of the last
common ancestor,’ he said. ‘Putting a date on it using the molecular clock assumes a constant mutation rate, which we can’t
be sure about.’
It’s true that different genetic studies have produced different predictions of age of a last common ancestor – but most agree
that the date lies between 100,000 and 200,000 years ago. 11
It was clear that Professor Wu had much more faith in what he considered to be the hard – fossil – evidence, and he was absolutely
sure that the fossils pointed to regional continuity. For him, as for Alan Thorne, Homo erectus and Homo sapiens were not even separate species, but subspecies. Wu preferred the labels Homo sapiens erectus and Homo sapiens sapiens . He argued that one form had gradually changed into the other over time, without speciation, and that the unity of the species
across the world was maintained through gene flow between populations. Wu himself had proposed this theory, of ‘continuity with hybridisation’.
But there does seem to be a significant temporal gap between archaic and modern human fossils in China. The most recent archaic
fossils, from Xujiayo, date to around 100,000–125,000 years ago. The oldest well-dated modern human remains in China, including
a mandible and limb bones, were discovered in Tianyuan Cave, about 6km away from the main site at Zhoukoudian. AMS radiocarbon
dating placed these fossils at 39,000–42,000 years old. 12 The next oldest modern human remains in the Far East are some leg bones from Yamashita-cho, Okinawa, dated to around 32,000
radiocarbon thousand years old (about 37,000 calendar years), and the Upper Cave skulls, at around 10,000 to (at a push) 30,000
years old. And, on balance, it seems that most investigators believe that the gap between archaic and modern Chinese fossils
is not only temporal, but also morphological and genetic. Having seen the fossils and casts of Peking Man, I was not at all
convinced that I had seen the ancestors of the Chinese.
But there was something else in China that Wu believed supported his theory of regional continuity: stone tools. And here,
I had to admit, he had a point. In Europe, the arrival of modern humans on the scene was marked by a clearly new ‘archaeological
signature’, a sudden change in stone tool technology, with the appearance of the Upper Palaeolithic.
In the East, modern humans seem to have been around for a long time before a distinct toolkit appears.
An Archaeological Puzzle: Zhujiatun, China
From around 1,000,000 to 30,000 years ago, the stone tools of East Asia are predominantly fairly crude, Oldowan-style pebble
and flake tools. The archaeology of this part of the world is particularly strange, when viewed from a European perspective. The Acheulean,
with its classic hand axes, doesn’t really happen, and neither does the Middle Palaeolithic. 1 , 2 People just seem to carry on using really basic pebble tools that even Neanderthals would have considered crude. In 1955,
this moved American archaeologist Hallam Movius deprecatingly to call the East ‘a marginal area of cultural retardation’. 3
It’s not until 30,000 years ago, in the late Upper Pleistocene, that the Upper Palaeolithic appears in China, with more sophisticated
tools like end-scrapers, burins, blades and microblades, as well as tools made from bone and antler. But that transition happened
some 20,000 to 30,000 years after genetic estimates for the arrival of modern humans in East Asia, and a good 10,000 years
after the first fossil evidence of modern humans in China. 4 Before then, the tools the modern humans were making were no different from the tools made by earlier archaic humans in the
East. It was this persistence of pebble tools – the so-called ‘chopper-chopping’ technology – that Wu interpreted as archaeological
evidence for regional continuity. If all we had to look at were the stone tools, then regional continuity does seem
Katherine Losse
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Bruce Feiler
Unknown
Olivia Gates