Very early evidence for modern man
- From: Lance <LanceGary@xxxxxxxxx>
- Date: Thu, 18 Oct 2007 13:17:02 -0000
Earliest evidence for modern human behavior found in South African
cave
Evidence of early humans living on the coast in South Africa,
harvesting
food from the sea, employing complex small stone tools and using red
pigments in symbolic behavior 164,000 years ago, far earlier than
previously documented, is being published in the Oct. 18 issue of the
journal Nature.
The international team of researchers reporting the findings includes
Tom Minichillo, an affiliate assistant professor of anthropology at
the
University Washington and the King County Department of Transportation
archaeologist.
"Our findings show that at 164,000 years ago in coastal South Africa
humans expanded their diet to include shellfish and other marine
resources, perhaps as a response to harsh environmental conditions,"
said Curtis Marean, a paleoanthropologist with the Institute of Human
Origins at Arizona State University who headed the research team "This
is the earliest dated observation of this behavior."
Further, the researchers report that also occurring with this diet
expansion is a very early use of pigment, likely for symbolic
behavior,
as well as the use of bladelet stone tool technology, previously
dating
to 70,000 years ago.
These new findings not only move back the timeline for the evolution
of
modern humans, they show that lifestyles focused on coastal habitats
and
resources may have been crucial to the evolution and survival of these
early humans.
After decades of debate, paleoanthropologists now agree the genetic
and
fossil evidence suggests that the modern human species, Homo sapiens,
evolved in Africa between 100,000 and 200,000 years ago. Yet,
archaeological sites during that time period are rare in Africa.
However, the researchers found a rich site about 250 miles east of
Cape
Town, South Africa, near the town of Mossel Bay along the Indian
Ocean.
The Middle Stone Age, dated between 35,000 and 300,000 years ago, is
the
technological stage when anatomically modern humans emerged in Africa,
along with modern cognitive behavior. When, however, within that stage
modern human behavior arose is currently debated, added Marean, who is
a
professor of human evolution and social change.
The material found in one of the caves at Pinnacle Point is beyond the
range of radiocarbon dating. But firm dates were obtained using two
advanced and independent techniques -- uranium series that dated
speleothem, the material of stalagmites, and optically stimulated
luminescence that dates the last time individual grains of sand were
exposed to light.
"Generally speaking, coastal areas were of no use to early humans --
unless they knew how to use the sea as a food source," said Marean.
"For
millions of years, our earliest hunter-gatherer relatives only ate
terrestrial plants and animals. Shellfish was one of the last
additions
to the human diet before domesticated plants and animals were
introduced."
Before, the earliest evidence for human use of marine resources and
coastal habitats was dated about 125,000 years ago. "Our research
shows
that humans started doing this at least 40,000 years earlier. This
could
have very well been a response to the extreme environmental conditions
they were experiencing," he said.
The researchers also found a variety of stone tools including what
archaeologists call bladelets -- tiny blades fashioned from quartzite
and quartz. They are smaller than the width of the nail on a human
little finger and a little longer than one inch. The bladelets could
be
attached to the end of a stick to form a point for a spear, lined up
like barbs on a dart or used independently as a cutting tool like a
pen
knife, according to Minichillo.
"These tools were not made accidentally, because we found so many of
them, as well as the cores from which they were manufactured. This
supports the idea that the tool kits of the earliest Homo sapiens had
more variety than they are traditionally given credit for," said
Minichillo. "Ordinarily older things, such as tools, are bigger than
newer ones. Bladelets are the first small objects recognizable as a
tool.
The researchers also found evidence that the people occupying the cave
were using pigments, especially red ochre, in ways that appear to be
symbolic. Archaeologists view symbolic behavior as one of the clues
that
modern language may have been present. The modified pigments are the
earliest securely dated and published evidence for pigment use.
"Coastlines generally make great migration routes," Marean said.
"Knowing how to exploit the sea for food meant these early humans
could
now use coastlines as productive home ranges and move long distances."
Results reporting early use of coastlines are especially significant
to
scientists interested in the migration of humans out of Africa.
Physical
evidence that this coastal population was practicing modern human
behavior is particularly important to geneticists and physical
anthropologists seeking to identify the ancestral population for
modern
humans.
"This evidence shows that Africa, and particularly southern Africa,
was
precocious in the development of modern human biology and behavior. We
believe that on the far southern shore of Africa there was a small
population of modern humans who struggled through the glacial period
125,000 to 195,000 years ago using shellfish and advanced
technologies,
and symbolism was important to their social relations. It is possible
that this population could be the progenitor population for all modern
humans," Marean said.
"The oldest view that early Homo sapiens didn't have full modern
behavior was built largely on an absence of evidence," added
Minichillo.
"Now we have data that doesn't match that idea. It may be that early
modern humans had that ability when they first appeared on the
landscape."
Source: University of Washington
http://www.physorg.com/news111847910.html
.
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