GradeBuddyANTHRBIO 201 1st EditionLecture 14Nice Monkeys? Kinship and altruismKin groups in monkeys and apes Japanese macaques Snow monkeys matrilineal group structure in old world monkeys social activity revolves around subsets of genetically related females when males reach sexual maturity they take off and leave the homes Patrilineal group structure in chimpanzees females are the dispersing sex Kin correlated behaviorsGrooming patterns on who grooms who close genetic relatives coalitions 2 or more individuals direct aggression apparently altruistic behavior acts which are performed at a clear survival/reproductive cost to the actor thats interveningthat benefits another individual creates puzzle for natural selection Natural selection and the paradox of altruism Darwin’s perspective every complex structure should be useful to the possessor never partial solution genes are the units of inheritancenot the individuals genes are shared nonrandomly likely to share genes with siblings a counterexample of apparently altruistic behavior: alliances How to resolve? IV. Kinship and the evolution of altruismunit of inheritance inclusive fitness fitness of others due to the help of ego and devalued by the degree of relatedness between ego and recipient conditions favoring altruism B=benefit to the recipient C=cost to the donor r=coefficient of relatedness between donor and recipientrB>C resolving the paradox V. Examples of kin selection VI. Reciprocal altruismif an individual helps another at a relatively little cost today, but later receives “repayment” from the recipient, then the actor will experience a net reproductive benefit from its initial behavior conditions favoring the evolution of reciprocal altruism individuals interact often are capable of remembering who supported them in the past support only those who help them reciprocal meat sharing in chimpanzees meat is shared nonrandomly and reciprocally among males unrelated