EvolutionHistory2010

EvolutionHistory2010 - Nothing in biology makes sense...

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“Nothing in biology makes sense except in the light of evolution.” T. Dobzhansky, 1973
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• History of Evolutionary Thought • Evidence for Evolution by Natural Selection • Natural Selection What is Evolution? It comes from the Latin evolvere , “to unfold or unroll”, and now simply means “to change”. Biological (or organic) evolution is change in the properties of groups of organisms over the course of generations. The changes must be passed via genes from one generation to the next. Individuals do not evolve. Populations or species do.
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In 1859, Charles Darwin provided a mechanism. But his theory of evolution by natural selection was not widely accepted for 80 years. Why?
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Elephant skull Battle of the Cyclops (R. Harryhausen)
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Greece, 630 BC GrifFns were thought to guard gold that came from the deserts of Asia (from Adrienne Mayor 2000)
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Plato and Aristotle have little to say about these giant bones - but they are thinking about the question of species and our origins. Plato (427-347 BC) and Aristotle (384-322 BC) Both Plato and Aristotle were: Typological thinkers (essentialists) : all phenomena could be arranged into classes, each defined by its “essence”. Discontinuities are the rule. Variation is unimportant and irrelevant. All that matters is the ideal form, the type. Plato and Aristotle Variation is no more than the shadow of an object on the cave wall, my son.
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And Aristotle also felt that the living world moves toward ever increasing perfection due to an intrinsic drive. This is known as “finalism” or orthogenesis. Species do not evolve in his view but they could be arranged as rungs on a ladder of increasing value. Plato and Aristotle humans animals plants Empedocles (492-432 BC) Believed in a process akin to natural selection. Prior to the appearance of humans, nature assembled monsters from various parts (e.g. centaurs). These arose by chance and then died out because they were not viable. He argued that only the more Ft survived.
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Lucretius (99-55 BC) Author of On the Nature of Things , and one of the earliest expressions of “survival of the Fttest” in ancient literature. Everything is transformed by nature and forced into new paths. One thing dwindles … another waxes strong. In those days, many species must have died out altogether and failed to multiply. Every species that you now see. . has been preserved … by cunning, prowess or speed. Christianity embraced Aristotle’s views of the Fxity of species, the scale of nature from lowly forms to humans, and added the notion of “special creation.” Evolution of species was not allowed as that implies imperfection (a need to change).
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Changing world views: 1) Constant, unchanging world of infinite duration with no beginning and no end. (Aristotle)
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EvolutionHistory2010 - Nothing in biology makes sense...

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