与摩根·弗里曼一起穿越虫洞（2010）

Through The Wormhole With Morgan Freeman S05E05

Part 2 April 19, 2021, 3:02 p.m.

就像是探究最早的自行车是如何工作的
is like figuring out how the very first bicycle worked.
自行车是不断变化的
Bikes are permanently changing.
每十年都有新的发展
Every 10 years, we have new developments,
会加上新的结构和新的电子设备
new mechanisms, new electronics added to them.
但是自行车的基本结构是相对固定的
In contrast, the structure of a bike is rather permanent.
现代自行车有着非常精密的传动装置
Bikes today come with a variety of sophisticated gears
以及高科技材料
and high tech materials,
但仍有着共同的基本结构
but all share common, essential structures.
没有它们，自行车就不能运行
Without them, a bike cannot function.
在第一辆自行车上，我能够找到车座、
In the first bike, I would find a seat,
踏板、车轮
pedals, wheels,
因为这些东西在我现在研究的自行车上
because these seem to be common to all bikes
仍然存在
that I can study today.
对于这些基本部件的研究
With a list of these fundamental parts,
古斯塔沃重建出了自行车的
Gustavo can reconstruct the last universal common ancestor
共同祖先
of bicycles --
古董自行车
the penny-farthing...
第一个被称作自行车的设备
...the first machine to be called a bicycle.
它有车座、脚踏板和车轮
It had a seat, pedals, and wheels,
但不需要链条或齿轮等传动装置
but didn't need a chain or gears to move.
古斯塔沃将这一原理应用于对卢卡的研究中
Gustavo applied this same philosophy to his hunt for LUCA.
通过将上千种生物的基因结构
By comparing the fossil records
与化石记录进行比较
to the genetic record of thousands of organisms,
古斯塔沃得知了哪些蛋白质存在于
Gustavo worked out which proteins existed
35亿年前
about 3.5 billion years ago.
他列出了卢卡所需的
He generated a list of fundamental parts
所有基本部件
that LUCA must have had.
让他惊讶的是，他发现
To his surprise, he discovered
卢卡和当今的生物非常不同
that unlike all life we know of today,
卢卡很可能不具备密封性良好的细胞壁
LUCA probably did not have a well-sealed cell wall.
很可能
It is quite possible
卢卡的细胞壁是多孔的
that the cell walls of LUCA were porous,
这就允许不同卢卡细胞之间
and that they would allow for fast exchange
进行遗传物质的快速交换
between the different LUCA cells of genetic information,
包括一些细胞结构的交换
and also of actual machinery.
我们把卢卡细胞当做古董自行车
Think of a LUCA cell as a penny-farthing bicycle.
由于其细胞壁布满了孔洞
Because its cell wall was full of holes,
卢卡细胞的重要组成部分可以流动
important parts could come loose and float away.
而水分子则与脱离的部分相互作用
Water molecules could, however, react to this escaped part
在其周围形成保护层
and form a supportive mold around it
直到这部分被另一个卢卡细胞捕获
until it drifts into another LUCA cell
那么这部分就又重新利用了
where that part could be reused.
卢卡细胞之间互相依存
LUCA cells depended on one another
水则保证了整个卢卡群落的生存
and water chemistry to keep the entire colony alive.
古斯塔沃认为
Gustavo believes
卢卡细胞并非独♥立♥的生物体
that rather than being many distinct organisms,
这些细胞的行为像是
these cells behaved like parts
一个巨大的整合生物体的一部分
of a single, giant, cooperative being,
属于一个超个体
a superorganism.
就像多细胞生物
As multi-cellular organisms
由许多单个细胞组成
are made of individual cells,
超个体生物则由许多
a superorganism is composed of many organisms
互相紧密联♥系♥的个体组成
that are interacting heavily with each other.
超个体是由许多个体
A superorganism is a creature
组成的生物，就像一窝蜜蜂
made up of many individuals, like the hive of bees.
如果古斯塔沃是对的
If Gustavo is correct,
地球上的第一个生命
the very first life forms on earth
并不是单个的微小细胞
were not isolated microscopic cells,
而是广袤的海洋本身
but rather the vast ocean itself,
一个覆盖在几乎整个星球表面的超个体生物
a superorganism that covered nearly the entire planet.
我们也许都是
We might all be descendants
这个超大生物的后代
of a single, supermassive creature.
卢卡主宰的时代已经过去几十亿年了
Billions of years have passed since the time of LUCA.
那么海洋现在仍是超个体吗？
Is the ocean still a superorganism?
有一位科学家试图探索
One scientist is trying to find out
海洋作为一个整体是否有食欲
by studying whether the ocean, as a whole, has an appetite.
你怎么知道某个东西是不是活的？
How do you know whether something is alive?
这个问题困扰了人们几个世纪
It is a question great minds have argued over for centuries.
对于哲学家勒奈·笛卡尔来说
To the philosopher Rene Descartes,
答案是：“我思故我在”
the answer was, "I think, therefore I am."
但生物学家有着不同的标准
But biologists have come up with a different criterion,
这也许就能揭示出新的生命形式
one that could reveal a new form of life.
答案也许是：“我吃故我在”
The answer could be, "I eat, therefore I am."
和每个生物学家一样，纽约大学的泰勒·沃尔克认为
New York University's Tyler Volk believes, like every biologist,
所有生命都要能够进行新陈代谢
that all living things have a metabolism.
新陈代谢是一个生物活性反应过程
A metabolism is a biologically active process
能够将特定化学物质
that breaks down certain chemical compounds
降解成小组分
into smaller constituents,
然后将这些小组分重新组合。（图中是ATP生成过程）
and then rearranges those constituents.
地球上你所能想到的所有生物
Every creature you can think of on the planet
都能进行新陈代谢
has a metabolism.
生物体内的各个器官从营养物质中获取能量
Organs inside these creatures extract energy from nutrients,
然后排出残渣
then discard the leftovers.
海洋中到处都是进行新陈代谢的生物
The ocean is filled with life forms that do this.
但海洋本身
But the ocean itself
通常不会被认为是生物
is not usually considered a living being.
反而人们会认为它是个大型循环净化器
Instead, it is thought of as an enormous recycler.
海洋中有一些组分
Some of the elements in the ocean
作为可被利用的成分循环了数百次
are recycled hundreds of times in and out of the useful forms
一次又一次的被海洋中的生命利用
that can be taken back up by life again over and over again.
但当泰勒仔细审视
But when Tyler took a closer look
海洋的循环系统后，他发现物质总量是不会增加的
at the ocean's recycling system, the numbers didn't add up.
海洋生命间营养元素的循环
Life in the ocean recycles essential nutrients
比如碳、磷、氮和硫
like carbon, phosphorous, nitrogen, and sulfur
通过生与死的过程进行
through a process of life and death.
一些生物以其他生物为食
Life feeds on life, which feeds life,
却又是其他生物的食物，生命这样不断重复
which feeds other life, and life is renewed.
这是一个近乎完美的循环系统
It's a near-perfect recycling system.
泰勒准确的追踪了营养物质
Tyler has tracked precisely how efficiently
被重新利用的效率
each of these nutrients gets reused.
他的分♥析♥结果表明
His analysis reveals
海洋中并不是所有支撑生命的元素
that not every life-sustaining element in the ocean
是被100%重复利用的
is 100% recycled.
计算表明
The calculations show
海洋中惊人的生化循环
that as marvelous as these biochemical cycles are
并不是完美的
inside the ocean, they're not perfect.
海洋需要新的营养成分
There is a need for fresh elements,
组成生命的基本化学成分
the chemical elements essential to life.
泰勒认为这种不完美的循环
Tyler argues this imperfect recycling
意味着海洋作为一个巨型生命
means that the ocean, a giant system of life,
也有新陈代谢作用
has a metabolism.
跟我们一样，海洋也要进食
Just like us, the ocean feeds.
我们所谓的河口
So, what we call the mouth of the river,
你可以认为是海洋的嘴
you can think of as the mouth of the ocean.
它们是重要物质
These are the portals
进入海洋的大门
by which very important materials come into the ocean.
接着，把来自河流的物质代谢过后
And, after it metabolizes its food from rivers,
海洋就会产生废物，沉积在海底
it excretes waste into the ocean floor.
海洋中也存在有废弃的副产物
In the ocean, there will be waste byproducts.
有一些特定物质会沉积下来
There will be certain compounds that will go into the sediment,
覆盖起来，不被任何
get covered up, and not get recycled
微生物或小生物所重复利用
by the microbes or by the worms.
泰勒认为即使生命互相为食
Tyler thinks that even though they feed on one another,
但海洋中的生命最终都是在合作
life forms in the ocean are ultimately working together,
就像身体内的各个器官一样
like organs inside a body.
一个包含有鱼类和哺乳动物的群体
One group, which includes fish and mammals,
像人类的呼吸系统一样工作
works like the human respiratory system.
它们吸收氧气和碳源
It takes in oxygen and carbon
将其转变成二氧化碳
and transforms it into carbon dioxide.
另一群体，海洋植物
Another group, ocean plant life,