BLG 312 Lecture Notes - Assortative Mating, Genetic Drift, Mate Choice
11 Feb 2013
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Document Summary
Natural selection is a potent force for divergence. Sexual selection acts on characters involved in mate choice. Changes in sexual selection can cause reproductive isolation and trigger rapid divergence. Sexual selection is a form of natural selection that results from differences among individuals in their ability to obtain mates. It has been shown that changes in the way that a population of sexual organisms chooses or acquires mates can lead to rapid differentiation from the ancestral populations. The key point is that sexual selection promotes divergence efficiently because it affects gene flow directly. Suppose a particular speciation event begins with the geographic isolation of two populations and a corresponding reduction in gene flow, and then continues as selection, mutation, and drift cause genetic divergence between the two groups. Due to this, there should be strong natural selection in favour of assortative mating- meaning that selection should favour individuals that choose mates only from the same population.
