Evolution of Cooperation Flashcards
Define cooperation
that selfish replicators forgo some of their reproductive potential to help one another
How is cooperation different from mutualism
cooperation is in terms of members of the same species where mutualism is between members of different species
Examples of cooperation
- biparental care (seahorses, waterfowl)
- allopreening/social grooming (to remove ectoparasites and maintain plumage condition)
- vigilance behaviour (increasing awareness of predator presence)
- reciprocal food sharing
- eusociality (highest level of organization of sociality)
DEFINE prisoner’s dilemma
a metaphor for the obstacles in the way of cooperation
to either stay silent (and cooperate) or defect against (and be selfish)
EXPLAIN prisoner’s dilemma
two accused prisoners, can either cooperate with one another or defect against the other. the result is how many years spent in prison (payoffs)
C D
C R/R S/T
D T/S P/P
R = T= S= Sucker P= Punishment
Therefore
T>R>P>S
What are payoffs in the prisoner’s dilemma equivalent to in real systems
evolutionary fitness, however difficult to measure payoffs in real life
Results of prisoner’s dilemma
- always better to defect rather than cooperate (T>R and P>S)
- yet everyone would be better off under mutual cooperation than mutual defection (R>P)
Five rules for the evolution of cooperation:
- Kin selection
- direct reciprocity
- indirect reciprocity
- network reciprocity
- group selection
Explain kin selection as evolution for cooperation and example
where individuals forgo their own reproduction to assist with reproduction of a close relative
ex. parental care
what equation of kin selection anticipates the drive of evolution of cooperation
r>c/b
r=coefficient of relatedness
c=cost of cooperation to donor of cooperative behaviour
b = benefit of cooperative behaviour to recipient
Explain direct reciprocity as evolution for cooperation
where individuals help those that have helped them, if interactions are repeated it is possible for cooperation to emerge
Example and equation of direct reciprocity
w>c/b
w = probability of another encounter
ex. reciprocal food sharing in bats
Example tit-for-tat strategy in direct reciprocity
in repeated encounters, TFT always cooperates at first, then if others cooperate then also, but if they defect then they will also defect.
the 4 traits of the strategies that caused for the highest fitness payoffs in direct reciprocity
- nice (cooperate first)
- retaliatory (if defect so will they)
- forgiving (will forgive if coop after defect)
- clear
Explain indirect reciprocity as evolution of cooperation
cooperation can evolve in individuals that are more likely to cooperate with individuals who have a deserved reputation for cooperating with others
Equation for indirect reciprocity and example
q>c/b
q = probability of knowing someone’s reputation
ex. human cooperation (because of complexity and cognitive apparatus involved)
Explain how network reciprocity can cause evolution of cooperation
clusters of cooperators tend to interact with other cooperators, allowing for the evolution and spread of cooperative behaviour
Equation and example of network reciprocity for evolution of cooperation
k<b/c
k=average number of neighbours
ex. spatial networks, individuals interact with their immediate neighbours
Explain how group selection can cause evolution of cooperation
a controversial, theoretical concept that groups with more defectors might be more likely to go extinct
Equation of group selection
1+(n/m)<b/c
n=maximum group size
m=number of groups
Why is explaining cooperation such a challenge
because natural selection seems to favour selfish behaviour and is complicated to have cooperation evolve in the face of the strong temptation of defect
