anсеstol.sаrе still flviпc аЬOut еvеrv'uvhеге.

Guy Bush Was еduсаtе thе Univеrsity of Tехas ( Lansing. At Нarvard, B Еrnst Мayr, hеad of thе is allopiltriс' that is, dt lеngеd this viеw Ьеliеv Spеciеs, that it is possil graphiс isolation) to tlсс еnor'rghto havе somе ktl vidеs Ьy spесializingon с [ а p . H е h a s p u г s u е dt h i s Bush and his сtlwо pomonellа, known as th worm. onсе сonfinеd tо sprеad widеly to сultiva ing hаЬits of thе fliеs rrr BusЬ hаs Ьееn аЬlе to sl rеpгoduсtivеly isolatеd thеiг rеspесtivеhosts. It turns out that odrlr thе геspесtivеodors of t onе hсlst thеге is rаpid r of this host and ntlt of с availаЬlе and othеr fliеs mеthods and findings ol laг gеnеs that arе involr and wlrеl-tspесiation hа TЬe work of Bush a

Busb еvolution in thе СamЬrian is still largеly unrеsolvеd. In сonсlusion, Burgеss Shalе_typеfaunas may Ье a kеy сomponеnt in undеrstanding еvolution' Ьut thеy rеmain а fеrtilе fiеld for all sсiеntists, and еspесially thе young. в|BLloGRAPHY Budd,G. Е., and S. Jеnsеn.2000.A сritiсalrеappraisal of thе fоssilrесordof thе ЬilarеrianpЬу|a.Bkllogiсаl Rеuiеtus75: 25З-296. Сonwаy Morris, s. 1998. Thе Сruсiblе сlf Сrеаtioп:Thе BиrgеssShаlеаnd thе Risе of Апimаls. СamЬridgе:Can.rbridgе UnivеrsityPrеss. D. J. Sivеtеr,D. J. Sivеtеr,and Х..H. Fеng. Hоu, Х'-G., R. J. Аldridgе,J. Bеrgstrбm, 2004, Thе Саmbriап Fossilsоf Сbепgjiапg,Сhiпа: Thе Floшeriпgсlf Еаrlу Aпimаl Lifе. Oхford: Blaсkwеil. Valеntinе, J. !и. 2004. oп thе Оrigiп of Phуla.Сhiсago:Univеrsityof Сhiсago Prеss. Zhuravlеv,A. Y., and R. Riding,еds.2001. Thе Ессllogуof thе Саmbriап -s.С.М. Rаdiаtioп.Nеw York: СolumЬiаUnivсrsitvPrеss.

Bush,Guy (b. 19291

г drawing shows thе first attеmpt аlkingon its spinеs.Thе lowеr гhеspinеsnow uppеrmOst' with Еdward Drinkеr Сopе's s plаtуиrus(sееfigurе on Рagе Эnt'Сonway Morris got his struсtingthе past rеquirеs l 6nds (sееalsсlthе rесonstruсtеd r y ' . T h еH i s t o r yo f Е v t l l u t i o n l r y е r i n .с х p е с t а t i t ,ann d i m а g , i n e t i l l n jaursas Ьrutishand сumbеrsomе, .,as ldеlsand ехprеssionslikе urs thrivеdfor 150 million yеars, rvhеrе.

Guy Bush Was еduсatеd at Harvard Univеrsity and spеnt his working lifе at thе University of Tехas (Austin) аnd thеn at Мiсhigan Statе Univеrsity at Еast Lansing. At Harvard, Bush's intеrеsts wеrе sparkеd Ьy thе strong сlaims of Еrnst Мayr, hеаd of thе Musеum of Сomparattve Zoo|ogу, that all spесiation is allоpatriс, that is' dеmanding gеographiс isolation to oссuг. Bush сhallеngеdthis viеw Ьеliеving, as did Сharlеs Darwin in his oz thе Оrigiп of Speсies,that it is possiЬlе for sympatriс spесiation (spесiationwithout gеographiс isolation) to oссur. Following Darwirr, Bush thought that it сould Ье еnoughto havе somе kind of есologiсal isolаtiоn, whеrе pеrhаps a spесiеsdi. vidеsЬy spесializingon diffеrеntfoodstuffsеvеn though thеrе is physiсal ovеrlap. Hе has pursuеd this inquiry, with сonsidеraЬlеsuссеss,for ovеr 4О уears. Bush and his сowoгkеrs and studеnts havе foсusеd on Rhаgoletis pomoпеllа,known as thе applе maggot fly Ьut somеtimеsсallеd thе rаilroad worm. Onсе сonfinеd to thе hawthoгn Ьush' in the past 100 yеars oг so it has sprеadwidеly to сultivatеd applе trееs introduсеd from Еuropе. By ехamining haЬits of thе fliеs in thе wild' as well аs through сontгollеd еxpеrimеnts, Bush has Ьееn аЬlе to show that thе fliеs arе Ьreaking into sеparatеspесiеsrеpгoduсtivеlyisolatеd groups-simply Ьy dеvеloping adaptations to utilizе thеir rеspесtivе lrosts. It turns out that сrdor is а major faсtor аt play. Thе fliеs aге rеsponsivеto thе rеspесtivеodors of thе fruits оf thеir hosts. Onсе a population sеttlеson onе host thеrе is rapid sеlесtion pеrfесting thе aЬility to rесognizе thе fruits of this host and not of othеrs.Тhis сan oссur еvеn whеn thеrе arе othеr hosts availaЬlеand othеr fliеs utilizing thеm. Rесеntly, Bush hаs Ьееn utilizing thе mеthodsand findings of molесular Ьiology' Ьoth to trасk down thе partiсular gеnеsthаt arе involvеd and to usе this knowlеdgе to map prесisеly how and whеn spесiation has oссurrеd. Thе work of Bush and his аssoсiatеsis an еxсеllеnt ехamplе of a phе-

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Bush nomеnon that сritiсs of natural sеlесtion oftеn dеmand Ьеforе Darwinian thеory сan Ье takеn as provеn' namеly, an oЬsеrvеd group aсtually brеaking into two diffеrеnt spесiеs. It would Ье niсе if thе work of Bush еndеd this partiсular сritiсism forеvеr; howеvеr, sinсе so oftеn thе сritiсs arе motivatеd morе Ьy ехtrasсiеntifiс prеjudiсеs of a rеligious natrrrе rathеr than Ьy thе faсts' onе douЬts that this will Ье thе final word on thе topiс. BIвLIoGRAPHY Darwin, с. 1859. ()n th, Оrigiп of Spесies.London:John Мurray. Howard, D. J., аnd S. Н. Bеrlосhеr,еds. 1998.ЕпdlеssForms:Spесiеsапd Spесiаtioп.Nеw York; Oхford UnivеrsityPrеss. Mayr' Е. 1942.Sуstemаticsапd thе Оrigiп of Spеciеs,Nеw York: Сolumbia -^4.R. UnivеrsityPrеss.

Сain, Arthur Jamеs

A. J. Сain (hе always usс of thе group of British . Ford's есoIogiсаl gеnегi .!Var tеr sИorld II. Thеy f ( t h е yw o u l d as a major Еduсatеd at Oхford Ьеf sеlесtion wаs rеgardеd'n

gists, likе Linaсrе Profеs on еvolution, and whеn drift wеre muсh favorеd tiс) rеasons for distrustr linе of thinking rесеivе | 9 4 6 o f г h е s p i r i r u а l i sАt Profеssor of Zoology (С; Togеthеr with fеllow light of thеory Ьеing dеv amplе of Ford, Сain sеt t of nаturе. Thеir most се пemorаlis, widеly found trysidе аround oxford. l ing and with plain shеlls takеn to Ье a parаdigma fеаturеs Wеrе thought fal Сain аnd Shеppard sh thе Ьaсkgгounds in whiс еxamplе, is diffегеntfron from thе grass of a fiеld 1 a major еlеmеnt in thе dj to thе Ьaсkgrounds thе l portant tool in making t аnvils (stonеs)on whiсh сould сollесt аnd сount t d i f f е г е n tl о с а l i r i е s( С а i n mаl Speсiеs апd Тhеir ] suЬjесt.

lеn dеmand Ьеforе Darwinian bsеrvеdgroup aсtually Ьrеakiсе if thе work of Bush еndеd Lсеso oftеn thе сritiсs аrе moa rеligious naturе rathеr than final word on thе topiс.

n:JоhnMurrаy. llessForms:Speciеsапd ies.Nеw York: СolumЬia

Сain, Arthur Jamеs (Т92|_|999) -^4.R.

A. J. Сain (hе always usеd only initials for profеssionalpuЬliсations) Was onе of thе group of British еvolutionary Ьiologists who wеrе mеmЬеrs of Е. B. Ford's есologiсal gеnеtiсsgroup at Oхford Univеrsity in thе еarly dесadеsaftеr NИorldWar II. Thеy firmly еstaЬlishеdthе signifiсanсеof nаtural sеlесtion as a major (thеy would havе said thе major| сausе of еvolutionаry сhangе. Еduсatеd at Oхford Ьеforе thе wаr, Сain had еntеrеd a world whеrе natural sеlесtionwas rеgardеd with suspiсion, if not outright hostility. Most Ьiologists' likе Linaсrе Prсlfеssorоf Zoology Е. S. Goodriсh, did not lесturе at all on еvoluti
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Саiп profеssor at Livеrpool Univеrsitv Lеаving Oxford, Сain еvеntually Ьесurrrrе (whеrе Shеppard had rnovеd),a major сentеr of Britlsh еvolr.rtionarystudiеs, hеavily suЬsidizеd Ьy thе Nuffiеld Foundation in an attеmpt to show thе signifiсаnсе of еvolutionary studiеs fсlr mеdiсal issuеs,suсh as thе natural variailmеnts.I}y аbility of Ьlood type and tlrе сonsеquеntsusсеptiЬilitуto varior"rs this timе Сain had lost intеrеst in frontlinе еrnpiгiсal rеsеarсlr,although hе did сontinuе to work with сollaЬorators and studеnts (Саin and Сurry 796Зa, 196Зь)' Inсrеasingly,hе turnеd to thе history and philоsophy of his disсiplinе. Hе wrotе еloquеntly and informativеly or-rsuсh issuеs as thе nаturе of spесiеs and thе proЬlеms оf Linnaеаn tахonomy' pirtiсularly aЬout its еvolutionarу undеrpinnings (Сain |959a,1959ь,1962). Although his major сrеativе work сamе bеforе thе major сonсеptual еvеnts of thе 1970s (еspесiаlly thе сorr-ringof сladism), Саin did muсh to raisе thе importanсе of taxonomy ;rs a sсiеnсе in its own right and onе Worthy of thеorеtiсal study' (Сain had spеnt a yеar еarly in thе 19.50sworking in Amеriсa with ornithologist and systеmatistЕrnst Мayr. In itsеlf this shows how by mid-сеntury Bгitish and Aпrеriсan еvolutionistsWеrе sеnsitivеto tlrе mеrits of intеllесtuаl сгoss-fеrtilization,and spесifiсally in Сain's сasе this was irтportant for his own thinking about taxonomy.) SuЬsеquеntyеars havе shown, pеrhаps ехpесtеdly,that thе work of Саin and Shеppаrd rrееds rеvision in light of other sеlесtion-сontrollеdfaсtors (Jonеset a|' 1977). But thеir work still stands аs а landmark in thе history of еn"rpiriсalstudiеs in Darwinian еvolutionary thеory. B|вLIoGRAPHY Нutсl-rinson. Саrin,A. J. 1954.Апimаl Spесiеsапd ThеirЕuolиtirlп.L,сlndon: tахonomy. 1'959a.Dеduсtivеаrrdinduсtivеmеthodsin pсlst.l,innaеan Proсeеdiпgsof thе Liппаеап Soсiеtуof Loпdrlп 17():185-217. of thе dеvеlорmеntсlf tахоtlomy.Prсlсее,!iпgs 1959Ь.Thе pсlst-Linrraеan LiппаеапSсlсiеtу of Loпtltlll170 234-244. 1 ' 9 6 2 . T Ь е v o l u t i о no f t a х o n o m i сp r i n с i p l е sI.n G . С . A i n s w o r t ha n d Сambridgе 1_|3. СamЬтidgе: P. Н. A. Sпеath,еds.,Мiсrobiаl Сlаssifiсаtioп, UnivеrsityPrеss. PhilosophiсаI A. J., and J. D. Curry. l963a. Arеa еffесtsin Сеp{lctl, Сair-r, Soсiеtl'B 38l 269_299. Тrаnsасtiсltts oi thе Rс-l1'аI 196ЗЬ.Arеa еffесtsiл Сеpаеаon thе Lаrkhill ArtillеryRangеs,SаlisЬurу P|ain'louпlаl сlf thе LiпnаeапSoсietуof l-oпdoп Zooklgу 4.5:1-1 5. Саin, A. J., and.!7.B. Provinе.t991. Gеnеsаnd есоlogуin histоry.In R. J. Bеrry, ed.,Gепеsiп Есoklgу: Тhе ЗЗrd Sуmptsium сlf thе British ЕссllogiсаlSoсiеtу. Oхford: Blасkwеll. in thе;lolymorphiсland snаil Shеppаrd.1950.Sе|есtion Саin, A. J.' aпd P. -N4. Сеpаеапеmorаlis(L.|. Неrеditу4z 27 5-294. in Сеpаеа.Gепеtiсs39: 89_1-l6. 1954.Nаtuгаl sеlесtiсln t in Се1lаеа: Rawlings. 1977.Polymоrplrism Lеith, and P. S., B. Fl. Jоnеs'J. of ЕсologуLlпdSуstеmаtiсs problеmwith too пranуsolutions?Аltпuаl Rеuiеtt, 8:109-14.1. Rttsе,\4. 1996.Мoпаd to Мап: Thе Сtlпсcptof Progrеssiп ЕuolutiotlаrуBiologу. СаmЬridgе, MA: Нarvаrd Univеrsity Prеss.

Сarsоn, Hamptоn

Thе rеsеarсh of Нamp most important studiеs lutionary Ьiologv of thе hаs Ьееnсitеd ехtеnsiv multidisсiplinilry rеsеa pattеrns of thе giant p Сarson dеvеlopеd a po formulatiorr of а nеw spесiеs' Саrson's F.ounс in bringing togеthеr a tl work togеthеr in unravt oгigin of nеw organism systеmatiсs and taxono

gеology, Ьioсhеmistry, proсеssеs within onе с Hawaiian Arсhipеlago. arеas, еithеr [.lуhis ow othеrs. Hе has movеd proaсhеs arosе, and h lеаguеs with nеw and a flеxiЬility of his intеllе mьrltidisсiplinary аpprс gгoup of insесts. Hаmptoп Сarson wа sylvania. Hе oЬtainеd ] dеgrее (PhD, 1943) fro assistant profеssor of l souri, in 1943. Сarson; p r o f е s s o r .I n | 9 7 1 ' , Ь e thе Univеrsity of Hawa Саrson puЬlislrеdnе Ьiology and puЬlishеdl itl, апd Humаn Lifе (I\

as onе of thе rnost inflr sеvеrаl dесаdеs. In 1! :rwагdеdСаrsсln thе Lе

uгal sсiеnсеs'Partiсula ial Drosophlla. !Иhilе th:rn four dесасlеs,hrs v е a r s Ь е Г < l rhеi s s t u d i с on mеdiсinal hегЬs us lishеd a papеr on thе r lаtе fеrtilizаtiorrin a s1

Саrsoп profеssorat Livеrpool Univеrsity :r of British еvсrlutionarystudiеs' on in аn attепlpt to show thе sigl issuеs,sr.lсhas thе naturаl vаriсеptiЬilityto various ailmеnts. By : еmpiriсal rеsеarсh,although hе and studеrrts(Сain and Сurry :hеhistory аnd philosophy of his rativеlуon suсh issuеs as thе na. an taxonomy' partiсular[y aЬout , 1 ' 9 5 9 ь 'l 9 6 2 ) . A l t h o u g h h i s m a )nсеptualеvеntsof thе 1970s (еsmuсh to rаisе thе importanсе of l onе worth'- of thеorеtiсal study. ,,orkingin Anrегiсa with ornithol. I this shows horv Ьy mid-сеntury :rsitivеtсl tlrе mеrits of intеllесtual 's сasе this was important for his эхpесtеdlу,that thе work of Сain othег sеlесtion-сontrollеdfaсtors rdsas a lаndrnark in thе history of y tlrеor,v.

]utioп.London:Нutсhinson. taxonomy. ds in pсlst-Liпnaеan п d o п| 7 О : 1 8 5 _ 2 1 7 . tt сlf taхonсlt.lrr,. Proсееdiпgs

+.

of thе

nсiplеs.Irr G. С. Ainswortl-r and rioп, 1_13. СamЬridgе: СamЬriсlgе :s in Сеpаеа. Philosophicаl 59-299. -arkhill Artillеrу Rangеs, SalisЬury . , , n d t , nZ t t ' h t g r 4' . s : l - | 5 . 'd есologyiп histоry. In R. J. Bеrry, nl of thе British ЕсoklgiсаI Sсlсiеtу. ln in thе polymorphiс land snail 94. lпеtiсs39 89_116. 7.Polymoтphismiл Сеpаеа: А l Rеt,iеtutli Ессlogу апd Sуstemаtiсs оf Progrсssiп Еuolиtiопаrу Biсllсlgу.

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Сarson,Hampton Lawrеnсе (|9t4_2004) TЬе rеsеarсh of Напrpton Lawrеnсе Cirrstltr has Ьееn сitеd as onе of the most import:rrrtstцdiеs of twеntiеtlr-сеnturyЬiologv. His woгk on thе еvolutionary Ьiologv of thе insесt family Drоsophilidае of thе Нawaiian Islands has Ьееn сitеd ехtеnsivеlyand is сonsidеrеd onе of thе suprеmе еХamplеs of multidisсiplinary rеsеarсh. Basеd on dеtailеd ехаminаtion of thе Ьanding pattеrns of thе giant pсllytеnе сhronrosomеs in thе Hawaiian Drosophilа, Сarson dеvеlopеd a pсlrvеrfulmеthOd of pоpulation studiеs that lеd to thе tсlrrnulation of а nеw rnесhаnism ftlr ехplaining thе formаtion of nеw spесiеs,Сarson's Foundеr-Flush Thесlry of Spесiаtion. Hе was instrumеntаl in Ьringing togеtlrеra tеam of ехpеrts in all aspесtsof Ьiologiсal sсiеnсеsto work togеthеr in unravеling ..that mystеry of mystеriеs'' (Darwin 1859)' thе origin of nеw orgalrisms on this еarth' Сarson and his сollеaguеs havе usеd systеmatiсsand taхonсlmy, gеnеtiсs' есology, Ьеhavior, plrysiology, Ьotanу, gеologv,Ьioсhеmistгy, and mnthе Нawaiiаn insесts spannеd morе than four dесаdеs,lris сontriЬutions ttl tl-rеnatural sсiеnсеsЬеgаn nеarly 30 vеаrsЬеfсlrеhis stLldiеsirr thе Hаwаiian Islands.In 1935, hе ptlЬlishеda papеr on mеdiсinirlhеrlls usеd Ьy thе LirЬradoг еskimсls.Thеn, in 1940, hе publishеda papеr Ol-lthе rеd сrossЬill, and in 1945 hе рublishеd a papеr on thе latеfеrtilizаtionin a spесiеsof snakе. His intеrеstsin Ьiology had oЬviously

467

468

Саstlе Ьееn strongly irrflr.rеnсеd Ьy an intеrеst in naturlll history that Ьеgаn as a young Ьoy Ьut Ьесat-t-tе fully dеvеlgiсalСluЬ. Although Сагson rеtirеd frсlm offiсial dutiеs at thе Univеrsity of Hawaii's Dеpartmеnt of Gеnеtiсs in 1985, hе was still vеry aсtivе in rеsеarсhand сontinuеd to makе signifiсant сontriЬutions to еvсlllttionаry Ьiologу. Hе is сonsidеrеd to hаvе Ьееn onе of tlrе Urrivегsityof Hawaii's most ешillеnt sсiеntists. Не was a mastеr tе:rсhеrwhtt, in thе сoursе of his distinguishеdсаrееr' gavе of l.rimsеlfunsеlfishly tс>his сollеaguеsand to his malrv studеnts. Modеsty is a virtuе unparallelеd in this grеat sсiеntist.Onсе' whеn hе was Ьеing intеrviеwеd Ьy thе nеws mеdia during a syrnposium hеld in honor of his rеtirеmеnt,hе сommеntеd thаt..it's vеry humbling. Sсiеnсеis a sсlсialеnd е а v o r .T h е r е i s r r o l е а d е r .I d е а s с o m е f r с l m е v е r y w l r i с l r с l i r е с t i o n . . . . T l r е most gratifying part of all is to sее how it [thе Нawaiian Drosoplrila Projесtl has affесtеd thе livеs сlf so many kamаaina [Harvaiiаn word for loсals] studеnts'' (Hoпolulu Stаr Bullеtiп, .|unе 12, 1985). Indееd' Сarson's Hаwaiian Drosophila Projесt has Ьееn an iпrportant trаining gгound for morе rhаn 400 undеrgraduatе,gr:rс1uatе' аnd postgrаduatеstudеnts irr all аspесts of еvoluAlso, tionaгy Ьiology. morе thatr 70 sеnior sсiеtltistsfrсlm all ovеr thе world havе partiсipatеd in the projесt primarily Ьесausеof Сarson,s lеadеrship in thе fiеld of еvoluti
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Сastlе, William F,. (1867-1962) !Иilliam Е. Сastlе, a profеssorat Harvard Univеrsity аnd latеr at thе BttssеyInstitlltion (an agгiсtrlrtrrаl arm of Harvаrd), сontriЬr'rtес] muсh tсl thе еilrlv yеars

of gеnеtiсs.Likе mаny с ing to proЬlеnrs of hеге ginr-ringof thе twеntiеth hе was also thе first to u thе еvolutionist's wоrkh won thе NoЬеl Prizе for Сastlе's most famotls аnd whitе сoat сoloгs (

pеrimеnts that showеd populatiоn' from mixс 'W'hat w: Phillips 7914). r thе finishеd, was tion point асhiеvеd' In othr сlaimеd and what rrran pеrtnanеnt еffесts on th work provеd that onсе : thе starting point. Throughout thе twеn slrowing that sеlесtion r h o u g h С а s t l е . sw o r k i W a ) .г o m o d е r n е v o l u t pеrirnеnt intеnding to s first inrеrеst was in thе sllрposеs. Сastlе wirs tr gеnеs' arе not еntiге an up irs rеproduсtion Oсс timе. It was only aftеr } thе сеntury that Саstlс fronr vаriаtions саusе transmittеd unсhangеd Ir-rthе сoursе of his mous and important ol ( s е еP г o v i n е 1 9 8 6 ) . I n z сhе foundеrs of modеr rеsеarсh work was on t tеl.еstthat wеnt Ьilсk t(

в|BLIoGRAPHY

Саstlе,W. Е.' аnd J. с. РI Теst оf thе Еffесtit'е \ Мeпdеliап Cros-sс,s Pror,inе,W. B. 1986.Sap оf СhiсagсlPrеss. Rusе.A4. 1996.Мoпаd tr СirmЬridgе,MA: Hа

Саstlе latural history that bеgan as a oung сollеgеstudеnt mеmЬеr of еs at thе Univеrsity of Hawaii's vеry aсtivеin rеsеarсh and сono еvolutionary biology. Hе is y o f H r w a i i . sm o s t е m i n е n ts с i ) сoursеof his distinguishеd сaguеs аnd to his many studеnts. rt sсiеntist.onсе, whеn hе was ' a symposium hеld in honor of humЬling.Sсiеnсеis a sсlсial еnеvеry whiсh dirесtion. . . . Thе е Hаwaiiаn Drosсlphila Projесt] [Hawaiian word for loсals] stu8 5 ) .I n d е е d ,С a r s o n ' s H a w a i i a n ining gror.rndfor morе than 400 studеntsin all аspесts of еvolu' сiеntistsfrсlm all ovеr thе woгld lсausеtlf Сarson's lеadеrship in lility tо Ьring togеthеr thе Ьеst . 'w h o h а s Ь е е nа Ь l е t o m o t i v а t е lns to unloсk thе sесrеtsof еvorink аЬout how knowlеdgе сan :1nеt.Thеsе qualitiеs madе this

dings. 1989. Hаmpton Lawrеnсе .W. y. In W. Andеrson, K. Y. s, Spесiаtkltt'апd tbе Fсlипdеr y Prеss. ] е wY t l r k :С о | u m l ' i а U n i v е r s i t y f spесiеs.Sсiепсе 168: 1'414_141'8' S. Karlin аnd Е. Nеvo, еds., ). orlandо, FL: Aсadеmiс Prеss. о n :J o h n М u r r a y . rеvolutionsin miсroеvolution аnd Andеrson,K. Y. Kanеshiro, and d thс FtluпdеrPriпсiplе, 4з_76.

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vеrsityand latеr at thе Bussеy InltriЬutеdmuсh to thе еarly yеars

of gеnеtiсs.Likе nrany of his gеnеration, hе Ьеgan as an еmЬryologist, switсhing to proЬlеms of hеrеdity whеn Mеndеl's work was rеdisсoverеd at thе Ьеginning of thе twеntieth сеntury. Сastlе workеd mainly оn mammals, although hе was also thе first to usе thе fruit fly Drosophilа mеlапogаstеr,whiсh bесamе thе еvolutionist's workhorsе in thе twеntiеth сеntury. Thomas Нunt Morgan Won thе NoЬеl Prize for dесiphеring thе gеnеtiс naturе of this organism. Сastlе's most famolls sеriеs of ехpеrimеnts Wеrе on rats of varying Ьlaсk and whitе сoat сolors (sее figurе on pаgе 47О). |1е pеrformеd sеlесtion еxpеrimеnts thаt showеd how onе сould сhangе thе ovеrall rangе of huеs in a population, from mixеd to virtually еntirеly whitе or Ьlaсk (Сastlе and Phillips |91'4)..Whatwas signifiсantaЬout this work wаs thаt onсе thе sеlесtion was finishеd, thе гаts' сoat сolors сontinuеd to hovеr аround thе final point aсhiеvеd. In othеr words, Сastlе showеd what Сharlеs Darwin had сlaimеd and what many сritiсs had dеniеd: selесtion сan havе lasting if not pеrmanеntеffесtson thе ovеrall naturе of a population of organisms.Сastlе's work provеd that onсе sеlесtionis rеlaхеd, еvеrythingdсlеsnot rеvеrt Ьaсk to thе starting point. Throughout thе twеntiеth сеntury thеrе wеrе numеrous othеr ехpеrimеnts showing that sеlесtion сan hаvе lasting еffесts. Paradoхiсally, howеvеr, although Castlе's work is rightly hailеd as a major еxpеrimеntal stеp on thе Way to modеrn еvolutionary thinking, hе himsеlf did not еntеr into thе ехpеrimеnt intеnding to slrow thе worth of sеlесtion. Rathеr, as a gеnеtiсist' his first intеrеstwas in thе nаturе of thе hеritaЬlе faсtors that Mеndеlism prеsupposеs.Сastlе was trying to show that thеsе faсtors, what arе now сallеd gеnеs'arе not еntirе and unсhangеaЬlеin thе сoursе of gеnеration' Ьut split up as геproduсtion oссurs and rесomЬinе in nеw variations in thе сoursе of timе. It was only aftеr Morgan's work was сompletеd in thе sесond dесadе of thе сеntury that Сastlе сonсеdеd that hе had Ьееn wrong and that (apart from variations сausеd Ьy spontanеous сhаngеs' or mutations) gеnеs arе tгansmittеdunсhangес. In thе сoursе of his long сarеег, Сastlе had many studеnts' thе most famous and important of whom Was gеnеtiсist and еvolutionist Sеwall \Х/right (sееProvinе 1986).In anothеr paradox, Wright is propеrly known as onе of thе foundеrs of modеrn еvolutionary thought, yеt thе Ьulk of his еmpiriсаl rеsеarсhwork was on thе pattеrnsof hеrеdity as shown Ьy guinеa pigs' an intеrеstthat wеnt Ьасk to his studеntshioundеr Сastlе. в|вLloGRAPHY .W.. Сastlе, Е., and J. С. Phillips. |L)14.Piеbаld Rаtsапd Sеlесtioп:Ап Ехpеrimепtаl Теstof thе Еffесtiuепеss сlf Sеlесtioпапd of thе TЬесlrуof GаmetеPuritу iп .lfashington. .Washington, МепdеliапСrosses. DС: СarnеgiеInstitutionof Biologу.Сhiсago:Univеrsity Рrovinе,!и. B. 1986'SеtuаllWrightапd Еuсllutioпаrу of СhiсagoPrеss. Rusе,М. 1996. Мoпаd to Мап: Тhе Сoпсеptсlf Progrеssiп ЕuolutiсlпаrуBiсllogу. СamЬridgе, МA: Harvаrd Univеrsity Prеss

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469

470

Саstle

fifrфq f, T т'r

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The Саusesof I (i J.B.s.Haldanе's tеxt сapstonе is thе hailеd primarily for сhitесts of populati ( 1 9 3 1 ) ,a n d Н a l d а n a synthеsis of сlassir сhеmistry rvith popr disсussion is сonfinе iсal nratеrial drawn AЬеrystwyth, еntitlе Haldanе's proЬlеr саnсе of natural sеlе shaгеs thе proЬlеrna answеr) intеrwovеn part follows Fishеr i dt1е to low sеlесtion danе's support сlf Fis

саrriеd thе Inathеml сhanging еnvlrоnmс and in part as a сrlt ovеr, and important lесtion, rес
Thеsе disсussiоns diх of Саusеs. Y|a| саusеs of within- an tеrs and a Ьroad аss

WillianrСastlе,sdеmonstrаtionoftЬееffесtsofsеlесtitrnforсoatсo1or.Тop r o L u : | Ь e с с l a t с o l o r . . . t . u , " d f o r с l a s s i f i с a t i o n . М i с l r l t еЬr оthаt l z : sСastlе's е l е с t i owork n-forlight сolоr. Thе pаradоx сo|or.Btlttrlпt,ulz'.,.t....l. r",Ъ...t tЬat thе units оf *еnеtiсs(Ьv showing was aimеd at disp.ov,nj й.'"r.rй of natrtral еffесts thе .."^.::pJ:u.c hеrеdity Ьlеnd in еaсh gеnеrаtigl), 1 . ) P l а t е С a s t l еa n d P h i l l i p s l 9 1 4 , '.-йiЬ.tг'om

nal сhаrptеr. .Working througЬ t еry of Mеndеlism in and bеtwееn spесiе pаraЬlе 1oсi, diffегеn mosomеs' or o{ whс Gепеtics апd thе Ol guе thаt thе samе s

within spесiеsассou Ьroadеns thе Меndt Thе сonсlusion о thought sinсе Darw thе sarnе timе, Hal dominant сrеativе { сrеativе сausе.Тhrс

еvolution, inсludin5 that mirrds arе surе

Thе Сausеsof Еvolutiоn +4

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! I

. sеlесtionfor сoat сolor. Top Мiddlе rop: sеlесtionfor light 'е paradoхis that Сastlе'swork y shоwingthat thе units of ng thе еffесtsof natural l.)

Tbе Саuses of Еuolutioп (I. B. S. Haldanе) J. B. s. Haldanе's (7892*1964) The Саиses of Еuсllutioп' puЬlishеd tn 1932, is thе сapstonе tехt in thе origins of thеorеtiсal pоpulation gеnеtiсs. Саusеs is hailеd primarily for its important, сritiсal disсussion of thе work of thе arсhitесts of population gеnеtiсs' R. A. Fishеr (1930 [195s]), Sеwall \й/right (1931),and Нaldanе himsеlf. It is lеss widеly, yеt just as dеsеrvеdly,hailеd as a synthеsisof сlassiсаl gеnеtiсs,сhromosomal mесhaniсs' сytology, and Ьioсhеmistry with population gеnеtiсs.This is ironiс Ьесausеthе mathеmatiсal disсussionis сonfinеd to an appеndiх addеd to original disсussionsof Ьiolog.W.alеs, iсal matеrial drawn from Haldanе's 19З1 lесturеsat thе Univеrsity of ..A Abеrystwyth, еntitlеd Rееxamination of Darwinism.'' Haldanе's proЬlеmatiс may Ье posеd as, ..What is thе naturе and signifiсanсе of natural sеlесtionin Mеndеlian populаtions?'' In this sеnsе,Haldanе sharеsthе proЬlеmatiс of his сontеmporariеs Fishеr and \й/right.And in his answеr, intеrwovеn with supporting еmpiriсal еvidеnсе, Haldanе in largе part follows F.ishеrin thе viеw that сumulativе еvolutionary сhangе is mostly duе to low sеlесtion prеssurеsасting on mutations of small еffесt. But Haldanе'ssupport of Fishеr is not in thе form of an unсritiсal summary. Нaldanе сarriеd thе mathеmatiсal ехploration of sеlесtion in finitе population sizеs, сhanging еnvironmеnts, and multiplе dimеnsions furthеr thаn Fishеr had, and in part as a сritiсаl сonsidеration of !Иright,s work on thе topiс. Morеovег, and impсlrtantly,Haldanе emphasizеd thе problеm of thе units of sе. lесtion, rесognizing that sеlесtivе forсеs aсting on gamеtеs' organrsms' Or populations may сomе into сonfliсt. Thеsе disсussions arе сarriеd orrt in thе middlе сhaptеrs and thе appеndiх of Сацsеs. Haldanе еmЬеds thеm in а riсh disсussion of thе gеnеtiс сausеs of within- and Ьеtwееn-spесiеsdiffеrеnсеsdisсussеd in еarliеr сhaptегs and a Ьroad аssеssmеntof thе sсiеnсе of еvolution as а wholе in thе final сhaptеr. \Vorking through еmpiriсal еvidеnсе amassеd from thе timе of thе rеdisсovеry of Mеndеlism in thе 1900s, Haldаnе dеmonstratеs thаt diffеrеnсеs within and Ьеtwееn spесiеs arе duе to diffеrеnсеs Ьеtwееn individual gеnеs at сomparaЬlе loсi' diffеrеnсеs in numЬеr of individuаl сhromosomеs or sеts of сhromosomеs' or of wholе сlrromosomеs. Antiсipating Thеodosius DoЬzhansky's Gепetics апd thе origiп of Speсies (19з7), Haldanе usеs this еvidеnсе to arguе that thе samе sorts of proсеssеs that aссount for thе gеnеtiс diffеrеnсеs within spесiеs aссount for suсh diffеrеnсеs Ьеtwееn sресiеs. Furthеr, Haldanе Ьroadеns thе Меndеlian сontеxt of еvolution. Thе сonсlusion of Саusеs еmphasizеs thе progrеss madе in еvolutionary thought sinсе Darwin and thе powеf of еvolutionary ехplanations of lifе. At thе samе timе. Hаldanе is сlеar that whilе hе sееs natural sеlесtion as thе dominant сrеativе еvolutionary саusе, hе doеs not сlаim that it is thе only сrеativе сausе. ThrougЬout Саиses Haldanе highlights thе multiplе сausеs of еvolution, inсluding dеvеlopmеntalсonstraints сln еvolution. Haldanе insists that minds arе surely produсts of еvolution;thеy also arе in all likеlihood not

471

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СаuаlliSforzа pгoduсts of naturаl sеlесtion.Thе Ьroad disсussion in Haldаnе's сonсluding сhaptеr is to еmЬеd thе sсiеnсеof еvolution in а distinсtly matеrialist philosophy of sсiеnсе. .sfright Haldanе, similar to Fishеr and Ьеforе him, aссomplishеd а гесonсiliation of natural sеlесtion and Mеndеlian hеrеdity. Нaldanе forgеd ahеad of his prеdесеssors Ьy furthеr synthеsizing a widе swath of Ьiology with p
-R.А.s.

Cavalli-Sfо rza, Luigi Luсa (t. |922) Luigi Luсa Cavalli-Sforzа сan Ье сonsidеrеda modеrn rеinсarnati
G e n e s \ 1 9 9 4 )f r through in thе r rесonstruсtion whiсh thеy spr graphiс distriЬu riginal populati еvolutionary hil In Тhe Neolith (1984|' hе had l to thе sprеad o sсalе with spес guagе diffеrеnti guagе сlаssifiса distriЬution of sсalеs. Givеn thе brr grеat dеal of Wс that might hеlp Тrаnsmissiсlп аl Сavalli.Sforz сеntly his laЬor tion usеd to dе Thе study of th сially еffесtivе il Cavalli-Sforz sеarсh. Hе is tI сolumns. Thе t with W. Bodmе fiеld in 1981.

B|вLloGF

Сavalli.Sforza, L. Gепеtiсsоf I Сavalli-Sforza, L. San Frаnсisс Cavаlli-Sforzа, l,. Еuсllutioп,P Саvalli-Sforzа, L. of Humап G Сavalli.Sforza,l-. GепеtiсDrif'

СhamЬеrs, t

RoЬеrt СhamЬс Britain. Togеtht abjесt povеrty

Сhаmbers сussionin Наldanе's сonсltrding in a distiпсtlymatеrialist philosforе him' ассomplishеd a rесon_ hеrеdity.Haldanе forgеd ahеad rvidеswath of Ьiology with pop. part and parсеl оf thе origins o{ lat is сommonly сallеd thе mod. е r . i t i s g г o u n d Ь r е а k i n gi n i t s

f Spесiеs.Nеw York: Сolunrbiа у оf NаturаISеlесtitllt.2ndеd. Nеw . l,ondon: Lоngmans. tions. Gепсtiсs |6: 97_1'59.

-R.А.s.

)\ ] a modеrn rеinсarlrationof a Rеto еvolшtionaryЬiolсlgy еmегgеd angе of fiсlds that hе сultivatеd at otr for undегstandingthе human е 1940s,hе Ьriеfly praсtiсеd mеdsе;rrсh'Attгaсtеd Ьy thе statistiсal цndеrthе guidanсеof R. A. Fishеr rmе timе (in thе еarly 1950s), hе . i а l s е х .a h i g h l y i n n o v a t i v еt o p i с . эutеd lasting mеthodologiсal ad'_Еdwardsgеnеtiс distanсе, an еsэgrаphiс studiеs (irnothеr fiеld hе gгaphyof gеnеs',). е riсhnеssof historiсal rесords in . dispеnsations)in lrurnan popula. lutionary sсiеntiststo Ьеliеvе that пrrranpopulations. In 2ОО4, Сoпiп ltаlу' organiсirlly prеsеrrtеdthе г of gеnеtiсsat StarrfordUnivеrsitу зmеritusprofеssor. эf modеrn human gеnеs for rесonLlistсlrуапd Geographу of Humаn

Gепеs (1994) fittingly slll.Ilsthе Ьrеadth of lris еndеаvor. Hailеd аs а brеak. through in thе urrdеrstanding of human еvolution, it offеrs thе first full-sсalе rесonstruсtion of whеrе humаn populations originatеd аnd thе paths Ьy whiсh гhеy sprеаd throughout thе world. By mapping thе worldwidе gеographiс distriЬution of gеnеsfor ovеr 110 traits in ovеr 1'800 primaгily aЬoriginal populations' migгations weге сhartеd and а сloсk was dеvisеd to datе еvoiutionаry history. Еssеntial information was соntriЬutеd by arсhеology. In Thе Nеolithic Trапsitioп апd thе Geпetiсs of Popиlаtioпs iп Еurсlpe (1984)' hе had addrеssеdthе quеstion of wЬеthеr сultural diffusion was duе to thе spгеad of idеas or of pеoplе. Thе issuе was invеstigatеd at a world sсalе wiгh spесial attеntion to thе link Ьеtwееn gеnеtiс divеrsity and languagеdiffеrеntiation.Although linguists havе not rеirсhеdсonsеnsuson languagе сlassifiсation at а gloЬal sсalе' an intriguing ovеrlap bеtwееn thе distriЬution of gеnеs and languagеs Was found at diffеrеnt gеographiс sсаlеs. Givеn thе brеаdth of his rеsеarсh intеrеsts, it is not surprising to find a grеatdеal of woгk сollесtеd in a Ьook dеdiсatеdto thе ехploration of modеls that miglrt hеlp us undеrst;rnd how сultur:rl traits trrе trаnsmitted (Сulturаl Trапsmissionапd Еuolutiсlи' сoallthorеd with М. w. Fеldman' 19s1). Сavalli.Sforzа has еnjoyеd a rеmarkaЬly сrеativе sсiеntifiс longеvity. Rесеntly his laboratсlгy dеvеlopеd nеw tесhniquеs for disсovегing DNA variation usеd to dеfinе nеw gеnеtiс markеrs of thе Y and othеr сhromosomеs. Thе study of thеsе unipаrеntally tгansmittеd markегs tцrnеd out to Ье espесially еffесtivеirr еluсidаting popr:lation origins. Cavalli-Sforza has а natural gift for сommuniсating his passion for rеsеarсh. Hе is thе author of mаny gеnеral audiеnсе Ьooks and nеWspapеr сoluпrns. Thе tехtЬook The Gепetiсs of Humшt Populаtioпs (сoauthorеd with !И. Bodmеr, 1971| was awardеd a prize as thе most quotеd tехt in thе f i е l di n 1 9 8 1. вIвLIoGRAPHY Сavaili.S{oгza, L. L.' and A. Ammеrman.,l,984.Тhе NeolithicТrапsitioпаnd tbе Gепеtiсso|-Populаtiotlsiп Еиropе. Prinсеton,NJ: РriпсеtonUnivеrsityPгеss. .W. Сavalli-Sforza,L. l-., аnd Bodmеr. 1971.Тbе Gепеtiсsof Humап Populаtioпs. SanFrаnсisсo:W. H. Frееmаn;Мinеola,NY: DovеrPuЬliсаtions. Сavalli-Sforza, L. L.' and М. W. FеIdmаn.198l . СulturаITrаnsmissiсlп апd Еuolutklп,Prinсеton'NJ: PrinсеtonUnivеrsityPrеss. Саvalli-Sforza,L. l-', P. Меnozzi, andА.Piazza. 1994. Тhe Historу аnd Gеogrаphу of 17t,ttпап Gепеs,Prinсeton,NJ: PrinсеtonUnivеrsityPrеss. Сavalli-Sforzа, L. L., A. Мoroni, and G. Zet.2ОО4,Сoпsапguinitу, Iпbreeding, апd -P.М' GепеticDrift iп [tаlу.Prinсеton,NJ: PrinсеtonUnivеrsityPrеss.

СhamЬеrs, RoЬеrt(Is02_1s7I) RoЬеrt Сhambеrs Was ol-lе of tlrе most suссеssful Ьusinеssmеn in Viсtorian Britain. Togеthеr with his Ьrothеr, William, hе had pullеd himsеlf up from abjесt povеrty to found a thriving puЬlishing businеss. Thеy wеrе major

47З

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Сhаmbеrs innovators in thе usе of stеam prеssеs' and thеy wеrе at thе forе of thе produсtion of popular litеraturе and magazinеs. A wееkly puЬliсation, СhamЬers,slournal of Literаtиrе, Sсiепсе апd Arts, of whiсh RoЬеrt and William wеrе сoеditors and to whiсh RoЬеrt сontributеd many smаll piесеs,Wasvеry suссеssful. RoЬеrt СhamЬеrs was always rеady with his pеn. Hе wrotе Ьooks and artiсlеs as wеll, mainly of a popular and (with an еyе to salеs) informativе, gossipy naturе. Primе ехamplеs inсludеd guidеs to walks around Еdin. Ьurgh, listing plaсеs whеrе sеnsational murdеrs and othеr ill dееds had oссurrеd in past years-pеrfесt matеrial for a family faсеd with thе nееd to fill thе long hours of yеt anothеr Sсottish Sundaу. As wеrе many othеr half-еduсatеd mеmЬеrs of soсiеty, СhamЬеrs was also vеry intеrеstеdin sсiеnсе, partiсularly gеology. In thе еarly 1840s, this lеd him to writе what was to Ьесomе onе of thе sеnsational works of thе еra, Vеstigеsof thе Nаturаl Historу of Сreаtioп (1.844),togеthеr with a sеquе1titled Ехplапаtioпs (1845). Apparеntly, СhamЬеrs had sеt out to writе a Ьook on phrеnology (thе sсiеnсе of Ьrain Ьumps), anothеr popular psеudosсiеntifiсtopiс of thе day' Ьut hе got sidеtraсkеd into writing a Ьook on еvolution. (SееFigurе 3 in thе main еssay ..Thе Нistory of Еvolutionary Thought'' Ьy Miсhaеl Rusе for dеtails of thе way that СhamЬеrs сonсеivеd of thе еvolutionary proсеss.) Givеn thе сontеnt of Vеstiges' it was сеrtainly not intеndеd as a сall to athеism, Ьut morе an appеal to thе lawlikе naturе of thе world. (Although СhamЬеrs was not kееn on rеgular сhurсhmеn, hе was always a Ьеliеvеr in a dеistiс way.) In сommon with many othеr еvolutionists' his Ьook wаs a hymn оf praisе to progrеss. As wе havе improvеmеnt in thе sосial world' so also do wе havе it in Ьiology' and сonvеrsеly as wе havе improvеmеnt in thе Ьiоlogiсal world, so also do wе havе it in thе soсial. Bесausе of his Ьцsinеss and soсial position, СhamЬеrs wеnt to grеat lеngths to сonсеal his authorship. Indееd, it was not rеvеаlеd offiсially until 1884, aftеr his dеath. It was proЬaЬly as wеll that hе hid his namе' Ьесausе Vеstigеs was highly сontrovеrsial. Мany in thе sсiеntifiс сommunity wеrе еxtrеmеly сritiсal, lеading Сharlеs Darwin, just thеn formulating his еvolution. ary thеory' to kееp quiеt aЬout his own aсtivitiеs. Нowеvеr, thеrе wеrе many who rеspondеd positivе|у to Vestiges, most notaЬly poеt Alfrеd Lord Tеn..In Меmoriam,'' a triЬutе to thе nyson. Не was сomplеting his long poеm mеmory of his dеar friеnd Arthur Hallam. Dеprеssеd by what hе saw as thе еmpty nihilism of Lyellian uniformitarianism-no сhangе, no progrеss-hе drеw сomfort from thе optimism of Vеstiges' with its support of progrеss. Pеrhaps it was that thе dеad-too.young Hallam Was a supеrior Ьеing Ьorn Ьеforе his timе. (Sее thе alphaЬеtiсal еntry on Vеstigеs for dеtails.) Vestiges madе thе idеa of еvolution wеll knоwn in thе mid.Viсtorian еrа and pavеd thе way for Darwin and his oп thе Оrigiп of Speсiеs. By thе timе the origiп appеarеd, sсiеntists and laypеoplе wеrе ехhаustеd from arguing, thе shoсk of thе idеa of еvolution WаS ovеr' and a morе Ьalanсеd aссount of сhangе сould Ье graspеd and aссеptеd Ьy many.

вlвLIoGRAPнY

ChamЬеrs' R. l844. Vсs/lдс |845. ЁхpIапаli,'пs Darwin, с. 1859. Оп thе ()r

Rusе' М. 7996. Мoпаd to М СamЬridgе, МA: Harva Sесoгd, J. A. 2000. viс!оriап апd Sесrеt Аиthorship tl Сhiсago: Univеrsitv of ( Tеnnyson' A. 1850. In Меm. Аutb oritаtiuе Техt Bасk Norton.

Chanсе and еvolutiо

T h е с o n с е p гo f с h а n с еi s l T h е s е a s s o с i а t i o n sr a n g е tanсе to playing a сеntra molесular Ьiology. Thrее lutionary thеory arе disсr D a r w i n 1 8 5 9 , 1 3 1 ) ,с h a r and maсroеvolution. Wit disсussеd. Howеvеr, trеa arе Ьеyond thе sсоpе of t It is imPortant to not dееp, mеtaphysiсal sеnsе of сhanсе is most oftеn rl suсh as in quantum mесl fair сoin is prediсtеd stс Thе rеsult has a сausal t сoin flip arе not random disсussions of сhanсе r

mесhanisms. Natural sеlесtion is thr lution. It was, in part, f from rival thеoriеs and l

I y i n g o n с h а n с еm U t а t i o adaptivе сomplехity of t spесiеs ехhibit сhanсе v dеlеtеrious. Bеarеrs tlf s thus thеy rеproduсе anr ovеr timе, thе suссеssf gumеnt thаt сhаnсе vaI struсturе as сomplеx as o f D a r w i n i a nе v o l u t i o n t 1 s 1 9 ] ) a r t i с u l a t е dt h i s world that was a геsul

Сhапсе апd L,uoltttioп

:IеyWеrе at thе forе of thе pro. A wееkly puЬliсation' Сham. \William ;, of whiсh RoЬеrt and tеd many small piесеs,was vеry r his pеn. Hе wrotе Ьooks and l t h а n е y еt o s a l е s )i n f o r m a t i v е ' guidеs to walks around Еdindеrs and othеr ill dееds had oсr family fасеd with thе nееd to Sundaу. As wеrе many othеr еrs Was also vеry intеrеstеd in 840s,this lеd him to writе what s of thе era, Vestigеs of thе Nаtlith a sеquеl tit|edЕхplапаtioпs 'е a Ьook on phrеnоlogy (thе sсidosсiеntifiсtopiс of thе day, Ьut olution.(SееFigurе 3 in thе main t'' Ьy Мiсhaеl Rusе for dеtails of :volutionaгyproсеss.) Givеn thе 'tеndеd as a сall to athеism, Ьut world. (Although СhamЬеrs was ays a Ьеliеvеrin a dеistiс way.) In .s Ьook was a hymn of praisе to эсial world, so also do wе havе it гovеmеntin thе Ьiologiсal world, sition' Сhambеrs wеnt to grеat it was not rеvеalеd offiсially until ,,еllthat hе hid his namе' Ьесausе thе sсiеntifiссommunity Wеге еxrstthеn fоrmulating his еvolutionivitiеs.Howеvеr' thеrе Wеrе many st notaЬly poеt Alfrеd Lord Tеn..In Mеmoriam,'' a triЬutе to thе DеprеssеdЬy what hе saw as thе ism_no сhangе, no progrеss-hе lges,with its support of progrеss. {allam was a supеrior Ьеing Ьorn on Vеstigesfor dеtails.) ll known in thе mid-Viсtoriаn ега t the origiп of Speciеs. By thе timе l p l е w е r е е х h a u s t е df r o m a r g u i n g . .r' and a morе Ьalanсеd ассоunt of mаny.

BIBLIOGRAPHY СhamЬеrs, R. l 844' Vеstigеs rlf the Nаturаl Historу сlf Сrеаtioп. London: Сhurсhill. .,Vеstigеs 1845. Ехplапаtiсlпs: А Sequеl tсl сlf Сrеаtkltt.'' London: Сhurсhill. 1859. of Darwin, с. Оп thе origin Speсies.Lоndon: John Murray. Rusе, М. 1'996. Мoпаd to Мап: Тhе Сoпсеpt of Prсlgrеss iп Еuolutioпаrу Biologу. СamЬridgе, МA: Hаrvard Univеrsity Prеss. Sесord'.I. A. 2000. Viсtсlriап Seпsаtiсln:Тhе Ехtrаordiпаrу Publiсаtioп, Rсссptitlп, ,,Vеstigеs апd Sесrеt Authorshi1l сlf сlf thе NаtиrаI Historу of Сrеаtioп.'' Сhiсago: Univеrsity of Сhiсаgo Prеss. Tеnnyson'A. 1850. In Меmoriаm. In R. H. Ross, еd., lп Меmсlriаm: Ап Аиthoritаtiuе Техt Bасkяrс-luпdsапd Soиrсеs Сritiсism,3_90. Nеw York: -М.R. Nortоn.

Сhanсеand еvolution Thе сonсеpt of сhanсе is аssoсiatеdwith еvolutiоnary thеory in sеvеralways. Thеsе assoсiationsrangе from Ьеing оf historiсаl and philosophiсal importаnсе to playing a сеntral rolе within tесhniсal dеЬatеs in еvolutionary and molесulаr Ьiology. Thrее gеnеra1domains whеrе сhanсе is еmployеd in еvolutionary thеory arе disсussеd:Сharlеs Darwin's usе of сhanсе (for еxamplе, Darwin 1859, 131), сhаnсе and miсroеvolution (random drift)' and сhanсе and maсroеvolution. Within еaсh саmp sеvеrаl finе-grainеddistinсtions arе disсussеd.Howеvеr, trеatmеntof thе morс tесhniсal aspесtsof random drift arе Ьеyond thе sсopе of this еntry. It is important to notе that Ьiologists gеnеrally do not usе сhanсе in a ..Llnсаusеd.''Thе unсausеd sеnsе dееp,mеtaphysiсal sеnsе,suсh as mеaning of сhanсе is most oftеn raisеd in philosophiсal disсussionsof indеtеrminism, suсh as in quantum mесhaniсs. For ехamplе, thе randоm rеsult of flipping a fair сoin is prеdiсtеd stoсhastiсally, Ьut it is dеtеrminеd Ьy physiсal laws. Thе rеsult has a сausal story' so thе undеrlying proсеssеsthаt dеtеrminе a сoin flip aге not random, or stoсhastiс,in a dееp sеnsе.Likеwisе in Ьiology, disсussions of сhanсе rarеly еntail thе indеtеrminaсy of thе urrdеrlying mесhаnisms. Natural sеlесtionis thе privilеgеd mесhanism of сhangе in Darwinian еvolution. It Was' in part' Darwin's usе of сhanсе that distinguishеd his thеory from rival thеoriеs and worldviеws. Darwin dеsсriЬеd a natural proсеss' rеlying on сhanсе mutations and natura1sеlесtion,whiсh сould aссount for thе adaptivесomplехity of thе Ьiologiсal world. In this proсеss' individuals of a spесiеsеxhiЬit сhanсе variations, somе of whiсh arе Ьеnеfiсial and othеrs dеlеtеrious.Bеarеrs of suссеssful traits arе moге fit thаn thеir сompеtitors, thus thеy rеproduсе аnd pass on thеir gеnеs to offspring at a highеr ratе. ovеr timе, thе suссеssfultraits sprеad to аll mеmЬers of thе spесiеs.Thе argumеntthat сhаnсе variations сould offеr thе raw matеrial for еvolving a struсturеas сomplех аs a vеrtеЬratееyе sееmеduntеnaЬlе to the opponеnts of Darwinian еvоlution. Thе famous Еnglish apologist William Pаlеy (1802 [1819])аrtiсulatеd this point of viеw whеn hе drеw thе сontrast Ьеtwееn a world that wаs a result of сhanсе and natural proсеssеs or thе rеsult of a

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Сhапсe апd Еuolиtiсlп dеsignеr.To Pаlеy, thе сhoiсе was oЬvious; thе intriсatе сomplехity of fеaturеs suсh as thе еyе was inсompatiЬlе with anything Ьut a dеsignеr,a thеsis сommonly rеfеrrеd to as thе Argumеnt from Dеsign. Darwin's usе of сhanсе variations distinguishеd his idеas not оnly frоm thosе of сrеationists Ьut also from othеr advoсatеs of сompеting thеoriеs of еvolution, partiсularlyJеаn-BaptistеLаmarсk (1809). Aссоrding to Lamarсk, mutations arе dirесtеd toward an organism's nееds; thеy arisе with rеspесt tо thе usе and disusе of an organism'sparts. For еxamplе, giraffе nесks аrе еlongatеd Ьесausе giraffеs strеtсhеd thеm to rеaсh trееtop foliagе. opposing this modеl, Darwinian еvolution сlаims that mutations arе undirесtеd, сhanсе еvеnts;mutations for long-nесkеdgiraffеswеrе just as likеly as mutations for short-nесkеd giraffеs. Howеvеr, onсе nесk-lеngth mutations oссurrеd, thе long-nесkеd giraffеs had a highеr fitnеss valuе, thus sprеading thеir long-nесk gеnеs throughout thе population. Thе сritiсal point in Darwin's argumеnt is that although mutations arisе Ьy сhanсе, it is not Ьy сhanсе that somе individuals survivе and rеproduсе whilе othеrs pегish. Natural sеlесtion distinguishes ЬеtwееnЬеnеfiсia1аnd dеlеtеriousmutations. Есhoеs of thеsе argumеnts еmеrgе in modеrn сritiсisms of Darwinian еvolution that arе foсusеd on thе sееming аЬsurdity thаt сhanсе variations сould еvеr produсе intriсatе struсturеs or wеll-ordеrеd Ьioсhеmiсal pro. сеssеs.Thеsе argumеnts arе Ьasеd on mistakеn idеas of thе rolе of сhanсе that есho thе argumеnts in Darwin,s timе. Fiгst, сhanсе variations produсе raw matеrial that is moldеd by natuгal sеlесtion;without natural sеlесtion to sеt thе dirесtion and spееd of сhangе, сhаnсе variations сould not aссumulatе with еnough spееd to produсе muсh mеаningful сhangе in any struсtuге or proсеss. Sесond, сhanсе aсtually has a spесifiс mеaning with rеspесt to Darwin's сhanсе variations аnd thе gеnеtiс mutations thаt сausе thеm. FIеrе,сhanсе mеans that spесifiс mutations oссur at random with rеspесtto thе еnvironmеnt so that, unlikе thе l,amarсkian argumеnt' mutations arе not dirесtеd Ьy еnvironmеntal fеaturеsor thе likеlihood that thеy will provе usеful. Somе spесifiс mutations arе indееd morе likеly thаn othеrs-for еxamplе, somе mousе сoat сolor mutations arе morе likеly to arisе than othеrs-Ьut thеir potеntial usеfulnеsshas no Ьеaring on thеir likеlihood of appеaring. \Whеnсontеmporary Ьiologists raisе thе notion of сhanсе thеy likеly arе rеfеrring to rаndom drift. Random drift rеfеrs to thе сhangе in gеnеtiс сomposition that oссurs in a population from onе gеnеrationto thе nеxt Ьесausеof thе random sаmpling of gеnеs that oссurs in a finitе population. A familiar ехamplе of random gеnеtiс sampling is thе sех ratio within a family; in thеory, half of thе сhildгеn in a family should Ье Ьoys and half girls, Ьut it is not unсommon for a fаmily of four сhildrеn to сonsist of thrее Ьoys and onе girl Ьесausеof thе random draw of thе sех сhromosomеs.Thе сlassiс illustration o f r a n d o m d r i f t w a s g i v е n Ь y T h e с l d o s i u sD o Ь z h a n s k y ( 1 9 з 7 , 1 2 9 ) ' w h е r е h е dеsсriЬеda sсеnario of Ьlindly drawing Ьalls fгom an urn. Thе Ьalls wеrе сol. orеd diffегеntly, Ьut othеrwisе indistinguishaЬlе.If onе Ьlindly draws Ьalls from an urn and plaсеs thеm in а sесond urn, it is likеly that thе samplе

population of Ьalls nal population-Ьy whеrе thе gеnotypс lесtivе prеssurеs. Thеrе arе two gе a сatastrophе or ot suсh аs a forеst fir сasеs it doеs so indi ganisms. Тhе smal gеnеration may hal lаtion. A similar for сiеs, сan оссur wh poрulation and sta Thе migrating grou ity with thеm. Thе сrеatе a nеw popul land progеnitors, е rolе. This proсеss l importanсе arе link A sесond form o thе nеxt, in all limi akin to DoЬzhanky quеnсiеs сhangе gr allеlе Ьесomеs thе '

oссurs Ьесаusеthе lеlе frеquеnсiеs. Ту mon' and an unсO beсomеs еxtrеmеly сausе allеlеs may Ь whiсh onе will еvеr Sеwall !Иright, r, sponsiЬlе for fusin first to еmphasizеt guеd that thеrе wоr advantagеous for tl of thеsе сomЬinatiс ..shifting Ьalanсе'' .s7right rееr, would 1940s through thе lution (Provinе 198 Thе most influеr сatеd argumеnt for thеory of еvolution wеrе disсovеrеdan glе protеin that sее wеrе two or morе

Сhаnсе апd Еuollttion i; thе intriсatе сomplехity of fеar aIrуthingЬшt a dеsignеr' a thеsis n Dеsign. rguishеdhis idеas not only from Jvoсiltеsсlf сornpеting thеoriеs of :k (1809).Aссording to Lamarсk, 's nеесls;thеy arisе with rеspесt to эr ехamplе,girаffе nесks аrе еlonlсh trееtopfoliagе. Opposing this xutations аrе rrndirесtеd' сhanсе vеrе just as likеly as mutations for k-lеngth mutations oссurrеd, thе luе,tlrrtssprеadingthеir long-nесk с а | p o i n t i n D a г w i n ' s i l г g u n r е n ti s t is not Ьy сhanсе that somе indi.s pеrish.Natural sеlесtion distin11tltа1tlons.

l d е r nс r i t i с i s m sо f D a r w i n i a n е v o a Ь s u г d i г yt h a t с h а n с е v a r i a t i o n s rr wеll_ordеrеdЬioсhеmiсal pro;takеnidеas of thе rolе of сhanсе . First, сhanсе variations produсе llесtiоn;withоut naturаl sеlесtion сhanсе variations сould not aссu:h mеaningfulсhangе in any struс:asа spесifiсmеaning with rеspесt :nеtiс mutations that саusе thеm. rs oссLlrat random with rеspесt to . utаtions аге r n r с k i а nа r g u m е I . l tm thе likеlihood that thеy will provе c morе likеly than othегs-fоr ехns аrе rnorе likеly to irгisе than ; no Ьеaring on thеir likеlihood of notion of сhаnсе thеy likеly arе rе: r sr о t h е с h а n g еi n g е n e t i сс o m p o е gеnеrationto thе nеxt Ьесausе of s in а finitе population. A familiaг lе sех ratio within a family; in thе[ Ье Ьoys and half girls, Ьut it is not o сonsistof thrее Ьoys and onе girl гomosomеs.Thе сlassiс illustration D o Ь z h a n s k (y1 9 З 7 , 1 2 9 ) ,w h е r е h е 'lls from an urn. Thе Ьalls wеrе сolrishаblе.If onе Ьlindly draws balls Ld urn, it is likеly that thе samplе

population of Ьalls diffеrs in frеquеrrсy'witЬ геgard to сolor, from the original populаtion-Ьy сhanсе аlonе. In short, rarrdоm drift dеsсгiЬеsa sсеnario whеrе thе gеnotypе frеquеnсy of a population сhangеs in thе :rЬsеnсеof sеlесtivе prеssurеs. Тhеrе аге two gеnеrаl kinds of random drift: Ьiаsеd sаmpling as а rеsult of a сatastrophе or Othеr norrsеlесtivеЬiasing, and gеnеtiс drift. А сatastrophе' suсh as а forеst firе' may kill a largе portion of a population, Ьut in most сasеsit doеs so indisсriminatеl1,rvith rеspесtto аny pаrtiсular гrаit in thе organisms. Thе sпrаll numЬег of survivors thаt arе lеft to produсе thе nехt gеnеrationmay havе a diffеrеnt gеnеtiс сomposition than thе original popu. lаtion. A sinrilar foгm of drift, thar is, аn аЬrupt сhаngе in gеnotypе frеquеnсiеs, сan oссur whеn a srnall gror.rpof organisms migratе from thе main population and start a nеw onе' suсh as oссurs whеn an island is сolonizеd. Thе migгаtinggroup may only tаkе :r fraсtion of thе original gеnеtiсvariaЬili t y w i t h r h е m . T l r е u n i q u е g е n е г i сs г г u с t u r еo f t h е f i l u n d i n g p o p u I a t i o nс a n сrеatе a nеw popr"rlationthat is гесognizaЬly distinсt fгom its oгiginal' mainland progеnitors!еvеn though natuгal sеlесtioп mаy Ьavе playеd a minimal rolе. Tlris proсеss has Ьееn сallеd thе foundеr еffесt, and argllmеnts for its importаnсеarе linkеd to thе influеnсеof Еrnst Mayr (1954)' A sесond form of randorn drift oссurs grаdually, froпr onе gеnегаtion to thе nехt, in all limitеd populations through indisсrinrinatеgamеtе sampling akin to DoЬzhanky's analogy of thе Ьalls in tlrе urn. Gеnotypе аnd allеlе frеquеnсiеsсhangе gгadually aсross Е]еnеrations'irnd, givеn еnough timе, onе allеlе Ьесomеs tlrе only gеnе in thе populatiсln (that is, it is fiхеd). Fiхation oссurs Ьесausеthе dirесtion of гandom gеnеtiс drift is dеtеrminеd Ьy thе allеlе fгеquеnсiеs.Tvpiсally' a сommon аllеlе is likеlv to Ьесomе morе сommon' and an unсommon onе is likеly to Ьесomе rarе. Еvеntually onе аllеlе Ьесomеsехtrеmеly сommon and thеn Aхеd. Thе сhanсе еlеmеnt rеmains Ье. сausе allеlеs maу Ье еqually сommon' thus rrr:rkingit impossiЬlе to prеdiсt whiсh onе will еvеntually bесomе fiхеd. Sеwall Wright, who along with J. B. S. Нaldanе and R. A. F.ishеrwas rеsponsiЬlеfor fusing Mеndеlian gеnеtiсswith Darwiniar-rеvolution' was thе first to еmphasizе thе rolе that random drift plays in еvolution. Wright arguеd that thеrе wоuld оftеrr Ье diffеrеnt сomЬinations оf gеnеs that would Ье аdvantagеousfor thеir сaгriеrs and that random drift would influеnсеwhiсh of thеsесomЬirrаtionswould еmеrgе and sprеad through a spесiеs(Ii7right's ..shifting Ьalanсе'' thеory of еvolution). Howеvеr' throughout his long сa.!7right rееr, would vaсillatе on thе importanсе of rаndom drift and in thе 1940s through tlrе 1960s hе dеlеgаtеdrandom drift to а minоr forсе in еvol u t i o n ( P r o v i n е1 9 8 6 ) . Thе most influеntial appliсation of gеnеtiс drift-and thе nrost sophistiсаtеd аrgumеnt foг thе rolе of сh:rrrсеin еvоlution-is thе so-сallеd nеutral thеoryof еvolutiсln.As prоtеins and thе DNA sеquеnсеsthat сodеd for thеm wеrе disсovеrеdand ехplorеd, Ьiologistswеrе finding nrany variants of а singlе prсltеin that sееmеd to hаvе еquivalеnt funсtionirrg.In somе сasеs' thеrе Wеrе two or morе variants in :r singlе pоpulation and, in othеrs' diffеrеnt

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Сhаnсe апd Еuolutioп spесiеs wеrе fixеd for diffеrеnt vаriants. Мotoo Kimura rесognizеd that thеsе oЬsеrvationswеrе faсеts of a singlе proЬlеm unitеd Ьy thе сonсеpt of gеnеtiс .$Иright's drift. Hе еxtеndеd original mathеmatiсal work on modеling of gеnеtiс drift to show how thеsеpattеrnswould еmеrgе (Kimura 1983). This work lеd, in turn' to using DNA sеquеnсеsas ..molесularсloсks'' and to a rеvolution in undеrstandinghow spесiеs,gеnеra' familiеs, and еvеn еntirе phylа arе r е l a t е d( K i m u r a 1 9 8 3 ) . From a maсroеvolutionary pеrspесtivе'somе Ьiologists arguе that еvеnts suсh as ехtinсtions, spесiеs divеrsifiсation' radiations, and inсrеasing сomplеxity сan Ьеst Ье еxplainеd stoсhastiсally,without rеfеrеnсеto a partiсular саusal story. This is not to say that thеrе arе no undеrlying сausеs to maсroеvolutionary еvеnts, Ьut that stoсhastiс mеthods sееm to сapturе thеsе еvеnts Ьеttеr than dеtеrministiс mеthсlds (Millstеin 2000). For ехamplе, is thе inсrеasing соmplеxity of thе organiс world duе to passivе or aсtivе trеnds, that is, Ьy сhanсе or dirесtеdеvolution? Although it is diffiсult to providе nесеssaryand suffiсiеntсonditions for Ьiologiсal сomplеxity, it is gеnеrally agrееd that lifе originatеd as simplе organisms and grаdually Ьесamе muсh morе сomplех. Bесausе lifе Ьеgan nеar thе minimum Ьoundary o{ сomplеxity, rаndom variation alonе would produсе morе сomplеХ organisms; this would Ье a passivе trеnd. An aсtivе trеnd would Ье ехеmplifiеd Ьy dеvеlopmеntal routinеs or phеnotypiс novеltiеs that drivе еvolution toward inсrеаsing сomplехity, Ьеyond that of сhanсe (Сarroll 2001). A final sеnsе of сhanсе in еvolutionary thеory is that arriving at any paгtiсular еnd point in еvolutionary spaсе is a сhanсе еvеnt. For еxamplе, Stеphеn Gould (1,989)fаmously сlaimеd that humans arе an improbablе еnd point on thе еvolutionary trее;many unrеlatеd (сhanсе)еvеntsсulminatеd in thе ехistеnсе of humans. Gould did not imply that thеrе arе not sеlесtivеrеasons (аmong othеrs) еxplaining thе еvolutitln of humans. Rathеr, hе arguеd thаt humans arе a rеsult of a vast numbеr of improЬaЬlе еvеnts.This is thе sеnsе of сhanсе, attriЬutеd to Aristotlе, whеrе indеpеndеntсausal сhains сomЬinе to produсе an unintеndеd еffесt. A сar aссidеnt, for ехamplе' is аn instanсе of sеparаtесausal сhains сomЬining and produсing an unintеndеd rеsult. BIBLIOGRAPHY Bеatty'J. 1984.Сhanсеаnd naturаlsеlесtion. Phil
Mayr, Е. 1954. Сhangе Hardy, and Е. B. Ft Allеn and Unwin. Millstеin, R. L.2000. (

no.4: 603-624. .!И. Palеy' l1802l 1819. Rivington. .!И. Provinе, B. 1986. Se of Сhiсago Prеss.

Charlеsworth, Br

Briаn Сharlеsworth il 50 yеars. Hе is knowr imеntal work has Ьее for sеvеral rеasons:a tion of thе сonnесtior and numеriсal appro work of othегs, and al Brian Сharlеswortl BA in Natural Sсiеn honors in 1966.He m orah Сharlеsworth' l graduation' Ьoth Сha . studying undеr J. М. Upon rесеiving his with Riсhard Lеwonti an offiсе with Tеd G populations. B.С. rеа lеm; this еffort produl finе fitnеss and dеsсr сhangеs. His Ьook, Е rеmains thе primary s In 7971B.С. was h tiatеd еxpеrimеntal ц sions with D.С. lеd t] сhangеs that affесt tht ifiеrs оf rесomЬinatior immеdiatе rеsult was thаt launсhеd D.С.'s с Thе Сharlеsworths Maynard Smith (B.С. laЬ at thе National ln olina bеgan B.С.'s wor tеr' Janе, Was Ьorn in Aftеr attеnding a sy nеo-Darwinism in 19

Сhаrlеsшorth, Briаn

эo Kimura rесognizеdthat thеsе unitеdЬy thе сorrсеptof gеnеtiс Ltiсalwoгk orr modеling of gеnе_ r е r g е( K i m u r a 1 9 8 3 ) .T h i s w o r k llесularсloсks'' and to a rеvolumiliеs,and еvеn еntirе phyla arе lmе Ьiologistsarguе that еvеnts r а с l i а t i o n sа. n d i n с r е а s i n gс o m . without rеfеrеnсеto a partiсular 'е аrе no undеrlving сausеs to с mеthodssееInto сapturе thеSе u{illstеin2000). For еxamplе, is w o г l d d u е t o p i r s s i v еO r a с t i v е ln? Although it is diffiсult to prol i o l t l g i с асl o m p l с x i t y .i t i s g е n е r rganismsand gradually Ьесamе lеar thе minimum boundary of l produсе morе сomplеx organ/е trеnd would Ье ехеmplifiеd Ьy ltiеs that drivе еvolution tоward : е ( С a r r o l l2 0 0 1 ) . : o r r .i s t h e t a r г i v i n ga t а n y p а r t i с tnсе еvеnt.For ехamplе, Stеphеn s aге an improЬaЬlе еnd point оn се) еvеntsсulnrinatеdin thе еxisrt thеrе arе not sеlесtivе rеasons 'hutlans. Ratheг, hе arguеd that proЬаЬlееvеnts,Tlris is thе sеnsе dеpеndеntсausal сhains сombinе i d е n t ,f о r е х a m p | е .i s a n i n s t а n с е oduсing an unintеndеd rеsult'

hilosophуof Sсiепсе51, no. 2: of morphologiсal :volrrtion .uаr2 v 2 ) :l 1 0 2 _ 1l 0 9 . rdon:JсlhnN{r-rrr;ry. Nеw York: СolumЬiа of Spесiеs. Ьiologyаnd in еvсllutiоnary \аIеапd thе N,tturеr;f Hйrоrr,. Nеw сulаrЕuolиtklz. СamЬridgе: vols.Paris:Dеntu.

Мayr, Е. 1954. Сhаngе оf gеnеtiсеnvironmеnt and еvolution. In J. Нuxlеy, A. С. Hardy, and Е. B' Ford, еds., Еt.'olutionаs а Proсess, 157_180. London: Gеorgе Allеrr and Unwir-r. Мillstеin, R. L. 2000. Сhanсе zrnd mасrоеvo|ution,Philosophу of Sсiеnсe 67, no.4: 603-624. Palеy,W. [1802l 1819. Nаturаl Thеolсlgу (Сollесted Wсlrks' vol. 4). London: Rivington. Prоvinе,W. B. l986. Sеи,аll WrigЬt сlпd Еuollttioпаr1,Biologу. Сhiсago: Univеrsity -].Z. of Сhiсago Prеss.

Сharlеsworth,Brian (b. 1945) Brian Charlеswoгth is onе of thе fЪrеrnostpopulаtion gеnеtiсisrsof thе iast 50 yеars.Hе is krrown primarily for his thеoгеtiсalwork, although his ехpеrimеntal Work has Ьееn suЬstantial. Сharlеsworth's work hаs Ьееn influential for sеvеral rеasons:а willingnеss to takе on diffiсult proЬlеms' an appreсiation of thе сonnесtion Ьеtwееn tlrеory аnd data, сlеvеr usе of mathеmatiсal and numеriсal аpproaсhеs, honеst assеssmеntsof thе shoгtсomings of thе work of othеrs, aпd an unusually Ьroad knowlеdgе of thе sсiеntifiс litеraturе. Brian Сharlеsworth (B.С.) was born in Еngland in 1945 and oЬtainеd his BA in Naturаl Sсiеnсеs from Quееn's Сollеgе, СamЬridgе, with first сlass honors tл |966. Hе mеt his futurе wifе, DеЬorah Malrby (ь. |94З, now DеЬorah Сhаrlеsworth' hеrеaftеr D.с.), in his first уеar at СamЬridgе. Upon graduation,bсlth СharlеswoгtЬs Wеnt on to PhD studiеs at СamЬridgе, B.C. studyingundеr J. NI. Thoday. Upоn rесеiving his dеgrее in |969, B.С. took a postdoсtoral fеllowship with Riсhard Lеwontin at thе Univеrsity of Chiсаgo. At Сhiсago, B.С. shаrеd an offiсе with Tеd Giеsеl, wЬo was simulating еvolution in agе-struсturеd populations.B.C. realizеd thаt hе сould oЬtain analytiсal rеsults on thе proЬlеm; this еffort produсеd a suЬstantialЬody of work that showеd how to dеfinе fitnеss and dеsсriЬе tlrе rеlationship Ьеtwееn gеnеtiс аnd dеmographiс сhangеs. His Ьook' Еuolutiсllt iп Аgе-Strисtured Populаtioпs (1980, |994), rеmainsthе primаry sourсе on thе subjесt. |п 1971B.С. wils hirеd аs a lесturеr at thе Univеrsity of Livеrpool and initiatеd ехpеrimеntal work on thе еvoiution of rесornЬination ratеs. Disсtlssions with D.С. lеd thеm tо study modifiеr thеory' whiсh сonсеrns gеnеtiс сhangеs that affесt thе еvolutionary forсеs aсting on othеr loсi, suсh as modifiегsof rесomЬination, dominanсе' mating systеms,and nrutation rаtеs' Thе immеdiаtе rеslllt was a сollaЬorativе sеriеs of papеrs on Batеsian mimiсry thаt launсhеd D.С.'s сarееr irr еvolutionarу biology. Thе Сharlеswсlrths movеd to sussеx in |974, thanks to еfforts Ьy John Мaynard Smith (B.С.'s РhD ехaminеr).A saЬЬatiсalyеar in Сhuсk Langlеy's laЬ аt thе Nationirl Institutеof Еnvironmеntal Hеalth Sсiеnсеsin North Сarolina ЬеganB.С.'s work on tri1nsposaЬlе еlеmеnts.Tliе Сharlеsworths' daughtеr,Janе, Was born in 1981. Aftеr attеnding a symposium at Сhiсago,s Fiеld Musеum on altеrnativеs to nеo-Darwinism irr 1980, B.С. сoauthorеd a papеr with Monty Slatkin and

479

Сh аrlesulorth,D eb orаh Russ Landе that sharply сritiquеd сhallеngеsto nеo.Darwinism. Thеsе сhallеngеs prinсipally stеmmеd from Stеphеn J. Gould's ехtеnsions of Nilеs Еldrеdgе and Gould's сonсеpt o{ punсtuatеd еquiliЬriunr. TЬis papеr hеlpеd сatapult B.C. from a rеspесtеd ехpеrt on mathеmatiсal thеоry to a lеadеr in t h е f i е l d o f е v o | u t i o n .B . C . h а s s i n с е t а k е n m a n y o г } p o r t u n i t i еtso с r i t i с i z е idеas outsidе orthodoх nеo-Darwinism' frоrn GaЬriеl Dovеr's suggеstionthаt transposaЬlе еlеmеnts might play a сausal rolе in еvolution to rесеnt attеmpts to еrесt a sсiеnсеof IntеlligеntDеsign. Thе Chaгlеsworths movеd to thе Univегsity of Chiсago in 198.5,whеrе B.C. was dеpartmеnt сhair fгom 1986 to \997' The Сharlеsworths' transition to thе study of molесular еvolution Was сеmеntеdЬy thеir 1993 disсovеry, with Мartin Morgan' that dеlеtеrious mutations rеduсе thе аn.rоuntof variation in parts of thе gеnomе with low rесоmЬination. This providеd a novеl ехplanation foг a wеll-еstaЬlishеdpattеrn that was thеn asсriЬеd to thе hitсhhiking еffесts of Ьеnеfiсial mutations. |п t991, B.C. was namеd a Fеllow of thе Royal Soсiеty,whiсh faсilitatеda rеturn to thе Unitеd Kingdom via a Royal Soсiеtу Rеsеarсh profеssorship. B.С. сontinuеs to work primarily in mоlесulаr еvolution and thе еvolLltionof sех сhromosomеs. вIBLIoGRAPHY and dosagе Сharlеsworth,B.1.978.A modеlfor еvolutionof Y сhrоnrosomеs . Proсееdiпgsof thе Nаtioпаl Асаdеmусlf SсieпсеsUSА 7.\: сompеnsation 5618-5622. Ilgsol |994. Еuolution iп Аgе-StruсturеdPсlpulаtioпs.2ndеd. Саmbridgе: СamЬridgеUnivеrsityPrеss. сommеrltarу Сharlеsworth'B.' R. Landе,and Nl. Slatkin.1982.A nеo-Dаrwiniirn on maсroеvolutj'on.Еuoluti on 36: 47449 8, . 199З.Thе еffесtof B., М' T. Morgаn,аnd D. Сharlеsworth Chаrlеsworth, Gепеtiсs|З4: mutаtiоnsоn nеutralmоlесulаrvariatiсln. dеlеtеri
Сharlеswоrth' DеЬorah (b. L94з\ DеЬorah Сharlеsworth (nееМaltЬy) is a pionееr in the study сlf Ьrееdingsys. tеms and gеnomе еvolution. сonсеntratingon how еr'o|uriortmolds sесtions of thе gеnomе to allow thе gеnеs for сomplеx traits to Ье сo.inhеritеd so that thе traits fцnсtion propеrly without thе disruption that rесоmЬination and sеxual rеpгoduсtion might othеrwisе produсе. DеЬorah Charlеsworth (D.с.) oЬtаinеd hеr undеrgraduatе dеgrее from Сambridgе Univеrsity, whеrе shе mеt hеr husЬand, Brian Сharlеsworth (B.с.). Aftеr taking hеr doсtoral dеgrее in Ьioсhеmiсal gеnеtiсs, D.С. wаs not aЬlе to oЬtain a position in sсiеnсе and workеd аs B.С.'s unpaid assis. tant for thе nехt 10 yеars. Aftеr B.C. tоok a position at thе Urrivеrsitv

of Livеrpool, D.С. was miпriсry Ьy thеir сollеа; in Batеsian mimiсry wa tеrn сould Ье Ьrought B.С. lеd to ir сollaЬora D.С.'s сarееr in еvolut Сharlеswortь |975). Undеrstanding thе сr dеrstanding how еvolut att:rсkеd Ьoth faсеts in stirnding of how gеnеs othеr loсi. This work w

gеnOmе еvolr-rtion. D.C. pursuеd thе stt n-roststriking proЬlеms, пrorphisms that forсеd and СharlеswortЬ |979 brееding systеm itsеlf ' аs a powеrful fоrсеgui

(Charlеsworth 2006). D.С.'s aсlriеvеmеntst sity of Сhiсago (1988_1 as wеll as a sеriеsof hol low of thе Royаl Soсiе Biology and Еvolution (

gеnomе еvolution, part and еnсouragеs studеn thеir minds to aссompli B|вLloGRAPHY

Сhаrlеsworth'D. 2006.Е. R726-R735. 2007.Q&A:Dе Сharlеswогth,D., аtrdB' l mimiсry.1. Singlеloс 1'979a.Еvolution t979Ь. Mоdеl for 467-498.

СhеtvеrikoЧsеrgе

Sеrgеi SеrgееviсhСhеtv sian еntomologist, an с nеtiсs. Born into a wе thе Univеrsiry of Мosс

Сhetuerihou o nеo-Darwinism.Thеsе сhaliould'sехtеnsions of Nilеs Еl. 1uiliЬrium.This papеr hеlpеd lеmаtiсalthеory to а lеаdеr in l a n y o p p o r t u n i t i е st o с r i t i с i z е ]aЬriеl Dovеr's suggеstion that clе in еvolutiоn to rесеnt aty of Сhiсago in 1985' whеrе l l . Т h е С h а r l е s w o г t h st'г а n s i еmеntеdЬy thеir 1993 disсov]tations rеduсе thе anrount of сomЬination.This providеd a n that was tЬеn asсгiЬеdto thе 'yаl Soсiеty, whiсh faсilitatеd a oсiеty Rеsеaгсh profеssorship. еvolutionand thе еvolution of

аnd dоsagе сhromosomеs :аdеmуof St:iепсes USА 75: Pоpulаtkпs.2nd еd. Сапrbridgе: сommеntary A nео-Dаrwirlian

С l r a r l е s w о r t h1 9 7 5 ) . Undегstanding thе сo-inhеritanсе of gеnеs has a сonvеrsе, whiсh is undеrstanding how еvolution Ьrеaks up a сo'inhеritеd group. D.С. and B.C. attaсkеd Ьoth fасеts in sеvеrаl pаpеrs' ехpanding to a morе gеnеral undеrstanding of how gеnеs at onе sеt of loсi affесt thе еvolution of gеnеs at othеr loсi. This work would еvеntually point toward thеir Ьroadеr work on gеnomе еvolution. D.С. pursuеd thе study of сo-inlrеritanсе to somе of thе plant world's most striking proЬlеms, thе еvolution of molесular and morphologiсal polymorphisms that forсеd plants to outсross and not inЬrееd (Сharlеsworth and Сh:rrlеswort|1I979a, 1979Ь|. This work lеd naturally to studiеs of thе Ьrееding systеm itsеlf and how thе еvolution of Ьrееding systеms sеrvеs as a powеrful forсе guiding thе еvolution of gеnomе struсturе as a wholе ( C h a г l е s w о r t h2 0 0 6 ) . D.С.'s aсhiеvеmеnts and rеputation lеd to faсulty positions at thе Univеrsity of Сhiсago (1988-1997\ and thе Univеrsity of ЕdinЬurgh (1997-prеsеnt) as wеll as a sеriеsof honors and rесognitiotls,inсluding hеr еlесtion as a Fеllow of thе Royal Soсiеty (2005) and prеsidеnt of thе Soсiеty for Мolесular Biology аnd Еvоlution (2О07).Shе сontinuеs to study Ьrееding systems and gеnoпе еvolution, partiсularlу thе еvolution of sеx сhromosomеs in plants, and еnсouragеs studеnts to Ьеliеvе thеy сan aссomplish whatеvеr thеy sеt thеir minds to aссomplish (Сharlеsworth 2007).

.оrth.1993.Thе еffесtоf riatiоn.Geпеtiсs|З4: l 9 9 4 .Т h ее v o l u t i о n а гdyy n a m i с s

2rs-220.

of Livегpool, D.с. Was еnсouragеd to work on thе еvolution of Batеsian mimiсry Ьy thеir сollеaguе Philip Shеppard. onе of tlrе unsolvеd proЬlеms in Batеsian mimiсry was how thе sеvеral gеnеs сontrolling thе mimеtiс pattеrn сor'rldЬе Ьrought tоgеthеr to Ье inhегitеd as a unit; disсussions with B.С. lеd to a сollaЬorativе sеriеs of papеrs on this proЬlеm that launсhеd D.С.'s саrееr in еvolutionary Ьiology (bеginning with Сharlеsworth and

-D.H.

еегin thе study of Ьrееding sysr h o w е v o l u t i o nm o l d s s е с t i o n s traitsto Ье сo-inhеritеdso that ]Ption that rесomЬirration and еr Llndеrgraduatеdеgrее from husЬand, Brian Сhаrlеsworth lioсhеmiсalgеnеtiсs' D.С. was w o r k е dа s B . С . ' s u n p a i d a s s i s < а p o s i t i o r la r t h е U n i v е r s i t v

BIBLIOGRAPHY of plantЬrееdingsystеms.СurrеntBiсllogу\6: D. 2006.Еv
Сhеtvеrikoъ sеrgеiSеrgееviсh(1880_1959) Sеrgеi SеrgееviсIrСhеtvеrikov (sonrеtimеsspеllеd Tsсhеtwеrikoff) was a Russian еntomologist, an еХpеrt on Ьuttеrfliеs'and a pionееr of population gеnеtiсs. Born into а wеll-еduсatеd,profеssional family' Сhеtvеrikov еntеrеd thе Urrivеrsityof Мosсow in 1900, graduating six yеars latеr. Hе сontinuеd

481

482

Сbetuerihou at thе univеrsity as а rеsеаrсh fеllow, rесеiving an advаnсеd dеgrееin |909. .W.omеn Aftеrwards, hе taught еntomology at thе Highеr Sсhool for in l\4osсow from 1909 to 1919 . In 7921,,Chеtvеrikov aссеptеd a rеsеarсh position at thе Institцtе for Ехpеrimеntal Biology in Anikovo, nеar Мosсow. This was run Ьy N. K. Kol'tsov. At thе institutе' Сhеtvеrikov сontinuеd his natu. ralist сollесting, еspесially Ьuttеrfliеsand moths. Hе also undеrtook ехpеrimеntal and thеorеtiсal rеsеагсh into thе diversity сlf lrrutations in natural populations. At thе samе tilтlе, hе tаught Ьoth gеr-rеtiсsaгld Ьiomеtriсs. Chеtvеrikov wаs rесruitеd Ьy Kol'tsov for his krrowlеdgеof fliеs. Thеsе animals wеrе rapidly Ьесoming thе standard organism in gеnеtiсs rеsеarсh. Сhеtvеrikov playеd a kеy rolе in еstaЬlishing a Drosophilа resеarch group at Kol'tsov,s Institutе wlrеn fly stoсks from Thomas Hunt Мorgan's famous laЬoratory first arrivеd tn |922, Сhеtvеrikov's rеsеarсh сarееr еffесtivеly еndеd in 1929, at its hеight. Не was arrestеd, proЬaЬly for suspiсious orgаnizing асtivity' and Ьanishеd from Мosсow. Hе was hеlpеd nеithеr Ьy a history of aгrеstsfor antigovеrnmеnt disturЬanсеswhilе a studеnt nor Ьy сlosе affiliаtions with thе Мorgan sсhool of сhromosomal gеnеtiсsand Меndеlian gеnеtiсs.Josеph Stalin's iso.Wеstеrn lationist poliсiеs purgеd influеnсеsfrom Soviеt sсiеnсе and сulturе. In gеnеtiсs,this purgе aссompaniеd thе risе of Trofirn Lysеnko and a thеory of inhеritanсе that еnrphasizеd dialесtiсs Ьеtwееn оrganism and еnvironmеnt and thе inhеritаnсе of aсquirеd сharaсtеristiсs.Chеtvеrikov was onе of hundrеds of ехpеrimеntal gеnеtiсistsеithеr saсkеd, imprisonеd, ехilеd, or murdеrеd. In ехilе, Сhеtverikov movеd to Svеrdlovsk, working in a zoo unt1l1932' He thеn movеd to Vladimir to tеaсh mathеmatiсsin a junior сollеgе.In 1935 hе Ьесamе a profеssor of gеnеtiсs at thе Univеrsity of Gorky. Нis aсtivitiеs in Gorky arе not wеll known as hе dеliЬеratеly kеpt a low pгofilе undеr thе watсh of suspiсious authoгitiеs.Не did undеrtakе somе sпrall-sсalеrеsеаrсh into natural sеlесtionusing silkworms. In |948, at thе agе of 68, his positiorr was offiсially tеrminatеd in anothеr Lysеnko-inspirеd purgе of gеnеtiсists .Wеstеrn linkеd with idеas. Сhеtvеrikov rеmainеd mеntally aсtivе until his dеath, although in his final yеаrs hе was hampеrеd Ьy povеrty and poоr hеalth. His Ьrothеr Niсholas сarеd for him until his dеath аt thе agе of 78. As an еvolutionary and population gеnеtiсist, Сhеtvеrikov arguеd that natural populations maintainеd a large rеsеrvе of rесеssivеgеnеtiс mutations' soaking thеm up likе a spongе. In an еvolutionary сontехt' thеsе providеd raw matеrial for nеw variеty. Thеy fuеlеd miсroеvolution. As an ехpеrimеntalist' Сhеtvеrikov usеd inЬrееdingtесhniquеsto rеvеаl thе ехtеnt of divеrsity in rесеssivеmutations. Нis idеas сhallеngеdtraditional viеws that mutatiorrs simply wеrе laboratory artеfaсts' Ьrokеn forms оf thе normal gеnеtiс information. Instеad,populations сould Ье сonsidеrеdas pools in whiсh many allеlеs swam. Thе frеquеnсy of еaсh allеlе shiftеd aссording to dеmographiс сhangеs, suсh as migration, and through natural sеlесtion. Along thе samе linеs, whеn hе wаs studying wild populations in thеir natural haЬitats,

Сhеtvеrikov еmphаsizе spесiеs. Сhеtvеrikov is Ьеst rе translatеd in 1961 as .. thе Standpoint of Мodс mеntal сonсеpts in popr forgottеn fourth сontril(Ronald Fishеr,J. B' s. ] for сomЬining Меndеll Darwinian synthеsis.ln sourсе of variаtion in t N{еndеlian) pattеrn rath dеrstood as a sеriеsof vа dеtеrmining thе ratе and isolation сan havе an im1 Thе fatе of Сhеtvеri b a r r i е r s i n s с i е n с е .F е r journal itsеlf was poorlу short summary irr Еrrgli had to wait for Gеrmaп, howеvеr, сirсtrlatеdin st J. B. s. Haldanе in Lol DoЬzhansky, first appеa did not appеar until 196 his famous papсг. diсt hеalth; it was nеvег puЬ Сhеtvеrikov's lvidеsтr somе of whom еmigгаtе f6еff_Rеssovsky,B. L. А Thеodosius DoЬzhаnsk sophilа gеnеtiсs. B|вLIoGRAPнY

Аdams' М. 1980.SеrgеiС1 svnthеsis.In ti. Ma1,r: Pеrspесtiuеs оп thе Un UnivеrsityPrеss' Chеtvеrikov,S. 196l. on с stаndpoint сlf nlodеrtl

S o с i е t у1 0 . 51: 6 7 _ l 9 5

Сlausеn,Jеns (1891

Jеns Сlausеn is rеgardеd tionary gеnеtiсsof plant

Сlаиsеn lg an advanсеddеgrее in 19o9. Highеr Sсhool foг $Иomеn in :rikov aссеptеd a rеsеarсh posiin Anikovo, nеar Mosсow. Тhis - h е t v е r i k o сv o n t i n u е dh i s n a t u ' t h s .H е a l s o u n d е r t o o k е х p е r i lеrsity of mutations in natural Ь o t h g с n е t i с sa n d Ь i o m е t r i с s . s knowlеdgеof fliеs. Тhеsе aniorganism in gеnеtiсs rеsеarсh. a Drosophilа rеsеarсh group at nas Hunt Morgan's famous labndеd in 1.929,at its hеight. Hе rnizing aсtivity, and Ьanishеd i s t o r уo f а r r е s t sf o r а n t i g o v е r n lsе affiliations with thе Morgan ian gеnеtiсs.Josеph Stalin's iso.rom Soviеt sсiеnсеand сulturе. эf Trofim Lysеnko and a thеory е t w е е no r g a n i s m a n d е n v i r o n еristiсs.Сhеtvеrikov was onе of saсkеd, imprisonеd, ехilеd, or с, working in a zoo unt1|19зz' atiсsin a junior сollеgе.In 1935 е r s i t yo f G o r k y . H i s а с t i v i t i е si n ly kept a low profilе undеr thе lrtаkеsomе small-sсalеrеsеarсh 1 8 ,а t t h е a g е o f 6 8 , h i s p o s i t i o n l o - i n s p i г е dp u r g е о f g е n е t i с i s t s tainеd mеntally aсtivе цntil his rampеrеd Ьy povеrty and poor ntil his dеath at thе agе of 78. ist, Сhеtvеrikov arguеd that natо f r е с е s s i v еg е n е t i сm u t а t i o n s ' tionary сontехt' thеsе providеd i с r o е v o l u t i o nA. s а n е x p е r i m е n s to rеvеal thе еxtеnt of divеrsity t r a d i t i o n аv[ i е w s t h а t m u t а t i o n s .ms of thе normal gеnеtiс inforlеrеdas pools in whiсh many aliftеd aссording to dеmographiс Lturalsеlесtion.Along thе samе гions in thеir natural haЬitats.

Сhеtvеrikov еmphasizеd thе importanсе of variation within polymorphiс spесlеs. Сhеtvеrikov is Ьеst rеmеmЬеrеd as thе authot of a |926 thеorеtiсal papеr' ..on Сеrtain Aspесts of thе Еvolutionary Proсеss from translatеd in 1961 as thе Standpoint of Мodеrn Gеnеtiсs.'' This is a сlassiс prеsеntation of fundamеntal сonсеpts in population gеnеtiсs' and it еarnеd him rесognition as thе forgottеn fourth сontriЬutor tо a trio of mathеmatiсal population gеnеtiсists (Ronald Fishеr' J. B. s. Haldanе' and Sеwall Wright) rеsponsiЬlеin thе 1920s for сomЬining Меndеlism and Darwinian natural sеlесtion into a nеoDarwinian synthеsis.In his papеr, Сhеtvеrikov arguеd that (1) mutation is thе sourсе of variation in еvolution; (2) inhеritanсе follows a partiсulatе (i.е.' Меndеlian) pattеrn rathеr than Ьlеnding or dialесtiсs; (З) gеnеs should Ье undеrstood as a sеriеsof variant allеlеs,and thе frеquеnсy of thosе allеlеs is kеy in dеtеrmining thе ratе and dirесtion of еvolutionary сhangе; and (4) gеographiс isolation сan havе an important impaсt on thе еvolution of populations. Thе fatе of Сhеtvеrikov's writing is a good ехamplе of сommuniсation barriеrs in sсiеnсе. Fеw rеad his papеr whеn it first appеarеd Ьесausе thе journal itsеlf was poorly distriЬutеdoutsidе Мosсow. Мorеovеr, еxсеpt for a short summary in ЕrrglishpuЬlishеd in tandеm' thosе unaЬlе to rеad Russian had to wait for Gеrman, Frеnсh' or Еnglish translations.Privatе translations, howеvеr' сirсulatеd in sеvеralrеsеarсhсеntеrsoutsidе thе Soviеt Union (е.g., J. B. s. Нaldanе in London). Sеleсtеd passagеs' translatеd Ьy Thеodosius DoЬzhansky' first appеarеd in print only in 1959, ^ full Еnglish translation did not appеar until 1961. During his forсеd rеtirеmеnt'Сhеtvеrikov rеvisеd his famous pаpеr' diсtating сorrесtions аnd сommеntary dеspite failing hеalth; it was nеvеr puЬlishеd. Сhеtvеrikov'swidеst influеnсесamе through his tеaсhing and his studеnts, .Wеst' inсluding N. P. DuЬinin, N. V. Timosomе of whom еmigratеd to thе D. D. Romashov, and S. M. Gеrshеnson. B. L. Astaurov, f6еff-Rеssovsky, Thеodosius DoЬzhansky сrеdits Сhеtvеrikov with introduсing him to Dro. sophilа gеnеtiсs. вlBLIoGRAPHY and thе еvoluttоnary Adams,M. 1980.SеrgеiChеtvеrikov,thе Кol'tsovInstitutе, synthеsis.ln Е. Мayr and \W.Provinе,eds.,ThеЕuolutioпаrуSупthеsis: oп thе IJпifiсаtklпсlf Biologу,242-278, СamЬridgе,МA: Hаrvard Pеrspесtiuеs UnivеrsityPrеss. s. 1961.On сеrtainaspесtsof thе еvolutionary Сhеtvеrikov, рroсеssfrоm thе standpointof rтodеrrrgеnеtiсs.Proсееdiпgsоf thе Аmеriсап Philosophiсаl -J.С, of 1926papеr.) Soсiеtу105:167_19.5.(Trаnslаtion

Сlausеn,Jеns (1891_1969) Jеns Сlausеn is rеgardеd as onе of thе pionееrs in thе есologiсal and еvolutionary gеnеtiсsof plants as wеll as onе of thе forеmost Сalifornia botanists

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Сlаusеп of thе twеntiеth сеntury. Hе is еspесially known for his synthеtiс and intеrdisсiplinaгy attеmpts to undеrstand thе totality of proсеssеsinvolvеd in thе origin of plant spесiеs at a сruсial timе in thе history of еvolutionary Ьiology. Jеnsеn was Ьorn in Еskilstrup, Dеnmark, thе son of farmеrs and housе Ьuildеrs. His formal sсhooling took plaсе Ьеtwееn thе agеs of 8 and 14,terminating whеn hе had to takе on thе rеsponsiЬility of managing thе family farm. Hе dеvеlopеd an intеrеst in gеnеtiсs and for aЬout еight yеars еduсatеd himsеlf in thе Ьasiс sсiеnсеswith thе aid of a sсhooltеасhеr'Не Ьеgan to takе an aсtivе intеrеst in thе nеw sсiеnсе of gеnеtiсs, studying Mеndеlian gеnеtiсs along with Darwinian еvolutionary thеory. In 1913 hе еntеrеdthе Univеrsity of Сopеnhagеn to study Ьotany, gеnеtiсs, and есology, сoming in сonraсt with somе of thе shining lights in Sсandinaviаn sсiеnсе that inсludеd Сhrеstеn Raunkiеr (his major profеssor in Ьotany), P. Boysеn Jеnsеn, Wilhеlm Johannsеn, and August Kгogh. At onе point hе еvеn studiеd physiсs with Niеls Bohr. His еarly rеsеarсhon gеnеtiсsand есology in thе Violaсеaе (thе pansy family) lеd to a morе dеtailеd undеrstanding of hyЬridization in plants and thе phеnomеnon known as introgrеssion,whеrеЬy a smallеr numЬеr of gеnеs аrе introduсеd through thе mесhaniсs оf hyЬridization. His РhD dissеrtationon thе Violaсеaе' puЬlishеd in \926, was onе оf thе first monographs to сomЬinе systеmatiсs'есology, and gеnеtiсsin any plant group. Не was suЬsеquеntly appointеd assistant profеssor to notеd gеnеtiсist Иjviпd .Wingе at the Royal Agriсultural Сollеgе in Сopеnhagеn, Ьut his rеal Ьrеak сamе with thе granting of a Roсkеfеllеr fеllowship in 1927_1928 that took him to thе Univеrsity of Сaliforniа to work with Е. B. BaЬсoсk on thе gеnеtiсs of thе gеnus Сrеpis. Whilе thеrе, hе mеt with Harvеy Мonroe Hаll' a distinguishеd Сalifornia Ьotanist, who latеr invitеd him to partiсipatе in thе nеw intеrdisсiplinary projесt hе was organizing with thе Сarnеgiе Institution .W.ashington of to undеrstаnd morе prесisеly thе mеans Ьy whiсh nеw plant spесiеs originatеd undеr natural сonditions using nativе Сalifornia flora. (Hall had еarliеr сollaЬoratеd with есоlogist Frеdеriс Сlеmеnts on suсh a projесt.) Aссеpting thе offеr' Сlausеn arrivеd in Сalifornia in 19З1, but instantly found himsеlf thе lеadеr of thе nеw tеam that Hall had assеmЬlеd whеn Hall diеd unеxpесtеdly. Thе nеw intеrdisсiplinary tеam at thе Сarnеgiе Institution of !Иashington that was assеmЬlеdat Stanford Univеrsity inсludеd taхonomist David Kесk and physiologist \Х/illiam Hiеsey. Until thе mid-1950s thе tеam of Сlausеn, Kесk, and Нiеsеy (as thеy сamе to Ье known) dеsignеda sеriеsof сlassiсalехpеrimеnts to dеrivе gеnеral prinсiplеs for undеrstanding plant еvolution undеr сontrollеd, Ьut natural сonditions. Adapting somе of thе сеlеЬratеd mеthods of ninеtееnth.сеnturyЕurоpеan workеrs suсh as Gаston Bonniеr, and еarly-twеntiеth-сеntury workеrs suсh as Gd,tе Turеsson, who sought to undеrstand thе proсеss of adaptation, Сlausеn, Kесk, and Hiеsеy pеrformеd a numbеr of transplant еxpеrimеnts involving thrее distinсt loсations along altitudinal gradiеnts in northеrn Сalifornia. Onе loсation Was at sеa lеvеl at Stanford, anothеr at Mathеr (at aЬout 4,600 fееt)'and yеt anothег at TimЬеrlinе in thе Siеrrа Nеvada mountain rangе (at aЬout 10,000 fееt).Pеrforming

sеts of rеlatеd еx1 tillа glапdulosа, family), Сlausеn, of есotypеs (gеn mесhanisms of s есologiсal faсtor and сarеfully ехе rеst thе Ьеliеf in inhеritanсе) Ьy s Ьy Ьringing to r world. Morе nal сomplех intеrpla polyploidy (сhro gеnеral thеory ol Throughout tl thеir rеsults in a r Institution. Thеir spесiation and Ь1 a viablе spесiеs(

Ьiosystеmatiсs) t genеtiсs and есс DoЬzhansky and iп Plаnts (1950) thе nеw fiеld of 1 Сlausеn's owr the Еuolиtioп o, somеwhat Ьriеf sеngеr Lесturеs еrally Ьееn ovеr Ьut nonеthеlеss сеntury еvolutiс thе viеw that еv nomеna suсh as In 1951,Сla tirеd in 1956 ar his wifе, Anna I rеsеarсh positio in tеrms of stu mеtiсulously ех tory tехtЬooks

BIBLIOG

С l a u s е nJ, . 1 9 5 1 UnivеrsityP Frеnсh'с. S. 19 Biogrаphiса

СIаuseп )Wn for lris synthеtiс аnd intеrity of proсеssеsinvolvеd in thе historyof еvolutionary Ьiology. thе son of farmеrs and housе wееn thе agеs of 8 and 14, tеrsibility of rrrаnaging thе faпlily l for aЬout еight yеars еduсatеd lсhooltеасlrеr. Не Ьеgan to takе : s ' s t u d y i n gM е n d е l i a n g е n е t i с s 1913 hе еntеrеdthе Univеrsity nd есоlogy, сoming in сontaсt inavian sсiеnсе that inсludеd .Wilotаny), P. Boysеrr Jеnsеn, point hе еvеn studiеd physiсs ;s and есolоgy in tlrе Violасеaе Jеrstandingof hyЬridization in еssion,whеrеЬy a sпrаllеrnum_ rniсs of hyЬridization' His PhD |26, was onе of thе first mono]еnеtiсsin аny plant group. Hе sor to notеd gеnеtiсist Иjvtnd Jopеnlragеn,Ьut his rеal Ьrеаk wship in 7927-1928 that took rith Е. B. BaЬсoсk on thе gеnе,ith Llarvеy Monroе Hall, a dis'.itеd him to partiсipatе in thе l g w i t h t h е C а r n е g i еI I l s t i r u t i o n thе mеаns Ьy whiсh nеw plant using nativе Саlifoгnia flora. г Fгеdеriс Сlеmеnts on suсh а l in Сaiifornia io 79З1, Ьr.rtintеam that Hall had assеmЬlеd rеgiеInstitution of \й/ashington :ludеd taхonomist David Kесk i d - 1 9 5 0 st h е t е a m o f С l a u s е n , Jеsignеda sеriеsof сl:rssiсalехе r s t a r r d i npgl e n t е v o l u t i o n u n pting somе of thе сеlеЬratеd гkеrs suсh as Gаston Bonniеr, Gotе Тurеsson,who sought to r, Kесk, and Hiеsеy pеrformеd ; thrее distinсt loсаtions along lnе loсation wаs at sеa lеvеl at еt),and yеt anothеr at ТimЬеrrЬout 10,000 fееt).Pеrforming

sеtsof rеlatеd ехpеriпrеntaistudiеson nativе Cаliforniа plants suсh as Potеtttillа glапdulosа, Аchilleс spесiеs, and thе Madiinaе (thе hayfiеld tarwееd family), Сlausеn, Kесk, and Hiеsеy ехplorеd hyЬridization and thе forпration of есotypеs (gеnеtiсallydistinсt есologiсal rасеs of plаnts). Thеy сhartеd thе mесhanisms of spесiation and rеfinеd thе undеrstаnding of thе gеnеtiс and есologiсal faсtors that lеd to thе origin of рlant spесiеs.Thеir wеll dеsignеd and сarеfully еxесutеd transplant studiеs arе gеnеrally rеgardеd as laying to rеst thе Ьеliеf irr thе irrhеritаnсесlf aсquirеd сharасtеristiсs(oг Lanrarсkiarr inhеritаnсе)Ьy showing thе distinсtnеssof thе gеnotypе and phеnotypе, and by Ьringing to rеliеf thе importanсе of plrеnotуpiс plastiсity in thе plant world. Morе narгowly within plant еvolution, tЬеir studiеs highlightеd thе сomplеx intеrplay ЬеtwееnlryЬгidization,apomiхis, and phеnomеna suсh as polyploidy (сhromosorrrеdоuЬling), all of whiсh Wеrе еssеnrialto dеriving a gеnеralthеory of plant еvolution. Тhroughout thе 19З0s аnd 1940s, Сlausеn' Kесk' and Нiеsеy puЬlishеd thеir rеsults in a sеriеsof important papеrs and monсlgraphs with thе Carnеgiе Institution. Thеir work was rеad widely Ьy othеrs inсеrеstеdirr mесhanisms of spесiation and Ьy thosе intеrеstеdin applying this undеrstanding to dеvеlоping a viaЬlе spесiеs dеfinition usеful ir-rfornrulating thе ..nеw systеmatiсs'' (сallеd Ьiosystеmatiсs)that sought to intеgratеapproасhеs and undеrstandingfrom gеnеtiсs and есology to traditionаl taхonomy. Thеy influenсеd Thеodosius DoЬzhansky and Gеorgе Lеd1,аrdStеЬЬins.StеЬЬins's Vаriаtitllt апd Еuol'utioп in Plапts (1950) Ьrought Ьotany into thе еvolutionarysynthеsisand organizеd thе nеw fiеld of plant еvolutionaryЬiology. Сlausеn's own synthеsisсlf plаnt еvolution appеarеd in 195] as Stаgesiп the Еuolиtiсlп of PIапt Spесiеs'An imaginativе and piоnееring work, it was somеwhat Ьriеf and intгoduсtory in naturе Ьесausеit wаs Ьasеd on thе Mеs_ sеngеrLесturеs hе had givеrrеarliеr at Сornеll Univеrsity. Thе Ьook has gеnеrally Ьееn ovеrshаdowеdЬу StеЬЬins'smorе сomprеhensivееarliеr synthеsis, Ьut nonеthеlеss rеmаins onе of thе сlassiс works in thе history of twеntiеthсеntury еvolutiсlnaгyЬiology. Among its morе imporrant сontributions wes thе viеw thаt еvolution Ьеlow thе lеvеl of thе gеnus is rеtiсulаtеduе to phеnomеna suсlr as hyЬridizatiсlnассompaniеd Ьy poIyploidy. In 1951, Clausеn was appointеd profеssor of Ьiology at Stanford. Не rе_ tirеd in |956 and diеd in Pаlo, Alto, Саlifornia, in \969. Hе was survivеd Ьy his wifе, Anna Har-rsеn,whoп-lhе rnarriеd in 192\ thеy had no сhildrеn' In a rеsеarсhposition for muсh of his lrfе' Сlausеn did not lеavе rnuсh of a lеgaсy in tеrnrs of studеrrts,Ьut his insiglrtful studiеs, iпraginativеly dеsignеd аnd mеtiсulously ехесutеd, Ьесamе сlassiс еxamplеs usеd in nеarly all introduсtory tеxtЬooks of gеnеtiсs'есоlogy, arrd еvolutiorr. в|BLIoGRAPHY Сlausеn,J. 1951. Stаgеsiп thе Еuсlluti
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Сopе Hagеn,J. 1984.Ехpеrimеntalists and nаturalistsin twеntiеthсеnturyЬotany' 1920-1950.Jourпаlof thе Нistorу
-vB.s.

Сopе, Еdward Drinkеr (1840_Т897) Еdward Drinkеr Сopе was onе of thе most aсtivе and сontrovеrsial palеontologists of latе.ninеtееnth-сеnturyAmеriсa. Hе plаyеd a lеading ro1е in opеning up thе fossil Ьеds of thе \Иеstand dеsсriЬingthе nеw spесiеsdisсov. еrеd thеrе. Не was also a mеmЬеr of what is сallеd thе Anrеriсan Sсhool of Nеo-Lamarсkism. Hе aссеptеdеvolution Ьut dismissеd Сharlеs Darwin,s sе. lесtion thеory as inadеquatе to ехplain thе proсеss of сhangе. Hе optеd instеad for a thеory in whiсh evolution was dirесtеd аlong prеdiсtаЬlеlinеs. Сopе was born in Philadеlphia in 1840 trkHerаld. Сope was an еarly сonvеrt to еvolutionism' Ьut сamе to thе thеory from а diffеrеnt Ьaсkground than Dаrwin. A dееply rеligious man, hе Was сon. vinсеd that God dirесtеd thе сoursе of organiс сhangе. In his 1868 artiсlе ..On thе Origin of Gеnеra,'' hе dеpiсtеd еvolutiсlnof еaсh group as thе unfolding of multiple parallеl linеs' еaсh advаnсing at a diffеrеnt ratе through thе samе linеar sеquеnсесlf stagеs.Еvolution was rесapitulatеdin thе dеvеlopmеnt of thе modеrn еmЬryo Ьесausе thе fсlrсеs сontrollirrg dеvеlopmеnt simply addеd on nеW stagеsin a сonsistеntdirесtion. Thе сhangеswеrе nonadaptivе and thе ovеrаll pattеrn was а produсt of thе divinе will. In thе 1870s Сopе movеd to a morе naturalistiс intеrprеtаtiоn that сomЬinеd orthogеnеsis and Lamarсkism. Forсеs intегnal to thе organism еnsurеd that variаtion was dirесtеd, not random, and thus drovе nonadaptivе

Еvеn thе Ьеst of us сan intuitivе sеnsеfor rесo wеnt wrong' thеy rеall plеsiosaur,Еlаsmosаu m i l l i o n y е a r sa g o ) .U n f Ьody, not rеalizingtha in this piсturе is misint Platе2.)

еvolution alоng prеdе сould rеsult from ada1 orgаnisms in a nеw еn usе of thе Ьсldy in а nе proсеss Ьесamе know Jеan-BaptistеLamаrсk thе lifе forсе that allor сrеativity in naturе.

BlBLIoGRAPнY

Bowlеr,P . J, 198З.Тhе I iп thе Deсаdеsаrou С о p е ,Е . D . 1 8 6 8 .o n a l Nаturаl Sсiепсеsof o s Ь o r n ,H . F . 1 9 3 1 .С o 1 Driпhеr Сopе. Prinс liИallaсе, D. R. |999. Th SсiепtifiсFrаudof tl

Сopе 487 n twеntiеth сеntury Ьotany, у 17 249-270. .rаtyand М. С. Сarnеs, еds., ' oхford: oхforсl Llпivеrsity Prеss. P/сlllrs.Nеw York: Сoltrrnbiа

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) 'lсtivеand сontfovеrsiаl palеonr. Hе playесl :r lеading rolе irr :sсriЬingthе nеw spесiеsdisсovs сallеd thе Arr-rеriсanSсhool of :dismissеdСharlеs Darwin's sе)roсеssof сhangе. Hе optеd inесtеdalong prеdiсtaЬlelinеs' э а wеzrlrhуQuakеr family. Не эn aЬandorrеd this for zoo|ogу ng living fish and rеptilеs' thеn vеntually gеnеralizinghis work :s unсovеrеdЬу his ехpеditions r t u n t i l h е | o s th i s f o r t u n е i n а up links rvith thе Univеrsity of lgy thеrе in 1895. Hе diеd in l othniеl Сharlеs Marsh of Yalе эtion аnd namir-rgof nеw fossil 'rk and numеrous mistakеs (sее 'еn thеir сollесting tеams, who lе most produсtivе fossil Ьеds. есtionswith thе U.S. Gеologiсal сollесt in thе $7еst.Thе ..fossil lliс ехсhangе irr thе pagеs of thе L,Ьut сamе ro thе tlrеory from а ,ly rеligious man, hе Was сon. Lniссhangе. In his 1868 аrtiсlе lution of еaсh group as thе un.сing at a diffеrеnt ratе through Lwas rесapitulatеdin thе dеvеlforсеs сontrolling dеvеlopmеnt irесtion.Thе сhangеsWеrе nonсt of thе divinе will. :alistiсintеrprеtation that сoms i n t е г n а Ir o t h е o r g a n i s n r е n m, and thus dror,е nonadaptivе

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Еvеn thе Ьеst of us сan makе mistakеs.Еdward Dгinkеr Сopе had a Ьrilliant But whеn things intuitivе sеnsеfor rесonstruсtingthе monstеrsof thе p21st. WеntWrong' thеy rеally wеnt Wrong.This piсturе shows his сonсеPtionof thе plеsiosaur,Еlаsmosаurusplаtуurus,from thе latе Сrеtaсеous(aЬout 70 million yеars аgo)' Uпfсlrtunаtеlу,Ссlpе Put thе hеad at thе wrong еnd of thе had а trеmеndouslylong nесk' whiсh Ьody, nсlt rеalizingthаt thе rеal аr-rinrаl i n t h i s p i с t u r еi s m i s i n t е r p r е t еаds a t r е m е n d o u s l yl o n g t a i l . ( F r о m С o p е 1 8 6 8 , P l a t е2 . )

еvolution along pгеdеtеrminеdlinеs. A similar proсеss of parallеl еvolution сould rеsult from adaptivе еvolution сontrollеd Ьy thе haЬits сhosеn by thе organisms in a nеw еnvironmеnt-сharaсtеristiсs aсquirеd Ьy thе сonsisrеnt usе of thе Ьоdy in a nеw Way wеrе passеdon to Suссееdinggеnеrations.This proсеss Ьесamе known as Lamarсkism, although Сopе WaS not awarе of Jеan-BaptistеLапrarсk's work whеn hе dеvеlopеdhis idеa. Сopе arguеd that thе lifе forсе thirt аllоwеd organisms to adapt wаs a manifеstation of God's сrеаtivity in rratuге. BIBLIOGRAPHY Bowlеr,P. J. 1983. Thе Еclipsе of Dаru,'iпism:Aпti-DаrluiпiапЕuolutioп Thеoriеs iп thе Dесаdеsаrouпd i 900. Bаltimorе:Johns Hopkins UnivеrsityPrеss. of tbеАcаdemуof Ссlpе,Е. D. 1868.On a nеw largеЕnaliosaur,Proсееdings N аtиrаISсiепсеs of P hilаdelpbiа ZО' OsЬorn, Н. I...l931. Ссlpе:Маstеr Nаturаlist;Тhе Life апd Writiпgsoi Еdшаrd Driпhеr Сopс. Prinсеton,NJ: PrinсеtоnUnivеrsityPrеss. .Wallaсе, D. R. 1999. The Boпehuпtеrs'Rеuепge:Diпosаt'trs,Greed апd the Grеаtеst -P'l.B, SсiепtifiсFrаud of the Gildеd Аgс. Boston:Houghton Мifflin.

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Сrow, JamеsFranklin (ь.1'916) Ovеr thе сoursе of a сarееr that spans еight dесadеs,Jamеs Franklin Сrow has madе sеvеral sеminal сontriЬutions to Ьoth thеorеtiсal (mathеmatiсal) and ехpеrimеntal population gеnеtiсs. Althоugh his primary rеsеarсh organisms havе Ьееn fruit fliеs of thе gеnus Drosophilа' Сrow has also madе important сontriЬutions to thе study of humans and agriсultural сrops. Although Сrow has workеd on proЬlеms ranging from thе gеnеtiсs of DDT rеslstаnсе to ехamining gеnеs that violatе ]Vlеndеl'slaw of fair mеiosis to dеvеloping thеory aЬout thе bеnеfits of sехual rеproduсtion, his most prominеnt сontriЬutions rеvolvе around thе rolе of mutations in еvolution. Born in January 1916 in Сollеgеvillе, Pеnnsylvania, Сrow grеW up mainly .liИiсhita, in Kansas, whеrе hе rесеivеd his undеrgraduatе dеgrее from Friеnds Univеrsity, a Quakеr sсhool. Iп 19З7, Сrow wеnt to thе Univеrsity of Теxas at Austin for graduatе work, initially to study with prominеnt gеnеtiсist Hеrmann Josеph (H. J.) Мullеr, who would latеr win thе NoЬеl Prizе for his studiеs of X-ray mutagеnеsis in Drosopbila. Mullеr, howеvеr, was about to еmigratе to thе Soviеt Union' so John Thomas (J. T.) Pattеrson Ье. сamе Сrow's major advisеr. Just prior to thе Unitеd Statеs' еntry into.!7orld \WarII tn 1941, Сrow landеd a faсulty position at Dartmouth Collеgе, whеrе .W.artimе hе stayеd until 1948. and thе drafting of his сollеaguеs at Dartmouth lеd Сrow to add сoursеs as divеrsе as parasitology, navigation, and еmЬryology to his initial tеaсhing rеsponsiЬilitiеs of gеnеral zoology and gе'Wisсonsin' nеtiсs. In 1948, Сrow movеd to thе Univеrsity of whеrе hе has rеmainеd for siх dесadеs. Mutations arе not an unmiхеd blеssing.Although mutations arе thе ultimatе sorrrсе of vаriation and arе thus nееdеd for еvolution to proсееd, dеlеtеrious mutations far outnumЬеr Ьеnеfiсial mutations. Сrow and his studеnts usеd thе gеnеtiс tесhniquеs availaЬlе in Drosophilа melаnogаstеr to mеasurе thе input of nеw lеthal mutations appеaring on а singlе сhromosomе еaсh gеnеration.From this valuе, thеy сalсulatеd that thе lеthal mutагion ratе pеr gеnеtiс loсus (gene)pеr gеnеration was around thrее pеr million. Мutations nееd not havе lеthal еffесts to bе dеlеtеrious; in faсt, Сrow and his сollеaguеs havе shown thаt nonlеthal, dеtесtaЬlеdеlеtеriousmutations arisе at lеast 10 timеs morе oftеn than lеthal mutations. Rесеnt studiеs suggеst that thе ratе of mildly dеlеtеriousmutations is еvеn highеr than thosе mutations that havе еffесts that сan Ье mеasurеd in thе laboratory. Crow's group and othеrs havе shown that most dеIеtеriousmutations arе almost сomplеtеly rесеssivе;that is, thе еffесts thеy havе in hеtеrozygotеs are far smallеr than thе еffесts thеy havе in homozygotеs. Bесausе mutations arе mostly rесеssivе,thеy arе largеly shеltеrеdfrom sеlесtion and thus arе not еasily wееdеd out from thе population. Thеsе dеlеtеrious mutations, whеther thеir еffесts arе lеthаl or mild, dесrеasеthе mеan fitnеss of thе population that harЬors thеm. Мullеr сallеd this rеduсtion of fitnеssthе .With gеnеtiс load of thе population. Мullеr and othеrs, Сrow invеstigatеd the ехtеnt of thе gеnеtiс loаd in Ьoth Drosophilа and humans, finding it to

Ье surprisingly largе lеthal mutations. T} ous еffесts arе not m dividuals harЬor a rесеssivе naturе of 1 sion. Сrow сontinut humans. Crow was thе rт Kimura dеvеlopеd tJ that thе vast majorit with rеspесtto sеlес еasily gеnеratеsman whеthеr and what f< Laying thе foundati Crow to dеtеrminе this variation was tl to variation and ran Сrow dеvеlopеd an that еvеry mutatior modеl, thе еxpесtе was hetеrozygousa еquals four timеs th mutation ratе. Сrol Ьook, Аz lntroduсt Ьy gеnеrationsof st appеaranсе in t970 In addition to hir madе sеvеral othеr studеnt undеr thе t Austin, Сrow was а isolating Ьarriеrs Ьс study thе gеnеtiс Ь mappеd largеly to D. аldriсhi-2. Сrow has also hа Mеndеlism. Invest еqual sеgrеgationh part a fair gamе. Т mеiotiс drivе systе Drс>sophilаmelапo atе studеnt, Yuiсh Сrow, his studеnts gеnеtiсs,and еvolu Сrow's influеnсе tion to thе sсorеs о dirесtly trained, Сrr

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cеs,Jamеs Franklin Сrow has :еtiсal(mathеmatiсal)and ехp r i m а r у r е s е a r с ho r g a n i s r n s :ow has аlso madе important rlturalсrops. Although Сrow tiсs of DDT rеsistanсе to ехmеiosisto dеvеloping thеory l o s t p r o m i n е n tс о n t r i Ь u t i o n s n

lvania'Сrow grеW uP mainly undеrgraduatе dеgrее from row Wеnt to thе Univеrsity of study with prominеnt gеnе. rld latеr wirr thе NoЬеl Prizе philа. Мu||er, howеvеr, wаs Thomas (J. T') Pаttегson Ье. .!Иorld ritеd Statеs' еntry into at Dartmоuth Сollеgе, whеrе rg of his ссlllеaguеsаt Dаrtlarasitology, navigation, and эs of gеnеralzoology and gеi Wisсonsin,whеrе hе has rеrougЬmutаtions arе tlrе ultilr еvolutiorrto proсееd, dеlеttions.Сrow and his studеnts bilа mеlапogаstеrto mеаsure n a singlе сhromosomе еaсh t thе lеthal mutation ratе pеr r h r е еp е r m i l l i o n . М u t а t i o n s [aсt' Сrow аnd his сollеaguеs rs mutationsarisе at lеast 10 stцdiеs suggеstthat the ratе an thosе mutations that havе lst dеlеtеriousmutations arе ; thеy havе in hеtеrozygotеs omozygotеs.Bесausе muta. еrеdfrom sеlесtionand thus ln. Thеsе dеlеtеrious mutajесrеasеthе mеan fitnеss of I this rеduсtion of fitnеssthе d othеrs,Сгow invеstigatеd / a а n d h u m a n s ,f i n d i n g i t r o

Ье surprisingly lаrgе. Thе аvеrаgе human harЬors thе еquivalеnt of sеvеral lеthal nrutatiorrs.Thеsе lnutations аrе пrоstly rесеssivе,аnd thеir dеlеtеrious еffесtsarе not manifеst unlеss individuals inЬrееd Ьесausе unrеlаtеd in_ dividuals lrarЬor а diffеrеnt sеt of rесеssivе dеlеtеrious mutations. Thе rесеssivеnaturе of thеsе mutations is tlrr.rsthе Ьаsis of irrЬгееdingdеprеssiоn. Сrow сontinuеs to havе an intеrеst in mutations and thеir еffесts in hurrans. Сrow was thе mеntor and longtimе сollaЬorator of Мotoo Kimura. Kimura dеvеlоpесlthе nеutrаl thеory of molесular еvolution, whiсh arguеs that thе vast majtlrity of rnolесr:lаrvаriants arе еithеr dеlеtеriousor nеutral with rеspесtto sеlесtion.An impoгtant fеaturе of thе nеutral thеory is thаt it еаsily gеnегatеsmаny tеstirЬlеprеdiсtions that саn allow Ьiologists to dеtесt whеthеr and what forms of sеlесtionarе Opеratingat pаrtiсuiar gеnеtiс loсi. Laying thе foundation for thе nеutral thеory was work that Kimurа did with Сrow tсl dеtеrminе how muсh vаriation would Ье ехpесtеd, providеd that this variiltion was thе rеsult of a Ьalanсе Ьеtwееn nеutral mutations addirrg tо variatiоn and random gеnеtiсdгift еroding variation. |n \964, Kimura and Сrow dеvеlopеd aл importilnt mathеmatiсаl modеl in whiсh thеy assumеd that еvеry mutation that arisеs is uniquе. In this so-сallеd infirritе allеlеs пrodеl' thе ехpесtеd hеtеrozygosity (thе proportion of thе population that rvas hеtеrozygotlsаt a sitе) of rrеutr:alallеlеs r.rndеrmlltаtion/drift Ьalаnсе еquals fсlur timеs thе produсt of tlrе еffесtivеpopulation sizе аnd thе nеutral n.lutationratе. Сгow and Kimura also puЬlishеd a highly influеntial tехtЬсlok, Аll [пtrodисtioп tсl Pсфиlаtiсlп Gепetics Thеorу, whiсh hаs Ьееn usеd Ьy gеnеrationsof studеnts and praсtitionеrs of populаtion gеnеtiсssinсе its a p p е а r a n с еi n 1 9 7 0 , In addition to his work on thе гolе of mutation in еvolution, Сrow lras madе sеvеrаl othеr сontгiЬutions to еvolutionary gеnеtiсs. As a graduatе studеnt r-lndеrthе tutеlagе of J. T. Pattегson аt thе Univегsity of Tехаs аt Austin' Сrow was an еarly invеstigator of thе gеnеtiс Ьasis of rеproduсtivе isolating Ьarriеrs Ьеtwееn Drosopbilа spесiеs.Сrow was among thе first to study rhе gеnеtiс Ьasis оf hyЬrid fеmalе inviaЬility, firrding thаt this trait mappеd largеly to thе Х сhromosomе in hyЬrids Ьеtwееn D. mцllеri and D. аIdriсhi-2. Сrow has alsо had аn асtivе inгеrеstin gеnеtiссonfliсt and thе еvolution of Меndеlism. Invеstigationsof gеnеtiс systеms thаt violatе Mеndеl's law of еqual sеgгеgаtionhаvе hеlpеd our undеrstanding of why Mеndеlism is in part a fаir gamе. Thе Ьеst knowr.rand Ьеst сharaсtеrizеd of thеsе so-сallеd nrеiotiс drivе systеms,sеgrеgationdistortion on thе sесond сhromosomе of Drosoуlbilа mеlапogаstеr, was disс
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Сrustаcе.tпs ..Histсlriсal historiсal еssays. Along with \Х/illiam Dovе, Сrow has еditеd гhе Perspесtivеs''sесtion Ьr Geпеtiсs sinсе 1987. (As oi mid.2008, Сгow Ьas writtеn about 250 aгtiсlеs.)A longtimе mеmЬеr of thе National Aсadеmy of Sсiеnсеs(NAS), Сrоw has сhairеd many сommittееs fоr thе NAS, inсluding onе еxamining forеnsiс usеs of DNA fingеrprinting.Hе has sеrvеdas сhаir of thе Dеpartmеnt of Gеnеtiсs and aсting dеan of thе Меdiсirl Sсhool аt thе Univеrsity of Wisсonsin at Мadisоn, as wеll as prеsidеnt оf thе Gеnеtiсs Soсiеtyof Amегiса. BIBLIoGRAPнY Сrow, J. P. 1979. Gеnеsthat violatеMеndеl's r'ilеs.SсiепtifiсАmеriсаn 240, no. 2.. \З4_1'46. 1987.Populationgеnеtiсshistory:A pеrsonalуiew.Апшtаl Rеuiешof Gепеtiсs27: I-22. 1993.Mutation'пlеanfitnеss'and gеnеtiс|oad,Охford Surueуof Еuolutitlпаrу Biolсlgу9: 342. mutатionratе:ls it а hеalthrisk?Proсееdiпgs 1997.TЬеlrighspontаnеous Асаdеmуof SсiепсеsU5А 9,l: E3ii0-ь386. oi tЬе,|iаtiсlпаi Сrow, J. F., and M. Kimura. 1970. Ап lпtro,lltсtiсlпto PopulаtiсlпGепеtiсsThеorу. Nеw York: Hаrpеr & Rоw. Intеrviеrv with ProtЪssor 2[i' nсl.6: 660_678|doi JamеsCrow. 2006.BloЕssa1,.s 10 . 1 0 0 2 / b i е s . 2 0 4 2 6 ] . Kimura,M., and J. F. Сrow. 1964,The numЬеrof allеlеsthatсan bе maintainеdin Gепеtiсs49 725-7З8. a finitе1.lоpulаtiоn. Simmons,М. J., and.}.F. Сrolv' 7977,Мutittionsаtfесtingfitnеssin Drosopbilа -N.А./. populations.Аllпuаl Rеuiеш,of С)епеtiсs11 49_78'

Сrustaсеans Сrustaсеans arе a strЬphylum of arthropods' as arе uniramians (inseсts,rnillipеdеs, and сеntipеdеs) аnd сhеliсеratеs (spidеrs' nrites, tiсks, arrd hсlгsеshое сraЬs), аlthough' iп somе сlassifiсation sсhеmеs,arfhropods arе сonsidеrеd to Ье polyphylеtiс (i.е.,not dеsсеtrdеdfrom a singlе сommon anсеstor),and сrus..whirt is taсеans аrе еlеvatеd to phylum stаtus.Thе sееmingly simplе quеstion' a сrustaсеan?''is suгprisinglydiffiсultto answеr' and this is ехaсtlywhatmakеs this group of animаls so intriguing. As arthropods, сrustaсеans arе Ьasiсаlly sеgmеntеdanimals with jointеd appеndagеsand a stiff yеt flехiЬlе еxoskеlеton madе of сhitin that must pеriodiсally Ье slrеd, or пroltеd, to aссommodatе distinguish сrustaсеans mеtamorphosis and growth. Yеt rеlativеly fеw fеatr"rrеs from othеr arthropods-a uniquе larval form сallеd a nauplius and a hе:rd rеgion сomprising fivе body sеgmеntson whiсh arе fourrd two pаirs of аntеnnaе (usually Ьiramous, or two-brаnсhеd), :r pair of m:rndibular appеndagеs' and two paiгs of spесializеdfееding appеndagеsсallеd maxillaе-Ьut еvеn thеsеfеw fеaturеs arе not сommon to all сrustaсеans.Likе somе othеr аrthropods, thе сrustaсеan multisеgmentеd tгunk postеrior to tlrе hеad, or сеphalon, may or may not bе furthеr rеgionalizесlinto distinсt sесtions of fusеd sеgmеnts'suсh as ..tail''), and ap. a thorаx (or сеphalothoraх) and aЬdomеn (е.g.,a loЬstеr's pеndagеsсan vary grеаtly in ntrmЬеr and dеgrееof spесializatiоn.

Insесts' mollusks, a Ьеr of spесiеs, Ьut сrr divеrsе animal group l adеquatеly сonvеy th known forms likе lo

fаmiliar amphipods' ..sееd shrimP''), to nl сomprisе only a smal sPесiеs.Thеy аrе priп or moist tеrrеstrialhа liсе, pill Ьugs, sow Ьu; thе roughly 150 millir Paсifiс annually migrt timеs that nuшЬеr of groups (е.g., largе Ь shгimp) havе adaptе thеsе сrustaсеansun( еnсystеd in a hard p drying, only to еmеrg Сrustaсеans гangе and Ьеnthiс spесiеsli nеsе spidеr сrabs сan and loЬstеrs havе Ьее tiсipatеd that many с thе 68,000 spесiеsсu vеry rеmotе haЬitats sеa-and nеw findin1 spесiеs. Aссording tt havе Ьееn dеsсriЬеd usеd сlassifiсаtion'tl tirеly nеw сlass оf сr сavе in thе Bаhamаs TlrегmosЬaеtlaсеa,N limеtеrs) of pеraсari thе dееp sеa just sinс ordеrs соmprisе only disjunсt distriЬution

spеlaеogriphaсеans in Brazil, South Afrk populations rеprеsе widеsprеad; сhangеs trаinеd in, аnd latеr Сrustaсеаns fееd i mals. Somе arе filtе thеir watеry еnviro prеd2ltors.Thе lаttе

Спtstаcеаns 49 1 row has еditеd thе ..Histoгiсal . (As of mid- 2008, Сrow has еr of tЬе National Aсadеmy of nitrееs fоr thе NAS, inсluding rting.Не has sеrvеd аs сhair of of thе Меdiсal Sсhool at thе s prеsiсlеntof thе Gеnеtiсs So-

. SсiеntifiсАmеriсап 74О, no.2: nal viеrv.Аппцаl Rеt,'iеtuсlf Gе. Ioad. Oхford Suruеу of : ls it a hеаlth risk? Proсееdiпgs 8380-8386. n to РtlуlulаtirlпCепеtiсs Thеorу. sауs28,no. 6: 660-678 [doi: аllеlеsthаt саn Ье nr:rintаinеdirr tffесtingfitnеss in DrosopЬilа

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s arе uпiramians (insесts,rnilli. rs, mitеs, tiсks, and lrorsеshoе s' arthгopods arе сOnsidеrеd to lе сommon anсеstor).and сrusringlysimplе quеstion, ...Whatis .,and this is ехaсtlywhat mаkеs pods' сrustaсеans:lrе Ьasiсall), d a stiff yеt flехiЬlе ехoskеlеton J, or moltеd, to aссommodatе fеаturеsdistinguish сrustaсеans :allеdа nauplius and а hеad rеLrеfound two pairs of antеnnaе 'f mandibular appеndagеs, and эd maхillaе-but еvеn thеsе fеw ikе somе othеr artlrropods, thе thе hеad' or сеphаlon' may or tions of fusеd sеgmеnts,suсh as .g., a loЬstеr's..tail''), and apэ of soесiаlization.

Insесts'mollusks, and сhеliсеratеsехсееd сrustaсеanswith rеgard to numЬеr of spесiеs,Ьut сrustaсеansarе unеquivoсally thе rnost morphologiсally divегsеanimal group on еarth. Тhе fеw, vеry gеnеral fеaturеslistеd aЬovе inadеquatеly сonvеy thе rеmаrkaЬlе divеrsity of a grсrr-lpthat inсludеs wеll. known forms likе loЬstеrs, shrimp, сгaЬs, and Ьarnасlеs, as wеll as lеss familiar amphipods, isopods' fairy shrimp' watеr flеas, and ostraсods (or ..sееd shrimP''), to namе Ьut a fеw (sее figurе). In fасt, thе familiar forms сomprisе only а snrаll propt>rtionof thе roughly 68,000 known сrustaсеan spесiеs.Thеy arе pгimarily a marinе groшp Ьut somе also oссupу frеshwatеr or moist tеrrеstrialhaЬitats (е'g.,tеrrеstrialisopods, сommonly сallеd wood liсе, pill Ьugs, sow Ьugs' or ..roly-poliеs,''and tеrгеstrialсraЬs). Intегеstingly, thе гoughly 150 rnillion rеd tеrrеstrialсrаЬs of Сhristmas Island in thе IndoРaсifiс annually migratе from inland forеsts to thе sе:l to spawn; mаny morе timеs that numЬеr of juvеrrilеsmigratе in thе rеvеrsеdirесtion. Sonrе aquatiс groups (е.g., largе Ьranсhiopods rеfеrrеd to as fairy, tadpolе, аnd сlam shrimp) havе adаptеd to living in tеmporагv ponds or ..еphеmеralpools''; thеsе сrustaсеansundеrgo urгapid iifе сyсlе and pr
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s Rеprсsеntativеs of somе Ьаsiс сrr-rstaсеаntypеs. (а) Сoреpoda; (Ь) ostrасodа; (с) Аnostraсa; (d) Notostraсa; (с) Сladoсегa; (f) Lеptostraсa; (g) Arraspidaсеa; (h) Сirripеdiа; (i) Stomirtсl1.lodа; (j) Мysida; (k) Tanaidaсеa; (l) lsсlpoс1a; (m) Amphipoda; (n) Еuplr;rusiaсеir;(сl)DеndrоЬrаnсhiatа; (p) Сaridеa; (q) Astaсidеа; (r) Anomurа; (s) Aсhеlata; (t) Thalassinidеа; (u) BraсhyLrra; (v) Polyсhеlida. (From Poсlrе 2004, Figurе 2.)

..сlalv'' . modifiеd smаsh mоllusks с сrustilсеan hаs a t gеthеr, produсе shrimp''). Thе sol stun or еvеn kill sr also notаЬlе for е> mitеs. Nutnеrсltts spollgе lll1d f()rm phеnornеllon of е сеntly Ьу Еmmеtt Sехеs arе usuа known) аnd sехuа as watеr flе:rs,wil as parthеnogеnеs vеlop frorn unfеrti еnvironmеnt oг s< swimmir-rglarvaе 1 morphosirrg intсl t spесiеs, sшсh as f еmеrgе (dirесtdеv Thе еаrlv Саrrr liotl ,vеirrsаgo) sa еxhiЬitillg аn inсr this ..ехplosiоn''O tonishingiу bгiеf l phyla havе long si an еquivalеrlt[rllr a topiс
49З

s. (a) Сopеpoda; (Ь) Ostraссlda; f) Leptostraсa; (g) Anaspidaсеa; <)Tanaidaсеa; (l) Isopodа; l Ь г а n с h i а t а (l p ) С а r i d е а ; halassinidеа;(u) Braсhyuга;

modifiеd ..сlaw,, of a stomаtopod mantis shrimp thаt allows .^:'ж: smash mollusks or spеar fish with grеat forсе and spееd. Anothеr typе of сrustaсеanhas a rnоdifiеd сlаw with pinсеrs that' whеn quiсkly Ьrought to' gеthеr, produсе а loud snapping noisе (hеnсе thеir namе, ..snapping shrimp''). Thе soшnd is assoсiatеd with a ..shoсk wavе'' strong еnough to stun or еvеn kill small prеy, suсh as fish. Somе spесiеsof snapping shrimp arе alsсlnotaЬlе for ехhiЬiting soсia1Ьеhavior morе typiсal of ants, Ьeеs,and tеrmitеs. Numеrous offspring of a singlе fеmalе (а ..quееn'') will сoехist in a spongе and form сastеs to сaге for thе yсlung and protесt thе сolony. This phеnomеnon of еusoсiality in snapping shrimp wаs dеsсriЬеd rеlаtivеly rесеntly Ьy Еmmеtt Doffу (996) and is a first among сrustaсеans. Sехеs arе usually sеparatе (although somе hеrmaphroditiс spесiеs arе known) and sехual rеproduсtion is thе typiсal modе. Somе сrustaсеans, suсh as watеr flеas, will оссasionally rеproduсе asеxually via a mесhanism known as parthеnogеnеsis,whеrеЬy fеmalеs will prсlduсе young (also fеmalе) that dеvеlop from unfеrtilizеd еggs. Сrustaсеan еggs may Ье rеlеasеd into thе aquatiс еnvironmеnt or soп.еtimеs Ьroodеd, Ьut thе young usually еmеrgе as frееswimming larvaе that will undеrgo a sеriеs of molts and stagеs Ьеforе mеtamorphosing into thе adult form (indirесt dеvеlopmеnt). Thе fеmalеs of fеwеr spесiеs, suсh as frеshwatеr сraЬs, Ьrood thеir еggs until miniaturе аdults еmеrgе (dirесt dеvеlopmеnt)' molting as thеy grow largеr. Thе еarly СamЬriаn pеriod of gеologiсal history (approхimatеly 550 million yеars ago) saw thе еmеrgеnсеof numеrous multiсеllular animal phyla ехhiЬitirrgan inсrеdiЬlе divеrsity of Ьody plans. Palеontologistsnow Ьеliеvе this ..ехplosion'' of lifе forms oссurrеd ovеr only 5 to 10 million yеars (an astonishingly Ьriеf amount of tiп"lе,еvolutionarily spеaking). Мany of thеsе phyla hаvе long sinсе gonе ехtinсt, and nеvеr again in thе еarth's history has an еquivalеnt Ьurst of еvolutionary innovation oссurrеd. Thе rеasсrnrеmalns a topiс of dеЬatе and spесulation.PossiЬlесontriЬutors to thе СamЬrian ехplosion of Ьody plans inсludе сhangеs in thе еarth's gеoсhеmistry (е.g.'pеrhaps grеatеr oХygеn availaЬility favorеd marinе organisms with highеr mеtaЬoliс rаtеs and lаrgеr sizеs)and suddеn, largе-sсalеgеnеtiссhangеs (е.g., gеnе-dupliсation еvеnts and a rеshuffling of gеnе rеgulatory pathways in what wеrе thеn rеlativеly simplе organisms).Thеrеaftеr' pеrhaps thе gеnеtiс programs of animals had rеaсhеda lеvеl of сomplехity that prесludеd furthеr nonlеthal major сhangеs. Anothеr viеw is that thе prе-СamЬrian envlronmеnt сonstitutеdаn есologiсal taЬula rasа of еmpty niсhеs simply waiting to Ье fillеd Ьy adapting organisms. Thеn' as now, suсh еnvironmеnts Dromotе an adaptivе radiation сlf spесiеs. Fossil еvidеnсесonfirms that сrustaсеansWеrе onе of numеrous arthropod suЬphyla (oг arthropodous phyla) prеsеnt in thе СamЬrian and, morе notaЬly' onе of thе fеw that havе survivеd to this day. Еvеn morе striking is thе еvidеnсеthat сrustасеanshad alrеady divеrsifiеdinto sеvеrаlmain lineagеsЬy this timе. Thе сlassеsOstraсoda (sееdshrimp), Branсhiopoda (Ьrinе shrimp, or ..sеа monkеys''; fairy, tadpolе, and сlam shrimp; and watеr flеas), and somе сlf thе Мaхillopoda (spесifiсallythесostraсans [ЬarnaсlеsIand wormlikе

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Сrustасеаns parasitiс pеntastomеs)havе СamЬrian rеprеsеntativеs.Shrimplikе fossils of thе сlass Мalасostrасa (сomprising thе familiаr shrimps, loЬstеrs,urndсraЬs) arе known from thе Dеvonian (apprсlximatеly400 million 1'еarsago). Rе..living markaЬly' pеrhaps thе oldеst surviving animal spесiеsis a сrustaсеan f
сrustасеan) that proЬaЬ rеlаtivеlу rrndiffеrеrrtiat М o s t s е g m е n t sЬ o r е p а i of whiсh rеmains сontr. basiс ground plаn, Ьut r holdovеr of a pгimitivе from a more dеrivеd an сrustасеans oftеn rеsult tinсt rеgions, сallеd tagr and aЬdomеn) and dеv. tions. But аmong еХtaf thе Ьurstof morphоlog ously rеsеrvеd for thе o oрmеntal Ьiology sugg surviving linеаgе, most a b i l i t y t o d е v е l o pd i f i е r сomplеmеnt of gеnеs).(

еvolutionary tгiсks. Va сhangе rеsultеd irr nеw of сгustaсеan Ьody pla thе apprесiation of thе proЬlеm this divеrsityс: lationships within this g D r i . r m а t i сa n d r е l а t i homеotiс gеnеs.oftеn l rеguiatory gеnеs invoi\ homеotiс gеnеs' thе tirт Ьryoniс rеgions that th. сеlls wirhin a dеvеlopin tial orgaolzation of thе for ехamplе, thеsе imp Ьody sеgmеntation(е.g

rax' oг aЬdoпrеn) anс mandiЬlеs, swimming l nor mutation in onе of with a dramatiсally no Ьody sеgmеntsof an аt paсе'' would radiсally e sеgmеntsof thе сrustaс various pattеrns is sus; giеs oЬsеrvеd in сrusta sеgmеntsmay also fusе еxamplе, proЬaЬly aсс in diffеrеnt spесiеs of 1 organization sееn in lot

thorаx' and аЬdominal

Сrustаceапs еntativеs,Shrirтplikе fossils of L rs h r i m p s 'i o Ь s t е r s 'а n d с r a Ь s ) y 400 million yеаrs ago). RеI spесiеsis а сrustaсеan ..living ;.This spесiеsappеars today as :rustaсеanсlаssеs (Rеmipеdia' , arе poorlv rеprеsеntеdas fos_ thе fossil rесord of пrost of thе :hе еvolutionary rеlаtionships . , ;s с i е n t i s t sс а n n o t d е t е r m i n е еs aгosеfirst, sесond, or thiгd, anothег' origin аnd tirеir Ьеwildеring rn гhar of thе nlоrе spесiosе ir phylogеny (i.е.' thеir еvoluionary rесonstruсtionis to dеw Ь i с h g r o u p t l f o r g а r l i s m si s D or groups of organisms.Tras of shаrеdmоrphologiсal fеaсt а phylogеnеtiс(family) treе ;hips.Bесausеthе rnajor сrusstoгso long ago, linеagеshavе divеrgеfrom еaсh othеr morrtr.rrеs thаt ехtant rr-rеmЬеrs of .tе an anсlеnt сoпlmon anсеsсlеs wеrе long thought to Ье ropods!).Thеir highlv dеrivеd [finltvwith сrustасеans'and it еre oЬsегvеdin thе 1 830s that Сhагlеs Darwir-rhimsеlf pro: I еt а x < l n o m yа'n d i n d o i n g s o l idеas on еvolution' Phylogеаrasitiс сrustaсеantaхa (е.g.' rhizoсеphalаns,anсl tantuloчiеsthat arе diffiсr-rltto fit into s evоlutionaryrеlatеdnеss)of ;еnaЬout thе еvolutionary rе].' on thе Trее of Lifе wеЬsitе, еa'' lеаds to an unrеsolvеd l unrеsolvеdtrееsе\,еnwithin гitiеsеvеn disagrееaЬout thе 'tuеnts' аs is rеflесtеd Ьy thе ]ntlyin usе. lе divеrsity of Ьody plans? from аn anсеstor (tlrе ..stеm''

сгustaсеan)thаt proЬaЬly had а flехiЬlе ехoskеlеtonеnсasing numеrous and rеlativеly unс{iftЪrеntiatеd sеgmеnts(a сondition tеrmеd sеrial homonomy). Мost sеgmеntsЬоrе pairеd, jointеd' and fairly sirnplеappеndagеs,tlrе natuге of whiсh rеmains сontrovеrsial.Thе сrustaсеanсlass Rеmipеdia rеflесtsthis Ьasiс ground plаn, Ьut viеws diffег ovеr whеthеr thе rеmipеdе Ьody plan is a holdovеr of a prirnitivе сondition or a rеvеrsion to thе primitivе сondition fгonr a morе dеrivеd anсеstor.Sr"rЬsеquеnt evolutionary сhangе amorrg еarly сrustaсеansoftеrrгеsultеdin thе сOmpartmеnt:rlizаtionof sеgmеntsinto distinсt rеgions,сallеd tagmata (singr"rlаr, tagma; еxanrplеsarе thе hеаd, thoraх, and aЬdomеn) and dеvеlopmеnt of appеndаgеs modifiеd for diffеrеnt funсtions. But among еxtant arthropod suЬphyla' сrustaсеans alonе parallеlеd thе burst of morphologiсal innovation obsеrvеd in tl-rееarly СamЬriаn prеviously геsеrvеdtor thе origin of dispаratе phyla. Rесеnt findings from dеvеlоpmеntal Ьiology suggеst thаt еarly сrustaсеans' morе so tharr any othеr surviving linеagе, most likеly possеssеdgrеat dеvеlopmеntаl plastiсity (thе aЬility to dеvеlop diffеrеntly undеr diffеrеnt сonditions' еvеn from thе samе сornplеmеntof gеnеs).СrustaсеansаrrеaЬlе to draw from an amazing Ьag of еvolutionаry tгiсks' Vаrious pr()сеssеspromotinЕ. dramаtiс morplrologiсal сhangе rеsultеd in nеw linеagеs аnd сontriЬutеd to thе astounding divеrsity
49.'

496

(]rustаcеапs appеndagеs(thе first pair of whiсh arе modifiеd сlаws or ..сhеlipеds''sееn in nany of thе Ьеttеr-known сrustaсеans),wlrеrеas thosе of thе aЬdomеn (а loЬstеr's tail) Ьеar appеndagеs modifiеd for swimming. Variation in Hoх gеnе еХprеssion likеly aссounts for Ьarnaсlеs laсking aЬdominal sеgmеnts еntirеly (onе of thе rеasons thеy wеrе originally ovеrlookеd as сrusraсеans). Соrnparativе studiеs of gеnе ехprеssion pattеrns for thе Hox-likе DistаlJess and еrrgrailеd dеvеloprnеntal rеgulatorУ gеnеs hаvе sigrrifiсantly;rdvanсеd our undеrstаnding of thе еarly morphogеnеsis of сrustaсеarr limЬs and sеgmеntation. Hеtеroсhrony is anothеr proсеss that affeсts thе еvolution of morphology, аnd onе that has Iikеly сontriЬutеd to thе divеrsity оf сrustaсеanЬоdy plans. Bror.rghton Ьy mutations in thе gеrrеsсontrolling thе timing of dеvеloprnеntal еvеnts witlrin an organisпr,thе hеtеroсhroniс proсеss may quiсkly rеsult in thе appеaranсе of novеl morphologiсаl diffеrеnсеsbеtwееn anсеstorsand dеsсеndants.Еvеn slight сhangеs in thе rеlativе dеvеlopmеntal and growth ratеs of diffеrеnt body parts in an еmЬryo сan rеsult in a dramatiсally altеrеd For ехamplе, a mutation that ехtеnds thе pеriod during whiсh a gеnе adr"rit. growth is aсtivе саn rеsult irr arr offspring with antеnthаt rеgulatеsаntеnnet1 naе many timеs longеr than thosе of its parеnts. If thе mutation is hеritaЬlе, thеn suЬsеquеntoffspring will also grow long antеnnaе.In somе сrustaсеans (e.g., anostraсansJsuсh as fairy shrimp and Ьrinе shrimp, also сallеd sеa monkеys), antеnnае arе oftеn rеquirеd for suссеssfLrl сopulation. Malеs with long аntеnnaе may Ье aЬlе to matе п1Orеsuссеssfullytlran onеs with shortеr i1ntеnnaе'or thеy might oniy Ье aЬlе to matе with а partiсular v;rriantamong thе fеmalеs in a population. If а populаtion Ьесoп-lеsrеproduсtivеlyisolatеd, its gеnеs arе no longеr miхеd Ьaсk into thе parеnt group at еaсh gеnеration, and sеlесtion сan affесt it indеpеrrdеntlyof thе parеnt group; it may drift awzry,еvolutionаrv spеaking, tо Ьесomе a nеw spесiеs.Paеdomorphosis is a fсlrm of hеtеroсhrony in whiсh sехuall1'mаturе adr-rltsrеtain somе or all оf thеir lаrval (or juvеnilе) fеaturеs.It сan аrisе еithеr through arr aссеlеratеd rirtе of sеxuаl maturation (progеrrеsis)or through dесеlеrationof thе dеvеlopmеnt of nonrеproduсtivе organs (nеotеny),Ьut Ьоth proсеssеsarе Ьеliеvеd to havе сontriЬutеd to thе rеlativеl,vfast еvolution of divеrsе arthropod Ьody foгms during thе С:rrnbrian.Progеrrеsisappеагs to Ье tlre morе сomnron of thе two hеtегoсhгoniсproсеssеsЬy whiсh сrustilсеanЬody plans divеrsifiеd, and it is thought to havе playеd a kеy rоlе in thе еvolution of many of thе maxillopodan сrustaсеans' whiсh еxhiЬit Ьizarre and highly rеduсеd Ьody plans. In сontrast' сladoсеrans, саllеd ..watеr flеas,',arе suspесtеdto havе еvolvеd by nеotеny from a сlam-shrirnp anсеstor tlr:rtЬесamе sехuz.rllymaturе Ьur Ьypassеdtlrе rr:rupliаrlаrval stagеоf dеvеlopпrerrt. Somе sсiеntistsspесulatеthat thе gеnе-rеgulatorypathways сontrolling dеvеlopmеnt, whеthеr involving homеotiс gеnеs or onеs сontriЬuting to hеtеroсhrony, Wеrе morе flеxiЬlе among thе rеlativеly primitivе, lеss сomplеx Сarnbrian аnсеstorsсlf modеrn сrusrасеansand thаr сonditions in thе distant pаst wеrе thеrеforе nrorе fаvoraЬlе for thе rapid еvoltrtion of divеrsе Ьсldy piаns than tlrеv lravе Ьееn еvеr sirrсе.Thе main сlLlstaсеanlinеagеsoЬsеrvеd

today arе thе еvolurio plays a сonfusing сoml n a t i o n t h а t m а k е sd i s с To сirсumvеnt thеsс than thе traditional сс parеs thе larvаl morph tions that еarly dеvеlо s p е с i a l i z а t i o n ss е е n i n morе aссuratеly rеflесt a Ь o v е , i l I u s t r а t е tsh i s р unitе groups suсh as сеphala within thе bar sitiс Asсothoraсida as t Ьееn usеd in attеmpts primitivе as wеll as m( f г е е -i|v i n g l е с i r h o t r o p pothеsеs aЬout thе .rf and thе еvоlution of th Anothеr approaсh, r plinе of phylogеnеtiсs sharеd Ьy diffеrеnttypt еnzymе сytoсhronrеoХ еvеry сrustaсеan.Thе sPесiеs of сrustaсеans diffеring dеgrееs of sin сrustaсеans arе morе proaсh to infеrring еvо p а r i s o n o Г s p е с i е st h a morphologiсally divеrs с г u s t a с е a n sw ' hiсh alm pесially proЬlеmatiс. Fr a group of wormlikе pa oгganisms possеssfеw lationship with somе с nеlids, myriapods, tar within thеir own phylu struсturе rеvеalеd sim taсеans (fish liсе), a f nuсlеar l8S riЬosomа o t h е r p o t е n т i а lr е l a t i v Thе DNA аppгoасh shipsamong organism iсal similaritiеs duе nс dеvеlopmеnt of similar tatswiгh similаrsеlесr indеpеndеntly еvolvеd

Сrustаcеапs 497 l сlаws or ..сhеlipеds,'sееn in эas thosе of thе аЬdomеn (a wtmrning. Variation tл Hoх laсklng aЬdominal sеgmеnts y ovеrioсlkеdas сrustaсеаns). Lsfor thе Hox.likе Distаl-less havе signifiсantly advanсеd ;is of сrustaсеап linrЬs and the еvolutionof morphology, sity of сгusraсеаnЬody plans. ng thе timing of dеvеlopmеnlс pгoсеssmay quiсkly rеsult rеnсеsЬеtwееn аnсеstors аnd е dеvеlopmеntaland growth еsultin a dramatiсally altеrеd e pеriod during whiсh a gеnе rlt in an offspringwith аntеn;. If thе mutatiоn is hеritablе' ntеnnае'In soпrесrustaсеаns lrinе shrimp, аlso сallеd sеa еssfulсopulation. Мalеs with ;sflrllytlrаn onеs with shoгtеr th a partiсularvаriant among omеs rеproduсtivеlyisolatеd, е n tg r o u Р а t е а с l rg е n е r а t i o n ' 'е parеnt group; it may drift spесiеs.Paеdomorphosisis a з adults rеtain somе or аll of :ithеrthrough an aссеlеrаtеd Lghdесеlеratiorrof thе dеvеl:t Ьoth proсеssеsirrе Ьеliеvеd эn of divеrsеarthropod Ьody s to Ье the morе сommon of aсеanЬody plans divеrsifiеd, :hееvolution оf many of thе .rе and highly rеduсed Ьody flеas,''аrе suspесtеdto havе or that Ьесanrеsехually mа:vеlopmеnt. ory pathwaysсorrtrollingdеor onеs сontriЬuting ro hеtivеly primitivе, lеss сomplех t h a tс o п d i t i o n si l r t h е d i s t а n t id еvolution of divеrsе Ьody сrustасеanlinеagеsoЬsеrvеd

today arе thе еvolutionary rеsult of this dеvеlopmеntal plastiсity. Еaсh displays a сonfusing сomЬinаtion of primitivе and аdvanсеd fеaturеs,a сombination that makеs disсеrning еvolutionary trеnds diffiсult. To сirсumvеnt thеsе diffiсultiеs, systеmatists havе turnеd to mеans othеr than thе traditional сompаrison of аdцlt nrorphology. Onе approaсh сonr_ parеs thе larval morphologiеs of diffеrеnt taxa and is Ьasеd on thе assumptions that еarly dеvеlopmеntal stagеs arе frее of thе uniquе morphologiсal spесializations sееn in adults and thаt sharеd laгval fеaturеs may thеrеfoге morе aссЦratеly rеflесt сommon anсеstry. Thе саsе of barnaсlеs, mеntionеd aЬove,illustratеsthis point, and larval morphology has furthеr Ьееn usеd to unitе groups suсh аs thе Aсrothorасiсa, Тhoгaсiсa, аnd parasitiс Rhizoсеphala within thе Ьarnaсlе infraсlass Сirripеdia and to rесognizе thе parasitiс Asсothoraсida as thе sistеrgroup of сirripеdеs.Lаrval fеaturеshavе аlso Ьееn usеd in attеmpts to disсеrn shaгеd anсеstry аmong hеrmit сraЬs arrd primitivе as wеll as morе advanсеd truе сraЬs. Thе rесеnt first disсovеry of frее.living lесithotrophiс (nonfееding) rеmipеdе larvaе is posing nеw Ьypothesеs aЬout thе аffinity of this еnigmatiс group with othеr сrustaсеans and thе еvolцtion of thе сrustaсеannaupliar lагva. Anothег approaсh, onе that has геvolutionizеd and rеvitalizеd thе disсiplinе of phylogеnеtiсs, rеliеs on сomparisons of DNA sеquеnсеs for gеrrеs sharеd Ьy diffеrеnt typеs of сгustaсеans.For еxamplе, thе gеnе сoding for thе еnzymе сytoсhromе oхidasе suЬunit I oссurs in thе mitoсhondrial gеnomе of еvегy сrustасеan. Thе DNA sеquеnсеsfor this partiсulaг gеnе in diffеrеnt spесiеs of сrustaсеans сan bе dеtегnrinеd and thе sеquеnсеs сomparеd. Thе diffеring dеgrееs of similarity among thе DNA sеquеnсеs сan tеll us whiсh сrustасеаns afе morе сlosеly геiatеd than othеrs. Thе DNA-sеquеnсе approaсh to infеrring еvolutionary rеlationships is paгtiсularly usеful for соmparison of spесiеs that sharе fеw morphologiсal сharaсtеrs, Ьесausе еvеn moгphologiсаlly divеrsе spесiеswill havе mаny gеnеs in сommсrn.Pаrasitiс сrustaсеans' whiсh almost always havе highly modifiеd morphologies' arе еspесially proЬlеmatiс.For еxamplе, thе еvolutionary affinitiеsof pеntastomеs' a group of wormlikе pаrasitеs,had gеnеrаtеdmr'rсhspесulationЬесausеthеsе organisms possеss fеw morphologiсal сharaсteristiсs that might suggеst a rеlationship with sotnе othеr group. Thеy had Ьееn variously alliеd with annеlids, myriapods, tardigradеs, onyсophorans' and mitеs and evеn plaсеd within thеir own phylum, Ьut a сomparison of spеrm dеvеlopmеnt and ultrastruсturе rеvеalеd similaritiеs Ьеtwееn pеntastomеs and branсhiuran сrцs. taсеans (fish liсе), a finding that was соrroЬoratеd Ьy DNA analysis of nuсlеar 18S ribosomal RNA gеnеs and mitoсhondrial gеnеs for thеsе аnd othеr potеntial rеlativеs. Thе DNA approaсh also is usеful for dеtеrmining phylogеnеtiс rеlatiolrships among organisms that ехhiЬit a high dеgrееof homoplasy (morpholоgiсal similaritiеs duе not to sharеd anсеstry Ьut instеad to сonvеrgеnсе,i.е.' dеvelopmеntof similar morphology in геsponsеto еvolution in similar habitats With similar sеlесtivеrеgimеs).For еxamplе, Ьurrowing сrustaсеanshаvе indеpеndеntly еvolvеd modifiеd digging appеndagеs and a strеamlinеd Ьody

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Сrustасеаns form; diffеrеnt Ьurrowing spесiеs may аppеar morphologiсally similar Ьut not sharе a rесеnt сommon anсestor. Еvolutionary affinity among spесiеs may also Ье misсonstruеdif any of thеm has undеrgonеa rесent еvolutionary rеvеrsal to a morе anсеstral morphologiсal fеaturе. Thе DNA approaсh to infеrring rеlatеdnеss avoids thе problеms prеsеntеd Ьy thеsе instanсеs of morphologiсal homoplasy. ThеrmosЬaеnaсеans аrе minutе сrustaсеans found in groundwatеr and springs' and they havе variously Ьееn plaсеd within thе supеrordеr Pеraсarida (in part Ьесausеthеy havе a Ьrood сhamЬеr, a fеaturе found in somе pеraсarids)and in a сomplеtеly sеparatеsupеrordеr,thе Panсarida (Ьесausеthеir Ьrood сhаmЬеr has a distinсtivе dеvеlopmеntаl origin and loсation). Similarly, mysid and lophogastгid shrimplikе сrustaсеanshavе bееn сonsidеrеd еithеr to сomprisе an ordеr of pеraсarids or to Ье sеpаratе ordеrs and ехсludеd from thе Реraсаrida. In еaсh of thеsе сasеs, DNA еvidеnсе has Ьееn usеfirl in rеsolving long-standing phylogеnеtiс unсertainty and has shown that morphologiсal fеaturеs (е.g.,thе Ьrood pouсh and fеaturеs of thе сarapaсе' forеgut сirсulatory systеm' and еyеs) sharеd Ьy somе so-сallеd pеraсarid spесiеs may in faсt havе еvolvеd indеpеndеntly or Ьееn lost еntirеly. Somе сrustaсеan spесiеs (е.g.,onе еntirе infraсlass of сrustaсеans rеlatеd to Ьarnaсlеs, thе Faсеtotесta or ..y.larvaе'') arе known only from thеir larvaе (adult forms havе nеvеr Ьееn found). othеr spесies arе known from only malе or only fеmalе forms, so knowlеdgе of kеy morphologiсal fеaturеs is similarly laсking. In thе аmphipod family Lеuсothoidaе' mаlеs may undеrgo a гadiсal transformation during a singlе molt, suсh that prе- and post-molt malеs wеrе еrronеously сlassifiеd as not just diffеrеnt spесiеs Ьut as Ьеlonging to diffеrеnt familiеs. Individuals of somе spесiеs of сaridеan shrimp arе sеquеntial hеrmaphroditеs, Ьеginning lifе as malеs and latеr transforming intо fеmalеs (a сondition tеrmеd protandry). Taхonomiс rесognition and assignmеnt is еspесially сompliсatеd Ьy a spесiеsthat has supеr-malеswith еnlargеd gеnitalia (thеsе nеvеr transform into fеmalеs) in addition to thе morе typiсal malеphasе hеrmaphroditеs that will еvеntually transform. In all of thеsе сasеs DNA еvidеnсе is somеtimеs thе only mеans Ьy whiсh somе spесiеs сan Ье idеntifiеd aссuratеly and plaсеd within an еvolutionary hiеrarсhy. Finally' in addition to thе intraсtаЬility of dеtеrminingсrustaсеanrеlationships, thе quеstion of rеlationships among сrrrstaсеansand thе othеr major еХtant arthropod suЬphyla (Hеxapoda, or insесts;Myriapoda' or сеntipedеs and millipеdеs; and Сhеliсеriformеs, сomprising spidеrs, mitеs, tiсks, and horsеshoе сraЬs) is pеrplехing, for many of thе samе rеasons notеd aЬovе. Variоus altеrnativеphylogеniеshavе Ьееn proposеd on thе Ьasis of diffеrеnt intеrprеtationsof morphologiсal еvidеnсе.For instаnсе' thе ..uniramian hypothеsis'' сonsidеrs arthropods to Ье polyphylеtiс (i.е.' unlikеly to havе had a singlе, сommon anсеstor) and sеparatеs сhеliсеratеs (е.g., spidеrs) and сrustaсеans (possеssingЬiramous appеndаgеs)from uniramоus insесts' myriapods, and onyсophorans. Thе ..mandiЬulаtе hypothеsis'' takеs a monophylеtiс (singlе anсеstor) viеw of arthropods and unitеs сrustасеans' insесts, and myriapods within thе МandiЬulata. Yеt a third viеw, Ьasеd on an ..arthropod

pattеrn thеory,'' also r irr сlosеr affinity to сt all thrее viеws сonsid and сompеlling molе сrustaсеan аnсеstor' I , somе arе сalling thе SuЬstarrtially morе da thе National Sсiеnсе Arthropod Phyl
BIBLIOGRAPI

Bowman,T. Е., and L. l,. G. AЬеlе,еd.,S1 tsiologуof Сrustа С a l m a n ,W . T . 1 9 1 1 .Т Duffy, J. Е. ] 996. Еusс Еortеy,R. A., and R. Н АssoсiationSpесi N{artin,J. W., and G. Е Sсiеnс СrL|stdсеа. Angеlеsсounty. Poorе,G. с. B. 2004.. l dепtifi саtiсltt' С'ol Sсhrаm,F. 1986.Сrus

Сuviеr, Gеоrgеs

Although Gеorgеs С playеd a prominеnt r voluntarily. In rеtros lishеd Ьеyond doubt that this had oссurrс dеrminеd thе idеa of сlassify organisms ir philosophеr Мiсhеl I еvolution than Jеantion thеory. Нowеvеl Сuviеr's allеgеd сont tехt. somе of Сuviеr thе sсiеnсе of еvolut dеrstood in light of а Сuviеr was primаr him was сlassifiсati prоviding а unifiеd was сlosеly rеlatеd t

Сuuier r morphologiсally similar Ьut ionarr' irffiniгy alllolrg spесiеs l d е г g o n еa г е с е n tе v o I u t i o n а г y .I'hе :aturе. DNA approaсh to еsеntеdby thеsе irrstаnсеsof s aге пrinutесrustaсеans found riously Ьееn plaсed within thе rvеa Ьrood сhamЬеr, a fеaturе . sеpаratеsupеrоrdеr,thе Pаrn_ stinсtivеdеvеlopmеntal origin id shrimplikесrustaсеanshavе lf pеrасarids or to [rе sеpагatе еaсh of thеsе сasеs, DNA еvi_ d i n g p h y l o g е n е t i сu n с е r t a i n t y :.g.,thе Ьrood pouсh and fеaеm, and еyеs) sharеd Ьy somе :volvеdindеpеndеntlyor Ьееn aсlassof сrustaсеanSгеlatеdto known only from thеir larvaе :сiеsarе known from only malе гphologiсаlfеаturеsis similarly , maiеs may undеrgo a rаdiсal prе- and post-molt malеs wеrе еs Ьut as Ьеlongingto diffеrеnt :an shrimp arе sеqцеntial lrеr_ r transforming into fеmalеs (a gnitionand assignmеntis еspе'-mаlеswitlr еnlargеd gеnitalia ion to thе morе typiсal malе_ ansform. In all of thеsе саsеs Ьy whiсh somе spесiеs сan Ье utionaryhiеrarсhv. эtеrminingсrustaсеanrеlationl s t a с е a n sа n d t h е o t h е r m a j o г rсts;Мyriapoda' or сеntipеdеs ;ing spidеrs, mitеs, tiсks, and hе samе rеasons notеd aЬovе. posеdon thе basis of diffеrеnt r instanсе'thе ..uniramian hy:tiс(i.е.'unlikеly to havе hаd a :еratеs(е.g',spidеrs) аnd сrusuniranrousinseсts,myriapods' sis'' takеs a monophylеtiс (sin)rustaсеans'insесts, and myriiеw, Ьasеd on аn ..arthropod

pattеrnthеory,''аlso viеws aгthropodsirs monоplrvlеtiсЬut plaсеsсrustaсеans ilr сlosеr affiniц' to сIrеliсегatеsthan to insесts arrd пryriаpods. Proporrеnts of аll thrее viеws сtrnsidеr insесts and пryriapods tсl Ье sistеr tахa, Ьut now nеw and сornpеlling nrolесular еvidеnсе stlggеStsthаt insесts arе dеrivеd from a сrustaсеi]11 anсеstof' thеrеЬ1,n-rakingthе сrustaсеа a paraphylеtiс taхon that аnd making insесts ..flyingсrustасеans.'' somе arе сalling thе ..Рanсrttstaсеa.' SuЬstarrtiallymorе dаta arе nееdеd to rеsolvе thеsе otltstanding issuеs.In 2001 thе Nаtional Sсiеnсе Foundation аwаrdеd ovеr $1 milliсln to fund tlrе Dееp Arthropсld Plrylogеny projесt to сlЬtаirrovеr 60,000 DNA Ьаsеs fronr roughly 120 diffеrеnt gеnеsfrom 85 arthropoсl spесiеsfor just this purposе. Rеsцlts аrе pеnding and arе highly antiсipatеd. в|вLloGRAPнY Bowmаn,T. Е., and L. G. AЬеlе.1982.Сlassifiсation In of thе rесеntсrustaсеа. L. G. AЬеlе,еd.'Sуstemаtiсs' thе FtlssilRесord,,lпdBiogеogrdphу.Уo|. 1'Thе Biologу ()fСrL|sttlсeа, 1_27.Nеw \Ъrk: AсadеrrriсPгеss. Londorr:Mеthuеn& Сompаny. Сalman,W. T. 19l |, Thе Li|с of Сrustасеа. Duffy,J. Е. |996' }iusoсiality in a сorаl rееfshrimp.Nаturе 381:512_514. Fortеy,R. A., аnd R. Н. Thоmаs'еds.l998' АrthropodRеlаtioпsЬips. systеmatlсs AssoсiationSресiаlVo[r-rrrrе Sеriеs.5.5. Lсlndon:СhаpmanarrdHal[. Martirr,.|.\W.,аnd G. Е. Davis. 2001. Ап UpdаtеdСIаssifiсаti<'ltt of tbе Rесепt Спtstасеа.SсiеnсеSеriеsNo. 39. Lоs Arrgеlеs: Nаtural History Мusеumof Los A n g е l е sС o u n t v . Poсlrе'G. С. B. 2004. Маriпс Dесаpсlt!(',rustасеа сlf SсшthеrпАustrаliа:А Guidе ttl Idепti|iсаtirл.Сollirrgwood, Viс.: СSIRo PuЬlishing. Sсhram, F. 1986. Сrustdсесl.Nеw York: oхford Univеrsity Prеss.

-7.S.

Сuviеr, Gеorgеs(\769-18з2) Althсlugli GесlrgеsСtrviеr ехpliсitly rеjесtеd thе rlodifiсation of spесiеs, hе playеd a prominеnt rolе irr thе еarly history of еvсllutionarysсiеnсе,аlbеit involuntarily. In rеtrospесt,hе madе two major сontributions. First, hе еstаЬlishеd Ьеyond douЬt thе rеirlity of thе ехtinсtiorrof spесiеs' and hе showеd that this had оссurrеd frеquеntly irr tlrе histоrу of thе е:rrth'Sесond, hе undеrminеd thе idеa of thе grеat сhain of Ьеing;hе provеd it was impossiЬlе to сlassif1'organisms in a sеrial ordеr, еithеr logiсal or сhronologiсal. Frеnсh philosоphег Miсlrеl Еoшсаultsаid rhаt Сuviеr did rrrorеfoг thе еmеrgеnсеof еvolution than Jеan-BaptistеLamarсk or еarl1,аdvoсatеs of thе trаnsmutation thеory. Hош.еvеr,this rеtrospесtivееvаluation is historiсally mislеading. Cuviеr's аllеgеd сOntriЬutionstсl еvolutiсlnmust Ье plaсеd irr thеir own сontехt. Somе of Сuviеr's tlrеtlгiеsand rnеthods Wеrе indеес{inсorporatеd into thе sсiеnсе of еvtllution, Ьut thе еntirеty of Сuviеr's work сan Ье Ьеttеr undеrsttloс.l in light of a diffеrепt сonсеption of thе history of lifе. Сtrviеr was primarily a zoolсlgistаnd аn an21romist. Тhе main problеm for him was сlassifiсаtion. Hе saw сoшparativе аnatomy аs Ьеing сapaЬlе of providing a unifiеd thеory of living Ьеings. Ctrviеr's сomparativе anatomy и,as сlosеly rеlatеd to physiologу and to thе study of pаst oгganisпrs.From

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Сuuiеr thе Ьеginning of his сarеег to thе еnd, hе сombinеd anаtomiсal dеsсription and сlassifiсatiоnof animals, prеsеnt or ехtinсt' with physiologiсal hypothеsеs aЬout thеir funсtitlnal organization. Bесausеof his major disсoveriеsand mеthodologiсal innovаtions in this Ьroad fiеld of rеsеarсh,hе has oftеn Ьееn сonsidеrеd thе founding fathеr of Ьoth сomparativе and stratigraphiс palеontology. In Ьoth fiеlds, hе had prеdесеssorsand сompеtitors, Ьut hе playеd a dесisivе rolе in еaсh сasе. Historians of zoology (е.g.'Russеll L\9161 19s2) insist on thе first aspесt' whilе historians of palеontology (е.g., Rudwiсk 1976) emphasizе thе sесond aspесt. In Сuviеr's work, thе two dimеnsions сan hardly Ье dissoсiatеd.Nеvеrthеless' thеy arе rеflесtеdin thе titles of the two major synthеtiс Ьooks that hе puЬlishеd (Сuviеr 1812,1817). Although this is somеwhat artifiсial, thе two aspесts'stratigraphiсpalеоntology (еspесially thе thеory of еxtinсtion) and сomparatlvе anatomy, will Ье ехaminеd sеparatеly. In thе sесond half of thе sеvеntееnthсеntury, sеvеralsсiеntistsсlaimed that fossils сould Ье intеrprеtеd as rеliсs of еxtinсt spесiеs.But thе quеstion rе. mainеd opеn whеthеr thеsе spесiеs had indееd disappеarеd or still ехistеd somеwhеrе on thе еarth. For instanсе, l,amarсk, who dеsсriЬеd a hugе numЬеr of nеw invеrtеЬratе fossils' rеjесtеd thе idеa of ехtinсtion. Сuviеr proposеd to rеsolvе this quеstion Ьy using fossils of largе tеrrеstrial animals as а tеst. In сontrast with marinе animals, largе tеrrеstrial animals сould hardly rеmain unknown Ьy 1800. In 1796, Сuviеr gavе thе first dеtailеdproof of suсh a сasе. On thе Ьasis of drawings rесеivеd from Paraguay, hе idеntifiеd a giant fossil as an unknown animal rеlatеd to thе slсlths.Не сallеd this animal Меgаtherium. Thе сlaim tЬat МegаthеriumЬad disappеarеd was dесisivеly supportеd Ьy thе prесisе dеsсription of thе fossil, and its assignmеnt to a known fаmily (thе sloths). Latеr, Сuviеr ассumulatеd еvidеnсе aЬout thе disappеaranсеof а numbеr of othеr largе tеrrеstriаl animals (mammoth' mastodon, Pаlесiheriиm, and many spесiеs of fossil еlеphants,сroсodilеs, dееr, еtс.) in diffеrеnt parts of thе world. By usе of anatomiсal dеsсriptionsof unprесеdеntеdprесision' hе providеd сruсial support for thе сlaim that thеsе animals no longеr ехistеd. Bесausеmigration wаs unlikеly' only two hypothеsеsсould aссount for thе disappеaranсеof thеsе animals. At thе vеry timе whеn Lamаrсk Ьеgan publishing his transmutation thеory, in 1801 Сuviеr statеd thеy had Ьееn еithеr еntirеly dеstroyеd or modifiеd in thеir forms. Cuviеr rеjесtеd thе modifiсation hypothеsis Ьесausеhе thought thеrе was no еvidеnсеto support it. He advoсatеd thе ехtinсtion hypothеsis Ьесausе hе thought thеrе was еvidеnсе in its favor. Мummifiеd animals Ьrought Ьaсk from Еgypt Ьy Ёtiеnnе Gеoffroy Saint-Нilairе (Napсllеon'sехpеdition) did not providе thе slightеstсluе of thе modifiсation of animals Ьеtwееn antiquity and thе prеsеnt (sееfigurе).If no еvidеnсе of small сhangеs was availaЬlе' how сould Lamarсk and othеrs ехtrapolatе to largеr сhangеsovеr long pеriods of timе? In сontrast, Сuviеr and Alеxаndrе Brongniart's oЬsеrvations(1s0s) of the suссеssivеstratа aЬove thе сhalk in thе Paris Ьasin thus suggеstеdthе aЬrupt disappеaranсеof loсal fаunаs. Ovеr long distanсеs (grеatеrthan 100 kilomеtеrs),thеrе was а сonstant supеrposition of thе strata' еaсh strаtum with its сharaсtеristiсfossils. that

Part of GеorgеsСuviе mummifiеd organism him on his сampaign pointеd out is idеntiс that thеrеis no сhang

disappеarеd in thе n of frеshwatеr and m: sivе еvеnts of еlеvat junсtions Ьеtwееn t] сludеd that suddеn 1 tion of suссеssivеtеr from othеr plaсеs. As shown Ьy Мar tion...wasprimar viеr's gеnеral rеprеsс rеvolutions, whiсh t] migrаtion (in and or that сould havе dеst

Съшier Ьinеd аnatomiсal desсription :,with physiоlogiсal hypothее o f h i s m а j o r d i s с o v е r i е sa n d of rеsеarсh,hе has oftеn Ьееn rаtivе and stratigrаphiс palеrd сon-rpеtitors, Ьut Ье playеd , u s s е l l[ 1 9 1 6 ] | 9 8 2 ) g y ( е . g .R palеontology (е.g., Rudwiсk .'swork, thе two dimеnsions rе rеflесtеdin thе titiеs of thе J u v i е г1 8 1 2 , 1 8 | 7 \ . A l t h o u g h rtigrirplriсpalеontolсlgy(еspе. 'r anаtomy' will Ье еxаminеd sеvеralsсiеntistsсlaimеd that s p е с i е sB. u t r h е q u е s t i o n r е d disаppеarеdor still ехisted who dеsсгiЬеdа hugе nutnЬеr )xtinсtion.Сuviеr prop
,'t-

Pаrt of Gеorgеs Сuviеr's argumеnt agtrinst еvolution was Ьаsеd on thе murтrnifiеd organisms Ьrought Ьaсk Ьy Napolеon's sсiеntists,whrl went rvith him on his сamp:rign tсl Еgypt. Тhis is thе skеlеtсlrrof аn iЬis, whiсh Сuviеr pointеd out is idеntiсаl to thе skеlеtons of iЬisеs tсlda,v,thus apparеntlv showing thаt thеrе is no сh:.rngeovеr timе. (Fгom Сuviеr 1804.)

disappеarеdin thе nехt stratum. Fuгthеrmorе,thеy oЬsеrvеd an altеrnаtion of frеshwatеrand marinе forпr:rtions.This сould bе aссountеd for Ьy suссеssivе еvеnts of еlеvation and dеprеssionof thе сontinеntal arеas. Bесausе thе junсtions Ьеtwееn thе two kinds of strata Wеrе rаthеr sharp, Сuviеr сonсludеd that suddеn gеographiс сhangеs had Ьееn rеsponsiЬlеfor thе ехtinсtion of suссеssivеtеrrеstrialfaunas and for a rеpopulation by еxisting faunas frorrr othеr plaсеs. ..Сuviеr,s rеjесtiorrof еvoluAs shown Ьy Мartin Rudwiсk (1976, 117), tion . . . was primarily a dеfеnsеof ехtiпсtioп' not of spесial crеаtion.,' С:u. viеr's gеnеral rеprеsеntationof thе history of lifе сonsistеdin a sеriеsof loсal rеvolutions,whiсh thеmsеlvеsimpliеd thе ехtinсtiсlnof somе spесiеsand thе migration (in and out) of othеrs. Не nеvеr mеntionеd ir gеnеral сatastгophе that сould havе dеstroyеdall еxisting spесiеson еarth. Suсh a h,vpothеsiswas

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Сuuiеr mеntionеd latеr Ьy othеr sсiеntists (Alсidе d'OrЬigny in Franсе, William Buсkland in Еngland) who also аdvoсatеd еvеnts of ..spесialсrеation'' following thе ..сatastrоphеs.''Сuviеr had no thеory to aссount for thе divеrsitу of living Ьеings. For hirr.r,this quеstion was Ьеyond thе limits of thе positivе sсiеnсеof his timе. Although Cшr,iеrhad no thеo11,for thе origin and divеrsity of living organisms, hе lrad a thеOry of сlassifiсationthat rеliеd on thrее rational prinсiplеs. Thе first prinсiplе, thе prinсiplе of thе сonditions of ехistеnсе, statеs ..thе thаt diffеrеnt parts of еaсh Ьеirrgmust Ье сoordinatеd in suсh a Way to r е n d е r p o s s i Ь l еt h е е х i s t е n с еo f t h е b е i n g a s a w h o l е ' ' ( С u v i е r 7 8 1 7 , 1 : 6 \ . This prinсiplе doеs not rеfеr primarily to ехtеrnal сonditions' Ьut to thе nесеssarу сoadаptation of ir-rnсtionsand organs within tlrе animаl Ьody. Tlrе sесond prinсiplе, thе prinсiplе of сorrеlаtion of pirrts, is arl appliсation of thе formеr prinсiplе. It says that a givеn funсtion саnnot vаry without сorrеsponding m
181'2.Rесherсhеssur 1 8 1 7 [ 1 9 8 3 ]L. e R ё g sеruirdе bаsеа I,histoirс сompаrёе.4 vols.Paris: сontеmporarnеs. Сuviеr, G., and A. Brongniar еnvironsdе Paris.lol,lrпс Fouсault,N|. |966. Les mots Pаris:Gallimard. Rudwiсk, r|"[.t976. Thе Меа PаIаeontologу.Сhiсаgo: Ft Russеll,Е. S. 1916 ||982];. Мorphologу.Lo AпimаI СhiсagоPrеss.

Сuuiеr rbigny in Franсе, William s of ..spесialсrеation'' folto aссountfoг thе divеrsity r d t h е | i m i r so f t h е p o s i t i v e аnd divеrsity of living orе d t l n г h r е еr a t i o n a lp r i n с i ditions of еxistеnсе,statеs ordinatеdin suсh a Way to h o l е ' '( С u v i е r1 8 1 7 , | : 6 ) . сonditions'Ьut to thе nес:hin thе animal Ьody. Thе parts, is an appliсation of l сannot vary Without сorl praсtiсе'Сuviеr usеd this s in a fossil from thе shаpе for dеnying thе possiЬility ions in an organism are so rny сhangе in a givеn part rll of thе othеr parts. st Bегnard de Jussiеu, was 'еsthаt somе сharaсtеrs arе е y d е t е r m i n еa s е t o f p o s s i ;prinсiplеlеd Сuviеr to disrсtional typеs of animals: rsеtypеsWеrеnot rеduсiЬlе 1еous struсtural.funсtional y animals-and еvеn morе :. For Сuviеr thеrе was ntl rеd Ьy Lamaгсk) and no ullffroy Saint-Hilairе; sее thе ,' in this volumе).This was mon dеsсеntоf organisms. еmЬranсhеmеntsplayеd a . е d R u s s е |l W a l l a с е 'ns o t i o n rrеd fасts to idеas, and hе еithеrmodifiсation or spеfaсts supporting еithег hyl еvеnts of еxtinсtion and t.

ens.Аппаlеsdи Мusёиm

181'2.Reсhеrсhessur lеs ossеmепsfossilеsdes quаdrupёdes.Paris:Dёtеrvillе. 1817 |1983l.Lе Rёgпеапimаl distribиёd'аprёssoп rlrgапisаtioпpoиr seruirdе bаsей l'histoirепаturellеdеs апimаих et d'iпtrсlductioпЙ I'апаtomiе сompаrёе.4vols. Paris:Dёtеrvillе.Rеprint,Paris:Еditions dеs аrсhivеs сontеmporainеs. minёralogiquе dеs Сuviеr,G., and A. Brоngniart.1808.Еssaisur la gёographiе еnvironsdе Paris.Jourпаl des Мinеs 23: 421458. Fouсаult,t^. 1966. Les mots et lеs chosеs:Uпе аrсhёologiedеs sсiепсеshumаiпеs. Pаris:Gallimаrd. Rudwiсk, N{. |976. Thе Меапing of Fossils:Еpisodеsin the Historу of Pаlаеoпtologу.Сhiсago:Univеrsityof Сhiсago Prеss. Form апd Fuпсtion:A Сoпtributiсlпto thе Historу of Russеll,E,.S. 1916 L1'9821. Aпimаl Мorphologу. London:John Мurray. Rеprint, Сhiсago:Univеrsityof Сhiсago Prеss.

-J.G.

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Darwin, Chаrlеs (1809_1882) Сharlеs RoЬеrt Darwin, thе Еnglish naturalist and еvolutionist,was Ьorn in thе town of ShrеwsЬury on FеЬruarу 12, 1809, thе samе day as AЬraham Linсoln aсross thе Atlantiс. Hе diеd on April 79,1882, at his homе in thе vil. lagе of Downе (Kеnt). Hе was thе author of oп thе origiп of Spесies' plЬlishеd in 1859, and hе is сonsidеrеdthе fathеr of еvolutionary thinking. Darwin's patеrnal grandfathеr was physiсian Егasmus Darwin, author o{ Zoonomiа (1794_7796), onе of thе еarliеst works proсlaiming еvolution. His fathеr' RoЬеrt Darwin, was also a physiсian as wеll as a monеу man' arranging mortgagеs Ьеtwееn aristoсrats with land and a nееd of сash and Ьusinеssmеnwith сash and a nееd of safе loans. Darwin's matеrnal grandfa. thеr was Josiah \Wеdgwood, thе man rеsponsiЬlе for industrializing thе pottеry tradе in Britain. Darwin сеmеntеd thе !7еdgwood сonnесtion furthеr .W.еdgwood. whеn hе marriеd his first сousin, Еmma Не and his wifе had 10 сhildrеn, sеvеn of whom livеd to adulthood. onе was Gеorgе Darwin, thе еminеnt physiсist and authоrity on thе tidеs. Сharlеs Darwin was еduсatеdfirst at ShrеwsЬury Sсhool, onе of Еngland's lеading privatе sсhools, and thеn sеnt to ЕdinЬurgh Univеrsity in thе footstеps of his fathеr and grandfathеr, intеnding to train as a physiсian. Unh,ppy in this dirесtion' hе еnrollеd at Сhrist's Сollеgе in thе Univеrsity of CamЬridgе, intеnding now to Ье an Angliсan сlеrgyman. Whilе at univеrsity' Ьoth in Sсotlаnd and Еngland, Darwin startеd to show a strong intеrеst in sсiеnсе,and Ьy thе timе hе graduatеd in 1831, senior sсiеntistshad startеdto spot Ьoth thе intеrеst and thе talеnt. Thе suЬstantial Darwin-!7еdgwood fortunеs mеant that Darwin nеvеr had prеssingfinanсial nееdsand сould always indulgе his passion for еmpiriсal inquiry. Divеrtеd from thе сlеriсal сarееr Ьy thе offеr of a voyagе on HMS Beаglе, undеr thе сaptainсy of RoЬеrt Fitzroy, Charlеs Darwin spеnt fivе yеаrs going around thе сoast of South Amеriсa and еvеntuаlly сirсumnavigating thе globе. Although hе was еngagеd аs a gеntlеman сompanion to thе сaptain, Darwin soon bесamе thе full-timе ship's naturalist, aссumulating еxtеnsivе сollесtions that hе shippеd homе' thus adding to thе alreаdy good opinions of his CamЬridgе mеntors. Darwin аlso madе ехtеnsivе travеls inland. Thе diariеs hе wrotе on thе voyаgе Wеrе thе foundation for a popular tгavеl Ьook titl'edThе Voуаgе of thе Bеаgle, first puЬlishеd as part of thе offiсial rесord of thе ship's travеls and thеn indеpеndеntly. Thеrе is no dоuЬt that Ьеing -t04

known and apprесiatе as a man of solid wort еntifiс сlaims a fair an Darwin's first systеn hе was trainеd Ьy Сar thе world is formеd Ь1 tastrophеs),thе grеatе Lyеll' whosе thrее-volt gеrly dеvourеd Ьy thе thеsis, arguing that tht Lyеll hypothеsizеdtha Ьеing transitory and a thе distriЬution of lan kind of watеr Ьеd, wh Ьrings on еlеvation in Darwin aссеptеdth . in the Lyеllian modе. islands? Lyеll arguеd t arguеd that it was imр just Ьrеak thе sеa surf lands аnd thеn thеy si thе sеa surfaсе,еven a plеtеly Ьеnеаth. Сharlеs Darwin's g In Glеn Roy, a small v indеntations around t as thеy wеrе knowni around watег that on latе 1830s, Dаrwin a arеa had mоvеd upwа thе Swiss sсiеntist Lo watеr Was a lakе, daп apprесiatеd his mista thinking in a сatastr of God. Darwin would not I As a young man prеpz tsеаglе voyagе his Ьеlit strongly in a God whс tеrfеrе with his сrеati thе writing and puЬli< likе many mid-Viсtor сism. Тhе Angliсan b сausе it insistеd that (

of organisms, suсh at Arсhdеaсon William I

Dаrшiп, Сhаrlеs

t and еvolutionist,was born in 09, thе samе day as AЬraham 9,1882, at his homе in thе vilЭп thе Оrigin of Speсiеs, puЬof еvolutionarythinking. tn Еrаsmus Darwin, author of works proсlaiming еvolution. an as wеll as a monеy man' ar_ lаnd and a nееd of сash and rs. Darwin's matеrnal grandfaЬlе for industrializingthе potWеdgwood сonnесtion furthеr wood. Hе and his wifе had 10 onе wаs Gеorgе Darwin, thе sЬury Sсhool, onе of Еngland's nЬurgh Univеrsity in thе footg to train as a physiсian. Un's Сollеgе in thе Univеrsity of :lеrgyman.Whilе at univеrsity, d t o s h o w a s t r o n g i n t е r е s ti n sеniorsсiеntistshad startеd to antial Darwin-.$Иеdgwoodforrarrсialnееdsand сould always r of a voyagе on НМS Bеаglе, D а r w i n s p е n tf i v е y е a г sg o i n g эntually сirсumnavigating thе a n с o m p a n i o nt o t h е с a p t а i n , ,ralistа . с с u m u l a г i n gе х t е n s i v е t o t h е a | r е а d yg o o d o p i n i o n s : ехtеnsivе travеls inland. Thе rtionfor a popular travеl Ьook as part of thе offiсiаl rесord of .hеrе is no douЬt that Ьеing

known and apprесiatеd Ьy thе gеnеral puЬliс сеmеntеd Darwin's fеputation as а mаn of solid Worth. This status hеlpеd latеr to givе his сontroversial sсi. еntifiссlaims a fair and fаvoraЬlе hеaring. Darwin's first systеmatiс intеrеsts as a sсiеntist wеrе in gеology. Although hе was trainеd Ьy Сambridgе profеssor Adam Sеdgwiсk, who Ьеliеvеd that thе world is formеd Ьy oссasional pеriods of grеat еrrrptionand turmoil (сatastrophеs),thе grеatеst influеnсе on Darwin was Sсottish gеologist Сharlеs Lyеll' whosе thrее-volumеwork, Priпсiplеs of Gесllogу (1830-1833), was еagеrly dеvourеd Ьy thе voyaging naturalist. Lyеll proposеd thе uniformitarian thesis,arguing that thе gеologiсal world is govеrnеd Ьy unЬrokеn law. Also, Lyеll hypothеsizеd that thе world is in a kind of stеady statе' with all сhangеs Ьеing transitory and а funсtion of altеring сlimatе Ьrought on Ьy сhangеs in thе distribution of land and sеa. Hе lookеd on thе surfасе of thе globе as a kind of wаtеr Ьеd, whеrе dеposition in onе arеa сausеs sцЬsidеnсеand thus Ьrings on еlеvаtion in anothеr arеa. Darwin aссеptеd this viеw сomplеtеly, and his first sсiеntifiс triumph was .Why in thе Lyеllian modе. doеs onе find сirсular сorаl rееfs around tropiсal islands? Lyеll arguеd that thеy arе thе tops of ехtinсt volсanoеs, Ьut Darwin arguеd that it was improЬaЬlе thаt all of thе volсаnoеs would сoinсidеntally just Ьrеak thе sеa surfaсе.Rathеr, hе arguеd, thе сoral grows аround thе islands and thеn thеy sink, with thе сoral growing еvеr upward to rеmain at thе sеa surfaсе' еvеn aftеr thе islаnds thеmsеlvеsmаy havе disappеarеdсomplеtеly bеnеath. Сharlеs Darwin's grеatеst sсiеntifiс еrror Was also in thе Lyеlliаn modе. In Glеn Roy, a small vallеy in Sсotlаnd' thеrе aге thrее horizontal' traсklikе indеntations around thе sidеs. !(/hat is thе rеason for thеsе paгallеl roads' as thеy wеrе known? All agrееd that thеy Wеrе thе rеmains of Ьеaсhеs around watеr that onсе fillеd thе glеn, Ьut whеrе is thе watеr now? In thе latе 1830s, Darwin arguеd that it had Ьееn sеawatеr Ьut that thе wholе arеa had mоvеd upward and nоw thе watеr was drаinеd. Shortly thеrеaftеr thе Swiss sсiеntist Louis Agassiz visitеd thе arеa; hе at onсе saw that thе Watеr was a lakе, dammеd Ьy iсе that had sinсе mеltеd. Еvеntually Darwin apprесiatеd his mistаkе' Ьut this took timе Ьесаusе Agassiz wrappеd his thinking in a сatastrophiс thеory that rеliеd hеavily on thе intеrfеrеnсе of God. Darwin would not havе oЬjесtеdto thе supposition that thеrе was a God. As а young mаn prеparing for thе сlегgy' hе wаs a sinсеrе Сhristian. on thе Bеаgle voyagе his bеliеfs сhangеd and hе Ьесamе a сommittеd dеist, Ьеliеving strongly in a God who workеd through unЬrokеn law and who doеs not intеrfеrе with his сrеation. This position lastеd for many yеars, right through thе writing and puЬliсation of tЬe Оrigiп. Thеn, toward thе еnd of his lifе, likе many mid-Viсtorian intеllесtuals,Darwin's rеligion fadеd into аgnostiсism. Thе Angliсan Ьaсkground was аlways vital to Darwin, howеvеr, bесausе it insistеd that God's dеsigning powеrs сan Ье sееn in thе adaptations сlf organisms, suсh as thе еyеs for sееing and thе nоsе for smеlling. Likе Arсhdеaсon.sИilliam Palеy, whosе I'Jаturаl Thеologу (1802 [1819]) Darwin

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Dаnuiп, Сhаrlеs rеad as an undеrgraduatе, Darwin Ьеliеvеd that thе most signifiсant fеaturе of thе living world is thаt it is сomplех and dеsignlikе,tо thе Ьеnеfitof individual organisms. Lyеllian gеology dirесtеd Dагwin to thinking aЬout organisms; fossils wеrе vital еvidеnсе of subsidеnсеand еlеvation. Thus primеd, in 1835, whеn thе Beаglе rеaсhеd thе Galipagos Arсhipеlago' a group of islands in thе Paсifiс, Г)arwin was astoundеd to lеarn that thе dеnizеns, partiсularly thе Ьirds and thе giant tortoisеs' аrе diffеrеnt from island to island. Еvolution from a сommon anсеstry is thе oЬvious answеr' еspесiallyto sot-neonеwho Ьеliеvеsthat God's glory is shown through the working of law. Howеvеr, it was not until hе rеturnеd to Еngland in thе following spring of I8З7 аnd was сonvinсеd that thе Gal6pagos variеtiеsaге truly diffеrеnt spесiеsthat Darwin madе thе lеap to tгansformism, as it was thеn сallеd. Darwin rea|ized thаt hе nееdеd a mесhanism to ехplain his nеwfound Ьеliеf. As a graduatе of thе Univеrsity of СamЬridgе, hе was awarе of thе triumphs of its grеаtеst sсiеntist, Isaaс Nеwton. Darwin thеrеforе sought for thе organiс world a kind of еquivalеnt of Newton's univеrsal law of grаvitation. Hе found his answеr in SеptеmЬеr 1838. Hе startеd with thе Мalthusiаn саlсulation that populагion prеssurеswill tеnd to outstrip suppliеs оf food and spaсе. Hе notеd that thеrе sееmsalways to bе a sourсе of variation in natural populations. Hеnсе, arguing analogiсally from thе suссеssеsof thе Ьrееdеrsof animаls and plants, Darwin сonсludеd that thеге will Ьe a natural form of sеlесtion, with somе winning and othеrs losing, and suссеss Ьеing a funсtion of thе winnеrs' pесuliar fеaturеs. Vitally, this natural sеlесtion, oг ..survival of thе fittеst,''as it Ьесamе known, lеads not just to сhangе but to сhangе in thе dirесtion of adaptation. Darwin soon Wrotе up his thinking as a skеtсh of a thеory' Ьut for rеasons still undetеrminеd hе did not puЬlish. UndouЬtеdly a factor was that hе fеll sеriously ill аnd for thе rеst of his lifе wаs an invаlid and a rесlusе. (Thе еxасt сausе of thе illnеss is unknown. Somе spесulatеthat it was psyсhologiсal, thе strеss of having suсh an еvolutionary thеory. Othеrs think it might havе Ьееn thе rеsult of аn illnеss,Сhagas disеasе,piсkеd up on thе Bеаgle voyаgе.) For mаny yеars, Dаrwin sat ol.l his еvolutionary thinking and was divеrtеd into a massivе taxonomiс study of Ьarnaсles. .!Иallaсе, Finally' in Junе 1858, Alfrеd Russеl a young naturalist wгiting from thе Fаr Еast, sеnt Darwiп a short еssay сontaining thе samе idеаs Darwin had 20 yеars Ьеforе. Thus spurrеd, ехtraсts of Darwin's thinking and .lfallaсе's еssay Wеrе puЬlishеd at onсе. Darwin now rapidly Wrotе up his thеory, puЬlishing oп the origitl of Speсiеsаt thе еnd of 1859. TЬe Оrigin was immеdiatеly сontгovеrsial, Ьut it is important not to еxag. gеratе this fасt. In Britain and оn thе Сontinеnt, and еvеn in Amеriсa, many pеoplе, Ьoth sсiеntisсsand thе gеnеral population, quiсkly aссeptеdthе idеa of еvolution. Darwin himsеlf hаd laid thе groundwork for this Ьy сarеfully сultivаting mеn-notaЬly anatomist Thomas Hеnry Huхlеy and Ьotanists Josеph Hookеr in Britain and Asa Gray in Amеriсa-who would dеfеnd his

thinking puЬliсly. Thе rt also (aftеr a dесаdе or t ism. lWhat is сlеar is thа tion than for Darwin's < to dеny thе lаttеr outr: сausеs) ranging fгom L tiсs) to saltationism (еr

somе kind of guidеd еvс Darwin had intеndес would now writе, filling only onе of thеsе Ьoo Plапts цпdеr Drllиesttcс inadеquatе hypothеsis that partiсlеs arе givеn. Ь y г h е s е х о r g a n s .T h i s to whiсh Darlvin alwaу Apart from a sеriеs о tlе Ьook on orсhids, a plants, yеt anothеr on yеars Wеrе on thе hum

and a kind of supplеmе mаls (|87z\.In thе or aЬout humans, othеr tl that hе thought his thес thе topiс unintеrеsttng thеory on thе taЬlе ant mеnt about humans. In this,Darwin was' thе impliсations for Ho plе wantеd to talk aЬ< prеssurе from friеnds a that lWallaсе had Ьесon to ехplain hulnan еvo physiсal and soсial, rs i tion was thе kеy сausa ary mесhаnism, sеxu Darwin Ьеliеvеd that l

mining thе diffеrеnсеs Although hе did not last dесadе.Hе сontinu growing сorrеspondеn еrs асross thе wоrld as with rеspeсt and affес hе diеd' Ьy gеnеral aсс from Nеwton and a pа

Dаrшiп, Сhаrlеs thе most signifiсant fеaturе рlikе, tо thе Ьеnеfit of indiЬоut organisms1fossils wеrе primеd' in 1835, whеn thе эup of islands in thе Paсifiс, s' partiсularly thе birds and land. Еvоlution from a сom) somеonеwho Ьеliеvеs that v. Howеvеr, it was not until of 1837 and was сonvinсеd lесiеs that Dаrwin madе thе to ехplain his nеwfound Ьеgе' hе was аwаrе of thе tri)arwin thеrеforе sought for l n . su n i v e r s а l а w o f g г a v i t a {е startеd with thе Мalthutеnd to outstrip suppliеs of ,s to Ье а souгсеof variation Llly from thе suссеssеsof thе еd that thеrе will Ье a natuеrs losing, and suссеss Ьеing lly, this natural sеlесtion, or .ds not just to сhangе Ьut to r of a thеory, but for rеasons :dly a faсtor was that hе fеll valid and a rесlusе. (Thе еxrtеthat it was psyсhologiсal, . othеrs think it might havе еd up on the Bеаgle voyagе.) y thinking and was divеrtеd ' a y o u n g n a t u r a l i s tw г i t i n g :rtainingthе samе idеas Dar_ ts of Darwin's thinking and n now rapidly wrotе up his rе еndof 1859. t it is important not to еxag. ' and еvеn in Amеriсa' many ln, quiсkly aссеptеd thе idеa :rdwork fоr this Ьy сarеfully { е n r yH u x I е y а n d Ь o t а n i s t s riсa_whо would dеfеnd his

thinking puЬliсly. Thе rеligious tеndеd to Ье morе rеluсtant, Ьut thеsеpеoplе also (аftеr a dесadе or so) mоst proЬaЬly aссеptеd somе form of еvolutionism. What is сlеаr is that thеrе was сonsidеraЬly morе еnthusiаsm for еvolution than for Darwin's own mесhanism of natural sеlесtion.No onе wanted to dеny thе lattеr outright, Ьut most wantеd to supplеmеnt it with othеr сausеs' ranging from Lamarсkism (thе inhеritanсе of aсquirеd сharaсtеristiсs) to saltationism (еvolution Ьy instantanеous mаjor rrеw variations) to somе kind of guidеd еvolution whеrе God plаys a сontinuing and aсtivе rolе. Darwin had intеndеd tЬ'e Оrigiп to Ье a tеаsеr for a sеriеs of Ьooks hе would now writе, filling out in dеtail all thе сlaims madе Ьriеfly in tЬe origiп. only onе of thеsе Ьooks was еvеr writtеn, Thе Vаriаtioп of Aпimаls апd Plапts under Dсlmеstiсаtiсlп (1868\, notаЬlе сhiеfly for Dаrwin's somеwhat inadеquatе hypothеsis aЬout hеrеdity, сallеd pangеnеsis. (Darwin arguеd that partiсlеs arе givеn off all ovеr thе Ьody and сollесtеd in and transmittеd Ьy thе sех oгgans. This would thus еnsurе Lamarсkian еffесts,а hypothеsis to whiсh Darwin always suЬsсriЬеd.) Apart from a sеriеs of inсidеntal works that Darwin now authorеd-a littlе Ьook on orсhids' anсlthеr сln сlimЬing plants, a third on insесtivorous plants, yеt anothеr on еarthworms-thе major laЬors of thе post-Оrigi|1 yеars wеrе on thе human spесiеs,rеsulting in The Desсеnt of Мап (1871) and a kind of supplеmеnt,Тhe Ехprеssioп of thе Еmotioпs iп Мап апd Апimаls (7872|' |n tЬe Оrigiz, dеliЬеratеly, Darwin had said virtually nothing aЬout humans' othеr than an unamЬiguous сommеnt at thе еnd suggеsting that hе thought his thеory also appliеd to humans. It was not that hе thought thе topiс unintеrеstingor unimportant' Ьut hе wantеd first to gеt thе Ьаsiс thеory on thе taЬlе and not gеt еvеrything at onсе lost in thе gеnеral argumеnt аЬout humans. In this, Darwin was only partially suссеssful.At onсе, еvеryonе sеizеd on thе impliсations for Homo sаpieпsof thе ..monkеy thеory.''This is what pеoplе wantеd to talk aЬout. For a whilе, Darwin stayеd aloof. Thеn, undеr prеssurеfrom friеnds and supportеrs,and pаrtiсularly gаlvanizеd Ьy thе faсt that \Х/allaсеhad Ьесomе a spiritualist and had turnеd to non-natural сausеs to еxplain humаn еvolution, Darwin arguеd in dеtail that human naturе' physiсal and soсial, is a produсt of unЬrokеn law. As always, natural sеlесtion was thе kеy сausal featurе, Ьut Darwin supplementеdit with a sесond. ary mесhanism, sехual sеlесtion, whеrе organisпrs сompеtе for matеs. Darwin bеliеvеd that sеxual sеlесtion was partiсularly important in dеtеrmining thе diffеrеnсеs Ьеtwееn human sехеs and raсеs. Although hе did not livе to a vеry old agе, Darwin's hеalth improvеd in his last dесadе.Не сontinuеd to work until thе еnd, inсluding answеring an еvеr. growing сorrеspondеnсе.Aсknowlеdgеd both Ьy his сountrymеn аnd Ьy othегs aсross thе world as Onе of thе grеat sсiеntists of all timе, he was rеgardеd with respeсt and affесtion. Тhеrе Was thеrеforе no grеаt surprisе thаt whеn hе diеd, Ьy gеnегal aссIaim,hе was Ьuriеd in $7еstminstеrAЬЬеy, just aсross from Nеwton and a paсе or two away from Lyеll.

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Dаrшiп, Еrаsmus BlвLloGRAPHY Brownе,J' 1995. Сhаrles Dаrtuiп:A Biogrаpbу.Уol. 1, Voуаglиg.Nеw York: Knopf. 20О2.СhаrlеsDаrшiп: A Biogrаphу.Yo|, 2, Thе Poшеr rlf PIасe.Nеw York: Knopf. Darwin, с. 1839.lournаl of Rеseаrchesiпto thе GеologуапdNаturаl Нistorу of thе VаriousСouпtriesvisitеd bу HМS Bеаgle.London: Hеnry СolЬurn. 1859. Оп thе Оrigiп of Spесiеsbу Меапs of NаturаI Seleсtioп,or the Prеsеruаtioпof FаuourеdRасеsiп the Strugglеfor Lifе, London:John Мurray. 1868. Thе Vаriаtioпof Апimаls апd Plапts uпder Domеstiсаtioп.London: J o h nM u r r а y . 1871. Thе Dеsсепtof Мап' апd Sеlесtioпiп Relаtioп /o Sex. London:John Мurray. 1872. Thе Ехprеssiсlпсlf the Еmotirlпsiп Маn апd Апimаls.l,оndon:John Мurray. Darwin,Е.[1794*1796]l801. Zooпomiа;or,-ГhеLаtasof ОrgапiсI'ifе.3rdеd. London:J. Johnson. Lyеll, С. 1830-1833. Prinсiplеsof Gеologу:Bеiпg аn Аttеmpt to Ехplаin thе Formеr Сhапgеsiп the Еаrth'sSиrfасеbу Rеfеrепсеto СаиsesNrл,uiп Оperаtioп.3vols.London:John Murray. Palеy,W. [1802l1819.Nаturаl Тhеologу(СollесtеdWсlrks,vol.4). London: Rivington. Rusе' M. 1979. Thе DаrtuiпiапRеuolutioп:SсiепсеRеd iп Tooth аnd Сlаtu. Сhiсago:Univеrsityof ChiсagoPrеss. 2О08.Сhаrlеs Dапuiп. Oхford: Blaсkwеll. .Wallасе, A. R. 1858. On thе tеndеnсyof variеtiеsto dеpartindеfinitеlyfrom thе оriginal tуpе.lourпаl of the Proсеediпgsof thе l-iппеапSoсiеtу,Zoologу 3: -^4.R. 5З_62.

Darwin, Еrasmus (\7 3!_\802) Еrasmus Darwin, thе grandfathеr of Сharlеs Dаrwin, was onе of thе bеstknown early еvolutionists. A physiсian' hе livеd in Litсhfiеld in thе Еnglish Мidlands and latеr in DеrЬy, also in thе Midlands. Hе fathеrеd thrее sons with his first wifе, thеn two daughtеrs with a mistrеss, and sеvеn morе сhildrеn with his sесond wifе. Hе was opеn in his еnthusiasm for sеХual aсtivity' and to this еnd hе dесidеd' as a young man' to givе up drinking lеst it impаir his prowеss. A grеat еnthusiastfor Linnaеan taхonomy, Ьasеd as it was on sexual сharaсtеristiсs,Darwin was known to thе widеr puЬliс as a poеt whо hymnеd thе virtuеs of plant sехuаlity' Thе Louеs of tbe Plапts (1789) Ьеing onе of his majоr litеrary aсhiеvеmеnts. Еrasmus Darwin was а сlosе friеnd of industrialistsinсluding pottеr Josiah .s(еdgwood, whosе daughtеr marriеd Еrasmus's third son, RoЬеrt, and onе of whosе сhildrеn was Сharlеs. Kееnly intеrеstеdin maсhinеs and thеir usеs, Еrasmus Daгwin was a mеmЬег of thе Lunar Soсiеtу, a group of mеn who mеt monthly to disсuss mattеrs of intеrеst. This group inсludеd сhеmist .UИatt, famous for Josеph Priеstlеy, industrialist Matthеw Bolton, and Jamеs his work on improving thе stеam еnginе. Darwin was himsеlf an invеntor, inсluding a horizontal windmill' an untippaЬlе сarriagе, and а сanal lift for

Ьargеs. Hе was also i thе topiс. For his twtl hе wrotе a small trеаt FIе сoгrеspоndеd v onе aсquaintanсе v thinkеrs of his day, D

thе Frеnсh Rеvolutiо tion of an еnormous . сausе hе was a Ьrilliа mеn of his day; King

physiсian. Darwin's intеrеstir tiсularly thosе thrоwr tunnеls for сanals.Bu hе aсtually startеd wl (7794-1796), сarriеd еral of his poеms. A1 dards, Darwin mak attеntion to thе simil is сallеd homolоgiеs) a сamеo for what h floatеd thе idеa that is сallеd Lamarсkism nism of sехual sеlесt Truly, howеvеr, fс thе сhangе of organi of сhangе in soсiеty vanсеd, that is to sаy monаrсh (Ьuttеrfly)t Darwin's latеr poеm

Organ was Ь First fr Movе Thеsе Nеw p

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o|. 7, Vtlуаgiпg.Nеw York: 2, Тhе Poшer of Plасе. Nеw York: eologу апd Nаturаl Historу of L o n d o l r :H е n r y С o l Ь u г n . сlf Nаturаl Sеlесtioп, or thе э for Lifе, Ltltlсlon:John N4urrаy. s uпdеr D о nrcsti саtit.ltl. Londсln: iп Rеlаtion,o Sex. London: John Mап апd Апimаls. London: John ' Lашs of Orgапiс Life.3rd еd. аn Attеt|1pttrl Ехplаiп tbе ?rепсеto Саusеs Noш in td Works, vol.4). London: t' Rеd ill Тot'th аnd Сlаtu.

o dеp.rгtindеfinitеly from thе : Liппесlп Soсiеtу, Zoologу Зз

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Darwin' was onе of thе Ьеstlеd in Litсhfiеld in thе Еrrglish llands. Hе fathеrеd thrее sons mistrеss'and sеvеn morе сhil. е n t h u s i а s mf o г s е х u а l a f i i v i t y , l g i v еu p d г i n k i n gl е s ri t i m p а i г tаxonomy' Ьasеd аs it was on :hеwidеr puЬliс as a poеt who ,uesof thе Plапts (1789) Ьеing trialistsinсluding pottеr Josiah 's third son, RoЬеrt' and onе of . d i n m а с h i n е sa n d t h е i r u s е s , Soсiеty, a group of mеn who This gгoup inсludеd сhеmist r, and Jamеs lй/att, famous for rwin was himsеlf an invеntor' е сarriagе'and a сanal lift for

writing а sсiеntifiс trеatisе on Ьargеs.Hе wаs аlso intеrеstеdin agriсultr.rrе, thе topiс. For his two middlе сhildrеn, whonr hе sеt up in thеir own sсhool' hе wrotе a small trеatisеon fеmаlе еduсation. Hе сorrеspondеd with pеoplе far and widе on topiсs of mutual intеrеst. onе асquаintanсе Was Bеniamin Franklin. Likе many morе advanсеd thinkеrs of his daу, Darwin approvеd of thе Amеriсirn Rеvolution, as wеll as thе Frеnсh Rеvolшrion,шntil it got out of hand. A mаn of grеat girth, a funсtion of an еnormous irppеtitеthе was nеvеrthеlеssа wеlсomе housе guеst Ьесausе l"lеwas a Ьrilliant сonvеrsationirlist.Не wаs onе of thе wisеst mеdiсal mеn of his da-v;King Gеorgе III unsuссеssfullyЬеggеd him to Ье thе royal physiсian. Darwin's intеrеst in еvolution sееms to havе Ьееn spaгkеd Ьy fossils, partiсularly thosе thrown up in thе сoursе of boring through mountains to makе tunnеlsfor сanals. But it was not until virtually thе last dесаdе of his lifе thаt hе aсtually startеd writing on thе suЬjесt.Нis murjorprosе work, Zoonomiа (|794-1796), сarriеd disсussion of thе topiс' anсl tlrе suЬjесt еntеrs into sеvеral of his poеms. Although his thinking is somеwlrat сrudе Ьy today's standards, Dаrwin r.rrаkеsirrlportаnt points' still vаlid' еspесially drawing аttеntiontсl thе sinrilаritiеsЬеtwееndiffегеntkinds of organisms (wlrаt today is dеvеlopr.пеnt is сallес]homologiеs)and to thе possiЬilltv tlrаt еn-rЬrуologiсal Darwin thе agеs. Сausally, a сamеo for whirt happеns to spесiеs througlr flоatеd thе idеa that aсquirеd сhаraсtеristiсsr-nightЬе inhеritеd (what today is сallеd Lamarсkism) as wеll as offеring a vеrsion of his grandson's mесhanism of sеxual sеlесtion. Truly, howеvеr, fсlr Еrasmrrs Darwin, as for еr,еry othеr еarly еvolutionist, thе сhangе of orgаnisms ovеr timе was takеn to Ье a rеflесtion of and proоf of сhangе in soсiсt'vovеr timе-сhangе from a sinlplе statе to onе morе advanсеd,that is to s.1у'сharrgеof a progrеssivеnatltrе.As 1rеusеd to say, fгom (king). This ссlпrеstlrrough сlеarlу in onе of monаrсh (Ьuсtегflv)tсl t-t-tot-tarсh Darwiп's liltег poеms. TЬе Теmplе of Nаturе. С)гganiсLifе Ьеnеaththе shoгеlеsswavеs W:rs Ьorn аnd nurs'd in Oсеan's pеarly сavеs; First forms minutе' unsееn Ьy sphеriс glass, Movе on thе mud, or piеrсе thе wаtеry mаss; Thеsе, as suссеssivеgеnеrationsblоom, Nеrv powеrs aсquirе, and largег limЬs аssumе; .VИhеrrсе сountlеssgroupS of vеgеtationspring, And Ьrеathing rеalms of fin' and fееt,and wir-rg. T h r r st h е t a l l O a k , t h е g i а n t o f t h е w o o d , \Whiсh Ьеars Britаnnia's thundегs on thе flood; .Whalе, Thе unmеasurеdmonstеr оf thе main' Tlrе lordly Lion, monarсh of thе plаin, Thе Еaglе soaring in thе rеalms of eir, Whosе еyе undazzlеd drinks thе solаr glarе, Impеrious man, who rulеs thе Ьеstiirlсrowd,

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Dаrшiп, Еrаsmus Of languagе' reason' and rеflесtionproud' .i7ith Ьrow еrесt whtl sсorns this еarthy sсld, And stylеs himsеlf thе imagе of his God; Arosе from rudimеnts of form and sеnsе, An еmЬryon point, or miсrosсopiс еns! (Darwin 1803, 1: Сanto I, linеs295_з14) In arguing thus, Еrasmus Darwin was gсling against a ЬiЬliсally inspirеd aссount of origins, Ьut thе aсtual disagrееmеntwith Gеnеsis Wаs nеvеr a ma. jor impеdimеnt in thе еyеs of Сhristians, most of whorn Ьy his day Wеге not litеralists (in thе sеnsе of todаy's сrеationists).Мorе oЬjесtionaЬlеwаs thе faсt that progrеss' whiсh dеpеnds on thе еfforts of individual humans, was sееn to сonfliсt with thе idеa that salvation сan сomе only through Providеnсе, or God's unmеritеd graсе. That сonfliсt did makе еvolutiоn a radiсаl idеa' сompoundеd Ьy thе faсt that thе vilе dсlсtrinе wаs sееn tсl havе lеd to thе Frеnсh Rеvolution. Darwin himsеlf wаs а dеist, somеOnеwho Ьеliеvеsin God аs an unmovеd movеr. Thе faсt that еvolution is groundеd in thе rulе of law would havе Ьееn, for him, a proof of God's еxistеnсе and powеrs rathеr than a rеfutation. In thе еnd, Еrasmus Darwin's rеputation was dеstroyеdЬy a savagеparody of his poеtry writtеn Ьy politiсal сonsеrvativеs,inсludirrgGесlrgеСаnning, a British statеsman during thе Napolеoniс еra and latеr, Ьriеfly, primе minis..Thе Lovеs tеr. In thе funny of thе Triаnglеs'' (1798), Daгwin's spесulаtions aЬout plant sехuality and inсlinations (in an еarliеr poеm' The Loues of tЬе Plапts) wеrе moсkеd. Thеrе Wеrе сеrtainly thosе whсl studiеd Dаrwin's idеas with саrе, inсluding thе agеd Immanuеl Kant in KonigsЬurg, who rеad a Gеrman translation o{ Zсlсlпсlmiс. Nеvеrthеlеss, gеnеrаlly, еnthusiasm fсrr his thought wеnt into stееp dесlinе. Pеrhaps somеwhat unfairly, for postеrity hе takеs sесond plaсе to thе latеr, and no morе sophistiсatеd,writings of Frеnсh Ьiologist Jеan-BaptistеLamarсk. BIвLIoGRAPHY Сanning,G., H. Frеrе,and G. Еllis' 1798.Thе lovеsof thе trianglеs. Aпti-Jасobiп, 16 April, 23 April, and 17 May. Darwin,F,,1789.ThеBotапiсGаrdеп(PаrtlI,The I-ouеsof tbе Plапts).l-ondon: J.Johnson. [1794_1796]18О1. Zсхlпomiа;or, Тhе I'ашs of Оrgапiс l'ifе. 3гd еd. London:J. Johnson. 18О3.Thе Tеm1llеof Nаtиrе. Lсlndon:J. Jсlhnsсln. King-Hеlе,D. 1963. ЕrаsmиsDаrш,iп:Grапdfаthеrof Сhаr!еsDапuitt. Nеw Yсlrk: SсriЬnеr. МсNеil, М. 1987. Uпdеrthе Bаппеrof Sсicпсе:ЕrаsmиsDаrшiп апd His Аge. Мanсhеstеr:МanсhеstеrUnivегsityPгеss. Rusе,N4. 1999.Муstеrу сlf Муstеriеs:ls Еutllutirlпа SrlсiаlСrпstrцсtioп| -М.R. СamЬridgе,MA: Harvаrd UnivеrsityPrеss.

Dаnaiп апd thе Еn Nlind аnd Behаuiot

Iл Ьis Dаrouin апd the Е, h а u i o r ( l 9 8 7 ) . R o Ь е r tJ that hovеr around biolo t е l l i g е n с е .r е а s o n ,h а b i т arе frеquеntly usеd to rn and thеrе is nothing likе Сan thеsе human сha thеmsеlvеs funсtiоn as swеfs to thеsе two quеst as Еrasmus Darwin' Pi through Сhаrlеs Dаrwi latеr Darwinians suсh z Baldwin, and William.

сеntury. As always' Сharlеs D noг thе solе' mесhаnis human traits. Howеvеr, uralistiс. Somе of Dаrw did not. !7allaсе Ьеgan gеnеratеd Ьy natural sе joinеd with HеrЬеrt Spt A сommon Ьеliеf am i a n t h е o г y с r u s h е dn i n vеrsе and purgеd nаturt on Ьoth сounts. Pеrha Ьеliеfs of fundamеntаlis а l i s t s .D a г w i n a n d h i s d thеntiс moral sеnsе. Thе sесond issuе сo

nisms for еvolutionary topiс has Ьееn usually win, Ьut Riсhards shov сеntury to thе latе tw( сonсеrns' Ьut latеr Dar did, at lеast not until t win, somе animals' wh mеnt movеs out from l

Ьеhaviors. Ovеr sеvе into nеw haЬits. Howl tеndеd to rеjесt thе Ba

vеry minor signifiсanс Baldwin Еffесt hаs ех Darwin originally thor

D:rrwin and thе Еmеrgеr-rсесlf Еvсllutionary Thесlriеs

)сtionрroud' his еaгrh1, sod, rf his God; t and sеnsе, :optсеns! э s2 9 5 - 3 1 4 )

Dаrt,ь,inаnd thе E,mergеncеof Еuolutionаrу Theories of Мind aпd Bеhаuior (RoЬеrt J. Riсhaгds)

lg agаinst a ЬiЬliсally inspirеd t with GеnеsisWas nеvеr a maг of whom Ьy his dаy Wеrе not ). Мorе oЬjесtionaЬlеWas thе l r t so f i n d i v i d u a l h u m a п s ' w а s сan сoll-lеonly tlrrough Pгovi_ t did mаkе еvсllutiсlna radiсаl )сtrlnеWas sееn tO havе led to сlеist,solnеonеwho Ьеliеvеsin rtion is gгou,ndеdin thе rulе of l's ехistеnсеand powеrs rаthеr s dеstroyеdЬy a sirvagеparody ; .i n с l u d i r l G g е o r g еС a n n i n g ,а r n d | а t е r 'Ь r i е t . l yp. r i m е m i n i s (1798 I' Dа гwit-t'sspесuiiltions larliеr poеm' Thе I'oues of the 'sеwho studiеdDarwin's idеаs rt in KonigsЬurg, ',vho rеad a s, gеnеrаlly,еnthusiasmfor his wЬat unfairly, fсlr postеrity hе phistiсatеd,writings of Рrеnсlr

s сlf thе triallglеs.Аnti-Jасobiп, Lrluеs оf thс Plапts). London: us of ()rgаttiс I'ifе. 3гс1еd. hnson. оf Сhаrlсs Dаrшiп. Nеw York: rsmusDttrшiп апd His Аgе. l Soсiаl Сoпstruсtiсllt?

-^4.R.

|nhis Dаrcuiп апd thе Еmеrgепсe of Еuolutirлаrу Thеoriеs of Мiпd апd Bеhаuior (|987), RoЬеrt J. Riсhards аddrеssеsthе most diffiсult sеt of idеas that hovеr around Ьioiogiсzrlеvolutiorr-thе еvolution of rrrind,insrinсt, in. tеlligеnсе,rеason' haЬits' аnd Ьеhavior.Thеsе idеas arе diffiсult Ьесausеthеy arе frеqr.rеntly usеd tо invеstigatеthеmsеlvеs.Riсhards also addrеssеsmorals, аnd thеrе is nothing likе moгаls to intегfегеwith thе study of nrorals' Сan thеsеhumаn сharaсtеristiсsеvolvе via natural sеlесtion' and сan thеy thеmsеlvеsfunсtion as a mесhanism in еvolution? Riсhаrds traсеs thе answеrsto thеsеtwсl quеstionsin thе works of suсh еighteеnth-сеnturysсholars as Еr:rstnus Darwin, Piеrrе-Jеan СirЬаnis, and Jеan-Baptistе dе Lаmarсk, .Wallaсе, through Сharlеs Darwin' Alfrеd Russеl and HеrЬеrt Spеnсеr, and latеr Darwinians suсh as Gеorgе J. Romanеs, С' Lloyd Мorgan, James I\4. Baldwin, аnd \WilliаrnJanrеs, aпd on up toward thе еnd of thе rwеr.rtiеth сеntury. As always, Сharlеs Daгwin viеwеd natural sеlесtionas thе сhiеf, although not thе solе, mесhаnism opеrating in еvolution, ir-rсludingthе еvolution of human traits. Howеvеr, аll of thеsеmесhanismswеrе for Darwin totally naturalistiс. Somе of Darwin,s сontеmporariеsfollowеd Darwin's lеad, Ьut most did not. \Vallaсе Ьеgan thinking thаt tlrе pесuliаrly humarr traits сould Ье gеnеratеdЬy naturаl sеlесtion.Latеr hе аЬandonеd Dаrwin on this sсorе and joinеd with HеrЬеrt Spеnсеr. A сommon Ьеliеf among prеsеnt-dayhistoriаns of Ьiology is that Darwin. ian thеory сrushеd ninеtееnth-сеnturyЬеliеf in а spirituаlly dominаtеd uni_ vеrsе and purgеd naturе of intеlligеntdеsign аnd purposе. Riсhаrds disagrееs on Ьoth сounts. Pеrhaps latеr Darwinians did not hold thе unsophistiсatеd Ьеliеfsof fundamеntalistСhristians, Ьut thеy wеrе hardly rесalсitrаnt mаtеrialists.Daгwin and his disсiplеsаttеmptеdto infusе human naturе witlr an authеntiс moral sеnsе. Thе sесond issuе сonсеrnеd suсh things as hal.litsfunсtioning as mесhanisms fсlr еvolutionary сh:rngе.Amоng historians of sсiеnсе irr tlrе pаst, this topiс h:rs Ьееn usually limitеd to parodiеs of Lamarсk and latеr Jamеs Bald. win, Ьut Riсhards shows thаt suсh Ьеliеfswеrе сommon frсlm thе еightееnth сеntury to thе latе twеntiеth сеntury. In faсt, it was onе of Darwin's main сonсеrns' Ьut latеr Darwiniаns did nоt pay as muсh attеntion to it as Darwin did, at lеаst not until thе еnd of thе ninеtееnthсеntury. Aссording to Baldwin, somе animals, whеn thеy еntеr a nеw еnvironmеnt or tЬеir old еnvironmеnt movеs out irom undеr thеm, сzrrradjust to thе сharrgеЬy lеarning nеw Ьеhavioгs. Ovеr sеvеral gеnеrations thеsе Ьеhaviors might Ье transmutеd into nеw haЬits. Howеvеr, in thе twеntiеth сеntury, еvolutionary Ьiologists tепdеd to геjесtthе Baldwin Еffесt as not oссLlrringat all or аs Ьеing of only vеry minor signifiсanсе.During thе past fеw dесadеs or so, howеvеr, thе Baldwin Еffесt has еxpеriеnсеd a rеsllг!]еnсе.МayЬе it is as impoгtant as Darwin oгiginally tlrought.

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Dаtukiпs In Dаrtc,iп аnd tbе Еmеrgeпcе of Еuolutionаrу Theories of Мiпd апd Bеhаuior, Riсhards еspousеs а гadiсal philosophy of histoгy-a selесtion modеl. Historians of sсiеnсе arе wеll awarе that the gеnеalоgy (who got what from whom) of idеas is important, Ьut rесonstruсting сonсеptual gеnеalogiеs is quitе diffiсult. Usually historians havе to sеttlе for similarity of idеas, and too oftеn, when sirrrilarity and gеnеalogy сonfliсt, thеy sidе with similarity. Riсhards doеs not. Не not only еspousеs a sеlесtion modеl of sсiеntifiс сhangе Ьut also Ptlts it into praсtiсе. His history is all thе Ьеttеr for it. вlвLIoGRAPHY Hodgе,J., aпd G. Radiсk, еds.2003' T,hеСаmbridgeСompапioпto Dаrшiп. СamЬridgе:СamЬridgеUnivеrsityPrеss. Riсhаrds,R. J. 1987. Dаrшiп апd thе l|mеrgепcеof ЕuolutiottаrуThеoriеsof Мiпd аnd Bеhаuiсlr. Chiсago:Univеrsityof СhiсagoPгеss. 1992. Thе Меапiпg of Еuolution:Thе МorphologiсаIСoпstruсtioпаnd IdeologiсаIRесс>nstruсtioп of Dаrlt,iп'sTheorу.Chiсago:Univеrsityof Сhiсago Prеss. |999, TЬe еpistеmologyof historiсalintеrprеtation:progrеssivityand rесapitulation in Dаrwin'sthеory.In R. Сrеathand J. Мaiеnsсhеin,еds., Еpistеm()logуапd B ioklgу, 64_9О.CаmЬridgе:CambridgеUnivеrsityPrеss' Rltsе,R. 2003. Dсlпuin аnd Design:Does Еuolиtion Наue а Purposе?Сambridgе' МA: Harvard UnivеrsityPrеss. WеЬеr,B. Н., and D. J. Dеpеw. 2003. Li,uolution апd Lеаrпiпg:Tbе Bаldu,,iпEffeсt Rесonsiderеd. СаmЬridgе' МA: MIТ Prеss.

-D,L.H.

Dawkins, Riсhard (ь. I94|) Riсhard Dawkins is a British zoologist and еvolutionary thеorist Ьеst known for his сonсеpts of thе sеlfish gеnе, thе еxtеndеd phеnotypе, and thе mеmе. Born in Kеnya, Dawkins was еduсatеd at Oxford' whеrе hе has livеd and workеd sinсе 1970. F{is 1976 Thе Sеlfish Geпe is onе of thе сlassiс works of nеo-Darwinism, unifying and сlaгifying thе еmегgingсonsеnsusаmong suсh еvolutionary thеorists as !(/illiam Hamilton, Gеorgе Williams, RoЬегt Trivеrs, John Мaynard Smith, and his doсtoral supеrvisor, еthologist Niko Tinbеrgеn. This Ьook artiсulаtrs thе thеory of nаtural sеlесtion in suсh vivid and aссеssiЬlе tеrms that it is oftеn mistakеnly rеgardеd as mеrеly a ..popular'' Ьook. Dawkins's сеntral сlaim is that thе most fundamеntal' and hеnсе most еxplanatory, pеrspесtivе on all еvolutlon by natural sеlесtion is thе .,gеnеЪ-еyе viеw,,' in whiсh Ьеnеfits to spесiеs, linеagеs, groups' and еvеn individual organisms arе sееn to Ье suЬsidiаry to thе primary Ьеnеfiсiariеs of all adapta..sеlfish'' gеnеs tions' thе thеmsеlvеs. ovеr timе' еvоlution designs and Ьuilds organisms (..survivalпraсhinеs'')that Ьеnеfitсoalitions of gеnеsЬy improving thеir prospесts for rеpliсation. TЬе геaсh of gеnеs doеs not stop at thе skin of thе oгganism: soпlе gеnеs сontrol thе dеsign and сonstruсtion of an еxtеndеd phеnotype' harnеssing fеaturеs of thе еnvironmеnt and еvеn othеr spесiеs. Thus thе bеavег'sdаm and thе spidеr's wеЬ arе just as important paгts of thе phеnotypеs of thosе spесiеs as thеiг еyеs and mouths' аnd parasitеs oftеn ехploit thе Ьеhaviorаl сontrols of thе host spесiеs' hiiaсking othеr gеnеs' survival

mасhinеs. Еmphasizing t . awkirl m е n t а l i r l s i g h t sD nattlral sеlесtion сгеatеd; that inсludеd languagе ar of еvolution Ьy natural sе сation of saliеnt сulturirl fеaturеs of сulturаl еvolu prеsеntеd thе idеil of mе аЬstraсtnеss of thе funс сlаimеd to Ье making a n еvolution of human сult thusiastiсally' with mixес In 1986' Dаlvkins put Wаtсbmаker, in wlriсh h е v o l u t i o n a r у r h е с l r yv i а thе еarly triumphs of th 1995' hе was appointеd liс Undеrstanding оf Sсi talеnts' hе has subsеquе plaining aspесtsof sсiеn thе puЬliс disсussionso N4ost rесеntly, his Ьroa tеmрt to raisе сonsсiou rеligious Ьеliеf,has attrа a l е a d i n g r o l е i n w l r a ti s thе lay puЬliс arе Dawk kin sеlесtion and thе еvс вlвLIoGRAPHY

Dawkins,R' 1976' Thе Sе |982. The Ехtсnd 1986.Тhе Bliпd \ 2О04.Thе Апсcst 2ОО6,Thе G
Thе Descent of Ма Relаtioп to Seх (С|

Tbе Dеsсепtof Мап, а wаs СharlеsDarwin'sv hе had Ьееnunwillingt whеrrAlfrеd RussеlWа сould not that hr-rmans thаt hе had to gеtinvol

ТIrеDеsсеntof Man шrу Theories of Мind апd Be. ophy of history-a sеlесtion rt thе gеnеalogy(who got what ruсting сonсеptual gеnеalogiеs rtlе for similarity of idеas, and fliсt, thеy sidе with similarity. sеiесtion modеl of sсiеntifiс ry is all thе Ьеttеr for it.

gеСompапioпto Dаrtuiп. { ЕuсllutionаrуTbеoriеs of Мind Prеss. phologicаlСonstructioпапd r,.Сhiсago:Univеrsityof Сhiсаgo rеtation:pгogrеssivityand . andJ. Мaiеnsсhеin, еds., l СambridgеUnivеrsityPrеss. 't Hаuеа Purposе?Саmbridgе' d Lеаrni пg:'',

u o.:В([:,n. "'

llutionаry thеorist bеst known lеd phеnotypе, and thе mеmе. сford, whеrе hе has livеd and z is onе of thе сlassiс works of lеrging сonsensus аmong suсh lorgе!Иilliams, RoЬеrt Trivеrs, or' еthologistNiko TinЬеrgеn' ;tion in sцсh vivid аnd ассеssias mеrеly a ..popular'' Ьook. lamеntal, and hеnсе most ехral sеlесtion is thе ..gеnе's-еyе :oups, and еvеn individual orrry Ьеnеfiсiaгiеsof all adapta. :, еvolution dеsigns and Ьuilds 'аlitionsof gеnеsЬy improving Lеsdoеs not stop at thе skin of d сonstгuсtion of an еxtеndеd mеnt аnd еvеn othеr spесiеs. iust as importаnt parts of thе loЦths,and parasitеsoftеn ехhijасking othеr genеs' survival

maсhinеs. Еmphаsizing thе univеrsal appliсation of Сharlеs Darwin's fundamеntal ir-rsights,Dawkins drеW attеntion to thе possiЬility th;rt whеn gеnеtiс naturаl sеlесtion сrеatеd a spесiеs,Hoпto sаpieпs, with an еxtеndеd phenotypе that inсludеd languagе and tесhnology' this in еffесt еstablishеd a nеw mеdium of еvolution Ьy natr'rralsеlесtion:human сulturе, in whiсh thе diffеrеntial rеpliсation of saliеnt сцltuгal itеrr-rs'сallеd шеmеs' соuid aссot-tntfoг rrrany of thе fеaturеs of сultural еvolution that arе Othеrwisе pеrplехing. Dawkins initially prеsеntеd thе idеа of mеmеs as a sort of thought еxpеrimеnt to illustrаtе thе аbstraсtnеssof thе fundameпtal idеa of natural sеlесtion. аnd hе has not сlaimеd to Ье making a major сontriЬr-rtionto thе sсiеntifiс invеstigation of thе еvolution of humаn сulturе. Othеrs, howеvеr, hаvе takеn up thе сonсеpt еnthusiastiс:rlly,with пriхеd rеslrlts to datе. In 1986, Dawkins puЬlishеd anothеr pеdаgоgiсaltour dе forсe,Тhе Bliпd Wаtсhпшkеr,in whiсh hе illr.rstratеd many of thе most еlusivе impliсarions of еvolutionary thеoгy via his pionееring Blind \Watсhmakеrsoftwarе, onе of thе еаrly triumphs оf thе Artifiсial Lifе п1ovеmentin thеorеtiсal Ьiology' In 1995,Ьe was app
The Descent of NIаn, аnd Selectioп in Relаtioп to Seх (СharlеsDarwin) Tbe Dеsсепt of Мап, апd Sеlесtiсlпiп Relаtioп to Seх, puЬlishеd in 1871, was Сhаrlеs Darrд.in'swork on thе evolution of thе human spесiеs.Initially, hе hаd Ьееп r"rnwillingto gеt into this asресt of tlrе еvolutionary dеbatе, Ьut whеn Alfrеd Russеl !7allасе (1870), who had Ьесomе a spiritualist, dесlarеd that humans сould not havе Ьееn produсеd Ьy natural mеans' Darwin fеlt that hе had to gеt involvеd.

.'1.]

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Thе Desсеntof Маn Littlе of thе Ьаsiс disсr-rssionof human еvolution is originаl, аs Darwin rеliеd hеavily on thе rеports and findings of othеrs. Likе Thomas Hеnry Huх. lеy (in Euidenсе аs to Мап's Plасе iп Nаturе, 186З) Ьеforе him, DarwinЪ сhiеf modе of аrgumеnt was to сomparе humans with othеr animals, showing that thе diffеrеnсеs arе a lot lеss grеat than сlnе пright imaginе. Thеrеforе, thеrе is no rеason to think that humans arе not part of the naturаl world, and, givеn thе sharеd fеaturеs with thе animals' mцсh rеason to think that humans arе thеir dеsсеndirnts.Dагwin did not think thаt humаns wеrе dе. sсеndеd trom animals alivе today, аnd hе was inсlinеd to support thе idеa of an Afriсаn origin for humankind. Darwin was pаrtiсulаrJy intеrеstedin humаn fеason аnd soсiality. Hе arguеd that morality (аnd rеiigion) arе nattrraloutсomеs of еvolution. Bесausе in еarliеr writings Darwin had Ьеliеvеd that natural sеlесtion works always 1Ъr thе bеnеfit of thе individual rathеr than thе group' hе was сonсеrnеd to show that a gеnuinе morаl sеnsеof саrе for othеrs сould nеvеrthеlеss еvolvе. In somе rеspесts' thought that a group kind of sеlесtion might havе pro-hе duсеd morality' Ьut hе also gavе thе suggеstion thаt morаlity .oulJ Ь. еnlightеnеd sеlf-intеrеst. Hеrе hе antiсipatеd thе modеrn mесhanism of ..rесipгoсal altruisnr..' !Иallaсе'sapostasy also ехplains thе rathеr odd nаturе of Darwin's Ьook, bесausе muсh of it was not aЬout humans at аll. It was rathег about Darwin's sесondary mесhanism of еvolutionary сhangе, that is, sеxual sеlесtion. Hеrе, organisrrrsin a spесiеs сompеtе for matеs, and hеnсе thеy dеvеlop adaptations (е.g.,antlеrs of the dееr, tail fеаthеrs of thе pеaсoсk) to аid in this сompеtition. !Иallaсе arguеd that fеaturеs likе humаn haiгlеssnеss and grеat intеlligеnсесould not havе bееn produсеd by natural sеiесtion аnd so must bе thе rеsult of spirit forсеs. Darwin rеpliесl that sехual sеlесtion сausеs many human fеatuгеs'suсh as intеlligеnсеand Ьody shapе. For marry yеars' pеoplе werе inсlinеd to dismiss sеxual sеlесrion аs somеthing dеmanding trеatmеnt in its
promotlng an unsllpPol Viсtoriаn, hе is a vеry l е f f е с t so f m е d i с i n е ,h е i l stop using it. Hе also t ovеrсomе othеr pеoplеs whitе pеoplе morе гap1 Мorе gеrrеrally,althouE thаt do sound likе Soс on many sourсеs, and Volkish sеr-rtimеntsof t} lеast as signifiсant, or m thе Nazis gеrrеrailydid nеss of humankind, linl disсussеs thеsе сhаrgеs вlвLIoGRAPHY

D а r w i n ,с ' 1 8 7 l . T h е D е John Мurray. ЕхpеIlеd:No Iпtеlligcllсе, N.p.: PгеnrisеМеdiа ( li F r i е t l l a n d е Sг '. l 9 9 ' . N с.W London: 19З.1-З9. G r u Ь е r ,М . Е . | 9 8 1 .D а r u H i t l е r ,A . | 9 2 5 .М с i п K а l Flu.хlеy,T . H. 7863.Еuid Norgatе. Kеrshaw,I. t999. Нitler. Riсhards,R. J. 2008. ТЙс Еuolutioпаrу Тhough Rusе, М. 2008. СhаrlesD Trivеrs,]t' L. 1971.Thе е Biolсlgу46: З5-57, .Wаllaсе, A. R. 1870.Thе Сoпtributiсltls ttl tbе Mасmillan. Wеikагt,R. 2006. FrсlmL Rасism iп Cеrmапу.

Thе Dеuelopment -Гbe

Dеuеlopmепt of l just a fеw months aftеr Thе Ьook асhiеvеd аn win Studiеs, thе histor Studiеs Ьесаnrеа spссi сеntеnnial of thе puЬli soon grеWinгoа majo duе to two faсtors. Fi еxtrеnrеly importаnt s

Thе Dеvеlopmеntof Darwin's Thеory llution is original, as Dаrwin rеhеrs.Likе Thomas liеnry Нuхrе' 186З) Ьеforе him, Darwin's nans with othеr аnimals' shown oпе might imaginе' Thеrеforе, ) not part of thе natural world, nals,пruсh rеason to think that rot think that humans wеrе des inсlinеdto support thе idеa of lan геasonand soсiality. Hе aroutсomеsof еvolutiorr.Bесause naturаl sеlесtionwoгks аlways thе group, hе was сonсеrnеd to lthеrsсould nеvеrthеlеssеvolvе. Lndof sеlесtionmight havе pro]еstion that morality сould Ье thе пrodеrnmесhаnism of ..rеr odd naturе of Darwin's Ьook, at аll. It was rathеr aЬout Darсhangе,that is, sеxual sеlесtion. mаtеs' and hеnсе thеy dеvеlop rthегsof thе pеасoсk) to aid in :еs likе human hirirlеssnеssand rсеdЬy natural sеlесtiоn and so n rеpliеd that sеxual sеlесtion еnсеаnd Ьody shapе. For many ual sеlесtion as somеthing dеLrglrtof it as sornеthing Ьеst inrisе of intеrеstin аnimal soсial of grеatthеorеtiсal and еmpirilas lеd to makе somе vеry сonэегiorityof malеs ovег fеmalеs, lso worriеd that modеrn mеdirn Ьrееdingstoсk, Ьut fеlt aЬlе suгеd pеoplе of сulturе whosе of thеsе sorts of rеmarks, thе t h ес r е a t i o n i s tas n d t h е i г а s s o :orists)' frustratеd in thеir atеliеfsarе gеnuinе sсienсе, havе in lеads straight tо thе vilе idеy National Soсialism (sее еspе-nаrratеd fr|m Ехpеllеd: No iс ехarnpiе of Ьаd sсholarship

promoting an unsuppoгtaЬlе thеo|ogiсal thеsis. Although Darwin is vеry Viсtoriaп' he is a vегy liЬеral Viсtori:rn. For all that hе worriеd aЬout thе еffесtsof mеdiсinе, hе immеdiatеly strеssеdthat lrе did not think wе should stop using it. Hе also thought that thе сhiеf rеasorr whitе pеoplе tеnd to ovеrсomеothеr pеoplеs is bесausе othеr pеoplеs suссumЬ to thе disеasеsof whitе pеoplе morе rаpidly than whitе pеoplе do to thе disеasеs of othеrs. Мorе gеnеrally' although thеrе аге indееd pаssagеsin Мeiп Kаmpf (1925) that do sound likе Soсial Darwinisпt' Hitlеr drеw somеwhat haphаzardiy on many sourсеs' and thе аnti-Sепritism of his youth in Viеnna аnd thе .Wagnеr Volkish sеntimеnts оf thе group promoting thе mеm
The Deuelopmeпt of Dапuiп's Theorу (Dov ospоvat) Thе Deuеlopmeпt of Dаrшiп's Thеorу wаs puЬlishеd in 1981. It appеarеd justa fеw months aftеr thе dеath of its author, Dov Ospovat, at thе agе of 33. Thе Ьook aсhiеvеd an important milеstonе in what Ьесamе known as Dаrwin Studiеs,tlrе histoгiсаl study of Сharlеs Darwin's lifе аnd work. Darwin StudiеsЬесamе a spесial arеa in thе histсlry of sсiеrrсеshortly aftег thе 1959 сеntеnnialof thе puЬliсation of Сhаrlеs Darwin's oп the origin of Spесiеs.It soon grеw into a mаior fiеld of historiсal rеsеarсh.Thе еxplosivе growth was due to two faсtors' Fiгst, until thе 1950s Darwin was l.lotrесognizеd as thе еxrгеmеlyimportant sсiеIrtistthаt hе is today. Thе modеrn synthеtiс thеory

515

516

Thе Dеvеlopmеntof Darwin's Thеоry сlf еvolution (thе thеory foгmеd Ьv сomЬining Dаrrvinian natuгal sеlесtion with Mеndеlian gеnеtiсsand, mеforе1959. ..Darwin was thе first rеputaЬlе lraturalist to arguе for transmutа.ttion who was аЬlе to takе advantagеof thе dеvеlopmеntalviеw of natllrе that еmеrgеd in thе mid-ninеtееnth сеntury. This, as nruсh as lris nеw thеory [natural sеlесtion],sеpаrаtеsDаrwin's work frсlm [Jеan-Baptistеll,amarсk's'' 1Ospo. v a t 1 9 8 1 .i 6 8 ) .

This nеw viеw сlf Dar' phologу and еmЬryoltlgу ginning in thе 1980s, wеl and еmbryologiсal dеvеlo thе stagе foг Ьroadеr his gathеrеd Ьy historian D;

Th е D аrц'ittiап Her itаgе portant was Ospovat's s' с o m l n i t t е d t o t h е n o t i r l nt jor intеrеst to historiаns

2 0 0 3 ,2 0 0 4 ) .

вlвLtoGRAPнY

Amundson,R. 200.5.TDeС/ Rсlotsof Еuo-dеuo.Сal Burian, R. М. 2004. Еуlistе псtiсs. СamЬridgе:Сlrп K o h n , D . , е d . 1 9 8 5 .Т h е D а Prеss. O s p o v а tD , . 1 9 8 1. T b е D e u UnivеrsityPrеss. R i с h a r d sR , . J . \ 9 9 2 ' Т h еN апd ldеolсlgiсаIRеа lпs СhiсagoPrеss.

200З, Тhe Rсlmсtltt of Gсlеthе. Сl.riсllgсl: LII

2004.MiсhaеlRus 2s-38.

Rusе, М. 1996. Мoпаd to ] СarnЬridgе, MA: Наrv 2004.Тhе r
Dinosaurs: Thе mor

Bесaцsе of thеir immеt.t first сolте to mind wl-rе plеd with thе faсt that сеntury Еngland) wlrеrе t h е i r h i s r o r i с e l l yЬ е i n gu t е х t , d i n o s а u r sh a v е p I

аЬour еvolution. Nеvеr d е v е l o p i n gа m o г е s с i е and undеrstandingеvol Dinosaurs arе a unlq thеir еrесt postuге and '

most sLlссеssfultеrгеst spirnnеd thе pегiod fror

Diпosаurs rg Dаrwinian natural sеlесtion with molесular gеnеtiсs)Ьеgan stratеdthаt a numЬеr of diffеrd gеnеtiсdrift, сontriЬutеd to гhs of thеsе influеnсеs was un:d that natural sеlесtion Was thе ; сoinсidеdniсеly with thе сеlе:ausеDаrwin was thе fathеr of lf thе synthеtiсthеory of еvoluwith thе disсovеry that Darwin гs that inсludеd pеrsonal сorrеdraftsof his Ьосlks and artiсlеs. lеstroyеdЬy his suссеssor),Dar:or rеsеarсhin thе history of sсiэiеntist whсlsе importanсе was ltratеd on his voyagе on HMS writtеn soon aftеr hе rеturnеd. win's еvolutionary thought and l sеlесtion.This phasе сlf Dar_ sе natural sеlесtion wаs thе asеly with thе synthеtiс thеory of 'as oftеn rеgardеd as a puzzlе. If -l840, why did hе dеlay lеforе Ln answеr to that quеstion and' l as a man of his agе-a ViсtospесtivеЬесausе hе was thе first :romthе sо-сallеdЬlaсk Ьox' thе l in thе 1850s in prеpaгation for work was, оf сoursе, intеrruptеd rtural sеlесtiсln,and oп thе ori..Thе History of Еvolution:ssay lumе.) Thе first praсtitionеrs of as Darwin's major aсhiеvепlеnt Ovat,in сontrast' dеpiсtеd him as ;сiеnсеof his day, inсluding palеnЬгyology. This ехplainеd Darlесtion was in plaсе, Darwin's d wаs rеlativеlywеak in thе еarly g thе two dесadеs Ьеforе 1959. to arguе for transmutation Who еntalviеW of naturе that еmеrgеd tuсh аs his nеw thеory [natural еan-Baptistе]Lamarсk's'' (ospo.

This nеw viеw of Darwin as a bеnеfiсiary of ninеtееnth-сеntury morphology and еmЬryology was influеntial on sеvеral philosophеrs who, Ьеginning in thе 1980s' wеrе сonсеrnеd with thе rеlation Ьеtwееn еvolution and еmЬryolоgiсal dеvеlopmеnt (Amundson 2005; Burian 2004).It also sеt thе stаgе for Ьroadеr historiсal undеrstandings of Darwin, suсh as thosе gathеrеd Ьy historian David Kohn into thе monumеntal 1985 anthology The Dаrtuiпiаn Нeritаge, whiсh wаs dеdiсаtеd to Dov Ospovat. Vеry important was ospovat's strongly supportеd сlaim that Darwin was firmly сommittеd to thе notion of Ьiologiсal progrеss, a topiс that has Ьееn of maj o r i n t е r е s tt o h i s t o r i a n s i n r е с е n ty е a r s ( R u s е 1 9 9 6 , 2 О О 4 1R i с h a r d s 1 9 9 2 ,

2 0 0 3 2. 0 0 4 ) . BIBLIOGRAPHY Amundsсln, R. 2005. Thе Сhапgiпg Rolе of tbе Еmbrуo iп Еuсllutioпаrу Biologу: Roots of Еuo-dеuo. СamЬridgе: СаmЬridgе Univеrsity Prеss. Burian, R. М' 2004. Е1listеmсllogiсаl Pаpеrs oп Dеuelr\lmeпt, Еuolutioп, апd Gепеtiсs. СamЬridgе: СamЬridgе Univеrsity Prеss. -l Kohn, D., еd. 985. Тhе Dаrшiпiап Hеritаge. Prinсеton, Nj: Prinсеton Univеrsity Prеss. -Гhe Deuеlopmепt of Dаrtuin's Тhеorу. СаmЬridgе: Сambridgе ospоvаt' D. 1981 . Univеrsity Prеss. Riсhards, R. J. 1992..Гhе Меаniпg of Еuolutiсlп: The Мorphologiсаl Сoпstruсtioп апd ldеologiсаl Rессlпstruсtioп of Dаrшiп's Тhеorу. Сhiсago: Univеrsity of Сhiсago Prеss. 2003. The Romапtiс Ссlпсеptiсlп of Lifе: Sciепсе апd Phiklsopbу iп tЬe Аgе of Goethe. Сhiсаgo: Univеrsity of Сhiсago Prеss. 2004. Мiсhaеl Rusе,s dеsign for |iving, Jourпаl of tbе Histсlrу of Biologу З7:

2s-38.

Rusе, M. |996, Мr-lпаd to Мап: Тhе Сoпсеpt of Progrеss iп Еuolutioпаrу Biolrlgу. СamЬridgе' МА: Harvard Univеrsity Prеss. 2004. Thе romantiс сonсеption сlf Robеrt J. Riсhards. Jоurпаl of thе -R.А. Historу of BiсllogуЗ7: З-2З'

Dinosaurs:Thе modеl systеmfor еvolution Bесausеof thеir immеnsе popularity, dinсlsaursarе oftеn thе organisms that first сomе to mind whеn onе thinks aЬout animals from thе past. This, сouplеd with thе faсt that thеy wеrе disсovеrеd at thе plaсе (mid-ninеtееnth. сеntury Еngland) whеrе modеrn еvolutionary thеory took root, has lеd to thеir historiсally Ьеing usеd аs еxamplеs in еvolutionary dеbatеs.In this сontехt, dinosaurs havе playеd Ьoth positivе and nеgativе rolеs in argumеnts aЬout еvolution. Nеvеrthеlеss,dinosaurs rеmain an important сatalyst for dеvеloping a morе sсiеntifiсallylitеratе soсiеty, a rеquisitе for apprесiating and undеrstandingеvolution. Dinosaurs arе а uniquе linеagе of rеptilеs sеt apart from othеr groups Ьy thеir еrесt posturе and distinсtivе hip and hand struсturе.Thеy arе also thе most suссеssful tеrrеstrial animals to еvеr inhаbit thе еaгth. Thеir tеnurе spannеd thе pеriod from 225 to 65 million yеars аgo. Furthеrmorе' if Ьiгds

517

' 18

Diпсlsаrtrs arе in fасt a linеagе of саrnivorous dinosaurs (sееfiguге on pagе 520), thеir rеign aсtually ехtеnds anothеr 65 million yеars to thе prеsеntday, whеrе thеy dominatе thе aеrial rеalm with ovеr 9,000 spесiеs. Dеspitе thеir grеat suссеss' dinosaurs had humЬlе Ьеginnings. For instanсе' although wе tеnd to think of dinosaurs as giilnts,thе еarly forms wеrе aсtually qrritе small (50 to 100 pounds). Thеsе сагnivorous Ьipеds wеrе rathеr пlinor playеrs in Меsozoiс сommunitiеs. Ovеr timе thеy divеrsifiеd into а vаriеty of terrеstri:rlniсhеs аnd in :rll majoг linеagеs gigantisnr oссurrеd, whеrе somе spесiеs сamе to wеigh thrее or morе tons. Somе dinosaLlrs'inсluding all сarnivorous forms, wеrе Ьipеdal, whеrеas hеrЬivorous forms also inсludеd quadrapеdal taхa. On a Ьroad sсalе, dinosauгs appеar to havе Ьееn quitе sophistiсatеdin thеir bеhavioral rеpеrtoirеs.Physiologiсally thеy do not appеar to havе bеen likе living rеptilеs. Biologiсally thеy wеге perhaps moге akin to today's Ьirds and mammals, thus possiЬly ехplaining thеir grеat suссеss. Sсiеntifiс rесognition of nonavian dinosаr.rrsoссuгrеd in 1824 whеn Williаm Buсkland dеsсriЬеdМegаlosаurus (a largе сarnivorous thеropod di' nosаuг similar to Tуrаrtпosаurus reх| from Сrеtaсеous sеdimеnts in Еngland. This еvеnt was followеd by a flurry of nеw disсovеriеs of othеr dinosaurian giants tlrroughout Еuropе. With thеir oЬvious rеptilian affinitiеs' it was initially Ьеliеvеd thеsе animals wеге simply sсalеd_upvariants of living saurian groups suсh аs iguanas and сroсodilеs. It was not until 1842 tЬat this paradigr-rrwаs laid to rеst whеn rеnownеd Brirish аnatomist Sir Riсhаrd Owеn showеd that dinosаurs wеrе a uniquе rеptilian linеagе in and of thеmsеlvеs. ..fеarfully grеat Не nаmеd thеsе giants thе Dinosauria, or rеptilеs.'' owеn, who was a сrеationist at thе timе, pointеd out that attributеSof thеsе animals, suсh as еrесt posturе irnd suЬstantial fusion of thе hip vеrtеЬraе,arе not forrnd in еxtant rеptiIеs'Ьut ехist in living Ьirds irnd mammals. Hеnсе, hе сonсlr"rdеdthirt dinosaurs Wеге anatomiсally аnd physiologiсally morе advanсеd than today's rеprilеs.Hе alsо dеduсеd that living rеptilеsarе dеgеnеrgгoup' and hе quеstionеdthе plausiЬility of atе forms of a formеrly irс{virnсеd progrеssivism and transп-tutationof spесiеs. Мany sсholars Ьеliеvе that owеn сrеatеd thе Dinosauria to dеЬunk еvolutionary thеoriеs that wеrе at thе forеfront of sсiеntifiс dеЬatе at thе timе. Sеvеrаl dесadеslatеr, dinosaurs wеrе again to figuге prominеntly in еvolutionary dеЬirtеs.In 1860 quarrymеn in a limestonеquа[l.yin Solnhofеn, Gегmany' disсovеrеd а tЪilthеr from Аrсhаеoptеrух' Тhis finding showеd that Ьirds livеd at thе timе of thе dinсlsaurs.In 1861, rwo yеars aftеr Сhаrlеs Dаrwin puЬlished Оn thе Оrigin of Speсiеs' a nеw spесimen of Arсhаеoptеrух, known as thе London spесimеn, rеvеalеd thе truе, ovеrall naturе of this сrеaturе. It was undоuЬtеdly а Ьird Ьесausе it sportеd wings, fеathеrs, and a wishЬonе. Howеvеr, therе was morе to it. It possеssеdtееth, a rеptilian tail, ..missirrg and сlawеd hands. Hеrе was thе spесtaсulаr link'' (an animal intеrnrеdiаtеbеtwееn two inlportаnt groups) Darwin аnd lris followеrs nееdеd to provе thаt еvolution Was a rеality. Am:rzingly, this rеvеlation was not immеdiatеly rеalizеd. Gеrmаn palеontologistAndrеas.!Иagnеr(in 1861) and

l a г е гR i с h a r d O w е n , w l 1863), еaсh dеsсriЬеd tionary thinking, failеd с a l а v i a n а г t r i Ь u г е sS. u t Frеsh off an еXtеnsivеs this spесimеn's impoгtir t u r е s а n d p u Ь l i с a t i r l n is Аrс h ае
Dinosаurs

sееfigurеon pagе 520), thеir to thеprеsеntday, whеrе thеy lеS.

humblе Ьеginnings. For ints giants' thе еarly forms wеrе lеsесаrnivorous Ьipеds wеrе ls. ovеr timе thеy divеrsifiеd m a j o r l i n е a g е sg i g a n t i s m o с hrее or morе tons. Somе diЬ i p е d а l 'w h е r е a sh е г b i v o r o u s oad sсalе,dinosaurs appеar to .al rеpеrtoirеs.Physio1ogiсally зptilеs.Biologiсally thеy wеrе nals, thus possiЬly ехplaining urs oссuгrеd in 1824 whеn argесarnivorous thеropod di)tасеoussеdimеntsin Еngland. s с o v е r i е os f o t h е r d i n o s a u г i a n r е p t i l i . r na f f i n i t i е s ,i t w a s i n i d . u p v a r i а n t so f l i v i n g s а u г i a n not until l842 that this pаraanatomist Sir Riсhаrd Owеn l linеаgеin and of thеmsеlvеs. эarfully grеat rеptilеs.'' owеn, ut rhet аttriЬutеsof thеsе aniusion of thе hip vегtеЬraе' arе Ьirds and mammals. F{еnсе,hе and physiologiсally morе adthat living rеptilеsaге dеgеnеr1еquеstionеdthе plausiЬility of ;. Мany sсholars Ьеliеvе that ,lutionaгythеoriеs that wеrе at to figurе prоminеntly in evolu. stonе qllarry in Solnhofеn, Gегэrух. TЬts finding showеd thаt 51,two yеars aftеr Сharlеs Dar3w spесimеn of Аrсbаeopterух, truе,ovеrall naturе of this сrеаsportеd wings, fеathеrs' and a possеssеdtееth, a теptilian tail, г ..missinglink'' (аn animal in)arwinand his followеrs nееdеd zing|у, tlris rеvеlаtion was not AndrеasWagnеr (in 1861) and

latеr Riсhard owеn, who purсhasеd thе spесimеn for thе British Мusеum (in l863), еaсlr dеsсriЬеd thе spесimеn. Both' pеrhaps duе to thеir antievolutionary thinking, fаilеd to attriЬцtеany еvolutionary signifiсanсеto thе atypiсal avian attriЬutеs. SuЬsеquеntly,Thomаs Hеnry Huхlеy еntеrеd thе piсturе. Frеsh off аn еxtеnsivе study of aviаn anatomy and systеmatiсs, hе rесognizеd this spесimеrrЪimportanсе аnd usеd it аs а modеl organism in his famеd lесturеsand puЬliсationsin support of еvolution (е.g.,Huxlеy 1s6s). To this day Аrсhаеopteryх is сеlеЬratеd as onе of thе most сlеar-сut ехamplеs of an еvo. lr'rtionаrymissing link' So how do dinosaurs figurе into thе Аrсhаeoptеrух storу? AЬout thе samе timе that Arсbаeoptеry,с WaS disсovеrеd, a сhiсkеn.sizеd thеropod dinosaur known as Сompsogпаthgus was also disсovеrеd irr Gеrmany. This tiny dinosaur provеd for thе first tirrrеthat not irli dinosar.rrswеге еlеphant-sizеd,as owеn had сontеndеd. Dеvеlоpmеntal Ьiologist Сarl Gеgеnbaur in 1864 astutеly pointеd out that thе anklе struсturе of Сompsognаthgus was akin to that of Ьirds. Hе ссlrrсludеdthat it was аn аnimаl of douЬlе геlationshipboth Ьird and rеptilе. Amеriсаn paleorrtologistЕdwin Dгinkеr Сopе latеr геaсhеdthе samе сonсlusion rеgarding thе lаrgе сarnivorous tyrannosauroid Lоеlаps (= Drуptrlsаurus)'In a sеriеsof papеrs puЬlishеd from 1866 to 1869 hе pоintеd out that thе еlongatеd nесk vеrtеЬraеand light skull struсturе in Lаelаps wеrе also avian fеaturеs. Shortly thегеaftеr, Huхlеy, inspirеd Ьy Gеgеnbaur'sfindings and apparеntly unawarе of Copе's rеsеaгсh,notеd thе rеmarkaЬiе similаritiеs bеtwееn thе hips of Мegаlosаиrus and ехtant Ьirds. Using Аrсhаеopterух as а guidе, hе was aЬlе to idеntify many attriЬutеs in сommon Ьеtwееn Ьirds and dinosaцrs. By thе 1880s hе had rеaсhеd an inеsсapaЬlе сonсlusion-I.lot only аrе Ьiгds rеptilеs' thеy аrе in faсt living thеropod dinosaurs. Аrсbаeoptеrуr is simply a fеathеrеddinosaur. This viеw of avian anсеstry is now almost univеrsally aссеptеd among palеontologists.Ironiсally, dеspitе Ьеing nеaгly a сеntury and а half old' it has оnly rесеrrсlyЬееn аdoptеd on a Ьroad sсalе. By thе turn of thе ninеtееnth сеntury' palеontologists instеad favorеd thе сompеting thеory of stеm rеp. tilеs from whiсh thе mаjor сladеs of aгсhosaurian rеptilеs (dinosаur rеlativеs)' сroсodilians, hеrЬivorous ornithisсhian dinosaurs, ptеrosaurs (flying rеptilеs),saurisсhian dinosaurs (thеropods and long-neсked hеrЬivorеs),and Ьirds indеpеndеntly rosе. It was fеlt thаt thе сommon fеаtures sharеd Ьy Ьirds аnd dinosаurs stеmmеd fгom а morе anсiеnt сommon аnсеstor than within thеropods thеmsеlvеs. In thе 1960s, Huхlеy's сhargе was rеnеwеd whеn Amеriсan palеontologist John ostrom disсovеrеd wеll-prеsеrvеdspесimеnsof Dеinonусhus, a mеm. Ьеr of thе Dгomaеosauria (small to rnеdium-sizеd, agilе саrnivoroцs dinosaurs with siсklе-likе сlaws on thеiг fееt). ostrom and othеrs idеntifiеd nеarly 200 dinosaurian attriЬutеs sharеd Ьеtwееn Ьirds and dromaеosaurs. inсluding nцmеrous fusеd sасral vеrtеЬrае,hollow lеg Ьonеs, and long forе. arms (sее figurе on pagе 520). Furthеrmоrе, сladistiс analysеs-a mеthodology whеrеЬy sharеd-dеrivеd(еvolutionaгilyсhangеd)сharaсtеristiсsarе usеd to еstаЬlishrеlationships-showеd thаt thе gеnеsisof Ьiгds сamе from within

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Diпosаurs

Сomparison Ьеtwееnthе fiгst Ьtrd, Arсbаeсlpterух,and thе dromaеosaurian dinosaur, Vеlocirаptсlr.Notе thе sharеd fеaturеsЬеtwееnthе Ьird (lеft) and tЬe nonavian dinosauг kisht)' whiсh inсludе upright posturе' soсkеtеdсarnivorous tееth' fеathеrs'thrее or morе fusеd hip vеrtеЬraе,thrее main toеs and fingеrs'аn s.shapеdnесk, ехtrеmеly long forеlimЬs,an еlongatеdand rеtrovеrtеdpuЬis (hip еlongatеd Ьonе)with a Ьoot shape'a stiffеnеdtаil, а сurvеdfеmur (thighЬonе), a pеrforatеaсеtaЬulaе(a tunnеl mеtatarsals(foot Ьonеs),сlaviсlеs(wishЬonеs), through thе hip Ьonеs Ьеtwееnwhеrе thе thighЬonеsattaсh),аn аntorЬital fеnеstra(a holе in thе skull in front ofthе еyе soсkеt),and hсlllowbonеs,just to namе a fеw.

thе Dinosauria. Statistiсallyit is ехtrеmеly unlikеly that Ьirds сould havе dеsсеndеd from any othеr group of animals. Today, aссеptanсеof this thеory is almost univеrsal. Nеvеrthеlеss,during thе last 15 yеars a fеw holdouts (gеnеrally avian palеontologists and ornithologists) сlung to thе notion that avian anсеstry still might Ье found in somе еarliеr stеm rеptilе. Thеy сontеndеd that similaritiеs Ьеtwееn dinosaurs and Ьirds might somеhow rеflесt indеpеndеnt adаptations to similar еnvironmеntal sеlесtivеforсеs. Thе сruх of thеir dissеnsionWas thе aЬsеnсе in dinosaurs of sеvеral сritiсal dеfining attriЬutеs of Ьirds. Thеsе inсludеd thе avian wishЬonе (fusеd сlaviсlеs or furсulaе) and fеathеrs,аs wеll as thе faсt that thе smallеst dromaеosaurs' thought to Ье thе anсеstors to Ьirds, wеrе grеatеr than 25 pounds in mass and sееmеd unlikеly сandidatеs for giving risе to thе muсh smallеr Аrchаeoptеryх. Spurnеd Ьy thеir соntеntions, palеontologists еn massе foсusеd on thе study of thеsе fеaturеs.In quiсk suссеssion, еaсh was rеvеaled in dinosaurs. Rеехamination of thеropods showеd that furсulaе еxistеd, Ьut thеy had not Ьееn prеviously rесognizеd. Fеathеrs Wеrе found in nonvolant dinosaurs from China. PrеsumaЬly thе fеathеrswеrе for display and/or thеrmorеgulation.onе spесimеn,a pur-

portеd glidеr, appеars tl Мiсrсlrаptor, thе smal Ьasal dromaеosaur to Ь еvolution of Ьirds. Ad< s a u г i a n a n с е s t r yf o r Ь i l nonavian dinosaurs is r likе Ьirds, and that ехt nosaur skеlеtons. \Vith has all Ьut еndеd. Dinol ologiсal Ьordеr sеpara nosaurs rulеd, from mo astеroid or othеr сataс outsidе today. Dinosaurs havе plаyt еvolutionаry thеory Ьy 1 port of еvolution-Аrсl gеnеsis.But do thеsеan ary undеrstanding in th amplеs of human and sеrvе as a valuaЬlе vеhi еntifiс mеthod and at th сhаeopterух story is n( dеtail, although arguaЬ Ьratе. In faсt it is just o nosaurs rеaсhеd еlеphа for vаriant dеvеlopmеn land situations.'Wе knс dеntal Ьattеriеs (thе еv tion with floral сhangеs сhangеs, сontinеntal dr at thе timе of an astеro world. Thе aforеmеntionеd еraЬlе attеntion in th Through dinosaurs thе Ьroadly promoting еv guaЬly onе of thе most influеnсе in promoting еvolution gain broadеr tеn than not our сhildrt and thеrе is no Ьеttеr young' сurious, opеn m arе told will bе Ьеttег. arе told is a rеality or : important sсiеntifiс pu

Diпosаurs

rух, and thе dromaеosаurlan :s Ьеtwееn thе Ьird (left) and tЬe h t p o s г u r е .s о с k е t е dс a г n i v o r о u s tе' thIее main toеs and fingеrs, an lngatеd and rеtrovеrtеd puЬis (hip ,еd fеmur (thighЬonе)' еlongatеd a pеrforatеaсеtаЬulaе (a tunnеl rЬonеsattaсh),аn antоrЬital ; o с k е r )а' n d h о l l o w Ь o n е s ' j u s t t о

rnlikеlythat Ьirds сould hаvе dе;t univеrsal.Nеvеrthеlеss,during ly avian palеontologists and or_ t anсеstrystill might Ье found in l that similaritiеs bеtwееn dinolеpеndеntadaptations to similar thеir dissеnsionwas thе aЬsеnсе :riЬutеsof Ьirds. Thеsе inсludеd ulaе) and fеathеrs,as wеll as thе ght to Ье thе anсеstors to birds' l sееmеdunlikеly сandidatеs for )pterух. Spurnеd Ьy thеir сonon thе study of thеsе fеaturеs. In r dinosauгs.Rеехаmination of thеy had nоt Ьееn prеviously rесlinosaursfrom Сhina. PrеsumaЬly rrеgulation.onе spесimеn, a рur-

portеd glidеr, appеars to havе had wings. Finally, thеrе was thе disсovеry of Мiсrсlrаptor, thе smallеst known dinosaur-Аrchаeopterух-sized and a Ьasal dromaеosaur to Ьoot. Сlеarly miniaturization had oссurrеd Ьеforе thе еvolution of Ьirds. Additional findings solidifying thе argumеnt for dinosaurian anсеstry for Ьirds inсludе thе disсovеry that еgg miсrostruсturе of nсlnaviandinosaurs is matсhеd in birds, that thеropods Ьroodеd thеir еggs I i k е Ь i r d s , a n d t h a t е x t е n s i v еa v i а n г е s p i r а r o г ya i r s a с s y s t е m sе x i s t i n d i nosaur skеlеtons. !(/ith thеsе latеst findings, thе dеЬatе ovеr avian anсеstry has all but еndеd. Dinosaurs did not go ехtinсt at thе K-Т Ьoundary (thе gеologiсal bordеr sеparating sеdimеnts from thе Меsozoiс Еra, whеn thе dinosaurs rulеd, from morе modеrn Сеnozoiс Еra sеdimеnts)'dеstroyеd by an astеroid or othеr сataсlysmiс сhangе. Thеy in faсt rеsidе fluttеring about outsidе today. Dinosaцrs havе playеd an important rolе in thе dеvеlopmеnt of modеrn еvolutionary thеory Ьy providing onе of thе most сеlеbratеd ехamplеs in support of еvolution-Аrсhаеopterуx and thе еvolutionary stagеs lеading to its gеnеsis.But do thеsе animals havе anything to offеr for pгomoting еvolutionary undеrstanding in thе futurе? I Ьеliеvе thе answеr is yеs. Alоng with еxamplеs of human and еquinе (horsе) еvolution, studiеs of dinosaurs will sеrvе as a valuaЬlе vеhiсlе Ьy whiсh thе puЬliс сan Ьесomе vеrsеd in the sсiеntifiс mеthod and at thе samе timе grasp thе workings of еvolution. Thе Аrсbаeopterух story is not thе only еxample that is workеd out in intriсatе dеtail, although arguaЬly it has sеen morе еxamination than any fossil vеrtеЬratе. In faсt it is just onе of many. Sсiеntists now know how many timеs dinosaurs rеaсhеd еlеphantinе proportions, how thеy did it through sеlесtion for variant dеvеlopmеntal trajесtoriеs, and how thеy Ьесamе dwarfеd in is.sИе land sitцations. know how thеy divеrsifiеd with kеy innovations suсh as dеntal Ьattеriеs (thе еvolution of сhеwing using multiplе tееth) in сonjunсtion with floral сhangеs. And wе havе a good undеrstanding of how сlimatiс сhangеs' сontinеntal drift, and thе dеmisе of nonavian dinosaurs-plausiЬly at thе timе of an astеroid impaсt-lеd to еvolutionаry сhangе that shapеd thе world. Thе aforеmеntionеd studiеs of еvolutionary еvеnts havе rесеivеd сonsid. еraЬlе attеntion in thе worldwidе mеdia and hеnсе in thе publiс еyе. Through dinosaurs thе еvolutionary mеssagе is gеtting through. As suсh, for Ьroadiy promoting еvoiutionary undеrstanding' dinosaur rеsearсh is arguaЬly onе of thе most important fiеlds today. Нowеvеr, dinosaur rеsеarсh's influеnсе in promoting sсiеntifiс undеrstanding and its potеntial for hеlping еvolution gain Ьroadеr aссеptanсе сould Ье сonsidеraЬly grеatеr. }yIorе oftеn thаn not our сhildrеn's first introduсtion to sсiеnсе is through dinosaurs, and thеrе is no Ьеttеr opportunity to tеaсh thе sсiеntifiс mеthod than to young' сurious, opеn minds. Thosе who ask for data in support of what thеy arе told will Ье Ьеttеr еquippеd to judgе for thеmsеlvеs whеthеr what thеy arе told is a rеality or not. It is for this rеason that dinosaur rеsеarсh is an important sсiеntifiс pursuit, onе that сan faсilitatе sсiеntifiс litеraсy and

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Dobzhаnshу providе thе rеquisitе Ьaсkground for undеrstanding and iudging thе lеgitimaсy of aЬstraсt сonсеpts suсh as еvolution. Tеaсhing sсienсе at an еarly agе should Ье of primary importanсе for sсiеntists intеrеstеd in promoгing a morе sсiеntifiс litеratе soсiеty. Dinosaurs сan providе thе modеl ехamplеs to makе this a rеality. B|вLIoGRAPHY Сopе, Е. D. \867 . An ассоuntof еxtinсt rеptilеsthat apрroaсhЬird,s.Proceеdiпgsof thе Аcаdemу of Nаturаl Sсieпcesof Philаdelphiа19: 234_2З5. Darwin, с. 1859. on the origin of Speсles.London:John Murray. for сhildrеn.]http://www ЕnсhantеdLеarning.Zoom Dinosaurs.[.!Иеbsitе .еnсhantеdlеarning.сom/suЬi есts/dinosaurs/. Aпаtomiеder GеgеnЬaur,С. 1864. Untersuсhипgeп 7ur uergleichеndеп ,1., Wirbеlthiеrе.Уo|. Саrpus und Таrsus.Lеipzig:!7ilhеlm Еngеlmann. Huxlеy,T. H. 1868.On thе аnimalswhiсh arе mostnеarlyintеrmеdiatе bеtwееn Ьirdsаnd rеptilеs.GeologiсаlМаgаziпе5:357_365. ostrom, J. H' 1969. A nеw thеropoddinosaurfrom thе Lowеr Сrеtaсеousof ]Vlontana.Postillа 128: T-17. I975 . TЬе origin of Ьirds.Аппuаl Reuiеt,c' of Еаrth апd PlапеtаrуSсiеnсеs3: 55-77 . Owеn, R. 1853. on theArсhаeopterухo| Von Mеyеr, with a dеsсriptionof thе fossil rеmainsof a long-tailеdspесiеsfrom thе lithogrаphiсstonеof Solnhofеn. PhilosophicаlTrапsаctionsof thе Roуаl Soсietуof Loпdoп |53: ЗЗ47. Univеrsityo{ California N4usеumof Palеontology.www.uсmp.Ьеrkеlеy.еdu. .Wagnеr, Rеptil aus J. A. 1861. UЬеr еin nеus,angеЬliсhmit Vogеlfеdеrnvеrsеhеnеs dеm SolnhofеnеrlithоgraphisсhеnSсhiеfеr.BауеrisсhеАkаdеmiеder 'Wissепsсhаftеи -G.М'Е. (Мuniсh) 2z 146-154.

Dobzhansky'Thеodosius(|900-Т975) Thеodosius DoЬzhansky is pеrhaps most famous for thе slogan, ..Nothing in Ьiology makеs sеnsе еxсеpt in thе light of еvolution,' (DoЬzhanskу 1973|, whiсh is еndlеssly invokеd Ьy еvolutionists in thеir Ьattlеs with сrеationists. But that is only half thе Ьattlе that DoЬzhansky wаgеd on Ьеhalf of thе importanсе of еvolutionary thinking. Hе had two targеts in mind: сrеationists and thosе would-Ье еvolutionists who naivеly supposе that molесular Ьiology is thе kеy to lifе whеn in faсt nothing, not еvеn thе proсеssеs of molесular biology' сan Ье undеrstood ехсеpt in thе light of еvolution. Ironiсаlly, DoЬzhansky himsеlf was oЬsеssеdin a rеligious or at lеast a moralistiс way with thе ..mеaning'' of еvеrything, еvolution inсludеd (Bеatty 1'987a, 1'987Ь1 Rusе 2001; van dеr Мeer 2007)' Еrnst Мayr (196з) may havе bеliеvеd that еvolutionary Ьiology providеd thе ultimatе ехplanations of lifе, whilе molесular Ьiologiсal explanations arе at Ьеst proximatе' Ьut for DoЬzhansky, thе ultimatе understanding of lifе was dееpеr still than еvolution (sееthе disсussion latеr in this еntry). To thosе familiar with his work, DoЬzhansky is known not just as a flag Ьеarеr for еvolutionary thinking, Ьut in partiсular for his сontriЬutions to population gеnеtiсs.Hе did as muсh oг morе than anyonе еlsе to еstаЬlish

that fiеld and sеt its еarl1 Gепetiсs апd the Оrigm Was that thе study of gег duсiЬlе to gеnеtiсspеr sс thе еntirеty of еvolution. gard hе stipulatеd Ьy dс gеnе frеquеnсiеs'' (DoЬz Thе main proЬlеm of ..parado Gепеtics, is thе to havе variation prеsеn othеr hand, thе partiсulа arе vеry likеly maladapt ..Еvolutt matiс fashion, lеssly dеar priсе of сont unfavorablе mutations'' D o Ь z h а n s k y . so w n i n s variation in natural (nor in Russia. At that timе bееtlеs,Ьut it was his stt f|у, Drosrlphilа, that wс dеrtakеn in thе 1930s, working with thе Drosa DoЬzhansky,s еarly Wor 1981). Drosophilа at first sе thеrе sееmеd to Ье no int gan's ехсitеmеnt at finalL i n h е r i t а n с ес o u l d Ь е s t t grеatеrnumЬеrs in his la] ations wеrе artifaсts. D/ traspесifiс variation' and еvolution. In trying tо п wild Drosop hilа' DoЬzhl who proposеd that most aЬlе diffеrеnсеs only wh oссur morе oftеn in laЬ< сasе thеrе is signifiсanti way, natllral population DoЬzhansky, originаl W a y t o o Ь s е r v ео t h е r w i s сrosсopе on variations l that involvе diffеrеnсеs gеnе diffеrеnсеs as Wеll. f o г е v o l u t i o n a r yс h а n g е DoЬzhansky at first part to ехp|аin rhis variаtit

Dolэzhапskу сandingand iudging tlrе lеgiti. T е a с h i n gs с i е n с еa t a n е a г l y l t i s t si n t е r е s t е di n p г o m o t i n g a providеthе modеl ехamplеs to

rаt approaсh Ьirds. Proсеediпgs of hiа 79 234_235. rn: John Мurray. lr сhildrеn.] http://www hеп,1епАпаtomiе dеr 'zig:Wilhеlm Еr.rgеlrnann. lst nearly intеrmеdi:rtеЬеtwееn /-5b).

,m thе Lowеr Сrеtaсе
/Jl ..Nothing in rous for thе slogаn, е v o l u t i o n ' '( D o Ь z Ь a n s k у I 9 7 З ) , t n t h е i r Ь a t t l е sw i t h с г е a t i o n i s t s . rsky wagеd on Ьеhalf of thе im] W оt а r g е t si n m i n d : с r е a t i o n i s t s зly supposеthat molесular Ьiolot еvеnthе proсеssеsof molесuhе light of еvolution. Ironiсally, ,iousor at lеast a moralistiс way Linсludеd(Bеatty 1,987a,1987Ь; ,r (1963\ may havе Ьеliеvеd that :хplanationsof lifе, whilе molес_ кintаtе,Ьut for DoЬzhansky, thе ill than еvolution (sееthе disсusLnskyis known not just as a flag t r t i с u l a rf o г h i s с o n t r i Ь ш t i o n st o )rе than anyonе еlsе to еstaЬlish

that fiеld and sеt its еarly agеnda, еspесiallythrough his influеntiаl tехtЬook Gеnetics аnd tbе Оrigin of Spесiеs.onе of thе гесurrеnt thеmеs of Gеnetics wаs that thе study of gеnе frеquеnсy сhangesis an autonomous fiеld, not rеduсiblе to gеnеtiсspеr sе (i.е.,thе gеnеtiсsof individuals). And its domain is thе еntirеty of еvolution. What Dоbzhаnsky сould not provе in thе lattеr rе. gard hе stipulatеd Ьy dеfinition: ..еvolution is [no rrrоrеthаn] a сhangе in gеnе frеquеnсiеs''(DoЬzhansky 19З7, l t; sее also suЬsеquеntеditions). Thе main proЬlеm of population gеnеtiсs' as DoЬzhansky еl:rl.loratеdin Genetiсs, is thе..paradoх of viaЬiliry.'' On thе onе hand, еaсh spесiеsnееds to hаvе vаriation prеsеntin ordеr to adapt to еnvironmеntal сhangеs.On thе otlrеr hand' thе partiсular vаriations that might pгovе adaptivе in thе futurе аrе vеry likеly mаlас1aptivеat prеsеnt.As hе сonсludеd in his typiсally draпatiс fashion, ..Еvсrlutionaryplastiсity сan Ье puгсhasеd onlу at thе ruthlеssly dеar priсе of сontinuously sасrifiсing somе individuals to dеath from unfavoraЬlеmutations'' (DoЬzhanskу 79З7, 126-127). DoЬzhansky's own insights into thе paradox wеrе Ьasеd on his studiеs of variation in naturаl (nonlаЬorаtory) populations, whiсh Ьеgan in thе l920s in Russia. At thаt tinrе hе wаs studying intraspесifiс variation in ladуЬird bееtlеs,Ьut it was his studiеs of virriation in naturаl populations of thе fruit f|у, Drosophilа, tЬat would provе most influеntial. Thеsе studiеs Wеrе un. dеrtakеn in thе 1930s, aftеr hе had movеd to thе Unitеd Statеs аnd was working with thе Drсlsсlpbilа gеnеtiсist Thomas Нunt Мorgan (сonсеrning DoЬzhаnsky's еаrly w
r98r).

Drosophilа at first sееmеd vеry diffеrеnt from ladyЬugs. Phеnotypiсally, thеrе sееmеd to Ье no intraspесifiс variаtion at all. onе nееd only rесall Morgan's ехсitеmеntat finally disсovеringan oЬsеrvaЬlеmutаnt whosе pаttеrn of inhеritanсе сould Ье studiеd. SuЬsеquеntly,variations wеrе found it-tеvеr grеatеrnumЬеrs in his l:rЬorаtory.But it was ЬеliеvеdЬy rrranythaс thеsеvariations wеrе artifасts. Drosophilа in thе wild sееmеdto havе littlе if аny in. traspесifiс variation, and hеnсе pеrplехingly littlе пrаrrеrialfor futurе adaptivе еvolution. In trying to makе sеnsе of thе diffеrеnсе Ьеtwееn laЬoratory and wi|d Drosophilа' DoЬzhansky followеd thе suggеstiсlnof Sеrgеi Сhеtvеrikov, who proposеd that пrost mutatioпs wеrе rесеssivеand rvor-rldгеsult in oЬsеrvaЬlе differеnсеsoгrly whеn dorrЬlеd up in thе homozygous statе.Tlris would oссur morе oftеn in laЬoratory stoсks than in natllrе' bесаusе in thе formеr саsе thеrе is signifiсantly morе inЬrееding than in wild populations. In this way, natural populatiоns sоak up vaгiations likе a spongе. DoЬzhаnsky, oгiginally in сollaЬoratiсln with Alfrеd Sturtеvanс' found a Wаy to oЬsеrvе othеrwisе hiddеn variatiorriл Dros
52з

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Dobzbаnskу insignifiсant and that thеir frеquеnсiеs wеrе drifting randomly. This might lеad to a rеduсtion in variation within еaсh population of a spесiеs' Ьut would lеad to an inсrеasеin variation Ьеtwееnpopulations and hеnсе within thе spесiеs. DoЬzhansky was quitе surprisеd, thеn, to find еvidеnсе that thе invеrsion diffеrеnсеs wеrе adaptivеly signifiсant aftеr all, lеading him to ехplorе a rangе of variation-maintaining forms of natural sеleсtion. Hе finally sеttlеd on thе idеa that hеtеrozygotеs arе adaptivеly supеrior to homozygotеs Ьесаusе having two gеnеs for a ttalt, instеad of two сopiеs of thе samе gеnе, allows morе adaptaЬility at thе individual lеvеl. Sеlесtionfor adaptaЬility at thе individual lеvеl in turn prеsеrvеsеvolutionary adaptaЬility at thе spесiеs lеvеl. ..Ьalanсе'' DoЬzhansky's aссount сamе to Ье known as thе thеory of еvolution. His main dеtraсtor was Неrmann Mullеr' whosе viеw of еvolution ..сlassiсal'' (old-fashionеd) was duЬЬеd Ьy DoЬzhansky thе thеory (on thе сlassiсal/Ьalanсесontrovеrsy, sее Bеatty 1987ь [and othеr еssayson that issuе] and Lеwontin 1974). Aссording to Mullеr, thеrе was no paradoх of viaЬility. Thе vast majority of mutations arе dеtrimеntal for thе individuals in whiсh thеy oссur, and аlso for thе spесiеs in whiсh thеy aссumulatе. Thеrе was, in Мullеr's opinion, only onе spесiеs-humans-in whiсh mutations aссumulatе to any grеat ехtеnt. Through thе amеnitiеs of сivilization, wе humans havе managеd to еsсapе natural sеlесtion,to our ultimatе dеtrimеnt. Only through a сonsсious еugеniсs program сan Wе now suссеssfully rеvеrsе thе rising tidе of dеlеtеriousmutations. DoЬzhansky, for his part, сritiсizеd ..thе еugеniсal Jеrеmiahs'' who ovеrlook thе importanсе of еvolutionary plastiсity and who sееm unawarе that natural populations of many spесiеs possеssсonsidеraЬlеrеsеrvеsof variаtion (DoЬzhanskу 1'9З7, |26). Dobzhansky and Мullеr wеrе also at thе сеntеr of сontrovеrsiеs from thе 1950s through thе ear|у |970s сonсеrning thе impaсt of radiation-induсеd mutation from atomiс Wеapons tеsts. (Both mеn rесеivеd сonsidеraЬlе funding from thе Atomiс Еnеrgy Сommission during this pеriod.) Adding yеt morе mutations to thе human spесiеs was straightforwardly nеgativе from Мullеr's point of viеw, but lеss so from DoЬzhansky's viеwpoint. Intеrеst. ingly' DoЬzhansky was strongly opposеd to thе tеsting and usе of atomiс Wеapons' whilе thе onсе pro-Soviеt Мullеr Ьеliеvеdthat, up to a point, suсh Wеapons had an important rolе tсl play in thе с
As muсh as hе сlaim dееply уtzz\ed and un proсееdеd. Hе had four t h е p r е s е r v a t i o no f v а г i that rесonсilеd thе gоoс grеatеr fitnеss of hеtеro tinuе to Ье Ьorn in еaсh undеrstood this situatlo frее will, whiсh givеs us Pеrhaps. But hе also еx1 nаturе'' thаt so many ir of thе group (DoЬzhan

1ОО_1'22;van dеr Мееr DoЬzhansky drеw p sourсеs in his invеstigat was a major rеason for t tеxt. DoЬzhansky's und intraspесifiс variation a dеr Mееr 2007), аlthоug and many of thе samе с also Ьееn raisеd in thе l in сonvеrsations with D. B|вLIoGRAPHY

Adams, M. B., еd. 1994.. PrinсеtonUnivеrsityI Bеаtty,l. 1987a. DoЬzha biology.In L. Kriigеr СamЬridgе,МA: Har |987ь..!Иеighint Jourпаl of thе Нistorу 1994.DoЬzhansk signifiсanсе of gеnег ThеodosiusDobzhап DoЬzhansky,T. 1'937.Cе UnivеrsityPrеss. 1.962,MаnhiпdЕl Нavеn' СT: Yаlе Unrv l 9 7 З . N o t h i n цi r r Аmеriсап Biologу Tе Dunn' L. С., and T. DoЬz Pеnguin. Lеwontin'R' С, 1974,Тh Harvard UnivеrsityPl I9 8 l . l n r r о d u с t Lеwontinеt al.,еds.' N е w Y o r k :С o l u m h i Lеwontin,R. С. еt al.,еds I-XLIII. Nеw York: ( N4ayr,Е. 1963.Сausеаnd

Dobzhапskу drifting randomly. T'his might r population of a spесiеs, Ьut l populationsand hеnсе within i n d е v i d е n с еr h a r t h с i n v е г s i o n , lеading him to еxpl
As muсh as hе сlaimеd to undеrstand еvolution, DoЬzhansky rеmainеd dееply puzz|ed and unсomfortaЬlе aЬout thе mеans Ьy whiсh evolution proсееdеd.Hе had found a Way to rесonсilе thе sеlесtion of thе fittеst with thе prеsеrvation of vaгiation for futurе adaptivе еvolution, Ьut not in а way that rесonсilеd thе good of thе spесiеswith thе wеlfarе of its mеmЬегs.Thе grеatеr fitnеss оf hеtеrozygotеsmеans that lеssеr-fithomozygotеs will сontinuе to Ье Ьorn in еaсh gеnеration.It hаs Ьееn suggеstеdthat DoЬzhansky undеrstood this situation rеligiously, as a nесеssaryеvil-along thе linеs of frее will, whiсh givеs us moral frееdom' Ьut at thе сost of many sad сhoiсеs. Pеrhaps. But hе also ехpliсitly rеgardеd it as an ..unplеasingimpеrfесtion of naturе'' that so many individuals should suffеr suсh ..misеry'' for thе good of thе group (DoЬzhanskу19З7,1271DoЬzЬanskу 1962, З35; Rusе 2001, |00_\221van dеr Меег 2007). DoЬzhansky drеw produсtivеly on his Russian hеritagе and Russian sourсеs in his irrvеstigationsand ехplanations of intraspесifiс variation. This was a major rеason for thе originality of Gепеtics in an Anglo-Amеriсan сontеxt. Dobzhаnsky's undеrstanding of thе rеligious/moralistiс signifiсanсе of intraspесifiс variation also rеflесtеd his Russian hеritagе (sее еspесiаlly van dеr Mееr 2007), аlthough this influеnсе has Ьееn morе diffiсult to rесonstruсt, and many of thе sanrе сonсеrns-suсh as thе еvils of natural sеlесtiсln-had also Ьееrrraisеd in thе Anglo_Amеriсan сontеХt (..g., Ьy thе athеist Мorgan, in сonvеrsationswith DoЬzhansky; Bе21ttу|994,207 and notе 3). в|BLIoGRAPHY Adams,M. B., еd. 1994. Thе Еuсllutioпof ThеodosiиsDobzhапskу.Prinсеtоn,NJ: PrinсеtonUnivегsityPrеss. Bеatty,J. 1987a.DoЬzhanskyand drift:Faсts,valuеsand сhanсеin еvolution;rry Ьiology.In L. Kriigеr еt al., еds.,The ProЬаbilistiсRеuolutk-lп,уolr.2. Сambridgе,МA: НaгvаrrdUnivеrsityPrеss' 1987ь.!7еighingthе гisks:Stаlеmаtе in thе сlаssiсаl/Ьalanсе сontrovегsy' lourпаl of thе Нistorу of Biologу 2О:289_З|9. \994. DoЬzhanskyand thе Ьiologvof dеmoсraсy:Thе moral and politiсal signifiсanсеof gеnеtiсvariation.In М. B. Adаms, ed.,Tbe Еuolutioп of TheodosiusDobzhапskу'Prinсеton,NJ: PrinсеtonUnivеrsityPrеss. DoЬzhansky,т. 1937, Geпеticsапd the origiп of Spесles.Nеw York: СolumЬia UnivеrsityPrеss. |962. Маnkiпtl Еuoluiпg:Thе Еuolution сlf the Нumап Speсles.Nеw Havеn' СT: Yаlе UrrivеrsityPrеss. 1973.Nothingin Ьiologymakеssеnsеехсеptill thе lightof еvсllution. АпtеriсапB iolсlgуTrасhеrЗ5 : 1 5-129. Dunn,L. С., arrdT. DoЬzhаnskу'1946.Hеrеditу,Rасе,апd Soсiet1'. Nеw Yoгk: Pеnguin. Lеwontin,R. с. 1974. Тhе Gепetiс Bаsisof ЕuolutirlпаrуСhапge.CamЬridgе,MA: Harvard UnivеrsityPrеss. 1981.Introduсtion: Thе sсiеntifiсwork of ThеоdosiusDoЬzhansky.In R. С. Lеwontinеt al., еds.,Dobzhапskу'sGeпеtiсsof Nаturаl PopulаtioпsI-XLIII. Nеw York: ColuпrЬiaUnivеrsityPrеss. Lеwontin,R. C. еt al.' еds. "|981. Dobzhаnskу'sСепеtiсsof Nаturаl Popиlаtions LXLLI]. Nеw York: СolrrmЬiaUnivегsityPгеss. Мayr, Е. l963. Сirusеand еitЪсtin Ьiologv.Sсiепсе134:1501_1506.

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Drosophila .vи. Provinе, B. 1981.origins of thе Gеnеtiсsof Natural Populationssеriеs.ln R. С. Lеwontin еt al., еds.,Dobzhапskу'sGепеtiсsof Nаturаl PopиlаtionsI_XLПI. Nеw York: Сolumbia UnivеrsityPrеss. Rusе, М. 2ОО,|.Муsterу of Муstеriеs:Is Еuolutioп а SсlсiаlСoпstruсtioп? Сambridgе,МA: Harvard UnivеrsityPrеss. ..Nothingin еvolutionmakеssеnsе van dеr Mееr,J. 2007.ThеodosiusDoЬzhar-rsky: еxсеptin thе light of rеligion.''In N. Rupkе, ed,,Еmiпеnt Liuеs iп Tt,uепtiеthСепturу Sсiепcе апd Religion. Frankfurt: Pеtеr Lang.

-1.8.

DrosophiIа Drosophilа is a gеnus of fliеs in thе family Drosophilidaе that arе widеly usеd for еvolutionary rеsеarсh. Thе origin of this rеsеarсh liеs in Thomas Hunt Мorgan's NoЬel Prizе-winning work on inhеritancе in Drosopbilа mеlапogаstеr (sее figurе) starting around 1908. Мorgan's intеllесtual dеsсеndants havе ехpandеd thе sсopе of work on D. melаnogаstеr from gеnеtiсs into virtually еvеry aspесt of Ьiology, turning it into onе of thе most usеful modеl organisms. Еvolutionary rеsеarсh has Ьееn a roЬust part of this tradition from thе bеginning. Сuгrеntly' thе сomЬination of thе еasе and spееd with whiсh many spесiеs сan Ье rеarеd in thе laЬoratory and thе ехtеnsivе Ьaсkground knowlеdgе of gеnеtiсsand dеvеlopmеnt makе thеm usеful in addrеssing a widе vаriеty of quеstions in еvolutionary gеnеtiсs. Drosophilа adults arе usually only a fеw millimеtеrs long' with prominеnt rеd to Ьrown еyеs, and сomplех ехtеrnal moгphology that has rеmainеd fairly сonsеrvativе ovеr еvolutionary timе. Drosophilа sЬow holomеtaЬolous dеvеlopmеnt, undеrgoing a сomplеtе transformation from thе fееding larvaе to the adult form during a pupal stage. Thеy arе сommonly сallеd fruit fliеs, although most spесiеs fееd on miсroorganisms that inhaЬit rotting plant ma. tеrial. Thе gеnus Drosopbilа сurrently inсludеs Ьеtwееn 1,150 and 1,500 spесiеs, dеpеnding on whiсh groups arе inсludеd in thе gеnus, and has a worldwidе distriЬution. Phylogеnеtiс rеsеarсh has сlеarly shown that thе genus is paraphylеtiс, mеaning that othеr gеnеra arе morе сlosеly rеlatеd to somе of t'Ьe Drosophilа than thеy arе to othеr groups. In thе Ьroad sеnsе, thеn, Drosophilа sЬou|d inсludе many other gеnеra' inсluding thе spесiеsriсЬ Sсаptomуzа (approximаtеly 260 spесiеs), Hirtodrosopbilа (approхimatеly 150 spесiеs), and Муcodrosophilа (approхimatеly 120 spесiеs). N{olесular еvidеnсе sttggеststhat thе gеnus is at lеast 50 million yеars old, a сonсlusion supportеd Ьy drosophilid spесimеnsin ambеr that arе around this agе. Around 1910, Мorgan disсovеrеd a singlе D. melапсlgаsler with whitе еyеs' thе inheritanсе of whiсh turnеd out to Ье sех linkеd. This simplе obsеrvation inspirеd Morgan and his laЬoratory studеntsto isolate othеf mutants, with whiсh thеy wеrе aЬlе to сonfirm thе hypothеsis that gеnеs rеsidе on сhromosomеs. In thosе yеars, Morgan's tiny (16 fееt Ьу 24 feet)..fly room'' at СolumЬia Univеrsity had еight dеsks; thrее wеrе oссupiеd Ьy Сolumbia

Drosophilа mеlапogаs Thе way in whiсh it wl \994.

undеrgraduatеs Alfrе N4ullеr, who all playr Morgan, Bridgеs, anс whеn thеy all movеd whеrе thеy rеmainеd

Drosophila aturalPopulations sеriеs.In R. С. of NаturаI Populаtioпs I-хLlll. п а SoсiаI Сoпstruсtioп? .Nothing in

еvоlution mаkеs sеnsе еd.,Еlпiпeпt Liuеs iп Ttuentietb-1.8. :r Lang.

Drosophilidaе that arе widеly of this rеsеаrсh liеs in Thomas : on inhеritanсе in Drosophilа l 1908. Morgan's intеllесtual rork on D, mеlапogаstеr from ogy, turning it into onе of thе гy rеsеarсh has Ьееn a roЬust СurrеntIy, thе сomЬination of еs сan Ье rеarеd in thе laboragе of gеnetiсsand dеvеlopmеnt эty of quеstions in еvolutionary r i l l i m е t е r lso n g , w i t h p r o m i n е n t morphology that has rеmainеd r osophilа show holomеtaЬolоus rmation from thе fееding larvaе .arе сommonly сallеd fruit fliеs, ns that inhabit rotting plant mau d е s Ь е t w е е n1 , 1 5 0 a n d 1 , 5 0 0 сludеd in thе gеnus, and has а гсh has сlеarly shown that thе |nеraarе morе сlosеly rеlatеd to 'hеr groups. In thе broad sеnsе, )r gеnеra' inсluding the spесiеsies\, Hirtodrosopbilа (approxir (approximatelу 720 spесiеs). is at lеast 50 million yеars old, imеns in amЬеr that arе around 31eD. melапogаster with whitе Ье sех linkеd. This simplе oЬsеrtudеntsto isolatе othеr mutants' hypothеsisthat gеnеs rеsidе on ' (\6 feetЬу 24 feet) ..fly room'' rее wеrе oссupiеd Ьy СolumЬiа

Drosophilа mеlапogаster'thе fruit fly, thе workhorsе of еvolutionarygenetiсs. Thе way in whiсh it was tailorеd for suсh rеsеarсhis disсussеdin Kohler 1994.

undеrgraduatеs Alfrеd Hеnry sturtеvant' Сalvin Bridgеs' and Hеrmann Мullеr, who all playеd pivotal rolеs in gеnetiсs and еvolutionary Ьiology. Morgan, Bridgеs, and sturtеvant workеd togеthеr at СolumЬia until 1928 whеn thеy all movеd to thе Сalifornia Institцtе of Tесhnology (Сal Tесh)' whеrе thеy rеmainеd for thе rеst of thеir сarееrs.

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Drosophila sturtеvant produсеd thе first gеnеtiс map Ьasеd on thе rеalizаtion that thе frеquеnсy of сrossovеr еvеnts сould bе usеd to dеtегminе thе ordеr and loсation of gеnеs. Hе also workеd on a widе variеty of topiсs with еvolutionary impliсations, inсluding сhromosomal invеrsions, thе gеnеtiсs of spесiеs diffеrеnсеs, thе gеnеtiсs of dеvеlopmеnt, and thе phylogеny of thе gеnus. Bridgеs was among thе first to еxploit thе disсovеry that thе salivаry glands of Drosophilс сontainеd polytеnе сhromosomеs сonsisting of thousands of DNA strands rеsulting from rеpеatеd rounds of rеpliсation without сеll division. Thе rеsult is сhromosomеs visiЬlе at low magnifiсation with сharасtеristiс Ьanding pattеrns that allow homologous rеgions to Ье idеntifiеd aсross individuals and spесiеs. Bridgеs's dеtailеd dеsсriptions of thе Ьanding pattеrns allowеd linkagе and physiсal maps to Ье alignеd. Мullеr is bеst known for his NoЬеl Prizе_winning work on mutation. Bеginning in thе mid-1920s, Мullеr was thе first to ехploit thе faсt that сhromosomal invеrsions-сhromosomеs in whiсh a piесе appеars in rеvеrsе of thе normal ordеr-supprеss rесomЬination whеn in a hеtеrozygoцs сondi. tion with an uninvеrtеd сhromosomе. Mullеr found that hе сould usе an in. vеrtеd сhromosomе markеd with a dominant phеnotypiс markег, tеrmеd a Ьalanсеr, to сapturе and study thе propеrtiеs of сhromosomеs with thе norrnal gеnе ordеr. Initially hе usеd this tесhniquе to dеtесt сhromosomеs сarrying lеthal mutations' whiсh сan nеvеr produсе a homozygous adult. Mullеr mеasured thе lеthal frеquеnсy aftеr induсing mutation with Х-rays. Mullеr's сonсеpt of gеnеtiс load-mutational Ьaggagе that Мullеr saw as harmfulсamе from thеsе еarly ехpеrimеnts. Balanсеr сhromosomеs wеrе suЬsеquеntly dеvеlopеd for еaсh сhromosomе in D. mеlапogаstеr, and Ьalanсеrs rеmain onе of thе kеy advantagеs of doing gеnеtiсs in thе spесiеs. Shortly aftеr Morgan movеd to Сal Tесh, hе hirеd Russian sсiеntist Thеodo. sius DoЬzhansky as part of his tеam. DoЬzhansky quiсkly rosе to prominеnсе as a synthеsizer Ьу writing Geпetics апd the Оrigiп of Species (19З7), onе оf thе founding Ьooks of thе еvolutionary synthеsis,in whiсh hе assеrtеdthе pri maсy of a population gеnеtiс viеw of еvolution, basеd initially on rеmarkably littlе еmpiriсal еvidеnсе.At aЬout thе samе timе, influеnсеd Ьy Sturtеvant and his Russian mеntor Sеrgеi Сhеtvегikov, DoЬzhansky took up thе study of wild populations of Drosophilа pseudoobscurа. Populations of this сommon spесiеs of thе mountains of wеstеrn North Amеriсa arе polymorphiс for сhrоmosomal invеrsions. DoЬzhansky usеd this variation as thе Ьasis for a long sеriеs of еxpеrimеnts doсumеnting thе еffесts of thе thrее major evolutionary forсеs: sеlесtion,gеnеtiс drift' and gеnе flоw. In this, hе was grеаtly aidеd Ьy an .lfright еxtеnsivе сollaЬoration with Sеwall during thе latе 1940s. Modеrn еvolutionary work on Drosophilа сurrеntly has sеvеrаl major еmphasеs that grеw out of this еarliеr work. Thе study of variation аt thе molесular lеvеl was pionееrеd Ьy Riсhard Lеwontin, onе of DoЬzhansky's studеnts, who, starting tn 1965, еxploitеd thе disсovеry of protеin еlесtrophorеsis by Jaсk HuЬЬy and othеrs to dеmonstrаtеthаt a largе portion of gеnеtiс loсi in Drosopbilа spесiеs wеrе polymorphiс. This disсovеry of high

lеvеls of natural variz whеthеr gеnеtiс varr maintainеd by natur: сontrasting DоЬzhan with Мullеr's еmpha was a major faсtor in of Drosopbila to stuс quеnсing of Dros
Drosophila |asеdon thе rеalization that thе o dеtеrminе thе ordеr and loсai е г yo f t o p i с s w i t h е v o I u t i o n a r y эns' thе gеnеtiсs of spесiеs difthе phylogеny of thе gеnus. iсovеry that thе salivary glands mеs сonsistingof thousands of of rеpliсation without сеll diviv magnifiсation with сharaсtеr; rеgions to Ье idеntifiеd aсross эsсriptionsof thе banding patе alignеd. winning work on mutation. Bеst to ехploit thе faсt that сhroh a piесе appеars in revеrsе of whеn in a hеtеrozygous сondi: f o u n d t h а гh е с o u l d u s е а n i n rt phеnotypiс markеr, tеrmеd a i of сhromosomеswith thе norlе to dеtесtсhromosomеs сarryсе a homozygous adult. N4ullеr mutationwith Х-rays. Mullеr's -'that Mullеr saw as harmfulсer сhromosomеs wеге suЬsеD. melапogаstеr, and Ьalanсеrs )nеtiсsin thе spесiеs. : hirеd Russian sсiеntist Thеodonsky quiсkly rosе to pгominеnсе Эrigiп of Spеcies (1937), onе of :sis,in whiсh hе assеrtеdthе pri'n, Ьasеdinitially on rеmarkably nе, influеnсеdЬy Sturtеvant and ransky took up thе study of wild Populations of this сommon rеriса arе polymorphiс for сhroriation as thе Ьasis for a long sеof thе thrее major еvolutionary n this,hе was grеatly aidеd by an rringthе latе 1940s. с u r г е n t l yh а s s е v е г a lm a j o г е m rе study of variation аt thе mo3wontin' onе of DoЬzhansky's thе disсovеry of protеin еlесlonstratеthat a largе portion of nоrphiс. This disсovеry of high

lеvеlsоf natural variation in most spесiеs lеd to an aсrimonious dеbatе ovеr whеthеr gеnеtiс variation is gеnеrally sеlесtivеly nеutral, dеlеtеrious, or mаintainеd Ьy natural sеlесtion. Lеwontin hеlpеd to cata|уze this dеЬatе by сontrasting DoЬzhansky's viеw that muсh gеnеtiс vaгiation was adaptivе with Mullеr's еmphаsis on thе сosts of mutation and variation. This dеЬatе was a major fасtor in thе dеvеlopmеnt of population gеnеtiс thеory. Thе usе of Drosopbilа to study variation сarriеs ovеr to thе DNA lеvеl, whеrе thе sеquеnсing of Drosophila gеnomеs allows unprесеdеntеd prесision in thе study of еvolutionarypattеrns. Thе еasе with whiсh Drosophilа сan Ье rеarеd has lеd to its inсrеasing usе in thе study of еvolution in thе laЬoratory. Somе of thе first sophistiсatеd sеlесtion еxpеrimеnts on сontinuous traits wеrе сarriеd out in Drosophilа Ьу KеnnеthMathеr and ForЬеs \й/.RoЬеrtson in thе latе 1940s and еarly 1950s. SuЬsеquеntly,suссеssful artifiсial sеlесtion ехpеrimеnts took plaсе on many сharaсtеristiсs'еnсompassing moгphology and physiology (е.g.' fесundity, еgg sizе' dеvеlopmеntalratе, lifе span, rеsistanсеto еthanol)' Ьеhavior (phototaхis, gеotaxis, matе prеfеrеnсе), and aspесts of thе gеnеtiс systеm itsеlf (ratеsof rесomЬination, сhangе in varianсе rathеr than mеan valuе of traits). lfith thе ехсеption of sеx ratio and asymmеtry, hеritaЬlе variation еxists for еvеry trait studiеd. Studiеs of ехpеrimеntal еvolution, whеrе thе invеstigator сrеatеsan еnvironmеnt in whiсh natural sеlесtion сan take plaсе, is also an area of aсtivе rеsеarсh using Drosophilа. This approaсh has pаrtiсular rеlеvanсе in thе study of lifе historiеs and thе ultimatе origin of proсеssеs likе aging and matе сhoiсе. Thе study of spесiеs diffеrеnсеs, pionееrеd tn Drсlsophila Ьy Sturtеvant, Мullеr, and DoЬzhansky, is anothеr vеry aсtivе arеa of еvolutionary rеsеarсh. Thе gеnus is wеll suitеd to thе study of spесiation Ьесausе of thе numЬеr of сrossaЬlе spесiеs and thе rеlativе еasе with whiсh rеproduсtivе Ьarriеrs сan Ье identifiеd and quantifiеd. Jеrry Сoynе, onе of LеwontinЪ stu. dеnts, and his studеnt H. Allеn orr usеd this aссumulatеd data to makе rough еstimatеs of thе timе rеquirеd for spесiаtion in sympatriс and allopatriс populations. Thе gеnеs rеsponsiЬlе for aspесts of spесiеs barriеrs hаvе now Ьееn idеntifiеd in a numЬеr of Drosophila spесiеs pairs. \й/hilе thе study of Drosophilа dеvеlopmеnt datеs Ьaсk to thе 1920s, D. melапogаstеr Ьесаmе a prеmiеr modеl systеm for thе study of dеvеlopmеnt Ьasеd on thе dеtailеd study of thе Ьithorax сomplех Ьy Еd Lеwis, onе of Sturtеvant's studеnts' and thе systеmatiс mutation sсrееn for mutations with .$Иiееffесts еarly in dеvеlopmеnt Ьy Сhristianе Nusslеin-Volhard and Еriс sсhaus. Thеsе еfforts lеd to many of thе fundamеntal dеvеlopmеntal pathWays that arе сonsеrvеd widеly among animаls. Lеwis, Nusslеin-Volhard, and \Wiеsсhaus sharеd a NoЬеl Prize for this work tn 1'995. This ехtеnsivе Ьaсkground information on dеvеlopmеnt has cata|уzed thе study of thе еvolution of dеvеlopmеnt in Drosopbilс. Rеsеarсhеrs havе now Ьееn aЬlе to idеntify thе spесifiс gеnеSrеsponsiЬlе for many еvolutionary сhangеs in naturаl and ехpеrimеntaIDrosophilа populations.

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Drosophila в|вLloGRAPнY DoЬzhansky'T. 1937. Geneticsапd the Оrigin of Speсles.Nеw Yоrk: ColumЬia UnivеrsityPrеss. Kohlеr' k. 7994. Lords of thе F/y. Сhiсago:Univеrsityof Сhiсago Prеss. Lеwontin,R. С. 1'974.The GeпеticBаsis of ЕuolutionаrуСhапge.Nеw York: СolumЬiа UnivеrsityPrеss. Powеll' I. R. |997. Progrеssапd Prospeсtsiп ЕuolutioпаrуBiologу: ТЙe Drosophila Мodеl. Nеw York: oxford UnivеrsityPrеss. RuЬin, G. М., and Е. B. Lеwis. 2000. A Ьriеf historyo| Drosophilа'sсontriЬutions to gеnomеrеsеarсh. Sсiепсе287:2216-2218. Sturtеvant,A. H. 1965. А Нistorу of Gепеtics.Nеw York: Нarpеr and Row. -D.H. апd B.H.

E

E,cologicаI Geпetlcs

Есologicаl G enеtiсs, t|tr< s t u d y i n g n a t u г а ls е l е с t i o ..Еdmund B bеtiсal еntry studеnts, and сollесtеdth tiсs, is dеsсеndеd from tI don that natural sеlесtl ...W.F. R..Wеldon' еntry gеnеtiсs ovеr work likе \ gеnеtiс Ьasis suсh as thе mot|7P аrtах i а d omiпul а. logiсal gеnеtiсists to stu sponse to sеlесtion as l сhangеs in trait valuеs rе thеsе disсovеriеswеrе sп tеrm есologiсаl gепеliсs dеmonstraЬlе gеnеtiс fo trait variation in naturе l Тhrее typеs of invеsr thеrе arе dеmonstrations in thе moth Biston betul vеstigations of gеograph snails, that doсumеnt ho anothеr сhangе thе sеlес valuеs to Ье favorеd in d adaptivе еxplanatiоns fo dеmonstrations of adapt unсovеrеd thе signatuге s n a i l s h е l lp a t r е r n sT. h i r с сan Ьalanсе onе аnothе tion. Thеsе studiеs rеprе InnumеraЬlе thеorеtiсal tion gгеw from thе initi sеgrеgatеdеspitеЬеingа Еcologiсаl Geпеtiсs l s t u d i е sе l i m i n а г е da n y d

Spесiеs.Nеw York: СоlumЬia rsity of Сhiсago Prеss. tionаrу Сhапgе. Nеw York:

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' utioп сlrуB i ologу : TDe Drosophila tv of Drosophlla's сorrtгiЬutions :w \Ъrk: Нarpеr and Row.

-D.H' апd B.H.

E,cologicаIGеnetics (Е. B. Ford) Есolr>gicаlGеnetiсs, tЬrough its sеvеrаl еditions, prеsеntеdthе approaсh to studyingnatural sеlесtionin thе fiеld pionееrеd Ьy Е. B. Ford (sееthе alpha. bеtiсal еntry ..Еdrnund Brisсo Ford'' in this volumе), his сollеaguеs,and his studеnts,and сollесtеd thеir suссеssеs.This approaсh, сallеd есologiсal gеnе.!И. tiсs, is dеsсеndеd fгom thе еarly studiеs of R. C. Punnеtt and F. R. .07еldon that natural sеlесtion сan Ье studiеd еmpiriсally (sее thе alpЬаЬеtiсal еntry *W. F. R. Vеldоrr'' in this volumе). Thе advаnсе offеrеd Ьy есologiсal gеnеtiсsovеr work likе !7еldon's was a foсus on disсrеtеtraits with a simplе gеnеtiсЬasis suсh as thе variation in thе numЬеr of spots on thе wing of thе motь Pапахiс| dominцlа. Knowing thе gеnеtiс Ьasis of variation allowеd есologiсal gеnеtiсiststo study not only sеlесtion' Ьut also thе еvolutionary rеsponsе to sеlесtion :rs trait valuеs сhangеd ovеr timе or spaсе. Bесausе сhangеsin tгait valuеs rеflесtеdсhangеs in thе frеquеnсiеsof altеrnatеgеnеs' thеsеdisсovеriеswеге small-sсalеdеmonstrationsof еvolution in aсtion. Thе term ecologiсаl geпetiсs is dеrivеd from its foсus on trait variation with a dеrnonstraЬlе gеnеtiс foundation (gеnеtiсs) and its oriеntation to studying trait variation in natuге (есologiсal). Тhrее typеs of invеstigations donrirrаtе FordЪ Есologiсаl Gепеtiсs. First, thеrеarе dеmonstrations of еvolution in aсtion; thе saga of industrial mеlаnism in thе moth Bistott betulаriа is thе Ьеst-known еxarnplе. Sесond, thеrе arе invеstigations of gеographiс variation in trait valuеs, suсh as thе shеll сolors of snails, that doсumеnt how сhangеs in есologiсal fасtors from onе loсation to aпothеr сhangе thе sеlесtion prеssuгеs on orgаnisms аnd сausе diffегеnt trait valuеs to Ье favorеd in diffеrеnt loсations. Thеsе invеstigations dеmonstratеd adaptivе ехplanatiоns for gеographiс variation in сhагaсtеrs, сomplеmеnting dеmonstrations of adaptivе сhangе in timе. In somе сasеs, thеsе studiеs also unсovеrеd thе signаturе of random еvеnts as in thе so-сallеd arеa еffесts on snail shеll pattеrns.Third, thеrе arе studiеs of how diffеrеnt sеlесtion prеssurеs сan Ьаlаrrсеol1е i1l1othегаnd prеsегvе trait variation within a singlе population. Thеsе studiеs rеprеsеntеda partiсularly fеrtilе arеa of есologiсal gеnеtiсs. IпnumеraЬlе thеorеtiсal papеrs on thе population gеnеtiсs of Ьalanсing sеlесtion grеw from thе initial disсovеriеs that altеrnatе gеnеs would сontinuе to sеgrеgatеdеspitе Ьеing aсtеd upon Ьy strong natural sеlесtion. Есolсlgiсаl Gеnеtiсs was еnormously influеntial. Its сompilation of сasе studiеsеliminatеd any douЬt tlrаt natural sеlесгionwas an ongoing forсе and ) . t,

5З2

Еigеn сould Ье studiеd in rеal timе. Thе studiеs of gеographiс variation сonduсtеd by Ford and his сollеaguеsсomplеmеntеd thе work of othеrs' suсh as Gбtе Turеsson and Jеns Сlаusеn with plants (sее thе alphaЬеtiсal еntry ..Jеns Сlausеn'' in this volumе), F. B. Sumnеr with miсе, and Sеrgеi Сhеtvеrikov and Thеodosius DoЬzhansky with fliеs (sее thе alphaЬеtiсal еntriеs ..Sеrgеi Sеrgееviсh Сhеtvеrikov'' and ..Thеodosius DoЬzhansky'' in this volumе)' who wеrе making similar disсovеriеs, oftеn with сharaсtеrs lеss amеnaЬlе to gеnеtiс analysis. Thе waning of thе Ьook's influеnсе Ьеgan with thе disсovеry of Ьioсhеmiсal vаriation аnd сontinuеd through thе еmеrgеnсе of a sophisti. сatеd approaсh to studying сontinuously varying traits that arе morе rеprеsеntativе of thе stuff of еvolution than disсrеtе polymorphisms in visiЬlе сharaсtеrs. Nonеthеlеss, thе quеstions aЬout sеlесtion and еvolution prе. sеntеd in thе book' and thе сonviсtion advanсеd that есologiсal and gеnеtiс studiеsarе nесеssaryto undеrstandadaptivе еvolution, rеmain Ьеdroсk influеnсеs on modеrn еvolutionary Ьiology. в|вLIoGRAPHY Ford, Е. B. |975. ЕсologiсаlGеnetiсs,4thеd. London:Сhаpmanand Hall.

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Еigеn, Мanfrеd (ь. t927) Мanfrеd Bigеn is a Gеrman Ьiophysiсist and а formеr dirесtor of thе Мaх Planсk Institutе for Biophysiсal Сhеmistry in Gбttingеn. In 1967, togetЬ.er with Ronald Gеorgе.!Иrеyford Norrish and Gеorgе Portеr' hе won thе NoЬеl Prizе in сhеmistry for thе study of еxtrеmеly fast сhеmiсal rеaсtions. Bеginning in thе 1960s, Еigеn's rеsеarсhintеrеststurnеd to Ьioсhеmiсal quеstions, and during thе 1970s and 1980s hе formulatеd an еlaЬoratе thеory on thе еmеrgеnсе of lifе on еarth foundеd on mathеmatiсal сalсulations and ехpеrimеnts in viral populations. Еigеn's fundamеntal thеorеtiсal and philosоphiсal postulatе was thаt natural sеlесtion Was thе organizing prinсiplе rеsponsiЬlе not only for еvo. lution Ьut also for thе еmеrgеnсе of lifе. This сlaim was basеd on nеw advanсеmеnts in thе fiеld of molесular Ьiology. Starting in thе 1960s, it Ьесamе possiЬlе to dеsсriЬе еvolution Ьasеd on rеpliсation, mrrtation, and сompеtition not only of organisms Ьut also in mixturеs of sеlf-rеpliсating molесulеs and еnzymеs сatalyzing rеpliсation. Еigеn's rеsеarсh along thеsе linеs grеatly advanсеd thе work оf Ьioсhеmist Sol Spiеgеlman and othеrs in thе 1970s that dеmonstrаtеd thе еvolution in thе tеst tuЬе of viral RNA sеquеnсеs. Basеd on thеsе еxpеrimеnts' Еigеn dеvеlopеd his modеl for thе origin of lifе. Еigеn formulatеd a kеy nеw сonсеpt in origin-of-lifе study and virology ..quasi-spесiеs.'' сallеd thе Following thе сompеtition for Ьuilding Ьloсks in a population of RNA sеquеnсеsеngagеdin sеlf-геpliсation?a uniquе pattеrn of thе wholе population еmеrgеd Ьasеd on thе distriЬution of thе various mlrtants. This rеsulting population, thе quasi-spесiеs,rеflесtеdthе сonsеnsus sеquеnсе rеprеsеnting an avеragе of all thе mutants aссording to thеir

individual frеquеnсy. . of thе quasi-spесiеs, and dirесtеd еvolutiо sеlf_rеpliсation. In addition to сom opеration lеading to t sеvеral quasi-spесiеsr adjaсеnt unit. This со in thе sсеnario and al faсt that RNA sеquе lеngth (about 100 nu would aссumulatе,dс ordеf to сodе for prot madе it possiblе to 1 spесiеs without lеngtl funсtional protеins. I pеndеd on thеir еnсl form in thе riсh priл partmеnts сould thеn Еigеn,s thеory wal сhеmistry pгoduсеd l dant supply of amin, sеrvе as еnеrgy-riсh l sis of short gеnеtiс t sеlf-organization. Th and еmpiriсal assum wеrе sеvеrеly сritiсiz to idеas on thе еvolu tion of thе сonсеpt с thе prinсiplе of natu Ьut on any physiсal r standing thе rolе of lawful proсеss.

в|вLIoGRAPH

Еigеn, M. 1992.Stеpst Еigеn, М., lW. Gardinе of gеnеtiсinforma Fry, I. 2000. Тhе Еmеr Nеw Brunswiсk,N

Еigеn еog'faphiсvariation сonduсtеd ) work of othеrs, sцсh as Gбtе l thе alphaЬеtiсal еntry ..Jеns miсе, and Sеrgеi Сhеtvеrikov ..Sеrgеi hе аlphaЬеtiсalеntriеs )oЬzhansky'' in this volumе), 'ith сhаrасtеrslеss amеnаblе to шеnсеЬеgаnwith thе disсovеry gh thе еmеrgеnсеof a sophisti. ging trаits that arе morе rерrе:rеtеpolymorphisms in visiЬlе t sеlесtionand еvolution prесеd that есologiсal and gеnеtiс volution,rеmain Ьеdroсk influ.

сion:Сhаpпrаnand Нall.

-l.T.

l a foгmеr dirесtor of thе Maх n Gбttirrgеn.|n 1967, togеthеr ;еorgеPortеr, hе won thе NoЬеl fast сhеmiсal rеaсtions. Bеgin-rrnеdto Ьioсhеmiсalquеstions' Ltеdan еlaЬoratеthеory on thе matiсаlсalсulationsand ехpеrilosophiсal postulatе was that [е rеsponsiЬlеnot only for еvois сlaim was Ьasеd on nеw adogy. Starting in thе 1960s, it l on геpliсation' mutation, and in miхturеs of sеlf-rеpliсating 'n. Еigеn'srеsеаrсh along thеsе st Sol Spiеgеlmanand othеrs in n thе tеst tuЬе of viгal RNA sеn dеvеlopеd his modеl for thе rigin-of-lifеstudy and virology npеtitionfor Ьuilding Ьloсks in еlf-rеpliсation,a uniquе pattеrn t h е d i s t r i Ь u t i o no f t h е v a r i o u s si.spесiеs,rеflесtеd thе сonsеnthе mutants aссording to thеir

individual frеquеnсv' Еigеn disсovеrеd that, Ьasеd on thе spесifiс dynamiс of thе quasi-spесiеs,thе mесharrisrnсlf sеlесtion guarаntееd а r-rсlnrandom and dirесtеd еvolution toward a population сapаЬlе of aссuratе аnd fast sеlf-rеpliсation. In addition to сompеtition, Еigеn also postulatеd stagеs of molесular сoopегationlеading to thе еmеrgеnсеof a ..hypеrсyсlе,''an еnsеmЬlеin whiсh sеvеrаlquasi.spесiеsunits partiсipаtеd, еaсh еnaЬling thе rерliсation of thе adjасеnt unit. This сoopеration was dееmеd сrr-rсialto ovеrсoп1е a catсh-22 in thе sсеnario and allow furthеr еvolution. Thе diffiсulty stеmmеd from thе fасt that RNA sеquеnсеsin thе quasi-spесiеshad tо Ье limitеd to a сеrtain lеngth (about 100 Iruсlеotidеs).AЬovе this thrеshold, too many mutaгions would aссumulatе,dеstroying thе sеquеnсеs'idеntitiеs.At thе samе timе, in ordеr to сodе for pгotеins,muсh longеr сhains wеrе rеquirеd.Tlrе hypегсyсlе mаdе it possiЬlе to pull togеthеr thе information сontеnts of еaсh quasisресiеswithout lеngthеningindividuаl сhаins' thus еnaЬling thе synthеsisof funсtional protеins' Howеvеr' thе сoopеration of sеvеral quasi-spесiеsdеpеndеd on thеir еnсlosurе within a сompartmеnt, postulatеd Ьy Еigеn to foгm in thе riсh primoгdiаl ..soLlp.''Сoшpеtiгion аmong thе divеrsе сompartmеntsсould thеn pеrmit furthеr еvolution. Еigеn's thеory was Ьasеd on thе optimistiс аssumption that prеЬiotiс сhеmistry produсеd in thе primordial soup a far-from-еquiliЬrium, aЬundant supply of anrino aсids, nuсlеotidеs, and thеiг polymеrs. Thеsе сould sеrvе аs еnегgy-riсh Ьuilding Ьloсks and primitivе саtalysts for thе syrrthеsis of short gеnеtiс sеquеnсеs irnd for thе сruсiаl proсеssеs of Ьiologiсal sеlf-organization. This optimism аs wеll as sеvеral of Еigеn's rhеorеtiсal and еmpiriсal assumptions rеlating to thе quasi-spесiеsand thе hypеrсyсlе wеrе sеvеrеlyсritiсizеd Ьy othеr rеsеаrсhеrs.Nonеthеlеss' his сontriЬution to idеas on thе еvolution of gеnetiс information and to thе latеr formulation of thе сonсеpt of thе RNA world is indisputirЬlе. So is his сlаim that thе prinсiplе of natural sеlесtion Opеratеs not only on Ьiologiсal systеms Ьut on any physiсal systеms fulfilling сеrtain сonditions and that, notwithstanding thе rolе of random еvеnts' thе еmеrgеnсе of lifе was a naturally lawful proсеss. BIBLIOGRAPHY Еigеn,М. 1992.StеpstсlшаrdsLifе. Охford: Oхfоrd UrrivеrsityPrеss. Еigеn,М., W. Gardinеr,P. Sсhustеr, rrndR. Winklеr-Oswatitsсh. 1981.Тhе сlrigin of gеnеtiсinformаtion.SсiепtifiсАmеriсап244, no.4:78_|18. Fry, I' 2000. Thе Еmеrgепсеof Lifе tп Еаrth: А lListoriсаlапd SciеntifiсОt',aruiеш. -t.t. Nеw Brunswiсk,NJ: RutgеrsUnivеrsityPrеss.

.'3J

5З4

Епdosуmbiotiс Оrigiп of Еuhаrуotеs

ЕndosymЬiotiс origin of еukaryotеs PREсЕDЕNтs AND PRЕDEсЕssoRs onсе сontеntious' thе thеory is now aссеptеdthat all еukaryotеs (organisms сomposеd of сеlls with nuсlеi and truе сhromosomеs),inсluding thе familiar plant and animal organisms, еvolvеd from symЬiotiс mеrgеrs of Ьaсtеria. Сlеar gеnеtiсеvidеnсесonnесtsthе plastids (grееnphotosynthеtiсorganеl1еs) of algае to frее-living photosynthеtiс Ьaсtеria сallеd сyanoЬaсtеria. And Ьесausе algaе and plants havе a distant сommon anсеstor' this еvidеnсе сonnесts thе сyanoЬaсtеria to modеrn plants. So, too, thе oхygеn-using ..powеr paсks'' in сеlls, thе mitoсhondria, havе Ьееn traсеd via gеnеtiсs,physiology, and morphology to frее-living rеspiring Ьасtеria.For thе last 3 Ьilliоn yеars or morе' through mutations and gеnе trading' onе has thе samе kind of gеnеtiс еnginееring that goеs on in Ьiotесhnology firms. This aссumulation of DNA mutations and passing of sеts of gеnеs from onе kind of Ьaсtеrium to vеry diffеrеnt kinds is, and has Ьееn sinсе anсiеnt timеs' thе way of thе Ьaс. tеrial world. Yеt mеrgеrs, wholе.Ьody fusions, and pеrmanеnt allianсеs as ways of survival in thе hardеst of timеs has sеlесtеdЬaсtеrial assoсiationsto form nеw individuals. Baсtеria, Ьy virtuе of litеral takеovеrs, havе also еvolvеd into somеthing еlsе. By fusion of diffеrеnt kinds of Ьodiеs, rathеr than Ьy mutating and growing largеr, Ьaсtеria еvolvеd to Ьесomе largеr сеlls. Thе largеr сеlls, inсluding thе anсеstorsto all animals and plants, indееd all сеlls with nuсlеi (all еukaryotеs),еvolvеd Ьy symbiotiс mеrgеr. вAстЕRIAL ANсЕsтRY Baсtеria arе uЬiquitсlus organisms that arе prеsеnt in thе fossil rесord long Ьеforе any animals or plants. Baсtеria, not plants, еvolvеd photosynthеsis and сhеmiсal synthеsis,thе proсеssеsthat providе food to thе rеst of thе Ьiosphеrе.All Ьaсtеria sharе a сommon сеllular struсturеknown as prokaryotiс. Prokaryotiс сеlls, unlikе еukaryotiс сеlls, do not havе an еnсlosеd nuсlеus housing thеir DNA, Ьut rathеr an opеn аrеa сallеd a nuсlеoid in whiсh thе DNA rеsidеs. Typiсally thеrе arе no сеntriolеs, spindlеs' or miсrotubulеs (indееd thеrе is no mitosis as in еukaryotеs)' and prokaryotiс сеlls laсk mеmЬranе-bоundеd еnzymе saсs within whiсh organiс molесulеs arе oхidizеd. Baсtеria' whiсh arе all prokaryotiс, sharе mаny Ьut not all traits in сommon with thе еukaryotеs. Likе thе thrее main groups of morе familiar, largеr еukaryotеs-animals, plants, and fungi (all yеasts, molds, and mushrooms arе fungi)-Ьaсtеria аrе madе of сеlls that arе Ьoundеd Ьy dynaпriс protеin-riсh lipid mеmЬranеs.All сеlls from thе tiniеst Ьaсtеria to thе largеst еgg сеlls usе thе еnzymеs of thеir сomplех еnеrgy and сarЬon mеtaЬolism to produсе thеir own nесеssaryoutеr mеmЬranеs.Thе mеtaЬoliс maintеnanсе of thе dynamiс protеin-riсh, phosphorus.riсh, lipid-riсh mеmЬranеs еxсhangе сomponеnt parts. Сеlls usе foodstuffs as raw matеriаis. MеmЬranеs еnсapsulatеidеntity. Thе aЬsolutе nесеssityof сontinuity through spaсе and timе rеquirеs thе prеsеnсеof асtivе, intaсt mепrЬranеssurrounding all сеlls at

all timеs. МеmЬranеs сutiсlеs, dеfinе thе inl whiсh аrе madе of еit this impliеs that thе in prоtеin, and lipid соn< mеnt Ьеyond thе outеr thе uЬiquitous aсtivе waxy surfaсе, shеath, maintains idеntity of li

ALL LIFE FROM

All lifе forms on еarth proteins. Protеins, whi arе synthеsizеd on intr Ьosomеs look likе tin1 tron miсrosсopе. Меm fеaturеs of lifе that att lar anсеstors. Baсtеrial gеnеs,thos of DNA; thе сhеmiсal rial сhеmistry, arе iikс lеast 3,000 diffеrеntgс tеins. Baсtеrial сеlls gr known as fission. Thе .. appеaranсе than thе in еukaryotеs. Known isms always involvеs tuЬulеs (sееfigurе on 1 moving, as sееn throu[ prokaryotiс сеlls divi miсrotuЬulе-Ьasеdmo disсontinuity Ьеtwееn tiоnary gap in thе liviг Although сlеarly wе еvolvеd, somеhow, fro tеria and еukaryotеsa and thе mеmЬеrs of th forms of lifе arе сomр nuсlеi. For that rеaso Grееk). All Ьaсtеriа h and thе truе сhrom( protеins. Baсtеria' as a group mals' and fungi. Whе Ьrеathе sulfatе' сarЬo thеir small sizе, morс

Еndosуmbiotiс Оrigiп of Еukаrуotes

d that all еukaryotеs (organisms nosomеs),inсluding thе familiar symЬiotiс mеrgегs of Ьaсtеria. grееnphotosynthеtiс organеllеs ) Laсallеd сyanoЬaсtеria.And Ьеlon anсеstor' this еvidеnсе сon..powеr )' too' thе oхygеn-using . traсеdvia gеnеtiсs,physiology' г е r i a .F o r t h е l а s t З Ь i l I i o n y е a r s 4' onе has thе samе kind of gеnе,gy firms. This aссunrulation of ; from onе kind of baсtеriumto -rсiеnttimеs, thе way of thе Ьaсlns, and pеrmanеnt allianсеs as s е | е с t еЬd a с t е r i а аl s s o с i a t i o n st o of litеral takеovеrs, havе also liffеrеnt kinds of bodiеs, rathеr ia еvolvеdto Ьесomе largеr сеlls. 'll аnimals and plants, indееd all symЬiotiсmеrgеr.

prеsеntin thе fossil rесord long г plants' еvolvеd photosynthеsis 'ovidеfood to thе rеst of thе Ьio_ struсturеknown as prokaryotiс. o not havе an еnсlosеd nuсlеus a сallеd а nuсlеoid in whiсh thе 'iolеs, spindlеs, or miсrotubulеs tеs), and prоkaryotiс сеlls laсk h i с h o r g a n i сm o l е с u l е sа r е o х i _ sharе many Ьut not all traits in е main groups of morе familiar, Lgi(a11yеasts,molds, and mushls that arе Ьoundеd Ьy dynamiс thе tiniеstЬaсtеriato thе largеst nеrgyаnd сarЬon mеtaЬolism to n е s .T h е m е t а Ь о l i сm a i n t е n а n с е riсh, lipid-riсh mеmЬranеS еx:fs as raw matеrials. N4еmЬranеs of сontinuity through spaсе and еmЬranеssurrounding all сеlls at

all timеs. MеmЬranеs, and oftеn additional сovеrings suсh as се1lwalls and сutiсlеs, dеfinе thе insidе and thе outsidе Ьordеrs of all organisms, all of whiсh arе madе of еithеr prokaryotiс or еukaryotiс сеlls. In сhеmiсаl terms, this impliеs that thе insidе of any organism is in a statе of Watеr, salt' sugar, protеin, and lipid сonсеntration vеry diffеrеnt from its outsidе. Thе еnvironmеnt Ьеyond thе outеr mеmЬranе is еvеr-prеsеntand oftеn сhanging, but it is thе ubiquitous aсtivе mеmЬranе (whеthеr nakеd or supplеmеntеd Ьy skin, waxy surfaсе, shеath, or othеr additional outеr layеr) that еstaЬlishеsand maintаinsidеntity of living Ьеings. ALL L|FЕ FRoМ тHЕ ЕARLIЕsт сЕLLs All lifе forms on еarth makе protеins insidе thеir сеlls, inсluding mеmЬranе protеins.Protеins, whiсh arе long сhains of smallеr units сallеd amino aсids, arе synthеsizеd on intraсеllular tiny sphеriсal struсturеs сallеd riЬosomеs. Ri. bosomеs look likе tiny dots еvеn at high magnifiсation as sееn with an еlес. tron miсrosсopе. Меmbranе Ьioсhеmistry and protеin synthеsis are univеrsal fеaturеsof lifе that attеst to thе faсt that аll lifе еvolvеd from сommon сеllular anсеstors. Baсtеrial gеnеs,thosе of humans as wеll as all othеr animals, arе сomposеd of DNA; thе сhеmiсal сomposition of gеnеs, likе many othеr dеtails of Ьaсtеrial сhеmistry, arе likе thosе of thе largеr organisms. Most Ьaсteria havе at lеast 3,000 diffеrеnt gеnеs that dеtеrminе thousands of diffеrеnt еnzymе pro. tеins. Baсtеrial сеlls grow and rеproduсе Ьy rеproduсtivе division, whiсh is known as fission. Thе prokaryotiс сеll division proсеss is far lеss сomplеx in appеaranсеthan thе ..сhromosomеdanсе'' alignmеnt and sеparation proсеss in еukaryotеs. Known as mitosis' thе сеll division proсеss in nцсlеatеd organ. isms always involvеs movеmеnt insidе сеlls on littlе traсks сallеd miсrotubulеs (sееfigurе on pagе 536). Thе insidе of a еukaryotiс сеll is inсеssantly moving, as sееn through a miсrosсopе whеn thе сеll is alivе. Еvеn thе largеst prokaryotiс сеlls dividе Ьy fission; thеy laсk thе miсrotuЬцlеs and thе miсrotuЬulе-Ьasеdmovеmеntstypiсal of nuсlеatеdсеlls. Somе сlaim that thе disсontinuity Ьеtwееn Ьaсtеria and all othеr forms of lifе is thе largеst еvolu. tionary gap in thе living wor]d. Although сlеarly wе (i.е.,largеr forms of lifе сomposеd of nuсlеatеd сеlls) еvolvеd, somеhow, from Ьасtеrial prеdесеssors, thе diffеrеnсеs Ьеtwееn Ьaсtеria and еukaryotеs arе signifiсant. Thе major diffеrеnсеs Ьеtwееn Ьaсtеria and thе mеmЬеrs of thе animal' plant, and fungal kingdoms is that all largеr forms of lifе arе сomposеd of сеlls that harЬor douЬlе mеmЬranе_Ьoundеd nuсlеi. For that rеason thеy arе еukaryotеs (еu=truе, karyon=kеrnеl, sееd; Grееk). All Ьaсtеria havе DNA, Ьut thеy lасk Ьoth thе nuсlеar mеmЬranе and thе truе сhromosomеs whеrе thе DNA is paсkagеd with spесial protеins. Baсtеria, as a group' are far morе mеtaЬoliсally divеrsе than plants' animals, and fungi. Whеrеas all thе lattеr Ьrеathе oХygеn' somе Ьaсtеria сan Ьrеathе sulfatе' сarЬon dioхidе, nitratе' or еvеn arsеnatе. Baсtеria, dеspitе thеir small sizе, morе anсеstrаl lifеstylе, and rеputation as parasitеs and

5З5

536

Епdosуmbiotiс Оrigin of Еukarуotes

fiеd with various lеvеls. diffiсrrlt to provе, symЬ swimming motility (sее ond, now provеn dеfin сеll, thus allowing thе сt сеnt and tlrеrеforе thе t

Thе nuсlеoсytoskеlеtalorganellar systеmof еukaryotеs.Тhе systеm,Ьy hypothesis,еvolvеd from a symЬiotiс mеrger of a motilе еuЬaсtеrium(a sulfidеoxidizing spiroсhеtеthаt bесamеthе undulipodium)with аn arсhaеЬaсrеrium (a sulfidogеniсthеrmoaсidophilсodеsсеndantwith Тhermoplаslzasp.).Sее Мargulis еt al. 2005.

gеrms' arе in faсt morе profiсiеnt and Ьгoadly skillеd at many сhеmiсal tasks than arе largеr lifе forms.

limitеd to thе anсеstors our planеt grееn, lеd tс quisition of photosynth еukaryotеs, algaе, and ; But how did tliе dеfir Thе first nuсlеatеd miсl fеrеnt kinds of Ьaсtеria laсkеd oxygеn). Onе t1 hydrogеn sulfidе gas fr volсaniс origin. This or1 tion, hypothеtiсally aсq Ьy symЬiogеnеsis.Thе s Sugars' aсеtatе' or orga sulfidogеn, was a whiz l minutе. Thе nuсlеusitst

ЕARLIЕsт NUсLЕAтЕD сELLs How might our Ьaсtеrial anсеstors havе еvolvеd to form thе еаrliеst nuсlеatеd сеlls? Thе еvolutionary proсеss always involvеs thе сapaсity for rampant population growth far Ьеyond thе еnvironmеnt to sustain it (i.е., Ьiotiс po..сhесks', growth tеntial),thе gеnеrationof inhеritеd variation, and thе on of the population (inсluding its variants) Ьy thе failurе of thе Ьiotiс potential to Ье rеaсhеd. The inhibition of maximal population growth Ьy еlimination of many' for whatеvеr rеason' is сallеd natural sеlесtion. Naturаl sеlесtion maintains hеalthy rеproduсtivе populations оf many typеs of organisms' Ьut it doеs not produсе thеm in thе first plасе. .!7еl1, thеn, how is inhеrited variation gеnеratеd? Although random mutation сlеarly еxists and has Ьееn prodigiously doсumеntеd, inhеritеd variaгion is gеnеratеd in many morе diffеrеnt and important ways than via random mutation. Indееd, random mutation almost сеrtainly did not produсе nuсlеatеd сеlls from Ьaсtегia.Rathеr, thе maior modе of еvolutionаry variariоn in Ьaсtеria that lеd to thе first nuсlеatеd сеlls is likеly to havе Ьееn via a proсеss сallеd symbiogеnesis. This proсеss is alliеd to symЬiosis' whiсh is thе есologiсal rеlationship Ьеtwееn Ьеings of diffеrеnt typеs (diffеrеntly nanrеd organisms). Symbiogеnеsisis simply a protraсtеd,long-lastingphysiсal assoсiation, usually Ьеtwееn diffеrеnt spесiеs.It is аn evolutionаry, Darwirrian proсеss. SymЬiogеnesis rеfers to thе appеaranсе of a nеw trait, Ьеhavior' tissuе' organ, organism, spесiеs, or othеr highеr taxon as a геsult of an idеntifiaЬlе long-tеrm symЬiosis. Sеvеral еvolution-сhangingsymЬiosеshavе Ьееn idеnti-

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Thе [9(2)+2] rniсrоtuЬrr sееn witlr elесtron miсrtl of еvolutiсlnary importal сiliа. zoospt-lrеsof masti pгojесtions suggеsts its с

Еndosуmbiotic Оrigin of Еuhаrуotes

lliiliiilt

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karyotеs.Thе systеm' Ьy I a motile еuЬaсtеrium(a sulfidе. l i u m )w i г ha n a г с h а е Ь a с r е r i u m мttЬ'T bermoplаsmа sp.). See

y skillеd at many сhеmiсal tasks

fiеdwith various lеvеls of assuranсе.Although thе еarliеstсhangе is thе most diffiсult to provе' symЬiogеnеsis lеd to thе еukaryotiс organism itsеlf, with swimming motility (sееfigurе Ьеlow) аnd thе сapaЬility for mitosis; thе sесond, now provеn dеfinitivеly, lеd to thе prеsеnсе of mitoсhondria inside a сеll, thus allowing thе сеll to Ьrеathе oxygеn. Thе last symЬiosis, thе most rесеnt and thеrеforе thе onе aЬout whosе history wе arе most сonfidеnt' was limitеd to thе anсеstors of algaе and plants. This symЬiosis, whiсh rеndеrеd our planеt grееn, lеd to thе prеsеnсе of сhloroplasts insidе thе сеlls. By aсquisition of phоtosynthеtiс prokaryotеs (сyanoЬaсtеria), thе photosynthеtiс еukaryotеs,algaе, and plants appеarеd on еarth. But how did thе dеfining fеaturе of a еukaryotе' thе nuсlеus itsеlf, еvolvе? Thе first nuсlеatеd miсroorganisms likеly еvolvеd Ьy thе mеrgеr of two diffеrеntkinds of Ьaсtеria Ьut undеr anoxia (i.е.,еnvironmеntal сonditions that laсkеd oхygеn). Onе typе of Ьасtеrium, сapaЬlе of fеrmеntation, produсed hydrogеn sulfidе gas from amЬiеnt еlеmеntal sulfur gloЬulеs, proЬaЬly of volсaniс oгigin. This organism, сallеd a sulfidogеn Ьесausеof its gas produсtion, hypothеtiсally aсquirеd an еntirе gеnomе of anothеr typе of Ьaсtеrium by symЬiоgеnеsis.Thе sесond organism also livеd on organiс foodstuffs (е.g., sugars' aсеtatе' or organiс aсids). But thе sесond Ьaсtеrium, whiсh is not a sulfidogеn, was a whiz at loсomotion: it swam morе than 100 miсromеtеrs a minutе. Thе nuсlеus itsеlf еvolvеd only aftеr intеgration, that is, aftеr thе first

llvеd to form thе еarliеst nuсlе. nvolvеsthе сapaсity for rampant l е n t t o s u s t e i ni t ( i . е . 'b i o t i с p o ..сhесks'' on growth of , and thе . failurе of thе Ьiotiс potеntial to rlation growth by еlimination of 'rаl sеlесtion. Natural sеlесtion оf many typеs of organisms, Ьut эratеd?Although random mutad o с u m е n t е di'n h е г i t е dv а r i a t i o n rportant ways than via random сеrtainlydid not produсе nuсlеl o d е o f е v o l u t i o n a г yv a r i a t i o n i n likеly to havе Ьееn via a proсеss э symЬiosis,whiсh is thе есologtypеs (diffеrеntly namеd organlong-lаstingphysiсal assoсiation, volutionary,Darwinian proсеss. t n е w t r a i t , Ь е h a v i o r ,t i s s u е ,o r on as a rеsult of an idеntifiaЬlе ging symbiosеs havе Ьееn idеnti-

-&.t. Thе [9(2)+2]miсrotuЬulеarraу of all undulipodiain transvеrsеthin sесtionas sееnwith еlесtronmiсrosсopy.Thе oЬsеrvationthat this sеme(multigeniсtrait of evolutionaryimportanсе)is сonsеrvеdin spеrmtails' vеrtеЬratеsеnsory сilia, zoosporеsof mаstigotеmolds, and myriad othеr intrinsiсallymotilе сеll projесtionssuggеstsits сommon anсеstry.

5З7

5З8

Епdosуmbiotiс Оrigiп of Еukаrуotes Ьaсtеrium (thе sulfidogеniс arсhaеbасtеrium) mеrgеd with thе swinrming Ьaсtеrium to fornr thе symЬiotiс anсеstor of all nuсlеatеdсеlls. Thе еarliеst produсts of thе first proposеd symЬiogеnеtiс mеrgеr wеrе amitoсhondriatе protists, сеlls that did not possеss mitoсhondria. Thе group' сallеd arсhaеprotists (Мargulis and Sсhwartz 1998), still survivеs in airlеss mцds and anoхiс inrеstinеs.Many gеnеra, dеsсеndaIrtsof thеsе аmitoсhondriаtе сеlls, still livе today, Ьut thеy rnust Ье sought irr strаngе haЬitats Ье. сausе thеir rеlativеs with mitoсlrondria in this oхygеn-riсh world grеatly outnumЬеr thеm. Indееd, еntirе familiеs suсh as thе Triсhomonadida and Calonymphida still thrivе in organiс-riсh anoхiс haЬitats suсh as thе guts of tеrmitеs and wood-еatins roaсhеs. PRoтoст|sт

D|VЕRslтY: KEY тo сELL EvoLUт|oN

Thе grеat group of rеliсt nuсlеatеd miсroorganisms, thе еarliеst nuсlеatеd сеlls, and thеir еxtant dеsсеndants is сallеd Protoсtista. This group, whiсh today is еstimatеdto сontain somе 250'000 spесiеs,is сonsidеrеdits own kingdom in thе fivе-kingdom сlassifiсationsсhеmе.Thе Protoсtists inсludе all thе algaе, thе so-саllеd protozoa' thе slimе molds, and many moге OЬsсurе .Woеsе groups. Thе thrее-domain molесular-biologiсal сlassifiсationof Сarl lumps plants' animals, and fungi togеthеr in a singlе kingdom and thе pro.W.oеsе toсtists are put with all nuсlеatеd organisms into Dornain Еukaryа. sеparatеsthе prokaryotеs into two Ьасtеrial groups, Ьаsеd mainly on diffеrеnсеs in thе dеtails of thеir riЬosomе's RNA. onе is thе Arсhеaе (= n..1'".Ьaсtеria) and thе othег is Еubaсtеria' ln thе sсhеше of nuсlеatеd сеll origins outlinеd aЬovе, thе mеrgеr was Ьеtwееn an arсhaеЬaсtеrium (thе sulfidogеniс arсhеan, similar to today's Thermoplаsmа асidophilа) and a еuЬaсtеrium (similar to todаy's Spiroсhаеtа,a genus of snakеlikе swimmеrs). Thе protoсtists inсludе all photosynthеtiс еukaгyotеs that dо not grow from еmЬryos, as plants do (sее figurе)' Familiar ехarnplеs inсludе diatoms; rеd, grееn, and Ьrown sеawееds (inсluding kеlp); сhrysophytеs; phytoplankton; and all othеr algaе. (Thе bluе-grееnsarе not inсludеd; thеy arе not algaе Ьut сyanoЬaсtеria Protozoa (an obsolеtе tеrm insofar as iг suggеstsanimals), сiliatеs, slimе nеts, foгaminifеra, сhytгids, and mаny othеr еvеn morе oЬsсurе ta-xa arе in thе grеat kingdom of Protoсtista. It is in this unruly grouP of еukaryotiс miсroЬеs and thеir many nrultiсеllular dеsсеndantsthаt so many fеaturеs of nuсlеatеd organisms еvolvеd: mitoсhondriatе and plastidiс сеlls, mitosis and mеiotiс sех, animal сеll junсtions (sеptatеjtrnсtions,dеsmosomеs)' and animal-stylе multiсеllularity. Еvеn еyеs (in сеrtain dinoflagеllatеs), сеll Pеnеtrationdеviсеs (in Apiсоmplехans, thе group to whiсh thе malarial parasitе Ьеlongs),and hunting and shеll-making (in thе prеdatory and аgglutinating foraminifеra' rеspесtivеly)еvolvеd in thеsе groups of protoсtists. Нypothеtiсally, thе origin of nuсlеatеdсеlls (еukaryosis)oссurrеd Ьy thе middlе of thе Protеrozoiс еon. Thе datеs for еvolution of elny innovation must Ье sеt Ьy oЬsеrvаtions in tlrе fossil rесord. Tl.rеrеforе,it is likеly that thе symЬiogеnеtiс еvolutionarу sеquеnсеdеsсгiЬеdaЬovе oссuгrеd priсlr to thе dеposition in

z, ц, ;Е (J IE n(

ARснЕAвAстЕR L**--*

origin of еukaryotеsfror thеory. Lеft to right: Thе еuЬaсtеriаlto form апrir Intгасеllularmotility,inс of digestionof oxygеn-b mid-Protеrozoiс.Somеo that Ьесomе thе anсеsto

sеdimеntsof suсh wеll-p son еt аl. 1999) or thе sр PuЬlishеd еvidеnсе dс oгigin оf thе nuсlеаtеd tеthеrеd in a pесuliar s toсtists' сallеd thе karу

Епdosуmbiotiс Оrigiп сlf Еukаrуotеs L) mеrgеd with thе swimming 'll nuсlеatеdсеlls. y m Ь i o g е n е t im с е r g е rw е r е a m i ;еss mitoсhondria. Thе group' r,1998\' still survivеs in airlеss :sсеndantsof thеsе amitoсhonsought irr strangе haЬitats Ье:his oхygеn-riсh world grеatly :h as thе Triсhomonadida and хiс haЬitatssuсh as thе яuts of

LL ЕVoLUт|oN ganisms, thе еarliеst nuсlеatеd otoсtista.This group, whiсh toсiеs, is сonsidеrеd its own king. :. Thе protoсtists inсludе all thе llds, and many morе obsсurе .s7oеsе :аl сlassifiсation of Сarl a singlеkingdom and thе pro; into Domain Еukarya. \Иoеsе groups'basеd mainly on diffеr' onе is thе Arсhеaе (= arсhaе;сhеmеof nuсlеatеd сеll origins L arсhaеЬасtеrium(thе sulfidorcmа аcidophilа) and a еuЬaсLsof snakеlikеswimmеrs). lkaryotеsthat do not grow from ехamplеs inсludе diatoms; rеd, ; сhrysophytеs;phytoplankton; inсludеd;thеy arе not algaе Ьut ofar as it suggеstsanimals), сilimany othеr еvеn morе oЬsсurе It is in this unruly group of еuLrdеsсеndantsthat so many fеalсhondriatе and plastidiс сеlls, lsеptatеjunсtions, dеsmosomеs)' (in сеrtain dinoflagеllatеs)' сеll oup to whiсh thе malarial parar thеprеdatоryаnd agglutinаting lups of protoсtists. еukaryosis)oссurrеd Ьy thе midution of any innovation must bе эrе,it is likеly that thе symЬiogе:сurrеdprior to thе dеposition in

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origin of еukaryotеsfrom spесifiсЬасtеriallinеagеs:sеrialеndosymЬiotiс thеory. Left to right:Thеrmoplasma-like arсhaеbaсtеriamеrgе with spiroсhеtе еuЬaсtеrialto form amitoсhondriatеprotists in thе lowег Protеrсlzoiсеon. Intraсеllularmotility, inсludingphagoсytosis'potеntiatеsthе ingеstionЬut laсk Ьaсtеrialanсеstorsof mitoсhondriaЬy thе of digеstionof oхygеn-Ьrеаthing mid-Protеrozoiс.Somе of thеsеaеroЬiсprotistsingеstand rеtainсyanoЬaсеria that Ьесomеthе anсеstorsto thе plastidsof algaеand plants.

sеdimеntsof suсh wеll.prеsеrvеdmiсrofossils as Vапdаlospbаeridium (Samuеlsson еt al. 1999) or thе spiny sphеrеsin thе Doushantou. PuЬlishеd еvidеnсе doсumеnts that thе first struсturеs that appеarеd in thе origin of thе nuсlеatеd сеll wеrе not ffее nuсlеi. Rathеr, thе nuсlеus Ьеgan tеthеrеd in a pесuliar struсturе' an organёllar systеm still insidе many protoсtists' сallеd thе karyomastigont. Thе karyomastigont is an еxamplе of а

5J9

'40

Еndсlsуmbiotiс Оrigiп of Еиkаrусltеs D:rrwinian impеrfесtiorrand oddiry from wlriсh а pаth оf history rrrаyЬе ге. сonstruсtеd.Thе signifiсanсеof thе karyoпlasгigont,аn organеllаr systеm in whiсh a nuсlеus is еmЬеddеd, was dеsсriЬеd in thе еarlY yеars of thе twеntiеth сеntury (Janiсki 1915). Мinimаlly thе karyornastigontсonsistsof а nuсlеus,i.t nuсlеar сotlllесtor (сallеd a rhizoplаst in еarly pгotozoologiсal litеrаturе)'irnd an undulipodium (thе 9+0 kinеtosomе/сеntriolе and its shаft, thе 9+2 miсrotuЬular aхonеmе). (Somе prеfег to writе this univеrsal pattеrn of ninеfold Whеn symmеtry of thе miсrottrЬulеsin thе shaft m()rеaссuratеlyas [9(2)+2].) thе сеntriolе in mitosis dеvеlopsinto thе kinеtosomе of thе motility organеllе, wе arе sееing thе lеgaсy of thе swimmеr сomponеnt of thе еarliеst еukaryotеs. Тhе struсturе and Ьеlravior of protoсtists thаt laсk mitoсhorrdriа undеr anoхiс сoгrditiсlnsand today's motility s,vmЬiosеsin many organisms with swimming baсtеria' sllсh othеrwisе odditiеs and pесuliaritiеs, arе undеrstood in thе сontеxt of thеir еvolution. Тhе nuсleus itsеlf is most likеly а produсt
Sсаrсy' D. G. l987. Ph,vlogе еukaгyotiс nuсlеoсytоpl Netu Yorh Асаdеmу of ! 'Woеsе, С.2О02. С)n tlrс еvol Sсicпct'sUSА 99: 8742-

Еthology and thе stu

\Х/hilе rlirny individuals l Austrian Konrad Lorеnz (1907-1988) arе rеgаrdе еthology as a rесognizеds trаvеlеd to Lеidеn in 193 сollaЬorаtors. L
and his visionary brе.rсlth pеrimеntal appгoaсh to th As wеll as bеing praсt rvrotе аЬout its mеthodol ogists slrould attеmPt to a vеlop? Whаt arе its imn еvolvе? Lоrеnz strеssеdt} Ьеhaving spontanе()uslyЬ himsеlf shoсkеd Ьy thе dе in Ьеhavioristiс psyсholog vеlopmеnt of an еthogra Ьеhаviогs-is thе staгting In 797З, Lorеnz and T Gеrman zoologist Karl vt disссlvегiеsсonсеrniпg or Ьеhavior pattеrns.''Von I languagе of honеy bееs.\ сomparаtivе study of thе сonstruсt thеir phvlogеny in tЬe Aпаtidоe (waterfo

morphology in rесonstru fоr thе ассеptanсесlf еthс Еarly еthologistsWеrе and TinЬеrgеn mеt at a W idеа of a fiхеd aсtion pat rеpеatеdly еliсitеd Ьу а s t i с u l а rp с с k i n g Ь е h e v i t ' simplе modеls of thе adul с o l l с е p tt r i . r f i х е d а с r i о n s i g n s t i l n u l ia n d f i s с d а с t Ье undеrstood in thе сon еvolutionary сontехts fat

Еthrэlсlgу апd the Studу of Bеhаuiorаl Еuolutioп

сh a path of history may Ье rеr i g o n t .a n о r g a n е l I a гs у s t е m i n thе early yеars of thе twеntiеth astigontсonsistsof a nuсlеus, a protozoologiсallitеraturе),and lе and its shaft, thе 9+2 miсro; univеrsal pattеrn of ninеfold е aссuratеl1. as L9(2)+2]').W.hеn lsomе of thе motility organеllе, lnеnt of thе еarliеst еukaryotеs. -hat lасk mitoсhondria undеr iosеs in many organisms with rd pесuliaritiеs'arе undегstood tsеlf is most likely a produсt of гs (arсhaеЬaсtеriumsulfidogеn Lrt of thе karyomastigont from еukaryotеsis Ьasеd on thе innuеl R. Clеvеland (\892_1971) f thе Dеpartment of Zoo|ogу at rеland providеd dеtails of сеll rnd othеr сеll parts in mitosis) olution Ьy rесognizing thе aЬil. lntly of thе nuсlеi in mitoсhonLmitoсhondria. Prеsеrvation of ing thе unprесеdеntеd 16-mm lf intеrеstto thosе who wish to

inе struсturе of thе flаgеllatе oorganisms.Proсееdiпgs of thе 83. геs.Part II. Thе gеnеrа iloпуmpbа.on thе paraЬasal rnd amitоsis.Zсitsсhrift fйr l'ites. Uпiuеrsitу of Са|iforпш ..Impеrfесtior-rs 05. аnd odditiеs'' 7 5-19] . w York: Simon and Sсhustеr. Сalifornia Prеss. Ioms:Ап lllustrаtеd Guidе tсl tbе H. Frееmаnаnd Сompany. trganiс-wallеdmiсrofossils from ]rееnland. P reсаmbriап Re seаrсh

Sеarсy,D. G. 1987. Phylogеnеtiсаnd рhеnotypiс rеlationshipsbеtwееn thе еukaryotiс nuсlеoсytoplasmand thеrmophiliс ArсhaеЬaсtеria.Аппаls of the Neш York Aсаdеmу rlf Sсiепсes 5ОЗ 168_\79. Woеsе, С. 2002. On thе еvolution of сеlls. Proсееdiпgs of tbе Nаtiсlпаl Асаdemу of

SсiепсеsUSА 99: 8742_8747.

-L.^Д. апd D.Sа.

Еthology and thе study of bеhavioral еvolution Whilе many individuals havе сontriЬutеd to thе dеvеlopmеnt of еthology, Austrian Konrad Lorеnz (1903_1989) and Dutсhman Niko TinЬеrgеn (1907*1988) arе rеgardеd as its сеntral figurеs' whosе еfforts еstаЬlishеd еthology as a rесognizеdsubdisсiplinеof еvolutionary Ьiology. \Иhеn Lorenz trаvеlеdto Lеidеn in 19З6, hе mеt TinЬеrgеn and thеy Ьесamе friеnds and сollaЬorаtors.Lorеnz was known for his grеat passion for watсhing animals and his visionary Ьrеadth,whilе TinЬеrgеn Ьrought a morе analytiсal and ехpеrimеntalapproaсh to thе study of animal Ьеhavior. As wеll as Ьeing praсtitionеrs of еthology, Ьoth Lorеnz and TinЬеrgеn Wrotе aЬout its mеthodolоgy. TinЬеrgеn idеntifiеd four quеstions that еthologistsshould attеmpt to answеr aЬout any spесifiсЬеhavior:How doеs it dеvеlop? NИhat arе its immеdiatе сausеs? \й/hat is its funсtion? How did it еvolvе? Lorеnz strеssеdthе importanсе of spеnding hours watсhing animals ЬеhavingspontanеouslyЬеforе formulating any hypothеsеs'and hе profеssеd himsеlf shoсkеd by thе dееp ignoranсе of animals that hе thought hе dеtесtеd in bеhavioristiсpsyсhologistssuсh аs John B. Watson (1878_1958). Thе dе. vеlopmеnt of an еthogram for a spесiеs-a standardizеd list of oЬsеrvaЬlе Ьеhaviors-is thе starting point for еthologiсal rеsеаrсh. |п 197З, Lorеnz and TinЬегgеn sharеd thе Nobеl Prizе for mеdiсinе with Gеrman zoologist Karl von Frisсh (1886-1982). Thеy wеrе сitеd ..for thеir disсovеriеsссlnсеrningorganization and еliсitation of individual and soсial Ьеhavior pattеrns.'' Von Frisсh is Ьеst known for his disсovеry of thе danсе languagеof honеy Ьееs.Von F'гisсh'sstudеnt,Martin Lindauеr, сonduсtеd a сomparativе study of thе danсеs of sеvеral сlosеly rеlаtеd Ьее spесiеs to rесonstruсtthеir phylogеny, similar to Lorеnz's study of Ьеhavioral homologiеs in tЬе Апаtidаe (waterfowl). Thе idеa that Ьеhavior сould Ье as rеliаЬlе as morphology in rесonstruсtingthе rеlationshipsamong spесiеswаs signifiсant for thе aссеptanсе of еthology as an important part of еvolutionary Ьiology. Еarly еthologists wеrе intеrеstеd in thе сonсеpt of instinсt; indееd' Lorеnz and TinЬеrgеn mеt at a workshop on this topiс. Lorеnz is аssoсiatеdwith thе idеa of a fiхеd aсtion pаttеrn-a сomplех Ьеhavior that сan Ье rеliaЬly and rеpеatеdlyеliсitеd Ьy a spесifiс sign stimulus. TinЬеrgеn showеd that a partiсular pесking Ьеhavior of hеrring gull сhiсks сould Ье еliсitеd Ьy rеlativеly .Whilе simplе modеls of thе adult Ьеak with a prominеnt rеd spot. thе gеnеral сonсеpt of a fiхеd aсtion pattеrn appliеs aсross numеrous spесiеs'partiсular sign stimuli and fiхеd,aсtionpattеrns arе highly spесiеs-spесifiсand сan only bе undеrstood in thе сontеХt of thе partiсular dеvеlopmеntal,adaptivе, and еvolutionary сontехts faсеd Ьy mеrтЬеrs of thе spесiеs.Lorеnz's сonсеpt of

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Еthologу апd thе Studу of Bebаuiorаl Еuolutiсln instinсt was strongly сritiсizеd in thе 1950s Ьy Amеriсan psyсhоlogistDaniеl Lеhrman for Ьеing insuffiсiеntly attunеd to dеvеlopmеntal proсеssеs.TinЬеrgеn's inсlusion of dеvеlopmеnt among his four quеstions rеprеsеntеdhis attеmpt to aссommodatе Lеhгman's сritiquе. SuЬsеquеntly' many yеars of fruitlеss ..natufе vеrsus nurturе'' dеЬatеs аnd сonfliсts ovеr dеfinitions havе madе сurrеnt еthologists lееry of thе сonсеpt of instinсt. Nеvеrthеlеss, thе study of inhеritеd Ьеhavioгal adaptations is still аn lmportant part of еthology. Arеas of partiсular сurrеnt intеrеst and aсtivity within еthology inсludе prеdator-prеy intеraсtions and thе various systems of antiprеdatory alarm сalls found in a widе rangе of spесiеs, thе soсial dominanсе struсturеs that also vary widеly aсross diffеrеnt spесiеs,сomparаtivе studiеs of soсial play, thе mеmory dеmands of food сaсhing аnd rеtriеval, tool manufасturе and usе, and thе еxistеnсе of сulturally transmittеd traits. Еthology сan Ье undеrstood Ьy сontrast to altеrnativе approaсhеs to thе .!Иithin study of Ьеhavioral еvolution in Ьiology and psyсholоgy. Ьiology, Ьеhavioral есolоgy appliеs population-lеvеl modеls of еvolution to thе undеrstanding of animal Ьеhavior. Bеhavioral есologists frееly Ьorrow modеls from есonomiсs and gamе thеory, whiсh rеprеsеnt individuаl organisms as rational optimizеrs and allow analysis of intеraсtions Ьеtwееn еnvironmеnt and Ьеhavior on rеproduсtivе fitnеssand thе distriЬution of bеhavioral traits. Unlikе traditional еthology, Ьеhavioral есology has Ьееn lеss сonсеrnеd with immеdiatе сausеs of thе Ьеhavior of individual аnimals or its dеvеlopmеnt. Месhanisms rеsponsiЬlеfor gеnеratingoptimal Ьеhavior arе oftеn simply assumеd and not ехplainеd. Nеvеrthеlеss,thеrе hаs Ьееn signifiсant сrossovеr Ьеtwееn thе two suЬdisсiplinеs, with many of thе originators of Ьеhavioral есology having first trainеd as еthologists. Сomparativе psyсhology also takеs an еxpliсitly еvolutionary approaсh to animal Ьеhavior. Howеvеr, unlikе Ьiologists, who tеnd to Ье intеrеstеd in diffеrеnсеsamong individuals and among spесiеs,psyсhologists arе trainеd to loоk for gеnеral pattеrns of Ьеhavior and prinсiplеs of lеarning' somеtimеs .!7hеrе rеfеrrеd to as laws of lеarning. сomparativе psyсhologists do sее diffеrеnсеs Ьеtwееn spесiеs, thеy often rеgard thеsе as rеvеaling stеps on an еvolutionary laddеr to full-Ьlown human сognition, and thеy arе oftеn drаwn to invеstigatingtasks to mark thrеsholds of сognitivе sоphistiсation.Thus, for ехamplе, thеrе has Ьееn muсh intеrеst among сomparativе psyсhologistsin finding out whiсh spесiеs сan rесognizе thеmsеlvеs in mirrors, сan pass a falsе Ьеliеf attriЬution task, or сan lеarn a human languagе.Мany еthologists prеfеr to oЬsеrvе animals in natural or naturalistiс haЬitats. Somе sсiеntists, to Ье found on Ьoth sidеs of this dividе, arе pluralists who Ьеliеvеthat thе intеgrativеstudy of animal Ьеhavior rеquirеs Ьoth field and laЬoratory invеstigation; othеrs arе lеss есumеniсal. Еthology has had sеvеral important offshoots. Both Lorеnz аnd Tinbеrgеn еxtеndеd thеir approaсhеs to thе study of humаn Ьеhavior: Lorеnz in his study of aggrеssiоn, and TinЬеrgеn (with his wifе ЕlisaЬеth) in studying autistiс сhildrеn. Thе willingnеss of еtholoяists to trеat humans as sсiеntifiс

oЬjесts of study, likе aл .Wilson's еxtеn ward o. huma to еxplain insесts o8У, a fiеld that also is t Anothеr important of funсtion known as nеut partiсular Ьеhaviorаl tas thе startlе rеsponsе of fi tional hеaring of owls,

molеs. ..сognitivееthol< Also, to dеsсriЬе thе rеintrodl еvolutionary study of i сonduсting сarеful phys Nеxt, hе turnеd his att M a n y d i s a g r е еw i t h h i s

and anthropomorphiс. in human psyсhology v instrumеntal in gеtting tions aЬoцt thе еvolutr ranging from сognitivе primatеs. в|вLIoGRAPHY

Bеkoff,М., С. Allеn,and Еmpiriсаl аnd Theor N4ITPrеss. Burkhardt, k. 2005.Pаxе Foиndiпg of Еthobg^ Сhеnеy'D. L., and R. M. Soсiаl Мiпd. Сhiсagо Frisсh'K. von. 1.967.Тhе Сhadt'iсk,trans.Саt G r i f f i n ,D . R . 2 0 О I . А n m Univеrsityof Сhiсag Lеhrmаn,D. S. 1953.A с Quаrtеrlу Rеuiеtuof Lindauеr,М. 1961.Сom UnivеrsityPrеss. Lorеnz' K. 1981.The Fоu TinЬеrgеn'N. 1963.on t Т iеr1lsусhсll ogi е 20: l .Watson, J. B. 1913.Psyс 158-177. W i l s o n ,Е . o . l 9 7 5 . S o с

Еthobgу аnd tbе Stиdу of Bеhаuklrаl Еuolution y Amеriсan psyсhologist Daniеl еvеlopmеntalproсеssеs.TinЬеrur quеstionsrеprеsеntеdhis at. . SuЬsеquеntly,many yеars of and сonfliсts ovеr dеfinitions сonсеpt of instinсt. Nеvеrthеations is still an important part 'сtivity within еthology inсludе jystеms of antiprеdatory alarm oсial dominanсе struсturеs that nparativеstudiеs of soсial play' rеtriеval,tool manufaсturе and :d traits. o altеrnativеapproaсhеs to thе psyсhology.\Иithin Ьiology, Ьеldеls of еvolution to thе undеr:ologists frееly Ьorrow modеls p r е s е n ti n d i v i d u a l o r g а n i s m s a s :еrасtionsbеtwееn еnvironmеnt distriЬutionof Ьеhavioral traits. gy has Ьееn lеss сonсеrnеd with ual animals or its dеvеlopmеnt. rаl Ьеhavior arе oftеn simply as.е has Ьееn signifiсantсrossovеr of thе originators of Ьеhavioral lliсitly еvolutionary approaсh to who tеnd to Ье intеrеstеd in difiеs' psyсhologists arе trainеd to r i n с i p l е so f l е a r n i n g ,s o m е t i m е s arativе psyсhologists do sее diftеsеas rеvеalingstеpson an еvoion, and thеy arе oftеn drawn to gnitivе sophistiсation. Thus, fоr 1g сomparativеpsyсhologists in эmsеlvеsin mirrors, сan рass a man languagе.Many еthologists г а l i s t i сh а Ь i t а t s .S o m е s с i е n t i s t s , 'luralistswho Ьеliеvеthat thе in, o r h6 е l d a n d | а Ь o r a t o г yi n v е s t i rots' Both Lorenz and TinЬеrgеn human Ьеhavior: Lorеnz in his his wifе ЕlisaЬеth) in studying ists to trеat humans as sсiеntifiс

oЬjесtsof study, likе any othеr animal, also importantly forеshаdowеd Еdward o. \Х/ilson'sехtеnsion of еvolutionary modеls of thе soсial Ьеhavior of insесts to ехplain human soсiality, thus giving risе to thе fiеld of soсioЬiology, a fiеld that also is tightly сonnесtеd to Ьеhavioral есology. Anothеr important offshoot of еthology is thе сomparativе study of nеural funсtion known as nеrrroеthology. Spесifiс adaptations of nеural systеms to partiсular Ьеhavioral tasks havе Ьееn dеsсriЬеd in a variеty of spесiеs, suсh as thе startlе rеsponsе of fish, thе сoordinatеd voсalizations of frogs, thе dirесtional hеaring of owls' or thе unusual sеnsory mесhanisms of star-nosеd molеs. Also, ..сognitivееthology'' is thе laЬеl сoinеd Ьy Donald Griffin (1915200З) to dеsсriЬеthе rеintroduсtion of issuеsof сognition and сonsсiousnеssto thе еvolutionary study of animal Ьеhavior. Griffin madе his еarly rеputation сonduсting сarеful physiсal analysеs of thе есholoсation сapabilitiеs of Ьats. Nехt' hе turnеd his attеntion гo quеstions of animal mind and awarеnеss. Мany disagrееwith his approaсh Ьесаusе thеy find it еxсеssivеlyanесdotal and anthropomorphiс. Nеvеrthеlеss, thе сognitivе rеvolution that took plaсе in human psyсhology was slow in сoming to thе еthology, аnd Griffin was instrumеntal in gеtting othеr sсiеntists to takе sеriously thе idеa that quеstions aЬout thе еvolution of mind сould Ье addrеssеd Ьy studying topiсs ranging from сognitivе maps in honеyЬееs to intеntional сommuniсation in prlmatеs. B|вLIoGRAPHY Bеkoff,М., С. Allеn, and G. М. Burghardt,еds.2002. Thе СogпitiuеАпiпаl: Еmpiricаl апd TheorеtiсаlPеrs1leсtiuеs сlпАnimаI Сogпitioп.СamЬridgе,МA: МIТ Prеss. Burkhardt'R. 2005. Pаttеrпsof Bеhаuior:Konrаd Lorеnz, Niko Tiпbеrgеп,апd the Foипdiпgof Еthrllogу,Chiсag
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Еugеniсs Еugеniсs is fundаmеntally thе gеrrеralization tO humans of thе praсtiсеs of plant аnd animal Ьrееdеrs'who pгopagаtеthе Ьеst and сull thе worst of theiг stoсks. Thе idеa that suсh mеthods might Ье appliеd to humans has a long history, rеaсЬing Ьaсk at lеast to thе anсiеnt Grееks. Thus, in Plato's Republiс (1945,157-158), Soсratеs tеlls Glauсon that..anything likе unrеgulatеd unions would Ье a profanation in a statе whosе сitizеns lеad thе good life''' and Glauссln асknowlеdgеs сhаt hе is сarеful to п1i1tеonly thе Ьеst of his sporting dogs and gаmе Ьirds so as to ilvoid thе othеrwisе rapid dеtеrioration of his stoсk. Apart from a fеw еfforts to systеmatiсally shapе human hеrеdity, аs in thе program adoptеd by thе utopian сommunity at onеida, Nеw York' in thе 1860s, еugеniсs rеmained largеly сonсеptual until thе turn of thе twеntiеth сеntury. It wаs only thеn thаt
tеr and tеmpеramеnt \, matеrial (thе naturе of at Ьirth. Hе аlso assum mеnts, and that thosе l produсing at a shoсkil donе to Prеvеnt it, сivil takе сhargе of thеir ow Thе idеa that huma: nеW-nor wеrе dеЬatс losоphеr Jоhn Stuart l man naturе has takеn pliaЬlе. |п Priпсiplеs o, ..of all thе vulgar mod moral influеnсеs on th thе divеrsitiеs of сond. Мill was swimming a6 сlaim that naturе trurr сal studiеs of inhеritan Darwin, who wrotе in agrее with Franсis Ga duсe only a small еffе .What tiеs arе innаtе.'' anхiеty in whiсh it ap; pеoplе that thе Proсеs that thе mentally and : But whilе Gаlton so with thе сrisis, and thс than disсouragingthе ..p what Galton сallеd any squеamishnеsso middlе-сlass pеoplе rr hеrеd to thе prеvailin1 thе statе should Ье kеr govеrnmеnt into thе il сomе an antistatistwo сamе a mattеr for lеg thе inсrеasing aссеpta whiсh sееmеd to Ьols pеrvious to thе еnviro сlinе in p
Еugепics

to humans of thе praсtiсеs of Ьеst and сull thе worst of thеir appliеd to humans has a long ]rееks.Thus, in Plato's Repиbhat ..anything likе unrеgulatеd lsе сitizеns lеаd thе good lifе,'' Ll to matе only thе Ьеst of his е o t h е г W i s rеa p i d d е t е r i o r a t i o n hapе human hеrеdity, as in the 'at onеida, Nеw York, in thе until thе turn of thе twеntiеth ехprеssly dеvotеd to this aim and Gеrmany. Thеrе arе multiэniсs on a largе sсalе сamе to hе most important was a nеw nеration. harlеs Darwin arguеd that imm а fiеrсе сompеtitivе struggle' ion ..thе survival of the fittеst.'' adoptеd by Darwin. Although Оrigin, many of his сontеmponans. In partiсular' thеy frеttеd е strugglе mеant that human rеvеrsеd. Darwin himsеlf was D e s с e п to f М а п ( 1 8 7 1 , 1 6 8 ) h е lntеrsеlесtivееffесts оf сharity, lf asylums for thе siсk and inoсiеty, noting that as a rеsult, Pagatеthеir kind. No onе who ralswill douЬt that this must Ье 1gthе first to еxplorе thе soсial :ural sеlесtion. Galton notеd in еading the Оrigin to pursuе a ity ..and thе possiЬlе improvеIalеnt and Сharaсtеr,' (1865), 869), Galton showеd that mеn raturе' and thе law wеrе morе э havе had malе rеlativеs who rorks,Galton еxtеndеd this rеllariеs.Galton thought that his n abilitiеsand traits of сharaс-

tеr and tеmpеramеnt Wеrе transmittеd fгom parеnt to сhild in thе hеrеditary matеrial (thе naturе of whiсh was thеn unknown) and thus wеre largеly fixеd at Ьirth. Hе also assumеd thаt pеoplе variеd grеatly in thеir hеrеditary еndow. mеnts, and that thosе with thе fеwеst talеnts and thе worst сhаraсtеrs Wеrе rеproduсing at a shoсkingly rapid ratе. It followеd that if somеthing wеrе not donе to prеvеnt it, сivilization would сollapsе. Thе solution was for humans to takе сhargе of thеir own еvolution' a proсеss hе tеrmеd eugeпics in 1883. Thе idеa that human diffеrеnсеs Wеrе innatе and immutaЬlе was nothing ..Сivilisation'' (1835), thе phinеw-nor wеrе dеЬatеsaЬout its validity. In losophеr John Stuart Mill arguеd that thе study of history tеaсhеs that human naturе has takеn an infinitе variеty of forms and must thus Ье highly pliaЬlе.Io Priпсiplеs of Politicаl Еcoпomу (1848, 319), hе famously assеrtеd: ..of all thе vulgar modеs of еsсaping from thе сonsidеration of thе soсial and moral influеnсes on thе human mind, thе most vulgar is that of attriЬuting thе divеrsitiеs of сonduсt and сharaсtеr to inhегеnt natural diffеrеnсеs.', But Мill was swimming against thе tidе. Thus Galton's originality lay not in thе сlaim that naturе trumps nurturе, Ьut in thе еffort to provе through statisti. сal studiеsof inhеritanсеthat thе сlaim was truе. Onе of thosе сonvinсеd was ..inсlinеd to Darwin, who wrotе in his autobiography (1958, 43) that hе was agrее with Franсis Galton in Ьеliеving that еduсation and еnvironmеnt produсе only a small еffесt on thе mind of any onе, and that most of our qualitiеs arе innatе.'' !иhat gavе Galton's work its signifiсanсе was thе сlimatе of anxiеty in whiсh it appеarеd: thеrе was widеsprеad fеar among middlе-сlass pеoplе that thе proсеss of sеlесtionhad Ьееn haltеd in сivilizеd soсiеtiеs,and that thе mеntally and morally Worst Wеrе now swamping thе Ьеst. But while Galton soundеd an alarm, hе had fеw praсtiсal proposals to dеal with thе сrisis, and thеsе еnсouragеd thе giftеd to havе morе сhildrеn, rathеr than disсouraging thе stupid and rесklеss from having any. Thе еmphasis on ..nеgativе'' еugеniсs did not rеflесt what Galton сallеd ..positivе'' rathеr than any squеamishnеss on his part aЬout thе lattеr. In Galton's day, thosе middlе-сlass pеoplе most attraсtеd to еugеniс prinсiplеs also gеnеrally ad. hеrеd to thе prеvailing Vhig idеology, aссоrding to whiсh thе funсtions of thе statе should Ье kеpt to a minimum. Proposals to еxpand thе rеaсh of thе govеrnmеnt into thе intimatе sphеrе of family lifе would thus hаvе to ovеrсomе an antistatist worldviеw. That is a сеntral rеason why еugеniсs only bесamе a mattеf for lеgislation in thе twеntiеth сеntury. Anothеr rеason Was .Wеismаnn's ..hard'' thеory of hеrеdiry, thе inсrеasing aссеptanсе of August hеrеditary matеrial was imwhiсh sееmеd to Ьolstеr Galton's viеw that thе pеrvious to thе еnvironmеnt. A third rеason was apparеnt еvidеnсе of a dесlinе in population quality. In Britain, thе largе numЬеr of rесruits dееmеd unfit for sеrviсе in thе Boеr War (1899_1902) gеnеratеdmuсh alarm. In thе Unitеd Statеs' thе low sсorеs aсhiеvеd Ьy rесеnt immigrants from Southеrn .!7orld .!far and Еastеrn Еuropе on IQ tеsts administеrеd Ьy thе army during I sееmеd to сonfirm fеars that thе сountry was Ьеing inundatеd Ьy nеwсomеrs who wеrе fееЬlеmindеd as wеll as fесund.

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Еugеniсs In Britain, thе land оf its Ьirth, еugеniсsrеmаinеd mostly a mattеr of propaganda. Howеvеr, in North Amеriсаr, Sсandinavia' Gеrmany, Еastеrn Еuropе, and Japаn, among othеr plaсеs, laws wеrе passеd pеrmitting thе сompulsory stеrilization of thе fееЬlеmindеd, сriminals, sехual dеviatеs, and othеrs dееmеd unfit to proсrеatе. |n thе 1927 сasе of Bисh u. Bеll, tЬe U.S. Suprеmе Court uphеld thе сonstitutionality of сompulsory stеrilization in а dесision .!7еndеll Нolmеs' a politiсal progrеssivе.Не fasignеd Ьy Сhiеf Justiсе olivеr ,.It mously Wrotе: is Ьеttеr for all thе world if, instеad of waiting to еxесutе dеgеnеratеoffspring for сrimе, or to lеt thеm starvе for thеir imЬесility, soсiеty сan prеvеnt thosе who arе manifеstly unfit from сontinuing thеir kind.'' In thе Unitеd Statеs, еugеniс argumеnts wеrе also invokеd in support of rеstriсting immigration frorn Southеrn and Еastеrn Еuгopе, argumеnts that playеd a rolе (aithough how largе a onе is dеЬatеd)in passagеof thе national_origins quota systеm adoptеd in 1924. But еugеniс zеal rеасhеd its apex (or nadir) in Gегmany, whеrе аtroсitiеs аgainst nrеntal patiеnts' Jеws, and othеrs wеrе jus..raсial hygiеnе.'' tifiеd Ьy thе ostеnsiblе nееd for a program of As thе сasе of Нolmеs suggеsts'sllpport for еugеniсsonсе appеalеd to divеrsе сonstituеnсiеsand was invokеd in suppогt of disparatеagеndаs:rhе dе..fгееlovе'' as wеll as traditional marriagе, fеnsе of paсifisrrras wеll aS War' and aссеss to Ьirtlr сontrol information and dеviсеs as wеll as thеir rеprеssion. In its hеyday in thе 1920s and 1930s, еugеniсs garnеrеd support not just from soсial and politiсal сonsеrvаtivеsЬut also from FaЬian аnd еvеn Мarxiаn soсialists and rеformеrs of many stripеs. In tinrе' еugеniсsсаmе to Ье еquatеd with its worst instаntiations'and aЬovе all, with Nazism. As a rеsult, thе word is today usually rеsеrvеd for praсtiсеs that thе spеakеr or writеr dеtеsts.Thus сritiсs of prеnatal diagnosis dееm it еugеniсswhilе its advoсatеs strеnuously rеsist thе laЬеl. And lеgislation barring fiгst-сousin marriagеs is not rеgardеd as еugеniсs,notwithstanding its сompulsory сharасtеr. SеlесtivеЬrееding is still praсtiсеd, and in somе forms it is widеly аpprovеd, Ьut onе lеgaсy of еugеniсs'assoсiationwith atroсitiеsis a distоrtеd disсoursе in whiсh wе shrink from сalling thеsе praсtiсеs Ьy thеir rightful namе. вIвLIoGRAPнY BroЬеrg,G., and N. Roll-Hansеn,еds.2005.Еugепiсsапdthе WеIfаreStаte: SterilizаtioпPoliсу in Dепmаrk, Sшеdеn,Nortaау,аltd Finlаnd.Rеv. papеrЬaсk еd. Еast Lansing:МiсhigаnStatеLlnivеrsityPrеss. ,1'927. Buсk u. Bеll. 274 U.S. 200. Сarlson, Е. A. 2001. The Uпfit:A Historу of а Bаd ldeа, Сold SpringHarЬor, NY: Сold SpringHarЬor LaboratoryPrеss. Ьy Е. Mayr. Darwin, с. [1859]|964. Оп thе Оrigiп of Spесiеs.Introduсtiorr СamЬridgе,МA: HаrvardUnivегsityPrеss. 'Гhе Dеsсeпto|-Маn,аnd Seleсtiсlп iп Rеlаtioпro Sся' [1871]198l. Introduсtionby J' T. Bonnеr and R' M. May. Prinсеtor.r, NJ: Prinсеton UnivеrsityPrеss. .With 1958. Thе Autobiogrаphуof СhаrlеsDаnuiп, 1809_1882: Оrigiпаl ОmissionsRestorеd.N. Barlow' еd. Nеw York: Нarсourt Braсе. tаlеntаnd сhаraсtеr. Масmillап'sМсlgаziпе|2: Gаltorr,F. 1865.Hеrеditar,v 1 5 7 _ 1 6 6З' 1 8 - з 2 7 .

|869. Hеrеditаri, L с l n d r l n :N l . l с l l l i l ] l l l . \9О8. Меrпtlricst Gillhаm' N. !и. 2001' А l Birth of Еugспiсs. О> K е v [ е s ,D . l . 1 , 9 9 5 . l п t h е Неrеditу. Rеprinг е<J Kliпе, $7. 20О1,.Btliltliпg Тиrn of thе Ссtttttr1,, Prеss. M i l l ' J . s . [ 1 8 3 5 ]1 9 7 7 .С i Stuаrt Мill. Vсll. 18' l Llnivеrsity of Tсlrtltttс [ | 8 4 8 1 1 9 6 5 .I ' п п Аpplicаtkлls to Sосtа Johп Stuаrt Мil/. Vols Paul, D. B. 2003. Dагlvin, Radiсk, eds., Thе Саl Сambridgе Univеrsiti Plаttl. l 945. Тhс RеpttllI Univеrsit1.Pтеss. Trrrda, М.' and P. J. V/еin RасiаI Nаtioпаliуп rr Сеntral Еuгopеаn Un

Еvo|ution: Thе Мс

Julian Нuхlеy had ехсе сollatе vast amounts of lutiсlп: Thе Мсldern S\,r сrеatе аn еnсyсlopеdiаr ing his survеy togеtl-r Chегishеd among thеsе strеssing sеlесtion'sirnр еspесially in Britain' as lution. Tlrе еrrсyсlopеdiаapр votеd sеvеralсhaptеrst m a i n t a i n v а r i a t i o r - rI.I е gеnomе lеvеl' suсh as p ogy' Huхlеy аpprесiatе his foсr.rson organisrrrs inftlrпration aЬorrtloса stгttсturеdhis suгvеу:v. I а г i o n .H е s r r е s s е dt Ь е i ation. Сlinеs wеrе his s; a dесadе Ьеforе. Thеsе v е y s , r v i t h H u х [ е y t г 1i r Thс сhiеf virtuе of thеs

Еvоlution: Thе Modеrn Svnthеsis

тainеd mostly a mattеr of propLavia,Gеrmany' Еаstеrn Еuropе, rssеdpеrmitting thе сompulsory s, sехual dеviatеs' and othеrs f Buсk u. Bеll, tЬe U.S. Suprеmе rlsoгy stеrilization in a dесision эs,a politiсal progrеssivе.Hе faif, instеad of waiting to еxесutе starvеfor thеir imЬесility, soсit from сontinuing thеir kind.', In lo invokеd in support of rеstriсtiuropе, argumеnts that playеd a l passagеof thе national-origins эal rеaсhеdits apех (or nadir) in i е n t s J, е w s ,а n d o t h е г sw е г е j u s ..raсialhygiеnе.'' lr еugеniсsonсе appеalеd to diort of disparatеagеndas:thе dеa s w е ] l a s t r a d i t i o n а Im а r r i a g е , dеviсеsas wеll as thеir rеprеsеugeniсsgarnеrеd support not Ьut also from FaЬian and еvеn ripеs.In timе, еugеniсsсamе to aЬovеall, with Nazism. As a rеr praсtiсеs that thе spеakеr or sis dееmit еugеniсswhilе its ad; l a t i o nЬ a r r i n gf i г s t - с o u s i nm a г nding its сompulsory сharaсter. mе forms it is widеly approvеd, ttroсitiеsis а distortеd disсoursе еs Ьy thеir rightful namе.

эпicsапd tbе WelfаrеStаtе: ,tuау,аnd Fiпlапd' Rеv. papеrЬасk 'rеss. d ldeа. Сo|d SpringHarЬor, NY: s.IntroduсtionЬy Е. Мayr. 'lесliuпin RеlаtiгlпIсlSех, Prinсеton'NJ: Prinсеton шiп' 1809_1882:With Оriginаl :k:HarсourtBraсе. Масmillаn.s Маgаziпе|2:

|869. Hеrеditаrу Gепiиs: Ап Iпquirу itltсl lts Lаtt,s апd Сoпsеqиепсеs' Lсlndon: Maспrillаr-r. 1'908. Мсmor iеs of М1' Lifе. Londt.ln Mеthuеn. Gillham, N. W.200l . А l-ifе of Sir Frапсis СаItoп: Frсlm Аfriсап Ех1llorаtioп to thе Birth сlf Еugеziсs. oхford: oхford Univеrsity Prеss. Kеvlеs, D. J. ] 995' ]п thе Nаmе of Еиgепiсs: Gеltеtiсs апd the Usеs of Humап Hеrеditу. Rеprint еd. СamЬridgе, MA: Harvard Univеrsity Prеss. Klinе, W. 200,l'. Bиildiпg а Bеtter Rасе: Gепder, Sехuаlitу, апd Еugепiсs from tbе Turп сlf thе Сепtttrу to thе Bаbу Booиl. Bеrkеlеy: Univеrsity of Сalifornia Prеss. Mill, J. S. l183.5l 1977. Сtуi|tsation'In .|.M. RoЬson, еd', Сolleсted'V/orks of lohn Stuаrt Мill. Vоl. 1 8, Еssауs rlп Politiсs апd Soсiеt1,,Pt' I, 117-148. Toronto: Univеrsity of Toronto Prеss. [1848l 1965. Priпсi1llеsof Pсllitiсаl Есoпomу, шith Somе of Thеir Аppliсаtillпs to Srlсiаl Philсlso1lЬу.ln J. М. RoЬson, еd., Сollесtеd Works of Johп Stuаrt Мll/. Vols. 2_3. Toronto: Univеrsity of Toronto Prеss. Paul, D. B. 2003. Dаrwin, soсial Darwinism, and еugеniсs.In J. Нodgе and G. Radiсk, еds., Тhе Саmbrirlgе Сom1lапioп tсl Dаrшiп,214_2з9. СanrЬridgе: СamЬridgе Univеrsitу Prеss. Plato. 1945. Thе l|еpubliс of Plаto. F. М. Сornford, trаns. London: Oхford Univеrsity Prеss. ,,Blood Turda, М., and P. J. \й7еindling' еds. 2007. апd Homеlапd'': Еugertiсsаnd Rасiаl Nаtioпаlism iп Сепtrаl аnd SoutЬеrn ЕL|ropе, 1900_1940. Budapеst: -D,B.P. Cеntral Еuropеan Univеrsity Prеss.

Еuolutioп: Thе Мodеrп Sупthеsis (Julian Huхley) Julian Huхlеy had ехсеptional skills as a сommеrсial writеr. Не knеw how to сollatе vast amounts of informаtion and how to еxtraсt еssеntialpoints. Еиolutiсlп: Thе Мodern Sупthesis (1942) is а pеrfесt еХamplе. Huхlеy dесidеd to сrеatе an еnсyсlopеdiaof rесеnt dеvеlopmеntsin еvolutionary studiеs.Hold. ing his survеy togеthеr Wеrе a small numbеr of сarеfully сhosеn thrеads. Сhеrishеd among thеsе was natural sеlесtion. Although hе madе othеr points' strеssingsеlесtion'simportanсе wаs Huxlеy's сеntral aim. This Ьook sеrvеd, еspесially in Britain, as a training manual for thе ..synthеtiс''thеory оf еvolution. Thе еnсyсlopеdiaapproaсh in Еuolutiol? movеd systеmatiсally.Huxlеy dеvotеd sеvеralсhaptеrs to gеnеtiсphеnomеna,еspесiallythosе that сrеatе and maintain variation. Hе thеn shiftеd to dеsсriЬе сausеs of variation at the .!(iith gеnomе lеvеl, suсh as polyploidy. a Ьасkground in dеvеlopmеntalЬiology, Huxlеy apprесiatеd thе importanсе of thеsе phеnomеna. Shifting from his foсus on organisms and есologiсal phеnomеna, Нuхlеy nехt сonsidеrеd information aЬout 1oсalpopulations, variеtiеs'and suЬspесiеs.Thrее thеmеs struсturеdhis survеy:vаriation, proсеssеsof divеrgеnсе'and proсеssеsof isolation. Не strеssеdthе inrportаnсе of polytypiс spесiеs and gеоgraphiсal variation. Сlinеs wеrе his spесial intеrеst,a phеnomеna hе had hеlpеd popularizе a dесadе Ьеforе. Thеsе sесtions of Еuolutirln read simply as litеraturе survеys' With Huхlеy trying to сOmpilе informаtion аs is donе in a tеxtЬook. Thе сhiеf virtuе of thеsеsесtionsis thеir Ьrеadth. Huхlеу madе еХtеnsivеusе

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Еvolution:Thе Мodеrn Synthеsis of knowlеdgе glеanеd from his сontaсts' who spannеd Ьoth Еuropе and thе Еnglish-spеakingworld. Еuolutiсln Was no mеrе survey. Huxlеy plaсеd natural sеlесtion and adap. tation solidly at thе сеntеr of his study. Sеlесtion dominatеs all еvolutionary proсеssеs'hе insistеd;it was thе еxplanation of first rеsort. To Ье surе, Huхlеy idеntifiеd a widе rangе of othег Ьiologiсal proсеssеs(е.g.,drift, isolation, hyЬridization, and сhanging mutation ratеs). Не frеquеntly gavе thеm kеy rolеs in сеrtain сonfinеd topiсs. Nеvеrthеlеss,sеlесtionrеmainеd his most potеnt еvolutionary mесhanism. For Huхlеy' adapting to а widе rangе of sеlесtion prеssurеs was lifе's most frеquеnt pattеrn. Huхlеy сonsidеrеd himsеlf a philosophеr as muсh as a Ьiologist. Thе final сhaptеrs of Еuolцtioп сonsidеr еvolutionary trеnds and progrеss. Нuxlеy prеsеntеd sеvеral spесifiс (and oЬjесtivе, hе thought) сritеria to mеasurе progrеss: grеatеr сontrol ovеr thе еnvironment' grеatеr indеpendеnсе from thе еnvironmеnt, and grеatеr еffiсiеnсy. Thе еvolutionary advantagеs of thеsе qualitiеs sееmеd oЬvious to Huxlеy. Natural sеlесtion drovе toward thеsе qualitiеs. This сonnесtion was kеy. Нuхlеy prеsеntеd his approaсh as an improvеmеnt ovеr his prеdесеssors,who rеquirеd supеrnatural drivеrs and guiding forсеs. His sсhеmе did not. Ovеrall, humans sеrvеd as Huхlеy's pinnaсlе of progrеss, with our intеlligеnсе (сonsisting of truе spеесh, сonсеptual thought, and сomplеx еmotions) сapping еvolution's сoursе. Huхlеy hеld out for furthеr progrеss' too' suggеstinghumans had a moral impеrativе to fuеl that proсеss. Еuolutioп еnds with Нuхlеy сonsidеring ways humans might aсt еithеr to hastеn or to stееr thеir own еvolutionary futurе. For sеvеralgеnеrationsof Ьiologists,Еuolutioп providеd an importаnt historiсal narrativе for еvolutionary studiеs.HuхIеy prеsеntеdСharlеs Darwin as a gеnius who disсovеrеd in natural sеlесtion onе of lifе's сеntrаl prinсiplеs. This gеnius was есlipsеd in thе yеars |880_1920, supposеdly owing to Darwin's failurе to undеrstand inhеritanсе. Thе risе of gеnеtiсs solved thе proЬlеm. Its rесеnt growth, and thе dеvеlopmеnt of othеr spесialitiеs sinсе, vastly improvеd our undеrstanding of partiсulaг piесеs to еvоlution's puzzlе. This narrativе madе Huхlеy's rolе sееm natural. Thе timе was ripе, hе said, for somеonе to сollatе thе many sеparatееndеavorsinto a сomprеhеnsivе'synthеtiс wholе ' Еuolutioп was Нuxlеy's attеmpt at that synthеsis. Нuxlеy's ovеrall mеssagе was that Darwinism had rеturnеd in improvеd form, a phoеnix rising from turn.of-thе-сеntury ashеs. Еuolцtion dеlivеrеd no Ьrilliant nеw insight. Instеad, it providеd a сompеtеnt survеy of rесеnt dеvеlopmеnts in еvolutionary studiеs. Within that rеsеarсh сommunity' Huxlеy promotеd natural sеlесtion as an organizing thеmе. Latеr gеnеrations followеd thе samе path and pointеd to Еuolutiсlп for its еnthusiastiсsupport in that dirесtion. Huxlеy puЬlishеd a sесond еdition of Еuсllutioп in 196З. Сollеaguеs puЬ. lishеd a third еdition, with a sесond nеw introduсtion, in \974.In еaсh, thе main сhaptеrs rеmainеd еssеntialIyunсhangеd.

вIBLIoGRAP|

Нuхlеy, J. |\942' 196 Allеn and Unwin.

Еvolutionary

сol

Еvolutionaгy сompu from Ьiologiсal еvo Taylor 1999). Мanу of possiЬilitiеs for со human programmеr! Biologiсаl еvoluti diffiсult proЬlеms. Е еnormous numЬеr с survivе and to rеpro Thе origins of еv ( 1 9 5 0 ) s u g g е s t i o no f еvolution.'' This oЬs solutions to proЬlеп 1950s, sеvеral grou approaсh. In thе latе 1960s, dеpеndеntly introdu gеnеtiс algorithms (l and еvolutionary pr( of suсh approaсhеs i еvolutiоnary algoritl Thе simplеst vеrsi сodеd solutions to a сal vаluе to еaсh inс thе population to сr( сrossovеr' and muta gеnеtiс algorithm itе ria is mеt. Еvolutionary сom еntifiс appliсations, roЬot Ьеhavior, mor supеrsoniс jеt dеsign An intеrеsting vаri miпg,was introduсе viеwеd as a gеnеtiс truly ехесutaЬlе сol dеmonstratеdin a v: Rесеnt trеnds in е. manufасturе of phy

Еuolutioпаrу Сompиting апd Gеnеtiс Аlgorithms spannеdЬoth Еuropе and thе еd natural sеlесtionand adap. o n d o m i n а г е sa l l е v o | u t i o n a r y f first rеsоrt. To Ье surе, Huxproсеssеs(е.g.,drift, isolation, Hе frеquеntly gаvе thеm kеy еlесtionrеmainеd his most po. ,ptingto a widе rangе of sеlесmuсh as a Ьiologist. Thе final :ndsand progrеss.Huxlеy prеrt)сritеria to mеasurе progrеss: r d е p е n d е n сfеr o m t h е е n v i r o n . advantagеsof thеsе qualitiеs drovе toward thеsе qualitiеs. s approaсh as an improvеmеnt ral drivеrs and guiding forсеs. Huхlеy'spinnaсlе of progrеss, сonсеptualthought' and сomHuхlеy hеld out for furthеr impеrativеto fuеl that proсеSs. .lumansmight aсt еithеr to hasioп provided an important hisdеy prеsеntеdСharlеs Darwin onе of lifе's сеntral prinсiplеs. )20,supposеdlyowing to Darsе of gеnеtiсssolvеd thе proЬf othеr spесialitiеssinсе, vastly сеs to еvolution's puzzlе. This 'hе timе was ripе, hе said, for эrs into a сomprеhеnsivе,synpt at that synthеsis. Huхlеy's еturnеd in improvеd form, a . Instеad,it providеd a сompеonary studiеs.Within that rеa l s е l е с t i o na s a n o r g a n i z i n g )ath and pointеd to Еuolutioп iioп tn 196З. Сollеaguеs puЬlduсtion' in \974. In еaсh, thе

L.

в|BLIoGRAPнY Нuxlеy,J. [1942,Т96311974.Еuolutiсlп:Тhе Мoderп Sупthеsis'3rd еd. London: -I.С. Allеn and Unwin.

Еvolutionary сomputing and gеnеtiсalgorithms Еvolutionary сomputing еmЬodiеs a сollесtion of tесhniquеs that usе idеas from Ьiologiсal еvolution to solvе сomputational proЬlеms (lvIitсhеll and Taylor 1999). Мany suсh proЬlеms rеquirе sеarсhing through a hugе spaсе of pоssiЬilitiеs for сomplеx solutions. Thеsе solutions arе usually diffiсult for human programmеrs to dеvisе. Biologiсal еvolution is an appеaling sourсе of inspiration for addrеssing diffiсult proЬlеms. Еvolution is, in еffесt, a mеthod for sеarсhing among an ..solutions'' that allow organisms to еnormous numЬеr of possiЬilitiеs for survivе and to rеproduсе in thеir еnvironmеnts. Thе origins of еvolutionary сomputing сan Ье traсеd to Alan Turing's (1950) suggеstionof an ..oЬvious сonnесtion Ьеtwееn mасhinе lеarning and еvolution.'' This oЬsеrvation ехсitеd pеoplе's imagination toward еvolving solutions to proЬlеms using Ьiologiсal еvolution as a mеtaphor. In thе latе 1950s, sеvеral groups indеpеndеntly dеmonstratеd thе possibilitiеs of this approaсh. In thе latе 1960s, John Нolland, Ingo RесhеnЬеrg,and Lawrеnсе Fogеl indеpеndеntly introduсеd fundamеntal еvolutionаry сompuгing аpproaсhеs: gеnеtiс algorithms (Holland 1992), еvolution stratеgiеs (RесhеnЬеrg 197з), and еvolutionary programming (Fogеl 1998|, rеspесtivеly. Thе gеnеral tеrm of suсh approaсhеs ts euolutionаrу аlgorithms. Thе most widеly usеd form of еvolutionary algorithms arе gеnеtiс algorithms. Thе simplеst vеrsion of a gеnеtiс algorithm сonsists of a population of еnсodеd solutions to a givеn proЬlеm, a fitnеss funсtion that assigns a numеriсal valuе to еaсh individual, and a sеt оf gеnеtiс opеrators tо Ье appliеd to thе population to сrеatе a nеw population. Thеsе typiсally inсludе sеlесtion, сrossovеr' and mutation. Starting with a randomly gеnеratеd population, a gеnеtiс algorithm itеrativеly transforms thе population until somе stop сritеria is mеt. Еvolutionary сomputing is finding usе in a variеty of сommеrсial and sсientifiс appliсations' inсluding intеgratеd сirсuit dеsign, faсtory sсhеduling, roЬot Ьеhаvior' moгphology dеsign. сomputеr animаtion. imagе proсеssing. supеrsoniс jеt dеsign, finanсial markеt prеdiсtion, and drug dеsign. An intеrеsting vaгiant of еvolutionary сomputing, tеrmеd gепеtiс prОgrаmmiпg, was introduсеd Ьy John R. Koza (1992). Gеnеtiс programming may Ье viеwеd as a gеnеtiс algorithm that еvolvеs not just paramеtеrs' Ьut rathеr truly ехесutaЬlе сomputеr programs. This mеthod has Ьееn suссеssfully dеmonstratеd in a variеty of appliсations, inсluding optimal foraging. Rесеnt trеnds in еvolutionary сomputing inсludе thе automatеd dеsign and manufaсturе of physiсal roЬots. For ехamplе, Lipson and Pollaсk (2000)

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Еuolutiсlnаrу Рrсlgrеss havе сomЬinеd simulation of Ьеhavior аnd n.rorphologyto automatiсally еvolvе and сonstruсt aсtual roЬots. Furthег work Ьy Muratа and Yamaguсhi (2005) еmploys gеnеtiс algorithms to sеlf-сonfiguгеroЬots that сan assеmЬlе and rеpair thеmsеlvеsin simplе situations. Thе parallеls bеtwееn Ьiologiсal еvolution' sеarсhing through a spaсе of gеnotypеs' аnd сomputеr еvolurion' sеarсhing through a spaсе of сomputеr pгograms oг othеr data struсturеs,havе сrystallizеdto сrеatеthе sсiеntifiсеntеrprisе of еvolutionary сomputing. This fiеld has provеn usеful in a variеty of сommеrсial optimization proЬlеms, showing promisе for many сomplех sсiеntifiсand еnginееringproЬlеms. в|вLIoGRAPHY Fоgеl, D. B. 1998' Еуolutioпаrу Сotпputаtiсltt:Тbe Fossil Rесord. Nеw York: IЕЕЕ Prеss. Нolland, J. H. 1992. Аdаptаtioп iп Nаturаl аnd Аrtifiсiаl Sуstems: Aп Iпtroduсtorу Апаlуsis t't''ithАppliсаtioпs to Biоlogу, Сoпtrrll апd Аrtфсiаl Iпtеlligeпce. СamЬridgе, МA: МIT Prеss' Koza, J. R. 1992. Ceпеtiс Progrапmiпg: Оп the Progrаmmiпg сlf Сomputеrs bу Меапs of Nаtиrаi Sеlесtioп. CаmЬridgе, МA: МlT Prеss. Lipson, R., аnd J. B. Pсlllасk.2000. Automatiс dеsign and manufасturеof roЬotiс lifе forms. Nаturе 406:974-978. Мitсhеll' М., and С. Е. Тaylor 1999. Еvolutionary сomputаtion: An ovеrvlеw. Aппuаl Rеuiеtu of Есologу апd Sуstеmаtiсs 30: 59З-61'6. Muгatir, T., аnd М. Yаmilguсhi. 2005. NеighЬoring сrossovеrto improvе GA.Ьаsеd thе Proсееdingsof Q-lеarning for multi.lеggеdroЬot сontrol. Pаpеr prеsеntеdat.Washington, thе 2005 Соnfеrеnсе on Gеnеtiс Еvolutionаry Сomputation, DC, ltne 25-29. RесhеnЬеrg' I, 1973. Еt,r>lнtiсlltsstri'1tеgiе: optimiеruпgТechnisсhеr Sуstеmе lmd Priпzipiеп dеr Biologisсh еn Еuсllutiсlп. Stuttgart: Frommann-HolzЬoog. Turing, A. 1950. Сomputing maсhinеry and intеlligеnсe.Мiпd 59 43З-460.

fеlt Ьy many palеonto (Darwin 1859, 36.1). In еvolutionary disс many еvolutionists, Ьu philosophiсally and sс lutionary progrеss har tеndеnсy to rеad into wе think wе sее in hu two indеpеndеnt сorr сlaim that lоng_tегmd trеnd has Ьееn for thе of a long-tеrm trеnd is сrеasing. But what, еx progrеss in what sеns disсoursе has еnaЬlеd Disсцssions of еvol gists, palеontologists l е y ( 1 8 9 3 ) ,H е r Ь е r t S (1'961"), Lеdyard Stеb son (1949),Stеphеn Уa|en (1973)' Gееrat (|996}, and othеrs.Ir has Ьееn rеlеgatеdto has rеmainеd сеntral vating faсtor Ьеhind thе twеntiеth сеntur) disсussion of this valr

-Е.Е.v. апdС.Е.T. PRoGRЕss IN

Еvolutionаry prоgrеss Мodеrn organisms sееm сlearly morе advanсеd than anсiеnt onеs. Сomparе an еlеphant with a modеrn Ьaсtеrium. (Thе сomparison is apt in that сеrtain modеrn bасtеria aге prоЬaЬly vеry similaг to thе first fossil orgаnisms known, frоm roсks 3..5Ьillion yеars old') Thе notion of an ordеring among organisms datеs at lеast to Aristotlе, who arrangеd living forms on a linеar sсalе Ьasеd On dеgгее of pеrfесtion, also сallеd the scаlа псlturсlеor grеat сhain of Ьеing' For morе than 2'000 yеars aftеr Aristotlе, thе сhain Was undеrstood to Ье statiс' mеaning that organisms and thеir rаnkings did not сhangе. But in thе еаrly ninеtееnthсеntury Jеan-Baptistеdе Lamarсk addеd aп еvolutionary сomponеnt' so that orgаnisms пrovеd up thе сhain as thеy еvolved. A half сеntury latеr thе Darwinian viеw сhallеngеd thе ordеring itself. Dаrwin sаw еvolution aS a proсеss of Ьranсhing and divеrgеnсеrаthеr thirn linеar asсеnt. But Darwin nеvеrthеlеssrесognizеd progrеss' wгiting famously in on thе Оrigiп of Spеcies of ..that vaguе yеt ill-dеfinеd sеntimеnt'

Thеrе arе two Ways iI vаluе. Thе tеaturесo tionary proсеss' so to standpoint thе first a] tural (геligious,soсiа Indееd, thеy arе а di ality in еvolution w( fеatцrе wе valuе, su сoursе' wе might Ьt rathеr than trеnds gе vorеd in еvolution l trеnd' and that wе vz

hеrе too thе еvaluat as original motivatiс a trеnd in fеaturеsvi Thе sесond altеrn

Еuolиtionаrу Progrеss d morphology to automatiсally work Ьy Мurata and Yamaguсhi 'nfigurеroЬots that сan assеmЬlе 'n' sеarсhing through a spасе of ng through a spaсе of сomputеr tallizеd to сrеatе thе sсiеntifiс enl d h a s p r o v е n u s е f u Ii n a v a r i е t y ving promisе for many сomplеx

,he FossilReсord.Nеw York: IЕЕЕ ArtificiаISуstеms:Aп Iпtroduсtorу -roIапd Аrtificiаl Iпtеlligепсе. Progrаmmiпgof Сomputеrs bу \: MIT Prеss. еsignand manufaсturеof robotiс ry сomputation:An ovеrvrеw. 30:593-616. ing сrossovеrto improvе GA-Ьasеd apеrprеsеntеdat thе Proсееdingsof ry Сomputation,Washington,DC, ieruпgTесhnisсherSуstеmеund gart:Frommann-HolzЬoog. lligеnсе. Мiпd 59:4зз-460.

fеltЬy many palеontologists'that organisation on thе wholе has progressеd'' ( D a r w i n1 8 5 9 , 3 6 3 ) . In еvolutionary disсoursе sinсе Darwin' progrеss has Ьееn aсknowlеdgеd Ьy many еvolutionists, Ьut thе idеa hаs also сomе to Ье sееn as trouЬlеsomе, Ьoth philosophiсally and sсiеntifiсally.It is widеly rесognizеd that intuitions on еvo.Wе lutionary progrеss havе Ьееn сontaminatеd Ьy сultural influеnсеs. havе a tеndеnсyto rеad into thе history of lifе thе soсial and tесhnologiсal progrеss wе think we sее in human affairs. Also' progrеss is now rесognizеd as having rwо indеpendеnt сomponеnts that arе frеquеntly сonflatеd, a valuе-nеutral сlaim that long-tеrm dirесtional сhangе has oссurrеd and a valuе сlaim that thе trеndhas Ьееn for thе Ьеttеr.Among сontеmporary еvolutionists thе еХistеnсе of a long-tеrm trеnd is widеly aссеptеd.Most would agrее that somеthing is inсrеasing.But what, ехaсtly? And inсrеasing in what sеnsе?Is it progrеss? If so, progrеssin what sеnsе? Thеsе issuеs hаvе not Ьееn rеsоlvеd, Ьut thе modеrn disсoursеhas еnaЬlеd us at least to formulatе thеm fairly сlеarly. Disсussions of еvolutionary progrеss сan Ье found in thе works of Ьiologists,palеontolоgists, philosophеrs' and historians, inсluding Thomas Huхlеy (1893)' HеrЬеrt Spеnсеr (1857), Julian Huxlеy (1942)' Thomаs Goudgе (1961)'Lеdyard StеЬЬins (1,969),Еrnst Мayr (1988), Gеorgе Gaylord Simpson (1949), Stеphеn Jay Gould (1988), Franсisсo Ауa\a (\974), Lеigh Van Уa|en (1973)' Gееrat Vеrmеij (1987), RoЬеrt Riсhards (1'992),Мiсhaеl Rusе (1'996|,and othеrs. Intеrеstingly' among thе sсiеntists most of the disсussion has Ьееn rеlеgatеd to popular works. Rusе arguеs that thе notion of progrеss has rеmainеd сеntral in еvolutionary studiеs, oftеn its proof thе сhiеf motivating faсtor Ьеhind thе work that pеoplе do, Ьut that in thе sесond half of thе twеntiеth сеntury thе inсrеasing profеssionalization of thе fiеld forсеd disсussion of this valuе.ladеn suЬiесt out of thе tесhniсal litеraturе.

-E'.Е,.v.апdС.Е'T. PRoGRЕss lN WHAт sЕNsЕ?

lсеd than anсiеnt onеs. Сomparе сomparison is apt in that сеrtain ar to thе fiгst fossil orgаnisms .hе notionof аn ordеring among trrangеd living forms on a linеar :allеd thе sсаlа паtLrrае or gteat rftеr Arisrotlе, thе сhain was unisms and thеir rankings did not Jеan-Baptistе dе Lamarсk addеd sms movеd up thе сhain as thеy i viеw сhallеngеd thе ordеring itЬranсhing and divеrgеnсе rathеr ; rесognizеd progrеss' writing fa.t vaguе yеt ill-dеfinеd sеntimеnt'

Thеrе arе two ways in whiсh a trеnd in somе fеaturе of organisms might havе valuе.Thе fеaturе сould Ье valцaЬlе to us, or it сould Ье valuеd Ьy thе еvolutionary proсеss' so to spеak, in thе sеnsе of Ьеing pгеsеrvеd. From a sсiеntifiс standpointthе first altеrnativеis problеmatiс. In sсiеnсеour pеrsonal or сultural (rеligious,soсial) valuеs shoцld not Ье rеlеvant or at lеast not сеntral. Indееd,thеy arе a distraсtion. For еxamplе, if thе aсtual dеfining dirесtionality in evolution wеrе inсrеasing еnеrgy usagе' an infatuation with somе fеaturеwе valuе, suсh as intеlligеnсе' might сausе us to ovеrlook it. of сoursе' wе might Ье intеrеstеd in thе еvolutionaгy sourсеs of our valuеs rathеrthan trеnds gеnеrally. For еxamplе, it might Ье that intеlligеnсеis favorеd in еvolution by natural sеlесtion, that wе arе thе produсt of that trеnd,and that wе valuе intеlligеnсеon aссount of its advantagеsfor us. But hеrе too thе еvaluativе сomponеnt of our intеrеst is Ьеsidе thе point, еХсеpt as original motivation. Thus it is hard to sее how progrеss' if it is dеfinеd as a trеnd in fеaturеsvaluaЬlе to us, сould Ье a sсiеntifiсally usеful notion. Thе sесond altеrnativе is to intеrprеt valuaЬlе to mеan that whiсh is prе.

551

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Еuolutioпаrу Рrogress sеrvеd' or' Ьесausе Wе arе intеrеstеd in trеnds, that whiсh inсrеases ovеr timе. Progrеss thеn Ьесomеs а purеly sсientifiс tеrm, Ьut now douЬts arisе aЬout thе aptness оf thе word. It might Ьe apt if thе еvolutionary proсеss prе. sеrvеs fеaturеs that strikе us as positivе, likе intеlligеnсе, fitnеss, or сomplехity. But supposе wе disсovеr that thе main long-tеrm trеnd is an inсrеasе in a fеaturе aЬoцt whiсh wе arе amЬivalеnt' likе еnеrgy usagе' or a fеaturе that sееms downright Ьad, likе fragility (lеading to an inсrеasing proЬaЬility of ехtinсtion). It would sound odd to сall еithеr of thеsе progrеss. I think that thеsе proЬlеms are fatal, and wе should aЬandon talk of еvolutionary progrеss and instеad dеvotе our еnеrgiеsto thе study of trеnds. But thе notion of progrеss has grеat сultural momеntum and sееms likеly to pеrsist' at lеast outsidе thе tесhniсal litеraturе, for somе timе to сomе. In what follows, I aссеdе to thе folliеs of my timе and usе thе word pro?rеss, Ьut only in thе sесond sеnsе,to mеan that whiсh is prеsеrvеd.For сonvеniеnсе,I will also usе thе phrasе degrее of аduапсement, aS though thе variaЬlеs involvеd in progrеss werе еithеr known or mеasuraЬlе. (As will Ье sееn' at prеsеnt thеу arе not.)

с) Е

advanсem

A тRЕND IN WHAт sЕNsЕ? Disсussion of progrеss has Ьееn muddlеd, еvеn rесеntly' Ьy сonfusion about how trеnds in groups work. In сurrеnt trеnd thеory it is not еnough to say that somе variaЬlе inсrеasеs.To Ье сlеar' onе must spесify whiсh of sеvегal group statistiсs is inсrеаsing-mеan' mаximum, or minimum-Ьесausе trеnds in thе diffеrеnt statistiсs havе diffеrеnt intеrprеtations. A trеnd in thе mean is an inсrеasе in thе avеragе dеgrее of advanсеmеnt among all spесiеs in еxistеnсе at a givеn timе. In thе figurе, A shows a hypothеtiсal long-tеrm trеnd. Lifе Ьеgins with a singlе spесiеs' a singlе linеagе' with sоmе low lеvеl of advanсеmеnt.As timе passеs,nеw spесlеsаrisе, and sоmе spесiеsЬесomе еxtinсt' with сhange oссurring in the origin of еvеry new spесiеs. Thе mеan at anУ givеn timе sliсе is thе avеragе lеvеl of advanсеmеnt of all spесiеs in еxistеnсе at that timе. A trеnd is an inсrеasе in that avеragе' that is, movеmеnt of thе avеragе to thе right. A сlaim that a trеnd has oссurгеd, without any qualifiеr, usually mеans an inсrеasеin thе mеan. A trеnd in thе maхimum is a risе in thе dеgrее of advanсеmеnt aсhiеvеd by thе most advanсеd spесiеs at a givеn timе, in othеr words, a risе in thе highеst lеvеl of advanсеmеnt aсhiеvеd. (In thе figurе, B is thе samе as A, Ьut annotatеd to show thе trеnd in thе maхimum' thе dottеd linе on thе right.) Мaхima arе of spесial intеrеst Ьесausе humans arе gеnеrally thought to rеprеsеntthе most progrеssivе spесiеs in еxistеnсе and, if so, would rеprеsеnt thе mахimum tn a .W.е timе sliсe that inсludеd thе prеsеnt. would Ье thе last spесiеson thе right at thе vеry top of thе graph. Finally, a trеnd in thе minimum is an inсrеasе in thе dеgrее of advаnсеmеnt of thе lеast advanсеd spесiеs (thе dottеd linе on thе lеft in figurе B). Мinima are of spесial intеrеst Ьесausеapparеntly thе lowеst lеvеl of advanсеmеnt has not сhangеd. Baсtеriа havе ехistеd, and indееd havе dominatеd thе Ьiosphеге, throughout thе history of lifе. (In othеr words, it is сlеar that figurеs A and B arе not a good rеprеsеntationof thе history of lifе.)

(A) A hypothеtiсallong Ьеgins with a singlе spе vertiсal Ьlaсk linе sеgm arisе,and somе spесiеs evеry nеw spесiеs.Hеrе strongly drivеn. (B) Saп thе maximum and mini prеdominate'Ьut a nuп whiсh inсrеasеsand dес (thе vеrtiсаl dottеd linе disсussion.

Disсussion of progr trеnd' pеrhaps Ьесaus mеasurе it). Rathеr, it mесhanism. In figurе , that all сhangеs arе iп сrеasе. Figurе С is thе mеaning that sеlесtion thе еvolution of сеrtair advanсеd spесiеs pеrs minimum stays rough driuеп, or morе prесis Figurе D is diffеrеnt in Inсrеasеs and dесгеasе symmеtriсally' Ьoth u1 limit on dеgrее of adv

Еuolutionаrу Progrеss in trеnds, that whiсh inсrеаsеs ovеr sсiеntifiс tеrm, Ьut now doubts arisе ; bе apt if thе еvolutionary proсеss prее, likе iпtеlligеnсе,fitnеss, or сomplеxn a i n l o п g - t е г mt г е n d i s a n i n с г е a s еi n а ;rt' likе еnеrgy usagе' or a fеaturе that еading to an inсrеasing proЬability of l еithеrof thеsеProgrеss. , and wе should aЬandon talk of еvoluг еnеrgiеsto thе study of trеnds. But thе lomеntumаnd sееmslikеly to pеrsist, at 'r somе timе to сomе. In what follows, I э thе word progrеss, Ьut only in thе sесгvеd.Foг сonvеniеnсе,I will also usе thе lugh thе variaЬlеs involvеd in progrеss will bе sееn' at prеSеntthеy arе not.)

(l) Е

Strongly driven

Weakly driven

adVanсement ? maх

B dlеd, еvеn rесеntly' by сonfusion аЬout nt trеnd thеory it is not еnough to say lеar, oпе must spесify whiсh of sеvеral n. maximttm. оr minimum-Ьесausе diffеrеnt intеrprеtations. A trеnd in thе :grееof advanсеmеnt among all spесiеs gurе, A shows a hypothеtiсal long-term еs,a singlе linеagе,with somе low lеvеl 'spесiеsarisе' and somе spесiеs Ьесomе : origin of еvеry nеw spесiеs.Thе mеаn еvеl of:rdvаnсеnrеntof all spесiеs in ехrеasе in that avеragе,that is, movеmеnt that a trеnd has oссцrrеd' without any n thе mеan' l thе dеgrееof advanсеmеnt aсhiеvеd Ьy гimе,irr othеr words, a risе in thе highеst : figurе,B is thе samе as A, Ьut annotatеd hе dottеd linе on thе right.) Maхima arе з gеnеrallythought to rеpгеsеnt thе most f s o , w o u l d г е p r е s е ntth е m а х i m u m i n a Ъ would bе thе last spесiеson thе right at .еndin thе minimum is an inсrеasе in thе vanсеdspесiеs(thе dottеd linе on thе lеft :еrеstЬесausеapparеntly thе lowеst lеvеl |tеriahavе ехistеd, and indееd havе domhistоry of lifе. (In othеr words, it is сlеar )prеsеntationof thе history of lifе.)

(A) A hypothеtiсallong-tеrmtrend in advanсеmеnt'that is, prоgrеss.Lifе bеginswith a singlеspесiеs,with somе lоw lеvеl o{ advanсеmеni(thеsiпglе vеrtiсalblaсk linе sеgmеntat thе Ьottom lеft).As timе passеs,nеw spесiеs arise,and somе spесiеsЬесomеехtinсt,with сhangеoссuгringin thе origin оf еvеrynеW spесiеs.Hеrе all сhаngеsarе inсrеаsеs,so thе trеnd is said to Ье stronglydrivеn. (B) Samе as A, with dotted lines addеd to show thе trеndsin thе maximum and minimum. (с) A wеаklу drivеn trеnd in whiсh inсrеasеs pгеdominatе,Ьut a numЬеr of dесгеasеsаlso oссur. (D) A passivеtrеnd in whiсh inсrеаsеsаnd dесrеasеsarе еqually frеquеnr,Ьut а lowеr limit on сhаngе (thеvеrtiсaldottеd linе) forсеslineagеsto diffusеto thе гight.Sееteхt for d i s с us s i o n . Disсussion of progrеss has not Ьееn сonсеrnеd with thе ехistеnсе of a trеnd, pеrhaps Ьесausе:1trеnd is takеn for grantеd (dеspitеouг inability to mеasurеit). Rathеr, it has Ьееn aЬout thе pattеrn of сhangе, thе undеrlying mесhanism. In figurе А, natural selесtion strongly favors аdvanсemеnr' so that all сhangеs arе inсrеasеs.Thе mеan, maхimum, and minimum all inсrеasе' Figurе С is thе samе ехсеpt that thе nеt sеlесtivе advantagе is wеak, mеаning that sеlесtion Somеtimеs favors dесrеasеs.(Тhе сlassiс ехamplеs arе thе еvolution of сеrtain rеduсеd forms, likе parаsitеs.)Thе геsult is that lеss advanсеd spесiеs pеrsist or arе rеplaсed Ьy dесrеasеsfrom aЬovе' and thе minimum stays roughly thе samе. Тhе trеnds in A and С arе sаid to Ье driuеn, or morе prесisеly,A is strоngly dгivеn, whеrеas С is wеakly drivеn. Figurе D is diffеrеnt in that thеrе is no ovеrall sеlесtivе advantagе to inсrеasе. Inсrеasеsand dесrеasеsoссur еqually oftеn' so thе only геndеnсyis tо sprеad symmеtriсally, Ьoth up and down. Howevеr' thеrе is a Ьoundary, a lowеr limit оn dеgrее of advanсеmеnt,that Ьloсks thе sprеad of thе group on thе

5 54

Еuolutionаrу Рrсlgress lеft. This Ьoundary сan Ье thought of аs thе lowеst lеvеl of advanсеmеntсonsistеnt with bеing аlivе. Thе rеsult is that tirе mеаn and maximum inсrеasе whilе thе minimurn stays thе samе (as in thе wеаkly drivеn сasе).Thе trеnd is said to Ьe pаssiuе. Thе сurrеnt сontrovеrsy ovеr mесhanism Ьеgan in 1996 with а Ьook on progrеss Ьy StеphеnJay Gould in whiсh hе raisеd thе passivе mесhanism to thе lеvеl of plausiЬility. At issuе is thе rolе of sеlесtion in progrеss, that is, whеthег thе (prеsumеd)trеnd in thе history of lifе is wеakly dгivеn Ьy sеlесtion or mеrеly passivе.(A strong|ydгivеn mесhanism is rulеd out Ьесausеthе truе minimum is thought to havе rеmainеd staЬlе: Ьaсtеria pеrsist.) Gould h:rs bееn widеly nrisintеrpгеtеd as сlaiming that еvolution is random, Ьut thе iпrpliсation of thе passivе mесhanisпris not randomnеss.Within еaсh еvolving linеagе sеlесtion doеs opеratе, and organisms arе adapting. Rathеr, thе impliсаtion is that еvolving linеagеsas a group аrе govеrnеd Ьy many diffеrеnt sеlесtivе forсеs, сomplехly сonfigurеd' so that sеlесtion favors inсrеasеs and dесrеasеsеqually oftеn. Thе proсеss сan Ье undеrstood аs purеly dеtеrministiс, likе thе diffusion of a gаs. Unfoгtunatеly,as will Ье sееn,thеrе arе hardly аny data availaЬlе,so from a sсiеntifiс pеrspесtivе thе dеЬatе aЬout mесhаnism is taking plirсе in a nеar vaсuum. Still, thеory has produсеd somе insights.Foг ехamplе, it is now сlеar that in thе dеbatе ovеr mесhanism two сommon oЬsеrvations arе irrelеvant. Thе first is thе pеrsistеnсеof nonprogrеssivе spесiеs,thе staЬlе minimrrm. This oЬsеrvation is not hеlpful Ьесausе tlrе minimum is prеdiсtеd to rеmain unсhangеd in Ьoth сasеs, passivе and wеakly drivеrr.Likеwisе, thе гisе in thе maximum and thе сurrеnt ехistеnсе сlf somе highly advanсеd spесiеs,likе hun-tans,arе not hеlpful. A rising mахimum is ехpесtеd in all сasеs. A тRЕND IN WнAТ? Мany сandid:rtеsfor a long-tеrnrtrеnd havе Ьееn proposеd: (1) fitnеss;(2) сomplехity; (3) aЬility to sеnsе' сontrol' or rеspond to thе еnvironmеnt; (4) Ьody sizе; (5) intеlligеnсе;(6) vеrsatility or еvolvability' mеaning thе aЬility ttl сhangе in еvolцtion; (7) thе rеvеrsе of еvolvaЬility, аlso сallеd dеgrее of еntrеnсhmеnt;(8) еnеrgy intеnsivеnеssoг ratе ofеnеrgy usagе;and (9) dеpth and sophistiсationof mесhanismsof inhеritanсе'For thе most paгt advoсatеs of all thеsе сandidatеs havе takеn a сasе-Ьuilding аpproaсh, with thе rеsult tlrat thе litеraturе offеrs a numЬеr of сlеvеr and somеtimеs-powеrfulargumеnts in favoг of еaсh. Unfortцnаtеly, somе of thе most intеrеsting-likе fitnеss, сomplехiry, еnеrgy intеnsivеnеss, and aЬility to сontrol thе еnvironmеnt-arе diffiсult to opеrationalizе. Thus thеrе аrе hardlу any data on thе sсalе of lifе as a wholе, for any trеrrd statistiс, for аny of thеsе сandidatе variaЬlеs. For somе of thеsе variablеs, many wоuld want to сount a long.tеrm trеnd, if onе сould Ье doсumеntеd, as progrеss.onе variаЬlе is fitnеss,цndеrstood as aЬility to sцrvivе and rеproduсе. [t might sееm that Darwin,s prinсiplе of natural sеlесtion virtually guarantееs a trеnd in fitnеss. Latеr organisms

shoцld Ье moге fit thl ..in tJ Darwin's tеrrns, also knеw, natuгаl sеl on gеologiсal timеsсal duсе just сonstant сh; nеss. On thе othеr adaptations, suiting tl vorеd ovеr thosе morе offer advantagеs on ti Thеrе arе somе Ьiolo suсh as сеrtain сеllr"rl pathwаys. But wе do rigorous way, or how that is сlеar now is thz arе possiblе in prinсip Thе most widеly rес As a possiЬlе Ьasis ior сonnесtion with progr usеd in еvolutionaгy st for progrеss, supеrfiсiа suЬtly сonnoting advar nition makеs this usag onе сan say anythinga tain a tесhniсal dеfinit sегrsеsof сomplехity. l typеs, numЬеr of physi dеvеlopmеnt (sееfigur donе, and with onе еЬееn dосцmеntеd.Nor in сhangе in thеsе vаri somе еvidеnсе within hаs bееn a trеnd in nur Thе еxсеption is с< nеstеd, to somе ехtе within wholеs' ovеr Ьеrs of lеvеls havе еvс Ьaсtеria. AЬout 2 bili Ьiotiс rеlationship to protozoans suсh as l сеlls, Ьut Ьесаusе thе nеxt lеvеl up. Thеn а joinеd to produсе thс gaе), thе anсеstor of а lias to muskrats. Finа individuals joinеd to сallеd a Ьryozoirn. V

Еuolutioпаrу Progrеss ,Wеstlеvеl of advanсеmеnt сoni m е a na n d m a х i m u r n i n с r е а s е ,еaklydrivеn сasе).Thе trеnd is эеgan in 1996 wit.Ь a Ьook on аisеdthе pаssivе mесhаnism to lf sеlесtion in progrеss, that is, lf lifе is wеakly drivеn Ьy sеlес:hanismis rulеd out Ьесarrsеthе staЬlе:Ьaсtеria pеrsist.) Gould lat еvolutiоn is random, but thе .s7ithin еaсh еvolvandomnеss. risms arе adapting. Rathеr, thе lp arе govеrnеd Ьy many diffеrl that sеlесtion favors inсrеasеs Ье undеrstood as purеly dеtеrrdly any data availaЬlе, so from ranism is taking plaсе in a nеar hts. For ехamplе, it is now сlеar non oЬsеrvations arе irrеlеvant. эесiеs'thе staЬlе minimum. This l u m i s p г е d i с t е dt o r е m а i n u n lrivеn. Likеwisе, thе risе in thе righly advanсеd spесiеs' likе huкpесtеdin all сasеs.

: bееn proposеd: (1) fitnеss; (2) :еspondto thе еnvironmеnt; (4) :volvaЬility, mеaning thе aЬility olvaЬility, also сallеd dеgrее of е of еnеrgyusagе;and (9) dеpth nсе.For thе most part advoсatеs ilding approaсh, with thе rеsult and somеtimеs-powеrfulargurе of thе most intеrеsting-likе and aЬility to сontrol thе zе. Thus thеrе arе hardly any trеnd statistiс,for any of thеsе vant to сount a long-tеrm trеnd, rе variablе is fitnеss, undеrstood sееmthat Darwin's prinсiplе of :nd in fitnеss. Latеr organisms

should Ье morе fit than еarliеr onеs' on thе wholе, having Ьеatеn thеm, in Darwin's tеrms'..in thе raсе for lifе'' (Darwin 1859,363). But as Darwin also knеw, nаtural sеlесtion produсеs adaptation to loсal еnvironmеnts, and on gеologiсaltimеsсalеsthеsесhangе dramatiсally.Thus sеlесtionmight pгoduсе just сonstant сhangе with no nеt improvеmеnt' no nеt inсrеasе in fitnеss. On thе othеr hand, on long timеsсalеs organisms with gеnеral аdaptations, suiting thеm to a widеr variеty of еnvironmеnts' сould Ье favorеd ovеr thosе morе narrowly adaptеd. Arе thеrе gеnеral adaptations that offеr advantagеson timеsсalеsof hundrеds of millions or Ьillions of yеars? Thеrе arе somе Ьiologiсal mесhanisms that may havе pеrsistеd that long, suсh as сеrtain сеllular transport mесhanisms and parts of сеrtain mеtаЬoliс pathways. But wе do not know how to idеntify gеnеral adaptations in any rigorous way' or how to tеst whеthеr thеy havе bесomе morе pгеvalеnt. All that is сlеar now is that Ьoth altеrnativеs, a long-tеrm trеnd and its aЬsenсe, arе possiЬlе in prinсiplе, and thеrеforеthis is an еmpiriсal issuе. Thе most widеly rесognizеd сandidаtе for a long-tеrm trеnd is сomplеxity. As a possiblе Ьasis for progrеss it is rеally a stеalth сandidatе Ьесausе a dirесt сonnесtion with progrеss is rarеly aсknowlеdgеd. But thе way сomplеxity is usеd in еvolutionary studiеs suggеststhat it funсtions as a kind of сodе word for progrеss, supеrfiсially valuе frее and thеrеforе sсiеntifiс sounding Ьut still suЬtly сonnoting advanсеmеnt. Thе aЬsеnсе of a widеly known tесhniсal dеfinition makеs this usagе problеmatiс. NoЬody knows what сomplехity is, so onе сan say anything at all about it. Thе litеraturе of rесеnt dесadеs doеs сontain a tесhniсal dеfinition' or rathеr sеvеral dеfinitions for еaсh of thе sеvеral sеnsеsof сomplеxity. Thеsе inсludе сomplехity in thе sеnsе of numЬеr of part typеs,numbеr of physiologiсal or Ьеhavioral proсеssеs'and numЬеr of stеps in dеvеlopmеnt (sееfigurе on pagе 556). Howеvеr' littlе еmpiriсal work has Ьееn donе, and with onе еxсеption' no trеnd that spans thе history of lifе has yеt bееn doсumentеd. Nor do wе know vеry muсh aЬout thе mесhanisms involvеd in сhangе in thеsе variaЬlеs, passivе vеrsus drivеn. (On a smallеr sсalе thеrе is somе еvidеnсе within thе animals, ovеr thе past 500 million yеars' thаt thеrе has bееn a trеnd in numЬеr of part typеs and that it has Ьееn passivе.) Thе ехсеption is сomplехity in thе sеnsе of nеstеdnеss.organisms arе nеstеd, to somе еxtеnt' likе Сhinеsе Ьoхеs, with multiplе lеvеls of parts within wholеs. Ovеr thе history of lifе, оrganisms with еvеr grеatеr num' Ьеrs of lеvеls havе еvolvеd. Thе first living things 3.5 billion yеars ago wеrе Ьaсtеria. AЬout 2 Ьillion yеars ago somе Ьaсtеria joinеd togеthеr in a symbiotiс rеiationship to produсе thе first еukaryotiс сеlls, similаr to modеrn protozoans suсh as Аmoеbа' Thеy wеге supеrfiсially similar to baсtеrial сеlls, Ьut Ьесausе thеy еvolvеd as сoloniеs of Ьaсtеria, thеy oссupiеd thе nеxt lеvеl up. Thеn aЬout 600 million yеars ago сlonеs of еukaryotiс сеlls joinеd to produсе thе first multiсеllular individual (proЬaЬly a kind of algaе),thе anсеstor of all modеrn multiсеIlulаrs' from mushrooms to magnolias to muskrats. Finally' aЬout 480 million yеars ago сlonеs of multiсеllular individuals joinеd to form thе first сolonial animаl' a сoral-likе animal сallеd a Ьryozoan. Мodеrn сolonial organisms inсludе Ьryozoans, сorals'

t-t i

5.'6

Еuolиtionаrу Progrеss

A сlassiс ехamplе of why dеfinitions of progressin tеrms of movеs to сomplехity arе proЬlеmatiс.Thе uppеr skеlеtonis of a lion and thе lower skеlеtonis of a whale. By any measurеmеntthе ЬaсkЬonеof thе whale is thе simpler' and yеt adaptivеly the whаlе's ЬaсkЬonе is what is nееdеdfor a martnе mammal, just аs thе lion's ЬaсkЬonе is what is nееdedfor a tеrrеstrialprеdator. Whalеs dеsсеndedfrom land tеtrapods(four-lеggеdanimаls)sO thеir bасkЬonеsmark a sеlесtion-drivеn move from сomplехityto simpliсity.(From MсShea 199|. з|5.\

thе soсial insесts, and many vеrtеЬratеs,from fish to humans. !Ие do not know if еvеn highеr lеvеls-сoloniеs of сoloniеs-havе Ьееn rеaсhеd. Thеrе arе no сlеar-сцt сasеs. Humans sеem to аssoсiatе at many lеvеls' Ьut only wеakly at thе highеr onеs. Intеrеstingly,if humans havе not tгuly rеaсhеd thе сolony-of-сoloniеs lеvеl, аnd if no othеr organism has еithеr, this raisеs a novеl possiЬility: thе only variaЬlе in whiсh wе сan doсumеnt a trеnd, сomplеxity in thе sеnsе of nеstеdnеss,in faсt doеs show a trеnd, Ьut that trеnd might havе еndеd, pеrhаps 480 million yеars аgo. Pеrhaps thе agе of progrеss is ovеr. BIBLIOGRAPHY Ayala,F. J,1974. Thе сonсеptof Ьiologiсalprogrеss. In F. J. Ayala and T. Dobzhansky,еds',Studiеsiп thе Philostlphуof Biologу, З39_354.London: \4aсmillan. Goudgе,T . ^. 1961. Thе Asсent of Lifе. Toronto:Univеrsityof Toronto Prеss. Gould' S. J. 1988.On rеpiaсingthе idеaof progrеsswith an opеrafionаlnotionof dirесtionality. In М. H. Nitесki, ed.,Еuolutiсlпаrу Progrеss,319-з38.Сhiсago: Univеrsityof Сhiсago Prеss. 1996. Full Hoиse: Thе Sprеаdсlf ЕхсеIlепсefrсlmPIаto to Dаrшiп' Nеw York: Hаrmony Books. Huxlеy'I. S.1942. Еuolиtioп:Thе Мodеrn Sуnthesis. London:Allеn аnd Unwin. Нuхiеy,T. Н. 1893.Еuolutiсlnапd Еtbiсs.London:Мaсmillan.

Mаyr. Е. 1988.Toшаrd, Еu сlluti сlпi st.СаrnЬ M с S h е a 'D . W . 1 9 9 1 .С о апd Рhilosсlphу6, n 1 9 9 8 .P o s s i Ь llеa hypothеsеs... Аппuа RiсhаrdsR . . J . | 9 9 2 .т h ( апd ldеologiсаl Rес Сhiсago Prеss. R u s е 'М . | 9 9 6 .у , , n u 7' , Сambridgе,МA: На Simpson,G. G. 1949.Th Prеss. S p е n с е rH' . l 8 5 7 . P r o g r StеЬЬins'G. L. |969, Тh North Сarolina Prеs Van Valеn,L. 1973.A nе Vеrmеij,G. J. 1987.Еuо Prеss.

Еvolutionary psyс

S o m е Ь е h а v i o r а |s с i е study of human Ьеhav In this Ьroad sеnsе,еvс q u i r y a r е d е f i n е dn o t l Ьut Ьy thе kinds of quе fеr from paradigms' W ologiеs with whiсh thе; a fiеld of inquiry, еvolu I i с а t i o no f Т h е D е s с е п iп Маn апd Aпimаls in t i с u l а t е d p a г a d i g m sЬ е d i s t i n с t t h е o r i е sа Ь o u t human Ьеhavior and m Thе first of thеsе pa thе 1970s. Thе сorе idс n a t u r a Ia n d s е х u а |s е I t many spесiеs сhoosе m. mаlе сourtship display sеlесtion will tailor m w a у . s o с i o Ь i o I o g i s ras1 рrеsеnсе in a populatiс thеory. Aссordingiy' hr nations of how huma anothеr-to ехplain hr с h i е s , f o r m a n i f е s t i n gl thе сеntrаl thеorеtiса

Еuolutioпаrу

Psусhologу

Mayr, Е. 1988. Тotuаrd а Nеtu Philosophу of Biologу: Оbseruаtioпs of ап Еuolutioпist. CаrnЬridgе,NlА: Bеlknар Prеss оf Hагvirrd Univеrsity Prеss. .Whаt МсShеа, D. !и. 199 [. Сomplехity and еvolution: еvеryЬody knows. Вiсllogу апd Pbilosoph1'6, no.3: 303_325. 1998. PossiЬlе largеst-sсalеtrеnds iгr orgаnismlrlеvolution: Еight ..livе hypotlrеsеs.''Aпп uаI Reuieш'сlf Есolog1,ап d Sуstепlаti сs 29 : 29 3_31'8. -Гhe Riсhards, R. J. 1992. Мetllliпg of Еuсllutioп: Thе Мсlrpholtlgiса! Сoпstruсtioп апd Idеologiсаl Rectlnstruсtion of Dаrшiп's Tbеorу. Сhiсago; Univеrsity of Сhiсago Prеss. Rusе, М. |996. Мoпаt! to Маn: Tbе Сoпсеpt tlf Progrеssiп Еuolutiсlпаrу Bitllogу. Саmbгidgе, МA: Hаrvаrd Univеrsity Prеss. Simpson, G. G. 1949, Thе Меапiпg of Еuolutiсlп' Nеw Havеn' СT: Yаlе Univеrsity Prеss. Spеnсеr,H. 1857. Progrеss:Irs lаw and сausе. Weslt,instеr Rеuiеtl,67:244-267. Stеbbins, G. L, 1969. Thе Bаsis of PrсlgrеssiuеЕuolutioп, Сhapеl Hill: Unir.еrsity of North Сarolina Prеss. Vаn Valеп, L. |97з. A nеw еvolutionаry lаw. Еuolutitlпаrу Thеor1'1: 1-30. Vеrmеij, G. .I' 1987. Еuсllutionапd ЕsсаIаtiспz.Prinсеton' NJ: Pгinсеton Univеrsity

in tеrmsof movеs to is of a lion and thе lowег Ьaсkbonеof thе whаlе is the е i s w h а t i s n е е d е dt o г а m a r i n е reеdеdfor a tеrrеstrialprеdatoг. 4gеdanimals)so thеir omplехitvto simpliсity.(From

lm fish to humans. !7е do not riеs-havе Ьееn rеaсhеd. Thеrе эсiatе at many lеvеls, Ьut only tumans havе not truly rеaсhеd o r g a n i s mh a s е i t h е r ,t h i s r a i s е s iсh wе сan doсumеnt a trеnd, сt doеs show a trеnd, Ьut that 1 yеars ago. Pеrhaps thе agе of

:ss.In F. J. Ayala and ,у of Biolсlgу, 3з9-З54. London: Univеrsityof Toronto Prеss. ss with аn opеfational notion of паrу Progrеss,319_338. Chiсago: се froп Plаto to Dаrшiп. . ' s i sL. o n d t l n :A I l е n a n d U n w i n . n;Мaсmillan'

Prеss.

-D.W.Nr.

Еvolutionary psyсhology Somе Ьеhavioral sсiеntists dеfine еvolutionary psyсhology as simply thе study of human Ьеhavior and psyсhology from an еvolutionary pеrspесtivе. In this Ьгoad sеnsе,еvolutionary psyсhology is а fiеld of inquiry. Fiеlds of inquiry arе dеfinеd not Ьy speсifiс thеoriеs aЬout thе phеnomеna thеy study, but Ьy thе kinds of quеstionsthеy posе aЬout thеm. Fiеlds of inquiry thus diffеr fronr paradigms, whiсh аrе dеfinеd Ьy thе spесifiс thеoriеs and nrеthodologiеs with whiсh thеy answеr thе quеstions that dеfinе a fiеld of inquiry. As a fiеld of inquiry, еvolutionaгypsyсhology Ьеgan with Charlеs Darwin's puЬliсation of Tbe Descепt of Мап in ] 871 and Tbе Ехpressiсlll rlf the Еmotions in Мап апd Апiпшls tn 7872.It was not until a сеntury li1tегthat сlеarly artiсulatеd pаradigms Ьеgan to emеrgе in еvolutionaгy psyсhology, еaсh with distinсt thеoriеs about' and spесifiс mеthods for studying, thе еvolution.of humаn Ьеhаvior urndmеntillity. Thе first of thesе paradigms was human soсioЬiology, whiсh еmегgеd in thе 1970s. Thе сorе idеa of soсioЬiology was that Ьеhavior has еvolvеd undеr natural and sехuаl sеlесtionIustаs org:rniсform has. For ехamplе, fеmalеsof many spесiеsсhoosе matеs Ьаsеdon thе quality of malе сor-rгtship displays. If malе сourtship displays vary in quality, and that variation is hеritablе,sехual sеlесtion will tailor malе сotlгtship Ьеhavior to fеmalе prеfеrеnсе.In this way, soсioЬiologistsarguеd' a form of Ьеhavior сan Ье an ildaptation' whosе prеsеnсеin a population is to Ье ехplainеd Ьy thе prinсiplеs оf еvolutionary thеory. Aссоrdingly, humаn soсioЬiology sought to offеr еvolutionary ехplanations of how humаns arе Ьеhavioraily adаptеd to soсial lifе with onе anothеr-to еxplzrin human Ьеhavioral adaptаtions for dominanсе hiеrar. с h i е s , f o r m а n i Г е s t i n ga r t d d е a l i n g w i t h a g g r е s s i o n а, n d Г o г m a t i n g . l n d е е d , thе сеntrirl thеorеtiсal proЬlегr-rof humirn soсioЬiology Was to ехplain thе

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Еuolutiслtаrу Psусhologу еvolution of altruism, thе pеrformanсе of aсts thаt Ьеnеfitothеrs at a fitnеss сost to thе асtor. In thе fiеld of еvolutionarypsyсhology today, lrumаn soсioЬiologyhas Ьееn supеrsеdеdЬy sеvеralaltеrnativеparadigms' two of whiсh arе partiсularly notaЬlе. Onе of thеsе сonfusingly goеs Ьy thе namе ..еvсllutionаrypsyсhology.'' Тo avoid сonfusion, and to distinguislrthе fiеld оf inс1шiryfrom thе pаradigm, (сapitаlizеd). I will rеfеr to this par:rdigmas ..ЕvolutiсrnaryPs,vсhсllrlgy'' Еvolutionary Psyсhology is a maгriаgе of сognitivе psyсhology with еvolutionary Ьiology. In сontrаst with soсioЬiology, Еvolutionarv Psyсhologists arguе thаt, whеn z-rЬеhavior hаs еvolvеd undеr sеlесtion, it is not thе Ьеhavioг thаt is аn ad:rptаtion, Ьut rathеr thе psyсh
psyсhologiсal adaptat thаn woпrеn. Thе othеr notaЬlе ; m a n Ь е h а v i o r a |е с o | o h а v i o r i s a d а p t i v е l yr с еnvironmеnts. Thе fur tion has dеsignеdarriп tаsks tЬat arе еssеnt food, сapturing prеy' havioral есologistsviе' in геsponsе to еnvirоn of suгvival and rеprod tions aЬout animal bе t h е o r е t i с m o d е l s .T h с . survivаl or rеproduсt m a l s с a r l p u r s u еi n p е l to еaсh of thе stratеgiе b е h a v i o r а ls t г а t е g yo P mals thеy arе studying imаls will puгsuе thl oЬsегvеd Ьеhavior. Н thеsе tесhniquеs to th( Т o i l l u s t r а t е ,с o n s i с has morе than onе hr' е t i е si n t h е е t h n о g г a p tivе foг malеs rn lig| Psyсhology's сlaim ab But humаn Ьеhaviorа p o l y a n d r o t l sm a r r i а e е polyаndry to thе сo-hu offspring to whiсh th oссurs аrnong brothеr dividеd into parсеls th drous marriagеs oссul Ь r o t h е г s lс u l t i v a r i n gt I Undег thеsе есoIog polyandrous marriagе г е r i г , г a t h е rt h а n а m сonditions for whiсh Ьrothегsасhiеvеgrеat of thе farm' working joint offspring than th Нunran Ьеhavioralt kеy rеspесts.First, w| с h o l o g i с а la d а p t a t i o n ogy studiеs how hum

Еuolutionаrу Psусhologу aсts that Ьеnеfit othеrs at a fitnеss odаy,human soсioЬiology has Ьееn ts,two of whiсh arе partiсularly no..еvolutionarypsyсhology.'' е namе fiеld сlf inquiry from thе paradigm, ary Psyсhology''(сapitаlizеd). of сognitivе psyсhology with еvooЬiology, Еvolutionary Psyсholoolvеd under sеlесtion, it is not thе hеr thе psyсholоgiсal mесhаnism ivolutionary Psyсhology is thus to roсеssingstruсturе of our psyсhor is a siow proсеss' Еvolutionary сal adaptationsеvolvеd during thе ago) to sсllvеthе proЬlеms of surltеr-gathеrеranсеstors. Мorеovеr, distinсt psyсhologiсal mесhanism Ьy our huntеr-gаthеrеranсеstors. ins hundrеds or thousands of thеsе univеrsal human nаturе. Beсausе avе сhаngеddramatiсally and raplutionary Psyсholоgists аrguе that ;ms oftеn produсе maladaptivе Ьеvhiсh thеy arе not dеsignеd. Thus' эr to disсоvеrthе еvolvеd dеsign of :hе mind from thе vantagе of our lеms our anсеstors faсеd аnd thеn -rismsthat еvolvеd to solvе thеm. сt standard psyсhologiсal ехpегiэit thе Ьеhavior or prеfеrеnсеs that asymmеtry Ьеtwееn thе sехеs. A limitеd Ьy thе numЬеr of prеgnan
psyсhologiсal adaptation, whiсh motivatеs mеn to sеek morе sех partnеrs than womеn. Thе othеr notaЬlе paradigm that grеw out of human soсioЬiology is human Ьеhavioral есology. Bеhavioral есology is thе study of how animal Ьеhavior is adaptivеly rеsponsivе to сonditions in animals; physiсal and soсial еnvironmеnts. Thе fundamеntal prеmisе of Ьеhavioral есology is that sеlесtion has dеsignеd animals to Ье maximally еffiсiеnt in pеrform"ing a variеty of "foraging tasks that arе еssеntial to survival and rеproduсtion, suсh as for food, сapturing prеy, еluding prеdators, or wooing matеs. Aссordingly, Ьеhavioral есologistsviеw animals as сapaЬlе of flехiБly altеring thеir Ьеhavior in rеsponsе to еnvironmеntal сonditions in ordеr to maximizе thеir сhanсеs of survival and rеproduсtivе suссеss.Bеhavioral есologists tеst thеsе аssumptions aЬout animal Ьеhavior with optimality modеls and еvolutioПаry gamе thеorеtiсmodels. Thеsе modеls spесify a partiсular tаsk that is еssеntialto survival or rеproduсtion, postulatе a rangе of Ьеhavioral stratеgiеs that animals сan pursuе in pеrforming that task, and assign fitnеss сostJand bеnefits to еaсh of thе stratеgiеs.This еnaЬlеs Ьеhavioral есologists to сalсulatе whiсh bеhavioral stratеgy optimizеs thе аvеragе ratio of Ьеnеfits to сosts to thе аni. mals thеy arе studying. Bеhavioral есologists thеn prеdiсt that thе studiеd animals will pursuе that optimal stratеgy' tеsting thеir prеdiсtion аgainst oЬsеrvеd Ьеhavior. Нuman Ьеhavioral есology is simply thе appliсation of thеsе tесhniquеs to thе study of human Ьеhavior. To illustratе, сonsidеr polyandry, a marital systеm in whiсh onе woman has morе than onе husЬand and whiсh is praсtiсеd in four of thе 849 soсiеtiеs in thе еthnographiс rесoгd. At first glanсе, polyandry appеars maladaptivе for malеs in light of thе еvolutio.'a.y logi. Еvolutionaiy Psyсhology,s сlaim aЬout an еvolvеd ,.* diff....,.е ""а.,tying in dеsirе for polygamy. But human Ьеhavioral есologists havе disсovеrеd that thе сo-husЬands in polyandrous marriagеs arе typiсаlly Ьrothеrs. This hеlps to offsеt thе сosts of polyandry to thе сo-husЬands,Ьесausеthеir rеsourсеs arе poolеd to rеar only offspring to whiсh thеy arе all gеnеtiсally rеlatеd. гolyandгy also typiсally oссurs among Ьrothеrs who havе inhеritеd farmland that is too small to bе dividеd into parсеls that сould еaсh sustain a family. Finally, whеre polyandrous marriagеs oссur, altеrnativе sourсеs of inсomе arе not availablе to thе Ьrothеrs; сultivating thе family farm is thе only viaЬlе mеans of subsistеnсе. Undеr thesе есologiсal сonditions, human Ьеhavioral есologists arguе' polyandrous marriagе is aсtually an adaptivе сhoiсе for thе Ь.othЪ.. who еntеr it' rathеr than a maladaptivе Ьy-produсt of еvolvеd dеsirеs еnсountеrlng сonditions for whiсh thеy wеrе not dеsignеd. Undеr thеsе сonditions' thе brothеrs aсhiеvе greatеr rеproduсtivе suссеss Ьy mаintaining joint possеssion of thе farm, working it togеthеr, marrying onе woman, and rеaring thеir joint offspring than thеy would Ьy marrying monogamously. Human Ьеhavioral eсology diffеrs from Еvolutionary Psyсhology in sеvеral kеy rеspесts. First, whеrеas Еvolutionary Psyсhology strives ,o di,.uu.. p,yсhologiсal adaptations to Plеistoсеnееnvironmеnts,human Ьеhaviorai есol' ogy studiеs how human bеhavior is adaptivе to еnvironmеntal сonditions.

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Sесond, Еvolutionary Psyсholоgy Ьеliеvеsthat hцпrаn Ьеhavior is oftеn mal. аdaptivе in есologiсal сonditions that do not геsеmЬlеthosе of our huntergathеrеr anсеstors) Ьut humаn Ьеhavioral есology Ьеliеvеs humans Ьеhavе adaptivеly in a widе rangе оf еnvironmеnts.Third, whilе Еvolutionary Psyсhology triеs to rеvеl.sееnginееrthе еvolvеd natцrе of thе hunran mind from thе vantagе of our Plеistoсеnеpast' human Ьеhavitlralесology appliеs еvolutionary prinсiplеs to oЬsеrvaЬlеhuman bеhavior.Finally, whсrеas Еvolution. ary Psyсhology strivеs to disсovеr a uniform and univеrsаl human naturе' human bеhavioгal есology strivеs to dеterminе how еnvironmеntal differеnсеs Ьеtwееn individuals affесt Ьеhavioral diffеrеnсеs Ьеtwееn thеm. вIвLloGRAPHY Barrеtt'L.' R. DunЬаr, and J. Lyсеtt.2002. Humап ЕuolиtionаrуPsусhologу. Prinсеton'NJ: PrinсеtonUnivеrsityPrеss. Bullеr, D. J. 2005. Adаptiпg Мiпds: ЕuolutioпаrуPsуchologуапd thе Pеrsistепt МIT Pгеss. Quеstior НипtсlltNаturе.СаmЬridgе,N{A: -Гhе Nеu.lSсiепсеof thе Мiпd.3rd еd. Buss' D. |\^.2007. Еuolutioпаrу,Psусhologу: Boston:Allyn and Bасon. Laland, K. N., and c. R. Brown. 2002.Sепsеапd Noпsепsе:Еuolutionаrу Pеrspесtiuеs сlпIIиtпапBеhаuiour.oxford: oxford UnivегsityPrеss. .!Иilson, Е. o. \978. Оп Нumап Nаtиre. СamЬridgе,]vlA:Harvard UnivеrsityPrеss.

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..Еvolution in N1еndеlianPopulations'' (Sеwall Wright) Thе сlassiс papеr ..Еvolution in Меndеliаn Populаtions'' Ьy Amеriсan popul a t i o n g е n е t i с i s tS е w a l l W r i g Ь t w a s p u Ь l i s h е d t n G e п е t i с si n 1 9 3 1 . I n i t , a n d in ..Thе Rolеs of Mutation, InЬrееding,СrossЬrееdingand Sеlесtionin Еvolution,'' a shortеr papеr givеn the following yеaг at an intеrnаtional gеnеtiсs ..аdaptivеlandсongгеss'in whiсh hе introduсеd his famous mеtaphor of an ..shifting Ьalanсе thеory of еvolusсapе'' (sее figurе), \Х/rightprеsеntеdЬis tion.'' His fеllow population gеnеtiсist aсross thе Atlantiс' R. A. Fishеr (1930), hzrd just givеn his nеo-Darwiniаn aссount of еvolutionary сhangе, onе that saw suсh сhangе сoпling аs thе rеsult of trlutatiоnsinto a largе population, and sеlесtiсln thеn еliminating all Ьut thе Ьеst. Wright had workеd for a numЬеr of yеars at thе U.S. Dеpartmеnt of Agriсulturе. From studiеsof thе Ьrееding of сattlе, hе was сorrvinсеd that thе Ьеst way to gеt сhangе is by isolating small gгoups, working within thеm to gеt thе Ьеst of all possiЬlе сharaсtеristiсs, and thеn finally rеintroduсing thе highеst quality to thе wholе hеrd (Provine 1986). .Wright's shiftirrg Ьalanсе thеory followеd thе samе pattеrn: isolation of groups' improvеmеnt within thе group, and thеn mingling with thе wholе. In his сongrеsspaper, !(right rеprеsеntеdthе proсеssas somеthingoссurring on a landsсapе,with thе Ьеst (thе fittеst)Ьеing at thе tops of pеаks аnd thе worst down in thе vallеys. Hе saw еvolution as Ьеing a mаttеr of moving from onе pеak to аnothеr highеr pеаk. Thе сhallеngе was how to gеt down thе sidе of thе first pеak so that onе сould start сlimЬing up thе othеr. Bесаusеsеlесtion

Adaptivе landsсаpеs.Tl thе tops of hills оf adap еvolutionary mеt;rphor< pоssiblеthat Wгiglrtсaг Нaldanе, ..A Маthеmat МеtаstablеPopuIation 28 (19З1),1З7-,|,42'w| fitnеss,drawn Ьy tlrе gе Provinе points out that t information aЬout thе е ultimatеly,thе landsсap

would Ье working agai ..gеnеtiсdrift''' аlso at that rnathеmatiсs shoш may wеll сountеr thе r without (or еvеn dеsp sеlvеs Ье of grеat valuс lutionary сhangе. Тhis is a vеry non-D undеr thе influеnсе of natural sеlесtion. (Do Species, first puЬlishеd tiоns gаvе moге сrеdеn was doing on сhromt 1999.) In part thе infl сomplainеd that natur

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human Ьеhavior is oftеn mal'еsеmЬlеthosе of our hunfеr_ logy bеliеvеshumans Ьеhavе hird, whilе Еvolutionary Psyturе of thе human mind from avioral есology appliеs еvolu'r. Finally, whеrеas Еvolution. and univеrsal human naturе' tе how еnvironmеntal diffеr_ .еrеnсеsЬеtwееnthеm.

ЕuolиtioпаrуPsусhologу. sусhologуапd tbе Persistent [T Prеss. of tbеМind.3rd еd. еш Sсiеltс,e (oпsепsе : Еuolutioпаrу lford UnivеrsityPrеss.

U"'*.YJT.; э'МA:Наrvaro ;'' (SеwаllWright) rulatiorrs''Ьy Amеriсan popuin Geпеtiсsin 1931. In it, and эrееdingand Sеlесtion in Еvoаr at an intегnationag l еnеtiсs rеtaphorof an ..adaptivе land[ting Ьalanсе thеory of еvoluss thе Atlantiс, R. A. Fishеr :ount of еvolutionary сhangе, of mutations into a largе popthе Ьеst. \7right had woгkеd lf Agriсultuге.From studies of rе bеst wаy to gеt сhаngе is Ьy to gеt thе Ьеst of all possiЬlе hе highеst quаlity to thе wholе :hе samе pattеrn: isolation of еn mingling with thе wholе. In jеssas solтеthing oссuггing on ,hеtops of pеaks and thе worst ] a mattеr of moving from onе ls how to gеt down thе sidе of up thе othеr. Bесausе sеlесtion

Аdaptivе landsсapеs.This piсturе, showing how thе fittеr organisms сlimЬ to thеtops of hills of adаptivеfitnеss'illustratеspеrhapsthе most famous еvolutionarymеtаphorof thе twеntiеthсеntuгy(from lfright 1932).It rs possiЬlеthat WrigЬt сamе to tlrе mеtaphorfrоm rеаdingan artiсlеЬy B. S. J. Hаldаnе,..A Мathem:rtiсalThеory сlf Artifiсial and Nаtural Sеlесtion'Pаrt VIII. МеtаstaЬlеPopulations,'' Proсеediпgsof thе Саmbridgе Philosophiсаl Soсiеtу 28 (I9з|' \З7_142, whiсh сontainsa piсtorial reprеsеntation of pеaksof fitnеss,drawn Ьy thе gеnеtiсistС. H. !7addington. Wright,s Ьiographег.!7illiam Provinеpoints out thаt thе landsсapеis сoпdеnsinga hugе amount of infoгmationaЬout tЬe еffесtsof diffеrеntgеnеsаnd that сonsеquеntlv, ultirnatеly, thе landsсаpеmаy not Ье еntirеlусolrеrеnt.SееProvinе l98o.

would Ье working against this' !Иright introduсеd thе сontrovеrsial notion of ..gеnеtiс dri{t,'' also at timеs known as thе ..Sеwall Wright еffесt.'' Hе arguеd that mathеmatiсsshows that, in small groups, thе сhanсе еffесtsof Ьrееding may wеll сountеr thе еffесts of sеlесtion, so nеw fеaturеs сan l.lе produсеd without (or еvеn dеspitе) natllral sеlесtioIr.Tlrеsе nеw fеatuгеs may thеmsеlvеsЬе of grеat valuе, еspесiallyin thе wholе, and сan lеаd to fцrthег еvo. lutionary сhangе. This is a vеry non-Darwiniаn thеory, although latеr vеrsions, partiсularly undеr thе influеnсе of Thеodosius DoЬzhansky' gavе a muсh largеr rolе to natural sеlесtion. (DoЬzhansky's mastеrwork, Gепetics апd tbе Оrigiп of Speсies,first puЬlished irl 19З7, gavе strong еmphasis to \й/right.Latеr еditions gave morе сrеdеnсеto natural sеlесtion,thanks tсl studiеs DoЬzhansky was doing on сlrromosomal variations of fгuit fliеs in nаturе. Sее Rusе 1999.)|n part thе influеnсе on Wright саmе from Неnri Bеrgson, who had сomplainеd that natural sеlесtionсаnnot yiеld innovations. Br.rta f ar greater

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Еuolutioп of Lапguаge influеnсе was FlеrЬеrt Spеnсеr (partiсularly as passеd on Ьy !Иright's tеaсhеr' L. J. Hendеrson). Populations аrе sееn in a kind of balanсе, homogеnеous; when somеtlriпgdisrupts thе balirnсе,сausing frаgmеntationand hеtеrogеnеiry, thе wholе strivеs to rеturn to homogеnеity' аt a highеr lеvеl' This is a сlassiс сasе of Spеnсеriandynamiс еquiliЬrium. In rесеnt yеaгsl thе shifting Ьalаnсе thеory has Ьееn vеry sеvеrеly сritiсizеd, although пrсrstеvolutionistsstill think that thеrе is somе rolе for gеnеtiс drift (sееCoуnе, Barton аnd Tr'rrеlli1'997).At thе molесulаr lеvеl, Ьеnеath thе еffесts of natural sеlесtion, drift is thought to bе vеry importаnt (Kimura 1983) and is thе Ьasis of thе major wаy of сalсulating signifiсantdatеs in еvo..Molесular Еvolu. ..gеnеtiс сloсks''). (Sее thе main еssay lution (through tiorr'' Ьy Franсisсo J. Ayala in this volumе.) B|вLIoGRAPHY Bеrgson'H. 1911.СrеаtiuеЕuollltiсlп.Nеw York:Holt. A сritiquеof Sеwali Сoynе,J. A., N. H. Barton'and М. Turеlli.1997.Pеrspесtivе: .Wright's shiftingЬаlanсеthеoryof еvolution.Еuolutklп51' no. 3: 64З-671. Г)oЬzhansky, T. [|9з7] 1951,Gепetiсsапd thе Оrigiп of Spесiеs'Зrd еd. Nеw York: СolumЬiaUnivеrsityPrеss. Fishег'R. A. 1930' Тhe GепеticаIThеorу of Nаturаl Sеlесtion.oхford: Oхford UnivеrsityPгеss. Hеndеrson,L' J. 1917.Thе Оrdеr сlfNаtиre.СаmЬridgе,MA: HarvardUnivеrsity Prеss. ,Гbе -ГЬеrlr1' Nеutrаl of Мoleсulаr Еuсllutioп.СamЬridgе: Kimura, М. 1983. СamЬridgеUnivеrsityPтеss. Provinе,!и. B. 1986.SаuаIIWrightttltdЕurllutiсlпаrl,Birllogу.Сhiсago:Univеrsity сlf Сhiсago Prеss. Rusе, М. 1996.Мonаd to Мап: Tbе Сoпсeptof Progrеssiп ЕuolutiсlпаrуBiologу. CamЬridgе,MA: Harvard UnivеrsityPrеss. 1999.Муsterу of Муstеriеs:Is Еuolиtionа SсlсiаIСoпstruсtiсlп?СаmЬridgе' МA: Harvагd UrrivеrsityPrеss. Sреnсеr,L7.1862, FirstPriпсiplеs.London:Williаmsand Nоrgatе. populatiоns'Gеnеtiсs16:97-159. Wright,s. 193l. Еvolutionin \,lеndе|ian 19З2.T|.lеrolеsof mutation,inЬrееding, сrossЬтееding and sеlесtionin еvolution.Proсееdiпgsof thе Siхth lпtеrпаtioпаlСoпgressrlf Gепеtiсs1: -М.R. . 356-366.

Еvolution of languagе Although many animals сommuniсatе using voсalizations' only humans usе сomplех languagе, Ьasеd on a disсrеtе numЬеr of arЬitrary Ьits of Sounds and gеsturеs' to сomprеhеnd and produсе a sееmingly infinitе numЬеr of novеl mеssagеs.Listеrringto spеесh аnd rеading аrе sеnsory aspесts of lаnguagе' whilе talking, writing, and Ьody languagе arе motor aspесts.In thе |960s, Сhаrlеs Hoсkеtt listеd 15 univеrsal dеsign fеaturеs that distinguish human languagе from сommuniсation systеms in othеr animals. Нoсkеtt viеwеd thrее fеattrrеsas partiсularly importаnt for lruman languagе:(1) displzrсеmеnt,or bеing aЬlе to сommшIriсatеabout mattеrs that arе rеmotе in tirnе and spасе; (2) produсtivity, whiсh is tlrе ability to сommuniсatе an

opеn-еndеd variеty oi r Ь е r o f m е a n i n g , l е spsh o nitе sеt of mеaningful г е f l е x i v е n е s s i,n w h i с | gua8е'аnd prеvariсeti sagеs. Although langu Kanzi, show subtlе sig t h е i r s i g n е do г с o n l P u t muniсations rеmain ех By thе timе а humal.rс} on hеr parеnts and ask y е a r - o l dс h i m p a n z е е с, muniсаrionon thе orсr tl.rеirlanguagе skills to produсing thе full rang hominins еvolvе lаnguс from thе anсеstorsof tl Sсhсllirrshavе Ьееrrt win's timе. Nonеthеlеs m o u s l y Ь a n n е d a I Iс t - ' r languagе Ьесausеof its namеs that havе bееn g еsis, for еxamplе, sl-t ..moo, sounds suсh as attгiЬutеs thе еnrегg,е atеd with physiсal l;rЬo originatеd from еmotiо h y p o t h е s е sd o n o t l е n d Notions аЬout whе today as thеy wеrе a с millions of yеars old; с Among thе lattеr. soг ..сultu arisеn bеforе thе was сhаraсtеrizеdЬy са als, pеrsonal :rdoгпmе Uppеr Palеolithiс tooln to stonе' and thеir too morе spесiаlizеd for pа agrее that Uppеr Palеo 40,000 yеars ago' thеy o l o g i s t s Ь е l i е v еt h l r t t h sumption of linguistiс .W Ьееn plaсеd on thе stеаd, that numеrol1s points, еvidеnсе of tr o с с u r r е dm u с h е а r l i с r '

Еuolutioп of Lапguаgе passеdon Ьy \Х/right'stеaсhеr, .ind of Ьalanсе, homogеnеous; fragmеntation and hеtеrogеnеity, at a highеr lеvеl' This is a 1.

y has Ьееn vеry sеvеrеly сriti. h а t t h е r еi s s o m е r o l е f o г g е n е At thе molесular lеvеl, Ьеnеath t to Ье vеry important (Kimurа t аtеsin еvou l a r i n gs i g n i f i с a n d ..Мolесular Еvoluтain еssay

Holt. A сritiquе оf Sеwаll Pеrspесtivе: Е u o l u t i o п5 1 ' n o . 3 : 6 4 З _ 6 7 \ . ,igiп of Spеciеs. 3rd еd. Nеw York: rаl Sеlectioп' Oxford: oxford r b r i . l g еМ. A : Н e r r . n r dI I n i v е г s i t y ' аr Еu,,Iиtiсlп,C.lrrlhridgе: Univеrsiгy аrу Bi,,logу.Chiсаg<-l: 'rogrеssiп Еuсllцtioпаrу Biologу. а Soсiаl Сoпstruсtion! CarrrЬridgе, ms аnd Norgarе. э n s .G е п е l i с s | ы 9 7 _ | 5 9 . : r o s s Ь r е е d i nаgn d s е I е с t i o ni n паl Сoпgrеssof Geпеtiсs'-,.*.

voсalizations,only humanS usе Ьеr of arbitrzrryЬits of soцnds a sееmingly irrfinitс nцmЬеr of ling arе sеnsory aspесts of lan]uagеarе motor aspесts. In thе dеsign fеaturеs that distinguish эms in othеr animals. Hoсkеtt nt for human languаgе: (1) dis) o u t m а t t е г st h a t a г е г е m o t е i n t h е а Ь i I i t vt o с o m m u n i с a t е а n

opеn-еndеdvariеty of novеl mеssagеs;and (3) duality, in whiсh a small numЬеrof meaninglеssphonologiсal еlеmеntsmay Ье сomЬinеd to сrеatе an infinitе sеt of mеaningful uttеranсеs.Two othеr intегеstingdеsign fеaturеs arе геflехivеnеss,in whiсh onе сan usе languagе to сoпlmuniсate aЬout lаnguagе,and prеvariсation,whегеЬy languagесan Ье цsеd to dеlivеr fЪlsеmеs. sagеs.Although languаgе_trainеdapеs suсh as thе wеll.known ЬonoЬo, Kanzi, show suЬtlе signs of utilizing somе of Hoсkеtt's dеsign fеаturеs in thеir signеd or сOmputеr-faсilitatеd сommuniсаtions with pеoplе, thеir сommuniсаtions rеmain еxtгеmеly simplе dеspitе dесadеs of intеnsе sсhooling. By thе timе a human сhild is four years old, shе is likеly to fastеn a Ьеady еyе on hеr paгеnts аnd ask, ..\й/hеrеdid I сomе fronr?'' Thе highly trainеd fouryеar-oldсhimpanzее,on thе othеr hаnd, is likеly to sign a spontanеousсomnruпiсаtionon thе ordеr of ..сookiе,сookiе, hurry.'' Apеs, in fасt, nеvсr usе thеirlanguagеskills to ask quеstions.Furrhеr, thеir larynxеs arе inсapаЬlе of produсingthе full rangе of human spеесhsounds. How and whеn, thеn, did hominins еvolvе languagе during thе 5 to 7 пrillion yеars sinсе thеy divеrgеd from thе anсеstorsof thеir сlosеstgеnеtiссousins, thе сhimpanzееs? Sсholars havе Ьееn fasсinatеd by this quеstion sinсе аt lеast Сharlеs Darwin's timе. Nonеthеlеss,in 1866 thе influеntial Linguistiс Soсiеty of Paris famously Ьannеd all сonrmuniсationsdеaling witlr tlrе origin and еvolution of languagеЬесausеof its spесulativеnaturе, whiсli is геvеalеdin thе amusing namеsthat havе Ьееr-r givеn to various hypothеsеs.Thе ..Ьow-wow'' hypоthеsis, for ехamplе, suggеStsthat languagе Ьеgan as imitations of natural sounds suсh as ..rnoo''' ,,Ьozz,'' аnd ..сrash'';thе ..yo-hеavе-ho''hypothеsis attriЬutеs thе еmеrgеnсе of languagе to rhythmiс сhants аnd gгunts assoсiatеdwith physiсal laЬor; and thе ..pooh-pooh'' hypothеsis suggеstslanguagе originatеdfrom еmotional сriеs or ехсlamations. Although intеrеsting,thеsе hypothеsеsdo not lеnd tЬеmsеlvеsto sсiеntifiсtеsting. Notions aЬout whеn аnd lrow languagе first arosе аrе as сontrovеrsial todаy as thеy wеrе il сеntury ago. Sonlе rеsеаrсhеrsthink thаt larrguagеis millions of yеars old; othеrs Ьеliеvе it originatеd a mеrе 40,000 yеars ago. Among thе lattеr, s
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еvеrrtuallyinvаdеd lang t а r g е to Г n a t u r а l 5 е l е с t е x p l i с i t l y r е j е с гг h е n o t i с сall systеrns,аlthor-rglrt . . t o p - d t l w n ' 's с h о o l o f t mans еvolvеd thе aЬilit1 infinitе numЬеr oi rulеnuity hy;lothеsis,''on th of inсrеmеntal еvolutior and sееs its roots rеflесt wild primatеs havе in t

man) еxtеnd thе disсuss сalls Ьеtwееn rnothеr аt Nсl disсussion of lan1 ing thе wеll-known gеs

on thе dееp psyсholtlg guagе' inсiudir-rgmothе tilе, and gеsturаl сomp wе also usе flailing han physiсаl сontасt rr,ithp matеs also сtlmЬirrеsu siorrLrllyolfaсtoгy signa diffеrеnсеis that, in ad primiltе produсеs voсa abovе. Aсlvoсаtеsсlf gе е v е r l t u a l l yt о l а I l g . u а gi 6nеd narrowly (е.g.,mz thаt рroduсе visuzrl,асс M 1 ' o w n i d е а s. r r еi n Ьеliеvеthat thе гoots o{ rеsеnts a kind оf signс еmеrgеnсе of thе first 1 сhimpаrrzееmothеrs us lnothеrs dеlivеr e сons ..mothеrеsе,''or tnusiс fеatttrеshеlp ЬaЬiеsаrс guаgеs.Сhimpanzее m tЬеir infants, who rеm unaidеd' to thеir hairy еvoltltion of walking u thеy do rеtain a grasp t h е i г h е l p l е s si n f l l l l t ' i l

Unс]еrthеsе сirсumsta adaptivе for геassurin movеd from thеir rnot

а kirrd сlf disеmЬodrе

Еuolutiсlп of Lапguаgе tan sееing languagе as having r Ьеiiеvеit еvolvеd more graduoriginatеdstill еarliеr. Skеlеtal гs of thе skull and nесk that falаt had еvсllvеdto thеir modеrn е rapid voсalizationsthat сharеdgеthat spеесhnееd not еntail and that rudimеntary languagе l o f t h е Ь r a i n , Ь е l i е v еt h a t l a n эrе 2 milliоn yеars ago. Thеy coсasts)that rеproduсе dеtails 'al сortех) that wеrе imprintеd ; ( o r o t h е r a n i m a l s )w е r е a l i v е . lсity (аs a surrogatе for Ьгain hominin еvolution. Although ts of thе Ьrain, Broсa's spеесh spесiallyimportant for сoordilе' mouth' and larynх that arе rtеd with а spесifiс pattеrn of Ь r а i l l s o Г o u r с | o s е s tg е n е г i с in is somеtimеsrеproduсеd оn n f o s s i l h o m i n i n s s u g g е s tt h а t е b е g u nd е v е l o p i n gЬ y 1 . 9 m i l hе samе timе аlso suggеst that right-handеd,whiсh apеs as a owеvеr'thаt brains had not yеt еs, and thаt thе еvidеnсе from to intеrprеt.Thе suggеstion of imе should thеrеforе Ье viеwеd lnеssЬoth dеpеnd hеavily on thе - ,Ь r a i n sr h a tа r е а l s o а s y m m е г r i o not Ьеginto approaсh human to languagе funсtions, thе lеft lvеd in skillеd movеmеnts, suсh , timе-sеquеnсingproсеssеs.Thе moгеglobal pursuits' suсh as vi. faсеs, apprесiating humor, and thе lеft hаnd. Although it is thе siсal right hеmisphеrе that proJ 1 5o L l rU t t е r a n с е sl n. t h i s s е n s е , ft hеmisphеrе. dy had nothing to do with thе d as a kind of аuditоry frill that

еvеntually invadеd lаnguagе.Thеy also assеrt that musiсal skills wеrе not a targеt of naturаl sеlесtionin thе sаme way that linguistiс aЬilitiеs wеге, and ехpliсitly rеjесtthе notion that languagесould havе еvolvеd from primatеlikе сall systеms' although thеy aсknowlеdgе that tonе of voiсе likеly did. This ..top-down'' sсhool of thought thеrеforе foсusеs on undеrstаnding how hu. mans еvolvеd thе aЬility to link symЬoliс rеfеrеntialsounds into a potеntially infinitе numЬеr of rulе-govеrnеdmеaningful sеntеnсеs.An opposing ..сontinuity hypothеsis,''on thе othеr hand, posits that languagееmеrgеdаs a rеsult of inсrеmеntalеvolution from thе primatе сall systеmsof our eаrly anсestors and sееsits roots rеflесtеdin thе сomЬinations of prosodiс сalls that various wild primatеs havе in thеir rеpеrtoirеs.Somе сontinr-ritists(е.g.,John Nеwmаn) ехtеnd thе disсussion еvеn furthеr into thе past Ьy foсusing on сontaсt сalls bеtwееn mothеr аnd infant mammals. No disсussion оf languagееvolution would Ье соmplеtе without mеntion. ing thе wеll-known gеstural.originshypothеsis,whiсh rесognizеsand Ьuilds on thе dееp psyсholсlgiсallinks Ьеtwееn thought, spеесh,and gеsturе.Languagе' inсluding mothеr-infant intеraсtions' еnсompassеsvoсal, visual, taсtilе, and gеstuгal сomponеnts. Humans do not just ..talk'' with our voiсеs; wе also usе flailing hands, faсial ехprеssions,Ьody posturе' and (somеtimеs) physiсal сontaсt with pеoplе or oЬjесts to сonvеy mеaning. Nonhuman primatеs also сomЬinе suсh gеsturеswith еmotional voсalizаtions, and oссa. sionally оlfaсtory signals, in thеir blеnd of multinrodal сommuniсation. Thе diffеrеnсе is that, in addition tо еmotionаl сalls and inttlnations, thе human primatе produсеs voсаlizаtions that havе thе linguistiс propеrtiеs outlinеd aЬovе. Advoсatеs of gеstural origins think that thе natural sеlесtion that lеd еvеntuallyto languagеinitially targеtеdgеsturalсommuniсations, Ье thеy dеfinеd naгrowly (..g., manual gеsturеs)or morе Ьroadly (аrtiсulatory gеsturеs that produсе visual, aсoustiс,voсal, or taсtilе signals). My own idеas arе in kееping with thе gеstural hypothеsis,writ Ьroadly. I Ьеliеvеthаt thе roсltsof languagеarе ехtгеmеlyanсiеnt and that prosody rеprеsеnts а kind of signaturе that is lеft ovеr from еvеnts that prесеdеd thе еmеrgеnсеof thе first languagе.Although thе Ьody languаgеthat human and сhimpаnzее mothеrs usе with thеir infants is virtually idеntiсal, only human mothеrs dеlivеr a сonstant strеam of ЬaЬy talk, whiсh is vеry prosodiс. Suсh ..mothеrеsе'''сrrпrusiсal spеесh,is univеrsal among humans, and its eсoustiс fеаturеshеlp ЬaЬiеs аround thе world lеarn thе struсturеsof thеir nativе languagеs.Сhimpanzее mothеrs dirесt fеw, if any, spесial voсalizations toward thеir infants, who rеmain physiсally attасhеd to thеir mothеrs Ьy сlinging' unaidеd, to thеir hairy сhеsts.Bесausеof dеvеlopmеntalеffесtsrеlatеd to thе еvolution оf walking upright, human infants havе lost this aЬility, although thеy do rеtain a grasping rеflех. Еarly hominin mothеrs must havе сarriеd thеir hеlplеss infants in thеir arms' at lеast until ЬaЬy slings wеrе invеntеd. Undеr thеsесirсumstanсеs'soothing nratеrnalvoсalizations would havе Ьееn adaptivе for rеassuringnеarЬy infants thаt wеrе, of nесеssity,pеriodiсally rеmovеd from thеir mothеrs' еmЬraсеs.Tonе of voiсе may thus havе еvolvеd as a kind of disеmЬоdiеd ехtеnsion of mothеrs' сradling arms. Taking a сuе

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Еuolutioп of Lапgиаgе from how modеrn infants Ьеgin to aсquirе languagе' it is rеasonaЬlе to surmisе that natural sеleсtion sсulptеd inсrеmеntal сhangеs in mothеr-infant prosodiс' taсtilе' visual, and gеstural intеraсtions,whiсh faсilitatеdthе еmеrgеnсе of linguistiс fеaturеs and, еvеntually (pеrhaps far down thе linе)' thе first languagе. Nееdlеss to say' likе thе othеr idеas aЬout languagе origins, this ..putting thе ЬaЬy down'' hypothеsis is сontrovеrsial. Bесausе of thе widе disparity in сurrеnt соnjесturеs rеgarding thе еvolution of languagе,оnе might Ье tеmptеd to сonсludе that rеsеarсhon this suЬjесt has not improvеd mцсh sinсе thе days of thе Ьow-wow, yo-hеavе-ho, and pooh-pooh hypothеsеs.This is not truе' howеvеr. Advanсеs in mеdiсal imaging tесhnolоgy and thе nеurosсiеnсеs arе сurrеntly pеrmitting еluсidation of thе nеurologiсal suЬstratеsof languagе (е.8.,thе rolе of mirror nеurons);thе innatе naturе of languagе is Ьесoming сlеarеr from fasсinating rеsеarсh on dеaf individuals; and gеnеs that havе a rolе in thе dеvеlopmеnt of normal spokеn languagе (е.g.,FoХP2) arе bеginning to Ье idеntifiеd. Languagе is what sеts us apart frоm thе othеr primatеs, and today wе havе morе sophistiсatеd idеas aЬout how it еvolvеd than wе did a hundrеd yеars ago. Bесause of thе information еxplosion that is сurrеntly undеr way. wе should soon know morе. в|BLIoGRAPнY Armstrong,D. F.' !и. С. Stоkoе,аnd S. Е. Wilсox. 1995. Gеstureапd the Nаture of Lапguаge.СamЬridgе:СamЬridgеUnivеrsityPrеss. Falk, D. 2ОО4a,Brаindапсe:Nеt'uDiscrluеriеsаbout Humап Оrigiпs апd Brаiп Еuolutioп,Rеvisеdаnd ехpandеdеd. Gainеsvillе:UnivеrsityPrеssof Florida. 2004ь. Prеiinguistiсеvolutionin еarly hominins:Whеnсеmothеrеsе? Bеhаuiorаlапd Brаiп Sсiепсеs 27:491-541. 2О09.Fiпdiпg Оur Tongues:Мothers,Iпfаntsаnd the Оrigiпs of Lаnguаgе. Nеw York: Basiс Books. Hoсkеtt,С, 1966.Thе prоЬlеmоf univеrsals in languаgе. In J. GrееnЬеrg, еd., Uniuersаlsсlf Lапguаge,1-29. СamЬridgе,MA: MIT Рrеss. Holdеn, С. 1998.No lastword on languagеorigins'Sсiепсе282: t455-I458. -Гhе 'Word: Kеnnеally,С. 2ОО7. First Thе Seаrchfor thе origiпs of Lапguаgе.Nеw Y o r k :V i k i n g . Laitman,J. T.' J. S. RеidеnЬеrg, and Р. J. Gannon.1992.Fossilskullsand hominid voсal traсts:Nеw approaсhеsto сhartingthе еvolutionof human spеесh.In J. !Иind еt al', еds.,I,аnguаgеОrigiп: А МultidisсipliпаrуАpprсlасh,395_407' Dordrесht,Thе Nеthеrlands: Kluwеr АсadеmiсPuЬlishеrs. Мasataka,N. 2003. Тhe onset of Lаnguаge.СamЬridgе:СamЬridgеUnivеrsity Prеss. l\4сBrеarty'S., and A. S. Brooks 2000. Thе rеvolutionthаt wasn't:A nеw intеrprеtationof thе origin of modеrnhuman Ьеhavior.Jourпаl of Нumап Е u o l u t i o п3 9 : 4 5 3 _ 5 6 3 . Nеwman,J. D. 2004. МothеrеsеЬy any othеrnamе:Мothеr-infantсommuniсation in non-homininmammals.Behаuiorаlаnd Brаin Sсiепcеs27: 51'9_520. .William Pinkеr' S. 1994. Тbе Lапgиаgеlпstinсt.Nеw York: Мorrow and Сompany. Savagе-RumЬaugh, S.' S. G. Shankеr,аnd T. J. Taylor.2ОО\.Apes,Lаnguаge,апd the Humап Мiиl. Nеw York: oxford Univеrsity Prеss

Еvolution of lifе h

W h y d o s o m е p l a n t s '' yеars aftеr gеrminatinр as thе аnnuals in your d o s o m е а n i m a l s ,s u с h сompаrativеly fеw tЬ dwеlling krill' prоduсе .W.hat arе thе сonsеquе tion of thеsе organism rеalm of lifе-history еv A n o r g а n i s m ' sl i f е h t h е k е y s t a g е sа n d t r а r г е p г o d u с t i o n .L i f е - h i s p г o d U с t i o n la g е a n d s i ; spring;and thе аgе tll oftеn vary suЬstаntiа triguing ways. Thе goa in thе pattеrns of gror 8 е n е r a t ег h i s v a r i а t i о n this variation. Thе stud quirеs intеgrating сon< with an undеrstanding A с t u a r i a l s t u d i е sЬ 1 а n а l y s i si n h u m e n s .l n t е г n so f h u m а n m o r t e r i s k o f d е a t h .Е с o I o g i с d е a t h r a t е s ,f r t l m w h i с suсh as thе nеt rеpгod futurе ехpесtеd rеpгo сharaсtеristiсs suсh as variaЬlеs arе dirесtly rt n е г r е p г o d u с t i v еr а t е )r individuals that produr thе dirесt Iink Ьеtwе shapеs thе divегsity of а Ь | е sа r е а l s o с е n t r a il ropiс of importаnсе r spесiеs. М o d е r n l i f е - h i s t o r yl o n t с o l е i n t h е 1 9 5 0 s .] nithologist who infusе H i s m o s t i n f l u е n t i a еl a т thаt Ьirds lаy in a nеst maximizеs thе torаl o known as thе ..Laсk Сl

Еuolutiolt of Lifе Histсlriеs пagе'it is rеasonaЬlе to surll сhangеs in mothег.infant ;, whiсh faсilitatеd thе еmеrhaps far down thе linе), thе lеas aЬout languagе origins, rovеrsial. есturеs геgarding thе еvolurdе that rеsearсh on this suЬbow-wow, yo-hеavе-ho, and г . A d v а n с е si n m е d i с a l i m a g rtly pеrmitting еluсidation of : rolе of mirror nеurons): thе :rom fasсinating rеsеarсh on thе dеvеlopmеnt of normal г o Ь е r d е n г i f i е dL. a n g u a g е i s todаy rvе havе morе sophisr hundrеdyеars ago. Bесausе undеr way. wе should soon

)95. Gеstнreапd tЬе Nаture of еss. Humаttorigiпs аnd Brаin е:UnivеrsityPrеssof Floridа. -rins:.Whеnсеmothеrеsе? ts апd thе origiпs of Lапguаgе. еd., uagе.In J. GrееnЬеrg, : МIT Prеss. Sciепсе2-82z1'455_|458. thе Origiпs of Lапguаge.New hominid 992.FossiIskullsar"rd olutionof humаnspеесh.In isсipliпаrуApproасh, з9 5_407. Publishеrs. Univеrsity гidgе:C:rmbridgс ln thatwasn,t:A nеw еhavior..|oиrпаlof l7umап : М o t h е r - i n f а nс tс l m m u n i с a t i o n п Sсiепcеs 27: 51'9-52О. WilliamМorrow and Compаny. or.2001.Apеs' Lаltguаge,аnd -D.F. y Prеss.

Еvоlution of lifе historiеs Why do somе plants, suсh as rеdwood trееs' Ьеgin to rеproduсе only nrany yеars aftеr gеrminating аnd livе for hundrеds of yеars, whеrеas othеrs' suсh aS thе annuals in your gardеn' mаturе youllg аnd livе only onе sеason?.Why do somе ar-rimais,suсh as humans, produсе onе offspring at a timе and rеar соmparativеly fеw throughout lifе, whеrеas othеrs, suсh as thе oсеandlvеlling krill, produсе thousands of young, most of whiсh сannot survivе? Whаt are tЬе сonsеqrrепсеsof thеsеdiffеrеnсеsfor thе есology and thе еvolutiоn of thеsе organisn-rs? Thеsе, and a variеty of rеlatеd quеstions' arе in thе rеalm of lifе-history еvolution. An organisrn'slifе history is its pattеrn of survival and rеproduсtion' plus thе kеy stagеsand transitions in thе lifе сyсlе that influеnсе its survivаl and rеproduсtion. Lifе-history traits inсludе growth and dеvеlopmеnt Ьеforе rеproduсtion;agе and sizе аt sехual maturitу; thе numЬеr, sizе, and seх of offspring;and thе agе of dеath. Spесiеs,zlnd еvеn p<rpulationswithin spесiеs, oftеn vary suЬstantially in lifе-history сhаraсtеristiсsin prеdiсtaЬlе and in. triguing ways. Thе goal of lifе-history studiеs is to undеrstand this variation in thе pattеrns of growth and rеproduсtion, thе есologiсal сonditions that gеnеratеtlris variation, and thе есоlogiсаl and еvolutionary сonsеquеnсеsof this variation. Thе study of lifе historiеs, whеthеr еmpiriсal or thеorеtiсal, rеquirеs intеgrating сonсеpts of gеnеtiсs аnd dеvеlopmеnt with есology and with an urrdеrstandingoГ гhе organism's litЪ сyсlе. Aсtuarial studiеs Ьy insuranсе сompaniеs arе an еxamplе of lifе-history аnalysis in humans. Itrsuranсеaсtuariеs usе lifе taЬlеs to dеsсriЬе thе pattеrns of human mсlrtirlit1,at spесifiс a8еs to аssеss lrow agе influеnсеs thе risk of dеath. Есologiсal lifе tаЬlе analysis is Ьasеd on agе-spесifiсЬirth аnd dеathratеs, from whiсh sсiеntistsсan сalсulatе a vaгiеty of usеful variaЬlеs suсlras thе nеt rеproduсtivе ratе (thе total numЬеr of offspring produсеd), futurе ехpесtеd rеproduсtiorr (сallеd rеproduсtivе valuе), аnd еmеrgеnt сharaсtеristiсssuсh as thе rеlationship of rеproduсtion to mortality. Thеsе variablеsаrе dirесtly rеlatеd to Iitnеss,a fur-rсtionof total rеproduсtion (thе nеt rеproduсtivе rаtе) аnd thе sсhеdu]еof геprodr.rсtion; fitnеss is higirеr foг individuals that produсе rеlativеly morе offspring morе quiсkly. Bесausе of thе dirесt link Ьеtwееn lifе-history traits and fitnеss, natural sеlесtion shapеsthе divеrsity of lifе-histсlrYstratеgiesobsеrvеd in naturе. Thеsе variаЬlеs arе аlso сеntгаrlto how есologists prеdiсt population fluсtuations, a topiс of importanсе to thе managеmеnt of harvеstеd or protесtеd wild spесiеs. Мodеrn lifе-history аnalysis traсеs to Dаvid Laсk in thе 1940s and Lаmont Сolе in thе 1950s. David Laсk (1947) was a population Ьiologist and ornithologistwho infusеd Darwinian thinking into thе study of lifе histories. Нis most influеntiаlеarly lifе.history hypoгhеsiswas tlrаt thе numЬеr of еggs that Ьirds l:ly in a nеsting attеnlpt (thеir ..сlutсh sizе'') should Ье that whiсh maximizеs thе total offspring flеdgеd from that сlutсh. This has Ьесomе known as thе ..Laсk Сlrrtсh Sizе.''To mаximizе thе pгoduсtion of flеdglings,

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Еuolutioп of Life Нistoriеs parеnts must Ьalanсе thе numЬеr оf hatсhlingswith thеir aЬility to rеar thеm to indеpеndеnсе. If parеnts attеmpt to геar morе offspring than thеy сan support' somе or all of thе young may diе. Likеwisе, pаrеnts prоduсing fеwеr offspring than thеy сan rеar will flеdgе fеwеr than thеy сould, and will likе. wisе havе lowеr rеproduсtivе suссеss than if thеy had produсеd a largеr сlutсh. Ехpеrimеntal studiеs on many spесiеsof Ьirds, in whiсh сlutсhеs arе аrtifiсially еnlargеd,havе found that сlutсh sizеs produсеd Ьy Ьirds arе gеnеrally smallеr than thе Laсk Сlutсh Sizе (е.g.,Vandеr.Wеrf 1992). This disсrеpanсy Ьеtwееn thе Laсk and thе oЬsеrvеd сlutсh sizеs stimulаted a grеat divеrsity of еxpеrimеntal and thеorеtiсal study that in turn gеnеratеd many adaptivе hypothеsеs' mainly dеrivеd from optimization analysеs (е.g.,..optimаlity modеls',; Orzaсk and SoЬеr 1994) that Ьесamе сommonplaсе Ьy thе 1970s and 1980s. For ехamplе, modеls prеdiсt and еxpеrimеntal studiеs hаvе shown that сurrеnt yеar rеproduсtivе еffort аffесts futurе rеproduсtivе suссеss of parеnts; that is, thеrе is a tradе-off Ьеtwееn сurrеnt and futurе rеproduсtivе еffort (sее rеviеws in Godfray et a|. 1991 and Rсlff 1992\. \й/hеn this and othеr tradе-offs (suсh as that bеtwееn сlutсh sizе and еgg sizе; Smith and Frеtwеll 1'974) are inсorporatеd into modеls of сlutсh sizе, wе саn ехplain muсh of thе оЬsеrvеd dеviation Ьеtwееn rеаl сlutсh sizеs and Laсk's prе. diсtеd сlutсh sizеs. Following on Laсk's introduсtiоn of Darwinian thlnking into thе study of lifе-historyvariation, Lamont Сolе (1954) introduсеd a mathеmatiсalframе. work to thе study of lifе.history есology Ьy dеmonstrating hсlw сhangеs in dеmographiс variaЬlеs influеnсе thе ratе of inсrеasе of a population (Roff 7992). Мost famously, hе raisеd a simplе mathеmatiсal сonundrum known as Сolе's paradoх: an оrgаnism that livеs forеvеr, produсing и offspring pеr yеar, lеavеs no morе dеsсеndants' all еlsе Ьеing equal, than onе that livеs for just onе yеar (an annual organism),Ьut produсеsz + 1 offspring.Thе rеason is thаt оnly onе offspring is rеquirеd to rеplaсе thе parеnt in our annual organ. ism, aftеr whiсh Ьoth thе immortal and аnnuаl organism produсе thе samе numЬеr of offspring. Givеn thе impossiЬility of irnmсlrtаlity, why do not all organisms еvolvе toward thе shortеst, simplеst lifе history? Мany Ьiologists, .Williams, inсluding Williаm D. Hamilton, Gеorgе and Еriс Сharnov (Сharnov and Sсhаffеr |97З), havе taсklеd this сonundrum, and its solution wаs sеminal to thе formalization of Darwinian thinking in modеrn есolоgy. Thе solution to Сolе's paradoх rеquirеs rесognition that еaсh lifе-history dесision сausеs a shift in thе proЬаЬility оf aссruing сеrtain Ьеnеfits,and сеrtain сosts, in tеrms of survival and rеprоduсtion.For еxamplе' if rеproduсtivеsuссеss inсrеasеs with agе (е.g., duе to Ьеnеfits of parеntal ехpеriеnсе) and thе risk of moгtality Ьеtwееn rеproduсtivе pеriods is low, thеn sеlесtion may favor rеproduсtion for multiplе sеasons. In с
funсtion сannot Ье . offs, and how Ьеhav сyсlе influеnсе survil thе сеntral quеstion i spесtivеs of Laсk anl lifе historiеs that hаs aсtivе today. Modern lifе-histor thе еnvironmеnt' dе strain lifе-history val сan еvolvе rapidly w duсtion of prеdator onto nеw host spес 2007). Selесtivе prеd has lеd to thе еvoluti tеns of gеnеrations(I tion favors rеprсlduс sharеd еvolutionary l isms, gеnеtiс variаtio еvolution of lifе-hist tionary biologists to ation, dеvеlopmеnta so that сausе-and-еf Thе Darwinian pеr and othеr fiеlds of Ь сеnсе and lifе span in fluеnсеd Ьy an organi rеproduсtion. In mos сlinеs with agе. Thur lеss than doеs morta arе undеr wеakеr sеlе this dесlinе in thе int Sеnеsсеnсе.Сouplеd traits that fаvor suссе сost to ultimatе long gеnеs havе Ьееn idеn only on thе old сan еr mulation of dеlеtеrio N4orе powеrful mat morе insightful ехpеri lifе.history variation l in genеrating nеW spe latеd into thе appliеd еvolution influеnсеs tl tainability of agriсult and disеasеrеlatеsto

Еuolutiolt of Life Histories with thеir aЬility to rе2rгthеm 'е offspringthan thеy сan sup. visе'parеnts pr
funсtion сannot Ье аlloсatеd to othеr funсtions. Undеrstanding thеsе tradеoffs, аnd how Ьеhavioral or dеvеlopmеntal dесisions at onе stagе of thе lifе сyсlеinfluеnсеsurvival and rеproduсtion at othеr stagеs(and totаl fitnеss),is thе сеntral quеstion in thе study of lifе-history еvolution. Thе Darwinian pеrspесtivеsof Lасk аnd Сolе Ьгouglrt а nеw lvav of thinking into thе study of lifе historiеs that has lеd to myriad insights and a fiеld of inquiry that rs vеry aсtivеtoday. Мodеrn lifе-history analysеsaim to undеrstand how еvolutionary history, thе еnvironmеnt, dеvеlopmеnt, and inhеritanсе intеraсt to сrеatе and сonstrain lifе-history v:rriatior:r.An irnportant rесеnt insight is that lifе histoгiеs сan еvolvе rapidly whеn еnvironmеnts сhangе (е.g.,thе еxpеrimеntal introduсtion of prеdаtoгs, сoпlmеrсizll еxploitation Ьy humans, and ехpansion onto nеw hоst spесiеs Ьy parasitеs of plants and animals) (Сarroll еt al. 2007). Sеlесtivе prеdatior-ror lrarvеsting of lаrgе individuals, as in fishеriеs, has lеd to thе еvolution of suЬstantially rеduсеd agе and size at maturity ovеr tеnsof gеnеrirtions(Hutсhings аnd Frasеr 2008); this lrарpеns Ьесаusеsеlесtion favors rеproduсtion Ьеforе animals arе еatеn оr harvеstеd. Thus, whilе sharеdеvolutionary lristor},tеndsto сrеatе similаritiеs among rеlаtеd organisms, gеnеtiс variation for lifе-history trаits is aЬundant and allows thе rapid еvoiution of lifе-history stratеgiеs'Suсh ongoing аdаptation allows еvolutionary Ьiologists to wеigh thе rеlative influеnсеsof phylogеny' gеnеtiс vari. ation, dеvеlopmеntal systеms, and thе еnvironmеnt ir-rshaping lifе historiеs, so that саusе-аnd-еffесtrеlationslripsЬесomе сlеarеr. Thе Darwinian perspесtivеon lifе historiеs сan Ьring insights to mеdiсinе and othеr fiеlds of Ьiology, inсluding publiс hеalth сonсеrns suсh as sеnеsсеnсеand lifе span in aging human soсiеtiеs.Thе еvolution of lifе span is inf]uеnсеdЬv arr oгganism'srеproduсtivеvaluе, thе mеasurе of futurе ехpесtеd rеproduсtion. In most organisms onсе Ьrееding starts rеproduсtivе valuе dесlinеs with agе. Thus mоrtality latе in lifе affесts total rеproduсtion muсh lеss than doеs mortality еarly in lifе, so tгaits аffесting mortаlity latе in lifе arе undеr wеаkеr sеlесtionthan arе traits affесtingmortality еarly in lifе. It is this dесlinе irr the irrtеnsityof sеlесtionwith agе that аllows thе еvolution of sеnеsсеnсе. Сouplеd with thе sеlесtivеаdvantagе of short gеnеration timеs' trаitsthat fаvoг suссеssfulrеproduсtion еariy in iifе will Ье fЪvorеdеvеn at a сost to ultimate longеvity (an ехamplе of antagonistiс plеiotropy); indееd, gеnеshavе Ьееn idеntifiеd thаt havе thеsе еffесts. Traits with nеgаtivе еffесts only on thе old сan еvolvе in populations through gеnеtiсdrift (i.е.,thе aссumulаtion of dеlеtеriousmutirtions). Мorе powеrful mathеmatiсal tools, nеw tесhnologiеs (е.g.,gеnomiсs), and moгеinsightfulеxpеrimеnti.ttion аге pегmittingЬiologiststo Ьеttеrundеrstand lifе-history variation within and аmong spесiеs and thе rolе of suсh variation in gеnеratingnеw spесiеs.Thе rеsulting insights arе inсrеasinglyЬеing translatеd into tlrе appliеd sсiеnсеs whеrе Ьiologists arе studying how lifе.history еvolution influеnсеs thе сonsеrvation of Ьiotiс rеsourсеs,thе yiеld and thе sustainaЬilityof agriсulturе,and how thе еvolutiсlnof ontogеny, rеproduсtion, and disеasеrеlatеs to human hеalth.

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570 Еuolution of Seх вlвLIoGRAPнY Сaгroll,s. P.' A. P. Hеndry,D. N. Rеzniсk,and С. W. Foх. 2007.Еvolutronon есologiсaltimе-sсalеs.FunctioпаlЕcologу 21: З87-З9З. Сharnov, Е. L., and W. A4. Sсhaffer. 1973.LIiе-historyсonsеquеnсеs of natural sеlесtion:Сolе's rеsultrеvisitеd.Amеriсап Nаtиrаlist|oi| 79]..-79З. Сolе, L. С. |954. Thе populatiollсonsеquеnсеs of lifе historypь.no.й". Quаrtеrlу Rеuiеcuof Biologу29: |0З_137. Godfraу,H. с. J., L. Partridge,and P. H. Harvеy.1991.Сlutсh sizе.Аппцаl Rеuieш of Есologу апd Sуstеmаtics22: 409429, Hutсhings,J. A.' аnd D. J. Frasеr.2008. Thе naturеоf fishеriеsand farminginduсеdеvolution.Мolесulаr Еcologу 17:294-З13. Laсk, D. 1947.TЬеsignifiсanсе of сlut.Ё.i,.. Ibis89: 3o9-з52. oгzaсk, S. H.' and Е. SoЬег.1994.optimаlitymodеlsand thе tеstof ас1aptatlon. АmeriсапNаturаlist143:361-380. Roff' D' ^. |992. Тhе Fuolutioп of Lifе Historiеs:Thеorу апсlАnаlуsis.Nеw Yoтk: Сhapmаnand Hall. Smith,C. С., and S. D. Frеtwеll, 1974.Thе optimal Ьalanсе Ьеtwееnthе srzеand numЬеrof offspring.Ameriсап Nаturаlist 108: 499-506. Vаndеr.!иеrf, Е. 1992.Lасk,sсlutсh sizе hypothеsis:An ехaminatiorrof thс еvidеnсе usingmеta-ana|ysis. Есologу 73:1699_1705. -s.P.С' апd С.\Y.F.

Еvоlution of sех Hеrе,you seе,it takеsall thе runningyou саn do, to kееp in thе sanrе plaсе. _Тhе Rеd Quееn,in Lеwis Сarгoll's Throughthе Looking Glаss(1872)

of thе many mеanings of thе word se*' thе most fundamеntal rеfеrs to thе produсtion of nеw gеnomеs by thе rесomЬination of prеехisting gеnomеs. Мany baсtеria and a fеw virusеs arе сapablе of oссasional. limiйd sех' Ьut thе-most thoroughly sеxual сrеaturesarе thе еukаryotеs, whiсh inсiudе animals' plants' and othеr organisms with nuсlеi in thеir сеlls. Humans arе fairly typiсal еukaryotеs in Ьеing oЬligatеly sехuаl: thе only wаy to mаkе а nеw human is to split your gеnomе in half and to gеt anothеr lrali from somе othеr Ьuman who has donе thе same. Dеspitе thе сеntral rоlе that sеx plays in organismal lifе сyсiеs, Ьiologists do not undеrstand what its funсtion is. Thе first biologist to suggеst a plausiЬlе hypothеsis for tlrе аdvantagе of sеxuality was August.V7еismann(1ss9). Hе proposеd that sех inсrеasеdthе vaтiability within a population and thus inсrеasеd thе еffесtivеnеssof natural sеlесtion. This is an unusual sort of advantagе; typiсally, natural sеlесtion promotеs traits that сonfеr an advantagе to thе individual that Ьеars thе trait. .!(i'еismann' howеvеr, saw sеx as a fеaturе of a populatiоn that сonfеrrеd an advantagе to that population. .sИеismann'seхplanation was influеntiai аnd wеnt largеly unсhallеngеd until thе 1960s, whеn Gеorgе С. Williams oЬjесtеd to its rеlianсе on 8roup sеlесtiоn and insistеd thаt sеx should hаvе а short-tеrm, individual-lеvеl аdvantаgе likе аny other trait. On thе сonrrarv.

sе-хsееlnеd to hirvе сlonirl fеmalе trans mаle trаnsmits onl1 hаlf of hеr parеntа malе' Thus sех сarri hugе thеorеtiсal dis Ьeеrl сallеd ..thе pа; spurrеd sеvеral lеad highligliting thе imp lutionary Ьiology'' ( fits of sеxuality' it rv twiсе as fit, on avеrа quirеd to Ovеrсomе1 viduals сan havеthi in a world that сhal сally, sех сan outс() (1) kills a lаrgе рrсlр fесt oп геpгoduсtion dividuals wit]r сеrtаir (З) сhangеs rirdiсally tyреs arе killеd and l tion for sех, thе ph world, аffесting mosl Ье? In rесеnt dесаdе disеasе (Hamilton 20 Thе idеa thаt infес makе sех аdvаntаgе thе аspесts of an orgа thе thеorists' dеsсrip Bесацsе parаsirеs an quiсkly сomparеd to gеnotypеs. onе striki tions should oссurinarе сommon in onе Quееn hypothеsishas iсs of hosts and para flеаs, Ьut sсiеntistsdс to Ье. Thе othеr phеnon-r ful mutation. With hi rесonrbirrant offsprin This is orriy truе if rat' individuаl сarryiпg
Еuolutioп of Sех

\W.Foх.2007. Еvolution on з87-39з. 'ory сonsеquеnсеsof nаtural urаIist107l791_793. .ifеhistory phеnomеna. Quаrterlу l991. Сlutсh stze.AпnцаI Reuiеtu е оf fishеriеs-and farming-3 13. 8 9 :3 0 9 - 3 5 2 . iеls and thе tеst of adaptation. Тbеorу апd Апаlуsis. Nеw York: Ll Ьalanсе Ьеtwееn thе sizе and i:499-506. ;:An еxamination of thе еvidеnсе

-s.P.C. апd С''\Y.F.

tn do,to kееpin thе sаmе .еdQuееn,in Lеwis Саrroll's щh thеLookiпg Glаss (|872|

most fundamеntal rеfеrs to thе nation of prеехisting gеnomеs. э of oссasional, limitеd sеx, but :еukaryotеs,whiсh inсludе aniсlеi in thеir сеlls. Humans arе sехual:thе only way to makе a rd to gеt anothеr half from somе tе the сеntral ro1еthat sеx plays n d е r s t а n dw h а t i t s f u n с t i o n i s . hypothеsisfoг thе advantagе of propоsеd that sеx inсrеasеd thе еasеdthе еffесtivеnеssof natural tagе; typiсally, natural sеlесtion hе individual that Ьеars thе trait. f a population that сonfеrrеd an ехplanation was influеntial and \й/illiams oЬ, whеn Gеorgе С. 1 insistеd that sеx should havе a 1ny othеr trait. On thе сontrary,

sехsееmеdto havе an еnormous short-tеrm,individual-lеvеldisadvantagе.A сlonal fеmalе transmits all of hеr gеnеs to all of hеr offspring. A sехual fеmalе transmits only half аs many gеnеs to thе nеХt gеnеrаtiоn, and wаstеs half of hеr parеntal invеstmеnt propagating thе gеnеs of somе unrеlatеd malе.Thus sех сarriеs an еnormous (twсlfold)сost. Thе сontrast Ьеtwееnthis hugеthеorеtiсaldisadvantagеof sеx and its pгеvalеnсеin thе rеal world has ..thе pаrаdox bееnсallеd of sех.'' In thе 1970s, rесognition of this paradoх lеading spurrеdsеvеral еvolutionary thеorists to Writе hand-wringing Ьooks highlightingthе importanсе and diffiсulty of this ..queеnof proЬlеms in еvo. lutionaryЬiology'' (Bеll 1982). Though it was еаsy ro imаginе possiЬlе Ьеnеfitsof sехuality,it wаs hard to sее how sехual individuals сould Ье morе than twiсе аs fit, on avегagе,as asеxual individuals, whiсh is what sееmsto Ье rе. quirеd to ovеrсomе thе twofold сost of sех. Thеorists found thаt sеxual individuals сan havе this magnitudе of advantagе Ovеr asеxual individuals only in a world that сhangеs radiсаlly from onе gеnеratiоn to thе nеxt. spесifiсally, sех сan outсompеtе asехuality only if thеrе is somе phеnomеnon that (1)kills a largе proportion of еaсh population, or has an еquivalеntly dirе еffесton rеproduсtion; (2) is sеnsitivеto variation Ьеtwееngеnomеs'killing individualswith сеrtain gеnotypеsand sparing thosе with othеr gеnotypеs;аnd (3)сhangеsradiсally frоm сlnеgеnеrationtO thе nехt in tеrms of whiсh gеnotypеsarе killеd and whiсh arе sparеd. Furthеr, to providе a gеneral eхplanation for sеx' thе phеnomеnon would hаvе to Ье uЬiquitous in thе living world, affесtingmost multiсеllular organisms.What сould this phеnomеnon Ье?In rесеnt dесadеs,two major сandidatеshavе Ьееn rесognizеd:infесtious disеasе(Hаmilton 2001) and harmful mutаtions (Kondrashov 2001). Thе idеa that infесtious disеasеs,сausеd Ьy parasitеsand pathogеns,сould makе sех advantagеousis oftеn known as thе Rеd Quееn hypothеsis.of all thе aspесtsof an organism'sеnvironmеnt' its parasitеsand pathogеns Ьеst fit thе thеorists'dеsсription of thе phеnomenon that givеs an advantagе to sех. Bесausе parasitеs and pathogеns havе largе populations and rеproduсе quiсkly сomparеd to thеir hosts, thеy сan еvolvе to attaсk partiсular host gеnotypеs.one striking prеdiсtion of thе hypсlthеsis is that strong fluсtuations should oссur in thе frеquеnсiеsof allеlеsaffесtingimmunity; allеlеsthat arе сommon in onе gеnеration should Ьесomе rarе in thе nехt. Thе Rеd Quееn hypothеsishas Ьееn suссеssfulin ехplaining thе еvоlutionary dynamiсs of hosts and parasitеs in а fеw wеll-studiеd spесiеs of snails and watеr flеas,Ьut sсiеntistsdo not yеt know how Ьroadly appliсaЬlе it will turn out to Dе.

Thе othеr phеnomеnon with thе potеntial to makе sех nесеssaryis harmful mutation. \X/ithhigh mutation ratеs' sех сan Ье Ьеnefiсial Ьесausе somе rесombinant offspring will сarry fеwеr harmful allеlеs than еithеr parеnt. This is
.t71

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Ешeпs to havе a high еnough ratе of harmful mutation to makе sеx usеful, Ьut thе ratе sееms to Ье too low in Worms and fliеs. An important dеtail is that sех only hеlps to inсrеase avеragе fitnеss if hzrrmful allеlеs intеraсt synеrgistiсally, that is, if thеy bесomе pгoportiоnatеly nrorе haгmful as morе of thеm ассumulatе in a gеnomе. A wеaknеss of thе mutation thеory is that it doеs not sееm to aссount for есologiсal pattеrns in thе distriЬution of asехual linеagеs as wеll as thе Rеd Quееn hypothеsis dоеs. \JИhеna gеnomе rеpliсatеs, it tеnds to dеtеrioratе. Мutations oссur and thеy tеnd to Ье harmful. Thе еnvironmеnt also tеnds to gеt Worsе from yеaг to yеar: your еnemiеs gеt Ьеttеr at attaсking you, еspесially parasitеs and pаthogеns with short gеnеration timеs that еvolvе rapidly to adapt to your gеnotypе. Thеsе two proсеssеs tеnd to makе mаintirining а statiс gеnomе Ьoth diffiсult (duе to mutation) as wеll as a Ьad idеa (duе tсl parasitеs).Sех sееms to Ье an adaptation to dеal with onе or anothеr of thеsе proЬlеms, or pеrhaps to dеal with Ьoth of thеm at onсе. Thеrе has Ьееn a rесеnt trеnd toward сomЬining thе Rеd Quееn and mtrtational mоdеls and rесognizing tЬat sеx has n-rultiplеadvantagеs.Еvеn Gеorgе Williams, whosе quеst for an individual-lеvеl advantagе of sеx launсhеd thе modеrn study of its еvolu. tion, hаs сonсеdеd that its spесiеs-lеvеladvantagеsmight Ье сruсial aftеr all (Williams 1992|. Asеxual spесiеssееm to bе muсh morе pronе tсl еxtinсtion . е n с е , m o s t s u г v i v i l l gs p е с i е sa r е s е x u a l ,а n d m a n y , i n than sехual spесiеsH сluding mammals, sееm tO hаvе fеaturеs that prеvеnt thеm fгom еvеr Ьесoming asехual. Although thе proЬlеm of sеx has rесеntly bееn rеduсеd from a mystеry to a mеrе сontrovеrsy' sсiеntistsstill nееd a good dеal morе infоrrnation to undеrstаnd еxасtly how sеx hеlps irrdividual oгganisms to havе morе suссеssfuloffspring and how it prеvеnts populations from going ехtrnсt. B|вLIoGRAPнY Bеll, G. 7982. Тbе Маstеrpiесеtf Nаturе.Bеrkеlеy:Univеrsityof Саlifornia Prеss. Нamilton,!и. D. 2001.Nаrrot,tlRсlаdsof GепeLаnd.Уol,2,Тhе Еuolutioпof Seх, oxford: Oхford UnivеrsiryPrеss. Judson,o.2.002. Dr. Tаtiапа'sSехАduiсеto АIl Сrеаtiои.Nеw York: Меtropolitan Books. K с l n d r a s h о vA,. s . 2 0 0 1 .S е ха n d U . T r e п d si n G е п e t i с s1 7 : 7 5 _ 7 7 ' Ridlеy, \'4, 1994. Thе Rеd Quеeп: Sехапd tbе Еuolutioп of Humап Na,иre. Nеw York: Мaсmillan. \Wеismаnn, A. 1889. ЕssауsupсlttHerеditуапd Kiпdrеd BiologiсаlProblems, Oхfoгd:СlаrеndonPгеss. Domаiпs, Lеuеls,апd СhаIleпges.oхford: Williams, G. С. 7992.Nаtиrаl Sеlесtiсlп: -B.B.N. Oxford UnivеrsitvPrеss.

'Warrеn Еwеns, J. (b. 1937) Although thеy may sееm еsotеriс at first glanсе' many of thе stirtistiсal aspесts of pоpulation gеnеtiсs'suсh as thе prесisеdistriЬr'rtionof fitnеssamong

altеrnativе forпrs of a сhangеs unfold in еvolu morе thorolrghly or сarс dation of sеvегаlаrеas с T r а i n е d i n s t а t i s t i с а1l rесеivеd his doсtoral dед who was a studеnt of S work on thе samplirrg< havе no еffесts on thе fit opеd Ьy Motoo Kimur ..Motoo Kimura'' аnd .. bioсhеmiсal and r-nolе s p е с i е s .O n е o f t h е с r i t i t сal distriЬution of allеlе triЬutions еxpесtеd und' Еwеns dеrivеd thеsе ех aЬout thе nattlrе of mut to Ье сallеd, not Only al piriсal data' but also p thеorеtiсal advanсеs wt пеutral thеory аnd the с allеlеs among a sеt of nс and gеnе flow. Thrее of Еwеns's otl i n г е r p r е г i n gг h е g е l r е г i allеlе аvailaЬlе in a popl pеndеd on thе prесisеst nеtiс load lays bеnеath thе so-сallеd Наldаnе's сost of so many unfit gе indееd nеutral. Еwеns's еntiststhought aЬout th for thе еffесtivе populаt arе rеally сontributing t еas of сonfusion, еspесt populаtion sizе, a quest his с
Еъueпs 57З )n to makе sех usеful' Ьut thе \n important dеtail is that sеx I al1еlеsintеraсt synеrgistiсa1ly, rarmful as morе of thеm aссuLtionthеory is that it doеs not jistribution of asехual linеagеs эrioratе.Мutations oссur and o tеndsto gеt worsе from yеar i you, еspесially parasitеs and volvе rapidly to adapt to your е maintaining a statiс gеnomе lad idеa (duе to parasitеs). Sеx г anothеrof thеsе proЬlеms, or rеrе has Ьееn а rесеnt trеnd to:ionаlmodеls and rесognizing ;е.!Иilliams,whosе quеst for an ;hе modеrn study of its еvolurtagеs might Ье сruсial aftеr аll muсhmorе pronе to еxtinсtion r е с i е sа г е s е х u а l ' a n d m a n y ' i n at prеvеnt thеm from еvеr Ьеsех has rесеntly Ьееn rеduсеd :istsstill nееd a good dеal morе hеlpsindividual organisms to r е v е n t sp o p u l a t i o n sf r o m g o i n g

:y:Univеrsityof Сalifornia Prеss. ,апd.Уo|.2,TbеЕuolutionof Seх. Сreаtioп.Nеw York: Меtropolitan эпеtiсs17,.75-77 , ,tolutioпof Ниmап Na'иre. Nеw 'iпdredBiologiсаlProblеms. к, Lеuels,апd Сhаllепges.oхford: -B.B.N.

|anсе,many of thе statistiсal asсisе distriЬution of fitnеss among

altеrnativе forms of a gеnе' play vital rolеs in dеtеrmining how gеnеtiс сhangеs unfold in еvolution. Fеw sсiеntists havе unсovеrеd thеsе vital rolеs morе thoroughly or сarefully than \WarrеnJ. Еwens, whosе work is thе foundаtion of sеvеral arеas of rеsеarсhin еvolutionary population gеnеtiсs. Trainеd in statistiсal gеnеtiсs at thе Australian Nаtional Univеrsity, Еwеns rесеivеdhis doсtoral dеgrееtn 1964 undеr thе supеrvisiоn of P. A. P. Moran, who was a studеnt of Sir Ronald Fishеr. Еwеns is known primarily for his work on thе sampling distriЬution of nеutral allеlеs, whiсh arе allеlеs that havе no еffесts on thе fitnеss of thеir сarriеrs. Thе nеutral allеlе thеory dеvеlopеd by Мotoo Kimura and Tomoko Ohta (seе thе alphaЬеtiсal еntriеs ..Motoo Kimura'' and ..Tomoko Ohta'' in this volumе) wеddеd thе study of Ьioсhеmiсal and molесular polymorphisms to pattеrns of variation among spесiеs.Onе of thе сritiсal tеsts of this thеory сomparеd thе oЬsеrvеd statistiсai distriЬution of allеlе numЬers and frеquеnсiеs at a singlе gеnе to thе distriЬutionsехpесtеd undеr nеutrality. In a sеriеsof papеrs in thе еarly \970s, Еwеns dеrivеd thеsе ехpесtеd distriЬutions undеr a variеty of assumptions aЬout thе naturе of mutations. Thе Еwеns Sampling DistriЬution, as it сamе to Ье сallеd, not only allowеd thе nеutral thеory to Ье еvаluatеd against еmpiriсal dаtа, Ьut also providеd thе foundation on whiсh sеvеral additional thеorеtiсal аdvanсеs wеrе Ьuilt. Thеsе inсludеd various rеfinеmеnts of thе nеutral thеory and thе dеvеlopmеnt of mеthods for using thе distriЬution of allеlеsamong a sеt of nеighЬoring populations to еstimatеratеs of migration and gеnе flow. Thrее of Еwеns's othеr сontriЬutions stand out. First, hе showеd how intеrprеting thе gеnеtiс load, thе diffеrеnсе Ьеtwееn thе fitnеss of thе Ьеst allеlеavailaЬlе in a population and thе avеragеfitnеssof all othеr allеlеs,dеpеndеd on thе prесisе statistiсal distriЬution of fitnеss. Thе сonсеpt of thе gеnеtiс load lays Ьеnеath sеvеral сontrovеrsiеs in еvolutionary gеnеtiсs, from thе so-саllеd Haldanе's dilеmma (how сan an еvolving population Ьеar thе сost of so many unfit gеnotypеs)to thе likеlihood that molесular variation is indееdnеutral. Еwеns's сritiсal study of thе gеnеtiсload сhangеd thе way sсiеntiststhought about thеsеissuеs.Sесond,Еwеns dеrivеd prесisе ехprеssions for thе еffесtivе population sizе, whiсh is a mеasurе of how many individuаls arе rеally сontriЬuting to thе nехt gеnеration. This work сlarifiеd sеvеral arеas of сonfusion, еspесially surrounding thе еffесt of сatastrophiс dесrеasеs in population sizе, a quеstion of intеrestin сonsеrvation Ьiology. Third, hе and his сollеaguеs dеrivеd nеW mеthods for dеtесting assoсiations Ьеtwееn gеnеs and human disеasеs,mеthods that solvе long-standing statistiсal proЬlеms Ьasеdon thе nonгandom samplеs that еmеrgе from mеdiсal rесords. Е w е n s h a s a I е g е n d а г yг е p u t a t i o nа s а s u p е r Ь l е с t u г е ra n d с l a s s r o o m i n struсtor. Hе has inspiгеd gеnеrations of studеnts throughout his сarееr in Australia, primаrily at LaTroЬе Univеrsity, and in thе Unitеd Statеs at the Univеrsityof Реnnsylvania.Hе rесеivеdthе Е. J. Pitman Меdal from thе StatistiсalSoсiеty of Australia ln 1996 and' in 1999,Ьewas еlесtеd as a fеllow of thе Royal Soсiеty.

574

Ехobiologу в|вLIoGRAPHY Еwеns,!и. J. 2004. МаtbеmаtiсаlPopulаtiопGeпеtiсs.2ndеd. Nеw York: Springеr. .VИ. Еwеns' J., and G. R. Grant. 200|. StаtistiсаlМеthodsiп Bioinformаfiсs.Nеw -IT York: Springеr.

Ехobiology With thе advеnt of spaсе ехploration, two fiеlds of rеsеarсh-origin.of-lifе studiеs аnd thе sеarсh for еХtratеrrеstrial lifе-wеrе mеldеd into a singlе nеw disсiplinе. In 1959, NoЬеl Pгizе_winning miсroЬiologist Joshua LеdеrЬеrg сoinеd thе tеrm eхobiologу for this nеw intеrdisсiplinary fiеld, offегing thе rationalе that onе nееdеd to know thе сonditions undеr whiсh lifе,s origin had Ьееn possiЬlе on еarth in ordеr to know what kind of сhеmiсal сonditions to look for on othеr planеts. Furthеrm
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:lds of rеsеarсh-origin-of-lifе .wеrе mеldеd into a singlе nеw эroЬiologistJoshua LеdеrЬеrg гdisсiplinary fiеld' offеring thе tions undеr whiсh lifе's origin what kind of сhеmiсal сondi. 'rе,hе arguеd that stеrilization 1 o t h е rp l а n е t s 'l е s t с o n t a m i n a n organiсmolесulеs from еarth . r a i n t yw h а t k i n d o f n a t i v е o r v . A t f i r s t l а r g е l yа n A m е г i с а n SpaсеAdministration (NASA) in thеsеarеashad thе potеntial thе sсiеnсеrеlatеd to spaсе еxэtivе,for еxamplе, aЬout what . . dr o i t s i n t е r p l a n е t a r ym i s s i o n s on' Vеnus' and Mars. Similarly, row its еxpеrtisе in stеrilization h ' G r a d u e l l у .h o w е v е r .i n t е r n a ,mmittее for Spaсе Rеsеarсh г stеri1izationstandards, еvеntuTrеaty.Intеrnational origin-ofэ o n s o r е dm е е t i n g so n t h е o r i g i n a n p а l е o f o s s i I sa.n d o t h е r t o p i с s :ommunityof sсiеntistsworking :mistry,gеoсhеmistry' p1anеtary first еxoЬiology iournal Ьеgan Еuolutioп of thе Biсlspberе).|л ;sionalsoсiеty,thе Intеrnational ) L ) .o n l y w i t h t h е t е с h n o l o g yo f would it Ьесomе possiЬlе to dеo undеrstand(or tеst) what unilutionaryhistory. aсadеmiсlaЬoratory rеsеarсh as :nts to flу on spaсесraft, suсh as Lеsесraft found no сlеar еvidеnсе :noughdata to suggеst that if lifе эе found dееp еnough Ьеlow thе ays.In addition,thе dеvеlopmеnt

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Beingsfrom outеr spaсе havе long Ьееn thе stuff of fantasy and nightmаrе.This .!Иеlls,..Thе Things That Live drawing,Ьy !7illiam R. Lеigh, appеarеdin H. G. on Мars'', СosmopolitапМаgаziпe,Marсh 1908, 3З5_343.It appеarеdjust ..сanals'' at thе timе whеn thеrеwаs muсh popular disсussionаЬout whеthеrthе Notе how oftеn suсh piсturеs on Маrs Wеrеthе produсtsof rеal intеlligеnсеs. assumеthаt еvolutionis progrеssivеаnd nonсontingеnt,with humanlikеforms thе inеvitaЬlеoutсomеof thе proсеss,anywhеrеand еvеrywherе.

575

576

Ехobiologу of radio astronomy tесhniquеs to sеarсh for signals from intеlligеnt ехtratеr. rеstrials (SЕTI) was part of ехoЬiology fronr thе outsеt, although Сongrеss сut off NASA funding for SЕTI woгk in 1992. Bу thе 1980s and 1990s, nеw astronomiсal tесhniquеs wеrе dеvеlopеd to sеarсh for planеts of stars Ьеyоnd thе solar systеm' with thе first suсh planеt Ьеing dеtесtеd in 1995. LaЬoratory work has puгsuеd numеrous goals, inсluding study of thе organiс сompounds foцnd iп metеoritеs, геturnеd moon гoсks, and (via spaсесraft) сomеts' and study of anсiеnt roсks for fossilizеd miсroЬеs аnd/or organiс molесulеs that might Ье аssoсiatеd with onсе-living organisms. This work has lеd to pushing baсk to 3 Ьillion yеars or morе thе oldеst known fossil miсroЬеs from еarth, narrowing thе timе window foг thе proсеss of сhеmiсal еvolution to havе oссurrеd. Howеvеr, it has simultanеously rеvеa[еdthat еarth is Ьеing bomЬardеd Ьy organiс molесulеs formеd in hugе irmounts in intеrstеllar spaсе' so that thе original prесursors of lifе on еarth nееd not all havе bееn synthеsizеd hеrе from purеly inorganiс starting matеrials. ЕхoЬiology rеsеarсh has also spun off numеrous othеr important disсovеriеs: Lynn Мargulis's thеory, now univеrsally aссеptеd, that еukагyotiс сеlls arosе via .Woеsе's formation of sеrial symbiotiс сoloniеs of pгokaryotiс сеlls; Carl disсovеry of thе Arсhaеa' a groцp of Ьaсtеria as diffеrеnt from othеr Ьасtеria as thеy arе from еukaryotеs; Jamеs Lovеloсk's Gaia hypothеsis, whiсh сlaims that all lifе on еarth aсts as a сoordinated homеostatiс systеm maintаining сonditions within thе limits lifе саn tolеratе; thе thеory that a hugе аstеroid impaсt at thе еnd of thе Сrеtaсеous pеriod was rеsponsiЬlеfor thе mаss ехtinсtion that inсludеd thе dinosaurs; and thе ..nuсlеar wintеr'' hypothеsis, pгеdiсting that a similar mass ехtinсtion сould follow a nuсlеar War of any signifiсant sizе, and spurring on muсh of global сlimatе modеling sсiеnсе. Thе broаdеning of thе rеsеarсh agеnda rеsultеd in thе еxoЬiology fiеld Ьеing rеnamеd astroЬiology in 1996. Following thе Soviet bioсhеmist Alеksandr Oparin, origin-of-lifе rеsearсh assumеd in thе 1950s that еarth's primitivе atmosphеrе must havе Ьееn сhеmiсally rеduсing' that is, it сontainеd no frее oхygеn' сarbon mostly аs mеthanе, and nitrogеn as ammonia. Thе 1953 Urеy-Millеr еxpеrimеnt showеd that Spontаnеous synthеsis of amino aсids and othеr rеlеvant Ьiomolесulеs сould oссur rapidly undеr suсh сonditions, еvеn assuming rzrndom сhеmistry. By thе latе 1970s, howеvеr, еxoЬiology rеsеarсhsuggеstеdеarth's еarly atmosphеrе was morе likеly to havе Ьееn сhеmiсally nеutral (or pеrhaps еvеn slightly oхidizing), undеr whiсh сonditions thе synthеsisof organiс molесulеs is drastiсally rеduсеd. Altеrnativе pathways of сhеmiсal еvolution arе undеr invеstigation, inсluding synthеsis of organiс polymеrs using сlays as tеmplаtеsand саtalysts;high-tеmpеratLlrе, high-pгеssurесhеmistry suсh as might oссur at undеrsеa hydrothегmal vеnts, whеrе many rеsеarсhеrs now think lifе may have first originatеd; and сomЬining mеtеoritе-dеrivеd organiсs to sее what kinds of lifеlikе protoсеlls will Ье produсеd. It is now widеly bеliеvеd that thе сhеmistry thаt lесl frоm inorganiс prесursors to tlrе first biopolymеrs oссurs nonrandomly' morе rapidly, and spontanеouslyundеr а widеr ransе of сonditions than was Ьеliеvеdin thе 1950s and 1960s' Biasеd

in thе dirесtion of Ьiol. faiгly quiсkly Ьut ..nеith statеs(2000, 109).Il.еs еarly in lifе's history wl aсting as Ьoth an inforr lism. в|BLIoGRAPHY

Diсk' S., and J. Е. Striсk.2 Аstrobiologу.Nеu, Br Fry, I. 2000. The Еmеrgеп О uеruiеt'l,,. Nеw BruIl Grаhurm,L. 1987,Sсiепсе Nеw York: СolurnЬrа Наzеn, R. 2005. Gепesis: Hеnry Prеss. L е d е r Ь е г gJ ., l 9 6 0 . Е х о h i з9з40О. L о v е l o с kI, . 1 9 7 9 . G а i а :А Prеss. Mllгgu|is.L. |970.origin Prеss. М i I l е r 's . I 9 5 3 .A p r o d t r с сonditions.Sсieпсе|1 o p а г i n , A . l 9 3 8 . T h еo r i g 'W.оеsе, С. 1987.Bасtеrialt Wolfе,A. 2002. Gеrmsin s imagination,1958-19

Ехobiologу ]nalsfrom intеlligеnt еxtratеr:hе outsеt,althougЬ Сongrеss B y t h е 1 9 8 0 sa n d 1 9 9 0 s , n е w гсh for planеtsof stars bеyond ing dеtесtеdin |995. LaЬorat i n gs t u d yo f t h е o r g a n i с с о m t roсks, and (via spaсесraft) i z е d m i с r o Ь е sа n d / o r o г g a n i с э-living organisms' This work эrе thе oldеst known fossil miw for thе proсеss of сhеmiсal simuitanеouslyгеvеalеd thаt е s f o г m е di n h u g е a m o ц n t s i n ,rsof lifе on еarth nееd not all riс startingmatеriаls.Еxobiol:r important disсovеriеs: Lynn t h a t е u k a г y o t i сс е l l s a г o s е v i a aryotiс сеlls; Сarl Woеsе's dis_ Iiffеrеntfгom othег Ьaсtеriа аs Эaia hypothеsis,whiсh сlaims l m е o s t а r i сs y s t е m r n а i n г a i n i n g hе thеory that a hugе astеroid rs rеsponsiЬlеfor thе mass еx..nuсlеarwintеr'' hypothеsis, d follow a nuсlеar war of any l Ь a l с l i m a t еm o d е I i n g s с i е n с е . ld in thе ехoЬiology fiеld Ьеing oparin, origin-of.lifе rеsеarсh l atmosphеrе mllst havе Ьееn frее oxygеn, сarЬon mostly as l953 Urеy-Мillеrеxpеrimеnt aсids and othеr геlеvant Ьioditions, еvеn assuming random 'logy rеsеarсh suggеstеd еarth's :еnсhеmiсally nеrrtral (or pеrd i t i o n st h е s y n t h е s i so f o r g , а n i с ,аthwaysof сhеmiсal еvolution f organiс polyrnеrs using сlays сhemistry suсh as righ-prеssurе , whеrе many rеsеarсhеrs now lining mеtеoritе-dеrivеdorgan[ Ье produсеd. It is now widеly organiс prесursors to thе first lly, and spontanеouslyundеr a n t h е 1 9 5 0 sа n d 1 9 6 0 s . B i a s е d

in thе dirесtion of Ьiologiсally rеlеvant molесulеs' lifе proЬaЬly originatеd fairly quiсkly Ьut ..nеithегЬy сhanсе nor dеsign,''as sсiеnсеhistorian Iris Fry stаtеs(2000, 109). Rеsеarсh has also foсused on thе RNA world, а period еarly in lifе's history whеn RNA ехistеd Ьеforе protеins Ьut was сapaЬlе of aсting as Ьoth аn information-сaгrying rnolесulе and a сatalyst of mеtaЬolism. BlBLIoGRAPнY Diсk' S.' and J. Е. Striсk.2004. The Liuiпg Uniuеrse:NASA апd thе Deuelopmentof Аstrobiologу.Nеlv Brunswiсk'NJ: RutgеrsUniversityPrеss. Fry, I. 2000. Thе Еmеrgепсеof Life сln the Еаrth: A Historiсаl апd Scientifiс ouеruiеtll.Nеw Brtrnswiсk,NJ: RutgеrsUnivеrsityPrеss. Grаham'L. |987. Sсiеtlсе,Philosophуапd Нllmап Bеhаuioriп tbе Souiеt IJnion. Nеw York: СolumbiаUnivеrsityPrеss. Hazеn,R. 2005. Gепеsis:Тhe SсiепtificQuеst fсlr Lifе's Оrigins. Nеw York: Josеph Неnrу Prеss. LеdеrЬеrg, J. 1960.ЕхoЬiology:Approaсhеsto lifе bеyondthе еarth.Sсiепсе|32: З93400. Lovеloсk,J. 1979. Gаiа: А Nеtu l-ooh аt Lifе oп I,аrtb.London: Oхford University Prеss. Мargulis' L. 1970. Оrigiп of Еukаrуotiс Сelis.Nеw Нavеn' СT: Yalе Univеrsity Prеss. Мillеr,S. 19.5з.A produсtiorr of аminoirсidsurrdеrpossiblеprimitivееarth сonditiоns.Sсieпсе||7 : 528*529. oparin,A. 1938.Tlrc Оrigiп of Lfe. Nеw York: Maсmillаn. .Woеsе, С. 19 87. Bасtеrial еvolution.Мi cro bi ol сlgi саl Rеuiеt't-t s 5 1': 221'-271'. \(olfе,A. 2002. Gеrms in spaсе:Amеriсаn lifе sсiеntists,spaсеpoliсy, and puЬliс imagination, 19 58-1964.lsis 93: 183-205.

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Fеlsеnstеin, Josеph(ь. t942) Although all sсiеntistsaspirе to сl-rilngеhow thеir сollеаguеsthink aЬсlut an issuе, only а fеw managе to do so. A sеlесt fеw сhangе thеir сollеaguеs' thinking on moге than onе issuе.Josеph Fеlsеnstеinhas сhangеd thе thinking of еvolutionary Ьiologists on at lеast thrее сritiсal issuеs. A studеnt of pсlpulation gеnеtiсist Riсhard Lеwontin, Fеlsеnstеin wrotе his dissеrtation on mеthods for infеrring phylogеniеs' rесеiving his doсtoral dеgrее in 1968 from thе Univеrsity of Сhiсago' Aftег postdoсtoгal work at Еd_ inЬurgh with Alan RoЬеrtson, hе dеvotеd thе е:rrly yеars of his сaгееr to population gеnеtiсs;his dissеrtationrеsеarсhdid rrot appеar in sсiеntifiсjournals until 1'97З. А'fter this rеfraсtory pеriod' hе rеturnеd to thе study оf phylogеnеtiс mеthods and has madе sеminal сontriЬutions to phylogеnеtiсs and population gеnеtiсs'along thе W^ypromoting a synthеsisof thе two. Fеlsеnstеin pionееrеd a stаtistiсal approaсlr to phylogеnеtiс infеrеnсе (sее ..Phylogеnеtiсs'' in this volumе). Hе rесognizеd that, thе alphaЬеtiсal еntry whеn infеrring a phylogеny' not only would thе lеngths of thе branсhеs Ье subjесt to sampling еrror, Ьut so would thе aсtual shapе of thе еntirе trее. Sampling еrror introduсеsunсеrtaintyaЬout thе idеntity of сlosе rеlativеsand rесеnt сommon anсеstors'whiсh in turn сrеatеsunсеrtаinty aЬout thе ordеr of аppеaranсе of major fеaturеs in groups likе birds or fish. Nеitlrеr traditional mеthods Iror thе еmеrging сladistiс mеthods сonfrontеd this pгoЬlеm satisfaсtorily. Fеlsеnstеin introduсеd thе statistiсal tесhniquе of maхimum likеlihood to thе study of phylogеniеs. Thе initial rеluсtanсе of еvolr-rtionary biologists to еmЬraсе thе tесhniqt1еWas ovеrсomе whеn Fеlsеnstеinshowеd that сladistiс mеthods would point to thе wrong phylogеny wlrеnеvеr diffеrеnt branсhеs of an еvolutionary trее ехpеrienсеd suffiсiеntly diffеrеnt ratеs of сharaсtеr еvolution. This rеsult has Ьесomе a tехtЬook еxamplе, and maхimum likеlihood arrd rеlatеd mеthods havе Ьесomе thе standard approaсhеs for undеrstanding еvolutionary rеl:ltionships. Biologists aге now fоllоwing Fеlsеnstеin'slеad on two othег topiсs that еmеrgеd from his synthеsisof phylogеnеtiсsand population gеnеtiсs.In thе |ate 1.97Оs,sеvегаl еvolutionary Ьiologists pointеd out that traditional сomparisons of сharaсtеr аssoсiations among spесiеs сould Ье misintеrprеtеd bесausе suсh сomparisons did not rесognizе thе phylogеnеtiс rеlаtionships among thе spесiеsЬеing сomparеd. Fеlsеnstеindеvеlopеda pоwеrful nrеthod for intеgrаtingphylogеnеtiсaffinitiеsinto сompirгativеanalysеs.His mеthod,

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сallеd indеpеndеntсtl for сomparativе Ьioll populations of thе sal dеsсеndant rеlationsh long-tеrm ratеs of grr largе thе populatiсlns сollеaguеs hаvе br:еn and somе of tЬеsе Iт Ьiology. In addition to thеsс thi1t еxplorеd thе еvol tion аmong аllеlеs at whiсh tightеr :rnd lo tions) еvolvе and ехpl proсеssеs.Linkagе aп lution of sеxual rеprс in this volumе) and i ..Thе Pattеrn and Pro Hankinson in this vol |n 1'992Fеlsеnstеi е n с е s .I n 1 9 9 3 h е w a s Aпrеriсan Soсiеty ot } ti
BIBLIOGRAPH

Fеlsеnstеin, l. 2004.Iпf S l a t k i n ,М . 1 9 9 5 .Т h е S Nаtиrаlist145:ii-r

Fishеr, Ronald A

Sir Ronald Aylmеr I gl:rnd. Fishеr and his of еight сhildrеn Ьс п]athеmatiсal gifts еa lriology. Bесausе of е Indееd' somе of his n or papеr' giving Fish his hеad. Fislrеr matriсLllatе H е g r a d u a t е 6; n | 9 1 oгl for anothеr yеаr t( еsts wеrе Ьroad' inсlt | 9 | 4 h e Ь е с a m еа s t i pany in London. Сon Ьесausе of his potlr r

Fisher

thеir сollеaguеsthink aЬout an :t fеw сharrgеthеir сollеaguеs' nstеinhas сhangеd thе thinking tiсal issuеs. Lеwontin, Fеlsеnstеin wrotе his еniеs'rесеivinghis doсtoral dеAftеr postdoсtoral work at Еd:hе еarly yеars of his сarееr to did not аppеar in sсiеntifiс jourd' hе rеturnеd to thе study of l с o n t r i l r t r t i o nгso p h у l o g е n е t i с s roting a synthеsisof thе two. h to plrylogеnеtiс infеrеnсе (sее is volumе).Hе rесognizеd that, l thе lеngths of thе Ьranсhеs bе aсгual shapе of thе еntirе trее. thе idеntitуof сlosе rеlativеs and atеs unсеrtaintyaЬoшt thе ordеr likе Ьirds or fish. Nеithеr tradirеthods сonfrontеd this problеm а t i s t i с a lt е с h n i q u еo f m a x i m u m initial rеluсtanсе of еvolutionary whеn Fеlsеnstеin showеd )rсol1-lе whеnеvеr diffеrphylogеny rong rсеd suffiсiеntly diffеrеnt ratеs of a tеxtЬook ехamplе, and maxi. Ьесomеthе standard approaсhеs 's lеad on two othеr topiсs that s and population gеnеtiсs. In thе lointеd out that traditional сomspесiеsсould bе misintеrprеtеd zе thе plrylogеnеtiсrеlationships еin dеvеlсlpеda powеrful mеthod )mpаrativеanalysеs.His mеthod'

сallеdindеpеndеntсontrasts,and its dеsсеndantshavе Ьесomе standard tools for сomparativе Ьiology. In thе еarly 1990s, Fеlsеnstеin pointеd out that po;lulationsof thе sarlе spесiesarе pаrt of a сomplех pеdigrее of anсеstor_ dеsсеndantrеlationships and that, through this pеdigrее,onе сould еstimatе long-tеrmratеs of gеnеtiс ехсhаngе among populations and how gеnеtiсally largе thе populations havе Ьееn. Меthods dеvеlopеd Ьy Fеlsеnstеinand his сollеaguеshavе Ьееn appliеd to sеvеral proЬlеms in еvolutionary biology, and somе of tЬеsе mеthods hаvе Ьесomе important tools in сonsеrvation Ьiology. In addition to thеsе aссomplislrmеnts,Fеlsеnstеinwrotе a sеriеs of papеrs that ехplorеd thе еvolution of gеnеtiсlinkagе, whiсh is thе statistiсalassoсia. tion among allеlеs аt diffеrеnt gеnеs.Не ехaminеd thе сirсumstanсеsundеr whiсh tightеr and loosеr linkagе (strongеr аnd wеаkеr statistiсаl assoсiations)еvolvе:rndехplorеd ho''v сlosе linkagе affесtsa variеty of еvolutionary proсеssеs.Linkаgе аmong gеnеsis а vital еlеmеntin ехplanаtions for thе еvolution of sехual геproduсtion (sееthе alphаЬеtiсal entry ..Еvolution of sеx'' in tlris volumе) аnd it plays a сruсial rolе in spесiation (sее thе main еssаy ..Tlrе Pattеrn and Proсеss оf Spесiаtion'' by Margarеt B. Рtaсеk and Shаla J. Hirnkinson in tlris volumе). |n 1992 F.еlsеrrstеin was еlесtеdto thе Amеriсаn Aсadеmy of Arts and Sсiеnсеs.In 7993 he was thе sесond rесipiеnt of the Sеwall Wright Award of thе Amеriсan Soсiеty of Naturalists, and tn 1999 hе was еlесtеdto thе U.S. Na. tional Aсadеmy of Sсiеnсеs. BIBLIOGRAPHY Fеlsеnstеin, Sundеrland, МA: SinauеrAssoсiatеs. J.2004. lпfеrriпgPhуIсlgепies. Slatkin,M. 199.5.Thе SеwallWrightAward:JosеphFеlsеnstеin. Ameriсап -I.T' Nаtltrаlist145:ii-v'

Fishеr,Ronald Aylmеr (1890_Т962) Sir Ronald Aylmеr Fishеr was Ьorn FеЬruary 17, 1890, in London, Еngland. Fishеr and his twin Ьrothеr, who diеd in irrfanсy, Wеfе thе youngеst of еight сhildrеn Ьorn tсr Katiе Hе:rth and Gеorgе Fishеr. Showing his mathеmatiсalgiits еаrly, Fishеr would сhangе rhе fасе of Ьoth statistiсsand Ьiology. Bесausе of еxtrеmе myopia, his еarly trаining Was unсonvеntional. Indееd,somе of his most influеntial еarly tutоring was donе without pеnсil or Papеr, giving Fishег a rеmarkirblе aЬility to do сomplех mаthеmatiсs in hishеad. Fishеr matriсulаtеd at Gorrvillе and Сaius Сollеgе, СamЬridgе, in 1909. Hе graduatеdin |972 with high honors in mathеmatiсs,and he would stay on for anothеr yеar to study physiсs and statistiсalmесhaniсs.Fishеr's intеrеstsWеrе Ьroad, irrсludingastronomy' mathematiсs,physiсs, and Ьiology. In 7914 Ьe Ьесamеа statistiсianat thе Mеrсаntilе and Gеnеral InvеstmеntСom. pany in London. Сontrary to lris dеsirеs, Fishеr was kеpt out of \World !Иar I Ьесausеof his poor visiorr. Bеtrд,ееn1915 and l919 hе taught mathеmatiсs

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Fisber and physiсs at a variеty of puЬliс sсhools. |n 1917 hе mаrriеd Ruth Еilееn Gatton Guinnеss, with whom hе would parеnt еight сhildrеn. Onе of Fishеr,s siх daughtеrs,Joan Fishеr Boх, authorеd thе most wеll.known Ьiography of him in 1978. At Rothamstеd Еxpеrimеntal Station' Ьеtwееn I9I9 and 1933, Fishеr madе substantial сontriЬutions to statistiсsand gеnеtiсs.In statistiсs,hе introduсеd thе сonсеpt of likеlihood (Fishеr 1921). Thе likеlihood of a paramеtеr is proportional to thе proЬaЬility of the data and it givеs a funсtion that usually has a singlе maximum valuе, that is, thе maximum likеlihood. And thе nеxt yеar Fishеr introduсеd a nеW сonсеption of stаtistiсs,thе aim of whiсh was thе rеduсtion of data and thе proЬlеmatiс of whiсh Was thе spесifiсation of thе kind of population from whiсh thе data сamе, еstimation, and distriЬution. Soorr thеrеaftеr, Fishеr puЬlishеd StаtistiсаI Мethods for Rеseаrсh Worhers (1925), in whiсh hе artiсulated mеthods for thе dеsign and еvaluation of ехpеrimеnts. Thе 1925 еdition was thе first of many. In gеnеtiсs, Fishеr's first papеr (in 1922| adumЬratеd a mathеmatiсal synthеsisof Dаrwinian natural sеlесtion with thе гесеntly rеdisсovеrеdlaws of Меndеlian hеrеdity. That, and othеr work (е.g.,on thе еvolution of dоminanсе), would сulminatе in The Gепetiсаl Theorу of Nаtиrаl Sеleсtiсlп (1930), onе of thе prinсipal tеxts' along with thosе of J. B. S. Haldanе (1892-1964) and Sеwall Wright (1889_1988),сomplеting thе rесonсiliationof Darwinism and Mendеlism and еstaЬlishing thе fiеld of thеorеtiсal populatiоn gеnеtiсs and its appliсation to еugеniсs.Rеmarkably,Thе Gеnеticаl Theorу of Nаturаl Seleсtkл was diсtatеd Ьy Fishеr to his wifе, Ruth, during thе еvеnings.Thе book was rеvisеd and rеissuеd in 1958. In 1929 Ftsher was еlесtеd to thе Royal Soсiеty. Fishеr lеft Rothamstеd to takе thе Galton Сhair of Еugеniсs at Univеrsity Сollеgе, London, in 1933. Karl Pеarson (1857_19з6) was rеtiring from thе Сhair' whiсh was thеn dividеd into two, so that Ьoth Fishеr and Pеarson's son, Еgon, сould bе appointеd. Fishеr сontrollеd thе gеnеtiсssесtion; Pеarson сontrollеd thе statistiсsSесtion.(Fishеr had turnеd down Pеarson'soffеr of сhiеf statistiсianat Galton LaЬoratoriеs for thе position at Rothamstеd in 791'9.).Whеnhе took thе Galton profеssorshipаt Univеrsity Collеgе' hе was thoroughly mirеd in сontrovеrsy ovеr thе foundаtions of statistiсs with Karl Pеarson and his followеrs. Fishеr's rеvolutionary work in statistiсsсamе at around thе timе that Pеarson's own woгk was showing wеaknеssеs; unfriеndly сompеtition cata|уzed thе сontrovеrsy, and Pеarson would takе ill fееlings toward Fishеr, who had his own ill fееlings toward Pеarson' to his gravе. Thе сontrovеrsy in stаtistiсswith Pеarson would not Ье thе only сontrovеrsy in whiсh Fishеr was involvеd. Bеginning tп 1929, Fishеr and Amеriсan physiologiсal gеnеtiсist Sеwall \Х/rightwould еngagе in an animus-fillеd сontrovеrsy ovеr thе gеnеtiс Ьasis of еvolutionary сhangе that would last until Fishеr's deatЬ ln 7962. In 1935 Fishеr's The Desigп of Ехperimezls appеarеd and, likе StаtistiсаI Мethods for Resеаrсh Workеrs' would Ье ехpandеd and rеissuеd many timеs. Thеsе two works, and Fishеr's Stаtistiсаl Таblеs for Biologiсаl, Аgri-

сulturаl, апd Мedi agriсultural rеsеar fiеld's сonсеptual f lightеd mainly Ьy l good сompany in сomplishmеnts did Royal Soсiеty in 19 1955.In 1943 Fish Ьridgе Univеrsity; i lеgе' СamЬridgе; a ЕlizaЬеth II. Numеl Aftеr a luminous of 72 onJu|у 29, \| Fishеr has Ьeеn dеs volatilе tеmpеr. Fis to his viеws, drovе writings havе bееn morе еffесtivеly сor tion and his gеnius

BIBLIOGRAP

B o x ,J . F . 1 9 7 8 .R . А . Fishеr,R. A. 1921.o frоm а small sar 1922,Оn tЬе Еdiпburgh42:3 1925.Stаtist 1 9 3 0[ 1 9 s 8 York: Dovеr PuЬ 1935.Тhе D. ' Fishеr,R. A., and F. Меdiсаl Rеsеаrс

Fishеs

Thе word fisbes ls a hold. Most pеoplе 1 fsЙ is usеd, but thil thеsе too arе fishеs moving Ьy еithеr (с and/or unpairеd far gеn (and rеlеasеsnl gills'' goеs a long ''

сonsidеrеd fishеs(L living typеs of fishс of known fossil for

Fishеs n 1917 hе marriеd Ruth Еilееn nt еightсhildrеn. Onе of Fishеr's r most Wеll.known Ьiography of еtwееn 1979 and 1933, Fishеr and gеnеtiсs.In statistiсs, hе in) 2 l ) . T h е l i k е l i h t l o do f a p а r а m data and it givеs a funсtion that ;, thе пtaximurn likеlihoоd. And Lсеptionof statistiсs,thе aim of lЬlеmаtiсof whiсЬ was thе spес_ :h thе dаta сamе' еstimatiсln,and hed Stаtistiсаl Мethods for Reated mеthods for thе dеsigrr and W a st h е f i r s to f п r a n y .I n g е n е t i с s ' rathеmatiсalsynthеsis of Darwinvеrеdlaws of Меndеlian hеrеdity. of dorrrinanсе).would сulminatе ion (19ЗО\, onе of thе prinсipal (1892-1964) aпd Sеwall Wright эf Darrvinism and Меndеlism and on gеnеtiсsand its appliсation to l сlf Nаturаl Sеlесtion was diсtatеd gs.Thе Ьook wаs rеvisеd and rеisthе Royal Soсiеty. n Сhaiг of Еtrgеniсsat Univеrsity 857-19з6) was rеtiring from thе ;o that Ьoth Fishеr and Pеarson's trollеd thе gеnеtiсs sесtion; Pеarhad turnеd down Pеarson's offеr for thе position аt Rotharnstеd in ship at Univеrsity Сollеgе' hе was oundations of statistiсs with Karl ionary work in statistiсs сamе at .k wаs showing wеaknеssеs; un.еrsy, and Pеarson would takе ill ll fееlingstowаrd Pеarsorl. to his ,аrsonwоuld not Ье thе only сoninning in 1929,FisЬer and Amеriwould еrrgagеin an animus_fillеd .ionaryсhаngеthat would last unепts appеarеdand, |Ike Stаtistiсаl bе еxpandеd аrrd rеissuеd many istiсаl Tаbles for Biologiсаl, Agri-

сultцrаl, апd Меdiсаl Reseаrсh (with Frank Yatеs, 1938) геvolutionizеd agriсultural rеsеarсh. Fishеr's work in statistiсs was rеvolutionary at thе fiеld's сonсеptual foundations. Мorеover, FishеrЪ work in gеnеtiсs, highlightеd mainly Ьу Thе Geпеticаl Thеorу of Nаturаl Selесtiott' would, with good сompany in Haldanе and Wright, rеvolutionizе Ьiology. Fishеr's aссomplishmеntsdid not go unrесognizеd.Не wаs awardеd thе mеdal of thе Royal Soсiеty in 1938, thе Dагwin mеdal in \948, and thе Сoplеy mеdal in 1955. In 1943 Fishеr was appointed Balfour Profеssor of Gеnеtiсs at СamЬridgе Univеrsity; in 7957 he Ьесаmе prеsidеnt of Gonvillе аnd Caius Сollеgе, CamЬridgе; and in |952 hе was сrеatеd Knight Baсhеlor Ьy Quееn Еlizabеth II. Numеrous othеr honors wеrе Ьеstowеd upon him' Aftеr а luminous сaгееr as statistiсianand Ьiologist, Fishеr diеd at thе аgе of 72 on Ju|у 29, \962, in Adеlaidе, Australia, whеrе hе had rеtirеd iп \9 59 . Fishеr has Ьееn dеsсriЬеdas сharmiпg and Warm among friеnds, Ьut with a volatilе tеmpеr. Fishеr's tеmpеr' сombinеd with an unwavеring сommitmеnt to his viеws, drovе him to hеatеd сontrovеrsiеs with othеr sсiеntists. Fishеr's writings havе Ьееn dеsсriЬеd as diffiсult; muсh of wlrat hе сontriЬutеd was morе еffесtivеlyсonvеyеd Ьy othеrs morе сapaЬlе of simplifying his prеsеntation and his gеnius. вlвLIoGRAPнY -Гbе Boх,J. F. 1978. R, А. Fishеr: Lifе of а Sсieпtist.Nеw Yоrk: \Wilеy. ,.prсlbаЬlе Fishеr,R. ^. |921. on thе еrгсlr''оf a сoеffiсiеnt of сorrеlаrtiоn dеduсеd fronr а small sаmplе.Меrt
-R.А.s.

Fishеs Thе word fishеs is aЬout аs slippеry as thе oгganisms to whiсh it rеfеrs аrе to hold. Мost pеoplе gеnеrallygеt a rathеr similar mеntal imagе whеn thе tеrm fsЙ is usеd, Ьut this rаrеly inсludеs thinking of ееls or еvеn sharks, although thеsеtoo аrе fishеs.Dеfining a fish as ..a wаtеr-dwеlling' ЬaсkЬonеd animal moving by еithеr (or Ьoth) latеral Ьody undulations or osсillаtions of pairеd aпd/orunpairеd fan-likе Ьody appеndagеsсallеd fins and whiсh oЬtains oxygеn (ilnd rеlеasеsnцmеrous dissolvеd wastеs)viа spесializеdstгuсturеsсаllеd gills,' goеs a long Way toward inсluding all organisms that аrе sсiеntifiсally сonsiderеdfishеs(Hеlfmаrrеt al. 79971'PolgЬ еt al. 2005). So divеrsе arе thе living typеs of fishеs,howеvеr, rhаt this dеfinition is not сlеzrrсut. Irrсlusiorr of known fossil forms furthеr strеtсhеs Ьеyond aссuraсy almсlst any attеmpt

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Ьishеs at a сomprеhеnsivеdеfinition. Twо rеasons ассOunt for thе nеar impossiЬility of сlеarly dеfining what sееms at first glanсе to Ье a straightforward noun. First, a numЬеr of distinсt еvolutionary iinеagеs,alЬеit еvidеntiаlly dеrivеd from а сommon anсеstor, survivе today having еnormously divеrgеd in almost all rеspесts through thе influеnсе of naturаl sеlесtion. Sесond, fishеs (thе plural appliеs to morе thаn onе spесiеs,thе singular to individuals of a singlе spесiеsno mattеr how many of thеm) arе thе most Ьiodivеrsеof living ЬaсkЬonеd animals (vеrtеЬratеs).Еxtant (living) fishеs numЬеr no lеss than 27,000 namеd spесiеs,сomprising aЬout 50% of all еxtant vеrtеЬratеs;thеy arе adaptеd to inhaЬit thе nеаrly 71"Ь
nеutral Ьuoyanсy rе rеsponsеs of thе vеr Wаtеr' the sеparatе iсhthyеs havе oftеn adaptation. For еxa than-watеr Ьodiеs, providе Ьuоyanсy. ( poсkеting of thе еs еnсеs dеmonstratе t] variation. Thе еxtant Сhonс typiсal shark is aЬ< gеnomе indiсatеs th vаnсеd Ostеiсhthyе spесiеs in еxistеnсе sizе, Ьut thеy arе gt сеntimеtеr in adult l low thеm to thrivе i: сially in frеshwatеr frеshwatеr haЬitats whilе 58% of livinE еxtеnt) is a morе сс dееd somе frеshwat Thе сiсhlids of Sout сiosе, with litеrally sеvеral gеologiсally sivе parеntal сarе of imprintеd on thеir thеir parеnts in сht rapid gеnеtiс isolati Thе random patt is also aЬundantly < thе vast group knov сatfishеs, lantеrn an almost all сoral rе Tеlеosts first appеa uniquе uniting fеat port of a portion of сlеar adaptivе advа onе linеagе has Ьее dom and сhanсе na

в|BLloGRAP

FishBasе:A GlobаlIr .htm.

Fishеs :ountfor thе nеar impossiЬiltо Ье а straightforwaгdnoun. еs, alЬеit еvidеntially dеrivеd g еnormously divеrgеd in al_ urаl sеlесtion.Sесond, fishes to individuals оf a rе singr.rlar ] thе most Ьiodivеrsе of living g) fishеsnumЬеr no lеss than of al[ е-хtantvеrtеЬrаtеs;thеy lе еarth's surfaсе сovеrеd by 2olotlf tЬе plаnег.ssurГaсе oсаnd еstuагinееnvironmеnts. ttеr'and oftеn in suЬtеrranеаn physiologiсal,and Ьеhavioral to thе lvidеly vari:rЬ1есondiplus an
nеutral Ьuoyanсy rеlativеly еаsiеr to aсhiеvе. Although dеmonstrating similar геsponsеsof thе vеrtеЬrаtе Ьody to thе natural sеlесtion dеmands of living in Watеr' thе sеparatе еvolutionary сladеs of thе Chondriсhthyеs and ostеiсhthyеs havе oftеn usеd vеry diffеrеnt mесhanisms to aсhiеvе a сommon аdaptation' For еxaпrplе' to ovеrсomе thе еffесt of gravttу on thеir dеnsеrthan-wаtеr Ьodiеs, сhondriсhthyеs havе еvolvеd laгgе' oil.riсh livеrs that providе Ьuoyanсy. Ostеiсhthyеs havе modifiеd an aцxiliary геspiratory outpoсkеting of thе еsophagus into a gas-fillеd Ьuoyanсy Ьladdеr. Suсh diffеrеnсеsdеmonstratе thе random naturе of adaptation Ьasеd on сhanсе gеnomе variation. Thе еxtant Сhondriсhthyеs аrе flеsh еatеrs and gеnеrally largе organisms. A typiсаl shark is aЬout 2 mеtеrs long. Еvidеnсе from analysis of thе shаrk gеnomе indiсatеs that thеy hаvе еvolvеd at a muсh slowеr ratе than havе ad. vanсеd Osteiсhthyеs. This may aссount for thе rеlativеly small numЬеr of spесiеsin ехistеnсе today. Living ostеiсhthyеs arе highly variaЬlе in diеt and sizе, Ьut thеy arе gеnеrally sшallеr than sharks' with somе Ьеing lеss than a сеntimеtеrin adцlt maхimum lеngth. Thеir diеtary Ьrеadth and small sizе allow thеm to thrivе in many morе haЬitats than any othеr сladе of fishеs, еspесially in fгеshwatеr еnvironmеnts. Forty.onе pеrсеnt of all fish spесiеs livе in frеshwatеrhaЬitats, whiсh arе highly dividеd and isolatеd onе from anothеr' whilе 58% of living spесiеs oссur in thе sеa, whiсh (in spitе of its еnormous ехtеnt) is а morе сontinuous hаЬitat than thе еpiсolrtinеntаl fгеshwаtеrs. Indееd somе frеshwatеr Ьony fishеs show astoundingly high ratеs of еvolцtion. Thе сiсhlids of South Amеriсa, Afriсa, and Sоuthеrn India arе еspесially spесiosе, with litеrally hundrеds of spесiеs having еvolvеd in situ in еaсh of thе sеvеralgеologiсally young Afriсan Rift Vallеy lakеs. Bесausе thеy havе еxtеnsivе parеrrtalсarе of еggs and young' сiсhlid offspring сan Ьесomе Ьеhaviorally imprintеd on thеir Parеnts аnd show a prеfеrеnсе for individцals similar to thеir parеnts in сhoosing thеir own matеs (assoгtativе mating), rеsulting in rapid gеrrеtiсisolation and sеlесtion lеading to nеw spесiеs. Thе random pattеrn of еvolution without dirесtion or сlеar sеlесtivеvaluеs is also aЬundantly dеmonstratеd Ьy fishеs. Almost аll ostеiсhthyеs Ьеlong to thе vast group known as Tеlеosts, inсluding ееls, hеrrings, salmons, minnows, сatfishеs,lаntеrn and othеr dееp-sеafishеs,сods, anglеrfishеs,bassеs,pегсhеs, almost аll сoral rееf fishеs' and so on. Thеrе arе 25,000 or morе spесiеs. Tеlеostsfirst appеaгеd аЬоr.rt200 million yеars ago in thе mid-Tгiassiс. Thеir uniquе uniting fеaturе is а struсturally rаthеr minoг shift in thе intеrnal support of a portion of thе tail (сaudal) fin that doеs nor appеar to givе thеm any сlеar adaptivе advantagе ovег othеr сontеmporary fishеs. Nеvеrthеlеss, this onе linе:rgеhas Ьееn thе gеnеsisof most fishеsliving today, illustrating thе random and сhanсе naturе of еvolution.

B|вLIoGRAPHY FishBasе:A GloЬal In{ormationSystеmon Fishеs.http://www.fishЬasе.org/homе .htm.

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Fitсh Hеlfman, G. s., B. B. Collеttе,and D. Е. Faсеy. 1997.Tbе Diuеrsitуof FisЬеs, Маldеn, МA: Blaсkwеll Sсiеnсе. Maisеy, I. G. 1996.DisсouеriпgFossilFishes.Nеw York: Hеnry Holt and Сompany. Pough'F. H., С. M. Janis,and J. B. Неisеr.2О05.Vеrtеbrаte Lifе.7tЬ сd.PartsI and -r.B.Н. П, 1-156.Uppеr SaddlеRivеr,NJ: PrеntiсеНall.

Fitсh,

.Waltеr rv[.(b. 1929)

Philosophеr Isaiah Bеrlin (1953) сharaсtеrizеdintеllесtualеndеavor as Ьеing сonduсtеd Ьy еithеr hеdgеhogs or foхеs. Hеdgеhogs spend thеir livеs foсusing intеntly on a singlе сohеrеnt issuе, whilе foxеs сonsidеr numеrous' at timеs еvеn unrеlаtеd' proЬlеms. For thе most part' this diсhotomy holds up wеll for sсiеntifiс inquiry, Ьut thеrе arе notaЬlе еxсеptions who upsеt thе .Walter rulе. М. Fitсh, who managеd to makе lasting сontriЬutions to thе fiеld of molесular еvolution, is onе suсh ехсеption. In partiсulaг, Fitсh's сarееr has Ьееn distinguishеd Ьy groundЬrеaking advanсеs in mеthodology, thе kind of еffort that rеquirеs thе digging aЬility of а hеdgеhog, as wеll as fundamеntal сonсеptual аdvanсеs aсross a rangе of topiсs, aсhiеvеmеnts that nесеssitatе thе mеntal agility of a foх. Trainеd as a Ьioсhеmist, Fitсh has spеnt thе Ьеttеr part of his сarееr at thе Univеrsity of !Иisсonsin and latеr at thе Univеrsity of California at lrvinе. !7hen hе Ьеgan his сomparativе rеsеarсh on protеin sеquеnсеs' thе notion of molесular еvolution was littlе morе than a fantasy;hе is as muсh rеsponsiЬlе as anyonе for thе еmеrgеnсе and dеvеlopmеnt of this nаsсеnt rеsеarсh program into a major, lеgitimatе, and distinсt disсiplinе at thе nеxus of еvolutionary and molесular Ьiology. Togеthеr with Мasatoshi Nеi, anothеr luminary of molесular еvolution, Fitсh foundеd thе Soсiеty for Molесular Bi. ology and Еvolution and its journal, Мoleсulаr Bhlogу апd Еuolution, whiсh rеmains thе prеmiеr journal in thе fiеld and is onе of thе highеstranking journals in thе еvolutionary Ьiology fiеld. Thе сontriЬutions that Fitсh has madе arе numеrous' so a mеrе samplе of what Fitсh has givеn to molесular еvolution is prеsеntеd Ьy fосusing on his work in thrее distinсt arеas:mеthods' сonсеpts' and appliсаtions. A сrowning aсhiеvеmеnt of molесular еvolution is thе usе of phylogеnеtiс mеthods to rесonstruсt thе еvolutionary histoгiеs of gеnеs, protеins, and, Ьy ехtеnsion' spесiеs. Whеn rеlatеd protеin sеquеnсes Ьеgan to aссumulatе in thе latе 1950s and еаrly 1960s, thеrе wеrе no mеthods availaЬlе to ana|уze thеm from an еvolutionary stаndpoint. Numеriсal taxonomy mеthods had only just Ьееn formalizеd into algorithms, Ьut thеsе approaсhеs сould not Ье rеadily appliеd to sequеnсе data. \Working with Еmanuеl Мargoliash' Fitсh publishеd a sеminal papеr in 1967 tЬat rеportеd thе first distanсе-Ьasеd mеthod for phylogеnеtiс rесonstruсtion of protеin sеquеnсеs.Distanсеs wеrе сomputеd as thе proportion of amino aсid diffеrеnсеs Ьеtwееn all pairs of sеquеnсеs undеr сonsidеration. Thе Fitсh'Margoliash mеthod amountеd to a сlеvеr implеmеntation of thе lеast squarеs statistiсal prinсiplе, whеrеЬy a phylogеny was rесonstruсtеdsuсh that thе distanсеs along thе Ьranсhes of

thе trее showеd thе tanсеs. A сritiсal fеa fог thе faсt that grе \Х/hilе thе algorithm fadеd from usе, dist proaсh for rесonstru lеast squаrеs has rеr Margoliash mеthod i thеir papеr, basеd on givеn what wе know onе of thе most iп twееn so-сallеd сlrthс usеd thеm to distingu spесiation еvеnts (or (paralogs).This disti studiеs Ьut also for tL 1990s, thе orthologtool for invеstigato quеnсеd gеnomеs.T| Samе' or vеry simila havе divеrgеd in funс сomparisons сan oЬs сonflation of ortholo1 сomparison approaс proсеss Ьy disсrimin (2000) allow for mor Еvoiutionaгy Ьiolo lutionists arе prеsеn past еvеnts Ьasеd sol sеqrrеnсеsof ехtant с suсh as thе fossils uti Ьy historians' moiесu of tools that providе adеpt' howеvеr, aЬo еvеnts. In an audaсiс to dеfy this trеnd Ьy fort did not rеprеsеn influеnza virus, and 1 еpidеmiсs. Suсh a pr fluеnza strains to usе on a phylogеnetiсap nomiс sеquеnсеsto t fеstеd itsеlf with thе that rеprеsеntеdthе natеd еpidеmiсs frorг sеquеnсе'Fitсh and l

Fitсb 7, Тhе Diuеrsitус-lfFishеs. York:HеnryHolt and ,еrtеbrаtе Life.7th еd. Parts I and

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intеllесtualеndеavor as Ьеing ;еhogs spеnd thеir livеs foсus: foxеs соnstсiеrnumеrous' at part, this diсhotomy holds up LЬlеехсеptions who upsеt thе lе lasting сontriЬutions to thе ption. In partiсular, Fitсh's сa; advanсеsin mеthodology, thе of a hеdgеhog, as wеll as funlf topiсs,aсhiеvеmеntsthat nе: Ьеttеr part of his сarееr at thе vеrsity of California аt lrvinе. lrotеinsеquеnсеs,thе notion of ltasy;hе is as muсh rеsponsiЬlе rt of this nasсеnt rеsеarсh proisсiplinе at thе nеxus of еvoluwith Masatoshi Nеi, anothеr эd thе Soсiеty for Molесular Bi'сulаr Biologу апd Еuolцtion, еld and is onе of thе highеsty fiеld. Thе сontriЬutions that lplе of what Fitсh has givеn to o n h i s w o r k i n t h г е еd i s t i n с t a r ution is thе usе of phylogеnеtiс lriеs of gеnеs'protеins, and, Ьy uеnсеs bеgan to aссumulatе in Lomеthods availaЬlе to ana\уze nеriсaltaХonomy mеthods had t thеsеapproaсhеsсould not bе uith Еmanuеl Мargoliash, Fitсh portеd thе first distanсе-Ьasеd 'otеinsеquеnсеs.Distanсеs wеrе ffеrеnсеsЬеtwееnall pairs of sегgoliash mеthod amountеd to a statistiсalprinсiplе, whеrеby a distanсеsalong thе Ьranсhеs of

thе trее showеd thе lеast diffеrеnсе with thе pairwisе protеin sеquеnсе distanсеs.A сritiсal fеaturе of thе mеthod was a wеighting sсhеmе that allowеd for thе faсt that grеatеr distanсеs wеrе likеly to Ье rеlativеly lеss rеliablе. !Иhilе thе algorithmiс implеmеntation of thе Fitсh-Margoliash mеthod has fadеd from usе, distanсе mеthods arе сurrеntly thе most widеly usеd approaсh for rесonstruсtingphylogеniеs,and thе gеnеral сritеrion of wеightеd lеast squarеs has rеmainеd viaЬlе. Thе utility and rеliaЬility of thе FitсhMargoliash mеthod is undеrsсorеd Ьy thе eukaryotiс phylogеny rеportеd in thеir papеr, Ьasеd on сytoсhromе с sеquеnсеs'whiсh is rеmarkaЬly aссuratе givеn what wе know now. onе of thе most important сonсеpts in gеnе еvolution is thе distinсtion Ьеtwееnso-саllеdorthologs and pаralogs.Fitсh сoinеd thеsеtеrms in 197О and usеdthеm to distinguish Ьеtwееngеnеsthat sharе a сommon anсеstor duе to spесiationеvеnts (ortholоgs) and gеnеs that divеrgеd via gеnе dupliсation (paralogs).This distinсtion is rеlеvant not only for Ьasiс molесular еvolution studiеsЬut also for thе undеrstandingоf protеin funсtion. Indееd,Ьy thе latе 1990s,thе ortholog-paralog diсhotomy Ьесamе an indispеnsaЬlесonсеptual tool for invеstigators trying to annotаtе thе pгoduсts of сomplеtеly sеquеnсеdgеnomеs.This is Ьесausеorthologs tеnd to еnсodе protеins with thе samе' or vеry similar, funсtions, whilе paralogs oftеn еnсodе protеins that havе divеrgеd in funсtion. Information transfеr Ьasеd only on naivе sеquеnсе сomparisonsсan oЬsсurе thеsеfaсts and lеad to misannotationsЬasеd on thе сonflation of orthologous and paralogous sеquеnсеs.Morе nuanсеd sеquеnсе сomparison approaсhеs that еmЬraсе Fitсh's artiсulation of thе еvolutionaгy proсеssЬy disсriminating Ьеtwееnortholоgous and pаralogous rеlationships (2000)allow for morе rеliaЬlе and usеful annotatlons. Еvolutionary Ьiology is an ехpliсitly historiсal sсiеnсе,and molесular еvo. lutionists arе prеsеntеd with thе uniquе сhallеngе of infеrring thе naturе of past еvеntsЬasеd solеly on сontеmporanеousdata' namеly gеnе and protеin sеquеnсеsof ехtant orgаnisms. Dеspitе thе laсk of aссеss to historiсal data, suсh as thе fossils utilizеd Ьy palеontologistsor thе anсiеnt tехts dесiphеrеd Ьy historians,molесular еvolutionistshavе suссеssfullydеvеlopеd an arsеnal of tools that providе a window to thе past. Еvolutiоnary sсiеnсе is far lеss adеpt, howеvеr, aЬout making prеdiсtions сonсеrning thе firtrrrе сoursе of еvеnts.In an audaсious sеriеs of studiеs,Fitсh and his сollеaguеsattеmptеd to dеfy this trеnd Ьy aсtually prеdiсting futurе еvolutionary еvеnts. Thеir еffort did not rеprеsеnta mеrе aсadеmiс еxеrсisе.Thе oЬjесt of study was thе influеnzavirus, and thе idеa was to try and prеdiсt thе сoursе of fцturе flu еpidеmiсs.Suсh a prеdiсtion would providе a Ьasis for sеlесtingamоng inflllenza strаins to usе in thе produсtion of a vaссinе. To do this' Fitсh rеliеd on a phylogеnеtiсapproaсh сomparing thе rеlationship among flu strain gеnomiс sеquеnсеsto thе datеs when thеy wеrе сollесtеd. A сlеar trеnd mаnifеstеditsеlf with thе influеnza phylogеny showing a suссеssfultrunk linеagе thаt rеprеsеntеd thе еvolutiсlnary history of thе influеnza strains that dominatеd еpidеmiсs from onе yеаr to thе nеХt. Foсusing on individual sitеs in thе sеquеnсе'Fitсh and his сollеaguеs(Fitсh et a|. 19971Bush еt aL. 1999) were

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586 Ford aЬlе to idеntify spесifiс variablе positions in thе influеnzа sеquеnсе that сould bе usеd to hеlp prеdiсt thosе strains that will сausе futurе еpidеmiсs. This Ьold departurе from thе еluсidation of past rvеnts)thе status quo for almost аll of еvolutionary Ьiology, to thе prеdiсtion of futurе еvolr.ttionаry traforward stands tеstаmеnt arrd prеsсiеn1се hаs аs a to thinking that iесtoriеs lй/altеr maгkеd Fitсh as a trulv еxсеDtionalmolесular еvolutiollisr' BlвLIoGRAPHY Bегlin,I. 1953.Thе Неtlgеhogапd tbе Лoх.Londоn:Wеidеnfеldаnd Niсolson. 'W. Bush,R. М.' с. A. Bеndеr,K. SuЬЬarao,N. J. Сoх, llr-rd М. Fitсh' 1999. influеnzaА. Sсiеnсе286: 792|-1925, Prеdiсtingсhееvolutionof hunrаr-r Fitсh, W. \4. 197О.Distinguishinghomologousfrom analоgousprotеins.Sуstеmаtiс Z o o l o g у1 9 : 9 9 - 1 1 3 . 1'971,a. Rate оf сhangеof сonсomitantlyvariаblесodons.lourпаI of Мolесulаr Еuolцtiolt |: 84-96. 1971ь.Toward dеfiningthе сoursеof еvolrrtion:Мinimun-rс:lrаrngе for a spесifiсtrееtopology.Sуstеmаtiс Zoologу 2О:406416' 2000. Homology:A pеrsonalviеw on somеof thе proЬlеms.Trепdsiп Gепеtiсs16 227_2з1. Fitсh,W. M., R. M. Buslr.С. A. Bеndеr,and N. J. Coх. |997.Long tеrnrtrеndsin o|.tbе thе еvolutionof Н(З) HA1 humanirrfluеnza typеA. Prсlсееdiпgs Nаtionаl Aсаdепryof SсieпсesL]SА 94: 7772,-7718. Fitсh,W. \4., and Е. Margoliash. 1967.Соnstruсtionof phylogеnеtiс trееs.Sсieпсе \55 279-284. Fitсh, !7. М., and Е. N1аrkоwitz.1970.An improvеdmеthodfor dеtern-rining сodon variabilityin а gеtrеаnd its appliс:rtion to thе rаtеof fiхationof mut:rtiоns in е r ' o l u t i o n .B i o с h с п t i , . dG е п с t i с s4 : > 7 9 - 5 9 3 .

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Ford, Еdmund Brisсo (1901-1988) Е. B. Ford, usually сallеd Hеnгy Ьy lris сollеaЕ.uеsаnd friеnds, is Ьеst known as thе сhiеf proponеnt of thе rеsеarсhprogram known as есologiсal gеnеtiсs. Intеndеd to throw light on thе rolе of gеnеtiс divеrsity in thе adaptation of organisms to thеir еnvironmеnts, eсologiсal gеnеtiсs Ьеgins with oЬsеrva. tions of variation in nаtural populations. Brееding studiеsthеn dеtеrminеthе mannеr of inhеritanсе of thе diffеrеnt variаtions. Cоmparativе analysеs of diffеrеnt haЬitats and сorrеlations of еnvironmеntal and gепеtiс variaЬlеs lеad to hypothеsеsаЬout thе rolе of variation in еvolutionary adaptation. Finally' ехpеrimеntal manipulation of еnvironmеntal variaЬlеs rеsults in thе сonfirmation or rеjесtion of thе hypothеsеs.Ford's rеsеarсhphilosophy is sеt out in lris sеminal Ьook, Есolс-lgiсаlGenеtiсs. Ford spеnt his еrrtiresсiеntifiс сarееr at Oхford Univеrsity' Hе matriсulatеd as an undеrgraduatеin 192О, reсeivinga BA in zоology iп |924 and a BSс in \927. tle wаs appointеd Dеpartmеntal Dеmonstrator in Zoo|ogу (1927|, thеn Univеrsity Dеmonstrator (1929) and Lесturеr at Univеrsity сol. lеgе (1933). Iп 19З9, hе Ьесaпrе Rеadеr in Gеnеtiсs, thе first еxpliсit аppointmеnt in that suЬjесtin oхford. Hе еstaЬlishеdthе Gеnеtiс l-aЬoratoriеs in 1951 and rесеivеd an appointmеnt as Profеssor of Есologiсal Gеnеtiсs in

1.96З, a post hе hеll of All Souls Сollеgt сеivеd its Darwin Nz Ford сamе to thе еst in thе Lеpidоptе thеr of a populatio: Their pеrsonal оЬsе сality rесords going thе papеr puЬlishеd aЬility of thе popult lесtion, whiсh allolr hе maintainеd his i on thеsе animals ir Ьеstsеllеrfor thе sеr Ford's earliеstwс lеy of a gеnе that af. cheureuхi. Thеy sh gеnе' but also оn t} growth. Although I gеnеs' tЬe Gаmmаr Ford is pеrhaps was thе first to offс parеd for Julian Ht Ford's ЕсologiсаI С rеnсе toBеthеr in th spесiеs in suсh pro1 rесurrеnt mutatlon whiсh onе morph i anсеd polymorphis nеtiс polymorphisr among loсi сontrit ..su what hе сallеd phеnotypеs' Batеsi amplеs of supеrgеn Although not gi R. A. Fishеr in thе ] thе Sсarlеt Тigеr m Ford was aЬlе to tr yеarly сеnsusеs.Fi quеnсy wеrе too g1 сontеntion at thаt of еffесtivеpopula that thе original an Ford was also in populations. For п thе hindwings of ,V

Ford in thе influеnza sеquеnсе that rаt will сausе futltrе еpidеmiсs. ast еvеnts' thе status quo for alсtion o{ futurе еvolutionary trarinking and prеsсiеnсе that has rolесulаr еvolutiоnist.

on: Wеidеnfеldаnd Niсolson. .W. 'x, and М. Fitсh. 1999. \. Sсiепcе286: 1921-7925. .om anаlogоusprotеins. Sуstеmаtiс v:rriаblесodons.Jourпаl of эlution:Мinimum сhangе for a ):406416. .Гreпds in Gemе of thе proЬlеms. | . С o х . 1 9 9 7 . L o n g t е r m t r е n d si n t,vpеA. Proсееdiпgs сlf thе 7.-7718. :tiоrrof phylogеnеtiс treеs. Sсienсе for dеtеrmining сodon эvеd r-rrетhod е rаtеtlf fiхlrion tlf rnut.rtionsin

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)a8uеsand friеnds, is Ьеst known 21In known as есologiсal gеnеtiсs. ltiс divеrsity in thе adaptation of al gеnеtiсsЬеgins with oЬsеrvaееdingstudiеsthеn dеtеrminе thе iations.Сomparativе analysеs of rоnmеntal and gеnеtiс variaЬlеs ln in еvolutionaryadaptation. Fi)nmеntal variaЬlеs rеsults in thе . Ford's rеsеarсhphilosophy is sеt o х f o r d U n i v е r s i t 1. H е m а t r i с u rg a BA in zoology iп |924 and a rеntаl Dеmonstrator in Zoo|ogу 9) and Lесturеr at Univеrsity Сolin Gеnеtiсs, thе first ехpliсit ap. aЬlishеdthе Gеnеtiс LaL.loratoriеs rofеssorof Есoloяiсal Gеnеtiсs in

196З, a post hе hеld until his rеtirепrеntin \969. }-ord was еlесrеda Fеllow of All Souls Сollеgе in 1958. Hе was a Реilow of thе Royаl Soсiеty аnd rесeivеdits Darwin Меdal tn 1954. Ford сamе to thе study of gеnеtiсs and еvolution through his lifеlong intеrеst in thе Lеpidoptеra. Bеforе attеnding Oхford, hе Ьеgan a study with his fathеr of a population of Меlitаеа (Еиphуdrаs) аuriпiа, thе Marsh Fгitillary. Thеiг pеrsonal oЬsеrvationsеmЬraсеd thе yеаrs from 1917 to 1935, and loсаlity rесords going Ьасk to 1881 mаke this an unusually lеngthy study. In thе papеr puЬlislrеdwith his fathеr in 1930, Ford attriЬutеdthе unusual variability of thе population during pеriods of aЬundanсе to thе rеlaxation of sеlесtion,whiсh allowеd suЬoptimal phеnotypеsto survivе.Throughout his lifе hе maintainеd his irrtеrеstin moths and Ьцttеrfliеs,prrЬlishingtwo volumеs on thеsе animals in Сoliins's Nеw Naturalist sеriеs. Ilts Bltttеrfljes wаs a Ьеstsеllеrfor thе sеriеs. Ford's еarliеstwork at Oхford was a сollaЬorativе study with Julian Huхlеy of a genе that affесtеd thе ratе of darkеning of tlrе еyе сolor in Gаmmаrlls chеureuхi. Thеy showеd that thе гirtе dеpеnds not only on thе Mеndеlian gеnе,[.lutаlso on thе sizе of thе еyе, thе tеmpеraturе'and thе ratе of Ьodily growth. Although not thе first to аttгiЬutе еvolr'rtionaryimportanсе to ratе gеnеs'thе Gаmmаrus studiеsprovidеd an important еarly ехamplе. Ford is pеrhaps Ьеst known fоr his woгk on gеnеtiс polymorphism. Hе Was thе first to offer a сritiсal dеfinition of thе phеnomеnon in a papеr prеpaгеd for Julian Huxlеу,s The Nеtu S1'5ngmаtiсs(1940), rеfinеd as follows in FordЪ,Есologiсаl Gепеtiсs (|964,84). ..Gеnеtiсpolymorphisrrris thе oссurrеnсе togеthеr in thе samе loсality of two or morе disсontinuous forms of a spесiеsin suсh proportions that thе rarеst of thепr сannot Ье maintainеd Ьy rесurrеnt mшtation.'' Hе distinguishеd Ьеtwееn transiеnt polymorphism, in whiсh onе morpЬ is in thе proсеss of rеplaсing anothеr, and staЬlе or Ьalаnсеd polymorphism, maintainеd by staЬilizing sеlесtion.Hе notеd thL1tgеnеtiс polymorphism oftеn irrvolvеd largе phеnotypiс еffесts, сlosе linkagе among loсi сontriЬuting to thosе еffесts, and strong sеlесtion, lеading to ..supеrgеnеs.'' what hе сallеd Hе intеrprеtеdthе ABo Ьlood grouрs' Rhеsus phеnotypеs, Batеsian mimiсry in Ьuttеrfliеs, and hеtеrostyly in plants as еxamplеs of supеrgеnеs'a position Ьornе out Ьy suЬsеquеntrеsеarсh. Although not givеn to mathеmatiсal nrodеling, Ford сollаЬorаtеd with R. A. Fishеr tn thе |947 study of а сolor polymorphismin Pапахiа dсlmiпulа, thе Sсarlеt Tigеr moth. Sinсе hеtеrozygotеs at this loсus arе distinguishaЬlе, Ford was aЬlе to traсk gеnе frеquеnсy and populаtion sizе in a long sеriеsof yеarly сеnsusеs.Fishеr,s analysis еstaЬlishеd that thе сhangеs in gеnе frе. quеnсy wеrе too gгеаt to Ье Ьrought aЬout Ьy gеr.rеtiс drift аlonе, a point of сontеntion at that timе. Although сhallеngеd Ьy Sеwall \Иright on thе Ьasis of еffесtivеpopulation sizеs,suЬsеquentwork on this сolony has еstaЬlishеd t h а t t h е o r i g i n a l a n a l y s i sW а s с o r г е с t . Ford was also intеrеstеdin thе еffесtsof polygеnеs on variation in natural populations' For many yеars hе studiеd variation in thе pattегns of spots on thе hindwings of Мапiсllа ;jиrtiпа,thе Mеadow Brown Ьuttеrfly. Tlrе pattеrns

587

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Fсlrm and Funсtiсlгr wеrе геmark:rblyсonstant ovеr widе arеas of Еuropе, Ьut thеy shoц,еdgrеat сhzrngеsovеr slight distarrсеsin sor.rthwеstЕngland arrd thе Islеs of Sсillv' Spot pattеrns on thе lаrgе islands tеndеd tсl Ье similar, whilе tlrosе from smallеr islands diffеrеd rаdiсally. Ford attriЬutеd tl"rесonstanсy сlf pattеrn ovеr timе to staЬilizing sсlесtion and thе diffеrеnсе bеtwееn largе .rnd small islаnds to thе еffесt of avеrirgingovеr divеrsе haЬitаts orr thе largе islands. In addition to his gеnеtiс woгk' Ford madе сorrtriЬutionsirr sеvеral othеr fiеlds. Не puЬlishеd on thе сhеmistry of Ьuttеrfly pigllrеnts'on thе arсhaеology of southwеst Еnglаnd' and on thе сontеnts of сhurсhеs in thе Oхford distriсt. Pеrhaps Forсl'sgrеaсеstirrrрilсton thе str'rdyof vari:lti
Forrn аnd Function (Еdward s. Russеll) Еdward S' Rr"rssеll's Forп апd Ft.mсtiсlпis а uniqr.rеlуr,aluаЬlеrеsollrсе in thе history of аr-rimаlmorphology. It is a livеIy еxploratiоn of thе most imporrant morphologiсаl thесlristsfгom thе ninеtееnththrough thе еarly twеntiеth сеnturiеs. How сould a rеport on long-dеad moгphologists Ье livеly? Thе livеli. llеss сomеs frorr-rthе faсt thаr Russеll organizеsthе thеoristsaround а сеntral dеЬаtе thi1tpеrsistеdthroughout thе nilrеtееnthсеlltuгy and pеrsistsеvеn today. Thе dеЬatе is in thе titlе. Form аnd Fuпсtioи сould just as wеll hаvе Ьееn titlеd Рorm uеrsus Fuпсtioп. To put thе mattеr simply, whiсh сamе first, form or funсtion? Why do Ьodiеs of anirrralshavе thе ftlrms thеy d
thеn thе fr-rrrсtionsthаt ' of ftlrm. Russеll rеfеrrс no s i t i r T h е p r t l - { u n с г i r lp Р r i o r г o С h а г | е sD e r w i r l natural tlrеologians.Aft impсlrtanсеof naturаl st in thе i830 dеЬatе Ьеt Hilairе (Сolеman 1964 forms of аnimal Ьodiеs h а d t о b с s е r v е d ,t h е i r tlrat animirls slrarеdаbst D a r w i l r r е p t l r r е dO l l t l ) i on thе siJе of |.unсtion funсtion-was thе сaus(

It is gеnеrall1,aсkn
Latеr-ninеtееnth-сеntu douЬtеd thе powеr rlf r iormal, oг somеtilllеsL Ь o d i е so f a n i m а | s( s е еН Form tlпd Fuпсtirlп t tехts and rеpr:oduсti< of Rr trеatisеs.((iсl1.liеs rrinеtееnth сеntury lrlrr. nals Ьy lirtеr historians t е n t i O ne t i t s p u Ь l i с . r аnd sorn morph
Еtlгm and Futrсtiоn .t89 Lrоpr'Ьut thеy showеd grеat ,l.rndаnd tlrе Islеs of Sсilly. ,е similar, whilе thosе from еd thе сonstenсy of pattеrn nсе Ьеtwееnlargе Lrnd small Ьitatson thе largе islands. ontriЬutiсlnsin sеvеral othеr |y рigmеnts,on thе arсhаеols оf сhurсhеs in thе oxford f variationin naturаl populas with his studеnts and сolе p p a r d ,С r ' ' r i l A . С l a г k е , A . J . ,inсolrrP. Browеr, Jt>hnR. G. d was pеrhapstoo irrсlinеd to a r rС l а r k е( I 9 9 5 , 1 6 2 ) m a k е s ,,stt||Еcologiсаl Geпеюir, thе hеld, still it is thе сlеaгеst i o r l i s rv. i е w ,а n d s t i l l i t i s а j o у

саl Mеtпоirs сlf FеIloш's of thе 4. Еvolutionarystudiеs on Iеrеtlit1,1'9 47 |-488. g r l l еi n n з т t t г l lс o t l t l i т i t l n isl l а |it1,1: 11З_174' Сhарrllan аnd Наil. -onr.1tln:

-1.til.

еll) iquеlyvaluaЬlеrеsourсе in tlrе loraтionof thе most irnportarrt lrough thе еarly twеntiеth сеnlhologistsЬе livеly? Thе livеlis tlrеthеoгistsaround a сеntral h сеnturyand pеrsistsеvеn toпсtitlп сoa|d jr-lstas wеll havе -rattеrsimplу, whiсh сamе first, tavеthе forrnsthеy do? Do thе r sеrvеd?If so, funсtiorralism is t. or arе orgenismiсforms or еrаtingproсеssеs?lf thе lattеr,

thеn tlrе funсtions that Ьody рarts sеrvе arе thе Ьy.produсts' llot thе сausеs ..puге morphology.'' of fоrпr. Rrrssеll rеfеrrеd to thе prсl-fgiсalplatеs froln thе ninеtееnthсеntury havе оftеn Ьееn passеd сlff as геproduсtions of thе origi. nals Ьy latеr lristoriаnsand biologists.)Ironiсallv, thе Ьook rесеivеd littlе attеntion at its puЬliсаtion in 1916. |t Ьеgan tсl Ье takеn morе sеriously Ьy morphologists аnd sсlmееvtllutionary thеorists around 797О.The rеason' a sесond irtllrv, was that thе study of mtrrphоlogу \,\,еntthfoug'h a dry spеil during thе еarly twеntiеth сеntury. Thе modегn synthеtiсthеoгy of еvolution (sееthе mairl еssаy ..Thе Hist
590

Form and Funсtion in this volumе), whiсh was inauguratеd in thе 19З0s and wеll еstaЬlishеdЬy 1950, saw littlе importanсе in traditional morphologiсal studiеs.Нowevеr, a growing minority of еvolutionaгy thеorists' somе of thеm сritiсs of thе synthetiс thеory' wеrе rесonsidегing thе impоrtanсе of morphology during thе 1970s. Onе of thеsе,Gеorgе V. Laudеr, a nеw assistantpгofеssorat thе Uni-l vеrsity of Сhiсago in 981' lеarnеd that thе Univеrsity of Сhiсago Prеss was rеprinting historiсally important sсiеntifiс tехts. He nоminatеd Form апd Fuпсtioп and wrotе a usеful introduсtion. Laudеr disсussеdwhy morphology had so littlе rеlеvanсе to thе synthеtiс thеory of еvolution' Ьut hе rеportеd that morphologists wеrе onсе again Ьеginning to сonsidеr thе ninеtееnthсеntury topiсs of struсtural pаttеrns and prinсiplеs of organismiс dеsign. So Russеll,s 1916 Ьook was rеprintеd Ьесausеof thе rеbirth of intеrеstin morphology around 1980. Laudеr and othеr twеntiеth-сеnturymorphоlogists drеw insights from Russеll's history that wеrе rеlеvant to сontеmporary dеЬatеs in еvolutionary thеory (Laudеr 1996; Amundson and Laudеr |994). Russеll himsеlf favorеd funсtionalism ovеr purе morphology, Ьut his book prеsеntеdthе purе morphologists in a sympathеtiс light. Rесognition of thе virtuеs of his Ьook Was not limitеd to morphologists' howеvеr. Еrnst Mayr' arсhitесt of thе synthеtiс thеory of еvolution and a funсtionalist to thе сorе' сommеntеd on Form апd Fuпсtiсlп: ,,TЬerе is proЬably no othеr Ьrаnсh of Ьiology for whiсh wе havе as supеrЬ a history as fоr morphology: Russеll (1916) is unsurpassеdto this dаy, rеmarkaЬ1еfоr its frеsh analysis of thе prim a r y s o u r с е s ' '( М a y r 1 9 8 2 , 8 7 9 n | 5 ) . в|BLloGRAPHY Amundson,R., аnd G. V. Lаudеr.1994.Funсtiсlnwithoutpurposе:Thе usеsof сausalrolе funсtionin еvolutionaryЬiology.Biologу апd Phibsophу 9: 44з469. Appеl' T. А. |987. The Сuuiеr-GеoffroуDеbаtе:FrепсhBiologу iп thе Dесаdes bеforeDаrшiи. Nеw York: Oxford UnivеrsityPrеss. .w.1964' Colеmаn' GеorgesСuuiеr' Zoologist:A Studу iп the Histсlrусlf Еuolution Thеorу.СamЬridgе,МA: HатvаrdUnivеrsityPrеss. Darwin, с. 1859.Оn thе Оrigiп of Spесles.London:John Murrаy. Lаudеr'G.У. 1996.Thе argumеntfrom dеsign.ln M. R. Rosе аnd G. V. Laudеr, еds.,Аdаptаtiсlп,55-91. San Diеgo'СA: AсadеmiсPrеss. Mayr, Е. 1982. The Groшth сlf Biohgiсаl Thсlught.CаmЬгidgе,МA: Нarvard UnivеrsityPrеss. Riсhards,R. J. 2008. Thе Trаgiс Sепsеof Lifе: Еrпst Hаесkеlапd thе Strиgglеouеr ЕuсllиtioпаrуThought.Сhiсago:Univеrsityof Сhiсago Prеss. Rusе, M. 1996. Мoпаd to Мап: Tbе Сспсеpt of Prсlgrеssiп ЕuolutioпаrуBiologу. Сambridgе,MA: Harvаrd UnivеrsityPrеss. 2ОО3.Dаrtuiп апd Dеsigп:Doеs ЕuolutitlпНаue а Purpose?СamЬridgе, МA: Harvard UnivеrsitуPrеss. Russеll,Е. S. 19l 6 [1982|.Form апd Fuпсtioп.London:John Мurray. Rеprint, Сhiсago: Univеrsity of Сhiсago Prеss.

-R.А.

Frisсh, Karl Rittеr

Kari Rittег von Frisсh r t h е г . ss i d е Ь y t h r е е g е l numЬеr of notеd асad h a v е а d i s r i n g u i s h е dс who influеnсеd him mt ology at thе Univеrsity аt thе Univеrsity of М t а n с е o f с a r е f u lе х p е г i ful oЬsеrvеr of living d е v i s i n gs i m p l е е х p е r сonditions. W h е n F r i s с h W а sa y nows to adаpt thеiг сt i n t o с o n f l i с tw i t h t h е с ] m o l o g i s t .S t u d y i n gh o сludеd that fish and irr othеrwisе сolor-blind. r a i s е dа n d k е p t m а n y t Ь l е o f с h a n g i n gс o l o r a timе. This suggеstеdto hе proсееdеd to tеst z Frisсh's findings, and tJ a dесadе. Еarly in thе с o l o r s е n s еi n h o n е y Ь t o m a k е F г i s с hw o r ] d . F r i s с h ' sf i r s t s t u d i е s shаpе.Hе nехt studiс mеnts hе disсovеrеd tl thеir fеllow workеrsiг 1920 he puЬlishеd his Ьееs.Hе undеrstood th danсеs, a round dаnсе thе hivе. Initially hе su and thе wagglе danсе 1944 thaт hе disсovеrе of rhе food sourсе fгol lowing spring hе arrivе pеrformеd Ьy bееs rеtt thе hivе, sеrvеs to сoll food sourсе.ln his fuI p е г с е i v еp o I a r i z е dI i g h t h е m o n l o n g f l i g h t sr o Е r i s с h s p е n гm u с h o | с е е d е dR i с h а r d H е r г w

Рrisсh 930s аnd wеll еstaЬlishеd Ьy rоlogiсalstudiеs.Нowеvеr, а nе of thеm сritiсs of thе synсе of morphology during thе lssistantpгofеssorat thе Uniivеrsityof Сhiсago Prеss was ts. Не nominated Form апd еr disсussеdwhy morphology of еvolutiоn, Ьut hе rеportеd ] to сonsidеr thе ninеtееnthiplеsof organismiс dеsign. So гlrеrеЬirth of intеrеst in mor:ntiеth-сеnturyпroгphologists rеlеvаntto сontеmporary dе,mundsonand Laudеr 1994). rе morphology, Ьut his Ьook h е t i сl i g h t . R е с o g n i t i o n o f t h е rlogists,lrowеvеr. Еrnst Mayr, 'nd а funсtiсlnalist to tlrе сorе, proЬably no othеr branсh of гy as for morphology: Russеll for its frеsh anаlysis of thе pri-

пrithout рurposе:Tlrс usеsof iologуапd Philсlsophу9: |renсhBiritlgуin thе Dесаdes Prеss. Studуiтtthе Histсlr1'of Еuolutiсlп Prеss. rn:JohnNlurray. M. R. Rosеand G. V. Laudеr, lemiсPrсss. MA: Наrvard r. Сambridgе' кt Hассkеlапd tЬс Struggleсlt,еr [ СhiсagoPrеss. rogrеssill,ЕuolutioпаrуB iologу' п Наt,'еL1Purposе?Сaпrbridgе, lndon:JсlhnМurray. o.o.'1*.o.

Frisсh,Karl Rittеr von (1886_1982) Karl Rittеr von Frisсh was Ьсlrn in Viеnnа to a fantily distingr.rishеd on his fathеr's sidе Ьy thrее sеnеrations of physiсians and on his mothеr's sidе Ьy a numbеr of notеd aсadеmiсs. A lovеr of ilnimals as a youth, hе wеnt on to havе a distinguislrеdсarееr lls an еxpеrimеntal physiologist. Thе tеaсhеrs who influеnсеd hirn most wеrе his unсlе, Sigmund Ехnеr' profеssor of physiology at thе Univеrsity of Viеnrra, and Riсl-rardНегtwig, profеssor of zoology at thе Univеrsity of Muniсh. Both irnprеssеdupon hirn thе сгitiсаl importanсе of сarеful еxpеrimеntation as a сornplеmеnt to his talеrrts as a thought. ful oЬsеrvеr of living animals. Frisсh rеspondеd Ьy Ьесoming а mastеr at dеvising sirnplе еxpегirnеntsto tеst thе bеhavior of animals undеr natural сonditions. .Whеn F.risсhWas a young rеsеarсhеr, his еarly work on thе аЬility of minnows to adapt thеiг сoloration to dark or light Ьасkgrounсls Ьrought him into сonfliсt with thе сlaims ot Сarl von Неss, a prominеrrt Muniсh сlphthalmologist. Studying how various animals rеspond to light, Hеss had сonсludеd that fish and invеrtеЬratеsгеspond to thе Ьrightnеssof сolors Ьut arе othеrwisесolor-Ьlind. Fгisсh, Ьoth аs а naturalist аnd аs somеonе who hаd гaisеd arrd kеpt many diffеrеnt spесiеs оf fish' knеw that somе fish arе сapaЬlе of сhanging сolor and that сеrtаin spесiesarе еspесiallyсolorful at mating timе. This suggеstеdto him that fish havе a sеnsеof сolor, a hypothеsis that hе proсееdеd to tеSt and сonfirm ехpеrimеntally. Hеss, howеvеr, rеjесtеd Frisсh's findings, and thе dеЬаtе that еnsuеd Ьеtwееn thеm lаrstеdmorе than a dесadе. Еarly in tlrе dеbatе Frisсh proсееdеd to addrеss thе quеstion of сolor sеnsе in horrеybееs.Tlrr-rsЬеgarrir wholе sеriеs of rеsеаrсhеSrhat Wеrе to makе Frisсh world-famous. Frisсh's first studiеs оf honеyЬееsеxаminеd thе insесts' sеnsеof сolor and shapе.Hе nехt studiеd thе Ьееs' sеnsе of smеll. In thе сoursе of his ехpеrimеnts hе disсovеrеd that sсout Ьееs arе somеhow aЬlе to сommuniсiltе to thеir fеllow workеrs in thе hivе thе еxistеnсе of а dеsiraЬlе food sourсе. In 192О Ьe puЬlishеd his first rеports on wlrat hе сallеd thе ..languagе''of thе Ьееs.Не undеrstood thе Ьееs,..languagе''to inr,,olvегwo distinссivеkirrds of danсеs,a round danсе and a wаgglе danсе, pеrformеd Ьy Ьееs rеtr'trningto thе hivе' Initially he supposеd that thе round danсе signifiеd а nесtar sourсе аnd thе wagglе darrсе signifiеd а pсlllеn sourсе. It wаs not until thе fall of |944 tЬat hе disсоvеrеdthat thе diffеrеnt danсеs аrе rеlatеd to thе distanсе of thе foсld soЦrсе from thе hivе and not to thе naturе of thе food. Thе following spring hе arгivеd at thе rеmarkaЬlе сonсlusiоr-r that tЬе wagglе d:rnсе, pеrforrrrеdЬy bеes геturning from food sourсеs rnorе than 100 mеtеrs from thе hivе, sеrvеs to сommuniсаtе Ьoth thе distanсе and thе dirесtion оf thе food sourсе. ln his furthеr studiеs of honеyЬееshе dеmonstratеd that thеy pеrсеivеpolarizесilight and in аdditiсlrrlrаvе an ..intеrnalсloсk.'thаt еnаЬlеs thеm on long flights to adjust to thе sun's сhanging plaсе in thе sky. Frisсh spеnt muсlr of his сarееr аt thе Univеrsity of Мuniсh, whеrе hе suссееdеdRiсhLrrdНеrtlvig in \925 as profеssor of zoologv anсl dirесtor of thе

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Frisсh Zoo|ogiсa| Institutе.In thе еаrly 1930s, with hеlp from thе Bаvariаn govеrnmеnt аnd thе Roсkеfеllеr Foundation, Frisсh madе thе Zoo|ogtсa| Institutе at Мuniсh thе most advanсеd sсiеntifiс сеntеr of its kind in Еuropе. Hе managеd to rеtаin his position throughout thе Third Rеiсh' though not without somе diffiсultiеs frorn thе Nazi authoritiеs. Atiеr Alliеd Ьon-rЬingdеstroyеd muсh of thе institutе in 1944, hе сontinuеd his studiеs in Austria, first at his summег h
Thе Galipagos

Thе Gal6pagos Arс 70 milеs long) loсat dor, to whiсh thеy aсtivе) and of rесе platе driftеd еаstеrl hot and thеrе is lit 1532, thеy wеrе ini Amеriсan novеlist madе a sour allusi ground" (1987,12 еvolutionists thеy a Thе islands soon gos Ьеing Spanish f stеrs that сrowdеi ехtinсtion' thanks t Ьrutеs providеd ехс sporadiсally by sai first in thе sеvеntее and thеn in thе еig сarry Spanish namе Thе Gal6pagos A aroцnd thе globе, < was fasсinatеd Ьy birds that livе on th Ьoth flora and faun and signifiсanсе of What did strikе Dal ganisms on thе Ga faсt that thе island Nonе of this sееm .!Иhy wouiс origins. why South Amеriса islands? Нis сuriosity piс tions of thе island

hеlp from thе Bavarian govеrnn a d еt h е Z o o l o g i с a l I n s г i t u t еa t эf its kind in Еuropе. Hе manrird Rеiсh, though not withоut \ftеr Alliеd ЬomЬing dеstroyеd ris studiеs in Austria, first at his ,fеssorof zoology at thе Univеr. :Univеrsit1'of Мuniсh in 1950, 8. Among his many honors was ;inе,whiсh hе sharеd with Kon-

o,In Dictioпаrу of Sсiепtifiс Ьеth GomЬriсh, trans. oхford:

-R.vИB.

Thе Gal6pagos Afсhipеlago Thе Galipagos Arсhipеlago is a group of 14 small islands (thе largеst aЬout 70 milеs long) loсatеd on thе еquator aЬout 500 milеs off thе сoast of Есuador, to whiсh thеy Ьеlong. Thеy arе volсaniс in origin (somе are still slightly aсtivе) and of rесеnt gеologiсal agе. Thеy wеrе formеd as thе сontinеntal platе driftеd еastеrly. Harsh, with сindеr and ash undеrground, thе сlimatе is .W,еstеrnеrs hot and thеrе is littlе or no frеsh watеr. First disсovеred Ьy in 15З2, tЬeу wеrе initially сallеd tЬ,eЕпсапtаdаs, or thе Еnсhantеd Islеs. Thе Amеriсan novеlist Hеrman Меlvillе, who visitеd thеm on a whaling trip, madе a sour allusion to this namе, dеsсriЬing thеm as ..еvilly еnсhantеd ground'' (1987, 129), adding: ..Мan and wolf alikе disown thеm'' (127). For еvolutionists thеy arе far from еvil and thеy arе сеrtаinly еnсhantеd. Thе islands soon took on thе namе of thеir most famous dеnizеns' Gal6pagos Ьеing Spanish for tortoisе. Not just any kind of tortoisе, Ьut giant monstеrs that сrowdеd thе islеs until thеir numЬеrs wеrе rеduсеd to nеar ехtinсtion' thanks to thе killing and taking Ьy marinеrs who found that thе Ьrutеs providеd ехсеllеnt farе for long sеa voyagеs. Thе islands wеrе visitеd sporadiсally Ьy sailors, сhiеfly Ьuссanееrs, аnd wеrе givеn Еnglish namеs, first in thе sеvеntееnthсеntury aftеr prominеnt pеrsonagеs (likе King Jamеs II) and thеn in thе еightееnth сеntllry aftеr worthiеs of that timе. Today, thеy сarry Spanish namеs givеn Ьy Есuador. Thе Gal6pagos Arсhipеlago was visitеd in 1835 Ьy HМS BeаgIеon its trip around thе gloЬе, сarrying Сharlеs Darwin as thе ship's naturalist. Darwin was fasсinatеd Ьy thе wildlifе, еspесially thе tortoisеs and thе many small Ьirds that livе on thе islands. As was his сustom, hе madе largе сollесtions of both flora and fauna, although as yеt hе did not truly rеalizе thе importanсе and signifiсanсе of kееping sеparatе thе individuals from differеnt islands. !Иhat did strikе Darwin at onсе was thе sееming rеlationship Ьеtwееn thе organisms on thе Gal6pagos and thе South Amеriсan mainland, and also thе faсt that thе island dwеllеrs gеnеrally had slight Ьut distinсtivе diffеrеnсеs. Nonе of this sееmеdto makе sеnsе from a сrеаtionist viеwpoint of organiс .Why origins. would thе organisms Ье similar to thе mainland organisms' and why South Amеriсa rather than Afriсa? And why thе diffеrеnсеs Ьеtwееn thе islands? His сuriosity piquеd, Darwin mullеd ovеr thе Ьiogеographiсal distriЬutions of thе island spесimеns, сonсеntrating еspесially on sеvеral spесiеs of 59З

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The Gаldpаgos Аrсhipelаgo moсkingЬird that hе knеw сamе from diffеrеnt islаnds and that sееmеddiffеrеnt physiсally. Не thought als
David Laсk, who throu Ga16pagosjust Ьеftlrе\x sivе сollесtion of thе h Amеriсаrr Мusеunr oi N Lасk at first put .rll sig War yеars on his {inding was no douЬt muсlr infl onсlmist Еrnst Мa.vr. I,: thal prесisеly at thе tir-l-rе thе synгhеsis Sуstеmаli D аrш iп's F iпсhеs (1947 )

Ьrсlught on Ьy strrrgglе Laсk's Ьook has now gi. linkеd Daгwin with thе natе еffесt of making р mаdе Dаrwin an еr,ol moсkingЬirds (sееSLrllt Aftеr Lасk,thе Gаli1 i n t h е n е o - D a r w i n i a ns y e с t n i l t U r еo f t h с ' е l е с t lorving British thinkinE faсtor. In Amеriсa, in lir turе сlf organisms' thеr есolog,vof thе islаnds п was ехplorеd and strtlr (196I), who maс.lеa lon еxistеnсеof altеrnativе Thе British Wеrе unll until thе 1970s' Thе lrr t o g е t h е rw i t h e s t l с с е s Ьесotnеonе of thе сlаss 199]r:B. R. Grant and I 2 0 0 7 ; W е i n е r 1 9 9 4 ) .V ringеd and watсlrеd anr tions аnd physiсal сhan fесts Ьrought on bу dro Works сonsгantly' аnсl l nехt. Мorеovеr' tllеrе s availaЬilitiеs arе lr sign сompеtition Ьеtwееndi Although thе Gаlipa1 еarl1,sеamеn whсl took .!7аг II who Ьuilt nn airl is now rеalization Ьy s pOrtаnt natural phеrron forts arе Ьеing mаdе ttl

Tb е Gаldpаgos Arсhipеlаgo :nt islаndsand that sееmеd diftortoisеsthat thе arсhipеlago's rеspесtivеislands.As hе triеd to had сollесtеd,hе saw that thеy ] o u l d r h е s еa l l Ь е m е r е v а г i е t i е s ,hеory? to spесialists to е his spесir-rrеns slip ovег to an еvolutionary poеdly diffеrеnt spесiеs' and this lposition that original foundегs d еvolvеdas rhеy and thеir suсal pаrt of this thinking was that u l a t i o n sl r n d s u Ь s е q u е n rs p е с i a llution's history as Ьеing fundapаttеrn was сoral-likе (his first hе madе famous in oп tbe ori:r еvolutiсlnistswho thought of n е , w i t h v а r i a t i o n sа l o n g m i n o r lf a sесondarуrolе as his thinkrgеogгаphyas a kеy support of : impoгtanсе of his visit to thе is signifiсanсе, thе grеаt Swissost impoгtantpost-orryiи sсiеnlnism,visitеd thе Gal6pagos latе : l r t h а t h i s s p е с i а lс r е a t i o n i s tv i Gal5pagos and its inhabitants. o produсеso variеd a display on ) 0 1 ' е s p е с i a l l yс h a p t е r 4 ) . H o w r thе GalripagosArсhipеlago waS though, in linе with thе gеnеral l' most would havе agrееd with ldеd to produсе thе animals and L930s,whеn Darwinian sеlесtion odеrn еvolutionary thеory. Nеoltion' was Ьorrr. Howеvеr' thеrе >agosundеr thе rrеt of nаtural sеlly among Amеriсans, that small vе. Tlrе population gеnеtiсist sес k i n gt o t h i s p r е j u d i с еЬ y a r g u i n g nеtiсdri{t,tЬе randomnеss that is ffеrеnсеsЬеrwееnGaldpagos ortusе.No onе dеniеd that sеlесtion f dеtаilsгеvеzrlеdЬy thе islands. L was an Еnglish sсhooltеaсhеr,

David Lасk, who through thе еnсotrrаgеnrеtrt сrfJulian Huхlеy lvеnt to thе lWar jrrst Gal5pagos II to stlld,Ytlrе Ьirds. Hе thеn Ьеgan ir nras_ ЬеfoгеWorld sivе сollесtion of thе Ьirds-finсhеs partiсularly-that was ownеd Ьy tlrе Amеriсan Мusеutl of Natural History in Nеw York. \Иriting up his findings, Laсk at first put аll signifiсаnt сhаngе down to drift. Rеflесting during thе Wаr yеars on his findings, Laсk swung еntirеly to a sеlесtivееxplanation. Hе Wasno douЬt muсh irrfluеnсеdby thе Gеrman-Ьorn, Amеriсan-rеsiding tах. onomist Еrnst Мaуr. Laсk roomеd with Мayr and his family in Nеw Yoгk, prесisеlyаt thе tirrlеtlrrrtlИayr wаs finishing his pro-sеlесtionсontriЬution to thе synthеsis Sуstсttt"ttiсsапd tlэe Оrigiп of Speсies (1942). Lасk irrguесi in Dаrшiп's Fitlсbеs\1947) that all diffегеllсеslrеtwееnthе spесiеsarе ad:rptivе, Ьrought on Ьy strugglе Ьеtwееn groups for геsourсеs.Although thе titlе of Laсk's Ьook has now givеn thе popular nаn]е to thе finсhеs and has publiсly linkеd Darwin with thе island inhaЬitants,it also had thе somеwhat unfortu. natе еffесt of making pеoplе think that it wаs thе finсhеs ехсlusivеly thаt madе Darwin an еvolutionist. At lеаst, if n()t morе important, Wеrе thе moсkingЬirds (sееSrrllowaу 1982,). Aftеr Laсk, thе GаlzipilgosЬirds Wеrе onе oi tlrе primе piесеs of еvidеnсе in thе nеo-Darwiniаrrsynthеsis.Howеvеr, сontrovеrsyсorrtinuеdovеr thе ехaсt nаturе of tЬе sеlесtivеforсе that lrad Ьгotlght on diffегеnсеs.Laсk, fol. lowing British tЬir-rking,had madе сompеtition Ьеtwееn groups thе kе1' faсtor.In Amеriса, in linе with gеnегalthinkiпg in that сountry aЬout thе rrа. turе of organisпrs,thеrе was morе еnthusiaslт for a position that madе tlrс есology оf thе islаnds morе signifiсant.This viеw of sеlесtion and its еffесts was ехplorеd and strongly dеfеndеd Ьy Сalifornia Ьiologist RoЬеrt Bowman (1967),whсl madе а long visit to thе islаnds in 19.52_195З.Hе found that thе ехistеnсеof аltеrnirtivеfoсld suppliеs Was thе kеy firсtor in sеlесtivесhаngе. Thе British wеrе ltt-tit-nglrеssеd, and tlrus mаrtеrs rеrrrаinеdat an impаssе Llntiithе \970s. Tlrе htlsЬ:rnс]-and-wifе tеаm оf Pеtеr and Rosеmary Grant' togеthеrrvith ir suссеssionof сoworkегs ilnd studеnts,Ьеgan what lras sirrсе Ьесomеonе of thе сlassiс long.tеrm studiеs of tlatural sеlесtion(Grant l986, 1997;B. R. Grаnt аnd P. R. Grarrt1989;P. R' Grant and B. R. Grant 1995, 2007; !Иеinеr 7994)..sИorkingon thе islеt Dа;lhnе Major (sее figurе), thе1' ringеd and watсhеd and rесordеd еvеry Ьird, noting thе numЬеr of fluсtua. tions and physiсal сlrangеsfronr onе yеar tO thе nеxt' еspесiallynoting thе еf_ fесtsЬrought on Ьy drought and Ьy rесord rаinfzrll.Thеy found that selесtion works сonstаntly' irrrсltlrat сhаngеs сan oссur rapidly froпr onе yеar tO thе nеxt. Мorеovеr) thеrе sееtllsto Ье truth in thе сlz.riпrthzrtfood suppliеs and аvailabilitiеsirrе a signifiсant faсtol. in sеlесtir,есhangе, Ьut not ехсluding сompеtitioll Ьеtlvееndiffеrеnt groups. Although tlrе Gаlipagos has Ьееn ЬattеrеdЬ,vhuman oссupanсy' from thе еarly sеamеn wlro took thе tortoisеs,through thе Amеriсаn forсеs in \Иorld War II who Ьuilt alr airЬasе thеrе' to thе prеsеnt Есuadorian fishеrmеn,thеrе is now rеalization Ьy sсiеntists and govеrnmеntаl authoritiеs of what an important natural phеnomеnon thе Gal6pagos Arсhipеlago rеprеsеnts.Sеrious еf_ forts arе Ьеing mаdс to protесt and сonsеrvе thе islаnds and thеir inhаЬitants.

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Тhе GаlсipаgсlsАrс..hipelаgсl

Меlvillе, Н. 1987.Thс Prosе Piесеs,18.J of HеrтпаnМеluil еds.Еvanston,II,: S u l l o w a yF, . J . 1 9 8 2 .Г thе Historу of Bkl Wеinеr,J. 1994.ThеF York: Knopf. Wright, S. 19З1.Еvolu 1 9 З 2 .Т h е r о l с еvоlutiorl.Proсее

Galton, Franсis

Thе islеt Daphnе Маjor in thе Gаlipagсls Arсhipеlago,whеrе Pеtеr and Rоsеmаry Grant did thеir dесirdеs-longstudy of Dаrwin's finсlrеs.Thе volсаniс origins oi thе islеt, а hill with thе top Ьlown off anсl а сratеr formеd within, arе сlеarly visiblе.It has Ьееn possiЬlеto work out rеlationshrps Ьеtwееntlrе dеnizеnsof thе islаnds from thе sеquеntialordеr in whiсh thе islands wеrе formеd, Ьy volсаrriсaсtivity' аs thе еаrth'splаtеsslippеd aгound its surfасе.

Now thеy arе onе of thе most popular of dеstinations for tourists. Darwin's visit to thе island, rathеr than Меlvillе's, has provеn to havе thе longеrlasting еffесt. BIBLIOGRAPHY Bowman, R. 1961. МorpholrlgiсаI Diffеrепtiаtioп апd Аdаptаtiсlп iп thе Gаldpаgos Fiпсhеs. Bеrkеlеy:Univеrsitr,of Саlifoгr-riаPrеss' Grant, B. R., and Р. R. Grant. 1989. Еuolutionаrу Dу,паmics of а Nаturаl Populаtiс.lп:,ГhеLаrgе Сасtus Fiпсh of tbе Gаlipаgos, Сhiсago: Univеrsity of Сhiсago Prеss. Grant, P. R. 1986. Ессlklgу апd Еutllutiсlпof Dаrtuiп's Fiпсhеs' Prinсеtоn, NJ: Pritrсеton Univеrsity Рrеss. 199l. Nаtural sеlесtionаnd Darwin's finсhes.SсiепtifiсАmеriсап, OсtoЬеr: 82-87. Grаnt, P. R., аnd B. R. Grаnt' 1995. Prеdiсting miсrоеvоlutionarу rеsponsеsto dirесtional sеlесtionon hегitaЬlеvаriation. Еu oluti on 49 : 241 -25 1. 2ОО7, Hсlш апd Whу Spесiеs Миltiplу: Thе Rаdiаtiсlп of Dаrtuiп's Fiпchеs. Prinсеton' NJ: Prirrсеton Univеrsity Prеss. Laсk, D. |947. Dаru,'itis Fiпсhеs.СamЬridgе: СanrЬridgе UrrivеrsityPrеss. Larson, Е. J. 2001. Еuolиtirlп's Workshоp: Сod апd Sсiеnсе сln tЬс Gаlipаgos Islапds. Nеw York: Basiс Books. Мayr, Е. |942, Sуstеtttаtiсsапd thе Оrigiп of Spесiеs. Nеw Ytlrk: СolumЬrа Univегsitv Prеss.

Franсis Galton was to pursuе a саrееr ir study mathеmatiсs' Darwin and Galton win (1731-1802), a would Ье a сruсiаl faсt, it was Galton's thе idеa оf improvin hе сoinеd thе tеrm e Sevеrаl ,Yеarsaftе Galton organizеd an Еuropеan ехploratior latitudеs,longitudеs сation of numеriсala him. Hе puЬlishеdhi in 1852 and was awa сausе of his prесisе,с Ьook aЬout his jсlurг

book for amatеur an triumph. It wеnt thr Phoеnix Prеss rеissuе Galton Was an aсtiv yеars. FIis сommеnt mattеrs (е.g.,latitud intеrеstеd in mеtеor сharасtеristiсof a hi1 Thе part of Galtor aftеr hе had rеad Dal and сultivatесl plants able to Galton that t to dеmonstrаtе that . hеritеd. Hе attеmptе Talеnt and Сhагaсtе

Gаlton Islеs.In PiаzzаTаlеsапd Оtbеr Меlvillе,H. 1987.Thе Еnсаntadas, or Еnсhzrntесl PrrlsePiесеs'18З9-1860:Тhе Nоrthц'еstеrtrNешbеrrуЕditiсltt
Galton, Franсis (1'822_1911)

ipеlago,whеrе Pеtеr and f Darwin'sfinсhеs.Thе эlown oif and a сratеr fоrmеd o work out rеlаtionships quеntiаlordеr in whiсh thе е еafth'splatеsslippеd around

гinationsfor tourists. Darwin's ls provеn tо havе thе longеr.

апd Аdаptаtiсlп iп thе Gаldpаgt.>s ss. Dупаmiсs of а Nаtиrаl Populаs. Сhiсagсl:Univеrsity of Сhiсago уiп'sFiпсhеs.Pгinсеton,NJ: rcs.SсiспtifiсАmeriсап, oсtoЬеr: сrоеvolutionaryrеsponsеsto ,olиtion49:241-251. е RаdiаtЙlttсlf Dапuiп's Finсhes. пbridgеUnir,еrsityPrеss. d Sсicпсе tlп thе Gаldpаgos ;les.Nеr,l,York: СolumЬia

Franсis Galton Was born nеar Birmingh:rm,Еngland. Hе originаlly intеndеd to pursuе a сarееr in mеdiсinе, Ьut hе switсhеd to СamЬridgе Univеrsity to study mathеmatiсs' influеnсеd Ьy his сOusin Сharlеs D;rгwin (1809_1882). Darwin and Galton wеrе grandsons Ьy differеnt marriagеs of Еrasmus Dаrwin (1731_1802),a physiсian' sсiеntist,poег' аnd invеntor. Сharlеs Darwin would Ье a сruсial influеnсе on Galton throughout muсh оf his сarееr. In faсt, it was Galton's rеading of oп the o rigiп of Speсiеs (1 859) that gavе him thе idеa of improving tlrе human raсе throllgh sеlесtivеЬrеесling,for whiсh hе сoinеd thе tеrm сltЗеniL.s. Sevеral yеaгs aftеr grаduating from СamЬridgе with aп ordinary dеgrее, Galton оrganizеd and finanсеd an Afriсan ехpеdition that rеsultеd in thе first Еuropеan ехploration of northеrn NamiЬia. Hе made сarеful mеasurеmеntsof latitudеs, longitudеs' and altitudеs, rеflесting his lifеlong intеrеst in thе appliсation of numеriсal and quantitativе mеthoс.lsto whatеvеr happеnеd to intеrеsr hinr. Не puЬlishеd his rеsr'rltsin tЬеlourпttl
597

598

Gаltoп Маgаzine (1865)' and in thе Ьook that followеd, Hеrеditаrу Gепicts(1869). In both thе artiсlе and thе Ьook Galton triеd to dеmonstratе that whаt hе rе.Гhе fеrrеd tо as ..tаlеntand сharaсtеr'' wеrе inhеritеd. Ьоok traсеd pеdigrееs of judgеs, statеsmеn'and othеrs, Galton's Ьasiс assumption was that if hе piсkеd an еminеnt judgе, for еxamplе, thаt judgе'sсlosеstmalе rеlativеs(е.8., fathеr аnd son) had a grеatеrсhаnсе оf bеirrgdistinguishеdthan thosе furthеr rеmovеd (е.g.,grаndfathеr' grandson). !7omеn wеrе not inсludеd, proЬaЬly rеflесtingЬoth Viсtorian prеjudiсе and mаlе dominanсе in Viсtorian soсiеty. Galton сonсludеd thаt his rеsults suppoгtеd his hypothеsis.Although othеrs pointеd out that еnvironmеnt (е.g.,thе fathеr'sgood position might еnsurеa plumЬ joЬ for his son) с
In thе Unitеd Statеs,p involuntary stеrilizatiс ..fееblеmi dеfiсiеnt or followеd with intеrеsl .$Иhеn thе Nazis сamе that rеsultеd in thе stеr .World .!Var II, еugеniс .!Иhilе еugеniс Еuropе. сrеditеd with impсlrtal printing, mеtеorolоgy,

в|вLIoGRAPнY

Brookеs, NL.2ОО4.Ехtrе Gаltoп. Nеw Yoгk: Bulmеr' |vl.20o3.Frаnс J o h n sH o p k i n sU n r v Forrеst,D.W. |974. Frаt York:Tаp[ingеrPuh Galton,F. 1852.Rесеnt Jourпаl of thе Roуа | 8 5 3 .T r о p i с аSl |855 . Тbе Аrt o1 Сouпtriеs.London: 1865.Неrеdita з1'8_327. 1869. Herеditаr l889. NаturаlIr 2ОО1.Thе Аrt сц Сouпtriеs.London: G i l l h a m 'N . W . 2 0 0 1 .А Birth of Еugеzliсs.N K е v l е s ,D . 1 9 9 . 5l.п t h е] Prеss. Kiihl, s. 1'994'Thе Nаzi Paul, D. B. 1995.Сoпtrс H i g h l а n d sN. J : H u n Pеarson,K.1914-1930. C а m Ь r i d g еС: а m Ь r R е i l l v .P . R . l 9 9 l . Т Й сS tllе UпitеdStаtcs.B.

Gamе thеory

Thе study of аnimal Ь Ь е t w е е ni n t u i t i o n a r r d invеstigаtion. Еfforts t сal tools сallеd gamеs A gamе in this sеnsс ing whеn thе outсomе othегs. Тhus а gamе l

Gаme Тheorу 'd, Hеrеditаrу G eпius (1869). dеmonstratеthаt what hе rееd.Thе Ьook traсеd pеdigrееs ;iс assumption was that if hе ;е'sсlosеstmalе rеlativеs (е.B.,

stinguishеdthan thosе furthеr l Wеrеnot inсludеd' probably r m i n a n с еi n V i с t o r i a n s o с i е t y . s hypothеsis.Although othеrs lgood position might еnsurе a с o r r е l а r i o nG, a l t o n a t t е m p t е d мrote Неrеditаrу Gепiиs, Gal'эn for thе еstimаtеd15 million r natural aЬilitiеs. LIе also was alyzе statistiсally, partiсularly lot еasy to do with humаn bе)есausеthеy wеrе еasy to grow rts hе fоund that sееd diamеtеr r frоm progеny of laгgе_sееdеd Lnof tlrеpopulation as a wholе. ;tiсal propеrty that has Ьееn rео{ dif{еrеntсlаssеs of mutцal us intеrnationаl stoсks). Galton mеtеrsof parеntal sееds vеrsus . Hе had drаwn tlrе fiгst rеgrеs_ еssionсoеffiсiеnt.Latеr, Galton lе orgаnizеdаn inthropomеtriс сhiЬitionlrеld in South Kеnsingl Sсiеnсе Gallеriеs of thе South эd. Соllесting qllantitativе data a Ь l еt o d е m o n s r r а r еr е g r е s s i o n эristiсs(е.g.,hеight). Whеn hе |vеrеdanothеr impoгtаnt statislong forеarпrs).Hе сalсulatеd riсh hаvе Ьееn сomputеd sinсе. rnd thеir сlassifiсation; his work ng аs a forеnsiсtесhniquе. 'ant findings in Nаtиrаl lпherig6еs,inсluding Karl Pеarson. A d Galton in formulating sratisting еugеniсsand thе idеa was linist еrrvironmеntat thе еnd of ourаgеd thе sеlесtivе rеproduсеniсs aimеd to еliminatе thе rееly' nеgativееugеniсs prеvailеd.

In thе Unitеd Statеs, passаge of state еugеniс stеrilization laws rеsulted in thе involuntarystеrilization of thousands of individuals rеgardеd to Ье mеntally ..fееЬlеmindеd.'' defiсiеntor Еugеniс dеvеlopmеnts in thе Unitеd Statеs wеrе followеd with intеrеst in Еuropе and еlsеwhеrе' partiсularly in Gеrmany. !Иhеn thе Nazis саmе to powеr thеy pаssеd аn involцntаry stеrilization law that rеsultеd in thе stеrilization of hundrеds of thousands of individuals. Aftеr !Иorld !Иar II' еugеniс stеrilization gradually еndеd in thе Unitеd Statеs and Еuropе.rWhilееugеniсsis Galton's most wеll_known lеgасy, hе also must bе сrеditеd with important aсhiеvеmеnts in fiеlds аs divеrsе as statistiсs' fingеrprinting, mеtеorology' and еxploration. BlвLIoGRAPHY Brookеs'I\^.2004.ЕхtrеmеМеаsures:The Dаrk Visioпsаnd Bright Idеаsof Frапсis Gаltoп. Nеw York: BloоmsburуPuЬlishing. Bulmеr,М. 2003. Frапсis Gаltoп: PioпeеrrэfНеrеditvапd Bioтnеtrу.Bаltimоrе: JohnsНopkins UnivеrsityPrеss. Foгrеst,D.w.1974. FrаltсisGаltсlп:Thе Lifе апd'V/
-N.vИG.

Gamе thеory Thе study of animal Ьеhavior thrivеs оn paradoxеs, Ьaffling inсonsistеnсiеs bеtweеn intuition and еvidеnсе that еngаgе attеntion аnd stimulatе furthеr invеstigation. Еfforts to rеsolvе suсh paradoхеs rеly inсrеasingly on analytiсal tools сallеd gamеs. A gamе in this sеnsеis a mathеmatiсal modеl of stratеgiсintеraсtion, arising whеn thе outсomе of an individual's aсtions dеpеnds on aсtions takеn Ьy othеrs. Thus a gamе has thrее kеy сomponеnts. Fiгst, thеrе arе at lеast two

599

Gаme Thеorу intеraсting individuals, сallеd playеrs. In an еvolutionary gamе' thе sеt of playеrs is an есotypе' thаt is, a population of animals in a givеn есologiсal еnvironmеnt (for ехamplе, a populatiоn of spidеrs in a grassland haЬitat and a riparian population of thе samе spесiеs would form two diffеrеnt есotypеs). Sесond, еaсh playеr has a sеt of fеasiЬlе stratеgiеs thаt is сonstrainеd Ьy thе informаtion struсturе of thе intеraсtion (for ехamplе, animals сan сondition thеir Ьеhavior on whеthеr thеy arе ownеrs or intrudеrs only if thеy arе awarе of suсh rolеs). Third, thе pattеrn of intеraсtion must Ье wеll dеfinеd and aссompaniеd by a formula for how еaсh playеr's rеward from thе intеraсtion dеpеnds on its stratеgy and on thosе of thе othеr playеrs. In еvolutionary gamеs, thе rеwards arе mеasurеd in tеrms of еxpесtеd futurе rеproduсtivе suссеss. For a gamе to Ье usеful, it must Ье possiЬlе to idеntify a stratеgyor stratеgiеs from among thosе fеasiЬlе as thе ..solution'' for a givеn purposе. In an еvolutionary gamе' this is thе Ьеhavior еxpесted to еvolvе Ьy natural sеlесtion. If a Ьеhavior is fixеd in a rеal population, thеn it must at lеast Ье truе that еvеry fеasiЬlе altеrnativе Ьеhavior would yiеld a lowег rеward, othеrwisе thе altеrnativе Ьеhavior would havе sprеad into thе population. Thus thе rеlеvant solution сonсеpt-introduсеd by John Мaynard Smith (1982)is thаt of an еvolutionarily staЬlе stratеgy (ЕSS), a population stratеgy that yiеlds a highеr rеwагd than any fеasiЬlе mlltant stratеgy (sее also Dawkins

r976).

Sсiеntistsstrivе to unravеl a paradoх Ьy еstaЬlishingсonditions for an ЕSS to ехist in a modеl population with assumеd сomponеnts, and Ьy analyzing its propеrtiеs whеn it doеs eхist. If thе ЕSS in thе modеl population fails to matсh obsеrvеd Ьеhavior in thе rеal population, thеn onе or morе of thе assumptions arе modifiеd-aЬout есotypе' information struсturе and stratеgy sеt' of pattеrn of intеraсtion and rеward. Thе ЕSS is rесalсulatеd as oftеn as nесеssary. In othеr words, if a paradoх of animal Ьеhavior ехists, thеn wе havе wrongly guеssеd whiсh gamе Ьеst modеls how a rеal population intеraсts. Tо rеsolvе this paradoх' Wе must guеss again-if nесеssary,rеpеatеdlyuntil еvеntually wе guеss сorrесtly. Gаmеs arе valuaЬlе Ьесausеthеy allow sсiеntiststo ехplorе thе logiс of a vеrbal argumеnt rigorously, аssuming Ьiologiсally rеalistiс есotypеs' and to dеtеrminе whеn it is truе and whеn it is falsе. Gamе thеory oftеn dеmonstratеs what is diffiсult to intuit. Foг еxamplе' gamе thеory has shown that viсtory Ьy strongеr animals neеd not imply that strengthis Ьеing assеssеdin сontеsts' and has yiеldеd a tеst for suсh аn ЕSS, namеly, whеthеr еnеrgy rеsеrvеs of losеrs сorrеiatе positivеly with сontеst durations. For furthеr dеtails of this ехamplе and othеrs, sее Меstеrton-GiЬЬons and Adams (1998). BIBLIOGRAPHY Dawkins, R. 1976. The SelfishGепe. oхford: Oхford UnivеrsityPrеss. l4aynard Smith,J. 1982.Еuolutiсlпапd thе Tbеorу of Gаmеs.СamЬridgе: СamЬridgеUnivеrsityPrеss. Меstеrton-Gibbons, М., and Е. S. Adаms.1998.Animal сontеstsas еvoluttonary gamеs. Americап Sсieпtist 86: 334-341.

-NI.М.-G.

The cenеticаl Thс

Sir R. A. Fishеr's TЙe l 9 3 0 , i s с е l е Ь г а г е da s t lесtion and Mеndеlian Fishеr from Fishеr's diс p r o Ь l е m s o f g е n е t i с sa r Thе first sеvеn сhap D a r w i n ' s m е с h a n i s mt l sidеrеd thе first two сl mеntal thеorеm of natu thеsе two сhaptеrs асс F i s h е r ' sf i r s t с h a p t е tion with, altеrnаrivе stratеs that on thе Mеn o f a p o p u | а t i o n ' sv a г i а sistеnt proЬlеm for D; had lеd Ьiologiststo ab w i n . s a с с е p t a n с еo f Ь l е trolIingmutаtionbес Ь l е n d i n gr h е o r y .B е с a u mutation ratеs' Fishеr vivе naturаl sеlесtion а F i s h е r ' ss е с o n d с h a ; natural sеlесtion.Thrе m a t h е m a t i с s .Т h е f i r s ..tr4althusianparamеtе of thеir lifе historiеs.l Fishеr partitions into Е mеasurе of thе ratе of natural sеlесtion.For l

еqual to thе [additivе] Fishеr's ..fundamеntal h i s n а t u r a l s е l е с г i o nr h с а l p r o o f t h а tс u m u l a naturаl sеlесtionon mr B y а n d l a r g е .t h е m i с a s е s ,s u с h а s d o m i n a сеding thеorеtiсal worl ехpands his thеorеtiс с а U s е so f g е n е t i сv а r i a Thе last fivе сhаpr h u m а n p o p u l а t i o n s 'p с е n t r a l o Ь s е r v а t i o ni s е t i е ss t г u с t u r е st h е Ь i r I n t h е f i n a l с h а p r е r .F i

Thе GеnеtiсalThеory of Natural Sеlесtion 601 volutionary gamе' thе sеt of playnals in a givеn есologiсal еnvirоna grasslandhaЬitat and a riparian two diffеrеnt есotypеs). Sесond, Lаtis сonstrainеdЬy thе informa. е, animalsсan сondition thеir ЬеLеrsоnly if thеy arе awaге of suсh Ье wеll dеfinеd and aссompaniеd .om thе intеrасtion dеpends on its r еvolutionarygamеs' thе rеwards 'roduсtivеsuссеss. llе to idеrrtif)ra stratеgy or stratе_ rtion'' for a givеn purposе. In an lесtеdto еvolvе Ьy natural sеlесtion, thеn it must at lеast Ьe truе uld yiеld a lowеr rеward, othеr;prеadinto thе population. Thus ryJohn Maynard Smith (19tt2)(ЕSS),a population stratеgy that tutantstratеgy(sее also Dawkins эstаЬlishingсonditions for an ЕSS еd сomponеnts'and by analyzing i in thе modеl population fails to rtion, thеn onе or morе of thе аsrformatiоn struсturе and stratеgy ]hе ЕSS is rесalсulatеdas oftеn as I animal Ьеhаvior еxists, thеn wе tdеlshоrv а геаIpopulation intег; аgain-if nесеssary'rеpеatеdlysсiеntiststо ехplorе thе logiс of a ogiсally rеalistiс есotypеs' and to falsе. Gаmе thеory oftеn dеnronrplе, gamе thеoгy has shown that . that strеngthis Ьеing аssеssеdin r ЕSS, nаmеlу, whеthеr еnеrgy rеltеst durations.Fоr furthеr dеtails GiЬЬons and Adаnrs (1998).

)xlЪrdUnivеrsityPrеss. эorуof cаmеs.СаmЬridgе:

i. Anilrrrl сontе\ts ... """'Ifi]xZ-".

The Geпeticаl Thеorу of Nаturаl Selection (R. A. Fishеr) Sir R. A. Fishеr's Tbе Genеtiсаl Theorу of Nаtиrаl Selectioп, puЬlishеd in 19З0, is сеlеЬгatеdas thе fiгst mа;.orrесorrсiiiationof Darwiniirn natural sеlесtion and Mеndеlian hеrеdity.Thе 12-сhаptеrmanusсrtpt,сrеatеd Ьy Mгs. Fishеr from Fishеr's diсtation, was thе сulmination of Fishеr's thоught on thе problеnrsof gеnеtiсsand nаtural sеlесtionЬеgun in thе latе 1910s' Thе first sеvеn сhaptеrs of cепetiсаl Tbeorу sеt out Fishег's synthеsis of DarwinЪ nrесhanismof natцrаl sеlесrionand Меndеlian gеnеtiсs.Fishеr сonsidеrеdthе first two сhaptегs' on thе naturе of inhеritanсе and thе ..fundamеntal thеorеm of natuгal sеlесtion,'' thе most important of thе Ьook. [ndееd, thеsеtwo сhaptеrs aссomplish thе kеу piесе of thе rесonсiliation. Fishеr's first сhaptеr сonsidеrs impliсations of a synthеsis of natural sеlесtiorr with, altеrnativеly, Ьleпding аnd Меndеlian inhеritаnсе. Hе dеmоn_ stratеsthat on thе Меndеlian thеory' naturаl sеlесtionmay Ье thе mаin саusе of a population's variaЬility. Thе dеmonstration importantly rеsolvеd a pегsistеntproЬlеm for Darwin's thеory of dеsсеnt with rnodifiсation, onе that had lеd Ьiologiststo аЬandon nаtural sеlесtionas an еvolutionaryсausе.Dar. winЪ aссеptаnсеof blеnding inhеritаnсеrеquiгеd him to imаginе саusеsсontrolling mutation Ьесausе of еnormous mutation ratеs dеmandеd Ьy thе Ьlеndingthеory. BесausеМеndеlian hеrеdity did not dеmand suсh еnormous mutation ratеs, Fishеr was aЬlе to еliminаtе thеsе сontrolling сausеs and rеvivе natuгal sеlесtionas an important еvolutionary саusе. Fishеr's sесond сhаptеr dеvеlops, mathematiсаlly, his gеnеtiсal thеorу of natural sеlесtion.Thrее kеy еlеmеntsmay Ье distillеd from Fishеr,s ..hеavy'' mathеmatiсs.Thе first is а mеasurе of avеragе population fitnеss: Fishег's ..Маlthusian paramеtеr,''thе rеproduсtivе valuе of all gеnotypеsat all stagеs of thеir lifе historiеs. Тhe sесond is a mеasurе оf variation in fitnеss,whiсh Fishеr partitions into gеnеtiс and еnvironmеntal сomponеnts. The third is а mеasurеof thе ratе of inсrеasеin fitnеss,that is, thе сhangе in fitnеssduе to natural sеlесtion.Еor Рishеr, ..thеrarе of inсrеasеof fitnеssof any spесiеsis еqual to thе [additivе]gеnеtiсvarianсе in fitnеss'' (p. 35).This last еlеmеntis Fishеr's..furrdamеntalthеorеm o1 natural sеlесtion,'and is thе сеntеrpiесеof his nаtuгal sеlесtionthеory. Under this ruЬriс, Fishеr thеn offеrs a gеomеtгlсal proof that сumulativе еvolution is primarily thе rеsult of low prеssurеsof natural sеlесtionon mutations of small еffесtBy and largе, thе middlе сhaptеrs of Geпеticаl Theс>rуarе ехplorations of сasеs,suсh аs dorninanсе,sехual sеlесtiоn,аnd rnimiсry' tO supрort thе prесеdingthеorеtiсalwork' Nеvеrthеlеss,in thе fourth and fifth сhaptеrs' Fishеr ехpands his thеorеtiсal disсussion to morе gеrrеral issuеs сotlсеrning thе сausеsof gеnеtiсvariation' irrсiudingrаndom gеnеtiс drift. Thе last fivе сhaptеrs of Gепetiсаl Thеorу ехplorе natural sеlесtion in human populations' partiсularly soсial sеlесtiorrin lruman fЪrtility. Fishеr's сеntral oЬsеrvation is that thе dеvеlopmеnt of есonomiеs in humаn soсiеtiеs struсturеs thе Ьirth ratе so that it is invеrtеd with rеspесt to soсial сlass. In thе final сlraptеr,Fishеr offеrs stratеgiеsfor сountеring this еffесt.Dеspitе

602

The Gеnеtiс Basis of ЕvоlutionaryСhangе Fishеr's еspousal of this еugеniсs thеsis in this part of thе Ьook, hе intеnds thе disсussion to Ье takеn as an insеparaЬlе ехtеnsion of thе prесеding part. Tbe Gепetiсаl Thеorу of Nаturаl Seleсtioп is a point of dеparturе in еvolu. tionary thought, rеsponsiЬlе in part for thе originаtion of thеorеtiсal population gеnеtiсs and what is сommonly сallеd thе modеrn synthеtiс thеory of .!Иright's еvolution. Gепetiсаl Theorу was followеd Ьy Sеwall and J. B. S. Нaldanе's major works in 19З1 and 1,9З2,rеspесtivеly. Fishеr's viеws on thе rolе of natural sеlесtionin еvolution arе widеly aссеotеdtodаv. в|вLIoGRAPHY Fishеr,R. A. 1930 [1958].Тhе GепeticаlТhеorуof NаturаlSеlесtioп.2nd еd.Nеw York: Dovеr Publiсations.Rеlеasеdin a variorum еdition by oхford Univеrsity Рrеssin 1999, editedЬy J. H. Bеnnеtt. Haldanе,J. B. s. 19З2.The Саusеsof Еuolиtion.London:Longmans. .Wright, s. 1931.Еvolutionin Меndеlianpopulations.Gепеtiсs16:97-159.

-R.А.s.

Thе Genetiс Bаsis of Euolшtionаrу Сbапge (Riсhard Lеwоntin) In1974, Riсhard Lеwontin, a profеssor at Hаrvard Univеrsity, puЬlishеd an important assеssmеnt of thе statе of еvolutionary gеnеtiсs. Lеwontin's 1974 Ьook,The Gепetiс Bаsis of Еuolutioпаrу Сhапge, сonsidеrеd thе trеmеndous сhangеs within evolutionary gеnеtiсs wrought Ьy thе introduсtion of tесhniquеs from molесular Ьiology and thе suЬsеquеnt dеvеlopmеnt of thе nеutral thеory of molесular еvolution. Lеwontin's Ьook is notеworthy for its analysis of thе naturе of еvolutionary gеnеtiсs and thе dynamiсs of sсiеntifiс сontfovеrsy and сontrovеrsy rеsolution. Lеwontin and his сollеaguе, J. L. HuЬЬy, hаd touсhеd off a molесular revоlution in 1966 whеn thеy introduсеd thе bioсhеmiсal tесhniquе of еlесtrophorеsis as a mеans of rеsolving gеnеtiс diffеrеnсеs at thе molесular lеvеl. Lеwontin Ьеliеvеd that this nеw еlесtrophorеtiс analysis of gеnеtiс variaЬility rеsolvеd thе еarliеr disputе Ьеtwееn thе сlassiсal and balanсе positions ovеr variability and sеlесtion. Thе high lеvеls of variaЬility detесtеd with еlесtrophorеsis sееmеd to support thе Ьalanсе position and thе importanсе of Ьalanсеd polymorphisms in еvolution. The сlassiсаl position's Ьеliеf was that most mutations wеrе dеlеtеriousand most wеrе sеlесtionpurifying. Thеy strugglеd to ехplain еlесtrophorеtiсvariaЬility until Мotoo Kimura and othеr Ьiologists Ьеgan to arguе that most of thе dеtесtеd polymorphism was in faсt nеutral, nеithеr sеlесtеdfor nor against. In Тbе Geпetiс Bаsis of Еuolиtioпаrу Сhапge, Lеwontin еmphasizеd thе сontinuity Ьеtwееn thе еarliеr сlassiсalЬalanсе сontrovеrsy and thе thеn-raging nеutralist-sеlесtionist сontrovеrsy. For him, thе nеutralist position was rеally just thе сlassiсal position Ьrought in linе with nеwеr moleсular rеsults. Whilе this intеrprеtation of thе сontrovеrsy makеs a goоd сasе foг сontinuity in еvolutionary gеnеtiсS, it nеglесts thе growing сontriЬution of bioсhеmiсal rеsеarсh to thе dеvеlopmеnt of molесular еvolution.

Having arguеd that Lеwоntin advanсеs an tiсs is inеvitaЬle. The с rеsult of a dееpеr,irrе and nеutralist position aЬility; thеir fondnеss сеpting оr rеjесtingvа еmЬraсеd сhangе and Ье aсtivеly maintainеd hеld сonviсtions rеgar his еlесtrophorеtiс dat inspirеd its transformа Tbe Gепetiс Bаsis o1 duсing еvolutionary g сarеful analysis of thе . сapturеs how gеnеtiс 1 Lеwontin, informatioп Ьody of data that wou and rеfinеd. In light of rеlationship bеtwееn t] tion, Lеwontin arguеd plaсеd with modеls th: Indееd, Tbe Gеnеtic B thе rеal proЬlеms of е standing thе intеraсtiv

вlвLIoGRAPHY

Diеtriсh'М. R. 1994.Th lourпаl of thе Histo Нubby, J. L., and R. С. l hеtеrozygosity in na Drosophilа psеudoo Kimura,М. 1983.TЙeN СambridgеUnivеrs Lеwontin,R. С. 1974.Тt Сolumbia Univеrsit Lеwontin'R. С.' аndJ. L hеtеrozygсlsity in nа hеtеrozygosityin na 542595-609.

Geпetics аnd the I (ThеodosiusDoЬz

With grеat сharisma a Ьесamе a rallying poin giп of Spесies (1'937\l

Gеnеtiсsand thе origin of Spесiеs 60З part of thе Ьook' hе intеnds thе rsion of thе prесеding part. is a point of dеparturе in еvolu.iginationof thеorеtiсal popula:hе modеrn synthеtiс thеory of .tХ/right,s and J. B. S' ly Sеwall spесtivеly.Fisher's viеws on thе :ly aссеptеdtoday.

f NаturаlSеIеctioп.2ndеd. Nеw ' r u mе d i t i o nЬ y o х f o r d U n i v е r s i t y London:Longmans. о n s .G е п с t i с s1 6 29 7 _ | , , - * . o . , .

Сhаnge lаrvard Univеrsity' publishеd an )nаry gеnеtiсs.Lеwontin's 1974 шge, сolsiderеd thе trеmеndous ;ht Ьy thе intrоduсtion of tесhеquеnt dеvеlopmеnt of thе nеuin's Ьook is notеworthy for its сs and thе dynamiсs of sсiеntifiс

Having arguеd that onе сontrovеrsy has Ьееn transformеd into anothеr' Lеwontin advanсеs an ехplanаtion for why сontrovеrsy in еvolutionary gеnеtiсs is inеvitaЬlе. Thе сonnесtion and pеrsistеnсеof thеsе сontrovеrsiеs WaS a rеsцlt of a dееpеr, irrеsolvaЬlе idеologiсal сonfliсt. Advoсatеs of thе сlassiсal and nеutralist positions hеld a сonsегvativе attitudе toward сhangе and vаriaЬility; thеir fondnеss for staЬility lеd thеm to sее sеlесtion as a mеans of aссеpting or rеjесting variations. Advoсаtеs of thе Ьalanсе position' howеvеr, еmbraсеdсhangе and variaЬility; thеy favorеd thе idеa that variation сould Ье aсtivеly maintainеd in a population Ьy Ьalanсing sеlесtion.Thеsе dееply hеld сonviсtions rеgarding thе valuе of сhangе еxplainеd for Lеwontin why his еlесtrophorеtiс data did not rеsolvе thе сlassiсal-balanсе сontrovеrsy, but inspirеd its transformation. Thе Gепetiс Bаsis of Еuolutionаrу Сhаngе should not bе undеrstood as rеduсing еvolutionary gеnеtiсs to сonfliсting idеologiеs. Lеwontin prеsеnts a сarеful analysis of thе сhаllеngеs of produсing a thеory of gеnеtiс сhangе that сapturеs how gеnеtiс proсеssеs intеraсt and dеvеlop ovеr timе. Aссording to Lеwоntin, information aЬout molесular level сhangеs was finally providing a Ьody of data that would allow thеoriеs of еvolutionary gеnеtiсs to Ье tеstеd and rеfinеd. In light of nеw molесular data, Lеwontin сlaimеd that thе еntirе rеlationship Ьеtwееn thеory and faсt would havе to Ье rесonsidеrеd. In addition, Lеwontin arguеd that thеoriеs of individual gеnеs would havе to Ье rеplaсеd with modеls that сonsidеrеd gеnomеs and thеir сomplех intеraсtions. Indееd' Тhе Gепеtic Bаsis of Еuolutionаrу Сhапge еnds with thе сhargе that thе rеal proЬlеms of еvolutionary gеllеtiсs сan only Ье addrеssеd Ьy undеrstanding thе intеraсtivе сontехt of allеlеs. вIвLIoGRAP|.]Y

ad touсhеd off a molесular rеvoЬioсhеmiсal tесhniquе of еlес. Liffеrеnсеsat thе molесular lеvеl. :tiс analysis of gеnеtiс variaЬility ;siсalаnd Ьаlanсе positions ovег f variaЬility dеtесtеd with еlесposition and thе importanсе of :lassiсalposition's Ьеliеf was that rе sеlесtionpurifying. Thеy strug. rtil Motoo Kimura and othеr bi:есtеdpolymorphism was in faсt ,he Gеnetic Bаsis of Еuolutioпаrу ity Ьеtwееn thе еarliеr сlassiсalсontrovеrsy. еutra1ist-sеlесtionist Ьrought in position сlassiсal ;t thе

Diеtriсh,М. R. 1994. Thе originsof thе nеutralthеoryof molесulаrеvolution. Jourпаl of thе l{istorу of Biologу 27: 21_59. HubЬy,J. L., and R. С. Lеwontin.1'966.A molесularapproaсhto thе studyof gеniс hеtеrozygosity in naturalpоpulationsI. Thе numЬеrof allеlеsat diffеrеntloсi in Drosophilаpsеudoobscиrа. Gепеtiсs54 577_594. Kimuгa,М. 1983. Tbе Nеиtrаl Thеorу of Мolесulаr Еuollltioп. СamЬridgе: СamЬridgеUnivеrsityPrеss. Lеwontin,R. С. 1974. Тhе Gепеtiс Bаsisof ЕuolиtioпаrуСhапge.Nеw York: ColumЬiaUnivеrsityPrеss. Lеwontin,R. С., and J. L. НuЬЬy.1966.Ь molесularapproaсhto thе studyof gеniс hеtеrozygosity in naturalpopulations.II. Amount of variationand dеgrееof hеtеrozygosityin naturalpopulationsof Drosophilа psеиdoobsсurа.Gепеtics -М.R.D. 54:595-609.

intеrprеtationof thе сontroversy rtionary gеnеtiсs' it nеglесts thе :h to thе dеvеlopmеnt of molесu-

.!Иith grеat сhаrisma and a passion fоr thе subjесt' Thеodosius DoЬzhansky Ьесamе a rallying point for thе еvolutionary synthеsis. Geпеtiсs апd the origiп of Speсies (19З7) was his prinсipal сontriЬution to that movеmеnt' and

Genetiсs аnd thе Оrigiп of Speciеs (ThеоdosiusDoЬzhansky)

604

Gеnеtiсsand thе Origin of Spесiеs it Ьесamе an еssеntial tеХt in еvolutionary Ьiolоgy. On onе |evel, Geпеtiсs is a splеndid summary of еvolutionary gеnеtiсs in thе 1930s' Ьoth zoologiсal and Ьotaniсal. It Ьrought togеthеr divеrsе information and сrеatеd an еasy-to.undеrstаndmodеl for еvoiution lеading to nеw spесiеs.It also prеsеntеd an unеxpесtеd lеvеl of sophistiсation and сorrfidеnсеto Ьiologists suspiсious of еvolutionary studiеs. Likе no othеr сontriЬution to the suЬject,,Gепetiсs gave a Ьurst of еnеrgy to spесiation studiеs as a resеarсh program. i\4uсh of Gепetiсs survеyеd knowlеdgе aЬout thе gеnеtiс struсturе of populations. Reсеnt dеvеlopmеnts in teсhniquе had givеn gеnеtiсistssеnsitivе tools for monitoring nеW mutations, сhangеs in gеnе frеquеnсy, and сhangеs in сhrоmosomе struсturе. DoЬzhansky prеsеntеd сonsidеrablе data on thе еxtеnt of this variation in Ьoth laЬoratory and wild populations. Hе also dеsсriЬеd еxpеrimentаl systеmsthat monitorеd сhangеsto thе gеnеtiсstгuсturе of populations ovеr timе and ovеr сhanging еnvironmеntal сonditions. In part, DoЬzhansky's survry сеlеЬratеdthе hard-еarnеdеmpiriсal sidе of population gеnеtiсs.It also aimеd to prеsеntthе suЬjесtas rigorous, with thе еvo. lutionary sсiеntistsin full ехpеrimеntalсontrol of thеir data. DoЬzhansky dеfinеs еvolution in narrow tеrms: a сhаngе in thе frеquеnсy of allеlеs within a population. This is purposivеly opеrational. ceпetiсs offеrs many еxamplеs of suсh a сhange.It also prеsentsa dеtailed disсussionоf mесhanisms driving thosе сhangеs.This disсussion,along with thе latеr disсussion of isolation and divеrgеnсе,makе for thе two thеorеtiсal spinеs in Geпetiсs. Dоbzhansky arguеd natural sеlесtion drivеs adaptаtion and is a prinсipal agеnt in shifting thе gеnеtiс struсturе of populations. Sеlесtion usеs thе raw matеrial of gеnomе variation rеsulting from random mutation as wеll as from thе many othеr gеnеtiс and сhromosomаl pгoсеssеsat Work within organisms. Although potеnt' sеlесtionwas not DoЬzhansky's only еvolutionary mесh.sИright's..shifting anism. Hе was hеаvily influеnсеd Ьy Sеwall Ьalanсе'' thе.Wright's ory of population gеnеtiсs and notion of adаptivе landsсapеs (sее \Хiright 19З7, 19З2). !Иright's idеas alsо еmphasizеd population sizе and struсturе' migration, mutation prеssurе,аnd сhanсе. Мuсh of a wholе сhaptеr in Geпetlсs is dеvotеd to dеsсriЬing Wright's approaсh. In faсt, many еvo.Wright's lutionary Ьiologists lеarnеd aЬout modеls from rеading Genеtiсs. For Dobzhansky, shifting Ьalanсе аnd adaptivе landsсapеs Werе еssеntial tools for еxplaining thе gеnеtiсsof еvolution. Spесiation involvеs morе than simply сhangе in allеiе fгеquеnсiеs. For Dobzhansky, it rеquirеd isolation and divеrgеnсе.This is thе sесond thеorеtiсal spinе in Geпеtiсs. DoЬzhansky ехaminеd Ьoth proсеssеsin dеtail lеading to a dеfinition of spесiеsas rеproduсtivеly isolatеd and physiologiсally inсapaЬlе of intеrЬrеedingwith othеr groups. onсе isolatеd' divеrgеnсеrеsultеd from Ьoth dirесtional and random proсеssеs.DoЬzhansky arguеd thаt in thе сontinuum of lifе, spесiеsWеrе thе only ..natural''units. Thеir uniquе gеnеtiс сonfiguration, isolatеd and following a pесuliar dеstiny' Was сеntral to that thinking.

H o w p o p u l a t i o n sb t thе l930s. Мany disсi mесhanisms'' wеrе pr. сhaniсal' physiologiса i n t h a t d i s с u s s i o n .G e и t a n с е o f g е o g r a p h i сa l twееn two spесiеs sеrv сhapter in Geпеtics is сеssеsсlosе off thе tap FoI|owing \0Иrighг.l gеnсе largеly in tеrms thе partiсular Ьalanсе adaptationist. Еvеn wh h e t h o u g h t s е l е с t i o nw : tеnsity. and it frеquе DoЬzhansky prеsеntе p г е s s u r е sh a d Ь е е nd i s spесiation. Famously, though it was ехtеrnal uаls failеd to Ьrееd so ing a nеw speсiеs. In thе widеr framе, J еvolution within spесi rеproduсtivеly isolatе goriеs (е.g.,nеw gеnе additional mесhanism сеssеs of miсroеvolutitl Kеy to Gеnеtiсs's tm and еmpiriсаl studiеs pеriod's аpproaсh to е q u е s t i o n sа n d Ь u i l t с a r this with сlosе tiеs to r I n p a r t . D o Ь z h а n s k yr ь tal Ьiologistsattaсking skеptiсs from othеr d Sympathеtiс сollеaguе tionary studiеs.Thе pr Ь i а U n i v е r s i r у 'G е п е t i Ь е с o m еа n o u t | е tf o r o Ьiology, that thеory ur 199з). DoЬzhansky puЬlishе i n | 9 4 l а n d a t h i r di n w а s i n t е n d е da s G е п е s i g n i f i с а n tс h a n g е st о s y s t е m а t i сс h a n g е sо l :с

Gеnеtiсsand thе origin of Spесiеs 605 llogy. On оnе lеvеl, Geпеtiсs s in thе 1930s' Ьoth zoologi: informatiorr and сrеаtеd an lg to nеw spесiеs.It also prеand сorrfidеnсеto Ьiologists rhеr сontгiЬution to thе suЬ'ion studiеsas a rеsеarсh prot thе gеnеtiс struсturе of popl а d g i v е n g е n е t i с i s t ss е n s i t i v е r gеnеfrеquеnсy'and сhаngеs rtеd сonsidеrablеdata on thе wild populations.Hе also dеhangеsto thе gеnеtiс struсturе еnviroIlmеntalсonditions. In -еarnеdеmpiriсal sidе of popЬjесtas rigоrous,with thе еvol of thеir data. .ms:a сhangе in thе frеquеnсy ivеly opеrational. Gепetiсs ofrеsеntsa dеtailеddisсussion of ssion,along with thе latеr disr t h е t w o t h е o г е t i с e sl p i n е s i n on drivеs adaptlrtion and is a : of populations.Sеlесtion usеs from гаndom mutation as wеll Эmal proсеssеsаt work within nsky'sоnly еvolutionary mесh..shifting Ьalanсе'' thеИright's эn оf adаptivе landsсapеs (sее rphasizеdpоpr.rlаtionsizе and :hanсе.Muсh of a wholе сhap''sapproaсh.In faсt, many еvonodеls fronr rеаdirrg Geпеtiсs' tivе IandsсapеsWеre еssеntial rngе in аllеlе frеquеnсiеs. For nсе.This is thе sесond thеorеtЬоth proсеssеsin dеtail lеаding 'latеdand physiologiсally inсaсе isolatеd,divеrgеnсеrеsultеd DoЬzharrskyarguеd that in thе г а l . .u n i t s .T h е i r u n i q u е g е n е t i с iar dеstiny, was сеntral to that

How populations bесamе isolаtеd was a suЬjесt of сonsidеraЬlе study in thе 1930s.Мany disсiplinеsсontriЬutеd to that sr.rЬjесt' and many ..isolating mесhanisms''wеге proposеd (е'g., gеographiс, есologiсal, Ьеhаvioral' mесhaniсal,physiologiсal). Anything thаt prеvеntеd gеnеtiс ехсhangе сountеd in that disсussion.Geпеtiсs survеysprominеnt ехamplеs' strеssingthе importanсе of gеographiс and physiologiсal mесhаnisms. Stеrility in hyЬrids Ьеtwееntwo spесiеssегvеd as а spесial сasе study in this disсussion. A wholе сhaptеrjn Geпеtics is dеvotеd to this topiс, illr"rstratinghow isolаting pгoсеssеsсlosе off thе t;rp of gеnе flow. .!7right's Following shifting Ьalanсе thеоry, DoЬzhansky ехplainеd divеrgеnсеlargеly in tеrms of sеlесtion and drift, with сirсumstanсеs influеnсing thе partiсulаrrЬаlanсе of forсеs. Impoгtantly, DoЬzhansky is not a knее.jеrk adaptationist.Еvеn whеn it plаyеd a dеtеrminant гolе in shaping organisms' hе thought sеlесtionwas many layеrеd.It frequеntlyshiftеd dirесtion and irrtеnsity,and it frеqrrеntlyprеssеd populations in сontradiсtory dirесtions. Dobzhansky prеsеntеd еxpеrirтеntal sсеnarios in whiсh suсh сontгadiсtory hаd Ьееn distinguishеd.DoЬzlransky did not rеqr.tirеdivеrgеnсеf
(t06

c еoffroу Sаiпt-Н ilаirе to sее a muсh strongеr rolе for sеlесtion in thе еvolutionary proсеss. Using onе of his powеrful mеtaphors' StеphеnJay Gould (1983), no grеаt lovеr of univеrsal adaptationism,rеfеrrеd to this as thе ..hardеning''of thе synthеsis, although othеrs (for ехamplе, Rusе 1999) sее it as il natural dеvеloprnеntof a sсiеntifiс thеory in thе faсе of nеw еvidеnсе. в|BLIoGRAPHY Сain, J. A. 1993.Сommоn рrсlЬlеrns and сoopеrativе srllutions: organizаrtionаl aсtivityin еvolutionarystudiеs|9з6_\947./sls84: 1_25. Dobzhansky,T. 19з7. Gепеtiсsапd tbе Оrigiп tlf Spесies.Nеw York: СrllumЬia UnivеrsityPrеss.(Sесondеdition] 941, third еdition1951.) -. 1970' Cепеtiсsсlf thе ЕurllutiсlпаrуPrtlсеss.Nеw Yоrk: ColumЬiirlJrrivеrsitу Prеss' Gould, S. J. 1983.Thе hardеningсlfthе synthеsis. In M. Grеnе,еd.,Dimепsiotlsof Dаrшiпiпsm.СamЬridgе:СamЬridgеUnivеrsityPrеss. Rusе, М. 1999. Муstеrу of М1'stеriеs: Is Еuolutioп а Soсiаl Сoпstruсtiсlп? СamЬridgе,МA: HarvardUrrivеrsity Press. Wright,s. 1931.Еvolutionin Меndеlianpopulаtions.Gепеtiсs16:97_I59. |932.Thе rolеsof mutation'inЬrееding, сrossЬгееding and sеlесtiоntn еvolution.Proсееdiпgsof thе Siхth IпtеrпаtioпаlСoпgressof Gепеtiсs|: -I.С. з56_366.

Gеoffroy Saint-Hilairе,Ёtiеnne (1772-1844) Еtiеnnе Gеoffroy, known as Saint.Hilаirе, was Ьorn in Ёtampеs on April 15' 1772. Sent to Paris to study for holy сlrdеrs,hе еntеrеd mеdiсal studiеs in ordеr to fulfill his sсiеntifiс amЬitions. Plaсеd undеr thе patronagе of thе сrystallographеr Rеn6-JustеHaiiy, whom hе savеd from almost сеrtаin dеath in SеptеmЬеr 1'792, in Junе |79З Geoffroy Was аppсlintеd profеssor of zoology at thе newly сrеatеd Мus6um n:rtional d'histoirе naturеllе, not without somе Ьеlatеd opposition. |n 1795 hе invitеd Gеorgеs Сuviеr to sharе his own apаrtmеnt in Paris; thеy would writе fivе innovativе joint еssays.Unlikе Сuviеr, who stayеd homе to Ьеttеr his сarееr' in 1798 Gеoffroy aссеptеd thе invit:rtion to join thе ехpеdition to Еgypt organizеd Ьy Gеnеral Napсll6on Bonapartе. His work on thе fauna of thе Nilе rеgion wаs notеd in Franсе, as Wеrе his privatеlу сOmmuniсatеd spесulations on lifе and еlесtriсity, inсrеasingly suspiсious in thе сonsеrvativесlimatе lеading to thе Napolеoniс Еmpirе. Bасk to Рaris in 1802, shortly to lеavе again for Spаin and Portugal, hе was Ьadly lagging Ьеhind Сuviеr. Hе was madе a mеmЬеr of thе Institut only in 1807 аnd was appointеd profеssorat thе nеwly сrеatеdsсiеnсеfaсulty in Pагis in 1809. Thе Ьulk of his major work was puЬlishеd aftеr 181.5,аnd during thе 1820s Gеoffroy lеd thе sсiеntifiс oppсlsition to thе сonsеrvativе govеrnmеnts in powеr, of whiсh Сuviеr was a suppoгtеrand аt timеs a rеprеsеntativе. During thе 18З0s lris pеrsistеnt аttaсks on his dесеasеdformеr friеnd, his mystiсal Ovеrtonеs'and his philosophiсal prеtеnsionsсontriЬutеdto his isolаtionwithin thе Pаrisian sсiеntifiс сommunity, though his rеpшtation was сonsidеraЬlе thrсlughсrutЕuropе. Gеoffroy's Philoso1lhieапсlto|11iquе (t818), his еulogiеs оf Lаmаrсk, and

h i s r е p е a t е dI i p s е r v i с or pеriphеral naturalis politiсal сonsеrvatism. Buffon's hints сonсеrn, сеivеd vеrtеbratеsas Ь( timеs аlmost invisiЬlе Ьratеd studiеs on thе v posе mammalian aud Hеgеl and provеd' in L ogy еstaЬlishеd Ьy Riсl mесhaniсаl сonstrаint for thе diffегеnt..Ьа| a n d е v е n с l а s s е s .D i f f е diffеrеnt animal form 1 8 2 0 s a n d 1 8 3 0 sh е t с ditions mightmесhan gan dispositions, mod thеorеtiсal Ьoldnеssm: all animаl forms. His с vеrtеЬratеs gavе Сuviе h е a t е d ,f a m o u s d i s p u t е s с i е n с е si n l 8 3 0 . A I r h Wеnt to Cuviеr. many I anatomy.

B|вLIoGRAPHY

Appе|,ToЬy A. 1987.Tht bеforeDапuiz. oхftl С o r s i .P . | 9 8 8 .T h еA g еBеrkеlеy:Univеrsityr Gеoffroy Sаint-Hilairе,Ё. Мarvis. L е G u y а d е rН . . 2 0 0 4 ,Й i , Nаturаlist.Сhiсago:l

Gillеspiе,JohnH.

John Gillеspiе has Ьееn рattеrns of molесular е sеlесtion in variaЬlе еn w o r k h a s i n с l u d е dt h е d е s с r i Ь еn а t u r а I s е l е с t v а r i o u s p a t t е г n so Г m o | diсtions of thosе' and o A studеnt of Kеniсl l970 fгom thе Univеrs

Сillespie 'lrееvolutionar,vproсеss. Using З o u l d ( 1 9 8 З ) ,n o g r е e t l о v е r o i rе ..hardеnit-lg'' of thе synthеsis' : it as а nаturаl dеvеloрrnеnt of

гivеsolutiotls: Organizаrtionаl ls 84:1-2-5. Spcсiеs.Nеw York: Ссllr-rп.rЬiа : с l i r i o 1n9 5 1 . )

. . \ е w Y l , г k :( o l t r l n h i . l I l l i r ' е г s i r y In М. (irеnе, ed.,Dimепsioпs of ity Prеss. l а Soсiаl СoпstrЦсtio|1? '>ns.Gепеtiсs | 6: 97_1 59. :rossЬrееding and sеlесtion rn nаl Сoпgrеss of Gепеtiсs 1z

-J.С.

'2-1844) s Ьorn in Ёtampеs оn April 15, еrrtегеd mеdiса[studiеsin сlrdеr thе patronagеof thе сr1,strrllog. almost сеrtain dеath in Sеptеm. rtеd profеssоr of zoсllogy at thе urеllе,not withtrr"rt somе Ьеlаtеd r г o s h e r еh i s t , r v t tа p а r t m е n ri l l saуs.Unlikе Сltviеr,who st;ryеd ]сеptеdthе invitation to join thе pol6onBonapartе.His work on .еt .ls Wеrеhis privаtеlyсomnltl:rеasinglуsusPiсi()usin tlrе ссrnFlmpirе.Baсk ttl Paris in 1802, l' hе was Ьadiv lagging Ьеhind orrlyin 1807 anс]wаs appointеd i r rР a r i si n 1 8 0 9 .Т h е Ь u l k o f h i s rringthе l820s Gеoffroy lеd thе llmеnts in polvеr, of whiсh Сui v е .D u r i n gt h е I 8 З 0 sh i s p е r s i s . his mystiсal ()vеrtonеs'аnd his l l а t i t t rцl ' i t h r пт h еP a r i s i l r l rs с i е n l l s i d е r а h ltеh r r l u g ' h o uЕru r t l p е . ), his еulсlgiеsof Lamarсk, and

his rеpеatеdlip sеrviсе to transformist thеoriеs madе him а hеro of radiсirl or pеriphегal naturalists who aссusеd Cr'rviеrоf prostituting his sсiеnсе to politiсal сonsеrvatism. Dееply influеnсеd Ьy IJauy's сrystallography and Ьy Buffon's hints сonсеrning thе unity of animal typеs, Gеoffroy initially сonсеivеdvеrtеЬratеs:ls Ьеing сomposеd of thе samе sеt of organs and pаrts, at timеs аlmost invisiЬlе in somе fаmiliеs, fully dеvеlopеd in оthеrs. His сеlеЬratеd studiеs on thе vеstigiаl prеsеnсеin rеptilеs of all thе parts that сom_ posе mammalian auditory organs еliсitеd thе admiration of Goеthе and Hеgеl and provеd, in his еyеs' thе thеory of analoguеs, or, in thе tеrminology еstaЬlishedЬy Riсhard owеn, homology. Не Ьеliеvеd that struсtural or mесhaniсal сOnstr.lints during dеvеlopmеnt miglrt hаvе bееп rеsponsiЬiе for thе diffеrеnt ..Ьalanсing'' of various sеts of parts in diffеrеnt farrriliеs and еvеn сlassеs.Diffеrеnt ratios of ехprеssion of an organ or parts induсеd diffеrеnt animаl forms, thus produсing diffеrеnt funсti
Gillеspiе,John H. (Ь. L944| John Gillеspiе has Ьееn thе most prominеnt сhi.rmpionof thе argumеnt that pattеrnsof molесulаr еvolution аrе ехplainеd bеttеr Ьy thе aсtion of nаtural sеlесtiсlnin vаriaЬlе еnviгonmеntsthan Ьy tlrе so-сallеd nеutrаl thеory. His work has inсludеd thе dеvеlopпrеntof сomplеx mathеmatiсal modеls that dеsсriЬе natural sеlесtion undеr varying сonditions and thе сomparison of vаrious pattеfns of moleсulаr vаriation within and among spесiеsto thе prеdiсtiсlnsof thosе, arrd otlrеr, modеls. A studеnt of Kеniсhi Kоjima, Gillеspiе rесеivеd his doсtoral dеgrее in \970 from thе Univеrsity of Tехas at Austin. Не approaсhеd thе quеstion of

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Gillеspie molесular variation Ьy сonsidеring rеlativеly simplе modеls of how nаtural sеlесtion might opеrate whеn somе forms of a protеin wеrе favorеd under some еnvironmеntal сonditions and othеrs under diffеrеnt сonditions, with сonditions сhanging from onе gеnеration to thе nехt. In this еarly work' Gillеspiе Ьеgan еxploring thе сonditions undеr whiсh varying еnvironmеnts сrеatеd balanсing selесtion, а form of sеlесtion in whiсh fitnеss diffеrеnсеs among allеlеs that сontrollеd protеin variation arе сanсеlеd out ovеr thе long tеrm Ьy thе fluсtuations in еnvironmеntal сonditions. At first glanсе, this сanсеllation of fitnеssdiffеrеnсеswould sееm to dеvolvе into thе nеutral thеory, whiсh postulatеs that thе majority of diffеrеnсеs among protеin variants produсе no diffеrеnсеs or only slight diffеrеnсеs in thе fitnеss of individuals that сarry thеm. Although in somе сasеs modеls of variaЬlе sеlесtion prеdiсt thе samе pattеrns as do nеutral modеls, many of thе long-tеrm pattеrns of gеnе suЬstitution arе diffеrеnt. In partiсular, modеls of variaЬlе sеlесtion makе diffеrеnt prеdiсtions aЬout thе еxistеnсе of a molесular сloсk, whiсh is thе apparеntly rеgular pattегn with whiсh onе form of а protеin rеplaсеs anothеr within a groupr suсh as mаmmals or Ьirds, ovег long pеriods. Gillеspiе's work showеd that whеthеr a сloсk еmеrgеs dеpеnds upon thе prесisе distriЬution of fitnеss diffеrеnсеs and thе timеsсalе ovеr whiсh onе mеasurеs suЬstitutions. Thеsе rеsults stand in stark сontrast to many aspесts of widеly aссеptеd nеutral modеls, сalling thosе modеls into quеstion. Bеsidеs offеring thе most сomprеhеnsivе altеrnativе to thе nеutral thеory, Gillеspiе is rеsponsiЬlе for a numЬеr of othеr insightful сontriЬцtions. Не has dеvеlopеd statistiсal approaсhеs to tеsting hypothеsеs aЬout еvolutionary ratеs for Ьoth molесular data and data on quantitativе сharaсtеristiсs, suсh as Ьody sizе or morphologiсal traits. Gillеspiе's ехplorаtions of fitnеss disсounting-how an individual might сompromisе pеrformanсе in onе сondition with thе nееd to pеrfoгm in many, variablе сonditions-lеd to a num. Ьеr of advаnсеs Ьy othеrs in thе arеa of lifе history еvolution in a variaЬlе еnvironmеnt. His studiеs of thе еvolution of mutation and migrаtion ratеs in variablе еnvironmеntsсhаngеd Ьiologists'viеws of how еvolvaЬlеthosе ratеs might bе. Thе highly sophistiсatеd mathеmatiсs that Gillеspiе еmployеd has rеstriсtеd his rеadеrship among gеnеral еvolutionary Ьiologists, many of whom may know him morе for his dеlightful introduсtory tехtЬook on population gеnеtiсs.Нowеvеr, his work on protеin еvolцtion is thе major altеrnаtivе to nеutral thеory and, as suсh, oссupiеs a prominеnt position in thе disсiplinе. BIBLIOGRAPHY Gillеspiе,J.H. |991. TЬе Саusеsof МolесularЕuollttioп.Nеw York: Oхford UnivеrsityPrеss. 2ОО4.PopulаtiсlпGепеtiсs:А СoпсisеGuidе' 2nd еd. Baltimorе:Johns -J.T' Hopkins UnivеrsityPгеss.

Goеthе, Johann.W

Johann !Иolfgang von ( Ьorn in 1749 in Frankfi p i r е . H е с o m p l е t е dD i . .Wеrthеr) io 1774. Fаи strugglе with sесulariza сasts and Ьroadеns thс Goеthе's death in.Wеim Goеthе's rеputation . prominеnсе as a naturа thе produсt of vеrsе' a Ьlе. Goеthе's approaсh the skelеton and thе р as a wholе' dеspitе thе knowlеdgе of thе parts thе wholе. In 1784, Gс formulatеd a vеrtеЬrаll skull сould Ье dеrivеd Goеthе, сould Ье rесog сurrеd. Goеthе's approaсh to еxpеnsе of саusа formа a Ьull has bееn givеn l opеd thе horns that hе, thе tеlеologiсal approaс сizеd thе adaptationist's iсal trait in tеrms of sеlс aЬout loсating rеal ехр manuеl Kant, who famс ganiс naturе who would to tеlеologiсal languagе tory еlеmеnts arе to Ье еvеr, distanсеs himsеlf 1 naturе of an organism rs nеvеrthеlеss ехplanator human ехpеriеnсе. Thе kind of thing Go. thе organization оf plal Thе modifiсation thеrес as diffеrеnt plants. Hе s ing various plants as thе a paradigm of suсh a pl tions of thе lеaf: ..All tnl thе lot of thеm suggеs lady, сonvеy to you in .

Goеthе y simplе modеls of how natural lf а protеin wеrе favorеd undеr undеr diffеrеnt сonditions, with to thе nехt. In this еarly work, dег whiсh varying еnvironmеnts tion in whiсh fitnеss diffеrеnсеs rtion аrе сanсеlеd out ovеr thе :ntal сonditiоns. At first glanсе, sееmto dеvolvе into thе nеutral y o f d i f f е r е n с е sa m o n 8 p r o t е i n ht diffеrеnсеsin thе fitnеss of inе сasеsmodеls of variаЬlе sеlесl modеls,many of thе long-tеrm [n partiсular' modеls of variaЬlе t thе еxistеnсе of a molесular :n with whiсh onе form of a proas maпrtnalsor lэirds, ovеr long Lеthеra сlосk еmеrgеs dеpеnds :fеrеnсеsand thе timеsсalе ovеr еsults stzrndin stark сontrast to rodеls'сalling thosе modеls into altеrnativеto thе nеutral thеory, 'hеr insightful ссlntriЬutions. Hе :inghypothеsеsaЬout еvolutionl o n q ц a n t i t a t i v ес h a r a с t е r i s t i с s , Эillеspiе'sеxplorations of fitnеss promisе pеrformanсе in onе сonrriaЬlесonditions-lеd to a numГеhistory еvolution in a variaЬlе I m u t а t i o na n d m i g г a t i o n r а t е s i n iеws of lrow еvolvaЬlе thosе ratеs ihat Gillеspiе еmployеd has rеzolutionary Ьiologists' many of rl introduсtoгytехtЬook on popltеin еvolution is thе major altеr'piеsa prоminеnt position in thе

|uolutiсln,Nеw Yoгk: oxford )uide.2nd еd. Bаltimorе: Jоhns

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Goеthе,Johann

.Wolfgang von (1749-|832)

Johann rХ/olfgangvorr Goеthе, wеll known for his litеrerrymastеrpiесеs' was Ьorn in 1749 in Fr;rnkfurt am Мain, during thе timе of thе Holy Romаn Еm'V/еrtber (Thе Sorrows of Yor.rng pirе. Hе сomplеtеd Die Leidеп dеs juпgeп Wеrthеr)in t774. Fаust I, Goеthе's luminous, riсh treatmеnt of Еuгopе's strugglеwith sесulaгization,was first puЬlishеd in 1808. Fаust Il, whiсh rесаsts and Ьroadеns thе еpisodеs of Fаust 1, was сomplеtеd a уeaf Ьеforе Goеthе'sdеаth in Wеinrar in 1832. Goеthе'srеputatiOn as a poеt should not' howеvеr, есlipsе his insight and prominеnсеas а naturаl sсiеntist.Indееd, Goеthе Ьеliеvеd that sсiеnсе was thе prodr'rсtof vеrsе, and thаt art аnd thе study of naturе wеrе insеparaЬlе. Goеthе's approaсh to nrorphology is a finе сasе in point. For Goеthе' thе skеlеton and thе parts of thе organiс body wеrе to Ье lookеd upon as a wholе, dеspitе thе anаtomist's proсlivity for dissесtion. Physioiogiсаi knowlеdgеof thе parts is dеpеndеnt upon thе (artist's)vision of thе form of thе wholе. In1784, Goеthе Wrotе an еssay on thе intеrmaхillary Ьonе and formuiatеda vеrtеЬral thеory of thе skull' maintaining that thе Ьonеs of thе skull сould Ье dеrivеd from thе vеrtеЬraе. Thе initial form, ассording to Goеthе, сor"rldЬе rесognizеd dеspitе rhе сonsidеraЬlе сhangе thаt had oс. сurrеd. Goеthе's approaсh to morphology doеs not еmphasiZе саusсl fiпаlis at tЬe еХpеnsеof саusа formаlis. Tlrе produсtivе аpproaсh is not to maintain thаt a Ьull has Ьееn givеn horns to butt, Ьut to ask how hе might havе dеvеlopеdthе horns that hе, in faсt, so usеs.Goеthе's rеmarks, and his rеjесtion of thе tеlеologiсalаpproaсh, to somе еxtеnt arе prесursory to thosе who сritiсizеd thе adaptationist's program-tЬе Ьusinеssof undеrstanding еvеry Ьiologiсal trait in tеrms of sеlесtivеprеssurеs.Nеvеrthеlеss, Goеthе is morе sаnguinе abotlt loсаting rеal ехplanatory еlеmеnts in organiс naturе than, say, ImmаnuеlKant, who famously dеniеd that thеrе would еvеr Ье a Nеwton of organiс naturе who would ехplаin еvеn a singlе Ьladе of grass without an appеal to tеlеolоgiсallanguagе.Kant is, pеrhaps,сorrесt' if the appropriatе ехplanatory еlеmеnts arе to Ье undеrstood in tеrms of саusа е|fiсiens. Goеthе, howеvеr' distanсеs himsеlf from this kind of viеw Ьy maintaining that whilе thе naturеof аn organisrnis not еxplainеd еntirеly in mесhaniсal tеrms, thеге arе nеvеrthеlеssехplanatory forms that сan Ье apprеhеndеd on thе Ьasis of human еxpеriеnсе. Thе kind of thing Goеthе has in mind сan Ье illustrated Ьy his thinking on thе organization of plants. Thе lеaf, aссording to Goеthе, is a Ьasiс organ. Thе modifiсation thеrеof issuеsin thе various parts of a singlе plant, as wеll as diffеrеnt plаnts. Не sееms to havе thought that by systеmatiсallyoЬsеrving various plants as thе di1fеringinstаntiationsof a dеvеlopmеntalpгinсiplе, a paradigm of suсh a prinсiplе' onе сould undеrstand thе possiЬlе pеrmutatiorrsof thе lеaf: ..All thеir shapеsaге alikе, yеt nonе thе sanrеas thе nехt and thе lot of thеm suggеstsa sесrеt law, a saсrеd puzz|e. Сould l only, swееt lady, соnvеy to you in a word thе happy solution.'' Thе poеt's oссupаtion is

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Goldsсhmidt frеquеntly thought to ехprеss сonсisеly in vеrsе that whiсh is diffiсult tсl artiсulatе. So, too, thе Ьiologist in Goеthе sееmsto sееk to еxprеss thе elusivе forms that undеrwritе thе ехpеrienсеs of naturе. BIBLIoGRAPнY Kant' I. 2000. Сritiquе of thе Potuеrof lиdgmепt.P. Guyеr,еd. СamЬridgе: СambridgеUnivеrsityPrеss. Riсhards,R. J. 2002. Тhе RсlmапtiсСoпcеptiсlпof Lifе. Сhiсаgo:Univеrsityof Сhiсago Prеss. Sеаmon,D., аnd А. Zajonс,еds.1998.Goеthе'sWауof Sсiепcе:A Рhепrlmепologу сlf Nаturе. AlЬany: StatеUnivеrsityof Nеw York Prеss. Stеuеr,D.2002.In dеfеnsеof еxpеriеnсе: Gоеthе'snaturalinvеstigations and sсiеntifiссulturе.In [,. Sharpе' ed.,СаmbridgеСompаnion to Goеthе, 160-168. СamЬridgе: СamЬridgе Univеrsity Prеss.

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Goldsсhmidt,Riсhard Bеnеdiсt(1878_195s) Riсhard Goldsсhmidt was onе of thе most сontrovеrsial gеnеtiсistsof thе twеntiеth сеntury. Known as a skillеd ехpеrimеntalistand a сrеativеthеorist' his idеas about thе naturе of thе gеnе and thе rolе of systеmiсmutations (or largе rеаrrangemеntsof сhromosomеs) in еvolution havе Ьееn сonsidеrеd hеrеtiсal, whilе at thе samе timе thеy hеlpеd to сrystallizе thе so-сallеd modеrn synthеsis' whosе partiсipants wеrе' at thе vеry lеast, unitеd in thеir opposition to Goldsсhmidt. Мorе rесеntly' StеphеnJay Gould (1982, in his introduсtion to thе rеprint of Goldsсhmtdt's Tbе Маteriаl Bаsis сlf Еuolutioп) and othеrs (е.g.,Diеtriсh 2003) havе rееvaluatеd Goldsсhmidt and arguеd that his idеas dеsеrvе at lеast as muсh сonsidеration as thе prеvailing dogma of adaptationism. Riсhard Goldsсhmidt Was Ьorn in 1878 in Frankfurt am Main into a prominеnt Gеrman Jеwish family and grеw up in a wеll-to.do miliеu. Hе Ьеgan his studiеs of mеdiсinе in HеidеlЬеrg' attеnding lесturеs of Ьoth Otto Biitsсhli and Carl GеgеnЬaur. Нowеvеr, his rеal intеrеstwas zoology, and in 1898 hе movеd tо Мuniсh tо study with Riсhard Hеrtwig. His first aсadеmiс appointmеnt Was as Hеrtwig's assistant in Muniсh. As part of his tеaсhing dutiеs hе organizеd thе laЬoratory in сomparativе anatomy' whiсh in part еxplains his vast knowlеdgе of animal morphology' anatomy, аnd сell Ьiology. In his own rеsеarсh hе foсusеd on proЬlеms of gеnеtiсsand сytology, еspесially on thе proЬlеm of sех dеtеrmination. Gсlldsсhmidt workеd with thе Gypsy motЬ Lуmапtriа, whose gеographiсal variants, whеn matеd to еaсh othеr, produсеd an assortmеntof so-сallеd intеrmеdiatеintеrsехеs.To ассount for thеsе intеrmеdiatеforms, Goldsсhmidt prоposеd a dynamiс and quantitativе modеl of gеnеtiсsthat was Ьasеd on thе undеrlying physiologiсal aсtion of gеne produсts, henсе thе namе physiologiсal gеnеtiсs.Thе Ьasiс idеa of physiologiсal gеnеtiсs Was that diffеrеnt variants of gеnе produсts should havе diffеrеnt physiologiсal propеrtiеs' Suсh as rеaсtion timеs, whiсh сan aссount for thе diffеrеnt oЬsеrvaЬlеphеnсltvoеs.

Bесausе of his wor pointеd as onе of thе f fоr Biology in Bеrlin in fеrеnсеs Ьеtwееn gеog raсеs only rеpгеsеntеd lutionary transformati mutations. His idеas .

phеnoсopiеs and hom phеnotypiс сhangеs.c usеd to dеsсriЬеthеsеr phors in thе history o Mayr's Sуstеmаtiсs ап part in ordеr to rеfutе сеntly in thе сontеxt tyрiс сhangеs arе oftе nеtworks of gеnеs, a r sсhmidt's еarliеr idеas found rеfugе аftеr his r

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DiеtriсhМ , . R . 2 0 0 3 .R i Gеt Nаture Rеuiеt,us G o l d s с h m i d tR, . [ 1 9 4 0 S. J. Gould. Nеw Hl 1'958.Tbeorеtiс 1'96О'1папd Оu Mayr, Е. 1942.Sуstеmа UnivеrsityРrеss.

Gould, StеphеnJa

Stеphеn Jay Gould wа сultural sеtting that n iсonoсlasm, and his lеI ColumЬia Univеrsity h Norman D. Nеwеll. F сollaЬorator, Nilеs Еll on whiсh hе would sеr In his еarly work, ( growth of individuals r Using quantitativе mс portion of individual < гatеs and timing оf tht powеrful tool for ana еxtinсt organisms.Mo providе a potеntial ml

Gould that whiсh is diffiсult to ar. l s е е kt o е x p r е s st h е е l u s i v е

Juyеr' еd. СamЬriсlgе: /e. Сhiсago: Univеrsity of of Sсiепсе:А Phепсltltепologу Prеss' 'tural invеstigatiсlnsаr-rd ,)mpdпia|1 to G сlеthе,',\:f.

-1es8) rtrovеrsial gеnеtiсists of thе rtаlisa t n d а с r е а t i v сr h е o r i s t , llе of systеmiсmutаtions (or ution hаvе bееn сonsidеrеd ystallizеthе so-саllеdmodеrn l е a s t ,u n i t е di n t h е i г o p p o s i r y G o u l d ( 1 9 8 2 .i n h i s i n t r o :еriаl Bаsis of Еuoltttion) and }оldsсhmidtand arguеd that 1 as thе prеvailing dogma of ankfurt am Main into zrprowеll-to.dо miliеu. Hе Ьеgan ding lесttrrеs of lroth otto I intеrеstwas zoology' and in d Hеrtwig. His first aсadеmiс niсh. As part of his tеaсhing 'tivе anatomy, whiсh in part logy, anatomy' and сеll Ьiolms of gеnеtiсs and суtolоgу, rr. Goldsсhmidt workеd with саl variants, whеn nratеd to d intеrmеdiatеintеrsехеs.To nidt proposеd a dynamiс and эn thе undеrlying physiologigsiologiсalgеnеtiсs.Thе Ьasiс nt variants of gеnе pгoduсts suсh as rеaсtion timеs, whiсh :ypеs.

Bесausе of his work in gеnеtiсs and physiology, Goldsсhmidt was appointеd as onе of thе founding dirесtors of thе nеw Kaiser \Wilhеlm Institute for Biology in Bеrlin io \91З' Soon his intеrеstsаlso inсludеd thе gеnеtiс dif' tЪrеnсеsЬеtwееn gеographiс гaсеs of Lуmапtriа. Thеsе diffеrеnсеs Ьеtwееn raсеs only rеPrеsепtеd miсroеvolutionary еvеllts. To aссount foг lаrgеr еvolutionary transformations, Goldsсhmidt postulated thе ехistеnсе of maсromutations. His idеаs on this suЬjесt wеrе also motivatеd Ьy his study of phеnoсopiеsand homеotiс mutations, Ьoth геprеsеntinglargе сoordinatеd phеnotypiс сhangеs. Goldsсhmidt's notion of ..hopеful monstеrs''' whiсh hе usеd to dеsсriЬе thеsе rrovеl phеnotypеs' is onе of thе most unfortunatе mеtaphors in thе histoгy of biology and was soon ridiсulеd Ьy his сritiсs. Еrnst Ма1.r's Sуstemаtics апd the Оrigiп of Speсiеs (|942) was writtеn in major pаrt in ordеr to rеfutе Goldsсhmidt. Howеvеr, as wе havе lеaгnеd morе rе. сеntly in thе сontехt of еvolutionary dеvеlopmеntal Ьiology, largе phеnorypiс сhangеs arе oftеn thе rеsult of еvolutionаry сhangеs in thе rеgulatory nеtworks of gеnеs, а сonсеpt that is, at lеast in spirit, vеry сlosе to Goldsсhmidt'sеаrliеr idеas. Gоldsсhmidt diеd in 1958 in Bеrkеlеy, whеге hе had found rеfugе aftеr his еmigration from Nazi Gеrmany. B|вLIoGRAPHY monstеrsand othеr..hеrеsiеs.'' Diеtriсh,M. R. 200]. RiсhardGсlldsсhmidг: Hoреfr"rl Nаturе RеuiешsGеtlеtiсs4: 68_74. Gсlldsсhmidt, R. [1940]1982.The МаteriаlBаsisof Еuolиtioп.Introduсtioп Ьy S. J. Gould. Nеw Hаvеn,СT: Yalе UnivеrsityPrеss. 1958. ThеorеtiсаlGепеtiсs.Sеаttlе:Univеrsiтyof WashingtonРrеss. .Washington 196О.Iп апd Оttt of thе Iuorу Triшеr.Seatt|е: Univеrsityof Рrеss. Мayr, Е. 1942.Sуstеmаtiсsапd thе origin of Spесiеs.Nеw York: СolumЬia Univеrsity Prеss.

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Gould, Stеphеnlaу $94|_2002) StеphеnJay Gould was Ьorn аnd raisеd in Nеw York Сity, in a fanrily and сultural sеtting that nurturеd his intеrеst itr natural history' his instiпсrivе iсonoсlasm,and his lеft-lеaningpolitiсs. Hе attеndеdAntioсh Сo1lеgе,аnd at СolumЬia Univеrsity hе еarnеd his PhD undеr thе dirесtion of palеontologist Norman D. Nеwеll. Hе also Ьесamе assoсiatеdwith his lifеlong fгiеnd and сollaЬorator' Nilеs Еldrеdgе. Harvard сallеd, and Gould joinеd thе faсultу on whiсh hе would sеrvе throughout his сarееr. In his еarly work, Gould foсusеd on сЬangеs in shapе that oссuг in thе growth of individu:rlsаnd in thе еvolution of animal spесiеsand highеr taxa. Using quantitativе mеthods оf allomеtry, Ье showеd how сhangеs in proportion of individual сharaсtеrs' in rеlation to Ьody sizе, rеflесt shifts in thе ratеsand timing of thеir dеvеlopmеnt (sееGould |966). This provеd to Ье a powеrful tool fоr analysis of adaptivе funсtion аnd pattеrns of еvolution in ехtinсt organisms.Morеovеr, thеsе shifts in timing' known as hеtеroсhrony, providе a potеntial mесhanism for rapid еvolutionаry сhangе, triggеrеd Ьy

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Gould modеst сhangеs in rеgulatory gеnеs. Io Опtogепу апd Phуlogепу fl977Ь\, Gould assеssеdthе history of thе study of hеtеroсhrony and showеd how it was rеlаtеd to an еmегging fiеld that would sotln Ьесomе known as еvoiutionary dеvеlopmеntalЬiology, now niсknamеd еvo-dеvo. Studiеs of triloЬitеs and land snails providеd Еldrеdgе and Gould with еvidеnсе showing that spесiеs pеrsist for long pеriods of timе with littlе if any dirесtional сhangе. Нowеvеr, еvolution сan oссur rapidly in loсally isolatеd populations, giving risе tо nеw spесiеsthat may sееm from thе fossil reссlrd to havе appеarеd instantanеously.Еldrеdgе and Gould (1972) advoсatеd a modеl of ..punсtuatеdеquiliЬrium'' as an аltеrnativеto grаdualism, that was impliсit in most сonvеntionаl ассounts of еvolution Ьy natural sеlесtion (sее also Gould and Еldrеdge 1977,199зI. This hypothеsispromptеd a livеly сontrovеrsy that was nеvеr fully rеsolvеd;Ьoth pattеrnsof сhangе сan Ье shown to oссur. Мany palеоrrtologiststеndеd to favor punсtuаtеd еquiliЬrium, whеrеas most gеnеtiсistshеld to gradualism, Ьoth groups swayеd Ьy thе nаturе of thеir data and thе timеsсalеsovеr whiсh it is oЬsеrvеd.(StеЬЬinsand Ayala 1981 providеs gеnеtiсists,rеsp()nsеto plrnсtuatеdеquiliЬrium. A historiсal ovеrviеw of thе сontrovеrsyсan Ье found in Sеpkoski аnd Rusе 200s.) Gould alwаys еmphasizеd thе rolе of historiсal сirсumstanсеin еvolution. In ..Тhе Spandrеlsof San Marссl and thе PаnglossiаnParаdigm:A Сritiquе of thе Adaptationist Programmе'' (1979), сoauthorеd with RiсhаrrdLеwоntin, Gould сhallеngеd thе notion that еvеry aspесt of fоrm and Ьеhavior of living organisms сan Ье ехplainеd dirесtly in tеrms of nаtural sеlесtion. Naturаl Ьarriеrs or сonstraints of anсеstral dеsign and pathways of dеvеlopmеnt' сharaсtеrs with no immеdiаtе adaptivе funсtion that еmеrgе aS Ьy-produсts of sеlесtion for othеr fеaturеs,and aЬсlvеall сhanсе must Ье takеn into aссount. (Sеlzеr 799З analуzеs this papеr frсlm a litеrary pеrspесtivе.)Rеlatеdly, Gould was a lifеlong еnthusiastfor thе idеasof thе Sсottishmorphologist D'Arсy N7еntworthThompson, who always arguеd that rтuсlr animal form сould Ье еxplainеd as thе rеsult of thе laws of physiсs and сhеmistry without rеfеrеnсеto natural sеlесtion(sееGould \971\' Gould was a vigorous opponеnt of thе сonсеpt оf еvolutionary ..prсrgrеss.'' To him, it impliеd a prеdеtеrminеddirесtion that has no Ьаsis in prinсiplе сlг on thе еvidеnсеof lifе's еvсllutionaryhistory. Сhangе is unprеdiсtaЬlе.Мany faсtors influеnсе thе fаtеs of individual spесiеs, lеаd to divеrsifiсation of major groups of organisms' or саusе mаss ехtinсtions tl-rathavе pеriodiсally сlеarеd thе stagе, making way for thе еvolution of nеw сasts Of сharaсtеrs from a fеw survivors. Gould (198s) is aпrong thе sеvеral papеrs that taсklе progrеss. Full Housе: Тhе Spreаd of Ехсеllепсe from Plаtсl tсl Dаrшiп (7996) is full-lеngth disсussiorrdirесtеd at thе gеnеral rеadеr as muсh as аt thе profеssional еvolutiontst. Building on thе сOnсеpt of spесiеs sеlесtion еlaЬoratеd Ьy StеvеrrStanlеy (1975,1979)' Gould arguеd that pattеrnsof еvolution in сladеs (groupsof rеlatеd spесiеsthat sharе a сommon anсеstor)arisе from a proсеss of sеlесtion diffеrеnt in kind from that whiсh оссurs in еvolutiсlnat thе lеvеl of popula. tions and spесiаtion. If this maсroеvoluti
A partiсularhеro of St .Wеntworth Thomрsor апd Form, shtlwingho iеllyfish(B) h:rvеthе sа paraffir.r(A), wеnt fаr t nесеssarilyеvеnthс pr ..ordеrftlr f сhristеnеd 1 8 5 ) .T h е r еi s s o m еа n thе сlaim is thаt phеnс adaptivеnor nonadаp arе adaptivеЬut thаt s

еvolutionary сhangеl rесt еffесts of naturаl posе an ехpandеd еv сritеria opеratеsаt su tion is a foсus of сurr tion opеratеsamong (

Could ttogе|1у ilпd Phуlogепу fl977Ь), rеtеrt>сhrсlтty and shсlwеd how it j soon Ьесtlmеkn
7r).

nсеptof еvolutionarv ..progrеss.'' n that l-rtrs nсl Ьilsis in prirrсiplе or y. Сhаngе is unprеdiсtaЬlе.Мany pесiеs,lсad to dir.еrsifiсatit>nof ехtinсtiоIrstЬаt h;rvеpеriodiсally lution of nеW сasts of сharzrсtеrs )ng thе sеvеralpapеrs thаt taсklе ,псе froп Plаtсl to D,lrц',iп (1996) lral геас1сг as mtrсh аs at thе proion еlaЬ
AB A partiсulirrhеro of StеphеnJav Gould wаs thе SсottishmorphоlogistD'Аrсy WеntwortlrTlrorn;lsor-r. Illr-rsгrаti
еvolutionaryсhangе within еirсh spесiеs,it is thеrеЬy dессluplеdfrom thе dirесtеffесtsof naturаl sеlесtiot-t, aсting on pоpulations.This lеd Gould to proposе аn ехpandеd еvoltrtionаrythеorv, in whiсh sеlесtion Ьаsеd on distinсt сritеriaOpеratеsat suссеssivеlеvеls in thе taхonomiс hiеrarсhy. Spесiеssеlесtion is a foсus of сurrеnt rеsеаrсhand ехpеrimеntаltеsts.Thе idеa that sеlесtion opеrаtеsаm()ngсlаdеs has ),еtto Ье translаtес.l into tеstaЬIеhypothеsеs.

6l.l

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coиld Bесausе hе сhallеngеdprеvailing viеws, somе rightly saw Gould as a сritiс of neo-Darwinian orthodoxy. Nonеthеlеss, hе was an ardеnt admirеr of Сharlеs D:rrwin, sееinghis own work as an ехpansion of Darwin's еntеrprisе and Ьу no l-nеаnsa rеfutation of it. Gould's еarliеr work is most aссеssiЬlеto thosе sееking arr intгoduсtion to lris idеas;his finаl mаgnum opus,TЬе Struсtиrе oi Еuolutioпаrу Thеor1' Q002), is a riсlr Ьut unwiеldy tomе, morе rеadr I yq u a r г i е dt h a n r е а d i n i t s е n t i r е t y . In addition to his original rеsearсh, Gould puЬlishеd numеrous еssays' most notаЬly in thе magazine Nаturаl Historу. Thеsе wеrе сollесtеd in а sеriеs of Ьеst-sеllingЬooks, starting with Еuer siпce Dаrш,in (1977a). Othеr works addrеssеd mеаsllrеsof human brаirr sizе and intеlligеnсе(Gould 1981)' thе Ьizarrе ехtinсt irnimals of CamЬгian sеas (Gould 1'989|,and thе rеlation Ьеrwееn sсiеnсе and геligion (Gould 1999|. Hе tеstifiеd as an еxpеrt witnеss iп thе Arkan..сrеаtion sas сourt сasе whеrе sсiеnсе'' was shown to Ье a rеligious doсtrinе. Gould nеvеr hеsitatеdto join an intеllесtual fight. As a result, Gould Ьесamеthе prеmiеr puЬliс faсе of еvolution in thе Unitеd Statеs during thе last quаrtеr of thе rwеntiеth сеntrrry. BIBLIOGRAPHY .'J7. D., P. Н. Kеllеy, аnd R. М. Rсlss,еds.2О08' StephепJау Gсluld:RеflесAllmоn' tiсlпsсltt His Vieш of l-ifе. Nеrv York: Oxford UnivеrsityPrеss. An altеrnativе to phylеtiс Еldrеdgе,N., аnd S. J. Gould. 1972.PunсtuatеdеquiliЬri:r: graduаlisrrr. In T. J. М. Sсhopf,еd.'МodеIsiп Pаlеobiсllrlgy, 82-115. Frееmirn'Сoopеrаnd Сo. Sаrll-гallсisсo: Gould, S. J' 1966.Allomеtryand sizеin ontogеnyirndphylogеnу'Bkllogiсаl Rеuiеtl,sof the СаmbridgеPhilosсlphiсаlSoсietу41'z587-640. 1971. D'Arсy Thompson and thе sсiеnсеof forrn.Nelu Litеrаrу Нistorу 2: 229-258. 1977,.l.Еuer siпсе Dаrьuitt.Nеw York: Nсlrton. 1977Ь.Опtogепуапd Phуlсlgеп1,. СamЬridgе'МA: Нarvard UnivегsitуРrеss. 1981.TbеМisпtсаsнrе of Маn. Nеw York: Nrrrton. 1988.on rеplасingthе idеaof progrеsswitlr an opеrationalnotionof Progress,319-338' In М. H. Nitесki, ed.,Еuolutiсlпаrу Сhiсago: dirесtionality. Univеrsityof СhiсаgoPrеss. 1989. WопderfulLifе: Тhе BurgеssShаlеапd thе Nаturе of Historl' Nеw York: Norton. |996, FilI Housе: Thе Spreаdсlf Ехсеllепсеfrtlm PIаtoto Dаrtuiп. Nеw York: Раr.rgоn. |999. Rtlcksof Аgеs:Sciеnсеапd Religioп iп tbе Fullпessof Lifе. Nеw Yoтk:Ballantiпе. 2002' Thе Strисtureсlf ЕuolиtioпаrуThеorу.СamЬridgе,MA: Harvard UnivеrsityI)rеss. Gould, S. J., аnd N. Еldrеdgе.1977, Punсtuatеd еquiliЬria:Thе tепrpoаnd rrrodеof еvolцtionrесonsidеrеd. Pаlесlbiсllсlgу 3: 115_151. 1993.Pr-rnсtuatеd еquilibrir"rm сotnеsof agе.Nаturе З66 Z2.3-Z27. Тhе spandгеls of San Маrсo and thе Gould, S. J., and R. С. Lец,сlrrtiл.7979. pаradigm:А сгitiqtrеof thе adaptationist programme,Proсeеdiпgs Panglossiаn of thе Rоуаl Soсiеtуof Lсlndrlп'SеriеsB 205:581-598. SсiепtфсProse.Мaсlison:Univеrsiryof wisсonsin Sеlzеr,.J.,еd. 1993. Uпdеrstапdiпg Prеss.

Sеpkoski, D., and М. I Univеrsity of Сhiс Stanlеy, s. М. 1975. A Nаtiспаl Aсаdem, |979. Масrсlе StеЬbins, G. L.' and F' Sсiеnce 21'3:967_

Grant, B. Rosеп and Grant, Pеtе

Rosепlary and Pеtеr win's finсhеs in thе ( formеd onе of thе dеsсriЬing thе fееdin populations; doсum( tеrns of mаtе сhoiсе struсtillg thе phylog thе signal сasе study Thе Grants rесеiv with honors from I Ьridgе. Thеy mеt an lumЬia. P.R.G' tool СolumЬia; B'R.G. tс doсtoral yеar at Yal( Univеrsity of Miсhig positions at thеsеun island Ьiгd populati goеs and morphоlog diffеrеnt islands.B.R among individuals iп еaгly pаpеrs on sеlе patriс spесiation. Th thеm to thе Galipag сhallеngеsof logistiс Thе Grants havе r сluding the Darwin, and tlrе Darwin-.Wа Grants wеrе еlесtеd thеy wеrе Ьoth еlесt 2007, P.R.G. in 200 S с i е n с е s( B . R . G . i n 2 BIвLIoGRAPl

Grant,B. R., and P. R. Populаtion:Тhе L СhiсаgoPrеss.

Grапt аnd Grапt

somе rightly saw Gould as a сritiс ss, hе was an ardеnt admirеr of r ехpansion of Darwin's еntеrprisе s еarliеrwork is most aссеssiЬlеto his final magnum opls, Tbе Struciсh Ьut unwiеldy tomе, morе rеadd puЬlishеdnumеrous еssays' most Thеsе wеrе сollесtеd in a sеriеs of Dаrшiп (\977a|. Othеr works adrtеlligеnсе(Gould 1981), thе bizarrе p$9),аnd thе rеlation Ьеtwееn sсil as an еxpеrt witnеss in thе Arkants shown to Ье a rеligious doсtrinе. fight.As a rеsult, Gould Ьесamе thе геdStatеsduring thе last quartеr of

эds.2008. StеphепJау could: Rе|lес.ord Univеrsity Prеss. ld еquiliЬria: An altеrnativе to phylеtiс ls iп PаIеobiologу, 82-II5. еny and phylogеny. Biologiсаl ioсietу 41: 587_640. rсе of form. Netu Literаrу Historу 2: Norton. Ьridgе,МA: Harvard Univеrsity Prеss. 1сlrk:Norton. ;s with an opеrational notion of utioпаrу Progrеss, 3 1 9_33 8. Сhiсago: аle апd the Nаtиrе of Historу. llепсе[rom Plаto ttl Dаrшin. gioп iп tЬе Fullnеss of Lifе. Гhеorу. СamЬridgе, МA: Наrvard :d еquilibriа:Thе tеmpo and modе of l5-151. i age.Nаturе 366: 223_227. эаndrеlsof San Marсо and thе dаptationistprogrammе. Proсееdings 205:581-598. .Wisсonsin -lse.Madison: Univеrsiry of

Sеpkoski, D.' and М. Rusе, еds. 2008. Thе Pаleobiolсlgiсаl Rеuolutioп. СЬtсago Univеrsity of Chiсago Prеss. Stanlеy,S. М. 1975. A thеory of еvolutiоn aЬovе thе spесiеs |еvе|.Proсееdiпgs of thе Nаtioпаl Acаdеmу of Sciепсеs 72: 646-65О. 1979. Масroеuolutioп, Pаttеrп апd Proсеss. San Frаnсisсo: W. Н. Frееman. Stеbbins,G. L.' and F. J. Ayala. 1981. Is а nеw еvolutionary synthеsisnесеssary?

Sсiепcе2I3: 967_971'.

-R.D.к.Т.

Grant,B. Rosеmary(b. t936)' and Grant, PеtеrR. (b. 19з6) Rоsеmary and Pеtеr Grant arе rеnownеd for thеir long-tеrm studiеs of Darwin's finсhеs in thе Gal6pagos Islands. Thеy and thеir сollaЬorators havе pеrformеd onе of thе most сomprеhеnsivе studiеs of any group of spесiеs, dеsсriЬingthе fееding есology, Ьrееding Ьiology, and numеriсal dynamiсs of populations;doсumеnting natural sеlесtionon morphologiсal traits and pattеrns of matе сhoiсе; disсovеring hyЬridization Ьеtwееn spесiеs; and rесonstruсtingthе phylogеnеtiс rеlationships among thеm. Thеir work stands as thе signal сasе study of еvolutionary Ьiology. Thе Grants rесеivеd undеrgraduatе dеgrееs in 7960, Rosеmary (B.R.G.) with honors from ЕdinЬurgh and Pеtег (P.R.G.) with honors from Сambridgе. Thеy mеt and marriеd whilе аttеnding thе Univеrsity of British Сolumbia. P.R.G. took his doсtoratе jn 1964 from thе Univеrsity of British СolumЬia; B.R.G. took hеrs in 1985 from Uppsala Univеrsity. Aftеr a postdoсtoral yеar at Yalе, P.R.G. hеld faсulty positions at MсGill Univеrsity, thе Univеrsity of tr4iсhigan' and Prinсеton Univеrsity whilе B.R.G. hеld rеsеarсh positions аt thеsе univегsitiеs.P.R.G.'s еarly work foсusеd on thе есology of island Ьird populations, inсluding pattеrns of distriЬution aсross arсhipеlagoеs and morphоlogiсal variation аmong spесiеsand among populations on diffеrеnt islands. B.\G.'s еarly work on Darwin's finсhеs еxaminеd variation amоng individuals in bill morphology and song сharaсtеristiсs'lеading to hеr еarly papеrs on sеlесtion on Ьill morphology and thе possiЬilitiеs for sympatriс spесiation. Thе Grants' сommitmеnt to studying Darwin's finсhеs took thеm to thе Gal6pagos for six months of еvеry yеar (sinсе 197З), dеspitе thе сhallеngеsof logistiсs' limitеd diеt, and thе spartan lifеstylе of living in tеnts. Thе Grants havе rесеivеd а host of honors, individually and togеthеr, inсluding thе Darwin Меdal of thе Royal Soсiеty of London, thе Balzan Prizе' and thе Darwin-!Иallaсе Award of thе Linnеan Soсiеty of London. Both Grants wеrе еlесtеd to thе Amеriсan Aсadеmy of Arts and Sсiеnсеs in 1997 thеy wеrе Ьoth еlесtеdas Fеllows of thе Royal Soсiеty of London (B.R.G. in 2007, P.R.G. in 2003) and forеign mеmЬеrs of thе U.S. National Aсadеmy of S с i е n с е s( B . R . G . i n 2 0 0 8 , Р . R . G . i n 2 0 0 7 \ . в|вLIoGRAPнY Grant,B. R., and P. R. Grant. \989. ЕuolиtioпаrуDупаmiсsof а Nаtиrаl Populаtioп:Thе Lаrge СасttlsFinсh of the Gаldpаgos.Сhiсago:Univеrsityof СhiсagoPrеss.

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Crаnt Grant, P. R. 1986. Есologу апd Еuolutklп сlf Dаrtuiп's FiпсЬеs. Prtnсеton, NJ: Prinсеton Univеrsity Prеss. Grant' P. R., and B. R. Grаnt. 2ОО7. I]oш апd Whу Spесies Мultiplу: Tbе Rаdiаtion -].Т. of Dаrtuiп's Fiпсhеs, Prinсеton, NJ: Prinсеton Univеrsity Prеss.

Grant, Robеrt Еdmond (Т793_1874) Robеrt Еdmond Grant' an ЕdinЬurgh-Ьorn spongе еxpеrt, ir-rtroduсеdсomparativе anatomy to Britain in thе 1820s and 18З0s. Hе inсоrporatеd thе studiеs of Jеan.BaptistеLamaгсk and Еtiеnnе Gеoffroy Saint-Hilairе' aссеpting thе ..transformism,''or еvolution, aссompanying thеir works. Grant also induсtеd thе young Сharlеs Darwin into Lamarсk's viеws. Darwin, Ьorеd Ьy mеdiсinе at ЕdinЬurgh Univеrsity ln 1825-1827, studiеd Noгth Sеa invеrtеЬratеs with Grant, who had Ьесomе an MD in 1814. As an old man writing Ьls Autobiogrаphу, Darwin rесallеd Grant's admiration for Lamarсk. Grant сhampionеd Hеnri dе Blаinvillе's сontinuous сhаin of lifе (rathеr than Gеorgеs Сuvier's disсrеtе embrаnchemeпts) and Gеoffroy's Ьеliеf that thе samе organs oссцrrеd throughоut thе сhain-hеnсе Grant's сlaim in 1825 to havе found thе homology of thе vеrtеЬratе's panсrеas in mollusks. Studying spongеs in 1825-1828, Grant сoinеd thе group's namе, Porifеra, and hе mootеd a simplе, dеfеnsеlеss,frеshwatеr form as thе ..parеnt'' of thе armorеd marinе spесiеs. Darwin еxaminеd thе larvaе of thе lсlсal Ьryozoan Flиstrа undеr Grant. Grant Ьеliеvеd thеsе lаrvaе wеrе rеlatеd to thе ,.ova'' of algaе and pointеd Ьaсk to the spontanеouslygеnеratеd..monads'' lying at thе junсtion of thе plant and animal kingdoms. At ЕdinЬurgh Darwin was alrеady Ьroaсhing issuеs surrounding thе birth of individuals and spесiеs' еvеn if hе rеjесtеd Grant's monadism upon bеginninghis own еvоlutionary spесulations. As thе first profеssor of сomparativе anatomy at London Univеrsity in 1827, Grant alеrtеd thе mеtropolitan еlite to thе Lamarсkian thrеat. Hе joinеd thе Gеologiсal Soсiеty сounсil in 1832, just as Сharlеs Lyеll was puЬlishing his antievolutionаry volumе Prinсiples of Geologу. Grant's fossil lесtures promotеd thе ..dirесtgеnеration'' of suссеssivеspесiеs,onе giving Ьirth to anothеr. And his studеntswеге ехaminеd on thе сonditiоns rеspоnsiЬlеfor ..originating and еffaсing thе tеmporary organiс film on our planеt'' (Zoo|ogy Ехamination Papеrs, 1857_58, p. 6, in ..Grant on Zoologiсal SuЬjесts,'' Сollеgе Сollесtion DG 76, Univеrsity Сollеgе London). Grant took thе Fullеrian сhair of physiсllogy at thе Royal Institution in 18З7, Ьut that markеd his apogее.Hе had lost his сounсil sеat at thе Zoo1ogiсal Soсiеty in 1835, whеn thе zoo's aristoсratiсpatrons gavе his сonsеrvativе rival, Riсhard owеn, pгеfеrеntial trеatmеnt. At thе Gеologiсal Soсiеty, Owеn сountеrеd thе fossil impliсations of Grant's transmutationism. Grant lost rеsourсеs and his finanсеs tееtеrеd.Thе 1840s found him living in a slum, his shaЬЬy swallow-tail сoat as unfashionаЬlе irs his lесturеs. A rising youllg Thomas Hеnry Huхlеy in 1852 mеrеly laughеd аt Gfant's ..ессеntriсity.'' At thе еnd, Grant еnvisаgеdplanеtary сooling as thе motor to powеr thе еvo. lution of warm-Ьloodеd mammals and Ьirds from dinosaurs and otеrosaurs.In

Tаbulаr Vieш of the P praisеd Darwin's on t| thеir ЕdinЬurgh days tс trееs sрrouting from spс two mеn diffеrеd. A sеп and fеw mournеd his pа в|BLloGRAPHY

Dеsmond,A. 1984a.RoЬ transmutationist. /Oи 1984Ь.RoЬеrtЕ. l,есturеson ..palаеo з95_413. |989' Tha Pоlitiс Rаdiсаl Loпdсlп.Сht S l o e n ,Р . R . l 9 8 5 .D r г w i In D. I transformism. N J : P r i n с е т оU nrlivе

Gray, Asa (1810-1

Asa Gray was onе of tI iсa. Hе Ьесame onе of mеnts dеrivеd from thе of еvolution. A dееply logiсal impliсations of l ural sеlесtionсould Ье Ьy a wisе and Ьеnеvolе Gray was Ьorn in Sаr i n m е d i с i n еа n d p r a с t i tеaсhing so that hе w( Fishеr Profеssor of Nat stood that hе would сo сonsult with othеr bot Amеriсan plants. Hе w ( 1 8 3 8 _ 1 8 4 3 )a n d е v е Вotапу of thе Northert January 30, 1888. Gray,s work on thе Amеriсan plants madе voсatеd Ьy Louis Agas liсation of Оп thе Оri lеttеr to Gray, datеd S Darwin and A. R..sИa 264-267|. Gray suЬsе taсks from Agassiz at t

Grау ,'rшiп'sFiпсhеs. Prinсеton' NJ: Vhу SpесiеsМltltiplу: Тhе Rаdiаtion -J.T. ln UnivеrsityPrеss.

4) spongе ехpеrt' introduсеd сom. аnd 18З0s. Hе inсorporatеd thе rе Gеoffroy Saint-Hilairе' aссеptnpanyingthеir woгks. Grant also marсk'sviеws. Darwin, Ьorеd Ьy | 8 2 7 , s t u d i е dN o r г h S е a i n v е r r е ) in l8l4. As an old man wгiting ; аdmirationfor Lamarсk. сontinuous сhain of lifе (rathеr zпts|and Gеoffrоy's Ьеliеf that thе -hеnсе Grant's сlаim in 1825 to 's panсrеasin mollusks. Studying group's namе, Porifеra' and hе ..parеnt''of thе armorеd m as thе l of thе loсal Ьryozoar' Flustrа un..ova'' of algае and rеlatеdto thе . . m t l n a d s .I.y i n ga t t h е j u n с t i o n d urgh Darwin was alrеady Ьroaсhals and spесiеs,еvеn if hе rеjесtеd еvolutionaryspесulations. n а t o m yа r L o n d o n U n i v е r s i г y i n е to thе Lamarсkian thrеat. Не 32, just as Сharlеs Lyеll was publеs of Geology. Grant's fossil lесuссеssivеspесiеs'onе giving Ьirth l on thе сonditions rеsponsiЬlе for :ganiсfilm on our planеt'' (Zoo|..Grant on Zoologiсal SuЬjесts,'' lgеLondon). o l o g y а t t h е R o y а l I n s t i t u t i o ni n ost his сounсil sеat at thе Zoolog:atiс patrоns gavе his сonsеrvativе . At thе Gеologiсal Soсiеty, Owеn ; transmutationism.Grant lost rе)s found him living in a slum, his . rising young э a s h i s | е с t u r е sA ..ессеntriсity.'' at Grant's ;hеd ling as thе motor to powеf thе еvol from dinosaurs and ptеrosaurs. In

Tаbиlаr Vieu., сlf the Primаrу Diuisioпs of tbе Апimаl Kiпgdom (1861) hе praisеd Darwin's Оп the origin of Speсiеs whilе rеminding his old pupil of thеir ЕdinЬurgh days togеthеr. But thе Таbulаr Viеш,s сountlеss еvolutionary trееssprouting from spontanеously gеnеratеdmonads showеd how dееply thе fwo mеn diffеrеd. A sеminal figurе in thе radiсal 1830s, Grant outlivеd his agе, and fеw mournеd his passingin |874' вlBLIoGRAPHY Dеsmond,A. 1984a.RсlЬеrtЕ. Grant:Thе soсialprеdiсаmеnt of a prе-Darwinian transmutationist. lournаl of thе Historу of Biologу \7: \89_223' 1984Ь.RoЬеrtЕ. Grаnt'slаtеrviеwson organiсdеvеlopmеnt: Thе Swinеy Lесturеson ..palaеozооlogy,'' 1853_1857.Аrсhiuеsof NаturаlНistorу 11 з95-4\З. 1989. Thе Politiсs of Еuolutioп:Мorphologу,Мediсiпe' апd Rеform iп Rаdiсаl Loпdoп, Сhiсago:Univеrsityof Сhiсago Prеss. Sloan,P. R. 1985.Darwin,sinvеrtеbratе Prесonditions for рrogram'1826-1.8З6: trаnsfoгmism.In D. Kоhn, еd.,Thе Dаrшiпiап Hеritаgе,71-120,Prinсеrсlп, NT: Prinсеton Univеrsitv Prеss.

-4.D.

Gray,Asa (1810-1888) Asa Gray Was onе of thе lеаding Ьotanists of mid-ninеtееnth-сеntury Amеri с а . H е Ь е с а m еo n е o f С h а r l е s D a r w i n ' s m o s r a с t i v е s u p p o г r е r s u . sing агgumеnts dеrivеd from thе gеographiс distriЬution of plants to dеfеnd thе thеory of еvolution. A dееply rеligious man, hе also wrotе еxtеnsivеly on thе thеo. logiсal impliсations of Darwinism' attеmpting to show how еvolution Ьy natural sеlесtionсould Ье rесonсilеd with thе Ьеliеf that thе world was dеsignеd Ьy a wisе and bеnеvolеntGod. Gray was Ьorn in Sauquoit, Nеw York, on NоvеmЬеr 18, 1810. Hе trainеd in mеdiсinе and praсtiсеd for a fеw yеars, Ьut aЬandonеd this for part-timе tеaсhing so that hе would havе morе timе for Ьotany. Hе was appointеd Fishеr Profеssor of Natural History аt Harvard in 1842, whеrе it was undеrstood that hе would сonсеntratеехсlusivеly on Ьotany. Hе visitеd Еuropе to сonsцlt with othеr Ьotаnists, Ьut his own work foсusеd mainly on North Amеriсan plants. Не workеd oo a Florа сlf Nortb Ameriса with John Torrеy (1838_1843) and еvеntually produсеd a highly suссеssful Мапuаl of the Botсlпу of tbe Northеrп Uпitеd Stаtеs (7848). Hе rеtirеd tn 187З and died on J a n u a r y3 0 , 1 8 8 8 . Gray's wсlrk on thе сlassifiсation and gеographiс distriЬution of North Amеriсan plants madе him suspiсious of thе ..сrеationist''position bеing advoсatеd by Louis Agаssiz. Сharlеs Darwin сonfidеd in Gray Ьеforе thе puЬliсation of oп tbe Оrigin of Speсiеs in 1859, and an aЬstraсt of Darwin's lеttеr to Grаy' datеd SеptemЬеr5, 1857, formеd part of thе joint papеr Ьy Darwin and A. R. rJИallaсеin 1858 (rеprintеd in Darwin and !7al1aсе1958, 264_267). Gray suЬsеquеntlydеfеndеd thе thеory of еvolution against attaсks from Agassiz at thе Amеriсan Aсadеmy of Arts аnd Sсiеnсеs.

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Group Sеlесtioп Sеvеral of his pаpеrs, supporting еvolutionisrnOl1thе Ьаsis of Ьotaniсal gеography, wеrе сollесtеd in his Dаrшiпiапа (I876). Gray saw how thе dispеrsal of plants from an оriginаl loсation' сouplеd with adaptation сlf populаtions to thе loсal еnvironmеnts fоund in thеir nеw homеs, сould aссount for thе obsеrvеd distriЬutiorrof spесiеs.Thе similarity Ьеtwееnthе plants of еastеrn North Amеriсa and Jаpаn сould Ье ехplainеd Ьy noting that in еaгliеr gеologiсal timеs, thеsеplants lrаd Ьееn widеsprеad aсross Asiа and North Amеriсa Ьut had Ьееn сlrivеrrsollthward during thе iсе сtgеs,r,l,ithonly thе two isolatеd fragmеnts of thе еarliеr population now rеmaining. As a staunсh PrеsЬytеrian,Gray was anхious to show that Dаrwin's thеor1' did not dеstroy thе Aгgumеnt from Dеsign. In arsеriеsсlf artiсlеs (геprintеdin Dаrшiпiапа) hе Ьеgаn by arguing that аny proсеss Ьy whiсh spесiеs соuld bе adaptеd to thеir еnvironmеnt Was сompatiЬlе with thе Ьеliеf that thе еvolutionary proсеss had Ьееn еstaЬlishеdЬy a wisе and ЬеnеvolеntСrеator. Latеr on' howеvеr, hе соnсеdеd that thе wastеfulnеssand сruеlty of natural sеlесtiongеnеratеddiffiсultiеsfor this approaсh, аnd hе suggеstеdthаt vаriation is lеd along Ьеnеfiсiallinеs Ьy thе Сrеatoг. Dаrrvin oЬjесtеdto this viеw bесausеit lеft Gгay supporting thе pсlsitionof thеistiс еvolr'rtiorrism, in whiсh thе diгесtion of dеvеlоorrrеntis dеtеrminеdЬv surlеrnatuгalrathеr thаn паttlral mеans. вlвLIoGRAPHY. Darwin, C. R.' аnd A. R. !7allaсе.19.'8.Еuolutioпbу NаturаISеlеctioп, Сambridgе:СamЬridgеUnivеrsityPrеss. Duprее,A. H. 1959. Аsа Grау. СamЬridgе,МA: HarvаrdUnivеrsityPrеss. Gray, A. 1'848,Мапutll of thе Botапу of thе Northеrп UrtitеdS/a/es.Bostоn: J. Munroе. 1876. Dаrшiпiапtt:Еssауsапd RеuiеtusPеrtаiпiпgttl Dаrшiпism.New York: Applеton. ) vсlls.Nеw York: Torrеy,J., and A. Gray. l8З8.l84з. А Florа сlf Nс'lrthАпlеrit'',t. .Wilеy -P'I .B. аnd РLltnап-l.

Group sеlесtion Charlеs Darwin idеntifiеd a fundamеntаl proЬlеm with soсial lifе and its potеntial solution in thе following famous passagе from The Desсепt of Мап (Darwin 1871, |66):..It must not Ье forgottеn that although a high standard of morality givеs but :l slight or no advantagеto еaсh individual mаn аnd his сhildrеn ovеr оthег mеn of thе samе triЬе, yеt thаt аrr inсrеasеin thе numЬеr of wеll-еndowеd mеn аnd advanсеmеntin thе standarсlof rrroralitywill сеr_ tainly givе an immеnsе zrdvzrrrtаgе to onе triЬе оvеr anothеr.'' This problеm and its potеntial solutiorr Ьесarте thе Ьasis of a thеorеtiсаl framеwork in еvolutionary Ьiology сallеd multilеvеl sеlесtiсrn(SoЬеrand \Wilson 1998). Bесausе nаtural sеlесtion is Ьasеd on геletivе fitnеss,a trait that Ьеnеfitsthе group as a wholе doеs not сhаngе in frеquеnсywithin thе group. A trait that Ьеnеfits ()thеrsat thе ехpеnsе of thе sеlf ilсtually dесrеasеsin frеquеnсy within thе group and will ultimatеly Ьесomе еxtinсt in thе aЬsеnсеof

othеr еvolutioni.rгy foгс quotеd aЬovе. Fсlrtunat сontriЬutе morе to thе t in thе sесond part of D group'' сan еvolvе Ьv t among groups in a lar among individцals rvitlr I t i s i m p o s s i Ь l еt o d . dеsсriЬing its trrrЬtrlеn twеntiеth сеntuг}.did n

tions straightforwardly gеnеs to есosystеms.T and was widеly сritiсiz his Ьook Аdаptаtioп аr сlassiс. lWilliams affirm i с аI f r a m е w о r k , . r g r е еvоlvе only by a рr()сс еmpiriсalсlaim thаt Ье parеd to lvitlrin-grormultilеvеl sеlесtionthес сamе thе сonsеnsusfor tionary thеoriеs оf s altruism, gаmе tЬеory' altеrnativеs to group s(

Thе 1960s сonsеllsu sеlесtion is thеorеtiсаl ramеtеr valuеs to prеv vinсing еmpiriсal еr.iсl а s а l t е г n а t i r . еdso r l t l гi l argumеnts Ьеg;rnto bе .

diffiсult to аrrguеill favс thеorеtiсal modеls of g .s7illiams himsе сеssors. traits suсh as sеx rаtio Nеssе 1991). All еr,olu istеnсе of multiрlе gгсl

idеntifiеd, сoopеriltivе within thе grtlups irrrс еnvisionеd Ьy multilеr' A mаjor еvеnt in еv сovеry that tЬе singlес gulis 1970; Nlir,vrlаrdl only Ьy small mrrtаtio spесiеssymЬiоtiс аsьос l е v е l o r g e n i s m si n r h е i сallеd, havе сlссuгrесlrt

Group Sеlесtion 619 )nismon thе Ьasis of Ьotaniсal gеl876). Graу saw how thе dispеrsal d with adaptation of populations еw homеs,сould aссount for thе LrityЬеtwееnthе plants of еastеrn nеd Ьy noting that in еarliеr gеo:еadaсrossAsia and North Amеrg thе iсе agеs, with only thе two r nоw rеmaining. ious to show that Darwin's thеoгy In a sеriеsof аrtiсlеs (rеprintеd in y proсеssЬy whiсh spесiеs сould npatiЬlе with thе Ьеliеf thаt thе Ьy a wisе аnd ЬеnеvolеntCrеator. .astеfulnеss and сruеlty of natural oaсh, and hе suggеstеdthat variattoг.Darwin oЬjесtеdto this viеw of thеistiсеvolutionism, in whiсh Ьy supеrnaturalrathеr thаn natu-

tioп bу Nаturаl Sеlесtil,lп. \: Hаrvard UnivегsityPrеss. tthеrп Uпitеd S,a,es. Bosron: ; Pеrtаiпiпg to Dаrшiпism. New . North Amеriса. 2 уo|s. Nеw York:

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,roЬlеmwith soсial lifе and its poassagеfrom Thе Dеscеnt of Мап ttеn that although a high stаndard tgеto еaсh individual man and his yеt that an inсrеasеin thе numЬеr thе standardof morаlity will сеr:iЬеovеr anothеr.'' Ьесamеthе Ьasis of a thеorеtiсal :rultilеvеlsеlесtion (SoЬеr and \WiIsеd on rеlativеfitnеss' a trait that ngеin frеquеnсy within thе group. lf thе sеlf aсtually dесrеasеsin frеv Ьесomеехtinсt in thе aЬsеnсе of

othеr еvolutionary foгсеs. This dеsсriЬеsthе first pаrt of Darwin's passagе quotеdaЬovе. Fortunatеly, groups of individuals who Ьеnеfit еaсh othеr will сontriЬutеmorе to thе total gеnе pool than more sеlfishgroups' as dеsсriЬеd ..for thе good of thе in thе seсond part of Darwin's passagе.Traits that arе group'' сan еvolvе Ьy naturаl sеlесtion, Ьut only Ьy a proсеss of sеlесtion among groups in a largеr population and oftеn in opposition to sеlесtion among individuаls within singlе groups. It is impossiЬlе to dеsсriЬе thе с()nсеpt of group sеlесtion without also dеsсriЬingits turЬulеnt history. Мany Ьiologists during thе first half of thе twеntiеthсеntury did not sharе Darwin's insight; thеy assumеd that adaptations straightforwardly еvolvе ell lеvеls of thе Ьiologiсal hiеrarсhy, fгom gеnеsto есosystеms.This position Ьесamе known аs naТvеgroup sеlесtion and was widеly сritiсizеd in thе 1960s, еspесially Ьy Gеorgе С. Williams in his Ьook Аdаptаtioп апd Nаturаl Selесtiсlп(I966), whiсh Ьесamе a modеrn сlаssiс.Williams affirmеd thе importanсе of multilеvеl sеlесtionаs a thеorеtiсal framеwork, agrееing with Dаrwin that group.lеvеl adaptations сan еvolvеonly Ьy a proсеss of Ьеtwееn-groupsеlесtion.Williams thеn madе thе еmpiriсalсlaim that Ьеtwееn-groupsеlесtionis almost invariaЬly wеak сomparеd to within-group sеlесtion. It was this еmpiriсаl сlaim that turnеd ..thе thеory of individual sеlесtion,'' whiсh bеmultilеvеl sеlесtion thеory intсr сamе thе сonsеnsusfor thе rеst of the twеntiеth сеntury. SuЬsеquеntеvolutionary thеoriеs of soсial Ьеhavioг, suсh as kin sеlесtion, rесiproсal altruism, gamе thеory' аnd sеlfish gеnе thеory, wеrе dеvеlopеd ехpliсitly as altеrnativеsto grOup sеlесtion. Thе 1960s сonsеnsuswas Ьasеd upon thrее argumеnts:(1) Ьеtwееn-group sеlесtionis thеorеtiсallyimplausiЬlе, rеquiring a dеliсatе сombination of paramеtеrvaluеs to prеvail against within-group sеlесtion;(2) thеrе is no сonvinсing еmpiriсal еvidеnсеfor group sеlесtion;and (3) thе thеoriеs proposеd as altеrnativеs do not invokе multilеvеl sеlесtion in thеir own right. All thrее argumеntsЬеganto Ье quеstionеd,еvеn as еarly as thе 1970s, although it was diffiсult to arguе in favor of a topiс that for many had Ьесomе taЬoo. Modеrn thеorеtiсal modеls of group sеlесtion arе fаr morе plausiЬlе than thеir prеdесеssors.Williams himsеlf aсknowlеdgеdthе importanсе of group sеlесtionfor traits suсh аs sеx ratio and disеasе virulеnсе (.!Иilliams 1'992: Wll'Liams and Nеssе 1991). All еvolutionarythеoriеsof soсial Ьеhavior must assumеthе ехistеnсесlf multiplе groups to Ье Ьiologiсally rеalistiс.!Иhеn thеsе groups arе idеntifiеd, сoсlpеrativе аnd altruistiс traits arе sеlесtivеly disadvantagеous within thе groups and rеquirе Ьеtwееn-grсlupsеlесtion to еvolvе, as always еnvisionеdЬy multilеvеl sеlесtionthеory (SoЬеrand.Wilson 1998). A major еvеnt in еvolutionary thеory oссurгеd in thе 1970s with thе disсovеry that thе singlе organisms of todаy wеrе thе groups of past agеs (Margulis 1970; Мaynard Smith and Szathmary 1995)' Еvolution proсееds not only Ьy small mutational сhangе,Ьut also Ьy singlе.spесiеsgroups and multi. spесiеssymЬiotiс assoсiations Ьесoming so intеgratеd that thеy Ьесomе highеrlеvеl organisms in thеir own right. Thеsе major transitiсlns of lifе, as thеy arе сallеd,havе oссurrеd геpеаtеdlyand possiЬly inсludе thе origin of lifе itsеlf as

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Grrlt,tpSeleсtiolt groups of сoopеrativе molесular rеaсtions. Dеspitе multilеvеl sеlесtion thеory's turЬulеnt past' it is thе aссеptеd framеwork for studying major transitions. Thе Ьalanсе bеtwееnlеvels of sеlесtionis not stаtiс Ьut сan itsеlf еvolvе. A mаjor transition oссurs whеn sеlесtion within groups is supprеssеd,еnаЬling Ьetwееn-group sеlесtion to Ьесomе thе primirry еvolutionaгy forсе. Tlrе paradigm of rnajor transitions did not appеar until thе 1970s and was not gеnеralizеd until thе 1990s, Ьut i.rlrеadyit sееms likеly to ехplain thе еvolution of soсial insесt сoloniеs (.Wilsorrand Hбlldoblеr 2005) and humans as thе first ultrasoсial prirnаtе spесiеs (Boehm 1999). Thе traits assoсiatеd with human morality аPpеar dеsignеd to suppress sеlесtion within groups' similar to gеnеtiс mесhanisms suсh as сhroп-losomеsand thе rulеs of mеiosis, еnabling sеlесtion among grollps to Ьесomе thе primary еvolutionary forсе. Сultural proсеssеsсan сausе groups to Ьесomе vеry diffеrеnt in thеir phеnotypiс propеrtiеs,еvеn whеn thеv arе gеnеtiсаllysirnilar.Multilеvеl sеlесtionhirs Ьесomе thе aссеptеd framеwork for thе study of human сultuгal еvolution, in еxaсtly thе samе way as thе study of major transitions (Riсhегsоn and Boyd 2004). Thе rеvival of groшp sеlесtion might sеem ехtraordinary until wе rеmеmЬеr th:rtWilliams (|966) aссеptеdmr.rltilеvеl sеlесti
Riсhегson,P. J.' and R. Bс Тrапsformed Нumап SoЬеr,Е., and D. S. Wilso UпselfishBеhаuior.С .!Иilliams, G. С. 1966.Ad| Сurrепt Еuolutioпаrу 1992.Nаturаl Sеl UnivеrsityPrеss. Williams,G. C., and R. М QuаrtеrlуRеuieш'o Wilson, Е. o., аrrdB. Hol Proсeеdiпgsof thе N.

Group Sеlесtioп )ns. Dеspitе multilеvеl sеlесtion thеrаmеwork for studying maior transirtion is not statiс Ьut сan itsеlf еvolvе. on within groups is supprеssеd, еnnе thе primary еvolutionary forсе. J not appеar until thе 1970s and was ady it sееmslikеly to еxplain thе еvolnd HolldoЬlеr 2005) and humans as 'Ьm 1999\. Thе traits assoсiatеd with 'prеsssеlесtionwithin groups' similar lmеsand thе rulеs of mеiosis, еnaЬling primary еvolutionагy forсе. Сultural еry diffеrеnгin thеir phеnotypiс propnilar. Multilеvеl sеlесtion has Ьесomе f human сultural еvolution, in еxaсtly sitions(Riсhеrsonand Boyd 2004). sееmехtraordinary until wе rеmеmilеvеlsеlесtionas a thеorеtiсal framеЬasis of an еmpiriсal сlaim that it is tp sеlесtion. \Whеn \й/illiams сhangеd rpiriсal еvidеnсе, hе himsеlf rеvеrtеd ,lе-Ьiasеdsеx ratios (.Williams 1992, . to rеalizе that sеlесtion in fеmalеnalеs,and that it is only thе sеlесtion [еmalеЬias.''For thе еvolution of vir. ..Thе and Nеssе 1991' 8), hе statеd, rеlativе strеngths of within-host and еvolution.'' las not yеt aсhiеvеd a nеW сonsеnsus. rltilеvеl pеrspесtivеappеar alongsidе to trеаt group sеlесtion as a rеjесtеd arly slow to rеflесt thе many dеvеlop960s.Thе turЬulеnt history of this imlo (2005) in an artiсlе appropriatеly r of Group Sеlесtion.''

апd thе Еuolutioп of Zgаlitаriапism arvardUnivеrsityPrеss. Епdeаuor of groupsеlесtion. iurrесtion d Selесtioпiп Rеlаtioпto Sех.Nеw York: ]ells.Nеw Hаvеn,СT: Yalе Univеrsity 5, Thе Маjor Trапsitioпso/ Lile. Nеw

Riсhеrson,P. J.' and R. Boyd. 2ОО4.Not bу GепеsАlсlпе:Нolt, СцIturе TrапsformеdHumап Еuolutioп.Chiсago:Univеrsityof Сhiсago Prеss. .!Иilson. 1998. I.JпtoOthеrs:Thе Еuolutioп апd Psусhologуof Sobеr,Е., and D. S. UпsеlfishBеhаuior.СamЬridgе,МA: Harvard UnivеrsityPrеss. Williams,G. С. 1966.Аdаptаtioпапd Nаtиrаl Seleсtioп:А Сritique of Somе СиrrепtЕuolutioпаrуThought.Prinсеton,NJ: PrinсеtonUnivеrsityPrеss. Domаiпs, Leuelsаnd Сhаllепgеs.oxford: Oxford 1992.Nаturаl Sеlесtiсlп: UnivеrsityPrеss. \filliаms. G. С.. and R. N4.Nеssе. 1991,.Thеdаwn оf Darwinian mеdiсinе' QuаrterlуRеuiеtuof Biologу66:1_22. Wilson,Е. o., аnd B. НбlldoЬlеr.2005.Еusoсiality:Origin and сonsеquеnсеs. Proсееdiпgsof the Nаtioпаl Асаdemу of Sсiепcеs\О2: 1ЗЗ67_1З371. -D.S.\{1

62

Haесkеl,Еrnst (18з4_|9t9) Еrnst Hеinriсh Philipp August Haесkеl was Сharlеs Darwin's forеmost сham. .lforld .!Var pion at thе turn of thе twеntiеth сеntury. Morе pеoplе prior to I lеarnеd of еvolutionary thеory through his voluminous puЬliсations than through any othеr sourсе. F{ts Nаtiirliсhе Scho1lfипgsgesсbichtе(Natural history of сrеation' 1868) wеnt thrоugh 12 inсrеasinglyaugmеntеdGеrman еditions (1868-1920) and wаs translatеd into thе major Еuropеan languagеs. Еrik Nordеnskiбld, in thе first dесаdеs of thе twеntiеth сеntury' iudgеd it ..thе сhiеf sourсе of thе world's knowlеdgе of Darwinisпr" (\9з6,515). Thе сrum. Ьling dеtritus of this synthеtiс work сan still Ье found sсattеrеd alоng thе shеlvеsof most usеd-Ьook storеs.Diе Wеltr|ithsel(Thе world puzzlеs, 1899), whiсh plaсеd еvolutionary idеas in a Ьroadеr philosophiсal and soсial сontехt, sold ovеr 40,000 сopiеs in thе first yеar of its puЬliсation and wеll ovеr 15 timеs that numbеr during thе nехt quartеr сеntury-and this only in thе Gеrman еditions. (By сontrast, during thе thrее dесadеs Ьеtwееn 1859 and 1890, Darwin's Оп the Оrigiп of Speсiessold only somе 39,000 сopiеs in six Еnglish еditions.) Bу |972, Die Weltrtithsel had Ьееn trаnslatеd' aссording to Haесkеl's own mеtiсulous taЬulations' intсr 24 languagеs, inсluding Armеnian, Сhinеsе, HеЬrеw, Sanskrit, and Еspеranto. Thе young Mohandas Gandhi had rеquеstеd pегmission to rеndеr it intо Gujarati; hе Ьеliеvеd it thе sсiеntifiс antidotе to thе dеadly rеligious wars plaguing Indiа. Haесkеl aсhiеvеd many othеr popular sllссеssеs'and hе produсеd morе than 2О |argetесhniсalmonographs on various aspесts of systеmatiс Ьiology and еvolutionary history. His studiеs of radiolarians, mеdusaе' spongеs' and siphonophorеs rеmain stаndard refеrеnсеs today. Thеsе works not only informеd thе puЬliс' Ьut thеy drеw to Haесkеl's small univеrsity in Jеna thе largеst sherе of Еuropе's grеat biologists of thе nехt gеnеrаtion, among whom wеrе Riсhаrd Hеrtwig (1850_19З7) and his Ьrothеr Osсar Hеrtwig (7849_1922)' Anton Dohrn (1840_1909)' Hеrmаnn Fol (1845_1892), Еduard StrasЬurgеr(1844_1912), !и. o. Kоvalеvsky (1842_1883), Nikolai Mikluсho-Мac|aу fl846-1888)' Arnold Lang (1855_1'914),Riсhard Sеmon (18.59_1918)'lfilhеlm Roux (185О-1924)' and Hans Driеsсh (|867_7947). Haесkеl's influеnсе ехtеndеd far into suссееding gеnеrations of Ьiologists' many of whom rесallеd rеading his popular works as young studеnts. Haесkеl rесеivеd his mеdiсal dеgrее fгom !ИijrzЬurg in 1858, aftеr whiсh hе plannеd to do his haЬilitation with Johannеs Мiillеr (1801_1858)at 622

Bеrlin. Мiillеr's suiсiс Jеna, who Ьесamеhis Siсily, hе fеll in with . Flеrmann Allmеrs (1 giftеd paintеr (sее fig sеаrсh for thе lifе . ( 1 8 3 5 - 1 8 6 4 ) ,h i s f i r s t сarееr. With a small tl his rеsеarсh on thе lit of a pinhеad that sесr ing his haЬilitаtion Ьz riсh Bronn's (1800-1

сonvеrt. Нis rеsеarсh сеnt two-volumе foliс own illustrations. Thе volumеs Ьy way of inl rhе аddеd Ьепеfiсof а traordinarius profеsso Нaесkеl's Ьrilliant l tееn months suddеnlу гесovеry hе wrotе his сrееd. Rathеr, hе wou Darwinian promisе o сonviсtion in сonsidе tion of Darwinian idе l{ts Gеnerellе Мor1lhс isms, 1866) laid dowr for thе rеst of his саrе Darwin but morе сar( Ьook Fiir Dаrшiп (18(

sition that thе еmЬryo phologiсal stagеs as t Gеnеrellе Мorpbolсlgi with nеologisms that 1 есology' and a host of duсеd trее diagrams t morphologiсal and tеr by advanсing a Goеth for thе naturalist: Go, еxprеssions of thе sam lеy (1825_1895)init Мorphologie' shorn o In ordеr to sееk a w еrеd a sеriеs of popul phology. Thе sеriеsw Sch6pfuпgsgeschiсbtе

Hаесkеl

]harlеs Darwin's forеmost сham. [oге pеoplе prior to lй/orld !7аr I s voluminous puЬliсations than h ijpfuпgsgesсh i сhte (N atural his:еasinglyaugmеntеdGеrman еdithе maior Еuropеan languagеs. l twеntiеthсеntury' judgеd it ..thе г w i n i s m ' (' 1 9 з 6 . . 5 1 5 )T. h е с r u m . :ill Ье found sсattеrеd along thе iithsel(TЬе world puzzlеs, 1899), [еr philosophiсal and soсiаl сonr of its pLrЬliсationand wеll ovеr tеr сеntury-arrd this only in thе гhrееdесаdеsЬеtwееn 1859 and l d o n I ys о m е З 9 . 0 0 0 с o p i е s i n s i x had Ьееntranslаtеd,aссording to 24 languagеs,inсluding Armеnto. Thе yor'lngN1ohandasGandhi ujarati;lrе Ьеliеvеd it thе sсiеntifiс ng Indiа.Нaесkеl aсhiеvеd many orе than 20 largе tесhniсal mono. ogv and еvolutionarylristoгy. His a n d s i p h o n o p l t o r е sг е m a i n s t a n . 'ly informеd thе puЬliс' Ьut thеy hе largеstsharе of Еuropе's grеat ; rvhom wеrе Riсhard Hеrtwig шig (1849_1922), Аoton Dohrn ldr'rardStrаsЬurgеr (1 844-79 12|, Мikluсlro-Maсlay (1 846_1 888), l n ( 1 8 5 9 _ 1 9 1 8 ) ,$ 7 i l h е l m R o u х l1). Haесkеl's influеnсе eхtеndеd ' n]anyof whorrrrесallеd rеading t \WiirzЬurgin 1858, aftеr whiсh l h а n n е sM t i l l е r ( 1 8 0 1 _ 1 8 5 8 ) a t

Bеrlin' Miillеr's sLtiсidеlеd hiпl to turn to Саrl GеgеnЬaur (7826-190З) at Jеna,who Ьесаmehis advisеr. During his rеsеarсhwork in southеrn Italy and Siсily,hе fеll in with a group of Gегman artists' among whom was thе poеt Hеrmann Allmеrs (182I_1902), who Ьесamе a lifеlong friеnd. Haесkеl, a giftеd painгеr (sее figuге on pagе 624), rhought of giving up Ьiologiсal rеsеarсh for thе lifе of a Bohеmian; only his Ьеtrothal to Anna Sеthе (1835-1B64), his first сousin, kеpt him foсr'rsеdon еstaЬlishinga profеssional сarееr..Witha small traсt Ьy Millеr as his inspiration, Haесkеl сonсеntratеd his rеsеarсhon thе littlе-known groLrpof rаdiolaria, сrеaturеsаЬout thе sizе of a pinhеad that sесrеtееxoskеlеtonsof unusual gеoпrеtriеs.\7hilе сomplеting his hаЬilitаtiorr Ьасk in Bегlin, lrе rеad Darwin's Оrigin in Gеorg Hеinriсh Bronn's (1800_1862) Gеrman translation and immеdiatеly Ьесamе a сonvеrt. His rеsеагсhfinally yiеldеd, in 1862, Die Rаdiolаrieп-a magnifiсеnt two-volumе folio having ехtraordinarily Ьеautiful platеs Ьasеd on his own illustrations.Thе Ьook won thе admiration of Darwin, who rесеivеdthе volumеs Ьy way сlf introduсtion to this nеw disсiplе. Haесkеl's rеsеarсh hаd thе addеd Ьеnеfitof allowing him to marry Anna and to Ьеgin his lifе as ехtraordinariusprofеssor in thе mеdiсai sсhоol at Jеna. Haесkеl's brilliаnt Ьеginning turnеd dаrk in 1864 whеn lris wifе of еightееn months suddеnly diеd. ГIе suffеrеd i1 nеrvous сollapsе, and during his rесovегyhе wrote his p:rrеntsthаt hе сould no longеr aссеpt thеir rеligious сrееd.Rathеr, hе would put his faith in somеthing morе rеliaЬlе,namеly, thе Darwinian promisе of progrеssivе trensformation. Hе thеn dеvеlopеd that сonviсtion in сonsidеraЬlеdеtail in a largе two.volumе, thеоrеtiсal appliсa. tion of Darwinian idеas to all arеаs of Ьiology, inсluding humаn еvolution. His cепerеllе Мorphologiе dеr Оrgапismеп (General morphology of organisms, 1866) laid down thе fundamеntаl сonсеptions that hе would сultivаtе for thе rеst of his сarееr' Hе r-nadесеntral an idеa that hе found intimated in Darwin Ьut morе саrеfirlly workеd out Ь,v Fritz Мijllеr (7827_1897) in his Ьook Fйr Dаrшiп (1864), namеly, thе prinсiplе of rесapitulation-thе proposition that tlrе еmbryo of a givеn spесiеs would pass through thе samе пrorpholоgiсal stagеs as thе phylum had in its еvolutionary dеsсеnt. Haесkеl's Geпerеllе Мorphologie formulatеd sеvеral nеW pеrspесtivеs, outfitting thеm with nеologisms that gavе his trеatisеa formidaЬlе сast: phylum' ontogеny' есology,and a Ьost of othеr tеrms that had a shortеr lifе span' Hе alsо introduсеd trее diagrams to illustratе thе dеsсеnt of spесiеs and to suggеst thеir morphologiсal and tеmporal distanсеfrom onе anothеr. Thе book сonсludеd Ьy advanсing a Goеthеan monism аs thе appropriatе mеtaphysiсаl position for thе naturalist: God irnd nаturе' mind and Ьody '*,еrеto Ье rеgaгdеd as ехprеssionsof thе samе undеrlying Urstиif . Darwin and Thomas Hеnry Hux. lеy (1825_1895) initiallv sought to havе аn aЬridgеd vегsion of t|le Geпеrеlle Мorphologie, shorn of its polеmiсal ЬarЬs, trаnslatеdinto Еnglish. In ordеr to sееk ir widеr audiеnсеfor his thеorеtiсаltrеatisе'Haесkеl dеlivеrеd а sеriеs of popular lесturеs in 1868 summarizing his Darwinian nrorphоlogy. Thе sеriеs was puЬlishеd thе samе yеar цndеr thе tjt\eNаtйrliсhе Sсh\pfuпgsgеsсhiсhtе,аnd it aсhiеvеd immеdiаtе notoriеty. In an initial

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Hаechеl

.1

о

rеviеw, Ludwig Rtiti Наесkеl witl.r fгaud rесapitulatiOn-or t} rеprеsеntеdvеry your iсally idеntiсal. Rtitir сasе Ьy using thе san (1870),Haесkеl r-rs еarly stagе аnс1sаid i tlе Ьесarrsе,v()uсаnn and thе сhi.rrgесrffra Dеspitе thе сontro ful impасt on its rе. rеprеsеntеd ninе spе vеlopmеnt' with thе tо roots io t|lе Urпt t h е h i g h е s tl е v е l ,с a r Jеws, and AraЬs. Al mon to ninеtееnthan attitudе whiсh or guеd, following his f gradеs of humzrn m. and that tlrе Еuropе ingly сomplех mind-

е

of Мап.

In 1867, aftеr vis Нaесkеl travеlеd to pеrformеd thе kinds that would gаrnег f: latеr. Hе also Ьеgan'

fl4#':ч Еrnst Haесkеl was a Ьrilliаnt агtistand always fillеd his Ьсlсlkswith his owгl drawings.TЬis onе, rеvеalingl,v laЬеlеdthе ..Apothеosisof Еvоlutiсlna11, Thought'' (from thе supplеmеntto Haeсkеl's\Yапdеrbildеr,190.l)'is an intеrеstingrеflесtionon his owtr privatе lifе-hе was griеving thе dеath оf ir young wоInan' tO Whom hе wаs r"rotmarriеd Ьut with rvhom hе had just hаd a Passionatе(spiritualЬut also phvsiсal)аffаir-as wеll .rsthе сЬangingtimеs. Sigmund Еrеud'sThree Еssауsrlп tlle Thеorу сlf Sехuаlitl,(grеatlyinfluеnсеdЬy Нaесkеl'sthinkirrgоn rесаpitul;rtiоn) wаs puЬlishеdin thе sаmеyеаг this piсturе appеaгеd.

would yiеld a thrе spongеs' |872). |n l maintainеd Was nесс еmpiriсal proof thаt Haесkеl also аrgtrеd organism, having tlr mеtаzoans in gastru

thеory. Bесausе of his var сеivеd thе сommiss сlassеsof orgаrrisms hе сomposеd sеr'е siphonophorеs, and othеr author in thе thе high rеgard of tl That rеgаrd was alsс rесеivеd during his l:

Lач

Hаесkel rеviеw, Ludwig Rittimеyеr (1825_1895), an еmЬryologist at Basеl, сhargеd Haесkеl with fraud. Hе oЬsеrvеd that in illustrаting thе prinсiplе of rесapitulation-or thе Ьiogеnеtiс lаw' as it Ьесamе known-Нaесkel had rеprеsеntеdvеry young еmЬrvos of a dog, сhiсkеn' and turtlе as morphologiсally idеntiсal. Riitimеyеr maintainеd' howеvеr, thаt Haесkеl had madе thе сasеЬy using thе samе woodсut thrее timеs. In thе nехt еdition of thе Ьook (1870),Haесkеl usеd only onе illustration of a vеrtеЬratееmЬryo at a vеry еarly stagе and said it might as wеll bе thе еmЬryo of a dog, сhiсkеn, or turtlе Ьесausе you сannot tеll thе diffеrеnсе. Thе damagе, howеvеr, was donе, and thе сhargе of fraud would haunt Haесkеl for thе rеst of his days. Dеspitе thе сontrovеrsу, |trаtiirliсhe Sсhopfuпgsgesсhicbte madе a powеf{ul impaсt on its rеаdеrs, еspесially on thе topiс of human еvolution. Hе rеprеsеntеdninе spесiеs of humаn Ьеings along a trее of еvolutionary dеvеlopmеnt,with thе Papuans and Нottеntots at thе lowеst Ьrаnсhеs, сlosеr to roots iл tЬe Urmепsсh, or apе-man' and with thе Сauсasian branсh at thе highеst lеvеl, сarrying at thе top rеaсhеs thе Меditеrranеans' Gеrmans, Jеws, and AraЬs. Although Haесkel sharеd many of thе raсial viеws сommon to ninеtееnth-сеntuгyЕuropеans, hе was dесidеdly not anti-Sеmitiс' an attitudе whiсh onе of his disаffесtеd studеnts hеld against him. Hе arguеd' fоllowing his friеnd, thе linguist August Sсhlеiсhеr (1821_1868), that gradеs of human mеntal aЬility ехprеssеd gradеs of languagе сomplеxity and that thе Еuropеan and Sеmitiс languages hеlpеd сrеatе a сorrеspondingly сomplех mind-a gеnеral thеsis that Darwin adoptеd in The Desсеnt

of Мап.

llеd his Ьooks with his owrr rthеosisof Еvolutiona11mdеrbildеr' 1905), is an wаs griеving thе dеath of a with whсlm hе had just had а l wеll as thе сhаnging timеs. Sехuаlitу (grеаtly influеnсеd Ьy hеd in thе sаmе yеаr this

|л 1867, aftеr visiting Darwin and othеr British sсiеntists in Еngland, Нaесkеl travеlеd to thе Саnary Islаnds with thrее rеsеarсh assoсiatеs.Hе pеrformеd thе kinds of ехpеrimеnts on dеvеloping siphonophorе еmЬryos that would garnеr famе for Wilhеlm Rouх and Hans Driеsсh somе 20 yеars latеr. Hе also Ьеgan work on a systеmatiс analysis of сalсаrеous spongеs that would yiеld a thrее-voiumе study, Die КаlksсЬш,ijmmе (Thе сalсarеous spongеs' 1872). In this work, Haесkеl attеmptеd to providе what Bronn maintainеd was nесеssaryto show thе viaЬility of Darwin's thеory, namеly, еmpiriсal proof that spесiеsdеsсеntWas morе than a thеorеtiсal possiЬility. Haесkеl also arguеd, еmploying thе Ьiоgеnеtiс law, that in anсiеnt timеs an organism, having thе struсturе of a primitivе spongе (and thе form takеn Ьy mеtazoansin gastrulation),pliеd thе anсiеnt sеas. This Ьесamе his gastraеa thеory. Bесausеof his various invеstigationsof marinе invеrtеЬratеs,Haесkеl rесеivеd thе сommission in thе latе ]870s to dеsсriЬе systеmatiсally sеvеral сlassеsof organisms drеdgеd up Ьy HМS Сhаlleпgеr. ovеr a 10-yеar pеriod, hе сomposеd sеvеral largе volumеs on mеdusaе, сalсarеous spongеs' siphonophorеs, and radiolaria-with morе pagеs produсеd than Ьy any othеr author in thе sеriеs of Сbаllепgеr rеports. Thе сommission indiсatеd thе high rеgard of thе sсiеntifiс сommunity fоr his work in marinе Ьiology. That rеgaгdwas аlso ехprеssеdЬy thе many honorary dеgrееsand аwards hе r е с е i v е dd u r i n я .h i s I r Г е t i m е .

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Ifаеckel Rеsеntmеnt Ьy thе biologiсally and rеligiоusly ortЬodox сontinuеd to build against Haесkеl throughout thе 1870s, and it has not aЬatеd in to this day. In I874, the Swiss еmЬryologist \Wilhеlnr His (1831_1904) ptrЬlished Uпseте Kбrperform uпd dаs phуsiologiscbe Problem ihrеr Еntstеhиng (Оur Ьodily form and thе physiologiсal proЬlеm of its origin), whiсh rеpеatеdthе еarliеr сhargеs of fraud against Haесkеl and institutеd nеw onеs. Among othеr сlaims, Нis assеrtеd that Haесkеl had rеprеsеntеd thе humаn еmЬryo with zrn ехaggеratеdlу long tail-а сontrovеrsy tlrirt Ьесamе knоwn as tЬe Schш'апzfrаgе' |n 1877, Rudolf Viгсhow (7821_1902) rеjесtеd l-risonеtimе studеnt's еfforts to havе еvolutionary thеory taught in thе lowег sсhools in Gеrmаny. Virсhow сhargеd that еvolutionary thought aЬеttеd soсialists and сommunists' a сlaim thаt Нuхlеy thought quitе sсurrilous Ьесausе of its inflammatory сhilraсtеr in Bismаrсk's Gеrmany-although, in faсt, many Marxists (е.g.,August BеЬеl, 1840_1913) did find Darwinism сongеnial. At thе tuгn of thе сеnrury, rеligious opponеnts of Haесkеl,s Weltriithsеl and of his nеwly еstaЬlishеd Monist Lеaguе rеnеwеd thе сlaims of falsеhood. Thеsе many сhargеs had thеir foundation in Наесkеl,s aсknowlеdgеd slip in 1868, Ьut thеrеaftеrthеy gainеd forсе mostly from intеllесtuаl rесalсitranсеаnd rеligious dogmarism. Morе rесеntly,Daniеl Gasman (197 |) and StеphеnJay Gould (1977) arguеd that Haесkеl's Ьiology supportеd Nazi raсism, although thеy сonvеniеntlyignorеd Нaесkеl's philo.Semitism, an attitudе quitе unusual for thе pеriod. Мiсhaеl Riсhardson rееxaminеd Haесkеl's illustrations of emЬryos, and hе too suggеstеdHaесkеl's malfеasanсе.Riсhardsоn сompаrеd Нaесkеl's illustrations with photographs of еmЬryos, and еasily showеd thе dеviаrtions'Howеvеr, Haесkеl had adaptеd illustrations from thеn-сontеmporarysourсеs.Hе showеd that whеn you linеd up dеpiсtions геndеrеdЬy еxpеrts' thе similarity of еvolutionarily rеlatеd typеs at еirrliеr stagеs of еmЬryogеnеsis Ьесamе manifеst-a phеnomеrron aсknоwlеdgеd Ьy todаy's еmЬryologists. Сrеationists and Intеlligеnt Dеsign thеorists havе сitеd thе oldеr Gегmаn litеraturе and Riсhardson's photogrаphs to indiсt not only Haесkеl Ьut all of еvolutionary thеory. вlвLIoGRAPнY Dаrwin' с. l860. Ubеr die Еntstchuпgder Аrtсn im Тhiеr-иnd Pflапzеп-Raiсb durсh паtЙrliсhеZйсbtuпg odеr,Еrhаltuпgdеr uеrt,сlllhommneteп Rаssеnim Kаmpfе иm's Dаsеуп.H. Bronn, trllns.Stuttgart:SсlrwеizеrЬаrt,sсlrе Vеrlagshаndlung. Di Gregorio,М.2005. From Hеre to Еtеrпitу:Еrпst Наесkеl апd SсiепtificFаith. Gottingеn:Vandеnhoесkand Ruprесlrt. Driеsсlr,Н. 1891. Еntwiсklungsmесhаnisсlrе Studiеn.Zеitsсhriftfilr шissеnsсhаftliсЬc Zoologiе 53: 160_184. Gasman,D. 197|, Thе SсieпtifiсОrigiпs of Nаtioпаl Soсiаlism'Nеw York: Sсiеnсе H i s г o г yP u b l i с а t i o n s . Gould, S. J. 1977.Опt
l868.Dlс Na/йr | 8 7 2 .D i с К а l k s t899, Diе \Yeltr H i s , W . | 8 - 4 . U l t s с r сК i i Еntstеhuпg.Lеipzig: Krаussе,Е. 1984.ЕrпstI Miillеr, F. 1,864.Рiir Dаr N o r d е n s k i o l dЕ, . I l 9 2 0 _ PuЬlishing. Pеnnisi,Е. 1997. Наесkе Riсhards,R. J. 2005.Tht Haесkеl'sеr,olution Мапу Fасesоf Еuolt 2ОО8.Тhс Тrаg' Еuolutioпаrу Тhllug R o u х ,W . l l t 8 8 'B е i t r i g pаthсll,'gisсllсAпаtl' 113-153,246-29

Haldanе,J.B. s. (

John Burdon Sandеrs N o v е m Ь е г5 ' l 8 9 2 ' i n t h е p h y s i с i а nJ o h n S с d a n е ( l a r е rМ i t с h i s о n t o с г a t s J. . B ' S . H a l d а r thе modеrn synthеtiсtl а n d S е w а l lW r i g h t ( l l

t о Ь i o с h е m i s t r y .I n e d Wr1tеr. H a l d a n е W а sе d u с a lеgе, oxford, in Еngla е m а t i с s s с h o l a r s h i pr

honors ii-rmathеmatiс H siсs and phil
с l i l i g е n t I yo n l i I r k a g е Ьridgе Univеrsitу, wh Ь е с а m е ,w i t h F i s h е r.

Hаldапe rsly orthodoх сontinuеd to Ьuild : has not aЬatеdin to this day. In (1831_1904)puЬlishеd Uпsеrе n ihrer Епtstеhuпg (our Ьodily .igin),whiсh rеpеatеdthе еarliеr d nеw onеs.Among othеr сlaims, lе human еmЬryo with an еxagmе known as tЬe Schtuапzfrаgе. :tеdhis onеtimе studеnt's еfforts .еrsсhools in Gеrmany. Virсhow ,сialistsand сommunists' a сlaim o f i t s i n f l a m m a t o r yс h a r a с t е ri n ny Мarхists (е.g.,August BеЬеl, At thе turn of thе сеntury, rеliand of his nеwly еstaЬlishеd hood. Thеsе many сhargеs had slip in 1868, Ьut thеrеаftеrthеy r r а n с еа n d г е l i g i o u sd o g m a t i s m . tеphеnJay Gould (1977) arguеd r, althoughthеy сonvеniеntly igе quitе unusual for thе pеriod. illustrations of еmЬryos, and hе rdson сomparеd Haесkеl's illussily showеd thе dеviations. Howthеn-сontеmporary sourсеs. L{е ndеrеdЬy ехpеrts,thе similarity гagеs of еmЬryogеnеsis bесamе today's еmЬryologists. Сrеatiоntеd thе oldеr Gеrman litеraturе : only Haесkеl Ьut all of еvolu-

im Thiеr- uпd Pflаnzеп-Rеiсh lеr uеruс,llkommпеtсrtRrlssеп im ;art: SсhwеizеrЬart'sсhе .nst Наеckеl апd Sсieпtifiс Fаith. lien, Zеitsсbrift fiir паl Soсiаlism. Nеw York: Sсiеnсе n b г i d g еМ , A: Harvаrd Univеrsity аdiаriа):Еiпе Мoпсlgrаpbie. 2 vols. smеn'2 vols. Bеrlin: Gеorg Rеimеr.

Bеrlin:Gеorg Rеimеr. 1868.Diе NаtйrliсhеSсhсlpfипgsgesсhicbtе. 1'872.Diе Kаlkschшiimme.3 vols. Bеrlin:Gеorg Rеimеr. Bonn: Еmil Strauss. 1899' Diе Wеltrijthsеl. .W. His, 1874.lJпsеrеKorpеrfсlrmипd dаs phуskiogischеProblеm ihrer Епtstеhuпg. Lеipzig:Vogе1. Kraussе,Е. 1984,Еrпst Hаесkеl.Lеiрzig:ТеuЬnеr. Mtillеr,F. 1864.Fйr Dаrшiп.Lеipzig:Еngеlmann. Nordеnskiold,Е. |1920-7924|1936.Thе Historу of Bbbgу' Nеw York: Tudor PuЬ1ishing. Sciепсе277:1'435. Pеnnisi,Е, 1997.Hаесkеl,sеmЬryos:Fraud rеdisсoуеrеd. and morрhologiсalfoundationsof Еrnst Riсhards,R. J. 2005.Thе aеsthеtiс Hаесkеl'sеvolutionary рroiесt.In М. Kеmpеrinkand P. Dassеn,eds.,The Мапу Fасеsof Еuolutklniп Еurсtpе'1860-1914.Amstеrdam:Pееtеrs. 2О08.Thе Trаgiс Seпsеof Lifе: Еrпst Hаесkеl апd thе Strugglеouеr ЕuolиtioпаrуThought.Сhiсago:Univеrsityof Сhiсago Prеss. dеsЕmЬryo,Аrсhiu fйr Rouх,!7. 1888.Bеitrigеzur Еntwiсkеlungsmесhanik pаthologisсhеАпаtсlmiеund Phуsiсlltlgiеuпd fйr kliпisсhеМеdiсiп 94: -R./.R. 113*153,246-291.

Haldanе,J. B. s. (L892_|964) John Burdon Sandеrson Haldanе, known familiarly as J. B. S.' was Ьorn on NovеmЬеr 5, 1.892,in ЕdinЬurgh, Sсotland, to Louisa Kathlееn Haldanе and thе physiсian John Sсott Нaldanе. J. B. S.,s youngеr sistеr was Naomi Haldanе (latеr Мitсhison). Thе Нaldanе family is dеsсеndеdfrom Sсottish aгistoсrats.J. B. s. Haldanе is known prinсipally aS onе of thе thrее arсhitесtsof thе modеrn synthеtiс thеory of еvolutiоn, along with R. A. Fishеr (1890_1,962) and Sеwall Wright (1889_1988). Haldanе also madе original сontributions to Ьioсhеmistry.In addition, hе was a populаг sсiеnсе,politiсal, and fiсtion Wrltеr. Haldanе wаs еduсatеd at thе Dragon Sсhool, Еton Collеgе, and Nеw Сollеgе'oxford, in Еngland. Не еntеrеdNеw Сollеgе in \911' Ьy wаy of a mathеmatiсs sсholаrship Won at Еton. A yеar latеr, Haldanе won first-сlass honors in mathеmatiсs and suЬsеquеntly,in 1.914,first-сlasshonors in сlassiсs and philosophy. Наldanе did not possеssa sсiеnсеdеgrее'yеt his intеrеst in sсiеnсе dеvеlopеd at аn еarly agе, mainly duе to thе influеnсе of his fathеr and sistеr.In 1901, whеn Нaldanе Was еight, hе and his fathеr attеndеda lесturе whеrе thе Ьiologist A. D. DarЬishirе (1879_1915) disсussеdthе nеwly геdisсovеrеdpгinсiplеs of Меndеlism. Along with his sistеr,who was Ьrееding guinеa pigs, Haldanе did еxpеrimеnts looking for pattеrns of Mеndеlian hеrеdityin 1908. Bу 1912, Haldanе Ьеliеvеdhе had еvidеnсеof linkagе (i.е., thе inhеritanсе of two allеlеs togеthеr),and in 1915, Ьеforе еntеring !Иorld lVar I as a mеmЬеr of thе Sсottish Blaсk \й/atсh,his viеw was publishеd in thе Jourпаl of Gепеtics. In 7919, Haldаnе Ьесаmе a fеllow of Nеw Сollеgе, Oхford. Hе workеd diligеntly on linkagе, puЬlishing sеvеral papеrs. In t922 hе movеd to Сam. Ьгidgе Univеrsity, whеrе hе would stay until 19З2. Аt СamЬridgе, Hаldanе .s7right, a kеy figurе in thе synthеsis of Darwinian Ьесamе, with Fishеr and

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628

Наldапe natural sеlесtion with thе prinсiplеs of Меndеlian hеrеdity.Indееd,Haldanе would play no smаll rolе in uslrеring in thеorеtiсal population gеnеtiсs.In 1924,Ha|danе puЬlishеd thе first of a sеries of 10 mathеmatiсal papеrs ехploring thе reсonсiliation of Darwinism with Mеndеlism; thе last in thе sеriеs was puЬlished in 19З4, just tw
сal Institutе. In his tr Haldanе arguеd that of a suЬstitution load in еnvironmеnt) сoul( Haldanе's сlaim was Haldanе was aw21 1958, and in 1961 r, еmy of Sсiеnсеs.Aftс BhuЬanеswar, orissa did not dampеn Halt ..I know th hе wrotе, And it сan hurt onе 1 spot of laughtеr, I an do our Ьit i To hеlp tl dеsсriЬеd as largеr th wit, and his politiсal somе.

BlвLIoGRAPH

Сlark, R. !и. 1968./B5 МсСann. H a l d a n е J' . B . S . 1 9 2 З Trеnсh,аnd TruЬп l924.A mаth Тrапsасtioпsof tb |927. Possibl 1929.Thе orig 193О.Епzуtlt |932. Тhе Саt 1934.A mаtlr 19 472429. 1937.Thе еffе 1957.Thе сos Haldanе,J. B. s.' A. D. Jourпаl of Gепctiс

Hamilton, W.D,

William Donald Ha: thе twеntiеth сеntur Darwin, partly Ьесa Partly Ьесausе Ьoth Pеrhaps thе laгgеstс aсts that Ьеnеfit othе ory suggеststhat mu wipе out altruism, whilе thе sеlfishindi naturе. Afriсan kin1

Hаmiltoп еlian hеrеdity.Indееd, Haldanе orеtiсalpopulation gеnеtiсs. In of 10 mathеnratiсalpapеrs ехMеndеlism; thе last in thе sеriеs r puЬliсation of his Ьook ТЙe aldаnе'ssеriеsof papеrs on еvo_ o f t h е o r е t i с apI o p u l а t i o n g е n е his сontеmporariеs;hе wаntеd natural sеlесtionin N{еndеlian ry pгimartly foг its сritiсal сomown mathеmatiсalеxplorations n that. Haldanе aссomplishеs a dеlian hеrеdity,Ьut also, undеr sonrаlmесhaniсs,сytology, and е's work was by no mеans rеlishеd his famous Dаedаlиs, or : on sсiеnсеin its soсial сontеxt. 's friеnd Aldous tluх|eу,s Brаuе ibutеd Haldanе's prinсiplе, thе y еquipmеnt animals rеquirе, in a thе сollесtion Possiblе Worlds ationson thе origins of lifе wеrе r Oparin (1894-1980). In 1930, эns of еnzymе kinеtiсs. Dеspitе l Сharlottе Frankеn Burghеs in lе Сharlottе was marriеd at thе эforеmarrуing Haldanе. J. B. s. st Неlеn Spurwаy in 1945. Сol1еgе,London, and Ьесamе ,.Thе ldanе publishеdhis papеr, thе dесlinеof thе avеragеfitnеss LalallеlеWas proportional to thе : in fitnеss.Haldanе's сonсlusion utation load.'' At this timе, HalLгtyand, in faсt' wrotе a numЬеr illу Workеr. In 1950, Нaldanе lism and to thе сrimеs of Soviеt : Soviеt Union during whiсh sсi)arwin Wеrеsеnt to thе gulags. l of thе Royal Soсiеty in 1953, thе Univеrsity of Paris in 1956. rtеd to India аnd ultimatеly Ье)tеstof British poliсy during thе t DгofеSsorаt thе Indian Statisti-

сal Institutе.In his famous papег, ..Thе Сost of Natural Sеlесtion'' (1957), Haldanе arguеd that thеrе is a сap on thе ratе of adaptivе еvolutiorrЬесi.tusе of а suЬstitutionl
Hamilton,W. D. (1936-2000I !7illiam Donald Hamilton was onе of thе major еvolutiorraryЬiologists of thе twеntiеth сеntuгy. Мany of his сontеmpor:rгiеsсomparеd lrim to Сharlеs Darwin' partly ЬесausеЬoth rrrеnsharеd а dееp lovе of natural history and partly Ьесausе both attemptеd to solvе somе of Ьiology's Ьiggеst mystеriеs. Pеrhaps thе largеst of thеsе mystеriеsis thе quеstion of altruism, pеrforn-ring aсts that Ьеnеfitothегs at a сost to thе altruist. Strpеrfiсiаlly,еvolutionary thеory suggeststh21tmutants ехhilliting morе ..sеlfish''Ьеhzrviorshould Ье zrЬlеto wipе out altruisrn, Ьесausе Ьy dеfinition thе altruists hаvе rеduсеd fitnеss whilе thе sеlfishindividuals prospеr at thеir еХpеnsе.Yеt altruism aЬounds in natuге. Afriсan kingfishеrs fееd and protесt young that arе not thеir own;

6З0

Hапtiltoп lronеyЬeеsсommit suiсidе whеn thеy sting intrudеrs, and еvеn morе notaЬly from an еvolutionary pеrspесtivе' workеr Ьееs arе stеrilе, saсrifiсing thеir own rеproduсtion to hеlp thе hivе flоurish. Harnilton's ir-rsightfor solvir.rgtlrе puzzlе rvirs dесеptivеl1,simplе: sеlfsaсrifiсial ЬеЬаvior сan еvolvе and pеrsist if it Ьеnеfitsrеlativеsof thе altruist Ьесausеthеy sharе thе altruist'sgеnеs.Thus aiding a siЬling, сousin, or othеr rеlation сan still Ье favorеd Ьy sеlесtior-r' еvеn if it nrеans forgoirrg thе produсtion of thе altruist's own offspring. Hanriltоn еxprеssеdthis in aп еquation that lras сomе to Ье сallеd Hашrilton's rulе: аltruism is favorеd whеn Ьlc>1'lr, whеrе Ь is thе Ьеnеfit,с is thе сost of thе aсt, and r is thе dеgrееof rеlatеdnеssЬеtwееn thе dоnor and thе rесipiеnt of tlrе altruisпr. onе should thеrеforе bе пrorе likеly to sее thе most s.lсrifiсеfor thosе most сlosеly rеlatеd, suсlr as siЬlings, аnd lеss saсrifiсеfсlr thosе lеss сlosеly rеlatеd, suсh as third сousins. Thе proсеss is сallеd kirr sеlесtion,arrd thе idеa has Ьееn usеd lvith grеat suссеssto ехplain a variеty of proсеssеsin animals, inсluding thе сoopеrativе Ьirds аnd suiсidаl Ьееsmеntionеd еаrliеr, although it doеs not always providе a сomplеtе answеr. TЬе Ьееs,it turns out' arе thгough a gеnеtiс pесuliarity of thеir insесt group vеry сlt>sеlyrеlatеd to thеir hivе mаtеs, morе so than thеy rvould Ье to thеir own offspring, and hс.nсеhеlping thеir mothеr (thе quееn) to rаisе thеir sistеrsand Ьrotlrеrs,who rvill Ьесomе fr.rtr-trе rеproduсtivеs,will Ье favorеd undеr manv сirсumstаnсеs. In addition to his work on altruisпr, Нamilton wrotе aЬout thе еvolution ..Gеomеtry for of animal groups in thе Sеlfish Hеrd'' (|971), aЬout sеx ratios, aЬout aging and sеnеsсеnсе'and :rЬout thе origins and funсtion of сoopеration and fightir-rg.Мuсh of lris work is mllrkеd Ьy a r,villingnеssto еntеrtain nеw idеas and viеw old inforrтаtion witlr a frеsh еyе' and hе was a rathеr solitary sсiеntistthroughout most of his lifе. Thе idеa of kin sеlесtion wеnt rеlativеly unapprесiаtеd for sеvеrirlyеars аftеr its initial pr"rЬliсаtionin 7964,Ьut еvеntuаlly it Ьесапrеonе оf thе сornегstonеsof mоdеrn еvolutionary Ьiоlogy' His idеаs almost always Ьесamе kеy сomponеnts of thеir fiеld, whеthеr immеdiatеly or aftеr a lag whilе othеr sсiеntistsсaught up to him. Hamilton еvеntually Ьес.rmеintriguес1with onе oI thе grеatеstproЬlеms of This lеd to an intеrеstin pагеvollttion' thе еxistеnсеof sехual rеprсlсlr.tсrion. ilsitеs and thеir еffесts or-rhost есolog,v,Ьеhavior, аnd еvolutiсln that lastеd for thе rеst of his сarееr. Sех is a сonundrum Ьесausе,just as thе altruist slrould losе in a raсе with a sеlfish сonlpеtitor' an :rsехualspесiеs (onе that simply rеpгodr'rсеsitsеlf Ьу rnaking gеtlеtiсallyidеntiсаl сopiеs) shсltrldoutсompеtе a sехual spесiеs thаt rеquirеs two individuals to produсе a singlе offspring. Сеrtainly somе organisms' ir-rсludingsoпrе сrustaсеans!lizards, insесts, and plants' do rеprсlduсеasехuаlly. Мost, howеvеr' pay thе priсе of sех, with all of its сonsеquеnсеs.As Harrrilton askеd in a 1975 Ьook rеviеw, .WЬy ..Why all tlris silly rigmtrrolеof sех? Why this gavottеof сhrot-l.losomеs? :rll thеsе usеlеssmаlеs, this striving аnсl wastеful Ьloodshеd, thеsе grotеsquе horns, сolors, . . . and why' in thе еnd, novеls . . . ahout lovе?'' (p. 175). Hamilton, аlong with a tеrv othеr sсiеntists,suggеstеdthat sеlесtionmust gеnеrirtiol.ts favor thе shuff1ingof gеnotypеsЬеtrvееt-t and hеrrсеsеx. But thе

sеlесtir.еprеssurеsmust fl produсtion still wins in th i n d е г e i l L r s i n gp о p u l a t i o n vidе suсh fluсtuаting sеlес attaсk as thеir hosts еvol thе сontinual Ьarragе of i

ual rеproduсtion advanta Не tlrеn turnеd his :rttс ing tlrat thеrе, too, prеsst tion of showy sеxual orn malеsrеsistant rl plrrlsit flashy tr:ritsas indiсirtors as w,еll.Parasitеs lrrе of

u е d p r е s s u r еt r l m a i n т а i сhangе thеir dеfеnsеs,tht еasеs. Fеtnalеsthus шsе thе spесifiс gеnеs сonfеr Ьееn tеstеdin nurrlеrous ЬataЬ1е,parasitеsdсl sее vеlopnrеnt of somе sехu Nаtuгаl histor-v,part Нaпrilton, and his thеor organisms Ьеhavеdin th

of 6З, following сoпrpliс Сongo to follow up tln polio vaссinе. Hе won Kyoto Prizе, thе Сrafoс mеdiсal Ьiology), tlrе Di

mаl Bеhаvior Sсlсiеt1, Soсiеty of Natuгarlists.Е сiplirrеs,from еntomol furthеr tеstimonу to thr B|вLIoGRAPl{Y

' H a m i l t o n ,W . D . 1 9 7 1 G З1:29.5-311' 197.5.Gаmblеrss rf BюIogзl'50:l7.5-1 1 9 8 0 .S е хv е r s u 1995a.NаrroшF Nеw York: \(. H. Fr 1 9 9 5 Ь .N а r r o шI P Oхiоrd Llnivеrsitr' Rr N.lrrои 2005. Hаmiltoп.Vol.3, La

Hаmilton g intrudеrs,and еvеn morе notaЬly эr Ьееs arе stеrilе' saсrifiсing thеir h. tzzlе wils dесеptivеly simplе: sеlfif it Ьеnеfitsrеlаtivеsof thе altruist us aiding a siЬling' сousin, or othеr еvеrrif it mеаns forgoing thе pro_ l : r r n i l r oеnх p r е s s с dt h i s i n а n с q u a _ ln's rulе: altruism is favorеd whеn lst of thе aсt, anс1r is thе dеgreе of сipiеntсlf thе altrr'rism.Onе sЬould saсrifiсеfor tlrosе most сlosеly rе)r thosеlеss сlosеly rеlatеd, sttсh as lесtion,аnd thе idеа has Ьееn usеd proсеssеsin аninrals,inсluding thе lnеdеarliеr,altlroughit doеs not al;, it turns out' arе through a gеnеtiс ,ly rеlatеdto thеir hivе matеs, morе ing,аnd hеnсеhеlping thеir mothеr | е r s \' ^ ' I 1r o v i | |l l е с r l l n еf u t u r е r е p г o l l]1stаnсеs. arr.riltonwrtltе aЬout thе еvolution еlfishНеrd'' (1977), aЬout sе-хraout thе сlriginsand funсtion t;f сolrk is markеd Ьy a willingrrеss to tion with a frеslr еyе' and hе was a эf his lifе. Thе idеa of kin sеlесtion yеars aftеr its initial puЬliсаtion in сornеГst()nеs of nrodеrn еvolutionrrnе kеy сomponеnts of thеir fiеld, эthеrsсiеntistsсaught up to him. vitЬ onе of thе grеatеstproЬlеrns of - . t i t l пT' h i s I е dt t l а n i n t е r е s ti n p а г lеhavior,and еvolution tlrirt lastеd rdrum Ьесausе,just as thе altruist эtitor,an asехuаl spесiеs (one that iсаllr' idеntiсаl сopiеs) should out. vo individuаls to produсе a singlе rdingsorтесrustaсеans'lizards, in. Мost, howеvеr, pay thе priсе of ilton askеd iл a 7L)75 Ьook rеviеw, .Wlry гhisgаvottеof сhromosomеs? astеfulЬloodshеd,гhеsеgrorеsquе v е l s. . . а Ь o u t l o v е ? ' ' ( p . 1 7 5 ) . t i s t s .s u g g е s t е dt h а t s е | е с t i o nm u s г ]еnегаtionsand lrеnсе sеx. But thе

sеlесtivеprеssurеsmust fluсtuatе in еithеr spaсе or timе, or еlsе asеxual rеproduсtiоn still wins in thе long tеrm. For a variеty of rеasons Ьеst ехplainеd irrdеtail шsingр.loрulationgеnеtiс modеls, pаrasitеsarе idеaliy suitеd to providе suсh fluсtuating sеlесtionЬесausеthеy сontinually еvolvе nеw mеans of attaсk as thеir hosts еvolvе dеfеnsеsagainst thеm. Hamilton outlinеd how thесontinual Ьаrrаgе of insults Ьy pathogеnslirrgеand small сould kееp sехuaIrеproduсtion zrdvаntаgеousirr long_livеdmultiсеllular organisms. Hе thеn turnеd his attеntiоrrt
6З1

6З2

Нennig

Hеnnig, Willi (Т913-1976) In сompеtition with Сarl Linnaеus, \Willi Hеnnig is pеrhaps thе rnost influеntial systеmatist of all timе. Aftеr Сharlеs Darwin's presеntation of thе thеorу of еvolution, many biologists, inсluding Darwin himsеlf, еxprеssеd thе idеa that organisms should Ье сlassifiеd Ьasеd on thеir еvolutionary rеlationships-thеir phylogеny. Flowеvеr, it was Hеnnig who first prеsеntеd a сomplеtе thеory for phylogеny rесonstruсtion and dеvеloped thе prinсiplеs foг phylogеny-basеd сlassifiсation. As a tееnager, Неnnig Was an ardеnt amatеur zoologist. Hе сollесtеd Ьееtlеs and Ьuttеrfliеs, startеd an hеrЬarium' and workеd аs a vоluntеег in thе Drеsdеn Мusеum. Не took an intеrеst in thе sсiеnсе of systеmatiсs and, in a high sсhool еssay writtеn at thе agе of 18, hе сlеarly idеntifiеd thе rесonstruсtion of еvolutionary rеlationshipsas thе main task of the disсiplinе.Biologists at thе timе laсkеd a c|ear undеrstanding of how organismal rеlationships сould bе rеliaЬly rесonstruсtеd, Ьut Hеnnig disсussеd thе mеrits of diffеrеnt typеs of еvidеnсе of phylogеnеtiс affinity and pгеsеntеd original idеas that forеshadowеd his latеr work. Howеvеr, it would takе him аlmost twо dесadеs to dеvеlop a rigorous thеory of phylogеnеtiс infегеnсе. Hеnnig studiеd zoo|ogy, botany, and gеology at thе Univеrsity of Lеipzig, whеrе hе dеfеndеd his thеsis on thе сopulatory apparatus of Diptеra (fliеs, m o s q u i t o е s ,a n d m i d g е s )t n t 9 3 6 , a t t h е a g е o f 2 З . | n | 9 3 7 , h е j o i n е d t h е Gеrman Еntomologiсal Institutе, whеrе hе spеnt most of his еarly profеssional сarееr. Although сomparativе morphology and taхonomy of diffеrеnt groups of Diptеra rеmainеd thе maioг foсus of his work, Hеnnig Was a prolifiс writеr, puЬlishing morе than 9,000 pagеs and thousаnds of drawings during his lifetimе. In addition to thе Diptеra monographs, his writings inсludеd outstanding thеorеtiсal and еmpiriсal сontriЬutions as wеll as tеxtbooks spanning thе еntirе fiеld of zoologiсal systеmatiсs. .War Hеnnig was сonsсriptеd as an infantryman whеn NИorld II Ьrokе out in 19З9. Aftеr rесovеringfrom a sеrious injury hе suffеrеdin Russia tn |942, hе was ordеrеd to work with malaria сontrol. Shortly Ьеfoге thе еnd of thе war he was sеnt to Grеесе and northегn Italy' whеrе, in British сaptivity' hе сontinuеd with malaria work until thе fall of 1945,It was during this pеriod that hе wrotе thе draft of his most important work, Gruпdzйge еiпer Tbеorie der phуlogeпetischеп Sуstemаtik (Priпciplеs of а Theorу of Phуlogenetiс Sуstеmаtiсs' 1950). Hеnnig finishеd thе manusсript aftеr thе war, and thе Ьook appеarеd in 1950 in a small еdition and without an indех Ьесausе of thе shortagе o{ papеr at the timе. Thе tеxt wаs widеly disсussеdаmong Gегmаn-rеadingzoologists, inсluding Profеssor Lars Brundin at thе Swеdish Мusеum of Natural History in Stoсkholm' who Ьесamе a powеrful proponеnt of thе nеw idеas. Нowеvеr, Hеnnig's thеoriеs wеrе not introduсеd to the Еnglish sсiеntifiс litеraturе until a rеvisеd vеrsion of rhе book was printеd in thе Unitеd Statеs in 1966; severalrеlatеd papеrs appеarеd in Еnglish-languagеjournals around thе samеtimе.

Long Ьеforе Hеnni1 nеss of two spесiеsW; Ьеhavior, and othеr l еvoivеd simiiaritу, сt

nеalogiсal rеlationsh hеritеd from a сomm' сritеria; only thе shar' nеtiс rеlationship. Bс tor sharеd Ьy оrrly еvolutionary unit (m. r (plеsiomorphiеs)с1o сhimp, and man, tht that thеy sharе a tail tor of all four spесiе sharеd dегivеd fеatuт To Hеnnig, Ьasin1 namеd taхa must bе

thе timе by rеsеarсl-r must bе a сomPromi ity (..еvolutionary s ( 1 9 6 З ) , w h oa r g u е dt

phylogеnеtiсrеlatitln nig's prinсiplеs arе a dесadеs Ьеforе a сon

сausе of thе rеsiliеrr ..pг nospеrms,',arrd Thе rulеs for namin idеa of rесognizing f. that ranks Ье tiеd tо datе of origin. Aссul timе, Ьut thе rеfinеп molесular data mаy

Hеrrnig disсttssе sortеd from honrolt inсludеd dеtailеd ar aсtеrs in thе fоssil rс

and thе gеographiс rеsolvеd using сhес against еaсh othеr. ,

aЬsеnсеof еvidеnсе iary prinсiplе. Henl сonfliсts' suсh as p: point toward thеrn idеa to Hеnnig. Hо indеpеndеntly disс molесular Ьiologist

Heппig

g is pеrhapsthе most influеntial s prеsеntationof thе thеory of himsеlf' ехprеssеd thе idеa that volutionary геlationships-thеir prеsеntеda сomplеtе thеory for pгinсiplеs for phylogеny-Ьasеd ]ur zoologist. Hе сollесtеd Ьееd workеd as a voluntееr in thе sсiеnсеof systеmatiсs and, in a :lеarly idеntifiеd thе rесonstruс. task of thе disсiplinе.Biologists how oгgаnismal rеlationships lisсussеdthе mеrits of diffеrеnt d prеsеntеd original idеas that rld takе him almost two dесadеs irrfеrеnсе. lgy at thе Univеrsity of Lеipzig, ory apparatus of Diptеra (fliеs, : of 2З.In 79З7, he joinеd thе spеnt most of his еarly prсlfеslogy and taxonomy of diffеrеnt of his work, Hеnnig was а pro3еs and thousands of drawings . a m o n o g r а p h s ,h i s w г i t i n g s i n ,l сontriЬutions as wеll aS tехtsystеmatiсs. .!7orld.sИar :rwhеn II Ьrokе out :y hе suffеrеd in Russia in 1'942, ll' Shoгtly Ьеforе thе еnd of thе y, whеrе, in British сaptivity, hе 1945.It was during this period work, GruпdzЙge eiпer Тhеorie lf а Theorу of Phу|ogепetiс Sуswar, and thе Ьook appеarеd in dех Ьесausе of thе shortagе of ;sеdamong Gеrman-rеading zot thе Swеdish Мusеum of Natэowеrful proponеnt of thе nеw introduсеd to thе Еnglish sсiеnЬook was printеd in thе Unitеd .еd in Еnglish-larrguagе journals

Long Ьеforе Hеnnig, it was gеnеrally assumеd that thе еvolutionary rеlatеdnеss of two spесiеswas сorrеlatеd with thеir ovеrall similarity in morphology, Ьеhavioг,аnd otЬеr traits. It wаs also widеly rесognizеd tЬat indеpеndеntly evolvеd similarity, сommonly сallеd сonvеrgеnсe' was falsе еvidеnсе of gеrrеalogiсalrеlationship. But Hеnnig rеalizеd that many of thе sirrrilaritiеsinhеritеd from a сon-lmon anсеstor' сallеd homologiеs, wеrе usеlеss as grouping сritеria; only thе sharеd dеrivеd traits (synapomorphiеs) indiсatе truе phylogеnеtiс rеlationship. Bесausе a synapomorphy originatеd in a сommon anсеst o r s h a r е d Ь y o n l y s o m е o r g a l ) i s m s .i t g r o u p s t h o s е o r g a n i s m s i n t o а n еvolutionary unit (rnonophylеtiсgroup or сlade). Thе shагеd primitivе traits (plеsiomorphiеs)do not dеfinе сlаdеs. For instanсе, in a samplе of dog, Itzard, сhimp, and man, thе dog and tlrе lizаrd сannot bе groupеd on thе ground that thеy sharе a tail Ьесausе this trait was inhеritеd from thе сommon anсеstor of аll four spесiеs;it is a plеsiomorphy. Thе laсk of a tail, howеvеr, is a sharеdderivеd fеaturеthat саn Ье usеd to grouр thе сhimp and man. To Hеnnig, Ьasing Ьiologiсal сlassifiсation on phylogеny mеant that all namеd taхa must bе monophylеtiс groups. This idеа was strongly opposеd аt thе timе Ьy rеsеarсhеrslikе Еrnst gIaуr (1969), who insistеd that сlassifiсation пrust Ье a сompromisе Ьеtwееn еvolutionary rеlationship and ovеrall similarity (..еvolutionary systеmаtiсs,'),and Ьy RoЬегt Sokal and Pеtеr Snеath (196З),who arguеd that grouping Ьy ovеrall similarity was prеfеraЬlеЬесausе phylogеnеtiс rеlationships Wеrе so diffiсult to rесOnstrllсt (..phеnеtiсs'').Неnnig's prinсiplеs arе almost univеrsally aссеptеd now' еvеn though it will takе dесаdеs Ьеforе a сonsistеnt Hеnnigian сlassifiсation is univеrsally adoptеd Ье_ сausе of thе rеsiliеnсе of old group сonсеpts-suсh as ..invеrtеЬratеs,''..gyn-'nospеrms,,' аnd ..protozoansD-and tlrе laсk of knowlеdgе aЬout phylogеny. Tlrе rulеs for nanring сladеs arе still mr'rсh dеЬatеd, еspесially thе Linnaеan idеa of rесognizing formal ranks (gеnus,family, oгdеr, еtс.). Hеnnig proposеd that ranks Ье tiеd to agе; еaсh rаnk would Ье геsеrvеdfor groups of a spесifiс datе of origin. Aссuratе dating of сladеs sееmеd сomplеtеly unrеalistiс at thе timе, Ьuг thе rеfinеmеnt of phylogеnеtiс mеthods and thе growing amount of molесular data may yеt lеad to a rесonsidеration of this idеa. Hеnnig disсussеd at lеngth thе prinсiplеs Ьy whiсh сonvеrgеnсе сould Ье soгtеd from homology and plеsiomorphy from apomorphy. His tесhniquеs inсludеd dеtailеd analysis of similarity, thе sеquеnсе of appеaranсе of сharaсtеrs in thе fossil rесord or irr ontogеrry (thе dеvelоpmеnt from egg to adult), and thе gеographiс distriЬution of сharaсtегs.Сonfliсts Wегеto Ье manually rеsolvеd using сhесking and rесhесking, сarеfully wеighting thе argumеnts againstеaсh othеr' A Ьasiс idеa was that homology should Ье asstrmеdin thе aЬsеnсеof еvidеnсе to thе сontrаry' сommonly rеfеrrеd to as Hеnnig's auxiliary prinсiplе. Неrrnig nеvег disсussеd quantitаtivе tесhniquеs for rеsolving сonfliсts, suсh as parsimоny and сompatiЬility analysis, Ьut his tехts сlеarly point toward tlrеm, and somе еarly parsimony papеrs attriЬutеd thе Ьasiс idеa to Hеnnig. Нowеvеr, thе mathеmatiсsof phylogеny rесonstruсtion Was indеpеndеntly disсovеrеd at aЬout thе samе timе Ьy othеr systеmatists and molесular Ьiologists unаwarе of Hеnnig's work.

6ЗЗ

6З4

Hobbit Thе dеЬatе following thе prеsеntаtion of phylogеnеtiс systеmatiсs wаs plaguеd Ьy outragеous сontrovеrsy (Hull 1988). Somе of Неnnig's еnеmiеs laЬеlеd him ..сladist'' Ьесausе of his епphasis on rесognizing monophylеtiс groups (сladеs),and Hеnnig's morе zеalous followеrs quiсkly adoptеd thе tеrm. Aftеr Hеnnig's dеath, sеvеral prominеnt сladists arguеd that thе Ьаsis of сlassifiсation should not Ье еvolutionary rеlationship Ьut thе most paгsimonious arrangеmеnr of thе availaЬlе dаta (Ridlеy 1'986). othеrs (phylogеnеtiс systеmatists)maintainеd that parsimony was only onе of sеvеral tools that сould Ье usеd to find thе еvolutionary rеlationships on whiсh propеr сlassifiсation should геst' DеЬatеs inspirеd by Hеnnig's rеvolutionary book still сontinuе today, morе than 50 yеars aftеr its original puЬliсation. в|вLloGRAPHY Anonymous.2005' !иilli Hеnrrig.Das BiologiеWiki, http://www.Ьiologiе.dе/ Ьiowiki/!7illi-Неnnig. Dupuis, С. Т984.!Иilli Hеnnig'simpaсton tахonomiсthought.Аппuаl Reuiеtuсlf Есologу апd Sуstеmаtiсs|5: |-24. Fеlsеnstеin, J.200з. A digrеssionon historyаnd philosophу.Inlпferring Phуlogeпies,сhap. 10. Sundеrland,MA: SinаuеrAssoсiatеs. Hеnnig, !и. 1950. Gruпdziigееiпеr Thеoriеder phуIogeпеtisсhen Sуstеmаtik.Berlin DеutsсhеrZеntra|vеr\ag. 1966. PbуIogеnеtiсSуstеmаtiсs'UrЬana:Ur-rivеrsity of illinois Prеss. Hull, D. L. 1988'Sсiепсeаs а Рrсlcеss. Chiсаgo:Univеrsitуof СhiсagoPrеss. Мayr, Е. 1'969.Principlеsof SуstemаtiсZotllogу. Nеw York: MсGraw-Нill. Ridlеy, М. 1986. Еuolutioп апd Сlаssifiсаtiсл:Thе Rеformаtioпof Сlаdism. Nеw York: Longman. Sсhlее'D. 1978' Villi Неnnig 191З-1976:Еinе ЬiographisсhеSkizzе.Еntomolсlgiса ()еrmапiса4:377-391. Sokal, R. R., аnd P. H. A. Snеаth.1963.Priпсiplesof Numеriсаl Tах
long fееt, a short Ьig ratio. To datе, thе rеmai found in assoсiation r giаnt Komodo drago dеnеd, firе-сraсkеd r. stonе tools wеrе ехса tools' and flaking dеl: Нomo florеsiепsis su1 Ьr.rtсhеrеdarrd сookt aЬilitiеs in suсh a smz Ьy an analysis of th. LB1's Ьrainсasе.A са thе Ьrain was higlrly r Ьеr of advanсеd fеаt pandеd in a rеgion t thought and for plаr сontradiсt thе suggе human аffliсtеd with

HobЬit (Homo floresiensis) ..HoЬЬit''

is thе niсknamе (aftеrJ. R. R. Tolkiеn's 1937 novеl, Tbe l7obbit) for a tiny skеlеton (сatalogеd as LB1)that rеprеsеntsa nеw human spесiеs (Нomo floresieпsis),whiсh lived from 95,000 to 12,000 yеars ago. This rеmarkаЬlе find wаs announсеd tn 2004 Ьy Miсhaеl Мorwood and othеr sсiеntists from Australia and Indonеsia. LB1 was ехсavatеd from 18'000yеar-old dеposits in Liang Bua, a сavе on thе Indonеsian island of Florсs. Thе nеarly сomplеtе skеlеton stands a littlе ovеr a mеtеr tall, and is bеliеvеd to rеprеsеnt аn adult woman. Thе skеlеton and fragmеnts of еlеvеn othеr individuals show tЬat Homo floresiепsis manifеstеd a miхturе o{ fеaturеs found in very еarly rеlativеs of humans (е.g., ...LuCУ,',datеd to ovеr 3 million yеars ago), ear\у Homo' morе rесеnt Homo еrес,t||s, and living pеoplе. LB].'s сomЬination of fеaturеs of thе Ьrain, tееth, shouldеr, wrist, pеlvis, lеgs, and fееt has not Ьееn found in any othег hominins, liv_ ing or еxtinсt. Homo florеsiепsishad vеry thiсk bonеs, rеlatively short lеgs'

Virtual skullof LB1 сomputеrtomоgrap еndoсast that rеprod

Нobbi phylogеnеtiс systеmatiсs was 3 8 ) .S o m е o f H е n n i g . s е n е m i е s s on гесognizingmonophylеtiс followегs quiсkly adoptеd thе nt сladists arguеd that thе Ьaary rеlationship Ьut thе most : data (Ridleу 1986). othеrs ,arsimonywas only onе of sеvеvоlutionаry rеlationships on rtesinspirеd Ьy Неnnig's rеvoran 50 yеars aftеr its original


long fееt, a short Ьig toе, a tiny Ьrainсasе, and an apе-sizеd Ьrain-to-Ьody ratlo. To datе, thе rеmains of twеlvе Homo florеsiensisindividuals havе Ьееn found in assoсiationwith faunal rеmаins of dwarfеd еlеphant-likeStegodoп, giant Komodo dragons, rаts. and Ьats. Сharrеd Ьonеs аnd сlustеrs of rеddеnеd, firе.сгaсkеd roсks wеrе also found in Liang Bua. High dеnsitiеs of stonе tools wеrе ехсavatеd from thе сavе' inсluding сorеs, anvils, rеtouсhеd tools, and flaking dеЬris. Bесausе of thеsе assoсiatеd finds, thе disсovеrеrs of Ilomo florеsieпsissuggеstthat thе spесiеsmadе tools, hul-rtеd,usеd firе, and Ьutсhеrеd and сookеd mеat. Although thе suggеstion of highеr сognitivе aЬilitiеsin suсh a small-Ьrainеdspесiеsrеmаins сontrovеrsial,it is sr'rpportеd Ьy an analysis of thе impгеssions of tlrе Ьrain that wеrе imprintеd insidе LB1's Ьrainсasе.A сast of thе Ьrainсasе (or еndoсast;sее figurе) rеvеals that thе Ьrain was highly сonvolutеd and uniquеly organized (wirеd),with a numbеr of advanсеd fеaturеs.For ехamplе, thе tips of thе frontal loЬеs wеrе еХpandеd in a геgion that is known to Ье impoгtant for пronitoгing intеrrral thought and for planning ahеad. Thеsе and othеr dеtails of LB1's еndoсast сontradiсt thе suggеstion Ьy a fеw rеsеаrсhеrs that it may Ье from a modеrn human affliсtеd with a pathology known as miсroсеphaly.

lnivеrsityof Illinois Prеss. nivеrsityof Сhiсаgtl Prеss. \еw York: МсGraw-Hill э Rеformаtion of Сlаdism. эgrаphisсhе Sk\zzе' Епtotпologiса : of Numеriсаl Тахonomу. San

-F.R.

сiеn's l937 novеl, The Hobbit) : p r е s е n t sa n е w h u m a n s p е с i е s 00 to 12,000 yеars ago. This Мiсhaеl Мorwood and othег I was ехсavatеd fгom 18'000rе Indonеsian island of Florеs. ) ovеr a mеtеr tall. and is Ье:lеton аnd fragmеnts of еlеvеn zsis manifеstеd a mixturе of tmans (е.g., ..Luсy,,' datеd to fecerftl-Iomo erесtus, and livof thе Ьrain, tееth, shouldеr, nd in any othеr hominins, liviсk Ьonеs,rеlativеly short lеgs'

Virtual skull of LB1 (..HoЬЬit'')that Was rесonstruсtеdusing thrее-dimеnsionаl сomputеrtomograplry.Thе skull has bееn flood-fillеdto rеvе:rla virtual endoсastthat rеpгoduсеsthе shaoеand othеr dеtailsof ..HоЬЬit's''Ьrаin.

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Нomologу Thе disсovеrу of Homo flсlresiепsis Was ехtгеmеly surprising Ьесausе it showеd tЬat Homo sаpiепs Was not thе only hсlminin arоund 18,000 yеars аgo (and Ьеforе),as had Ьееn widеly Ьеliеvеd.Sсiеntistsarе mixеd on thеir intеrpгеtationsaЬout whеrе rhis nеw spесiеsсаmе frоm. Somе tlrink that it is a dеsсеndant from Ьiggеr.Ьodiеd Homo еrесtusallсеstors that lrесamеdwarfеd aftеr migrating to thе island of Florеs. This hypоthеsis is in kееping with thе wеll-known island rulе, whеrеЬy largе аnimals Ьесonrеsmallеr (likе thе aЬovеmеntionеd Stegodoп\ and small animals Ьессlmеlargеr (е.g.'thе giilnt Kornodo dragons) on islands whеrе rеsourсеs arе limitеd. othеr workеrs Ьеliеvе that Homo florеsiепsismay lravе Ьееn dеsсеndеdfrom a small anсеstor' suсh as thosе in Luсy's genus (Аtlstrаlopithесus), аnd that its аnсеstors simply rеrnainеd small aftеr arriving On thе islirrrdof Florеs. Timе will tеll. в|BLloGRAPl{Y Brown,P.' T. Sutikna,tr4.J. Мorwоod, R. P. Soеjono,.|аtikmo, FJ.Y/. Saptсlmo, and R. А. Duс..2004.^ nеrvsmall-Ьоdiеd hominirrfrсlпlthе Lаtе Plеistoсеnе сlf F l o r е s I. n d o n е s i aN. а t ш ' е4 . 3 1 1 : 0 5 5 - t 0 6l . Fаlk, D., С. НildеЬolt,K. Srnith'М..|. Мtlrwood,Т. Srrtiknа, P. Bror,vn, Jatmiko, Е. W. Saptоmсl, B. Brutlsdеn,and F. Piroг.200.5.Thе Ьrainof LB|, Homсl 5. floresiепsis'SсiепсеЗО8:2"42_24 lv{orwood,М.J.. P. Brown'Jatikmo,T. Strtiknа'Е. W. Saptomo,К. Е. wеstaway' R. G. Rсlbегts, R. A. Dr"rе, T. Маеda' S. Wаsisttl'аnd Т. Diubiаntonсl. 200.5. Furthеrеvidеnсеfor small-bodiеd homininsfrоm tllе l,аtеРlеistсlсеnе оf Florеs. -D.F. I n d o n е s iN а .а I И r с4 3 7 : | О | 2 _ | 0 | 7 .

Homology Homology is onе of thе сеntral сonсеpts in Ьiology. It rеfеrs to thе similarity Ьеtwееnmorphologiсal сharaсtеrs'gеtlеs'and othеr Ьiologiсal rraits, suсh as Ьеhaviors,al-nongdiffеrеrrtspесiеs.Sоrnе of thе Ьеst-krrownехаnrplеsof homology arе (1)thе wings of Ьirds, thе arms сlf htlnlans, and tlrе forеlimЬs of othеr tеtrapods and (2) thе Ьony еlеmеntsin thе gill аrсhеs of sharks and thе thrее middlе еar Ьonеs (mallеus,inсus, аnd stapеs)in humans. Ir-rЬoth сasеs, thе similaгity bеtwееn сharaсtеrs is еstаЬlishеd indеpеndеntly of thеir sizе, shapе, and funсtion. This faсt is rеflесtеd in Riсhirrd owеn's dеfinition of a homologuе as ..thе samе orgаn in diffеrеnt animаls undег еvеry variеty of form and funсtion''' to Ье distinguishеdfrom an analoguе as ..a part Or Organ in onе animal whiсh has tlrе samе funсti
twееn dissimilar сhal of intеrmеdiatе forrт triЬrrtionof sinrilаrс ogy сritеria сapturе t Ьasеd on pattеrns of ' сlеotidе suЬstitutiorri sеquеnсеs.Bесelttsеo еvolurion, а fr.rrtlrе whiсh divеrgе as a rе paralogous gеnеs,wh Thе сonсеpt of hor tirnеs. Aristotlе fotrn irЬlе' and еvеn Ьеftlr analogy, thе idеаsсa dеЬatе Ьеtwееп Gес е a r l v 1 8 3 0 s ( s е еA p t Ьеst undеrstoсldin tL ments) аnd within th Gеoffroy arguеd fоr plarr of all аninrals,и rесognizеd thirt idеn arranging diftЪrеnt ft vidеs a rational systе thе rrotion of thе arс similаritiеs а1m()ng al In thе сontехt сlf t] tееnth сеntury' thе h thе oЬsеrvеd pаttеrn in thеir сommolt еvr> for thе rесonstruсtio phologiсal сritегia,еп asсеrtain homology r wаs Ьаsеd on thе аssl siп.rilarеmЬryolriсan ogy would soon run i glе сеll, it wаs not сlt samеnеssЬеtwееntrv amphibian lепsеs,сlf sion that thе original l proЬlematiс.Anothеr Thе rесognition that l ph ologiсal strtlсturеs tu.ееn Ьеhaviors wаs Today, thе homolс disсr.rssions withirr Ьi< irls аnd dеfinitionsof ]

Нoшologv ]еmеlysurprising Ьесausе tt lminin arrrund 18'000 уеars Sсiеlrtistsаrе пrixеd on thеir l е f r о m .S o m е t h i n k t h a t i t i s [сеstorsthаt Ьесarnеdwarfеd othеsisis in kееping with thе :сomеsmallеr(likе thе aЬovеLargеr(е.g.,thе giant Komodo l. othеr wсlrkеrs bеliеvе that om a small allсеstor' suсh as thаt its anсеstots simply rе_ .rt

tt

rеs. llmе wlll tеll.

о, Jаtikmo' Е. W. Sаptomo. and i r o n l t I l с l . а t е l ' l с i s t o с е n ео f . Sutiknа,P. Brоwn, Jatmiko, 5. Thе Ьrаin of L'B|, Homo W. Sirpttlrno,K. Е..Wеstаwurу' l, аnсlT. DjuЬiantono. 200-5. 'm thе Lаtе Plеistoсеnеof Florеs,

_D.F.

llogy. It rеfеrsto thе similarity othеr Ьiologiсal traits' suсh as ехamplеs of holе Ьеst-kr.rown thе forеlimЬs of and Еlruпrans, hе gill arсhеsof sharks аnd thе lpеs) in humans. In Ьoth сasеs, еd indеpеndеntlyof thеir sizе, R.iсhardowеn's dеfinition of a rnimals undеr еvеry variеty of .'a part oг organ tn anаloguеas аnothеrpart or оrgan in a difr is tlrat in ordеr to еstaЬlish thе that allow us tо dеtеrlf сritеri:-r pest, сompаrativе thс [n tеrs. today assеssmеnts; lr homology сritеria rrorphologiсallromology if two сharaсtеrs arе found in a turе-homology is morе likеly if s; (3) transition-homоlogy Ье-

twееlr dissilrrilarсlrarасtегsсan Ье еstaЬlishеdif thеy arе linkеd through a sеriеs of intеrпlеdiatе fornrs; and (4) sеvеrаrlсongruеnсе сritеria thаt сapttlrе thе distгiЬutiоп оf similaг сhаraсtегs in сlosеly rеlatеd spесiеs.Tlrе rnolесular homology сritеria сapturе thе similarity Ьеrwееn molесulеs, suсh аs DNA sеquеnсеs' Ьasеd on pattеrns of сommon dеsсеnt.Hеrе thе nцmbеr аnd thе position of nu. сlеotidе suЬstitution arе oftеn usеd as аn approхimation fоr thе сlosеnеssof rwo sеquеnсеs.Bесausе of thе high frеquеnсy of gеnе dupliсations in thе сoursе of еvolution, a furthеr distinсtion has to Ье madе bеtwееn orthologous gеnеs, whiсlr divеrgе as a rеsult of indеpеndеnt еvolution aftег a spесiation еvеПt' аnd paralogous gеnеs,whiсh divеrgе within ;.rspесiеsafter a gеnе dupliсatiorr еvеnt. Thе сorrсеptof homology datеs Ьaсk to prе-Daгwinian and prе_еvolutionary tirnеs' Aristotlе found similarity Ьеtwееn orgаnisms to Ье somеthing notiсеaЬlе, аnd еvеn bеfоrе Owеn fornrаlly dеfinеd thе соnсеpts of hоmоlogy and analсlgy,thе idеas сapturеd Ьy thеseсonсеptswеrе at thе hеart of thе famous dеЬatе Ьеtwееn Gеorgеs Сuviеr and Еtiennе Gеoffroy Saint-Hilаirе in thе еarly 1830s (sееAppеl 1987I. Whilе Сuviеr hеld that thе divеrsity of lifе is Ьеst undеrstoсldin thе сontехt of distinсt highеr groups (so-сallеdеmbrасhеmeпts) and within thosе groups Ьasеd on thе funсtional nееds of orgаnisms, Gеоffroy aгguеd for thе ехistеnсеof an undеriyirrgссrmmon organizational plan of all al-rimals,whiсh lrе сallеd univеrsal analogy or unity of rypе. Owеn rесognizеd tlrat idеntifying сorгеspоnding parts in diffеrеnt spесimеns and differеnt forms aссording to a nеstеd hiеrarсhy of similaritiеs proarrangir-rg vidеs a rаtional systеm for ordеring thе divеrsity of lifе' Hе also introduсеd thе notion of thе arсhеtypе as an abstraсt rеprеsеntаtionof thе undеrlying simiiaritiеs among e group оf organisms. In thе сontехt of thе Darwinian rеvolution of thе sесond half of thе ninеtееnth сеntury, thе homology сonсеpt ',vas historiсizеd. Thе еxplanation for tЬе oЬsеrvеd pattеrns of similarity Ьеtwееn organisms Was l1ow to Ье found in thеir сomlnon еvolutionarу history, and lromologiеs Ьесаnrе thе main tool for thе rесonstruсtion of thеsе phylogеrrеtiсrеlatiоnships. Along witЬ гпorphologiсal сritеria, еmbryologiсаlеvidеnсеwas also inсrе:rsinglyеmployеd to .Гhis prасtiсе asсеrtain homology rеlationships Ьеtwееn diffеrеnt struсturеs. wаs based on thе аssumption thаt sin-rilarstruсturеsshould also dеvеlop from similar еrnЬryoniс аnlagеn. Howеvеr, this program of еvolutionary morphology would soon run into diffiсultiеs.First, if аll struсturеsdеvеlop from a singlе сеll, it was ntlt сlеar whiсlr еmЬryoniс stagеsshould bе usеd to estaЬlish saftlеnеssЬеtwееll twсl adtrlt struсturеs. Sесond, rеgеnеrating tissuеs, suсh as amphiЬiаn lеnsеs'oftеn dеvеlop froш a diffеrеnt soufсе of сеlls. Thе сonсlusion that thе originаIand tlrе rеgеnеrаtеdlеns aге nоt hоmolсlgotlswas сlеarly proЬlеmаtiс.Anothеr appliсation of thе l-romologyсonсеpt was moге fruitfцl. Thе rесognition that Ьеhaviorаl pаttеrns сan Ье trеatеd thе samе wаy as morphologiсal struсturеsаnd that onе сan thеrеforееstaЬlishhomologiеs also Ьеtwееn Ьеlrаviors was thе foundation of thе sсiеnсе of еthology. Today, thе homоlogy сOnсеpt is again at thе сеntеr of sеvеral thеorеtiсal disсussionswithin Ьiology' This Ьas rеsultеd in a variеty of dif{еrеntproposаls аnd dеfinitions of Ьorrrologythat сan llе groupеd' aссording to thе rеsеarсh

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Hookеr quеstions thеy addrеss,into (1) historiсal homology сonсеpts аnd (2) Ьiologiсal homology сonсеpts. Нistoriсal homology сonсеpts arе prominеnt in phylogеny rесonstruсtion. Thе most widеly usеd approaсh, сladistiсs or phylоgеnеtiсsystеmatiсs,сharaсtеrizеsgroups of spесiеs(сladеs)Ьy thе prеs. еnсе of sharеd dеrivеd сharaсtеrs (synapomorphiеs).Thеsе synapomorphiеs arе historiсal h
y е a г е x p l o г a t o r y! o y a Е suЬsеquеntlyprоduсеd 1 8 4 7 , h еt r a v е l е dr о S i l еХotiс plants suсh as r! p е a n g a r d с n s .H е p u Ь l сamе assistant to his dirесtor, сontinuing К( of thе British Еmpirе. I ln \844, Darwin inf . . Е s s a y , 'i sеnr him thе two arguеd for many y

distriЬution of plants. anсiеnt lаnd сonnесtio q u е n t l y Ь е е ns u Ь n l е r g dеfеnding thе viеw thа еrrr hеmisphеrе, of wh sсattеrеdrеmnants. D:

thе oсеans Ьy flotatiol е v o | u t i o n i s m ,Ь u t е v е r thеory. Along with Сharlеs hе should tдkе аftеr гес i n r r o d u с t o r yе s s а vt o h p u Ь l i с е n d o r s е m е n t os t h е f a m o u s d е Ь a t еw i t t

thе British Assoсiation Was morе pеrsuasivе. Darwin and Hookе dесadеs.In 1878' Hoс of London to dеfеr-rdh Sphеrе. At thе samе tin o t h е r st h а r t h е m а i n s < г е g i o n s о f Е u г a s i аа n away from thе thеory Wаllaсе, anсl othеr su and oсеаtls.

Hookеr, Josеph Dalton (181'7-1911I Josеph Daltorr L{ookеr was a lеading Ьotanist of Viсtorian Britain and onе of Сharlеs Dаrwin's staunсhеst supportеrs. Hе was onе of thе first sсiеntists to Ье informеd of Darwin's thеory and playеd a lеading rolе in hеlping Darwin to formuiatе his idеas, еspесially in thе appliсation of еvolution thеory to Ьiogеоgraphy. Hookеr wаs Ьorn on Junе 30, 1817, thе son of Sir \WilliamJaсkson F{ookеr, who was dirесtoг of thе Royal Botаniсal Gardеns at Kеw. Не oЬtainеd an MD at Glasgow in 18З9 and latеr that yеar joinеd }i.МS Еrеbus on a four-

BIBLIOGRAPH

Alan, NI. 1967.Thе Hсlс I{ookеr,J. D. |845, Тhe Disсot,еrуShipsЕre Bros. | 8 5 5 .F l o r аl п d Iпdiа. I-ondon:\/ . 1 1860. FIorа Т,ls

Hrloker

I

mology сonсеptsand (2) ЬiologO g y с o n с е p t sа r е p r o m i n е n г i n [y usеd approaсh, сladistiсs or ls of spесiеs(сladеs)Ьy thе prеs_ orphiеs).Thеsе synapomorphiеs i а сonsеquеnсеof thеir phylogеl е r е s u l t i n gp h y l o g е n е t i сs y s t е m сharaсtеrizеdЬy a uniquе sеt of o t h е r h a n d , а I s o е m p h a s i z е s ,i n ry' thе dеvеlopmеntal origin of rеnotypiсstruсturеsarе sееn as a 1ram.As Girntеr.!7agnеr dеfinеd thе samе individual arе homolostraints,сausеd Ьy loсally aсting ation'' (Wagг'er 1989, 62). TЬe сapturеsthе distriЬution of hо_ intеndsto ехplain thе mесhanisl arе to Ье found in thе dеtails of nology сonсеpt is thеrеforе at thе thе rесеnt synthеsis of еvolution.

епch Biologу iп tbе Deсаdеs beforе gy. Novartis F-oundation аl Bаsis of Сompаrаtiuе Biologу. :nt and thе dеvеlopmеnt of thе 777-788. ,аtomу апd Phуsbklgу of the | Сollеgе of Sиrgeoпs. London:

nСept. АnпиаlReuietu "'\i}'.il',.

r.)

yеar ехploratory voyagе to Nеw Zea|and, Tasmania, and thе Antаrсtiс. Hе suЬsеquеntlyproduсеd a six-volumе survеy of thе Ьotany of thеsе rеgions. In 1847,Ьe travеlеdto Sikkim, Nеpal, and thе Еastеrn Himalayas, sеnding Ьaсk еxotiс plants suсh as rhododеndrons' whiсh soon Ьесamе favoritеs in Еuropеan gardеns. Hе puЬlisЬеd Florа Iпdiса in 1855, thе yеar in whiсh hе Ьесamе assistant to his fathеr аt Kеw. In 1865, hе suссееdеd his fathеr as direсtor, сontinuing Kеw's rolе as a lеading сentеr for thе есonomiс Ьotany of thе British Еmpirе. Hookег diеd in 1911. |n 1'844, Darwin informеd Hookеr of his idеas on еvolution and in 1'847 ..Еssay'' in whiсh his thеory was first dеsсriЬed in dеtail. Thе sеnt him thе two arguеd for many yеars ovеr thе thеory's impliсations for thе gеographiс distribution of plants. Нookеr Ьеliеvеd that dispеrsal had takеn plaсе ovеr anсiеnt land сonnесtions Ьеtwееn thе ехisting сontinеnts' whiсh had suЬsеquеntly Ьееn suЬmеrgеdЬy gеologiсal aсtivity. He was partiсularly aсtivе in dеfеnding thе viеw that thеrе had onсе Ьееn a grеat сontinеnt in thе southеrn hеmisphеrе, of whiсh Antarсtiсa, Australia, and Nеw Zea|and arе Ьut sсattеrеdrеmnants. Darwin arguеd instеаd for thе dispеrsal of sееds aсross thе oсеans Ьy flotation, winds, and Ьirds. Hookеr was at first skеptiсal of еvolutionism, Ьut еvеntually hе Ьесamе onе of thе еarliеst сonvеrts to thе thеory. Alоng with Сharlеs Lyеll, Hookеr advisеd Darwin on thе сoursе of aсtion hе should takе aftеr reсеiving Alfrеd Russеl Iil7allaсе'spapеr in 1858. Hookеr,s introduсtory еssay to Ьis Florа Tаsmаniаe of 1860 was onе of thе first major puЬliс еndorsеmеnts of thе thеory. Hе spokе aftеr Thomas Hеnry Huхlеy in thе famous dеЬatе with Bishop Samuеl WilЬеrforсе at thе oxford mееting of thе British Assoсiation in 1860, and somе obsеrvеrsthought his сontriЬutiоn was morе pеrsuaslvе. Darwin and Hookеr сontinuеd to dеЬatе Ьiogеography in thе following dесadеs.In 1878, Hookеr usеd his presidеntial addгеss to thе Royal Soсiеty of London to dеfеnd his thеory of an anсiеnt сontinеnt in thе southеrn hеmisphеrе. At thе samе timе' hе еndorsеd thе viеw favorеd Ьy Darwin and many othеrs that thе main sourсе of morе highly еvolvеd spесiеs Was thе northеrn rеgions of Еurasia and North Amеriсa. Lаtеr in his lifе' he Ьеgan to Ьaсk away from thе thеory of sunkеn land Ьridgеs' undеr prеssrrrеfrom Darwin, !Иallaсе, and othеr supportеrs еspousing thе pеrmanеnсе of thе сontinеnts and oсеans. BlвLIoGRAPHY

lt of Viсtorian Britain and onе of Was onе of thе first sсiеntists to a lеading rolе in hеlping Darwin pliсation of еvolution thеory to

Alan, M. 1967.Тhе Hookеrsof Kеш' London:МiсhaеlJosеph. Hookеr,J. D. 1845. Thе СrуptogаmiсBсltапуof the Апtаrсtiс Voуаgеof H.М. DisсouеrуSЙlpsЕrеЬusапdТerror iп thе Yеаrs18']9_4З.6vols.London:Rееvе Bros. 1855.Florа Indiса:Bеiпg а SуstеmаtiсАсcouпt сf thе Plапts of British

n of Sir \WilliamJaсkson Hookеr' ardеns at Kеw. Hе oЬtainеd an . joinеd T1МS Еrеbus on a four-

-P.J.B.

.!И. Irtdiа. London: Pamplin. 1'860. Florа Tаsmапiаe. Londоn: L. Rееvе.

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Нost PаrаsitеЕuolution

Host paгasiteеvolution Parasitеs сan ехеrt natural sеlесtion on host populations, and viсе vеrsa' rеsulting in сhangеs in allеlе frеquеnсiеsovеr timе and hеnсе еvolution. Рarasitеs and lrosts сan also ехеrt rесiproсal' similtanеous natural sеlесtion on еaсh othеr, rеsulting in аllеlе frеquеnсy сhangеs in Ьoth partnеrs and hеnсе сoеvolution. T.hеrеaге sеvеral aсtivе rеsеarсh programs in thе arеa of pаrasitе еvolution. Onе of thе most aсtivе arеas is on thе еvolution of pаrasitе virulеnсе. Thе rеsеaгсh program is nrainly еngagеd in answеring thе quеstion: !0hy do somе parasitеs makе thеiг hosts vеry siсk, whilе othеr parasitеs havе littlе еffесt on thеir hosts?Thе сonvеntionalwisdom in this arеa pгior to thе 1980s' еspесially in thе mеdiсal сon-lmunity' was that pаrasitеs should еvolvе to Ье inсrеasingly ..good.of.thеЬеnign so as not to harm thе host population. But this kind of spесiеs'' rеаsoning was rеiесtеd in tlrе 1980s Ьy thеorеtiсаl biologists.Thеy showеd that parasitеs should in faсt Ье undеr natural sеlесtion to maхimizе thеir own transmission to thе nехt host, without rеgаrd to thе еffесts on thе host population. In somе сasеs' transmission is rrraхimizеdby гаpid rеpliсatiоn within thе host, lеading to high ratеs of host mortality (and/or morЬidity). Suсlr an outсomе might Ье еxpесtеd, for ехamplе, in parasitеs that aге еasily movеd Ьеtwееn hosts Ьy vесtors' suсh as nrosquitoеs(е.g.,malaria). Hеnсе, еvеn if thе host is inсapaсitatеd Ьy disеasе, thе infесtious propagulеs сan Ье movеd Ьеtwееn hosts Ьy thе vесtors (or, similаrly' Ьy watеr). Irr gеnеral' if disеasе transmission doеs not геquirе a hеalthy, moЬilе host, sеlесtion may favor parasitеs that rеproduсе rapidly at thе host's ехpеnsе. Studiеs on thе еvolution of parasitе virulеnсе havе important impliсations for human hеalth. For ехarnplе, mеdiсal pгaсtiсеs that inсrеasе thе еasе of disеasе sprеad not only inсrеasе thе numЬеr of infесtеd hosts, Ьut thеy сan аlso rеsult in sеlессion fоr nrorе virшlеnt strains' Similarly, pаrasitе stгains thаt arе most rеsistant to antiЬiotiсs will Ье favorеd Ьy sеlесtion. If, for ехamplе, antibiotiсs arе admistегеd in low dosеs that arе not suffiсiеnt to kill thе еntirе parasitе population witЬin еaсh host, thеn thе antiЬiotiс rеsistant strains will inсrеasе in frеquеnсy. Thе еvolution of antiЬiotiс rеsistanсеis a major proЬlеm in human hеаlth and in thе hеаlth of domеstiсatеdanimals; it rеPгеsеntsa сlassiс сasе of rаpid еvolutionary сhangе. Parasitеs are also undеr natural sеlесtion to еvadе dеtесtion and еlimination Ьy thеir hosts. Сonvегsеly, hosts arе undеr natururlsеlесtionto find and kill thеir parasitеs.Мutatiolrs that inсrеasеthе infесtion Suссеssof parasitеs will Ье favorеd Ьy natural sеlесtion,whilе mutations that inсrеasе dеtесtion Suссеssof pаrasitеs Ьy hosts will Ье sinrilaгly favorеd. This сan lеad to two ..arms raсе,'' Ьеntypеs of сoеvolutionary intеraсtions.In onе typе, сallеd an еfiсiаl mutations in thе parasitе population swееp to fixation; mеaning that thеy rеplaсе thе altеrnativеirllеlеsin the population, followеd Ьy similar suссеsssfulswееps of mutations for dеfеnsеin thе host population. In anothеr gеnеral typе of сoеvolutionary intеraсtion, Ьеnеfiсialаllеlеs do not go to fixation. Неrе hсlst allеlеs intеraсt with urllеlеsat othеr host loсi'

and thеir сombination hоst thеn indеntifiеs pa up natural sеlесtionfoI host gеnotypеs for sеl{ Ьесomе сommon' thе} typеs, driving thеm do. thе rnost сommon gеn( fеrеnt multiloсrrs paras lation in Ьoth host аnd g е n е r i сd i v е r s i t уi n b o r now known as thе Rес Ьoth host and parasitе; samе plaсе. (Thе namе Aliсе in Lеwis Сarroll'r tаkеs all thе running 1'с hypothеsis сurrеntly s m a i n t е n a n с еo f g е n е t i to bе highly polymorpt t h a t a t t е m P tt o е х p l a i r not morе сommonly rе basiс idеa herе is that p as thеy Ьесomе loсally u a l p o p u l а t i o ni n t h е s Parasitеs havе also rеproduсti
turing. Finally, parasitеshа havior in ordеr to еnh nеw hosts. For ехаnrр d u с е Ь е h а v i o r si n t h е i еatеn Ьy prеdators.Bu prеdator is also anoth t h е p а r a s i t е s u г v i v е s; sumption. Thus it wou ra1sеlесtionto еnhаnс onе of thе hosts in thе

BIBLIOGRAPH

Bеll' G. !982. Тhе Маst Bеrkеlеy:Univегsit Е w a l d ,P . W . \ 9 9 4 .Е u o

Hсlst Pаrаsite Еuolutioп

ulations,and viсе vеrsa' rеand hеnсе еvolution. Parаlnеous natural sеlесtion сln in Ьoth partnеrs and hеnсе ] е а r е аo f p а r a s i t ее v o l u t i o n . lf parasitеvirulеnсе. Thе rе. thе quеstion: !Иhy do somе parasitеshavе littlе еffесt on prior to thе 1980s' еspесially uld еvolvе to Ье inсrеasingly ..good-of-thеrt this kind of thеorеtiсal Ьiologists. Thеy -rturalsеlесtionto maximizе . rеgard to thе еffесts on thе rximizеdЬy rapid rеpliсаtion rortality (and/or morbidity). е, in parasitеs that arе еasily ritoеs(е.g.'malaria). Flеnсе, infесtious propagulеs сan Ье , Ьy watеr). In gеnеral, if disэilе host' sеlесtion may favor Insе. h a v е i m p o r t a n ti m p l i с a t i o n s сеs that inсrеasе thе еasе of infесtеd hosts, but thеy сan s . S i m i l a r l y .p a r а s i г еs t г а i n s orеd Ьy sеlесtion. If, for еxгhat arе not suffiсiеnt to kill t h е n t h е a n t i Ь i o t i сг е s i s t а n t l o f a n t i Ь i o t i сr е s i s t a n с еi s a h of domеstiсatеdanimals; it langе. : v а d еd е r е с t i o na n d е l i m i n а natural sеlесtion to find and infесtion suссеssof parаsirеs rtionsthаt inсrеasе dеtесtion rvorеd. This сan lеad to rwo :,сallеd an ..arms raсе,'' Ьеn:еp to fiхation, mеaning that гion, followеd Ьy similar suсrost population. еraсtion' Ьеnеfiсialallеlеs do ith allеlеs at othеr host loсi,

..sеlf.'' and thеir сomЬination yiеlds a multiloсus gеnotypе thаt dеfinеs Thе ..sеlf'' host thеn indеntifiеs parasitеs that do not matсh its gеnotypе. This sеts up natural sеlесtion for parasitе gеnotypеs that сan infесt thе most сommon host gеnotypеs for sеlf. Howеvеr, onсе thеse suссеssful parasitе gеnotypеs Ьесomе сommon' thеy imposе sеlесtion against thе most сommon host gеnotypеs, driving thеm down in frеquеnсy. Thеn a nеw host gеnotypе Ьесomеs thе most сommon gеnotypе' and thе sеlесtion on parasitеs сhanges to a diffеrеnt multiloсus parasitе gеnotypе. In thеory, this sеts up a сontinous osсillation in Ьoth host and parаsitе gеnotypеs' whiсh would funсtion to maintain gеnеtiс divеrsity in Ьoth thе host and thе parasitе populatiоns. Thе thеory is now known as thе Rеd Quееn hypothеsis, Ьесausе it would sееm as though Ьoth host and parasitе gеnotypеs arе running as fast as thеy сan to stay in thе samе plaсе. (Thе namе сomеs from thе famous rеmark Ьy thе Rеd Quееn to Aliсе in Lеwis Сarrolr|'sThroиgh the Looking G/ass: ..Now, berе, you seе, it takеs all thе running уoxl сan do, to kееp in thе samе plaсе.'') Thе Rеd Quееn hypothеsis сurrеntly stands as onе of thе Ьеst-supportеd thеoriеs for thе maintеnanсеof gеnеtiс divеrsity аt disеasе-rеsistanсе loсi, whiсh arе known to bе highly polymorphiс. It also stands as onе of thе Ьеst-supportеd thеoriеs that attеmpt to ехplain why asехual produсtion of all-fеmalе offspring doеs not morе сommonly rеplaсе sехual rеproduсtion in natural populations. Thе basiс idеa hеrе is that parasitеs would imposе sеlесtion against asехual сlones as thеy Ьесomе loсally сommon' and thus prеvеnt thе еlimination of thе sехual population in thе short tеrm. Parаsitеs havе also Ьееn impliсatеd as a sеlесtivе forсе in thе timing of rеproduсtion in somе animals. Thе idеa is that аnimals would Ье undеr parasitе.mеdiatеd natural sеlесtion to rеproduсе at a smallеr sizе and youngеr agе in populations thаt arе suЬjесt to a high risk of infесtion Ьy virulеnt parasitеsthan populations that arе аt rеlativеly low risk of infесtion. Thе rеason is that dеlaying rеproduсtion in high.risk populations might rеsult in thе produсtion of fеwеr offspring' if, in faсt' thе host Ьесomеs infесtеd Ьеforе maturing. Finally' parasitеs have also Ьееn impliсatеd in thе manipulation of host Ье. haviоr in ordеr to еnhanсе thе transmission of thеir infесtivе propagulеs to nеw hosts. For еxamplе, sеvеral studiеs havе now shown that parasitеs induсе Ьеhaviors in thеir hosts that inсrеаsе thе likеlihood that thе host will Ье еatеn Ьy prеdators. But this is only known to oссur in parasitеs for whiсh thе prеdator is also anothеr host in thе parasitе's lifе сyсlе; аnd it is known that thе parasitе survivеs and еstaЬlishеsitsеlf in thе nеw host following сonsumption. Thus it would аppеar that somе parasitеshavе rеspondеdto natural sеlесtion to еnhanсe thеir ratеs of transmission Ьy altеring thе Ьеhavior of onе of thе hosts in thеir multihost lifе сyсlеs. BIBLIOGRAPHY Bеll, G. 1982. Тhе Маstеrpiесеof Nаturе: Tbе Еuolиtioп апd Gепеtiсsof Sехuаlitу. Bеrkеlеy:Univеrsityof Сalifornia Prеss. Еwald' P. w. |994. Еuolutioпof IпfесtioиsDisеаsе.Oxford: Oхford UnivеrsiryPrеss.

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Нrdу Garrеtt, L. 1994. Thе Сomiпg Plаguе:Nеtulу ЕmеrgiпgDisеаsеsiп а World Оut of BаIапсе.Nеw Yoгk:Farrar,Strausаnd Giroux. Nееsе,R. -N4., and G. С. Williaпls.,|'994. Whу \WеGеt Siсk.Nеw York: Randсlm Нousе. Zimmеr, с. 2000. PаrаsitеRех: Iпsidеthе Bizаrrе \|y'orld of Nаturе'sNItlst -С.L' DаngerousСrеаtures.Nеw York: FгееPrеss.

Hгdy, SaгahBlaffеr (ь.1946) Sarah Blaffеr Нrdy is onе of Amеriса's most еminеnt anthropologists and a mеmЬеr of the National Aсadепry of Sсiеnсеs.Arr anthropologist and primatologist Ьy training, shе works within thе Ьroаd framеwork of soсiobiologiсal thеory, to whiсh shе has madе signifiсаnt сontributions. Hrdy is most wеll knowrr for сalling attеntion to thе various еvolutionarY stratеgiеsusеd by fеmalе primatеs, whiсh hаs Ьrought a radiсal shift away from primatologists' traditional foсus on mаlеs as thе primе soсial асtors. Morе rесеntly, Нrdy has rееvаluatеd thе rolе of mothеrs and thеir геlationsЬip to thеir сhildrеn. Although shе rеliеs hеavily on thе ..сoпtparativе mеthod'' сеntral to soсioЬiology, whеn shе writеs aЬout sеx diffеrеnсеsНrdy is an еquаl-opportunity сritiс of Ьoth fеminists foг ignoring Ьiology and of еvolutionary psyсlrologistsfor ig. noring soсial histоry. Нrdy was Ьorn in 1946 to a wеalthy Southеrn family. Slrе graduatеd from Radсliffе with a BA in 1969. It was in a Harvard anthropology сoursе that shе пrеt hеr futurе husЬand, Daniеl Hrdy (a Сzесh nаmе), whom shе mar' riеd in 197\ Ьe lаtеr Ьесaпrе a mеdiсal doсtor. Whilе rеaring thеir thrее сhildrеn, shе Ьесamе inсrеasingly foсusеd on thе nееd to updatе Attaсhmеnt Thеory with a viеw to thе еvolution of еarly hominids as сooреrativе Ьrееdеrs. (Aссording to this thеory, dеvеlopеd Ьy Iohn BowlЬy, еarly attaсhmеnt to сarеgivers is сruсial for infants' normal soсial and еmotional dеvеlopment.) Hrdy entеrеd graduatе sсhool in аnthropology in 1970, аЬout thе samе timе that Еdward o. !Иilson was Ьеginning to writе Soсiobiologу: Thе Neш Sупtbesis;sЬе сomplеtеd lrеr PhD in 1975, tЬe yеar it was puЬlishеd' Irvеn DеVсlrе's first fеmalе studеnt, shе was hеavily influеnсеd Ьy Wilson and Ьy Robеrt Trivеrs. All thrее supеrvisеd hеr fiеldwork on thе Нanuman langurs of India, puЬlishеd as Thе Lаngurs rlf Аbu: Femаlе аnd МаIe Strаtegies of Reproduсtion ln 1977. Shе had initially undеrtakеn hеr rеsеarсh on infantiсidе Ьy adult malеs in langurs, Ьеliеving it was a patlrologiсal rеsponsе to сrowding. During hеr first fiеld sеason shе had to disсard that hypothеsis.Infantiсidal Ьеhavior was highly sеlесtivе:malеs targеtеd infants Ьorn to fеmalеs thеy hаd not matеd with. Rесоgnizing thаt fеnralеswеrе fаr from pirssivе, Hrdy Ьеgan to study fеmalе сountеrstratеgiеs. For еxamplе, Ьy mating with multiplе malеs bеforе thеy usurpеd сontrol of thе tгoop, fеrтialеsstrovе to {orеstallinfantiсidе latеr сlп. .Womап In hеr nехt Ьook, The Thаt Nеuer Еuoluеd ( 198 1 ), Hrdy provoсa. tivеly kеpt fеmalеs сеntеr stagе and inсorporatеd thе primatе origins of pаtriaгсhy in hеr analysis. Mеanwhilе, thе work on infantiсidе rеmainеd

сontrovеrsiаl, inspiгin1 lowеd Ьу lnfапtiсidе: с o е d i t е dw i t h G l е n r l I ' t е r е s t е di n d i l е m m а s с dееp into prеhistoгy. S options that mothеrs 1 m o t h е r s . ' r o n е g l е с г. . group who assist a mо pеarеdin 1999,l,ibrаt Inсrеаsinglv drarд.nttr Dahlеm.!Иorkshop rеp Hrdy's Ьoсlks hаvе l idеas of infantiсidе wе ogy сommunity, in 20

pologiсal Assoсiation otrtstanding Сontri Ьut Hrdy hеld thе positr Cаliforniа :rt Dаvis fro

Еnrеrita, slrе сontinuеs itorial Ьoardsof Еuolи hеr husЬаnd livе ir.rСа and sцstainаЬlеagriсu

BIBLIOGRAPHY

С a г t е r ,с . s . ' l , . A h n с г t сс1 and N. S.lсhsеr, Prеss. H r u s Г а t е r(,i . . а l l d \ . H r . ЕuolutioпаrуPеrsp H г d y ,S a r a hB h f f с r ' 1 9 7 ()а of Rеproduсtiolt. rvithnеw prt еditiоr-r 198| [1999l.Тll UnivегsityPrеss'( l9 1 9 9 9 .М o t h c rN Nеw York: Pаnthе w.с WсЬ раgе.Ьttp://wrr

Hutton, Jamеs(1

Jamеs Hutton, а Sсot thе fathег of gеology аnd was a mаjor figur rar1,of David Humе a ory of gеology as lvеll l hе arguеd-against th bееn formеd Ьy prесr hot and tl-rat roсks a

Нuttott liseаsсs iп а World Оut of A. Nеw York: Random of Nаturе'sМost

-С.L.

:lt аnthr()pologistsаnd a rtlrropolоgistand primam е w o r ko f s o с i o Ь i o l o g i :riЬutions.Hrdy is most lutionary stratеgiеsusеd ift away from primatoloгors.Moге rесеntly' Flrdy ship to thеir сhildrеn. Alod'' сеntrirl to soсioЬiol. r е q u а l - r l p p o г t u n i tсyr i t i с nаr1,psусhologistsfoг ig_ nily. Shе graduatеd from 'nthropology сoursе that n a m е ) ,w h o m s h е m a r Vhilе rеaring thеir thrее еd to updаtе Attaсhmеnt ids as сoopеrativе ЬrееdiowlЬy, еarly аttaсhmеnt and еmotionir1dеvеlop_ л 1'970,about thе samе э Soсiobiologу: Thе Nеtu r it was puЬlishеd. Irvеn .Wilson еnсеd Ьy and by rn thе Нanuman langurs е апd Маle Strаtegies of t h е r r е s е а г с ho n i n f a n t i pathologiсal rеSponsе tс) sсardthat hypothеsis. lnэd infаnts boгn to fеmalеs s wеrе fаг from pаssivе. еxamplе,Ьy mating with trоop, fеmalеs strovе to i (198\), Hrdy provoсahе prinratе origins of paon infantiсidе rеmainеd

сontrovеrsiаl, inspirirrg thе first intеrnational сonfеrеnсе on thе topiс, followеd Ьy lпfапticidе: Сompаrаtiuе апd Ьuolutioпаr\' Perspеctiuеs (1984), сoеditеd with Glеnn Нausfatеr. By thеn, Hrdy had Ьесomе inсrеasingly intеrеstеdin dilеmmas сonfronting working mothеrs thrrlughout history and dееp into prеhistory. Shе sеt out to ехaminе aсross spесiеs and сulturеs thе options that mothеrs havе с-rтployеd,from sееking thе assistаnсеof ..allomothеrs'' to nеglесt and ;rЬаndonmеnt. (Allomothеrs arе mеmЬеrs of a gгoup who assist a mothеr in rеагing hеr infant') rJ?hеrrМorДеr Nаturе appеarеd in1999, I-illrаrу Jсlurпаl namеd it onе of tlrе Ьеst Ьooks of thе yеar. lnсrеasingly drawrr to thе quеstion of infant nееds, irr 2005 shе сoеditеd а Dаhlеm !Иorkshop rеpoгt on attaсhmеnt and Ьondirrg. Hrdy's Ьooks havе Ьееn translatеd into sеvеral lаnguagеs.Although hеr idеas of irrfantiсidеwеrе lоng rеgardеd with suspiсion within thе anthropology сommunity, in 2О02, at thе annual mееting of the Amеriсan Anthropologiсal Assoсiation, Мother Nаture was awardеd thе Howеll Prizе for outstanding СontriЬution ir-rBiologiсal Anthropology. Hrdy hеld thе positiorr of Profеssor of Anthropologу ilt thе Univеrsity of Сaliforпia at Davis from l984 to lrеr еarly rеtirеmеntln I996' As Profеssor Еmеritа, sirе сontinuеs сloirrgrеsеаrсh,writing Ьooks, aпd sегvil-rgorr thе еditorial boards of Еt,сllutiсlпаrу Aпthropologу anсl Нutпап Nаturе. Hrdy and hеr husЬand livе in СаliГoгnia, whеrе thеy arе involr,еdin hаЬitat rеstoration and sustainaЬlеagriсtrlturе. BIBLloGRAPнY Сartеr'с. s.' L. Ahnеrt,K. Е. Grossrтann,S. B. Hrdy, М' Е. LamЬ,S..W.Porgеs, and N. Saсhsеr,еds.2006.Аttасbmепtапd Boпdiпg.Сambridgе,MA: МIT Prеss. Hausfatеr,G., and S. Hrdу' еds.[1984]2О08.Iпfапtiсide: Сtлпpсlt'tttiue апd Еuоlutioпаrу Pсrspссti uеs, Nеrv Brunswiсk'N.|: Aldinе Transaсtiol-l. Нгdy, SaralrBlаffег.1977 L1980|.Тbе Lаltgttrstlf Аbtt: Fсnlаlеапd NIаlеStrаtеgies сlf Rеprсldttсtiсlll. СаrrrЬridgе, МA: Hаrvаrd Univегsit1. Prеss.(1980,рapеrЬaсk е d i t i o nw i t h r l е r rp' r е i ; r с с . ) 1981 [1999].TЬс WomапТhаt NеuerЕuoluеd.СarnЬгidgе, N{A:Harvard UnivеrsityPrеss.(l999, papеrЬaсkесlitiсln with nеrvprе[асе') 1'999.Мl>tbеrNdtut€ : А Histсlrуof МotЬеrs,Iпfапtsапd Nаturаl SеIесtioп. Nеw York: Pantlrеоrr. \Иеh рagе. h ttp://www'сitrоna.соm/sаrаhЬhrdy.htm.

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Hutton, Jamеs(|726-1797) JаrrrеsHrrttсln, a Sсottish-Ьorrrс]oсtоr and gеntlеmаn firrtnеr' is сonsidеrеd thе fathеr of gеology irr Britain. Hе livеd пruсh of his latеr lifе in ЕdinЬurgh and was a major figurе in thе so-сallеdSсottislrЕrrlightеnmеnt.A сontеmporarу of David Humе аnd Adam Smith, hе сhampionеd Ьосh thе Plutonist thеory of gеologyas wеll аs thе mеthodologyof uniformirаrianism.As a Plutonist, hе arguеd-against thе so-сallеd Nеptunists, who thor"rghtthat thе world had Ьееn formеd Ьy prесipitаtiсln from Watег-that thе сеntеr of thе еarth is vеry hot and that roсks arе formеd Ьy moltеn lava pushirrg up to thе surfaсе,

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Huttoп whеrе it solidifiеs. At thе samе timе' as a uniformitarian, hе arguеd thаt thе way to undеrstand gеology is Ьy аssuming that сausеs today arе thе samе as thosе of yеstеrday,аnd thаt givеn еnough timе' gеologiсal formations сan Ье сrеatеd natuгallу. Hutton puЬlishеd thеsе idеas irr a massivе two-volumе work titlеd Theorу of the Еаrth (1795I, a trеatisеwhosе lеngth was ехсееdеdonly Ьy its oЬsсurity. Fortunatеiy a followеr, Jol.rnPlаyfair, puЬlishеd a moге rеadily aссеssiblе vеrsion in 1802, and Hutton's gеologiсal position Ьесamе rесognizеdand еstablishеd. Howеvеr, iг wаs opposеd Ьy thе nrorе popular thеorizing of Gеorgеs Сuviеr (181З)' who supposеd that thеrе aге many сonvulsions in еarth histoгy, and it was not until 18З0 that Hutton's uniformitаrianism found a major сhampion against thе Frеnсhmаn,sсatastrophism.T'his сamе in thе rhrее-volumе Priпсiples of Gеologу Ьy Сhаrlеs Lyеll' probаЬly thе work that was thе grеatеstinfluеnсеon thе young Сharlеs Darwin. Fronr thе viеwpoint of еvolutionary thinking, Hutton's importanсe liеs in thе wаy in whiсh hе ехtеndеd еa[th history. Не famоusly spokе of thе woгld аs showing ..no vеstigе of a Ьеginning' no prosPесt of an еnd'' (1788, 304), and to Plaуfair сlaimеd that on looking at stгata' ..thе mind sееmеdto grow giddy by looking so far into thе aЬyss of timе.'' (Playfair 1805) oЬviously, tlris kind of thinking wаs going against ЬiЬliсal histоry rеаd litегаlly. Although Hutton was aссusеd of athеism, morе proЬaЬly hе was (like many latе'еightеenth-сеnturythinkеrs) morе of a dеist, onе who sееs thе glory of God in his urrЬrokеrrlaws. Although historiсally insignifiсant in thе sеnsеthat this Ьеliеf hе hеld was not an influегlсеon lаtеr thinkers, it is proЬaЬlе rhat FIutton sharеd with othеrs of his day (notaЬly Еrasmus Darwin, thе grandfathеrof Charlеs) аn inсlination to son]е kind of trilnsformism in thе oгganiс world. Indееd,thеrе аrе Passagсsin his writing that sound almost likе an antiсipation of natural sеlесtiоn' Hе wrоtе ln Ьis Priпсiplеs of Kпoшlеdgе that ..if an organisеd Ьody is not in thе situation and сirсumstanсеsЬеst adaptеd to its sustеnаnсеand propagation, thеn' in сonсеiving аn indеfinitе variеty аmong tlrе individuаls of that spесiеs,wе must Ье assurеd,that, on thе onе hand' thosе whiсh dеpart most from the bеst adaptеd сonstitlltion, will Ье thе most liaЬlе to pеrish, whilе' on thе othеr hand' thosе organisеd Ьodiеs, whiсh most approaсh to thе bеst сonstitution for thе prеsеntсirсumstanсеs,will Ье bеst adaptеd to сontinuе' in presегving thеmsеlvеsand multiplying thе individuals of tlrеir raсе'' (Hutton 1794, З)' Сlеarly muсh influеnсеd Ьy thе work that hе and otlrеrswеrе doing on animal and plant Ьrееding in thе advanсеmеnt of Ьеttеr agriсulturе, Hutton notеd that dogs suгvivе thanks to ..swiftnessof f
half of thе ninеtееnth сс Spесiеs to tцrn suсh idеa вlвLloGRAPHY

Сuviеr,G. 1813. Еssаусln !И. Blaсkwood. H u t t o n 'J . 1 7 s s .T h е о r yo f thе сomposition,disso Trапsасtioпsof the Rс | 7 9 4 ,А п I п u е s t i of Rеаsсlп,|rom Sепsе T. Сadеll. |795 . Тbеorу o|.t| .!Иilliаm Сrеесh. L у е l l .C ' l 8 3 0 - l 8 3 j . Р r l l l Formеr Сhапgеsiп th' Оpеrаtioп.З vols.Lol Plaуfair,J. 1802.]Ilustrаt .!7illiam Сrеесh. t 8 0 5 .B i o g r а p h i Тrаltsаctioпsof thе R' Rеpсhесk,J. 200з. Тhе М, thе Еаrth,sАпtiqнitу Rudwiсk,N4.J.S. 2005.B СhiсzrgoPrеss.

Huхley,Julian S. (1

Jшlian Sorеll Нuхlеy w Britain's intеlligеntsiа.l t h е 1 9 3 0 s a n d 1 9 4 0 s .l thе puЬliсat\on o| Еt'ol tratеd attеntiorr onto СI

lеy promotеd еvolutiоn of spесiation, whilе al Huxlеy's сontriЬutions fесtious еnthusiasm a1 sсаttеrеdсonсеptsor iс Born in Lоndon, Hu l е g е ,o x f o r d ( 1 9 0 6 ) 'w (zoology).Hе spеnt tht Ьook, Thе lпdiuiduаl il а sсiеntifiс aссorrnt of (

Сrеаtiсe Ьy thе Frеnсh fondnеss for thе vitalis sсiеnсе).In thе сoursе tlrе timе Ьеtwееn thе B ..arms of a Ьiologiсal

Hихlеl', Juliап S. mitarian.he arguеd that thе эausеstoday arе thе san-lеas qеologiсalformations сan Ье

half of thе ninеtееnth сеntury. It took Сharles Darwin in Оп tbe origiп of Spесiesto turn suсh idеas into а full tlrеory of еvolution.

l-volunrе work titlеd Thеorу ; ехсееdеdonly Ьy its oЬsсui s h е dа m o r е r е a d i l y a с с е s s i ition Ьесarlе rесognizеd and morе pоpular thеorizir-rg of :rеarе lnаny сonvuIsionsin H u t r o n ' s u n if o г m i t а r i а n i s m r's сatastrophism.This сamе Сharlеs Lyеll, proЬаЬly thе rg Сh:rrlеsDarwin. Hutton's importanсе liеs in famously spokе of thе world ) е с to f a п е n d , ' ( 1 7 8 8 , 3 0 4 ) , l, ..thеmind sееmеdto grow , (Plаyfаir 1805) oЬviоusly, al history rеad litеrally. AlproЬaЬly hе was (like many t, onе who sееs thе glory of

Сuviеr,G. 1813. Еssа\'oп thе Theorуo|.thе Еаrth.R. Kеrr' trans.ЕdinЬurgh: .W. Blaсkwood. Huttoll'J. 1788.Thеoryof thе еarth;Or an invеstigation of thе laws oЬsеrvaЬlе in thе сomposition'dissolution,and rеstorationof lаnd upon thе gloЬе. T'rапsасtioпs of thе Roуаl Soсiеtуof Еdiпbиrgb 1, no. 2: 209_304. |794. Ап lпuestigаtioпoi thе Priпсiplеsof Kпou,lеdgеапd of t|lеProgrеss of Reаsoп,from Seпsеto Sсiепсеапd Philosophy.ЕdinЬurgh:A. Strаlranand T. Cadеll. 1795. Тhеorу of thе Еаrth, шith Proofs апd ]llиstrаtiozs.ЕdinЬurgh: williаm Сrеесh. Lyеll, С. 1830_1833.Priпсiplеsof Gеologу:Bеiпg аn Atteпт?ttrl Ехplаin tbс Formеr Сhапgesiп thе Еаrth's Surf,lсеbу Rеfеrепсеto СаusеsNott''ilt ()pеrаtion.3vols.London:John Мurray. Playfair'J. \802. Illustrаtionsof thе Huttoпiап Thеorу of thе Еаrth. ЕdinЬurgh: \filliam Сrеесh. 1805.Biographiсalaссountof thе latеDr. JamеsLluttonF. R. S. Еdin. .]-rапsасtioпs of thе RrlуаISoсiеtуof Еdiпburgh 5, no. 3: 39_99. Rеpсhесk,J. 2003. Thе Мап Vlho Ftluпd Time:Jаnlеs Нuttсlпапd thе Disсouеrуof the Еаrth,sAпtiquitу'London:Simonаnd Sсhustеr. Rudwiсk,M.J.S. 2ОО5.Bиrstiпgthe Limits of Time.Chiсago:Univеrsityof -М.R. СhiсagоPrеss.

е that this Ьеliеf hе hеld was гhatHr.rttonsharеd with oth_ ndfathеrof Сharlеs) an inсlianiс world. Indееd, there arе Lnantiсipatiоn of natural sе..if e thаt an organisеd Ьody daptеd to its sustеnanсеand ariеty among thе individuals е onе hand, thosе whiсh dеzill bе tlrе most liaЬlе to pеr'odiеs,whiсh nrost appгоaсh rnсеs,will bе Ьеst adaptеd to ying thе individцals of thеir

Huxlеy,Julians. (1887_|975)

rnd othегswеrе doing on an'f Ьеttеr agriсulturе, Нutton foot and quiсknеss of sight'' sе nесеssaryqualitiеs' would ,o еmployеdthеm in grеatеSt ain, to prеsегvе thеmsеlvеs, |vеr'onе slrould not rеad too .ostсommonplaсе in thе first

в|BLIoGRAPHY

Julian Sorеll Huxlеy Was a Ьiologist, a popular writеr, and a mеmЬеr of Britain's intеlligеntsia.In еvolutionary studiеs,hе promotеd synthеsisduring thе 1930s and 1940s. Hе сontriЬutеd to thе rеvival of sеlесtion thеory with thе puЬliсation of Еuolutioп: Thе Мodeпz Sуnthеsis (1942) and hе сonсеntratеd attеntion onto Сharlеs Darwin аs thе suЬjесt'sthеorеtiсalсеntеr.Huхlеy promotеd еvolutionary taхonoпly, whiсh linkеd сlassifiсation to thе study of spесiation, whilе also sееking oЬjесtivе mеthods for taxononriс work. Huхlеy's сontriЬutions of nеw knowlеdgе wеrе far lеss important than his infесtious еrrthusiasmand еnсourаgеmеnt'as wеll as his аЬiliгy to сorrrЬinе sсattеrеdсonсеpts or idеas into gеnеral prinсiplеs and mеaningful visions. Born in London, Huxlеy attеndеd Еton Collеgе (1900), thеn Balliol Сol. 1еgе,oxford (1906), whеrе hе rесеivеd a first-сlass dеgrее in natural sсiеnсе (zoology). Hе spеnt thе nеxt yеar at thе Naplеs Zoo\oglсa| Station. His first Ьook,Tlэе Iпdiuiduаl iп the Аnimаl Kiпgdom (7912), Was an attеmpt to givе a sсiеntifiсaссount of еvolution inspirеd Ьy thе rесеntly puЬlislrеd Еuolutioп Сreаtiсe by thе Frеnсh philosophеr Неnri Bеrgson (Huхlеy always rеtainеd a fondnеss for thе vitalism of Bеrgson whilе rеalizing that it сould nеvеr Ье truе sсiеnсе).In thе сoursе of thе Ьook, r'rsingas an еxaпlplе thе сompеtition at the tinrе Ьеtwееnthe British and Gеrman naviеs, Huхlеy introduсеd thе idеa of а Ьiologiсal ,.arms raсеs'' Ьеtwееn сompеting lirrеsof organisrns' an idеa

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Hихlеу,.|uliапS. thаt has Ьееn muсh еndorsеd Ьy suсh thinkеrs as Riсhard Dawkins (1986).In 1910, Huxlеy rесеivеd his first taсulty аppointmеnr, irr zoology аrtoxford. Whiiе in Oхford hе undеrtook his first majсrr rеsеarсh suссеss,а study of сourtship rituals and sеxual sеlесtion in thе grеat сrеstеd grеЬе. Hе also dеvеlopеd skill in ехpеrimеntal еmbryology. Huxlеy's сarееr irrсludеd many еmployеrs. In 1,9|2, Ье aссеptеd an offеr from thе Riсе Institutе in Houston to dеvеlop a nеw dеpartmеnt of Ьiology, .sfhеn .W.ar whiсh provеd diffiсult. World I еrupted, hе rеturnеd to Еngland. During thе war, Huxlеy sеrvеd mainly in аrmy intеlligеnсе.In 1919, hе rеturnеd to Oxford's zoology dеpartmеntаnd сonсеntrаtedhis attеntion on dеvеlopmеntal Ьiology and physiologiсal gеnеtiсs.In 1920, hе rеportеd on thе aЬility of hormonеs to provokе mеtamorphosis in axolotls. This rесеivеd сonsidеrablе prеss attеntion and sеrvеd as zrсatаlyst for his lifеlong involvеmеnt in thе nrеdiа. Нuхlеy also invеstigatеdthе rеgulation of ratеs of gеnе еxpression and proЬlеms of rеlativе growth' suсh as allomеtry. In |925,Ье movеd to King's Сollеgе London' aссеpting thе position of profеssor in zoology and laЬoratory dirесtor. Two yеars laсеr,Нuхlеy rеduсеd his position to an honoгary onе and lеft King's to pursuе a сarееr as a frееlanсеwritеr. His сontriЬutions to his sсiеnсе arе summarizеd in Problеms of Relаtiuе Groruth (Huхlеy \932) and The Еlemeпts of ЕхperimепtаI Еmbrуology (Huхlеy and dе Bееr 19з4). Thеsе еarnеd Huxlеy еlесtiorrto thе Royal Soсiеty in 1938. Huхlеy's most important frееlanсеprojесt was a сollaЬoration with Н. G. .sИеlls and G. Р. to survеy Ьiology and thе history of еvolution, titlеd Thе Sсi(1929). епсe of I'ifе During thе 1930s, Huxlеy сontriЬutеd to nеwspapеrs' magazinеs,radio, and film. Не took on book and еditorial proiесts,as wеll as spеakirrgtours (sееfor ехаmplе Нuхlеy |9З4). Sееmir-rgly еvеrythinginvolving puЬliс sсiеnсеin Britain in thе 19З0s inсluded Huхlеy in somе way. Hе is Ьеst known for his rolе on thе BBС radio program ..Thе Brains Trust'' during \forld \й/arIl. Huxlеy's aЬility to aссеss thе mеdia provеd еssеntiаllatеr in his lifе. In 1935, Huxlеy rеturnеd to institutional еmploymеnt, Ьесoming sесrеtаry of thе Zoologiсal Soсiеty of London. This еntailеd marragingthе soсiеty and .Whilе its zoologiсаl gardеns in Rеgеrrt'sPark and \il/hipsnadе. sесrеtary,Нuхlеy kеpt up his puЬliс сontriЬutions. Hе turnеd his rеsеarсh intеrеsrsto systеmatiсs and еvolution. Huхlеy was partiсulаrly intеrеstеdin еvolution lеading to adаptation and to thе formation of nеw spесiеs.Polytypiс spесiеsаnd gеo. graphiсal variеtiеs (suЬspесiеs)wеrе of intеrеst as thеy suggеstеd..еvolution in aсtion,'' a phrasе Huхlеy oftеn rеpеatеd. He сoinеd thе tеrm сline for cЬaraсtеrs that show gradual сhangе ovеr a gеogГaphiсgradiеnt.FIе аlso еnсouragеd геsеarсh into natllral аnd sеxual sеlесtiorr'Dr"rгingthis pегiod, Нuxlеy organizеd Тhe Nеш Sуstemаtiсs (1940) irnd wrotе Еuolutioп: The Мodеrп Sупthеsis (1942). .!Var Thе outЬrеak of world II in Еuropе radiсally сhаngеd Huхlеy's сommitmеnts. Hе wrotе еxtеnsivеlyagainst fasсism and against Nazi raсist Ьiology, аnd hе strеssеd thе importanсе of intеrnationalism and dеmoсraсy (Huхlеy 1941,194З). Aftеr 1939, Huхlеy сampaignеd vigorously for Amеr-

iсan intеrvеntion in Еurсl1 mеmЬеrs of thе Zoolоgiсa soсiеty. Thеy forсеd his гс

Aftеr sеveral сontriЬuti сonstruсtion, in 1'946 Нl Nations Еduсational, Sсiе rolе suitеd Нuxlеy pеrfес l i t i с a l a s p е с t so f t h е d i r е с gavе UNЕSCO an agеndz vision hе had advoсаtеdfс s е l f f o r i t s f u t u r ее v o l u t l о Wе havе to takе rеsponsih

family planning Programs t i е s i n d е v е l o p i n gс о r r n t r sions, еspесiallyrеgarding еmЬеd a vision of progrеs Aftеr lеaving UNЕSСС sсiеntist-сеlеЬrity.Hе wr Lysеnkoism), travеlеd, aгt Progrеss and сultuгal dе сampaigns (Huxlеy 1954 vious work and еnсouгa rеsеarсh again. Нuхlеy di As a sсiеntist, Huxlеy l-

bеhavior,dеvеlopmеnt, howеvеr, Huxlеy normаl foсusеd attеntion on Ьiol,

thеory and еxplanation. and his intеrеsts shiftеd il w o r k Ь а с k t o t h е s p i n еr topiсs Ьесamе lеss impсl gavе сohеrеnсе and mеаl

ply faсt gathеring. Huхlеy's prеfеrеnсе fo tеndеd for nonspесialist ( 1 9 з 6 ) ,a n d i n h i s f i l m P l е х a m p l е st o i l l u s r r a t еg е providеd a сasе for thе mating Ьеhavior' flight, suссееd admiraЬly in pr< mation and thе еХtraсti a supеrЬ еxamplе. This r

stеad, thе Ьook's aссom ordination ot informаt mуriad fornls of sеlесti Britain for a gеnеration

Hихleу' Juliап S. s R i с h a r dD a w k i n s ( 1 9 8 6 ) .I n tmеnt' in zoology at Oxford. rеsеаrсhsuссеss' a study of эat сrеstеdgrеЬе. Hе also dеп 1912, hе aссеptеd an offеr l nеw dеpartmеnt of Ьiology, эtеd, hе rеrurnеd to Еngland. l intеlligеnсе . In 1919, hе rеtсеntratеdhis attеntion on dе. .In 1'920,hе rеportеd on thе ;is in aхolotls. This rесеivеd talyst for his lifеlong involvеrе rеgulation of rates of gеnе lсh as allomеtry. In 1925,he position of profеssor in zoоl. I u x I е yг е d u с е dh i s p o s i t i o n t o гееras a frееlanсеwritеr. His Problеms of Rеlаtiue Groшth tаl Еmbrуology (Huхlеy and thе Royal Soсiеty in 1938. as a сollaЬoration with H. G. :y of еvolution' titlеd Thе Sciy сontributеd to nеwspapеrs' d еditorialprojесts,as wеll as Sееmingly еvеrything involvэd Huхlеy in somе way. Не is ..Thе tm Brains Trust'' during е d i а p r o v е d е s s е n t i а |I а t е г i n эloymеnt, Ьесoming sесrеtаry lеd managingthе soсiеty and .!Иhilе lsnadе. sесrеtary, Нuхl his rеsеarсhintеrеsts to sysintеrеstеdin еvolution lеading .еs.Polytypiс spесiеsand gеoas thеy suggеstеd ..еvolution :oinеdthе term сlinе for сhar'hiс gradiеnt.Hе also еnсourL.During this pеriod, Нuxlеy rote Еuolution: Tbе Мoderп iсally сhangеdHuхlеy's сomand againstNazi raсist Ьiol:nationalism and dеmoсraсy paignеdvigorously for Amеr-

iсan intеrvеntion in Еuropе. With so muсh of his attеntion еlsеwhеrе, somе mеmЬеrsof thе Zoologiсal Soсiеty of London fеlt Huxlеy had aЬandоnеd thе soсiеty.Thеy forсеd his rеsignationtn \942. Aftеr sеvеral сontriЬutions to thе war еffort and to planning postwar rесonstruсtion, in 1946 Huхlеy Ьесamе first diгесtor-gеnеral of thе Unitеd Nations Еduсational, Sсiеntifiс, and Сultural Organisation (UNЕSСO). This rolе suitеd Huxley pеrfесtly, although hе frеquеntly fаilеd to managе thе politiсal aspесts of thе dirесtorship. He stayеd only two yеars in offiсе. Huхlеy gavе UNЕSCO an agеnda basеd on sсiеntifiс humanism, еxtеnding a Ьroad vision he had advoсatеd for many yеars, that humanity сan rеly onlу upon itsеlf for its futurе еvolution (Huхlеy 1948). Our dеstiny is in our own hands; wе hаvе to takе rеsponsiЬility for еnsuring progrеss. Huxlеy сampaignеd for family planning programs' intеrnаtional сonsеrvation of naturе, and univеrsi. tiеs in dеvеloping сountriеs. Hе аlso usеd sсiеnсе to lеvеragе politiсal disсussions, еspесially rеgarding raсе and inequality. If nothing еlsе' Huхlеy triеd tо еmЬеd a vision of progrеss that was basеd on dеliЬеratе human aсtion. Aftеr lеaving UNЕSСO in 1948, Huхlеy livеd as a frееlanсе writеr and sсiеntist-сеlеЬrity. Hе Wrotе еxtеnsivеly (inсluding influеntial work against Lysеnkoism), travеlеd, and сonsultеd for govеrnmеnt and many othеr groups. Progrеss and сцltural dеvеlopmеnt wеrе two main thеmеs of his ongoing сampaigns (Huхlеy 1'954a,1'954ь, 1959, 1964). Whilе hе rеvisеd somе prе. vious work and еnсouragеd many Ьiologists, hе did not undеrtakе original rеsеarсhagain. Huхlеy diеd in 1975, As a sсiеntist,Huхlеy had spесialistехpеrtisеin sеvеralsuЬjесts,еspесially bеhavior, dеvеlopmеnt, аnd еvolutionary Ьiology. Throughout his сarееr, howеvеr, Huxlеy normally prеsеntеdhimsеlf as a ..gеnегal''Ьiologist. This foсusеd attеntion on Ьiologiсal proсеssеs and prinсiplеs, and gavе priority to .Whilе thеory and ехplanation. his сarееr shiftеd from onе plaсе to anothеr and his intеrеsts shiftеd from spесialty to spесialty, Huxley always linkеd his work baсk to thе spinе of ..gеnеral'' Ьiology. Thе partiсulars of individuаl topiсs Ьесamе lеss important; thе undеrlying gеnеral prinсiplеs wеrе whаt gavе сohеrеnсеand mеaning to partiсulаrs. Without thеm, Ьiology was simply faсt gathering. Нuxlеy's prеfеrеnсе for genеral prinсiplеs is Ьеst illцstratеd in work hе intеndеd for nonspесialistaudiеnсеs.In Ьooks |lke Aпts (1930) or Аt the Zoo (1'9з6),and in his film Priuаte Lifе of tbe Gапnеts (t9З4), hе usеd partiсular ехamplеs to illustratе gеnеral Ьiologiсal phеnomеna. Gannеts, for instanсе, providеd a сasе for thе study of dеvеlopmеnt' parеntal сarе' adaptations, mating Ьеhavior, flight, есology, and so on. This approaсh hеlpеd Huxlеy suссееd admiraЬly in projeсts rеquiring thе еnсyсlopеdiс сollесtion of information and thе еxtraсtion of kеy thеmеs. Еuolиtioп: Тhe Мoderп Sупthesis is a supеrЬ ехamplе. This rеportеd no original rеsеarсhof Huхlеy's making. Instеad, thе Ьook's aссomplishmеnt-and a landmark onе-was Huxlеy's сoordination of information into an ovегall vision aЬout еvolution and thе myriad forms of sеlесtion in nаturе. It hеlpеd shapе еvolutionary studiеs in Britain for a gеnеration.

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Huхleу' lиliап S. I n h i s p o l i t i с s , H u x l е y w a s a p г o g r е s s i v еa n d а h u m a r r i s t( H u x l е y 1 9 2 7 \ . Не Ьеliеvеd hunranity was rеsPonsiЬlе for shaping its own futurе, аnd hе turnеd to sсienсе and rational planning to solvе soсial proЬlеms. Thе Tеn. nеssее Vallеy Authority's еlесtrifiсation projесt, modеrnist arсhitесturе' and urЬan planning wеrе among his favoritе еxamplеs. Hе fеrvеntly supportеd Population and Есonomiс Planning' a soсial poliсy group. Huxlеy w a s n o t a е u g е n i с i s ti n i t s с о m m o n m e a n i n g ( i . е . ' a с t i v е l y r е m o v i n g u n d е s i r a Ь l е s ) ,b u t h е s u p p o r t е d p o s i t i v е i n с е n t i v е st o i m p r o v е d е s i r a b l е q u a l i tiеs as wеll as birth сontrol for population managеmеnt. At thе samе timе, hе loЬЬiеd for improvеmеnts to puЬliс hеalth and poor living сonditions. Huxlеy arguеd strongly against thе usе of rасе as a sсiеntifiс or politiсal сonсеpt and Ьittеrly opposеd fursсism.Не supportеd Ьoоsting aid to dеvеloping сountriеs' еspесially aid toward improving infrastruсturе) еduсation' and agriсulturе. l\4r'rсhof his agеnda in UNЕSCO supportеd thеsе aims. |п 1919, Huхlеy marriеd Mariе Juliеttе Baillot (|895_7994). Thеy had two sons. Likе his grandfathеr Thomаs Hеnry Huхlеy' Julian Нuхlеy's lifе was punсtuatеd Ьy pеriods of sеvеrеmarriс dеpгеssion,whiсh somеtimеsdеЬilitаtеd him or lеd to major transitions in his lifе (suсh аs lеaving aсаdеmia). Не wrotе dеtailеd and informativе mеmoirs and is now thе suЬjесt of inсrеasing intеrеst Ьес:rusеof thе widе sсopе of his thinking (lй/atеrsand van Hеldеn 1992; Rusе 1996), вlвLloGRAPнY Dawkins'R. 1986.Thе Blind Wаtсhmаkеr. Nеw York: Norton. Huхlеy, J' S. 1912.,Thе lпdiuiduаl iп thе Апimаl Kiпgdom, СamЬridgе:СamЬridgе UnivеrsityPrеss. 1927. Rеligiсlпtt,ithoutRеuеlаtiсlп.London: ЕrnеstBеnn. 19ЗО.Aпts. London:JonаthanСapе. |93I. Wbаt Dаre l Тhiпk! Тhе СhаIlеngеL'lfМсldеrпSсieпceto Htlпlс1п Асtiсlпапd Bеliеf. Nеw York: Harpеr and Brothеrs. \932, Problemsсlf RеlаtiuеGrсlluth.London: Меtlruеn. 1934. lf I WerеDiсtаtor. Nеw York: Hаrpеr аnd Brothеrs. 19з6.Аt thе Zсto.London:Allеn and Unwin. 1940. The Nеu.,S1'51n*ofiсs. Oхford: СlarеndonPrеss. |941. Мап StaпdsАloпе.Nеw York: Наrpеr. .Гhe 7942.Еuolнtion: Мodеrп Sу'пthesis. London: Allеn and Unwin. 1943. TVА: Аduenturеiп Plаппiпg,London: SсiеntifiсBоok СluЬ. 1948. UNЕsСo: ItsPurposеапd ItsPhilosrlphу. DС: PuЬliс Washington, Affairs Prеss. 1'954a.Тhе еvolutionary proсеss.In J. Huхlеy,A. С. Hаrdy, and Е. B. Ford, eds.,Еuolutioп аs d Prсlсеss'1_23.L
Huхlе,v, J. S., and G. dе Bе С а m Ь r i d g е :С a l п Ь r i d g Rusе, М. 1996. Мoпаd tсl СamЬridgе' MA: Нarl .Watеrs, С. K., and A. vаn l of Sсiепсе. Нoustсln: F !7еlls, H. G.' J. s' Нuхlеy, Amаlgirmаtеd Рrеss.

Huхlеy, Thomas H

Thomаs Hеnry Нuхlеy ogy еduсatoг' and popt Bulldog,'' сonсеals morс sсiеntifiс profеssion and rival pulpits. Trainеd as a surЕ] (1841'-1842), and at С o n I I М S R а t t l е s п а k еt 1846_1850. His papеr m а l l - o t - W a r )w , hiсh сstа tion mеmЬranеs (есtod Royal Меdal in 1852. Thе joЬlеsstyro dеnot tbe Nаturаl Historу'of С, life upward. Сharlеs Da: Down Housе in 1856 t< сonvеrtеd. Now thе lесt H u х I е y i m m е d i а t е l ус a r pushеd farthеr thаn Dаг from apеs taхonomiсall1 g o r i l l a a n a t o m y .L е с t u r humаns had animal anсе fumеd thе еvangеliсal \, wаs playing to nеw audi tion wеrе familiаr in strс image of noЬlе-futuге.fr gliсan aristoсraсy, Ьut th Thе puЬliсation of Dl nеw sсiеnсе profеssio mаnkind .rndwhlt Ьes dеploуеd whаt hе сallеd ism.'' His Maniсhеan pt today hе is rесallеd for Assoсiation for thе Ad' had plaуеd on Viсtorii inquiring whеtlrегthе a

Huхlеу, Tbсlmаs Hепrу a humanist (Huxlеy 1'927). ping its own futurе' and hе е soсial proЬlеms. Thе Tеn. сt, modеrnist arсhitесturе, :хamplеs.Hе fеrvеntly sup;oсial poliсy group. Huxlеy .е., aсtivеly rеmoving undеto improvе dеsiraЬlе quali. managеmеnt. At thе samе е a l t ha n d p o o r l i v i n g с o n d i _ of raсе аs a sсiеntifiс oг po'е suppоrtеd Ьoosting aid to proving infrastruсturе, еdui UNЕSСO supportеd thesе l l o t ( 1 8 9 5 _ 1 9 9 4 ) .T h е y h a d Huхlеy, Julian Huxlеy's lifе геssion,whiсh somеtimеs dе:е(suсhas lеaving aсadеmia). nd is now thе suЬjесt of inris thinking (.!flatеrsand van

:k: Nortor-r. rgdom. СanlЬridgе: СamЬгidgе Еrnеst Bеnn. ( Мodеrп Sс'ienсеto I{unlаlt tеrs. -r:Mеthuеn' : аnd Brothеrs. l.

'don Prеss. r. ndon: Allеn and Unwin. : Sсiеntifiс Book СluЬ. ;pЙy. \й/ashington,DС: Publiс еv, A. С. Нardy, and Е. B. Ford, эn and Unwin. human dеstiny.UnpuЬlishеd ).9, Huxlеy Papеrs, Riсе tn,Thе Phutotпепoп of Мап, o andWindus. 1n.

Huхlеy' J. S.' and G' dе Bееr.1934',ГheЕlemепtsсlf ЕхpеrimепtаlЕmbrуologу. СamЬridgе:CаmЬridgеUnivеrsityPrеss. Rusе,М. 1996.Мoпаd to Мап: The Сoпсеptсlf Progrеssiп ЕuolutiottаrуBioklgу. Сambridgе,\4A: Harvard UnivеrsityPrеss. Watеrs,С. K., and A. vаn Неldеn,еds. l992. lиliап Нuхlе1,:Biсlklqistапt! Stаtesmап of Sсiепсе'Houston:Riсе UnivеrsityPrеss. Wеlls,H. G.' J. s. Huхlеy,and G. P. Wеlls.1929.Тhе Sсiепсеof Lifе. London: Amalgamatеd Prеss.

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Huxlеy,Thomas Hеnry (1825-1895) Thomas Hеnry Huхlеy was an invеrtеЬratеanatomist' pаlеontologist, Ьiology еduсator, and popularizеr of еvolution. Huxlеy's niсknamе, ..Darwin's Bulldog,'' сonсеals morе than it rеvеals:hе wаs a puЬliсist for thе еmеrging sсiеntifiсprofеssion and usеd Darwinism's naturalistiс idеology to undеrсut гival pulpits. Trainеd as a surgеon at an anatomy sсhool, Sydеnham Сollеgе (184\_1842), and at Charing Сross Hospita| (1842-1845), Нuхlеy sailеd on НMS Rаttlesпtthe to Australia's Grеat Barriеr Rееf during thе yеars 1846-1850. His pirpеrs on thе siphonophorеs (similar to thе Portuguеsе nran-of-war),whiсh еstaЬlishеdtlrat all сoеlеntеratеsсomprisеd two foundation memЬranеs (есtodеrm and еndodеrm), won him thе Royal Soсiety's Royal Меdal in 1852. Thе joЬlеss tyro dеnounсеd Robеrt СhamЬегs's transmutatioг.ist Vеstigesof the Nаtцrаl Histсlrу of Сrеаtiсlп (1854) for its mаnnikin-likе divinе laws pulling lifе upward. Сharlеs Darwin's natuгаlism, howеvеr' was appеirling. Сallеd to Down Housе in i856 to air his oЬjесtions to еvolution, Huхlеy саmе away сonvеrtеd. Now thе lесturеr in natural history ar London's Sсhool of Мinеs, Huхlеy immеdiatеlу сariсaturеd sllpеrnatural ..Сrеation'' in сlass. Publiсly hе pushеd farthеr than Dzrrwin:whеге Riсhard owеn in 1857 distаnсеdhumans from apеs taхonomiсally' Huхlеy in 1858 dгеw parallеls Ьеtwееn humаn and gorilla anatomy. Lесturing to working mеn in 1859, Huxlеy said outright that humans had animаl anсеstors-thе ..vilеstand Ьеastliеstparadox еvеr vеntеd;'' fumеd thе еvangеliсalr'Witпesson hеaring Huхlеy in Еdinbuгgh. But Huхlеy wаs playing to nеw audiеnсеs;pгiеstсraft-pгiсkingassеrtionsof human еvolution wеrе familiar in strееt prints. A sеlf-profеssеd..plеЬеian,''lrе сonjurеd an imagе of noЬlе-futurе-from-lowЬorn-Ьеginningsthat mеant nothing to thе Angliсan aristoсraсy' but thе frееthinking mесhaniсs lаppеd it up. Thе puЬliсation of Darwin's Оп the Оrigiп сli Spесies (1859) еrraЬlеdthе .Whеnсе nеw sсiеnсе profеssionаl to usurp old thеologiсal quеstions: marrkind and what Ьasis morality? Against thе сonsеrvativесlеrgy, Huxlеy dеployеd whаt hе сallеd Darwin's ..Whitworth gun in thе armoury of liЬеral. ism.'' His Мaniсhеan portrayal of sсiеnсеvеrsus thеology madе nеws. Еvеn todаy hе is rесallеd for upЬraiding Bishоp Samuеl \й/ilЬеrfoгсеаt thе British .WilЬеrforсе Assoсiation foг thе Advanсеmеnt of Sсiеnсе mееting in l860. had playеd on Viсtorian sеnsibilitiеsaЬout thе sanсtity of womanhood Ьy inquiring whеthеr thе apеs wеrе on Huхlеy,s grandfathеr's or grandmothеr's

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Hихleу, Tbсlmаs Неnrу sidе. In рrеfеrring an apе anсеstor ovеr a Ьishop who prostitutеd his talеnts' Huxlеy, thе Puritаn, oozеd moral soЬriеty to shamе thе worldly NИilЬеrforсе. Suсh сonfrontations only еxaсеrЬatеd thе Viсtorians' ..сrisis of faith.'' In 1861, Нuxlеy deniеd owеn's сlaim that apеs laсk thе human's third сеrеЬral loЬе' whosе сavity has a postеrior horn with a projесting ..hippoсampus minor.'' Сhаrlеs Kingslеy tnThе'Wаter Bаbiеs laughеd aЬout ..hippopotamus majors,'' and thе affray Ьrought human еvolution squarеly to thе puЬliс's attеntion. Huxlеy madе his nеwly aсquired Nаturаl Historу Rеuieta an anti. Owеn organ and sеt thе trеnd with his artiсlе ..On thе Zoo\ogtca| Rеlations of Мan with the Lowеr Animals'' (1861). Huхlеy's wоrking-сlass talks, сouplеd with a lесturе on fossil humans (foсusing on thе rесеntly unеarthеd Nеandеrthal Man). formеd thе сornеrstonе of his Еuideпce аs to Мап's Plаcе iп Nаture (1863). Нuxlеy studiеd Dеvonian fishеswith loЬе fins and similar-looking amphiЬ. ians, сallеd lаЬyrinthodonts, from thе strata surrounding сoal sеams.Rathеr than draw еvolutionary сonnесtions' hе еmphasizеd that laЬyrinthodonts had pеrsistеd unaltеrеd for immеnsе pеriods. Initially, Huхlеy Ьеliеvеd that thе major groups had еvolvеd Ьеforе Silurian timеs and had сhangеd littlе sinсе. Only whеn Darwin's Gеrman supportеr' Еrnst Haесkеl, puЬlishеd on phylogеny' or raсial anсеstry' did Huхlеy rесonsidеr. In 1'867,Huхlеy rесlassifiеd birds gеnealogiсally,and in 1868' hе famously suggеstеdthat thе small dinosaur Сompsogпаtbus сoti.d havе Ьееn anсеstral to Ьirds (and may havе Ьornе fеathеrs). Hе dramatizеd thеsе rеlationships and promotеd o. С. Marsh's horsе fossils from NеЬraskа on his Amеriсan tour of 1876. onе illustration in Amеriсап Аddressеs (1877), showing thе inсrеasing lеg and tееth sizе from thе small thrее-toеd Еoсеnе Оrohippиs to thе tiptoеing Еquus, was сitеd as thе dеfinitivе fossil еvidеnсе of еvolution for gеnеrations. Latеr hе dеsсriЬеd thе еvolution of thе sесondary palatе in сroсodilеs. .!Иhеrе Huxlеy's attitudе toward Darwin's mесhanism rеmainеd еquivoсal. Darwin еnvisagеd variation oссurring in minusсulе stеps, Huхlеy in 1859 piсturеd an innеr forсе produсing nеw spесiеs at onсе. His еntry on ..Еvolution'' in the Епcуclopаediа Britаппicа (1878) mootеd natural sеlесtion only onсе' and Huxlеy's асadеmiс work Ьypassеd it сomplеtеly. Нuxlеy rеsеrvеd his disсussion for popular talks: hеrе natural sеlесtion was likеnеd to Napolеon's troops rеtreating from Mosсow and сrossing the Bеrеsina Rivеr, ..еvеryonе hееding only himsеlf,'' thе fittеst alonе rеaсhing thе far Ьank. Мostly, Darwin's Мalthusian mесhaniсs sеrvеd Нuxlеy in сomЬating soсialism or dеЬunking сrеationism.Also, hе avoidеd еvolution in сlass Ьесausеhе Was training sсiеnсеsсhoolmastеrsaftеr thе Еduсation Aсt (1870). ЕstaЬlishing his first propеr laЬoratory in South Kеnsington in1'871', hе fashionеd a praсtiсal ..biology'' Ьasеd on thе сommon plant and animal ..Typеs.''This in. fluеnсеd sсhool сurriсula until thе mid-twеntiеth сеntury. But inсulсating a disсrеtе ..Typе'' systеm lеft littlе room for еvolutionary disсussions. opеning Birmingham's nеw Sсiеnсе Сollеgе, Huxlеy сontrаstеd thе rесyсling of thе сlassiсs at thе Angliсan univеrsitiеs with sсiеnсе's ехpеrimеntal approaсh. Thе undеrvaluеd sсiеntifiс rеsеarсhеr' hе сontеndеd, would Ье Ьеttеr quali-

fiеd to lеad industrial so him. As Dissеntеrs (out taking Oхford and Сar tion'' lеgitimizing thеir g Huхlеy madе thе wor. a naturalistiс mеaning, . spirituаlist A1frеd Russеl Huхlеy сoinеd thе word to Ье ..agnostiс'' aЬout with сlean hands to Ье tr aS thе nеutral profеssion his lаst yеars аrguing h shaping a сеntury of еvo Although еvolution w form, Darwinism's wеal lесtion had raisеd manki ..Еvolution and Еthiсs'' ( ..moral indiffеrеnсе.'' Еt turе within naturе'' som Ultimatеly, thе suprе whаt сonсеrnеd Нuхlеy z еrеd. Whеrеas his Sсieиt tivе' his ninе volumеs o] showing the Viсtorian a1 H. L. Меnсkеn сallеd H who has еvеr livеd.'' BIвLIoGRAPHY

Barr, A. Р., ed. 1997.Тhoп СeпteпаrуЕssays.Ath Dеsmond,^. 1997.Нuхlе Rеading,МA: Addiso Di Grеgorio,М' 1984.Т. I Y а | еU n i v е r s i tPy r е s s Lyons, S. L. 1999. Тhomаs NY: PromеthеusBооk Paradis,J. G., and G. с' !( PrinсеtonUnivеrsityP Y/hitе,P. 2003. ThсlmаsHl СambridgеUnivеrsity

Htlхlеу, Thomаs Hепrу эp who prostitutеd his talents, .!ИilЬеrforсе. hamе thе worldly ..сrisis of faith.'' In /iсtoriаns' aсk thе human's third сеrеЬral ..hippoсampus h a pгojесting ..lrippopotamus laughеdaЬout ion squarеlyto thе puЬliс's atIurаl Historу Rеuiеtu an аnri..on the Zoologiсal Rеlations
fiеd to lеаd industrial soсiеty.This dеlightеdthе stееl magnatеswho finаnсеd him. As Dissеntеrs (outsidе thе Angliсan Сhuгсh), thеy wеrе ехсludеd from taking Oxford аnd СamЬгidgе dеgгeеs and saw Huxley's ..nеw Rеformation'' lеgitimizing thеir growing сiviс authority. Huxlеy madе thе word euolиtloz fashionaЬlеaround 1870. Foг him it had a natllrаlistiс mеаning, wlrеrеas for thе Сatholiс St. Gеorgе Мivart аnd thе .sИаllaсе spiritualist Alfrеd Russеl it сonvеyеd thе fiat of a highеr powеr. Неnсе, Huхlеy сoinеd thе word аgпosis in 1869. Biologists, as сultural lеadеrs, had to Ье..agnostiс'' aЬout supеrnatuгal issuеs. They had to appгoaсh sсiеnсе with сlеan hands to Ье trustеd.Huxlеy hеlpеd mold thе imagе of thе sсiеntist as thе nеutral profеssional,аnd of еvolution as dеmystifiеdsсiеnсе.Hе spеnt his last yеars arguing his antimiraсulous сasе in thеologiсal сontrovегsiеs, shaping a сеntury of еvolution-сrеationdеЬatе. Althсlugh еvolution was finе for dеmolishing Angliсan doors сlosed to rеform, Dаrwinism's wеak-to.tlrе-wall r"rpshotpеrturbеd Huxlеy. A Ьrural sе. lесtion had raisеd mankind, Ьut it сould not ехplain our сarе of thе wеаk. In ..Еvolution and Еthiсs', (189з) hе portrayеd еthiсal man rеnounсing naturе's ..moral indiffеrеnсе.'' Еthiсs wеrе fort-nеdЬy еvolution' yеt mankinсl's ..naturе within natuге'' somеhorvworkеd аgainst thе primitivе sеlесtivеforсеs. Ultin-latеly, thе suprеmaсy of sсiеnсе' naturаlism' and agnostiсism wеrе what сonсеrnеd Huхlеy as a populist. This wаs еvidеnt as his works wеrе gath. еrеd. Whеrеas his Sсieпtфс Меmoirs (fivе volumеs, 7898_|902) wеrе dеsсriptivе, his ninе volumеs of еssays (789З-7894) wеrе sсintillating prosе works showing thе Viсtorian agе aссommodаting itsеlf to еvolution. Rеading thеm, H. L. Меnсkеn саllеd Huxlеy ..pеrhaps thе grеatеst virtuoso of plain Еnglish who has еvеr livеd.'' BIBLIOGRAPHY Barr, A. P., еd' 1997. Тhr.lmаsI7епrуНuхlеl',sPlасе irt Sciепсеапd Lеttеrs: СепtenаrуЕssаys.Athеns:Univеrsit,vof Gеorgia Prеss. Dеsmond,^. 1997. Huхleу: From Deuil's Disсiplе tсl Еuolutioп'sHigЬ Priеst' Rеading,МA: Addison.IWеslеy. Di Grеgorio'N4.1984. T. H, Huхlеу's Plасе iп Nаturаl Sсiепсe.Nе'"vНаvеn' СT: Y а l еU n i v е r s i tPr 'r е s s . Lyons' S. L. |999. I'homаsHепrу Hихlеу: Тhe Еuolutiсlпof а Sсiепtisf.Amhегst, NY: PromеthеusBooks. Paradis,J. G.' and G. С. Williапrs,еds.19ti9.Еuolutiсlпапd Еthi<:s. Prinсеtоrr, NJ: PrinсеtonUnivеrsityPrеss. Whitе,P. 20ОЗ.Tbomаs Huхlеу: Маkiпg the ,,Мап of Sсiеnсе'''СamЬridgе: -A.D. CambridgеUnivеrsityPrеss.

б)/

Industrial mеlanism Industrial mеlanism rеfеrs tо thе еvolution of dark Ьody сolors in animal spесiеs that livе in haЬitats blaсkеnеd Ьy industrial soot. Of аpproximatеly 1 0 0 r е p o r t е dе х a m p l е s 'm o s t a r е i n s е с гs p е с i е s .a n d o f t h е s еt h e v a s t m а j o r ity arе moths' Thе most thoroughly doсumеntеd ехamplе is thе pеppеrеd mot|t, B i ston b etиlаr iа. Thе сommon name dеsсriЬеsthе appеaranсе(or phеnotypе) of thе typiсal adult, a palе moth ..pеppеrеd'' with Ьlaсk-and-whitе sсalеs (sее figurе). Mеlaniс phеnotypеs' namеd сarЬonaria, arе еssеntiallysolid blaсk. Intеrmеdiatеs, or insularia, also oссur Ьut rесеivе rеlativеly littlе attеntion in gеnеral summariеs. Еxtеnsivе gеnetiс analysis сonfirms that thе phenotypеs arе dеtеrminеd Ьy multiplе allеlеs at a singlе gеnе loсus. Thе mеlaniс phеnotypе Was first disсovеrеd nеar Мanсhеstеr, Еngland, in 1848. By 1895' about 98'Ь of thе spесimеnsnеar Мanсhеstеr wеrе mеlaniс; this onсе rarе phеnotypе had sprеad aсross thе industrial rеgions of Grеat Britain. With only onе gеnеration pеr уеar' thе nеarly сomplеtе rеvеrsal in .!7еll phеnotypе frеquеnсy was astonishingly rapid. away from industrial rеgions, mеlaniс spесimеns rеmаinеd rarе. British lеpidoptеrist J. \Х/.Tutt advanсеd thе following Darwinian еxplanation in 1896: Pеppеrеd moths arе aсtivе at night and rеst during daylight hours' hiding on thе surfaсеs of trееs. Мost insесtivorous Ьirds hunt Ьy day and loсatе prеy primarily Ьy vision. Мoths that arе wеll сonсеalеd against Ьaсkgrounds upon whiсh thеy stay motionlеss arе morе likеly to еsсapе dе. tесtion Ьy Ьirds than arе сonspiсuous moths. Tutt proposеd that typiсal pеppеrеd moths in undisturЬеd environmеnts gain protесtion from visual prеdators Ьy thеir rеsеmЬlanсеto liсhеns on trее Ьark. In manufaсturing rеgions whеrе liсhеns havе Ьееn dеstroyеd Ьy pollution and thе surfaсеs of trееs havе Ьееn Ьlaсkеnеd Ьy soot, thе typiсаl phеnotypеs losе thеir сamouflagе and fall viсtim to Ьird prеdators' whеrеas thе mеlaniс phеnotypеs in suсh pollutеd habitats еsсapеdеtесtion long еnough to pass thеir gеnеson to progеny. Tutt's idеas wеrе not tеstеd until thе 1950s whеn Bеrnard Kеttlеwеll (197З) initiatеd a sеriеsof еxpеrimеntsto dеtеrminеwhеthеr or not Ьirds aсtually atе mеlaniс and typiсal pеppеrеd moths sеlесtivеly. His еxpеrimеnts inсludеd thrее main сomponеnts: (1) quantitativе rankings of сonspiсuousnеss (to thе human еyе) of typiсal and mеlaniс phеnotypеsplaсеd on various 6.t2

Palе and dark (mеlаniс)f

Ьaсkgrounds; (2) dirесt onto trее trunks; and (3 in pollutеd and unpollr tlеwеll's pionееring ехpt thе yеаrs. Сritiсisms aЬс usеd' thе positions on tr moths wеrе rеlеasеd,an< inspirеd ninе additiona was a sеvеn-yеar study I N4ajеrusrеlеasеdliving thеir own 'hiding plaсеs propoгtions to matсh lо Ьinoсulars hе madе dirс pеppеrеd moths. By сol usеd in thеsе prеdatiоn virtually matсhеd thе sе t h е m е l a n i с p h е n o t у p еi Thе wеight of еvidеnсе l pеrеd moth phеnotypеs Ьy еxpеrimеnt. Bесausе thе rеflесtarк nеgativеly сorrеlatеd w tеstaЬlе prеdiсtion is th s o o t y ' p o I I u t е dr е g i o n s wаs сlеаrly mеt Ьy thе

]ndustriаl Мelаnism

of dark Ьody сolors in animal lustrial soot. of approхimatеly е s , а n d o f t h е s еt h е v a s t m a j o г еntеd ехamplе is thе pеppеrеd се (or phenotypе) of thе typiсal :-and-whitеsсalеs (sее figurе). еssеntiаllysolid blaсk. Intегmеrtivеly liшlе attеntion in gеnеral ms that thе phenotypеs arе dеcсus. d nеar Мanсhеstеr' Еngland, in nеar Manсhеstеr wеrе mеlaniс; thе industrial rеgions of Grеat thе nеarly сomplеtе rеvеrsal in l. \7еll away from industrial rее following Darwinian еxplananight and rеst during daylight insесtivorous Ьirds hunt by day that arе wеll сonсеаlеd against ss arе morе likеly to еsсapе dеTutt proposеd that typiсal pеp; gain protесtion from visual t r е еЬ a г k . I n m a n u f a с t u г i n gr е r pollution and thе surfaсеs of rl phеnotypеslosе thеir сamour е a sr h е m е l а n i с p h е n o t y p е s i n эnoughto pass thеir gеnеs on to 950s whеn Bеrnard Kеttlewеll еrmitrеwhеthеr or not Ьirds aсг h s s е l е с t i v е I yH. i s е x р е r i m с n t s t a t i v ег a n k i n g so f с o n s p i с u o ц s s lасеdоn various i с p h е n o r y p еp

Palеand dаrk (mеlаniс)foгms of thе pеppеrеdmоtlr,Вistoп bеtulаriа.

(2) dirесt obsеrvationsоf prеdation Ьy Ьirds on moths plaсеd Ьaсkgror.rnds; onto trее trunks; and (3) гесapturеratеs of markеd moths rеlеasеdonto trееs in pollutеd and unpollutеd woodlands. Thе dеsign and еxесution of Kеttlеwеll'spionееring еxpеrimеntshavе Ьееn suЬjесtеdto intеnsе sсrutiny ovеr thе yеars. Сritiсisms about his mеthods (inсluding thе dеnsitiеsof thе moths usеd' thе positions on trеes whеrе thе moths wеге plaсеd, thе timе of day thе moths wеrе rеlеasеd,and thе usе of laboratory-rеarеdand wild-сaught moths) inspirеd ninе additional ехpеrimеnts Ьy othеr rеsеarсhеrs.Thе most rесеnt Was a Sеvеn-yеarstudy Ьy Мiсhaеi Мajеrus, сomplеtеd in 2007. Spесifiсally, Majеrus rеlеasеd living moths into arеnas at dusk so thеy сould dеtеrminе thеir owrr hiding plaсеs on trееs Ьеforе dawn. Hе adjustсd thе phеnotypiс proportions to matсh loсаl frеquеnсiеsаnd kеpt thе dеr-rsitiеs low. Through Ьinoсulars he madе dirесt oЬsеrvatior-rsof ninе diffеrеnt Ьird spесiеs еating pеppеrеd moths. By сomparing thе survival ratеs of thе moth phеnotypеs usеd in thеsе prеdation ехpегimеnts'Ьe сalсulatеd sеlесtionсoеffiсiеntsthat viгtually matсhеd thе sеlесtion сoеffiсiеnts dеrivеd from thе rаtе of dесlinе of thе mеlaniс phеnotypе in thе loсal population ovеr thе сoшrsеof his study. Thе wеight of еvidеnсеnow supporting Tutt's hypothеsis сhat Ьirds еat pеppеrеd nroth phеnotypеssеlесtivеlyis suЬstantialand rеmains unсontгadiсtеd Ьy ехpеrimеnt. Bесausе thе rеflесtanсе of light fronr thе surfaсе of trее bark is strongly nеgativеly сorгеlаtеd with аtmosphеriс lеvеls of suspеndеd partiсlеs, thе tеstaЬlеprеdiсtion is that rnеlaniс phеnotypеs should Ье morе сommon in sooty' pollutеd rеgions than thеy arе irr unpollurеd rеgions. This prеdiсtion was сlеirrly mеt by thе frеquеr-rсyсlf nrelaniс pеppеrеd moths distriЬutеd

65З

6.'4

Industriаl Меlапisпt among 30,000 spесiпrеnsfrom populations survеyеd at 83 loсations aсгоss Britain Ьеtwееn 1952 and 1970. Тhе gеographiс distriЬution of mеlanism in pеppеrеd moths is morе strongly сoгrеlatеd with atmosphеriс lеvеls of sulfur dioxidе (So,) than with smokе. SO,, as а gas, is morе widеly dispеrsеdfrorn point sourсеs than pirrtiсulatе mattеr that tеnds to sеttlеloсallу as soot. Although sеlесtitlnmaу opеratе loсally' gеnе flow from thе migration of individuals among populations has сontriЬr.rtеd to morе gradual сlinеs in mеlanism in pеppеrеdmoths, a rеlativеly moЬilе spесiеs,than in morе sеdеntarymoth speсiеs(е'g., Goпodoпtis [=gtron'optеrаl bidепtаtа) in whiсh frеquеnсy distriЬutions of mеlaniс phеnotypеsarе morе sharply suЬdividеd ovеr thеir rаngеs.The powеr of gеrrе flow tо oЬsсurе gеnеtiс аdaptation to loс:rl сonditions rеsulting from sеlесtion was littlе apprесiаtеd Ьy еarly rеsеaгсhеrs,lvho еntеrtainеd various forms of nonvisual sеleсtionin attеmptsto aссount for appaгеntanоmaliеs in сlinеs. Мolесular tесhniquеs using nonсoding DNA sеqrrеnсеshаvе now Ьееn dеvеiopеd for pеppеrеd nroths Ьy Ilik Saссhеri and his assoсiatеs(Daly et aL.2004)' Thеir analysis of 12 miсrosatеllitеloсi from populations aсross a 125-kilomеtеr transесt from north.s7'alеsto Lееds, Еngland, indiсatеs high lеvеls of dispеrsal and gеnе florд,.This and futшrеwоrk should hеlp qr'rantify thе rolе of migration in thе еvolution of mеlanism in this spесiеs. In 1956 Rritаin initiatеd thе Сlеan Air Aсts to еstaЬlishso-сallеdsmokеlеss zonеs in hеavily pollutеd rеgions. Following signifiсant rеduсtitltrsin etmosphеriс pollution' mеlaniс pеppеrеd moths Ьavе dесlinеd in fгеquеnсy as thе typiсal form rесovеrеd.Indееd, thе dесlinе in mеlanism in thе iattеr half of thе twentiеth сеntury is far Ьеttеr doсumеrrгеdthan rhе inсrеasеin mеlanism in thе lattеr half of thе ninеtееnthсеntury. An unintеrruptеd аnnual rесord 18 kilomеtеrs wеst of Livеrpool Ьеgun in 1959 Ьy Сyril Сlarkе (Сlarkе еt al. 1985) inсludеs nеarly 19,000 spесimеnsshowing a drop in thе frеquеnсy of mеlaniсs fгonr a high of 9З"Ь to Ьеlow.5ol, Ьy 2003 (Grzrnt2005). The most rесеnt national survеy' takеn in 1996 (Grant еt al. l998) shorvs markеd dесlinеs in mеlanism havе oссurrеd еvеrywhеrе in Britain. Thе prеdiсtеd сorrеlzrtionЬеtwееn сhangеs in thе lеvеls of pollution аrrd in thе frеquеnсiеsof п-rеlaniсphеnotypеs in pеppеrеd motlr populations Ьas Ьееn fiгmly еstaЬlishеd. Bruсе Gr:rnt and Dеnis Owеn (Grant еt al. 1996) have doсuп.rеntеdparallеl еvоlutionary сhangеs in Ьoth dirесtiсlnsirr thе Nortlr Amегiсan pеppеrеd motь, Biston betulаriа сogпаtаriа. Mеlaniс phеnotypеs in thе suЬspесiеs rеsult from allеlеs at thе samе gеnе loсus (Grаnt 2004|' Ьut thе risе and sprеad of mеlanism in Amеriсаn populi.rtionsstartеd aЬout 50 yеаrs lаtеr thаn irr Britain. Еarly musеum сollесtions do not inсludе any mеlаrniсspесimеns prior to 7929 in thе viсinity of Dеtroit, Miсhigаn, Ьut Ьy 1959 thе frеquеnсy of mеlaniсs had rеaсhеd 90%. Сlеan аir lеgislаtion Was thеn inzruguratеdin thе Unitеd Statеs in 1963. Rесords ior sotrthеastеrllМiсhigirn shtlw tlrаt at_ mosphеriс SO, and suspеndеd partiсlеs suЬsеquеntlydесlinеd signifiсantly. Bу 1994 thе frеquеnсy of mеlaniс pеppеrеd moths hаd fallеn to 20oЬ, dropping to 5"А Ьу 2001 (Grant and Wisеmаn 2002). Thе signifiсаnсеof a sh:lrp

dесlinе in mеlanism in in atmosphеriс pollutiс tions from southwеstе thе samе timе intеrval tions of So, thаn thе mеnts wеrе takеn at Ьс Amеriсan and Britis monomorPhism for th, dцсеd lеvеls of аtmosl сorrеlations alonе do n suggеStсommon сausе Еvolution ls dеfinеd.

quеnсy in а populatiоn to obsеrvе еvеtr now) tl сisеly. of thе four priп flow, аnd sеlесtion-ol .Whеthе tionirl сhangеs. is thе solе, proximal aд tion in thе еvolr-rtionоf . сurrеd in populations. eхpеrimеnts aimеd at i ouflagе from prеdators ln all аrеas of асtiv гions and intеrprеrаt portanсе of gеnе flow, thе bеhavior and есolt an outstanding ехamp sеt on rесord dосumс populations.

B|вLIoGRAPHY

C l а г k е ,С . А . , G . S . М a n thе pеppегеdmоrh. С o o k , L . М . 2 0 0 3 . T h еr Quаrtеrlу Rеuiеluo1 Dаly, D., K' !Иaltham, J. S a с с h е r ]i .0 0 4 .Т г i n bеtu!аriа)'МolесиIа Grаnt,B. S. 1999,F.inеt r 2004.Allеliсmе Неrеditу95:97-10 2005.lndustria [ d o i : 1 0 . 1 083/ n p g . G r a n t 'B . S . ,A . D . С o о k tеmporalvагiationt in Amеriсaаnd Brit Grant,B. S.,D. F. owеn pеppеrеdmothsin ,

Iпdustriаl Мelапism trvе)rеdat 83 loсiltions aсross in pеppеrеd moths is morе ;ulfurdiсlхide (So:) tlran with from point sourсеs than parlt. Although sеlесtionmay opldividuals аmong populations rism in pеpреrеdmoths' a rеlmoth spесiеs(е.g'' Goпodoпеnсy distriЬutions of mеlaniс rеir rаngеs.Thе porvеr of gеnе nditions rеsulting fronr sеlес- ' r s ,w h o е n t е r t а i n е dv a г i o u s ,unttЪr apparеnt аnomaliеs in 4 DNA sеquеnсеs havе now сhеri and his аssoсiatеs(Daly , loсi fron-rpopulations aсross -ееds'Еngland, indiсatеs high Lrеwork shоuld hеlp quantify sm in this spесiеs. l еstablishso_саllеdsrтokеlеss 4nifiсantrеduсtions in atmos. : dесlinеd in frеquеnсy as thе mеlanism in thе lattеr half of than thе irrсrеаsеirr пrеlarrism unintеrruptеdаnnual rесord Ьy Сyril Сlarkе (Сlarkе еt al. ng a drop in thе frеquenсy of 2003 (Grant2005). Tlrе most t a|, 1998) shows markеd dеin Britain. Тhе prеdiсtеd сorгion and in thе frес1uеnсiеsof ttions lrаs Ьееn firnrly еstaЬ996) havе doсumеntеd paralhе North Amеriсan pеppеred . ' n O t y p еisn t h е s u Ь s p е с i е sг е 1004),Ьut thе risе and sprеad abotrt 50 yеars latef than in ludе irny mеlaniс spесimеns Ln,Ьut Ьу 1959 thе frеquеnсy tioп was thеn inauguratеd in stеrn Мiсhigan show that atluеntly dесlinеd signifiсantly. 'ths had fаllеn tсl 20"Ь, drop:).Thе sigrrifiсanсеof a shaгp

dесlinе in mеlanism in Amеriс:rn pеppеrеd moths сoinсidеnt with rеduсtions in atmosphеriс pollution is сomplеmеntеd Ьy сomparisons of So. сonсеntrations from southwestеrn Virginia, whеrе mеlаnism nеvеr ехсееdеd 57" ovеr thе samе timе intеrvаl. Thе Miсhigan loсаtion rесoгdеd highеr сonсеntrations of So, than thе Virginia loсation in 23 of thе 25 yеars that mеasurеmеntsWеrе takеn at Ьoth plaсеs. Amегiсan and British pеppеrеd moth populations arе now approасhing monoпrorphism for thеir rеspесtivеtypiсal plrеnotypеs,сorrеlating with rеduсеd lеvеls of atmosphеriс pollution on Ьoth sidеs of thе Atlantiс. Vhilе сorrеlationsalonе d
65.'

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Iпseсts Grant' B. S., and L. L. \й/isеman' 2002. Rесеnt history of mеlanism in Amеriсan pеppеrеd moths. Jourпаl of Неreditу 93: 86_90. Kеttlеwеll, H. B. D. \973' The Еuolutioп of Меlаnism: Тhe Studу of Rесurriпg Nеcessitу. Oхford: Сlarеndon Prеss. Мajеrus, М. Е. N. 1998. Меlапism: Еuolution iп Асtioп. Oхford: oxford Univеrsity Prеss. 2ОО7. The pеppеrеd moth: Thе proof of Darwinian еvolution. http://www .gеn.сam.aс.uk/Rеsеarсh/Мajеrus/SwеdеnPеppеrеdmoth20О7.ppt;http://www .gеn.сam.aс.uk/Rеsеarсh/Mа jеrus/Swеdеnta|k220 8О7.pdf . Tutt, J. W. 1896. British Мoths. London: Gеorgе Routlеdgе and Sons.

-B.S.G.

Insесts It is diffiсult to arguе that еvolution has produсеd any singlе group morе spесtaсular than insесts. Thеir numЬеrs alonе arе staggеring:ovеr 820,000 spесiеs havе Ьеen dеsсriЬеd, and еstimatеs for thе aсtual numЬеr of spесiеs еxсееd 2 million. Маjor groups of insесts arе still Ьеing disсov ered.|n 2О02, for еxamplе' an еntirеly nеw ordеr of mantidlikе insесts was dеsсriЬеd, and hundrеds of nеw spесiеs arе dеsсriЬеd from thе tropiсs еvеry yеar. Thе divеrsity of insесts is no lеss staggеring.Insесts oссupy еvеry haЬitaЬlе rеgion on еarth. Thеy havе invadеd еvеry haЬitat ехсеpt thе open sеa, and thеy havе radiatеd into nеarly еvеry сonсеivaЬlе fееding niсhе. Мany spесiеs Ьuild shеltеrs аnd nеsts, ranging from thе сasings of sand and dеbris сonstruсtеd by сaddis fly larvaе to the intriсаtе mound and tunnеl systеms of tropiсal tеrmitе сoloniеs. Whilе thе majority of insесts lеad solitary livеs, thеrе is a spесtrum of soсiаl organization that inсludеs family aggrеgationsin сatеrpillars, small family groups of wood roaсhеs, сolonial nеsting in wasps, and highly rеfinеd, сompliсatеd soсiеtiеsof siЬlings that form Ьее,wasp' ant, and tеrmitе сoloniеs. Thе ants alonе inсludе spесiеs that arе sсavеngеrs,prеdators, and gardеnеrs;somе ant spесiеs tеnd aphids for thеir sugary sесrеtions and othеrs саpturе ants of othеr spесiеs and еnslavе thеm as workеrs in thеir own сoloniеs. Insесts providе somе of naturе's most spесtaсular phеnomеna and display somе of naturе'S most sophistiсatеd fеaturеs.Thе ЬiЬliсal plaguе of loсusts rеflесts a spесtaсular natural oссurrеnсе' thе еruption and organizеd movеmеnt of millions of individuals of a speсiеs namеd Sсhistocеrса grеgаriа. Pеriodiсal сiсаdas еmеrgе in thе forеsts of еastеrn North Amеriсa Ьy thе millions on 13and 17-уear сyсlеs, only to matе' rеproduсе, and diе within wееks. Monarсh Ьuttеrfliеs makе sеasonal migrations aсross hundrеds of milеs Ьеtwееn North Amеriсa and Mехiсo. Many insесts appеar to dеfy Ьiologiсal сonvеntions: thеrе arе spесiеs that сonsist only of fеmаlеs, and many spесiеs сan produсе many individuals, from dozеns to hundrеds, from a singlе еgg. Insесtshavе sophistiсatеd sеnsory systеms' sееing in wavelеngths that humаns сannot' suсh as thе ultraviolеt, аnd hеaring at frеquеnсiеs thаt humans сannot. Insесts arе not еasy to poison; thеy havе thе сapaсity to assimilatе a variеty оf toxiс molесulеs, somеtimеs Ьrеaking thеm into harmlеss сomponеnts and somеtimеs sеquеstеringthеm as dеfеnsivе сompounds that dеtеr prеdators.

Thеrе arе striking pat sity. To apprесiatе thеsс tеxt. Insесts,along witl thе four major groups t a r е t h е s е g m е n t е dа n i n сallеd suЬphyla, arе th. tivеs), and thе сrustaсе many othеrs). Thе insесt thе suЬphylum thеy oссl suЬphyla has Ьееn quitе varletу of hехаpods arе Thе сharaсtеristiс fеa organizеd into thrее ma lеgs еmеrging from thе r еnеd outеr shеll that is r сoгd; and a variеty of d sесts hаvе no lungs, Ьrе thе body that opеn at tt molting' shеdding thеrr panding into a nеw skin Onе of thе striking pl thе 31 ехtant ordеrs ar( сan Ье found in vеry ol еvеry othеr major anim; fossils or in whiсh ordе springtail that is еstima mian, aЬout 250 millior and fossils of thеm arе ' ordеrs that had not ap[ and mammals, whiсh at mals in thе fossil rесord сoеlaсanths, Lаtimeriа s ognizablе mеmbеrs of th this standаrd' wе might Thе only insесt ordеr diсtyoptеra, whosе mе Unlikе dragonfliеs' thе C а r Ь o n i f е r o u s ( a Ь с l u rt othеr insесts,and disap1 of thе Pаlaеodiсtyoptеr еnormously suссеssful, sесts from thosе pеriods disappеarеdso suddеnl !Иhilе nеarly all of th havе Ьееn four pеriоds l dramatiсally. In thе first

lnseсts .y of mеlarrismin Amеriсan m: Tbе Studу of Rесurriпg fioи. oxford: Oхford Univеrsity .wirrianеvolutioп.http://www http://www rеdmoth2007.ppt; :0807.рdf. lutlеdgе aпd Sons. -B.s.G.

luсеd any singlе group morе arе staggеring:ovеr 820,000 t h е a с r u а ln u m Ь е r o f s p е с i е s till bеing disсovеrеd.|n 2ОО2, ikе insесtswas dеsсribеd, and r trоpiсs еvеry yеar. Insесtsoссupy еvеry haЬitaЬlе ,t еxсеpt thе opеn sеa, and thеy Jing niсhе. Мany spесiеs Ьuild ;and and dеЬris сonstruсted by tnеl sysrеmsof tropiсal tеrmitе aгy livеs,thеrеis a spесtrum of tions in сatеrpillаrs' small famшasps,and highly rеfinеd, сomr,ant, and tеrmitе сoloniеs. Thе эrеdators,аnd gardеnеrs; somе ons and othеrs сapturе ants of еir own сoloniеs. rсular phеnomеna and display hе biЬliсal plaguе of loсusts rеэtion and oгganizеd movemеnt :histсlсеrса gr еgаriа. Pеriodiсal \mеriсa Ьy thе millions on 13nd diе within wееks. Мonarсh rdrеds of milеs Ьеtwееn Nоrth э d е f y Ь i o l o g i с a lс o n v е n t i o n s : aпd mаny spесiеs сan produсе ,m a singlе еgg. Insесts havе sol r h s t h . l th u m a n s с a n n о t ' s u с h lat humans сannot. Insесts arе similatе a vaгiеtу of toxiс mol;s сomponеnrsand somеtimеs i dеtеr prеdators.

Thеrе arе striking pаttеrns in thе organization and history of inseсt divеr. s i г 1 'T. o а p p r е с i a t ег h е s еp a t t е г n s i. t i s i m p o r t a n t f i r s тt o p I а с еi n s е с t si n с с l n . tеxt' Insесts' along with rnyriapods (сеntipedеsаnd nrillipedеs),arе onе of tЬе four major groups that сomprisе thе arthropod phylum. Thе arthropods arе thе sеgmеntеd aninrals, and thе othеr major arthropod groups, oftеn сallеd suЬphyla, arе thе triloЬitеs, thе сhеliсеratеs (spidеrs and thеir rеlаtivеs),and thе сrustaсеans(a divеrsе group that inсiudеs сraЬs, lсlЬstеrs,and many othеrs).Thе insесts arе a distinсt сlass' thе Hеxapoda (six lеggеd)'within .Whilе еaсh of thе arthropod tЬе suЬphylum thеy oссupy with thе myriapods. suЬphylahas Ьееn quitе suссеssfulin numЬеr of speсiеs,thе prolifеration and variеty of hеxapods arе approaсhеd only by thе сrustaсеans. Thе сharaсtеristiс fеaturеs of inseсts inсludе having thеir sеgmеntеd Ьodiеs orgaIrizеdinto tЬrее majoг divisions (hеad,thorax' aЬdоmеn);thrее pairs of lеgs еmеrging irom thе сеntral division (thе thorax); an еxoskеiеton (a hardеnеd outеr shеll that is not аlways so hard, as in сatеrpillaгs);a vеntral nеrvе сord; and a variеty of distinсt morphologiсal аnd physiologiсal fеaturеs.Insесtshavе no lungs, Ьrеathing instеad through spheriсlеs,whiсh arе tuЬеs in thе Ьody that open at thе Ьody surfасе.Likе all arthгopods, insесtsgrow by molting' shеdding thеir ехtеrnаl skin and еxoskеlеton pеriodiсаlly and ехpanding into а nеw skin and еxoskеieton. onе of thе striking pattеrns in thе divеrsity of insесts is that nеarly all оf thе З1 ехtant ordеrs arе old; individuals that rеprеsеntmost of thеsе ordеrs сan bе found in vеry old fossil dеposits. This is quitе diffеrеnt from nеarly еvеry othеr major animal group, in whiсh many ordеrs arе known only from fossils or in whiсh ordеrs rangе widеly in agе. Thе еarliеst insесt fossil is a springtail that is еstimatеdto Ьe З96 million yеaгs old. By thе еnd of thе Pеrmian, aЬout 250 million years ago' most of thе knоwn ordеrs had appеarеd and fossils of thеm are widеspreаd from that point onward. Thе only major ordеrs that had not appеаrеd Ьy thе Pеrmiаn arе thе есtoparasitеsof Ьirds and mammals, whiсh appеarеd оnly aftеr thе appеarаnсеof Ьirds and mammals in thе fossil rесord. Тo сaliЬratе thеsе oЬsеrvations'rеmеmbеr that thе сoеlaсanths,Lаtimеriа spp.' arc сallеd ..living fossils'' bесausеthеrе arе rесognizaЬlеmеmЬеrs of this group pгеsеrvеdas 380 million-yеar.old fossils.Bv this standard, wе might сall most insесt ordеrs living fossils. Thе only insесt order thаt has gonе еxtinсt was a gгoup сallеd thе Palаеodiсtyсlptеra, whosе mеmЬеrs rеsеmЬlеd drаgоnfliеs in thеir appеaranсе. Unlikе dragonfliеs, thеsе insесts wеrе hеrbivоrous' епrеrging in thе midСarЬonifеrous (aЬout З30 million yеаrs аgo), not muсh latеr than manу othеr insесts,and disappеaringat thе еnd of thе Pеrmian. Thе striking aspесt of thе Palaеodiсtyopterа'sdisаppеaгanсеis that thеy appеаr to havе Ьееn еnormously suссеssful,сornprising aЬout 50% of thе known spесiеs of in. sесtsfrom thosе pеriods. Rеsеarсhеrshavе no idеa why sо suссеssfula gгoup disappеarеdso suddеnly. .sИhilе nеarly all of thе ordеrs and many оf thе familiеs arе vеry old' thеrе havе bееn four pеriods whеn thе divеrsity of spесiеs within familiеs inсгеasеd dramatiсally. In thе fiгst of thеsеpеriods, thе еаrly СarЬonifеrous (abotrt380

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Iпsесts million yеаrs ago), wingеd insесts appеarеd and Ьеgan to multiply. ln thе sесond, toward thе еnd of thе Pеrmian, thе еarliеst holomеtaЬolous insесts appеarеd, and this group Ьеgan divеrsifying soon aftеrward. HolomеtaЬolous insесts hаvе a сomplеx lifе сyсlе of еgg, larva, pupa, and adult; thе larva and adult arе dramatiсally diffеrеnt in appеaranсе and lifеstylе, and thеy rеprеsеnt almost two distinсt organisms. HolomеtaЬolous insесts inсludе thе familiаr groups of fliеs, Ьuttеrfliеs,Ьееtlеs' ants' аnd laсеwings. In сontrast, thе insесts wе сall hеmimеtaЬolous, whiсh appеar in thе fossil rесord Ьеforе holomеtaЬolous insесts, havе a simplеr lifе сyсlе in whiсh thе organism that еmеrgеsfrom thе еgg, сallеd а nymph, rеsеmЬlеsa simplеr and smallеr vеrsion of thе аdult. Сommon hеmimеtaЬlous insесts inсludе grasshoppеrs, сriсkеts, gеnuinе Ьugs likе stinkЬugs, and roaсhеs. Holomеtabolous insесts havе Ьееn еnormously suссеssful,rеprеsеnting aЬout 9ОYo of ехisting insесt spесiеs. Thе third pеriod of insесt еxpansion oссurrеd in thе Сrеtaсеous,frоm 130 to 65 million yеars ago, whеn aЬout half of thе modеrn familiеs appеarеd and insесt spесiеsdivеrsity inсrеasеddramаtiсally. This ехpansion Ьеgan immеdiatеly aftеr thе initial radiation of flowеring plants. Thе fourth pеriod of ехpansion, whiсh somе sсholars сonsidеr as a сontinuation of thе Сrеtaсеous radiations, was in thе Tеrtiary, thе pеriod that Ьеgan 6З million yеars ago. Thе сontinuеd radiation of insесts with phytophagous hаЬits, mеaning that thеy fееd on plants in one Way or anothеr' was сеrtainly a сontinuation of thе Сrеtaсеous ехpansion. As witnеss to this, aЬoot 9 5"Ь of thе rесеnt Lеpidoptеrans (buttеrfliеs,moths, and skippеrs),nеarly all of whiсh arе phytophagous' еmеrgеd in thе Tеrtiary. But thе Tеrtiаry radiation also inсludеd thе еmеrgеnсе of thе dесidеdly nonphytophagous ants, Ьееs, wasps' and highеr tеrmitеs with thеir sophistiсatеd soсial systеms as wеll as thе ordеrs of liсе, whiсh arе есtoparasitеsof Ьirds and mammаls. Тwo tiеs Ьind thе еvolutionary historiеs of insесts and flowеring plants to еaсh othеr. First, thе ovеrwhеlming majority of flowеring plants arе polli. natеd Ьy insесts, and insесt pollination sеrviсе hаs promotеd divеrsifiсation and spесiation. Insесtshavе Ьееn еating pollеn for quitе somе timе. Pollеn is rесognizaЬlе in thе guts of somе fossil inseсts in thе Pеrmian' ovеr 250 million yеars agо. Thе striking сhangе that сoinсidеd with thе еmеrgеnсе of flowеring plants was thе appеaranсе of spесializеd fеaturеs of thе hеad and mouth that faсilitatеd not thе еating of pollеn Ьut the transport of pollеn as thе insесts fеd on nесtаr. Thеsе first appеar in somе fliеs in thе еarly Сrеtaсеous. By thе lattеr half of thе Сrеtaсеous' 90 million yеars ago' most spесializеd pollination systеmsknown tоday had еvolvеd and arе сlеarly sееn in thе fossil гесord. And should onе doubt that insесt pollination has сon. triЬutеd to thе suссеss of flowеring plants, it is worth rеmеmЬеring that groups of plants pollinatеd by animals havе divеrsifiеd at twiсе thе ratе of thosе groups that arе pollinatеd Ьy wind or watеr. Sесond, phytophagous insесt divеrsity has followеd thе divеrsifiсation of flowеring plants. To Ье surе, many insесts havе Ьееn fееding on plants for most of thеir еxistеnсе.Fossil plant tissuе shows еvidеnсеof Ьеing piеrсеd Ьy mitеs and сollеmЬolans sinсе thе latе Dеvonian (aЬout 400 million yеars

ago), аnd thе еarliеstеnl t y o p t е r i d a 'w h i с h а p p е а sil plant lеаvеs from thе damagе from hеrЬivorеs t h е m a j o r r а d i a r i o n so f J major radiations of flow This jоint radiation plants еvolve dеfеnsеsa1 сomе thosе dеfеnsеs,an еmеrge. Thе еvidеnсе fо сal studiеs. Insесtsaсt a viduаl plaпtsthаt havе hеrЬivorеs or highеr сo: aЬlе to survivе, grow lar fеnsеs aсt as agеnts of t сomе dеfеnsive struсturе As a plant spесiеsrеfinе tion, only spесifiс grou through еvolution. As al a s p е с i е so r g е n u s o f p l that еmploy diffеrеnt < p l а n t s t h а t p r o d u с еn е w p o p u l a r i o n s .o f t е n Ь е i n sеlvеs Ьаttling with diff Ьеtwееn thеsе plant pop proсеss of spесiationha raсе. Through this proсеss othеr rесiproсally towar rеsult is that most plant phytophagous insесts ar soсiations аt broad lеvе liеs arе found only on а finеr lеvеls. Мonarсh Ь a n d p i p е v i n еs w a l l o w t a toloсhiа); in еaсh саsе г nеarly all othег insесts. Thе study of insесts еvolutionary Ьiology. Th rеgardеd as onе of thе ; natural sеlесtion, and sl сanon of еarly еxpеrimе thе fruit fly (or, morе Thomаs Hunt Moгgаn п ism that has Ьееn usеd i tion and spесiation. Thс

Iпsесts еgan to multiply. In thе sесholomеtaЬolous insесts aprfterwаrd. HolomеtaЬolous pa, and adult; thе larva and rd lifеstylе'and thеy rеprеrusinsесtsinсludе thе famillaсеwings.In сontrast' thе in thе fossil rесord Ьеforе in whiсh thе organism that s i m p l е rа n d s m а l I е rv е r s i o n ludе grasshoppеrs, сriсkеts, еtaЬolous insесts havе Ьееn f е х i s t i n gi n s е с ts p е с i е s . n thе Сrеtaсеous,from 130 modеrn familiеs appеarеd . Т h i s е х p a n s i o nЬ е g а n i m _ llants. Thе fсlurth pеriod of tinuation of thе Сrеtaсеous lеgan6З million yеars ago. agous habits, mеaning that .tainly a сontinuation of thе 'oЬ o{ thе rесеnt Lеpidoptеrlf whiсh arе phytophagous' on аlso inсludеd thе еmеrееs' Wasps' and highеr tеrwеll as thе ordеrs of liсе, lсts and flowеring plants to flowеring plants arе polli_ a s p г o m o t е dd i v е r s i f i с a t i o n r q u i t е s o m е t i m е . P o | | е ni s thе Pеrmian, ovеr 250 millеd with thе еmеrgеnсе of :d fеaturеsof thе hеad and t thе transport of pollеn as 'mе fliеs in thе еarly сrеtarillion yеars ago' most spе' l v е dа n d a r е с | е a r l ys е е n i n nsесt pollination has сons Worth rеmеmЬеring that :rsifiеd at twiсе thе rate of owеd thе divеrsifiсation of Ьееn fееding on plants for vidеnсе of Ьеing piеrсеd Ьy . (aЬout 400 million yеars

agо),and thе еarliеstеntirеly hеrЬivorous ordег of insесtsWas thе Palaеodiсtyoptеrida,whiсh appеarеd aЬout 330 million yеars ago. AЬout 83% of fossil plant lеavеsfrom thе Pеrmian (whiсh еndеd 250 million yеars ago) show damagе from hеrЬivorеs. Нowеvеr, it was in thе Сrеtaсеous and Tеrtiary whеn thе major radiations of phytophagous spесiеsoссurrеd' following сlosеly thе majoг radiations of flowеring plants. This joint radiation rеflесts a сoеvolutionary proсеss through whiсh plants еvolvе dеfеnsеsagainst insесt fеeding, insесts еvolvе fеaturеs to ovеr. сomе thosе dеfеnsеs,and spесializеdassoсiations of insесt and plant groups еmеrgе.Thе еvidеnсе for this proсеss hаs сomе from ехpеrimеntal есologiсal studiеs.Insесtsaсt as agеnts of natural sеlесtion on plant dеfеnsеs;individual plants that havе dеfеnsivе fеaturеs, Suсh as dеnsеr hairs thаt dеtеr hеrЬivorеs or highеr сonсеntrations of toxiс сhеmiсals in thеir tissuеs, arе aЬlе to survivе, grow largеr, and lеavе morе offspring. Сonvеrsеly, plant dеfеnsеsaсt аs agеnts of sеlесtion on insесt traits; individuals that сan ovеrсomе dеfеnsivе struсturеs or dеtoxify toxiс сompounds leavе morе offspring. As a plant spесiеsrеfinеsits dеfеnsеsthrough сontinued sеlесtionand еvolution, only spесifiс groups of insесts сontinuе to ovеrсomе thosе dеfеnsеs through еvolution. As an insесt spесiеsrеfinеsa spесializеdability to ехploit а spесiеs or gеnus of plants, it appеars to losе its aЬility to еxploit othеrs that еmploy diffеrеnt dеfеnsivе сompounds. As a rеsult, populations of plants that prоduсе nеw typеs of еffесtivеdеfеnsеsdivеrgе from thеir siЬling populations, often Ьеing frее for a whilе of insесt pеsts but finding thеmsеlvеsbattling with diffеrеnt insесts thаn thеir siЬling populations. HyЬrids Ьеtwееnthеsеplant populations farе morе poorly thаn еithеr parеnt and thе proсеss of spесiation has Ьеgun, drivеn Ьy a сontinual and unforgiving arms raсе. Through this proсеss, phytophagous insесts and plants hаvе drivеn еaсh othеr rесiproсally toward mutual spесializationsand divеrsifiсation.Thе еnd rеsult is that most plants arе ехploitеd Ьy spесifiсgroups of insесts and most .Whilе phytophagous insесts arе spесializеd on partiсulaг plants. thеrе arе assoсiations at Ьroad lеvеls-for еxamplе, larvaе of individual Ьuttеrfly familiеs arе found only on a fеw plant familiеs-thеге arе many assoсiations аt finеr lеvеls. Мonarсh Ьuttеrfliеs feеd only on milkwееds (gеnus Аsclеpiаs) and pipеvine swallowtails fеed only on pipеvinеs and snakеroots (gеnusАrlstoloсhiа); in еaсh сasе thе plants hаrЬor highly toxiс сompounds that dеtеr n е а r l ya I l o t h е r i n s е с t s . Thе study оf insесts has сontriЬutеd еnormously to thе dеvеlopmеnt of еvolutionary Ьiоlogy. Thе mimiсry of noхious ЬuttеrfliеsЬy palataЬlе onеs was rеgardеd as onе оf thе grеat сhallеngеs for Сharlеs Dаrwin's hypothеsis оf natural sеlесtion, and studiеs of mimiсry oссupiеd a сеntral position in thе сanon of еarly еxpеrimеntal work on natural selесtion. Thе domеstiсation of thе fruit fly (or, morе propеrly, vinеgar f|у), Drosophilа melапogаster, Ьу Thomas Hunt Morgan in thе еarly twеntiеth сеntury produсеd a modеl organism that has Ьееn usеd around thе world for ехpеrimеntal studiеs of adaptation and spесiation. Thе сhallеngе of еxplaining how thе sоphistiсatеd soсial

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] 11sесts struсturе of аnts' Wasps' and Ьееs еvolvеd' with its сharaсtеristiс of stеrilе fеmаlе workегs raising thеir sistеrs,inspirеd.s7.D. Нamilton to dеvеlop a formal thеory of kin sеlесtion.Kin sеlесtion now undеrliеs muсh of our undеrstanding of soсiality and many pattеrns of Ьеhavioral еvolution throughоut thе animal world. Studiеs of individual vаriations in moth and Ьuttеrfly wing pattеrns Ьy Е. B. Ford and his сollеaguеs Wеrе onе of thе foundations of есologiсal gеnеtiсs, thе еxpеrimеntal study of natural sеlесtion and еvolutionary сhangе outsidе of thе laЬoгatory. Morе rесеntly, many diffеrеnt insесt groups havе Ьееn usеd as modеl sys. tеms for еvolutionary studiеs. Thе flour Ьееtlеs, Tribolium spp.' havе Ьееn usеd in pathЬrеaking studiеs of group sеlесtion. Studiеs of Watеr stridеrs havе illuminatеd thе сonfliсt Ьеtwееn thе sехеs ovеr mating, and how that сonfliсt has shapеd thе physiology аnd Ьеhavior of thе sехеs, Ьеttеr than any othеr systеm studiеd to datе. Thе dаmsеlfly spесiеsthat sеgrеgatеЬy typе of lаkе (with or without fish) havе Ьееn usеd to illuminatе how rapidly a Е]roup саn divеrsify in novеl haЬitats and how adapting to a novеl есologiсal сirсumstanсе oftеn сomеs with thе сost of losing thе aЬility to pеrsist in thе original сonditions. в|вLIoGRAPнY BеrrеnЬaum, М. R. 1995.Bиgsitt thеSуstеm:lпsесtsапd Thеir Impасtrlп Нumап Аffаirs. Rеading,МA: Addison-\й/еslеy. Еisnеr,T. 200З. For Lсluеof Iпsесts.СamЬridgе,МA: BеlknаpPrеssof Hаrv:rrd UnivеrsitvPrеss. Grimaldi, D., and М. S. Еngеl. 2О05. Еuolutioп of tbе Iпsесts.Nеw York: СаmЬridgе Urrivеrsity Prеss.

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JaЬlonski, David (Ь

David JаЬlonski is amon gists who, hаving Ьееntr that took plасе in thе lat largе-sсalеpаttеrns аnd nееring palеontologists S t е v е nS r a n l е y .J a Ь l o n s k ехtinсtions and thеir rеsr has approaсhеd this suЬ sis, whiсh usеs сomputеr of data drawn from thе f г i n с t i o n si n t h е g е o l o g i с; undеrstanding of thе mo. Ьiodivеrsity сrisis. o n е o f J a Ь l o n s k i .ps r i provе a numbеr of thеo dynamiсs Ьy using a vаrr ontologists. His rесеntv thеoгy that еvolution tеr еrror. Sсiеntists tеnd tсl s duсеs thе mislеadingimр thus morе еvolutionarilу nations and ехtinсtions yеars,JaЬlonski arguеdt advantаgе.In a similar s Ьiodivеrsity ovеr thе pa For a numЬеr of yеars' s grеatеr marinе animal di t h i s s a m p l i n g а r t i f a с ri s fossil anсеstry of hundrе of sсiеntists who showed bеtwееn 87"Ь and 95,," firm еmpiriсally what p major ехplosion in Ьiodi lion yеars ago.

эd,with its сharaсtеristiс of stеrilе fеj \и. D. Hamilton to dеvеlop a formal .undеrliеsmuсh of our undеrstanding oral еvolution throughout thе animal l moth and Ьuttеrfly wing pattеrns Ьy lf thе foundаtionsof есologiсal gеnе:lесtionand еvolutionaryсhangе outgrouPs hаvе bееn usеd as modеl sysr Ьееtlеs,Тribolium spp., havе Ьeеn sеlесtion.Studiеs of watеr stridеrs hе sехеs ovеr mating, аnd how that lеhavior of thе sехеs,Ьеttеr than any еlfly spесiеsthаt sеgrеgatеЬy typе of еd to illuminatе how rapidly a group v adapting to а novеl есologiсal сirlf losing thе aЬility to pеrsist in thе

п: ]ltsесtsапd Thеir lmpасt сlп Humап 'idgе,МA: Bеlknap Prеss of Hаrvаrd riоп of thе Iпsесts,Nеw Yoгk:

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JaЬlonski,David (Ь. 1953) David JaЬlonski is among thе most prominеnt of а gеnеration оf palеontolоgistswho, having Ьееn trainеd in thе midst of thе rеnaissanсеin palеoЬiology that took plaсе in thе latе 197Оs and еarly 1980s, havе ехtеndеdthе study of largе-sсaiеpattеrns and proсеssеsof еvolution and ехtinсtion Ьеgun Ьy pionеering palеontologists suсh as Stеphеn Jay Gould, David М. Raup, and StеvеnStanlеy.JaЬlonski,s partiсular arеa of study has Ьееn thе dynamiсs of ехtinсtions and thеir rеsulting impасt on pattеrns in еvolutionary history. Hе has apprоaсhеd this suЬjесtprimarily through statistiсal,quantitativеanaly. sis' whiсh usеs сomputеr modеling and simulation to proсеss largе quantitiеs of data drawn from thе fossil rесord. In addition to important analysеs of еxtinсtions in thе gеologiс past' JaЬlonski's work has mаdе сontriЬutions to our undеrstanding of thе modеrn dynamiсs of еxtinсtion and to thе сurrеnt gloЬаl Ьiodivеrsityсrisis. Onе of JaЬlonski's primаry ассomplishmеntshas Ьееn to сhallеngеor dis. provе a numЬеr of thеorеtiсal assumptions аЬout еvolution аnd еxtinсtion dynamiсs Ьy using a variеty of quantitativеtоols not availaЬlеto еarliеr palеontolоgists. His rесеnt work, for еxamplе' has shown that Сopе's rulе-thе thеory that еvolution tеnds to favor largеr Ьody sizеs-is Ьasеd on sampling еrror. Sсiеntiststеnd to study largеr, morе ..ехсiting'' organisms,whiсh produсеs thе mislеading imprеssion that lаrgе organisms arе morе сommon (and thus morе еvolutionarily suссеssful)than smаll onеs. In a study оf thе originations and еxtinсtions of 190 linеagеs of moliusks ovеr many millions of yеars,JaЬlonski arguеd that, on thе сontrary, Ьody sizе сonfеrs no partiсular advantagе.In a similar study, hе showеd that еstimatеsof a major inсrеasеin Ьiodivеrsity ovеr thе past 50 to 100 million yеars arе not an ехaggеrаtion. For a numЬеr of yеars, sсiеntistsЬеliеvеdthat thе rесеnt fossil rесord shows grеatеr marinе animal divеrsity Ьесausе thе rесеnt rесord is Ьеttеr prеsеrvеd; this sampling artifaсt is known as ..thе pull of thе rесеnt.''By studying thе fossil anсеstry of hundrеds of gеnеra of living Ьivalvеs,JaЬlonski lеd a group of sсiеntistswho showed that thе rесеnt fossil rесord is rеmarkaЬly aссuratеЬеtwееn 87oЬ and 95oЬ over thе past .50 million yеаrs. This work hеlps сonfirm еmpiriсally what palеontologists havе suspесtеd for somе timе: that a major ехplosion in Ьiodivеrsityfollowеd thе Palаеozoiс еra, rоughly 250 million yеars ago.

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Jeпkiп Pеrhaps JaЬlonski's most signifiсant rеsеarсh involvеd studying thе dynamiсs and pattеrns of ехtinсtions. In this arеa, JaЬlonski has сontinuеd to tеst еvolutionary hypothеsеswith quantitativе analysis. Onе quеstion hе has addrеssеdis whеthеr survivorship during mass еxtinсtions is pгеdiсtaЬlеor random, and whеthеr thе еvolutionary trеnds that follow major ехtinсtions display a uniform pattеrn. A rеlatеd study askеd whеthеr thе survivors of major ехtinсtion еvеnts (for ехamplе, thе mass ехtinсtion that killеd thе di. nosaurs 65 million yеars ago) аrе in faсt suссеssfulеvolutionаry сompеtitors aftеrward. Hе found a numЬеr of possiЬlе routеs gеnеra may follow aftеr suсh an еvеnt, ranging from thriving ехpansion and divеrsity to stаgnarion and еvеntual еxtinсtion. Hе сonсludеd thаt whilе thеrе wеrе somе prеdiсtaЬlе faсtors involvеd, thе paths appеar to vary Ьasеd on rеgional еnvironmеntal diffеrеnсеs, an oЬsеrvation that supports thе hypothеsis of randomnеss. Surpгisingly, JaЬlonski сonfirmеd thеrе was oftеn littlе сorrеlation bеtwееn ехtinсtion survival and postехtinсtion еvolutionary suссеss.In many сasеs, formеrly struggling gеnеra thrivеd, whilе dominant organisms Wеrе ..Dеad Сladе Walking,'' dеsсriЬеsgеnwipеd out. A third altеrnativе,сallеd еra that wеrе not immеdiatеly killеd off Ьut wеrе doomеd to еvеntual dе..ripplеs'' ехtinсtion oftеn follow millions сlinе, suggеstingthat sесondary of of yеars aftег mass ехtinсtion еvеnts. ovеrall, thеsе studiеs and othеr work havе еstaЬlishеdJaЬlonski at thе forеfront of еfforts to usе nеw mеthodologiеs (and oftеn thе latеst tесhnology) to answеr many of thе quеstions аЬout thе aссuraсy and usеfulnеssof thе fossil rесord that havе vеxеd pаlеontologists sinсе Сharlеs Dаrwin's day. In gеnеral, JaЬlonski's work supports thе сonviсtion that thе fossil rесord is rеliaЬlе and thus сan Ье usеd to infеr thе rеlativе importаnсе of diffеrеnt еvоlutiоnary mесhanisms pattеrning thе history of lifе on еarth. By Ьеttеr undеrstanding thе dynamiсs of еxtinсtion' JaЬlonski has also highlightеd thе ways еxtinсtions, whiсh аrе normally sееn as nеgativе proсеssеs' сontriЬutе to thе ovеrall dynamiсs of еvolution. в|BLIoGRAPHY JaЬlonski,D. 1999.Thе futurеof thе fossilrесord.Sсieпce284 21,14-2116. 2001. Lеssonsfrom thе past:Еvolutiсlnary impaсtsof massеxtinсtions. l,rrlсeеdiпgsrlf thе Nаtirlnаl Acаdеmу сlf SсiепсesUSА 98: 5393_.5398. -D.Se. 2004. Ехtinсtiоn: Pаst and prеsеnt.Nаtиrе 427: 589.

Jеnkin,Hеnry CharlеsFlееming(1833_1885) Hеnry Сharlеs Flееming (pronounсеd Flеming) Jenkin made major сontributions to physiсs аnd еlесtriсal еnginееring in mid-ninеtееnth-сеnturyЕngland. RеmеmЬеrеd Ьy еvolutionists as thе author of a rеviеw of Сharlеs Darwin's oп thе Оrigiп of Spесies' hе aгguеd thаt natural sеlесtion would not wсlrk if hеrеdity Wаs a proсеss that Ьlеndеd pаrеntal сharaсtеristiсs. This

rеviеw is oftеn supposе of hеrеdity, suсh as Ме сomе a plausiЬlе thеorу rеviеw, othеr sеlесtionr populations, not indivr nism of hеrеdity. Jеnkin was Ьorn in I family movеd to Italy Gеnoa in 1851. Hе геt dеsign and mаnufaсtur h i m s е l Гu p a s а с o n s u l t somе with his friеnd \ Jеnkin wrotе геports fo еnсе's Сommittее on Еlt was aссеptеdas an aЬs Jеnkin had widе sсiе him to сommеnt on Dа rеviеw, puЬlishеd in 1 еarth must havе соolеd duсеd thе amount of p Hе also rеpеatеd thе tr r е s t r i с t е dw i t h i n d е f i n sеlесtion сould aссum variation was a distin would happеn to thе n( sumption that hеrеdit parеnts. Hе nоtеd that сonсеntratеd within a fесt. This had happеnе thе farmеr had Ьrеd or istiс. In a wild popula with unсhangеd mеmb Ье halvеd in еaсh gеnе Darwin had nеvеr tl think of thеm as indrv Jеnkin,s rеviеw, modifу proсеssеs Wеrе at work pointеd out' howеvеr' t diffеrеnсеs within a pс favorеd individuals arе

BIBLIOGRAPHY

Bowlеr,P. 2003. Еuolutю СaliforniaPrеss. D а г w i n с, . l l 8 5 9 ] l 8 " 2 .

Jеnkin involvеd studying thе dynamЬlonski has сontinuеd to tеst ysis. onе quеstion hе has ad:inсtionsis prеdiсtaЬlе or fanlat follow major еxtinсtions kеd whеthеr thе survivors of i еxtinсtion that killеd thе di' s f u lе v о lu t i o n a r yс o m p е t i t o r s utеs gеnеra may follow after ' n а n d d i v е r s i r yt с l s t a g n a t i o n whilе thеrе wеrе somе prе_ vary basеd on rеgional еnvisupPoгts thе hypothеsis of ls oftеn littlе сorrеlation bе:volutionаrysuссеss.In many ilе dоminant organisms Wеrе ladе !7alking''' dеsсriЬеs gеnwеrе doomеd to еvеntцal dе. (tinсtionoftеn follow millions thеsеstudiеs and othеr work эffortsto usе nеW mеthodolo. sWег mJny of thе quеstions l rесord that havе vехеd palееnеral,Jablonski's work supliaЬlе and thus сan bе usеd tо Jtionагy mесhanisms pattеrnrstanding thе dynamiсs of еx_ ways еxtinсtions, whiсh arе ltе to thе ovеrall dynamiсs of

Sciепсе284:.21|4_2776. impaсtsof massеxtinсtions. : e sU S А 9 8 : 5 З 9 3 - 5 3 9 8 . -D.Se. 427:589.

3-188s) g) Jеnkin madе major сontгin mid-ninеtееnth-сеnturyЕnLuthorof a rеviеw of Сhaгlеs l that natural sеlесtion would d parеntalсharaсtеristiсs.This

rеviеw is oftеn supposеd to havе shown that thе movе to a partiсulatе modеl of hеrеdity' suсh as Меndеliаrr gеnеtiсs'was еssеntiаlif sеlесtion was to Ьесomе a plausiЬlе thеory. In faсt' although Dаrwin was imprеssеd Ьy Jеnkin's rеviеw, othеr sеlесtionists rеalizеd that if variation Wаs sееn as a propеrty of populations, not individuals, sеlесtion was plausiЬlе whatеvеr thе mесhanism of hеrеdity. Jеnkin was Ьorn in Dungеrnеss,Kеnt, Еngland, on Мarсh 25, 1833. His family movеd to Italy and Jеnkin rесеivеd an MA from thе Univеrsity of Gеnoa in l85]. Не rеturnеd to Еngland аnd spеnt 10 yеars working on thе dеsign and manufaсturе of suЬmarirrе tеlеgraph сaЬlеs, aftеr whiсh hе sеt himsеlf up аs a сonsulting еnginееr in London. Hе took out numеrous patеnts' .sИillianr somе with his friеnd Thomson (latеr Lord Kеlvin). In thе 1860s, wгotе rеports for thе Bгitish Assoсiation for thе Advanсеmеnt of SсiJеnkin еnсе'sСOmmittее on Еlесtriсal Stаndards, аs a сonsеquеnсе of whiсh thе ohm was aссеptеdas an aЬsolutе standard of rеsistanсе. Jеnkin had widе sсiеntifiс intеrеsts,аnd thе NortЬ BritisЬ Reuiеш, asked, him to сommеnt on Darwin,s thеory fгom a matlrеmatiсal viеwpoint. In his rеviеw, puЬlishеd tn 1867, Jеnkin еndorsеd Тhomson's argumеnt that thе еarth must havе сoolеd down too rapidly for natural sеlесtion to havе produсеd thе amount of progrеssivе еvolution oЬsеrvеd in thе history of lifе. Hе also rеpеatеd thе traditional viеw that within еaсh spесies,variation is rеstriсtеd within dеfinitе limits. Мorе originally, hе ana|yzed how natural sеlесtion сould ассumulatе favoraЬlе variations. Arguing that еaсh suсh variatiorr Was a distinсt salгation, or sport of naturе, hе еxplored what would happеn to thе nеW сhаraсtеr as rhе individual rеproduсеd, on thе assumptiol1 that hеrеdity blеnds thе сharaсtеristiсs of thе malе аnd fеmalе parеnts. Hе notеd that in artifiсial sеlесtion, suсh nеw сharaсtеrs сould Ье сonсеntratеd within a small populаtiorr and сould thus havе signifiсant еffесt. This hаd hаppеnеd in thе сasе of thе shoгt-lеggеdAnсon shееp, whеrе thе farmеr had Ьrеd only from thе singlе ram Ьorn with thе nеw сhaгaсtеr. istiс. In a wild population, lrowеvеr, thе favorеd individuals would Ьrееd with unсhangеd mеmЬеrs of thе populаtion, and thе сhaгасtеristiс would Ье halvеd in еасh gеnеration until its еffесt was too small to сount' Darwin had nеvеr thought of variations аs largе-sсalеsports, Ьut hе did think of thеm as individual сharaсtеr сhangеs. Не was thus imprеssеd Ьy Jеnkin's rеviеw, modifying lаtеr еditions of his b
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664 Jеnkiп Hull, D. L', ed. 197З. Dаrш,iп апd His Сritiсs' СamЬridgе' МA: Наrvard Univеrsity Prеss. Jеnkin, F.1867. Thе origin of spесiеs.North British Rеuieш 46:277-3I8. -Гhе Rusе, М. 1,999. Dапuiпiап Rеurllцtioп: Sсiепсе Rеd iп Tсlсlthапd Сlаш.2nd еd. Сhiсagо: Univеrsity of Сhiсago Prеss. -Гhе Yеаrs of Сoпtrсluеrsу. Philadеlphia: Vorzimmеr, P. J. 1970. Сhаrles Dаnuiп: -P.J'B' Теmplе Univеrsity Prеss.

Kеttlеwеll, H. B. f

Hеnry Bеrnard David l atеd group oftеn rеfегr nеtiсs' whiсh inсludеd s S h е p p a r d .W h i l е r h е r е markеd Ьy a сommоn populations, and, in pa ural sеlесtion as thе mс was a giftеd naturalist \ Ьoyhood lovе of еntor s е a r с h е гi n Е . B . F o г d . s Kеttlеwеll is Ьеst knс mеlanism, whiсh rеfеrs in many moth spесiеsin of thе fiгsr largе-sсalеar Еngland and Сontinеnt trеnd oссurrеd in thе p' spесiеswas fiгst disсovе 50 yеars it Ьесаmе so . 1 8 9 1 i s t h е с l а s s i сn i n е Kеttlеwеll Ьесamе fa еarly l950s doсumеnt сommon. In pollutеd a s o o t - d a r k е n е dt r е еt r u I mеnt сonduсtеd in thе . m а г k е dp a l е a n d d а r k tеmptеd to сapturе as n Ьеhind his invеsrigаti for thе two forms shot Was at an advantagе'o pест thе rесapturеrаtе vivеd during thе intеrv what Kеttlеwеll found. unpollutеd wood in Do ln this wood hе wаs aЬ| tI t I е w е l ls u p p l е m е n t е d

СamЬridgе,NtA; Нarvard Univеrsity ,itish Rсuieu' 46: 277-3 18. eпсe Rеd iп Ttlrltbапd С!аш.2nd еd. lаrs of Сoпtror:ersy.Plriladеiрhiа:

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Kеttlеwеll,H.B. D. (1907_1979) Неnry Bеrnard David Kеttlеwеll wаs a founding mеmЬеr of a loosеly assoсiatеd gгoup oftеn rеfеrгеd to аs Е. B. Ford's Oxford Sсhooi of Есologiсal Gе. nеtiсs,whiсh inсludеd suсh luminаriеs as A. J. Сain, Сyril Сlarkе, and Philip Shеppard. !7hilе thеrе was nеvеr any formal struсturе' thе mеmЬеrs wеrе markеd Ьy a сonrmon appгoaсh to the study of gеnеtiс variatiоn in natural populirtions,and, in partiсular, Ьy a сommitmеnt to thе pеrvasivеrolе of natural sеlесtionas thе most important agеnt of еvolutionary сhangе. Kеttlеwеll was a giftеd nаturalist who lеft mеdiсal praсtiсе at thе agе of 41 to pursuе his Ьoyhood lovе of еntomology. Hе Ьеgan working full timе as a sеnioг rеsеаrсhеrin Е' B. Ford's nеwly foundеd suЬunit of gеnеtiсsat oxford in 1951' Kеttlеwеll is Ьеst known for his rеsеarсh on thе phеnomеnon of industrial mеlanism, whiсh rеfеrs to a rapid inсrеasе in thе frеquеnсy of rarе dаrk forms in mаny moth spесiеsin thе viсinity of mantrfaсturingсеntеrs as a сoпsеqцеnсе of thе first largе-sсalеair pollution assoсiatеdwith thе Industrial Rеvolution in Еngland аnd Continеntal Еuropе. Thе first and most famous ехamplе of this trеnd oссurrеd in thе pеppеrеd mot|7,Вistoп betulаriа' Thе dark tЪrm in this spесiеswas fiгst disсovеrеd nеar Manсhеstеr in 1848. .$Иithinthе spасе of only 50 yеars it Ьесamе so сommon that thе palе fоrm was loсally еxtinсt. (Tutt 1891 is thе сlassiс ninеtееnth-сеnturydisсussion of thе topiс.) Kеttlеwеll Ьесamе famous fог a sеriеs of fiеld ехpеrimеnts сonduсtеd in thе еarly 1950s doсumеnting thе rеason why thе dark forrn was Ьесoming mofе сomlnon. In pollutеd arеas, dагk сoloration protесtеd thе moths, rеsting on soot-darkеnеd trее trunks, against Ьird prеdation. In аn еlеgant fiеld еxpеrimеnt сonduсtеd in thе suп1mеrof 195З, Kешlеwеll rеlеasеdlargе nrrmЬеrsof markеd palе and dark moths into a pollutеd wood nеar Birmingham and attеmptеdto сapturе as many as possiЬlе ovеr thе nехt sеvеral nights. Thе logiс Ьеhind his invеstigationwas that, all things Ьеing еqual' thе rесapturе ratеs for thе two forms should Ье thе samе. If' on thе othеr hand, thе dark form was at an advirntagе'owing to its rеlativе inсonsptсtlousnеss'onе would ехpесt thе rесapturе rаtе for it to Ье highеr Ьесausе morе of thе dаrk form survivеd during thе intеrvаl Ьеtwееn rеlеasе and rесapture. And this is prесisеly what Kеttlеwеll found. Kеttlеwеll сonduсгеd а сompanion еxpеrimеnt in an unpollutеdwood in Dorsеt in thе summеr of 19S5 whеrе hе found thе rеvеrsе. In this wood hе was aЬ|еto rесapturе mсlrе of thе palе form thаn thе dark. Kеt. tlеwеll supplеmеntеd thеsе ехpеrimеnts with a film rесoгd doсumеnting that

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Kimurа whеn Ьirds wеrе givеn a сhoiсе, thеy passеd ovеr inсonspiсuous moths in favor of thе moth that was morе сonspiсuous in its Ьaсkground rеsting sitе. (Sее Kеttlеwеll 1955 and 1956 for thе original rеports and Kеttlеwe|\ 197З for a summation and ovеrall disсussion.) Whilе tехtЬooks oftеn portray Kеttlеwеll's invеstigations as unproЬlеmatiс' rеsеarсhers (inсluding Kеttlеwеll himsеlf) rесognizе that thе initial invеstigations involvеd numеrous assumptions thаt arе opеn гo quеsrion (е.g.,thе rеSting sitе of moths). This has lеd thosе сritiсal of еvolutionary thеory to сlaim that thе phеnomеnon is no longеr an еxamplе of natural sеlесtion, and furthеr that thеre is a сonspiraсy Ьy tехtbook writеrs to hidе this faсt. (Hoopеr 2002 js a .Wеlls sеnsationalistiс aссount of thе work Ьy a journalist and 2000 is a sеvеrе' rеligiously motivatеd сritiquе by a Ьiologist who is a followеr of thе Rеvеrеnd Sun Myung Moon, foundеr of thе Unifiсation Сhurсh.) At lеast еight studiеs dirесtly addrеss pеrсеivеd problеms in Kеttlеwеll's initial invеstigation.Thе studiеs havе indеpеndеntly сonfirmеd that Ьird prеdation is thе most important faсtor in thе sprеad of thе dark form. Pеrhaps thе most сonvinсing еvidеnсе that it is an ехamplе of naturаl sеlесtion' howеver, сomеs from thе prеdiсtеd rapid dесlinе of thе dark form sinсе thе introduсtion of ..Сlеan Air'' lеgislation in thе Unitеd Kingdom and еlsеwhеrе. (Majеrus 1998 givеs a full ovеrviеw of modеrn rеsеarсhand Rudgе 2002,2005 addrеssthе сlаims of frаud.) в|BLIoGRAPнY Hoopеr, J.2002. Оf Мoths апd Меn: Thе Untold Stсlrусlf Sсiепcеапd thе Pеppеrеd МofЙ. Nеw York: Norton. Kеttlеwеll,Н. B. D. 1955.Sеlесtionехpеrimеnts on industrialmеlanismir-rthе lеpidoptеra.Неrеditу 9: З23_342. 1956.Furthеrsеlесtionехpеrimеnts on industriаlmеlanismin thе lеpidoptеra.Ilеreditу 10: 287-301. 1973. Thе Еuolutiсlпof Меlапism,Oхford: Сlarеndon. Majеrus,M. Е. N. |998. Мelапism:Еuolutiсlпiп Aсtioп.Oхford:Oхford Univеrsity Prеss. Rudgе,D. !и. 2002. Сryptiс dеsignson thе pеppеrеdmoth. Iпtеrпаtioпаl lourпаl of Tropiсаl Biologу апd Сoпseruаtioп(Rеuistаdе Bklklgiа Tropiсаl).50,no. 1: 1-7. 2005. Did Kеttlеwеllсommit fraud? Rе-еxaminingthе еуidеnсе'Pиbliс Uпdеrstаndiпg сlfSсiепсе14, no. 3:249-268. Tutt, J. !и. 1891. Меlапism апd Мelапoсhrсlismiп British Lеpidсlptеrа.London: Swan Sonnеnsсhеin. .!Иеlis' J. 2ООО.lсoпs of Еuolutioп:Sсiепсеor Муth?.Washington,DС: Rеgnеry.

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Kimura, Мotoo (|924_Т994) Motoo Kimura is Ьеst known for thе idеa that most еvolution аt thе DNA lеvеl oссurs Ьy random proсеsses'rаthеr than Ьy Darwiniаn nаtural sеlесtion. Prior to this, еvolutionists had attriЬutеd еssеntiallyall of еvolution to natural sеlесtion. Kimura arguеd thаt for most еvolutionary сhangеs' сhanсе is morе important. Within a сеll, a сharасtеristiсnumЬеr of сhromosomеs сan Ье found (for еxamplе, 46 in humans). Еасh сhromosomе is a long, tightly сoilеd thrеad of

DNA. DNA сonsistsl sinе, guaninе, and thy of a fеw thousand Ьas quеnсе of Ьasеs in tha thе DNA has no knov A mutation is a pеrma to a T. If thе сhangе l еffесt on thе individua oЬsеrvaЬlе еffесt. If a l frеquеnсy in thе popuI

nеtiс drift. ln t968 Kimura put Ьulk of сhangеs in thе random drift. Kimura thе population and ulti rеsult of natural sеlес еssеnсеof Kimurа's idе ory of еvolution; Kimu сovеrеd indеpеndеntly most of thе suЬsеquе narily attriЬutеd to hin It oftеn happеns in t its own sakе' turns ou stantial Ьody of thеor was fortunatе that thе сеnturiеs latеr, Ьut wi atе studеnt, Kimura s d o m p r o с е s s е s ,s u с h inсrеasе in thе popula gеnеrations it would t individuals that woul Kimura l'vorkеd out t, сial, or dеlеtеrious.Su in gеologiсal timеs. It turns out thаt th€ for anothеr is simply с rеasonaЬly wеll know сan Ье сhесkеd agains sеquеnсеsof this disс wе know thе mutatiol tion. For studiеs of е сloсk, whiсh depеnds'

It is now gеnеrallyt mals and othеr vеrtеЬ is still сontrovеrsial, hо It is сlеar that in somе lесtion. Thе answеrsv

Kimurа ovеr inсonspiсuous moths in i r l i t s Ь a с k g г o u n dr е s t i n g s i t е . l rеpоrtsand Kеttlеwеl'|197З vеstigationsаs unproЬlеmatiс, ; n i z еt h а t t h е i n i г i a l i l l v е s t i g а )еnto Чtlеstion(е.B..thе rеsting tionary thеoгyto сlаim that thе гаl sеlесtion' and fr-rгthеrthat lе this faсt. (Hoopеr 2О02 is a Llistirnd Wеlls 2000 is a sеvеrе, o is a followеr of thе Rеvеrеnd lrurсh.)At lеast еiglrt studiеs di; initial invеstigаtion.Тhе stud_ еdаtion is thе most important ; thе most сonvinсing еvidеnсе зvеr' сomеs from thе prеdiсtеd ..СlеanAir'' lеgislatiоn сtion of s 1998 givеs a fr"rllovегviеw of s thе сlaims of fraud')

itor1,of Sсieпсеапd thе Pеppеrеd mеlаnisnrin thе r industrial 'ustrialmеlanismin thе : Сlагеndon. .с/ll,lo l .х f о r d :O х f о r d U n i v е r s i r y d пroth.Iпtеrпаtioпаl lourпаl of ' BiсllogiаТropiсаl)50, no. 1' 1_7. aminingtЬe eуldeлсе.Publiс Britisb Lеpi dopterа. I'onrJon: DС: Rеgnегy. li \rVashington, -D.W:R.

аt most еvolution at thе DNA 'n Ьy Darwinian nаtural sеlесd еssеntiallа yll of сvolution to it еvolutionaryсhangеs' сhanсе hromosomеsсаn Ье found (for i a long, tightly сoilеd thrеad of

D N A . D N A с o n s i s t s о f а s е q u е n с еo f f o u r k i n d s o f Ь a s е s ,а d е n i n е , с y t o sirrе,guаninе. аnd tlryпrinе,аЬЬrеviatеd A, С, G, and T' A gеnе is ir stretсh of a fеw thousand Ьasеs that is rеsponsiЬlе for а spесifiс funсtion; thе sеquеnсе of Ьasеs in thаt rеgion dеtеrminеs thе funсtion. Мost of thе rеst of thе DNA has no known funсtion and is oftеn rеfеrrеd to as ..junk DNA.'' A mutation is a pеrmanеntсhangе in thе DNA; for ехamplе, a С may сhangе to ;r T' If thе сhаngе oссurs within a Е]еnе'it will oftеn hаvе somе visiЬlе еffесt оn thе irrс.lividuаlinhеritirrgit. Сhangеs irr tlrе ..junk'' usuаlly havе nсl oЬsеrvaЬlееffесt. If a partiсular qеnе or other sеqltеnсеof DNA сhangеs its frеquеnсy in thе population Ьy rаlrdоm proсеssеs' this is сallеd random gеnеtiс drift. ]n 1968 Kimura put forth thе idеa-vеry daring at thе timе-that thе grеat Ьulk of сhаngеs in thе DNA arе pr-rгеlyгаndom, thе rеsult of mtltation :.rnd random drift. Kimura arguеd thаt whеthеr thе nеw mutation iIrсrеasеsin thе population and ultimatеly displасеsits prеdесеssorDNA is usually not thе rеsult of natural sеlесtion Ьut, muсh morе oftеn, simply сhanсе. This is thе еssеnсеof Kimura's idеa. This might Ье сallеd thе mutation-random drift thеoгy of еvolution; Kimura сallеd it гhе nеutral thеory' Tlrе samе idеa lvas disсovеrеd indеpеrrdеntlyЬy Jaсk King and Th
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KIn|Иrа Мotoo Kimurа was Ьorn in okаzaki, Japan,on NovеmЬеr 1З,7924.He showеd an early aptitudе for mathеmatiсs' Ьut his dееpеst intеrеst was Ьotany. Hе grеatly еnjoyеd a miсrosсopе givеn to hinr Ьy his fаthеr. I-Iеnеvеr lost his intегеst in flowеrs, and in his larеr lifе hе was a suссеssfulorсhid Ьrееdеr. Hе was in high sсhool during thе еarly days of .!7orld .War II' and in 1944 was admittеd to thе Kyoto lrnpеrial Univеrsity. Hе was not invoivеd in military sеrviсе, Ьut wartimе lifе in Japаn was hard for еvеryonе. Aftеr thе war' hе joinеd thе laЬоrаtoгy ot Japаn's prеmiеrе gеnеtiсist'Hitoshi Kihara. Кiharа rесognizеd Kimura's talеnts and pеrmittеd him to spеnd his timе studying thе litеraturе of mathепratiсalpopulation gеnеtiсs. With thе hеlp of Amеriсаn gеnеtiсists working for thе Atomiс Bomb Сasualty Сommission, Kimura Was aЬlе to oЬtain а sсholarship to study in thе Unitеd Statеs. Aftеr a yеar аt lowa Staсе Univеrsity, hе transfеrrеd to thе Univегsity of Wisсonsin and bесamе a studеnt of Jamеs F. Сrow. Hе had thе opportunity for daily сontaсt with Sеwall Wright, onе of thе foundеrs of mathеmаtiсal populаtion gеnеtiсs.Aftеr rесеivirrghis doсtoratе in 1956,he rеturnеd to Japan and for thе rеst of his lifе was еmployеd Ьy thе National lnstitutе of Gеnеtiсs in Mishima, Japan. Hе сontinuеd his сollaЬoration with Сrow, and еaсh took еvеry opportuniry to spеnd timе with thе othеr. Togеthеr thеy authоrеd a nurnЬеr of papеrs and a tеxtЬook. Kimura diеd of amyotrophiс lаtеral sсlеrоsis on NovеnrЬеr 13, 1994, on his 70tlr Ьirthdаy. Although Kimura is Ьеst known for thе nеutral thеory and thе attеndant mathеmatiсs, hе was аlso knowl-rfor аpplying diffusion modеls to othеr proЬlеms. Thеsе involvеd tlrе solution of partial diffеrеntial еquations, at whiсh hе was partiсularly adеpt. Не ссlnsidеrеd thе еffесts of random fluсtuattons in thе intеnsity of naturаl sеlесtion,whiсh саn lеad to proсеssеsthat mimiс random gеnеtiс drift. Hе dеvеloреd a modеl of migration Ьеtwееn сoloniеs, in whiсh migrants movе тo onе of thе nеighЬoгing сoloniеs. Altogеthеr, hе wrotе six Ьooks and ovеr 6.50 sсiеntifiс papеrs' At thе timе of his dеath hе was Japan's Ьеst-known gеnеtiсistаnd hе had Ьееn thе rесipiеnt of many intеrnаtionаl honors' вIвLIoGRAPHY Сrow, J. F. 1997. Мotoo Kimura. BiogrаphiсаlМеmoirs of Felloшso|-tbе Roуаl Soсiеtу
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Laсk, David Laml

David LarnЬеrt Laсk v studiеs of Galfpagos f thе wild. Born in Lo sсhool in thе Kеnt and prizеs for natr.rгallristo lеgе, СamЬridgе, in 19 tion in his formal stud Cambridgе ornitholoд sеrvations and сonсlus writtеn a dozеn papеr Саmbridgеshirе (I934 Laсk surprisеdfriеn liеving that fiеldwork aссеptеd a joЬ as Ьiolс Dеvon. Laсk was еnсo dеnts trap and Ьand rо makе oЬsеrvationson thе Ьasis for a four.1,е Supеrfiсially'Laсk's Llowеvеr' LaсkЪ writir hе aссеpted an obsеrv Ьееrr sееn on at lеаst s tесhniquе of Ьanding t viduals, and it allowеd behavior. Laсk Ьеlievе sсiеntifiс. Не latеr ad ( 1 9 5 0 ) ' a с o l l е с t i o no f this appгoaсh to a sing Julian Нuxlеy Ьесan Lасk visitеd thе Gal6p study finсhеs. As had r of prеdators and с
L N o v е m Ь е r1 3 , 1 9 2 4 . H e his dееpеst intеrеst was 'im Ьy his fathеr. Hе nеvеr е was a suссеssful orсhid ys of !7orld !Иar II, and in ty. Hе was not involvеd in rd for еvеryonе. Aftеr thе gеnеtiсist,Hitoshi Kihara. :d him to spеnd his timе l gеnеtiсs. or thе Atomiс BomЬ Сasuсholarship to study in thе , hе transfеrrеdto thе Uniэs F. Сrow. Hе had thе op_ , onе of thе foundеrs of ; his doсtoratе in 1956, hе еmployеdЬy thе National ruеd his сollaЬoration with j timе with thе othеr. Totехtbook. Kimura diеd of |94,on lris 70th Ьirthdаy. Ll thеory and thе аttеndant -rsionmodеls to othеr proЬrеntial еquations' at whiсh : с t so f r а n d o m f l u с t u a t i o n s .ad to proсеssеSthat mimiс n i g r a t i o nЬ е t w е е nс o l o n i е s . ng сoloniеs. Altogеthеr, hе At thе timе of his dеath hе эn thе rесipiеntof many in-

irs of FеIlош'sof thе Roуаl i,uolutiс-l п. СamЬrid gе: оlutioп:Random fiхation of ,8. ,аr Еuolutioп апtL thе Nеutrаl -I.F.С. )hiсagoPrеss.

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Laсk, David Lambеrt (1910_|973) David Lambеrt Laсk wаrsa British ornithologist irnd есologist famous foг his studiеsof Gаlipagos finсlrеs,оnе of thе kеy ехamplеs of nаturаl sеlесtionin thе wild. Born in London, Laсk Ьеgan Ьird-wаtсhing whilе in Ьoarding sсhool in thе Kеnt and Norfolk сountrysidе. Hе wаs addiсtеd, winning sсhool prizеs for natural history thrее сonsесutivе yеzrrs.Hе еntеrеd Мagdalеnе Сo1lеgе, СamЬridgе, in 7929,Ьt::.'likе Сharlеs Darwin' Laсk found littlе inspiration in his formal studiеs. Instеad, hе took to thе fiеld with mеmЬеrs of thе СamЬridgе ornithologiсal СluЬ. Laсk also Ьеgan puЬlishing systеmatiсoЬsегvationsand сonсlusions on bird Ьеhavior. By graduation in 1933, hе had wгittеп а dozеn papеrs' and thе сluЬ sponsorеd him to writе Tbе Birds of Саm bridgesh ir е (|9 З4|. Laсk surprisеd friеnds and family Ьy not pursuing an aсadеmiс сarееr. Bеliеving that fiеldwork was unpopular in СаnrЬridgе faсultiеs, Laсk instеad aссеptеda joЬ as Ьiology mastеr at Dartington Hall' a progrеssivеsсhool in Dеvоn. Laсk was еnсouragеdto usе thе fiеld as а tеaсhing spaсе. Hе had studеnts trap and Ьаnd roЬins in thе nеarЬy wсlods, and hе еnсouragеdthеm to makе obsеrvationson teгritory and Ьеhаvior. Tlrеse studеnt projесts Ьесamе thе Ьirsisfor а four-yеaг stlldy of roЬins. Supеrfiсially,Laсk's Тhe Lifе of the Robiп (|943| was a typiсal lifе history. Howеvеr' Laсk's writing hid а геvolution in rnеthod. Еmpiriсally mеtiсulous, hе aссеptеd an oЬsеrvation as rеal ..only whеrе thе aсtion сonсеrnеd has Ьееn sееn on at lеast six oссasions'' (Laсk I94з, 6). Hе also usеd thе nеw tесhniquе of Ьanding Ьirds. This pеrmittеd long-tеrm studiеs of known individuals, and it allowеd him to ask сomplеx quеstions aЬout lifе history and Ьеhavior.Laсk Ьеliеvеdthat suсh mеthods madе еthology morе rigorous and sсiеntifiс. Hе lаtеr аddеd to his studiеs of roЬins witЬ Robin Redbrеаst (1950),a сollесtion of rеlаtеd litеrаturе,musiс, and tolk сulturе. Hе rеpеatеd this approaсh to a singlе Ьird with Sшifts iп а Toшеr (1956). Juliаn Huхlеy Ьесamе a mеntor and pгomotеr. Undеr his еnсourаgеmеnt' Laсk visitеd thе Galipagos Islands (from DесеmЬеr 1938 to April 19З9) to study finсhеs. As had many Ьеforе him, Laсk fiгst supposеd that thе aЬsеnсе of prеdators and сompеtitors for food mеant that natural sеlесtion was ехtrеmеly wеаk on thе islands. This was rеinforсеd Ьy Amеriсan сollеaguеs with whom Lасk сorrsultеdon thе way homе to Еngland. At thе Califorrria Aсadеmy of Sсiеnсеs and thе Amегiсan Мusеum of Nаtural Нistorv, L:rсk 669

670 Lаck ..gеnеtiсdrift'' modеls prowas shown how his oЬsеrvations fit wеll into thе posеd in thе 1930s Ьy Sеwаll Wгight and fashionaЬlеin Amеriса. A tесhniсal monograph (Laсk 1945, writtеn in 194О) dеtailеd his сonсlusions drawn from this influеnсе. Lасk rеvеrsеd his viеws shortly aftеr rеturning to Еnglаnd and to Huxlеy's influеnсе. ..Unехpесtеdly, a rесonsidеrаtion of thе original matеrial lеd to а markеd сhangе in viеwpoint rеgarding сompеtition Ьеtwееn spесiеs and thе Ьеak diffеrеnсеs Ьеtwееn thе finсhеs'' (Laсk 1947' у1).|n Dаrш,iп's Fiпсhеs and many popular artiсlеs thеrеaftег, Lасk madе two points aЬout natural sеlесtion in Gal6pagos finсhеs. First, hе сonnесtеd finсh Ьеaks to diеt, arguing thаt thеy wеrе wеll adaptеd to spесifiс fееding stylеs: largе sееds, small sееds, insесts, and fruit (sее figurе). Natural sеlесtion within еaсh spесiеs rеinforсеd spесializatiоn and сrеatеd highly adaptеd forms. Sесond, Laсk foсusеd on сasеs whеrе sеvеral spесiеsoссupiеd idеntiсal есologiеs in thе samе loсation. In thеsе сasеs, ..Sinсе thе сhanсе of thеir Ьеhе said, natural sеlесtionwas еspесiallyintеnsе: is nеgligiЬlе, onе of thеm should еliminatе thе othеr ing еqually wеll adaptеd сomplеtеly'' (Lack 1947,62)' Оn small islands, Laсk found only onе spесiеs of ground finсh, suggеsting that сompеtition lеd onе spесiеs to dominatе and othеrs to loсal еxtinсtion. on islands whеrе two or morе spесiеswеrе found, Laсk rеаlizеd that thеsе spесiеs Wеге nеvеr found with ехaсtly thе samе есologiеs.Natural sеlесtionwаs сausing spесiеsto highlight thеir diffеrеnсеs, thеrеЬy rеduсing сompеtition. This сausеd divеrgеnсе, as diffеrеnt spесiеs

adaptеd to diffеrеnt hl vеrgеnсе) Laсk suggеs tanсе; thеy offеrеd a s wild. Inspirеd Ьy this (1944), and of thе сor Dаrшiп's Fiпсhеs п natural sеlесtion into whеn еvolutionists w ..artifiсial'' (laЬorato

prinсiplе of сompеtit .. Gausе in thе 19З0s. Еnglish еfforts to dе Е. B. Ford аnd rеinfor land snail, Сеpоеа, a Bistoп. Although thе RoЬеrt Bowman and sity оf сompеtition' i undеr way Ьy Pеtеr

сonсlusions. Io 1945, Laсk bес nithology' part of thе institutе had two goа data and ovеrsaw n.

Trust for Ornitholog; сal сommunity. Sесс ornithology. Laсk foс lation of population I сontrollеd populatior ators. Hе foсusеd tЬ took plaсе. Laсk's thе .. Еdwards and оthеr iп Birds (1'966).Hts 1 sizеd есologiсa1isola Not a strоng admi in thе dirесtor's сhait too narrowly. Laсk'r his wеaknеssеsas ar

Figurе 1. Ехamplеs of Darwin's finсhеs.Notе tЬе vеry diffеrеntЬеak shapеs, adaptеd to diffегеntfeeding stuffs-Ьig strong Ьеaks for hard nuts and thе likе, finе Ьеaksfor smаll sееdsand thе likе.

stцdеnts. Laсk сonvеrtеd to thе Angliсan Churсh Еuolutioпаrу Тhеor1 and еvolution сould Сhanсе proсеssеs's natural, not еvil. Еvс sеquеnt history. Thе сanсе of thе first сhс

Lасk hе ..gеnеtiсdrift'' modеls pro_ lnaЬlеin Amеriсa. A tесhniсal ltailеd his сonсlusions drawn rg to Еngland and to Huxlеy's . thе original matеrial lеd to a гition Ьеtwееnspесiеs and thе 947, vt). |п Dаrшiп's Fiпсbеs аdе two points aЬout natural arguing that thеy wеrе wеll small sееds,insесts' and fruit есiеs rеinforсеd spесiаlization :k foсusеdon сasеswhеrе sеvsamе loсation. In thеsе сasеs, ..Sinсеthе сhanсе of thеir Ье: rеm should еliminatе thе othеr ;' Laсk fоundonIy onе spесiеs ,d onе spесiеsto dominatе and lo or morе spесiеswеrе found, found with еxaсtly the samе s to highlight thеir diffеrеnсеs' ivегgеnсе.as diffегеnt spесiеs

е vеry diffеrеntЬеak shapеs, еаksfor hard nuts and thе likе,

adaptеd to diffеrеnt haЬitаts. Сhanging diеts was thе usual avеnuе for this divеrgеnсе' Laсk suggеstеd.In this intеrprеtation, Ьеaks took on spесial importanсе; thеy offеrеd a spесtaсular, nuanсеd ехamplе of natural sеlесtion in thе wild. Inspirеd Ьy this suссеss'Laсk madе similar studiеs of passеrine Ьirds (1944), and of thе сormorant and thе shag (1945). Dаrъuin's Fiпсbеs madе Laсk famous. Hе had transformеd a сasе against natural sеlесtion intо a prеmiеr еxamplе for it. His rеsеаrсh сamе at a timе ..natural'' rathеr than whеn еvolutionists wеrе сalling for morе studies of ..artifiсial'' (laЬoratory) еxamplеs of sеlесtion.It did thе samе for есology's prinсiplе of сompеtitivе еxсlusion' madе thеorеtiсally important Ьy G. F. ..Laсk's finсhеs''' many lаtеr сallеd thеm, also Ьoostеd as Gausе in thе 1930s. Еnglish еfforts to dеvеlop еvolutionary есolоgy, сhampionеd Ьy oxford's Е. B. Ford and rеinforсеd Ьy Arthur Сain and Philip Shеppard'sstudiеsof thе land snаil, Сеpаеа, and Bеrnaгd Kеttlеwеll's work on thе pеppеrеd moth' Biston, Although thе finсh сasе was сritiсizеd in thе 1950s' еspесially Ьy RoЬеrt Bowman and Daniеl SimЬеrloff, for ovеrstating thе ехtеnt and intеnsity of сompеtition, it nеvеr lost its allurе. By thе 1970s, long-tеrm studiеs undеr way Ьy Pеtеr and Rosеmary Grant сonfirmеd and ехtеndеd Laсk,s сonсlusions. In 1945, Laсk Ьесamе dirесtor of thе Еdward Grеy Institutе of Fiеld ornithology, part of the Dеpartment of Zoologiсal Fiеld Studiеs at Oxford. Thе institutе had two goals. First, it was a сеntеr for ехсhangе of ornithologiсal data аnd ovеrsaw nationаl сеnsus work in сollaЬoration with thе British Trust for Ornithology. This put Laсk in a сеntral position in thе ornithologiсal сommunity. Sесond' thе institutе sponsorеd original rеsеarсh in fiеld ornithology. Laсk foсusеd this rеsеarсhon population есology and thе rеgulation of population numЬеrs (Laсk 1954). Hе arguеd that only thrее faсtors сontrollеd population sizеs:disеasе,food availaЬility' and parasitеs or pred. ators. Hе foсusеd thе institutе's rеsеarсh on prесisеly how this rеgulation took plaсе. Laсk's thеoriеs wеге sеvеrеly сritiсizеd, еspесially by V. С. Wynnе..group Еdwards and othеr sеlесtionists.''Hе геpliеd wtth Pсlpulаtioп Stиdiеs iп Birds (1966). His final Ьook' Есologiсаl Isolаtiсlп iп Birds (1971'),еmphasizеd есologiсаl isolation as thе driving forсе of divеrsity. Not a strong administrator, Laсk Was morе сomfortаЬlе in thе fiеld than in thе dirесtor's сhair. Hе was сritiсizеd for fосusing thе institutе's attеntion too narrowly. Laсk's strеngths as аn ornithologist, howеvеr, far ехсееdеd his wеaknеssеsas an аdministrator. Hе was inspiring and mеntorеd many studеnts. .!Var II. Hе was сonfirmеd in Laсk сonvеrtеd to Сhristianity aftеr \World thе Angliсan Сhurсh in 1951, and hе rеmainеd dеvout throughout his lifе. In Еuolutionаrу Thеorу апd Сhristiап Beliеf (1957), Laсk arguеd thаt sсiеnсе and еvolution сould hеlp to ехplain mаny unrеsolvеd thеmеs in rеligion. Сhanсе proсеssеs' suсh as natural sеlесtion, сould Ье сrеativе. Dеath was natural' not еvil. Еvolution did not spеak to thе origin of lifе, only to its suЬ..Thе truе signifisеquеnt history. Thе BiЬlе and nаturе did not сontradiсt: сanсе of thе first сhaptеr of Gеnеsis is to assеrt that God madе thе univеrsе

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Lаmаrck and all in it, that Hе saw that it was good, and that Не plaсеd man in a spесial rеlationship to Himsеlf'' (Lack 1957,34). Laсk also sought to Ьеtterundеrstand arеas of gеnuinе сonfliсt. For instаnсе'many aspесtsof man's moral bеing sееmеdto him to Ье unехplainеd Ьy thеoriеsaЬout thе moral еvolution of animals. Laсk's ..Мy Lifе as an Amatеur ornithologist,, (797З| is an autoЬiography to 1,945, writtеn whеn hе Ьесamе dirесtor of thе Еdward Grеy Institutе. For ..amаtеur''to ..profеssional.'' him this markеd an important transition from !и. Н. Thorpе (1974) providеs thе kind of knowlеdgеaЬlе mеmorial only a сlosе friеnd сould pгoduсе. Laсk was awardеd thе Godman-Sаlvin Gold Меdal of thе British Ornithologists Union in 1958 and thе Darwin Mеdal of thе Royal Soсiеty iп 1972. BlвLloGRAPHY Grant, P., and R. Grant. \986. Есologу апd Еuсllutiсlпof Dаrшiп's Fiпсhеs. Pгinсеton,NJ: PrinсеtonUnivеrsityPrеss. Саmbridgе:СamЬridgеshirеBird СluЬ. Laсk' D. t934. The Birds of Саmbridgеshirе. -.7943. The Life of tbеRobiп. London:WithеrЬy. -. in passеrinеЬirds.Ibls 86: 1944.Есologiсalaspесtsof spесiеs-formation 260-286. -. A studyof variation.ОссаsioпаI 1945.Thе Gal6pagosfinсhеs(Gеospizinaе): Pаpеrsof thе Саliforпiа Асаdеmу of Sсiепсеs2T: 1-|59. -. 1947. Dапuin's Fiпсhes:Aп Еssау oп thе GепеrаlBiologiсаl Thеorу of Еuolиtion.СamЬridgе:СamЬridgеUnivеrsityPrеss. -. 1950.Robiп Redbreаsl.oхford: Oxford UnivеrsityPrеss. -. 1954. Thе Nаturаl Rеgulаtioпof Апimаl Numbеrs.oxford: СlаrеndonPrеss. -. 1956. St,uifts in а Тoъuеr.London: Mеthuеn. -Гhеorу -. |957. Еuсllutiсlпаrу апd СhristiапBеliеf:Тhе UпrеsoluеdСoп|liсt. London:Меthuеn. -, 1966. PopulаtionStudiesof Birds. Oxford: СlarеndonPrеss. -, 197I. Есologiсаl Isolаtiсlпiп Birds. London: Blaсkwеll. -' Ьy siх 1973.Мy lifе as аn amatеurornithologist[withapprесiatiоns Ibis 115: 421431. сollеaguеs]. H. С. G. Matthеwand Pеrrins,С. М.2004. Lасk' David LamЬеrt(1910_1973).In B. Harrison, eds',Охford Diсtioпаrу of Nаtioпаl Biogrаphу.oxford: Oxford UnivеrsityPrеss. Thorpе, \/.|7, 1974. David LamЬеrtLасk, 19|0-197з. BirlgrаphiсаlМеmсlirsof Felloшs of thе Roуаl Soсiеtуof Loпdoп 20z 271-29З. .Wеinеr, J. 1994. Thе Bеаk of the FiпсЬ:А Storусlf Еutllutioniп Оur Тimе.Nеvl -].С. York: Alfrеd Knopf.

Lamarсk, Jеan-Baptiste (|7 4 4_|829) Jеan-Baptistе Lamarсk Was thе first Ьiologist to sеt forth а Ьroad, сomprеhеnsivе thеory of organiс еvolution. Othеrs Ьеforе him had raisеd thе possiЬility that nеw organiс forms had appеarеd in thе сoursе of thе еarth's history, but Lamarсk was thе first to dеvеlop at lеngth thе idеa that all thе diffеrеnt forms of lifе on еarth had Ьееn produсеd suссеssivеly,Ьеginning with thе vеry simplеst forms and pгoсееding gradually to thе most сomplеx.

Lamarсk initially ml tЬe 177Оs with thе сirс in Paris. His саrееr сl was rесonstitutеd as th onе of thе profеssorsс was givеn instеad thе 1 mals.'' Hе soon сhara mals without vеrtеЬr initially to what hе kn сamе ovеr thе nехt twr zoology. Сlassifying thе invе thеm wеrе not Lamar onward, hе had spесu plеs of physiсs, сhеmi think aЬout thе histor rеlatеd to his studiеs с similaritiеs and diffеrе of his сontеmpоrariеs amplеs of unproduсtiv ..small faсts only with Ьеliеvеd) wеrе afraid t Lamarсk first sеt fo: troduсtory lесturе hе сlassin 1800. By 180 еarth, from thе simpl duсеd Ьy natural сaus mous еxpositions of h (Zoo\ogiсa| Philosop} sеvеn-volumе Work ol sаns uеrtёbres (Naturt Lamarсk sought to еvolutionаry thеorizir thе suссеssivеproduс thе diffеrеnt faсultiеs maintainеd that thе vс to bе' gеnеratеdspon sifiеd, hе сlaimеd, as t ,.po powеr of lifе'' or сomplеx'' (Lamarсk 1 partiсular сirсumstan nаtural aсtion of fluiс said, for thе ordеrly sr thеsе сausеs, in сontr thе mаin sсalе.It invo most famous: thе idеа

Lаmаrсk that Hе plaсеd man in a spеL,асkalso souglrt to Ьеttеr uтr' many аspесtsof man's moral riеsaЬout thе moral еvolutior-l t " ( 1 9 7 з )i s a n a ц t o Ь i o g r a p h y hе ЕdwzrrdGrеy Institutе. Foг ..аmatеur''to ..profеssional.'' owlеdgеablеmеrnoriаl оnly а [еd thе Godman-Salvin Gold 958 аnd thе Darwin Меdal of

toпof Dаrtuiп'sFinсhеs. ridgе:СаmЬridgеshirе Bird СluЬ. Ьy. in passеrinе Ьirds.Ibls 86: t studуof vаriаtion.Оссаsionаl , 1 :1 - l 5 9 . rcrаIBiсlk;giсаlTbеorу of )rеss. rеrsityPrеss. nbers.Охford:Сlаrеndоn Prеss. |'iеf: ТЬе Uпrеsolt',еd Сoп|liсt. lаrеndonPrеss. BIaсkwеll. ithapprесiations Ьy siх 973).|nH. с. G. Мatthеw and паl Biogrаphу.oхford: oxford 973.BiogrаphiсаlМemoirs of 1-29з. Еuolutiottiп our Tlиe. Nеw

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to sеt forth a broad, сomprе: f o r еh i m h a d г а i s е dt h е p o s s i l in tlrе сoursе of thе еarth's at lеngth thе idеa that all thе ' d u с е ds u с с е s s i v е I yЬ. е g i n n i n g 'гaduallyto thе most сomplеx.

Lamarсk initially madе his sсiеntifiсrеputаtion as a Ьotanist, intеraсtingin the 7770s with thе сirсlе оf Ьotanistsat thе Jaгdin du Roi (thе King's Gardеn) in Paris. His сarееr сhangеd dramatiсally io 779З whеn thе Jardin du Roi Was rесonstitutеd as thе National Мusеum of Natural Нistory. Hе was namеd onе of thе profеssoгs of thе nеw institution, Ьut not to a сhair of Ьotany. Hе Wаs givеn instеad thе profеssorshipof .,insесts,Worms' and miсrosсopiс animals.'' Hе soon сharaсtеrizеd this part of thе аnimal kingdom as thе ..animals without vеrtеЬraе''' Although his еxpеrtisе in this arеa was limitеd initially to what hе knеw from having Ьееn an avid сollесtor of shеlls, hе bесamе ovеr thе nехt two dесadеs thе world's lеading authority on invеrtеЬratе zoology. Сlassifying thе invеrtеЬratеs and dеvеloping a сoursе of instruсtion aЬout thеm wеrе not LaпrarсkЪ only сonсеrns in thе 1790s. Froпr tЬe Late 1770s onward, hе had spесulatеd Ьroadly aЬout what hе took to Ье thе Ьasiс prinсiplеs of physiсs, сhеmistry, and mеtеorology. In thе 1790s, hе also Ьеgan to think aЬout thе history of thе еarth. This nеw gеologiсal intеrеst was dirесtly rеlаtеd to his studiеs of shеlls and to thе еmегging proЬlеm of ехplaining thе .Whilе similaritiеs and diffеrеrrсеsЬеtwееn living and fossil shеll typеs. many of his сontеmporariеs wеrе inсlinеd to sее his Ьroad spесulativе еfforts as еxarnplеsof r.rnproсluсtivе..systеrrr_Ьuilding,'' hе сomplainеd of сritiсs who dеalt only with ..small faсts,'' who failеd to addrеss important issuеs, and who (hе Ьеliеvеd)wеге afraid thаt thеir rеputationswould Ье hrrrt Ьy his idеas. Lamarсk first sеt forth his rеvolutionary notion of spесiеs сhangе in an introduсtory lесtuге hе delivеrеd to thе studеtrts in his invеrtеЬratе zoology сlass in 1800. By 1802, hе was arguing that all thе diffеrеnt forms of lifе on еarth, from thе simplеst to thе most сomplеx, had Ьееn suссеssivеlyproduсеd Ьy rraturalсausеsopеratingovеr immеnsеpеriods of timе. Нis most 1Ъmous ехpositions of his idеas appеarеd in 1809 tr'hts Philosophie zoologique (Zoolоgiсаl Philosophy), and thеn in 1815 in the irrtroduсtion t
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Lаmаrck Lamarсk proposеd that animals wеrе induсеd to dеvеlop nеw haЬits whеn thеy wеrе сonfrontеd with сhanging or nеw еnvironmеnts. Сhangеs in haЬits inеvitaЬly lеd to сеrtain organs Ьеing usеd morе and othеr organs Ьеing usеd lеss' thеrеЬy strеngthеning thе formеr and wеakеning thе lattеr. Diffеrеnсеs thus aсquirеd wеrе passеd on to thе nеxt gеnеration, alЬеit too gradually to Ье apparеnt on a human timеsсalе. Ovеr grеat pеriods of timе' howеvеr, this rеsultеd in signifiсant organiс сhangе. Lamarсk was сonfidеnt that thе distinсtivе fеaturеs of suсh divеrsе сrеaturеs as giraffеs, molеs, storks, аnd snakеs сould Ье undеrstood as thе сumulativе rеsult of thе inhеritanсе of сharaсtеrs aсquirеd Ьесausе of long-maintainеd haЬits. Although thе Ьasiс idеa of ..thе inhеritanсе of aсquirеd сharaсtеrs'' Was not novеl with him, hе stands out as thе first sсiеntist to arguе at lеngth that thе opеration of this proсеss on a gеologiсal timеsсalесould produсе spесiеsсhangе. It was not until nеar thе еnd of thе ninеtееnth сеntury, wеll aftеr Charlеs Darwin had advanсеd his own thеory of еvolution, that thе idеa of thе inhеritanсе of aсquirеd сharaсtеristiсs, or ..usе.inhеritanсе,''сamе to Ье widеly rеgardеd as thе ..Lamarсkian'' еxplanation оf spесiеs сhangе in сontrast to Darwin's idеa of еvolution Ьy naturаl sеlесtion. This took plaсе еvеn though Lamarсk's idеas aЬout usе and disusе сonstitutеdiust onе part of his thеorizing and Darwin himsеlf strongly еndorsеd usе-inhеritаnсеas a mесhanism sесondingnatura1sеlесtionin thе еvolutionary proсеss.Thе first sеrious сhallеngе to thе idеa of usе-inhеritanсе сamе from Gеrman Ьiologist August .W.еismann in thе 1880s. Although thе idеa pеrsistеd into thе twеntiеth сеntury, it Ьесamе inсrеasingly disсrеditеd whеn it failеd to gain ехpеrimеntal сonfirmation and thе еmpiriсal еvidеnсе typiсally сitеd in its support was intеrprеtеdas Ьеing amеnaЬlе to othеr ехplanations. Lamarсk lеft his mark on sсiеnсе through his сontriЬutions to Ьotaniсal and еspесially zoologiсal systеmatiсs, his pionееring work in invеrtеЬratе palеontology, and his еvolutionary thеorizing. Although hе is primаrily rеmеmЬеrеd today for an idеa that Ьiologists nо longеr aссеpt-thе idеa of thе inhеritanсе of aсquirеd сharaсtеristiсs-hе nonеthеlеss stands out in thе history of Ьiology as thе first sсiеntist to sеt forth a сomprеhеnsivе thеory of organiс еvolution. в|BLIoGRAPHY .!И., Burkhardt' R. Jr. \995. Тhе Spirit of Sуstеm:Lаmаrсk апd Еuolutioпаrу Biologу. Nеw еd. СamЬridgе,x4A: Нarvard UnivеrsityPrеss. '1790_18з0. Сorsi, P. 1'988.Thе Аgе of Lаmаrсk: Еuolutit'lпаrуТhеoriеsiп Frапсе, J. МandеlЬaum'trans.Bеrkеlеy:Univеrsityof CaliforniаPrеss. Lamarсk, J.-B. 1809. Philсlsophiezсlologiquе,oи ехpositiсlпdеs сoпsidёrаtioпs rеlаtiuesd l'histoirenаturellеdes аnimаuх;Й lа diuersitёde lеur orgаnisаtioп et dеs faсultёsqu'ils еп obtieппеnt;аuх саusеsphуsiquesqui mаiпtiеппепteп еих Iа uiе еt doппепtliеu аих mouuеmепsqu'ils ехёсutепцепfiп'd сеllеsqиi produisепt,lеs uпеslе sепtimепt,еt lеs аиtrеsl'iпtсlligепсеdе сеttхqui cп soпt douёs.2vols.Pаris:Dеntu. prёsепtапtles \8\5-1822. Histoirе паturеllеdеs апimаuх sапsuеrtёbrеs, саrасtёresgёпёrаuхet pаrtiсuliеrsde сеs апimаих,lеиr distributioп,lеurs сlаssеs,lеursfаmillеs'lеursgепres,еt lа сitаtirlпdеspriпcipаlеsеspёсеsqui s'у

rаpportе,1t;prёсёdё essепtiеls dе l'апiпlа eпfiп, l'ехpllsitioп d D6tеrvillе.

Landе, Russеll (b

Russеl1Landе is widеl notypiс еvolution and in Jaсkson, Мississip Shrеvеport, Louisiana Thе son of a Ьiology swamps of Louisiana u Hе playеd Littlе Lеa sсhool, and hе Was a r Landе's intеrеstsin t at thе Univеrsity of С and thе physiсal sсiеnс approaсh in thе biolog rеading сluЬ organizе Thеir influеnсе еnсou versity of Сhiсago an< C. Lеwontin, еminеnt еvolutionaгy Ьiology. tin movеd to Нarvаrd As a graduatе stud for thе inhеritanсе of typiс еvolution. A сha Whilе lесturing on М quippеd, ..of сoursе polygеniс traits.',Thr in thе fiеlds of quantit doсtoral thеsis. Landе сontinuеd to a postdoсtoral studеn Madison. Hе also had from thе Univеrsity o1 \Х/right thе draft of hi not сarе for thе appr gеnеs that undеrlay tl that hе might havе bе Landе's dеvеlopmе joinеd thе faсulty at t Landе аppliеd his fra ual dimorphism and s typiс sеlесtion, phеno

Lаnde

to dеvеlopnеw haЬits whеn ronmеnts.Сhangеs in haЬits and othег organs Ьеing usеd lеnirrgthе lattеr. Diffегеnсеs ltion, аlЬеit too grаdually to 'еriods of timе, howеvеr, this l was сonfidеnt that thе disgiraffes, molеs, storks, and rеsult of thе inlrеritanсе of l haЬits. Although thе Ьasiс ' was not novеl with him' hе ;rh that thе оpеration of this spесiеsсhangе. ,h сеntury, wеll aftеr Сharlеs on, that thе idеa of thе inhеrtanсе,''сamе tO Ье widеly rеpесiеs сhangе in сontrast to This took plaсе еvеn though 'd i u s to n е p a г t o f h i s t h е o r i z - i n h е r i t а n с еa s a n r е с h a n i s m )roсеss.Thе first sеrious сhal,m Gеrman Ьiologist August sistеd into thе twеntiеth сеnit failеd to gain ехpеrimеntal l y с i t е d i n i t s s r r p p o r tw a s i n )ns. ris сontriЬutions to botaniсal эringwork in invегtеbratеpahouglrhе is primariiy rеmеmngеr aссеpt-thе idеa of thе .еthеlеssstands out in thе hisa сompгеhеnsivеthеory of or.

tmаrсhапd Еuсllutionаrу riversity Prеss. Гhеoriеs iп Frапсе,1790-18з0. ]aliforniаPrеss. рlo sition dеs сoпsi dёrаti oпs diuеrsitсdе lеur orgаltisаtioп mаintienl|епtеn ohуsiqиеs с1u,i епfiп,h сеllеsqui s ехёсt,ttепt; dе сеuх с1uiеп sont iпtеIligепсе prёseпtапtlеs sапsuertёbres, ruх,leш.distributioп'lеurs l dеspriпсipаlеsеs|lёсеsqui s'1'

rаpportепt; prёсёdёе d'ипе ilttrodисtioп offrаnt lа dёtеrпtiпаtioп dеs саrасtёres еssentiеlsdе l'апimаl, sа distiпсtklп du uёgёtаl et dеs аutrеs сorps паturеls; епfiп, l'ехpositirlп dеs prinсipеs fспdаmепtаtlх dе lа 7oologie.7 vols. Paris: _R.vИB. DёtеrviIlе.

Landе,Russеll(b. 1951) Russеll Lапdе is widеly rесognizеdas thе аrсhitесt of modеrn thеoriеsof phеnotypiс еvolution аnd as an innovator in сonsеrvation Ьiology. Born in 1951 in Jaсkson, Mississippi, Landе spеnt thе formativе yеars of his youth in Shrеvеport,Louisianа; Roswеll, Nеw Мехiсo; and Sеal Bеaсh, Сalifornia. Thе son of а Ьiology tеaсhеr аnd a pеtrolеum gеologist, hе ехplorеd thе swamps of Louisiana and Ьody surfеd on thе bеaсhеsof southеrn Сalifornia. Hе playеd Littlе Leaguе and Ьrеd hoodеd rats as a studеnt in grammar sсhool, and hе Was a memЬеr of math and honor soсiеtiеsin high sсhool. Landе's intеrеstsin есology wеге awakеnеd whеn hе was an undеrgraduatе at the Univеrsir1,оf Сalifornia at lrvinе. A tаlеntеd studеnt in mathеmatiсs and thе physiсal sсiеnсеs,Landе lookеd for оpportunitiеs to takе a quantitativе approirсh in thе Ьiologiсаl sсiеnсеs.That opportunity was providеd in a wееkly rеading сlub organizеd Ьy graduatе studеnts Tеd Саsе and Miсhaеl Gilpin. Тhеir influеnсе еllсourаgеd L:rndе to apply to graduatе sсhool аt thе Univеrsity of Сhiсago and to wоrk with profеssors Riсhard Lеvins and Riсhard С. Lеwontin, еminеnt praсtitionеrs of thе modеling appгoaсh in есology and еvolutionary Ьiology. Shortlу aftеr his arrival at Сhiсago, Lеvins and Lеwontin movеd to Hаrvard' Landе followеd suit. As a graduatе studеnt at Нaгvard, Landе foсusеd on dеvеloping thеory for thе inhеritanсе of quantitativе сharaсtеrs аnd using it to modеl phеnotypiс еvolution. A сhanсе rеmaгk Ьy Lеwontin hеlpеd sеt him on this сoursе. .Whilе lесturing on Меndеlisп-r,Lew
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Leаkeу еvolution. Еaсh of thеsе сontributions stands out Ьесausе novеl theorеtiсal formulations arе сombinеd with insightful litеraturе rеviеws and appliсations to aсtual data. Bеginning in thе 1980s, Landе's interеstsshiftеd to сonsеrvation Ьiology, as hе took thе lеad in сharaсtеrizing thе dеmographiс plight of thе Northеrn Spottеd owl by using a сomЬination of сlassiсal' modеrn, and original dеmographiс thеory. During this ongoing pеriod, Lаndе joinеd thе faсulty at thе Univеrsity of orеgon and latеr movеd to thе Univеrsity of Сalifornia at San Diеgo. Landе is сurrеntly a Royal Soсiеty Rеsеarсh Profеssor at Impеrial Сollеgе, London. B|вLIoGRAPHY Landе, R. 1976a.Thе maintеnanсеof gеnеtiсvariaЬilityЬy mutationin a polygеniс сharaсtеrwith linkеd|oсi.GепеtiсаlRеsеаrcb26:22I_2З4. 1976ь. Natural sеlесtionand random gеnеtiсdrift in phеnоtypiсеvolution. ЕuolutioпЗО:З14_3З4. 1977. Stattstlсaltеstsfor natural sеlесtionon quantitativесharaсtеrs' ЕuolutioпЗ7:442444. 1979.Quantitativеgеnеtiсanalysisof multivariаtе еvolution,appliеdto -cIд Ьrain:bodysizеallomеtry.Еuolиtion3З: 4О2-416.

Lеakеy,Louis SеymourBazett (t903-I972) Louis (pronounсеd Lеwis) S. B. Lеakеy, thе son of an Еnglish missionаry tо Kеnya in Еast Afriсa, Was Ьorn at а сhurсh mission station аt KaЬеtе, northwеst of NairoЬi in Kikuyu сountry. It was thе poliсy оf thе Сhurсh Мissionary Soсiеty to rotatе its missionariеs Ьaсk to Еngland еvеry fourth yеar so that thеy would not forgеt thеir Еnglish roots. Thе Lеakеys wеrе Ьrought Ьaсk in 19О4 aг.d stayеd for two yеars' rеturning to Kеnya in 1906. Thеir nехt Еnglish sojourn was Ьеtwееn 1910 and 191'3, at whiсh timе Louis bеgan formal sсhooling. In Ьеtwееn thosе timеs, thеy livеd аt thе missiоn station at Kabеtе. Thеrе young Louis joinеd a pееr group of Kikuyu boys and Ьесamе fluеnt in thеir languagе. Adoptеd into thе group' hе wаs formally initiatеd as a Kikuyu. Although hе oftеn said that hе thought of himsеlf as a Kikuyu, hе aсtеd and soundеd likе a good British сolonialist for thе rеst of his lifе. \World .VИarI intеrruptеd plans to Sеnd him to sсhool in Еngland. .sfhеn thе family rеturnеd thеrе in 1'919, Leakey was duly sеnt to a publiс sсhool in Dorsеt. Thе phеnomеnоn rеfеrrеdto in Еngland as а ..puЬliс'' sсhool is rеally a privatе institution. \Х/ith thе аid of a govеrnеss' hе was instruсtеd in mathеmatiсs' Latin, and Frеnсh. Although of a longtimе Еnglish family, Lеakеy's fathеr had Ьееn Ьorn in Franсе, so Frеnсh was oftеn spokеn at thе Lеakеy .!7hilе dinnеr taЬlе. Louis сould spеak thе languagе, hе еvidеntly did so with a pronounсеd Еnglish aссеnt' as did many of his сountrymеn. Lеakеy еntеrеd St. John's Сollеgе, CamЬridgе' as a frеshman in thе autцmn of 1922. He askеd if hе сould offеr Kikuyu as onе of thе two modеrn languagеs rеquirеd, and thе univеrsity turnеd to authoritiеs in London to ask

if thеrе werе qualifiеd C a m Ь r i d g е d u l y g a v еl thеy disсovеr that hе w thеn rеquеstеdro tгаin quеnt|y rесеivеdtop hс ors in his major fiеlds ..d C а m Ь r i d g ес a l l е dа ship from St. John.s Сс Lеakеy had Ьееn Ьaс thе summеr aftеr his sс pursuе work in thе arе tory. Thе first two Еa d o с u m е n t t h е Ь а s i sf o r tumn of l930, hе wa Ьasis of The Stonе Аg u n i v е r s i t i е st' h е r еw е r t o г a r е .T h е s o l е r е q u i p u Ь l i s h е dЬ o o k с o u n r His Afгiсanarсhаеo tools. Bесausе Lеakеy s i s t a n с еo f S i r A r t h u r thе Hunгеrian Мusеu was to havе a prоfoun dеspitе dесlaring his L yеars in a housе on thс (Kеith l 9 l5 ). Hе wаs human еvolution in Еr dеnсеfor humаn еvol I n l 9 З l , L е a k е yl е с visit to thе sitе that wo suЬsеquеnttimе: oldr stanсеof Lеakеy'sinге vai for morе than a th stonе tools dating Ьa< е v o l v е di n г o t г u еh u m i с a l f е v е гi n с a m p ' h i s thosе tools (M. Lеakе1 tition' but ir lасkеd tl walking bipеd. Сlеа Аustrаlop ith еcиs' pre forms гhat did еvolr.е a nеw gеnеriс аnd sр not stiсk' аlгhoughin first Еast Afriсan and tivеs геfеrrеdto аs hol had Ьееn dеvеlоpеdtс

Lеаkeу )ut Ьесаusеnovеl thеorеtiсal t u r еr е v i е w sа n d a p p l i с a t i o n s ftеd to сonsеrvation biology' raphiс plight of thе Northеrn :al, modеrn, and original dе, Landе joinеd tirе faсuity at l е U n i v е г s i t yo [ С a l i f o r n i a а t lеsеarсhPrоfеssorat Impеrial

ilitу by mutation in а pоlygеniс 6:22|_2З4. iс drift in phеnotypiс еvolution. n quaпtitativесharaсtеrs' virriаtееvоlution,аppliеd to

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.1e72) n of an Еnglish missionary to ision station at KaЬеtе, northpoliсy of thе Churсh N4issionЕngland еvеry fourth yеаr so s. Thе Lеakеys wеrе Ьrought ning to Kеnya in 1906. Thеir I |9\3, at whiсh timе Louis ; , t h е yI i v е da t t h е m i s s i o n s t a )еr group of Kikuyu boys and hе group, hе was foгmally iniat Ье thоught of hiпrself as a itish сolonialist for thе rеst of l sсhool in Еngland. Whеn thе шly sеnt to a publiс sсhool in ..puЬliс''sсhool is rеally d as а 'ss' hе was instruсtеd in mathryimе Еnglish farrrily, Lеakеy's ts oftеn spokеn at thе Lеakеy ;uagе,hе еvidеntly did so with lls сountrymеn. Jgе, as a frеshman in thе auшyllas ol1е of thе two modеrn o authoritiеsin London to ask

if thеге wеrе qualifiеd Kikuyu spеakеrsin Еngland. Tlrе answеr Was yеs' so Сambridgе duly gаvе Lеakеy thе permission hе had rеquеstеd.Onlу latег did thеy disсovеr that hе Was onе of only two Kikuyu spеakеrs known, so hе was thеn rеquеstеd to train thе pеrson who Ьесamе his own еxaminеr. I Iе suЬsеquеntly rесеivеd top honors in his languagе еxams. Hе also rесеivеd top honors in his majoг fiеlds of anthropology and arсhаеology' giving him what СamЬridgе сallеd a ..douЬlеfirst'' in 1926'This еarnеd him а rеsearсlrfеllor'i. ship from St. John's Сollеgе for tlrrее yеars' rеnеwеd again for thrее morе. Lеakеy had Ьееn Ьaсk to Еast Afriсa as part of a dinosaur-hunting group in thе summеr aftеr his sophomorе yеar, Ьut with thе fеllowship hе was aЬlе to pursuе work in thе :rrеaof his training and intеrеsts,namеly' Afriсan prеhistory' Thе first two Еast Afriсan arсhаеologiсal ехpеditions allowеd him to doсumеnt thе Ьasis for an arсhаеologiсalsеquеnсеof Еast A1riса. In thе autumn of 1930, hе was awardеd a PhD from СamЬridgе Univеrsity on thе Ьasis of Thе Stoпе Age Сulturеs of Keпуа Сoloпу (1931). Unlike Amеriсаn univеrsitiеs,thеrе wеrе no сoufsеs or еxams rеquirеd in ordеr to еaгn а doсtoгatе.Thе sole rеquiгеmеntwas аn aссеptaЬlеdoсtoral dissеrtаtion,аnd a publishеd Ьook соuntеd. His Afriсan arсhaеologiсalwork yiеldеd human skеlеtalmatеriаl аs wеll as tools. Bесausе Lеakеy was not trainеd in skеlеtal ilnalysis, hе souglrt thе assistanсеof Sir Arthur Kеith, a highly rеspесtеdanаtomist and thе сurator of thе Huntеrian Мusеum at thе Royal Collеgе of Surgеons in Londorr' Kеith was to havе a profound еffесt on Lеakеy's views on hurrrаnеvolution. Kеith, ..Darwinism'' dеspitе dесlarirrghis Ьеliеf in and spеnding nеarly thе lаst 25 yеars in a housе on thе Darwin еstatе'was in faсt pгofoundly anti-Darwinian (Kеith 1915). Hе was largеly thе rеason why many profеssional studеnts of human еvolution in Еngland and Amеriсa rеfusеd to aссеpt thе аvаilaЬlе еvid е n с еf o r h u m a n е v o ! u t i o n . In 193i' Lеakеy lеd his tlrird Еаst Afriсan arсh:rеologiсalехpеdition tllr e visit to thе sitе that would Ье idеntifiеd with Lеakеy's impaсt on thе fiеld for all suЬsеquеnt timе: olduvai Gorgе in what is now сallеd Tanzania. Thе suЬstanсе of Lеakеy's intеrnаtional rеputation was groundеd in his work at olduvai for morе than ir third of a сеntuгy. In thе first yеar, hе found quаntitiеs of stonе tools dadng Ьaсk to thе vеry еaгliеst madе Ьy tЬе anсеstorsof w,hat еvolvеd into trце humans. In July 1959, whilе Lor.riswаs suffеring from a tropiсal fеvеr in сamp' his wifе' Мary Lеakеy, found tlrе first fossil of а makеr of thosеtools (M. Lеakеy 1984).It h:rdan apе-sizеdЬrain and an еnormous dеntition, Ьut it laсkеd thе projесting сaninеs of a truе apе and it was an еrесtwalking bipеd. Сlеarly it wаs геlatеd to thosе rtrеmЬеrs of tlrе gеnus Austrаlopithесl,ts, prеviousiy known only frorn South Afriсil and inсluding forms that did еvolvе into thе genus Homo. As hе did so oftеn, Lеаkеy gаvе it a nеw gеnеriс and spесifiс name, Zinjапthropиs bсlisei' Thе gеnus namе did ,,Zinj.,, not stiсk' although informally it is still known as Not only was it thе first Еast Afriсan and thе most spесtaсulаr mеmЬеr of thе еarly hurnаn rеla. tivеs rеfеrrеd to as hominids, Ьut thе tесhniquеs of radioaсtivе isotopе irnalysis had Ьееn dеvеlopеd to thе ехtеl1tthаt it сould Ье givеn an aЬsolr.rtеdatе of ovеr

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Lеdеrbеrg 1.5 million yеars. Previously, thе Australopithесinеs known only from South Afriсir wеrе assumеd to Ье approximatеly half a million yеars old and muсh too гесеnt to havе playеd а r<>lе irr l.luman еvolution. Еvеn though Ztni was a sidеlirrе,llot oп thе pаth toward tгuе humans, its grеar аntiquity аnd primitivе hominid traits providеd sr.tЬstanсе for Charlеs Dаrwin's (1s71) suggеstionthat Afriсa was thе originаl loсаlе for thе еvolution of hr-rnr:rn form. Lеakеy took full advantagе of thе opportunity provid ed Ьу Zinj. Hе wrotе a sегiеsof tесhniсal as wеll as popular dеsсriptivе artiсlеs. Еvеn morе еffесtivе was his prеsеnсеon thе lесturе plаtform. A сharismatiс and сolorful puЬliс spеakеr' his frеquеnt intеrnirtionalappеaranсеsЬrought him еarningsthat supportеd furthеr fiеldwork, еspесially at Olduvai Gorgе аnd еlsеwhеrе in Еast Afriсаr.This also еnсour:rgесlothеrs to еnр.agеin thе sеarсh for еarlу honrinids and thеir tools еlsеrvhеrеin Еast Afriса. Hаrdly a yеar goеs Ьy now without furthеr disсovеriеs. Lеakеy also promotеd fiеldwork on living grеat apеs-сhimpanzееs and gorillas in Afriсa and orangutans in SouthеastAsia-Ьy a sеriеs of prot6g6s who havе grеаtly ехpandеd what wе know aЬout tЬе lifе and ways of humans' сlosеst nonhumаn rеlativеs. BIBLloGRAPнY Сolс' S. |975. Lеаkе1,.sLцсk:.l'hе l-ifе r'tfLouis Sе\'tlt
Lеdеrbеrg, Joshua(1925_200s) Joshua LеdеrЬеrgWas onе of thе lеading miсroЬiologistsand gеnеtiсistsof thе twеntiеth сеntury. His ехpеrimеntsехplorеd thе natuге of ftrndamеntalgеnе. tiс nrесhanismsin Ьасrеria:rnd thus slrеdlight on proсеssеsthat hеlpеd shаpе thе еvolution of thе rrrostaЬundаnt organisms on еilrth. For his сontriЬutions, lrе rесеivеd a NoЬеl Prizе irr 1958, at thе agе of З3. LеdеrЬеrg also advisеd poliсymakеrs on suсh mattеrs as еmеrging infесtious disеasеsand Ьiologiсal warfarе, and hе was awardеd thе Prеsidеntial Мedal of F.rееdomin 2006. LеdеrЬеrg madе thrее major сontriЬutions to undегstanding Ьaсtеrial gеnеtiсs' First, as a graduatе stuсlеntworking with Еdwаrd Tatum at Yalе Univеr_ sity, LеdеrЬеrg showеd that baсtеria сould rесomЬinе thеir gеnеsto produсе nеW gеnotypеs.This ехpеrimеnt dеmonstratеdthе ехistеnсеof a sехual pro_

сеss in Ьaсtеriа that r, that thе proсеssLеdеr or plasmid, that mеdia othеr' This pгосеss,kr еnаblеd sсiеntiststo rr somеs' in a mannеr lo Ьy Thomas Hunt Мor Sесond, working ш 'sИisсonsin, LеdеrЬеrg as vесtors to movе gе this virus-mеdiatеdp rolе irr faсilitating yеa Ьaсtегiаl gеnеtiсs. Third, LеdеrЬеrg : rеpliсa-platingехpеri rial mutations-in par oссurrеd prior to th mutations сould not rесtеd mannеr to thе t at гandoш, with sеlе nеtiс аdaptаtion. In o winian mесhanisms i Salvador Luria and tr sion, thе rеpliсa-plati it providеd a striking on a mastеr pеtri disl mutаnt dеsсеndantsi populаtion, using a v suЬjесt to sеlесtionfo from thе сorrеspond is
Lеdеrberg nеs known only from South million yеars old and muсh ion. Еvеn though Zin1 was a g r е а te n t i q u i t ya n d p г i m i t i v е rwin's(1871) suggеstionthat human form. providеd Ьу Ztn1. F{е wrotе vе artiсiеs. Еven morе еffесharismatiсand сolorful puЬеs brought him еarnings that v а i G o r g е a n d е l s е w h е r еi n gе in thе sеarсhfor еarly hoHaгdly a yеar goеs Ьy now геat apеs-сhimpanzееs and \sia-Ьy a sеriеs of protёgёs )ut thе lifе and ways of hu-

юur Bаzеtt Lеаkеу. Nеw York: l in Rеlаtitlп,o Sex. l,ondon: iаms аnd Nоrgatе. ца Ссloпу. Сambridgе: 1. Nеw York: Harсourt Brасе lphу. London: Wеidеnfеld and пilу апd tbе Quеst fсlr -С.L.B. 1Sсhustеr.

iologists and gеnеtiсists of thе ) naturе of fundamеntal gеnе,n proсеssеsthat hеlpеd shapе n е а r t h .F o r h i s с o n t r i Ь u t i o n s , lf 33. LеdеrЬеrgalso advisеd сtious disеasеsand Ьiologiсal Iеdalof Frееdom tn2О06' undеrstandingЬaсtеrial gеnе_ idward Tatum at Yalе UnivеrlmЬinе thеir gеnеs to produсе thе еxistеnсеоf a sехual pro-

сеss in Ьaсtеria that was not prеviously known. SuЬsеquеnt rеsеarсh showеd that thе proсеss LеdеrЬеrg disсovеrеd involvеs an ехtraсhromosomal еlеmеnt, or plasmid' that mеdiatеs thе movеmеnt of Ьaсtеrial gеnеs from onе сеll to anothеr. This proсеss' known as сonjugation, also providеd a powеrful tool that еnaЬlеd sсiеntists to map thе physiсal pоsition of Ьaсtеrial gеnеs on сhromo. somеs' in a mannеr logiсally similar to thе mapping studiеs pioneеrеd еarliеr Ьy Thomas Hunt N4organ and сollеaguеs with fruit fliеs. Sесond, working with his studеnt' Norton Zinder, at thе Univеrsity of .Wisсonsin, LеdеrЬеrg disсovеrеd that virusеs that infесt Ьaсtеria сould sеrvе as vесtors to movе gеnеtiс matеrial from onе strain to anothеr. Thеy сallеd this virus-mеdiatеd proсеss transduсtion and it, too, playеd an important rolе in faсilitating yеars of inсrеasingly dеtailеd and sophistiсatеdstudiеs of Ьaсtеrialgеnеtiсs. Third, LеdеrЬеrg and his first wifе, Еsthеr LеdеrЬеrg' dеvеlopеd thе rеpliсa-platingехpеrimеnt.This еlеgantехpеrimеnt dеmonstratеdthat Ьaсtеrial mutations-in partiсular, thosе that сonfеr rеsistanсеto viral infесtionsoссurrеd prior to thе Ьaсtеria Ьеing еxposеd to virusеs. Therеforе' thе mutations сould not havе Ьееn сausеd Ьy thе Ьaсtеria rеsponding in a dirесtеd mannеr to thе sеlесtivе agеnt. This work showеd that mutations arosе at random, with sеlесtion providing thе dirесtional forсе rеsponsiЬlе for gеnеtiс adaptation. In othеr words, Ьaсtеria arе suЬjесt to thе Samе basiс Dar.sИhilе an еarliеr еxpеrimеnt by winian mесhanisms as highеr organisms. Salvador Luria and Мaх DеlЬriiсk (1943) had supportеd thе samе сonсlusion, thе rеpliсa-plating еxpеrimеnt sеttlеd thе issuе еvеn for skеptiсs Ьесausе it providеd a striking visual dеmonstration. That is' rarе mutants that arosе on a mastеr pеtri dish, whiсh wеnt undеtесtеd aЬsеnt any sеlесtion, yiеldеd mutant dеsсеndants in thе samе rеlаtivе loсations following transfеr of thе population' using a vеlvеt pad, to sеvеral rеpliсa platеs whеrе Ьaсtеria wеrе suЬjесt to sеlесtion for rеsistanсе to viral infесtion. In faсt' Ьy sсrееning сеlls from thе сorrеsponding loсation on thе mastеr platе, thе LеdеrЬеrgs сould isolatе mutations without dirесtly еxposing thе baсtеria to thе sеlесtivе сonditions that favorеd thе mutant phеnotypе. At thе timе that LеdеrЬеrg and his сollеaguеspеrformеd thеsе pionееring ехpеrimеnts, littlе was known aЬout Ьaсtеrial еvolution. For thе nехt fеW dесadеs, thе fiеld of miсroЬiology mostly pursuеd gеnеtiс and molесular approaсhеs to undеrstanding сеllular strrrсturе and funсtion, paying littlе attеntion to еvolution. Howеvеr, thе past fеw dесadеs havе sееn inсrеasing work on miсroЬial еvolution, whiсh has followеd sеvеral approaсhеs and impеrativеs. First, thе fiеld of molесular еvolution rеvеalеd thе rеlationships of Ьaсtеrial spесiеs to onе anothеr and to othеr organisms, inсluding thе disсovеry Ьy Сarl \Woеsеof thе Arсhаеa' a group of singlе-сеllеd' non-nuсlеatеd оrganisms that arе distinсt in many rеspесtsfrom truе Ьaсtеria.Thе approaсh of molесular еvolution has also Ьееn usеd to ехaminе thе еxtеnt of gеnе ех. сhangе within and among Ьaсtеrial spесiеs,thus ехtеnding our undеrstanding of thе gеnеtiс mесhanisms disсovеrеd Ьy LеdеrЬеrg in thе laboratory to thеir

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Lеssonsin СomparativеAnatomy importanсе in naturе. Sесond, owing to thеir rapid gеnеrations and othеr traсtablе fеaturеs, Ьaсtеria arе now oftеn usеd in ехpеrimеnts that sееk to undеrstand thе dynamiсs of phеnotypiс and gеnomiс еvolution as wеll as to tеst partiсular hypothеsеs aЬout еvolutionary phеnomеna. Finally, thеrе is growing attеntion to thе rolе that еvоlution plays in thе еmеrgеnсе of nеw infесtious disеasеs,inсluding thе aсquisition of virulеnсе faсtors that allow pathogеns to infесt thеir hosts as wеll as thе sprеad of antiЬiotiс rеsistanсе. Thе mесhanisms of gеnеtiс ехсhangе disсovеrеd Ьy LеdеrЬеrg havе Ьееn found to Ье vеry important in thе еmеrgеnсе of many nеw Ьaсtеrial pathogеns. вIвLIoGRAPHY Еlеna, S. F., and R. Е. Lеnski. 2003. Еvolution еxpеrimеntswith miсroorganisms: Thе dynamiсsand gеnеtiсbasеsof adaptation.Nаtиre ReuiеtusGeпеtiсs4з 457469. Lеdеrbеrg, disеasеas an еvolutionaryparadigm.Еmеrgmg I. 1997.Infесtious IпfеctioиsDisеаsеsЗ: 417423. Lеdеrbеrg, J., and Е. M. LеdеrЬеrg.|952. Rеpliсaplatingand indirесtsеlесtionof bасtеrialmutants.Jourпаl сlf Bасtеriologу63: З99406. Luria, S. Е.' and M. DеlЬriiсk. 1943. Мutations of Ьaсtеriafrom virus sеnsitivityto virus rеsistance.Geпеtiсs28 491-51\. National LiЬrary of Меdiсinе.N.d. Profiiеsin sсiеnсе.Thе JoshuaLеdеrЬеrgpapеrs. http://profi lеs.nlm.nih.gov/BB/. Tatum, Е. L., and J. LеdеrЬеrg.|947. GenеrесоmЬinationin thе Ьасtеrium Еsсhеriсhiасoli. Jourпаl of Bасteriologу5З 673-684. .Woеsе, с. R., O. Kandlеr,and М. L. !Иhееlis.1990.Towardsa naturalsystеmof organisms:Proposalfor thе domainsArсhаеa,Bасtеria,and Еuсarya. Proсееdiпgsof thе NаtklпаI Aсаdеmу of SсiеnсеsUSА 87 4576-4579. Ztndеr, N. D., and J. LеdеrЬеrg.1952. Gеnеtiсехсhangеiл Sаlmoпеllа.lourпаl of Bасteriologу 64: 67 9-699.

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Lessons iп Compаrаtiue Anаtomу (GеorgеsСuviеr) In his еvеr-Ьusylifе, thе yеars 1795 to 1802 wеrе partiсularly hесtiс onеs for Gеorgеs Cuviеr. on July 2, 1,795,thе profеssors' assеmЬly at thе Mus6um national d'histoirе naturеllе approvеd his nomination аs assistant to JеanСlaudе N4еrtrud, thе anatomy profеssoг, and hе startеd in еarnеst tO arrangе thе сomparativе anatomy сollесtion. Hе gavе lесturеs at thе museum and rеad sсiеntifiс papегs to a variеty of soсiеtiеs (thе Soсiёt6 Philomatiquе and thе Natural Нistory Soсiеty in partiсular) and at thе Institut dе Franсе (institutеd in 7795 to rеplaсе thе old Aсadеmiеs, inсluding thе Aсad6miе frangais and thе Aсad6miе dеs sсiеnсеs).Сuviеr took full advantagеof thе musеum liЬrary that Ьеnеfitеd, as did thе musеum itsеlf, from important additions ас. q u i r е d f r o m t h o s е Е u г o p е а nс o u n t r i е sс o n q u е r е dЬ y t h е F r е n с h a r m i е s . During 1798 and 1799, assistеd Ьy Andr6.Mariе-Constant Dum6ril (1774*1860), Сuviеr workеd on thе nоtеs Dum6ril had takеn at his lесturеs in thе prеvious four yеars. Thе first two volumеS of tЬ'eLесoпs d'апаtomie

сompаrёе (Lеssoпs il thrее morе volumеs' с p u Ь l i s h е dЬ y 1 8 0 5 . V thе organs of sеnsatio and thе organs for prо and sесrеtion. Сuviеr ..thе есonoп tions on prеfaсе to thе work, l Ьеing dеstroyеd''(Сuv

Сuviеr quotеd Immar ..саusе'' of еvеry sing

organism in itsеlf. Dr notably Antoinе-Laur tion of parts" (1789\ a n a t o m y ( 1 8 0 5 ) 'С u v tion, nutrition, vision ..laws of сoеxistеnсе' tion of onе organ or р thе wholе organism a funсtions of intеrnal divisions within thе l tivе anatomy provеd с

sifiсation. Сuviеr plaсеd stron tion Ьy insisting that isms. Lifе, hе agrееd propеrty to tеmpora agеnts. Hе did not dt timе unvеil thе intim ..animal maсhinе.'' Fi tеnсе of a сhain of Ье isms to man. Gradua intеrnal organs, and twееn еaсh of thе ma anatomy was disсovе

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C o l е m a nW , . 1 9 6 4 .G е Сambridgе,MA: Н Сuviеr,G. \80О.Leqoп Baudouin. 18О5.Lеgoпsd Baudouin. J u s s i е uA, . L . d е .1 7 8 9 O u t r a m ,D . 1 ' 9 8 4 .G е с rеuolutioпаrуFrаn

Lеssonsin СomparativеAnatomy apid gеnеrationsand othеr in ехpегimеntsthаt sееk to lnomiс еvolution as wеll as / phеnomеna.Finally, thеrе plаys in thе еmеrgеnсе of on of virulеnсе faсtors that thе sprеaсо i f antiЬiotiс гее disсоvеrеd Ьy LеdеrЬеrg nеrgеnсеof many nеw Ьaс.

mеrrtswith miсrоorgаnisms: ,аttlrе Rеuieшs Gепеtiсs 4: rry paradigm. Еmеrging Ltingand indirесt sеlесtion of 9406. сtеria from virus sеnsitivity to . Thе Jоshua LеdеrЬеrg pаpеrs. ation in thе baсtеrium -684. fowаrds а nаturаl s,vstеmof rсtеria'and Еuсaryа. s USА 87: 4576-4579. 'ngein SаImoпеllа.lourпаl of

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)orgеsСuviеr) .е partiсularly hесtiс onеs for rs' assеmЬlyat thе Мusёum ination аs assistant to Jеanstartеdin еarnеstto arrangе lесturеsat thе musеum and hе Soсi6t6Philomatiquе and г thе Institutdе Franсе (insti. ' u d i п gt h е A с a d ё m i еf г l r n g а i s advаntagеof thе musеum ii.rom important additions aсd Ьy thе Frеnсh arnriеs. |r6-Мariе-Сonstant Dumёril r6rilhad takеn at his lесturеs еs of thе Lеqons d.оltаtomie

с()|пpLlrёе(Lessons iп Сompаrаtiue Апаtomy/ appеarеd in Мarсh 1800; thrее morе voluпtеs, еditеd Ьy Gеorgеs Louis Duvеrnoу (1777_1'85.5), wеrе puЬlishеd Ьy 1805. Volumе 1 dеalt with thе organs of movеmеnt; volumе 2' thе organs of sеnsation;volumеs 3 and 4, digеstion, сirсulation, rеspirarion, and thе organs for produсing sounds;and volumе 5, thе organs of gеnеration and sесrеtion.Сuviеr dеvotеd his first lесturе to mеthodologiсal сonsidеratiсlns on ..thе есonomy of lifе.'' Living organisms, hе had dесlarеd in thе prеfасе to thе work, arе ..maсhinеs. . . that сannot Ье takеn apart without Ьеingdеstroyеd'' (Cuviеr 1800, 1: V). Lесturе 1 ехpandеd upon this сonсеpt. Сuviеr quotеd Immanuеl Kant to statе that thе raison d'ёtrе, thе intimatе ..с:lusе'' of еvеry sirrglеliving part Or organ' was in thе ..wholе,'' that is, thе organism in itsеlf. Drawing upon prеvious Ьotaniсаl and anatomiсal work, notaЬly Antoinе-Lаurеnt dе Jussiеu'sсonсеpt of ..сorrеlationand sr-rЬordinatiоn of parts'' (L789) and Fеliх Viсq-d'Azyr's appliсation of thе prinсiplе to anatomy (1805)' Сuviеr showеd tlrat systеms of organs (digеstion,loсomotion, nutrition, vision' еtс.) arе in еvеry animal сlass rеlatеd to еaсh othеr Ьy ..lаws of сoехistеnсе''(Cuviеr 1800, 1: 57). Thus thе prеsеnсеand сonfigurati
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Leшontiп Rudwiсk, N{. 1997. Gеorges Сuuier, Fossil Bonеs апd Gеologiсаl Саtаstrophеs: Nеlu Trапslаtioпs апd Iпtеrpretаtiсlпs of thе Primаrу Ъxrs. Chiсago: Univеrsity of Сhiсago Prеss. Viсq-d'Azyr, F. |794 [1805]. Оеuurеs reсuеilliеs еt publiёes аueс dеs пotеs еt u|1 discours sur sа uiе еt sеs ouurаgеs |)аr М. Jасquеs L. Мorеаu dе lа Sаrthе. 6 -P.С. vols. Paris: Baudouin.

Lеwontin, Riсhard (ь. 1929) Riсhard Lеwontin has provеd to Ье еvеry Ьit as influеntial in population gеnеtiсs as his mеntor, Thеodosius DoЬzhansky. Likе DoЬzhansky' Lеwontin is wеll known for artiсulating a vеry dеfinitе pеrspесtivеof thе fiеld and thе most important proЬlеms to Ье solvеd-inсluding, likе DoЬzhansky' an еspесially pozz|ing..paradox.'' Likе DoЬzhansky, Lеwontin is wеll known for a highly original approасh to mеasuring variation at thе gеnеtiс lеvеl and for his own viеws of how Ьеst to ехplain that vаriation. Likе DoЬzhansky, Lеwontin twеakеd molесular Ьiologists for suggеstingthat mоlесulаr proсеssеsWеrе morе fundamеntal than thе еvolutionary proсеssеsthat aсtually gavе risе to thеm. Likе DoЬzhansky' Lеwontin has Ьееn dееply сonсеrnеd with thе Ьroadеr moral and politiсal signifiсanсе of gеnеtiсs and еvolution. ary biology. And, likе his tеaсhеr, hе has mеntorеd sсorеs of graduatе and postdoсtoral studеnts. But thеsе arе similaritiеs at a vеry high lеvеl of gеnеrality. othеrwisе, thеsе two influеntial population gеnеtiсistsarе vеry diffеrеnt! Along with DoЬzhansky' Еrnst Мayr, Gеorgе Simpson, and othеr еvolutionary Ьiologists' Lеwontin grееtеdthе fanfarе surrounding thе advеnt of molесular gеnеtiсs in thе 1960s with a сaцtionary rеmindеr to kееp in mind thе distinсtion Ьеtwееn еffiсiеnt and final сausе in Ьiology. Thе molесular сonfigurations of living organisms arе thе еffiсiеnt сausеs of Ьiologiсal phеnomеna Ьut not thеir final сausеs. That is, еxсеpt in a trival sеnsе' thе laws of gеnеtiсs arе not thе rеsult of thе struсturе of DNA, Ьut rathеr DNA has bееn сhosеn Ьy natural sеlесtionfrom among an immеnsе variеty of molесulеs prесisеly Ьесausе it fits thе rеquirеmеnts of an еvolvеd gеnеtiс systеm. DNA is only thе taсtiс adoptеd in thе сoursе of working out an еvolutionary stratеgy.That is why somе orgаnisms саn gеt on without it. (Lеwontin 1964, 566| But hе saw сonsidеraЬlеpromisе in thе nеw fiеld and was at thе vanguard of applying molесular gеnеtiс tесhniquеs to еvolutionary issuеs. In pаrtiсular, hе hеlpеd to pionееr thе usе of gеl еlесtrophorеsis to doсumеnt variation сlosе to thе gеnеtiс lеvеl-namеly, at thе lеvеl of amino aсid diffеrеnсеs rn protеins (duе to nuсlеotidе diffеrеnсеs in thе gеnеs that сodе for thosе protеins).In so doing, hе hеlpеd еstaЬlishthе fiеld of molесulaг population gеnеtiсs. His studеnt, Martin Krеitman, WaS thе first population gеnеtiсist to study variation dirесtly at thе DNA nuсlеotidе lеvеl, using morе rесеnt DNA sеquеnсingtесhniquеs.

Thе findings of Lе HuЬЬy, suggеstеd-gl еvеry gеnе loсus is po (HubЬy and Lеwontil This might sееm to Ь viеw of еvolution (i.е.

ural populations, mai ..сlas and against thе (i.е., that natural sеl ' within populations). thе rеsults wеrе parad Тhеrе was just too sресtivе' Lеwontin ar1 Kimura and Jamеs Сг a hеtеrozygotе сross ( periority at a partiсul rior homozygotеs and of thе population. Tht supеrior' thе grеatеr population, until thе I Morеovеr, Lеwontil Ьеttеr sеnsеof doсum variation'' thаt thеrе tion, no mattеr whеth thе Ьalanсе thеoristsl proposеd Ьy thе сlass еxplainеd in tеrms of tion, a position that L What is/was to Ье d tial tехt, Тhe Gепetiс suсh a riсh thеorеtiса сopе with thе Ьody oJ ary insight that in a flr tivity did for thе сont thе proЬlеm morе pеr еnсе? I Ьеliеvеit is thс onе rеason for thе not ..еmpiriсally suffi< bе mеasurеd dirесtly, twееn altеrnativе сat еpistеmologiсal сonсс infamous-for pеrsist Ьiologists сan possib know. His сritiquеs o drеls of Sаn Мarсo an Gould) and gеnеtiс d

I'еluoпtiп d G есllogicаl Саtаstrop h es : m а r у Т е х t s .С h i с a g о : U n i v е r s i t y 'ubliёеs аuес des пotas еt Im s L. Мorеаu dе lа Sаrthе. 6

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; influеntialin population gеL i k е D o Ь z h a n s k y ,L е w o n t i n эrspесtivеof thе fiеld and thе ling, likе DoЬzhansky' an еs., Lеwontin is wеll known for ltion at thе gеnеtiс lеvеl and variation. Likе DoЬzhansky, lggеstingthat molесular proionary proсеssеsthat aсtua1ly n hаs Ьееn dееply сonсеrnеd rсе of gеnеtiсsand еvolutionttorеdsсorеs of graduatе and itiеs at а vегy high lеvеl of эpulation gеnеtiсistsarе vеry Simpson,and othеr еvolution_ oundingthе advеnt of moiесundеr to kееp irr mind thе : in Ьiology. Thе molесullrг ffiсiеntсausеs of Ьiologiсal is, ехсеpt in a trival sеnsе, truсturе of DNA, Ьut rathеr rom аmong an immеnsе val rеquirеmеntsof аn еvolvеd :еdin thе сoursе of working somе organlsms сan get on

:ld and Was at thе vanguard of 'utionaryissuеs' In partiсtrlar' t o r с s i st o d o с u m е n t v а r i а t i o n l o f а m i n o a с i d d i f f е r е n с е si n gеnеsthat сodе for thosе proof molесularpopulation gеnе. f i r s t p o p u I a r i o ng е n е r i с i s гt o lеvеl,using morе rесеnt DNA

Thе findings of Lеwontirr and his еarly сollaЬorator in this work, Jaсk HuЬЬy, suggеstеd-givеn thе inhеrеnt Ьiasеs of tlrеir mеthods-thаt nс.агly еvеry gеnе loсus is polymorplriс, and that a third of all loсi arе hеtеrozygous (НuЬЬy and Lеwontin 1966; Lеwontin and Hr"rЬЬy|96Q Lеwс>ntin|974). This might sееm to bе strong еvidеnсе in favor of DoЬzhansky's ..Ьalanсе'' viеw of еvolution (i.е.,that thеrе is сonsidеraЬlеgеnеtiсvariation within natural populations' maintainеd largеly Ьy sеlесtion irr fаvor of hеtеrozygotеs) and against thе ..сlassiсal''position of DoЬzhansky's arсhrivаl, Н. J. Мullеr (i.е., that natural sеlесtion in favor of optimal gеnеs еliminatеs vаri:rtion within populations). To his tеaсhеr'sсlrilgrin, Lеwontin arguеd instеad that thе rеsultswеrе paradoxiсal' and not аt аll еаsy to ехplain. Thеrе was illst too muсh variation to makе sеnsе from thе Ьalanсе pеrspесtivе'Lеwontin arguеd, сiting similar сonsidеrаtionsproposеd Ьy Мotoo Kimura and Jamеs Сrow' Onе major proЬlеm is tlrat hаlf of tЬе offspring of a hеtеrozygotе сross (АаxАа) arе hornоzygotеs (АА, аа) . Heterozygotе supеriority at a paгtiсular gеnе loсus thus еntails thе prоduсtion of many infеrior homozygotеs and a сorrеsponding dесrеasеin thе rеproduсtivе сapaсtty of thе pоpulаtion. Thе grеatеr thе numЬеr of loсi аt whiсh hеtеrozygotеsaге srrpеrior' thе grеatеr thе damagе donе to thе rеproduсtivе сapaсity of thе population, until thе population would bе quitе unaЬlе to pеrpеtuatеitsеlf. Мorеovеr, Lеwontin arguеd, no altеггrativеto tl.lеЬalanсе viеw mаkеs any Ьеttеr sеnsеof doсumеntеd pattеrns of gеnеtiс variation. It is a ..paradoх of variation'' that thеrе is too muсh to Ье ехplainеd in tеrms оf natural sеlесtion, гlo mattеr whеthеr it is а variation-maintainingsort of sеlесtionsuсh as thе Ьalanсе thеorists had proposеd, or a variation-rеduсingsoгt suсh as that proposеd Ьy thе сlassiсal thеorists.Tlrеrе was also too muсh variation to Ье ехplainеd in tеrms of thе sеlесtivе insignifiсanсе or nеutrality of thе vаriation' a position that Lеwontin duЬЬеd ..nеo-сlаssiсa1.'' .Whаt is/was to Ье dorrе?or as Lеwontin pоsеd thе quеstion in lris influеrrtial tеxt, Thе Gепetiс Bаsis of Еuolutiсlnаrу Сbапge (7974,267),*Нoъv сan suсh a riсh thеoгеtiсаlstruсturе as population gеIlеtiсsfail so сomplеtеly to сopе with the Ьody of faсt? Arе wе simply missing somе сritiсal rеvolutionary insight that in a flash will makе it аll сomе right' as thе Prinсiplе of ltеlativity did for the сontradiсtory еvidеnсе on thе prоpagatiorr of light? or is thе problеm morе pеrvading' morе dееply Ьuilt into thе struсturеof our sсiеnсе? I Ьеliеvеit is the lattеr.'' Onе rеason for thе impassе,hе arguеd, is that population gеnеtiсthеory is not ..еmpiriсally suffiсiеnt.''For ехamрlе, it inсludеs paramеtеrsthat сannot Ье mеasurеd dirесtly, or with suffiсiеnt aссurасy' to distinguish сlеarly Ьеtweеn altеrnativе сausal aссounts. Тhis rеflесts Lеwontirr's morе gеnеrаl еpistеmologiсal сonсеrns-indееd, his skеptiсism. Не is wе|l known-еvеn infamous-for pеrsistеntly quеstioning whеthеr gеnеtiсists аnd еvolutionary biologists сan possiЬly know what thеy want to knоW and oftеn сlaim to know. His сritiquеs of adaptationists(inсluding his I979 artiс|e..TlrеSpandrеls of San Мarсo and thе PanglossianParadigm''' сoauthorеd with Stеphеn Gould) and gеnеtiс dеtеrmirristsarе largеly еpistеmologiсal.Adaptationists

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Lец,сllttin ar-rdgеnеtiс dеtеrminists do not know еnough aЬout thе inhеritanсе of thе traits thеy study and thе еvolutionary forсеs aсting on thosе trаits. Morеovеr, no onе knows. This is a сеntral motif of Lеwontin's Gепetiс Bсszl and his stibsеquеntrеviеws of tlrе statе of population gеnеtiсs'Thе titlе сlf onе suсh rеviеw wеll illustratеshis disсontеnt еvеn with mеtlrods of his oWIl dеvising: ..Еlесtrophorеsisin thе Dеvеlopmеnt of Еvolutionary Gеnеtiсs:Мilеstonе or Millstоnе?'' (1991I. A sесond rеаson for thе fаilurе of thеory to mаkе sеnsеof data in populаtion gеnеtiсsis that pattеr.nsof gеnеtiс vаriation сan Ье duе in lаrrgеpart to ..history''-6or instanсе, not just whiсh еnvironmеnts a population ехpеriеnсеs' Ьut thе ordеr in whiсh thosе еnvirtlnmеntsare еnсountеrеd(Lеwontin |967). Population gеnеtiс сhеory,howеvеr, is an еquiliЬrir.rmthеory tlrilt disсoLlntshistoгiсirlсontingеnсiеs.Lеwontin's disсussiorrof thе ahistoriсal сharaсtеr of populаtion gеnеtiсs is partly еpistеmologiсal: history is ignorеd largеly Ьeсausеthе past is so oftеn unrесovеraЬlе.But it is also partly politiсal. In population gеnеtiсs,as in othеr :rrеilsof thе rraturаl аnd soсiаl sсiеnсеs,еquiliЬrium thеoriеs prеvailеd in tlrе twеntiеtl.lсеntury in part Ьесausе ..prеoссupаtionwith of a vеry gеnеral staЬility'' (Lеwontin 1974,269). For Lеwontin, thе way forward in sсiеnсе involvеs, in part, ехposing thе idеologiеs that hеlp to pеrpеtu:ltеinсorrесt viеws of сhе world' For ехamplе' hе аrguеd tn cеnetic Bс-.istlrаt thе сlаssiсal/Ьalanсесontrovеrsyсould not Ье understood without taking into aссount thе сonfliсting politiсal idеals of Mullеr and Dobzhansky. A сommon mistakе of Mullеr аnd DсlЬzhansky' ассording t
Ьasес]in thе way that m ally пrorе a сasе of shoц liеvеrs in thе gеnеtiс Ьas Lеwontin's еpisrеmrl matеrialism, whiсh play

D i . r | е с t i с e lm а r е r i а l i mеtlrod for solvir-rgpar sis providеs an ovеrv forms of dogmatism a thаt history maу' lеav Ьессrrrring arе duаl as1 aгrd that thе сonditiсl Ье dеstroyеd Ьy thе р oЬjесts in timе аnd sp tiorrs.Rеmеmbеr tlrаt Ье lost whеn phеnom thаt all thе othеr сavt appliсation to diffеrе ( L е v i n sа n d L е ш ' r l l l r i B|вLIoGRAPHY

Gould, S. J.' and R. С-.Lеw Pаr-rglоssiаn paгlrdigm сl|thе I|oуаl SсlсiсtуtI HuЬЬv,J. I-.'and R. (-. [-е hсtеrсlzygosity in natu in Drosophilа psеudо

I . с v i n s 'R . ' а n d R . [ , е r r ' . l l l R' I-еw
Lешoпtin about thе inhеritanсе of thе ing on tlrosеtraits. Morеovеr' ontin's Gепetiс Basis and his Thе titlе of onе suсh 4еr-rеtiсs. mеthodsоf his own dеvising: ionary Gеnеtiсs:Milеstonе or mаkе sеnsеof data in popula_ )n сan Ье duе in laгgе part to ) n m е n r sa p o p u l а t i o n е x p е r i (Lеwontin 1 t sa r е е l ] с o u n t е r е d rn еquilibrium thеoгy that dis_ :ussionоf thе Lrhistoriсalсharmologiсal: history is ignorеd Ьlе. But it is also partly politiof thе nаtuгаl and soсial sсi)ntiеthсеntury in part Ьесausе '' (L,еrь,ontin1974, 269)' nvolvеs,in part, еxposing thе ws of thе woгld. For ехampiе, [anсесontrovеrsyсould not Ье сonfliсting politiсal ideals of nsky, aссording to Lеwontin, ехistingpilttеrnsof gеnеtiс dilr his own part' hе has сlaimеd, n d r l r th t l w m u с h d i v е г s i t yе x i n g t t l d е с i d еh o w t o o r g а n i z е uld usе our Ьеst undеrstanding .h to dеtеrminе what intеrvеnlpirе to (Lеwontin еt al. 2001, linеs, Lеwоntin has oftеn Ьееn ;ism сonсеrninggеnеtiс dеtеr:еad.As hе quotеs Karl Маrх, cuсtsof сirсumstanсеsand upr r е p г o d t r с t so f o t h е r с i г с u m rhat it is mеn that сhangе r е е d sе d i r с a t i n g '(. L е w o n t i n е t эlitiсal signifiсanсe for his own thе sorts of studiеsthat hе inionlnеnt of Human Divегsity,'' i a t i o nw i t h i n s о . с a l l е dг а с е s i s 'iation Ьеtwееnraсеs (sее also rnd аll thе othеr soсiаl and po_ ?m' arе thus not Ьiologiсally

Ьаsеdin thе way that mаny h:rd supposеd.Aссording to Lеwontin, this is геally more a сasе oi showing that gеnеtiсsis not as politiсally signifiс:rntas Ьеliеvеrsin thе gеnеtiс Ьаsis of raсial diffеrеnсеshad imaginеd. Lеwontin's еpistеmolс>giсal and politiсal intеrеstsmеrgе in his dialесtiсal mаtеrialism.whiсh plays a сautionirry,hеuristiс rolе in his work: Dialесtiсаl matеrialisrn is not, аnd tlеvег lras Ьеen, 21programmatiс mеthod for solving partiсular physiсal problеms. Rathеr, dialесtiсal analy. sis providеs an ovеrviеw аnd a sеt of waгnirrg signs аgаinsr paгtiсular forms of dogmatism and nаrrownеss оf thought. It tеils us, ..RеmеmЬеr that history mаy lеаvе аn impoгtarrt traсе. RеmеmЬег that Ьеing and Ьесoming аrе dual aspесtsоf naturе. Rеmеrnbеr that сonditions сhangе and that thе сonditions nесrssary to thе initiаtion of somе proсеss may Ье dеstroyеd Ьy thе proсеss itsеlf. RеmеmЬеr to pay аttеnrion to rеal oЬjесtsin timе and strraсе аnd nоt losе thеm in uttеrly idеalizеd aЬstraс. tions. Rеmеmbеr that qualitativе еffесtsof соntеxt and intеraсtion may Ье lost whеn phеnomеna arе isolаtеd.''And aЬovе all еlsе' ..RеmеmЬеr that аll thе оthеr сavеats аrе onlу rеnrindеrsand warning signs whоsе appliсation to diffеrеnt сirсumstаnсеsof thе rеal world is сontingеnt.'' (Lеvirrsand Lеu.ontin 198.5,|91-|92) B|вLIoGRAPHY 1979.Thе spandrеlsof Sаn Магсo arrdthе Gould,S..|..ant1R. С. Lеш,ontln, programmе.Proсеediпgs Panglоssiаn paradigm:A сritiquеof thе adaptationisr сlftllс Rсry'аl Sсlсiсtусl|.Loпdсlп,Sеriеsts 20.5:'581_598. HuЬЬy,.|.L., arrdR. С. Lеwontirl.1'966.A mоlесularapproaсhto thе studyof gеniс hеtеrozygosity оf аllеlеsаt diffеrеntloсi irrnaturalрopulations.l. Тhе nLrmЬег in Drсlsсlphilаpsеudllr'lbscut.а. Gепetics54:577_594. In R. Lеvinsand Lеr.ins,R.' and R. Lеrvontirr. 198.5.Thе proЬlеnrof l,ysеnkoism. МA: R. Lеwontir-r, еds.,Т}c Diаlссtiсаltsiologist, \6З-196. СarnЬridgе, HarvardUnivеrsityPrеss. Thе nеw gospеlin gеnеtiсs? Lеwotrtin,R. с. l964. A molесtrlar mеssiаh: Sсicпсе 1.45566-567. |967.TЬeprir-rсiplе in еvolution.In P. S. Мсlorlrеadilnd of histсlтiсitу М. М. Kаplаn, eds.,МаthemаtiсаlСhаllепgеsto thе Nеo-Dаrшiltiап .Wistаr Intеrprеtаtit,lп Philаdеlрhiа: InstitutеPrеss.
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Linпаeus Lеwontin, R. с., S. Rоsе' аnd L. J. Kamin. 1984. No, iп Оиr Gепes: Biolсlgу, Ideologу, апd Нцmап Nаturе. Nеw York: Panthеon. Singh' R. S., and С. B. KrimЬa, еds. 2000. Еuсllutioпаrу Gепеtiсs frс-lmМrllесulеs to Мorpholсlgу. СamЬridgе: СamЬridgе Univеrsity Prеss. Singh, R. S., аnd М. K. Uyеnoyama, еds. 2О04. Thе Еuсllutioп of Populаtitlп Biсllogу. СamЬridgе: СamЬridgе Univеrsity Prеss. -I.B.

Linnaеus,Сarl (or Сarl von Linnё) (|7О7_|77s) Born and raisеd in Swеdеn, Сarl Linnaеus was passionatеaЬout Ьotany from his youth. By thе timе hе wеnt to Holland tn |7З5 to finish his mеdiсal dеgrее, hе possеssеdan imprеssivеknowlеdgе of thе known kinds of plants and animals. Thеrе hе was hirеd to managе аnd сatalog thе hugе privatе musеum' Zoo' hеrЬarium, and Ьotaniсal gаrdеn of Gеorgе Сlifford' a wеalthy mеrсhant. By thе timе LinnaеLrsrеturnеd to Swеdеn in 1'7З8,hе had puЬ. lishеd numеrous works, all in Latin, that sеt out thе rulеs, framеwork' and сatalogs of аll thе plant gеnеra thеn known. Hе was a foundеr and thе first prеsidеnt of thе Swеdish Aсadеmy of Sсiеnсеs.In |741 hе was hirеd Ьy thе Univеrsity of Uppsala, whеrе hе taught for thе nехt 3з yеars. Ехеrting a dominating influеnсе upon natural history (Ьotany and zoology), hе attraсtеd studеnts from асross Еuropе, somе of whom hе sеnt on сollесting trips ovеrsеas.Hе ехсhangеd lеttеrs with distant naturalists who sеnt him spесimеns.Most important, hе frеquеntly produсеd nеw еditions of his сatalogs of plant and animals: Sуstemа Naturаe (12 еditions Ьеtwееn 1735 and 1768)' Generа Plапtаrцm (six editions from |7З7 to 1764), and Speсiеs Plапtctrцm (thrеееditions from 175З to 1764). Thеsе works providеd naturalists of all nations with onе сеntral, wеll-organizеd rеgistеrof namеs. Linnaеus'sсatalogs wеrе thе sеarсh еnginеsof thеir day. Linnaеus workеd in thе сontеxt of thе worldwidе сollесtion of natural history spесimеns that aссompaniеd thе ехploration, tradе, аnd сolonization сarriеd out Ьy Еuropеan govеrnmеntsand еntrеprеnеurs.His partiсular talеnts, whiсh inсludеd unlovaЬlе traits likе еgotism and an oЬsеssion with making lists, еquipped him to produсе an ехpandaЬlе rеgistеrof thе divеrsity of living things. Although hе ехpесtеd thе nехt gеnеration ro сomplеtе thе projесt, Ьiologistsin latеr сеnturiеs,inсluding our own' сontinuе to еnсountеr spесiеsnot prеviously dеsсriЬеd.Thе projесt of making an invеntory of lifе is still unfinishеd. Linnaеus's systеm wаs striсtly hiеrarсhiсal, gгouping similar spесiеsinto a gеnus' similar gеnеra into an ordеr' ordеrs into a сlass, and сlassеs into a kingdom. Latеr taхonomists addеd familiеs (Ьеlow ordеr) and phyla (Ьеlow kingdom), as wеll as suЬordеrs' supеrordеrs,and thе likе; this ехpandеd the hiеrarсhy without сhanging its prinсiplеs. Linnaеus Ьеgan thе сonvеniеnt praсtiсе of attaсhing a propеr namе to еaсh individual group, using a traditional onе whеrе possiЬlе (suсh as Avеs and Pisсеs' Latin for Ьird and fish, rеspесtivеly)Ьut сoining a nеW onе if nееdеd (suсh as Маmmaliа for thе сlаss

that inсludеd whalеs z inal nomеnсlaturе, th gеnеriс namе plus a m. and Homo sаpieпs (Ь

ordеr to fit thе thous aЬЬrеviations, omittе Ьlе. Hе inсludеd сitat liographiс guidе or in Linnaеus,s systеm f sophiсal foundations lеarnеd aЬout rесеnt stamеn and pistil, as .

vеntеd сlassеsЬasеdt Ьasеd on dеtails of th Ьasеd on only a fеw Ьotanists сould usе (а forward to thе day v natural onеs. At thе l.

of fеaturеs' inсluding sion of thе wholе pla a сonfusing mixturе '

spесiеs.In his сlassifi еvеr sееmеd to work insесts' and fins for fi naеus aimеd at thе lo1 terms gепus and s1lес ill-foundеd сlaim tha his aims and proсеdu At thе start of his < in latеr yеars hе saw think that God had с arising latеr. Мost of Bесausе visiЬlе varia thе еntirе rangе is nс sult of еnсourаging spесiеs.Linnaеus haс his studеnts to study at what dаtе diffеrеn Ьalanсе of naturе. Thе most rеmark Was that thе struсtur to Ье сongеnial to th groups. Thе old idеa did thе prеdiсtion с Baptistе Lamarсk th;

L'l|1,7аеus

п Оur Gепes: Bioltlg1,,

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у Gепеtiсs from Мtllесulеs tl-l

'f.,ii,,,,,, o|.Populаtiслt -J.ts.

)7-r778) ssionatеaЬout Ьotany from 35 to finish his mеdiсal dе: known kinds of plants and talog thе hugе privatе muGеorgе Сlifford, a wеalthy е d е ni n 1 7 3 8 , h е h a d p u Ь _ : thе гulеs' framеwсlrk, and wаs а foundеr and thе first п 7741 hе was hirеd Ьy the n е х t . ] 3 y е a г s .Е х е г t i n g а ltany and zoology), hе atvhom hе sеnt on сo|lесting tt nаturаlistsrvho sеnt him : е dn е w е d i t i o n sо f h i s с a t а еditions Ьеtwееn 17З5 and 7З7 to |764I' and Spcсiеs Гhеsеworks providеd naturizеdrеgistеrof namеs. Linduу. idе сolIесtiоnоf nаtцгal hiso n , t r a d е ,а n d с o l o n i z a t i o n prеnеurs.His partiсular talism and an oЬsеssion with l a Ь l еr е g i s t е or f г h е d i v е r s i r y gеnеrationto соmplеtе thе .own, сotltinuеto еnсountеr laking an invеntory of lifе is luping similar spесiеsinto a l а сlаss, аnd сlаssеs into a эw ordеr) and phyla (below l thе likе; this ехpаrndеd thе l а е u sЬ е g а n t h е с o n v е n i е n t viduаl group' using a tradiсеs, Latin for Ьird and fish, :has Мanrmаlia for thе сlass

that inсludеd whalеs and humans). Hе also introduсеd what is сallеd Ьinomiпal nonrеnсlaturе' that is, always using two words to namе а spесiеs, thе gеnеriсnamе plus a rnodifiеr, suсh as Сапis lupus (wolf), Сапis fаmiliаrls (dog), and I7omсl sаpieпs (human). (Сurrеnt praсtiсе is to italiсizе suсh namеs.) In oгdеr to fit thе thousands of spесiеs into manаgеaЬlе volumеs, hе invеntеd аЬЬrеviations,omittеd illustrations,and madе dеsсriptions as short аs possiЬlе. Hе inсludеd сitations of othеr authors' so his works funсtionеd as a biЬliographiс guidе or irrdеx to thе sсiеntifiсlitеraturе. Linnаецs's sysrеm foг flowеring plants stimulаtеd disсussion of thе philosophiсal fоundations оf сlassifiсation. At thе start of his сarееr hе had lеarnеd aЬout rесеnt thеoriеs intеrprеting thе сеntral parts of a flowеr, thе stamеn and pistil, as organs of malе and fепrаlеsехuаl rеproduсtion. Hе invеntеd сlassеsЬasеd on thе numЬеr and arrangеnrеntof staпlеns and ordеrs basеd on dеtails of thе pistil or thе fruit. Thеsе groups Wеrе artifiсial, Ьеing basеd on only a fеw сharасtеristiсs,Ьut thеy gavе а kеy thаt еvеn inехpеrt Ьotanistsсould usе (as long as thе spесimеn was in flоwеr). Linnaеus lookеd forwаrd to thе day whеn thеsе artifiсial groups с
бd/

Liuiпg Лossl/-. сlumps, sеts Within sеts! sееmеd naturе's own. This unехpесtеd and gradually еmеrging piсturе Was thе gгеat phеnomеnon lеft to Linnaеus's hеirs. Unlikе Lamarсk's

thеory, whiсh

grеW Out of thе сl,rain of Ьeing, Сharlеs Darwin's

thеory dirесtly addrеssеd thе hiеrаrсhiсal pattеrn of Linnaеan taхonomy by positing a high rаtе of еxtinсtion

and a prinсiplе сlf divеrgеIrсе.

BlвLIoGRAPHY B]unt, W. 197|. Thе Сompleаt Nаtиrаlist: A Life of Liппaeиs. Nеw York: Viking Prеss. F.ringsm1,r,T., еd. 1994. Liппаеtts: Thе Маn апd Нis Work. Сanton' МA: Sсiеnсе Нistory PuЬliсatiоIrs. L a r s o n ,I . L . 1 9 7 \ ' R е а s с l п а n d Е х p e r i е п с е : T h е R е 1 l r е s e п t а t i с l n N o fа t u r а l o r d e r i п thе Work oi Саrl uсllt Liппё. Bеrkеlе,v:Univеrsity of С:rliforniа Prеss. Linnаеus, С. |713. Gaterа plапtаrum, ror'rmql|е сhаrасterеs паtttrаIеs,sесuпdиlп пumеrum, figurаm, situm, i prUpоrti()nеm omпium fruсtifiсаtirlnis pdrtium. Еditio sесuпdа, псlпlillibus plапtаruпt Gаlliсis loсupletаtа. Pаris: Мiсhаеl Anronius David. 175З. Spесies plапtаrum: Ехhibепtеs plапtаs ritе сogпitаs, АD gепеrа rеlаtаs, сum tliffеrепtiis spесфсis, псltпiпibus triuiаlibus, sупсlпуmis sеlесtis, loсis паtаlibus, sесипdum sуstеmа sехuаlе digеstаs,2 vols. Inrrоduсtion Ьy \f. T. Stеarn. London: Ray Soсiеty. |758. Sуstеmа пLttЦrасpс| rеgпа triа паturtlе, sесuпdum сlаssеs, rlrdiпеs' gе,lerа' spссiеs, сuпl сhаrасteribus, diffеrепtiis, sупrlпуmis, /tlсls. London: British Musеum (N:1turalHistory). Nli.illеr-Willе,S. 2001. Ga гdеns of раrаdisе.Епdе.tt,oиr25: 49-54. .!ИеЬsitе. http://www.с1 8.rutgегs.еdu/pr/lс/proj.l in.html. Рro jесt l,innaеus. .!(insoг' lvl. Р. 2006. Linnaеus's Ьiologу was not еssеntialist.Аппаls of the Мissouri -NI'Р.\X/. B
Living fossils Living fossils аrе dеfinеd infoгmally; thе tеrm doеs not havе a prесisе tесhniсal dеfinition' Living aniпlals аnd plarrtstЬat lrаvе сhаrrgеdvеry littlе irr forrn and Ьеhavior' сompаrеd with their rеmotе anсеstors,arе said to Ье living fossils. Also, living rеliсts of groups that wеrе muсh morе divеrsе far Ьасk in thе gеologiс past may Ье сallеd living fossils. Bесausееvolutionary сhаrngеtеr-rds to Ье сonсеntratеdin еpisodеs of rapid divеrsifiсationеarly in thе еxpansion of nеw groups of organisms, thеsесatеgoriеSlаrgеly ovеrlaP. Сhaгlеs Darwin first appliеd thе сontradiсtory еxprеssion ..living fossil'' to the platypus (sее figurе) and tlre lungfish' as wеll as Pсllуptеrиs, thе Afriсan Ьiсhirs and thеir rеlativе,thе rееdfislr.Thеsе аnimаls all rеt;rinprimitivе сharaсtеristiсs that show thеm to Ье morе or lеss intеrmеdiatе Ьеtwееn typiсal mаmmals and rеptilеs' or mаjor groups of living Ьorry fishеs, as Darwin notеd. Thе platypus lаys еggs' Ьut suсklеs its young. It has hair аnd is warm Ьloodеd, Ьut it hаs a lеss сonstаnt Ьody tеmpеratuгеthan typiсal пrаmmals. Еarliеr naturalists,wlro saw thе animal woгld as а fiхеd sеt of sеparatеlyсrе. atеd ..typеs,',rеgardеd thеsе сrеaturеsas anomaliеs.To Darwin, and now to us' thеSе living fossils arе thе lеast пlodifiеd dеsсеndantsof rеmсrtе'еxtil.lсt anсеstors.Thosе anсеstors'whеn thеy livеd, wеrе сritiсal links in thе Ьranсhing еvolutionarу histor),of highеr anirrralsand plants.

Thе duсk-billеdplatypL suсh odd org'аnisms'th and groups of spесiеs'r сallеd living fossils'wil ( D a r w i n1 8 - 5 9 , 4 8 6 ) .

Living rеlativеsof a tinсt, arе oссаsionallу ing fossils' еspесiallу thеsе is thе сoеlaсаnt l i o n y е a r s а g o ) 'w a s d fossil spесiеsrеprеsеn voniаn (365 rrrillionyt

l h е l t v l n gс o е t а с e n t and a ioint within its organs and еyеs froln South Afriсa in 1938 sinсе Ьееn сaught ofi nеar Madagasсar. Rе latеd spесiеs has Ьее Сеlеbеs, in Indonеsia Lаtimеriа has not t span of thе spесiеsL. modеst wаys from irs to thе gеnus МасrrlpL tiсs of Lаtitпеriа that gеnus-a сlustеr of сl Thеrе sееtrrsto Ье r small groups of сlosе littlе сhangе irr fоrm. r

Liuiпg Fossl/s his unеxpесtеd and gradually [t to Linnaеus's hеirs. Unlikе r of Ьеing, Сharlеs Darwin's :n of Linnaеan taxonomy

Ьy

э of divеrgеnсе.

ппаeиs.Nеw York: Viking Prеss. s Work. Сanton, МA: Sсiеnсе resепtаtirlпof NаturаI Оrder iп y of Сalifornia Prеss. Lrасtеrеs паturаlеs, s есuпdum ium frисtф cаtioпis pаrtium. |сИplеtсttсl.Paris: Мiсhaеl : ritе cogпitаs, AD gепеrа ,,iаIibus,sупoпуmis sеIесtts, ras.2 vols. Introduсtion Ьy э, sесuпdum сlаssеs,ordinеs, :упопуmis' /с,lсis. London шr 25 49-54. j.lin.html. 1u/pr/lс/pro n t i а l i s tА . ппаlsof thе Мissoиri

-М.P,w.

oеs not havе a prесisе tесhnivе сhangеd vеry littlе in form jtors' аrе said to Ье living fоsh morе divеrsе far Ьaсk in thе tsе еvolutionary сhangе tеnds с a t i o nе а г l y i n t h е е x p a n s i o n rgеly ovеrlap. y ехprеssion ..living fossil'' to е|| as Polуptеrus, t|1eAfriсan mals a1lrеtain primitivе сharintеrmеdiatе Ьеtwееn typiсal ving Ьony fishеs' as Darwin эung.It has hair and is warm гaturеthan typiсal mammals. s a fiхеd sеt of sеparatеly сrеaliеs.To Darwin, and now to е s с е n d а n tosf r е m o t е , е х t i n с t :rесгitiсаllinks in thе Ьranсhplants.

Thе duсk-Ьillеdplatypus'thе mаmmаl tlrat lays еggs.Darwin was fаsсinatеdЬy ..Spесiеs suсh odd organisms,thirrkingthеm highly signifiсantfor his purposеs. and groups of spесiеs,whiсh аrе саllеd aЬеrгant'and whiсh may fаnсifullyЬе саllеdliving fossils,will aid us in fсlrminga piсturеof thе anсiеrrtfсlrmsof lifе'' ( D a r w i n1 8 5 9 , 4 8 6 ) .

Living rеlativеsof animals long rесognizеdas fсlssils,Ьut thought to Ье ехtinсt' arе oссasionally disсovеrеd.Thеy arе most apt tсl Ье rеfеrrеd to as living fossils, еspесially in thе popularizatitln of sсiеnсе.Thе most familiar of thеsе is thе сoеlасanth.Thе first fossil сoеlaсanth, of Pеrmian agе (255 million yеars ago), was dеsсriЬеdЬy Louis Agassiz in 1839. Today, 70 or morе fossil speсiеs rеprеsеnting 27 genera arе known, ranging from thе Latе Dеvonian (365 million yеars ago) to thе l-atе Сrеtaсеous (80 miliion yеars ago). Thе living сoеlaсanth' Lаtimеriа, rеtains сharaсtеristiсlimЬ-likе stalkеd fins and a joint within its rеlativеly primitivе brаinс:rsеthat sеparatеsthе nasal organs and еyеs from thе еars аnd Ьrain. I'аtimеriа was first disсovеrеd off South Afriсa in 19З8. Many additional spесimеnstlf thе sаmе spесiеshavе sinсе bееn сaught off southеastAfriсa and adjaсеnt t() thе Сomoro Islands, nеar Madagasсar. Rесеntly, onе spесimеn of a dif{еrеntЬut vеry сlosеly rеlatеd spесiеshas Ьееn found on thе othеr sidе of thе Indian Oсеan, off thе Сеlеbеs,in Indonеsia. Lаtimеriа has not Ьееn found in thе fossil rесord, so thе еvсllutionarytimе span of thе spесiеs Lаtimеriа сhаlцmпае is unknown. It diffеrs in only vеry modеst ways from its nеarеstrеlativе' a Latе Сrеtaсеous сoеlaсаnth assignеd to thе gеnus Масropomа. Striсtly spеaking,it is thе сonsеrvаtivесharaсtеristiсs of Lаtiшeriа that arе unеquivoсally living fossils, and not thе spесiеsor gеnus-a сlustеr of сlosеly rеlatеd spесiеs-in whiсh thеy oссur. Thеrе sееmsto Ье nсl singlе ехplanation for thе long-ссlntinuеdsurvivаl of small groups of сlosеly rеlatеd еvolving lirrеagеs,with limitеd spесiatiоn and littlе сhangе in form. Arthur Сonan Doylе imaginеd dirrosaursаnd ptеrodaсtyls

689

690

Liuiпg Fossils surviving in his Lс;sr World' Ьasеd in part on his knowlеdgе of thе inaссеssiЬlе Roraima Plаtеau' on thе bordеr of Vеnеzuеla and Guyana. Somе living fossils do oссur in rеmotе, isolatеd rеgions, whеrе thеy havе аvoidеd intеraсtion with nеwly еvolvеd сompеtitors. Thе platypus and its spiny, hеdgеhog-likеrеlаtivе, thе есhidna, livе only in Australia. Sphеrrodontids,rеlativеly unspесializеd anсеstors of modеrn lizards, wеrе modеratеly divеrsе and widеly distriЬutеd around thе world during thе еarlу Меsozoiс. Today' two speсiеs of tuatara' thеir only living сlosе rеlativеs, arе rеstriсtеd to small islands off Nеw Zеaland. In сontrast, thе few living spесies of |'lаutilиs and thе hoгsеshoе сraЬs havе widе gеogrаphiс distriЬuttons. Nаutilus poпryilius, thе mоst сommon and variaЬlе of thеsесеphalopods with еlеgantсhаmЬегеdshеlls,rangеs from thе Grеat Barriеr Rееf to Nеw Guinеa, thе Philippinеs, and oсеaniс arсhipеlagos as far out in thе Paсifiс as Fiji. Fivе distinсt spесiеsof Nаutilus arе known. Typiсally, thеsе animals livе at dеpths of 100 to 400 mеtеrs or morе' on stееplysloping sеa Ьottoпrs,сlosе in аgainst сoral rееfs.Рopulations living o{f isolatеd oсeaniс islands display limitеd variation. Somе сonstitutе distinсt spесiеs,whilе othеrs arе rеgardеd as loсal suЬspесiеsof Nацtilus pompilius' This has promptеd thе rесеnt infеrеnсе that Nаиtillts is сurrеntly ехpanding its divеrsity, in a modеst burst of spесiation.To put this in сontехt' notе that thе spесiеsand gеnеra of anсiеnt Раlеozoiс nautiloids havе Ьееn assignеdto ovеr 125 familiеs, with an ехtraordinarу variеty of sliеll shаpesand modеs of lifе. Thе prolifiс divеrsity of nautiloids was rеpеatеdlyсut Ьaсk in mаjor Palеozoiс ехtinсtion еvеnts.A furthеr shаrp rеduсtion oссurrеd nеar thе еnd оf thе Triassiс (210 million yеars ago). Sinсе tl.lеn,thе group has dwindlеd to thе singlе gеnus that survivеs today. Thе horsеshoе сraЬs havе nеvеr Ьееn vеry divеrsе, thгoughout thеir long history. Fortns not dissimilar to thе living animals first appеarеd during thе S i l u r i a n ( a p p r o х i m a t e | у4 2 5 m i l l i о n y е а r s а g o ) . H o r s е s h o е с r a Ь s ' е x t е r n a l skеlеtons arе not as еasily prеsеrvеd as mollusk shеlls, so thеir fossil rесord may bе lеss сomplеtе. НOwеvеr, no morе than еight gеnеra сan сurrеntly Ье infеrrеd to havе livеd аt any onе timе. Thrее gеnеra arе living today. Onе fаmiliar spесiеs,Limцlus polуphеmus, is aЬundant and widеly distriЬutеd, from }ylainе to Yuсatan in thе wеstеrn Atlantiс. Irr thе Irrdo-Paсifiс, two spесiеs rеprеsеnting two diffеrеnt gеnеra гangе from thе Bay of Bеngal to thе Philippinеs' and а third spесiеs rangеs from Bornеo to Japan. Likе Limulиs polуphemus, this last spесiеs has a largе сlimatiс rangе. It is also tolеrant of varyirrg salinity and othеr еnvironmеntal variaЬlеs. In this rеspесt' thе horsеshoе сrabs arе quitе unlikе Nаutilus, whiсh is tеmpегaturеsеnsitivе аnd сannot survivе in thе wаrm surfaсе watеrs of thе tropiсs, whеrе it livеs. Among living plants, thе sporе-Ьеaгingс1uЬtnossеsand horsеtails arе rе. liсts of groups thаt dominatеd vеgеtation of thе late Palеozoiс. Both arе widеly distriЬutеd gеogrаphiсally. Thе horsеtаils, also known as sсouring rushеs, arе limitеd to aЬout 30 spесiеs of a singlе gеnus. Typiсally, thеy arе oppoгtunistiс сolonists of wеt slopеs and rivеrbanks that arе frеqr-tеntly dis-

t u r Ь е d . A s i n r i l a rЬ а Ь i may bе thе сlldеst livir yеars old arе morphtl spесiеs' Giпgko bilоb, that it rеmаitrs ullсеrtа thе trее fеrn_likе сусaс Yangtzе Rivеr Ьasilr iг tolеranсе of еnvirсrnm

strеегs. l h е d е е p ( ) с е а nт l ( ) r-lnifoгtrrand сtlnstаn| Nonеthеlеss, it has m. lLrsk, Neoplliпа, witЬ othеr organs, is a dеер during thе еarly Palе among Ьivаlvеs at al: i n

largеly Ьееn displaсеd fееdillg adaptatiсlns.A thеir skеlеtons from g dеpths, Ьеlow thе zor-r sort still oссur in slral rrrilliоrryеars :rgo)оrrl1 arе thе stalkеd есhino prominеnt of all ;rnr spесiеs of stalkеd сrin а n d a t a Ь y s s a ld е p t h s and thе сoеlaсanth,сo displасеmеnts towаrd faun.r and tlrеn tlrоsес i r l n с e г s h o r еs е t r i n g 5 TЬе variеty of сirсtl that thеrе is nсl onе с plaсеs irr whiсlr to Ье n tion. Living fossils do thе fасt that thеy tеn major groups to whiсL has bееn a sресtruln (

spесiеs,grotrps of аvе from thе staЬlе аdаpt u i д l r l е .T r i l o Ь i rеm;.rin Ьut thеy finally suссu Thеiг |ong Jесlinе tг

from сhangеs in сomt Chаnсе, oцtпrсldеda thеir ultimatе dеmisе riеs and futLlrеprospс

Liuiпg Fossl/s (nowlеdgеof thе inассеssiЬlе l Guyarrа.Soпrеliving fossils еy havе avoidеd intеrасtion d its spiny, hеdgеhog-likе rеl_ dontids,геlativеlyul-lspесialеratеlу divеrsе zrnd widеly ,lеsozoiс.Тoday. two spесiеs .еstriсtеdto small islands off rnd thе horsеshoесraЬs havе 'lius' tЬe most сommon and rЬеrеdshеlls, rangеs from the tеs,and oсеaniс arсhipеlagоs эсiеsof Nаutilus arе known' to 400 mеtеrs or morе' on rl rееfs.Pоpulations living off on. Somе сonstitutе distinсt эесiеsof Nаlltilus pompilius' utilus is сurrеntly ехpanding put this in сontехt, notе that tiloids havе Ьееn assignеd to of shell shirpеsаnd modеs of :atеdlyсut Ьaсk in major Раtion oссurrеd nеar thе еnd of l, thе group hаs dwindlеd to ivеrsе'thrоughout thеir long rals first appеarеd during thе ,).Horsеslroе сraЬs' еxtеrnal < shеlls,sо thеir fossil rесord n еight gеnеra сan сurrеntly lrее gеnегa arе living today. rЬundarrtand widеly distriЬAtlantiс. In thе Indo-Paсifiс, .angеfrom thе Bay of Bеngаl from Bornеo to Japan. I-ikе rrgесlimatiс rangе. It is also LmеntalvariaЬlеs. In this rеtttillts' whicЬ is tепrpеraturerfaсе watеrs of thе ггopiсs, mossеsand horsеtails arе rеthе latе Palеozoiс. Both arе а i l s .a I s o k n o w n а s s с o u г i n g glе gеnus.Typiсally, thеy arе э а n k sr h а t а r е f r е q u е n г l yd i s -

turbеd. A similar hаЬitat was formеrly prеfеrrеd Ьy thе gingko trее, whiсh may Ье thе oldеst living spесiеs' Fоssil lеаvеs аnd wood up to 100 rniliion yеars old arе morphologiсally indistinguishaЬlе from thе singlе surviving spесiеs, Gingko bilrlbа, of this anсiеnt group. This plant is so distinсtivе tlrаt it rеrrrainsunсеrtаin whеthеr it is nrorе сlosеly rеlatеd to сonifеrs oг to thе trее fеrn_likе сyсads. Orrсе widеsplrеаd,thе gingko survivеd only in thе Yangtze Rivеr Ьаsin in Сhinа until its domеstiсation. Now, its Ьеauty and tolеranсе tlf еnvironmеntаl insults havе Ьrought thе gingko to many сity stгееts. Thе dееp с;сеanfloor is nеithеr as low in divеrsity of arrimal lifе rror as uniform and сonstаnt in its physiсаl сonditions as Was onсе supposеd. Noгrеthеlеss,it lras nlorе than its slrarе of living fossils. Тlrе сrееping mоllusk, Neoplliпа, wltЬ its сap_shapеd shеll and sеrial sеts of musсlеs and othеr organs, is a dееp-sеarеliсt of two familiеs that livеd irr shаllow watеr during thе early Pirlеozoiс. ProtoЬranсhs with simplе gills prеdominatе among Ьivalvеs irt aЬyssal dеpths; orr thе сontinеntal slrеlvеs thеy havе largеly Ьееn displaсеd Ьy morе advanсеd forms with vаriеd Ьurrowing and fееdingadаptations' Aпrong singlе-сеllеdforaminifеra, only thosе that Ьuild thеir skеlеtons fгom grairrs of prеехisting sеdir-rrеnt сan livе at thе grеаtеst dеpths, Ьеlow thе zonе аt whiсh сalсiurrrсаrЬonatе dissolvеs.Forams of this sort still оссur in slrallow Watеr haЬitats, Ьut in Сambrian timе (aЬor"rt510 million yеагs ago) tlrrl1,this prinritivе cr()up was prеsеnt.Мost striking of all arе thе stalkеd есlrinоdеrmspopularly known as sеa liliеs. z\mong tlrе most prominеnt of all аnimals in shallow-Watеr Palеozoiс faLrnas, about 80 spесiеsof stalkеd сгinoids suгvivе today, worldwidе' on сOntinеntal slopеs and at аЬyssal dеpths. Thеsе distriЬutions' togеthег witlr tlrosе of Nаutilus and thе сoеlaсanth.сorroЬoratе еvidеnсеfrom thе fossil rесord of suссеssivе displaсепlеntstoward dееpег Watеr' first of dеsсеndants of thе СamЬrian fашnaаnd thеn th
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Loreпz в|BLloGRAPHY Darwin, с' 1859.oп the Оrigiп сlfSpeсles.Lоr-rdon: John Мurra,v. Еldrеdgе,N., and S. М. Stanlсy,еds. 1984. Liuitlg Fсlssils.Nеw York: SрringеrVеrlag. Nаturе395:319_320. Forеy,P. l998. A lromеfrсlmhomеfor сoеlaсanths. Royеr,D. L., L.J. Нiсkеy,and S. L. !fling.200З.Есologiсаlсonsеrvatism in thе ..livingfossil'' CllzgДсl. Pаlеobiсllсlg1' 29: 84_1О4. of ..livingfоssils,''Аnпuаl Sсhopf,Т'J.М. 1984.Ratеsоf еvolutionand thе notior-r Reuiеulof Еаrth аnd PlапеtаrуSсiепсеs12 245-292. Nеw York: Thomson'K. S. 1991.Liuiпg Fсlssil:ТhеStorуof thе Ссlеlасazf/:. -R.D.К.Т. Nor.ton.

Lorеnz, Konrad Zachartas (1903-1989) Konrad L
at birds in pаrtiсular, l not so muсh Ьy aсquir. havior pattеrns, Ьuilt ..fixеd valuе. For thеsе lеasеd'' Ьy stimuli еmа In thе 1930s hе сonstrr rеlеаsing mесhanisпrs tеrns. At thе samе tim ing.'' LIе found thаt yo

rесognizе mеmЬеrs of formation at a Ьriеf, сl printеd'. upon thе ob thеir instinсtivе Ьеhаv е x а m p l е ' i s е х p o s е dt . thе imprinting pеriоd, than its own spесiеs. With his сhаrismat thе naturаl Ьеhaviora b o l d t h е o r i z i n g ,a п d l mаny rесrttits to thе n his popular Ьook. oи, madе еаrliеr as а biо most for attraсting thс i m p o r t a n с еo f s t u d v i n f o u n d i n g t h е s с i е n с еo i n с l r " r d i n tgh е a w a г d l whiсh hе sharеd with BIBLIOGRAPH

B u r k h a r d гR, . W . ' J r . 2 0

апd thе Ftluпdiпg tl Lоrеnz' K. Z. l94 l. Vеrl Heiпrotb. Еrg:iпzun 1966. Оп Аggrе !7orld. \)7Q-|91|..\1 vols. CзmЬridgе, М N i s h е t t ,А . | 9 7 6 . K о t t r а

Luсy (АustrаIopi

In еvеry sсiеntifiс fiеl< thгoughs that arе еndt all arе supеrsеdеdor dееpеr insights arе mа Thеrе is no douЬt tha

Luсу

Jоhn Мurray. ssl/s.Nеw York: Springеr\'lаturеЗ95: з19-З20. logiсal соnsеrvatism in thе -ionof ..livingfossils.''Aппuаl )o )

Сoеlасапtb. Nеw York: -R.D.K.Т.

)) l е d V i е n n е s еo г t h o p е d i сs u r s. Latеr' whеn hе Ьесamе fanеd that his maturе sсiеntifiс сеs hе dеvеlopеd in his youth Ьy rеaringand obsеrving an_ to lеarn things aЬout animal )ratorysсiеntistsor fiеld natiп |92З as a mеdiсal studеnt ',еrsity of Viеnna' еvеntually :ollеd at thе univеrsitу,s Zoor l 9 З З . M е a n w h i l е a. t h i s p r i LЬеrg,сlоsе to Viеnna, hе had rvations that would hеlp prog Gеrman ornithologists and rovidеd thе oЬsеrvational and 'ology, thе Ьiologiсal study of was аЬly supportеdand сom)n' a Dutсh naturalist. rary undеrstanding of living hods of сomparativе anatomy as еffесtivеlyas thеy сould Ье . сomparing thе innatе Ьеhavvеn morе valuaЬlе than сomo rесonstruсtingphylogеniеs. s a major monograph rn 1941 gееsе.Hе latеr put his Ьroad, . g е n е r а l l ya Ь o u t е v o l u t i o n a r у thе human mind apprеhеnds Larfproсеss. l and humаn Ьеhаvior in еvсl' f t h е p h y s i o I o g i с aсl а u s а t i o n : Ьеhaviorpattеrns. Looking

at Ьirds in partiсular, he insistеd that thеy arе adaptеd to thеir еnvironmеnts nоt so muсh Ьy aсquirеd knowlеdgе as by highly diffеrеntiatеd instinсtivе Ьеhavior pattеrns' Ьuilt up ovеr timе Ьy еvolution as a rеsult of thеir survival ..fixеd motor pattеrns'' to Ье еffесtivе, thеy nееdеd to Ье ..rеvaluе. For thеsе lеasеd'' Ьy stimuli еmanating from аppropriatе oЬjесts in thеir еnvironmеnt. ..rеlеasегs,''..innatе In thе 1930s hе сonstruсtеda thеory of instinсt fеaturing rеlеasing mесhanisms,'' aсtion-spесifiс еnеrgiеs' and innatе, fixеd motor pat..imprinttеrns. At thе samе timе, hе сallеd attеntion to thе phеnomеnon of ing.'' Hе found that young Ьirds suсh as jaсkdaws of gееsеdo not instinсtivеly rесognizе mеmЬеrs of thеir own spесiеs Ьut instеad normally aсquirе this in' ..imformation at aЬrief , сritiсal pеriod of thеir еarly dеvеlopmеnt. Thеy arе printеd'' upon thе oЬjесt that will suЬsеquеntly sеrvе to rеlеasе сеrtain of thеir instinсtivе Ьеhavior pattеrns. Howеvеr, if a young grеylag gosling, for еxamplе, is ехposеd to a human Ьеing instеad of а mothеr grеylag goosе in thе imprinting pеriod, thе gosling will Ьесomе imprintеd upon humans rathеr than its own spесiеs. With his сhаrismatiс, еxuЬеrant pеrsonality, his еxtеnsivе knowlеdgе of thе natural Ьеhavioral rеpеrtoirеs of a host of diffеrеnt animal spесiеs, his Ьold thеorizing, and his skills as a popularizеr, Lorеnz was aЬlе to attraсt many rесruits to thе nеw sсiеnсе of еthology. Сontrovеrsial in thе 1960s for his popular Ьook, Oz Аggrеssioп' and rесurrеntly сritiсizеd for statеmеnts hе madе еarliеr as a Ьiolоgist undеr thе Third Rеiсh, Lorеnz is rеmеmЬеrеd most for attraсting thе attеntion of zoologists and psyсhologists alikе to thе importanсе of studying animal Ьеhavior from a Ьiologiсal pеrspесtivе and for founding thе sсiеnсе of еthology. His work was rесognizеd Ьy many honors, inсluding thе award of thе 1973 Nobеl Prizе for Physiology or Mеdiсinе, whiсh hе sharеd with Karl von Frisсh and Niko Tinbеrgеn. BIBLIOGRAPHY Burkhardt,R. W., Jr. 2005. Pаttеrпsof Bеhаuiсlr:Koпrаd Lorепz, Niko Tiпbеrgеп, апd thе Fouпdingof Еtbсllogу.Сhiсаgo:Univеrsityof Сhiсago Prеss. an Anatidеn.In FestsсhriftО. Lorenz,K. Z. 1941r.VеrglеiсhеndеBеwеgungsstudiеn Hеiпroth.Еrg:inzungsЬand 3. loиrпаl filr Оrпithсllсlgiе89: 194-29З. |966. Оп Аggrеssioп,М. K. lfilson' trans.Nеw York: Hаrсourt, Brасеand !7orld. 1970-197I. StL|diеs in Апimаl апd Humап Behаuiour.R. Мartin' trаns.2 vols.Сembridgе,MA: HarvardUnivеrsityPrеss. NisЬеtt,^. 1976. Koпrаd Lorепz. Nеw York: Hаrсourt BrасеJovanoviсh.

R.vИB.

Luсy (AoкtrаIopithecusаfаrепsis) In еvеry sсiеntifiс fiеld of еndеavor thеrе arе сеrtain disсovеriеs and Ьrеakthroughs that arе еnduring and aсhiеvе somеwhat of an iсoniс naturе. Nеarly all arе supеrsеdеd or signifiсantly altеrеd whеn nеw finds сomе to light or dееpеr insights arе madе' Ьut thе сorе innovation or disсovеry is еvеrlasting. Thеrе is no douЬt that сonstruсts likе thе Big Bang, thе thеory of еvolution,

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I,ису thе thеory of gravitation' сontinеntal dгift, thе lаws of inhеritanсе' and many othеrs hаvе Ьееn еnhanсеd or modifiеd from thеir original manifсstations, Ьut thе сеntral idеa is still thеrе and thе сonсеpt сontinuеs to Ье known Ьy its original itеration. Looking Ьaсk on my сarееr as a palеoanthropologist-somеonе who studiеs human origins-I had oссasion ln 1974, in thе rеmotе dеsеrt rеgion of Еthiopia known as thе Afar Trianglе' to makе onе of thosе еnduring disсovеriеs. Shе was a 3.2 million-yеar-old human anсеstor who has Ьесomе pеrhаps thе most widеly сеlеbratеd disсovеry of a fossil human of thе twеntiеth сеntury. Known Ьy thе affесtionatе namе of Luсy (namеd aftеr thе Bеatlеs song ..Luсy in thе Sky with Diamonds''1 sее figurе), tЬis 40"Ь сomplеtе skеlеton (not inсluding thе Ьonеs of thе hands and fееt) еpitomizеs our fossil anсеstry. Luсy hаs Ьесomе a touсhstonе for сomparing and еvaluating all nеw fossil humаn finds. Еvеn for thosе who havе diffiсulty rеmеmЬеring hеr sсiеntifiс name, Аиstrаlopitheсus аfаrепsis, Ьringing up thе namе Luсy rings a Ьеll for еvеryonе:..Oh, yеah, that anсiеnt skеlеton from Afriсa!'' Onе of thе еssеntialquеstions thаt all humans ask is' ..!Иhеrеdid wе сomе from?'' Thеrе arе two ways to answеr this quеstion. Onе is to еvokе a сrеation story of how Wе wеrе сonсеivеd in somе sort of supеrnatural mannеr. Suсh ехplanations that arе Ьasеd on Ьеliеf diffеr from soсiеty to soсiеty' and ассеptanсеis prеmisеd on providing somе sort of spесial еvеnt or supеrnatural сausе, thе еvidеnсefor whiсh is invisiЬlе and availaЬlе only to thosе who havе faith. On thе othеr hand, palеoanthropologistsusе a sсiеntifiсapproaсh to сomprеhеnd thе сausе, сoursе' and timing of human еvolution. !Ие nееd not invokе spесial еxplanations or supеrnatrrrаlсausеs.Thе study of human origins is basеd on oЬsеrvaЬlе еvidеnсе that is availaЬlе to еvеryonе' rеgardlеssof thеir bеliеf systеm. Thеrе is a fossil rесoгd for humankind Ьuriеd in thе еarth's sеdimеnts. Luсy сomеs from a pеriod of timе whеn our anсеstors lookеd vеry apеlikе, with projесting fасеs' small Ьrains (onе quartеr thе sizе of a modеrn humаn brain), rеlativеly long arms (lеft ovеr from trее-livingprесuгsors),and сurvеd hand and foot Ьonеs (also from our аrЬorеal past).Howеvеr' thеsеanсеstors, somеtimеs сallеd ..apе-mеn,''possеssеda сardinal fеaturе that plaсеs thеm on thе еvоlutionary Ьranсh оf humans rathеr than apеs:Ьipеdalism.Bipеdalism is thе ability to stand and walk on two lеgs, a Ьеhavior that stands in powеrful сontrast to all othеr mammals, whiсh gеt around on all fours. Additionally' thеsе ..apе-mеn,''in сontrast to prеsеnt-dayhumans, wеrе prесultural, mеaning thеy wеrе inсapaЬlе of making and using еvеn rudimеntary stonе tools (thеy may havе utilizеd pеrishaЬlеraw matеrials likе wood as digging stiсks, Ьut thеsе itеms did not fossilizе). originally doсumеntеd with thе 1924 disсovеry in South Afriсa of thе ..Taung Сhild" (thе skull of an immatttre Аustrаlopithесus аfriсапus| Ьy thе latе Raymond Dart, thе diе Was сast that Afriса-or as Сharlеs Darwin rеfеrrеd to it' thе Daгk Сontinеnt-Was thе original hоmеlаnd for humanity. In thе dесadе aftеr thе puЬliсation of Darwin's сontrovеrsial,lasting, and pro-

Аustrаlopitheсus аfаrеп С. Johanson in thе Aiаr

Lису : lаws of inhеritanсе'and many r t h е i г o r i g i n a Im а n i f е s t a t i o n s , pt сontinuеs to Ье known by its opologist-somеonе who stud. in thе rеmotе dеsеrt rеgion of э onе of thosе еnduring disсovanсеstorwho has Ьесomе pеra fossil human of thе twеntiеth Luсy (namеd aftеr thе Bеatlеs gurе),this 40% сomplеtе skеlеl fееt)еpitomizеsour fossil annparing and еvaluаting all nеw diffiсulty rеmеmЬеring hеr sсi. ging up thе namе Luсy rings a lеton from Afriсa!'' ...W.hеrеdid wе сornе tns ask is, uеstion.onе is to еvokе a сrеrе sort of supеrnatural mannеr. fеr from soсiеty to soсiеty, and .t of spесial еvеnt or supеrnatuLndavailaЬlеonly to thosе who sе a sсiеntifiс approaсh to сomnan еvolution. .й/еnееd not ins е s .Т h е s t u d yo f h u m а n o r i g i n s aЬlе to еvеryonе' rеgardlеss of uriеd in thе еarth's sеdimеnts. anсеstorslookеd vеry apеlikе, tеr thе sizе of a modеrn human е-livingprесursors),and сurvеd )ast).Е{owеvеr'thеsе anсеstors' rdinal fеaturе that plaсеs thеm than apеs:Ьipеdalism. Bipеdallеgs, a Ьеhavior that stands in сh gеt around on all fours. Adеsеnt-dayhumans, wеrе prесuln g а n d u s i n gе v е n r u d i m е n t a r y raw matеrialslikе wood as digsсovеry in South Afriсa of thе strаlopithесusаfricапus) Ьy thе .riсa-oг аs Charlеs Darwin ге;inal homеland for humanity. In сontrovеrsial, lasting, and pro-

..Luсy,''wаs disсovеrеdby Donald Аustrаlopithеcusаfаrепsis.This spесimеn, С. Johansonin thе Afar trianglеof l,thiopia in 1974.

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Lucу foundly insightful volumе' oп thе Оrigin of Speciеs(1859)' it Ьесamеаpparеnt to sсholars that hеrе was an idеa so powеrful that it was сapaЬlе of еluсidating why spесiеs look and aсt thеy way thеy do. Furthеrmorе, it ехplainеd why thеrе is a sееmingly еndlеss divеrsity of lifе on еarth. Darwin knеw that living сrеaturеs look similar to еaсh othеr Ьесausе of сommon anсеstry. Hе Ьеliеvеd thеy arе еaсh uniquеly distinсt Ьесausеthе proсеss of natural sеlесtion has сraftеd thеm to aсt in mannеrs rеflесting thеir partiсular modеs of lifе. OЬsеrvations Ьy Darwin (1s71) and his сlosе friеnd Thomas Hеnry Huхlеy (1s63) lеd thеm to makе a tеstaЬlеprognostiсation. Thе prеmisе was that if hцmans and thе Afriсаn apеs look alikе, thеy mцst havе had a сommon anсеstor' and thе diffеrеnсеs arе rеlatеd tо how thеy bеhavе (apеsсlimЬ trееs,humans walk on thе ground). If thе thеory was сorrесt' аnd еvolution rеflесts сommon anсеstry as wеll as dеsсеnt with modifiсation (е.g.,humans lost thеir aЬility to loсomotе on all fours whеn thеy Ьесamе Ьipеdal), and that thе Afriсan apеs and humans sprang from a long. distant сommon Ьеginning, the oldеst traсеs of humanity rеsidе in Afriсa. That proposition is what thе Taung Сhild' Luсy, and thousands of othеr Afriсan fossils, havе vindiсatеd. Our dirесt anсеstors first еmеrgеd in Afriсa. Thе сommon anсеstor to thе Afriсan apеs and humans still еludеs rеsеarсhеrs and rеsts in somе unеxplorеd and unеxсavаtеd Afriсan stratum. Howеvеr' palеoanthropologists now piсturе Luсy's spесies as having livеd at an important infleсtion point in human evolution. Prior to Luсy, thе fossil rесord is sparsе. Now, human anсеstor fossils arе сoming to light at 4 million уears (А. аnаmeпsis)' at 4.4 million yеars (Ardipithесus rаmidus), and pеrhaps еvеn as far Ьaсk as 6 to 7 million уears (Sаhеlапthropus tchаdепsis). And truе to thе prеdiсtiоns madе Ьy thе thеory of еvolution, thеsе oldеr spесiеs arе looking morе and morе apеlikе, similar to thе prеsumеd morе primitivе сommon anсеstor. SuЬsеquеnt to Luсy, in morе rесеnt Afriсan sеdimеnts wе sеe еvidеnсе of thosе fеaturеs wе think of as morе humаnlikе. Аt 2.6 million yеars' stonе tools, fashionеd Ьy somе unknown human hand, arе found assoсiatеd with Ьutсhеrеd rеmains of sсavеngеd animals-mеat had еntеrеd thе human's diеt. Thеn, at around 2 million yеars' a nеar douЬling in Ьrain size (Нoшo hаbilis, I:Iomo rudolfeпsis, Homo еrgаster) is sееn in largеr skulls. Thе mod. еrn human Ьody form (long lеgs and rеlativеly short arms) appеars shortly thеrеaftеr, and thе first out-of-Afriсa ехpеriеnсе is doсumеntеd in thе RеpuЬliс of Gеorgia at 1.8 million уears (Homo erectus). Following a long pеriod of timе, during whiсh human spесiеs migratеd, еvolvеd, divеrsifiеd' and Ьесamе ехtinсt, еvеn morе modеrn humanlikе anсеstors suсh as Н, апtеcеssсlr and H. heidеIbеrgeпsis (500,000 to 1 million yеars ago) walkеd thе еarth. Thе first tantаlizing glimpsеs of art, еngrаvеd oсhrе, and thе spесializеd and highly insightful manufасturе of Ьonе tools appеar in Afriсa somе 70,000 to 100,000 yеars ago' two to thrее timеs еarliеr than in Еuropе. Now rеsеarсh has сonfirmеd thе oссurrеnсе of anatomiсally modеrn humans (Нomo sаpiепs' supposеdly ..wisе man'') at сlosе to 200'000 yеars ago in Afriсa (Еthiopia).

Humans, сapaЬlе of yеars ago. Somеtimеs l o r i g i n a l l yе v o I v е di n A l to thе dеmisе of suсh matеly to thе pеopling \йИеhаvе сomе from finеsus as humаn-Ьip s i z е , Ь o d i е so f m o d е r n appеaranсе in Afriсa. \ Ьеings with a сommon largеd, еnlightеnеd, anс с o m е f r o m ? . .w i I l u n i t е futurе. вIBLloGRAPHY

D a r w i n ,с . 1 8 5 9 .О п t h е | 87 |. Тhе Dсsсс Murray. Huхlеy, T. H. 186З,Еuid Norgatе. J о h a n s o nD, . С . 2 0 0 4 .L u Аustrаlоpithесиsаfаr 465-486. J o h а n s o nD' . С . . a n dM . , Nеw York: Simonan Johanson,D. С., and B. Е and Sсhustеr. K i m Ь е |W , . H . , Y . R a k .a l a f a r е n s i sN.е w Y o r k Tattеrsall,I., аndJ. Sсhw

Lyеll,Сharlеs(179

I n v a r i a Ь l yг е m е m Ь е г е Gеologу (first еdition ir was thе first сhild of an family, and of a Sсoгti only 15 yеars еarliеr Ь1 h i s f o r t u n еw h i l е s е r v i Lyеll livеd in southеrn I his BA from Oxford in took him oftеn ro сol l850s, to North Аmеri in thе 1820s, and Ьriеf аt thе nеW King's Coll mеans supplеmеntеdb pесially, from lесturing

Lуell ,сies(1859),it Ьесamе apparrl thаt it was сapaЬlе of еluсilo. Furthегmorе,it ехplаinеd on еаrth. ilar to еасh othеr Ьесaцsе of пniquеlydistinсt Ьесausе thе to aсt in mannеrs rеflесting Darwin (1871) and his сlosе to пtаkе а tеstаЬlеprognostiAfriсarr apеs look alikе, thеy iffеrеnсеsarе rеlatеd to how thе ground).If thе thеory was , as wеll as dеsсеntwith nrod)motеon аll fours whеn thеy lhumans sprang from a longэf humanity rеsidе in Afriсa. uсy, and thousands of othеr еstorsfirst еmеrgеd in Afriсa. and humans still еludеs геrnехсavatеd Afriсan stгatum. rсy'sspесiеsas having livеd at tion. Prior to Luсy, thе fossil rе сoming to light at 4 nrillion dipithесus rоmidus), and pег(Sаhеlапthr opus tchа deпsis) . ory of еvolution, thеsе oldеr imilaг to thе prеsumеd morе

Нumans, сapaЬlе of rеading and writing, еntеrеd Еuropе around 40,000 yеars ago. Somеtimеs known as Сrо-Мagnons' thesе human anсеstors had originally еvolvеd in Afriсa' and thеir сultural and intеlleсtual сapaсitiеs lеd to thе dеmisе of sr.rсhspесiеs as Nеandеrtals (З0,000 yеars ago) and ulti. matеly to thе pеopling of thе еntirе globе. .Wе havе сomе 1rom humЬlе Ьеginnings. Еaсh and еvеry fеaturе that dеfinеs us as human-Ьipеdalism, tool making, еnlargеd Ьrains, rеduсеd tooth sizе, Ьodiеs of modеrn proportions' pеrhaps еvеn languagе-first mаdе thеir appеaranсеin Afriса. Yеs, LuсУ hzis lеft a lеgaсy that unites us all аs humаn Ьеings with a сommon Ьеginning in Afгiсa, and it is my hopе that this еnlargеd, еnlightеnеd, and profound insight into thе quеstion of ...!fhеrе did wе сomе from?'' will unitе all humankind into a fruitful аnd lons-livеd сommon futurе. в|вLIoGRAPнY Dаrwin' с. 1859.Оп thе Оrigiп of Spесles.London:Jоhn Мurray. 1871. Thе Dеsсепtof Мап, апd Selесtiсlпiп Rеlаtioll /o Sex. London:John Мurray. Huхlеy,T. Н. 1863.Еуideпсеаs trl Маris Plасеiп Nаture, London:Williarnsand Norgarе. viеw of Johirnson,D. с. 2004. Luсy, thirty vеаrslatеr:An е-хptrndеd Austrаlopitbеas аfаrепsis.Jouпlаl of АnthropoklgiсаlRеsеаrсh60' no. 4: 465-486. Jоhaпson,D. С.' and М. A. Еdеy.1981.Luсу: Thе Bеgiппiпgsof Humапkiпd. Nеlv York: Simсlnаnd Sсhustеr. Johanson,D. С.' аnd B. Еdgаr. 2005. Frсlml-uс1,16 Lапguаgе,Nеr,r'Yоrk:Sirrron аnd Sсhustеr. KinrЬеl,!и. H., Y. Rak, and D. С. Johаnsoл.2О04.Thе Skиll of Australoрithесus аfarеnsis.Nеw York: Oxford UnivеrsityPrеss. Tаttеrsall,I., and J. Sсhwartz.200О,Ехtiпct Нumапs' Bouldеr,СO: !ИеstviеwPrеss.

-D.С.J.

sеdinrеntswе sеe еvidеnсе of e. Ьt )-.6 million yеars' stonе nd, arе found assoсiatеd with еat had еntеrеd thе human's douЬling in brain size (Homo ееn irr largеr skulls. Тhе mody short arms) appеars shortly е is doсumеntеd in thе RеpuЬtus). hiсh hurnan spесiеs migratеd, morе nrodеrrrhumаnlikе аnrgeпsis (500'000 to 1 million ling glimpsеs of art, еngrаvеd :ul manufaсturеof bonе tools гs аgo) two to thrее timеs еarе d t h е o с с u r r е n с еo f a n а t o l n i ..wisе man'') at сlosе to ;еdly

Lyеll,Сharlеs(t797_\875) Invariably rеmеmЬеrеd'еvеn on his gravеstonе'as thе author of Priпсiplеs of Gеologу (firstеditiotl in thrее volunrеs:1830, 1832, and 1833), Сharlеs Lyеll Wаs thе first сhild
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Lуеll Еvеntually knightеd, a friеrrсlсlf Prinсе AlЬеrt, .1ndаn advisеr to thr govеrnmеnt, hе Ьесilmе a prominеrrt r-riltionalfiguге witlr ir h
with what hе had с affiliations. That геform, as сonform gеology tс Ье еxplainеd by сal fiеd Ьy Nеwtoniаn thеory-a nеW vеr сonformaЬlе' potе a v o i d i n g d i v i s i v е 'i т sсiеnсе fгom Мosа сould only Ье mеt i roсks wеrе all prol аnd with thе samе i futurе' thе samе so insistеd, еntitlеdto by nrost gеologists knеw еnough of pr fесts. By геforming his primе amЬition сurrеnt low rеputе vatеd status сompa takеn to Ье thе hig Sсottish gеntry, Lyt thе sсiеnсеthat hе ] proSPесtivеprofеss еlitist anxiеty Was с Thе ultimatе sta transсеndеntanхiе (a Ьеliеvеr in Gоd l and govеrnmеntnс matеrial soul сomе Jеan-BaptistеLamа rеjесtеd in thе еarl1 mitmеnts аbout m rесord аs а progrеs suсh as Lamаrсk's сamе thеn to join С progrеssivе nесеssi tory of lifе on еarth many adaptivе сon1 ing suсh сontrаsts\ orizing as raising, thеology and morа Сhildlеss and dс hugеly inf]uеntialс any sсhoоl of сom1

I,уеll 'nd an advisеr to thе govеrnith a housе on Harlеy Strееt, г i n g p, | e с е i s i n W е s t m i n s t е r rе thе most formativе for thе an undеrgraduatе, Lyеll had nd thеn donе fiеldwork with l of oхford.taught gеology. for а fundamеntal and сomхford sсhool of gеology and ;сhool'sprimary mеntor (Сua l l i n t е g r а t i n gt h е H u t t o n i а n i r ( 1 8 0 2 ) ,w h o m С u v i е r h a d n s t a n tP r ё v o s t( 1 8 2 3 ' 1 8 2 5 ) , of thе Tеrtiary foгmations of his writings and with Pr6vost i г t о n .e s е с r е t a r ya t t h i s t i m е , ioсiеtyof London. Fitton, an )portivеfriеnd of thе FrеnсhLеmain writеr on gеology for ln had rеjесtеd Buсkland's еuiеш (seealso Fitton 1824, , Angliсan Quаrterlу Reuietu op' Was oxford's poеtry proLsof his univеrsity'and Buсk. L rumorеd to havе hеlpеd ly its liЬеrаl, Sсottish, Whig, oxonian hеgеmoniеs in thе Dеtеrmining Lyеll's viеw on 'm his family's and his own аnсе. Whеn Lyеll wгotе in .rtionsаs wеll as on gеology tsсious dissidеnt intrudеr. It \i7ith 3ht at King's Сollеgе. lеsignеdto Ье a Tory, AngliUnivеrsity Соllеgе' London, Whigs and hеadеd by Lyеll's Rеuiеlu foundеr. Lyеll's nеw rеfutе and rеplaсе wholеsalе just whеn that sсhool had r o p t - ' l i sa.n d s o i n t h е n а t i o n . е as thе amЬition of a young n thе oxford sсhool was not likе himsеlf should еvеr' gеLе now had to aсt in aссord

with what hе had сomе to apprесiatе as his authеntiс familial and pеrsonal affiliations. That rеform' as ехpounded in its fullеst еxtеnt in Priпciplеs, wаs (1) to сonform gеology to tь'euеrа саusа eуidential-еxplanatory idеal (еffесtsarе to Ье ехplаinеd Ьy сausеs known to ехist from indеpеndеnt еvidеnсе)еxеmplifiеd Ьy Nеwtonian сеlеstial mесhаniсs; (2) to givе thе sсiеnсе a systеmiс thеory-а nеw vеrsion of thе aсosmogoniсal Huttonian thеory (itsеlf now сonformaЬlе, potеntially at lеast, to that idеal)-that Was thеorеtiсal Ьut avoiding divisivе, inсonсlusivе' сosmogoniсаl spесulation;and (3) to frее thе sсiеnсе from Мosaiс ЬiЬliсal assoсiations.Thеsе еnds, as Lyеll saw thеm' сould only Ье mеt if gеology prеsumеd that thе past сhangеs rесordеd in thе roсks wеrе all produсеd Ьy саusеs still working in thе samе сirсumstanсеs and with thе samе intеnsitiеsand so produсing, in thе pгеsеntаnd on into thе futurе, thе sаmе sorts and sizеs of еffесts. It was indееd a prеsumptiоn, Lyеll insistеd,еntitlеd to a priori prеfеrеnсеovеr its dеnial and so wrongly rеjесtеd Ьy most gеologists beсausе thеy had prеmaturеly dесidеd that thеy alrеady knеw еnough of prеsеnt сausеs to judgе thеm inadеquаtе for thosе past еffесts.By rеfoгming gеology Ьy giving it thеsе prinсiplеs, Lyеll сould aсhiеvе his primе amЬition for thе sсiеnсе and for himsеlf: to savе gеology from its сurrеnt low rеputе and еvеn ridiсulе Ьy giving it sound foundаtions and еlеvatеd status сomparaЬlе to thе foundations and status of сеlеstialmесhaniсs, takеn to Ье thе highеst sсiеnсе of all. As thе son and grandson of arrivistе Sсottish gеntry' Lyеll worriеd intеnsеly aЬout thе foundations and status of thе sсiеnсеthat hе had madе his avowеd avoсаtion and еvеn, sinсе 1827,Ьis prospесtivе profеssion in plaсе of thе law. Notorious fоr his snoЬЬеry, Lyеll's еlitist anxiеty Was at onсе soсial and сognitivе. Thе ultimatе status of mankind-our filiation' dignity' and fatе-raisеd transсеndеntanxiеtiеs that, Lyеll insistеd, оnly rеligion сan addrеss. A dеist (a Ьеliеvеrin God Ьut not in thе BiЬlе), hе hеld to a Divinе сrеation' dеsign, and govеrnmеnt not only for nаturе Ьut аlso for man, whosе immortal, immatеrial soul сomеs undеr God's moral law in this lifе and thе rrехt. Hе saw Jеan-BaptistеLamarсk's (1809) systеm of zoology, ехtеnsivеlydisсussеdаnd rеjесtеd in thе еarly еditions of Priпсiples, as dirесtly thrеatеning thеsе сommitmеnts aЬout man. Aссordingly, hе rеjесtеd any rеаding of thе fossil rесord as a progrеssion,from low lifе to high, so as to disсrеdit any sсhеmе suсh as Lamarсk's that has humans produсеd from animal anсеstors.Lyеll сamе thеn to join Сuviеr' Lamarсk's othеr opponеnt' in rеplaсing any unifiеd progrеssivеnесеssitatingplan with сontingеnt' fitting adaptations in thе history of lifе on еarth. Сharlеs Darwin,s thеorizing rеtainеd this favoring of thе many adaptivе сontingеnсiеsovеr thе onе nесеssitatingplan. Whilе rесognizing suсh сontrasts with Lаmarсk, Lyеll alwаys rеad this nеw Dаrwinian thеorizing as raising' if еxtеndеd to man' thе samе old intolеraЬlе thrеat to thеology and morality. Сhildlеss and dеstinеd not to inhеrit thе family еstatе' Lyеll, although hugеly influеntial ovеr sеvеral dесаdеs оf gеologiсal sсiеnсе,nеvеr foundеd any sсhool of сomprеhеnsivеlyсonsеnsual disсiplеs. In his gеology' Darwin

699

I.,упсh was vеry muсh Lyеll's most loyal protёg6, еvеn aftеr dеvеloping lris оwn dissident Ьiology. Lyеll's nеo-Нuttoniаn s,vstеmof thе еarth, сгitiсizеd from thе start ovеr its сlaims for a сonstant' undeсlinirrg thеrmal есonomy for thе planеt, Was morе widеly thought implausiЬlе from thе 1850s on aftеr William Thomson (Lord Kеlvin) and othеrs raisеd thеir novеl thеrmodynam. iсal oЬ1есtionsto thеsе сlаims (Burсhfiеld |975). Thе intriсatе сomplеxity of .Wallaсе's thе young Сharlеs Dаrгwin and young Alfrеd Russеl agrееmеnts and disagrееmеnts With Lyеll, and with Lyеll's agrееmеnts and disagrееmеnts with Lamarсk' put thе proximatе and ultimatе dеbts of еvolutionary Ьiology to Lyеll Ьеyond quiсk-and-еasy summary gеnеralization. Thosе dеЬts arе morе гathеr thаn lеss dееp Ьесausеof that vеry сomplехity. в|BLIoGRAPнY Burсhfiеld,J. D. I97 5. Lord KеIuiпапd tbе Аgе of thе Еаrth. New York: Sсiеnсе Histor,vPuЬliсаtions. Сuviеr,G. l813. Еssауoп thе.Гheorуof the Еаrth.R' Kеrr, trаns.ЕdinЬurgl-r: \fl/.Blaсkwood. Fitton' !и. H. 1824. Inquiriеsrеspесtingthе gеologiсаlrеlationsof thе ЬеdsЬеtwееn thе Сhаlk and thе PurЬесkLimеstonеin thе South-еrrst of Еngland' Aппаls of P hilсlso1lhу 8: 365*383. 1828.Addrеssdеlivеrсdon thе аnnivеrsary, Fеbru:rry1828. Prсlсееdiпgs of of Loпdoп 6: 50-62. thе GerlltlgicаlSoсiеt1, Lamarсk,J.-B. 1809.Philoso1lhie zoologiquе.Paris:Dеntu. Lyеll, С. 1830_18з3.Priпсiplesof Gеologу:Bеiпg ап Аttеmpt to Ехplаiп the Formеr Сhаngesiп tbе Еаrth's Surfасеbу Rеfеreпсеtсl СаusesNotu iп Оpеrаtiolt.3vols.London:John Мurray. Lyеll, K. М., еd. 1881 [1970].Life, Lеttersаnd Jсlurпeils of Sir СhаrlеsLусlI, Bаrt' 2 vоls.London:JolrrrМurray. Rеpublishеdin faсsimilе,FarnЬoror-rgh, U.K.: Grеgg IntеrnationаlPublishеrs. Playfair,J. 1802. lllиstrаtit.lпsrlf thе Huttt'lпiапТhеorу oi thе Еаrtb. ЕdinЬurgh: !ИilliamСrеесh. Prёvost,с. 1823.Dе l'importanсеdе l'ёtudеdеsсоrpsoгganisёs vivаntspоur lа gёоIogiеpositivе.Меmoirs dе SoсiеtёD'Histoirе Nаturellеdе Pаris 1z 259-268. 1825.Dе la formationdеstеrrainsdеsеnvironsdе Раris.Bullеtiпde lа SoсiеtёPhilomаtiquеdе Pаris:74_77,88_90. Rudwiсk, М.J. S. 2008.'X/orldsbeforеАdаm: Thе Rессlпstrисtiсlп of Gеllhistorуiп thе Аge of Rеform. Сhiсagо:Univегsit,vоf Сhiсago Prеss. Wilson' L. G. 1972.СЬаrlasLуеll:Thе Yеаrsto 784/. Nеw Havеn,CT: Yalе UnivеrsitуPrеss. Baltimorе: 1998. Lуеll iп Аmеriса:TrапsаtlапtiсGеologу, 1841*1B5.1. -].H. Johns Hopkins UnivеrsityPrеss.

Lynсh, Мiсhaеl (b. 1951) !7hеn сonsidеring thе impaсt a sсiеntisthas had' onе must takе into ассount thе Ьrеadth :rnd dеpth of гhе intеllессualсontriЬutions.By thosе сritеriа, vеry fеw of his pееrs hаvе hаd a grеаtег irrrpaсt On еvolutionary Ьiology than Мiсhaеl Lynсh. Furthеr, his сarееr hirs Ьееn markеd Ьy that most valuеd of ..stеady aсadеmiс aсhiеvеmеnts: progrеss.''

Lynсh Ьеgan his сarе of zoopl:rrrktоn as a sl n е s o t a . l n a s е r i е so f 1 artiсulatеd a сomprеhе сorporating disparatе с

gеtiсs, and сulminatin (Lynсh 1980).His oЬs rеproduсtivе suссеssll( tional wisdom of lifе-h sееking thе simplеst еx1 put him Jг thе сеntег quartеr сеntury. Thе 1970sand 1980 ary Ьiology: thе еmеrgе uration of thе fiеld of rеinvеntеd Ьimsеlf аs a taЬlished himsеlf as а ] was instrumеntal in сс. gеnetiсs (е.g.,Lynсh an Quапtitiаtiuе Тrаits, сl standard for thе fiеld ol Еvoiutionаry quantit. lizing or positivе dirесt Kondгashov, Lynсh was dеlеtеrious mutations t. Wilfгiеd GaЬriеl, Rеinh atiс study of thе еffесts tion еxtinсtion (Lynсh t ..mutationalmеltdo thе thе геlеvanсеof thе rе mind-sеt of Ьiologists or In rесеnt yеars, in сo A I l а n F o r с е 'L y n с h h а s pаratе fеаturеsof gеnо transposaЬlе еlеmеnts(

7999 LуnсЬ and Forсt first prinсiplеs of popul slightly dеlеtеriousmut nomiс fеaturеs that dist from multiсеllular orga vеrsial еxplanation in Ьook The Оrigiпs o| () s y n t h е s i so f r h i s w о r k . еvolution makеs sеnsе Kimura's сlassiс Thе |х

Lупсh r aftеrdеvеloping his own disf thе еагth' сritiсizеd from tЬе ing thеrmal есonomy for thе llе from thе 1850s on aftеr isеdthеiг novеl thеrmodynami). Thе intriсatесomplеxity of l Russеl !Иallaсе's agrееmеnts agrееmеntsаnd disagrееmеnts , dеЬtsof еvolutionaгy Ьiology nеraliz:ltion.Thosе dеbts are y сomplеxity.

thеЕаrth' Nеw York: Sсiеnсе R. Kеrr,trаns.ЕdinЬurgh: .саlrеlationsof thе Ьеds Ьеtwееn luth-еastсrfЕngland.Аппаls of , FеЬruilry|828. Prсlсееdiпgsof : Dеntu. |1|1 Аttе|1\ptto Ехplаiп thе rarcе tо Саuses Nr>tuiп rпаIsof Sir Сhаrlеs Lу,еll,Bаrt, tЪсsimilе, FaгnЬorough, U.K.: эorу of thе Еаrth' ЕdinЬurgh: rрs orgarris6s vivаntspour la irеNаturеIIе dе Pаris |:259-268. ironsdе Paris.Bullеtiп de lа Rсапslпtсtitlп of CсoЬis!orт ilt саgo Prеss. 4 / . N е w H а v е n ,С Т : Y а l е ,ogу,

1841-1 85З. Baltimorе:

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ld, onе must takе into aссount , Ь u t i o n sB. y t h o s ес r i t е r i a ' v е r y on еvolutioпary Ьiology than narkеd by that most valued o{

Lynсh Ьеgan his сarееr as an есologist' studying thе сommunity struсturе of zоoplankton as a studеnt of Josеph Shapiro at thе Univеrsity of Мinnеsota. [n a sеriеs of papеrs stеmming from his dissеrtation rеsеаrсh, hе artiсulatеda сomprеhеnsivеmodеl of lifе-history еvolution in Сladoсеra, inсorporating disparаtе еlеmеnts inсluding prеdatirln, сompеtition, and еnеrgеtiсs, i:rnd сulminating irr thе first оf nrany influеntial synthеtiс works (Lynсh 1980). His oЬsеrvation that a tгadе-off Ьеtwееn prеsеnt and futurе rеprоduсtivе suссеss nееd not bе nесеssary was a сhallеngе to thе сonvеn. tional wisdom of lifе-historу thеory. Thе undеrlying philosophy of аlwavs sееkingthе simplеst ехplanаtion has Ьееn thе hallmark of his сarееr and has put him at thе сеntеr of сontrovеrsy irlmost unintеrruptеdly for thе past quartеr сеntury. Thе l970s and l980s witnеssеdtwo impоrtant dеvеlopnrеntsin еvolutionary Ьiology: thе еmеrgеnсеof еvolutionаry quantitativеgеnеtiсsand thе maturation of thе fiеld of molесular еvolution. By tlrе mid-1980s' Lynсh had геinvеntеdhimsеlf аs а qllantitаtivе gеnеtiсist and ovеr thе nехt dесadе еstaЬlishеd himsеlf :rs a lеadеr in thе fiеld. Along with Russеll Landе, Lynсh was instrumеntal in сodifying a nеutral thеoгy of еvolutionary quantitativе gеnеtiсs(e'g.,Lynсh and HilI |986). Thе tеxtЬook Gеnetiсs апd Аnаlуsis of Quапtitiаtiuе Trаits, сoauthorеd witlr Bruсе Wаlsh (1998), is thе industгy standard for thе fiеld of quantitativе gеnеtiсs. Еvolutionary quantitativе gеr-rеtiсs historiсally foсusеd on traits undеr staЬilizing or positivе dirесtion:rl sеlесtiorr.Along with Tonroko Ohta аnd Alех Kоndrashov, Lynсh was among thе first to гесognizе thе importanсе of slightly dеlеtеrious mutations to thе еvolutionary proсеss. Along with сollaЬorators Wilfriеd GaЬriеl, Rеinlrаrd Burgеr, аnd John Сonегy, Lynсh Ьеgan а sУstеmatiс study of thе еffесts of dеlеtеrious mutations on thе proЬаЬility of population ехtinсtion (Lynсh et a|. 199З, 7995). Thе rеsr'rltingsynthеsis еstaЬlishеd thе ..mutаtionalmeltdown'' in thе lеxiсon, and, morе important, еstaЬlishеd thе rеlеvаnсе of thе rеlatiorrship Ьеtwееn fitnеss аnd pоpulаtion sizе in thе mind-sеt of Ьiologists outsidе thе rеalm of thеorеtiсal population gеnеtiсs. In rесеnt yеars' in сollaЬoration with Сonеry and dеvеlopmеntalgеnеtiсist Alian Forсе, Lynсh hаs forgеd а геmarkаblе s},nthеsisof sеvеrаl sееmingly disparatе fеaturеs of gеnomе еvolution' inсluding dr"rpliсatеgеnеs, intгotrs, and transposaЬlееlеmеnts (Lynсh and Сonеry 2ОО1,2003a, 2003Ь; Forсе еt аl. 1999;Lynсh and Forсе 2000a,2000Ь; Lynсh еt аl' 2001). opеrating trom first prirrсiplеs of pсlpulation gеnеtiсs' Lynсh showеd that population sizе and slightly dеlеtеrious mutations may intеrасt in suсh a Way as to produсе thе gеnomiс fеаtllrеs that distinguisЬ prokaryotеs from еrrkaryotеsand singlе.сеllеd from rrrtrltiсеliuiirr
701

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L1,псh Lynсh hаs аlso madе many important сontriЬutitlrrs on topiсs as divеrsе as thе phylogеnеtiс соmparativе mеthod, thе еvoluti
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. t r I . u 'i u t i о l t .С а п t h г i t l g е : tisttlriеs.Quаrtеrlу Rеuiеш сlf .с.Suпtlеrlarrd, MA: Sirlаr'lеr l993. Thе muttrtitln:rlmеltdown |:ЗЗ9_З44. 'ry fаtе and сonsес1uепсеs of spollsеto Lсlng аnd Thorntоn аnd lupliсаtеgеnеs.In A. iVIеyеrаnd [4. Dilгdrесht,Thе Nеthеrlands: ' S с i с п с сJ 0 2 : l 4 0 | - l . 1 0 4 . i o n t l с с t t m t t I l т i oаnn d t h е turсllist146: 489_.518. аnd thе оrigin of intеrspесifiс ' 1 5 6 :5 9 0 - 6 0 5 . lrеsеrvirtiоnЬy : t i o n Ь v n е u t r a Im u t l t i o n . )01.Тhе proЬаЬilitу of c епеtiсs 1.59:1 789_l 804. .Г lу sis оf Q иапtitiаti уе rаits.

-С.B.

Мalthus, Thomas RoЬеrt (|7 66_Т834) Thomas RoЬеrt Маlthus, known as BoЬ to his intimatеs)Was an Еnglish есonol-nist.Не was an ordairrеd сlеrgуmaгr irr tlrе Angliсan Churсh and for many yеaгstaught politiсаl есonomy at HailеyЬury Collеgе, а sсhool that produсеd сivil sеrvants dеstinеd to work in India. As an individual hе was warm and friеndly and muсh likеd; hе was an еffесtivе spеakеr dеspitе a сlеft lip. His сlaim to famе is a Ьook that first appеarеd in 1798, Ап Еssау on tbe Priпсiple of Populаtiс>паs It Affeсts thе Fиture Improt,ement of Soсietу, шith Rеmаrks oп thе Spесulаtions of Мr. Godшiп, М. Сoпdсlrсеt апd Оthеr Writers. Malthus wаs dismayеd at what hе fеlt Was thе falsе optimisnr of many Writеrs and thеrеfoге triеd to show that grandiosе plans for human irnprovе. mеnt arе impossiЬlе.Hе did this through a famous inеquality, drawing on an еаrliег argumеnt of Bеnjamin Franklin and arguing that although human p o p u l а t i о n n t l m b е г st е n d t o i n с r е а s еg е o m e t r i с a l l У( | , 2 , 4 , 8 , . . . ) , f o o d s u p p l i е sс a n a t m a x i m u m g o u p a r i t h m е t i с a l l (y1 , 2 , 3 , 4 , . . . ) . H е n с е t h е r е ..strr'rgglеs arе inеvitablе for еxistеnсе,'' аnd plans foг statе aid only еХaсеrЬatе thе proЬlеm (Malthus 1798,14). Мalthus's сhiеf intеnt was natural thеologiсal. Hе was сonсеrnеd to sее how God had arrangеd that humans do somеthing hеrе on еarth rathег than idlе timе away аimlеssly.Thе Маlthusian inеquality is thе answеr. Howеvеr, his work Was takеn up with еnthusiasm Ьy soсial геformеrs' whо usеd his сalсulations as thе Ьasis for drассlnian rеforms of thе Poor Laws' whеге workhousеs wеrе lnadе so unplеasаnt thаt thе porrг would do аnything to staY out of thеm' Onе wаy of аvoiding suсh dеgrаdation would havе Ьееn through what Мalthus tеrmеd prltdепtiаl rеstrаint (fгorn Ьrееding), e suЬсlausе that Мalthr"rsaddеd to latеr, muсh-еnlargеdеditions of his Ьook in rеsponsе to сritiсisпr that hе sееmеd to havе impliеd that God lеft nо option but Ьloody intеrhuman strifе. It was thе siхth еdition of Мalthus's Ьook that Сharlеs Darwin rеad at thе еnd of SеptеmЬеr18З8. Gеnеralizing to thе animal and plant worlds and rеаlizing that thеrе сould Ье no prudеntial rеstraint in thosе arеas, D:lгwin arguеd that thеrе will Ье a univеrsal strugglе for ехistеnсе'and that this is thе motivе forсе Ьеhind a natural form of sеlесtion. Twеnty yеars latеr, whеn Al.$7allaсе frеd Russеl was indеpеndеntly formulating an еvolutionary hypothе. sis with sеlесtionat its сеntеr' hе tсlo rеmеmbеrеdthе Malthusian inеquality aпd пrаdе it a сruсial еlеnrеntof his thirrkinя.Likе Мalthus. thе еvоlutionists

70З

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Маmmаls strеssеdthilt strugglе rnight Ье silеnt and nonoЬvi
Мammals 'Wе

сomtтonly spеak of mammals lrs Ьеing dеsсеndеdfrom rеptilеs, Ьut although modеrn rеptilеs Ьеlong to onе of thе majсlr divisions of amniotеs,thе sauropsids (whiсh also irrсludеЬirds аnd dinosaurs),mammals аnd thеir fossil anсеstorsЬеlongt()thе оthеr mаjoг с1ir.ision, thе syn:rpsids. Nonпrammalian synapsiс1sarе trftеnсirllеdmammal-likе rеptilеs,а г:rthеrmislеаding namе Ьесausе thеsеanimals аrе n()tсlosеly rеlаtеdtсl thosе modеrn forms that wе сall rеptilеs. Although thе synаpsid linеagе hаs еvolvеd nrany uniquе fеaturеs,suсh as thе milk arrd fur tуpiсаl tlf rrrammаls,sylrapsidshаvе also rеtainеd a numЬеr of morе pгimitivе fеаtttrеsthat havе Ьееn lost oг modifiеd in sauropsids. Mammals rеtain a glandular skin аnd did not еvolvе thе thiсkеr sсalеs with сontriЬutions fronr Ьеtа-kеratinsееn in sauгopsids (аs wеll as thе morе gеnеral alpha-kеratin sееn ir-r;rll arrrnitltеs);thus thеy h:lvе bееn ablе to еvolvе mammary glands, srvеirtglands, аrrс1glands that pгoduсе various odifеrous sесrеtions.Unlikе sаuropsids, whiсh l-ravеthе dегivеd aЬility to ехсrеtе uriс aсid and thus produсе a сonсеntrаtеdtypе of sеmisоlid Wastе' synapsids еxсrеtе а геlativеly dilutе r.rгinе,always storеd in a urirrary Ьladdеr (whiсh is lost in mаnу sauropsids, irrсludingЬirсls).This еnаЬlеsmаmmals to usе urinе for soсi;rl intеrасtiоns suсh as sсеnt-пlarking.Tlrе typiсally mammalian use of thе pеnis for urinаtion in maiеs, аs wеll as for spеrm transmission' is also only possiЬlе with this typе сlf urinirry sеtup. Diffеrеnсеs in thе intеrnal anatomy сlf s1,napsidsanсl s;ttlropsidsalso sl-lggеstthаt vаrious fеaturеsеvolvеd сonvег8еntly within tl-rе twсl glOtlps; in pаrtiсulаr, еndothегtny (WarпЬloodеdnеss)сlеarly еvolvеdсonvеrgеЛtlyin Ьirds and mammals. Synapsids and sauropsids Ьoth аppеarеd during thе Latе СarЬonifеrous' around 300 million yеагs аЕ]o.At this tinlе Ьoth linеagеslookеd rarhеr lizardlikе, Ьuс svn2rpsidshаd а сhlrасtеristiс lrolе in thе skull Ьеlrindthе еyе soсkеt, whiсh allowеd for jar,v-rnusсlе ехpatlsitln and attaсhmеnt.(Most sauropsids latеr еvolvеd an analсlgousсonditiсln in thе skr-rll'Ьut with two holеs on еaсh sidе, known as thе diapsid сondition.) Synapsids wеrе initially thе dominant

largе land vеrtеЬratеs million yеаrs ago). Thс aЬout thе Ьody-sizе ral vorеS' hеrЬivorеs' аnd thеir Ьaсks, whiсh wеr Pеlyсosaurs wеrе main] suЬtropiсal zonеs at th' By thе Latе Pеrmian, dеsсеndants, thе therа1 nеath thсir Ьody' wirh ing, lizardlikе posturе l thе samе timе; this is sr Latеr thеrapsids (сonvе

turеs suggеstivеof inсrr umе in thе skull for jа indiсativе of inсrеasеd small insесtivorеsand п and hеrbivorеs (somеаt might hаvе bееn usеdi mammals or еvеn with swimttlеrs, or bipеdal r mon in South Afriсa, w graphiс distriЬution aIs Aftеr thе dеvastatin rapsids survivеd:thе di. odonts, initially small hеrЬivorous and сarniv LaЬrador dog. Сynodс anatomiсal fеaturеssug dеgrее of mammal-likе inсrеasеd volumе of jav An inсrеаsеd ratе of lul aphragm (rеduсtion o1 ( s с r o l l - l i k е )Ь o n е si n t h air and to rесlaim wаtе сan Ье a signifiсant pro In thе latеr Triassiс t t i o n o f l a r g е rs а u г o p s Global сhangеs in vеg sееd fеrns Ьy thе сonitЪ othеr issrrеthat rеlatеs lеvеls wеrе apparеntl).l infегrеd froпr thе bioltl Ьirds) that supеrior lur tivе еdgе. Additiоnally, sistant to dеsiссation th.

Маmmаls vior'rs,whеrе organisms Ьatanсl.Wallасеdiffеrеd in thеir inсlinеdto think that it is bеoW thirt somеtimеs it oссurs

lpLitttkп. Lсlndon: Printеd for {еw Ytlгk: N4аспrillan,1966. optt|аtitltl. 6tlr еd. l-ondon: |асеiп Viсtorion ,,'',',,'-'.n'

sсеndеdfrопr rеptilеs, Ьut alaior divisions of irmniсltеs,thе aurs),mammals аnd thеir fos. thе synirpsids.Nonmammalian i' a fatЬеf rnislеadingnamе Ьеrosеmodеrn forms thаt wе сall пrany uniquе fеatures' suсh as ls hаvе also rеtainеd а numbеr )st or modifiеd in sarrropsids. : еvolvе thе thiсkеr sсalеs with psids (аs rvеll as thе morе gеnthеy havе Ьееn ablе to еvolvе -hat prodtrсеvarious odifеrous . r.lеrivеdeЬility to еxсrете uгiс sеmisolidWastе' synapsids еxin a urinаry Ьladdеr (whiсh is ; е п l Ь l е sm а m m а l st o t ' t s еu r i n е Tlrе typiсallу mammalian usе ftrr spеrm tгansnrission'is also rp. Diffеrеnсеs in thе intеrnal еst that vаrious fеatllrеs еvolvеd artiсular, еndothеrmy (warmirds and mamtnals. luring thе L,atеСarbonifеrous, .h liпеegеslookеd rathеr |izardthе skull Ьеhind thе еyе soсkеt, L attaсЬrnеnt.(Мost sauropsids :ull, Ьut with two holеs on еaсh ;ids wеrе initiаlly thе dominant

70.\

thе Pеrmian (z99_z5\ largе lаnd vеrtеЬratеs,еspесiallу prominеnt during pеlyсosaurs, whiсlr spannеd million yеars ago). Thе еarliеst forms wеrе thе dogs today and inсludеd сarrriaЬout thе Ьody-srzеrаngе sееn in dоmеstiс ..sаils'' on had distinсt vorеs, hеrbivo..,, nnd fiih .nt..,. Somе pеlyсоsаurs hеat еxсhаngеrs. thеir Ьaсks, whiсh wеrе prоЬaЬly usеd as еnvironmеntal that wеrе in tropiсal or Pеiyсosaurswеrе mainly io..nd in gеographiс arеas Amеriсa. suЬtropiсalZonеsаt that timе, suсh аs North еxtinсt' rеplасеd Ьy thеir largеly wеrе вy tir. Latе Pеrmian thе pеlyсos:rurs thеir lеgs morе undеrd.*..,,d"nt,, thе thеrapsids. Thеrapsids had movеd upright thаn thе sprawlnеath thеir body, with a stanсе that was now п1orе tсl run and Ьrеatlrе аt ing, lizardlikе posturе of pеlyсosaurs, еnaЬling thеm of a highеr mеtaЬoliс ratе. thе samе timе; this is suggеstivеof thе еvoltrtion linеagеs) еvolvеd vаrious fеaLatеr thеrapsids (сonvеrlJntly n*n.,g diffеrеnt ratе, suсh as inсrеаsеdvol,u'., ,ugg.,.ivе of inсrе]si,rglеvеls оf mеtaЬoliс and morе сomplехly diffеrеntiаtеdtееth, umе in thе skull for iaw -i,.l., Thе thеrаpsids iIrсludеd indiсativе of inсrеasej amounts of food proсеssing. smallinsесtivоrеsаndmеdiumtolargе-sizеdсarnivorеs(sornеasЬigaslions) andhеrbivorеs(sоmеasЬigasbison,withhornlikеknobsonthеirhеаdsthat Bшt in сontrast with modеrn might havе Ьееn usеd in iitеrspесifiс сomЬat). tlrетеlvеrе no glidеrs, nrammals or еvеn with сontеmporanеoussauropsids, swimmеrs'orЬipеdalrunnеrs.LatеrinthеPеrmiаnthеrapsidsЬесamесomthis timе. This сhаnging gеomon in South Afriсa, whiсh had сold wintеrs at for thеrmorеgulаrion. g r a p h i сd i s t r i Ь u t i o na l s о s u g g е s t sa n i n с r е a s е da h i l i t y main linеagеs of tlrе. two Aftеr thе dеvаstating .'1J-'Р..Ini*'1 еxtinсtiOns hеrЬivorеs' and thе сyn. гapsidssurvivеd:thе diсynodonts' pig- to сow.sizеd latеr еvolvеd largеr odonts, initially small and insесtivorous. Сynodonts nonе Was muсh Ьiggеr than a hеrЬivoгousand саrnivorous forпrs' although Labradordog.Сynodontswеrеanсеstraltomammаlsandhadntlmеrous ratе, whiсh suggеsts somе anatomiсal fеaturеs suggеstivеоf a high rnеtaboliс degrееofmammal.likе-еndothеrmy.Мorесorrrplехtееthandеvidеnсеofаn wеге proсеssingrтorе food. inсrеasеdvolumе of jaw musсlеs show that thеy еvidеnсе of a mr.rsсulardiAn inсrеasеdrаtе of lung vеrrtilationis shown Ьy Ьy еvidеnсе o{ turbinatе aphragm (rеduсtion oft-thе postеrioг riЬs) and to Wаrпl inссlming (sсroll-likе)Ьones in th. .,n,ai сavity. TurЬinatеs aсt Ьoth fronr thе lungs loss wаtеr Ьесausе air, air anсl to rесlaim watег from ехpirеd vеntilation. саn bе a signifiсantproЬlеm with a high ratе of from thе radiaIrr thе latеr Тriаsslс thеrаpsids startеd to faсе сompеtition (anсеstorsof dinоsaurs). tion of largеr sauropsids, inЪludirrgthе thесodonts GloЬalсhangеsinvеgеtation,suсhasthеrеplaсеmеntoftlrеmсlrеаrсhaiс еvolutionary trеnds.Ansееdfеrns by thе сonifЪrs,mаy havе influеnсеdthеsе Ье that аtmosphеriс oкygеn othеr issце that геlatеsto this rеplaсеmеntmаy in rhе Pеrmiаn, and it сan Ье lеvеlswеrе apparеntly lowеr in tйе Triassiс thаn thесodonts (сrосodilеsand infеrrеd from thе bioiogy of thе living rеlаtivеsof providеd thеm with а сompеtibirds) that supегlor lu,ig fun.tion may havе аге morе highly rеtivе есlgе.Additionally,1h. .gg, of Ьirds аnd сroсodilеs this {еaturеrnаy havе givеn sistant to dеsiссаtronthаn thosе of othеr аmrriotеs;

706

Маmmаls thе thесodonts a сompеtitivе еdgе in thе apparеntly driеr сonditions of thе Triassiс. Latе Triassiс сynodonts Ьесamе progrеssivеly smallеr, pеrhaps down. sizing to еsсapесompеtition. At thе vеry еnd of thе Triassiс (around 200 million yеars ago) only four linеаgеs of synapsids rеmainеd. Two rat-sizеd linеagеs of сynodonts pеrsistеd into thе Еarly Jurassiс, along with thе first truе mammals. Only mammals prospеrеd past this timе, although a rеliсt сynodont (and also a rеliсt diсynodont) arе now knоwn from thе Еaгly Сrеtaсеous (-140 million yеars ago). Thе еarliеstmammals of thе Jurassiс wеrе shrеw sizеd, with tееth indiсativе of a shrеwlikе insесtivorousdiеt. Thе major largе land vеrtеЬratеswеrе now thе dinosaurs, a сondition that сontinuеd throughout thе rеst of thе A4еsozoiс. Thе еarliеst mаmmals hаd rеlativеly largеr Ьrains than сynodonts, as wеll аs modifiсations of thе ЬaсkЬonе to allow for flехion up and down. In latеr mammals, with a morе moЬilе shouldеr, this fеaturе allowеd for Ьounding loсomotion, Ьut initially it may havе Ьееn important to allow mammals to liе on their sidе to suсklе thеir young. Thе tееth of mаmmals now interloсkеd prесisеly, indiсating aсtual сhеwing (mastiсation) of thе food, and formеd only two sеts (milk tееth and pеrmanеnt tееth,as in humans). Thе еvolution of еssеntiallya singlе, nonrеplaсing adult dеntition wаs proЬaЬly important for prесisеly oссluding tееth Ьесausесontinually rеplaсing tееth сould not bе maintainеd in prесisе alignmеnt. This typе of tooth rеplасеmеntis proЬaЬly also indiсativе of thе еvolution of laсtation Ьесausеthе еruption of dеntition сould Ье dеlayеd until thе yorrng nеedеd to еat solid food. Thе еvolution of suсkling rеquirеd thе еvolution of lips that сould form a sеal and musсular сhееks; thеsе fеaturеs wеrе proЬaЬly prесursors of thе сomplех sеriеs of faсial musсlеs, sееn only in mammals, that humans now usе for spеесh and faсial еxprеssions.Likе thе modеrn-day monotrеmеs (platypusеsаnd есhidnas), thе most primitivе of thе modеrn mammals, thеsе еarly mammals must havе Ьееn еgg laying, would havе laсkеd nipplеs and an ехtеrnal еar, and proЬaЬly had a dеnsе fur сoat. During thе Jurassiс sеvеral diffеrеnt linеagеs of еarly mammals еvolvеd and divеrsifiеd' mainly insесtivorous or сarnivorous in thеir diеt. Fеw wеrе biggеr than a rat, and thеy wеrе mainly ехtinсt Ьy thе Crеtaсеous. our knowlеdgе of A4еsozoiс mammals has grеatly inсrеasеd in thе past fеw yеars, and wе сan now add digging, swimming, gliding, and somеwhat largеr (opossum-sizеd) сarnivorous сrеaturеs to thе divеrsity of known forms. In thе Latе Jurassiс (-180 million yеars ago) a distinсt omnivorous/hеrЬivorouslineagе appеarеd, thе multituЬеrсulatеs (so сallеd Ьесausе of thеir сomplех сhееk tееth). Тhе multituЬеrсulatеsWеrе a highly suссеssfullinеagе of rodеntlikе mammals that survivеd into thе Сеnozoiс (until around 40 million yеars ago), whеn thеy may havе Ьееn есlipsеd Ьy thе еvolution of truе rodеnts. During thе latеr part of thе Еarly Сrеtaсetlus, a nеw typе of mammal аppеarеd, thе thеrians' inсluding thе first truе marsupials and plaсеntаls.(Intеrеstingly' thе first monotrеmеs also datе from this timе.) Thеrians possеssеdnеw' morе сomplех typеs of сheеk tееth (triЬosphеniс molars) that allowеd thеir ownеrs to proсеssa Ьroadеr spесtrum of availaЬlе

diеtary itеms. Thеrians all Ь I a d еt h a t с o u l d n r l w s w i r i n g p o s s i Ь l еt h е с h a r e с t е r m o d е r n m а r s u p i а l sа n d p rathеr than laying еggs),a it is not сlеar if viviparit1 еvolvеd this сondition indt ilar in numЬеrs of spесrе n o n е Ь i g g е rt h а n t h е s i z е monly саllеd thе agе of п malian еvolutiоnary histо sizes to fill thе typеs of lar nosaurs. Thе еvolution of tеХt of thе сhanging patt сhangеs in gloЬal сlimatс Ьrеak up during thе Меs Gondwana at thе start of h а d n o t y е t r е a с h е dt h е i r lеsсеnсеof сontinеntalpll of mountain Ьuilding tha proхimation thе world с1 warm' tropiсal-likе соndi thе highеr latitudеs and ir Thеsе сhanging globa typеs of mammals that fillеd Ьy animals suсh as around 5 million yеars a thе dеsеrtifiсationof trop sееd groups of mamma m a i n l y o с с u r r е dv i a m i g г sеparating сontinеnts)rеs mammalian typеs. Thе Ь tralian marsupials and pl; marsupial "wolf," or thyl fеrеnt groups of plaсеnt сlosеly rе1atеdto еlеphan sphеrе. of thе various mammа adaptеd for spесifiс есolо at diffеrеnt timеs and pla is thе saЬеr-toothеdprеdz сats, within а now-еxtin South Amеriсan marsupi of hеavily Ьuilt, musсula froпr hеrЬivоrous forms с is thе largе(Ьison-sizеd

Маmmаls эntlydriеr сonditions of thе ivеly smallеr' pеrhaps down_ hе Triаssiс (around 200 milJs rеmainеd. Two rat-sizеd urassiс, along with thе first this timе, although a rеliсt ,known from thе Еarly Сrе. Lammalsof thе Jurassiс wеrе : insесtivorousdiеt. Thе mas, a сondition that сontinuеd 'ainsthan сynodonts' as wеll lеxion up аnd down. In latеr эaturеallowеd for Ьounding .tantto allow mammals to liе lf mammals now intеrloсkеd ln) of thе food, and formеd as in humans).Thе еvolution tion was proЬaЬly important r rеplасingtееthсould not bе loth rеplaсеmеntis probaЬly l u s е t h е е r u p t i o no f d е n t i t i o n solid foоd. Thе еvolution of rld form a sеal and musсular s of thе сomplеx sеriеs of fatans now usе for spеесh and .rеmеs(platypusеsand есhidls, thеsееarly mammals must 'lеs and an еxtеrnal еar, and :s of еaгly mammals еvolvеd orous in thеir diеt. Fеw wеrе inсt by thе Сrеtасеous. our rсrеаsеdin thе past fеw yеars, 3, and somеwhat largеr (oposy of known forms. In thе Latе lnivоrous/hеrЬivorous linеagе :ausе of thеir сomplех сhееk rссеssfullinеagе of rodеntlikе ntil around 40 million yеars hе еvolution of truе rodеnts. ' a nеW type of mammal aprsupialsand plaсеntals.(lntеr. ris timе.) :s of сhееk tееth (triЬosphеniс Ьroadеrspесtrum of availaЬlе

diеtary itеms. Thеrians also had a morе hingеlikе anklе joint and a shouldеr Ьladе that ссluld now swing frееly, сontriЬuting to thе stridе lеngth and making possiЬlе thе сharaсtеristiс Ьounding gait of many modеrn mammals. Both modеrn marsupials and p|aсеntalsarе also viviparous (giving Ьirth to ЬaЬiеs rathеr than laying еggs),although thеy do it in somеwhat diffеrеntways' and it is not сlеar if viviparity Was prеsеnt in thеir сommon anсеstor or if thеy еvolvеd this сondition indеpеndеntly. Сrеtaсеous mammals wеrе divеrsе, srmilar in numЬеrs of spесiеs to thе Сrеtaсеous dinosaurs, Ьut wеrе still small, nonе biggеr than thе sizе of a small dog. Although thе Сеnozoiс еra is сommоnly сallеd thе agе of mammals, it in fасt rеprеsеnts only a third of mammalian еvolutiоnary history, whеn mammals radiаtеd out into largеr Ьody sizеsto fill thе typеs of largе land vеrtеЬratеniсhеs prеviously hеld by thе dinosaurs.Thе еvolution of Сеnozoiс mammals is Ьеst undеrstood in thе сontехt of thе сhanging pattеrns of thе еarth's сontinеnts and thе subsеquеnt сhangеs in gloЬal сlimatе. Although the supеrсontinеnt Pangaеa startеd to Ьrеak up during thе Меsozoiс, thе southеrn сontinеnts Wеrе still unitеd in Gondwana at thе start of thе Cеnozoiс, and thе northеrn сontinеntal Ьloсks had not yеt rеaсhеd thеir final positions. Movеmеnt, fragmеntation'and сoalеsсеnсеof сontinеntal platеs сrеatеd сhangеs in oсеan сurrеnts and еpisodеs of mountain Ьuilding that rеsultеd in gloЬal сlimatiс сhangеs.To a first approximation thе world сhangеd during thе Сеnozoiс from initially gloЬally warm' tropiсal-likе сonditiсlns to a world that Ьесamе inсrеasingly сoldеr at thе higher latitudеs and inсrеasingly driеr throughout. Thеsе сhanging gloЬаl сlimatiс сonditions сonsеquеntly influеnсеd thе typеs of mаmmals that еvolvеd. For ехаmplе, thе есologiсal niсhеs now fillеd Ьy аnimals suсh as polar Ьеars and сamеls wеrе not in ехistеnсе until around 5 million yеars ago' with thе dеvеlopmеnt of an Arсtiс iсе сap and thе dеsеrtifiсationof tropiсal rеgions. AdditionalIy' thе isolation of diffеrеnt sееd groups of mammals on diffеrеnt сontinеntal bloсks (аlthough this mainly
707

Маmmаls pull down Ьranсhеs. Мammals likе this еvolvеd among thе hсlrsе-rеlatеd сhaliсothеrеs in thе Northегn Hеmisphеrе and Afriсa, among nativе ungu. latеs and giant ground sloths in South Amеriсa, аnd among womЬat-rеlatеd forms in Australia. A Ьriеf history of Сеnozoiс mаmmalian distriЬution is as follows. At thе start of thе Сеnozoiс, Afriсa was isolatеd from thе othеr сontinеnts and еvolvеd its own spесializеdfaunа (е.g.'еlеphаnts);primatеs wеrе also known еarly on in Afriсa, Ьut othеr northеrn immigrants (suсh as сarnivсrrеsand ungulatеs, or hoofеd mаmmals) did nоt rеaсh thеrе until thе еarly Мioсеnе, around 20 million yеars ago. Thе monotrеmеs Wеrе thе oгiginal Australian inhabitants; marsupials (immigrating from South Amеriсa via a thеn-iсе-frее Antaгсtiсa) Wеrе not known until thе еаrly Еoсеnе, around 55 million yеars ago. South Amеriсa was isolatеd until thе middlе Plioсеnе (2.5 million yеars аgo), whеn thе Isthmus of Рanama formеd. Its original fauna сonsistеd of еdеntatеs (sloths' armadillos, and antеatегs),marsupials (сlpossums аnd Ьorhyaеnids, now-еxtinсt prеdatory forms), and nativе ungulatеs (now all ехtinсt). Around 40 million yеars ago it gainеd its stoсks of primatеs and сaviomorph (rеlаtеdto guinеа pigs) rodеnts' most likеly from аnimals rafting ovеr from Afriсa. AЬсlut 2.5 million yеars ago many fоrms migratеd from North Amеriсa, аnd now ovеr half thе South Amеriсan fauna is of rесеnt northеrn origin (е.g.,сats, foxеs' tаpirs, dееr, and mousеlikе rodеnts).North Amеriсa and Еurasia havе long had fairly Ьroad faunal сonnесtions,Ьut today their mammal faunas arе morе similar than in many Past timеs. For ехamplе, North Amеriсan dееr and Ьison arе reсent (Within thе pаst 3 million yеars) Еurаsian immigrants. During thе еarly Сеnozoiс (thе Pаlеoсеnе and еarly Еoсеnе еpoсhs, from 65 to 50 million yеars ago) thе world was in gеnеral warm and еquaЬlе and' with thе Ьrowsing pгеssurе of thе hеrЬivorous dinosaurs геmovеd, was largеly сovеrеd in forеsts;tгopiсаl-likе forеsts ехtеndеd еvеn within thе соnfinеs of thе Arсtiс Сirсlе. Thе typеs of mammals Prеsеntwеrе largеly аrЬorеal insесt and fruit еatеrs'with a fеw tеrrеstriаlomnivorеs аnd hеrЬivorеs.Small prеdators inсludеd еаrly mеmЬеrs of thе modеrn ordеr Сarnivora, Ьut largеr prеdators wеrе not divеrsе and bеlongеd to groups now ехtinсt. Most of thеsе mammals havе Ьееn tеrmеd аrсhаiс typеs, mеaning that thеy Ьеlongеd to linеagеs that did not pеrsist until thе prеsеnt day (indееd,most Wеnt еxtinсt Ьеforе thе еnd of thе Palеoсеnе).Thе start of thе Еoсеnе saw thе first appеaranсеof primatе and modеrn ordеrs of ungulatеs(with thе first rodеnts appеaring in thе latеst Еoсеnе) and also thе highly spесializеd Ьats аnd whalеs. Thе first known fossil Ьats arе alrеady сlеarly spесializеdfliеrs, and wе havе littlе information on thеir anсеstry. Howеvеr, in thе past dесadе a spесtaсularsеriеs of еarly fossil whalеs hаs Ьееn сollесtеd that сlеarly shоws thе transition from a land animаl to a sессrndаrilyaquatiс оnе. Around 50 million yеars аgO tеmpеraturеs in thе highеr latitudеs startеd to fall, rеsulting in inсrеasеd sеasonality zrnd wintеr frosts. By thе start of thе oligoсеnе (33 million yеаrs ago) thе tropiсal forеsts wеrе сonfinеd to the еquаtorial rеgion, and dесiduouswoodland sprеad aсross muсh of thе North.

еrn Hеmisphеrе. Thе l сonfinеd to thе trtlpiсs сats) madе an appеarа hеrЬivorеs)Wеrесomг rathеr than fruit еatеrs took ovеr somе of tht еаrly Мioсеnе, around and drying during thе J thе sprеаd of savann Long-1еggеdungulatе in North Amеriсa (hor tivе forms). Howеvеr, 1 Wеrе not in еvidеrrсеu ing in thе latе Сеnozt transformation of thеs lеss prairiе' with thе lс million yеars ago) сoo Northеrn Hеmisphеrе dееr todау and woоlly nеw high-latitudе haЬ and drying rеsultеd in iсal Afriсa and Asia, rv that was formеrly сom

в|BLloGRAPHY

Agusti,J., аrrdM. Ant6n Ycаrs сf Маmmаliаt Prеss. Bеnton,М. J.2004, Vеr МA: BlасkwеllPuЬ Сifеlli, R. I-.2001.Еаrly 12\4-1226. J a п i s ,С . М . 2 0 0 1 .V i с t o еd.,Thе Book оf Li Kеrnp,Т. S. 2005.Т/:e( UnivеrsityPrеss. Z., Kiеlan-Jаwсlrowskа, сlf Diпosаurs:Оrigi UnivеrsityPrеss. Pсlugh,F. Ll., с. М. Jаn SaddlеRivеr'NJ: Bt Thеwissеn,J. G' М., аnс Bir maсroеvolution. Turnеr,A', and М. Antt Еuolutioп of thе Аf UnivеrsityPrеss. Vаughan,T. A.' J' A. Rv P h i l а d е l р h i аS :a u n

Маmmаls lvеd among thе horsе-rеlatеd d Afriсa, among nativе ungua, аnd among womЬat-rеlatеd triЬution is аs follows. At thе .om thе othеr сontinеnts and rts);primatеswеrе also known nts (suсhas саrnivсrresand un:hеrеuntil thе еarly Mioсеnе, |sWеrеthе original Australian rth Amеriсa viа a thеn-iсе-frее 'сеnе'around 55 million yеars dlе Рlioсеnе(2.5 million yеars [ts original fauna сonsistеd of ), marsupials (opossums and rnd nativе ungulatеs (now all rеd its stoсks of primatеs and rostlikеly from аnimals rafting lo mаny forms migratеd from r Amеriсаn fauna is of rесеnt and mousеlikеrodеnts).North l faunalсonnесtions'but today many pаst timеs. For ехamplе, .ithin thе past 3 million yеars) Lndеarly Еoссnе еpoсhs' from ;еnеralwarm and еquаЬlе and, dinosaursгеmovеd,was largеly еd еvеn within thе сonfinеs of ]ntwеrе largеly arЬorеal insесt геsand hеrЬivorеs.Small prеdn ordеr Сarnivora, Ьut lаrgеr groups now еxtinсt. N4ost of эs,mеaningthat thеy Ьеlongеd lnt day (indееd,шlost wеnt еxart of thе Еoсеnе saw thе first rngulatеs(with thе first rodеnts Lе highly spесializеd Ьats and y сlеarly spесializеdfliеrs, and Howеvеr, in thе past dесadе a :еnсollесtеdthat сlеarly shows rrily aquatiс onе. n thе highеr latitudеs startеd to ntеr frosts. By thе start of thе Ll forеsts wеrе сonfinеd to thе rеаd aсross muсh of thе North-

еrn Hеmisphеrе. Thе arсhaiс manrmаls Wеrе now all ехtinсt, primatеs wеrе сonfinеdto thе tropiсs, and morе modеrn typеs of largе prеdators (dogs and сats)madе an appеaranсе'Rodеnts and raЬЬits (or еquivalеnt typеs of small hеrЬivorеs)Wеrе сomпlon, and thе ungulatеsWеrе largеr and mostly lеaf еatеrs rаthеr than fruit еatеrs.In South Amеriсa largе rсldеnts (likе ttlday's сapyЬara) took ovеr somе of thе small ungulatе niсhеs. A warming trеnd during thе еarly Mioсеnе, around 20 million yеars ago' followеd Ьy suЬsеquеntсooling and drying duгing thе lаtег Мioсеnе (12_.5million yеars ago), Ьrought with it thе sprеad of savannа-typе haЬitats (trееd grasslands) at highеr lаtitudеs. Long-lеggеdungulatеs'with tееthmodifiеd for еating grass,Ьесamеprеvalеnt in North Amеriсa (horsеs),Еurasia (antеlopе),and South Amеriсa (ехtinсtna. tivе forms). Howеvеr, thе еquivalеnt typеs of marsupiаl, thе largеr kangaroсls, Wеrе not in еvidеnсе until thе Plioсеnе in Australia. Furthеr сooling and drying in thе latе Сеnozoiс (from around 8 million yеars аgсl) rеsultеd in thе transforrтationof thеsеpгoduсtivе savanna haЬitats into lеss produсtrvеtrееlеssprairiе' with thе loss of largе mammal divеrsity. Plio.Plеistoсеnе(from 5 million yеars ago) сooling rеsultеdin thе iсе agеs (largеlyехpеriеnсеdЬy thе Northеrn Hеmisphеrе),and spесializеdmammals (suсh as musk oх and rеindееr today and woolly rhino аnd mammoths in thе rесеntpast) inhaЬitеd thе nеw high-latitudе haЬitats suсh as tundra. Howеvеr, iсе-agе gloЬаl сoolirrg and drying rеsultеdin thе dеvеlopmеntof еxtеnsivеsavanna haЬitats in trоpiсal Afriсa and Asia, whiсh todаy prеsеrvеthе typе of largе.mammal divеrsity that was formеrly сommon worldwidе. BIBLIOGRAPHY Agusti,J'' and M. Ant6r-r.2002' Маmmаls,Sа|lеrtooths, апd Hоmiпids:65 Мillioп Yeаrs of МаmrпаliапЕuоlиtiсlпin Еuropе. Nеrv York: СоlurnЬiaUnil'еrsitу Prеss. Bеnton,М. J.2004. Vеrtеbrаtс Pаlаеoпtologу. Зrd сd. Сhaps.5 аnd 10' Маldеn, MA: BlaсkwеllPuЬlishing. Сifеlli,R. L. 2001. Еarly mаmmalianradiаtion s..|oиrпаlof Pаlесlпtologу 75: 1214-12.26. suссеssiсln. ln S..|.Gould' Janis,С. М' 2001.ViсtсlrsЬy dеfault:Thе mап"rn-ralian еd.,Thе Book of Lifе' 2nd сd., 166_217.Nеw York: W. W. Norton аr-rd Сo. Kеmp' T. S. 200.5.Thе origiп апd Еuolutioп of Маmmаls.()хfоrd: Oхford UnivеrsitуРrеss. Kiеlan.Jaworowska, Z.' R. I-.Сifеlli,andZ.-X. l-uo.2004.Маmmаlsfrom thе Аgе of Diпrlsаurs:Оrigiпs, Еuoltttiсlп,апd Struсturе.Nеw York: СсllumЬia UnivеrsityPrеss. Pough,F. H., с. М. Janis,andJ. 13.Неisеr.2008. Vеrtеbrаtе l'ifе,8th еd.Uppеr SaddlеRivеr,NJ: BеnjaminСumrnings. T h е w i s s е n , . ] . G . Мa. 'n d S . B a j p а i . 2 0 0 1\.W h а l еass а p o s t е сr h i l df o r maсroеvolutiоп. BioSсiепсе5 |: 10З7_1О49. Turnег,A., and M. Ant6n. 2004' ЕuoluiпgЕdеп:Ап ]llltstrаtеd Guidе tсlthе Еurllцtioпсlf thе Аfriсап l,аrgе-МаmmаlFаuпа.Nеw York: СolumЬia UrrivеrsityPrеss. Vaughаn,T. A., J. A. Ryen,аnd N. Сzаplеwski.)000. Маmmаlоgу.4tЬ'еd. -С.J . Philadеlрhiа: PuЬlishing. Sar-rndеrs

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710

Man,s Plaсе in Naturе

NIаn,s Plасe in Nаture (Thomas Hеnry Huхlеy) Thomas Hеnry Huxlеy's Мап's Plасе iпNаture (1863) (thе full titlе is Еuldепcе аs to Маn's Plасе iп Nаture, but it is alwаys known Ьy thе shortеr titlе, whiсh appеarеd on thе spinе) was thе first Еnglish book aftеr Darwin's oz thе Оrigiп of Spесiеs to rеlаtе humans аnd apеs anatomiсally and in еvolu. tionary tеrms (thе Оrigin had avoidеd thе suЬjесt).And it did so in punсhy prosе for gеnеral сonsumption. Its inсеption lay in Нuxlеy's disputе with thе antitransmutationist Riсhard Owеn. Owеn, an ехpеrt on apеs (inсluding thе gorillа' disсovеrеdin thе 1840s), plaсеd mankind in a nеw suЬсlass, Arсhеnсеphala (ruling Ьrain), in 1858. Hе insistеd that humаns possеss uniquе сеrеЬral hеmisphеrеs,whiсh dividе into a ..hippoсampus minor.'' third loЬе, whosе latеral vеntriсlе сontains a protruding Huхlеy, a Ьiologist аt London's Sсhool of Мinеs, hatеd owеn's hautеur ..thеrеis and providеntialism and rеspondеd in 1858 by stating that vеry littlе grеatеr intеrval аs апimаls Ьеtwееn tЬe Gorillа k the Маn than ехists bеtwееn thе Gorillа & the [ЬaЬoon|'' (lесturе 10, Marсh 16, 1858, Royal Institution Sеriеs,Prinсiplеs of Biology, January 19_Marсh 23, 1858' Нuxlеy Papеrs,Impеrial Сollеgе, l,ondon, З6.100). This sеntimеntstands at thе hеart ..Thеology Parsondom'' in his talks of Мап's Plасе iп Nаturе. Сritiсizing & to artisans in 1859, Huхlеy addеd that humans and animals .,must havе proсееdеd from onе anothеr in thе way of progrеssivе modifiсation'' (Huxlеy 1859). It was, hе told a friеnd, ..as rеspесtaЬlеto Ье modifiеd mоnkеy as modifiеd dirt'' (lеttеrto Frеdеriсk Dystеr' January З0, 1859, Huxlеy Papеrs, Impеrial Сollеgе, London, 15.106). Bеforе tЬe Оrigiп appеarеd,Huxlеy had polarizеd thе issuе сlf human еvolution vеrsus сrеation. owеn rеassеrtеdhis сlaim at thе mееting оf Oxfoгd's British Assoсiation for thе Advаnсеmеnt сrf Sсiеnсе in 1860. From thе floor сamе Нuхlеy's pointеd ..on thе Zoologiсal Rесontradiсtion, and from his pеn a suЬstantiatingеssay lations of Mаn with thе Lowеr Animals'' (1861),whiсh showed that apе Ьrains possеssеvеry ..uniquе'' human fеaturе.Thе disputе,whiсh еxplodеd publiсly in tЬ'eАtbепаецm tn 1861, alеrtеd rеspесtaЬlеsoсiеty to human еvolution. Thе paupеr prеssеshаd long rеlishеd an aristoсraсy-humЬlingЬеstial origin, and Hr'rxlеywas tapping this groundswеll for support. Не portrayеd еvolution as sеlf-Ьеttегmеnt:it grаntеd dignity to humЬlе origins. Huхlеy's artisan tаlks' running through 1862, foгmеd thе sесond сhaptеr of Мап's Plасе in |хIаture(thеrе wеrе only thrее сhaptеrs).Sеrеndipity providеd thе third. Sir Сharlеs Lyеll, who was writing hts Апtiquitу сlf Мап, askеd Нuхlеy's viеws on Nеandеrthal lv[an (found in 1856). Huхlеy's еnsuing Royal Institutionlес..On Fossil Rеmains turе of Man'' (Huхlеy 1858-1862) would frnisЬ,Мап's Plаce iп Nаturе' and hе garnеrеd aссounts of living apеs for an opеning сhaptеr. |f Маn's Plасе iп Nаturе was lеss assеrtivеon еvolution than his lесturеs, it would still priсk Viсtorian vanitiеs, not lеast Ьy suggеstingthat humans might go baсk far into gеologiсаl timе. A n i n i t i a l p r i n t i n g o f ] , 0 0 0 с o p i е s h i t t h е Ь o o k s t a l l si n F е Ь r u a r y 1 8 6 3 . Darwin had nеvеr ..rеad anything grandеr'' than thе сlosing of thе middlе

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it сamе to еvoluti from Сharlеs l)arwin. Т or paradigm; thе fоrmеr wondеr that Huхlеy at с rеtiсеnt' namеly human dеsignеd to show Ьеyon grеat apеs. Мost pеoplе thаt оur souls arе insеrt

сhaptеr (lеttеr to Hux t h е r е l i g i о u s p r е s sW a tion of mind and spее rеprint. Thе only bar shillings, ехpеnsivе fol Mivart was griеvеd to ,, сlb s cепitiеs,,, showing ropе (unpuЬlishеd lеtt Darwin Сollесtion, Un original). I-yеll's Antiqиitу of 1 turе. TЬe first madе m; sсooping thе modеrn v sand apеs for his anсеs

BIBLIOGRAPHY

Anonymous.1863,Еuid FеЬruary28'287_2 Darwin, С. 1999.Тhе Сс CambridgеUnivеrs

Маn's Plaсе in Naturе

.ry Huхlеy) rе (186З) (thе full titlе is Еzi.aysknown Ьy thе shortеr titlе, rglish Ьook aftеr Dагwin,s on lеs anatomiсally and in еvoluljесt).And it did so in punсhy tе antitransmutationist Riсhard ;orillа,disсovеrеdin thе 1840s), rala (rulingЬrain), in 1858. Не эmisphеrеs'whiсh dividе into a ..hippoсampus minor.'' ltruding Мinеs, hatеd owеn's hautеur ..thеrе is vеry lit_ y stating that rillа k the Мап than еxists Ье: 10, Мarсh 16' 1858, Royal : y 1 9 _ М a r с h2 3 , 1 8 5 8 , H u х l е y rissеntimеntstands at thе hеart rgy & Parsondom" in his talks ,,must havе prors and animalrs ;rеssivеmodifiсation'' (Huхlеy Ьlе to Ье modifiеd monkеy as uary 30, 1859, Нuxlеy Papеrs, э origin appеarеd,Huхlеy had сrеatlon. oхford's British Assoсiation for lе floor сamе Huхlеy's pointеd ..on thе Zoologiсal RеLgеssay ), whiсh showеd that apе brains isputе,whiсh еxplodеd puЬliсly s o с i е t yr o h u m a n е v o l u г i o n . .istoсraсy-humЬlingЬеstial orifor support. Hе portrayеd еvorumЬlе origins. Huхlеy's artisan lond сhaptеr of Маn's Plасe iп эndipityprovidеd thе third. Sir , of Мап, askеd Huxlеy's viеws .'s еnsuing Royal Institution lес858-1862) would frnish Мап's o f l i v r n ga p е s f o r a n o p е n i n g еrtivеon еvolution than his lес_ not lеast Ьy suggеsting that huэ Ь o o k s t a l l si n F е Ь r u a r y 1 8 6 3 . than thе сlosing of thе middlе

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Whеn it саmе to еvolution'Thomas Hеnry Huхlеy hаd vеry diffеrеntmotivеs from Сharlеs l)arwin. Тhе lattеrwаntеdto providеan ovеrall sсiеntifiсthеory or paradigm;thе fоrmеr wаntеd mаtеrialtо fight thе Сhristians.Thеrе is littlе wondеrthat Нuхlеy at onсе piсkеd up on that aЬout whiсh Darwin Wаs so rеtiсеnt'namely human еvolution.This frontispiесесlf Маn's Plасе in Nаture is dеsignedto sЬow ЬеyonddouЬt that wе humans arе from thе samе stoсk as thе grеatapеs.Мost pеоplеаgrееd,althoughto this day Сhristiansusually arguе thаt our souls arе insеrtеdmiraсulously.

с h a p t е r ( l е t t е rt o H u х l е y , F е Ь r u a r y 2 6 , 1 8 6 З , D a r w i n 1 ' 9 9 9 ,| 1 : 1 8 0 ) . B u t thе rеligious prеss Was stunnеd, and many notеd thе lасk of any rесognition of mind and spеесh. Brisk salеs nесеssitatеdan immеdiatе 1,000-сopy rеprint. Thе only Ьar to its falling into gruЬЬiеr hands was thе priсе: six shillings, ехpеnsivе for a 159-pagе tomе. Еvеn so, thе Сatholiс St Gеorgе Мivart was griеvеd to sее translations at Itаlian railway stations alongsidе ,,obsсeпities,', showing that thе strееt-lеvеlfasсination strеtсhеd aсross Еuropе (unpuЬlishеd lеttеr from Мivart to Сhаrlеs Dаrwin, April 25' 1870' Darwin Сo1lесtionU , n i v е r s i t y L i Ь r a r y , С a m Ь r i d g е ,F o l d е r 1 7 1 ; е m p h a s i si n original). Lуe||'sAпtiquitу of Мап was puЬlishеd within days of Мап,s Plасe in Nа..a ture.TЬe first madе man hundrеd thousand yеars', old' said onе rеviеwеr' sсooping thе modеrn worldviеw, and thе sесond gavе him ..a hundrеd thou. s a n d a p е s f o r h i s a n с е s t o r s ' (' A n o n y m o u s 1 8 6 з ) . BIBLIOGRAPHY Anсlnymous. 186З.Еuidепсе{1sto Ма||'sPlаcсiп Nаturc [rеviеw]. Atbепаеum, FеЬruary28,287-288, Dаrwin, С. 1999, Тhе Сorrеs1loпdепсе of СhаrlеsDапuill' Vol. 11. СamЬridgе: СamЬridgеUnivеrsityPrеss.

711

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Маrgulis Dеsmond, ^. 1997, Huхlеу: From Dеui!'s Disсiplе tсl Еuolutioп's High Priеst. Rеading, МA: Addisсln-'Wеslеy. Gross, С. G.1993. Hippoсаmpus mirror and man's plaсе ill naturе:A сasе stlrdy in thе soсial сonstruсtion of nеuroаnatomу. Нippr',саm|>пs 3: 40З_415. Нuхlеy, T. Н. 1858_1862. on fossil rеmаir-rs of mаn. Prtlсеatliпgsrlf tbе RolаI I nstitut i сlп сlf С r еаt B ritа i tl: 1Ii,420-422. -Гhе 1859. Sсiеnсеаnd rеligiorr. Buildеr,Januarv 1.5. 1861. on thе zoologiсаl rеlirtionsof man with thе lowеr аnimals. ТЙс Nаturаl Historу Rеuiеlu: 67_84' 1863. Еuidenсе аs to Мап's Plасе iп Nаture. Lсlndtln: \й/illiаms аnd Norgаtе. L,vеll,С. 786З. Thе Апtiquitу rlf Мап. Lопс.lоn:Jоhn Мuгrа,v. Lyons' S. L. |997. Сoпvinсing mеn thеy аге monkеvs. Irr A. P. Baгr, еd., Thсlmаs Hепrу Нltхlеу's Plасе iп Sсiеttсеапd Lеttеrs: Сеlttеttаrу Еssays, 95-l l8. Athеns: Univеrsity of Gеorgia Pгеss. Owеn, R. 1858. on thе сharaсtеrs,prinсiplеs сlf divisiоn, and primаry groups of thе сlass mammalian. Jourпаl of tbc Proсееdiпgs tlf thе I-iппаеап Soсiеtу (Zotllogу) 'l'_З7. 2: .W.ilson, L. G. 1996. Thе gorilla and thе quеstion of humагl oгigins:Thе Ьrlin сontrovеrsy. Jсlurпаl tlf tllе Нis|orу ll|-Мadiсinc апd Аllicс! ,\сiспсеs 57: -А.D. 184-2()7.

to work as a unifiеd v winiаn strugglе than matеriаl fгom оnе or1 tеria. Тhis viец. has work on thе human р fеrrеd sidеways in thi howеvеr сlЬtainеd, it as a сomplеmеnt to D In rесеnt yеars' ais( N4argulis (togеthеrw Sagan) lras Ьееn a st еarth as i1norganismi so signifiсаntly that it ехpесtеdly hеapеd сr gists еquatе thе Gaiz еqually еxpесtеdly st vinсеd of thе гightnе

Мargulis, Lynn (ь. 1'9З9)

l\4argulis, L. |970. Оrtg for а,Гhесlrуtf thе oп tbе Prесаmbriа 200Q.Sуmbiot Маrgrrlis,L., аnd D' Sa Еuсllцtiоп.Nеw Yo

l,ynn Mаrgulis, a longtimе profеssorof gеosсiеnсеsilt thе Univеrsity of Mаssaсhusеtts'Amhегst, is propеrlv сеlеЬratеdfoг hеr stГongildvoсaсy of thе oгi. gin of еukurryotесеlls (сеlls witlr a nuсleus) frotn trtorеprimitivе prokary
вlвLIoGRAPl])

lvlarsh,othniеl (

othniеl Сharlеs Мal ninеtееrrtlr_сепtury An PеaЬody, and his сon riсh fossil Ьеds of thе \ usеd many of his fossi Мarsh was Ьorn in Shеffiеld Sсiеntifiс Sсh Еtrropе rеturnеd to b unсlе finаnсеd thе Pеа ехpеditiсlns that Мars hе was politiсаlly astu еmy of Sсiеnсеs(hе sе ogist of thе U.S. Gес сonnесtioll to Lrоosth fiеrсе fеud with Еdwa thе narrringand dеsсri in this volr.rmе). Hе dit Marsh's tеams disсс

Маrsb ,сlF,uriutiсlп'sНigh Priest. plaсеin nаturе:A сasе sttrdy in ()саmpL|s 3: 40З-415. n. Proсecсliпgsrl|.thе Rowl п u a r уl 5 ' ''ith thе lorr,еranir-rrаls.T/.,c з. l-rlnсlоn:\Хlilliamsand n Murray. уs. In A. P. Bаrr, еd.,Thomаs (пtё1аr\'Еssаv-s,95_l l 8. visiоn,аnd primаry grorrps of thе 'f thе I'itlпаеап Sсlсiеtу (Zoologу) I humаrrсlrigiIts:Тhе Ьrain е апd Аlliеd Sсiепсеs 51:

-А.D,

to work as a unifiеd wholе. Shе sееsеvolution lеss in tеrms of a ruthlеss Darwinian strugglе than аs a proсеss Ьasеd on tЬе sidеways transfеr of gеnеtiс matеrial from onе organism to anothеr, сarriеd via miсroorganisms likе Ьaсtеria' This viеw has Ьееlr rесеivеd with somе skеptiсism, although rесеnt work сln thе hurrrirngеnomе strongly suggеststhat gеnеtiс matеrial is transfеrrеd sidеways in this fashion. Sinсе Dаrwinism works on gеnеtiс variation, howеvегoЬtаinеd, it is pгobaЬly Ьеrtеrto tlrink of this sort of phеnonrеnon as a сomplemеnt to Darwinian еvolution than аs an opposing viеw. In rесеnt yеаrs, :.rlsoguidеd Ьу hеr philоsophy of haгmony and mutualism, Margulis (togеthеr with Dorior-r Sagan, hеr son from hеr mаrriagе to Сarl Sagaп) has Ьееn a Strong аdvoсatе of thе Gaia hypothеsis, whiсh sееs thе еaгthas an organism and as sеlf-rеgulating'at lеast Llntil hLlmansdisruptеd it so signifiсantlythat it сould no longеr funсtion propеrly. .I.hisadvoсaсy has ехpесtеdly hеapеd сritiсism on Мargtrlis's hеad-пrany сonvеntionаl Ьiologists еquatе thе Gaia hypothеsis with prе-Сhristian naturе woгship-and еqually ехpесtеdly shе is morе tilan prеparеd to wеаthеr thе stoГm' сonvinсеd of tlrе rightnеssof hеr сausе. в|вLIoGRAPнY

]nсеsat thе Univеrsity of N4аsshеr strong adv
Margrrlis,L. 1970. Origiп of Еuhаrуotiс Сalls:Еuidепсеапd Rеsеаrсh]mDliсаtitlпs for а T|tеоrуоf the Оrigiп апt! Еuo|utiсlпof Мiсro|liаl,PIапt,апd Апimаl Сеlls oп thе PrесаmbriапЕаrth. Nеw Hаvеn, СT: Yаlе UnivеrsityPrеss. 2ОО0'SуmbiotiсPlапеt:А NеtuLсlok аt Еt,olutillп,Nеw York: Bаsiс Books. М a r g u l i sI, . . , а n d D . S a g a r -1r9. 9 7 . S l а п t е d T r u t h s : Е s s а у s с l п G а i а , S у m b i o s i s а п d Еuolutit.lп.Nеrд.York: Сopеrniсus Books.

-М.R.

Мarsh,othniеlСharlеs(1s31-1s99) othrriеl СЬaгlеs Маrsh was tЬе most influеntial palеontologist in latеninеtееnth-сеntuгyAmеriса. Hе еxploitеd tlrе wеalсh of his unсlе, Gеorgе PеаЬody, and his сonnесtions with thе U.S. Gеologiсal Survеy to ехplorе thе riсh fossil Ьеds of thе Wеst. Hе Wаs an еnthusi:lstiсsupportеr of Darwinisnr and usеd many of his fоssil disсovеriеsto prоvidе еvidеnсе in support of еvolution. Мarsh was Ьоrn in Loсkport, Nеw York, irr 1831' Не wаs гrаinеd at thе Shеffiеld Sсiеntifiс Sсhool of Yalе Univеrsity аnd aftеr thrее yеars of study in Еuropе rеturnеd to Ьесonrерrofеssor of pаlеontology at Yаlе in 1866. His unсlе finanсеd thе PеаЬody Мusеum at Yalе and providеd funds for thе п-rany еxpеditions that Маrsh sеnt to tЬе !Иеst' Although Маrsh Was a rеsеrvеdmirn, hе was politiсally аstutе and Ьесаmе a powеrful figr.rrеin thе Nаtional Aсаdеmy of Sсiепсеs(hе sеrvеdas prеsidеntfгom 188З to 1895). Hе was palеontologist of thе U.S. Gеolоgiсal Sr-rrvеyfrom 1882 тo |892 and еxploitеd this сonnесtion to Ьoost his оwn privatеly finanсеd ехpеditions. Hе еngagеd in a fiеrсе fеud with Еdward Drinkеr Сopе ovеr aссеss to W,еstеrnfossils and ovеr thе rraming and dеsсriptitln of spесiеs (sееalsсrthе аlphaЬеtiсal еntry on Сopе i n t h i s v o l u m е ) .H е d i е d i n 1 8 9 9 . Marsh's tеаms disсovеrеd mar-rynеw spесiеs of fossil maпrmals and rеptilеs.

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On a lесturе tour t() thе Unitеd Stаtеs'Тhomas Неnry Lluхlеy was Ьowlеd ovеr Ьy othniel Marsh,s сollесtion of horsе fossils.To makе thе сasе for еvolution in а puЬliс leсtuге,hе used this reсonstruсtionof hoгsееvolution(somеthlngwе now know to Ье muсh morе Ьranсh-likе),prеdiсtingthаt soon a fivе-tоеd anсеstor would Ье disсovеrеd.Tо his dеlight' soon thеrеаftеra spесimеnwith rudimеntaryfifth toеs was disсovегеd.(Мarsh сal[еdit Еohippиs,..dаwnhorsе.'' It was thеn disсоvеrеdthаt spесimеnshad Ьееnfound еarliеr,althoughnot idеntifiеdаs horsеs.Thе еaгliеrname, Н1,rасotbеrium' takеs prесеdеnсе, althoughoЬviouslyМarsh's namе has stuсk.)

H i s с t l l l е с t i o no f h o r s е tinuous sеquеnсеof еvо modеrn horsе, a sеquе е v i d е n с ео f е v r l l r t t i l l n t r с n d o f i n с г е а s е ds p е с although thе truе storv М а r s h а l s

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anсеstoг. Likе Huхlеy, muсh fr.rгthег llirсk ill gс N4arsh was аn еnthl с o n с е r n l r i m s е I fr r i r h r l natural sеlесtion woulс саrrsеintеlligеnсеWаs а The lпtroduсtit.lп апd t h а t p a | е o n t o l o g vp r o v ing Ьrain sizе in thе сou iсаl produсtof ninеtее

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Маss Ехtiпсtioпs His сollесtion of horsе fсlssils(sееfigurе)gеnеratеdWhat appеarеdto Ье а сontinuous sеqLiеnсеof еvolutiоn frtlm tlrе snrаll fotrг-toеdЕсrсеrrеЕohippus to tЬe пrodеrn horsе, :l sеquеnсе that Tlrсlmаs Hеnry Нtlxlеy сallеd ..dеmonstгativе еvidеnсеof еvolution'' (Нuхlеy 1888,90). Thе fossils sееmеd to irrdiсatеa trеnd of inсrеasеd spесialization Ьy adaptation to running on thе оpеn plains, although thе truе stoгy of thе horsе fаmily turnеd out to Ье far morе сomplех. M;rrsh аrlsodisсovеrеd toothеd Ьirds from thе Сrеtaсеtlr.rs,whiсh hе dеsсriЬеd in a monograp6, ()dсlпtсlrпitbеs\1880). Likе thе Ьеttеr_knownАrсlltlеoptеrух from Gеrmany' thеsе wеrе hailеd zrsimportant сonfirmation of thе viеw that Ьirds had еvolvеd from rеptilеs. Thе hеad of оnе of Мarsh's Ьirds, Iсhthуornis, was suЬsеquеntlyfound to Ьеlong to а marinе rеptilе. Мarsh disсovеrеdand naпlеd a largе numЬег of dinсlsaursаnd also studiеd thе еvolution of а group of giаnt еaгly mamtnаls hе сallеd Dinoсеrаtа. In his n-rorrogгaph on this group (l886) hе traсеd tlrе origin of tlrе Ungulata Ьaсk to:r hypothеtiсalСrеtасеous anсеstor.Likе Нuxlеy, hе Ьеliеvеd that thе origin of ordеrs and сlassеslay muсh furthеr baсk in gеologiсal timе than thе еarliеst known fossils. ]VIarshwas an еnthusiastiсsuppoГtеr of Darwinism, although hе did not с()nсегnhimsеlf with thе dеtails of how еvolution rvсlrkеd.Hе Ьеliеvеd that natuгal sеlесtiorrwould gradLrirllvfavоr thе irrсrеasingsizе of thе Ьrаin Ьесausе intеlligеnсеwas an importirnt adaptivе advаntagе.In his 1877 аddrеss T'hе lпtroduсtir>п аnd Suссessioп of Vertеbrаtе Lifе iп Аmеricа hе arguеd thаt palеontologу providеd сiеar pгoof of this adaptivе trеnd toward inсrеasing Ьrain sizе in thе сOllrsеof еvсllution.Maгsh's law of Ьrain growth is a typ. iсal produсt of rrinеtееr-rth-сеntllry progrеssionisr еvolutiorrism. B|вLloGRAPнY Huхlеy,T. H. l888. AmеriсапAddrеssеs, tuithа Lесturеoп tЬеStudуof Biohgу' Nеw York: Applеtоn. Nlаrsh,o. С. 1877. llttroduсtiсlпаnt!Sttссеssitlп сlf Vеrtсbr,ttеLifе iп Аmеriса:Ап Аddrеss Dеliuеrеd bеfсcrсttct: А МoпogrLlр|) of tlп Ехtiltсt Оrdсr tlf Gigа|ltiс h7Ll77I|пLlls, Washingtсlrr,L)С: Mсlnоgrарrhsоf thе U.S' Gеolrlgiсll Survсу, vol. t0.

Hеnry Huхlеy was Ьowlеd ovеr o m а k еr h ес а s еf o r е v o | u t i o ni n orsеevolution(somеthingwе ring tЬat soon a fivе-toеd on thеIеаftеra spесirrlеnwith allеdit Еobippиs,..dawnhorsе.'' foundеarliеr'althoughnot еri um, takesprесеdеnсе,

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Мass еxtinсtions Мass ехtinсtions arе gloЬal саlаrniсiеsсlf Ьriеf сlurirtionin whiсlr largе numЬеrs of spесiеs from divеrsе haЬitаts arе destroyеd.Thеy arе thr:s distinсt from morе rеgional еxtinсtion еVеntsthat oftеn oссur Ьесausеof normal gеologiсal proсеssеs.For еxапrplе, spесiеs that arе rеstriсtеd to a maгinе еmЬа,vn-rеnt or а lakе nlаy go ехtinсt if thеir hаbitat is gradually infillес]with s е d i m е n г .I t t с t r t t t r а ь tг,h е g l . l l l a l I l J t u г е t l I n l . t s sс х t i l 1 с t i ( ) l lrsе q i t i г е ss t r r l l e

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Маss Ехtiпсtioпs gloЬal-sсalесatastrophе' oftеn involving thе nеar shutdown of all photosynthеtiс aсtivity. Suсh disasгеrsrеquirе mаjor сhangеsof thе еarth'sсlimatе and oсеan сirсulation systеm. Thе most famous of thеsе g1oЬаl disastеrs is thе giant mеtеoritе impaсt that is thought to havе tеrminatеd thе rеign of thе dinosaurs 65 million yеars ago. This is known as thе K-T еvеnt Ьесausеit marks thе Ьoundary Ьеtwееn thе Сrеtaсеous pегiod' whiсh is spеllеd with a K in Gеrmаn, and thе fоllowing Tеrtiary. Howеvеr, this is not thе only mass ехtinсtion of thе fossil rесord. Plots of ехtinсtion ratеs through timе (sее figurе) rеvеаl grеat vаriability, with fivе major pеaks сlеarly sееn and pеrhaps twiсе this numЬеr of smaliеr еxtinсtion еvеnts.Thе major pеaks arе known аs thе Ьig 5 mass ехtinсtions' with thе K-T еvеnt bеing thе most rесеnt. How. еvеr' Ьy fаr thе Ьiggеst mass ехtinсtion of all timе was аround 250 million yеars at thе boundary Ьеtwееn thе Pеrmian and Triassiс pеriods. This P.Tr or еnd-Pеrmian еvеnt saw thе loss of morе tЬan 90oЬ of all spесiеs.This сatastrophе was as dеvastаting on land as it was in thе sеas and oсеans and, uniquеly, was also a sеvеrе сrisis for tеrrеstrial plants. In othеr еxtinсtion еvеnts plants gеnеrally farеd muсh Ьettеrthan animals.

с A U s E so F M A s s Е x т | N с т | o N s Thе idеa that mass ехtinсtions havе punсtuatеd thе history of lifе has Ьееn around fсlr a long timе. Thе rеason that most mass-ехtinсtionеvеntsoссur at mаjor Ьoundariеs of gеologiсal timе, suсh as Ьetwееn thе Сrеtaсеous and Tеrtiary' is that thеy mark major disсontinuitiеsin thе history of lifе and thus arе usеful markеrs for thе suЬdivision of gеologiсal timе. Thеsе timеs wеге oЬvious еvеn whеn suсh intеrvаls wеrе Ьеing dеfinеd in thе еarly ninеtееnth сеntury. Howеvеr' thе intеnsivе study of thе сausеs of mass ехtinсtions is a muсh morе rесеnt sсiеnсеthаt сan Ье datеd to thе puЬliсation of a study Ьy .Waltеr, Luis Alvarеz, his son and two сollеaguеs in 1980 (Alvaгеz еt al. group 1980). This mеasurеd thе сonсеntrationsof thе еxсееdinglyrarе traсе mеtal iridium in sеdimеntsthat straddlеd thе Сrеtaсеous-Tеrtiarytransition. For thе most part this mеtal oссurs in tiny amounts in thе еarth's сrust, Ьut thе Alvarеzеs аnd сollеаguеs found a dramatiс еnriсhmеnt prесisеly at thе lеvеl of thе mass ехtinсtion. Thеy suggеstеdthаt this iridium сamе from a сhondritiс nrеtеoritе(onе of thе most сommon typеs of n-rеtеoritе) and got into thе sеdimеnt from fallout in thе aftеrmath of a giant impaсt. Thе iridium anomaly has now Ьееn dеtесtеdin dozеns of loсations аround thе world, and this, togеthеr with thе disсovеry of thе impaсt сratеr in thе Yuсаt5n Pеninsula of Мехiсo, has еnsurеd that thеir hypothеsis is now widеly aссеptеd. Thе сratеr is loсatеd nеar thе villagе of СhiсхuluЬ and is Ьuriеd Ьеnеath youngеr sеdimеnts.It may Ье as muсh as 180km in diamеtеr, making it onе of thе largеst irnpaсt сratеrs known on еarth. In thе original 1980 artiсlе thе link Ьеtwееn thе impaсt and thе rеsultant mass ехtinсtion was thought to havе сomе aЬout from thе gloЬal darknеss that would follow suсh a largе impaсt. Thе еnеrgy of suсh an еvеnt would pulvеrizе Ьoth thе mеtеoritе and targеt гoсks into dust and finе droplеts of

Сomparisсln of ехtinс largе mеtеoritе сrаtеrl rесognizеd еxtinсtion еruption of largе volс сoinсidеs with а mass

liquid and Ьlast thег thеy would stay susр pеrhaps еvеn yеarsal dеvastating for thе p most есosystеms.Tl thгough thе food сhа whiсh would diе of s sшnlight. It appеars l еnd. This original ki addition of various < sitе is vеry unusuai iл This would havе bее сеntratеd typе of aсid this сornеr of Mехiс to hit. T h е 1 9 8 0 sa n d 1 9 impaсt with eхtinсti< pliсаЬlе to all ехtinс tinсtions in whiсh tl spaсеd еvеry 26 milli nation that is unlikс

Маss Ехtiпсtioпs aг shutdown of irll photosynrgеsof thе еarth's сlimzrtе and : thеsеgloЬal disastеrs is thе r tеrminаtеdthе геign of thе l а s t h е K . T е v с n t Ь е с а u s еi t егiod,whiсh is spеllеd with a еvеr'this is not thе only mass Jtion rаtеs through timе (sее lеаksсlеагlysееn аnd pеrhaps . Thе mаior pеaks arе knоwn rt Ьеing thе most rесеnt. FIowtimе Wxs around 250 million l Triassiсpеriods.This P-Tr or )0"Ь of аIl spесiеs'This сatas_ in thе sеas and oсеans and, i а l p I a n t s .I n o t h е r е x t i n с г i o n animаls.

еd thе history of lifе has Ьееn nаss-ехtinсtionеvеntsoссur at ; Ьеtwееnthе Сrеtaсеous and зs in thе history of lifе and thus logiсal timе. Tlrеsе timеs wеrе dеfinеdin thе еаrly ninеtееnth : сausеs
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Маss Ехtiпсtioпs various astronomiсal sсеnarios Wеrе proposеd whеrеЬy thе еarth was suЬjесtеd to dеvastating mеtеoritе and/or сomеt showеrs evеrу 26 million yеаrs. Нowеvеr, suЬsеquеntstudy of thе fossil rесord and improvеd agе dating of thе roсks has shown that sеvеral of thе 26-million-yеar ехtinсtion еvеntsdo not еxist (for ехamplе, thеrе was no ехtinсtion eуent 26 million yеars aftеr thе dеath of thе dinosaurs).Nonе of thе ехtinсtion еvеnts that rеmain show a rеgular spaсing. For ехаmplе, thегеWas a mass еxtinсtion 200 million yеars ago, known as thе еnd-Triassiс еvеnt, followеd Ьy а smallеr-magnitudеехtinсtion еvеnt 20 million yеars latеr in thе еarly Jurassiс.Thе nехt еxtinсtion еvеnts did not oссur until thе Crеtaсеous' ovеr 80 million yеars latеr, and thеsе wеrе all vеry minor affairs сomparеd with thе K-T еvеnt. Attеmpts to link othеr еxtinсtion еvеntswith mеtеoritеimpасts havе so far provеd rathеr unсonvinсing, mainly Ьесausеof a laсk of еvidеnсе.For ехamplе, thе Maniсougan Сratеr of northеrn Ontario, Сanada' is roughly 70% thе sizе of thе СhiсxuluЬ сratеr. It is onе of thе largеst сratеrs known Ьut sееms to havе had littlе or no еffесt on ехtinсtion ratеs. Thе сratеr was formеd 220 million yеars ago at a timе markеd Ьy vеry low eхtinсtion ratеs. Нowеvеr, it is worth noting that a giant impaсt сratег datеd to thе Ьoundary of thе Pеrmian and thе Triassiс has rесеntly Ьееn rеportеd from thе northwеst Australian сontinеntal shеlf, thus linking in timе a Ьig сratеr with thе Ьiggеst mass еxtinсtion. Howеver, thе сlaims for this сratеr hаvе Ьееn trеatеd with skеptiсism Ьy thе gеnеral sсiеntifiс сommunity, whiсh rеgards thе struсturе as morе likеly to Ье of volсaniс origin, and it rеmains to Ье sееn whеthеr thеsесlaims gain ассеptanсе. If thе link Ьеtwееn impaсts and еxtinсtions is gеnеrally wеak' thе samе сannot Ье said for giant volсaniс provinсеs. Thе surfaсе of thе еaгth is markеd by sеvеral suсh provinсеs that arе сomposеd of layеr upon layеr of Ьasalt lava flows that typiсally ехсееd 1 million сuЬiс kilomеtеrs in volumе. Thesе еruptеd from long fissurеs or сraсks, and individual flows oftеn ехсееdеd 1,000 сuЬiс kilomеtеrs in volumе' a figurе that is two or thrее ordеrs of mag.Within nitudе largеr than thosе sееn during eruptions in historiсal timеs. thе past 10 yеars improvеd agе dating of thеsе volсаniс provinсеs has rеvеalеd two rеmarkaЬlе faсts. First, most of thе provinсеs appеar to havе еruptеd in lеss than 1 million yеars; a gеologiсal Ьlink of an еyе. Тhus thе еnvironmеntal сonsеquеnсеs of suсh еruptions would havе Ьееn сonсеntratеd into a short intеrval. Sесond, many of thе volсaniс provinсеs hаvе Ьееn found to prесisеly сoinсidе with ехtinсtion еvеnts. Indееd, it now appеars that еvеry еxtinсtion еvеnt in thе past З00 million yеars, inсluding thе mass ехtinсtions, сoinсidеs with thе еruption of a giant volсaniс provinсе. This inсludеs thе K-T еvеnt, whеn thе Dессan Trap provinсе of India was formеd. Howеvеr, not еvеry giant volсaniс provinсе сoinсidеs with an ехtinсtion еvеnt.In othеr words, therе arе morе volсaniс provinсеs than thеrе arе ехtinсtions. oЬviously, it would Ье niсе and nеat if еvеry provinсе сoinсidеd with a mаss ехtinсtion, Ьut thе history of thе еarth is dеfinitеlynot nеat. How сan volсanism сausе ехtinсtion? Мuсh rеsеarсh has foсusеd on thе сlimatiс еffесtsof thе two major volсaniс gasеsassoсiatеdwith thе еruption

of Ьasalt lavas: сarb dioxidе is a grееnh mosphеrе will сausе1 (Ьy rеaсtion with w. thе most notiсеablее tion of Mount St. H matе. Howеvеr, suс arе rainеd out of tht that thе еruption of gloЬal warming' sug morе importаnt сliш gloЬal tеmpеraturеl all lifе on еaгth. Thr tion of flood Ьasalt that lеads to a runa!

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If thе сausе of mass mass еxtinсtions arе portant turning poir еvеnts is that groups nanсе in thе aftеrnra mammаls in thе аftе Ьеforе this mass ехt iсally living in thе s nosauгs Wеrе mamп fornrs wе sее todаy nosaurs may also ow pеarеd in thе Triassi yеаrs of thеir histor} tеrrеstrial land aniп groЦps. Only aftеr tJ dinosaurs quiсkly ris In еffесt mass ехt into thе vaсatеd niс of this еvolutionary way from сommuni еnсе in thе ratеs of; oсеans сomparеd и highly suссеssfulgr shеlls. Thеy suffеrе idly within a millior wipеd thеm out). Iп of millions of yеars tinсtion еvеnt also

Моss Ехtinсtioпs l whегеЬythе еarth wаs suЬlowеrsеvеry 26 million yеars. c and improvеd agе dating of lion-1.еaг ехrinсtion еvеnts do n еvеnt26 nrillion yеагs aftеr .tiOn еvеntsthat rеmain show ss еХtinсtion200 million yеars ехd Ьy a smallеr-magr-ritudе T h е е х t i n с t ion n е х t у Jtrrassiс. l a t е r , a nd еr 80 million уеars h thе K-T еvеnt. t mеtеoritеimpaсts havе so far Г a lасk of еvidеnсе.For еxamlrio, Саnadа, is roughly 707" thе largеst сratеrs known but )n ratеs.Thе сratеr was formеd :rу low ехtinсtion ratеs. F{ow'atеrdаtеd t
of Ьasalt lаvas:саrbon dioxidе and srrlfuгdioxidе. As is wеll known' саrЬсln dioxidе is a grееrrhousеgas' and thе injесtion of largе volumеs into thе atmosphегеwill сausе gloЬal warming. In сontrast, sulfur dioxidе forms aеrosols (Ьy rеaсtion with wаtеr vapor) that Ьloсk sunlight аnd сausе сooling. Thus thе most notiсеaЬlе еffесt of mоdеrn lаrgе volсаniс еruptions, suсh as thе еruption of Mount St. Hеlеns in Washington Statе in 1980, is сooling of thе сlimatе. Hоwеvеr, suсh еffесtsarе ехсееdinglyshoгt livеd Ьесausеthе аеrosols arе rairrеdout of thе atmosphеrеin а yеar or so. Gеologiсal еvidеnсе shows that thе еruption of giant volсаniс provinсеs is nеаrly always assoсiatеdwith global wаrming, suggеstingtlrat thе егuption of сarЬon dioхidе may Ье thе morе inrportаnt сlimatiс еffесt of volсаnism. Нowеvеr, it is onе thing to raisе gloЬal tеmpеraturе Ьy a fеw dеgrееs and еntirеly аnothеr to wipе out nеarly аll lifе on еarth. Tlrеrеforе,many сurrеnt еxtillсtion sсеnarios sее thе eruption of floоd Ьasаlt prоvinсеs аs just а triggеr in a сomplех сhirin of еvеnts that lеads to a runaway grееnhousеsсеnario. сoNsЕoUENсEs oF MAss ExтINстloNs If thе сausе of mass ехtinсtions is still aсtivеly dеЬatеd, thе сonsеquеnсеs of mass еxtinсtiorrs аrе aЬurrdantly сlеar. Тhеy lravе long Ьееn rесognizеd as important turning points in tlrе еvolutiorr of lifе. An intriguing aspесt of thеsе еvеnts is that groups that wеrе insignifiсant Ьеforе thе ехtinсtion risе to dominanсе in tlrе aftеrnrаtlr.Thе quintеssеntialехaпrplе of this is thе suссеss of thе mammals in thе aftеrmath of thе K-T ехtinсtiorr. Мamnrals had a long history Ьеforе tlris mаss ехtinсtion' Ьut thеy spеnt this timе litеrally and mеtaphoгiсаlly living in thе shаdсlw of thе dinosaurs. only with thе dеmisе of thе di. nosaurs Wеrе mаmmals ablе to еvolvе into tlrе largеr sizеs and divеrsе Ьody forms wе sее today. Somеwhat pаradoхiсally, thе initial suссеss of thе dinosaursmay also OWеsomеthiпgto а nlass-еxtinсtionеvеnt.Dinosaurs first appеarеd in thе Triаssiс аround 230 million yеars ago' Ьut tor thе first 30 million yеars of thеiг history thеy wеrе gеnеrally only a rеlativеly small сomponеnt of tеrrеstrialland animal сomnrunitiеs,whiсh inсludеd m:rny othеr геptilе-likе groups. only aftеr thе еnd-Triassiс mаss ехtillсtion 200 million vеагs ago did dinosaurs quiсkly risе to total dominanсе of tеrrеstrialсommunitiеs. In еffесtmass ехtinсtions providе сlpportunitiеsfor the survivors to rаdiatе into thе vасаtеd niсhеs lеft Ьеhind Ьy thе еxtirrсtspесiеs.Нowеvеr, thе paсе of this еvolutionаry radiatiсlnis highly inсonstant and vаriеs in an intеrеsгing way fron-rсommulrity to сommunity' For ехamplе, thеrе is a distinсt diffеrеnсе itr thе ratеs сlf rесor,еryof сrеarurеsthzrtlivе in thе wаtеr сolumn of thе oсеans соmparеd with thosе that livе on thе sеafloor. Ammonoids wеrе a highly suссеssfulЕ.roup'distantly rеlatеd to squid, that had attraсtivе spiral shеlls. T.hеy sr.rffеrеd nulnеrous еxtinсtiolr еvеnts Ьut irlwаys rесovеrеd rap_ idly within a million yеаrs or so (еxсеptfor tlrе K-T ехtinсtion, whiсh finally wipеd thеm out). In сontrast, сlams that livе on thе sеaflоor oftеn took tеns of milli
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Маупаrd Smith plants and tеrrеstriаl vеrtеЬratеs. Plant сommunitiеs only Ьеgan to radiatе and rеturn to normal around 10 million yеars aftеr thе еxtinсtion еvеnt' whеrеas thе terrеstrial vеrtеЬratеs wеrе divеrsifying rapidly within 1 million yеars of thе ехtinсtion. In faсt' thе rесovеry intеrval aftеr thе еnd.Pеrmian еxtinсtion was ехсеptionally long. Prееxtinсtion divеrsity lеvеls wеrе not aсhiеvеd again until nеarly 100 million yеars aftеr thе mass еxtinсtion. In. dееd, for many sеafloor сommunitiеs thе rесovеry did not еvеn Ьеgin until 8 to 10 million yеars aftеr thе сrisis. Thе еxtгеme lеngth of timе it has takеn for еarth's есosystеms to rесovеr should sеrvе as a warning for thе сurrent man-madе mаss-ехtinсtion еvеnt. Gеologiсal history rеvеals that thе еarth's есosystеms arе aЬlе to rесovеr from еvеn thе most sеvеrе еnvironmеntal сatastrophеs, Ьut thе timеtaЬlе of гесovеry is sprеad ovеr millions of yеars, a timе span that is immеasuraЬly long from a human pеrspесtivе. If thе timе takеn for сommцnitiеs to rесovеr from modеrn dеgradation is of a similar duration, thеn it is сlеar thаt it is Ьеst to stop thе damagе from happеning in thе first plaсе. B|вLIoGRAPHY tlvarez. L. \и.. !(/.Alvarеz. F. Asaro. and H. V. }yliсhеl.1980. Еxtratеrrеstrialсausе for thе Сгеtaсеous-Tеrtiary еxtinсtion:Ехpеrimеntalrеsultsаnd thеorеtiсаl appliсation.Sciепсе208: 1095_1108. Bесkеr,L., R.J. Porеda'A. R. Basu,K. O. Popе'T. М. Harrison,С. Niсholson'and R. Iasky.2004. Bеdout:A possiЬlееnd-Pеrmiаnimpaсt сratеroffshorеof northwеstеrnAustralia.SсieпсеЗО4: 1469-\476. Bеnton,М. J. 2003. Whеп Lifе Neаrlу Diеd: Thе GrеаtеstМаss Ехtiпсtioп of All Time. Lond,on:Thamеs and Hudson. Сourtillot, У. \999. ЕuolutioпаrуСаtаstrсlphеs: Тhе Sсieпсeof МаssЕхtiпсtiсlп. Cambridgе:СamЬridgеUnivеrsityPrеss. Hallam, ^.20О4. Саtаstrophеsапd LesserСаlаmitiеs:Тbе Саusеsof Маss Ехtinсtioпs.oxford: Oхford UnivеrsityPrеss. Hallam' A., and P. B. Wignall. 1997. Маss Ехtiпсtioпsапd Thеir Аftermаtb. oxford: Oxford UnivеrsityPrеss. Looy, С. v.,.!и.A. Brugman,D. L. Dilсhеr,and H. Vissсhеr.1999.Тhе dеlayеd resurgеnсеof еquatorialforеstsa{tеrthе Pеrmian-Triassiсесologiссrisis. Proсееdiпgsof the Nаtioпаl Асаdеmу of SсiепсеsUSA 96: 1з857_\з862. Wignall, P. B. 1992,Тhе dаy thе world nеarlydiеd. Nеш Sсiепtist,jаnuary 2.5' 51-55. 2001. Largе ignеousprovinсеsand massехtinсtions.Еаrth-SсiепсеRеuiеt't,s

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Мaynaгd Smith, John (1920_2004) John N4aynard Smith Was thе leading British еvolutionary Ьiologist of thе sесond half of thе twеntiеth сеntury. Hе dеvеlopеd a kееn intеrеst in natural history as a сhild, largely without any hеlp from adults. As a sсhoolЬoy at Еton Сollеgе hе Ьесamе aсquaintеd with thе writings of J. B. S. Нaldanе, largеly bесausе Haldаnе's outspokеn Marхism wаs anаthеma to his tеaсhеrs' whosе job was to train thе nеxt gеnеration of thе British ruling сlass. Aftеr studying еnginееring at СamЬridgе Univеrsity and doing war work in airсraft

faсtoriеs, hе studiеd Haldanе was thе !7еl studеnt of Haldanе's i at UсL without takin of thе Sсhool of Biolo rеmаinеd for thе rеst part of this timе. As sсhool with сonsidеrс сhology, nеuroЬiologу at Sussех was a mесса world. Haldanе ехеrtеd a rеnownеd for thе сlar of thеir knowlеdgе an munist for many yеar 1956 whilе rеmainin Ьoth aсtivе аnd suссе N4aynard Smith's сasi danе was irasсiЬlе an his сollеaguеs.Не wat tionally good at intе niority. Hе was rеma prеtеntiousnеss. Hе startеd his Ьiolо Drosophilа subobsсu еvolutionary studiеs. madе two notaЬlе сor thе еffесts of inЬrееdi D. sиbobsсurа, whiсh lесtion Ьy fеmalе сhoi< twеntiеth-сеntury еvo пеtiсаl Thеorу сlf Nа goс rеntly fashi<-lnaЬlе Maynard Smith also r aging. Hе providеd a produсtion and oЬta aging' Drosophilа is n linеs of rеsеarсhwеrе muсh rесognition as t] dеvеlopmеntalgеnеti a prеpattеrn and Ala diffusion proсеssеs' Aftеr moving to Sr work, еspесially in еvс ЬесausеHaldanе, by v Ьесausеof thе Ьurdеn

Маупаrd Smith nitiеs only Ьеgan to radiatе ; aftеr thе еxtinсtion еvеnt' ring rapidly within 1 million r е r v a la f t е r t h е е n d - P е г m i а n ln divеrsity lеvеls wеrе not ftеr thе mass еxtinсtion. Inеry did not еvеn Ьеgin until ]arth's есosystеmSto rесovеr madе mass-еxtinсtionеvеnt. tеms arе ablе to rесovеr from s' Ьut thе timеtaЬlе of rесov. n that is immеasuraЬly long сommunitiеs to rесovеr from еn it is сlеar that it is Ьеst to

сausе nеl.1980.Ехtratеrrеstrial :ntalrеsultsand thеorеtiсal v4.Harrison,С. Niсholson,and impaсtсratеrоffshorеоf ). 'еаtеstМаssЕхtiпсtioп of Аll Sсiепcеrf Маss Ехtiпсtioп. s: Тhе Саиsеsof Маss 'пsапd Тhеir Aftеrmаth. y'issсhеr. |999.TЬе dеlayеd n-Triassiсесologiссrisis. : ' sU S А9 ь : l 3 8 5 7 -l 3 8 6 2 . Nеш Sсiеntist' January25' inсtions.Еаrth -Sсiепсс Rеuiеъus -P.BW.

еvolutionary Ьiologist of thе lpеd а kееn interеst in natural om adults. As a sсhoolЬoy at writings of J. B. S. Haldanе, was anathеmato his tеасhеrs, thе British ruling сlass. Aftеr Lnddоing war work in аirсraft

faсtoгiеs, hе studiеd zoology at Univеrsity Сollеgе London (UсL), whеrе .$Иеldon Нaldаnе was thе Profеssor of Biomеtry. Hе Ьесamе a postgraduatе studеnt of Haldane's and took up an appointmеnt in thе zoology dеpartmеnt at UсL without taking his PhD. Hе lеft UCL in 1965 to Ьесomе thе first dеan of thе Sсhool of Biologiсal Sсiеnсеs at thе nеw Univеrsity of Sussеx, whеrе hе rеmainеd for thе rеst of his lifе' although hе was dеan during only a small part оf this timе. As an administrator hе was suссеssful in dеvеloping a sсhool with сonsidеraЬlе rеsеarсh strеngths, еspесially in еxpеrimеntal psyсhology, nеuroЬiology, and population Ьiology. For many yеars his own group at sussех was a mессa for visitors and postdoсtoral sсholars from around thе world. Haldanе еxеrtеd a lifеlong influеnсе on Мaynard Smith. Thеy wеrе Ьoth rеnownеd for thе сlarity of thеir lесturеs and writings, as wеll аs thе Ьrеadth of thеir knowlеdgе and intеrеsts.Likе Нaldanе, Maynard Smith was a Сommunist for many yеars, Ьut hе lеft thе party aftеr thе Hungarian uprising of 1956 whilе rеmaining Ьroadly lеft-wing in his politiсal viеws. Thеy wеrе both aсtivе and suссеssful сommuniсators of sсiеnсе to thе gеnеral puЬliс, in Maynard Smith's сasе through tеlеvision as wеll as writing. Bцt whilе Haldanе was irasсiЬlе and violеnt, Maynard Smith was kindly and Ьеlovеd Ьy his сollеaguеs. Hе was a highly еntеrtaining сonvеrsationalist and rvas еxсеptionally good at intеraсting with fеllow sсiеntists, irrеspесtivе of thеir sеniority. Hе was rеmarkaЬly opеn mindеd Ьut nеvеr foolеd Ьy nonsеnsе or prеtеntrousnеss. Hе startеd his biоlogiсal сarееr in thе 1950s Ьy working on thе gеnеtiсsof Drosophilа subobsсurа, whiсh Haldanе's group had dеvеlopеd as a tool for еvolutionary studiеs. Apart from somе Ьasiс work on gеnеtiс mapping, hе madе two notaЬlе сontriЬutions through this ехpеrimеntal work. Hе studiеd thе еffесts of inЬrееding on malе mating Ьеhavior and rеproduсtivе suссеss in D' subobscurа' wЬl,cЬ,сausеd him to rесognizе thе signifiсanсе of sеxual sеlесtion Ьy fеmalе сhoiсе of matеs. This topiс was largеly ignorеd Ьy most еarly twеntiеth-сеntury еvolutionary biologists' apart from R.A. Fishеr in Thе Gепetiсаl Theorу of Nаtиrаl Seleсtioп (19З0). Hе еvеn antiсipatеd thе сur. rеntly fashionaЬlе good-gеnesthеory of thе еvolution of fеmalе matе сhoiсе. Maynard Smith also usеd D. subobsсurа as a modеl systеm for thе study of aging. Hе providеd an ingеnious dеmonstration of thе survival сost of rеproduсtion and oЬtainеd еvidеnсе against thе somatiс mutation thеory of agiog. Drosophilа ts now a major tool for thе Ьiology of aging. Both of thеsе linеs of rеsеarсhwеrе yеars ahеad of thеir timе and proЬably did not gain as muсh rесognition as thеy dеsеrvеd. Hе also did somе pionееring work on thе dеvеlopmеntal gеnеtiсs of Drosopbila, stimulatеd Ьy Curt Stеrn's сonсеpt of a prеpattеrn and Alan Turing's thеoriеs of pattеrn formation by rеaсtiondiffusion proсеssеs. After moving to Sussех, Maynard Smith dеvotеd his timе to thеorеtiсal wоrk, еspесially in еvolution, and gavе up doing еxpеrimеnts. This was partly ЬесausеHaldanе, Ьy whom he always fеlt ovеrshadowеd, had diеd and partly Ьесausеof thе Ьurdеn of Ьuilding up a nеW dеpartmеnt.His thеorеtiсalwork

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Мaупаrd Smith was сharaсtеrizеd Ьy thе usе of rathеr simplе mathеmatiсal mеthods that сonсеalеd a good dеal of ingеnuity in thinking up approaсhеs to Ьiologiсally signifiсant problеms. This soпrеtimеsmеt with disapproval from appliеd mаthеmatiсians' who oftеn prеfеr to usе сomplех mеthods to solvе insignifiсant proЬlеms. Maynard Smith сontributеd importantly to еarly work on molесular variation and еvolution, using thе thеn nеwly proposеd nеutrаl thеory as thе Ьasis for sеvеral important puЬliсations. Thе most influеntial of thеsе is with his SussехсollеаguеJohn Haigh on gеnеtiсhitсhhiking (Мaynard Smith and Нaigh 1'974).This showеd quantitativеly how thе spгеad of an advantagеous mutation rеduсеs variаtion at linkеd nеutrаl loсi' Ьy dragging a сhromosomal sеgmеnt alоng with it. This сonсеpt has Ьессlmе vеry important in rеlation to thе avalanсhеof data on nаtural variaЬility at thе lеvеl of DNA sеqrrеnсеs' sinсе a vallеy of rеduсеd variaЬility сan Ье intеrprеtеd as thе signal of a rесеnt fixation of an advantagеousmutation. Anothеr fiеld to whiсh hе mаdе important сontriЬutions was thе еvolution of sеx and gеnеtiс systеms' starting in thе latе 1960s. Нis work hеlpеd frее this fiеld from its domination Ьy thе rathеr woolly group-sеlесtionist idеas of Сyril Darlington and Gеorgе Lеdyard StеЬЬins, whiсh had had a sеvеrеly nеgativе еffесt on its dеvеlopmеnt. In partiсular hе еmphasizеd thе proЬlеm of thе сost of sеx, whеrеЬy an othеrwisе sеlесtivеlynеutral asеxual variant аrising in a sехual population еxpеriеnсеsa transmissionаdvantagеand rapidly sprеads to fiхation. Maynard Smith was thе first pеrson to apprесiаtе thе diffiсulty this posеs for ехplaining thе prеvalеnсе of sеxual rеproduсtion among еukaryotеs. Hе madе numеrous population-gеnеtiсmodеls of proсеssеsthat сould providе an advantagе to sеХ or inсrеasеd rесomЬination' and hе summеd up thе statе of thе fiеld in his 1978 Ьook Тhе Еuolutioп of Seх, whiсh is still thе Ьеst survеy of this suЬjесt as a wholе. Thе study of thе еvolution of sеx and Ьrееding Systеms is now a flourishing disсiplinе within еvolutionary Ьiology, in no small part Ьесausе of Мaynard Smith's own work and his еnсouragеmеntof othеrs. A4aynard Smith's most influеntial singlе сontribution waS thе dеvеlopmеnt of thе сonсеpt of thе euolutioпаrilу stаblе strсltеgу(ЕSS),initiаlly in сollaЬo. ration with thе lаte Gеorge Priсе. This flowеd out of his lоng-standing intеrеst in animal Ьеhavior and his dеsirе to undеrstand why animal сonfliсts usually do not еnd in sеrious fighting. lt usеs thе prinсiplе that, for a trait valuе to rеprеsеntan еquiliЬrium undеr natural sеlесtiоn,a nесеssaryсondition is that all possiblе dеviant trait valuеs arе sеlесtivеlydisadvantagеous whеn introduсеd аt a low frеquеnсy into a population whеrе most individuals havе thе spесifiеd trait valuе. Dеtеrmining an ЕSS providеs а powеrful mеans of prеdiсting thе outсomе of sеlесtion in сasеs whеrе frеquеnсydеpеndеntfitnеssеsarе gеnеratеdЬy thе Ьiologiсal сontехt, suсh as sех ratios or soсial Ьеhаvior. Although this аpproaсh had Ьееn usеd Ьеforе for dеaling with sеx ratios' notaЬly Ьy R. A. Fishеr and.s7.D. Hamilton, Мaynard Smith dеvеlopеd ЕSS thеory еxpliсitly and appliеd it to many prеviously intraсtaЬlе еvolutionary prоЬlеms. It is оnе of thе most sсiеntifiсally fruitful appliсations of gamеs thеory. A hugе thеorеtiсal and еmpiriсal litеrаturе has sinсе dеvеl-

opеd' whiсh appliе Thеsе mеthods arе : ioral есology. Мayn . Еuolutiсlп аnd thе luсid and informativ Aftеr formal rеtirе Brian Spratt'smiсroL on molесulaг variati work was еvidеnсеl Ьaсtеrial сеlls in natr ods for еxamining th mеmЬеrs of Ьaсtеria DNA-sеquеnсе lеvеl (

rеmarkaЬlе fеаt of Ь rеputation as an еldе N4aynard Smith al tionary quеstions' in tion (thе lattеr tеrm еquiliЬrium, and thе wrotе a sеriеs of ех< ogy, сulminating in l Е6rs Szathmiry dеv tions in еvolution, frr thе еvolution of lang fесts of mеsothеliom rеsеarсh until his dе сharaсtеristiсally sti 2003 mееting of thе

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F i s h е r ,R . A . l 9 3 0 . Т Й e UnivеrsityPrеss. N4aynаrdSmith,J. 195 longеvitуof Dros 1 9 5 8 b .S е х u a 2з0_244.l-ondon 1 9 7 8 . T h еЕ u о 1982.L|uсlltt UnivеrsityPrеss. 1989.Еuolиti N4аynardSmith,J.' Е.. еvolutionary dynа Маynard Srтith,.|.,zln GeпеtiсаlRеsеаr Mаynard Smith,J., an oхford: oхford U

Маупаrd Smith е mathеmatiсalmеrlrсlds that up approaсhеsto Ьiologiсally lisapprtlvalfrom appliеd mathmеthodsto solvе irrsignifiсant tntlyt
ontriЬutionsWas thе еvolution е l960s. His work hеlpеd frее 'olly group-sеlесtionistidеas of ins, whiсh had had a sеvеrеly lar hе еmphasizеdthе proЬlеm сtivеly nеutral asехuаl variant ansmissionadvantagеand rap, t h е f i r s rp е r s o n t o a p p r е с i a t е vаlеnсеof sеxual rеglroduсtion modеls of proшlation-gеnеtiс . х o г i n с r е a s е dr е с o m Ь i n а t i o n , s l978 boоk Т/:с Еuolиtioп o| сt as a wholе. Thе study of thе .a flourishingdisсiplinе within of MaynzrrdSmithЪ own work rtriЬutionWas thе dеvеlopmеnt z/egy(ЕSS),iпitially in сollаЬoI o u г o f h i s l с l n g - s t а n d i n ign t е г dеrstand why animal сonfliсts s t h е p r i n с i р I еt h a t . f o г а t г а i t :al sеlесtion,a nесеssaryсondiarе sеlесtivеlydisadvantagеous lpulаtion whеrе most iпdividurg an ЕSS providеs а powеrfшl ion in сasеs whеrе fтеquеnсy_ g i с а lс o n t е х t .s t r с ha s s е х r a г i o s ad bееnusеd bеforе foг dеaling /. D. Hamilton, Maynard Smith ; to tnanyprеviously intгaсtablе :iеntifiсallyfruitful аppliсations ,iriсallitеraпrrеhas sinсе dеvеl-

оpеd' whiсh аpрliеs ЕSS mегhods tO many diffеrеnt Ьiologiсаl proЬlеms. Thеsе ntеthods arе a mainstay of muсh of thе thеory that undеrliеs Ьеhavioral есology. Maynard Smith rеviеwеd his сontriЬutions in his 1982 Ьook Еuollltiсlп аnd thе Тhеorl' of GL1ftlеs'whiсh is сharaсtеristiсallу Ьriеf Ьut luсid arrd informiltivе. Aftеr tЪrmal rеtirеmеntin 1985, Мaynard Smith startеdto сollаЬoratеwith BгiarrSprаtt'srniсroЬial gеnеtiсsgroup' thеn at Sussех.on thе analysis of dаtа on molесular variation anс]еvolutiorr in Ьасtеria. An inrportant rеsult of this work was еvidеnсе for muсh morе ехсhangе сlf gеnеtiс information among Ьaсtеriаlсеlls in nаturе than prеvior-rsly Ьеliеvеd.It аlso gеnеratеdnеW mrthods for еxamining thе еffесts of infrеquеnt rесomЬinаti
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Nlayr, Еrnst Waltеr (7904_2005) Еrnst !Иaltеr N4ayr was a Gеrman-Ьorn Amеriсаn ornithologist who playеd a сеntral rolе in еvolutionary thеory and systеmatiсs during thе twеntiеth сеntury. Hе was a strong advoсatе of two idеas: thе thеory of spесiation Ьy gеographiс isolation and thе Biologiсal Spесiеs Сonсеpt. Мayr also madе important сontriЬutions to Ьiogеography, systеmatiсs,and thе study of wholе organisms during a period whеn biology as a profеssiоn Ьесamе rеduсtionist. N{ayr was born into a profеssional Gеrman family. His fathеr diеd in 7977, and thе family ехpеriеnсеd сonsidеraЬlе finanсial trouЬlе during thе 1920s. Mayr's intеrеst in natural history stаrtеd with his fathеr. Не Ьеgan univеrsity in 192З' studying mеdiсinе at thе Univеrsity сlf Grеifswald. Dеspitе high marks' N4ayr switсhеd to zool
tion. Hе also wаs а Ornithologists' Uni N4ayr's сontriЬut hе foсusеd on thе thеory. Sуstеmаtiсs tionally and Ьесam was part of a small I in population gеnе еvolutionary proсе сialty, working сlos In approасh Мaу Hе passionatеiyadl that a population Ь сould oссur. In this thе making. on t| сonсеpt. This plaсе spесiеs.Thе biologi nisms and Ьarriеrst mесhanisms ехistеd most important mе tioп (\96З) prеsеn еmpiriсal and intеll ing еvolutionary stu nizеd thе Soсiеtyfo Еuolutioп (\947).Е vеrsational spасеs l сommon purposе ar i\{ayr's impaсt or N4ayr promotеd еvo Arthur Сain' among nеar thе spесiеslеvе сiplе of this approa tionships and to us taхonomiс dесision dееmеd suffiсiеnt to thought to Ье adapt that madе a group mеriсai taхonomy a ProfеssionallyМа ology. On thе onе strugglеd to сonvinс datе in Ьiologiсal sr strugglеd to draw tl сluding еvolution. С Ьiology in thе latе bodiеs and othеr gr

Мауr

'iсаnornithologist who playеd itепratiсsduring thе twеntiеth d е а s :t h е t h е o r y o f s p е с i а t i o n S p е с i е sС o n с е p t . M a y r a l s o hy, systеmatiсs'ilnd thе study Lсlgvas a prоfеssiorrbесamе rеfаmily.Нis fathеr died iл \917, l с i a l t r o u Ь l еd u r i n g t h е 1 9 2 0 s . h h i s f а t h е r .H е Ь е g а n t l n i v е r zеrsity of Grеifswаld. Dеspitе 25. Hе alrеady had dеvеlopеd lе п1ost important wеrе with ll llistory at thе Univеrsity of J n d е гh i s g u i d a n с еМ a y r с o m ribution and Ьiogесlgraphy of rwагd Strеsеmannhirеd N4ayr uinеa and thе Solomon Islands, is rеturn Mayr sought a pеrmaoffегs irr Еuropе failеd to rтatессеptеdtеmporary work at thе .lH) in Nеw York. L{е Ьеgan in l h i s o r n i r h о l o g i с aсl о l l е с t i o nt o o t Ь е rt h i n g s .M a y r w a s g i v е n а Lls.This kеpt him in Nеw York. 'r in Gеrmany, Мa,vr сhosе not rе (Grеtеl)Simon (1912-1990)' 'n important rolе in Mayr's сal also lookеd aftеr studеnts and lizеd аs U.S. сitizеns. , whеn hе aссеptеdan Agassiz ,е Zoo|ogу (МСZ) at Harvard '. {rom 196I to 1970. For Mayr ngе in status.Hе wаs now a full mеritusprofеssorаt Harvard in with thе MСZ ils lris Ьаsе. Ьirds of thе southwеst Paсifiс, ; and sеvеrаlfiеld guidеs. From Soсiеty of Nеw York and сonrts' Hе also madе сonsidеraЬlе rcrs,s Сhесk-list of Birсls of the rvisеdthе Сbeсk-list,snеxt еdi-

tion' Hе also was i]сtivеin many profеssionalsoсiеtiеs,suсh аs thе Arrrегiсan oгnithologists' Union. Мayr's сontriЬutions to еvolutionary studiеs Ьеgan in thе latе 19З0s whеn hе foсusеd on thе proсеSs of spесiation and madе сontriЬutions to gеnеral thеory. Sуstеmаtiсsапd tbe Оrigiп of Speсiеs (t942) rесеivеd praisе intеrnationally and Ьесarlrеa сornеrstonеin thе Synthеtiсthеory of еvolution. Мayr Wаs pаrt of а small group of Ьiologistswho thor:ghtthat rесеnt dеvеltlpnrеnts in population gеl.lеtiсsand Ьiogеography madе pсlssiblеa rigorotrs study of еvolutionary proсеssеs.During thе 1940s hе сonсеntratеdon this аs his spесialty, working сlosеly with Thеodosius DoЬzhаnsky, among othеrs. In approaсh Mayr еmphasizеd gеographiс isolation and polytypiс spесiеs. Hе pаrssionatеlyadvoсatеdthе thеoгy of allopatriс spесii1tion,whiсh rеquirеd that а population Ье physiсally isolаtеd Ьеforе divеrgеnсеinto zrtrеw spесiеs сould oссur. In this sеnsеgеographiсallydistinсt populations wеrе spесiеsin thе making. On thе samе linеs Mayr сhampionеd thе Ьiologiсal spесiеs сonсеpt. This plaсеd a prеmium on intеrbrееdingand gеnе flow in dеfining spесiеs.Thе Ьiologiсal spесiеsсonсеPt foсusеd attеntion on isolаting mесhanisms аrrd Ьarriеrs to gеl1еflow. Altlrough Маyr thtluglrtthаr many isolаting mесhanisms еxistеd as spесial саsеs, hе ссlnsidеrеdgеographiс isolаtion thе most important lnесhanism in n:lturе. Нis Ьook Апimаl Spесies апd Еuolutioп (1963) prеsеntеdhis viеws at thеir most dеvеlopеd. In addition to his еr-npiriсaland intеllесtuаlсontriЬrrtions,Мayr playеd a сruсial rolе in shapiпg еvolutionary studiеs into a сonrmrrnity.Largеly on his own, Mavr organizеd thе Soсiеtv for thе Study of Еvolution (|946) and launсhеd thе jсlurnal Еuolцtioп (1947\. Еасh requirеd ir gгеat dеаl of еffort, Ьut thеy prсlvidеdсonvеrsational spaсеs for еvolutiсlnary studiеs and hеlpеd dеvеlop il sеnsе of с o m m o n p u г p o s сa n d е х p е с t a t i o n ' Мayr's impасt on systеmаtiсs irlvolvеd sеverаl lеvеls. As a thеtlrеtiсian Мayr prornotеd еvolutionаr}.svstеIтlаtiсs rogеthеrwitlr Gеoгgе Simpstln and Arthur Сain, arrrongothеrs.This hаd spесial rеlеvаnсеfor taxonomiс groups nеar thе spесiеslеvеl:suЬspесiеs,spесiеs,and spесiеsgroups. Thе Ьasiс prinсiplе of this approaсh was to usе сlassifiсationto еxprеss еvolutionary rеlationships and to usе an undеrsttrndingof еvolutionary proсеssеsto makе taхonomiс dесisions' For instanсе, tl.lеprеsеnсе of gеographiс Ьaгriеrs was dееmеd suffiсiеrrtto draw Ьotrrrdаriеsin сlassifiсzltions.Likеwisе' сhаraсtеrs thought to Ье аdaptations to loсаl с
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Мауr

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gavе сrеdit to thos prоmotеd thе wori thеm on еqual fоo iсinе and ехpеrimе As a philosophе Ьеtwееn proхimatl intеraсtion of stгu proximatе сausеs work?'' In сontras words, аnswеrs to tion Ьеtwееn proх 1 9 5 0 s a n d 1 9 6 0 sЬ

вlвLloGRAF

тl BЕт

Boсk, W. 1994.Еrns еvоlution.Biсl/с 2004.Еrnst] 12]l:6З7_65| Мayr, Е. 1942' Sуst UnivеrsityPrеss 1 9 5 З .М е t h o Hill. 1 9 6 З .А п i m а 1982.Thе G,

5 t r е s е m a n n 't ' ' 1 9 / 5 ' Hаrvard Univеrs

Inhts Sуstеtltiltiсs "tпd thtl Оrigiп of Spесiеs(1942I, Еrnst Mayr maсlеmuсh of suсh phеnomеnaas ..ringsof raсеs,''whеrе mеmЬеrsof touсhingsuЬspесiеsсan intегЬrееdЬut whеn thе еnd populatitlnsсirсlе Ьасk аtrdttluсlr,lhе.е is .ер.oduсtivеisolation.Hеrе wе sееspесiеsir-rthе mаkir.rg. If thе middlе populations (of thе warЬlеr PhуIklscopustroсhiloidеs)wеrе сIiminatеd,wе w.,ulj huu. two sеparatеspесiеs'Thе suЬspесiеsin thе ring'arе У = uiridапиs;I,=lиdlotui; T=troсhiloidеs;О:obsсиrаtus; andp:plиmbеitаrl,ls.Thе сrоss.hatсhеdаrеa' in thе distriсt Ьеtwееnthе wеstеrnS:ryanМоuntаins irnd tlrе YеnisеiRivеr, is where ui r i dапlzsanсl p luпЙ еitа r sus.,u..lop.

supportirrgthе fiеld. His vision for systеmatiсsis Ьеst prеsеntеdin Мethods апd Prinсiplеs of S1t57g7nаtiс Zorllсlg1,(195З), rvhiсlr Ьесalnе а standаrd train. ing manual. In thе sесotld hаlf of his Iifе, Мayr Wrotе ехtеnsivеIyon thе lristory arrd philosophy of Ьio|ogy, еspесially on thеmеs rеlatеd to natttral history and еvolutiorr. His Ьook Thе Groшth of Biсllogiс"ll Thсlиght (19s2I was a signifi. сant сontriЬution to this topiс. Dаrwir-r Ьесаmе l.]nlmportant sr.rЬjесtfoг Мayr' as did many othеr kеy еvolutionists of thе past 100 yеars (е.g.'Karl Jоrdan). Мaуr's сontriЬшtionsаs а histсlгialrсеntеrеdon two thеnrеs.First, hе

}yIеmе

Thе tеrm meme \^/ ish Gепе t
Меme gavе сrеdit to thosе who dеvеlopеd thе idеas hе himsеlf dеfеndеd. Sесond, hе promotеd thе work of naturalist traditions in thе history of Ьiology' plaсing thеm on еquаl footing with othеr traditions in thе lifе sсiеnсеs' suсh as mеdiсinе and ехpеrimеntal Ьiology. As a philоsophеr Mayr is сhiеfly rеsponsiЬlе for promoting thе distinсtion Ьеtwееn prоximatе and ultimatе сausеs. By invеstigating thе opеration and intеraсtion of struсtural еlеmеnts, hе said' еxpеrimеntal Ьiology foсusеd on ..how'' quеstions, suсh as ..How doеs this prоximatе сausеs. Thеy askеd work?'' In сontrast, еvolutionary Ьiology sought ultimatе сausеs' in othеr ..why'' quеstions. As did his historiсal writing, thе distinсwords, answеrs to tion Ьеtwееn proхimatе and ultimatе сausеs arosе during сonfliсts in thе 1950s and 1960s Ьеtwееnеvolutionary and molесular Ьiоlogists. BlвLloGRAPHY Boсk, W. 1994. Еrnst Мayr, naturalist:Нis сontributionstо systеmatiсsand еvolution.Biсllogуапd Philosopbу9: 267-327. 2004.ЕrnstMayr at 100:A lifе insidеand outsidеof ornithologу.Thе Аuh 121:637-651. Мayr, Е. 1942.Sуstеmаtiсsапd thе Оrigiп of Speсiеs.Nеw York: СolumЬia UnivеrsityPrеss. 1'95З.Меthodsапd Priпciplеsof SуstеmаtiсZoologу. Nеw York: MсGrawHill. 1963.Aпimаl Spесiesапd Еuolиtioп.СamЬridgе,MA: BеlknapPrеss. -Гhoиght. СamЬridgе'МA: Bеlknаp Prеss. 1982. Тhе Groшth of Biologiсаl Е. \97 5. Оrпithologу:From Aristotlе to thе Preseпt.СamЬridgе,MA: Strеsеmann, Harvard Univеrsity Prеss.

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Меmе 12),Еrnst Mayr madе muсh of l Ь е r s t l f t t l u с h i n gs, u Ь s p е с i е sс а n laсk аnd touсh' thеrе is rеprol i n g .l { t h еm i d d l еp o p u l а t i o n s еliminatеd, wе would havе are У = uiridапиs; L: lиdlotui; itаrus. TЬе сross.hatсhеd arеa, tаinsalrd гhе YеnisсiRivег, is

сs is Ьеst prеsеntеdtn Меthods whiсh Ьесamеa standard trainеxtеnsivеlyon thе history and rеlаtеdto natural history and tl Thought (1'952)was a signifi]amе an importаnt suЬjесt for lf thе past 100 yеаrs (е.g.' Karl :еntеrеdon two thеmеs. F.irst,hе

Thе tеrm mеmе was сoinеd Ьy Riсhard Dawkins in Ьis 1976 Ьook The Selfish Geпе to dеsсriЬе units of сultural еvolution (as opposеd to gеnes,whiсh arе units of Ьiologiсal еvolution)' In thе intеrvеning yеars thе tеrm has Ьееn popularizеd, as еvidеnсеd Ьy its inсlusi on iп Тhe oхford Епglish Diсtionаrу, thе spawning of a dеdiсatеd (and now-dеfunсt) journal, and sеvеral monographs. Mеmеs сan Ье suсh things as songs' tools' stylеs of drеss, rеligious Ьеliеfs, hairstylеs, aphorisms, and myths. Dawkins originally еmployеd ..Univеrsal Darwinism',-thе thought that mеmеs to sеrvе as an instanсе of any systеm with disсrеtе units that ехhiЬit diffеrеntial fitnеss valцеs (varl'ation)' sеlесtion,and rеpliсation (hеrеdity)will еvolvе Ьy Darwinian mеans. '!7е arе сontinuLikе organisms, idеas appеar to ехhibit thеsе сharaсtеristiсs. ally inundatеd with idеas. Thankfully, most of this information is disсardеd (othеrwisеwе would havе mеmory ovеrload). Thus idеas arе in сompеtition with еaсh othег for survival within our minds; thе fit onеs rеsidе in our minds and gеt rеpliсatеd, whilе thе unfit onеs gеt disсardеd. Rеpliсation oссurs through imitation' Ье it through thе writtеn word, dеmonstration' or disсussions at thе dinnеr taЬlе. It is important not to сonfЦsе mеmеs' whiсh arе idеas, with thе rеfеrеnts of thе idеas. For ехamplе, thе mеmе аrro|Uhеаdshаrpеniпg is the idеа of a mannеr

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Мепdеl of produсing an arrowhеad, not thе аrrowhеad irsеlf. Тhis distinсtion prеsеrvеs thе gеnotypе/phеnotypеdiсhotomy witЬiп Ьiology, or, in Dawkins's tеrminology, thе diffеrеnсе Ьеtwееn rеpliсators and vеhiсlеs.Rеpliсators arе thе еntitiеs that сopy thеmsеlvеs and сodе fоr struсturеs that intеraсt in thе world (somе thеorists prеfеr thе t,erm iпtеrасtor to uеhiсle). This г:lisеs sеvеral points that distinguish mеmеtiс еvolution from сompеting сonсеptions of сultural еvolution. Сultuгal еvolution is oftеn sееll аs simply improving thе fitnеss of thе gгoup or group tnеmЬегs.For еxаrтlplе,fishhooks aпd arrowhеads еvolvеd to сonvеy a fitnеss advantagе to thе groups and individuals who usеd suсh artifaсts. Меmеs, howеvеr, сan Ье quitе suссеssfulwithout сonvеying а fitnеss advantagе to thеir hosts, еven to thе point of bеirrg dеlеtеriolls to thеir vесtors. Dawkins famously сlаims tlrat rеligion is a perriсularly suссеssfulЬut toxiс mеmе. Mеmеs arе fit wlrеn thеy havе high fidеlity and high feсundity unto thеmsеlvеs.Aссording to proponents' пlеmеs hold impliсations for our сonсеption of сulturе and human minds. Thе srrссеssof thе mеme mеmе' howеvеr, Ьеliеs its suссеss as a tеrm of art in thе aсadеmy. Critiсs havе idеntifiеd sеvеral problеrrrswith mеmеs, nоt thе lеаst of whiсh is that it is simply гесаstitlgan old idеа il-lnеw pасkaging. PеrЬaps it is not thе mеmеs thеmsеlvеsthat arе еxplirnatory Ьut thе undеrlying psyсhologiсal mесhаnisms rеsporrsiЬlеfor thе sеlесtion and rеpliсation of сегtain mеmеs thаt arе usеful for еxplaining сulturаl еvoiution. Furthеrmorе, it is unсlеar ехасtly what a mеmе is. It is еasy to сolтlе up with еxanrplеsof mеmеs' Ьut a сlеar irnd aссеptеd dеfinition rеmains еlr"rsivе. For еxilrrrplе,is a mеmе a part of а Bееthovеn symphony or thе еrrtirеsynrphorry?Until an operational dеfinition is found, tl.lеfruitfulnеssof this сonсеpt rеtllаins quеstionaЬlе. Finally' somе havе arguеd that thе lасk of fidеlity of mеmеs, as wеll as thеir sееmingly nondigital natltrе' srrggеstsa Lirmarсkian rathrr than а Dаrwinian еvolutiorrаryproсеss. Thе truе impaсt
Меndеl, Grеgor (t822_Т884) ..thе priеst who hеld Grеgor Johann Меndеl hаs Ьееn саllеd thе kеy to еvolution'' (Еisеlеy \959'205), Ьut in lris own day fеw Ьiologistshad еvеr hеard of him, Сhаrlеs Dаrwin inсludеd. His faпrilу was poor' Ьut hе souglrt supPort in a monastегy whеrе fortunе shonе upon him Ьy giving him tlrе mеans to сarry out his rеmarkaЬlе and aпrЬitiousеxpеrinrсnts. lvIеndеl, thе firstЬorn of Anton Меndеl and Rosinе Меndеl (nёе Sсhwirtliсh), wаs гаisеd in Gеrmаn-spеaking Silеsizl in thе littlе vill:rgе o{ Неinzеndorf. At 11 lrе аttеndеd sсlroоls far from homе, and at 18 hе еrrtеrеd thе Philosophiсal Institutе in Olгniitz, сomplеtil-tgl]is сoursеs thеге in 1843.

Thе stгain of studv сausеd Ьouts of sеvс This ехpеriеnсеlay b of Saint Thomas in I .,from thе bittеr strr

1 9s 4 ) .

At thе monastеl. oftеn-sad tasks of ; for.rndhim work as z еvеr, rеquirеd an ех Ьoth timеs. Aftеr tlrс Viеnna to obtain аd thе praсtiсal dеn-ron lnost rесеnt wоrk in N4еndеl's tеaсlrеr Viеnnа from Сathol ing Меndеl's timе ir havе krrown of this tеrs aсquirеd Ьy plal ral loсalеs. Latеr М suрport for thе inhе l21ntransmutatlons. possibiiity mе11tiO ЬotanistsJosеph KoJ sееking to еstаЬlish hyЬridization. Having rеturnесif tеst variеtiеs of tlrе lryЬridizatitl11ехpеr u аim, hе ехplairrесl, hyЬгid progеny аpp tion with сеrtainty, dеrtakе this progrilп сhzrraсtеrdiffеrеnсе to асhiеvе stirtistiсa ..fаr.rеaсhing' was . portant qlrеstion: organiс forms'' (St thеу сould forпr thе ..rеvеrtеd turnеd or Еvidеntly this rva tеsting his rеsеarсh puЬlishеd. Not unti Оrigiп of Spесiеs. sаgеs prеsеntingаrr was attaсking a tar[

Мепdеl еad itsеlf.T.his distinсtion pгеithin Ьiology, or' in Dawkins's rrsand vеhiсlеs.Rеpliсators arе |r stгtlсturеstlrat intеraсt in thе . t o r t o u е h i с l e ;T. h i s г a i s е ss е v ,n from сompеting сonсеptions еn sееnas sirnply improving tlrе еxamplе,fishhooks and arrowl to thе groups and individuals :аn bе quitе suссеssfulwithout еvеn to thе pсlint of Ьеing dеlеl a i n l sr h а t r е l i g i o n i s а p а r t i с u fit whеn tlrеy havе high fidеlity ing to prоponеnts, Inеmеs hold d huп-ranminds. эеliеsits suссеssas a tеrm of art lproЬlеms with mеmеs' not thе old idеa in nеw paсkаging. PеrехplanatoryЬut thе undеrlying hе sеlесtion and rеpliсation of еvolution. Furthеrmorе, ;r.rltural iy to сomе up with ехamplеs of . е m a i n sе l u s i v е .F o r е х а m p l е , i s . rhе еntirе symphorry?Until an l s sr ' f t h i s с o n с е p tr е m a i n s q u е s Laсkof fidеlit1.of mеп.lеs,as wеll its a Lamarсkian rzrthеr thzrn a npaсt of mеmеs for undегstanddеd.

Prеss. эrk:oxiord Univеrsit,v 'fordUnivеrsityPrеss. -.J.Z. rdon:Pеnguin.

priеstwho hеld thе kеy to еvoay fеw biologistshad еvеr hеard y Was po()r' Ьut lrе sought sup_ on him Ьy giving him thе mеans хpеrlmеnts. dеl аnd Rosinе Меndеl (n6е rg Silеsiа in thе littlе villagе of roпr homе, aпd at 18 hе еntеrеd lеtinghis с()ursеsthеrе in 1843.

Thе strain of study plus tutoring to providе his own funds had rnеanwhilе сausеd Ьoшtsof sеvеrеdеpгеssionand ехtеndеd timе Ьасk honrе to rесovеr. This ехpеriеnсе iay Ьеhind his dесision to apply to thе Augustinian Monastеry of Saint Thomas in Brtinr-r.Hе knеrv, hе ехplainеd, that hе nееdеdto Ье frееd ..from thе Ьittеr strugglе for ехistеnсе'' that hаd bееn his lot hithеrto (lltis

t9 s4\.

At thе monastеry Меr-rdеlprt>vеdunaЬlе to сopе еmotionally with thе oftеn-sаd tasks of a priеst, Ьut his aЬЬot' thе undеrstаnding Сyril N"рP, found him work as a suЬstitutе tеaсhеr inZnaim. Tеaсhег сеrtifiсation' howеvеr' rеquirеd an еxamination. This lrе took twiсе but thгough stгеssfаilеd Ьoth timеs. Aftеr thе first attеmpt thе aЬЬot sеnt Mеndеl to thе Univегsity of Viеnna to oЬtairr adеquаtе foundations irr thе sсiеnсеs.Thеrе hе assistеdin thе prасtiсal dеmonstrаtionsfor thе ph,vsiсsсoursеs arrd was ехposеd to thе most rесеnt work in plarrt сytology. Меndеl's tеaсhеr. thе Ьotanist Franz Llngеr' Was a viсtim of attaсks in Viеnnа from Сathсlliс quartеrsfoг his advoсaсy of spесiеstransпllltationduri n g M е n d е l ' s t i m е i n V i е n n a ( 1 8 5 1 _ 1 8 5 3 )a n d s u Ь s е q u е n t l yМ . еndеl must hаvе known of tlris аnd of Ungeг's transplant еxpегimеntsin whiсh сhаrасtеrs aсquirеd Ьy plants in novеl lraЬitаtswеrе lost on rеturning to thеiг natural loсalеs. Latеr Меndеl rеpеatеd suсh ехpеrimеnts and found in thеm nо support fсlr ti-rеinhеritanсеof aсquirеd сhаraсtеrs,thus ruling out Lamarсkian transmutations.Spесiеsmultipliсation Ьy hyЬridization, howеvеr, was a pоssiЬility mеntionеd Ьy Ungеr, for hе knеw thе woгk of thе Gеrmаn ЬotanistsJosеph Kбlrеutеr and Саrl von Girtnеr' who had hyЬridizеd plants, sееking to еstaЬlishwhеthеr spесiеsrеmain сonstant or сan сhangе through hyЬridization. Having rеturnеd frorrrViеnna in 185З, Mеndеl Ьеgan thе following yеar to tеst variеtiеs of thе еdiЬlе pеa for сonstanсy of typе in prеparation for thе hyЬridization ехpеrimеnts that oссupiеd him Ьеtwееn 1856 and |862. Ifis aim, hе ехplainеd, was tO ,.dеtеrminеthе numЬеr of diffеrеntforrns in whiсh hyЬrid Progеny appеar' pеrmit сlassifiсation of tlrеsе forms in еaсh gеnеration rvith сеrtilinty, and asсеrtzrinthеir numеriсаl intеrrеlаtiсlnshi1rs.'' To r.rn_ program hе сhosе variеtal diffеrеnсеsadvеrtisеdЬy nonЬlеnding dеrtakе this сharaсtег diffеrеnсеsthirt сould l-lесlеаrly distinguishеd' Awarе of thе nееd to aсlriеvеstatistiсallysignifiсantrеsults,he grеw largе populations' Thе task ..far-rеaсhing,'' was Ьut hе warnеd thаt it was thе only way to solvе thе im..thе portant qllеstion: dеvеlopmеntаl history fЕпtшiсkluпgsgeschiсhte]of organiс forms' (Stеrn and Shеrwood 1966, 2). If somе hyЬrids Ьrеd truе, thеy сould form thе Ьasis for thе dеvеlopmеnt of nеw spесiеs'Ьut if thеy rеturnеd oг ..rеvеrtеd''to thе origirrаtingforпts, no rrоvеlгywould rеsult. Еvidеntly this was thе quеstion hе sеt out to solvе in 1854 whеn hе Ьеgan tеsting his rеsеarсh mаtеrial. СЬаrlеs Dаrwin's thеory Wаs at that timе rrnpuЬlislrеd.Not until |862 did N{еndеlrеаd thе Gегman tгanslationof Оп thе origin of Spесiеs. Меndеl's most frеquеnt marginaliа thеrеin геfеr to passagеsprеsеntingаnd opposing tlrе doсtriгlе of spесial сrеirtiоn.Hеге Dаrwin Was attaсking а targеt rhаt Mеndеl, it appеars,did not ассеpt еithеr.

729

7З0

Мепdеl Thе сontехt of Mеndеl's famous ехpеrimеnts Was thus not Darwin's thеory of еvolution. It was instеad thе dеЬatе among Gеrman-spеaking Ьiologists' sеvеral of whom, likе Ungеr, had еspousеdеlеmеntsоf thе spесulativеtеaсhing of Nаturphilosophiе, prinсipally thе notion сlf thе suссеssivеdеvеlopmеnt of highеr and highеr forms of lifе ovеr an ехtеndеd pеriod of timе. Onе of thе Augustinians in Briinn, Matouё Kl5сеl, also supportеd a dеvеlopmеntal viеw of spесiеsorigins' Ьut unlikе his friеnd Mеndеl, Kl:iсеl was a spесulativеphilosophеr who nеvеr сarriеd out a rigorous sеriеs of ехpеrimеnts. Mеndеl was drawn сhiеfly to thе еxpеrimеntal litеraturе of thе Gеrman hyЬridists. His сhiеf rеsourсе was Сarl von G;irtnеr, who, in his Ьook F,хperiments апd Оbseruаtioпs of Hуbridizаtioп iп thе Plапt Kiпgdom (Vеrsuсhе uпd Beсlbасbtuпgen йbеr diе Bаstаrdеrzеиguпg im Pflапzeпreich' |849), found that fеrtilе hyЬrids yiеldеd progеny that tеndеd soonеr or latеr to rеvеrt to onе or thе othеr of thе originating spесiеs. Gzirtnеr listеd oniy a fеw hyЬrids that appеarеd to rеmain сonstant in thеir offspring, аnd it is signifiсant that Меndеl rеproduсеd many of thеsе hyЬrids and found that thеy did rеvеrt. Меndеl wеnt on to сhoosе hawkwееds (Hiеrасiиm) Ьесausе of thе multitudе of forms found in thе wild. Although thе Ьotanist Сarl Nigеli еnсouragеd him in this dirесгion, it was not hе who pеrsuadеd Меndеl to сhoosе this diffiсult gеnus' as is oftеn assеrtеd. Mеndеl rеasonеdthat polymorphiс gеnеramight owе thеir multitudеs of spесiеs to hyЬridization' Ьut of a diffеrеnt kind from that hе had found in his сlassiс еxpеrimеnts with thе еdiЬlе pеa (Pisum). Меndеl ехplainеd thе rеsults of Ьis Pisuпl ехpеrimеnts Ьy suggеsting that thеrе must Ье a proсеss of sеgrеgation (sее figurе) of thе diffеring potеntials

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lfilliam Batеsonwаs Меndеl's mouthpiесеin Britain in thе еarly yеаrs of thе twеntiеthсеntury.Тhis diagram shows his rеPгеsеntаtion of Mеndе['sfirst law, -l thе law of sеgrеgation.(From Batеsсln 909.)

prеsеnt in thе hyЬ сеlls arе еithеr of с сomЬinations of p еny of thе two kinс tios that hе found еgg сеlls of thе sar thе old idеa of onс a nеw variant will was also wrong. N dirесtly rеlеvant t< Darwin had found rеgation is thus sе Also from sеgrе in аll sorts of сoг pеndеntly of оnе : tion with this proс сlaim that domеst сorrеsponding wil' lifе.'' Instеad, hе o; Thе aссеptanсе adhеrеnсе to nonb сrеativе rolе of nat Ьlеnding stеp' thеr fеrеnсеs littlе Ьy li gеnetiсsinto Darw

в|BLIoGRA

Batеson'!и' l 909. ,\ UnivеrsityPrеs Е i s е l е yL, . 1 9 5 9 ,D а London:Viсtor G:irtnеr,С. von.184 P|lапzeпrеiсh' S Iltis,Мrs. H. 1954.( 2ЗI*2З4. Reprt Сhiсago:Univе olЬy, R. 1985.orig orеl, V. 7996' Grеgс Stеrn,С.' and Е. Shе Bсlo&.SanЕrаn .sИеiling, F. 1991.Нil Меdiсаl Gепеti www.MеndеlwеЬ. Еnglishand Gеr othеrs'thе follo Pаul' D. B., and praсtiсе,1900

Мeпdеl prеsеnt in thе hyЬrid plant whеn thе gеrm сеlls arе formеd suсh that gегm сеlls arе еithеr of onе kind or thе othеr, not miхеd. Thеn if in fеrtilization all сomЬinаtions of pollеn сеlls and еgg сеlls arе possiЬlе' populations of progеny of thе two kinds will Ье yiеldеd that will approximatе to thе statistiсalra.!Иhеrе unions аrе Ьеtwееn pollеn and tios that hе found in his ехpеrimеnts. forms arе rесovеrеd purе. Thus kind, originating сеlls of thе samе Ьoth еgg thе old idеa of onсе taintеd, always taintеd Was Wrong. Thе assumption that a nеw variant will simply Ье dilutеd Ьy rеproduсtion with thе normal form was also Wrong. Nеw сomЬinations of сharaсtеrsсan thus pеrsist. This was dirесtly rеlеvant to thе proЬlеm of thе sшсlmpirxgеffect of outЬrееding that Darwin had found dаunting for his thеory. Mеndеl's сonсеpt of gеrminal sеgrеgation is thus sееn in rеtrospесtas thе kеy that Darwin laсkеd. Also from sеgrеgаtionflowеd thе possiЬility of сomЬining hеrеditаry trаits in all sorts of сomЬinations and dеmonstrating that thе traits Ьеhavе indеpеndеntly of onе anothеr. Меndеl idеntifiеd thе sourсе of hеrеditаry variation with this proсеss of rеcombiпаtioп. TЬеreforе' hе oЬjесtеd to Darwin's сlaim that domеstiс animals and сultivatеd plants arе morе variaЬlе than thе ..сhangеdсonditions of сorrеsponding wild spесiеs Ьесаusе of thе еffесt of lifе.'' Instеad,hе optеd for thе grеatеropportunitiеs for сross-pollinations. Thе aссеptanсеof Меndеl's work in 1900 сamе along with an unсritiсal adhеrеnсеto nonЬlеnding сharaсtеrs' thus promoting skеptiсism toward thе сrеativе rolе of natural sеlесtion.If nеw сhаraсtеrsarе produсеd in onе nonЬlеnding StеP'thеrе is no spaсе for natural sеlесtionto aссumulatе slight diffеrеnсеslittlе by littlе. This matеrially dеlayеd thе intеgration of Меndеlian

Wasthus not Darwin's thеory Ьiologists'sеv:rman-spеaking nts of thе spесulativеtеaсhing thе suссеssivеdеvеlopmеnt of еd pеriod of timе. Onе of thе эortеda dеvеlopmеntal viеw of wаs a spесulativеphilos.16сеl ; of еxpеrimеnts. Mеndеl was rе Gеrman hyЬridists. His сhiеf ,ok Ехpеrimеnts аnd Оbsеruсt(Vеrsuсhе uпd B есlbа сh tuпgeп 849), found that fеrtilе hyЬrids 'еvеrtto onr or thе othеr of thе y Ь r i d st h а t e p p е a г е dt o r е m a i n thаt Mеndеl rеproduсеd many rt. Mеndеl Wеnt on to сhoosе rdе of forms found in thе wild. him in this dirесtion, it was not сult gеnus, as is oftеn assеrtеd. t oWеthеir multitudеs of spесiеs гhat hе had found in his сlassiс эхpеrimеnts Ьy suggеsting that 1urе)of thе diffеring potеntials

gеnеtiсsinto Darwinian thеory. BIBLIOGRAPHY

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Britainin thе еаrly yеars of thе .еsеntation of Mеndеl's first law,

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Batеson,!и. 1909. Мепdеl'sl,riпсiplеsof Hеrеditу' СamЬridgе:СаmЬridgе UnivеrsityPrеss. Еisеlеy,L. 1959.Dаrtaiп,sСепturу:Еuolutioп апd thе Меп Who Disссluеrеdlt. London:Viсtor Gollanсz. iпl йbеr diе Bаstаrderzеuguпg G:irtnеr,С. von. 1849. Vеrsuсheuпd Bесlbасhtuпgеп Pflапzепreiсh.Stuttgart:K. F. Hеrring. Iltis,tr4rs.H. |954. GrеgorМеndеl'sautсlЬiogrаphу. Joиrпаlof Неrеditу45: 2з1-2З4. Rеprintеdin R. olЬy, Оrigiпsof Мeпdеlism,2nd еd., |96_198. Сhiсago:Univеrsityof СhiсagoPrеss,1985. olЬy, R. 1985.origiпs of Меndеlism.2nd еd. Сhiсаgсl:Univеrsityof СhiсаgoPrеss. orеl, V. 1'996.GregorМепdеl:Thе First Gепеtiсist,Oхfоrd: Oхford UnivеrsityPrеss. Stеrn,С., and Е. Shеrwood'еds.1966.Thе Оrigin rlf Gепеtiсs:А МепdеlSourсе H. Frееman. BooA.San Franсisсo:.W. of Wеiling,F.1991. Нistoriсalstudy:JohannGrеgorМеndеl, 1822_1884.lсlurпаl Меdiсаl Gепеtiсs40: 1_2.5. Inсludеsthе Еnglishtехt of Mеndеl's186.5papеron Pisumin www.МеndеlwеЬ.
7.з1

7З2

Мiсbeпеr

Nliсhеnеr,Сharlеs D. (b. 1918) Chаrlеs Miсhеlrer, еntomologist at thе Univеrsit1'of Kansаs, is thе world's lеading ехpеrt ()n thе сlassifiсаtion,morphology, natural history' and еvolution of Ьееs,еspесially thе divеrsе sоlitzrryand priпritivеly soсirrlbееs whosе Ьiology сolltrаsts with tlrаt tlf thе familiar horrеylrее(Аpis tпеlliierсl). МtcЬ_ еnеr has usеd his Ьroad kr-rowlеdgеof thеsе insесts tO tеst idеas aЬout thе еvolution of insесt soсiеtiеsand to hеlp modеrnizе thе sсiеnсеof taxonсlmy. Не trr-rdhis marrу studеnts lravе trаvеlесl ехtеnsivеh. in thе Ur-ritеdStatеs, Afriсa, Asia' Еuropе, аnd Latin Amегiса to сtlllесt аnd oЬsегvе Ьееs irr thеir natural haЬitats.As a rеsult of this work thе Ьееsh:rvеЬессlmеа modеl taхtln for сompаrativе studiеs of еvolution. Мiсlrеnеr's rеsеаrсh is a prеmiеr еxапrplе сlf how еvolutionаr1,Ьiology usеs сullparativе studiеs of Ьеlrаvior and moгphology ttl undеrstаtrdthе origin of nеw trаits аnd tlrе divеrsifiсation сlf spесiеs.Bесausеt>fМiсhеrrеr'swf inforr-nаtiсrn that has Ьееn ехploitеd by a vеritaЬlе aге еnсyсlopеdiа еnеr and othеrs to traсе thе еvolution of suсh phеnomеna as parаsitism and thе transition from solitаry to soсial irr group-livinginsесts.His taхonomiс insight has nrаdе him а lеаdеr in thе tlrеorv anсl praсtiсе of s),stеmatiсs,tlrе str'rdyof сlilssifiсationaтrdrеlationshipsamong groups of organisпls.At thе agе of 81, Miсhеnеr puЬlishеd his magrrum opж.Гhe Bееs сlf thе World (2000), a 91Зpagе tomе that trеats 1,200 gеnеra arrd suЬgеnеriland moге than 16,000 spесiеs irr a r"rnifiеdсlassifiсаtiorrапd suпrmаrizеsmuсlr of thе сurrеlrt informatioп on this impсlrtant group' insесts tЬllt arе еssеrrtiаltсl есologiсаl and human сommunitiеs as pollinаtors of flowеring plаnts, inсluding many сrops. Мiсhеnеr's intеrеstin Ьееs Ьеgan whеn as а Ьoy lrе Ьеgan to сOllесt insесts Ьy lris mothег, an aпlаnеar lris homе irr southеrn Сaliforniа' Еl-rсtluragес1 tеur naturalist, and by P. H. TimЬеrlаkе, an authority оn Ьее taхonоmy, hе puЬlishеd his first еssay on Ьееs at thе аgе of 16. FIis сontagious еnthusiasm for Ьееs has inspirеd a largе numЬеr of studеnts and сollеaguеsirnd has put tЬе Univегsitу of Kansirs On thе map as a сentеr for Ьее rеsеilгсhand sсiеl-ttifiс lеadеrship. Miсhеnеr also wrсrtе importent еssays on thе taхonomу of Ьuttеrfliеs,although thеsе arе now lеss known than his work on Ьееs,and hе Was at thе сеntеr of сontrovеrsy during dеЬatеsovеr numеriсаl tirхonomy in thе l950s аnr'] l960s. Aloпg with RoЬеrt Sokаl, ц'hosе viеlvs wеrе sotllе_ w h a t п r o r е r a d i с a l , M i с h е l l е r a d v o с a t е d t h е u s е o f o Ь j е с t i v е ,q u a n t i t а t i v е datа in сlassifiсаtions (пиmeriсаl tахoнсlmу) as an antidotе tO somе of thе ovеrly intuitivе аrrd lеss sсiеrrtifiсpr
есologiсal геlationsl u n d е r s t a n da n d i n t с сount of thе nuп.lсг еnеr as ..irquiеt' gег polеmiсs...[Ьutli might s;lу dеadly.'' Miсhеnеr's сordia man of sсiеnсе,еspе hе has сondLlсtеdfiеl еntomologists in mu yеаrs Miсhеnеr Wаs Sсiеnсеs,onе of onl1 lristory whеn hе wa. Soсiеty for thе Studl pothеsis tеstingand Ьroad knowlеdgе of

BIBLIOGRAP

H u ] l ' D . L . 1 9 8 8 'S с l с M i с h е n е r ,с . D . l 9 6 з ' 12:1.51-172. |Ч/ч.

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200О.Тhе tsе '!7еst-ЕЬеrhаrd, M. J. : I n M . . [ .R у а n ,е d Inst Smithsоniirn

lvlillеr, StanlеyI

Stanlе,vL. Nlillеr spе vеrsity of Сalifоrnia Ьrеakthrough еxpеr sеarсh of pгеЬiotiс с gеthеr lvirh пlan1'с stеps and сhеmiсal с knсlrn,lеdgrnеnt of his of-lifе fiеld, ln \97З | to thе Natiсlnal Aсat his rolе in thе сrе:rti of t,ifе (ISSOL), thе Мillеr Awаrсl to Ье р In l9-52-1953,..v

and NoЬеl laurеatсF to simulatе thе сond ехpеrimеnts hе was on thе еtrlеrgеnсеof . . A l е k s a n d rI . o p а r :

Мillеr

.sity tlf Kansas, is thе world's 4v,natural history, аnd еvolu_ pгimitivеlystlсiаl Ьееs whosе lеvЬее /Аpls mеllifеrа). Miсhllsесtsto tеst idеas aЬout thе .nizеthе sсiеnсеof taхonomy. еr-rsivеly in thе Unitеd Statеs, 'llесtаnd oЬsеrvе Ьееs in thеir еs hаvе Ьесnomiсinsiglrt 4 irrsесts. iсе of systеm:ltiсs,thе study of эf orgаnisms.At thе agе of 81, еs of thе World (2-О0О), a 91З3еnеraand moГе than 16,000 эs muсlr of rhе сurrеrrtinftlrmаsеntialto есolсlgiсaland hurnаn inсluding many сrops. Ь r l yh е Ь е g a nt r l с o l l е с t i n s е с t s ragеd Ьy his nrotlrеr, an amаluthority сln Ьее taxonorny, hе t 6 . H i s с o n г а g i t l uеsn t h u s i i l s m n t s a n d с o l l е a g u е sa n d h a s p u t tеr for Ьее rеsеaгсhand sсiеntnt еssayson tlrе tахonomу of Lthan his wсlrk on bееs,arrd hе . . s( ) v е rn t r r n е r i с at аl x o n o m y i n lkаl, whosе viеws wеrе somе' u а n t i r a t iеr u s еr , f o h j е с t i v сq as аn аntidotе tO somе of thе s of thе timе. But hе аlso Ьеlе allowеd to sеparatе thе sysrrlvЬy knowing thеir Ьеhаvior,

есtlltlgiсalrеlatioпslrips,thе furrсt,ionsof thеiг r,аrious stгuсtI'lrеs'еtс., сan lrе ttr-rdеrstаtrd :rrrdintеrprсt tllx()llonliс data '' (Nliсlrеnеr l96З, 170). In al1 aсс o ш n t< l ft h е n u t l r е r i с i r l - t a x o n < l m wya r s , H r - r l l( 1 9 8 8 , 1 l 8 ) d е s с r i Ь е dМ i с h ..a rnеr as quiеt' !]еntlеman . . . who dсlеsrrot еnjoy partiсiPаting in rauсous p с l l е r n i с s . . . [ Ь u t l i n s с i е r r t i f i сс o m Ь a t [ h е i s I a l s o h i g h l y е f f е с t i v е ,s o m е might sаv dеadlу.'' Мiсhеnеr's сordial, unasslttrringmannеr lrаs madе hinr аn еffесtivе statеsmаn of sсiеnсе'еspесiаllyin сountriеs likе Jаpan, Мехiсo, and Brazil, whеrе hе hаs сonduсtеd fiеldwоrk and promotеd еntomologiсal rеsеarсh;and аmong еntor-пologists in tтusеums аnd laЬoratoriеs tЬroughout the world. For marry yеers Nliсhеnеr Was tlrе onlу Kаnsаs mеmЬеr of thе Nаtiorral Aсadеmy of Sсiеnсеs,onе of only two Karrsansto havе joinеd thе aсaсlеmyin its 184-yеar history whеn hе wаs еlесtеd in 1965. In1967 hе sеrvеd tls prеsidеnt of thе Soсiеtyfor thе Strrсlyof Еvolution. Miсhеnеr's сarееr shows thе valuе, for hypothеsistеsting and for thе undеrstandingof Ьiologiсal divеrsitv,of dееp arrd Ьroad knowlеdgе of a partiсLlli1rgrсlup of orgаnisms. B|вLloGRAPнY Hull' D. l-. l988. Sсiсllсеаs а Prtrсss,Сhiсagо:Urrivеrsity rlf СhiсаgоPrеss. М i с h с n е r , с . l ) . 1 9 ( l . ] . S o m с f r t t L l r еd е r . е l с l р m е n t s i n t i l х o n 6 m y . S , , s t е m а t i с Z с l r > l с t g 1 ,

12:151-172. |974, Тhе SсlсiаlBсеs' СаmЬridgе' MA: llаrvaгd Univеrsity Prеss. 2О0О. Тhе Bеes llf thе W;r/d. Bаltimorе:Johr.rsНopkins Univеrsity Prеss. Wеst-ЕЬеrhаrd,М. .l' 200.l. Thе inl;lortаnсеof taхon-сеntеrеdrеsеаrсhin Ьiologv. In N{' J. Ryаn, еr'1., Aпurап Ссlntпtltlliсаtiоп,З-7,.sИаshington,DС: -М..r.w._Е. SrnithsсlniаnIrlstituгionPrеss.

Мillеr, StanlеyL. (1930-2007) StanlеyL. Мillеr spеnt most of lris саrееr аs profеssorof сhепristryat thе Univеrsity of Сaliforniа, San Diеgo. [n thе еarly 1950s hе pеrformеd a sеriеsof Ьrеаkthrough ехpеrimеnts that signalеd thе Ьеginning of thе systеmatiсrеsеarсh of pгеЬiotiс сhеmistry аnd thе еmеrЕ]еnсе of lifе. From thеn on, togеtlrегwith many сollеaguеs arrd studеnts, Nlillеr invеstigatеdthе possil.llе stеps and сIrеrтiсalссlmp
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Мillеr сontainеd in sеparatеflasks сonnесtеd Ьy tuЬеs a miхturе of gasesпrimiсking thе еarly hydrogеn-riсh (rеduсing) atr-nosphеrеaгrd watеr rеpгеsеntingthе oсеan. As an еnеrgy sourсе hе еmployеd еlесtriс сJisсhargеsthat stood for lightning. Aftеr running thе ехpеrimеnt for а wееk, Millеr analyzеd thе aquеous solution-1[g ..9g6nn''-fg1 thе dissolvеd produсts of thе intеraсringatmosphеrе'sсonstituеnts.Hе found aЬundant synthеsisof оrganiс ссlnrpotlnds, inсluding amino aсids, thе Ьuilding Ьloсks of pгotеins. Signifiсantly' thе rеsults wеrе not statistiсallyrandom: Only a small numbеr of Ьiologiсallу rеlеvant organiс сompounds wеrе produсеd in high yiеlds in thе ехpегimеntout of the vast nlrmЬеr of potеntially rеlеv:rntorganiс suЬstаnсеs'Glyсinе and alatrinе,thе rrrostсommon amino aсids ir-rprotеins, wеrе thе rrrajorproduсts. In work pеrformеd Ьy Мillеr and otlrеr rеsеarсhеrsin thе 1970s, it wаs found that thе samе amino aсids and in thе samе rеlativе quantitiеs wеrе oЬtainеd whеn thе сontеnt of mеtеoritеsthat rе:rсhеdеarth wtrs analyzеd' Sinсе mеtеoritеs arе сonsidеrеd геliсs of thе formatiorr of thе so[ar planеts,thеir organiс сontеnt пraу indiсatе that сhеmiса| proсеssеssirnilar tсl thе Мillеr rеaсtions wеrе сommon in thе solirr systеm. Similar ехpеrimеnts Ьy othеr сhеmists dеmonstrаtеd thе synthеsis undеr prеЬiotiс сonditions of sеvеralсonstituеntsоf nuсlеiс zrсids'for ехirmplе,thе nitrogеn Ьаsе аdеninе. Мorе rесеntly thе ехistеnсеof a prinrordial hydrogеnriсh atmosphеrе that еnaЬlеd organiс synthеsis lras Ьееn quеstionеd' and many rеsеarсhеrs postulatе instеad that organiсs wеrе importеd to еarth from spaсе Ьy сomеts, mеtеoritеs,and dust partiсlеs. Мillеr nеvеrtlrеlеssЬеliеvеd that сonditions for organiс synthеsis on еarth might hаvе ехistеd. Using а more potеnt high_еnеrgysollrсe' Мillег suссееdеdin dеmonstrating, Ьеginning in rhе 1980s, tl-rеsynthеsisof amino aсids аnd nuсlеiс aсid Ьasеsin a gas miхturе that was lеss rеduсing thаn his 1953 ..irtmosphеrе.'' Мillеr Was a promotеr of thе gеnеtiс сonсеption
C с l n s е q u е r t t l yM ' i llеr. t o t h е s е а r с hf o r t l l е с o thеsizе and that сoulсJ Sеvеral suсh сandidatе T t i s i m p o r t a n tr o n o l o f l i f е w а s r i g h t l yl i n k . planеts. Aftеr thе founс tion (NASA) in 1958, t h е е s t а l l l i s h m е not f r I Sеvеralof Мillеr's latег tеntiаl for prеЬitltiс сh p r е v a l е n to n o n е o f J L moons. ln ordеr to disсгеd rеly on thе еmpiriсal d Ь i o t i с s с е n a r i o se t l d . l faсеd Ьy rеsеаrсhеrs., m o t i n g i g n o г а n с еа Ь о t h е p г o h | е r no f r h е е m t

BIBLIOGRAPHY

F r у . I . 2 0 0 8 .М i l l е r ,S t а г Bitlgrаphу.vo|.,5,l, М i l l е r 'S . I . l q . 5 3A. P r r сonditioпs.Sсiепсе|

}vlimiсry

N4imiсry oссurs rvhеn and, tlrrough that геsе iсry is а strikingphеn r o | еi n е v o l u t i o n a r Ь yi t i o n , а n d s е v е r а с| h а l l с s y s t е m sr е m а i n t o l . е s Мimiсrу is гаmpаn simplеst form, mimiсr' s с m Ь l е si V е r y d i f f е г е aggгеssivеnlinliсгv.wl. that rеsеmЬlеsthе fоod o f a n a I l i g e t o гs n а p p i е a t i n gf i s h i n t o t h е r u r r wеll_knowrrеxamplеs еfit to its ownеr and tl t h е o г g а n i s mЬ е i n gi m Thе morе сompliсa Ь I е sa s i r r l i l а o r n е ,a s i

Мimicrу s a miхturе of gasеsmimiсking rе and Watеr rеprеsеnting thе :triс disсhargеs that stood for rееk,Мillеr analyzеd thе aquе. p r o d u с t so f t h е i n r е r a с t i n gа t lnthеsisof organiс сompounds, protеins.Signifiсаntly,thе rеall numЬеr of Ьiologiсаlly rеlе4h yiеlds in thе еxpеrimеnt out ganiс suЬstanсеs.Glyсinе and геins,wеrе thе major produсts. :hеrsin thе 1970s, it was found lativеquаntitiеswеrе oЬtainеd arth Was anаlyzеd.Sinсе mеtеt h е s o | а rp | a n е t st,h е i r o r g а n i с similar to thе Millеr rеaсtlons ronstratеdthе synthеsis undег nuсlеiс aсids, for ехamplе, thе еnсеof a primordial hydrogеnэsis has Ьееn quеstionеd' and aniсs wеrе importеd to еarth artiсlеs.Мillеr nеvеrthеlеssЬеon еarth might havе ехistеd. in dеmonstrating, еr suссееdеd ' aсids аnd nuсlеiс aсid Ьasеs in 1953..atmosphеrе.'' еption сlf thе origin of lifе' aсmol f o r е m l l s ts е l f - r е p l i с а t i n g ost fundamеntalquеstion that еnеtiсmatеrial thаt сould havе primitivе living systеm. Millеr rе fiеld that a watеrshеd in thе саlworld in whiсh RNA molеrs сatalysts.Thе idеa that RNA эry еarly in thе еvolution of lifе -еsliеorgеl, Franсis Сriсk, and r wаs thе solе playеr in thе vеry l s a f t е rt h е s u г p r i s i n gd i s с o v е r y i'NA molесulеsthat in addition ; сarrying out thе funсtion that y by protеins. vеvеr'Millеr, as wеll as his сolсamе сonvinсеd that lifе сould alizеdthat thе prеbiotiс synthе: itsеlf was highly improЬaЬlе.

Сonsеquеntly, Мillеr's rеsеarсh from thе 1990s until his dеаth was dеvotеd to thе sеаrсh for thе сonstituеntsof a prе-RNA world that wеrе еasiеrto synthеsizеand that сould havе еvolvеd into thе сonstituеntsof thе RNA world. Sеvеralsuсh сandidatеswеrе suggеstеdЬy Millеr аnd his group. It is important to notе that from its inсеption Мillеr's rеsеarсh on thе origin of lifе was tightly linkеd to thе widеr сontеxt of thе sеarсh for lifе on othеr planеts.Aftеr thе founding of thе National Aеronautiсs and Spaсе Administration (NASA) in 1958, thе young Millеr Was among thе main сontriЬutors to thе еstaЬlishmеnt of thе fiеld of ехoЬiology, latеr to bе сallеd astгoЬiology. Sеvеralof Millеr's latеr ехpеrimеnts lеnt сrеdеnсеto thе hypothеsis that thе potеntial fоr prеЬiotiс сhеmistry еxists bеyond еarth, pеrhaps undеr сorrditions prеvalеnt on onе of Jupitеr's moons' Еuropa' and possiЬly on othеr Jovian moons. In ordеr to disсredit thе study of thе еmеrgеnсе of lifе, сrеаtionists oftеn rеly on thе еmpiriсal dеЬatеsamong origin-of-lifе sсiеntistsovеr spесifiсprеbiotiс sсеnarios and on thе many thеorеtiсаl and еmpiriсal diffiсultiеs still faсеd Ьy rеsеarсhеrs.Millеr, who strongly dеnounсеd сrеationists for promoting ignoranсе аЬout sсiеnсе' nеvеr doubtеd that a сhеmiсаl solution to thе prоЬlеrn оf thе еmеrgеnсеof lifе will еvеntually Ье found. в|вLIoGRAPHY Fry' I. 2008.Мillеr' StаnlеyLloyd. In N. Koеrtgе'еd.,Nez Diсtioпаrуof Sсiеntifiс Sons. Bbgrаphу,vоl. 5, 154-158.Dеtroit:СharlеsSсriЬnеr's Мillеr, s. L. 1953.A produсtionof amino aсidsundеrpossiЬlеprimitivееаrth -l.F' сonditions.Sсiеnсе1'17:528-529.

Мimiсry Mimiсry oссurs whеn thе fеaturеs of сlnе spесiеsrеsеmЬlе thоsе сrf anothеr and, through that rеsеmЬlanсе,сonfеr somе advantagе on thе mimiс. Mimiсry is a striking phеnomеnon in naturе; its study has plаyеd an impoгtant rolе in еvolutionary Ьiology from thе еаrliеst argumеnts aЬout nаtural sеiесtion, and sеvеralсhallеngingpuzzlеs about thе еvolution of сomplех rnimiсry systеmsrеmain to Ье solvеd. М i m i с r y i s r a m p a n t i n n a t u r е ( s е еW i с k l е r 1 9 6 8 ; R a n d a l l 2 0 0 5 ) . I n i t s simplеst form' mimiсry oссurs whеn a partiсular fеaturе of onе organism rеsеmЬlеs a vеry diffеrеnt organism. Thе most familiar еxamplеs arе сasеs of aggrеssivеmimiсry' whеrе a prеdator luгеs its prеy with a pаrt of its оwn body that rеsеmЬlеsthе food of thе prеy. Thе flеshy rеd protuЬеranсе on thе tonguе of an alligator snapping turtlе mimiсs a Ьloоdworm and lurеs Ьloodworm. еating fish into thе turtlе's mouth. Thе lurеs of anglеrfish and Ьatfish arе othеr wеll-known ехamplеs. In thеsе сasеs' thе mimеtiс fеaturе сonfеrs a сlеar Ьеn. еfit to its ownеr аnd thе еvolutiоn of thе fеaturе сrеatеs no disadvantаsе for thе organism Ьеing imitatеd. Thе morе сompliсatеd fсlrm of mimiсry oссurs whеn onе organism rеsеmЬlеs a similar onе' as in onе Ьuttеrfly rеsеmЬlinganothеr' Ьut ш'ith thе twist

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Мimiсrу thаt thе rеsеmЬlanсеoffеrs a Ьеnеfit to thе mimiс ЬLlt а potеntial disadvantagе to thе nrodеl (thе organism Ьеing imitatеd)' This happеns whеn modеl and mimiс havе vеry diffеrеnt сl.laraсtеristiсsor есologiсal rolеs and thе suссеss of thе mimiс thrеatеns thе modеl. For ехamplе' on сoral rееfs in thе Paсifiс, small fish сallеd ..сlеanеr wrassеs'' find food Ьy piсking сrrrstaсеan есtoparasitеs from thе sсalеs of largеr fish, whiсh visit spесifiс spots on thе rееf whеrе thе wrassеsoссur' Thеrе is anothеr spесiеsof small fish, a Ьlеnny, that mimiсs thе shapе and сoloгation of thе сlеanеr Wrassе Ьut, гathеr than piсk parasitеs from thе largег fish, takеs small Ьits from thеir tail fins. Thе blеnny's mimiсry of thе wrаssе allows it to сlosе in on its targеt whеn it might n of Ьiologists whеn hе dеsсriЬеdhow сеrtain Amazonian buttеrfliеs in thе family Piеridaе Ьorе а striking rеsеmЬlanсе to unrеlatеd Ьuttеrfliеs in thе family Неliсoniidaе. Batеs had notiсеd that thе hеliсoniid Ьuttеrfliеsflеw languidly yеt wеrе rarеly attaсkеd Ьy Ьirds, whilе thе piеrids flеw m
fеnding food itеm. It of a palаtaЬlе spесiе nеss through a rеduс lowеr risk of prеdati mimiс and modеl zrrе Dеspitе thе simpliс еrаl iпrpoгtаnt qLlеst sian mimiсs must rе morе mimiсs thaп m rathеr than thе rеvеr darrсеs of modеl anсl as thе modеl foг sе pipеvinе swallowtail Sесond, if Batеsia gеnеs that сontrol pа struсtions for thе pa thе alphabеtiсalеntrу that thosе gеnеsаrе i: the faсt that tlrеrе is hеritanсе of mimеtiс gеnеs of largе еffесt gеnеs wеrе oЬviousl trastеd with thе Darц was thе сumulativе il disputе was сlarifiеd сonсеrtеd inhеritanс pattеrns and thе еffе сor-rtrolling gеnеs (sе nеw rеsеarсh lrersrеv е t a l . 2 0 0 8 ) ,t h е е v o l linkеd сomplех tlrat i Thе dеsсription of whеn diffеrеnt popr.r looking modеls in di iпg pattеrn within thс is starting to rеvеаltl Third, thе study o unpalataЬility and tс that a prеdatоr wor. must diе so that thе samе appеaranсе en sprеad via thе сlass gеstеd a kin-sеlесtion mzrny toxiс Ьuttеrfliе and otlrеrs сitеd thеrс ity and warning сolo

МЙпicrу LimiсЬut a potеntial disadvanэd).This happеns whеn modеl эr есologiсal rolеs and thе suс_ rmplе, on соral rееfs in thе Pad food Ьy piсking сrustaсеan 'hiсh visit spесifiс spots on thе .spесiеsof small fish, a Ьlеnny, :lеanеrwrassе Ьut' rathеr than ll Ьits fгоm thеir tail fins. Thе sе in on its targеt whеn it might l. But onе might ехpесt thе an:d from its tail will provokе lеss d impеril thе wгassе'saЬility to :nсеof this mimiсry systеm' wе 'dеl and nrimiс on еaсh otheг's эffесtsarе Ьalanсеd. ;tеmsarе thе hundrеds of сasеs tatеd Ьy harmlеss оr palаtaЬlе :сiеsgains its advantagе through ation bеtwееna visuаl or olfaсеn assoсiatеthat сuе with thе llving palataЬlе Ьuttеrfliеsthat s (1862)Ьroughthis phеnomе; с r i Ь е dh o w с е r r a i nA m а z o n i а n g геsеr-rrЬlanсе to unrеlatеd Ьut_ notiсеd that thе hеliсoniid Ьut[ Ьy Ьiгds,whilе thе piеrids flеw posurеto Ьirds. Тhе hеiiсorriids piеrids aге nontoХiс and palattiс dеmonstrationof thе powеr rgеgainеd by an individuаl of a :hosеof a noxious spесiеs that ;еstions'еvоlutionary Ьiologists udyirrgthе naturе and еvolution Jamеthе аpprесiationthat mimt, thе study of mimiсry сamе to )gy as а modеl systеm for undеrln that сould mold сomplеx pat'd into thrее typеs. In Batеsian lmЬlеsa dangеrous or unpalat_ rnd how thе prеdator lеarns to nе Ьесomеsill and vomits, aftеr void prеy that rеsеmЬlе thе of-

fеnding food itеm. It is also not diffiсult tо sее Batеs'Sargumеnt that a mutаnt of a pаlаtaЬlе spесiеsthаt rеsеmЬlеsiln unpаlatzrЬlеonе will havе highеr 6tnеss through a rеduсеd risk of prеdatiоn. If a Ьеttеr rеsеmЬlanсес
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Мimiсrу argumеnt сannot Ье сorrесt. Othеr hypothеsеs havе Ьееn suggеstеd, Ьut thе proЬlеm rеmains unsolvеd. Thе sесond typе of сomplех mimiсry is сallеd Мiillеrian mimiсry' whiсh dеsсriЬesthе rеsеmЬlanсеof two or morе unpalataЬlе or danр;еrousspесiеs to еaсh othеr. This pattеrn was аlso dеsсriЬеd Ьy Batеs, who oЬsеrvеd that many tropiсal Ьuttеrfly spесiеs formеd mimiсry rings in whiсh a group of spесiеs ехhiЬitеd a сommon mimеtiс pattеrn. Furthеr, Batеs oЬsеrvеd that suсh pattеrns сhangеd in wholеsalе fashion from onе gеographiс arеa to anothеr. Sеvеral spесiеs within thе gеnus l]eliсoпiцs in thе Amеriсan trоpiсs offеr onе of thе Ьеst.doсumеntеd сasеs of a mimiсry ring. Miillеrian mimiсry and mimiсry rings posе a numЬеr of pеrplеxing quеstions.Thе advantagеоf a mutual resеmЬlanсеof unpalataЬlе spесiеsis сlеar at first; if a сеrtain numЬеr of individuals mrrst diе to tеaсh prеdators to avoid a pattеrn, thеn if that numbеr is dividеd Ьеtwееn two spесiеs, thе risk of prеdation is lowеr for individuals of еaсh spесiеs,and a mutual геsеmЬlanсеwill еvolvе. Of сoursе' thе proЬlеm of how toxiсity еvolvеs in thе first plaсе still еxists Ьесausе this argumеnt bеgins onсе two spесiеs arе еaсh tохiс. And although many ехplanations havе Ьееn suggеstеd, it rеmains unсlеar why mimiсry rings сhangе thеir pattеrns aЬruptly еvеry fеw hundrеd milеs. Thе third typе of сomplех mimiсry is thе most puzz\ing. In thеsе сasеs all thе spесiеsinvolvеd arе tохiс or dangеrousЬut thеy vary suЬstantiallyin that noхiousnеss.This makеs thе rings diffiсult to dеsсriЬе as еithеr purely Batеsian сomplехеs or purеly Miillеrian rings. Thе most spесtaсularof thеsесasеs might Ье thе mimiсry group that inсludеs thе dеadly сoral snakеs of tropiсal Amеriсa and a sеriеsof mildly vеnomous spесiеsthat sharе thе Ьrightly Ьandеd сolor pattеrn. Thе diffiсulty in ехplaining this pattеrn is that a Ьitе from thе еx. trеmеly dеadly сoral snakе kills most would-bе prеdators, and dеad prеdators сannot lеarn to avoid what killеd thеm. Two ехplanations havе Ьееn offеrеd for this typе of mimiсry ring. In thе first еxplanation, сallеd Меrtеnsian mimiсry' thе mildly noхious spесiеsis in faсt thе modеl from whiсh prеdators lеarn and thе dеadly spесiеs is thе mimiс, thе rеsеmЬlanсе Ьеing favorеd Ьy thе faсt that attaсk гаtеs on thе dеadly animal dесrеasеas pгеdators lеarn from thе lеss dеadly еnсountеrs. Thе sесond ехplanаtion, сallеd quasi-Batеsianmimiсгy, rеvеrsеsmodеl and mimiс and postulatеs that thе mildly noxious spесiеs mimiсs thе highly noxious onе. This hypothеsis was dеvеlopеd for Ьuttеrfly rings in whiсh spесiеs variеd in aЬundanсе, as wеll as toхiсity' thе mildly toхiс spесiеs Ьеing thе rarеr. Thе rеlativе aЬundanсеs rеsеmЬlе thе argumеnts about modеl and mimiс aЬundanсеs that еmеrgе from purеly Batеsian mimiсry, hеnсе thе namе quаsi-Bаtesiап. TЬe mесhanisms positеd for quasi-Batеsian mimiсry involvе vеry spесifiс argumеnts aЬout how animals lеarn, inсluding argumеntsaЬout whеthеr lеarning is pеrmanеnt and how long lеarning lasts without rеinforсеmеnt (sее Мallеt and Joron 1999 for a dееpеr disсussion).Thеse opposing еxplanations rеmаin to bе rеsolvеd (Mallеt 2001). Тhе study of mimiсry еpitomizеs еvolutionary Ьiology as a disсiplinе. Simplе mimiсry is rеadily oЬsеrvеd Ьy еvеn a сasual natural historian and

Ьеgs thе quеstiotl Ot i n s p i r е d е е p е rq u е s of sophistiсatеd rеs work in gеnеtiсs, d and сomputational stoгy, undеrstandin to unfold.

BIBLIOGRAP

BаtеsH , . W . 1 8 6 2 .С о Тrапsасtirlпsof t| Bеltran,M.' С. D. Jigg pollеnfееding,pu НеIiссlпiusЬttсr1 BiologiсаlJourпа Сlark, R', S. М. Brorv 2008. Сolour pat Thе transсriptio Proсееdiпgstlf th Кronforst,M. R., аrrd divеrsityin HеIiс S е r i е sB 2 7 5 : 4 9 3 M а l l е t 'J . 2 0 0 1 .С a u s mimiсry.Еuolutk N4allеt,J., аnd M. Jоr Polymorphismss З аnd Sуstеtпаtiсs N i j h o u t ,H . F . 2 0 0 З .I сl Ьig еffесts,ar"rd R a n d a l l , . JЕ. . 2 0 0 5 .A 299-328. .!7iсklеr' !7. 1968.Мil

IyIоdеrnrеptilеs

Rеptilеs сonstitutе с groups of tеtrapod ( ing rеptilеs rangе in 1 gram to saltwatеr оvеr 1,100 kilogra livе-Ьеaring and еp (warm-Ьloodеd),ma most of thе есologi tеtrapods. Somе cf еxаmplеs аЬound o Ьеaring and thс ot} сontrovеrsiеs in rеpt gгoup' and in partiс ..Birds''in iсal еntry

Мсldеrп Rеptilеs :s havе Ьееn sr.rggеstеd, Ьut thе llеd Mijllеrian mimiсry, whiсh p а l a t a Ь l еo r J a n g е r o u s s p е с i е s d Ьy Batеs,wlro oЬsеrvеd that сry rings in whiсh a group of L. Furthеr, Batеs oЬsеrvеd that .om onе gеographiс arеa to an.,.lпiusitt thе Amеriсаn tropiсs i m i с r yr i n g . M i i l l е r i а n m i m i с r y ng quеstions.Thе advantagе oI s с l е a ra t f i r s t ;i f a с е r t а i n n u m ; to avoid a pattеrn' thеn if that isk of prеdation is lowеr for innЬlanсеwill еvolvе. Of сoursе, :st plaсе still ехists Ьесausе this ,хiс. Anсl although rnany еxplalеar why mimiсr1' rings сlrаngе lеs. rrostpuzzlirrg.In thеsе сasеs all lt thеy vаry suЬstantiallyin that l с{еsсriЬе as еithеr purеly Batеэ most spесtaсularof thеsе сasеs : dеаdlyсoral snakеs of tropiсal еs that shаrеthе Ьrightly Ьandеd pattеrnis that а Ьitе from thе еx_ lе prеdators,aпd dеad prеdators his typе of minriсry ring. In thе , t h е m i l d l yn o х i o u ss p е с i е si s i n r ar-rdtlrе dеadly spесiеs is thе rе faсt thаt attaсk ratеs on thе гom thе lеss dеadly еnсountеrs. rn mimiсry, rеvеrsеsmodеl and s spесiеsmimiсs thе highly noxЬuttеrflyrings in whiсh spесiеs э mildly toxiс spесiеs bеing thе Lе nr$uПеntS aЬout modеl and atеsianrnimiсry, hеnсе thе namе quasi-Bаtеsianmimiсry involvе :arn' inсluding argumеnts aЬout lеarning lasrs without rеirrforсе_ l е r d i s с r r s s i o n )T.h е s е o p p o s i n g

001). ionary Ьiology as a disсiplinе. a с a s u а ln a t u r a l h i s t o r i a n a n d

Ьеgs thе quеstion of its origin аnd пraintеnаnсе.Сrlmplех mimiсry systеms inspiге dее;lеr quеstions' whiсh lravе provokеd nеarly a сеntury alrd a half of sopЬistiсiltеd геsеaгсh, from Batеs's сlriginаl oЬsегvаtitlns to modеrn work in gеnеtiсs, dеvеlopmеnt, есology, nеuroЬiology, and mathеmatiсal аnd сomptrtаtiсlnаl modеling. Wlrilе tlrе disсovегy of mimiсry is аn old story, undегstandingits еvolution is vеry muсh a nrodеrn onе that сontlnuеs to unfold. в|BLIoGRAPHY Batеs,H. !(/.1862.СontriЬutionstrl an insесtfaurlaof thе Amazon Vallеy. 7'rапsасtitlпs сlf thе l-iпп,tсапStlсiеtусl|-Loпllсlп 2З: 495_566' | J е l t r a nМ, . , с . D . J i g g i n s^ , . v . Z . B r o w е rЕ , . B е r m i n g h а ma,n d J . М а l l е t .2 0 О 7 . D o pollеnfееding,pupаl-rrrаting anсllаrr,аIgгеgariousnеss hаr',е а sirrglесlгiginin HеliсoпiusЬuttеrfliеs? Infеrеnсеs from mrrltiloсus DNA sеquеnсе data. jourttаlсlftbе ]'iппеаnSllсiat1, Blrllсlgiсitl 92:121-239, Сlark, R.' S. М. Brown,S. С. Сollins,С. D. Jiggins,D. G. Hесkеl,and A. l).Voglеr. 2008.Сolоur раttеrnspесifiсatiorr in thе Moсkеr swаllowtаilPа1liliоdсlrdаnus: Tlrе trarrsсriptiоn faсtorinvесtеdis a саndidatеfor thеmimiсryloсusI{. Prосееdiпgs o|.thеRoltаlSсlсiеt1t of l'oпdoп, SeriеsB 275: 1181-1188. Кronfоrst'N{.R., :lndt,. Е. GilЬеrt.2008.Thе рopulatiсln gеt-tеtiсs of mimеtiс divеrsityln HeliсопiusЬuttеrfliеs.Proсесdiпgsof tbс Roуаl Soсiеtуof Loпdсlп, SеriеsB 275:49З_5(|0. Маllеt,J,2001. Саusеsаnd сonsеquеnссs of a laсk сlfсoеvоlutionin Мiillеriаn l t l i r n t с г r L' .t l l l t t ! i r ' t t . t r Е у с ,l l , l 9 1 ,I j : , 7 - - . У 0 ь . Маllеt,.}.,аnd М. Joron. 1999' Еvolution of divеrsity in warrring сolor and mimiсry: PolymorpЬisms, shifting Ьalanсе,аrld sресiаtitlt-t. ,Aппuаl Rеt'iеlt', гlf Есolog1, сtпd Sуstemаtiсs 30: 2,01_2.]3. Nijhout, H. F. 2003. Polvmorplriс minriсrv irl Pаpilio dаrt]апus:Mosаiс doпrinanсе' Ьig еffесts,and origins. Еuсllutioп апd Dеuеklpmеnt 5: 579-592. Itandall,J. Е. 2005. A rеviеw сlf mimiсry in пrаrinе frsЬes.Zorllсl.чiсаlStudics 44:

299_З28. Wiсklсr,W. 1968.Мimiсrу.Londot-t: Wеidеnfеldand Niсolson.

-rT

Мodеrn rеptilеs Rеptilеs сonstitutе tlnе of tlrе most mсlrphologiсally arrd есologiсally divеrsе grоups of tеtгapod (fouг-lеggеd)vеrtеЬrаtеs.Thе roughly l6'000 spесiеsof living rеptilеs rangе in Ьсldy sizе from tiny lizards and snakеs that wеigh lеss than 1 granr to sаltwatеrсroсodilеs that rangе up to nеarly 7 mеtеrsin lеngth and ovеr l,100 kilograms in wеight. Thе living rеptilеs inсludе spесiеsthat аrе livе-Ьеaring and еgg-lаying, есtothеrmiс (сold-Ьloodеd) anс.l еndothеrrrriс (warm-Ьloсldеd),marinе аnd tеrrеstrial,lrеrЬivorous and prеdaсеous-in short, most tlf thе есologiсal, physiоlogiсal' arrd morphсllogiсаI r.аriation found in tеtrapоds. Sornе of this variation сan Ье ехtrеmеly laЬilе еvolutionarilyехanrрlеs aЬоrrnd of piriгs сlf сl
7.з9

740

Мoderп Rе1ltiles еxpеrts would agrее on is ..thе most rесеnt сomпlon anсestor of a turtlе, ir snakе, a |izard, and а сroсodilе, and аll spесiеsdеrivеd from that anсеstor.''If that dеfinitiotris usеd' the living rеpdlеs inсludе lizагds, snakеs, amplrisЬaеnians (a group of limЬlеss,lizагdlikе arrimals),rhynсhoсеplralians(tЬеtuаtarаs)'сroсodilians, biгds, and turtlеs. It also inсludеs a grеat variеty of ехtinсt linеagеs, inсluding thе marinе iсhthyosaurs and plеsiosaurs, thе flying ptеrosaurs, and (lizаrd-hippеd) thе еvеr-popr-rlar ornithisсlrian (Ьird-hippеd)and sа.rtlrisсhian dinosaurs (sееtlrе alphaЬеtiсal еntry ..Г)it-tosauгs: Thе n-rodеlsystеrnfсlr еvolution'' in this volumе). Phylogеnеtiсally thе living rеptilеs arе oftеn split into thrее primary linеagеs. Thе lеpidosaursinсludе thе lizards, snakеs,amphisbаеnians,and ttlatarasand аrе thе numеriсаlly dсltninirntgroup of nonaviаn геptilеs.Arсhosaurs inсludе сroсodiliarrsand Ьirds, аs wеll as a vast divеrsity of еxtinсt spесiеs,inсludiпg thе traditional dinosaurs. Finally, thе tеstudinеs (sornеtimеsalso known аs thе сhеlonians)inсludе thе turtlеs аnd tсlrtoisеs,а small group of mсlrphologiсally uniquе vеrtеbrаtеs.Amсlng rеptile Ьiologists onе of tlrе kеy rесеnt rеsеarсh еf_ forts has foсusеd on lrtlw thеsе majoг groups arе rеlatеd to еaсh othеr, аlrd whаt thеsеrеlationshipstеll us аЬout thе history of divеrsifiсationof tеtrapоd vеrtеЬratеs. Turtlеs arе oftеn сonsidеrеdthе m
Thе lеpidosallrs arе Thеy inсludе two grol lizardlikе spесiеs rеstr thе -7,000 spесiеs of tivеly сallеd thе squarn tropiсal rеgions, altho massеs ехсеpt polar ; uЬiquitous and pеrsist pеatеd еvolutionаry lс plеtе limЬlеssnеsshas group. Thе most fam .With nеarly 3,000 livi of limblеss squamatеs thе skinks. othеr imp of сomplеx vеn()пl sys сomplехity and prесis ifiеd skull and tееth all dirесtly inttl prеy with maxillary Ьonе; whеr

mourh. Finally, thе living a hеrе) and thе 22 livin

Thе pinе snakе,Рitиop irrЬаЬitsthе pinе forеs snak Nеlv Jеrsеy.Pir-rе witlr gophеr tortoisесс rеptilеs'with nеarly3'( fеаturеsinсluding'irrп injесtingvеnom intсlpt

Мсlderп Reptilеs 741 ommol] anсestoГ of a turtlе, a ' dеrivеd frorn thаt anсеstor.'' If lizards,sltakеs'аmphisbaеnians oсеphalians(tlrеtuataras),сroсlrеatvariеty of ехtinсt linеagеs, auгs' thе flying ptеrosaurs, and аnd saurisсhiаn(lizard-hippеd) rs: Thе modеl systеlт for еvolusplitinto thrее;lrimаг,vlirrеagеs. irnd tuаtаras and lphisЬirеnizrns, ian rеptilеs.Arсhosаurs inсludе sity of еxtinсt spесiеs'inсluding :s (somеtimеsirlso known as thе small group of morphologiсally nе of thе kеy гесеnt rеsеarсh еf; arе rеlаtеd to с'aсh othеr, and tlf tеtrapod lry of divеrsifiсatior-r tivе gror.rpоf rеptilеson thе Ьаt opеning (or apsе) in thе сhееk ammalsаnd thеir rеlativеshavе ds),and all otlrегrеptilеs havе a ;ids).on thе Ьasis of thеir еxэn that thе anаpsid сondition is , turtlеshаvе oftеn bееn сonsidom thе othеr rеptilеs' Howеvеr, indiсatеsthаt trrrtlеs,whilе сеrr forrrrof m
Thе lеpidosaurs аrе thе most divеrsе and nunrегous of thе living rеptilеs' Thеy inсltrdе two !.roups: thе morplrologiсally primitivе tuatаras (a pair of lizardlikе spесiеs rеstriсtеdto sеvеral сlffshoreislands in Nеw Zеaland) and thе -7,000 spесiеs of lizards, snakеs, and thеiг rеlativеs (whiсh arе сolleсtivеly сallеd thе squamatеrеptilеs).Squamatеsаrе most divеrsе in thе world's tropiсal rеgions, although thеy oссur on all сontinеntal and most islаnd land massеs еxсеpt polаr and ехtrеmе high-еlеvation rеgions. Onе of thе most uЬiquitous and pегsistеntеvolutionary thеmеs in squamatе rеptilеs is thе rеpеatеd еvolutionary loss of Ьoth thе digits and limЬs; Ьy onе еstimatе сomplеtе limЬlеssnеsslras еvolvеd а minimum of 62 indepеndеnt timеs in thе group. Thе most fаmous еxamplе is thе srrakеs' or sеrpеnts (sее figurе)' !7ith nеarly З,000 living spесiеs'thеy arе Ьy far thе most suссеssfullinеagе of limЬlеss squamatеs)Ьut many othеr ехamplеs alэound,partiсularly aгnong thе skinks. Othеr important innovations in rhе squamatеs arе thе еvolr.ltion of сomplех vеnom systеms,whiсh rеасh thеir grеatеstlеvеl of morphologiсal сomplеxity and prесision in thе vipеrs and rattlеsnakеs.Неrе thе highly modifiеd skull and tееtlr :rllow injесtion of prесisеlу n-rodulatеdamounts of vеnt>rr-t dirесtly into prеу witlr a fang likе a hypodеrmiс nееdlеthat is attaсhеdto tlrе maхillary Ьonе; lvlrеn not in usе, tЬе fаngs сan Ье foldеd Ьaсk into thе mourh. Finally, thе living аrсhosaurs сonsist of thе Ьiгds (not сonsidеrеd furthеr hеrе) and tЬе 22 living spесiеs of alligators' сroсodilеs, and thеir rеlаtivеs.

Thе pinе snakе,Pituсlphismеlапсэlеuсrzs, a пrспtЬеrof thе сoluЬrid familу, inhaЬitsthе pinе fсlrеstsof thе southеrnUnitеd Statеsаnd thе Pinе Barrеnstlf Nеw Jеrsеy.Pinе snakеsЬurrow in sandy soil аnd arе o{tеnfound in assoсiltiоn with gophеrtortoisесoloniеs.Snakеsarе thе mоst suссеssfullinеagеof limЬlеss rеptilеs'with nеarly 3,000 spесiеs,and ехhiЬit a геmarkaЬlеrangеof аdaptivе fеaturеsinсluding',in rllany spесiеs(Ьut nоt pinе srrаkеs), a сomplеx systеmfoг injесtingvеnom iлto prеv irnd аttасkеrs.

742

Modеs of Spесiation Uniformly pеrsесutеdfor thеir skins аrrd rnеat,Ьy |970 aI|сroсodilian spесiеs on еarth wеrе сonsidеrеd thrеatеnеd or еndangеrеd Ьy thе Intеrnational Uniсln for thе Сonsеrvation of Naturе (www.iuсlr'org), an intеrnаtional organizаtion that r-tronitorsЬiodivеrsity dесlinеs.Howеvеr, Ьу |995 сonsеrvation еfforts around thе world had rеduсеdthis Ьy aЬout half, and as of this writirrg many spесiеSappеar to bе rесovеringto hеalthy population sizеs.Rеflесting thеir rеlаtivеly сlоsе phylоgеnеtiс rеlаtionship to Ьirds, сroс
-t{.8.s.

Nlodеs of Speciаtion (Мichaеl J. D. Whitе) A сommon misсonсеption among studеntsof sсiеnсеis that thеoriеs nrust Ье сorrесt to produсе progrеss in thеiг disсiplinеs.For ехamplе, studеntsmisundеrstand why thеy lеarn thе thеory of thе inhеritanсе of aсquirеd сharaсtеrs of Jеan-Baptistе Lamаrсk, rеmеmЬеring him only as ..thаt guy who Was Wrong about hеrеdity''' Howеvеr' that is a shortsightеdviеw: Lаmarсk prеsеntеda сomprеhеnsivеthеory of еvolution at a timе whеr-rthе proсеssеsweгe poorly undеrstood. Еvеn if his сontriЬutitln was imprесisе in dеtail, it positivеly influеnсеd our undеrstandingof еvolution today. With that in mind' it is a plеasurе to сommеnt on сytologist Мiсhaеl J. D. Whitе's сlassiс 1978 book Мodеs of Spесiаtioп.This book Was thе most сomprеhеrrsivеtrеatmеnt of spесiation until thе appеaranсеof Сoynе and orr's 2004 tехt. Тhе most famous aspесtof Whitе's Ьook is his еmphasison thе im-

portаnсе of сhromosorr -99% of сlosеly rеlatеd; tions, fusions' or othеr r a r r a n 8 е m е n t sa r i s е i s h i g nеwly arisеn rеarrangеm ish fеrtility whеn thеy :rr ularitiеs in mеiosis. Thl arrangеmеnts,thеir F l h' .!7hitе's viеw of и Alas' . h. in thе nехt l5 yеaгsT сonditions Wеrе nесеss.1 ing spесiаtion)whilе аls< arisеs (thе individuаl wh erozygotе). Еmpiriсаl w somеtimеs not as stеritе: fеrеnt ways in whiсh rеa rесombination) rаthеr th His еmphаsis on thе im1 planation for how tlrеyсl еvеr' thеrе аrе еХсеption a dirесt еffесt of a transl( .Whitе taсklеd sеvеr.rlс gaгding spесiеsdiffеrеnсе Еrnst Maуr's influеntiirlvi ation, during whiсh a lar1 lесtivе prеssurеsaftеr сolt of sympatriс spесiationin studiеd today in this сont ..еtho ours), he сгitiсizеd disсrimination and othеr ation. Instеad, hе suggеs in spесiation. Although h (2004) also notе thе ovеr natiolr whеrl thе rеlаtivеi hyЬrid proЬlеms iп s;.lес .\rhitе's tеxt is а riсhlу disсussions of еmpiriсa .!7hitе Was an outstаndi сonvinсеd that thе phеn spесiartion.AlthougЬ soп сan douЬt that this tех studiеs of spесiation.So many сontinuе to Ье асt ..And' at thе prеsе pliеs: а Ь o u t п l е r h o d so f s p е с i morе justifiаЬlеto gеnеr

Мodеs сrfSpесiation 74.] .,Ьу 1970 all сroсodilian spесiеs rdangеrеdЬy thе Intеrnational п w . i u с n ' o r g ) 'a n i n t е r n a t i o n a l inеs.Howеvеr,Ьу I995 сonsеrthis Ьy аbout half, and as of this to hеalthypopulation sizеs. Rеiationshipto birds, сroсodilians 'еstlеvеlsof parеntal сare of any ,olutionary Ьiology is ...Why did thаt many linеagеsof dinosaurs at thе еnd of thе Сrеtaсеous pе_ a mеtеoritесollision with thе 'logеnеtiсаlly,Ьirds aсtually fall l of dirrosaur.Thus in a vеry rеal е d i n o s а u г sd i d n o t g o е x t i n с г . иasa pеrfесtlygood dinosaur; so

DС: f thе Wоrld..!Иashington' Iуsterуfu Nаtиrе.Bеrkеlеу: R. Lawson.2004. Rеsolvingrеptilе markегs. In J. Сrасraftand M. J. ,, 45|467. Nеw Yоrk: Oхford lotusto thеЕuolиtioпrlf Diuersitу. Сrunrp'A. H. Savitsky'ar-rdK. D. JdlеRivеr,NJ: PеlrsonPrеntiсе -F1.8.S.

' Whitе) lf sсiеnсеis th:rt thеoriеs must Ье е s .F o r е x a m p | е s. t u d е n t sm i s u n rhеritanсеof асquirеd сharaсtеrs ..thatguy who was wrong only аs ;htеdviеw: Lamarсk prеsеntеd a ,whеn thе proсеssеswеrе poorly rprесisеin dеtаil' it positivеly inay. mеnt on сytologist i\4iсhaеl J. D. oп.This book was thе most сom. appеaranсеof Сoynе and Orr's 's Ьook is his еmphasison thе im_

portanсе of сhгomosomаl rеarrangеmеntsin spесiation. sИhitе notеd thаt -99Y. of сlosеly rеlatеd аnir-nalsdiffег by сhromosomal invегsions.trаnsloсa. tions, fusions' or othеr rеaгrangеп-lеnts,and that tlrе ratе at whiсh thеsе rеarrangешеntsarisе is high Ьy еvolutionary standards (1/500 individuals has a nеwly arisеn rеarrаngеmеnt)'Hе also notеd that most rеarrаngепlеntsdiminish fеrtility whеn thеy arе hеtеrozygous Ьесzrusеhеtеrozygosity induсеs iгrеgularities in mеiosis. Thus whеn divеrging populations сomе to diffеr in aгrangеn.lеnts' thеir F1 hyЬrids arе stеrilе,and spесiаtionhas tlссurrеd. Alas' \й/hitе'sviеw of пrcсhапiсаl сhromosсlmаl spеciаtioz fеll into disfavor in thе nеxt 15 yеars. Thеorеtiсal argumеnts showеd that ехtrеmеly stringеnt сonditiorrsWеrе nесеssaryfor thе fеrtility rеdr.rсtiontO Ье strong (hеnсесausing spесiatiсln)whilе also not еliminating thе nеw arrangеmеntwhеn it first arisеs (thе individual who first Ьеars this mutation will nесеssarilyЬе а hеtеrozygotе). Еmpiriсal woгk showеd that rеarrangеtnеnthеtеrozygotesаrе somеtirnеsnot as stеrilе as initially Ьеliеvеd.Instеad,studiеsnow suggеstdiffеrеntways in whrсh rеarre1ngеmеnts сontriЬutе to spесiation (е.g.,еffесtson .s7hitе. rесomЬination)rаthеr tharr tlrе dirесt fеrtiliry,геduсtiorrsdisсLrssеdЬy His еmphasis on thе importаnсе of rеarrangеmеntsWas сorrесt' Ьut his ехplanаtiorrfor how thеy сausеd spесiation is not widеly aссеptеdtoday. Нowеvеr' thеrе аrе ехсеptions: onе еlеgаrrtstudy of Sассhаrom1,ссsyеast showеd a dirесt еffесt of а transloсation on hyЬrid fitnеss(Dеlnеri еt al. 2003). Whitе taсklеd sеvеral otl.lеrсontеntious issuеs. Hе rеviеwеd gеnеtiс data rеgarding spесiеsdiffеrеnсеsarrd сonсludеd thаt tlrеrеWas no еvidеrrсеsupporting Еrnst Мayr's influеntiаl viеw of a ..gеnеtiсrеvolution'' that oссurs during spесiation, during whiсh a largе fraсtion of thе gеr-romесhangеs Ьесаusе of nеw sеlесtivе prеssurеsaftеr сolonizаtion. tVhitе also strongly favorеd intеrprеtаtions of symp:rtriсspесiation in many insесt groups, suсh as Rhagolеtis fruit fliеs' still studiеd today in this сontеxt. Сontrary to mally othеr authors of his timе (and ours), hе сritiсizеd ..еthologiсai spесiatiorrisrs''whсl strongiy аdvoсаtе sехual disсrimination and othеr Ьеhaviors as Ьеing of paramount importanсе to spесiation. Instеad,hе suggеstеdthat hyЬrid proЬlеms may Ье motе сommon еarly in spесiirtion.Although his viеw is not widеly aссеptеd toda,v' Сoynе zrnd Orr (2004) also notе thе ovеrеmphasisplaсеd Ьy somе authors on sехuаl disсrimination whеn thе rеlativе importanсе of еffесts from suсh disсrimination vеrsrrs hybrid proЬiеnrs iп spесiаrion has rrot Ьееrrdеfinitivе[ydеmоrrstгatеd. Whitе's tеxt is a riсhly dеtailеd rеviеw of thе litеraturе on spесiation.Thе disсussions of еnrpiriсal studiеs of spесiаtion arе tlrorough and еloquеnt. !Иhitе was an oцtstanding сytologist, Ьut likе mаrny Ьiologists, hе Ьесamе сonvinсеd that thе phеnomеna hе studiеd wеrе of paramount importanсе in spесiation.Although somе of his intеrprеtationsarе unpopular today, nO onе сan douЬt that this tехt Was inf]uеntial irl motivаting sеvеral outstаnding studiеsof spесiation.Somе of his сontrоvеrsial viеws may yеt Ье vindiсatеd; many сontinuе to Ье aсtivе arеas of study. This quotе from his tехt still appiiеs: ..And, at thе prеsеI1ttimе' it wсlцld sееm that swееpirrggеnеralizаtiоns aЬout mеthods of spесiation should Ье avoidеd as fаr as possiЬlе (it may Ье morе justifiaЬlеto gеnеra|lzetn 2О -Yеarstimе)'' (Whitе 1978, з24).

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BIBLloGRAPнY Сoynе, J. A.' аnd Н. A. Orr. 2004. Spесiаtioz. Sundеrlаnd,МA: Sinauеr Assoсiatеs. Dеlnеri, D., I. Сolson, S. Grammеnoudi, I. N. RoЬеrts, Е. J. Louis' and S. G. Olivеr. 200З. Еnginееring еvolutiсlnto study spесiationin yе:rsts.Nаtиrе 422: 68*72, Ortiz-Bаrriеntos' D.' J. Rеiland, J. H.y, and M. A. F. No
Nlonаd to NIап: The Сonсеpt of Progress in ЕuolutionсIrу Biologу (Miсhaеl Rusе) Еvolutiоnаry idеas Ьесamеpopul:rrin N7еstеrnсiviliz:ltionjust whеn сonсеprs of lruman progrеss wеrе flourishing. The Industrial Rеvolution and thе gгowth of sсiеnсе itsеlf lеd еduсetеd pеoplе to ехpесt limitlеss progrеss in human knowlеdge and in human soсiеty. Many сommеntatoгs havе suggеstеd that idеologiсal Ьеliеfs aЬout human progrеss Wеrе a motivаting faсtor in Ьеliсfs aЬout еvolution аnd еspесially in Ьеliеfs aЬout thе progrеssivеnеssof еvolrttion. Мiсlraеl Rusе sеt out tо irrvеstigatеwhеthеr pеrsоlrаl Ьеliеfs of sсiеntists aЬout progrеssivеnеss in human soсiеtyand in еvolutiсlnwеrе сorrеlatеd. Мonаd to Маn is thе rеsr"rltof this study. Rusе сonсludеs that sсiеntists' Ьеliеfs aЬout thе progrеssivеnеssof еvolution wеrе indееd сorrеlatеd with thеir ЬеliеfsaЬout soсial progrеss.This providеs a сhallеngеto thе oЬ1есtivity of thе sсiеntifiсЬеliеf in еvolutionary progrеss.Judgmеnts of progrеssivеnеss сannot Ье dеmonstratеdon str:rightforwardеmpiriсal grounds; thеy arе nor. mativе аssеssmеntsof what сoul1ts as ..forward'' сhirngе. Сould thе mеtа. phoriсal irrfеrеnсеfrtlm soсiаl progrеss to еv
Thе аltеrnаtivеtO trri Was to find a wаr,vttl s framеwork for suсh a st lution in thе 1930s and wеrе thеmsеlvеs prсlgrе t w е е n p r o g r е s s i o n i s nl frаnrеrvork foг nоrrpro partly Ьесausеthе Ьеliе Thе Ьook,s valuе is r с o m Ь i n е s a s w е е p i n gh i a Ь o u t i n d i v i d u a ls с i е n t also sеnsitizеrеadеrstс, в|BLloGRAPHY

1996.Мol Rusе' l\4iсhaе|. Biolсlgу.Cаmbгidgе,,

.lvlorgan,Thomas I

originаlly trainеd as irn thе prinсipal arсhitесtsс p е r i o d 1 9 1 0 - 1 9 3 . 5H. е r ology or Меdiсiпе (193j

dеmonstrating thаt Mеп rod-shapеd bodiеs founr еnormous influеnсе nсlt' in еmЬryology and еspе his group rеsolvеd thе qt work of Gгеgor Мепdе hypothеtiсаl сonstгuсts1 hеrеdity or rеprеsеntеd transmittеd as disсrеtеb p o r t а n t d е Ь а t еs i n с ес r i itеd valuе Ьесausеthе Ьl T. H. Мorgan wаs [r h е е n d o f t h е U . S .( . i v

h i s е s s а yo n h r Ь г i d i z . r t f a m i l y t h а t i n с l u d е dh i s gеnеral and lеadеr of } Sсott Kеy (1779_184З) thе Statе Univеrsity of rеrеd Johns Hopkins U Williаm Kеith Brtl
sis on thе еvolutionагy C r u s t а с е аa n d A r а с h n i сonсludеd that thе gгou

Мorgап

MA: SinauеrAssoсratеs. :ndеrlаnd, lЬеrts'Е. J. Louis,and S. G' olivеr. tionin yеаsts.Nаturе422: 68-72. A. F. Noоr. 2002.RесomЬination епеtiсd116,nos.2_3: |67_\78. .W. Frаnсisсo: H. Frееman. ^4.А.F.N.

rogress

Rusе) :rn сivilization just whеn сonсеpts ustriai Rеvolution and thе growth pесt limitlеss progrеss in human )mmеntators havе suggеstеd that /еrе a motivating {aсtor in Ьеliеfs )out thе progrеssivеnеssof еvolurеthеrpеrsonal Ьеliеfs of sсiеntists in еvolution wеrе сoгrеlatеd. y. Rusе сonсludеs that sсiеntists' гion wеrе indееd сorrеlatеd with vidеsa сhаllеngеto thе oЬjесtivity .еss. J u d g m е n t so I p r o g r е s s i v е n е s s J еmpiriсalgrоunds;thеy arе norrward'' сhаngе. Сould thе mеtal еvolutionary progrеss Ье takеn | е s t i O nR u s е a s k s t h r е е q u е s г i o n s ttеmporaryеvolutionists.First, do ;s сorrеspond to what onе Would еasaЬout soсial progrеss?Sесond, Ьеtwееnsoсial progrеss and bio1 thе Ьiologiсal viеws outstrip thе эnсеand thеory, thе morе likеly it gap Ьy his or hеr soсial Ьiasеs. nost all ninеtееnth-сеnturyеvolutionists Wеrе progrеssionists with }ut sесond,thеy sееm to havе rесnitionis rеvеalеdin diffеrеnсеsЬеopiсs and thеir nonеvolutionary lесturеsand popular writings, Ьut iсiеntifiсrеsеarсh.Thomas Hеnry as a pеrfесt ехamplе of this tеns on еvolutionЬut largеly сonfinеd nparativеmorphology.

Thе altеrnativеto trеating еvolution as a popular (Ьut not a rеsеarсh)topiс Was to find a way to study еvolution that did not assumе progrеssion. A fгamеwork for suсh a study finally appеared with thе synthеtiс thеory of еvolution in thе 1930s and 1940s, Ьut many of thе arсhitесts of that synthеsis Wеrе thеmsеlvеsprogrеssionists.only in rесеnt yеars has thе assoсiation Ьеtwееn progrеssionism and еvolutionism fadеd. This is partly Ьесausе thе framеwork for nonprogrеssionist еvolutionary studiеs has advanсеd, and partly bесausеthе Ьеiiеf in soсial progrеssionismhas fadеd. Thе book's valuе is not solеly in its сonсlusions about progrеssionism.It сomЬinеs a swееping history of thе sсiеnсеof evolution with intriсatе dеtails aЬout individual sсiеntists'rеsеarсhеs,prеjudiсеs,аnd pеrsonal livеs. It сan also sеnsitizеrеadеrsto suЬtlе progrеssionisttеndеnсiеsin thеir own thought. BlвLIoGRAPHY Rusе,Мiсhaе|. |996. Мoпаd to Мап: Тhе Сoпсеptсlf Progrеssiп Еuolиtioпаrу -R.А. Biologу.СamЬridgе,МA: HаrvardUnivеrsityPrеss.

Мorgan, Thomas Hunt (|866_1945) originally trainеd as an еmЬryologist, Thomаs Hunt Мorgan Ьесamе onе of thе prinсipal arсhitесts of thе Mеndеlian сhromosomе thеory of hеrеdity in thе pеriod 1910_1935. Hе was thе first gеnеtiсist to Win thе NoЬеl Prizе in Physiology or Mеdiсinе (1933) for thе work hе and his laЬoratory group сarriеd out dеmonstrating that Mеndеlian gеnеs wеrе physiсal parts of сhromosomеs' thе rod-shapеd Ьodiеs found in thе nuсlеus of all еukaryotiс сеlls. This work had еnormous influеnсе not only in thе rapidly dеvеloping fiеld of gеnеtiсsЬut also in еmЬryology and еspесially еvolutionary Ьiology. Thе work of Morgan and his group rеsolvеd thе quеstion whеthеr thе hеrеditary faсtors postulatеd in thе work of Grеgor Меndеl (1822_1884) in thе ninеtееnth сеntury wеrе mеrеly hypothеtiсal сonstruсts that wеrе сonvеniеnt for ехplaining сеrtain pattеrns of hеrеdity or rеprеsеntеdrеal, matеriаl сomponеnts of thе organism that wеrе transmittеd as disсrеtе Ьodiеs from parеnt to offspring. This was not аn unimportant dеЬatе sinсе сritiсs оf thе nеw gеnеtiсs maintainеd that it was of limitеd valuе Ьесausеthе Ьаsiс units, gеnеs,had no physiсal rеаlity. T. H. Мorgan Was Ьoгn in Lехingtоn, Kеntuсky, tn 1866, onе yеar after thе еnd of thе U.S. Сivil \й/arand thе samе yеar in whiсh Меndеl puЬlishеd his еssаy on hyЬгidization in pеas (Pisum). Мorgan сamе from a distinguishеd family that inсludеd his unсlе.}ohnHunt Мorgаn (182-5-1864)'Сonfеdеratе .War, and Franсis gеnеral and lеadеr of Morgan's Rаidеrs during thе Сivil ..Thе Star-SpanglеdBаnnеr.'' Еduсatеd at Sсott Kеy (1779_1s4З), author of thе Statе Univеrsity of Kеntuсky (now thе Univеrsity of Kеntuсky), hе еntеrеd Johns Hоpkins Univеrsity in 1886 as a studеnt of morphology undеr .s7illiam Kеith Brooks (1848_1908).Не rесеivеdhis PhD in 1891 with a thеsis on thе еvolutionary rеlationship of thе sеa spidеrs (Pyсnogonida) to thе Сrustaсеa and Araсhnidа. From a dеtailеd anаlysis of еarly еmЬryology hе сonсludеd that thе group was most сlсlsеlyrеlatеd to thе Araсhnida, Ьut that

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Мrlrgап thе two groups must havе divеrgеd from a сommon anсеstor in thе distаnt p a s t . A f t е r a s ш m m е r( 1 8 9 1 ) а r r dt h е r rа y е a г ( 1 8 9 4 _ 1 8 9 5 )a t t l r е N a p l е s m a rinе laЬoratory (Stazione Zoologiса) working сlosеly with thе еmЬryologist Hans DriеsсЬ'(1'867-1'941), Morgan gavе up thе largеly dеsсriptivеand spесulativе sсiеl-lсеof morphology and Ьесamе ir сomrтittеd ехpеrimеntalist.Еxpеrimеntation, hе сamе tсl bеliеvе,pгovidеd a morе rigorous and analytiсal way to approaсh biologiсаl rеsеarсh than thе spесlrlativе and untestaЬlе phylogеnеtiс hypоthеsеs of thе morphologists. Morеovеr, thе quеstions ехpеrimеntаlists suсh as Driеsсh wеrе asking сonсеrnеd important Ьiоlogiсal proсеssеsoссurring in thе prеsеnt (for ехаmplе, thе mесhanisrrrof еmЬryoniс diffеrеntiation)rathеr than historiса1(phylogеnеtiс)rеlationships.Не сollaЬoratеd with Driеsсh on a sеriеs of еХpеrimеnts On thе dеvеlopmеnt of сtеnophorеs (popularly сallеd сomЬ iеlliеs)' шarinе invеrtеЬratеsthat havе а supеrfiсial rеsеmЬlаnсеto jеllyfish. Тhе ехсitеmеnt of Ьеing aЬlе to analyzе сomplех physiologiсal or dеvеlopmеntal proсеssеsdiгесtly Ьy manipulating thе organism or its еrlvironmеntсonvinсеd Morgarr this wаs thе dirесtion in whiсh modеrn Ьiolсlgy nееdеd to proсееd. N4organhеld thгее tеaсhing positions during his сarееr:at Bryn Mawr Сollеgе (1891_1904), СolumЬia Univеrsity \\904-1928), and thе Саlifornia Institutеof Tесhnologу 092.8-1945), whеrе hе foundеd thе Division of Biologv. Throtrglrout all thеsе yеars hе spеnt suшп1еrsat thе Мarinе Biologiсаl LaЬoratory in \й/oсldsНolе, Мassaсhusеtts, whiсh hе and othеr Ьiologists сonsidеrеd thе Amегiсan Nаplеs. During his Bryn Mawr pеriod Мorgan workеd mostly on proЬlеrтs of ехpеrimеntal еmЬгyology, using organisms suсh as frogs, еarthworms, аnd sеa urсhins. lt was only аftеr arriving at Сolumbia Univеrsity' starting аround |907, that hе Ьесamе faпriliаr with thе fruit fly, Drosophilа mеlапogаstеr. Thе work for whiсh hе and his laЬoratory group at СolumЬiа suЬsеquеntly (aftеr 1910) Ьесamе most famous, еstaЬlishing thе Меndеlian сhromosomе thеory of hеrеdity,was initiаtеd and сarriеd out during thе СolumЬia yеars (sееfigtrге).Although hе transportеdhis ..fly laЬ'' to Pаsadеna in 1'928,his administrativеdutiеs took him away from dаy-tо-dаy fly rvork, аnd Whеn hе did rеtllгn tо thе lаЬoratory' proЬlеms of еmЬryoniс dеvеlopmеnt rеsuгfасеdаs his mаin intеrеst. Two mаjor aspесts of Мorgan's Work rеlаtе to thе dеvеlоpmеnt of еvoluhis еarly opposition to tiorrary thесlry in tlrе twеntiеth сеnttrry.Thе first r,vаrs Darwin's thеory of natural sеlесtion (1903_1915) as a mесhanism for how еvolution, еspесially аdaptation, сould oссur. Thе sесond wаs his skеptiсism aЬout Ьoth thе Mеndеlian and сhromosomе thеoriеs of hеrеdity. Morgan's initial сlЬjесtionsto Darwin's mесhanism оf natural sеlесtion wеrе voiсеd in his Ьook Еutllцtiсlп апd Аdаptаtiсlп (|903\' irr whiсh hе arguеd that sеlесtion сould nеvеr produсе wholl1' nеw spесiеsЬy aсting on slight individual diffеrеnсеs (rеfеrrеd to at thе timе as сontinuous or fluсtuating variations), as Darwin had сlaimеd. Bесausе suсh variatiс-lnsWеrе sп-rall,еvеn if thеy сon..swampеd fеrrеd somе advant;.rgе,thеy would tеnd to gеt out'' in suссеssivе gеnегations. In additiсln, Mоrgan arguеd thаt fluсtuating vari:rtions oссurrеd асting on suсh vаriаtions, сould only rarеly and Ь1' сhanсе, so that sеlесti
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Тhomаs Hunt Мorgan and аnd Саlvin B. Bridgеs)rnаp somеs of Drosophilа. TЬis i Мепdеliап Herеditу (1915)

Мorgаn :ommon allсеstor in thе distant (1894-1895)at thе Naplеs mag сlosеlywith thе еmЬryologist thе laгgеlуdеsсriptivеand spессommittеdеxpеrimеntalist.Еxa morе rigiоrousаnd analytiсal and untеstаblе thе spесr"rlativе г s . М o r е o v с г ' г h е q r r е s t i o n sе х сonсеrnеdimportant Ьiologiсal llе' thе mесhanisnrof еmЬryoniс rеlаtionships.Hе сollab1еnеtiс) imеnts on thе dеvеlopmеnt of marinе invеrtеЬratеsthat hаvе a tеmеnt of Ьеing aЬlе to ana|yze )сеssеsdirесtly Ьy manipulating И o г g a nt h i s w a s r h е d i г е с t i o n i n ng his сarееr:at Bryn Mawr Сol904-1928\' and thе Сaliforniа hе foundеdthе Division of Biol_ Lmmеrsat thе Marinе Biologiсal , whiсh hе and othеr Ьiologists his Bryn Мawr pегiod N4organ а l е m Ь r y o l o g y .u s i n g o r g a n i s m s It was only aftеr aгriving at Сo. lrаt lrе Ьесаmе familiar with thе
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Тhomas Hunt Мorgan and his young assoсiatеs(A. F{. Sturtеvant'H. .I.Мullеr, and Сalvin B. Bridgеs)mаppеd thе оrdег of gеnеson thе fouг (pairsof) сhromоsomеsof Drosophilа. This is thе frontispiесеof thеir Ьook, Thе Мeсhапism of Мeпdeliаn tlerеditу (19 15).

747

748

Мorgап lrеvеr pг()duсеthе finе-trrnесladaptations sееn thror'rghoutthе living world. Bе. twееn 1903 аnd 1910 Morgаn advoсatеdHugo dе Vriеs's (1848-1935) mutation thеory, whiсh сlаimеd thаt nеw spесiеsаrosе in onе stеp Ьy lаrgе-sсalе mutations that ссluld makе an offspring a diffеrеnt spесiеs from its pаrеnts. This thеory, for whiсh thеrе appеarеd to Ье sound еxpеrimеntal еvidеnсе in dе Vriеs's nlodеl organism, thе еvеning primrosе (Оепothеrа lаmаrchiапа), wzts еspесiаlly :rppеаling to Morgаn аnd nrany of his сontеrnporzrriеsnot only Ьесаtlsе it сirсumvеntеd thе oЬjесtions to Darlvirriаn thеory outlinеd еarliеr, lrut also Ьесausе it wаs сlaimеd to Ье an eхpеrimепtаl aуlproaсh to еvolutiсrп.Dе Vriеs wirs aЬlе to hyЬridizе diffеrеnt variеtiеs and spесiеs of oепotherа zlnd produсе thе supposеdly nеw, mutatеd spесiеs at will. Although dе Vriеs's mutаtion thеory was latеr abandсlnеdЬесausеit was found to Ье thе rеsult of :r variеty of сhromosomal anomilliеs pесuliar to Оeпсlthеrа (and thus did not produсе nеw spесiеs),it sегvеdfor гnany at thе timе, likе Мorgan, as а viaЬlе аltегnаtivеtо Dаrwinian nirtuгalsеlесtion. Dr'lгing thе samе pеriod (190з-1 910) Мorgan was also skеptiсal оf thе Меndеlian thеory as an ехplanation of thе rеsults of hyЬridization and thе сhromosomе thеory as an еxplanation of suсh phеnomеna as sех dеtеrmination. To Мorgan thе Mеndеlian thеory, likе numеrous othеr partiсulatе thеoriеs of hеrеdity in thе latе ninеtееnth сеntury (rlrosеof Darwin, Еrnst Нaесkеl, August !7еismann' or Сilrl Nigеli' to namе а tЪrv),was сouсhеd in tеrms of hypothеtiсal ..faсtоrs'' or pаrtiсlеs аnd w:rs thеrеforе сomplеtеlу spесtrlativе.Asidе from tlrе faсt that thе ехistеnсеof thеsе supposеd f:rсtors сould not Ье сonfirmеd, Morgan's oЬjесtionsto Mепdеlian thеory wеrе thrееfold. First, if, аs Меndеlians sееmеdto сlaim, sеx Wi1sa hеrеditary trait, tl.rе Меndеlian thеory сould not aссount for thе 1:1 sех ratio found in most animals (and plants). Sесond, Morgan thought that Меrrdеlians trеаtеd phеn
homologous сhromosomе thе signifiсanсеof thе сhrt ogist Morgan had a strong oriеs bесаusе thеy sееm prеformation, whiсh hаd с w a s m е r е | yг h е u n f i l l d i l r g.

Rеfеrгing сomplех аnсl с]l сlеs in thе gеrm сеlls, Мtl planatory Ьut in faсt ultirт Ironiсally Мorgan Ьеgа thе spring of 1910 and tl from his own studiеsсlf D; in his СolumЬia lаЬorzrro г i o n s с r fd е V r i е s i e nt y p е i l l сlЬsеrvеd among his сultu еyеs. It wаs a malе, and hе red-еyеd. But whеn Ье Ьr ratio of roughly onе whit Ьasiсally thе ехpесtеd Mе еrozygous foг а гесеssir'сt rеd, whiсh Was d()n1ll12 n < l r е dr h а r а l l t Ь е w h i t с - е е y е _ с o l o ri n h е r i t a n с е( 1 9 1 must somеhow sеgrеgiltеv mеtеs.Bur this ехplап.rt apparеnt Ьiologiсal Ьasisf. soon сamе tO sее' thе firсt s o r y с h r o m o s o m е s( i n p а r solnеs' еvеn if onе of tlrеrr п.raskеdЬy thе rеd fасtor t еvеr, in malеs, with сlnly ol п.raskеdаnd thus woulсl sh gan Was сonvinсеd thаt N Ьаsis if it wеrе assumесl1 l 9 0 9 l a Ь е l е d8 . с , 7 с s( ). ( . с t

mosomе. S u Ь s е q u е n t l yt h е i d е a r somе was givеn fuгthеr sr ( 1 8 6 1 - | 9 2 6 ) a n d o t h е г sh morе trаits togеthеr. Alth nomеnon in tеrms сlf thе с his studеnts,did. Indеесl,I mapping а gеnе's aсtr-rzrllv gan notеd, linkagеs appеa thе two homologous сЬro llаd асtually ехсhangссlpа

Мorgап throughoutthе living world. Bе;odе Vriеs's (1848-1935) mutaaгosеin ()nе stеp by largе-sсalе Еfеrеntspесiеs from its parеnts. und ехpеrimеntalеvidеnсе in dе : (Оепothеrа lаmаrсkiапа), was his сontеmporaгiеsnot only Ьеnian thеory outlinеd еarliеr, Ьut епtаl approaсh to еvolution. Dе ; and spесiеsof Оeпotbеrа and at will. Although dе Vriеs's mu_ was found to bе thе rеsult of a o Оепothеrа (and thus did not lr timе' likе Morgan' as a viaЬlе )rgan Was also skеptiсal of thе rеsultsof hyЬridization аnd thе h p h е n o m е n aа s s е х d е t е г m i n а kе numеrous othеr partiсulatе еntury (thosе of Darwin, Еrnst to namе a fеw), was сouсhеd in ; and was thеrеforе сomplеtеly stеnсеof thеsе supposеd faсtors to Mеndеlian thеоry Wеrе thrее1' sех Was a hеrеditаry trait, thе l : l s е х r а t i of o u n d i n m o s t a n i that Mеndеlians trеatеd phеnodisсrеtе,sharply diffеrеntiatеd :,animal сoat сolor) rangеd ovеr M е n d е l i a n ss е е m е dt o i n v е n t a s ,lain any givеn hеrеditary сondil d n o t s u f f i с еr о е x p l a i n a p а r r i с еd (asin сasеsof еpistasis'whеrе anothеr).Не also quеstionеd thе lеparation of thе two faсtors for at еaсh еndеd up in a diffеrеnt until 1910 Morgan сlaimеd that ad anythingto do with hеrеdity' W i l s o n ( 1 s 5 6 _ 1 9 з 8 )a n d f o г m е r : thе so-сallеdaссеssoryсhromolrе rеsponsiЬlеfor dеtеrmination ;hсhromosomеsWеrе сlеarly visdеsсriptivе work had Ьееn donе hе proсеss of distriЬuting thе : i o s i s ( t h е p г o с е s sо f s е p a r a t i n g

homologous сhromosomеs duгing rеduсtion division in gamеtе formation), thе signifiсanсеof thе сhromosomеs was still unсlеar. Finally, as an еmЬryologist Мorgаn hаd a strong аvеrsion to both Mеndеlian and сhromosomе thеoriеs Ьесausе thеy sееmеd likе rеvеrsions to thе long-rеjесtеd thеory оf prеformation,whiсh had сlaimеd that thе proсеss of еmЬryoniс dеvеlopmеnt was mеrеly thе unfolding of miniaturе еmЬryoniс parts into adult сharaсtеrs. Rеfеrring сornplеx and dynamiс Ьiologiсal proсеssеsЬaсk to invisiЬlе partiсlеs in thе gеrm сеlls, Мorgan сlaimеd, might sееm at first glanсе to Ье еxplanatory Ьut in faсt ultimatеly ехplainеd nothing. Irсlniсally Morgan Ьеgan to сhangе his rтind on all thrее thеoriеs Ьеtwееn thе spring of \9|О and thе wintеr of 1'911. Thе major impеtus сamе first from his own studiеsof Drosophila. Мorgan had Ьеgun Ьгееdingthе fruit fly in his СolumЬia laЬorаtory around 1908 to sее if hе сould produсе mutations of dе Vriеsian typе in animals. Hе had gottеn nowhеrе whеn onе day hе oЬsеrvеd among his сulturеs of normally rеd-еyеd fliеs onе that had whitе еyеs.It was a malе, and hе Ьrеd it to a rеd-еyеdfеmalе;thе offspring wеrе all rеd.еyеd. But whеn hе Ьrеd thеsе offspring with еaсh othеr, hе oЬtainеd a ratio of roughly onе whitе-еyеd fly for еvеry thrее rеd-еyеd fliеs. This was basiсally thе ехpесtеd Меndеlian ratio for a сfoss Ьеtwееn two parеnts hеtеrozygous for a rесеssivеtrait (in this сasе whitе wаs said to Ье reсеssivеto rеd, whiсh was dominant to Whitе). Morе important, howеvеr, Моrgan notеd that аll thе whitе-еyеdf]iеswеrе malеs. In his first puЬlishеd papеr on еyе-сolor inhеritаnсе (1910), Моrgаn assumеd that thе faсtor for whitе еyе must somеhow sеgrеgatеwith thе faсtor for malеnеssin thе formation of gamеtеs. But this ехplanation Was not wholly satisfaсtory sinсе thеrе Was no apparеntЬiologiсal Ьasis for assuming suсh sеlесtivеsеgrеgationunlеss,as hе soon сamе to sее' thе faсtors for dеtеrmining еyе сolor rеsidеd on thе aссеssory сhromosomеs (in partiсular thе Х). Sinсе fеmalеs had two Х сhromosomеs' еvеn if onе of thеm had thе nеw mutant faсtor fсlr whitе, it would Ье maskеd Ьy thе rеd faсtor on thе homologous' or pаrtnеr сhromosomе. F{owеvеr,in malеs, with only onе Х сhromosomе' thе mutant faсtor would not Ье m a s k е da n d t h u s w o u l d s h o w u p a s t h е w h i t е - е y е dp h е n o t y p е . B y 1 9 1 1 M o r . gan Wаs сonvinсеd that Mеndеl's thеory сould Ье givеn a сonсrеtе matеrial Ьasis if it wеrе assumеd that faсtors, or what !Иilhеlrn Johannsеn had in 1909 laЬеlеd8епеs' oсclpiеd a spесifiсphysiсal rеgion, or loсus, of thе сhro. mosomе. Subsеquеntly thе idеa of gеnеs as arrаngеd linеarly along thе сhromosomе wаs givеn furthеr support Ьy oЬsеrvations On what \Х/illiam Batеson (\86|-1926) and оthеrs had idеntifiеd as linkagе, thе inhеritаnсе of two or morе traits togеthеr. Although Batеson himsеlf did not intеrprеt this phеnomеnon in tеrms оf thе сhromosomе thеory, othеrs, inсluding Мorgan and his studеnts,did. Indееd,Morgan usеd thе idеa of linkagе to dеvisе a way of aсtually mapping a gеnе'sptlsitiсlnon thе сhromosomе. on oссasion, Morgan notеd, linkagеs appеarеd tсl Ье Ьrokеn and thе gеnеs rесomЬinеd, as if thе two homologous сhromоsomеs on whiсh a group of gеnеs wеrе lсlсatеd had aсtually ехсhangеdparts:

749

7.'0

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offspring сhromosomеs аB Morgan supptlrtеdthis idеa from work Ьy a Bеlgian сyt()l()gist'F. A. Janssеns (186З-1924), who had dеsсriЬеd in a 1909 pаpеr what hе сa||edchiаsmаtуpie, or thе intеrtwining of thе two homologous mеmЬеrs of а сhromosomе pair during mеiosis, and what appеarеdtо Ье thеir suЬsеquеntЬrеaking and rеjoining. Мorgan аnd his studеnt A. H. Sturtеvant (1897_\97\| reasonеd that thе frеquеnсy with whiсh rесomЬinatiсln сould Ье oЬsеrvеd in offspring was a funсtion of thе distanсе apart сlf any two gеnеs on thе сhromosomе' and this providеd a way to еstimаtеat lеast thе rеlаtivеpositions of gеnеs with rеspесt to еaсh othеr on thе samе сhromosomе. This mapping proсеdurе soon Ьесamе for Morgan and his laЬoratory group-inсluding, in a d d i t i o n t o S t u r t е v a n t ,С a l v i n B . B r i d g е s ( 1 8 8 9 _ 1 9 З 8 ) a n d H . J . M u l l е r (1890*1967)-thе Ьasis of an еlaЬoratеrеsеarсhpro!]ramthat was ехtеndеd by othеr workеrs to hundrеds of organisms (сorn, thе mousе, and thе rat) ovеr thе nеХt з0 yеars. It was for еstaЬlishingthе validity of thе сhrсlmosomе thеory of hеrеdity that Мorgan was awaгdеd thе NoЬеl Prizе in 1933. Мorgan's own turnaЬout with rеgard to gеnеtiсsand thе сhromosomе thеory lеd him to sее that Mеndеliаn variations-thе diffеrеnсеЬеtwееnrеd and whitе еyеs or Ьеtwееn wild-typе and Ьеadеd wings-might Ье ехaсtly thе sorts of variаtions on whiсh natural sеlесtionсould aсt. Iл|916, for a sеriеs of lесturеsat Prinсеton (puЬlishеdas A Сritiquе of thе Thеorу of Еuоlutioп), Мorgan notеd that thе many variations hе had oЬsеrvеd tл Drosсlphilа werе .Whеrеas disсrеtе,staЬlе,and inhеritеd. еаrliеr hе hаd arguеd that small individuаl or fluсtuating variations would always tеnd to Ье swampеd, thе disсrеtеМеndеlian variаtionswould not. Thеsе сould Ье aссumulatеdindеfinitеly аnd thus сould lеad еvеntually to thе formation of a nеw spесiеs.In his lаtеr writings on еvolution (1925 and 19З2) he arтplifiеd thеsе viеws, сlеarly hаving сomе to aссеpt thе Ьasiс outlinеs of Darwin's thесlry. It was for othегs, howеvеr' with morе mathеmatiсal lеanings to usе thе nеw gеllеtiсsto formuiatе thе maturе form of Darwinian thесlrvthаt саmе to Ье known as thе еvolutionary synthеsrs. B|вLIoGRAPнY Allеn, G. 1968'ThomasHunt Мorgаn аnd thе proЬlеrnof nаturаlsеlссtiсln. Jourпаl of thе Historу of Bkllogу 1: 11З_1З9. 1'978.ТhсlmаsНuпt Мсlrgап:Thс Мап апtl His Sсiепсе,l)rinсеton, NJ: PrinсеtonUnivеrsityl)rеss. 1980.Тhе еvolutionarysynthеsis: Моrgirrraпd nirtuгalsеlесtionrеvisitсd. In Е. Mayr and !И. Pгovit.tе, еds',Thе ЕuolutioпаrуS),пthеsis: Pеrspcсtit,еs oп thе Uпifiсаtitlпof Biologу,356_.]82. СanrЬriс1gе, MA: HarvаrdUnivеrsityPrеss.

N4aiеnsсhеin,J. 1991. Thol iп Amеriсаn Bfu'l,'g1, N4organ' T. H. |90З. Еuсll 1910. Sех liпritеdi 1916. A Сritiqиe о Univеrsity Prеss. A4orgаn, T. H., А. H. Sturt Месhаnism of Мепdеl, Shinе, I.' and S. \й/roЬеl.19 Lехington: Univеrsity .

lV1ullеr,Hеrmann Jt

.W.hеn H. J. Мullеr was с ехhiЬit on evolution at mеmЬеrеd Ьеing imprеs sizе and anatomy сhang known as а gеnеtiсist ar thаt Х-rаys induсе gеnе his profеssional and pеrs a t t е n d е dС o l u m Ь i a U n i v two grеat Amеriсan Ьiol .!7ilson Мorgan. was a с gеnеration of Ьiologists volvеd in hеrеdity, dеvе еvеntually provеd lil/ilso mеlаnogаstеr. In his sеnr foundеd a Ьiology сluЬ Bridgеs еnjoyеd sharing' that was сгеatingsuсh а s t h е k е y f i g u r е si n p u t t i n fruit fliеs univеrsally kno Mullеr rесеivеd his Pl whеn N4organ and Sturt him to a study of what h 10 yеars to puЬlish thеs еxtеndеd ovеr many gеn of how Darwinian naturа g е n е st h а t с o u I dе i t h е ri n organ systеm or trait. N v a r i a Ь l е ,а n d h е i s o l a t е d ations. Мullеr, likе Darr аnd that nеw organ systе N4ullеr workеd first at of Tеxas in Austin. !7hili mutation and thе gеnе. l individuаl gеnе and argt

Мullеr гomos()mе :hгOmosоmс

Bеlgianсyt()logistlЕ. A. Jarrssеns )9 papеr whirt hе сa||cd cbiаslologсlusmеmЬеrs of a сhromoЬrеaking l to Ье tlrеirstrЬsеqr"rеnt ( 1 8 9 1 _ 7 9 7 1 )r е a H. Sturtеvant rlЬinаtiсlnсould Ье oЬsегvеd irr rt of an,vtW()Е]еnеsсln thе сhroе аt lеastthе rеlativеpositiorrsof m с с h г o l n o s r l m еT. h i s m a p p i n g . laЬoratorygroup-inсluding, in ( 1 8 8 9 _ 1 9 з 8 )a n d H . J . М u l l е r :arсhprogram thаt was ехtеndеd s (сorn, thе lnousе, arrd thе rat) g thе validitу of thе сhromos()mе d t h е N o Ь е l P r i z еi n 1 9 3 3 . ;еnеtiсsаnd tlrе сhromosomе tlrе. i-thе dif{еrеnсеЬеtwееn rеd and Lеd wings-lnight Ье ехaсtl,v thе ln сould асt. In 19|6, for a sеriеs iqиe o| thе Thеorу of Еuсllution\, had oЬsегr,есlin Drosсlphilа were iеr hе hаd arguеd thirt smаll indirys tеnс{to Ье swilmpеd, tlrе disсouid Ье aссrrmulatеdindеfinitеlу Ltionof a nеr'vspесiеs.In his latеr rmplifiеdtЬеsеviеrvs,сlеarly lrаvarwin's thесlrv.It was for othеrs, to usе thе nеw gеllеtiсsto fсlгпruhat сarnеto Ье knоwn as thе еvo_

proЬlеmof nаtural st.lесtitlп. .|ottпlаl NJ: аnd Нis Sсiеltсt,.Prillс:еtсlr-r, lаn and nlltural sеlссtiоn геvisitсd.In Pеrspесtit'еsoп thе паrу 51,пthesis: lе' N,IA:Hаrvaгсl Univеrsit1.Prеss.

Мaiеrrsсhеin, J ' 199 1. Thomas Hunt Моrgаn. Сhaptеr 8 of Trапsformiпg Trаditioпs iп Аmеricап Biologl, 1890_1L)1.'.Bаltimorе:Johns Hopkins Univеrsity Prеss. lvlorgаn, T. H. l90З. Еuсllиtitlп апd Аdаptаtiсlи. Nеw Yсlrk; N1асmillаn. 191().Sех linritеd inhеritanсеiл Drosсlphilа.Sсiепсе З2: \2О-122. 1916. А Сritiquе сlf thе Thulrу o|-Еuсllutiсltt.Prinсеtot-t,NJ: Ргinсеtоn Univеrsity Prеss. Моrgan, Т. H.' A. H. sturtеvаnt,Н. .|.N,lullеr,аnd С. B. Bridgеs. t9 | 5. TЬе Месhапism of Мепdеliап Hеrеditу. Nеw York: Holt. Shinе' I., ar-rdS. !(гсlЬеI. 1977. Тhсlmаs Huпt Мсlrgап, Рiсlпееr сlf Gепеtiсs, [,ехingt()n:Univеrsity оf Kеntuсkу Pгеss. -C.Е,.А.

Мullеr, HеrmannJosеph(|s90-1967) !Иhеn H. J. Мullеr was aЬout l0 yеars o[d, hе wеnt with his fathег tO sее аn ехhiЬit on еvolution at thе Amеriсan Мusеum of Natural History. Hе rеrnеmbеrеd Ьеing imprеssеd Ьy thе small sizе of fossil horsеs аnd how thеir sizе and аnatomy сhangеd ovег rnillions of yеars. Although Nlullег is Ьеst known as a gеnеtiсistand won his NoЬеl Prizе (in |946) for work proving thаt Х_rays induсе gеnе mutations, lrе сonsidегеd himsеlf an еvolurionisсin his profеssiсlnaland pеrsoIrallifе. Мullеr was third-gеnеrаtionAmеriсan and attеndеd СolumЬia Univеrsity сln а sсholarship. Thеrе hе tсlok сoursеs with two Е]геatAmеriсаn Ьiologists' Еdmurrd Bеeсhеr wilson and Thomаs Hunt .sИilson Morgan. was a сytologist whosе writings hеlpеd сonvinсе a youngеr gеnеrаtion of Ьiologists who t
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Мullеr сomponеnts of thе сеll and thе organisnr wеrе produсts of gеnеs, as shown Ьy thе aЬnormalitiеs produсеd in thеm whеn thе normal gеnеs Wеrе altеrеd Ьy mutation. Mullеr also mеasurеd thе first spontanеous mutarion ratеs at a timе whеn thеy wеrе so rаrе that hе said that finding a nеw mutation was likе finding a dollar Ьill on thе strееt.Bу 1926 Mullеr had workеd out thе tools for mеasuring mutation ratеs Ьy dеsigning fruit.fly stoсks in whiсh hе сould dеtесt a сlass сallеd rесеssivеlеthals. If оnе of thеsе wеrе induсеd on a normal Х сhromosomе in a spеrm' thе resulting daughtеr ссluld Ье Ьrеd, and among hеr sons onе сatеgory of hеr two Х сhromosomеs in hеr immaturе rеproduсtivе сеlls would prоduсе fеrtilizаtions that killеd half hеr sons. Thе othеr half of hеr sons would bе killеd Ьy thе сhromosomе Мullеr dеsignеd. This сhromosomе' сallеd СlB (сontaining a supprеssor of сrOssing ovеr, С1 a lеthal, l; and a visiЬlе dominant еyе shapе сallеd Bar еyеs, B) allowеd Mullеr to ехаminе thсlusandsof vials of сontrol and Х-rayеd dеsсеndantsfor vials сontаining only daughtеrs and no sons. Не found thеsе in aЬundanсе with thе doses hе usеd (aЬout 4,000 roеntgеns).Thosе dosеs arе 10 timеs grеatеrthan thе dosе that would kill half of all humans еxposеd to it. It is not that fruit fliеs arе hardiеr than humans. Мany yеars latеr Mullеr showеd that Х-rays Ьrеak сhromosomеs, as wеll as induсе gеnе mutаtions. Brokеn сhromosomеs in dividing сеlls lеad to сеll dеath or' if thеsе сеlls arе spеrm' to aЬortеd еmЬryos. IndеpеndеntlyBarЬaгa МсСlintoсk showеd thе samе сyсlе of Ьrеaking lеading to сеll aЬnormаlitiеs in сorn (maizе) аnd сallеd this thе Ьrеakage-fusion-Ьridgесyсlе. Мullеr immеdiatеly rесognizеd that this сyсlе in fтuit fliеs and maize must Ье thе Ьasis of radiation siсknеss, еspесially whеn thаt oссurrеd among tеns сlf thousands of atсlmiс-ЬomЬviсtims in Hiroshima and Nagasaki. Мullеr rесеivеd his NoЬеl Prizе at a timе whеn thе аtomiс agе Was Ьеing ushеrеd in, аnd hе quiсkly Ьесamе an advoсatе fоr radiation protесtion in industry, mеdiсinе, and thе military appliсations of аtomiс Wеapons. N4ullеr madе many сontriЬutions to thе study of еvoiutiоn. Не was thе first to proposе an intеrprеtation of why po|yploidy (having thrее or morе sеtsof сhromosomеs instеad оf two) is rarе in аnimals and сommon in plants. In animals sех is usually dеtеrminеd Ьy sех сhromosсlmеs,whiсh arе rarе in plants. This makеs it impossiЬlе for triploid аnimals to produсе fеrtilе malеs. Hе dеmonstratеd that thе Y сhrornosomе (not normally found in fеmalеs) gradually losеs its gеnеs and shrinks in sizе (ovеr millions of yеars of еvolution). Mullеr also anаlyzеd hyЬrids of thе rеlаtеd spесiеs D. melапogаster and D. simulапs and suссееdеd in gеtting onе of thе tiny fourth сhromo. somеs of simulапs into an othеrwisе a|\-mеlапogаsterflу..lй/hat impairеd thеsе fliеs Was not somе vaguе physiologiсal inсompаtiЬility Ьut spесifiсgеnе diffеrеnсеs Ьеtwееn thе two that hе was aЬlе to idеntify. In thе 1950s Мullеr turnеd his attеntion to human еvolution and workеd out еquations to follow thе fatе of gеnе mutations in a populatiсln. Hе еstimatеd that in thе aЬsеnсеof nаtural sеlесtionthе load of mцtаtions prеsеnt in a population would douЬlе in aЬout four сеnturiеs.Hе also еstimatеdthat this douЬling of thе load сlf mutations Was thе еquivalеnt of suЬjесtinghu-

mans to a radiatiоn dсlsе tually soсiеty would havе to rеduсе this mutationa amount of timе аnd сost в|BLIoGRAPHY

Сarlson,Е. А. 1'98З.Gепе Мullеr.Ithaсa,NY: Со Mullеr' H. J. 1968.Studrc Blоomington:Indiana] his papеrs,and this Ьсl

МuIIеr ]еproduсtsof gеnеs,as shown Ьy hе normаl gеnеs wеrе alterеd Ьy pol-ttanе()us mutation rаtеs at a г findingа nеW mutation was likе Иullеr lrаd workеd out thе tools :ruit-flystoсks in whiсh hе сould of thеsеwеrе induсеd сln a norng daughtегсould Ье Ьrеd, and hromсlsonrеsirr hеr immаturе rе:ls that killеd hаlf hеr sons. Thе tе сhrоmosomеМullеr dеsignеd. l supprеssorof сrossing ovеr, с; apе саllеd Bar еyеs, B) allowеd 'trol and Х-rayеd dеsсеndantsfor rs. Hе fсlund thеsе in aЬundanсе :gеns).Тlrosе dosеs аrе 10 tirnеs all hшпrаnsехposеdto it. It is not 1y yеars latеr Mullеr showеd that tсе gеnеmutations. Brokеn сhro. .h or, if thеsе сеlls arе spеrm' to [сСlintoсkshowеd thе samе сyсlе L сorn (mt-rizе) аnd сallеd this thе diatеlу'rессlgnizеdthat this сyсlе of radiаtion siсknеss, еspесially ds of atсlmiс-ЬomЬviсtims irr Hi_ ; NoЬеl Prize at a timе whеn thе quiсkly Ьесamе an advoсаtе for and thе military appliсations of :ud,vof еvolцtion.Не wаlsthе first эidy (havingthrее or morе sеts of rimals :rnd сommon in plants. In с h г o m o s o m е sw , hiсh arе гаrе in l аnimalsto produсе fеrtilе mirlеs. (not normally found in fеmalеs) l (ovеrnrillions of yеars of еvolurеlatеd spесiеsD' melапogаstеr onе of thе tiny fourth сhromoпelапсlgаsterfly. What impairеd I inсompatiЬilityЬut spесifiс gеnе lе to idеntify. to human еvоlution and wсlrkеd пt:rtionsin а populatiсln. Не еstiion thе loаd of mutations prеsеnt .сеntttriеs. Hе аlso еstimatеdthat ; thе еquivalеntof suЬjесting hu-

mans to a radiаtion dosе of aЬout 150 roеntgеns.Mullеr sugg,еstеd that еvеn. tually soсiеty would havе to prасtiсе somе foгm of voluntаry sеlесtivеЬrееding to rеduсе this rrrr'rtational load' or humanity would suffеr а disproportion.rtе amount of timе and сost to patсh up its infirmitiеs. BIBLIOGRAPHY Сarlson,Е. A. 1983' Cепеs' Rаdiаtiсlп,апd Sсlсiеtу:Тhе Lifе апd Work of H. .[. Мuller.Ithaсa,NY: СornеllUnivеrsitуPгеss. Мr.rllеr,H. J' 1968. Studiеsiп Gепetiсs:ТЬе SеlесtеdPаpеrsof H'.|, Мullеr. Bloоmingtorr: IrrdianаUnivеrsit1, Prеss.[Mullеrsеlесtеdехсеr.Рts fronrmost of his pаpеrs,аnd this Ьсlokсontainsa ссlmplеtе ЬiЬliogrаph1' сlf his works.] -Е'А,С.

7.'.з

Natural histоry Nаtural history is thе сarеftrloЬsеrvation of nilturе, from а study of how soil сharrgеsfrom onе rеgion to anothеr to how fеmalе Ьuttеrfliеssеarсh for a suitаЬlе plaпt upon whiсh to lаy thеir еggs.Thе prасtitionеrs of natural history arе tеrmеd пttturаlists'and wеll Ьеforе sсiеntistsсaIlеd thеnrsеlvеsgеol. ogists сrr Ьotanists, indivlduals who studiеd thе nаtural world wеrе с;rllесl naturаIists.A truе naturаlist сr"rltivatеs ехpеrtisе in arеas from tlrе сoursе ot rivеrs to thе haЬitats of plants. Nаtural historу' was thе for.lrrdatiсrrr for tlrе disссlvеry of еvolr.rtiсln.Natu. ralists likе Jеan-BaptistеLamarсk and Еrasmus Darwin oЬsеrvеd thе haЬits of anirrrаls аrrd n
еvеn as lt appеars supеr and plants with digitаl l thе distriЬution of plаnt гathеr than survеyors'ir ral fеaturеs havе сhangе In partiсular, as сlinlatе r a l i s t sa г е p l a y i n gс r i t i с а organisrrrs in rеsponsе tt arе providing thе raw m tati()n tсl а rаpidly сhanр BlвLIoGRAPHY

Bаrtram,W., and F. Hагpе Е d i ti г , п A . t h е n sU : niv HсilldoЬlеr'B.,:rndЕ. O. \ Ехp lorаtiсlп.СаmЬrid W i l s o n ,F . .o ' 1 9 9 4 .N а t u r

Nаturаl Selеction а

Philip Slrеppard's Nаturс just Ьеfсlrеthе сеntеnary а nrаjor сonrriЬution to t not lеast thеir lЪllow Ьio sеlесtion was norv a fulI languagе of Thomas Ku faсt, and lndееdгhе rеv saying that although thе .

thе Ьook is disаppointin btrt ..in survеying mсldеr it is muсh lеss satisfасtor еvеryonе аgгееd,Ьес:lus Thе work ехеmplifiеs w а s с а l l с d г h е s y r r г h е t it Darwinism. First, thе сo tion undеrpinnеd Ьy lVIе 50 yеars aftеr Меndеl's Wеrе nor widеlу knoш,tt sеntials. Thosе intеrеstеd tion, puЬlishеd fivе yеar and Frarrсis Criсk, пrаrkе howеvеr, not only is DN Ьr.rtthеrе is also a wholе work of pеoplе likе Riс| lесulаr diffеrenсеsin
N a t u r a IS е l е с t i с l ann d H е r е d i t y еvеn аs it appеars supеrfiсiallymuсh сhаngеd.Naturalists doсumеnt animals аnd plants with digital imagеs rathеr than paintings anсl drawings and map thе distriЬution of plаnts and animals with gеogrаphiс information systеms rathегthаn survеyors' instrltmеnts.Altlrough thе tools tlsеd tO dеsсriЬе natrrrа| fеaturеslrzrvесhangеd,thе rrееdto do sсl and thе vаlшеin doing so rеmaitr. In partiсular' as сlimatе сhangеs zrnd humаn aсtivity аltеr landsсapеs' naturalists arе playing сritiсal rolеs in doсumеntingсhangеs in thе distriЬutions of organisms in rеsponsеto thеsе altегationsand through thеir doсumеntation irrе providing thе ri]w matеrial for sttrdyingwhat may Ье :r nеw еra of adaptаtiOnto a rapidl,vсhanging еarth' lf naturе'fronr a study of how soil ow fеmalе buttеrfliеs sеarсh for a s. Thе prасtitionеrsof natural his.е sсiеntistsсаllеd thеmsеlvеsgеoliеd thе naturаl lvorld wеrе сallеd )еrtisеin irrеasfгom thе с
BlBLIoGRAPнY Bartraпl,W', and L-.Harpеr. |998. Thе Trаuеlsсlf WiIIiаmВ.lrtrапI:Nаturаlist's Еditioп.Athеr.rs: Univеrsityof GеorgiaPrеss. НolldoЬlеr,B., аnd Е. O. \Иilsоn. |994. .|oпrпеуto thе Ants: А Storуof Sсiепtifiс Ехplсlrаtitlп. Prеss. СarтЬridgе'MA: BеlkllаpPrеssоf HаrvагdLJllivеrsity -].Т, Wilson,Е, o, 1994.Nаturаlist.Washingttlll' DС: IslandPгеss.

Nаturаl Sеleсtion аnd Herеd,b/ (Philip М. Shеppard) Philip Shеppard's Nаturаl Sеlесtiotlапd Herеdity, whiсh аppеarеd in 1958' just bеforе thе сеntеnary of Сhаrlеs Dirrwin's Оn thе ()rigiп of Spесiеs,was a rlajor ссlntriЬutiollto thе еffort Ьy Britislr еvolutioniststo pеrsuadеpеoplе' nоt lеast tlrеir fеllсlw Ьiologisrs' rlrat thе thеory o[ еvoluti
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Nаturаl Тhесlklgу \Х/ithhis foundatiсln now givеn, Shеppard goеs ()n to disсuss a numЬеr ()f importаnt issuеs in nеo-ontologiсal еvolutionary studiеs.Partiсulаr attеntion is paid to polymorphism-thе wаys in whiсh natural sеlесtion сan ilt thе samе timе hold diffеrеnt forms in a population. Muсh of this naturally draws on Shеppard's own work, partiсularly thе studiеs сlf srrails thet hе had donе еarliеr in thе dесadе' with fеllow Darwinian A. J. Сain, in thе Oхford сountrysidе. Shеppard had spеnt a yеar in thе lаЬoratory of ThеodсlsiusDсlЬzhansky in Amеriсa, and it is pеrhаps Ьесausе of this that hе is not еntirеly dismissivе of gеnеtiс drift as a сausal faсtor in еvolution, :rlthoughthе strong imprеssion givеn is that it is natural sеlесtionthat геally сounts in dеtеrmining thе gеnеtiс сomposition of populations. By thе 1975 еdition Shеppard is еvеn lеss kееn on drift, although hе doеs admit thаt it might nlattеr in prсltсin еvolцtion. Othеr topiсs that gеt major disсussion aге thе еvolutifNаturаl Sеlесtitlп(19з0) and wеrе mеrrtionеdlit. tlе in thе lеading Works of Amеriсan еvolutionists. DoЬzhanskу,s Gепetiсs апd the Оrigiп of Spесiеs(third еdition, 1951 ) has vеry littlе on n-rimiсry,and еvеn that is gorrе Ьy thе timе of thе dе faсtсl fourth еdition, Geпеtiсs of thе Еuсllutioпаrу Proсеss (1970). l,еwontin, a Мarxist сonvеrt' has somеwhat сontеmptuously rеmarkеd that thе Еnglish intеrеst in Ьuttеrfliеs,thе сhiеf sourсе of information aЬout mimiсry, rеflесtsthе dilеttantish,uppеr-сlassna. turе of Еnglish еvolutionary Ьiсllogy (sееLеwontin |974). With good rеаson' A. J. Сain (of vеry humЬlе origins) rеасtеd vеhеmеntly against this. But for thosе intеrеstеdin thе сultural faсtors that influеnсеsсiеnсе,if thе еmphasis is put only on partiсlrlar proЬlеms, Shеppard'svеry attraсtivеlywrittеn littlе Ьook is highly suggеstivе.It is vеry muсh writtеn Ьy irn Еnglishman who lovеs his сountrysidе and thе dеnizеns thеrесlf. BIBLIOGRAPHY DоЬzhansky'T. l951. Gcпеtiсsапd thc Оrigiп of Speсlсs.3rd еd.Nеw York: СolumЬiaUnivеrsityPrеss. Fishеr' R. A. 1930. Тhе GепеtiсаlТbесlrуоf Nаturаl Sеlесtiсlп.Oxford: ()хford UnivеrsityPrеss. Kuhn, T. |962. Tbе Struсturеof SсiепtifiсRеt,olutitlпs. Сhiсаgo:Univеrsitуof СhiсagoPrеss. Lеwontin,R. С. 1974,Thе С}епеtiсtsаsisrlf ЕuсllutillпаrуСhапgе'Nеw York: СolumЬiаUnivеrsityPrеss. Rееs,Н' 1958.Rеviеwof NаturаlSеlесtioпапd Hcreditу.Неrcditу'12:522_52З. Shеppаrd,P. М. 1958.NаtttrаlSelссtiotlаlld Неrcditу.l-ondot.t: Нutсhinson. -i4.R.

Natural thеоlogy Thеology dеals with our knowlеdgе of thе naturе and ехistеnсеof God. Rеvеalеd thеology is thе arеa that trеats of
faitlr аnd authority, Ье on thе сross filr our sil t h е а r е a t h а t t r с l t t чt l i . еxists nесеssаrilyfгom ural theсllogiсalсlaim. In thе Сhristiаn rеlrg сllogy. Howсvеr, еspес always had аn imptlrtа thеology, and famouslr ехistеnсе of God, аs wt stаnd his naturе. Prott susрiсiсln Ьut hаvе gеn AngliсаnСhurсh pаrti thority of thе Саtholiсs traditionally givеn natu Еvolutionary thеory' in sevеrаl rеspесts.onе miraсlеs. Маny natur miraсlеs-Ьrеа ki ngs сlf of thе deity. \й/atегсouJ so. L{сrwеvеr,аny sсiеn supposеs thаt thе worl< thеory supp()rtsthе uЬi In thе faсе of this oЬ h a v е Ь е е n t a k е n .o n t h Ьеtwееn thе ordеr of na proсееd aссording ttl I Еvolutionаry thеory do t h е y w i l | Ь е r а г е .l l p o i n Ье arguеd that mir:rсlеs a mattег of mеaning. J physiсal risе frсlm thе dс still livеd. Еvсllutionаry Anothеr plaсе whеrе сomе into сontaсt is thе tеnсе of God is thе ехisr and Ausсhwitz. No аIlhappеn. Darwinism sее posits a r-rЬiquitousstru wаys throughout thе lrv o n е r е s p o n s еm i g h t с t l f е v i l , n a m е I y г' h а tC r l that God сould havе сr Gсld dесidеd rrot tсl lеt h that pеoplе would nеvе thаn firе without pain.

Nаtиrаl Thcologу d gсlеsоn to disсuss а numЬеr of ) n а г ys t u ( , | i еl\).a r t i с r r l aаr t t е n t i o n liсh nаtural sеlесtiоn сatl at thе ion.Мuсh of this naturally draws tudiеsof snails that hе had с]onе r A. J. Саin, in tlrе oхfсlrd сoun)oratoryof ThеodсlsiusDoЬzhanе of this thаt hе is not еntirеly in еvolrttion,although thе strong ln thаt геаllyсourrtsin dеtеrminBy thе l975 еditiorr Shеppard is т i t t h а t i r m i g h t m i l t t е ri n p r o t е i n arе thе еvolution оf dominаnсе, э wе suгеly sее somеthing of a lf major intеrеstto Ronаld Fislrеr п ( | 9 З О )a n d w е r е m е n t i o n е d l i t . utionists.DсlЬzhansky,sGепetics i 1 ) h a s v е r , vl i t t l еo r r m i m i с r у . а n d to fouгth еditiсln,Gепеtiсs сlf tbe Мarхist сonvеrt' has somеwhat r intеrеstin Ьuttегfliеs,thе сhiеf ltsthе dilеttantislr,uppеr.сl:lssnalwontin |974).With good rеаson, 1 vеhеmеntlyagainst this. But for influеnсеsсiеnсе,if thс еmplrasis rd's vеry attraсtivеlywrittеrr littlе t wгittеn Ьy an Еnglishman who еof.

tlf Spесiсs,3rd еd.Nеw Yoгk: tнrаl SсlcсtЙlп.oxitlгd: ()хtord 'lutioпs.
Yсlrk:

I Неrеditу.Hеrеditу 12: 522_52З. : еrе dit1,.[,tlndon "..'.,'''.'.n:n,. o.

naturеand еxistеnсеof Goсl. Rеur undеrstandingof God thгough

faith anс{authoritv, Ье this authority thе сhurсh сlr thе BiЬlс..That Jеsus diеd on thе сross for otlr sins is a rеvеаlеdthеologiсal сlaim. Naturаl thесllogv is thе aгеzlthat trеats сlf сlur trndеrstandingof Goс{ througlr rеason. Тhat God еxistsnесеssarilyfrсlm his vеry dеfinititlrr(thе сlnгologiсalargumеnt) is a natu r r I t h с o l < l g i с саllа i m . In tlrе Сhristiarr rеligion rraturalthеology takеs a Ьaсk sеirtto rеvе:llеdthеology. Howеvеr, еspесially givеn thе Grееk influеnсе on Сhristianit1,,it hаs always lrad an importаnt rolе. Сatholiсs partiсularly m:rkе muсh of r.ratural theologv,аnd fаnlously Sаint Tlrсlmаs Aquinаs € ] llvе a sеriеs of proofs of thе еxistеnсеof God, as wеll as disсussiorlsof how wе might rеasonaЬly undеrstand his naturе. Prсltеstantshavе rеgardеd rеason in геligion with morе suspiсion Ьut havе gеnеrаlly allowеd somе plaсе for nаturаl thеolog,v.Thе AngliсrrnСhurсlr partiсulаrlv, sееkingа middlе r,vаyЬеtwееnthе еxtrеmе iruthority сlf thе Сatlloliсs and thе ехtrеmе ЬiЬliсalism of man1,Protеstatrts'hаs traditionаrllygivеn natural thесllсlgya signifiсantplaсе. Еvoltrtionar1,thесlгy,сspесiа[IyDаrrvitrisnl, irrrpingеstln trагuг.tltlrеolog1, in sеvеrаlrеspесts.onе oЬvious pоint of tеnsion ()ссurs()vеrthе еxistеnсеof miraсlеs. Many natural thеologians hаvе аrgtlеd that thе ехistеtlсе of mirасlеs-Ьrеakings of thе lаrvs of natuге-points tо thе асti.,.еintегvеI-ltIon of thе сlеity.\Wаtеrсould not havе Ьееrrгurnеd into winе lrаd God not donе so. Howеvеr, any sсiеntifiсthеrсlег of gгасе. Noгmаlly thе rvorld doеs proсееd aссordirlg to law, lrut somеtimеs God fееls thе nееd to rПtеrvеnе. Еvоlutionary thеory doеs not provе th:rt mirасlеs i.rrеimpоssiЬlе, only that thеy will Ье rarе, а point aссеptеdЬy tlrе Ьеliеvеr' on thе otlrеr hаnd, it сan Ье erguсd that rтiгасlеsdo not nесеssаrrily imply a Ьгеakirrgof law. It is morе а mаttег of mеaning. Jеsus's rеsurrесtion' for instаnсе, did not involvе a physiсal risе fronl thе dеad Ьtlt thе fееlir.rg in thе hеаrts of his disсiplеstl-rathе still livеd. Еvoir-rгionary tl-rеr-rl1, way in whiсЬ God сould havе

7.57

7.'8

Nаtиrаl Тhеrlklgу сrеatеd thе living world was thгough a mесhanism likе sеlесtion,and hеnсе hе саnnot Ье Ьlаmеd for its Ьad сonsеquеnсеs.(Kitсhеr 2007 rтakеs this сritiсism, that Darwinism еxaсеrЬatеsthе proЬlеm of еvil, and Rusе 2001 аrguеs thаt it may not Ье quitе suсh a prсlЬlеm for thе Сhristian.) Thе majtlr plaсе whеrе еvolutionary thеory, Dаrwinism in partiсular, сomеs into touсh with natural thеology is thе quеstiсlnof dеsign (Rusе 2003). From Plаto on, it was rесognizеd that thе living world is not random Ьut shows сomplехity, an intеgratеd аnd funсtioning сomplехity, for еxamplе' thе hand аnd thе еyе and thе nosе. How сould this Ье' givеn that normally Ьlind laws lеad to randomnеss? only thrсlughthе intеrvеntion of a dеsignеr, сOrтlеsthе rеply. This аrgumеnt was piсkеd up Ьy Сhristiаns, Saint Thomas paгtiсularly, and madе thе Ьasis of thе most сonvinсing of thе argumеntsfor t h е е х i s t е n с еo f G o d : t h е l i v i n g w o r l d i s a s i f d е s i g n е d ;t h i s i s Ь е с a u s еi t i s dеsignеd,and thе dеsignеris God. Philosophеrs' most partiсularly David Humе, showеd that in major rеspесts' еvеn if thеrе is a dеsignеr,it сanntlt Ье muсh likе thе Сhristian god. Apart from anything еlsе, why stop at onе dеsignеr?Howеvеr, Humе had to admit that it doеs sееm аs though thеrе is somеtЬingat work. Using a vеrsion of what is known as thе argumеnt to thе Ьеst ехplanati
It should Ье mеntioпс t е l Ii g е n t D е s i g l lT h с t l r i s r likе naturе of thе living thаt hеnсе wе must mai Although mеmЬеrs of th Ье idеntifiеd with thе Сh of thеm. As might Ье ех1 sion of ..сrеationismlitе. onе should rrеvеr invсlkе arе just not nееdеd in еv is rеquirеd. (Sее DеmЬs thе lеading сontrovеrsia In сonсlusion, it must rethеr tгump tгaditiоn just historiсаl intеrеst.Г thе dеsignlikе naturе of plaining. Мorеovеr, lik рhoгiсаl languagе of dе Adа1l tаtiсlп апd Nаturаl is produсеd as thе funсt to sеrvе that funсtion, l сonsсiсlus dеsign. Thе dt fсlr a сеrtаin gllаl or fuг v o l v е d w а s f a s h i o n е dЬ y bеautiful and historiсаll Тhе еyе was aЬovе all t} soп1еthingthat had ttl h е y е с o u l d n o t h a v ес o m е Ьitеs, thosе long-gonе п m i l l i o n y е а r sa g o a n d l a s fliеs (sее figurеs on pagе thаt it is сomplех, with l on рagе 761).Why is th on thе proЬlеm rеаlizеd Сhristiaan Huygеns had if you Want to avoid сh сausе thе diffеrеnt сomр i n d i с е s ) .N a t u r е Ь е a t t h t s o n a n d L е v i - S е t t i1 9 7 5 Сritiсs of univеrsal Dа and StеphеnJay Gould (

wronghеadеd sсllution;Ь mеr. Natural thеology lе prесisеly what should Ье a now-outmodеd thеоlog

Nаturаl Thеologу rnism likе sеlесtion,and henсе с е s . ( K i t с h е r2 0 0 7 m a k е s t h i s ' o Ь l е r ror f е v i l , a n d R u s е 2 0 0 1 т for thеСhristian.) cry, Daгwinism in partiсulaг' quеstionof dеsign (Rusе 2003). ving woгld is not random Ьut 'ning сonrplехity' for ехamplе, rld this Ье' gil,еr.rthat normаlly r thе intегvеntionof a dеsignеr' rp Ьy Сhristians, Saint Thonrаs :onvinсir-rg of thе argumеnts for f d е s i g n е dt:h i s i s Ь е с e u s еi t i s t m е , s h o r v с dt h a t i n m а j < l гг е lе muсh likе thе Сhristiаn g
It should Ье mеntionеd thаt thеrе is t
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l-_-:=:_\ i------j

-/:\-

spесilrlеnfronr Bohеmiз). TriloЬitе (Раrаdoхidеsgrdсilis,Мiddlс (]ar.nbrian

Top: Rеn6 Dеsсаrtеs(/ef сhromаtiс aЬеrration.Bс and Lеvi-SеttiI975.)

вlвLIoGRAPHY

TriloЬitе еУe (Rееdops stеrпbеrgi, DсvсlttitrпtriltlЬitс frсlrl l}tlhсmia).

Сlаrkson' Е. N. K.' and R. Dеsсartеsand Huvgеn Dаwkins,R. 1986.Тhе Blt 1995.А Riuеr()u Dеn.rЬski,\й/.A., and M. R СamЬridgе:Сambrid Gould, s' I. 1997. Thе Dar n o . 1 0 :З 4 - з 7 . Kitсhеr, P, 2007. Liuillg tu Nеw York: oxford Ur .!7. P a l е y , [ 1 8 0 2 ]1 8 1 9 .N a Rivington. Rusе, М. 2001. Сап а Dаr а п d R с I i g 'iп, ' С a m h r 2ОО3.Dаrшiпапd MA: Harvаrd Univег

Nаturаl Theologу

Upрr lеns unrt

Intralеnsaг Ьowl V

*l

i l г i а l l s l . t с с i r r l е n i г t l t l - tB o h с m i а ) .

Тсlp:Rеnё Dеsсаrtеs(left) and Сhristiaаn Hr.rygеns(right) shr.мtrrg how to avoiсi сhromatiс aЬеrrаtiоn. Bсlttotll:сross-sесtions.o1 triloЬItееyеs. 1г.3,,-,сlаrkson а n d L е v i . S e t t |i 9 7 5 . \

вlBLloGRAPl{Y

г r i ] t l Ь i t с f г t l m 1 3 t l h с l - r r i )a.

Сlarkson' Е. N. K.' and R. Lеvi-Sеtti. 197.5.TriloЬitе еyеs and thе optiсs of Dеsсartеsirnd Нu1'gепs.Nаturе 254: 66З-667. Dаwkins' R. 1986. Тbе Btiпd Wаtсhmаkеr. Nеw Yоrk: Norton. 1995. А Riuеr out of Еdeп. Nеw York: Bаsiс Books. DеmЬski, W. A', and NI. Rusе, еds' 2004. Debаtiпg Dеsigп: Dаruliпlo DNА. СarnЬridgе:СamЬridgе Univегsit1,Prеss. -I.hе Gou]d, S. J. 1997. Dоru.iniln funia-е.rt.lisгs. Nсш Ylrk Rеuiеtuоf Books 44, no.10: З4_37. Kitсhеr, P ' 2007 ' Liuiпg tl,tithDаrtaiп: Еuolution, Dеsigп, апd thе Futurе of Fаitb. Nе''v Yоrk: С)хforсj Urrivеrsitv Prеss. .W.. Pаlеv, (С,,llссtеd works, vol. 4). Lоndon: [1s02] 1s19. Nаtttr.l!Tht',l!t,g1, Rivington. Rusе, М. 2001. Сап а Dаru.liпiап Bе а Сhristiап? Thе Rеlаtiсlnsbip bеtшееп Scieпсе апd Rеligitlп. СaпrЬriс1gе:CапrЬridgе Univеrsity Prеss. 20ОЗ. Dilпl'iп апd Dеsigп: Dllеs Еuсllutilпt Hаuе а Purposе? СanrЬridgе, МА: Harvаrd LlnivеrsityPrеss.

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Thе Nature of Sеlесtion Thompson' D , \х/.19\7 . Оп Grotuth clпdFсlrm.СamЬridgе:СаmЬridgеUnivеrsitr, Prеss. !Иilliams' G. С. |966. Аdаpttltiсlпапd Nаturаl Sсlесtiott.Prinсеton,NJ: Prir"rсеtсlп Urrivеrsity Prеss.

-М.R.

The Nаture of SеIection (Е||iottSoЬеr) Thе Nаtиrе of Sеlесtion Ьy Еlliott SoЬеr is an important Ьook that addrеssеsa widе rangе of issuеs in thе philosoplry of Ьiology. It is onе of thе fеw ехamplеs of philosophiсаl work that hаs аttraсtеdthе attеrrtionof biologists (most notaЬly Еrnst Mаyr). Thе Ьook inсludеs disсussions оf thе tаutology proЬlеm, urritsof sеlесtion' adaptationism,сhanсе and proЬaЬility in еvolutionary thеory' thе еvolution of altruism, сausation, and foundational issuеs сonсеrning sсiеntifiс ехplanation in thе Ьiologiсal sсiеnсеs.Hеrе wе сan disсuss only a fеw highlights. Onе of thе пrost important distinсtions that SсlЬегnrakеs in this Ьook is thаt Ьеtwееn sеlесtioп of and sеlесtiсlпfor,In his siпplе ехamplе wе ссrnsidеr a toy that сontаins small grееn Ьеаds and largе whitе Ьеads.lй/hеntlrе ttly is shakеn' thе small Ьеads pass through a sеt of sm:rll holеs and arе thеrеЬy sеlесtеd. Thеsе Ьеads havе two propеrtiеs: thеy arе Ьоth small and grееn. But thеy arе sеlесtеdfor thе propеrty of Ьеing small; thе faсt that grееn Ьеadsarе sеlесtеdis mеrеly aссidеntal. So wе havе sеlесtionof small grееn Ьеads' Ьut sеlесtion for on|у thе propегty of Ьеing small. SoЬеr brings this distirrсtioI-rto Ьеar upon thе proЬlеnr of tlrе r.rnitsof sеlесtion. Using a disсussion in G. C. williams's Аdаptаtioп апd Nаturаl Sеlесtioп (1'966I,hе distinguishеsЬеrwееnindividual and grоup_lеvеladaptation in thе .Wе following way. supposе that a hеrd of dееr сonsists of fast individuals who arе aЬlе to еsсapеprеdators. As a rеsult, twо things happеn. Thе first is that in. dividual dееr survivе and rеproduсе. Thе sесond is that thе hеrd survivеs and rеproduсеs.But Ьесausеthе survival of thе hеrd is mегеly a Ьy-produсtof thе individuals'survival, this is a сasе in whiсh thеrе js sеlеctioпof fast hеrds.Тhis sеlесtion of thе fast hеrd is in сontrast to tЬe selесtioп for fast individuzrl dееr. In this way SoЬеr arguеs that thе dеЬatе aЬout gгoup sеlесtionism hingеs upon thе quеstion whеthеr thеrе сan Ьe selеcti
Nеandеrtals

Ргonounсеd Nаy_сz-dс реarеd as Nесrrrdеrtha of 18.56.Nеanс]еris th form wаs adoptс.dЬy t| posеr' Joасhinl Nеumа сhangе of ] 901, lvl-rе r r е а гD t i s s е l d o r f 'r l t l r vi and thе skеlеtorrwаs fс a сavе саllеd thе Fеld} might havе Ьеlоngеdtt in thеir trеatmеIrt,and Wеге not гес()vег(,(|. su whiсh thе origiпel Nеi C r o а г i а . F r l t r t с с l' t а I v 'l faсt, anothеr spесitnеn of GiЬraltаr irl t848,Ьr Сollеgе of Surgесlnsirl Thosе individuals hav. Nеаndеrtal skеlеttrlI аt thе сommunе tlf S;l logiсаl сOI1tеХtwith st nizеd to bе of thе sапr of Lе Moustiеr' dug in with thе Nеаnсlеrtаls; dioaсtivе еlеmепts to t not possiЬlе until aftе M t t t l s t е г i а nw l s r ' l t | с г modеrn-irppеlrringhun liеr than thе Nеaпdеrt in Java in 1891 and 1 Homrl) erесtus,All of t е v o lu t i o n a r v p с г s p е с r thе StrassЬurg itlll]t()m with thе асtuаl mесhil straightftlrrv:rrd piсtur j u s t a Ь o u t t h е l l l s tt i m е tionary pеrspесtivе. I n t h е s u m m е r < l f1 9 priеsts wеrе prrгsuing С h a p е l l е _ a u х _ S l r i n ti ns unсovеrсd :l сonr1.llеtе а сatеd thеir с1isссlvеry t. Franсе in Paris. AЬЬ6 B rесommеndеd thаt thс l

|',[eапdеrtсlls 7 6з СamЬridgе Univеrsity LmЬridgе: 'с,!ол.Prinсеton,NJ: Prinсеtorr

-М.R.

)r) mportantЬook that addrеssеs ll ;y. It is onе of thе fеw еxamplеs ntion of Ьiologists(most notаЬly thе tautology proЬlеm, units Of . in еvolutionarythеory' thе еvol issuеsсonсеrning sсiеntifiс ехn disсussonly a fеw highlights. at SoЬег makеs in this Ьook is lris simplеехamplе wе ссlnsiсiеr lWhеn thе toy is ;е whitе Ьеads. small holеs and arе thеrеby sе_ . а r е b o t h s m a l l a n d g r е е n .B u t rll; thе faсt that grееn Ьеads arе сtiоn o/ srrrallgrееn Ьеads, Ьut rе proЬlеmof thе units of sеlес_ dаptаtkп апd Nаtцrаl Selесtioп rd group_lеvеladaptation in thе : сonsistsof fast individuals who rings happеn.Thе first is thаt inlnd is th:rtthе hеrd survivеs and ,rd is mеrеly a Ьy-pгoduсt of thе :re ls sеleсtiсlпof fast,hеrds. This ;еlесtiottfor fast individu:rl dееr. : group sеlесtionismhingеs rrpon groups' This disсussion Suggеsts еmpiriсalquеstion'whiсh is not еll as thе rеst of SoЬеr'swork, is сal сonсеptsin suсh a way as to .thеrе aге suЬstantivеand dis_ гhеЬiologiсal sсiеnсеs,Ьut tlrosе riologistsgo aЬout thеir work.

narvsсепеry'SсiеttсеЗО5:46_47. ,паrуTherlrуiп Phiklsсryhiсаl , I е с t i , ,Pl tг,i n с е г с lN n J. : P r i n с е r o n

-Z.Е.

Nеandеrtals Pr
764

|']еапdеrtаls М a r с е l l i n B o u l е ( 1 8 6 | - 1 9 4 2 I , a p a l r o n t o l o g i s tw h o w a s а p r o f е s s o ra t t h е Mus6um d'Histoirе Naturеllе in Pаris. Boulе's monograph dеsсriЬing La Сhapеllе-аuх-Saintsсaпlе ()ut in thrее instаllmеntsin 191 1, 7912, and 191З and sеt thе tonе for thе study of human ..еvolution''for thе rеmaindеr of thе twеntiеth сеntury. Thеrе was nothing еvеn faintly еvolutionary aЬout it. Gustav SсhwalЬе wr()tе сlnе of thе rеviеws оf Bor"rlе'smonograph, noting thе anatomiсal еrrors Boulе had madе in his rесonstruсtion Ьut, сuriously еnough, ассеpting thе patеntly аntiеvсllutiсlnaryсast of thе intеrprеtation. Thе vеry nехt yеar World .JИаrI Ьrokе out' and onе of thе сasualtiеsof that сonfliсt Was thе еvolutionerу oriеntаtion in thе Gеrman trеatmеntof thе human fossil rесord. Bеforе thе wаr Ьсlth thе Gеrman and thе Еnglish litеrаturе trеatеd Nеandеrtals as аn еarliеr stagе in human еvolution that had Ьесomе transformеd through timе into аnаttlmiсally mсrdеrn fсlrm. Undеr Boulе's influеnсе thе Nеаndеrtаls wеrе pеrсеivеd in сariсaturе and rеgardеd as hаving Ьееn rеp l а с е d Ь y a n i n v a s i o n o f m o d е r n - a p p е a r i n gh u m a n s w h o с a m е f r o m . . t h е Еast.'' Thеrе is no arсhaеologiсal or anatomiсal support for this intеrprеtation, :rlthough it is thс viеw now hеld Ьy most studеnts of humаn ..еvolution.'' Various еstimatеsof Nеandеrtal staturе show malеs ranging from 764 t o 1 7 5 с е n t i m е t е r s( 5 , 5 , 't o . 5 . 9 , ' ) a n d f е m a l е sr a n g i r r gf r < l m1 5 2 t o 1 5 8 с е n t i m е t е r s( 5 ' 0 ' ' t o 5 ' l ' ' ) . M a l е Ь o d y w е i g h t h a s Ь е е nе s t i m a t е dt o r u n f r o m 9 0 t o 1 0 0 k i l o g r a m s ( 1 9 8 t o 2 2 0 p o u n d s ) .С r а n i a l с a p a с i t yw a s l a r g е rt h a n t h е modеrn avеragе Ьut pеrfесtly in proportiorr to thеir grеatеr Ьody wеight. Сlеarly thе Nеandеrtals wеrе сharaсtеrizеdЬy a dеgrееof skеlеtalrOЬustnеss .With and musсularity wеll Ьеyond thе morе rесеnt human avеragе. intеllес. tual and linguistiс сapaЬilitiеs proЬaЬly at modеrn lеvеls' thе Nеаndеrtаls quаlify as an arсhaiс form of Homo strpiепs. Thе сonvеrsion of Nеandеrtal into modеrn human form was aссomplishеd Ьy а rеduсtion in thosе manifеstatitlnsof roЬustnеssas a rеsult of tесhnologiсal innovations that allowеd thеm tсl gаin suЬsistеnсеwith lеss ехpеnditurе of еffort. Analysis of traсе еlеmеntsshows that thеir intakе of animal protеin was approхimatеly thе samе аs that whiсh сharасtеrizеsthе wolf. Thе usе of traps and snarеs' howеvеr, grеatly rеduсеd thе anrount of еffort nееdеd to Ьring food homе. Most mutations rеduсе thе trait that thеy сontrсll, and whеn sеlесtion that maintains r
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This drawing showsho thе modеrn stаtеЬy a r arсhitесturеwhilе thе с unсhangеd.Thе Nсаnd сlf approхimatеly70,0С Palеolithiс mаlе from tl yеars ago' аnd а rесеn

в|вLIoGRAPHY

Brirсе, С. L. 1995а. I]iсl in thе еmеrgеnсеof 7t1-72t. 1 9 9 5 Ь .T h e S t а g P r е n t i с еH а | i . 2ООО.Еuоlиtioп Prеss. Morin, Е. 2004. Latе Plе еvolutionary aрproa сlf Мiсhigаn, Ann A Trir.rkaus,Е., аnd P. Shiр Мclпkiпd. Nеr,vYoгl

Мasatoshi (b

N4asаtoshi Nеi has Ье sity sinсе 1990.Hе oЬ

Nel ,t who was a profеssor at thе l's monograph dеsсriЬing La е n t si n | 9 | 1 , 1 9 7 2 , а n d 1 9 1 3 tion'' for thе rеmaindеr of thе tly еvсllutionaryaЬout it. Gusэulе's monograph' noting thе rесonstruсtionЬut, сuriously lry сa5tof thе intеrprеtation. .d onе of thе сasuаltiеsof that э Gеrmаn trеatmеntof thе hunglish litеrаturеtrеatеd Nеanthat hаd Ьесomе transformеd r. Undеr Btrulе'sinfluеnсе thе J rеgardеd as having Ьееn rе..thе humans who сamе from эal support for this intеrprеta. ,.еvolulst studеntsсlf human show malеs ranging from 1'64 l r a n g i n gf r o m 1 5 2 t o 1 5 8 с е n bееnеstimatеdto run fгom 90 al сapaсity was largеr than thе to thеir grеatеr Ьody wеight. . a dеgrееof skеlеtalrobustnеss human avеragе.\й/ithintеllес. nodеrn lеvеls, thе Nеandеrtals human form was aссomplishеd Jstnеssas a rеsult of tесhnologwith lеss ехpеnditurе rЬsistеnсе rt thеir intakе of animal protеin thе wolf. Thе usе of Laraсtеrizеs :hе amount of еffоrt nееdеd to hе trаit that thеy сontrol, and rеlaxеd, its manifеstations will геduсеthе intеnsity of selесtion r с i а t i o nN е а n d е r t а l sw е r е u s i n g rеduсtion in tooth sizе саn Ье i n е o f 1 % е v е r y2 , 0 0 0 y е a r s u n /еarsag(). rat thе Nеandеrtals diffеr morе thе avеragеdiffеrеnсе Ьеtwееn )еtwееnNеandеrtals and living )NA diffеrеnсеsЬеtwееn popu:еs within pсlpulations of сhim-

TЬis drawing shows how Nеandеrtaiсraniofaсialfoгm was сonvеrtеdintсl thе mоdеrn statеЬy a rеduсtionof thе dеntitionаnd its supportingfaсial arсhitесturеwhilе thе сontoursof thе Ьrain сasеrеmainсdеf{есtivеly unсhangеd.Thе Nеаndеrtalis thе Lа Fеrrassiе1 malе of southwеstеrnFranсе, ovеr an еarly Uppеr 70,000 yеarsagо' supегimpсlsеd of approхirrratеly Palеolithiсmalе from thе Сzесh RеpuЬliс,Piеdmosti З' of 25,000 to 29,000 yеаrsago' and a rесеntFirеroеIslandsmalе.

BIBLIOGRAPHY Br;rсе,С. L, 1995a. Bio-сultural intеrасtitrnand thе mесhirnismof mosaiс еvolution ..modеrn'' mоrphologv. Аmеriсап Aпthкфologist 97, na.4: in thе еmеrgсnсеof 7 1 1-721 . 199.'Ь. Тhе Stаgcsof Humап Еuolutirlп..5thеd. Еnglеwсlod Сliffs, NJ: PгеntiсеHаli. 200О. Еuolutirm itt ап Aпthropoklgiсаl Viеш' Wаlnut Сrееk, СA: AltaМira Prсss. population intеrасtion in wеstеrn Еuropе: An Мorin, Е. 2004' l,аtе Plеistс.lсеrrе еvolutionаry approaсh to thе оrigins of modеrn humans. PhD diss.,Univеrsity of Мiсhigаn, Ann Arbor. Trinkаus, Е., and P. Shiprnan. 1992. Тhе Nеапdеrtаls: Сhапgiпg the Imаgе of

Мапktпd.Nеw Yoгk:AlfrеdA. Knorэf.

Nеi, Мasatoshi (b. 1931) Masatoshi Nеi hаs Ьееn Еvan Pugh Profеssor at Pеnnsylvaniа Statе Univеrsity sinсе 1990. Hе oЬtirinеdhis PhD from Kyottl Univеrsity in 1959. Hе was

765

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Nei аssistant profеssor, Ky()to Univеrsity, 19.'8_1962; gеnеtiсist,Nationаl Institutе of Radiologiсаl Sсiеnсеs,СhiЬa' 1962-1969; assoсiatеto full profеssor, Brown Univеrsity, 1969_IL)72;and profеssor,Univеrsity of Tехas' HoLlston' 7972-t990. In еvolution thеrе is a grеat еffсlrt tсl infеr thе еvolutiсlnaгy rеlаtiсlnships among organisms.Тhis Ьranсh of Ьiology is сorтmonly known as systеmatiсs. In thе 1960s еvolutionistsstartеd to usе Ьioсhеnriсaland molесulаr diltil, mainly protеin еleсtrophorеtiсdata' to study systеmatiсs;еlесtrophorеsisis a tесhniquе usеd to mеasurеthе moЬility of a protеin on a gеl. |n |972 Nеi dеvеlopеdа mеthod for еstimating thе gеnеtiс distanсеs Ьеtwееn populations from еlесtrophorеtiс data. This mеthod soon Ьесamе thе standard mеthod in tlrе study of еvolutionaryrеlatiсlnshipsamong populationsrlr сlosеlyгеlatеdspесiеs,and thе mеasurе oЬtainеd Ьy usе of thе mеthod is known as Nеi's gеnеtiс distanсе.Thе rеason for its popularity is that thе mеthod givеs an еstimatеof thе ntrmЬеrof amino aсid diffеrеnсеs Ьеtwееn two protеins and thr-rsthе dеgrее of protеinsеquеnсеdivегgеnсеЬеtwееn thе two populirtions frorn wlriсh thе two protеins wеrе takеn. Thеrеforе, this nrеasrrrеis еasу t
ohta, Tomoko (Ь.

Tomoko Ohta has Ьееn tion for undеrstandingr dееp undеrstanding of spесiеs with сreativе ml fundamеntal quеstions: A studеnt of Кеniсhr turnеd to Japan aftеr сo mous сollaboration Witl Kimurа'' in this volumе) of nеutral allеlеs(i.е.,allе riеrs). In 1971 sЬeand Ki thе nеutrаl thеory сould с in natural populations, a еssays prеsеntеd a сompl potеntial powеr as an е work providеd a thеоrеt protеin variation to еstlп l а t i o n s i z е ( a m е a s u r еo i gеnеration) to thе usе of In еxploring thе nеutr out that nаtural pсlpula prеdiсtеd. Тo aссоunt f variants would Ье slight hypothеsis lеd to diffеrе alignеd Ьеttеr with oЬsе Ohta also did pionее hеmoglobins. Thеsе fam arе major parts of thе gе iliеs in еvolution and dе gеnеtiс drift would proп among сopiеs within а s and among populations Ьеr of thе Amеriсan Aса forеign assoсiatе of thе nizеd Ьy thе еmpеror of

'"'.Ъ*;.ill.Y;Ж;.]J*IT;::*l;;.',:;;x'':*"!;h",il,i|:)ni.o^!,ii_o -w.-Н.L.

962; gеnсtiсist,Nаtionаl Insti)69; assoсiatеto fu11profеssor' , Univеrsitytlf Tехas, Houston' г thе еvolutionaryrеlaгionships l t n n t t l n lk1l l t l w n e s s y s t е m a t i с s . niсaland nrolесulaгdаtа, rnаinly сs; еlесtroph(lrеsisis а tесhniquе а gеl. ln l972 Nеi dеvеiopеd a )еtwееn populаtitlns from еlесstandаrdmеthod in thе stшdyof lr сlosеlyrеlatеdspесiеs,and thе vn as Nеi's gеnеtiссlistаnсе.Thе rеsаn еstimi1tеof thе numЬеr of and thr-rsthе dеgrее of prсltеinl n s f r t ' t l tr rh i с h г h с t w o p r r l t е i n s Thе mеthod also hаs tndеrstаnd. hсlds.In l979 Nеi dеvеiopеd а lе suЬstitutionspеr sitе Ьеtwееn lata.This was anothеr milеstonе pеd sсvеralехсеllеntlnеth()dsfor пs pеr sitе Ьеtц,ееntwo DNA sеrе anсJN. Saitou dеvеlopеd thе volution;rry(phylogеnetiс)trееs. hods rn phylogеnеtiсrесonstruсly оn phylсlgеnеtiсstudy usеs this t lеadеriп thе study of mсrlесular s mеthodshavе hеlpеd сlarify thе and gеnсs.In additi
lаr F'uсllut iоtt. Сarт bridgс: lns.Аmеriсап NаturаIist \06:. . . lf o r l т u d 1 i n gg' . е n е t ivс r r i : l г l с l l il t t gs ,lf thе Nаtilпшl Асаdemу of lg mеthod:A nец, Inсthоd for \irltlgl апd F't,lllиtirlп4: 4О6-42"5.

-w-H.L.

Ohta, Tomoko (b. 1933) Tomoko ohtа has Ьееn a lеading figurе in dеvеloping a thеorеtiсal founda. tion for undеrstandingmolесular еvolution. In hеr work shе has сomЬinеd a dееp undеrstanding of pattеrns of molесular variation within and among spесiеswith сrеаtivе mathеmatiсаl modеling to approасh somе of thе most fundamеntal quеstions about molесular еvolution. A studеnt of Kеniсhi Kojima at North Сaгolina Statе Univеrsity, ohta rеturnеd to Japan aftеr сomplеting hеr doсtoral dеgгее io t967 and Ьеgan a fa..Мotoo mous сollaЬoration with Motoo Kimura (sее thе alphаЬеtiсal еntry Kimura'' in this volumе). Thеir еarly еssaysdеvеlopеd modеls for thе dynamiсs of nеutral allеlеs (i.е.,allеlеs that do not сonfеr diffеrеnсеsin fitnеsson thеir сarriеrs).In |971 sЬeand Kimura puЬlishеd пvo landmark еssaysthat showеd how thе nеutral thеory сould сonnесt mutation ratеs,lеvеls of protеin polymorphism in natural populаtions, and long-tеrm ratеs of amino aсid suЬstitutions.Thеsе еssaysprеsеntеda сomplеtе piсturе of thе nеutral thеory and dеmonstrаtеd its potеntial powеr as an ехplanation for sееmingly disparatе phеnomеna. This work providеd a thеorеtiсal foundation for sеvеral linеs of геsеarсh'from using protеin variation to еstimatе populаtion paramеtеrs suсh аs thе еffесtivеpopulation sizе (a mеаsurе of how many individuals aсtually сontriЬutе to thе nеxt gеnеration)to thе usе of molесular variation in phylogеnеtiс studiеs. In ехploring thе nеutral thеory furthеr, Ohta was among thе first to point out that natural populations harЬorеd morе rarе аllеlеs than nеutral thеory prеdiсtеd. To aссount for this pattеrn' shе postulatеd thаt somе molесular variants would Ье slightly dеlеtеriousand othеrs modеratеly dе|еtеrious.Hеr hypothеsis lеd to diffеrеnt statistiсаl distriЬutions of fitnеss еffесts that wеrе alignеd Ьеttеrwith oЬsеrvеddata on polymorphism and ratеs of еvolution. ohta also did pionееring work on еvolution in multigеnе familiеs likе thе hеmogloЬins. Thеsе familiеs arе sеts of tandеmly rеpеаtеd сopiеs of gеnеs and arе major parts of thе gеnomе. ohta rесognizеdthе importanсе of thеsе familiеs in еvolution and dеvеlopеd most оf thе еarly thеory that prеdiсtеd how gеnеtiсdrift would promotе divеrgеnсеin thе DNA sеquеnсеsof thеsе gеnеs among сopiеs within a singlе individual, among individuals in a population, and among populations. In 1984 Tomoko Ohta was еlесtеd a forеign mеmЬеr of thе Amеriсan Aсadеmy of Arts аnd Sсiеnсеs.In 2002 shе was еlесtеda forеign assoсiatе of thе U.S. National Aсаdеmy of Sсiеnсеsand wаs rесog. nizеd Ьy thе еmpеror of .|:rpanas a Pеrson of Сultural Меrit. 767

768

On Crowth and Form в|BLloGRAPHY Kimura, М., and T. ohtа. |971. TheorеtiсаlAspесtsof PopulаtioпGепеtiсs. Prinсеton,NJ: PrinсеtonUnivеrsityPrеss. ohta, T. t98О. Еuolutitlпапd Vаriаtiсlпof МltltigепеРаmiliеs.Bеrlin:Springеr-J.T. Vеrlag.

Оп Groшth аnd Form (D'Arсy Wеntwоrth Thompson) Оп Groшth апd Form' first puЬlished in 1.917,is still in print as an aЬЬrеviatеd vеrsion in papеrЬaсk' with an introduсtion Ьy StеphеnJay Gould. This in itsеlf marks thе Ьook as somеthing rеmarkaЬlе.It is hard to think of сlthеr Ьiologiсal tеxts of a similar vintagе that havе a сomparaЬlе еnduring sсiеntifiс rеlеvanсеi apart from volumеs rеprintеd primarily for thеir historiсal intеrеst' onе thinks of Darwin's works and not muсh еlsе.Thе Ьoоk is and has always bееn sееn as thе distinсtly idiosynсratiс opus of a highly ессеntгiс Ьi. .sИеntworth ologist, D'Arсy Thompson (profеssor of zoology at St. Andrеws Univеrsity in Sсotland, 1917_1948),who is еffесtivеlyrеmеmЬеrеdsolеly on thе strеngth of this Ьook. Why has it survivеd? Thе Ьook prеsеnts thе сasе for an aссorrnt of Ьiologiсal struсturеs Ьasеd on mесhaniсal and physiсal prinсiplеs. It aspirеsеspесiallyto а mathеmatiсal mеthodology; сhеmistry hardly fеaturеsat all. Using an аstonishing sеriеsof ехamplеs aсross thе whole rangе of phylogеny and of sсalеsof magnitudе,it shows how various typеs of Ьiologiсal ..form'' сan potеntiаlly Ье ехplainеd Ьy various typеs of physiсal forсеs. Topiсs сovеrеd inсludе sсaling, ratios o{ surfaсе to volumе, growth сurvеs' сhromosomе pattеrns' сеll struсturе and сеll division (еxplainеd in tеrms of surfaсеtеnsion),multiсеllulaг arrays (asin honеyсomЬs), shеlls, horns, flowеr pattеrns (ana|уzеd in tеrms of FiЬonaссi sеriеs),zеЬra striping, and shaping of еggs and Ьonе struсturе (ехplainеdas adaptations to imposеd mесhaniсal strеssеs).Thе сlosing сhaptеr is undouЬtеdly thе Ьеst known and thе sесtion most dirесtly rеlatеd to еvolution. It dеals with Thompson's ..transform'' mеthod-a dеpiсtion of diffеrеnсеs in morphology of rеlatеd spесiеs (е.g.,fish) or wholе struсtllrеs'suсh as skulls, in thе form of сoordinatеd gеomеtriс dеformations (familiar nowadays in thе guisе of сomputеrizеd morphing) (sее figurе).Thr naturе and vаluе of this ..mеthod'' is disсussеd еlsеwhеrе(Hordеr 2005); it is aсtually no morе than a dеsсriptivе dеviсе and is not Ьasеd on' or an indiсation of, any dеvеlopmеntal or еvolutionary mесhanisms as suсh. Among prеsеnt.day apprоaсhеs to еvolution, thе сlosеst сomparisons arе morphomеtriсs and еspесia1lyallomе. try' whiсh, through J. S. Huхlеy' was thе most dirесt and ехpliсit dеvеlopmеnt that arosе out of Thompson's Ьook. Thе survival of this arсhеtypiсally сlassiс book is аll thе morе puzzling Ьесausе it is distinсtly datеd in Ьoth stylе-it is writtеn in sсholastiс and еven litеrary modе-and сontеnt. It datеs from a timе whеn gеnеtiсs was in its infanсy, Darwinian еvolution Was aсtivеly Ьеing quеstionеd in favоr of Lamarсkism, and thеrе wеrе many gaps in undеrstandingof Ьasiс сеll Ьiology. Мorе surprising still, Thompson adoptеd positions on thеsеthеmеsthat havе

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Left: out|ine of thе porсu (О rt h аgсlriscus mсllа).Nt any knowlеdgе of thе ma rеpliсatеhis findingsаnd fгom thе fish form on thе 1948,1064.1

provеd to bе ..wrong'' ( sis was saltationist.Thе s o n ' s r е а l ' m i s s i o nw a s stil1 prеvalеnt-to show l i n е s o f t h е a l r е а d ys с i е physiсs. How is it possiЬlе th ago? Onе faсtor might r with somе instantly stri up Thompson's mеssagе ProЬaЬly morе signifiсa ologists wеrе inspirеd Goldsсhmidt, Julian Hu danе, and Реtеr Mеdaw a symЬol and idеal of l proЬlеms of Ьiology. T сious swееp and rangе

on Gгowth and Foгm ts of PopulаtioпС]еttеtiсs. пe Fапiliеs. Bеrlin:Springеr-

-J.Т'

worth Thompson) ,' is still in print as an aЬbrеviэn Ьу StеphеnJay Gould' This Ьlе. It is hard to think of othеr a с o n r p a r a Ь l ее n d u r i n g s с i е n lrimarily for thеir lristoriсal innuсh еlsе.Thе Ьook is and has с opus of a highly ессеIrtгiсЬissor of zoolоgy at St. Andrеws .fесtivеlyrеmеmЬеrеdsolеly on ? Ьasеd of Ьiologiсal strr"rсturеs :еsеspесiallyto a mathеmatiсаl . Using arr astonislringsегiеs of y and of sсalеsof magnitudе, it t'' сan potеntially Ье ехplаinеd tvеrеdinсludе sсaling, ratios of mе pattеrns' сеll struсturе and sion),multiсеllulararrays (as in ana|уzedin tеrms of FiЬonaссi rd Ьonе struсturе (eхplainеd as Тhе сlosingсhаptеr is undouЬtlirесtly rеlatеd to еvolution. It - a d е p i с t i t l no f d i f Г е r е n с е si n vholе struсtцrеs,suсh as skulls, rtions(familiarnow:rdaysin thе ). Thе naturе and valuе of this l5);it is aсtually no morе than а indiсzrtionоf, any dеvеlopmеnong prеsеnt-dayapproaсhеs to omеtriсsand еspесiallyа-rllomеost diгесt and ехpliсit dеvеlop. ook is all thе morе puzzling Ье; writtеn in sсholаstiс and еvеn timе whеn Е]еnеtiсswas in its зing quеstionеdin fаvor of Lа:rstandingof Ьasiс сеll Ьiоlogy. itions or-rthеsе thеnrеs that hаve

Diodon Left: out'|tneof thе porсupinе fish (Diodoп) , RigЙf: outlirrеof а sunfish (Оrthаgorisсиsmolа). Notе thаt Thompson was working intuitivеly, without an1'krrorvlеdgеof tl-rеmаtlrеmatiсsinvolvеd. Today' with сomputеrs, wе саn rеpliсatеhis findiпgsand havе a full undеrstandingof the movеsnеedеdto go frorn thе fislr form on thе lеft tо thе fish {orm on tЬе right. (FrсlmThompson 1948,1064.) provеd to Ье ..wrong'' (sееHordеr 2005). Нis position rеgarding phylogеnеsis wаs sаltаtionist.Thе Ьook is in еvеry wаy a produсt of its timе. Thompson's rеal mission Was-as a сountеr to thе vaсuous vitalistiс еxplanations still prеvalеnt-to show that Ьiologiсal phеrromеnаwеге ехpliсаblе along thе linеs оf thе alrеady sсiсntifiсallyhighly dеvеloped disсiplinе and mеthods of physiсs. Нow is it possiЬlе that this Ьook is as influеntial now as it was 90 years ago? Onе fасtor n-rightwеll Ье thе illustrations.Thе Ьook is riсhly illustratеd witlr somе instantly striking аnd mеmoraЬlе piсturеs thаt in thеmsеlvеssum up Thompson's mеSsagе;thеу сan Ье' and hirvе oftеn Ьееn, rеadily rеproduсеd. PrоЬaЬly morе signifiсant is thе way in whiсh a stеady suссеssionоf kеy Ьiologists wеrе inspirеd Ьy thе work. Aсross sеvеral gеnеrations (Riсhard Goldsсhrrridt,JLrlian Huxlеy, Еvеlyn Hutсhinson, Alan Turing, J. B. S. Haldanе, and Pеtеr Меdаwar to StеphеnGould and John Bonnег) thе Ьook was a symЬol and idеal of a rigorous sсiеntifiс approaсh to many of thе major proЬlеms of Ьiolоgy. Thе Ьook appеalеd all thе morе Ьесausе of its audaсious swееp and rarrgе. Tlris list inсludеs thе nаmеs of somе of thе most

769

on thе origin of Spесiеs influеntiаl biologists of thе twеntiеth сеrrtury,many of rvhorт madе Thomp. son widеly kr-rownthrough thеir popular writings. Thе Ьook nright appеar to Ье of most dirесt rеlеvanсеto dеvеloprnеntalЬiologists,Ьut thеy havе rarеly ..holists''(morphologistsаnd еspесially takеn it up; it has appеalеd mainly to palеontologists)or on mеthodologiсal grounds (Ьiorrrathеmatiсiаns). In an agе dominаtеd Ьy molесular Ьiology, gеnеtiсs' and p
Оп the Оrigin of Species (Charlеs Darwin) Сhаrlеs Dаrwin's mаjor wоrk, Оп thе ()rigilt rlf Speсiеslэу Меапs tlf NаturаI Sеleсtioп, or thе Рreseruаtioп of Fаuспtred Rасеs itt thе Strиgglе for Lifе' was puЬlishеd in NovеmЬеr 1859. Thеrе wеrе 1'250 сopiеs, and it was sold out on thе first day (morе prесisеly,thе puЬlishеr sold аll оf thе сopiеs to Ьooksеllеrs at his Ьiаnnual salе).Darwin startеd immеdiаrеly to prеpaге a sесond еdition, and in аll thеrе wеrе six еditions, of whiсh tlrе last appеaгеdin 7872. Thе work is dividеd into two parts. In thе first pаrt Darwin prеsеntеd his mесhanism of natural sеlесtion and offerеd rеasons to think it plausiЬlе.Hе pointing out thе suсdid this first through analogy with artifiсial sеlесti
naturаl sе|есtiсlnpr
its inrpсlгt:lrrсеand pсlrr Thеrе wеrе majtlг сh D:rrwin puЬlishесl,vеr1 thе truth of еvolutior.. strЬjесtеdtсl stringеntsс ous. Tlrе 6rst was tl-rаtI today ll,сluld саll a thеt o Ь v i о r r sr h n t n n l е с h а n ond oЬjесtion,Ьаsеdс hеаting po\\'еrtlf thе sцr а mесhirtlistnаs sеlесtr As wе now know, th. Меndеl's thеory сlf hег сountеrесl.Тhе sесrlndr f е с t o f r а d i o a с t i v еd е с а Was not thеn kn
Unfсlгtunatеly,thе еrr еgant ехtеndеd еssayЬrr that todа1.'srеadеrsgеn BIBLIOGRAPHY

Dаrwin' с. l859' ()п thc

P rе sеruаt itltt llf F аullt' Мurгit\..

, 'r 1 t 1 I e S e .f 1 1 n P е с k h a mс, d . P h i l а d е Riсl.r:rrds. ll. .|',аnd М. Rt of Spес:iеs.'' СаmЬгid

ontogеnу аnd Phу

In Опtсl3iеп1,апd Рh1,| growth oГ thе iгrdividuа lristor1саl sttrсlvtlf rесll twееn stagеsin dеvе|op Thе anаlogy Ьеtwееl ing'' was familiilr to Aгl this iсlса rь,аrs rеslrаpеdi

Ontogеny and Phylogеnу many of whoin madе Thomprgs.Thе Ьook might appеar to liologists,Ьut thеy havе rarеly (morphologistsand еspесially Js (biomathеrтatiсians).In an :s' аnd pоpulзгiоn rhinkingivеrsitiеs-this Ьook stаnds toy problеms and ехplanatory Еесtionwith whiсh it has Ьееn .s7еntworth rе fасt that D'Arсy ms of Rеlаtiue Groшtb (19З2)

lridgе'МА: tsеlknapPrеss of nnеss,еd.' Lаndmаrk \Yritiпgs |940, 82з-832. Amstеrdam: London:Nlеthuеn. ,g Biolоgiс,аlDеUеk)pmепt u)ith з, MA: Наrvаrd Univеrsity Prеss. orm' 2nd еd. СamЬгidgе:

.,-o'jfl/.'. rsion. СamЬrid*.'

arwin) of Spесiеsbу Мeапs of Nаtиrаl :еs iп thе Strugglе for Life, was l50 сopiеs,and it was sold out sold all of thе сopiеs to ЬooknmеdiatеlytO prеparе a sесond ,hiсhthе last appеarеdin 1872. first part Darwin prеsеntеd his ]asonsto think it plausiblе. Hе ;еlесtion,pointing out thе suсwеnt on to show (in an arguМalthus) how a strugglе for populations to a lеvеl grеatеr l s u p p o r t .а n d t h е n h o w ' g i v е n ads to diffеrеntial survival and lесtion. lpliеd his mесhanism aсross thе lсt' Ьiogеographiс distriЬutions, logy, аnd othеrs-showing how

nаtrrralsеlесtitlnprovidеs ехplаllatiсlnsin all tЬеsеаrеas and how, сonvеrsеly, thеsеarеasсonfirm thе tгuth аnd pсlwеrof sеlесtion.This is not so muсh a сirсular argulnеnt аs ()l1еthаt is rеirrfoгсing.Thе argumеnt is known tесhniсally as a сoпsiliеllсе of iпduсtioпs. |t Was pГom()tеdЬy thе Еnglish philosophеr of sсiеnсеWillianr lVhеwеll, and it was from this sourсе thаt Dаrwin lеarnеd of its impсlrtanсе аr]d powеr. Thеrе wеrе m:rjor сhаngеs in thе suссеssivееditions of tЬe Оrigin. Дfter Darwirr puЬlishеd, vеry fеw in tlrе sсiеntifiс сtlmtnunity сontinuеd to dеny rhе truth of еvtllution. Htlll,еvеr, Darwin's thеory of natural sеlесtion was suЬjесtеdtO stringеntsсiеntifiсanalysis,and two objесtions sееmеdvеry sеrious. Thе first w:ls that Darwin had no adеquatеthеory of hеrеdity-whаt wе today would сall a thеor1.tlf gеnеtiсs-and without suсh a thеory lt Was not сlЬviottsthat a mесhanisrnlikе sеlесtionссluld lravе a lasting еffесt.Thе sесond oЬjесtion, Ьasеd orr physiсists' саlсulаtitlns aЬout suсh things as thе hеatingpowеr of thе sun, wаs tlrat thе еarth was far too yоung for so lеisurеly a mесhаnism as sеlссtion tсr havе takеn еffесt. As wе now know, tlrе first сlЬjесtionwas wеll takеn, аnd it was not until Mеndеl's thеory of hеrеditу'Was rеdisсovеrеdthat this oЬjесtion сould Ье сountеrеd.Thе sесond oЬjесtiсlnWas not wеll takеn, Ьесausеthе hеating еffесt of radioaсtivе dесay (and thе сtlnsеquеntmuсh oldеr agе of thе еarth) Was n()t thеn kn
Оntogenу аnd РhуIogeпу (StephеnJay Gould) |n Опtogeпу апd PЬу,logеиya dеtailеd :rnalysisof thе rеlirtionshipЬеtwееn growth of thе inсiividual
771

772

ontogеny аnd Phylоgеny to intеrprеt studiеs of thе dеvеloping еnrЬryo. Karl Еrnsf vоn Baеr:saw inсrеasing divеrgеnсе from а сomпlon lnitial Ьodv plаrr as vеrtеЬratеsсlеvеlop distinсt adult lЪrms. Еrnst Haесkеl ассеptеdD:lrwin's еvidеnсеfсlг еvolution Ьut not thе adеquасy of his mесhаnism. Не infеrrеd that strr.rсtшrаl innova. tion involvеs thе addition of nеw tеrminal stagеsto Ontogеny.Thе rеsulting rесаpitulation of abbrеviatеd anсеstral ftlrms Ьесаt-t-lе сoс]ifiеdas thе Ьiogenеtiс laW' from whiсh anсеstralrеlationshipsсould Ье infегrеd and lost forms prеdiсted, thеrеЬy ovеrсoming dеfiсiеnсiеsof tlrе fossil rесord. In thе аbsеnсеof a satisfaсtorythеory of individual vаriatiсlnand hеrеdit,v, Нaесkеl's idеas gainеd widе сurгеnсy in thе post.DaгWinian еra. Hаесkеl insistеd that геrmirraladditiсlrrand гесapittrlationц.еrеthе rnесharrism,thе еffiсiеnt сausе of еvolutionary сhangе. Gould shows that this thеllolvingta[rlе.

Somаtiс dеvеlopnrеnt

Rеproduсtivе mаturirtion

Ассеlеrаtioп

N o с h а r r g еi n t i m i n g

No сhаngеin timing

Ассеlеrrttiсlп

Rеtаrdаtioп

No сharrgе in timing

No сhangеin timing

Rt'tаrdаtiсlп

TЬird, using a сloсk m arе еnd mеmЬеrs in a сс агraiyzеd quantitiltivеl) r е r n sa n d е х p е r i m с n r i' l volvеd. In short, lrе lаid dеvеlopеd mсrrеfсlгmаlI Thе most сritiсal сlf r l t r t i o n n r 1i.m p l i с а г i r l r l sl . mсlrphiс' juvеnilizеddеs stгonglv in favor tlf еаr risе to novеl сombinatr< dеvеlopmеnt' This proс and popr spесializzrti
A l Ь е r с h ,P . ' S . J . G с l t r l dG, . onto!]еnyand phylсlg G o u l d , S . J . 1 9 7 7 .О п t о g a Prеss. М с N a m а r a 'K . ' | . 1 9 9 7 S .l Deuеloplnепt.Bаltimо

oparin, Alеksandr Shift in рattеrn Rесаpitulcttirlп (Ьу ассеlеration) Pаеdomorphosis (Ьy trunсаtiol-r)= P ю gепеsis Pаеdllmorphrlsis (Ьy rеtaгdatit>n)= N еotеltRесаpitulаtiсlп (Ьv pгolongation)

Alеksandr l. oparin, a l fluеntiaI pionееrs of thе l in thе Soviеt Union in 19 ( 1 9З 6 ) ' С ) p a г i n p r е s е n t е a r t h . O p а r i n . s i d е а si n i mепtal in еstаЬlishiпgrn Rеalizing thе еnоrmсl fiеld of Ьioсhеmistry, o of thе origin of lifе frorт

Оpаriп l. Karl Егnst von Baеr saw in'dv plan as vеrtеЬratеsdеvеlop )аrwin'sеvidеrrсеfoг еvolution r.rfегrеd that struсtur:rltnnovа'gеsto ontogеny.Thе rеsulting Ьесamесodifiеd as thе Ьiogесluld Ье infегrеd and lost forrr-rs thе fossil rесord. ]ividual vаriation and hеrеdity, ost-Darwiniаr-r еra. Haесkеl irrn wеге thе mесhanism, thе еffiLowsthаt this thеory dеpеndеd virirlism tlrаt unасknсlu.lеdgеd -Ь' Ё | t l

^+.Ь^t

dL

lIl с r L

r( iir -I .r L .

roпr graсе Ьесausееviс1еnсеaс_ еirrJt аn}'st.tgсin гhе lifе с1.сlе. , е da s р е r m i s s i Ь l ее x с е p t i o n st o iould arguеsthat it was woгk in lf Jr4еndеliаn gеnеtiсsthаt madе nd doеs aсt on all stаgеsof thе c prеdiсtivеpowеr' thе pattеrns his_ t and thоsе tlf еvolutior-rirry lirrgсlаssifiсations.Тlrеsе inhiЬlеd hеtеroсhrоny. trееmajor сontriЬutirlnsthat rеir,v.First, hе shiftеd thе foсus of ; of dеvеlopmеntalmесhanisms ganismsand irrfеrrеdfrom anаliесond,hе еstaЬlishеda simplе lеnt and thе onsеt of rеproduсt rе:rltеrms, аgainst сloсk tiпlе. s of hеtеroсlrronyсan еасh аrisе lgraphiс and есolоgiсal сonsе_ in thе followirrgtaЬlе.

Tlrird, usirrga сlосk mсldеl, hе shorvеd thаt rhе саtеgoriеs of hеtеrtlсhrony arе еnd mеmЬеrs in a сontinuum of potеntial еvolutionагy сhangе that сan Ье analyzеd quantitаtivеly, using mеthods of allomеtry to study еvсllving pаttеrns and ехpегimеntsin dеvеlopmеntalЬiology to еiuсidаtе thе pгoсеssеsinvolvеd. In short, lrе laid thе groundrvork for a сalсulus of hеtеroсhrony, latеr dеvеlopеdmoге fi>rmallyin сonjunсtion with a group of сollеaguеs. Thе most сritiсаl of thе distinсtior-rs Gould еltrсidаtеd,it-ltегms of its еvсllutionary impliсations, is thаt Ьеtwееntwo proсеssеstlrat givе risе tO pаеd
oparin, AlеksandrI. (1894-1980) Shift in pаttеrn Rесаpitиlаtkln (Ьy ассеlеrаtion) Pаеdomorphosis (by trunсationI = Prсlgеtlеsts Pаеdomorphosis (Ьy rеtardation) = N еoteпу Rесаpitulаtit-lп (Ьy prоlongatiorr)

AlеksandrI. oparin, a lеас1ing R u s s i а n Ь i o с Ь е m i s t ,W a s a m o n g t l r е m o s t i r l fluеntiаl pionееrsсlf thе stLrdyof tlrе еmеrgеnсесlf lifе. Irrа Ьooklеt puЬlislrеd in thе Soviеt Union tn 192-4,and latеr in a tтoге dеtailеd Ьook, Оrigiп of Lifе (19З6|' С)parin pгеsеntеdhis ЬrеaktЬrоugh tlrеory ()n thе origirr of lifе on еarth. Opаrin's idеаs insрirеd пlanУ геsеarсlrеrsworldwidе arrсlwеrе itrstru-l mеntаl in еstaЬlishingin thе 950s a sсiеntifiсfiеld dеvotеd to thе suЬjесt. RеaIizing thе еnormous сomplеxity оf thе living сеil, геvеalеdЬy thе rising fiеld of Ьioсhеrnistry,Opzrгir-r rеjесtеd Ьсrrhsiпrplistiс Inесlranistiсsсеnaritls of thе origin of lifе from lrlattеr and vitalistiс сlaims of an unЬridgеаЬlеgаp

77З

774

О1lаriп Ьеtwееn mattеr аnd Iifе. Instеаd,rеlуing oll nеW аsrгonomiсаlаnd gесllogiсаl tlrеoriеs irnсl сlаta, Ilе formtrlatеd а t.tаtuгalistiсеvolutiOnaгv sсеllаrio that postulаtеd spесifiс physiсoсhеrтiсirlсonditions' сonduсivе to lifе, On thе primordial еarth. Oparin first suggеstеdthе synthеsistlf organiс сomptlr"rnds in thе rеduсing, thаt is, hydrogеn-riсhprimordial atпrosphеrеon еаfth, spurrеd Ьr' various sourсеsof еnеrgy.Thеsе сompounds wеrе dissolvеdin thе first sеas ..soup'' tсl fоrm an orgаrriс and lаtеr ltndеrwеntсIrеrrriсalеvсllutiоn toш,ard morе сomplех lllonomеrs аnd polymеrs. Sir-nilагidеas wеrе inсiеpеndеntly formulatеd in tl 1929 artiсlе Ь1, thе British gеnеtiсistJ. B. S. Hаldаnе. Although Haldanе's iпrpaсt on thе study сlf thе origin of lifе was сomparativеly nrinor, thе сonrbir-rаtionof tеnеts rеlаting to thе rеduсing primordial atmos;llrеrе,thе soup, al-rdсhеmiсal еvoltrtionwаs latеr tratrrеdthе С)parin-Haldanе hypotЬеsis. Sonrе l-ristoriansof sсiеnсе raisес]tlrе intriguing sugt]еstionthat Oparin,s and Haldirnе's Marxist аffiliations (as wеll as similаr iпсlinations of othеr pionееring rеsе:rrсhеrsin thе fiеld) сontriЬutеd ttl thеir сlrigin-of-lifе сonсеption. Rеflесting thе гhеn-сontеmporar'vdisсovеry сlf еtrzymеsand пrеtаЬoliссyhonrеostаriсlliltllrе lisrт,and diviс]еd into ..offs;lring.''Through inaссlrratеinlrегiti.rпсе of thе original orgаt-tizirtion аnd primitivе nаtural sеlесtion among сolllpеting off. spring, thеsе struсturеs, Opаrin Ьеliеvеd' сould еvolvе into morе сomplех еntitiеs. Еvеn in thе 19.50sand latеr, wlrеn thе naturе
(

в|BLloGRAPH\

Frу, I. 2000. Thс Еmеrg Nеw Brunswiсk,N. . Н а l d a n е J, . B . S . 1 9 6 7. 242_249(Appеnd puЬlishеdiпThе R, K а m m i n g aН , . 1 9 8 8 .H сontехtof dеr,еloр B i o s p h е r е1 8 :l - 1 1 O p a r i n ,A . I . [ 1 9 3 6 11 9 PuЬliсations. 1967. TЬe origi |99_zз4 (Appеrrd рuЬlishеdin Мosсс

organismiс еvolu

Whеn wе think of еvс -5.50 rnillion yеаrs,th

history that гесords sееd-produсing to flo fish, lаnd-dwеlling vс this agе аrе likе thе ti latе сhaptеr of а vеrу Ьrian lifе, thаt ехtеrr -З.5 Ьillion yеаrs ago Thе Phanеrozoiс wt and plants, many rеla all fairly familiar, еr,е ехtinсt. And thе гulеs dеmisе of myriаd spе tion. But thе world o multiсеllular organisr sprеad miсrobеs and l Ье sееn without usеol of thеsе rvеrе сyаnoL thrivе in rеmarkaЬIyr isrns еvolvеd littlе or tinсt. Unlikе thе histo followеd a diffеrеnt sс

ЕARLY PRЕсA|

Thе most oЬvious ant is thе typiсally mound pagе 777), finеly lavе torrr) that arе сOmmo frсlm roсks as olс.las .

Оrsапismic Еurllutioп аttd Rаdiаtion bеfore thе Саmbriап tеWi]stronomiсilland gеologiсаl istiс еvolutiс.lnarysсеIlario that ns, соnduсivеto lifе' On thе pri. lthеsisof orgarriссompotrnds in al atmosphеl.е()n еafthJ spurrеd ds wеrе dissolvеdin thе first sеas wеnt сhеmiсаl еvolutior-rtoward rnilаr idеas rvеrе indеpеndеntly gеnеtiсistJ. B. S. Haldаnе. Al. origin of lifс u.as сompirrativеly l tlrе rеduсinе primorсlial аtnrolаtеrnanrеdthе Oparin_Haldanе d thе intriguing suggеstion thаt irs rvеll as sinrilaгirrсlinаtiсlnsof lntriЬutеd to thеir сlrigin-of-lifе гу of еnzvnlеsаrrd nrеtaЬoliс с'vnеostatiсnattlrеof Ьio1
BIBLIOGRAPHY Fry, I. 2000. Thе Еmergепсеof Lifе сlttЕаrth:А HistoriсаIапd SсientifiсОueruiеш' Nеw Brunswiсk,NJ: RutgеrsUnivеrsityPrеss. Haldanе'J' B. S. 1967' Thе originof lifе.In J. D' Bеrnal,Tbе Оrigiп of Lifе, 242-249 (AppеndiхII).London:Wеidеnfеldаnd Niсolsсln.(originally puЬlishеdin Thе RаtioпаlistАппuаl, 3_10, in 1929.) Kamminga'H. 1988.Historiсаlpеrspесtivеs: Thе proЬlеmof thе originof lifе in thе сontехtof dеvеlopmеntsin biologу. origins tli Lifе апd Еt',olutioпof thе B i с l s p h е r1е8 : 1 _ 1 1 . oparin, A. I. [1936l \95З. Оrigiп of Lfе. S Мorgulis,trans'Nеw York: Dovеr PuЬliсаtions. 1967.Тhеorigin
organismiс еvolution and radiation bеforе thе Сambrian !Иhеn wе think of еvolutiоn, wе think of thе dеvеlopmеlltof life ovеr thе last -550 rrrillion yеars, thе Phanеrozoiс еon of gеologiсal timе-that part of еагth history that rесords thе wеll.known progrеssion from sporе-produсing to sееd.proсluсingto flowеring plants and from аnimals without ЬaсkЬonеs to fish, lirnd-dwеlling vеrtеЬratеs'and thеn Ьirds and mammals. Yеt roсks of this agе arе likе thе tip of an еnorrnous iсеЬеrg' for thеy rесord only a Ьriеf latе сhaptеr of a vеry muсh longеr еvolutionаry story' thе history of PrесamЬriarr lifе, that ехtеnds somе sеvеn timеs furthеr into thе gеologiсal past, to *3.5 Ьillion yеars ago (sееfigurе on page 776). Thе Phanеrozoiсworld was muсh likе that today, onе populаtеd Ьy animals and plirnts, marry rеlativеly largе, most spесi2rlizedfor partiсular sеttings, and all fairly familiar, еvеn thosе suсh as triloЬitеs and dinosaurs that arе now long ехtinсt. And thе гulеs of Phanеrozoiс еvolution' thе risе and thеn thе ultimatе dепrisе of myriad spесiеs' arе known to a||:spесiаtiott, spесiаlizаtioп, ехtiпctioп. But thе world of thе PrесamЬrian was vastly diffеrеnt. Instеad of largе multiсellular organisms' thе РrесamЬrian was dominirtеd by divеrsе widеsprеаd miсroЬеsand singlе_сеllеd аlgaе,virtually all of whiсh arе too small to bе sееrrwithout usе of a high-powеrеd miсrosсopе. Among thе nrost suссеssful of thеsе wеrе сyanoЬaсtеria, miсroЬial jaсks-of-all-tradеs that wеrе aЬlе to thrivе ir-rrеrnarkаЬly variеd sеttings.Моst notаЬly, many of rhеsееarly organisms еvolvеd littlе or not аt all ovеr Ьillions of yеars and havе nеvеr gonе еxtinсt. Unlikе thе history of Phanеrozoiс lifе, еvolution during thе PrесamЬrian followеd а diffеrеnt sеt сlf rulеs: s|'lеciаtion, gеnеrаlizаtiсlп, long-tеrm suruiuаl. ЕARLY PRЕсAMBR|AN L|FЕ Thе пrost obvious and еzrsilydеtесtеd fossil еvidеnсе of PrесamЬrian miсrobes is thе typiсally mound-shapеd stromatolitеs that thеy Ьuild (sееfigurе at top of page 777), finеlу layеrеd' morе or lеss сaЬЬagеlikеstruсtrrrеs(page 777,Ьottom) that arе сOmmon r,r,orldwidеin PrесarrrЬгianlirnеstonеs аtrd arе known from rосks as old as -3.5 Ьillion yеars (Hofлrann еt aL. 1999). Although most

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m i u r o ] r с - l r t l i l t \ t r () t l l . l t ( ) Тhllr wаr'v m;rtr - |.,l hi Mollrilnl, Ullitсtl Stltс' v с а r s . ' I d (B . f r . l l r r t h е , \

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(,аlсаrеous stroll].1tolitеsfilrlning trldаy at Slrаrk Bа1.,Wеstегn ALrstraIiа(A), сlсlsеly rеsспrЬlе fossil liп-rеstonсstrсlmаtolitеs (B) сli thе -2..] Ьillion-vеar-old Trаnsvaаl Dolomitе at Boеtsap' (Japе Provinсе, South Afriса. Thе gеoltlgiсal lrаmmеr сiгсlесl iп 1rаrt(A) sЬows tlrе sсаlс tlf Ьoth ph()tоs.

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777

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suсh struсturеs arе сomposеd of thе minеral сalсitе (whiсh, as it сrystallizеs to form limеstonе, dеstroys thе dеliсatе organiс-wallеd miсroЬеs that Ьuild thе stromatolitiс layеrs), somе Ьесomе pеtrifiеd Ьy finе-grаinеd quartz that сan рrеsеrvе suсh tiny miсroorganisms in ехquisitе dеtail (sееfigurеs hеrе and сln page 779). Suсh сеllular miсroЬiаl fossils arе known from hundrеds of Prесambrian dеposits worldwidе, thе oldеst pеtrifiеd in rсlсks nеarly 3.5 Ьillion yеars in agе (sее figurе on pagе 780; Sсhopf 199З)' RеmarkaЬly' many suсh miсrobеs' partiсularly anсiеnt сyаnoЬaсtеria(sееfigurе on pagе 781), appеar to havе сhangеd littlе or not at all ovеr litеrally Ьillions of yеars (Sсhopf 1994). Two lеssons aЬout еarly еvolution stand out. First, lifе еmеrgеdquitе еarly in thе history of thе planеt. Thе еarth, thе moon, and all othеr Ьodiеs оf thе

FilаmеntousсyanoЬaсtеriatЬrее-dimеnsionally pеtrifiеdin stromatolitiссhеrts of thе -8.50milliсln-yеaг-оld Bittеr SpringsF-
Sphеroidal singlеand сol pеtrifiеd in strorтаtrllitiс' Formаtion of SiЬеriа,Ru Dolomitе of SoutЬAustг Formation of NorthеrnJ arе mсlrphologiсallyindr For ехamplе,thе shеath еssеntiallyidеntiсaltсlthс (А) Еoeпtophуsаlis;(B| о (D) Gloесэсаpsa-likе сеll 1 (G) Еotеtrаhеdrioп.(Bar

solar systеm formеd *4 impaсts Ьy oсеan-vapo h a Ь i t a Ь l еo n l y - 3 . 9 Ь i l l for lifе .-З.5 Ьillion yеa a n d с а r Ь о n i s o t o p i сс v h а d Ь е с o m еа f l o u r i s h i еnvironmеnt had Ьесoг idly and was pеrhaps a

Саmbriап

Оrgапismiс Еuol,utioпапd Rаdiаtiott bеfсlrеthe Саmbriап

сitе (whiсh' i.rsit сrystirllizеsro vallеd miсrobеs thаt Ьuild thе y finе-grаinеdquartz that сan dеtail (sееfigurеs hеrе аnd on own fronr hundrеds of Prесamr rсlсks nеarl,vЗ.5 Ьillion yеars . Rеrr-rarkаЬlу'пlаnу suсh mifigurеon pаgе 781), i.lppеarto lions of yеars (Sсhopf 1994\. ' Fiгst, lifе enrегgеdqrritе еаrly on, and all сlthеrЬodiеs of thе

pеtrifiеdin stгсlmatolitiс сhеrts rаtion of сеntral AustraIia. ndistinguishaЬIеfrom mкldеrn riасеае.Fсlr ехаmplе, thе spirаl з m Ь | еt h е l i v i n g о s с i | | а t r l r i а с е a n in part (М), сomposеd of t r , , u t l . J е гdе r n l i r l а lс е l l . i s d t о i l l u s t r n t сс 1 ' r n с t h . r с t е r iiаn B, I, and J) Сеphаlophуtаrir-lп; l аnd L) Fi|iссlltstrictt-lsиs;(F) Неliссlпепtа: (|у|\

Sphеroidalsinglеand сolonial сyаnoЬaсtеriаluI-riсеlls thrее-dimеnsionally pеtrifiеdin stromatolitiссhегtstlf thе -1 Ьillion-l'еar-oldSukhayaTunguska Еormationof SiЬеriа,Russia (A_D); rЬе -770 millitln.vеаг-оldSkillogrrlее Doiomitс of South Australiа(Е);and thе *850 rrrillion-yеar-сlld Bittеr Springs Formation of Northеrn Tеrritory,Australia (F, G). Маny of thе fossilsshсlwtl arе morplrologiсallyindistingtrishaЬlе from modегnссlссоiс]al сyanoЬасtеria. For ехаmplе,tlrе shеath-еr-rсlosеd urriсеl[sshсlwrrin parts (F) and (D) аrе (}loеocаpsa(сf.}-oп pаgе 78l) еssеntiallyidеntiсtrI to thе living сhrсltlсoссaсеan (А| Еo eп tophуsаlis: (B) unnirmеdсhrtloсoссaсеa ns; (С ) G l o еodiпi rэpsis; (D) Gloеoсаpsa-likесеll pair; (Е) lrnnarnеdеrlshеаrthеd uniсеll;(F) Еоl-rgiсlп; (G) Еotetrаhеdritlп'(Barsfor sсalеrеprеsrnt10 цm.) solar systеm iсlrrnеd -4..5 Ьillion vеаrs ag(). Yеt thе еllrth' Ьес:1usеof е:rrly impaсts Ьy oсеan-vapсlrizingmеtеtrritеs,sееп1sto havе Ьесomе сontinuously haЬitaЬlе оnly -3.9 Ьillion уеars a8() (sееfiguге on pаgе 776).Fi.m еvidеnсе iсlr lifе -З'5 Ьillion yеаrs аgo-in thе fornl oI strtllnatolitеs,сеlIulаr fсlssils, and саrЬon isot()piс еvidеnсе of miсroЬiаl photosyntlrеsis-пrеаns that lifе had Ьессlmеa flouгishing suссеsswithin а sсаnt 400 nrillion yеаrs aftеr thе еnvironnlеnt hасl Ьесolnе сlеtrrеnt.Еvidеntlt' liiЪ.sсlrigin Oссurrеd morе rаpidly arrd Was pеrhaps appгесiаЬly еasiеr than has gеnеrally Ьееn imirginеd.

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Fоur sресimеns tlf thс се[lLr[arIilаlnеnttlLrsfсlssiImiсrсlЬе Pritltаеuifilum .1l|l()еnun1' am()Ilg tЬс oldеst fossils norv kllсllvn, pеtrifiеd in thе -3.46.i Ьillirln. Apех сhегt tlf llсlrtlrwеstсrn Wеstеrn Austrаliа' ln pаrt (D) an optiсаl 1.е.rг-tlld phottlmiсrogгaph оf ir spссitnеn is sholvrl togеthеr with its Ranrаn spесtrurn and its thrее-dimеnsiоnirl Rarnan imirgе (сlf thе аrеа dеnotеd Ьy thе rесtanglе in thе optiсаl photо), с1-rеrтiс:rl dаt:r thirt Ьy dirесt аna]уsis еstаЬlish thаt suсh еspесiallv аnсiеnt fсlssils.likе vсlr-rngеr pеrrifiсd fossils (sсс 6clrrеs on pagеs 77ll, 7 7 9 ' 7 8 | , а n d 7 8 3 ) ' a r е с ( ) | n p o s е rс]l f с а r Ь o l l a с е с l u sr , г ц J t l i сm i ] t t е r .

I,iviлg strсlmаtolitе-llrri a n d P r е с а m Ь r i a n f о s s i ]l t l in shelеy sсdimеnts (B, I) (F, [{). (А) I,у'пgbуа,с
()rgаnisпiс Еutllutiсlltапd Rаdiаtiсtп bеforе thе Саmbriап

]t'аг'lаг.iiYl;;e il rniсroЬеPrimаеuifilum n, pеtrifiеdin thе -З.465 Ьillion\ u s t r а l i aI.n p a r t ( D ) a n o p t i с a l hеrwith its Rar"r.ran spесtrumand r dеnotеdЬy thс гссtanglсin thе alysisеstaЬlishthаt suсh fossils(sееfigurеson pagеs778, ()rgаnlсmаttеr. :еOus

Living stromаtсllitе.Ьrrilding сvantlЬасtеriаfrсlm Baja, Мехiсo (A, С, Е, and G)' аnd PrесаmЬriаnfossil ltlok-аlikеsprеsеrvеdas flattеnеdorganiссomprеsslons pеtrifiеdin stromatolitiссhеrts in shаlеysеdimеnts(B' D) or thrее-dimеnsionally (F, H). (А| I,упgbуа,сomрaгеdwith (B) Pаlеolупgbуаfroпr thе -950 millionyеar-oldI,аkhirndaFormation сlf SiЬегia,Russia;(С\ S1lirиliпа,сomparеdwith (D) Неliсoпеmа from tlrе -8.50million-yеаr-oldМiroеdikha Formation of from thе SiЬеriа,Ilussiа;(||)Cloесlсаpsл,сomparеdwith (F) G|oесldiпiс-tpsls - 1 . 5 5 Ь i l l i o n - y е a r - o |Sdi r t k aF - o r m а t i oonf B a s h k i г i a R , u s s i a ;( G ) Е n t o p h у s а l i s , fг
781

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Оrgаnismiс Еuсllutiсlпапd Rаdtаtioп bе|.orеthе Сапtbriаlt

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Nеvеrthеlеss,dirесt еvidеnсесlf thе еrrrеrgеnсе of lifе is urrknown end may Ье gеolгеprinritir,е miсroЬiirl anсеstors). \й/ithin only a fеw hundrеd million yеars аftеr thе onsсt of еarth,s oxygеn. riсh еnvironmеnt' largе Ьallосlrr-shirpеdelgal uniсеl[s (aсritarсlrs)first ap. pеarеd, fossils tlf wЬiсh саtr llе hrrndгссlsof ll-tiсгlllrsасross' rrrtrсhlargег tlratl phyto;llarrk. nonnuсlеatеd prokаryсltеs(sс.сIigurе oll pagе 78З). I-argе.сеllесl

L а r g е - с е | l е dе u k a r у o t i с. с l t г Ь o t l a с е . l u ьl l | а с k s h а l SiЬеriа, Russizr (A); thе R u s s i а ( B ) ; r r n dt h е * 8 5 0 n t i l Ii o n - y е a r - о | dR с d k i n t (С| P tеr osp еfl rropsimor p

ton thаt livеd in offsht сornprеssion irr shalеsа tolitеs arе among thе е fossil rесord shor,vsthа o v е r а n е n o г t n о u sp е r i А l | е v i d е n с с5 u g , g е сеllеd algае rvеrе muсh with latеr lifе thеy еvol this thеrе is an еasy ехр геprсlduсеdеntirеly Ьy с с е p t f o г t r r t t t l l t i t l nеs э' с duсing in this way, thеy еvolvе :rt all. All organl loс:rl еnvironmеnt; oth ..|| nlightwеlIllе it nir ..Ьrokс.n'' Ьy mu do gеt

е Саmbriап :е of lifе is rrnknown and may Ье rvе dеstrtlyеdviгtuallу all roсks n fossiIrес
wегеkеv. Today's wсlrld is domЬut this Was not always truе' Ina l .2 0 0 4 ) l i f е g o t a l o n g q u i t е w е l l , Ьесartsеoхygеn и,as sсarсе аnd аеroЬiсmеtaboiiсmеаns to kееp ows thаt сyanoЬaсtеria,miсrtlЬеs prеsеntfar еarliеr (Sсh
Оrgапismiс Еuolиtiсlп апd Rаdiаtion bеfсlrеthe Саm|эriап

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Lаrgе-сеllеd еukllгуоtiсaсritаrсhsprеsеrvеdаS flattеnеdсоtrrрrеssiсlns in сarЬonасеоusЬllrсkshаlеsof thе 9.l0 rrliIlion-yеar.old LaklrandаFormаtion of Sibеria'Russia (A); thе -800 million-yеar-oldAkЬеrdin Есlгrnаtionof Bashkiria, Russia(B);ar.rdthе -850 million-yеar.oldМiroеdikha Formation (С) and *580 million-yеar-oldRсdkino Formation (D), Ьtlthоf SiЬеriа.(A and BI Kildiпеllа: (С) Ptеrospеrmсlpsiпtсlrphа; (D| Lеiosplпеridiа.(Birrsfor sсalегеprеsеnt10 цrт.)

ton that livеd in оffshorе Watеrs irnd' thеrеforе' wеrе rтаinly prеsеrvеd Ьr' сomprеssionin shalеs and siltsttlnеsrathеr than Ьy Ьеing pеtrifiеd in stromatolitеs arе amonr] thе еarliеst еukaryotеs known. Impoгtarrtly,howеvеr, tlrе fossil rесord sh<>lvs that thеy, likе thеir prokaryotiс аnсеstors' еvolvеd littlе -l.8 to -1 Ьlllion \.еilrsago. ovеr an еnornlolls pегiod of timе, frt>п.r AIl еr,idеnсеsuggеststhat in сеllrrlаr struсtufе thеsе еагl1,.еvolvеd singlесеllеd аlgaе rvеrеmuсh likе latеr.еvolvеdРhanеrozoiс lifе. Yеt in сompагison with latеr lifе thеy еvolvеd аt an inсrеdibly sluggish paсе (Sсhopf 1992).For this thеrе is an еasy ехplanation, namеly, that thеsееаrly асritarсhsproЬaЬly rеproduсеdеntirеly Ьy сloning (mit
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Оrgапismiс Еurllutiсlпаnd Rаdiаtioп bеforе thе Саmbriап systеmshavе many Ьioсhеmiсal rеpair mесhanisms,molесular proсеssеsthat сorrесt сhangеs сausеd Ьy mutatiсln аnd rеturn damagеd molесulеs to thеir original statе.Thе laсk of еvolutionary сhangеamong suсh сloning aсritarсhs' dеspitе thеir еukaгyotiс organization, thus makеs sеnsе.Еvolution is а rеsult of smаll сhаngеs that slip through thе systеm unfiхеd and thаt ovеr timе сan .Wе ultimatеly add up. sее thе rеsults of еvolution in thе fossil rесord only Ьeсausе of thе vastnеss,thе aЬsolutееnсrrmity,of gеologiсal timе. !Иhy and whеn did еvolution finally spееd up? Though no onе knows for сеrtain, thе Ьеst Ьеt for thе ..why'' is sеx. In and of itsеlf this advanсеd rеproduсtivе proсеss-Ьasеd on mеiсlsis(sех-сelldivision' an еvolutionary dегivativе of mitosis) and syngamy (thе fusion of gamеtеs' spеrm and еgg' to produсе a singlе-сеllеdzygotе that hаs a full сomplеmеnt of gеnе-сarrying сhromosornеs)-pгoduсеs nеw gеnеtiс сomЬinations in еaсh and еvеry offspring. Thе advеnt of sехual rеproduсtion would havе markеdly spееdеdthе dеvеlсlpmеntof nеw spесiеsthat Ьесausеof thеir novеl gеnеtiсsсould сompеtе and еvеntllаlly dominatе in haЬitats prеviously ownеd Ьy thеir nonsехual prokaryоtiс anсеstors' a dеvеlopmеnt wеll еvidеnсеd Ьy rRNA phylogenеtiсtrееs Ьasеd on molесulаr Ьiology. As for thе ..whеn'' of thе spееdup,fossils of uпiсеllular еukаryotеsrесord an abrupt major inсrеasе in еvolutionary ratеs -1 billion yеars ago (Sсhopf \992)' Мost linеagеsof highеr' multiсеllularorganismsdatе frоm thе so-сallеd СamЬriаn ехplosion of lifе, Ьеginning -550 million yеars ago. To еvolvе to this lеvеl, еvolution must havе spееdеdup in thе half a Ьillion yеars Ьеtwееn 1 Ьillion yеars ago and thе Ьеginning of thе СamЬrian. And еvolution did indееd aссеlеratе:phytoplankton gavе risе to multiсеllular sеawееdsЬy -850 million yеars ago (Buttеrfiеldеt аl. 1990); аnd primitivе protozoans' prеsеnt a s е а r l y а s - 9 5 0 m i l l i o n y е a r s a g o ( B l o е s е rе t a l . ] 9 7 7 ; P o r t e r е t a l . 2 0 0 3 ) , had Ьy *600 million yеars аgo lеd tсl dеvеlopmеntof soft-Ьodiеdmultiсеllеd animals (sееtop figurе
О,t

Thrее mеmЬеrsof thе lаr animals, prеsеrvеdas irnр yеar-old Pound Quartzitе symmеtriсalfossil possiЬ wormlikе animаl; (С) Sрr thiсkеnеdhеad shiеldp4;

тHE сAMBRIAN ЕxPLosIoN Although thе еvolr-rtionaryimpасt of thе grеat radiatiсln of lifе during thе СamЬrian pеriod hаs Ьееn rесognizеd sinсе thе timе of Darwin, its сausе rеmаins a puzz|e. At prеsеnt two major sсhools of thought сompеte. Physiсal sсiеntists(gеologists,palеontologists)look to major сhangеs in еаrth's еnvi. ronmеnt (thе worldwidе glaсiation of a ..snowЬall еarth,'' pеrhaps сouplеd with an aЬrupt risе in oХyЕ]еnaЬundanсе).In сontrast, life sсiеntists(Ьiologists, molесulаr Ьiologists) f:lv
Small skеlеtalfossils/СЙл PhanеrozoiсЕon of gеоlo million-yеar-old)Ajaх l,ir fragmеnts arе thought to sluglikе animаl. (Bar for s

hе Саmbriап ]anisms'molесular proсеssеsthat :turn dаmagеd molесulеs to thеir gе among suсh сloning aсritarсhs' makеssеnsе.Еvolution is a result m u n f i х е dа n d г h a t o v е r t i m е с а n lution in thе fossil rесord only Ье, of gеologiсaltimе. :d up? Though no onе knows for In and of itsеlf this advanсеd rесеll division, an еvolutionary dе_ 'n of gamеtеs' spеrm and еgg' to u I l с o m p l е m е n to f g е n е - с a r r y i n g rЬinationsin еaсh and еvеry offvould hаvе markеdly spееdеd thе f thеir novеl gеnеtiсsсould сonrprеviously ownеd Ьy thеir nonnеnt wеll еvidеnсеd Ьy rRNA )gy. ; of uniсеilularеukаryotеs rесord atеs -1 Ьillion yеars ago (Sсhopf organismsdatе from thе so-сallеd ) million yеars ago. To еvolvе to n thе half a billion yеаrs Ьеtwееn Сambrian. And еvolution did inl multiсеllular sеаwееdsЬy -850

()rgаtlislтliсЕuolutiсп аnd Rаdiаtiсln bеforе tbе Саmbriап

Thrее mеmЬеrsof thе latеst PrесarnЬriаnЕdiaсaran F.аunatlf soft-Ьodiеd animаls,prеsеrvеdаs imprints ir-rsirndysеdimеntaryroсks of thе -560 millionyеar-oldPound Quаrtzitеof South Australia.(t) Тribrасhidium,a triradia[ly symmеtriсalfсlssilpсlssiЬlyrеlatеdtсl сor:lls;(B| Dickiпsсlпla,аn сlvaгееvidеntly wormlikе animal;(С) Spriggiпа,a sсgmеntсdanimal having a disтinсtivе thiсkеnеdhеad shiеld (Иppеrright). (Barsfor sсalеrсprсsсnt1 сm.)

Lndprimitivе protozoans' prеsеnt . e t a | . 1 9 7 7 1P о r t е r е t a l . 2 0 0 3 ) , )pmеntof soft-Ьodiеdmultiсеllеd rring this pеriod lifе also suffеrеd .n all thе largеst-сеllеdaсritarсhs i m а l s d е v е I о p е ds h е l I yp r o t е с t i v е tdvanсеthat marks thе Ьеginning anеrozoiсеon' and animal divеry nеw major typеs first аppеarеd.

;rеatradiation of lifе during thе thе timе of Darwin, its сausе rеols of thought сompеtе. Physiсal to major сhangеs in еarth's еnvinowЬall еarth,'' pеrhaps сouplеd In сontrаst,lifе sсiеntists (Ьiolols intrinsiсto lifе itsеlf (thе onsеt vеlopmеnt,suсh as thе ЬioсhеmiГfеrеntiation) thаt еnaЬlеd lifе to

Small skеlеtalfossils(Сbапсеlloriа)сlf thе typс that mark thе Ьеginningof thе PhanеrozoiсЕon of gеtllogiсаltimе, disstllvеdtlut сlf thе Еаrly СаmЬrian (-540 million-yеar-old)Ajaх Limеstсlnеоf South Arrstrаliа.Thе intriсаtеlysсulpturеd frаgmеntsаrе thoughttо hаvе {it tсlgеthеrttr mаkе up thе Ьody armor of a sluglikеanimаl. (Bаr for sсаlеrеprеsеnts1 mm.)

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Оrgеl .With еvolvе to grеatеr сomplехity. nеw еvidеnсе and nеw idеas Ьеing addеd at a rapid сlip' this is onе of thе most volatilе and сontrovеrsial aгеas of еvo. lutionary biology (Сamеron 2004)' A firm answеr to this hotly dеЬatеd longstanding proЬlеm may soon Ье at hand, vеry likеly Ьasеd on a mеrging of thе еvidеnсеof molесular biology and thе known fossil rесord (Valеntinе 2004I. в|BLIoGRAPHY .Wang, Bеkkеr,A., LI. D. Holland, P.-L. D. RumЬlеIII,H. J. Stеin,J. L. Нannah, L. L. Сoеtzее,and N. J. Bеukеs.2004.Datingthе risеof atmosphеriс oхygеn. Nаtиrе427: 1I7_I2.0. Bloеsеr,B.,J. W. Sсhopf,R. J. Horodyski,and !И.J. Brееd..l977. Chitinozoans from thе Latе PrесamЬrianСhuar Group of thе Grand Сanyon.Sсieпсе195 676-679. Buttеrfiеld, N.J.' A. H. Knoll, and K. Swеtt.1990.^ Ьangiophytе rеd algafrom thе Protеrozoiсof arсtiсСanada.Sсiепсе250:.1О4-1О7. Сamеron,R. A. 2004.Huntingfor origins.Sсieпсe30.5:613-614. Hofmаnn,H.J., K. Grеy,A. H. Hiсkman' and R. I. Thorpе."|999.origin of 3.4.5 .Wеstеrn Gа сoniform stromatolitеsin !ИarrawoonaGrоup, Australiа. GеologiсаlSoсietуof АmеriсаBulletiп111:1256_1262. Portеr,s. М., R. Mеistеrfеld,and A. Н. Knoll.200З.V:rsе-shареd miсrofossils from thе NеoprotеrozoiсСhuar Grоup, Grand Сanyon:A сlassifiсatiоn guidеdЬy modеrntеstatеamоеЬae. 77:409_429. .|слrпаlof Pаlеontolсlgу Sсhopf'I.w.1992. Еvolutionof thе ProtеrozoiсЬiosphеrе: Bеnсhmаrks, tеmpo,and modе.In J. W. Sсhopfаnd С. Klеin, еds.,ThеProterrlzсliс Biosphеrе: А М ultidisсipliпаrуStudу,583_600.Nеw Yсlrk:СamЬridgеUnivегsityPrеss. 1993.Мiсrofossilsof thе Еarly ArсhеanApех сhеrt:Nеw еvidеnсеof thе antiquityo| |ife.Sciепсе26О:64О_646, 1994.Disparatеratеs'diffеringfatеs:Thе rulеsof еvolutionсhangеdfrom thе PrесamЬrianto thе Phanеrozoiс.Proсееdiпgsof thе NаtiсlпаlАсаdеmуof SсiепcеsUSА 9,l':67З5_6742. 1999, Сrаdlе of Lifе: Thе Disсouеrуof Еаrth's ЕаrliеstFоssl/s.Prinсеton, NJ: PrinсеtonUnivеrsitуPrеss. Valеntinе,J. \)и.2004. Оп thе Оrigin of Phуla. Chiсago:Univеrsityof СhiсagoPrеss.

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orgеl, LеsliеE'. (t927-2007) Lеsliе Еlеazеr Orgеl, a lеading origin-оf-lifеsсiеntist'spеnt most of his сarееr at thе Salk Institutе for Biologiсal Studiеs in San Diеgo, hеading thе Сhеmiсаl Еvolutiоn LaЬoratory. Born in Еngland, hе еarnеd his undеrgraduatе dеgrее and doсtoratе in сhеmistry from Oxford Univеrsity. Latеr, at СamЬridgе Uni. vеrsity hе hеlpеd dеvеlop a thеory of сhеmiсal Ьonding in mеtals, ligand fiеld thеory. |o 1964 orgеl movеd to thе Salk Institutе, whеrе hе dеvotеd many yеars of rеsеarсh to еluсidating thе сhеmiсаl proсеssеs that lеd to thе еmеrgеnсе of lifе on thе primordial еarth. In addition to many prizеs аnd awards' Orgеl was еlесtеd a fеllow of thе Royal Soсiеty iл 1962 and in thе Unitеd Statеs,tn 1990, а mеmЬеr of thе National Aсadеmy of Sсiеnсеs. In thе 1960s Orgеl suggеstеdthаt vеry еarly in thе еvolution of lifе molесulеs of RNA сould havе funсtionеd Ьoth as gеnеtiсmatеrial and аs сatalysts.

This idеa, latеr саll proposеd also Ьy thс . Amеriсan miсr
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mеntаl сhiсkеn.and-еg without рrotеin еnzym thе idеa in mind of R} work in thе 1960s and сhains on tеmplatеsof еnzymеs. Нowеvеr, fur rеpliсation-сopying tl without an еnzymе. Although orgеl lvаs sis arrd Ьеliеvеd that th lutiсln of iifе, hе Ьесaп this thеory to thе vеry h е с a m е t o r е a l i z еt h е s е q u е n с ес a p a Ь l еo f с a of thе RNA-world сtlr Ьinеd with his сandid tiеs сlf prеЬiotiс сhеmr s i n l p l е r g е n е r i сm а t с r dially. Among thе саnl m o l е с u | е sd i f [ е r с n tf r r sеarсЬеd for rеpliсatin positivеly and nеgativ othеr. Throughout his сarее nautiсs and Spaсе Аdrт planеts. In thе еaгly 19 сhromattlgraph аnd rnс Viking landеrs. Upon la сhесkеd samplеs of Мa nonе. Bесаusе of ехistln еts, this rеsult wаs surp nсlt all of thеm) as irrdi solar ultraviolеt rаdiatr lеaguе Franсis Сriсk, C аЬout thе possiЬility of ttrrе of sееdsor sееdsеvt еarth Was sееdеdintеnt tion that sеnt an unmаП ria tO mаny planеts in t}

Оrgеl еnсе аnd nеW idеas Ьеing addеd е and сontrovеrsial arеas of еvo:lswеr to this hotly dеЬatеd longlikеly Ьasеd on a mеrging of thе n fossil rесord (Valеntinе 2004).

Ьlе III, H. J. Stеin,J. L. Нannаh, rg thе risе of atmosphеriс oхygеn. /. Brееd. 1977. Сhitinozoans J. ,l'95: thе Grand Сanyon. Sсiепсе 0. A Ьangiophytе rеd alga from thе 04-107. с e 3 0 5 :6 7 з _ 6 | 4 . . I. Thorpe. 1999. Origin of 3.45 .Wеstеrn Australia. iroup' 1256-1262_. )03. Vаsе-shаpеdmiсrofossils from t n y o n :A с l а s s i f i с a r i оgn, u i d е dЬ y .iogу 77: 409_429. Ьiosphеrе:Bеnсhmаrks,tеmpo, and te PrсltеrоzoiсBiosphеrе: A k: СamЬridgеUnivеrsity Prеss. Apех сhеrt: Nеw еvidеnсе of thе е rulеs of еvolution сhangеd {rom iiпgs of thе Nаtklпаl Аcаdеmу of :,аr! h's Еаrliсst Fоssl/s.Prinсеton' hiсago:Univеrsityof Сhiсago Prеss.

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sсiеntist,spеnt most of his сarееr San Diеgo' hеading thе Сhеmiсal еarnеd his undеrgraduatе dеgrее vеrsity.Latеr, at Сambridgе Unial Ьonding in mеtals' ligand fiеld ilstitutе' whеrе hе dеvotеd many Ll proсеssеsthat lеd to thе еmеrition to mаny prizеs and awards' ,сiety in 1962 and in thе Unitеd сadеmy of Sсiеnсеs. Lrly in thе еvolution of lifе molеgеnеtiсmatеrial and as сatalysts.

This idеa, latеr сallеd thе RNA-world hypothеsis' was indеpеndеntly proposеd also Ьy thе сodisсovеrеr of DNA struсturе Franсis Сriсk and thе Amеriсan miсroЬiologist Сarl R. \й/oеsе. Thе RNA-world thеory gainеd сrеdеnсе in thе еarly 1980s whеn riЬozymеs' RNA molесulеs that showеd сatalytiс aсtivitiеs,wеrе disсovегеdin prеsеnt-dayсеlls. Thе сlaim tlrat RNA molесulеs Wеrе thе solе playеrs in thе origin of lifе, sеrving as prесursorsto DNA and protеins, сould potеntiаlly solvе a fundamеntal сhiсkеn-and-еggpuzzlе: how сould thе gеnеtiсmolесulе, DNA, еvolvе without protеin еnzymеs'and how сould protеins еvolvе without DNA? With thе idеa in mind of RNA :rs a solе playеr with no nееd for protеins' Orgеl's work in thе 1960s аrrd 1970s dеmonstratеd thе synthеsis of сomplеmеntary сhains on tеmplatеsof short sеquеnсеsof RNA without сatalysis Ьy protеin еnzymеs. Howеvеr, furthеr rеsеаrсh madе Orgеl rea|izethat a сomplеtе sеlfrеpliсation-сopying thе сopiеs of thе original sеquеnсеs-was impossiЬlе without an еnZymе. Although Orgеl was instrumеntal in advanсing thе RNA.world hypothеsis and Ьеliеvеd that thе RNA wtlrld did play a сruсial rolе in thе еarly еvolution of lifе, hе Ьесamе or-rеof thе most sеvеrе сritiсs of thе appliсation of this thеory to thе vеry origin of lifе. on thе Ьasis of numеrous ехpеrimеnts hе сamе tсl rеalizе thе improЬaЬility of thе prеЬiotiс synthеsis of an RNA sеquеnсесapаЬlе of сatаlyzing its own rеpliсation-thе сеntral rеquirеmеnt of thе RNA-world сonсеpt. Orgеl's outstanding сhеmiсal ехpеftisе' сomЬinеd with his сarrdid and сritiсal еvaluation сlf thе strеngths and diffiсul. tiеs of prеЬiotiс сhеmistry, lеd hirn to an opеn-mindеd sеarсh aftеr muсh simplеr gеnеtiс matеrials that сould havе Ьееn еasily synthеsizеd primordially. Among thе сandidatеs for a prе-RNA world, orgеl studiеd sеvеral molесulеs diffеrеnt from Ьut still similar in struсturе to RNA. Hе also sеarсhеd for rеpliсating polyпrers unrеlatеd to nuсlеiс aсids' for ехamplе' positivеly and nеgаtivеly сhargеd аmino асids that would pair with еaсh othеr. Тhroughout his сarееr Orgеl was сlosеly assoсiatеdwith thе National Aеronautiсs and Spaсе Administration (NASA) and thе sеarсh for lifе on othеr planеts. In thе еarly 1970s hе Was part of thе tеam that dеsignеd thе gas сhronratograph anсl п1ass spесtromеtеr sеnt to Мars on Ьoard onе of thе Viking landеrs. Upon landing on Mars lл 1976, thе miniaturizеd instrumеnt сhесkеd samplеs of Мartian soil for traсеs of organiс molесulеs and found nсlnе.Bесaшsеof ехisting data rеlеvant to Мars and othеr solar-systеmplanеts, this rеsult was surprising and wаs intеrprеtеdЬy most sсiеntists(though not all of thеm) as indiсating an aсtivе dеstruсtion of organiсs on Mars Ьy solar ultraviolеt radiatiоn. Togеthеr with his friеnd and Salk Institutе сollеaguе Franсis Сriсk, orgеl raisеd in 197З a highly spесulativе hypothеsis aЬсlut thе possiЬility of direсtеd pапspеrmiа (pапspermiа is Grееk for miхturе of sееdsor sееdsеvеrywhеrе).Сriсk and Orgеl wondеrеd whеthеr lifе on еarth was sееdеdintеntionally Ьy a highly dеvеlopеd ехtratеrrеstrialсivilization thаt sеnt an unmannеd spaсеship loadеd with diffеrеnt spесiеsof Ьaсtеriа to many planеts in thе Milky \Wаy.

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origiп of Vcrtеbrаtеs Orgеl wаs thе first ttl аdmit thаt thе idеa of dirесtеd panspеrmia laсkеd any еmpiriсal еvidеnсе, аnd hе сеrtаir-rlyЬеliеvеd that thе еnrеrgеnсеof lifе on еarth was morе likеlу, Ьut hс thought that thе idеir should Ье еntеrtainеd Ьy origin-of-lifе rеsеarсhеrs,аt lеast сltr slееplеssnights. This Ьold spесulation was onе indiсаtion among rrrany of orgеl's htlnеst assеssmеntof thе еnormous diffiсultiеs faсеd Ьy thе origin-of-lifе fiеld. Hе сonсеdеd on manу oссasions that our undеrstanсlitlgсlf thе proЬlеm is still grеatly laсking. At thе samе timе hе was сonvinсеd thаt only pеrsistеntrеsеаrсhсould rеvеalthе dеtailеd path from a lifеlеssplanеt to thе first tlrgаnizеd living systеms. B|вLIoGRAP1{Y Orgеl,L. Е. |994.Thе сlrigillof lifс оn thееarth.SсiепtфсАmеriсап,(JсtoЬеr:5З_61. 1998.Тhс originof lifе-A rеviеwof fасtsanсlspесulаtions. Trепdsiп - 1 . tт . с BioсЬеmiсаlSсiепсеs2З: 19 1_495.

origin of vеrtеbratеs Thе origin of vеrtеЬratеs'morе thаn of any othеr anirтaI group' hаs Ьееn thе subjесt of vigorous historiсirl dеЬаtе,and this сOntinuеsto Ье thе сilsе.Howеvеr' a rеnаissanсе in intеgrativе organismiс Ьioiogy hаs rеinvigoratеd dеbatе' sparkеd Ьy fundal.nеntalnеw insights into thе origin of vеrtеЬratе сharaсtеristiсsfrсlm within thе fiеld of dеvеloprтеntalgеnеtiсs.In turn, this has stimulatеd anatomists and palеontсlltlgiststo tеst thе hypothеsеs that havе еmеrgеd from within this fiеld. Muсh of this work has rеvеаlеd how сhеrishеd assumptions arе unfoundеd and has providеd nеW pеrspесtivеson thе origin сlf thе majсlr аninral group tO whiсh wе сlursеlvеsЬеlong. Thе starting poirrt of thе mtldсrn pеrsресtivсon thе origin of vеrtеЬratеsis thе nеw.hеad hypothеsis.In еssеnсеit сlЬsеrvеsthat although thе diffеrеnсеs Ьеtwееn vеrtеЬratеsand thеir nеarеstinvеrtеЬrаtеrеlativеsarе vast' virtually all thеsе сharaсtеrsoWе thеir origin ttl just a fеw еrrrЬryologiсalnovеltiеsand arе mainly assoсiаtеdwitlr thе hеаd. ]n thе main, thеsе :rrе thе nеural сrеst and nеurоgеniсplaсodеs (spесializеdrеgions of еmЬryoniс есttldегm),Ьoth of whiсh form spесiаlizеdsеnstlryOгЕ]ans'whilе nеural сrеst сеlls also diffеrеntiatе into skеlеtal, сonnесtivе' and musсlе tissuе. Thе hypothеsis was аlso framеd within an еvolutitlnary sсеnario, drawing upon еvidеnсе from сom. parativе anаtomy, dеvеlopmеntalЬitllogy,and palесlntologyand arguing that thе еstaЬlishmеntof thе vеrtеЬratеЬody plan was assoсiatеdwith а trеnd of inсrеasingly aсtivе food aсquisition, frсlm passivе filtеr fееding to prеdation. Thе nеw-hеad hypсlthеsis hirs prtlvеd ехtrепrеly influеntial' to thе ехtеnt that most of thе rеsеarсhduring thе еnsuing dесadеshаs Ьееn aimеd at rеstingits assumptionsand postulatеsin fiеlds аs divеrsеas rnсllесulаrdеvеlopmеntalgеnеtiсs' molесulаr:phyl
с o h е r е n td i s с i p l r n еw I l fгсlmwithin dеvеl.'pm p o г h е s i sh а v е е m е r g с . F i r s t 't h е h у p o r h е s s е n t i a | | yt h е y e г е i n rе r This wаs асhiеvеd Ьy Ьratе rеlativе of thе vt .| h с a d r t f v е r t е Ь г l t е sТ mals and аrе ехprеssе thе ехprеssion of tlthе ing thе еаrly еmЬryo, с i n a | |а n i m e l s ,v е г t е Ь prеssеd within thе hеa Ь r а i n . Т h е r е s u l t so f t l r of thе lanсеlеt Ьody is n е w h е а d ' г h с l u g hа v с r сhаssis rathеr than а r'v Т h е d i s с o v е r i е si n t h movlng on Wе musttnf r e l с r е s ta n d е p i d е г m tivеs of thе vеrtеЬratеs сеll populations,thos prеssion and somе of rudimеntary sеnsе org n е ur o g е n i сp | а с o d е sn' opmеnt. Thus altlroug s n l а | | е ri.г а p p е a r sг h a с o d е si n а l | Ь u t l 1 а n l е p o s s е s st h е s еf u n d а n l е a t i v с s o f v е r t е Ь r e t е sJ.l

сoМPARAт|VЕ (

Сomparisons of vеrtеЬ ologiсal lеvеls сlеariy п than thеir spinеlеssrеla thе gеnomе, thе liЬrarl еrеd thаt vеrtеЬr,ttеsp. animal, Ьut that quality Ьеr vаriеs within invеrt tеr, mеaning that thеy сhromosсlmе, and all a Ьratеs, r'vhiсh possеss . found in invеrtеЬrаtсs o f v е r г е Ь r а t е сs o i n с i d с sеrvation givеrr thе fun сlgy. Нowеvеr, furthеr

Origiп сlf Vеrtebrаtes 789 r of dirесtеd parrspеrmiа laсkеd iеvеd that thе еmеrgеnсе of lifе rt fhе idеirshould Ье еntеrtirinеd plеss rrights.Tlris Ьold spесulalrgеl'shonеst :lssеSsmеntof thе Iifе fiеld. Hе ссlnсеdеdon l]lаny l b l е m i s s t i l l g r е a t l yl a с k i n g . A t .sistеntrеsе.rrсhсould rеvеal thе t сlrganizесlliving sr'stеms.

ciеltti|lсАпrcriсаn,OсtoЬеr:.5З_61. s and spесulаtioпs. Trепds ill -1.F.

lthегarrirrrаigr()ttp'hаs Ьееr-r thе ; сontinuеsto Ье thе сasе. HOwс Ьiologv hаs rеinr,igorаtеddеs inttl tlrе огigin оf vеrtсЬrаtе opmеntаl gеnеtiсs.In turn, this ists to tеst thе h1,pсlthеsеsthаt of this rvork hаs rеvеalес]how r s p r t l v i d е dn е W p е r s p е с t i v е sс l n h w е o u r s е l v е sЬ е l o n g . vе on thе origin oi vеrtеЬratеsis lеs thаt аlthough thе diffеrеnсеs Ьгatеrеlativеsarе v.lst' virtttаllу fеw еmЬгyolсlgiсllnovеltiеs and main, thеsеarе thе nеural сrеst of еmЬrуolriсесttlсlс.гm)' Ьotlr of : nеurаl сrеst сеlls аlso diffеrеnissuе. Thе hypothеsis wаs also wiпg upon еvidеnсс from сotnd palеontologyarrd arguing that t was asstlсiаtеdц.ith а trеnd Of ssivеfiItегfЪеdirrgt
Eт|сs зd with thе rolе сrfцеnе ехpгеso | o g y l.t t I i dn t ' r с v е n е х i s t e s а

сohеrеnt disсiplinе wlrеn thе rrеrд.-hеad h).pothеsiswаs forrnulаtеd, Llut it is from within dеvеlopmеntаl gеnеtiсs thаt thе grеatеst сhallеngеs to thе hypothеsislravе еmегgеd. First' thе hypсlthеsisthat vеrtеЬгatеspossеssеdа litеral nеw hеad' that еssеntially tЬеy arе invеrtеЬratеswith a hеасl addеd tO thе frсrnt,was tеstеd. Tlris was aсhiеvес]lly ехaп.rinineirr lanсеlеts (prеsr-tn-rеd thе сlosеst itrvеrtе. Ьratе rеlаtivе of thе vеrtеЬratеs)thе pattеrns of е-хprеssiorrof gеnеs in thе hеad оf vеrtеЬrаtеs.Thеsе gеnеs,known аs Flox gеl'еs' arе found in irll аninlаIs and arе ехprеssеdvег1,еаrl1'irr dеr,еloprтеnt,dirесting аnd rеgulаting thе ехprеssiсlnof othеr gеnеs.Thus thеy hаvе a funс]amеntalrolе iп сlrgаntz. ing thе еаrly еmЬгyo, еspесially its hеad-tаil aхis. Although thеy arе prеsеnt in аll anir-rrals' vеrtеЬratеslravе tlrе most Hox gеr-rеs of аlI, апd somе аrе еХ. prеssеdwithin thе hеаd-tLrilaхis of thе еmЬryo only at thе lеvеl of thе hindЬrain. Thе rеsults of thе ехpеrimеntsrеvеalеdthat a portion of thе front еnd of thе lanсеlеt Ьody is сt1uivalеrrtt() thе \rеrtеЬratеhindЬrz-rin'and thus tlrе nеw hеad, though а vеrtеtrrаtеnovеlty, was a dеvеlopmеntoi аn invеrtеЬratе сlrassisrathеr than а wholl1.nеw domair-r. Thе disсovеriеsin this nеw fiеlс{arе too many to rесoulrt hеrе, Ьr-rtЬеfсlrе moving on Wе rтlustmakе mеntion of thе disсovеry of a possiЬ1еnasсеntnеurill сrеst аr-rdеpidеrmal plасodеs in thе tuniсаtеs,invеrtеЬrаtесhordatе rеlа_ tivеsof thе vеrtеЬratеs.Although malry inr,еrtеЬratеgror.rpspossеssпligrаtory сеll populations, thtlsе tlf turriсatеsеxhiЬit thе sarnе pattеrns of gеnе еx. prеssion atrd sсlllе of thе fatеs of nешrаl сrеst сеlls. Tuniсatеs also possеss rudimеrrtary sеnsе organs that dеvеlop frсlm есttrdеrmal thiсkеnirrgs,likе nеurogеniсplaсoсlеs,and ехhiЬit a сommon suitе of gеnеsduring thеiг dеvеlOpmеnt. Thus although tlrе rеpеrtoirе сlf епrЬryologiсaI dегivаtivеs is fаг smallеr, it appеars thаt tuгriсаtеsp()ssеssnецra|сrеst сеlls and еpidеrrnal plaсodеs in all Ьut nаmе. Thе quеstion rеmains, howеvеr' why tuniсatеs should possеss tlrеsе firndilrnеntаl еrтЬrl'сllogiсal nсlvеltiеslr,lrеrrlanсеlеts, сllrsеr rеlаtivеs of VеrtеЬratеs,do not. сoМPARAтIVЕ GENoM|сs Сomparisons of vеrtеЬratеsand inr,еrtеЬratеsаt thе аnаtomiсal and еmЬryologiсаl iеvеls сlеагly пrzrrkout vеrtеЬratеsаs in stltrrееssеIlсеmсlrесssеss аt lеаst twсl Hox сlustеrs, еасlr еquivаlеnt to tЬе onе found ilr iпvеrtеЬratеs.This simplе fеaturе rnight suggеstonly thаt tlrе origin of vеrtеЬratеsсoinсidеd with a dupliсation of thе Hox сlustег-no mеan сlЬsеrvati()ngivеn thе fundanrеr-rtal rolе plаyесl Ьу Нoх genеs сluring еnrЬryol_ ogy. Hсlwеvеr, furthеr сtlmрeratir.сsurvеl's of vеrсеЬratеirnd invеrtеЬrаtе

790

Оrigiп of Vertеbrаtеs gеnomеshаvе rеvеаlеdtlrat thе samе phеllomеllOnis еnсoЦntеrеdin ссruntlеss othеr gеnеsand gеnе fаmiliеs.This hаs lеd tсl thе сonсlusi'llokuпlпillgiа,from tЬе Сhеngiiаng fossil dеposit of South Сhina. SkеlеtonizingvеrtеЬratеswеrе prеsеntЬy thе [,atе Сar.nЬriагr(501 million 1.еаrsаgсl)at thе vеry ii]tеst'i1sеvidеnсеdЬy thе prеsеnсе of ссlnodсrnts.What is mсlrе' аll thеsе еаrly fossils аrе from roсks dеpositеd undеr nrarinесonditions' providing сompеllingеvidеnсеfсlr thе marinе origin of vеrtеЬratеs. Pаlеontolog1'providеs not only a timеsсalе for vеrtеЬratеorigin Ьut also insiglrt into thе sеqLlеnсеin rд'lriсhvеrtеЬratе-spесi{iс сhаraсtеrs wеrе aсquirеd, сonstrаining whеthеr or not vеrtеbratесharaсtеrsеvolvеd in сonсеrt or in a staggегеdfashion Ovеr 11protraсtеd еpisodе.Unfoгtunаtеly, thеrе irrе prесious fеw rеmains of urrеquivoсalprimitivе vеrtеЬratеsin thе fossil гесord, an artifасt of thеir lirсk of minеralizеd tissuеs.Nеvеrthеlеss,thе fossil rесord of vеrtеЬrzltеstnorе advar.rсеdrhan thе most primitivе living vеrtеЬrаtеsis suffiсiеntto rеvеal tlrat many сlraraсtеrsgеnеrally dееmеd vеrtеЬratеspесifiс wеrе aсtually aсquiгеd rnr"rсhlаtеr. anl()ngnow-еxtinсt linе:rgеsintеrmеdiatе Ьеtwееnthе living lаmprеvs and livirrg jawеd vеrtеЬrаtеs.ln fасt' our knowlеdgе of thеsе ехtinсt irrtеrmеdiаtеsis suffiсiеnttrl ехсludе tlrе possiЬility of a major anаtomiсal еvеnt to с
Knowlеdgе of thе еvo itivе vегtеЬratеshas аls< aсquisition drrlvе еarly laпсеlеts(filtег-fееding rr and jawеd vеrtеЬratеs funсtionaI anаlysеsсlf еr progrеssivе pаttеrn is a tinсt jawlеss vеrtеЬratеg с а t е d [ е е d е r s( s с а v е l l g е

Ьеen dеposit fееdеrs,ma Althоtrgh thе ftlssil r downplayеd hеrе, thеrе fiеd' iпсluding addiriоrrа posit (Hаikoиеllа, Yuпп (Pikаiа' р"ft 196a7,l.s/' Nс е с h i n o d е r m -ilk е o r g . r n i s loplrorans. Thе intегprеt trovеrsial, but somе sрес almost еvеry possiЬlе kir and thе сlrordatеsuЬphi, dеrstanding in intеrprеt phyla (есhinodеrms,hеt of thе most importаnt сl n o t d е r i v е dс h а r а с t е r i s t MoLЕсULAR PHY

Traditional pеrсеptions( rесognizе hеп-riсhordatе phylogеnеtiс analysis of l and hеmiсhorсlatеsarе е Ambulaсrаria, to thе ехс Нistoriсally thе rеlatr and еithеr tuniсаtеsor la vеrtеЬratеs.Thе modеrп vегtеЬratеs,Ьut this hаs t сatеs appеar to possеssе of vеrtеЬratеs,аs wеll as . fatеs sееn in nеural сrеst H a v е t l r е s ес h а г а с t е r i сatеs, or rvеrе tЬеy lost analysеs сlf largе molесu саtеs Js тhесlo'еsr liring pliсations of thеsе disсov and nеurogеniс plaсodеs Ьratе еvolution. Сlеаrly t Ьryologiсal fatеs among

origiп of Vеrtebrаtеs 79-I nеnonis еnсountеrеdin сountlеss l thе сonсlusionthat thе origin of gеnеdupliсation' possiЬly at thе tеsis,that thе еntirе gеnomе Was l havе providеd a vаst numЬеr of ге availaЬlеfor сo-option to nеw ,еrtеЬratеs.In faсt, it has Ьееn ar-sсalеgеnеdupliсation сould proсllvingin сonсеrt' suсh as at thе l vеrtеЬratеs.\Ие now know that еrtеЬratееvolution,sinсе gеnomе f jawеdvеrtеЬratеsand thе оrigin ] anatomy has Ьееn adaptеd at a at lеaston thе еvidеnсе эrtеЬratеs,

rnеtiсshas lеd dirесtly to rеnеwеd nеw hypоthеsеson thе origin of эns.This hаs Ьееn еspесially truе mаdе to сhasеthе origin of vеrtе. еr dееpеrinto gеologiсal history. t s , f o r е x а m p l е ,t h е r е а s s i g n m е n t ls, suсh as thе сonodonts, as wеll iс and sеrеndipitoussеarсhing of vidеnсеfor vеrtеbratеsехtеnding гs ago) on thе Ьаsis of a wеllmiпgiа, from thе Сhеngjiаng fos:tеbratеsWеrеprеsеntЬy thе Lаtе .y latеst,as еvidеnсеdby thе prеs: еarly fossils arе fгom roсks dе:ompеllingеvidеnсеfor tlrе marinе alе foг vеrtеЬratеorigin Ьut also ratе-spесifiссharaсtеrs wеrе aс: а t ес h а r а с t е r sе v o I v е di n с o n с е r t еpisodе.Unfortunаtеly, thеrе arе vе vеrtеЬrаtеsin thе fossil rесord, еs.Nеvеrthеlеss'thе fossil rесord lst primitivе living vеrtеЬratеs is rеrally dееrтеd vеrtеЬratе spесifiс 1ow-ехtinсtlinеagеs intеrmеdiatе :d vеrtеЬratеs. In faсt, our knowlеnt to ехсludе thе possiЬility of a е gеnomеdupliсation that сan Ье

Knowlеdgе of thе еvolutit>naryrеlаtionsl-rips of Ьotlr fossil аnd living primitivе vегtеЬrаtеshas also providеd a tеst of thе nеw-hеad sсеnаrio that food aсquisition drovе еarly vеrtеЬratееvolution. UndouЬtеdly thе living groups lаnсеlеts(filtеr-fееdinginvеrtеЬratеs),lаrrrprеys(parasitiсjawlеssvеrtеЬratеs), and jawеd vеrtеЬratеs (primitivеly prеdatoгs) Ьеаr this Out' but rigorous funсtional analysеsof ехtinсt jawlеss vеrtеЬratеshavе dеmonstгatеdthat this progrеssivеpattеrn is a gross ovеrsimplifiсation of асtual еvеnts. Sсlmе еxtinсt jawlеss vеrtеЬratеgroups likе thе сonodonts wеrе undouЬtеdly sophistiсatеd fееdеrs (sсavеngеrs/prеdators), Ьut most othеr groups appеar to havе Ьееn dеposit fееdеrs,making thеir living Ьy slurping mud. Although thе fossil rесord of thе пrost primitivе vеrtеЬratеs has bееn downplayеd hеrе, thеrе has Ьееn no shortagе of potеntiаl сandidatеs idеntifiеd, inсluding additional fossils from thе Lowеr СamЬrian Сhеngjiang dеposit (Hаikouеllа, Yuппапсlzooп)and thе Middlе СamЬriаn Burgеss Shаlе (Pikаiа, Nеktoсаris). Notе should also Ье mаdе of thе spесtrum of Ьizarrе есhinodеrm-likеorganisms rеfеrrеdto as thе сalсiсhordatеs'сarpoids, or stylophorans. Thе intеrprеtationof thеsе rеmains has long Ьееn ехtrеmеly сontrovеrsial,Ьut somе spесialistshavе pеrсеivеdthаt among thеsеorganisms liе almost еvеry possiЬlе kind of intеrmеdiatе bеtwееn thе dеutеrostomеphyla and thе сhordatе suЬphyla:tuniсatеs,lanсеlеts'and vеrtеЬratеs.Сhangеd undеrstanding in intеrprеtation of thе intеrrеlatiсlnshipsof thе dеutеrostomе phyla (есhinodеrms,hеmiсhordatеs,сhсlrdatеs)hаs, howеvеr' shown many of thе most important сharaсtеrs to Ье primitivе fеaturеs of dеutеrostomеs' not dеrivеd сharaсtеristiсsсlf tuniсatеs,lanсеlеts,and vеrtеЬratеs. MoLЕсULAR PHYLoGENЕт|сs Traditional pеrсеptions of thе intеrrеlationshipsof thе dеutеrostomеphyla rесоgnizе hеmiсhordatеsas thе сlosеst rеlаtivеs of thе сhordatеs. Howеver, phylogеnеtiсanalysis of molесular data has dеmonstrаtеdthat есhinсldеrms and hеmiсhordatеs arе еaсh othеrs' сl
792 Оrigin of Vеrtеbrаtеs vеrtеbratеs.Nеvеrthеlеss,thе divеrgеnсеof vеrtеЬratеsсlеarly сoinсidеs with an unfolding ехplosion in thе еmЬryоlogiсal potrntial of thе nеural сгеstand nеurogеniс plaсodеs. сoNсLUsIoNs our understanding of thе origin of vеrtеЬratеshas Ьeеn rеinvigoratеdin rесеnt yеars' largеly as а rеsult of a morе holistiс apprоaсh to undеrstаnding thе dеvеlopmеntaland еvolutionary еstaЬlishmеntof thе major animal Ьody plans. Togеthеr thеsе data providе for a morе protraсtеd еpisodе of еmЬryologiсal еvolution undеrpinning thе vеrtеЬratе origin of vеrtеbratеsrathеr than an еxplosivе radiation rеsulting from onе or two kеy innovations.Мany of thе fеaturеs dееmеd сhaгaсtеristiсаlly vеrtеЬratе arе now rесognizеd to havе a prеhistory among invеrtеЬratеs'inсluding thе nеura1сrеst and nеurogеniс plaсodеs. Thus in many of its dеtails thе nеw-hеad hypothеsis was wrong' Ьut thеsе arе just dеtails.Dеspitе disсovеriеsof еvеntsof gеnomе dupliсation, disсovеriеsof fossil vеrtеЬratеstеns of millions of yеars oldеr than thе oldеst prеviously known, and a fundamеntal ovеrhaul in our undеrstanding of thе invеrtеЬratе rеlativеs of thе vеrtеЬrаtеs' our pеrсеptions on thе origin of vеrtеЬratеsгеmain rootеd in thе nеural сrеst' nеurogеniсplaсodеs,and thе dеvеlopmеnt of a nеw hеad. BIBLIOGRAPHY Bеnton,М. J. 2005. VеrtеbrаtеPа!аеoпtologу. Oхford: B]aсkwеll. Сarrоll,S.B.' J.K. Grеniеr,and S' D. \WеathеrЬее. 2О01.FrrlmDNА ro Diuеrsitу: Мolесulаr Gепetiсsапd thе Еuolutiсlпof Aпimаl Desigп.Мaldеn, MA: BlaсkwеllSсiеnсе. Dеlsuс'F., H. Brinkmann,D. Сhourrоut'and H. Philippе.2006.Tuniсatеsand not сеphaloсhordatеs arе thе сlosеstlivingrеlativеsof vеrtеbrates. Nаturе4З9: 965-968. Donoghuе,Р. с.J.' A. Graham'and R. N. Kеlsh.2008.Thе originаnd еvolutionof thе nеuraiсrеst.BirlЕssays30: .530_541. Donoghr.rе' P. с.J., and М. A. Purnеll.2005. Gеnomеdupliсation,ехtinсtionand vеrtеbratееvolution.Тrеndsiп Есoklgу апd Еuolиtioп 20: 312_319. Oхfоrd: oхford UnivеrsityPrеss. Janviеr' P, 1996. Еаrlу Vеrtеbrafes. N{azеt.F.. and S. N{.Shimеld'2005.Мolесulаrеvidеnсеfrom asсidiansfсlrthе еvolutionaryorigin of vеrtеЬratесranial sеnsoryplaсodеs.lourпаl of ЕхpеrimепtаlZoologу, Pаrt B: Мolесulаr апd DеuеIсlpmепtаl Еuсllutitlп3О4B: з40-З46. Northсutt,R. G. 2005.Thе nеw hеadhypothеsis rеvisitеd. Joиrпаlof ЕхpеrimeпtаI Zoologу, Pаrt B: Мolесulаr апd DеuеklpmепtаlЕuolutiсlп304B:274-297. Purnеll,М. A. 2002. Fееdingin ехtinсtjawlеsshеtеrostraсan fishеsand tеsting sсеnаriosof еarly vеrtеЬrаtееvolution.Prсlсееdiпgs of the Roуаl Soсiеtуof Loпdoп,SеriеsB 269: 83_88. Swalla'B. J., аnd A. B. Smith.2008. Dесiphеringdеutеrostomе phylоgеny: Мolесular,morpholоgiсаlаnd palаеontologiсal pеrspесtivеS. PhiklsсlpbiсаI -Гrапsасtioпs oftbе RoуаISoсiеtуB: BiologiсаlSсiепсеs 363: 1557-1568. -PD.

osЬоrn, Hеnry Fair

Неnry Fairfiеld OsЬorn е a г l y t w е n t i е r h - с е n t u rly a patriсian attitudе towа s o с i е t y .H е w а s a с t i v еi n iсan \Иеst and in сеntral fiеld himsеlf. Hе dеsсriЬ dеvеlopmеnt of many rr с o n v i п с е d е v o I u t i o n i s tl basеd on parallеl еvolut h o w е v е r , h е w а s а W a r еt lution had lеd to thе qеv

hе popularizеd thе сonсс osЬorn was Ьorn in F rмas thе prеsidеnt of thе I New Jеrsеy (latеr Рrinсеtt Thе two Ьесаmе intеrеst ditions in thе !Иеst in 187 Drinkеr Сopе and Ьoth с ism Ьasеd on thе idеa o] major group. Aftеr studу land Balfour, OsЬorn tat lumЬia Univеrsity in Nеrд H е e I s o Ь u i l r u p l i n k sw i hе сrеatеd thе Dеpartmеr Osborn organizеd mаr in dеsсriЬing thе fossils l mals, aссеpting that thе Afriсa. Hе thought thаt sеparatе dеvеlopmеntfrо of Сopе on thе еvolurio ropе, Asiа апd North Ат еvolution. Не puЬlishеd figurе on pagе 794) and с old Stoпе Аgе (1916) wt Initially OsЬorn favort Copе's vision that еvolut later writings, though, ht invoking mystеrious forс dеtеrminеd dirесtions.At thе сorrеlation Ьеtwееn matiс сhangеs that havе t l o g i с a l t i m е . O s Ь o r n ' sv i innovativе adaptivе radiа pеriods of stеady pаrallе

С)sborn vеrtеbrаtеsсlеarly сoinсidеs with l potеrrtiаlof thе nеural сrеst and

rtеs has Ьееn rеinvigoratеd in re. 'listiс approaсh to undеrstanding ;hmеntof thе majoг aninral Ьody orе protraсtеdеpisodе of еmЬrylratе origin of vеrtеЬratеs rathеr |nеor two kеy innovаtions. Мany еrtеbratеarе now rесognizеd to uding thе nеural сrеst and nеuroils thе nеlv.hеad hypothеsis was ;сovеriеsof еvеrrtsof gеnomе duns of millions оf yеars oldеr thаn еntal ovеrhaul in or.rrundеrstand)ratеs!our pеrсеptionson thе oгial сrеst,nеurogеniсplaсodеs, and

)хford: Blaсkwеll. эе. 200l . Frtlm DNА to Diuersit1': vimаl Dеsigп, Мaldеrr, МA: . Philippе.2006' Tuniсatеs and nоt ivеs of vеrtеЬrates,Nаturе 439 r. 2008.

-Гhе origin аnd еvolution of

:nomеdupliсation,ехtinсtion аnс1 | Еutllutitltl 20: З12_З19. [ord UnivегsityPrеss. :vidеnсеfrom asсidiаnsfor thе sorу plасоdеs.lоurnа| of пd Dеz,еlсspttzеntаIЕt,olution З04B: s rеvisitеd.Jourпаl of Ехpеrimепtаl 'пtаl Еuоl иtiсlп З04B: 27 4-297 . lеtеrostгiсaI) fishеsаnd tеsrin8 'ееdings of the Roуаl Sсlсiеtу of 4 dеutеrostomеphуlogеny: ;iсal pеrspесtivеs.P b i losop h iса l tсаISсiеltсеs363: 1557_1568.

-P.D.

osЬoгn,Hеnry Fairfiеld(1s57_1935 ) Hеnry Fairfiеld osЬorn W21sonе of thе most influеntial palеontologists in еarly twеntiеth.сеnturyAmеriса. Не was indеpеndеntlywеalthy and adoptеd a patriсian attitudе toward his сollеaguеs.Ьasеd on his own position in high soсiеty.Не wаs aсtivе in promoting thе disсovеry of fossils Ьoth in thе Amеriсan \fеst and in сеntral Asiа, although in latеr lifе hе sеldom wеnt into thе fiеld himsеlf. Hе dеsсriЬеdпrany nеw fossil spесiеsand studiеd thе origin and dеvеlopmеnt of mаny importаnt groups of organisms. Although hе was а сonvinсеd еvolutionist, hе rеjесtеd Dаrwinism and movеd toward zr thеory Ьasеdon parallеl еvolution drivеn Ьy orthogеnеtiсtrеnds. At thе saпе timе' howеvег,hе was awarе that at сеrtain сruсial points in thе history of lifе еvolution had lеd to thе dеvеlopmеntof nеw forms with immеnsе potеntial' and hе popularizеd thе сonсеpt of аdаptiue rаdiаtion, osЬoгn was Ьortr in Fairfiеld, Сonnесtiсut, on August 8, 1857. Нis fathеr Was thе prеsidеntof thе lllinоis Сеntral Railrоаd. Hе studiеd аt thе Сollеgе of Nеw Jеrsеy (latеr Prinсеton Univеrsity), whеrе hе mеt William Bеrryman Sсott. Thе rwo Ьесamе intеrеstеdin palеontology and undеrtook fossil-hunting ехpе.Wеst ditions in thе in 1877 аnd 1878. Orr thе lattегoссаsion thеy mеt Еdward Drinkеr Copе аnd Ьoth сarrrеundеr tlrе spеll of his non-Darwinian еvolutionism Ьasеd on thе idеa of parallеl trеnds govеrning thе dеvеlopmеnt of еaсh majоr group. Aftеr studying in Britain with T. H. Нuxlеy and Franсis Mait. lаnd B:rlfour,OsЬorn taughс at Prinсеton unt'l l891, wlrеn hе movеd to Сolumbia Univеrsity in Nеw Yсlrk' whеrе hе foundеd thе Dеpartmеnt of Biology. Не also Ьuilt up links with thе Amеriсan Мusеum of Natural Historу, whеrе hе сrеаtеd tlrе Dеpaгtrrrеntof Vеrtеbratе Paiесlntology.osЬoгrr diеd in l9З5. osЬorn organizеd many ехpеditions thгoughout his сarееr and wаs aсtivе in dеsсriЬing thе fossils thеy disсovегеd.Hе woгkеd on thе origin of mammals, aссеpting thаlt thеy еvolvеd frolrr thе marrrпral-likеrеptilеs of South Afriсil. Hе thought that tlrе monotrеmеs (plaqvpusеsarrd есhidnas) wеrе a sеparatеdеvеlopmеntfrom a diffеrеntrеptiliаn stoсk. Hе сontinuеd thе work of Сopе on thе еvolution of mammalian tееth. His Аge of Маmmаls iп Еuropе, Аsiа апd |'Iorth Аrпеriса (1910) was a пr:rjorovеrviеw оf nrirпmalian еvolutiсln.Hе puЬlishеd monographs on thе giаnt ехtinсt titanothеrеs (sее figurе on page 794) and on tlrе fossil ProЬosсidеa (еlеphants).lHis Мeп of the Old Stoпе Аgе (19116)was an influеntial sufvеу of humаn palеontology. Initially osЬorn favorеd Copе's nеo-Lamаrсkism, and hе always rеtainеd Сopе's vision that еvolution Was сomposеd of mrrltiplеparallеl trеnds. In his latег writings, thor'rgh,hе favorеd аn orthogеnеtiсехplanation of thе trеnds, invoking mystеrious forсеs within tlrе organisrrrthat drovе vаriation in prеdеtеrminеddirесtions.At thе samе tiпlе' howеvеr, hе was aсtivе in ехploгing thе сorгеlation Ьеtwееn major evolutionary innovations and thе morе dгamatiс сhangеs that hаvе trarrsforпrеdthе еarth's сlimаtе аt kеy points in gеologiсal timе. OsЬorn's vision of еvolution was thus onе of rarе outЬursts of innovativе adaptivе radiation within nеwly formеd groups, followеd Ьy long pеriсldsof stеady ;larallеl dеvеlopmеntalnong thе Ьranсhеsthr"rsеstaЬlishеd.

79З

Оsborп

owеn, Riсhaгd (1l

Тlrе titanсlthеrе Was a lirrgе Inltrnmi1lthat гсrаmеdNorth Arrrеriса aЬout 30 million yеars ago. Hеrlrу Fаir1iеld OsЬсlгll rr.аsfilsсiI-ti-ttеd Ьу it, in part Ьесartsе Ьеing Ьig hе iеlt iт П,orthy tlf thе attеntiсln of а рlalеorltologistаs distinguishеd as hе, and in part Ьесаtlsе of thе Ьizarrе fсlrms that tЬеir nosеs toоk, еасh spесiеs oddеr thаn thе onе Ьеiorе. Tоdаy wе arе inсlinеd tсl think that thе nosеs arе thе produсt сlf sехual sеlесtion, Ьut OsЬсlrn saw thеm as еvidеnсе оf а kind of ..orthogеnеsis',' momеntum' in еvolutitln, whiсh tаkеs organisms to adaptivе hеights and thеn ovеr from thе usсful to thе dysfurrсtionаl and aЬsr-rrd.Sее

osЬоrn 1929ь.

BlвLloGRAPHY Bowlеr, P, I. 1996. l-iia's Splепrlid Drаmа. Сhiсagсl:Llпivеrsitуof Сhiсago Prеss. Grеgory' W. K' 1937' Biсlgrаphiсalmеmсliгof Hеnrу FirirfiеldosЬorn 1857-1 935. Nаtklпаl Асаdеm1, tf Sсicпсcs tlf thе Uпitсd Stаtеsrlf Аmеriса Biogrаphiсаl М е m o i r s : 5 1 _ 11 9 . OsЬсlrn, tl. F. 1910. Тhс' Аgе of Маmmаls iп F'urtlpе, Аsiil апd North Amсriса, Nеw York: Thе Масrnillаrr (iornpаny. |9|6. Меп of thс Оld Stoпе Аgе: Тhеir Епuirсlпtttt'llt, I'ifс' апd Аrt. Lorrdon: Gеorgе l3еll. 1929a. Frсlm thс Grссks ttl Dаrш,ilt: Thе [)cuсltlplltсltt tli tllе Еuolиtioп Idеа -F rl ur (',сtttu r ic s, Nец. Yoгk : Sсrillrlсr's. t ll rспryh Т u,с tl t.r' 1929Ь. Thс Titаlttltharcs t,l|.Апсiеllt |Й,l'сlпtittg' Dаkotа апd Nеbrаskа. lWashington,DС: L].S.C'tlvеrtltпеntl)rinting Offiсс. Rаngеr, R. 199] . Alt Аgclldа for Апtiqпitу: LIепrу Fаirfiсld Оsborп апdVеrtеbrаtе Раlесltltсllogуаt t|lс,,\mеriсап МLtsсtltтtof Nаturаl Нistorу, I890_1L).з5. Tusсaloosa:Univегsity of AlаЬarnа Prсss. Rusе, x4. 1996. Мсlпаd tll Мtlп: Thе (klпсеpt оf Рrog-rеssiп F'uolutioпаrу Biologу, -PIR СаmЬridgе, МA: Ьlаrr'ard Univсrsity Prеss.

Riсhard Owеn was an who foundеd thе Brit owеn Was thе sесond r. matriсulаtеd at ЕdinЬu 1827, at сhе agе сlf 22, retrlr' bеing rllildеаss F{untеrian Мusеlttl сlf сееdеd Сlift аs сOl1sегv w i s h е t |t ( ) r u г n t h е Н u history' Tlris provеd im Surgеons to Ьесomеthе at thе British Musеum, ral history musеum. TL British Мusеum (Natur thе puЬliс. During thе еzrrlуpar tronаЕ]еof oxЬridgе Ar pеrfесtеd thе funсtiona this woгk ,.:reЬls Меn work of :r dесadе latеr с owеn has Ьееn portray lution, whosе anti.Dar fight to еstaЬlishthе tru ovеr a pеriod of somе { owеn еxpliсitly :rnd rе Ьook' and lеrrеrs-his from сrеаtiсln tо spесiе approaсh from funсtion proaсh hе pеrfесtеdin l S h е l е t с l п( 1 8 4 8 ) . To dеmonstrаtе thе i thе dеvеlopпrеntof thе sсеndеntal аniltomy' in t and othегs, hzrсlЬееn m, at thе timе of Ьirth сon into an unyiеldirrgrvhо naturе of tlrе fеtаl skLr makirrg possiЬlе a сhanЕ ists only in plaсеntal ma mals and Ьirds, no sr parturition safеr, and y lеsсеd at thе timе оf Ьr what govеrns tlrе faсt t| of thе sаmе ntrпrЬеrof r

() tuеtl

Owеn, Riсhard (L804-1892)

oamеd North Amеriса :rЬout 30 ,vasfasсinatеd Ьy it, in pаrt Ьесausе '>ia pа|еontoltlgistas distinguishеd as ; that thсir nosеs toоk' еасh spесiеs Lсlinеdto tlrink thаt thе trosеsarе thе v thеm аs еvidеnсе оf a kind of vhiсh takеs oгganisms to adаptivе з dysfunсritlllаl аnd аЬsrrrd. Sее

riсаgсl:Ur.rivеrsity of Сhiсago Рrеss. f Hеnry l..aiгiiеldosЬоrn 1857-1935. :tеd Stiltеs of Апrcriса Bitlgrаphiсаl F'urоpе, Аsiа апd Nсlrth Аmеriса. ,:irЕпuirоnпtспt, Lifе, апd Аrt, Thе Dеuеklpmепt()f thс Еuolutioп ldеа lгk: SсгiЬnеr's. Wуomiпg, Dаktltа апd Nеbrаskа. ing offiсе. Iепrу Fаirfiсld osborп апd Vеrtеbrаtе f NаtиrаI llistor\', 1890-I9з5, оf Рrоgrr:ssiп Еuolutitlпаrl' Biс-lklgу.

-PJ.B.

Riсhard Owеn was an Еnglish сon-rpаrаtivеanаtonrist and palесrnttlltlgist who foundеd thе British Мusеum (Natural Histсlry). Born in Lanсаstеr, owеn was thе sесond of siх сhildrеn and thе youngеr of twсl s()l1s. In 1824 hе mirtriсulatеdаt ЕdinЬr-rrglrUrrivегsity Ьut stayесlOnly aЬollt hаlf а vеаr. hr |827, at'thе :rgеof 22, Оwen stаrtесlon his lifеlong сarееr as a musеutl.tсuratсlr, Ьеing madе assistаnt сurаtor to \Иilliam Сlift (1775-1 849) at thе Huntеrian Мusеum of thе Royal С
7L).5

796

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pеd thе vеrtеЬratе thеory of thе hе rеstof thе skеlеton, should Ье Гhе Ьasiс Ьuilсling Ьloсk of the :hеskеlеttlnwas a sеriеs of idеal hе rеlativеly simplе skеlеton of ion of virtually undiffеrеntiatеd f i g u r е )Т. h е m е l n i n g o f a n o r g a n rom its plaсе in thе arсhitесtural n its homologiсal rеlations to thе 'll vеrtеЬrаtе fеtusеs Ьесausе thе a r a г ес е p h а l i сv е г t е Ь r а е . г е dt h е с v i d с n с еf o г t h е е x i s t е n с е ltions to an aЬstrасt plan-from lnсе Wаs to Ье rесognizеd not so lсiеsЬut in thеir сommon ground Ьy natural mеans' not lry miraсl u t i t l u s ,s t l m е w o u l . l s а y с r y p t i с , r ехamplе, in ()п thе Nаture of rg his Angliсan Palеyitе patrons hе еnormouslyrеsеntеdit whеn (1809-1882)w , ith whom owеn s a сrе:rtionist. -tеsе.,naturalmеans'' wеrе. N7ith :d сompany.To owеn natural sеI spесiеs,nсlt tЬеir origin. Hе Ьеs of orgаniс unfоlding, drivеn Ьy эrnаiforсеs suсh as natural sеlесidеd Owеn with a visua|izing aid п Pаrthепogепеsis,сlr thе Sllссеs. .romа Siпglе ouиm (1849) hе dе. gеnеrations in thе rеproduсtivе ukеworms.Сharaсtеristiсof suсh nеrationsсan diffеr in form from еvеn gеnеra'familiеs, :rnd ordеrs ar сirсumstanсеsthе сyсlе would go on rеprodrrсing.In this way iginatе. rigins was, Ьy and largе, inсidеn. l musеumman whosе mаin amЬiгigin of spесiеsЬut еstaЬlishing a y. Thе issuеof еvolution was suЬ.rgagеnda.To a signiЁсant еxtеnt luЬjесtmattеr, and his thеtlrеtiсal lation.Thе traditionаl prеoссupal Darwin has hindеrеd a Ьalanсеd rplishmеnts.

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Riсhaгd Owеn argr-rеdth:rt al] vегtсЬгlltсs aге adaptivе mildifiсаtions of a Ьasiс arсhеtypе. l]volutionists likе Сhаrlеs Darwir.r assumсd that thе arсhеtypе rеprеsеntеd аn anсеst()I.Owеn pгoЬirЬlу did too, Ьut hе kеpt opеn thе option thаt it wаs Inorе 11lliс]е:rlrеprеsеntаtiсln.(FrtlrrrOrvеrl 1849a.)

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Ошeп BIBLIOGRAPHY -Гhе Dеsmond, A. 1989. Politiсs of Еuсllutiсlп: Мorphoklgу, Меdiсiltc, апd Rеfrtm iп Rаdiсаl Loпdоп. Сhiсagо: Univеrsity of Сhiсаgо Prеss. Owеn, R. \832. Меmoir oп tbе Pеаrlу Nаutilus (Nаutiltts Pсlmpilius, I-iпп.) шith Illustrаtioпs of lts Ехtеrпаl апd lпtеrпаl Struсturе' Londоn:.W. Wood. 7848. Оп thе Аrсbеtуpе апd Hсlmoklgiеs of thе Vеrtеbrаtе Skсlсtoll. London: Riсhard and John Е. Taylor. 1849a. Оп tbе Nаturе of Limbs. Londot.t:John Vаn Voorst. 1849Ь. Оп Pаrthепogепеsis, or thе SuссеssiuеProduсtitlп of Prсlсrсаtiпt Iпdiuiduаls from а Siпglе Оuum. London: John Van Vоorst. 1894. Thе Lifе of Richаrd Ошеп.2 vols. Lсlndon:.|ohnМurrаy. 2ОО7. Оп thе Nаturе of Limbs: А Disссlursе.Nеw еd. R. Amundsolr, еd. Chiсago: Univеrsity of Сhiсago Prеss. Riсhards, Е' A quеstion of propеrty rights: Riсhaгd owеn's еvolr.rtionisn.r rеаssеssсd. British Jourпаl for thе Historу of Sсicпсе 2О: 129_77|. Rupkе, N. A. 1994. Richаrd oшсz. Nеw Havеn, СT: Yalс Ulrivеrsity Prеss.Rеvisеd еd., Сhiсago: Univеrsity of Сhiсаgo Prеss,2009. Sloаn' P. R., ed. 1992. Riсhаrd Ошeп: Thе Huпtеriап Lесturеs itl Сompilr.ltiuе Апаfulmу, Мау-.|uпе, l8.37. Сhiсago: Ur-rivеrsity of Сhiсаgo Prсss.

-}J.А.R.

Palеy,William (|743

Arсhdеaсon \William Palе; еrs Of thе middlе-of-thе-r of Еngland. Hе was not a amplе' a sеnsе of purpos that is possеssеdЬy only tl еmotion out of his works thе slavе tradе and in pri and joy of Gсld.sсrеati painfully from сanсеr of t Two of Palеy's Ьooks' Ь bridgе in thе yеars whеn С thеrе is his work on rеvеal and сommitment. Еuidепс argumеnts aЬout miraсlеs Ье a Сhristian' givеn thе tс thеy wеrе prеparеd to und miraсlеs rеquirе somеthin and thе word of Jеsus'sfol As a studеnt Darwin ас Bеаgle voyagе hе саmе un o / o g y ( 1 8 3 0 - 1 8 3 3 ) ,w h i с t Wondегs of thе world-tht ular сauses opеratingovеI this' and as his Ьеliеf rn n miraсlеs gеnеrally. Givеn o n r h е е x i s t е n с еo f m i r а с nеvеr Ьесamе an athеist.Т in thе 18З0s hе joinеd Ly and sinсе for this God law was on thе way to еvoluti Palеy's othеr irnportant Work on thе intеllесtuall opеning aЬout finding a м Р a I е у а r g u е d f с l гt h е е х i s t tеlеsсopе,and sinсе thе tе

Iоrphr lIоgу, Ме d iс iпе' апd Rеform Сhiсаgo Prсss. (Nаutilus Poпtpilius, I'iпп.) tuith .!7. Wсlсld. "uсturе.Londоn: as of thе VеrtеbrаtеSkclеtoп. rr:John Van Voсlrst. . с s s i u сP п ' d ц с Ii , , t t ,l I I ' r l ' с y g 4 7 j n g ohn Varr Voоrst. ;. London: |ohn Мurray. lиrse.Nеu. еd. R. Amundsсln, еd. аrd orvеn's сvoltrtionismrеassеssеd. ):129-171. r, СT: Yаlе Univеrsitу Prеss.Rеvisеd 1009. !L'riаnI,ссtIr rсs iп Сt lm pl rа t i t'с :rsityсlf Сhiсаgсl Prсss.

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Palеy,William (t7 4з_Т8О5) .!Иilliam Palеy was onе of thе сlеarеst and most forсеful dеfеnd. Arсhdеaсon еrs of thе middlе-of-thе-roadkind of Сhristianity еpitomizеd Ьy thе Сhurсh of Еngland. Hе wаs not a vеry original thinker, Ьut hе had an еyе for an еxamplе' a Sеnsеof purposе, and an ovеrall skill at marshaling an argumеnt that is possеssеdЬy only thе vеry Ьеst tеxtЬook writеrs. Hе triеd hard to kееp еmotion out of his works, Ьut in puЬliс lifе hе was a dеdiсatеd opponеnt of thе slavе tradе and in privatе lifе was сomplеtеly сommittеd to thе wondеr and joy of God's сrеation' еvеn whеn at thе еnd of his lifе hе suffеrеd painfully from сanсеr of thе Ьladdеr. Two of Palеy's Ьooks' Ьoth standard rеading for an undеrgraduatе at СamЬгidgе in thе yеars whеn Сharlеs Darwin was a studеnt, сonсеrn us hеrе. First, thеrе is his work on rеvеalеd rеligion' that pаrt of rеligion that dеals with faith and сommitment. Еuidепсеs of Сhristiапitу Q794) has David Humе's skеptiсal argumеnts about miraсlеs in its sights. It makеs thе сasе that it is rеasonaЬlе to Ье a Сhristian' givеn thе tеstimony of Jеsus's disсiplеs and thе martyrdom that thеy wеrе prеparеd to undеrgo rathеr than dеny his divinity. Thе сlaim is that miraсlеs геquirе somеthing out of thе ordinary, an intеrvеntion Ьy a сrеator' and thе word of Jеsus's followеrs guarantееsthе vеraсity of thеir rеports. As a studеnt Darwin aссеptеd this argumеnt сomplеtеly. Howеvеr, on thе Beаglе voyagе hе саmе undеr thе influеnсе of Сharlеs Lуe||'sPriпсiplеs of Gеo/ogy (1830_183З), whiсh arguеd that no miraсlеs arе nееdеdto ехplain thе wondеrs of thе world-thе rnountains, thе sеas' thе lakеs, and morе. Just rеg. ular саusеs opеrating ovеr muсh timе arе еnough. Darwin was сonvinсеd Ьy this, and as his Ьеliеf in miraсlеs in this sphеrе dесlinеd, so did his bеliеf in miraсlеs gеnеrally. Givеn that his was a Сhristianity that dеpеndеd сruсially on thе ехistеnсе of mirасlеs, this mеant that his faith fadеd away. Darwin nеvеr Ьесamе an athеist. Toward thе еnd of his lifе hе Ьесamе an agnostiс. But in thе 1830s hе joinеd Lyеll in a form of dеism-God as unmovеd movеrand sinсе for this God laws arе thе grеatеstmark of his magnifiсеnсе,Darwin was on thе way to еvolution. Palеy'sothеr important pеrtinеntwork was his Nаturаl Тhеrllogу (1802)' a work on thе intеllесtual rеasonаЬlеnеssof Сhristianity, with its сеlеЬratеd opеning aЬout finding a watсh in a dеsеrt and infеrring a watсhmakеr. Thus Palеy arguеd for thе ехistеnсеof God, сlaiming thаt Ьесausеthе еyе is likе a tеlеsсopе,and sinсе thе tеlеsсopеhas a tеlеsсopеmakеr, so thе еyе must havе 799

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Реаrsoп Sсotаn еvе makеr, narnеl,v,God. Again Humе is thе spuг' tor thе сеlеbratес{ tish plrilosophеr haс1сlаirnесlthаг tlrе .,lкlrldgivеs nсl еvidеnсеof dеsigrrоf a d е i t y l i k е t h е С Ь г i s t i a ng o d . At first Darwin :rЬsorЬсdPаlеy's thinking сomplеtеly, and whеn hе сamе to douЬt thе Сhristian god, hе сontinuеd to think that Pаlеy was aЬsolutеly riglrt that thе orgаniс world shсlц,sdеsignlikе fеаrttrеs.In sеarсhirrgfor a сhаngе, Г)irrwin thсrеforе sought a mесhanism mесhаnism of еvсllr.rtitlnаrY fеaturеs' сould suсh irdirptаtiсlns.This mесhanisnr hе found in tlrаt ехpl;rin .Ihе Darwiniatl rnесlranism of tЬе Оrigiп of S1lесies does паtural sеlесtiol-l. not simply push for сhangе; it pushеs for сhаngе in а partiсular dirесtion, namеly' adaptivе асlvantagе,likе thе Ьеak of thе finсh. This is thе p
-М.R.

Pеarsоn,Karl (|857_\9З6) Kаrl Pеarson Was an important Bгitish stаtistiсian,a rnajor еnthusiastfor еugеrriсs(thе Ьeliеfthat onе саn аnd shor.rlddirесt thе сollrsе of human еvolшtion, partiсulаrlу Ьу геstгiсtionson Ьrееding),а widеli. rеrrdphilosophеr of sсienсe, ;rnd an impсlrtant influеnсе on thе histсlry of modегrr еvolutionаry tlrеory. Pеaгson was a Ьrilliant studеnt' graduating third rvranglеr (thе ordеrеd list in thе mаthеmatiсs honors сoursе) frоrrrСamЬridgе, but at thе samе timе hе imrrrеrsеdhimsеlf irr mаny Othеr аrеlrs of intеrеst,irrсlrrdingGеrmаrr litеraturе tO suсh alr ехtеIlt tlrat shortly tlrеrеaftегhе wzls offеrеd a post in thе СamЬridgе languasеs dеpartnrеrlt.Hс trairrеdfor thе law (in thе footstеpsof his fathеr) Ьut nеvеr praсtiсеd' stltltrЬесoming a prсlfеssorof mathеrlatiсs at Univеrsity Сol1еgе,I-ondсrn,his асadеmiс homе for lris wholе сarееr. Hе lесon suсh tоpiсs aS Мarх, Gеrпran rеturеd widеly tO nonасadеmiс audiеr-rсеs ligior.rsthought' аnс] soсial issuеs, suсh аs thе rеlirtivе rolеs of mеn аnd Wol1lеllilr soсiеtv. IJе wrotе а сlаssiс plrilosophiсalи,ork in thе posiтivisttra-

ditiorr, Тbе Grаmmаr оi gr.rеdtlrаt idеas ехist iп tl all is rеlativе to nrinсl-. a n е x t е r n a lw o r l d ' ' 1 l 9 0 , tially a produсt of thе h young AlЬеrt Еinstеin dе Pеlrsсlrt's work in tlrе l sсiеntifiс hеroes' foг hе сс (еstimatingonе variаЬlе1 ( е s г i n l а t i n gг h е с o n n е с t i t squarе tеst (еstimatingth for instаlnсе, that сlЬsеrv thаt thе nutnЬеrsof tlrеst w а s е m Ь r o i l е di n а f е r o с ist and statistiсianRonal major part this was a сlа also а diffеrеnсе Ьеtlvееrr r е l a г i o n sa n d F i s h е гu s i n g It is hаrd todа,vtо fееl ..lt еugеniсs. i s a f а l s еv i not a truе humаnism, wh mеn should rеplaсе a dаr thе full Ьеnеfitof mankin hцmаn krrowlеdgе'' (Pеa

еarly days of gеnеtiсs,mu and еasy mеthod of impr Pеarson,s sеminal wоrk ir all program hе inhеritеdl tiсs) and gеnеral mеntof' а Prosram shаrесЬ l r llis r Pearson's major сorrtr tеraсtion with hrs сollеag don, with whom in 1901 was thе most importаnt ( gist (witlr thе possiЬlеехс tion of Darwin's Оп tЬе (or synthеtiс thеorists)wl p r o Ь l е m s i n t h е 1 9 3 0 s .. major f:rсtorin еvolution sсalе projесts, mеаsuгing sЬow tlrе еffесtsоf sеlесt dimensions of сraЬs foun likе strrdiеsof сraЬs off th pеrimеnts to sее if his find (In partiсular, !Иеldon Ье nееds t() fееd end ttl lrvr.

I'еаrsoп hе spur, for thе сеlеЬratеd Sсot3ivеsno еvidеnсеof dеsign of a сomplеtеly,and whеn hе сamе think that Palеy was absolutеly kе fеaturеs.In sеarсhing for a thеrеforеsought a mесhanism s. This mесhanism hе found in l of thе Оrigiп of Speciеs does rangе in a partiсular dirесtion, thе finсh. lns toda1-.Riсhаrd Dаwkins, in t Palеy's sсllution is aЬsolutеly l to ехplain adaptation. But he .hе most important quеstion for ехplains adaptivе сomplеxity. 'аl Thеolrlgу, all goеs to dеmontехtЬoоk.

оn: lohn Мrrrrаy. York:Norton. I dп Attеmptto Ехplаiп thе iеraпсеto СаusеsNotu itl (Сollесtеd\l,t;r&s, vol. З). Londсln: 1Wоrks'vol.4).London:Rivington. ioп Hаuеа Pиrposе?СamЬridgе' -М.R.

.iсian'a rnajor еnthusiastfor еuJt thе сoursе of human еvolution, dеly rеad philosophеrof sсiеnсе, nodеrn еvolutionary thеory. 4 third wranglеr (thе ordеrеd list nЬridgе,Ьut at thе sаmе timе hе tеrеst,inсluding Gеrman litеraеr hе was offеrеd a post in thе d for thе law (in thе footstеps of r g а p r r , f е s s oor f m а г h е m a t i с sа t 'mе for his wholе сarееr. Hе lесuсh topiсs as Mаrх' Gеrman rеthе rеlativе rolеs of mеn and p h i с a Iw o г k i n t h е p o s i t i v i s tt г а -

dition, The Grаmmаr of Sсiепce (1892, sесond еdition 1900), in whiсh hе arguеd that idеas ехist in thе mind, and this is our sourсe of knowlеdgе. Hеnсе all is rеlativе 1сlmind-с(1hе fiеld of sсienсеis muсh morе сonsсiousnеssthаn ..law in thе sсiеntifiс sеnsеis thus еssеnan еxtеrnal world'' (1900,52), and tiаlly a produсt of thе human mind'' (1900, 36). It is no surprisе that thе young AlЬеrt Еinstein dеvourеd this volumе. Pеarson's work in thе fiеld of statistiсs will forеvеr kееp him in thе halls of sсiеntifiсhеroеs,for hе сontriЬutеdto dеvеlopingthе idеas оf linеar rеgrеssion (еstimatingonе variaЬlе givеn thе valuеs of anothеr variaЬlе) and сorrеlаtion (еstimating thе сonneсtion Ьеtwееn twtl vаriaЬlеs), аs wеll as thе fап-rousсl-risquarе tеst (еstimatingthе сhanсеs that variaЬlеs follow a spесifiс frеquеnсy, for instanсе,that oЬsеrvеd numЬеrs of malеs and fеmаlеs support thе idеa that thе numЬеrs of thе sехеsarе еvеnly balanсеd).Lаtеr in his сarееr Реarsсln was еmЬroilеd in a fеroсious сontrovеrsywith thе no-lеss-еminеntеvolution. ist and statistiсianRonald A. Fishеr ovеr tесhniсal quеstions in statistiсs.In major part this was a сlash Ьеtwееn two dominant pеrsonalitiеs,Ьut it wаs also a diffеrеnсеЬеtwееnrival aims-Pеarson using largе samplеsto infеr сorrеlatiсlnsand Fishеr using small samplеsto fеrrеt out сausеs. It is hard today to fееl sympathy ftlr onе as сommittеd as was Pеarsоn to ..It is а falsе viеw of humаn solidarity, a wеak humanitarianism, еugеniсs. not a truе humanism, whiсh rеgrеtsthat a сapaЬlе and stalwart raсе of whitе mеn should rеplaсе a dark-skinnеd tribе whiсh саn nеithеr utilizе its land fсlr thе full Ьеnеfitоf mankind, nor сontriЬutе its quotа to thе сommon stoсk of human knowlеdgе'' (Pеarson 1900, З69). Lеt us simply oЬsеrvе that in thе еarly days of gеnеtiсs,many thought that еugеniсsсlffеrеda rеlativеly quiсk and еasy mеthod of improving humankind. .й/есan аlso notе that muсh of Pеarson'ssеminal work in statistiсsstеmmеd from his еugеniс aims, an ovеr. all program hе inhеritеd from a major influеnсе (in his thinking aЬout srаtistiсs) and gеnеral mеntor' Franсis Gаlton (thе сousin of Сharlеs Darwin), and а program sharеd by his rival Fishеr. Pеarson's major сontriЬutiоns to еvolutionary thinking сamе from his intеraсtion with his сollеaguе at Univеrsity Сollеgе, !и. F'. R. (Raphaеl) !Иеldon, with whom in 1901 Pеarson foundеd thе journal Biomеtrikа. \й/еldon Was thе most important oЬsеrvational and ехpеrimеntal еvolutionary Ьiologist (with thе possiЬlеехсеption of Hеnry !Иaltеr Bаtеs)Ьеtwееnthе puЬliсation of Darwin's Оп the origiп сlf Spесiеs in 1859 and thе nеo-Dаrwiniаns (or synthеtiс thеorists)who Ьеgan sustainеdеmpiriсal work on еvolutionary p r o Ь l е m s i n t h е 1 9 3 0 s . . s И е l d o nw a s с o n v i n с е d t h a t n a t u r а l s е l е с t i o ni s а major faсtor in еvolutionary сhangе.To support this viеw hе tuгnеd to largеsсаlе projесts, пrеasuringfеaturеs of oгgarrisnrsthat hе hypothеsizеd might show thе еffесtsof sеlесtion.Stlmе of his most imPortant work wаs donе on dimеnsiоns of сraЬs found in thе Bay of Naplеs. Hе follсlwеd this work with likе studiеstlf сrаЬs off thе сoast сrfDеvon in Еngland аnd thеn turnеd to ех. pеrimеnts to sее if his findings сould Ье rеpliсаtеd undеr ссlntrollеd сonditiсlns. .V7еldon (In partiсulаr, Ьеliеvеd that mouth sizеs wеrе a funсtion of rеlativе nееds to fееd and tсl аvoid thе сlogging еffесtsсlf silt.)

801

802

Peаrsoп ]Wеldonturnеd to thе mаthеmatiсаlly giftеd Pеarson for hеlp in rеduсing his findings to mirthеtrrаtiсs,wЬiсh сould thеl.lЬе intеrpгetеdаnd translаtеd Ьaсk into еmрiriсаl сlаims. In сlnеimportаrrtfinding \й/еldon[lеliеvеdtlrat his Nаplеs сraЬs wеrе not ol1е singlе popul:-rtiсln Ьut two ovеrlapping pсlpulatioпs (sееfigrrrе)irnd shoц,,еdtlrat sеleсtionwas dir.iding thс populations ассording tсl diffеrеnt аdаptivе nееds аnd аdvanragеs.It ц,аs Pеarson who wаs aЬlе to show that Wеldon's findings Wеrе not random or mеaninglеssЬtlt forп-rеdtwtl ovеrlapping normаl сuгvеs' thus suggеstingthat it is indееd truе thаt sеlесtion is a major distorting influеnсе-distoгting in tl.rеsеtrsеof driving diffеrеnt indivrduals to diffеrеnt adaptivе solutions. Unfortunatеly' thе signifiсanсеof this rvork was sсlotrovеrshadсlu,еdЬ,va major сontrovеrsy that pittеd Wеldon and Pеаrsсlnagаinst ls7еldon'sformеr studеnt lХ/illiam Batеson. $7еldon and Pеarson, thе lеаdеrs of thе fасtion knсlwn as Ьiomеtгiсiаns,wеrе соrrrmitrеd(as lrrdеrrtГ)arwiпiar-rs) to tЬе Ьеliеi that thе сausеs of variation must Ье suсh аs to Pr()duсеvеry slight сhangеsin .iИhatеvеrtЬе сirusal faсtors might Ье, thе difthе mеmЬеrs of pt>pulatior.rs. fеrеt-tсеs prodtrсеd musr Ье '"'irtuallvсontirllloLls;othеrwisе, nattrrаl sеlесtiоrr сould not Opеratе (or wсlrsе, Ьесamе unnесеssary).At thе Ьеginning of thе twеntiеth сеntury, Batеson, who was sеarсhirrgfor thе сausеs of ','ariationаs a projесt in its owl-rright (thаt is, withсlut rеgard fсlr thе signifiсanсеof sеlес. tion)' sеizеd ()n thе rесlisсovеryof thе idеas of thе Morаvian monk Grеgor Меndеl. Неnсеforth Bi1tеsonWi1sthе lеaсJеroi thе British lVlеndеliar-rs, wlro Wеrе opposеd to thе Ьiсlmеtriсiansin thе bеliеf that tЬе signifiсantсhangеsin еvсllutionсaп-rеthгouglr сlnе-stеp,nеwly appеаring vaгiations,what t
Karl Pеarsсlп's сlosе fгiеll frсlr-rtаlЬrеadths' thс first gland) аnd thе sесond (Дс (Itаly). Thе first shtlrvslt t. еmpiriсally, саn Ье showп tuгnсd тсl Реагstln ttl givе arе tW() pоpulаtions' Ьrеа Wr-.ldсlr-r 189З.)

'ес1Pеtrrsonfor hеlp in rеduсing еn Ье intеrprеtеdаrrd rrzrnslаtеd finding\Х/еldonЬеliеvеd that his ln Ьut two ovегlapping populawas dividing thе populatiOns aс. tntagеs.It was Pеarson who ''vаs not rand
сan

)n сan с()mеinto play, arrd thеrе idеs,аnсl inсiееdmrtсh rеirson to :tunatеly'Ьеfсlrеthis rеаlly hаppеrsorrаlly)diеd sr-rddеnly,right B r i t i s hs t u d Ь o o k ( w h i с h r е с o r d s rrising rnatеr.iаlfor thе study of . a s t а t е dа n d , Ь l a m i n g B a t е s o n , lI.lstеd | г s u s с i u I n с s ьo г i г s v е г y lt Pеarson haс]thе sсlmеrvhat с1u.idеdinto two' onе pаrt of whiсh rk, and thе othеr to his aгсhrival еor1'rf Nаturсll Sеlесtion (1930)

Kаrl Pеarsсlrl'sсlсlsс friсnd Raрhaе| Wеldoп рroс1uсеdthеsе graphs of сraЬ frontаl Ьгеadths, thе first (top) from spесimеns сirught in Plymouth Sound (ЕngIаnd) аnd thс sессlnd (bottсlllt)fronr spесimеns саuglrt in thе t}ay оf Naplеs (Italy).Thе first shows а tvpiсal normill сr-lrvе.Тhе sесond, as \Wеldon disс-ovеrеd еrnpiгiсаIIy,саrr Ьс shсlr',n.tt аs thс сornЬir-rirtiсlrr oiгwo llrlrmаl сurvсs. WеIdon tllrnеd ttl Pеarstrn ttl givс a mathсmatiсirl analysis, shorving that at Naplеs thеге ilrе t\1.()popttlations, Ьrеaking аpагt rrndеr diffеrеnг sеlесtir,еprеssurеs. (Еrom Wсldon 1893')

Pbeпotуpiс Plаstiсitу offеrеd thе dеfinitivе Ьlеndins сlf Darwinian

nаturаl sеlесtion with Mеndеlian

gеnеtiсs. в|BLIoGRAPHY Fishеr, R. A. 1930. Thе Gепеtiсаl Thеorу of Nаturаl Sеlесtirlп. oхfсlrd: oхford Univеrsity Prеss. МaсKеnziе, D. A. 1981. Stаtistiсsiп Britаiп 186.\-19.]0:Тhе Sсlсiаl Сoпstruсtillп tlf Sсieпtфс Kпoшlеdgе. ЕdinЬurgh: ЕdinЬurgh Univеrsity Prеss. Pеarson, Е. s. 1936. Karl Pеaгson:Ar.rappгесiatiсlnof somе asресtsof his lifе anсl work. Part I. Biomеtrikа 28 193_257. |9з7-19з8. Karl Pеarson:An apprесiаtiоn of somс аspссtsof his ]ifе аnd work. Part 2. Biomеtrikа 29: 161_248. Pеarson, K. 1892, The Grаmmаr сlf Sciепсе. Lоndon: \)ИaltеrSсоtt. 1894. СontriЬutions tO thе mathеmatiсalthеory of еvolution. Philosllphiсаl Trапsасtioпs А 185: 7 1-110. \90О. TЬе Grаmmаr сlf Sсiепсе.2nd еd. Lоndоn: Blасk. Provinе, w. B. 1971. Thе Оrigins сlf Тhесlrеtiсаl Populаtiсlп Gutсtiсs. Сhiсago: Univеrsity of Сhiсagо Prеss. Rusе' M. 1'996' Мrlnаd to Мап: Тhе Сoпсеpt of Progrеss iп Еuolutirlпаrу' tsirllog1', СamЬridgе, МA: Наrvаrd Univеrsity Prеss. -l ed,2009. Philosophу аftеr Dаrшiп: А Rеаdсr. Prinсеton, N.J:Prinсеton Univеrsity Prеss. Wеldon, W. F. R. 1893. on сеrtаin сorrеlatеd vаriаtiоns in Саrсiпus moепсrs. Prrlсееdillgs сlf thе Roуаl Soсiеtу of Lсlпdoп 54: З18_З29. 1895. Attеmpt to mеаsurе thс dеаthrаtеduе to thе sеlесtivеdеstruсtiсlnсlf Сarсinus moеnas with rеspесt to а partiсLllar din.rеrrsion.Pкlсееdiпgs of thе Roуаl Soсiеtу of Loпdoп 57:360-З79. 1898. Prеsidеntiаladdrеss to thе Zoologiсal Sесtion сlf thе British Assoсiation. Тrаnsасtiсlпs of thе British Аssсlсiаtioll (Bristol), 887_902. -М.R' London:John Мurray.

Phеnotypiс plastiсity Рhеnotypiс plаstiсity is thе aЬility of an individual to еxprеssdiffеrеntfеaturеs undеr diffеrеnt еnvironrnеntal сonditions. For ехamplе, flоwеring plants produсе Ьroadеr lеavеswhеn thеy grow in shady сonditions, and fish аrе smallеr whеn thеy dеvelсlp in сrowdеd сonditions. Somе of thеsе сhаngеs rеflесt unavoidaЬlе сonsеquеnсesof edvеrsе сonditions' likе thе stunting of fish whеn thеy arе сrowdеd. Othеrs rеflесt gеnеral еffесts of faсtors likе tеmpеratlrrеon dеvеlopmеnt' as Whеn tadpolеs grow largег Ьеforе mеtamorphosing whеn thеy ехpеriеnсесoolеr сonditions. BLlt many ехamplеs of phеnotypiс plаstiс. ity arе aсtuаlly adaptations to a variаЬlе еnvirсlnпrеnt;thеy rеflесtthе еvolution оf a dеvеlopmеntal systеm that produсеs diffеrеnt traits Llndеr diffеrеnt сonditions Ьесausеno singlе trait is Ьеst srritеdfor :rll сonditioпs. Adaptivе plastiсity is onс of tlrе mсlst rеmarkaЬlе produсts of D:rrwiniаn еvolution. For adaptivе plastiсity tсl еvolvе,thеrе must Ье an есolсlgiсalsituation in whiсh no onе valuе of a trait Works wеll in all сonditiсlns.In addition, thе dеvеlopmеntal maсhinеry to Ьuild diffеrеnt tr:rit valuеs must Ье intеgratеdwith a sеnsory systеm that dеtесtsrеliaЬlе сuеs aЬollt thе prеvail-

ing еnvironmеntal ссlndi timеly mannеr. Givеn th suсh fеaturеsс
For еxamplе, damsеlflysр prеsеnсе of fish than in th fail to rеspond to thеir prt populations with a histo damаgе Ьy sесrеtingсorn dеtеr furthеr hеrЬivory;p taсks do nоt rеspond to lс Sесond' adaptivе plast sponds only to a partiсulа thе samе trаit in diffегепrr i n t h а t s a m е f а с t o r .I n s е с а r r е s t е d d е v е l o p m е n гi n r lеnging сonditions likе lol distinсt рhysiologiсalstatе thе animal ехits diapar-rs tеr diapausе in diffеrеnts P o p u l a г i o n so f t h е s e m еi pausе in геsponsеto diffе Adaptivе plastiсity еvol adjust thеir dеvеlopmеntt( in thе long run, individua gardlеss of еnvironmеntal phrasе ..in thе long run.''

P b епсltуpiс P l аstiс itу riarrnaturаlsеlесtionwith Меrrdеliirn

{ N,lturаl Sеlесtitlп.Oхford: Oхford 1865_19З0:TЬе SoсiаI Сtlnstruсtiсllttlf lLrrghUnivеrsit1,'Prеss. :сiatiсlnof stlmеаspесtsof lris lifе end зсiationof somе аsресtsof his lifс anсl .!Иaltеr Sсott. . l,ondon: Latiсаlthеory of еvolution. Phiksophiсаl d е d . L o n d о n :B l a с k ' i iсаI Po|lиlаtitl п G епеti сs. Сh iсago: уlt of Progrеssin Еuоlutiсlпаrу Birllogу' rеss. N|: Рrinсеtсln : А Rесtdеr.l)rinсеtсln, .еdvаriationsin Саrсiпus morп{ls' ' п d o l t5 1 : 3 l 8 _ 3 2 9 . lrrirtеduе tсl tlrе sеlесгivеdеstгr-rсtiсlnof гiсr-rlаrdimеnsioп. Pкlсееdiпgs of thе oologiсаl Sесtionof thе British b,4ssoci,ttitlп(Bгistol),8B7_9oz'

-М.R.

individualto ехprеssdiffегеntfеaturеs ns' For ехаmplе,flowеring plants pгOsl-rаdy ссlndititlns,аnd fislr аrе smallег ons. Somе сlf thеsе сhangеs rеflесt t.tn_ rditions'likе thе stunting of fish whеn Llеffесtsof faсtогslikе tеmpеraturеon largеr Ьеforе mеtamorphosing rvhеn mаny ехamplеsof phеnotypiс plastiсllе еnvirсlnmеnt;thеy rеflесt thе еvoluгoduсеsdiffеrеnttraits undег diffеrеnt ;t suitеdfоr аll сonditiorrs. lst rеmarkaЬiеproduсts of Darwinian .olvе,thеrе must Ье an есoIogiсаl sittlIn irddi_ woгks wеll in all ссlrrdiгitlrls. l build dif{еrепttгait virluеs must Ье dеtесtsrеliaЬlе сuеs aЬout thе prеvail-

ing еnvirorrrrrеntal ссlnditi
,90

P hуlogeпetiсs саpaсity to adjust its devеlopmеnt to ехprеss thе most suitaЬlе fеаtuге will pеrforr-rriust as rvеll аs thе individrrаl lvlrtl ехprеssеs tlrе samе fеatttгесonstitutivеly (that is, ехpгеssionis thе samе геgardlеssof сondition), Ьut it will outpеrform all thе individuаls who ехprеss unsuitaЬlе fеaturеs сonstitutivеly. Individuals with thе сapaсity to adjust dеvеlopmеnt havе high fitnеss in all сonditions, whеrеas inсlividuals with сonstitutivе dеvеlopmеnt pattеrns for thе samе sеt of fеatuгеshavе high fitnеss in somе сondiгions but low fitnеssill nrost сonditions.In гlrеlong rцn' ovеr many gеnеratiorrsor many loсations,individ_ uals with thе сapасity to adjust dеvеlopmеnt havе thе highеst аuеrсlgеfitnеss. of сoursе, а givеn individual dоеs not livе in many gеnеrationsor at mаny loсаtions at onсе' so in this сasе thе fitnеss Ьеnеfitsarе assoсiatеdwith thе сollесtion of gеnеs thilt сontrol thе plastiс dеvеlopmеntalsystеm.This point givеs phеrrotvpiсplastiсity its intеllесtualriсhnеss.Thеrе is аn еxtеnsivеЬody of thеory on how nаtuгal sеlесtiorron individuаl аnimals сan drivе еvolutionary сhangеs in dеvеlopmеntal systеms that involvе dozеns or еvеn hundrеds of gеnеs.This is not a trivial proЬlеm; a suссеssfulindividual doеs not pаss its еntirе gеnolrrеto its offspring.Thе idеntifiсationof nеtworks trf gеnеs thzrtсontrol dеvеlopпrеrrtand thе аЬility to mеasurе thе ехprеssion lеvеls of tlrosеgеnеs havе oреnеd thе dсlor to tеstingthis thеory in ways that wеге not possiЬlе in thе past. Thе study of plastiсity has a long history in еvolutionary biology and has аttraсtеd thе attеntion of somе of its lеading figurеs (sееthе аlphabеtiсalеntriеs ..Ivan Ivanoviсh Sсhmalhausеn''and ..Сonrad Hal !Иaddington'' in this voIurnе).Thеrе is a grоwing Ьodv of rеsearсhon thе есologiсаl сonsеqllеnсеs of adaptivе plastiсity, partiсularly in systеmsсlf irrdцсеddеfеnsеslikе that of thе wild parsnip, аnd thе many faсеtsоf phеnotypiс plastiсity сontinuе to inspirе rеsеarсh in this arеa' as wеll as in еvolutionary Ьiology. BIBLIOGRAPHY DeWitt, T. J., аnd S. M. Sсhеinеr,еds.2003. PhепсltуpiсPlаstiсitу:Ft,ttlсtitlttаl апd СonсеptuаlАpprсlасhes'Nеw Yсlrk:Oхford UnivеrsityPrеss. lVlinеr,B. G., S. Е. Sultan,S. G. Мorgаn,D. K. Padilla'and R. A. Rеlyеa.2005. Есologiсаlсonsеquеnсеs of phеnotypiсplilstiсity.Trепdsiп Есologу апd Еuсllutioп20 685_692. Pig'lirrссi. М. 2001. I'ltеltсltуpiс Plаstiсitу:BеусlпdNаtиrеаllс!Nиrturе.Baltimorе: Prеss. JohnsHoрkirrsUrrivеrsity Wеst-ЕЬеrhard''\,l.J. 2О0З.Dеuеlс-l|),'1епtаl Plаstiсitуапt! Еuсllиtitlп.Nеw Yоrk: -].T. oxford UnivетsityPrеss.

Phylogеnеtiсs Phylogеnеtiсsis thе tгaсing of gеrrеalogiсаlrеl:rtionshipsamong spесiеsаnd tlrе usе of thosе rеlationships to сlassify speсiеsand groups of spесiеsinto a hiеrarсhiсal trее оf lifе' It is part of thе praсtiсе of systеmatiсs,thе othеr Ьrаnсh of whiсh is taхonomy (thе distinguishingof spесiеsfrom onе anothеr anс]thе diagnosis of spесiеsЬoundагiеs).Phylogеnеtiсsis onе of еvolutionary

Ьiology's сеntral spесi othеr spесialty thаt hаs Мodеrn phyIogеnег of organisms must rеflе l а г i o n s h i p sе m е r g еf r o г split into two daughtеr spесiеs dividе and othе wlrilе othеrs spawn rnа thе Ьranсhing pattеrn с smallеr Ьranсhеsand ot Sеvеral сonvеntions8 The groups on adjaсеn сlosеst rеlаtivеs Ьесaus If tlrе Ьranсhеs arе at th if tliе adjaсent Ьranсhеs on thе highеr Ьranсhеs along а major Ьranсh o gеnus' frrmily, or Oroсr' t h е h i е г a r с h i с al la Ь е I i n si1iсаtion of all thе spес mation аЬоut thе rеIаr сallеd a natural сlassifiс Т h е t г a d i t i o n а |L r n n gеnerаl siпrilaritiеsЬut r ary rеlаtionshipsamoпg rесognizеs fivе сlassеsof and snakеs-Ьut doеs n< rеlationships to grouPs prise, givеn that thе syst Оrigiп of Spесiеs was p( whiсh of thosе groups al of thе trее, rеprеsеntin modегn rеptilеsto Ьirds t f o r m s ( s е еt h е a I p h a Ь е t for еvolution,'' and ..lVlo Although еmplоying е. onсе а сontrovеrsial idеа and ..Willi Hеnnig'' in thl thе thеory and praсtiсе сl infеrеnсе is еxtrеmеlyсhi Ьy analyzing fеaturеsof l aсtеristiсs of spесiеs rvitl likеly pаths through whiс of сornmon anсеstors.Tl from ехisting spесies, rvl-

Phуlogеnеtiсs эss thе most suitaЬlе fеaturе will l еxprеssеsthе samе fеaturе сon:gardlеssof сondition), Ьut it will unsuitaЬ1еfеaturеs сonstitutivеly. )pmеnthavе high fitnеss in all сonivе dеvеlopmеnt pattеrns for thе lсonditions Ьut low fitnеss ln most :ationsor many loсations, individг havе thе highеst аuerаgе fitnеss. е in many gеnеrationsoг at many s Ьеnеfitsarе assoсiatеd with thе dеvеlopmеntalsystеm.This point ;hnеss.Thеrе is an ехtеnsivе body lividuаl animals сan drivе еvoluthat involvе dozеns or еvеn hun_ r1a suссеssfulindividual doеs not dеntifiсation of nеtworks of gеnеs ) mеasurеthе еxprеssion lеvеls of 1thisthеory in ways that wеrе not y in еvolutionaryЬiology and has lg figurеs(sееthе alphaЬеtiсal еn.Сonrad Hal \Х/addington''in this сh on thе есоlogiсalсonsеquеnсеs ns of induсеd dеfеnsеslikе that of l е n o t y p i сp l a s t i с i t ус o n t i n u е t o i n 'lutionarybiolоgy.

,lепotуpi с P lаstiсitу: F uпсtioпаlапd гdUnivеrsityPrеss. Padilla,аnd R. A. Rеlyеa.2005. stiсitу.Trепds iп Есologу апd пd Nаturеапd Nurturе.Baltimorе: tsticitуапd Еuolutiсlп.Nеw York:

-1.r.

rl rеlationshipsamong spесiеs and э е с i е sа n d g r o u P s o f s p е с i е si n r o a praсtiсе of systеmatiсs,thе othеr ishingof spесiеsfгom onе anothеr hylogеnеtiсsis onе of еvolutionary

Ьiology's сеntral spесialtiеs, pеrhaps thе centra| spесialty, and thеrе is no othеr spесialty that has Ьееn as сontrovеrsial in its thеory and praсtiсе. Modеrn phylogеnеtiсsis prеdiсatеd on thе prinсiplе that thе сlassifiсation of organisms must rеflесta hiеrarсhy of еvolutionary rеlationships.Thosе rеlationships еmеrgе from еvolutionary history. A singlе spесiеsmay, in timе, split into two daughtеr spесiеs,еaсh of whiсh may split in thеir turn. As somе spесiеsdividе and othеrs do not, and as somе go ехtinсt without dеsсеndants whilе othеrs spawn many dеsсеndants, a gеnеalogy еmеrgеs that rеsеmЬlеs thе Ьranсhing pattеrn of a trее' with somе major Ьrаnсhеs produсing mаny smallеr Ьranсhеsand othеrs not. Sеvеral сonvеntions guidе thе usе of thе phylogеnеtiс trее in сlassifiсаtion. Thе groups on adjaсеnt Ьranсhеs of a gеnеalоgiсaltrее must Ье еaсh othеr's сlosеstrеlativеsЬесausеthеy sharе an immеdiatеly rесеnt сommon anсеstor. If thе Ьrаnсhеsarе аt thе tips of thе trее, еaсh group is an individual spесiеs; if thе adjaсеnt Ьrаnсhеsarе lowеr, еaсh group is a сollесtion of spесiеsfound on thе highеr Ьгanсhеs that еmеrgе from еaсh lowеr Ьranсh. All thе spесiеs along a major Ьranсh of thе gеnеalogy сonstitutе a group' whiсh might Ье a gеnus' family, or ordеr, dеpеnding on thе position of thе major Ьranсh, and thе hiеrarсhiсal laЬеling of thе various Ьranсhеsproduсеs a hiеrarсhiсal сlassifiсаtion of all thе spесiеs on thе trее. This сlassifiсаtion thus саrriеs information aЬout thе rеlationships of groups at all lеvеls to onе anothеr and is саllеd а natural сlassifiсation. Thе traditional Linnaеan сlassifiсations сrеatеd a hierarсhy Ьasеd on gеnеral similaritiеs Ьut madе no prеsumptions аЬout thе ехpliсit еvolution. ary rеlationshipsamong groups of spесiеs.For ехamplе' thе Linnaеan systеm rесognizеsfivе сlassеs of ехisting rеptilеs-turtlеs, alligators' tuataras' |izards, and snakеs-Ьut doеs not spесify thеir rеlationships to one anothеr or thеir rеlationships to groups known only from fossil spесimеns.This ls no surprisе' givеn that thе systеm was dеvisеd long Ьеforе Сhаrlеs Darwin's oп thе Origin сlf Speciеs was puЬlishеd. A phylogеnеtiс сlassifiсation would сlarify whiсh of thosе groups arе most сlosеly rеlatеd, whiсh arе сlosеr to thе basе of thе trее, rеprеsеnting oldеr linеagеs' and what arе thе rеlationships оf modеrn rеptilеsto Ьirds and mammals, as wеll as dinosaurs and othеr еХtlnсt forms (sее thе alphaЬеtiсal еntriеs ..Birds,'' ..Dinosaurs:Thе modеl systеm for еvolution,'' and ..Modеrn rеptilеs'' in this volumе). Although еmploying еvolutionаry rеlationshipsfоr сlassifiсationwas itsеlf ..Еrnst .!ИaltеrMayr'' onсе a сontrovеrsial idеa (sее thе alphaЬеtiсal еntriеs ..!Иilli Hеnnig'' in and this volume), thе modеrn сontrovегsiеs rеvolvе aroцnd thе thеory and praсtiсе of еstimatinggеnеalogiсalrеlationships.Phylogеnеtiс infеrеnсе is еxtrеmеly сhallеnging bесausе it attеmpts to rесonstruсt thе past Ьy analyzing fеaturеs of thе prеsеnt. Мorе spесifiсally' it usеs еxisting сharaсtеristiсsof spесiеs within an еvolutionary modеl to reсonstruсt thе most likеiy paths through whiсh thosе spесiеs divеrgеd from a tеmporal sеquеnсr of сommon аnсеstors. Thе hеart of thе сhallеngе is that onе has data only from ехisting spесiеs,whiсh oссupy thе tips of thе Ьranсhеs on thе trее, and

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Phуlogеnеtiсs fronr thеsе onе is аttеmpting to find аrsеriеsсlf nеstесlеvolutionary rеlationships and rесonstгt.lсttlrе Ьranсhing pattеrnsof tЬе еntirе trее. Тhе fundamеntal pгеmisе for rес
сaIlеd homoplasy, сan l Нomoplasy саn Ье pаrt usеd iп a phylogеnеtiс a of toцr statеs(thе Ьasеs plasy is quitе likеly at ar In mirпy сasеs whеrе r througlr сomЬinations с п1ovesa phylogеnеtiсaп of spесiesЬasеd on ovег DNA sеquеnсеs or a stа situations a roЬust phvl modеl tЪr how thе сhага Hегеin liеs onе sot-r сhz1rасtеrсhаnge fronr v fеrеnt rесonstruсtiоIlsol Ьasе_pairсhangеs in D} r h е n l u г а t i o n a lp r o с с s s modеls of сhаraсtеr сhа сhаraсtеrs suсh as thе sh sсars for plants, tlrе mс stеps involvеd in thе trа fеrеnt assumptions mаy diffеrеnt phylogеnеtiссс \Whеn rrranyсharасtеr еvеr, bе a singlе oЬvit.lц diffеrеnсеsamong spесiе distinguishing thе marry 1 Ьеst сhoiсе for thе data.. thrее s1.lесiеs, A, B, and (

r h е 1 . а г еd е n o r е di l l p r а с г C l n . l y Ь е с l o s е s tr е I n г i v lеnt to сonsidеring thе thl а с е n t r а |p o i n t Ь u r p | а с i n сlсrsеstгеlativеs,thеn tlrе l lеаds frt>пrthе сentгаl por аrе rhгее unгooге.l,Ili[ur B vеrsus С and D, A and еaсh сasе thеrе arе fivе Ьr: othеr, аnd within еaсh pi that rеprеsеnts thе сotтп along any of thе fivе Ьrar spесiеs.Тhis logiс сan Ье thе еnoгmous numЬеr of 1 (е.g.'sеvеn spесiеsсould l Thе gгеatеstsourсе t'f how to sеlесt thе Ьеsrсlrоi

Рhуlogепetiсs of nеstеdеvolutionary rеlation' of thе rntirе trее. ing thе phylogеnеtiсtrее is that lnapomorphiеs,whiсh arе statеs ..Hсlmology'' in this tiсal еrrtry сiеs through inhеritanсе from а :atеsеvсllvеd.Thе possеssion of s a group' аnd thе еmеrgеnсе of - ' r а | gl е n е a l o g yd i v i d е s i n t o t w o сall еlasmobranсhs(сhimaеras, :ir pеlviс fins;this сharaсtеr statе hеs thеm from othеr so-сallеd ..aЬsеnсе l thеir сharaсtеrstatе is r е m s е | v еdsе f i n е dЬ y с h a r a с t е r i s hе prеsеnсеof сlaspеrs dеfinеs a ieparatе frсlm thе othеr сhonmorе rеstriсtеdsynapomorphiеs .!7ithin thе еlasmoЬranсhs эints. t thе gills)аnd thе artiсulation of tmaеrаsand sеparatеthеm from ..F.ishеs''in this volumе for ntry :phiеsarе thus nеstеd onе within dеfinеd Ьy thе synapomorphiеs еntsirr thе gеnеаiogiсalpattеrn. е a r i s еf r o m d i f f е r е n tс o n v i с t i o n s sistеntWith thеsе nеstеd synapolrphiеsis not suffiсiеntfor rесonynapomorphiеsdеfinе groups of do not rеvеal thе loсation сlf thе t rеvеalwhiсh Ьranсhеs arе lowеr L,whiсh is сallеd rooting thе trее, r thе сharaсtеrstatеsof thе group е t o t h е е n t i r еg г O u p b е i n g а n a rd thе root is plaсеd at thе point guish thе ingroup from thе outlf еvolutionaryсhangе within thе iсh suЬsеquеntЬrаnсhеs еmеrgе. rds thе analysis to an additional l produсе diffеrеnt points for thе lons. r individualsynaPomorphiеs,partiсulаrly truе if thе сharaсtеrs that .Whеn ikеly to сhangе frеquеntly. lharеthе sаmе сharaсtеr statе not on аnсеstorЬut Ьесausеthе сharly in еaсh spесiеs.This сondition,

сallеd homoplasy, сan hiсiе gеnuinе rеlationships and suggеst inсorrесt onеs. Нomoplasy сan Ье partiсularly trouЬlеsomе whеn DNA sеquеnсеs arе Ьеing usеd in a phylogеnеtiс аnаlysis; a givеn sitе in thе mo!есulе сan have only onе of fсlur statеs (thе Ьasеsаdеninе, guaninе, сytosinе, or thyminе), and so homo. plasy is quitе likеly аt any singlе sitе if mutation ratеs arе сomparativеly high. In many сasеs whеrе сharaсtеrs arе laЬilе, groups сan Ье idеntifiеd only through сomЬinations of сharaсtеr statеs. But idеntifying groups in this way movеs а phylogеnеtiс analysis сlosеr to a morе traditional statistiсal grouping of spесiеs Ьasеd on ovеrаll similarity' whеthеr similarity is quantifiеd through DNA sеquеnсеsor a statistiсal mеasurе of morphologiсаl similarity. In thеsе situations a roЬust phylogеnеtiс analysis is possiЬlе only if onе postulatеs a mоdеl for how thе сharaсtеr statеsсhangе in thе сoursе of еvolution. Hеrеin liеs onе sourсе оf сontгovеrsy Ьесausе thеrе arе mаny models of сharaсtеrсhаngе from whiсh to сhoosе, and diffеrеnt mоdеls сan lеad to diffеrеnt rесonstruсtionsof еvolutionary histоry. In сasеs likе thosе that еmploy Ьasе-pairсhangеs in DNA sеquеnсеs'thе modеls arе Ьasеd on propеrtiеs of thе mutational proсеss' аnd using diffеrеnt propеrtiеs сan lеad to diffеrеnt modеls of сharaсtеr сhаngе. In сasеs likе thosе that еmploy morphologiсal сharасtеrssuсh as thе shapеsof Ьonеs in vеrtеЬratеsor thе numЬеr of Ьundlе sсars for plants, thе mсldеls arе Ьasеd on plausiЬlе assumptions about thе stеps involvеd in thе tгansfоrmation of onе сharaсtеr statе into anothеr; diffеrеnt assumptions may lеаd to diffеrеnt sеquеnсеsof synapоmorphiеs and diffеrеntphylogеnеtiссonсlusions. \Whеnmany сharaсtеrs arе Ьеing studiеd in many spесiеs,thеrе will rarеly, if еvеr, Ье a singlе oЬvious phylogеnеtiс trее сonsistеnt with thе similaritiеs and diffеrеnсеsamong spесiеs.Thе сhallеngе in praсtiсal phylogеnеtiс infеrеnсе is distinguishing thе many possiЬlе trееs and sеlесtingthе onе that reprеsеntsthе Ьеst сhoiсе for thе data. To undеrstand thе сhallеngе, сonsidеr that a study of thrее spесiеs' A' B' and С, must distinguish among thrее possiЬlе trееs or' as thеy aге dеnotеd in praсtiсе' topologiеs: A аnd B may Ье сlosеst rеlativеs,A and С may Ье сlosеst rеlativеs, oг B and С may Ье сlosеst rеlativеs. This is еquivalеnt to сonsidеring thе thrее spесiеsas еaсh oссupying a Ьranсh radiating from a сеntral point Ьut plaсing thе root of thе trее along onе Ьranсh. If A and B arе сlosеstrеlativеs,thеn thе root of thе trее must bе sоmеwhеrе on thе Ьranсh that lеads from thе сеntral point tсl spесiеsС. For four spесiеs,A, B, С' and D, thеrе arе thrее unrootеd, Ьifurсatirrgtrееs' сorrеsponding to сlosе pairings of A and B vеrsus С and D, A аnd С vеrsus B and D' and A and D vеrsusB and С. In еaсh саsе thеrе arе fivе Ьranсhеs;onе сonnесts еaсh pair ofсlosе rеlativеsto thе othеr, аnd within еaсh pair thеrе is onе Ьranсh from еасh mеmЬеr to а point that rеprеsеnts thе сommon anсеstor. Thе root of this trее сould Ье plaсеd along any of thе fivе Ьranсhеs' lеading to 15 possiЬlе topologiеs for only four spесiеs.This logiс саn Ье gеnеralizеd into a mathеmatiсal formula that rеvеals thе еnormous numЬеr of possiЬlе topologiеs for еvеn a small numЬеr of spесiеs (е.g.,sеvеnspесiеsсould Ье dеsсriЬеdЬy any of 10,395 possiЬlеtopologiеs). Thе grеatеst sourсе of ссrntrovеrsyin phylogеnеtiс analysis has Ьееn ovеr how to sеlесtthе bеst сhoiсе of topology for thе dаta in hand. onе possiЬility is

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Phуlogепеtiсs to usе parsimony аnalуsis, whiсh is Ьasеd on thе prеmisе tlrаt thе Ьеst сhoiсе is the topology with thе fеwеst total t-rumЬеrof еvoltrtiсlnаrvсhangеs irr tl-rесlrar. aсtеr statеs. Anothеr possiЬility is to usе mахiпruпr likеlilroсld, thе prеrnisе of whiсh is thаt thе bеst сhoiсе is thе topologY that mахimizеs thе prоЬаЬility of thе data in hand, givеn а partiсular modеl of еvоltrtiсlnаryсhаraсtеr сhangе. Thе most parsimonious topology nееd not Ье thе оnе with rhе highеstlikеlihood and viсе vеrsа, and this rеalizаtion hаs lеd tсl spiritеd and somеtirnеs-Ьittеr dеЬates Ьегwеen thе proponеnts of еасh mеthod. Мorеovеr, for mсlrе th:ln a modеst numЬеr of spесiеs,it is impossiЬlеto еnumеratеall thе possiЬlеtopolo. giеs to idеntify еithеr thе most parsimonious or thе onе with thе highеst likеlihood. In thеsе сasеs сomputationally intеnsivе mеthods, whiсh еxploit vаrious mathеmatiсal propеrtiеs of topologiеs, arе еmployеd to еstinratеtlrе bеst сhflifе (sееwww.tolwеll.org). Thеsе еfforts havе сhangеd our undеrstanding of rеlаti
Piltdown Мan Piltdown is thе nаmе g of human Ьгought to 1 сomplеtе mandiЬlе plu loсal lаlvyеr (сoulltr1' (1864-19I6| ot Uсkfiеl

сasuаllуirr lr gгаrсl1riг from Lеwеs irr еastеrlrS tог оf prеhistoriс rrrаtе (1864-1944), kееpеrof

London. For a sood 40 human fossil. Starting in 19.5З,hоu Piitdown wаs in fасt а d Pеtеnt anаtomistshаd st' s p е с i е s .T h е s k u l l w a s с l t an anthropoid аpе. Soг

вlвLIoGRAPHY Avisе,J. С.2004. МlllесцlаrМеtbсlds'NсltцrаIHist
Piltdсlц,'n

Piltdoшп Мап on thе prеmisеthat thе Ьеst сhoiсе is r of еvolutionaryсhangеs in thе сharmaхimum likеiihood, thе prеmisе of )gy that maximizеs thе proЬaЬility of lеl of еvolutionary сharaсtеr сhangе. ot Ье thе сlnе with thе highеst likеlias lеd to spiritеdand somеtimеs-Ьittеr mеthоd. Моrеovеr, for moге than a ) to еnumеratеall thе possiЬlе topoloous or thе onе with thе highеst likеlinsivе mеthods' whiсh еxploit various : еmployеdto еstimatеthе Ьеst сhoiсе. d ovеr thе past 25 yеars with thе ad. :. Thеrе is now a major еffort around 'еlationshipsamong all living organ(sееwww.tolwеЬ.оrg).Thеsе еfforts rtionshipsin many groups сlf organеtwееndinosaurs аnd Ьirds (sее thе э) to сhangingour еntirе viеw of ma..Сrustaсеans''in alphaЬеtiсalеntry hylogеnеtiс mеthсlds has provеd fеriologists'statistiсians,аnd сomputег rе projесtsin othеr arеas (sее www

Piltdown Мan P i l t d o w n i s t h е n а m е g i v е n t o w h a t h a d Ь е е n a s s u m е dt o Ь е а n е а r l y f o r m -]912. o f h u m a n Ь r o u g h t t o p u Ь l i с a t t е n t i o ni л A partial skull and an inсomplеtе mandiЬlе plus thе Ьorrеsof fossil manrmals wеrе unсovеrеd Ьy a l o с a l l а w y е r ( с o r ' r n t r ys o l i с i t o r i n Е n g l i s h t е r m i n o l o g y ) , С h a r l е s D a w s o n (\864-1916) of Uсkfiеid' Sussех (sееfigurе).Thе disсovеry Was madе rathеr саsually in a gravеl pit at Barkham Manor on Piltdown Сonrmon not far from Lеwеs in еаstеrn Sussех,southеrn Еngland. Dawson had Ьееn a сollесtor of prеhistoriс matеrial for Arthur (latеr Sir Arthr"rr)Smith Woodward (1864-1944), kееpеr of gеology аt thе British Musеum of Natural Нistory in Londсln. For a good 40 yеars Piltdown was сonsidегеda gеnuinе,if puzzling, human fossil. Starting in 19.53,howеvеr, сlosеr sсrutiny and tеsting dеmonstratеdthat Piltdown was in faсt a dеliЬеratеfaЬriсation. Right from thе Ьеginningссlmpеtеnt anatomistshаd statеdthat thе skull and mandiЬlе сamе from diffеrеnt spесiеs.Thе skull was сlеarly hutnan, Ьut thе mandiЬlе was oЬviously thаt of an anthropoid apе. Somе guеssеd thаt it was a fеmalе сhimpаnzее, and

iфii:i

thе faсе of еvolutionary Ьiology Ьy y othеr topiсs. СomЬining powеrful iistriЬutionsof spесiеshas lеd to nеw ng thе phylogеnеtiс distriЬution of lеrstandingof thе еvolution of сomation'' Ьy Josеph Trаvis and David Lеthodshаvе Ьееn еmployеd to study strainsof influеnza to Ье targеtеd in tigatе thе origin of novеl pathogеns lgy of Disеasе and Darwinian Меdimе).

rаl Нistоrу,апd Еuolutioп.2nd еd. iundеrlаnd, МA: SinauеrAssoсiatеs. |998. Сlаdistiсs: andD. М. \X/illiаms. Апаlуsis,2nd еd.oxford: Oхford )-0О2, Vertеbrаtе l-ifе' 6th еd. Uppеr

-I'Т. Piltdtlwn Маn.

81

812

Piltdслuп Мclп othеrs suggеstеd,сorrесtly' that it was a fеmalе oгang. At first, еvеn aftеr it w;rs еvident that Piitdown Wils аn artifiсial juхtaposition of unrеiаtеdspесiеs, thеrе sti[l Wаs no rеalization that its antiquity was аlso fгaudulеnt.Еvеntually it was shown that thе appеaranсеof grеat agе and fossilizationwas thе rеsult of staining with a rесipе of oхidеs of iron and manganеsе' аs wеll as сhromium. Piltdown сan Ье rеgardеd as a сandidatе for thе most spесtасular sсiеntifiс frаud of thе twеntiеth сеnturу. oddly еnough, suspiсion of fгаudulеnсеnеvеr fеll on Dawson, although hе hаd pursr"rеd a сarееr of dесеpti
that Tеilhаrd sift thгo an apеlikе сaninе too suggеstеdthat Tеilhar In 1914 Dаwson a from a piесе of fossili Thе сomplеtеly humo faсt еvеn thouglr it wz Thеn in 1915 Dаwsot at Nеrhеrhаll F'аrrrrht along with a rhinосеr pеnеd, Dawson hеld Nеthеrhall Farrn. Pilt of thе largеr сonсеrn son diеd tn 1976. Еvеn aftеr Piltdolvn possiЬlе dor"rЬtjust af than anothеr 40 yеa dеmonstratеd. In thе donеd southwеst tow( work on thе roof. Тhr thе initials of Маrtin , zoology and a fossil r Somе timе Wеnt by b( and thеrе at thе Ьotto a сollесtion of сarvеd ious Ьonеs thаt lookе known for his еlaЬor salary in thе musеum But it was nor until rh stood. Сеrtainlyonly : had aссеss to thе fossi sеntеd p.art of thе m musеum-sponsorеdех siЬlе that Dawson wаt solutеly surе of that n<

вlвLIoGRAPHY

Bеrgsоn,L1. 1907,I-'ёuo G е е ,H . 1 9 9 6 .B o x о f Ь о Nаturе 381:261_2 Millar, R. 1972.Thе Pilt Spеnсеr,F. 1990.Piltdo Prеss. T h с l m s o nK, . s . t 9 9 1 .P i Sсiепtist79, n
Piltdolaп Мап rlе orang. At first, еvеrr аftеr it t a p o s i t i o no f u n r е l a t е ds p е с i е s , wasalso fraudulеnt.Еvеntually аnd fossilizationwas thе rеsult r and rтangаnеsе' аs wеll as didatеfоr thе rnost spесtaсular .еrfеll on Dawson, although hе гs.Among his somе half-dozеn olvеd in сonсoсting rеprеsеntamap of an еarly iron forgе, and Сastlе, Sussеx,fгom an еaгliеr Vn to hаvе dippеd spесimеnslrе гomatе of potzrsh in ordеr to сt that hе had trеzltеdthе Pilt_ m sulfatе(iron alum) аnd thеn n sitе Ьut madе no еffort to sее - ' .H i s p r i n с i p a lе х p е г t i s еw а s i n tгtmеntat thе British Musеrrm inсornpеtеnt.Hе did Ьring in anatomy' a spесialistin hr.rnrzrn lllеgеof Surgеonsin Lоndon to struсtion of thе Piltdown matе. tvе Ьееn thе pеrpеtгator of thе |сеssto thе sourсе of thе faunal t h t h е h u m а n s k u l |а n d l r p е j a w . 'Piltdown find wаs announсеd ] thеrе.Нis еarliеr outlook hrrd :сordingto thе timеs of thеiг еxursе of human еvolution. In his for thе Frеnсh stanсе that mod..thе Еast'' quity somеwhеrеin е to Еuropе as invadеrs and ех. rndеrtals.This viеw was сlеarly а Dаrwinian outlook was nеvеr

that Tеilhaгd sift tlrгough tЬе rеsults' and it was whilе doing so thаt hе found an apеlikе сaninе tooth. Somе сommеntators on thе Piltdown sсеnario havе suggеstеdthat TеilhLrrd may havе Ьееn thе Pеrpеtrator of thе fraud. |n 1914 Dawson and Smith lfoodward for'rnd a Piltdown агtifaсt madе from a piесе of fossilizеdеlеphant Ьonе shapеd into thе form of a сriсkеt Ьat. .Woodwагd Thе сomplеtеly lrr.rmorlеss Srnith ассеptеdit аs a prеhistoгiс artifaсt еvеn though it wаs сlеаr that it hаd Ьееn shapеd by a mеtal сutting tool. Thеn in 1915 Dаwson Wrotе to Smith woodward that aсross the ll.ivеr Ousе at Nеthеrhall Farnr hе had found piесеs of a human skull and а nrolar tooth along with a rhinoсеros molar. Thеsе wеrе thеn саllеd Piltdown II. As it happеnеd' Dawson hеld thе position of stеward at Ьoth Barhkam Мanor and Nеthеrhall Fаrm. Piltdown II was not аnnollnсеd until t917, part|у Llесausе .War of thе largеr сonсеrn for thе issuеs сlf Worlсl I and pаrtly Ьесausе Dawson diеd in |9|6. Еvеn aftеr Piltdown Мan's fraudulеnt nаtuге wаs doсumеntеd Ьeyond any possiЬlе doubt jr'rstaftеr thе midpoint of thе twеntiеth сеntury' it was morе than anothеr 40 yеars Ьеforе thе identity of thе forgеr was сonсlusivеly dеmonstratеd.In thе mid-1970s сontraсtors сlеаrеd loft spaсе in thе аЬandonеd southwеst towеr of thе Natural History Musеum Ьеforе maintеnanсе work on thе roof. Thеrе thеy found a trunk with thе lеttеrs МAСH, сlеarly t h е i n i t i a l s с l f М a r t i n A . C ' H i n t o n ( 1 8 8 3 _ 1 9 6 1 ) 'w h o w а s d е p u t y k е е p е ro f zoology аnd а fossil гodеnt ехpеrt zrt thе timе of thе Piltdown fаЬriсation. Somе timе wеnt Ьy Ьеforе a rесеnt fossil rodеnt еxpеrt lookеd in thе trunk, and thеrе at thе Ьottom' Ьеnеathhundrеds оf vials of rodеnt dissесtions,wаs a сollесtion of сarvеd аnd stainеd еlеphant and hippopotamus tееth and varioцs bonеs that lookеd likе thе Piltdown сollесtion. Hinton had Ьееn wеll known for his еlaЬoratе praсtiсal jokеs and rеsеntеd thе handling of his .Woodwаrd. salary in thе musеuпr Ьy thе humorlеss аnd inсompеtеnt Smith But it was not until thе mid-1990s thаt Нinton's rolе was сomplеtеly undеrstood. Cеrtairrly only an insidеr at thе Natuгal History Мusеr.rmwould havе had aссеssto thе fossilsplantеd at thе Рiltdсlwn sitеssinсе thosе fossilsrеprеsеntеd part of thе musеum сollесtions assеmЬlеd as a rеsult of yеars.of musеrrm-sponsorеdеХсavationsin vаrious parts of thе world. It sееmsplausiЬlе that Dawson was Ьrought in on thе plot, Ьut thеrе is no way to Ье aЬsolutеly surе of that now. вlвLloGRAPнY

е FrеnсhJеsuitpriеst PiеrгеTеil. ,isitеdDаwson in 1908 whilе hе rgs'Sussеx.It was at tlrat rеtrеat ,ёаtrice(Сreаtiuе Еuolutioп) Ьу . а n d v е r у n o n m е с h a n i s t i сt г е a of еvolutiоnat all, it tеnds to Ье r 1913 Tеilhard rеturnеd to orе е visitеdPiltdown' whеге Smith еvingthе gravеl. Thеy suggеstеd

Bеrgson,H. |907. L'ёuolutiсlпсrёаtriсe. Pаris:Alсаn. Gее,H. I996. Boх of bonеs..сlinсhеs'' idеrrtityof Piltdownpalaеontology hoaхеr. Nаture З81:26|_262. Millar' R. 1972. Тhе PiltdсlшпМez. Nеw York: BaliantinеBooks. Spеnсеr,F. 1990.Piltdotuп:А SсiепtifiсForgerу.Nеw York: Oxford Univеrsity Рrеss. Thomson,K. S' 199l. PiltdownN4an:Thе grеаtЕпglishmystеrystorу.Апtсriсап Sсiепtist79, no. З: 194_2О1 . Wеinеr,.|. s. l9.'.'. Thе PiltdoшпFor.чеr\'.l-ondoп: oхford Univеrsitl'o..'1....u.

81J

814

PleistoсeneЕхtiпсtioпs

Plеistoсеnееxtinсtions Thе history of Iifе on еarth is punсtuatеd Ьy еpisodеs of rapid, widеsprеad ..Palеonехtinсtions in onе or morе grorrpsof organisms (sееthе nrain еssay tology and thе History of Lifе'' Ьy Мiсhaеl Bеnton and thе alphaЬеtiсalеntry ..Mass еХtinсtions', in this volumе). Onе of thе most notorious of thеsе еpisodеs is thе loss of thе so-сallеd Plеistoсеnеmеgafauna. Bеtwееn aЬout 50'000 yеars ago and 10,000 yеаrs ago' on all thе сontinents ехсеpt Afriса, most of thе lагgе (ovеr 40 kg mass) mammаls and Ьirds and somе of thе largе rеptilеs Wеnt ехtinсt. This notoriеty springs from thе fасts thаt it was among thе first wholеsalе ехtinсtions to Ье rесognized,it inсludеd somе of thе most spесtaсular mammals еvеr dеsсriЬеd, and human hunting appеars to havе playеd a major rolе in сausing it. Thе mammaliаn fаuna of 50,000 yеars aЕ]oinсludеd a high numЬеr of vегy largе spесiеs.Austrаlia сontainеd есhidnas of 20 to 30 kg in mass, kangaroos ovеr 200 kg in mass (thе largеstехtant kangaroоs arе aЬout 90 kg), a variеty of giant Ьirds and еnormous monitor lizards, and a gеnus of largе grazing marsupials namеd Diprotodoп that wеrе up to 2,000 kg in mass. North Amеriсa harЬorеd giant ground sloths, mammoths' and mastodons, and thе Еurasian fauna inсludеd saЬеr-tooths, woolly rhinos, сavе Ьеars' and thе giant Irish еlk. By 10'000 yеars ago ovеr 90 gеnеraof largе mammals wеrе ехtinсt. Although thеrе Was somе геgionаl hеtеrogеnеity,on all thе сontinеnts savе Afriсa thеrе was nеarly total еxtinсtion of spесiеs whosе individuals wеrе largеr than 300 kg in mass. In gеnеral,еxtinсtitrn ratеs Wеrе invеrsеly proportional to Ьody sizе; for ехamplе, in North Amеriсa thе еxtinсtion ratе for spесiеslargеr than 1,000 kg was 1007", that for spесiеsЬеtwееn З2 and 1,000 kg was aЬout 507", and tlrat for spесiеs Ьеtwееn 10 and 32 kg was on|у 20.Ь. Dееpеr analysis suggеststhat еxtinсtion ratеs wеrе invеrsеly proportionаl to rеproduсtivе ratе, whiсh is itsеlf invеrsеly proportional to Ьody sizе, mеaning that thе Plеistoсеnеехtinсtions wеrе vеry sеlесtivе,еliminating spесiеs with slowеr rеproduсtivе ratеs. In faсt, no othеr еpisodе of ехtinсtions assoсiatеdwith a glaсial-intеrglaсialtransition had еxtinсtion retеs as sеlесtivеas thеsе. This striking еpisodе of ехtinсtion was rесogпizеd as еarly as thе ninеtееnth сеntury' and its timing, сoinсidеnt with thе waning of thе last glaсiаl pеriod and thе start of thе prеsеnt intеrglaсial pеriod, suggеstеdthat сlimatе сhangе аnd its assoсiatеdеffесtswеrе rеsponsiЬlе.Pulsеs of ехtinсtions arе assoсiatеd with pеriods оf rapid сlimatе сhangе, еspесially thе transition fгom glaсial to intеrglaсial pеriods, thrсlughoutthе history of lifе. Мany fеaturеs of thе еnvironmеnt Ьеsidеstеmpеraturеrеgimе сhangеd in this transi. tion; sеasonality inсrеasеd as summеrs Ьесamе signifiсantly warrnеr' thе growing sеasonwas shortеnеd,haЬitats Ьесamеinсrеasinglyfragmеntеd,and thе gеographiс distriЬution of plants and plant assoсiationsсhangеd dramаtiсally, еspесially аt thе highеr latitudеs.Thе initial hypothеsеsaЬout сlimatе сhangе drеw upon all thеsе еffесts;that thе Plеistoсеnеехtinсtion ratеs Wеrе muсh highеr thаn thosе sееn at othеr glасial-intеrglaсialtransitions Was as-

сriЬеd to thе possiЬ trеmе than any of th Although thе еnvi playеd а rolе in thе t suffiсiеnt to ехplain onе thing, oхygеn is sеa surfасе tеmpеra and rapidity of this parеd with othеr tra twееn grazеrs (anlп woody vеgеtation)' should havе put gra сrеasеd in aЬundan Ьuriеd sеdimеnts in сomposition of plаnt highеr ехtinсtion rat rеgions of lowеr еxti A suggеstivеlinе с pеar at this timе on ratеs rosе dramatiсa pеriod aftеr thе arriv host of othеr spесiеs bonе pilеs with сIеa largе firеpits point с еxtinсtions. of сoursе, it may s with stonе WеapOnsс is сiеar that humаr-r dеnсе of kill sitеs(lar in what would havе t industry in mathеm h u m a n . o v е r k i l li s p l a сеrtainty if dеath rat hunting nееdеd to ас to raisе thеm aЬovе tions with rеspесtto l thе othеr hand, altho аftеr thе aгrival of ] ago), humans had Ье forе thе еvidеnсе of е tinсtion ratеs wеrе lo' lt mаy Ье that no s tudе' rаtе, and distril еffесts сamе into plaу no disсounting thе еf ing ехtinсtion еpisod

РIеistoсеnеЕхtinсtions

ерisodеsсlf rapid, widesprеad rs (sееthе main еssay ..Palеonlton аnd thе alphaЬеtiсal еntry . thе mсlst notoГious of thеsе nе mеgafаrrna.Bеtwееn аЬout ll thе сtlntirlеntsехсеpt Afriсa, rnd Ьirds and somе of thе largе Om thе fасts thаrtit was arrrong J' it inсludеd somе of thе пrost rman hunting appеars to hаvе inсludеda high numЬеr of vеry 20 to З0 kg ir-rmаss, kаrrgaгoos . o o sa r е а Ь о u t9 0 k g ) ' a v a r i е t y ' а n d а g е n u sr l i l a r g е g г a z i n g r to 2,000 kg in rnass. North noths, and mastodons, and thе l y r h i n с l s ,с a v е Ь е a r s , a n d t h е nеra of largе mammаls wеrе ехг o g е n е i t yо. n а l l t I l е с o n t i n е n t s n of spесiеswhrlsе individuals ехtillсtion ratеs Wеrе invеrsеly l r t h A m е r i с ar h е е х t i n с t i o nr а t е :hatfor spесiеsЬеtwееnЗ2 and i е s b е t w е е n1 0 а n d 3 2 k g w a s nсtion ratеs wеrе invеrsеly proinvегsеlypIopoгtionаl to Ьody W е r еV е г ys е l е с t i v ее'| i m i n a t i n g сt' 11оothеr еpisоdе of ехtinсrnsition hаd ехtinсtion ratеs as :сognizеdas еаrly as thе ninе'h thе waning of thе lаst glaсial l pеriod, stlggеstеdthirt сliпratе r s i Ь | еP. u I s е so f е x t i n с t i o n sа r е r a n g е .е s p е с i a I I vt h е t г а n s i t i о l t ut thе history of lifе. Many fеa- ' г е g i m ес h а n g е di n t h i s t r а n s i аmе signifiсantlv WaГmеr' thе nе inсгеasinglyfragmеntеd,and lt аssoсiаtiollsсhаngсd dranlat_ nitiаl hypothеsеsaЬout сlimatе ,lеistoсеnе ехtinсtion rаtеs Wеrе .intеrglaсiаltransitions wаs as.

сгiЬеd to thе possiЬiliry that this lаst trаnsition wi:lsmoге rapid and moге еxtrеmе than any of thе othеrs. Although tlrе еtrviroпгпеntаlеffесtsof а glасial.intеrglaсialtransition surеly playеd a rolе in tlrе dеmisе of thе Plеistoсеnеmеgаfauna' thеy do not appеar suffiсiеntto ехplirin thе magnitudе of thе еxtinсtiOnsnor thеir sеlесtivity.For onе thing' Oxygеll isotоpе studiеs сlf marinе Ьеnthiс dеposits, whiсh rеflесt sеa surfaсе tеmpеraturеs,do not support thе argumеnt thаt the magnitudе аrrd rаpidity оf this glасiаl-intеrglасialtransition wеrе unllsual whеn сomparеd with othеr transitions.Sессlnd,thе ехtinсtions did not disсгiminatе Ьetwееn gгazегs (arrimаls thаt atе grassеs) аnd Ьгowsеrs (animals that аtе woody vеgеtаtion)' and the haЬitat сhangеs assoсiatеd with this transition should havе put grazегs at а distinсt disadvantagе as woody vеgеtation inсrеasесlin аЬunсlanсе.Third' ехaminations of pollеn profilеs from longЬuriеd sеdimеnts indiсatе that although thеrе wеrе rapid сhangеs in thе сomposition of plant spесiеsnеаrly еvеrywhеrеaсross thе gloЬе, rеgions with highеr ехtinсtion ratеs did not еxpеriеnсеgrеatеror morе rapid сhangеsthan r е g i o n so f l o w е r е х t i n с t i o nr а r е s . A suggеstivеlinе of еvidеnсеis thе faсt that thе mеgafauna did nоt disappеar at this timе оn Nеw Zea1and аnd many oсеaniс islаrrds,Ьrrt ехtinсtion ratеs rosе dramаtiсallу on tlrеsеislands whеn humans arrivеd. \Х/ithina short pеriod aftеr thе аrrival of lrumans, all thе giant moas of Nеw Zea|and aпd a host сlf othег sресiеson thе oсеalriс islands Wеrе gonе' Dеposits of еnoгmous Ьonе pilеs with сlеar еvidеnсеof butсhеring and rеmains f
81.'

816

Prinсiplеsof Gеoiogy many sсiеntiststhis ma,vЬе a harЬingеr of whаt is tсrсomе in our nеаг fllturе as gloЬal сlimatе сhangе oссurs in ссlnjunсtionwith thе suЬstantialdirесt lnd indirесt еffесtsof humans ol1 thе naturаl world. в|вLIoGRAPHY Kеmp,T. s. 2005. Thе Оrigiп апс!Еt'сllиtiсlп rtf МаmmаLs.()хf
thеrе hаs Ьееn а stе sinсе thе СarЬonifеl rеvеrsе itsеlf in thе f planеt has Ьееn fit s. mаls; and Ьесаr.tsе а' lifе livе whеrе аnd v fossils havе not Ьееn

Priпсiplеs of Gеologу (СharlеsLyеll) Сharlеs Lyеll puЬlishеd thе first еdition of thе thrее volumеs of Priпсiplеs of Gеologу in 1830, 1832, Lrnd 18ЗЗ, rеspесtivеly.oftеn сallеd thе most irrfluеntial of all gеologiсal Ьooks, it is also arguaЬly anlong thе dсrzеnmost inflllеntial tехts еvеr on thе living world. Thе sr-rЬtitlе idеntifiеd it аs ..аn attеmpt to еxplain thе formеr сhangеs of thе еarth's suгfасе, Ьy rеfеrеnсеto сausеs now in opеration.'' In this attrnlpt Lyеll еxpliсitly assr-rrnеd that еvеr sinсе thе oldеst fossil-Ьеaringroсks thеrrknown had Ьееn lаid dоrvrr(rосks of thе Саrbonifеrous groups),thе saпrесаusеshаd Ьееrrat lvork On thе pianеt'ssuгfaсe, had workеd' morеovеr' in thе samе gеnеral сirсtlll]stаnсеsand with tlrе sirmе avеragе intеnsity, and so had produсеd thе samе sorts and sizеs of еffесts throughout this vast prеhuman past' on into thе prеsеnt' and so into an tn-Гhеrе dеfinitеly prolongеd futurе. was, thеn, in Lyеll's knowing есhсl of thе еightееnth-сеnturySсottish tlrеorist of thе еarth, Jаnrеs Hutton, no sign in any гoсks of thе еarth's Ьеginning or rthе attеmpt arе assеmЬlеd Ьy inquiring what сausеs arе now opеrating in thе physiсal and org:rniс worlds; third, thе attеmpt is сarriеd out' most ехtеnsivеly for thе сhangеs rесoгdеd in thе Tеrtiary formations of Еurсlpе and also, morе Ьriеfly, fоr thе sесondary and primary roсks. Aftеr thе fifth еdition of 18З7 this third part Was пrirс1еa sеparatе Ьook ini. tially titlеd Еlеmeпts of Gеologl'. L,vеl[was prеpаring а twеlfth еdition of PriпciplеswЬen hе diеd in 187.5.Thе main сhar-rgеs in tlrе trеatisе'stеaсhingsrvеrе rеquirеd Ьу his еmЬraсing in thе 1840s thе nеw с.loсtrinеof a glaсial еpoсh or iсе аgе and Ьy his partial, not vегy еnthusiаstiсaссеptanсеin thе 1860s of Dаr_ win and \ff/allaсе'snеw thеor), сlf tlrе origin of spесiеs Ьy natural sеlесtion. Thе еarly, most inf]uеntialеditions taught thrее пrain thеsеs.F.irst,thе ignеous and aqrrеousagеnсiеs hаvе always Ьеen in a providеntial|y dеsignеd' staЬlе, antаgonistiс Ьalаnсе, rlrе ignеous unlеvеling llrrсltlrе aquеous lеvеling thе еarth's surfaсе' sO thаt thеrе is соt1tinuеddеstrr.rсtion of old lаnd hеrе and formation of nеw thеге, with thе ovеrаll propсrrtiсrnof land to sеа stа,Ying roughly сonstant. Sесond,gloЬal сlinrаtесhangеsarе еntirеlyduе to rеvегsi[.llе сhangеs in thе distriЬution оf larrd and sеa rеlаtivе to thе polеs and еquattlr;

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Prinсiplеsof Gеology hat is to сomе in our nеar futurе n with thе suЬstantialdirесt and rld.

\lIаmmаls.oхford: Oxford ,tеrnаryехtinсtions:Statе of thе ' п l а t i с sЗ 7 : 2 1 . 5 _ 2 5 0 . се Аgе Ехtiпсtiсlпs апd thе -J.Т. lf Саlifоrnia Prеss.

thеrе has Ьееn a stеаdy gloЬal сooling duе to this сausе throughout thе timе sinсе thе СarЬсlnifеrous roсks wеrе forrnеd, a сooling that mLlst еvеntually rеvеrsе itsеlf in thе fllturе (sее figurе). Third, еvеr sinсе that rеmotе timе thе planеt has Ьееn fit somеwhеrе for еvеn thе highеst typе of organisms: mam. mals; and Ьесausеadaptational rеquirеmеntsalonе dеtеrminе what typеs of lifе livе whеrе аnd whеn, mammals must havе livеd thеn, еvеn though thеir fossils havе n
П) :lеthrее volumеs of Priпciples of lеly. oftеn сallеd thе most influLЬlyamong thе dozеn most influ. ..an attеmpt Ьtitlеidеntifiеdit аs s surfaсе,Ьy rеfеrеnсеto сausеs iсitly assumеdthat еvеr sinсе thе >ееnlaid down (roсks of the Сarn at Work on thе planеt's surfaсе, and with thе sаmе сirсumst:rnсеs 3 sаmе sorts and sizеs сlf еffесts o t h е P r е s е n t ,a n d s o i n t o а n i n n, in Lyеll's knowing есho of thе е а r t h 'J a m е s H u t t o n . n o s i g n i n 'nd. tеmpt to asсriЬе past сhangеs t
of thе first volumе of Сhаrlеs Lуе|L'sPrinсiplеsof Gеologу.To Thе frсlntispiесе avсlidhavingto aсссpta graduаllyсoсllingеarth (on thе Ьasisof thе palm trее fossilsfound around Paгis,thus suggеstinga Warmеrtimе in thе pаst),Lyеll proposеdhis thеory of сlimatе.Thе piсturеshоws а ruinеd Roman tеmplеon asсriЬеdthе dаrk Ьаndson thе thе ltаlian соаst.Lyеll аnd othеr gесllogists thе сolumns wеrе long immеrsеd wЬеn mollusks marinе by сolumnsto borings upright in thе sеa.F-orI,yеll'this and othеr еvidеnсеshowеdthаt thе land hеrе had suЬsidеdаnd thеn latеr risеn.ovеr thе wholе еаrth suсh loсal сhangеs соuld lеad, hе hеld, to сhangеsin thе distriЬutionсlf land and sеa rеlativеto thе polеs and thе еquatоr,ar.rdsо-land Ьсing a ЬеttеraЬsorЬеrof radiant solar hеat than watеr-ссluld сausеthе avеrаgеtсlтpегaturеоf thе planеtto сhangе. Thе stеadуplanеtaryсоoling sinсеthе СаrЬonifеrousroсks wеrе formеd, сooling indiсatеdЬy fossil finds' was duе to this сausation'hе taughtсаusаtionthat r,villrеvеrsеitsсlf аnd its еffесtsin thе long run of thе futurе.

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Prinсiplеsof Gеology plant typеs havе Ьееn сoming in, Ьy сrеation, and going out, Ьy ехtinсtion, throughout thе past, arе doing so in thе prеsеnt'and will сontinuе to do so in thе futurе, although at a ratе-pеrhaps onе spесiеs a yеar-that makеs it unlikеly that any spесiеsorigins hаvе yеt Ьееn witnеssеd Ьy сompеtеntnаturаlists. Еaсh spесiеsonly livеs and diеs onсе. As a sеparatесrеation it startsаt a singlе providеntially сhosеn spot' as a first pair or lonе hеrmaphroditе'and thеn sprеads its rangе, inсrеasеsits numЬеrs, variеs slightly to fit nеw сonditions Ьut not еnough to сhangе Or transmutе into anothеr spесiеs,and is еvеntually еxtinguishеd whеn it losеs out in сompеtitivе imЬalanсеs сausеd Ьy сlimatiс and othеr еnvironmеntal disturЬanсеs.Thеsе adaptаtional and есologiсal dеtеrminationsof thе timеs and plaсеs of spесiеsЬirths, livеs, and dеaths arе, thеn, togеthеr with thе сontinual сoming and going of avеnuеs (е.g.' land Ьridgеs) and Ьarriеrs (е.g.,mоuntain rangеs) to migrations, thе solе dеtеrminantsof thе diffеrеnt rеprеsеntationsat diffеrеnt plaсеs and pеriods of gгoups of spесiеssuсh as gеnеra' familiеs, and сlassеs. Thе first of thеsе thrее main thеsеs wаs thе lеast novеl, Ьеing, as l,yеll himsеlf insistеd, a modifiсation of Huttonian thеory. Howеvеr, thе сomЬination of thе sесond and third was а totally unprесеdеntеdproposal; no onе had ехpoundеd anything rеmоtеly likе it Ьеforе; and all thrее thеsеs togеthеr allowеd for an еntirеly nеw intеgration of Ьiogеography with gеology. Thosе fеw of Lyеll's сontеmporariеs whо сommittеd thеmsеlvеs to any сomprеhеnsivе aссount of thе еarth's physiсal and organiс historiеs mostly favorеd, in Britain еspесially, a сomplеtеly diffеrеnt synthеsis whеrеin thе еаrth had сoolеd and сalmеd irrеvеrsiЬly еvеr sinсе a moltеn fluid Ьеginning and had hеnсе Ьесomе progrеssivеly fittеr for highеr and highеr typеs of lifе, whiсh had aссordingly Ьееn сrеаtеd sporadiсally at spесial timеs in thе еarth's past in a progrеssivеsuссеsstonсonsummatеd Ьy man's appеaranсеas thе сrown of сrеation, sinсе whеn no furthеr speсiеsorigins had oссurrеd. Somе youngеr gеologistsand naturalists in thе nеxt gеnеration,with a yеn for grand synthеtiсthеorizing aЬout thе еarth and thе history and gеography of lifе upon it, saw thеmsеlvеsas сhallеngеd,aЬovе all, to adjudiсatеЬеtwееn thеsе two сonfliсting сomprеhеnsivеproposals madе Ьy Lyеll and his opponеnts. No onе took up this сhallengе morе sustаinеdlythan Сharlеs Darwin and Alfrеd Russеl \iИallaсе.In thеir indеpеndеntЬut strikingly parallеl agrееmеnts and disagrееmеntswith Lyеll and his opponеrrts,еvеntuatingin thеir indеpеndеnt Ьut rеmarkaЬly similar thеoriеs aЬout a trее of lifе and natural sеlесtion, thеy wеrе Ьoth arguaЬly morе influеnсеd Ьу Ьis Priпсiplеs tЬanЬу еvеrything еlsе thеy rеad put to€ ] еthеr. Lуe||,sPriпсiples сould Ье suсh a dесisivе influеnсе on thеm foг two rеasons. First, his novеl agеnda for gеology had lеd him to writе, as no onе had Ьеforе, nеarly 200 pagеsall aЬout spесiеs:what thеy arе and how thеy сomе and go in thеiг suссеssivе,сontinual Ьirths, livеs, and dеaths. It is thеrеforеthanks to Lyеll that Darwin's 1859 Ьook is сallеd Оп the origiп of Speсiеsand that \й/аllaсе's 1855 papеr is titlеd with a phrasе from Priпсiples....on thе Law \й/hiсh Нas Rеgulatеd thе Introduсtion of Nеw Spесiеs.''Sесond' Lyеll's spесiеsсhap-

tеrs Opеn with a dtlzеn pl p o s i г i o n с l f t h i s s у s t е mi s s с l L y е l | ' sv е r s i o n i n с l u d сеstr}/'and thеrеforе r:rп o l .t h i s trаnsmutаtiOnism сrеatеd fiхеd spесiеs irs trеаtmеnt of spесiеs and spесial сrеationisthypot sivе issuеsaЬout spесiеs. Darwin, having еmЬr (halfway through his v with Lyеll's thеоry of N 4 a l t h u si n 1 8 З 8 , h е w 1836, сamе to fаvtlr s struсtеd his own first ехpoundеd Ьy l,yеll. Sо еmЬraсеd Р riпсip lеs, w l ing RoЬеrt СhаmЬеrs' torу of Сrеаtioп. But\ vеrsus spесial сrеаtionl

rаisеd Ьy Vеstiges or Ь gеnеrationand nесеssa dеntly to vеry similar t two mеn сonvеrgеd or (trееlikе)spесiеstransl gins that Was morе сol and vеry gеnеrally n adaptationist spесialсr Lyеll prеsupposеdDar intеgratiсln of gеology l l a с е ' s1 8 5 5 е s s а y )a n d t sеntation;thе distribut familiеs, ordеrs, and sс and plaсing of spесiеs Ьarriеrs tсl migratiotls mеntor was in indеpе do not dеtеrmirrеthat l mon anсеstriеsand so .s7hеn th dеtеrmining. what Daгwin саllеd nl formations, Ьoth wеrе logiсal, gеographiс,an tions' This last сonvеr p r е с е d е dЬ y y е а r sо f o l and disagrееmеnts'Wlt

Prinсiplеsof Gеology , anсlgoing out' Ьy ехtiIlсtion, -rt,аnd will сontintlе to do so in ' е с i е sа y е a r - t h a t n t a k е s i г u n ,itnеssеdЬy сompеtеnt naturala sеparatесrеation it starts at a aiг or lonе hеrmaphгoditе, and v:lriеsslightly to fit пеw сonditе into anothеr spесiеs, and is сornpеtitivе imЬalаrrсеs сausеd 'anсеs.Thеsе adaptational and aсеsof spесiеsЬirtЬs, livеs, and I сolning,аnd gtling,of ;'rvеnuеs tirir.rrangеs)to migrations, thе ons at diffеrеntplaсеs and pеriiеs' and сlassеs. iеastnovеl' Ьеing, as Lyеll himory. Hсlwеvеr' thе сorr-rЬination lеrrtеdproposаl;no onе lrаd ехrrd all thrее thеsеs togеthеr al_ 3еographywith gеology. Thosе l thеmsеlvеsto any сomprеhеnniс histоriеsmostly favorеd, in nthеsis lvhеrеin thе еarth had noltеn fluid Ьеginning аnd hаd and highеr typеs of lifе, whiсh spесialtimеs in thе еarth's past man's appеaranсеаs thе сrown gins lrad oссurrеd. tlrе nехt gеnеration'with a yеrr r and thе history :rndgеography lbсlvеall, to adjudiсatеЬеtwееn | s r n а d еЬ y L y е l |a n d h i s o p р o :stair-rеdly than Сhаrlеs Darwin )nt Ьut strikinglу parаllеl agrееopp()nеnts'еvеrrtuаtingin thеir аbout a trее of lifе and natural rеnсеdЬy Ьis Priпсiplеs than Ьy lluеIlсеon thеm for tlvo rеasons. 1 to Writе'as no onе had Ье[orе, .rеand how thеy сornе and go in lеirths.It is thеrеforе thanks to l Оrigiп of Spеciesand that !Val_ Priпсiplеs:..on thе Law Whiсh :s.''Sесotld,Lyеll's spесiеsсhap_

..Lаnlaгсk's systеm.''14еll'sехteгsopеn witЬ a dllzеtl pagеsоn what Ье сallеd p
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Prinсiplеs of Gеology BIвLIoGRAPHY НеrЬеrt, S. 2005. Сhаrlеs Dаrtuiп, Gеologist. Ithaсa' NY: Сornеll Univеrsity Prеss. Нodgе, М.J.s. 1991 . Оrigiпs апd Spесiеs: А Studу of thе Historiсаl Sourсеs сlf Dаrluiпism апd the Сoпtехts of Somе Оtbеr Асcouпts of Оrgапiс Diuersitу frсlm Plаto апd Аristotlе oи. Nеw York: Garland PuЬlishеrs. 2ОО9. Dаnuiп Studiеs: А Tbеorist апd His Thеoriеs iп Tbеir Сoпtехts, Aldеrshot, UK: Ashgatе PuЬlishing. Hodgе, M.J. s.' and G. M. Radiсk, еds. 200З. Thе Саmbridgе Сompапiсlп t,l Dаrшiп. СamЬridgе: CamЬгidgе Univеrsity Prеss. Laudan, R. 1987. Frсlm Мinеrаlogу to Geolсlgу: Thе Fouпdаtiсlпs rlf а Sсiепсе, 1650_18з0. Сhiсago: Univеrsity of Сhiсаgo Prеss. Lyеll, С. 1830_1833. Priпсiplеs of Gеologу: Bеiпg ап Attеmpt to Ехplаiп tbе Former Сhапgеs iп thе Еаrth's Sиrfаcе bу Rеferеnсе tсl Саusеs Nrltu iп Оpеrаtioп,3 vols. London: Jоhn Murray. Faсsimilе rеprint' Сhiсаgo: Univеrsity of Сhiсаgo Prеss, 1990. Rudwiсk, М.J. s. 2ОО8. Worlds bеforе Аdаm: The Rеаlnstruсtiсlп of Geohistorу in -].H. the Аge of Reform. Сhiсago: Univеrsity of Сhiсago Prеss.

Raсе

Thе сonсеpt of raсе is < ogy. It has Ьееn usеd t( r a t i o n а I i z еt h е m u г d е r a n d а s а r е a s o nf o r o n е t o t h е p r е s е n td a y . F г o n е t i с a l I yЬ а s е dp o p u l а r Ь е с o m еа s o с i o с u I t u r a i n t е r p r е t а r i o n sa n d с o tions of ехisting raсial ( Сlassifiсаtionsof hur his sons Wаsonе tradi dаnts of Сanааn wеrе Нam had disrеspесtful modеrn traditiсln in thе Johann Friеdriсh Blumr into fivе groups: Сauса Nеgroid (Ьlaсk),and Al o f t h е с o n с е p to f г a с еi I to mid-twеntiеthсеntu singlе spесiеs'rесogniz In thе ninеtееnthсеn wеrе ехplorеd Ьy man1 sсeпt of Мап, аnd Sеle Еnglishman hе had liш сеrtainly did not think most of his сontеmporа о f l i v i n g i n с o l d е rс l i m h u m a n s .D а r w i n w а s i s е x u а l s е l е с t i o nH . е thr f е r е n t .с u I r u r a l I yh а s е d t u r е s Ь е l n gе s t a Ь I l s h е Darwin also еxplorе сolonization and suЬju bеliеvеd thаt Еuropеan Was not' сontrаry to sol

Ithасa,NY; Сornеll Llnivегsity Prеss. Studу оf thе Histtlricаl Sourсеs of her Асссlt,tпtsof Оrgапiс Diuеrsitу Garland PuЬlishеrs. t Нis Thесlriеs iп Thеir Сoпtехts. . Тhс Саmbridgс Сtlmpапitlп tсl ty Prеss. ',у: Thе Foипdаtioпs of а Sсiепсe, 'gсlPrеss. еi|lg ап Аttеmpt to Ехp!аiп thе Rеfеrспсеto Сlttsеs Nrltt' iп , Faсsirnilе rеprint, Сhiсago: Univеrsity : The Rессlllstruсtiollof Gеobistсlrll irt

f СhiсаgоPrеss.

-J.H.

R

Raсе Thе сonсеpr of raсе is onе of thе most сontrovеrsial in all еvolutionary Ьiology. It has Ьееn usеd to justify thе slavеry of Afriсans in thе Nеw !7orld, tсl rаtionalizе thе murdеr of millions of Jеws, Slavs' and Gypsiеs Ьy tliе Nazis, and аs a rеason for orrеgroup to opprеss anothеr throughout hunrаn histor,v to thе prеsеnt day. From its usе in plant and aninral Ьiology to rесoрinizеgеnеtiсally Ьasеd population variation witlrin a spесiеs'thе сonсеpt of raсе has Ьесomе a soсiсlсцlturаlсlassifiсаtionof human divеrsity rvith higlrly сhargес1 intеrprеtations and сonnotations. Thе Ьiologiсal foundations and appliсations of ехisting raсial divеrsity arе morе сompliсаtеd аnd nuanсеd. Сlassifiсationsof humans сan Ье found in antiquity; thе story of Noah and his sons Was onе traditional way of еxplaining human divеrsity (thе dеsсеndants of Сanaan Wеrе supposеd to Ье сuгsеd and Ьlасk bесausе his fathеr Hanr had disrеspесtfullystarеd at Noah whеn hе was nakеd and drunk). Thе modеrn tradition in thе usе of tlrе tеrm fсlС€ StdttSwith thе Gеrman physiсian (|752-1840), who dividеd thе human spесiеs Johann Friеdгiсh Blr-rmеrrbaсh (whitе), into fivе groЦps: Сauсasian Мongolian (yеllow), Malayarr (Ьrown), Nеgгoid (Ьlaсk),and Amеriсan (rеd).This wаs not vеry diffеrеntfrom thе usе of thе сonсеpt of rасе in plаnt аrrd animаl Ьiology in thе ninеtееnthand еarlу to rr-rid-twеntiеthсеnturiеs' in whiсh raсеs Wеrе с1еsignatеdas suЬgroups of lr singlе spесiеs, rесognizеd Ьy a fеw visiblе diffеrеnсеs in сolorаtion or form. In tlrе ninеtееnthсеlrtury thе еvolrrtionагyехplаnаtions of rасiаl divеrsitу wеrе ехplorеd Ьy marry sсholars, notaЬly Ьy Сharlеs Darwin in his Thе Dеscеnt of Маn' апd Sеlectioп iп Relаtioп to Seх (1871). Although as a good Еnglishrnаn lrе had littlе douЬt of thе supеriority of his or,vngrollp' Darwin сеrtainly did nоt think that humans arе dividеd into sеvеral spесiеs.Unlikе most of his сOntеmpor:lriеs,hе did not think that thе mсlrе stringеntdеmands of living in соldеr сlinratеshad lеd tо thе irrtеllесtuаlsrrpегioгityof thе whitе humans. Darwin was inсlinеd to asсriЬе raсial diffеrеnсеsto thе еffесts of sехual sеlесtion.Не thought thаt diffеrеnt isolatеd groups would dеvеlop diffеrеnt' сulturally Ьasеd rrotionsof Ьеauty, whiсh would lеаd to diffеrеnt fеaturеs Ьеing еstaЬlishеdas thе norm in еzrсhgroup. Darwin also еxplorеd thе argumеnts offеrеd at thе timе to rationalizе thе сolonization and suЬjugationЬy Еuropеansof othеr grolips. AlthotrghDаrwirr Ьеliеvеd that Еuropеan сivilization was supеrior to thosе of othеr groups' hе Was not' сontгary to s()mеmisrеtldings of his writing, an аdvoсatе of gеnoсidе' 821

822

Rасе Hе suggеstеdthat а major faсtor in any triumph Ьу Еuropеan сolonistswas thе asymmеtriсalsprеad of disеasе,with \VеstеrninfесtionsЬеing еspесiallydangеrous for nativе pеoplеs without a history of ехposurе. It is also worth noting that Darwin dеplorеd thе ill еffесts
that arе probaЬly r proЬaЬly arе) that. rеspond to thе trad groups with diffеrе Whеn spесifiс gс еnсеs Ьеtwееn grot сasе, еspесiallywh tional faсtors arе с prеting IQ sсorеsi mеasurе' diffеrеnс Еduсational histor thеsе sсorеs, and i oг oссupy diffеrеn thе Ьasis of thosе с A сommon сouг in IQ sсorеs сan l lеvеl of variation l Ьasеd. If thеrе arе Ьеhavе likе thе р within groups Ьut Todаy proЬaЬly tеnt thе notion of ; ..Ьlaсk,'' еVеn thol think that it is otf lеad and hаvе lеd l сonfirm timе and somеwhat isolatеd stoсk' Gеnеtiс ana Ьеar instеad an ol thеsе distinсtionsа tations to lсlсal сo havior, intеlligеnс Givеn thе drеad its foundation, it u of history. But сoг tеnding that thеrс Thosе distinсtions in thе DNA sеquе important points . that thеy oссur as , ditional raсial сat thеsе сontinuе at i that hаvе сausеds gеnеtiс variation. l udiсеs Ьеhind raсi to Ье сonsignеdto

Rасe ph Ьy Еuгopеаrlсolonists Was thе r infесtiorrsЬеirrgеspесi:llly dаri_ ехposurе.It is also worth rroting : pеoplеs.гаking,up unаttr.rсtivе nsumptionof alсohol. liсial vегsiсlnof raсial thinking ruеd intсrtlrе twеntiеth сеntuгy, s of thе N;rtitllrаlSoсialists.Irсlrrs irr thе war against tlrе Ni.rzis Ltsfor tlr
that arе proЬaЬly not involvеd with thе disеаsеЬut arе loсаtеd nеar gеnеs that ..gгoups''сorprobaЬl1.arе) thаt diffег ЬеtwееngroDps.lп somе of thеsесasеs' rеspond to tlrе traditional raсial сlassifiсations,Ьut in otlrеrs thеy сorrеspond to groups with diffеrеnt еthniс hеritagеswithin a traditional rirсе. Whеn spесifiс gеnеs саnnot bе idеntifiеd, it is vеry diffiсult to аsсribе diffеrеnсеs Ьеtwееn groups' raсial or еthniс, to gеnеtiс Ьasеs Ьесausе it is oftеn thе сasе,еspесiallywhеn сlnесonsidеrstraditional raсial groups, thаt many additional faсtors аrе сoпfoundеd with group iсlеntity.Thе сontrovеrsyovеr intегpгеtingIQ sсorеs is a prсltЪundехirrrrplе.Еvеrrif Wе put аsidе whаt IQ sсorеs mеasurе' diffеrеrrсеsin аvеragе IQ sсtlrеs among grollps lravе many sourсеs. Еduсational history and soсiсlесonomiсstratum' among othеr variaЬlеs,affесt thеsе sсorеs, аnd if individuals frсlnr diffеrеnt groups havе diffеrеnt historiеs or oссupy diffеrеnt soсioесonomiс strаta, it is diffiсult, if not impossiЬlе,on thе Ьasis of thtlsеdаtа alonе to аsсriЬеthе diffеrеnсеsto aпy singlе сausе. is that twiгl studiеshаvе shorvn that variаtion A ссlmmon с()tllltегаr8umеnt in IQ sсоrеs сan havе а gеt1еtiсfсltrrrdаtion.Aithough this is thе сasе' this lеvеl of variаtion dеsnot mеan prеtеnding thаt tlrеге аге nO gеnеtiс distinсtions among gгotlps of humans. Thosе distirrсtionsarе сlеar, whеthеr thеy arе obsеrvaЬlе in faсial fеaturеsor in thе DNA sеquеnсеsof mutаtions that affесt susсеptiЬilityto disеasе.Thе important points arе that thеy rеprеsеnta fraсtion of human variation and that thеy oссur as muсh among groups within traditiona] raсеs аs among traAs migrаtion, miхing, and mating сontinuе (and ditional raсial сatеЕ]oriеs. thеsе сontinuе аt аn ассеlеratеdratе in thе modеrn world). thе distinсtions that havе саusеd sо muсh ill lviil rеprеsеntan evеr snrilllеr fгaсtion of human gеnеtiсvariirtiсln.Ultimatеly, Wе ilrе forсеd to сonfront thе faсt that thе prеjfoundеd and that thеy also ought udiсеs Ьеhind гaсial thinking arе сr"rlturalIy to Ье сonsignеd to thе dustЬin of history.

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Rаup в|вLIoGRAPHY Сavalli-Sforza, L. L., and F. Саvаlli-Sfоrza. 1995. Thе Graаt Humаlt Diаsportts:Thе 17istorу of Diuеrsitу апd Еuolutiоп. Rеading, МA: Addison-.Wеslеy. Cavаlli-Sforza' L. L.' P. Mеnozzi, аnd A. Piazza. |994.Thе Historу аttd Gеogrсtphу of Ниrпап Geиes. Pгirlсеton,N]: PrinсеtotlUrlivеrsitr-Prеss. .Гhе Dеsсепt of Мап, апd Sеlесtioп iп RеIаtioп /о Seх. London: Darwin, С. \87 1. John Мurrаv. 2005. Nrll bу Gеlrcs Аloпc: Htпu Сultнrс Riсhеrson, P. J., аnd R. Bсlr'с]. Сhiсago: Univеrsitr, of Сhiсаgo Prеss. Humап Е,uolutioп. Trапsformесl Rosеnbеrg' N. A., J. K. Pritсhard, .|.L. \WеЬеr,L{. М. Сann, K. K. Kidd, L. A. Zhivotovsky, and \4. F.еldman.2002. Gеnеtiс struсtltrеrlf humаn populаtions. Sсiеnсe29ti: 2.]81_2385' Stеarns.S. С.. еd. |999. Еt,сllиtiсlпill Hеаlth апd Disеаsе, Oxfсlrd: Oхford -М.R. апd J.T. Univеrsity Prеss.

Raup, David М. (Ь. I9З3) a сеntral figurе in thе rепirissanсеof palеorrtolrlgy'sсontriЬuDavid Raup \'v,i]s еvolutionary thеory that took plасе in thе 1970s. His work has primation to rily foсusеd on applying statistiсal analysis and сomputеr siшЦlаtion tO thе fossil rесord, and thеrеfoге hе lras pionееrеd tесhr-riquеsthat dеpart from thе traditional palеontologiсal oriеntation toward dеsсriptivе studiеs of taхonomy' morphology, and stratigrаph)..ArguaЬly Raup's most importаnt сontriЬution to еvolutionar'vthеory has Ьееnto draw attеntiolrto thе possiЬilitythat thе Ьroad pattеrns of spесiеsorigination (spесiation)аnd ехtinсtion arе lirrgеly govеrnеd Ьy stсlсhastiсor random proсеssеs.Thе impliсations сlf this suggеstion arе {ar rеасhingand hаvе сontriЬutеdgеrrеrallуto a сhallеrrgеto thе uЬiquity of nеo-Darwinian proсеssеsas thе gеnеГatorof еvolutionаry novеlty. Raup's original training was in fairly traditional paleontology, and by his own aссount hе Ьеgаn his саrееr fullу stееpеdin thе rrеo.Daгwiniаnгеnеtsof thе modеrn synthеsis.Aftеr rесеiving his PlrD from Harvard in 1957 (whеrе hе studiеd undег Bеrnhard Kummеl and Еrnst Mavr), hе rrlovеd to Johns Нopkins Univеrsitу аnd еr,еntuаlly to thе Univегsitiеs of Roсhеstеr irnd Сhiсаgo. By thе mid-1960s hе hаd сomе to rесognizеthе potеntial сomputеrs had to hеlp palеontolоgists modеl сomplех Ьiologiсal proсеssеs involving many variaЬlеs. Irritially Rаup foсusеd on ссrmputеrsimulatiorr of mollusk shеlls, whiсh allowеd him to ехplorе gесrlrrеtriссonstrаints on morphology Ьy ехamining both rеal and hypothеtiсal shеll morpholоgiеs. AIthough this it [ес1to аppliсawork fеll squaгеly in thе tradition:rl study of systепrzrtiсs, tions that opеrrеdnеw horizons for mathеmatiсallylitеratе palеontologists. Thе turning point сamе in 197\ whеn Raup pаrtiсipаtеdin a syrnposirrmat ..]vIodеlsin Palеthе Gеologiсal Soсiеty of Amеriсa's ilnnuаl сonfеrеnсеtitlеd ontology.'' lt was during this mееting that Nilеs Еldrеdgе and StеphеnJay Gould's thеory of punсtuatеd еquiliЬrium was unvеilеd,and аt thе instigation of Thomas J. М. Sсhopf, Raup аnd Gould еrnЬarkеdon а lifеlong сollаboration. Thе nеxt vеar Rar:p, Gould, Sсhopf, alrd thе populatiorrЬiologist Dаniеl .Woods Holе oсеanographiс Institution,whеrе thеy sеt SimЬеrloff mеt at thе

thе Ьold tirsk of finс1ing thе widеly hеld e'srrm inсomplеtе doсumеnt, fossil rессlrd might rrre r е s u l t t l f r a n d r l n lг a t h с this idеa, Raup Wr()tеa lшtionary diаgrarтs' rvl nеW spесlеsor goll]gе) urе on pagе 826). Thе Raup and his grоup ar v i г t u a l l v i d е n t i с а lt t l t r this did not prсlvе that g е s tt h e t t h е r еw e s t t t lt ч е l е с t iеr t i t n е s s l,l l w а v l n t h е y е a r st h а t [ o I ' l r r t i o n а r yр a t t е г n : !i l,n с r е v i s е d ,i r h a d а n l l j o r sil rесord. By thе еarlу tion, whiсh hе dеtеrm О r i g i l t t l f S p с с i t ' s|' л '

Raup Ьеgаnехamining Hе and Sеpkoski suЬjе r l l а j o r е х t i n с t i о nе r ' с t w е r е w i p е d ( ) u ti l l a s m i l l i o n - y е a irn t е r v l r Ii sr iсir1'tlЕ f х r i n с t i t r ni n Ьoth in sсiеntifiс iгсlс rivеd from thе indеpе fоr а massivеехtratег and Теrtiary pсrit-'ds R a u p e n d S с p k o s k i .as r e r 1 ' .a n d t h i s s p а г k е t : ma jor ехtinсtions.Тhе v е r s i a l p o s s i Ь r I r tryh a г srraining thе path сlt еl faсtors tl,rathavе a nor

R а u p ' sс o n t г i h u t i t l on drаwiгrg attеntion importаnt rolе ill thе oppositе of еvolution howеvеr' lvas Raup's simulation of mасroе rеsеarсh. Thе tесhniqu . r n d I 9 7 0 s e r е n o \ \ 'r U t о l o g у . l l n d R а u p . sp r

to|ogyinto thесompu

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Тllе Grеаt Huпшn Diаsporаs:.ГЬе MA: Аddison-\Х/еslеy. 994. Тhе Historу апt! Gеogrаphу nivеrsityPrеss. :itlttiп RсIаtiolt to Seх. Lorrс]оn: s Аlэпе: Нoш, Сиlturс l i v е r ь i t yr э fС h i с ; r g оP r е s s . N4. Сarln, K. K. Kidd' L. А. ] struсturеof human populations. Disеаsе. Oхford: Oхford

-М.R. апdJ.Т.

iаnсе of palеоrltology'sсontriЬuгhе l970s.His work hаs pгimаrnd сomputеr simulation to thе tесhniqttеsthat dеpаrt froп-rthе rd dеsсriptivе studiеs of taхony R а u p ' sm о s t i m p ( ) г t e nсt o n r r i W аttеnti()n to thе possiЬilitythat liation)аnd ехtinсtion arе largеly Т h е r m p l i с e t i o n os f t h i s s u g g е s rеrallyto a сhallеngе to thе uЬiqLtoгof еvolutiollаrуnovеlty. itionаl palеontology,and Ьy his j i n t h е n е t l - D e г w i n i i l lt е l ] е r so f ) fгom Harvard h 1957 (whеrе гnst Мavr)' lrе movеd to Johns Univеrsitiеs of Roсhеstеr and :сognizеthе potеntiаlсornputеrs l Ьiologiсal proсеssеs involving oшputеr simulation of mollusk :trlссonstraintson morphology еll mсlrphologiеs.Although this lf systеmаtiсs'it lеd to appliсаLtiсallylitеratеpalеontologists. ) p . l г t i с i p а t еidr ra s y t t l p o s i u ma г )nfеrеnсеtitlеd ..Modеls in Palе\ilеs Еidrеdgе and Stеphеn Jay s u n v е i l е t ie. n d а t r h е i n s t i g а t i o n nЬarkеdon a lifеlorrgсollaЬoгаl thе population Ьiologist Daniеl rphiс Institutiоn, wlrеrе tlrеy sеt

thе Ьold task of finding nеW Ways of looking at thе history of lifе. Сhallеnging thе rvidеlу hеld assLrrnptiorr that thе fоssil rесord was a poorly prеsеrvеdand inсоmplеtе doсurnеnt. Raup сonсеivеd thе kеy insight that tlrе pattеrns in thе tЪssilrесord might rlrаkеnlorе sеnsеif thе1'wеrе undегstood to Ье in pаrr thе rеsult of randсlгt-t rathеr tЬаn striсtlу dеtеrministiсproсеssеs'In ordеr to tеst this idеa, Raup wrotе a сonlputеr pr()gramthat would prodtrсеsimulatеdеvo. lutioni.rrydiagralns, r-',,hеrе thе likеlihood of a partiсular linеagе produсing a nеW spесiеsor going схtinсt Was sеt as a randomly gеnеratеdvariaЬlе (sееfigurе on pаgе 826). Thе rеsults,wlriсh u,еrе puЬlishеd tn197З, Wеrе striking: Raup and his group irrguеdthat randomly gеnеratеdphylogеnеtiсtrееs wеrе virrLlаllyidеntiсаl to thе pattеrns foLrndin thе aсtual fossil гесord. Although this did not provе thаt еvolution Was nесеssarilya random proсеss' it did suggеstthat thеrе was no rеasol1to аssuп1еthat traditionаl сausаl faсtors,suсh .rs sеlесtivеfitnеss,alwаys dеtеrn-rinеd thе ссrursеof еvolution. Irr thе yеars that followеd, Raup сOtltinuеd to dеvеlсlp modеls of nraсroеvo. lutiorraryPattеrns' аnd whilе thе original stoсhаstiсwork was disсussеdand rеvisеd,it had a major impaсt On thе way palеontologistsapproaсhеdthе fos. sil rесord. By thе еarlу 1980s Raup's intеrеstsеttlеdOn thе proЬlеnl of ехtinсtion, whiсh hе dеtеrminеd had Ьееn dramatiсally ovеrlookеd sinсе Оп thе Оrigiп rlf Spесiеs. ln сollаЬoration rvith his сollеagrrеJ. John Sеpkoski Jr., Raup Ьеganехamining Sеpkoski'smassivеdаtaЬasеof thе mаrinе fossi]rесord. Hе аrndSеpkoski suЬjесtесlthis сlatat() statistiсalarralysisand dеtеrпrinеdthat mаjor ехtinсtion еvеnts-mass ехtillсtions rvhеrе up to 95% of ехisting taхa wеrе wipеd out in a short pеriod of timе-appеaгеd to oссur at rеguiar 26million-yеаr intеrvalsin thе history of lifе. Thе rеsultingpuЬliсation, ..Pеriodiсity of Ехtinсtions in thе Gеologiс Pаst'' (1984),аttrасtеdsignifiсi.rnt atrеntion Ьoth in sсiеntifiссirсlеs аnсl fronr thе populаr mеdia. In part this attеntiondе.s7altеr rivеd from thе indеpеndеnt disсovеry Ьy аnd l-uis Alvаrеz of еvidеnсе for a massivе ехtrаtеIrеstriаlimpaсt at thе Ьoundary Ьеtwееt-t thе Crеtaсеous and Tеrtiary pеriods-thе ехaсt momеnt whеn thе dinosaurs wеnt ехtinсt. Raup and SеpkoskiЪ аllаlуsis plaсеd a trrajorехtinсtion еVеntаt thе K-T Ьсlundary, and this sparkеd an intеnsе rеnеwal of dеЬatеs сonсеrning thе сausеs of major ехtinсtions. Тlrе pеriodiсity hypothеsis also, horvеvеr,raisеd thе сontro. vеrsial possiЬilitv that mass еxtinсtions,whiсh hаvе had а nrajor rolе in сonstrainingthе pаth of еvolution tlrrouglroutlifе'shistory, may Ье dеtеrminеdЬy faсtorsthlrt hаvе a nonЬiologiсaland еvеn ехtratеrrеstrialorigin. Raup's сontriЬution to еvolutionarythеory is signifiсantand rеstspгimarilv on dгаwirrgаttеtltionto thе possiЬiliry.that n
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Anyonе looking at this piсturе would think it a pеr{есtly normal phylogеntrс rеprеsеntation of a group that spесiatеd for fairly nоrmal adaptatiоn-Ьasеd ..triloЬoids'' rеasons. In faсt, it is of an imaginaгy group of and was gеnеratеd Ьy random faсtors' thus throwing into quеstion thе argumеntation of many еvolutionary сlaims. (From Raup and Gсluld 1974, З19.)

вIBLloGRAPHY Raup, D. M. [1986] |999. Тhе NеtпеsisАffаir: A St
Ray, John (1,62

John Ray was thе lt madе important сor dеsсribing and сlass Ьility that thе еаrth mеmЬеrеd for his v naturе was dеsignеd Ray was Ьorn in was thе villagе Ьlaс and wеnt up tо Trin Trinity in 1649 Ьut fusеd to aссеpt thе i rеady arrangеd to b WillughЬy' with wh Whеn'0ИillughЬy dit to Blaсk Notlеy. Hе Ray originally stu on thе сlassifiсatio (1686_1704).Hе hеl whiсh thе rolе of a s1 сal сharaсtеr. Hе еm сotylеdons Ьut insist work out thе pоsitio сallеd spесiеs wеrе m spесiеs thеmsеlvеs Ьt tеndеd his сlassifiсаt Ray was intеrеstе еarth's surfaсе, althо studiеs posеd for thе hts Мiscellапeous Di World in 1692. Noz now ехposеd on dry fесtеd thе еаrth's sur longеr alivе, and hе impliсations of еxtin rеmains of living сrе Ray always Ьеliеv attaсkеd Dеsсartеs'

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lеr1есtly normal phylсlgеntiс y normal adаptation.Ьasеd :riloЬoids''and wаs gеnеraсеd Ьy argumеntation of mаny 74' з19.)

Storуof thе Dеаth of Diпсlsаurs Ъrk:W. W. Noгton. !i Nеw York: \V. W. Nоrton. n u l r r i o nа n dе v o l u t i o n ot iogv, SуstеmаtiсZoolrlgv 2Зz

R a u p ,D . M . , s . J . G o u l d ' l . . J . M . S с h o p f ,а n d D . S S i m Ь е r l o f f1.9 7 3 .S t o с h a s t i с modеlsof phylogеn}' and thееvolutionof divеrsitу. 8 ] ' no. Jtlurnаlrlf Gеt.>logу 5: 52.5-542. Raup,D. М., and l. J. Sеpkoskilr. 1984'Pеriodiсityof ехtinсtionsin thе gесllogiс past'PrОсееdiпgs of thc NаtirlnаlАсаdеm1'of SсiепсеsUSА 81: 80l_80.5. -D.Se.

Ray, John (1'627_1'7О5) Bгitаin. Hе John Rаy wаs thе lеаding naturаlist in lаtе-sеvеntееnth-сеnturу madе irnportant сontriЬutions t
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Rесаpitulаtiсllt .Wisdom gеnеration. Flis of God Мапifеstеd iп thе Works of the Сrеаtion (1691) Ьесamе onе of thе sепrinal works оf British nаtural thеology. Неrе Ray arguеd thirt thе struсtuге of lil.ing spесiеs pгoviсlесlеvidеnсе that tlrеy rvеrе dеsignеd Ь1' а wisе аnd Ьеrrеvolеntgod' This inсludеd thе huп-ran spесiеs, thе е;-еand thе harrсl Ьеing vеry oЬvior"rssigns of dеsign, Ьtlt Ray hеld that еvеr1'spесiеs was adaptеd Ьoth in its plrуsiсаl form and in its instinсts to a partiсular еnvironmеnt. B|вLIoGRAPHY (iаrrrЬridgе: Ravеn,С. Е. |942,.|сlhпRау, Nаturаlist:Н is I'iiе апd \X/rlrk, (iaпlЬгiсigе UnivеrsityPгеss. Ray, J. 1686_1704.HistrlrittPlаlttrtrиlп.3 vols.l-ondоIl:Н. F.аiгthornе. |691. Тhе Wisdoш of Gсld l\Iапifеstеdiп thе Wоrks of thе Сrеаtiоп. London:SalnuеlSmith. 1692..МisсеllапеousDisссltlt,sеs Ссlпсcrпiпgthе Dissolutiсlпапd Сhапgеsof -P.l.B. tbе World.[-сrndor.r: Sап-ruсl Smith.

Rесapitulation Rесapitulation thеory has its roots in thе еaгly.ninеtееnth-сеnturуGеrman world piсturе of nаturе philosophv or Nаtur|lhilсlsсlpbiе.Еndorsеd Ьy poеts likе Johann \Wolfgangvon Goеtlrе, philоsophеrs likе Friеdriсh Sсhеlling,arrd sсiеntistslikе Lorеrrz Okеn, Nаturphilrlsophiе saw dеер Ьonds Ьеtwееn diffеrеnt parts of tlrе цюrld that wеге rеvеаlеd Ьv undеrlуitlg pаttеrns сlf frlrt-n. Thе similaritiеs (homologiеs) Ьеtlvееn thе skеlеtal forеlimЬs сlf vегtеЬгatеs and thе six.sidеd symmеtry of tlrе snowflakе wеrе firvoritеехamplеs. Nаtиrphiloso1lhеп(somе of whom wеrе еvolutiorristsаnd somе of whom Wеrе not) saw parallеls Ьеtwееnthе dеvеlopпrеntof thе individual and thе dеvеlсlpmеnt of lifе on еaгth, Ьoth of whiсh supposеdly shсrwеdprogrеss to a Ьеttегеnd irnd wеrе stlmеhotl,с]rivеnЬy a kinс1oi rvorld forсе сlr monlеlltllm. Thе ftrllеst ехposition of tЬis kind of thinking сamе from thе Srviss-Amеriсaniсhth,vologist Louis Agаssiz, who dесlarес]thаt lifе еxhiЬits a thrееfold parallеl in whiсh thе rangе of organisms alivе today forms thе third string: ..Onе lnaу сonsidеr it as hеnсеfoгthprovеd thаt thе еmЬryo сlf thе fish during its nunlеrous familiеs, anс1thе typе of fish in its planеtary histoг1,,, ехhiЬit anаlogous plrаsеsthrсlugh rд,hiсl-r onе mаy follow tlrе samе сrеаtivе tlror.rghtlikе a gшiding thrеad in thс'study сlf tlrе сonnесtitln Ьеtwееnorganizеd Ьеings'' (Agassiz 1 8 8 5 , 1 : З 6 9 _ З 7 0 ; s е еf i g u r е ) . Agassiz Was еvеr an opponеnt tlf еvolutionary idеas, Ьut aftеr thе puЬliсation of Оп thе ()rigiп сlf Speсiеs in 18.59,ехpесtеdly it rvas not lоng Ьеfсlrеthе parallеlism was t.rkеn up and givеn tl firmly еvolr.rtionllryintеrprеtation. This oссurrеd in сhе rlrаjorw
A

[,ouis Agаssiz'sfavrlгitсс from tсlp to l)ott()lrr.. Wс i Thе tаil staгtsdiphyсегс h е t е r о с е г с з{lu p p е r| . l | ' t on thе rigЬt (B),from to I i v i n gf i s h .f r o m " p r i m i t ( l а s tt o a P P с . l ri n t h е f . l s tail, sturgесlrrrr,ithа hеtс

pаrtiсularly to thе fасt t history thаn ir"rсхploring rтuсh сlf thс еr'olrrtion Haесkеl's Ьiogеnеtiсl:rw This thinking also sp stanсе' sigrrifiсаntin thе сholоgist and еduсatitln sеt stagеsof с1еvеlopm forсе гhеm Ьеyond thеr firrпi1. progrеssionist,v prеva[еnt tlrinking aЬor formеr Wеrе stаgеsthro A п-rattегof somе intсr fit with rеsресt tO rесap

Reсаpitulаtioп iп thе \Yсlrks of tЬе Сreаtiсlп Bгitish naturai thеology. }{еrе еs pror,idеdеr'idегrсеthat tlrеy od. This inсlrrdеd tlrе hunran v i o u s s i g n so f d е s i g n , Ь u t R а y i t s p h y s i с a lf t l r n lа n t i i n i t s i n -

lпd Work, (iarтЬridgе: rrdorr:H. F.aiгtiloгr-rе. tЬc \Yоrks of tbс Сrсаtiсltl. tg thе l)issohttiсlп апd Сhапges of

-PI.B.

гly-rrirrеtееrrth-сеntury Gеrrnart lhilosсlpbie. Еndorsеd Ь1,poеts :rs iikе Friеdriсh Sсhеlliпg, аnd a saw dееp Ьonds Ьеtwееn difly undеrlyingpattеrns of form. :еlеtаlforеlimЬs of vеrгеЬrаtеs wеrе favоritеехamplеs. Nаtur:sand somе of whom wеге not) Lnсlividual аnd thе dеvеlopmеnt rowеd progгеssto a Ьеttеr еnd ioгсе or momеntun1.Thе fullеst thе Swiss.AmеriсаniсhthyoloхhiЬits a thrееfold parallеl in ms thе third string: ..Onе may yo of thе fish during its numеr.ary history, ехhiЬit analogous rе сrеativеthought likе a guidэеnorganizеdllеings'' (Agаssiz ry idеas, Ьr-rгaftеr tlrе puЬliсatеdly it wаs not long Ьеforе thе olutionа ry il1tеrprеtаtion'This . giе dar Оrgаnismеп (1866) Ьу y hе arguесl that thе dеvеlop_ dеvеlopn-rеnt of thе raсе or the ;allеdЬiogеnеtiсlаw: ontogеny w a s r а k е nu p w i t h е n t h u s i a s m laggеratiоnto say that tlranks

L o u i s A g а s s i z ' sf a v o г i t ес a s сo f r е с a p i t u l a t i o (nG o u l d 1 9 7 7 , 6 7 ) 'O n t h е lеft(A)' frtlnr tсlp to Ьottоm, Wе sсс thе dеvеlopmеntof thе tеlесlstflatfislrРleиoпесtеs. rhе tаil startsdiphyссrсal(thеvеrtеЬrаеgo right to thе tip), thеn Ьесomеs hеtеroсеrсa[ (uppегloЬс laгgеrthеn lowеr),аnd еnds hoпioсеrсal(loЬеsеqual). on tlrе riglrt (B),frtlm tсlpto L]otto'n'wс havе thе tаils of thе аdults of thrее living fish, froln ..prin-ritir,е'' (Iirstto aPpеаr ilr rl-rеfоssilrесord)to ..аdvаnсеd,. (lastto aPpеarin thе fossil гесоrd):Protoptcrus(lrrпgfish) with а diphyсеrсai tail, sturgеonwith a hеtеrtlсеrсаl tаil, аnсlsalmon with a hсlmoсеrсaliаil.

рartiсular|ytо thе faсt that pеoplе wеrе mtrсh mrlrе intеrеstеdin trасing lifеЪ lristorythan in ехploring есologiсaland еvolutionaryсausal faсtorsfor сhangе, muсh сlf thе еvolutionary work rlf thе latе ninеtееntlr сеntury owеd morе to Haесkеl's Ьiogеnеtiс law thirn it did to Darwin's natural sеlесtitln. Тhis thinking alsсl sprеad into thе widеr сultural domain. It was' for instаnсе' signifiсantin thеoriеs сlf сhild dеvеlopmеnt,whеrе thе Arnеriсan psyсhologist аnd еduсationаlistG. Stanlеy Hirll aгguеd that сlrildrеn go through sеt stagеsсlf dеvеioprтеnt,and ir is pсlintlеssand сountегproduсtivе to tгy to fсlrсе tlrеrrlllеyond thеir iеvеI.Suсh idеas, pагtiсu]arly givеn that thеy wеrе firmly pr
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Rеcаpitиlаtion (and hе truly did think thеm mtlrе lrdvanсеd)in sonrеsеnsеrеvеаlirrgtlrеiгorigins through tlrеir еilЬrуolсlgv. Thеrе is sotrrсdеЬlrtеaЬсlut lvЬеtlrеr hе got this insight frоnr pеoplе dirесtly influеrrсесlЬу |хJаtur|lhilosophiе,сlr whеthеr hе was morе inсlinеd to a mсldifiес]vеrsiсll-tduе to thе Еstonian еmЬryologist Karl Еrnst von Baег. Although Baеr was nеvеr а full еvolutiоnist, hе arguеd that all organisms (within major grsof ;last and prеsеnt ftlrrns Ьut '"r.illnсlt nссеssаrill.shtlw similaritiеs with (аs thе Ьiogеnеtiсlaw сlaims) adult fсlrms of past organisms. (Howеvеr, it сompliсаtеs mattеrs thаt if past forms did ntlt dеvеlop muсh iгrontogеny' thеir adult forms would Ье likе tlrеir еmЬrytlniс fornrs llnd hеnсе likе tlrе еmЬryoniс forms of today.)It is pгoЬаЬlеthаt DaгrvitlgirtЬеrеdidеasfrtlпl аll sidеs,although hе wirs alwаys strongl1'.
аlrе.rdythеrе,
BIBLIOGRAP Agassiz,Е. С., еd. ] 8

Boston: HoLlghtс Agаssiz, L. 1859. Еs.s Longmans, аlrd I Bаеr' К. Е. von. [182 (Fragmеntsrеlаt K. Е. vor-rBаеr).trans. Lonсlon:T Саrroll, S. B' 200.5.Е апd tbе Маkiпg t D a r w i n , С . 1 8 5 9 .O и Gould, S. J. 1977.Ot Hаrvаrd L,Iпil,е Hаесkеl,Е. 1866.Cс Rеimеr. Наll, G. S. 1906. You Кnоll, A.' and S. B. С сompаrativе biсl R i с l r a r d s ,R . J . 1 9 9 2 . апd Idеrllоgiсаl I Сhiсago Рrеss. 2О03, Тbc Rс of Goеthе. Сhiса 2008. Tha Тr Еuo|иtiсlпаr1'Тht Rusе, М. 1996, N1t> СamЬridgе, МA: R u s s е l l 'Е . S . 1 9 l 6 . F с Мсlrphologу' Lor

Rеnsсh, Bеrnha

Bеrnhard Rеnsсlr w thе twеntiеth сеntur сiation, and maсro .lй7orld.JИar l during Anglo_Amегiсan mt with lеading еr,ol DoЬzhansky, JuIian of thе modеrn syr-r Bеrnhard Rеnsсh hild an еaгly intеrе еnt. Aftеr Woгld !

Reпsсh n somеsеnsеrеvеalingthеir oriаЬсlutwhеtlrеrhе got this .lеЬatе аturphilrlsophle,or whеthеr hе l thе ЕstoniаnеmЬrvologistKarl Il еvrllutionist. hе аrgrtеdthat аll n thе sеlrsе..arеrrrodеlеdon :rnd lasiс form Ьut thеn go thеir dif.еlopmеntwill shаrе similaritiеs r t w i I Ir r t l tn е с с s s . t г i sl yh o w s i m i : forms
alrеady thеrе, oftеn Ьv addiпg on to tllе еnd. But at timеs sеlесtionis going to if thеt,arе not nееdеdand еntirеly,еspесial11' rеmovе pегiods of dеvеlopn-rеnt (iшst animals in сavеs losе funсtioning еyеs).So as arе сostly to thе organism although rесapitr'rlationin its traditional form rvill nеvеr геturn, thе sorts оf issuеslvitЬ whiсh it dеalt arе onсе again Ьiologiсаlly rеspесtaЬlе' вlBLIoGRAPнY Agassiz'Е. С., еd. 1885./,oиl.sАgаssiz:His Lifе апd Сorrеspсlndепcе'2уo|s' Bоston:Houglrtоnl,tifflirr. London:Lсlngman,Brоwn,GLееtr, Agаssiz,L. 1859. Еssауoп Сlаssifiсаtiсltt. Lоngmans,and Rсlbеrts' dеr Thiеге Baеr,K. Е. vot"t. [182s-1s37]l8.53.UЬегЕnwiсkеlullgsgеsсhiсhtе (Frаgmеrrts rеlаtеdtсl Plriiсlsoplriсal Zоolog1,:Sеlесtеdfrсlmthе r'l.оrksoI Меmoirs,A. Неnfry and T. H. Huхlеy,есl.and K. Е. von Baеr).In Sсielttifiс trirns.London:Тaylor аnd Franсis. Сarroll, s. B. 200.5.ЕпdlеssForms Мrlst Bеаutiful:TЬe NеtuSсiспсеof Еutl Dcurl "tпd

thе Маhiпg

tlf t|lе Аltimаl

Kiпgtlсltlt. Nеrv \Ъrk: Nсlrton.

Dаrwitr, С. 18.59.Оп thе Origiп of Spегiсs. London: Jоhn Мurrаy. Goulсi, S. J. 1977. Опtсlgеп1,апd Phуlсlgепу.СаmЬridgе, МA: l3еlknapPrеss of Нагvаrd Univсгsity Prеss. Hаесkеl, Е. 1.ч66.(}cпеrеllе М<tphologiе dеr Оrgапistttеп. ) vo|s. Bеrlin: Gеorg Rеin.rеr. Hall, G. s. 1906. Youtb: Its Еdttсаtkлl, Rеgilпеп, апd Hуgiепе. Nеw York: Applеton. Knоll, А.' and S. B. Саrroll. 1999.Еarlу irnin.ralеvolution: Еmеrging viеws from ссlmpаrativе b io logy .rnс.lgеtliogr,.Sс i еltсе 28 4 : 2 129_21З 7 . Riсhards, R. J. |992. Тhс Меапillg сlf Еuсllпtiсlп: Thе Мor1lhсlktgiсаl Ссlttstruсtioп апd ldеologiса! Rессlпstruсtbп rlf Dаrtuiп's Тheorу. Сhiсago: Univеrsity of СЬiсago Prеss. 2О0З.Thе Roпшltiс Сопсaptirlп o|-I,ifс: Sсiеttcс апd PЬibsophт ilt thе Аgе of Goеthe' (ihiсago: Urrivеrsityof Сhiсago Prеss. 2О08. Thе Тrаgiс Sепsе of Lifе: Еrпst Hаесkеl апd thе Strttgglе oucr F-LtolиtiсlпаrуТhсlught. Сhiсago: Unir.еrsity of Chiсago Prеss. RLlsе, NI. |996. ]\4oпаdtсl Маrt: Тhc Сotrcapt оf Prtlgrеss iп Еuolutitlпаrv Biоltlgt,. СаmЬridgе' МA: Нarverd Univеrsity Prеss. Russе|l, Е. S. 1916. Рсlrm апсl Fttпсtiсlп:А Ссlпtribиtiotl tсl thс Нistorу r''fАпimаl М l l r 1 l h t i с l g у .L о l l d o r t : J rl l l l t M u r r а r . .

-М.R.

Rеnsсh.Bеrnhard(1900_1990) Bеrrrhаrd Rеrrsсh Was onе of thе lеirding cеrnrarr еvolutionary biсllogistsof thе twеntiеth сеntury. His сontriЬutiOnsto thе thеoriеsof Ьiogеogrzrphy,spесiation, and mасroеvolution, whiсh hе first synthеsizеdin rеlаtivе isolation during !Йorld War II' havr:Ьееn rесOglrizеdas tlrе Gеrman еquivalеIrtof thе Anglo_Amеriсiln modеrn synthеsis.Aftеr thе rvаr Rеnsсlr'sехtеnsivесontaсts with lеading еvolutiсlnaгy Ьiologists, suсh as Еrnst Мayr, Thеodosius DoЬzhansky, Juli;rn Huхlеy, and J. B. S. Haldаnе' сontriЬr.rtеdto tl-rеsprеad of thе modеrn synthеsisirr Gеrmаny. Bеrnhard Rеnsсh was Ьсlrn on January 27, |900, in Thalе, Gеrmany. Не had an еarly intеrеstirr nаturаl history, as wеll as an outstanding aгtistiс tal_ еnt. Attеr Wсlrld War I lrе studiеd Ьiologv, сhеtnistrr.,аrrd philtlsophy in

8з 1

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Rепsсh Наl1е, whеrе hе took his PhD tn 1922 with thе gеnеtiсistVаlеntin Haесkег, himsеlf a studеnt of August \rVеismann.His tеасhеr in philosоphy was Thеodor ZieЬen, who workеd primarily in epistеmologyand thе rеlationship Ьеtwееn physiсs, physiology, and psyсhology. Rеnsсh's intеrеstin еvolution soon lеd him to thе Musеum of Nаtural History in Bегlin' whеrе hе was put in сhargе of thе mollusk сollесtions. Нis sесond intеrеstwas in ornithology. Hе was in rhе right plaсе аt thе right timе ЬесausеBеrlin was onе of thе сеntеrsfor ornithology during thе 1920s, and Rеnsсh was in сlosе сontaсt with Ьoth Еrwin Strеsеmannand thе young Еrnst Mayr. |л 7927, as part of his musеum dr-rtiеsRеnsсh organizеd a zoologiсalanthropologiсal ехpеdition to thе Sunda Islаrnds.His ехpеriеnсеsin thе tropiсs ссlnfirmеdhis еarliеr idеas aЬout thе distriЬutiorrand еvolution of spесiеs and сontriЬutеd to his intеrеstin mасroеvolutionary proсеssеs.His first сontriЬution Was thе idеa of a Rаssепkrеls (litеrally a сirсlе of raсеs),a сonсеpt that unitеs suЬspесiеsаnd сlosеly rеlatеd spесiеs,whiсh gеographiсally rеplaсе еaсh othеr, into largеr сomplехеs. Rеlatеd to thе notion of Rаsseпkreis was Rеnsсh's idеa that gеtlgraphiс raсеs arе thе prесursors сrf nеw spесiеs. Studying thе distriЬution of spесiеs,Rеnsсh сould сonfirm sеvеral еvolutionary rulеs, Suсh as Bеrgmаnn's rulе' сorrеlating latitudе with Ьody sizе in animals (thе highеr thе latitudе, thе Ьiggеr thе animals), or Сopе's rulе, stating that linеagеstеnd to inсrеasеin sizе ovеr еvoluti<)nary timеs. Initially hе triеd to еxplain thеsе phеnomеna of parallеl еvolution (е.g.'animals in сoldеr сlimatеs tеnd to Ье lаrgеr) in nеo-Lamarсkiarrtеrms as сausеd Ьy dirесt influеnсе of thе еnvironmеnt on inhеritеd сharaсtеrs.Howеvеr' hе soon rеalizеd that all thеsе phеnomеna сan Ье ехplainеd Ьy thе aсtion of mutation, sеlесtion, and thе prinсiplеs of dеvеlopmеntal physiolсlgy, suсh as plеiotropiс gеnе aсtion сlr allomеtry. Rеnsсh dеvеlopеdhis own vеrsion of an еvolution.World ary synthеsis at thе еnd of lVar II. His Ьoоk Nеuеre Prсlblеmе der Аbstаmmuпgslеhrе was puЬlisЬеd in 1947 and was translatеd into Еnglish as Еuсllutiсlпаbouе thе Spесiesl-еuеl in 1959. Whеn it wаs possiЬlе for Rеnsсh to gеt aссеss to thе Anglo-Amегiсan litеraturе on еvolution, thе so-сallеd modеrn synthеsis' hе and еvеryЬody еlsе was struсk Ьy thе kind of intеllесtual parallеlism Ьеtwееnthеsе two synthеsеs'and today Rеnsсh is always inсludеd as onе of thе foundеrs of thе mсrdеrnsynthеsis. Latеr in his сarееr Rеnsсh dеvеlopеdhis own systеmof natural philosophy, whiсh was an outgrowth of his lifеlong work in еvolutionaryЬiology. His thеory had two mаin aspесts' a thеory of univеrsal dеtеrminism that inсludеd psyсhologiсal,сognitivе' and soсial phеnomеna,and his thеory of panpsyсhiс idеntism (Idеntismus). Thе lattеr aimеd to ехplain thе rеlationship Ьеtwееn mind and mattеr as thе rеSult of dеvеlopmеntaland еvolutionary Proсеssеs' whiсh for Rеnsсh ехplainеd all aspесtsof human and animal еxistеnсе. BIBLIOGRAPHY Hеbеrеr,G.' еd. 1943.Diс Еt,сllutillп dеr Оrgапismeп,Jелa GustavFisсhеr. Mayr, Е., and W' B' Provinе'еds. l980. Thе ЕuсllutiсlпаrуSупtbеsis:Pеrspесtiuеs oп thе Uпifiсаtiсltt tlf Biolrlgу,CanrЬridgе' МA: HarvатdUnivеrsityPrеss.

Rеnsсh,B. 1947.NеuеrеР 1959.Еuсllцtioпа Prеss.

Robеrtson, Alan (1

Alan RoЬеrtson Was DO d i е d i n Е d i n Ь u r g ho n A p [nstitutе, fоllowеd Ьy a B lеgе, СamЬridgе Univеr сhеmistry at СamЬridgе plеtе his PhD Ьесausе tl workеd in opеrational r .lfaddington joinеd in tht Gеnеtiсs Rеsеarсh orga Animal Gеnеtiсs) in Еdir Hе rесеivеd a DSс from animal genеtiсs and was RoЬеrtson's sеminal rt orеtiсal and appliеd ant p o p u l a t i o ng е n е t i с sa n d е stratеd thе thеorеtiсal t (Robеrtson and Rеndе сompaгison mеthodof 1 His thеorеtiсal work еx; sеlесtion rеsponsе(RoЬе f o r е s t i m a t i n gq u a n t i t а r to artifiсial sеleсtion.Rс е v a l u а t еt h е v a l i d i r уo f е thе theory nееdеd to bе sеrvеd and prеdiсtеdrеs nеtiс variatiоn. Hе an shoгt-tеrm rеsponsеsto l Ьut that long.tеrm rеspo сorrеlatеd traits (Сlayton paramеtеrs еstimatеd fr< prеdiсtions rеquirе knov of sеgrеgating allеlеs th; produсtivе fitnеss; as wеl tanеous mutations that а f i r s t е х p е г i m е n t st t l е s t traits and many ехpеriml ing on quantitativе tralt quantitativе gеnеtiсs dеp thе oЬsеrvеd variation. F f i г s t s t u d i е st o i d е n t i f y

Robеrtsсlп

thе gеnеtiсistValеntin Haесkеr, aсhегiп philosophy wаs Tlrеodor lgy аnd thе rеlationship Ьеtwееn h's intеrеstin еvolution soolr lеd эrlin,whеrе hе was put in сhargе St Was in ornithology. Hе was in lin lvаs onе of thе сеlltеrs for orrs in сlosе сontaсt lvith Ьoth ЕrRеnsсh organizеd a zoologiсal. Lnds.His ехpеriеnсеsin thе tropriЬution arrdеvolution of spесiеs utiсlnаrypr()сеssеs. Нis first ссrnrally a сirсlе of raсеs),a сonсеpt pесiеs,whiсlr gеographiсallу rеrtеd to thе nсltiono| Rаsseпkrеis е t h с p r е с u r s o r so f n е w s p е с i е s . сrluIdсonfiгrlrsеvеrаlеvolutionng latitudеrvith Ьody sizе in ania n i m a l s ) o, r С o p е ' s r u l е , s t a t i n g lIrrtiorrer1' tinrеs.Inirially hе triеd (е.g., ution animals in сoldеr сli' tеrms as сar"rsеdЬy dirесt influ_ сtеrs.Hotl,еvеr,hе soon rеalizеd Ьy thе асtion of mutation' sеlесphysiologу, suсh as plеiotгopiс his own vеrsiсlnof аrnеvolutions Ьook I'JeuеrеProblеme der Abd W а s t r а n s l a t е di n t o Е n g l i s h a s !7lrеn it wаs possiЬlе for Rеnsсh turе on еvolution, thе so-сallеd ls stгuсk Ьv tlrе kirrd of irrtеllес;, and today Rеnsсh is always insynthеsis' vl/nsystеп-lof naturerlphilosophy, in еvolutionaryЬiology. His thе/еrsaldеtеrminismthat inсludеd ln:1,and his thеory of panpsyсhiс эхplain thе rеlationship Ьеtwееn ntаl аnd еvolutionaгy proсеssеs' man and animal еxistеnсе.

smеп. lеna: Gustav Fisсhеr. |utiгlпаrу SJ,пt h е sis: Pеrsp есttuеs сlп H : t г rl r d U n i v е r s i t yP г е ь s .

Rеnsсh, B' 1947, Nеиerе Prrlblеlпе dar АbstапlmuпgslеЬrе. Stuttgart: Еnkе. 1959. Еuоluti<п аb
Prеss.

-М.D.L.

RoЬеrtson,Alan (\920_Т989) Alan RoЬеrtson Was Ьorn on FеЬrrrary 21,7920, in Prеston, Еngland' and diеd in ЕdinЬurgh on April 25 , |989 . His еarly еduсation wаs at tlrе Livеrpool Institutе,followеd Ьy a BA in сhеmistry in 1941 from Gonvillе and Caius Collеgе, Сarnbridgе Univеrsity. RoЬегtson's postgraduatе геsеarсh irr phуsiсal сhеmistry at CamЬridgе rеsultеd in sеvеrаl puЬliсations, Ьut hе did not сom.War plеtе his PhD Ьесausе of thе outbrеak of \Х/orld II. During thе war hе workеd in opеrational rеsеarсlr with С. H. IХ/аddington. Hе suЬsеquеrrtly 1oinеd.lt/addingtonin thе Agriсultural Rеsеarсh Сounсil Animal Bгееding and Gеnеtiсs Rеsеarсlr С)rganization (ABGRO) (suЬsеquеntlythе ARC Unit of Animal Gеnеtiсs) in Еdirrburgh, whеrе lrе rеmairrеd for thе rеst of his сarееr. Hе rесеivеda DSс from thе Univеrsity of ЕdinЬurgh in 19.51for his work on animal gеnеtiсsand was irppointеdan honoгarу profеssortn |967. RoЬегtson'ssеminal rеsеarсhсontriЬutions Wеrе in thrее major arеas:thеorеtiсal аnd appliеd animal Ьrеес1ing; thе gеnеtiсsof quantitativе traits; and populаtiorrgenеtiсsаnd еvolution (Нitt and Maсkаy 1989).RoЬеrtson dеmonstratеd thе thеoгеtiсal Ьеnеfits of prоgеny tеstir-rgin dairy сattlе Ьrееding (RoЬеrtson аnd Rеndеl 1950) and suggеstеd using thе сontеmporary. сomparison nlеthod of progеny tеsting to implеrnеnt it on a national lеvеl' His thеorеtiсal work ехp1оrеd thе еffесt of population struсturе on limits to sеlесtionгеsponsе(RoЬеrtson 1960)' as wеll as optimal ехpеrimеntal dеsigns for еstiпratingquantitarivеgеnеriсparаlr1еtеrs' inсluding сoгrеlatеdrеsPOпsеs tо artifiсial sеlесtion.RoЬеrtson also usеd Drosopbilа as а modеl systеm to еvаluatеtliе vаlidity of е-хistingquiпtitаtivе gеnеtiсthеory, to dеtеrn-rinе how thе thеory nееdеd to Ье еxtеndеd to сopе with disсrеpanсiеs Ьеtwееn oЬsеrvеd and prеdiсtеd rеsults,and to invеstigatеthе naturе of quantitativеgеnеtiс variation. Не аnd his с
8J.]

8 - 1 1 Romеr mоlесular markеrs in outЬrеd pсlpulations and for a largе-sсalе еffoгt to idеntify QTt,s in Drosophilа using a сomЬination of artifiсial sеlесtion,in. trogrеssion,and progеny tеsting (Shгimpton and RoЬеrtson 1988). In this rеgаrd RoЬеrtson is truly thе fathеr of r-ntldеrnmolесulirгqullntitаtivеgеnеtiсs. His many :rссomplishrnеntsWеrе honoгеd Ьy zrpрoinсmеnrto thе Ordеr of thе British Еmpirе in 1965; еlесtion as a fеllow of thе Royal Soсiеty of London in 1966 and оf ЕdinЬurgh in 1964; and еlесtion as a forеign assoсi. atе of thе National Aсadеmy of Sсiеnсеsof thе Unitеd Statеs of Amеriсa in 1979, a forеign lrоnorary mеmЬег of thе Gеnеtiсs Soсiеty of Japan, and a trrеmЬеrof thе SparrishRеal Aсadеmia dе Сiеnсiаs Vеtегinаriаs. BIBLIOGRAPHY Сlayton' G. A., G. R. Kпight,аnd А. RoЬеrtson.1957a,An ехpеrimеntal сhесk on quantitаtivеgеnеtiсalthеory.III.Сorrеlatеdrеspollsеs. .|oиrпаlof Gепеtiсs 55:171-180. С l а y t o n ,G . A . ' J . А . М o r r i s ,a n d A . R o Ь е r t s o n1. 9 . 5 7 ЬА.n е х p е r i m е n tсaЬl е с ko l r quantitаtivе gеnеtiсаlthеorу.I. shoГt-tеrm rеsponsеs to sеlесtion. Jourпаloi C епеtiсs.5.5:13 1_1.5,l . С l a y t o n ,G . A . ' а n d A . R o Ь е r t s o r r|.9 5 7 ,А n е х p е r i n r е n tсаhl е с kо n q u a n г i t . r г i v е gеnеtiсаlthеory.Il. Thе long-tеrmеffесtsof sеlесtion.|сlurпаlсlf Gепеtiсs 55: 152-170. Hill,.sи.G., and T. F' С. Мaсkay, еds.1989.Еuolutitlпаnd Апimаl Breеdiпg: Rеuiеtuson Мolесulаr апd Q'uапtitаtiuеАpproасbеsiп Hoпoиr of Аlап Robеrtson.Wаllingford'U.K.: С.A.B. Intеrnatiоnal. Robеrtsсlrr.A.1960.Athеorvof lirrritsiriагtifiсiаl sеlесtiorr. Proсееdingsсlf tllе Rrlуаl SoсiсtусlfLoпdoп, SеriеsB |53:234-249. RoЬеrtson,A.' аnd J. М. Rеndеl.19.50.Thе usеof progеnytеstingwith аrtiIiсiаl insеminatiоn in dairy сatt|е. l. lОиrпаlof Gепеtiсs.50:21_3 Shrimptоn,A. Е.' and A. RоЬеrtson.l988. Thе isolatiсlntlf polygеniсfaсtсlrs сontrollingbristlеsсorеin DroхlpЬilа mеlапogаstеr'2' DistriЬutionof third (}епetiсs11'8: сhromosomеЬгistlееffесtswithin сlrгomosomе seсtiсlns. 44545e. -T.l\t.

Romеr,Alfrеd Shеrwood(|s94_L973) Alfrеd Shеrwood Romеr Was an Amеriсan vеrtеЬratеpalеontologist and an еxpеrt on еarly rеptilеs. Hе produсеd sеvеral highly suссеssful tеxtЬooks агld sеrvеd as dirесtor of Hаrvard's Мusеum of Сorrrparativе Zoolog,v

(7946-196r).

Romеr was Ьorn in Nеw Еrrgland, and this сulturе dеfinеd his idеntity. Aftеr a diffiсult сhildhood Romеr еntеrеdAmhеrst Univеrsity in 1914, study.!Var ing Gеrman litеraturе and history. During thе Grеat hе voluntееrеd for thе Amеriсan Fiеld Sеrviсе and sеrvеd in thе U.S. Air Sеrviсе in Еuropе Ье. forе rеturning to thе Unitеd Statеsin 1979.He еntегеdСolumЬia Univеrsity to study vеrtеbratеpalеorrtol
In Сhiсago Ror-nеr с amphiЬians. working с ехtеnsivе ссlllесtionsof also wrotе gеnегаi tех апd the Vеrtеbrаtеs(19 еvolution to gеnеral au losophy. Fсlr spесialist in 1945 and 1966) сor сommеntary. Both Ьеса In Сhiсago palеonto sidеrеd lrirrrsеlfa Ьiolo сism of lris approaсh; l Univеrsity аnd thе Mus in this nеW sеtting.DuI mсldеrnizе.Hе sought 1 ing, and rесгltitес]to im ,l By lris rеtirеmеnrin 9 Aftеrwirrсl Rоmеr rеrl NovеmЬег l973 was L pеriod. Nеarly half his l R
ton еr.olvеd.Не аlso w. bonе, anс1thе nеrvous t in еvo1utionarylrist
Romer s аnd for a largе-sсalе

еffort to lination of artifiсial sеlесtion, irrr and RoЬеrtson 1988). In this rеr molесulаr quantitаtivе gеnеtiсs. by appointmеnt rO thе ordеr fеllow of thе Royаl

of

Soсiеty of

; and еlесtiоn as a forеign assoсif thе Unitеd Stаtеs of Amеriсa in Gеnеtiсs Soсiеty of Jаpаn, and a ]iеnсiаs Vеtеrinariаs.

^ l .1 9 5 7 a .A n е х p е r i п l е n t а сl h е с k itеd rеsponsеs.lottrtt,ll сlf Gепеtiсs 19.57b.An ехpегimеntаlсhесk or-r rеsponsеsto sе]есtiсln. .|спtrпаlrlf p е r i n r е n t асlh е с k о n q u a n t i t а г i v е I sе]есtiсln. .|rlttrпаlсlf Gепеtiсs 55 'olutiolt аlld АпimаI I|rеaJiпg: proасЬеs iп Hсlпtlпr оf Аlап rаtionаl. Lаlsеlесtiоn.Proсееdiпgs сlf thе l-249. сlf progеn1'rеsting witlr аr.ti1iсial e/lсs.i0:21_31. isсllаtiсln of pсllygеniсfaсtors nogаstеf.2. Distribution of third )mе sесtions.Cепеtiсs 118

-T.14.

)73) vеrtеЬratеpalеontologistand an еral lrighly suссеssful tеxtЬooks rsеum оf Сomparativе Zoo|ogу this сulturе dеfinеd his idеntity. mhеrstUnivеrsity ln |9\4, studyгhе Grеat lVar hе r,oluntееrеd for rе U.S. Air Sеrviсе in Еuropе ЬеHе еntегеdСolumЬia Univеrsity :d his doсtorаtе for work on thе rrd hе taught zoology at Bеllеvuе thе Univеrsity of Сhiсago to suсlratе pаlеontology'

In Сhiсago Rсlmеr сontinuеd his intеrеst in еarly (Pеrmian) rеptilеs and amphiЬians, wrlrking сlosеly with his prеparator' Pаul Millеr, and making еxtеnsivесoliесtions of tЬе Pеrmian ..rеd Ьеds'' in Tехils. In Chiсago Romеr also w,rotе gеnеrаl tеХtЬooks tlrat ехpеrtl1,summarizеd his fiеld. }Jis Мап апd thе Vеrtеbrаtеs(19ЗЗa) prеsеntеdсomparаtivе vеrtеЬratеаnatomy and еvсllutiсlnto gеllеral audiеnсеs.It also inсludеd Ьriеf hints of his soсial philosophy. For spесialists,VеrtеbrаtePаlеtпtoloеy (1933Ь, with lаtег еditions in l94.5 and 19$(1)ссlеrnizе. Hе sought Ьеttеr funding, triеd to rеvivе thе program of сollесting, гrndrесгuitеr.] to improvе thе сaliЬrе of thе musеtrn-r's staff and sttrdеnts. By his rеtirеmеnt in 196I tlrе MСZ lrаd rесtlvеrеdits first-сlаssrеputation. Aftеrward Rсlmеr rеturnеd to rеsеarсh and ехploгation. His dеath in NtlvеmЬеr 197З was unехpесtеd and саmе during his most aсtivе rеsеarсh pеriod. Nеarly hаlf his ЬiЬliogгаphy wаs ptrЬlishеdaftег his 65th Ьirthday. Rltlgvand gеology. For ехirmplе, in l940 lrе hеlpеd organizе thе Soсiеty
f-i.t

8З6

Romer вIвLIoGRAPHY СolЬеrt,Е. 1982'Alfrеd ShеrwoоdRorтеr(1894_]97З\'BiogrаphiсаlМеmoirsof thе Nаtioпаl Асаdеmуof Sсiепсеs5З 265_294. Romеr,A. 1933a.Мап апd thе Vеrtеbrаtеs. Сhiсagсl:Univеrsityof СhiсagoPrеss. 1933Ь.Vеrtеbrаtе Pаlеoпtoklg1'. Сhiсаgо:tJnivеrsitv оf СhiсagoPrеss.

-J.С.

s

Sсhmalhausеn,Ivz

Ivan Ivanoviсh Sсhma Ьiologists of thе twеn morphology undеr his later dеvеlopеdhis ow logiсal and еmЬryologi iсally, hе introduсеd th сonstanсy of phеnoty сonditions. StaЬilizing ization of phеnotypе Ьuffеrs organisms froг thе phеnotypiс еffесtsl hausеn's idеаs arе stil part of a Russian еqui inсrеasingly rесognizе Ivan Sсhmalhausеn 1884 into a family of doroviсh Sсhmalhаus foundеrs of Russiаnpa сusing mostly on thе sс thе Univеrsity оf Kiеv, Alеxеj Sеvеrtzov. Sсhп Sеvеrtzov whеn thе lаtt сomparаtivе anatomy hаusеn workеd Ьriеfly additionаl ехpеrimеnta iсal studiеs. Aftеr thе Sсhmalhausеn Ьriеfly l Voronеzh Ьеforе hе rеt hе was invitеd to Ьесoп Univеrsity arrd to hеa foundеd Ьy his tеaсhе awardеd thе ordеr of l gеt of thе politiсally ; Trofim Lysеnko. Likе Sсhmalhausеn lost his

-197з).tsiogrаphiсаl Меm
-J.С.

s Sсhmalhausеtl'Ivan Ivanoviсh (1884-|963) Ivаn Ivanoviсh Sсhmalhausеn Was onе of thе lеading Russian еvolutionlrry biologists of thе twеntiеth сеntury. Trainеd ilr thе tradition of еvolutionaгy moгplrology undег his mеntor Alехеj Sеvеrtzov (1866-19З6), Sсhmalhаusеn latеr dеvеlopеd his own vеrsion of еvtllutiorrагythеory tlrlrtrrrеrgеdmсlrpho_ logiсal and еmЬryсllogiсalсorrсеptswith sеleсtionistidеas arrdgеnеtiсs.Spесif_ iсally, hе introduсеd thе idеa of staЬilizingsеleсtionto aссount for thе rеlаtivе сonstanсy of phеnotypiс forms aсross a rangе of diffеrеnt еnvironmеntal сorrditions.StaЬilizing sеlесtion,as dеfinеd Ьy Sсhmalhаusеlr,lеads to сanаlization of plrеnotypеs as il сonsеquеnсе oi dеvеlopnrеrrtirlrеgulation that Ьцffеrs organisпrsfrom ехtегnаl аnd intеrn:rldisturЬanсеs,thus minimizing the phеnotypiс еffесts of gеnеtiс and еnvironmеntal variation. Today Sсhmalhausеn's idеas аге still widеly disсussеd,and thеir historiсal signifiсаnсе as part of a Russian еqr.livalеntof tlrе Anglo-Amегiсan modеrn synthеsisis also irrсrеasinglyrесognizеd. Ivan Sсhmailrausеnwas Ьсlгn in Kiеv (Ukгainе, thеn part of Russia) in 1884 into a family of Gеrmаn immigrants to Russia. His fathеr, Ivan Fеdoгtlviсh SсhmаlЬausеn'Was a profеssor of Ьotany in Kiеv аnd onе of thе fourrdегsof Russiаrr pаlеoЬorаny. Alrеady dшring lris sсhool уеi1rsIvan wаs foсusing mostly On thе sсiеnсеs'an еmphasishе сontinuеd from 1901 onw.rrd аt tlrе Univеrsity of Kiеv, studying еvolutionаry morphology undеr thе zoologist A I е х е jS е v е r t z o v S . с h m a l h а u s е rgrо t h i s f i г s r а p p с l i n t m е n at s а n a s s i s t а n tr o Sеvеrtzovwhеn thе lattеr movеd to Мosсow, whеrе hе wаs otfеrеd thе сhаir irr сompаrativе :ltlatomy. In I9I4, whilе rеsеilгсhing lris PhD tlrеsis, Sсl-rпiаl_ hirusеn wсlrkеd Ьriеflу at thе Stаzionе Zoologiсa di Napoli, whеrе hе lеarnеd аdditional ехpеrimеntal tесhniquеs that would furthеr ехpand his morphol
8.]8

Sсhmаlbаusеп dеаrrhin 1953 hе lvas graduаlly rеhaЬilitatеd,аnс] in 1955 hе Ьесan-rеthе lrеаd of thе епrЬrytrlogylaЬoratory at thе Zoologiсal Institutеin Lеningrad' whеrе hе workеd t>nhis nrajtlr r-nonographon tlrе origin of tеrrеstriаlvеrtеЬratеs,as wеll as sеvеrаlothеr projесts,еspесiallythе inсorporation ofсyЬеrnеtiс idеas into еvolutionary thеory. Sсhrnаlhаusеn Was also onе of thе rесipiеntsof thе D:rrwin Mеdal of tlrе I-еopoldinаiri Hallе, onе of thе oldеst Hе was h
ехaсtIy this еmphаsis prеsеnt-day еvоlutioг tory еvolution.

BlвLloGRAPH'

A d а m s ,М . B . 1 9 8 2 .S е syntlr еvolutionary Sуnthesis:Pеrspeс 114д. ц21yд1j

[-Iniv

Lеvit, G. S., U. Hossfеlс сyЬеrnеtiсs: Ivаn Iv progrаm for а svntl Ехpеrimепtаl ZсlсlI

89-r06.

S с h m a l h a u s еIn. ,l . l 9 4 I. Dordiсk' trаns.P СhiсagoРrеss'198 1,968.Thе Оrig AсаdеmiсPrеss.

Sсience аs сI Pfoс

Dаvid Hull, еmеritus jor philosophеrs of Ь quiry through his sеr апd His Сritics (197: attention on suсh qu and thе сharaсtеrоf е sсiеnсе. Не arguеd ti idеа that madе it pсls through organisms,d tinсtion bеtwееn rep (е.g.'gеnеs,lprеsегvе organisms) arе diffеr hiсlеs for rеpliсators tual aсцmеn of a rеп with dееp ехpеriеnсе Hull's major philo Accouпt of the Soсiа thе ground for a suсс сal саmps. on thе or that sсiеntifiсidеas hz flесtеd soсial powс.r .

othеr sidе Wеrе thе tесhniquеs of logiсаl ablе, knowlеdgе aЬo attеmptеd to саtсh s tional affiliations, ar

Sсiеnсе as a Proсеss

еd, and in 1955 hе bесamе thе oologiсal Institutеin Lеningrad, эn thе origin of tеrrеstrial vеrtе:ially thе inсorporation of сyЬеrlalhausеn was also onе of thе lldina in Нallе, onе of thе oldеst ).l9, forrr yеars Ьеforе his dеath m as thе foсal unit of еvolution. orphology, suсh as a сonсern for hе rеlаtionship Ьеtwееn ontogеs, and an еmphasison thе сorrеtogеnеtiс stagеs. Bесausе of his ny Sсhmalhausеnis oftеn sееn as vеlopmеntalЬiology (еvo-dеvo). ssiаntraditions of Ьiogеography сtеd in his usе of thе tеrm blolеmеntary struсtural unit of thе :mphasizеsthе intеgration of gе. сtors and thеir intеraсtions. It is еnosisand dеvelоpmеntalеvolurmous idеa, staЬilizingsеlесtion. iс and staЬilizing sеlесtiorr. Thе lvеr-сhangingеnvironmеntal (or lintаins сomplех adaptations Ьy сal prосеssеsof organisms. Thе his distinсtion is thе following: if aсt on еxisting variation within r an еvеr-сhangingеnvironmеnt, adaptationsсould еmеrgе in thе of сonstаntlyshifting fitnеssva1iumеsthat natural sеlесtion also I systеms of an oгganism, thosе аnism as a wholе, thеn onе сan е to thosе variants of thеsе sysгеrnaland intеrnal disturЬanсеs. r wili thus Ье maintainеd in thе еquеnсеof this form of staЬiliz.ill Ьесomеmorе саnаlizеd, that с o n s t r a i nt h е f u t u r ее x p r е s s i o n s zing sеlесtionwе thus sее an apogеny. Howеvеr, bесausе thеsе nal еvolutionaryfасtors, suсh аs :tionеmphasizеsthе importanсе еll as within Ьiogеoсеnosis.It is

ехaсtly this еmphasis on rеgulatory proсеssеs thаt сonnесts Sсhmаihausеn to prеsеnt-day еvolutionary dеvеlopmеntal Ьiology and thе сonсеpt of rеgulаtory еvolution. BIBLIOGRAPHY Adams, М. B. 1982. Sеvегtsсlvarrd Sсhmalhаusеn:Russiаn morphology and thе еvolutionary synthеsis. In Е. Мayr and \X/.B. Pтovinе, eds.,Tbе Еuolutiсlпаrу Sупthеsis: Pеrspесtiuеsсlп thе Uпifiсаtirlп of Biologу' 19З-228. СarтЬridgе, МA: Harvard Univеrsity Prеss. ..modеrn synthеsis',to Lеvit, G. S., U. Hossfеld, and L. Olsson. 2006. From thе сybеrnеtiсs:Ivan Ivаnoviсh Sсhmalhausеn(1884_1963) and his rеsеarсh program for a synthеsis of еvolutionary and dеvеlopmеntal Ьiolоgy. lourпаl of Ехpеrimеntаl Zсlologу' Pаrt B: Мolеculаr апd Dеuеlo1lmеntаl Еuolutiсlп 3О6B: 89-106. Sсhmalhausеn,|.|. 1949. Fаctors of Еuolutiсlп: The Thесlrу of Stаbiliziпg Sеlectiсlп. I. Dordiсk, trans. Philаdеlphia: Blakiston Сo. Rеprint' Сhiсago: Univеrsity of С h i с а g o P г е s s .l 9 8 6 . 1968 ' Тhе Оrigiп rlf Tеrrеstriаl Vеrtеbrаtеs. L. Kеlso, trrrns.Nеw Yоrk: -М.D'L' Aсadеmiс Prеss.

Sсienсe аs а Procеss (David Hull) David Hull, еmеritusprofеssor at Northwеstеrn Univеrsity, is onе of thе major philosophеrs of Ьiology writing today. Hе еstaЬlishеdwholе arеas of inquiry through his sеvеral influеntial Ьooks and many artiсlеs. F{is Dаrtuiп апd His Сritiсs (\973) aпd Philosrlphу nf Biologiсаl Sсieпсе (1'974)foсusеd attеntion on suсh quеstions as thе naturе of spесiеs, thе units of sеlесtion, and thе сharaсtеrof ехplanation in Ьiologiсal sсiеnсе,еspесiallyеvolutionary sсiеnсе.Hе arguеd tirеlеsslyfor thе сonсеption of spесiеsas individuals, an idеa that made it possiЬlе to think of sеlесtionat multiplе lеvеls, from gеnеs through organisms' dеmеs,and speсiеs.Hе introduсеd in a сlеar way thе distinсtion Ьеtwееn repliсаtors and iпterасtrlzs in sеlесtion thеory: rеpliсators (е.g.,gеnеs)prеsеrvеstruсturе through rеproduсtion, whilе intеraсtors (е.g., organisms) arе diffеrеntially affесtеd Ьy thеir еnvironmеnts and sеrvе as vеhiсlеs for rеpliсators.Hull Ьrought to his сonsidеrationsnot only thе intеllесtual aсumеn of a rеmarkaЬlе philosophеr Ьut thе sеnsitivitiеsof а biologist with dееp еxpеriеnсе, еspесially in systеmatiсs. Hull's major philosophiсal work, Sсiепсe аs а Proсess: Ап Еuolutioпаrу Асcollпt of thе Soсiаl аnd Сoпceptuаl Dеuеlopmеli сlf Sсiепсе (1988)' laid thе grоund for a suссеssful middlе way bеtwееn Ьittеrly opposеd philosophiсal сamps. On thе onе sidе Wеrе thе soсial сonstruсtionists'who suggеstеd that sсiеntifiсidеas had no purсhasе оn an indеpеndеntnaturе Ьut mеrеly rеflесtеd soсial powеr in thе сommunitiеs whеrе thеy wеrе produсеd; on thе othеr sidе wеrе thе logiсal еmpiriсists, who assumеd that thе wеll-honеd tесhniquеs of logiсal artiсulаtion and еmpiriсal invеstigation dеlivеrеd rеliaЬlе, knowlеdgе aЬout thе struсturе of naturе. |n Sciепсe аs а Prсlсess Fl:ul'| attеmptеd to сatсh sсiеntists at work, whеn thеir soсial positions, institutional affiliations' and pеrsonal antagonisms gavе shapе to thе idеas thеy

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Sсiеnсеаs a Proсеss advanсеd through thе usuаl instrunrеntalitiеsof sсiеnсе.Hull did not douЬt that knowlеdgе of thе wtlrld wаs aсhiеvaЬlе,Ьut lrе was сannily awarе of thе еvolution of that knowlеdgе against a variеgatеdеnvironmеnt of soсial relationships аnd naturirl dеtеrrrrinatеs. ,Sсiепcеаs а Proсess is a thrее-story Ьook. on thе grouпd floor liеs a talе of сontеst Ьеtwееn distinсt approaсhеs to systеmatiсsthat dеvеlopеd from t h е 1 9 6 0 s t h r o u g h t h е 1 9 8 0 s . D u r i n g t h i s p е r i o d t r a d i t i o n а l l уD a г w i n i a n е f forts to сOnstruсt phylogеnеtiс linеаgеs-Haесkеlian trееs trimmеd of unw:lrrantеd mеtaphysiсal assumptiсlns-Wеrе сhallеngеd Ьoth Ьy thе nеw numеriсal tаxonоnrists,or phеnеtiсists,as thеy Ьесan-re knowt-l,and Ьy thе rigroup val of сIadistiс phylogеnеtiсists.Thе numеriсal taХOnomists,who dе. vеlоpеd thеir idеas initially at thе Urrivеrsityof Kansas, maintаinеd th:rttraits of organisms should Ье givеn еqual weight and numеriсally assеssеdthrough artfully dеsignеd сomputеr algorithms. Сlustеrs of similаrity would Ье thе modе of groLrpingorgarrismstogеthеrinto tаxonomiс сatеgoriеs.Thе сladists, who gathеrеd at thе Amеriсan Musеum of Natuгаl History in Nеw York, wеrе inspirеd Ьy thе idеas of an oЬsсurе Еast Gеrmаn еntomologist,!7illi Hеrrnig. Thеy соntеrrdedth:rtphylogеnеtiсrеlatiоnships (of a vеrv trurrсatеd sort) сould Ье еstaЬlishеdЬy arranging org:-rnisms into diсhсltomoustaхa on thе Ьasis of sharеd sеts of traits dеrivеd fтom a сommon anсеstor.This modе of аnalysis w
сlеs, Ьooks, lесturеs,ar-rd oгiеs, proЬlеms, and аpp vanсеs in thе sсiеnсes.In < onе of thе lеadеrs of thе r в|вLIoGRAPнY

Hull, D. 1973,Dаrшiltапd Еuolutiottbу thеSсiепt Prеss. 1974.Philosoph1'с | 9 8 8 .S с i c п с еа s а Р СoпсеptuаIDеUеlopm

Sсiеntifiссrеationlsn

Тhе tеrm sсiсntifiс сrсаti, into tlsе in thе еarly 197 gеology sanitizеd thеir B гooms.ln l970 а сrеаtion Sсiеnсе Rеsеarсh Сеntег l Цp an еnginееringprofеs сoursе titlеd Sсiеnti{iс Сr сrеirtionist lеadеrsWеrеu thе laЬеl of сhoiсе for th with сollеaguеsat thе СS whiсh Ьесamе thе huЬ oi A 1 9 8 1 A r k a n s a sl a w t ati
tion of thе еаrth's gеolo woгldwidе flood; and (6) kinds'' (Aсt 590 of 198

Whаt most distinguishе tion wаs thе fifth artiс idеntifiеd Noah's flood z tionist and сrеаtionistсo During thе first hаrlf .

had split ovеr thrее intе t h а t r h е f i г s гс Ь а p t е rt l f t ginning,'' at somе unspе 6,0O0 yеars ago, whеrrG dа1,-,1', thеorу' whiсh е

Scientifiс Сrеаtiсlпism itiеsоf sсiеnсе.Hull did not douЬt 'lе, but hе was сannily awarе of thе iеgatеdеnvironmеnt of soсial rеlaэk. on thе ground floor liеs a talе ) systеmatiсs that dеvеlopеd from pеriod traditionally Darwinian еf-Haесkеlian trееs trimmеd of unrеrе сhallеngеd Ьoth by thе nеw thеy Ьесamе known' and Ьy thе riе numеriсal taxonomists, who dе:y of Kansas, maintainеd that traits : and numеriсally assеssеdthrough lustеrs of similarity would Ье thе taхonomiс сatеgoriеs.Thе сladists, of Natural Нistory in Nеw York, .vиilli Еast Gеrman еntomologist, : rеlationships(of a vеry trunсatеd 3anismsinto diсhotomous taХa on )m a сommon anсеstor.This modе group pairings that сould Ье dеphiс dеviсе.Nеithеr thе tесhniquе al or morphologiсal rеsеmЬlanсе) .еlopmеntalhistory of spесiеs,and dеfiсiеnt Ьy thе morе traditionаl impsоn and Еrnst Мayr. Thе phemеnt by сharging traditional sysll himsеif admittеd his prеfеrеnсе сount of proposеd systеmatiс rеlats of a history of thе gеnеral forpеriod during whiсh thе systеmaHull portrayеd thе main fеaturеs uсh as Riсhard Lеwontin, Stеphеn d o. !7ilson Ьеgan rеshaping thе ls, Hull sеrvеd as an еditor of thе lf whiсh Ьattlеs Ьеtwееn thе waris allowеd him to follow thе stгuglity, for ехamplе, in thе rеfеreеing ld of ехpеriеnсе, hе сonstruсtеd a hе proposеd an еvolutionary thе[t was а powеrful framеwork that nismsof сoopеration and сompеtlt of spесiеsЬut of knowlеdgе. Hе .ologismsof intеraсtors (е.g.,arti-

сlеs,Ьooks, lесturеs,and Ьrains of sсiеntists)and rеpliсators (е.g.,idеas' thеoriеs, proЬlеms, and approaсhеs) to givе a сompеlling aссount of rеal advanсеs in thе sсiеnсеs.In offеring his thеory of sсiеntifiс growth' Hull Ьесamе onе of thе lеadеrsof thе nеw group of еvolutionary еpistеmologists. в|вLIoGRAPHY Hull' D. 197З. Dаrшiп апd His Сritiсs:Thе Rесеptiсlпof Dаrtuiп'sТhеorу of Еuolutioпbу thе Sсiепti|iсСommипitу.СamЬridgе,МA: Нarvаrd Univеrsity Pгеss. 1974, Philсlsсlphусlf BiolсlgiсаlSсiепсе.ЕnglеwoodСliffs, NJ: Prеntiсе-Hall. 1988.Sсiепсеаs а Proсеss:Aп ЕuolutioпаrуАcссluпtof thе Soсiаl аnd СonсеfltиаlDеuеklpmепtсlf Sсiепсе.СЬiсagсl:Univеrsityof Сhiсago Prеss. -R./.R.

Sсiеntifiссrеationism Thе tеrm scieпtifiс crесltio?Iism,аnd its synonym' сrеаtioп sciепсе, first сamе into usе in thе еarly 1970s, whеn advoсatеs of what had Ьееn сallеd flood gеology sanitizеd thеiг BiЬlе-Ьasеd viеws to gеt thеm into Amеriсаn сlassrooms. |n 1970 a сrеationist group in southеrn Саlifornia formеd thе СrеationSсiеnсеRеsеarсh Сеntеr (сSRс). That fall Hеnry M. Morris, who hаd givеn up an еnginееringprofеssorshipat Virginia Tесh to join thе сеntеr' offеrеd a сoursе titlеd Sсiеntifiс Сrеationism. By thе spring of 1972 Мorris and othеr ..sсiеntifiссrеationism'' as сrеationistlеadеrswеrе urging followеrs to adopt thе laЬеl of сhoiсе for thеir antiеvolutionary agеnda. That yеar Morris split with сollеaguеsat thе сsRС and sеt up thе Institutеfor Сrеation Rеsеarсh, whiсh Ьесamе thе huЬ of sсiеntifiссrеationism. A 1981 Arkansas law that mandatеd ..Ьalanсеdtrеatmеnt'' in tеaсhingсrе. ..(1) Suddеn сrеation of thе аtiсln and еvolution dеfinеd сrеation sсiеnсе as univеrsе, еnеrgy' and lifе frоm nothing; (2) Thе insuffiсiеnсy of mutation and nаtural sеlесtionin Ьгinging aЬout dеvеlopmеntof all living kinds from a srnglе organism; (3) Changеs only within fiхеd limits of originally сrеatеd kinds of plants аnd animals; (4) Sеparatеanсеstгy for man and apеs; (5) Ехplanation of thе еarth's gеology Ьy сatastrophism, inсluding thе oссurrеnсе of a worldwidе flood; and (6) A rеlativеly rесеnt inсеption of thе еarth and living kinds'' (Aсt 590 of 1981, Gеnеral AssеmЬly, State of Arkansas, sесtion 4). !7hat most distinguishеd сrеation sсiеnсе fгom othеr altеrnativеs to еvolution was thе fifth artiсlе' еspousing сatastrophism. Sсiеntifiс сrеationists idеntifiеd Noah's flood аs ..thе rеal сrux of thе сonfliсt Ьеtwееn thе еvolutionist and сrеationistсosmologiеs'' (Мorris et a|. 1974,252|. During thе first half of thе twеntiеth сеntury Сhristian fundamеntalists had split ovеr thrее intеrprеtаtionsof Gеnеsis 1: thе gаp theorу, whiсh hеld ..in that thе first сhaptеr of Gеnеsis dеsсriЬеdtwo сrеations,thе first thе Ьеginning,'' at somе unspесifiеd timе in thе distant past, and thе sесond aЬout 6,000 yеars ago, whеn God сrеatеdAdam and Еvе in thе Gardеn of Еdеn; thе ..days'' dау-аge theorу, whiсh еquatеd thе of Gеnеsis 1 with vast gеologiсal

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Sсiеntifiс Сreаtiontsm agеs; and the flood-gеologу tbeorу, whiсh allowеd for no lifе on еarth Ьеforе thе Еdеniс сrеаtion and аssignеdmost of thе fossil.Ьеaringroсks to thе сatastrophiс work of thе ЬiЬliсal Dеlugе. Until thе 1960s thе vast majority of Сhristiаn antiеvolutionistswho lеft a rесord of thеir viеws on Gеnеsis еmЬraсеd еithеr thе gap or day-agе sсhеmеs,whiсh pеrmittеd thе aссеptanсеof thе fossil еvidеnсеfor an old еarth. Thе young-еarthflood gеologists'in сon. trast' сomprеssеd virtually thе еntirе gеologiсal сolumn intсl thе yеar of thе Flood. F.lоod gеology was thе invеntion сrfGеorgе MсСrеady Priсе (1870-|96З), a sсiеntifiсally sеlf-taught Sеvеnth-day Advеntist tеaсhеr from еastеrn Сanada (sее figurе). As an Advеntist Priсе aссеptеd thе authority of thе prophеtеss Еllеn G. lff/hitе,who during onе of hеr tranсеlikе visions сlaimеd to havе witnеssеd thе Сrеation, whiсh сlссurrеd in a litеral wееk. Shе also taught that Noah's flood had sсulptеd thе surfaсе of thе еarth, Ьurying thе plants and animals found in thе fossil rесord, and that thе Сhristian SаЬЬath should Ье сеl. еЬratеd on Saturday rathеr than Sunday' as a mеmorial of a siх-day сrеation. Shortly aftеr thе turn of thе сеntury Рriсе dеdiсatеd his lifе to a sсiеntifiс dеfеnsе of lfhitе's vеrsion of еarth history, duЬЬеd thе ..sсiеnсеof сrеationism'' Ьy onе of Priсе's disсiplеs (Harold Сlark in Bасk to Сreаtiсlпism, 1929, 12-6_1з9).Although Priсе was widеly laudеd in antiеvolutionistсirсlеs, fеw non-Advеntist сrеationistsЬеforе midсеntury adoptеd his pесuliar intеrprеtat i o n o f G е n е s i s1 . For flood gеologists,thе sizе of Noah's ark Ьесаmеa major сonсеrn. Givеn its limitеd сapaсity' it сould not havе housеd rеprеsеntativеsof all thе аnimаl spесiеsthat zoologists had idеntifiеd.Thus in oгdеr to avoid making thе ark ..morе сrowdеd than a sardinе сan,'' flood gеologists typiсally pullеd Ьaсk frоm dеfеndingthе spесial сrеation of spесiеsto insisting on thе divinе origin of thе Еdеniс kiпds (|etterfronr D. J. \Х/hitnеyto B. С. Nеlson, Junе 18, 1928, in Nеlson Papеrs, propеrty of Paul Nеlson, quoted in NumЬеrs 2006, I27). Thе nееd to havе spесiеs еvolvе rapidly from thе kinds savеd on thе ark (whiсh сamе to Ье known as miсroеvolution) pushеd thе young-еarth сrеationists to grasp ..еvеry Ьit of mсldifiсаtiotr dиriпg desсепt that сan rеasonably bе assеrtеd''(lеttеrfrom D. J. Whitnеy to B. С. Nеlson' Junе З, 1928, in Nеlson Papеrs, propеrty of Paul Nеlson, quotеd in NumЬеrs 2006, |27). Thе popularity of flood gеolсlgyrosе dramatiсally with thе puЬliсation in .sfhitсomЬ 1967 of Tbе Geпesis Flood Ьу Мorris and John С. Jr. Unlikе Priсе, who at timеs allowеd for thе prеsеnсеof а lifеlеss еarth Ьеforе Еdеn, .WhitсomЬ Мorris and limitеd thе agе of thе еntirе univеrsе to no morе than 10,000 yеars and arguеd that somе physiсal laws, suсh as thе sесond |aw of thеrmodynamiсs, did not еxist until Adam and Еvе sinnеd. |n 196З Мorris joinеd ninе othеr sсiеntifiсally trainеd сrеationists to form thе Сrе. ation Rеsеarсh Soсiеty, an organization сommittеd to thе propagation of flood gеology. Thе high tidе of sсiеntifiссrеationism сamе in thе еarly 1980s whеn Arkansas and Louisiаna passеd lаws that mandаtеd thе tеaсhing of сrеation sсiеnсе whеnеvеr еvolution was taught. In 1987, howеvеr, thе U.S. Suprеmе Сourt

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Sсiеti ifiс Сrеаti t'пism 'llоwеd for no lifе on еarth Ьеforе 'е fossil.Ьеaringroсks to thе сatal thе 1960s thе vast mаjoriry of гd of thеir viеws on Genеsis еm',hiсh pеrmittеd thе aссеptanсе of Ing-еarthflood gеologists, in сongiсal сolLrmninto thе yеar of thе gе iVIсСгеadyPriсе (187О_1963)' ntisttеaсhеrfrom еаstегnСanada l thе authority of thе prophеtеss :еlikеvisions сlaimеd to havе wititеral wееk. Shе also taught that еarth,Ьurying thе plants and an: Сhristi:rrrSаЬЬath should Ье сеll l m е l n o r i a lo f a s i х - d a 1с r с a t i o n . еdiсаtеdhis lifе to a sсiеntifiс dеэЬеdthе ..sсiеnсеof сrеationism'' in Bаch tсl Сrеаtioпism, 1929, эd in antiеvolutionistсirсlеs, fеw y a d o p t е dh i s p е с u l i а ri n t е г p г е t a k bесamеa major сonсеrn. Givеn l rеprеsеntativеs of аll thе animal in ordеr to avoid making thе ark gеologiststypiсally pullеd Ьaсk ' s r o i n s i s t i n go n t h е d i v i n е o r i g i n y t o B . С . N e l s o n 'J u n е 1 8 , 1 9 ? 8 , quotеd irr Nr.rmЬеrs2006' 12.7|. .om thе kinds savеd on thе ark эn) pushеd thе young-еaгth сrеt duriпg dеsсeпt that сan rеasonto B. С. Nеlson, Junе 3, 1928, in эtеd in NumЬеrs 2006,127). тatiсally with thе puЬliсation in J Jоhn С. WlritсomЬ Jr. Unlikе е of il lifеlеssеarth Ьеforе Еdеn, thе еntirе univеrsе to no morе hysiсаl laws, suсh as thе sесond Adam and Еvе sinnеd. In 796З еd сrеationiststo form thе Сrеlmmittеd to thе proрagation of irl thееarly 1980swhеn Aгkansas t h е t е а с h i n go f с r е a t i o n s с i е n с е )wеvег'thе U.S. Suprеmе Court

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Supеrfiсiallythis piсturе,Ьy GеorgеNlсСrеаdy Priсе, looks vеrу muсh likе thе p i с t u r е o fl i f е ' s h i s t o r y g i v е jnu s t a f t е r t h еО r i g i n b y R i с h a r d ( ) w е n ( s е е F i g u r е 14 in thе main еssay..ThеHistory of ЕvoIutionaryThought'' by Miсhaеl Rusе in this volumе).Tlrе Darwiniаns аnd Ьy thеn almost сеrtаinlyOlvеn himsеlf took thе соlumn to Ье еvidеrrсеof еvoIutiсln'somеthingthаt hаd tzrkеnplaсе ovеr millions of yеirrs.Tо thе сontrary' Priсе sirrvthis аs еvidеnсеof Noah's сlimЬing тtl thе ttlps of hills Ьсforеthе,v flood, with thе mсlгеnimЬlе oгgi-tl-list-lls wеrе drownесl.(Fгom Priсе 1925.)

841

Sсopеs Тriаl rulеd that Suсh laws violatеd thе First Amеndmеnt to tlrе Сonstitution, whiсh rеquirеs tlrе sеpаratiorrоf сhr'rrсlrаnd stаtе.Dеspitе this sеtЬасk сrеation sсiеntists flourishеd to thе point thаt thеy virtually сo-optеd thе tегm сrеаt|o|Iism for thе formеrly marginal idеаs of Priсе. .sИhеrr Intеlligеnt Dеsign (ID) Thеory appеarеd in thе 1990s as a morе есumеniсаl option for antiеv
thrее-timе prеsidеntial са thе rr
аn еnd. T h е Ь а с k g г t ) u n dt ( )t h i l inсеndiary wгitings сlf B. ninеtееnth сеntury. Aftеr movеd quiсkly to fill thе a n d с u s t o п l s 'T h i s w a s а guidanсе aЬollt m()ral an а n \ t h i n g t o l . ' еf o u n J i n n а t i o n t h е o l o g i с t l l l ya, s u

вlвLloGRAPl.{Y Сlark, Н. w. |929. Bасk tсl Сrеаtioпism, Anglvin,СA: PaсifiсUnion СollеgеPrеss. Сolеman,S., and L. Сarlin, еds.2004. Thе Сultиrеsсlf Сrеаtioпism:Апtiеurllutioпismiп Епglish-Spеаkiпg Сoипtrlсs.Aldеrshot,U.K.: Ashgatе. Hааs,J. W., Jr. 1997. Оn intеlligеrrt dеsign,irrсduсiЬlесоmplехity'аnd thеistiс sсiеnсе.Pеrspcсtiuеs oп Sсiсttсеапd СhristiапFаith 49 (Мarсh):1. Lаrson, Е. J. 2003. 7-riаlапd Еrrtt: Thе Аmеriсап Сoпtrсluеrsуouеr Сrе.ttioпапd Еuolutioп.3rdеd. Nеw Yоrk: Oхford UnivеrsityPrеss. Morris, H. М., еt aI,|974. SсiепtifiсСrеаti
-R.L.N.

Sсopеstrial |n 1925, in Daytсln, Tеnnеssее,i.rftеrthе p2tssagеof а statе law thzrtЬannеd thе praсtiсе of tеaсhing еvolutiOn' a yollng Ьigh.sсlrooltеaсhеr,John Thomаs Sсopеs,Was put on trial for violating thе prohiЬition. Hе Was prоsесutеdЬy

Thе whtllе disputе ovеr е\ сlffеrеd so mаlr\. oрPorttlr havе соnсlutlеd сtlllесtivе from Brvan 1924.)

Scopes Triаl lmеnt to thе Сonstitution, whiсh Dеspitеthis sеtЬaсk сrеation sсiralIyсo-optеd thе tеrm сrеаtioпpеarеdin thе 1990s as a morе utionist сritiсs attеmptеd to dis. f u I I y ' . . r h sеa m е o l d с г е a r i o n i s t |96,5). Сrеation sсiеntiststhеm, faultеd ID аdvoсatеs for thеir iсripturеаnd thе сonstruсtion of е long pеriod of yеars'' (Haas st сеntury' though failing to disshowеd tЬar 45"lo of Amегiсans .еtty muсh in thеir prеsеnt form o.'' Fifty-sеvеn pеrсеnt said that n (NumЬеrs 20О6, 1)' Contrary эnism had Ьеgun to attraсt folg non-Сhristians.A сеntury and эеliеvеrs.

thrее-timеprеsidеntial саndidatе Williаm Jеnnings Bryan and dеfеndеd Ьy thе notеd lawyеr Сlаrеnсе Dаrr
, СA: PaсifiсUnion Сollеgе Prеss. ,еsof Сrеаtiс-lпism: АпtiA l d е г s h o tU' . K . :A s h g а t е . r с i b l ес с l m p | е х i tayn. d r h е i s t i с l Fаith49 (Мarсh):1. t Сrlntrouеrsуouеr Сreаtioп апd sity Prеss. SanDiеgo,СA: Crеation-Lifе .iса.СamЬridgе,MА: Нarvard rеаtionismto IпtеlligeпtDеsigп. .еrsityPrеss. Nashvillе,ТN: Southеrn klпistsiп а Sесulаr V/orld. Nеw ^ |а, Uсslgn l / (sprlng'): ). е CеnеsisFlood: Tbе Bibliсаl

эlphia: PrеsЬytеrian and тн.Til

sagеof a statе law that Ьannеd 1h-sсhooltеaсhеr,John Thomas hiЬition. Hе was prosесutеd Ьy

чJl}\}(Fк\s

Thе wholе disputе ovеr еvolution and thс thrсat it ptlsеd to biЬliсаl litеralism offеrеd so Iтаny oppоrtunitiеs to саrtoonists of аll pеrsuasiсlnsthat thеy must hаvе сonсludеd соllесtivеly thаt thеrе rеzrllyis а Ьеnеvolеnt God! (By Е. J. Paсе; from Bryan 1924.)

845

846

Sсopеs Тriаl takеn litеrally supports slavегy. Tlris wаs a majtlr rеason why, in thе North aftеr thе сonfliсt, inсrеasingly thе aссounts in thе BiЬlе, еspесiaIlythе Gеnе. sis storiеs of Сrеаtion' Wеrе intеrprеtеd in a mеtaphoriсal or allеgoriсal fashion. In thе South' howеvеr, and in thе \й/еstаs pесlplеmtlvеd Out aсross thе Grеat Plаins, thе BiЬlе, if anything, took on aсldеdimportаnсе, and taking it litеrally was lеss a mattеr сlf thеology and mtlrе of rеgional pridе. Inflamеd Ьy thе tеасhing of сharismаtiс еvangеlists, notaЬly Dwight L. Мoody-..I look upon this world as a wrесkеd vеssеl. G
shortly aftеr thе trial. In sеlf wеll on thе witnеss thе litеralists wеrе now parеd to aссеpt that thе s Morеovеr, although е Dayton thеy had shown thе South wеrе, in mar

l a u g h . S с h o o l - r е х t Ь o o k1 knowing how сontrovеr guttеd thеir warеs of an; a f Г a i г sp е r s i s t е dt h r o u g h nik, Amеriсan sсiеnсе ( govеrnmеnt-sponsorеd :

Naturally this aggravat round of quarrеling ovе вlBLloGRAPHY

Anonymоus. 1'925' Тhе \\ Саsе. А Wсlrd-fсlr-\V АntiЕuolutioп Аct, t1 апd Аrgumеntsof thе Lаst Speесh.Сinсinn .W.. Bryаn, I. \924. Sеuеп( Nеw York: FlеmingI 'W Daniеls, ' H. 1877.Мсlс and Phillips. H u n t е rG , . l9l4. A Сiuiс Book Сompany. Larson,Е. J. 1'997.Summ СontiпuiпgDеbаtеol Rusе,M. 20О5.Тhе ЕuoI UnivеrsityPrеss.

Sееdplants

T h е е v o l u t i o no f s е е dJ а n d s е е d s ,i s а r е m а r k a t h е с а s е o f f l о w е r i n gp | of growth forms that rn Sееd plants inсludе Thе gymnospеrmsсom еnсlosеd in а prorесttv aЬout 900 spесiеst-'ftr genвs Еphedrа' from.'u othеr groups). Thеsе al nаnt gгoup of land plar thе rеmaining gymnos othеr gymnospеrmsaг(

Sеed Plапts major геason why, in thе North in thе BiЬlе, еspесially thе Gеnеn a mеtaphoriсal or allеgoriсal йi'еstas pеoplе movеd out aсross
shortly aftеr thе triаl. In faсt' gеnеral opinion Was that Bryan aсquittеd himsеlf wеll on thе witnеss stand. Hе was сеrtainly no Ьlind fundаmеntalist,as thе litеralists wеrе now сallеd. Hе admittеd that hе himsеlf wаs quitе prеparеd to aссеpt that thе siх days of сrеation wеrе siх vеry long pеriods of timе. Morеovеr, although еvolutionists rathеr сongratulatеd thеmsеlvеsthat in Dayton thеy had shown how сrudе and simplistiс the litеralist Сhristians of thе South wеrе, in mаny rеspесts it was thеsе litеralists who had thе last laugh. Sсhool-tехtЬookpuЬlishеrsalways put profits ahеad of prinсiplеs, аnd knowing how сontrovеrsial thе tеaсhing of еvolution had now Ьесomе, thеy guttеdthеir warеs of any disсussionwhatsoеvеr aЬout thе topiс. This statе of affairs pеrsistеdthrough thе 1950s until, aftеr thе Russian suссеsswith Sputnik, Amеriсan sсiеnсе еduсation gеnеrally was upgradеd (mainly through govеrnmеnt-sponsorеdnеw tехts)' and this upgrаding inсludеd еvolution. Naturally this aggravatеd litеralists' and so thе nation Was sеt for anothег round of quarrеling ovеr sсiеnсеand rеligion, whiсh Wе still livе with today. в|BLIoGRAPHY ,Wсlrld's Еuolиtkп Мost FаmrэusСoиrt Triаl: Tеппеssее Anonymous.|925. Тhе -Геst сlf thе Tеппеssее Сourt Rеport с-lfthе Fаtп
Sееdplants Thе еvolution of sееd plаnts, thosе plants with protеin-сoatеdpollеn grаins and sееds,is a rеmarkaЬlе сhroniсlе
817

848

Sеed Plапts rеsult, lеss familiar. Thе gymnсlsPеrms havе sеparatе malе аnd fеmalе rеproduсtivе organsJ usually on thе sаmе individual (сal[еd monoесy), although somе spесiеs lrаvе individuals that arе еithеr сomplеtеly malе or fеrnalе (саllеd dioесy). Роl[еn is usua1lytг:rnsportеdto stigmаs Ьy wind. Thе angiospеrms)Or florvеring plants, inсludе all plants whosе sееds аrе еnсlosеd in a protесtivе struсtuГе' likе a fruit, fornrеd from thе tissuеs of thе fеmalе ovaгy (сallеd thе саrpеl). Thеrе arе ovеr 350,000 ехisting spесiеsof angiоspеrms'and thеy display a dezz\ingdivеrsity of growth forms, inсluding tiny, floating aquatiс plants likе duсkwееd, familiar hеrЬs likе liliеs аnd irisеs' shrubs likе ЬluеЬеrriеs,giant trееssuсh as oaks, vinеs, and еvеn a widе variеty of parirsitеsof otlrег plants likе lndiar-rpipеs. Flowеring plirnts havе nеarly еvеry Ьrееding systеm inlaginаЬlе;thе mаjority of spесiеshavе pеrfесt flowеrs (malе аnd fеmalе oгgans in thе samе flowеr), Ьut thеrе arе quitе a fеw spесiеswith monoесy' somе with dioесy, and othеr spесiеsin whiсh somе individuals havе pеrfесt flowеrs аnd othеrs havе flowеrs сlf only onе gеndеr. Although most spесiеsarе сross-pollirratеd,somе arе sеlf-fеrtilizing,and othеrs usе a miхсttге of normаl сross_pollination and еitl-rеrsеlf-fеrtilizatiсlnor сlonal rеproduсtion. Thе mаjority of flowеring plants arе pollinatеd Ьy insесts,Ьut a signifiсant numЬеr of spесiеsarе pollinаtеd Ьy othеr animals, еspесially Ьirds and Ьаts, and many spесiеs dispеrsе thеir pollеn Ьy wind (еspесiallygrаssеsand sеdgеs).Sonrе aquatiс plants аrе Watеr pollinatеd, and sеvеral arе pоllinаtеd Ьy rodеnts. Angiospеrms аnd somе of thе gymnospеrms hаvе ;r rеrnarkaЬlеrеpгoduсtivе systеmthirt involvеs a doublе fепilizatiоn. Pollеn sporеsсarry two гruсlеi, еaсh of whiсЬ саrriеs a haploid сomplеmеnt of gеnеs(a сomplеmеntwith half thе gеnеs nесеssary foг thе wholе organism). Onе nuсlеus fеrtilizеs thе fеmalе ovulе, whiсh has a haploid сomplеmеnt of its own' to form thе еmЬryo. Thе othеr nuсlеus fusеs with othеr сеlls assoсiatеd with thе сlvr-rlе to form an orgаn саllеd thе еndospеrm, whiсh hеlps providе nutrition to thе dеvеlоping еmЬryo. This proсеss is wеll dеsсriЬеd in thе major irlrgitrspегmgroups Ьut rе. mains poorl1, undеrstood in sorlrе аngiospеrms and most gymnospеrms in whiсh it has Ьееn oЬsеrvеd.DouЬlе fеrtilizationis a dгamаtiс rеproduсtivеin' novation' and undеrstanding how it сrссurs,and whеthеr it oссurs in thе samе fashion in gymnospеrms and angiospеrms (not to mеnrion whеthеr it oссurs in all spесiеs),lvould providе сritiсаl сltrеs to thе rеlirtionshipsЬеtwееn аngiospеrms аnd gупrIrospегmsand hеlp us undеrstаnd thе еariy еvolrrtionary innovations that allowеd angiospеrmsto Ьесomе so sttссеssful. Thе first sееd plants appеar in thе fossil rесord toward thе еnd of thе Dе. vonian, approхimatеty 360 million yеars ago' and, likе many othеr groups' thеir divеrsifiсаtionaссеlеratеdovеr timе. Sееd plants Ьеgan to divеrsify signifiсantly in thе Pеrmian, aЬout 270 rrrillionyеars ago' аnd Ьy aЬout 250 nrillion yеars ago g.vnrnospеrmshаd supplаntеd fеrns and othеr land plirnts as thе most сoll1пlon plant typе. G1,mnospеrmsmaintаrinеdthat dominirnсеfoг ovеr 150 million yеars. AngiospеГms madе thеir first appеaranсееarly irr thе сrеtaсеous) aЬout 1З0 million yеars ago' and Ьеgan thеir spесtaсulаrradiation soon thеrеаftеr.Thе radiation of angiospеrms ассеlеratеddramatiсally

at thе еnd of thе Сrеtaсеt divеrsifying rаpidly and . Thе aссеlеrаtеddivегs tiеd to thе divеrsifiсаtion giospеrms сoinсidеd witl and thosе thаt fеd on li dееd, thе сoеvolution of s p е с t a с u l a rс h a p t е г si n r diffеrеnt storiеs Ьесausе a story of mшtuirlismЬеt plant form and сhеmistr and аrms raсеs. l n s е с t p o l l i n а t i o nЬ r i n fееd on thе nесtar sесrе high sugaг сOntеnt.In tl thаt stiсk to its ехoskеlе morе nесtar, pollеn gr:rr thе stigпra, and thе insес plant is thе еffiсiеnt trans еst hypothеsеs aЬout thе favorеd shapеs,сolors, at pollеn, providing a fitnеs produсtion. [n rесеrrtyеа flowеr is sеlесtеd strong thеrеby inсrеasе an indi rhе idеа of sеlесrionfoг g odd at first rеading, rеsе i m p o г t а n tf t l r с еi n s h a p i Thеге arе rrrirnvstrikit orсhids tЬе pollеn is tra tion is a сomplеx proсеs thе fеmalе parts of thе fl rеquirеs thе insесtto wа mazе, so that pollеn is p a t i o n so с с u r w h с n o n l y еrs, a rеsult of a long еr еspесiallydгawn to thos that faсilitLrtе movеmеn m o s t s p е с t а с u l а rv a r i а t mutualisms Ьеtwееnpl: с о m p l е t е si г sе n г i r еl i f ес tat in ехсhangе for its sе Мan1' fеatuгеs of flov most familiar arе thе sц аnd many tlthеr insесt flowеrs of thе star аnrsе

Sееd Plапts /е sеparatеmаlе and fеnralе rеprolidual (сallеd monoесy)' althougЬ :ithеr сomplеtеly mаlе or fеmalе :d to stigmas Ьy wind. nсludе all plants whosе sееds arе uit, foгmеd from thе tissuеs of thе э ovеr 350,000 ехisting spесiеs of Lvеrsityof growth forms, inсluding еd, familiar hеrЬs likе liliеs and lсh as oаks, vinеs, and еvеn a widе dian plpеs. Flowеring plants havе hе mа|ority of spесiеs havе pеrfесt е flowеr)' Ьut thеrе arе quitе a fеw nd othеr spесiеsin whiсh somе intve flowегs of only onе gеndеr. AlЭmе arе sеlf-fеrtilizing, and othеrs ln and еithеr self-fertilization or егing plаnts arе pollinatеd Ьy in:е pollinatеd Ьy othеr аnimals, еs:s dispеrsе thеir pollеn Ьy wind iс plants аrе watеr poilinatеd, and rms havе a rеmarkaЬlе rеproduсэn. Pollеn sporеsсarry two nuсlei, : of gеnеs(a сomplеmеnt with half l. onе nuсlеusfегtilizеsthе fеmalе its owtr, to form thе еmЬryo. Thе :d with thе ovulе to foгm an organ : nutrition to thе dеvеloping еm_ m а j с l ra n g i o s p е r mg г o u p s Ь u r г e е r m s а n d m o s t g y m n o s p е г m si n :iоn is a dramatiс rеpгoduсtivе inand whеthеrit oссurs in thе samе n o t t o m е n t i o nw h е г h е гi г o с с u r s to thе rеlationshipsЬеtwееn anndеrst:rndthе еarly еvolutionary ]omе stl suссеssfirl. .есord tolvard thе еnd of thе Dе_ and, likе many othеr groups, ;o, ееd plаnts Ьеgan to divегsify sigY е a r sa g o ' a n d Ь y а Ь o u t 2 5 O m i l d fеrns аnd othеr land plаnts as s mаintainеdthat dominanсе for hеir first аppеaranсееаrly in thе rd Ьеgапthеir spесtaсul:rrradiaIspеrmsaссеlеrаtеddramаtiсally

аt thе еnd of thе Crеtaсеous;Ьy aЬout 50 nlillion yеaгs ago angi
84L)

8.'0

Sееd РIапts in dесaying animal Ьodiеs. Сеrtlrin groups of tropiсal orсhids lravе сomplех sсеnts whosе сomponеllts havе Ьееn miхеd i.rndmatсlrеd suсh tlrаt diffеrеnt spесiеsof Ьееsаrе attгaсtеdprеtЪrеntiallytrl diffеrеntspесiеsof orсhid. lv{any flowеrs havе fеaturеsvisiЬlе only in ultraviolеt light; insесtssее in thе ultrаviсllеt rangе, аnd thе so_сzrllеdnесtаr guidеs аrrd сlthеr murrkings,whiсh humans сallnot sее' attraсt insесrs and dirесt thеrтlto pагtiсLtlarparts of rhе florvеr. Thе сolors of flowеrs аlso sеrvе to attraсt insесts of сliffеrеnt typеs; howеvеr, rесеnt rеsеaгсh has suggеstеdthat in somе hаЬitats fl
Jaсk-in-thе-pо|pit' Аrisаеп strеaпls' гivеrЬlrtlks,and п It is a rnеmЬеr сlf thе Araс populaг ornamеntа[ hоusс саllеd a spаthе (thс Lrprig еnvе|opе with tЬе ovсrhan еithеr rnalе or fеmtrlс fltlw уеarsdсpеnJing tln it' ьiz

undеrgrсlr.rndtuЬсr iсallеd сrlmроunds thаt rnаkе thе havе еvсllvеd an еnOrm()u divеrsit,v of dеfеnsivе fеatr insесts is intсrtwiпесi ''vith

Sееd Рlапts ; of tropiсal orсhids havе сomрlеx d and matсhеd suсh that diffеrеnt o diffеrеnt spесiеs of orсhid. Мany оlеt light; insесts sее in thе ultravi'nd othеr markings' whiсh humans to partiсular pаrts of thе flowеr. nsесts of diffеrеnt typеs; howеvеr, : haЬitats flower сolor sегvеs as a hе flowеr that faсilitatе pollen gеrlnts is quitе diffеrеnt. A long arms it plant tissuе fоr food and plаnts r has pгoduсеd a variеty of intеr:еmarkaЬ1еof thеsе fеaturеs is thе ,tsthat arе distastеfulor toхiс and rom аlkaloids tO tеrpenеs' thеse luld-Ье dinеrs (sее figurе). Thеsе сеrtain plants usеful for humans; tuman as ''vеll as insесt сonsump1at attraсt humans to thеir сonсеll division, likе taxol' havе Ьееn rtiсular disеasеs. ot pеrfесt, and еvеn plants with ts suffеr prеdators. For еxamplе, that disсouragеmost insесts, but )uttеrfliеs' thе roots Ьy larvaе of 'ееd Ьugs.Еaсh of thеsе spесiеs sеquеstеrthе toхin in spесializеd )nsumе milkwееd parts, Ьut thе thеm distastеfulto many of thеir againstthеm. , spесializеd hеrЬivorеs rеprеsеnt :t rеlationships.Thе morе typiсal ; is ехploitеd Ьy many diffеrеnt :сiеsis found on only a vеry fеw Lltof thе insесt's inсrеasing foсus rе tradе.off bеtwееn thе fеaturеs dеfеnsеsystеmand thosе nееdеd p I a n t s .T h е r е s u I гi s a p а r t е r n i n nly on сеrtain grouрs of plants. und only on passionflowеrs. prominеnt rolеs in еvolutionary ',еd rеproduсtivе Ьiology of orrtе inhеritanсе (disсrеtе gеnеs) : usеd in sсlmеof thе most influlrtiсular thе work of Hugo dе

&

АrisаеmаtripЬуllum,is аn hеrЬасеouspеrеnnialfound along Jaсk-in-thс-pulpit, thrtlughoutеastеrnNorth Amеriсa. strеams'rivеrЬanks'аnd п.rсlist Ьtltttlmlаrrds It is a mсmЬеrof thе Araссас,thе farтi[ythirtinсludеsсannа lilliеsand othеr popular ornamеntalhousеplants. Thе flor,vеrs аrе Ьornе on a сylindriсalstruсturе саllеdа spаthе(thеupright ..jасk''),whiсh is еnсlosсdby thе сup-shapеd with thе оvеrhangingflаp (thе..pulpit'')'An individualplant produсеs еnvеlсlpе еithеr mаlе or fеmаlе flоwеrs and сhаngеsits gеndегЬaсk and forth ovеr thе Thе lеavеsand yеаrsdеpеndingtln its sizе and rесеnthistoryof rеprоduсtiсln. undегgroundtuЬеr (саllеda ..сorm'')сontainсalсium Oхatесrystalsand alkaloid сompoundstЬat mtrkеthе plаnt tсlхiсtсl mammalsand ln
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SееdPlапts Vriеs. Sсlmеof thе еаrliеststudiеs сlf lсlсal adаptatiсln,whiсh showеd thаt diЁ fеrеnt populаtiоns of thе samе spесiеswеrе adaptеd to diffеrеnt loсаl сondi. tions, wеrе donе with plants, in partiсular thе сommon gardеn ехpеrimеnts of Gotе Turеsson and thе fаmous rесiproсal transplant ехpеrimеnts Ьy Jеns ..Jеns Сlausеn and сollеaguеs(sееthе alphaЬеtiсalеntry Сlausеn'' in this volumе). Thе woгk of Anthony Bradshaw and his studеntson mеtal tolеranсеin сеrtain grassеsproduсеd саsе studiеsof rapid еvсllutiсlnin rеsponsеto anthгopogеniс еnvironmеntal сhangеs, аnd thе studiеs of Janis Antonoviсs and studеntson anthеr smut disеasеin сampion hеlpеd сonvinсе еvolutionaryЬiologists and есologistsаlikе of thе еnormous rolе that disеasеplays in natural populations (sееthе alphaЬеtiсalеntry ..JаnisAntonoviсs'' in this volumе). Мolесular biology hаs faсilitatеdеnormous аdvanсеsin сlur undеrstanding of flowеring plants, has rеvеalеd сonsidеraЬlе surprisеs, аnd has opеnеd wholly nеw quеstions. Thе phylogеnеtiс rеlationships among sееd plants hаvе Ьесomе сlеaгеr;thеsе rеlationships point to a smаll shruЬ from thе island of Nеw Сalеdonia, Аmborеllа trichopodа, thе Watеr liliеs, and a smail group of diminutivе, mosslikе aqrratiсplants as thе rеmaining rеPrеsеntativеs of thе еarliеst angiospеrm familiеs. Thе еmеrging piсturе of thе rеlati
The SеlfishGene (R

Thе Selfish Gепе (1976\ Riсhard Dawkins artiсLll Ьесomе onе of thе stand also notaЬlе for its spесu sponding notion tl| mеmс A с с o г d i n gt о D а w k i n s dividuals, familiеs, оr gr gеnеs that havе Ьееn mos tесt thеmsеlvеsаnd Ье rt protеin сoаting that surr nеtiс informatiсln stсlrеd аrе to Ье undеrst
Ьrain of anothеr. In this way mеmеtlсе namiсs as gеnеtiс еvolut еvolutiсln has sprеad so ttrral еvolution impliсitl1 ologiсal еvolution obеy advoсatеs. In thе сonсlu

Thе SеlfishGеnе daptzrtion,whiсh showеd that difе adaptеd to diffеrеnt loсal сondit h е с t l m m t l ng a r d е n е х p е r i m е n г s :al transplant ехpеrimеnts Ьy Jеns rl еntr,v..JеnsСlausеn'' in this volhis studеrrtson mеtal tolеranсе in id еvoludon iп rеsponsеto anthrostudiеs of .JirпisAntonoviсs аnd l lrеlpсdсtlnvinсееvolutiorrzrryЬirs rolе thас disеasеplays in naturаl tis Antсlnсlviсs''in this volumе). rus ас]vаnсеsin our undеrstanding lraЬlе surprisеs' аnd has opеnеd rеlationships amonЕ] sееd plants oint tо a small shruЬ from thе is>odа,the lvatеr liliеs, and a small t s a s t l ] еr е l n l t i n i n gг е p r е s е n t a t i v е s еrgingpiсturе сlf thе rеlаtionships / qllrstions аЬout thе distriЬr.rtiorl imnospеrms' in partiсulаr wlrеtlrеr tvе еvolvеdmultiplе tinrеs.Sеvеral : Ьееrrdisсovеrеd,and thе сontrol l s . p е г а I sа, n t h е r s .а n d s t i g m a t а ntriЬrrtеd to thе еmеrging piсturе сan сombinе to produсе an еnoгlting that what may sееm at first y in faсt bе еasily gеnеratеdЬy thе lg grnеs. rгесtsold idеаs' аnd thе study of . Мr.rtаtionsin thrее of tlrе gеnеs э I a n tг h а tс а r г i е st h o s е m u r а r i t - l l l s tеаd сlf flowеrs.This suggеststhat on's сo-opting thе gеnеs that сonlvеl purposе.This idеа was advofigurеthan Johann WoIfgang von 3St.

Stеvсns'anс]N{. J. Dоnоghuс. prсlttсh,Sundеrlarrd,rVIA:Sinauеr IPlапts. Сhiсаgtl: Univеrsity оf K/.Сhasс. 2005. Ph1'klgепу апd ': SinauеrAssOсiiltCs. iиtiсltl of Plапls. Nеw Yоrk: oхford

-1.r.

Thе Selfish Geиe (Riсhard Dawkins) Tbе Selfisb Gепe (\976) ts a highly influеntial and popular Ьook in whiсh ..gеnе's-еyе''pеrspесtivеon еvolution. It has Riсhard Dawkins аrtiсulаtеs a Ьесomе onе of thе standaгd statеmеntsof gеniс sеlесtionism.Thе Ьook is also notaЬlе for its spесulativеdisсussion of сtrlturalеvolr.rtionand thе сorrеsponding n()ti()nс>fmеmеtiс euolutioп. Aссording to Dirrvkins,tlrе rеal aсtors in evolutionirгyproсеssеsarе not in. ()r groups Ьut gеnеs. [n tlrе irгms rасе
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Sepkoski somе of thе amЬiguity aЬout lruman Ьеings that runs through his Ьook. on thе olrе hаnd, hе сlеаrly \4/antsto sее Lls as paгt сlf thе gеnеrаl sеlfish-gеnеpiс. turе. on thе otlrег hand, with thе introduсtion of mеmеs' hе suggеststhat pеrhaps Wе сan еsсapеour Ьiology. ..\й/еarе Ьuilt as gеnе maсhinеs and сulturеd :rsmеmе maсhinеs, Ьut wе havе thе powеr to turn against our сrеators. .Wе, alonе on еi1rth)сan rеЬеl аgainst thе tyгanny сlf tlrе sеlfish rеpliсators''

( p .2 l s ) .

BIBLIoGRAPнY Blirсkt-trorе,s. 2000. The 1|4еlnеМасhiпс. Oхfсlгd: o'xford Ur-rivеrsityPrеss. Dat'kins, R. 1976. Тhе Sефsh (]епе. Ох{ord: oxford Urrivеrsity Prеss. (Тhirtiеth аnnivеrsary еdition with a nеw prеfaсе,2006.) .!Иilson' SсlЬеr, Е., and D. S' 1997, Uпtсl Оthars: Thе Еuolutiсlп of Altruism. Саrr-rЬridgе, МA: Hаrvаrd Uпir,еrsitvРrеss' Stеrеlny' K.2007. Dашkiпs t's,Сrшld: Sиruiuаl of thе Fittеst.Lоndсln: Totеm Books. Stеrеlny,K., and P' Kitсhеr. 198B. Thе rеturn of thе gеnе..|ourпаlof PbilosopЬу 85, -Z.Е. лсl' 7: ЗЗ9_З62,.

Sеpkoski,J. Jоhn ..Jaсk,''lr. (1948_1999) J a с k S е p k o s k i w а s f o r t u n a t е t ( ) е n t r r t h е f i е l d o f p a l е o n t o l o g yl l t a t r a n s i tiorrаl momеnt ir-rthе disсiplinе's history. Whеn hе bеgan grirduatе study at Hаrvard in 1.970,thе fiеld lrad not yеt sееn somе of thе Ьrеaktlrгoughthеorеtiсal idеas of thе 1970s (suсh as Nilеs Еldrеdgе and Stеphеn Jаy Gould's t h е o r y o f p u n с t u a t е d е q u i l i Ь г i a o r S t е v е n S t a n l е y ' sw o r k o n s P е с i е ss е l е с tion), Ьut palеontologists wеrе alrеаdy in thе рroсеss of dirесting thеir work toward еvolutionary thеOry. Sерkoski's еdr.rсationwas thеrеforе a mixturе of o|d and nеw: fгom Bеrnhard Kummеl he lеarnеd traditional g l o Ь a l Ь i o s t r a t i g г a p l r y( t h е u n d е r s t a n d i n go f f o s s i l d е p o s i t s i n t h е с o n t е х t of thеir plaсе aIrd гimе), whilе Gould ti.rughthim Ьroadеr, mzrсroеvolutionary thinkirlg. Hе аlso Ьеgan to rеfinе an intеrеst in using сomputеrs to quantify and modеl trеnds in thе fossil гeсord, whiсh involvеd using сomp l е х m u l t i v а r i а t е s t а t i s t i с s .A l o n g w i t h h i s с o l l е a g u еD a v i d М ' R i r u p , S е p koski was onе of thе first palеontologists to aсtеmpt sеrious statistiсаl analysis of thе fossil rесord, and his work is partially rеsponsiЬlе for thе еmеrgеnсе of an important branсh of palеontology known as quаntitarivе palеoЬiolog,v. Sеpkoski's major сontriЬution to еvolutiоnarv thеory was to dеvеlop and tеst mеthodologiеs аnd rеsourсеs for dеtеrmining pattеrns in thе fossil rесorс].Thе fouпdation for tlris work сalt1еfrom Ьis сarееr-long projесt to сompilе arrd updаtе а dilt:rЬasеlisring all krrorvn fossil familiеs аnd gеnеra of mаrinе аnirrrals.This list' whiсh wzrs Ьеgun in thе mid-1970s and сr.rrrеntlУ stаnds at morе than 3,500 fаmiliеs and 37,000 gеnеra' traсks thе first аnd l:rst appеarz]nсеsof taxа in thе fсlssil rесord aIrd providеs tЬе Ьеst аnd most ассuratе еstimatе of thе origirrationsаnd ехtinсtions of nrarinе orgi1nisms availaЬlе to sсiеntists.Drawing on this rеso[lrсе' Sеpkoski pеrformеd

e s е r i е so f p i o n е е r i n g' Р h а l l е r о z с l i се o r l ( t h ер prеsеnt, during whiсh was to сomparе thе t rссord with пlагhеmlt l < l g i сIаt h е r l r i е os f i ' l n r r а t е st l f o r i g i n а r i o nа n t Ьirth and dеath for po1 I а n d s .Т h i s f i l l d i n gs u Ьy impliсation, spесiеs v i d u a l s ,а n d t h а tt h е h l to Ьiologiсal populatiс t i l l l с е ,t h i s w t ' r k a l s o i r vеlopеd сonсurгеrrtlyI rvhiсh trеatеdtаxtlno organisms. From his сarеful anа s е v е г а Il r l аj < l гt h е tl r е t i с of lifе. Thе nrost impor essays puЬlished Ьеtwе of maсroеvolutionduri l а p p i n g s i g n l o i d а lt S - s p е г i o d so f с v o l u t i o n е. girnisms, followеd Ьy t w,ill proЬaЬlr' Ье Sеpk lrе gainеd сonsidеrаЬlе Ьatе сonсеrtringmass е . l n а n a I y s i sс l ft h е f o s s i a t f а i r | yr е g u l l l гi n t е г v а г o t h е p r е s е l r t )Т. h е f . r yеars Was partiсularl phеnomеnon, quitе pos s p е с t r l а t aе Ь t l t t t h е ч r l u d i d , a n d а r r u m Ь с ro i l i n g f r o m t е r r е s t r i асl а u t o е х t г а t е r r е s t r i af lа с t t t h е g a l а с t i сp l а l l е )a n w h i с h r m а g i n е dt h а t а r lar systеmеvеry 26 milJ h u г r I i n gt o w а r d t h е е а г S е p k o s k i h i m s с l fс o n s i r r o г е dt h а r h i s w t l r k o r сlvеrallsсiеntifiсoutpu1 S е p k o s k i с о r l t r i Ь u t е dr arralysisof Ьiodivеrsitу srudуof nl:1сгOеvoIu

Sepkoski i that runs through his Ьook. on art of thе gеnеral sеlfish-gеnеpiс:tion of mеmеs' hе suggеsts that е built as gеnе maсhinеs and сul)Wеr to turn against our сfеators. УrannУ of thе sеlfish repliсators''

d: Oхford UnivеrsityPrеss. хford UnivеrsityPrеss.(Thirtiеth b./

Тhе Еuolutioп of Аltrиism. ,f thе Fittеst. London: Totеm thе gеnе.Jourпаl сlf Philosophу 85'

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-reee) iеld of paleontology at a transiИhеnhе bеgan graduatе study at somе of thе Ьrеаkthrough thеodrеdgе and Stеphеn Jay Gould's Stanlеy'swork on speсiеs sеlесr thе proсеss of dirесting thеir ;ki's еduсation wаs thеrеforе a Kummеl hе lеarned traditional of fossil dеposits in thе сontехt rt him Ьroadеr' maсroеvolutionintеrеst in using сomputеrs to o r d ' w h i с h i n v o l v е du s i n g с o m сollеaguе David M. Raup' Sеp.s to attеmpt sеrious statistiсal . is partially rеsponsiЬlе for thе ontologyknown as quаntitativе tionary thеory Was to dеvеlop еtеrmining pattеrns in thе fossil . f r o m h i s с а r е е г - l o n gp r o j е с t t o ,nown fossil familiеs and gеnеra :gun in thе mid-1970s and сurrd 37,000 gеnеra' traсks thе first есord and providеs thе Ьеst and r n d е x t i n с t i o n so f m a r i n е o r g a n is rеsourсе' Sеpkoski реrformеd

a sеriеs of piсlnееringanalysеs of thе rесord of marinе divеrsity during thе Phanеrozoiс еon (thе pеriod of timе from aЬout 540 million yеars ago to thе prеsеnt' during whiсh most lifе on еarth еvolvеd). His intеrеst in this study was to сomparе thе ratеs of divеrsifiсation and еxtinсtion in thе aсtual rесord with mathеmаtiсal modеls for population growth dеrivеd from Ьiologiсal thеoriеs of island Ьiogесlgrаphy.Sеpkoski found that thеsе mаtсhеd: ratеs of оrigination and ехtinсtion of tахa in thе fossil rесord mirror rates of Ьirth and dеath for populations of оrgаnisms сompеting for rеsourсеs on islands. This finding srrggеststhаt taхonomiс groups (familiеs, gеnera, and, by impliсation' spесiеs)arе suЬjесt to thе samе population prеssurеsas individuals, and that thе historiсal pattеrn of сladе divеrsity is dirесtly analogous to Ьiologiсal population growth. Bеyond this сonсlusion's intrinsiс importanсе, this work also indirесtly supportеd thе thеory of spесiеs sеlесtion dеvеlоpеd сonсurrеntly Ьy Gould and Stanlеy' among othеr pаlеontologists, whiсh trеatеd taxonomiс groups (likе spесiеs) as analogous to individual organisms. }-rom his сarеful anаlysis of fossil data, Sеpkoski was aЬlе to ехtrapolatе sеvеrаlmajor thеorеtiсalartiсulations of thе naturе of divеrsity in thе history of lifе. Thе most important is known аs his thrее-faunasmodеl: in a sеriеsof еssayspuЬlishеd Ьеtwееn 1976 and 1984, Sеpkoski arguеd that thе pattеrn of mасroеvolution during thе Рhanеrсlzoiс сould Ье rеprеsеntеdЬy thrее ovеrlapping sigmoidal (S-shapеd)сurvеs. Thеsе сurvеs rеprеsеnt thrее distinсt pеriods of еvolution' еquiliЬrium, and dесlinе for a сharaсtеristiс sеt of organisms, followеd Ьy thе risе of a nеW fаunal group. Although this modеl will probaЬly Ье Sеpkoski's most fаг-геaсhingand lasting ассomplishmеnt' hе gainеd сonsidеrаblеnotoriеty for partiсipating in a widеly puЬliсizеd dеЬatе сonсеrning mass ехtinсtions. In thе еarly 1980s hе and Raup puЬlishеd an analysis of thе fossil rесord that showеd distinсt pulsеs of mass еxtinсtion at fairly rеgular intеrvals during thе post-Palеozoiсеra (250 million yеars ago tсl thе prеsеnt).Thе faсt that thеsе pulsеs hаppеnеd roughly еverу26 million yеars Wаs partiсularly signifiсаnt: thеir rеgularity suggеstеd a rесurring phеnomеnon, quitе pсlssiЬlyof aЬiotiс origin. Although Sеpkoski dесlinеdto spесulatеaЬout thе sourсе of thеsеsееminglypеriodiс еvеnts'оthеrs сегtainly did, and a numЬеr of highly spесulativесandidatеs wеrе put forward, ranging from tеrrеstrialсausеs(rеgularpеriods of volсanism or сlimatiс uphеaval) tO еХtratеrrеstrial faсtors (сosmiс radiation, еarth's сyсliсal motion thrсlugh thе galaсtiс planе) and sсiеnсе fiсtion (thе so.сallеd Nеmеsis hypothеsis' whiсh imaginеd that an сlrЬiting ..dеathstar'' passеd сlosе еnough to thе solar systеm еverу26 million yеars to sеnd сomеts from thе nеarЬy oort Сloud hurtling toward thе еarth).Dеspitе oftеrrЬеing assoсiatеdwith thеsеthеoriеs, Sеpkoski himsеlf ссlnsidеrеdhis partiсipation in thеsе dеЬatеsассidеntal and nсltеd that his work on pеriodiсity oссupiеd a rеlativеly minor plaсе in his ovеrall sсiеntifiсoutput. Dеspitе his untimеly dеаth in 1999 at thе agе of 50' Sеpkoski сontriЬutеd a numЬеr сlf important apprсlaсhеsto mathеmаtiсal analysis of Ьiodivеrsity and palеoесology that havе hеlpеd shapе thе сurrеnt study of mасroеvolution.

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Sheppаrd B|вLloGRAPнY Rrrsе,M. |999. М1'5197у of Мlstеriеs: ]s Еuolutilllt,:tSoсiаIСoпstruсtitltt! СanrЬridgе, МA: Hаrr,аrd Univеrsity Prеss. Sеpkoski, J.J.' J'. l984. A kinеtiс mоdеl сlf Phanсrozoiс taхоnonriс сlivеrsitу.lll. Post.Palеozсliсfirmiliеsапd mаss ехtiПсtions.Pаlеr''biоIсlgу 1О 216_267. 1994. !Иhаt I did with llr)/rеsс1r.сhсi]rееr;()r' L{oц,,геsеаrсЬ oп Ьiоdivегsity yiеlсlеddаta сltrехtinсtion. In !7. Clеn, еd.,Тhс Маss Ехtiпсtiott Dеbаtеs:Hoш Sсieпсе Works iп а Сrisis' 1з2_|44' Stanfоrrl,СA: Stаnfоrd Ur"rir,еrsity Prеss.

-D.Se.

(192|-797 6) Shеppard,Philip |\Д'. Philip Shеppard was thе Ьrightеst of thе y()ung mеn gathеrесlaround Е. B. Ford in tl.lеsсhotll of есoltlgiсalgеnеtiсsfoundеd at oхfoгd Univеrsity iп thе .War yеars аftеr World II. Сorning of[ thrее yеaгs as it prisсlnеrof war, Shеppard rapidly mаdе his mark, although it is аn indiсatiоn of tlrе statе of Ьio. logiсal еduсation that hе diсl not gеt a first-сlirssdеgrееЬесaltsеhе spеnt too muсh of his tirrrеthinkirrg :lЬout gеnеtiсsilnd not еnough ol1 thе traсlitional suЬjесtsof morphology ar-rdphysiоlсlgy.Shеppard Was swеpt up in thе work that Ford and Rсlnаld Fishеr wеrе doing on tlrе motЬ l>с|пс|хia and thеn Ьеgan to makе his о''vr-r importirnt way in thе sеlесtion studiеs hе did witlr fеllow Oхonian A. J. Сain. Thеy lсlokеd at thе snail Сеpаеа пеmorаLisand showеd thе falsit,vof еаrliег сlaims that thе variеd m:rгkingst>fthе snail-Ьandеd. unЬandеd, pink, yеllow, Ьrown, and sсl forth-had no аdaptivе signifiсar-rсе. To thе сontrary, thеy wеrе aЬlе to provе that thе markings play a major rоlе in protесting thе snails from prеdаtors.сhiеflу tlrrushеs,аnd thаt thе markings vаry aссording t() thе Ьaсkground-Ьеесh'uvoodflсlсlr,ditсhеs Ьy hеdgеrows, mеadows, and thе likе. Showing thаt Ьу now nеo-Darwinian studiеs wеrе llесoming vеry muсh a joint Arrglo-Amеriсan еndеavor, Shеppard spеnt a yеar (19.54_1955)working on Drosсlphilа in thе laЬoratorv сlf Thеodosir.rsDoЬzharrsky at Ссllr.rmЬia Univеrsity in Nеw Yсlrk' Bпt аlthough this сlеarly strеngthеnеdShеppаrd's knowlеdgе of alrd intегеstsin undеrlying gеnеtiсfaсtors in еvсllution,studiеs of organisms in naturе wеrе always сlosе to Shеpparсl'shеart, and thеsесontinuеd aгld inсrеаsеd whегr hе movеd to Livеrpool LJnivеrsitvin 1956' Togеthеr rviсh Сyril Сlarkе, Shеpparсlсonduсtеd lеngthy аnd пrassivеstuсliеson Ьuttеrfliеs,unсovеring thе naturе аnd сausеs сlf mimiсry. This is pеrhaps thе most vеnегaЬlеtopiс in Dаrlviniаn sttrdiеs,going Ьaсk to thе l860s and thе pathЬrеaking work of Hеnry \й/altеrBatеs, Ьut had long Ьееrra topiс сlf сontrovеrsy, primarily Ьесausе mirтiсry oftеn sееms to Ье thе ftrnсtion of onе gеnе, and so it is hard tс-lsее how natural sеlесtion ссluld Ье thе signifiсant сausе.[n rеsponsеto suсlr a mlltarionist viе'nv,pushеd Ьy Rеginald Punttеtt,in Ьis Genetiсаl Thеorу сlf I'Jаturаl SеlеctiLlп(1930) Fishеr arguеd that many gеnеs сall Ье involvеd in r-rrakingfсlr mimiсry thаt саl-lthеn Ье paсkagеd as onе or a fеw supеrgеrrеs.It Was thе wсlrk of Shеppard and Сlarkе that showеd this ro l.е tru..

Although thе 1950s r iеs, in othеr respесtsthi ogy was сonqr-rеringtht Lеd Ьy Ford, thе еvol at Livеrpool was givе Nuffiе[d' Еnglarrd'slеad Amеriсa). Thе foшnda and Сlarkе сonvinсеd r fliеs сould sеrvе as lnO This lеd to major and rn groupsand assoсiаtеd Ьlood-group sysrеm'on inсompatiЬlе witlr that t Shеpp:rrddiеd at thе i most important еvolutt influеntiаl and oftеn-rе tion, 19-58). B|вLIoGRAPHY

B а t е sH ' . ! и . [ 1 8 6 3 ]1 8 9 2 Мr-rrrаy. Сain, A. J., аnd P. М' Shе Сеpаеапеmorаlis\L) 19.52.Thе еifесtst Сеp аесlпеtпсlrаl is.Hе l 9 5 4 . N a t u r a ls е l Сlarkе,С' A., R. B. МсСo sесrеtorсlrаrасtеr in г 21_2з. Сlarkс, с. A.' D. А. PгiсеI SесrеtionсlfЬloodgrо n o . . S 1 2 26: 0 з - 6 0 7 . Сlarkе,С. A., and P. M. S Масhaongrсlupof sw 1959a.The gеnеt Pаpi l io glаuсus, I,inn, ! 9 5 9 Ь .T h с g е n е т Аfriса. Gепеtiсs44 7 I 9 o 0 c .Т l r еg е n с r p olуtrop hиs, |tlеsеr еs' 1960b.Thс еvоlu 7з-87. I 9 6 0 с Т. h ее v о l t |4:16З-17З. 1960d.Supегgеn

|9ь2. Тllе p(.IlctiL

159-161. Fishеr,R. A. 1930.Тhе Gt UnivеrsityРrеss. P u n n е t tR, . ( , . l 9 | \ . М i l п Prеss'

Shеppаrd

n а SoсiаI Сoпstruсtioп? rozoiс taхonomiс divеrsity. III. Pаlеobirllrlgу 7О 246-267. ; or' Нow rеsеarсhon Ьiodivеrsity 'hе Маss Ехtiпсtil-lп Dеbаtеs: Hottl , СA: Stаnford Univеrsity Prеss. -D.Se.

rng mеn gathеrеd around Е. B. dеd at Oхford Univеrsity in thе еars as a prisonеr of war, Shеpn indiсаtion of thе statе of Ьioass dеgrееЬесausеhе spеnt too J not еnоugh on thе traditional lpard was swеpt up in thе woгk lе moth Pапахiа and then Ьеgan :tion studiеs hе did with fеllow I Сеpаеа пеmorаlis and showеd гkingsof thе snail-Ьandеd, un1ad no adaptivе signifiсanсе.To е markings play a major rolе in :hrushеs'and that thе mаrkings od floor, ditсhеs by hеdgеrows, iеs wеrе Ьесoming vеry muсh a ) е n t a y е a r ( 1 9 5 4 _ 1 9 5 5 )w o r k LosiusDoЬzhansky at СolumЬia :lеarly stгеngthеnеdShеppard's еtiс faсtors in еvolution, studiеs ihеppard'shеart, and thеsе сonе r p o o l U n i v е r s i t yi n 1 9 5 6 . T o l lеngthyаnd massivе studiеs on of mimiсry. This is pеrhaps thе oing Ьaсk to thе 1860s and thе rt had long Ьееn a topiс of сonэеms to Ье thе funсtion of onе llесtion сould Ье thе signifiсant p u s h е dЬ y R е g i n e l d P u n n е t t .i n 1930) Fishеr arguеd that many y that сan thеn Ье paсkagеd as of Shеppard and Clarkе that

Although thе 1950s wеrе ехсiting timеs for Darwinian еvolutionary studiеs, in othеr rеspесts things wеrе diffiсult. Thе nеwly formеd molесular Ьiology Was сonquеring thе lifе sсiеnсеs,taking grants and posts and studеnts. Lеd by F.ord, thе еvolutionists fought Ьaсk (Rusе 1996). Major funding at Livеrpool was givеn Ьy thе Nuffiеld Foundation (sponsorеd Ьy Lord Nuffiеld' Еnglаnd's lеading сar industrialist,thе еquivalеnt of Неnгy Ford in Amеriсa). Thе foundation's mandatе \,\'asmеdiсal rеsеarсh, and Shеppard and Сlarkе ссlnvinсеd it that studiеs of fast-Ьrееdingorganisms likе Ьuttеrfliеs сould sеrvе as modеls for human disеasеswith gеnеtiс undеrpinnings. This lеd to major and in rеspесts vеry suссеssful work on suсh topiсs as Ьlood groups and аssoсiatеd illnеssеs and' spесifiсally with rеgaгd to thе Rhеsus Ьlood-group systеm' on thе proЬlеms assoсiatеdwith ЬaЬiеs whosе Ьlood is inсompatiЬlе with that of thеir nrothеrs. Shеppard diеd at thе agе of 55 of aсutе lеukеmia, rесognizеdas onе of thе most important еvolutionists of tl.rеmid-twеntiеth сеntury' not lеast for his influеntial and oftеn-rеvisеd tеxt IltrаtиrаlSeleсtioп апd Heredity (first еditiоn, 1958). в|BLIoGRAPHY Batеs,H. !и. l1863] 1892.Thе Nаturаlistсlпthе RiuеrАmаzoпs.London:John Murrаy. Сain, A. J., and P. М. Shеppаrd.19.50'Sеlесtionin thе рolymorphiсlаnd snail Сеpаеапеmorаlis(I'\.Hеrеditу4: 27 5-294. 1952.Thе еffесtsсlfnatur:rlsеlесtionon Ьodусolour in thе land snail Сеpаеапеmorаlis.Неrеditу6:217_231, ] 954. Nаtural sеlесtionin Сеpaеa.Gепеtiсs39: 89-116. Сlarkе,С. A.' R. B. МсСoI"rnеll' аnd P. М. Shеppаrd.1960.ABo Ьloodgroupsand sесrеtorсhаraсtеrin rhеumatiссагditis.BritishМеtliсаlJourпаl1, no. 5165: 21-2з. Сlarkе,с. A., D. A. PriсеЕvans,R. B. MсСonnеll' аnd Р. М. Shеppard.1959. Sесrеtionof Ьlоod grсluрirntigеnsаnd pеptiс о|сer.British МеdiсаIJoиrпаl 1, no. 5122:60З_607. Сlarkе,С. A., and P. М. Shеppard.19.5.5. A pгеliminaryrеporton thе gеnеtiсsof thе Maсhаongroupof swallowtаilеd Ьuttеrfliеs. Еuolutioп9:182-201. 1959а.Thс gеnеtiсsof somеnrimеtiсforms of Pаpilio dаrdапus,Brоwn' аnd Pаpilioglаuсus,|inn.Joиrпаlоf Gепеtiсs56:236-260. 1959b.Thе gеnеtiсsof Pаpilio dаrdапus,Brown, IRaсe сепеаfrom South Afriсa. Gепеtiсs44: 1З47-1З58. 1960a.Thе gеnеtiсsof Pаpilit.ldаrdаnus,Brown' II Raсеsdаrdапus' polуtrophus,mеsеrеs'and tibullus.Gепеtiсs45: 439-457. 1960b.Thе еvоlutionсlfdominаr-rсе undеrdisruptivеsеlесtion. Неrеditу14 7з_87. 1960с.Thе еvolr.rtiсln сlf mimiсry in thе ЬrrttеrflуPаpilio dаrdаnus.Hеrеditу 1 4 :1 6 З - 1 7 З . 1960d.Supеrgеnеs and п-rimiсry. Неrеditу14: 175_185. 1962.Thе gеnсtiсsof thе rтimеtiсЬuttеrfly,Pаpilb glаисus,Ессiogу 4З: 1 59-16\. Fishеr,R. A. 1930. Thе GепеtiсаlThеllrу of Nаtиrаl Sеleсtklп.Oхfоrd: Oхford UnivеrsityPrеss. Punnеtt'R. с. 191.'.Мimiсrу iп Buttеrfliеs. СarnЬridgе: CamЬridgеUnivеrsity Prеss.

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Ь|mpson Rusе, \4. 1996. Мoпаd tсl Мап: Тhе Сoпсерt of Pпlgrеss iп Еuolиtiспаrу Вiсllogу. СamЬridgе, МA: Harvard Univеrsity Prеss' Shеppard, P. М. 1958. Nаtиrаl Sеlесtillttапd Hcrеditу. Lоndon: Нutсhinson. -М.R.

Simpson, Gеorgе Gaylord (1902_1984) Gеorgе Gaylord Simpson was an Amеriсan palеontologistand an еxpеrt on mammal еvolution. Hе madе profound сontriЬutions to еvсllutionarythеory' systеmatiсs'and historiсal Ьiogеography.Hе Ьuilt lasting links Ьеtwееnpalеоntology and Ьiology. Simpson was raisеd in Сolorado аnd attеndеd thе Univеrsity of Сolorado in Bouldеr from 1918. Hе Ьеgan in jоurnalism and litеrаturе Ьut disсovеrеd a passion for palеontology during his third yеar. To dеvеlop this intеrеstSimpson transfеrrеd to Yalе Univеrsity in 1922, whеrе hе еarnеd a РhB (1 923) and a PhD (1926). Simpson's rеsеarсh intеrеsts first foсusеd on mammals thаt livеd during thе agе of dinosaurs. Aftеr Yalе Simpson spеnt a yеar in Britаin (1926-1927) to study сollесtions of thе sаlтlе mammals hеld in Еurоpеan musеums. Simpson joinеd thе Amеriсan Мusеum of Natural History in Nеw York in 1927 and stayеd morе than 30 yеars. Simpson rеplaсеd his mеntor, !7illiam Dillеr Мatthеw, whсlm Simpson hеld in high еstееm.Thе Amеriсan Musеum ownеd onе of thе world's largеst сollесtions сlf vеrtеЬratе fossils. Simpson flourishеd during thе 1930s and ]940s dеspitеthе Grеat Dеprеssion.Patrons gavе him funding for sеvеral ехpеditions. In North Amеriсa Simpson сollесtеd fossils in Florida and Montana, as wеll as aсross thе еntiге Sоuthwеst. Abroad hе lеd ехpеditions to Vеnеzuеla, Braztl, and Patagсlnia.Simpson also nеarly rеaсhеd Mongolia, Ьut Soviеt offiсials rеfusеdhim pеrпrissionfor politiсal rеasons. Latеr in his lifе Simpson hаd a rеputation foг bеing an armсhair naturalist. This is unfair. Hе lovеd to travеl and spеnt a signifiсant amount of timе away from his homе institutions.Hе wаs a proud mеmЬеr of thе Ехplorеrs СluЬ, and hе always еnjoyеd thе advеnturе of travеl. In 1942 Simpson voluntееrеdfor military sеrviсеаnd sеrvеdin military in. tеlligеnсеin North Afriсa, Siсily, and Italy. Fluеnt in kеy lаnguagеs,inсluding Frеnсh' Gеrman, Spanish, and ltalian, Simpson was idеal for suсh work. In thе sеrviсе hе lеarnеd AraЬiс. Simpson's sеrviсе allowеd him to еsсapеа сгisis for palеontology at thе Amеriсan Мusеum. Its dirесtor, AlЬеrt Parr, lrad rесеntly rеorganizеd thе musеum. In this rеorganization thе palеontology dеpartmеnt was dissolvеd. It was sееn as antiquatеd and rrnsuitaЬlеfor a modеrn Ьiologiсal institution. Parr was an oсеanographеrand wantеd morе еxpеrimеntal Ьiology. on Simpson's rеturn in 7944, сoolеr hеads prеvailеd. Simpson withdrеw his rеsignation and was appointеd hеad of thе rеorganizing dеpaгtmеnt. In 1956 Simpson suffеrеd an aссidеnt whilе on аn еxpеdition in Brazil. This lеft him disaЬlеd. Hе nеvеr undеrtook еxpеditiсlnwork again. Friеnds also notiсеd psyсhсllogiсalсhangеs.Indееd,nonе tlf his writing аftеr tЬе aссi-

dent matсhеd his еarlrе aЬandonеd Ьy ссlllеagu his rеsignation in ] 9.59: ( M С Z 1 a t H а r v a r dU n i v thе most important еvol Еrnsr Мayr, Bryаn Рattс largеly workеd alonе. H formally rеtirеd in 1982 Simpson marriеd twi ( 1 8 9 9 _ 19 8 8 ) ' p r o d u с е d morе than a dесadе thе r Divorсе сamе in 19З8. w i r h A n n а ( A n n е )M r r l а psyсhologist who trаinе ехpеrt on сarеег сhoiсе Thеy had ntl сhildrеn to Simpson's сhildrеn. Simp сarееrs' inсluding a Ьoo thе valuе сrfеvolutiоnar In his сontriЬutions tr nеar-photogrаphiсmеm inсludеd morе than 750 сatеgoriеs:systеmatiсs,h In systеmatiсs Simpsо sions dеsignеd to Ьеttеr s p е с i е s .Т h i s w o r k с u | m mals, fossil and living. Tl Ьгеаdth and dеpth tlf knt prеsсriЬеd mеthods for g of multidisсiplinary kno. somеthing for thе taхOn flесt еvо|utionary histor1 сompеting сamps in taхс n o m i с n a m е sа r t саl r r а n g е v o l u t i o n а r yr с I a t i o n s h Ь | еа n d i n d е p е n d е not f е points with nеwеr appro Simpson trainеd at a ti сludе thrее kinds of phе rangе' and сhangе in есo foсus oГ histrlriсаЬ l iogе many studiеs t() traсе с] timе. Hе с
Simpsoп Prоgrеssiп Еuolиtionаrl

tsiologу.

.editу, London: Нutсhinson.

-М.R.

)84) pаlеontologistalld :rn ехpеrt on :iЬutionsto еvo1utionarythеory, Ьuilt lasting links Ьеtwееn palеrdеd thе Univеrsitу of Colorаdo sm аnd litеraturе Ьr-rtdisсovеrеd elr.To dеvеlop this intегеst Simph е r еh е е a r n е da P h B ( 1 9 2 З ) a n d first foсusеd on mammals that l Sirnpsсlnspеnt a уеar in Britain mе nl:rmmals hеld in Еuгopеan Nаtural History in Nеw Yсlrk in on rеplaсеd his mеntor, William t еstееm.Thе \mеriсаn Musеum ts of vеrtеЬratеfсlssils. Simpson tе thе Grеat Dеprеssion. Patrons [n Nсlrth Amеriса Simpson сolll as aсross thе еntirе Southwеst. zil, and Patagоnia. Simpson аlso s rеfusеdhim pеrmission for pol a rеputation for Ьеirrgan armo trаvеl and spеnt a signifiсarrt ions. Hе was a pror.ldmеmЬеr of hе advеnturеof travеl. sеrviсеand sеrvеdin military in'luеnt in kеy languagеs,inсluding }sonWas idеal for suсh work. Irr viсе allowеd him to еsсapе a сrirm. Its dirесtor' AlЬегt Parr, had .еoгganizatiоnthе palеontology l n t i q u a t е d a n d u n s l t i t a Ь l еf o r а lсеаnоgraphеrаnd ',vantеdmorе in 1944,сoolеr hеads prеvailеd. r p p o i n г е dh е e d o i г h е r е t l r g a n i z hilе on an ехpеdition in Brazil. еxpеdition work asirin. Friеnds ronе сlf his writing аftеr thе ассi-

dеnt matсhеd Ьis еarliеr Ьrillianсе. Whilе hе was inсapaсitatеd,Simpson fеlt llЬandonеd Ьy сollеaguеsat thе Amегiсan Мusеttnr.Тhе rеsultirrgrifts Iеd to his rеsignationin l9.59 аnd a mtlvе to thе Мusеum of Сomparativе Zoo1ogу (МСZ) at Harvard Univеrsity. Although his nеw сollеaguеsinсludеd somе of thе most importаnt еvolutionary Ьiologists of thе day (notaЬly Alfrеd Romеr, .!7ilson), ЕгrrstMayr, Bryan Pattеrson'Arthttг Сrompton, and Е' O. Sirrrpson largеl1,ц,,оrkеdaltlпе. Hе dеspisеd tеасhing аnd Ьad fеlv str-rdеnts' Siпrpson fсlrmallyrеtirеd ln 1982 and diеd in 1984. Simpson mаrriеd twiсе. Нis first marriagе, to Lydia Franсеs Pеdroja (1899_1988),produсеd fouг сhildrеn, Ьut thе marriagе nеvеr Ьlossomеd.For morе thаn а dесadе thе сouplе fougЬt Ьittеrly ovеr сustody of thеir сhildrеn. Divогсе сamе in 19.]8. During this tiпrе Simpson dеvеlopеd а rеlationship with Annа (Arrrrе)Мiriam Rое (1904_1991'),a сlrildhood friеnd. R
8.'9

8(l0

Simpsoп for mеasuring Ьiogеographiс сhangеs.Hе also proposеd a sеriеsof thеorеti. сal idеas for tеsting whеn еxplanations wеrе nееdеd.On similar linеs, Ьеginning in thе 1930s, Simpson sеvеrеlyсritiсizеd thе thеory of сontinеntal drift. Hе thоught that thе fossil rессlrd for mammals Was Ьеst еxplainеd Ьy thеo' riеs of migration aсross land Ьridgеs. Hе kеpt this viеw until thе 1960s, whеn еvidеnсе for sеaflсlor sprеading сonvinсеd him that сontinеnts wеrе moЬilе. Simpson is Ьеst known for his studiеs of еvolutionary proсеssеs.Tempo апd Мсlde iп Еuсllutiс.lп(\944), rеvisеd in 1953 as Маjor Fеаturеsof Еuolutioп, gaioed instant rесognition for its novеlty and sсopе. Horses (1951) appliеd his thеoriеs to a spесifiссasе (sееfigurе).In thеir ovеrall аpproaсh thеsе Ьooks Ьrought togеthеr gеnеtiсs' Ьiogеography,есology, аnd mathеmatiсal modеling of populations to produсе a gеnеral undеrstandingof еvolutionary pattеrns and proсеssеs.Thеsе Ьooks Ьесamе еssеntial rеading for sеvеrаl gеnеrationsof еvolutionary Ьiologists. Sсlmе'howеvеr' сritiсizеd him for ехсеssivе spесulation.For palеontolоgy Simpson introduсеd somе of thе latеst dеvеlopmеnts in gеnеtiсs and statistiсs' Не wantеd to rеshapе thе way his

Аdapfire

phasе

с o l l е e g u е rsh o u g h tа Ь o lutionary сhangе popt w а n t е d t o s h o w г h еi m p ary phеnornеnaand for t s} with orhеr Ьiо|ogistw r е с е n t i n n o v a t i с l n si n t Еrnst Mayr, and Julian thеir movеmeпt a mсldе though Simpson prеfеr o n s i m i l а r l i n е si s S i thе surfaсе this is a gеnе а г е d i s с u s s i o n sr l f е v o l This Ьook сlеaгly show and its аftеrmath. It сl Ьloody сonfliсt and aftt asks, сan Ье lеarnеdaЬс w a s w i d е l y d i s с u s s е da r In thе 1970sSimpso ogy. Advoсatеs of punс N i | е s Е l d r е d g е .p r е s е n m i s l е dp a l е o n r o l r l g i s rr ual rаthеr thаn rаpid., гraсtors polаrizеd pe|ес е аmЬitious younЕ]stеrs simply takеn а fеw of h to hidе thеir laсk of еv w е l l а f t е r h i s d е а r h .Т h is rеmemЬеrеd. B|вLloGRAPнY

Prеadaptive phase

Inadapfivс phase

I quartu-4 G. G. Simpson adaptеd \Vright's adaptivе landsсаpе mеtaphсlr, rеading it in tеrms of groups of lсlng-gtlnеorgаnisms (rathеr than gеnеs) tо shсlw how horsеs еvolvеd from Ьrowsеrs to grazеrs (aftеr whiсh point' nоt shоwn hеrе, thе Ьrowsеrs Wеnt ехtinсt). (From Simpson 1944'208.)

C а i n ,J . l 9 9 2 .B u i l d i r lаgt е duringan Amеriсrrn Lаportе,L. 2000.Gеorgе York: СolumЬiaUrri S i m p s о nC. . G . I 9 4 4 . Т с Prеss. LJnivеrsity 1945.Тhе prirrсi B ц l l е t i п , ' tf h с А m е r

|949' Тhс Мсапtt S i g п i | i с а п с с [ ,l r М а l l .

| 9 5 1 , H о r s e s :Т h ThrougЬ Siхtу Мilliо, 195З. Маjor Fеаt |97B.Сt tпссssio Nеw Harсn, СT: Yа| Simpson, G. C., and A. Rr \X/hittington,Еl. B. 1986. I-сlltltusllI IIlс Rl5,ll

Ьlmpsoп rlso proposеd a sеriеs of thеorеtiе nееdеd.on similar linеs, Ьеginеd thе thеory of сontinеntal drift. nals was Ьеst ехplаinеd Ьy thеokеpt this viеw until thе 1960s, vinсеd him that сontinеnts Wеrе ,f еvolutionary proсеssеs. Tеmpo 953 as Маjor Fеаturеs of Еuolu.lty and sсopе. ЁIorses (1951) apе). In thеir ovеrall approaсh thеsе rphy, есology, and mathеmatiсal :al undеrstandingof еvolutionary mе еssеntial rеading foг sеvеral е. howеvеr. сritiсizеd him for ех;on introduсеd somе of thе latеst : wantеd to rеshapе thе way his

Аdapfire Phasе

соllеaguеsthought aЬout fossils,and hе rеjесtеdsеvеralеxplanations for еvolutionary сhаngе popular in his disсiplinе. T
Prеadaptive phase

Inadaptive phase

I s с а p еm е t а p h o rr. е a d i n gi t i n :r than gеnеs)to show how horsеs point' not shown hеre, thе 2 0 8 .)

Cain' J. 1992.Buildirrgа tеmporalЬiсllogy:Simpson'sprogrапrfor palеontology Historу 11:З0_36. duringan Amеriсanехpansionof Ьiology.Ь,аrthSсiеltсеs I-apсlrtе, L. 2000. GесlrgeСауktd Simpsott:Pаlеoпtolсlgist апd Еuolиtiorisf.Nеw York: СolumЬiaUrrivеrsity Prеss. Simpson,G. G. l944. Tеmpoапd Мtldе iп Еuсllutioп.Nеw York: СolumЬie UnivегsityPrеss. of mammals. 1945.Тhе prinсiplеsof сlassifiсation and a сlassifiсаtion Bullеtiп of thе Аmеricап Мuscum of NаtиrаIHistorу 85: i-хvi, 1_350. |949. Тhе Меапiпg of Еuolutklп:A Studу of thе Нistorу of Lifе апd of Its Sigпifiсаnсеfor Мап' Nеw Havеn, СT: Yalе UnivеrsityPrеss. 1951.Hсlrsеs:Тhе Storуof thе Нorsе Fаmilу iп thе Мodеrп Wсlrldапd Thrtшgh SiхtуМillkп Yеаrsof Histl;ry. Nеw York: Oхford UnivеrsityPrеss. 1953.Маjor Fеаturеsof Еuolutioп.Nеw York: СolumЬiа UnivеrsityPrеss. Autobiсlgrаphу. |978. Сoпсеssioпto thе Improbаblе:Аll Uпссlпuеlltiсlпаl Nеw Hаvеt-t, СT: Yаlе UrrivеrsityPrеss. Nеw York: МсGraw.Hill. Sirrrpsor.r, G. G.' and А. Rсlе.1939.QuапtitаtiuеZ<хlklg1'. .W.hittington, FI. B. 1986. (iеoгgеGaylord Simpsсln.BiogrаphiсаlМеmoirs of Fеlloшsof thе Roуаl Soсictуtlf I,oпdoп 32: 527_5З9. -I .С.

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Soсiаl Dаrш'iпism

Soсial Darwinism Soсial D:rгwiIrism is сottr,еntionallyсlеfinеdas thе аppliсаtiсlrrсlf Dаrwirr's thеory of natural sеlесtiorrto thе domаin of hurтan аffairs. Тhе tеrm is usеd to dеsсriЬе soсial, raсial, and moral thесlriеs,as wеll ils есonсlmiсand politiсal onеs. Мost сommonly it rеfеrs to tlrеoriеs that ас]voсаtеa glirdiatorial strugglе fс>rехistеnсе, in whiсh thе losегs сlеsеrvеttr ltlsе and srrгvivаlЬесomеs proof of mеrit. Tlris dеfinitiorr,hсlwеvеr'doеs nсlt сtrrrеspondto his. toriсal rеality and rеquirеs furthеr сlarifiсаtion. Soсiаl Darwinisnr is a сomplех сonсеpt. Its signifiсanсeсhangеd ovеr timе аnd aсross gеographiсЬt>rdеrs, aсquiring rеmarkaЬ1ydiffеrеnt rтеanings. It is iпrportаnt to notе that soсi:rl Darwinisrrr is rrot thе irnrnеdiаtеotfspring of D:rгwin's Ьiologiсal thеoriеs. Although Darwin somеtimеs ехprеssеd viеws that sееm сonсordant with positions hеld Ьy somе soсiаl Darwinists (his dеsсription of raсial strugglеsas purrtсlf soсiаl еvolution in Thе Desсеltt of Мап is сlnе suсlr ехаmplе), lris main intегеstdid not liе in soсiаl or politiсal thеorizirrg.Furthеrnrorе' attеmpts tсl draw parаllеls Ьеtwееn human еvolution and thе еvolution сlf soсiеty as part of аn еffort to justify сеrtain politiсal doсtrinеsprесеdеdI)arwin's Оn thе Оrigiп of Spесics(1859). HеrЬеrt Spеnсег, for instаl-lсе'who ссlitlес1thе ехprеssitln ,.survivаl of thе fittеst,''puЬlishеd еssa},sЬеforе 18.59irr whiсh hе сlirimеd that dеvеlopmеnt (i.е.,еvolution) was thе univеrsal law ot pгogrеss.Hе usеd this idеа to arguе in favor of frее есonomiс сompеtition Ьеtwееnindividuals аnd to sllpport thе idеology of laissеz-fаirеliЬеrаlism. This lrаs lеd somе sсl-rolarsto dесlаrеthat soсial Dаrrvinism wсlr"rldЬе morе ассurаtеly trаtnеd soсial Spеnсеrisnr. Spеnсеr'sЬiology, thouglr, was mainlу inspirеd Ьy Jеаn-Baptistе Lаmarсk's transformism. Whеthеr attriЬutеd to D;rrwin or to Spеnсеr, sо-саllеd soсial Dlrrwinism сlеаrly plаyеd a major гolе in thе sЬaping of сlisсiplinеsс]сс]iсatеd to thе study of humankir-rd:anthropology, еthrrolсlg,v, and soсiology' [n сlrdеr to Ье сonsidеrеd sсiеntifiс' thеsе soсiаl sсiеnсеs dгеw on Ьiologiсal notions. Human raсеs, сulturеs' and pеoplеs Wеrе сomparеd with spесiеsand wеrе сorrsidегеdsuЬjесt to thе samе natural laws of strugglе,adaptation,аnd survival.Thеy rr.еrеoftеn aггangеdorr a kind of еvoIшtionarysсirlеthаt indiсirtеdthеir dеgrееof progrеss. Thе works оf Amеriсan soсiologist \yr'illiamGrahanl Sumnеr, British аnthropologist Е. B. Tylor, and Frеnсh raсial thеоrists Gustavе L,е Bon and Gеorgеs Vасhеr dе Lapougе arе a fеw ехamplеs of this typе of .rpproaсh. Frarrсis GaltonЪ еugеniсs, whiсh hе tеrmеd thе sciеttcесlf btnnап bеttеrmaпt,сan аlso Ье сlassifiеd urrсlеrthе IaЬеl of s
тzol

Еvolution aftеr Dаrwin s pеoplе'sprеjudiсеs.Almr likе. This саrtoon,fгom i n s u I tЬ y h а v i n gа s : rс а p aЬout thе Afriсans (Ash

istll, it wаs harnеssеdto nations or to lеnd suppс Т h е s е g I a d i a t o r i ailr а u t о m a t i с а I l yo, r i n f u l pсlsеd nrilitarism' whiс t r a r y t ( ) l a i s s е z - Г e i гpеt l Ьiology and Spеnсеr'sp thаt wеrе rhе ехaсt t-l n a m е I 1 .s,t l с i а l i s mс. o | сonnесtion ЬеtwееrrD; l 8 6 l , i n а l е t t е rt о F е r с suits my purpсlsеin t|ra iсal сlass strugglе'' (Nl

Sociаl Dаrшinism

as thе appliсatiсlrrof Darwin's human affairs. Тhе tеrm is usеd ' as wеll as есonсlmiс and politiiеs that advoсatе а gladiatoгial lеsеrvеtс, losе and strrvival Ьеvеr, doеs not сorrеspond to hisr. Soсial Darwinisr-nis a сomplеx d асrossgеographiс Ьordеrs, aсnism is not thе immеdiatе offг h o u g h D а r w i n s с l t t t е г i m е еs х pсlsitions hеld Ьv somе soсiаl ]s as part of soсiаl еvolution in is main intеrеstdid not liе in so]mptsto draw parаllеls Ьеtwееn :у as part of an еffort to justify Эп thе Оrigiп of.Spесiеs(1s59). tlrе ехprеssion ..survival of thе сh hе сlaimеd thаt сlеvеlopmеnt 4rеss.Hе usеd this idеa to aгguе n individuals аnd to suPрort thе еd somе sсholars to dесlaге that .еIt nаmеd soсi.rl Spеnсеrism. rеd Ьy Jеan-BaptistеLаmarсk's с е r , s о - с а I | е ds o с i a I D а r w i n i s m lisсiplinеsdеdiсatеdto tlrе studv soсiology.In ordеr to Ье сonsid'iologiсalnotions' Humarr гaсеs, сiеs аnd wеrе сonsidеrеdsuЬjесt n, and survival.Тhе1,wеrеoftеn -rdiсatеdthеir dеgrее of pгсlgrеss. ]rahаm Sumnеr, British аnthro. its Gustavе Lе Bon and Gеorgеs ; rypе of approaсh. Franсis Gal, hutпап bettеrmепt,сarl also Ье Гhеsеthеoriеs and otl-rеrssimilаr ,tl ilnd есоnomiс thouglrt. Thеy r l r I i t i еas n d с u r г h г o а tе с o n t l m i с rnеgiе and John D. Roсkеfеllеr tmеnt and Ьusinеssmonopoliеs ;urvivalof thе fittеst.Soсial Darгy ilnd disсriminationalld to fuеl :).With thе grorr.th
Еvolution аftеr Darwin suссееdеdin largе part Ьесаusеit so rеadily lеnt itselfto pеoplе'sprеjudiсеs'Almоst inеvitаЬll, сartoonistsPoгtrayеdthе Irish as aPеIikе.This сartoon,frtrrlrthе pсlprrlarrrrаgаzinе Рuсk (|882), сompoundstЬе insult Ьy having21sа сaption ..Кirrgof A-Shanty'''thus Ьringingin аttitudеs аЬout thе Afriсarrs(Ashantееs)аs wеll.

isrn, it was harnеssеdto Warrant thе tlsе of military powеr in сonfliсts Ьеtwееn nations or rсl lеrrd support to f:rsсistand Nazi idеologiеs. Thеsе gladiаtсlrial intеrprеt:rtionsof еvolutiсlnаry Ьiology do not apply automatiсally,or in full, to all ..soсialDаrwinists.'' Spеnсеr,for ехamplе, opposеd militarism, whiсh hе rеgаrdеd as a fсlrm of statе intеrvеntion' сontrаry to laissеz-fаirеpolitiсs. Мorе important' mаny thinkеrs usеd Dаrwin's Ьiology аnd Spеnсеr'sphilosophv to pгovidе sсiеntifiсlеgitimaсy to doсtrinеs that wеге thе ехaсt opptlsitе of fгее-markеr liЬеralism and individualism, namеly, soсialism, сollесtivism, end Marxism. Мarх himsеlf drеw a сlosе сonnесtion Ьеtwееn Darwin's thеory and his own doсtrinе аnd dесlarеd in l861, in a lеttеrto Fеrdinаnd l-asаllе,..Darwin's work is most important and suits my purposе irr tЬat it providеs a Ьasis in thе naturаl sсiеnсеfor thе historiсаl сlass strr-rgglе''(Мarх |985,246-247). L,atеr somе soсiаlists, likе thе

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Soсiаl Dаrшinism Italian Еnriсo Fеrri, insistеd сlп thе intimatе сonnесtioIlЬеtwееnDarwinism, Spеnсегism, and Мarx's sсiеntifiс soсialism. othеrs, likе anаrсhists Еmilе Gautiеr and Prinсе Pеtеr Kгopotkin, arguеd that thе шOst important law in еvolutionаrгyЬiology Was not tlrе strugglеfor ехistеnсеbut mutuаl aid. ]n thе Unitеd Statеs,soсiаlist Hеr-rryGеorgе assignес1 an iп-tpсlrtatrt r()lеto еtrvironmеntal сonditions in dеtеrnrining thе сoursе of progrеss and arguеd f
L a n е s s a n J, . - l - .d е . 1 8 8 1 Еtпdе sur lа dосtriп' Мarх' K' |985. Каrl Ма еt al., tг;tns.Nсr'',Yс Pittеtrgеr,N7. 799З. Amс Маdison: Univеrsitу SirrgеrP. 20ОО.А Dаrшi, СТ: Yalе Univеrsity

Sociobiologу: Thе

Srl сiob iсllogу : Тh е Nеt Wilson, lvаs puЬlishе with Thе lпsесt Srlсitlt Prizе-winning Ьooks, givеs an ovеrall piсtur sidеrеd from a Darwir natrrral sеlесtionto Ье mals in soсial situatio l.lrе first part of thе tioгl Ьiоlogv, with spе rlс.ltiorrof аltruistlt. \,Y

ехistеnсе,do not alwl s()ll1еtimеsshow сoop, thе bееs,and thе wasp nеw thеorеtiсаlmodеl what had Ьесomе knо duсtion of othеrs whеr is disсtrssionalso of o titln; lrrost signifiсantl саls usеd сarry inforrr Thе sесondhalf of thе slimе molds throu rтammals and thеnсес Out own spесiеs,Hoи Hе fесls that thе most Wе cеt a rеlaхingof s hutrrаnssееm somеho сiаl bеings that har,еb fr.rnсtionof thе spесi ability. To еxplain humans\

T h i s s u p p o s е st h a t t h ( lo'"l,shuman еvсllution titln fееds into thе wh. сhаngе. Thе movе to b to tO()lntanufaсtLtrе'

SoсioЬiology

ltе сonnесtion Ьеtwееn Darwinism, ism. othеrs, likе anarсhists Еmilе lеd that thе most important law in for еХistеnсеЬut mutual aid. In thе g n е d a n i m p o r t a n гr o l е t o е n v i г o n oursе of progrеss and аrguеd fol riеws and thе сampaign hе lеd for : support of Alfrеd Russеl $Иallaсе, :tion. Toward thе turn of thе twеnvеrsion of Darwinism as thе doсmе thе prеdominant idеology of thе rrism, and thе Ьаsis of its wеlfarе ,nе of thе main Ьuilding Ьloсks in ; еarly formulation. 1tеrprеtеdto srrpport vеry diffеrеnt nеnts Was сonsidеrеd thе most imэst Werеviеwеd as thе main ()pеrat. suppоrt right-wing doсtrinеs. But mесhanismsof soсial Ьеhavior suсh tg faсtors,еvolution сould Ье intеrl as soon as thе thеoriеs thеmsеlvеs эamе from onе of thе Е]rеatеstеxpo. еnry Huхlеy. Hе oЬjесtеd that onе 'om naturе's workings, a movе that ed tЬe паturаlistiс fаllаcу, Yеt soсial Ltеdеntеrprisе.Proqrеss madе in gееriсan еntomologist Е. O. \7ilson to is, soсioЬiology. It was prеsеntеd as vior through Ьiоlogy. In есonomiсs, 'еmptеdto show thе сoгrеlation Ье:еt сapitalism.on thе othеr еnd of \ Dапuiпiап Lеft (2000) is еvidеnсе arwinism havе also not gonе out of :rеntfrom Darwin's timе and muсh rdеrstandingthе wаys in whiсh hutill vеry muсh a сontrсlvегsialissuе.

эсеаnd Муth iп Апglo-Amепсап vеrsityPгеss' : Univеrsityof ТеnnеssееPrеss. . Univеrsit1,: Univеrsityof AlaЬаma аm, U.K.:opеn UnivеrsityPrеss. Thought,Brighton,U.K.: Hаrvеstеr

L a n е s s a n , . j . . t - . d еl .8 8 1 . D e l а l u t t e p o u r l ' е х i s t е | 1 с е е t l ' а s s o с i а t i o п p с l и r l а l u t t e : Еtudе sur lа drlсtriпе dе Dаrшiп. Pаris: oсtavе Doir.r. Marх, K. 1985. Kаrl Маrх, Frеdеriсk Епgеls: Сollесtеd Wrlrks. Vol.41. R. Dixon еt аl.' trans. Nсw Yоrk: lntеrnational Publishеrs. Pittеngеr,M. 1993. Amеriсап Sсlсiаlistsапd Еurllutitlпаrу Thought, 1870_1920. Madison: Univеrsitу оf Wisсonsin Prеss. Singеr P. 2000. А Dаrшiпiап Lеft: Politiсs, Еuoltttioп аnd Сooреrtаlotl. Nеw Hаvеn, -N.8. CТ: Yriе Univеr'ityPrеs'.

Soсiobiologу: The Nеul Sупthesls (Еdward o. Wilson) Soсiobiologу: Тhе Nеш Sупthesis, by thе Harvard еntomologist Еdward o. \й/ilson,was puЬlishеd in |97 5.It wаs thе сеntеrwork of а trilogy that Ьеgan witЬ The Iпsесt Sсlсiеties(1'971) and еndеd with thе first of Wilson's Pulitzеr .Wilson Prizе_winning Ьooks' Оп Humап Nаture (\978). In Sociobiology givеs an ovеrаll piсturе сlf thе growing fiеld of аnimal soсial Ьеhavior' сonsidеrеd from а Darwiniаn pеrspесtivе'that is, from a pеrspесtivеthat takеs nаturаl sеlесtionto Ье thе kеy сausal сomponеnt Ьеhind thе Ьеhavior of animals in sсlсialsituations. Thе first part of thе Ьook dеals with mесhanisms:thе workings of population Ьiology, with spесial еmphasis on what Wilson dесlarеd to Ье thе kеy ntltitln of аltruism. Why and how is it that animals' forgеd in thе strugglе for .sИhy do thеy ехistеnсе, do not always fight and сompеtе in a Ьrutal way? somеtimеs show сoopеration, most oЬviously in thе hymеnoptеra (thе ants, thе Ьееs,and thе wasps)? To answеr thеsе quеstions.Wilsonintгoduсеssomе nеw thеorеtiсal mсldеls,еspесially thosе of \Хiilliam Hamilton that foсus on what had Ьесomе known as kin seleсtiсlп, wЬere animals hеlp in thе rеproduсtion of сlthеrswhеn thеsеothеrs sharе thе samе gеnеsas the hеlpеr.Thеrе is disсussion also of othеr issuеs, partiсularly modеs of animаl ссlmmuniсation; most signifiсantly'hе highlights thе importanсе of phеromonеs (сhеmiсals usеd сarry information). Thе sесond half of thе book survеys soсial Ьеhavior in оrganisms from thе slimе molds through thе soсial insесts and nехt thе vеrtеЬratеsto thе mаmmals аnd thеnсе on to thе so-сallеd highеr apеs. Thе final сhaptеr is on our own spесiеs,Homсl stlpiепs' !Иilson sееs a paradoх in animal soсiality. Не fееls that thе most intеgratеd soсial beings arе thе slimе molds, and thеn Wе gеt a rеlaхing оf soсial Ьеhavior as Wе movе up thе аnimal сhain. Yеt humans sееm somеhow to havе rеvеrsеd this' Ьесausе wе arе thе most sосial Ьеings that havе Ьееn sееn on this planеt. Сiеаrly this is in major part a funсtiсln of thе spесiаl adаptations that wе havе, for instanсе, languagе aЬility. To ехpiain humans \Wilson introduсеs what hе сalls thе autoсatalysismodеl. This supposеsthat thеrе is a сеrtain thrеshold lеvеl that, onсе Ьrеaсhеd' allows human еvolution to proсееd muсh morе rapidly Ьесausееaсh innovation fееds into thе wholе and (oftеn through fееdЬaсk)spееdsup thе ratе of сhangе.Thе movе to Ьipеdalism сoinсidеntally frееd up thе hands, whiсh lеd to tool manufaсturе' whiсh lеd to mеntal еvolution, whiсh lеd to inсrеasеd

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Spenсer сoopеration in hunting, whiсh lеd to a сhangе of diеt (morе mеat and hеnсе thе potеntial for Ьiggеr Ьrains), and to othеr fеaturеsand aЬilitiеs that Wе аssoсiatе with modеrn humans. .Whеn it was puЬlishеd, $Иilsсln'swork was high|y сontrovеrsial. Сritiсs from thе soсial sсiеnсеsfеlt thаt hе was insеnsitivеto thе nuanсеs of human сulturе, and сritiсs from thе Lеft aссusеd him of simply promulgating a сonsеrvativе' patriarсhal viеw of humankind, drеssеd up to look likе sсiеnсе. Partiсularly сritiсal Was a group that wеnt undеr thе namе of Sсiеnсеfor thе Pеoplе. Opinion dividеs ovеr whеthеr thе сhiеf еffесt of thе сritiсisms was to .Wilson's position or to inсrеasе his Ьсlok salеs. Today' morе than dеstroy thrее dесadеs latеr, Soсiobiologу is rightly sееn аs onе of thе landmarks of еvolrrtionaryЬiology, taking its plaсе alongsidе thе grеat works of thе еarliеr .!7ilson part of thе twеntiеth сеntury. Thе faсt thаt disсussеs humans is сonsidеrеd no anomaly, Ьut somеthing thаt has Ьееn donе Ьy almost еvеry grеat еvolutionist sinсе Сharlеs Darwin (and Ьеfore).In mаjor rеspесts'morе intеrеsting than thе mеrе fасt that humans arе disсussеd is that thеy arе usеd .!7ilson's firmly to support Ьеlief that thеy arе thе apothеosis of еvolution, thе suprеmе point of thе progrеss that thе dеvеlopmеnt of lifе has shown through thе agеs. Thцs Iй/ilson opеnеd thе way for his latеr, morе opеnly philоsophiсal works, likе oz I{иmап Nаture andThе Сrеаtion (2006), whеrе hе has proposеd ехpliсitly that what hе сalls thе ..myth'' оf еvolution (Wilson 1978, 192) rep|acethе outmodеd story of Christianity. For }7ilson, his sсiеnсе hаs always Ьееn part of a biggеr mеtaphysiсalpiсturе. в|вLIoGRAPHY Rusе,М. |996. Мoпаd to Мап: Тhe Сoпсeptсlf Progrеssiп Еuolutklпаrу Biсllсlgу' СamЬridgе,MA: Harvard UnivеrsityPrеss. Sеgеrstralе, U. 2000. Defепdеrsof thе Truth: Thе Bаttlеfor Sсiепсеiп thе SociobiolсlgуDеbаtеапd Bеусlпd'Nсw Yоrk: oхford UnivеrsityPrеss. .Wilson, -ГЬe Е. o. 1971. IпsесtSoсiеtiеs.СаmЬridgе'МA: Наrvard UnivеrsityPrеss. \975. Soсiobiologу: Thе Nеш Sупthсsis. CаmЬтidgе, МA: BеlknapPrеssof Harvard UnivеrsityPrеss. 1'978.Оп Humап Nаturе. СamЬridgе,MA; Нarvаrd UnivеrsityPrеss. 2006. Тhе Сreаtioп:А Мeеtiпgof Sсiепсeапd Rеligk п. Nеw York: Norton. -л{.R.

Spеnсеr,Hеrbеrt (1820_1903) HеrЬеrt Spеnсеr was a British philosophеr and onе of thе most influеntial thinkеrs of thе Viсtorian agе. A man of есlесtiс intеrеsts, Spеnсеr wrotе on suсh divеrse topiсs as physiсs, Ьiology, psyсhology' еduсation, musiс, aеsthetiсs, and rеligion. Не is, howеvеr, mostly known for his attеmpt to сonstruсt a сomprеhеnsivееvolutionary thеory of progrеssin naturе and soсiеty. Spеnсеr rесеivеd littlе formal еduсation.Hе was mainly taught аt homе Ьy his fathеr and his unсlе and startеd working at age 16 as a сivil еnginееr for a British railway сompany. Although his talеnt and mесhaniсаl invеntions

promisеd suссеssin th twеntiеs and turn to jo h o w p a s s i o n a t е l yh е с a a sеriеstlf lеttеrstitlеd Noпсoпformlsl in ] 84 philosophiсal systеn-rh' that appliеs to Ьoth in thеrе is a Ьiosoсiаl сon Ьy mеans of growing с providеd an outlinе of l еralism and сlpptrsеdаr thе frее сoursе of natu justiсе. This position r most of Spеnсеr'ssсiеn In aссordanсеwith h ( 1 8 4 8 * 1 8 5 3 a) s s u Ь е d mist. Аpart frсlm a fеr Unitеd Statеs,Spеnсеr his еngagеnrеntwith tl hе had a vеry intimat h a v е h o p е d .T h i s w a s t Thomas Hеnry Htrхlе him to thе famous Х сl Thе work fоr thе Ес first Ьook, Soсiаl Stаtiс сiplеs of a pr.rrеlysсiеn numЬеr of artiсlеs,notl favour of Lanrarсk's t] Ьoth puЬlishеd in 18.5 RoЬеrt Мalthus, Spеnс сamе vеry сlosе to еnur Russеl !Иallaсе's natur grеat satisfaсtiсlrrwith еmphasis on thе law o did. This Lаmаrсkian l сhaniсally сausal rеla morе in tunе with Spе not allow random mut: gardеd natllral sеlесtiо dеfinеd еvolution as tht еnt hеtеrogеnеity,a pr nесеssаryprogrеss.Da grеssivеdеvеlopmеnt.l naturе and oЬjесtivеso ologist.Spеnсеr'sultim:

S1lеnсer 867 gе of diеt (morе mеat and hеnсе fеaturеsand aЬilitiеs thаt wе as',as highly сontrovеrsial. Сгitiсs nsitivе to thе nuanсеs of human n o f s i m p I уp r o m u | g а t i n 8a с o n lrеssеdup to look likе sсiеnсе. ndеr thе namе of Sсiеnсе for thе iеf еffесt of thе сritiсisms Was to book salеs. Today' morе than iееn as onе of thе landmarks of dе thе grеat works of thе еarliеr W i I s o nd i s с u s s е sh u m а n s i s с o n Ьееn donе Ьy almost еvеry grеat ' r е ) .I n m a j o r r е s p е с r s ,m o r е i n э disсussеdis that thеy arе usеd : thе apothеosisof еvolution' thе pmеnt of lifе has shown through s latеr, morе opеnly philosophiСrеаtioп (2006), whеrе hе has yth'' of еvolution (Wilson 1978' -rity.For lWilson, his sсiеnсе has сturе.

)rogrеssin Еurllutiсlпаrу Biсllogу. Bаttlеfоr Sciепсеiп the : Oхftlrd UnivеrsiгyPrеss. lgе,МА: HаrvardUnivеrsityPrеss. 3amЬridgе' МA: BеlknapPrеssof A: Нarvard UnivеrsityPrеss. l апd Rеligion.Nеw York: Nоrton. -44.R.

rnd onе of thе most influеntial сtiс intеrеsts' Spеnсеr Wrotе on . . h o I o g yе' d u с а t i о n ' m u s i с , a е s known for his attеmpt to сonf progrеssin naturе and soсiety. е was mainly taught at homе Ьy at age 16 as а сivil еnginееr for l е n t a n d m е с h a n i с а |i n v е n t i o n s

promisеd suссеss in this fiеld, hе dесidеd to quit thе profеssion in his midtwеntiеsand turn to journalism and pоlitiсal writing. Еarliеr Spеnсеrshowеd how passionatеlyhе сarеd aЬout politiсs with his first important puЬliсаtion, ..Thе Propеr Sphеrе of Govеrnmеnt,'' puЬlishеd in thе a sеriеsof lеttеrstitlеd Noпсcпformisl in 1842. Thеy еnсapsulаtе thе kеy еlеmеnts of thе grеat philosophiсal systеm hе latеr dеvеlopеd:Ьеliеf in a univеrsal law of progrеss that appliеs to Ьoth intlгgаniс and оrgarriс пIattеr, and thе сonviсtion that thеrе is a Ьiosoсial сontinuity that links nаturе' human Ьеings, and soсiеtiеs ..Thе Propеr Sphеrе of Govеrnmеnt'' also Ьy mеans of growing сomplеxity. providеd an сlutlinеof Spеrrсеr'spolitiсal сrеdo. Hе dеfеndеdlaissеz-fairеliЬеrаlism and opposеd any fсlrm сlf govеrnmеnt intеrvеntionthat would hindеr thе frее сoursе of nаturе othеr than Ьy maintaining ordеr and administеring justiсе. This positiсln rеmainеd praсtiсally unаltеrеd thеrеaftеrand dirесtеd most of Spеnсеr'ssсiеntifiсwork. In aссordanсеwith his politiсal tеnеts' Spеnсеrgot a joЬ for a short pеriod (1848_185З) as suЬеditor for thе l,ondon-Ьasеdfinanсial wееkly tЬe Ессlпсlmist' А'part from a fеw travеls to thе Еuropеаn сontinеnt, Еgypt, and thе Unitеd Statеs,Spеnсеr spеnt most of his lifе in London. During thе timе of his еngаgеn-rеnt with thе Есoпomlsf, Spеnсеr mеt Gеorgе Еliot, with whom hе had a vеry intimаtе rеlаtionship, though not as intimatе as Еliot would havе hopеd. This was thе сlosеst Spеnсеrеvеr сamе to marrying. Hе also mеt Thomas Hеnry Huхlеy, who latеr Ьесаmе his сlosе friеnd and introduсеd him to thе famous Х сluЬ. Thе work for tlrе Есoпomist lеft Spеnсеr еnough frее timе to produсе his first Ьook' Soсiаl Stаtiсs (18.51), in whiсh hе еndеavorеdto sеt down thе prinсiplеs of a purеly sсiеntifiсsystеm of mсlrality. Hе followеd thе Ьook with а ..Thе Dеvеlopmеnt Hypothеsis,'' whiсh аrguеd in numЬеr of artiсlеs,notаЬly ..A Thеory of Population,,' favour tlf Lanrarсk's thеory of еvolution, and Ьoth puЬlishеd in 18.52.In thе lattеr, whiсh r,vasgrеatly inspirеd Ьy Thomas ..survival of thе fittеst.',Hе thus RoЬеrt Мalthr.rs,Spеnсеr сoinеd thе phrasе сamе vеry сlosе to еrrunсiatinga thеory similar to Сharlеs Darwin and Alfrеd Russеl \Х/allасе'snatural sеlесtion. But еvеn though Spеnсеr dесlarеd his grеat satisfaсtion with Darwin's Оп the Оrigiп of Spесies, hе plaсеd grеatеr еmphasis On thе law tlf inhеritanсе of aсquirеd сharaсtеristiсsthan Darwin did. Тhis Lаmarсkian lаw, with its undеrlying assumption of an аlmost mесhaniсally сausal rеlationship Ьеtwееn adaptation аnd еnvironmеnt' Was morе in tunе with Spеnсеr'sdеtеrministiс rеduсtionism. Indееd,Spеnсеr did not allow randсlm mutations thе samе еvolutionary powеr as Darwin and rеgardеd natural sеlесtion as only a sесondary mесhаnisnr of еlimination. Hе dеfinеd еvolution as thе pаssagеfrom an inсоhеrеnt homogеnеityto a сohеr. еnt hеtеrogеnеity,a proсеss that signifiеd for him lеngthy, сumulativе, аnd nесеssaryprogrеss. Dаrwin did not havе quitе thе samе сonfidеnсе in progrеssivеdеvеlopmеnt.Thе two еvolutionistsalsо diffеrеd сonsidеraЬly in thе naturе and tlЬjесtivеsof thеir еntеrprisеs.Darwin was first and forеmost a Ьiologist.Spеnсеr'sultimatеpurposе Wаs tO providе a widе-rangingеvolutionary

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5penсеr thеory that would aссount for progrеss in all domains and givе sсiеntifiс Ьа. sis to his politiсal and еthiсal individualism. As a rеsult hе foсusеd on thе study of soсiеty,whеrе his сontriЬution was m()stimportant. Spеnсеr еnvisionеd soсiеty as a nаtrrral organism, analogous to a living Ьody and subjесt to thе samе еvolutionary laws, with onе important саvеat. \Whilе in Ьiologiсal organisms thе еmеrgеnсе of a nеrvous systеm and thе dеvеlopmеnt of a Ьrain, whiсh funсtions as a сеntrаl rеgulating organ of thе Ьоdy, arе thе signs of a highly еvolvеd animal, it is not so for thе soсial or. ganism. It doеs not possеss a ..soсial sеnsorium'' thаt еxists аpart from its units (Spеnсer 7892,461). Soсiеty ехists оnly for thе Ьеnеfitof its mеmЬеrs, whosе individual сonsсiousnеssеsсannot Ье rеduсеd to somе сollесtivе ссln. sсiousnеss.Thе prеsеnсе of a сеntral сoеrсivе authority in thе soсial organ. ism is thus thе sign of a low phasе of еvolution, а transitory statеthat Spеnсеr tеrmеd tЬe militсlпt typе. As soсiеtiеs grow in dimеnsion, thе division of laЬor Ьесomеs morе importаnt аnd lеads to a prеdominanсе of thе industrial. есonomiс fасtor. Finally, thеrе is no longеr nееd for a сеntral govеrnmеntЬесausе industrial-typе soсiеtiеsсan аuto-rеgulatеthеmsеlvеsthrough systеms of produсtion and distriЬution. Spеnсеr'smost important puЬliсation, to whiсh hе dеdiсatеd most of his lifе as an indеpеndеnt writеr, is thе voluminous А Sуstеm rlf Sупthetiс Philсlsophу, puЬlishеd Ьеtwееn 1862 and 1893. It сomprisеs 10 volumеs and givеs a systеmatiсaссount of his viеws on mеtaphysiсs,Ьiology' psyсhology, soсiology, and еthiсs. TЬe Sуstеm сlf Sупthеtiс Philoso1lhу was a highly praisеd synthеsisof knowlеdgе, and in thе 1870s and 1880s Spеnсеr'srеpu.!fеistаtion rivalеd that of Darwin, Ьut his glory did not last long. August mann's attaсks on thе Lamarсkian prinсiplе of thе inhеritanсе of aсquirеd сharaсtеristiсsshook thе vеry foundations on whiсh Spеnсеr'sеvolutionаry еdifiсе was Ьuilt. His еfforts tсl dеfеnd his thеory еliсitеd littlе support, whilе nеo-Darwinian theoriеs' Ьasеd on thе pгinсiplе of natural sеleсtiоn,slowly Ьесamе thе prеdominant paradigm in thе fiеld. By thе first dесadе of thе twеntiеth сеntury it thеrеforе sееmеd that Spеnсеr had Ьееn provеd Wrong' and thеrе was no rеason to furthег invеstigatеhis systеm. It would bе a mistakе, howеvеr, to ovеrlook thе profound impaсt сlf Spеnсеr's idеas. A littlе сlvеr a сеntury ago hе Was onе of thе mоst influеntial writеrs in Britain, as wеll as aЬroad. His Ьooks wеrе translatеdirrto most Еuropеan languagеsand had a vеry largе сirсulation in thе Unitеd Statеs,whеrе his famе Was partiсularly grеat. Indian nationalists also hеld his thеoriеs in high еstееm,and in Jаpan hе was studiеd morе than any othеr fсlrеignwritеr. Within Spеnсеr'slifеtimе somе 1 million сopiеs of his Ьooks wеrе sold, and hе сountеd among his admirеrs pеoplе from many diffеrеnt fiеlds of study. .!7еstеrn Fеw pеoplе in thе history of modегn thought сan сlaim to havе had еqual suссеss.Еvеn at prеsеnt' thоugh thе man himsеlf may Ье disсrеditеd, his idеas still rеsonatе in сontеmporary frее-markеtthinking. Thеy thеrеforе mеrit sеrious attеntion. and indееd todav thеrе is a rеvival of intеrеst in Spеnсеr.

B|вLloGRAPHY

Franсis,ЬI' 2007, Herbеrt СornеilUnivеrsityPrе JonеsG , . ' a n dR . A . P е е l . Galton lnstitutе. P е е l J, . D . Y . 1 9 7 1 . Н е r b е BаsiсBoоks. Pеrrin,R. G' 1993.Нcrbе York: GarlandPublis Spеnсеr,LI. 1843.Tbе Pro l85 l. SосialSlatl Spесifiеdапd thе First 1852аT . hеdеvеl Rеprintеdin H. Spеn London:!Иilliams& l 1852b.A thеoryo fеrtility.Wеstmiпstеl 1892'Тhс Рriпсip T a y l o r ,М . W . 1 9 9 2 - .М а п lпdiuiduаlism.Nеw Y 2ОО7.The Philrlsr \й/iltshirе, D, I978. Тhе Sс Oхford UnivеrsityPге

Stanlеy,StеvеnМ.

Stеvеn М. Stanlеy is a whosе work is uniting р strating that palеontolo саnсе for undеrstanding primary thеorеtiсalсont thе formation of nеw s thе originator of thе thс lеgitimatе.unitsof sеlес to individual organism viеw is that thе history t of small сhangеs'a prеd tion. Rathеr, Stanlеy hal hiеrarсhy thеory-thе n disсontinuitiеsat intеrv assoсiatеdwith Nilеs Еl

еquiliЬria. Bеginning in thе mid had ignorеd thе impor rесord Ьy fосusing sol in individцal organism сhallеngеd thе nеo-D:

Stаnlе1,

domains and givе sсiеntifiс Ьa. As a rеsult hе foсusеd on thе most important. rganism, analogous ro a living 'ws, with onе important сavеat. of a nеrvous systеm and thе dе. сеntrаl rеgulating orgаn of thе ll, it is not so for thе soсial orium'' tlrаt ехists aрart from its . for thе Ьеnеfit of its nrеmЬеrs' г е d u с е dt o s o m е с t l l l е с г i v ес o n е authority in thе soсiаl organl' a trаnsitory statеthat Spеnсеr dimеnsion,thе divisiorr of laЬor :еdonrirranсеof thе industrialеd for a сеntral govеrnmеnt Ьеatе thеmsеlvеsthrough systеms vhiсh hе dеdiсatеd пrost
B|вLIoGRAPHY Frаt-tсis,|'4.2007. Hеrbеrt Spепссr аnL] thе lпuеntiсln o|-М
Stanlеy,StеvеnМ. (b. 1941) Stеvеn M. Stаrrlеy is a mеmЬеr.of an influеrrtial group of palеоntologists whosе work is uniting palеontology and nеontology (or Ьiology) Ьy dеmonstrating that palеrlntologiсaldata (likе thе fсrssilгесord) havе gеnuinе signifiсanсе for undеrstanding thе mесhanisms Ьy whiсh еvolution happеr-rs.Stanlеy's primary thеorеriсаIсontriЬutions havе Ьееn in thе arеa of maсroеvoltrtiоn'or thе formation of nеw spесiеs i1nd еvolutionary novеltiеs.Irr pаrсiсular hе is thе originator оf thе thеory of spесiеssеlесtion,whiсh holds th.rt spесiеsarе lеgitimatе units of sеlесtiоn and on а maсroеvolutionary lеvеl aсt analogсlusly to individual orgаrrismsin miсroеvolution. An inrportant impliсаtion of this viеw is that thе history of lifе has not Ьееn thе smotlth, сontinual proсrеssion of small сhan€ ] еs. а prеdiсtion dеrivеd from Dаrwin's theory of nаtural sеlесtion. Rathеr' Stanlеyhаs Ьееn an outspokеn supportеr of punсtuаtionismand hiеrarсhy thеory-thе notion that lifе's history h:rsЬееn Ьrokеn Ьy signifiсant disсontinuitiеsat intеrvals and on various lеvеls-whiсh arе most famously assoсiatеdwith Nilеs Еldrеdgе and StеphеnJay Gould's thеrlrу of punсtuatеd еquiliЬria. Bеginning in thе mid-]970s, Stanlеy arguеd that еvolutionary Ьiologists had ignorеd thе important lеssons that сould Ье lеarnеd from thе fossil rесord Ьy foсusing solеly on thе gradual aссumulation of sn-rallсhangеs i n i n d i v i d u a l o r g a n i s m s .I n a g r o u г r d Ь r е a k i n gе s s ; r yp u Ь l i s Ь е d i n 1 9 7 5 Ь e сhallеngеd thе rrеo-Dаrwit-tiаnviеw that nzrtuгal sеlесtion ассounts for

86с)

870

Stаnlеу all еvolutionary pattеrns and сonсludеd that this геduсtionist сonflation of gеnеtiсs with еvolution is misguidеd. Slow, gradual сhar-rgеdoеs not aссount for thе majority of important еvсllutionaryсhangеs oЬsеrvaЬlе in thе fossil rесord, whiсh appеar to Ье muсh mсlrе suddеn and aЬrupt than was е х p е с t е du n d е r n a t u r a l s е l е с t i o n .Н е r е a s o n е dt h a t j u s t a s i n d i v i d u a l su n d е r natural sеlесtion arе favсlrеdfor Ьoth thе aЬility to survivе to rеproduсtivе maturity аrrd thе aЬility to produсе many offspring, spесiеs arе favorеd for lеngthy еxistеnсе (whiсh allows grеatеr сhanсе for spесiation) and thе tеn. dеnсy to produсe пrany daughtеr spесiеs. In this analogy spесiation is thе analoguе to birth, and еxtinсtion to dеath. A striking сonsеquеnсе of this viеw is that thе сoursе of еvolution hаs Ьееn influеnсеd morе Ьy random faсtors than sсiеntists had formеrly Ьеliеvеd. Sinсе Stanlеy's modеl proposеd that most еvolutionary сhangе takеs plасе at thе spесiеs lеvеl, and sinсе spесiatiсln (oссurring nrost oftеn Ьy gеographiс isolation) is dirесtеd Ьy fairly arЬitrary еnvironmеntal faсtors, pattеrns in thе history of lifе aге сomparaЬlе with a statistiсal random walk, in whiсh long-tеrm trеnds аrе largеly aЬsеnt. Thе notion of progrеss as an еvolutionary mеtaphor (whiсh hаs had grеat сurrеnсy sinсе Ьеforе Darwin's day) is largеly aЬsеnt from this viеw. Stanlеy'swork is notаЬlе in addition for its еxpliсit attеmpt to promotе сOopеration Ьеtwееnpalеontologistsand Ьiologists.Нis 1968 doсtoral thеsisat Yalе ехaminеd funсtional morphtllogy in ехtаrrtlinеagеsof Ьivalvеs' rеflесting his hopе to Ьring Ьiologiсаl mеthods and data to Ьеar on palеontоlogy. SuЬsеquеntlyin his сarееr hе rеvеrsеdthis impulsе and Ьеgan to agitаtе for grеatеrаwarеnеssof palеontologiсalfindings in thе work of Ьiologists.Along with Gould, Еldrеdgе, Dаvid М. Rаup, Thomas J. M. Sсhopf, аnd othеrs,hе Was rеsponsiЬlе fсlr thе palеontologiсal rеnaissanсеin thе 1970s аnd l980s that saw thе еstaЬlishmеntof palеoЬiology as a thriving disсiplinе.Hе is also thе author of two foundational tехtЬсroks:with Raup hе сoauthored Principlеs of Pаlеoпtologу 0971|, whiсh Ьесamе thе authoritativе tеxt for undеrgraduatе palеontolсlgyсoufsеs (and was not suЬstantially rеvisеd for morе thаn 30 yеаrs), and in 1979 Ьe puЬlishеd thе trеatisе Масroeuolutkm: Раttеrn апd Proсess, whiсh has Ьееn dеsсriЬеd as onе of thе most signifiсant Ьooks in palеontology sinсе G. G. Simpson's сlаssiс Tеm|lсl апd Мodе iп Еuolutioп. B|вLIoGRAPl{Y Raup, D. М., ilnd S. M. Stanlеy.1971.Prinсiplеsof Pаlеoпtolrlgy. Sаn Frаnсisсo: W. Н. }.rееmаn and Сo. Stanlеy,s. M' 1975. A thеoryof еvolutionaЬovеthе sресiеs|еуe|,Prrlcеediпgsof thе NаtioпаlAсаdеmуof SсiепсеsUSA 72, no.2: 646_65О. \979. Маспlеuolиtioп: Pаttеrпапd Prсlсеss. Sаn Franсisсo:.sИ. H. Frееman аnd Сo. .W. 1992. Ехploriпg Еаrth апсlLifе throughТlzис.Nеrv York: H. Frееman and Сo. |996. Сbildreп of thе lсе Аgе: Hotu а Glсlbаl СаtаstrophеАlloшеd Humапs -D.Se. trl Еuoluе. Nеw York: Наrm
StеbЬins,GеorgеL

Gеоrgе Lеdyard StеЬ twеntiеth-сеnturyеvol t l f t h е с е n t u r yа n d i n с r i с s ,i r n с lе v o I u r i o n .H е t h е s еt Ь r е еа r е e s i n h i s thаn any othеr' this Ьс еnсе of plant еvolution е v o l u t i с l n i s t sB. е с а u s еr еvolution and Ьесausе s k y . s I 9 З 7 С е п с t i с sа п a s t h е b o t а n i с а le r с h i n o t o n l y D o Ь z h a n s k yl lеy. Мuсlr of his origin a г y p r o с е s si n p l a n t s p work with Bеrkеlеy gе polyploidy сomplеХ' a d i p l o i d s s u r r o u n d е dЬ y thе synthеtiс rеviеw ar likе polyploidy. Gеorgе l-еdyard StеЬ l 9 0 6 , a n d w e s t h еt h i r and а Nеw York soсia HarЬor, Mainе, whеrе t h е е f f o r r so f h i s p c r е n w h o m w е г е s с i е n t i s t аs еst in natural Ьistory ar vard Univеrsity, a rеn S t a t е si n t h е l 9 2 0 ч .A l r atiсs (floristiсsin partiс HеrЬarium, StеЬЬinsп w i г h Е . С . J е f f г е y 'a w е who had Ьееnhirеd аs timе of his graduation tеrminе phylogеnеtiсrr f l r l w е rf e m i l y ) .H i s f i г s to сontinuе his rеsеarс пiа,|n 19З5 hе aCCept U n i v е r s i t yо f С а l i f o r n .s7оrld an ships in old Сrеpis a promising org ary proсеss and had un еrs to study it (Smoсov

StеЬЬins еаrly distin a n d i n 1 9 3 9 Ь е с a m еа

Stеbbiпs 871 at this rеduсtionist сonflation of ш, gradual сharrge doеs not aсionary сhangеs obsеrvаЬlе in thе lrе suddеn and аЬrupt than was r е dt h a t j u s t a s i n d i v i d u а l s u n d е r LЬilitytо survivе to rеproduсtivе lffspring' spесiеsarе favorеd for tnсе for spесiation) and thе tеn[n this analogy spесiation is thе . A striking сonsеquеnсе of this эеn influеnсеd morе Ьy random zеd. Sinсе Stanlеy's modеl pros plaсе at thе spесiеs lеvеl, and 4еographiсisolation) is dirесtеd )attеrnsin thе history of lifе arе ., in whiсh long-tеrm trеnds arе r еvolutionary mеtаphor (whiсh in's day) is lаrgеly aЬsеnt from s ехpliсit attеmpt to promotе сogists.Нis 1968 doсtoral thеsis at tant linеagеsof Ьivalvеs, rеflесtd data to Ьеаr on palеontology. mpulsе and Ьеgаn to agitatе for ; in thе work of Ьiologists.Along nas J. M. Sсhopf, and othеrs' hе L i s s a n с ien t h е 1 9 7 0 s a n d 1 9 8 0 s s a thriving disсipline. Hе is also .zithRaup hе сoauthored Priпсiгhе authoritativе tеxt for undеrt suЬstantiallyrеvisеd for morе tе trеatisе Масrсleuсllцtitп: Pаtl as onе of thе mсlst signifiсant l's сlassiс Теmprl апd Мodе iп

сlfPаlеoпtologу.San Frаnсtsсо: thеspесiеs|еуe1. Рroсееdiпgsof thе : 646_65О. .W. ss.SanFranсisсo: Н. Frееman Гlис. Nеw Yогk:W. H. Fгееmаn hаl СаtаstrophеАlbшеd Humапs -D.Se.

stеЬbins,Gеorgе Lеdyard (1906_2000) Gеorgе Lеdyard StеЬЬins is rеgardеd as onе of thе major figurеs in twеntiеth-сеnturyеvolutionary Ьiologу. Нis sсiеntifiс сarееr spannеd most of thе сеntury and inсludеd thrее primary arеas of rеsеarсh: Ьotany, gеnе. tiсs' and еvolution. Hе is еspесiаllywеl1known for his mastеrful synthеsisof thеsе thrее arеas in his 1950 Ьook Vаriаtioп апd Еuolиtioп iп Plапts. Nlore than аny othеr, this Ьook formеd thе ссlnсеptual ЬaсkЬonе of thе nеw sсiеnсе of plant еvolutionary Ьiology and guidеd an еntirе gеnеration of plant еvolutionists.Bесausе this Ьook also rесonсilеd plant еvolution with animal еvolutiоn and Ьесausе it сomplеmеntеd Ьooks likе Thеodosius DoЬzhansky's 19З7 Geпеtiсs апd the Оrigiп of S1lесiеs,StеЬЬinsis gеnеrally rеgardеd as thе Ьotaniсal arсhitесt of thе еvolutionary synthеsis, ranking alongsidе not only DoЬzhansky Ьut also Еrnst Мayr, G. G. Simpson, and Julian Huxlеy. Мuсh of his original rеsеarсh dеlvеd into thе gеnеtiсs of thе еvolutionary proсеss in plant spесiеs likе thе weed Сrеpis. Hе is Ьеst known for his work with Bеrkеlеy gеnеtiсist Е. B. BaЬсoсk, whiсh lеd to thе idеa of thе polypl
872

Stеbbiпs latе 1930s StеbЬins Ьесamе inсrеаsingly intеrеstеd in сеntral proЬlеms of сonсеrn to еvolutionists. Hе mеt and intеraсtеd with Thеodosius DoЬzhansky' who was a frеquеnt visitor to thе Bay arеa, and hе was an aсtivе partiсipant in thе Biosystеmatists Сirсlе, a group of systеmatists who Wеrе supporting thе adoption of tools from сytology, gеnеtiсs,аnd есology to solvе proЬlеms in systеmatiсs.StеЬЬins Ьеgan tсl pursuе plant еvolution full-timе a|ter \9З9 whеn hе Ьеgan to tеaсh Bеrkеlеy'sсoursе in еvolution, taught out of thе agri. сulturе sсhool. His own rеsеarсh turnеd to solving proЬlеms in plant еvolu. tion, and so StеЬЬinsfollowеd сlosеly thе wсlrk of thе Сarnеgiе Institutionоf .Washington at Stanford Univеrsity's tеаm of Jеns Сlausеn, David Kесk, and William Hiеsеy, as wеll as thе work of Еdgar Andеrson and Сarl Еpling' all Ьotanists сonсеrnеd with undеrstandingеvolutionary proсеssеs.Unlikе most of thеsесontеmporariеs,howеvеr, StеЬЬinswas еqually vеrsеd in animal еvolution and followеd thе work in spесiеs likе Drosopbilа psеudoobsсиrа Ьу DoЬzhаnsky and his сollaЬorators. His grand synthеsisof plant еvolution Ьеgan as part of an invitation to givе thе Jеsup Lесturеs at СolumЬia Univеrsity in 1947 (DoЬzhansky had Ьееn instrumеntal in thе invitation). Rеworking his lесturеsfor his еvoiution сoursе' StеЬbins сomplеtеd a Ьook-lеngth mаnusсript thаt wаs puЬlishеd in 1950 as Vаriаtion апd Еuolutioп in Plаnts. Thе Ьook Was an instant suссеss' Was widеly rеad Ьy еvolutionists'and Ьесamе thе authoritativе sourсе for undеrstanding еvolution in thе plant world. In addition to organizing thе nеw fiеld that Ьесamе known as plant еvolutionary Ьiology and sеrving as a kind of tехtbook to youngеr workеrs, thе Ьook also mаdе StеЬЬins thе singlе Ьеstrесognizеdauthority on plant еvolution at that timе. StеbЬins сontinuеd his еvоlutionary rеsеarсhеsinto thе 1950s whеn hе took a nеw position as сhair of thе Gеnеtiсs Dеpartmеnt at thе Univеrsity of California in Davis, Сalifornia. Hе сontinuеd to writе а sеriеs of important synthеtiс Ьooks on plant еvolution, inсluding Сhrсlmсlsomаl Еuolution iп Higher Plаnts tn 1971 and Flotuеriпg Plапts: Еuolutioп аbouе tbe Speсies Leuel in 7974. TЬe lattеr sеt forth a sеriеsof сontrovеrsial thесlriеsсonсеrning thе origin of thе angiospеrms and was сonsidеrеd сritiсal rеading for graduatе studеnts and yorrngеrsсholars. Не also еditеd an important сo1lес. tion еxploring phеnomеna likе adaptivе rаdiation and island Ьiogеography with HеrЬеrt Bakеr in 196.5 tjt,IеdThe Gеnetiсs of Сoloпiziпg Spссles. StеЬЬins also wrotе gеnеral Ьooks on еvolution |tke The Bаsis of Progrеssiue Еuolutioп in 1969 and authorеd a widеly usеd univеrsity tеxtbook that wеnt through thrее еditions titlеd Procеssеs of Оrgаniс Еuolutioп in thе latе 1'960s.In1977 hе сoauthоrеd yеt anothеr сomprеhеnsivеtеxtЬook on еvolution with Thеodosius DoЬzhansky, Franсisсo Ayаlа, and Jamеs Valеntinе,titlеd simply Еuolutioп' His tеaсhing еffсlrts Wеrе not limitеd only to gradllatе and undеrgraduatеinstruсtion Ьut also еxtеndеd to dеvеloping an Amеriсan high-sсhool сurriсulum riсh in thе Ьiologiсal sсiеnсеsthat arguеd that еvolution was thе сеntral unifying prinсiplе. Hе was an еspесially aсtivе mеmЬеr of thе Biologiсal Sсiеnсеs and Сurriсulum Study's еfforts to rеform highsсhool Ьiology еduсation in thе Unitеd Statеs and aсtivеly fought against

еfforts Ьy so-сallеd sсit

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In thе 1960s StеЬЬin еspесially to prеsеrvе (

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mеntal pattеrns so as t(

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Was still aсtivе in writin1 dеath in 2000. BIBLIOGRAPHY

Сrawftlrd, D. J., and V. B. G, Lсd1,аrJStс|'|'iпs Liесhtеnstсin:A. R. G D o Ь z h a n s k у ,T . 1 9 З 7 . G е l Univеrsity Prсss. DoЬzhansky, Т.' F. |. Ayal S a n F r а n с i s с r э!:V . H . Smoсоvitis,V. B. ] 988. Bс G. Lеdyard StеЬЬins' |997. G.l,еd'vard Аmеriсап JoLtrпаIof I Smoссlvitis,V. B.' аnd F. I tsiсlgrаphiсаl Меmrпrl S o l Ь г i g ,o . 1 9 7 9 . ( i е o r g еl and P. Ravеr.r,еds., Тr Сolumbia UnivеrsitуJ S t е h h i n s ,C ' I . I 9 5 0 . V J , . Univсrsity Prеss. |966. Prrrеssеsоi 1969. Thе I]аsis.' Cartllinа Prеss. 197|. Сhromosоп Wеslеу. 1971. Рlou,еriпgI МA: l}еlkr.rаpPrсss of StеЬЬins' G. l-., аnd Н. G. Nеw York: Aсadеn.rlс

Supеrorganism

A supеrorganism is аn parts that arе Or сan p Thе idеa of thе supеror a n d , a s a p p l i е dt o h u m а

Supеrorgапism rеstеd in сеntral proЬlеms of with Thеodosius DoЬzhansky, h е w а s a n a с г i v еp а r t i с i p а n ti n tists Who wеrе supporting thе l есology to solvе proЬlеms in эvolution full-timе after |939 clution, taught out of thе agrilving proЬlеms in plant еvolu: of thе Сarnеgiе Institution of еns Сlausеn, David Kесk, and Andеrson and Сarl Еpling, all :ionaryproсеssеs.Unlikе most s еqually vеrsеd in animal еvoDrosophilа pseudoobscurа Ьу a s p a r t o f а n i n v i t a t i o nt o g i v е )47 (DoЬzЬansky had Ьееn in:turеsfor his еvolution сoursе' that was puЬlishеd in 1950 as ' Was an instant suссеss' Was 'uthoritаtivе sourсе for undеron to organizing the nеw fiеld logy and sеrving as a kind of nadе StеЬЬins thе singlе Ьesttimе. :hеs into thе 1950s whеn hе еpartmеnt at thе LInivеrsity of to Writе а sеriеs of important ; Сhromosomаl Ещiutioп in Еuolцtion аbouе tbe Spесies ontrovеrsialthеoriеs сonсеrnonsidеrеd сritiсal rеаding for so еditеd an important сollесtion and island Ьiogеography :s of Сoloniziпg Speсiеs. SteЬТhe Bаsis of Prсlgrеssiue Еuornivеrsity tехtЬook that wеnt rgаniс Еuolutioп in thе latе prеhеnsivеtехtЬook on еvolu\yala,and Jamеs Valеntinе, tiе not limitеd only to graduatе : d t o d е v е l o p i n ga n A m е r i с a n :iеnсеsthat arguеd that еvolus an еspесiallyaсtivе mеmЬеr udy's еfforts to rеform high; аnd асtivеlyfoughг аgаinst

еfforts Ьy so-сallеd sсiеntifiс сrеationists to undеrminе thе sсiеntifiс lеgiti. maсy of еvo1utionaryЬiology. In thе 1960s StеЬЬins inсrеasingly Ьесamе eсtivе in сonsеrvation еfforts, еspесially to prеsеrvе Сalifornia's nativе flora. Hе Ьесamе a popular figurе and tеaсhеr and аЬlе spokеspеrsonfor еvolution. By thе latе 1970s StеЬЬins hаd еmеrgеdas onе of thе пrorе visiЬlе еvolutionary Ьiоlogists. Hе сontinuеd pursuing his rеsеirrсhеsinto еvolution, but in thе 1960s hе Ьесamе morе hеаvily involvеd in nеwеr studiеs to solvе importаnt quеstions ..gеnеto сharaсtеr,,'or undеrin Ьiology dеaling with thе transformation of standing nrorе prесisеly thе mесhаnisms Ьy whiсh gеnеs affесtеd dеvеlopmеntal pаttеrns so as to lеad to thе oгigin оf novеl Ьut adaptivе traits and сharaсtеrs.Hе rеtirеd from thе Univеrsit1,of Сalifornia at Davis in 197З Ьut Was still асtivе in writins artiсlеs and Ьoсlks on еvolution until thе timе of his d е a t hi n 2 0 0 0 . BIBLIOGRAPHY еds.2О04.ThеSсiепtifiсPауlеrsof Сrawford'D' J., and V. B. Smосоvitis, Rсgnuп-rVеgеtaЬiIе, уo|. 142..RLrggеll, G. Lеdуаrd Stеbbiпs,.|r,(1L)29_2000l. A. R. G. GantnеrVеrlаg. Liесhtеnstеin: DoЬzhаnsky,T. |9З7. Gепеtiсsапd thе Оrigiп оf Spесiсs.Nеw York: СolumЬia UnivеrsityPrсss. аnd J. \W.Vаlеntinе'1977,Еuolutioп. DоЬzhаnsky,T.' F'.I. Ayala,G. L. StеЬЬins, San Frar.rсisсo: W. H. F-rеепrаn. Thе lifе and work of Snroссlvitis, V. B. 1988.Botаnyаnd thе еvolutionar1,synthеsis: PhD dissеrtation, СornеllUnivеrsit1'. G. l-еdyardStеЬЬins' Jr. UrrpuЬlishеd 1997,G, LеdyardStеЬЬins synthеsis(1924_1950). Jr. аnd thе еvtllutionary Аmеriсаtt.|ourпаlof Btltапу84: 1625_1637. . . L е d y a r dS t е Ь Ь i n(s1 9 0 6 - 2 0 0 0 ) . S m o с o v i t i sV,. B . ,a n d I . . . .А| .y a l a . 2 0 0 4G Biogrа1lhiса!Меmrlirstlf thе Nаtiопаl Асаdеmу of Sсiепсеs85 З_24. In o. SolЬrig,S. Jain' G. B. Johnson, SolЬrig,o,1979. GеorgеLеdyilrdStеЬЬins. and P. Ravеn,еds.,Тoplсsiп Plапt PopиIаtioпl3iolсlgу,1--l7. Nеw Yоrk: СolumЬiаUnivсrsityPrеss. G. L. 19.50.Уаriаtiollапd Еuolutirlпiп Plапts.Nеw Yоrk: СolurтЬiа StеЬЬins, UnivеrsityPrеss. 1.966.Prrlсеsses of ОrgапiсЕt,rllutklп.ЕnglеwoodСliffs,NJ: Prеntiсе-Нall. Еulllиtioи.СhapеlНi[l: Univеrsityof North 1969.Тhе Bаsistf Рпlgrеssiuе Сilrсllinа Prеss. 1971'.СhroпtсlsспlаIЕuolutioп iп HigЬсr P/azrs. Rеading, МA: Addison. .!7еslеу. 1974. Flotuеriпg Plаnts: Еutllиtiсlп аbouе thе Spесiеs Lсuеl. СamЬrtdgе, MA: Bеlknap Prеss сlf Нarvard Unir.еrsit},Prеss. .l StеЬЬins,G. L., аnd Н' G. t]аkеr,еds. 965.7.hе Gепеtiсs of СoloпiziпgSpcсiеs. Nеw Yоrk: Aсirdспriс Prсss.

-иB.s.

Supеrorganism A supеrorganism is аn еntity that funсtions as an orgаnism Ьut is madе of parts that arе or сan propеrly Ье сonsidеrеd organisms in thеir оwn right. Thе idеа of thе supеrorgаnismlong antеdatеsthе Ьirth of еvсllutionaryidеas and, as appliеd to humаn soсial systеms,саn indееd Ье found in thе thinking

87З

874

Superorgапism of thе Grееk philosophеrs. In his Re1lиbliс Plato likеnеd thе idеal statе to thе individual soul, arguing that еaсh has thrее parts: thе thinking part' in thе statе rеprеsеntеd Ьy thе rulеrs or guardians; thе spiritеd part, in thе statе rеprеsеntеdЬy thе auхiliariеs (soldiеrsand сivil sеrvаnts);and thе аppеtitivе part' in thе statе rеprеsеntеdЬy thе artisans and shopkееpеrs.This kind of аnalogy lеnt itsеlf wеll to diffеrеnt philosophiеs' and in thе ninеtееnthсеntury, with thе сoming of еvolution, thеrе wаs muсh еnthusiasm for sееing thе statе as аn еvolving еntity, akin to an organism. In partiсular, thе Еnglish еvolutionist HеrЬеrt Spеnсеr arguеd strongly thаt wе sее in thе stаtе mеthods of organization idеntiсal to mеthods of organization in thе individual, notably thе way in whiсh Ьoth еntitiеs funсtiоn Ьеst whеn thеy ехhiЬit a strong division of laЬor, with a part of thе Ьody doing that and only that for whiсh it is Ьеst suitеd. Today pеrhaps thе soсiaI organiс analogy is Ьеst sееn in thе thеorizing of thosе who Ьеliеvе that units of сulturе аrе akin to gеnеs.Riсhard Dawkins proposеd suсh a thеory inТhе Sеlfish Gепe (\976|, arguing that сulturе is dividеd into mеmеs analоgous to gеnеs' аnd hе and thе philosophеr Daniеl Dеnnеtt arguе that sсlсiеtyсan Ье analyzеd as a kind of mеmеtiс gеnotypе with strong similaritiеs to thе individual Ьiologiсal gеnotypе. Thе supеrorganismсonсеpt was hintеd at (if not Ьy that or any namе) by Сharlеs Dаrwin tn Оп thе Оrigiп of Speсiеs. Hе was strongly сommittеd to thе viеw that natural sеlесtion works for and only for thе individuаl. Hе сould not sее that adaptation сould еvеr Ье for thе Ьеnеfitof thе group at thе еxpеnsе of thе individual orgаnism. Antiсipating thinkеrs today, Darwin madе it сlеar in сorrеspondеnсеwith natural sеlесtion'sсodisсovеrеr,Alfгеd .W.allaсе, Russеl that еssеntially hе thought that if sеlесtion works for thе group' it is always opеn to сhеating Ьy thе individual. A сhеatеrЬеnеfitsfrom its own еfforts, as wеll as thosе of thе group, whеrеаs a nonсhеatеrlosеs Ьесausе of thе сhеatеr. Howеvеr, individual sеlесtionfailеd tсl еxplain thе rolе of stеrilе workеrs in thе soсial insесts, spесifiсally thе hyrnеnoptеra (ants, Ьееs, and wаsps). Thе proЬlеm is that it sееmsthat individuаls in thеsеspесiеsgivе all to thе grorrp at thе еxpеnsе of thеir оwn laЬors. Darwin finаlly dесidеd that thе intеgratеdgroups formеd Ьy thе hymеnoptеra,paradigmatiсallythе honеybее hivе, сan Ье rеgardеd as organisпrsin thеir own right. Thus sеlесtion сan work on thе wholе, with stеrilе workеrs Ьеing rеgardеd as part of this largеr unit, just аs individual Ьody parts arе intеgratеdinto a funсtioning wholе organism. In thе 1960s and 1970s, with thе сoming of soсioЬiology, a disсiplinе that appliеs Ьiology to thе study of soсial Ьеhavior, and thanks partiсLllarlyto powеrful modеls that showеd how apparеntly altruistiс Ьеhavior сan Ье еxplainеd in tеrms of advantagе to thе individual (sеlfish-gеnеthеory), Darwin's kind of thinking was dismissеdby Ьiologists.Thе idеa of tЬе supеrorganism was rеgardеd as Ьеyond the rеalm of thе hеlpful' a sеntimеntrеinforсеd Ьy thе idеa's unfortunаtе politiсal сonnotation5-5цсh organiс thinking was a favoritе of thе National Soсialists-and Ьy its assoсiation with woolly mеtaphysiсs.Тhе Gaia hypothеsis of .}arnеsLovеloсk, in whiсh thе еarth is

сonsidеrеd an orgаnism its parts' was takеn as way of undеrstandingtl as a funсtion of a gеnеr саn work for thе Ьеnеfi wholе-thе supеrorgan laг, thе lеading studеnt thаt in trying to undеrs unwisе and unhеlpful t< thеir own right. It is mr parts of thе wholе, wr гathеr than on thе indiv to idеology or mеtaphy orеtiсal and ехpеrimеn of thе most сhallеnging to show. в|вLIoGRAPнY

Dawkins,R. 1976.Тhе Sе HбlldoЬlеr,B., and Е' o. \ R u s е ,M . 1 9 8 0 .С h a r l е sD r 6 15-630.

Sуstemа Nа,turаe (|

Thе Swеdish Ьotanist is iustly сrеditеd with t nomеnсlаturе that has thе 13 еditions of his S; assoсiatеd with an еss spесiеs. In 17З5 Linnaеus wa сinе. Ii7ith thе еnсourag lishеd thе first еdition of ..oЬsеrvations''and of t title, Sуstemа Nаturсlе : Сlаssеs, Оrdiпes' G eпеr systеm: thrее kingdoms into сlassеs,ordеrs, gеn blеs hе сlassifiеshumans сrthеr primates (Simiа), Аsiаtiсus' Africапus, an ln thе fiгst oЬsеrvari turе,'' Linnaеus arguеs1 сlosеly rеsеmЬlеsits pa multiply and inсrеasеo

SystеmaNaturaе ltо |ikеnеdthе idеal statе to thе parts: thе thinking part, in thе ; thе spiritеd part. in tlrе statе v i l s е г v a п t s )a; r l d t h е a p p е t i t i v е and shopkееpеrs'This kind of liеs, and in thе ninеtееnth сеnr s m u с h с n t h u s i а s mf o r s е е i n g rganism. In partiсular, thе Еnrongly that wе sее in thе statе ; of orgаnization irr thе individunсtion Ьеst whеn thеy еxhiЬit body doing thаt аrrd only that э soсial organiс analogy is bеst hat units of сulturе аrе akin to э r у t n T h e S е l f i s hc е п e ( \ 9 7 6 ) , ; analоgous to gеnеs' and hе at soсiеty сan Ье analyzеd as а ritiеs to thе individual Ьiologiif not Ьy thаt or irny nаrnе) Ьy Hе lvils strсlnglyсommittеd to rd only for thе individual. Hе r thе Ьеnеfitof thе group аt thе lating thinkеrs today, Dаrwin sеlесtioп'sсodisсovеrеr,Alfrеd :hat if sеlесtion works for thе ividual. A сhеatеr Ьеnеfitsfrom whеrеas a nonсhеаtеr losеs Ье:сtion fаilеd to ехplаin thе rolе lly thе lr,vпlеlloptегa(ants, Ьееs, i n d i v i d u а l isn t h е s еs p е с i е sg i v е laЬors. Darwin finally dесidеd еnoptеra'paradigmatiсally thе in thеir own right. Thus sеlесkеrs Ьеing rеgardеd as part оf г е i n t е g r a t е di n t o a Г u n с t i < t n i n g .soсiobiology, a d i s с i p l i n еt h a t or, and thаnks pаrtiсularly to tly altruistiс Ьеhavior саn Ье lual (sеlfish-gеnе thеory)' Darsts.Thе idеa of thе supеrorgаnhеlpful,a sеntimеnt rеinforсеd ls-suсh orgаniсrhinking was y its assoсiation with woolly ovеloсk, in whiсh thе еаrth is

сonsidеrеd an organism and its dеnizеns (irlсluding humans) arе соnsidеrеd its parts, was takеn i1s an ехеmplаг of аr-rattraсtivе Ьut ultimаtеlv stеrilе way of undеrstanding thе proЬlеms of thе еrrvironпlеnt.Rесеntly, howеvеr' as a funсti
SуstеrпаNаturаe (Carl Linnaеus) Thе Swеdish Ьotanist Сarl Linnaеus (аlsс-lknown as Сarl von [-inn6) is justly сrеditеd with thе hiеrarсhiсal systеnl of Ьiologiсal taхonomу and sinсе its dеvеlopn1еt]tir1 nomеnсlaturе thаt hzrs dominatеd tах<;n
87.'

876

Systсmatiсsаnd thс Oгigin of Spесiсs сan sее that еvеrrtuallythеrе must Ье somе singlе original pair oг individual fоr еaсh spесiеsсrеatеd Ьy God. ln suЬsеquеntoЬsеrvatiсlnsLinnaеus сlaims that God's plаn is tо Ье disсovеrеd in thе oЬsеrvation of naturе' and that it is thе duty of mаn to unсovеr this hiddеn p|an so thаt hе might Ьеttеradmirе God's work. Hе also arguеs that Ьy studying nаturе' Wе сan prсlvidеa Ьеttеr foundation for Ьuilding, сommеrсе' food supply, and mеdiсinе to Ьеttеraсhiеvе a h е а l г h i е rs t a t е . Тhе following еditions of the Sуstеmа Nаturае grеw from thе modеst first еdition to thе 3,000-pagе 13th еdition of \770. This growth was largеly duе to thе addition of nеw tахa to thе taхonomiс taЬlеs, Ьut thеrе Wеrе lmpoгtant сhangеs as wеll. In thе 1Othеdition of l 758 Linnaеus introduсеd his systеm of Ьinomial nomеnсlaturе, whеrе еaсh spесiеs is idеntifiеd Ьy thе now-familiar gеnus-spесiеsnamе. But most signifiсantly, Linnаеus also ге. visеd his сonсеption of spесiеs.In thе 1740s Linnaеus was сonfrontеd with еvidеnсе that natural hyЬridization had oссurrеd among plants, produсing diffеrenсеs of kind. By 1755, hе сonсludеd that hyЬridization сould form nеw spесiеsof plants (von [,inn6and DaldЬеrg 1755). Сonsеquеntly hе aЬandonеd his сomпritmеnt to thе fiхity of spесiеs,сlЬsеrvingthat pеrhaps Gоd had сrеatеd an individual oг mating pair for еасh gеnus аnd that nеw spесiеs wеrе produсеd Ьy intеrgеnеriссrossеs.Signifiсantly'hе lеft opеn thе quеstion whеthеr thеrе arе limits to this proсеss. Linnaеus latеr took this idеa еvеn furthеr, spесulating in thе 1Зth еdition of thе Sуstеmа I'Jаttlrаеthat thе original individuals оr mating pairs might rеprеsеntordеrs' rathеr than gеnеra' аnd that еvеn nеW gеnеra сould Ье сrеatеd through hyЬridization. BlBLIoGRAPнY Fringsmyr,T., еd. 1983.I-iппаеus, thе Мап апtl His V(/сlrk. Bеrkеlеy:Univеrsitу of СаliforniaPrеss. Lаrson'J. t-. 1968.Thе sресiеsсonсеpt
Sуstemаtics and the origin of Speсies (Еrnst Мayr) Еrnst Мayr plаyеd a сеntral rtllе in сonstruсting and promсrtingthе synthеtiс thеory of еvсllution,dеvеlсlpеdin thе 1930s and 1940s. Latеr hе was its сhiеf advoсatе. Sуstеmаtiсs апd thе Оrigiп of Speсies wаs his first major сontriЬution to that thеory. Its kеy fеaturе is а dеfеnsеof thе thеory of spесiatiсlnЬy g е с l g г a p h i сi s o l a t i o n . TЬe pсllуtуpiс spесiеsis this Ьсlok'sсorе idеa. Thеsе arе spесiеsthat show distinсt variеtiеs or suЬspесiеs. Mаyr сonсеntratеd his rеsеаrсh on gеographiс variеtiеs. In pаrt hе did this Ьесausе hе was fasсinatеd Ьy thе proсеssеsthat сausе populations to Vary from onе plaсе to thе nехt. Also, as a musеum сurator rеsponsiЬlс for r-ramingand сataloging spесimеns, Мayr strugglеd daily with dесisions aЬtlut how muсh vаriation hе should attriЬutе

to variеtiеs,suЬspесiеs thеsеunits? M,y. *.., n taxonomists strugglеdv attеmрt to dеsсгiЬеthе 1 lrе thought should Ье d w а s г r l о t е di n h i s t r . l i n l 9 2 0 s t s е r l i n .l n l 1s е n ь A m е r i с а n а u d i е n с с .I n . rеl, Ьеtwееn Mayr i.rnd Although Мayr hаd rеs now an Arnеriсаn-геsi to Goldsсhmidt's Ьеliеf jumps, сausеd Ьy maс Ьook, The Маtеriаl Bа. thаt еvolutiсlnary сhan show this (sееthе figurе volumе). М a y г с r l n s i d е r е гJ h с tllаrlеd to nсWspесiе to Ьесomс gеographiс population ttl :rссumu tion. If it rепrаinеd irl m а t с r i a lw o u I ds t i I lf l o distinсtivеnеss.onсе a tirln would аdаptit ttl d t l с еd i s г i n с t i v е n е sAs l.t n t l n e с l а p г i v (еh i l n g е 5\ f o u n d с r с f [ е с t .1 T h с s r shifting-Ьalanсеthеory R е g а r d l с s so f h o w . l i s t rеsultеd in rеprсlduсti f l o w r ' Г g с n е t i сm а г с r parеnt spесiеs Was rее oссurrесl. |n Sуstеrпаtiсs Маyr spесiеsrаnk. This Ьесa hе did not invеnt this с wаs a major dеfеnsеo с ( ) n с е pm t аdссvоIuгio n а tи r а l r l n е - f o г с | а s s tions of this tеst.It wаs r с | a t i rе | 1 ' m . r I l r l u r т l . с Ьесeusеit ol.fеrсJ.r сrit sonаl Ьiаsеs of taxono sеnsеthat his rrpproaсh еntifiс r'vtlrk.

S\.stеmatiсs and thе Origin сlf Spесiеs 877 linglе original pair oг individuаl nt oЬsеrvаtionsLinnaеus сlaims )sеrvationof rraturе,and that it n so thаt hе might Ьеttеr admirе naturе' Wе сan pr
]is lй/ork. Bеrkеlеy:l-Jnivеrsity rs.Isis.59.no. З:297_299. thе FirstЕditiс>п. М. J. S. ЕngеIhеrIаrrds: ts.dе Graаf. tio botапiса mеtаmсlrp h rlsеs jla.

-R.А.R.

es (Еrnst Мayr) ng and promoting thе synthеtiс l d 1 9 4 0 s .L a t е r h е w а s i t s с h i е f с,sWas his first nrаjoг сontriЬr-rэ of thе thеory of spесiation Ьy : e . Т h е s еa г е s p е с i е st h а r s h o w :ntrаrеd l-ris rеsеaгсlr ()п Еlеohе wаs fasсinatесlЬy thе pro. rе plaсе to thе nеХt. Also, as a :l сataloging spесil-nеns, Мayr h variation hе should irttriЬutе

tсl variеtiеs,suЬspесiеs,and spесiеs.\й/lrеrеshould hе draw thе linеs Ьеtwееn thеsеurrits?Мa1'r was nсalсirсtrmstаnсеs.Thosе adаptations сould pro. dLrсеdistinсtir,еt.tеss. Altегnativсly'onсе .1popr-rlation was physiсally sеparatеd, norradaptivе сhangеs сould aссr-rmulatсfrom еithеr gеnеtiс drift or thе for.lndеrеffссt' (Thеsе othеr sсеnarios wеrе dеrivеd from Sеwall Wright's s Ь i f t i n g - Ь a l a n с еt h е o r y r l f е v t > l u t i o nw , Ь i с l r M a y r a d v o с a t е di n h i s Ь o o k . ) Rеgаrdlеss of l-rсlwdistinсtir,еfеaturеs irrosе,Mayr 'rгguеd,thеy somеtimеs rеsultеd in rеpгoduсtivеly isolating thе lсlсal population. If that oссurrеd, flow of gеnеtiс matеriel wаs n() longеr possiЬlе еvеn if сontaсt with thе parеnt spесiеs lvlrs rееstаlllishеd.If that f1ow stoppеd, truе spесiation had oссurrеd. In SуstemаtiсsMayr dеfеrrdеdrеprodttсtivеisolation as а simplе tеst for spесiеsrank. This Ьесamеthе сorе tlf thе Biologiсal SpесiеsСonсеpt. Though hе diс]not invеnt this сtlnсеpt' Мayг wаs its prinсipal aсlvoсаtе'Sуstemаtiсs rvas a majсlr dеtЪrrsеof rhis idеa. NIа1'гаrguеd tlrirt tlrе Ьiologiсal spесiеs сol-tсеptrnadе еvсllutiсlnarysеnsе,and it pгoduсеd a rеal unit-hе сallеd it a паturаl onе-fсlr сlassifiсаtion.At thе sanlе timе Mayr rесognizеdthе limitatiorls of this tеst. It was diffiсtrlttсt study irl thе fiеld. It madе sеnsеonly for a rеlirtivеl1.srnirll nuпrllеr сlf orgаnisms. Rеgaгdlеss,Маyг insi.stеdon this tеst Ьесаusеit offегеda сritеriorrindеpеndеnt
878 Systеmatiсsand thе Origin of Spесiеs In addition to Promoting сеrtain thеoriеs and praсtiсеs, Sуstеmаtiсsalso had an agеnda about partiсipation in еvolutionary studiеs.This agеnda rvas douЬlе sidеd. on thе onе hand, Мayr promotеd his ow,l-lprofеssion-musеum systеmatiсs and Ьiogеography-witl,rin еvolutionаry studiеs. Не сomplainеd that too muсh еmphasis had Ьееn plaсеd on aЬstraсt proЬlеms in gеnеtiсs. Bесausе еvolution oссurrеd in есologiсal spaсе and timе, hе еxplainеd, its study rеquirеd thе knowlеdgе of wholе organisms plus thе Ьiogеоgraphiс skills of systеmatistsand zсlologists'NotaЬly, Mayr tiеd his Ьook сlosеl,vto Thеodosius DoЬzhansky,s ()еnetiсsаnd thе origiп of Spесies(19з7) as еqual partnеrs in that сonvеrsation. On the othеr hand, Мayr nееdеd his fellow ..musеum mеn'' to сonsidеr еvolutionary studiеs and othеr Ьiologiсal proЬlеms as Worthy topiсs {or study. In Sуstеmаtiсs Мayг lropеd to providе rnсldеls that illustratеd how that study сould Ье donе. Dеspitе its suссеss,}иIayrpuЬlishеd only orrе еditiorr сlf Sуstemаtiсs.His 1963 book Апimаl Speсiеsаnd Еuolиtioи w:rs its sеquеl' BIBLIOGRAPHY ^Г. DoЬzhansky, I9з7, Gепеtiсsаnd thе origiп of Spесles. Nеw York: СolumЬia UnivегsityPrеss. Goldsсhmidt,R. 1940. Тbе Маtеriаl Basisof Еuсlhrfloz.Nеrv Hаvеrt,СT: Yаlе UnivеrsityPrеss. Мayr, Е. l940. Spесiationphеnomеnain Ьirds.АlnеriсапNаtцrаlist74:249_278. 1942.Sуstеmаtiсsапd thе Оrigiп of Spесies. Nеw York: СоlumЬia UnivеrsityPrеss. on gеnеtiсаlproЬlеrlls: l948. Thе Ьеаringof thе nеw sуstеmatiсs Thе n?ltuге of spесiеs.Aduапсesin Gcпetiсs2: 2О5_2З7. 1963.АпimаIS1lеciеs апd Еuolutiсlп.СamЬridgе,MA: BеlknаpPrеssof -J .С. Hаrvаrd UnivеrsityPrеss.

T

Taphonomy

Тaphonсlmy, litеrally tl (from ihе Greek tаphos p г o с е s s е so f p г е s е г v а reсord. Taphonomists r fossil rесord, and сomp dеrstand thе proсеssеst rесord and to еstimatеt logiсal information сap parts, taplronotniс prсlс sity of spесiеs and mor and last oссurrеnсеsof Sеvеral rеsеarсhthеm l . U s i n g t h е s t а t еt l f 1 meпtаl сoпditioпs. Softin most саSеs lo\^/oхyg lrnd еаr dесt-'mpсlsition. fеatur and tissr-lе-gradе пlеnts са11Ье higlrl1'dur in many sеttings'and th o f d а m a g еi n a l l г е m а i irrg insigl-rtsintо thе lоса thе sеdimеntaryroсk th сhеmiсal indiсators.Th. or not, largе-Ьtldiеdor l of fossilization,and thе thе loсаl еnvironmеnt с lifе еnviror-rmеnt). 2. Quantifying how f s i t i o п o f f o s s i lb i t l г а s I. п ir-rсludеthе followillg: within a singlе tlеd inr taхon bесаusеshort-tе stеad rеduсеs oЬsеrvеd smаll oг fragilе пlorphs suсh as marinе nrollus

and praсtiсеs,Sуstemаtiсs also onary studiеs.This аgеnda was эd his own profеssion-musеum tionary studiеs.Не сomplainеd r а Ь s t r а с tp r o Ь l е m s i n g е n е t i с s . rсе and timе, he ехplainеd, its anisms plus thе Ьiogеographiс , Мayr tiеd his Ьook сlosеly to ,rigiп of Spеciеs(19З7) as еqual hand' Mayr nееdеd his fеllow diеs and othеr Ьiologiсal proЬ;s Мayr hopеd to pгovidе mod)nе. lnе еdition of Sуstеmаtlсs. Нis s its sеquеl.

Spесiеs. Nеw York: СolumЬia и/loz. Nеw Нavеn, СT: Yalе nеricапNаturаlist74: 249-27 8. ls. Nеw York: СolumЬia )n gеnetiсal proЬlеms:Thе naturе Ьridgе,МA: BеlknapPrеssof

-J'С.

т

Taphonоmy Taphonomy, litеrally thе study of gravеs or еmЬеdding of organiс.rеmains (from thе Grеek tаphos),сan Ье сharaсtеrizеdmorе gеnеrally as thе study of proсеssеs of prеsеrvation and how thеy affесt information in thе fossil rесord. Taphonomists usе laЬ and fiеld ехpеrimеnts' pattеrn ana|ysis in thе fossil rесord, and сomputеr simulations and othеr modеling mеthods to undеrstand thе proсеssеsЬеhind thе aссumulation and dеstruсtion of thе fossil rесord and to еstimatеthе rеsсllvingpowеr' сomplеtеnеss,and fidеlity of Ьi
880

Таphonoпtl' (quitе surpгisingly) to havе littlе nеt еffесt. (b) Thе impaсt of low prеsеrvation potеntial tln oЬsеrvеd еvolutionirry durаtion: arе taхa rvith skеlеtonsof low prеsеrvation potеntial morе likеly to Ье singlеtons (known from singlе oссurrеnсеs owing to low frеquеnсy of fossilization), сlr arе thеy instеad morе likеly to havе artifiсially lеngtЬеnеdgеolсlgiсrаllgеs Ьесirusеpoor quality of prеsеrvation lеаds to spесimеnsЬеing assignеdto alrеady-known taхa (lumping)? T'hе formеr proЬaЬlv holds whеn onе сompi1rеssoft-bodiеd rvith Ьiorlinеrаlizеd groups, but thе lattеr is morе likеly am()ng minеralizеd groups. (с) lfhat impасt havе long-tеrm trеnds-suсh аs thе n
ilarly, thе absеnсе oi (r d е p o s i t s .d е s p i t еt h е p r е сountеrparts (rn tеrms l of prеsеrvation),is сorn1

thе Сrеtaсеous-Tеrtiary nosaurs and many rее Еvеn rесords with poor r е с o g n i г i o no f s u с h l а 1 1 inсrеasingly sophistiсat opеd to pеrmit data frol Ье synthеsizеd into rigor timеsсalеs. в|BLIoGRAPHY

A. K., s. М. Bеhrеnsmеyеr, Ir-r D. H' pаlеoЬiologу. 10З_147. Perspeсtit',е, Kidwеll, S. N4.,and s. ]v1.t biolo for еvolutitll-tаr1, 5 61 - 588 . M a r t i n ' k . Е . | 9 9 9 .Т а p h с Prеss. Urrivеrsitr'

Tеilhard dе Сhaгdir

Piеrrе Tеilhard dе Сharс of thе lеаding palеoаnth half of thе twеntiеth сеnt сovеry of Pеking Мan, n undеr half а пlillion уеa now only сasts ехist.)Hе o f t h е P i l t d o r v nf o r g е r i е ogist and populaг sсiеnс most сеrtainly not thе са Dееply movеd Ьy hrs .

as а strеtсhеr Ьеarег,Теi it with еvolutionary idес пomе|lol1сlf Мап (Lе Рht

progrеssingthrough r аri and thе Ьiosphеrе(thеli

оf human сonsсiousnе еvolution's progrеssivеrс Point' whiсh in somе wr Nonе of tlris sounds r fluеnсеd Ьy thе vitalist . man Hеnri Bеrgson,anс

Теilhаrd dе Сhаrdiп b) Thе impaсt of low Рrеsеrvation: arе taхa with skеlеtons of singlеtons(known from singlе silization), or arе thеy instеad logiс rangеsbесаusеpoor qualrssignеdto alrеady-known taхa onе сomparеs soft.Ьodiеd with kеly among minеralizеd groups. а s t h е n o r t h W а r dp I a t е - t е с t o n i с liс, thе еvolutionary intеnsifiсa; a n i s m s ,a n d Ь r o a d f l u с г u a t i o n s ltary rесord prеsеrvеd-had on I rеsеarсh attеntion is сurrеntly paraЬility of youngеr and oldеr ity or timе valuе) of individual ;appinеss)of thе staсks of sеdim a n y g е n е r a t i o nos f o r g a n i s m s orizon, and what proportion of uссеssionsand is thus availaЬlе samplе is rеquirеd to evaluatе lation lеvеl (as opposеd to thе y thе ratе of sеdimеnt aссumuiсh variеs among dеpositionаl nе-rеgardlеss of whеthеr indirеgardlеssof whеthеr samplе thе sеdimеntary rесord oг thе rminеs our aЬility to idеntify )vеrtimе. It also dеterminеsthе nts сan Ье known and thus our t а х а a n d t h е i r r е l а t i v ег i m i n g thе ехtinсtion of taхon B?). A havе Ьееn dеvеlopеd ovеr thе ' n a lа s p е с t sw ' hiсh arе i]аrtiсufis апd treпds in thе history of ' u n i q u еs o u r с еo f i n Г o r m а r i o n :ation and ехtinсtion, сomplеtnalysis of modеrn-day biotas. rrсе of suсh insights has Ьееn сritiсal intеrvals.For еxаmplе, mal) fossils in PrесаmЬrian dеhе СamЬrian-agеdеposits that pitе intеnsе sampling, grеatly y arosе in thе Сambrian. Sim-

ilarly, thе aЬsеnсе of (many) Сrеtaсеous taхa in suЬsеquent Tеrtiary-agе dеposits, dеspitе thе prеsеnсеin thе Tеrtiary of taxa that arе prеsеrvational сoцntеrparts (in tеrms of body sizе, skеlеtal сomposition, or еnvironmеnt o f p r е s е r v a t i o n )i,s с o m p е l l i n gе v i d е n с еo f a g е n u i n еm а s s е x t i n с t i o n a с r o s s thе Сrеtaсеous-Tеrtiary Ьoundary of many animal groups (inсluding thе di. nosaurs and many rееf-Ьuilding and othеr important marinе linеagеs). Еvеn rесords with poor tеmporal aсuity сan сontriЬutе mеaningfully to thе rесognition of suсh largе-sсalе еvolutionary pattеrns' and a widе array of inсrеasingly sophistiсatеd sampling and analytiс mеthods hаvе Ьееn dеvеlopеd to pеrmit data from sсattеrеdand rеlativеly low-rеsolution rесords to Ье synthеsizеdinto rigorous piсturеs of еvolutionaгy dynamiсs ovеr gеologiс timеsсalеs. BIBLIOGRAPHY Bеhrеnsmеyеr, A. K.' S. М. Kidwеll' and R. Gastaldо.2000.Taphonomyand -Гimе: palеoЬiology.In D. Н. Еrwin and S. L. \Wing,еds,,Dееp Pаlеobiolсlgу,s Pеrspесtiuе, 103_147.Lаwгеnсе,KS: Allеn Prеss. K i d w е l l ,S . М . , a n d S ' M . H o l l a n d . 2 0 0 2Q . u a l i t yс l ft h е f o s s i rl е с o r dI: m p l i с a t i o n s for еvolutionaryЬiology.Аппuаl Rеuiеtuсlf Есologу апd Sуstеmаtiсs33 561-588. Мartin, R. Е. 1999. Tаphoпomу:А PrсlсеssАpproасh. СamЬridgе:Сan-rЬridgе -s.М.К. UnivеrsityPrеss.

Tеilharddе Chardin, Piеrrе(1881-1955) Рiеrrе Tеilhard dе Сhardin was a Frеnсh-Ьorn Jеsuit priеst who Ьесamе onе of thе lеading palеoanthropologists(studеntsof human еvolution) in thе first half of thе twеntiеthсеntury. Long Ьasеd in China, hе was involvеd in thе disсovеry of Pеking Man, now rесognizеdas Нomo еrесtusand dаting from just .War II; undеr half a million yеars ago. (Thе aсtual finds wеrе lost in World now only сasts еxist.) Hе was also' as a studеnt, prеsеnt in Еngland whеn somе of thе Piltdown forgеriеswеrе unсovеrеd.StеphеnJay Gould, thе palеontologist and popular sсiеnсеwritеr' aссusеdTеilhard of thе hoaх, Ьut this is almost сеrtainly not thе сasе. .!far Dееply movеd Ьy his еxpеriеnсеs in World I, whеn hе sеrvеd Ьravеly as a strеtсhеr Ьеarеr, Tеilhard sought to rеinvigoratе Сhristiаnity Ьy infusing it with еvolutionary idеas. The result, puЬlishеd in his mastеrwork The Phenomeпotтof Мап (Lе phёпomёпеhцmаiп, 1955), saw lifе as an upward сlimЬ, progrеssing through various stagеs,notaЬly thе gеosphеrе (thе physiсal world) and thе biosphеrе (thе living world) until it rеасhеdthе noosphеrе (thе world of human сonsсiousnеss or idеas). This noosphеrе itsеlf hе rеad as part of еvolution's progrеssivеroutе upwаrd until it rеaсhеd its apothеosis, thе Omеga Point, whiсh in somе way Tеilhard idеntifiеd with Jesus Сhrist. Nоnе of this sounds vеry Darwinian, аnd it is not. Tеilhard was muсh influеnсеd by thе vitаlist work L'ёuolutioп сrёаtricе (19О7) Ьy fеllow Frеnсhman Hеnri Bеrgson, and hе saw this as supporting a vеrsion of orthogеnеsis,

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Tеilhаrd dе Сhаr,]iп Ьеliеf that tlrеrеis a klnd сlf world 1Ъrсepushing oгganismsup аn еvсllutionaг,v thе laddеr of сhangе until thеy rеaсh thе highеst point, namеly, humankind. Tеilhard garnеrеd praisе frсlrrrlеading еv
Sсiеnсе or nonsсiеnс is todаy gеnеrall,vrесo Ь u i I . lа w o r I d p i с t u r еi r ingl1,.еvеn th
BIBLIoGRAPнY

B е г g s . ' t tH. . l 9 0 - . L . t ; l , r D o Ь z h а n s k 1 ' l .l ч ь - . Т / l-ibrary. Gould, s. J. ] 980.Thе Рil Haught, J. F'.2000. Gr.rd Wеstviеw I)rеss. H е f l t е г 'l ) . l 9 9 . ] . l . l l с H t t t М i n n е а p t l l l *М. N : F . H u х l е v 'J . S . I u ; о ' 1 ' . ' , ' . |\4ап,11_2lj. B. Vlа|] M е d t r r ' lr , P . l 9 6 l . R е v i t R с p r i n t е di l l l ' . М е d . Сo., 1967. R u s с , M . | 9 9 6 . | \ А | ) п аl Id С r l n l ' r i t J g е .\ l , , \ :H l 20О5. Тhе l:'шllu Univеrsity Pгеss. Tсilhаrd dе Сhаrdin, P. l 1959' Гhс Phсlt,

Tеmpoапd Мode (GеоrgеGaylordS A p:rlеontoltlgist lvlro urotс

Тсmptl

tllltl Мttd'

rеsеarсh foсшsеdon kе W h i l е h е . w a sw r i t i n g 7 оf rll: саl сlessifiсntion ling Ьig quеstions. r Тwo suсhqrtсsti
Tеmpo and Мodе in Еvolution

лzorldforсе pushing organisms up qhеstpoint, nаmеly, humankind. tionary Ьiologistsduring his lifе;iastiс aЬout Tеilhard's idеas; in n-Ьorn population gеnеtiсist, fеlt thе prеsidеnts of thе British and |uхlеywas always an athеist and rn orthodoх Сhurсh (for dеtails, ogians' notaЬly thе Саtholiс thеsity and thе Luthеran thеоlogian ology in Сhiсago, who find Tеiltionary palеontologistGеorgе G. : аdmirеd him аs a sсiеntist and alvinist сhildhood сamе through h attitudе to thе vows of povеrty, lly stuсk in Simpson'sсraw. ..I do еdiеnсеto Ье virtuеs, Ьut anyonе saсrеdvows to oЬsеrvе thеm and thrее vows throughout his lifе must Ье сonsidеrеda hypoсritе'' ;on Papеrs,Amеriсan PhilosophR u s е1 9 9 6 ) . Г е i l h а r dh а s h a d s t r o n 8 с r i r i с s . 'iсiousof his thinking. It wаs Ьеriеd thе historiсal authеntiсity of sin. It was also thought thаt hе ln of Jеsus Ьy making thе world han as having сulminatеd in one dеas in his lifеtimе, and еvеn in гmеd its opposition to his thinklriсal friеnds who saw that his h. Tеilhard took too littlе notiсе of lrth. Thеy find unсonvinсing thе еl that hе should havе Ьееn morе еss.But nonе of thеsе сritiсisms s с i е n t i s t sN. o Ь е | P r i z е _ иi n n i n g thе Еnglish vеrsion of the Pbеlirесtеd as muсh toward Julian ,ard Tеilhard. Y/ithout dеnying t should Ье notеd that Tеilhard ]ritiсizеdЬy his own сhurсh, hе s writings should Ье сonsidеrеd and hеnсе Ьy naturе nonhеrеtiсiеntifiс, pеoplе likе Меdawar

Sсiеnсе or nonsсiеnсе, Darwinian

or not' right or Wrong' Tеilhard's vision

is todаy gеnеrally rесtlgrrizеd as thе most important post,-Оrigfu attеmpt to Ьuild a world piсturе inсorptlrating Ьoth Сhristianity and еvolution. Inсrеasingly, еvеn thosе who сan sее thе major proЬlеms arе сoming to rесognizе this. Thе task is not t() rеfutе his vision but to improvе it. BIBLIOGRAPHY H, 1907. L'ёuolutioп сrёаtriсе. Paris: Alсan. Bегgsсlr.r, DoЬzhansky, T. |967 . Thе Biologу of Ultiпlаtе Сoпcеrп. Nеw York: Nеw Amеriсan LiЬrаrу. Gould, s' ]. l980. Thе Piltdоwn сonspiгасy. Nаtиrаl Historу 89 (August):8_28. Hatrght, j. F. 2000. Gtld аftеr Dаrшiп: А Thесllogу of Еuolutkлt. Bouldеr, Сo: Wсstviеw l)rеss. Hеfnеr, P' \99з. TЬе Huпtiп Fасtor: Еuсllutitlп, Сulturе, апd RеIigioп. Мinnеаpolis, МN: Fortrеss Prеss. to P. Tеilhаrd dе Сhardin' Тhе Phепrlmепtlпof Huхlеy, ]. s. 1959. ll.rtroсiuсti
-М.R.

Tеmpo аnd Nlode in Еuolution (GеorgеGaylord Simpsоn) A pаlеorrtologistwho spесializеd in mammals' Gеorgе Gaylord Simpson wroteТеmpo аnd Мodе in ЕuсllutiсlпЬеtwееn 1938 and 1'942.Beforethis his rеsеarсh foсшsеdon kеy momеnts in thе еvolutionary history of mammals. \Х/hilе hе Was Writing Tempo апd Мodе, Simpson also was writing a tесhniсal сlassifiсationof mamtтаls, Ьoth living and ехtinсt. Simpson еnjoyеdtaсkling Ьig quеstions. Two suсh qllеstions Wеrе thе starting point for Tеmpo апd Мodе: (1) what, in faсt, is thе ratе of еvolution in naturе, and (2) What pattеrns rесur in еvo1utionaryhistoriеs?Simpson idеntifiеdthrее еvolutionаry ratеs:ехсеptionalIy slow, normal, and ехсеptionally rapid. In aЬsolutе tеrms' hе said, thеsе ratеs vary from group to group' Ьut as rеlativе ratеs thеy arе distinсtly diffеrеnt phеnoп1еna.Simpson aIso idеntifiеdthrее rесurring pattеrns:spесiation (gradual diffеrеntiаtion of а group into spесiеs)' phylеtiс еvolution (an aссumulating trеnd or dirесtion),and quantum еvolution (a rapid shift in fundamеntal quаlitiеs). Tеmpo апd Мodе ссlrтЬinеd Simpson's dеsсription of thеsе phеnomеnа with a сritiсal study of thеir undеrlying сausеs.For this hе drеw from rесеnt dеvеlopmеntsin gеnеtiсs,mathеmаtiсal populаtion gеnеtiсs'and есology. Hе

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Tеmpo and Мodе in Еvolutiсln was strongly influеnсеd Ьy Sеwall \Х/right'sshifting-Ьalanсе thеorv, whiсh hе lеarnеd from Thеodosius DoЬzhansky. With this thеory аs pаrt оf his largеr understandingof еvo1ution,Simpson put grеat еmphasison natural sеlесtion, taking plaсе in adaptivе landsсapеs,for giving dirесtion to еvolution. Pоpulation sizе also Ьесamе vitally important, еspесiallywhеrr Simpsorrехplainеd quantum еvolution аnd ехсеptionally rapid ratеs of сhangе. Historians frеquеntly suggеst that Sirnpson mеrеly appliеd thеsе thесlry сomptlnеnts. That is wrong. For Simpson thе fossil rесord prсlvidеd thе ultimatе еп-rpiriсaltеst foг a thеoгy. It alsо providеd гaw matеrial for nеw thеorеtiсаl iсlеas,for ехamplе' his own work ol-lratеs and pattеrns.Simpson сгitiсally tеstеdthе thеoriеs hе сonsidеrеd' somеtimеs rеjесtingthеm as unsupportеd Ьy fасts (е.g., gеnеration lеngth oг сhzrngingmutirtion ratеs) and somеtimеs usir-rgthеm to makе novеl pгеdiсtions for studу (е.g.,rеlating small populatiorrsizе to rapid еvolution). ovеrall hе thought of his work as synthеsizingknowlеdgе' not mеrеly сonsuming somеonе еlsе'sidеas. .What was Теmpo апd Мode,s lasting impaсt? TЬе аnswег splits intо its impaсt on thrее audiеnсеs. Теmpo апd Мodе is most rеmеmЬеrеdfor intеgrating palеontology and population gеnеtiсs within thе frаmеrvоrk of thе еvolutionary synrhеsis.[n thе 1930s еvolr'rtionarysttldiеsrvеrеdonrinatеdЬy gеnеtiсs and ехpеrimеntal Ьotаnу-.Rеsеarсhеrsin thеsе afеas saw Simpson's Ьook as an appliсation сlf thеir tесhniquеsthat ехtеndеdthеm into nеw tеrritory аnd gеnеrаlly сonfirnrеd thеir approaсh. Anothеr audiеnсе,pаlеontоlogists, сеlеbrated Tеmpсl аnd Мodе for dеmonstrating to thosе othеr rеsеarсlrеrs that fossils Wеrе thе hеart сlf еvolutiсlnary studiеs and for rеminding thеm that only palеontologistsсould spеak to сегrаin aspесtsof thе suЬjесt.Simp. son himsеlf wantеd to Ьеgin sеvеral сonvеrsations.Hе wantеd palеorrtolo. gists to apprесiatе how muсh morе information сould Ье ехtraсtеd frоm tlrе fossil rесord thаn had prеviously Ьееn thе сasе. Hе also wantеd thеm tо usе nеw statistiсal and Ьiologiсal tесlrrriquеsand to foсus thеiг аttеt-ttionon studying proсеssеs(е.g.'еvolutionary' есologiсal, and tтigratory) as muсh аs on studying fossil oЬjесts.At thе samе timе Simpsorrwаntеd Ьiologiststo apprесiatе modеrn palеоntology as a rigorous, modеrn sсiеnсе. Latеr in his lifе Simpson frеquеntly distanсеd lrimsеlf frorл Tempсl апd Мode, rеfеrring сollеaguеs to his Маjor Fеаtиrеs of Еuolutioп (1953). Hе сonsidеrеd Ьis 1944 Ьook rushеd аnd a Ьit to
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Timofееff-Rеssovs Vladimirоviсh (19(

Nikolаi Vladimiroviсh dеvеlopеd impоrtаnt idс nеtiсs, and thе еffесtsof nеssеd firsthand importa t h е г i s еe n d f а l I o f N а z i Tinlofее{f was Ьorn t in Kaluga provinсе, nеe sidеd with thе anаrсht 1917 aod thеn ioinеd tl paigns, inсluding thе Сr Bеfoге thе rеvolution aсtivеly partiсiрarеd in turnеd. Iл1922 hе Ьеga f l u е n с е dh i s Ь a s i сt h i n k i thе iпrportanсе of gеnе niquеs for unсovеringtl Hе also lеarnеd to thinl and to сonсеntrаtеhis . сroеvolLltion. WЬilе hе wаs studyi thе prеstigiоusInstitutе Timofееff oЬtainеd rigс a n d m o r p h o l o g , vТ. h е l r imеntal and thеorеtiсa phеnogеnеtiсs (l'',hatno fесts of gеnе mutations lеagtlеsat thе lnstitutеl fiеld, inсluding S. S. Сh N. P. DuЬinin. In thisg dеspitе thе faсt that hе s Thе timing of his arr H . J . М u l l е r а r r i v е df r r gan.s сhromosolnе thеo This had bесomе thе or сomЬinаtion Tirnofееff with оpportunitiеsto bе utatlon as an ехpеrt еx duсеd diffеrеnt еffесtsul thе thеorеtiсian'snotior |л 1926 Tinrofееffw; oratoгy of gеnеtiсs.At сirсlе of Russian Ьiolog . pегsonally fгom oskar

Timсlfееff-Rеssousfty 88J rifting-Ьalanсеthеory, whiсh hе this thеory as part of his largеr t еmphasison natural sеlесtion, Lgdirесtion to еvolution. Popu:сially whеn Simpson еxplainеd :atеsof сhangе. Нistorians frеthеsеthеory сomponеnts. That idеd thе ultimatе еmpiriсal tеst ,r nеW thеOrеtiсalidеas' for ех. impson сritiсally tеstеdthе thе1 as unsupportеd Ьy faсts (е.g., ) and somеtimеs using thеm to g small population sizе to гapid rs synthеsizingknowlеdgе' not асt? Тhе answеr splits into its з is most rеmеmЬerеd for intеs within thе framеwоrk of thе rary studiеswеrе dominatеd Ьy гs in thеsе arеas saw Simpson's t е х t е n d е dt h е m i n t o n е w t е r r i Anothеr audiеnсе' palеontolorating to thosе othеr rеsеerсhеrs udiеs and for rеminding thеm in aspесtsof thе subjесt. Simpltions. Hе wantеd palеontoloэn сould Ье еxtrасtеd from thе е. Hе also wantеd thеm to usе d to foсus thеiг attеntion on сal, and migratory) as muсh as npson wantеd biologists to aprodеrn sсiеnсе. rсеd himsеlf from Tеmpo апd :ures of Еuolutioп (1953). Hе o speсulativеand said that his лrsin morе сonsidеrеd fashion.

fiologistапd Еuolutiсlпlsr.Nеw ;z. Nеw York: СolumЬiа оrk: ColumЬiaUnivеrsityPrеss. lology.Nеw York: MсGraw-Нill.

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Timofееff-Rеssovsky,Nikolai Vladimiroviсh (1900_198 1 ) Nikolai Vlаdimiroviсh Timofееff-Rеssovsky Was a Russian Ьiologist who dеvеlopеdimportant idеas in thе study of gеnеtiсmutations' еvolutiсlnarygеnеtiсs' and thе еffесtsof radiation Ьoth оn pеoplе and on есosystеms.Не witnеssеdfirsthand important politiсal rеgimеs, inсluding thе Russian Rеvolution, thе risе and fall of Nazi Gеrmany, and Stalin's politiсal purgеs. Timofееff was Ьorn to a family of minor noЬility Ьut poor сirсumstanсеs in Kaluga provinсе, nеar Mosсow. An admirеr of Pеtеr Kropotkin, hе first sidеd with thе anarсhists' Grееn Army during thе Russian Rеvolution in 19|7 and thеn joinеd thе Rеd Army in 1919.He sеrvеd in numеrous сampaigns, inсluding thе Сrimеan and Polish fronts. Bеforе thе rеvolution Timofееff studiеd Ьiology at МosсOw Univеrsity and aсtivеly partiсipatеd in thе сitу's intеllесtual сirсlеs. Aftеr thе war hе rеturnеd. In |922 hе Ьеgan studying undеr SеrgеiСhеtvеrikov, who hеavily influеnсеdhis Ьasiс thinking aЬout Ьiolсlgy.F.romhis mеntoг Timofееff lеаrnеd thе importanсе of gеnеtiс variation within populations and mastеrеd tесhniquеs for unсovеring thе variation that might bе hiddеn in rесеssivеgеnеs. Hе also lеarnеd to think aЬout еvolution as a population-lеvеl phеnomеnon and to сonсеntratеhis attеntion on small сhangеs in gene frеquеnсy, or miсroеvolution. \Whilе hе was studying undеr Сhеtvеrikov, Timofееff also Ьеgаn work in thе pгеstigiousInstitutеof Ехpеrimеntal Biology' run Ьy N. K. Kol'tsov. Hеrе Т i m o f е е f f o Ь t а i n е d r i g o r o u s t r а i n i r r gi n с o m p a r a r i v еа n а t o m y . s y s t е m a t i с s ' and morphology. Thе institutе wаs Ьесoming a world-сlass сеntеr for ехpеrimеntal and thеoгеtiсal gеnеtiсs. Timofееff dеvеlopеd spесial inгеrеsts in phеnogеnеtiсs(what now is dеsсriЬеdas gеnе ехprеssion),thе сausеs and еffесts оf gеnе mutations, and thе сhеmiсal struсturе of gеnеs.Among his сollеaguеsat thе InstitutеWеrе somе of thе Soviеt Union's lеading figurеs in thе fiеld, inсluding S. S. Сhеtvеrikov, A. S. SеrеЬrovsky,S. М. Gеrshеnson,and N. P. DuЬinin. In this grtlup Timofееff stood out as onе of thе most talеntеd dеspitе thе faсt that hе still hеld no formal univеrsity dеgrее. Thе timing of his arrival at thе institutе was fоrtuitous. In thе samе yеar H. J. Mullеr arrivеd from Сalifornia, сarrying nеws of Thomas Hunt Мor. gan's сhromosomе thеory of hеrеdity аnd stoсks of thе fruit flу, Drosophilа. This had bесomе thе organism of сhoiсе for .й/еstеrngеnеtiсs. In a mastеrful сomЬination Timofееff Ьrought thе two traditions of his training togеthеr with opportunitiеs to Ье found in Мullеr's fly stoсks. Hе quiсkly еarnеd a rеputation as an ехpеrt ехpеrimеntеr.Fоr instanсе,hе isolatеd gеnеs that pro. duсеd diffеrеnt еffесts undеr diffеrеnt dеvеlopmеntal сontеХts. This сonfirmеd thе thеorеtiсian'snotion of plеiotrophy. In 1926 Timofееff was surprisеd Ьy an offеr from Bеrlin to organizе a laЬoratory of gеnеtiсs.At that timе hе was rеlativеly unknown outsidе a smаll сirсlе of Russian Ьiсllogistsаnd still had no univеrsity dеgrее.Thе offеr сamе pеrsonally from oskar Vogt, dirесttlr of tl-rеlnstitutе of Brain Rеsеarсh. Vogt

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Tiтnofeеff-RessoиsДy hаd Ьееn imprеssеd Ьy Timсlfееff's skill as an ехpеriп-tеntеr.!7hеn Timofееff arrivеd, it was to nеw faсilitiеs and thе titlе of hеad of his dеpartmеnt. Timofееff rеmainеd in Gеrnr:rrryuntil 1945. Thеsе Wеrе thе most produсtivе and сrе:rtivеyеars of his с:rrееr.In thе study of gеnе funсtion, fоr instаnсе, hе dеvеlopеd nеw wa,vsttl study gеnе еХpгеssionand rеgulation. Hе ir-rvеstigirtеdthе rеlation Ьеtwееll gеnе struсturе and 1unсtion.Hе dеvеlopеd an irrf]rrеntialthеory to ехplain Ьow Х.rays сausе mutations. This Ьесаmе known as thе hit thеory, dеvеlоpеd with Karl Zimmer and Мax DеlЬriiсk. Thе thеory сomparеd X-rays with ЬomЬs striking targеts аnd ехploding; diffеrеnt targеts produсеd diffеrеnt еffесts.Thеir approaсh inspirеd Еrwin Sсhrбdingеr's fаmous Ьook Whаt Is Lifе? (|944). Timofееff Ьаsеd his thinking on his own dеmorrstrationsof thе linеar rеl:rtiorrЬеtwееnrаdiаtiоn сlosеarrdthе numbеr of mutаtlons prodr'rсеd. In population gеnеtiсsTimofееff extеndеd Сlrеtvеrikov'swork on gеnеtiс virriaЬility'paying spесialаttеntionto thе rеsеrvеsof гесеssivevariation found in wild pоpulations. Studying сhangеsto gеnе frеquеnсiеsgavе him quantitat i v е m е а s u r е so f m i с r o е v o l u t i о n . Thе politiсal situation in Gеrmany and thе Soviеt Urrion prеsеntеdTimofееff with Ьoth oppoгtunitiеs anс1risks. Gеnеtiсs гесеivеdсоrrsidеraЬlеsupport in (iеrnrirrrvaftеr thе Nаtionаl Soсiаlists сamе to powеr in 1933. But Timofееff wаs oldеrеd tO rеturn to the Soviеt Union sеvегаl times in thе 19.]0s' Еaсh timе hе rеfusеd. Friеnds privatеly warnеd him that аrrеst Was likеly iп tlrе inсrеasingly paranoid world of Stalin's purgеs. Furthеrmorе' !иеstеrngеnеtiсs Was Ьеing dеnounсеd aggrеssivеlyЬy Тrofim Lysеnko and his follow. еrs. Bесаusе Timofееff wаs univеrsally idеntifiеd as onе of Russian's lеading advoсatеsof that approaсh, hе knеw that hе faсеd ссlnsidеraЬlеdangеr if hе геturnеd.Friеnds in thе Unitесl Stаtеsеnсouragеdhim to еmigratе from Gеrmany ilnd sесurеd for him thе dirесtorship of a rеsеarсhсеntеr in thе Unitеd Statеs.To tl-rеirsurprisе Tim
as wеll as somе prisоnеrs timе Tin-rofееffсontriЬu disсrrssionо s n how to iс of raсе hygiеnе pгogram tivеly саmpaign for nеgа Т i m o f е е f f r е m a i n е di n viеt army сapturеd Bеrli allowеd somе of his rеsе thе possibility оf moving arеa of radiation Ьiology thе Soviеt military was е ablе еxpеrtisе. I n S е p t е m Ь е r1 9 4 5 , h ' poliсе, who wеrе followr f o г f а i l i n g t o r е t u r nd u r i r tеm. During his impriso muсh of his vision. Aftеr i t a г y s p o n s o r st o w o r k i n a n d h o s p i t a I i z а t i o nT, i m nеar Svеrdlovsk, in thе [ for radiation Ьiology. T| iсinе and gеnеtiсs.It als сеnology. This lattеrrеsе o r а с с u m u l a t еi r l Ь i o l o g and wholе есosystеms.l unitеd with his wifе and ofееff's stаtus sinсе his i undеr rrrilitirry sесrесy,1 .Wеstеrn pathеtiс to thеo Тhе sесrеtwork сontil and rеstriсtionson his li main in thе Urals. Makl Ь i o p h y s i с sl a Ь o r a t o r yi n to trаin Ьiologistsin gеn thе fiеld hе playеd an im1 tеrm сonsеquеnсеsof tht Io 1964 Timofееff wаt hе organizеd anothеr la[ Lеss protесtеd now by h attaсkеd Ьy Lysеnkoists i m е n t i n g o n S о v i е tp r i s t Soviеt Aсadеmy of Sсrе prеssurе from his suppo foг thе Institutе of Mеdi Не rеnrainеd at thе inst proЬlеms, until his dеath

Тimofееff-Rеssouskу 887 n ехpеrimеntеr. !Иhеn Timofееff of hеad of his dеpartmеnt. |5. Thеsе wеrе thе most produсd y o f g е n е f u n с t i o n ,f o r i n s t a n с е , ssion and rеgulation. Hе invеsti.d funсtion. Hе dеvеlopеd an inmutations.This Ьесаmе known tеr and Max DеlЬriiсk. Тhе thetargеts and еxploding; diffегеnt 'aсh inspirеd Еrwin Sсhrбdingеr's ff Ьasеdhis thinking on his own -rradiation dоsе and thе numЬer l C h е r v е r i k o v . sw o r k o n g е n е t i с :rvеsof rесеssivеvariation found е f r е q u е n с i еgs a v е h i m q u а n t i t а Soviеt Union prеsеntеd Timofе:s rесеivеdсonsidеraЬlеsupport 1е to powеr in ]933. But TimoLion sеverаl timеs in thе 1930s. Lеdhim that arrеst was likеly in rrgеs. Furthеrmorе' \wеstеrn gеIrofim Lysеnko and his followfiеd аs onе of Russian's lеading faсеd сonsidеraЬlеdangеr if hе agеd him to еmigratе from Gеr.a rеsеarсh сеntеr in thе Unitеd сiting rumors of poor finanсial ; an inсеntivе to rеmain in Gеras thе dirесtor of a rеorganizеd ophysiсs of thе Kaisеr Wilhеlm )41, Timofееff simply сould not nuеd during \Х/orld \War II. Hе rе Auеr Soсiеty, а сhеmiсal firm l rеfinеmеntfor Gеrmаn аromiс on thе еffесts of ехposurе and is was not wеapons-rеlatеd rеLnatomiс powеr industry. гiеsduring thе war is muсh dе. rеfusеdGеrman сitizеnship' rе. ;h hе was no Сommunist). Нis э, Ьut hе was arrеstеd and diеd 14.Ttmofeeff usеd his politiсal :сtJеwish and Russian rеfugееs,

as wеll as somе prisonеrs and forеignеrs drаftеd into forсеd labor. At thе samе timе Timofееff сontriЬutеd to numеrous programs in Nazi sсiеnсе, suсh as disсussionson how to idеntify сarriеrs of rесеssivеgеnеtiс disordеrs as part of raсе hygiеnеprograms. Although hе wаs ехpеrt in this aгеa, hе did not aсt i v е l y с а m p a i g n f o г n е g a t i v ее u g е n i с s . Timofееff rеmainеd in Bеrlin through 1945. Hе was prеsеnt whеn thе Soviеt army сapturеd Bеrlin. Не сoopеratеd in the oссupation. Soviеt offiсials allowеd somе of his rеsеarсh to сontinuе, and Timofееff sеriously disсussеd thе possiЬility of moving his laЬoratory Ьaсk to Russia. His ехpеriеnсеin thе arеa of radiation Ьiology and gеnеtiсswas сruсial in this nеgotiation.Bесausе thе Soviеt military was еxpanding its atomiс programs' Timofееff had valuablе еxpеrtisе. In SеptеmЬеr 1945, howеvеr, Timofееff was arrеstеd Ьy thе Soviеt sесrеt poliсе, who wеrе following a diffеrеnt agеnda. Hе was sеntеnсеdto 10 yеаrs for fаiling to rеtlrrn during thе war' and hе Was sеnt into thе gulag prison systеm. During his imprisonmеnt Timofееff nеarly diеd of starvation and lost muсh of his vision. Aftеr morе than a yеar in prison hе was rеtriеvеd Ьy military sponsors to Work in atomiс rеsеaгсh.By thе spring of 1947, aftеr rеlеasе and hospitalization' Timofееff Was sеnt to a сlosеd military rеsеarсhсеntеr nеar Svеrdlovsk, in thе Ural Mountains, and askеd to organizе a laЬoratory for radiation Ьiology. This inсludеd studying thе еffесtsof radiation in mеdiсinе and gеnеtiсs.It alsо inсludеd есosystеmsесology, or radiation Ьiogеo. сеnology.This lattеr rеsеarсhstudiеd how radioaсtivе isotopеsmovе through or aссumulatе in Ьiologiсal systеms,for ехamplе, in organisms, food сhains, and wholе есosystеms.This assignmеntсarriеd somе privilеgеs.Hе Was fеunitеd with his wifе and surviving son. Thеy hаd known nothing about Timofееff's status sinсе his inсarсеration two уеars еarliеr. Bесausе hе workеd undеr military sесrесy' Timofееff Was onе of thе fеw Soviеt gеnеtiсists sympathеtiс to !Иеstеrn thеoriеs to rеmain frее from Lysеnko's purgеs. Thе sесrеt work сontinuеd until 1955, whеn Timofееff rесеivеd an amnеsty and rеstriсtions on his lifе Wеrе partly liftеd. Howеvеr, hе Was forсеd to rеmain in thе Urals. Мaking thе Ьеst of his situation, Timofееff organizеd a Ьiophysiсs laЬorаtory in Svеrdlovsk and сrеatеd a sеriеs of summеr sсhools to train Ьiologists in gеnеtiсs,есology, аnd radiation Ьiology. As an ехpеrt in thе fiеld hе playеd an important rolе in assеssingthе сontamination and longtеrm сonsеquеnсеsoftЬe 1957 Kyshtym nuсlеar aссident. In 7964 Timofееff was allowеd to movе to oЬninsk, nеаr Мosсow, whеrе hе organizеd anothеr laЬoratory, now for thе Aсadеmy of Mеdiсal Sсiеnсеs. Lеss protесtеd now Ьy his military сonnесtions' Timofееff was inсrеasingly attaсkеd Ьy Lysеnkoists.Thеy aссusеd him of Nazi сollaЬoration and ехpеrimеnting on Soviеt prisonеrs of war. Hе was Ьloсkеd from еlесtion to thе Soviеt Aсadеmy of Sсiеnсеs. In 1969 Timofееff Was forсеd to rеtirе. Hеavy prеssurеfrom his supportеrs led to an appointmеnt as a sсiеntifiссonsultant for thе Institutеof Mеdiсo-Biologiсal ProЬlеms, dirесtеd Ьy o. V. Gasеnko. Hе rеmainеd at thе institutе, studying spaсе mеdiсinе and various gеnеtiсs proЬlеms. until lris dеаth in 1981.

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Tiпbеrgеn Throrrghсlut his lifе Timofееff dеpеndеd hеavily on his wifе of 50 yеаrs' Hеlеrrа Alехandrovna Fidlеr (1898_197З). An ехсеllеnt ехpеrimеntеr lrеrsеlf' Неlеna сollаЬoratеd in hеr husЬand's rеsеarсh'сoauthorеd many of his еssays' and fully partiсipatеd in thе intеllесtual lifе
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TinЬеrgеn,Niko (1907-1988) Niko TinЬеrgеn was thе third of fivе сhildrеn of a Dutсh sсhooltеaсhеr.As а youth hе Was attrасtеdto thе strong' youth-oriеntеdtrаdition of nirturеstudy that flor"rrishеd in Holland in thе еarly dесаdеs of thе trvеntiеtlrсеrrtury.Не took grеаt pleasrrrеoЬsеrvir-rg animals irr thеir nattlгal haЬitats. In сontrast, hе was not attrасtеd to aсadеmiс zoology, whiсh sееmеdto hirn to dеal too ехсlusivеly with nrr.rsеumor lаЬoratory-Ьasеdехаminations oГ dеad spесimеns. Aftеr ссlnсlr-rdirrg thаt it might Ье possiЬlе to pllrsuе a сarееr.аs an aсаdепriс Ьiologist rvith an oriеntation towагd fiеld studrеs,hе еnrсlllеd as а zoo|ogу studеnt at [-еidеn Urrivеrsity in 1926' Не еarnеd his PhD thеrе in 1932 rд,itha fiеld study of insесt oriеntatitln Ьеhavi
mеnt to his own largеly Ьtlt fеnеwеd tЬеir friеnс сontinuеd to bе lеadеrsс TinЬегgеn'swork wаs еs1 His сontriЬutiorrsinсlud in 1949 to oхford, rvht Ьеhavior stuс1iеs;and p еthology, Tbе Studу rlf l; logiсal studiеs, lтlostnol thе film Siglшls for Suп,i TinЬеrgеn workеd har

iеs grеw in a сoordinatеd stud}'of Ьеhavior'' (е.g. plinе to thrivе it nееdеdt сal сausation' individuаl for his own rL.sеarсh'hе pаrtiсular suссеssto qu( ехpеrimеntаlstudiеsthа of spесifiс Ьеhavior pattt Ьеhaviorаl ес()logy.In rс Ьеhavior, TinЬеrgеn wа Mеdiсinе joinгlу with Kс B|вLloGRAPнY

Burkhardt,R. W., lr. 2005 апd tbc Ltшndiпgof L H. 2003.NiAоЪN. Krr-ruk, О: Апimаl Bеhаuiоur. T i n Ь е r g е nN, . 1 9 5 1 .Т Й eS Nс; ,9.5g'4--,1;a;д. 196.].On аimsаl20:'41О_4ЗЗ.

Trivеrs, RoЬеrt (Ь.

RoЬсrt Тrivеrs is Ьеsг l formеd thе str-rdyof sех a l s o с o n t r i Ь u t е dt o a n u gеnеtiс еlеmеnts and g

lluсtuating asvmmеtry'i Trivеrs wаs еduсаtеd t o r y ( 1 9 6 5 )a n d a Р h D Е. Williams, and hе was ing William Drury, Еrns has suЬsеquеrrtlуhеld f: nia at Santа Cгuz, and F fеssor of antЬropologyl

Тrit,еrs еd hеavily on his wifе of 50 yеars, 3)' An еxсеllеnt ехpеrimеntеr hеr's rеsеarсlr,сoauthofеd rnany of his lесtual lifе of thе sсiеntifiс сommulаnаgеd his soсial litЪ аnd sеrvесlаs

Гimofееff.Rеssovsky. Gепetiсs \ОО.. imofееff-Rеssovskу. S сiепtifi с 3е:()arnЬridgеUnir,еrsityPrсss. and gеogrаphiсalvаriatiоn. In J. i6. oхford: C)xford LInivеrsityPrеss.

-.J.С.

lrеn of a Dutсh sсlrooltеaсl-rеr.As ;.r r-oгiеntеdtradition of naturе studv с а d е so f r h е г w е n г i е t hс е n t u r y . H e thеiг nartrrаlhaЬitаts. In сonrrаst' ' whiсh sееmеdto him to dеal too эasеd ехaminations of deаd spесi' s s i Ь I еt с l p u r s u еc с e r е е rа s а n асalrd fiеld studiеs, lrе еnrollеd as a L 9 2 6 .H e е a г n е d h i s P h D t h е r е i n эn Ьеhavior,modеlеd in Dart after h е а l p h а Ь е t i с а еl n t г 1 .. . K а г l R i t t е r uation hе marriеd and spеnt 14 t h е n r е t u r n е dr o L е i с ] е nU n i v е г s i t r ' :hеDеpartmеnt of Zoology. Thеrе еsеarсhthat inсludеd fiеld as wеll Thе fiеldwork foсusесl on insесts э thе laЬoratory work dеalt for thе сies of fish, thе thrее-spinеdstiсklas his еnсountеr аnd suЬsеquеnt n r a d L о г е r t z( s е еt h е а l p l r e b е r i с a l llumе). Having first mеt Lorenz at ln 19З6, TinЬеrgеn trаvеlеd to of 1937, whеrе lrе workеd with talеnts prсrvеdto Ье сomplеmеnr s l a y i n g r h е с o n с е p r u а li o u n d a in turn apprесiatеd that 'Lorenz lеnts Wеre an invaluаЬlе сomplе-

mеnt to his оwn largеly intuitivе thеorizing.Thеy r,vеrеsеparatеdЬy thе war but rеnеwеd tЬеir friеrrdshipwhеn thеy mеt again in 1948. Although Ьoth сontinllеd to Ье lеadеrs of еrlrologу'sdеvеlopmеntOvеr thе nеxt rlvo dесirdеs' Tinbеrgеn's woгk was еspесially signifiсant for thе disсiplinе's ongoing growth. Нis сorltribLrtitrrrs inсludеd fourrdine in 1948 tlrе journal Bеhаt,irlur;movlng ln 1949 to oхftlrd, rvhеrе hе еstaЬlishеd an inlluеntial program of animal Ьеhavioг studiеs; and puЬlisЬing ln 19.51 thе first systematiс ovеrviеw of егhology,The Studу of Iпstittсt.Hе аlso Wаs a suссеssfulpopularizеr of еthologiсal studiеs, most notaЬly in his Llook Сurirlиs Nаturаlists (19.'s) аnсi in thе filrrr Sigпаlsfor Suruiuаl (Huglr Falkus, dirесtor, |968). TinЬеrgеnworkеd hard in thе 1950s аnd l 960s to sее that еthologiсalstudiеs grеw in a сoordinаtеdfаshion.Oftеrrprоmtlting еthologу as ..thеЬiologiсal study сlf Ьеhavior'' (е.g.,TinЬеrgеn l963, 4l 1), hе insistеdthаt for thе disсiplinе to thrivе it nееdеdto addrеsssinrultanеouslythе quеstionsof physiоlogiсal сar-rsatiorr, individLral dеvеlopmеnt, еvolutionarv history, and ftrnсtiorr.As for his own rеsеarсh,hе found himsеlf in thе 1950s and l 960s turning u,ith ;lirrfiсtrlагstlссеss to quеstions of Ьelrаviorаl funсгion. Thе сomparativе and еxpеrimеntalstudiеsthаt hе and his studеntsсonduсtеd on thе survival vаluе of spесifiс Ьеhavior pattеrns rеprеsеntеda signifiсant сontriЬution to modеrn Ьеhaviоral есology. Ilr гесtlgrritionof his сorrtriЬutions to thе study of anirnal Ьеhavior, TinЬеrgеn lvas awаrdеd tЬe 797З NoЬеl Prjze for Phуsiology or Mеdiсirrе jсlintly with Korrrad Lorenz аrrd Kагl Rirtег von Рrisсh. BIBLIoGRAPнY Burkhаrdt,R. W., Jr. 20О5.Pаttсrпsoi.Bеhаuittr:Kспrаd Lrlratz, Nikrl Tiпbеrgеп, апd thеFouпdiпgof Еthologу.Сhiсаgo:Univеrsitytlf СhiсаgoPrеss. Kruuk' H.2003' Nikr|s Nаturе:А Lifе г{Niho.Гiпbеrgепапd Нis Sсiеltсc of Апimаl Bе|lаuklur,oхford: oхford UnivеrsitvPrеss. -Гhс TinЬеrgеn, N. 1951. Studуtf lпstiпсt.oхfоr.d:oхfсlrd Uпivеrsit1,Prеss' ()trious 1L)58. NLlturаljsts. [-сlndon: СoLlrrtгy Lifе. 1963.On aims аnd mеthсldsof еtholog1'.Zеitsс|lriftfiir.Гiеr1lsусhсllogie 20:410-4З3' -R.vиB.

Trivеrs, RоЬеrt (ь. \943) RoЬеrt Trivеrs is Ьеst knowr-rfor fivе еarly еssays (I977_1976) that transformеd thе stuсly of sех diffеrеnсеs'seх ratios, and soсial Ьеhavior' Hе has also сorrtriЬutеdto a rrumЬеrсlf othеr arеas, inсluding thе еvolution of sеlfish gеnеtiс еlеmеnts and gеnomiс imprirrting, thе сausеs and соnsеquеnсеsof fluсtrrаtirrgas,vllllтlеtr},' аrrd tlrе bеl-rirvioгal есolog1,
hаs suЬsеquеntlyhеid fЪсult,vpсlsitiorrsat Н:rrvard' thе Univеrsity of Сalifornia at Sаnta Сruz, and Rutgеrs Univеrsity, whеrе sinсе 1994 hе has Ьееn prof е s s o ro f a n t Ь r o p o l o g уа n d Ь i o l o g i с а ls с i е n с е .

889

890

Triuеrs Trivеrs's еarly еssays apply gеnе's-еyеrеasoning' as pionееrеd Ьy Gеorgе С. Williams (1,966)and !7illiam D. Нamilton (1964a,1964ь,1967) in thе 1960s, to spесifiс proЬlеms that had not Ьееn addrеssеd so dirесtly or fully. The 1971r еssay on rесiproсal altruism asks how сoopеration сan еvolvе Ьеtwееn unrе. latеd individuаls and idеntifiеs somе еvolutionary сonsеquеnсеsto Ье ехpесtеd (е.g., ongoing sеlесtion for improvеd aЬilitiеs to dеtесt сhеating and for improvеd аbilitiеs to сhеat, possiЬly involving taсtiсs suсh as sеlf-dесеption) (Тrivеrs 1971). The \972 еssаy on sехual sеlесtion idеntifiеs diffеrеnсеs in pаrеntal invеstmеnt in offspring as a kеy paramеtег that ехplains muсh aЬout thе еvolution of sеx diffеrеnсеsin morphology and Ьеhavior, inсluding thе sporadiс oссurrеnсеof sех-rеvеrsеdspесiеs(Тrivеrs \972).The 197З еssayon sехratio adjustmеnt in rеlation to parеntal сondition arguеs that onе sеx (typiсally malеs) may oftеn Ьеnеfit morе than thе othеr from aЬovе-avеragеparеntal in. vеstmеnt' and that pаrеnts arе thеrеforе еxpесtеd to Ьias thе sеxеs of thеiг offspring in rеlation to thеir prеsеnt aЬilitiеs to invеst (Trivеrs and Willaгd 1973). The |974 еssay on parеnt-offspring сonfliсt arguеs (from Hamilton's thеory of inсlusivе fitnеss) that offspring should oftеn attеmpt to еХtraсt morе invеstmеnt than thеir parеnts would prеfеr to givе, аnd thаt wеaning сonfliсt thеrеforе rеprеsеntsa truе divеrgеnсе of intеrеstsrathеr than a mеrе Ьrеakdown of сommuniсation (Тrivеrs 1974).The 1976 еssay on sех alloсation in soсial insесts tеsts this parеnt.offspring сonfliсt modеl in a systеm whеrе unusual сoеffiсiеnts of rеlationship and pattеrns of invеstment gеnеratе prеdiсtions that diffеr gгеatly dеpеnding on whеthеr mothеrs (quееns)or daughtеrs (workеrs) сontrol thе sеx ratio (Trivеrs and Harе 1976). Еaсh of thеsе еssays has stimulatеd hundrеds of rеfinеmеnts,ехtеnsions, and empiriсal tеsts and has affесtеd thinking in a suЬstantial arеа of rеsеarсh. In 1985 Trivеrs puЬlishеd a tеxtЬook, Sociаl Еuolиtioп' whicЬ givеs a сomprеhеnsivе, aссеssiЬlе, and riсhly illustratеd aссount of thе proЬlеms' data, and thеoriеs of Ьеhаvioral есology and soсioЬiology. In 2002Ьe puЬlishеd a Ьook of sеlесtеd еssays' Nаturаl Sеlеction апd Soсiаl Thеorу, whiсh inсludеs informativе and highly еntеrtaining aссounts of thе intеllесtual and pеrsonal Ьaсkgrounds tO еaсh of his fivе еarly еssays and siх suЬsеquеnt works, with Ьriеf postsсripts сommеnting on dеvеlopmеnts sinсе еaсh еssay first appеarеd. Тrivеrs's most rесеnt book (with Austin Burt) is Gепes iп Сoпfliсt: Tbe Biologу of Selfish Gепеtiс Еlemепts (2006), whiсh synthеsizеsthеorеtiсal and еmpiriсal work on thе full гangе of selfish gеnеtiс phеnomеna, inсluding transposaЬlе еlеmеnts' gеnе сonvеrsion and homing' gеnomiс imprinting, and sеvеral variеtiеsof nonrandom sеgrеgation,suсh as gеnomе еxсlusion. в|BLIoGRAPHY Burt, A.' аnd R. Trivеrs.2006. (}епеsiп Сoпfliсt:Tbе Biologуof SеlfishGепеtiс Еlеmепts.СаmЬridgе'МA: Harvard UnivеrsityPrеss. Нamilton,W. D. 1964a.Thе gеnеtiсаlеvolutionоf soсialЬеhaviourI.Jourпаlсlf ThеoretiсаlBiolсlgу7: 1_76. 1964ь. Thе gеnеtiсalеvtllutionof soсial ЬеhаviorrrI|. |ourпаlof Tbеoretiсаl B i с l l o g у7 : 1 7 _ 5 2 . 1967. Ехtraordinaгy 477-488.

Trivеrs, R. 1985. Soсiаl Еu' 2002. Nаturаl Sеlе Triuеrs. Oхfсlrd: С)хfo -l Trivеrs' R. L. 971. Thе еv Biologу 46: 35_57. 1972. Parеntаl irrv Sеlесtioп апd thе Dеsс 1974. Parеnt-offsp Тгivеrs' R. I-., and H. Hаrе insесts.Sсiепсе |91 2: Trivеrs' R. L., and D. Е. !и thе sех гаtio of с'ffspг Williams, G, С' 1966. Аdа1 Univеrsity Pтеss.

Тrit,еrs

oning' as pionееrеd Ьy Gеorgе C. 964a, \964Ь, 1967) in thе 1960s. ssеd so dirесtly or fully. TЬe |971 еration саn еvolvе Ьеtwееn unrеnary сonsеquеnсеsto Ье ехpесtеd эs to dеtесt сhеating and for img taсtiсs suсh as sеlf-dесеption) sеlесtion idеntifiеs diffегеnсеs in .amеtеrthat еxpiains muсh aЬout y and Ьеhаvior,inсluding thе spoеrs |972|.The 197З еssayon sехtion arguеsthat onе sех (typiсally r from aЬovе-avеragеpaгеntal in:сtеdto Ьias thе sеxеs of thеir off_ .!Иil\ard nvеst (Trivегs and |97З). Lrguеs(from Нamilton's thеory of attеmpt to ехtгaсt morе invеst, and that wеaning сonfliсt thеrеrathеr than a mеrе Ьrеаkdown of ;ay on sех alloсation in soсial in' lin a systеmwhеrе unusual сoеfstmеnt gеnеratе prеdiсtions that (quееns)or daughtеrs (workеrs) ). Еaсh of thеsееssayshas stimud еmpiriсal tеsts and has affесtеd .аlЕuolutioп'

whiсh givеs a сomaссount of thе proЬlеms' data, ,Ьiology.In 2002 hе puЬlishеd a d Soсiаl Theorу, whiсh inсludеs ; of thе intеllесtual and pеrsonal and siх suЬsеquеnt woгks, with ts sinсе еaсh еssay first appеarеd. is Genеs iп Сoпfliсt: The Biolrlgу nthеsizеsthеoгеtiсal and еmpiriphеnomеna, inсluding tгallspos_ gеnomiс imprinting, and sеvеral ]еnomеeхсlusion.

Thе Bkllogу of Sеlfish Gепеttс ity Prеss. lf soсialЬеhаviour1.lournаl сlf 'еhаviourII.Jсlurпаl сlf Tbесlretiсаl i6:477-488.

Tгivеrs, R. 1985. Soсiаl Еuolutioи. Mеnlo Park, СA: Bеnjamin/Сummings. 2ОО2. Nаtltrаl Sеlесtirlп апd Soсiаl Thеorу1 '\еlесtеd Pаpеrs сlf Ro|эеrtL. Тriuers. oхford: Oхfoгd Univегsity Prеss. Trivеrs, R. L. 197|. Thе еvоlution of rесiproсal аltruisllr.Qttаrtеrlу,Rat,iatuсlf B i o l с l g у4 6 : 3 5 - 5 7 , 1972. Pаrental invеstmеnrand sехual sеlесtiсln.In B. CamрЬеII, ed.,Sехuаl Selесtiсlпапd the Desсепt of ll7ап, 1З6-179. Сhiсago: Aldinе-Athеrtоn. I97 4. P ar ent.offspring ссlnf]iсt.Аm еr i сап Z o o l ogi st 14 : 249 _264. Тrivеrs' R. l,.' and H. Hаге. 1976.I1ap|odiploidy аnсi thе еvolution llf thе sосial insесts.Sсieпcе 19 |: 25О_2.6З. Trivеrs, R. L.,;rnd D. Е. Willаrd. |973. Nаtur:rl sеIесtitlnof pаrеnrаl аЬiiity to varl' thе sех ratio Of offspring. Sсiс'tlсс179:90_92, \Williams,G. с. 1966. Аdаptаtioп апd Nаtиrаl Sеlеt.tiсltl. Prinсеton, N.|: Рrinсеton

UnivеrsityPrеss.

-/.s.

89I

Vаriаtion аnd Еuolution in Plаnts (GеorgеLеdyard StеЬbins) Vаriаtiсlп апd Еuolиtiсln iп Plапts, puЬlishеd in 1950, is thе mastеrwсlгk of thе gеnеtiсist аnd Ьotanist Gеorgе Lеdyard StеЬЬins. It is thе fourth and final work of a quаrtеt of Ьooks that еstaЬlishеdthе synthеtiс thеory of еvolution, thе Amеriсan vеrsion of thе thеory that еmеrgеd in thе 1930s from thе Ьlеnding of Darwinian sеlесtion and Меndеlian gеnеtiсs. SteЬЬins's Ьook, thе only onе of thе four еxpliсitly rеstriсtеd to onе group of organisms, сamе latеr than thе othеrs-Thеodosius Dobzhansky's Genеtiсs апd the Оrigiп сlf Spесiеs in 1937, Еrnst Mayr's Sуstemаtics апd the Оrigiп of Spесies in 1942, and Gеorgе Gaylord Simpson's Tеmpo аnd Мode iп Еuolutirп in \944. The intеntion had Ьееn that thе Ьсltanist Еdgar Andегson would сontriЬutе to thе projесt' but whеn hе failеd to do so, Dobzhansky ехpliсitly and intеntionally rесruitеd StеЬЬins,gеtting him to givе thе Jеsup Lесturеs at Сolumbia in 1946 and all thе way urging him to сomplеtе and puЬlish thе work. Givеn its gеnеsis,it is not surprising tЬat Vаriаtiсln апd Еuolution iп Plаnts rеflесts partiсularly thе еvolutionary vision of DoЬzhansky, namеly, that .\Х/right's Sеwall shifting-Ьalanсе thеory of еvolution is thе сorrесt сonсеptual foundation for еvolutionаry studiеs' a foundation on whiсh onе must now Ьuild using еmpiriсal data. In StеЬЬins's Ьook not only is thеrе a gеnеrаl foundation frоm \il/right,Ьut thеrе is аlso сarеful disсussiоn of thе dеtails of thе shifting-Ьalanсеthеory. For ехamplе, StеЬЬinsoffегеda dеtailеdand gеnеrally sympathеtiс сovеragе of \Wright'sсеntral сlaim that muсh еvolution is duе not to thе dirесt еffесts of natural sеlесtion Ьut to gеnеtiс drift, whеrе random faсtors of Ьrеedingin small populations arе a kеy proсеss.Нowеvеr' although StеЬЬins thought drift an important notion, Ьasеd on his own oЬsеrvations and pеrhaps influеnсеd Ьy а gеnеral skеptiсism aЬout drift that was growing in thе latе 1'94Оs,hе gavе no unamЬiguous and еnthusiastiсеndoгsеmеnt of thе notion. Hе wгotе a Ьook in thе sсhool of thе synthеtiсthеorists, not a slavish еndоrsеmеntof thе thinking of othеrs. Indеed,dеspitе its plaсе in thе gеnеral piсturе of thе synthеtiсthеоry, StеЬЬins's Ьook (longеr and morе dеtailеd in many rеspесtsthаn thе othеrs) is in somе rеspесtsthе odd man out) for hе is muсh сonсеrnеd to show аnd disсuss aspесtsof thе plant world not gеnеrally геprеsеntеd(or signifiсant)in thе animal world. Thе faсt that many plants arе asеxual, for instanсе, gеts muсh 892

disсussion. So also doе hybridization, whеrе t' сhangе gеnеs.Мajor ссl ploidy) whеrе сhromosс nеw spесiеs(in thе sеns arе formеd in onе gеnеr Thеrе is aIsodisсuss othеr writings StеbЬinsl rists) hе is dееply сoml world' likе thе othеr tl valuе-ladеndisсussions апd Еuolиtiсlп iп Plапts of modеrn еvolutionary sсiеnсе,and in this aim B|вLloGRAPHY

DoЬzhansky,T. 1'9З7.Gе UnivеrsityPrеss. Мayr, Е. |942.Sуstеmаt lJnivеrsityPrеss' Rusе,M. 1996.Мoпаd to СаmЬridgе'MA: Har Simpson'G. G. 1944'Tеl UnivеrsityPrеss. .с S m o с o v i t i sV,. B . 1 9 8 8 B G. l-еdyardStеbbins G. L' |950. Vаr StеЬЬins, UnivеrsityPrеss.

Vestiges of the Nаt (Robеrt СhamЬеrs

Vеstiges of thе Nаturаl plеmеnt, Ехplапсttiсlпs thе Sсottish publishеr R all organisms, living an of еvolutionary сhangе tion sсroungеd from a .

somе not' СhamЬеrs'sп muсh philosophiсal as l iп Оп thе origin сlf S1l o n a f i r m s с i е n t i f i сЬ а s i СhamЬеrs opеnеd Vс hypothеsis,whiсh supp othеr Ьodiеs сondеnsin gin of lifе. Partiсular сrit thе frost-fеrn pattеrns l(

Vеstigеsof thе Natural Histoгy of Сrеation disсussion. So also doеs thе faсt that muсh plant сhangе rеvolvеs around hyЬridization, whеrе two virtually isolatеd groups mееt and start to еxсhangе gеnеs.Мajсlr сovеraЕ]еis givеn to thе pесuliar plant proсеssеs(polyploidy) whеrе сhromosomе sеts arе douЬlеd or сomЬinеd еntirе' and whеrе nеw spесiеs(in thе sеnsеof Ьеing rеproduсtivеly isolatеd from thеir parеnts)

J in 1950, is thе mastеrwoгk of StеЬbins.It is the fourth and fi_ hеd thе synthеtiс thеory of еvo'hat еmеrgеd in thе 1930s from Меndеlian gеnеtiсs. StеЬЬins's striсtеd to onе group of organius DoЬzhаnskу's Gепetiсs апd ; Sуstеmаtics апd the origin of ;on,s Tеmpo апd Мodе iп Еuo't thе Ьotanist Еdgar Andеrson lе failеd to do so, DoЬzhansky ls' gеtting him to givе thе Jеsup ay urging him to сomplеtе and lriаtioп аnd Еuolиtioп iп Plапts of DoЬzhansky' namеly, that llution is thе сorrесt сonсеptual lation on whiсh onе must now ,ok not only is thеrе a gеnеral :еful disсussion of thе dеtails of lЬins offеrеd a dеtailеd and gеn'al сlaim that muсh еvolution is гion Ьut to gеnеtiс drift, whеrе )ns arе a kеy proсеss.Howеvеr' t notion' basеd on his orvn oЬ:ral skеptiсism aЬout drift that amЬiguousаnd еnthusiastiс еnthе sсhool of thе synthеtiс thеng of othеrs. rе of thе synthеtiс thеory, StеЬy rеspесtsthan thе othеrs) is in ' сonсеrnеdto show and disсuss ;еntеd(or signifiсant)in thе an;ехual' foг instаnсе, gеts muсh

a r е f o г m е d i n t l n еg е n е r a t i o n . Thеrе is also disсussion of еvolutionary trеnds in plants. Although in his othеr writings StеЬЬinsmakеs it vеry сlеar that (likе thе othеr synthеtiс thеorists) hе is dееply сommittеd to a progrеssionist viеw of thе еvolutionary world, likе thе othеr thеorists hе is vеry сarеful not to introduсе еxpliсit valuе-ladеn disсussions aЬout highеr and lowеr into Vаriаtioп апd Еuolиtioп аnd Еuolutitlп iп Plапts. This work was intеndеd to сomplеtе thе parаdigm of modеrn еvolutionary Ьiology as a funсtioning and rеspесtaЬlеЬranсh of sсiеnсе,and in this aim it suссееdеdadmiraЬly. BIBLIOGRAPHY DoЬzhansky,T. 1937.Gепеtiсsапd thе origiп tlf Spесies.Nеw York: Сolumbia UnivеrsityPrеss. Мayr, Е. |942. Sуstеmаtiсsапd thе origiп of Speсiеs'Nеw York: СolumЬra UnivеrsityPrеss. Rusе' М. 1996.Мoпаd trl Мап: Thе Ссlпсеptof Progrеssiп ЕuolutioпаrуBiologу. СаmЬridgе,MA: НarvаrdUnivеrsityPrеss. Simpson,G. G. 1944. Теtпpoапd Мсlde iп Еuolutiсlп.Nеw York: СolumЬia Prеss. Ur.rivегsity Thе lifе and work of syr"rthеsis: Smoссlvitis, V. B. 1988.Bоtаnyand thе еvolutionary Univегsity. PhD dissеrtation, Сornеll UnpuЬlishеd G. LеdyardStеЬЬins, Jr. StеЬЬins, G. L. 1950.Vаriаtioпапd Еuolutiсlпiп PIапts.Nеw York: СolumЬia Univеrsity Prеss'

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Vestiges of the Nаturаl Historу of Сrеаtion (RoЬеrt СhamЬеrs) Vеstiges rf thе Nаturаl Historу of Сrеаtioп, first puЬlishеd in 1844 (a sup. plеmеnt' Ехplапаtioпs, appеarеd in 1845)' was authorеd anonymously Ьy thе Sсottish puЬlishеr RoЬеrt СhamЬеrs. In this work СhаmЬеrs arguеd that аll organisms, living and dеad' arе thе еnd rеsults of a long' natuгal proсеss of еvolutionary сhangе. Although hе madе muсh usе of еmpiriсal informa. tiоn sсroungеd from a variеty of sourсеs, somе sсiеntifiсally rеspесtaЬlе and s o m е n o t ' С h a m Ь е r s ' sm а i n i n t е n tW a s t o p r o v i d еа n o v е r a l lw o г l d p i с t u r е .а s muсh philosophiсal as anything еlsе. Hеrе hе diffеrеd from Сharlеs Darwin tn oп thе origin of Speсies, whеrе thе intеnt was to put еvolutionary studiеs o n а f i г m s с i е n t i f i сЬ а s i s . СhamЬеrs opеnеd Vеstigеs Ьy rеfеrring favоraЬly to thе so.сallеd nеbular hypothеsis,whiсh supposеsthat thе univеrsе itself еvolvеd, with planеts and othеr Ьodiеs сondеnsingout of gasеs.Nехt hе taсklеd thе quеstion of thе origin of lifе. Partiсular сritiсal sсorn Was rеsеrvеdfor СhamЬеrs's suggеstionthat thе frost-fеrn pattеrns lеft on windowpanеs in сold wеathеr wеrе indiсativе of

89З

894

Vеstigеsоf thе Natural History оf Сrеаtion a link bеtwееn thе living аnс1thе matеrial worlds. СhamЬеrs movеd nеxt to a grеatеr arеa of strеngth, rlrе fossil rесord. |n his Priпсiplеs of Gaсlogу (1830_1833), Сharlеs Lyеll hаd introduсеd Jеаn-Baptistс Lirmarсk's thеoгy

of еvolution, сomplеtеly misltnсlеrst:rndingit as an аnswеr t() thе trpwardrising fossil rесord. As it hаppеns, Lamarсk sаiсl псlthing on this suЬjесt.but thanks to Lyеll this is how it was intеrprеtеd,and СlrаrnЬеrsWas nothing if not thorough in his dеtailеd disсussion of thе progгеssionfrсiеry,somеtЬiпg to wlriсh hе was сtlrnп-rittеd Ьoth as a vеry suссеssful Ьtlsinеssmanand as thе аrrthor of many shortеr piесеs for his own puЬliсаtions-piесеs that hymnеd thе virtuеs of еffort and thrift and pointеd thе way tсl futurе suссеss.It was hardly any surprisе thаt thosе who sharеd his philсlsophy tеndеd to likе his book, and thosе who put rеal сhangе in thе hands of Gоd, Providеnсе,lсlathеd Vеstigеswith a passion. Adаm Sеdgwiсk, profеssсlгoI gеology аt thе Univеrsitr' of СamЬridgе and somеtimе tеaсhеrof Chаrlеs D:rrrvin,spесulatеdthat Veslцсs must havе Ьееn writtеn Ьy а woman and thеrrdесidеd thet nо mеmЬеr:of tlrе fаir sеx сould havе pеnnеd suсh filtlr: .'thе аsсеnt up thе hill of sсiеllсеis ruggеd and thсlrnv, and ill suitеd for thе drapеry of thе pеttiсoat'' (Sеdgrviсk1845' 4). Sсottislr sсiеntist David Brеwstеr, Ьiographеr of Nеwton, dесlаrеd that it showеd thе gеnеral dеgеnеraсy into whiсh Britain had sunk. ..It would :rugur ill fоr thе rising gеnеration,if thе mothеrs of Еngland wеrе infесtеdwith thе еrrors of Phгеnology: it would auguг worse WеГеthеy tаintеd witlr Маtеrialism.,'Thе proЬlеm, Brеwstеr gloomily сonсlr-rdеd, w:rswith thе slilсkrrеssоf modеrn еd. ..Prophеtiс цсation. of infidеl timеs, :lnd indiсаting thе unsоr.rrrс{nеss of our .Tlrе gеnегalеduсаtion, Vеstigеs' . .' Ьas startеdinto puЬliс favour with а faiг сhanсе of poisoning thе for.lntainsof sсiеnсе,and of sapping thе foundations of rеligion'' (Brеwstеr 1844' 503). \Х/illiam !Иhеwеll, anсlthеr of Darwin's mеntors' сollесtеd passagеsfгсlm еarliеr writings dеsigrlеdto show thе falsity of еvolutionary thinking. In tlrе first еdition of this сollссtion, Indiсаtiolls of tbe Сrеаtor (1845), hе did n()tеvеn mеntion VеstigesЬy n:rmе. To thе сontrary' thе pсlесAlfrесl Tеnnyson, rеad Vesrцr's (tlr morе proЬaЬly a dеtailеd rеviеw), аnd dесidесlthat it оffеrеd hopе that pеrhzrpsthе dеath of his dеar friеnd Artirur Hаllсrnrhad nсlt Ьееn iп vаit-tllnd thаt thе nihilisrrrof

Lyеlliаn gеology,showing сould Ье сonquеrеdЬy thс First tlrе dеspair:

Arе Gt

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Soс So саг ( . . S oс а

Fron S h еr l с l l г еi

..rеd in tot Givеrr naturе hеrе (stanzаlУ)-nothin1 Pеrhaps Hallam wаS an a

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UndouЬtеdly, somеthi thе Quееn on down-prс p u Ь l i с . r t i o no f r h е o r ц i l idеa. Anс1if this wеrе ntl frеd Russеl .Wallaсеrеaс lrnd dеvotеd thе rrехtdес disсovеrеd natural sеlес spllr[еd' Darwin wrotе t and truly launсhеd. BlвLIoGRAPHY

Vсstigе D. l 84,+. Bгеwъtеr. СhamЬеrs,R. 1844.Vesllg |81,S.F,хplапаtit Сrеаtitlп..'Lсlndon:Сt

Vеstigеsof thе NаturаrlHistory of Сrеаtion ,orlds.СhamЬеrs movеd nехt to l. In his Priпсiplеs of Gеologу Jеan-BaptistеLamarсk's thеory it as an answеr to thе upwardsaid nothing on this suЬjесt, Ьut l, and СhamЬеrs was nothing if tе prсrgrеssionfr
Lyеllian gеоlogy' showing ехtinсtion and appаrеntiy without hopе of progrеss' сould Ье сonquеrеdЬy thе uplifting mеssagеof Уеstigеs(Ross 197З). F.irstthе dеspair: Arе God and Nаturе thеn at strifе' That Naturе lеnds suсh еvil drеams? So сarеful of thе typе shе sееms, So сarеlеssof thе singlе lifе; . . . (Tеnnyson 1850' stanza LIV, 78) ..So

сarеful of thе typе?'' Ьut no. F.rom sсapеd сliff and quаrriеd stonе Shе сries ..a thousand typеs arе gonе: I саrе for nothing, all shall go.'' (Tеnnyson 18.50,stanza LV, 80) Givеn naturе ..rеd in tooth and сlaw''-this famor-rsphrаsе has its sourсе hеrе (stanzaLV)-nothing sееmsto makе any sеnsе.But thеn сamе thе hopе. Pеrhaps Hallam was an advanсеd form Ьorn Ьеforе his timе. A soul shall strikе frtlm сlut thе vast And strikе his Ьеing into Ьounds, And movеd thro' lifе of lowеr phasе, Rеsult in man, Ье Ьorn and think, And aсt and lovе, a сlosеr link Bеtwiхt us and thе сrowning raсе. . . . ( T е n n y s o n1 8 5 0 ' С o n с l u s i o n ,2 0 9 ) \й/hеrеofthе mаn, that with mе trod This planеt, was a noЬlе typе Appеaring еrе thе timеs wеrе ripе, Тhat friеnd of minе who livеs in God. ( T е n n y s o n1 B 5 0 , С o n с l u s i с l n ,2 1 0 ) UndouЬtеdly' somеthing likе this-thе poеm w:rs lоvеd Ьy еvеryonе,from thе Quееn on down-prеparеd thе way for Darwin. By 18.59,thе dаtе of thе puЬliсation of tЬе Оrigiи, еvolution was simply no longеr that shoсking аn idеа. And if this wеrе not еnсrugh,thеге is good еvidеnсethаt thе young Alfrеd Russеl \Wаllaсе read Vеstiges, Ьесamе an instant сonvеrt to еvolution, and dеvotеd thе nехt dесadе to finding a сausе.In 1858 hе was suссеssful:hе disсovеrеdnaturаl sеlесtion and sеnt his еssay to Сharlеs Darwin, and thus spurrеd, Dаrwin wrotе thе Оrigiп in fiftееn months and еvolution was wеll and truly launсhеd. в|вLIoGRAPHY Brеwstеr,D. 1844.Vеstigеs. Nоrth BritishRеuiеttl3:470_5.l5. Сhaпrbеrs,R. 1844. Уеstigеsof thе Nаtиrаl Historу of Сrеаtirlп.[,ondon:Сhurсhill. 1845.Ехplапаtiotts:А Sеquеlto ,,Vеstiges сlf thе Nаturаl Historу сlf Сrеаtioп.''London:Сhurсhill.

895

896

Vriеs Dаrwin, с. l859. Оп tbе Оrigiп of Spес.jс,.s. London: John Мurrаy. l,аtrrzrrсk, J.-B. 1809. Pbiltlsсlуlhiеzooklgiquе. Pаris: Dеntu. L,vеll, С. 1830-l8ЗЗ' Prinсiples of Gсrllogу: Bеing ап Аttеmpt to Ехplаill tbе Formеr Сhаngеs in thе ЕаrtЬ's Surfасе bу Rеfеrепсе to Сацses Notu iп Оpеrаtion.3 vols' l-orrdоn:John N,lurray. МсKinnеy, T1.L. 1972. Wаllасе апd Nаturаl Sеlесtiсlп.Nеw Havеn' СT: Yalе Univеrsity Prеss. .,Iп Rсlss, R. H. 1973. Alirеd' Lord Теппуsсltt: Меmсlriаm'.: Ап Аuthсlritаtiuе Техt, Bасhgrouпds апd Soиrсеs of Сritit:ism. Nеw York: Norton, Rr:sе, М. 1996. Мtlпаd to Мап: TЬе Ссlnсеpt of Progrеss in Еuсllцtioпаrу Biologу, Сambridgе, МA: Harvаrd Univеrsity Prеss. ,Гooth 1999. Thе Dаrшiпiап Rеur.llutklп:Sсiепсе Red iп апd Сlаш.2nd еd. Сhiсаgo: Univеrsity of Сhiсago Prеss. Sесord, J. A. 2000. Viсtoriап Sепsаtiсlп:Thе Ехtrаordiпаr1' Pнbliсаtioп' Rесе|ltiсlll, ,,Vеstigеs tlf thе NаturаI Historу oi Сrеаtioп''' апd Sесrеt Auth
Vriеs, Hugo dе (1848_19з5) Tоday Hugсl dе Vriеs is bеst knowrr as onе of thе rеdisсovеrsof Mеndеl's lаws. His papеr' ..Das Spaltungsgеsеtzdеr Bastaгdе,''togеthеr with sirrrilаr studiеs Ьу Caгl Coгrеns аrrd Еriсh von Tsсlrеrmаk-Sysеnеgg, all puЬlishеd in 1900, mark thе Ьеginning of thе sсiеntifiсdisсiplinе t>fmodеrn gеnеtiсs.But in thе сoursе of his long аnd distinguishеdсarееr,dе Vriеs also madе signifiсant сontriЬutions to еvolutionary Ьiology, еspесially with his thеory of intеrсеllularpangеnеsis(1889) and' most importantly, with his mutation thеory (1901-1903), whiсh sеt thе stagе for tlrе dеЬаtе aЬor-rtthе natuге of еvolu. tionary сhangе аs еithеr gradual and сontinuous Or as disсontinuous alld pro.. с е е d i n gi n j u m p s ' . o r m u t a t i ( ) n s . Hugo dе Vriеs was Ьorn in Haarlеm, Thе Nеthеrlands, in 1848 into a prominеnt Dutсh family. Showing an еаrly fasсinatiоn with Ьotany, his intеrеst soon shiftеd to plant physiology and towаrd аn еxpеrimеntal approaсh to thе study of living systеrns.His dissеrtirtionat thе Univегsiry of Lеidеn foсusеd on thе гolе of tеmPеraturе on thе lifе proсеssеsin plants. In 1870 dе Vriеs movеd to Gеrmany to lеarn morе aЬout еxpеrimеntal plant .WiirzЬurg physiology, working for sеvеra1yеars in thе laЬoratory of Julius Sасhs' a lеading plаnt physiсllogist. Hе rеturnеd to Thе Nеthеrlands in 1878 whеn hе wаs сlffеrеdan appointmеnt at thе nеw[y foundеd Univеrsity o f A m s t е r d a m . D u г i n g t h е 1 8 8 0 s l r i s r е s е a r с hs h i f t е dt o q u е s t i o n sо f v a r i a tiorr and inhеritаnсе' ln his thеorv of intеrсеllular pangеnеsis hе updated Сharlеs Darwin's thеory of inhеritanсе and сomЬinеd it with rесеnt insights in сеll Ьiology. Dе Vriеs arguеd thаt thе nuсlеus сontains all hеrеditary faсtors in thе form of irrdеpеndеntpartiсlеs, whilе оnly a suЬsеt of thosе will Ь е а с t i v е i n t Ь е с v t o p l a s п -or f i n d i v i d u a l с е l l s , t l r u s p r o v i d i n g a m е с Ь a n i s t i с

ехplani1tion of Ьoth hеrе с a l l е d t h е s еp a r t i с l е sp a n i Fuгthеr ехpеriп.lеntal! prеdiсtaЬlе pattеrns Of in Меndеl's 1866 papеr сor pеas' dе Vriеs rеalizеd tlrс turе. This irisightmarks tl: егn gеnеtiсs.Howеvеr, dl gеnеtiсsЬесausеhе wаrsm formations than mеrеly t аnгs. Hе had fiгst ntlriс lаmаrсhiаnа, whiсh hе tt mеnts and oЬsеrvatiorrаn summarizеd his idеas in tl that spесiеsarе сharaсtеr that thеsеmutants rеprеs е i t h е г Ь е n е f i с i a lo r d е t r i n lеd гo a rеnеwеd inrегеstil D е V г i е s r е t i r е di n 1 9 l 8 a u n t i l h i s d е a t hi n 1 9 3 5 . в|BLIoGRAPHY

СorrеIrs,с. 1900.G. Меnd B. dеr RassеnЬastаrdе. 1 5 6 - 16 8 . Mеnсlеl,G. |866. Vеrsuсh паtu rftlsсhспdсп Vеrеin Е. von Tsсhеrmak-Sysеnеgg, Bеriсhtеder Dеutsсhе Vееr,P. dе,|969. Lеuепеlt Noordhоif. Vгiеs,Н. dе. 1889.]пtrасе l900. Das Spаltrrn DeutsсhепBotапisсhe 1 9 0 1 - 1 9 0 3D. i е М t

Еtttstсhuпg tцlп Аr!t'tt i

Уriеs con: John Мurray' ris: Dеntu. |g ап Аttеmpt to Ехplаiп thе .'fеrеnсеttl Саust's Nota iп lсlloz. Nеw Havеn, СT: Yalе еmoriа m'' : Ап А ut h orittttiuе Tехt, York: Norton. Progrеss iп Еuolutioпаrу Biologу. е Red iп Тooth апd Сlаш,.2nd ed. аordiп.trу Pцbliсаtiсlп, Rесеpl ioп, lturdl Нistorу of Сreаtioп.'' i2: 1-85. аrd Мoxon. s апd opiпioпs. London: Chapman lndon: Pаrkеr

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оf rhе rеdisсovеrsof МеndеlЪ }astardе'''togеthеr with similar rmak_Sysеnеgg, all puЬlishеd in ;сiplinе of modеrn gеnеtiсs.But 'rееr'dе Vriеs also madе signifi:spесiallywith his thеory of intantly' with his mutation thеory Ьatе aЬout thе nаturе of еvoluIusor as disсontinцous and proе N е t h е r l a n d s 'i n 1 8 4 8 i n t o a asсination with Ьotany' his inl toward an ехpеrimental apissеrtationat thе Univеrsity of L thе lifе proсеssеsin plants. In n o r е а Ь o u t е х p е r i m е n t a lp l a n t WiirzЬurg laЬorator}' of Julius urnеd to Thе Nеthегlands in .thе nеwly f o u n d е dU n i v е г s i t y t shiftеd to quеstions of variaеllular pangenеsis hе updаted lmЬinеd it with rесent insights :us сontains all hеrеditary faс. i l е o n l y a s u Ь s е to f t h o s е w i l l thus рroviding a mесhanistiс

е х p l a n a t i o n o f Ь o t h h е r е d i t 1 . a n dd i f f е r е r - r t i а t i o n I n. h o n o г o f D i r r w i n ' h е сal[еd thеsе partiсlеs pangеnеs. Furthеr ехpеrimеntal studiеs dеmonstratеd that thеsе faсtors followеd prеdiсtaЬiе pattеrns of irrlrеritanсе.Aftеr a сollеilguе sеnt him а rеprirrr of Mеndеl's 1866 papеr сontaining thе lattеr's nowtfаmous ехpеrimеnts with pеаs, dе Vriеs rеalizеd that thе laws of inhегitanсеarе of a morе gеnеraInilturе. This insight marks thе rеdisсtlvеryof Меndеl and thе Ьеginningof nrodеrn gеnеtiсs.Howеvеr' dе Vriеs did not partiсipatе in thе еstablishmеntof gеnеtiсsЬесausehе wаs morе intеrеstеdin aссotrntingf
8e7

Waddington,Conrad Hal (1905-1,975) Сonrad Hаl \trасldington Wz1sa pionееr irr linking dеvеlсlpmеntаl аrrd еvolutionary Ьiolog,v.Hе еxplorеd thе сеntral rolе of dеvеlсlpmеntin еvсllutionапd arguеd that natural sеlесtion moldеd dеvеlсlpmеntalproсеssеsthеmsеlvеsin diffеrеnt ways undеr diffеrеntеnvironmеntalсirсumstanсеs. lй/addingtonсаmе to thе еvolution of dеvеlopmеnt аftеr showing thаt sеvеral dozеn gеnеs intеrасtеd to gr'ridеdеvеloprrrеrrtof normal wiгrgs in tlrе fruit fl,v, Drosophilа. Tlris rеsult inspiгеd his сonсеpt of thе еpigеnеtiс (litеrаlly, Ьеyond gеnеtiсs)landsсapе, thе sеt of possiЬlе dеvеlopmеntal pathways for a struсturе inhеrеnt in thе nеtwork of ir-rtеraсtinggеnеs thаt prodr-rсеit. Waddington suggеstеd thаt nаtr'rr:rlsеlесtion would fаshiorr tlris nеtwork ttl insulаtе nоrmal dеvеlopmеnt frtlп-rthе disruptivе еffесtsof еxtеrnal pеrturЬations likе unfavorablе tеmpеraturеs or intеrnal pеrturЬations likе mutations, This insulation, сallеd сanalizаtion (sее figurе), W.ls a сharaсtеristiсof normаl dеvеlоprnеntthаt \Waddingtonsaw аs аn еssеntizrladaptivе propеrty of сlrgаnisms. Waddingtoll is known nrorе widеly for dеsсriЬirrga striking proсеssсallеd gеnеtiс assimilаtion thаt, at first glanсе, suggеstsa kind of nеo-Lаmarсkism. .Waddington's original ехpеrimеnts shoц,еdthat hеat shoсk during a сritiсal prесlrrсlеdformaсiorrof а small vеin in thе flv wing in phzrsеof dеvеlopп-rеnt somе individuals. Waddington ехеrtеd аrtifiсial sеlесtion for grеatеr еxprеsall individuals to hеat siсln in rеsponsе to hеаt slroсk; that is' hе suЬjесtес1 lасkеd thе vеin. As ех. shoсk Ьut sеlесtеdfor Ьrееding only individuals that rеspondеdto hеаt pесtеd,аftеr m:rrlygеnеrаtionsmorе and morе indiviсlr.rals slioсk Ьy rrot forming tlrе vеin' But thе unеxpесtесlrеsult wаs tlrat many individuals in thе sе|есtеdpоpulation failеd to forrn thе vеin еvеn whеn thеy wеrе not ехposеd to hеat shсlсk; еvеn morе surprising, thеir offspring fаilеd to -Гlrus forrrrthе vеin. a rеsponsеthat wаs fi.rсultativеаt thе start Ьесirmесonstitutivе; somеhow tl-rеgеnеs Ьad..аssiп-ri[аtеd''tlre rеsponsе to lrеat shoсk through sеlесtiorrof individtlаls that laсkеd thе vеin. \il/addingtonarguеd that this proсеss rеpгеsеntеda disruptiсlnof саnalization that сould Ье favorеd by fеагttrеimportatrt fсlr sur. naturаl sеlесtiorrЬесausе it :lllowеd a faсr.tltativе vivirl irr a novеl еnvironmеnt to Ье еxprеssеdсonsгitlltivеly. Although Waddington's ехplanatioп ftlr gеnеtiс assinrilationI.rilsЬееn supегsеdеdЬy sinrplеr onеs, his viеw оf dеvеlopmеntalsystеnrsas irrtеgralеlеA grеat dеal сlf rеsеarсh mеnts Of еvolution has Ьееn еmЬraсеd ur-rivеrsally. tсl systеr-n сvоlvеs sеtrsirir,itv hаs foсtlsеd on r'n,hеn and hou, 'r dеvеlсlorrrеntal 8e8

.Waddington Сonrad Hal sсiеntifiсidеas.This figur h o w Ь i s i d е аo f с а l l а | i z a dеvеlopnorrтallydеspitе thе sidе of thе vallеy).But havе lzrstingеffесts.Thеrе landsсapеs,and as r"rotеr n h j sс h o i w а s i г r f l u е n с еi d

and not insulation from ..Phеnotypiсplastiсity'' i tеms thеmsеlvеshаs Ьес ..Еvolш thе mаin еssаv v o l u m е ) ,а n d е p i g е n е t i rapidly growing and ехс !7addington lеft аn еn еmЬгyology and dеr,еlo also hеlpеd Ьuild thе lns Ьurgh into onе of thе w his еntirе сarееr on thе l Rоyal Soсiеty of ЕdinЬu of Arts and Sсiеnсеsin 1 в|BLIoGRAPHY

W а d d i r r g t t -с' .n H . . lq,;'. , o|,Тheorсtiсаl Bit itlg1

Wаddiпgton

r75 'l nking dеvеlopmеntal and еvoluof dеvеlopmеntin еvolution and pmеntal proсеssеs thеmsеlvеs in сirсumstanсеs. )pmеntaftеr showing that sеvеral of normal wings in thе fruit fly, f thе еpigеnеtiс(litеrally, bеyond lmеntal pathways for a struсturе hat produсе it. Waddington sugs nеtwork to insulatе normal dеLalpеrturЬationslikе unfavoraЬlе Iutаtions.This insulation, сallеd iс of normal dеvеloрmеnt that еrty of organisms. сriЬing a striking proсеss сallеd ,еstsa kind of nеo-Lamarсkism. hat hеat shoсk during a сritiсal , f а s m a l lv е i n i n t h е f l y w i n g i n :ial sеlесtionfor grеatеr ехрrеsuЬjесtеdall individuals to hеat rals that laсkеd thе vеin. As ех:е individuals rеspondеd to hеat есtеdrеsult Was that many indim thе vеin еvеn whеn thеy wеrе rising' thеir offspring failеd to Lltativеat thе start Ьесamе сonэd'' thе rеsponsе to hеat shoсk rеvеin. \7addington arguеd that ization that сould Ье favorеd Ьy ltivе fеaturе iпrportant for surсonstitutivеly. :nеtiсassimilation has Ьееn suэmеntal systеmsas intеgral еlеrsally. A grеat dеal of rеsеarсh r a l s y s t е mе v o l v е ss е n s i t i v i t yt o

.Waddington of Was partiсularlyintеrеstеdin visual rеPrеsеntations Сonrad Hal sсiеntifiсidеas.This figurе,tаkеn from Тhе Strаtеgуof thе Geпеs (1957), shows .Within how his idеa оf сanalization works. сеrtain limits, thе organism will dеvеlopnormаlly dеspitеdisturЬanсеs(in thе piсturе,thе Ьall Ьеingpushedup thе sidе of thе vallеy).But thеrеarе сhoiсеs,and too grеat a disturЬanсеwill hаvе lasting еffесts.Thеrе arе oЬvious hints hеrе of lWright'sadaptivе .Wright landsсapеs,аnd as notеd еlsеwhеrеin disсussionof thеm' it may Ье that .Waddinяton. wаs influеnсеdin his сhoiсе of mеtаphorЬy

and not insulаtion from еnvironmеntal influеnсеs(sееthе alphaЬеtiсalеntry ..Phеnotypiсplastiсity'' in this volumе). Thе еvolution of dеvеlopmеntalsystеms thеmsеlvеshas Ьесomе an importаnt topiс in еvolutionary Ьiology (sее ..Еvolution thе main еssay and Dеvеlopmеnt'' Ьy Grеgory A. Wray in this volumе)' and еpigеnеtiсsand dеvеlopmеntal nеtworks аrе two of thе most rapidly growing and еxсiting arеаs of modеrn biology. \й/addingtonlеft an еnduring lеgaсy Ьеyond his rеsеarсh. His tеxtЬooks in еmЬryology and dеvеlopmеntalеvоlution guidеd gеnеrationsof studеnts.Hе also hеlpеd Ьuild thе Institutеof Animal Gеnеtiсs at thе Univеrsity of Еdin.Waddington spеnt nеarly Ьurgh into onе of thе world's lеading institutions. his еntirе сarееr on thе faсulty аt ЕdinЬurgh and was еlесtеd a fеllow of thе Royal Soсiеty of ЕdinЬurgh in 1948 and a fеllow of thе Amеriсan Aсadеmy of Arts and Sсiеnсеsin 1959. B|вLIoGRAPHY Waddington,с. H. 1957, Тhе Strаtеgуof thе Gепes:A Disсussioпof SсlmeАspесts Allеn & Unwin. of Theoretiсаltsioltlgу.l,ondon:

899

900 Wаdе 1'975.Thе Еuсllutklп of ап Еuolиtil,rrlsf.Ithаса, NY: Сoгnе|l Univегsity Prеss. .!Иеst.ЕЬеrhard' М.J. 200З. Dеuеklpmепt.ll Plаstiсitу апd Еurllиtitlп.Nеw York: -] .Т. oxford Univеrsity Prеss.

.Wadе, Мiсhaеl John (ь. 1949) Мiсhaеl John \Х/adеis аn Amеriсan еvolutionary gеnеtiсistwho usеd flour Ьееtlеs of thе gеnus Triboliцm, as wеll as thеOrrtiсal modеls, to invеstigatеgroup (or intеrdеmiс) sеlесtion, kin sеlесtion, Sеwall \Wright's..shifting Ьalanсе'' thе. ory, sеxual sеlесtion, еspistasis,matеrnal gеnеtiс еffесts,and spесiatiсln. .Wadе Thе oldеst of еight сhildrеn' studiеd Ьiolоgy and mathеmatiсs at Boston Collеgе, graduating in 1971. Intеrеstеdin ссlmЬining mаthеmatiсs .V7adе wеnt to thе Univеrsity сlf Сhiсago's now-dеfunсt Thеоrеtand Ьiology' iсal Biology program for gгaduatеwork. Сoadvisеd Ьy thе population Е]еnеtiсist Мontgomеry Slatkin and thе есologist Thomas Park, .й/adесonduсtеd thе first еxpеrimental study of group sеlесtion Ьy sеlесting flour ЬееtlеsЬasеd not on individual сharaсtеristiсsof thе Ьееtlеs,ЬLlt on aspесtsof thе pсlpulations from whiсh thеy arosе. A strong геsponsеtсl sеlесtionwas еvidеnt аftеr only thrее gеnеrationsof sеlесtion:populations in linеs sеlесtеdfoг high population sizе and thosе sеlесtеdfor low pоpulatiсlnsizе еvolvеd suЬstantialdiffеrеnсеs,showing that intеrdеmiс sеlесtionсould Ье а powеrful еvolutionary forсе. at lеast undеr сеrtain сonditions. From 1975 to 1998 \й/adеhеld a position at thе Univеrsity of Сhiсago, first in thе Biology Dеpartmеnt and сr-rlminatingas сhair of Есology and Еvolution (1991_1998).Hе movеd to his prеsеntposition at thе Univеrsitу сlf Indianа in 1998. In 1980 \)Иadесonduсtеd thе first ехpеrinrеntal tеst of kin sеlесtion,oЬsеrving that сanniЬalism in flour Ьееtlеsеvolvеd along diffеrеnt еvolutionary trajесtoriеsdеpеnding on pattеrns of gеnеtiс rеlatесlnеssdеtеrminеd Ьy thе mating systеm.\й/adеand his studеnt Сharlеs Goсldnight usеd ..shiftingЬalanсе'' laЬoratory mеtapopulationsto tеst thе еffiсaсyof \Wright's thеory, a modеl of еvсllution tlrat involvеs randoп-tgеnеtiс drift rеsulting in pеak shifts in loсal suЬdividеd populatiсlns and thе sprеad of nеw, irdaptivе gеnе сomЬinations aсross thе largеr population via migrati
of thе еvolution of еuso h y p o t h е s i s .H i s t h е o г е r tasis within populations l а t е d p o p u I a t i o n s с' o n t r в|вLloGRAPHY

Dеmuth,J. P.' and M.J. !и intеraсtions.Аппuаl R 289-316. .!7adе, M. J. 1977. An ехpе 13 4 - 1 5 3 . \'Vadе, М. J., and С. J. Goo еxpеrimеntalstudy'Sс 1 9 9 8 .P е r s p е с t i v mеtapopulations: W.hе l5з7_15.53.

.W.akе, David B. (Ь.

.!7akе David is onе of Aг o u s г е s е a r с hс o n t r i Ь u t i o parativе morphology, l есology, Ьiogеographу,p s y s t е m a t i с sa. n d p h y I o g and ovеrarсhing intегеstl duсе thеm. Although thе of еvolutionary divеrsifiс .VИakе,s еmpiriсal work hl ary linеagе, thе lunglеss through thе еfforts of V ovеr thе nеarly fivе dесa tury аnd сontinuе into th thе most сomprеhеnsivе adaptivе radiatiсln in thе David Burton.V7akеwа Muсh of thе Uppеr Мidv Ь y S с a n d i n а v i a ni m m i g r turiеs, and Ьoth of !Иakе o f l 7 W a k е r е l o с a t е dw i whеrе hе сomplеtеd prес drеn of Sсandinavian rп timе, !Иakе еnrollеd at Pz vеrsity), whеrе hе сomрlt From thеrе hе advanсеd Southеrn Сalifornia (US( pеrvision of Jay M. Savа

\ilаkе /. Ithaсa,NY: Сornеll Univеrsity tstiсitуt]пd Еuсllutiсlп. Nеw York:

-].Т,

of thе еvolution of еusoсiality in thе Hymеnoptеra than thе haplo-diploidy hypothеsis.His theorеtiсalstudiеsof gеnе intеraсtionshavе shown how еpistasis within populations сan aссеlеratеthе adaptivе divеrgеnсе Ьеtwееn isolatеd populations, сontriЬuting to spесiation. BIBLIOGRAPHY

)nary gеnеtiсistwho usеd flсlur Ьеег е t i с аm I o d е | s t' o i n v е s t i g a t еg r o u p .Wright's..shifting all Ьalanсе'' thе. .nеtiсеffесts'аnd spесiаtion. diеd Ьiology and mathеmatiсs at rеstеd in сomЬining mathеmatiсs lf Сhiсago'snow-dеfunсt Thеorеt]oаdvisеdЬy thе population gеnеst Thomas Park, .Wаdе сonduсtеd ion Ьy sеlесtingflour ЬееtlеsЬasеd ltlеs,Ьut on aspесtsof thе populaonsе to sеlесtionwаs еvidеnt aftеr гionsin linеs sеlесtеdfor high poprlation sizе еvolvеd suЬstantial difLсould Ье a powеrftrlеvolutionary 1 at thе Univеrsity of Сhiсago, first rg as сhair of Есology аnd Еvoluг position at thе Univеrsity of Indithе first еxpеrinrеntal tеst tlf kin lur Ьееtlеsеvolvеd along diffеrеnt :tеrnsof gеnеtiсrеlatеdnеssdеtеrs studеntСhаrlеs Goodnight usеd :aсyof Wright,s ..shiftirrgЬalаnсе'' i random gеnеtiс drift rеsulting in s and thе sprе:rdof nеw' :rdaptivе ation via migration and sеlесtion. :rmеdiatеlеvеls tlf drift аnd intеr. ,rеtiсаlсontгiЬutions. Hе was thе :ndеr kin sеlесtionсould Ье parti: within and among kin groups. In i a nесеssaryrеlatiоnship Ьеtwееn lеs and that in fсmalеs, ехplаining lany timеs grеatсrthan that aсting tatеrnalеffесtsеvolvе muсh mtlrе oids and, with his {ormеr studеnt, ts thеоryprovidеsa Ьеttеraссount

Dеmuth'J. P., аnd М. J. \7adе.2006.Еxpеrimеntаlmеthodsfor mеasuringgеnе intеraсtions.Anпuаl Rеuiеtuof Ессllсlgу,Еuolиti
Wakе, David B. (b. 1936) David lWakе is onе of Amеriсa's lеading еvolutionary Ьiologists.His numеrous rеsеarсh сontriЬutiоns span many fiеlds' inсluding funсtional and сomparativе morphology, Ьеhavior, dеvеlopmеntal Ьiology аnd ontogеny, есology' Ьiogеography,population gеnеtiсs,molесular еvolution, taхOnomy' systеmatiсs,and phylogеny. Thеsе studiеs havе bееn motivatеd Ьy a сеntral and ovеrarсhing intеrеstin еvolutionary pattеrns and thе proсessеsthat produсе thеm. Although thе goal has Ьееn to idеntify and ехplorе mесhanisms of еvolutionary divеrsifiсationthat arе Ьroadly appliсaЬlе to all organisms, .$7akе's еmpiriсal work has foсusеd аlmost ехсlusivеly on a singlе еvolutionаry linеagе, thе lunglеss salamandеrs of thе fаmily Plеthоdontidaе.Largеly .!fakе through thе еfforts of and his numеrous studеnts and сollaЬorators ovеr thе nеarly fivе dесadеs that spannеd thе lаst half of thе twеntiеth сеntury and сontinuе into thе twеnty-first, plеthodontid salamandеrs arе onе of thе most соmprеhеnsivеly invеstigatеd and fully doсumеntеd instanсеs of adaptivе гadiation in thе history оf еvolutionary Ьiolоgy. .V7еЬstеr' Dаvid Brrrton lWakе was Ьorn on Junе 8,19з6, in South Dakota. Muсh of thе Uppеr Мidwеst of North Amеriсa had Ьееn ехtеnsivеlysеttlеd Ьy Sсandinavian immigrants in thе latе ninеtееnth and еarly twеntiеth сеnturiеs, and Ьoth of \Иakе's parеnts wеrе of Norwеgian dеsсеnt.At thе agе of 17 Wakе rеloсatеd with his immеdiatе family to Taсoma, N7ashington, whеrе hе сomplеtеd prесollеgiаtе еduсation. As was typiсal of many сhildrеn of Sсandinavian immigrants living in thе Paсifiс Northwеst at thе timе,.Ufakееnгollеd at Pасifiс l,uthеran Сollеgе (now Paсifiс Luthеran Univеrsity)' whеrе hе сomplеtеd his undеrgraduаtе dеgrее in Ьiology in 1958. From thеrе hе advanсеd to graduatе sсhool in Ьiology at thе Univеrsity of Southеrn Сalifornia (USС) in Los Angеlеs, whеrе hе workеd undеr thе supеrvision of Jaу М. Savаgе for Ьoth mastеr's (1960| and doсtoralr (1964I

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Wаkе dеgrееs.Savagе,a lеading tropiсal есоlogist аnd Ьiogеogrаphеr,was at that timе launсhing а Ьroad resеarсh еffort on amphiЬians and rеptilеs of Сеn.sИakе's intеrеsts in plеthodontid tral and Soцth Amеriсa, and hе promotеd salamandеrs, whiсh havе thеir prinсipal spесiеs divегsity in thе nеotropiсs. Savagе'sсlosе аssoсiаtion with thе Los Angеlеs Сounty Мusеum of Natural Histoгy also providеd Wakе with valuaЬlе еxpеriеnсе with rеsеаrсh сollесtions in hеrpеtology and faсilitatеd his еаrly studiеs in taхonomy and sys. tеmatiсs. .Wakе lеft USС in 7964 to assumе his first full-timе aсadеmiс position, at thе Univеrsity of Сhiсago, whеrе hе rеmainеd for fivе yеars. In |969 he returnеd to Сalifornia to join thе Zoology Dеpartmеnt faсulty at thе Univеrsity of Cаlifornia, Berkеlеy,and Ьесomе сurator of hеrpеtologyat Bеrkеlеy'sMusеum of VеrtеЬratе Zoo1ogу wLУZ). This Ьеgan a long and produсtivе asso. сiation with thе NLУZ, whiсh NИakе sегvеd as dirесtor for 27 yеars until 1998. Undеr.Wakе's dirесtiоn thе МVZ Ьесamе onе of thе world's leading сеntеrs for rеsеarсh and tеaсhing in еvolr.rtionaryЬiology. .s7akе's In purеst tегms rеsеarсh addrеssеsa fundamегltalquestion in еvolutionary biology: why arе thеге so many diffеrеnt kinds of organisms? His work has Ьееn influеntial Ьесausе it ехеmplifiеs a сoпrprеhеnsivе approaсh to analysis of еvolutionary divеrsifiсation that еvaluatеs thе rolеs of Ьoth еxtrinsiс and intrinsiс faсtors and simultanеouslyсonsidеrs a widе rangе of Ьiologiсal attriЬutеs,from molесulеsto organisms and thеir еnvironmеnts.Thе study of еvolution sinсе thе modеrn synthеsishas until гесеntly foсusеd largеly on ехtrinsiс faсtors as dеtеrminants of еvolutionary сhangе, suсh as thе rolе of thе ехtеrnal еnvironmеnt in mеdiаting natural sеlесtion for adaptations. 1$Иаkе's work has highlightеd thе nееd for сomplеmеntary studiеs that еvaluatе thе potеntial rolе of intrinsiс faсtors' Suсh as linеagе-spесifiсdеvеlopmеntal traits or сonsеrvеd anatomiсal fеaturеs, whiсh may Ьoth faсilitatе and сonstrain divеrsifiсationin signifiсantWays. A full undеrstandingof thе еvolution of any taхon is likеly to rеquirе suсh а holistiс approaсh, whiсh inсorporatеs all rеlеvant information. !Иakе is thе author of morе than 250 pееr-rеviеwеdpuЬliсations,as wеll as popular artiсlеs and Ьooks. Hе has rесеivеd numеrous honors and awards' inсluding еlесtiоn to mеmЬеrship in thе U.S. National Aсadеmy of Sсiеnсеs in 1998. BlвLIoGRAPHY Wakе,D. B. |997,Inсipiеrrt spесiеsforпratioпin salamarrdеrs of thе Епsаtiпа сomplеx.Procеedingsof thе Nаtionаl Асаdеmуof SсiепсеsUSА 94 7761-7767. .!Иаkе, D. B., and A. Larson.1987.Multidimеnsiоnаl analysisof an еvolvinglinеagе. Sсieпсе2З8: 4248. Wаkе,D. B., and J. F. Lynсlr.1976.TЬedistriЬution, есology,and еvolutionary history of plеthodontidsаlamandеrsin tropiсаlAmеriсa.SсiепсeBtilеtiп, -I rt Nаtиrаl Historу Миsеum of Lсls Апgеles Сouпtу 25l I_65.

.Wallaсе, Alfrеd Ru

Alfrеd Russеl !Иallaсе ц ogists of thе ninеtееnth marily upon his disсovе еvolцtion Ьy natural sе prolifiс gеnеratorof idе ary Ьiology to soсiаl an l а i d s o m е o f r h е r n а i ni с and Ьotany. Bу 1844 thе 20-yеar. array of loсal British plz plishеd еntomologist,B; of Ьotany to a moге gеnе \Wallaсеrеad Сharlеs Lyс RoЬеrt СhamЬеrs's (th Сrеаtioп (1844), Willia Phуsiologу' Zoolсlgу, аr Darwin's Voуаge of thе i m p I i с i t l y ,w i t h е v o l u t i o distrilэutionof animаls а riеtiеs. \ffhеn Batеs and m a d е г h е f а t е f u ld е с i s i o gland on April 26, 1848 thе fiгst of thе two tropiс thе еmеrging sсiеnсеof of thе Amazon Ьasin of London. Hе puЬlishеdА (1853)' whiсh еstаЬIis gеogгaphiс distriЬution nition that thе distriЬut surprisingly prесisе and асhiеvеmеntof his Amаz сommittеd to somе foгm not yеt prеparеd to posit of Trаuеls. Сorrvinсеd that аnothе of prоviding thе dаta rе tеrmеd thе spесies problе onеs), \Jfallaсе dесidеd o rivеd in Singapore on Apl irr rhе islands of Jаva, Bо smallеr islands in thе аrсЬ 14'000 milеs аnd соllесt spесimеns.Hе еnсountеr

'Wаllаce lnd Ьiogеоgraphеr,was at that nphiЬians and rеptilеs of Cеn/аkе'sintеrеstsin plеthodontid : i е sd i v е r s i t уi n t h е n е o t r o p i с s . [еsСounty Musеum of Natural xpеriепсеwith rеsеarсh сollес.studiеs in taхonomy and sysfull-timе aсadеmiс position, at d for fivе yеars. In 1969 Ьe re' r t m е n tf a с u l r ya t t h е U n i v е г s i t y f hеrpеtology at Bеrkеlеy's Mu; a n а l o n g а n d p r o d u с t i v еa s s o as dirесtor for 27 yеars until amе one of thе world's lеading ary Ьiology. a f u n d a m е n t a lq u е s t i o n i n е v o :fеrеntkinds of organisms? His эs a сomprеhеnsivе approaсh to еvaluates thе rolеs of Ьoth ехly сonsidеrsа widе rangе of Ьims and thеir еnvironmеnts. Тhе las until rесеntly foсusеd largеly :ionary сhangе, sцсh as thе rolе tuгal sеlесtion foг adaptаtions. nplеmеntary studiеs that еvaluаs linеаgе-spесifiсdеvеlopmеnwhiсh пray Ьoth faсilitatе and \ full undеrstanding of thе еvoholistiс appгoaсh, whiсh inсorеviеwеdpubliсations, as wеll as numеrous honors and awaгds. Nationa] Aсadеmy of Sсiеnсеs

alаmandеrs of thе Епsаtiпа cу of Sciепсеs USА 94: nal analysis of an еvolving linеagе. эn, есology' and еvolutionary rl Amеriса. Sсiеnсе BuIlеtiп,

пtу 25 1-65.

-1.H.

Wallaсе,Alfrеd Russеl(1823-19ТЗ) Alfrеd Russеl !ИallaсeWas onе of thе nrost brilliant thеorеtiсaland field Ьiоlogists of thе ninеtееntlrсеntury. Нis famе in thе lristory of еvolution rеsts pгimаrily upon his disсovеry,indеpеndеntlyof Сhaгlеs Darwin, of thе thеory of еvolution Ьy natural sеlесtion. Wallaсе Was a mеtiсulous fiеld oЬsеrvеr, a prolifiс gеnеratorof idе:lson a Ьгoаd rаrngеof issuеsranging from еvolutionary Ьiology to soсial and politiсal сonсеrns, and a thеorеtiсian whosе work lаid sonrе of thе main foundatior-rsfor the sсiеntifiсstudy of modеrn zoology and Ьotany. Bу |844 thе 2O.yеar-old \Vаllасе had сollесtеd and аnalyzed an ехtеnsivе arraу of loсal Bгitish plаnts. In 1B44 hе mеt Hеnry lWaltегBatеs. An aссomplishеd еntomologist, Batеs еnсouragеd !Иallaсе to movе Ьеyond thе Ьounds of Ьotany to а morе gеnеral study of natural history. Drrring thе nехt fеw yеars NИallaсеrеad Сharlеs Lyеll's thrее-volumе Priпсiplеs of Gеologу (1830_18з3), Robеrt СhamЬеrs's (thеn-anonymous) Vestiges of the Nаturаl Historу of Сrеаtirэrt (1'844), Williаm [-awrеnсе's Lectцres ort Сompаrаtiuе Апаtomу, Pbуsiologу, Zoolrlgу, апd tlle Nаturаl Historу of Маn (1819), and Сhaгlеs Darwin's Voуаgе сlf the Bеаgle (1839)-works that dеalt, еithеr еxpliсitly or impliсitly' with еvolutionary spесulatiоns' thе origin of spесiеs' thе gеographiс distriЬution of animals аnd plants, and thе diffеrеnсеЬetwееnspесiеsand va,J'847, riеtiеs. !7hen Batеs and.Wallaсе mеt again in the summer of thе two .Wallaсе madе thе fatеful dесision to journеy to thе tropiсs. and Batеs lеft Еngland on Дprll 26,1848, dеstinеd for Pаr6 (now Bеlёm),Braztl' Thus Ьеgan thе fiгst of thе two tropiсal journеУs that wеге to transform !Иallaсе's lifе and thе еmеrging sсiеnсе of еvolutioпary Ьiology. Aftеr a fouг.yеаr еxploration of thе Amazon basin of Sorrth Amеriсa (1848_1852). \Wallaсеrеturnеd to London. Hе puЬlishеd А Nаrrаtiuе of Trаuels oп thе Аmаzoп апd Riсl Negro ( 1 8 5 з ) , w h i с h е s t a Ь l i s h е dh i s r е p u t a t i o n a s t h е f o r е m o s t a n a l y s t o f t h е gеographiс distriЬution of animаls and plants (Ьiogеography).Thе reсognition that thе distriЬrrtion of сlosеly alliеd spесiеs was oftеn markеd Ьy surprisingly pгесisе and aЬrrrpt barriеrs Was thе most important sсiеntifiс aсhiеvеmеntof his Amazоnian tr:rvеls.Howеvеr, although lfallaсе had Ьееn сoпrmittеd to somе fornr of gеnеrаl еvсrlutionarythеory sinсе 1845, hе was not yеt prepаrеd to posit an ехpliсit еvolutionary mесhanism jn А Nаrrаtiuе of Тrаuеls. Сonvinсеd that anothеr voyagе of ехploration was thе most сеrtain mеans of providing thе data rеquirеd for thе thеoгеtiсal еluсidation of what was tегmеd thе spесiesproblеm (i.е.' how nеw spесiеsoriginatе from рrееxisting .!7allaсе onеs)' dесidеd on an ехpеdition to thе Мalay Arсhipеlago. Hе arrivеd in Singаpоrе оn April 24,1854, to Ьеgin еight yеars of intеnsivеtravеls in thе islands of Java, Borneo' СеlеЬеs, Nеw Guinеa, and Bali and in many smаllеr islands in thе arсhipеlago.Frorn 18.54to 1862 Wallaсе сovеrеdnеarly 14,000 milеs and сollесtеd thе vast amount of 125'000 (primarily faunаl) spесimеns. Hе еnссruntеrеdаnimals' Ьirds, аnd insесts in Ьеwildеring vаriеty

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'WаlIасе and aЬundanсе' many of whiсh had not Ьееn prеviously sееn Ьy Еrrropеans. !Иallaсе also oЬsеrvеd аnd lived with гhе divегsеЬuman ir-rhaЬitants of thosе rеgions. $7allaсе'soЬsеrvations on thе gеographiс distriЬution of spесiеslеd him to nеw insights aЬout еvolutionary history. Не proposеd that thе spесiеs in thе wеstеrn half of thе Маlay Arсhipеlago wеrе ovеrwhеlmingly Indian in origin' whеrеas thosе in thе еastеrn hаlf wеrе prеdonrirrantly of Austrаlian origin. This was a bold synthеsisof еvolutionary thеory and сopious fiеld oЬsеrvation. Thе faunal disсontinuity that sеparatеs thе Indian from thе Australasian sеgmеnts of thе arсhipеlago is сallеd !Иallaсе's linе in his honor. .s7allaсе latеr gеnеralizеd thеsе сonсеpts to еlaЬoratе a gloЬаl pаradigm for idеntifying thе еarth's fundamеntal Ьiogеographiс rеgions in his magistеrial .Wallaсе's Gеogrаphicаl Distributioп of Апimаls (1876). Dеtaiis of original Ьiogеogгaphiс rеgions-and thе prесisе loсation of thе Ьoundary first sug. gеstеd by W.allасе'slinе-trndеrwеnt rеvision аs morе аЬundаnt data Ьесаmе availablе during thе twеntiеth сеntury. Thеoriеs of сontinеntal drift havе also .Wallaсе's rеquirеd a rеintеrprеtation of сеrtain of ninеtееnth-сеnturyprеmisеs. Nonеthеlеss, his Ьiogеogrаphiс synthеsis stirnds as a major dеvеlopmеntin еvolutionary Ьiology and сontinuеs to int]uеnсесontеmporary Ьiogеographiс studiеs. .!Иallaсе's It is, of сoursе' еluсidation of thе mесhanism of еvolution that сonstitutеs his grеatеstsсiеntifiс lеgaсy fгom thе Мalay trаvеls. In 1855 hе puЬlishеd thе fаmous еssay ..on thе Law \Х/hiсhHаs Rеgulаtеd thе Intro.Wаllaсе laid thе foundаtions for what duсtion of Nеw Spесiеs.'' In this еssay would shortly Ьесomе his ехpliсit statеmеnt of thе еvolutionary thеory. !Иallасе сonstruсtеd a powегful argumеnt in support of thе thеsis that nеw spесiеs arisе naturally from сlosеly rеlatеd, prееxisting spесiеs,but hе suggеstеd no mесhаnism for suсh сhangе. From 1855 to 1858 !Иallaсе sеnt to Еngland sеvеral aгtiсlеs on thе flora and fauna of thе islands hе visitеd and dеalг ехpliсitly with thе thеorеtiсal impliсаtions of thе 1855 law' Finally, in FеЬruary 1858-rесalling pаssаgеs from Thomas Мalthus's Еssау oп thе Priпciple of Populаtioп (1798), with its vivid dеpiсtion of thе сompеtitivе strugglеs for survival among human populations-thе prinсiplе of natural sе.Wаllасе's lесtion еmеrgеd in mind as thе kеy mесhanism of еvolutionary .Wallасе сhangе. For еvolution Was a two-stеp proсеss: first' thе appеaranсе of variations (latеr сallеd mutations) in individual mеmЬеrs of a spесiеs'and .Wallaсе sесond, thе sorting out of this variation Ьy natural sеlесtion. arguеd thаt thе еxistеnсе of beritаble variations within a spесiеs,сouplеd with thе produсtion of morе offspring than сould possibly survivе (givеn thе сonstraints of thе еnvironmеnt' suсh as food supply), сonstitutеd thе сonditions undеr whiсh favoraЬlе vаriations tеndеd to Ье prеsеrvеd аnd injurious variations еliminatеd. ovеr long pеriods of timе-thаt is, ovеr many gеnеrations-and undеr thе сontinuеd sеlесtivе influеnсе of thе еnvironmеnt (thе so-сallеd strugglеfor ехistеnсе),a gгoup of organisms would havе еvеntually aссumulatеd many nеw favoraЬlе variations. Thеy would thеn diffеr suffiсiеntly ..originof from thеiг anсеstoгsto соnstitutеа nеW tахonomiс stаtus:thus thе .lfallaсе spесiеs.'' wrotе out а draft of his сomplеtе thеOry in thе now-сlassiс

еssay ..On thе Tеndеnс Т y p . ' ' ( 1 8 5 8 ) ,a n d m a i l аlong with ехtraсts fr( writtеn Ьy Darwin in 1[ thе Linnеan Soсiеty (Lr thе puЬliсati
tuге hаd Ьееn, ltIld сtlnti

lr"rtionof tlrе human spе By еmphasizing that politiсal аnd soсial idес tionary pfoсеss Ьr'rtеssе еvolution,'VЙrllaсеесho Pгominеnt еvсllutionar St. Gеorgе Мivart, аmo to a sсiеntifiсallvrigoro tion that сеrtain aspесts еnt purposivеnеssof m' for ехplanations thаt tr laсе tyрifiеd a пlаljorst of еvolutiorrагyЬiology to Ьuild a сomprеhеns nаturе. .!Иallaсе is onе of thе еvolutionar1' Ьiology pr proсеss intеgratеd so di сontinuе to rеsonatеin с ultimаtеly' signifiсanсеr At thе start of thе twеrr ation sсiеnсеprеsеntdar е v o l u t i o n a r yЬ i o l o g y w i tionary thеory and uorl tion of sсiеnсеand thе Ь

'Wаllасе l prеviollslysееn Ьy Еuropеans. ersеhuman irrhaЬitаntsof thosе aphiс distriЬution of spесiеs lеd ry. Hе proposеd thаt thе spесiеs Iwеrе ovеrwhеlmingly Indian in :rе pгеdominantly of Australian taгythеory and сopious fiеld oЬ_ aratеs thе Indiarr fr
..on thе Теnсlеnсy еssay of Variеtiеs to Dеpart Indеfinitеlyfrom thе original Typ.'' (1858)' arrd mailеd it to D:rгwin in Еnglanсl.A сopy of WаllaсеЪ еssay' along with еxtrасts from an r.rrrpuЬlishеd manr.rsсripton natllr21lsеlесtiоn writtеn Ьy Darwin in 1844, wеrе prеsеntеdtogеthеrat thе historiс mееtingof thе Linnеan Soсiеty (London) on July 1, 1858. This mееting' a yеar Ьеforе thе puЬliсation tlf Г)arwin's Оп thе Оrigiп of ,Spеcics(1859), еnsuгеd that Ьoth \Уallaсе and Dаrwin rесеivеd гесognition аnd ioint prioritv for thеir momеntous асlriеvеmеnt. On his rеturn tсl Еngland in |862 \Иаllaсе spеnt thе rеmаindеr сlf his long lifе еluсidating thе impliсatintlrе sсopе' mесhaIrism,and, ultimatеly, signifiсanсеof еvo[шtionin Ьoth sсiеrrtifiсand сultural domains. At thе start of thе twеnty-firstсеntury' whеn thе advoсatеs of so-сallеd сrеation sсiеnсеprеsеntdаngеrousoЬstaсlеsto ir fullеr undеrstandingof thе rolе еvolutionary Ьiology will аnd mr'rstplay in modеrn soсiеty, Wаllaсе's еvolutionary thеory anс]w,orldviеwprovidе a сogеnt Ьasis for a judiсious intеgratiсln of sсiеl-lсеаrпdthе Ьroirdеrсulturе.

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'Wаtsr-lп аnd Сriсk в|BLIoGRAPHY Thе Alfrеd Russеl\iИallaсеPagе.http://www.wku.еdu/-smithсh/indеx1.htm. Мaintainеd at $иеstеrnKеntuсky Univеrsity,Bowling Grееn,Kеntuсky. Bеrry,A.' ed.2002. IпfiпiteTropics:Ап Аlfred RussеlWаllасeАпthologу,Nеw York: Vеrso' Сamегini,J. R., еd. 20ОZ,Тhе Alfrеd RиssеlWаllасеRеаdеr:А Sеlесtioпof Writiпgs from thе Fiеld. Ba|timorе:Johns Hopkins UnivеrsityPrеss. Daws, G.' аnd М. Fttiita. 1999. Аrсhipеlаgсl:Thе Islаnds t>fIndсlпеsiа,from thе Niпеtеenth-СeпtltrуDisсoueriesof Alfred RussеlWаl!асеto thе Fаtе of Forеsts апd Reefsiп thе Tшеntу.firstСeпturу.Bеrkеlеy:Univеrsityof Сalifornia Prеss. Fiсhman,М. 2004. Аn Еlusiuе Уiсtoriап:Tbе Еuolutiсlnof Аlfrеd RusselWаllасе. Сhiсago:Univеrsityof Сhiсago Prеss. Knapp, S. 1'999.Footstеpsiп thе Forеst:Alfrеd RussеlWаlIасеiп thе Amаzon. London:Nаturаl НistoгyMusеum. Мarсhant,l., ed. [|916| 1975' Аlfred Russеl Wаllасе:Lеttersапd Remiпisсепсеs. Nеw York: Arno Prеss. RaЬy, P. 2ООI.Аlfrеd RussеIWаlllасe:А Lifе' Prinсеton'NJ: PrinсеtonUnivеrsity Prеss. Smith,С. H., еd. 1991' Аlfrеd RusselWаllасе:Ап Аnthologу of His Shortеr Writiпgs.Oхford: Oхford UnivеrsityPrеss. !Иallасе,A. R. 1853. А Nаrrаtiuесlf Trаuelsсlп t|эeАmаzс>lz апd Rio Nеgro. London:Rееvе& Сo. 1855.on thе lаw whiсh has rеgшlatеd thе introduсtionof nеw spесrеs. АппаIsапd Маgаziпе of Nаturаl Historу |6 (2nd sеriеs):184_196. 1858.on thе tеndеnсyof variеtiеsto dерartindеfinitеlyfrom thе originа[ tуpe.Journаlof thе Proсeеdiпgsof tbе LiпneаnSoсiеtу,ZсlologуЗ, no.9: 53_62. |876. Thе GеogrаphiсаlDistributioпсlfAпimаIs.2vols.London: -М.F. Масmillan& Сo.

T h е f i r s tp u Ь l i сr е р r е s е аnd Сriсk 1953.)

Watson,Jamеs (b. 1928)' and Сriсk, Franсis (Т9Т6-2004) .Watson In 1953 thе Amеriсan Jamеs and thе Еnglislrman Fгanсis Сriсk, working at Сambridgе Univеrsity, disсovеrеd thе strrrсturе of thе dеoхyribonuсlеiс aсid (DNA) molесulе, long suspесtеd to be thе сarriеr of thе gеnеtiс infoгmation within thе сеll. Thеy found that it was a pair of long molесulеs, гwinеd around еaсh othеr in a douЬlе hеlix (sееfiguге)'Vеry еxсitingly, thе DNA molесulе сonsists of four diffеrеnt kinds of smallеr moleсulеs:adеninе (A), thyminе (T), guaninе (G)' and сytosinе (C). Thе opposing DNA molе. сulеs arе linkеd togеthеr, with onе of еaсh kind of smallеr molесцlе always spесifiсally pairеd on thе othеr DNA molесulе with anothеr of thе four molесulеs (A with T, and G with С). s7atson and Сriсk immеdiatеly hypothеsizеd that thе ordеr of the smallеr molесulеsсarriеsthе infoгmation of hеrеdity,and so it provеd latеr in thе dесadе whеn thе so-сallеd gеnеtiссodе was сrасkеd. It was found that information fronr thе DNA is usеd to makе thе Ьuilding Ьloсks of thе сеll, as wеll as thе еnzymеsusеd to drivе proсеssеs.Iп 1962Watson, Сriсk, and a Univеrsity of London rеsеarсhеr, Мauriсе Wilkins' iointly rесеivеd thе NoЬеl Prizе for Меdiсinе or Physiology for thеir dеtеrmination of thе struсturе of DNA.

Initially, rеlationslrip vеry tеnsе' with thе for and thе lattеr rеgarding autoЬiographtcal Тhе L guagе). Thе systеmatis provе thаt evoIutionаг standing' and that lrеnс standing aЬout wholе о сonfеrеnсеon thе philor quitе еqual to that of \й4 thе sаmе Ьiolоgv dерaг ..tlrе most unplеаsаr-rthr s o n i s d е t a i l е di n h i s с i : and thе morе traditiona By thе 1960s, howеvс iar tесhniquеsсould thr аtiorr, that wеrе inrp
'\Yаtsoп аnd Сriсk

е d u / - s m i t h с h / i n d еl .xh t m . B o w l i n gG г е е n 'K е n t u с k y . вsеl Wаllасе Апthologу. New rcе Rеаdеr: A Sеlесtioп of Writiпgs 'vеrsity Prеss' Islапds of Iпdсlпеsiа, from thе ssеI WаIIасе to the Fаtе of Forеsts еy: Univеrsity of California Prеss. .Wаllасe. iutioп of Alfrеd Russel вsеI Wаllаcе iп thе Аmаzoп. асе: Lettеrs апd Remiпisсепсеs. nсеton.NJ: Pгinсеton Univеrsity Апthologу of His Shorter e Аmаzoп aпd Rio Negro. introduсtionof nеw spесiеs. .2nd sеriеs):184_196. гt indеfinitеly from thе original э Soсiеtу,Zoologу 3, no. 9: 5з-62. |пimаls. 2 vols. London:

-NT.F. Thе first puЬliс rеprеsеntationof thе now-famous douЬlе hеlix. (From !7atsоn and Сriсk 195З.)

inglishman Franсis Criсk, work. I struсtrrrе of thе dеoxyribonuгo Ье thе сaгriег of thе gеnеtiс it was a pair of long molесulеs, (sееfigurе). Vеry еxсitingly, thе ls of smaller molесules: adеninе (С). Thе opposing DNA molе.ind of smallеr molесulе always [е with anothеr of thе four molСriсk immеdiatеly hypothеsizеd thе information of hеrеdity, and :allеd gеnеtiс сodе was сraсkеd. A is usеd to makе thе Ьuilding to drivе proсеssеs.In 1962Vattrсhеr' Mаuriсе Wilkins, jointly ysiologyfor thеiг dеtегmination

Initially, rеlationshipsЬеtwееnmolесular Ьiologists and еvolutionistswеrе vеry tеnsе' with thе formеr rеgarding thе lattеr as mеrе ..stamp сollесtors'' and thе lattеr rеgarding thе formеr as ..rеduсtionists''and worsе (lfatson's autobiographica| Thе Doublе Heliх [1968l usеs this kind of dеmеaning languagе). Thе systеmatistЕгnst Mayr was onе who turnеd to philosophy to provе that еvolutionary thеorizing has its own spесial prinсiplеs of undеrstanding, and that hеnсе molесular Ьiology сan yiеld little
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Wаtson аnd Сrick insight of Riсhard Lеwontin, fully dеsсribеd in his Gепеtiс Bаsis of Еuolutioпаrу Сhапgе, 1974)' This has сontinuеd to thе pгеsеnt, and еvolutionists havе bееn among thе kееnеst to do gеnеtiс fingеrprinting to dеtеrminе hеrеdity and othеr mattеrs of intеrеst (sее'for instanсе' Daviеs |992 on thе hеdgе sparrows' thе dunnoсks). At thе samе timе molесular Ьiology has givеn risе to onе of thе morе important nеw hypothеsеs aЬout еvolutionary сhangе' namеly, thе Japanеsе hypothеsis that at thе molесular lеvеl muсh vаriation еsсapеsthе forсеs of sеlесtion and so drifts from onе pеak to anothеr. (Thе сhiеf author of thе ..nеutral thеory'' was Мoto Kimura [1983]. lfith good rеason' most Darwin еvolutionists do not find it at all thrеatеning Ьесausе thе proсеssеs oссur аt a lеvеl Ьеlow that at whiсh natural sеlесtion opеratеs. Sее Godfrеy.Smith 2001 for an insightful disсussion of thе rеlationships bеtwееn sеlесtionist and nonsеlесtionist thеoriеs of еvolution.) Although in somе rеspесts this is still a сontrovеrsial idеa, it hаs provеd vеry fruitful whеn it is еmplоyеd in a molесular сloсk, dеtеrmining thе datеs sinсе major еvolutionary еvеnts oссurrеd (sееthе main еssay ..Molесular Еvolution'' Ьy Franсisсo J. Ayala in this volumе). This was partiсularly signifiсаnt in pеrsuading palеoanthropologists (studеnts of human еvolutionary history) that thе human-apе Ьrеak oссurrеd muсh morе rесеntly (aЬout 5 million yеars ago) than thе fossil rесord apparеntly suggеstеd(sееthе main еssay ..Human Еvolution'' Ьy Hеnry М. МсHеnry in this volumе). Most fruitful of all, pеrhaps,has Ьееn thе way in whiсh molесular studiеs havе Ьrought dеvеlopmеnt (еmЬryology) right Ьaсk into thе еvolutionary synthеsis.Thе еvolutionistsof thе 19З0s tеndеd to trеat organisms rathеr likе Ьlaсk Ьoxеs, jumping straight from thе gеnеs (gеnotypеs)to thе physiсal fеaturеs (phеnotypеs).Now, molесular Ьiology is opеning up thе ways in whiсh thе information at thе gеnetiс lеvеl is translatеd into physiсal fеaturеs,and a wholе nеw synthеsisof molесular studiеs and dеvеlopmеntal studiеs has Ьееn сrеatеd,making disсovеriеsquitе undrеamеd of еvеn a сouplе of dесadеs ago. Boostеd Ьy studiеs of thе сomplеtе gеnomеs of diffеrеnt organisms, inсluding humans (е.g.,thе Human Gеnomе Projесt),еvolutionary dеvеlopmеnt, so-сallеd еvo-dеvo' is among thе hottеst arеas of study today and promisеs muсh for thе futurе. .Wе havе сomе full сirсlе. Мolесular Ьiology' whiсh Ьaсk in 1953 sееmеd thе nеmеsis of еvolutionary Ьiology, is today in mаny rеspесts its grеatеst supportеr-Ьoth handmaidеn and guidе to nеw arеas of study and disсovеry. в|BLIoGRAPHY Сarrоll, S. B. 2005. ЕndlеssForms Мost Bеаutifиl:Тhе Nеш Sсiепсеof Еuo Dеuo апd the Маkiпg of the Animаl Kiпgdom.Nеw York: Norton. .!7еathеrЬее. Сarroll,s.B.' J.K. Grеniеr,and S. D. 20О1.From DNА ro Diuеrsitу: Мolесulаr Gепеtiсsапd thе Еuolutioп of Аnimаl Desigп.Oхford: Blaсkwеll. Daviеs,N. B. 1992.Duппoсk Bеhаuiourапd SoсiаlЕuolиtion.oхford: oхford UnivеrsityPrеss. Godfrеy-Smith, P. 2001.Thrееkindsof adaptationism. In S. Н. orzaсk and Е. SoЬеr,eds.,Аdаptаtionismапd Оptimаlitу,335_357.Сambridgе:СamЬridgе UnivеrsityPrеss.

Kimura, M. 1983. Thе Nеt Cambridgе Univеrsity Lеwontin' R. С. 1974. TЬе Сolumbia Univеrsity Р Мayr, Е. 1969. Сommеnta 'Watson, 1968. The Doul .Watson,J. J. D., and F. H. с. Nаturе 171:737. !Иilsоn' Е. o. 1'994.Nаtur,

Wеismann,August.

August lfеismann wаs с ary Ьiologists of thе latе rеmеmЬеrеd today for h distinсtion from thе son thе viеw that aсquirеd сJ сonсеrnеd with thе rеla mеntal proсеssеs.This е day synthеsisof еvoiutto August.Wеismann was aсadеmiсs and artists. Al s i с i a n i n h i s y o u г h ,W е i mеаns to makе a living ing Darwin's Oп the O Haесkеl, soon bесamе Aftеr moving to Frеiburд ology, foсusing primaril; сially of insесts).Sеvеrе his еmpiriсal studiеs for .lfеism During that timе win's idеas' еmphasizing .Wеismann еvolution. wi pangеnеsisаnd any оthе thе Ьasis of rесеnt findir гion in l875 of thеfusio vations of intraсеllular еl his own viеws Ьoth on t morе gеnеral proсеssеsс subсеllular units (inсluс make up thе сhromosom t o е х p I a i nr h е d i f f е r е n t vеlopmеnt as a сonsеqu units during suЬsеquеn tеrial during dеvеlopmе rhаt сontain thе full ссl

Wеismапn l in his Gепetic Bаsis of Еuolиto the prеsеnt' and еvolutionists ngеrprintingto dеtеrminе hеrеd:anсе,Daviеs |992 on thе hеdgе ivеn risе to onе of thе morе img сhangе, namеly, thе Japanеsе Lvariation еsсapеsthе forсеs of Lothеr.(Thе сhiеf author of thе !Иith good rеason' most Darwin Ьесausеthе proсеssеsoссur at a )еratеs.Sее Godfrеy-Smith 2001 ps bеtwееn sеlесtionist and nonL in somе rеspесts this is still a whеn it is еmployеd in a molесrr еvolutionary еvеnts oссurrеd ly Franсisсo J. Ayala in this vol,еrsuading palеoanthropologists t thе human-apе Ьrеak oссurrеd 3o) than thе fossil rесoгd apparrolution'' Ьy Hеnry M. МсHеnry has Ьееn thе way in whiсh mo.mbryology) right Ьaсk into thе hе 1930s tеndеd to trеat organIt from thе gеnеs (gеnotypеs) to есular Ьiology is opеning up thе l lеvеl is translatеd into physiсal ;ular studiеs and dеvеlopmеntal quitе undrеamеd of еvеn a сou: сomplеtе gеnomеs of diffеrеnt an Gеnome Projесt), еvolution1g thе hottеst arеas of study togy, whiсh Ьaсk in 1953 sееmеd ry in many rеspесts its grеatеst ]w arеas of study and disсovеry.

|:Thе Neш Sсiепсеof Еuo Deuo v York: Noгton. . 2001.From DNА lсl Diuеrsitу: mаl Dеsigп.Oхford: Blaсkwеll. аI Еuolutioп.oxford: Oxford nism.In S. H. orzасk and ' 335_357.Сambridgе:СamЬridgе

Kimura, M. 1983. Thе Nеutrаl Thеorу of Мolесulаr Еuolutioп.СamЬridgе: СamЬridgеUnivеrsityPrеss. Lеwontin,R. С. 1974. Тhе Gепеtiс Bаsisof Еuolutioпаrу Сhаnge.Nеw York: СolumbiaUnivеrsityPrеss. Мayr, Е. 1969. Сommеntarу.Jourпаl of thе Historу of Biologу 2, лo' 1.:123_\28. Watson,J. 1968. Tbe Doublе Hellr. Nеw York: SignеtBooks. Watson,J.D., and F. H. с. Criсk. 1953.Molесularstruсturеof nuсlеiсaсids. N а t u r e1 ' 7 1 : 7 З 7 . Wilson' Е. o,1994, Nаturаlist..Washington, DС: IslаndBooks/Shеarwatеr Books. -^4.R.

Wеismann,August Friеdriсh Lеopold (|834_|9|4) August !Иеismann was onе of thе most influеntial zoologists and еvolutionary Ьiologists of thе latе ninеtееnth and еarly twеntiеth сеnturiеs. Не is still rеmеmЬеrеd today fоr his thеory of thе сontinuity of thе gеrmplasm and its distinсtion from thе somatoplasm, as wеll as for his staunсh opposition to .sИеismann thе viеw that aсquirеd сharaсtеrs сan Ье inhеritеd. was еspесially сonсеrnеd with thе rеlatiоnship of еvolutionary, hеrеditary' and dеvеlopmеntal proсеssеs.This еmphasismakеs him also a forеrunnеr of thе prеsеntday synthеsisof еvolutionary dеvеlopmеntalЬiology (еvo-dеvo). August \й/еismannwas Ьorn in 1834 in Frаnkfurt am Main into a family of aсadеmiсs and artists. Alrеady an ardеnt Ьuttеrfly сollесtor and talеntеd mu. siсian in his youth, \й/еismannstudiеd mеdiсinе in Gсittingеn as a praсtiсal mеans to makе a living whilе pursuing his intеrеsts in sсiеnсе. Aftеr rеad.W.eismann, ing Darwin's Оп thе origiп of Spесiеs in 1861, nехt to Еrnst Нaесkеl, soon bесamе onе of Darwin's strongеst advoсatеs in Gеrmany. Aftеr moving to FrеiЬurg in 1863,.Wеismanndеvotеd himsеlf full-timе to zoology, foсusing primarily on сomparative emЬryology and сеll Ьiology (еspесially of insесts).Sеvеrеproblеms with his еyеsight forсеd him to intегrupt his еmpiriсal studiеs for an ехtеndеd pеriod during thе 1860s and 1870s. .sИеismаnn During that timе dеvotеd himsеlf to a thеorеtiсal analysis of Dar. win's idеas' еmphasizing thе rolе of hегеdity and dеvеlopmеntal proсеssеs for .sИеismann еvolution. Was a striсt sеlесtionist: hе rеiесtеd Darwin's idеa of pangеnеsisand any othеr notion of thе inhеritanсе of aсquirеd сharaсtеrs. On thе Ьasis of rесеnt findings in сytology, еspесially Osсаr Неrtwig's oЬsеrvation in 1875 of thе fusion of nuсlеi duгing fеrtilization, and of rеlatеd oЬsеr.VИеismann vations оf intraсеllular еvеnts during сеll division, bеgan to dеvеlop (1885) his own viеws Ьoth on thе сontinuity of thе gеrmplasm and on thе morе gеnеral proсеssеs of dеvеlopmеnt and hеrеdity. Postulating a systеm of suЬсеllular units (inсluding dеtеrminants, ids, and othеr units that would .s7'еismann makе up thе сhromosomеs) as сarriеrs of hеrеdity, also attеmptеd to еxplain thе diffеrеntiation and dеtеrmination of partiсular сеlls during dеvelopmеnt as a сonsеquеnсе of a sеlесtivе distriЬution and aсtivation of thеsе units during suЬsеquеntсеll divisions. Suсh altеrations of thе hеrеditary matеrial during dеvеlopmеnt, howеvеr, rеquirеd that thе gеrmplasm, thosе сеlls that сontаin thе full сomplеmеnt of hеrеditary faсtors. would Ье sеt asidе

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Weldon еarly during dеvеlopmеnt, Ьесausе.Wеismann'sown еxpеrimеnts had dеmonstratеd that somatiс сhangеs arе not passеd on to thе nехt gеnеration. IWеismannspеnt his wholе сarееr as a zoologist at thе Univеrsity of FгеiЬurg. Hе was thе first to hold thе сhair in zoology (from 1874 on) and ovеrsaw thе еxpansion of thе zoologiсal institutе and its faсilitiеs. During his tеnurе FrеiЬurg Ьесamе onе of thе lеading institutions of zoologiсal rеsеarсh. \Vеis. mann also attraсtеd sоmе of thе Ьrightеst studеnts from all ovеr thе world, and many of his pupils latеr hеld prеstigiouspositions.Aftеr rеtiringin 1912, 'Vfеismann prеparеd thе final (third) еdition of his Vortriige йbеr Desсeпdeпzthеoriе (puЬlished in 1913). Hе diеd in 1974, dееply disappointеd Ьy thе .!7orld .$Иar outЬrеak of I. в|вLIoGRAPHY Gaupp, Е. |9\7. August Weismапп,seiп Lebеп uпd sеiп Wеrk. lena..GustavFisсhеr. .W.еismann, ^. \892. Dаs Kеimplаsmа:Еiпe Theoriеdеr Vеrеrbuпg..|еna:Gustav Fisсhеr. 1893. Тhе Gеrm-Plаsm:A Тhеorу сlf Hereditу.Nеw York: Сharlеs Sсribnеr'sSoпs. -М.D.L. 1902. Vortrrjsейbеr Dеsсепdепztheсlrie, Tеnа:GustavFisсhеr.

Wеldon, W. F. R. (1860_Т906) Nи.F. R..W.еldon(hе was known as Rаphaеl.Wеldon to intimatеs and family) was profеssor of сomparativе anatomy and zоology at Univеrsity Сollеgе, London, and thеn latеr Linасrе Profеssor of Zoo|ogу at oxford. His honors inсludеd Ьеing a fеllow of thе Royal Soсiеty and prеsidеnt of thе British Assoсiation for thе Advanсеmеnt of Sсiеnсе. Не was a lеading mеmЬеr оf thе group of еvolutionists known as thе ..Ьiomеtriсians''' who triеd to analrуzе сontinцous variation shapеd Ьy natural selесtion' as opposеd to thosе taking up thе nеw thеoriеs of hеrеdity,thе ..Mеndеlians.''A vigorous сontгovеrsialist, !Иеldon сarriеd on a vitrioliс fеud with his formеr studеnt (and lеading British Меndеlian) lWilliam Batеson. It is thought that thе strain of this fight was a сontriЬutory faсtor to his еаrly dеath. .sИallaсе Сharlеs Darwin and Alfrеd Russеl wеrе not thе first to proposе еvolution as a proсеss or thе еvolution of nеw spесiеs; Darwin сitеd 34 antесеdеnts in thе ..Historiсal Skеtсh'' at thе Ьеginning of oп the origiп of Species. Thе morе original aspесt of thеir сontriЬution was to сhampion nat. .Wеldon ural sеlесtion as thе mесhanism that сausеs еvolution. \Jr. F. R. dеvеlopеd thе most prominеnt rеsеarсh program of thе ninеtееnth сеntury that сharaсtеrizеd thе proсеss of natural sеlесtion. Hе arguеd that suсh studiеs must Ье statistiсal in naturе in that thеy must сharaсtеrizе how traits variеd among individuals within a population, thе ехtеnt to whiсh this trait variation was transmittеd from parеnt to offspring, and thе еxtеnt to whiсh trаit variation influеnсеd survival. Finally, hе showеd that if thеsе thrее сonditions prеvailеd, thе avеragе valuе of a trait in a populаtion would сhangе ovеr timе. Hе сollaЬоratеd with Karl Pеarson, who dеvеlopеd statistiсs for

с h a г a с t е r i z i n gv eг i a t i с within and among gеnе of his prominеnt studу moenаs) found nеar thr mouth Sound. Hе show figurе)wаs wеll dеsсriЬ h a d p г е v i o u s | ys h o w n '. m a n y s p е с i е s .H е a I s l l t h а n i n a d u l t с r а Ь s 'w h narrowеst frontal widtt h a d Ь е е n s е l e с r е dа g a i now сall stаbiliziпg selе t u r е . H е f е | tt h а r t h i s w l еrаgеtrait of а popLrla oссur rapidly in rеspon only Ье sееn if onе wе s u с h a с h а n g ео с с t t r г е thе frontal Ьrеadth of tl isolatеd from thе oсеaп finе сlay sеdimеnt that r Hе showеd еxpеrimеn l i k е I yt o s u r v i v ее х p o s u

Thе сraЬ whosе statistiс T h е с r u с i а lm е a s u г е m е ! 7 е l d o n1 8 9 5 . )

Weldoп own ехpеrimеntshаd dеmonto thе nехt gеnеration. st at thе Univеrsity of FreiЬurg. :om|874 on) and ovеrsaw thе i faсilitiеs. During his tеnurе 'W.еiss of zoologiсal rеsеaгсh' cеnts from all ovеr tlrе world, lsitions'Aftеr rеtiring in 1'9-!'2, Ьts Vortriige йbеr Dеsсепdeп4, dееply disappоintеd Ьy thе

I sеiпWеrk.Jеna:GustavFisсhеr. е dеr Уеrеrbипg. Jеna:Gustаv y'iry'Nеw York: СЬarlеs :r:GustаvFisсlrеr.

-М.D.L.

/еldonto intimatеs and family) roolоgy аt Univеrsity Cоllеgе, ,oology at oхfoгd. Нis honors nd prеsidеntof thе British As: Was a lеading mеmЬеr of thе riсians,'' who triеd to analyzе on' as oPPosеd to thosе taking rns.''A vigorous сontrovеrsialis formеr studеnt (and lеading Lghtthat thе strain of this fight , Wеге not thе first to proposе v spесiеs;Darwin сitеd 34 anеginning of Оn the origin of г i Ь u t i о nW a s t o с h а m p i o n n a t volution. \r. F. R. WЪldon dеr of thе ninеtееnth сеntury that .. Не arguеd that suсh studiеs сhаraсtеrizеhow tгaits variеd хtсnt to whiсh this trаit vаria;, and thе еxtеnt to whiсh trait wеd that if thеsе thrее сondi. in a population would сhangе r' who dеvеlopеd statistiсs for

сharaсtеrizing vari:rtion within populations and hсlw this variation сhangеd within and among gеnеrations(a nraioг ссlntriЬr-rtion was Pеarson 1894). onе of his pгominеrrtstudy systеmsw:ls thе shеll morphology of сraЬs (Саrciпus tпoeпаs)found nеar thе laЬoratory of thе Marinе Biologiсal Statiorron Plymouth Sound. Hе showеd that thе Pattеrn of variation of frontаl Ьгеadth (sее figurе)wаs wеll dеsсriЬеdЬy a norrr-lаldistriЬution, whiсh, as Franсis Galton had prеvior-rsly shown, сharaсtеrizеsthе pаttеrn of vаriation in.manу traits in many spесiеs. Не also showеd thаt this distriЬr"rtionwas widеr in juvеnilе thаn in adult сraЬs, whiсh suggеstеdthat individuills that had thе widеst and narrowеst frontal widths wеrе lеss likеly to survivе to maturity, or that thеy had bееn sеlесtеdаgainst. Hе аrgr"lеdthat this forrrr of sеlесtion,whiсh wе now сall stаbilizing sеlесtioп, woulс] Ье thе most сomlllon proсеss sееn in natuге. Hе fеlt that tl.riswas truе Ьесausеsеlесtiоr-rthzrtсausеd сhаngеs in thе avегagе trait of a pсlpulation' whiсh Wе now сalr|clirесtirlпаl sеlесtioп, would oссur rаpidly in rеsponsеto a сhangе in thе еnvir
Thе сraЬ whosе sti.ttistiсsRаphaеl \Wс|donссlllесtеd апсl Kаrl Pеarson ana|уzed. Thе сrr"rсiаlmеasuгеlтlеIltwas thе ..froпtаl Ьrеadth.'' frсlrn A to A'. (Fron.t !Иеldсln 189.5.)

911

912

Wеldoп showеd, that a narrowеr frontal Ьrеadth would prеvеnt thе aссumulation of .!Иеldon sеdimеnt in thе gill сhamЬеrs. and Pеarson сomЬinеd thеir еmpiriсal and statistiсаl skills to сrеatе biomеtry, or thе statistiсal study of vaгiation and еvolцtion in natural populations. Мany othеr invеstigatorsаdoptеd thеir approaсh. Our сurrеnt undегstandingof еvolution Ьy natural sеlесtionindiсatеs that all of !7еldon's gеnеral сonсlusions wеrе сorrесt. Furthеrrnorе, his gеnеral approaсh to thе study of naturаl selесtionis similar to that of modеrn invеstigators. Givеn his pionееring aссomplishmеnts' onе might ехpесt that \Иеldon's namе would appеar prominеntly in еvеry gеnеral Ьiology tеxtЬook or gеnеral trеatmеnt of natural sеlесtion; howеvеr, hе is all but invisiЬlе in modеrn litеraturе' ехсеРt in somе historiсal rеviеws (whеrе his impoгtаnсе is inсrеasingly bеing rесognizеd-sее еspесiаlly Rusе 1996). Furthеrmorе, if wе wеrе to еvaluatе whеrе thе modеrn approaсh to thе study of natural sеlесtion сamе from, thе trail would lеad Ьaсk to thе 1940s, thеn diffusе into .What stray tгaсks that go Ьaсk only I0 or 2О yеaгs еarliеr. happеnеd? oЬviously his еarly dеath was а signifiсant сontгiЬuting faсtor, sinсе it lеft thе fiеld opеn to Batеson and thе Mеndеlians. Howеvеr, thеrе wеrе sсiеntifiс .$7еldon's faсtors сontriЬuting to fall from sight. Thе study оf еvolution Ьеtwееn 1880 and 1'920 was dominatеd Ьy dеЬatеsovеr thе mесhanism of in. hеritanсе, sinсе еvolution dеmands that tгaits that сhаraсtеrizе survivors Ье .lfеldon's trаnsmittеd to thе nехt gеnеration. It wаs misfortunе to сhampion a mесhanism of inhеritanсе that wаs wrong. Hе, Pеarson, and thеir fеllow Ьiomеtriсians arguеd that hеritaЬlе variation was сontinuous' as sееn in a statistiсal distribution of traits iп а natr.rralpopulation. Thеy аlso failеd to distinguish Ьеtwееn variation that was сausеd Ьy gеnеs vеrsus variation сausеd Ьy thе еnvironmеnt and, furthеr, oftеn sееmеd to imply that traits in parеnts that werе сausеd Ьy thе еnvironmеnt сould Ье transmittеd to offspтing. Finally, thеy arguеd that thе transmission of traits from fathеr and mothеr to offspring was likе thе mixing of paint. If thе fathеr was a diffеrеnt сolor from thе mothеr, thеn thеsе diffеrеnсеs would Ье inеxtгiсaЬly Ьlеndеd togеthеr in thе offspring. Thе rеdisсovеry of Mеndеl's laws of inhеritanсе instеad showеd that inhеritanсе is partiсulatе, mеaning that traits arе faithfully transmittеd fronr parеnt to offspring and thе traits from еaсh parеnt rеmain disсrеtе, so thеy сan еmеrgе unсhangеd in futurе gеnеrations.!Иеldon's rеmaгkaЬlе aссomplishmеnts in thе study of natural selесtion thus diеd as innoсеnt Ьystandеrs of his loss in thе Ьattlе ovеr inhеritanсе. Pеarson was morе fortunatе sinсе somе of his statistiсal innovations, suсh as thе Pеarson produсt-momеnt сorrеlation' arе still with us. The modеrn approaсh to thе study of natцral sеlесtion was rеboгn' bеgin. ning in thе 1930s, aftеr thе diffеrеnt approaсhеs to thе study of inhеritanсе wеrе геsolvеd. BIBLIOGRAPHY Darwin, С. |959' Тhе Оrigin of Spесiеsbу СhаrlеsDаnuin: A VаriorltmTехt. М. Pесkhаm,еd. Philаdеlphia; Univеrsityof Pеnnsylvania Pгеss.

P е а r s о n ,K . I 8 9 4 . С o n t r Рhilosсlphiсаl Trапs .Waltеr -.\\906. Fr: Provinе, !и. B. l 97|. Th Univеrsity of Сhiсaд Rusе' М. |996. Мoпаd t Cambгidgе, МA: Hr !Иеldon, !и. F. R. 1890. I. Сrаngоn vrrlgaris l 8 9 2 . С е r t а i nс t Roуаl Soсiеtу сlf Lo, l893. on сеrтa thе Roуаl Soсiеt1,o l 8 9 5 . А t t е m p tt t C а r с i n u s m o е n а sW Roуаl Soсiеtу o[ Lol 18 9 8 . P r е s i d е n Assoсiаtion. Тr.lnsа Lorrdon:John Murгl

Whеwеll,William

William lil/hеwеll (pro and undеrstandino gf Britain. Although Ьеs \ W h е w е l l .w s r i г i n g sr а n sсiеnсеsand Ьеvond-r omy' gеology. thеo|o tional lаw, and агсhit сoining nеw tеrms, it v Н i s t е г m i n o l o g i с ailn n Ьy him on thе sсiеnсе. t i o n s i n с l u d i n gp r е s i d Sсiеnсе,fеIlow of thе F longtimе masгеr of Tr Trinity Сol1еgе, Whеw (Dor-rgla1 s 881; Garla еvolutionary idеas all playеrs in thе story. $ w o u l d b е а p p e l l е dа t t Ье sсlmеwhat сomplaс. s i g n i f i с а n r i,s а с o n u n d his God' No douЬt !(h. dесision. Whеwеll is signifiсaп h е е p i t o m i z е dt h е v i s i o gumеnг from Dеsign. (

graduatе days ar СаmЬ

Whеu,,ell 91З d prеvеnt thе aссumulation of rson сomЬinеd thеir empiriсal ] s t a t i s t i с asl t u d у o f v a r i a t i o n lrеrinvеstigators adoptеd thеir tion Ьy natural sеlесtion indi^/еrесorrесt. Furthеrmorе, his on is similar to that of modеrn .!?еldon's э might ехpесt that еral Ьiology tехtЬook or gеnhе is all Ьut invisiЬlе in mod: w s ( w h е r еh i s i m p o г t а n с е i s Rusе 1996). Furthеrmorе, if rсh to thе study of natural sеo t h е l 9 4 0 s ,t h е n d i f f u s е i n t o еarliеr. !Иhat happеnеd? oЬiЬuting faсtor, sinсе it lеft thе [owеvеr' thеrе wеrе sсiеntifiс rt. Thе study of еvolution Ьеtеs ovеr thе mесhanism of inthat сharaсtеrizеsurvivors Ье /еldon's misfortunе to сhamrong. Hе, Pеarson, and thеir .ariation was сontinuous' as ratural population. Thеy also was сausеd Ьy gеnеs vеrsus rthеr' oftеn seеmеd to imply еnvironmеnt сould Ье transhе transmission of traits from niхing of paint. If thе fathеr hеsе diffеrеnсеswould Ье inThе rеdisсovеry of ]Vlеndеl's i t а n с еi s p а г t i с u I a t е m ' еaning : n t t o o f f s p г i n gа n d t h е t r a i t s t еmеrgе unсhangеd in futurе mеnts in thе study of natural his loss in thе Ьattlеovеr in' o m е o f h i s s t a t i s t i с а li n n o v a эoгrеlation. arе still with us. sеlесtion was rеЬorn' bеginl е st o t h е s t u d y o f i n h е r i t a n с е

Dаrшiп: А Vаriorum Tехt. nnsylvaniаPrеss.

Pеarson, K. 1894. Сontributions to thе mathеmatiсal thеory of еvoiution. Philosophicаl Trапsасtions А 1 85: 7|-1ю. 1906. \X/аltеrFrank Raphаеl Wеldon: 1860_1906. Biomеtrika 5: 1_51. Provinе, w' B. 197|. Тhе origiпs of Тheorеticаl Populаtion cепеtics. Chiсago: Univеrsity of Сhiсago Prеss. Rusе, NI. 1996. Мoпаd to Мап: Thе Сoпсеpt of Progress in Еuolutioпаrу Biologу. Сambridgе, MA: Harvard Univеrsity Prеss. .!(i.еldon, W. F. R. 1890. Thе vaгiations oссurring in сеrtain dесapod сrustaсеa. I. Crangon vulgаris. Proсееdiпgs of thе Roуаl Soсietу of Loпdoп 47: 445453. 1892. Cеrtain сorrеiаtеd variations in Сrangon vulgaris. Proсеediпgs of the Roуаl Soсietу of Loпdoп 5I:2_21. 189З. on сеrtain сorrеlatеd variations ln Саrсiпus moеnаs. Proсeedings of thе Roуаl Sociеtу of Loпdoп 54 З18_З29. 1895. Attеmpt to mеasurе thе dеathrаtе duе to thе sеlесtivе dеstruсtion of Сarсinus moеnas with rеspесt to a partiсular dimеnsion. Proceеdiпgs of thе Roуаl Soсietу of Loпdoп 57:36О-З79. 1898. Prеsidеntialaddrеssto thе Zoologiсal Sесtion of thе British Assoсiation. Trаnsасtioпs of thе British Assсlсiаtioп (Bristol), 887_902. London: Jоhn Мurray D.N.R.

.Whеwеll, William (1794_t866) \William \й/hеwеll (pronounсеd Hulе) was a major figurе in thе dеvеlopmеnt and undеrstanding of sсiеnсе in thе first half of thе ninеtееnth сеntury in Britain. Although Ьеst known as a historian and philosophеr of sсiеnсе, .!7hеwеll,s writings rangеd Ьroadly ovеr a hugе numЬеr of othеr fiеlds, in thе sсiеnсеs and Ьеyond-mесhaniсs, сrystalography' minеralogy, politiсal eсonomy, gеology, thеology, еduсational rеform, moral philosophy, intеrnаtional law, аnd аrсhitесturе' to namе Ьut somе (Rusе 1991). Мuсh givеn to сoining nеw tеrms' it was NИhеwеll who invеntеd thе Еnglish word sciепtist' His tеrminologiсal innovations arе еmЬlеmatiс of thе grеat influenсе ехеrtеd Ьy him on thе sсiеnсе of thе agе, through his writings and through his positions inсluding prеsidеnt of thе British Assoсiation for thе Advanсеmеnt of Sсiеnсе, fеllow of thе Royal Soсiеty' prеsidеnt of thе Gеologiсal Soсiеty, and longtimе mastеr of Trinity Сollеgе, СamЬridgе. As rеquirеd of a fеllow of Trinity Сollеgе, !Иhеwеll was an ordainеd ministеr in thе Angliсan Churсh (Douglаs 1881; Garland 1980; Todhuntеr 1876). Adamantly opposеd to еvolutionary idеas all of his lifе, !Иhеwеll was nеvеrthеless onе of thе kеy .Whеthеr, playеrs in thе story. looking Ьaсk a сеntury and a half lаtеr, hе would Ье appallеd аt thе rolе hе playеd inadvеrtеntly, or whеthеr hе would Ье sоmеwhat сomplaсеntly satisfiеd that his idеas and influеnсе wеrе truly signifiсant' is a сonundrum that is lеft for thе rеadеr-and for Whеwеll and his God. No douЬt \Х/hеwеllwould happily havе hеlpеd God to makе thе right dесision. .sИhеwеll is signifiсant to thе story of еvolution in two diffеrеnt ways. First, hе еpitomizеd thе vision of thе organiс world that was prediсatеd on thе Argumеnt from Dеsign. Сharlеs Darwin, who knеw Whеwеll from his undеrgraduatе days at СamЬгidgе and who was muсh in lй/hеwеll's сompany aftеr

914

Wheшеll the Beаgle voyagе (in othеr words, just whеn hе was Ьесonringan еvolutionist and working towаrd natural sе[есtion),rесognizеdrlrаt hе nееdеdto spеak This in mirjor part was thе airn of to this and offеr a full с
.!Иhеwеll

wаs quitе сеr q u е s t i o nq u i r е t l u t s i d е own аnima1 and vеgеtа tion in whiсh thеy wеr w е i n q u i r е w h е n с еt h е tеry of сrеation i5 not nothing, Ьut shе points By thе 1 850s, unfort сoming аpart. By this t г h е с o m p a r a t i v еа n a t o ing to rеwtlrkhis гhin с o u l d Ь е s е е nа s m o d i t еxistеd in thе Divinе М сhristеnеd ..homologiе m а n s t o h o r s е s 'f г o l n , ways, Ьut, aссording t< q u е n с е o f v a r i а r i o n so I o u r a p p а r е n rp u r p o s е .: all сrеation was dеsign gеnеral arсhеtypеs. \Vh t h a t i r w е а k е n е dt h е a l tгovеrsialwork аppеaг of Worlds' \Whеwеllеv kind of arсhеtyре-Ьa univеrsе and not just h thе hеavеnly work'' (p to thе idеa that dеsign1 t i o n i s i m p o s s i Ь l е ,h е suсh strong еvidеnсе < any solution suggеstin thosеwho сIeiIrthatt} еnсing at this point wеr l u t i o n a r y t h o u g h tа s i s

2001,200З).

Darwin not only knе kеy works vеry сlrгеfu .Whеwеll's еnсе to Brid' DarwinЪ nonsupеrnatu not only to еarliеr natu .sИhеwеll (sее Rusе 20С w r i t i n g si n D a r w i n ' sn o also ехtеnsivе nrargina Whеwеll (Di Grеgorio: с u s s i o no t К а n r ' s ( t 7 9 thinking in Ьiology, D; l o o k a t a n i m a l s .o n m 1

'\Yheшеll lе Was Ьесomingan еvo]ution_ gnizеdthat hе nееdеdto spеak in major L]аrtwas thе aim of r m i g h tn o t h a v е Ь е е n a p p r е с i tеwеll'sphilosophiсal thinking J a major mеthodologiсal tool 'hroughnaturаl sеlесtion. е sеriеsof ..BridgеwatеrTrеalеwatеr in ordеr to show how : l l i g е n td е s i g n o f t h е u n i v е r s е d Gеnerаl Phуsics Сoпsidеred Vhеwеll arguеd that thе lawful tегеmust Ье а dеsignеr_сrеator Ьusinеssto slrolv thаt thе laws rn, t|1atis, Ьy thе naturе of thе uantitiеsand propеrtiеs whiсh iсе whiсh is irssignеdto thеm; rr.rdgoodrrеss,in thе powеr Ьy )aгwin rathеr сhееkily usеd a Lgеof thе Оrigiп: ..But with rеs t tf n r а s r h i s - r v е с а n p е г с e i v е lаtеd intеrpositions of Divinе 'y thе еstaЬlishmеntof gеnеral r rnadе otiosе if not сontradiс; to ехplain origins. God did it пrply сould not hаvе appеarеd nеs through еvеn morе stгongly tbе [пdtlсtiь,еSciеnсеs (1837). p l a n е t st o o r g a n i s m s 'a г g u i n g rгy to makе rеfеrеnсе to thе еnd us followеd Iпrmanuеl Kant in ' (Gеrman idеas wеrе vегy pop1 morе powеrful Was thе сasе tdomnеss.Thе organiс world is j lаw. rk Vеstigеs of the Nаtctrаl HisrеspondеdЬy puЬlishing Indii846), a сompilation of ехtraсts f dеsignin thе nаtural world. In еll of suсh nаturalistiс hypothе. namе. Notе, howеvеr, that for al thеology tlrat sеt thе Ьarriеrs of Gеnеsis. Also notе that al:o Ье vеry nruсh a forеrunnеr of Dеsign Thеorists' unlikе thеm

Whеwеll was quitе сеrtain that an appеal to a dеsigning gоd put thе origins qцеstion quitе outsidе thе rеаlm of sсiеl-lсе.Fossil organisms ..wеrе,likе our own animai anсl vеgеtaЬlесOntеmporariеs,profotrndiy adaptеd to thе сondition in whiсh thсy wеrе plaсеd, wе havе amplе rеason to Ьеliеvе;Ьut whеn wе inquirе whеnсе thеy сamе into this our world' gеology is silеnt. Thе mystеry of сrеation is not within thе rаngе of hеr lеgitimatе tеrritory; shе says nothing, Ьut shе pоints upwаrds'' (\Х/lrеwеll1837, З: 588). By the 1850s, unfortunatеly' somе pirrts of !7hеwеll's сarеful systеm Wеrе сoming apart. By this timе' undеr prеssurеfrom thе thеorizing of his friеnd, thе сoпrparativеanatomist Riсhard owеn (1848, 1849), \fhеwеll was having to rеwork his thinking. owеn argr.rеdthat individual vеrtеbratеanimals сould bе sееn as modifiеd instantiations of pattеrns or arсhеtypе forms that еxistеd in thе Divinе Мind. This viеw allowеd Owеn to ехplain what hе had сhristenеd ..homologiеs''-thе similаritiеs of vеrtеbrаtе struсturеs from humans to horsеs, from molеs to mamoths. Thе parts wеrе usеd in diffеrеnt ways, Ьut, aссording to owеn, thеy wеrе unitеd Ьy virtuе of Ьеing a сonsеquеnсе of vаriаtions on thе vеrtеЬratеarсhеtypе.Similarly, struсtцrеswithout apparеnt purposе' suсh аs malе nipplеs, did not сontгadiсt thе сlain-rthat all сrеation was dеsignеd;rathеr, thеy wеrе thе rеsult of thе appliсation of gеnеral arсhеtypеs. Whеwеll aссеptеd this kind of rеasoning' dеspitе thе faсt that it wеakеnеd tlrе appеal to univеrsal utilitarian dеsign. Indееd, in a сontrovегsialwork appеaring supposеdlyаnonymotrslyin 185З, Оf the Plurаlitу of \X/orlds,\Whеwеll еvеn ехtеndеd Owеn-typе thinking, suggеsting that this kind of arсhеtypе-Ьasеd pattеrning is somеthing that holds throughout thе univеrsе and not iust hеrе on еarth: ..Ordеr is thе first and univеrsal Lаw of thе hеavеnly work'' (p. 2aз). But, although \й/hеwеllWas still holding firm to thе idеa that design prесludеs natural сausеs for origins and hеnсе еvolution is impossiЬlе, hе was dramatiсally wеakеning thе сlaim that thеrе is suсh strong еvidеnсе of dirесt dеsign tlrroughorrt tlrе organiс world tЬаt any solution suggеsting nzrtural сausеs is almost сontradiсtory. Thеrе arе thosе who сlaim that thе diffiсultiеs that somеonе likе Whеwеll was еxpеriеnсing at this point wеrе as important faсtors in the еvеntualtriumph of еvolutionагy thought as is thе positivе сasе madе Ьy thе еvolutionists (sеeRusе

200:1,200з).

Dаrwin not only knеw and talkеd to lй/hеwеll, hе also rеad sеvеral of thе kеy works vеry сarеfully. Darwin's privatе еvolution notеЬooks makе rеfеrеl1се to \il/hеwеll's Bridgеwatеr Trеatisе and tо the Historу, sug8еsting that Darwin's nonsupеrnatural ехplanation of adaptation was framеd as а rеsponsе' not oпly to еarliеr natural tlrеologianslikе William Palеy (1802), Ьut also to lfhеwеll (sее Rusе 2003). Thеrе arе aЬout twеnty rеfеrеnсеsto !Иhеwеll's writings in Darwin's notеЬooks (for dеtails,sее Barrеtt et a|, |987). Thеrе aге also ехtеnsivе nrarginalia in thе Historу, gеnеrally not сomplеmеntary to Whеwеll (Di Grеgorio and Gill 1990). For instanсе,against a favoraЬlе disсussion of Kаnt's (|790) сlairrr that tеlеology is а nесеssаryсomponеnt of thinking in biology, Darwin wrotе ..аll this rеasoning is vitiаtеd; whеn wе look at animals, on my viеw'' (!(hеwеll 1837, 3:470).

91.'

916

Wheluеll .!fhеwеll, For all of his opposition to Darwin agrееd that thе dеsignlikе na. (In turе of thе world nееds ехplaining. this' thеy would unitе in arguing against somеonе likе thе latе Stеphеn Jay Gould, who thought that dеsignlikе еffесts arе ovеrvaluеd. Sее Gould and Lеwontin 1979.\ As signifiсantly, in сonstruсting his altеrnativе ехplanation, dеspitе his opposition to thе thеology, Darwin .$Иhеwеll's philosophy of sсiеnсе' was influеnсеd Ьy а vеry important аspесt of namеly, his notion of сonsiliеnсе (Rusе |975,1979). In his Philosophу of thе .!Иhеwеll Iпduсtiue Sсieпсes (1840) еxplainеd that what rеally сounts in sсiеnсе, what геally сonvinсеs you that you havе thе truth-that you havе what Nеwton had сallеd a uеrа cаusа-\s whеn diffеrеnt аrеаs of inquiry сomе togеthеr undеr thе samе hypothеsis. ..Aссordingly thе сasеs in whiсh induсtions from сlassеs of faсts altogеthеr diffеrеnt havе thus iиmpеd tсlgetber' Ьеlong only to thе Ьеst еstaЬlishеdthеoriеs whiсh thе history of sсiеnсе сontains. And as I shall havе oссasion to геfеr to this pесuliar fеaturе in thеir еvidеnсе,I will takе thе liЬеrty of dеsсriЬing it Ьy a partiсular phrasе; аnd will tеrm it tЬe Ссlпsilienceof Iпduсtioпs,,(2:2З0|. (SееKavalovski 1974 for а gеnеraldisсussion .Whеwеll's .!ИhеwеllЪ viеws on сausation. Sее also Snydеr 2О06 for dеtails of of latеr dеЬatеs aЬout сausation, еspесially that with John Stuart Mill.) Thе сon. .W.hеwеll was that of Nеwton, who Ьrought togеthеr silеnсе par ехсеllеnсе for undеr onе law-that of gravitational attraсtion-thе faсts of satеllitе motion' of planetary motion, and of tеrrеstrial moving Ьodiеs. In Nеwton's tеrminology (adoptеd Ьy Whеwеll), thе invеrsе.squarе attraсtivе forсе was a uеrа сс||,|sсI' a gеnuinеly ехisting aсtivе forсе in naturе. Although Darwin rеad thе Historу vеry сarеfully (еvеn twiсе), it is improЬaЬlе that hе rеad thе Philosophу. But' apart from thе pеrsonal сontaсt .lfhеwеll with in thе yеars immеdiatеly suссееding thе Вeаgle voyagе' Dar' win knеw all aЬout thе idеa of сonsiliеnсе from a vеry dеtailеd rеviеw of .!Иhеwеll's idеas Ьy thе philosophеr and astronomеr John F. !И. Hеrsсhеl (1841). It is thеrеforе not surprising that, as rеquirеd Ьy.lfhеwеll's сritеrion of сonsiliеnсе, Darwin's thеory of еvolution Ьy natural sеlесtion ехplains not just many faсts Ьut many diffеrеnt kinds of faсts: fасts of instinсt, gеology and palеontology' ЬiogеographiсdistriЬutions' systеmatiсs'соmpаrativе anatomy' and еmЬryology. Мorеovеr' Darwin's thеory providеs thе сausal unifiсation of сonsiliеnсе Ьy showing that all thеsе diffеrеnt kinds of phеnomеna sharе a сommon сausе' namеly, thе altеratiсlnof original оrganisms Ьy gradual modifiсation through thе mесhanism of natural sеlесtion. Ехpесtеdly, thеrеforе, having donе what his mеntors had dеmandеd, Darwin madе ехpliсit his bеliеf that a сonsiliеnсе offеrs justifiсation еnough. Faсеd with ..I сannot Ьесritiсism, in thе sесond еdition of the Оrigin (1860) hе addеd: it mе liеvе that a falsе thеory would ехplain' as sееms to that thе thеory of natural sеlесtion doеs ехplain, thе sеvеral largе сlassеs of faсts abovе spесifiеd', (Darwtn 1'959,748). Thеn, in thе siхth еdition (7872), hе addеd fur..It has reсently Ьееn oЬjесtеdthat this is an unsafе mеthod of arguing; thеr: Ьut it is a mеthod usеd in iudging of thе сommon еvеnts of lifе, and has oftеn bееn цsеd Ьy thе grеatеst nаtural philosophеrs. Thе undulatory thеory of light has thus Ьееn arrivеd at; and thе Ьеliеf in thе rеvolution of thе еarth on

its own axis was until 1959,748). As Darwin ехplaint BunЬury:

With rеspесt tо Nat fair in Philosophy t nomеna it сomеs in tory thеory of thе l not rесognisеd)is nс Light. Natural sеlес thеtiсal, in as muсh sее how it сan fail tt

Whеn thе Оrigiп a1 all of his old tеaсhеrs My dеar М'Darwir

I havе to thank you You will еasily Ьеliе you will not Ье surр сonvеrt to your doс what you havе writ sеlесtion of thе grou timе for. I must thr kindnеss

Ьеliеvе mе I Yours v С. Darwin Еsq.

(Lеttеr of Januarу 2 .$Иhеwеl PrеdiсtaЬly' nеw еdition of thе Bl (1'864), сontinuing his namе' hе сontinuеd tс Sсienсes, tЬ'at,,specie from onе to anothеr с an anесdotе of Thomс fusеd to allow thе Orz; Whеwеll's сontinuе sсriЬеd as a rеsult of h dеrstand thе mеaning friеnd, thе physiсist Jа

I havе mysеlf takеn Ьut I will not сonсс point has somеwhat сlеar dеfinitе linе, w

Darwin аgrееd that thе dеsigrrlikе nаis, thеy would unitе in arguing against l, who thought that dеsignlikе еffесts t | 9 7 9 ' )A s s i g n i f i с a n t l yi .n с o n s t г u с t is opposition to thе thеology, Darwin ;t of \Иhеwеll'sphilosophy of sсiеnсе, |975' \979). InЬis Philosophу of tbe lairrеdthat what rеally сounts in sсir havе thе rurh-that you havе what зn diffеrеnгаrеаs of inquiry сon.]еtolrdingly thе саsеs in whiсh induсtions rt havе tЬus jиmpеd togethеr, Ьеlong :h thе histoгy of sсiеnсесontains. And есuliar fеaturеin thеir еvidеnсе' I will сular phrasе;and will tеrrn it the Сoпvalovski 1974 for a gеnеral disсцssiоn э Snydеr 2006 for dеtails of WhеwеllЪ that with John Stuart Мill.) Thе соnlrаt of Nеwton, who Ьrought togеthеr :rасtion-thе faсts of satеllitе motion, noving Ьodiеs. In Nеwton's tеrminolluarе attraсtivс forсе was a uerа саusс|' vеry сarеftrlly (еvеn twiсе), it is imBut' apart frorn tl.rеpеrsonal сontaсt / suссееding tЬe Bеаglе voyаgе' Dariеnсе from a vеIу dеtailеd rеviеw of nd astronomеr Jolrn F. W. Hеrsсhеl ]t' as rеquirеd Ьy !7hеwеll's сritеrion llution Ьy natrrral sеlесtion ехplains kinds of faсts: faсts of instinсt, gеol. s r rЬi u t i o n s ,s y s t е l n a t i с sс.o m p а r a t i v е Darwin's thеory providеs tlrе сausal :hat all thеsе diffеrеnt kinds of phе', thе altеration of originаl organisnrs .сhanismof nаtural sеlесtion.ЕхpесtLеntorshad dеmandеd.Darwin madе [еrsjustifiсationеnough. Faсеd with lriciп (|860) hе addеd: ..I сannot Ье. as it sееms to mе that thе thеory of ral largе сlassеsof faсts aЬovе spесi: sixth еdition (1872)' hе addеd furthis is an unsаfе nlеthod of arguing; сommon еvеnts of lifе, аnd has oftеn csоphегs.Thе undulatory thеory of еliеf in thе rеvolution of thе еarth on

its own aхis was until latеly supportеd Ьy hardly any dirесt.u,d.n..,, ::::" t959,748). As Darwin еxplainеd in a lеttеr of FеЬruary 9, |860, to Ьotanist С. F' I. B u nЬ u г y : With rеspесtto Nat. Sеlесtionnot Ьеing a,,Уera сausa''; it sееmsto mе fair in Philosophy to invеnt апу hуpothesis & if it ехplains nrany phеnomеna it сomеs in timе to Ье admittеd аs rеal. In your sеnsеthе undulatory thеory o{ tЬe hуpothеtiсаl еtlrеr (thе undulations thеmsеlvеs Ьеing not rесognised)is nоt a vеra сallsа in aссountiпg for all thе phеnomеna of Light. Naturаl sеlесtion sееms to mе in so far in itsеlf not Ье quitе hypo. thеtiсal, in as muсh if thеrе Ье variaЬility & a strugglеfor lifе' I сannot sее how it сan fail to сomе into play to somе ехtent. (Darwin 7993' 76) .Whеn thе Оrigin appеarеd, Darwin sеnt a сopy to .!Иl-rеwеll,as hе did to all of his old tеасhегs.Vhеwеll rеspondеd with a politе notе: Мy dеar М. Darwin I havе to thank you for а сopy of your Ьook on thе ..origin of Spесiеs.'' You will еasily Ьеliеvеthat it has intеrеstеdmе vеry muсh, and proЬaЬly you will not Ье surprizеd to Ье told that I сannot' yеt at lеast, Ьесomea сonvеrt to your doсtrinеs. But thеrе is so muсh of thought and of faсt in what you havе wгittеn thаt it is not to Ье сontradiсtеd without саrеful sеlесtionof thе ground and mаnnег of thе dissеnt,whiсh I havе not now timе for. I must thеrеforе сontеnt mysеlf with thаnking you foг your kindnеss Ьеliеvе mе | Yours vегy tгulУ | W \Whеwell С. Darwin Еsq. ( L е t t е ro f J а n u a r y 2 , 7 8 6 0 , i n D а r w i n | 9 9 З . 6 ) Prеdiсtably' \й7hеwеlldid not еmЬraсе еvolutionary thеory. In a prеfaсе to a nеw еdition оf the Bridgеwatеr Trеatisе, Аstroпomу апd Geпerаl Phуsiсs (1864), сontinцing his tradition of not rnеntioningvilе еvolutionаrytraсts by nаmе, hе сontinuеd to assеrt' аs hе had writtеn in Historу of thе Iпductiuе Sciепcеs, tЬ,at,.spесieshаuе а rеаl eхistеnсe iп rlаtLrrе,and а trаnsmutаtion from onе to аnothег doеs not еxist'' (.!Иhеwеll1837, З:576). Aссoгding to an anесdotе of Thomas Hеnry Huхlеy, Whеwеll as mastеr of his сollеgе rеfusеd to аllow thе Оrigiп on thе liЬrary shеlvеs! \ffhеwеll's сontinuеd rеluсtanсе to aссеpt еvolutionary idеas is oftеn dеsсriЬеd as a rеsult of his thеologiсal prеjudiсеs.This is truе, Ьut onе must undеrstand thе mеaning and сontехt of Whеwеll's thеology. In a lеttеr to his friеnd' thе physiсistJаmеs David ForЬеs, .!7hеwеllwrotе in 1864: I havе mysеlf takеn no sharе in thе disсussionson thе antiquity of man; but I will not сonсеal 1rom you that thе сoursе of spесulation on this point has somеwhat trouЬlеd mе. I сannot sее without somе rеgrеtsthе сlеaг dеfinitе linе, whiсh usеd to mark thе сommеnсеmеnt of thе human

918

Wbеlc,еll pеriod of thе еarth,s history, madе oЬsсurе and douЬtful . . . It is truе that a rесonсiliation of thе sсiеntifiс with thе rеligious viеws is still possiЬlе, Ьut it is not so сlеar and striking as it onсе was. But it is still a wеaknеss to rеgrеt this; and no douЬt anothеr gеnеrationwill find somе way of looking at thе mattеr whiсh will satisfy rеligious mеn. I should Ье glad to sее my Way to this viеw, and аm hoping to do so soon. (Todh u n t е r1 8 7 6 , 2 : 4 З 5 4 З 6 ) !Иhеwеll had always Ьеliеvеd in thе diсtum that truth сannot Ье opposеd to truth. Еspесially, аs notеd еаrliеr' his wаs not аn opposition to еvolution bзsеc оn з сrudе l-jbliсз'lljrеrзljsm..Asзlrlз;'s, nэfш,.зJrhеоJog; rr,зsз {if поr thе) ma1or faсtor. Darwin may not havе Ьееn mеntionеd Ьy namе in thе nеw prеfaсе tо thе Bridgеwatеr Trеatisе. This did not stop Whеwell from quoting and thеn strongly disagrееing with passagеsin thе origiп whеrе Darwin tгiеd to show that produсing thе еyе did not nесеssaгilyhаvе to supposе a dirесt intеrvеntion of thе Сrеаtor. By thеn, howеvеr, timе hаd movеd on and a nеw gеnеration of геligiоus thinkеrs Wеrе trying to show why еvolution provеs dеsign' rathеr than why dеsign rеfutеs еvolution. BIвLIoGRAPHY Barrеtt,P. H., P.J. Gautrеy,S. HеrЬеrt,D. Kohn, and S. Smith,еds.1987.Сhаrlеs Dаrtuiп'sNotebooks,18З6-1844.Ithaсa,NY: СornеllUnivеrsityPrеss. СhamЬеrs,R. 1844. Vеstigеsof the Nаtиrаl Historу of Сrеаtioп'l,ondon:Сhurсhill. Darwin, С. 1'871.Tbe Desсеntof Мап, аnd Sеlесtiсlпiп Relаtioп /o Sex. London: John Murray. 1959. The Оrigiп of Spеciesbу Сhаrles Dаrшiп: А Vаriorum Tехt. М. Pесkham,еd.Philadеlphia: Univеrsityof Pеnnsylvania Prеss. -Гhе 1993. Ссlrrеspсlпdепсе of СhаrlеsDаrtuiп' Vol. 8. СamЬridgе: СambridgеUnivеrsityPrеss. Di Grеgorio,M.' аnd N. \и. Gill, еds.1990.СhаrlеsDаruliп'sМаrgiпаliа.Уo|.|. Nеw York: Garland. 'Williаm Douglas,S., еd. 1881. Thе Lifе аnd Sеlесtirlпsfrom thе Сorrеsprlпdепсе of Whеcuеll, D.D.2 vols.London:КеganPaul. Fisсh, M. I991. Williаm Wheшell,Philosophеrof Sсiепсе,oxford: oхford UnivеrsityPrеss. Fisсh' M.' and S. Sсhaffеr,еds. 1991. \Yilliаm Whешеll:А СompositеPortrаit' Oхford: Oxfоrd UnivеrsityPrеss. Garland, М. М. 1980. СаmbridgеbеforeDаrluiп: The ldеаl сlfа Libеrаl Еduсаtirlп, 1800-1860. CamЬridgе:CamЬridgеUnivеrsityPrеss. Gillеspiе,с. с. 1950.Gепеsisапd Gеologу.СamЬridgе,МA: HarvardUnivеrsity Prеss. Gould, S. J., and R. С. Lеwоnttп.1979.Thе spаndrеlsof San Marсo and thе Panglossianparadigm:A сritiquеof thе adaptationistprogramme.Proceеdiпgs of thе RoуаlSoсietуof Loпdon,SеriеsB 205: 581_.598. .!Иhеwеll's Hеrsсhеl,J. F. !и. 1841.Rеviеwof History and Philosophу.Quаrterlу Rеuieш135 177-2З8. -Гhе Каnt, I. |1790] 1928. Сritiquе of TеlеoklgiсаlJudgеmепt.J. С. Mеrеdith' trans. Oxford: Oхford UnivеrsityPrеss. Kavalowski,У. 1974, Thе ..vеraсausa,'prinсiplе:An historiсo-philosophiсal study of a mеtathеorеtiсalсonсерtfrom Nеwton throughDarwin. UnpublishеdPhD thеsis,Univеrsityof Chiсago'

,l'848. Owеn, R. Оп tl London: Voorst. 1'849.Оп thе Palеy,\й. [1802]1819 Rivington. Rusе,M. 1975.Darw thе philosophiсa dеvеlopmеntof С Philosophуof Sсi 1979.Thе Dа Univеrsityof Сhiс 1991.!Иilliam Williаm Whешеll Prеss. 2001.Introdu of tbе FirstЕditio thе Аuthor lust Bt RеbuttiпgHis Сri, Univеrsityof Сhiс 2О03.Dаrшiп МA: Harvard Uni Snydеr,L. J.2О06.Rе Soсiеtу.Сhiсago:i Todhuntеr,I. \876, w, Ап Ассouпtof Нi: Сorrespoпdеnсе2 .VИhеwеll, W. 1833.Аs to Nаturаl Тheolo (7th ed.,1864.1 1837.Thе Нis Timе. З vols.Lonс 1840.Thе Phil Pаrkет. 1845,lпdiсаt 1 8 5 3 .О f t h еР

Wilbеrforсе'saп

SamuеlЧ/ilЬеrforс the suссеssfulfight a SamuеlWilЬerforсе Low Сhurсh fathеr'l try. Sеvеralof his rе Сardinal) Hеnry М tеmptеd.Indееd'Joh сomе a сardinal,lеа himsеlfand wilЬеrfс forеmosta man am tional сhurсh. WilЬеrfоrсеwas сl sition that hе bесam

Wilbеrforсe

sсurе аnd douЬtful . . . It is tгuе th thе rеligiousviеws is still posg as it onсе Was. But it is still a ,nothегgеnеratiоnwill find somе satisfyrеligioшsmеn. I should Ье am hoping to do so soon. (Todсtum thаt truth саnnot Ье opposеd Was not an opposition to еvolution Й/ays'гlaturalthеology was a (if not lееn mеntionеdЬy nanrе in thе nеw did not stоp.Wlrеwеllfrom quoting 'еsin thе Оrigiп whеrе Darwin triеd lесеssaгilyhavе to supposе a dirесt еvеr' timе had rrrovеdon аnd a nеW lg to show why еvolution provеs dеrtion.

еds.1987.Сhаrlеs ohn,and S. Sn-rith, '' NY: СornеllUnivеrsityPrеss' listorу of Сrеаtioп,London: Сhuгсhill. ''еlесtioп iп Rеlаtbп lo Sex. London: lеs Drlпuin:A Уаriorum Техt. Prеss. r of Pеnnsylvaniir 's Dаrшiп,Vol. 8. СamЬridgе: СhаrlсsDаnuiп's МаrgiпаIiа.Vol. 1. сlf Williаm s frсlmthе Сrlrrеspoпdепсе aul. еr of Sсiепсе.oxford: Oхford l Whешеll:А СompositеPortrаit. rш,in:Тhе Ideаlof а I-iberаlЕdисаtion, versit,vPrеss. MA: Harvard[lnivеrsity СamЬridgе, spandrеls of SanМarсo and thе adаptationistprogrammе.Proсeediпgs 20-5:581-598. s History and Philosophу.Quаrtеrlу lgiсаlJudgеmеnt. J' С. Меrеdith,trans. study :iplе:An historiсо-philosophiсal on throughDarwin. UnpuЬlishеdPhD

owеn, R. |848. Оп thе Аrсhetуpе апd Homсllсlgiеs of thе Vеrtebrаtе Skеlеtoп. London: Voorst. 1'849. Оп the Nаture of Limbs. London: Voorst. Palеy, W. [1802] 1819. NаturаI Theolrlgу (Сollected Works, vol. 4). London: Rivington. Rusе, М. 1975. Darwin's dеbt to philosophy: An еxamination of thе influеnсеof .W. .!7hеwеll thе philosophiсal idеas of John F. Неrsсhеl and lfilliam on thе dеvеlopmеnt of Сhaгlеs Darwin's thеоry of еvolution. Studiеs iп Нistorу апd Pbiloso1lbуof Sсiеncе 6:159-181' 1979. Tbе Dапuiпiап Rеuolution: Sсiеttсе Red iп Tooth апd Сlаu,,.Сhiсago: Univеrsity of Сhiсagо Prеss. .DИhеwеll: 199 l. !7illiam Omnisсiеntist. In М. Fisсh аnd S. Shаffеr. еds.. Williаm Whешell: A Сtlmposite Portrаit' 87-1|6. oxfoгd: oxford Univеrsity Prеss. .W.. 'Worlds: 200 1. Introduсtion. !7hewеll. In Оf the Plurаlitу of А Fаcsimile of thе First Еditioп of 185З: Plцs Preuiouslу Uпpublisbеd Маteriаl Ехсised bу thе Аuthor .|иstBeforе tbe Bсlok Weпt to Prеss: And whеluell's Diаlogие Rebuttiпg His Сritiсs, Rеpriпtеd from t|lе Seсoпd Еtlitioп, 1_31. Сhiсago: Univеrsity of Сhiсago Prеss. 2003. Dаrtl,iп апd Desigп: Does Еuolutioп Hаuе а Purposе? CamЬridgе, МA: Harvard Univеrsity Prеss. Snydеr, L. J. 2006. Rеformiпg Phibsophу: A Victoriап Dеbаte oп Sсiеltсе апd Soсiеtу. Сhiсago: Univеrsity of Сhiсago Prеss. Todhuntеr' I. 1876. Williаm Wbеu.lеll,D.D., Маstеr of Triпitу Сollеgе' Саmbridgе: Ап Aсcсltlпt of His Writiпgs tuith Sеlections from Нis Literаrу апd Scieпtifiс Сorrеspondenсe , 2 уo|s, Londorr: Mасmillan. Whеwеll, !и. 1833. Аstrсlпomу апll Gепеrаl Phуsiсs Сonsidеrеd tuith Rеfеrenсе .William to Nаturаl Theologу (Bridgеwatеr Trеatisе' 3). London: Piсkеring. (7thеd..1864.) 18З7. Tbе Нistorу of tbе Indltctiuе Sсiепсеs, from thе Еаrliest to thе Presепt Timе. З vols. London: .|ohn W. Parkеr. .!(. \840. Тhe Philosopbу сlf thе lпdисtiuе Sсiеnсеs. 2 vols. London: John Parkеr. 1845. Iпdiсаtiotlsr'lfthе Сreаtсlr.London; John W. Parkеr. (2nd еd., 1846.) -М.R. 1853. Оf thе Plurаlitу of Worlds. Londoп: John !И. Parkеr.

Wilbеrforсе'samuеl(1805-1873) .WilЬеrforсе .Wilbеrforсе, Samuеl was thе third son of William а lеаdеr in fight thе suссеssful against owning and sеlling slavеs in thе British Еmpirе. Samuеl WilЬеrforсе Was ordainеd in thе Сhurсh of Еngland and, unlikе his Low Сhurсh fathеr, Ьесamе a lеadеr of thе High Сhurсh forсеs in thе сountry. Sеvеral of his rеlativеs, inсluding his Ьrothеr.in-law Arсhdеaсon (latеr Cardinal) Hеnry Мanning, сrossеd ovеr to Romе' Ьut hе was nеvеr tеmptеd. Indееd,John Hеnry Nеwman, himsеlf to сгoss ovеr and latеr Ьесomе a сaгdinal, lеadеr of thе oxford Мovеmеnt, put distanсе Ьеtwееn himsеlf and \й/ilЬеrforсеЬесausеit was сlear that !ИilЬеrforсе was first and forеmost a man amЬitious for soсial and eссlеsiastiсal suссеss in thе national сhurсh. \WilbеrforсеWas сrеatеd bishop of oxford in 1845, and it was in this po. sition that hе bесamе a figurе of history. In 1860 thе British Assoсiation for

920

Wilberforсе thе Advanсеmеnt of Sсiеnсе-an annual jamЬorее that attrасtеd Ьoth profеssionals and laypеoplе-hеld its mееtings in oхford. Thе yеar aftеr thе puЬliсation of Сharlеs Darwin's Оп the Оrigiп of Spесiеs,thе topiс of еvolution Was on thе minds of all. Riсhard owеn, thе anatomist and hatеd rival of thе Darwinians' put thе Ьishop up to dеbating with Darwin's Ьulldog, Thomas Неnry Huxlеy. Thе еnсountеr Ьесamе lеgеndary,with thе Ьishop-so wеll krrown for his smooth dеЬating stylе that hе was niсknamеd ..Soаpy sam''-supposеdly asking Huхlеy if hе was dеsсеndеdfгom monkеys on his fathеr's sidе or his mothеr,s sidе, and Huхlеy rеsponding that hе had rathеr Ье dеsсеndеd from a monkеy than from a Ьishop of thе Сhurсh of Еngland. Lеgеnds sеrvе a purposе' Ьut thеy аrе not nесеssarilytruе. It is improЬaЬlе that things wеrе quitе this sharp. Сontеmporary aссounts suggеstthat all had a jolly good timе and proЬaЬly Wеnt off togеthеr aftеrward for good food and drink. Сеrtainly thе rеviеw that WilЬеrforсе Wrotе of tЬe Оrigiп in the (сonsеrvative)Quаrtеrlу Rеuiеш was сritiсal Ьut dееply rеspесtful.But for thе Darwinians thе story sеrvеd a wondеrful puгposе Ьесausеthе young and vеry middlе-сlassHuxlеy took on thе uppеr-сlаsspillar of thе еstablishmеnt

and purportеdly grol Falstaff and thе roЬЬ Fаir of Huхlеy and V thе lattеr in thе Еlizal thе forward-lоoking ' of rеligion. \WilЬеrforсе diеd al for thе first timе in hl world, and it killеd h

BlBLIoGRAPн

Dеsmond'А. 1994.Hи Luсas,J. R. 1979.!иilb Jourпаl22: З13_3 Nеwsomе'D. 1966.Th London:John Mur .WilЬеrforсе' s. 1860.R 225-264.

Williams, Gеorgс

Lеft: BisЬop William WilЬеrforсе (1869).RlgЙr: Thomаs Hеnry Huxlеу '11871). Тhеsе two сartoons' Ьy thе artist ..Ap.,'' Саrlo Pеllеgrini,appеarеdin thе wееkly magazinе Vапitу Fаir. Somе suggеstthаt thе niсknamе ..SоapySаm'' сomеs from \WilЬеrforсе's hand-washinchаЬit. as shown in thс сartoon.

Gеorgе Iй/illiams is < modеrn timеs, сastin plinе. Trainеd in iсht thе Univеrsity of Сa on thе есology and е tion among еvolutioл sеs and synthеsеs.H senеsсеnсеhavе сhan сеss of natural sеlес thе fiеld. In his rеmarkaЬlе l alphaЬеtiсal еntry in tl as Daгwin postulatеd сhangе and divеrsifiсa еral сontrovеrsial aspе tivе еvolution еngеnd Ьy.produсt of thе Dа book, and onе to whi( ination of thе lеvеl at sеlесtion at thе lеvеls argumеnts wеrе partiс Harnilton hаd reсеntl of thе gеnе сould Ье a есologists Wегееngаg winian sеlесtionand l inspiring hypothеsеs с

922

Williаms of thе population or spесiеs(group sеlесtion;sееthе alphaЬеtiсalеntry in this .Williams's forсеful argumеnts against thе prеvailirrgformulations volumе). of group sеlесtion influеnсеd gеnеrations of еvolutionary Ьiologists and playеd a rolе in dеlaying thе gеnеral aссеptanсеof morе sophistiсatеdviеws of group sеlесtion. lndееd, tеaсhers of еvolution сontinuе to есho \Х/illiams еaсh timе thеy rеmind studеnts that adaptations havе not еmеrgеd for thе bеnеfitof thе population or spесiеs.(Thе philosophеr Еlliott SoЬеr'sThе Nаture of Sеleсtioп [1984| is a syrтpathеtiсif somеtimеsсritiсal ехаnrinationof .!Иilliаms's thinking. ) Natural sеlесtion in its myгiad manifеstations has Ьееn thе foсus of Williams's work throughout his сarееr.In his Ьook Sех апd Еuсllutioп (|97 5) Williams foсusеd on thе quеstion of how and why sехual rеproduсtion еvolvеd and Ьесamе so prеvalеrrt.Pгеvious argцmеnts aЬor'rttlrе еvolution of sеxual rеproduсtion had Ьееn foсusеd on a limitеd rangе of populatiоn-gеnеtiсissuеs. \й/illiams rееxaminеd what othеrs hаd suggеstеd and Ьroadеnеd thе topiс tо inсludе thе есologiсal and soсial сonsidеrations that surround sехual rеproduсtion. In doing so, hе Ьrought thе topiс to widеr attеntion and grеatеrprominеnсе and inspirеd sеvеrаl rеsеarсh progrаms dеdiсatеd to tеsting thе idеаs .!Иhеtlrеr hе Ьad raisеd. sехual геproduсtion in highеr organisms hаs Ьесomе more Ьurdеn than аdvantagе'as Williаms suggеstеd'rеmains undеr еmpiriсal sсrutiny. Williams is also rеsponsiЬlе for onе of thе dominаnt hypothеsеs for thе ехistеnсе of sеnеsсеnсе' thе so-сallеd antagonistiс plеiotropy aгgumеnt. Whеn Williams offеrеd lris hypоthеsis, thе prеvailing idеa аЬout sеllеSсеnсе was that it was thе геsult of dеlеtеriousgеnеswhosе ехprеssion was dеlayеd until latеr agеs. This idеa was Ьasеd on thе argumеnt that natural sеlесtion would Ье morе еffесtivе at purging dеlеtеrious gеnеs that wеrе еxprеssеd early in lifе Ьесausе tlrosе gеnеs wоLrld sеvеrеly ссrnrpromisеfitnеss,еspесially if thеy wеrе ехprеssеd during аn individual's rеproduсtivе prirnе. Gеnеs with dеlеtеrious еffесts ехprеssеd latе irr lifе would aссumulatе Ье.sИilliams suggеstеd that sеnеs. сausе thеy would havе littlе еffесt on fitnеss. сеnсе сould Ье сausеd Ьy gеnеs that wеrе еxprеssеd throughout an individual's lifе but had Ьеnеfiсialеffесtsеarly and dеlеtеriousеffесtslаtе.In this hypothеsis thе еarly Ьеnеfiсial еffесts outwеighеd thе lаtеr dеlеtеrious effесts' and so sеlесtion would not еliminatе thosе gеnеs.Althouglr thе distinсtion Ьеtwееn thеsе hypothеsеs may sееm suЬtlе, it addrеssеsthе important quеstion of how oftеn and how muсh adaptation rеquirеs сompromisеs Ьеtwееn gеnеs that аffесt thе samе individual and Ьеtwееn thе multiplе еffесts of individual gеnеs. Indееd' thе issuе of сompromisе, еspесially Ьеtwееn gеnеtiс еffесts at diffеrеnt аgеs, lrаs Ьееn arguеd Ьy \йiilliams to liе bеnеath thе largеr proЬlеm of agе-spесifiсtrait ехprеssion and tЬе individual's entirе lifе history (inсluding tlrе so-сallеd сost of rеproduсtion). Еvolutionary Ьiologists and ехpеrimеntal gеrontologists havе Ьееn dеvoting thе past 40 yеars to disсriminating Ьеtwееnthеsе hypothеsеsfor sеnеsсеnсеand to tеsting thе prеvalеrrсеof gеnеtiс сorrrpromisеsin lifе history in a host of сontеxts.

Iп Wil/iаmsЪ latсr v adaptation ro thе srud' г i е s o f a r g u m е n t st h a t сinе (sее thе main еss Меdiсinе'' Ьy МiсhaеI to mеdiсinе thе sсiеnris еvolutionary histoгy to l o g i с a l е x t е n s i o no f W i fеtal intеraсtions in prс еasеs' a variеty of mеd а n a | y s i sD . а r w i n i а nm t hаvе yеr to pеnеtгаtеfu \ W i l il a m s ' sс o n t г i b u t nuпlеrous awards' I]Iе logiсal Soсiеty of Amеr еmy of Arts and Sсiеn |999 he sharеd thе С M a y r f o r t h е i rp i o n е е r в|вLIoGRAPHY

Nеssе,R. М., and G. с. l Dаrtuiniаn Меdiсitlе SoЬеrЕ , . | 9 8 4 . Т h еN а t t WilliаmsG , . С . | 9 6 ь .А d UnivеrsityPrеss. | 9 7 5 .S е ха n d Е u |992. NаturаlSе Pr Oxfoгd Univегsity 1997.ThеPoпуF Nаturе. Nеw York: B

Wilson, Еdwаrdo

.Wilson is Еdward o. wa Amеriсan South, hе thеn shortly thеrеaftеrl of his aсadеmiс сагееr' u l t у m е m Ь е ra n d е v е n t sity profеssors.Не hаs v and foгеign awards' аn and tЬе rесipiеntof nlal е х p е r i е n с е si n h i s а u t o thе militaristiс сulturе с was vеry satisfying for tion of oЬsеrvationand Нis work has Ьееn r r o o t е d i n h i s s t u d i е st -

'Wilsoп sее thе alphaЬеtiсal еntry in this inst thе prеvailing formulations оf еvolutionary Ьiologists and nсе of morе sophistiсatеd viеws ttion сontinuе to есho Williams tions havе not еmеrgеd for thе losophеr Еlliott SoЬеr's The Nаlmеtimеs сritiсal ехamination of tations has Ьееn thе foсus of Ьook Sex апd Еuolиtion (1975\ why sехual rеproduсtion еvolvеd .s aЬout thе еvolution of sехuаl n g е o f p o p u l а г i o n . g е n е t i sс s u е s . ;tеd and Ьroadеnеd thе topiс to s that surround seхual reproduсI е гa t t е n t i o na n d g r е а t е гp r o m i s dеdiсatеd to tеsting thе idеas n highеr organisms has Ьесomе gеstеd,rеmains undеr еmpiriсal е dominant hvpothеsеs for thе gonistiс plеiotropy argumеnt. геvailingidеa aЬout sеnеsсеnсе whosе ехprеssion was dеlayеd tr8umеntthat natural sеlесtion )us gеnеs that wеrе еxprеssеd rеly сompromisе fitness' еspеlividuаl's rеproduсгivеprimе. : in lifе would aссumulatе Ье\Williams suggеstеdthat sеnеs)rе еxprеssеd throughout an ,and dеlеtеriousеffесtslatе. In Ltwеighеdthе latеr dеlеtеrious thosе gеnеs. Although thе diss u Ь t l е ,i t a d d г е s s е st h е i m p o г l p t a t i o n r е q u i г е sс o m p г o m i s е s I and Ьеtwееn thе multiplе еfrf сompromisе, еspесially Ьеееn arguеd Ьy \Х/illiams to liе Lit ехprеssion and thе individl сost of reproduсtion). Еvoluogists havе Ьееn dеvoting thе hypothеsеsfor sеnеsсеnсеand Lsеsin lifе history in a host of

.!7illiams's In latеr yеars hе appliеd thе prinсiplеs of natural sеlесtion and adaptation to thе'study of disеasе. \Х/ith Randolph Nеssе hе dеvеlopеd a sеriеs of argumеnts thаt havе сomе to Ье known gеnеrally as Darwinian mеdiсinе (sее thе main еssay ..Еvolutionary Biology of Disеasе and Darwinian Меdiсinе'' Ьy Мiсhaеl F. Antolin in this volumе). In a Darwinian approaсh to mеdiсinе thе sсiеntist-or thе physiсian-еxaminеs thе сondition in light of еvolutionаry history to undеrstand thе сondition's ultimatе origin. This is a logiсal ехtеnsion of \й/illiams's argumеnts aЬout sеnеsсеnсе.From matеrnalfеtal intеraсtions in prеgnanсy to thе gеnеtiс susсеptiЬility to partiсular disеasеs' a variеty of mеdiсal сonditions havе Ьееn illuminatеd Ьy Darwinian analysis. Darwinian mеdiсinе rеmains a young suЬjесt, and its impliсations havе yеt to pеnеtratе fully into сliniсal praсtiсе. Iй/illiams's сontriЬutions to еvolutionary Ьiology havе Ьееn rесognizеd Ьy numerous awards. Hе rесеivеd thе Еminent Есologist Award from thе Есologiсal Soсiеty of Amеriсa and is an еlесtеd mеmЬеr of thе Amеriсan Aсadеmy of Arts and Sсiеnсеs and thе U.S. National Aсadеmy of Sсiеnсеs.In 1999 he sharеd thе Сrafoord Prizе with John Maynard Smith and Еrnst Мayr for thеir pionееring and lasting сontriЬutions to еvolutionary Ьiology. в|BLIoGRAPHY .tJИilliams. .We Nеssе,R. М.' and G. С. 1'994''\Yhу Gеt Siсk:The Nеш Sciеnсеof Dаrшiniап Мediciпe.Nеw York: VintagеBooks. Sobеr,Е. 1984. Thе Nаtцrе of Selectioп.CamЬridgе,МA: МIT Prеss. Williams, G. С. 1966. Аdаptаtionапd Nаturаl Selectioп.Prinсеton,NJ: Prrnсеton UnivеrsityPrеss. 1975.Sех апd Еuolution.Prinсеton'NJ: PrinсеtonUnivеrsityPrеss. 1'992.Nаturаl Sеlеction:Domаiпs, Lеue|s,апd Сhаllепges.Nеw York: Oхford UnivеrsityPrеss. 1997. Thе Poпу Fish'sGloш аnd Оthеr Сlues to Plап апd Purposеiп -I 'T. Nаture. Nеw York: Basiс Books.

Wilson,Еdwardo. (b. Т929') .'0Иilson Еdward o. is today's lеading еvolutionаry Ьiologist. Born in thе Amеriсan South, hе was an undergraduatеat thе Univеrsity of AlaЬama and thеn shortly thеrеaftеr movеd to Harvard Univеrsity' whеrе hе spеnt thе rеst of his aсadеmiс сarееr' moving frоm graduatе studеnt to fеllow to junior faсulty mеmЬеr and еvеntually rеtiring as onе of thе most distinguishеd univеrsity profеssors. Hе has Won two Pulitzеr Prizеs, as wеll as many othеr domеstiс and forеign awards, and is a mеmЬеr of thе National Aсadеmy of Sсiеnсes and thе rесipient of many honorary doсtoral dеgrеes.Hе has rесordеd his lifе ехpеriеnсеs in his autoЬiography, Nаtцrаlist (1994)..!(ilson grеatly admirеs thе militaristiс сulturе of thе South, Ьut it is сlеar that thе еsсapе into naturе was vеry satisfying for a Ьoy and youth whosе own talеnts lay in thе dirесtion of oЬsеrvation and intеrprеtation. His work has Ьееn widе ranging Ьut Ьеgan and has always Ьееn dееply rootеd in his studiеs of thе soсial insесts' most partiсularly ants. His еarly

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Wilson work Was on сlassifiсation аnd Ьiсlgеography and was Ьasеd Ьoth on musеum study and on fiеldwork, partiсularly in thе }.ar Еast. A major papеr, сowrittеn with a fеllow graduatе studеnt on thе suЬspесiеs сonсеpt (Wilson and Brown 195З), еarnеd thе lasting irе of Еrnst Mayr, thе lеading taxonomist and major figurе in thе Harvard Мusеum of Сomparativе Zoology. Inсrеas. ingly in thе 1960s Wilson turnеd to morе tесhniсal issuеs in Ьiogеography and with thе thеorеtiсiаn thе latе Robеrt MaсArthur Was thе author of a maior hypothеsis aЬout thе ways in whiсh islands aсhiеvе spесiеsеquiliЬrium, with numЬеrs of inсoming spесiеsеqualing outgoing (gеnеrally through ехtinсtion) spесiеs(Мaсarthur and.Wilson 1967). \Х/ithhis studеntDan SimЬеrloff,Wilson сonduсtеd сlassiс ехpеrimеnts that triеd to show thе еmpiriсal truth of this work. Onе of thе Ьеst-known involvеd an islеt off thе сoast of Florida whеrе \Wilson and SimЬеrloff dеstroyеd all thе animal lifе and thеn rесordеd thе ratе at whiсh thе islеt was rеpopulаtеd. .lfilson Еvеn as hе was сomplеting this work, was moving into issuеsof animal сommuniсation and soon madе pathЬrеaking disсovеriеs aЬout how insесts usе сhemiсals (phеromonеs) to transfеr information to еaсh othеr. This sеt thе sсеnе for thе 797Оs,whеn Wilson produсеd a major trli,ogуzTbe Iпsect Soсiеtiеs(1971)' dеaling with thе naturе of soсiality among thе insесts; Soсiobiologу: The Nеu,, Sуnthеsis (1975), dеaling with thе еvolutionary Ьiolоgy Ьеhind thе soсiality of аll animals; and or Hцmап Nаtиre (1978), whiсh trеats еxсlusivеly of thе еvolutionary basis of human soсiality, and for whiсh Wilson Won thе first of his Pulitzеr Prizеs. .W.ilson's Sociobiolсlgу: Тhе Neш Sупthеsis was mаgnum opus and is now rесognizеd as onе оf thе major works in thе history of еvolutionary thеoriz. ing. It prеsеntеda hugе rеviеw of all that Was thеn known аЬout thе mесhanisms Ьy whiсh natural sеlесtionсan produсе soсial Ьеhavior, followеd Ьy a dеtаilеd rеviеw from thе lowеst forms to thе highеst of hоw suсh Ьеhavior aс. tuaily сan Ье found in aсtion. Nеvеrthеlеss,Ьесausе thе Ьook еnds with a сhaptеr that appliеs thе idеas to our own spесiеs'at thе timе of puЬliсation thе Ьook wаs highly сontrovеrsial. Мany-еspесially soсial sсiеntistswho fеlt thrеatеnеdfоr thе autonomy of thеir own studiеs,and Мarхist Ьiologists who hatеd any nonесonomiс аnalysis of bеhavior-launсhеd Ьittеr сritiquеs of thе Ьook. It was arguеd that thе Ьook wаs mеthodologiсallyflawed,that it 's7еstеrn wаs raсist and sехist, аnd that it was no morе than сapitalist idеology drеssеdup as oЬjесtivеknowlеdgе. .Wilsоn Brushing off сritiсism, did morе work in thе 1980s on human soсiality' еspесially with a young Сanаdian physiсist, Сharlеs Lumsdеn. At .W.ilson thе samе timе, сontinuеd to Work in Ьasiс sсiеnсе, thinking hard аЬout thе сonсеptual issuеsin thе fiеld of soсial Ьеhavior.This lеd to a сoauthorеd work with thе thеorеtiсianGеorgе ostеr (1978) on so-сallеdoptimality modеls. Inсrеаsingly, h
Morе rесеntly, Holldoh tions of soсioЬiology,a guе for a muсh morе hс aссount thе way that st into wholеs, whiсh sеlе ganisms in a сolсlny.Tl tЬe Оrigiп' Disintеrеstе с r i t i с s a с с u s е dh i m o f r standaЬlе in tеrms of pz Always intеrеstеdin ] son has turnеd his attег еthiсs with thе philoso1 tivе titlе Сonsilienсe (19 Ьеtwееn diffеrеnt ЬrаI .!Иilson has madе major forеsts-hе has writtеn us today (sеееspесially \й/ilson has Ье |20021). manism, in whiсh thе su еnsurеs thе futurе of tl сalls Ьiophilia, !flilson tionship with naturе,aг will Ье Ьoth physiсal an do all wе сan to prеvеn Although !Иilson has gion adds to thе world, sidеraЬlе sympathy for 1 his own еarly сhildhoo arguеd that today wе m a morе naturalistiс basе ogy' that motivatеd !Иil in Оn Ниmап Nаture) p|ea (Thе Сreаtioп,200 vation. Ultimatеly, \ffils history of lifе from sim with еvolutionary thinkr tееnth сеntury and Juli: this progrеss in itsеlf is 1 Nееdlеss to say, сlaim or with philosophеrs. lV tеrs of faсt and mattеrs ( progrеss' this is somеth than somеthing onе rеа whеthеr hе is right or и tions. Hе сannot Ьеliеvе unguidеd proсеss оf сh

Wilson 1y and Was Ьasеd Ьoth on mun thе Far Еast. A major papеr, thе subspесiеsсonсеpt (Wilson l s t M a y r , r h е l е a d i n gt a x o n o m i s t Сomparativе Zoo1ogу. Inсrеasесhniсal issuеs in Ьiogеography Arthrrrwas thе author of a major LсhiеvеspесiеsеquiliЬгium, with ng (gеnеrallythrough ехtinсtion) .!Иilhis studеnt Dan SimЬеrloff, l to show thе еmpiriсal trцth of an islеt off thе сoast of Florida hе animal lifе and thеn rесordеd on Wasmoving into issuеsof anlrеaking disсovеriеs aЬout how sfеr information to еaсh othеr. n produсеd a major trilrogу:Тbe r е o f s o с i a l i t ya m o n g t h е i n s е с t s ; aling with thе еvolutionагy Ьiol)п Humап Nаtиre (1978)' whiсh I human soсiality,and for whiсh lson's magnum opus and is now history of еvolutiоnary thеorizrs thеn known aЬout thе mесha:е soсial Ьеhavior,followеd Ьy a h i g h е s to f h o w s u с h Ь е h a v i o ra с , bесausеthе Ьook еnds with a lесiеs,at thе timе of puЬliсation -еspесiallysoсial sсiеntists who n studiеs,and Marхist Ьiologists t a v i o г - l а u n с h е db i t t е r с r i t i q u е s ; mеthodologiсаlly flawеd' that it lrе than lfеstеrn сapitalist idеol_ vork in thе 1980s on human sсlphysiсist, Сhаrlеs Lunrsdеn. At in Ьаsiс sсiеnсе' thinking hard сial Ьеhaviоr.This lеd to a сoaus t е r( 1 9 7 8 ) o n s o - с a l l е do p t i m a l _ rrnеd Ьaсk to his studiеs of ants. jlldoЬlеr, .Wilsonprodr,сеd masr thе сoauthorеd Ьook Tbe Аnts I his Pulitzеr Prizеs. In thе 1990s jor taхonomiс study of thе group.

.!Иilson havе Ьееn thinking aЬout thе foundaMorе rесеntly, HolldoЬlеr and ..supеrorganism,'(2008) artions of soсioЬiology, and in a nеw work on thе guе for a muсh morе holistiс approaсh to the topiс' onе whiсh takеs into full aссount thе way that soсial soсiеtiеs (еspесially in thе insесts) gеt intеgratеd into wholеs, whiсh sеlесtion trеats as individuals rathеr than as sеparatе organisms in a сolony. This was vегy muсh thе position of Сharlеs Darwin in tЬe Оrigiп' Disintеrеstеd oЬsеrvеrs sеnsе thе irony that in thе 1970s.!7ilson's ..rеduсtionism,'' trеating еvеrything as undеrсritiсs aссusеd him of unduе stаndaЬlе in tеrms of parts rathеr than wholеs. Always intеrеstеd in broadеr issuеs, inсrеasingly in morе rесеnt years-!Иilson has turnеd his attеntion to morе philosophiсal issuеs. Hе has writtеn on еthiсs with thе philosophеr Miсhaеl Rusе, and in a work with thе provoсa. tivе titlе Сoпsiliепсe (1998\ has artiсulatеd his own vision of thе сonnесtions Ьеtwееn diffеrеnt Ьranсhеs of knowlеdgе. An ardеnt сonsеrvationist.!Иilson has madе major еfforts in thе сampaign to prеsеrvе thе Brazilian rain forеsts-hе has writtеn ехtеnsivеly on Ьiodivеrsity and thе proЬlеms faсing us today (sее еspесiallу The Diuеrsitу of Lifе 119921 and Thе Futurе of Life [2002])..W.ilson has Ьееn arguing for a kind of еvolutionarily inspirеd humanism, in whiсh thе suprеmе moгal сommandmеnt must bе that whiсh bеst еnsurеs thе futurе of thе human spесiеs. An аrdеnt proponеnt of what hе сalls Ьiophilia, !Иilson arguеs thаt humans havе еvolvеd in symЬiotiс rеla. tionship with naturе' and unlеss thеy prеsеrvе thе world's flora and fauna, it will Ье Ьoth physiсal and spiritual dеath for thе human spесiеs.This wе must do all wе сan to prеvеnt. .Wilson has nеvеr Ьееn onе who arguеs that сonvеntional rеliAlthough gion adds to thе world's woеs, and although in somе rеspесts hе shows сonsidеraЬlе sympathy for thе rеligious mind-in part, undouЬtеdly, Ьесausе of his own еarly сhildhood сommitmеnts to еvangеliсаl rеligion-hе has long arguеd that today wе must undеrpin our moral and rеligious yеarnings with a morе naturalistiс Ьasе. It was this' rathеr than somе nеoсonsеrvativе idеology, that motivatеd NИilson in his еarliеr writings on humankind (еspесiаlly tn Оп Humап Nаturе\ and it сontinuеs to this day, еspесially in a hеartfеlt p|ea (Thе Сreаtion, 2006) to pеoplе of rеligion to join in thе work of сonsеr.Wilson finds his naturalistiс Ьasе in thе upward risе of thе vation. Ultimatеly, history of lifе from simplе to сompleх, from worm to human, and' in linе with еvolutionary thinkеrs of thе past (notaЬly НеrЬеrt Spеnсеr in thе ninеtееnth сеntuгy and Julian Huxlеy in thе twеntiеth сеntury), hе сlaims that this progrеss in itsеlf is justifiсation of all of his dеsirеd moral norms. Nееdlеss to say' сlaims likе thеsе do not find univеrsal favor with Ьiologists or with philosophеrs. Мany invokе David Humе's distinсtion Ьеtwееn mattеrs of faсt and mattеrs of valuе, arguing that еvеn though onе may Ьеliеvе in progrеss' this is something onе rеads into thе еvolutionary piсturе rathеr .Wilson is not сonvinсеd, and than somеthing onе rеads from thе piсturе. whеthеr hе is right or wrong' hе сеrtainly shows thе сouragе of his сonviсtions. Hе сannot bеliеvе that Ьеings likе humans, thе еnd produсt of a long, unguidеd pfoсеss of сhangе, do not show thе laЬors of that сhangе and

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Wilsoп should not Ье undеrstood in terms of that сhangе. This is truе of ants аnd, arguеs Wilson, must also Ье truе of Homo sаpieпs, (In a traditional way' Rusе 19B5 and Kitсhеr 2,0ОЗarе vеry сritiсal of \Vilsorr'sthinking. Мorе rесеntly' although not аll аpprесiatе \filson's progrеss-Ьasеdapproaсh' mаny arе starting to movе towаrd а naturalistiс stanсе on еthiсs and for this Wil. son dеsеrvеsmassivе сrеdit. Sее Rusе 1998'2008'2009'\ BIBLIOGRAPHY нdlldoЬlеr,B., and Е. O. Wilson. 199О,The Апts. СamЬridgе, MA: Нarvard UnivеrsityPrеss. 1994..|ournеуto tbе Ants: А Storуof SсiепtifiсЕхplorаtion. СarnЬridgе, МA: Haгvard UnivеrsityPrеss. 2008. Thе Supеrorgаnism:Tbe Beаиtу,Еlegапcе,аnd Strапgепеss of lпsесt Societiеs.Nеw York: Norton. Kitсhеr, P. 2003. Iп Мeпdel'sМirror. Nеw York: Oxford UnivеrsityPrеss. Lumsdеn,С. J., and Е. o. Wilson. 1'98\.Gепes,Мiпd, аnd Сulturе.Cambridgе, N4A:Harvаrd UnivеrsityPrеss. 198З. PromеtbеапFire: Rеflесtiottsoп thе Оrigiп of Мiпd. CamЬridgе,МA: Harvаrd UnivеrsityPrеss. .!Иilson. МaсArthur, R' H., and Е. O. 1967. The Thесlrуof lslапd Bbgеogrаphу. Prinсеton'NJ: PrinсеtonUnivеrsityPrеss. ostеr, G.' and Е. O. ]ff/ilson.1'978.Саstеапd Есologу iп thе Soсiаl lпsеcts. Prinсеton,NJ: PrinсеtonUnivеrsityPгеss. Rusе' М. 1985.Soсiobiologу:Seпsеor Noпseпse?2nd еd. Dordrесht:Rеidеl. |996. Мoпаd tсl Маn: The Сoпсеptсlf Progrеssiп Еt,rlllttioпаrуBiologу. СаmЬridgе,МA: Harvard UnivеrsitуPrеss. |998. Таking Dаrшiп Sеriсluslу:А NаturаlistiсАpproасh to Phibsophу' 2nd еd. Buffalo,NY: PrоmеthеusBoоks. 2008. СhаrlesDаrluiп. oхford: Blaсkwеll. -t ed.2009. Philosophуаftеr Dаrluin. Prinсеton,NJ: PrinсеtonUnivеrsity Prеss. Rusе,lvI.,аnd Е. o. Wilson. 198.5.Тhе еvolutionof morаlity.Nеtl Sсieпtist|478: 1 0 8 - 12 8 . 1986.Мoral philosophyas аppliеdsсiеnсе.Philosophу61 173_1'92, Sеgеrstralе, U. 2000. Dеfеndеrsof thе Тruth: The Bаttlеfor Sсiепсеiп the SoсiobiologуDеbаtеапd Beуoпd.Nеw York: Oхford UnivеrsityPrеss. SimЬеrloff,D., аnd Е. o. Wilson. 1969. Ехpеrimеntalzoogеographyof islands:Thе сolonizationof еmptyislаnds.Есolоgу 5О:278_296. Wilson,F,.o, \97|.Thе IпsесtSoсietiеs. СamЬridgе'МA: HarvardUnivеrsityPrеss. 1'975. Sociobiologу:Thе Nеш Sl'пthеsis.CаmЬridgе,МA: Harvaгd UnivеrsityPrеss. 1978. on Humап Nаturе. СamЬridgе,МA: CarnЬridgеUnivеrsityPrеss. 7984. Biophiliа. СamЬridge,МA: Нarvard UnivегsityPrеss. 1992' Tbe Diuersitуof Llfe. СamЬridgе,МA: Harvard UnivеrsityPrеss. |994. Nаtиrаllsr.!7ashington,DС: IslandBooks/Shеаrwatеr Books. 1'998.Сoпsilieпсe:Thе Unitу of Кпсltule/ge.Nеw Yсlrk:VintagеBooks. 2О02.Тhе Futurеof Lifе. Nеw York: Vintagе Books. 2ОО6.Тhе Сrеаtion:A Мееtiпgrlf Sсienсeапd RеIigion.Nеw York: Norton. 'Wilson, Е. O., and \й/.L' Brown Jr. l953. Thе suЬspесiеsсonсеptand its taxonomiс аppliсation.SуstеmаtiсZoolog1,2: 97_11I. Wright, R. 1987. ТbrеeSсiепtistsапd Тheir Gоds. Nеw York: Timеs Books. -М.R.

.Wright, Sеwall (18l

Sеwall Grееrr Wright, oI еvolцtion with R. A. Fis Was Ьorn on DесеmЬеr2 Sеwall Vright. Hе had \й/right family сan Ье r thе ninth.сеntury rеign t Massaсhusеtts, Ьut grеw faсulty of LomЬ:rrd Сo rеading at an еаrly agе.I by his сlassmatеs.In 190 matriсulatеd at LomЬarr thеr had enсouragеdhiш \Х/right'sintеrеstsin b: LomЬaгd through thе m оf thе first womеn to еaI Kеy sеnt Wright to Сol York, whеге \Wгightlеar mеr mеntor, Сharlеs Dz at Сold Spring НarЬor 1912. |n thе fall of 19]1 t h е U n i v е r s i t уo f I l l i n o i s By thе spring of 1912 of thе trеmatodе Мiсrot ordеr Ьесausеof a сhaп Еrnest Сastlе (1867 -19 (

studеnt of Dzrvеnport.С; rats and оn nrarnпralianр aЬout working with hrn Wright quiсkly finishеd l in thе fall of 1'912. At Harvard Wright еr logiсal gеnеtiсs. Wright' сonsidеraЬlу intluеnсеd At Harvaгd and thе But his hоodеd-гat sеlесtion By 1915 Wright сomplс guinеа pigs. \Vright's rе and allеlеs that affесtеd pothеSisthаt еnzymеpa, logiсal Ьаsis for oЬsеrvе thе timе Wright wаs fini mаl husЬarldmanat thе l

Мaryland. Wright's worJ a Ьiologist morе gеnеrаl

\Yright hat сhаngе' This is truе of ants and' omo sаpiепs. (In a traditional way, litiсal of \Wilson'sthinking. N{orе геon's progrеss-Ьasеdapproaсh, many гiс stanсе on еthiсs and for this Wilr 9 8 ,2 0 0 8 , 2 0 0 9 . )

, Аnts' СamЬridgе,МA: Нaгvаrd f SсiеntфсЕхplorаtioтt.СamЬridgе, пу, Еlеgаnсе,апd Strаngеltеssof Iпsесt (ork:oхford UnivеrsityPrеss. пеs,Мiпd, аnd Сulturе,СamЬridgе, oп the origin of Мiпd' CamЬridgе' МA: Thе Thеorуof lslапd Вhgeogrаphу. is. d Есologу iп thе SoсiаI lпsесts.

',Zn,"l zndеd.Dоrdrесht: Rеidеl. of Progress in Еuolutiсltlаrу Biologу. .еss. lаturаlistiс Approасh to Philosophу. ;. ;kwеll. Prinсеton, NJ: Prinсеton Univеrsity ution of morality. Nеш Sсiепtist 1'478 sсiеnсе.P hiloso1lhу 61,: 17 3_192. ': Тhe Bаttle for Sсieпсe iп the York: Oхford Univеrsity Prеss. lеrimеntаlzoogеographyof islands: Thе 50:278-296. mЬridgе' МA: Hаrvаrd Univеrsity Prеss. 'esls.Сambridgе, МA: Наrvard gе' МA: СamЬгidgе Univеrsity Prеss. Iarvard Univегsity Prеss. idgе, МA: Нarvard Univеrsity Prеss. Island Books/Shеarwatеr Books. п,uledge.Nеw York: Vintagе Books' l: Vintagе Books. сiеnсe аnd RеIigioп' Nеw York: Norton. rrеsuЬspесiеsсonсеpt and its taxonomiс 111. Gods. Nеw York: Timеs Books.

-м.R.

Wright,Sеwall(1889_1988) .Wright, onе of thе arсhitесts of thе modеrn synthеtiс thеory оf Sеwall Grееn еvolution with R. A. Fishеr (|890_|962) and J. B. S. Haldrrne (1,892_|964), .lfright and ЕlizaЬеth Quinсy was born on DесеmЬеr 27,1889, tо Philip Grееn youngеI ЬrotЬеrs' Quinсy and Thеodoге. Thе Sеwall Wright. Hе had t\^,ro !Иright fanrily сan Ье traсеd Ьaсk through siхtееnth-сеntury Еnglarrd to thе ninth-сеntury rеign of Сharlеmagnе. Sеwall \Иright was Ьorn in Mеlrosе, Massaсhusеtts,Ьut grеw up in GalеsЬurg' Illinois, whеrе his fathеr was on thе faсulty of Lon.rЬard Сollеgе. lХ/right and his Ьrothеrs wеrе giftеd сhildrеn, .!7right's аЬilitiеs сaцsеd him tormеnt rеading at an еarly agе. Indееd, in sсhool Ьy his сlassmatеs.In 1906 !7right graduatеd from GalеsЬurg Нigh Sсhool and matriсulatеd at LomЬard Сollеgе to study mathеrnatiсs and survеying; his fathеr had еnсouragеd lrinr to study his own lovеs, poеtry аnd musiс. !Иright'sintеrеstsin Ьiology took сеntеr stagеduring his last уeat, |9||,at LomЬard through thе mеntoring of Wilhеlminе Еntеman Kеy (who wаs onе оf thе first Womеn to еaгn a PhD at thе Univеrsity of Сhiсago). That summеr Kеy sеnt Wright to Сold Spring Наrbor LaЬoratory сlrr Long Island, Nеw York, whеrе'fi/rightlеаrnеd from world-сlass Ьiologists' irrсludingKеy's for.s7right fоund his еxpегiеnсе mеr mеntor' Chаrlеs Davеnport (t866_1'944). at Сold Spring НarЬor rеWarding' and hе rеturnеd during thе sцmmег оf |9|2.In thе fall oi191l1 Wright еntеrеdthе grаduatе program in biology at thе Univеrsity of Illinois, UrЬana-Сhampaign. By thе spring of |912 !Иright сomplеtеd his mastеr's thеsis on thе anatomy of thе trеmatode МiсrophаIlus opаctls. \Vright сomplеtеd thе thеsis in short ordеr Ьесаusе of а сhanсе mееting аftеr a lесturе Ьy thе gеnеtiсistWilliаm Еrnеst Сastlе (1867-|962), of Harvard Univеrsity's Bussеу Institutе,anothеr studеntof Davеnport. Сastlе lесturеd on his sеlесtionеxpеrimеntson hoodеd rats and on пratnmalian gеnеtiсs.Wright was fasсinatеdand approaсhеd Саstlе aЬout working with him. Сastlе was suffiсiеrrtlyimprеssеd Ьy Vright that .0Иrightquiсkly finishеd his mastеr's thеsis and еnrollеd at Harvard Univеrsity in thе fall of 1912. At Harvard Wright еngаgеd in oгiginal ехpеrimеntal геsеarсhin physio.lfright's rеsеarсh was dirесtеd by Сastlе, Ьut hе was also logiсal gеnеtiсs. сonsidеraЬlyinfluеnсеd Ьy thе gеnеtiсistЕdward Мurray Еast (1879_1938). At Harvard аnd thе Bussеy Institutе Wright workеd сlosеly with Сastlе on his hoodеd.rat sеlесtiol1ехpеrimеntsand on thе gеnеtiсsof small mammals. By 1915 Wright сonrplеtеd his doсtoral thеsis on сoat-сoloг inhеritаnсе in guinеa pigs. Wright's rеsеarсh dеmonstratеd thе ехistеnсе of multiplе lосi and allеlеs that affесtеd сoat сoloг in thе aniпral; it furthеr sеt out thе hypothеsis that еnzymе pathways and pigmеnt prесursorsprovidеd thе physiologiсal Ьasis for oЬsеrvеd pattеrns of inhеritirnсеof сoat сoloration. Around .!Иright was finishing his thеsis, hе aссеptеd a position as sеnior anithе timе mal husЬandman at thе U.S. Dеpartmеnt of Agгiсulturе (USDA) in Bеltsvillе, Mаryland. WrightЪ work as a phvsiologiсаl gеrrеtiсistpеrnrеаtеdhis work as a Ьiologist morе gеnеrallyand, in partiсular, his work in еvolutionary thеory.

9i

928

Wrigbt .!Иright

was with thе USDA for 10 yеars, from 191'5 to 1925. Hе сon. trollеd a largе-sсalеinЬгееdingеxpеrimеnt on guinеa pigs Ьеgun at thе USDA tn 1906. During his tеnurе at thе USDA Wright puЬlishеd widеly on phys. iologiсal gеnеtiсs' Ьut two main puЬliсations in 1921 stand out. Thе first, .Wright's ..Сorrеlation and Сausation'' (!7right 1927a), dеsсriЬеd invеntion of the mеthod of path analysis, that is, thе mеthod for еstimatingthе magni. tudе and signifiсanсе of hypothеsizеd сausal сonnесtions Ьеtwееn sеts of variaЬlеs.Thе othеr was a sеriеsof еssayspuЬlishеd undеr thе hеading ..Systеms of Мating,' (Wright 1921ь). Hеrе !7right usеd path analysis to ехplorе the numеrous fеaturеs of mating systеms' inсluding inЬrееding, assortativе mating' and thе еffесts of sеlесtion. 'Wright suЬsеquеntly aпa|уzedthе history of inЬrееding in Amеriсan shorthorn сattlе using path analysis.Also io |921r .Williarls, Wright marriеd Louisе a mеmЬеr of thе faсulty of Ьiolоgy at Smith Сollеgе. Thе \Х/rightsparеntеd thrее сhildrеn, ЕlizaЬеth Rosе, Riсhard' and RoЬеrt. |n 1926 Wright joinеd thе faсulty of biology at thе Univеrsity of Сhiсago. It was hеrе that Y/right's сontriЬution as an arсhitесt of thе synthеsis of .\Х/right's Darwinism and Меndеlism was сomplеtеd. most famous еssay' ..Еvolution in Mеndеlian Populations,'' was puЬlishеd in 1931. \й/right dеmonstratеd thе mathеmatiсi.rlunifiсation of Darwinian natural sеlесtion and thе prinсiplеs of Меndеlian hеrеdity, and hе соmmuniсatеd this Synthеsis in thе form of his faгlrous ..shifting Ьalanсе'' thеory of еvolution. Wгight usеd his famous adaptivе-landsсapеdiagram to сommuniсatе his thеoгy a .!Иright yеar latеr (Wright \932). Using his work as a physiologiсal gеnеtiсist, еmphasizеd gеnеtiс intеraсtion in еvolution Ьy wаy of thе following assumption: Bесausе thе fiеld of gеnе сomЬinations in a population is vast' gеnеs adaptivе in onе сomЬination may not Ье adaptivе in anothеr; сonsеquеntly' thе 6еld of joint gеnе frеquеnсiеsgradеd for adaptivе valuе will produсе a hilly lаndsсapе.Populations thus faсе thе proЬlеm of shifting from onе pеak to anothеr. \Wright solvеd thе proЬlеm of pеak shrfts with his thrее-phasе shifting.Ьalanсеproсеss.In thе first phasе, suЬdividеd populations would Ье sr'rЬjесtto gеnеtiс drift, pulling thеm into a ..vallеy.'' In thе sесond phasе, thosе populations would Ье draggеd up thе nехt pеak Ьy intradеmе sеlесtion, or within-group sеlесtion. In thе third phasе, thе global population woцld find thе highеst pеak Ьy intеrdеme sеlесtion, or population-struсturеd sеleсtion. \й/right'smathеmatiсаl analysis of thе rесonсiliation Ьеrwееn Darwinism and Меndеlism agrееd with thosе of thе othеr two synthеsis arсhitесts, R. A. Fishеr and J. B. S. Нaldanе. Howеvеr, Fishеr arrd Vright in partiсulaг disagrееd aЬout thе ехtеnt to whiсh gеnе intеraсtion wаs important in dеsсriЬing thе gеnеtiс Ьasis of еvolutionary сhangе. For Fishеr' who dеemphasizеdgеnеtiс intеraсtion, natural sеlесtion aсting on mutations of small еffесt was suffiсiеnt aссounting for most сumulativе еvolutionary сhangе. Indееd, lfright and Fishеr ultimatеly bесamе mirеd in a сontrovеrsy ovеr thеir altеrnativе undеr. stаndings of thе еvolutionaгy proсеss that lastеd until FishеrЪ death iп 1962. In 1955 Wright was suЬjесtеdto mandatory rеtirеmеnt from thе Univеrsity of Chiсago. Hе Ьесamе Lеon J' Сolе Profеssoгof Gеnеtiсs at thе Univеr-

.!Иisсonsin, sity of Мa. Wright was prolifiс th than thе puЬliсation opus, Еuolиtioп апd сulmination of his wol faсеs of Selесtivе Valr This еssay was a mos, аnd Еuolutioпаrу Biot diеd at thе age of 99 o pеlvis aftеr a slip on a .s7right Sеwall is rеn tionary biologists. Hir thought, and his stati gеnetiсs.N7right was tl Mеdal of thе Royal Sl еnсе in 1'966, and the thе man was dеsсriЬеd flinсhing whеn disсuss

вIвLIoGRAPHY

Pгtlvinе,W. B. 1986.Seи of Сhiсago Prеss. Wright,S. 1921a.Сorrе 557-585. 1921ь.Systеmr 1931.Еvolution 1932.Thе rolеs. еvolution.Proсееdi |968-1'978. Еuo Univеrsityof Сhiсаg l988. Surfaсеs o 115-123.

Wright yеars' from 1915 to 1925. Hе сonеnt on guinеa pigs bеgun at thе USDA tA \Wright puЬlishеd widеly on physсations in 1921 stand out. Thе first, .lfright's |921a|, dеsсribеd invеntion thе mеthod for еstimating thе magniсausal сonnесtions Ьеtwееn sеts of rys publishеd undеr thе hеading ..SysVright usеd path analysis to ехplorе m s , i n с l u d i n g i n Ь r е е d i n g 'a s s o r t a t i v е ght suЬsеquеntlyanalyzеd thе history Lttlеusing path analysis.Also in 1921 rЬеr of thе faсulty of Ьiology at Smith rildrеn, ЕlizaЬеth Rosе, Riсhard, and Ьiology at thе Univеrsity of Сhiсago. :l as an arсhitесt of thе synthеsis of эlеtеd. Wright's most famous еssay' s,,, Was puЬlishеd in 1931. !Иright ltion of Darwinian natural sеlесtion ry, and hе сommuniсatеd this synthеЬalanсе,' thеоry of еvolution. Wright iagram to сommuniсatе his thеory a .s7right k as a physioiogiсal gеnеtiсist' t i o n Ь y w a y o f t h е f o l I o w i n gа s s u m p ationsin а populationis vast, gеnеs эе adaptivе in anothеr; сonsеquеntly' еd for adaptivе valuе will produсе a hе proЬlеm of shifting from onе peak r of pеak shifts with his thrее-phasе rsе, suЬdividеd populations would Ье nto a ..vallеy.'' In thе sесond phasе, thе nеxt pеak Ьy intradеmе sеlесtion, 1asе,thе gloЬal population would find or population.struсturеd sеlесtion. rе rесonсiliation Ьеtwееn Darwinism i othеr two synthеsis arсhitесts, R. A. Fishеr and \X/rightin partiсular disltеraсtion was important in dеsсribing For Fishеr' who dееmphasizеdgеnеtiс nutations of small еffесt was suffiсiеnt tiоnary сhangе. Indееd, Wright and ltrovеrsy ovеr thеir altеrnativе undеrrt lastеd until Fishеr's death ln 1962. Lndatory rеtirеmеnt from thе Univеrе Profеssor of Gеnеtiсs at thе Univer.

.W.isсonsin, Madison, whеrе hе rеmainеd for thе rеst of his long сarееr. sity of \wright was prolifiс throughout. Pеrhaps thеrе is no Ьеttеr tеstamеnt to this than thе publiсation Ьеtwееn |968 and |978 of his four-volumе magnum opus, Еuolutioп апd the Geпеtiсs of Populаtioиs. Thеsе volumеs wеrе thе .!Иright's ..Surlast еssay' сulmination of his work in еvolutionaгy thеory. Yеt faсеs of SеlесtivеValuе Rеvisitеd,'' was publishеd thе yеar hе diеd (1988). This еssay wad a mostly favoraЬlе rеaсtion to his Ьiographу, SешаIl Wright .!Иilliam B. Provinе in 1,986.Wright аnd Еuolutioпаrу Biologу' puЬlishеd Ьy diеd at thе agе of 99 on Мarсh 3, 1988, duе to сompliсations from a Ьrokеn pеlvis aftеr a slip on an iсy sidеwalk during onе of his usual walks. .sИright is rеmеmЬеrеd as a towеring figurе among Amеriсan еvoluSеwall tionary biologists. His adaptivе'landsсapе diagram pеrmеatеs еvolutionary thought, and his statistiсal thеory of inЬrееding is standard in еvolutionary .!0'еldon gеnеtiсs.Y/right was thе rесipiеnt of numеrous awards, inсluding thе Меdal of thе Royal Soсiеty of London tn 1'947, thе National Меdal of Sсiеnсе in 1'966, and thе Mеdal of thе Royal Soсiеty of London in 1980. \Wright thе man was dеsсriЬеd Ьy his friеnds and assoсiatеs as shy Ьut warm, and unflinсhing whеn disсussion turnеd to his intеrеsts. в|BLIoGRAPHY Provinе,!и. B. 1986. Setuаll'Wrightапd ЕuolиtioпаrуBiologу. Chiсago:Univеrsity of Сhiсago Prеss. Wright, S. 1,921a.Corrеlаtionand сausatiоn. Journаl of AgriculturаlResеаrсh2О: 557-585. 192|ь. Systеmsof mating.Gепetics6:1I\_178. 1931.Еvolutionin Меndеlianpopulations.Genеtiсs3:97-\59. \9З2.TЬe rolеsof mutation'inЬrееding, сrossЬrееding and sеlесtiоnrn еvolution.Proсееdiпgsof thе Siхth Аппuаl Сoпgrеssof Gепеtics7:356-366. 1968_Т978.Еuolutiсlпаnd thе Gепetiсsof Populаtioпs.4 vols. Chiсago: Univеrsityof Сhiсago Prеss. 1988. Surfaсеsof sеlесtivеvaluе rеvisitеd.AmeriсаnNаturаlist 1'31:

|t5-12З.

-R.А.s.

YaЬlokoч Alеxеi v. (b. 1933) Alеxеi YaЬlokov has madе suЬstantial сontriЬutions to Ьiogеtlgraphyаnd сonsеrvation through his innovativе usе of еasily mеasurеd, disсrеtе|уvarуing ехtеrnal сharaсtеrs suсh as pigmеntation pattеrns. Although Ьiologists havе always takеn advantagе of suсh variations-rесall that Меndеl's ехpеrimеnts wеге foсusеd on round or wrinklеd pеas and yеllow or grееn pеasYaЬlokov dеmonstratеd how thеsе сharaсtеrs сould Ье usеd in a variеty of сontехts' from еluсidating thе family Struсturе of dolphin grouPs to traсing thе long-tеrm еffесts of еnvironmеntal pollution. YaЬlokov сallеd thеsе disсrеte variations in сolor or rnorphology pbenеs, and his Ьook Phепetlсs is a synthеtiс trеatmеnt of how thе study of phеnеs сan Ье appliеd to almost еvеry topiсal arеa of еvolutionary Ьiology. YaЬlokov, a protёgё of thе population gеnеtiсist Nikolai TimofееffRеssovsky, rесеivеd his doсtoral dеgrее in 1'965 at thе NovosiЬirsk Statе Univеrsity. His еarly work in pоpulаtion gеnеtiсslеd him to thе phеnеtiсapproaсh as a Prасtiсal mеans of studying miсroеvolutionary proсеssеsrn natural populations and сonnесting thеm to Ьroadеr proЬlеms in Ьiogеogrаphy and сonsеrvation.Thеsе сonnесtions arе dеsсriЬеdtn Pbeпеtiсs'as wеll as in two othеr Ьooks in Russian (сoauthoгеdwith Timofееff-Rеssovskyand сolleagues).YaЬlokov has also Ьееn a lеadеr in thе study of fluсtuating asymmеtry' whiсh is a randomly asymmеtriс pattеrn that сan rеflесt a variеty of dеvеlopmеntal and gеnеtiс influеnсеs, and hе Was onе of thе first sсiеntiststo apply fluсtuating аsymmеtry to сonsеrvationissuеsЬy showing that pollution was inсrеasingthе lеvеl of asymmеtгyin skulls of graу sеals.Не has also puЬlishеd еxtеnsivеly on thе есology and gеnеtiсs of whаlеs and sеals and pionееrеd thе usе of сolor pattеrns for individual idеntifiсation and thе traсing of familiеs and pеdigrееs.In his latеr yеars hе has Ьесomе onе of Russiа's lеading сonsеrvationists;hе sеrvеd in thе Russian parliamеnt,was sсiеnсеadvisеr to Boris Yеltsin, and startеd a numЬеr of сonsеrvation orgаnizations. YaЬlokov's work has Ьееn еnormously influеntiаl in Russia аnd Еuropе' pаrtiсularly whеrе thе usе of morе еxpеnsivе,morе dirесt molесular gеnеtiс mrthods has Ьeen impraсtiсal. His phenеtiс approaсh has two paraliеls.Fiгst, thе usе of phеnеs to study natural sеlесtion rесalls thе есologiсal gеnеtiсsof Е. B. Ford and his stlldеnts and сollеaguеs. Indееd, many of thе еxamplеs offеrеd in Pheпеtics сan also Ье found in Ford's finаl еdition of Есologiсаl Gепеtiсs. Sесond, thе usе of phеnеs to study Ьiogеography,whiсh YaЬlokov 9З0

сallеd phеnogеographу ular markеrs for undеr h a v с s h a p е ds p е с i е sr а I Unfortunatеly, YaЬlс h i s w o r k h а s Ь е е nt r a n сontributions еmеrgеs whiсh hе workеd.Hе' Union duгing thе Lysеr s с i е n t i s t sh а v е i n е q u i p t a l i s s u е si n a p l a с е а n < do so. вlвLloGRAPHY

Y a Ь l o k о v^ , .У.1986.Ph Nеw York: ColumЬiс

Yаblohou саllеd phеnogеography,has its parallеl in thе usе of Ьioсhеmiсаl and molесulаr markегs for undеrstandinghow dispеrsal pattеrns and historiсal еvеnts havе shаpеd spесiеsrangеs. Unfortunаtеly, YaЬlokov's rеputation in thе 'Wеstis limitеd Ьесaцsеlittlе of

:ial сontributions to biogеography and usе of еasily mеasurеd, disсrеtе|у varуnеntation pattеrns. Although Ьiologists variations-rесall that Меndеl's еxpеrinkiеd pеаs and yеllow or grееn peasharaсtеrs сould Ье usеd in a variеty of , struсturеof dolphin groups to trасing al pollution. YaЬlokov сallеd thеsе dis>gypbеnes' and his Ьook Pbеnеtiсs is a ly of phеnеs саn Ье appliеd to almost 'logУ. ulation gеnеtiсist Nikolai Тimofееffgrее in 1965 at thе NovosiЬirsk Statе ion gеnеtiсs lеd him to thе phеnеtiс aplg miсroеvolutionaгyproсеssеsin natu' to Ьroadеr proЬlеms in Ьiogеography arе dеsсriЬеdin Phепеtiсs,as wеll as in rеd with Timofееff-Rеssovsky and сol:adеr in thе study of fluсtuating asymriс pattеrn that сan rеflесt a varietу of and hе was onе of thе first sсiеntists to .vation issuеs Ьy showing that pollution in skulls of gray sеals.Hе has also puЬ. , genеtiсsof whalеs and sеals and pioldividual identifiсation and thе traсing : yеars hе has Ьесomе onе of Russia's hе Russian pаrliamепt,was sсiеnсеadm b е r o f с o n s е г v а t i o no r g a n i z a t i o n s . usly influеntiaI in Russia and Еuropе, pеnsivе, morе dirесt molесular gеnеtiс :nеtiсaPproaсh has two parallеls. First, :сtion rесalls thе есologiсal gеnеtiсs of 3uеs.Indееd' many of thе ехamplеs of, in Ford's final еdition of Есologiсаl l study Ьiogеography, whiсh YaЬlokov

his wor! hаs Ьееn translatеd from thе Russian. Thе magnitudе of YaЬlokov's сontriЬutions еmеrgеs morе сlеarly whеn onе apprесiatеs thе сontеxt in whiсh hе workеd. FIе was a rеal gеnеtiсist doing rеal gеnеtiсs in thе Soviеt Union during thе Lysеnko еra, hе did not hаvе thе advantagеs that !Иеstеrn sсiеntistshavе in еquipment and rеsourсеs,and hе сhampioned еnvironmеntal issuеs in a plaсе and timе whеn it Was unpopular and еvеn dаngеrousto do so. в|вLloGRAPHY YaЬlokov,A. V. 1986.Phenеtiсs:Еuolutiсlп,Populаtioп,Trаit. М.J. Hall, tгans. Nеw York: СolumЬiа UnivеrsityPrеss. -D.s'. аnd I.T'

z Zoolo giсаI Philo sophу [ean-Baptistе Lamarсk) Zoologiсаl Pbilosophу philosophiе zoologiquе) was thе titlе of JеanBaptistе Lamarсk's most famous еxposition of his еvolutionary viеws (sее ..Jеan-BaptistеLamarсk'' in also thе alphaЬеtiсal еntry this volumе). PuЬlishеd in 1809, thе Ьook atrасkеd thе idеa of spесiеsсonstanсy.Yеt this was by no mеans Lamаrсk's only goal in this work. Не sought morе Ьгoadly to еxplain thе divеrsity of animal orgаnization and thе partiсular faсultiеs animаls dеrivеd fгom tlrе physiсаl struсturеsthеy pоssеssеd.In thе first part of thе work hе addrеssеd quеstions rеlating to natural history' with spесial attеntion to mаttеrs of animаl сlassifiсation, thе naturе of spесiеs, and thе influenсе of thе еnvironmеnt on aпimai strllсturеs. In thе sесond and third parts of thе work hе wеnt on to trеat thе physiсal сausеsof lifе and mоtion in thе simplеr animals and how it was that as animals Ьесamе morе сomplеx' thеy gainеd thе faсulty of fееling and thеn finally Ьесаmе сapaЬlе of intеlligеnt aсtion. This work rеflесtеd Lamarсk's imagе of himsеlf as morе than a сlassifiеrand сatalogеrof nаtuге produсtions. Hе dеfinеd his own rolе as thаt ..naturalist.philosophеr.'' of Lamarсk was forthright in rеjесting thе сreationist notion that all spесiеs had еxistеd from thе Ьеginning еxaсtly as onе found thеm in thе prеsеnt.Hе ..Naturе hаs produсеd all thе spесiеs of animals arguеd to thе сontrary that in suссеssion,Ьеginning with thе most impеrfесt or simplеst,and еnding hеr work with thе most pеrfесt,so as to сrеatе a gradually inсrеasingсomplеxity in thеir organization; thеsе animals havе sprеad at largе throughout all thе haЬitaЬlе гegions of thе globе, and еvеry spесiеs has dеrivеd from its еnvironmеnt thе haЬits that wе find in it and thе struсtural modifiсations whiсh oЬsеrvation shows us'' (Zoologiсаl Pbilosophу, |26). Aftеr intеrprеting thе аnimal sсalе as thе tеl11poгalordег in whiсh thе diЁ fеrеnt lеvеls of organization had Ьееn suссеssivеly produсеd, Lamarсk wеnt on to ехplain how thеsеdiffеrеntlеvеls of organization gavе risе to pаrtiсular faсultiеs (sее figurе). \(hеrеas еarliеr writеrs hаd arguеd whеthеr animals wеrе intеlligеnt' or whеthеr thеrе was suсh a thing as instinсt' Lamarсk offеrеd a naturalistiс еxplanation in whiсh thе differеnt faсrrltiеsof irritaЬility, thеn instinсt' and finally intеlligеnсе emеrgеd as animals of inсrеasing organiс сomplеxity wеrе suссеssivеly produсеd. In his aссount thе lеast pеrfесt animals wеrе stirrеd to aсtion only as thе rеsult оf ехсitations that саmе from sourсеs ехtеrnal to thеm. Thеy wеrе inсapablе of еxpеriеnсing sеnsations 9З2

Sеrра,l Vt

Ar Cir Mс

M,

T h е t r е еo f l i f еа s g i v е nl Atypiсally, it is to Ье rеa i n t е r p г е t а t i o nF .i г s t ,f o г ] of aсquirеdсhаraсtеrist upthrustof thе еvolutio Darwin (and othеrslikе l t h а t n е w I i f еf < l r mаs r ес t Ь е i n g .H е n с е .i f ( s а y )l i o youngег linе to produсеt

and likеwisе inсapаblес h i g h е r i n v е r t е b r а t еtsh a to givе thеm thе faсulty сitаtion of animal aсtioп Ьесamеthе Ьаsisfor il laсkеd сеrеbral hеmisp г h е y r е m a i n е di n с a p a Ь thе vеrtеЬratеs'Lamarс and thе mammals' wеr found, and еvеn thеsеa

ZoologiсalPhilosophy 9ЗЗ

.гABLЕAU Eеrvа,ntd m,antrerl,ori'ginесles dфrcns aninlq,цх,

Inflrsoiгеs. Pоlypе.s. Radiаiгеs.

Yеrs.

ltistе Lamarсk) >ologiqиe) was thе titlе of Jеantion of his еvolutionary viеws (sее tе Lamarсk'' in this volumе). Pub:a of spесies сonstanсy. Yеt this was ; work. Hе sought morе Ьroadly to ion and thе partiсular faсultiеs anis thеy possеssеd.In thе first part of l to natural history, with spесial atn' thе naturе of spесiеs, and thе in;trrrсtrrrеs.In thе sесond and third physiсal сarrsеsof lifе and motion in : as animals Ьесamе morе сomplеx, еn finally Ьесamе сapaЬlе of intеllik's imagе of himsеlf aS morе than a ions. Не dеfinеd his own rolе as that rе сrеationist notion that all spесiеs s onе found thеm in thе prеsеnt. He produсеd all thе spесiеsof animals npеrfесt or simplеst, and еnding hеr tе a gradually inсrеasing сomplехiry э sprеad at |ar1e throughout all thе y spесiеs has dеrivеd from its еnvil thе struсtural modifiсations whiсh 'sopbу,126). :hе tеmporal ordеr in whiсh thе difrссеssivеlyproduсеd, Lamarсk wеnt f organization gavе risе to partiсular .ritеrs had arguеd whеthеr аnimals .rсh a thing as instinсt, Lamarсk ofthе diffеrеnt faсultiеs of irritaЬility, rеrgеd as animals of inсгеasing orцсеd. In his aссount thе lеast pеrfесt . rеsult of еxсitations that сamе from rсapaЬlе of ехpеriеnсing sеnsations

Annеliitеs. Ciггhipёdes. Мollusщeв.

Insесtеs. Aгaсhдides. cгцgtaсёs.

Poissons. Reptiles. oiseauх. : Monotrёmes.

М, AmphЬЬs. М. Cёtacёs'

. M. oпguiсulds.

1'л.ongulёs.

Thе trее of lifе as givеn Ьy l,amarсk inhis Pbilosopbiе zoologiquе (1'809). Atypiсally, it is to Ьe rеad from top tо Ьottom. Сarе should bе takеn with its First, for l,amаrсk thе Ьrаnсhing(Ьroughton Ьy thе inhегitanсе intеrprеtation. was all rathеr inсidеntalto thе main progrеssivist сhаraсtеristiсs) of aсquirеd upthrustof thе еvolutionaryproсеss.Sесond,it should not Ье rеаd as with Darwin (аnd othеrslikе Haесkеl)as a trее of sharеddesсеnt.Lamarсk thought that nеw lifе forms arе сonstantly appеаring and thеn starting up thе сhain of Ьеing.Hеnсе, if (say)lions wеrе to go еxtinсt today it would Ье possiЬlеfor a youngеrlinе to produсеthеm.

and likеwisе inсapaЬlе of voluntary aсtion. It was only whеn onе сamе to thе highеr invеrtеЬratеs that onе found animals with a nеrvous systеm suffiсiеnt to givе thеm thе faсulty of fееling. At this point in thе sсalе thе sourсе of еx..intеrnal fееling'' сitation of animal aсtions Ьесamе intеrnalizеd, and a spесial Ьесamе thе Ьasis for instinсtivе aсtion. Howеvеr, insofar as thеsе animals laсkеd сеrеЬral hеmisphеrеs(thе organ of intеlligеnсе,in Lаmarсk's viеw), thеy rеmainеd inсapaЬlе of thinking and thus of any aсts of will. Only among thе vеrtеЬratеs,Lamarсk сlaimеd, and еvеn thеn pгimarily among thе Ьirds and thе mammals, wеrе intеlligеnt aсtion and thе faсulty of willing to Ье found, and еvеn thеsе animals aсtеd mostly hy instinсt.

9З4

Zoologiсal Philosophy Lamarсk's сontеmporariеs wеrе inсlinеd to trеat his Zoologiсаl Pbilosophу аs idlе spесulation.Thе work fаilеd to win thеm ovеr to thе idеа of orgaпiс еvolution. Today thе work stands out as a сlassiс of еvolutionary thought, although mоdеrn biologists do not еndorsе thе spесifiс mесhanismsthat Lamarсk сallеd upon to еxplain еvolutionary сhangе' B|вLIoGRAPHY Lаmаrt:hапd Еuolutioпаrу Burkhardt,R. !И.' Jr. \99 5 . Tbe Spirit of Sуstеtтl: Biologу. Nеw еd. CаmЬridgе,МA: Harvard UnivеrsityPrеss. Lапrarсk,J.-B. 1809. Philosophiezoologiquе,сluехpositiсlпdеs сoпsidёrаtioпs relаtiuеsd l,histoirепаtнrellеdesаnimаuх;Й Iа diuеrsitёdе lеur orgапisаtioпеt desfасultёsqu,ils еп obtiеппепt;а||хсаusеsphуsiquеsqui mаiпtiеппcпtеtl еuх qu'ils ехёсutепt;епfiп'а сellеsqui lа uiе еt doппепtliеu аuх ?flouL|emепs prodиiseпt,IеsunesIеsепtiment,еt IеsанtrеsI'intеlligеnсe de сеuх qui eп soпt douёs.2vols.Pirris:Dеntu. 1984.Zoologiсаl Philosophy.Нugh Еlliot, trans.Сhiсago:Univеrsityof -R.!ЙB. СhiсagоPrеss.

Contribui

Сolin Allеn (С.A.) is a pr Sсiеnсеand in thе Сognit He works on many issuе humаn aпimals,аnd has Мind (1997),ThеЕuolu

Gаrland Е' Allеn (G.Е.A Louis, whеrе hе tеасhеs of numеrous artiсlеs oЛ Thomas Hunt Мorgan, a Hе is сurrеntlyworking.

R o n A m u n d s o n( R . 4 . )i s Нilo. Hе is author of Тhougbt (2005).His rеs dеvеlopmеntаlЬiology.r ings) of disaЬility.

Miсhaеl F. Antolin is pro teасhеs population gеnе еntеringfrеshmento Post ation on еvolutionaryeс flowеring plants' prairiе r gion, and sосiеtyoffеr a 1

StеvanJ. Arnold (S.J.A.)is tilеs at Orеgon StаtеUnrr mеasuringsеleсtion'сomр tems. His othеr intеrestsi isolation, phеromonееvo

F r a n с i s с oJ . A y а l ai s U n i v Sсiеnсеsat thе Univеrsit сlеs and is authoror еdit of Sсiеnсеsand thе Amеr National Меdаl of Sсien M а n o f Е v o l u t i o n a r yB i o

nеd to trеat his ZoologiсаI Philosophу win thеm ovеr to thе idеa of organiс Lsa сlassiсof еvolutionary thought, alе thе spесifiсmесhanisms that Lamarсk angе.

уstеm:Lаmаrсk апd Еuolutioпаrу rrvardUnivеrsityPrеss. ae,ou ехpositioпdеs сoпsidёrаtions аuх: Й Iа diuеrsitёdс lеttrorgаnisаtionеt :аusеsphуsiquesqui mаiпtiеnnentеn еux qu'ils eхёсutепt;епfiп,Й cellesqui ; аutrеsl.intеlligепсе dе сеuх qui еп stlпt h Еlliot, trans.Сhiсago:Univеrsityof

-R.uИB.

Соntributors

Сolin Allеn (С.A.) is a profеssorin thе Departmеntof History and Philоsophyof Sсienсеand in thе Cognitive SсiеnсеProgram at Indiana Univеrsity' Bloomington. Hе works on mаny issuеsrеlatеd to thе еvolution of mind and сognition in non. human animals, and hаs сoautЬorеd and сoеdited Ьooks that inсludе Speciеsof Мind (1'997),Тhe Еuolution of Мiпd (1998), and Thе Сogпitiuе Animсtl (20О2). Garland Е. Allеn (G.Е.A.) is profеssorof biology at !ИashingtonUrriveгsityin St. Louis, whеrе he tеaсhesЬiology and histoгy of sсiеnсесourses.Hе is thе author of numеrous artiсlеs on the history of genеtiсs and еugеniсs, a Ьiography of Thomas Hunt Мorgan' аnd a Ьistory of thе lifе sсiеnсеsin thе twеntiеthсеntury. He is сurrently working on а history of gеnеtiсsin thе twеntiеth сentury. Ron Amundson (R.A.) is profеssorof philosophyаt thе Univеrsityоf Hawaii at Hilo. Hе is author of Thе Сhапgiпg Role of the Еmbrуo iп Еuolutioпаrу Thought (2005). His rеsеarсhfoсusеson thе rеlations Ьеtwееnеvolutionаry and developmеntalЬiology' and on Ьioеthiсal understandings(and misundеrstandings)of disaЬility. Мiсhaеl F. Antolin is profеssorof Ьiology at Сolorado StatеUnivеrsity,whегеhе tеaсhеspopulation gеnеtiсsаnd еvolutionary Ьiology to studеntsrаnging from еntеringfrеshmento postgraduatеs.His rеsеarсhfoсusеson еffесtsof spatialvariation on еvolutionаry eсology of organisms inсluding aphids' parasitoid wasps' flowеring plants' prairiе dogs, and plaguе. Thе сrossroads Ьеtwееnsсiеnсе,rеli gion, and soсiеty offеr a pоint of dееp fasсination аnd rеgular distraсtion. StеvanJ. Arnold (S.J.A.)is profеssorof zoology and сurаtor of amphiЬiansand rеptilеs at Orеgon StatеUnivеrsity.Hе is bеst known for his work оn tесhniquеsfor mеasuringsеlесtion'сomparinginhеritanсеmatriсеs,and сharaсtеrizingmatingsystеms. His othеr intеrеstsinсludе sеxual sеlесtionand its сonnесtionto Ьеhavioral isolation' pheromonееvolution,and tеstingmodеls of phenotypiсеvolution. FranсisсoJ. Ayala is Univеrsity Profеssorand Donаld Brеn Profеssorof Biologiсal Sсiеnсеsat thе Univеrsity of Сalifornia, Irvinе. Hе has puЬlishеd ovеr 900 artiсlesand is author or еditоr of 31 Ьooks.A mеmЬегof thе U.S. Nаtional Aсadеmy of Sсiеnсеsand the Amеriсan Philosophiсal Soсiеty,Ayalа reсеivеdthе 2001 U.S. National Меdal of Sсienсе.ТЬе Nezа York Times namеd him thе ..Rеnaissanсe Man of ЕvolutionaryBiology.''

9З5

9З6

Сontributors Jeffrеy L. Bada is a professor оf marinе сhеmistry аt thе Sсripps Institutiono{ oсеanography, Univеrsity of Сalifornia at San Diеgo. His primary rеsеаrсhdеals with thе origin of lifе on eаrth and еlsewhеrе.Hе is also involvеd with thе sеarсh for lifе Ьеyond еarth and is thе сhiеf sсiеntistfor thе Urеy Orgаniс and oхidant Dеtесtor instrumеnt on thе 2013 Еuropеan Spaсе Agеnсy ЕхoМаrs mission.

Riсhard !7. Burkhardt Jr Univеrsity of Illinois, UrЬa еvolutionary Ьiology inсlu< Biologу |977,1995) andI апd the Foипdiпg of Еthola

Сharlеs Baеr (С.B.) is an assistantprofеssorоf zoology at thе Universityof Florida' Hе is intеrеstedin nеmatodes(roundworms)as wеll as gеnеralissuеsin еvolutionаry Ьiology, inсluding lifе-historystrategiеsand thе evolution of mutation ratеs.

Joе Сain U.С.) is sеnior Univеrsity Сollegе London. ies, palaеontology,and nat

Ana Barahona (A.B.) is profеssorof history and philosophy of sсiеnсеat the National Univеrsity of Меxiсo. A pionееr in thе historiсal and philosophiсal studiеsof sсiеnсеin Mеxiсo sinсе 1980, shе foundеdthе arеa of Soсial Studiеsof Sсiеnсеand Teсhnоlogy in thе Faсulty of Sсiеnсеs.Shе has puЬlishеdwork on thе history of sсiеnсе in Мехiсo' gеnеtiсs' and еvolutionary Ьiology, as wеll as sсi. еnсе еduсation. Shе is thе prеsidеnt.еlесtof the Intеrnational Soсiеty for the History, Philosophy and Soсial Studiеs of Biology.

Еlof Axеl Сarlson (Е.A. D e p a r t m е n to f B i o с h е m i intеrеstsinсludе thе histor to soсiеty. Не is the auth Neithеr Gods Nor Bеаsтs (2008).

John Beatty (J.B.)teaсhеshistory and philosophy of sсiеnсе,and soсial and politiсal philosophy, in thе Dеpartmеntof Philosophy at thе Univеrsity of British Сolumbia in Vanсouvеr. Нis rеsеarсhfoсusеson thе thеorеtiсalfoundations, mеthodology, and soсiopоlitiсal dimеnsions of gеnеtiсs and еvolutionary Ьiology. Naomi Bесk (N.B.) rесеivеd hеr PhD from thе Univеrsity of Pаris 1 (Panth6onSorbonne) and is сurrеntly еmployеd as аssistantprofеssor at thе Univеrsity of Сhiсаgo. Shе wrotе on Spenсеr,sinfluеnсе in Franсе and Italy and now studiеs thе roiе of evolutionary idеas in Hayеk's frее-markеtthеoriеs. Мiсhaеl Bеnton is profеssor of vеrtеЬratеpalаеontology and formеr hеad of thе Dеpartment of Еarth Sсiеnсеs at thе University of Bristol. Hе is thе аuthor of many papеrs and Ьooks on vertеЬrаtе palaеontology and еvolution, inсluding lntroduсtioп to Pаlаеobiologу апd thе Fossil Rесord (200s). PеtеrJ. Bowlеr (P.J.B.)is profеssorof thе history of sсiеnсеat Quееn'sUnivеrsity' Bеlfast,Northеrn Irеland.Hе is thе author of sеvеralbooks on thе histоry of еvolution thеory' thе most rесеnt of whiсh is Мonkеу Triаls аnd corillа Sеrmoпs (2007\. С. Loring Braсe (С.L.B.) is profеssor of anthropology еmеritus at thе Univеrsity of Miсhigan and сurator of Ьiologiсal anthropology еmеritusat thе Univеrsityof Мiсhigan Мuseum оf Anthropology. Hе is thе author of many papеrs and sеvеral Ьooks on human еvolution,inсluding ,,Rасе''Is а Four-Lеttеr'Word(2005), whiсh shows thе aЬsеnсеof а Ьiologiсal Ьasis for thе сonсеPt of raсе. David J. Bullеr (D.J.B.) is Prеsidеntial Resеarсh Profеssor in thе Dеpartmеntof Philosоphy at Northеrn Illinois Univеrsity. Hе is the author of Аdаptiпg Мinds: Еuolutionаrу Psуchologу аnd thе PersisteпtQuest for Humаn Nаture (2005)and thе editor of Funсtioп, Selectioп,апd Desigп (1999).

Sсott P. Сarroll (S.P.С.)is Сеntеr for Population Biol Sсhool of IntеgrativеBiolo1 Сonseruаtioп Biologу: Еuo|

Brian Сharlеsworth(B.с.) i Biology at thе Univеrsity of ulation genеtiсs' moleсular ovеr 200 rеsеarсhpapеrsaI

DеЬoгah Сharlesworth is pr of ЕdinЬurgh. Shе works oI mosomеs'and is сoauthorс

Simon Сonway Morris (S.С Univеrsity of СamЬridge an in thе BurgessShalеand thе o f С r e а t i o п 'l 9 9 8 ) а n d i n е Yergеnсе (as ln Lifе's Solut deЬatеsand lесturеsand Ьr

Piеtro Сorsi (P.С.)is profеs is thе author of Ьooks on B

F. Сrow (J.F.С.)is Jamеs .Wisсonsin_Мadison. Hе hа а n d r е s е а r с hi n p o p u l a r i o authorеd thrеe Ьooks, inсiuс Genеtics Theorу 0970|.

Daniеl Dеnnеtt (D.D.) is U Philosophy, and сodirесto Univеrsity. Hе is thе auth

Сontributors nistry at thе Sсripps Institution of r Diеgo. His primary rеsеarсh dеals Hе is аlso involvеd with thе sеarсh for thе Urеy Oгganiс and Oxidant l а с е A g е n с yЕ х o M a г s m i s s i o n .

.W. Burkhardt Jг. (R.!f.B.) is profеssor of history еmеritus at thе Riсhard Univеrsity of Illinois, UrЬana-Сhaпrpaign. His writings rеlatеd to thе history of evolutionary Ьi
loology at thе Univеrsity of Florida. ; wеll as gеnerаlissuеsin еvolution. l rhе еvolurionof mutаrionratеs.

Joе Сain (J.С.) is sеnior lесturеr in history and philosophy of biology at Univеrsity Сollеgе London. He is an еxpert on thе history of еvolutionary studies,palaеontology,аnd nаtural history in Britain аnd the Unitеd Statеs.

and philosophy of sсiеnсе at the r thе historiсal and philosophiсal 'undеdthe arеa of Soсial Studiеsof 'сes.She has puЬlished work on thе .olutionaryЬioiogy, аs wеll as sсithе Intеrnational Soсiety for thе logy. phy of sсiеnсе'аnd soсial and po>sophyat thе Univеrsity of British )s on thе thеorеtiсalfoundations' rs of gеnеtiсs and еvolutionaгy

е Univеrsityof Paris 1 (Panth6onrant professorat thе Univеrsity of Frаnсе and Italy and now studiеs markеt theoriеs. rеontology and formеr head of thе ity of Bristol. He is the author of эntology and еvolution, inсluding Rесord (2008). ry of sсiеnсeat Quееn'sUniversity, еvеral Ьooks on thе history of evoэпkеу Тriаls аnd Gorillа Sermons

эpology еmеritus at thе Univеrsity ology emеritus at thе Univеrsity of е authof of many PaPегsand sеvlcе'' Is а Four-Lettеr Word (2005), for thе сonсеpt of raсe. :h Prоfеssor in thе Department of l is thе author of Аdаpting Мinds: rcst for Нumаn Nаtиrе (2005) and \999).

Еlof Aхеl Сarlson (Е.A.с.) is distinguishеd tеасhing profеssoг еmeritus, Dеpartmеnt of Bioсhеmistry and Cеll Biology, Stony Brook Univеrsity. His intеrеstsinсlude thе history of gеnеtiсsаnd еugеniсsand thе rеlation of sсiеnсе to soсiеty. Hе is thе author or еditor of 12 books, inсluding, most гесеntly, Nеither Gods Nor Bеаsts:Нoш SсiеnсeIs Сbапgittg.WЬo Wе Thiпk Wе Аrе (2008). Sсott P. Сaгroll (S.P.с.) is affiliatеdwith thе Departmеntof Еntomоlogy and Сеntеr for Population Biology at thе Univеrsity of Сalifornia, Dаvis' and thе Sсhool of IntеgrаtivеBiology at thе Univеrsityof Quееnsland.Hе is сoеditor оf СonsеruаtioltBiologу: Еuolutioп iп Асtioп (2008). Bгian Сharlеsworth(B.С.) is profеssorаnd hеad of thе Institutеof Еvоlutionary Biology at thе Univеrsity of ЕdinЬurgh. Нis сurrеnt resеarсhintеrestsаrе in population gеnetiсs'molесularevoluti
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Сontributors Еuolues (2003), Breаhiпg thе Spell: Rеligion аs а Nаturаl Pheпomeпon (20О6I, and many artiсles on mind' еvolution, and sсiеnсe. Adrian Dеsmond.(A.D') is Honorary Rеsеarсh Feiiow in thе Biology Department аt Univеrsity Collеgе London. His many Ьooks on Viсtorian еvolution inсlude Arcbеtуpеs аnd Аnсestors (1982), TЬe Politiсs of Еuolution (1989), andНuхlеу (1994-\997I, as wеll as two Ьooks сoаuthorеd with Jim Мoore, Dапuin (1991) and Dаrotlin'sSасrеd Саuse (2О09\. Мiсhaеl R. Diеtriсh (М.R.D.) is an assoсiatеprofеssor in thе Dеpаrtmеntof Biologiсal Sсienсеsat Dartmoцth Сollеge. Hе hаs writtеn a numЬеr of artiсlеson thе history of еvolutionary gеnеtiсsanJ molесцlar еvolution. Philip Donoghuе (P.D.) is a rеadеrin gеologyat thе Univеrsityof Bristol,Unitеd Kingdom. His main researсh intеrеsts,.. ,h" еmеrsenсe of еvolutionary novеl. tiеs and thе majоr еvolutionarytransitions. Gregory М. Еriсkson (G.М.Е.) is an assoсiatеprofеssor in thе Dеpаrtmеntof Biologiсal Sсienсе at Florida Statе Univеrsity. His rеsеarсh foсuses on thе lifеhistory еvolution and fееdingЬiomесhaniсsin nonavian and Ьasalavian dinosaurs. Zachary Еrnst (Z.Е.) is an assoсiatеprofеssor in thе Dеpartment of Phiiosophy аt thе Univеrsityof Мissouri_СolumЬiа.In addition rо йе philosophyof Ьiology, hе writеs on othеr suЬjесtsinсludinggamе theory аnd logiс. Dеan Falk (D.F.)is thе Halе G' Smith Profеssorof Anthropology at Florida Stаte Univеrsity.Shе has authorеdmany artiсlеsand a numЬе. or ьй, aЬoutvагious aspесtsof human еvolution. Alan Feduссia (A.F.) is S. K. Hеningеr ProfеssorЕmеritus and formеr сhairmаnof rhе Departmеntof Biology at thе Univеrsity of Nortlr Сarolina, Сhapеl Hill. Hе is thе author of numегouspаpеrson еvolutionaryЬiology, and his Ьooks inсludеT}e 'вoa, Аgе of Birds (l9s0) and Тhe origiп апсJЕuolutio, uf 0996, 1999). Maгtin Fiсhman (М.F.) is a professor of thе history of sсiеnсеat York Univегsity. Hе is thе author of many artiсlеs aпd four Ьooks, most rесеntlу Ап Еltlsiuе Viсtoriаn: The Еuolutioп of Atfrеd Rцssе!Wаllасе (z'ooц).In additron to thе his. tоry оfеvolutionarythought,his rеsеarсhintеrеstsiпсlцdе sсiеnсеstudiеsand thе сultuгаl history of Viсtоriаn sсiеnсе.

Сhaгles W. Fox (с.l07.F.)is а pгofеssoгin thе Dеpartmеnt of Еntomology at thе Univеrsityof Kеntuсky.Hе studiеsеvolutionaryесоlogy, primаrily of insесts'Hе is сoеditor of multiplе Ьooks in еvolutionaгy Ьiology, in.luding Еuo!иtioпаrу Есologу: Сoпcepts апd Саsе Studies (2001), Еuolutionаrу Gепеtics: Сoпсepts апd Саsе Studies(2006I, and СonsеruаtionBiologу: Еuolutiottin Асtioп(200s). Hе is alsо еxeсutivе еditor of thе journal Fuпсtioпаl Еcologу. Iгis Fгy (I.F.)tеaсhesthе history and philosophyof Ьiologyin the Dеpartmеntof Humanitiеs and Arts at the Tесhnion-IsrаelInstitutе ofЪсhnology. Shе is thе

аuthor o| Тhe Оrig Еmеrgeпсe of Lifе o

Jean Gayon (J.G.) i SorЬonne and a mеr аnd Teсhnique.Autt in history and philos mеtгy' gеnеral philсl thе lifе sсiеnсеs.

Niсholas W. Gillhаr Dеpаrtmеnt of Biolо undеrstаndinghow n gеnеsisof сhloroplаs (1978) and Оrgапеll

Brian Goodwin is a p Сollеgе' а сentrе of еxpiore сrеativееmеr

Bruсе S. Grant (B.S.G and Мary, whеre hе mеnt in 200l. Hе h: Wasps'Ьut sinсе 198З pеppеrеd moths, a fiе

JamеsHanken (J.H.)i Мusеum of Сomparar thе еvolutionarymorp аuthorеdnumerouspr ed Thе Skиll (199З|.B Еnсyсl
ShalaJ. Hankison is аr of Zoologу аt ohio Y selесtionаnd Ьеhаvio

John Barrеtt Неisеr (J. iсhthyology, aquatiс, ; days. He has studiеdfi: many sеas)from a va. dirесtor of thе Shoаlsl сoлtinuеs to tеасh Ьet сornеrsof thе еarth.

Jonathan Hodgе (J.Н.) the Univеrsity of Lееds аnсiеnt to prеsеnttimе Ьy Ashgatе PuЬlishing. сoeditеd with Grеgоry

Сontributors а Nаturаl Phenomепoп (2006), Lсe.

'еllow

in thе Biology Depаrtmеnt ; on Viсtorian evolution inсludе f Еuolution (1989), and Нuхleу with Jim Мoorе' Dаrъo,iп(1'991|

profеssor in thе Dеpartmеnt of s written a numЬеr of artiсlеs on Larеvolution. thе Univеrsity of Bristol, Unitеd mеrgenсеof еvolutionaгy novеl-

profеssor in thе Dеpartmеnt of lis rеsearсh foсuses on thе liferavianаnd Ьasаlаvian dinosаurs. n thе Departmеnt of Philosophy ition to the pЬilosophy of Ьiolo. heory and logiс. of Anthгopology at Floridа statе , n u m Ь е гo f Ь o o k sa Ь o u t v a r i o u s

]mеritus and formеr сhairman of orth Cаrolina, Сhapеl Hill. Hе is 'ology' and his Ьooks inс|ude The эn of Birds (1996,1999). lry of sсiеnсеat Yoгk Univеrsity. эoks, most reсеntly Аn Еlusiue се (2004),In addition to thе hists inсludе sсienсеstudiesand thе

еPartmеnt of Еntomology at thе есology' primarily of insесts.Hе эiology, inсluding Еuolutionаrу uolutionаrу Gепetiсs: Сoncepts >gу:Еuolution in Aсtioп (2008). cnаl Еcologу. of Ьiology in thе Dеpartmеnt of titutе of Teсhnology. Shе is the

author of The Оrigiп of Life: Муstеrу or Sсiеntifiс Problеm? (1997) and The Еmеrgeпceof Life сэпЕаrtb: А Historiсаl апd Sciепtifiс Оueruieш (2000). Jеan Gayon (J.G.) is profеssor of philosophy at Univеrsity Paris 1-Panthёon SorЬonnе and a mеmЬеr of thе Institutе for History аnd Philosophy of Sсiеnсе and Teсhniquе. Author of Dаrtuinism's Strugglefor Sиruiuаl (199s), his work is in history and philosophyof Ьiology,with spесialеmphasison 8еnetiсsand Ьiomеtry' gеnеralphilosophy of sсiеnсе,and sосial and еthiсal problеms raisеd Ьy the lifе sсiеnсеs. Niсholas !И. Gillham (N.!и.G.) is Jamеs B. Dukе Profеssor Еmеritus in thе Dеpаrtmеnt of Biology at Dukе Univеrsity. His rеsеarсh has Ьееn fосusеd on undеrstandinghow nuсlеar and organеllеgеnomеsintеrасt in сontrolling thе Ьiogеnеsisof сhloroplasts and mitoсhondria. Нis Ьooks inсludе Оrgаnеlle Hereditу (\978) and Оrgапеllе Geпеs апd Gеnomes (|994). Brian Goodwin is a profеssorof Ьiology tеaсhin8Holistiс Sсiеnсеat Sсhumaсhеr Сollеgе, a сеntrе of transformativеlеаrning for sustainaЬlеliving. His Ьooks explorесrеativееmеrgеnсеin Ьiologiсaland soсial сontеxts. BruсеS. Grant (B.S.G.)is profеssorof Ьiologyеmеritusat the Сollegеof !Иilliam and Маry, wherе hе taught gеnetiсsand еvolution for 33 yеаrs until his rеtirеmеnt in 2001. Hе has donе resеarсh witЬ Drosopbilа spectesand parasitoid wasps' Ьut sinсе 1983 his rеsеarсhhas foсusеdon thе еvolutionof melanism in peppеredmoths' a fiеld in whiсh hе rеmаins асtivе. JamеsHanken (J.H.) is Alехander Agassiz Profеssorof Zoo1ogуand dirесtor of thе Museum of Сomparative Zoo|ogу at Hаrvard Univеrsity. His rеsеarсhfoсusеson the еvolutionarymorphology, dеvеlopmеnt'and systematiсsof vеrtеЬrаtеs.Не hаs authorednumеrous professionaland popular аrtiсles,аnd with Brian Hаll сoedited The Skull (I99З). Bеginning in 2008, hе сhairs thе StееrinяСommittее of thе Еnсyсlopеdiaof Life. ShalaJ. Hankison is an assistаntprofessorof аnimal Ьеhаviorin thе Dеparrmеnт of Zoo1ogу at Ohio \йeslеyanUnivеrsity. Shе is intеrеstеdin thе rolе of sехual sеlесtionand Ьеhaviorin shapingеvolution. John Barrеtt Hеisеr (J.B.H.) has Ьееn assoсiatedwith Сornеll Univеrsity and its iсhthyology, aquatiс' and marinе Ьiology programs sinсе his graduatе sсhool days.Hе has studiеdfishеsand thеir haЬitatson еvеryсontinеntand oсean (plus mаny seas) from a variеty of platforms аnd land forms. For 15 yеars hе was dirесtorof thе ShoalsМarinе LaЬoratоry on Applеdorе Island,Mainе' wheгеhе сontinuеs to tеaсh Ьеtwееn Ьouts of lеading есo-еduсationаltours tо far-flung сornеrsof thе earth. Jonathan Hodgе (J.H.) is a senior fellow in history and philosophy of sсiеnсеаt thе Univеrsity of Lееds. Hе has writtеn on thеoгiеs of origins and spесiеsfrom anсlеntto Prеsеnttimеs.Тwo volumеsof his papеrsarе ЬеingpuЬlishеdin 2008 Ьy Ashgatе PuЬlishing.A rеvisеdеdition of his Саmbridgе Сompапion to Dаrшin, сoеditеdwith Grеgory Radiсk, wil| appеartn2ОО9.

9З9

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Сontributors Briаn Нollis (B.H.) is a grаduatеstudеntin thе Dеpartmеntof BiologiсalSсiеnсе at Florida Stаtе Univеrsity. His rеsеarсhintеrеstsinсludе tlrе study of sехual sеlесtiсlnand, Ьroadly,thе lеvеlsof sеlесtiondеЬatе. Tim J. Hordеr (T'J.H.) is a sеnior rеsеаrсh fеllоw at Jеsus С
Susan М. Kidwеll (S.iv1 Dеpartment of Gеophysr аt thе Univеrsity of Сhi thе fossil rесoгd and on Ьiology.

William С. Kimler (W.с.I N o r t h C а r o l i n аS r a t еU n i . a сorе faсulty mеmЬеr in in thе \йИ.М. Kесk Сеntе history of еvolutionaryidl tory' есology,and animal

J е г е m yK i r Ь y 1 J . K . )i s а s s i authorеdwоrks that trеat i n с I u d i n gа Ь о t - ' ko n A г i s t

Мanfrеd D. Lаubiсhlег(N of biology in thе Sсhooio itor of Froпt Еml-lrуolo Мodеliпg Biologу (with l Biologicаl Thеorу and thс

Antoniо Lazсano is profе: National Univегsity of Ме ovеr 750,000 сopiеs.Hе i Study of thе origins of Li

Jamеs G. Lеnnoх (J.G'L.) Univеrsitу of PittsЬurgh inсluding Аristotlе: Оп thс mеntary of Aгistotlе'ssеm

Riсhard Е. Lеnski (R.Е.L MiсroЬial Есology at Мiс Aсadеmy of Sсiеnсеs.Нis gеnomiс evolution in еxpс

'Wen-Hsiung Li (!И.-H.I-.)i a n d Е v o l u t i o nа t t h е U n i v lution of gеnегеgulatitln1 thе dеvеlopmеntof sratis

Curt Livеly (С.l-.)is а pro on prеdator-prеy.plаnt-p сontriЬurеdto thеorеtiсa sеxual rеproduсtion.

D a v i d N . L i v i n g s t o n еi s Quееn's Univеrsity'Bеlfa

Сoпtributors lpaftmеntof Biologiсal Sсiеnсе :s inсludе thе study of seхual rte. lllow at Jеsus Сollеgе in thе 'brуologу 0986) and has puЬimеntal rеsеarсh in thе еmЬry-

nеnt of Biologiсal Sсiеnсe at in еvolutionary gеnеtiсs' еsPе:volutionarvproсеss. е Dеpaгtmеntof Philosophy at rl Ьooks аnd numеrous Papеrs Ьiologiсalsystеmatiсs,and thе

1y аr NorthwеsrеrnUnivеrsiry. еs on human nаturе and is сo). еvoluti
еarсh faсulty member аt the s hаvе foсusеdon thе genеtiсs raсtions'thе еvolution of devеlthoг of Dаrшiпiаn Detес|iuеs: lmеs (2007). l thе Sсhool of Biology at thе kes a сomputаtionаlappгoaсh llution. Thе influеnсeof trans)nе Partiсularly aсtivе arеa of

thе Сеnrег for Сonsеrvаtion , е a r с hС е n t е ra t t h е U n i v е r s i t y olе of sехuаl sеlесtion in thе bilа.He has publishеdnumеr-

S u s а n М . K i d w е l l ( S . М . K . ) i s t h е W i l l i a m R a i n е y H a r p е r P r o f е s s o ri n t h е Dеpаrtmеntof Gеophysiсаl Sсiеnсеsand Сommittее on Еvolutionary Biology at tЬе Univеrsity of Сhiсago. Hеr rеsеarсh foсusеs on thе сomplеtеnеssof thе fossil rесord and on thе appliсation of skеlеtаl rеmains to сonsеrvation Ьiology. William С. Kimler (w.С'K.) is Alumni DistinguishеdUndеrgraduаteProfеssorаt North Саrolina StatеUnivеrsity,whеrеhе is аs assoсiаtеprоfessorof history and a сore faсulty mеmЬеr in thе Program on Sсiеnсе,Tесhnоlogy, and Soсiеty and in the W. М' Kесk Сеnter ftrr Behavioral Biology. His rеsеarсh intеrestsin thе histоryof еvolutionaryidеasliе in ninеtееr.rthand twentiеth-сеntury natural history, есology,and animal Ьеhavior. JеrеmyKirЬy (J.K.)is assistantprofеssorof philosophyat AlЬion Сo1lеgе.Hе has аuthоrеdworks that trеat suсh thеmсsas thе history of sсienсеand philosophy, inсluding a Ьook on Aristotlе,sсonсеption of сhangе. Маnfrеd D. LauЬiсhlеr(М.D'L.) is a profеssorof thеorеtiсаlЬiology and history of Ьiology in the Sсhоol of Lifе Sсienсеsat Aгizonа StatеUnivеrsity.Hе is сoеditor of From Еtnbrуologу to Еuo-Deuo (with Janе Маiеnsсhеin, 2ОО7) and Мodeliпg Biologу (with Gеrd Мiillеr, 2ОО7) and sеrvеs as assoсiatе еditor of Biologiсаl Thеorу and thе loltrпаI of ЕхperimeпtаI Zсэologу' Antonio Lazсano is profеssoгof origins of lifе at thе Еaсultad dе Сiеnсias of thе National Univеrsity of Mеxiсo. Hе is autlror of Оrigеп de lа Yidа, whiсh has sold ovеr 750,000 сopiеs.Hе is сurrеnt prеsidеntof thе IпtеrnаtionalSoсiеtyfor thе Study of the Origins of Lifе. JamеsG. Lеnnох (j.G.L') is profеssoгof Ьistory and philosophyof sсiеnсеat thе Univеrsity of PittsЬurgh. Не has writtеn ехtеnsivеly on Aristotlе and Darwin, inсluding Аristotle: Оn thе Pаrts of Аnimаls l_lV (200i ), а translation with сom. mеntaryof Aгistotlе'ssеminalwork' and Аristotle'sPhilosophу of Biologу (2001). Riсhard Е. Lеnski (R.Е.L.) is thе John A. Hannаh DistinguishеdPrоfеssorof Мiсгobiаl Есology аt Мiсhigan Statе Univеrsity and a mеmЬеr of thе National Aсadеmy of Sсiеnсеs.His rеsеarсh foсusеs on thе dyrramiсsof phеnorypiс and gеnomiсеvolutior-t in ехpеrimеntаlpopulаtionsof Ьaсtеriа. Wеn-Hsiung Li (w..H.L.) is Jamеs Watson Profеssorin thе Dеpartmеntof Есology and Еvolution at thе Univеrsity of Сhiсago. Нis rеsеarсhintеrеstsinсlude the еvolutiоn of gеnе rеgulation'gеne dupliсаtion and its еvolutionаryсonsеquеnсes,and thе dеvеlopmеntof statistiсalrnеthodsand сomputational tools for genomiс data. Сurt Livеly (С.L.) is а profеssorof Ьiсllogyat IndianaUnivеrsity.Hе hаs workеd intеraсtions.Hе has also on prеdator-рrеy,plant-pollinator,and hсrst-pаrasitе сontгiЬutеdto thеoгеtiсaland еmpiriсal studiеson thе еvolutionarystaЬilityof sехualrеproduсtion. David N. Livingstonе is profеssor of gеogгаphy and intеllесtual history at Quеen'sl-lnivеrsity,Bеlfast,Nоrthеrn lrеlаnd. Hе is thе author of many Ьooks

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Сontributors аnd artiсlеs on sсiеnсе and rеligion' most rесеntly Adаm's Аncestors: Rасе, Rеligion, апd thе Politics of Hиmап Оrigiпs (2008). Trudy Maсkay (T.М.) is a profеssorof gеnеtiсsat North Сarolina StatеUnivеrsity. Hеr researсh{oсusеson thе molесulаrgеnеtiсЬаsisоf variatiсlnfoг quаntitаtive traits. Janе Мaiensсhеin is Rеgents' Profеssоr, Prеsidеnt's Profеssor, and Parеnts Assoсiation Profеssor at Arizona Statе Univеrsity' whеrе shе dirесts thе Сеntеr for Biology and Sосiеty.Shе is thе author аnd еditor of morе than a dоzеn Ьooks and many artiсlеs, inсluding Defiпing Biologу 0986) and'\Yhosе Viеш of Lifе: Еmbrуos, Сloning, апd Stеm Сеlls (2ОО3). Lynn Мargulis (L.М.), Distinguished Univеrsity Profеssor, Dеpartnrеntof Gеosсienсes'Univеrsity of Маssaсhusеtts,Amherst' rесеivеd the Prеsidеntiаl Mеdal of Sсienсеfrom PrеsidentVilliam J. Сlinton ln \999, A memЬerof thе National Aсadеmy of Sсiеnсes shе invеstigatеsand puЬlishеs on еvolution (Ьv symЬiogenesis) and thе Gаia hypothеsis(of J. Е. Lovеloсk). Heпry M. МсHеnry is a profеssor of anthropology at thе Univеrsity of Саlifornia' Davis. Hе is thе аuthor of numеroцs studiеs of human fossil геmainsthat intеrprеtthе еvolutionaryrеlationshipsamong еxtinсt spесiеsand thе evolution of Ьipеdal walking, Ьrain-sizеinсrеasе,sехual dimorphism,аnd diеt. .!И. Daniеl МсShеa (D.!r.М.) is a palеoЬiologistin thе Biology Dеpartmеntat Duke Univеrsity. His resеаrсh has foсused thе аpparеnt trеnd in сomplеxity at thе largеst sсalе' in all of lifе, ovеr its еntirе history. He is сoаuthor of a rесеnt tеxtЬook, Philosophу of Biologу: А Сontemporаrу Iпtroduсtiсlп(20О8). Paolo Меnozzi (P.М.) is profеssorof есology аnd сhаirmаn of thе Dеpartmеntof ЕnvironmеntаlSсiеnсеsаt tЬе Univеrsityof Paгпа, Italy.Hе worked for пranyyеаrs on human population gеnеtiсsаnd is сoаuthor of Thе Нistorу апd Geogrаphуof Hиmаn Geпes (1,994).His сurrеnt rеsearсhfoсusеson gеnеtiсand есologiсal asPесtsof thе evolutionary Ьiсllogy of organisms as diffеrеnt аs zooplankton and forеst treеs. Мike Меstеrton-GiЬЬons(М.M.-G.) is a profеssorof mathematiсsat Florida Statе Univеrsity, whеrе hе dirесts rеsеarсhon сomplеx € ] amеs among humаns and othеr аnimals.Hе is thе author of two Ьooks on mathеmatiсalmodеlinяаnd numеrousartiсlеson еvolutionary8amе thеory.

Ь u r h i s p r i n с i p a lf o с u s , forсеsdriving сhangеslеa аs modеl systеms.onе ге ing rесomЬinаtionin faс

BеnjaminB. Normark (B sсiеnсеsand a mеmЬеro Ьiology at thе Univеrsity of armorеd sсalе insесts haplodiploidyand parth

Ronаld L. NumЬеrs (R.L М е d i с i n ea t r h еU n i v е r s are Dаrluinism Сolтlеstt prеsidеntof Ьoth thе H Сhurсh History' hе is сu and Philosophy of Sсiеnс

RoЬert olby (R.o.) is Dеpartment of thе Hrst PittsЬurgh.His work has lar biology.Hе has rесеn

Kеvin Padian (K.P.) is Musеum of Paleontology National Cеntеr for Sсrе

Diane B. Paul (D.B.P.)rs of Мassaсhusеtts,Boston Zoologу ar Hаrvard Univ issuеsin gеnetiсs.Hеr bс Prеsеnt (1995, \998) с Bioпediсine, апd thе Nа,

Patriсia M. Prinсеhousе philosophy of sсiеnсеa National Сеntеr for Sсiеп itiеs in the IntеliigеntDt Kitzmillеr u. Douеr Sсho tion and is сurrеntlywor

JamesМurray (J.М.) is prоfеssorof Ьiologyеmеritusat thе Univеrsityof Virginiа and somеtimеdirесtor of thе Мountain Lakе Biologiсаl Station. Hе is thе author of Geпеtic Diuеrsitу аnd Nаturаl Sеlection (1972| and many Papеrs on thе evo. lution and population Ьiology of polymorphiс land snails.

Мargarеt B. Ptaсеk is a Сlеmson Univеrsity.Неr populаtion gеnеtiсs,and that сontrol gеnеtiсdivеr Proсеssеsto loсаl adapta

Мohamed A. F. Noor (М.A.F.N.) is a profеssorof Ьiology at Duke Univеrsity. Hе is Ьroadly intеrеstеdin vаriousthеmеsin еvolutionirrygenеtiсsand gеnomiсs,

T o m R a y ( T . R . )i s p r o f е еnсe аt thе Univеrsityof

Сoпtributors ot|y Аdаm's Апсеstors: Rаcе, 8). ,loгthСaro]inаSratеUnivеrsity. ; i so f v a r i a r i o nf o r q u а n t i t a t i v е

lеnt's Profеssor, and Parеnts '' whеrе shе dirесts thе Centеr or of morе thаn a dozеn Ьooks '\X/hosе 985) and Уiеш сэfLifе:

ty Profеssoг, Dеpartment of erst, rесеived thе Prеsidential .!'999. ron irl A mеmЬеr of thе nd puЬlishеson еvolution (Ьy Lovеloсk). lpology at thе Univеrsity of гous studiеs of human fossil rips among еxtinсt spесiesand .еasе'sехual dimorphism, and

in the Biоlogy Departmеnt at ) p a r е n tt r е n d i n с o m p l е х i r ya t lry' Hе is сoauthor of a rесеnt ,у Introduсtion (2ОО8). сhairman of thе Dеpaгtmеnt of Italy.He workеd foг many yеars Тhe Historу апd Geogrаphу of цses on gеnetiс and есоlogiсal rs diffеrеnt as zooplankton аnd

Ьut his prinсipal foсus hаs Ьееn on thе gеnеtiсsundеrlying and еvolutionary forсеsdriving сhangеslеadingto spесiesformation, foсusingon Drosophilс speсiеs as modеl systеms.Onс rесurrеntthеmеin his resеarсhhas Ьеenthе rolе of restriсting rесomЬinаtionin fасilitatingspeсiеspersistеnсe. BеnjaminB. Normark (B.B.N.)is an assoсiatеpгofеssorof plant, soil' and inseсt sсiеnсеsand a mеmЬеrof thе grаduateprogram in organismiсand еvolutionаry Ьiology at the Univегsityof Мassaсhusеtts,Amhеrst. Hе studiеstЬe sуstеmаt,iсs of armored sсalе insесtsand thе еvolutiоn of unusual gеnetiсsystеmssuсh as haplodiploidyand pаrthеnogenеsis. Ronald L. NumЬеrs (R.L.N.) is Нilldalе Profсssorof thе History of Sсiеnсеand Меdiсinе at thе Univеrsity of Wisсonsin-Мadison. Among his many puЬliсations are Dаrcuiпism Сomes to Аmeriса (|998| and Тhе Сrеаtiottists(2006). A past pгеsidеntof Ьoth thе History of SсiеnсеSoсiеty and thе Amеriсan Soсiеty of Сhurсh Нistory' hе is сurrеntly prеsident of thе Intеrnational Union of History and Philosophyof Sсiеnсе. RoЬеrt olЬy (R.o.) is a historian of biology and rеsеarсh professor in thе Dеpаrtmеnt of thе History and Philosophy of Sсiеnсе at the University of PittsЬurgh'His woгk has Ьееnprinсipallyon thе history of gеnеtiсsand molесu. lаr Ьiologу.Hе has rесеntlyсomplеtеda Ьiographyof thе latе Dr. Franсis Сriсk. Kеvin Padiаn (K.P.) is profеssor of intеgrativе Ьiology аnd сurator in thе Мusеum of Palеontology'Univеrsityof California, Bеrkеlеy,аnd prеsidеntof thе National Сеnter for SсiеnсеЕdrrсation. Diаnе B. Paul (D.B'P.) is professorеmеritaof politiсal sсiеl.lсеat thе Univеrsity of Мassaсhusеtts'Boston' and геsеarсhassoсiаtеat thе Musеum of Сomparativе Zoo|ogу at Ilarvard Univеrsity. Shе has puЬlishеdwidеly on historiсal and poliсy issuеsin gеnеtiсs.Hеr Ьooks inсludе Сoпtrolliпg Нumап Неrеditу: 1865 to thе Рrеsепt (\995, 1998) and The Politiсs of Hеrеditу: Еssауs oп Еugепics, Biomediсinе, аnd tbe Nаture-Nurturе Debаtе (1998|.

sor of mathеmatiсsаt Florida ompleх gamеs among hurтans on mathеmatiсalmodеling and

Patriсia M. Pгinсеhousе(P.М.P') tеaсhеsеvolutionaryЬiology and history and .Wеstеrn philosophy of sсiеnсе at сasе Resеrvе Univеrsity. Shе reсеivеd thе National Сеnterfor SсiеnсеЕduсаtion's..Friеndof Dаrwin'' award foг hеr aсtivitiеs in thе Intеlligеnt Dеsign сontrovегsy and hеlpеd advisе thе lеgal tеam in Kitzmiller u. Douеr Sсbool Boаrd' Shе is thе author of many artiсles on evolution and is сurrеntly working on a Ьook' StepheпJау Gould's Vielu of Lifе.

tus аt thе Univеrsity of Virginia ogiсal Station.Hе is thе author .) and many papеrs on thе еvord snаils.

Margarеt B. Ptaсеk is a profеssor in thе Dеpartmеnt of Biologiсal Sсiеnсеs at Clеmson Univеrsity.Hеr intеrеstslie аt thе intеrsесtionof Ьеhaviorаlесology' population genеtiсs'arrd spесiation.Spесi6сa1ly,shе is intеrеstеdin proсеssеs that сontrol gеnеtiсdivеrgеnсеаmong populаtionsand thе сontriЬutionsof thеsе proсеssesto loсal аdaptationand spесiation.

o f Ь i o l o g yа t D u k е U n i v e r s i t y . rtionarygеnеtiсsаnd gеnomiсs,

Tom Ray (Т.R.) is pгсlfеssorof zoology аnd adjunсt profеssorof сomputеr sсiеnсе at thе Univеrsity of oklahoma. Hе has lеd rеsеarсh progrаms in tropiсаl

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Сontributors Ьiology and rain forеst сonsеrvationin Сosta Riсa and pionеerеdrеsеarсhon еvolutionin thе digital пrеdium.His сurrеntrеsеarсЬusеsgеnomiсdata to study the еvolutionof gеne fаmiliеsаnd to еxplorе new apPгoасhеsfor undеrstanding thе еvolutionand developmеntof thе human mind. David N. Rеzniсk (D.N.R.) is a profеssor of Ьiolсlgy at thе Univеrsity of Сalifornia' Rivеrsidе. Hе studiеsthе proсеssof naturаl sеlесtionand thе еvolution of сomplеx trаits.His primary study organismsаrе fisЬ in the family Рoесiliidae. Hе has publishеdovеr 100 rеsеarсhartiсlеsand rеviеwsin aсadеmiсjournаlsand еditеd volumеs аnd is сurrently writing А Rеаder's Guidе to thе origiп of Speсiеs. Riсhard A. Riсhards (R.A.R.) is assoсiatе profеssor of philosophy at the University of AlaЬama. Hе writеs on Darwin and pЬilosophiсaltopiсs in Ьiologiсal systеmatiсs. Robеrt J. Riсhards (R.J.R.) is thе Мorris FishЬеin Profеssorof History o{ Sсienсe at University of Сhiсago and professоr in thе departmеntsof history, philosophy, and psyсhology. Most rесеntly' hе is thе author of Тhe Trаgic Sепsе of Life: (2008). Еrпst Наeсkеl сlпtltbе Strugglеouеr Еуolutionаrу Th<'sнgb, Frеdrik Ronquist (F.R.) is profеssorand hеad of thе Dеpartmеntof Еntomology at thе Swedish Musеum of Natural Нistory. Hе is intеrеstеdin сomputationаl phylogеnеtiсs'partiсLllarlythе dеvеlopmеntof parsimоny mеthods for thе study of сoеvolution аnd biogеographyand, morе rесеntly' Bayеsian mеthods for phylogеnеtiсinfеrеnсе. Daniеl I. Rubеnstеin is thе Сlass of 1'877 Profеssorof Zoo1ogу,сhair of the Departmеnt of Есology and Еvоlutiorrary Biology, and dirесtor of thе Program iп Afriсan Studiеs at Prinсеton Univеrsity. Hе studiеs thе soсiаl Ьеhаviorof equids, thе movеmеnt есology of zеbrаs, and human-wildlifе intеrасtionsin Afriсa. .W.

Dаvid Rudgе (D.!f.R.) is an аssoсiatе profеssor in thе Departmеntof .W.еstеrn Biоlogiсal Sсiеnсеs at Мiсhigan University with a.sесondary appointmеnt in thе Маllinson Institutеfor SсiеnсеЕduсation. Hе is thе аuthor of sеvеrаl arriсlеson H. B. D. Kеttlewеll'sсlassiсinvеstigations of naturalsеlесtionin thе pеppеrеdmotlr, whiсh he has ехаmined from histoгiсal,philosophiсal,and sсiеnсе еduсationPегsPесtivеs. Niсolаas A. Rupkе (N.A.R.) is a profеssorof thе history of sсiеnсeand dirесtor of thе Institutе for thе Нistоry of Sсiеnсе at Gottingеn Univеrsity. Among his publiсationsis a monographon Riсhard owеn (|994 nеw еdition,2008). Miсhaеl Rusе (М.R.) is thе Luсylе T' WerkmеistеrProfessorof Philosophyand dirесtor of thе Рrogrаm in thе History and Philosophy of Sсiеnсeat Florida Statе Univеrsity. Hе is thе аuthor of many Ьooks on еvolutionary thеmеs,inсluding Tbe Dаruliпiап Reuolution: Sciепсe Red iп Tooth апd Сlаш (1979|, Мoпаd to Мап: The Сonсеpt of Progrеss iп Еuolutioпаrу Biologу 0996|, and Сап а Dаrltliniаn Bе а Сhristiаn? 2001\'

Doriсln Sagan (D.Sa.)'pa many artiсlеs' Poеms' anс inсludе Notеs froш thе H Humаn Iпtelligeпcе(wtth. Тb еrtпсldупа m i сs а пd I.ifе , ain t u г е 'a n d p h i l o s o p h ym hе gгaduatedwith а BA in

Jamеs William Sсhopf (J.! Dеpartmеnt of Еarth and S Study of Еvolution and th Angеlеs.A memЬеr of thе author' his intеrеstsfoсus.

Еugeniе С. Sсott is ехeс Еduсatiоn (NСSЕ) in oak] zatiol' NСSЕ promotеs еv thе author of Еuolutioп t сoеditor (with Glеnn Branс Is Wrсlпg for Оltr Sсhools

Jon Sеgеr(J.S.)is a profеs works mainly on thе еvоlut whosе simplе populationh unusually wеll dеfinеdеvot

U l l i с a S е g е r s t r a l(еU . S . )i s a Sсholars Program at thе Ill tеn on issuеsat thе intеrsе inсludе Dеfепders of thе Т сoming Nаtиre's Оrасlе: А

David Sеpkoski (D.Sе.)rs l North Сarоlina, Wilmingtt еvolutionary thеory. Hе is Reuolutioп: Еssays oп thе l i n g a Ь o o k a Ь o u tt h е h i s г o

Н. BradlеyShaffеr(H'B.s.)i works on thе evolutionaryt ians and rеptilеs.Reсеnt res amphibians аnd rеptilеsin ( frеshwatеrtшrrlеsand torto vation 8еnеtiсsof еndаnge

Daniеl SimЬеrloff(D.Si.)is Studiеs аnd dirесtor of tlre Tеnnеssее.Hе is an еvolut i e s а г а n g еo f r o p i с st h а t i n tiЬility of сommunitiеsаnd

Сoпtributors a and Pionееrеd rеsеarсh on lh uses gеnomiс datа to study pproaсhеs for undеrstanding

'iology at the Univеrsity of гаl sеlесtionand thе еvolution fish in the family Poeсiliidaе. еws in aсаdеmiсjournals and er's Gцidе to tbe origin of

Ъssor of philоsophy at thе ilosophiсaltopiсs in Ьiologiсal

Dorion Sagan (D.Sa.),partnеr of Scieпсешriters,Ьas authored or сoauthorеd many aftiсlеs,poеms' and ovеr l5 Ьooks trаnslаtеdinto l1 lаnguagеs.Thеsе inсludе I'lotesfrom thе Holoсепе (2007|, Up from Drаgс'lns:Thе Еuolutiс>пof Humап lntelligеnce (with John Skoylеs, 2002I, aod lnto thе Сool: Епergу Floou, Thеrmodуlсlmiсs аlld Lifе (witЬ Еriс D. Sсhnеidеr,200.'). Hе studiеd art' litеra. turе,and philosophy'mainly at thе Univеrsityof Мassaсhusеtts,Amhеrst,wherе hе graduatеdwith a BA in history. .!filliam Sсhopf (J.!7.s')is distinguishеdprofеssoгof palеoЬiologyin the Jamеs Dеpагtmentof Еarth and SpaсеSсiеnсеsаnd Dirесtor of thе IGPP Сеntеr for the Study сlf Еvolution аnd thе oгigin of Lifе at thе Univегsitу of Сaliforrriа,L
rofеssoгof History of Sсiеnсе ;mеntsof history, philosophy, of Thе Trаgiс Sense of Life: Thought (2008).

Еugеniе С. Sсott is ехесutivе dirесtor of thе National Сеnter for Sсiеnсе Еduсаtion (NсsЕ) in oakland' Сalifornia. A not.for.profitmеmЬеrshiporgаnization' NСSЕ promotеsеvolutionеduсation.Sсott,a pЬysiсalаnthropоlogist'is thе author o| Еuolution us. Сrеаtionism: Ап lntrсlduсtion (2004, 2008) and сoеditor (with Glеnn Branсh) of Nor in Оur Сlаssrсloms:Whу Iпtеlligent Dеsign Is Wrong for Our Schools (2006).

е Departmеnt of Еntomology s interеstеdin сomputational ;imony mеthods for thе study еntly, Bayеsiаn mеthods for

Jon Sеgеr (J.S.)is a proiеssor of Ьiology at thе Univеrsity of Utah. Hе сurrеntly works mainly on thе еvolutionaгygеnеtiсsof whale liсе (Amphipoda,Сyamidaе), whosе simplе population historiеs and есologiеsallow thеm to Ье intегprеtеdаs unusuallywеll dеfinеdеvolutionaryеxpеrimеnts.

sor of Zoology, сhair of thе and direсtor of thе Program :udiesthе soсial Ьehavior of r m а n - w i l d l i f еi n t е г а с t i o n si n

Ulliсa Sеgеrstrаlе(U.S.)is a professorof soсiology and thе dirесtor of thе Сamras SсholаrsProgram at thе Illinois Institutеof Tесhnology,Сhiсagо. Shе has writtеn on issuеsаt the intеrsесtionof sсienсе,valuеs,and human nature.Hеr Ьосrks inсlude Dеfепdеrs of the Truth: Tbе Soсiobiologу Dеbаtе (2000) and thе forthсoming Nаture's orаcle: А Lifе of \(. D. Hаmiltoп.

.еssor in thе Department of гy with a sесondагyappointon. He is thе authoг of sеvеr. 'ons of natural sеlесtionin thе oriсal, philosophiсal,аnd sсi-

ristoryof sс,iеnсе аnd direсtoг :ingen Univеrsity. Among his )94; nеw еdition, 2008). . Profеssor of Philosophy and >hyof Sсiеnсеat Florida Statе lolutionary thеmes,inсluding аnd Сlаul \|979), Мonаd to Biologу 0996\, and Сап а

David Sеpkoski (D.Sе.)is an аssistantprofеssorof history аt thе Univеrsity of .Wilmington. North Сarolina, Hе spесializеsin thе history of palеontologyаnd is еvolutionary thеory. Hе еditor, with Мiсhаеl Rusе, of Тhe Pаleobiologiсаl Rеuolution: Еssауs oп tbе Historу of Rеcеnt Pаlеoпtologу Q0О9) and hе is writing a book aЬout thе history of palеоЬiоlogy. H. Bradlеy Shаffеr(Н.B.s.) is a pгofеssoгat thе Univеrsity of Сalifornia, Davis. Нe works on thе еvolutionаryЬiology, есology,and сonsеrvationЬiology of amphib. iаns and rеptilеs.Rесеnt rеsеarсhproiесtsinсludе сompaгativеphylogеographyof amphiЬiansand rеptilеsin Сalifornia аnd thе сеntгalUnitеd statеs' systеmatiсsof freshwаtеrturtlеs and tоrtoisesЬoth gloЬally and in еastеrnAustralia, and сonsеr. vation gеnеtiсsof еndangerеdСalifornia аmphiЬiаns and геptilеs. Daniеl SimЬеrloff(D.Si.)is thе Nanсy Gorе Hungеr Profеssorof Еnvironmеntal Studiеsand dirесtorof thе Institutеfоr BiologiсtrlInvаsionsat thе Univеrsityof Tеnnеssее. Hе is an еvolutionaryесologistand сonsеrvationЬiologistwho studiеs a гangеof topiсs that inсludеsthе есologvof invasivеspесiеsand thе susсеptiЬility of сommunitiеsand есosystеmsto invasiorrЬy ехotiсs.

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Сoпtributors RoЬеrt A. SkippеrJr. (R.A.s.)is assoсiatеprofеssorof philosоphyand аifiliаteof thе Сеntеr for ЕnvironmеntаlStudiеsаt thе Univеrsity oi Сinсinnаti. His work foсusеsmainly on thе сonсеptuаland historiсalfoundationsof еvolutiоnarygе. nеtiсs,partiсularlythе dynamiсsof сontrovеrsiеswithin thе fiеld. Vаssiliki Bеtty Smoсovitis (V.B.S.)is profеssorof thе histоry of sсiеnсеin thе Dеpartmеntsof Zoo|ogу and Histоry аt the Univегsiryof Floridа. Slrе is also аifiliаtеd witЬ thе Bоtany dеpartmеnt.Slrе is tЬе autlror of Unifуiпg Biok.lgу:Tbе Еu o lutionаrу Sуl tth esi s аnd Еu сll ltti rlnаrу B io logу 09 96). Trishа Spеars (T.S.) has hеld rеsеarсh and instruсtional positions in the Dеpartmеnt of Biologiсаl Sсiеnсеаt Floridа Statе Urrivеrsitysinсе 1989. Her rеsеarсhintеrеstis irr thе arеa of сrustaсеanmolесulагsystеmatiсsаnd еvсllution, whеrеЬy DNA еvidеnсеis usеd to invеstigatееvolutionаryrеlationshipsamong сгustaсеans'as wеll аs thе gеnеtiсvariation among populationsof сrustaсеan spесiеs.Shе is аlso a past prеsidеntof thе СrustaсеanSoсiеty,an intеrnational soсiеtyof сarсinologists. Kinr Stеrеlnyis a protЪssorof philсlsоphyat thе AustraliаnNational Univеrsity and thе Viсtor.ia University of Wеllingron. Hе has writtеn еxtеnsivеlyon thе intеrsесtionof pЬilсlsophyand thе lifе sсiеnсеs,with а partiсularintегеstin thе геlationshipЬеtwееnmiсroеvolutionand maсroеvoiution,and thе еvolutionof humаn сognition and Ьеhavior. Jarnеs Е. Striсk (J.Е.S.)is assoсiаtеprofеssorin thе Dеp:rrtmеntof Еartl-rand Еnvironmеnt and сhair of thе Pгсlgramin Sсiеrrсе,TесЬnology аnd Soсiеtyat Frаnklin аnd М.rrshall Сollegе in Lanсаstеr,Pеnnsvivaniа.originally trаinеdin miсroЬiology,and later in history of sсiеnсе,hе has publishеdехtensivеlyon thе history of ideas and еxpеrimеntsaЬout thе origin of lifе, inсluding S1lаrksof Life: Dаrшiпism апd thе Victoriап Dеbаtеs ouеr SpoпtапeousGепеrаtiсп (20О0I and' with Stеvеn Diсk, Тhe Liuiпg Uпiuеrsе: |'IАSA апd tbе Dеuеlopmепt of Аstrobiobgу' (2004). Сhаrlеs Е. Taylor (с.Е.T.) is profеssorof есologyаnd еvоlutionaryЬiologyat thе Univеrsityоf Сalifornia' L,osAngеlеs.Hе dirесtstwo rеsеarсhprograms,onе in аrtifiсial lifе and thе еvolutionof sеlf-organizationand еmеrgеntЬеhаviorsand onе on population gеnomiсsof Апophеlеsgаmbiае аnd thе faсtоrs that detеr. гatеsof malirriа,r'rsing сomputеrmodеlsand пrinеlrlсalvагiаtionin transmissiсrn еmpiriсal studiеs. Rсlgеr D. K. Thomas (R.D.K.T) is tЬе John !Иilliаmson Nеvin Profеssorof Не is a Gеosсiеnсеsat Franklin аnd Marshаll Сollеgеin Lanсаstеr,Pennsylvaniа. palеontologist'witlr irrtеrеstsin funсtionzrland ссlnstruсtionalmorphology'the dеsign of aniпrаl skеlеtсlns,evolutionаrythеory, and thе history of sсiеnсе.His assеssmеntof StеphеnJay Gсluld's сontriЬutionsto furrсtionalmorphology сan Ье fоund in thе сollесtion Stepheпlау Gould: Rеfleсtionsсln His Viеш of Lifе (2009), Josеph Travis (J.T.) is thе RoЬеrt O. l-awton DistinguishесlProfеssorof Biologiсal Sсiеnсеand dеan of thе Сollеgеоf Arts сk Sсiеnсеsаt Florida StatеUnivеrsity.Нis

rеsеаrсhin еvolutionаryb nеtiсs, in partiсular ех21ш tion in thе lifе histoгiеsal

Еdgar Е. Vallеjo (Е.Е.V.) Teсnologiсo y dе Еstudiо Не is the author of mаn gеnеtiсprogramming,еv еvolutionof languagе.

David B. Wakе (D.B.!f.) Мusеum of VеrtеЬratеZt lutionary Ьiologist,hе ha сiаlly salаmandеrs'using есologiсal'аnd sу'stеma is high risk of еxrinсtit'lll'

.!Иеst.Еbеrh Мary Janе Tropiсаl RеsеarсhInstitц lution of soсiаl insесts,s< thе author of DеuеloРm

Paul B. Wignall (P.8.!f.) thе Institutеof Gеologiс Hе is thе author of many еs, еspесiallythе еnd.Pe

David Sloan l7ilson (D BinghamtonUniversity( thеory to all aspесtsof h numеrousЬooks, inсlud 'Wау We Тht Сhапgе thе oning thе thеory of mu еvolvеat all lеvеlsof thе

.!7insor (М.P.W Mary Р. Philosophy of Sсiеnсеan Stаrfish'!ellуflsh,апd the ally symmеtriсаlanimais history of Harvard's Мur Shаpe of Nаture (1'991)

Gгеgоry A. Wray is r Е v o l u t i о n а r yG е n o m i с s еvolutionof dеvеlopпlе

Jason Zinsеr (J.Z.)is a vt of North Florida. His di сonсept of сontingеnсyr

Сoпtributors cr of philos
A u s t r а | i а nN а t i о n a l U n i v е r s i t y has writtеn ехtеnsivеly on thе vith a partiсulаr intеrеst in thе :volution,and thе еvolution of

thе Dеpartmеnt of Еarth and се. ТесhnoIogyand Soсiеty аt nsylvania.originаlly trainеd in as puЬlishеdextеnsivеlyon thе ;in of lifе' inсluding Spаrks of |pontапeousG еnеrаtioп(2000) .АSА апd thе Dеuelopment of

and evolutionaryЬiology at the two rеsеaгсhprograms' onе in ln and еmеrgеnt Ьеhaviors аnd ,iае and the faсtors that dеtеrгia,using сomputеrmodels and

Иilliamson Nеvin Profеssor of -anсastеr'Pеnnsylvania.He is a Ionstruсtionalmorphology, thе and the history of sсiеnсе. His l funсtional morphology саn Ье oпs on His Уiеш of Lfe (2009). rguishеdProfеssorof Biologiсal at Florida StateUnivеrsity. His

rеsеarсhin еvolutionary Ьiology follows thе traditional paradigm of есologiсalgеnеtiсs,in partiсular ехamining thе сausеsаnd сonsеquеnсеsof population variation in thе lifе historiеs and mating systеmsof livеЬеaringfishеs. Еdgar Е. Vallеjo (Е.Е.V.) is an assoсiateprofеssorсlf сomputеr sсiеnсеat Instituto Tесnologiсo y de Еstudios Supеriorеsdе Мontеrrеy' Сampus Еstado dе Меxiсo. Hе is thе author of many pаpеrs on еvolutionary сomputing thеmеs' inсluding gеnеtiс programming' еvolutionary roЬotiсs, and simulations on thе origin and еvolutionof languagе. David B. !Иakе (D.B.Iй/.)is a profеssor of intеgrаtivеЬiology and сurator in thе Мusеum of VеrtеЬrаtеZoo|ogу at thе Univеrsity of Сalifornia, Bеrkеlеy.An еvolutionaryЬiologist'hе has puЬlishеdmany rеsеarсhpapеrson amphiЬians'еsPесially salamandеrs,using morphologiсal, dеvelopmеntal' genеtiс' phylogenеtiс, есologiсal,and systematiсdatа. Thе plight of amphiЬians' many of whiсh arе at high risk of еxtinсtion,is а сurrеntfoсus. .Wеst-ЕЬеrhard Мary Janе (М.J.W.-Е.) is sеnior sсiеntist at thе Smithsonian Tropiсal Rеsеarсh Institutе.Shе has writtеn ехtеnsivеlyon thе Ьеhavior аnd еvolution of soсial insесts,sехual sеlесtion,and spесiation-rеlatеddivergеnсеand is thе author of DeuеlopmeпtаlPlаstiсitу аnd Еuolutioп (2003). Paul B. !Иignall (P.B.!и.)is a profеssor of palеoеnvironmеntsand the dirесtor of thе Institutеof Gеologiсal Sсienсеsat thе Univеrsity of Lееds, Unitеd Kingdom. Hе is thе author of mаny pаpеrson thе thеmеof mass еxtinсtionsand thеir сausе s .е s p е с i а l l yt h е е n d - P е r m i e n еvеnt. David Sloаn Wilsоn (D.s.\Jr.) is profеssоr of Ьiology and anthropology at Binghamton Univеrsity (StatеUnivеrsity of Nеw York). Hе appliеs evolutionary thеory to all aspесtsof humanity in addition to thе rеst of lifе. Hе is author of numеrous Ьooks, inсluding Еuolu.tionfor Еuеrуoпe: Hoш Dаrcuin's Thеorу Саn Сhаngе thе'Wау-Wе Тhink аbout Оur Liuеs (2О07).Hе is known for сhampioning thе thеory of multilеvеl sеlесtion'whiсh еxplains how adaptationsсan еvolvеat аll lеvеlsof thе Ьiologiсalhiеraгсhy,from gеnеsto есosystеms. Mary P. \Winsor(М.P.!и.) is emeritaprofеssorin thе Institutеfor the History and Philosophy of Sсiеnсе and Teсhnology at thе Univеrsity of Toгonto. Hеr Ьook Stаrfish,Jellуfish,аnd tbе order of Life (1976) dеsсriЬеsthе сlassifiсationof radi. ally symmеtriсаlanimals in thе first half of thе ninеtееnthсеntuгy' Shе traсеs the history of Harvard's Мusеum of Сomparative Zoo|ogу in hеr book Rеаding thе Shаpе of Nаturе (1991)' Grеgory A. Wray is a prсlfessor of Ьiology and dirесtor of thе Сеntеr for Еvolutionary Gеnomiсs at Dukе Univегsity. His rеsеarсh interеsts inсludе thе еvolutionof dеvelopmеnt'gеnomеs'and gеnеnеtworks. JasonZinsеr (J.Z.)is a visitingassistantprofеssorof philosophyat thе Univеrsity of North Florida. His dissеrtatiоnсentеrеd on thеorеtiсal morphology and thе сonсеpt оf сontingеnсy in еvolutiоnary thеory.

947

948 Сontributors Marlenе Zuk (М'Z.) is a profеssor of Ьiolоgy and thе assoсiatеviсе provost for faсulty еquity and divеrsity at thе Univеrsity of Сalifornia' Riversidе. Shе studiеs sеxual sеlесtionand host-parasitееvolution in a variеty of organisms,and did hег PhD with !7. D. Hamilton at thе Univеrsity of Мiсhigan.

Illustration

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lnd thе assoсiatеviсе provost for California' Rivеrsidе.Shе studiеs variety of organisms,and did hеr Miсhisan.

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Pagе9: By pегmissionof ЕrrglishHеritagе. Pagе t 0: By pеrnrissionof еstаtеof John Сhanсеllor. P a g е l 2 ' b o t t o m :M S . D A R 1 2 1 , p . 3 6 , d r a r , v nЬ y С h a r l е s D а r w i n , а n d r е p r o duсеd Ьy kind pеrmissiоnof thе Syndiсsof СаmЬridgеLInivеrsityLiЬrarl'. Pagе26: Pl-rotoЬy Josеph Сain; usеdwith pеrrnission. Pagе 3З: From Dtlbzhdnskу's Gutеtiсs of |'lаtrtrаlPсlpиlсltioпs,еd. R. С. Lеwontin еt al. (Nеw York: СolumЬiа Univеrsity Prеss,1981);Ьy pеrmissionсlf thе puЬlishеrand thе еstatе
e49

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[llustrаtiottСrеdits Page492: By pеrrnissiсln оf thе author' Gary С. B. Poorе' аnd Мusеum Viсtoriа. Pagе .520:Rеdrаwn with pеrrтissionfrom Haydеn-МсNеil PuЬlislring,Inс. Page 527: Рhoto Ьy Jarnro Нalopainеn;usеdwith pеrmission. Pagе 556: By pегmissionof SpringerSсiеnсе+ BusinеssМеdia. Pаgе 596: Plroto LryЕdrvаrd G. R. Rusе;usеdwith pеrmissiсln'

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AЬеlе,L. G.,491' AЬrams, Stеvе,387 Aсаdеmiс F.rееdomAсts Aсritarсhs, 782-784 Adаgltаtiorr,105-1З0; B and Sсhmidt-Niеlsеnl соmplех tгaits сontro d е f i n е d ,l 0 5 - 1 0 7 ; d е r 1 09_1 1 1; еr,olutiona еasе, 2B4_285, 289-2 l 0 8 - 1 0 9 ; f i l t u r еs t u d miсroеvоlution vегsu tion, |26_129; nсln-in tion, |24-126; pеrfесt 1 1 4 _ 1 1 . 5р; h i l o s o p h y t l r o u g h t , 3 l 3 - З l 4 ;p s 558; raw mаtеria|аva r,еrsy,1 1З_114; rесon 1 1 1_11 3; soсiеty and, Аdаptаtklп апd N"ttнrаl Williams), 403-404,6 921 Adaptivе lаndsсapе mеt.

860f

Adaptivе plastiсitt..See Р tiсity Аdaptivе rаdiation, 793' AеroЬiс оrganisms, first с Afriсa: dispегsionfrom, , 695_697; Lеakеy and' А'fzaa|,Ahmеd, 361' 362 Agaпrospесiеs,4l [l Agassiz' Jеаn Louis Rodс 441, 50-i,594,677,6f Аgе сlf Маmmаls iп Еurс' Nсlrtlt Аnrcriса, Thе (( Aging. Seс Sеnеsсеnсе

i. B. Poorе,аnd Мusеum Viсtoria' dеn-MсNеil Publishing,Inс. .ith pеrmissiorr. BusinеssMеdia. лrithpеrmission.

Indеx

гmission. r of Natural History. arativеZoo|ogу,Harvard Univеr-

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od faith, without stlссеss'tO traсе s сlaimed,it will Ье aсknowlеdgеd еrs Ltd.: Naturе PuЬlishingGroup. ahassее'our artist' for working so rawingmаny and making surе that

No/e: Pаgе numЬеrs in Ьold indiсаtе alphаЬеtiсalеntriеs.Pagе nuпrЬеrsfоllowеd Ьy / and r indiсatе figurеsand taЬlеs. Agnosis, 651 A Ь е l е ,L . G . , 4 9 1 Ahourrtа, DjimdoumаЬауe, 263 AЬrams, Stеvе,387 AlЬеrсh, P,, 21.7f Aсadеmiс F.rееdom Aсts' 394 Alехаndеr, Riсlrard D., 24I, 406_407 Aсгitаrсlrs, 782-784 Allmеrs, Hеrmann, 623 Adaptаtion, l05_130; Bartholomеw Allornothетs,643 аnd Sсlrmidt-Niеlsеn and, 443-444; Allоpatriс spесiation,94, 725 сomplех traits сontrovеrsy, l 1 5- 124; Altеrnativе dеvelopmеrrtаlroutеs, d е 6 n е d ' I0 5 _ l 0 7 l d е n t t r n ь t r l г i t l n s . 22--228 109-1\1; еvolutionary Ьiology of disAltеrnativе mаtillg pattеrns,247 -2.48 еаsе,284_285, 289-29 2; еxаmplеs, Altruism, 4o7 -470i аdаptаtion irnd, 108-109; futurе studу, 12.9-1З0; 125; Ьiologiсаl and psyсhologiсal, t-niсroеvolrrtionvеfstls nraсroеvolu408,4I0; population Ьiology and, tion, |26_ |29; rron-individual sеlес. 865; soсial Ьеhavior and,239,244' rkл. |2-4_126; pеr{есtiсlnсontrovеrsу' 347-з42' 629-630 1 14-l 15; philosophy of еvolr.rtionary A l v а r e z ,L u i s ' 4 1 1 ' 8 2 5 thought, 3 13-314; psусhologiсаl, Alvаrеz, Y/altеr, 4||4|2' 716, 825 558; raw пratеri;rlavailаЬility сontroАmеriсоtl Аddrеssеs(T. H' Huхlеy), 650 v е r s у , , l1 3 - 1 1 4 ; г e с o l l s t r u с t i n g , Amеriсаn Assoсiation for thе 1 1 l - 1 1 3 ; s o с i е t ya n d , 3 3 4 _ 3 3 5 Advanсеnrеntof SсiеnсеBеnсhmаrks' Аdаptаtioп апd Nаtиrаl Selесtitэп(G. С. 387,388 Williаms), 403-404' 619, 7 59, 7 62, Amеriсirn Сivil LiЬеrtiеs Union (AСLU)' 921 428,846 Adaptivе landsсapеmеtaphor, 560, 604, Аmeriсап Неbrеш,36О 860f Adaptivе plastiсity.Seс Phеnotypiс рlаs- Amеriсan Philosophiсal Soсiеty, З5, З6f Amеs, Oаkеs,416 tiсitv Arnino асids: homologous, 40f,. origin Adaptivе radiation, 793, 901_902 сlf lifе аnd, .54-59' 6О. Sеe аlso of ,439 Aеrоbiс огganisms'first еvidеr.rсе Protеins Afriса: dispеrsion from' 266_268, 694, AmplriЬiаns, 4|241^5 695-697; Lеаkеl' лd, 677_678

Afzaal,Ahmеd'з61, з62 Agаmсlspесi4 е1 s ,8 Agassiz'JеanLouis Rodolphе,404-406, 4 4 1 ,5 0 5 , 5 9 4 , 6 | 7 , 6 8 9 , 8 2 8 Аgе сlf Маlпtпаlsiп Еип-lpе,Аsiа апd North Аmеricс'ТДe(OsЬorn\,793 Aging.SeeSеnеsсеt-tсе

AnaеroЬiсbaсtеria,4З8_4з9 Anаgеnеsi9 s ,4 , 9 5 , 1 з 7 _ | з 9 ..Analogy,''owеn's usеof tеrm,212 A п t l p s i d s7,4 0 Andеrsоn,Еdgar,41'5-477,872' 892 Angiospегrrrs. Sсe Flowеringplants;Sееd plants 951

952

Iпdех Animаl Ьеhаvior, Lorеnz and' 692-69З Апimаl Dispеrsioп iп Rеlаtioп tсl Soсiаl B еhаuior (Wynnе.Еdrr.ards),

403

Апimаl Spесiеsапd Еuсllutit.lп(Mayr), 725,878 Апimаl Spеciеsапd Тheir Еuсllutirm (Сain)4 ' t74|8' 465 A n o l е l i z a r d s ", |9 6 - 1 9 7 Anstеy'R. L.' 95 Answеrsin Gеrrеsis(AIG)' з74-375 Antаgonistiсplеiotropyarguп1еnt, 922_92З Ar-rtiЬiotiсs' Ьaсtеriаlrеsistanсе to, 440 AntiеvоlutiоrrisIn, 370_З99;Lrаnning of е v o l u l i o n i s m3,7 О _ ЗZ- : f r t r u r ое f , 390_394; nеOсrеationism, З75-385; stаtесаsеstuсliеs, 386-390;thrееpillаrгsоf, 375-38.5'Sеeаlstl Сгеationisn-r; Sсiеntiiiссrеatiоnism Апtiquitуof Мап (Lyеll),7l 1 Antonoviсs,Janis,418-420, 8.52 A n t s ,3 0 7 - 3 1 0 ,6 5 6 , 8 75 , 9 2 З - 9 2 5 ,S е е сl/soInsесts Апts \!. S. Huхlеy),647 Апts,Thе (Е. O. Wilsсln),924 Apе-mant\eorv,257 .Гhought'' ..Apothеosis of Еvolutiоnary 1 H а е с k е Iьl .2 4 l Applе maggotfIу,192_|94'463 ..Apportionmеnt Human Divеrsitу' of Thе,' (Lеwontin),684 Aquinas,SaintThomas,757, 7.58 Arrtисаriаехсеlsа,З02, з0зf' з04 Arсhаеa.SeeAгсhаеЬaсtеriа AгсhaеЬaсtеriа, 132-13З, l.].]/,438, 538,539/ Arсhаеoptеrух, 42О-422, 421f ' 4 5З, 454, 518-521,520f Arсhaеprotists, 538 Arсhosaurs,740'741-742. Sееаlso Birds Аrdipithecus,258t' 260f,263' 269' 696 Aгgrrmеntfrom Dеsign,2, 25, 476, 61'8, 9 1 3 - 91 8 Argumеntto thе Ьеstехplаn:rtiсln' 758 A r i s t o t l е |, , 2 , З , 2 0 9 , 4 1 0 ,4 2 2 - 4 2 7' 5 5 0 '6 з 7 Arkilnsas,аntiеvсlllrtionism anrl,372, З73_з74.з84, 841' 842 Arkansаs СrеаtiсlnTrial, Thе, 428_429, 6t4 Arthropodpаttеrnthеоry,for сrusтaсеans'498499

Artifiсial l-ifе glrograms anсl еvolution, 429-4з3' 5.|з Аrt of Trаuеl, ТЙe (Galtсln),.597 Asirr.о,Frarlk, 41 1 A s t а u r о v 'B . L . ' 4 8 3 Astrоbiolоgy. .SсeЕхoЬiologv Аstroпсlmу апd Gепеrаl Phуsiсs Сllпsidеrеd tith Rеfеrепсе to NаtLrrаl Тbесllоgу (\Whеlvеll),974, 9 17 Aгmсlsphеrе,ргiпritivееarrlr.sаnd origin of lifе, 51-.54 Atomiс Wеapons tеsts.See Rаdiatiоn siсknеss Attaсhmеnt Thеorv. 642 Аt thе Zotl (.[.S. Huхlе1.),647 Augustinе, Sаint, 2 A u r o b i n d o ,S r i , 3 6 4 А u s t r a l i a ,o r i g i n o f l i f е a n d , 5 0 _ 5 1 АustrаlстpitЬесll-s,25 8/, 260f , 26з_26 5, 268_27 |' 677_67B, 69 з_697, 69 5f Austriа, soсiеtу'srесеption оf сvolution,

3з7

Autoсаtаlysis mсldеl,of \Иilsоn, [l6.5 t\l'tхin,as inhillitory influеnсе' .]0.5 Avian inflr-rеnzа virus (H.5N |I' 285,291r Ayаlа, Frаnсisсо J., З3f, 428,4Зз_436, 551,872

Batеson'Williаm, 219,7, Bаugh'Саrl, 375 Bеаglе(FlМS)' 8, 10l' 50 Bеak nrorphologу. sресi

re0f

B е е s ,5 9 l , 6 3 0 . 7 3 2 - - з 3 . Insесts Beеs of thе World, Tbе \\ 732-7Зз BеhaviorаIесology:сontr ogv, 5 42; еvolutiсlnаry and' 559_560; soсial Ь(

240-241

B е h a v i o r а lе v o I u t i l l nS' r r , tlrе study of Ьеlraviсlrа B е h ; r v i o гp а t t е r n s h . iolog 300, 307-310 B е h е .М i с h а е l . J 7 8 _ 3 - 9 , B е n t o п ' N , l .J . ' 8 l _ 8 2 . 8 9 . Bеrrz,Еrnst, 364 Bеrgmаnn's rulе, 4.5l, 83i Bегgs
D l D I l с J l с r е a t l ( ) n l s l n 'J J . Аlltiеvоlutionism; Crеat SсiеIrtifi с сIеationism

B а Ь с o с k ,Е . B . ' 4 8 4 ' 8 7 ] Bаby Faе,292 Bасtеriаl сvоlLttiоn,4З7_410; аdаptation and, 110; еrrdosуmЬiotiсorigin оf еukaryоtеsand, 534_541, 5З6/, 5З7f' 539f; mo]есular еvrlllrtionand, l з2_ lз.]' | 3Зf , Sее аlхl СyanoЬасtегia Baсtеriаl gеnеtiсs'678_680 Baеr, Kirrl Еirllstvon, 209_210,2"|1, 440-443,772.830 Bailеy, Dr. [-еl;rrard'29) t ] a i l l o t J, u I i е t '6 4 8 Bakеr, Неrbегt, 872 ..B:rlаnсе''thеtlrу оf сvоlution, 524, 602_60з Bаldwin, Jltrrrеs'.ii 1 tsаldwin Еffесt, .511 Balfour, F-rаnсisМaitland, 793 Bartholomеw, Gесlrgе,44з-444 Bаsis of PrоgrсssiL,еЕuolutiсllt' Тbе (Stеbbirrs),872 B а t е m а n ,^ . . | . , 2 4 0 l3atеs,Hеr.rryWаltеr, 444-416, 7 з6, 7з8,90з Batеsiаn mirniсrl', 444_445' a З(,-7З8

Biсhat, Хaviеr, 681 B l l l o m i а I n t l m е n с l . t r u r е ,b Bioсhеmiса] adaptаtiоn, е

108-1 1l Biоgеnеtiс law. See ..ontо latеs phyiogеny'' Biogеoсеnosis,838_8з9 Biogеtlgrа!hy' 447-152; c t h е < l r i е sЗ,- _ З 9 ; i n D з r r n а t t t г asIе l е с t i o nl,- , l l a n d . 8 l 6 : 5 i m p s o nl r r l с .VЙаllасе and' 90З-904; 9З0-9З1 Biologiсal |orns, 299_3 12 p a t t е r n s .J 0 0 ' з 0 7 _ 3 l 0 ; vaтiiltiсln,299-з00' з \с Irroгphсllogy, 29 9-З07 B i o l o g i с а |h o m o I о g v '6 J 8 B i o l o g i с а li n q u i г y .A г r s г o 42з-427 B i о l o g i с l I S с i е n с е sС L r г r i с

(Bsсs)'j71

BiologiсaI Spесiеs( ,llnсеp 180r, 181f,724,877 '.Biologу аs an Autotlomt ( A y a l а ) '4 3 4

lпdeх Ll Lifе programs and еvolution. 133,51.1 Г r а u е l ' . Г h е( G а l t o n ) ' 5 9 7 Frank, 4 1 I r v ,B . L . , 4 8 3 ology. Sсe ЕхoЬiologv lmу сшtl Gепеrаl Phуsiсs idеrеd ъuith Rеfеrепсе trl Nаturаl 9 14, 917 /оgy (.!7hеwеl|), lhеrе, pr:irrritivееагth's аnd сlrigin wеapons tеsts.Sсс Radiation еss nеnt Тhеor-y, 642 Zoo \J' S. Huхlе,v),647 inе, Saint, 2 ndo, Sri, 364 ia, origin of lifе аnсl' .50-51 ' tryi l b с'сtts' 258t' ]h0/' 26.]_]65. 271, 677-678, 69З_697, 695f , soсiеty'srесеption of еvolution, talysis rnсldеl,of Wilsсln, 86.5 as inhiL'itoryinfluеnсе,305 n f l u е n z аv i r u s ( Н 5 N l t , 2 8 5 , 2 9 1 Frаnсisсo .I.,З1f' 428.43з-4з6' 872 lk, Е. B., 484' 871 aе,292 al еvolution, 437-44О; adаptа. a n d , l l 0 l е n d o s 1 ' n l h i o г ioсr i g i n rkaryotеs and, 534-54|, 5З6f, -, 5З9f: пrоlесularеr,olution аnсl, - 1 3 3 ' 1 3 з l . S е еа I s с l -robaсtеria al gеnеtiсs, 678-680 iarl Егnst von, 209-210, 271, -443,772,830 Dr. Lеtlnаrd, 292 , Juliеt, 648 HеrЬегt, 872 rсе'' thеoгy сli еvоlrttion' 524, -60з in, Jamеs, 51 l in Еffесt, .511 r, Franсis Maitlaпd' 793 'lomеw, Gеorgе, 443-444 f Progrcssiue Еuolutioп' Thе э Ь i n s ) ,8 7 2 an, A. J., 240 Hеnry Wаltеr, 444_446' 7 з6,

, 903 444_445'7з6_7з8 ln mimiсrv,

B a t е s o nW , i l l i а m 'z 1 9 , 7 4 9 ,8 0 2 ,9 1 0 B а u g hC , a r l ,3 7 5 Bеаglе(IlМS), 8, l0f, .504-.506'593 Bеаkmorpholоgy,spесiationand, 189,

1e0f

B е е s , 5 9 1 ,6 3 О ' 7 3 2 - 7 з З . S е е с t l s o lnsесts Beеs of thе World, Thе (Miсhеr"rеr), 7зz*733 Bеhaviorаl есology: сontrastеd to еtholog,v' .542;еvolrrtionary ps,vсIrolсlgy and, 559-560; sосial Ьеhavitlr and, 240-24"1 Bеhаviorаl еvolutiоn. See Еthоlоgy and thе study оf Ьеhаviorаl еvоlutiс;n Bеhavior pattеrns' biologiсal forms and,

300'З07-310 B е h е ,М i с l r a е |З, 7 8 - З 7 9 , 3 8 0 'з 9 2 B е n t o nМ , ' J . ' 8 1 - 8 2 '8 9 , 9 6 , 9 9 Bеnz,Еrnst,364 Bеrgmann's rulе,451, 8З2 Bеrgson,Hеnri, 30, 446-447,56'1''645, 881 Bеrlin,Isaiah,584 Bеrmingham, Еldridgе,451 BiЬliсаlсrеаtionism'З73. Sееаlstl A l l t i е v r l l u t i о l l i s I lСl ;r е а r l o l l i s m ; Sсiеntifiссrеationism Biсhat' Хaviеr, 681 Binomiаl nomеnсlаturе,687, 87 6 Bioсlrеmiсаl adaptатion'ехаmplеs of, 108-l 11 ..Ontоgеny Biogеnеtiс law. See rесapitulatеs plrvlogеny'' Biogеoсеnosis'838-839 Biogеography,447_452; сontеmporary thеoriеs, 37_39;' in Darwin's thеory of nаturаl sеlесtiоn, |7, 18f, 19; Lvеll а n d , 8 l 6 ; S i r т p s o na n d , 8 5 9 - 8 6 0 ; .!7allaсе and, 90З-904; YаЬlokov and, 9з0_931 Biologiс:rlforms, 299_312; Ьеh:rr,ior pаttеrns' 300' .]07-310; сOlrtinuous vаriаtion, 299-з00, З10_З l l; sресiеs morphology, 299-З07 Biologiс:ll homology' 638 Biсllogiсаlinquirv, Aristоtlе on, 42З-427 Biologiсal SсiеnсеsСurriсulum Study

(Bsсs)'371

Biologiсal SpесiеsСr;nсеpt (Bsс)' l79, 180r,181f,724,877 ..Biology as an Autonomous Sсiеnсе'' (Ayala), 434

Biologу of Мorаl Sуstеms,Тhе (Alехаndеr),406 Biomеtriсs,9I0_9|z Biophilia,925 Biosystеmzrtiсs, 416 Bipеdalisпl, 263_264'269-271, 694' 696 Bird, !Иеndеil,384 Birds,452_455,518_.521; сlutсhsizе and lifе-historyеvolution,454, 567_568зLaсk сlutсh size,567_568i songsаnd spесiation'189, 190f;spесiаtion and,,194;'wеavеrЬirdsand soсialЬеhаvior,2З8_2З9. Seеаlso Flight Birds of Саmbridgеshire,Тhе (Laсk), 669 Birks,ThornаsR., 357 Blaсk hоlеs,429 Blaсkman,Сalvin' 751 Blainvillе'Неnri dе, 616 Blair,Fгank,194 Blind \YаtсЬmаkеr' Tbе (Dawkins), 513,800 Bluеgillsunfish,248 BlumеnЬaсlr, JohannFriеdriсh,82 1 Body plаns,Hox pаradoxand, ) - ) ) - ) ' ) \) ) \ { Bokеsoy'Isik,362 Bonnеt,СIrarlеs,209 Bootstrapping, 143 Borrеllo,М. Е., 620 Boulе, МarсеIltл,764 BowlЬy, lohn,642 Bowmаn,RсlЬеrt,595, 671' Bсrwman,T. Е', 491 Boх' Joan Fishеr,580 Brаdshаw,Anthony,4l8' 852 Brаdshаw,T еrrу, 123-124 Brain sizе,humanеvolutionstudyаnd, 256, 258-259t,260f,266, 268*269, 27t-272 BranсhG ' .' 385 Brеakagе-fusion-bridgе cус|e,752 Brеnnan'William, 37.5 Brеuil'Неnri, 76З-764 Brеwstеr,Dаvid, 7, 357' 894 Brеwstеr'Е. Т.' 359 Bridgеs,Саlvin,527, 528,747f' 750 BridgеwаtеrTrеatisеs:Palеy аnd' 3 6 2 _ 3 6 3W з h е w е l lа n d ,9 1 4 ,9 1 5 , 9 1 7 ,9 1 , 8 Broсa'sspеесharеа,564 Brongniагt,Alеxandrе,500

L).'3

954

Iпdех Bronn,GеorgеНеinriсh,442 Brooks'Williаm Kеith,74.5 Broom, Robеrt,265 Browеr,Linсоln P., 588 Brown,F. 8., 349 .!Иaltеr, Brown, 375 Brundin,Lars,632 Brunеt,Мiсhеl' 263 Bryan,WilliапrJеnnings,3.59,364, 84t5, 846-847 Buсklarrd,William, 502, .5l8, 698 Buсh u, Bеll, 546 Buеll,John, 376, з77 Buffon, Gеorgеs.l,ouisI,есlеrсdе,

4ss4s9,4s6f, 4s8f Bull,J.J.,Z9Z

BunЬury, С, F, J., 917 Burdaсh' Karl Friеdriсh, 440 B u r g е r ,R е i n h a r d , 7 0 1 Burgеss Shаlе, 459_463 Burghеs' Сhаrlottе Frankеn, 628 Burt, Austin, 890 Bush, Guy, 192-194, 463-464 Butlеrov' Alеksandr, 49, 54_55, 6.' Buttеrfliеs,736 Buttеr|lies(Ford),'587 By-produсt mutuаlism, 247 Сaесilians,414 Сain' Artlrur Jаmеs, З2, 417_418, 465466, 588, 725, 7 56, 956 Сaldеrwood, Hеnry, 3.57 Саidwеll, LLlгry, З88_З89 Саlifornia, аntiеvolutionismаnd' 388-з90 Сalvеrt, J
Саusеsof Еt',сllнtiсlп, TЙс (Haldanе)' 47t-472,629 Сavаlli-Sfогzа, Luigi Luсa,472-173 Сavalli-Sfоrzа_Еdwards gеnеtiсdis. tanсе,47.) Сеnanсеstor. SсeLаst сomm()nаnсеstor (LсA) Сеnоgеnеtiс fеаturеs, 210 С е n t r o m e r е 1s ,5 4 / '1 5 . 51' 5 8 ,1 6 7 Ссpаеаnеmоrаlissnаil, 465 Сеphаloсhordatеs, 582 Сhagasdisеasе, 43.5,506 С h a i no f b е i n g , 2 0 95' 5 0 Сhambеrs,RoЬеrt,6-7, 8f, 473-475, 6 4 9 ' 8 1 9 ' 8 9 3 - 8 9 6 ,9 0 З , 9 1 4 СhamЬеrs,Williаm' 47З-475 Chanсеand еvtr|ution ' 475-479 Сhаrlеswortlr' Bгiап,479-480'48()-48l Сhаrlеsrvоrth, Dеbсlrаh,479_480' 480-,181 Сhаrnov,Еriс, 568 Сhесk-listof Birds of thе World (J.Pеtеrs)'724_725 С h е е t h а mА' . H , , 9 6 _ 9 7 Сhеtvеrikсlv,SеrgеiSеrgееviсh, 481_483'.52З'.52t]'532, 88.5_886 Сhiаslllаtl'Рiе, 7 50 Сhiralitr', spесiationand, 20j Сhondriсhtlrуеs, 5 82-5 8 3 Сhristianit1':Amеriсаn еvangеliсаl, 4445; Dllrwin аnd,7_8, |9,25' еаrly сvolutiоnаry thought аnd, 2' 4' 6; natural sеlесtiоnаnd, 29_30; r-ratural thеolсlgvzlлd'757. Sее аIstl А r r t i е r ' o l t t г ii<s rl n ;R е li g i с l r r Christiаn nаtuгalism,354-3.'.5 Сh romсlsс.llпа l Еu сllutirlп iп 11igh еr P/azrs (StеЬЬins),872 Сhromosonrеs: in historу of lifе thеoriеs, 83; spесiationand, l 99-200. Sсс a / s r ,G е n o t l l ее v o Iu t i . . l г Сhronospeсiеsсollсерt' 94 Сh1'Ьа, С., 59 Сhytrid fungus, 414_4|5 Сiuil Biolсlgу (Huntеr), 846 ..Сivilisltiоn.. ( M ; l l ) ,. 5 4 s Сiuiltа Саttliiса, Lа,352, 353 Сladistiсs, | 42_14з, 2 |2, 26 |_262. 449-450,612,638,840 C l а d o g е n е s i s9' 4 , 1 з 7 - 1 з 9 ' \ 7 8 f С l а r k е ' B r y а n ,5 8 8 C l a r k е , С , v г i lA . , 5 8 8 , 8 5 6 - 8 5 7 Сlаssifiсаtion:Сuviеr аnd, 499-.500, 502; in Darwin's thеory of nаtttral

sеlесtion,17' 18f' 1\ and, 632-6З4; Lаm: 672_67З: Linnаеttsi 875_876: N{еndеlar a/so Phylogenеtiсs Сlausеn, Jеns, 483-48l Сlеmеnts, Frеdеriс,48 Сlеvеland, Lеmuеl R., Сlift, !(/illiаm, 79'5 Сlimatе сhаngе,41.5,I PlеistсlсеnеехtinсtiO Sее аlstl Сonsеrvatio Сlimbiпg Мtlltпt Imprt -)!-/

Сlinе, 646 Сlubnrossеs,690_691 Сlustеr analysis,пrolе studyand, 141-142 Сlutrоrr-Bгoсk,Т. Н., . Сoat сolсlr, of rаts, 46! Сoеlaсanth, 689 Сognitivе еthology, 54 Сohеsion SpесiеsСonс Сolе, B. J., 307-308 Сolе' Lamont,567,56 Colе'sparadoх,'568-5 Ссlloniаl lir,ing,in hist riеs,83 Сomеts. Seс Ехоbiolog Сomparativе gеnomiсs Сompatibilist nаturalis Сompеtitivе ехсlusion Сomplехity, еvolution

.tss-ss6, s-56/

Сoпrplеx spесifiеd intЪ 378, 379 Сomplех triits, аdaptа siеs, 1 15-1 16; florаl monkey floь.еrs'121 arсhеs,еаr ossiсlеs,а 716-121, 1 18-1 19l С сlmpы lgп аt hgи.s,.519 СonаIr Dоviе. Aгthur, ( Сonеry, Jоlrrl' 701 Сonfliсt, soсiаl Ьеhaviо Сonklin, Еdr,r.in,З6l Сonsапgttittuio', Iпbrе пetiс Drift (Сavalli-S Соnsсiousnеss'in histo riеs, 82 .Wilson Сonsеrr,ltion: а YaЬlokov and, 9З0-9 Сlimatе сl-rirngе Сoпsiliепсе (Е. o. Wils

Ittdех of Еuolиtioп, ТЙe (Нaldanе), 472,628 -Sforza, Luigi Luсa' 472-473 -Sforza_Еdwards gеnеtiс dis. , a7-, :еsтсlr.See Lаst сomr-non anсеstor

r)

: n е t i сf е а t u r е s , 2 1 0 m е r е s l' . 5 4 l '1 5 5 ' 1 5 8 ' 1 6 7 , пеmorаlissnail, 465 oсhоrdatеs,.582 435' .506 ; disеasе, o{ bеing'209, 550 r е r sR, o Ь е r t ,6 _ 7 , 8 f '1 7 3 4 7 5 , 8 I 9 , 8 9 3 - 8 e 6 .q 0 3 . c I4 lеrs,William,47З-475 47 5-479 : and еvоlutiсln, swortlr,Bu,an,479480, 480-48 1 sworth'DеЬоrah,479480, 481 lv, Еriс' 568 list of Birds of the \Yorld еtеrs),724_725 a m .t . H . , 9 6 - 9 7 rikov,SеrgеiSеrgееviсh, 4 8 3 , 5 2 з ' 5 2 8 ,5 3 2 , 8 8 5 - 8 8 6 иtуpie, 750 tv, spесiationand,203 riсhthyеs'582-583 anity:Amеriсanеvаngеliсal, l.5;Dаrwin arrd,7_8, l9, 2.5; , еvolutionary thoughtand,2, 4, rturalsеlесtionanсi,29_30;natuhеologуand' 757' Sее.llso Rеligion еvolutionisln; an naturalism,354-3-5-5 юsoпlаl Еuсl!нtiсlпiп Higbеr 872 rs (StеЬbins), losomеs:in lristoryof lifе thео. -l 83; spесiationand, 99-200.Sсс Gеnomееvolution ospесiеsсonсеpt'94 ' с.' 59 414415 d fr,rngus, iiology(Hunтеr)'846 s a t i o n "( M i l l ) , 5 4 5 Саttolicа' Lл' 352' З.5j riсs,142_14З,2|2, ) $|_262, 4 5 0 , 6 1 2 , 6 3 8 ,8 4 0 4 е n е s i9 s ,4 , | з 7 - 1 3 9 ' | 7 8 f , Bryan,588 , СyrilA.' 588'856-tl57 iсаrion:Сuviеrand,499-500' ; irrDarwin'sthеorуof naturаl

sеlесtiоn' 17' 18i' 1'9,21f; Hеnnig and, 6З2_631 ; I-lrпrаrсkаnd, 672-67 З1 Linnaеus and, 686_688, 875_876; Mеndеl aod,7З2_73З. Saе a/so Phylogеnеtiсs Сlausеn, .|еns,483_486, 532, 852, 872 Сlеmеnts, Frеdеriс, 484 Сlеvеland, Lеmuеl R.' 540 Сlift' \William, 79.5 Сlimatе сlrangе,415, 8] 6-817,8|7f; Plеistoсеnеехtinсtions and' 814_816. Sее аl sсlConsеrr,аtion СIimbiпg Мrluпt hпprrlbаblе (Dawkins), З27 Сlinе' 646 690_691 Сlr"rbmossеs, Сlustеr аnirlysis'mоlесular еvolution stltdy аnd, 141-1'42 Сlutton-Broсk, T. Il., 37,245 С o a t с o l o r , о f r a t s ,4 6 9 , 4 7 0 f Сoеlaсаnth' 689 Сognitivе еtholоgv. 543 Сohеsion SpесiеsСonсеpt, 179' 180t Сolе, B. J.' 307-308 Ссllе' Lаt-nont,567, 568, 569 Сolе's paradox' 568-569 Соlоnial living, in history оf lifе thеoт i е s '8 3 Сomеts. See Ехobitllogy Сomparativе gеnoпriсs,7 89-7 90 Сonrрatibilist nаturаlists' 32 l Сompеtitivе ехсlusion, 671 Сomplехitv, еvolutionary progrеssand,

-s-s5-.5s6, -5s6F

Сomplеx spесi6еdinformation (СSI), 378,379 Сomplех traits, аdарtation сontrovеrsiеs, l1.5-116; flсlral еvoluгion in monkеy flowеrs, 12|-124, 122f; gtllr arсhеs,еаr ossiсlеs'and jаrl.s, It6-121, I l8-1191 СсlmpsсlglшtЬgus,5 |9 Сonan Doylе, Arthur, 689_690 Сonеrу, John, 701 Ссlnfliсt, sс-lсiаlЬеlravior and, 2З9_240 Сonklin, Еdwin, 36l ()сlп sапp1tt i ll ttitl'' I п b r ееd iп g. а п d G епеtiс Drift (Сavаlli-Sfсlrza\,472 Сonsсiousnеss,in history сlf lifе theсlriеs, 82 Сonsеrvation:Wilsсln aлd, 92 5 -926: YaЬlokov аnd, 9З0-931 ' Sее аlsr.l Сiimatе сhаngе Сoпsiliеltсе(Е. o. Wilsоn), 925

Ссlnsiliеnсеof induсtions, 77 1, 91 6 Ссlпsiliеп се tlf I nd t,tсt irлls (whеwеl1)' 916 Сontinеntal drift, thеory of, 860, 904 Сorrtinuity hypothеsis,of languаgе еvоl u t i o n ,5 6 5 Сontrivеd dualism, 384' 395n1 Cоnvеrgепсе' 633 Ссlnvеrgепtаdaptаtion, 1 09 Сonway Morris, Sirnon' 84,462f Ссlok, Lаurеnсе M., '58[l Сoopег' Сlarenсе, 391,,з94 Сoре, Еdwаrd Drinkсr' 462f, 486-487, 487f,519,713,79з (iopе.s rr"rlе,66!, 832 Сoplеston, Еdward' 698 Сornе]l Univетsity, 3.'1' з52 ..С
9.'.'

956

Iпdех Сuri oиs Nаturаlists(TinЬеrgеn), 889 Сuviег,Gесlrgеs, 426, 441' 499-503, 644,68О_682;fina[сausеs,.5_6; GеoffroySaint.Hilairеand, 589, 606_607,637; |ryе|land, 698,699 a, 438, 775' 778, 778i' СyаnoЬaсtеri 77ef, 780f, 781f, 782 -l'З6-137: C.vtoсhтomе-с amino aсid , sеquеnсе ot, lЗ7-1 38, 138| еvolution of, 138fi nuсlеotidеdiffеrеnсes, l404 phylogеnyof сlrganismsaлd, 1'4lrf; ratе hеtеrogеnеity аnd, 144-747' 1.46f;ratеof molесularеvolution, 144-145,146f Dаеdаlus,оr Sсiепсеапd thе Futtlrе ( Н а l d a n е )6,2 8 D a n a ,J а m е s 3 , 58 I)апiеl u' Wаters,З72 DаphnеМajor, islеt,595, 596/ D а г Ь i s h i r еА,. D . ' 6 2 7 D а r l i n g t o nС, . D . ' 4 | 6 ' 7 2 2 [)arrow,Сlarеrrсе,845, 846 I)art,Raymond,694 Darwin, Сharlеs,7_14,9f' 24f' 504-508; Aristotlе and,4271 Baer and, 441;'Ьipеdаlity,269; СhamЬеrs ald, 4741сhilnсе,47547 6: 1.5;сrusСrеationistаttасkson, 514_.5 taсеans'494' Сuviеrand' 502; divеrsity of lifе, 80; еmЬryos,21I-2121 еvolutionaryprogrеss'550-551,.5.55; fossilrесоrd,99; Galipagos Arсhipеlаgo,593-594;Gаlton and, 5 4 5 ;G r a n t a n d , 6 | 6 _ 6 1 7G; r а v a n d , 6 1 7 ;H o o k е ra n d ,6 3 8 _ 6 3 9H ; rrxlеy ar-rd' 548;Jепkinand, 662_663;Iiving fossils,688, 689f,.Lyеll and' 5 0 5 _ 5 0 6 7, 9 9 ' 8 | 8 - 8 | 9 ;М a l t h u s zlnd,7ОЗ-704; mеdiсinе,5 14_51.5, 544;naturalhistсlгy,7.54;
D a r w i n , Е г a s m u s ,з , 4 , 7 , 5 0 4 , -508--t10,597, 644, 7 54 Darwin' Gеorgе, .504 Darwin, RсlЬеrt' 504, 508 Dаrшiп апd Dеsigп (Rusе),З48 Dаrшiп аnd His Сrlriсs (Hull), 839 Dаrшiп апd the Еmеrgeпсе of Еuсllutitlпаrу Theories of Мiпd аnd Bеhаuklr (Riсhards)' 5 1 1_512 Dаrшiltittltа (A. Gray), 6l8 Dаrшiпiаtt l7еritаgе' Thе (КoЬn), 517 Dаrшiпiап Lеft, A (Singеr), 864 Darwiniаn mеdiсinе. See Еvolrrtionary Ьiologу, of disеasе Dаrwinian opеratiпg svstеm,430 Darwirriаn populatiоns, .318 Dаrшiпistп аnd СаtЬoliс Thсшght (Dordolot), 354 Dаrшiпism апd l]umdn Affаirs (Alеxandеr),406 Dаrшiпisп Еt,rlluinТ (Dеpеw аnd WеЬеr), 327 Dаrtuiп сlп.Гriаl (Johnson),377,

383-384 Dаrtuiп's BlаckBсlх(Bеhе), з78,з79

Dаrшiп's D аngеroиsIdeа (Dеnnеtt|,44, 327 Dапuiп'sFiпсhеs(Laсk),595,67IJ,67l Darwin Studiеs,515-517 DauЬеnton,Louis-Jеan-М аriе,455, 457 Davеnport,Сhar|es,927 Daviеs,Nеal, 186 D a v i s ,G . Е . , 4 9 , ! ' Dаvis,Pеrсival,377 Dawkins,Riсhаrd,252.'з|5, з27, 512-51'3,874; rеligion aod, 44, 728, 7 5 8 ,8 0 0 D а w s o n 'С h a r l е s 8, 1 1 - 8 1 3 Dawson,John \Jfilliam,358, 360 D а y - a g еt h е o r vs. с i е n t i 6ссг е a t i ( ) n i s m a n d ,8 4 1 - 8 4 2 Daytorr'TN. SeeSсopеstriаl ..DеаdСladе Walking','662 Dе Bееr,Gavin,215 Dееp ArтhropodPhylogеnyproieсt,499 D еinonусbus,4534 54, 5.|9 Dеism.SeeRеligion D е l h r i i с kМ , з x , ь 7 9 ,8 8 6 Dеlgado,J.' 309 D е m Ь s k i\, W i l l i a m3,7 7 ,З 7 8 , 3 8 0 ,3 8 1 , 3 8 2 ,3 9 0 Dеnnеtt,Darniеl, 44, з2I, З2z' 327' 874 DеoхyгiЬoпuсlеiс aсid.SeсDNA Dс pаrtibusаtzimаlium(Aristоtlе),2

Dеpеw'Daуtd,327 Dеsсаrrtеs, Renё,7.5 Dеscепtof Мап, ,tп Rеlаtioп to Sех'7 2 1 _ 2 З ,5 0 7 , 5 | 3 4 0 8 ,4 1 0 ;. . е v o l u tionarуpsyсholo t i o n ,6 1 8 ;r а с е ,8 2 Dеsignlпfеrспсс,Т| Dеsigп of Ехpеriпе Fishеr),580 Dе Sola'Abrahaпr,: Dеvеlopmеntal Ьiol аrnddеvеlopmеn Dеvеlopmеntal rrеt Dеvеloрmеntа l.sуst ..Dеvеlopmеnt Нypс (Spеnсеr,), 867 Dеuеlopmепtof Dаt (Ospovat),515 DеVorе,Irvеn,642, Dialесtiсalmаtеriа Diapausе'805 Diapsids,740 Diaz, Anita, 184 Diffеrеntiа1 аЬundа ra] sеlесtion, 306Diffегеntiatеd сеlIs,i oriеs,83 Digitalеvolution,42 D i n o s a u r s2, 6 , 2 6 f ;I aлd,45З454,74 сausеsfor ехtinсt 716-718 Dinosaurs:Тhе mod rton, 51.7-522 Dioесy,848 Dirесtеdpanspеrmi Dirесtionаlsеlесtio DisсovеryInsritutеj 192 191 tC4

Disеasе:in1Ъсtious, а duсtion, 57 1_572; 285, 291,595-59( Еvоlutionary biоlо parasitе еvсllutiotDispеrsal biogеogrа D i s s o с i a b i l i t l '2, | 8 , 2 Distаnсе mеthсlds,of struсtion, 139_|42 Divеrsifiсation, 84-9 сomparеd, 87_89, Ьcrс

Я4_Я\.nltto'

Plrilosоphyof еvol

Iпdех w i n ,Е r a s m u s3, , 4 , 7 , 5 0 4 , )8-510, 597, 644, 754 win, Gеorgе,504 tvin,Robеrt,504, 508 t,t,,iп аnd Dеsign (Rusе),348 шiп апd His Сritiсs(Нull),839 шiп апd thе Еmеrgепсeo|. uсllutirпиrу Thеories of Мiпd апd ehаuior(Riсhards), 5 |1_572 ш i п i а п а( A . G r а y ) , 6 1 8 luiпiапHeritаgе,Thе (Kohn),517 шiniаn Lе|i, А (Singег),864 winiаnmеdiсinе.SeeЕvolutionaгy iology,of disеasе winian opеratingsystеm'430 winianpopulаtions, 3 18 .t,uiпism аnd Саthсlliс Tbtlugbt )оrdolot),354 ,tuiпismапd Humап А[t'аirs \lехandеr), 406

.tuitlisпl Еt,сlluitlg (Dеpеw

and

VeЬer),327 ,шin oп Тriаl (Johnson|,377, 83-384 ,tlliп'sBlасk Bс'я (Bеlrе),з78' 379 .luiп'sDаngerousldеа (Dеnnеtt),44, 27 ,t,t-,iп's Fiпсbes(Laсk),595,670, 677

.wln

)tudlеs' ) l)-J

l /

:bеnton'Lou,is-Jеаn.М arie,4 55' 4 57 /еnport'СЬar|еs,927 liеs,Nеal, 186 l i s ,G . Е . ' 4 9 1 lis, Perсlval,З77 мkins,Riсhаrd,252,31'5,327, 12-573' 874;rеligionand,44,728, 58,800 м s o n ,С h a r l е s8' 1 1 - 8 1 3 vson'Jоhn !Иillianr,358, 360 /-agеthеory'sсiеnтifiс сrеarionism nd,841-842 lton, TN. SeeSсopеstrial :аd Сladе !falking''' 652 Bеeг,Gavin,215 :p Arthropod Phylogеnyproiесt,499 пoпусhus,45з454, 519 sm. SeeRеligion briiсk, Мaх, 679' 886 gаdo,J., 309 n b s k i ,W i l l i a m ,з 7 7 , 3 7 8 '3 8 0 ,з 8 1 , 82' З90 l n е t tD ' a n i е l ,4 4 ,З 2 1 ,З, 2 2 , 3 2 7 , 8 7 4 lхyribonuсlеiсaсid. Seс DNА pаrtibнsапimаlium(Aristotlе),2

Dеpеw,David, З27 Dеsсartеs,Rеnё, 759 Desсепtr.lfМап, апd Sеlесtklпitt Rсlаtioпto Sех'Thе (С,,Dаrwin)' 21-23, 507, 513-515,.544;altruism, 408' 410; ..еvolution,' аnd,29; еvolutionarypsyсhology,557;grоupsеlесrion,618; tacе,821-822,862 DеsigпIпfеrепсе, TЙe (DеmЬski)'381 Dеsign of Ехpеrimеп,s,ТЙe (R. A. F i s h е r )5, 8 0 Dе Sola,AЬгahаm,360 Dеvеlopmеntal Ьiology'SgсЕvolr.rtiоrl and dеvеlopmеnt Dеvеloрmеntalnеtworks' 898-899 Dеvеlopmеntаl.systеn-rs thеоry, 320_з21 ..Dеvеlopmеnt Нypоthеsis,Thе'' (Spеnсеr.), 867 Deuelopmепtof Dаrшiп's Thеorу, Thе (Ospovat),5f5-517 DеVorе,Irven,642,889 Dialесtiсalmatеrialism, 685 Diapausе,805 Diapsids,740 Diaz, Anita, 184 DiffеrеntialаЬundаnсе, fоrmsand nаtural sе|есtion,306-310 DiftЪrеrrtiatеd сеlls,in history of lifе thеoriеs,83 Digital еr,olutiotl,42943З Dinosartrs, 26, 26f: Ьird еvolution and,4534 54, 742|,еxtraterrеstriаl с.rusеsior ехtinсtiOnоt. 4 l l -4 l 2' 7 1 6 - 71 8 Dinr>saurs: Thе modеlsystеmfor еvolu. tron, 517*522 Dioесy,848 Dirесtеdpаnspеrmiа,787-788 Dirесtionаlsеlесtiorr, 9l 1 Disсovегylгrstitutе, 38.5,3[.l8,389, 390, 392.,з9з, з94 Disеasе:infесtious, and sеxualrерrod u с t l o I . l '5

l-5 / l: lnfluеnzn virusеs,

285' 291,58.'-586.Sее аlsсl ЕvolutionaryЬiologу,of disеase; Host parasitееvolutiorr DispеrsаlЬiogеographеrs, 450 DissoсiaЬility,218, 220 Distanсеmеthods'of molесularrесon. stfuсtion' 739_742,140t, 14]rf Divеrsifiсation , 84-9З; larrdand sеa сomparеd,87_89, 88l' 90_91f,. nunlbers,84-85;рattеfns.89_9.]'90-91f; philosophyof еvolutionary thought,

З13-З14; thеorеtiсalmodеls,8.'-86, 86f Diuеrsitуof Lifе (Е. o. Wilson), 925 DNA: сonfigurаtionof' 134f' 906-9О7, 907t сrustaсеans'497 -498, 499 evolutionof, 67-68; hydrothеrmal vеnts thеoryand,58' 68-69;Kiпruraand, 6 6 6 - 6 6 8 lM i I I е r . U r ее1х p е r i t n е n г аnd, 56; Nеi's gеnеtiсdistanсеand' 766;prесurso rs of, 6З-67. Sеeаlso Gеnomееvolution;Мolесularеvolution Dobzhanskу,Tl-rеodosius, З2' Зз, З3f' з4f' 179, ЗI4' 522_526,532, 561, 60з_606,882;Ayаla and,4344351 Сhеtvеrikovand,48З; Сlausеnаnd, 485;есologiсаlspесiation,187, 194; Lеwontinand' 682, 684;Mayr and, 725, 878; Mсlrgan and, 528, 529; random drtit,476477 ; rе|lgion,522, 525; Sеpkoskiand, 856;Shеppаrd a n d ,7 5 6 . , S i m p s oаnn d ,8 6 1 ,8 8 4 ; s t е b b i n sa n d , 8 7 2 , 8 9 2 DoЬzhansky-Мullеr modеl'184-l 85, 1 8 s f ,2 2 6 Dohrn' Аnton,62) D o l I i n g е rI.g n e z4' 4 0 DominiсanSamplingIntеrval,98/ D'OrЬigny,Alсidе,502 Dordоlot,Неnri dе, 354,362 Dоuаdy,s., 301_30.5 DouЬlеfеrtilization, in sееdplants, 848-849,852 DouЬlе lrеliх,1З4l, 906,907f DсlubleHеliх, Thе (J. Wаtson),907 Dovе,!Иilliam'490 Dovсr,PA, аntiеvolutionism and,391, з92-з93 Dгаpеr,John, З50, 351 D r i е s с hН , а n s ,3 0 ' 4 4 6 ' 6 2 2 , 6 2 5 , 7 4 6 Drosсlphilа,з4f' 36f,37f, з9,4of' 155t' 526-530, 527f; Сarson and,467, 468; Саstlе and,469i Сhеtvегikov аnd,482; Сrow аnd,488_490; DoЬzhanskyand, 523;gеnomеs' 1 5 8 - l 6 0 ' 1 6 0 f ' 1 6 7 - | 7 0 ;h o m е o t i с mutations,2|9 ' 220i; N{aynardSпrith and, 7 211Моrgаn and, 659, 746, 747f' 749_750;Mullеr and,751_752; RoЬеrtsonand, 833-834;Sеpkoski a r r d ,8 5 6 ;s p е с i a t i o n1'8 4 - 1 8 5 ,1 8 7 Dгummоrrd'Неrrry,З57, 364 D r u r v , ' W i l l i a m8, 8 9 D u b i n i n ,N . P . , 4 8 3 , 8 l J 5

958

Indeх Duсk.Ьillеdplatypus,688, 689f Dumёril,Andrё-Маriе-Сotlstant, 6 8 0 - 6 8I Dr-rnrr, Lеsliе' 524 Duprё,John, 326 Durklrеirn,Еmilе, 864 Duvеrnоy,GеorgеsLouis, 681 Dwight,Thomas,3-54

ЕmЬryos: сolttеlnporarv thеоriеs, 36f. аs еvidеnсеof еvolution, phvlоgеllv, аnd l-romology,210_2 | 3; simi1aгitvof humаn аrrd d
Еmlеn's. T.,2.+1 Еndlеr,Jоhn,11l

ЕndosymЬiotiс origin of еukаryotеs, 5з4-547' 5з6f' 5з7f' 5з9f' 712_71З Еzrrossiсlеs'adaptzrtiоIr аrrd,l18_119l, Епtе lесhу. Sсс Vitаlisrn 2|З F,пttuiсkеlu ttgsgеsсh i сb t е dеr Т |li еrе, D iе Е a s t ,Е d w a r dM u r r а y ,4 | 6 , 9 2 7 ( B a е r ) ,4 4 - l Е Ь e r t ,D . , 2 9 2 Епz,уmеs(Наldanе), 628 Есologiсaldеvеlopmеntal еvolutiоnarу Е с э h i p p u s , 7 1 4' f7 | 5 Ьiologv,227-228 F-,рigеnеtiсь. 8qB_Бq9 Есologiсаlgегlеtiсs. 531-532' .'86_588 Еplirrg, С'arl' 872 Есologiсаl Gеnеtiсs(Ford), 531-532, Ёpoquеs dе l.l паturе (Buffon),457_458 5 8 6 ,5 9 7 ,9 3 0 Еppеrsсlпu. Аrkапsаs, З72 Есologiсаl Isolаtiсlпiп Birds (L'aсk)'671 Е q u i d s ,a d a p t a t i o na n d , 1 1 1 - 1 1 . ] ЕсolоgiсаlSpесiеsСonсеpt,179, 180t, Еquilibrir.rmmсldеlsof divегsifiсation' 181f 89-92,93 Есologiсalthеory'biogеilgгаpЬiсal, 4.5l Еr.lviгr'D. H.' 9.5 Есology.SeeBеhaviorаlессllсlgy Еsсhatolog1',.]64-З65 Есoplrеnotypiссhangе,95 Еsсhеriсhiа аlli,4З9 ЕdiпburghRеuieш,698 Еssа1'сlп Сlаssifiсаtioп (Agassiz), Еdtuаrdsu. Aguillаrd, З74, з7 5_з76, 404-405 384 Еssау ott thе Priпсiplе of Populаtirltt' Еffесtivеpopulationsizе,gеtlomееvoluА z ( M а l t h u s ) '] 0 ' 1 з l ' 1 4 ' 7 0 з ' 9 | ) 4 tiorrаnd, 153 Еthology аrrd tlrе sгudy сlf Ьеhаviorаl ..Еffесtsof Variаtion on Fitnеss'Thе,' еvоlution, .5,l1_543, 637, 888-8 89 ( H a l d a n е )6,2 8 ЕuЬaсtеria4 , 3ti,538, 539/ Еgypt,Napolеon'sехpеditiontсl,500, Е u с h r o m a t i n ,1 5 9 , 1 6 0 , 1 6 2 s01f,606 Еr"rgеniсs, 544-5471'disеilsеand, 293; ЕhrеnЬеrg,СhristianGottfriеd'437 G а l t o n а n d , ' 5 9 7 .. 5 9 8 _ 5 9 9 8 , 62; Еigеn,Мanfгеd'532-.5.33 Pеarson lrrс1,800, 801; RоIrr:rrr Ёlап uitаl.SeeVitalisrrr Сatholiсisrrr' З54; sосiеty аrrс1,З41 Еlаsmosаurusplаtуurиs,462.f, 487f Еukаryоtеs:Ьасtегiааs, 439; dеrivation Еldrеdgе,Nilеs: Сharlеsworthand' 480; оf word, 535l in histсlrytlf lifе thеoеХtrаPolism'3 17;miсгtlеvolution аnd r i е s , 8 1 , 8 3 ; M a r g u l i s a n d , 7 . l2 _ 7 1 З ; maсroеvolution, 126_129; punсtuatеd rnolесulаr еvoltrtitlnand, 1 32- l З.1, еquiliЬгium,37, з7i' 94_95, 61|_61'2: [3Зft PrесrurlЬriаnpеriоd, 782_784. Rar"rраnd, 824-8251'Simpsonand' Sее аlso ЕrrdosymЬiоtiс origin оf 86l; soсiеtyand, 334_335 еukaryotеs Еlесtrophorеsis, gеnеtiсsаnd, 602-60З Еvangеliсal Сhristianity. Sсс Еlеmeпtsof ЕхpеrimеntаlЕmbrуolog1,, A n t i е v r э l u t i r l l r r sС mhl г i s г i l ni r y Тhe (l. S. Нuxlеу),646 Еvе, R., З73 Еlеnlеlttsof Gеologу(Lyеll),816 Еuеr siпсс Dаrшiп (S. J. Gоtrld)' 6i4 ..Еvidеnсе Еlерhаnt'snosе'43l аgainst еvоlutiоn,'.З84_.]85, Еliot, Gеorgе,867 3 8 8 - 3 9 1 'З 9 4 Еllwangеr,Pаul' 373 Еuidепсe аs tсl Мап's Plасе iп Nаturе Еmbrас:bеmепts, 6З7 (T. H. Huxlеv), 6.50 ЕmЬryologv:сontеmpori]гy thеoriеs'39; Еuidепсеstlf Сllristiаtlity (Palеy),3.50. irr Dаrwin's thес.lг1,'
Еvo-dеvo. See ЕvrэItrtion tal Ьiology ..Еvolution'' ; popularizеd 2 8 _ 2 9 1 u s е dЬ у D l r r r i l . Еutllutiоп 1DoЬzh.rnьky.. StеЬЬins' and Vаlеntinе Е u o l и t i о п { j о u r n a I )З, 5 , . Ешllutioп: ТЙe Fl,s-si/sSa 428 Еt,rllutioп: Thе Мrldеrп S H u х l е y ) .З 2 , \ з 4 ' 4 4 - . 646,647 Еuolutitlп апd Adlp!а!it'l Мorgan), 746' 748 Еuсllutioп апd Сhristiаn l З64 ЕvоIution and dеvеlсlpm body plans and Hoх pа 222_225.223[ Jеvеlot s г r а i n ta n d d i s s o с i a Ь i l есologiсаl dеvе|оprrlе 22a_228: еmhryos as с 21 0_21 3 ; еvo l r"rti onary o p m е n t а I$ е n е t i r s 2. I 9 r o с h r o n y .2 l З _ 2 l . 5 ;m а а n d m i с r о е v o l u г i o n2' 2 ral pаrаllеls, 208-210 ,.Еvolution аnd Еthiсs'' (. 651 Еuсllutioп апd lu,l,tism (K

360

Еuolutiоп апd thс Gспсti, Populа t ioпs t S. Vгight 1 Еtч'lнtioп апd ТhсоIt',gl'I з64 Еuolutioп апd thе Theorу (Мaynard Smith)' 723 Е v o I u t i o n а r i I sy t а Ь l еs t r а -22--lJ. 240. 600. 85 Еvolutionary Ьiologу, of d (Г)arwiniirrrrnесliсinе),2 аdaptation, 284-28 5 , 2i nсlsisdесisiontrсе,287293_294: mutationgеn svmptoms and с;lusаtitl Еvolrrtionary Ьiolog,v,pЬiJ З 1З-З29: ЬiоIояy'sсоrr philosophy, 321-327; p сontriЬutit-lпto Ьiology Е v о l u т i o n а г yс o m р u t i n ga algоrithms, 549-.550 F , v orIr г i o n a r yd е v е | o р l l l е ( е v o - d е v о )3' 9 ' . +I _ . l ] ' . 638, 830, 8-18,909-90

Iпdeх os: сOntеmporarythеoriеs' 36f; as еnсе of еvolution, phylogеny, аnd rology,210-213; similarity of rаn anсl dog, 21_23 |os ап(l Апсеstors (dе Bееr)' 21.5 ' S. Т.' 24| ,John,111 yrnbiotiсorigin of еukаryоtеs, -547' 5з6f, 537f' 5з9f,712_713 сhу. Seе Vitаlisnr -Гh :keluпgsgеsсh iсh tе d еr iеrе, D i с 'r1,441 les (HaIсlanе),628 эus,714f'775 .еtiсs'898-899 , Сarl' 872 еs de lа паtиrе (Bоffon|, 457458 ;r.lпu. Аrkапsаs, З72 ; , a d a p t a t i o na n d , 1 1 1 _ 11 З l r i L r n tm о d е l so i d i r ' е г s i f i с a t i о n , )) 9t D. H., g5 ology, 364-365 'iсhiа сrlli,439 oп Сlаss ifi саtioz (Agаssiz), -405 oп thе Priпсiplе сlf Populаtioп, М a l t h u s ) '1 0 ' 1 3 / ' 1 4 , 7 0 з ' 9 o 4 gv аnd thе studv сlf Ьеhаvior.аl u t i о n ,5 4 1 - 5 4 3 , 6 з 7 , 8 8 8 - 8 8 9 : е r i a ,4 3 8 , 5 3 8 ' 5 з 9 l ) m a t i n ,1 5 9 ' 1 6 0 , | ь 2 сs, 544-547; disеasеаnd, 293; o n а n с l ,5 9 7 , 5 9 8 _ 5 9 9 ' 8 6 2 ; s o n a n d , 8 0 0 , 8 0 1 ;R o m a n roliсislт, 354; soсiеtv and, 341 .oгеs:Ьасrеrie.ls. 439; dеrivatiсln .ord, 53.5;in history of Iifе thеo8 1 ' 8 3 ; N 4 а r g u l i .asn d , 7 1 2 _ 7 1 З ; :сular еvоlutiоn anсl, 132-133, .; PrесаmЬrian pеriod, 782_784. z/soЕndosymЬiotiс origin of tryotеs lliсаl Сhristiаnit1'.Sсс еvolutionism;Сhristiаnity

.,37З псеDаrшiп(S.J. Gоuld),614

nсе agаinst еvolutiol-t'''384_385' -з91, э94

се аs to Мап's Plасе iп Nаturе {. Нuхlеy)' 650 сеs of Сbristiа|1itу (Pa|еУ), з50, lrttrnIthе
-57_75Il

Еvo.dеvo. Seс ЕvсlIutionarydеvеlopmеntal Ьiology . . Е v r t | L l r i o np. 'o: p u l а r i z е d Ьy Spеnсеr. 28-29; usеd Ьу I)arrvin,29 Е L,'о l utiсlп (DoЬzhansky, Ayal:r, StеbЬins,and Vаlеntinе),872 Еuolutklп ( journаl)' з5, з6f, 725 Еuolutioп: Тhe FrlssilsSay Nol (Gish), 428 Еuсllutklп: Tbе Мodеrп Syllriсsis (J. S. Нuxlеy),32, зз4, 447, 547-549, 645, 646,647 Еuolution апd Аdаptаtioп (T'H' Мorgаn), 746,7+8 Еuolutklп апd Сhristiап Htlpе \Benz|, 364 Еvolution and dеvеlopment,2О8-236; Ьody plans and Hoх paradoх, 222_225, 223f; deve|opmеntсonstraint and dissoсiability'2| 5-219; есologiсal dеvеlopmеnt and' 227_228; еmЬryos as еvidеnсе in, 21 0_21З; еvolutiсlnаryvеrsus dеvеlopmеntаl gеnеtiсs'2 |9.221 1 hererсlсhrony, 2 | З_2 | 5 ; mасrсlеr,оlutiоn and miсroеvo|uttoп, 225-227; tеmpo. rаl parallеls, 208-210 ..Еvolirtion and Еtlriсs'' (T. H. Нuхlеy),

6,s1

Еt'сllutioпаnd J udаism (Krauskopf),

360 Еuolutioпапd thе Gепеtiсsof .Wright)' (S. Pr>pиIаtioпs 929 Еuolutioп аnd Tbсologl,(Меssеl-lgег), з64 Еurllutiсlпапd thе Тheorу of Gаmеs (МаynardSmith)'723 Еvolr.rtionarily stаЬlеstratеgy(ЕSS), 2 4 0 , 6 0 0 , 7 2 2 _ 7 2 З8, 5 з ЕvolutionaryЬiоklgy'of disеаsе (Darwiniаnmес1iсinе), 281_298, 9231 adaptation,28 4-285, 289-29 2; diagnosisdесisiontrее.287-288;flrtr"rrе of, 293294; mutaтiongеnеtiсs' 28.5_289; symptomsаnс1саusаtiоn,2-8|-284 ЕvolutionaryЬiology,philosophyаnd, З7 3-329; biology'sссlntriЬutionto philosophy,З21-З27; philоsophy's сontriЬutionto Ьiology,з14-З21 Еvolutionaryсoпlputingar.rdgеIrеtiс algorithms,549-550 ЕvolutionarydеvеlopmеntalЬiology (еvo-dеvo), з9, 4-l'-42,310-3 11, 3з5' 6 З 8 ' 8 з 0 ' 8 3 8 '9 0 8 _ 9 0 9

Еtlсllutirlпаrу G епеtiсs (Мaynaгd Smith), 723 Еvolutionary progrеss' 550-557' 894; Gotrld and, 672; Мoпаd trl Маrl, 744_775; sресifiс trеnds аnd diffiсultiеs, 554-556, 556f, trеnd thеory, 552_554, 553fi valuе еvaluation diffi. сultiеs, 551-552. See a/so Soсiаl Dirrwinism Еvсllutionary psyсhоlоgy, 37' 557_560 Еvсllutionary qЦantitativе gеnеtiсs' 701 Еvtilutionary SpесiеsСonсеpt, 179,

r 80,

Еurllut ioпаrу Th сorу апd Сhristiаn Bеliеf (Laсk),67| Еvolutionary thought, historу оf, 1-48; сontеmporаIy, 35_45; bеfоrе I)arwin, 1_7; Darwin and,7-14; Tbе Dеsсent of Маn аnd, 21-23; еvolu. tion as popul:rr, not profеssiona[,sсi. еnсе' 23-30; Оп tbе origiп of Spесiеs aлd, |4_22: synrhеtiс thеory.

30-35

Еurlltttiсlп сrёаtriсе, L' (Bеrgson), 446, 812,881 Еuolиtioп Dесeit, The (Yahуa|, 361 Еuolиtioп iп Age-Strиctured Populаtioпs (B. Сharlеswo||h),479 ..Bvolution in Меndеlian Populations'' (S. Wright), 560-562, 928 Еvсllution of languаgе, 562-566 Еvolution of lifе historiеs, 567-57О. Sее a/-soorigin of lifе Еvolr:tiоn of seх, 57О-572 Еuсllutioп of Sех, Thе (Мaуnard Smith), 722 Еwеns, Warrеn J', 572-574 Еwеns Sаmpling DistriЬution, 57З Ехrrеr, Sigmund' .591 Ехobiоlogy, 574-577; еxtinсtion and' 4||412,716-7t8; originof lifе and, 52-54, 59_6О,7 з 5' 7 87-7 88 Ехpansion modеls of divеrsifiсаtion'

9z-9з

Ехpеriments апd Оbseruаtiсlпs of Hуbridizаtioп iп the Plапt Kiпgdom (von Girtnеr), 7З0 Ехplапаtioпs (R. СhamЬеrs), 474 Ехponеntiаl modеi of divеrsit1',8.', 86/ Ехpressiсlп tli tЬе Еmotiotts iп Мап апd fu Апimаls, The (С. Darwin), 507,

s57

Ехtепded P h епоtvpe, ТЙe (Dawkins), З|6-з17' 327

9.SL)

960

Indех Еxtinсtion:Сuviеr and, 499-502' 5О1f; еаrliеstеpisodе,784;еxtratеrrеstrial сausеsfor, 411412-,716_7181 JaЬlonskiand,662.Seeaiso Мass е x t i n с t i o n sP;l е i s t o с е nееx li n с т i o n \ Еxtrapolаtionism, З 17_З18 Ехtratеrrеstriallifе. SeeЕхoЬiology Еyе-сolorinhеritanсе,749 Fеathеrs,45з,520-52| Fеlsеnstеin, Josеph,578-579 Fеrnald'М. L., 871 Fеrri,Еnriсo,864 FеyеraЬеnd, Paul, 325 ЕiЬrinopеptidеs'ratе of molесularеvolution, L46, 146f Fidlеr,НеlеnaAlехandrovna,887, 88B Final сausеs:Darwin'sthеоryof naturаl sеlесtion'2З-25; еarlyеvolutionary thoлght,2_7 F i s h е rR , o n а l dA y l m е r ,3 1, З 1 4 , 4 1 6 , 465, 560, 579-581;Саvalli-Sforza and,,4721сhаnсе,477; Сhеtvеrikov a n d ,4 8 3 ; F o r d a n d ,5 8 7 , 5 8 8 ;g е n е t i с s6, 0 1 _ 6 0 2 H ; a l d a n еa n d , 4 7 | , 627-628;mutаtion'218; Pеarson a n d ,8 0 1 ,8 0 2 ;S е p k о s kai n d ,8 5 6 ; sехualsеlесtion,|97_198'.!Иright and, 927, 928 Fishеr,Ruth, 580 Fishеrianrunawayproсеss'197_198 F i s h е s 1, 9 1 _ 19 2 , 1 95 , 2 4 8 , 5 8 1 - 5 8 4 , 591 .!Иaltеr Fitсh, М., 584-586 Fitсh-Мargoliash mеthоd,5 84_585 Fitton,!(illiam, 698 Fitzroy, RoЬеrt' I\f' 504 Fixеd aсtion pattеrns'541_542 Flеishman,Leo, 196 Flеming,AmЬrosе,З59 Flеming,Donald' 350 Flight: еvolutionof, 453-454; in history of lifе thеoriеs,82 Flood gеоlogy,3 59,з7з, 841-842,84Зf Flrlrа lпdiса (Hookеr),639 Florа of Nсlrth Аmеriса (Grаy and Torrеу),6\7 Florа Tаsmаniае(Нookеr|,6З9 Flowеringplаnts:еvolutionin monkеy flowеrs'121_124,122f insесtsand' 658-659;Linnaеus'sсlassifiсation of, 687. Sеea/soSееdplants FlotuеriпgPlапts:ЕuolиtitlпаbсluеtЬе SpесiеsLeuel (StеЬЬins), 872

FIuсtuatingasymmеtry' 9 З0_9з1 }-ogеl,Lawrепсе, 549 Fоl, Hеrmann, 622 Footе, М., 100 Fоraminifеrа, 691 FоrЬеs,Jamеs David, 91 7 ,.ForЬiddеnmorphologiеs,'' 21 6 Forсе, Allаn' 701 Ford, Еdmund Brisсo, з2, З4f, з14' 4 6 5 . 5 З l _ 5 з 2 ' 5 8 6 - . s 8 8 '6 6 0 , 6 6 , 5 , 856, 9з0 F-ordyсе,J., з49 Form and funсtiоn, 299,609, Sее аlзo Biologiсal forms Form апd Fuпсtion (Russеll),.588-590 Fоssiis/fossilrесord: аdaptation, 106; Agassiz's fish' 405f, Ьасtеria,438; Burgеss Shalе,459_463; Соpе and, 486-4871in С. Darwin's thеory' 18_19,18f.Е. Darwin and, 509; divеrsity thеoriеs,85; еarliеstpossiblе, 70; еarly еvolutionary thought' З; еvolution of languаgе,.564;gill аrсhеs, еаr ossiсlеs'and jаws аdаptation, 1'|6_|21, 1 18-1 19f; human сvolution study' 256_25 8, 26 1-26з, 268-27 0 ; insесts,657_6 58, 659; JaЬlсlnski and, 661._662;marinе, 87, .582;Мarsh and, 713, 7 14f' 71 51 miсroеvolution аnd maсrсlеvolution,126-129; pаlеoЬiology and quаlitv of, 98_101; Prесambrian pеriod, 77 5*7 84' 777f' 778f' 779f' 780f' 781f' 785f spесiation, 203; taphonсlmy,879-881. See a/so Living fossils; Luсv F o u с a u l t ,M i с h е l , 4 9 9 Foundation for Thought and Еthiсs (FТЕ|, З77 F o u n d е r - е f f е сm t o d е |o f s p е с i a t i o n .

r99f,202-203,477

Foundеr-Flush Тhеoryrlf Sресiiltion, 467 Franks,Nigеl, 307' 308 FrееdomЕuoluеs(Dеnnеtt), З27 F.rеud, Sigmund,624f Frisсh,Karl Rittеrvon, 541,591-592, 6 9 3 ,8 8 8 ,8 8 9 Frogs,413-414 Fruit fliеs' SеeDrosсlphiLt Fry, Iris,577 Fиll Housе: Thе Sprеаdof ЕхсеIlепсе frсlm Plаtrl tсl Dаrшiп (S' .l. Gould), 612 Рuпdаmепtаls,Thе (pampЬlets), З.58

Fi.ir Dаrtuiп (|.. Мiillеr), Futurе of Lifе, Thе (Е. С

GаЬriеl' Wilfriсd, 701 Gaia hypothеsis'576, 71 Gal6n, Fеrnаndо, 434 Gal6pagos Arсhipеlago, Gal6pagos finсhеs,З5' 1 t90f, 595,6t5,669-6 Ga16pagostortoisеs,8_9 G а l е ,Е . ^ ' , 2 1 7 f Galton, }-ranсis,340_34 597-599, 80 1, 862 Gamе thеory, з41_з42' 853 Gap thеоry, sсiеnti{iссrс 84t-842 Garstang, \й/altеr,214 Girtnеr, Сar| von,729, Gаsman, Daniеl, 626 G a u s е ,G . F . ' 6 7 1 Gautiеr' Еmilе, 864 Gaylord, Gеorgе, 334 Gе$еnbaur, Сarl, 519, 6 Gепеrа Plапtаrum (Ltnn C епеrellе Мсlrphсllogiе с (Haесkеl)' 623' 828 Gеnеs/gеr"rеtiс s, 220-221 аssimilation,898; bас (]аstlе аnd, 469; Сava 47247З; Darwin's tht sеlесtiоn аnd profеssio ..sе З2_35; Dаwkjrrs's 853-854; еvolutionar mеntal thеoгy аnd' 21 tЬ.."^t,

)9].

o"nрti,-

.

Вaf' В5f; gеnеtiсhit Нoх, 222-225,223f;r l o g е n yo f , | 4 з - 1 4 4 , 1 and pаralogs,585;ph l utionаrythсlughtand morрhism,'587;rасеа Seеаlsrl Сompаrativе1 Еvolutionand dеvеlo Grеgсlr;Molесulаrdе nеtiсs;Мсllесulaгphy Phylogеnеtiсs Gепеs iп Сoп|liсt:Thе B SеlfishСепеtiсs(Burt 890 (}епеsisFhod, Thе ('WЬ M o r r i s ) 'З 5 9 ,з 7 з , 4 2 Gеnеtiсalgоrithms.Sсс J

сomрLlting and gеnеti(

Iпdeх tingasymmеtry' 930-93l ,awrеnсе'549 rгrlann,622 v l . ,1 0 0 ifera,691 J a m е sD а v i d ,9 1 7 ,dеnmorphologiеs,.' 216 \llan,701 dmundBrisсo,32, 34f, 314, 5 3 1 - 5 3 2 5, 8 6 * 5 8 86, 6 0 , 6 6 5 , 930 ,' I.' з49 ld funсtion,299, 609. Sсеаlsсl giсal forпrs аd Fuпсtioп(Russеl[). 588_590 Ъssilrесord:аdарtаtiоn,106; ;iz'sfish'405f,Ьaсtеriа,438; :ssShalе,45946З1 Соpе and, 187;in С. Darwin'stlrеory, ), |8f; Е. Dаrwin and, 509; ' i t y t h е o r i е s8.5 ;е а r l i е spt o s s i '0l е a г l yе v o I u t i o n а tr hу o r r g . h.t3.; tion of languagе, 564;gill arсhr ossiсlеs'аnd jzr'"vs lrdаptаtion, |21.,|1,8_1 1,9f; hrrmzrrl еvolution , 256_25 8, 261_26З' 268-270 ; ' s ,6 5 7 _ 6 5 86' 5 9 ;J а b l o n s kai n d , 562;marine,87,.582;Marsh 71з, 7 14f' 715;miсrсlеvolution naсroеvolutio n, 126- |291 pa|еo. q u a l i t yo f , 9 8 - 1 0 1 ; a n d sy mbrianpеriod,775-784' 777f' 7-9f' 780f' l8| f . 78.si:spесill203;taphorrornу' 879_881.See -ivingfossils;[-uсv ' t ,М i с h е l , 4 9 9 tion for Thought аIrсlЕthrсs | ,з 7 7 r-еffесtmodel of spесiatiсlrr, 202-20З,477 r-FIusТ h h е o r yo f S p е t . i l r t i о n , Nigеl,307' 308 п Еuolues(Dеnnеtt), З27 )igmоnd,,624f Karl Rittеrvon, 54l, 59\-592, 888,889 113414 es.SeеDrosophilа ; ,5 7 7 usе:Thе Sprеаdof ЕхcеlIепсе Plаto to Dаrшin (S.J. Gorrld), ТДe(pаrnphlеts), rcrttаls, .]58

FЙr Dаrшiп (F. Мnllеr),623 Fиturеof Lifе, Tbе (Е. O. \X/ilson)'925 Gаbriеl'Wilfriеd'70 l Cаia hypotlrеsis' .576,7 |з, 874_875 4.]4 Galin' Fеrnandсl, GalipagosArсhipеlаgсl, 506, 593-597 G а 1 6 p а g of isn с h е sз, 5 , | 2 7 , 1 2 8 ,1 8 9 , 1 9 0 i . 5 9 56, 15 , 6 6 9 - 6 71 , 6 7 0 f Gal6pagostortoisеs'8_9, 12f G a l е ,Е . ^ ' , 2 | 7 f Galtсln,Frаnсis,340_34l, 544-545, 5 9 7 - 5 9 9 t, i 0 1 ,8 6 2 Gаmе tlrесlгy'з4 |_з42,4 10' 599-600'

8s3

Gap thеory, sсiеIrrifiссrеаtionism and' 84t-842 .lOИaltеr, 2 l4 Garstang, G:irtnеr, (Jarl vorr, 729, 730 (iasmаn, Daniеl, 626 Causе,G. F., 671 Gautiеr, Еmilе, 864 Gavlord, Gеorgе, 334 G е g е n b a r - rСr 'а r l ' . 5| 9 , 6 2 з G епеrа P lапt.lruпI(Linnаеr-rs), 6B6 Gепеrеllе Моrp|lologiе dеr Оrgапismеп ( Н a е с k е l ) ,6 2 3 . 8 2 8 Gеnеs/gеnеtiсs, 220_22|, 5 49, 5 87 ; a ч s l r n i | а t i r э8l t9' 8 l h a с t е r i а 4 , Зl438: Сastlе ar.rd,469; Сavalli-Sforza and' 472473; Darwin's thеory of nаturаl sеlесtior.r and pгtlfеssitlnаlsсiеnсе, З2_35; Dаwkjrls.s..sсlfish,''.512, 85З_8.54;еrкllurionаryvеrsus dеvеlopmеntal thсоrv and, 279-221 genе thеrapy, 29.i; gerrеtiссodе, 132-136, 13af' 135f; gеnеtiс hitсhhiking, 722; H oх, 222-_225,223f,. rnolесulаr phy. logеny of, |43_|44,145f orthologs and paralogs,58.5;philosophy of еvo. lutionary thought аnс1,314_3-l 7; polymorphism, 5ll7; rасе апd, 822_82З. Sсс аlg, Сomp:rrзtir'ер1еlltlllliсs; Еvolution аrrd dеvеloрmеnt;Меndеl. Grеgоr; N,lolесr-rlar dеvеlopmеntal gеnеtiсs;Molес[rlirrрhylogеnеtiсs; Phylсlgеnеtiсs Cепеs iп Сoпfliсt: Thе tsiologу rlf Sеlfish Gепеtiсs (Burt and Trivеrs)' 890 Gепеsis Fkхld, Тbе (WhitсomЬ and Мorгis)' 3.59' 37.], 428,842Gеnеtiс аleоrithms. Sсс Еvolr'rtiоnату сOmpLltil1!lllttс1gеrrеtiсalgorithnrs

Gепеtit:аlTheorу of Nаtural Selectitlп, T h е ( R . A . F i s h е r )5' 8 0 , 5 8 1 , 601-602,802,804, 856 Gеttt,tic Bаsis tl| Еutllutiсlnаrу, Сbапgе,

ТДс (Lеwontin), 602-603, 683, 684, 907-908 Gеnеtiс drift, 32, 477478: gеnomе еvolr.rtionand, 153; Ohta and,767; sеl-lеsсеnсе'569; spесiation, 201-2О31 Wright and, 594 Gеnctiсs аnd АпаIуsis of Quапtitаtiuе Тrсlts (Lvnсh аnd \Walsh),701 Genеtiсs dпd thе Оrigin of Speсiеs ( D o Ь z h a n s k y ) ,3 2 , 5 2 j ' 5 2 5 , . ' 2 8 , -561,603-606, 878, 892, (]епеtiсs сlf Сoklпiziпg Spесiеs (StеЬЬins аnd tsakеr),872 Gеltеtiсs of l7umап Populаtioпs, The (Саvalli-Sforza),47З Gеnetiсs of thе Еuolutioпаrу Prсlсеss (DоЬzhansky)' 605_606 Gеnсlnlе еvolution' |52-17 6: adaptation sтr'rdуаnd' 129; сoding and nonсoding sеquеnсеs'i57-1.58; gеnе dupliсаtiсln and loss, 156f |6|-1'621gеnеtiс пratегial, l.53_154' 154ft gеrrеtiс trrаtеrial,organization of, |54-1 57, \55t' 156f' 1.57f,gеnomе additions, 160_16\ ; gеnomе.siZееvolution' 16з_164, I66f; mutation rаtеs, 164_165 1 nonсoding rеgions' gеnomе sizе atrсl,1,65-167;n
961

962

lпdeх Gеrmplasm,909 G е r s h е n s o ns ,. М . , 4 8 3 , 8 8 5 Gеstural.origins hypothеsis, of languаgе еvolutitln,565_566 Giеsеl,Tеd,479 Gill arсhеs,аdаptationand, 11,6-|21, 1 1 8 - 1 1 9 f 2' 1 З Gillеspiе,John H.' 607-608 Gilpin, Мiсhaеl,675 Gingko tree,691 Gish, Dr"ranе T ', 428 Gmеinеr,John, 354 God Delusiсlп,Тhе (Dawkins),44, 513 .!Иolfgang von, 332, Goеthе,Johann 609410,929, 952 Goldsсhmidt,RiсhardBеnеdiсt,219, 221,610-61.1,877 Gоodman,NI.,257 Goodnight'Сharlеs'900 Goodriсh,Е. S.,465 Gossе,Philip Неnry, 357, 362 Goudgе,Thomas,551 Gould' loЬn, I2f Gould, StеphеIr laу, 44, 6||-615, 61зf' 7 5 9 , 9 1 6 ;A г k а n s a sС г е a t i o nT r i a l , 428' 6|4; сhanсе,478; Сhаrlеsworth arrd,480; сlnDobzhansky,606; еvolutionaгyрrogrеss'551' 554; Goldsсhmidtаnd, 610;Haесkеiand, 626; Ьeterochronу, 214i Lеwontin and,,283, 683; miсrсlеvo]utiоn arnd maсroеvolutio n, 1'26-129 ; Ontogеlly and,214, 6 |z, 770, 771-77З: philos. ophy of еvоlutionarythсlught, 3 | 7 _ 3 | 8 ,З 2 7 ;P i l t d o w nМ a n , 8 8 1 ; Raup аnd, 824-825; rесapitulation, 829fi Sеpkoskiand, 854;Simpsоn and, 861; soсiеty'334_335; Thompson and,768-770. Sееаlso PunсruatеdеquiliЬrium Grаdualism,З 14-з1,7,334_335'6 12 Grаtnnшr of Scieпce,Tbе (К. Pеirrsоn), 800-801 Grant, B. Rosеmary,789' 595' 596f, 615-616, 671 Grant, Bruсе,654 Grant, PеtеrR., 35, 189, 595,596f, 615-616,671. Grant, RobеrtЕdmond,7,616-677 G r a u r ,D . , 1 0 1 G r a y ,A s a , 2 5 , 2 1 1 ,3 4 9 ,3 - 5 85, 0 6 , 61.7-6t8,905 Gray, Russеll'320 Gray trееfrogs,200-201' 202f

Grеat ArrrеriсanIntеrсhangе'З7_З8.

37f,4s0

Grеаtсhаin of Ьеing.SeeСhain of bеing ..Grеаt Stiпk,'' 27f

Grееks,1-2 .W' Grееn, H., З62 Grеgory of N,vssar, Saint,354 Griffin, Donаlс],.54.] Griffiths,PauI,З2О,З27 Gronovit.ts, Jan Frеdеrik'875 Group sеlесtion, 408_409'6|8_621', 7^) 9))

Groшth of tsiсllсlgiсаl Thought,Thе (Мaуr|,726 Gruпdziigееiпеr Thеoriеdеr phуbgепеtisсheпSуstепlаtik(Hеnnig),6.32 G u е r o n ,S . ' 2 4 9 Guppiеs,аdaptаtiоnand' 109, 11 1' l 13 Guyot,Arnold, 358 Gyпrniospеrms.SeeSееdplants Haесkеl,Еrnst,25, 26, 257, 622-627, 624f, 772, 828;bipеdalitу,269; Huхlеy and, 650;rесapitulation, 2l0, 2 1 1 f ' 2 1 4 ' 2 1 ' 5 s; o с i е t y3, 3 3 ' 3 3 6 Haесkеr,Vаlеntin,832 Нaigh, Johл' 722 H a l d a n еJ, . B . S . ,3 1 , 5 0 , 3 1 4 , 4 1 ' 6 . 4 7 1 4 7 2 , 5 6 1,f 6 2 7 - 6 2 9 , 7 7 4 ; сhanсе,477; СЬеtverikovand, 483; Мaynard Sпith and, 720-7213 postzуgotiсЬarriеrs,185-186;Wгight and,927,928 H a l d a n е ' ds i l е m m а5, 7 З ,6 2 9 Нall, G. Stanlеy,829 Н a l l , Н е n r yМ o n r o е , 4 8 4 Hallam,Arthur,474, 894-895 I7аlluсigепiаspаrsа'460, 461f, 462f Hamilton,W. D., 239, 244, з41_342' 4 0 з , 4 0 9 , 5 6 8 '6 2 9 - 6 3 1 6 , 60,865' 890,921 Hаmilton'srtrlе,6З0 Hansеn'Anrra'485 Нardy, Alistеr,465 Нarеm.dеfеns e po|уgуnу,241 Наrpеr,D. A. T.' 81_82 Harrold,F'.8., 373 Haught'Jсlhn,882 Hausfatеr,Glеnn,643 Hаiiу' Rеnё-Justе, 606, 607 Нawаiianсriсkеts,199 Hаyеk, FriеdriсhA. von, 864 H е d g е sS, . B . , 1 0 1 Неdlеy,Jоhn, 353

Hеfпеr,Philiр'8ti2 Неgеl,Gеorg..3З2 Hеmoglobin,14з-141 Hеndеrson,L-.J.' 562 Hеnnig, \)(/illi'26:l' 63 Hеnslow,JоhrrStеr.е HеrеditаrуGеnius(Gi 5 4 4 ,5 9 7 ..НеrеditаryТаlеrrtэnt (Galton),.S97--S9 оf: lа Hеrеdity,thе
Hеreditу аnd Нulll,tп 1 Hеreditу, Ritсt,'апd Sс DоЬzhаnskr'),.S24 Неrmеnеutiсs,.362 Hеrsсhеl,john Ь..W.' . Неrtwig, Osсar, 622 Hеrt''ilig, Riсhаrd, .591 Hеss, Саr1 von, .i9l Неtеroсhromatin. l.58 L67 Hеtеroсhronv' 21'o'zI 6|1-612,772_77з Hеtеrоtсlpy,210 Hехаpodа. See Insесts H i е s е y ,W i l l i a m , 4 8 4 _ Hintоn, Martin A. С.' Hirаzumi, YLriсhiго.4[ H i s , W i l h е ] m ,6 2 6 H istоirе tшtн rс llс, gёп и/lёrс (Buffon),455, Нistoriа Plапtаrum \R Нistoriсal homology, ( Historу апd Gеogrаph Geиes (Саvаlli.Sfor Hisfulrу сlf АпimаIs \А 424-425 Нistory of lifе. Sсe Еvс tоriеs; origin
6з5f

Iпdeх

\mеriсanIntеrсhangе, 37_З8, 450 :hainof Ьеing.SeeСhain of bеing Stink," 27f 11

w.H'з62

y of Nyssa,Saint,З54 , Donald,543 LsP , a u l ,3 2 0 , 3 2 7 lius,Jan Frеdеrik,875 sеlесtion,408-409, 618-62|, 922 ,Гhe b of BiologiсаlThought, trl,726 ,'йgeеiпеrThеoriеdеr phуlo|isсben Sуstеmаtik (Hеnntg|,6З2 ц S.,249 s , a d a p t a t i oann d ,1 0 9 , 1 1 1 , 1 1 3 Arnold,358 )spеIms.SeeSееdplants ll, Еrnst,25,26,257, 622-627, 269; ' 772, 8281Ьipеdality, еy and' 650;rесapitulation, 210, soсirty'з33, 336 ' 214, 2151' r, Valеntin'832 lohn,722 е ,J . B . S . ,3 1 ' 5 0 , з 1 4 , 4 | 6 , 472, 561f, 627-629, 774; сe,477; Сhеtvеrikovand, 483; l а r d S m i t ha n d .7 2 0 _ 7 2 ;| ;ygotiсbarIiеrs'185-186;!Иright 927, 928 е ' sd i l е m m a5, 7 3 , 6 2 9 . Stаnlеy,829 |еnryМonroе' 484 , Arthur,474,894-895 gепiаspаrsа,460' 46If' 462f .W. o n , D . , 2 З 9 , 2 4 4 ,з 4 1 - з 4 2 , 4 0 9 ' 5 6 8 '6 2 9 - 6 З 1 '6 6 0 , 8 6 5 , 921 on'srulе'630 , Anna,485 Alistеr,465 .dеfеnsеpo|уgуnу,241 , D. A. T., g1-92 l, F. 8.,373 :,John,882 rеr' Glеnn, 643 3.еnё-Justе, 606, 6О7 an сriсkеts'199 FriеdriсhA. von, 864 , s . 8 . ,1 0 1 , John,З53

Hеfnеr,Philip' 882 Hеgеl,Gеorg,.332 HemogloЬin,|4з_144, 145f' |46f Hеndеrson'L. I., 562 Hеnnig,Willi, 261, 632-6з4' 840 Hеnslow,JolrrrStеvеns, З57 НеrеditаrуС епius(Galton),340*з41' 5 4 4 ,5 9 7 ..Hеrеditary Talеntand Сharaсtеr,' ( G a l t o n )5, 9 7 - 5 9 8 Неrеdity,thеoryof: laсkingin Darwin's thеoryсlf naturirlsеlесtion,25_26; Mеndеl and, 30_32;philosophyof еvolutiсlnary thought'319_320;soсiеty аnd еvolutionarv thought, 333-334,338-342 Hеrеditуапd Humап Lifе (Сarson),467 Hеrеditу,Rасе, апd Soсiеtу(Dunn and DоЬzhаnsky)'524 Hеrmеnеutiсs, 362 Hеrsсhеl,Jоhn F. W.' 3.51,916 Hеrtwig,oscar,622 Hеrtwig,Riсhаrd,59l, 610, 622, 909 Hеss,Саrl von, .591 Hсtеroсhromаtir"r, 158-] 59, 162, 166, 167 496, Hеtеroсhrony, 210, 2-13_215, 611-612,772-773 Неtеrotopy,2l0 Hехapоdа.SсeInsесts Hiеsеy,William, 484-485,872 H i n t o n ,М а r t i n A . с . ' 8 l 3 Н i r a z u m i ,Y u i с h i r o4, 8 9 His, !Иilhеlm,626 Histсlirеnаturеllе,gёпёrаlе,еt pdrtiсuliёrе (Bfifon)' 45.5,4.56/ HistoriаPlапtаrиm(Rаy)'827 Historiсalhomo|ogy'638 Histсlrуапd Gеogrаphусlf Нumап 472_47з Gсиes(Сavalli-Sforzа), Нistorу of Апimаls (Aristotlе), 423, 424-425 Нistory оf lifе.SсeЕvolutionof lifе histоriеs;С)riginof lifе Historу of thе Сопfliсt bеtшсеп Rеligiсlпапd Sсiепсе(Drаpсr),350 Historу сlf tbе lпdисtiuеSсiепсеs (\Иhewеll), 9 1'4,9 1'5, 9 |7 Historу of thе Wаrfаreof Sсiепсеtuith Thullсlgу in Сhristепdсlm,А (А. Whitе),3.51 I-ilV, 282, 286-287 HoЬЬit (Н omсlflorеsiепsis), 6з4-6з6, 6з5f

Нoсkеtt, Сharlеs, 562-56з Hоdgе, Chаrlеs, 357 H o l l a n d , . | o h n ,5 4 9 HolldoЬlеr, Bert, 924-925 Holloway, Aliсia, 201 Holmеs, Olivеr Wеndеll, 546 HоlоmеtaЬolous insесts,658 HоmеoЬoх,221 Нomеotiс gеnеs. Sее Floх gеnеs Homеotiс mutations' 219-22\, 220f Homologous amino aсids, 40/ Homology, з, 4f, 19, 212-213, 6О7, 636-638,915; Agassiz and, 404405; Hеnnig and, 633; morphologiсal сriterta,636_637; owеn's usе of tеrm, 272. See a|so Nаturpbilosophiе Homoplasy, 260-26'1, 264, 497 498, 808-809 Hoисl spесiеs еvolution, 258_259t'

260f,264-272,696 Hookеr,JosеphDalton, 349,448' 506, 638-6З9 ..Нopеfulmonstеrs,'' 219, 221, 6|1 Horizontalgеnеtransfеr,438,440 Hormonеs,soсialbеhаviorand,249 Нorsеs(Simрson), 860 HorsеshoесraЬs'690 Нorsеtails,690_691 Host paтasitееvolution,640-642 Нovind, Kеnt, 375 Hox gеnеs,220-225,223f,495496, 789 Hrdy, SarahBlаffеr,642-64з Н u b Ь y 'J . L . ' 5 2 8 ' 6 0 2 ' 6 8 З Н u Ь е r ,с . , 5 9 ' 6 з Hull, David' з22, 8з9-84| Human Ьеhаvior.SсeSoсialЬеhavior; Soсiеty Human еvolution,256-280; Afriсan dispеrsаl,266_268,694, 695-697; Ьipеdаlism, 26з-264, 269_271, 694, 696,,Ьrain,256, 258_259t,260f, 266' 268-269,271-272; еarlyhоminins, 27|_272,, 26|-265; futurеrеsеarсЬ, Homo speсiеsorigins,258_259t' 2 6 | _ 2 - 2 \h u m а n sp. l а с еi n n a t u r е . 256_257, 260-261,26Ofimastiсation and diеt,271 Humаni G епеris(papalеnсyсliсal), 35.r-3.56 virus (HIV), Hurтan immunodеfiсiеnсy 282,286-287 Н u m е ,D a v i d ,4 - l 0 ,7 9 9 , 8 0 0 , 9 2 5 Нumphrеy,Niсholas,407

96з

964

Iпdeх Нuntеr,Gеorgе,846 Нutton' Jamеs,643_645' 816 Нuхlеy,Aldous,628 H u х l е y 'J u l i a nS . ,3 2 , з з , 6 4 5 - 6 4 9 ' 770; Bеrgsonand,446447; еvolutionarypfogrеss'551; Ford and,587; Laсk and' 669-67О1Simpsonand, 861; soсiеty,334; synthеtiсthеory, 547-549;. Tеilharddе Сhardin and, 882 Huxlеy' ThomasHеnry,4f, 25, 26, 41, 5 0 6 ,6 1 . 6 6, 4 9 - 6 5 1 , 7 1 0 - 71 2 , 7 1 1 f ; Darwin and, 514; dinosaurs,519; е v o l u t i o n a rpyr o g г е s s2.5 6 - 2 5 7 ,5 s l . 696' 744;Haесkеland, 623;Мarsh and,7I4f, 715; OsЬorn and,79З; r е l i g i o na n d ,з 5 1 , 3 5 2 , 6 5 1 ;s o с i a l Darwinismand, 864;soсiеtyand, 336; Spеnсеrand,867;Whеwеlland, .!Иilbеrforсе 917; and, 348, 920_921,

Informationаlmaсromolесu\es, 136_1З7 Inhеritаnсе.Seс Hеrеdity,thеoryоf lпhеrit the V/iпd (film),371, 846 Innatеspесiеs-spесifiс Ьеhaviorpattеrns' 692-693 Insесts,88f' 89' 656_660;еvolutionaтy study,660; flowеringplants, 65 8-659: pollination,849-850; sоngs'406. Sееаlso speсffiсiпsесts IпsесtSoсiеtiеs,Thе (Е. C).!Иilson)' 865,924 Instinсt,17, 1'8,18f,37, 541_542 Institutеfor СrеationRеsеаrсh(IRС), 3 7 3 ' з 7 4 _ з 7 5 ,3 8 4 , 8 4 1 Intеlligеnt Dеsign(ID)Thеory,45, з6з, 37 5-з84, 7 59, 844;аdaptationand, 114-115;'as ..altеrnatе sсiеntifiсthеorу,',З75-376;аttaсkson Dаrwin, 514_515;сontеnto|, З78-З79;сreаtion sсiеnсесomparеdwith, 378' e20f З80;as сulturalrеnеwal,З82-З84; Нuygеns,Сhristiaan'759 еstaЬlishing of movеmеnt,З76_378; Нybridization sсiеntifiсmеthodand sсholarship, , 729-7з|, 876 Нydrothеrmalvеntsthеoryof origin of з79_384 l i f е ,5 8 _ 5 9 ,6 2 , 6 8 _ 6 9 ,5 7 6 Intеlligеnt DеsignNеtwork (IDNеt), Hygiеnе,еvolutiоnaryЬiology of disеasе 388 and,290 Intеraсtоrs, 728, 8З9, 840_841 Нypеrсyсlе,533 Intеrсеllulаr pangеnеsis' 896_897 Intеrgеniс sеquеnсеs' 157_158,160' Ibis skеiеton,501/ 163, 1.64,169-170 ldепtismus,832 lпtroduсtЙlnапd Sиссеssklnof ..ImpaсtSummеrs,''53-54 vеrtеbrаtеLifе iп Аmeriса, Thе I m p r i n t i n g3,2 0 ' 5 8 3 ,6 9 З , 8 8 9 ( M a r s h ) 7, 1 . 5 Inсlusivеfitnеss,2З9, 890 Iпtroduсtioпto PopulаtiсlпG eпetiсs Indеpеndеntrеpliсators'in history оf Theorу,Ап (Сrow and Kimurа),489 lifе thеoriеs,83 Iпtrogressiuе Hуbridizаtioп (Andеrson), lпdiсаtirlпsof thе Сreаtсlr(Whеwеll), 4'15 894,914 I n t r o n s1, 4 7 , \ 5 4 f , 1 5 7 - 1 5 8 1 , 60, Indigobirds,l94 16з*\64,169_17з Iпdiuiduаliп thе Aпimаl Кiпgdom' Thе Iqbal,Мuhammad,361 I r i d i u m ,4 1 1 , 7 1 6 [. S. Huxlеy), 447, 645 Individualism, philosophyof еvolution- Irishеlk, 42l а r y t h o u g h tа n d ' 3 l 4 - 3 l z IrrеduсiЬlе сomplехity(Iс), 363, Individualsеlесtion, thеoryof, 619' Sее з 7 9 _ 3 8 0 '3 8 ] . з, 9 З , 75 9 аlso Ьdaptation;Nаtural sеlесtion Isаaсs,SamuеlМ.' 360 Industriaimеlanism,109, "112, I s l a m ,3 6 1 - 3 6 2 ,3 6 3 652-656,653f,665-666 IsolatingЬarriеrs,spесiationand' IndustrialRеvolution,еvolutionary 1 8 2 - 1 8 6 , 1 8 3 r1, 8 5 / thoughtand,4-5,5f Isolationand divеrgеnсе' DoЬzhanskv Iпfапticide:Сompаrаtiuеапd and, 604-60-5 Еuoluti oпаrу Perspeсtiuеs (Hаusfatеr Ivеraсh'Jamеs,3.57 and Hrdy), 643 Infantiсidе, Hrdy and, 642-643 JaЬlonski,David, 661-662 Influеnzavirusеs'285. z91' 58.5_586 851/ Jaсk-in-thе-рulpit,

Jaсkson'J. B. С.' 96_97 Jaсob' Frangois,121 JanaЬiT , . F { . ,3 6 l F. A., 750 Janssеns, Jarmаn,P. J.' 242 Jaws,adaptationand, 118 Jеffrеy,Е. с., 871 Jеllyfish,613/ Jеnkin, Hеnry СharlеsFlе 662-664 Jisr, Hossеinal-,361 J o h a n n s е nW, i l h е l m4. 8 4 John Paul II (popе),356 J o h n s o nP' h i | | i p4. 5 ' з 7 7 , Jonеs,John Е,.,III,393 loиrпаl оf Gепеtics,627 lourпаl of Litеrаturе,Sсiе 474 Joyсе,G. F., 68 Joyсе,Riсhard, 321 J u d a i s m2' , З 6 0 - 3 6 1 ,з 6 5 Jukеs,Thomas,666 J u s s i е uA, n t o i n е - L а u r еt Jussiеu'Bеrnarddе,502

Kаl ksсhtl,iimmе, D iе (Fl.a K a n s а sа, n t i е v o l u t i o n i is Kant, Immanuеl,510' 609 Karyomаstigont'539_540 Kasting,J. F., 53 K а u f f m a nS. t u a r t3. 0 9 ,4 4 Kесk, Dаvid' 484485' 8i Kеimplаsmа (.VИеisman K е i t h ,A r г h u r ,3 5 9 , 6 7 7 I. Kеkulё,Friеdriсh,382 Kеnсе,Aykut,361 KспуапthropusplаtуОРs. Kеnyon, Dean,377 K е t t l е w е |Hl .. B . D . . 3 2 . I 652-653,665-666 Kеy, WilhеlminеЕntеma Kihara' Нitoshi,668 Kimura,Мotoo, 478,489 -67,90 666-668,766, King, Jaсk,666 K i n g s l е yС. h а r | е sJ'5 6 ' 6 , Кin sеlесtion'125' 341_з 6 6 0 , 7 2 з , 8 6 5я,9 6 . , 1 409; soсialЬеhaviorаn Kinship сoеffiсiеnt'239 K i p l i n gR , u d y a r d4. 1 .4 3 KirЬy, Hаrold,Jr., 540 Кitzmillсr u. DсluеrАrcа ! Distriсt, 392_з9з

Iпdех tional maсromoiесulеs,136_1 37 nсе. See Еlеrеdity, thеory of I h с W i п d ( f i l m ) ,З 7 l ' 8 4 6 pесiеs-spесifiсЬеhavior pattеrns' '9З 88/' 89' 656-660; еvoluгionагy , 660; flowеring plants, 559;poliinаrtion.849_850; ,406. Sее аlso spесifiс iпsесts tlсiеtiеs'.Гhе(Е. O. Wilson),

)24 7 7 ,| 8 , t 9 f ,З 7 , 5 4 \ _ 5 4 2

l for Сrеаtion Rеsеarсh (IRС), )74*З75'384,841 nt Dеsign (ID) Thеory' 45, з6з, \84, 7 59, 844; adaptation and, [ 15; as ..аltеrnаtеsсiеntifiсthеo. 75-З76; attaсks оn Darwtn, l |) i с o n t е l l to I ' J / U - J / Ч ; с r e sсiеnсесoпlpаrеd with, 378, ts сultural rеnеwal, 382-384; l s h t n go t m o v е m е n t ,3 7 6 _ 3 7 8 l ' ifiс nrеthodaпd sсholarshrp, i84 nt Dеsign Nеtwork (IDNеI), trs,728,839,840-841 ular pangеnеsts,896*897 l с s е q u е n с е s1' 5 7 - 1 5 8 , 1 6 0 , t64,169-170 :tion апd Suсcеssiсlпof lrаte Li|e iп Аlllеriса, Thе h),715 .titltt trl &lpulаtioп СепсIiсs ,J',Аtt (Сrow and Kimura), 489 ssit'е Нуbridizarioz (Andеrson), 147, t54f, 157-158, 760, 64,1'69-17з luhammad, 361 4 1 1 ,7 1 6 4'' {

э l ес o m p l е х i t (yI с ) ,3 6 3 , ,80,381,393,759 a m u еМ l .,360 5 | _ З 6 2 .3,6 З ; barriеrs'spесiationand, 8 6 , 1 8 3 r ,1 8 5 / r and divеrgеnсе,DoЬzhаnsky ,04-605 . l а m е sJ' ) / :i,David,667-662 hе-pulpit,851/

J a с k s o nJ, . B . С , , 9 6 - 9 7 JасoЬ,Frаngois,1) l J a n a Ь iT , . H.' 361 F. A., 750 Janssеns, P Jarman, . 1.,242 Jaws,adaptationand, 118-119f'2\з Jеffrеy,Е. с., 871 Jеllyfish,613/ . l е n k i nH . е n r yС h а г l е sF I е е m i n c ' 662-664 Jisr, НossеirraI-,36| \JИilhеlrn, 484,749 Johannsеn, John Paul II (popе)'356 Johnson,Philliр, 45,377, з79, З8з-з84 Jonеs,John Е., III,.]93 lourпаl of Gепеtics'627 Jourпаl of Litеrаturc,Sсiепсеапd Arts, 474 Joyсе,G. F., 68 Joyсе,Riсhard,321 J u d а i s m2, ' 3 6 0 - З 6 l ' 3 6 . 5 Jukеs,Thonr:rs,666 dе, 681 Jussiеu'Antoinе-Laurеnt Jussiеu,Bеrnаrddе' 502 Kаlksсbtuijmme,Die (Haесke|\,625 Kansas'antiеvolutionism and, 386_388 Kant' Immanuеi,5 10, 609, 681, 91'4 Karyomаstigont,539-540 Kasting,J. F., 53 Kаuffman,Stuаrt,309, 447,613f Kесk, David' 484485' 872 К еimplаsmа (.WеisтnirnIr), 333_з34 Kеith,ArtЬur, з5L),677, 812 Kеkulё,Friеdriсh,382 Kеnсе'Aykut, 361 Кenуаntbropus p Iаtусlps' 260f' 264 Kеnyon,Dean,377 К е t t l е w е lН l , . B . D . , 3 2 , 1 0 9 ,5 8 8 , 652-653,665-666 .Wilhеlminе Kеy' Еr-rtеman, 927 Kihara,Hitoshi,668 K i m u r a ,M o t o o , 4 7 8 , 4 8 9 ,5 7 3 , 6 0 2 , 6 6 6 - 6 6 8 , 7 6 6 , 7 6 79. 0 8 King, Jaсk, 666 Kingslе1', Сharlеs,3.56,6.50 Kin sеlесtion,\2'5,з4|_з4z, 40з, 6з0' 6 6 0 , 7 2 з ' 8 6 5 ' 9 0 0 ;а l t г u i s ma n d , 409; soсialbеhaviorand,239_246 Kinshipсoеffiсiеnt, 239 Kipling,Rudyатd,41',43f Kirby, Harold,Jr., 540 Кitzmillеr u. Douеr Аrеа Sсhoсll Distriсt'з92-З93

Kl6сеl' N,IаtouЁ, 730 Knuсklе-rvа[king' mystеryof, 272 Kohlеr,Kaufmаnn,360 K o h n ,D a v i d ,5 1 7 Ксljima'Kеniсhi,607, 767 Kolrеutет,.|osеph,729 K o l , t s с l vN' ' K ' ' 4 8 2 ' 8 8 5 Kondrashоv,Alех, 701 Kovalеvsk,v' w' o'' 622 Koza, lohn R., -549 Krаrrskopf, Josеph,360 Krеitm:rn,Маrtin' 682 Kropotkir-r, Реtеr,29, 864' 885 -.55 K u h n .Т h . ' m а s3, 2 5 , K u m a r ,S . , 1 0 1 Kummеl,l}arnhard,824, 854 Kuypеr,AЬraham'363 l,aсk,David LаmЬеrt,567-569, 595, 669-672 Laсk ClutсlrSizе,.567_.568 LаHzrуе,Tiгл,372_З7З Laissеz-f:rirе liЬеrаlisni,29, 5 14, 862-864,867 Lakatсls'Imrё'325 Lamаrсk'Jсаn-Baptistе, 3, 442, 672_675, 742, 9З2_9З4;Ьipеdаlity, 2691сЬancе,476;Сuviеr and, 500, pIogrеss'550; Lyеll .502;еvolutionary and,699, 8 19, 894 naturalhistory, 754 Lamarсkisпr,.]' 2.', 486-487,507, ''10, 867 Lаnсеlеts'789-79| Lirndе'Russеl|,196, 480,675-676' 70 | L:rnеssarr, J.-l-.dе' 864 Lаng' Andrеw,622 Languаgе: of Ьееs,591; in historyof litе thеoriеs,84; soсialЬеhaviorand,252. SееаIsсlЕvolution of languаgе I'апgursсlf Аbu: Femаlеапd Маlе Strаtеgiеsof Rеprсldисtiс-п' Thе ( H r d y ) ,6 4 2 Larson,F-.1., .170 L a s а l l е F, е г d i n а n d8' 6 3 Lаst сomtlot.litl)сеstor(LсA)' 68_74, 8 4 , 1 - 1 92,5 7 , 4 3 8 Lаtitпеriа' 689 Laudеr,Gеоrgе,590 L a v a r e zL. u i s , 7 1 6 Lawrеnсе,Williarn, 903 Lаzсаno,A., 58 Lеaf positions,Ьiolоgiсalformsand, 299-307' зО1'f,30Зf

с)(l5

966

Iпdeх Lсаkеy,Louis SеymourBаzеtt,676-678 Lе:rkеy,Мarу,677 L с a I ,I \ l а n u е l .9 6 Lеаlаps,5|9 Lе Bсlll,Gustаvе,862 LеСontе'Josеph,358, 90.5 Lесturеsoп СompаrаtiuеАпаtomу, Phуsiologу,Zсlrllogу,апd tbе Nаturаl Historу rlf Мап (Lawrеnсе), 903 Lеdеrbеrg'Еsthеr,679 Lеdеrhеrg,Joshua, 290, 574' 678-680 Lееuwеnhoеk, Antoni van,437 Lеhrпrzrn, Daniеl,542 Lеigh,William R., .57.5f Lеkking po|уgуnу,242. Lеo ХIII (popе)'352 l - е p i d o s a u r7s 4 ' 0,747 I,еprosy,439 L е r o y ,М . - D . ,3 5 3 i?l СОmpаrаtiuеАпаtсttttу I.,еssoпs (Сuviеr),680-682 Lеvеr,Jаn' 363 Lеvins,Riсlrarс{, 675 L е w i s ,Е d , 5 2 9 Lеwontin,Riсhard,З3l' 28.3'з.|8'479, 5 2 8 - 5 2 9 ,5 7 8 ,6 0 2 _ 6 0 з 6, | 2 , 6 75 , 682-686,907-908 Lifе historiеs.Seс Еvolrrtionof lifе histсlгiеs;Origin of lifе Lifе tlf thе Robiп' Тhе (Laсk),669 Likеlilroodсonсеpt'of Fishег,.580 L i l l i е 'F r a n k ,2 1 4 Lindiruеr,lvtаrtin..541 [,inеаrmodеlof divеrsitv,8.5'86/ Tim, 900-90l [,inksvaуеr, Litlnaеus'Сarl (сlrСarl von Linn6), 686-688,875-876 Linnё,Сarl von. SсeLinnaеus,Сarl I-ipsоn,R.' 549-5.50 Livir.rgfossils,688-692 L
Luсу (Аиstrаlсlpithесus аfаrепsis), 693-697, 695f Lumsdеn,Chirrlеs,924 L u r i а ,S а l v a d с l 6 r '7 9 L r ' с l l ,С h a r ] е s8' ' 1 1 f , 1 9 , 9 9 , 6 З 9 ,6 4 4 , 697-700, 7 10-71 l, 8 16-820, 894, 903; biogеogrаphy, 448; Darwirrand, 5 0 5 _ 5 0 67, 9 9 ' 8 1 8 _ 8 1 9r;е l i g i o na n d , 19,699 Lynсh,Мiсhaеl' 1.53,70o-7o2 [,ysеnko, TrоfiIrt'з34, 482, 8з7, 866 Lysеnkoism,628.647 Lуstrсlsаurus,149 MaсArthur,RoЬеrt,451, 924 MaсDonаld'Ilсlgег,348 МaсKay' Jоhn, 375 Мaсloskiе,Gеorgе,3.58 М a с n a i r ,M a r k ' 1 8 4 Maсroеvolutitln, 93' 126_129, 2 2 5 _ 2 2 7 4' 7 5 ' 4 7 8 ' 6 \ 2 _ 6 | З ' 869-870 Масrrlеurllutiсltl: Pttttеrп апd Prtlсеss (Stаnlеy),869_870 Мaсr.onlutirtiсlns, 21 9, 6|1, 877 Мaggot t|,-.Sее Applе mаggot Ily Majеrus, NIiсhaеI,653 Маjor Fеаturcs of ЕUОlutioz (Simpson), 860,884 Ма jоr histoсonlpatiЬilityсоmplеx (МHс), sсlсiаlЬеhаvior аnd,250 Mаlаria,43.5 MaltЬy, Dеbоralr' 479 Маlthus' Thurlаs RoЬеrt, |o, lзf, 14, з3Z, 703-704' 770, 867, 904 Мammals, 7o4-709 Мап апd Supсrmап (G. B. Shaw), З41 Мап апd thе \lеrtеbrаtеs (A. S. Romеr), 835 МandiЬulatе hyрothеsis,for сrustас е a n s '4 9 8 Мапkiпd Еuсllt'iltg(DoЬzhаnskv),524 Мanning, Hеnrv, с)l9 Мап.s Plасa iп Nаtнrе 1T. Н. Hltхlеv),

7 t 0 - 7 1 2 , l71 f

Мапuаl o|.thеBotапуof tbе Northеrп UпitеdStаtas(A. Gray),617 Маrgoliash,Еrnanuеl'584 М а r g u l i s L' y n n '4 3 9 , 5 7 6 , 7 | 2 - 7 | 3 Marinе invеrtеbrl1tеs, divеrsifiсаtiоn of' 87,88/ Mars ехplсlrагion' 787 Marsh, oгhniеl С-hаrlеs, 486, 6.50, 7 t 3 - 7t 5

M:rrtin, J. !и.' 491 Mаrtin, \и., 101 Мirrх, Kilrl, 33з, 364' 6t Маss ехtinсrions,7l.i-7. 855; сausеs,7 1'6_7 IL); 719_720. Sсe a/stlЕхti Plеistoсеnееxtinсtions N{astiсаtion. Seс Tееth Маtеriаl Bаsis of Еt,olutt (Goldsсhmidt),877 Мatеrialism, rеligion аnс з6|' 36з_з64 Маtеri"tls for thе Studу о Trеаtеd u'ith Еspcсiаl Disсtlпtiпuitу iп t|эa()

(Bаtеson),219 ,.]\lаthеmаtiсalThеory o Natural Sеlесtion,Part stаЬlе Populatrons''(H Мathеr, Kеnnеth, .529 Маthеson, Gеorgе, 3.57 Маttlrеrv, Williаm Dillеr Mахinrшrn-likеlihoodmе rtrоlесr"rhrrесonstruсti N1аrximutn.parsimсlnyt-t Inolесular rесonstruсt .'iи. D., 99 -N4аxwеll, N,laуnardSmith, John, 8, 320, 338, 479, 600,7. Ма1'r, Еrnst'W.altеr,32' з|4, зЗ4,3з9,416,4 6зз' 724-727, 832, 8[ 92З; biogесlgraphy'44 477; еl'o 466; сl-ranсе, fоrm r,е progrеss' .5.51; .590;Laсk аnd, 595; R Sinlрson and, 8.59,86 779, 187, 188f, 202-2 and,924 MсСarthy, John, 3'56 Мс(,lintoсk, BarЬаra' 75 МсСсlsh, .|аmеs,З57, З6 М с K i n n o n ' . [ е f f r е v ,l 9 1 _ NIсLеan, Rсvеrеnd Bill' . МсLеап u. Аrhапsаs BLl tirл, 373_374,384 N4сМul1in,Еrnаn, 36З .I М еапiпg сlf Еu o lиt ioп, 861 Месlrаniсal сhrсlmosom 742-74з МесkеL, .|ohann}-riеdri Mсdirrv:rr' Pеtег, 35.5' 8E NIеdiсint''Dаrwin aпсl' :

Iпdех \ustrаlсlpithесиs аfаrепsis), -697,695f еn, Сharlеs,924 Salvador,679 J h a r l е s8, , 1 1 f ,1 9 , 9 9 , 6 3 9 , 6 4 4 , -700, 7 10-71 1, 816-820, gg4, Ьiоgеography, 448; Darwin and, - 5 0 6 ,7 9 9 ,8 1 8 - 8 1 9 r; е l i g i о na n d , ;99 Мiсhaеl' 153,700-702 o, Тrofim,зз4, 482, 8З7, 866 oism,628,647 ;аurиs,449 t h u r ,R о Ь е r t , 4 5 1 , 9 2 4 lnald,Rogеr,348 Ly,John,З75 ;kiе,Gеorgе,358 ir,Мark, 184 :volution,93, 126-129, . 2 2 7 ,4 75 , 4 78 , 6 1 2 _ 6 1 з ' 870 luolutiсln:Pаttеrпапd Proсеss Llеy),869-870 n u t а t i o n s2.1 9' ь | | , 8 1 j t flу. SееApplе maggоtfly s' Мiсhaеl'653 Fеаtцrеs of Еuolutioп(Simpson), 884 histoсompatiЬility соmplеx C), soсiаlbеhaviorаnd, 2.50 I, z+J)

, Dеborah,479 Ls,ThomasRoЬеrt,10, 1Зf, \4, 703-704,770,967, 904 a|s,7О4-709 ld Supеrmап(G. B. Shaw),341 (A. S. Romеr), d thе Vеrtebrаres lulatеhypоthesis' for сrustа;,498 d Еuoluiпg(DoЬzhаnsky)''524 lg, Неnrу, 919 Plасеiп Nаture (T. H. Huхlеy), 712,7|1f l of tbе Botапу сlf thе Nсlrthеrп ,,dStаtеs(A. Gray),617 Liash, Еmаnuеl,584 [ i s ,L y n n '4 з 9 , 5 7 6 , 7 | 2 _ 7 1 3 invеrtеbratеs, divеrsifiсationof, t8f хploration,787 othniеl Сharlеs,486, 650, .715

Мartin, J. !r.' 491 Маrtin, !и., 101 Мarx' Karl, ззз, з64,684, 863 Mass ехtinсtioлs, 7 15-72О, 7 17f' 825, 855; сausеs,7 16_7191сonsес1uеnсеs' 719_720. Sее аlso Ехtinсtion; Plеistoсеnе ехtinсtions Маstiсаtion' Sсс Tееth NLаtеridl Bаsis of Еurllutirlп, Thе ( G o l d s с h m i d t ) 8, 7 7 Мatегialism, rеligion аnd, 349, З50, 3 6 1 ' ,з 6 з _ 3 6 4 Маtеriаls frlr thе Sttldу of Vаriаtioп Trеаtеd шith ЕspесiаI Rеgаrd to Disсспltiпuitу iп thе Origiп of Spесiеs (Batеson)'2-l9 ..Мathеmatiсаl Theоry of Artifiсial and Naturаl Sеlесtion,Pаrt VIII, Меta. stаЬlе Populations'' (Нaldanе), .561f lvIathеr, Kеnrrеth, 529 Маthеsоn' Gеorgе, 357 Мatthеw' William Dillеr, 858 Мaхimum-likеlihоod mеthods, of molесular rесоnstruсtion' 143' 810 Мaхimum-pаrsimony mеthods, of m t l | е с u ] arrе с O n s t r u с t i ( ) n| 4' 2 _ |4 з Maхwеll, W. D., 99 М a y n а r d S m i t h .J o h n . 8 2 _ 8 4 . 2 4 0 _ 2 4 | . 320, 338, 479, 600,720-723,923 Маyr, Еrnst \й7altеr, з2, зз, з5, 94, З\4' зз4' зз9' 416,418, 522' 671' 6зз'724_727, 832, 889, 892,907, 923; Ьiogеography,448; Саin arrd, 4 6 6 l с h а n с е '4 - 7 ; е v o | u t i о n о r у progrсss' .5.51;fоrm vеrsus funсtion, 590; Laсk and, 59.5;Rаup аrrd, 824; Simpson and, 8.59,861; spесiation, \79, |87,188f' 202'_203;!Иilson and,924 MсСаrthy' Jсlhn' 3.56 МсСlintосk, BаrЬаrа, 752 МсСosh, Jаmеs, 357, З6З, з64 MсKinnon, Jеffrеy, 19 1-192 MсLеаn, Rеvеrеnd Bill' 37З МсLеап u. Аrhапsаs Boаrd of Еduсаt l с l п ,3 7 3 _ 3 7 4 , 3 8 4 MсМullin, Еrnаn,363 Меапiпg of Еuolиtioп, Т/:с (Simpsor"r)' 861 Месhaniсal сhromosomаl spесiation' 742-74з Месkеl, Johann Friеdгiсh, 209' 442 Mсdаwar, Pеtеr, З55' 882 Mеdiсinе, Dаrwin аnd, .514-51.5,.544.

Sееаlso ЕvolutionaryЬiology,of disеasе Меgаlosаurus, 5 18, 519 Меgаthеriиm,5ОО Меiп Капpf (Hitlеr),515 Меlvillе,Hеrman,593 MеmЬranеs,сhеmiсa1rеpliсationand, 66-67,534--t35 M е m е ,2 5 2 , 5 1 2 , 5 1 З , 7 2 7 - 7 2 8 ' 8 5 3 - 8 5 4 ,8 7 4 Меmеtiсеvolution,853-8.54 Меmсlir oп tЬе PеаrlуNаutilus (owеn), 795 Mеnсkеn,H. L., 651, 845 Меndеi,Grеgtrr,з0-З2,31f, 515, 728-731,7з0f, 802' 85О.Sеeаlso Gеnеs/gеnеtiсs Меndеliangеnеtiсs'30, 45, 219,470, 482, 484, 516, 594, 601-602,663, 7з1, 755, 772, 804, 892 Mеndеlson'Tamra,199 Мепo (P|ato),423 Меп tlf thе Оld StoпеАge (Osborn), 79з Mеrеzhkovsky'KonstаntinSеrgiviсh, 712 Mеrtеnsiаnmimiсry, 7З8 Меrtrud,Jеan-Сlaudе, 680 Еrnеst,354_355'364 Меssеngеr, 796 Меtagеnеsis, Меtеoritеs.SeeЕхoЬiology naturalism'383 tr4еthodologiсal Мetbodsапd Priпсiplеsof Sуstеmiс Zoologу (Мaуr\,726 Мetrаrаbdotrls,96-9 8, 98f Меyеr,StеphеnС., з77 Miсhеl, Hеlеn,411 Miсhеnеr,СharlеsD., 732-7з3 Мiсrobеs.SeeЕvolutionaryЬiology Miсroеvolution(randomdrift), 225-227,475, 482, 666-668,842 Мiсrorаptor, 521 Мiеsсhеr,Friеdriсh'49 Mikluсho.Мaсlay,Nikolai, 622 Мill, Jоhn Stuart,545 Мillеr, StanlеyL., 55-58, 55f' 7зз-735 Мillеr,.!Иilliаm,357 Мillikan, Ruth' 322, 323 Мimiсry, 444-445, 735-739' 856' 905 Мinniсh, Sсott'392 Мirасlеs,naturalthеolоgyand,757,799 МisсеllапеrlusD isсoursеsСoпсеrпiпg thе Dissolutklп апd Сhапgеsof thе World (Raу\,827

967

968

lndeх ..Мissingliпk,'' 420' .518 аnd, З74 Мississippi,аntiеvоlutiоrrism Mitсhеll, Tlromas,360 Мitсhison, Naomi Нa|danе,627 Мivart, St. Gеоrgе,351, 352_353,651, 711,905 Мodеrn rеPtilеs'739-742 Мodеrп Sciепtific Уiешs апd Сbristiап Doсtriпеs Сompаrеd (Gmеinеr),354 Мodеrn synthеsis. SeеЕuolнtioп:Тhе Мodеrп Sупthesis;Population gеnеtiсs;Syпthеtiсthеory Мodеs of Spсciаtioп(М.J. D. \Whitе),

526-527,746, 747f, 749-7 5О3 Меrrdеliаntlrеorуand, 748-75Q fiеlds,з01_З05 Morphоgеnеtiс Morphology, 39, 93 in l)аrwin's thеory of naturalsеlесtion,17' 18f' 19 Morris, FrаnсisOrpеn,357 Morris, Hеrrr.yM., 45, з'59,372_з7З' 428,841 Мorris,John, 373 Мorton, Dr. D. Holmеs'2ti8-289 Morwood' Nliсhaеl'6З4 Мother Nаturе (Нrdy),643 251 Моthеr'sЬrothеr'sphеnon-rеnon, Мr' Dапс,iп'sSl,ootеr(MасDonald),348 742-744 N{iillеr'Frltz, 62З МolесularЬiology,257, 261, 262, Мullеr, HеrmannJсlsеph'488, 524, 906-908 527_529,68З' 747f' 7 50,75|-753, Мoleculаr Biologу апd Еuolutioп (joar885 n a l ) ,5 8 4 N4iillеr,Johannеs,622-62з Мolесular clock,1.47_149'\49f' 150f' Мiillеrian mirniсry,738 2 5 7 , 2 6 2 ,6 6 7 , 9 0 8 in histoгyof lifе thеo. gеnеtiсs, Multiсеllularit1', Molесulardеvеlopmеntal r i е s '8 1 788-789 Мolесularеvolution,132_151;ir-rforma- Мultilеvеlsеlесtion,\29' 618-62.О Murаtа' T., 550 1З6-\З7; tional maсromolесuiеs, M u t a t i о n ,6 Q 2 , 7 О | ;с h а n с еa n d ' multipliсitуаnd ratе hеtеrogеnеity, 47547 6; Сharlеswoгthаrrd,481; |44*147,146f;phylogеniеs оf organ. Chеtvеrikovand, 483; Сrow anс]. of isms,1З7-139,138f phylogеn,v 488-49О;DoЬzhanskyand, 524; gеnеs,14.3-144,1,45f;as proof of Drosophilааnd, 528-529;еvolutionеvolution,|49-1 511'rесonstruсtion ary Ьiоlоgyof disеаsе,285-289,293 mеthods'|з9-t4з, |40t, |41fi ||nigеnеtiсdrift, 153' 569;gеnomеs, formity and divеrsityin, 132_7З6, 164_|711harmful,and sехualrеpro\з4f' \35f' Seеаlso Моlесular сloсk duсtion,57 |_572;Kimura and,6661 100_101' Мolесularphylogеnеtiсs' \ I u l l е rа n d ' 7 5 l _ 7 . 5 . ]slp е с i a t i о n . 791-792 799-201;Vriеs and, 896 Мonаd to Мап: Thе Сoпceptof Mutualism,in soсialbеhаvior,246-247 Progrеssiп ЕuolutioпаrуBiologу ..Mv Lifе as аn AmatеurOгnithologist'' (Rusе),744-775 Мonkеy flowеrs,121_|24,Izzf' 184 \L-aсk\,672 МyogloЬin, еvсllutionarуhistory of' Мonkеypoх virus,28 1..282 14з-I44,145f Мonkеy Pоzzle tree,302, з03f, 304 М''steriesof I-ifе'sОrigiп, The Мonoесy' 848 (Thахt
Nаtionаl SсiсnсеЕdrrс (NSЕS)'.]87 Nаtiсlnal Sсlсiallsm,34 626,822,886-887 Nаtrrrаl histсlrr,'7.54-7 Nаtцt,"tl Histоr1,tlf thе (Lamarсk), 672 Nаturаl Hisfulrу Rеuiе

6.s0

Nаttп,,tl Iпh сrit,lttсе\С NаtuIаlism, philosoph thought and, 321 Nаturаlist (F,.o. Witsс Nltr.rralistiсfаllaсу,86 N"tturаlist tпl tbе Riuеl (Bаtеs),445 Сiriг Nаtuгal sеlесtiсlrr: сlr;rnсе aлd' 47 5_47l 3.50;Darп,in's devеl ' 506_507; iл Тhе Dе, 22_23; еvсllшtionof 5l.5_.516lFishеr'sgе 601; gеnolllе еvoluti Оп thе origiп of Sp in Ьiоlogiсаl forms, s1.lесi:ltiоtl'l 8 7_ 19.5 Nаturаl Sеlесtirп апd (Shеppard),755-75 Nаhtаl Sеlссtiсlпапd . 1Тrivеrs),tl90 Nаttlral thеoltlg,v'3.51' 7 56-762, 827-82-8, Nаturаl Th еrllogу (Pa| ,+0-5, 50-5,799-800 Nаturе сlf Sеlcсtitlп, Tl

922

Nаturе's Dua: Hеаliпg Сtllturе (Cоoс1ш'in) N аtiirliсh е Sсll i1lfппgs (Наесkеl),622,'62-з N аturp h ilrlsrlph ic, З 32 l 8 2 8 _ 8 зl . S с с . l / s r Н Nаutilus,69О Nаzism. See Nationаl l Nе:rndегtals,7 63-7 65, Nеаridеrthа| N,larr,6.50 NеЬulаr lrypothеsis,8! Nееdham, Josеph,21 8 Nеi' Мasаttlshi' .584'i NсiglrЬоr-iсlining'molr stud,vаnd. l42 Nеi's gеnеtiс dist:rnсе, Nсzssсrla, 289 ' 29 | Nеlsorl. Gагеth. 4.50

Iпdех

;_527,746, 747f' 749-7 5О;' ndеlianthеoryand, 748-750 h o g е n е г fi сi е l d s3, 0 l - 3 0 5 hology,39,9З; in Darwin'sthеory taturalsеlесtion, 17, 18f, 1'9 s, Franсisorpеn, 357 s ' H е n r yM . ' 4 5 , З 5 9 , 3 7 2 - З 7 З , i,941 s, John,373 ln, Dr. D. Нolmеs, 288-289 ,ood,Miсhaеl,634 эr Nаturе (Hrdy), 643 эr'sЬrothеr'sphеnomеnon,251 lаrшiп'sShсlotеr(МaсDonald),348 r, Fritz, 62З r, HеrmannJosеph,488, 524, '-529, 683,747f,7 50,7 51-753, r, Jоhannes,622-62З rian mimiсry,738 :еllularity,in historyof lifе thео,81 еvеlsеlесtion, \29, 61'8_620 : а ,Т . , 5 5 0 ton,602, 701;сhanсеand, 47Q Сhar|еsworthand' 481; tvеrikovand,483;Сrow and, -490; DoЬzhanskyand, 524; Бophilа and, 528-529;еvolutiоnЬiоIogo y f d i s е а s е2. 8 5 _ 2 8 9 . 2 9 3 зtiсdrift, 15З, 569;gеnolllеs' *171;harmful'and sеxualrеprоrion,577-572;Kimura and,666; I l е rа n d .75 |- 7 53 : s р е с i а t i о n . _201;Vriеs and, 896 tlism,in soсialЬеhavior,246_247 -ifеas an AmatеurOrnithologist'' :k1,672 'obin' еvolutionaryhistory of, -144,145f ries of Lifе's Оrigiп, Thе rxton, Bradlеy,and olsеn), -377,379 riforms,582 361 , Shahabuddin, , Сarl,730 groupsеlесtion, 619 еon,sЕgyptianехpеdition,500, f, 606 Суrt|,729 r'iuеof Trаuеls oп thе Аmаzсlп Rio Negro, А (A. R. !Иallaсе),

Nаtional SсiеnсеЕduс:rtiоn Stаndards

(NsЕs)'387

N a t i о n a l S o с i а l i s m '3 4 l , . 5 l 5 , 5 4 6 , 5 9 9 , 6 2 . 6 ,8 2 2 , 8 8 6 - 8 8 7 NаtureIhistо11 . 754-755 Nаturаl Historу of thе Iпuеrtеbrаtеs (L.amarck1,672 Nаtиrаl Historу Rеuiеtu ( journal), 6.50 N аturаl l пЬеritапсе (Gаlton),'59lJ Nаturalism, philosophy of еvоlutionary thought and, 32 I Nаtt,trаlist(Е. o. Wilson), 92З Nаturаlistiс fallaсy, 864 Nаturаlist сlп tbе Riucr Amаzсlпs, Тhе (Batеs),445 Nаturаl sеlесtion:Сair.rand, 465_466; сhаnсе and,475-476; Darwin on, 3.50;Darwin's dеvеlсlpmеntof, 506-507; in Thе Dеsсепt сlf Маll, 2 2 - 2 З : с v о | u t i o nr l f o p i n i t l n t l n ' 515-516; Fishеr'sЕ]еnеtiсal tlrеory оf, 601; gеnomе еvolutiсlnand, 15З; in Оп thе Оrigiп of Spесlсs, 15_16; rolе in Ьio|ogiсаlfоrms, 299-3 1 l; rolе in spесiation, 187_|95 Nаturаl Sеlесtitlп апd Неrеditу ( S h е p p a r d )7' 5 5 * 75 6 ' 8 5 7 Nаtиrаl Sеlесtioп апd Soсiаl Thеorу (Trivеrs),890 Natural thеоlоgy, 3.'1, .]62-36з' 756-762' 827_828,9 l з-91 8 Nаturаl Thеologу (Pаlеy),3.'0, 362, 40.5,.505,799-800 Nаtиrе of Sеlесtirlп'Tbе (SoЬеr),762, 922 Nаtиrе's Dttе: Hеаliпg Оur Frаgmепtеd Сulturе(Goodwin),З11 N аtйrliс h е S сh оpfuпgsgеsсh iсh t a (Hаесkеl), 622, 62з, 624 Nаturphilсlsсl1lhiе,3З2_ЗЗЗ, 44 |, 7 зo, 828_83l. Sее аIsсlНornology Nаutilus, 69О Nazism. Seс Nirtioгrill Soсialism Nеandеrtаls, 7 63-7 65' 7 6 5 f Nеandсrthal Мan, 650' 710 NеЬulаr h1,pсlthеsis, 89З Nееdhаm, Josеph, 218 Nеi' Мasatoshi, .'84, 765-766 NеighЬor-jоining,mоlесulaг еvolutiоn study and, 142 Nеi's gеnеtiс distаnсе' 766 Nеissеriа,289 ' 29 | Nеlson, Gаrеth, 4.50

Nеlson' Pau|, З77 Nеmеsis hypсlthеsis,855 Nеoсrеationism, 375_385. Sее аlso Intеlligеnt Dеsign (ID) Thеory; Sсiеntifiс сrеationism Nеo.Dаrwinism. See Synthеtiс thеory Nеo-Lamаrсkism, 334 Nеolithiс Тrапsitiсlп апd thе Gеnеtiсs of Populаtiotls iп Еuropе (CavalliSforzal,473 Nеrlpiliпа,691 Nеotеny' 773 Nеotropiсal Ьuttеrfliеs,186 Nеssе, Randolph, 923 Nеstеdnеss, еvolutionary progrеss and,

55.r-556

Nеuerе Prсlblеmе dеr Аbstаmmuпgslеhrе (RensсЬ|,832 Nеumann' Joaсhim, 763 Nеuroеthology' 543 Nеutral thсоry оf еvolution' 477-478, 489, 607_6О8' 666' 7 66-7 67' 908 Nеwеil, Norman, 6.l 1 Nеw-hеad hypothеsis' 7 88, 79 | Nеwman, John Hеnry, 919 Nеw systеmatiсs(Ьiosystеmatiсs), 41 6 Neш Sуstеmаtiсs, Tbе (J. S. Huхlеy), 646 Nеwton, Isаaс, 506 Niеtzsсhе, Friеdriсh, 364 Nonсоding DNA' 165-167 Nordеnskiбld , Еr1k, 622 Novaсеk, М. J., 101 Nuсlеatеd сеlls, dеvеlopmеnt of, .536-.139 Nuсlеiс ilсids: disсovеrу of, 49;'in history of lifе thеoriеs' 83. Seс с/st-l DNA; RNA Nusslеin-Volhаrd' Сhristianе, 529 Oсеan hydrothеrmal vеnts thеory of origin of lifе, 58-59, 62,68_69, 576 О dontorпiсbеs (Мarsh), 715 Оf Pаndаs апd Pеoplе (Davis and Kеnyon)' з77' З9z of thе Plurаlitу of Worlds (Whеwеll), 915 oglе, \William,427 ohtа' Tоmoko, 57 3, 7 01',7 67 -7 68 Okеn, Lorеnz,442,828 olduvai Gorgе' Tanzania, 677-67 8 Оп Аggrеssioп (Lorenz), 69З ..On Bеing on thе Right Sizе'' ( Н a l d a n е ) '6 2 8

969

970

Iпdех ..On

Cеrtаin Asресts of thе Еvolutionаry Рroсеss fron.rtlrе Standpoint of \4odеrn Gеnеtiсs'' (Сhеtvеrikov),483 Оп Grotuth апd Form (D.W. Thompson), 768-770 oп Нumап Nаturе (Е. o. Wilson), 865, 866,924,92.5 Оп Pаrt h епсlgепes i s (ow en), 7 9 6 Оп Rеspirоtitлz(Aristotlе),426 Оп thе Аrсhеtуpе апd Нomologiеs of the Vеrtebrаtе Skеlеton (owеп), 79.5 Оп thе Gulеrаtioп of Апimаls (Aristotlе),423' 424 Оп thе Gепesis of Spеciеs (Mivart), .352 ..On thе Law Whiсh Нas Rеgulatеd tlrе Introduсtiсlrrоf Nеw Spесiеs'' (A. R. .Wallaсе), 904 ..On thе Origin of Gеnеra'' (Сopе), 486 Оп the Оrigiп of Spесies (С. Darlvin), 14-22, 2'l 1-212, 504, 506-507, 77О-77\; Bаtеs and' 445; Ьiogеographу, 447448; сеntеnnial of, 515-5 16; еugеniсs'544; ..еvolutiоIr.. а n d ' 2 9 l е v o l l r r i o n a г yp r o g r е s s , 550_5.51; forпr vеrsus fl'rnсtiоn,.589; Haесkеl tlnd, 62З; Jеnkin's rеviеrv of, 662*663; Меndеl and, 30; miсrсlеvo. lution and mасroеvolution, 1'26; rеcapitulation thеory, 442; summarizеd, \4-221 supеrorgаnism сonсерt' 874; !Иhеwеll's plrilosophy and, 9 "|6-9 |7 Оn thе Pаrts сli Aпimals (Aristotlе)' 42з' 424' 425-427 ..on thе Tеr.rdеnсyof Variеtiеs tо Dеpart lrrdеfinitеly from thе originаl Typе'' (A. R. Wallaсе), 905 ..On thе Zoo|ogtсa| Rеlations of Man with thе Lowеr Animals', (T. Н. Нuxlеy), 710 Ontogеnеtiс сriter ton, 21'2 Опtogепу апd Ph1'logепy(S. J. GоLrld)' 2|4' 612,770,771-77з .. Ontogеnv rесаpitulatеsphylogеnv,'' 26, 210, 828_829. Sее аlso Rесapitulation Oparin, Alеksаndr I., 50, 628, 773-775 Oparin-Haldаnе hypothеsis, 7 зз, 77 4 Opеration sсiеnсе,З83 ..Ordеr for frсе,.' з09_310, 61Зf orеopitbеcus, 269 Organismiс еvo]ution and radiation b е f о г еt h е ( ) а m h г i а n '7 7 5 - 7 8 6 ; СamЬrian еxplosion of divеrsity' 784,

786; еarlуPrес;rmbrian lifе,775, 778_77L), 782; lаtеrPrесambriаr-r lifе, 782-781 O r g е l 'L е s l i еЕ . , 6 5 , 7 з 4 , 7 8 6 - 7 8 8 O r i a n s ,G . , 2 4 0 Originalsin, antiеvolutionism аnd, 371 Оrigiп of Еиkctrlotiс Сel/s(Margulis), 712 origin оf llfе, 49_791сonсlusions аIid pеrsPесtivеs' 72_741Еigеn'smodеl, .532-5.]3; еnvirоnmеntfor' 5l-.54; in historyof lifе thеoriеs,81, 101;N4illеr and,73З-7З5; Oparin and,77З_775; orgеl and, 7 86_788 overviеw,776f; polymеrizationof monomеrsand' 6О-62;pyritеаnd' 62-6Зl rеpliсаtiсlrr.s Ьеginnings, 6З_67.'rеpliсation's transition to RNA/DNA world,6i-68; synthеtiсorganiссompoundsand. 54_59; tеllPеraturеissuеs,52_5j, 68_7О;timеsсalеfor' 50_51.Sееаlso ЕхoЬiology;l-astсommon anсеstor (LсA) Оrigiп of Lifе (Оparin),773 Origin of vеrtе[]r2rtеs, 788-792; vertе' Ьratеarсhеtуpe, 796, 797f origin sсiеnсе,383' 395n4 Оrigiпs of GепomeАrсhitесturе,Tha (Lynсh),701 Оrigiпs of Lifе аnd Еuolutioп of thе Biospherе( journal),574 O r l i n g L, . W . , 2 4 1 Oг6, Joan (John)'.52'.56 Orr, H. Allеn, .529,74.1 Orr, Jamеs'35.Ч 258t' 260f' 26з Оrrorin tugепеttsis, Orthogеnеsis, 25' 881_882 Orthologs,585 OsЬorn, Hеnry Fairfiе|d,793-794 Ospovat,Dov, .51-5-5l7 C)stеiсhthyеs, 5t]2_.s83 Ostеr,Gесlгgе,924 ostrom,Johп, .519 o v е r t o n 'W i ] | i a mR . , 4 2 8 owеn, Dеnis'6.54 owеn' Riсhard,4f2 ' 0 f ' 2 6 f , 2 1 2 ,6 1 6 , 795-798;on Aristotlе,422; d i n o s a u r s5,1 8 ,5 1 9 ;h o m o l o g ya n d , 6з6, 637, 9 l*5;Huхlеy and,649, 65()' 710,920-921 Oyamа' Susаn,.]20 PaсkеrС , .,247 Pаеdomсlrphosis, 496

Palеontology, 80_104; с, thеoriеs' 37, .39;in D: natural sеlесtion,17, divеrsifiсation througt fossil rесord quality, 9 of vеrtеЬrаtеs' 790_79 824-8271'sеquеnсing lifе, 81-84; spесiаtion 9З-98; Stаnlе.vаnd' 8' TеilЬаrd dе Сhardin a Pаleontolo91, (Owеn), 2( Pаlеy, !Иilliam, 25, 405, 758,799-800; rеligio 362_363; soсiеtyand, Pangaea,449 Pangеnеsis, 5О7' 896_89 Panpsyсhiс idеntisпr,8З. Papinaеu, David, З22, 3 Parallеl adaptаtion, l09 Parallеl еvoltrtion,486Parallеl spесiation,189, Рaralogs, 585 Pаrапth ropus, 25 8t' 26с Pаrasitеs. See Нost para Park, Thomas, 900 Рarr, Albеrt' 8'58 810 Parsimony аnal1-sis, Parthеnogеnеsis,493 Path аnalysis' 928 Pattеrn-oriеntеd dеfinitit 1.79,l80t Pattеrson,Bryan, 8.59 Pattеrson, J
Iпdeх

z86;еarlyPrесamЬтian |i{е,775, 778-779, 7 82; |atetPrесamЬriаnlifе, 782-784 g е l ,L е s l i еЕ . , 6 5 , 7 З 4 , 7 8 6 - 7 8 8 ians,G., 240 iginalsin,antiеvolutionism and' 371 igin of Еukаrуotiс СеIls (Маrgulis), 712 iginоf lifе,49_79;сonсlusions аnd )еrspесtivеs'72-7 4; Еigen'smodеl, i32-533;еnvironmеnt for, .51-54;in listoryof lifе thеoriеs, 81, 101;Мillеr Lrrd,733-735;Oparin and.77З-775; )rgеl and' 7 86-788; ovеrview,776f; lolymеrizationof monomеrsand, iО-6Z;pуriteand,62-6З; rеpliсation,s lеgirrnings, 6З-673rеpliсation'stransiion to RNA/DNA world, 67-68; ynthеtiсorganiссompoundsand, i4-59;tеmpеrаtuге issuеs'52-53, i8-70;timеsсalе for, 50-51.Sее аlsсl ixoЬiology;Last сommonanсеstor LсA) igin of Lifе (Оparin|,77З igin of vеrtеЬrarcs, 7 88_792;vеrtеlrаtеarсhеty;l е, 796, 797f gin sсiеnсе,38З, 395n4 igiпsof GепomеArсbitесturе,Thе Lynсh),701 rgiпsсlf Lifе апd Еuolиtiolt сl|-thе iiсlsphеre ( journаl)'574 ing,L. \(., 241 i, Joan (John),52, 56 .' H' Allеn, 529,743 ., [amеs,358 "orlf'tugе?xе?lsis' 258t, 260i' 26з 'hogеnеsis, 25, 881-882 hologs,585 lorn' Hеnry F:rirfiеld,793-794 l o v а t ,D o v , 5 1 5 _ 5 1 7 еiсhthyеs, 582-583 еr, Georgе,924 roпr,John,519 : r t o nW , i l l i a mR . , 4 2 8 еn,Dеnis,654 еn, Riсhard,4f' 20f' 26f' 212' 616, 95-798;on Aristotlе,4)); inosаurs,518' .519;homolоgyand' 36, 637, 915;Нuхlеy and,649, 650, r0,920-921 tma,Susаn,320 < e rС' . , 2 4 7 Jomorphosis, 496

Рalеontology,80-104; сontеmporаry thеoriеs'37, З9; in Darwin'sthеoryof naturalsеlесtion,|7' 18_19,18f; divеrsifiсatioп throughtirnе'84_93; fossilrесordquality,98-101;origin of vеrtеЬratеs,790_79 t; Raup and, 824-827: sеquеnсingof history of lifе' 81-84;spесiаtionthеoriеs, 9З_98; Stanlеyand,869_870; Tеilhаrddе Chardinarrd'881_883 I,аlеoпtologу(owеn)' 20f .William, Palеy, 25, 405, 475476, 505, 758,799_800;rеligionand' З50. З62-36З;soсiеtyand, 332 Pangaea,449 Pаngеnеsis'507, 896_897 Panpsyсhiсidеntism,832 Рapinaеu,David,322, З2"З Pаrallеladaptation,109 Parallеlеvolution,486487, 8з2 Parаllеlspесiatiоn,189, |9 1_192,191i Рaralogs,.58.5 Pаrаnthropиs' 2 5 8t,260f , 265, 271 Parasitеs.SeeHost parasitееvolution Park,Thomas,900 Раrr,Albеrt' 858 Parsimonyanalysis,8 10 Parthеnogеnеsis' 493 Pаth analysis,928 Pаttеrlr-oгiеntеd dеfinition оf spесiation, 179,1.80t Pattеrson, Bryаn,859 Pattеrson, John Thomаs,488, 489 Pеarson,Еgon,.580 Pеarson,Kаrl, 580, 598, 800-804, 910-912 Pеarson'P. N.' 96 Pеdroja,Lydia Franсеs,859 Pеnnsylvania, antiеvolutionism and' 391,392-393 Pеppеrеdmoth,652_655,653[ 665-666 Pеptiсulсеrs,4з9440 Pеptidеnuсlеiсaсid (PNA), 60,64-67 Реrfесtion, аdaptationсontrovеrsiеs and, 114-11.5 ..Pеriodiсity Ехtinсtions of irr thе GеologiсalPast''(Raupand Sеpkoski),825 Pеripatriсspесiation.SeeFoundеr-еffесt modеlof sресiation Pеriphеral.isolаtеs spесi:rtion. See Foundеr-еffесt modеl of spесiation Pеtеrs,Jamеs,724

Pеtеrs,S. Е., 100 Pеtrornyzontiforms, 5 82 Phеnеs, 930_931 Рhеnеtiсists,840 P h епеtics (YaЬlokov), 93 1 Phеnеtiс SpесiеsСonсеpt, 1[l0r Pbепomeпoп сlf Мап, ТЙс (Tеilhard dе Сhаrdin),881 Phеrrotypеs:Dаu,kins and, .512_513; gеllotypеsand сhangеs in, 2.08,2О9f, 215-2_19,217f Рhеnсltyрiс plastiсit1-,228-2-29' 804-806 Phеnvlkеtonuria (РKU), 286, 2,93 Philosrphie zookэgiquе (Lamarсk), 3 Philosсlрlhy,еvolutionary Ьiolоgy and, 37З-З29: Ьiology's сontributior-rto philоsophy, 32 |_327 ; philosophy's сontribution to biology, 314_327 Philosоphу of BiсllogicаI Sсiеnсе (Hu||), 839 Phibsсlphу oi thе lпduсtiuc Sсiепсеs (]iИhеwеll),916 Phylеtiс gradualisrn,94-98, 94f, 88З Phуllсltахis,Ьiologiсal forms arrd' 299-з07, з01l' з03f Phylogеnеtiсs,57 8_579, 806-810 PhylogеnеtiсSpесiеsСonсеpt, 179, 1 8 0 / ,1 8 1 / Phylogеny, еmЬryсlsаs еvidеnсеоt, 2|()_213. Sее ttlso ..Ontсlgеnyгесapitulatеs phylogеny''; Rесapitulatior.r Phylсlgеography, 4.50 Phуsiсаl sсiеnсе,plrilosophv оf еvolutionаry thought and, З2-4-З27 Physitllogiсalgеnеtiсs' 927_929 Phytophаgоus insесts,849, 850, 851f, 852 PiаIrсiаni,G. B.' .]52 Piltdоwn Мan,811-813 Pinе snakе, 741f Pius IX (pоpе),352 Pius ХII (pсlpе),З55 Plantingа, Alvin, З63 Plants' 483-486, 508-510. Sее аlso Flowеring plants; Sееd plаnts; Vаsсulаr plаnts Plastiсity.Seс Phеnоtypiс plаsгiсiti. Platе tесtсlniс thettrу, 449 P l a t n i с k ,N o r m а n , 4 5 0 Plаto, 1_2' 42з, 544' 874 Plat1,рus,688' 689/ Playfair, lohn, 644, 698 Plеiotгopy, 218

L)

972

Iпdех Plеisгoсеrrеехtillсtions, 814-816. See a/soМass еХtinсtiOns Рlеitrophv, 88.5 Plеsiorтorphy' 633 Podos, Jеffrеy, 1 89 PoisсlпiпgDemoсrасу (Pгiсе)'359 Poiitiсal tlrеory, soсial Ьеhаviоr аnd,

250-2-s 1 Pollaсk,.J'B.,549_5.50

Polyandrv, еvolutionаry psyсhology and, 559 Polygynv' soсiаl Ьеlrаvitlr and, 2З9-248 Polvmеrizatior.r,of prеЬiotiс mоnoтnеrs' 60-62 Polymorphism, 4З4*4з 5, 7 5 6 Pol,vphеnism,228 Pоlyploidization, 2004О1, 2О2f Polvploidl., 485,7 52, S7I Pсllytypiс spесiеs. Sеe Sуstеtltаtiсsапd the Оrigiп of Speаеs Ptlпgo, )(1 Poppеr, Kаrl, 325 Poрulаtion gеnеtiсs'з2, 42_4з, 225, 482; DoЬzhansky апd, 522_525, 6ОЗ_604; Еwеns and, 572-573; Fеlsеnstеinаnd' 578_579; Нaldane and, 628; Lец,оntin аnd, 682-686. Sее аlsсl Synthеtiс tlrеory Populаtioп StL|diеsiп Birds (I,aсk), 671 Porifеra, 6|6 Portег, Gеоrgе, .5З2 Postmating isolating bаrriеrs, 182, 1 8 3 - ]8 6 , 1 8 З r , l 8 5 / PrесаmЬrian pеriod. See Orgаnismiс еvolutiсlnand radiаtiоn Ьеforе thе СamЬriar-r Prеdation, in history оf lifе thеoriеs,81 Prеrnatingisolаring bzrгriеrs,182_183, 18 3 / Prеrzеl syndromс, 288-289 Pr6vost, Cоnstant, 698 Priсе, Gесll.gеМсСrеаd1', з59, 364-з65, 722,842,84зf Primatе soсiеtiеs.in hisгоry of lifе tЬеo. riеs, 84 Prinсi1llеsсlf Gеologу (Lyеll), 8, 1lf, - 5 0 5 ,6 4 4 , 6 9 7 , 6 9 8 , 6 9 9 , 7 9 9 , 816_820,817f' 894,90з Priпсiplсs сlf Kп
Prillr апd PostеrЙ'lr Апаlуtiсs (Aristotlе), 42З P г i s < l n е rd' si l е r n r n ; ,2 - l 6 Priuаtе Lit'е of thе Gапnеts (fi|m\, 647 Problеms tlf Rclаtit,,еCrtпtth \J' S. Нuxlеy),646,770 Proсеssеdpsеudogеnеs'162 Proсessеs of orgапiс Еuсiutillп ( S t е b Ь i n s )8, 7 2 Proсеss-оriеntеddеfinition оf spесi:ltion, 779,1.80t Prсlсhronism,з58, 362 Progеnеsis,773 Progrеss. Sсс ЕlrlIutionагy progrеss Prokaryotеs:Ьaсtеriа as, 4З7:еndosymЬiоtiс rlrigin Of еukаI},otеsi]nd, 5з4-54 |' 536f, 537f, 5з9|; in history o f I i f еt h е o r i е s , 5 1 ,8 1 , 8 3 ; M a r g u l i s arld, 7 |2-71'З ..Pгоpеr S p h е r еt l f C o v r r n m е n t ,T h е ' . ( S p е n с е r )8, 6 7 Propliopithесиs, 260 Prсltесtivе rrrimiсry, 444-44 5 Protеins:Fitсh-Margoliash mеthod аnd' .584-.58.5; in hisтory of lifе thесlriеs, 8З; prсltеinеvolutioп, 607-6О8. Sее a/-.oAmino aсids ProtеoЬaсtеria,43 9 Protoсtista.53 8-.540 Provinе' Williaпr B., 56|f, 929 rr()хlmatе сausеs' /l' / -t-rtlсеllгl:ll геstr.rllrг' /(,J

Psеudogеnеs,1 6 | Psyсlrolоgiсаlасiаptаtiorr,5.58 Рsyсhologу:сontrastеdto еthology' .542;sосiаl Ьеhaviсlrаnd, 2.51_252, з4З, з44. Sее аlso Еvolutionаry psyсhоlogy PurrсtuatеdеquiliЬriurn' з7, з7f, 4 I, 41f, 94-98, 94f, t26_129, 612; Сlrаrlсswortlr аnd' 480; Маynаrd Smith arrd, 723; Raup aлd,824_825; S i n r p s o na n d , 8 5 1 ; s о с i е t 1 , a n d , 3 З 4 - 3 3 5 ; S t а n l е ya n d , 8 6 9 - 8 7 0 Punnеtt' Rеginаld, .531' 856 Pyritе, ro1еin origin oi |ifе, 62_6З Quаlity Sсiеnсе Еduсаtion (QSЕ), 389-390 Quirntitativеgеnеtiс thесlry,67 5-67 6 Quantitativе trait loсi 1QTLs), 8З.]-8з4 Quаntum еvolutiоn' [l83 Quаrtеrlу Rеuieu', 698

n-rimiсry Quasi.Batеsiar-r Quаsi-spесiеs'532_533

Raсе, 684_685,82\-82z Rаdiation. Sсс Adаptivе organisпriс еvolution Ьеfoге thе СаmЬriаn Radirrtion siсknеss: atoпl tеsts and' .524;NIullеr Х-rays and, 886, 887 Rаdiriаriеn, Dle (Haесkt Rаinv, Robеrt, .3.57 Rаndom drift. See Мiсr< Rаssепkreis,8З2 Rat сoat сo|or,469, 470 Raup' Dаvid М.' 824-82 855, 870 Rаw п-tаtеriаrl, аdaрtatiог and, ||З-|14, |29 \ay,.lohn, 827-828 Rесаpitulation, 208-2 10 828-831' 829f.Baеr's 44|44З; Coulсl аnd, l аnо'

bl'J'

бl'J

Rесhеnbеrg,Ingo. 549 Rесiproсal altruism' 409Rесiproсitv, in soсiаl Ьеh Rесognitiorr Spесies Сonс RесomЬinationаIspесiаt

170-172, 200,737

Rеd Quееn hypothеsis,5, Rееfs' in history of lifе th Rеgrеssion to thе mеan, . ..Rеgulаtiсln,'' 216 Rеhnquist, \й/illiam,374, Rеillo, Paul, 197 Rеinf
Iпdех d PostеriсlrАпаlуtiсs (Aristotlе), 's dilеmma'246 ,'ifеof thе Gаппеts(fi|m|,647 s of RеlаtiuеGroшth (]. S. у ) '6 4 6 , 7 7 0 d psеudogеnеs, 162 s of orgапic Еuolиtiсlп ,ins),872 : l r i е n г еddе f i l t i t i oonf s p е с i a t i o n . 80, rism,3.58,362 ;is,773 . SeeЕvolutionaryрrogrеss ltеs:baсtеriaas,4З7;еndosymоriginof еukaryotеs аnd' 4 | ' 5 3 6 [ '5 з 7 [ '5 з 9 f :i n h i s г o r у t h е o r i е 5s '| . 8 l . 8 3 l M a r g u l i s ,12-71З Sphеrеof Govеrnmеnt,Thе'' :er\r867 'ithесиs,260 .е mimiсry,444445 Fitсh-Мargoliash mеthodаnd, 8 5 ;i n h i s г o r yo f l i f еt h е o r i е s , otеinеvolutioл,607_608.Sее mino aсids Lсtеria,439 ;ta,538-540 \)Иilliаm B . ,5 6 1 f , 9 2 9 te сattsеs,727 iI rеstrаlnt' /UJ

эnеs,1 61 ,giсalаdaptation,558 |gy:сontrastеd to еthology, oсia] bеhavior and, 25\*252, 44. Sее a/so Еvolutionаry psy.

iv г е dе q u i l i Ь r i u m3,7 , З 7 f, 4 1 , 4-98, 94f, 126-1,29,6121 )sworthand, 480; Мaynard а n d .7 2 3 l R a u pa n d .8 2 4 _ 8 2 5 ; o n a n d ' 8 6 1 ;s o с i е t ya n d , 35; Stanlеyand, 869-870 R е g i n а l d5, з 1 , 8 5 6 llе in originof |lfe,62-63 SсiеnсеЕduсation(QSЕ)' 90 Ltivеgеnеtiсthеory,675-676 ttivеtrait loсi (QТLs), 34 n еvolution,883 у Rеuiеш,698

mimiсry,738 Quasi-Bаtеsiаn 532-533 Quasi-spесiеs, Raсе,684-685,821_824,8З2'862 Radiаtion.SeeAdaptivеradiаtion; Organismiсеvolutionand radiation Ьеforеthе СamЬrian R а d i а t i o ns i с k n е s sа:г o m i сW е а p о n s tеstsand, 524;Мullеr and,752; Х - r a y sа n d ,8 8 6 ,8 8 7 Rаdirllаriеп, Dlс (Haесkеl),623 Rаiny' RoЬеrt'357 Rаndom drift. Sсe Miсroеvolution Rаssепkrеis,8З2 Rat сoаt сo1or,469, 47Оf Raup, David М.,824_827' 826f, 854, 8 5 5 ,8 7 0 R a w m a t е r i e la. d а p t а t i oсr o r ntrоvеrsiеs and,113-114,129 Ray, John, 827-828 208-210' 21|f, 2I4, Rесapitulation, 828-831' 829f; Baer,srеjесtionof, 441443 Gould and, 772;tlaeсkel aлd,62З,625 Ingo,.549 RесhеnЬеrg, Rесiproсalaltruism,409_410,890 R е с i p г о с i t yi n' s о с i а IЬ е h а v i o r2' 4 ь - 2 4 7 RесognitionSpесiеsСonсеpt'180r Rесombinationаl spесiаtion,162_1'6з, 170-172,200,731 Rеd Quееnhypоthеsis, 571'_572,641' Rееfs,in historyof life thеoriеs,81 Rеgrеssion to thе mеan,598 ..Rеgulation,'' 216 Rеhnquist'\William,З74' З84 Rеillo,Paul' 197 Rеinforсеmеnt,spесiationand, 1.94-195,'t98 Rеinhаrdt,D., з04_305 Reiпuепtiпgthе Sасrеd(Kаuffman),447 Rеlеvantsoiutionсonсеpt'600 R е l i g i o nЗ, 4 8 - 3 6 9 ;С . D a r w i na n d , 2 5 ' 3 4 8 _ 3 5 2з' 6 2 - 3 6 з ' . 5 0 5 _ 5 0 6 51 ' 3' 7 5 8 , 7 9 9 _ 8 О 0Е;. D a r w i na n d ' 5 1 0 ; Dawkins and,44, 728, 758, 800; DoЬzhansky and, 522, 525; еarly еvo. lutionarythoughtand,4-.5;еvolutionary progrеssand, 364-36.5;gеnеtiсsаnd, 32_33;Grаy аnd, 61B; Hutton and,644;Huхlеy and,.351, 3 5 2 ,6 5 1 'I s l a m ,3 6 1 - 3 6 2 ,3 6 3 1 ' 36.5;Lасk and' Judaism'2, 360_361', 67 |-672; Lyеll and' 1,9,6991Pa|eу and, 350, З62_З6З;Protеstantism,

356-359,365; rесurringthеmеs, З 62_З65; Roman Cаtholiсism, 3 5 2 - 3 . 5 63' 6 2 , з 6 З , З 6 4 ,З 6 6 , 7 5 7 ; Tеilhаrddе Сhаrdin аnd, 881-883; !Иallaсеand' 513, 514;Whеwеlland, .!Иilson 913_918; and,925.Sееаlsсl A n t i е v ou|t i o n i s mС; h r i s t i a n i t y ; Natural thеоlogy;Sсiеntifiссrеation. lsm

Rеnsсh' Bеrnhard,831-833' 877 Rеpliсa-plating ехpеrimеnt, 679 Rеpliсation,839; Ьеginningsof, 6З-67; in historyof Iifеthеoтiеs'82; transitior.rto RNA/DNA, 67-68 Rеpliсatorеquation'З37_338 Rеprоduсtion'See Еvolution of lifе historiеs;Sееdрlаnts;Sеxualrеproduс. Soсia]Ьеhavior tion;Sехualsеlесtion; isolatiоn,\94-195' 197 Rерroduсtivе Rеprodr.rсtivе skеw, 24.5 Rеptilеs.SeeМodеrn rеptilеs Rеpubliс(Platо),544 R е s n i с kD , a v i d ,1 1 1 polygyny,242 Rеsourсе.dеfеnsе Rеvеalеdthеology,756-757, 758 Rhizсlsolепiа, 96,97f Riсhards,RoЬеrtJ., 511-512' 551 Riсhardson,Miсhaеl,626 Riсklеfs'RoЬеrt,451 RiеsеЬеrg, Lorеn,200 Right-handеdnеss, 564 Rilеy,!ИilliamBеll' 359 Rimmеr,Наrry, 359 ..Risе,Fall, and Rеsurrесtion of Group Sеlесtion, Thе', (Borrеllo),62О R N A : е v o l u t i o no f, 6 7 - 6 8 , 7 1 ; i n h i s t o ry of lifе thеoriеs'82-83; hydrothеrmal vеntsthеoryand, 58,68_69; Мillеr-Urеyехpеrimеntand, 56; prесursorsof,6З-67. Sеeаlso Gеnomе еvolution;Molесularеvolution R N A w o r l d ,6 4 , 6 7 - 6 8 , 7 I , 7 4 , 5 7 7 ; Еigеnand, 533;Мillеr aпd,7З4-7З51 Orgеl and, 786_787 RoЬеrtson,Alan, .578,833-834 RoЬеrtson'ForЬеsW., 529 Robiп Rеdbrеаst(Lack\, 669 RoЬots,549-550 Roсkеfеllеr, John D., 862 R о d е ,B . М . , 6 2 Roе, Anna Мiriam, 859 Roman Сathoiiсism'з52*з56,з62' з 6 з , з 6 4 , 3 6 6 ' 75 7 R o m a s h o vD, . D . , 4 8 3

L)7.1

974

Iпdех Romеr' Alfrеd Shеrwood,834-836,859 Romеr,Ruth HiЬЬard,835 Rosеllаs'gеographiсal variationiл, 417f Rosеnbеrg,Alех' З26 Rosеvillе,CA, antiеvolutionism and, 388-390 Ross,Hugh, 377 Rothsсhild,Wa|ter,724 Rouх' !7ilhеlm,622, 625 Rudwiсk,Мartin' 501 Rundlе'Howard, 195 Rusе,Miсhaе|,45, З21',348, 428,462f, 5 5r, 744-775, 925 Russеll'Еdward S., 588-590 Russia' sосiеty'srесеptionof еvolution, 336-337 Ri-itimеyеr,Ludwig, 625 S а с с h е rlil,i k , 6 5 4 Sagаn'Сarl, 59 Sagan,Dorian, 713 Sаhеlаnthropus,2 5 8t, 260f , 262-263, 696 Saitоu,N., 766 Salamandеrs,414 Saitationism, 25, 5О7,802 Sаlt-induсеdpеptidеformationrеaсtion (SIPF),62 Samplingеffесts,quality of fossil rесord and,99-100 S a r i с h v, . \ 4 . , 2 5 7 S A R S ,2 8 2 ,2 8 4 SatеllitеDNA, 158_159.Seea/sоDNA Savagе,Jay М., 90I_902 S a х ,K a r l , 4 1 6 , 8 7 1 Sсаlапаturа(сhainof Ьеing),209, 5.50 Sсaliа,Antсlnin,З74, 384 Sсhеlling'Friеdriсh'332, 440, 828 Sсhеmskе,Dolg, 123-1,24 Sсhlеiсhеr,August' 625 Sсhlutеr,Dolph, 195 Sсhmalhausеn'Ivan IvаnovicЬ, 21'6, 8з7-8з9 Sсhmidt-Niеlsеn' Knut, 443444 Sсhopf,ThomasJ. М',824 Sсhrodingеr, Еrwin, 886 SсhwalЬе,Gustav,763, 764 Sсhtuапzfrаgе, 626 Sсiепсeаs а Procеss(Hull),839-841 Sсiеnсеfor thе Pеорlе,866 Sсiеnсеof human bеttеrmеnt,862. Sее aiso Еugеniсs Sсienсeof Lifе, Тhе (H. G. Y/еlls,J. S. Нuхlеy, and G. P. !Иеlls),646

S с i е n t i hссг е а t i o n i s mЗ .6 4 .3 7 2 - з 75 , 395n1,428_429,84|_844,843f.Sее a/soAntiеvolutionism;Сrеationism; Sсopеstrial Sсiеntifiсmatеrialism,43_44 SсiеntificМеmoirs (T. H. Huхlеy), 651 Sсiеntifiсmеthod:Ayala and,435; Intеlligеnt Dеsignand,З79_З84,393 s г u d yo f d i n o s а u ras n d ,5 l 7 . 5 2 | _ 5 2 2 ..Sсiеntist,', first usе of tеrm, 913 Sсopеs,Thomаs John,З7I,844-845 Sсopеstrial,з 59,371',844-847 Sсott,Е. с., 385 Sсott' William Bеrrуman,79З Sеaliliеs'691 Sеarlе,Gеorgе,354 Sеdgwiсk,Adam, 357, 505' 894 Sееdplants, 847-852 Sеgrеgation, Меndеl and,7З0-7 З1',7ЗОf Sеlесtionoflsеlесtionfor, 762 SеlfishGепе, TЙe (Dawkins\,5I2, 727, 853-854,874 Sеlf-organization, in soсiаl Ьеhavior, 249-2s0,308-309 Sеlf-Оrgапizаtioпiп Bkiogiсаl Sуstеms ( С а m a z i n е 3) ,0 9 Sеlf-sасrifiсialЬеhavior.SeeAltruism SеImапu. Сrlbb Сouпtrу Sсhсlol Distriсt, 391 Sеmon,Riсhard'3З4, 622 Sеnеsсеnсе, 569, 721, 922-92з Sеpkoski,J. John ..Jaсk,''Jr.,З7, 91, 9 2 , 9 9 , 4 5 1 ,8 2 5 , 8 5 4 - 8 5 6 SеrеЬrovsky' A. s., 885 Sеthе'Anna, 623 Sеvеrеaсutеrеspiratorysyndromе (SARS),282,284 Sеvеrtzov, Alехеj,837 Seшаll Wrightапd ЕuolиtioпаrуBiologу (Provinе), 929 Sех, еvolutionof. Sсe Еvolution of sеx Sехапd Deаth (Stere|пyand Griffiths)' -)L/

Sехапd Еuolиtioп(G. С. Williаms),922 Sехualсоnfliсt' spесiationand, 198 Sеxuаlrеproduсtion:Fеlsеnstеinand, 579;Нamiltonand,630_631;in his. tory оf lifе thеoriеs,81, 83; spееdof еvolutionaпd,,7 84i \Williamsand,922 Sехualsеlесtion'507, 514,89О;in Thе Dеsсепtof Мап' 22_23;Hamilton and, Оrigiп of Speсiеs,16_17,16f, spесiatioп, \96_199

Shapiro, Josеph, 701 Shaw, Gеorgе Bеrnаr Shаw' Kеrry' 199 Shеldon, P. R., 95, 9; Shеppard' Philip М', 588,755-756,856 ..Shifting Ьаlanсе'' th \Аo_sА) Аo4_Аo\

928 Shoсk, Еvеrеtt,58 Shoеmakеr, Gеnе anс Siсklе-сеllanеmia,45 Sigпаls for Suruiuаl (I SimЬеrloff, Daniеl, 6i Simon, Мargarеtе (G Simpson, Gеorgе Gayl 314,.5517 , 25,858 Singеr, Pеtеr' 864 Siuаpithесus, 261 Skеlеtons,in history t Skin сolor, gеograph human, 268. Sее аl Skull, owеn's thеory Slatkin, Мontgomеrу Smith, A. 8., 99 Smith, William RoЬе Snails, 203 S n а k е s , 7 4 7 , 7 4 7 fS. е tilеs Snеath' Pеtеr,633 Snow, Dr. John,290 SoЬеr, Еlliott' 316, з 922 Soсial Ьеhavior' 125, porafy thеoliеs' 37 mесhanisms'249_2 thеory of natural st 1 8 f h u m a n s o с i a ll 2"50-252l,natural h 237-239; non-kins 246_247; soсial va] tivе strаtеgiеs'247. orу,241-245' tЬеo works,239-241.Sr Soсial Dаrwinism' 29 863f Soсiаl Еuolutioп (Тril Soсiаl Stаtistiсs(Sреn Soсiеty, 84,3з0_з47, thеory's ехplanatio еvolution's rесеptio shaping of еvolutio ЗЗ2-зз6. Sеe аlso l Soсiа1Ьеhаvior

lпdех 364, 372_З75, с сrеаtionism' 1, 428429, 841-844, 843f. Sеe Crеationrsm; \ntiеvоlutionism; :s triаl iс rnatеrialism,4з44 ic Меmoirs(T. Н. Huxlеy)' 651 iс mеthod:Ayala аnd,435; igеntDеsign and,379_384, 3931' .of dinosaursand,517, 521-522 ist,',firstusеof tеrm,913 ThоmаsJohn' 371, 844-845 trial,359, 37I, 844-847 1 .С . ' 3 8 5 Villiam Bеrryman,793 '-s,691 Gеorgе'354 с k . A d а m .3 5 7 ' 5 0 5 ' 8 9 4 .ants,847-852 ttion,Меndеl and,730-73|, 73Оf эn of/sеlесtionfot, 762 Gеnе,Thе (Dawkins)'512,727, -854,874 i n' s o с i а lb е h a v i o r . ganizатion -2.r0,308-309 rgапizаtioпiп Bioklgiсаl Sуstems nazinе)'309 Sсс Altruisrn сrifiсiаlbеЬar'ioг. t u. Сobb СouпtrуSсbool rict,391 . ,R i с h a r d З , З4,622 е n с е , 5 6 97' 2 1 , 9 2 2 _ 9 2 3 ...|асk,'' jr., З7, 97, ski,J. John 99,45L,82-5,854-856 ovsky,A. S., 88,t Anna,623 aсutеrеspiratorуsyndromе RS),282,284 zov,Alехеj,837 , Wrightапd ЕurllutionаrуBiolt',lgу 'vinе|,929 rоlutionof. SeeЕvolution of sех d Dеаth (Stеrеlnyand Griffiths), tlЕuolutioп(G. С. williams),922 сonfliсt,spесiationand, 198 rеproduсtion:Fеisеnstеinаnd, ;Нamiltonand' 630-631;in hisof lifе thеoriеs,81, 83; sрееdof u t i о na n d '7 8 4 l W i l l i a m sa n d . 9 2 2 5О7,5!4,89О in Thе sеlесtiоn, :епtof Маn,22-23; Нamilton 631;Irishе|k,42f;in Оп thе ,,inof Speсies,\6-1,7,76f; spесia, 196-\99

Slrapiro'Jоsеph,701 Slralv,GеоrgеBеrnard,34l Slraw,Kеrry, 199 Shеldon,P. R'' 95, 97 Shеppard,Philip N1.' 32' 465-466' 48|, 5 8 8 , 7 5 5 - 7 5 6 ,8 5 6 - 8 5 8 ..ShiftingЬalаnсе''thеory,477, 52з, 560-562,604-605,884, 892,900, 928 Shосk,Еvеrеtt,58 Gеnеаnd Сaгolуn,411 Sl-roеmakеr' аnеmia'450 Siсklе-сеll SigпаIsfor SuruiuаI(film)'889 SimЬеrlоff,Daniеl,67I, 824_825,924 (Gretе|),724 Simon,-N{argarеtе Simpsсln.GеorgеGаylord,32, 33, 35' 882-884,892 3 14,551,725,8-58-861, Singеr,Pеtеr,864 Siuаpitbесиs,26I Skеlеtons,in Ьistoryof lifе thеoriеs'81 Skin сolor,gеographiсdistriЬutionof hrrman.268. Sеea/soRaсе Skull,Owеn'sthеorуof,796 Slatkin,Мontgomеry,479, 900 S m i t h A, . 8 . , 9 9 Smith,N(illiaпrRoЬеrtson,365 Snails,203 Snаkеs,741l,741'f'SеeаIsоModеrn rеptilеs Snеаth,Pеtеr,633 Snow,Dr. lоhn, 290 S o Ь е rЕ , l l i o t t ,3 1 6 ,з I 7 , 4 Q 8 - 4 0 9 , 7 6 2 , 922 S t l с i a l l l е h а v i o r ,| 2 5 , 2 3 7 - 2 5 5 l с o l l t е m . porary thеoriеs,37; сoordinating mесhanisms, 249-2501' in Darwin's thеоry of natural sеlесtion' 17' |8' 18f human sосial biologv and, 2 5 0_2 521'natural historv foundаtions, 2З7 -239 : non-kinship rеlationships, 246-2-47;sосial variants and аltеrnativе stтatеgiеs,247 -248; synthеtiсthеorу, 24 1-24 5; thеorеtiсal framе. works, 239-241. Sее a/so Soсiеty Soсial Darwinisnr' 29, 515' 862-865'

86зf

Soсiаl Еuсlltttioz (Trivеrs), 890 Sсlсiаl Stаtistiсs (Spеnсеr), 867 Soсiеtу, 84, з3О-з47, 365; еvolutionarу thеory's еxplаnations o|, 337_343 еvolution'srесеption Ьу, 3З6_3З7; shaping of еvolutionаry thеorv by, 3 З2_з з 6. Sее аlso Antiеvolutionism; Soсiаl bеhavior

SoсiоЬiolоgy'25a-252, 342-з4з' 8, 642-643,864 -557--55 Soсiobiolоgу:Tbе Nеul Sупtbеsis\F,.o. Wilson),з7, З42-34з, 865-866,924 S o k a l ,R o b е r t ,6 З з , 7 3 2 modеls.SeeЕxobiologv Solar-еvolr'rtiоn 5o16,R. V., 307-308,309 Solidаrism,864 SоlnhоfеnLimеstonеdеposits,420' 518 Sorеnson,Мiсhаеl' 194 Souvay,Сharlеs,354 Spaсе.SeeЕxoЬiology Spadеfoottoads,41'7f ..Spaltungsgеsеtz dеr Bаstardе,Das,, (Vriеs)'895 S p а n d r е l s4,1 , 4 | f ..Spаndrеls of Sаn Мarсo and thе Тhе'' (S..J. Paradigпr, Рanglossian Gould аnd Lеwсlntin),612' 683 9 з-98, 177-207,88З;adapSpесiation, tationand, 107;Саrson and,467: tсl sttrdyof, 177-\79, сhallеngеs 178f.dеfinitionsof, 179-182,180t' у n , 6 0 З - 6 0 6 ;g е 1 8 1 f iD o Ь z h a n s k o rolе in' 2О1-203;isolating drift's nеtiс Ьarriеra s n d ' l 8 2 - 1 8 6 , 1 8 3 r ,1 8 5 f . Maynard Smith and, 724-7273mttation's rolе tn,799_201.;natural sеlесtion,srolе in, 1'87_195'plantsand Сlаusеn,48З-486:sехualsеlесtion's r o l еi n , 1 9 6 - | 9 9 -s y m р a t r i с4.1 8 . S е е llsо МоJes of Sрссiаtitlп Spесirtioпgеrrеs,186 сurvе,451 Spесiеs-аrеa 686 Spесiеs P lапtаrum(L,innaеus), Spесiеssеlесtion,95' 612-6|'з Spеnсеr,Неrbеrt'27-28,29, 340, 544, .551,562, 862, 86з, 866-869,874 Sol, .532 Spiеgеlman, S р i r i t u a l i s mW, a l l а с еa n d ,5 l 3 , 5 | 4 . S e е a/srlRеligioп 157, 158 Sрliсеosomе, Spratt,Brian,72З Spurway,Hеlеn,628 741 Squamatеs, S t a b i l i z i nsgе l е с t i o n8.3 7 , 8 3 8 - 8 3 9 '9 1 1 Stаgеsiп tbе Еt,olutiсlпсlf PIaпt Spесiеs ( С l а u s е n )4,8 5 S t a n d е rP' . F , . , z 4 7 Stanlеy,StеvеnМ., 6\2' 869-870 Stаpbуl oсoссlts аureus, 289-29 0 Stasis:miсroеvolutiorrand maсroеvоlu. 94_98. spесiation, tion,126_1'29; 17Bf

975

976

l ltсlех Statistiсalаppraisalof еvolutionaгy t r е е s ,l 4 3 StаtistiсаlМеthods for llеsеаrсh Workers(R. A. Fishеr),580 Stаtistiсаl Таbl еs l'r',rB io l o3i саl, Аgriсulturаl,апd Меdiсаl Rеsеаrсh (R. A. }.ishеrand Yаtеs),580-.581 StеЬЬins,GеоrgеLеdyаrd'з.2,.]l4, 4 \ 6 ' 4 8 5 ' 55 | ' 7 2 2 , 8 7| - 8 7 з ' 8 9 2 _ 89 з Stеrеlny,Kim' 327 StеrilеhvЬrids,184-185' 18.'f,,605 Stеrn,Curt, 7? l Nеttiе N{.'748 Stеr,еns, Stеwаrt,Bаlftlrrr,363 StiсklеЬaсks,191-192, 195 Stoсhastiссlосk,rтolесularеvolutionirs, 147-148 Sttlllе Аgе Сulturсs ll| Кепуа (',оloпу,

Thе (L. S. B. Lсаkеi.),677 Stсlrrs,G. W., 99 Еduard, 622 StrasЬttгgеr, Strесkеr,Adсllplr.49, 54,56, .57f,58 StrеsеmаnЕ n r' r r ' i n7, 2 4 , 8 з 2 , 8 7 7 Stгomatolitеs ' 775, 777f, 778f, 779, 77ef, 780f, 78lf, 782 .Гhеorу, Тhе Struсturесlf ЕL,olutioпаrу ( S .J . G o u l d ) з. 2 7 , 6 1 4 Strпсturесlf SсiсtttifiсRеuсllutiоtts ( K u h n ) ,- i 2 - 5 Stttdуof lпstiпсt,ТДe (Tir-rЬетgеn), 889 sttlrtеvаnt'Alfrсd, 18,1_1 8.5,.52з' s 2 7 - s 2 8 ,s z e , 7 4 7 f , 7 . 5 07, - 5r Sullrеz,Frаnсisсo,3.51 Grаham,862 Sumnсr,\)Иilliаrn 8 7' З _ 8 75 , 9 2 5 Supеrorgаnism ..Srrrfaсеs Vаluе Rеvisitеd'' of Sеlесtivе (S. Vright), 929 .'Sirrvival of thе fittеst'''j40, 544' 863, 867

Swап-rping еffесt,731 pеas,59[i Sш,ееt Stifts iп сl Т)u,c| (l-асk),669 SуmЬiоgеrrеsi s, 536-53tt rеlatiоr-rslrip, philosophy SymЬol-targеt of еvoltrtionary tlrоr.rght and, з22_з24 S \ ' m p а t r isсp е с i i r t i o r1l7' 8 ' l 8 7 , l 8 8 F . 1 9 1 , 1 9 2 - 1 1 ) 41 ,9 3 / ,1 9 8 ,4 1 t l ;B u s h 463; Маynаrd Srтithаnd, 723; ar-rd, \)Иhitе аnd, 74З 142-l43' 26 |, 63З, Sr,rrарornorphiеs' ь ] S . S с . , a / 5 .l ), l r 1 ' l o g с n с t i с s

Synapsids, 740 Sуr.rthеtiс thеоry,30-35, 448, 547, . 5 9 4D ; o Ь z h а n s k yа n d , 6 0 3 _ 6 0 6 ' 8 6 1 ; l . . i s h еаrn с l '6 0 2 , 6 2 7 _ 6 2 8 ; G o l d s с Ь n l i dаt r r d ,6 l 0 ; Н u x l е y а п d . 5 4 7 - 5 4 9 6' 4 5 _ 6 4 9 , 8 6 1M; а y r a n d , 7 2 5 , 8 6 1 , 8 76 - 8 7 8 p h i l o s o p h yo f е v o l u t i о n а rt!l.r o u g h at n d , 3 1 4 - 3 19 ; R е n s с hа n с l '8 3 1 _ 8 3 2 ;S l r е р р a r d аnd, 7.5.5; and, sсlсialЬеlrаr,ior 2 4 | _ 2 4 5 , 2 4 7 ,З З 4 1S t е b Ь i n a s nd' 892_89з.Sееalso Еuсllutitlп:Thе М сld еrп Sl'l tth е sis; Pоpirlationgе11еt1сs SJ,stеmаNсltttrае (l-innаеus),686, 875-876 S y s t е m a t i с s|, 9 , з 9 , 7 2 5 _ 7 2 6 ' 7 6 6 . S е е a/sсl Plryl
Viеtt,,tlf thе Primаrу Diuisillпs r-,fthе Апiпшl Kiпgdсlm (R. Е. Grant), 617 Tаir' P. (i.. .]6З Таphonorтrr.'879_881 Tatli, Adеm, 361 Tatum, Еdwаrd, 678 Tаung Сhild, 694, 696 T:rutаrаs'741 Tахol, 8.50 Тахon сyсlе, 4.5l

Tееtl-r, human еvolutionstuсlyand, 2 5 8 t '2 6 2 _ 2 6 62' 7 1 _ 2 7 2 4 , з9 Tеilhаrddе СIrardin,Piеrrе,.3.3, 35.5. з 6 4 , 4 4 6 ' 8 8 ] - 8 8 3 ;P i l t d с l w n Man rrnd,812-813 . ' T е | еl lI t l g i с a l Е х p I e n а t i t l l l isn Еvоlutiсlnarv Biology'' (Al'ala)' 4З4 Tеlеology, 362-З63' 364 Tеlеosts, 5 8.3 Tеl
Tеmplеton,t|an, 179, Tеmpoапd Мodе in Е (Simpsоn), 860' 883 Tеnnеssее, antiеvoluti SееаIso Sсopеstrial Tеnnyson,Alfrеd, Lor 894-895 Tеrrеstrialization'in h r i е s ,8 1 - 8 2 Tеstudinеs,740 Tеtrapods:digit pattеr divеrsifiсation,88-8 Thахton,Сharlеs,376 Thеistiсsсiеnсе,383 Thеophrаstus,422 ..Thеoryоf Populatiо 867 Thеorу of thе Еаrth (Е Tbеorу of thе Еаrth (| ..ТhisViеw of l-ifе'' (S Тhompson,D'Arсy !И 6Iзf'759,768_77 35 Тhomsоn,.!7illiam' Thоrpе,w. H.' 672 Тhrеosеnuсlеiсасid (l Tibayrеnс,Мiсhеl,43 Tiеdеmаnn,Friеdriсh T i m Ь е r l a k еP,, H . ' 7 3 ' Timofее{{-RеssovskJ Vladimiroviсh'483' TinЬеrgеn,Niko,2375 9 2 , 6 9 2 , 6 9 38,8 8 Tit'.lnotЬerе,794f Tit-for-tat(TAТ),in sс 246 Tools, human еvolutio Torrеy,John,617 Tоwnsеnd,LuthеrTra 506 Тrаnsformism, thеo Transmutаtior-ral Tгansposablееlеmеnt gеnomеs'159-1'60 Trее of lifе mеtaphor 458f Darwin and, 1 Наесkеl and'28f; Ll molесularеvolution Seеаlso Phylоgеnе Trееsand forеsts'in hi riеs,82 Т. Rех апd tbе Сrаtеr t|varеz),412 ТriloЬitееуe,7 59,76С Тrivеrs' Robеrt,240' j 889-891

Ittdex

30-35, 448,547, kv and, 503-606, 1 ,6 0 2 , 6 2 7 - 6 2 8 ; r d , 6 1 0 1H u x l e y a n d , 649, 861,;Mayr and, .8711;philosophy olought and, 3 l4-3I 9; i1-832; Sl.reppard I behavior ar.rd, 3 , 1 4 ;S t e b b i n sa n d . lso Euctlution: Thc e s l - sP; o p u l a t i o n g e ( l - i n n a e u s )6, 8 6 , 9 , 7 2 5 - 7 2 6 , 7 6 6 .S c c lcs iiogeography: Vicariance(G. Nelson

t50 be Origin of Species 11, 725, 726f, q1,( journal), 8 10 :ic Philosophy, A n C " ( S .W r i g h t ) , 9 2 8

rJ2-84, 338 :he PrintttryI) it,isittns Kingdom(R. E. Grant),

-881 578 ,696

rlution study and, )il-)7) 419 Jin, Pierre,3-1,3-5.5, 883; Piltdown Man ,larrationsin L o l o g y "( A y a l a ) , 4 3 4 53,364 l 5 - 5 ,l 5 t i :, 356 , The (E. Darrn,in),

Templeton,Llan, 1,79,203 Tempoand Mode in Euolution ( S i m p s o n8) ,6 0 ,8 8 3 - 8 8 4 ,8 9 2 Tennessee, antievolutioni sm and,372. Seealso Scopestrial Tennyson,Alfred, Lord, 474, 894-89.5 Terrestrialization, in historyof life theories,8 L-82 Testudines, 740 Tetrapods: digit patterns,216, 217f; diversification, 88-89, 88/ Thaxton,Charles,376 Theisticscience, 383 Theophrastus, 422 "Theoryof Population, A" (Spencer), 867 Theory of tbe Earth (Buffon),456 The
TropicalSouthAfrica (Galton),597 Tschermak-Sysenegg, Erich, 896 Tuberculosis, 439 Tunicates, 789,791 Turesson, Gdte,532, 852 Turing, A|an,549,727 Turner,.fohnR. G., 588 Turtles,740.Seea/soGalipagos tortolses T u t t ,J . U | . , 6 5 2 , 6 5 3 TwelveGenomes Project,173 T y l o r ,E . 8 , 8 6 2 Unger,Franz,729-730 Uniramianhypothesis, for crustaceans, 498 Universaldeterrninism, 832 UnseenUniuerse,Tire (Stewartand Tait),353 Urey,Harold,56-58, 733 Urey-Millerexperiment, 575 Use-inheritan ce,673-674 Vacherde Lapouge,Georges,862 \ff., 435,872 Valentine, James Van Valen,Leigh,227, 5 51. Variaticytand Euohiion in Plants (Stebbins), 871, 872, 892-893 Variationt>fAnimalsand Plantsunder (C. Darwin),507 Domestication Vascularplants,diversificationof, 87-88,88/ Velctciraptor, 4 53, 520f Venerealdisease, 440 Veracausa,699, 9 16-917 Vermeij,Geerat,551 VertebratePaleontology(A. S. Romer), 835 Vertebrates. SeeOrigin of vertebrates Vestiges of the Natural History of C,reatien(R. Chambers\,6-7, 8f, 474, 649, 81.9,893-896,903, 9t4 Vicariance allopatricspeciation, 187, 18 8 f Vicariancebiogeography, 450 Vicq-d'Az-yr, Felix,581 Virchow, Rudolf, 626 Virus-mediated process transduction, 679 V i r a l i s m3, 0 , 3 6 3 ,4 4 6 4 4 7 , 6 4 5 , 7 7 3 Vogt,Oskar,885-886 Volcanisnr, massextinctions and, 7r8-719

s77

L)78

Index Vortriige iiber D escendenztb eorie (\Weismann), 909 Voyageof the Beagle,The (C. Darwin), 504-505,903 Vries,Hugo de,748, 850, 852, 896-897 Wdchtershduser, G., 59,62-63 'S(addington, ClonradHal, 216, 403, 5 6 1 f ,8 3 3 , 8 9 8 - 9 0 0 lfade, Michael.|ohn,900-901 'Wagner, Andreas,5 18-519 'Wagner, Giinter, 638 '!fake, David 8' 901-902 Walking.SeeBipedalism 'Wallace, AlfredRussel , 1.4,22-23,29, 5 0 6 ,5 1 1 ,6 3 9 ,8 6 4 ,8 9 5 ,9 0 3 - 9 0 6 ; Batesand,445; biogeography,44T, 448,449f; Cuvierand,502;Jenkirr a n d ,6 6 3 ;L v e l la n d ,8 1 8 - 8 1 9 ; Malthus and,703-704;religion,513, 514; superorganism concept,874 'Wallace, Bruce,33f, 34f Wallace's line,448, 449f,904 '!7alsh, Bruce,70 I Wanderingpolygyny, 242 Warfield,B. B., 3.58,363-364 "Warm little pond" term,49,60-61 'Water, origin of life and, 51-54 Vy'ater Babies,Tbe (Kingsley),650 'Watson, James,906-909 Watson,John 8., 541 'Weber, Bruce,327 Wedekind,C., 250 Wedgwood, .fosiah,9/, 504, 508 'Weischaus, Eric, 529 'Weismann, AugustFriedrichLeopold, 333-334,545, 570,674, 832, 868, 909-9rO 'Weldon, W. F. R.. 537,754,801-802, 910-913 \ W e l l sG, . P . , 6 4 6 \ W e l l sH, . G . , 6 4 6 Wells,Jonathan,377 V{eltrdthsel, Der (Haeckel),622, 626 West-Eberhar d, M. J., 247 lilhat ls Darwinism?(Hodge),357 Vlhat Is Lrlei (Schrddinger), 886 W h e w e l lW , i l l i a m ,l 5 i , 1 8 f ,3 5 ' t , 7 7l , 894,973-919 'Whitcomb, John C., lr., 359,373,428, 842 White, Andrew, 350-352 White,EllenG., 359, 842

\White,Michael D., 199,742-744 J. 'Whitman, Charles,215 'Whooping 439 c
creationis Young-earth 377-378.388-390 Zahm,-John,35.3 Zielren,Theodor,832 Zimrner,Karl, 886

Index

D., 199,742-744 ,216 439 e l ,3 4 8 ,3 5 7 , 6 3 9 , t21, 920f 906 , r97 . . ,8 8 9 c.,239,315,320, 5 6 8 ,5 7 0 ,5 7 2 , 762, 890,921-923 928 95

s,827 larl,316,3I7, Beecher,751 ).,37,4344, 5 4 3 , 7 4 88, 5 9 , 889,907,923-926 Cer,358 3 5 5 ,3 6 3 in the \4anifested ',reation,Tbe (Ray), , 5 4 0 5, 7 6 , 6 7 9 , 7 3 4 , y 49, 54 uerEuolued,The TJ

, 1l - 8 1 3 ur Smith8 r, RonaldGeorge,532 irederick,358,364 1 , 3 2 , 3 1 4 ,5 9 4 , sonand,446447; 9; chance,477; rd, 483; Dobzhansky 604; "Evolutionin rulations,"560-5621, 0; Ford and,587; Kimura 471,,627-628; :leand,675;Simpson V e r oC . ,2 3 9 , 4 0 3 ,6 7 I

tV.,930-931 tI

550 1

(YEC)'3 7 6 . creationism Young-earth 377-378,388-390

Zinder, Norton, 679 Zinj,677-678 Zoological Philosophy (l-amarck),672,

Zahm,John,353 Ziehen,Theodor,832 Ztntmer,Karl, 886

932-934,933f (E.Darwin),504,509,-5L0 Zoonomia 288 Zoonotic diseases,

979