A Discussion of the Grandmother Hypothesis

We humans are longer-lived than our near primate cousins, and this is a comparatively recent development in evolutionary time. It is thought that this longevity arises from our greater intelligence and culture. When grandparents can contribute to the reproductive success of grandchildren, there is a selection pressure favoring mechanisms that allow for individual survival to older ages than would otherwise be the case. Chimpanzees do not have sufficient intelligence and culture for grandparents to greatly influence the success of their grandchildren, natural selection does not operate as strongly on the shape of later life, and thus chimpanzees are not as long-lived as humans. According to long-standing canon in evolutionary biology, natural selection is cruelly selfish, favoring traits that help promote reproductive success. However, by the age fertility ceases, the story goes that selection becomes blind to what happens to our bodies. After the age of menopause, our cells are more vulnerable to mutations. In the vast majority of animals, this usually means that death follows shortly after fertility ends. Which puts humans (and some species of whale) in a unique club: animals that continue to live long after their reproductive lives end. How is it that we can live decades in selection's shadow? In most animals, including chimpanzees - our closest primate brethren - this link between fertility and longevity is very pronounced, where survival drops in sync with the ab...
Source: Fight Aging! - Category: Research Authors: Tags: Daily News Source Type: blogs