April 13, 2006
Fossil Find Strengthens Sequence of Human Evolution
Location of the discovery explains an early separation
of hominid species
By SETH BORENSTEIN
WASHINGTON - Fossils have
long provided snapshots of the human family tree,
but a new find in Africa gives scientists a kind of
mini home movie showing man's primal development.
4.2-million-year-old fossil is from the same human
ancestral hot spot in Ethiopia as remains from seven
other human-like species, scientists can now fill in
the gaps for the most complete evolutionary chain so
"We just found the chain of
evolution, the continuity through time," said
Ethiopian anthropologist Berhane Asfaw, co-author of
the study being reported today in the journal
Nature. "One form evolved to another. This is
evidence of evolution in one place through time."
<>The species, Australopithecus anamensis,
is not new, but its location is what helps explain
the giant leap from one early phase of human-like
development to the next, scientists say. All eight
species were found in a region called the Middle
"It's like 12 frames of a
home movie, but a home movie covering 6 million
years," said study lead author Tim White,
co-director of Human Evolution Research Center at
University of California at Berkeley. Fossils in the
region cover three major phases of human
"The key here is the
sequences," White said. "It's about a mile thickness
of rocks in the Middle Awash, and in it we can see
all three phases of human evolution."
Modern man belongs to the
genus Homo, a subgroup
in the family of hominids. What evolved into Homo
was likely the genus Australopithecus, which includes the famed 3.2
million-year-old "Lucy" fossil found three decades ago.
A key candidate for the genus
that evolved into Australopithecus is called
finding is important in bridging — but not
completely — the gap between Australopithecus and
In 1994, a 4.4
million-year-old partial skeleton of the species
Ardipithecus ramidus —
the most recent Ardipithecus species — was found
about six miles from the latest discovery.
"This appears to be the link
between Australopithecus and Ardipithecus as two
different species," White said.
The major noticeable
difference between the phases of man can be seen in
Australopithecus' bigger chewing teeth to eat harder
food, he said.
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