Natural Selection

Designing the Experiment

Click on the link above to access the activity. During this simulation, you will be controlling the mutations (brown fur or white, long tail or short, and long teeth or short) and environment (equator or arctic) of a population of rabbits. You will also be able to control selection factors (limiting factors) such as wolves and food.

Experiment by selecting different environments, phenotypes, and selective factors. Observe what happens to the rabbit population.

Copy the following chart into your notes. Fill in the chart after you observe what happens.

For each of the experiments, begin by adding a friend and a mutation. Wait until there have been a couple of generations before adding the selective factor. After adding the selective factor, let the simulation run for another 3 or 4 generations.

Use the data from the graph produced during the simulation to help support your conclusion/ observation.

Post-Lab Questions

Copy the following questions into your notes and answer them.

1. Based upon your evidence from the simulation, what conclusion are you able to make about each of the three different types of phenotypes in rabbits?

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   Check Your Answer

   Answers will vary, but you should notice that in this simulation the phenotype of fur color was important to the survival of the rabbit, depending on the environment chosen (equator or artic) when the wolves were chosen as the selection factor. The long teeth phenotype was important when food was chosen as the selection factor. The tail length phenotype did not seem to have much of an effect.

2. What happens to animals that cannot compete well with other animals in the wild?

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   Check Your Answer

   Animals that cannot compete as well as other animals in the wild will die and won't be able to pass on their genes to offspring.

3. Sometimes animals that are introduced into an area that they've never lived in before out-compete and endanger resident species. Why do you think this happens?

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   Check Your Answer

   These animals are better suited to the environment and compete with the original animals for resources.

4. If only one species is considered the "fittest," why are there still so many variations among species? Why do some birds have very long pointy beaks, while other birds have short flat beaks?

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   Check Your Answer

   There are many different resources available in the environment. Birds that have long pointy beaks are best suited for eating one type of food, while birds with short flat beaks are better suited for eating another type of food.

5. How do you think diseases can affect natural selection?

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   Check Your Answer

   Disease can wipe out an entire population of animals. If animals are resistant to the disease, they will survive and pass on the disease resistant genes to their offspring.