地球的力量 第2集 大气(18)光合作用
最重要的是
they're actually the simplest of life forms,
他们实际上是最简单的生命种类
nothing more than bacteria.
不比细菌的细胞多
When you get up close you can see
当你靠近观察
that it's only the outer part that's alive.
就只有外面这一部分是活着的
It's a layer of bacteria that secretes a thin film of slime
这一层细菌分泌一层薄薄的粘液
which builds up layer upon layer.
一层接一层粘合起来
It might not look like it,
它虽然看起来不怎样
but these are the most successful Life forms on the planet.
不过这些是地球上最成功的生命种类
These stromatolites have been around
叠层石诞生至今
for 3,500 million years.
已经三十五亿年了
That's three-quarters of the age of the planet.
相当于地球四分之三的年纪
And yet when they first evolved almost three billion years ago,
同时它们第一次进化是在超过三十亿年前
these simple life forms began one of the most important transformations
这些简单生命类型开始最重要的变形
the planet has ever seen.
地球目睹了这一切
These stromatolites are special
这些叠层石是特别的
because they did something that was quite extraordinary.
因为它们做了非常特别的事情
As they took in the sunlight and photosynthesised,
它们吸收阳光和进行光合作用
they broke down the chemical bonds in water
分解水的化学键
releasing something that would completely change the planet.
生成一些能彻底改变地球的东西
They released oxygen.
它们生成氧气
