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WHERE DO FLIES COME FROM?
Background Information
Theory of Abiogenesis or Spontaneous Generation: The theory that some
organisms develop from non-living material.
Examples:
Until the 1600’s people believed that…
 Mice came from piles of straw.
 Rats came from piles of rags.
 Frogs and turtles came from rotting wood and mud at the bottom of
ponds.
 Rotting meat (flesh) turns into maggots causing flies to be formed from
rotting meat.
In 1668, Italian physician Francesco Redi challenged the belief that
decaying meat eventually turned into flies. He designed an experiment
to test his hypothesis.
Redi’s Hypothesis: “If flies come from eggs laid on decaying flesh by other
flies, then eggs will be visible near the decaying flesh because it serves as a
source of food for the developing flies.”
Brainstorm ideas for the experiment you are going to design.
Redi Experimental Design Activity
Learning Target: I will be able to design an experiment that tests a
hypothesis and contains a control, constants, an independent
variable, and a dependent variable. I will demonstrate this by
completing the Redi Experimental Design Activity. ***You do not have to
actually do the experiment you only have to design it!
Question: Do flies spontaneously generate (come from) meat?
Hypothesis: If flies come from eggs laid on decaying flesh by other
flies, then eggs will be visible near the decaying flesh because it serves
as a source of food for the developing flies.
Materials: What materials will you
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need?
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Procedure: Step-by-step directions for how to do your experiment.
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PLEASE IDENTIFY THE FOLLOWING PARTS OF YOUR EXPERIMENT!
Control: __________________________________________________
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Independent Variable: _____________________________________
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Dependent Variable: _______________________________________
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Constants: ________________________________________________
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Data: What data are you going to collect and how are you going to
collect that data?
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Diagram: Please draw a picture of what your experiment would look
like in the blank space below. LABEL YOUR DRAWING!