That gives individuals more options to exchange genes with each other. The evidence that these fossils sexually reproduced is in the finding that the spores or reproductive cells they generated came in two forms — male and female. Indeed, cultural restraints —rather than anything anatomical—have had the biggest effect on our sexual history, Shorter says. Such virgin birthing is the norm among water fleas and rotifers. New York: Harper Perennial.
New York: Oxford University Press. The Handbook of Evolutionary Psychology. If the ones with lots of mutations die, then sex purges the species of mutations. It helps maintain positive genetic variation in a population. In the Egyptian museum, the mummified and fragile bodies of two baby girls are kept in special storage.
Thus, males and females in these species forego mating opportunities with others in order to maximize the survival of offspring they already have. Women, however, appear to lose interest in sex in monogamous partnerships. This is because the process involves choosing a sexual partner that has, itself, reached sexual maturity by making good choices. In his discussion of "the desire for sexual variety", Symons reviews literature on the " Coolidge effect ", the "phenomenon of male rearousal by a new female". To understand the real origin of sexual reproduction, though, we have to go back in time 1. She found his treatment of female sexuality both more original and more controversial than his treatment of male sexuality, and argued against his view that many aspects of female sexuality, such as the female orgasm, were only accidental by-products of evolution.
He argues that among all peoples, sex is typically understood to be a service that females render to males. Hrdy, Sarah Blaffer New York: Cornell University Press. In most species where scientists have looked for it, females mate with more males than are required for fertilization — this is true from insects to birds to primates. The more the merrier, or at least, the more options for individuals to exchange genes with each other. Shapiro considered Symons's thesis about human sexuality unprovable, and argued that by outlining the relevant theoretical and methodological issues carefully and clearly he showed the difficulties to be greater than he realized.