Land Plants - 4

by Jason Amores Sumpter
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non vascular plants and most seedless vascular plants are homeless porous, which means that they only produce one type of sport. Now, some seedless vascular plants and all the seed plants are hetero sports, meaning that they produced two distinct types of spores. And those two distinct types are micro spores, which are made from micros baranja, and these developed into male Gumede A fights, so these will ultimately lead to production of sperm. And then you have Mega Spa Ranjha, which produce mega spores. And those mega spores will develop into female Janita fights or eggs. Now, in terms of reproduction, uh, non vascular plants and seedless vascular plants have a big disadvantage compared thio uh, you know, later plants, and that is that they their sperm requires water in order to get to the egg. Not only does it require water basically requires a continuous path of water to get to the egg, so essentially this means that those organisms can Onley produce when it's wet out, and this kind of restricts them to environments where there's enough moisture. The adaptation of pollen, which is the male gimme to fight, surrounded by a spore, a pollen and coating Basically, this is like a tough coating allows for, uh, the male comida fights. And ultimately, the sperm thio exist without water for a much longer period of time. They can be exposed to the air for a long time, and furthermore, they can actually take advantage of the air as a medium through which to travel to the egg. So pollen was a huge important adaptation, and it essentially allows thes sperm to travel through the air to the egg and not require water. Thio actually fertilize the egg, and we'll talk about the specifics of that later when we talk about seed plants now, the seed itself, as I said, was a big evolutionary adaptation, and seed is basically just the embryonic plant, right. The embryo of the plant and a food supply on this is all surrounded by a tough coating that allows the seed thio resist environmental damage and degradation from being digested by a non organism, for example, and seeds form from fertilization by pollen. You can see, uh, pollen here. All these little yellow dots are bits of pollen here. We actually have, uh, an electron microscope image of pollen. You can see that There's, Ah lot of diversity in, uh, you know, uh, inform. There's a lot of pollen can take a lot of different shapes and here we actually are looking at the inside of a seats. This is a seed cut in half and let me jump out of the image here. This is our embryonic plant. It's a dichotomy. You'll learn. Why later? Don't worry about it now, but if you know why it's die Kat thumbs up, it's because it has these two things again. We'll talk about this later, so don't worry if you don't know what I'm talking about right just yet. So this is our embryonic plant, and this is what's called Endo sperm. And basically it's the food supply. It's the food supply for the embryo. The embryo is going to use this endo sperm for energy to grow and, you know, turned into a sprout and you can't really see it. But there you can just make out this coding around the outside of the seed here, and that's gonna be a theme, tough protective shell that, uh, will allow the seed thio, you know, lay dormant for a long time and resist digestion for example, until the conditions air right for the, uh, seed to sprout. So essentially, uh, in a way, the adaptation of Pollen, The adaptation of seeds. Kind of a similar theme. They allow thes, you know, facets of reproduction to persist in a terrestrial environment much longer, rather than requiring, for example, the presence of water. Now, the last major evolutionary adaptation, I want to talk about our flowers and these air the reproductive structures of angiosperms. We're gonna talk about them in much more detail when we talk about angiosperms, but that the flower is one of the last major evolutionary adaptations of land plants. And it's in part due to the flower that angiosperms saw this explosion of diversification. Uh, they, in fact, what they saw was an adaptive radiation. So, uh, angiosperms actually are one of the most diverse groups of land plants around today, and it's in part because of the evolution of the flower. All right, that's all I have for this video. I'll see you guys next time