Resource Library

ENCYCLOPEDIC ENTRY
ENCYCLOPEDIC ENTRY

Consumers

Consumers

Every food web includes consumers—animals that get their energy by eating plants or other animals.

Grades

5 - 8

Subjects

Biology, Ecology

Image

Grasshopper Eating Leaf

Grasshoppers are primary consumers because they eat plants, which are producers. Producers are the base of the pyramid, the first trophic level.

Photograph by mchin

On a sawgrass prairie in the Florida Everglades, an alligator (Alligator mississippiensis) lazes on the bank of a slow-moving water channel. A great egret (Ardea alba) stalks fish in the shallows. A grasshopper (Brachystola magna) chews on an aster leaf. A raccoon (Procyon lotor) digs in the mud for freshwater mussels. These animals are quite different from one another and live in different ways, but they have something in common: In this ecosystem, they are all consumers.

Within every ecosystem, organisms interact to move energy around in predictable ways. These interactions can be represented by what scientists call a trophic pyramid. Primary producers—plants, algae, and bacteria—make up the base of the pyramid, the first trophic level. Through a process called photosynthesis, producers capture energy from the sun and use it to create simple organic molecules, which they use for food.

Consumers constitute the upper trophic levels. Unlike producers, they cannot make their own food. To get energy, they eat plants or other animals, while some eat both.

Scientists distinguish between several kinds of consumers. Primary consumers make up the second trophic level. They are also called herbivores. They eat primary producers—plants or algae—and nothing else. For example, a grasshopper living in the Everglades is a primary consumer. Some other examples of primary consumers are white-tailed deer that forage on prairie grasses, and zooplankton that eat microscopic algae in the water.

Next are the secondary consumers, which eat primary consumers. Secondary consumers are mostly carnivores, from the Latin words meaning “meat eater.” In the Everglades, egrets and alligators are carnivores. They eat only other animals. Most carnivores, called predators, hunt and kill other animals, but not all carnivores are predators. Some, known as scavengers, feed on animals that are already dead.

Some consumers feed on live animals but do not kill them. For example, small arachnids called ticks attach themselves to other animals and feed on their blood, but ticks are not considered predators. They are instead called parasites.

Some secondary consumers eat both plants and animals. They are called omnivores, from the Latin words that mean “eats everything.” A raccoon is an example of an omnivore; it eats plant matter such as berries and acorns, but it also catches crayfish, frogs, fish, and other small animals.

Ecosystems can also have tertiary consumers, carnivores that eat other carnivores. A bald eagle is an example of a tertiary consumer you might see near the coastal mangrove islands of the Everglades. Its diet includes predatory fish that eat algae-eating fish, as well as snakes that feed on grass-eating marsh rabbits. It is considered a “top predator” because no other animals native to the ecosystem hunt or eat it. When a top predator dies, it is consumed by scavengers or decomposers.

In addition to consumers and the producers that support them, ecosystems have decomposers. These organisms get their nourishment from dead organic material, such as decaying plant leaves or dead fish that sink to the bottom of a pond.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Director
Tyson Brown, National Geographic Society
Author
National Geographic Society
Production Managers
Gina Borgia, National Geographic Society
Jeanna Sullivan, National Geographic Society
Program Specialists
Sarah Appleton, National Geographic Society, National Geographic Society
Margot Willis, National Geographic Society
Producer
Clint Parks
other
Last Updated

May 20, 2022

For information on user permissions, please read our Terms of Service. If you have questions about licensing content on this page, please contact ngimagecollection@natgeo.com for more information and to obtain a license. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. She or he will best know the preferred format. When you reach out to him or her, you will need the page title, URL, and the date you accessed the resource.

Media

If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.

Text

Text on this page is printable and can be used according to our Terms of Service.

Interactives

Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.

Related Resources