Algae use sunlight to make their own food. They are producers. Producers make their own food.

Water fleas eat algae. Small fish eat water fleas, and a heron can eat the fish. These animals are consumers. Consumers eat other living things.

The arrows in this food chain point from the organism being eaten to the organism that eats it. They show the direction in which energy is transferred. Bacteria and fungi break down dead organisms. These decomposers release nutrients that plants and algae can use again.

A food web connects several food chains. Many animals have more than one food source.