新托福考试阅读练习资料:The Most Successful Species on Earth

所属专题:托福学习资料  来源:互联网    要点:托福阅读  
编辑点评: 大家一定已经看了非常多关于托福阅读的考试复习方法、应试技巧等内容,这里就为大家例举一些典型的托福阅读材料,大家来测测自己目前的水平如何?平时的积累和复习有没有达到目的?!

下文是关于“在我们人类已知的物种中,哪种生物最成功”的研究,我们就来详细看一看吧。 

For many scientists, a species’ success is measured by sheer numbers. In that case, the most successful species known to man is a type of bacterium known as S-A-R-11, or SAR-11 for short. Scientists estimate that there are two-hundred and forty times a billion billion billion SAR11 cells floating around in the oceans. Now that makes six-billion humans sound like a mere handful.

SAR11 bacteria are known for their ability to transform one substance into another, which is why they are such an important part of the Earth’s chemical cycles. Although scientists are still uncertain about SAR11′s specific role, it appears to produce carbon dioxide using the oxygen and carbon from organic matter that’s derived from photosynthesis. Scientists speculate that SAR11 plays a major role in the way the ocean’s surface acts as a giant carbon pump that removes carbon dioxide from the atmosphere.

The catch is that SAR11 is what is known as an uncultured organism, which means that scientists haven’t been able to cultivate it under laboratory conditions. This requires scientists to develop pretty indirect genetic methods just to be able to study SAR11 cultures. Now that this technology is available, scientists are sequencing the SAR11 genome in order to figure out exactly what kinds of carbon it uses, and why it’s so successful at ocean living.

>>点击查看托福学习资料专题,阅读更多相关文章!

最新2022托福阅读信息由沪江留学网提供。

请输入错误的描述和修改建议,建议采纳后可获得50沪元。

错误的描述:

修改的建议: