Life recovers, and then we're in the Devonian period after that.

生命恢复了，然后我们进入泥盆纪。

The long-ago seas of the Carboniferous and Devonian swarmed with tiny plankton that wrapped themselves inside tiny protective shells.

泥盆纪和石炭纪的古代海洋里生活着大批微小的浮游生物。它们躲在小小的保护性壳里。

The clue to this ancestor, it was assumed, would be found in the Devonian era, from about 400 million years ago.

据认，祖先的线索要在大约4亿年以前的泥盆纪寻找。

Going back even further, we find the Late Devonian extinction about 360 million years ago.

再往前追溯， 我们发现大约 3. 6 亿年前的晚泥盆世大灭绝。

The Ordovician (440 million years ago) and Devonian (365 million) each wiped out about 80 to 85 percent of species.

奥纪（44000万年以前）和泥盆纪（36500万年以前）分别消灭了大约80%——85%的物种。

Well, during the Devonian, things were … complicated.

好吧，在泥盆纪期间，事情… … 很复杂。

The venerable family of Roach has been crawling around since at least the devonian.

至少从泥盆纪，敬的 Roach 家族就一直在四处爬行。

And Archaeopteris and other Devonian plants also  created more habitats for animals, and more food for them, too.

祖蕨属和其他泥盆纪植物也动物创造了更多的栖息地，也它们创造了更多的食物。

But these creatures lived in a very different world from the Devonian.

但些生物生活在 与泥盆纪截然不同的世界中。

While fish with jaws first appeared in the Silurian, they proliferated in the Devonian.

虽然有颚的鱼最早出现在 志留纪，但它们在泥盆纪大量繁殖。

But in the Devonian, a new branch of the cephalopod family tree appeared: ammonites.

但在泥盆纪，出现了头足类 家族树的一新分支：菊石。

By the end of the Devonian, all of the giant marine eurypterines had gone extinct.

到泥盆纪末期，所有巨大的海洋广翅目动物都灭绝了。

By the end of the Devonian period, plants had developed almost all of  the traits they would need to thrive.

到泥盆纪末期，植物已经发展出它们茁壮成长所需的几乎所有特征。

But things started to change about a  quarter of the way into the Devonian Period.

但在进入泥盆纪的大约四分之一时，情况发生变化。

It's not really clear what caused the Devonian extinctions, which occurred in two main bursts.

目前还不清楚是什么导致了泥盆纪的物种灭绝，它发生在两次主要的爆发中。

Oxygen levels in the Devonian and Carboniferous periods, when terrestrial life first bloomed, were as high as 35 percent (as opposed to nearer 20 percent now).

在陆地生命大幅度增加的泥盆纪和石炭纪，空气中的氧的浓度高达35%（现在是将近20%）。

Fish began their transition onto land 400 million years ago, during in the Devonian period.

4 亿年前，在泥盆纪时期，鱼类向陆地过渡。

And the wood in these plants was  directly responsible for a lot of the soil generation that  took place in the Devonian.

些植物中的木材直接导致了泥盆纪发生的大量土壤生成。

The Devonian seas were peopled by animals of these species, and deposited them by thousands in the rocks of the newer formation.

泥盆纪海洋中栖息着些物种的动物，并将成千上万的它们沉积在较新地层的岩石中。

So, while they helped end  the world of the Devonian, if it wasn't for them, our world  might not have gotten started.

因此，虽然他们帮助终结了泥盆纪世界，但如果不是他们， 我们的世界能就不会。