Hominins [UPSC Notes]

Digital remodelling of early ancestors or hominins (Australopithecus afarensis) shows that they were able to stand as erect as human beings. In this article, you can read more on the Hominins for the IAS exam.

What are Hominins?

Digital reconstruction was done by a Cambridge University researcher who digitally reconstructed the missing soft tissue of an early human ancestor – or hominin.

• The results of the digital reconstruction of soft tissues of Australopithecus afarensis reveal that they had powerful leg and pelvic muscles suited to tree-dwelling, but knee muscles that allowed fully erect walking. 
• The Australopithecus afarensis lived three million years ago in Eastern Africa and is an early human species.
• Australopithecus afarensis had a shorter height than present humans, and had an ape-like face and a small brain.
• The important fact to note is that they were able to walk on two legs and adapted to both tree and savannah dwelling which helped the species to survive for almost a million years.
• Dr Ashleigh Wiseman has 3D-modelled the leg and pelvis muscles of the hominin Australopithecus afarensis using scans of ‘Lucy’: the famous fossil specimen discovered in Ethiopia in the mid-1970s.
• The major muscles of Lucy’s thigh and calves were twice the size compared to modern humans as we have a higher fat-to-muscle ratio.
• Muscles made up to 50% of the total mass in humans when compared to 74% of the total mass in Lucy’s thigh.
• Reconstruction of Lucy’s muscle revealed that it had an expertise at bipedalism like humans and likely walked and moved unlike any species today.
• Lucy was a young adult, who stood at just over one metre tall and probably weighed around 28kg. Lucy’s brain would have been roughly a third of the size of modern humans.
• Dr Ashleigh Wiseman used MRI and CT scans of the muscle and bone structures of a modern woman and man to map the “muscle paths” and build a digital musculoskeletal model.

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