Altruism, Spit, Cooperation, Selfishness Flashcards
what are the 4 ways that social behaviour between groups of animals can be divided?
Selfishness, Altruism, Cooperation and spite
what does selfish behaviour involve?
selfish behaviour is straight forward natural selection, acting to maximise your fitness as much as possible- the strongest and fittest wins
what does cooperative behaviour involve and why is it an unexpected behaviour?
it would not be expected that animals would cooperate as in a population of pure cooperators, defection can invade. this can be seen from the prisoners dilemma:
cc:3
cd: 0
dc:5
dd:1
so defection is the ESS as can invade pure coops and can’t be invaded by coops
- therefore it is surprising that cooperation can evolve
- but it can when there is reciprocity- vampire bats will only cooperate with coop vampire bats
-OR if the one cooperating gets a direct benefit i.e a bird helping other bird rear young- get experience and mating ground
why is altruism an unexpected behaviour?
it harms the actor, the actor reduces its own fitness at the cost of other, this doesn’t fit into natural selection… or does it?
who first came up with an explanation for altruism and what did he say?
Bill Hamilton realised that fitness was a transmission of genes to the next generation and this can occur directly or indirectly. the evolution of a trait depends on effect on the bearer’s fitness and the effect on the fitness of others- this is called inclusive fitness.
what is inclusive fitness?
the concept that the fitness of a mutation can be increased through the bearer contributing as much as possible to the next generation OR by the bearer ensuring another bearer contributes as much as possible
when can an altruistic mutation invade a selfish population?
when the altruistic behaviour increases the fitness of other carriers of the mutation- hamilton rule rb>c
what is hamilton’s rule?
altruism invades if the cost of behaving altruistically is smaller than the benefit x relatedness- relatedness is important because shows they carry similar genes
rb >c
what is kin selection?
Kin selection is the evolutionary strategy that favours the reproductive success of an organism’s relatives, even at a cost to the organism’s own survival and reproduction. Kin altruism is altruistic behaviour whose evolution is driven by kin selection
how can you test kin selection and hamiltons law?
looking at slime mould
- when slime reproduces under stressed conditions each amoeba comes together to form a stalk which allows a spore to form at the end, the spore is then released
- obviously those that enter the stalk are sacrificing their own fitness for the sake of their relatives- this is therefore kin selection
- every time a population spores- mix into another strain and repeat- see if the evolved strain becomes more selfish
- yes it does- when mixed with ancestral population more evolved are found in spore than neck- have become more selfish as they have developed where their neighbours are less related- good to be selfish when neighbours are related
what are examples of kin selection in ‘non social’ behaviours?
evolution of dispersal- leaving resources for the reproduction of. this has a benefit of reducing competition between relatives- more likely that all will contribute to next generation: this is seen in common lizards- offspring are more likely to disperse the young their mother is, so not to compete with her or her offspring- however as the mother gets old and ‘b’ decreases, they are more like to fight mother
how can spite be explained using hamilton rule?
if you harm somebody who isn’t related to you then your genes are more likely to pass on and theirs aren’t- if the cost of you acting spitefully is less than the benefit your genes will gain from them producing less (reduce competition) then you will act spitefully. negative relatedness
why is spite rare in nature?
hard for spire to invade so spite is rare as the effect of reducing competition is often reduced in large population sizes and harming others reacquires genetic recognition cues
what is an example of spite in the nature?
- there are two social forms of a species of fire ant
- one is a monogynous colony with 1 queen
- the other is a polygons colony with multiple queens
- there is a marker locus gp9 in monogynous colonies the queens are BB and the workers are BB
in polygnous colonies queens are Bb and workers are BB or Bb - in polygnous colonies- BB queens are eliminated by Bb as they want to spitefully eliminated non b carriers- b allele is linked to a selfish gene
what is the marker locus in fire ants?
gp9
