2-Lecture_3

2-Lecture_3 - Lecture 3 Sexual Selection Natural selection...

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Lecture 3 – Sexual Selection Natural selection was discussed in terms of “Survival of the fittest”. Both survival and the ability to reproduce contribute to fitness. Then why does the peacock have such a huge awkward tail? Natural selection vs. Sexual selection - Natural selection fails to account for extreme, detrimental characters present in only one sex - Sexual selection favors elaborate sexual characters while natural selection opposes it - Sexual selection stimulates the propagation of genes often at the expense of survival Important concepts: Sexual dimorphism – marked morphological differences between the sexes Secondary sexual characters – characters in which the two sexes of a species differ excluding the gonads, ducts, and associated glands. Sexual selection leads to the evolution of two types of traits : Armaments – traits used for battle or dominance Ornaments – traits used towards attraction or conspicuousness Two Forms of Sexual Selection Male-male competition – intrasexual selection
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2-Lecture_3 - Lecture 3 Sexual Selection Natural selection...

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