Mutationism-biometrics Debate

Evolutionary thought, the recognition that species change over time and the perceived understanding of how such processes work, has roots in antiquity—in the ideas of the ancient Greeks, Romans, Chinese, Church Fathers as well as in medieval Islamic science. With the beginnings of modern biological taxonomy in the late 17th century, two opposed ideas influenced Western biological thinking: essentialism, the belief that every species has essential characteristics that are unalterable, a concept which had developed from medieval Aristotelian metaphysics, and that fit well with natural theology; and the development of the new anti-Aristotelian approach to modern science: as the Enlightenment progressed, evolutionary cosmology and the mechanical philosophy spread from the physical sciences to natural history. Naturalists began to focus on the variability of species; the emergence of palaeontology with the concept of extinction further undermined static views of nature. In the early 19th century prior to Darwinism, Jean-Baptiste Lamarck (1744–1829) proposed his theory of the transmutation of species, the first fully formed theory of evolution.

In 1858 Charles Darwin and Alfred Russel Wallace published a new evolutionary theory, explained in detail in Darwin's ''On the Origin of Species'' (1859). Darwin's theory, originally called descent with modification is known contemporarily as Darwinism or Darwinian theory. Unlike Lamarck, Darwin proposed common descent and a branching tree of life, meaning that two very different species could share a common ancestor. Darwin based his theory on the idea of natural selection: it synthesized a broad range of evidence from animal husbandry, biogeography, geology, morphology, and embryology. Debate over Darwin's work led to the rapid acceptance of the general concept of evolution, but the specific mechanism he proposed, natural selection, was not widely accepted until it was revived by developments in biology that occurred during the 1920s through the 1940s. Before that time most biologists regarded other factors as responsible for evolution. Alternatives to natural selection suggested during " the eclipse of Darwinism" (c. 1880 to 1920) included inheritance of acquired characteristics ( neo-Lamarckism), an innate drive for change (orthogenesis), and sudden large mutations ( saltationism). Mendelian genetics, a series of 19th-century experiments with pea plant variations rediscovered in 1900, was integrated with natural selection by Ronald Fisher, J. B. S. Haldane, and Sewall Wright during the 1910s to 1930s, and resulted in the founding of the new discipline of population genetics. During the 1930s and 1940s population genetics became integrated with other biological fields, resulting in a widely applicable theory of evolution that encompassed much of biology—the modern synthesis.

Following the establishment of evolutionary biology, studies of mutation and genetic diversity in natural populations, combined with biogeography and systematics, led to sophisticated mathematical and causal models of evolution. Palaeontology and comparative anatomy allowed more detailed reconstructions of the evolutionary history of life. After the rise of molecular genetics in the 1950s, the field of molecular evolution developed, based on protein sequences and immunological tests, and later incorporating RNA and DNA studies. The gene-centred view of evolution rose to prominence in the 1960s, followed by the neutral theory of molecular evolution, sparking debates over adaptationism, the unit of selection, and the relative importance of genetic drift versus natural selection as causes of evolution. In the late 20th-century, DNA sequencing led to molecular phylogenetics and the reorganization of the tree of life into the three-domain system by Carl Woese. In addition, the newly recognized factors of symbiogenesis and horizontal gene transfer introduced yet more complexity into evolutionary theory. Discoveries in evolutionary biology have made a significant impact not just within the traditional branches of biology, but also in other academic disciplines (for example: anthropology and psychology) and on society at large. and

Antiquity

Greeks

Proposals that one type of animal, even humans, could descend from other types of animals, are known to go back to the first pre-Socratic Greek philosophers. Anaximander of Miletus (c. 610—546 BC) proposed that the first animals lived in water, during a wet phase of the Earth's past, and that the first land-dwelling ancestors of mankind must have been born in water, and only spent part of their life on land. He also argued that the first human of the form known today must have been the child of a different type of animal (probably a fish), because man needs prolonged nursing to live. In the late nineteenth century, Anaximander was hailed as the "first Darwinist", but this characterization is no longer commonly agreed. Anaximander's hypothesis could be considered "evolution" in a sense, although not a Darwinian one.

Empedocles (c. 490—430 BC), argued that what we call birth and death in animals are just the mingling and separations of elements which cause the countless "tribes of mortal things." Specifically, the first animals and plants were like disjointed parts of the ones we see today, some of which survived by joining in different combinations, and then intermixing during the development of the embryo, and where "everything turned out as it would have if it were on purpose, there the creatures survived, being accidentally compounded in a suitable way." Other philosophers who became more influential at that time, including Plato (c. 428/427—348/347 BC), Aristotle (384—322 BC), and members of the Stoic school of philosophy, believed that the types of all things, not only living things, were fixed by divine design.

Plato was called by biologist Ernst Mayr "the great antihero of evolutionism," because he promoted belief in essentialism, which is also referred to as the theory of Forms. This theory holds that each natural type of object in the observed world is an imperfect manifestation of the ideal, form or "species" which defines that type. In his ''Timaeus'' for example, Plato has a character tell a story that the Demiurge created the cosmos and everything in it because, being good, and hence, "... free from jealousy, He desired that all things should be as like Himself as they could be." The creator 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 " principle of plenitude"—the idea that all potential forms of life are essential to a perfect creation—greatly influenced Christian thought. However some historians of science have questioned how much influence Plato's essentialism had on natural philosophy by stating that many philosophers after Plato believed that species might be capable of transformation and that the idea that biologic species were fixed and possessed unchangeable essential characteristics did not become important until the beginning of biological taxonomy in the 17th and 18th centuries.

Aristotle, the most influential of the Greek philosophers in Europe, was a student of Plato and is also the earliest natural historian whose work has been preserved in any real detail. His writings on biology resulted from his research into natural history on and around the island of Lesbos, and have survived in the form of four books, usually known by their Latin names, '' De anima'' (''On the Soul''), '' Historia animalium'' (''History of Animals''), ''De generatione animalium'' (''Generation of Animals''), and '' De partibus animalium'' (''On the Parts of Animals''). Aristotle's works contain accurate observations, fitted into his own theories of the body's mechanisms. However, for Charles Singer, "Nothing is more remarkable than ristotle'sefforts to xhibitthe relationships of living things as a ''scala naturae''." This ''scala naturae'', described in ''Historia animalium'', classified organisms in relation to a hierarchical but static "Ladder of Life" or "great chain of being," placing them according to their complexity of structure and function, with organisms that showed greater vitality and ability to move described as "higher organisms." Aristotle believed that features of living organisms showed clearly that they had what he called a final cause, that is to say that their form suited their function. He explicitly rejected the view of Empedocles that living creatures might have originated by chance.

Other Greek philosophers, such as Zeno of Citium (334—262 BC) the founder of the Stoic school of philosophy, agreed with Aristotle and other earlier philosophers that nature showed clear evidence of being designed for a purpose; this view is known as teleology. The Roman Skeptic philosopher Cicero (106—43 BC) wrote that Zeno was known to have held the view, central to Stoic physics, that nature is primarily "directed and concentrated...to secure for the world...the structure best fitted for survival."

Chinese

Ancient Chinese thinkers such as Zhuang Zhou (c. 369—286 BC), a Taoist philosopher, expressed ideas on changing biological species. According to Joseph Needham, Taoism explicitly denies the fixity of biological species and Taoist philosophers speculated that species had developed differing attributes in response to differing environments. Taoism regards humans, nature and the heavens as existing in a state of "constant transformation" known as the ''Tao'', in contrast with the more static view of nature typical of Western thought.

Roman Empire

Lucretius' poem ''De rerum natura'' provides the best surviving explanation of the ideas of the Greek Epicurean philosophers. It describes the development of the cosmos, the Earth, living things, and human society through purely naturalistic mechanisms, without any reference to supernatural involvement. ''De rerum natura'' would influence the cosmological and evolutionary speculations of philosophers and scientists during and after the Renaissance. This view was in strong contrast with the views of Roman philosophers of the Stoic school such as Seneca the Younger (c. 4 BC – AD 65), and Pliny the Elder (23—79 AD) who had a strongly teleological view of the natural world that influenced Christian theology. Cicero reports that the peripatetic and Stoic view of nature as an agency concerned most basically with producing life "best fitted for survival" was taken for granted among the Hellenistic elite.

Early Church Fathers

Origen of Alexandria

In line with earlier Greek thought, the third-century Christian philosopher and Church Father Origen of Alexandria argued that the creation story in the Book of Genesis should be interpreted as an allegory for the falling of human souls away from the glory of the divine, and not as a literal, historical account:

Gregory of Nyssa

Gregory of Nyssa wrote:

Scripture informs us that the Deity proceeded by a sort of graduated and ordered advance to the creation of man. After the foundations of the universe were laid, as the history records, man did not appear on the earth at once, but the creation of the brutes preceded him, and the plants preceded them. Thereby Scripture shows that the vital forces blended with the world of matter according to a gradation; first it infused itself into insensate nature; and in continuation of this advanced into the sentient world; and then ascended to intelligent and rational beings (emphasis added).

Henry Fairfield Osborn wrote in his work on the history of evolutionary thought, ''From the Greeks to Darwin'' (1894):

Among the Christian Fathers the movement towards a partly naturalistic interpretation of the order of Creation was made by Gregory of Nyssa in the fourth century, and was completed by Augustine in the fourth and fifth centuries. ... regory of Nyssataught that Creation was potential. God imparted to matter its fundamental properties and laws. The objects and completed forms of the Universe developed gradually out of chaotic material.

Augustine of Hippo

In the fourth century AD, the bishop and theologian Augustine of Hippo followed Origen in arguing that the Genesis creation story should be read allegorically. In his book ''De Genesi ad Litteram'' (''On the Literal Meaning of Genesis'') he prefaces saying,

In all sacred books, we should consider the eternal truths that are taught, the facts that are narrated, the future events that are predicted, and the precepts or counsels that are given. In the case of a narrative of events, the question arises whether everything must be taken according to the figurative sense only, or whether it must be expounded and defended also as a faithful record of what happened. No Christian would dare say that the narrative must not be taken in a figurative sense. For St. Paul says: ''Now all these things that happened to them were symbolic.'' Cor 10:11And he explains the statement in Genesis, ''And they shall be two in one flesh'', as a great mystery in reference to Christ and to the Church. ph 5:32ref name=":1" />

Later he differentiates between the days of the Genesis 1 creation narrative and 24 hour days

But at least we know he days of creationare different from the ordinary day of which we are familiar

He also talks about a form of theistic evolution

The things odhad potentially created... ame
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