 Karen has taught me, and so Karen will be introducing Dr. White here. Good morning. Tim White has a distinguished research career in paleoanthropology as both a discoverer and an analyst of the fossil record of human evolution. He is professor of integrative biology and co-director of the Laboratory for Human Evolutionary Studies at the University of California at Berkeley. He received his PhD in biological anthropology from the University of Michigan at Ann Arbor. The man ranges. If you check his museum connections, they range from Yunnan province in China to Croatia to Kenya to Cleveland. His fossil finds range from Artipithecus ramitus of 4.4 million years ago to Homo sapiens adultu of a mere 160,000 years ago, with Australopithecus atherensis, including Lucy, Australopithecus garhi, and an Ashulean toolkit toting Homo erectus in between. The subject matter of his publications ranges from post-canine plioplasticine dentition to sexual dimorphism in robust Australopithecines, with a recent contribution on the history and prehistory of cannibalism. By the way, if you think science is dull, but you like CSI, just think of Tim White as the guy who works the really cold case files. You may also want to be on your guard for gory metaphors. He might tell you that some people find the evidence for cannibalism, quote, impossible to swallow. A few years ago at this Nobel conference, I was seated next to a molecular biologist who assured me that this year's conference panel would have only molecular biologists. Paleontology was apparently too antiquated. Eyebrow raised, I claimed the dubious pleasure of responding. Oh, really? Is that why the conference organizer has asked me to invite a human paleontologist? That was more or less the end of that conversation. But I think that it is helpful to remember that science happens both in the field and in the laboratory, and that the puzzles to be solved are too daunting to yield to any single methodological bias. Part of the fascination and foundation of science remains in the mystery of ancient footprints and in a sky full of diamonds. So I present Tim White, scientific analyst and field worker, who is also known for cultivating fieldwork itself as an exercise in human relations. His presentation today is entitled, Evolution, A View from afar. I want to first thank Karen for that wonderful introduction, and thank also Tim Robinson, President Peterson, the sponsors, and the college. And ladies and gentlemen, thank you all for coming. It's an honor to be included among such distinguished colleagues, and it's a distinct privilege to be on a campus that has such a sense of warmth, of welcome, of community, of scholarship, of free inquiry, indeed of excellence. I'm very, very happy to be here today. Today I'll present a progress report on the operations of a large and ongoing research project in the Horn of Africa. I'm a spokesman for approximately 50 scientists who work together on this project, and I'd like to share some of the things that we've learned about human evolution, and I'd like to share a little bit about how we've learned them. This study area in Ethiopia is known as the Middle Awash. It's in the Awash Valley. It contains a deep deposit of sedimentary rocks. This deposit of rocks measures over a kilometer in thickness. That's 10 times thicker than the sediments that Louis Leakey made famous at Olduvai Gorge in Tanzania in the 1960s. The sediments on the top of that Middle Awash sediment stack are still being deposited today. The ones on the bottom of the stack lie beneath an ancient lava flow, a lava that cooled 6 million years ago. The stack itself has now been disorganized by tectonic activity during the 6 million year interval of its deposition. We've had to piece it back together again. Now because the Middle Awash sediments contain bones and artifacts, they give us a fine opportunity to test different models of human origins. And this morning we'll explore how this fossil record has been formed and altered by the contingencies of death, burial, fossilization, exposure, and discovery. At the end of the talk we'll look at how some new evidence is reshaping our ideas about the most famous of fossil people, the Neanderthals. And I thought that this would be particularly appropriate the day after the California recall collection, or should I say, California. Most species that have lived on this planet are now extinct, including our closest relatives, the Neanderthals. We know that the chimpanzees of Africa are our closest living relatives because they share so much of their genome with us. But compared to them and to all of the hundreds of other primates, indeed the thousands of other mammals, we humans are very, very odd. We're very unusual. We're in fact bizarre. And one of the questions that we're pursuing in human evolutionary studies is really quite simple. How did this happen? How did we get this way? Well, there are many different explanations, and we heard many of them yesterday. I'd like to offer you one other one, a distinctly American explanation. This is by the great American author, Mark Twain, who wrote in 1897, Man is the religious animal. He is the only religious animal. He is the only animal that has true religion, and he has several of them. Indeed, anthropology teaches us that every culture has a myth about how people were created. There are Babylonian, Hindu, Cherokee, Yoruba, Maori, Norse, Mayan, indeed dozens of other myths. Are any of them accurate? A November 1997 poll by the Gallup Organization quizzed Americans about their views on the origin of humans. 44% of the American public agreed with the statement, quote, God created human beings pretty much in their present form at one time within the last 10,000 years or so. Now as you know, many of the models favored by modern-day creationists have their roots in the pastoral societies of the Middle East. And whatever literally interpreted biblical creation model we choose, its prediction is clear. We should see anatomically modern people all the way back to an abrupt origin in the oldest sediments that we can find. In other words, according to this model, it's been all modern humans all the time. So let's look at some evidence if we can go to the slides. This is a slide that is actually a religious advertisement. It's an advertisement for a book. You used to be able to purchase this book to demand get here by evolution or creation for only 60 cents. The price has probably gone up. I put this up because how many times do you get to see religious advertising that actually uses attractive naked people? The Middle Owash Research Project is a very large project. I'm showing here its youngest member. This is an African wildcat named Lubaca and one of the excavators on the team. Now, paleoanthropology is an endeavor, as Karen mentioned, that involves not only the field work but the laboratory analysis. And this is often forgotten when we see at the end of the day the publication in scientific journals, which these days is immediately picked up and broadcast to a global audience. But we're engaged in the search for fossils, and only sometimes do we get this far, which is the actual discovery of all. A lot of times we don't find very much at all. When we do find something, we have to extract it. It comes into the museum and laboratory where it's prepared, analyzed, and written up. And I'll be talking about fossils today that are at various stages along this pipeline, if you think of it in that way, of paleoanthropology. The project that I represent has been working since 1981. We are supported by the National Science Foundation and the IGPP of Los Alamos. A number of different countries are represented on the project. Specialists involve scientists who span a lot of the biological and social sciences, ranging from archaeologists to paleobotanists, geologists, all working together with the sort of singular objective, and that is learning about the past. And the past that we're interested in is actually, in geological terms, a fairly recent past. We're going to be dealing with that kilometer of rocks today. And this diagram shows you that kilometer of rocks stacked up from youngest down to oldest. The detailed names are not important here. These numbers are, that's five million years, and you see here that we have some sites that go all the way back to 5.8 million years. We'll be first looking at those, and there are a couple thousand vertebrate fossils known. These are the publications that have come out on these fossils over the years, and some of these are still in the pipeline, including approximately 6,000 vertebrate fossils from a very unique locality called Aramis that's dated very accurately to 4.4 million years ago. We'll then move up to the 2.5 million year mark and see what's happening there on our trip through time. We'll move up to the million year mark and then on up into some of these more recent Pleistocene sediments that were published last year. That's where we're going in terms of time, but we have to also understand where we're going in terms of space. And the best way to do that is to start with this map, which shows the Horn of Africa. And the geography of this region today is conditioned by the forces of tectonics that have been operating there for a long time. Some 30 to 40 million years ago, vast outpourings of lava formed a very large dome, and that dome was later to split. And what's been happening is the Arabian plate has been moving in a counterclockwise direction away from Africa, and this has resulted in the creation of the Red Sea Rift. It's now full of seawater. The Gulf of Aden Rift formed as that Arabian plate pulled away from the Somali plate, and indeed the Somali plate itself is pulling away from Africa, forming what's known as the Great East African Rift coming down here. Our study area is here in this triangular depression known as the Afar, or the Afar Depression. It's in a country that is a wonderful, beautiful, extraordinary country called Ethiopia, whose capital is here in the highlands about 7,000 feet up on the shoulder of the modern rift valley. It's Addis Ababa. And what I propose to do here is to put you all on a space shuttle. It used to be easier, but here you are looking down at the planet from the shuttle, and you're seeing here the Arabian plate pulling away. There's the Red Sea we just looked at, over here the Gulf of Aden, and underneath we have this triangular depression that is rimmed by clouds. And that cloud deck is very important because to understand all of the process here and understand why this is such a key and important area in human evolutionary studies, you have to think about the water. The water that comes when these clouds produce rain comes down onto that dome of Ethiopia, and the water is shed in this direction to the north, and it ends up going past the pyramids of Giza and into the Mediterranean. But if the water falls just on the other side of the drainage divide, then it goes into the Afar Depression, and that's the key to the whole thing. Most of the rest of Africa is not depositional, but sediment deposition has been occurring here. So in the next photographs, and there are two of them, we're going to go down on the ground. One of them is going to look into this drainage, and the other one will look down into the Afar drainage. So here we are. This water will actually end up in the Mediterranean, but I want to call your attention to what's happening to the water here on the rift margin when it does rain. This is obviously not raining today. Here we have a horse that's out grazing along the side of the rift. And the question I want to ask here is, how might we insert this horse into a fossil record for future paleontologists? And really the answer is pretty simple. The first step is to kill the horse. The second step is to not kill the horse here. Because if we kill the horse here, we're going to have to haul it somewhere else. So we just dug a hole and buried it right here. Even if the hole was 10 meters deep and we buried the horse, in about three or 4,000 years, the erosion that goes on every year with the rains in these highlands is going to excavate those bones. The bones will come out before they're fossilized. They'll tumble down this slope, and by the time they reach the Afar floor, they will be dust. Dust is not a very good form of fossil bone for a paleontologist to use. So we really have to go somewhere else. And the somewhere else is way out into that depression. This is a view roughly to the south. You can't see the Somali escarpment on the other side. It's covered with haze, but we're going to go way down, and we're going to follow the water. And the water ends up forming the Awash River, which drains into this Afar depression. We see here the water itself, and this is in the dry season. In the rainy season in Ethiopia, which is during the summer, the Awash River comes up because of all of the rains draining from the highlands, and those rising waters will cover this lower jaw of the horse. And in fact, it's interesting the way paleontology work. We tend to get the hard parts, the parts that are left, thus destroyed by natural forces. We get a lot of teeth and jaws. So when this water comes up with its thick, muddy sediment load, it will cover this bone and it will embed the bone. That's the first step in preservation. Now, if everything is just right, the preservation conditions are right, the bone will actually turn to stone. It will fossilize, and it will be entombed in these sediments, and more and more sediment will be deposited on top of this. And as I said, these are just the top sediments. If you went straight down, you'd go through a kilometer of sediment to get to the oldest ones at six million years ago. Obviously, we can't do that here. It's quite wet to dig in this area, and we don't dig very much. We let those tectonic forces do the work for us. They do another thing for us that's very important, and that is they weaken the earth's crust. And what that means is that magma can exploit the weakness and it can come to the surface in the form of... Oh, we didn't want to do that. In the form of this volcano. This is about... I can't quite point at that one, I guess, but this volcano, use your imagination, rises about 1,600 meters above the off-ar floor. It is an explosive, solisic volcano. It is not currently active, but it could reactivate at any time. You can see it's a quite youthful volcano. And when these volcanoes erupt in the off-ar, and indeed along that entire fracture zone of the rift, they eject very large volumes of material that'll come back to be important for us in a little bit. If we then run the clock forward on our horse jaw, it'll look something like this four million years from now. Actually, this is a hippopotamus jaw that was deposited in a similar environment about four million years ago. And the erosional surface has now just reached the jaw. The jaw has turned into something like porcelain, very brittle, very fragile. When it emerges on the surface, it shatters, so all of its pieces of teeth and jaw are scattering across this surface. And here we have the fossil collector looking around on the surface. And in any given day, walking these outcrops in the off-ar, you see literally thousands of these fossils. Usually not as nice as the hippopotamus. Usually they're much more fragmentary. So here's the survey team of geologists, archaeologists, and paleontologists. Walking around on the off-ar landscape, there's our volcano in the background, gosh, river we've met. These sediments are two and a half million years old. So we're about halfway down the stack right at this position in the study area. We know that from this white patch, which turns out to be a volcanic ash horizon. It's been dated by argon-argon dating to two and a half million years old. We're going to come back to these deposits and look at their contents in a little while, but I promise to take you to the bottom of the pile first. Before we do that, I want to introduce you to the people who live there. This is an off-ar man standing guard with a rifle over this paleontology crew so it can go about its business without having to look over its shoulder because some very large lions live right along the riverine forest right there. And it would be a very bad thing if some of these paleontologists were to become prematurely fossilized. So let's go to the off-ar man's village and meet some of the local people. These are Islamic people. These are the pastoralists. They have lived for centuries in this very, very harsh environment, really in the rain shadow created by the formation of the rift itself. It's a zone that does not have enough rainfall to produce agriculture, and so they rely on their animals. These animals live in corrals with the people every night. This is during the day. The animals are out taking water back here in grays. This happens to be a village during the dry season so people have congregated close to the water and grays sources. At night these animals, the goats and camels, cows will be brought back into these enclosures. The architecture there, a series of houses that are built and covered with this is sort of a almost a Neolithic Winnebago in a sense. You have grass mats that are woven. Well, it's just easier to show you. These are the curved sticks that form the framework for these houses, and then they put the grass mats over the house, and that is an off our house in one of these villages you can see behind the house. And of course when it's time to go, when there's no more grass for the animals in this particular area, the people move on, and so everything is put onto the camels and moved to a different location. This is back on the Bury Peninsula. We're going to go into the lecture and see what those people are doing there. These are the paleontologists. These are the moving off our... We're going to first go out to a central place in the study area so I can orient you to the study area spatially. And we're going to keep working back and forth between time and space in this study area. So we start in the center. We're looking off here to the east. We see a large and prominent and we see some sediments out here. We see the ladies house right there. And we're going to be visiting a site over here. We're going to be visiting another site there. But the first thing we better do is orient ourselves because this is very low lying topography. It's not like the Grand Canyon. It's really not scenic at all. So we've got to get up above it to get a sense of perspective. To do that we'll use this map and here's your kilometer scale up here. Think of it that this lake, which is about 10 kilometers long. We've been looking at that the women's house is right out there. So we were standing there and we were looking off in that direction toward that volcanic high and we'll go back there. But the oldest rocks are in the other direction. They're over here along the western margin. And about 10 years ago a graduate student of mine, Johannes Haile Selassie started to work the rocks in this area with a colleague named Emily Gabriel who works at Los Alamos. This is extremely difficult terrain. We're going to look in the next slide against the western margin and we will see the effects of that rifting. And here it is. You're looking dead into the margin and you can see the stair step topography. Well in the wall of the front scarf you'll see sort of whitish patches and these whitish patches are sediments. And they are being eroded today and we know from the volcanic horizons that cap them and underlie them that they're about 5.8 million years old. And they have produced some of the earliest human ancestor fossils in the world. This time period we've only begun to put fossils into in the last five or six years. It's a story that is in progress. But it already has come to quite a bit of prominence. I want to put this slide up and say a couple of things about it. We are back at a time that the molecular biologists predict that we shared a common ancestor with the living apes, the modern chimpanzees. We did not evolve from modern apes. Modern apes live in the forest and in the zoo and we shared at some time in the past a common ancestor. We haven't yet found that common ancestor. We'd like to know what it's like but we shouldn't assume that it's a chimpanzee. Because chimpanzees have been evolving for the last 6 million years just as human beings have. We have a much better fossil record in fact for human beings and I'll be talking about that record today. To find some of that evidence we can go to the next level up. We're out now in the center. We've looked at this volcanic high in the photograph taken from the woman's house. It's not from the surface. In this case it's a fossil pig. This capping mesa right up here is formed from a lava flow that's a little bit resistant to erosion. The sediment underneath it was wet when that lava flow poured out and baked the sediment. By measuring the argon gas trapped in that volcanic rock we've estimated it's aged to 5.2 million years old. So all of the fossils that we find below it are from below that horizon. We now are going to take a step up in the stratigraphy. Go a little bit younger in time and all the sediment on top of the basalt has now washed away. So we're going to have to go way up in the air. In fact the best way to do it is in a light aircraft. So imagine we all got in a light aircraft. It wouldn't be light anymore if we all got in it. And we use this for a landing strip and we took off and we're now at the bottom of the section. The lava flow that we saw before is now down on the bottom of a stack of sediments and from about the arrow there to the top of the stack out there there are about 300 meters. That's about three football fields stacked on end. And very important horizon right here through the middle of that outcrop. See the whitish rock right there. That's a volcanic ash that was erupted 4.4 million years ago. All through these erosion gullies in a drainage known as Aramis. We published the first results in 94 and we're working on some other fossils that we found. In fact there are about 6,000 vertebrate fossils sandwiched in a 2 meter stratigraphic interval mostly flood plain that was covered there at 4.4. We have invertebrate fossils, snails. We have fossilized wood. Here's a fossil millipede. This is an interesting structure in the center. This is a fossilized ball that was rolled up by a dung beetle 4.4 million years ago. And all the little objects out here are seeds from a tree named Celtus africana. So a very different environment 4.4 million years ago. Indeed a world very different from our world. There was a very large bear who lived in Africa 4.4 million years ago. And there were other creatures as well. Oh, there's that digging cat. I told you that the cat was an excavator. This is an excavation that went on for 3 years. Plenty of time even to train cats how to excavate. In the first year we found eroding to the surface a very fragmentary, highly crushed very soft partial skeleton. And partial skeletons are the Rosetta stones of the world. They give you the functional links. They tell you how the bodies moved what the organisms ate what the relationship of brain size to body size was. So my colleagues, Dr. Dr. Johannes here taking a break from his West margin work is holding the lower jaw of this partial skeleton which we're still working. We have six physical anthropologists working on this and hope to publish in the near future. And a lot of other work as well. And in this field, as you know the hominid fossils command an extraordinary amount of attention and that's unfortunate because it's not just the hominids that these people are interested in understanding. It is understanding the context the world in which these hominids live and so when you have specimens like this what is this anyway? This is a pin that's the head of a pin that's a little bit of sticky wax and this is the lower jaw of a bat that flew in the night skies of Ethiopia 4.4 million years ago. It is one of dozens of new species of micro mammals found in the same layer as the hominid and the bear and the pigs. In fact we've recovered in a sense a snapshot of the past at 4.4 million years ago. So we can learn a great deal about our evolution but we're actually interested in that more holistic manner with this large team of specialists. Well how does this team operate, logistically speaking? Well we start in the capital of Arasababa at the National Museum. We load up the supplies because we know when we end up at the field camp on the off our floor most of the meals will be canned or goat. So this action packer is actually full of Kool-Aid it's a very important part of the project. The water often doesn't taste so good out there. We're here building the road down coming down to the off our floor. There are no roads, no bridges in this area. It's extremely remote. Finally when we're on the off our floor oh there's that horse. Remember the horse that turned to dust? Doesn't do us any good as paleontologists. To do this kind of work it's very difficult because you have to patch these pieces of landscape back together again and they've all been disturbed by tectonics. In fact it makes the driving difficult as well. Here's a vehicle that's coming up on a fault scarf right here. This is a fault that is separating two different bodies of rock that are not even exposed here. There's just nothing. It's a desert pavement. You'll not find any fossils there. You'll not find any fossils up in the hills where the lava flows are. You eventually won't find any fossils here either. You'll find goat and Kool-Aid and let me introduce you to some of the members of the team to give you a sense of the work that we do. Stan Ambrose is a soil geochemist and archaeologist from the University of Illinois who works on the isotopes of carbon and can tell us what the soil is signaling about how closed or open the environment was at different times in the past. This gentleman down here is the local shake the key off our man the village. This gentleman here is Gidew Aldi Gabriel. He's a geologist from Los Alamos. He's actually a volcanologist and he hasn't yet decided whether or not the following picture is a good day or a bad day in the offer. Fortunately, we haven't faced this yet. This is actually Pinatubo which in terms of the large eruptions in the Ethiopian rift over the last six million years Pinatubo was small. The eruptions in Ethiopia that led to the deposition of these ash horizons which are sometimes several meters thick. These eruptions are measured in terms of cubic kilometers. Imagine a cube a kilometer on each side and tens dozens of cubic kilometers are ejected at one time. This is great for us because the volcanic ash goes everywhere obviously it upsets ecosystems and so forth some of it actually blows out over the Gulf of Aden where we can pick it up in deep sea cores and we can actually use this material it's an interesting material at first it's windblown it ejects sometimes goes stratospheric and in fact can circle the globe but the larger particles fall into local depositories and you can see the shininess the little shiny sparkling points here in the palm of the hand. These are individual glass shards and it turns out that these individual shards of glass each have a peculiar fingerprint in terms of their chemical composition and so Gidea can study the chemical composition of these ashes and link them together by their chemical signature indeed link them even to the Gulf of Aden where these ashes fell on the sea and then fell to the bottom of the sea and we can now extract them with sea cores. Now we're going to go up in the air again because I promise we can't spend very much time in this talk at any one time horizon. I want to give you a series of snapshots through time. This is a view from that same light aircraft over the Bore Peninsula and the man that we initially met out here standing with the rifle over the collectors was standing near the Awash River the Awash River Riverine Forest comes down like this you can see these badlands and you see this spot here this sort of brownish spot that's an off our village and these little whitish dots each one of those is one of those off our houses this kind of gives you scales it's interesting they bring the goats and sheep and cows they take them out to water them at the river and then bring them back at night and put them in the corrals and when you put a lot of animals in the same place for many many nights you end up with a big brown spot on the landscape and you can actually see this on the thematic mapper images from space you can pick these up against what is a really barren landscape which for we paleontologists and archeologists that's great no vegetation means we can see all of these surfaces and by studying these you see the whitish rocks here those are the volcanic ashes that have been erupted and what we're going to do here first is to look at those two and a half million year old deposits those are the ones along the eastern face of the peninsula the reason the peninsula is there in the first place is these tectonic events have lifted these sediments up so they're currently eroding the sediments on top of those are about a million years old called the DACA member we're going to look at a couple fossils from there and then finally we're going to move to these sediments that are up on top of the peninsula the youngest horizons called the Herto member and so we'll be looking at those and concentrating on this period around a hundred and fifty thousand years ago now this is a cover of Time magazine I want to say a couple things about this the hominid fossils themselves get all the glory in this business and even when they're really fragmentary such as this one this in fact is a fossil that was found in those two and a half million year beds just below where that off our man was standing excuse me I want to draw your attention here to what has been for me at least an emptiness since the time that our friend Steve Gould passed away Steve was always a guy that we could count on to step up as he did in this Time magazine article during the Kansas school board controversy and present his unique perspective on the issue of science and religion I'd just like to take a moment and say that that this truly is a colleague who we miss greatly Steven J. Gould the hominids themselves command a lot of the attention but sometimes the more important facts are in the small details in fact as Karen mentioned there's a several spin offs now but a variety of television programs that focus in on those small details are kind of many hour long mystery stories the sort of who done it of modern society well here we're studying people and animals that died two and a half million years ago and this is a jaw bone that we excavated back in 1996 it's a jaw bone of an animal that stood about the size of a will to beast in fact the best characterization of it is that it was a will to beast and when we take a tongues eye view of that lower jaw we see these fine striations striations that can only have been made with these multiple tracks with the edge of a sharp stone and it seems that this will to beast had the tongue cut out of its mouth 2.5 million years ago now that is very important because it is at that time horizon that we see the very earliest human technology and this technology is very rudimentary we recognize it mostly because it shouldn't be there as large clasts of volcanic rock in a fine grain sedimentary environment we can recognize these stone tool cut marks we can collect the stone tools and they're giving us a very consistent picture and the picture includes environment environment here is very difficult to reconstruct that's why we have this large team of people working together Elizabeth Verba, the paleontologist from Yale who studies the bovids can tell us that this kind of organism lives in an open grassland environment dozens of other bovids are collected from the same sediments these hominids were taking sharp edge stone tools into open grassland environments this puny primate with very small front teeth rudimentary stone tools accessing large dead mammals in an open environment this is a Gary Larson cartoon that's was a kind of a response to some earlier anthropology that had been done about the importance of hunting in human evolution and he depicts here early vegetarians returning from the kill and I think it's not a bad characterization of the first portion of the talk in the sense that the hominids we've talked about until now lacked these stone tool technologies but the stone tool technologies afforded them a chance to actually move into a very unusual niche and to move into competition with animals such as these these of course are modern lions there were fossil there were ancient ancestral lions in those days at two and a half million years ago there were saber tooth cats there were very large hyenas but all of a sudden you have a primate exposing itself in these open conditions to those kinds of selective forces and I think that it's no surprise that shortly after that in the fossil record we see several things happening we see an increasing sophistication of these stone tools over the next million years or so and we see hominids for the first time outside of Africa at about 1.8 million years ago and we see a species that by a million years ago we call it Homo erectus and it's expanded its range from the gates of Gibraltar to Beijing to Indonesia from Cape to Cairo very unusual primate and that primate that hominid that creature that is intermediate between the earlier ancestors we've found and the later ones we'll be talking about is called Homo erectus this is Henry Gilbert a graduate student at Berkeley who found this is sort of the paleontologist dream like the hippo mandible except hippos are pretty easy to find they're big not terribly intelligent and they sink into the mud very easily so we get lots of hippos in the fossil record hominids don't share those characteristics so they're very very rare and it's very rare that you find one just eroding out of the surface you hear you see the profile at the top of the head and Henry's holding a piece of the head there we published this a couple years ago it's a very good representative of this species, this widespread species known as Homo erectus now key to this organism's success indeed the reason we're standing here today is this stone tool technology I like to show artists reconstruction sometimes in settings like this just to show you how silly these artists can be let's think for a minute biologically let's think for a minute in terms of Darwinian fitness here how plausible is this before the invention of pants I see from the clock on my wrist that I'm going to get the hook pretty soon but before we do that I wanted to share something with you which is in a sense you've now been introduced to the offer so you know some of the main characters you know the environment a little bit I'd like to share a video with you that was done by, it's a short video kind of a music video we use this kind of as an intermission and I do it to remind the audience that we're all bipeds so I'd like you all to rise please stand up on your two feet and evolve this and we might as well make good use of it here it's also something about human physiology that you get to this point in the lecture and it's a good time to stand up I'd like to take you all now into the offer but in order to do that I couldn't afford it on the NSF budget so if I were to move the offer here I mean I thought about doing this the organizers of the conference don't like this so we'd have to close all the doors and turn the heat up to 110 in the shade and then we'd have to bring, I ordered two dump trucks with some of the finest silt available in Minnesota and we're going to bring the dump trucks in and put very large fans behind them and blow the dust into the room we'll turn off all the lights I've contacted the entomology department they'll be bringing in the scorpion centipedes and malaria mosquitoes the zoology department vipers of various kinds so if you feel something crawling around on the floor you'll know that's what it is these are harsh conditions and all joking aside it is a unique team that goes out into this field every year and makes great sacrifices to make these discoveries and I want to share a little bit of that experience through the videography and music of Rod Paul so if we could go just I won't be saying anything we'll just crank the music up for a short break it reminds me to thank Pat Francik and the crew here who've done an extraordinary job at setting this place up so that we can have this meeting well done I promise that we'd talk about Neanderthals and ever since Neanderthals were found back in the middle of the 1800s people have been debating their place in human evolution since their discovery these have actually become the most abundant form of fossil hominid back not very far actually to the mid 1980s to give a sense of where we've come since the mid 1980s the national geographic magazine decided to do what they call an early man update article and eventually stretched the envelope a long way they had great photography in there from a man named David Brill who currently works with our project but in doing this they undertook to do a family tree of human evolution and the National Geographic particularly in those days was a highly conservative organization and they also did a lot of very good fact checking and so you knew what you read in the National Geographic was accurate it's no longer necessarily the case but in those days they went to anthropologists and not always a good thing to do because anthropologists can't seem to agree on the place of anything in the hominid family tree but that in those days they went back to about 3.5 million years ago where Australopithecus afarensis Lucy and her kin are located subsequent to that and this is still true today and Niles mentioned this yesterday a couple of different lineages appear and subsequently go extinct at about a million years ago in the African record the 2.5 million year time period shown as pretty empty in this phylogeny we've looked at that evidence the meat acquisition and consumption at 2.5 million we've looked at Homo erectus at a million years ago and how that fits in and of course erectus is on this diagram as well but look at the problem they had with Neanderthal if you imagine several anthropologists on this side pushing him in that direction and several anthropologists on this side pushing Neanderthal in that direction some people thought that it should occupy a central position that Neanderthals were ancestors other people thought that Neanderthals were a side branch leading on the one hand to extinction while on the other hand modern humans arose but this time period around 100 to 200 thousand years ago did not have a great deal of fossil evidence and so the National Geographic took the only way out of this disagreement and that is that they brought Neanderthals in just to touch the line see if they moved it off a little bit and if they'd put it a little bit in it would have been an answer National Geographic didn't want to take a position here people would have been upset now when you have that kind of of disagreement among the scientists and even at the National Geographic you can do this which you can compromise or you can look for leadership it's true now also in the 1980s there appeared this magazine cover which was extremely misleading like the other ones that I've shown you in this case suggesting that scientists were actually searching for Adam and Eve actually it was more about what they termed here a controversial theory and actually it wasn't that at all it was some work that had been done largely at the University of California at Berkeley by my late colleague Alan Wilson and a then graduate student named Rebecca Khan what they had done is to look at a particular kind of DNA called mitochondrial DNA that is inherited maternally and they found a couple of surprising things from these studies first of all when they took a sample of pygmy chimpanzee DNA and characterized it they found that pygmy chimpanzees were quite variable in this mitochondrial DNA and they were kind of normal mammals in this regard the abnormal mammal that really stood out in this sense was homo sapiens because no matter where they took the DNA from indigenous people in Alaska South America, Australia Africa, the Far East Europe very small amount of variation that was interesting it suggested that the human species had gone through in geological terms a fairly recent bottleneck and I remember Becky coming to my office in those days saying well what about what does the fossil evidence have to say on this do you see anything like that and I said well I work in Africa and we really don't have much of a fossil record in that key time period that they were thinking through comparisons with other lineages would be approximately 100 to 200 thousand years ago the other interesting thing they found from these genetic studies is that the limited genetic diversity present in the human species was greatest in Africa shown here and this is just the maternal inheritance this unfortunately came to be called Eve in fact every species has a lucky mother it just turns out that our species had a lucky mother that lived only about 100 to 200 thousand years ago what did she look like where did she live what were these people doing these are things that you don't learn from the molecules the molecules can do certain very important things better than anything else and the fossil record can do important things better than anything else so to understand these early African populations that were ancestral to our own species we need a fossil record now I've told you about the offar you understand the place and here's what the camp looked like last December because it's now raining in the highlands unseasonal rains remember yesterday what happened with El Nino in the Galapagos El Nino in the offar you move your tents quickly from the river up to the bank and you don't take any cars across the river so we're completely isolated at this point nothing can come in nothing can leave except on foot until the river goes down and here we have a vehicle crossing the river that's actually not a bad thing these El Nino rains sometimes sweep out over the offar they rain on these barren landscapes and new things come up so although in 1997 we moved into the field because of El Nino when we got there one of the first things we found was this hippopotamus cranium eroding from those sediments at the top of the pile on the peninsula around 150 to 160,000 years ago and a number of stone tools out here in the vicinity stone tools like this that told us we were dealing with fairly advanced technology this is called the Ashulayan a late Ashulayan hand axe we found on the hippopotamus itself when it turned to stone it is as hard as glass almost you can see this chopping mark that had been made by one of these implements about 150, 160,000 years ago we didn't know exactly how old it was at the time and we did know that it was in that time period that the geneticists were saying was critically important in terms of the origins of our species so we were very interested in finding remains of hominids but by this time hominids are fairly advanced we know that ever since a million years ago from that Homo erectus fossil we found so we had to go out and find a fossil and what I thought I'd do here today is we do find fossils and a lot of fossils and you might be in a situation sometime in the future where you might want to go out and find fossils or you'd be in a bad lands and you're wondering what's that shiny thing up on the ground and this is not a bad setting we have lights and the key to this is you walk toward the sun alright at first that seems kind of countering to you walking toward the sun we're kind of blinded by the lights we can't really see the fossils that's why you need one of these you really need one of these if you're a white bald guy out in the offer see that's much better I can see you all in the audience now and you know what I see I see the reflections of the eyeglasses of all of the people there the light but down on the floor I see all kinds of shiny objects this is really good because most of the fossils you find in the field are silica replaced and they shine more than the background so you walk to the sun get a visor on and look for the reflected light that's how you find these fossils now you're going to need that you'll need a little bit more in this process though so let's see what what a trained paleontologist can do is finding things in the field he's a graduate student of mine at Berkeley he has found some of these shiny objects on the ground he's pin flagged them because he's recognized the one that was about the size of a dollar silver dollar this was a piece of the parietal of a hominid and so when we started to investigate this brushing aside we found even larger pieces a very tight scatter and when we brushed around we saw the outline of what the excavation looked like see the broken pieces of vault but there's also, it's very difficult to see here the outline of a hominid cranium embedded in this sand right at the surface I'm going to go back a minute remember the off-ar villages this is Herto Village it's abandoned no brown spot good news for the paleontologist if we hadn't been there at this time in this place with an individual who recognized this small broken piece of fossil what you're about to see would have been lost forever because these people moved in a month later with all of their cattle and as the cattle crossed this surface it would have destroyed that fossil well it would have broken it we probably wouldn't have found as much as we were able to find but we extracted it this way we covered it with a plaster bandage excavated underneath flipped it over and now we're going to excavate the landfill from the bottom of this we're going to dig into that block that's what the next slide shows us sweeping the sand away, you can see the bone starting to emerge here and then a cranium starting to emerge and finally when all is said and done after a lot of hardening with preservative because it's extremely soft if you just take one of the grass roots and pull it out you'll pull a whole side of the face away from the sand grain at a time over months and finally the product that we got is this it's an adult male individual we know this from its robusticity very important anatomically and we will come back to that I want to start though by talking about what we found nearby in fact the same day just at the time that David was finding that a Turkish colleague was finding these pieces and they're just scattered this one got out onto the surface probably centuries ago and so all we got were the broken pieces these pieces had some very interesting features though again marks made on the bone when the bone was fresh scraping marks, cut marks very unusual marks and when you find those when you find those kinds of things in the fossil record if you're an anthropologist I suppose your mind runs to your introductory textbook this is of course a Hollywood version of cannibalism but there are other things that go on in anthropology including many different kinds of religion and many of the topics we talked about yesterday I think are uniquely informed by anthropology and uniquely informed by a cross-cultural series of comparisons in Papua New Guinea the crania of ancestors are kept around they're displayed on poles they're used for other purposes they're often decorated all part of a ritual that begins upon the death of the individual a series of mortuary practices that involve cannibalism and involved until fairly recently the transmission of a prion disease known as Kuru very very interesting anthropological story and let me tell you what happened next in the offar Dr. Burhani had been trapped on the highlands when we were finding these other fossils because it had rained so much he couldn't get back out to the field site when he finally arrived he got there and he said you guys have found everything and we said nah there's no way and actually he walked over very close to the adult human and found this piece first on the ground picked it up and recognized that it was a hominid it was a six to seven year old child's cranial vault this fossil had completely eroded out and it shattered in pieces on the surface we got the material on the surface through a sieve to recover all of the pieces we recovered over 200 pieces of this cranium now there's a myth in paleoanthropology that it takes some kind of a special liking for puzzles or something like that it's a three dimensional puzzle and extremely challenging in fact that is a myth if you're a skilled anatomist you are able to use all of the anatomical clues and actually put the cranium back together again this is Dr. Burhani putting it back together again and he ended up with this is the orbit the eye socket the parietal bone and you see this kind of polish this shine on the top of the cranium what we found on the cranial base were a series of very fine cut marks this bone is one of the hardest fossils one of the most glass like fossils that we've ever found in the study area there's no way you can do this even with a steel tool to make this kind of a scratch that scratch had to have been made when the bone was fresh and the only way that could have happened is with some other hominid after the death of the child removing all of the soft tissue from the cranial base and part of the cranial base was also broken away and we saw the polish up on the sides so what's going on here well cold case this is Herto the village is off to the right that's where the intact adult cranium was found the adult from right there hundreds of fossils and artifacts collected from this surface which they're digging into the horizon that produced these fossils right here and not a single bone from the rest of the body of these three individuals and of course each one of these individuals had 204 or 5 other bones in the body none of these were found we don't know what happened to the rest of the body all we know is that there is some form of a mortuary practice under way here the geologist in the meantime while this work of reconstruction and analysis was going on we're busy tracing this layer to other layers correlating it doing the volcanic dating work to establish the age of this between 155 and 160,000 years ago now I want to turn back from the behavior back to the anatomy because I'm going to give one last anatomy anatomy lesson here this has to do with modern human cranial form this is a man from New Guinea who's using one of these ancestral crania as a pillow in this particular case imparting a polish on it but when you look at a modern human cranial vault you can actually do this by looking at the person sitting in front of you they should have the greatest breadth on their parietals very high up on the vault if there's a person sitting in front of you that has the breadth way low down please bring that to our attention at the end of the lecture another characteristic feature of the human face is it has this canine fossa just in this region it's very visible on the face very distinctive human face a high rounded vault a fairly vertical forehead so these are the key anatomical traits we look at when we're asking about the origin of Homo sapiens and these are six views of this cranium and we see the greatest breadth is up here high on the vault across the parietals we see a face that is configured as your face or my face for a large and robust individual a little bit different from modern humans how is it different in the direction of earlier ancestors in Africa more robusticity in the back and the front of the vault now this man lived on the lake shore of a tropical lake in Africa at 160,000 years ago what was happening 160,000 years ago in Europe that was happening paraglacial conditions and the inhabitants of Europe starting about 400,000 years ago evolved some specializations that ultimately ended up with their being called Neanderthals they are distinctively different and probably owe their unique morphology to that paraglacial environment you can get this kind of stuff at your local newsstand but I just want to point out why you should be skeptical of this because actually these cavemen in Europe did not look like Elvis Elvis has the greatest cranial breadth high up on his cranium he has a canine fossa here someone has put Elvis's head onto the body of a Neanderthal this is what a Neanderthal looks like greatest cranial breadth down here in the canine fossa we recognize these creatures the Neanderthals now starting at, as I said, around 400,000 years ago this is Jay Maternas' reconstruction from many years ago in the scientific American probably the most accurate restoration that's ever been done of a Neanderthal what about modern people well all of them share that cranial anatomy that we see really first expressed in the hereto specimens in Homo sapiens at 160,000 years ago individuals who lived at the right time and in the right place to be the ancestors the genetics points to in that part of the world so to review that sort of African centered human evolutionary story we go back to 5 or 6 million years ago when we parted company with the line that led to the modern chimpanzees we can follow a chain of ancestors we see some go off as side branches and go extinct we end up with Homo sapiens at 160,000 years ago in the time frame that all of this mitochondrial data these are the original data from Con and Wilson showing Africans throughout the human mitochondrial tree and suggesting an African source for our own species and so 160,000 years ago to make a long story short we look something like this this is Jay Maternas' reconstruction of this hereto man at 160,000 so you can see that in this exercise we have a unique possibility in the middle hour wash we have a unique record and by using this unique record of this study area we've now tested in one place all of the models that say we should find anatomically modern people all the way back to an abrupt origin in the oldest sediments we can find I've shown you the results of the test all of those models fail the more deeply we look back into the six million year record of accumulated sediments the more anatomically and behaviorally remote these ancestors are and that's true whether we're talking about the ancestors of aardvarks or bats or zebras or humans or any of the other dozens of mammalian lineages whose roots can now be traced to this record Darwin's 19th century predictions about human evolution have led to research and to results that show how the living world was articulated by evolution and how humans were part of that process there's a lot more to learn about how that happened but there's already plenty of evidence to show that it did happen thank you very much