Hi. In this video, we're gonna take a brief look at the history of life on Earth. And to begin that discussion, we need to take a look at the Earth itself. And first, we're going to examine the theory known as plate tectonics, which is basically the theory that the earth's crust this outer layer right here crust is basically made of large, solid plates that more or less float on the hot inner mantle. So here is the mantle. These are the inner and outer core. I'll just write cores. We don't need to worry too much about that. That's more the realm of geologists were just interested in, how the crust moves around on top of the mantle so that crust made of a solid, uh, plate, are made of solid plates, floats around on this incredibly hot mantle, the interior and those plates air actually broken up, as we see here in this image. Now you can see the continents and the oceans have been illustrated on this image, and the black lines through the image represent the boundaries of the various plates that, uh, the continent's rest on, and in some cases, their plates that don't have continents resting on them as you can see in the Pacific plate, for example, no continents there, whereas the North American plate you can see right here. This North American plate has both North America, Greenland, Greenland being this landmass right here and a little bit of eastern Russia, including the Kamchatka Peninsula. Right there. Now, what is the point of all this? How does this relate to biology? Well, because the earth's crust with the continents on it, aka Earth's landmasses, are on these plates, and these plates float on top of the mantle. Over time, these plates actually shift positions, they move around on the earth. As a result, we have something called continental drift, which is the movement of the tectonic plates, resulting in the shifting of the continents over time. So you may or may not be familiar with this image right here. The super continent, as it's sometimes called, that used to exist on Earth known as pan JIA. Now hang JIA was, as I said, a super continent, meaning it was a massive land mass made up of all of Earth's continents, kind of smashed together now, over time due to continental drift. These landmasses separated, and one of the first major separations that occurred is what we see in this image right here. And I'll just take myself out of the shot so you can see this better. And this you can see that Laura Asia, as it's called, includes what waas or what will be, I should say North America and Eurasia sort of this chunk I'm circling here, and this lower portion that I'm circling in red broke up into what is called Gondwana. Now, collectively, this formation of land masses is known as Gondwana land. And of course, it is made up of the two giant continents, Laure Asia and Gondwana, which will, of course, over time, break up into the continent's that we're familiar with today. All right, let's turn the page.