【英语时差8,16】自杀生存战略

Beneath the surface of a pond or stream it's a fish-eat-fish world, and the tiny minnow is often lunch for larger fish such as pike.   You'd think a tasty minnow would try to remain inconspicuous, but this isn't always the case. If a minnow's skin is damaged by an attacking pike, it releases a chemical that attracts more pike. Why would a minnow that's already being attacked want to attract more trouble? Do injured minnows have some kind of crazy death wish?

This seemingly suicidal behavior is actually a clever survival strategy. The minnow's chemical has two distinct functions. First, it warns other minnows about the danger. Minnows travel in schools with close relatives, so this chemical alarm warns the others away from potentially dangerous waters. Even if the original minnow is eaten, its brothers and sisters will live to reproduce. From a genetic¹ standpoint, this self sacrifice makes sense.

You might wonder about the chemical's other function though--to attract more pike. A minnow's skin is most likely to be damaged in an attack from a relatively² small pike. Larger pike simply swallow their minnows whole. Because of this, the alarm substance is usually released when a small pike is attacking. This means that the chemical might well attract pike that are larger than the minnow's current assailant. Pike have no qualms³ about eating other pike, so if a big one sees a smaller pike chasing a tiny minnow, that big pike will go after the larger mouthful, allowing the minnow to escape.

It's much like the end of Jurassic Park. The humans were about to be eaten by evil velociraptors, when the noise of their struggle summoned a bigger predator⁴: Tyrannosaurus Rex. T-rex ate the raptors, allowing the humans to escape. 

1 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

2 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

3 qualms   

n.不安；内疚

参考例句：

• He felt no qualms about borrowing money from friends.他没有对于从朋友那里借钱感到不安。
• He has no qualms about lying.他撒谎毫不内疚。

4 predator   

n.捕食其它动物的动物；捕食者

参考例句：

• The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
• Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴，它是一种令人恐惧的捕食性动物。