万物简史 第635期:神秘的两足动物(13)
These were the australopithecines, and for the next five million years they would be the world's dominant hominid species. (Austral is from the Latin for southern and has no connection in this context to Australia.) Australopithecines came in several
万物简史 第636期:神秘的两足动物(14)
A human body has 206 bones, but many of these are repeated. If you have the left femur from a specimen, you don't need the right to know its dimensions. Strip out all the redundant bones, and the total you are left with is 120what is called a half sk
万物简史 第637期:神秘的两足动物(15)
The American Museum of Natural History in New York has an absorbing diorama that records the moment of their passing. It depicts life-sized re-creations of a male and a female walking side by side across the ancient African plain. They are hairy and
万物简史 第638期:神秘的两足动物(16)
I asked him if he was troubled about the amount of license that was taken in reconstructing the figures. It's always a problem in making re-creations, he agreed readily enough. You wouldn't believe how much discussion can go into deciding details lik
万物简史 第639期:神秘的两足动物(17)
Matters grew murkier still in 2001 and 2002 when four exceptional new specimens were found. One, discovered by Meave Leakey of the famous fossil-hunting family at Lake Turkana in Kenya and called Kenyanthropus platyops (Kenyan flat-face), is from abo
万物简史 第640期:神秘的两足动物(18)
All this is problematic enough when you are the intellectual master of the planet,but when you are a small, vulnerable australopithecine, with a brain about thesize of an orange, the risk must have been enormous. Absolute brain size doesnot tell you
万物简史 第641期:神秘的两足动物(19)
But stepping out onto theopen savanna also clearly left the early hominids much more exposed. An uprighthominid could see better, but could also be seen better. Even now as a species,we are almost preposterously vulnerable in the wild. Nearly every l
万物简史 第642期:神秘的两足动物(20)
At one point between three and two million years ago, it appears there may have been as many as six hominid types coexisting in Africa. Only one, however, was fated to last: Homo, which emerged from the mists beginning about two million years ago. No
万物简史 第643期:神秘的两足动物(21)
Homo habilis (handy man) was named by Louis Leakey and colleagues in 1964 and was so called because it was the first hominid to use tools, albeit very simple ones. It was a fairly primitive creature, much more chimpanzee than human, but its brain was
万物简史 第644期:神秘的两足动物(22)
Tattersall thinks the rise of a big brain may simply have been an evolutionary accident. He believes with Stephen Jay Gould that if you replayed the tape of lifeeven if you ran it back only a relatively short way to the dawn of hominidsthe chances ar
万物简史 第644期:神秘的两足动物(23)
Luckily for us, one dida group of tool users, which seemed to arise from out of nowhere and overlapped with the shadowy and much disputed Homo habilis. This is Homo erectus, the species discovered by Eugene Dubois in Java in 1891. Depending on which
万物简史 第644期:神秘的两足动物(24)
Although erectus had been known about for almost a century it was known only from scattered fragmentsnot enough to come even close to making one full skeleton. So it wasn't until an extraordinary discovery in Africa in the 1980s that its importanceor
万物简史 第644期:神秘的两足动物(25)
It was also discovered that Homo erectus skulls contained (or, in the view of some, possibly contained) a Broca's area, a region of the frontal lobe of the brain associated with speech. Chimps don't have such a feature. Alan Walker thinks the spinal
万物简史 第644期:神秘的两足动物(26)
There are several more plausible alternative explanations for how Homo erectus managed to turn up in Asia so soon after its first appearance in Africa. First, a lot of plus-or-minusing goes into the dating of early human remains. If the actual age of
万物简史 第644期:神秘的两足动物(27)
What is certain is that sometime well over a million years ago, some new, comparatively modern, upright beings left Africa and boldly spread out across much of the globe. They possibly did so quite rapidly, increasing their range by as much as twenty
