Altruism Lecture Flashcards
What did Wynne-Edwards demonstrate?
Group selection illustrates the problem with helping behaviour. If some individuals show helping behaviour but others do not then they will do better than you. Co-operative behaviour therefore isn’t evolutionary stable.
What is hamiltons rule?
rb>c, where r is relatedness, b is the benefit to relative and c is the cost to self.
What is direct fitness?
A measure of the number of surviving offspring
What is indirect fitness?
A measure of the number of surviving relatives
What is inclusive fitness?
all the offspring that an individual produces plus all those additional offspring or relatives that the individual helped.
What does inclusive fitness predict?
That helping should be more prevalent in family groups than less closely related groups. This is found to be true as 96% of birds and 90% of mammals that live in family groups show co-operative breeding.
What does kinship allow?
Close relatives to evolve altruistic behaviour.
What ways can animals discriminate kin?
Associations in time and space, familiarity, phenotype matching or recognition alleles.
What are associations in time and space?
This is how animals can use location to identify kin. However this can be exploited for example by cuckoos.
What is familiarity>
This is how animals elarn about who is likely to be related to them for example developing in communual nests is suggestive of siblingry,
What is phenotype matching?
This is how individuals use themselves as a template rather then learning about others. Frog tadpoles prefer to associate with siblings over non-siblings even when reared apart.
What are recognition alleles?
These are where animals have a genetic template of themselves.
When can altruism occur without kin selection>
When they help you in return, known as reciprocal altruism (Trivers, 1971).
What strategy should be used for reciprocal altruism?
Models predict animals should play “tit for tat”.
Why might reciprocal altruism be rare?
There are cognitive constraints on this type of cooperation.
How can reciprocal altruism evolve?
If there are repeated interactions, if the benefit is greater than the cost, and if the animals possess the appropriate cognitive abilities.
Give an example of extreme alturism?
Worker bees have barbed stings and attack predators which approach their nests. By stinging the predator the worker bee dies. This suicidal behaviour has evolved because the beneficiaries are close relatives of the worker bee.
How are alarm calls an example of altruism?
Female squirrels are more likely to give alarm calls, and females with close relatives nearby were more likely than females without close relatives nearby. This demonstrates that individuals are more likely to incur the cost of calling when relatives are nearby to gain the benefit.
Dawkins quote on altruistic systems?
“Any altruistic system is inherently unstable, because it is open to abuse by selfish individuals, ready to exploit it.”
