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This program is made possible by a grant from the Women's Council of W V Z. This is an area of northern Ethiopia along the Great Rift Valley of Eastern Africa known as the Afar triangle. The triangle is formed by the emergence of three massive rift systems encompassing an area of 130000 square kilometers of generally forbidding terrain. It is populated by the fiercely independent of our people and for most of the year it is one of the hottest places on Earth. Each January there is a dramatic shift in the weather pattern. Torrential rains turned possible roads into churning tributaries eroding away layers of the

ancient landscape. This erosion pattern has turned me off our triangle into one of the most dramatic focal points in the exploration of our human past. This is the site of Hadari deep within the tribe. It is a mere 50 square kilometers a small slice yet it has produced some startling discovery. It was here in Haydar in 1974 that the famous skeleton Lucy a remarkably complete female was on earth. This fine almost single handedly revolutionized knowledge of our human origin. A year later and a mere few miles from the Lucy site another miraculous discovery took place a discovery that may have produced the First Family. The odds of finding even a single bone of an early human ancestor are small. A skeleton like Lucy almost infinitesimal.

Here at the Cleveland Museum of Natural History. The Lucy exhibit points out the locations in Eastern Africa. What are homo Lake Rudolph Olduvai Gorge Laetoli where scientists have taken the risk of searching against all reasonable odds for clues to evolution. One who has taken the risk and succeeded is Dr. Donald C. Johannsen. Curator of physical anthropology here working at the site of hot air where he discovered Lucy. Because the odds are so poor a single tooth. A small portion of a skull can be considered an important find. Joan Hanson's international team has turned up much more beating the odds dramatically. Lucy who is less than four feet tall is a 40 percent complete skeleton and

therefore remarkable. She is the oldest most complete skeleton of human ancestry from anywhere in the world. Donald Johansen who has been investigating the mysteries of human evolution in Ethiopia for the past 10 years is the American leader of the International off our research expedition the French-American group exploring the fossil rich Afar triangle. To carry out the necessarily complex logistics and objectives of the field expedition. Agreements were made with the Ethiopian government which permit removal of the fossils to the United States and France for a five year period. In Johannsen lab just weeks before the deadline. He removes the two cases containing Lucy for one final look.

He has spent months studying each of her teeth the mandible lower jaw and the overall skeleton for clues to early anatomy in a discipline that spans millions of years and attempts to chart those vast unexplored regions of time before man's brain expanded to permit language and writing. It is the quality of scientific analysis in the lab that can be as important as discovery of fossils in the field. Because he didn't want to run the last one in this way start everything with. Precision and the often difficult measurement of an ancient goal and persistent care and the almost endless interpreting and reinterpreting of new fossil finds are essential qualities for human origins research in Joel Hanssens casting lab with a deadline approaching and some fossils already being wrapped for shipment to Ethiopia. He checks the quality of recent casts and determines how many of the precious hominid human ancestor fossils remain to be duplicated.

Only one a little. Old does have the reverse in order to ensure continued study by colleagues and visiting scientists once the fossils are back in Addis Ababa record casts the first and best casts out of new molds are made by lab assistants and examined by Johannsen for imperfections. They must be almost perfect duplications of the original fossils with the cast next to the original. You're making records of as many as you can so that we know if there's something wrong with them. So if there is then then it can be remolded before we even on this quick inventory check the Jo-Ann's and shows how useful these casts are in determining the size of human ancestors. The whole bottom of it you know all this business is just like 400 of them and it's probably because of carnivore damage. Actually the

bones of these mandibles with they're scavenging that it causes is very characteristic chip and breakage when grab it loose. Teeth really perfect. It's really it's a very very big mandible because you've got to Kaino in with an enormous root and it's worn down to the level of the teeth and you can imagine how big that Cain was. This was huge huge and ended in October 1975. The French-American expedition headed by Johannsen and French scientist Maurice Taieb and Eve Copelands left the French embassy. The expedition staging area in Addis Ababa during the hard ride into the far depression. The talk among the expanded team of scientific specialists. Focused on last year's momentous discovery. Lucy what could be done to top Lucy. To many it seemed unlikely that anything could be found

more important. Than this three and a half million year old female. GEOFF CLARK Howell one of America's leading physical anthropologist and leader of the earlier Olmo expedition has had close ties with all recent expeditions to Ethiopia. The head of our expedition grew out of a geological operation in the Afar depression which began with the work of morays. You have been in the early 90s very early 1970s late 1960s and have found fossils in the head our area and in other parts of the Afar depression what he was doing geological work that ultimately led to his Ph.D. thesis and he brought in. Some French

scientists and a young student of mine Don Johannson who had worked with me in the almost several field seasons. Geologist and co-leader Maurice Taieb discovered the site of hot air as Clark Howell indicated. He spent years studying the ancient stratigraphy traveling the rough terrain in a land rover searching the vast triangle for that rare combination of ancient land coming to the surface and bringing with it the fossils of a very remote time period. Now. The off our depression in Ethiopia is a fascinating region. What is most fascinating and the reason why we're here with 15 specialists is that near the Alwash river a major tributary. Sedimentary deposits are associated with volcanic deposits and last year

in these deposits. Particularly in the deposits along the shore of the biggest ancient lake. We along with Dr. Donald Johanson of the Cleveland Museum of Natural History. Found hominid. Human ancestor remains three million years old and even older than 3 million years. The team is sure of that. It's thrilling to study these early humans. And to understand their environment. Johannsen reflects on his first visit to Haydar with Ty in 1972. And I remember driving that afternoon. That day for about six or seven hours over essentially featureless land. It was flat. There weren't any sediments exposed. It was very disappointing. And then late in the afternoon we drove up to the edge of this plateau and looked

down into the heart. It was enormously. Expansive raging. It was the moment of discovery for me at this point. There was a crystallization at that point of this is exactly the kind of place. But without a team of scientific specialists discoveries on a major scale would be impossible. You know when I started doing some research in France it was was just to go by yourself. It was time. Copeland's third poll and like Johannsen a veteran of the Olmo expedition comments on major changes he's seen in anthropological expeditions from the individual scientist with a small team to this large international effort at hata with a few hundred

specimens. Study them yourself and publish them yourself. And when you are working with the media people don't really disappear in some form and encounter. And one you are correct. You started off hundreds of humans hundreds of thousands of years. You have to have a large team which kind of can have an international. The arrival in camp by the major portion of the expedition signals the start of the third field season at hot or even if nothing new were discovered this year. It would remain one of the central locations in paleontology recommended changes and pages long and 17. Gets rid of most nights section of the menu. Larry King now. Well. After setting up camp Johannson and Copelands

complete an article on the famous and he joined discovery in 1973 the first field season at Hadar that fund of Johannsen has established the presence of human ancestor fossils at the site and encourage them to return the following year when Lucy was discovered anatomically the NIE indicated that early man walked upright. A surprising fact for such old hominid remains that concept of upright posture would become a central theme in analyzing the new Haydar fossils. All. Right. What is true. For. You. When we returned in 1975 to the Lucy side we returned to sort of look through some of the back dirt piles to collect some of the loose sediment to put them into. Burlap bags and to take them down to the river and to screen them in the river. So that we could recover all of the finest bone fragments that we possibly

could some of those that went through this quarter inch mesh screen that we had used in 1974. Feel about coming back to the site just one year. But I remember having a particular thought at the site in 1975 when I looked at the slope was sterile empty dirt. If we had not found Lucy in 1974 and if a major rainstorm as they sometimes do had come through hard or a torrential rain it could essentially have lost all of Lucy down that slope over the edge of a cliff that was nearby. And we never would have found a single Franklin or. The interdisciplinary nature of this expedition includes the geology and mapping team of Maurice Ty. Ty EB is chief geologist

Nicole PASIAS a specialist in interpreting aerial photographs. And Pierre Planck is in charge of mapping. Throughout the season. They will work closely with Johannson to make certain that all fossils discovered are placed in accurate geologic time in the field only this team can provide verifiable dating for the strata the layers of rock sand clay and volcanic deposits which hold the fossils. They are the primary source of dating information. When I take samples Marcus proximately where. I took them. Potassium argon dating can give more precise results in a laboratory but only the geologists can date the medium of discovery. Before camp closes this season. All fossils discovered will be correlated with

locations on geologic maps. One fossil that was too hastily removed from the site of discovery could not be included in the official records of the expedition. Since there was no way of determining its age simply by observation. On the morning of November 1st 1975 the first major breakthrough of the field season occurred at site 3 3 3. An adult male skull eroded to the surface was discovered by the expedition. At first all that was visible were three teeth and a block of stone. Johansen and the others recognized immediately that this was an important hominid human ancestor fossil. What he did not know was that side 3:33 would soon reveal possibly the most important set of human fossil remains in all anthropological investigation. The first family and so often one is drawn to the

romanticism of walking in the desert collecting these fossils in remote parts of the world. The attention of so many people is focused on simply the field aspect and essentially this is the first step of discovery and when one wanders across the desert terrain and sees lying on the ground such as this one which is about three and a half million years old and realizes that this is the first time that anyone's ever seen this for three and a half million years there is a tremendous amount of excitement that's generated and it is a very obviously the necessary first step but a treasure trove of side three three three did not stay hidden for long. The first family was now swiftly emerging from the deep suspended pass. See this is really interesting because.

He has been hellbound right here. Those people he was a beamer individual as big as modern man. At that spot. Three and a half million years ago those inanimate petrified pieces of teeth and bones and jaws and so forth that you're picking up are human fossils were actually life that they were walking around on the landscape very different from an amateur standing in for three and a half billion years. They were sort of in suspended animation and they weren't recognized as human beings or as human ancestors until somebody came along and found them again. It's just too much. It's so exciting. I mean you don't even have to get they are looking to see as the one that we did in National Geographic with their feet and you will see the discoveries that side 3 3 3 now known as the first family

broad elation to this remote campsite. The excavation team found over 200 specimens which according to Johannsen represent at least 13 individual men women and children who may have died together in a flash flood. Perhaps. Ice. Packs. And. Pallets and mandrels. So what we are looking at is sort of an instantaneous event. That we know represents individuals who were probably related to one another probably saw one another when we look at those fossils that we've brought back the child's cranium and the adult cranium those two individuals probably knew one another three and a half million years ago when this event happened. And there they were buried together in a common graves. What do you think. You don't find any other fossilized remains of say envelopes or rhinos because owls or whatever at the site if it were an area where bones were accumulating over

say tens of years or whatever you would find other kinds of animal bones mixed in with it but it's so unique because it really consists of only. Fossil hominid bones. Once the three three three locality had been discovered we had a major focal point for the expedition's 1975 field season. We really threw nearly all of our paleontological efforts into that one locality. We put most of our people at the site collecting and screening. All of the loose sediments that were on the slope. Because we wanted to collect as much as we could. That season. Before having to close down the camp. And wait until 1976 to returning it. One of the most exciting aspects of

3:33 is the recovery. What you see in front of you here an almost complete left hand. We have bits and fragments of also the right hand. And we have also now recovered some of the small fragments which fit into the into the ring such as small bones like this which will help us reconstruct what the wrist look like. Now this specimen is terribly important because it's one of the most probably is the most complete fossil hand that we know from anywhere. Even after the first family discovery are sharing great success for the 1975 field season. The search for new clues to man's past continues. Searching the hills of pot are is a slow sometimes tedious job requiring patience and a very sharp guy. I'll Fossel coming to the surface. We'll give you only one chance at Discovery. The next

rainfall could wash it away forever. You have to walk slowly looking carefully in all directions bending stooping searching. The Good luck of finding the fossils continued almost uninterrupted for six weeks. On the morning of December 6 the sifting team of American Mike Bush working through tons of sediment at the first family's site discovered a nearly complete child's skull including the forehead and eye orbit and ear opening and two baby teeth. Under the paleontology tent. Johansen got a first look at this 5 year old child's skull. Further evidence that early man probably lived. And in this case died together. And what was so outstanding about the 75 field seasons once the three three three discovery had been made was it virtually every day. The screening and excavation team would come back to camp

with new discoveries of teeth and jaws and the child's cranium so that every day brought with it a very special sense of excitement because as these bones came in and as we began arranging them on the tables and looking at them in detail it became more and more obvious that there were quite a number of individuals at the side. The apes of today particularly the African apes the chimpanzee and gorilla for example have a very particular way of walking and they walk like so on their knuckles called Actually knuckle walking. And when they walk like this you see there is a great tendency for this joint to collapse. And for these bones to break in an upward direction in order to prevent that sort of thing from happening in chimpanzees there's a ridge. Developed here so that when the bone. Is bending at that joint it is prevented from

moving any further in this direction. Now this is an interesting point because some scientists have suggested that man has gone through a stage where he was knuckle walking. And if this is true we should be able to see. Just at this point in the bone some evidence of this knuckle walking ancestry but with close observations of this bone We know that there is no Ridge developed on it. So we think probably now that man did not go through the stage where he was walking out of his knuckles. When you are in the field when you are actually making the discovery there is an enormous sense of euphoria with a big big manly audience. There was an enormous sense of immediate gratification. Here it

is. This is a hominid and you have this incredible sense of picking up a bone that's been buried essentially for for many years. You have this is this great reward and a great sense of excitement of of just finding the motor area. It's destructive. And it is a big thing. Then you bring it back to camp and you begin to look at it and think about it. Wonder what its anatomy was really like. But the field is always so busy you are so wrapped up in other discoveries and excavations and survey and worrying about when the cap should should close down how we're going to to leave the field if there are rainstorms whether or not the plane is going to arrive in the mail and with the spare parts you need for your Landrover and so forth that you don't really have time to sit down and do all

the detail measurements do all the details comparisons you don't have the comparative collections. It's not a time for you to really sit and do deep thinking about the fossils that you find. As the field season winds down the total collection of hominid and animal fossils is laid on the ground for wrapping and shipping. By any measure it is an impressive number. The first family. Adults and children buried together by an ancient Lakeside will be the focus of intense discussion and reevaluation of man's origins in the months and years to come. Remains of numerous animals pigs rhinos monkeys elephants and many smaller creatures have also been found. Helping to shape our understanding of the ancient environment. The now extinct ecosystem. That holds the keys to man's beginning.

Of. Reconstruction but again starting to shrink is a long way to yield. Remember this and. One of the most impressive pieces from the hot art collection that immediately stood out as being something very significant. Sending up sort of red flags saying this is something very different from what we've seen before. Where are the cranio remains. And in particular the remains of an adult skull which were found at the first family site stick turns out to be most important.

Back in Johannson lab at the Cleveland Museum of Natural History nearly four years after the discovery of the first family. Tim White from the University of California Berkeley is completing a reconstruction of an adult male skull. When finished it will be a potent diagnostic tool in analyzing adult cranial features and brain size white uses mirror imaging sculpting comparative measurement and a deep knowledge of species size and variation to determine the architecture of an early skull and a reconstruction of this sort where you have used portions of broken bone to judge what the rest of the skull will look like. It's very important that you demarcate the fossil portion that is the real portion of the reconstruction and the portion which you have essentially

made by mirror imaging or sculpting by incorporating a complete mandibular Ramus the ascending Ramus the part of the jaw that rises up above the to throw and placing that correctly we are able then to join the broken post or part of the skull with the face of the skull from 3 3 3 and join them accurately. By completing this lower jaw completing the lower dentition. We have a good idea of overall jaw shape. White now working closely with Johannsen was the physical anthropologist on

Mary Leakey's expedition to live totally in Tanzania live totally 1000 kilometers to the south of Haydar has been the source of Vasile Johannson and white believe are the same species as those from Ethiopia. One of the major things about these two sets of fossils the one from Tanzania like totally and the other from Ethiopia had are is that they fall in this time period between three and four million years ago. And in fact they're very very old hominid fossils the oldest now known. And when you have a jaw and upper and lower that fit like that from two sides that are that similar. Why it's it's evident right from the start that we're dealing with something very important and that. Further tests confirm the temporal connection between the fossils from hot air and live totally. One's called light a little. At Case Western Reserve University geologist James Aron's and uses potassium argon dating on ancient

volcanic deposits to determine the age of both sets of fossils. Model. Very vigorously. You. Worry about. It. So comparing the age of the fossils and dire we'd say that that the fossils that I die are older than 2.8. And maybe as old as 3.8 million years. And therefore they could be comparable in age to the ones that line. Between 3.6 and 3.8 million. And so where is your regular scientific data comes in further indicating that three and a half million years ago human ancestors were still apelike Johannson and Copelands complete another paper this one describing how the diet of early man affected the wear

of his teeth. I want to learn from that first. It's fantastic how strong is the way on these ideas how many of these walls never never found before. This is really typical of these pieces. It's this this ribbon as we've called it in a number of publications the ribbon like where is appears to be typical. It is now clear that in many anatomical features the brain jaws and teeth dentition that this human ancestor was quite primitive. It is primitive in the direction of being much more ape like in the sense that I think that if we saw this creature if we were able to to see a total reconstruction of what this individual looked like we would be very much impressed by the fact that from the neck up it looked very much like an ape.

But yet from the neck down it would be characterized by a walking upright walking bipedally. As human beings do today. So that in that sense what this myriad of fossils actually represents to us is a new stage in our understanding of human evolution. And in a sense I suppose using a popular term represents something more like the missing link than what we have found previously anatomist Owen Lovejoy. Kent State University before the head our finds there was essentially no fossil record of early hominids that couldn't be read with any detail. As a consequence we entered into the human history at 2000000 with a brain that was developing with a pelvis that was already bipedal and with the dentition that was well on its way toward more modern appearing anatomical configuration pushing the head fossils have

pushed these anatomical areas back in time so that we've been able to see what drops out first and what we found is that the brain as we go back in time gets more primitive as does the dentition. But the the pelvis and the locomotor system remain relatively modern looking even while Johansen and his colleagues were beginning to make interpretive breakthroughs in the lab work in the field continue to have an impact on the changing picture of human evolution. And Mary Leakey's site in Tanzania a miracle of nature was uncovered footprints left by ancient human ancestors from life totally Unfortunately our fossils are mostly composed of jaws and teeth are very broken because they were out on land surfaces for long periods of time. Hyenas were chewing them up and whatnot. So we only get the hard parts. Well what we have at life totally is a very unique circumstance that they're on the edge of the Serengeti some three to four million years ago there was a volcano and

this volcano erupting and ash was falling from the air onto the flat surface of this plane. And the consistency of this ash was very much like beach sand. And then some three and a half actually the precise age is about 3.7 five million years ago. Some of these hominids walked across this. Unconsolidated ASH after they had walked across of course there was a trail of footprints left and within the next eruption of the volcano these footprints were covered and they remain covered until 1978 when Dr. Paul Abel the geochemist with the expedition delightedly found what he thought was a hominid footprint and upon excavation of these footprints we found the trails of at least two individuals walking himself in order. Across the surface. This is a footprint that was filled with this natural cast of the bottom of one of these hominids foot. And this is actually the ash that fell into the footprint made on this surface for hominid walk through left

a footprint the volcano exploded. The ash came in three and a half million years later we come and take those apart and you can see the bottom of this hominids foot now it's a small foot but it's an extremely human foot. And this is very very strong support of the kinds of studies that Dr. Lovejoy has performed with the pelvis for instance of Lucy with the femur. The knee joint of Lucy which shows that Australopithecus afarensis at this time her it was an erect by fetal creature striding. In this case across the edge of the Serengeti Plain we would be incapable of distinguishing between the walking of Lucy and the walking of ourselves. There are anatomical differences in the limb skeleton in the houses but these are related to things like the size of the birth canal and the shape of the abdomen. But the locomotor pattern the way she walked would have been essentially identical to our own.

Dr. Lovejoy has done studies on the head ometer. He studied the knee joint for instance in the pelvis and from his studies he interpreted the locomotion to be a locomotion like our own. In other words a striding two legged form of locomotion as opposed to a chimpanzee or something like that. Now of course many people in the field question that they thought well these hominids are so old they can't possibly walk like you and I. And in fact what these footprints show is that they want it just like you and I just as Owen Lovejoy had predicted from the bony anatomy the head our collection is unusually complete and as a consequence we have been able to put together an entire pelvis from one individual. This is the cover of Lucy and it is essentially a complete and undistorted pelvis which is the first one that we've been able to look at from an early hominid. This is the anatomical part of the body which is most diagnostic as far as determining locomotion

is concerned. And this particular pelvis gives us direct evidence of bipedal locomotion in these early hominids. You can see the striking difference that exists between any dominant which is one of the parts of the pelvis from an animal like a chimpanzee. It's very long. And this blade like structure with respect to the hip socket extends for a considerable distance whereas in a modern bypass like homosapiens ourselves the ileum is extremely short and the distance between the hip socket and the blade is very short. You can see the striking resemblance that exists between the modern pelvis and this from Lucy. Again the ilium is very short. And what this means is that there's been a complete reorganization of all the muscles that operate the hip joint. And as far as Lucy is concerned all the major

changes that are required for a bipedal animal are there. And the other implication of course is is that quadrupedal locomotion is completely abandoned. Traditionally anthropologists have believed that the acquisition of upright posture and the enlargement of the brain associated with stone tool manufacture and stone tool production all went hand-in-hand. That these things were linked together that with larger brains you had considerable stone tool development and this was probably prompted by the development of bipedal posture and locomotion. We now feel that the development of bipedal posture and bipedal locomotion precedes the development of to manufacture a stone tool manufacture at least on a regular basis and substantial brain expansion by at least two million years and probably considerably more.

It means that we now have to turn around and ask ourselves new questions of what was it that prompted our ancestors who ultimately if we go back far enough we're walking on four legs. What prompted them to become upright. What was it that in either the ecological system that changed what was it in their behavioral repertoire that changed that that selected four individuals who were walking by speedily. And these are some new exciting questions that some people are exploring. Like my close colleague Owen Lovejoy as the head our collection shows the evolution of upright walking preceded the enlargement of the brain. And so we actually have to look now for a different cause for upright walking in terms of its role in the evolution of man because it is in fact perhaps the primal character. So one of the things that may be associated with it is feeding strategy.

If we look at chimpanzees today we find that chimpanzee populations often divide into two groups one composed of females and offspring and another composed of males the male group is quote responsible in the post very often for finding a food source. And if they do so they notify the other group by making loud noises by beating on the trunks of trees and by vocalizations this kind of thing. One of the possible alterations in this feeding strategy which could have been involved in early man would have been the simple change from the males of notifying the females of a food source to actually taking food back to them a process that we would call provisioning. And of course provisioning would require the use of upright walking the reconstruction of the adult male cranium from 3 3 3 is really comprised of

three major portions of lower jaw and upper jaw and face in a post here you are part of the cranium we've aligned the face and the post area or part of the skull. By using the lower jaw so the three major pieces are placed in their proper anatomical position. You know the one question regards specifically the ridges and how you're going to model the bridges because that's the only thing we don't have we have a little bit of Lucy right and a little bit for the light Toli. Now you'll see on the reconstructions that a large portion of it is made of plaster and that is particularly the portion between the face and the rear of the skull. So the real question is one of superordinate thickness that's going to determine how thick the orbit should be how thick the superior portion should be. This is just a generalized.

Mutation that could have been you know it could've been thicker. It basically is is there a lot of variation within the outer edges and margins. Tremendous. Fantastic variation just that that portion that sort of ridges over the eyeballs that are called super orbital Tor II is hypothetical and of course you have a little bit of latitude you can't put horns on it. On the other hand you can't make it a big dish in an area. You have basic primate models to follow. And the super orbital torso or the brow ridges that I've modeled here I think represent a very very likely looking reconstruction. It's is what the creature. In my estimation would have looked like. On the other hand people will question this and say Why have you made the mistake or why have you made them this thin. And my answer to that is simply when you go to a large collection of chimpanzees you find both thick and thin ones Bronston the specimen here. Is very large Momus super us that we find even in modern

humans that some individuals have very light brown ridges in fact some modern humans have none at all. On the other hand we have certain populations of modern humans that have very thick brow ridges. Even today you see these and these are much thicker. Of this is female This is male. You have that much variation within males. And. You find them in the gorillas some sort of very different type of visual aspect is changed but these are teaching Penzeys. So with that kind of variation within a single. Population of the species I'm not too concerned about exactly how we can do the reconstruction. Six years after the first major discovery of hot are five years after Lucy. Four years after the first family and one year after the footprints from life totally were on earth. Johannson and white announced that in their opinion the fossils from God are alive totally were a new species of human ancestor. They called it Australopithecus

afarensis the ape man named for the region in which the fossils were discovered. Not only were they proposing a new species an action sure to cause controversy but Australopithecus afarensis also occupied a central position in human evolution. Before the discovery of Australopithecus afarensis another species Australopithecus africanus the South African ape man was thought to be the ancestor for both the Australopithecus and homo like. Johannson and white. Now believe that their species Australopithecus afarensis may be the primary ancestor. Now with the discovery of Australopithecus afarensis a skeleton known as Lucy and her relatives from eastern Africa particularly from Ethiopia but also from Lidell we have a form which now

occupies the position that Australopithecus africanus previously occupied. It can now be placed I think without very many reservations as a common ancestor for this line which we will call Australopithecus. And this line which we'll call homo which ultimately led to modern humans in their conception of human evolution. It replaces Alfred Kanis at the base and serves as an ancestor for the whole Australopithecus line which culminated two million years ago in the highly specialized vegetarian Australopithecus robustus. This robust australopithecine was an ultimate adaptation to a vegetarian diet. This can be clearly seen I think in the enormous moders and Primos that one sees in a typical Australopithecus robustus Jonge these mowers are incredibly large. They were certainly used for the

processing of a great amount of food. And there is every indication that they had a specialized adaptation to a vegetarian diet. This is reflected also in the architecture of the skull here. As we look at this go which was found in eastern Africa one of the terminal stages of Australopithecus robustus one sees the development of a large crust on the top of the skull very much like what you see in a gorilla. And in some chimpanzees very large areas in the face for anchoring huge chewing muscles Australopithecus afarensis also serves as the source for the homo line Homo habilis then Homo erectus characterized by an increasing exploitation of a meat diet developing of a tool culture and most importantly an expanding brain and ultimately about a million and a half years ago a very successful form of human ancestor emerged out of Homo habilis with a substantial brain increase.

It was called Homo erectus. The earliest evidence for Homo erectus is this cranium known as Homo erectus from eastern Africa from the site of Lake Takano and it is a classic example of the expansion of the brain the dominance of the brain over the face the face still large but not as large when it is compared to the brain as it is in even Homo habilis or the other forms which we've spoken about. It is a new direction. It is clearly moving in the direction of modern humans. And it was a form that was enormously successful. This line led of course to homo sapiens modern man. GEOFF CLARK Howell I think the new species ism is a valid addition to our knowledge of Australopithecus. It's more primitive than Africanness. I think that's been clearly demonstrated and the material from the had are can be paralleled by the smaller but still very important collection that we know from

from totally. The most prominent criticism came from the well-known anthropologist Richard Leakey Leakey believes that the fossils from God are represent two different species rather than the single species Australopithecus afarensis which Johannson and white are proposing. Johannson has vigorously defended their interpretation using Lucy on the first family fossils to support their concept. One. Of the frequent criticisms of paleontologists whether they be human paleontologists or king paleontologists or whatever it is that they're often trying to make a case about a new species or on the basis of a couple of teeth or a bit of a jaw or a fragment of a skull or something. In this case we've literally got hundreds of specimens. I mean this is just a very few specimens from the entire collection that

we see here on the table in front of us. And this collection that represents the new species Australopithecus afarensis is quite large indeed one of the largest collections of fossil hominids fossil of human ancestors known to anthropologists from anywhere in the world. And in having a collection as large as this it has permitted us to see a very or to understand a very important aspect of all biological organisms and that is particularly the range of variation. In other words if you find something that is big and something that is small the first question is are they different species is one a small species and one of the large species and this is indeed a question that we asked early on is Lucy because she's so small a distinct species from the things that are large at the site. But as we began to find more and more specimens and particularly the material from the first family site we began to realize that there was a gradient that you could go from very small individuals to very large individuals with all of the steps in between that it wasn't a distinctive

separation between large and small individuals. And that seems rather astonishing when you look at some of the specimens we have for example whereas here this this mendable from the first family site is a large deep mandible from the same site we have mandibles much smaller in size such as this but also at the site we have mandibles that sort of span the gap in terms of size between large and small individuals. And we feel that this sort of range of variation is not excessive for a single species and a possible plausible interpretation is on the one hand you have large males and smaller females. You do have at this one site individuals such as the small one here that are essentially the same size as Lucy and holding Lucy's lower jaw here and on is holding a small one from the first family site. And we are interpreting these individuals as female. Very good interpretation for Lucy because when we have her pelvis frontside we know that she's a female

for the specimen. It's on the smaller end of the range of variation and so we interpret that one also as a female and this level of difference between the sexes is normal among higher prices in particular among the apes and humans. Yeah I mean I don't understand why some people were so astonished to see such a range of variation. I mean just as a random sample of gorillas that we have in front of us from our collection you can take individuals like that which are enormous. That's a male gorilla. But yet here is another mandible of a of a gorilla which is a female and you can see how much difference in size there is between these two mandibles or lower jaws of a gorilla. Yet these fit comfortably within a single species. I think there's no question that the procedure that's been followed and the adoption of the a new species is absolutely valid and I believe anyone who who has the experience and also has the time to study the vast amount of material that's come out of the had are and there's certainly a lot more there if one could work there again.

We'll agree that the species is a valid one and it seems that we we are so often burdened with the trouble of just simply names because somebody when they talk to us now frequently about. Australopithecus afarensis they seemed to be attacking us on the basis of simply the name. But when you sit down with them you talk to them you explain the whole process of evolution how this fits in to a better understanding of early hominid phylogeny or evolution then the name sort of falls away. It's not important anymore. And the Homo habilis controversy in the early 60s when Lewis Leakey and his colleagues named Homo habilis there was such a concentration and very simply the name that the importance of Homo habilis for understanding human evolution was essentially swept under the rug. And that's something that we have really battled against and we'll have to continue to battle against I think is this this sort of impression that a new name makes on people because that's not what we're really

interested in. I mean we could call this anything. We're in a state in anthropology now where it's really become a science and that means that points of view and theoretical stances and so on are are going to be subject to extreme scrutiny by people. It's fantastic. You think there's more up here you in. The. Search for human fossils the actual remains of our ancestors is a difficult sometimes torture was endeavor. Louis Leakey worked for nearly 30 years at Old gorge hoping to find hominid fossils. But discoveries were finally made on the commitment vindicated. Others have gone into the field armed with good scientific good intentions and come up empty handed. Donald

Johanson on the International off our research expedition. I've been a dramatic exception. Making spectacular finds. Lucy on the first family and successive field seasons. Some of it was luck some the result of this new multi-disciplinary approach which brings many scientists together to investigate the human past. The result is that these discoveries have changed our understanding of human evolution how we evolved into ourselves. Will the new species Australopithecus afarensis remain the primary ancestor. It may although as Johannsen has said new discoveries could change his conception of human evolution. What is certain is that this team has beaten the odds dramatically and uncovered essential links to man's distant past. The big question is how that really counts on the face.

And you're really limited where does it come from. And that you've got you've got restrictions on the length of the mandible the descending remissness room ruined for instance any one of these chimpanzees you are face is defined in terms of its articulation with the post poster on this of matter since we have any untagged or amount of lower drop that defines this joint. This joint is really the relationship between that and and that's what we've done is for you to reconsider. That's just a few things happening very very low very even anteriorly measured from the earth is much more like. And you don't want to slope this part of the face back if you like. You've got no proof all along. That's right. No it has a shorter face than modern names got to much longer face than on top of their home and this program has been made possible by a grant from the Women's Council of WB

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