Altruism, inclusive fitness theory

Question 1

What are some of the solutions to the altruism and cooperation problem, namely, how can you explain that altruism and cooperation have evolved?

Answer 1

1. Kin selection and inclusive fitness, altruism among relatives
2. Multi-level selection (group selection 2.0)
3. Parochial altruism: altruism becomes adaptive when paired with parochialism because together with your group you profit from hostility towards the outgroup. Investigated with intergroup prisoner’s dilemma.
4. Reciprocal Altruism. Altruism = Cooperation: mutual benefit behaviours that evolved through direct and indirect reciprocity

Question 2

Why is Wynne Edwards theory of group selection of altruism wrong? Use the example of altruistic birds and reproductive restraint.

Answer 2

Models show that when birds are altruistic and they show reproductive restraint, that population will last slightly longer than the population of selfish birds because there are less birds to share food with.
However, within the population, the proportion of altruistic birds will decrease until there are none left, compared to the selfish birds. Because the selfish birds will reproduce more.
Therefore, even though it might serve the population (group selection), the individual does not have higher reproductive success and altruistic alleles will have lower fitness and die out.

Question 3

Hamilton’s rule

Answer 3

c < rb

Question 4

What is cooperation?

Answer 4

Behaviour that provides benefits to individuals other than the actor and that have been selected because they do so.
Altruism is a subform

Question 5

What is altruism?

Answer 5

Acts that increase another’s fitness at the expense of the individual’s fitness

Question 6

What is a precondition for mutual benefit behaviours to be able to exist?

Answer 6

• it is only maintained if there are strategies against cheating, otherwise cheating individuals will be even higher in fitness than cooperating individuals.

Question 7

Direct reciprocity characteristics

Answer 7

c < wb with w the probability of the person reciprocating
Direct reciprocity is a way that mutual benefit behaviours could evolve.
Individuals must re-encounter.

Question 8

Indirect reciprocity characteristics

Answer 8

c < qb with q the probability of having correct info
Especially important in humans due to language, gossiping is very prevalent. Also necessary in humans bc the large population makes re-encounter unlikely.
Important is establishing a good reputation: even subtle cues can affect this like eyespots.

Question 9

Eusociality characteristics

Answer 9

• overlapping generations
• cooperative brood care
• extreme altruism by giving up own reproduction
• philopatry: remain living at birthplace
• particularly common in Hymenoptera (bees etc)

Question 10

What is multilevel selection?

Answer 10

The newer idea of group selection.
Selection happens on individuals as well as groups.
1. population is divided in groups, which grow due to offspring
2. once a group reaches a certain size it splits (‘group reproduction’: those groups that do well grow faster, split more often)
3. selection within group favors defectors, selection between groups favors cooperators.

Question 11

What is the greenbeard effect?

Answer 11

A possible explanation for why altruism may have persisted. If altruists are only altruistic toward other altruists (green bearded altruists being altruistic towards people with green beards), then altruism has higher fitness.
Precondition: gene must be able to recognize presence gene in others because of a resulting phenotypical characteristic (eg friendly people)

Question 12

Morality and guilt: ultimate or proximate explanation of altruism?

Answer 12

Proximate

Unrelated to adaptation (fitness) so unrelated to the question: does true altruism exist