Evolution Introduction https://www.youtube.com/watch?v=YgHrn2VFbvo

Varieties of life forms Figure 1.4C-F

Clown, Fool, or Well Adapted? All organisms have evolutionary adaptations Inherited characteristics that enhance their ability to survive and reproduce blue-footed booby Large, webbed feet help propel the bird through water at high speeds

Specialized salt-secreting glands manage salt intake while at sea A streamlined shape, large tail, and nostrils that close are useful for diving Specialized salt-secreting glands manage salt intake while at sea Adaptations do not create perfect orgs. Lg feet are clumsy on land. But overall, lg feet contributed more to repro success than small feet, so the boobies had large feet.

Evolution explains the unity and diversity of life Charles Darwin synthesized the Theory of Evolution by natural selection Theory vs hypothesis Evolution is the core theme of biology Who was Darwin? Biologist at age 22, taken on 5 yr voyage to explore. Europeans realized the economic potential of natural resources, wanted to “discover” and exploit them worldwide. 1859 published On the Origin of Species. Presented theory of natural selection Radical change in std western thinking. religions stated age of earth as 6K, based on Bible Aristotle held that species are fixed, unchanging Evolution theory explained lots of different observtns, simplified what appeared to be complex systems Th4, THEORY, not just sgl hypothesis. Diversity of life explained. A reason for all the types of animals, why some finches have beaks of this shape and others are different. Unifying theory – many orgs descended from a common ancestor. Wallace also conceived idea,based on observtn sent his paper to Darwin for his comments. So Darwin hurried to publish his own work and get credit.

The voyage of the Beagle Great Britain North America Europe Pacific Ocean Atlantic Ocean Africa Galápagos Islands South America Equator Cape of Good Hope Andes Australia Tierra del Fuego New Zealand Cape Horn Tasmania

Prevalent ideas at Darwin’s time species are fixed Earth is about 6,000 yrs old Evidence for evolution. Current thought, very solid in western culture: fixed species. Also, literal interp of Bible and religious bks, earth is 6K old. Fossils indicated this maybe wrong, that earth and life were much older.

New ideas proposed Fossils indicated the earth was very old Georges Cuvier: Fossils indicated the earth was very old

Lyell, a geologist, argued that land forms changed constantly. New ideas proposed Charles Lyell: Lyell, a geologist, argued that land forms changed constantly.

New ideas proposed Jean Baptiste Lamarck: Lamarck proposed that organisms changed and these changes were passed to progeny.

Darwin became convinced that the Earth was old and continually changing He concluded that living things also change, or evolve over generations He also stated that living species descended from earlier life-forms: descent with modification

Darwin proposed natural selection as the mechanism of evolution Darwin observed that: organisms produce more offspring than the environment can support organisms vary in many characteristics these variations can be inherited He concluded that living things also change, or evolve over generations He also stated that living species descended from earlier life-forms: descent with modification

Charles Darwin, 1874 Alfred Wallace Man with beard Man with longer beard

Darwin cartoon

Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the reproductive success of some individuals over others Natural selection is the editing mechanism Evolution is based on adaptations