BIOB51H3 Lecture Notes - Sexual Selection, Mate Choice, Parental Investment
14 Dec 2012
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Lecture21 sexual selection: darwin"s dilemma: sexual dimorphism, differential parental investment, types of sexual selection, intrasexual (competition, intersexual (mate choice, definitive test: sex role reversal. Sexual dimorphism: difference in the form and behaviour of males and females of one species. Eg: frigate bird difference in anatomy, behaviour, and color. Eg: american toads males sing and amourousness. 4 types of sexual dimorphism: sexual dichromatism- difference in colour, structural dimorphism eg: horns, sexual size dimorphism, behavioural dimorphism difference in who chooses and who is persuading. Darwins dilemma: he proposed natural selection as mainly, differences in reproductive success that arise from adaptation to the environment. So why are males and females so different in many species. And, why do many of the dimorphic traits reduce survival very energetically expensive (eg the mule deer rack) and increase predation risk. Darwin: these differences are accounting for the differences in investment females invest more than males do.
