Digging for humanity’s origins – Louise Leakey


who are we that is the big question and essentially we are just an upright walking big brain super intelligent ape this could be us we belong to the family called the humanity we are the species called Homo sapiens sapiens and it’s important to remember that and in terms of our place in the world today and our future and planet Earth we are one species of about five and a half thousand mammalian species that exist on planet Earth today and that’s just a tiny fraction of all species that have ever lived on the planet in past times we’re one species out of approximately one let’s say at least sixteen upright-walking apes that have existed over the past six to eight million years but as far as we know we’re the only upright-walking ape that exists on planet Earth today except for the bonobos and it’s important to remember that because the bonobos are so human and they share 99% of their genes with us and we share our origins with a handful of the living great apes it’s important to remember that we evolved now I know that’s a dirty word for some people but we evolved from common ancestors with the gorillas the chimpanzee and also the bonobos we have a common past and we have a common future and it is important to remember that all of these great apes have come on as long and as an interesting evolutionary journey as we ourselves have today and it’s this journey that is of such interest to humanity and it’s this journey that has been the focus of the past three generations of my family as we’ve been in East Africa looking for the fossil remains of our ancestors to try and piece together our evolutionary past and this is how we look for them a group of dedicated young men and women walk very slowly off across vast areas of Africa looking for small fragments of bone fossil bone that may be on the surface and that’s an example of what we may do as we walk across the landscape in northern Kenya looking for fossils I thought many of you in the audience can see the fossil that’s in this picture but if you look very carefully there is a jaw no a jaw of a 4.1 million year old upright walking ape as it was found at Lake Turkana on the west side it’s extremely time consuming labor-intensive and it is something that it’s going to involve a lot more people to begin to piece together our paths we still really haven’t got a very complete picture of it when we find a fossil we market today we’ve got great technology we have GPS we mark it with a GPS fix and we also take a digital photograph of the specimen so we could essentially put it back on the surface exactly where we found it and we can bring all this information into big GIS packages today when we then find something very important like the bones of a human ancestor we begin to excavate it extremely carefully and slowly using dental picks and fine paintbrushes and all the sediment is then put through these screens and where we go again through it very carefully looking for small bone fragments and it’s been washed and these things are so exciting they are so often the only or the very first time that anybody has ever seen the remains and here is a very special moment when my mother and myself were digging up and some remains of human human ancestors and it isn’t one of the most special things to ever do with your mother cannot many people look and say that but now let me take you back to Africa two million years ago I just like to point out if you look at the map of Africa it does actually look like a hominid skull in its shape now we’re going to go to the East African and the Rift Valley essentially runs up from the Gulf of Aden or runs down to Lake Malawi and the Rift Valley is a depression it’s a basin and rivers flowed down from the highlands into the basin carrying sediment preserving the bones of animals that live there if you want to become a fossil you actually need to die somewhere where your bones will be rapidly buried you then hope that the earth moves in such a way as to bring the bones back up to the surface and then you hope that one of us lot will walk around and find small pieces of you okay so it is absolutely surprising that we know as much as we do know today about our ancestors because it’s incredibly difficult eh for these things to become to be preserved and secondly for them to have been brought back up to the surface and we really have only spent fifty years looking for these remains and begin to actually piece together our evolutionary story so that’s good too Lake Turkana which is one such Lake basin in the very north of our country Kenya and if you look north here there’s a big river that flows into the lake that’s been carrying sediment and preserving the remains of the animals that live there fossil sites run up and down both lengths of that lake basin which represents some twenty thousand square miles that’s a huge job that we’ve got on our hands two million years ago at Lake Turkana Homo erectus one of our human ancestors actually lived in this region you can see some of the major fossil sites that we’ve been working in the north but essentially two million years ago Homo erectus up in the far right corner lived alongside three other species of human ancestor and here is a skull of a homo erectus which have just pulled off the shelf there but it is not to say that being a single species on planet Earth is the norm in fact if you go back in time it is the norm that there are multiple species of hominids of human ancestors that coexist at any one time where did these things come from that’s what we’re still trying to find answers to and it is important to realize that there is diversity in all different species and our ancestors are no exception there’s some reconstructions of some of the fossils that have been found from Lake Turkana but I was very lucky to have been brought up in Kenya essentially accompanying my parents to Lake Turkana in search of human remains and we were able to dig up when we got old enough fossils such as this a slender snouted crocodile and we dug up giant tortoises and elephants and things like that but when I was 12 as I was in this picture a very exciting expedition was in place on the west side when they found essentially the skeleton of this Homo erectus I could relate to this Homo erectus skeleton very well because I was the same age that he was when he died and I imagined him to be tall dark skinned his brother certainly were able to run long distances chasing prey probably sweating heavily as they did so he was very able to use stones effectively as tools and this individual himself this one that I’m holding up here actually had a bad back he probably had an injury as a child he the scoliosis and therefore must have been looked after quite carefully by other female and probably much smaller members of his family group to have got to where he did in life age 12 unfortunately for him he fell into a swamp and was and couldn’t get out essentially his bones were rapidly buried and beautifully preserved and he remained there until 1.6 million years later when this very famous fossil hunter Camille Camille walked along a small hillside and found that small piece of his skull lying on the surface amongst the pebbles recognized it as as being hominid it it’s actually this little piece up here on the top well an excavation was begun immediately and more and more little bits of skull started to be extracted from the sediment and what was so fun about it was the skull pieces got closer and closer to the roots of the tree and fairly recently the tree had grown up but it had found that the skull had captured nice water in the hillside and so it had decided to grow its roots in and around this holding it in place and preventing it from washing away down the slope we began to find limb bones we found finger bones the bones of the pelvis vertebrae ribs collarbones things that had never ever been seen before and in Homo erectus it was truly exciting he had a body very similar to our own and he was on the threshold of becoming human well it’s shortly afterwards members of his species started to move northwards out of Africa and you start to see fossils of Homo erectus in Georgia and China and also in parts of Indonesia so Homo erectus was the first human ancestor to leave Africa and begin its spread across the globe some exciting finds again as I mentioned from Dmanisi in the Republic of Georgia but also surprising finds from recently announced from the island of Flores in Indonesia where a group of these human ancestors have been isolated and have become dwarfed and they’re only about a metre in height but they lived only 18,000 years ago and that is truly extraordinary to think about just to put this in terms of generations because people do find it hard to think of time Homo erectus left Africa 90,000 generations ago we evolved essentially from an African stock again at about 200,000 years as a fully fledged us and we only left Africa about 70,000 years ago and until 30,000 years ago at least three upright-walking its shared the planet earth the question now is for who who are we were certainly a polluting wasteful aggressive species with a few nice things thrown in perhaps for the most part but you’re not particularly pleasant at all we have a much larger brain than our ape ancestors is this a good evolutionary adaptation or is it going to lead us to being the shortest lived hominid species on planet earth and what is it that really makes us us I think it’s our collective intelligence it’s our ability to write things down our language and our consciousness from very primitive beginnings with a very crude toolkit of stones we now have a very advanced toolkit and our tool use has really reached unprecedented levels we’ve got buggies to Mars we’ve mapped the human genome and recently even created synthetic life thanks to craig Venter and we’ve also managed to communicate with people all over the world from extraordinary places even from within an excavation in northern Kenya we can talk to people about what we’re doing as albor so clearly has reminded us we have reached extraordinary numbers of people on this planet human ancestors really only survive on planet Earth if you look at the the fossil record for about on average a million years at a time we’ve only been around for the past 200 thousand years as a species yet we’ve reached a population of more than six and a half billion people and last year our population grew by 80 million I mean these are extraordinary numbers you can see here again taken from Al Gore’s book but what’s happened is our technology has removed the checks and balances on our population growth we have to control our numbers and I think this is as important as anything else that’s being done in the world today but we have to control our numbers because we can’t really hold it together as a species my father so appropriately put it that we are certainly the only animal that makes conscious choices that are bad for our survival as a species can we hold it together it’s important to remember that we all evolved in Africa we all have an African origin we have a common past and we share a common future evolutionary speaking we’re just a blip we’re sitting on the edge of a precipice we have the tools and the technology at our hands to communicate what needs to be done to hold it together today we could tell every single human being out there if we really wanted to but will we do that or will we just let nature take its course well to end on a very positive note I think evolutionary speaking this is probably a fairly good thing in the end I’ll leave it at that thank you very much you

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