Re: How Meat Eating CHanged Us - More On "Dental Chaos"/"Evolution Of Cooking"
From: Curious (andropolous_at_gr.org)
Date: 02/25/05
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Date: Fri, 25 Feb 2005 02:02:58 -0600
something of a stretch I think - hard if not impossble to prove. A better
theory distinguishing gorilla from chimps would rely on differences in basic
biochemistry (including brain chemistry) and subsequent nutritional needs ?
Nutritional needs have evolved for all species however.
And everyone knows chimps eat meat because theyare"killers just like us" -
isnt that how the other theory goes? I say laughing ....
jw
Rich Travsky wrote:
> http://news.nationalgeographic.com/news/2005/02/0218_050218_human_diet.html
>
> Meat-eating has impacted the evolution of the human body, scientists
> reported today at the American Association for the Advancement of
> Science's annual meeting in Washington, D.C.
>
> Our fondness for a juicy steak triggered a number of adaptations over
> countless generations. For instance, our jaws have gotten smaller, and we
> have an improved ability to process cholesterol and fat.
>
> Our taste for meat has also led us into some trouble—our teeth are too
> big for our downsized jaws and most of us need dental work.
>
> "It's really amazing what we know now that we didn't know 15 or 20 years
> ago," said Mark Teaford, a professor at Baltimore's Johns Hopkins
> University. Teaford helped organize a panel discussion on human diet from
> a number of perspectives:
>
> • How did the ability to eat meat shape the evolution of humans?
> • What can we learn about early humans from tooth shape?
>
> Carnivorous humans go back a long way. Stone tools for butchering meat,
> and animal bones with corresponding cut marks on them, first appear in
> the fossil record about 2.5 million years ago.
>
> How Did Meat-Eating Start?
>
> Some early humans may have started eating meat as a way to survive within
> their own ecological niche.
>
> Competition from other species may be a key element of natural selection
> that has molded anatomy and behavior, according to Craig B. Stanford, an
> ecologist at the University of Southern California (USC).
>
> Stanford has spent years visiting the Bwindi Impenetrable Forest National
> Park in Uganda, Africa, studying the relationship between mountain
> gorillas and chimpanzees.
>
> "It's the only forest where mountain gorillas and chimps both live," he
> said. "We're trying to understand the ecological relationship—do they
> compete for food, for nesting sites?"
>
> The key difference between chimps and gorillas ecologically is that chimps
> eat meat and gorillas don't. A total herbivore is able to coexist with an
> omnivore because they have significantly different diets.
>
> "From there we can extrapolate back to what two species of early humans may
> have done vis-à-vis each other two or three million years ago," Stanford
> said.
>
> Better Fat Processors
>
> When humans switched to meat-eating, they triggered a genetic change that
> enabled better processing of fats, said Stanford, who has worked
> extensively with gerontologist Caleb Finch of USC.
>
> "We have an obsession today with fat and cholesterol because we can go to
> the market and stuff ourselves with it," Stanford said. "But as a species
> we are relatively immune to the harmful effects of fat and cholesterol.
> Compared to the great apes, we can handle a diet that's high in fat and
> cholesterol, and the great apes cannot.
> ...
>
> Diet and Teeth
>
> Tool-use no doubt helped early humans in butchering their dinners. But
> there is evidence that the advance to cooking and using knives and forks is
> leading to crooked teeth and facial dwarfing in humans.
>
> Today it's relatively rare for someone to have perfectly straight teeth
> (without having been to the orthodontist). Our wisdom teeth don't have room
> to fit in the jaw and sometimes don't form at all, and the propensity to
> develop gum disease is on the increase.
>
> "Virtually any mammalian jaw in the wild that you look at will be a perfect
> occlusion—a very nice Hollywood-style dentition," said Peter Lucas, the
> author of Dental Functional Morphology and a visiting professor at George
> Washington University in Washington, D.C. "But when it comes to humans, the
> ideal occlusion [the way teeth fit together] is virtually never seen. It's
> really the only body part that regularly needs attention and surgery."
>
> Lucas argues that the mechanical process of chewing, combined with the physical
> properties of foods in the diet, will drive tooth, jaw, and body size,
> particularly in human evolution.
>
> Essentially, by cooking our food, thereby making it softer, we no longer need
> teeth big enough to chow down on really tough particles. By using knives and
> forks to cut food into smaller pieces, we no longer need a large enough jaw to
> cram in big hunks of food.
> ...
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