LIFESCI 2D03 Chapter Notes - Chapter 12: Polygynandry, Estrous Cycle, California Mouse
11 Jan 2017
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12. 1 sexual conflict and environmental conditions affect the evolution of mating systems. Theory of natural selection: adaptations arise due to successful survival and reproduction. Theory of sexual selection: adaptations arise due to successful mating. Intrasexual competition: mating access to the opposite sex. Sexual selection produces anatomical and behavioural differences between sexes. Females maximize survival of offspring & fathered by best available male. Males variance in reproductive success (determined by number of matings) encourages risky behaviour. Male characteristics as influenced by sexual selection: Appearance: symmetry over fluctuating asymmetry, bigger size, brighter colouration to benefit offspring of female. Behaviour: courtship behaviour which may include useless make-work behaviours to show the female that he has expendable energy and is resourceful. Females initiate courtship by engaging in proceptive behaviours during the estrus period of their estrous cycle. The level of sexual dimorphism between the sexes can indicate the amount of male investment in reproduction.
