In this video, we're going to differentiate between grazing food chains and detritus based food chains. First, recall from our previous lesson videos that the term "trophic level" refers to an organism's position in a food chain or a food web. Trophic levels include primary producers, primary consumers, secondary, tertiary up to quaternary consumers, and decomposers as well. A grazing food chain is a food chain where the primary consumers feed on live plants. All of the food chains that we've looked at so far in our course have been grazing food chains.
So, it's nothing new. A detritus based food chain, on the other hand, is a food chain where the primary consumers feed on detritus, which recall is just dead organic matter and waste. It is possible for a single organism to participate in multiple food chains, including a grazing food chain and a detritus based food chain. Just as you can see down below, the screech owl is participating in both food chains. It's also possible for a single organism to feed at different trophic levels in different food chains.
So, it's possible for a single organism to serve as a primary consumer in one food chain but then to serve as a tertiary or quaternary consumer in a different food chain. That being said, let's take a look at this image down below where we can further differentiate between a grazing food chain here on the left and a detritus based food chain here on the right. The main differences are at the primary producer level and the primary consumer level. For a grazing food chain, the primary producer is going to be alive, which is why we're showing you a live plant here. The primary consumer is going to be an herbivore that consumes the living plant or the living primary producer.
For a detritus based food chain, the primary producer is going to be detritus, which again is just going to be dead organic matter and waste. Here we're showing you a dead plant. The primary consumer in a detritus based food chain is going to be a decomposer and or a detritivore, which would consume the detritus. Here we're showing you an oyster mushroom. The black arrows that you can see throughout this image indicate the path that nutrients take through the food chain.
What you'll notice is that when all of these organisms at each of these trophic levels die, the nutrients and chemicals that they contain can end up cycling back to these fungi and bacteria that serve as decomposers. These decomposers are the recyclers that complete the chemical cycling within the ecosystem. Every single ecosystem is going to rely on these decomposers and contain decomposers to complete the chemical cycle. However, the rates of decomposition can be different in different environments. The last note that I'll leave you all off with here is that decomposition rates actually have a tendency to increase with increasing amounts of these three factors, which are temperature, moisture, and oxygen.
This is why decomposition rates tend to be greatest near the equator, which has the highest amount of precipitation and the highest temperatures on average as well. This here concludes our lesson, and moving forward, we'll be able to get some practice. So I'll see you in our next video.