As a result animals are considered consumers. At the end of an animal's life something must happen to their bodies. The nutrients that come from this decomposition become part of the soil that is re-used by new plants, back at the start of the food chain. The following site has a fun activity that your teacher might help you set up in class. Although it is difficult to say, in general, how changes in our environment will effect a food chain this activity will let you explore all the complex relationships that are part of an ecosystem.
Wetlands provide many services for both humans and ecosystems.
To get an idea about the importance of wetlands, look out across the landscape you live in. Animals may hide out all over the landscape, but they always come back to water and they seldom stray very far. When a wetland is destroyed, a cascade of things happen to the surrounding environment. First of all, all of the good things I mentioned above stop happening. The loss of each individual wetland is a small step toward jepordizing the health of the entire ecosystem surrounding it.