Seed Plants

Hi. In this video, we're going to talk about seed plants now. Seed plants are made up of angiosperms and give no sperms. And remember that there a mine affiliated group meaning that the seed just evolved once and split off towards angiosperms in one direction and give no sperms in the other. Like all vascular plants, they have a spore fight, dominant life cycle. But unlike the seedless vascular plants, most of their Gumede a fights are actually microscopic, so they're even mawr diminished and thes, actually convivial up within the spare angina. Now most seed plants are hetero forests and contain micros baranja that produce pollen and mega sprang JIA that are found inside a Buell's. And we'll talk about what a buell's are in just a second Now. It's also important to note that most of these plants will have the micro spare angina, which is the male part, right and mega sphere Anja, the female structure on the same plant. However, some will be found on different plants. Now you can see here we have two types of cones. These are you know the technical term is Strobel, I and here we have the mail. One that is going to house Micros Baranja. And here we have the female version that is going thio. How's the Mega Spear? And yet, so the op You'll is the structure that contains the mega sphere Angie, um, and the mega sport, and it's actually what's going to develop into a seed after fertilization. Uh, the outer protective layer of the oval is known as the Integra Mint, and it's made of spore fight tissue, and you can see that game. No sperms have this singular Integra mint, whereas angiosperms have multiple Integra mints. Don't worry so much about memorizing all the facts about giving a sperms and angiosperms. Right now. We'll be going into much more detail in, uh, about plants in other chapters. So the opening at the apex of the Integra Mint was called the Micro Pile. You can see them here in these obstacles, and this outer wall in the angio sperm is the ovary wall. So the angiosperms are gonna actually have this ovary that is going to cover the AV you'll, and that's actually what develops into fruit. So basically, when you're eating fruit, you're eating plant ovaries, and they're delicious. Now, pollen grains are the mailed me to fight, covered by pollen wall right, which is a maid of spore pollen in, and it's a tough struck, a tough coating. It's gonna help protect the interior, and these are produced by the micro spores. The pollen grains are produced by the micro sports, and when the pollen travels to the A visual we have pollination and pollination syndrome is a term that refers to flower traits that have evolved in response to pollen vectors like wind bees and birds. So, in essence, pollination syndrome is sort of a group of traits that have evolved specifically to, um or specifically in response thio certain pollination vectors. And there are tons of pollination vectors, many more than I've listed here now, seeds which we can see right here these air seeds. Or this is a seed. These air a fuels seeds develop from fertilized Aviles. Right, So this is going to turn into Well, this, I should say, is going to turn into that, and they contain the embryonic plant, which you can see right here. I'm gonna jump out of the image so it's easier to see the embryonic plant, which is this structure right here. And they also have this protective seed coat which allows seeds to stay dormant but alive or quite some time now, the Kotil a dons are these little embryonic leaves contained in the seed and they will germinate toe form sprout conceived. They've been, uh, labeled here, but our flotilla dons are actually thes structures right here. I don't know what these errors air pointing off to. So me redraw those cattle Adan Ayro, These are the flotilla dons now the end of sperm is basically the food for the embryonic plant. And it's all the stuff surrounding the embryo. Eso if you eat a seed, mostly what you're eating is endo sperm. If you've ever broken a peanut in half and noticed the little notch on the end of it, that is the embryonic plant. And the majority of the nut is the end of sperm. All right with that, let's flip the page

give no sperms produced naked seeds. Basically, that just means that they're not enclosed by an ovary like angiosperms. The speranza of game No sperms are usually packed into cones and as we were talking about earlier, generally most plants will have the male and female spring, and you write the male cone and the female cone on the same plant. We call these money cious plants. Some plants, however, are diocese, and you'll actually find the male and female sprang JIA on different plants. So those male and female cones will be found on different plants. They won't be found on the same individual. A Conifers are probably the given of sperms. You're most familiar with these pine trees, and they're basically the group of given of sperms that have those distinctive needle like leaves. Write what you know we think of is just pine needles. I mean, there's many different types, but that's ah feature that defines the Conifers, and also there sprang JIA are contained in those cones which are technically called Strobel. I now the cones air actually modified leaves right there, Spore fell, and the pine needles represent a new evolutionary modification of the leaf that has a very thick cuticle. And this helps thes plants prevent water loss because, um, you know, Conifers e mean, they're Conifers all over the place, but they can live in areas that have, um, you know, restricted access toe water. So these pine needles allowed, and especially in the wintertime, they live in cold places where it could be very hard for the roots to obtain water due to frost and freezing temperatures. So these pine needles are evolutionary trait that allows them to really prevent water loss very effectively. Now, let's take a look at the life cycle of a game. No sperm. When the pollen grain reaches the AV, you'll it's actually gonna germinate and form what's called a pollen tube that digests its way through the mega sphere. Angie, um, so here we have our pollen grain, it's gonna get to our Uh huh. It's gonna get to the fuel. And then here you can see the pollen tube digesting its way through the av you'll to the mega so brandy. And now the mega sports site is going to undergo bios icis and produce four half Lloyd sells, one of which will become the mega spore and the mega spore will actually develop into a female comedian fight containing multiple eggs. When the pollen tube reaches the exits going to eject sperm that will fertilize the egg and then the a visual will become a seed. And after fertilization, of course, we're gonna have formation of the embryo. And that is our a little seed right here. It's resting on one of the scales of the cone. So if you look at a pine cone, it has all these little scales thes little. They're like little diamond shaped things in the figure, but their little cone scales. Well, if you were to peel that back and look at it, that's where the seed develops, right? That's where your seat is gonna be Now. The seed, of course, will, um, get carried away and sprout into a spore fight. And that is what grows into, you know, the's big, hulking trees that, of course, will develop their male and female cones and repeat the cycle over again. Don't worry too much about memorizing all the aspects of life cycle GMO sperms. We're gonna cover that much more detail when we take a deeper look at plants. This is just a meant to be sort of a broad strokes overview. Alright, with that, let's flip the page and talk about angiosperms.

angiosperms are perhaps best known for their beautiful flowers, and they're delicious fruit which surrounds their seeds. They're actually also the most diverse group of seed producing land plants and angiosperms are generally classified based on how many cotillions their seeds have. Monica cots have one cattle Adan and you die. Cots have to cotillions. You can see Amman a cot over here and notice how it just has these one leafy bit to it. And over here we have a you die Kat. Notice how it has to leafy bits on its sprout. And, yes, leafy bit is the technical term there. Now you might be wondering why it's you die, Kat. You meaning true and not just die Kat. The reason is the group actually used to be called die cots and included other species that have since been rearranged into other lineages. And those other major lineages are basil angiosperms and magna leads. Now let's take a look at the flower. The defining feature of the angiosperms. The flower is theory reproductive organ of angiosperms, and it has a many parts to its anatomy. You've probably taken note of these if you've looked at flowers before, but you may not have known all the terms for each of the parts. So to begin there's the sequel, which, if you've ever seen a flower bud, it's that those green leaves that, um in case the little flower bud. And when the flower bud matures, they look like those green leafy, leafy bits underneath the pedal. So right here, this part is a siebel. Now we also have the pedals. Obviously, these are modified leaves that surround the reproductive organs of the flower. And their purpose is often to attract pollinators, which is why they have thes beautiful colors and sometimes interesting patterns inside of them. The stamen is like the male part of the flower. This is the pollen producing part, and it's made up of the filament and the anther. And you can see a stamen right here. This is the filament where the stock there's also one marked over here. This it's our filament. And here we have the anther right that nub on the end. And if you've ever had fresh flowers, um, hang around your house for a little too long before all of the stamen fall off the answers knock pollen everywhere and It's like a huge mess. Trick is you gotta pull them out before the flowers die. Now, the carpal is like the female part of the plant, and some plants actually have multiple carpools. And if a plant has multiple carp ALS, they are referred to collectively as a pistol. Now, the card bull is also made up of different parts. And you can see we have the carpal right here and the top of the carpool, which let me use a different color. The top of the carpal is referred to as the stigma. The portion that goes from the stigma down to the ovary is called the style you can see style is this portion here The ovary is this lower portion that contains the av you ALS, which will become the seeds in the fruit. Now, over here we have another Ah, another ovary. Or I guess they're showing the stigma as well. So I guess technically, this is a carpool. Full carpool, though the top of this image is a little cut off. So that's why it looks a little funny. But anyways, within, uh, within the OB, you'll hear is our embryo sac. It's basically the female gamete a fight inside the fuel. You can see here a pollen tube is extending to it. And of course, fruit is formed from the ovary. Right, This portion, the ovary of the carpal. All right with that, let's turn the page.

Hello, everyone. In our last lesson, we talked about the anatomical structures of flowers. Now we're going to talk about the different types of flowers that you confined on different types of angiosperms. Okay, so we previously talked about things like Cibeles pedals and thirst, filaments and things like that, right? The structures did you find within a flower? But those structures can vary depending on which type of flower you have. So there are complete flowers in complete flowers. Perfect flowers. Manu wishes flowers and die Alicia's flowers. So what we learned about previously what we saw previously were complete flowers. They contain Cipel's pedals, stamen and pistols. So see pols and pedals and remember that stamen includes the anther and the filament. And these were going to be the male structures that create pollen and create sperm. And then pistols include the stigma, style and ovaries, which are going to be the female components of the flower, which create the egg and will eventually create the seed or the fruit. Now, if it is missing, if the flowers missing any of those four structures, it is considered an incomplete flower. If it's missing any of those structures otherwise, it is a complete flower. Some examples of complete flowers are gonna be hibiscus flowers. Roses are complete flowers. P plants have complete flowers, and I believe two lips are also complete flowers as well. There's many more examples, but those were just a couple. OK, so now let's talk about the perfect flower. You may think that the perfect flower in the complete flower probably the same thing. That's actually not true. They have kind of confusing names. You would think a complete flower would be a perfect flower, but in fact it's not a perfect flower is going to be a flower that is bisexual. What that means is that it has male and female structures in the same flower, so that means it has a stamen and pistols. So this is stamen plus pistol. Now you may be thinking, Oh, well, then it's probably a complete flower. No, because it doesn't have to have seat bowls, and it doesn't have to have pedals, and it could still be qualified as a perfect flower, long as it's got a statement and a pistol so perfect flowers can be complete flowers, but complete flowers or not always perfect flowers so Manu Wishes and Dia wishes are gonna be two other types of flowers. So mono, Aetius and Die Alicia's. You've heard those terms used before. Generally, when you're talking about animals and the sexes of animals, so mono Aetius plants or mono Aetius angiosperms are going to have unis sexual flowers. That means that means that the entire flower is either male or female, either on Lee has answers or on Lee has pistols, but the's male and female flowers are found on the same plant. So what that's going to look like is if we have a mono Aetius species of angiosperms, what we're going to have is, let's say we have these two. Bush is here and there, the same species of angiosperms. We're going to have male flowers, and we're going to have female flowers in red, so male flowers and blue female flowers in red. So if we have these two individuals of the same species, they're going to have male and female flowers on the same plant. So both of these plants will have blue and red flowers. They will have both sexes of flowers on the same plant. This is Manu Aetius and generally, when we talk about Manu wishes organisms. We're talking about hermaphroditic organisms, organisms that possess both qualities of both sexes. And these angiosperms do fit that category. Now Die Alicia's Flowers or Die. Alicia's angiosperms also have unis sexual flowers, meaning that they have male Onley flowers and female Onley flowers. However, these air found on completely different plants. So what is that going to look like? Di Alicia's is going to look different because now, if we have the same two plants, but this species is delicious, we're going to have one male plant and one female plant. So let's say that this is the female plant with the red flowers and then one male plant with the male flowers that is a Daio Isha species of angiosperms. And that's because Daio Aetius is generally referring to to different sexes. Human beings air die Alicia's. There are individuals that air solely male, and there are individuals that air solely female. The same thing is happening with these particular plants. They have male flowers that are on Lee found on the male plant and female flowers that are only found on the female plant. These air die Alicia species so there are different types of flowers on different types of angiosperms. So some examples of mono Aetius plants would be things like squash and corn have both male and female flowers on the same plant. Some examples of Daio Aetius plants or die Alicia's angiosperms would be things like willow trees. If you've ever seen a weeping willow, it's dyou, Aetius, Holly uh, sassafras. And also poison ivy is an example of a die Alicia species. There's male and female plants. There are many other plants. Those were just some examples of the two different categories. Okay, so now since we talked about flowers, let's talk about the different forms of pollination that you can have dealing with those flowers. So first we're going to talk about cross pollination. Cross pollination is where pollen is transferred from one plant in the species to a completely different plant in the species. So basically one individual is fertilizing a different individual. Now this is going to be what is preferred in the reproduction off angio sperm plants, and that is going to be because this allows for genetic diversity. It is sexual reproduction. This is how to separate. Individuals are going to mix their genetics to create a zygote and eventually a seed or a fruit, which will create the new plant. Now this is in contrast to self pollination. If an organism or an angio sperm self pollinates, it is able to take pollen from its own anther and fertilized its own egg in the ovary. So that is self pollination. This is not particularly preferred because this is basically cloning yourself. You're basically not making any new, Um, you're not making any new genetic diversity here. Cross pollination is preferred, but some plants also can perform self pollination, if maybe if they need to reproduce. But cross pollination makes genetic diversity, and that is what they're looking for. Okay, so now let's talk about double fertilization. In fact, angiosperms do this really unique process called double fertilization. Usually, when you think about fertilization, you think of the sperm fertilizing egg to create as I go. That's single fertilization, and that's how a lot of reproduction happens. Angiosperms, however, do double fertilization. This is where a sperm fertilizes the egg to create a zygote, and another sperm is utilized to fertilize what's called the polar nuclei, which you're gonna become the Indo sperm. So let's go down and let's look at a diagram of this. So this here is going to be a diagram of the overall angio sperm life cycle. I'm going to go out of the picture so you guys can see the rest of this. So let's start on this side here. We see that the answer is creating the sperm and is creating the pollen grain. You can see the pollen grain right here, and the pollen grain is then going to be, um, used for the process of pollination, either by wind or by pollinators like birds, bees and butterflies. And the pollen is then going to be transferred to the top off the stigma on the, um on the female aspect of the plant. So then the pollen grain attach is to the female aspect of the plant, and it begins to create this pollen tube, and the pollen tube travels down into the ovary to fertilize an egg. Once it has reached an egg, then the sperm, which you can see right here thes air the sperm, the sperm are going to travel down the tube and they are going to fertilize the egg and they're also going to fertilize the polar nuclei. You can see that process happening right here. The egg is going to be fertilized. That's the first round of fertilization. And the second round of fertilization is where the polar nuclei cells are going to be fertilized. Now what's the point off the polar nuclear nuclei sells? Those are going to create the Indo sperm and you can see the Indo sperm right here. So we have the embryo and the Indo sperm. The results of the two fertilizations. The embryo obviously will become the new baby plant, and the Indo sperm is going to be the nutritional substance inside of the seed that is going to allow the baby plant to grow. You can kind of think of it like the yoke of an egg. It is there for nutritional purposes and it is going to give the embryo fats and oils and anything that it needs to continue to grow and to get out of the shell of that seed to create a seedling. So the Indo sperm is going to be the nutrition, and this is going to be the process of double fertilization, one fertilization is used to create the embryo and the other fertilization is utilized to create the Indo sperm, the nutrition for the embryo. And this is going to be a characteristic that is very unique to angiosperms. Okay, everyone, let's go on to our next topic.