Altruism Lecture

Question 1

What did Wynne-Edwards demonstrate?

Answer 1

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.

Question 2

What is hamiltons rule?

Answer 2

rb>c, where r is relatedness, b is the benefit to relative and c is the cost to self.

Question 3

What is direct fitness?

Answer 3

A measure of the number of surviving offspring

Question 4

What is indirect fitness?

Answer 4

A measure of the number of surviving relatives

Question 5

What is inclusive fitness?

Answer 5

all the offspring that an individual produces plus all those additional offspring or relatives that the individual helped.

Question 6

What does inclusive fitness predict?

Answer 6

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.

Question 7

What does kinship allow?

Answer 7

Close relatives to evolve altruistic behaviour.

Question 8

What ways can animals discriminate kin?

Answer 8

Associations in time and space, familiarity, phenotype matching or recognition alleles.

Question 9

What are associations in time and space?

Answer 9

This is how animals can use location to identify kin. However this can be exploited for example by cuckoos.

Question 10

What is familiarity>

Answer 10

This is how animals elarn about who is likely to be related to them for example developing in communual nests is suggestive of siblingry,

Question 11

What is phenotype matching?

Answer 11

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.

Question 12

What are recognition alleles?

Answer 12

These are where animals have a genetic template of themselves.

Question 13

When can altruism occur without kin selection>

Answer 13

When they help you in return, known as reciprocal altruism (Trivers, 1971).

Question 14

What strategy should be used for reciprocal altruism?

Answer 14

Models predict animals should play “tit for tat”.

Question 15

Why might reciprocal altruism be rare?

Answer 15

There are cognitive constraints on this type of cooperation.

Question 16

How can reciprocal altruism evolve?

Answer 16

If there are repeated interactions, if the benefit is greater than the cost, and if the animals possess the appropriate cognitive abilities.

Question 17

Give an example of extreme alturism?

Answer 17

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.

Question 18

How are alarm calls an example of altruism?

Answer 18

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.

Question 19

Dawkins quote on altruistic systems?

Answer 19

“Any altruistic system is inherently unstable, because it is open to abuse by selfish individuals, ready to exploit it.”