(Intro)

This shouldn't come as a shock to you, but I am a living thing and I am sitting on some non-living things. I'm supported by a chair, a floor, and beneath that, the ground. So right now you are witnessing the exciting combination of two of Earth's systems. OK, maybe not that exciting, but just wait.

By now you're super familiar with the four spheres: the geosphere, the biosphere, the hydrosphere and the atmosphere, and every day just by walking around you, you are an example of the biosphere interacting with the geosphere. Most of the time we take the geosphere for granted. Sure, you may huff and puff when you walk up a hill, but do you ever stop to think about how the geosphere changes things?

So today we're going to take a couple of minutes to consider the ways in which the biosphere can be affected by the geosphere.

(Text: Big Question)

Think of it this way, all plants and animals need a space with the right temperature, moisture, and sunlight. They also need other living things around them right where they belong, it's their habitat. Now it might seem like the habitats of plants and animals just exist on top of the geosphere, but sometimes geology can have a huge impact on those habitats and the creatures that live in them.

And sometimes those changes just sort of happen and we have to look closely to notice the effect, but other times it's a huge, Earth-shaking event. Like seriously, Earth shaking. To see these effects in action, let's take a hike. We'll visit one of the most famous hunks of rock in the world, Mount Kilimanjaro in Tanzania, a country in Africa.

(Text: Investigation)

Kilimanjaro is a landform, a natural feature of the Earth's surface, so it's part of the geosphere, and it's covered in life: grass, shrubs, trees, insects, and other animals, it's practically a party. Well, a very orderly party. Let me explain.

A mountain, by definition, is pretty vertical. As we walk toward it you'll notice that the ground starts to slope up, and for a while the climate at the base of Kilimanjaro seems the same as the area around it: a grassy kind of land known as the savanna. The temperature here is warm year round, and it's mostly dry except for a short, very rainy summer season. The landscape is covered in shrubs and the occasional tree, and all our favorite Lion King friends live there. Also, this land is particularly good for farming, so it's full of one species: humans. Remember, people are part of the biosphere too.

But let's keep walking. The slope of Kilimanjaro forces air to move up, cooling and condensing and precipitating, or raining. So as we go higher, we enter a different zone: a rainforest. It's humid, rainy, and totally bursting with plant and animal life. Monkeys, birds and antelope call this part of the mountain home.

As we move even higher up on the mountain, you'll feel the temperature starting to cool. In general, temperatures decrease an average of 6 degrees Celsius for every 1000 meters you move up. So soon we'll hit an area that's much cooler and drier. The trees start to thin, eventually getting replaced by scrubby grass and low-lying shrubs. It can even get frosty at night. Here you may see an eagle fly overhead or some rodents scurrying across the ground. This area is called the moorland.

But our hike isn't done yet. After about six days of climbing we're coming close to the top of Kilimanjaro. Up here water is super scarce and it's cold. There's almost no plants or animals and the ground is covered in ice or just bare rock. Temperatures up here can go down to negative 18 degrees Celsius. This area gets so little rainfall that it's an alpine desert. It's kind of crazy, even as we're shivering up at the very top we can look down and see lions sunning themselves on the hot savannah below.

So, this one landform has generated four distinct habitats. The shape of the mountain changed the kind of plants and animals living on it. If the mountain weren't there we would just have flat grassy savannah everywhere but instead the geosphere created an environment where different plants and animals could flourish.

Of course the geosphere can sometimes have a more drastic effect on the biosphere, I promised excitement. What if our peaceful mountain was really a volcano. Well I'm about to blow your mind because it is. Kilimanjaro is a dormant volcano meaning that it's not active. So don't worry, scientists think it's last major eruption was about 360 thousand years ago. When a volcano erupts hot gas, ashes and lava flow out destroying all plants and animals in their path. Sad.

But the lava isn't all bad. Volcanic soil is very rich in nutrients so after the volcano has gone on its rampage, plants will grow bigger and more numerous on top. You might say that volcanoes are more extreme examples of how the geosphere can affect the biosphere.

(Text: Conclusion)

So if you're like me and you're a living thing then keep in mind that lots of non-living things in the world can affect the way we live. It may seem like the ground is just the stage where the show of life plays out but we've got to give the geosphere more credit than that. It's not just the stage, it's an actor too.