Biology 1001A Lecture Notes - House Finch, Gamete, Parental Investment
4 Sep 2013
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Despite fitness costs to individual is widespread because it benefits the species by speeding up evolution. Vastly decreased risk of extinction speeds up the rate that helpful mutations are combined into the same genotype. Not sufficient to explain why sex is so widespread. Selection does not favour traits that benefit the group if it comes at the expense of individual fitness. Lottery ticket hyp sex in constant versus unpredictable environments. To reproduce sexually if the environment is changeable. If environment is not likely to change, fit female should reproduce asexually (rarely the case unstable environment) Reproducing asexually in an unstable environment is not favourable. Sexual reproduction: maximize likelihood that some offspring will survive in changing environment. * sex is favoured when your environment (natural enemies) is continually evolving. * coevolutionary arms race w/ organisms that cause disease. * greater advantage of reproducing sexually b/c parasites put negative frequency dependence on hosts. Long-term advantages removing harmful mutations and combining helpful mutations.
