 Flowers use their beautiful petals and fragrance to attract insects. Why do they do that? Because the insects help them in pollination. So in this video, we're going to see what pollination is, what are the different types, and how exactly do the insects help. So let's start with what is pollination? Pollination is simply the act of transferring the pollen grains from the anther, these are the anther, the top part of the male organs, to the stigma. Stigma is the top part of the female organ. So let me just show that. Here is the pollen grain sitting on the anther, top part of the male. Here is the stigma, top part of the female. The act of transferring that pollen grains from the anther all the way to... So let me just try. From the anther all the way to stigma. That's basically what we call pollination. That's what pollination is all about. Now, based on whether the pollen grains are transferred within the same plants, or they're transferred between two different plants, we can classify them into two kinds. So the first one we'll call self-pollination, self-pollination. And the second one would be something called cross-pollination. Let me just write that correctly. All right, cross-pollination. So let's start with the self-pollination. What exactly is this? So as the name suggests, if the pollen grains are transferred within the same plant itself, then we'll say it's self-pollination. So one way that can happen is if you have pollen grains transferred within the same flower, so from the anther to the stigma of the same flower, this is self-pollination. But even if you have pollen grains transferred from the anther to the stigma of a different flower belonging to the same plant, I'll call this number two, this is also self-pollination. Why? Because still the pollen grains are being transferred within the same plant. The pollination is still happening. The plant is still pollinating itself. That's the whole idea behind self-pollination. So these are examples of self-pollination. For the first one to happen, the flower needs to be bisexual, meaning it has to have both the male and the female reproductive parts. Only then it can do this. On the other hand, if the flowers are uresexual, then they can still self-pollinate this way. A male flower can transfer pollen grains to a female flower belonging to the same plant. On the other hand, what do you think is cross-pollination? Can you guess that now? What do you think is cross-pollination? Well, cross-pollination is transfer of pollen grains from one flower to a flower of a different plant or a different tree. So for example, if you have pollen grains from here going all the way to the stigma of a different flower altogether, meaning flower belonging to a different tree altogether, then that is what we call cross-pollination across two different plants. Of course, same species, obviously, but two different plants altogether. So I'll call this as number three. This is in pink, so this is cross-pollination. Now you might say, cool, but how exactly does the pollination happen? How do the flowers take the pollen grains and transfer it to the stigma? They don't have any moving parts now, do they? Well, that's a great question. So the pollination depends on certain agents. Let me just write that down. Depends on certain agents. Agents are basically things that help in pollination. One of the most common agent would be wind. So the pollen grains will just get sprayed into the air, and then the wind will be the one that carries it forward. And because both the pollen grains and the stigma is very sticky, and the pollen grain comes very close to that stigma, it'll just stick to it. And of course, in some cases, they are not sticky, but they're very hairy. Even then, the pollen grains will get entangled very nicely with the stigma and they get stuck to it. And pollination happens. So with wind, self-pollination can easily happen because they're very close to each other, right? The stamen, the pollen grains and the stigma are very close to each other. So with wind or water, just like how wind helps in transferring pollen grains for land plants, water will help in transferring the pollen grains in aquatic plants. But what about cross-pollination? Now you see, for cross-pollination to happen, the pollen grains need to get transferred from one plant or from one tree to another. Now if these trees are very far apart, then the chances of cross-pollination reduces, right? So how do we effectively increase the chances of cross-pollination? This is where the insects coming to the picture. So another important agent for pollination, especially cross-pollination, would be insects. Insects like bees, butterflies, moths, and even birds. But how exactly do the insects pollinate? Let me take an example of a bee over here. Let's say this bee is flying and it's a little hungry and it spots a flower. The flower attracts the bees by using its beautiful petals, its odor, and also by using the nectar. Now what exactly is nectar, you may be asking? Well, nectar is this sugary stuff that the flowers produce near its base, base of the flower, which has a lot of sugar, it has a lot of protein, so perfect for these hungry bees. So what these bees do, they get attracted to that particular flower, they sit on that particular flower and they start drinking that nectar. And as they start drinking that nectar, the pollen grains start sticking to the bees. Let me show you a couple of photos of that. Here on the top, you can see a bee drinking nectar from the flower. And as a result, you can see it's resting its legs on one of the anthers. And so pollen grains can easily stick to the bee. In the second case, you can see a lot of pollen grains sticking to this bee. This bee has been super busy. So coming back to our story, a lot of pollen grains can easily get stuck to this bee. So pollen grains get stuck to that bee. Let me now get rid of this photo. And then when the bee decides to move away, it carries those pollen grains with it. Now the bee goes on its way, on its journey, long journey maybe to its home, and then it spots another similar flower with the similar fragrance and the similar odor. And then again, it gets attracted to it and starts drinking the nectar from that. And while doing that, some of the pollen grains get transferred to the stigma, and that's how cross-pollination can happen. But it's important that the bees need to get attracted to the same species of the flower. For example, if this is a papaya flower, it needs to transfer that pollen grains to another papaya flower and not maybe watermelon flower. And it's for that reason, usually certain bees are always attracted to certain kinds of flower that increases the chances of successful cross-pollination. Okay bee, you're done your job, go home. These bees turn out to be a major contributor of pollination. Okay? Now of course, the pollination has happened, but that's not the end of the story. It's actually the beginning of the story. Remember, the sperms inside the pollen grains still need to travel all the way into the eggs which are found in the ovaries. And that is something we'll talk about in the future video. So what did we learn in this video? We learned about what pollination is, which is basically the transfer of pollen grains from the anther, the top part of the male, to the stigma, the top part of the female organ. And this can happen in two ways. Self-pollination is when the pollination happens within the plant. This can happen within the flower or within two different flowers of the same plant. And cross-pollination is when pollination happens within two different plants. So from one flower of one plant to a flower of a different plant altogether. And then we saw the agents are basically what causes pollination. The examples of that would be wind and water. And certain insects also help in pollination.