山西省2017高考英语二轮复习专题训练：阅读理解（35）_高考复习指南

山西省2017高考英语二轮复习专题训练：阅读理解（35）

　　Now let’s look ourselves as a species in relation to ecosystem balance．Modern scientists believe that humankind，like other animals，evolved(进化)through millions of years of changes and adaptations to the environment and that our most direct evolutionary ancestor was probably all earlier species of the primate(monkey ,ape)group．Despite this similarity with other creatures，however ,the evolution of humankind differs from that of other species in one important and unique way．

　　In other species evolution has led to specialization．both in the species abilities and in its place within the environmental structure．For example．the giraffe is much adapted to feeding on treetops，but it is also specialized and thus limited to feeding on trees and shrubs(灌木)．Only with great difficulty can it bend down to graze on the ground．Similarly, the anteater is extremely well adapted to eating ants but is unable to catch or eat other animals．The same is true for countless other species．

　　For humankind it is opposite．Our evolution had led to a very generalized ability．Our highly developed intelligence and ability to make and handle tools mean that we can do almost anything．Humans evolved in such a way that we are able to move into every environment on Earth and even into space．No natural competitor offers great resistance，and other natural enemies such as disease have been controlled．