Scientists trying to discover last common ancestor of Humans

“How did the human lineage evolve and where did the common ancestor to modern humans evolve a shoulder like ours?”

To find out, the researchers analyzed two early human ancestors – Australopithecus afarensis and A. sediba – as well as Homo ergaster and Neanderthals, to see where they fit on the shoulder spectrum.

The results showed that australopiths were intermediate between African apes and humans.

The shoulder of Australopithecus afarensis was more like an African ape than a human, and Australopithecus sediba closer to human’s than to an ape’s.

This positioning is consistent with evidence for increasingly sophisticated tool use in Australopithecus.

“The mix of ape and human features observed in Australopithecus afarensis’ shoulder support the notion that, while bipedal, the species engaged in tree climbing and wielded stone tools. This is a primate clearly on its way to becoming human,” explained co-author Dr Zeray Alemseged from the California Academy of Sciences.