Biology 1001A Lecture Notes - Lecture 15: Parental Investment, Coevolution, Resource Holding Potential
22 Nov 2017
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Document Summary
Sex is widespread despite being costly, risky and inefficient; because the benefits of offspring diversity often outweigh the costs. In many animals, one sex (but not the other) expresses costly traits that reduce survival: expose organism to predators, time intensive to produce. Intrasexual selection (contest: males have horns as weapons to kill other males. Intersexual selection (attraction: long tails are attractive and females mate with males with longer tails. In recording history, male with highest fitness produced 888 children. Why be choosy: direct benefits (attractive males are good dads, food, territory, protection. Indirect benefits (attractive males have good genes: offspring health and viability, sexy sons/ a taste for the beautiful (attractiveness is arbitrary, but attractive males have attractive sons) Sex differences in parental investment and potential fitness determine which sex competes and which sex chooses: red phalaropes and seahorses - females fight for males, males provide parental care, females are larger.
