生命的奇迹（2013）

像雨点一般洒落在地球表面
raining down on the surface of the earth.
蓝色光子能量最高
The blue ones are the highest-energy photons,
红色光子能量最低
the red ones are the lowest-energy photons
所有五彩斑斓的光子
and all the colours of the rainbow in the middle
不过是因为它们携带的能量不同
are just simply photons of different energies.
谢谢
Oh, thank you.
拿这碗红辣椒酱来说
So for this, the chilli salsa which I see as red,
里面含有色素分子
then there are pigment molecules in there
这些分子在吸收来自太阳的
that are absorbing the blue photons,
蓝色光子
the blue light from the sun.
它们不与红色光子相互作用
The red ones, it doesn't interact with,
红色光子被反射进人眼 所以它呈红色
so they bounce back into my eye, and that is why I see it as red.
青椒酱也同理
Same with the green chilli,
但此时 红色光子在参与相互作用
but in this case the red photons are interacting,
发生反应
they're doing something,
想象一下它们在跟色素分子聊天
they're talking to pigments in here,
而绿色光子
and what I am seeing are the green photons
和一些蓝色光子混合起来
and some of the blue photons coming into my eye,
同时反射进人眼 所以它呈青色
mixing up, allowing me to see that as green.
色素给世界带来色彩
Pigments bring colour to the world.
生命经历数十亿年的演化
A planet painted by genes,
基因携带的色彩 装点了地球
honed by billions of years of evolution.
有的色彩警示危险的到来
Some colours warn of danger...
这东西肯定辣死了
This stuff is on fire, I can tell you!
有的用来吸引授粉者
Or attract pollinators.
生命演化出许多利用紫外线的方法
Pigments are one of the ways that life has evolved
其中之一需要用到色素分子
to take on the sun's powerful ultraviolet light.
这小家伙名叫投弹手甲虫
This little guy is called a bombardier beetle.
现在我把它夹起来
If I just grab him...
它的名字源于一种独特的防御方式
His name comes from his unique defence mechanism.
它体内能产生两种化学物质
He produces two chemicals.
一种是大家所熟悉的过氧化氢酶
One of them you might have heard of - hydrogen peroxide.
另一种物质叫做对苯二酚
And the other one is something called hydroquinone,
当它受到惊吓
and when you scare him,
两种化学物质会被同时注入体内某个腔体
both those chemicals are injected into a little chamber in his body.
使其温度升至沸点
Which raises the temperature to the boiling point of water,
随后体内压强增大
and increases the pressure,
最终其尾部会喷射出炽热剧毒的化学物质
squirting a hot and noxious chemical out of its rear.
非常巧妙的防御方式
A clever way to defend yourself.
但这只是投弹手甲虫利用化学物质
But this is just one of the ways this character uses chemistry
增加生存几率的方法之一
to increase its chances of survival.
此刻 无论是投弹手甲虫还是我
Now the bombardier beetle and me,
还是墨西哥高原上所有可见的生物
and in fact every living thing you can see,
都暴露于同样的威胁当中
are exposed to the same threat here, on the high plains of Mexico,
来自太阳的高能紫外线辐射
it's the high-energy ultraviolet photons
不断灼烧着这片土地
raining down on this landscape from the sun.
紫外线一接触皮肤中的DNA 就会破坏它
If they hit DNA in my skin, for example, then they'll damage the DNA.
因此我们需要防御措施
So that's got to be prevented.
我和我的甲虫朋友
Me and my friend, the beetle,
选择了同样的方法
have both reached the same solution -
可以看到这只甲虫表面呈棕黑色
you see that the beetle is brown and black.
而我的皮肤 也在阳光曝晒下渐渐变黑
My skin, when it is exposed to the sun, is going brown.
人体和甲虫体内都会产生黑色素
I am producing a pigment called melanin, and so is the beetle.
黑色素的分子结构非常简单
Now melanin is a very simple molecule,
一圈碳原子 链上了少许其他分子
it's just a ring of carbon atoms with a few extra bits bolted on,
但其中的电子却以十分特殊的方式运动
but its sea of electrons behaves in a very specific way.
当来自太阳的高能紫外线光子
See, when a high-energy ultraviolet photon from the sun
接触到这些电子时
hits one of those electrons,
能量以极快的速度被消耗
it very very quickly dissipates that energy.
具有潜在威胁的光子被吸收
That potentially threatening photon has been absorbed
其所有能量均被消耗 并转换成热量
and all its energy has been dissipated away as heat.
黑色素作用巨大
Melanin is so efficient,
能吸收超过99.9%的有害紫外线辐射
that over 99.9% of the harmful ultraviolet radiation is absorbed.
所以是黑色素
So melanin is protecting
让我的皮肤和投弹手甲虫
both my skin and my friend, the bombardier beetle,
得以免受来自太阳的潜在伤害
from the potentially harmful effects of the sun.
自诞生伊始 所有物种都必须
From the start, life had to evolve strategies
进化出应付年轻烈日的方法
for coping with the energetic young sun.
若不慧黠 生命无以存在
Now life is nothing if not resourceful.
体表色素是生物
Pigments are the way that living things interact
应对太阳辐射的方法
with the radiation from the sun.
为什么只用色素消散能量 保护自我
So why just use them to dissipate energy, to protect?
为什么不借机将此能量化为己用
Why not use them to harness that energy for its own ends?
这正是生物所做的
Well that's exactly what life did.
正因如此 通过引入一种新的物质
And in doing so, it transformed our planet
地球被彻底改变了
by introducing a wonderful new ingredient.
地球上的大气
Earth has an atmosphere
与宇宙中已知其他行星的都不同
unlike any other planet we know of in the universe.
只有在地球上的空气中能点燃火焰
Only in the air on our world do fires burn.
只有地球上充满了
Only on our world has a gas been released
能让高等生物延续生命的气体
which allowed complex life to evolve.
让我们的母星如此特殊的原因
What makes our home unique
正是其含氧丰富的大气层
is its oxygen-rich atmosphere.
在塔巴斯科群山中的一处洞穴 你能够
Deep in a cave in the hills of Tabasco, you can find a hint
大致了解一个缺氧行星的模样
of what a living planet without oxygen might be like.
这是我们星球上最独特的环境之一
This is one of the more unique environments on our planet.
洞穴中遍布着硫 从水中就可以看出
This cave is full of sulphur, you can see it in the water.
流经洞穴的湖水
You can see that milky colour of the lake
是奶白色的
that's flowing through the cave.
这是硫溶于水造成的
That is dissolved sulphur.
而硫来自于硫化氢气体
And it's coming from hydrogen-sulphide gas,
该气体的来源至今仍无定论
the source of which is actually not entirely known.
硫化氢是有毒气体
The hydrogen sulphide is toxic to me.
并对这地狱般的地方造成惊人的影响
And it has another rather alarming effect on this hellhole.
这种气体不仅气味难闻
It is a bad-smelling gas,
它还将氧气挤出洞穴
but it is also a gas that drives the oxygen out,
所以越到洞穴深处 氧气越少
so as you go on into the cave system, you get less and less oxygen.
在某种意义上 在这洞穴的深处
In a sense, some of the chemistry,
发生的化学或生化反应
the biochemistry that takes place in the dark of this cave system,
都与地球诞生之初的
could be very similar to the chemistry
化学和生化反应类似
and biochemistry that occurred when our planet was very young.
在地球形成的前半段时期
For the first half of its history,
大气中没有氧气
Earth was without oxygen in its atmosphere.
难以置信的是 虽然我只能
But incredibly, in this echo of the past,
在这个地球初期的缩影中待上几分钟
which I can only visit for a few minutes,
有些生命却能在这里安家落户
there are forms of life that are completely at home.
看那里
Look at that!
就在那 以硫化物为生的菌类
There they are, cities of sulphur-eating bacteria
它们以硫化氢气体为生
living off the hydrogen-sulphide gas.
极端微生物群落
Colonies of extremophiles,
赖以生存的气体
organisms that are living off a very different environment of gases
与地表生物截然不同
to the one that we are used to on the surface.
它们展现了过去生物的生活方式
They are a window on a much earlier time.
因为如果没有氧气
Because without oxygen,
我们的母星将只能孕育
the ancestors of these extremophiles
这些极端微生物的祖先
were the only forms of life our planet could support.
了解地球上如何出形成
Understanding how Earth developed
富含氧气的大气经历了几个世纪
an atmosphere rich in oxygen has taken centuries.
其奥秘在于一种古老的菌类
And the secret lies with ancient bacteria.
1676年 一个叫安东尼奥·列文虎克的荷兰人
In 1676, a Dutchman called Antonie Leeuwenhoek
正在研究胡椒为何有辣味
was trying to find out why pepper is spicy.
起初 他认为是胡椒子上有细小的刺
See, they thought that there were little spikes on peppercorns
能刺♥激♥人的舌头
that dug into your tongue.
他使用了五六十年前
He was using the microscope,
就已经问世的显微镜
which had been discovered about 50 or 60 years before,
可是不知为何
what inexplicably,
显微镜之前一直没有派上用场
had never been used for anything useful before.
他将胡椒子放上显微镜
And he put the peppercorns on there
并观察 可是什么也看不见
and looked down and he couldn't see anything,
于是他想 "好吧 让我把它们磨碎"
so he thought "O.K, I'll would grind them up,"