Turkish Journal of Geriatrics 2005 , Vol 8, Issue 4
Ankara Üniversitesi Tıp Fakültesi Cebeci Hastanesi, ANKARA There is growing interest in the topic of aging, and accordingly in the search for the evolution of human longevity and the prolongation of post-reproductive lifespan. Without doubt, one of the reasons for this interest is the absolute and relative increase of elderly people in societies. This study reviews and critically evaluates the findings of studies which have focused on the evolution of human life history and senescence. Some authors attribute the increasing human lifespan and the long post-reproductive period to expansion in the cranial capacity. They assume that increased brain size enabled the early hominids to improve their overall quality of diet by hunting and foraging more efficiently; that it decreased ecological mortality rate on the other; and that all these factors produced human longevity. Another group of researchers defend the “grandmother hypothesis,” which claims that older women who had ceased productive activity gained evolutionary advantage through their investment in reproductive-aged daughters and their offspring. According to this hypothesis, aging is a byproduct of grandmothering. Although the supporters of both views believe that the increase in lifespan occurred with the appearance of the genus Homo, the findings from human fossils show that senescence became common relatively late in human evolution, at the beginning of the Upper Paleolithic period. Keywords : Human evolution, Senescence, Brain volume, Grandmother hypothesis, Human life history, Biocultural evolution