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.
GGG Ping.
Another good one. Thanks!
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."
PING
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Knowing absolutely nothing whatsoever about paleoanthropology, how much d'ya wanna bet this was precisely the point at which early man harnassed fire?
Other candidates might be: Discovered seed-based plant agriculture, discovered husbandry-based animal agriculture, discovered spoken language, discovered the idea of rudimentary written notations, discovered the spear [probably just a tad early for bows and arrows],...
Or maybe was privy to a little divine intervention?
I see gender bias in this article. It mentions the influence of older WOMEN on society...but fails to mention the men! (Guess the brutes were too busy hunting bison to pass on knowledge at the hearth???)
These (IMO) are the most likely, they already had all the others.
They're just making a value judgement that teaching young mothers how to raise children is more important than teaching sons how to hunt and light their farts on fire.
Precisely chipping flint into arrowhead and spear points, the applied geology of how to find likely sources for flint, fire-starting techniques, the vagueries of animal migrations, how to tell when to expect the next salmon run, how to tell when some huge horned critter is about to charge -- all these branches of knowledge are insignificant compared to the proper way to burp a kid. </sarcasm>
Plus, having a few older guys around to protect the camp while they make more spearpoints and arrowheads would have been useful in reducing infant mortality (as well as women-mortality)
Absolute nonsense. If the average life span had been 25 years, a figure which seems to be way too low, according to the authors the average longevity would then have jumped up to 100.
Anthropology ping!
And the sample is how many?
That information is restricted to the small, privileged subset of people who read the article. :-)
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.
Agree. Probably the start of story-telling or the narrative how-to-survive because this is how grand-pa did it.
In todays society, grandparents are usually not close by. I for one, don't think this is a good idea in the long run. Wonder how it will effect us.
I spent pretty much every weekend with my grandparents when I was a kid. It was a hoot. My kids don't get to have that. I feel bad for them.
Elders, no matter what sex, always benefit society. Even though we now have books and the internet to relay stories to us, it can no way compare to your Grandpa explaining the Russian revolution to you while you are on his knee. That was priceless and shaped me forever.
Crevo implications ping.
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