UNIT 5 DAY 3 - Kin Selection And Altriusm Flashcards
Altruism
- any act that aids another individual at a cost to the altruist
- selflessness
- eliminating any individuals foolish enough to offer resources to others instead of keeping them for themselves
3 explanations for altruism
- group selection
- kin selection
- reciprocal selection
Group selection
- if all individuals work for good of the group, species will expand and experience greater success (artic lemmings example)
Kin selection
- selection that favours altruism among relatives
Gene-centred perspective
- George Williams
- argues evolution by natural selection best understood as selection acting on genes
Why does natural selection favour altruism
- selection in the end is not about efficiency or survival, but about putting the most and the best babies put into the world
Richard Dawkins: the selfish gene
- image that genes are the target of selection, rather than individuals
- genes persist through many generation repeatedly tested by selection
- individuals last only a lifetime never to be repeated in the future
Reciprocal selection
- sacrificing for the benefit of a recipient who is not closely related, where a return benefit may be given in the future
How might a gene go about placing itself into the next generation
- one way would be to team up with other genes to make an organ that helps the body in which the gene dwells and survive and reproduces
- another is to make a costly handicap (long tail/carotenoid rich throat)
- it would increase the chance that copies of itself would be transmitted via sperm to the next generation
How is parenting in altruism
- diverting energy into eggs or milk, or protecting ones offspring at a risk to ones self, are acts that aid the offspring at a cost to the parent
- parents that selfishly keep all resources to themselves will live longer but they will have no offspring
- a population that starts with a mixture of altruistic and selfish parents will soon be only altruistic parents, because only altruistic parents will have descendants
Why meerkats are altruistic
- meerkat groups are actually big families, most or all members are kin
- when subordinate meerkats help the dominant female to raise her the latest brood, they are actually helping to raise sisters, nephews and grandnieces
- the genes that direct caregiving in the subordinates have a reasonable change of also being in the newborns who benefit from their care
- since the dominant female kills their offspring, helping raise nephews and grandnieces is better than nothing at least until the subordinate is forced out of the group to form her own group or die
Hamilton’s rule
rB greater than C
B = number of offspring produced by the beneficiary
C = the number of offspring fewer than the altruist would produce
r = coefficient of relatedness, the fraction of genes that are shared
Inclusive fitness
Total number of surviving relatives of an individual weighted by their relatedness to her
How humans differ from other animals
- cultural influences (often encouraging altruism)
- reason can function without genetics
- people impose better who relatives are
what does hamiltons theory of kin selection predict about how individuals behave within families as opposed to how they behave in other social groups
- the social dynamics of family life is expected to differ in significant ways from the dynamics of other types of groups living
- although we expect significant amounts of cooperation within families, we must also recognise that not all family interactions are harmonious
- kinship may temper selfish behaviour because it doesn’t not eliminate it
- indivisos will often differ in their degrees of relatedness to one another in their opportunities to benefit from others and in their abilities to wield leverage over others
