Kin Selection Flashcards
Eusocial insects on bottom of slide 3
Eusocial insects on bottom of slide 3
Direct fitness (# of offspring) plus equivalents gained through support (direct fitness + anything from close family members)
Inclusive fitness
A strategy that is the best response, given other participants responses. Whatever individual displays the best strategy cant be beaten
Nash equilibrium
BATS EXAMPLE ON 5
BATS EXAMPLE ON 5
Why is acting altruistically unstable?
If one member of the group decides not too, they are now the highest fitness and everyone else is left behind
Fitness when not helping - fitness when helping
Cost of helping
When do individuals act altruistically?
When c < r x b
Cost is less than relatedness multiplied by benefit to altruists relatives
Why does cooperative breeding not make sense from a Darwinian evolution standpoint?
Individuals should not act selfishly
When individuals cooperate in the care of young. There is reproductive division of labor, with sterile (or nearly sterile) workers assisting fecund individuals (a specific type of cooperative breeding)
Eusocial species
An action that reduces an individuals own fitness while increasing the fitness of another individual (never actually seen anywhere in biology)
Altruism
How are sisters related in a diploid case?
50% related
A strategy that, if established, cant be invaded by a rare mutant using an alternative strategy (a special case of Nash equilibrium)
Evolutionarily stable strategy (ESS)
Selection acting on individuals related through recent, common descent (direct offspring)
Kin selection
Fitness = direct fitness + (r x fitness effect on relatives)
or
Fitness = direct fitness + indirect fitness
Inclusive fitness (Hamilton’s rule)
Who are females more closely related to in a haplodiploid case?
They are more closely related to their sisters than their daughters
How does an organism become haplodiploid?
Females develop from fertilized eggs (diploid, 2N) and males develop from unfertilized eggs (haploid, N)
Fitness if selfish
w
The probability that two individuals share a particular allele (how related two individuals are)
Relatedness, r
What two things does the evolution of altruism require?
- heritable variation in altruism
2. positive association between altruists
CALCULATING RELATEDNESS FOR DIPLOID AND HAPLODIPLOID
CALCULATING RELATEDNESS FOR DIPLOID AND HAPLODIPLOID
What does kin selection depend on?
Relatedness, r
How are sisters related in a haplodiploid case?
They are 75% related
What does relatedness data show about individuals who act altruistically?
The more closely related individuals are, the more likely they are to be altruistic
What are the two reasons cooperative behavior exists?
- selection at the level of the family (kin selection)
2. reciprocity (cooperate to get the favor returned)
What are many eusocial insects?
Haplodiploid
Fitness when helped - fitness when not helped
Benefit of being helped
Altruism is rewarded with altruism and defection is punished by defection
Reciprocal altruism
KIN SELECTION SUMMARY IN MIDDLE OF 4
KIN SELECTION SUMMARY IN MIDDLE OF 4
How can altruism evolve among relatives?
Altruism will benefit other altruists so there is a positive association between altruists
Fitness if altruist
w - c + (r x b)
When some members forego reproduction while in the group. May risk death by defending the colony. Devote energies toward rearing of young of others (helping at the nest)
Cooperatively breeding organisms
When is needed for reciprocity to work?
Individuals need to be able to recognize specific individuals in their species
