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How to Record Dead Daphnia in Results

Daphnia are tiny, aquatic crustaceans that fill an ecological niche as plankton. They are frequently used in science experiments, both as subjects upon which the experiment is conducted and as materials used to feed animals or change an environmental variable. Because of their short life span, daphnia frequently die during experimentation. Dead daphnia must be recorded in results and if they are not, the experimental data may be skewed, inaccurate or misleading.

Instructions

- 1
  Record the precise cause of death for each daphnia if the daphnia themselves are the experimental subjects. If you don't know the cause of death, classify it as "unknown" rather than guessing. In order to come to an accurate, scientific conclusion you'll need to conduct another experiment.
- 2
  Illustrate the daphnia causes of death in a graph or chart that clearly represents the percentage of daphnia that died from each cause. Your chart should account for 100 percent of the total number of daphnia used in the experiment.
- 3
  Discuss the effect the dying daphnia have on the experiment and its conclusions in the discussion portion of your paper. Be sure to address whether dying daphnia prove or disprove your hypothesis, possible alternative explanations for dying daphnia and unknown variables.
- 4
  List the ways that dead daphnia could alter experimental results if the daphnia are food items or an experimental variable. For example, if you are studying jellyfish that feed on daphnia, be sure to address whether or not dead daphnia alter water pH, carry diseases, provide insufficient nutrition and other factors that could change the outcome of the experiment. Discuss the altered variables in your experimental discussion.

Animals & Science