Human ancestor Ardi may have 'swung from trees' like chimps till 4.4 mn years ago

It may be common knowledge that human beings share their ancestry with apes, but we are yet to see a clear picture of when humans started to walk upright, and at which stage chimps and human beings were diverted to different paths in evolution. A group of scientists have now come close to deciphering the common ancestor of humans and chimpanzees, and finding out how early humans adapted to walking on two feet.Thomas Cody Prang, assistant professor of anthropology at Texas A&M University, along with others, studied the skeleton remains of Ardipithecus ramidus or Ardi to find crucial clues to the evolutionary link. The Ardi skeleton dates back to 4.4 million years old, and was found in Ethiopia in 1992, but it took 17 years to assess their significance.Luckily, one of its hands was exceptionally well-preserved and the scientists could compare it with hundreds of other hand specimens of current humans, apes and monkeys. The aim was to test the locomotive functions and behaviours of the hominin to other fossil human relatives.[caption id="attachment_9351211" align="alignnone" width="1280"]

Ardipithecus ramidus, a hominid that lived in Africa more than 4 million years ago. Illustration: Arturo Asensio via Quo.es[/caption]Prang said as bone shape "reflects adaptation to particular habits or lifestyles" and has been considered to be an important aspect of evolutionary studies, inferences can be drawn about the behavior of extinct species like in the case Ardi. The team found evidence of a big evolutionary jump between the kind of hand represented by Ardi and all later hominin hands thus indicating that Ardi was present during a critical time of evolution.Ardi was living when adaptations to a "more human-like form of upright walking" was happening. The professor went on to connect their study with a classic idea first proposed by Charles Darwin in 1871. Darwin had suggested that the use of the hands and upper limbs for manipulating the environment had appeared in our early human ancestors to help them walk upright."The evolution of human hands and feet probably happened in a correlated fashion,” added Prang.As the study published in Science Advances has found that the early hominins evolved from an ancestor with a "varied positional repertoire including suspension and vertical climbing", our understanding of the origin of lineage gets affected.