 All right, our next example is called genetic drift. Genetic drift. And when I think, ooh, that was a cool little tortly wits on the F, when I think about genetic drift, I think about like drifting like a piece of leaf, drifting on a river. It's just kind of randomly moving like it's random. That's the most important thing that I want you to remember, to distinguish between flow, which was immigration or emigration. And there's no question that there could be some randomness in who emigrates or who emigrates. But genetic drift is a change that happens like something totally random and bizarre happens. So I've got two examples of genetic drift. It's most significant with small populations, and this is the reason why. There's a phenomenon called the bottleneck effect. Bottle neck effect. And I'm going to give you this example. So you have a population of critters and some random disaster takes place. And I'm not using my house as an example anymore because my kids already left me and I'm a grandma, so I really don't need any kind of random disasters in my house. So let's imagine a population of like cheetahs. And in fact, they think that this actually happened to cheetahs and that's why cheetah genetics, what cheetahs are all so closely related to each other. They think that cheetahs went on a picnic. Just kidding. I'm making this part up. So if the cheetahs went on a picnic and most of the population went on the picnic, but a few of the punks, maybe they got in trouble, they weren't allowed to go on the picnic, so they had to stay home. And then at picnic land, a volcano exploded. And so everybody who went on the picnic, done. It was random, but now there's like five cheetahs left. And they're the five cheetahs that have to repopulate all cheetahdom. Like all the cheetahs on the planet have to come from these five cheetahs. It's considered the bottleneck effect because there used to be a whole bunch of cheetahs, but then there was this huge bottleneck and now we only have five. It was random. It's not like the cheetahs that got killed were too slow or were susceptible to volcano explosions. It was totally random who ended up going on the cheetah picnic and who didn't. And the end result is that you have a very small number of cheetahs to repopulate the whole population. That's going to mean that you're going to instantaneously change your gene pool because now we're just taking our gene pool from a really small group. There's another flavor of genetic drift, random, and that's called the founder effect. That says effect. The founder effect is this like a brave group of cheetahs decide they're going to, like they're sick of this garbage and they're going to go found their own population, a small group of them. Actually, let's keep it random. A small group of cheetahs, they were on their way to the picnic in the volcano, but as they were walking to the picnic, they saw a boat and they decided to get on it and then the boat like carried them to a desert island and now then their boat floats away and they can't get back. This is a great story. At least it's not my kids that got stranded on the desert island. So the five cheetahs are now stranded on the desert island. They are founding a whole new population of cheetahs and no question, the genetics are going to be different. Has nothing to do with who's successful, who has the rock and jeans, anything. It just is random who happened to get on that boat and float to the island and have the boat disappear. The key with genetic drift is that it's a random process as opposed to flow where we actually have a group coming into a population or a group leaving and affecting the, what's the word, allele frequency that way, okay. Now I've already prepared all my materials and my next section is called natural selection. It seems kind of odd since we already talked about it and I realized that what I really want to show you is artificial selection because humans can manipulate natural selection by deciding who gets to make babies with who. Oh, wait till you see this next section. It's artificial selection. But I have to find my button so that I can turn off the recording.