Mathematicians found, when the first grandmother
MOSCOW, 21 Feb — RIA Novosti. Grandma first appeared in humans only after our ancestors got a mind and memory, as their existence was not advantageous from an evolutionary point of view, say scientists in an article published in the journal PLOS Computational Biology.
“Mind and memory allow us to collect and develop useful skills and experience throughout life. This skills and experience helped our ancestors to forage for food and other resources, and cessation of reproduction allowed them to redirect some of these resources to help their children and grandchildren, increasing their fertility and probability of survival of their offspring,” explains Karla Aime (Aime Carla) from the University of Montpellier (France).
It is believed that most of the animals retains the ability to reproduce throughout their adult life. Barren elderly individuals are not good for the population, which is why the lifespan of most mammals is limited to the timing of their fertility. There are exceptions to this rule — first and foremost among these mammals is the man and whales-orcas.
At the moment, anthropologists have explained the existence of the elderly the so-called “grandmother hypothesis”. In accordance with this theory, older women cease to breed, for evolutionary reasons — helping their daughters to raise and educate children, grandmother thus increasing the chances of further transmission of their genes. Anthropologists have found confirmation of this theory in populations of Africans stuck in a primitive society.
This theory, as noted by Amy, describes possible causes, and the pros from the appearance of grandmothers and menopause, but you can’t understand, when they appeared, and does not explain the fact that here was cause and what was the result.
To answer this question, Amy and her colleagues created a computer model of several tribes of ancient people, females which had different versions of the “grandmother hypothesis” and other strategies of reproduction and care of offspring.
Watching the growth of these groups of proto-humans, the researchers watched how fast have grown or decreased their population and how different factors, including life expectancy, time of menopause, the chances of dying during childbirth and other physiological characteristics that affect female fertility and the probability of survival of their offspring.