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

有细菌，有藻类，有管植物。

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

另一种无管植物是蕨类植物，为单生植物。

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

我们说是苔藓植物和无管植物，这类植物包括苔藓、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，苔藓植物和无管植物并不是简单地下潜伏者。

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

虽然许多期无管植物已经灭绝了，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，管束植物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.

长满蕨类植物、苔藓和一些最管束植物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!

苔藓植物和无管植物是第一批从那次事件中产生植物，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.

但是，它们是第一批形成真正根、茎和含有管组织叶子植物，所以它们认为是第一批管植物。

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植物历史，从苔藓植物和无管植物开始，它们是地球上最植物。

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——如管植物——可能是不可能存在。

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，苔藓植物表亲无管植物出现了，形成了植物家族树另一个分支：无管植物。

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.

那些营养物质可以从普通农作物中获取，但Post博士计划使用藻类，因为它们比那些管植物长要快，以此提供所需氨基酸、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.

组成植物体三个主要器官是茎、叶和根，它们存在是管植物一个决定性特征。

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.

但石松属是最管植物，这意味着它们是最含有木质部植物，木质部是一种特殊组织， 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.

最重要是，无管植物——以及在它们之后进化所有植物——都有一个显性孢子体，这意味着我们倾向于认为植物实际上是它孢子体一代。

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，苔藓植物产孢体不能长得离地面很远；而无管植物孢子体可以长得更高更大，有更多空间容纳产孢器官。