托福阅读模拟练习之人类起源.pdfVIP

智 课 网 托 福 备 考 资 料 托福阅读模拟练习之人类起源 托福阅读的关键是在于多看多练，为了帮助广大考生更好的复习， 小编为大家整理提供托福阅读模拟练习，以供各位考生复习参考，生活 中有很多事情需要大家细心观察和发现，阅读文章不仅可以锻炼能力还 能了解各方面的知识。在托福阅读练习中大家要多找些托福文章练习， 小编也会经常找些文章让大家参考的，下面开始今天的托福阅读吧。 There are two main hypotheses when it comes to explaining the emergence of modern humans. The ‘Out of Africa’ theory holds that homo sapiens burst onto the scene as a new species around 150,000 to 200,000 years ago in Africa and subsequently replaced archaic humans such as the Neandertals. The other model, known as multi-regional evolution or regional continuity, posits far more ancient and diverse roots for our kind. Proponents of this view believe that homo sapiens arose in Africa some 2 million years ago and evolved as a single species spread across the Old World, with populations in different regions linked through genetic and cultural exchange. Of these two models, Out of Africa, which was originally developed based on fossil evidence, and supported by much genetic research, has been favored by the majority of evolution scholars. The vast majority of these genetic studies have focused on DNA from living populations, and although some small progress has been made in recovering DNA from Neandertal that appears to support multi-regionalism, the chance of recovering nuclear DNA from early human fossils is quite slim at present. Fossils thus remain very much a part of the human origins debate. Another means of gathering theoretical evidence is through bones. Examinations of early modern human skulls from Central Europe and Australia dated to between 20,000 and 30,000 years old have suggested that both groups apparently exhibit traits seen in their Middle Eastern and African predecessors. But the early modern specimens from Central Europe also display Neandertal traits, and the early modern Australians showed affinities to archaic Homo from Indonesia. Meanwhile, the debate among paleoanthropologists continues , as supporters of the two hypotheses ch