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Fruit Flies

How quickly they grow!

Because of their rapid life cycle, fruit flies are perfect for observation. In just two weeks time, you'll be able to observe the birth, growth, reproduction, and death of these organisms.
Materials
Small glass jars or beakers
Cheesecloth to cover the tops
Rubber bands to fasten the cheesecloth
Overripe bananas
Fruit flies
Magnifying glass

Procedure
Place a few slices of the banana in the bottom of the glass jar and mash them slightly so that they stick to the glass.
Add a few (5-8) fruit flies* to the container.
Quickly cover the top with the cheesecloth and fasten it tightly around the rim with a rubber band.
Observe through the jar what happens each day for two weeks.

*Note: If you don't have fruit flies available in your classroom lab materials, you can "catch" some by placing your glass jar (with the banana in it) near a source, like garbage cans. To help attract the flies, place a small cardboard tube (or a rolled up piece of construction paper) in the jar near the banana. It may take a few days, but the fruit flies will be attracted to your jar.

Conclusions
The fruit flies should begin to lay eggs in the banana within a few days. The larva should then move to the sides of the jar. A few days later, the larva should change to a pupa. A few days later, the pupa should hatch into fruit flies.
You should be able to see the life stages and distinguish between the adult and newborn flies.

Extension Ideas
Compare the life cycle of the fruit fly with the life cycle of other animals, like butterflies, chickens, and puppies. Consider which is most similar to the fruit fly.

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