A 4.4-million year old fossil, discovered in Africa has opened a window onto humans' "early evolutionary steps," according to the group of scientists responsible for the find. Ray Suarez reports.
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Science has long taught that humans evolved from a species similar to modern-day chimps and gorillas, but researchers announced new findings today that call that belief into question, suggesting the line of evolution may have been more complex.
The research was published in the journal Science and chronicled in a new documentary produced by the Discovery Channel. Scientists say the species lived more than 4 million years ago and could be a common ancestor for humans and chimps.
It was nicknamed Ardi, short for Ardipithecus ramidus. The finding was of a female fossil, thought to be 4 feet tall and weighing about 120 pounds.
The story of the discovery began in 1992 at a site in Ethiopia's Afar rift, about 140 miles northeast of Addis Ababa. At the time, teeth and other small fragments of a skeleton were discovered. It would take more than 15 years of work — digging, reconstruction, and computer simulation — to confirm that an earlier ancestor had been discovered.
C. OWEN LOVEJOY, Kent State University:
It took years as a consequence to look at all the details of things like the wrist bone to figure it all out, because we've never seen anything like this before.
Until today, anthropologists had thought Lucy, a skeleton dating back more than 3 million years, was the oldest ancestor known to humans. She, too, was discovered in Ethiopia.
But at a press conference today, scientists said Ardi came first. C. Owen Lovejoy was part of the team.
C. OWEN LOVEJOY:
If you were to ask someone on the street today, "What did an early ancestor of humans look like?" they would probably say, well, it would look like Lucy and, before that, it would look like a chimpanzee. What the fossils that are being described in Science today will tell you is that both of those conclusions are very incorrect.
As shown in this animation done for the Discovery Channel, Ardi was an agile tree climber, like chimps and apes, but she was more inclined to walk upright on two legs.