Name: 維管束植物=贏家- 生物學速成班 #37 (Vascular Plants = Winning! - Crash Course Biology #37)
Uploaded: 2021-01-14T04:21:16.000Z
Duration: 11 min 54 s
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Its feathery leaves have natural astringent properties,

and its scientific name, Achillea, comes from Achilles, the Greek

hero, who is said to have used it on the wounds of his soldiers.

And this is snakegrass, also known as horsetail or, to the kids,

popgrass, because you can just pop it apart, and then put it

back together again. Although on top there, it's dead now.

And this is a ponderosa pine, one of my favorite trees.

and on a warm day if you sniff it, it smells like butterscotch.

They all have different shapes, sizes, and properties,

but each of these things is a vascular plant, one of the most

diverse and, dare I say, important families in the tree of life.

Since their predecessors first arrived on the scene some

420 million years ago, vascular plants have found tremendous

success through their ability to exploit resources all around them.

They convert sunshine into food. They absorb nutrients directly

through the soil without the costly process of digestion.

And they even enlist the help of some friends when it comes

to reproduction, so often when they're doing their thing it

involves a third party. Which, y'know, good for them.

explain vascular plants' extraordinary evolutionary success.

And as we learned last week, nonvascular plants have reproductive

strategies that are tricked out six ways from Sunday.

The secret to vascular plants' success is in their defining trait:

conductive tissues that can take food and water

from one part of a plant to another part of a plant.

This may sound simple enough, but the ability to move stuff

from one part of an organism to another was a

huge evolutionary breakthrough for vascular plants.

It allowed them to grow exponentially larger,

store food for lean times, and develop some fancy features

that allowed them to spread farther and faster.

It was one of the biggest revolutions in the history of life on Earth.

The result? Plants dominated Earth long before

And even today, they hold most of the world records:

The largest organism in the world is a redwood

Bigger than 3 blue whales laid end to end.

The most massive organism is a grove of quaking aspen in Utah,

all connected by the roots, weighing a total of 13 million pounds.

We've spent a lot of time congratulating ourselves

on how awesomely magnificent and complex the human animal is,

So you know by now, the more specialized tissues an organism has,

the more complex they are and the better they typically do.

But you also know that these changes don't take place overnight.

The tissues that define vascular plants didn't evolve all at once,

outermost layers and help prevent damage and water loss.

conducting of materials I just mentioned.

And the most abundant tissue type, ground tissues,

carry out some of the most important functions of plant life,

including photosynthesis and the storage of leftover food.

Now, some plants never go beyond these basics.

This is called primary growth, and plants that are limited

small, soft and flexible, and typically they die down to the root,

or die completely, after one growing season.

Pretty much everything you see growing in a backyard garden:

herbs, flowers, broccoli and that kind of stuff,

But a lot of vascular plants go on to secondary growth,

which allows them to grow not just taller but wider.

This is made possible by the development of additional tissues,

These are your woody plants, which include shrubs,

bark-covered vines called lianas, and of course, your trees.

But no matter how big they may or may not grow,

all vascular plants are organized into three main organs,

all of which you are intimately familiar with, not just because

you knew what they were when you were in second grade,

but also because you probably eat them every day.

First, the root. It absorbs water and nutrients,

and serves as a pantry of leftover food, and of course,

Next, the stem. It contains structures that transport fluids,

stores nutrients, and also is home to specialized cells

called meristems that are responsible for creating new growth.

But their most important task is to support the last organ:

The leaf. This, of course, is where the plant exchanges gases

with the atmosphere and collects sunlight to manufacture food,

with the help of water and minerals collected through the root

Now, each of these organs contains all three tissues,

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維管束植物=贏家- 生物學速成班 #37 (Vascular Plants = Winning! - Crash Course Biology #37)

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