Midterm1_1 - Darwinian Revolution Evolution ideas before...

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Darwinian Revolution Evolution ideas before Darwin Evolutionary ideas Did not believe in Evolution but had relevant ideas Geologists Gradualism Catastrophism Empedocles : plans before animals Aristotle : Scala Naturae described system of hierarchical structure Hutton : geological features explained by current mechanisms Cuvier : Different fossils in different strata due to catastrophe Erasmus Darwin : Darwin’s grandfather, ideas of trasmutation, competition, sexual selection Linnaeus : Classification system Lyell : mechanisms of change constant over time Lamarck : Theory of Acquired Characters Alfred Russel Wallace : independently described evolutionary mechanism almost identical to Darwin’s ** Malthus’ Basic Theory: Population exceeds resources creating a point of crisis Darwin’s Theory of Natural Selection: Observation: 1. Members of population vary in traits 2. Traits inherited from parent to offspring 3. All species capable of producing more offspring than environment can support 4. Lack of resources prevent all offspring from surviving Inferred: 1. Individuals with higher probability of survival and reproduction pass traits on to offspring 2. Offspring with more favorable traits survive better and continue to reproduce. Post-Darwinian examples of natural selection Predation and coloration in Guppies - Pools w/ high predators = drab-colored male guppies; low predators = bright-colored guppies - Killifish eat juvenile guppies that haven’t yet displayed adult coloration  more bright-colored males (due to female  preference) Drug-Resistant HIV - 3TC molecule similar to Cytosine nucleotide; when picked up by HIV reverse transcriptase to duplicate virus  RNA genome, the error terminates further duplication of DNA and blocks HIV reproduction
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- 3TC resistant HIV have reverse transcriptase that discriminates btw 3TC and C 5 Darwin Myths: 1. Darwin first to propose evolution of life 2. Darwin went to Galapagos to study the beaks of finches and thus discovered evolution 3. Darwin’s “on the Origin of Species” documents numerous examples of natural selection a. Documents artificial selection, not natural selection 4. Evolution is a theory about the origin of life a. Organisms can be traced to a single ancestor but no idea on how life originated 5. Darwin was an atheist a. Religious views were complicated: born a Christian, later an Agnostic Case for and Against Evolution Arguments Against Evolution Evidence for Evolution 1. Evolution cannot be observed and cannot be proven 1. Evolution observed all the time - in beak size in Galapagos finches - Predators & Guppy coloration - Industrial melanism in moths - Evolution of pesticide resistance - Evolution of antibiacterial/ antiviral resistance Anatomical and Molecular homologies - Mammalian forelimbs: human arm, bat wing - Vestigial traits: historical remnants of traits important for ancestors
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This note was uploaded on 01/27/2011 for the course BISC 120 taught by Professor Webb,wetzer,? during the Fall '07 term at USC.

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Midterm1_1 - Darwinian Revolution Evolution ideas before...

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