生命的奇迹（2013）

because to make sense of all that information,
我们必须有能力处理它们
we need to be able to process it.
每只人眼含有
Each one of my eyes contains
超过1亿个感光细胞
over 100 million individual photoreceptor cells.
这大约是一般数码相机的
That's about five or ten times the number
5至10倍
in the average digital camera.
如果人类的视觉系统
So if my visual system works
只是不断地收集一系列静止的图像
by just taking a series of individual still images of the world
并将这些信息输送到大脑
and transmitting all that information to my brain,
那大脑便面临超载的危险
then my brain would be overwhelmed.
这样不现实
It's just not practical,
因此动物不这样做
so that's not what animals do.
相反 它们的视觉系统已进化出
Instead, their visual systems have evolved
只提取必要信息的能力
to extract only the information that is necessary.
福勒蟾蜍
蟾蜍属
蟾蜍就是很好的范例
And this is wonderfully illustrated in the toad.
蟾蜍的眼睛和人眼在结构上十分相似
The toad has eyes that are structurally very similar to ours.
但大多数时候 它们似乎不在工作
But much of the time, it's as if it isn't seeing anything at all.
蟾蜍似乎对周围环境一概不知
It seems completely oblivious to its surroundings.
直到它们感兴趣的东西出现 例如面包虫
Until something, like a mealworm, takes its interest.
蟾蜍的视觉主要用来
If you think about what's important to a toad visually,
感知猎物或天敌
then it's the approach of either pray or predators,
因此它们的视觉逐渐优化以适应这一点
so the toad's visual system is optimised to detect them.
我们将虫子放在蟾蜍面前
So, there, we've put a worm in front of the toad,
看见了吗
and did you see that?
它以惊人的速度吃掉了虫子
Incredibly quickly, the toad ate the worm.
面包虫一出现在蟾蜍面前
As soon as the mealworm wriggles in front of the toad,
它的眼睛就锁定了目标
its eyes lock onto its target.
瞬息之间 它便发动袭击
Then it strikes in a fraction of a second.
这种精确的反应甚是神奇
It's an astonishingly precise reaction,
却也异常简单
but it's also a very simple one.
因为蟾蜍只会关注
Because the toad is only focusing on
面包虫的一个特征
one property of the mealworm -
它移♥动♥的方式
the way it moves.
20世纪70年代的实验表明
These 1970s lab tests
任何细长的东西 像虫子一样运动时
show how a toad will try and eat anything long and thin.
蟾蜍都会试图吃掉它们
But only if it moves on its side, like a worm.
这是因为蟾蜍视网膜内的神经回路
And that's because the toad has neural circuits in its retina
只能感知纵向运动
that only respond to lengthwise motion.
如果目标以竖直方式旋转
If, instead, the target is rotated into an upright position,
蟾蜍则毫无反应
the toad doesn't respond at all.
乍见之下 蟾蜍的视觉系统
At first sight, the visual system of the toad
有些原始 也不甚完美
seems a little bit primitive and imperfect.
如果你把蟾蜍放在装满死虫子的水箱中
It is true that if you put a toad in a tank full of dead worms,
因为虫子不会动 蟾蜍不把它们当作食物
it'll starve to death, because they're not moving,
结果它真的会饿死
so it doesn't recognise them as food.
但蟾蜍不需要
But it doesn't need to see
像人类一样看到世界的诸多细节
the world in all the detail that I see it.
它只需关注运动
What it needs to focus on is movement,
只要能捕捉到运动 它就足以生存下去
because if it can see movement then it can survive,
因为它能避开天敌 捕获食物
because it can avoid predators, and it can eat its prey.
从某种意义上来讲
I suppose, in a sense,
既然有东西像虫子一样运动
if it moves like a worm,
在自然界中 那可能就是虫子
in nature, then it's likely to be a worm.
简化这个纷繁的视觉世界
This ability to simplify the visual world
只留下最关键的信息
into the most relevant bits of information
是每种动物必备的能力
is something that every animal does.
我们每时每刻都在这样做
We do it all the time.
我们的视觉系统也能探测运动
We also have visual systems that detect motion.
还能辨别轮廓和面孔
Others identify edges and faces.
想获得更多信息 需要更强的处理能力
But extracting more information takes more processing power.
这要求更大的大脑
That requires a bigger brain.
为了亲眼见证进化
And to see the results of this evolutionary drive
提升了大脑的处理能力
towards greater processing power,
我来到了大都会佛罗里达的中心
I've come to the heart of Metropolitan Florida.
也许看起来不像 但在这立交桥之下
You know, it may not look like it, but underneath this flyover,
就在那边的浅湾里
just out in the shallow water,
是世界上寻找一种神奇生物
is one of the best places in the world
的最佳场所之一
to find a particularly interesting animal.
最大限度地利用
It's an animal that's evolved
眼睛所提供的信息 是这种动物进化出的能力
to make the most of the information its eyes can provide.
接下来我们要去找几只章鱼
Well, what we're going to do is find some octopus.
不过要想找到 可非易事
And it's, as you say in physics, nontrivial.
因为它们演化出了巧妙的方法
Because they've developed a beautiful way
来伪装自己
of camouflaging themselves.
它们能变色 它们的细胞和皮肤会变色
They change colour. Their cells and their skin change colour
以融入周围环境
to match their surroundings.
当然我们没有这个能力
It's an ability that we don't possess, of course.
这使它们很难被发现
It makes them difficult to find.
普通章鱼
章鱼属
快看 它在那里
There he is, look.
它逃向了那边
He went flying into there,
一只螃蟹和一群鱼逃窜了出来
and a crab and a load of fish are flying out,
看它喷出的墨汁
and look at his ink.
这是一种自卫措施 我不知道它去哪了
A defence mechanism. I don't know where he is.
它就藏在那里面
He's hiding somewhere in there.
看它身上的色彩
Look at those colours!
多么神奇的生物
What a remarkable creature.
章鱼虽然和蛞蝓与蜗牛一样
Although the octopus is a mollusc,
同属软体动物
like slugs and snails,
但从很多方面 它与我们更为相似
in many ways, it seems more similar to us.
人们认为它是最聪明的无脊椎动物
It's believed to be the most intelligent invertebrate.
它看起来像是挥拳示♥威♥
It's like he's holding his fists up.
快看
Look at that.
它的大脑拥有五亿个神经细胞
Its brain contains about 500 million nerve cells,
数量于狗的差不多
about the same as a dog's.
你在做什么
What are you doing?
如果在这颗星球上
You know, if you want an example of
想找一个外星智慧生命
an alien intelligence here on earth..
必然是它
that must surely be it.
它利用大脑掌握了几项神奇的技能
And it's used that brain to develop some remarkable abilities.
它是技艺高超的模仿者
It's become a skilled mimic.
不仅可以迅速改变颜色
It can rapidly change not only its colour,
还有外形 以融入环境
but its shape, to match the background.
有些章鱼甚至可以模仿其他动物
Some species even do impressions of other animals.
孔雀鲆
鲆属
它们是狡猾的猎手
They become cunning predators,
解决问题的老手
and adept problem-solvers.
甚至有报告显示 它们会使用工具
They've even been reported to use tools.
这些技能都表明了高超的智力
All these skills are signs of great intelligence,
但它们也依赖于敏锐的视觉
but they also rely on an acute sense of vision.
看它这打量周围环境的大眼睛
Look at those big eyes surveying the surroundings.
正看着我们
Checking us out.
摄像机眼 和我的一样
Camera eyes, just like mine,
章鱼为了保持现有的生存方式
and they're vitally important for allowing the octopus
它们的眼睛至关重要
to live the lifestyle it does,
和我一样 它们也是依赖于视觉的动物
so a visual animal in the same way that I'm a visual animal.
在所有无脊椎动物中
The octopus is one of the only invertebrates
只有章鱼拥有复杂的摄像机眼
to have complex camera eyes.
正如我们的眼睛
Like our eyes,
它们可以捕捉到世界的细节
they capture detailed images of the world.
它们的大脑进化出
And their brains have evolved
从这些图像中提取大量信息的能力
to be able to extract the most information from those images.
视神经叶 包含主要视觉中枢
视神经叶占据了章鱼大脑的百分之三十
The optic lobes make up about 30% of the octopus' brain.
唯一的另一种
The only other group
也将如此多脑细胞用于视觉处理的生物
that is known to devote so much of its brain to visual processing
就是我们
is our group.
灵长类 最聪明的脊椎动物
The primates - the most intelligent vertebrates.
章鱼如此聪慧 是因为它
I think it's a fascinating thought
需要处理大而复杂的眼睛得到的海量信息
that that intelligence is a result of the need to process