TASK 4

Question 1

Reproduction restraint

Answer 1

Adaptations that evolve because it increased the likelihood of survival for the population in bad times

Question 2

Evolutionary stable strategy (ESS)

Answer 2

• Strategy which cannot be invaded by an alternative strategy that is initially rare

Question 3

Kin selection

Answer 3

• Evolutionary strategy that favours the reproductive success of an organism’s relatives, even at a cost to own reproduction and survival
• follow Hamilton’s rule

Question 4

Hamilton’s rule

Answer 4

• Kin selection causes genes to increase in frequency –> when the genetic relatedness of a recipient to an actor (r) multiplied by the benefit to the recipient (b) is greater than the reproductive cost to the actor (c) = (r*b > c)
  OR = r > b/c

Question 5

Inclusive fitness

Answer 5

• sum of personal fitness and fitness resulting from helping a relative
• -> direct fitness (number of offspring) + indirect fitness (offspring produced by relative)

Question 6

Alloparenting

Answer 6

• relative/individual other than the biological that performs the functions of a parent –> takes care of offspring

Question 7

Cooperation

Answer 7

= Action/process of working together to the same end

• True altruism
• Mutual-benefits behaviour

Question 8

Altruism

Answer 8

• Selfless concern for the well-being of others

- behaviour that benefits others at costs for the actor

Question 9

Mutual-benefits behaviour

Answer 9

Behaviour that is beneficial both to the actor and the recipient

Question 10

By-product benefits

Answer 10

Situations where the mutual benefit arises simply from every individual following its own immediate self-interest

Question 11

Direct reciprocity

Answer 11

= tit-for-tat
- We help individuals that helped us
- needs repeated encounters between same individuals
c < w*b (w = probability of recipient to reciprocate)
OR = w > c/b
–> prevents cheaters: receive benefits but never return

Question 12

Indirect reciprocity

Answer 12

• Help is given to individuals based on their reputation –> help individuals whom we have seen help others in the past
• needs gossip (talk about others behaviour); high cognitive demands (maintain overview of network)
  c < q*b (q = probability about having correct info about reputation)
  OR = q > c/b
  –> prevents cheaters: bad reputation

Question 13

Green beard effect

Answer 13

• Explanation of selective altruism among individuals of a species –> help those who look more familiar
• Occurs when an allele produces 3 effects: a perceptible trait (the green beard), recognition of this trait by others, preferential treatment of individuals with the trait

Question 14

Eusociality

Answer 14

• Highest level of organisation of animal sociality
• cooperative brood care: parents raise offspring
• overlapping generations: generations live together
• philopatry: stay in particular area
• division of labour: reproductive and non-reproductive groups

Question 15

Reproductive altruism

Answer 15

Behaviour that increases other organisms’ fitness and permanently decreases the actor’s own fitness

Question 16

Parochial altruism

Answer 16

• Self-sacrifice to benefit our own group (“in-group love”)

- hurt or sabotage out-groups (“out-group aggression”)

Question 17

Network reciprocity

Answer 17

• If a co-operator pays a cost (c) for each neighbour to receive a benefit (b) and defectors have no costs + neighbours receive no benefits –> network reciprocity favours cooperation
  b/c > k
  –> benefit-to-cost ratio must exceed the average number of people (k) (per individual)
  b/c > k

Question 18

Group selection

Answer 18

= Multi-level selection
- behaviours come to exist because they benefit the group rather than the individual
b/c > 1+(n/m)
–> n = maximum group size, m = number of groups

Question 19

Prisoner’s dilemma

Answer 19

• Situation in which two players each have two options –> outcome depends crucially on the simultaneous choice made by the other
• -> two prisoners separately deciding whether to confess to a crime

Question 20

Grudger

Answer 20

Always co-operates unless the other defects –> then he only defects (he is pissed off)

Question 21

Tit-for-tat “nice” strategy

Answer 21

• Forgiving and allows cooperation again
• just reacts to the previous action of the other (no past and no future matters) –> only copying and therefore cannot win –> only tie or loose

Question 22

Tit-for-two-tat

Answer 22

= Forgiving tit-for-tat

- 2 defections are required/’allowed’ before person using this strategy gets “pissed off” and defects as well

Question 23

Joss

Answer 23

Strategy that is basically tit-for-tat but sometimes tries defecting

Question 24

Tester

Answer 24

Strategy starts of cooperating –> defects to see what the opponent does and to find out their strategy

Question 25

Generous tit-for-tat

Answer 25

If the other cooperates, you cooperate –> if the other doesn’t cooperate, you sometimes do not cooperate as well

Question 26

Stay-loose-shift

Answer 26

You keep your strategy as long as you win –> if you lose, you change your strategy

Question 27

Ultimate explanations

Answer 27

• WHY something occurs
• “real” reason behind a behaviour –> evolutionary function
• phylogeny: evolutionary history of mechanism
• concerned with the fitness consequences of a trait or behaviour + whether it is (or is not) selected
• phenotype –> genotype

Question 28

Proximate explanations

Answer 28

• HOW something occurs
• concerned with the mechanisms that underpin the trait or behaviour
• ontogeny: development of mechanism
• genotype –> phenotype

Question 29

Group viability selection

Answer 29

• groups are less likely going extinct

Question 30

Group fecundity selection

Answer 30

• groups of co-operators have higher rate of replication/making offspring

Question 31

Haplodiploidy

Answer 31

• males: unfertilised eggs (= parthenogenesis) –> only have one set of chromosomes
• females: fertilised eggs –> diploid
• sisters share 75% of genes –> mother and kids only share 50% (if same father)
• sisters propagate own genes more (helping mother raise more sisters rather than raise own daughters)