7 Million Year Old Practice Put Our Ancestors On The Way To Humanity, New Study Says

Researchers examined a femur and two bones from the ulna arm of Sahelanthropus tchadensis, one of the earliest known human ancestors, and found signs that they walked on two feet – also known as bipedalism, according to a new study published Wednesday in Nature.

“Our earliest known representatives practiced bipedalism (on the ground and on trees),” said study author Franck Guy, a researcher at the University of Poitiers in France. The remains of ancient beings show that bipedalism arose soon after chimpanzees and human ancestors diverged on their evolutionary paths, he added.

There is even more to discover in these fossils. Their characteristics show that Sahelanthropus tchadensis also retained the ability to climb trees proficiently, according to the study.

These ancestors were hominins, or species more closely related to humans than chimpanzees, and they mark an early stage in our evolutionary divergence, said Daniel Lieberman, professor of human evolutionary biology and paleoanthropologist at Harvard University. Lieberman was not involved in the study.

Bipedalism in these ancestors is not exactly a surprise. The arm and leg bones analyzed in this study were found in Chad in 2001 alongside a nearly complete skull, according to the study. It’s unclear whether they come from the same individual, however, said study author Guillaume Daver, an assistant professor of paleontology at the University of Poitiers.

The skull showed a downward-pointing point where the head and spinal cord come together — a feature that would make it much more difficult to crawl, Lieberman said.

The new analysis from members of this discovery provides even more evidence that hominins traveled on two legs as they roamed the Earth around 7 million years ago, he added.

“It’s a glimpse of what put the human lineage on a separate evolutionary path from our ape cousins,” Lieberman said. Although recent discoveries confirm what early studies already suggested, fossils from this era are rare, so each find is an important piece of evidence, he added.

And the new study “makes it pretty unlikely that the common ancestor we share with chimps was chimpanzee-like,” Guy said.

This image shows the thickness variation map for the femurs of (from left to right) Sahelanthropus, an extant human, a chimpanzee, and a gorilla (in posterior view).

Bipedalism set the fire

Bipedalism was hugely important to our evolution, but it didn’t make much sense to our ancestors, Lieberman said.

Walking on two legs makes an animal slower, more unsteady and more at risk of back pain, which is not helpful for survival, he added.

“There must have been a really big upside,” Lieberman said. Scientists have a hypothesis about what it could have been.

Our common ancestor with monkeys looked a lot like a chimpanzee, and we know they need a lot of energy to walk — twice as much as humans when you adjust to body size, Lieberman said.

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When human and chimpanzee evolutionary paths diverged, Earth’s climate changed and Africa’s rainforests fell apart, so our ancestors had to travel farther to find food, he said. he declares. The hypothesis is that walking on two legs gave them more energy to travel.

“What really started us on this different evolutionary path was that we were bipedal, or we walked on two legs,” Lieberman said. “It really helps us understand the origins of mankind.”

There are many things that define us as humans, like language, tools and fire, he said. And in the 1870s, Charles Darwin — without any of the evidence we now have — guessed that walking on two legs was the spark that started it all, Lieberman said.

And we can now see that bipedalism was a big ape differentiator and helped free our hands to develop tools, Lieberman said.

“We agreed with Darwin,” he said. “That’s pretty cool.”

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