What a piece of work is man, said Shakespeare. One of the more famous quotes from his play. Pretty lofty statement about humans. So, even way back when Shakespeare was writing, it was certainly apparent that humans have some special features. And we talked a little bit about them last time, I want to go through some additional things today. We'll see a video clip featuring Alan Alda and some of the research that's going on. Back in Shakespeare's day, we didn't know much about humans. Except that we were a pretty cool critter. But we didn't really know anything about how the brain works in any detail. We didn't have any ideas that we were the result of a long process of evolution that we had ancient ancestors, all kinds of things like that. And one of the fears that a lot of people have is that when you know about this stuff, when you can look at the data and the science, and the technology, and look into all of these aspects of humans, that you lose that kind of magic, most scientists don't think so. Darwin saw this, as he stated it was the grandeur in the scheme. And most scientists that I know and most scientists that I have read about, see this deeper understanding of the workings of humans and where we came from as something that is nobbling and makes that seem all the more true. If you go to a good natural history museum, you will be able, in most cases, to see a display case, something like that, that is filled with skulls and skeletons and usually arranged in such a way as to indicate a timeline. These are timelines that are almost impossible for us to imagine because they involve thousands, tens of thousands, millions. Sometimes even billions of years to see the sequence of all of these events and there are a lot of people who don't want to see that. They are sometimes called denialists and they have some pretty good reasons in their own little belief system. And they say well, these funny shaped skulls and bones that we see were probably just cripples. They were people who were disfigured in some way. So they probably died, or were killed, because they were different, and that's why we find these funny looking human skulls and skeletons. And they say there are too many gaps in the record. Where are all the missing links? Well that might have been a fair question when we discovered the first couple of skulls. But we have probably thousands, I don't know how many skulls we have. But we have lots and lots of skulls that provide a pretty good record. Of course they're years missing, they're probably tens of thousands of years missing in some cases and you have to fill in a lot of gaps. But it takes a pretty hard core skeptic to think that the gaps have not been filled in some way or other. The denialists, in many cases, don't like the idea of an old Earth. And don't believe the carbon dating methods, and the other methods that are used to calculate the approximate age of these skulls. And you will have a skull that one scientist says is 250 million years old. And then another scientist comes along and says no, I think it's 300 million years old. And the denialists will say well, see they missed it by 50 million years. We can't trust it so we don't even know that it's old. It might be something else. And that the remains that are found may have been brought there in some way by accident, rather than being the location of a village or something like that. But we are continuing and accelerating the collection of these data, and it's providing an evermore rich understanding of where we came from and what our history is, and in the same way that we are interested in our personal histories. Now you guys are probably not as interested in your personal history as Professor Ogilvie and I are. This seems to be something that happens a little bit later in life. When you start to look back at the pictures of your grandparents and your great-grandparents and you wonder, what did they do for a living, and how did they get over here to the United States, and so on and so forth. And in some sense, this is just an extension of this. How did human beings end up being on the North American continent. That's just a longer family history than we're used to dealing with. I want to spend some time today in the main feature of the video clip that we're seeing is about the Neanderthals. I think I gave you a quote from a current neuroscientist named James Caillat a while back that goes something like this. He said that, one of our ancient ancestors who behaved more or less, like we do survived and reproduced more successfully than some closely related creature. And the one that I acted more or less like we do, became our ancestors and the other group became extinct. So, what we're going to see here is a group of Neanderthals who went up on this branch and became extinct and modern humans who followed this branch and are still surviving quite nicely today, thank you. We ought to be a little bit cautious about labeling the Neanderthals at as a unsuccessful because they survived for over 200,000 years. Now, humans like us have been around for about 40,000 years. So we still have a long way to go. And the more pessimistic amongst us like Professor Ogilvie and myself think there's a pretty good chance that we're going to blow ourselves off the face of the earth sometime within the next 160,000 years. And if we do that, whatever is left could label us as being less successful than the Neanderthals. But we don't need to worry about that today. The Neanderthals made simple stone axes. They worked. They just continued using them instead of trying to make new and better stones and axes. They lived in caves, at least some of them did. And a lot of caves of early humans have drawings and paintings and other kinds of ornamentation inside the caves. The Neanderthals apparently never did that, at least none has been found. So they just led simple lives for a long time. Interestingly enough remember what we talked about last time, our long childhood. The neanderthals did not have a long childhood. They grew up within about 6 years, instead of reaching physical maturity at about 18 or 20 years. And that may be one of the reasons why they remained unchanged for such a long period of time. And if you look at the skulls here, they weren't very cute. They didn't maintain their juvenile features into adulthood. So this is a modern human skull and the modern human skull kind of fills in the back here and makes a nice brain case that's still relatively round whereas the structures of the Neanderthal as they grew older and matured. It was the facial structure that became longer and so their chin was protruding more. So they were missing a couple of those evolutionary features that we talked about last time. I was imagining in the early days when there may have modern humans and Neanderthals surviving at the same time, imagining this Neanderthal who walks into a sapien's bar and the bartender says why the long face? [LAUGH] Anyway. Let's watch. >> One group of descendents stayed behind in Africa. But another group headed north and over hundred of thousands of years, eventually made their way to Europe, where they evolved into what today we call the Neanderthals. I'm back in the hills of southwestern France, heading for one of the classic Neanderthal archaeological sites. [MUSIC] The question on my mind is this. We know that those of us who stayed behind in Africa somehow some when acquired the modern human mind, the human spark. Our existence proves it. >> Oh hi, how are you? >> So then what was it about our Neanderthal cousins that prevented them from evolving the spark? What made them different? >> Welcome to Roc De Marsal. >> The cave of Roc De Marsal sheltered Neandtherals from just over 80,000 years ago until the roof collapsed some 40,000 years ago. Still here, as the team patiently digs and brushes, is the debris of everyday life including stone tools, and the remains of the animals butchered by those tools. >> Anybody got any shots? >> I've got one. [MUSIC] As in most modern archaeological excavations, the location of every item found is plotted in three dimensions with the help of a laser and it's details entered into a database. >> And that's G17 59 10. >> So far the team has logged some 17,000 stone tools and the same number of animal bones from just this small shelter. And from details like this the archaeologists are building a picture of Neanderthal life that seems strikingly similar to the life of their ancestors in Africa. For generation after generation, they stuck to the same way of doing things. >> When you look at the enormity of time represented in these early industries that is times of Neanderthals, it's mind blowing. Hundreds thousands of years and you see the same sorts of patterns repeated over and over and over again. You don't see a clear evolution of traits over and over again. >> So they weren't very innovative. >> Yeah, in a sense. But the thing is, too, I would look at it more as they were very adept at adapting what they do have to the local situations, right. >> I would say they were flexible, but not innovative. They had their toolkit, they had their solutions, and they picked from that tool kit over and over and over, for hundreds of thousands of years from that, basically, the same took kit. >> Just as we had with the hand axe from Kenya, we asked John Shade to make the basic tool from the Neanderthals tool kit. Remarkably, the two are almost identical. [MUSIC] The technique for making it became more sophisticated, Neanderthals started using a bone or antler hammer to make the edges thinner and sharper. But the tool itself changed very little in the 1.6 million years since the common ancestor we shared with Neanderthals first figured out how to make it. [MUSIC] Even after arriving in Europe, Neanderthals stuck to the old ways. >> It's still striking for me to try to comprehend that they went so many thousands of years pretty much not changing the way they did things. >> I know. >> How many generations we've got of them. >> 40,000 years if you want to figure that's the occupation of the cave, would be 2000 generations. >> 2000 generations. >> Dennis says great set [CROSSTALK] [LAUGH] >> 2000 great grandfathers and mothers. [LAUGH] >> 2000 great grandfathers and grandmothers. It's amazing. >> That's amazing. >> It really is. >> And yet that's a long time that they survived. [MUSIC] >> Below this cave was occupied for 40,000 years. Neanderthals as a species survived for some 200,000 years, all the while with very little change in their way of life as revealed by the debris they left behind. But today science is gaining unprecedented insights into that way of life thanks to the remains of the Neanderthals themselves. Like this fossilized skeleton of a child found in a pit at Roc de Marsal. The most ambitious approach to Neanderthals forensics is taking place in Leipzig, Germany at the Max Planck Institute for Evolutionary Anthropology. Here scientists from a range of disciplines are looking for the human spark by comparing us with both our living relatives, like chimpanzees and other apes, and with our extinct relatives like the Neanderthals to try to pin down the crucial differences. >> Subtle, not so subtle. >> Why do we care so much about the difference between us and the Neanderthals? Is it a sentimental difference, or is it going to really teach us something about who we are, how we're made, what makes us human? >> I think it can potentially teach us a lot. I mean, it's after all we fully modern humans are really unique in this thing that has spread over the world, colonized all parts of the planet become really dominant in the ecosystem that the other early forms of humans didn't do. They spread pretty much like other big mammals, like wolves or something like that. It's something here in our behavior that's very unique and to get behind that, what is that thing that makes that possible? I think that's one of the more fundamental questions that I can think of that I would really like to find out. Svante Pavo heads a project that aims to decipher the entire genetic code of the Neanderthals so that it can be directly compared with our own. Dressed from head to foot in protective clothing, I got to watch how researcher Adrian Brigs drills into Neanderthal bones in search of the tiny fragments of DNA that have survived there. [SOUND] You seem to be taking enormous precautions against contamination. Why is that? >> Well, there's very small amounts of DNA left in these bones after so many years in the ground. The amount of DNA we would normally give off by shedding skin cells for example Is the same or more, the amount of the actual DNA from the Neanderthal. So in order to really reduce that background DNA, then we really have to be as careful as possible. And even then, you have to really carefully analyze your results to be sure that you haven't just sequenced yourself. >> The Max Planck Team recently completed the first rough draft of the Neanderthal genome. The headline news is that there is little evidence our ancestors and Neanderthals mated when they met or at least that they produced any offspring. But so far there's no single genetic smoking gun to explain why the spark failed to ignite in Neanderthals in large part because the genetic differences between us and them are turning out to be very, very small. >> But that small difference between us could be crucial. It could mean a great deal about language and thought processes and that kind of thing. >> Yeah. So the dream is, of course, to find those few changes that's hiding there but are crucial. >> Fulfilling that dream will take more time. But meanwhile, the bones are revealing another crucial difference between them and us, what Neanderthals ate. In another lab here at the Max Planck Institute, protein extracted from Neanderthal bones is wrapped in little lead packets ready to be analyzed. The analysis of the isotopes of carbon and nitrogen reveals whether the bone protein came from meat, fish, or plants. >> We've looked at Neanderthals maybe ten of them now from about over one hundred thousand years and what's been surprising is in every case the isotope value seemed to show that all of their protein was from animal protein. We don't find evidence that there was any significant amount of plant foods in their diet. It seems strange that over this long period of time, they seem to be doing the same thing, that they were getting almost all of their protein from animal protein. >> And when Mike Richards says animal protein, he means meat protein. >> The Neanderthals interestingly don't seem to have had any fish. Even when they lived sort of close to the coast but mostly when lived inland along these big rivers in Europe that have lots of sturgeon for example, they don't seem to be hunting them at all. >> Does anybody have an idea why that would be so? It was there, was available. >> Yeah I think that actually Neanderthals are very successful. I mean they survived much longer than us in Europe and actually their adaptation didn't seem to change very much over the sort of 200,000 years they were in Europe. So it was very successful adaptation so why would you change it and why do something new. And actually I think conceptually going from hunting large animals and subsisting off that to getting something out of the river, small little fish and small birds, and small game, it's something the Neanderthals don't seem to have ever really done. >> In the foothills of the Alps in the French city of Grenoble is located the most dramatic of the new scientific studies aimed squarely at answering this central mystery. Why the Neanderthals seemed incapable of changing the way of life they inherited from their African ancestors. This is the world's biggest x-ray machine, the European Syncrotron Radiation Facility. Brought here from Belgium to have its teeth x-rayed is the upper jaw of the Neanderthal child. [MUSIC] [SOUND] A laser is used to line up the x-ray beam which is millions of times more powerful than that from the machine in your dentist's office. [SOUND] Also here today to have its teeth x-rayed is the skull of the young Neanderthal found originally in France. [SOUND] The teeth of both specimens are 50000 years old, yet their condition would make a modern dentist proud. >> When we're growing and developing our teeth we're pumping so much mineral into them that they're almost a 100% mineralized already. So they're almost fossils in our mouths as we're living today. >> And they're fossils with a built in calendar. Teeth lay down a new layer of enamel every day they're growing, so Tanya Smith can literally count the days of the Neanderthal children's lives. >> Effectively, the total period of time you're growing your teeth gives you a good proxy for how long your childhood is. >> This Neanderthal child was thought to be about six or seven years old but the growth lines in its teeth suggest that it was in fact younger when it died, meaning that it developed faster after birth than children today. Today's newborns are beginning a longer childhood than that of any other animal. We're born with immature brains in part because human anatomy limits the size of a new born's head. As a result, much of the brain's growth takes place after birth. Here's how a modern infant's skull enlarges from birth to adulthood with most of the growth in the brain case. In contrast, the skull of one of our early ape like ancestors grew mainly in the face and jaw. So the brains of today's children are literally created out in the world. They have 17 or 18 years to mature and absorb the culture and language of the people around them. This long childhood could be a vital component of the human spark, of what makes us unique. [MUSIC] Neanderthal children, by contrast, seem to have grown up more quickly, with less time to learn the ways of their elders. Less time, perhaps, to rebel against those ways and experiment with new ones, before themselves being thrust into adulthood. So the picture that's emerging of the Neanderthals who lived here at Roc de Marsal, and throughout Europe, for some 200,000 years, is of a people with remarkable tenacity. But an equally remarkable blindness to change. And, lacking the human spark, it seems they went forth but did little multiplying. How many Neanderthals are we talking about? >> [LAUGH] >> How many do you think were like, around all over Europe? Say, 80,000 years ago. >> Few thousand, 10,000, 20,000. >> I don't think it was that many. Well, I don't know that number, but I think it wasn't. >> A small amount of observations. I think it was probably a lot fewer than we think. >> 10 or 20,000 people, the population of a small modern town, probably in bands of 20 or 30. That may be 500 little groups of Neanderthals at any one time spread out over the whole of Europe. Meanwhile, those humans who stayed behind in Africa continued to evolve from our common ancestor but along a very different path from that of our Neanderthal cousins.