Biology 3466B Lecture : Evolution Notes
3 Feb 2012
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Document Summary
Sexual dimorphism is the difference between males and females. Males tend to be larger and more brightly coloured. Sexual selection: definition differential reproductive success due to variation among individuals in mating success. Postulates of sexual selection: 1) phenotypic variation, 2) variation is heritable, 3) variation in mating success, 4) mating success is non-random. Sexual selection in males vs. females: the strength of sexual selection differs in males than in females. Female eggs are nutrient rich (takes more to make egg) and they provide substantial parental care (takes more time and energy, huge investment). Male sperm is cheap and they provide little parental care. There is more investment in egg than sperm. In the sex with greater parental investment, time and resources limit reproductive success. Resources, not the availability of sperm, limit it. A female s potential reproductive success will be small. In the sex with lower parental investment, mating success (number of available mates) limits reproductive success.
