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Biological Energy - Extinct or Not!

Over the years, there have been many animals which were well-known that have become extinct. To be extinct means that there are no longer any reproducing organisms of a species on Earth. Examples of animals that have become extinct include each dinosaur species, the dodo bird, and the passenger pigeon. Your goal will now be to learn how the extinction of one organism can affect other organisms that are in the same food web. Throughout this activity, try to relate what you learn with how energy flows through the different levels of the food web.

The Food Web Activity
Get a group of friends together in a large circle. Go around the circle labeling each person as a producer, primary consumer, secondary consumer, tertiary consumer, or decomposer. Hopefully your circle will be large enough so that you have several people with the same function.

Take a ball of string or yarn and toss between different people in the circle. Make sure that when you get the string or yarn that you do not let go of it.

  • Start with a producer and toss to a primary consumer.
  • Go from primary consumer to secondary consumer.
  • Continue from the secondary consumer to a tertiary consumer.
  • Go from the tertiary consumer to a decomposer.
  • Repeat with a different producer.
  • It is acceptable for a single person to get the string more than once. Just make sure that you hang on to each length of string that you get.
  • Each length of the string represents the flow of energy in the food web.

As the string is being tossed to everyone, check and make sure that the string (food) web is accurate.

Now comes the "extinction" part. Imagine that a problem has happened and that a producer has become extinct.

  • One person who is a producer drops his/her string(s).
  • Everyone who is holding onto only the string that touches the extinct organism raises his or her hand.
  • Notice how many people can be affected by the extinction of a producer!

Now try a comparison extinction. Everyone who had dropped their part of the string picks it back up. This time you will see what happens when a primary consumer (like a grasshopper) becomes extinct.

  • One person who is a primary consumer drops his/her string(s)
  • Everyone who is holding onto only the string that touches this extinct organism raises his or her hand (unless you are a producer.)
  • Notice how many people can be affected by the extinction of a primary consumer.

Research Activity
Research current or past extinctions using the Internet or a library. Try to find arguments for and against saving different species. In other words take a position for or against allowing a specific species to become extinct.

An internet site you might consider including:

Analysis:

  1. How are organisms related in a food web?
  2. Describe what happens if one or more organisms becomes extinct?
  3. What species seem to be more important species in keeping the flow of energy going?
  4. What difference is there in the effect of removing a producer compared to a primary consumer on a food web?
  5. Are there species we should try to save from becoming extinct?
    • How do we make these choices?
    • What influence can an individual, such as yourself, have on the extinction of an organism?
utah state board of education This Sci-ber Text was developed by the Utah State Board of Education and Utah educators.