Cooperation and kinship

altruistic behavior

improves fitness of the receiver but harms fitness of the giver

is cooperation evolutionarily stable?

not in one-off interactions but it can be long term

conspecific

belonging to the same species

enforcement

manipulating an individual into doing a certain thing, e.g. teaching a dog not to eat human food

is behavior always done in self-interest?

no, like birds helping carry food or lions allying to challenge the leader

vampire bats and reciprocity

unsuccessful foragers get food from roost mates and will help out later on

is cheating better within groups or between groups?

within

is cooperation better within groups or between groups?

between

cooperative colony in ants

queens work together until workers arrive, then only help their own groups b/c there is no between group benefits

kin selection

helping a related individual indirectly makes sure your genes live on

direct fitness

gained from raising your own offspring

indirect fitness

gained through aiding the survival of your relatives

inclusive fitness

direct fitness + indirect fitness

coefficient of relatedness (r)

the probability that two organisms share identical copies of the same allele by descent

r for siblings

0.5

r for cousins

0.125

r formula

∑(0.5)^L  where ∑ is the sum of possible paths, 0.5 is the probability of successive genes sharing an allele, L is the number of generational links between two individuals

hamilton’s rule

altruistic behavior can evolve by kin selection if rB-C > 0 where r= coefficient of relatedness, B=benefit to receiver, C=cost to giver

wild turkeys and indirect fitness

pairs of related males ‘hunt’ females, the subordinate male gives up his direct fitness for the indirect fitness of the dominant male