BIO220H1 Chapter Notes - Chapter 15: Mate Choice, Sexual Selection, Sexual Conflict

• School: UTSG
• Department: Biology
• Course: BIO220H1
• Professor: John Stinchcombe

Document Summary

Reading article 15 sexual selection [patricia l. r. brennan] Natural selection: organisms better adapted to environment = higher survival rates. Anomaly: some apparently non-adaptive sexual traits that didn"t help survival of organism, darwin: such traits evolve under sexual selection. = trait increases individual"s reproductive success at expense of survival. Sexual selection depends on struggle btwn male to access females. 2 mechanisms of sexual selection: (1) intra-sexual selection: competition between members of same sex (males usually) for mate access (2) inter-sexual selection, members of one sex (usually females) choose members of opposite sex. Idea that cumbersome traits evolved to help male competition accepted by scientists. Sex roles defined by diffs in gametes: female gametes: Only need 1 of each type of gamete to make offspring: = excess male gametes that don"t fertilize any eggs. Female reproduction = resource limited to nourish/produce large gametes: = females are choosy and mate with preferred males.