Missing Links....Homo Erectus (1080 HD)

- Over a million years ago in remote caves in China and Indonesia, our prehistoric ancestors mastered fire, shaped stone tools, and faced ferocious predators such as sabertooth cave lions. Until recently, these ancient Asians were have thought to become a dead end branch of the human tree. Now, controversial theories have disputed the conventional picture of modern man's origins in Africa.

[PaleoWorld: Missing Links]

30 miles south of Beijing, in China's most famous archaeological site, Zhoukoudian, or Dragon Bone Hill, in this cave, dozens of extraordinary skulls and bones have been unearthed, dating back a million years to a time when our ancestors were not yet fully human. Scientists call them Homo erectus, upright man. Although Homo erectus has also been found in Africa and Europe, anthropologists have fiercely debated, for almost a century, where these early Asians came from and whether they belong on our modern family tree.

But they do know what Homo erectus looked like based on the skulls that have been found. Their eyes were set far apart under a massive brow ridge. Attached to the brow were thick muscles for chewing, which moved the formidable jaw. The size of the jaw and the teeth, 25% bigger than our own, reveal that Homo erectus probably relied on their teeth as tools to grip and pull objects such as animal hides. Simple stone tools showed that Homo erectus was also intelligent. Skulls vary enormously in size, falling in the range of humans today. What ideas were kindled in the mind of these rugged-looking forbearers? What sort of world did they face in the China of half a million years ago?

Back then, much of the Earth's climate was colder and drier.

[500 thousand years ago, 250 thousand years ago, PRESENT]

The seas dropped by up to 300 feet, exposing land bridges like the Sunda Self, that linked the Indonesian Islands to mainland Asia. Much of southern Asia was covered in tropical rainforest. The discovery of extinct elephants throughout Indonesia indicate there were open areas where large animals could graze. Stone tools found with Homo erectus suggest he was a hunter and would have been attracted to big game. But he faced stiff competition. Not only were there elephants, bears, leopards, tigers, and rhinos, but also sabertooth cats, ferocious cave lions with huge teeth used to tear its prey apart. Many erectus bones from Asian cave sites bare gnawing marks, suggesting their owners were dragged to the cave as victims of these fierce predators.

But where did these primitive humans come from? Did they originate in Asia or migrate from somewhere else? The trail of clues began in Indonesia where the very first skull of Homo erectus was found by an adventurous Dutch anatomist, Eugene Dubois, back in 1891. Prospecting for fossils along the banks of Java's Solo River, Dubois unearthed a thick skull cap which he was convinced belonged to a primitive human. At first, his finds were ridiculed, so he hid the bones under the floorboards of his home in Holland. In 1936, German Anthropologist Ralph von Koenigswald visited Dubois in Holland, examined the fossils, and decided they were authentic. Von Koenigswald returned to Java the following year determined to find a well-preserved Homo erectus skull, and he succeeded. This time, nobody doubted that this rugged skull, with its beetle brows and massive jaw, belonged on the human family tree. Other skulls eventually surfaced in Europe and Africa.

The most spectacular was on the shore of Kenya's Lake Turkana. On a broiling August afternoon in 1984, renowned fossil hunter Kamoya Kimeu was out prospecting when he spotted a dark brown fragment of skull. It took five years for a digging team to unearth one tiny fragment after another, but eventually they assembled a unique find, a nearly complete Homo erectus skeleton. Dubbed Turkana Boy, he stood about five feet, four inches tall. Yet surprisingly, he was still only 12 years old when he died. The boy's tall, athletic build is significant according to leading Homo erectus scholar, Philip Rightmire.

- That particular boy weighed perhaps 68 kilos if he had been able to grow up. That's 150 pounds. Perhaps a good, round average for Homo erectus in East Africa was closer to 58 kilos, or about 130 pounds. They were tall people also, certainly quite comparable in those respects, to us, to modern humans. Large body size would have conferred to an advantage on Homo erectus in that larger people are simply able to cover more territory. Larger primates, larger mammals in comparison to smaller ones, usually behave that way, simply cover more territory in search of food. It's likely that Homo erectus was also engaging in more hunting and consuming more meat than its predecessors had done. Meat is a highly caloric food. Homo erectus would have been able to meet its energy needs much more efficiently if it were doing some hunting on a regular, more systematic basis than had been done before.

- Archaeologists think Homo erectus ate more meat because they found the first well-made stone tools, ideal for butchering meat, at erectus sites in Africa. Once early humans knew how to make efficient tools and learned how to control fire, they were ready to leave their African cradle and colonize the rest of the world, or so archaeologists have always assumed.

The conventional view is that Homo erectus originated in Africa two million years ago. They were the first humans to leave the continent, spreading gradually into the Middle East, Europe, and Asia. But in 1994, a stunning series of discoveries threw these old ideas open to question and raised a dramatic new possibility about Asia's earliest humans.

The mystery of Asia's earliest humans first emerged at the Zhoukoudian caves near Beijing in the 1920s. Here emerged the fossils that quickly became celebrated as Peking Man, even though many of the bones actually belonged to women and children. Archaeologist Russell Ciochon specialized in Asian pre-history.

- When the first skull of Peking Man was discovered in 1929, it generated banner headlines in newspapers around the world.

[Peking Man ranked as oldest Human. Scientists call fossil nearest approach to missing link yet discovered. Lived a million years ago. Remains regarded as important proof that human life evolved from lower form.]

Because for the first time, we had truly early man in China. Earlier finds had been made in Java, but this was far north, this was in a cave context, and this also contained artifactual evidence, stone tools. None of those events happened with the finds in Java. This is what made this site so significant.

- One discovery created a special sensation: the evidence that they had used fire.

- Thick ash layers at the site of Zhoukoudian indicate that Peking Man had developed the use of fire. The use of fire was an important cultural hallmark in human evolution. It allowed the exploitation of temperate environments. The use of fire, together with a varied tool kit made up of hammer stones, choppers, points, and scrapers, allowed Peking Man to live in a much colder environment than any hominid had before.

- Another sensation was created by the theory that the bones found in the caves were the result of cannibal feasts.

- The idea of cannibalism at Zhoukoudian was first proposed by the famous German anatomist, Franz Weidenreich, in 1940. Weidenreich couldn't explain how the bones of Peking Man had gotten into the cave. In addition, upon studying those remains, he also was puzzled by the fact that there was a disproportionate number of skull remains to limb bone remains. He came up with the idea that cannibalism was responsible for this occurrence. Today we know there are natural occurring agents that could have brought the bones into the caves, such as porcupines or large carnivores that made layers in caves. And we can also analyze the bones of Peking Man for cut marks, which would have been present if cannibalism had occurred. So the issue of cannibalism and Peking Man at Zhoukoudian is now dead.

- Digging at Zhoukoudian continued for over a decade from the 1920s to the 1930s. When the Japanese invaded China, the dig's director, Franz Weidenreich decided he would leave for America and take the fossils with him. The fossils arrived at the port Qinhuangdao on December 7th, 1941, the day the Japanese bombed Pearl Harbor. Casualties of war, the fossils mysteriously vanished. They were never seen again. But Weidenreich had the foresight to make plastic casts, which survived: 14 skulls, 15 lower jaws, and more than 200 isolated teeth, along with over 100,000 simple, stone tools.

- And we have an extensive cultural record consisting of scrapers, such as this one here, which was likely used to scrape out the inside of hides, and choppers, such as this one here, which was used for digging. All of these cultural remains and fossil remains occur throughout the deposits at Zhoukoudian. Dates of these deposits now indicate that Homo erectus spanned the time range from 400,000 years ago to 700,000 years ago at this important site.

- Important as the Zhoukoudian fossils are, they are not the oldest Homo erectus fossils found in Asia. The quest to discover an older site led Russell Ciochon and his colleagues to organize an expedition in 1991 to a remote part of Sichuan Province. Probing a rocky hillside overlooking the Yangtze River, the team began digging inside an ancient, collapsed cavern known as the Longgupo Cave. Eventually, they unearthed stone tools, extinct animal bones, and the lower half of a human jaw. Recently these finds were dated to a staggering 1.9 million years, as old as the earliest known Homo erectus finds in Africa.

Then in 1994, bones from Java triggered headlines around the world. One skull from Java proved to be 1,750,000 years old, while the others were both over a million and a half. Again, the implications were shocking. Erectus in Indonesia was as ancient as any erectus in Africa. These discoveries led Ciochon to a radical new theory.

- Now, what does this mean? If we want to take it in the perspective of these different hypotheses, we might argue that Homo erectus could have evolved in Asia and spread back into Africa, in a sense, which would challenge all of the conventional wisdom on the subject. By this I mean maybe the ancestor of erectus spread out of Africa two and a half million years ago, populated the rest of the Old World, and then was subsequently reintroduced back into Africa at 1.7. This is a rather radical interpretation, but it is certainly a plausible one given the new dates in Asia.

- In fact, the new Asian dates stir up many provocative theories and questions. If Homo erectus reached China nearly two million years ago, did they evolve into us, Homo sapiens, or was erectus in Asia a dead end and replaced by a second wave out of Africa, this time fully modern people, the ancestors of China's present population? ... led to one of archaeology's fiercest debates.

Half a million years ago, Homo erectus lived in these caves near Beijing, sharing the valley below with deer, horses, elephants, and cave lions. Today, fossil casts of so-called Peking Man are kept in the local museum where anthropologist Russell Ciochon compares the skulls of these ancient humans to our own.

- Here in front of us we have a typical skull of Homo erectus from Zhoukoudian. You can see features that are distinctive. It has a very projecting brow ridge, the forehead slopes quite severely back, and it has a nuchal crest at the back. The skull is also flattened where it is wider at the base and narrow at the top. These features are in striking contrast to what we see in modern humans. In addition to the morphological features of the skull, it has a brain size, or cranial capacity, roughly two-thirds that of modern humans.

- At first glance, one is struck by Peking Man's primitive appearance. His thick brow ridges and massive jaw indicates that he's still relying on his teeth, not refined tools. Can it really be true that Homo erectus belongs to our family tree?

It's a tantalizing question, and the evidence of Zhoukoudian reinforces the mystery. At one of the caves, skulls were found dating to relatively recent times, just 30,000 years ago. The bones belonged to Ice Age hunters who probably spent the winters sheltering in the caves. Are they the direct descendants of Peking Man and the ancestors of the modern Chinese? Physically identical to modern humans, they were definitely Homo sapiens. But did another human branch leave Africa a second time and lead to the population we see in Asia today?

In the 1980s, an ingenious technique was developed to trace the genetic history of the world's populations. It involved sampling the genetic material, known as mitochondrial DNA, passed down only through the female line. The results showed that all modern humans are descended from an ancestral eve, a hypothetical mother of us all who lived in Africa some 200,000 to 100,000 years ago. The theory caused a sensation. Recently, major flaws were exposed in the DNA Eve Theory, yet archaeologists such as Philip Rightmire are still convinced that the fossil evidence can only be explained by a great migration of modern humans out of Africa 100,000 years ago.

- Certainly some of the best evidence, as far as modern human origins are concerned, comes from Africa, particularly from the southern part of Africa. I have in mind a cave called Klasies River Mouth on the coast of South Africa. Klasies has yielded a number of human fragments. Unfortunately the bones are rather badly broken up. There are mandibles with teeth, bits of face, bits of skull vault, some limb bones also. These materials, insofar as we can check them, are essentially modern in their anatomy, hardly distinct from ourselves. The important point here concerns the age. Klasies has been well dated at this point through a number of lines of evidence. The first occupation at Klasies River Mouth dates right back to more than 100,000 years ago. People were resident in the cave for a time after that. This, to my mind, constitutes some of the strongest evidence we have pointing to an African origin for modern people.

Rightmire and others think that modern humans spread out of Africa 100,000 years ago and that their superior intelligence and technology drove erectus and its descendants in Europe and Asia into oblivion.

But these to researchers disagree. Milford Wolpoff of the University of Michigan and Alan Thorne of Australia National University are longtime collaborators. For years they've taken a maverick position on the origin of modern humans. They deny the conventional out of Africa theory and argue that modern Asians evolved in a smooth, unbroken line from their ancient roots.

- Now all of this took place with evolution that was within East Asia. There's no evidence at all of some new set of people coming in and replacing this whole sequence or even changing it. It is continuous. It comes up to people in Java who've got brain cases that are in the modern range, these people are just as smart as you or me, on into Australia and on into modern people and in East Asia the same thing. Now it's a continuous evolution. It's not broken. Once people leave Africa, we don't need a second movement out of Africa. These people are evolving to modernity all by themselves in the sense that there's a local regional group. Of course their in contact with the rest of the human world, but we don't need anybody to replace them, because they're heading in the modern direction anyway. And that's regional continuity. Put this into several places, East Asia, Southeast Asia, Europe, and in Africa, and you've got multi-regional evolution.

Thorne's collaborator, Milford Wolpoff, claims that the evidence from China is particularly strong in their favor.

- Here's the earliest specimen we know of from China. It's more than a million years old from a site called Lantium. It's an upper jaw, just like I'm showing on my face, teeth, and a piece of cheek. And what you can see here if you look carefully is that the face is flat across the teeth, and the face is flat where the cheek comes of the face, and it's very anterior, very much like the Chinese today. We can find that same characteristic here in this woman from Zhoukoudian at about half the age, about 500,000 years. So what this shows is that the roots of the modern North Asians are found in people living in Asia as long ago as a million years.

- But many, including Rightmire, disagree with Wolpoff's view that the ancient fossil skulls have characteristics resembling modern Asian faces today.

- There are a number of such characters which are sited in support of regional continuity in China. The problem is that a number of these characters are distributed into other populations spread all across the Old World. They are not limited to the Far East, certainly not just to China. The flattening of the nasal saddle, for example, actually reached their highest frequencies in African populations, well outside of the Far East. Here again, there's a pattern, but it's not the pattern that one would expect to find in support of regional continuity.

- For Rightmire, the fossil bones suggest that Homo erectus in China became isolated, a dead end outside the mainstream of human evolution, an archaic form of human swept aside by the spread of modern man during the last Ice Age. With so few fossils discovered over such an immense span of time, it's not surprising the experts can build conflicting visions of our human past.

- This is all Homo sapiens. I don't think we need Homo erectus anymore, and it would help us to see our evolution if we called them all Homo erectus. So for me, only one species of human ever leaves Africa, and that's us. That's Homo sapiens.

- I'd be quite happy to get rid of the name Homo erectus. It now has become a name that doesn't have anything that it clearly refers to. The fact is that once humans appeared as homo, as Homo sapiens, they've been human ever since, and I think we could show that by calling them Homo sapiens from the very beginning, some two million years ago.

- If Wolpoff and Thorne are right, it's extraordinary to think we can trace or origins back directly to those primitive-looking cave dwellers who had to content with sabertooth cats. If they're wrong and the ancient cave dwellers were replaced by a second wave of humans from Africa, then Homo erectus went the way of the sabertooth cats, pushed into extinction after they had survived resourcefully, generation after generation, for millions of years. Whichever theory turns out to be correct, both represent a powerful evolutionary drama buried in our distant human past.

[Narrator: Ben Gazzara]

[Producer: Tom Haughton, Greg Francis]

[Director: Bertrand Morin]

[Writers: George Bledsoe]

[Story Consultant: Don Lessem]

[Music Composer: Dave Hummel]

[Editor: Bertrand Morin]

[Science Editor: Eleanor Grant]

[Associate Producer: Steven Zorn]

[Researcher: Lisa Schaumanr]

[Animation: Anim8, Inc.]

[Graphics Director: John Wade]

[Illustrator: R. Joseph Jacobson]

[Production Coordinator: Christine Cipriani]

[Production Manager: Joy Nimmo]

[Assistant Editor: Jennifer Rivers]

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[Production Secretary: Nancy Lowery]

[Canada Unit]

[Production Coordinator: Pierre Paquette]

[Production Secretary: Nathalie Genois]

[Additional Crews]

[Directors: Tom Naughton, Christopher Bryson]

[Directors of Photography: Eric Moynier, David Haycox, Peter Hawkins]

[Camera Assistants: Sasha Sarchielli, Steve Simon, Terry McTaggart, Renzo Pia Anchetta]

[Sound Recordists: Daniel Masse, John Dimonico, John Zecca]

[Voice Over Sound Recording: Earworks Digital Audio, Inc.]

[Sound Editing & Mixing: Earworks Digital Audio, Inc., Alan Harper, Robert Smith]

[Film Laboratory: Commonwealth Films]

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[Produced in Association with: The Academy of Natural Science and Dinamation International Corporation]

[Stills & Motion Pictures: American Museum of Natural History, Archive Films, BBC, Cine-Mundo, Natural History Museum, Leiden, National Geographic Society, Welebit Productions, Inc., Productions Quai 32, Inc.]

[Special Thanks: Bringhamton University, Russell Ciochon, Edward Daeschler, Dinamation International Corp, Dinamation International Society, The Field Museum, Chicago, Sylvie Godlin, Lisa Hache, University of Michigan, Old Dominion University Library, G. Philip Rightmire, Alan Thorne, Gregoire Valcour, Milford Wolpoff]

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[Executive Producer: Tom Naughton]

[For The Learning Channel]

[Production Assistant: Laura Thomson]

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[Senior Writer: Georgann Kane]

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[Produced by New Dominion Pictures for]

[TLC, The Learning Channel. Copyright 1994, Discovery Communications, Inc]