250 million years ago is the Permian extinction.

二叠纪大灭绝发生在2.5亿年前。

The Permian event was particularly devastating to sea creatures.

二叠纪事件对海洋动物的破坏性尤其严重。

Presto! The Permian mass extinction is explained.

就这样！这就是二叠纪物种大灭绝的解释。

The synapsids divided into four streams, only one of which survived beyond the Permian.

下孔亚纲分成四支，只有一支闯过了二叠纪。

At the end of the Permian, the extinction figure was more than 80%.

在二叠纪末期，那场大灭绝带走了超过80%的物种。

The idea that an impact caused the Permian extinction has been around for a while.

导致二叠纪大灭绝的原因长期以来都没有一个定论。

The researchers said they see similarities between the Permian mass extinction and today's climate change problem.

研究人员说，他们看到了二叠纪集群绝灭和如今气候变化问题之间的相似之处。

Here in the Permian, we also start to see the first evidence of walking on two legs.

在二叠纪时期，我们也第一次发现了有些动物开始靠两条腿行走的证据。

The event took place at the end of what Earth scientists, or geologists, call the Permian Period.

这一事件发生在地球科学家或地质学家所说的二叠纪末期。

It followed after Earth's worst mass extinction 252 million years ago at the end of the Permian Period.

在2.52亿年前地球上最严重的大灭绝之后，紧随着就是二叠纪末期。

In the Permian, at least 95 percent of animals known from the fossil record check out, never to return.

在二叠纪，至少95%从化石记录中得知的动物退了场，再也没有回来。

And as it turned out, the Permian too was absolutely covered with previously inaccessible petroleum-rich shale rocks beneath the surface.

而事实证明，二叠纪盆地的地表下也绝对覆盖着以前无法触及的富含石油的页岩。

252 million years ago, between the Permian and Triassic periods, the Earth's land masses gathered together into the single supercontinent Pangaea.

52亿年前， 在二叠纪和三叠纪时期之间，地球上的陆地聚集 成 一个超级大的盘古大陆。

Toward the end of the Permian, the planet became increasingly dry.

在二叠纪末期，地球变得越来越干燥。

As animals got more specialized during the Permian Period, so did their teeth.

随着动物在二叠纪时期变得更加专业化 ，它们的牙齿也变得更加专业化。

As the Permian progressed, amniote predators like Dimetrodon, Ophiacodon, and eventually saber-toothed gorgonopsians became widespread.

随着二叠纪的进展，羊膜动物捕食者如异齿龙、蛇夫和最终的剑齿蛇目动物变得普遍。

First was the Permian-Triassic extinction 252 million years ago -- aka the Great Dying.

首先是 2.52 亿年前的二叠纪-三叠纪大灭绝 ——也就是大灭绝。

And both groups spent the last period of the Paleozoic, the Permian, spreading across Pangea.

这两个群体都度过了古生代的最后一个时期 ，即二叠纪，在盘古大陆蔓延。

But as the Permian went on, the climate got hotter and drier.

但随着二叠纪的进行，气候变得越来越 热和干燥。

During the Permian Period, something big was happening on Earth.

在二叠纪时期，地球上发生了一件大事。