Sex2Lect - Why Is There Sex? Hedge against environmental...

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Why Is There Sex? · Hedge against environmental change · No current reason for humans – phylogenetic inertia · Protection against pathogens – Red Queen hypothesis The Sexes and Sexual Selection · “Female” – sex that makes the larger parental investment per gamete. · “Male” – sex that makes the smaller parental investment per gamete. · Sexual selection – a type of natural selection in which members of one sex compete for repro- ductive access to members of the other sex. · The means of competition can be structural or behavioral, and often lead to sexual dimorphism. Sexual Dimorphism · In most of animal kingdom, females are much bigger than males. · One major exception is in species with proportionally large brains. · In those species, males compete for females with displays of strength and prowess. · Females choose mates based in part on these displays o Overt female choice (“I want you”) o Cryptic female choice (reject/accept sperm) Mating Systems · Monogamy - pair-bonding · Polygamy – one animal has many mates o Polyandry – one female mates with many males o Polygyny – (harem) – one male mates with many females · Promiscuity (chimps- females will mate with as many males) Some Features of Human Mating System I · Mostly monogamy with some polygyny · Male > Female Preference for sexual variety o More diverse arousal patterns Fetishes (foot fetish) Exhibitionism Criminal patterns: rape, child sexual abuse o Numbers of partners - - males are: less picky about people less careful about circumstances
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Mating systems: Standard Cross-Cultural Sample (186 Cultures) · Most human cultures allow polygyny · In those cultures, polygyny is restricted to the well-to-do minority, and most men in these cul- tures have only one wife. · Overall, the vast majority of marriages are monogamous. · In every society studied to date, female extramarital sex is considered an offense against her hus- band, and is often grounds for murder of wife and/or lover.
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This note was uploaded on 10/11/2011 for the course PSY 1 taught by Professor Fridlund during the Fall '08 term at UCSB.

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Sex2Lect - Why Is There Sex? Hedge against environmental...

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