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Food Webs

Author(s): Nancy Moreno, PhD, and Barbara Tharp, MS.

What Is a Food Web?

Begin the activity by asking students, Do you know what a food web is? Lead a class a discussion about the different organisms found in different environments (such as oceans, forests, lakes and deserts). Remind students that living things are classified as either producers (organisms that use solar energy to make the molecules they need from substances present in the air, water and soil) or consumers (which live directly or indirectly on food provided by producers). Explain to students that the general hierarchy within an ecosystem of which organism eats which is known as a food chain, and that the relationship among all interactions that occur in an ecosystem usually are described as a food web.

Follow by asking, Do humans eat only one kind of food? Then ask, Can you name an organism that is a herbivore, a carnivore, an omnivore, or a decomposer/scavenger? Remind students that herbivores (primary consumers) feed on plants and other producers. 

  • Cows, camels, caterpillars and aphids are herbivores. 
  • Carnivores (secondary consumers) feed on other animals.
  • Lions, owls and lobsters are carnivores. 
  • Omnivores eat plants and animals. 
  • Pigs, dogs, humans and cockroaches all are omnivores.
  • Decomposers and scavengers feed off the dead remains and waste of other organisms at any step along a food chain. Scavengers, such as vultures and flies, feed on remains of animals that have been killed or that die naturally. Decomposers live off waste products and parts of dead organisms. Many kinds of bacteria and fungi (molds and mushrooms) are decomposers.

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932