Animal behaviour- parental care: many species parents provide no care for young: most insects, amphibians and reptiles (eg sea turtles) In some species parental care is the rule: some insects, amphibians and reptiles (eg. crocodiles), many fish and all birds, all mammals. Animals provide parental care in many ways: food, heat for young unable thermoregulate, heat dev eggs birds and some reptiles, protection from predators. Care by m, f/ both: uniparental f- many mammals, uniparental m- many fish, biparental care- most birds= unsure why but could do w accelerating rate dev young- can provide advantage avoiding predators. Idea parental invest helps explain conflict b/w parents and offspring: conflict amount parental invest, conflict over when parental investment ends, as offspring become indep, bens decrease. Group selection: altruism evolves b/c altruistic groups persist longer than selfish groups- group ben= group selection (units nat selection group not individ, requires, isolated groups, low rate immigration (less 1/ generation, high rate of group extinction.