摘要：
用放射性碳测定年代的一项最新数据显示，现代人祖先进入欧洲并逐渐取代尼安德特人的过程要比传统理论认为的更快。
The ancestors of modern man moved into and across Europe, ousting the Neanderthals, faster than previously thought, a new analysis of radiocarbon data shows.

用放射性碳测定年代的一项最新数据显示，现代人祖先进入欧洲并逐渐取代尼安德特人的过程要比传统理论认为的更快。

据路透社2月23日报道，来自剑桥大学的科学家保罗·米拉斯在最新一期的英国《自然》杂志上指出，用放射性碳测定年代的一项最新数据表明，人类祖先从非洲进入欧洲后，仅花费了5000年的时间就取代了欧洲早期居民尼安德特人，而不是传统的理论所认为7000年。

另外，传统理论还认为，现代人祖先最初于大约4.5万年前在欧洲东部地区出现，随后在4.3万年至3.6万年以前逐渐向东南欧地区迁移。但是用放射性碳测定年代的一项最新数据表明，迁移过程应该在4.6万年至4.1万年前就已经发生了，即现代人祖先更早且更快地进入了欧洲。

米拉斯说，"这个结论显然说明，面对人类祖先的入侵，当时居住在欧洲的尼安德特人消亡的时间要更早。"他指出，现代人祖先取代尼安德特人的成动主要得利于当时气候发生的变化，因为他们比远古的尼安德特人更能应对恶劣的气候。他说，"越来越多的迹象表明，欧洲许多地区的尼安德特人的消亡大都与突如其来的寒冷和干燥气候环境有关联。这对于与人类祖先争夺欧洲的尼安德特人是致命的一击。"

1856年，几名矿工在德国尼安德特河谷的一个山洞中发现了一些头骨和肢骨化石。最初，这些骸骨化石被描述为一个"残忍"的部落或一些因疾病而变得丑陋的人。3年后，英国科学家达尔文发表了其著名的《物种起源》，随着达尔文进化论思想的影响越来越大，这些骸骨化石成为史前人种存在的证据，科学家把尼安德特人描述为人类进化历程中的一环。

尼安德特人是现代人的祖先还是已经灭绝的人类旁支？这个问题已经争论了好多年。若尼安德特人是现代人的祖先，那意味着尼安德特人与晚期智人（现代人的祖先）--克罗马农人通婚过。由于尼安德特人与克罗马农人在欧洲共存了几千年，他们有充裕的时间通婚。但在最新的一项研究中，科学家利用我们已知的克罗马农人与尼安德特人的人口密度空间分布针对这一问题进行了模拟研究。研究表明，克罗马农人与尼安德特人从未"通婚"。德国慕尼黑和美国宾西法尼亚的两个科学小组也声称，根据从尼人骨架上所取得的DNA分析，其结果支持尼人是4万年前灭绝的人类旁支的假说。

（国际在线独家资讯 蒋黎黎）

The ancestors of modern man moved into and across Europe, ousting the Neanderthals, faster than previously thought, a new analysis of radiocarbon data shows.

Rather than taking some 7,000 years to colonize Europe from Africa, the reinterpreted data shows the process may only have taken 5,000 years, scientist Paul Mellars from Cambridge University said in the science journal Nature on Wednesday.

"The same chronological pattern points to a substantially shorter period of chronological and demographic overlap between the earliest ... modern humans and the last survivors of the preceding Neanderthal populations," he wrote.

The reassessment is based on advances in eliminating modern carbon contamination from ancient bone fragments and recalibration of fluctuations in the pattern of the earth's original carbon 14 content.

Populations of anatomically and behaviourally modern humans first appeared in the near eastern region some 45,000 years ago and slowly expanded into southeastern Europe.

Previously it was thought that this spread took place between 43,000 and 36,000 years ago, but the re-evaluated data suggests that it actually happened between 46,000 and 41,000 years ago -- starting earlier and moving faster.

"Evidently the native Neanderthal populations of Europe succumbed much more rapidly to competition from the expanding biologically and behaviourally modern populations than previous estimates have generally assumed," Mellars wrote.

He said the invasion could have been helped by a major change in the climate which modern man would have been technologically and culturally better equipped to deal with than the more primitive Neanderthals.

"There are increasing indications that over many areas of Europe, the final demise of the Neanderthal populations may have coincided with the sudden onset of very much colder and drier climatic conditions," Mellars wrote.

"This could have delivered the coup de grace to the Neanderthals in many parts of western and central Europe in their economic and demographic competition with the incoming modern groups," he added.

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