Airborne soot and dirt from the impact blanketed Earth, inhibiting photosynthesis and triggering mass extinction of species.
撞击产生的烟尘和灰尘覆盖了地球，抑制了光合作用，引发了物种的大规模灭绝。
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。
Following each mass extinction, there is a sudden evolutionary burst as new species develop to fill the ecological niches opened by the event.
在每一次物种大灭绝后，都有一次突然的进化爆发，因为会有新物种出现来填补灭绝创造的生态位。
Each mass extinction may have had a different cause.
每一次大灭绝可能都有不同的原因。
This is the story of wildlife conservation in the age of mass extinction.
这是个关于在大规模的物种灭绝时代保护野生动物的故事。
The mass extinction would have occurred very suddenly under this hypothesis.
在这种假设下，大灭绝的发生是非常突然的。
Many scientists have therefore concluded that a sixth great mass extinction is currently in progress.
因此，许多科学家得出结论，第六次大规模物种灭绝正在发生。
If you think about it though, the core problem with this sixth mass extinction is human interference.
如果你仔细想想，这第六次大灭绝的核心问题是人类的干扰。
As Permian life-forms declined, they reached a fatal threshold and species succumbed to mass extinction.
随着二叠纪生命形式的衰退，它们达到了一个致命的临界点，物种最终走向了大灭绝。
Scientists have linked the mass extinction at the end of the Cretaceous with a meteorite impact on Earth.
科学家将白垩纪末期的大灭绝与地球上的陨石撞击联系起来。
Evidence points to hunting by humans and habitat destruction as the likely causes for the current mass extinction.
有证据表明，人类的捕猎和栖息地的破坏可能是导致当前物种大量灭绝的原因。
Presumably, those environmental disasters could have been responsible for the mass extinction, including the death of the dinosaurs.
据推测，这些环境灾难可能是物种大规模灭绝的成因，包括恐龙的灭绝。
Roughly 250 million years ago, in the worst series of mass extinction in Earth's history, almost all species of life simply vanished.
大约2.5亿年前，在地球历史上最严重的一系列大灭绝中，几乎所有的生命物种都消失了。
Today we are witnessing a sixth mass extinction, but unlike the others, the current loss of bio-diversity can be traced to human activity.
今天，我们正在见证第六次物种大灭绝，但与其它几次不同的是，目前生物多样性的丧失可以追溯到人类活动。
Various theories seek to explain this mass extinction.
对于这次大灭绝，有很多种解释。
But the Mesozoic, too, began with a mass extinction.
但中生代本身便是以一次大灭绝开始的。
Before the mass extinction, the top ocean predators were primitive sharks.
在大规模灭绝之前，高等海洋肉食生物是远古的鲨鱼。
First, that there was not one mass extinction at the end of the Permian, but several.
第一，在二叠纪结束的时候并不是一个大规模灭绝，而是好几个。
This marks precisely—to within a few thousand years—the point of mass extinction on the land.
这明确标志着正是在这几千年中，发生了陆地上的大规模灭绝。
Yet the mass extinction, however remote, that should be concentrating minds is that of mankind.
然而鱼类的大规模灭绝，无论如何遥远，也应该是人类集中精神所要考虑的一件事。
The mass extinction event killed off the dinosaurs and many other animal and plant species.
中找到了元素铱岩层，而这通常会被发现于小行星中。 这次灭绝事件杀光了恐龙以及许多其他动植物物种。
Of course, humanity is currently setting off the sixth mass extinction event in Earth's history.
当然，人类正在引发地球历史上第6次物种大灭绝。
Permian-Triassic The worst mass extinction took place 250m years ago, killing 95% of all species.
二叠纪-三叠纪最严重的大灭绝发生在两亿五千万年以前，杀死了所有物种的95%。
In this movie, a comet miles across is headed toward Earth, sure to cause a mass extinction if it hits.
在这部影片里，以颗直径几英里的彗星直奔地球而来，一旦撞上，就会是天崩地裂的大灾难。
None of it lines up to say a mass extinction and there is very little evidence to say humans drove the extinction.
没有一个数据指出曾有一次大规模的灭绝，而且很少有证据说是人类导致它们的灭绝。
None of it lines up to say a mass extinction and there is very little evidence to say humans drove the extinction.
没有一个数据指出曾有一次大规模的灭绝，而且很少有证据说是人类导致它们的灭绝。
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