Energy Flow


In nature, matter and energy are transfered or moved from one organism to another as well as from one organism to the environment. Scientist use different diagrams to represent the movement of energy and matter in the environment, including energy pyramids, food chains, and food webs. An important rule to remember is the 10% rule, which states that when energy moves from one trophic level to the next only 10% of the energy inside the food is transfered. This means that 90% of the energy inside the food is lost (mostly as heat). This helps explain why their are so few large predators compared to herbivores and producers.

Food_Pyramid.png Food_Chain.png


7.3B use models to represent aspects of the natural world such as human body systems and plant and animal cells.
7.3C identify advantages and limitations of models such as size, scale, properties, and materials.
7.5C diagram the flow of energy through living systems, including food chains, food webs, and energy pyramids.

PowerPoint Presentations:

Student Generated Food Webs:

During class, students generated their own food web by researching different organisms and using MS PowerPoint. Here are some excellent examples.


  1. Herbivores: organisms that only eat plants
  2. Omnivores: organisms that eat both plants and animals
  3. Carnivores: organisms that only consume other animals
  4. Trophic Level: the position of an organism in a food pyramid, food chain, or food web; in the pictures above, each trophic level is a different color.
  5. Producer: organisms found at the bottom of a food pyramid, chain, or web, like plants, that provide the energy to all other living organisms.
  6. Primary Consumer: organisms located above producers in a food pyramid, chain, or web; also known as herbivores.
  7. Secondary Consumer: organisms located above primary consumers in a food pyramid, chain, or web; can be carnivores or omnivores.
  8. Top Predator: a organism that is not hunted or eaten by an other organism.
  9. Decomposers: organisms that break down dead material from all trophic levels and return the nutrients contained inside it back to the environment.
  10. Nutrient: a compound needed by organims to survive
  11. Chemical Energy: the energy located in the compounds that make up an organism
  12. Radiant Energy: the energy provided by the sun. it used by most autotrophs during photosynthesis to create chemcial energy.
  13. Geothermal Energy: the energy created by the earth's core; it is used by some autotrophs to create chemical energy.
  14. Heat Energy: the energy resposnible for temeperature changes; it is the least useful form of energy.


Activity 1: Constructing a food Chain Diagram
  1. Visit the websites below and complete the activities to learn how to construct a food chain

Activity 2: Constructing a Food Web Diagram
  1. Visit the websites below and complete the activities to learn how to construct a food web

Activity 3: Creating your own Food Web
  1. Use any of the websites below to research an organism of your choice and learn about which organisms it eats to survive as well as organims that might eat it.
  2. Use this information and Microsoft PowerPoint to construct a simple food web that includes your organism. Your food web must include:
    • 5 different organisms, each labeled with its name.
    • All trophic levels, which are labeled
  3. Save your PowerPoint presentation as "LastName-Food Web" in my folder located on the shared OHenery (S:) drive.


Brain Pop: Food Chains (Username: txau_ohenry, Password: aisd)
Discovery Education: Food Chains and Food Webs (Username: student, Password: aisd)