ANTH 201 Lecture Notes - Lecture 5: Punctuated Equilibrium, Character Displacement, Disruptive Selection
1 Jun 2016
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Document Summary
Bsc states that species are groups that are reproductively isolated from other groups using either pre-conceptive or post-conceptive measures. Species are reproductively capable with each other, but must also be able to produce offspring that are fertile and can pass on genes. For example, a horse and a donkey can mate to make a mule, but mules are infertile. If there was no migration between the wet and dry ecosystems, natural selection would be allowed to select for the most fit beak sizes. Intermediate sizes would not exist (like the chart above) because they are unfit for both ecosystems. Otherwise, if birds from the two ecosystems were allowed to freely roam to the other ecosystem, migration would cause the beak depths to be diluted to an intermediate type. The distribution would be unimodal at the intermediate. However, the bsc is more useful in theory than in practice.
