There's bacteria, there's algae..., vascular plants.

有细菌，有藻类，有维。

Another type of seedless vascular plant is ferns, also known as monilophytes.

另一种无维是蕨类，也被称为单生。

We're talking bryophytes and seedless vascular plants, the categories that include mosses and ferns, liverworts, and more.

我们说的是苔藓和无维，这类包括苔藓、蕨类、苔类等。

As you can tell, bryophytes and seedless vascular plants are not simply low-to-the-ground lurkers.

正如你所知，苔藓和无维并不是简单的地下潜伏者。

Although many of the early seedless vascular plants have gone extinct, you can still find some of them growing today.

虽然许多早期的无维已经灭绝了，但你仍然可以发现它们中的一些生长。

When Prototaxites first arrived on the scene, 420 million years ago, vascular plants had just begun to colonize the land.

4.2 亿年前，原紫杉首次出现时，维束才刚刚开始这片土地上定居。

Huge forests full of ferns, mosses, and some of the earliest vascular plants had taken over much of the planet.

长满蕨类、苔藓和一些最早的维束的巨大森林占据了地球的大部分地区。

Well, the bryophytes and seedless vascular plants were some of the first plants to arise from that event — and many of them still exist today!

苔藓和无维是第一批从那次事件中产生的，其中许多仍然存！

But, they were the first plants to form true roots, stems, and leaves that contain vascular tissue, so they're considered the first vascular plants.

但是，它们是第一批形成真正的根、茎和含有维组织的叶子的，所以它们被认为是第一批维。

Next time, we'll be using these tools to uncover the history of plants, starting with bryophytes and seedless vascular plants, some of the earliest plants on Earth.

下节课，我们将用这些工具来揭开的历史，从苔藓和无维开始，它们是地球上最早的。

So big, complex life on land -- like vascular plants -- probably wouldn't have been possible if Tortotubus and its fungal predecessors hadn't prepared the land first.

如果 Tortotubus 及其真菌前辈没有首先准备土地，那么陆地上如此庞大、复杂的生命——如维——可能是不可能存的。

So, a few hundred million years later, a cousin of the bryophytes showed up, Seedless Vascular Plants forming another branch on the plant family tree: seedless vascular plants.

因此，几亿年后，苔藓的表亲无维出现了，形成了家族树的另一个分支：无维。

The nutrients themselves could come from conventional crops, but Dr Post also has plans to use algae, which grow faster than vascular plants, to provide the necessary amino acids, sugars and fats.

那些营养质可以从普通农作中获取，但Post博士计划使用藻类，因为它们比那些维长的要快，以此提供所需的氨基酸、糖类和脂肪。

The three main organs that comprise a plant body are stems, leaves, and roots, and their presence is one of the defining characteristics of a category called vascular plants.

组成体的三个主要器官是茎、叶和根，它们的存是维的一个决定性特征。

But lycopods were also the earliest vascular plants, which means they were the first plants to contain xylem, a special tissue that moves water and nutrients from the roots to the leaves.

但石松属也是最早的维，这意味着它们是最早含有木质部的，木质部是一种特殊的组织， 可以将水分和养分从根部输送到叶子。

On top of that, seedless vascular plants — and all plants that evolved after them — have a dominant sporophyte, meaning that what we tend to recognize as the plant is actually its sporophyte generation.

最重要的是，无维——以及它们之后进化的所有——都有一个显性的孢子体，这意味着我们倾向于认为的实际上是它的孢子体一代。

Having a dominant sporophyte introduced lots of advantages — like, while the spore-making generation of a bryophyte couldn't grow very far off the ground; the sporophytes of seedless vascular plants could grow much taller and larger, with more room for spore-producing organs.

拥有一个优势孢子体带来了很多好处——比如，苔藓的产孢体不能长得离地面很远；而无维的孢子体可以长得更高更大，有更多的空间容纳产孢器官。