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Date: | Fri, 13 Aug 1999 08:19:24 -0400 |
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I found this item from http://abcnews.go.com/sections/living/ interesting.
Humans have been cooking their food for a long time.
By 1.9 million years ago, when Homo erectus
appeared, teeth became smaller and jawbones
less robust. Females got bigger-closer in size
to males. Brains and bodies both grew.
Laden and Wrangham said the changes
occurred because the pre-humans had
discovered fire and learned how to make roots
and other vegetables easier to eat and more
nutritious.
While some anthropologists argue it was
because meat entered the diet, L
aden and a
team of anthropologists, nutritionists and
primatologists argued otherwise.
"However you put meat in doesn't fit in," he
said.
Some Meat Consumed
Laden pointed to recent studies that
indicated pre-humans ate some meat-probably
scavenged from carcasses-more than 2.5
million years ago. But their bodies did not
change until much later.
"At 2 million years we see no change in the
distribution of (animal) bones (at pre-human
sites) and we don't see meat as being
high-energy food source. It has to be (a)
high-energy food source to explain this doubling
of body size," he said.
I
n addition, evidence is building that humans
started to use fire just at the time their bodies
changed. Meat is just as nutritious whether it is
raw or cooked, but plant food is not.
"(Cooking) also makes a lot of things less
toxic and more chewable. If you are an ape with
fire, there is a much longer list of foods you
can eat," Laden said.
"We strongly suspect hominids began using
fire about 1.9 million years ago, when Homo
erectus appeared," he added.
Fire for Half Million Years
He said colleagues working in Kenya have
recently contacted his team and said they have
evidence that humans were controlling fire that
long ago. The most rece
nt accepted evidence
puts fire use at just 200,000 to 500,000 years
ago.
Cathryn
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