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The Red Queen hypothesis, also referred to as Red Queen's, Red Queen's race or The Red Queen Effect, is an evolutionary hypothesis which proposes that organisms must constantly adapt, evolve, and proliferate not merely to gain reproductive advantage, but also simply to survive while pitted against ever-evolving opposing organisms in an ever-changing environment, and intends to explain two different phenomena: the constant extinction rates as observed in the paleontological record caused by co-evolution between competing species and the advantage of sexual reproduction (as opposed to asexual reproduction) at the level of individuals.〔Bell, G. (1982). The Masterpiece Of Nature: The Evolution and Genetics of Sexuality. University of California Press, Berkeley, 378 pp.〕 Leigh Van Valen proposed the hypothesis to explain the "Law of Extinction",〔 showing that in many populations the probability of extinction does not depend on the lifetime of this population, instead being constant over millions of years for a given population. This could be explained by the coevolution of species. Indeed, an adaptation in a population of one species (e.g. predators, parasites) may change the natural selection pressure on a population of another species (e.g. prey, hosts), giving rise to an antagonistic coevolution. If this positive feedback occurs reciprocally, a potential dynamic coevolution may result. In another idea, the Red Queen hypothesis is used independently by Hartung 〔. Genome Parliaments and Sex with the Red Queen. In: Alexander, R.D., Tinkle, D. W., Eds. Natural Selection and Social Behavior: Recent Research and New Theory. New York: Chiron Press, 1981, 382-402〕 and Bell to explain the evolution of sex,〔 by John Jaenike to explain the maintenance of sex and W. D. Hamilton to explain the role of sex in response to parasites. In all cases, sexual reproduction confers species variability and a faster generational response to selection by making offspring genetically unique. Sexual species are able to improve their genotype in changing conditions. Consequently co-evolutionary interactions, between host and parasite for example, may select for sexual reproduction in hosts in order to reduce the risk of infection. Oscillations in genotype frequencies are observed between parasites and hosts in an antagonistic coevolutionary way without necessitating changes to the phenotype. ==Etymology== The phenomenon's name is derived from a statement that the Red Queen made to Alice in Lewis Carroll's ''Through the Looking-Glass'' in her explanation of the nature of Looking-Glass Land: Now, ''here'', you see, it takes all the running you can do, to keep in the same place. Van Valen coined the hypothesis “Red Queen” because under this interpretation where species have to “run” or evolve in order to stay in the same place or remain extant. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Red Queen hypothesis」の詳細全文を読む スポンサード リンク
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