SBCC ANTH 103 - anthro assing. why sex (3 pages)

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anthro assing. why sex



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anthro assing. why sex

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Pages:
3
School:
Santa Barbara City College
Course:
Anth 103 - Intro To Cultural Anthropology

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Why Sex ANTH 103 1 Benefit of sexual reproduction is that it increases genetic variability Sex generates variability among offspring And when you take that away from a sexual reproducer by inbreeding them cloning them you ve lost the very benefit of sex It s that generation of an immense amount of diversity that diversity of your offspring that provides challenges to everything around it challenges to the parasites challenges to the viruses challenges to your competitors Sexual process the variation and wonderful diversity it creates The easiest way for an organism to reproduce is simply to divide asexually to make a copy of it An organism that reproduces sexually however must divert precious energy into making sperm or egg cells in the process gene combinations that were quite useful beforehand are sometimes destroyed through recombination Then the organism must find a member of the opposite sex and mate with it successfully From an evolutionary perspective sex incurs considerable costs that must be offset by advantages to the organism 2 Male Quantity Organisms with reproductive cells like that are called males Males produce sperm by the millions with so many potential offspring it doesn t pay to be fussy about eggs A better strategy is to try to fertilize every egg you can Female Quality Their goal is to find organisms with a different specialty providing the nutrients life requires Females make only a limited number of them Eggs are more complex than sperm and take a larger investment of energy Females engage in choice while males engage in competition Male competition may take the form of fighting Bird in Panama survival of chicks is so uncertain it s led to an amazing gender role reversal Male sex competes for mates Female invests in the young 3 Caring young offspring The young have to survive long enough to have their own offspring Sometimes that requires paying as much attention to behavioral traits as to physical ones For some species the chances of offspring surviving increase if a female chooses a mate who ll stick around over the one with the best genes 4 Songbird returning from migration sometimes has to settle for a fairly low quality male in comparison with her neighbors The female is now torn between a desire to have a faithful mate who will help her raise her young and a desire to have her chicks sired by a male of higher genetic quality Cheating at least for certain female songbirds gives their chicks better genes and therefore a better chance of surviving until they can reproduce Behavior of males and females depends on which sex competes for mates and which invests in the young Yet the males of these Panamanian birds still produce sperm and the females still lay eggs Bird in Panama survival of chicks is so uncertain it s led to an amazing gender role reversal So many chicks are lost to crocodiles that females leave their eggs for the males to raise and



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