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Unformatted text preview: ** Read Diamond article on Why is Sex Fun? ** Sex Ratios Biological payoffs (number of surviving kids you leave behind) p = probability child is feminine 1p = probability child is male p = 1/2 data (50% chance of either gender) Suppose p < 1/2 (let p = 1/3) Can this go on forever?Every woman has 6 kids (reproductive Ftness);Average number of offspring per male = 12/4 = 3Therefore the Reproductive Ftness of the male is 3 Grand kidsHow many kids does a typical woman have?2 women ==> 2x6 (from daughters) + 4x3 (from sons) = 24Mutant women ==> 3x6 (daughters) + 3x3 (sons) = 27 ; where 6 is the reproductive Ftness if p > 1/2 mutants would be thrown offDarwin s argument: Nature is randomizing, but there is some sense to it. Diamond s Article: Concealed Ovulation (Estrus)When a woman is ovulating, but it s concealedWhy do you think nature came up with concealed ovulation?...
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 Spring '09

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