Natural selection 2.0

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Offline Sciencemd68

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Natural selection 2.0
« on: 06/02/2012 04:40:28 »
I have a hypothesis about the evolution of the peacock's tail and other seemingly malevolent adaptations that are surprisingly persistent. Most believe the flamboyant tail is a signalling mechanism that allows hens to discern which male is truly fit. In other words, if two males finished a race at the same time, one unencumbered and one carrying a 25 lb sack on his back, you would assume that the sack toter was more physically fit than the other. However, the philandering males, who contribute nothing to chick rearing, have the potential to overpopulate and exploit the hens who are vulnerable to predation while caring for a large brood. To ensure a viable ratio of the sexes for optimal chick survival, I think the peahen selects for the tail to ensure that the philandering male dies relatively soon after mating. She is only a little more subtle than the black widow spider. Birds who require the male to participate in chick rearing are rarely if ever dimorphic (think penguins, swans, birds of prey). Similarly, mammals, (elephant seals, deer species) where the male contributes little to child rearing have males with impediments as well, like antlers or fighting or increased testosterone (which is immunologically bad) which leads to a definite decrement in male life span. The females are perhaps selecting for these traits so that the result is uber fit males that nonetheless die young so there is more forage for the young.
I realize that there are cogent explanations for these phenomena, but they never seemed to explain why a male would evolve to reduce his fecundity. Perhaps the females are selecting these traits for their offsprings' well being and the male "goes along" with it because in dying young more off his offspring survive.