The concept that advanced humans and knuckle-dragging apes is evolving.
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In fact, human hands are likely more similar to those of the last common ancestor we and chimps shared millions of years ago.
These results support the hypothesis that the long thumb to fingers ratio of the human hand was acquired convergently with other highly dexterous anthropoids.
PARIS: Strong fists for defending ourselves and opposable thumbs for work as fine as threading a needle – hand specialisation is widely believed to have given humans a major evolutionary advantage.
Newswise – Today, Nature is publishing a paper “The evolution of human and ape hand proportions”, a study that discovers that human hands may be more primitive than chimp’s. A new study reveals that human hands are actually less developed in terms of evolution than a chimp’s hand.
In fact, it is the hands of chimps and orangutans that changed most since they split off to form new branches of the hominid family tree – developing longer fingers, compared to the thumb, for swinging on tree branches.
They found that early human relatives like Ardipithecus ramidus, which lived 4.4 million years ago, had hands similar to our own. Gorilla hands are also very similar to those of the extinct creature that links man and ape. This allowed them to get a better understanding at the process of hand evolution over time.
These findings suggest human hand structures are largely primitive rather than being the result of selective pressures from stone toolmaking.
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The findings challenge the idea that a chimp-like hand was the starting point of evolutionary progress towards the modern human hand. “It’s good to see that some of the implications of Ardi”-that the common ancestor of chimps and humans was not chimplike-“are being noticed”, adds Owen Lovejoy, an anatomist at Kent State University in Ohio and member of the team that studied this early member of the human line””. Zihlman argues that the hands alone provide researchers with only a very limited view of what the common ancestor was like.
