Biotic and Abiotic Factors

by Jason Amores Sumpter
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when we look at ecosystems, we're gonna want to examine the biotic factors and a biotic factors. Now, the biotic Factors of living components. This not only includes the organisms, but actually the interactions between organisms as well. Now the non living parts of the environment where the A biotic factors are gonna include things like temperature, moisture, oxygen and sunlight. You can see a bunch of those in this image here just highlighted. Now a biotic factors they're gonna have quite an influence in an organism's distribution and behaviors. They're going to limit where the organism can survive and also in part determine what the organism has to do to survive. Now it's gonna be the interplay between biotic and a biotic factors that determine the distribution of the species. And you can see a nice map of the distribution of a species here. We're actually looking at the distribution of the common juniper. It's a little Conifer plant. It's where juniper Berries come from. If you've ever heard of those now, geologic activity or geologic changes, I should say will have a huge impact on the distribution of species. I mean, you know, we just mentioned how the movement of the continents has played a huge role in determining the history of life on the various continents on Earth. Um, other factors will also play a role inthe e distribution of species like dispersal, which is the movement from the location of birth to breeding site. For some organisms, this isn't gonna be very far. However, there are some organisms that migrate huge distances to get to their breeding sites. And, you know, they could be separated by oceans or vast stretches of land mountains. So the, you know, geologic, uh, factors involved are going to play a big role in this. Now range is the actual geographic distribution of the species. And for example, you know, we just saw the range of the juniper up there. However, thing the you know, uh, the range of an organism can is not necessarily confined toe. One continent is the point I want to make. Now, the Wallace line is an interesting bio geographical division between Asia and Australia. That kind of illustrates this point nicely about how organisms are going to be limited. Maybe not the right word affected. Maybe a better word by geologic changes. So let me jump out of the way here. Hopefully, you look at this map and you recognize that we are looking at Southeast Asia and here's Australia. And you know, all these islands in here. We have, you know, in the, uh, well, parts of Indonesia. And, um, you know, this isn't a geography lesson. So the point I want to make about the Wallace line is that during during the last ice age, they're essentially ah, lot of water waas frozen. So the ocean levels were reduced, and as a result, uh, landmasses looked a little different. Now, here you can actually see what the landmasses, uh, in theory would have looked like by these sort of beige outlines. So, you know, uh, highlighted darker like around and hear those air the actual continent lines today with our, uh, current ocean levels or currency levels. However, you can see that when the ocean levels were lower, there was more land area. Now, the point about this Wallace line is that it's a division between Asia and Australia, and you can see there's other lines in here. You know, I don't want you to worry about that. We're just gonna look at this Wallace line. That kind of goes along here, and he he's basically o r sorry. This line, which is named after this guy, Wallace. The idea is basically that this division existed between these two land masses that prevented a spread of species between them. Right, Uh, you're not gonna find species that are, you know, both somewhere in here and also somewhere in here on. You know, you're not gonna find ancestors of species over here, for example, over in this area. And that's because there was this barrier that separated them. And, you know, even though the landmasses were shaped differently, there was still this actual, you know, water division between them that, uh, you know, separated the diversity of life between these land masses. Uh, in case you're curious, that water division existed because there's actually very deep trench in the ocean there that ensured there was still gonna be a water barrier between those two land masses. Now, exotic species are gonna be non native species to an area, and sometimes these exotic species will actually do really well in this new environment, and they'll spread, and then they'll actually compete with local flora and fauna and they can actually disastrous effects on ecosystems. Here, this looks like a harmless little organism. It's called a zebra mussel. This organism is just wreaking havoc in the Great Lakes, in America and really in freshwater all across the country. Um, you know, these organisms are super invasive, and they totally change ecosystems because they basically they end up eating a lot of their filter feeders. They end up eating a lot of stuff out of the water, which allows for more light to get in and that causes, you know, much greater blooms of algae, for example. So, you know, uh, the point is, they have a major effect on the ecosystems and they throw them out of balance. And so invasive species are usually, ah, bad thing. You don't want invasive species, exotic species. On the other hand, that just means that they're not from the area. So I just want to sort of point out that the invasive has more negative connotation exotic, not necessarily a negative thing. However, exotic species can become invasive. No, with that, let's go ahead and turn the page