This video, we're going to talk about density-dependent factors and how they limit population growth. Density-dependent factors, as their name implies with the term dependent, are going to have limiting effects on population growth that are directly dependent on population density. If you change the population density, then you'll also change the effects that these density-dependent factors have on limiting the population's growth. Often, these density-dependent factors will have an impact that intensifies as population density increases. Most, but not all, of these density-dependent factors are going to be biotic in nature, meaning they're associated with life.

Notice that down below in our image, we're showing you just a few examples of density-dependent factors, which includes things such as resource or water availability, predation, disease, competition, waste accumulation, and limited space. As an example to help you better understand how the impact intensifies as population density increases, you can imagine a scenario where as population density increases, the resources in the environment, such as food and water, become exhausted and depleted. This means that there won’t be enough resources for all of the individuals in the population, leading to increased death rates and decreased birth rates. In a graph, like the one that you can see down below right here, which has population density on the x-axis and mortality rate on the y-axis, you might expect this graph to look something like this for density-dependent factors. As the population density increases, the impact on the population's growth intensifies, so the mortality rate is going to increase as well. It's important to note that as population density increases, the population will approach what's known as its carrying capacity, which is often abbreviated with the letter K and represents the theoretical maximum population that an area can sustain at any given time.

As the population density increases, it approaches the carrying capacity and the impact of these density-dependent factors will intensify. This conclusion concludes our lesson on density-dependent factors. In our next lesson video, we'll talk about density-independent factors. I'll see you all there.