SEXUAL SELECTION - of parental investment . Sexual...

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SEXUAL SELECTION So far all of our discussions of selection have been without much regard for the sex of the individual under selection (evolution of the sex ratio to 1:1 can occur through selection for alleles in either males or females that favor the production of the rare sex). But just as with natural selection individuals may differ in their ability to reproduce, in sexual selection there can be differential reproductive success among individuals of the same sex (and species). In order to mate, males need to gain access to females and vice versa, and not all individuals will be equally successful at this task. If there are genetically based differences in the ability of one sex to insure successful mating with the other sex, sexual selection will occur. The patterns and processes of sexual selection are best understood in the context
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Unformatted text preview: of parental investment . Sexual selection occurs because there is a correlation between the gender of an individual and its parental investment in each offspring. Parental investment is the investment of resources that increases in the probability offspring will survive (a benefit ) while decreasing the parent's ability to produce more offspring (a cost ). By investing in the production of current offspring a parent will reduce the likelihood that it will be able to invest in future offspring. Costs can be the energetic demands of parenting, increased predation risk, etc. Parental investment should be proportional to: (Benefit to current offspring survival) / (Cost to future offspring survival)...
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