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The Patriarch Hypothesis is a theory to explain the occurrence of menopause in human females and how a long post-fertile period (up to one third of a females life-span)〔Harman, S.M. and Talbert, G.B. (1985). Reproductive aging. In: Handbook of the Biology of Aging, by C. E. Finch and L. Hayflick (eds). pp 457-510. Van Nostrand Reinhold.〕 could confer an evolutionary advantage. It is an alternative theory to the grandmother hypothesis which tends to ignore male benefits of continued spermatogenesis and their roles in assistance. The patriarch hypothesis incorporates these neglected areas. It suggests selection pressure on male longevity extended the female lifespan; whose adjustment of life history has been constrained by the size of the ovaries – resulting in human females surviving beyond the age at which they can reproduce. With an extension of the post-reproductive female life stage, they could enhance their inclusive fitness by giving kin assistance. This way, with no choice in the timing of fertility termination, females are optimising an essentially bad situation. ''See also Grandmother hypothesis'' ==The Patriarch Hypothesis== (Frank Marlowe ) first put forward the patriarch hypothesis.〔Marlowe, F. (1999). Male care and mating effort among Hadza foragers. Behavioral Ecology and Sociobiology. 46(1): 57-64.〕 He postulates that if women survive beyond an age at which they can reproduce and men continue spermatogenesis, then old males stand to benefit greatly if they can copulate with younger females. It is theorised that increased use of tools and weapons compensates for the decline in natural fighting ability with age.〔Marlowe, F. (2000). The Patriarch Hypothesis: An Alternative Explanation of Menopause. Human Nature. 11(1): 27-42.〕 This serves to produce a more stable male hierarchy, where attainment of high social status and reproductive access is less reliant on physical strength. With such a scenario older males are able to retain a competitive ability with younger males, thereby asserting a selection pressure on extending longevity in males that could retain social status. Higher ranking males may also be a more attractive mate choice. One mechanism that could extend the lifespan is delaying the age at maturity. Offspring with a slower life history would exhibit a protracted period of dependence. If depletion of oocytes occurs at age 50, females should selectively counter this as it reduces their fecundity. Recruitment of help from kin and husbands may compensate by enabling females to reduce birth intervals by weaning offspring at an earlier age. In addition, by passing on longevity to her sons, a female would stand to gain inclusive fitness.〔 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「Patriarch hypothesis」の詳細全文を読む スポンサード リンク
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