Jimmy Doherty: So this would have been a fossil Darwin would have examined?
Chris Stringer: Yes, well he certainly never, I don’t think he examined the original but there were replicas of it which he would have seen, and which certainly Huxley had studied.
Jimmy Doherty: Incredible. And what’s next?
Chris Stringer: Okay, well now we’ve got evidence that turned up after Darwin had died, and of course Darwin had said that he, at least he thought it was most probable that our line of evolution began in Africa. But in his time there were no human fossils, but from about 1924 fossils started to turn up in Africa. And here’s one from South Africa that we think is about 2¾ million years old, and this is the stage of evolution, I mean Darwin would have been delighted to have known that something like this existed because this is a creature known as an Australopithecine, a Southern Ape, and it’s a creature which walked upright but still had a very ape-like skull and brain size.
Jimmy Doherty: And what’s the time difference between this and Neanderthal?
Chris Stringer: Well, enormous. So this Neanderthal 40,000 or 50,000 years old, this fossil 2¾ million years old.
Jimmy Doherty: Good Lord.
Chris Stringer: So our evolution in Africa goes back a very long way.
Jimmy Doherty: That is incredible isn’t it. And I just think it’s one of our ancestors.
Chris Stringer: Yeah, and you can see straight away the difference in brain size.
A Neanderthal has essentially a modern human brain size, this has a brain about the same size as a chimpanzee’s.
Jimmy Doherty: Good Lord.
Chris Stringer: And what’s interesting is, of course, that associated with those Australopithecines, Southern Apes, are parts of the skeleton such as this part of a pelvis, so this is a hip bone belonging to the find known as Lucy, nicknamed Lucy. And this find is over 3 million years old and it’s her hip bone, and what’s interesting is there’s the socket for the thigh bone and this is a human shaped pelvis, so her pelvis was like ours, it was short and broad which shows that she was walking upright.
Jimmy Doherty: She was walking upright as well.
Chris Stringer: Yeah, yeah.
Jimmy Doherty: All that time ago.
Chris Stringer: So over 3 million years ago creatures were walking upright. And Darwin was right about that because he thought that walking upright would have come before the enlargement of the brain.
Jimmy Doherty: Darwin was a genius at predicting things.
Chris Stringer: Yeah.
Jimmy Doherty: You know, and looking at the evidence around him and sort of guessing in some ways, or thinking well I can see how it would have been, and it’s absolutely phenomenal.
Chris Stringer: Yeah. And he argued also of course that once our ancestors were walking upright they would have their hands free, then they could start to manipulate their environment, they could start to make tools. And we have here, it doesn’t, not much to look at but this is a pebble tool made out of lava from Africa that’s over 2 million years old, and so this is the oldest technology we know about, the oldest form of stone tools were these very simple chopping tools.
Jimmy Doherty: So that was done for bashing, and then you’ve got some chopping here as well.
Chris Stringer: That’s right. And of course you may think well, you know, there must be loads of these lying around, how do you know it’s a tool. Well these are found alongside the skeletons of animals that have had their bones smashed and the bones are covered in cut marks, so these have been used to cut off flesh from carcases, to smash open bones to get the marrow out, and that’s what our ancestors were doing in Africa 2½ million years ago.
Jimmy Doherty: Incredible. And what’s last you’ve got in there, something fantastic in there?
Chris Stringer: Here we’ve got a fossil which does provide a nice bridge between the Australopithecines, the Southern Apes, and something like us and the Neanderthals. So we’ve got here a creature called homo erectus, and this skull is about 1¾ million years old, so the brain size now is about double the size of the Australopithecine brain, but it’s still only about say a half or two thirds at most of our brain size today.
Jimmy Doherty: That is incredible.
Chris Stringer: So here’s a sort of, so we’ve got here at least an approximation of an evolutionary sequence of increase to the brain, decreasing size of the face and the jaws, and of course the skeleton changing too towards a totally modern skeleton.