PSY354H5 Chapter Notes - Chapter 2: Sexual Selection, Motility, Promiscuity
Document Summary
The original function of sex and its only function in many species is reproduction. The reasons why many species rely on sexual rather than asexual reporudction are disrupted. First sexual reporoduction may promote the elimination of harmful mutation. Second by mixing genes from different individuals, sexual reproduction may foster the selection of advantageous traits. Natural selection has causes gametes to diverge into male and female forms. Female gametes are large and contain nutrients, male gametes are small and motile. Natural selection also acts to keep the ratio if the sexes near equality in most species because any imbalance favours animals that have offspring of the minority sex. Sex may be determined by chromosomal mechanisms as in mammals or by the temperature at which eggs are incubated as in many reptiles. Sexual selection, driven by competition for mates, has led to different morphological and behavioural traits in males and females.
