Tuesday, July 25, 2006

Why do grandmas exist ?

What do language, tool-making and higher-order cognition have in common ? Menopause - that's what ! Apprently none of these traits would have evolved in humans, as they haven't in other primates, if not for this unique human trait !

According to Laurence Shaw, medical director at the London Bridge fertility, Gynaeocology and Genetic center...
menopause begat grandmothers, and grandmothers mean daycare and extra nutrition for demanding human babies
Some excerpts...
Women who are no longer able to have children have more time to babysit and forage for food. Both of these functions are important because at this point in her life, a woman's daughter—who is likely around 17 years old and at the peak of her fertility—is busy giving birth to more children.

"[The grandmother] is investing in the second generation of her own line," Shaw said. "None of the other primates—and certainly none of the great apes—show this consistency."
Although this could also explain some of the problems for women in modern life...

While helpful for hunter-gatherers, this decline in fertility is a hindrance in modern life, Shaw says. Women now often delay childbearing until they are less fertile, and more women live past menopause, becoming more susceptible to health problems like osteoporosis, bowel cancer and Alzheimer's disease.

Paradoxically, Shaw's finding might actually prove beneficial to those wanting to have kids at an older age. Scientists already know that the process of fertility decline is controlled by genes that promote apoptosis, or programmed cell death, which causes a reduction in the number of eggs in a woman's ovaries. Knowing this, scientists might be able to use gene therapy to allow women to conceive naturally later in life, Shaw said.

Well...it seems that hot flashes were the reason why humanity has been able to evolve so much ! Hmmm...somebody up there has a wacky sense of humour !

No comments: