250 million years ago is the Permian extinction.

二大灭绝发生在2.5亿年前。

The bear case rests on patience, a Persian restoration and a Permian boom.

看跌理由在于耐心，波斯恢复和二繁荣。

The Permian event was particularly devastating to sea creatures.

二事件对海洋破坏性尤其严重。

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。

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

导致二大灭绝原因长期以来都没有一个定论。

Presto! The Permian mass extinction is explained.

就这样！这就是二大灭绝解释。

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

在二末期，那场大灭绝带走了超过80%。

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

研究人员说，他们看到了二集群绝灭和如今气候变化问题之间相似之处。

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

在二时期，我们也第一次发现了有开始靠两条腿行走证据。

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二末期。

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，二盆地地表下也绝对覆盖着以前无法触及富含石油页岩。

And then all eyes began once again turning back towards the gigantic Permian Basin over in west Texas.

然后，所有目光又开始转向德克萨斯州西部巨大二盆地。

The acquisition expands Chevron's shale-oil assets in America's Permian basin, where Anadarko is a leading independent operator.

此次收购扩大了雪佛龙在美国二盆地页岩油资产，阿纳达科是该地区领先独立运营商。

Now, dinosaurs did exist in this dry, post-Permian world.

现在，恐龙确实存在于这个干燥后二 世界。

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

但随着二进行，气候变得越来越 热和干燥。

We think something similar was the cause of the end-Permian extinction.

我们认为类似事情是二末灭绝原因。

The cause of the End-Triassic extinction is even murkier than the End-Permian extinction.

三末灭绝原因甚至比二末灭绝原因还要模糊。

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

在二，至少95%从化石记录中得知退了场，再也没有回来。

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

随着在二时期变得更加专业化 ，它们牙齿也变得更加专业化。

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最后一个时期 ，即二，在盘古大陆蔓延。