When the feeding relationships among the various organisms in an ecosystem form a network of complex interactions ecologist describe these relationships as a FoodWeb. Consider, for an example the relationships in a salt marsh. Although some producers including marsh grass are eaten by water birds, grasshoppers, and other herbivores, most producers complete their life cycles, and die. De-composers convert the dead plant matter to detritus, which is eaten by detritivores, such as sand hoppers. Then the detritivores are eaten by small fish. Add mice, large fish, and hawks to the scenario, and feeding relationships can get very confusing.
Food Chain:
The energy stored by producers can be passed through an ecosystem along a Food Chain, a series of steps in which organisms transfer energy by eating and being eaten. For example, in a prairie ecosystem, a food chain might consist of a producer, such as grass, this is fed upon by a herbivore, such as a gazing antelope. The herbivore is in turn fed upon by a carnivore, such as a coyote. In this example of a land food chain the sun and waters energy is used for the grass to grow in order for it to be fed to a small insect such as a grasshopper. Grasshopper is then fed to a snake. Snake is then eaten by a hawk.The hawk will eventually die off after completed its life cycle and turn to fungi just like in the beginning.