Charles Charles Darwin Darwin

(1809-1882)(1809-1882)

1650s – Archbishop James1650s – Archbishop JamesUssher proposes the dateUssher proposes the date4004 BC for the beginning 4004 BC for the beginning of the universeof the universe

17581758 – Linnaeus published – Linnaeus publishedthe 10the 10thth edition of Systema edition of Systema Naturae (biol. classification)Naturae (biol. classification)

17851785 – Hutton publishes – Hutton publishes The Theory of the EarthThe Theory of the Earth (gradualism) - (gradualism) - the earth is the earth is shaped by geological forces shaped by geological forces that took place over very long that took place over very long periods of timeperiods of time

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

1)1) Use and DisuseUse and Disuse: parasites and other : parasites and other organisms lost partsorganisms lost parts because they did not use them - like the missing eyes and because they did not use them - like the missing eyes and digestive system of the tapeworm, or the vestigial femur of marine digestive system of the tapeworm, or the vestigial femur of marine mammalsmammals2)2) Perfection with use and needPerfection with use and need: the constant use of an organ : the constant use of an organ leads that organ to increase in size, like the muscles of a leads that organ to increase in size, like the muscles of a blacksmith or the large ears of a night-flying bat.blacksmith or the large ears of a night-flying bat.3) 3) Inheritance of Acquired TraitsInheritance of Acquired Traits: an animal who altered its: an animal who altered itsbody structure during its lifetime would pass these traits on to 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 offspring: Ex: Arnold S. would pass on his physique to his kids

Lamarck’s GiraffeLamarck’s Giraffe

18301830 – Lyell publishes – Lyell publishes Principles ofPrinciples of Geology advocating an Geology advocating an “old” earth“old” earth(Uniformitarianism)(Uniformitarianism)

18311831 – The H.M.S. Beagle leaves – The H.M.S. Beagle leaves EnglandEngland

Charles Darwin

(1809 – 1882)

Robt.Robt. FitzroyFitzroy

HMS Beagle (1831-36)HMS Beagle (1831-36)

• The main mission of the five-year voyage of the Beagle was to chart poorly known stretches of the South American coastline.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 22.5

1838 – Darwin reads Malthus’1838 – Darwin reads Malthus’essay on Principle of essay on Principle of PopulationPopulation

1858 – Darwin receives a letter1858 – Darwin receives a letterfrom Alfred Wallacefrom Alfred Wallace

Alfred Russel Wallace, a Alfred Russel Wallace, a young naturalist working young naturalist working in the East Indies, had in the East Indies, had written a short paper with written a short paper with a novel theory. He asked a novel theory. He asked Darwin to evaluate his Darwin to evaluate his theory and pass it along for theory and pass it along for

publicationpublication..

Then, in 1858, Then, in 1858, Darwin received a Darwin received a letter that changed letter that changed everythingeverything…..…..

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

22 of the 29 species 22 of the 29 species of birds on the of birds on the Galapagos are Galapagos are endemicendemic (found only (found only on these islands).on these islands).

Darwin collected Darwin collected specimens of each of specimens of each of the species. At first, he the species. At first, he paid little note to a paid little note to a series of small but series of small but distinctive birdsdistinctive birds..Some Some of these animals of these animals seemed woodpecker-seemed woodpecker-like, some warbler-like, like, some warbler-like, and some finch-like.and some finch-like.

14 Species of 14 Species of Darwin’s FinchesDarwin’s Finches

bred in the bred in the early 80searly 80s

““Succession of types.”Succession of types.”

Armadillos are native to Armadillos are native to the Americas, with most the Americas, with most species found in South species found in South America.America.

Glyptodont fossils also Glyptodont fossils also unique to South America.unique to South America.

Why should extinct Why should extinct armadillo-like species & armadillo-like species & armadillos be found on armadillos be found on same continent?same continent?

Many islands show distinct Many islands show distinct local variations in tortoise local variations in tortoise morphology. . . .morphology. . . .

. . . . perhaps these are the . . . . perhaps these are the first steps in the splitting of first steps in the splitting of one species into several?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

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin CummingsFig. 22.7

•This evolutionary tree of the elephant family is based on evidence from fossils.

Descent WithDescent WithModificationModification

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

Darwin’s Theory of Natural SelectionDarwin’s Theory of Natural Selection

(4) Characteristics beneficial in the (4) Characteristics beneficial in the struggle for existence will tend to struggle for existence will tend to become more common in the population, become more common in the population, changing the characteristics of a species.changing the characteristics of a species.

(5) Over time, and given a steady input (5) Over time, and given a steady input of new variation into a population, these of new variation into a population, these processes lead to the emergence of new processes lead to the emergence of new species.species.

ArtificialArtificialSelectionSelection

Where did Darwin observe the Where did Darwin observe the finches for which he is famous?finches for which he is famous?

Name two geologists who Name two geologists who proposed that the earth is older thanproposed that the earth is older than6000 years. (They had a big 6000 years. (They had a big

impression on Darwin). impression on Darwin).

3) What was the real significance3) What was the real significanceof the title “What Darwin Neverof the title “What Darwin NeverSaw”?Saw”?

The majority of events that youThe majority of events that youplaced on the timeline on Friplaced on the timeline on Frioccurred within the last _____occurred within the last _____million years.million years.

How long was the earth in How long was the earth in existence before life was here?existence before life was here?

Name two key points in Darwin’s Name two key points in Darwin’s theory of natural selection.theory of natural selection.

Place the following organismsPlace the following organismsin evolutionary order fromin evolutionary order fromfirst to evolve to the most first to evolve to the most recent: mammals, birds, recent: mammals, birds, amphibians,amphibians,reptiles, fish.reptiles, fish.

Darwin had two theories:Darwin had two theories:Natural Selection and Descent Natural Selection and Descent _________ __________._________ __________.

Name two major points of Name two major points of Darwin’s Theory of Natural Darwin’s Theory of Natural Selection Selection (p. 386 – Biology Textbook) (p. 386 – Biology Textbook)