This break in Earth's history is marked by a mass extinction, when as many as half the species on the planet became extinct.

地球历史上的这次重大灾难以物种的大量消亡为标志；当时，地球上多达一半的物种都灭绝了。

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There is no natural foresight, no mechanism for warning that present selfish gains are leading to species extinction - and indeed, 99 per cent of all species that have ever lived are extinct.

没有自然的深谋远虑，没有什么机制会警告当前的自私收益将导致物种灭绝——事实上，99%曾经存在的物种现在都已经灭绝了。

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So far, only one to two percent of all species have gone gone extinct in the groups we can look at clearly, so by those numbers, it looks like we are not far down the road to extinction.

迄今为止，在我们能清楚了解的物种中，只有1%到2%真正灭绝。 从这点来看，我们似乎在物种灭绝的路上还未走远。

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Besides bringing new species to the textbooks - and relegating them immediately to the "extinct" category - the study sheds new light on the extinction event, widely thought to have been caused by an enormous asteroid impact at the end of the Cretaceous period, about 65.5 million years ago.

BBC: Obama-named lizard was wiped out with the dinosaurs