Lecture_07_cooperation-2

Lecture_07_cooperation-2 - Lecture 7: Coooperation Why it...

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Lecture 7: Coooperation •Why it can be more “selfish” to share? Cooperation and mutual helping behavior among humans is common both in very simple societies and in complex modern societies. Biologists recognize behaviors that are costly to an actor but beneficial to another individual as ‘altruism’. Altruism appears to violate the selfish individualistic character of natural selection- yet it is commonly observed. Help directed towards juveniles is common in many organisms. This is especially common when the adult helper is a parent or closely related. But altruistic acts between unrelated adults in mammals are extremely rarely reported. Adult primates are seem to groom each other, and help each other in social confrontation, and a few primate studies have shown altruistic cooperation between reciprocal partners. For example baboon males sometimes take turns fighting off other males and copulating with a female that guard together (dolphin males do the same thing). And capuchin monkeys will share food with each other if they are placed in a situation that requires work by both of them to obtain a food reward that is available to only one of them. And capuchin monkeys will share food with each other if they are placed in a situation that requires work by both of them to obtain a food reward that is available to only one of them Human adults typically help other adults many times a day. For example, Ache hunter-gatherers spend a large percentage of time
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helping others acquire food when they can get nothing directly from their actions. How can we explain the evolution of altruistic behaviors—behaviors in which individuals help others seemingly at their own expense? Two general pathways to cooperation based on individual benefit: 1)Kin selection; 2)Reciprocal altruism. A simple chart that shows the kinds of actions possible between an actor and a recipient of the action; pluses and minuses reflect the impact on each individual’s fitness: RECIPIENT: Benefits(+) Is harmed(-) Benefits(+) mutualism/ selfishness/ Cooperation exploitation ACTOR: Is harmed(-) Altruism Spite ******************************* I.Kin selection William Hamilton suggested that altruism could develop among related individuals, because relatives share a proportion of their genes . Hence, an allele that caused an individual to help a relative would be increasing its own fitness as well (because the same allele is likely to be found in the relative). The probabilities of any individuals sharing alleles through common descent can be easily estimated based on the rules of Mendelian genetics.
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For example the probability that a child shares an identical copy of any one particular gene in the parent is 1/2 . Full siblings also have a 1/2 chance of sharing a particular allele since any allele they receive from mother or father has a ½ chance of being passed to any other
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This note was uploaded on 03/24/2010 for the course ANTHRO 101 taught by Professor Osbjorn during the Fall '09 term at New Mexico.

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Lecture_07_cooperation-2 - Lecture 7: Coooperation Why it...

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