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

盆石炭古代海洋里生活着大批微小浮游生物。它们躲在小小保护性壳里。

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

据认为，这个祖先线索要在大约4亿年以盆寻找。

Well, during the Devonian, things were … complicated.

好吧，在盆期间，事情… … 很复杂。

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

但这些生物生活在 与盆截然不同世界中。

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

虽然有最早出现在 志留，但它们在盆大量繁殖。

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

奥陶（44000万年以）盆（36500万年以）分别消灭了大约80%——85%物种。

But about 385 million years ago, in the Devonian Period, tetrapods started venturing away from the water's edge.

但大约 3.85 亿年， 在盆时期，四足动物开始冒险离开水边。

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

但在盆，出现了头足类 家族树一个新分支：菊石。

And the evolution of armor may seem like an obvious adaptation for protection, especially in the Devonian's crowded seas.

盔甲进化似乎是对保护明显适应，尤其是在盆拥挤海域。

Once plant life started to spread and diversify on land in the Devonian Period, fungi were there to help again.

一旦植物生命在盆时期开始在陆地上传播多样化，真菌就会再次提供帮助。

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

目还不清楚是什么导致了盆物种灭绝，它发生在两次主要爆发中。

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

这些植物中木材直接导致了盆发生大量土壤生成。

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

盆海洋中栖息着这些物种动物，并将成千上万它们沉积在较新地层岩石中。

Because, at this point in the Devonian,   holding onto water was a real challenge.

因为，在盆这个时候，抓住水是一个真正挑战。

Take, for example, that plant I mentioned  earlier: Archaeopteris from the late Devonian.

以我之提到植物为例：盆晚期古蕨属。

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盆石炭，空气中氧浓度高达35%（现在是将近20%）。

So armored fish came in a variety of shapes and sizes during the Silurian and Devonian, from tiny Heterostracans to massive Placoderms.

因此，在志留盆期间， 装甲形状大小各不相同，从微小异类到巨大盾皮。

The Devonian is often known as " The Age of Fishes" - the time when things like Dunkleosteus ruled the waves.

盆通常被称为“类时代”——邓氏等生物统治海浪时代。

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

但在进入盆大约四分之一时，情况开始发生变化。

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

到盆末期，植物已经发展出它们茁壮成长所需几乎所有特征。