 It makes sense that selective pressures can change gene pools. The next concept, this is another way that we can change gene pools and it's called gene flow. And I've come back to this visual of my own gene pool in my own house because this is going to help you visualize what gene flow is. Gene flow is immigration, that's new people coming into the population, or emigration, existing people in the population leaving. Immigration and emigration both are, I don't know if random is the right word, but it's not necessarily that there is a selective pressure. If there is a selective pressure that causes immigration or emigration, then maybe you're talking about natural selection changing the allele frequency. But in gene flow, all it is is that a group of people leave. Now, look at my family. This was me, remember, and this was my partner, and these are my kids, Keenan and Kai. The fact is, I mean, I'm not sure how I feel about this lecture because I turned into a grandma in one of the slides, and in this one, I'm going to have my children emigrate from my gene pool and leave, I think that this lecture sucks. Because yes, okay, fine, the allele frequency changed right. Now we have 50% little r's and 50% big r's, but the fellas left. Dude, what kind of lecture is this? That is an example of gene flow. Now, if like a whole population of Siberians came in and joined our family, okay, my kids aren't leaving anymore, they're just getting Siberian immigrants to come join our family. And let's just say that they're all non-rollers. What just happened to my gene pool? What? My gene pool totally changed. That's really fuel for evolution. That can cause evolutionary change or speciation, but it's random and it's caused by immigration or emigration, or people coming in or people leaving. The next one is really random. So you're going to have to take some time and visualize gene flow, flow, critters flowing from one population to the next population, coming in and leaving, that's what gene flow is. This next one is like a random disaster volcano picnic. I'll be right back to tell you about genetic drift.