All organisms are linked through feeding relationships. There are many feeding relationships in any ecosystem but energy always flows from primary producers to various consumers. These feeding relationships are represented by food chains and food webs.

A food chain is a series of steps in which organisms transfer energy by eating and being eaten.

Here is an example of a food chain. Notice that the arrows point in the direction of the energy flow. The point of the arrow goes to who is doing the eating. Use the pull down menu to label each organisms as producer or consumer.

In most ecosystems, feeding relationships are much more complicated than the relationships shown in a food chain. A network of feeding interactions is called a food web. Look at the simple food web below. This shows a more realistic feeding pattern. Use the pull down menu to label each organism as herbivore, carnivore, omnivore, or decomposer.