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

有细菌，有藻，有维管。

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

另一种无维管，也被称为单生。

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

我们说苔藓和无维管，这包括苔藓、、苔等。

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

正如你所知，苔藓和无维管并不简单地下潜伏者。

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

虽然许多早期无维管已经灭绝了，但你仍然可以发现它们中一些在今天生长。

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，维管束才刚刚开始在这片土地上定居。

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

长满、苔藓和一些最早维管束巨大森林占据了地球大部分地区。

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!

苔藓和无维管第一批从那次事件中产生，其中许多今天仍然存在！

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，它们第一批形成真正根、茎和含有维管组织叶子，所以它们被认为第一批维管。

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历史，从苔藓和无维管开始，它们地球上最早。

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、复杂生命——如维管——可能不可能存在。

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，苔藓表亲无维管出现了，形成了家族树另一个分支：无维管。

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，因为它们比那些维管长要快，以此提供所需氨基酸、糖和脂肪。

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.

组成体三个主要器官茎、叶和根，它们存在维管一个决定性特征。

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.

但石松属也最早维管，这意味着它们最早含有木质部，木质部一种特殊组织， 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，无维管——以及在它们之后进化所有——都有一个显性孢子体，这意味着我们倾向于认为实际上它孢子体一代。

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，苔藓产孢体不能长得离地面很远；而无维管孢子体可以长得更高更大，有更多空间容纳产孢器官。