Lecture 16 - Social Behaviour: Cooperation & Altruism

how do meerkats exhibit altruistic behaviours?

they generate ground calls to warn others of predators in the environment but this draws attention to themselves putting them in danger

cooperative breeding

helping others with reproduction but foregoing breeding for themselves

eusociality

an elaborate form of social organization involving a reproductive division of labor among members, overlapping generations and cooperative care of the offspring

eusociality in ants

one defends the leaf and the other carrier the leaf

social behaviour

the interaction with and responses to other individuals of the same species

cooperation

any positive interaction between individuals, behaviour that if adopted by two or more individuals benefits both

altruism

behavior increase another individual’s fitness for survival of reproductive success at a cost of one’s own fitness

why would individuals risk themselves to help others?

due to shared direct benefits, reciprocity and kin selection

shared benefits in female lions

if only one female lion is caring for her young she faces the cost of energy and potential injury for the benefit of offspring survival but if there were two females offspring survival is more likely and cost isnt as likely

Hawk strategy

fight aggressively

Dove strategy

resolve contest peacefully

dove vs dove

reward split evenly between the two

dove vs hawk

hawk gets the reward and dove gets nothing

hawk vs hawk

split between both but they suffer cost of fighting

if reward is double the cost what is the best strategy?

always play hawk

if cost is double the reward what strategy is best?

fitness of strategies is frequency dependent so if hawk is more common play dove and vice versa

what should you do for the best outcome in the prisoner’s dilemma?

confess/defect always

what should you do in the iterated prisoner’s dilemma?

cooperate on the first encounter then copy opponents last move the following encounters

how do guppies show reciprocity in light of predator inspection?

if they see that their partner is cooperating and going towards the predator they’ll do it too and if the partner is defecting by running away from the predator they’ll do the same

kin selection

difficulty is lessened or disappears when it is remembered that selection may be applied to the family as well as the individual and therefore may gain the desired end

who has better fitness when altruism is directed toward a random individual?

the random person/non altruist

long tailed tits

if they had to choose between kin and non kin in the same social group they predominantly direct altruistic behaviour to kin

who has better fitness if altruism is directed toward a genetic relative?

maybe altruists cause they get direct fitness and the relative gets indirect fitness

hamilton’s rule

we expect greater altruism to be directed towards closer genetic relatives (br>c)

stalk forming cells in social amoeba

they die

spore forming cells in amoeba

they have a chance to disperse and reproduce more amoeba

how do amoeba show kin selection

they discriminate kin from non kin by co aggregating with genetically similar individuals only

how does natural selection fit into this explanation for altruistic behaviour?

shows that it cant favour self sacrificial genes but it can favour self sacrificial individuals if through that sacrifice underlying self sacrificial behaviors are getting passed on too