TASK 4 Flashcards
Cooperation
Reproduction restraint
Adaptations that evolve because it increased the likelihood of survival for the population in bad times
Evolutionary stable strategy (ESS)
- Strategy which cannot be invaded by an alternative strategy that is initially rare
Kin selection
- 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
Hamilton’s rule
- 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
Inclusive fitness
- sum of personal fitness and fitness resulting from helping a relative
- -> direct fitness (number of offspring) + indirect fitness (offspring produced by relative)
Alloparenting
- relative/individual other than the biological that performs the functions of a parent –> takes care of offspring
Cooperation
= Action/process of working together to the same end
- True altruism
- Mutual-benefits behaviour
Altruism
- Selfless concern for the well-being of others
- behaviour that benefits others at costs for the actor
Mutual-benefits behaviour
Behaviour that is beneficial both to the actor and the recipient
By-product benefits
Situations where the mutual benefit arises simply from every individual following its own immediate self-interest
Direct reciprocity
= 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
Indirect reciprocity
- 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
Green beard effect
- 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
Eusociality
- 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
Reproductive altruism
Behaviour that increases other organisms’ fitness and permanently decreases the actor’s own fitness
Parochial altruism
- Self-sacrifice to benefit our own group (“in-group love”)
- hurt or sabotage out-groups (“out-group aggression”)
Network reciprocity
- 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
Group selection
= 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
Prisoner’s dilemma
- 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
Grudger
Always co-operates unless the other defects –> then he only defects (he is pissed off)
Tit-for-tat “nice” strategy
- 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
Tit-for-two-tat
= Forgiving tit-for-tat
- 2 defections are required/’allowed’ before person using this strategy gets “pissed off” and defects as well
Joss
Strategy that is basically tit-for-tat but sometimes tries defecting
Tester
Strategy starts of cooperating –> defects to see what the opponent does and to find out their strategy
Generous tit-for-tat
If the other cooperates, you cooperate –> if the other doesn’t cooperate, you sometimes do not cooperate as well
Stay-loose-shift
You keep your strategy as long as you win –> if you lose, you change your strategy
Ultimate explanations
- 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
Proximate explanations
- HOW something occurs
- concerned with the mechanisms that underpin the trait or behaviour
- ontogeny: development of mechanism
- genotype –> phenotype
Group viability selection
- groups are less likely going extinct
Group fecundity selection
- groups of co-operators have higher rate of replication/making offspring
Haplodiploidy
- 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)
