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What is gradualism and punctuated evolution? Agenda for Monday Nov 15 th 1.Finish Fossil Lab 2.Theories of Evolution Notes: Lamarck 1.Lamarck’s Giraffes
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Theories of Evolution Evolution – change in the inherited traits of a population of organisms over time 2 Main contributors – Lamarck and Darwin
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Jean Baptiste de Lamarck Proposed similar species descended from a common ancestor Living species were descended from similar extinct species
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Lamarck Use and disuse of organs – developing/changing structure and function of old organs Inheritance of acquired traits – Acquired trait – a trait that arises during the lifetime of an organism – acquired traits were passed on to the organism's offspring
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Lamarck Organisms acquire traits and then pass these traits on to their offspring
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Lamarck Right and Wrong Incorrect Not all traits acquired get passed on Important Introduced Evolution/change Realized organisms are changing
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What was Lamarck’s Theory of Evolution? Agenda for Tuesday Nov 16 th 1.Theories of Evolution: Darwin 1.Lamarck’s Giraffes 2.Darwin’s Postulates
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Darwin
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Quit Medical School and became a naturalist H.M.S. Beagle – 5 year journey to survey Wrote The Origin of Species
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Charles Lyell Wrote Principle of Geology Uniformitarianism Darwin – Habitats change slowly = requires organisms to adapt to these changes in order to survive
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Galapagos Islands Darwin landed in the Galapagos Islands and noticed differences in animal species Drew and made observations while in the Galapagos Back in England he looked at his findings – Tortoises and Finches
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Galapagos Islands Finches – collected 13 similar but separate species of finches – Each had a distinct bill (beak) Finches implied a shared recent common ancestor – Adapting to different environments Darwin reasoned over millions of years = many large differences
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Darwin’s Theory Natural selection – organisms best suited for their environment reproduce more successfully than other organisms Over several generations organisms with favorable traits increase
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Darwin’s Theories Descent with Modification Newer forms in the fossil record are modified forms of older species All species descended from one or a few original types of life
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Darwin’s Theories Modification by Natural Selection Influenced by Thomas Malthus – Populations have the potential of doubling and redoubling their numbers – Human pop. have been limited by war, disease, etc. – Darwin noted most pop. have limited growth
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Modification by Natural Selection Env’t affect individual organisms in different ways – natural selection Adaption – traits that enhance the survival and reproductive success – Resulting change in the genetic makeup of a population is evolution
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2 types of Adaptations Camouflage and mimicry
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Modification by Natural Selection An organism’s genetic contribution to the next generation is fitness – Greater fitness = better adapted to env’t = reproduces more successfully Favorable traits give organisms an adaptive advantage Environment “selects” traits – Favorable traits depend on demands of env’t
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Postulate 1 Postulate 1 – Variation within a population
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Postulate 2 Traits are inherited/passed on
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Postulate 3 More offspring are produced than can survive
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Postulate 4 Individuals with advantages traits survive
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Summary of Darwin Inherit traits Natural Selection – organisms best suited/best adapted to the environment survive and reproduce – Adaptations
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What is Natural Selection? Agenda for Wednesday Nov 17 th 1.Lamarck’s Giraffes Coloring 2.Darwin’s Postulates
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What are Darwin’s Postulates of Evolution? Agenda for Thursday Nov 18 th 1.Go over Postulates Worksheet 2.Lab 3.Rat Island Evolution
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Agenda for Friday Nov 19 th 1.Quiz 2.Galapagos Islands Video
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