Evolution of Cooperation

Question 1

Define cooperation

Answer 1

that selfish replicators forgo some of their reproductive potential to help one another

Question 2

How is cooperation different from mutualism

Answer 2

cooperation is in terms of members of the same species where mutualism is between members of different species

Question 3

Examples of cooperation

Answer 3

1. biparental care (seahorses, waterfowl)
2. allopreening/social grooming (to remove ectoparasites and maintain plumage condition)
3. vigilance behaviour (increasing awareness of predator presence)
4. reciprocal food sharing
5. eusociality (highest level of organization of sociality)

Question 4

DEFINE prisoner’s dilemma

Answer 4

a metaphor for the obstacles in the way of cooperation
to either stay silent (and cooperate) or defect against (and be selfish)

Question 5

EXPLAIN prisoner’s dilemma

Answer 5

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

Question 6

What are payoffs in the prisoner’s dilemma equivalent to in real systems

Answer 6

evolutionary fitness, however difficult to measure payoffs in real life

Question 7

Results of prisoner’s dilemma

Answer 7

1. always better to defect rather than cooperate (T>R and P>S)
2. yet everyone would be better off under mutual cooperation than mutual defection (R>P)

Question 8

Five rules for the evolution of cooperation:

Answer 8

1. Kin selection
2. direct reciprocity
3. indirect reciprocity
4. network reciprocity
5. group selection

Question 9

Explain kin selection as evolution for cooperation and example

Answer 9

where individuals forgo their own reproduction to assist with reproduction of a close relative
ex. parental care

Question 10

what equation of kin selection anticipates the drive of evolution of cooperation

Answer 10

r>c/b
r=coefficient of relatedness
c=cost of cooperation to donor of cooperative behaviour
b = benefit of cooperative behaviour to recipient

Question 11

Explain direct reciprocity as evolution for cooperation

Answer 11

where individuals help those that have helped them, if interactions are repeated it is possible for cooperation to emerge

Question 12

Example and equation of direct reciprocity

Answer 12

w>c/b
w = probability of another encounter
ex. reciprocal food sharing in bats

Question 13

Example tit-for-tat strategy in direct reciprocity

Answer 13

in repeated encounters, TFT always cooperates at first, then if others cooperate then also, but if they defect then they will also defect.

Question 14

the 4 traits of the strategies that caused for the highest fitness payoffs in direct reciprocity

Answer 14

1. nice (cooperate first)
2. retaliatory (if defect so will they)
3. forgiving (will forgive if coop after defect)
4. clear

Question 15

Explain indirect reciprocity as evolution of cooperation

Answer 15

cooperation can evolve in individuals that are more likely to cooperate with individuals who have a deserved reputation for cooperating with others

Question 16

Equation for indirect reciprocity and example

Answer 16

q>c/b
q = probability of knowing someone’s reputation
ex. human cooperation (because of complexity and cognitive apparatus involved)

Question 17

Explain how network reciprocity can cause evolution of cooperation

Answer 17

clusters of cooperators tend to interact with other cooperators, allowing for the evolution and spread of cooperative behaviour

Question 18

Equation and example of network reciprocity for evolution of cooperation

Answer 18

k<b/c
k=average number of neighbours
ex. spatial networks, individuals interact with their immediate neighbours

Question 19

Explain how group selection can cause evolution of cooperation

Answer 19

a controversial, theoretical concept that groups with more defectors might be more likely to go extinct

Question 20

Equation of group selection

Answer 20

1+(n/m)<b/c
n=maximum group size
m=number of groups

Question 21

Why is explaining cooperation such a challenge

Answer 21

because natural selection seems to favour selfish behaviour and is complicated to have cooperation evolve in the face of the strong temptation of defect