User:Crudiant/sandbox1

Kinselektion (af engelsk "kin" '  slægt) er en evolutionære strategi, der fremmer reproduktiv succes for en organismes slægtninge, selv til en pris på organismens egen overlevelse og reproduktion. 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 produce by supporting others, such as siblings.

Charles Darwin diskuterede begrebet kinselektion i sin 1859 bog,The Origin of Species, where he reflected on the puzzle of sterile social insects, such as honey bees, which leave reproduction to their sisters, arguing that a selection benefit to related organisms (the same "stock") would allow the evolution of a trait that confers the benefit but destroys an individual at the same time. R.A. Fisher in 1930 and J.B.S. Haldane in 1932 set out the mathematics of kin selection, with Haldane famously joking that he would willingly die for two brothers or eight cousins. In 1964, W.D. Hamilton popularised the concept and the major advance in the mathematical treatment of the phenomenon by George R. Price which has become known as "Hamilton's rule". In the same year John Maynard Smith used the actual term kin selection for the first time.

According to Hamilton's rule, kin selection causes genes to increase in frequency when the genetic relatedness of a recipient to an actor multiplied by the benefit to the recipient is greater than the reproductive cost to the actor. The rule is difficult to test but a study of red squirrels in 2010 found that adoption of orphans by surrogate mothers in the wild occurred only when the conditions of Hamilton's rule were met. Hamilton proposed two mechanisms for kin selection: kin recognition, where individuals are able to identify their relatives, and viscous populations, where dispersal is rare enough for populations to be closely related. The viscous population mechanism makes kin selection and social cooperation possible in the absence of kin recognition. Nurture kinship, the treatment of individuals as kin when they live together, is sufficient for kin selection, given reasonable assumptions about dispersal rates. Kin selection is not the same thing as group selection, where natural selection acts on the group as a whole.

In humans, altruism is more likely and on a larger scale with kin than with unrelated individuals; for example, humans give presents according to how closely related they are to the recipient. In other species, vervet monkeys use allomothering, where related females such as older sisters or grandmothers often care for young, according to their relatedness. The social shrimp Synalpheus regalis protects juveniles within highly related colonies.

Historie
Charles Darwin var den første til at diskutere begrebet kinselektion. In The Origin of Species, he wrote clearly about the conundrum represented by altruistic sterile social insects that

"This difficulty, though appearing insuperable, is lessened, or, as I believe, disappears, when it is remembered that selection may be applied to the family, as well as to the individual, and may thus gain the desired end. Breeders of cattle wish the flesh and fat to be well marbled together. An animal thus characterised has been slaughtered, but the breeder has gone with confidence to the same stock and has succeeded."

- Darwin

In this passage "the family" and "stock" stand for a kin group. These passages and others by Darwin about "kin selection" are highlighted in D.J. Futuyma's textbook of reference Evolutionary Biology and in E. O. Wilson's Sociobiology.

Yderligere læsning


Category:Selection Category:Evolutionary biology