万物简史 第644期:永不安分的类人猿(5)（在线收听）

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.

解释人类迁移的传统理论——现在仍为该领域内大多数人所接受的那种理论——认为人类迁移至欧亚大陆出现过两次浪潮。第一次是直立人，他们以不可思议的速度走出非洲——几乎是他们一成为人种就已开始了——这次迁移开始于大约200万年前。他们在不同地区定居下来，这些早期的直立人后来进化成一些有自己特色的人科动物——在亚洲成了爪哇人和北京人；在欧洲先是进化成海德堡人，最后是尼安德特人。

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."

接着，大约在10万多年前，一个更为灵巧的种属——我们现在活着的每个人的祖先——出现在非洲平原上，并且开始向外迁移，出现了第二次浪潮。根据这一理论，在他们所到之处，这些新的智人取代了他们较为愚钝、不大灵活的祖先。但是他们究竟是怎样做到这一点的，学术界一直争论不休。没有任何屠杀的迹象，因此大多数专家认为，后来者是在竞争中淘汰了先到者，尽管其他因素也可能起了作用。“也许我们让他们感染了天花，”塔特萨尔说，“真的说不准。有一点可以肯定的是，现在我们在这里，而他们不在了。”