Professor Alice Roberts is back on our screens next week with Prehistoric Autopsy, which sees a team of experts reconstructing some of our ancient ancestors. We caught up with Alice to ask her about the three early human relatives that will feature in the programme.
"Our closest living relatives – chimpanzees – stand on two legs. The distinction is, are you a habitual biped? To get from A to B, is that your locomotion of choice? If it is, that causes changes in your anatomy. Lucy’s skeleton had these changes, and it’s very similar to our skeletons."
"Another piece of evidence is the ‘Laetoli footprints’ from Tanzania. One expert on Prehistoric Autopsy is Robin Crompton, who’s studied Lucy’s gait, primarily by analysing the Laetoli footprints and how they represent stepping onto the ground – compared with humans and chimpanzees. The way we form footprints reflects the pressures applied at different points, because the whole of your foot doesn’t hit the floor at the same time: pressure comes through the heel, then down onto the ball and onto the toes. And when Robin looks at Lucy’s footprint, it appears quite similar to the way we walk."
"There was a drying-out on the east side of Africa throughout the Pleistocene, so by 1.5 million years ago there was a significant expansion of grasslands. Homo erectus seems to have exploited this new environment. One suggestion is that when they walked out onto the savannah, they would’ve needed to lose heat. We’re relatively hairless compared with chimpanzees, and sweating is an effective way of cooling down because there’s no hair to trap the sweat and stop it from evaporating. It’s impossible to precisely say when we lost our fur, but this might have been the point in time."
"We did an interesting experiment on Prehistoric Autopsy: we heated somebody who’s half-naked and somebody wearing fur, then measured their temperatures to see how well they coped with heat loss. It was a fun way of looking at human physiology and what would’ve been useful to our ancestors."
"Could Neanderthals throw? There are clues in their anatomy. Archaeologist Dr Colin Shaw has looked at modern humans who regularly throw things and compared the shape of their bones to Neanderthal bones. Colin came into our studio and showed us how he reconstructed the cross-sectional shape of the Neanderthal humerus, the upper arm bone, and what that meant in terms of whether they could throw."
"We tend to think of our bones as being almost dead because we see skeletons preserved in the ground, but it’s a living tissue. If you break a bone, it will repair itself. It’s an amazing tissue – obviously it’s my favourite! Bones are plastic – they respond to their mechanical environment – so the shape tells you something about how a person used their arms during life. If you looked at the tennis player Andy Murray’s arms, his humerus would probably be larger on the racket-playing side."