A short history of nearly everything - Bill Bryson [229]
The problem, as ever, is the fossil record. “Very few parts of the world are even vaguely amenable to the long-term preservation of human remains,” says Thorne, a sharp-eyed man with a white goatee and an intent but friendly manner. “If it weren't for a few productive areas like Hadar and Olduvai in east Africa we'd know frighteningly little. And when you look elsewhere, often we do know frighteningly little. The whole of India has yielded just one ancient human fossil, from about 300,000 years ago. Between Iraq and Vietnam—that's a distance of some 5,000 kilometers—there have been just two: the one in India and a Neandertal in Uzbekistan.” He grinned. “That's not a whole hell of a lot to work with. You're left with the position that you've got a few productive areas for human fossils, like the Great Rift Valley in Africa and Mungo here in Australia, and very little in between. It's not surprising that paleontologists have trouble connecting the dots.”
The traditional theory to explain human movements—and the one still accepted by the majority of people in the field—is that humans dispersed across Eurasia in two waves. The first wave consisted of Homo erectus, who left Africa remarkably quickly—almost as soon as they emerged as a species—beginning nearly two million years ago. Over time, as they settled in different regions, these early erects further evolved into distinctive types—into Java Man and Peking Man in Asia, and Homo heidelbergensis and finally Homo neanderthalensis in Europe.
Then, something over a hundred thousand years ago, a smarter, lither species of creature—the ancestors of every one of us alive today—arose on the African plains and began radiating outward in a second wave. Wherever they went, according to this theory, these new Homo sapiens displaced their duller, less adept predecessors. Quite how they did this has always been a matter of disputation. No signs of slaughter have ever been found, so most authorities believe the newer hominids simply outcompeted the older ones, though other factors may also have contributed. “Perhaps we gave them smallpox,” suggests Tattersall. “There's no real way of telling. The one certainty is that we are here now and they aren't.”
These first modern humans are surprisingly shadowy. We know less about ourselves, curiously enough, than about almost any other line of hominids. It is odd indeed, as Tattersall notes, “that the most recent major event in human evolution—the emergence of our own species—is perhaps the most obscure of all.” Nobody can even quite agree where truly modern humans first appear in the fossil record. Many books place their debut at about 120,000 years ago in the form of remains found at the Klasies River Mouth in South Africa, but not everyone accepts that these were fully modern people. Tattersall and Schwartz maintain that “whether any or all of them actually represent our species still awaits definitive clarification.”
The first undisputed appearance of Homo sapiens is in the eastern Mediterranean, around modern-day Israel, where they begin to show up about 100,000 years ago—but even there they are described (by Trinkaus and Shipman) as “odd, difficult-to-classify and poorly known.” Neandertals were already well established in the region and had a type of tool kit known as Mousterian, which the modern humans evidently found worthy enough to borrow. No Neandertal remains have ever been found in north Africa, but their tool kits turn up all over the place. Somebody must have taken them there: modern humans are the only candidate. It is also known that Neandertals and modern humans coexisted in some fashion for tens of thousands of years in the Middle East. “We don't know if they time-shared the same space or actually lived side by side,” Tattersall says, but the moderns continued happily to use Neandertal tools—hardly convincing evidence of overwhelming superiority. No less curiously, Acheulean tools are found in the Middle East well over a million years ago, but scarcely exist in Europe until just 300,000