Chapter 20-Animal behavior

cooperative breeding

certain individuals forego reproduction (lose direct fitness) and devote energy to rearing the young of relatives, often siblings

cooperative breeders

called helpers

altruism

an action that reduces and individual’s potential direct fitness (number of offspring produced) while increasing the fitness of another individual

fitness

number of individual’s alleles transmitted to the next generation

direct fitness

fitness gained through allele transmission by offspring

indirect fitness

fitness gained through allele transmission by helping relatives rear their offspring

inclusive fitness

fitness gained through both direct and indirect fitness

kin selection

evolutionary strategy in which organisms forego reproduction (lose direct fitness) to benefit a relatives reproductive success (gain indirect fitness)

why is cooperative breeding and kin selection selfish

ultimately increases the total fitness of the helper

when is cooperative breeding most likely

when the helper is more related to the relative’s offspring

relatedness ®

the probability that two individuals share a given allele

inclusive fitness

direct fitness+indirect fitness=direct fitness+(r x benefit from helping relatives)

hamilton’s rule

individuals should behave altruistically (help raise relatives offspring) IF fitness gained is greater than fitness lost from not reproducing