未登录,请登录后再发表信息
最新评论 (0)
播放视频

黑暗中动物是怎么能看见的?

How do animals see in the dark? - Anna Stöckl

在人类眼中 夜晚的世界是无序杂乱的灰色
To human eyes, the world at night is a formless canvas of grey.
而对于夜间动物而言
Many nocturnal animals, on the other hand,
它们眼中的世界更为精彩:充满各类细节、形状、
experience a rich and varied world bursting with details, shapes, and colors.
颜色蛾子与人类的眼睛到底有何不同?
What is it, then, that separates moths from men?
蛾子与其他的夜间动物能夜间视物
Moths and many other nocturnal animals see at night
因为它们的眼睛可以自动调节适应缺少光线的情况
because their eyes are adapted to compensate for the lack of light.
所有动物的眼睛 无论是不是夜间动物
All eyes, whether nocturnal or not,
都是依靠视网膜上的光感器来捕捉
depend on photoreceptors in the retina to detect light particles,
光线粒子也就是光子然后
known as photons.
光感器向大脑和视网膜内
Photoreceptors then report information about these photons to other cells
其他细胞报告光子的信息
in the retina and brain.
大脑通过筛选信息来建立
The brain sifts through that information and uses it to build up an image
眼睛所看到的周围环境的图像
of the environment the eye perceives.
光线越强 越多光子进入眼睛
The brighter the light is, the more photons hit the eye.
阳光明媚的天气
On a sunny day,
你的眼睛接收的光子比多云阴暗的夜晚
upwards of 100 million times more photons are available to the eye
多一亿倍
than on a cloudy, moonless night.
在黑暗中光子并不会减少数量
Photons aren’t just less numerous in darkness,
但它们进入眼球的方式更不稳定
but they also hit the eye in a less reliable way.
这意味着光感器收集的信息会
This means the information that photoreceptors collect
随着时间的流逝而改变
will vary over time,
图片的质量也会下降
as will the quality of the image.
黑暗中想要捕捉到随机分散又稀少的光子
In darkness, trying to detect the sparse scattering of randomly arriving photons
对于日间动物的双眼是个困难的任务
is too difficult for the eyes of most daytime animals.
但对于夜间动物它们只需要适应一下
But for night creatures, it’s just a matter of adaptation.
它们需要调整尺寸
One of these adaptations is size.
以眼镜猴为例 它们的眼球和大脑
Take the tarsier, whose eyeballs are each as big as its brain,
一般大小是哺乳动物中眼球大脑相对值最大的
giving it the biggest eyes compared to head size of all mammals.
如果人类拥有同等的相对值 我们的眼睛会像葡萄柚一样大
If humans had the same brain to eye ratio, our eyes would be the size of grapefruits.
眼镜猴的大眼球不是为了显得可爱
The tarsier’s enlarged orbs haven’t evolved to make it cuter, however,
而是为了捕捉到尽可能多的光
but to gather as much light as possible.
眼睛越大
Bigger eyes can have larger openings, called pupils,
瞳孔越大晶状体越大
and larger lenses,
越多的光能够聚集在光感器上
allowing for more light to be focused on the receptors.
眼镜猴用巨大的双眼扫描夜间景象
While tarsiers scan the nocturnal scene with their enormous peepers,
而猫用细小闪光的双眼也能做到
cats use gleaming eyes to do the same.
它们使用脉络膜层来获得图像
Cats’ eyes get their shine from a structure called the tapetum lucidum
这个结构在光感器后方
that sits behind the photoreceptors.
这种结构是由多层镜状细胞组成
This structure is made from layers of mirror-like cells containing crystals
细胞中含结晶体 其作用是反射接收的光线传递给光感器
that send incoming light bouncing back towards the photoreceptors
并将光送出眼睛
and out of the eye.
这造成了一种诡异的光流
This results in an eerie glow,
光感器因此有机会再次侦测光子实际上
and it also gives the photoreceptors a second chance to detect photons.
这种结构是车辆远光灯的灵感
In fact, this system has inspired the artificial cats’ eyes we use on our roads.
来源而另一种动物 蟾蜍习惯了慢慢来
Toads, on the other hand, have adapted to take it slow.
它们的眼睛能构成一幅图像
They can form an image
即使每个光感器每秒只能捕捉一个光子
even when just a single photon hits each photoreceptor per second.
秘诀在于它们的光感器比人类的
They accomplish this with photoreceptors
慢了不止25倍
that are more than 25 times slower than human ones.
这意味着蟾蜍能接收光子长达4秒
This means toads can collect photons for up to four seconds,
因此它们在视觉间隔中收集的信息
allowing them to gather many more than our eyes do
比我们更多
at each visual time interval.
这个系统的缺点就是减缓了蟾蜍的反应速度
The downside is that this causes toads to react very slowly
因为它们每四秒才能收到一次信息更新
because they’re only receiving an updated image every four seconds.
幸运的是 它们习惯捕食行动缓慢的猎物
Fortunately, they’re accustomed to targeting sluggish prey.
夜晚充斥着昆虫的鸣叫声
Meanwhile, the night is also buzzing with insects,
比如说鹰蛾
such as hawk moths,
即使夜晚没有任何光源 它们也能看见
which can see their favorite flowers in color, even on a starlit night.
花朵的颜色它们达成这点的方式令人惊奇
They achieve this by a surprising move –
去除视觉接收系统中所有的细节
getting rid of details in their visual perception.
相邻光感器的信息在大脑处理时
Information from neighboring photoreceptors is grouped in their brains,
放在了一起因此每个群组的光子捕捉
so the photon catch of each group is higher
比单一光感器的数量多然而
compared to individual receptors.
以群组为单位的光感器失去了图像的种种细节
However, grouping photoreceptors loses details in the image,
因为完整的细节呈现需要精密网格
as fine details require a fine grid of photoreceptors,
状的光感器每个光感器在每个点都要捕捉到光子
each detecting photons from one small point in space.
这种方法牺牲了细节 平衡光子数量
The trick is to balance the need for photons with the loss of detail
蛾子仍然能找到花朵
to still find their flowers.
无论双眼速度是快是慢 是大是小是亮是暗
Whether eyes are slow, enormous, shiny, or coarse,
是粗是细它们都是生物适应性的组合
it’s the combination of these biological adaptations
给予了夜间动物独一无二的视力
that gives nocturnal animals their unique visual powers.
想象我们通过它们双眼看世界的景象
Imagine what it might be like to witness through their eyes
太阳落下之后夜世界的绮丽
the world that wakes up when the Sun goes down.

发表评论

译制信息
视频概述
听录译者

收集自网络

翻译译者

收集自网络

审核员

自动通过审核

视频来源

https://www.youtube.com/watch?v=t3CjTU7TaNA

相关推荐