Humans are believed to be the most evolved species on the planet, but a recent study has concluded that humans actually have quite primitive hands compared to the hands of the chimpanzee, our closest cousin on the evolutionary tree.
They analysed the hand-length proportions of humans, as well as living and fossil apes to draw a picture of the evolutionary history, and found the human “thumb-to-digits ratio required little change since the LCA”. It indicates that human hands have changed little since the human-chimp evolutionary split.
A new study, published on Tuesday in the journal Nature Communications, has discovered that human hands could be very similar to those of the last common ancestor of humans and chimpanzees – with chimps displaying even more dexterity. Instead, it’s chimpanzee hands that may have evolved.
We aren’t alone in our primitive state. They measured living and fossilized hands of humans and apes, including early human relatives such as the Ardipithecus Ramidus (which was alive 4.4 million years ago and possessed hands quite similar to modern-day human hands, lending credence to the notion that humans have primitive hands).
There is a widely held assumption among palaeontologists that the last common ancestor (LCA) of humans and apes, an individual whose identity remains uncertain, was a prototype chimp with chimp-like hands.
The team crunched the measurements from all these samples using sophisticated statistical methods created to determine the course of hand evolution over time.
Almécija says that a hand capable of precision grasping was “one of the earliest adaptations” among members of the human line, possibly because it made our ancestors better at gathering a wider variety of foods, and not originally because it made them better toolmakers. In fact, the human hand is largely primitive in nature, rather than the result of selective pressures in the context of stone tool-making.
But the study is not likely to receive a warm welcome from researchers who think the common ancestor of chimps and humans was indeed more chimplike.
“This paper serves as a poster child for what is wrong with a lot of work in paleoanthropology”, she said.
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