The Human Thumb Just Becomes 500,000 Years Old


Researchers studying the fossil hands of 2-million-year-old hominins have concluded that human thumbs were again the same as our thumbs today. It was the “dexterity” introduced by the human thumb that enabled us to eliminate all other species on Earth.

Until now, the ancient origins of the human thumb and dexterity, have always been tightly closed archaeological mysteries. By 3D modeling the extent of muscle movement in the ancient, fossilized thumb, a team of German researchers has concluded that it was around 2 million years ago that our early human ancient ancestors first developed this important survival tool.

The Human Thumb: All the Better to Squeeze With!

New Study Was published in the magazine Current biology By a team of paleoanthropologists from Tübingen University. Researchers digitized ancient hominin fossil thumb bones, including those Homo sapiens (Us), a project fraught with complications.

The main problem facing the research team was that the fossils did not preserve muscle and this is known as “speculation”.

To help them accurately analyze ancient human thumbs, the team of researchers first looked at hand bone samples from two early modern humans and four Neanderthals, all alive and dead during the last 100,000 years.

Summary of the analytical stages of the study: (a) Model preparation and perception of human or chimpanzee muscle strength-generating ability (M. owens polisis). (B) Biomechanical efficiency is calculated as the torque generated by the meter. The TMC of the thumb oppresses the pollicans at the joint. (C) 3D geometric morphology analysis of proportional bone occlusion at the metacarpal muscle attachment site. (© 2021 Harvati, Karakostis and Haifle / Current biology )

An article in Science journal German scientists say this was followed by hands-on analysis of “lesser, cave-dwelling” H. Naledi Who lived about 250,000 to 300,000 years ago, “and also of a sister genus,” Australopithecines. “

Using 3D technology, researchers reconstituted ancient hands and then “digitally” referred to “a vital muscle”. Harassment policis “Which is attached to the base of the palm and allows the thumb to turn inward.

The right hand of Australopithecus sediba. (Image Peter Schmid, courtesy Lee R. Berger and the University of Witwatersrand / CC BY-SA 3.0 )

How the human thumb became an electrical tool of development

After building their own dynamic 3D model of ancient hands, researchers applied increasing forces to the model. It was observed that “better, more precise grip” was achieved with greater applied force.

This, according to the authors, “will help to stabilize a needle and thread or swing a hammer.” In conclusion, scientists said that all tested members of our genus, Homo, Was “basically the same thumb grip strength,” and corresponds to the power measured in modern humans and chimpanzees’ thumbs.

During their experiment, the team observed thumb movements in two hominin samples discovered at the Swartkrans site in South Africa. About 2 million years ago, and dating from an unknown genus, the authors state that these Swartcrans fossils represent “the earliest known anthropogenic thumb in the fossil record”.

The study states that compared these two swartcrans fossils ” Australopithecines There were very weak thumbs. “And while they may exhibit device-related behavior, they have not yet developed a human level of efficiency according to the authors.

This means that it evolved about 2 million years ago as a human organ. Homo Genus, and that was the thumb that sharpened the ability of ancient humans to make more complex stone tools and weapons, enabling us to cross all other hominin groups.

This ancient human is giving us a “thumbs up” for good reasons because the latest study shows that the human thumb is what distinguishes Homo sapiens from the cousins ​​we left as we evolved into the “uber-human” . () Zemler / Adobe stock)

An excellent research project but questions remain. . .

Professor of Kent’s School of Anthropology and Conservation in Britain, Drs. Tracy kivell told C.n.n. A lot of “assumptions” are made in studies of this type because “muscles are not preserved in the fossil record.” But while acknowledging that the research involved many speculations, he said the authors of the new paper “did an excellent job of dealing with all the complexities involved in such research.”

However, there is another voice urging “caution” towards the new study’s conclusion for another reason. Dr. Avi Vereecke is an anthropologist and anatomist at KU Leuven University in Belgium, and while she openly praises the authors’ “approach”, she reported Science journal Conclusions should be treated with caution. He said, “We [evolutionary scientists] Know that ‘dexterity’ is not due to just one muscle. ”

Put another way, mastery has a huge mental component that was not accounted for by the German research team in 3D-modeling. Therefore, it is still not known how “capable” humans were applying their “super-thames” to projects that required complex foresight and predictability of results.

The full study is available with open access from Elsevier, Current Biology, DOI: https://doi.org/10.1016/j.cub.2020.12.041

Top Image: Researchers used 3D modeling software to reconstruct ancient hands and then added significant human thumb muscle to the model. Source: © 2021 Harvati, Karakostis and Haifle / Current biology

By Ashley Cowley

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