Biogeography and Species-Area Curve

by Jason Amores Sumpter
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bio geography has large scale effects on communities and species diversity, especially in regards toe latitude in area. First, let's take a look at how latitude is going to affect things. Differences in latitude will lead to differences in climate, and differences in latitude will also result in differences in sunlight and precipitation. For example, we know the tropics relieve or rather receive ample sunlight and ample precipitation. This leads to lots of EV apa transpiration, which is the evaporation of water from the soil and plants moving into the atmosphere. And this helps make this a very moist, humid, warm climate, which allows for very rich species diversity. Now the relationship between species and area is modeled here in the species area curve, but you can see in this graphic. Basically, the trend is that larger areas have larger numbers of species, so as you increase the area, you're also increasing the number of species. The last model I want to look at is what's known as the island Equilibrium model, and this is basically looking at the balance between species immigration and extinction rates that helps maintain stable species counts. Now, on our X axis here basically have a number of species. And on this side we have our extinction rate. And here we have our immigration rate. And what's important to know is as you increase uh, well, hopefully what you can see is that the balance between the immigration rate and the extinction rate is what's going to determine the species number on the island. So if you have a lot of immigration and a small amount of extinction, you're going to have ah lot of species on your island. So, for example, here, you know where it says large island nearby. We're gonna have a good amount of immigration and a low amount of extinction. And that's going to give us a pretty high number of species, not something to obsess over. Just something to sort of understand how community structures work. All right, that's all I have for this lesson. I'll see you guys next time