Totally Tolerant or Interestingly Intolerant

Younger students often have difficulty with the terms tolerant and intolerant related to water quality. They perceive intolerant as having a negative connotation. However, when referring to water quality the presence of intolerant organisms actually indicates higher quality water conditions. This activity will help the students understand this concept of tolerance.

Teachers: Click here to download the worksheets for parts one through three of this activity. Two of the four pages contain the information cards, and two contain cards with images of the organisms. Each student receives all four worksheets and should carefully cut-out each of the 18 cards.

Click here to download the Invertebrates Puzzle for part four of this activity.

Photocopy as necessary for your classroom.

  1. Have each student choose an organism (using the information cards) and have him or her note it's preferred temperature range. Move into a large area and have them stand. Give various temperatures. If a student's organism is able to tolerate the temperature they remain standing. If they are unable to tolerate it they should lay on the floor. Repeat with several different numbers. Discuss what may make a river or body of water change temperature. (Various types of pollution can increase the water temperature.) Those organisms that spent more time on the ground will only survive in the cleaner river.
  2. Have the students paste the image card of the organism on the other side of the information card. Have them sort the cards by tolerant and intolerant. Ask them which ones indicate unpolluted water. Calculate the range of dissolved oxygen for each organism. (high number minus low number) How does it correlate with tolerance?
  3. Examine the pH levels for intolerant, somewhat tolerant, and very tolerant. Notice the patterns. Discuss.
  4. Pass out the "Invertebrate Water Conditions Puzzle". Have the students use the information cards to determine which invertebrates could live in the water described in the boxes on the left. Next have the students label the condition as clean, somewhat polluted, or very polluted in the boxes on the right.

Note: The values given for this game are not actual figures but are used for the purpose of understanding the concepts of tolerance.

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Center for Global Environmental Education
Hamline University Graduate School of Education
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