Or found the obelisk?
Posted on 07/05/2004 6:26:07 PM PDT by blam
Teeth show how society was shaped by old age
By Roger Highfield, Science Editor
(Filed: 06/07/2004)
The lifespan of our ancestors made a dramatic leap 32,000 years ago, allowing people to grow older and wiser, according to a study of hundreds of ancient teeth that is published today.
The wear on the teeth suggest that longevity more than quadrupled at that time, a jump that may have been the key factor that shaped modern civilisation. Before then lifespan had increased only steadily.
Lifespan extended dramatically in the early Upper Palaeolithic Period, around 30,000bc, when Homo sapiens - modern man - was becoming established in Europe. The American team believes there had to be a distinct evolutionary advantage to large numbers of people growing older, which in turn enabled still more of our ancestors to live longer.
Despite more disease and disability, longer survival would have increased the number of years to have children and encouraged social relationships and kinship bonds.
And it would have encouraged the passing of information from old and experienced individuals to younger generations, the "grandmother hypothesis"- grandmothers are useful because of the knowledge they hand on to their reproductive-age daughters, and their daughters' children.
Together, these factors could have promoted the expansion of populations, creating social pressures that led to the growth of trade networks, increased mobility, and more complex systems of co-operation and competition.
One of the authors, anthropologist Dr Rachel Caspari, from the University of Michigan at Ann Arbor, said: "There has been a lot of speculation about what gave modern humans their evolutionary advantage. This research provides a simple explanation for which there is now concrete evidence: modern humans were older and wiser.
"It is easier to study the consequences than it is to speculate about the causes," she said. However, she believes the surge in numbers "may reflect a positive feedback process, where small increases led to advantages that precipitated bigger increases".
The findings, published today by Dr Caspari and Dr Sang-Hee Lee in the Proceedings of the National Academy of Sciences, were based on a comparison of more than 750 tooth fossils from successive time periods.
In the study, they defined "old" to be at least double the age of reproductive maturation, which is also the time when the third molars typically erupt. Thus, even if the age of reproductive maturation varied, if it were 15, then age 30 would be the age at which one could theoretically first become a grandmother.
The specimens examined came from later australopithecines - a primitive, ape-like human - early and middle Pleistocene era Homo species, Neanderthals from Europe and Asia, and post-Neanderthal Early Upper Palaeolithic Europeans.
By calculating the ratio of old-to-young individuals in the samples, the scientists found that the number of surviving older people increased throughout human evolution.
Their numbers soared up to fivefold in the Upper Palaeolithic group, a leap that was so surprising that the team at first questioned its own results.
Minimal, really. But Junior likes pings for the archives.
Or found the obelisk?
Nahhh. It was the beads.
'Preciates it.
I suspected a rather small sample and 750 tooth fossils from successive time periods is small.
Society's still being shaped by old age. The older I get the more my "society" changes.
:-p
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The Barakamites see no value to the elderly! Throw'em under the bus!!!
Yes, it seems unlikely to me too. I'm going to guess that what they meant to say was that the percentage of humans who lived to be old enough to be grandparents quadrupled (from some presumably small number).
I posted this article six years ago.
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