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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    用放射性碳測(cè)定年代的一項(xiàng)最新數(shù)據(jù)顯示，現(xiàn)代人祖先進(jìn)入歐洲并逐漸取代尼安德特人的過程要比傳統(tǒng)理論認(rèn)為的更快。
    據(jù)路透社2月23日?qǐng)?bào)道，來自劍橋大學(xué)的科學(xué)家保羅·米拉斯在最新一期的英國《自然》雜志上指出，用放射性碳測(cè)定年代的一項(xiàng)最新數(shù)據(jù)表明，人類祖先從非洲進(jìn)入歐洲后，僅花費(fèi)了5000年的時(shí)間就取代了歐洲早期居民尼安德特人，而不是傳統(tǒng)的理論所認(rèn)為7000年。
    另外，傳統(tǒng)理論還認(rèn)為，現(xiàn)代人祖先最初于大約4.5萬年前在歐洲東部地區(qū)出現(xiàn)，隨后在4.3萬年至3.6萬年以前逐漸向東南歐地區(qū)遷移。但是用放射性碳測(cè)定年代的一項(xiàng)最新數(shù)據(jù)表明，遷移過程應(yīng)該在4.6萬年至4.1萬年前就已經(jīng)發(fā)生了，即現(xiàn)代人祖先更早且更快地進(jìn)入了歐洲。
    米拉斯說，“這個(gè)結(jié)論顯然說明，面對(duì)人類祖先的入侵，當(dāng)時(shí)居住在歐洲的尼安德特人消亡的時(shí)間要更早。”他指出，現(xiàn)代人祖先取代尼安德特人的成動(dòng)主要得利于當(dāng)時(shí)氣候發(fā)生的變化，因?yàn)樗麄儽冗h(yuǎn)古的尼安德特人更能應(yīng)對(duì)惡劣的氣候。他說，“越來越多的跡象表明，歐洲許多地區(qū)的尼安德特人的消亡大都與突如其來的寒冷和干燥氣候環(huán)境有關(guān)聯(lián)。這對(duì)于與人類祖先爭奪歐洲的尼安德特人是致命的一擊?！?BR>    1856年，幾名礦工在德國尼安德特河谷的一個(gè)山洞中發(fā)現(xiàn)了一些頭骨和肢骨化石。最初，這些骸骨化石被描述為一個(gè)“殘忍”的部落或一些因疾病而變得丑陋的人。3年后，英國科學(xué)家達(dá)爾文發(fā)表了其的《物種起源》，隨著達(dá)爾文進(jìn)化論思想的影響越來越大，這些骸骨化石成為史前人種存在的證據(jù)，科學(xué)家把尼安德特人描述為人類進(jìn)化歷程中的一環(huán)。
    尼安德特人是現(xiàn)代人的祖先還是已經(jīng)滅絕的人類旁支？這個(gè)問題已經(jīng)爭論了好多年。若尼安德特人是現(xiàn)代人的祖先，那意味著尼安德特人與晚期智人（現(xiàn)代人的祖先）——克羅馬農(nóng)人通婚過。由于尼安德特人與克羅馬農(nóng)人在歐洲共存了幾千年，他們有充裕的時(shí)間通婚。但在最新的一項(xiàng)研究中，科學(xué)家利用我們已知的克羅馬農(nóng)人與尼安德特人的人口密度空間分布針對(duì)這一問題進(jìn)行了模擬研究。研究表明，克羅馬農(nóng)人與尼安德特人從未“通婚”。德國慕尼黑和美國賓西法尼亞的兩個(gè)科學(xué)小組也聲稱，根據(jù)從尼人骨架上所取得的DNA分析，其結(jié)果支持尼人是4萬年前滅絕的人類旁支的假說。