Animal species disappear because of changes on the Earth that are caused either by nature or by human activities. While nothing can be done about nature, humans can help save many animal species from being extinct.

动物物种的消失是因为由自然或人类活动引起的地球上的变化。虽然人类对自然无能为力，但人类可以帮助挽救许多动物，使它们不被灭绝。

Extinction is a natural phenomenon. After all, more than 90 percent of all animal species that have ever lived on Earth are not alive today, and this has had nothing to do with human beings. Sometimes, a natural event, like a volcanic eruption, can kill an entire species. It is interesting to know that dinosaurs were wiped out by an enormousasteroid impact on the planet around 66 million years ago, in the absence of humans. Animal extinctions may also be caused by natural occurrences such as climate heating or cooling or changes in sea levels. For example, after the ICE Ages, when the glaciers melted and the planet became warmer, many species died out because they could not live in a warmer climate. In these cases, it is indeed senseless for humans to try tointervene and stop them from happening. 

灭绝是一种自然现象。毕竟，在地球上生活过的动物中，有90%以上的物种今天已经不存在了，而这与人类没有任何关系。有时，一个自然事件，比如火山爆发，会杀死整个物种。有趣的是，恐龙在大约6千600万年前被一颗巨大的小行星撞击地球而灭绝（那时根本没有人类）。动物灭绝也可能是由自然现象引起的，如气候变暖或冷却或海平面变化。例如，在冰河时代之后，当冰川融化了，地球变暖了，许多物种消失了，因为它们不能生活在更温暖的气候中。在这些情况下，人类试图干预并阻止其发生是毫无意义的。

Yet this does not mean that human activity is not at all responsible for animal extinction, especially in modern days. Given that it is a natural process of animal species to become extinct, humans have made it worse, and accelerated the extinction. A new study reveals that the famous extinction of Mauritian Dodo about 300 years ago began the moment Dutch sailors first encountered the bird on the island of Mauritius. As a matter of fact, many animal species have been lost due to the human role in habitat loss, environmental pollution, climate change, over-fishing, and over-hunting. Indeed, human activities have made the extinction of many animals take place long before the nature should have taken its course.

然而，这并不意味着人类的活动对动物灭绝完全没有责任，特别是在现代。虽然动物物种灭绝是一个自然过程，但是人类让情况变得更糟了，并加速了灭绝。一项新的研究显示，大约300年前，的毛里求斯渡渡鸟灭绝就是始于荷兰水手次在毛里求斯岛看见这种鸟。事实上，由于人类在栖息地丧失、环境污染、气候变化、过度捕捞和过度狩猎等方面的作用，许多动物物种已经丧失。的确，人类的活动使得许多动物的灭绝在自然时间还远远未到前就发生了。

In conclusion, although it is natural process that many animal species have died out, now there are enough reasons to believe that human beings should (and could) take action to prevent animals from disappearing too soon.

总之，虽然许多动物物种灭绝是一个自然过程，但现在有足够的理由相信人类应该（也可以）采取行动防止动物过早灭绝。

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