Charles Darwin (1809-1882)

1650s – Archbishop James Ussher proposes the date 4004 BC for the beginning of the universe

the 10th edition of Systema Naturae (biol. classification) 1758 – Linnaeus published the 10th edition of Systema Naturae (biol. classification) 1785 – Hutton publishes The Theory of the Earth (gradualism) - the earth is shaped by geological forces that took place over very long periods of time

1809- Lamarck argues acquired characteristics are passed from parents to offspring

1) Use and Disuse: parasites and other organisms lost parts because they did not use them - like the missing eyes and digestive system of the tapeworm, or the vestigial femur of marine mammals 2) Perfection with use and need: the constant use of an organ leads that organ to increase in size, like the muscles of a blacksmith or the large ears of a night-flying bat. 3) Inheritance of Acquired Traits: an animal who altered its body structure during its lifetime would pass these traits on to its offspring: Ex: Arnold S. would pass on his physique to his kids

Lamarck’s Giraffe

1830 – Lyell publishes Principles of Geology advocating an “old” earth (Uniformitarianism) 1831 – The H.M.S. Beagle leaves England

Robt. Fitzroy HMS Beagle (1831-36) Charles Darwin (1809 – 1882)

The main mission of the five-year voyage of the Beagle was to chart poorly known stretches of the South American coastline. Fig. 22.5 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

1838 – Darwin reads Malthus’ essay on Principle of Population 1858 – Darwin receives a letter from Alfred Wallace

Then, in 1858, Darwin received a letter that changed everything….. Alfred Russel Wallace, a young naturalist working in the East Indies, had written a short paper with a novel theory. He asked Darwin to evaluate his theory and pass it along for publication.

Darwin wrote to Wallace: "Your words have come true with a vengeance Darwin wrote to Wallace: "Your words have come true with a vengeance ... I never saw a more striking coincidence ... so all my originality, whatever it may amount to, will be smashed."

22 of the 29 species of birds on the Galapagos are endemic (found only on these islands). Darwin collected specimens of each of the species. At first, he paid little note to a series of small but distinctive birds.Some of these animals seemed woodpecker- like, some warbler-like, and some finch-like.

14 Species of Darwin’s Finches bred in the early 80s 14 Species of Darwin’s Finches

“Succession of types.” Armadillos are native to the Americas, with most species found in South America. Glyptodont fossils also unique to South America. Why should extinct armadillo-like species & armadillos be found on same continent?

Many islands show distinct local variations in tortoise morphology. . . . . . . . perhaps these are the first steps in the splitting of one species into several?

Darwin made two points in The Origin of Species: Today’s organisms descended from ancestral species. (descent with modification) Natural selection provided a mechanism for evolutionary change in populations. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Descent With Modification This evolutionary tree of the elephant family is based on evidence from fossils. Descent With Modification Fig. 22.7 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Darwin’s Theory of Natural Selection (1) Variation exists in natural populations. (2) Many more offspring are born each season than can possibly survive to maturity. (3) As a result, there is a struggle for existence.

(4) Characteristics beneficial in the struggle for existence will tend to become more common in the population, changing the characteristics of a species. (5) Over time, and given a steady input of new variation into a population, these processes lead to the emergence of new species.

Artificial Selection

Where did Darwin observe the finches for which he is famous? Name two geologists who proposed that the earth is older than 6000 years. (They had a big impression on Darwin).

3) What was the real significance of the title “What Darwin Never Saw”?

The majority of events that you placed on the timeline on Fri occurred within the last _____ million years. How long was the earth in existence before life was here?

Name two key points in Darwin’s theory of natural selection. Place the following organisms in evolutionary order from first to evolve to the most recent: mammals, birds, amphibians, reptiles, fish.

Darwin had two theories: Natural Selection and Descent _________ __________. Name two major points of Darwin’s Theory of Natural Selection (p. 386 – Biology Textbook)