Difficulty of Project
$ 20 - $25
Wear safety glasses, apron and plastic gloves.
Readily available from high school science labs. The fruit flies, Drosophila melanigaster, may be purchased from Carolina Biological Supply.
Approximate Time Required to Complete the Project
2 months.This includes xperimentation, collection, recording and analysis of data, summary of results and completion of bibliography.
To determine whether irradiation will produce mutations in fruit flies?
Materials and Equipment required
- Vials of Drosophila melanagaster (fruit flies)
- 10 lbs of bananas
- A fork
- Large measuring cup
- Tea strainer
- Large magnifying glass
- Small plastic spoons
- 2 bowls
- 4 glass bottles
- Paper toweling
- A camel hair brush
- Camera with zoom lens
- A scale borrowed from the school science lab
- Access to ultra violet radiation (2920 Angstrom units), hopefully provided and administered by your dentist or a local chemical lab
On the information level, this experiment serves to acquaint students with information on the current research on the effects of irradiation on the genes of fruit flies, namely, does irradiation produce mutations? Students acquire knowledge of the life cycle, the growth and reproduction of the fruit flies, the key physical characteristics of these flies, how to feed and maintain them, and the length of their life cycle which is short making them excellent candidates for genetic experimentation. In addition, since a great deal of work has been done on this topic, students may access previous studies and the outcomes derived from these studies.
This science fair experiment also serves to acquaint students with the essential processes of sciencing such as the importance of the use of a control, of identifying dependent and independent variables, of data collection, of pictorial and or graphic presentation of data and of being able to make better judgments as to the validity and reliability of their findings. They take on the role of scientists and in the process they learn to act as one.
- Drosophila melanagaster
- Ultra violet radiation
- Law of Dominance
- Law of Segregation
- Law of Independent Assortment of Factors
- Punnett Square
- Sex Linkage
- What are the characteristics of Drosophila melanagaster (fruit Flies)?
- How long is the life and reproductive cycles of Drosophila?
- How does one feed and maintain these fruit flies?
- Has ultra violet light been used to produce mutations in other organisms and what were the results?
- What kinds of research have been conducted on mutations in fruit flies and what were the results?
Terms, Concepts and Questions to Start Background Research
- What is a control? A control is the variable that is not changed in the experiment.
- What purpose does a control serve? It is used to make comparisons as to what changed or possibly caused the change.
- What are variables? Variables are factors that can be changed in an experiment.
- What is an independent variable? The independent variable is the one that is changed in the experiment.
- What is a dependent variable? The dependent variable is the one that changes as a result of the change in the independent variable.
- State the problem you are going to investigate in this science fair project.
- Create the data sheets you will use to record your observations. See above.
- Purchase and gather all your materials.
- Prepare the banana medium to feed the fruit flies. Dissolve 15g of agar in 480ml of water and bring to a boil. With a fork, mash a banana or push the banana through a strainer. Measure out 500g of the banana pulp and adds it to the agar. Pour this mixture into the bottles. Cut small pieces of toweling into strips and place two strips into each bottle. Now cover the bottles and tilt them to increase the surface area for the flies. When the mixture has set, open the bottles and insert the flies, cover each bottle with a thin layer of gauze. At the end of two weeks, repeat this procedure and transfer the flies into the new bottles. Use the camel hair brush to transfer them.
- With the magnifying glass, examine the fruit flies and record their prominent characteristics such as body color, gray or black, eye color red or pink, wing type long wings, vestigial wings and the sexes. You may wish to make labeled sketches of some of these flies in the before and then later, in the after stage.
- Anmrrange with your dentist or neighborhood chemist to have one bottle of flies irradiated with ultraviolet light. Use the lowest nanometer rating, 2920 Angstrom units for 30 seconds. The other bottle of flies will serve as your control. Make certain you have a description of the flies in your control bottle.
- Optional: You may try to photography your flies as close up as you can get.
- Observe your flies for the following three weeks. You will be viewing a new generation of flies. Were there mutations as a result of the exposure to UV radiation? Were there changes in the prominent characteristics? Compare these flies with the control group? What did you discover? What did you conclude?
- Record your conclusion.
- Prepare your report and include all of the following: a clear statement of the problem, your hypothesis, namely what did you predict would occur, and a list of the materials used. Include the safety precautions taken. Describe the procedures used. Include all the data that were gathered. Include all charts. Explain the purpose of the control. Formulate your conclusions. For dramatic value, you may include photos of the materials used or of you in the process of conducting this investigation. Include a bibliography of sources you used. You may wish to assess what you did and describe what you would do differently if you were to do this project again. What went wrong? What was very successful? You may wish to expand this research next year. What other materials might you investigate for this purpose? What advice would you give to your classmates if they planned to replicate this experiment?
Charting and or Graphing Data
In each section of the experiment, use charts to display the obtained data such the following sample:
Chart of Observations of Changes/Mutations
Samples of Fruit Flies
E.Morholt, P. Brandwein, A. Joseph: A Sourcebook for the Biological Sciences