Deserts tend to be around 30 degrees latitude north and south, basically just outside of that tropical region, and they're usually found in the interior of continents. Now, most people tend to think of deserts as just being really hot all the time, whereas the temperature in deserts is highly variable, both seasonally and daily. In fact, temperatures can vary by as much as 40 degrees Fahrenheit in a given day. Could you imagine going from 80 degrees during the day to 40 degrees at night? I can't even imagine temperature changes like that on a daily basis. We also know, hopefully, from our discussion of the Hadley cell, why rainfall is so low in deserts. Right? Because of those atmospheric circulations that cause all the precipitation to get sucked up by the tropics, so that none is left for those poor deserts. But they're surviving. Right? In fact, there is lots of life in the desert. Now, there's not a ton of vegetation. It tends to be mostly scattered with lots of bare patches of earth. However, there is some. It doesn't all look like this sea of dunes you see here in this image. And most organisms that live in deserts tend to have water conservation adaptations. For example, reptiles, which are common to deserts, have scales made of keratin, which creates an impermeable barrier for water and helps prevent water loss from the body. Perhaps even more famously, cacti have adaptations that allow them to store fluids in their bodies. And additionally, it should be noted that animals have learned to exploit those storage abilities of cacti, so life is ever evolving. Now here we have this nice global map, which lets us see the major deserts distributed across the globe. And really all I want to point out is just how you can see that you have that tropical band in the middle, and then desert on either side of that. So, this is the tropical region, and then we have desert, and more desert up here. Of course, there are exceptions, there's always exceptions, but just as a general trend, something to bear in mind.

Now, the savannah is a biome that usually occurs around the equator, and it's cool. It's kind of found as a transition zone between forest and desert, or forest and grassland. That's why it tends to be mostly made up of grasses with some small woody plants. However, it does have some scattered trees, as you can see in this picture here. Of course, you wouldn't call that a forest by any means, but there are some trees. The savannah will, or rather savannahs will, usually be found around the equator, and their rainfall will be highly seasonal. In fact, they can have dry seasons that can last, you know, most of the year, almost the whole year. Because of that, the plants of the savannah have to be drought tolerant as it could be a really long time before they're going to see any rainfall. Also, because the dry season can last so long, wildfires are fairly common, which is why most savannah plants are also fire tolerant. I mean, if you can't regrow from, you know, your average regular run-of-the-mill wildfire, you're not going to last long here, kid. So with that, let's go ahead and flip the page.