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The grandmother hypothesis is a hypothesis to explain the existence of menopause in human life history by identifying the adaptive value of extended kin networking. It builds on the previously postulated "mother hypothesis" which states that as mothers age, the costs of reproducing become greater, and energy devoted to those activities would be better spent helping her offspring in their ...
The Grandmother Hypothesis states that menopause comes about into older women in order to restrict the time of reproduction as a protective mechanism. This would allow women to live longer and increase the amount of care they could provide to their grandchildren , increasing their evolutionary fitness. [ 43 ]
The Grandmother hypothesis suggests that menopause was selected for humans because it promotes the survival of grandchildren. According to this hypothesis, post-reproductive women feed and care for children, adult nursing daughters, and grandchildren whose mothers have weaned them.
Finally, Williams' 1957 paper was the first to outline the "grandmother hypothesis". William's formulation stated that natural selection might select for menopause and post-reproductive life in females (though not explicitly mentioning grandchildren or the inclusive fitness contribution of grand-parenting).
The definition of Mitochondrial Eve is fixed, but the woman in prehistory who fits this definition can change. That is, not only can our knowledge of when and where Mitochondrial Eve lived change due to new discoveries, but the actual Mitochondrial Eve can change. The Mitochondrial Eve can change, when a mother-daughter line comes to an end.
The two theories; non-adaptive, and adaptive, are used to explain the evolution of senescence, which is the decline in reproduction with age. [8] The non-adaptive theory assumes that the evolutionary deterioration of human age occurs as a result of accumulation of deleterious mutations in the germline. [ 8 ]
Hawkes, an expert in human evolution and sociobiology, is the author of several studies on the “grandmother hypothesis,” which asserts that many of the characteristics that distinguish us from our ape ancestors are thanks to the thoughtful care of our mothers' mothers. [4]
Kramer's (see Table 1) comparison of nine populations found that siblings accounted for between 1.1% and 33% of the direct childcare received by a child. [14] Older sisters appear to be more important than brothers for many of the groups in the study with sisters ranging from 5% - 33% and brothers 1.1% - 16.3%.