Food chains track the progress of energy through organisms, and food webs show the interconnectedness between food chains. All food webs begin with the sun. Generally, plants take the energy from the sun to make their own food. Other animals then eat the plants to convert the plant's food into its own food. If a second animal eats the plant eater, then the meat from the plant eater becomes energy for the meat-eating animal. When the meat-eating animal dies, its body becomes energy for tiny bacteria and other decomposing organisms, which break its body down.

Producers in a food chain or food web take the sun's light and convert it into food through photosynthesis. This group composes the largest group of organisms on Earth. Sugar results from photosynthesis, wherein plants or algae take sunlight, carbon dioxide and water and produce food (sugar) and oxygen. Effectively, the sun's energy triggers the beginning of the energy transfer in the food web.

Producers make their own food, but the higher organisms must eat the plants or other animals to get their own food. Since they consume other beings, these organisms are known as consumers. Of these consumers, herbivores eat plants and predators consume other animals. Without the action of the producers to turn sunlight into food, the producers would die, and consumers that rely on them would lose their food source and die too.