Abiotic factors and an organism's range

0:00- [Instructor] So let's talk a little bit about abiotic factors for an organism's range. So before we even get into it, let's just think about what these words mean. In other videos, we've talked about how abiotic, that means non-living, biotic would refer to living.

0:14So this is non-living factors for an organism's range. What do we mean by range? In everyday language, you could say, "Where do you range, where do you go?" And it's a similar meaning right over here. An organism's range is the geographic area where the organism can live.

0:32So let's just think about some of those factors. Well, maybe one of the more obvious ones might be whether an organism can live on land or live in water. For example, let's say that there is an island. Let me draw it in a better color here. Let's say there's an island here and it is surrounded by water.

0:53And if you have some animal here that needs to live on land, well, then its range is definitely going to be limited by the water around it. So it's only going to be able to stay on that island. Likewise, there might be some other creature inside the water here that can't go on land, and so its range is going to be limited to that water.

1:16It won't be able to go on land. And you could even imagine it could be some type of an inland pond, or maybe it's a lake of some kind. So this is all land on the outside, and this is water right over here. And so if this thing needs to live in the water, well, it's definitely going to be limited.

1:35Its range is gonna be limited to that water. But it's not just about whether there's land or whether there's water or whether you can cross from one to the other. There's also a lot of other things that could be physical barriers that keep an animal from going one place or another, like land or water or mountain ranges or rivers.

1:57But it could also be factors that determine where an organism can survive or is more likely to survive. For example, this picture right over here, this is a world map, where it shows us where we have reef-building coral. All these little brown spots are where you have actual reef-building coral.

2:17And you might notice something. They are all relatively close to the equator or in the tropics. They're at relatively low latitudes between 30 degrees north latitude and 30 degrees south latitude. And in other videos, we have talked about, those are the parts of the earth that are warmer, and if we're talking about the seas, the parts of the seas that are warmer.

2:40And that is the case that reef-building coral needs reasonably warm waters. Not too warm, but reasonably warm waters. And that's why you don't see it in these colder latitudes further to the north or further to the south. So temperature, whether you're on the water or you're on land.

2:58For example, most of us, if you go to Antarctica, we would have trouble living there without a significant use of technology. And that's why if you go really into the interior of Antarctica, away from the coast, you see almost nothing that is living there. So temperature matters, access to moisture or water matters.

3:17So are we in a swamp, are we in a desert? One of those might be better for one type of species than another. If we're talking about a water-dwelling creature, can matter what's in the water. What is the acidity of that water? What is the salt content? Are we talking about saltwater, freshwater, or something in between?

3:36And then there's other factors like floods and wildfires and volcanic eruptions that can also affect all of that. Now, we aren't done talking about all the factors for an organism's range. We just touched on the abiotic factors in this video. But you could imagine there's also biotic ones like access to food or other organisms that might view you as food.