Anthropology 116 – Sexual Selection
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Bad Ideas?
o
Phenotypes that are detrimental to survivorship
Seems to contradict Darwin’s idea of natural selection
Male lifespan is significantly lower than females in mammals
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Even after “stupid behavior” is accounted for
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Function of how male bodies operate
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During mating season – exhibit a sharp increase in mortality
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For humans – mortality peaks at around 20 years
External causes peak at 20 and then decline
Internal cause are consistently increasing after
birth
Ex: Ache – tribal people group in south America
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Hunt a small rodent like creature called a “kande”
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Behave like squirrels
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Go out in a semi-circle with bows and arrows and
imitate the sound of a jaguar
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Herd them into a tree
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Make lots of noise with branches and bows and arrows
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“Kande” panic and start jumping out of the trees
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Grab them by the tail while they are in the air and
swing them around and bash them into something hard
If you don’t kill or knock him out right away
they will turn around and fight – the “kande” are
vicious
Only the young Ache do the hunting – trying to
prove themselves
Peak right around the same time – 20’s
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Females have a higher probability of death up until twenties
due to infanticide
o
Physical characteristics
Ex: Fiddler crab’s huge claw
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Large claw takes more energy to maintain (males have the
larger claws)
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The large claw is used as defense for females
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Increase in reproductive success but a trade of lifespan
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Gull predation
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Straight run
Attempts are equal against both males and
females – success is about the same as well
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Angles run
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Mostly attack males and are very successful;
however completely unsuccessful against the

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- Fall '08
- AGWUELE
- Anthropology, Reproduction, females, males, Sexual Selection, Sexual dimorphism
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