Lecture 16 Flashcards
1
Q
Eusociality
A
- Overlapping generations
- Cooperative breeding
2
Q
Social Behavior
A
- Interaction with and responses to other individuals of same species
- Cooperation: behavior that if adopted by two or more individuals, benefit both
- Altruism: Behavior that increases another individuals fitness at a cost to ones own fitness
3
Q
Challenge to theory of evolution by natural selection
A
- Why would individuals take actions that increase the fitness of others at the expense of their own fitness
4
Q
Explanation: Shared direct benefits
A
- Cooperation can generate immediate shared benefits
- Cooperative breeding provides a clear example
- Decrease energy cost, possible injury
- Increase offspring survival
- Both females receive an immediate net benefit if they help each other
5
Q
Game theory: Hawk-Dove Game
A
- Contest between two individuals over obtaining a resource
- R= Reward, C = Cost of fighting
- Dove - Dove: R/2
- Dove - Hawk: R
- Hawk - Dove: 0
- Hawk - Hawk: R/2 - C
- If hawk common, playing dove is best. If dove is common, playing hawk is best
- Fitness of strategies is frequency dependent
6
Q
Reciprocity
A
- Given multiple encounters, it does not pay to be selfish and is instead beneficial to be cooperative
- Examine the possibility using iterated prisoner dilemma
7
Q
Iterated Prisoners Dilemma
A
- Cooperate on first encounter: be nice to start
- Copy your opponents last move thereafter
- Retaliate if partner cheats
- Forgive if partner has cheated in past, but then starts to cooperate
8
Q
Predator Inspection
A
- Two fish approaching a predator can be viewed as iterated prisoner’s dilemma
- At each point in time, individuals can continue towards predator, or hold back
9
Q
Experiment
A
- Fish with cooperating mirror and defecting mirror
- Fish with cooperating mirror swim towards predator
- Fish with defecting mirror stay closer to spawn, does not move toward predator
10
Q
What fraction of genes are shared between a and b
A
- 50% of time, a and b share an allele, so r=1/2
11
Q
Altruism directed toward a random individual
A
- Non altruists do best, expect altruist genes to decrease in frequency
12
Q
Altruism directed toward a random individual
A
- Non altruists do best, expect altruist genes to decrease in frequency
13
Q
Long tailed tits don’t help if there are no relatives around
A
- If given a choice between kin and non-kin in same social group, birds help kin nests more
14
Q
Altruism directed toward a genetic relative
A
- Altruists might do best
15
Q
Hamilton’s rule
A
- c = cost of altruism to actor
- b = benefit of altruism to recipient
- r = genetic coefficient of relatedness
- br > c
- Expect greater altruism to be directed towards closer genetic relatives
16
Q
Fruiting body production in social amoeba
A
- Unicellular amoebae aggregate to form fruiting bodies when resources are scarce
- Cells that form the spores have a chance to disperse
- Cells that form stalk of fruiting bodies die
- Social amoebae discriminate kin from non-kin and co-aggregate more with genetically similar individual
