Lab: Fruit Fly Speciation

This experiment was an important piece of research that demonstrated the ability of isolation and differences in selective pressures to create different species. It provided laboratory based evidence that something similar could happen in the natural world.

Diagram of Fruit Fly Breeding Experiment demonstrating speciation

http://commons.wikimedia.org/wiki/File:Speciation_experiment.png#file

An experiment demonstrating speciation in the fruit fly (Drosophila pseudoobscura) was conducted by Diane Dodd. A single group of flies was divided into two, with one of the group fed with starch-based food and the other with maltose-based food. After the two groups had reproduced over many generations, it was observed that flies had changed. The groups were again mixed; it was observed that the flies now preferred mating with only those from their group. Source:http://commons.wikimedia.org/wiki/File:Drosophila_speciation_experiment.svg

Observe the diagram above and answer the following questions:

Identify these statement as True or False and defend your answer.

1.  The initial group of fruit flies is a population. True or False

Defense: _________________________________________________________

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2.  In the second stage of the experiment the fruit flies are still one population. True or False

        Defense: _________________________________________________________

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3. The fruit flies are isolated in the final stage of the experiment. True or False

        Defense: _________________________________________________________

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What is the selective pressure difference that investigation places on the Fruit Flies?