# data[].attributes.headline
Explore pictures of a marine food web and read about the different trophic levels (producers, consumers, and decomposers).

# data[].attributes.subject
Explore pictures of a marine food web and read about the different trophic levels (producers, consumers, and decomposers).

# data[].attributes.attachment_link.readable_text
This lists the logos of programs or partners of NG Education which have provided or contributed the content on this page. Leveled by

Encyclopedic Entry Vocabulary

Every living being is part of a food chain. Food and the animals that eat the food make up a food chain. For example, plants and grasses are food for zebras. Zebras are food for lions. Plants, zebras, and lions make up a food chain.

There are many different food chains in an ecosystem. All together, the food chains in the ecosystem make a food web.

Trophic Levels

Organisms in food webs are grouped into categories. These categories are called trophic levels.

Producers

Organisms in the first trophic level are called producers. Plants are producers. Algae and some bacteria are also producers. Each producer makes its own food. Most producers use photosynthesis. This is a series of chemical reactions. Plants use these reactions to make energy from sunlight, carbon dioxide, and water.

Consumers

The next trophic levels are animals that eat producers. These animals are called consumers.

Consumers can be carnivores or omnivores. Carnivores only eat meat. Omnivores eat both meat and plants.

The first level of consumers is made of herbivores. These animals are also called primary consumers. They eat plants, algae, and other producers. Deer, mice, and elephants are herbivores. They eat grasses, shrubs, and trees. In the desert, a mouse is a primary consumer. It eats seeds and fruit. In the ocean, many fish and turtles are herbivores. They eat algae and seagrass.

Secondary consumers eat herbivores. In a desert, a secondary consumer may be a snake. It eats mice. In underwater kelp forests, sea otters are secondary consumers. They hunt sea urchins.

Animals in the next level are called tertiary consumers. They eat secondary consumers. In the desert, an owl or eagle may hunt snakes.

Top predators are also called apex predators. They eat other consumers. No other consumers eat them. Lions are apex predators on the grasslands of Africa. In the ocean, the great white shark is an apex predator. In the desert, bobcats and mountain lions are top predators.

Detritivores and Decomposers

Detritivores and decomposers make up the last part of food chains. Detritivores eat plants and animals that are not alive. For instance, vultures eat dead animals.

Some organisms, like fungi and bacteria, are decomposers. They turn decaying plants into soil. Decomposers allow food chains to start over. For example, grass makes its own energy through photosynthesis. A rabbit eats the grass. Then a fox eats the rabbit. When the fox dies, worms and fungi break down its body. The body returns to the soil. There, it leaves nutrients for plants to grow.

Biomass

Biomass is the energy in living organisms. Producers use the sun's energy to create biomass. The higher the trophic level, the lower the biomass. There is more energy in lower trophic levels than in higher ones.

There are always more producers than herbivores in a healthy food web. A healthy food web has many producers and many herbivores. It only has a few carnivores and omnivores.

Every part of a food chain is connected to other food chains. When one part is in danger, others are also at risk. If plants are destroyed, herbivores don't have enough to eat. Their numbers go down. The number of plants can decrease because of drought or disease.

Humans can also destroy food chains by destroying habitats. People cut down forests. We use the lumber for buildings. We also pave over grasslands to build shopping malls or parking lots.

Bioaccumulation

Sometimes, pesticides can affect food chains. Pesticides get into the soil and water. Animals eats plants that are covered in pesticides. The pesticides stay in the animals' fat. When a carnivore eats that animal, it also eats the pesticides. This is called bioaccumulation.

Bioaccumulation happens in water ecosystems, too. Runoff from cities or farms can be polluted. Algae, bacteria, and seagrass absorb the pollutants. Sea turtles and fish eat the seagrass. Then, sharks or tuna eat those fish. When people finally eat the tuna, that meal is full of pesticides.

In the 1940s and 1950s, bald eagles began disappearing. One major cause was a pesticide called DDT. The name DDT stands for dichloro-diphenyl-trichloroethane. It was used to kill insects that spread diseases. DDT builds up in soil and water. Worms, grasses, algae, and fish ate organisms with DDT. Bald eagles ate the fish. They had high amounts of DDT in their bodies. They got it from their prey. These eagles started laying eggs with thin shells. These shells often broke before the baby birds hatched.

The U.S. government decided to ban DDT. Food webs have come back in most parts of the country. Bald eagle chicks are now able to hatch.

Credits

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.

Writers

Kim Rutledge
Hilary Costa
Erin Sprout
Santani Teng
Melissa McDaniel
Diane Boudreau
Tara Ramroop
Jeff Hunt
Hilary Hall

Illustrators

Mary Crooks, National Geographic Society
Tim Gunther

Editors

Jeannie Evers, Emdash Editing
Kara West

Educator Reviewer

Nancy Wynne

Producer

Caryl-Sue, National Geographic Society

Sources

Dunn, Margery G. (Editor). (1989, 1993). "Exploring Your World: The Adventure of Geography." Washington, D.C.: National Geographic Society.

Last Updated

Nov. 7, 2012

User Permissions

For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, 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.

Writers

Kim Rutledge
Hilary Costa
Erin Sprout
Santani Teng
Melissa McDaniel
Diane Boudreau
Tara Ramroop
Jeff Hunt
Hilary Hall

Illustrators

Mary Crooks, National Geographic Society
Tim Gunther

Editors

Jeannie Evers, Emdash Editing
Kara West

Educator Reviewer

Nancy Wynne

Producer

Caryl-Sue, National Geographic Society

Sources

Dunn, Margery G. (Editor). (1989, 1993). "Exploring Your World: The Adventure of Geography." Washington, D.C.: National Geographic Society.

# data[].attributes.attachment_link.description
This lists the logos of programs or partners of NG Education which have provided or contributed the content on this page. Leveled by Encyclopedic Entry Vocabulary Every living being is part of a food chain. Food and the animals that eat the food make up a food chain.

# data[].attributes.headline
BrainpPOP video about food chains--Quiz will be posted next for practice after you've watched! 

# data[].attributes.subject
BrainpPOP video about food chains--Quiz will be posted next for practice after you've watched! 

# data[].attributes.attachment_link.description
Predator or prey, consumer or producer? How about all of the above? Tim and Moby talk about how the food chain connects every species.

# data[].attributes.attachment_link.description
Learn more and understand better with BrainPOP's animated movies, games, playful assessments, and activities covering Science, Math, History, English, and more!

# data[].attributes.headline
Great article from TIME magazine for you to read!

# data[].attributes.subject
Great article from TIME magazine for you to read!

# data[].attributes.attachment_link.readable_text
A food chain shows how energy passes from one living thing to another. The great white shark is at the top of the ocean food chain. Read on to learn more.

ILLUSTRATION BY DARBY MINTER FOR TIME FOR KIDS

1.The Sun Light from the sun gives plants energy.

2. Seaweed This plant soaks up sunlight.

3. Fish Some fish eat plants to live. The plants give the fish energy to move.

4. Seal A seal is a carnivore. It eats the fish.

5. Great White Shark This predator is a quick and powerful hunter. It eats the seal.

# data[].attributes.attachment_link.description
A food chain shows how energy passes from one living thing to another. The great white shark is at the top of the ocean food chain. Read on to learn more. 1.The Sun Light from the sun gives plants energy....

# data[].attributes.headline
Enjoy this interactive game that allows you to build a food chain!

# data[].attributes.subject
Enjoy this interactive game that allows you to build a food chain!

# data[].attributes.headline
Food chain and food web vocabulary cards for you to study with!

# data[].attributes.subject
Food chain and food web vocabulary cards for you to study with!

# data[].attributes.attachment_link.title
Food Webs and Food Chains for Kids | Science Lesson for Grades 3-5

# data[].attributes.attachment_link.description
What is the difference between food chains & food webs? Watch our food webs & food chains video for kids in 3rd, 4th and 5th grade to learn about it!