altruism Flashcards
altruism
an individuals behaviour that benits another’s fitness at self expense
example of an altruistic primate behaviour
vervet monkey s giving predator calls
group selection
wyneed edwards theory 1962; unit of selection is the group
‘whats good for the species is food for the individul’
kin selection
altruism among biological relatives (shared genes= extension of the individual)
example of kin selective behaviour in a primate
marmosets; will ‘wing man’ the more attractive brother as more offspring acan be produced by him
inclusive fitness
an individuals TOTAL fitness measured by direct/indirect fitness effects of an action
direct benefits of inclusive fitness
own reproductive success
indirect benefits of inclusive fitness
the success of a relative= some of YOUR genes keep going
hamiltons rule
degree of relatedness (r)= determines the extent of collaboration
c< bXr
where c= costs of act to individual
b= benefits of act to recipitent
r= degree of relatedness between individuals
reciprocal altruism
form of mutliaims; self-cost beahaviour taken under assumption it will ‘pay off’ with an equally valuable act
multi-level selection
the OVERALL fitness of a group is increased by collaborating altruists:
what needs to happen for multi level selection altruism to work
- each altruist can perform simila acts of altruism
- repeated interactions
- low dispersal rates
- egaliterian social systems
- cheatesr must be punished to enforce altruism as a norm
hare and tan 2013 studied…and found…
bonobos! they are unique apes who prefer interacting with strangers than with own group (more likely to share food) = expand their social network!
summary of altruism
a single altruist must have lower fitness when surrounded by a goup of selfish individuals
BUT
an individual living in a group of altruists has higher fitness than an individual in a group of selfish members
kurland 1977: evidence of japanese macaques
close female kin spend more time together to support each other;
hence groom each other more and fight less
vervet monkeys and kin selection example
response faster to calls of kin in fights and especially to kin who recently groomed them
chimp society kin selection
male ‘brother’ bands
male rhesus monkey kin selection
natal dispersal occur; brothers tend to stay togther more and support rank rising
alianceses more likely and more mating sharing
alloparenting; benefits?
group parenting and cooperative breeding:
- allows for children to slowly development= leads to larger brains
- mothers conserve energy
- increased predator protection
- increased access to resources
critique of group selection
selfish would outcompete altruists faster as they would have a higher alturistic effect
who proposed the idea of multi-level selection
sober 1993
sloan wilson 1997
misplaced parent hypothesis
by Sarah Hrdy:
cute helpless kids give signals that attract adults to care for it (hence altricial infant species tend to have cooperative behaviour)
when might parents help a kin
when no self0serving option is availiable (only when excess food)
when there is a dominance structure (subordinates care for dominants like in meerkats)
