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

Food Webs

Environments, such as oceans, forests, lakes and deserts, are homes to different communities of organisms. Within each distinct environment, plants, animals and other living things must find ways to obtain water, food and other necessary resources. Different kinds of organisms have different needs. As seen in the previous activities, plants need air, water, nutrients (usually from soil) and light. Animals need air, water and food.

All animals depend on plants and other producers. Some animals eat plants for food. Other animals eat animals that eat the plants, and so on. Some organisms even feed on waste and dead material. The general sequence of whom eats whom in an ecosystem is known as a food chain. Energy is passed from one organism to another at each step in the chain. Most organisms, however, have more than one food source. Thus, a web, which depicts all of the different foods eaten by each animal, is a more accurate model of interactions within an ecosystem.

This activity lets students construct possible food webs for different ecosystems, as they learn about the roles of different kinds of living organisms.

Complete instructions for conducting activities in this slide set, including materials needed, setup instructions, student sheets (in English and in Spanish), answer keys and extensions, can be found in The Science of Food Teacher’s Guide, which is available free-of-charge at


1. Remind students of the previous activity in which they explored plants that people eat. Ask, Do people only eat one kind of food? What kinds of food do people eat? Explain to students that most other animals also have several food sources, although not all animals are omnivores (eat plants and animals).

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

Houston Endowment Inc.

Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education