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Food Webs

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

The Science of Food Webs

This activity introduced students to the following properties of food.

  • Producers make all the molecules they need from simple substances and energy from the sun. Producers use solar energy to make the molecules they need from substances in the air, water and soil. During photosynthesis, producers absorb energy from the sun and use it to combine carbon from carbon dioxide with water to make sugars and other carbohydrates. Thanks to this amazing process, light energy from the sun is converted into chemical energy stored in the bonds between atoms that hold molecules together. Plants use the energy stored in these molecules to build other compounds necessary for life.
  • All other living things depend on producers for food. Consumers cannot trap energy directly from sun and must rely on molecules manufactured by plants for food.
  • Living things that must eat other organisms as food are known as consumers. 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.
  • Food webs show all of the interactions among the producers and consumers within an ecosystem. The general sequence of “who eats whom” in an ecosystem is known as a food chain. Energy is passed from one organism to the next at each step in the chain. Along the way, much energy is given off as heat. Most organisms have more than one source of food. The relationship among all energy flow interactions that occur within an ecosystem usually are described as a food web.  


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