How plants were formed, how plants were evolving. It is open. I usually don't block the door. It's open.
It's not cold. It's not cold. Yeah, I don't block the door.
They say it's locked in the outside. On the outside it's locked in. Try to go out.
I think you could like me. Okay, it was locked. I don't know, maybe there was somebody there.
Okay, it's not locked. So, like the general evolution, that means what kind of plants do we distinguish, what are the types of plants we see, and I need a whole derby, because there is a little bit about the real world. Still, I don't know. It's important to understand those types. And I need to know the reproduction, so we will mention those cycles again, and about seeds, and at the end we will finish with nice flowers, but that won't be the end.
So first part, you have heard about it. Remember endosymbiosis. What happened with mitochondria?
The mitochondria are not made by our cells, but they are dead bacteria, right? So this is important because that's the basic information about eukaryotic cells at all, meaning us. That explains why you have mitochondrial genes, which are kinda different than normal new PR genes. So that happened at the very beginning of eukaryotic cell evolution, and every.
Every eukaryotic cell we have found has at least genes from those mitochondria. So far, as far as I'm aware, we haven't found a eukaryotic cell which at some point of its history wouldn't have a cooperation with mitochondria. But after that, our pathways started dividing and some cells did this thing, some other cells did something different, and that's how plants started. So us, we stayed here, we just had one test, in hypochondria.
But some other eukaryotic cells started another endosymbiosis, and they got their plastids, which normally you call them chloroplasts, there are actually more than one type of plastids, but they all started from a bacterium. And, ah... Forget about mitochondria, because with mitochondria we know that there was only one, probably there was only one endosomal biases, meaning that there was only one event which every eukaryotic cell inherited after. With plastics, with chloroplasts, it's a different story.
They keep happening. Even now, they keep happening and there was many cases, but one of them probably was the first. So, that's why we call it primary endosymbiosis. But primary endosymbiosis doesn't mean the very first endosymbiosis which happened, because we know already mitochondria happened before.
But because mitochondria, like I say, it happened only once and for all, we don't talk about that. too much in case of evolution. In case of plant at least evolution, in case of chloroplasts, that is much more complicated because they kept happening and they still are happening.
So the first one, this is the one which finally led to quants. The guest was some kind of free cyanobacterium. Cyanobacteria, you saw them, In Bio2, those blueish-greenish things, so unicellular cyanobacterium, which knew already how to do photosynthesis, entered probably, it may be the way, it might have been a process of eating, and somehow...
it was not really finished and it stayed it could be a parasite that it could do photosynthesis it doesn't mean we wouldn't try to do the other stuff so we are not really sure what was the type of relationship they tried to do but they did and then cellulobacterium became the first chloroplast the chloroplast has two membranes just like cellulobacterium They have two membranes. It has their own DNA in the form of bacterial DNA, meaning it's circular and stuff. So we have a very primitive eukaryotic cell with a nucleus, endoplasmic reticulum, and chloroplast.
And then what happened, here they show you how the membranes, whatever happened with the membranes. We knew from bio tools that in some eukaryotic cells that didn't end with death. We know that those eukaryotic cells sometimes became their own chloroplasts.
So you have an eukaryotic cell which has a nucleus, which has the normal chloroplast, bacterial chloroplast, and the whole thing becomes another type of chloroplast. So when that happens, you have a new cardiogenic cell and a little biggish chloroplast which has, at least some of them have, a remaining... piece of nucleus that is called nucleomorph.
Sometimes it disappears completely and then we can have three or even more membrane chloroplasts up to five. The largest number I've seen was five. So we know that those weird chloroplasts happen by secondary endosymbiosis.
But that didn't happen in plants. So this is just to remind you that it happened. But in plants we have primary endosymbiosis.
And this is... only a tiny piece of eukaryotic cells, because I hope you remember there were those all kinds of diatoms, stromalopiles, stuff like that, right? So now we have only a big group which can be called plantain. And those plantain include green, aquatic, green and not only green, but also green organisms, green by definition, but still not green. not plants as we call them, and finally here land plants.
So how did it happen? We consider that the block of ice, and I will show block of ice a little later. But we consider them a sister group.
I will say that, but now I try to show you. You see that? This is a sister group of everything else. Not only plants, but everything else. The next separation were red algae.
We also mentioned them. They have, you can see them on the beach, they have very like reddish color, that's why red algae, they have different, I will mention them a little later. Finally we have green plants, and green plants includes land plants, but also some other stuff which live in water.
So I will try to show you a tiny bit about them. So as you see, whatever we used to call algae, and sometimes we still call them algae, it doesn't really exist. Because some of them are cyanobacteria, some of them are eukaryotes, but different. Some of them will belong to almost cousins of plants. And like, yeah, you see that, what I'm trying to say?
Algae was formed before we were able to understand relationship between those organisms. And this is like a little bit of a, like a... That drawer in your kitchen where you throw everything that doesn't match anywhere else and you don't know what to do with it but you don't want to throw it out and suddenly you have a bunch of trash in that drawer. I hope you understand what I'm trying to say.
Yeah. So, that's algae. So, the ancestor of plants, we don't really know how it exactly looked like.
because it doesn't exist anymore and we don't have much fossils. However, the sister group of everybody else are Glucophytes and Glucophytes, they actually changed on the way, but hopefully they show us a little bit how it could look right. So they are usually single cells, sometimes like here you can see the tiny groups of two or four maybe, some of these they are called colonies, they have very unusual plastids because those plastids didn't change as much as other plastids meaning chloroplasts and you can still find remains of peptidoglycan. Heptadonucleic acid, if you remember, I hope you do, is that one chemical compound which makes true bacteria very easy to find.
Because it happens only in bacteria. Not archaea, not eukarya, just bacteria. So why it happened to be there? Because these are bacteria that have even lost all of peptidoglycans, which normal chloroplasts in our plants, they just lost it completely and we have no remains of them. So, glaucofites, that's all I want to say about glaucofites.
Now we will mention a tiny bit about red algae, because we didn't really talk about them too much in Bio 2. So, a tiny bit about red algae. Have you seen it? Probably you have, right?
Usually we complain that, ah, that's much of junk there. So, a lot of them will belong to red algae. They live only in water. salt water specifically they don't really happen in freshwater they have weird weird pigments associated with their photosynthesis like phycoerythrin Erythrin sounds like erythrocytes can you feel the connection that phycoerythrin erythrocytes erythrocytes meaning red blood cells are red so you can easily remember that that is the red pigment they have The name didn't come up by accident.
It's actually because it gives them the red color. And chlorophyll-A, which is typical for the primary endosymbiosis. Are they also red?
The second one, the chlorophyll? The chlorophyll-A? They're both red or only one is red?
No, chlorophyll-A is the normal green. It's like fresh green color. Oh, okay.
Yeah, that will happen also chlorophyll, it will happen also everywhere else, like plants. Additionally, they will have different chlorophyll, but yeah, so that one is green, but you don't really see green because that red covers it kind of. Okay. And marine, blah, blah.
A... Oh! Fico Airetrain works for them really well because it absorbs different wavelength, so they can grow actually very deep.
Where normal green algae they cannot already because the... light they respond which is mostly rare, that it doesn't really get the tip. That additional pigment makes it possible for them to survive because it's enough light which they can use so they can actually do photosynthesis in deep waters.
So other algae. Now we move, we skipped the, we did the brown covites, we did red algae, now we move to green algae. And green algae, it's another trash bag. Meaning we threw stuff here. We know already they are not a claim per se, because they...
include two not closely related groups. And we don't really know what was happening here, so one group is called chlorophytes, and surprise, surprise, plants don't belong there. And the other group is called streptophytes. And that's where plants technically should belong. It depends, in old books they say streptophytes and plants like separately, like out of nowhere, but now we know that they don't belong to streptophytes, they are closely related to them.
They are all green. They have chlorophyll A and B. All of them.
But the differences between them are very deep. Like, how do their cells divide? That's a hard word, and I don't require you to remember, but you see that phycoplast and phragmoplast, it's the way they do cytokinesis. Remember mitosis?
It's just a nucleus, right? After mitosis, we need to divide the whole cell. And they do it in a completely different way.
So I can imagine that that difference is really old. Because after you have a big plan, you cannot suddenly decide, now I'm going to change my cytokinesis. Everything will fall apart. You will simply die. So that change is probably extremely old.
Okay, I will show you a few examples, but don't worry about those too much. This is just to show you diversity. So, this one, this one will happen, this one will happen. So you see, they are just examples.
Ola! You can actually see very frequently, it's a very common algae. It is called like a sea lettuce or water lettuce. And yeah, probably because a lot of animals like much on it.
So this is a chlorophyte. And I didn't mark it because I thought that it would show up right away. And the other two, these are, they belong to streptophytes.
I mean, hard to see. If I look at them, all I see is a green algae. But once they started checking out the... their genes, that's when everything showed up.
That yeah, they are not really that closely related as we used to think. Other green algae, these are, I mean that one you should see, Senodesmus, Bulbux, we saw them, at least I'm not sure really. So I'm not gonna say anything about them. There's a lot of them really.
Okay, so what we did, chlorophytes, meaning the ova, streptophytes, spirogyra, you saw it too, then we saw that one, the flat one, it looks like a little pancake on a screen, and stone words, do I have one? It looks like a horse tail but lives in the water. If you see something which looks like a horse tail and it lives in the water, that would be dead.
So it's not even a full blown plant. And finally we have land plants. And what happened when we got to land plants?
And then it's even more. So now the whole lineage which got here, we see what do we have in here. And please don't try to write it down in panic. The whole lecture we will be going along this piece.
So we don't have to now write it down. Let's think what happened here. The major change which happened was that plants started protecting the zygote.
Since then we can talk about an embryo. Because what makes an embryo an embryo is that you kind of try to protect somehow that new developing organism. So...
You can hear different names for land plants. Embryophytes. That's the same, basically.
Because they do protect their babies. At least a little bit. We have a bunch of major, they say ten, I haven't really counted, major clades of land plants. Those clades, I mean probably there is ten, those clades, I hope you remember what are clades, what are clades? These are those taxa which have one common ancestor and include everybody and only descendants of the common ancestor.
Meaning nobody else. was attached to that taxon and nobody stayed behind nobody was excluded so like reptiles not not a play because we exclude birds but here are plates actually so somebody really tried to clean it out so those plates are grouped into three major groups which are non-vascular plants we solve them a little bit right so liver works muscles I will show you a little more about the other two. We have vascular and inedible seedless plants.
Normally we say vascular plants, but actually if you look at them, they are all vascular plants. All are vascular plants. So I don't feel it makes sense to say that these are vascular plants and these are something different because they are still vascular plants.
So to make it kind of clear and precise, I tend to say vascular seedless plants. Then it makes sense because these are those except for the seed plants. And finally we have seed plants which include gymnosperm and angiosperms.
We will mention them kindly now. I mean, not now. Okay, so don't panic. We will go slowly.
First, what really happened on the way? Watch out, these are not synapomorphies. Synapomorphies will happen a little later. So what really happened during their evolution?
The major synapomorphy, which is included here, it didn't happen in the liver world, so they stayed behind. But it's still important and it allowed plants to actually colonize the land fully. Stomata.
Somebody asked me what are they, so here you go. This is a picture like how you look on the epidermis of a leaf, let's say. So you look at the leaf and you magnify the truth really, really a lot.
These are epidermal cells, meaning their skin. And some of them change. are very specialized and that's a cell, that's a cell. They do look like lips, but they're sideways. And they work like lips because they can open and close.
And when they open, plants can do gas exchange, but also they can, they will do. water which losing water somehow is what plants tend to do because that's how they transport water they need to transpire water to transport water but losing too much will make them die so it's a great discover which they did, that they can regulate it, and when they start to become too dry, they lost too much water, they can close stomata. But then they will suffocate, because they cannot do gas exchange. So it's a little bit of a hard choice sometimes, what we do to survive, but it's a great thing. The next thing, which happened much later, here, so we are skipping lycophytes, but to ensure everybody else are mega.
meaning making big leaves basically. And I will show the big leaves on a separate slide so I don't want to talk about it too much now. But big leaves.
And the final one, seeds and flowers. Okay, so here, this is what you have in your book. You have no vascular flights, meaning liverworts, hornworts, mosses, you don't have to worry about the scientific names for them too much.
You may try to memorize bryophytes, however, I usually try to say mosses, not to make it too difficult. Then vascular plants, and pay attention, they eat bright because they need vascular plants and seed plants like a sub-category of vascular plants. So I kind of like it. Which are lycopods and mononotiles, which includes everything with big leaves, and seed plants.
So we will talk mostly about examples of them and I want you to focus when you are learning on bryophytes, on monilophytes, and on coniferophytes and angiosperms. I mean gymnosperms and angiosperms. Not fully gymnosperms. Coniferous and angiosperms.
Okay, that is a question. Okay, so what happened in their evolution, in plants'evolution, which allowed them to really colonize land really well? Synacomorphies. Meaning you cannot mark everything which plants have, because plants will have a lot of things, but what changed comparing to their ancestors? Some new stuff, which was very important to colonize land.
First, not plants that... about 450 to 50 million years ago, very long time ago. What they need to do, they needed to do few things. First, I mean, protect your body from losing water.
So they had to adapt to dry conditions and that included a lot of things, cuticle. Remember cutting out cuticles, that's kind of the same thing. It's a layer of wax, literally, which protects their skin from drying out.
But once you do cuticle, you cannot do gas exchange through the epidermis. So that's why they needed stomata. We know about our stomata. Then, they needed to transport water somehow because, I mean, you cannot do really well if you are very flat.
So they at some point created mechanical tissues, supportive tissues, which allowed them to grow high, and then transport water. And finally they had to find a way to disperse their gummies and altogether how to reproduce. And that is a huge thing, meaning they had to do the thing with their gametophytes and they had to protect their embryos, finally at some point with a seed.
So they had to do all kinds of stuff. But I hope you got it. Cunicles, stomata, embryos, that would be probably what you want.
It's called my chloroplast because everybody had it before, right? So that's not a synapomorphic. Synapomorphic has to be something new. Can you move it? Yeah, I can.
Can you move it? Yep. You said stomata, cuticle, and what else?
What do we have? Which ones do you mark? Yeah, which ones do you say mark again?
What are the options? It's mitosis, chloroplast, stomata, cuticle, and vascular tissue. Okay, think about it. What about mitosis? Yes or no?
Who says no? Say proudly. Myosis wouldn't be part, right?
Because myosis happened much, much earlier. That's not a synapomorphy, it's not new. Cuticle, we know that yes.
Stomata, we know that yes. What about vascular tissues? So what is it, yes or no?
Yes. Why? Yes.
I wrote it down so I put yes. Yes, you are correct. This is the system which transports water. Vascular tissues, water transport. So that's what you need to connect.
The vascular tissues, these are the ones which transport water. And nutrients the other way. But still. And what was the last option? Chloroplasts.
Yes or no? No. Correct.
Okay. Everybody had it already, right? Not as an apology.
Can help them, but it's not anything new. Okay, we just saw that. I think that's pretty easy. So I'm gonna skip the tight gummies. Remember that gummies, to make them work, they cannot be dry resistant.
It means that you cannot just spread your gummies all over around you when you live in the land, like plants and animals would do when they were living in the water. So that's the trouble. That's why they chose alternation. generations. And that's the alternative, meaning pollen, that's a spore and the whole individual which will make gametes lives inside it.
So how did it start? Water algae, all those algae, it doesn't matter where they belong, they have green algae, not only green algae, they have few different options for their lifestyle. And we belong there too. So actually that applies to every eukaryotic cell.
So we have three options. We can be mainly haploid. Lycans, or diatoms I believe they do that, if I remember correctly. So they live their life as haploid organisms. And at some point they decide, okay, let's reproduce.
They become, because they are haploid already, so they just change into gummies. And they will become one of the type of gummies. Very often they don't really have sperm and egg.
Very often they have isogummy in that case, but they work just the same, so it doesn't matter. In case of multicellular algae, they will make those sperms and eggs, then they will fertilize. We have a zygote, but they don't live as a diploid organism.
Right away, that zygote will go through meiosis. It will reduce their chromosomes to just one cell. So we have four cells haploid, and each of them will start their own life. So basically their time they spend as deployed is just one cell That's not us, right? It's very weird for us The other cap...
So this is called, let's go back for a second, this is called haploid or haplontic life cycle. If you tell me haploid life cycle, I will know what it is. Then the second one is diploid or diplontic life cycle.
So that's the other story. You spend your life as a deployed organism. And that's the point you decide, now I want to reproduce. So what you do, you will do meiosis.
And after meiosis you have gametes. Those gametes, they will right away, they don't divide anymore. They are just there, even if they wait a little bit, they are just there waiting. They do fertilization. we have a zygote and that zygote, diploid again, will start growing.
If it's a multicellular organism, they will do repetitive mitosis and stuff like that. So diploid is the blue one and then when you do meiosis it becomes the second word? Haploid. haploid, diploid, haploid, diploid, haploid, yes exactly, guess what?
That's us, right? That's what we do, that's exactly what we do, so what I say here, it doesn't apply just to plants or algae, it applies basically to everybody, every organism. which is doing meiosis, which is able to do meiosis, bacteria won't fit in, because bacteria they don't do it. But every eukaryotic cell which can do meiosis will do one of those things.
One, two, there is the third option, the hardest. Some algae, aquatic algae, they they found a different way. So let's start from being a zygote.
You have your zygote, you will grow Via mitosis. You will grow into a big organism and at some point you will decide I'm gonna do stuff. So you will do meiosis and you will produce haploid cells but they are not gametes. Because gametes, what is important with gametes are those cells which will do fertilization. And they don't.
so they are not damaged if they don't fertilize instead of fertilization they will start growing on their own so that's why we call them spores if they are water spores they may not have that very big thick wall but very often algae do that and actually they make equal because it helps them survive winter or drought So many algae are doing that even when they don't really try to colonize land at the moment, but it still helps them to survive. So spores are really cool for them. But when time is nice, those spores start growing. They don't do fertilization. They start growing and make another individual.
This is Hatoi. And that haploid at some point will delegate some of its cells to become gummies. And gummies will do fertilization and the zygote and the zygote closes.
An example is uva. We mentioned uva. both generations of ULPA look really similar. If you look at it, maybe somebody can tell the difference, I cannot. I think it's called isomorphic life cycle, meaning they look...
very much the same. In some cases their generations won't look the same, they will look different and it's still fine as long as there is at least one cell division between this and this you have two generations. So this is called diplo-haplontic. Diploi, diplontic, haplontic. Remember this is a combination of both.
Diplo-haplontic life cycle. And that's how plants started. That's why I wanted to show you three options so you will see how plants fit into the pattern. So yeah, so that's how plants started. Why?
Because those probably were the only ones which were able to survive drought in the long term. Because they were still able to survive drought and reproduce in that dry environment. So that's where plants fit in. Okay, one more time and that question will keep happening. What happens between, I don't know, before gumming production or what happens after biosis?
What kind of cells will be formed by a biosis? So, we have sporophyte, which is an organism. When I say organism...
I need more than one cell. Sporophyte. Then, meiosis will happen. After meiosis, we have spores.
Spores. Spores will grow into another organ. which is called gametophyte.
That gametophyte will do gametes, but it cannot do meiosis anymore. It's already half-dried. You cannot do a meiosis if you are half-dried. You cannot do those tetraids and stuff.
So it has to be mitosis. So you have gametes, fertilization, you have a zygote, and that zygote will start growing again. Okay? So here, I pointed out, I hope everybody will be able to understand that question will be happening. I mean it's a cycle so you can start at any point and you will work your way around.
It's usually easier if you choose that kind of the cycle which is easy for you to identify. Usually fertilization or meiosis are catching our eye more because it's like you see those cells connecting, right? So try to choose any point which you can identify and then work your way.
If you start from sporophyte, you have to work your way back to sporophyte. But you can as well start from gametophyte, right? And you can work your way back to gametophyte. Okay, so now I can start doing a tiny bit of diversity of plants.
And we will try to say a little bit about the reproduction, but also see them a little bit. So we have... First, liverworts, muscles, heartworts, these are non-vascular plants. And I don't know why I'm asking about muscles.
I show all of them. I should put that arrow a little differently. Look what happened.
Stomach happened. In this lineage, liverworts, they don't have it. See that?
Then, we know that all of them have a dominant gametopoietic. I hope you know already. All of the three. But... This is a little weird with horn words that they're sporified even though it's dependent, it's green.
So it looks a little bit like a little transition moment between that option and that option. So you can remember those hormones as kind of weird a little bit. I will show you how they look. So these are liverworts. And if you ever saw chicken liver, not cooked, they have like flaps, right?
So somebody thought that they kind of look like liver. I mean, that's a very vague comparison, but that's how the name came up. Liverworts meaning flap.
They give in. in streams close to them. So they don't live really like, they are not aquatic plants per se, they are not South Irish, they can survive, but they don't try to.
But they cannot live in the desert. So they are like stone birds? Yeah, yeah, yeah, they will grow on those rocks, marble, yeah, close to the street.
So you can very often find them there. And they can look kind of cool, they are very tiny and softish. Then these are normal mosses.
What you see here, this is the gametophyte and those green hairy looking structures, these are sporophytes, brown stuff, and they will burn spores. And finally hornworms, horn because their sporophyte is very... elongated.
So these are four words and you can see the sporophyte here, which actually I can see that it's green. So it's not independent because it's not green enough, but still. Okay.
Let's look at mosses a little closer, because those liverworts and hardworts, we are like, just to show you some diversity, mosses we need to understand a tiny bit more. We know they have stomata, we know their soil is not green, we know it from the phylogenesis of them. But what do they really look like? It's one non-branched stem with tiny, very soft intaglio. because they don't really have true tissues.
The island knows the ronka man not in hard there. So they are nice in touch. At the top they have their gonads, meaning their gametanche.
They are called archi gonads. I will show them in a second. And when fertilization happens, sporophyte stays here and grows.
So you have embryo growing here on the mother's body. This is sporophyte. That little bulge here is sporangium, which will make spores via meiosis, we know already.
And when they are ready, they have very often a tiny little opening here, which opens and spreads those spores. Okay, let's go. Their life cycle.
Important and you will be asked many times. Which plants have their gametophytes as their dominant? face, muscles, you need to know muscles, right?
What can you say about muscles? That their gametophytes are dominant because this is the only face. I mean, not only muscles, different words and hormones, you know, too.
But, like I said, I want you to remember that these muscles. So how do they look like? This is gametophyte.
And here that little thing will, after fertilization, start growing into the sporophyte, which is short-lived and dependent. We talked about it, let's make sure that we got it. Let's start from a score, let's say.
You see, I can start at any moment. We have a score. Usually it's easier to start from a single cell, from some event you understand. However, I don't know, you can start this one here. So as far as haploid, it germinates, meaning it starts growing and doing those mitoses.
That is called protonema, which if you forget, I'll find it there. And that protonema, it's making like a little growing thread, and once in a while starts growing into a moss body. That is a moss. It's still haploid.
On the very top you have antheridia and archegonia. Antheridia will make sperm. They cannot do meiosis because everything is haploid. So they will just become sperm. And this is archegonia.
with an egg. They are tiny, mosses are tiny. They live in humid and watery places.
A lot of rain. So when rain happens, water transports sperm from anteridium to archegonium. Fertilization happened, we have a zygote. Do we need the answer?
Should I go back to something? No, I was just asking for one. Yes. And the zygote... grows.
Remember what we said that land plants, they protect their embryos. That's their protection here. You see? The zygote doesn't need to handle their own life right away. It is a little bit protected and fed by their mama.
And then the zygote grows into that little brownish stalk with scorangium on top of it. Everything here, the brown stuff is deployed. So then inside scorangium, we have those Sporocytes, mother cells of spores.
Those cells will go through meiosis, will reduce the number of chromosomes, and will make spores, finally. Okay, I think you got it. This is the same, exactly the same.
I just wanted to show you how it really looks like. We will be looking at that at some point. So, Archegonia, with a nice big egg. And antheridia, antheridia are, they look different, they look kind of like sacks with stuff inside because they usually, while Arthegonia usually make one big egg, antheridia make plenty of tiny little sperms. And, okay.
So we are moving to actual vascular plans and I'm using every moment I have because there is a lot to say. So we will wait for a moment. Vascular plans, right? Why vascular tissues are so important? Because without them there would be only mosses.
And that's it. Not much diversity. Vascular tissues really help plants to really explore the land.
So we have two vascular tissues. We have xylem which transports water up and phloem which takes nutrients down to the root system. So we have those vessels moving water and we have phloem pipes moving sugars.
Xylem, phloem. Another important xenagomorph in which sometimes it's underestimated was the ability to make lignin. Lignin is a chemical compound, really complex.
That's how it looks like. That's lignin. You don't need to worry about its chemical structure, nobody will ever ask you about that, unless you are doing some very specialized PhD probably. But it's important because once it happens in cell walls, those cell walls become, first, very hard, and second, they won't let water flow, so that you have also to protect from water loss.
So, late lean was great, and that was a big kick-off for plant evolution. And after plants learn how to do licking and muscular tissues, they will send a whole story back. So that's what we will do on Monday. We had invasion of the land about 40 kilometers ago by those muscular tissues. Thank you.