An animal species becomes extinct when it fails to produce enough young is each generation to keep pace with the death-rate. We can tell from fossil evidence in rocks that many living species have become extinct over the millions of years since life began. It is a natural process and extinction is the fate of many animal that has specialized too far to change when its environment changes， or has to compete with a better-adapted and more powerful animal. Because of remarkable technical developments during the past few centuries， man has destroyed or nearly destroyed some species by killing them at such a rate that they couldn’t produce enough offspring， or by completely changing their natural environment at surprising speed.
不论何种动物，只要每一代不能繁殖出足够的后代，不能与这种动物的死亡数字相平衡，那么这种动物就会逐渐灭绝。我们从岩石中的化石遗留下的证据中可以辨别出来，自从地球上有生命时开始，在若干个百万年中，有很多动植物的物种已经逐渐地灭绝了。任何一种生物过于特殊化以致于不能随着环境的变化而改变自己的特性的动物，或者是任何一种必须与一种能更好地适应环境而又更加强大的动物相竞争的动物，它们的命运都将是灭绝，这是个很自然的演化过程。由于最近几百年来各项科学技术的迅猛发展，以惊人的速度大量杀死了某些种动物，或以惊人的速度彻底改变了这些动物的生存的自然环境，致使这些动物不能生育繁衍出足够的后代，人类已经消灭了或已经接近于消灭了某些种动物。

Many people are concerned about animals and wildlife conservation. One way to preserve species under threat of extinction - whatever the cause - is to remove them to zoos and parks and breed them there. There is always the chance that enough offspring will be born to return them one day to their natural environment - provided it still exists， and that hunters don’t kill them again！ Another method is to protect the animals in their natural environment by creating wildlife reserves and parks and using game wardens to look after them. But the parks are large， the wardens few and the determination of hunters very great. Early in 1980 wardens and hunters clashed in East Africa. The hunters were armed with modern weapons and several people were killed.
许多人都关心动物及野生动植物的保护工作。不管是什么原因造成了灭绝，一种保存遭受灭绝威胁的物种的办法就是把这些物种搬进动植物园里面去，并让这些动植物在那里生息繁衍下来。假如这种动物能存活下来，假如猎手们不再杀死它们，那么等将来它们繁衍出足够的后代之后，总会有这样的机会，总有一天会让它们到大自然的环境中去！另一种在自然环境中保护动物的办法，就是创建野生动植物保护区和野生动植物园并设置禁止渔猎野生动物监督官来看护这些动物。但是野生动植物园范围很广大，禁止渔猎野生动物监督官人手又很少，偷猎野生动物的猎人们的偷猎决心都很大。1980年初监督官与猎手们发生了冲突。猎手们都装备有现代化的武器，结果有数人在冲突中死亡。

There is great pleasure in watching wildlife in natural or near-natural environments， and tourism can add to the income of countries. The animals are still resources - but in a very different form.
在大自然当中或在接近于大自然的环境当中，欣赏野生动植物，真是一大赏心乐事，况且这种旅游观光业也能为国家或地方增加收入。各种动物都依然是我们的资源--但却是一种不同形式的资源。