Food Web

Author: Jennifer Hernandez

Overview: Students will learn use an interactive web-based food web game to gain familiarity with trophic levels and interactions.

Lesson Concepts:

  • In an ecosystem there are four basic trophic levels: producers, primary consumers, secondary consumers, and tertiary consumers.

  • An organism is considered to belong to a certain trophic level based on what it eats.

  • Skill: Students learn to use keys in a graphical and an intuitive manner to identify specimens.

  • All the organisms in an ecosystem depend on other organisms to exist.

  • The diversity of an ecosystem decreases when species become extinct in that ecosystem.

  • Skill: The students gain experience in computer use and Internet navigation.

Grade Span: 7–8

Materials:

  • Computers with internet access. Internet access is not necessary if the website is saved on each computer prior to the lesson.

  • To decrease the difficulty of the game, we recommend preparing a printout listing all the clues that are otherwise provided throughout the course of the game. The clues are provided as the player clicks on photos of various organisms and are designed to help the player determine the proper placement of the organisms in their respective trophic level and position.

Advance Preparation:

  • It is advised that the teacher play the food web game prior to teaching the lesson.

  • A basic knowledge of the four specified levels of a food web is necessary. The food web game uses a marine ecosystem to depict interactions between trophic levels. For the introduction, the use of a habitat that the students are familiar with will facilitate the discussion of trophic interactions and biodiversity.

Time: One class period (45-50 minutes)

Procedure:

  1. Introduce terms that the students need to know for the food web lesson: producers, consumers (primary, secondary, and tertiary).
  2. Draw a basic food web on the board leaving the squares blank (see below). List the following organisms and plants next to the diagram: grass, acorn, flower, caterpillar, bee, deer, squirrel, jay, spider, mountain lion, and hawk. Have the students decide where the organisms go, then connect with arrows to show the interactions between the groups. This will model the computer activity.

    Sample food web

  3. Ask students the following question, "Why are food webs important and how are they related to biodiversity?" To break down this question, ask the students what would happen to the deer population if there were no mountain lions? If there was a large increase in the deer population, what would happen to the grassy meadows? This line of questioning can continue until the students can answer the question about biodiversity and food webs.
  4. Students break into groups of 3-4 students.
  5. The food web game is found at the following website: http://www.blue-iceberg.com/features/featurefoodweb.html
  6. The play time can be extended by having students play repeatedly to gain higher scores.
  7. Discussion suggestions: Students can construct a new food web for another habitat type such as the rainforest. Students can also discuss how the marine ecosystem would change if certain species became extinct or had large decreases in population size.
 
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