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Science:人类像入侵物种一样在南美繁衍

摘要 : 人类用了很长的时间才到达南美洲。但是,他们一到那里就像野草一样繁衍开来——实际情况和这个比喻几乎是一样的。

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人类用了很长的时间才到达南美洲。但是,他们一到那里就像野草一样繁衍开来——实际情况和这个比喻几乎是一样的。在一项新研究中,研究人员记录总结了1147个已被放射性碳测定为距今14000年前(正好在南美已知最早的定居点的年代左右)和距今2000多年前之间的考古遗址。通过在地图上标注出这些遗址,科学家们可以看到人们生活的地点和时间。13,000年前至9000年前这段时间里,定居点的密度迅速并稳步地增加,同时人类繁衍到这片无人居住的大陆的每一个角落,并开始学会利用它的资源。(相较他们的祖先被困在白令苔原6000年,这真是好太多了。)但大约9000年以前,南美人口增长似乎开始趋于平稳,研究人员今天在《自然》杂志上报告说。很多入侵物种都采取这个模式:它们发现自己处于一个新的、适宜的栖息地后便迅速蔓延,但随后用尽资源,增速放缓趋稳。然而,南美洲的人们最终发现了绕过这个自然极限的方法。大约5000年前,人口开始再次扩张,这次他们增长得更快。那么是什么发生了改变呢?南美各地的人们从狩猎采集转变到农耕。农业和久坐的生活方式给了他们更多的时间和资源,让大量生育变得更加容易。

原文链接:

Humans spread through South America like an invasive species

原文摘要:

It took humans a long time to reach South America. But once they got there, they spread like weeds—literally. In a new study, researchers tallied up 1147 archaeological sites that had been radiocarbon-dated to between 14,000 years ago (right around the earliest known settlements in South America) and 2000 years ago. By mapping those sites, the scientists can see wher people lived and when. The density of settlements increased rapidly and steadily from 13,000 to 9000 years ago, as humans spread to every corner of the unoccupied continent and learned to take advantage of its resources. (Way better than the 6000 years their ancestors spent stranded in the Beringian tundra.) But about 9000 years ago, South American population growth appears to level off, the researchers report online today in Nature. That’s a pattern followed by many an invasive species that finds itself in a new, hospitable habitat: It spreads quickly but then maxes out its resources and levels off. Eventually, however, people in South America found a way around this natural limit. about 5000 years ago, human populations started expanding once again, at this time, they grew even more rapidly. So what changed? People all over South America transitioned from hunting and gathering to farming. Agriculture and sedentary lifestyles gave them more time and resources, making it easier to have lots of babies.

来源: Science 浏览次数:0

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