lecture 02 - EVIDENCE FOR EVOLUTION Chapter 3, pp. 48-55,...

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EVIDENCE FOR EVOLUTION Chapter 3, pp. 48-55, 61-65 Darwin’s three proposals ( fundamental principles ) o Evolution is descent through modification o Descent through modification leads to hierarchical organization of diversity o Natural selection – favored genes are passed on more often, leading to change in form over time, which leads to a good fit of organisms to environment Descent with modification o Most characters of organisms are modified from pre-existing characters of their ancestors; most characters do NOT arise “de novo” o Results in hierarchical organization o Ex) climbing plants – climbing structures are modifications of structures not previously used for climbing (stems or leaves) o Character – type of organism o Character state – characteristic o Homology – different uses/modifications of the same structures from an ancestor characters have similar genetic/developmental underpinnings Ex) limb bones of tetrapods (frogs, lizards, snakes, crocodiles, birds,
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This note was uploaded on 03/31/2008 for the course BIOEE 2780 taught by Professor Geber during the Fall '07 term at Cornell University (Engineering School).

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lecture 02 - EVIDENCE FOR EVOLUTION Chapter 3, pp. 48-55,...

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