The Selfish Gene Flashcards
Kin selection
mode of selection in which genes spread because of their fitness effects on other bodies likely to be carrying the identical gene
Developed by W. D. Hamilton to explain the evolution of altruistic behavior
Reciprocal altruism
a situation in which altruism is extended only to other altruists
Kin Selection (Direct Route)
a gene that somehow makes its surrounding body more fit is more likely to be copied than one that does not
The fundamental problem with altruism is that it makes the body less fit
Kin Selection (Indirect route)
a gene that induces altruism in one individual and aims the benefits of that altruism at another individual who (by common ancestry) carries the same gene.
Hamilton’s Rule (Kin Selection)
In any altruistic encounter there is
An altruist who pays a cost
A recipient who gets a benefit
Variables
C = the size of the cost
B = the size of the benefit
A kin-selected gene spreads because it confers benefits on other carriers of the same gene
We cannot say for certain whether two people carry the same gene, but we can express the probability that they carry the same gene
Variables
R = the coefficient of relatedness
This number is somewhere between 1 and 0
Hamilton’s Rule - Continued
A gene will spread if it induces altruistic behavior when rb>c
Kin-selected genes induce altruism whenever the benefit devalued by the degree of relatedness outweighs the cost.
When rb>c
Reciprocity
system in which altruism is extended only to other altruists
Requires discrimination against cheaters
Developed by Robert Trivers
The key to altruism is reciprocity
Behave altruistically to other altruists
Withhold altruism with those who do not pay you back
Cheater
an individual who accepts benefits (altruism) but does not reciprocate
Tit-for-Tat
begins by cooperating on the first move and thereafter simply copies the previous move of the other player
