英语听力：探索发现 科学新发现：我们的大气层-10

 Evidence of the first oxygen in the atmosphere. The gas was released by a humble¹ microscopic² living organism called cyanobacteria. Well it turns out cyanobacteria are the only things that can actually produce oxygen, so we know that at some point cyanobacteria colonized³ enough of the planet in order to produce enough oxygen that it became resident in the atmosphere. 

 

As the microbes multiplied and spread, the gas built up in the air, transforming the planet in a process known as the Great Oxidation Event. 

 

Oxygen is very powerful. The world got turned upside-down. Everything has to begin to adapt to now a completely new atmosphere where oxygen is dominating.

 

First the oxygen reacted with the oceans, causing iron within them to form rusty⁴ deposits on the seafloor. Then its effects reached dry land. It reacted with soil and rock, giving them a reddish, rusty tinge⁵. And once these minerals had absorbed their fill of oxygen, the gas began to gather in the atmosphere with dramatic consequences for life. 

 

Complex animals could have much higher metabolisms⁶ because of the sheer potential that oxygen provided for them, a whole different kind of evolution was able to take place. Powered by oxygen, life evolved from single-celled organisms to complex animals.

1 humble   

adj.谦卑的，恭顺的；地位低下的；v.降低，贬低

参考例句：

• In my humble opinion,he will win the election.依我拙见，他将在选举中获胜。
• Defeat and failure make people humble.挫折与失败会使人谦卑。

2 microscopic   

adj.微小的，细微的，极小的，显微的

参考例句：

• It's impossible to read his microscopic handwriting.不可能看清他那极小的书写字迹。
• A plant's lungs are the microscopic pores in its leaves.植物的肺就是其叶片上微细的气孔。

3 colonized   

开拓殖民地，移民于殖民地( colonize的过去式和过去分词 )

参考例句：

• The area was colonized by the Vikings. 这一地区曾沦为维京人的殖民地。
• The British and French colonized the Americas. 英国人和法国人共同在美洲建立殖民地。

4 rusty   

adj.生锈的；锈色的；荒废了的

参考例句：

• The lock on the door is rusty and won't open.门上的锁锈住了。
• I haven't practiced my French for months and it's getting rusty.几个月不用，我的法语又荒疏了。

5 tinge   

vt.(较淡)着色于，染色；使带有…气息；n.淡淡色彩，些微的气息

参考例句：

• The maple leaves are tinge with autumn red.枫叶染上了秋天的红色。
• There was a tinge of sadness in her voice.她声音中流露出一丝忧伤。

6 metabolisms   

n.新陈代谢( metabolism的名词复数 )

参考例句：

• Garden snails are evolving slower metabolisms. 花园蜗牛新陈代谢进化缓慢。 来自互联网
• Elite swimmers tend to be born with certain advantages, such as superefficient metabolisms. 精华的游泳者趋于与某个优点出生，例如superefficient新陈代谢。 来自互联网