 Ecosystems are large, often highly complex areas of our environment. In today's video, we will be discussing some of this complexity as it relates to how different aspects of an ecosystem interact with one another. As we discussed in a previous video on ecosystem components, ecosystems are composed of both biotic or living and abiotic or non-living components. Let's start by discussing the abiotic parts of an ecosystem. Light precipitation, soil composition, temperature, and air currents are all examples of abiotic components that can be found within an ecosystem. While each of these components is important by itself, how they interact with each other also greatly influences their environment. For instance, in places like tropical rainforests precipitation almost always comes in the form of rain because of the high average temperature. However, in places like temperate forests where temperatures are much more variable, a much wider variety of precipitation types exist. Even though the two habitats are both dominated by trees, the difference in temperature ranges results in vastly different precipitation types and amounts. The variation in temperature and precipitation also affects the local wildlife, a biotic component, and helps determine which species can survive in a given ecosystem. The biotic components of an ecosystem also interact with one another, much like the abiotic components. One of the best examples of this is how the various trophic levels interact with each other. A trophic level is how scientists classify animals based on their food preferences. At the lowest trophic level are the herbivores, those animals that primarily eat plants. In the next highest trophic level are the animals that eat the herbivores as well as some plants, known as omnivores. The highest trophic level is the carnivore, and is represented by animals such as wolves, lions, and eagles. Each of these trophic levels interacts with the other, either directly or indirectly. A direct interaction between trophic levels usually takes the form of one organism consuming another, such as when hawks eat mice. An indirect interaction can be a bit harder to see, but often occurs when there is an intermediate step involved between two trophic levels interacting. Using the previous example, berries frequently consumed by mice are able to grow better as a result of the hawks eating those mice. In this example, the interaction is the hawk aiding the berries growth by consuming the mice that eat them. Which trophic level do you think has the most direct interaction with other trophic levels? Pause the video and have a think. If you said the intermediate trophic level, or the one that contains omnivores, you're right. Omnivores tend to eat a much wider variety of organisms than either of the other two trophic levels. This variety in their diets leads to them having more direct interactions than other trophic levels. Relations within an ecosystem can also occur between abiotic and biotic components. One great example of this is when weather patterns like thunderstorms cause forest fires and alter the habitats of the organisms living within the forest. While not always the case, interaction between ecosystem components are often great catalysts for evolution. But that's a topic for another video.