Notes

Section 1
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TEACHER: You know that nonvascular and seedless vascular plants differ and that nonvascular plants are all seedless, but vascular plants can either be seed or seedless. Here you see an example of a nonvascular seedless plant. Can you identify it? It looks like this lion, the statue, has green mane and green fur on its back,
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but if you look closer, you can tell that that's just moss. And you've probably seen moss growing on statues or even on the sidewalk, or in cracks of the sidewalk. Moss, a nonvascular seedless plant, is able to grow on this statue. So why don't we see seedless vascular plants, like ferns popping up on its back? Well, that's one of the things that we're
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going to find out as we examine the characteristics and compare and contrast seedless plants.
Section 2
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TEACHER: Recall, all nonvascular plants are seedless. Both nonvascular plants and seedless vascular plants do not produce seeds. Instead, what they have to reproduce are spores. Now, that's a term you've probably heard before. But the actual definition of a spore is a reproductive cell that's resistant to harsh conditions
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and capable of developing into an adult, without fusing with another cell. So all on its own, that spore can grow into maturity and become an adult plant. Here you can see masses of spores on the underside of a fern leaf or a frond, as they're called. They look like little, tiny grains of sand. Each of these little spores is so tiny and so lightweight
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that it can easily travel on the wind or in water. Now, what happens once it has reached maturity and gone off into the wind or in water? That's what we're going to look at. So let's take a closer look at the life cycle of plants that produce spores. Now, there are two major stages that these plants go through, the sporophyte, take a look at this diagram here,
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and the gametophyte, down here. And we'll just sort of walk through this. Now, this is a cycle, so we could technically start anywhere. But since there's number 1 on our diagram, let's start here with the sporophyte stage. In the sporophyte stage, the plant produces spores, that as you know,
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travel in the wind or water. And if they find a place that is suitable for them to grow, they can grow into a plant. And remember, they can resist spores are tough. They can resist harsh conditions. So if the conditions aren't quite right, they can actually wait in sort of a dormant, sleepy state until conditions are right and then grow.
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The spores then grow into plants that are in the gametophyte stage. And gametophyte plants produce two different kinds of sex cells, sperm and egg cells. The sperm cells of one gametophyte will swim to the cells of the egg cells of another gametophyte. And here you can see this.
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Here they are, swimming over to the egg cell. Now, since they're swimming, obviously, we know that in order to swim, you have to be in water, which means whether they're vascular or nonvascular, any spore-producing plant needs to live in a moist environment near water, in order for the sperm cell to fertilize the egg cell and form what comes next this zygote.
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Once it fertilizes, then it's considered a zygote. And a zygote will grow into a new plant, which is now in the sporophyte stage again. And then the cycle continues all over again. Now, it's important to note that this is a general diagram. There are many different kinds of species, so each individual stage might look slightly different for different types of species.
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But the overall process is the same for the life cycle of plants with spores.
Section 4
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TEACHER: We've seen how nonvascular plants and seedless vascular plants are similar. Now let's take a closer look at how they're different. Let's start with looking at the nonvascular plants. Here's a great example. In this image, we see some moss. This is a nonvascular plant, and it has no vascular tissue
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to aid in the transport of water and nutrients. So we have no vascular tissue hence the name "nonvascular plants". Since nonvascular plants must transfer the nutrients from cell to cell, they tend to be very small in fact, only up to about 5 centimeters or a couple of inches tall. You can see that here with the moss.
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Also, they must live in very moist environments so they can absorb water and nutrients directly from their surroundings. Nonvascular plants have no true roots, stems, or leaves, although they do have some structures that might look like these. So if you take a look at this image, we'll identify some of them.
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They do have small, leaf-like structures that you can see in the gametophyte stage right here. So those are just leaf-like structures. What looks like a stem is actually a stalk. And this is the sporophyte stage, growing out of the gametophyte stage. And then at the very top you see something that's called a capsule, and this contains the spores.
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So right here, there's sort of a collection of them. Those are all capsules. Below the plant, if we were to pry this moss up off the rock, there's a thin, thread-like structure that holds the plant to the rock or a bit of soil. And these are called rhizoids. So they are root-like structures that anchor the nonvascular plant and absorb water and nutrients.
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So there are our rhizoids. Now, let's take a look at seedless vascular plants. Seedless vascular plants differ from nonvascular plants in several ways due to the presence of vascular tissue. There are two different types of vascular tissue. The xylem is a type of vascular tissue that transports the water and nutrients throughout the plant. And we can see that in this cross section
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of a stem in the red. So let's draw a little arrow here from the xylem to these red cells. There's the xylem. The second type is phloem, and phloem is a type of vascular tissue that transports food throughout the plant. And the phloem is the light green cells in this image,
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just on the outside of the xylem, found right there. These vascular tissues have strong cell walls which provide support and strength for the plant. As a result, the plant can grow much larger and much farther away from water sources than nonvascular plants. While seedless vascular plants are able to live farther from water sources, they're still found in moist environments
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because there must be water present to allow the sperm and egg cell to fertilize during the gametophyte stage. Seedless vascular plants also have true roots, stems, and leaves.
Section 6
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TEACHER: You now know how nonvascular plants and seedless vascular plants are both alike and different. Take a look at these seedless vascular plants. These are ferns, and they are enormous. There was a time when Earth was covered with giant ferns like these. The Carboniferous period, also called the Age of the Ferns.
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Most ferns now only grow a few feet from the ground. In fact, if you want to see giant ferns like this, you have to go to New Zealand, where this image was taken. Ferns are only one example of seedless vascular plants. Next we'll identify several examples of nonvascular plants and seedless vascular plants.
Section 7
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TEACHER: Let's take a look at three examples of nonvascular plants. Let's start with moss. Moss is by far the most common of all nonvascular plants. You're probably familiar with it. You've probably seen it on the sidewalk, on stairs, maybe even growing on buildings, even the statue that we saw of the lion.
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That's because moss is able to grow on a very thin layer of soil. Moss prefers to grow in shaded areas and moist areas, but it's also adapted to grow in all kinds of environments. In fact, my family and I were hiking not that long ago in the desert and we saw moss growing on the shaded side of some of the rocks. So some species can live in the desert.
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They can live even on the tundra or on the tops of mountains. And remember, even lava fields like we saw in Iceland. The next type that we'll look at is liverwort. Liverwort's a very simple plant. It has a leaf-like structure that grows as it folds over itself, a lot like a napkin when you're done with dinner. It just folds and overlaps as it grows.
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And it also has, especially this type, you can see these little depressions or little pockets where water collects, and microorganisms can be found in there. Finally, we have hornwort. Hornwort in the gametophyte stage looks a lot like liverwort. It has this flat leaf-like structure.
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And as the name suggests, in the sporophyte stage it has something that looks like horns. Like animal horns, not like the kind you would play as a musical instrument. At the top of these horns or these stalks are where the spores are produced. Now let's take a look at several types of seedless vascular plants.
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Here we have club moss. And you might be thinking, wait a minute. We just saw moss in the nonvascular. That's because the name club moss is quite misleading. It's not a true moss. In fact, it looks a lot more like little Christmas trees. It has vascular tissue and needle-like little growths and stalks, which at the top produce spores.
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Then we have horsetail. This is one of my favorites, because I grew up near a wetlands area where many of these horsetails grew. And as you can see, they have little joints. And if you break them right at the joint, they make a nice little [POP] popping sound. So they're really fun. I'm not recommending you do it.
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But as a child, a lot of fun to break at those little joints. And you can see that those stalks have leaf-like structures that grow out from the joints. Now the stalks themselves are made up of many hollow tubes, a lot like straws. And I've actually rubber banded together a bunch of straws. And I'm going to have my friend here hold this up so you can see how it looks if you were to look
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right into the horsetail stalk. So you can see all of the little hollow tubes. And what's interesting is that horsetail actually have the process of photosynthesis happening in the stalk, rather than in those leaf-like structures or leaves. Finally, we have a fern. And this is the most common of the seedless vascular plants.
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There are many, many species of ferns over 100. And some include lady fern, licorice fern, which my dad used to pluck off of trees. It grows off of trees in some woods, and if you tap it on your tongue, it actually tastes like licorice. Sword ferns, which of course, my brother and I had to pluck and pretend to have sword fights with.
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We thought we were so clever using sword ferns. And as you know, their leaves are called fronds. They have a nice fancy name. And their spores are usually found underneath in little brown clusters. So now you know three types of nonvascular plants and three types of seedless vascular plants. See if you can categorize them next.
Section 9
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TEACHER: You're now familiar with many different examples of seedless plants, and here you see one on pie. What are seedless plants doing on pie? Believe it or not, these are considered a delicacy. These are fiddlehead ferns. And if you haven't had your vegetables yet, you could sprinkle some fiddlehead ferns
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on your next meal. Here. I'll serve you up a piece of pie. Actually, not all ferns are edible. Some are poisonous, so don't go out and start picking ferns. Next, we're going to examine the importance of seedless plants and discover all of their uses, one of which is eating them.
Section 10
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TEACHER: Seedless plants are of great importance because they have many uses. Moss is a natural soil conditioner. That means that it helps prepare the soil for other plants to grow. Recall how moss can grow on a very thin layer of soil? Moss is often the very first plant
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able to live in areas that have been destroyed, like the lava flow that we saw at the beginning of the lesson or in the woods after there's been a forest fire. When moss dies, it rehabilitates the soil, building up a layer rich in nutrients that can support other plants. So it's good for rehabilitation. In fact, some gardeners use moss to enrich
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the soil in their gardens, so it's also used in gardens. There's another maybe even surprising use for moss. It surprised me the first time I learned about it. Here we see moss that was buried and compressed or pushed down, over many, many years with other plants in the mud in this bog, which is a wet, swampy area. The compressed plant material is called peat, and it gets cut like you can see
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and then harvested and dried. And when all the moisture has evaporated, the peat can be burned as a low-cost fuel. So let's put that right there. It says P-E-A-T, peat. Historically, peat was used to heat homes and used as an energy source to produce electricity. In fact, it's still used for fuel
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in some northern European countries. Many seedless plants have medicinal uses, and here we can see some moss that's about to be ground up in order to be used medicinally. Clubmoss was once used as medicine in order to stop bleeding. And some people have used ferns to help reduce fevers, heal bee stings, and even burns.
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Horsetails have been used to treat urinary tract infections and kidney problems and also to strengthen bones. Seedless plants are often used in shampoos and cosmetics. So there's something to think about the next time you're washing your hair. Moss and ferns are frequently used in floral arrangements, like we see here. Maybe you've even received or given
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someone flowers that had ferns in it, like there are in this bouquet. Can you identify the ferns? Here they are all around the border around the edges, all gorgeous ferns used to support all those flowers and make them really pop out. Maybe your family also use some of these plants to decorate your home.
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There are also something called clubmosses that look like small Christmas trees, and those are used often in greens during the holidays. And moss and ferns are also used in landscaping, so around homes and businesses.