LIFESCI 2D03 Chapter Notes - Chapter 12: Secondary Sex Characteristic, Isogamy, Anisogamy
6 Sep 2018
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Larger zygotes have higher viability because they contain more resources for survival: consider the fitness of small, intermediate and large-sized gametes: small gametes have a numerical advantage: they will create the most zygotes. Large gametes always produce zygotes with the highest survival. Bate(cid:373)a(cid:374)"s hypothesis a(cid:374)d pare(cid:374)tal i(cid:374)vest(cid:373)e(cid:374)t: angus bateman: examined sexual selection in fruit flies. Weapon size and mating success in dung beetles. In contest between small beetles, the large male or the male with longer horn won most contests. Fisherian runaway and good genes: darwin proposed two aspects of sexual selection theory: male-male (mate) competition, and female (mate) choice, there was no clear mechanism to explain how mate choice would derive the evolution of secondary sexual traits. In amphibians, offspring growth rate is positively related to fitness, and so the research team concluded that females do indeed select males for genetic benefits that result in higher fitness for offspring.
