Drugged Out Daphnia

Category: Inquiry / Learning Cycle

Learning Objectives:

1. Students will design and conduct an experiment.
2. Students will evaluate other's experiments.
3. Students will describe the relationships between common drugs and heart rates.
4. Students will evaluate the impact that drugs have on animals within the biosphere.

   Materials, equipment and/or facilities:

   • Suspensions of nicotine, caffeine, aspirin, alcohol, sleeping pills
     
   • Recipes (Label each container with contents)
     
   • nicotine-soak cigarette or chewing tobacco in water for at least 2 hours, and filter through filter paper (to make approx 300 ml)
     
   • caffeine-dissolve 5-6 tablets of No-Doz or other brand in 300 ml of water.
     
   • aspirin-dissolve 8 tablets of aspirin in 300 ml of water.
     
   • alcohol-mix 10 ml of denatured alcohol in 300 ml of water.
     
   • sleeping pills- dissolve 5 tablets of sleeping pills (over the counter) in 300 ml of water.
     
   • Droppers (one for each suspension)
     
   • Culture of Daphnia (Can be ordered from any biological supply catalog)
     
   • Light microscopes
     
   • Microscope slides
     
   • Timers for groups (1 for each) (avg. class would need about 7)
     CAUTION: Instruct students not to taste any of the solutions.

   Sequence and duration of each part of lesson:
   Exploration stage (45 min):
   

   1. Place students in groups of 4-5 with one microscope for each group.
   2. Give groups two small jars or vials with fresh water for Daphnia.
   3. Have available all equipment and chemicals for students to use.
   4. Tell students that there are some common household drugs that are found in each of the suspensions. Also, tell students that there are little animals called Daphnia in the culture.
   5. Ask students to predict how the drugs will effect the Daphnia.
   6. Tell students to design and conduct an experiment to test the prediction.
      Specific Rules:
      • Students need to keep a detailed lab notebook for this investigation, complete with drawings and graphs.
      • Use a fresh Daphnia and slides after testing each drug (that is what the two jars are for).
      • Only add one or two drops of the drug to each slide.
      • Do not try to taste or partake of drug suspensions.
   7. Have students chart / graph their data, and write their conclusions.
   8. Have students clean up.

   Concept Invention stage (20-30 min):
   1. This part of the lesson should be teacher directed discussion, where data and concepts are compared and developed.
   2. The teacher should start the discussion by asking, "What kind of conclusions did you come up with?"
      • The teacher should make sure that all groups report, and the findings are written on the board.
      • The teacher should make sure that the relationship between the drugs and heart rates are developed.
      
      
   3. The teacher should then ask, "What data do you have to support your findings?"
      • The teacher should write these by the conclusions from #2
      • A follow-up question to each presentation of data should be, "Does anyone have data that would support or refute these findings?"
   4. The teacher could ask any of the following questions:
      
      • Do your findings support your hypothesis?
      • What do you like about each others experiments?
      • If you were to do this again, what would you change? Why?

   Application stage (15 minutes): There are a few suggestions below for possible applications.

   • Give each group a dropper-full of one of the drugs, but do not tell them what it is. Ask them to identify which drug it is based upon the Daphnia' behavior.
   • Give each group a combination of two drugs and tell the students what combination it is. Ask them to predict the behavior of the Daphnia, and test their prediction.
   • Ask students to write a half page paper on how nicotine can end up in an eagles' system.

   Evaluation:
   Possible suggestions for assessment:
   • If students can perform the applications in the previous section, then they have sufficiently reached the objectives.
     
   • Students could be asked to exchange lab notebooks, and have the groups try to evaluate their experiment.
     
   • Students could write a newspaper article of any type that follows a part of a Daphnia' life, during or after it has come in contact with the drugs. Make sure that the students cover all the drugs and describe the behavior afterwards.

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   Copyright 1996. Utah State Office of Education, Curriculum Section, 250 East 500 South, Salt Lake City, Utah, 84111.

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