History of evolutionary thought 788565 226171899 2008-07-17T03:55:26Z Rusty Cashman 2010902 /* Chinese thought */ mention century Zhuangzi lived during per FAC {{otheruses4|the history of evolutionary thought in biology|the history of evolutionary thought in the social sciences|social evolutionism|the history of evolutionary thought generally|evolutionism}} [[Image:Tree of life by Haeckel.jpg|thumb|right|250px|The Tree of Life as depicted by [[Ernst Haeckel]] in ''The Evolution of Man'' (1879) illustrates the 19th-century view that evolution was a progressive process leading towards man.]] '''Evolutionary thought''', the idea that species change over time, has roots in antiquity, in ideas of the [[Greek philosophy|Greeks]], [[Roman Empire|Romans]], [[Chinese philosophy|Chinese]] and [[Early Islamic philosophy|Muslims]]. However, until the 18th century, [[Western world|Western]] biological thinking was dominated by [[essentialism]], the idea that living forms are unchanging. During the [[Age of Enlightenment|Enlightenment]], evolutionary [[cosmology]] and the [[mechanical philosophy]] spread from the physical sciences to [[natural history]]. Naturalists began to focus on the variability of species and the emergence of [[paleontology]] with the concept of [[extinction]] undermining the static view of nature. In the early 19th century, [[Jean-Baptiste Lamarck]] proposed his theory of the [[transmutation of species]], which was the first fully formed scientific theory of [[evolution]]. The evolutionary theory often referred to as [[Darwinism]] was first put forward by [[Charles Darwin]] and [[Alfred Russel Wallace]], and it was explained in detail in Darwin's ''[[On the Origin of Species]]'' (1859). Unlike Lamarck's theory, Darwinism proposed [[common descent]] and a branching [[Tree of life (science)|tree of life]]. It was based on the idea of [[natural selection]], and it synthesized evidence from [[animal husbandry]], [[biogeography]], [[geology]], [[morphology (biology)|morphology]], and [[embryology]]. Darwin's work led to the rapid acceptance of evolution, but the mechanism he proposed, [[natural selection]], was not widely accepted until the 1940s. Most biologists argued that other factors drove evolution, such as [[Inheritance of acquired characters|inheritance of acquired characteristics]] (neo-Lamarckism), an innate drive for change ([[orthogenesis]]), or sudden large mutations ([[saltationism]]). The synthesis of natural selection with [[Mendelian inheritance| Mendelian genetics]] during the 1920s and 1930s, founded the new discipline of [[population genetics]]. Throughout the 1930s and 1940s, population genetics became integrated with other branches of biology, finally resulting in a unified theory of evolution&mdash;the [[modern evolutionary synthesis]]. Following the establishment of [[evolutionary biology]], studies of [[mutation]] and [[genetic diversity|variation]] in natural populations, combined with [[biogeography]] and [[systematics]], led to sophisticated mathematical and causal models of evolution. Paleontology and [[comparative anatomy]] allowed more detailed reconstructions of the [[history of life]]. After the rise of [[molecular genetics]] in the 1950s, the field of [[molecular evolution]] developed, based on [[DNA]], [[RNA]], and [[protein sequence]]s. The [[gene-centered view of evolution]] then rose to prominence in the 1960s, followed by the [[neutral theory of molecular evolution]], sparking debates over [[adaptationism]], the [[units of selection]], and the importance of [[genetic drift]]. In the late 20th century, genetic [[sequencing]] led to a reorganization of the tree of life into the [[three-domain system]], and the newly recognized factors of [[symbiogenesis]] and [[horizontal gene transfer]] have introduced yet more complexity into evolutionary history. {{evolution3}} ==Antiquity== ===Greek thought=== Some [[Greek philosophers]] discussed ideas that involved forms of organic evolution. [[Anaximander]] (c. 610–546 BC) claimed that life had originally developed in the sea and only later moved onto land, and [[Empedocles]] (c. 490–430 BC) also discussed a non-supernatural origin for living things.<ref>{{cite web|last=Campbell|first=Gordon|title=Empedocles|publisher=Internet Encyclopedia of Philosophy|url=http://www.iep.utm.edu/e/empedocl.htm#H4|accessdate=2008-07-15}}</ref> Empedocles even suggested a form of [[natural selection]], which Aristotle summarized as,"Wherever then all the parts came about just what they would have been if they had come be for an end, such things survived, being organized spontaneously in a fitting way; whereas those which grew otherwise perished and continue to perish..." <ref>{{cite web|last=Hardie|first=R.P.|coauthors=R. K. Gaye|title=Physics by Aristotle|url=http://classics.mit.edu/Aristotle/physics.2.ii.html|accessdate=2008-07-15}}</ref> [[Plato]] (427/8–347/8 BC) was, in the words of biologist and historian [[Ernst Mayr]], "the great antihero of evolutionism,"<ref> {{wikiref |id=Mayr-1982|text= Mayr 1982 p. 304}}</ref> as he established the philosophy of [[essentialism]], which he called the [[theory of forms]]. This theory holds that objects observed in the real world are only ''reflections'' of a limited number of [[essence]]s (''eide''). Variation is merely the result of an imperfect reflection of these constant essences. In his ''[[Timaeus (dialogue)|Timaeus]]'', Plato set forth the idea that [[God]] had created the [[cosmos]] and everything in it because He is good, and hence, "... free from jealousy, He desired that all things should be as like Himself as they could be." God created all conceivable forms of life, since "... without them the universe will be incomplete, for it will not contain every kind of animal which it ought to contain, if it is to be perfect." This idea, that all potential forms of life are essential to a perfect creation, is called the [[plenitude principle]], and it greatly influenced Christian thought.<ref name=oet>{{cite web | last = Johnston | first = Ian | title =Section Three: The Origins of Evolutionary Theory | work =. . . And Still We Evolve: A Handbook on the History of Modern Science | publisher =Liberal Studies Department, Malaspina University College | date =1999 | url =http://www.mala.bc.ca/~johnstoi/darwin/sect3.htm | accessdate =2007-08-11 }}</ref> [[Aristotle]] (384–322 BC), one of the most influential of the Greek philosophers, is the earliest natural historian whose work has come down to us in any real detail. His writings on biology were the result of his research into natural history on the isle of [[Lesbos]], and have survived in the form of four books, usually known by their [[Latin]] names, ''[[On the Soul|De anima]]'' (on the essence of life), ''[[History of Animals|Historia animalium]]'' (inquiries about animals), ''[[Generation of Animals|De generatione animalium]]'' (reproduction), and ''[[Parts of Animals|De partibus animalium]]'' (anatomy). These works contain some remarkably astute observations and interpretations by Aristotle, along with sundry myths and mistakes&mdash;reflecting the uneven state of knowledge during his time.<ref name="Singer_SHB"> {{wikiref |id=Singer-1931|text=Singer 1931}}</ref> However, for [[Charles Singer]], "Nothing is more remarkable than [Aristotle's] efforts to [exhibit] the relationships of living things as a ''scala naturæ''".<ref name="Singer_SHB"/> This ''scala naturæ'', described in ''History of Animals'', classified organisms in relation to a hierarchical "Ladder of Life" or "Chain of Being", placing them according to complexity of structure and function, with organisms that showed greater vitality and ability to move described as "higher organisms".<ref name=oet/> ===Chinese thought=== Ideas on evolution were expressed by ancient [[Chinese philosophy|Chinese thinkers]] such as [[Zhuangzi]] (Chang Tzu), who lived around the 4th century BC. According to [[Joseph Needham]], [[Taoism]] explicitly denied the fixity of biological species.<ref>{{wikiref|id=Needham-1995|text= Needham and Ronan 1995 p. 101}}</ref> Instead, humans, nature and the heavens were seen as existing in a state of "constant transformation" known as the [[Tao]].<ref>{{Cite web |author = Miller, James |title = Daoism and Nature |publisher = Royal Asiatic Society |date=January 8, 2008 |url = http://www.jamesmiller.ca/RAS%20lecture%20on%20daoism%20and%20nature.pdf|accessdate=2008-07-15}}</ref> ===Roman thought=== Titus [[Lucretius]] Carus (d. 50 BC), the Roman [[Epicurean]] and [[atomist]], wrote the poem ''[[On the Nature of Things]]'' (''De rerum natura''), describing the development of the living Earth in stages: from atoms colliding in the void as swirls of dust to early plants and animals springing from the early Earth's substance, then a succession of animals, including a series of progressively less brutish humans. Lucretius may be seen as the earliest believer in [[hard inheritance]]. He said, "For if each organism had not its own genetic bodies, how could we with certainty assign each to its mother?".<ref> {{wikiref|id=Darlington 1959|text=Darlington 1959}} </ref> The essence of Lucretius' ideas was naturalism, and the avoidance of supernatural interventions or explanations. ==Middle Ages== ===Islamic thought and the struggle for existence=== {{main|Early Islamic philosophy#Evolution|l1=Early Islamic philosophy – Evolution}} Whereas Greek and Roman evolutionary ideas died out in Europe after the fall of the [[Roman Empire]], they were not lost to [[Islamic science|Islamic scientists]] and [[Early Islamic philosophy|philosophers]]. In the [[Islamic Golden Age]], early theories on evolution were taught in Islamic schools.<ref name="Draper" /> [[John William Draper]], the 19th-century scientist, philosopher and historian, discussed the 12th-century writings of [[al-Khazini]] as part of what he called the "[[Mohammedan]] theory of evolution". He compared these early theories to the modern [[Darwinism|Darwinian]] theory of evolution of his time, arguing that the former were developed "... much farther than we are disposed to do, extending them even to inorganic or mineral things."<ref name="Draper">{{wikiref|id=Draper-1878|text=Draper 1878 pp. 154–155, 237}}</ref> The first Muslim biologist and philosopher to put forth detailed speculations about evolution was the [[Afro-Arab]] writer [[al-Jahiz]] in the 9th century. He considered the effects of the environment on an animal's chances for survival, and described the [[On the Origin of Species#Struggle for existence, and natural selection|struggle for existence]].<ref>Conway Zirkle (1941). Natural Selection before the "Origin of Species", ''Proceedings of the American Philosophical Society'' '''84''' (1), pp. 71–123.</ref><ref name="IslamicQuarterly">Mehmet Bayrakdar (Third Quarter, 1983). "Al-Jahiz And the Rise of Biological Evolutionism", ''The Islamic Quarterly''. [[London]]. [http://www.salaam.co.uk/knowledge/al-jahiz.php]</ref> [[Ibn Miskawayh]]'s ''al-Fawz al-Asghar'' and the [[Brethren of Purity]]'s ''[[Encyclopedia of the Brethren of Purity]]'' (''The Epistles of Ikhwan al-Safa'') expressed ideas about how species developed: from matter into vapor and thence to water, then minerals into plants and then animals, leading to apes and, finally, humans.<ref>[[Muhammad Hamidullah]] and Afzal Iqbal (1993), ''The Emergence of Islam: Lectures on the Development of Islamic World-view, Intellectual Tradition and Polity'', pp. 143–144. Islamic Research Institute, Islamabad.</ref><ref name=Hart>Eloise Hart, ''Pages of Medieval Mideastern History''. ([[cf.]] Isma'ili, Yezidi, Sufi, [http://www.ismaili.net/mirrors/Ikhwan_04/brotherpur.html The Brethren Of Purity], Ismaili Heritage Society)</ref> The polymath [[Ibn al-Haytham]] wrote a book in which he argued for [[evolutionism]] (although not natural selection). Numerous other Islamic scholars and scientists, such as [[Abū Rayhān al-Bīrūnī]], [[Nasir al-Din Tusi]], and [[Ibn Khaldun]] discussed and developed these ideas. Translated into [[Latin]], these works began to appear in the West after the [[Renaissance]] and may have had an impact on Western science.<ref name="IslamicQuarterly"/> ===Christian thought and the great chain of being=== [[Image:Great Chain of Being 2.png|thumb|left|Drawing of the [[great chain of being]] is from ''Retorica Christiana'' (1579) by Didacus Valdes.]] During the [[Dark Ages]], Greek classical learning was all but lost to the West. However, contact with the [[Islamic Golden Age|Islamic world]], where Greek manuscripts were preserved and elaborated on, soon led to a massive spate of [[Latin translations of the 12th century|Latin translations in the 12th century]]. Europeans were thus re-introduced to the works of Plato and Aristotle, as well as to [[Early Islamic philosophy|Islamic thought]]. [[Christian philosophy|Christian thinkers]] combined Aristotlean classification with Plato's ideas of the goodness of God, and of all potential life forms being present in a perfect creation, to organize all inanimate, animate, and spiritual beings into a huge interconnected system: the ''scala naturæ'', or [[great chain of being]]. Within this system, everything that existed could be placed in order, from "lowest" to "highest", with [[Hell]] at the bottom and God at the top&mdash;below God, an angelic hierarchy marked by the orbits of the planets, mankind in an intermediate position, and worms the lowest of the animals. As the universe was ultimately perfect, the great chain was also perfect. There were no empty links in the chain, and no link was represented by more than one species. Therefore no species could ever move from one position to another. Thus, in this Christianized version of Plato's perfect universe, species could never change, but must remain forever fixed, in accordance with the text of ''[[Book of Genesis|Genesis]]''. For humans to forget their position was seen as sinful, whether they behaved like lower animals or aspired to a higher station than was given them by their Creator. Creatures on adjacent steps were expected to closely resemble each other, an idea expressed in a saying which [[Charles Darwin]] often quoted: {{lang|la|''natura non facit saltum''}} ("nature does not make leaps").<ref name=oet/> This basic concept of the great chain of being greatly influenced the thinking of [[Western culture|Western civilization]] for centuries (and still has an influence today). It also formed a part of the [[teleological argument|argument from design]] presented by [[natural theology]]. As a classification system, it became the major organizing principle and foundation of the emerging science of [[biology]] in the 17th and 18th centuries.<ref name=oet/> ==Renaissance and Enlightenment== {{Main article|Evolutionary ideas of the renaissance and enlightenment}} [[Image:BelonBirdSkel.jpg|thumb|[[Pierre Belon]] compared the skeletons of birds and humans in his ''Book of Birds'' (1555).]] Some [[evolutionism|evolutionist]] theories explored between 1650 and 1800 postulated that the universe, including life on earth, had developed mechanically, entirely without divine guidance. Around this time, the [[mechanical philosophy]] of [[René Descartes]] began to encourage the machine-like view of the universe which would come to characterise the [[scientific revolution]].<ref> {{wikiref|id=Bowler-2003|text=Bowler 2003 pp. 33-38}} </ref> However, most contemporary theories of evolution, such of those of [[Gottfried Leibniz]] and [[J. G. Herder]], held that evolution was a fundamentally ''spiritual'' process.<ref>Schelling, ''System of Transcendental Idealism'', 1800</ref> In 1751, [[Pierre Louis Maupertuis]] veered toward more [[materialism|materialist]] ground. He wrote of natural modifications occurring during reproduction and accumulating over the course of many generations, producing races and even new species, and he anticipated in general terms the idea of natural selection.<ref> {{wikiref|id=Bowler-2003|text= Bowler 2003 pp. 73–75}}</ref> Later in the 18th century, [[G. L. L. Buffon]] suggested that what most people referred to as species were really just well-marked varieties modified from an original form by environmental factors. For example, he believed that lions, tigers, leopards and house cats might all have a common ancestor. He speculated that the 200 or so species of mammals then known might have descended from as few as 38 original forms. Buffon’s evolutionary ideas were strictly limited; he believed each of the original forms had arisen through spontaneous generation and that they were shaped by "internal moulds" that limited the amount of change.<ref> {{wikiref|id=Bowler-2003|text= Bowler 2003 pp. 75–80}}</ref><ref>{{wikiref|id=Larson-2004|text= Larson 2004 pp. 14–15}}</ref> Between 1767 and 1792, [[James Burnett, Lord Monboddo]] included in his writings not only the concept that man had descended from primates, but also that, in response to the environment, creatures had found methods of transforming their characteristics over long time intervals.<ref>{{wikiref|id=Henderson-2000| text=Henderson 2000}}</ref> Charles Darwin’s grandfather, [[Erasmus Darwin]], published ''[[Zoönomia]]'' in 1796, which suggested that "all warm-blooded animals have arisen from one living filament".<ref> {{wikiref|id=Darwin-1818|text=Darwin, Erasmus 1818 Vol I section XXXIX}}</ref> In his 1802 poem ''Temple of Nature'', he described the rise of life from minute organisms living in the mud to a state of modern diversity.<ref>{{wikiref|id=Darwin-1825|text= Darwin, Erasmus 1825 p. 15}}</ref><br /></blockquote> ==19th century before ''On the Origin of Species''== [[Image:Owen geologic timescale.png|thumb|left|Diagram of the geologic timescale from an 1861 book by [[Richard Owen]] showing the appearance of major animal types]] ===Paleontology and geology=== {{seealso|History of paleontology}} In 1796, [[Georges Cuvier]] published his findings on the differences between living [[elephant]]s and those found in the [[fossil]] record. His analysis demonstrated that [[mammoth]]s and [[mastodon]]s were distinct species different from any living animal, effectively ending a long-running debate over the possibility of the extinction of a species.<ref> {{wikiref|id=Larson-2004|text = Larson 2004 p. 7}} </ref> [[William Smith (geologist)|William Smith]] began the process of ordering [[Stratum|rock strata]] by examining fossils in the layers while he worked on his geologic map of [[England]]. Independently, in 1811, Georges Cuvier and [[Alexandre Brongniart]] published an influential study of the geologic history of the region around Paris, which was based on the [[Stratigraphy|stratigraphic]] succession of layers of rock. These works helped establish the antiquity of the earth.<ref> {{wikiref|id=Bowler-2003|text=Bowler 2003 p. 113}} </ref> Cuvier advocated [[catastrophism]] to explain the patterns of extinction and [[Principle of faunal succession|faunal succession]] revealed by the fossil record. Knowledge of the fossil record continued to advance rapidly during the first few decades of the 19th century. By the 1840s, the outlines of the [[Geologic time scale|geologic timescale]] were becoming clear, and in 1841 [[John Phillips (geologist)|John Phillips]] named three major eras, based on their predominant fauna: the [[Paleozoic]], dominated by marine [[invertebrate]]s and fish, the [[Mesozoic]], the age of reptiles, and the current [[Cenozoic]] age of mammals. This progressive picture of the history of life was accepted even by conservative English geologists like [[Adam Sedgwick]] and [[William Buckland]]; however, also like Cuvier, they attributed the progression to repeated catastrophic episodes of extinction followed by new episodes of creation.<ref> {{wikiref|id=Larson-2004|text = Larson 2004 pp. 29–38}} </ref> Unlike Cuvier, Buckland and some other advocates of [[natural theology]] among British geologists made efforts to explicitly link the last catastrophic episode proposed by Cuvier to the [[Deluge (mythology)#Hebrew|biblical flood]].<ref> {{wikiref|id=Bowler-2003|text=Bowler 2003 pp. 115–116}} </ref><ref name=Darwindesign>{{cite web|url=http://www.darwinproject.ac.uk/content/view/110/104/|title=Darwin and design: historical essay|publisher=Darwin Correspondence Project|accessdate=2008-01-17}}</ref> From 1830 to 1833, [[Charles Lyell]] published his multi-volume work ''[[Principles of Geology]]'', which advocated a [[uniformitarianism (science)|uniformitarian]] alternative to the catastrophic theory of geology. Lyell claimed that, rather than being the products of cataclysmic (and possibly supernatural) events, the geologic features of the earth are better explained as the result of the same [[gradualism|gradual]] geologic forces observable in the present day&mdash;but acting over immensely long periods of time. Although Lyell opposed evolutionary ideas (even questioning the consensus that the fossil record demonstrates a true progression), his concept that the earth was shaped by forces working gradually over an extended period, and the immense age of the earth assumed by his theories, would strongly influence future evolutionary thinkers such as [[Charles Darwin]].<ref name="Bowler129-134"> {{wikiref|id=Bowler-2003|text=Bowler 2003 pp. 129–134}} </ref> ===Transmutation of species=== {{main article|Transmutation of species}} [[Image:Vestiges dev diag.jpg|thumb|right|Diagram from the 1844 book ''Vestiges of the Natural History of Creation'' by Robert Chambers shows a model of development where fish (F), reptiles (R), and birds (B) represent branches from a path leading to mammals (M).]] [[Jean-Baptiste Lamarck]] proposed, in his ''[[Philosophie Zoologique]]'' of 1809, a theory of the transmutation of species. Lamarck did not believe that all living things shared a common ancestor but rather that simple forms of life were created continuously by [[spontaneous generation]]. He also believed that an innate life force drove species to become more complex over time, advancing up a linear ladder of complexity that was related to the great chain of being. Lamarck recognized that species were adapted to their environment. He explained this by saying that the same innate force driving increasing complexity caused the organs of an animal (or a plant) to change based on the use or disuse of that organ, just as muscles are affected by exercise. He argued that these changes would be inherited by the next generation and produce slow adaptation to the environment. It was this secondary mechanism of adaptation through the inheritance of acquired characteristics that would become known as [[Lamarckism]] and would influence discussions of evolution into the 20th century.<ref> {{wikiref|id=Bowler-2003|text= Bowler 2003 pp. 86–94}} </ref><ref> {{wikiref|id=Larson-2004|text= Larson 2004 pp. 38–41}} </ref> A radical British school of comparative anatomy that included the [[anatomist]] [[Robert Edmund Grant|Robert Grant]] was closely in touch with Lamarck's school of French ''Transformationism'', which contained scientists such as [[Étienne Geoffroy Saint-Hilaire]]. Grant developed Lamarck's and Erasmus Darwin's ideas of [[Transmutation of species|transmutation]] and [[evolutionism]], investigating [[homology (biology)|homology]] to prove [[common descent]]. As a young student [[Charles Darwin]] joined Grant in investigations of the life cycle of marine animals. In 1826 an anonymous paper, probably written by [[Robert Jameson]], praised Lamarck for explaining how higher animals had “evolved” from the simplest worms, which was the first use of the word “evolved” in a modern sense.<ref> {{wikiref|id=Desmon-1994|text=Desmond and Moore 1993 p. 40}} </ref><ref name="Bowler120-129"> {{wikiref|id=Bowler-2003|text= Bowler 2003 pp. 120–129}} </ref> In 1844, the Scottish publisher [[Robert Chambers]] anonymously published an influential, and extremely controversial book of popular science entitled ''[[Vestiges of the Natural History of Creation]]''. This book proposed an evolutionary scenario for the origins of the Solar System and life on earth. It claimed that the fossil record showed a progressive ascent of animals with current animals being branches off a main line that lead progressively to humanity. It implied that the transmutations lead to the unfolding of a preordained plan that had been woven into the laws that governed the universe. In this sense it was less completely materialistic than the ideas of radicals like Robert Grant, but its implication that humans were just the last step in the ascent of animal life incensed many conservative thinkers. The high profile of the public debate over ''Vestiges'', with its depiction of evolution as a progressive process, would greatly influence the perception of Darwin's theory a decade later.<ref> {{wikiref|id=Bowler-2003|text = Bowler 2003 pp. 134–138}} </ref><ref> {{wikiref|id=Bowler-2005|text=Bowler and Morus 2005 pp. 142–143}} </ref> Ideas about the transmutation of species were associated with the radical materialism of the [[Age of Enlightenment|Enlightenment]] and were attacked by more conservative thinkers. [[Georges Cuvier]] attacked the ideas of Lamarck and Geoffroy Saint-Hilaire, agreeing with Aristotle that species were immutable. Cuvier believed that the individual parts of an animal were too closely correlated with one another to allow for one part of the anatomy to change in isolation from the others, and argued that the fossil record showed patterns of catastrophic extinctions followed by re-population, rather than gradual change over time. He also noted that drawings of animals and animal mummies from Egypt, which were thousands of years old, showed no signs of change when compared with modern animals. The strength of Cuvier's arguments and his scientific reputation helped keep transmutational ideas out of the mainstream for decades.<ref> {{wikiref|id=Larson-2004|text= Larson 2004 pp. 5–24}} </ref> [[Image:Vertebrate archetype.jpg|thumb|left|This 1847 diagram by Richard Owen shows his conceptual archetype for all vertebrates.]] In Britain the philosophy of [[natural theology]] remained influential. [[William Paley]]'s 1802 book ''Natural Theology'' with its famous [[watchmaker analogy]] had been written at least in part as a response to the transmutational ideas of [[Erasmus Darwin]].<ref> {{wikiref|id=Bowler-2003|text=Bowler 2003 pp. 103–104}} </ref> Geologists influenced by natural theology, such as Buckland and Sedgwick, made a regular practice of attacking the evolutionary ideas of Lamarck, Grant, and ''The Vestiges of the Natural History of Creation''.<ref> {{wikiref|id=Larson-2004|text= Larson 2004 pp. 37–38}} </ref><ref> {{wikiref|id=Bowler-2003|text=Bowler 2003 p. 138}} </ref> Although the geologist [[Charles Lyell]] opposed scriptural geology he also believed in the immutability of species, and in his ''Principles of Geology'' (1830–1833), he criticized Lamarck's theories of development.<ref name="Bowler129-134"/> Idealists such as [[Louis Agassiz]] and [[Richard Owen]] believed that each species was fixed and unchangeable because it represented an idea in the mind of the creator. They believed that relationships between species could be discerned from developmental patterns in [[embryology]], as well as in the fossil record, but that these relationships represented an underlying pattern of divine thought, with progressive creation leading to increasing complexity and culminating in humanity. Owen developed the idea of "archetypes" in the Divine mind that would produce a sequence of species related by anatomical homologies, such as [[vertebrate]] limbs. Owen led a public campaign that successfully marginalized Robert Grant in the scientific community. Darwin would make good use of the homologies analyzed by Owen in his own theory, but the harsh treatment of Grant, and the controversy surrounding ''Vestiges'', would contribute to his decision to delay publishing his ideas.<ref name="Bowler120-129"/><ref>{{wikiref|id=Larson-2004|text= Larson 2004 pp. 42–46}}</ref> ===Anticipations of natural selection=== Several writers anticipated aspects of Darwin's theory, and in the third edition of ''[[On the Origin of Species]]'' published in 1861 Darwin named those he knew about in an introductory appendix, ''An Historical Sketch of the Recent Progress of Opinion on the Origin of Species'', which he expanded in later editions.<ref>{{harvnb|Darwin|1861|p=[http://darwin-online.org.uk/content/frameset?itemID=F381&viewtype=text&pageseq=20 xiii]}}</ref> In 1813, [[William Charles Wells]] read before the [[Royal Society]] essays assuming that there had been evolution of humans, and recognising the principle of [[natural selection]]. Charles Darwin and Alfred Russel Wallace were unaware of this work when they jointly published the theory in 1858, but Darwin later acknowledged that Wells had recognised the principle before them, writing that the paper "An Account of a White Female, part of whose Skin resembles that of a Negro" was published in 1818, and "he distinctly recognises the principle of natural selection, and this is the first recognition which has been indicated; but he applies it only to the races of man, and to certain characters alone."<ref>{{harvnb|Darwin|1866|p=[http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F385&pageseq=21 xiv]}}</ref> When Darwin was developing his theory, he was influenced by [[A. P. de Candolle|Augustin de Candolle]]'s ''natural system'' of classification, which laid emphasis on the war between competing species.<ref>{{wikiref|id=Bowler-2003|text=Bowler 2003 p. 151}}</ref><ref>{{harvnb|Darwin|1859|p=[http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F373&pageseq=77 62]}}</ref> [[Patrick Matthew]] wrote in the obscure book ''Naval Timber & Arboriculture'' (1831) of "continual balancing of life to circumstance. ... [The] progeny of the same parents, under great differences of circumstance, might, in several generations, even become distinct species, incapable of co-reproduction."<ref>{{cite web|last=Matthew|first=Patrick|title=Nature's law of selection. Gardeners' Chronicle and Agricultural Gazette |url=http://darwin-online.org.uk/content/frameset?itemID=A143&viewtype=text&pageseq=1|publisher=The Complete Works of Charles Darwin Online|date=1860|accessdate=2007-11-01}}</ref> Charles Darwin discovered this work after the initial publication of the ''Origin''. In the brief historical sketch that Darwin included in the 3rd addition he says "Unfortunately the view was given by Mr. Matthew very briefly in an Appendix to a work on a different subject ... He clearly saw, however, the full force of the principle of natural selection."<ref>{{harvnb|Darwin|1861|p=[http://darwin-online.org.uk/content/frameset?itemID=F381&viewtype=text&pageseq=21 xiv]}}</ref> Tt is possible to look through the history of biology from the Ancient Greeks onwards and discover anticipations of almost all of Darwin's key ideas. However, there are a couple of major differences between Darwin and his predecessors. Perhaps the most important difference is that the vast majority of Darwin's predecessors seem to have failed to understand the implications of their own ideas. As an example, Matthew chose to relegate his idea on natural selection to the appendix of a work on an unrelated subject, and William Charles Wells seems to have made little or no attempts to publicise his ideas beyond reading them to the Royal Society. Secondly, despite having enunciated the basic idea of natural selection, precursors of Darwin either assumed that it was self-evidently true, or gave merely ''logical'' arguments for its importance and failed to provide any [[empirical]] data. In other words, the anticipations of Darwin were merely formal and verbal.<ref> {{wikiref|id=Bowler-2003|text=Bowler 2003 p. 158}} </ref> [[T. H. Huxley]] pointed out in his essay on the reception of the ''Origin of Species'': <blockquote> The suggestion that new species may result from the selective action of external conditions upon the variations from their specific type which individuals present and which we call spontaneous because we are ignorant of their causation is as wholly unknown to the historian of scientific ideas as it was to biological specialists before 1858. But that suggestion is the central idea of the ''Origin of Species'', and contains the quintessence of Darwinism.<ref>{{cite web|last=Huxley|first=Thomas Henry|title=''The Reception of the Origin of Species'' |url=http://infomotions.com/etexts/gutenberg/dirs/etext00/oroos10.htm|publisher=Project Gutenberg|date=1895|accessdate=2007-11-02}}</ref> </blockquote> [[Image:Darwins first tree.jpg|right|thumb|250px|Darwin's first sketch of an evolutionary tree from his ''First Notebook on Transmutation of Species'' (1837)]] ===Natural selection=== {{main|Inception of Darwin's theory|Development of Darwin's theory|Publication of Darwin's theory}} The [[biogeography|biogeographical]] patterns Charles Darwin observed in places such as the [[Galapagos islands]] during [[Second voyage of HMS Beagle|the voyage of the Beagle]] caused him to doubt the fixity of species, and in 1837 Darwin started the first of a series of secret notebooks on [[Transmutation of species|transmutation]]. Darwin's observations lead him to view transmutation as a process of divergence and branching, rather than the ladder-like progression envisioned by Lamarck and others. In 1838 he read the new 6th edition of [[An Essay on the Principle of Population]], written in the late 1700s by [[Thomas Malthus]]. Malthus' idea of population growth leading to a struggle for survival combined with Darwin's knowledge on how breeders selected traits, led to the [[inception of Darwin's theory]] of [[natural selection]]. Darwin did not publish his ideas on evolution for 20 years. However he did share them with certain other naturalists and friends, starting with [[Joseph Dalton Hooker|Joseph Hooker]] with whom he discussed his unpublished 1844 essay on natural selection. During this period he used the time he could spare from his other scientific work to slowly refine his ideas and, aware of the intense controversy around transmutation, amass evidence to support them.<ref>{{wikiref|id=Bowler-2005|text=Bowler and Morus pp. 129–149}}</ref><ref>{{wikiref|id=Larson-2004|text=Larson 2004 pp. 55–71}}</ref> <ref>{{cite web|last=van Wyhe|first=John|title=Mind the gap: Did Darwin avoid publishing his theory for many years?|url=http://darwin-online.org.uk/people/van_Wyhe_2007_Mind_the_gap_did_Darwin_avoid_publishing_his_theory.pdf|publisher=Notes and Records of the Royal Society|accessdate=2008-07-16}}</ref> Unlike Darwin, [[Alfred Russel Wallace]], influenced by the book ''Vestiges of the Natural History of Creation'', already suspected that transmutation of species occurred when he began his career as a naturalist. By 1855 his biogeographical observations during his field work in [[South America]] and the [[Malay Archipelago]] made him confident enough in a branching pattern of evolution to publish a paper that stated that every species originated in close proximity to an already existing closely allied species. Once again it was consideration of how the ideas of Malthus might apply to animal populations that lead Wallace to conclusions very similar to the ones reached by Darwin about the role of natural selection. In February 1858 Wallace, unaware of Darwin's unpublished ideas, wrote up his thoughts into an essay and mailed them to Darwin, asking for his opinion. The result was [[On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection|the joint publication in July]] of an extract from Darwin's 1844 essay along with Wallace's letter. Darwin also began work in earnest on ''The Origin of Species'', which he would publish in 1859.<ref>{{wikiref|id=Bowler-2003|text=Bowler 2003 pp. 173–176}}</ref> [[Image:Marsh Huxley horse.png|thumb|left|200px|Diagram by [[O.C. Marsh]] of the evolution of horse feet and teeth over time as reproduced in T.H Huxley's 1876 book ''Professor Huxley in America'']] ==1859–1930s: Darwin and after Darwin== {{see also|reaction to Darwin's theory}} While transmutation of species was accepted by a sizable number of scientists before 1859, it was the publication of Charles Darwin's ''[[On the Origin of Species]]'' that fundamentally transformed the debate over biological origins. Darwin argued that his branching version of evolution explained a wealth of facts in biogeography, anatomy, embryology, and other fields of biology. He also provided the first cogent mechanism by which evolutionary change could persist: his theory of natural selection.<ref name="Larson79-111">{{wikiref|id=Larson-2004|text=Larson 2004 pp. 79–111}}</ref> One of the first and most important naturalists to be convinced by ''Origin'' was the British anatomist [[Thomas Henry Huxley]]. Huxley recognized that unlike the earlier transmutational ideas of Lamarck and ''Vestiges'', Darwin's theory provided a mechanism for evolution without supernatural involvement. Huxley would make advocacy of evolution a cornerstone of the program of the [[X-club]] to reform and professionalize science by displacing [[natural theology]] with [[methodological naturalism]], ending the domination of British natural science by the clergy. By the early 1870s in English-speaking countries, thanks partly to these efforts, evolution had become the mainstream scientific explanation for the origin of species.<ref name="Larson79-111"/> In his campaign for public and scientific acceptance of Darwin's theory, Huxley made extensive use of new evidence for evolution from paleontology. This included evidence that birds had evolved from reptiles, including the discovery of ''[[Archaeopteryx]]'' in Europe, and a number of fossils of primitive birds with teeth found in North America. Another important line of evidence was the finding of fossils that helped trace the [[evolution of the horse]] from its small five-toed ancestors.<ref>{{wikiref|id=Larson-2004|text= Larson 2004 pp. 139–40}}</ref> However, acceptance of evolution among scientists in non-English speaking nations such as France, and the countries of southern Europe and Latin America was slower. An exception to this was Germany, where both [[August Weismann]] and [[Ernst Haeckel]] championed this idea: with Haeckel using evolution to challenge the established tradition of metaphysical idealism in German biology, much as Huxley used it to challenge natural theology in Britain.<ref>{{wikiref|id=Larson-2004|text= Larson 2004 pp. 109–110}}</ref> Darwin's theory succeeded in profoundly shaking scientific opinion regarding the development of life and resulted in a small social revolution. However, this theory could not explain several critical components of the evolutionary process. Namely, Darwin was unable to explain the source of variation in traits within a species, and could not identify a mechanism that could pass traits faithfully from one generation to the next. Darwin's hypothesis of [[pangenesis]], while relying in part on the inheritance of [[Inheritance of acquired characters|acquired characteristics]], proved to be useful for statistical models of evolution that were developed by his cousin [[Francis Galton]] and the "biometric" school of evolutionary thought. This idea was, however, of little use to biologists. ===Application of the theory to humans=== [[Image:Huxley - Mans Place in Nature.png|thumb|250px|right| This illustration was the frontispiece of [[Thomas Henry Huxley]]'s book ''[[Evidence as to Man's Place in Nature]]'' (1863).]] Charles Darwin was aware of the severe reaction in some parts of the scientific community against the suggestion made in ''Vestiges of the Natural History of Creation'' that humans had arisen from animals by a process of transmutation. Therefore he almost completely ignored the topic of [[human evolution]] in ''The Origin of Species''. Despite this precaution, the issue featured prominently in the debate that followed the book's publication. For most of the first half of the 19th century, the scientific community believed that, although geology had shown that the earth and life were very old, human beings had appeared suddenly just a few thousand years before the present. However, a series of archaeological discoveries in the 1840s and 1850s showed stone tools associated with the remains of extinct animals. By the early 1860s, as summarized in Charles Lyell's 1863 book ''Geological Evidences of the Antiquity of Man'', it had become widely accepted that humans had existed during a prehistoric period &ndash; which stretched many thousands of years before the start of written history. This new view of human history was more compatible with an evolutionary origin for humanity than was the older view. On the other hand, at that time there was no fossil evidence to demonstrate human evolution. The only human fossils found before the discovery of [[Java man]] in the 1890s were either of anatomically modern humans, or of [[Neanderthals]] that were too close, especially in the critical characteristic of cranial capacity, to modern humans for them to be convincing intermediates between humans and other primates.<ref name="Bowler207-216">{{wikiref|id=Bowler-2003|text=Bowler 2003 pp. 207–216}}</ref> Therefore the debate that immediately followed the publication of ''The Origin of Species'' centered on the similarities and differences between humans and modern [[apes]]. [[Richard Owen]] vigorously defended the traditional classification, suggested by [[Carolus Linnaeus]] and Cuvier, that placed humans in a completely separate order from any of the other mammals. On the other hand, Huxley sought to demonstrate a close anatomical relationship between humans and apes. In one very famous incident, Huxley showed that Owen was mistaken in claiming that the brains of [[gorillas]] lacked a structure present in human brains. Huxley summarized his argument in his highly influential 1863 book ''Evidence as to Man's place in Nature''. Another viewpoint was advocated by Charles Lyell and Alfred Russel Wallace. They agreed that humans shared a common ancestor with apes, but questioned whether any purely materialistic mechanism could account for some of the differences between humans and apes, especially some aspects of the human mind.<ref name="Bowler207-216"/> In 1871, Darwin published ''[[The Descent of Man, and Selection in Relation to Sex]]'', which contained his views on human evolution. Darwin argued that the differences between the human mind and the minds of the higher animals were a matter of degree rather than of kind. For example, he viewed morality as a natural outgrowth of instincts that were beneficial to animals living in social groups. He believed that all the differences between humans and apes could be explained by a combination of the selective pressures resulting from our ancestors moving from the trees to the plains, and [[sexual selection]]. The debate over human origins, and over the degree of human uniqueness would continue well into the 20th century.<ref name="Bowler207-216"/> ===Alternatives to natural selection=== {{main|The eclipse of Darwinism}} [[Image:Titanothere Osborn.jpg|thumb|left|200px|This photo from Henry Fairfield Osborn's 1918 book ''Origin and Evolution of Life'' shows models depicting the evolution of [[Titanothere]] horns over time, which Osborn claimed was an example of an orthogenic trend in evolution.]] Evolution was widely accepted in scientific circles within a few years of the publication of ''Origin'', but the acceptance of [[natural selection]] as its driving mechanism was much less widespread. The four major alternatives to natural selection in the late 19th century were [[theistic evolution]], [[neo-Lamarckism]], [[orthogenesis]], and [[saltationism]]. Theistic evolution was the idea that God intervened in the process of evolution to guide it in such a way that the living world could still be considered to be designed. However, this idea rapidly fell out of favor among scientists. They became more and more committed to the idea of [[methodological naturalism]] and came to believe that direct appeals to supernatural involvement were scientifically unproductive and a form of [[special pleading]]. By 1900, theistic evolution had completely disappeared from mainstream scientific discussions.<ref name="Larson105-129">{{wikiref|id=Larson-2004|text= Larson 2004 pp. 105–129}}</ref><ref name="Bowler196-250">{{wikiref|id=Bowler-2003|text= Bowler 2003 pp. 196–253}}</ref> In the late 19th century, the term [[neo-Lamarckism]] came to be associated with the position of naturalists who viewed the inheritance of acquired characteristics as the most important evolutionary mechanism. Advocates of this position included the British writer and Darwin critic [[Samuel Butler (novelist)|Samuel Butler]], the German biologist [[Ernst Haeckel]], and the American paleontologist [[Edward Drinker Cope]]. They considered Lamarckism to be philosophically superior to Darwin's idea of selection acting on random variation. Cope looked for, and thought he found, patterns of linear progression in the fossil record. Inheritance of acquired characteristics was part of Haeckel's [[recapitulation theory]] of evolution, which held that the embryological development of an organism repeats its evolutionary history.<ref name="Larson105-129"/><ref name="Bowler196-250"/> Critics of neo-Lamarckism, such as the German biologist [[August Weismann]] and [[Alfred Russel Wallace]], pointed out that no one had ever produced solid evidence for the inheritance of acquired characteristics. Despite these criticisms, neo-Lamarckism remained the most popular alternative to natural selection at the end of the 19th century, and would remain the position of some naturalists well into the 20th century.<ref name="Larson105-129"/><ref name="Bowler196-250"/> Orthogenesis was the [[hypothesis]] that life has an innate tendency to change, in a unilinear fashion, towards ever-greater perfection. It had a significant following in the 19th century, and its proponents included the Russian biologist Leo Berg and the American paleontologist [[Henry Fairfield Osborn]]. Orthogenesis was popular among some paleontologists, who believed that the fossil record showed a gradual and constant unidirectional change. Saltationism was the idea that new species arise as a result of large mutations. It was seen as a much faster alternative to the Darwinian concept of a gradual process of small random variations being acted on by natural selection, and was popular with early geneticists such as [[Hugo DeVries]], [[William Bateson]], and early in his career, [[T. H. Morgan]]. It became the basis of the [[mutation theory]] of evolution.<ref name="Larson105-129"/><ref name="Bowler196-250"/> [[Image:Sexlinked inheritance white.jpg|right|thumb|200px|Diagram from T.H. Morgan's 1919 book ''The Physical Basis of Heredity'', showing the sex-linked inheritance of the white-eyed mutation in ''[[Drosophila melanogaster]]'']] ===Mendelian genetics, biometrics, and mutation=== The rediscovery of [[Gregor Mendel]]'s laws of inheritance in 1900 ignited a fierce debate between two camps of biologists. In one camp were the [[Mendelian]]s, who were focused on discrete variations and the laws of inheritance. They were led by [[William Bateson]] (who coined the word ''[[genetics]]'') and [[Hugo de Vries]] (who coined the word ''[[mutation]]''). Their opponents were the biometricians, who were interested in the continuous variation of characteristics within populations. Their leaders, [[Karl Pearson]] and [[Walter Frank Raphael Weldon]], followed in the tradition of [[Francis Galton]], who had focused on measurement and statistical analysis of variation within a population. The [[Biostatistics|biometrician]]s rejected Mendelian genetics on the basis that discrete units of heredity, such as genes, could not explain the continuous range of variation seen in real populations. Weldon's work with crabs and snails provided evidence that selection pressure from the environment could shift the range of variation in wild populations, but the Mendelians maintained that the variations measured by biometricians were too insignificant to account for the evolution of new species.<ref name="Bowler256-273">{{wikiref|id=Bowler-2003|text= Bowler 2003 pp. 256–273}}</ref><ref name="Larson153-174">{{wikiref|id=Larson-2004|text= Larson 2004 pp. 153–174}}</ref> When [[T. H. Morgan]] began experimenting with breeding the fruit fly ''[[Drosophila melanogaster]]'', he was a saltationist who hoped to demonstrate that a new species could be created in the lab by mutation alone. Instead, the work at his lab between 1910 and 1915 reconfirmed Mendelian genetics and provided solid experimental evidence linking it to chromosomal inheritance. His work also demonstrated that most mutations had relatively small effects, such as a change in eye color, and that rather than creating a new species in a single step, mutations served to increase variation within the existing population.<ref name="Bowler256-273"/><ref name="Larson153-174"/> ==1920s–1940s== {{seealso|Modern evolutionary synthesis}} {{Double image stack|left|Biston.betularia.7200.jpg|Biston.betularia.f.carbonaria.7209.jpg|200|''Biston betularia f. typica'' is the white-bodied form of the [[peppered moth]].|''Biston betularia f. carbonaria'' is the black-bodied form of the peppered moth.}} ===Population genetics=== The Mendelian and biometrician models were eventually reconciled with the development of [[population genetics]]. A key step was the work of the British biologist and statistician [[R.A. Fisher]]. In a series of papers starting in 1918 and culminating in his 1930 book ''Genetical Theory of Natural Selection'', Fisher showed that the continuous variation measured by the biometricians could be produced by the combined action of many discrete genes, and that [[natural selection]] could change [[gene frequencies]] in a population, resulting in evolution. In a series of papers beginning in 1924, another British geneticist, [[J.B.S. Haldane]], applied statistical analysis to real-world examples of natural selection, such as the [[Peppered moth evolution|evolution of industrial melanism in peppered moths]], and showed that natural selection worked at an even faster rate than Fisher assumed.<ref name="Bowler325-339">{{wikiref|id=Bowler-2003|text=Bowler 2003 pp. 325–339}}</ref><ref name="Larson221-243">{{wikiref|id=Larson-2004|text=Larson 2004 pp. 221–243}}</ref> The American biologist [[Sewall Wright]], who had a background in animal breeding experiments, focused on combinations of interacting genes, and the effects of inbreeding on small, relatively isolated populations that exhibited [[genetic drift]]. In 1932, Wright introduced the concept of an [[adaptive landscape]] and argued that genetic drift and inbreeding could drive a small, isolated sub-population away from an adaptive peak, allowing natural selection to drive it towards different adaptive peaks. The work of Fisher, Haldane and Wright founded the discipline of [[population genetics]], which integrated natural selection with Mendelian genetics.<ref name="Bowler325-339"/><ref name="Larson221-243"/> ===Modern evolutionary synthesis=== In the first few decades of the 20th century, most field naturalists continued to believe that Lamarckian and orthogenic mechanisms of evolution provided the best explanation for the complexity they observed in the living world. However, as the field of genetics continued to develop, those views became less tenable.<ref>{{wikiref|id=Mayr-1998|text= Mayr and Provine (1998) pp. 295–298, 416}}</ref> [[Theodosius Dobzhansky]], a postdoctoral worker in T. H. Morgan's lab, had been influenced by the work on genetic diversity done by [[Russia]]n geneticists such as [[Sergei Chetverikov]]. He would help to bridge the divide between the population geneticists and the field biologists with his 1937 book ''[[Genetics and the Origin of Species]]''. Dobzhansky examined the genetic diversity of wild populations and showed that, contrary to the assumptions of the population geneticists, these populations had large amounts of genetic diversity, with marked differences between sub-populations. The book also took the highly mathematical work of the population geneticists and put it into a more accessible form.<ref name="Bowler325-339"/><ref name="Larson221-243"/> [[Ernst Mayr]] was influenced by the work of the German biologist [[Bernhard Rensch]] on how local environmental factors influenced the geographic distribution of sub-species and closely related species. Mayr followed up on Dobzhansky's work with the 1942 book ''Systematics and the Origin of Species'', which emphasized the importance of [[allopatric speciation]] in the formation of new species. This form of speciation occurs when the geographical isolation of a sub-population is followed by the development of mechanisms for [[reproductive isolation]]. Mayr also formulated the [[biological species concept]] that defined a species as a group of interbreeding or potentially interbreeding populations that were reproductively isolated from all other populations.<ref name="Bowler325-339"/><ref name="Larson221-243"/><ref>{{wikiref|id=Mayr-1998|text= Mayr and Provine (1998) pp. 33–34}}</ref> In the 1944 book ''Mode and Tempo in Evolution'', [[George Gaylord Simpson]] showed that the fossil record was consistent with the irregular non-directional pattern predicted by the developing evolutionary synthesis, and that the linear trends that earlier paleontologists had claimed supported orthogenesis and neo-Lamarckism did not hold up to closer examination. In 1950, [[G. Ledyard Stebbins]] published ''[[Variation and Evolution in Plants]]'', which helped to integrate [[botany]] into the synthesis. The emerging cross-disciplinary consensus on the workings of evolution would be known as the [[modern evolutionary synthesis]]. It received its name from the book ''Evolution: the modern synthesis'' by [[Julian Huxley]].<ref name="Bowler325-339"/><ref name="Larson221-243"/> ==1940s–1960s: Molecular biology== {{main|History of molecular evolution}} In the 1940s, following up on [[Griffith's experiment]] on [[transformation (genetics)|bacterial transformation]], [[Oswald Avery|Avery]], [[Colin MacLeod|MacLeod]] and [[Maclyn McCarty|McCarty]] definitively identified [[DNA|deoxyribonucleic acid (DNA)]] as the [[transforming principle]] responsible for transmitting genetic information.<ref>{{cite journal |author=Avery O, MacLeod C, McCarty M |title=Studies on the chemical nature of the substance inducing transformation of pneumococcal types. Inductions of transformation by a desoxyribonucleic acid fraction isolated from pneumococcus type III | url=http://www.jem.org/cgi/reprint/149/2/297 | journal=J Exp Med |volume=79 |issue=2 | pages=137&ndash;158 |year=1944 |doi=10.1084/jem.79.2.137}}</ref> In 1953, [[Francis Crick]] and [[James D. Watson]] published their famous paper on the structure of DNA, based on the research of [[Rosalind Franklin]] and [[Maurice Wilkins]].<ref name=FWPUB>Watson J.D. and Crick F.H.C. [http://www.nature.com/nature/dna50/watsoncrick.pdf "A Structure for Deoxyribose Nucleic Acid".] (PDF) ''Nature'' 171, 737&ndash;738 (1953). Accessed 13 Feb 2007.</ref> These developments ignited the era of [[molecular biology]] and led to the understanding of evolution as a molecular process: the mutation of segments of DNA. During this era of [[molecular biology]], it became clear that a major mechanism causing variation within a population was DNA [[mutagenesis|mutation]]. In the mid-1970s, [[Motoo Kimura]] formulated the [[neutral theory of molecular evolution]], establishing the importance of [[genetic drift]] as a major mechanism of evolution.<ref>{{cite journal |author=Kimura M |title=Preponderance of synonymous changes as evidence for the neutral theory of molecular evolution |journal=Nature |volume=267 |issue=5608 |pages=275–6 |year=1977 |pmid=865622 |doi=10.1038/267275a0}}</ref> The theory sparked the "neutralist–selectionist" debate, partially solved by the development of [[Tomoko Ohta]]'s [[nearly neutral theory of evolution]].<ref>{{Cite journal| doi = 10.1038/246096a0| volume = 246| issue = 5428| pages = 96–98| last = Ohta| first = Tomoko| title = Slightly Deleterious Mutant Substitutions in Evolution| journal = Nature| date = 1973-11-09}}</ref> ==Since the 1960s== ===Gene-centered view of evolution=== In the mid-1960s, [[George C. Williams]] strongly critiqued explanations of adaptations couched in terms of "survival of the species" (essentially [[group selection]] arguments). Such explanations were largely replaced by a [[gene-centered view of evolution]], epitomized by the [[kin selection]] arguments of [[W. D. Hamilton]], [[George R. Price]] and [[John Maynard Smith]].<ref>{{cite journal |author=Mayr E |title=The objects of selection |url=http://www.pnas.org/cgi/content/full/94/6/2091 |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=94 |issue=6 |pages=2091&ndash;94 |year=1997 |pmid=9122151 |doi=10.1073/pnas.94.6.2091}}</ref> This viewpoint would be summarized and popularized in the influential 1976 book ''[[The Selfish Gene]]'' by [[Richard Dawkins]].<ref>{{wikiref|id=Bowler-2003|text= Bowler 2003 p. 361}}</ref> Models of the period showed that [[group selection]] was severely limited in its strength, although these models have since been shown to be too limited and newer models do admit the possibility of significant multi-level selection.<ref name=Gould>{{cite journal |author=Gould SJ |title=Gulliver's further travels: the necessity and difficulty of a hierarchical theory of selection |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=9533127 |journal=Philos. Trans. R. Soc. Lond., B, Biol. Sci. |volume=353 |issue=1366 |pages=307&ndash;14 |year=1998 |pmid=9533127 |doi=10.1098/rstb.1998.0211}}</ref> In 1973, [[Leigh Van Valen]] proposed the term "[[Red Queen]]", which he took from ''[[Through the Looking Glass]]'' by [[Lewis Carroll]], to describe a scenario where a species involved in one or more [[evolutionary arms race]]s would have to constantly change just to keep pace with the species with which it was [[co-evolving]]. Hamilton, Williams and others suggested that this idea might help explain the [[evolution of sexual reproduction]], because the increased genetic diversity caused by sexual reproduction would help maintain resistance against rapidly evolving parasites. They felt this might explain why sexual reproduction was so common despite the tremendous cost from the gene-centric point of view of a system where only half of an organism's [[genome]] is passed on during reproduction.<ref>{{wikiref|id=Larson 2004|text= Larson 2004 p. 279}}</ref><ref>{{wikiref|id=Bowler-2003|text= Bowler 2003 p. 358}}</ref> The gene-centric view has also led to an increased interest in Darwin's old idea of [[sexual selection]],<ref>{{wikiref|id=Bowler-2003|text= Bowler 2003 pp. 358–359}}</ref> and more recently in topics such as [[sexual conflict]] and [[intragenomic conflict]]. ===Sociobiology=== W. D. Hamilton's work on kin selection also contributed to the emergence of the discipline of [[sociobiology]]. The existence of [[Altruism|altruistic behaviors]] has been a difficult problem for evolutionary theorists from the beginning.<ref>{{cite journal |author=Sachs J |title=Cooperation within and among species |journal=J. Evol. Biol. |volume=19 |issue=5 |pages=1415–8; discussion 1426–36 |year=2006 |pmid=16910971 |doi=10.1111/j.1420-9101.2006.01152.x}}</ref> Significant progress was made in 1964 when Hamilton formulated the inequality known as [[Hamilton's rule]], which showed how [[eusociality]] in insects (the existence of sterile worker classes) and many other examples of altruistic behavior could have evolved through kin selection. Other theories followed, some derived from [[game theory]], such as [[reciprocal altruism]].<ref>{{cite journal |author=Nowak M |title=Five rules for the evolution of cooperation |journal=Science |volume=314 |issue=5805 |pages=1560–63 |year=2006 |pmid=17158317 |doi=10.1126/science.1133755}}</ref> In 1975, [[E.O. Wilson]] published the influential and highly controversial book ''[[Sociobiology: The New Synthesis]]'' which claimed evolutionary theory could help explain many aspects of animal, including human, behavior. Critics of sociobiology, including [[Stephen Jay Gould]] and [[Richard Lewontin]], claimed that sociobiology greatly overstated the degree to which complex human behaviors could be determined by genetic factors. They also claimed that the theories of sociobiologists often reflected their own ideological biases. Despite these criticisms, work has continued in sociobiology and the related discipline of [[evolutionary psychology]], including work on other aspects of the altruism problem.<ref>{{wikiref|id=Larson-2004|text=Larson 2004 pp. 270–278}}</ref><ref>{{wikiref|id=Bowler-2003|text=Bowler 2003 pp. 359–361}}</ref> [[Image:Collapsed tree labels simplified.png|right|thumb|250px|[[Phylogenetic tree]] showing the [[Domain (biology)|three-domain system]]. [[Eukaryote]]s are colored red, [[Archaea]] green, and [[Bacteria]] blue.]] ===Evolutionary paths and processes=== One of the most prominent debates arising during the 1970s was over the theory of [[punctuated equilibrium]]. It was proposed by [[Niles Eldredge]] and [[Stephen Jay Gould]] who said there was a pattern of fossil species remaining largely unchanged for long periods (what they termed ''stasis''), with relatively brief periods of rapid change during speciation.<ref name=pe1972>Niles Eldredge and Stephen Jay Gould, 1972. [http://www.blackwellpublishing.com/ridley/classictexts/eldredge.asp "Punctuated equilibria: an alternative to phyletic gradualism"] In T.J.M. Schopf, ed., ''Models in Paleobiology''. San Francisco: Freeman Cooper. pp. 82–115. Reprinted in N. Eldredge ''Time frames''. Princeton: Princeton Univ. Press. 1985</ref><ref>{{cite journal |author=Gould SJ |title=Tempo and mode in the macroevolutionary reconstruction of Darwinism |url=http://www.pnas.org/cgi/reprint/91/15/6764 |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=91 |issue=15 |pages=6764–71 |year=1994 |pmid=8041695 |doi=10.1073/pnas.91.15.6764}}</ref> Improvements in [[sequencing]] methods resulted in a large increase of sequenced [[genome]]s, allowing the testing and refining of evolutionary theories using this huge amount of genome data.<ref>{{cite journal |author=Pollock DD, Eisen JA, Doggett NA, Cummings MP |title=A case for evolutionary genomics and the comprehensive examination of sequence biodiversity |journal=Mol. Biol. Evol. |volume=17 |issue=12 |pages=1776–88 |year=2000 |pmid=11110893 |url=http://mbe.oxfordjournals.org/cgi/content/full/17/12/1776}}</ref> This research is providing insights into the molecular mechanisms of speciation and adaptation.<ref>{{cite journal |author=Koonin EV |title=Orthologs, paralogs, and evolutionary genomics |journal=Annu. Rev. Genet. |volume=39 |issue= |pages=309–38 |year=2005 |pmid=16285863 |doi=10.1146/annurev.genet.39.073003.114725}}</ref><ref>{{cite journal |author=Hegarty MJ, Hiscock SJ |title=Hybrid speciation in plants: new insights from molecular studies |journal=New Phytol. |volume=165 |issue=2 |pages=411–23 |year=2005 |pmid=15720652 |doi=10.1111/j.1469-8137.2004.01253.x}}</ref> Such genomic analysis has produced fundamental changes, such as the [[three-domain system]] of [[Carl Woese]], in our understanding of the [[evolutionary history of life]].<ref name=Woese>{{cite journal |author=Woese C, Kandler O, Wheelis M |title=Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya | url=http://www.pnas.org/cgi/reprint/87/12/4576 |journal=Proc Natl Acad Sci U S A |volume=87 |issue=12 |pages=4576–79 |year=1990 |pmid=2112744 |doi=10.1073/pnas.87.12.4576}}</ref> Advances in computational hardware and software have allowed for the testing and extrapolation of increasingly advanced evolutionary [[Model (abstract)|models]] and the development of the field of [[systems biology]].<ref>{{cite journal |author=Medina M |title=Genomes, phylogeny, and evolutionary systems biology |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=102 Suppl 1 |issue= |pages=6630–5 |year=2005 |pmid=15851668 |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=15851668 |doi=10.1073/pnas.0501984102}}</ref> One of the results has been an exchange of ideas between theories of biological evolution and the field of [[computer science]] known as [[evolutionary computation]], which uses processes that attempt to mimic biological evolution in the development of new computer [[algorithms]]. Discoveries in [[biotechnology]] are now producing methods for the synthesis and modification of entire genomes, driving evolutionary studies to the level where future experiments may involve the creation of entirely synthetic organisms.<ref>{{cite journal |author=Benner SA, Sismour AM |title=Synthetic biology |journal=Nat. Rev. Genet. |volume=6 |issue=7 |pages=533–43 |year=2005 |pmid=15995697 |doi=10.1038/nrg1637}}</ref> ===Microbiology and horizontal gene transfer=== {{main|Horizontal gene transfer}} [[Microbiology]] has just recently developed into an evolutionary discipline. It was originally ignored due to the paucity of morphological traits and the lack of a species concept in microbiology, particularly amongst [[prokaryote]]s.<ref>{{cite journal |author=Gevers D, Cohan FM, Lawrence JG, ''et al'' |title=Opinion: Re-evaluating prokaryotic species |journal=Nat. Rev. Microbiol. |volume=3 |issue=9 |pages=733–9 |year=2005 |pmid=16138101 |doi=10.1038/nrmicro1236}}</ref> Now, evolutionary researchers are taking advantage their improved understanding of microbial physiology and ecology, produced by the comparative ease of microbial [[genomics]], to explore the taxonomy and evolution of these organisms.<ref>{{cite journal |author=Coenye T, Gevers D, Van de Peer Y, Vandamme P, Swings J |title=Towards a prokaryotic genomic taxonomy |journal=FEMS Microbiol. Rev. |volume=29 |issue=2 |pages=147–67 |year=2005 |pmid=15808739 |doi=10.1016/j.femsre.2004.11.004}}</ref> These studies are revealing completely unanticipated levels of diversity amongst microbes, demonstrating that these organisms are the dominant form of life on Earth.<ref>{{cite journal |author=Whitman W, Coleman D, Wiebe W |title=Prokaryotes: the unseen majority |url=http://www.pnas.org/cgi/content/full/95/12/6578 |journal=Proc Natl Acad Sci U S A |volume=95 |issue=12 |pages=6578–83 |year=1998|pmid=9618454 |doi=10.1073/pnas.95.12.6578}}</ref><ref name=Schloss>{{cite journal |author=Schloss P, Handelsman J |title=Status of the microbial census |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=15590780#r6 |journal=Microbiol Mol Biol Rev |volume=68 |issue=4 |pages=686–91 |year=2004 |pmid=15590780 |doi=10.1128/MMBR.68.4.686-691.2004}}</ref> One particularly important outcome from studies on microbial evolution was the discovery in Japan of [[horizontal gene transfer]] in 1959.<ref>{{cite journal |author=Ochiai K, Yamanaka T, Kimura K Sawada O |title=Inheritance of drug resistance (and its transfer) between Shigella strains and Between Shigella and E.coli strains |journal=Hihon Iji Shimpor |volume=1861 |pages=34 |year=1959}} (in Japanese)</ref> This transfer of genetic material between different species of bacteria has played a major role in the propagation of [[antibiotic resistance]].<ref>{{cite web|title=Lateral gene transfer and the nature of bacterial innovation|url=http://www.stat.rice.edu/~mathbio/Ochman2000.pdf|publisher=Nature Vol 405, May 18 2000|accessdate=2007-09-01}}</ref> More recently, as knowledge of [[genome]]s has continued to expand, it has been suggested that lateral transfer of genetic material has played an important role in the evolution of all organisms.<ref>{{cite journal |author=de la Cruz F, Davies J |title=Horizontal gene transfer and the origin of species: lessons from bacteria |journal=Trends Microbiol. |volume=8 |issue=3 |pages=128–33 |year=2000 |pmid=10707066 |doi=10.1016/S0966-842X(00)01703-0}}</ref> Indeed, as part of the [[endosymbiotic theory]] for the origin of [[organelle]]s, horizontal gene transfer has been a critical step in the evolution of eukaryotes such as fungi, plants, and animals.<ref>{{cite journal |author=Poole A, Penny D |title=Evaluating hypotheses for the origin of eukaryotes |journal=Bioessays |volume=29 |issue=1 |pages=74–84 |year=2007 |pmid=17187354 |doi=10.1002/bies.20516}}</ref><ref name=Dyall>{{cite journal |author=Dyall S, Brown M, Johnson P |title=Ancient invasions: from endosymbionts to organelles |journal=Science |volume=304 |issue=5668 |pages=253&ndash;7 |year=2004 |pmid=15073369 |doi=10.1126/science.1094884}}</ref> ===Evo-devo=== {{main|Evolutionary developmental biology}} In the 1980s and 1990s the tenets of the [[modern evolutionary synthesis]] came under increasing scrutiny. There was a renewal of [[structuralism|structuralist]] themes in evolutionary biology in the work of biologists such as [[Brian Goodwin]] and [[Stuart Kauffman]], which incorporated ideas from [[cybernetics]] and [[systems theory]], and emphasized the [[self-organization|self-organizing]] processes of development as factors directing the course of evolution. The evolutionary biologist [[Stephen Jay Gould]] revived earlier ideas of [[heterochrony]], alterations in the relative rates of developmental processes over the course of evolution, to account for the generation of novel forms, and, with the evolutionary biologist [[Richard Lewontin]], wrote an influential paper in 1979 suggesting that a change in one biological structure could arise incidentally as an accidental result of selection on another structure, rather than through direct selection for that particular adaptation. They called this [[exaptation]].<ref>{{cite journal |author=Gould SJ |title=The exaptive excellence of spandrels as a term and prototype |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=94 |issue=20 |pages=10750–5 |year=1997 |pmid=11038582 |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=11038582 |doi=10.1073/pnas.94.20.10750}}</ref> Molecular data regarding the mechanisms underlying [[developmental biology|development]] accumulated rapidly during the 1980s and '90s. It became clear that the diversity of animal morphology was not the result of different sets of proteins regulating the development of different animals, but from changes in the deployment of a small set of proteins that were common to all animals.<ref>{{cite journal |author=True JR, Carroll SB |title=Gene co-option in physiological and morphological evolution |journal=Annu. Rev. Cell Dev. Biol. |volume=18 |issue= |pages=53–80 |year=2002 |pmid=12142278 |doi=10.1146/annurev.cellbio.18.020402.140619}}</ref> These proteins became known as the [[Evolutionary developmental biology#The developmental-genetic toolkit|"developmental toolkit"]].<ref>{{cite journal |author=Cañestro C, Yokoi H, Postlethwait JH |title=Evolutionary developmental biology and genomics |journal=Nat Rev Genet |volume=8 |issue=12 |pages=932–942 |year=2007 |pmid=18007650 |doi=10.1038/nrg2226}}</ref> Such perspectives influenced the disciplines of [[phylogenetics]], [[paleontology]] and comparative developmental biology, and spawned the new discipline of "evo-devo."<ref>{{cite journal |author=Baguñà J, Garcia-Fernàndez J |title=Evo-Devo: the long and winding road |url=http://www.ijdb.ehu.es/web/paper.php?doi=14756346 |journal=Int. J. Dev. Biol. |volume=47 |issue=7–8 |pages=705–13 |year=2003 |pmid=14756346}}<br />*{{cite journal |author=Gilbert SF |title=The morphogenesis of evolutionary developmental biology |journal=Int. J. Dev. Biol. |volume=47 |issue=7–8 |pages=467–77 |year=2003 |pmid=14756322}}</ref> More recent work in this field has emphasized [[phenotypic plasticity|phenotypic and developmental plasticity]]. It has been suggested, for example, that the rapid emergence of basic animal body plans in the [[Cambrian Explosion]] was due in part to changes in the environment acting on inherent material properties of cell aggregates, such as differential cell adhesion and biochemical oscillation. The resulting forms were later stabilized by natural selection.<ref>{{cite journal |author=Newman SA, Müller GB |title=Epigenetic mechanisms of character origination |journal=J. Exp. Zool. B Mol. Develop. Evol. |volume=288 |pages=304–17 |year=2000 |pmid=11144279 |doi=10.1002/1097-010X(20001215)288:4<304::AID-JEZ3>3.0.CO;2-G}}</ref> Experimental and theoretical research on these and related ideas has been presented in the multi-authored volume [[Origination of Organismal Form]]. ==Unconventional evolutionary thought== ===Gaia hypothesis=== {{main|Gaia hypothesis}} [[Pierre Teilhard de Chardin]] formulated theories describing the gradual development of the Universe from subatomic particles to human society, considered by Teilhard as the last stage (see [[Gaia theory]]), but his ideas were not accepted by the scientific community. However, this hypothesis was later developed in a more limited and rigorous form by [[James Lovelock]], who proposed that the living and nonliving parts of Earth can be viewed as a complex interacting system with similarity to a single organism.<ref>{{cite journal |author=Lovelock J |title=Gaia: the living Earth |journal=Nature |volume=426 |issue=6968 |pages=769–70 |year=2003 |pmid=14685210 |doi=10.1038/426769a}}</ref> This modified hypothesis postulates that all living things have a regulatory effect on the Earth's environment that promotes life overall. Although not fully accepted by the scientific community, this hypothesis has been a useful spur to further research and is a topic of current scientific debate.<ref>{{cite journal |author=Free A, Barton NH |title=Do evolution and ecology need the Gaia hypothesis? |journal=Trends Ecol Evol |volume= |issue= |pages= |year=2007 |pmid=17954000 |doi=10.1016/j.tree.2007.07.007}}</ref><ref>{{cite journal |author=Lenton TM |title=Gaia and natural selection |journal=Nature |volume=394 |issue=6692 |pages=439–47 |year=1998 |pmid=9697767 |doi=10.1038/28792}}</ref> ==See also== * [[The Voyage of the Beagle]] * [[Galápagos Islands]] * [[Faith and rationality]] ==Notes== {{reflist|2}} ==References== * {{cite book|last=Bowler|first=Peter J.|authorlink=Peter J. Bowler|title=Evolution:The History of an Idea|publisher=University of California Press|year=2003|isbn=0-52023693-9}} * {{cite book|last=Bowler|first=Peter J.|coauthors=Iwan Rhys Morus|title=Making Modern Science|publisher=The University of Chicago Press|year=2005|isbn=0-226-06861-7}} * {{cite book|last=Darlington|first=Cyril|authorlink=Cyril Darlington|title=''Darwin's place in history''|publisher=Blackwell, Oxford, p85|year=1959}} * {{cite book|last=Darwin|first=Charles|authorlink=Charles Darwin|title=[[On the Origin of Species]] by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life|edition=1st|publisher=John Murray, London|year=1859}} * {{cite book|last=Darwin|first=Charles|authorlink=Charles Darwin|title=[[On the Origin of Species]] by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life|edition=3rd|publisher=John Murray, London|year=1861}} * {{cite book|last=Darwin|first=Charles|authorlink=Charles Darwin|title=[[On the Origin of Species]] by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life|edition=3rd|publisher=John Murray, London|year=1866}} * {{cite book|last=Darwin|first=Charles|authorlink=Charles Darwin|title=[[On the Origin of Species]] by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life|edition=6th|publisher=John Murray, London|year=1872}} *{{cite book|last=Darwin|first=Erasmus|authorlink=Erasmus Darwin|year=1825|title=''The Temple of Nature, or The Origin of Society''|url=http://books.google.com/books?id=oAl9y-0FSJQC&dq=Erasmus+Darwin+Temple}} *{{cite book|last=Darwin|first=Erasmus|year=1818|title=''Zoonomia''|url=http://www.gutenberg.org/files/15707/15707-h/15707-h.htm}} *{{cite book|last=Desmond|first=Adrian|coauthors=James Moore|title=Darwin: The Life of a Tormented Evolutionist |publisher=W. W. Norton & Company|year=1994|isbn=0393311503}} *{{cite book|last=Draper|first=John William|authorlink=John William Draper|year=1878|title=''History of the Conflict Between Religion and Science''|url=http://books.google.com/books?id=0XolqaWimmkC&dq=John+William+Draper}} *{{cite book|last=Gould|first=Stephen Jay|authorlink=Stephen Jay Gould|title=''The Structure of Evolutionary Theory''|publisher=Belknap Press of Harvard University Press|year=2002|isbn=0-674-00613-5}} *{{cite book|last=Henderson|first=Jan-Andrew|title=''The Emperor's Kilt: The Two Secret Histories of Scotland''|publisher=Mainstream Publishing|year=2000}} *{{cite book|last=Larson|first=Edward J.|authorlink=Edward Larson|title=Evolution:The Remarkable History of a Scientific Theory|publisher=Modern Library|year=2004|isbn=0-679-64288-9}} *{{cite book|last=Lovejoy|first=Arthur|authorlink=Arthur Oncken Lovejoy|title=The Great Chain of Being: A Study of the History of an Idea|publisher=Harvard University Press|year=1936|isbn=0-674-36153-9}} *{{Cite book|last=Mayr|first=Ernst|authorlink=Ernst Mayr|title=The Growth of Biological Thought: Diversity, Evolution, and Inheritance|publisher=The Belknap Press of Harvard University Press|year=1982|isbn=0-674-36445-7}} *{{Cite book|last=Mayr|first=Ernst|coauthors=W. B. Provine, eds.|title=The Evolutionary Synthesis: Perspectives on the Unification of Biology|publisher=Harvard University Press|year=1998|isbn=0-674-27225-0}} *{{Cite book|last=Needham|first=Joseph|authorlink=Joseph Needham|coauthors=Colin Alistair Ronan|title=The Shorter Science and Civilisation in China: An Abridgement of Joseph Needham's Original Text, Vol. 1|publisher=Cambridge University Press|year=1995|isbn=0521292867}} *{{cite book|last=Singer|first=Charles|authorlink=Charles Singer|title=A Short History of Biology|publisher=Clarendon Press|year=1931}} ==External links== * [http://evolution.berkeley.edu/evolibrary/article/history_01 UC Berkeley's History of Evolutionary Thought] * [http://www.talkorigins.org/faqs/darwin-precursors.html Darwin's precursors and influences by John Wilkins]. Part of the [[Talk.Origins Archive]]. *[http://www.wku.edu/~smithch/index1.htm The Alfred Russel Wallace Page] {{1911}} {{History of biology}} {{Evolution}} [[Category:History of evolutionary biology|*]] [[Category:History of science]] [[Category:History of ideas]] [[de:Geschichte der Evolutionstheorie]] [[es:Historia del pensamiento evolucionista]] [[fr:Histoire de la pensée évolutionniste]] [[it:Storia del pensiero evoluzionista]] [[hu:Az evolúciós gondolkodás története]] [[nl:Geschiedenis van de evolutietheorie]] [[fi:Evoluutioteorian historia]] [[zh:演化思想史]]