ANTH 203 Lecture : Part 1 Chapter 1,2,3,4
12 Apr 2012
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Document Summary
Animals and plants are adapted to their conditions. Organisms are more than just suited to their environments: they are complex machines, made up of many exquisitely constructed components or adaptations that interact to help the organism survive and reproduce. Natural selection: traits that confer advantages in survival and reproduction are retained in the population, and traits that are disadvantageous disappear. Darwin"s finches: example of how natural selection produces adaptations, they were able to directly document how darwin"s 3 postulates lead to evolutionary change. Supply of food on the island was not sufficient to feed the entire population and many finches did not survive the drought (population declined) Beak depth varied among the birds and affected the bird"s survival. Observed that birds with deeper beaks were able to process large seeds better than those with a shallow beak. During the drought the relative abundance of small seeds decreased forcing shallow beaked birds to shift to large hard seeds.
