2019年高考英语天津卷阅读理解C详解

How does an ecosystem（生态系统）work？What makes the populations of different species the way they are？Why are there so many flies and so few wolves？To find an answer，scientists have built mathematical models of food webs，noting who eats whom and how much each one eats.
一个生态系统是如何工作?是什么促使不同物种的种群成为现在的样子?为什么有那么多苍蝇和如此少的狼?为了找到答案,科学家建立了食物网的数学模型,并指出谁吃谁,吃多少。

With such models，scientists have found out some key principles operating in food webs.
通过这样的模型，科学家们发现了在食物网中起作用的一些关键原理。
Most food webs，for instance，consist of many weak links rather than a few strong ones.
例如，大多数食物网是由许多薄弱环节组成的，而不是由一些强环节组成的。
When a predator（掠食动物）always eats huge numbers of a single prey（猎物），the two species are strongly linked；when a predator lives on various species，they are weakly linked.
当捕食者总是吃大量的猎物,这两个物种息息相关,当捕食者以不同的种类为生,他们是弱相关。