This is unit three populations AP environmental science. My name is Mr. Chipman. I teach biology AP biology at Murray High School in Murray, Kentucky. 3.2 K selected are selected species. What is this selected business? It's called selection theory. Selection theory has to do with the quality and quantity idea, right? Some animals go for quality, some animals, plants go for quantity, right? Both of those are successful reproductive strategies, but just looking at the differences and understanding those differences, I think is helpful for us. So, a K selected species. Um, so the the K and the R, they have to do with symbols from other things that we're going to look at. K is a carrying capacity. R has to do with like R max and exponential growth, which we'll look at in a second. So typically a K selected species a species that has they're larger like an elephant but not necessarily elephant sized like elephants are the largest land mammals. So, we're not that's just an example cuz I like elephants. I mean, look at them. Look at them, right? But any kind of large animal typically, uh, long lifespan, late maturity. When when we say maturity, we're talking about sexual maturity. Uh reproduce few offspring. Um but high parental care, typically involved in a K selected species, not always, but usually uh populations remain close to the carrying capacity, which is K in stable environments, meaning that there's not a lot of fluctuation in that population. We're going to look at carrying capacity in a later section. Um, competition between limited resources is usually pretty high for most K selected species. Um, elephants, humans, humans are kind of weird because we kind of are, we don't really fit in, you know, we're not competing with elephants, but we'll talk more about humans later. Whales, great example. Bears, all the things that I like. Okay, selected species. Um, they're usually more negatively affected by changes as well. So like an invasive species, they're usually slower to recover after any kind of disturbance because of that longer lifespan, longer reproductive times. Um here's this is typically the graph that you'll see associated with a K selected species. We're going to talk more about these graphs later, but a logistic growth graph uh usually represents a species that is affected by limiting factors in a population and is also going to match up closely with what is called the carrying capacity again which we will look at later. Our selected species, this is an oyster. All oysters are great examples of an R selected species. uh typically smaller body size, shorter lifespan, early maturity, lots of offspring, little to no parental care. Uh population has these short sort of boom bust cycles, right? They fluctuate far from carrying capacity. We're going to see in a graph what we mean by that. Actually, we'll go back to this graph. I think it's really good to show you that. Uh all over the place, right? All over the place. So there's there's they're not really dealing with a carrying capacity sort of thing with our selected species. Um competition is usually pretty low because of the their ability to rapidly colonize an area and kind of move in. Uh mice, great example, mosquitoes, dandelions, um any sort of like annual plant is going to work that way. Um where they just sort of come back later, that kind of thing. um less resistant or are they're less impacted, excuse me, by invasive species. They rebound quickly after disturbance because of that their ability to reproduce quickly. And that brings us to this idea. Well, here's a here's a growth uh chart for our select species typically going to be using this exponential growth sometimes called a J curve. We'll get into J curve S-curve again. This brings us to this idea of biotic potential. Simple idea, right? biotic life potential potential, right? It's the maximum reproductive rate of a population under ideal conditions. If everything was ideal, if there's no factors being limited, this is their biotic potential. It's going to be much higher in an R selected species than a K selected species due to their rapid ability to rapidly reproduce, right? It's a continuum, meaning that there's like a scale, right? Uh because a lot of species don't fit neatly into one category or another. Sea turtle is a great example. I'm going to use sea turtles as examples. Moving on, uh they lay lots of eggs, but they can live long. Their life can be very long, right? If they're able to make it to adulthood. They usually live a long time. Um and then, you know, some species like coral are able to reproduce quickly, but are also highly affected by the environmental change. So, I think it's important to note that they don't always fit in easy boxes. Few things do. Uh here's an example. This is a zebra muscle. Zebra muscles is an invasive species itself. It's an R selected species able to out compete native muscles which are K selected species and reproduce slowly. Uh big big problem zer muscles um if you like to read about that kind of thing. It's it's interesting. A lot of times you don't think of muscles as being interesting but I think they're a particular invasion is a very interesting story indeed. There's a classic K selected species, the whitetail deer. Very common in North America, all over North America. Different different kinds of whitetail deer all over the place. Um recovery is very slow for an animal like this. And so you typically have uh their populations managed because if they are depleted, it's very hard to bring them back from the brink, so to speak. And so that's why deer hunting is is controlled and a good it's a good thing. So let's look at a let's look at a practice problem. Population of deer produces one or two fonts per year which stay with the mother for an extended period. In the same forest, a mouse population reproduces multiple times a year with large letters with little parental care. Which conclusion best fits ecological principles? The deer have a higher botic potential. They don't. So I'm going to move on. I'm already done with that because they don't. Uh, we talked about that deer are less vulnerable to invasive species. They're not. They are more vulnerable, right? Because they're they're slower reproductive times. Mice are specialists. They're not. They're generalist. A, B, and C are wrong. D has to be correct. I don't even have to read it. But let's look at it anyway. There are selected. It's true. Dear case selected, reflecting different survival and reproductive strategies. Perfect. Hopefully this was helpful. 3.3 right around the bend.