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Using the examples of the eel and the angler fish,
请以鳗鱼和鮟鱇鱼为例，
explain two types of adaptations that help animals survive in the deepest parts of the ocean.
解释动物为了在深海生存而进化出的两种机能。
Listen to part of a lecture in a marine biology class.
请听海洋生物学课上的部分内容。
A lot of plants and animals live near the surface of the ocean,
许多植物和动物都生活得靠近海洋表面，
and that means there's a lot of food near the surface,
而这就意味着海洋表面附近有很多食物，
because there's lots of plants and animals to eat.
因为有很多动植物可以食用。
But if you go down to the deepest parts of the ocean,
但是，在海里最深的地方又冷又暗，
it's cold and dark, and there's not a lot living down there, so food is very scarce.
没有多少生物，所以食物很是稀缺。
So organisms that live down at these great depths have developed special adaptations
所以，生活在深海区的生物体都进化出了特别的机能
to help them survive in this environment where food is so hard to find.
以在这个食物稀缺的环境中生存下去。
For example, many deep-sea organisms have body features that enable them to eat prey that are larger than themselves.
比如说，很多深海生物的身体特征能使它们吃下比它们自己还大的猎物。
A good example, um, there's a species of eel
一个很好的例子就是一种鳗鱼，
that has an enormous mouth and a large stomach that's capable of expanding.
这种鳗鱼长着一张巨大的嘴，和一个可以扩张的大胃。
And these unusual features allow this eel to eat prey larger than itself.
这些不寻常的身体特征使得这种鳗鱼可以吃下比它大的猎物。
That's a big advantage because if the eel eats something big,
那是一个很大的优势。因为如果鳗鱼吃下了某个很大的猎物，
that's a lot of food, a lot of nutrition.
就意味着它吃下了很多食物，获得了很多营养。
So the eel can go for quite a while before it has to find food again.
所以鳗鱼可以很长时间不用寻找食物。
Another helpful adaptation in some deep-sea organisms is the ability to generate light.
一些深海生物进化出的另一项有用的机能就是可以发光。
And some organisms use that light to help them capture food.
这些生物会利用自己发出的光来抓住猎物。
For example, there's a kind of fish called the angler fish.
比如，有一种鱼叫做鮟鱇鱼。
And on its head, this fish has a little structure that produces light that glows in the dark.
它的头上长着一个可以在黑暗中发出光亮的小物体。
This little structure, this little light, is positioned close to the fish's mouth.
这个小物体像个小灯笼一样，长得离这种鱼的嘴巴很近。
Other fish are attracted to this light,
别的鱼会被这个小灯笼吸引过来，
they think it's something small they can eat, so they swim straight toward it.
它们以为看到了某个可以吃的小东西，就径直游了过来。
And that brings them close enough for the angler fish to capture them and eat them.
这样它们离鮟鱇鱼就越来越近，近到鮟鱇鱼可以抓住它们并把它们吃掉。
