L12: Social Adaptation
Kin selection: Greenbeard effect
If a single gene encodes (i) a detectable marker & (ii) helpfulness towards bearers of the marker, then the gene ensures that it is helping copies of itself. This clarifies that genetic relatedness is only for the trait in question, not for the whole genome
Kin selection
Kin selection is the evolutionary strategy that favours the reproductive success of an organism's relatives, even at a cost to the organism's own survival and reproduction. Kin altruism is altruistic behaviour whose evolution is driven by kin selection. Kin selection is an instance of inclusive fitness, which combines the number of offspring produced with the number an individual can ensure the production of by supporting others, such as siblings.
Kin selection: Limited dispersal
Limited dispersal from place of birth means that even indiscriminate helping primarily benefits relatives. Probably a very general mechanism for kin selection, e.g. microbial cooperation
Inclusive Fitness Theory
Natural selection leads organism to appear design to maximise their ___. they should appear to value the reproductive success of their genetic relatives. a model for the evolution of social behaviors, first set forward by W. D. Hamilton in 1963 and 1964. Instead of a trait's frequency increase being thought of only via its average effects on an organism's direct reproduction, Hamilton argued that its average effects on indirect reproduction, via identical copies of the trait in other individuals, also need to be taken into account. if -c +br < 0 the the behaviour is disfavoured by natural selection.
Relatedness
• Full siblings genetically related by 50% • But human and chimp DNA is 99% similar! • Relatedness measures genetic similarity relative to the population average for the trait in question
Kin selection: Kin recognition
• Recognizing and behaving differently towards kin also ensures helping primarily benefits relatives • Requires special discrimination abilities, so will apply to only certain taxa
