Natural Selection Simulation

http://phet.colorado.edu/en/simulation/natural-selection  [click "run now"]
or..

Click to Run

Pre-Lab Questions – Answer them in your Eco-Log in complete sentences. (don’t copy Qs)

1.        What variables can you influence in this lab?

2.        Define what a genetic mutation is. How do genetic mutations happen?

3.        What selection factors might effect an animal population besides the ones used in this lab?

4.        What sorts of selection factors do you think affect real animal populations that are endangered?

The Experiments:

You will observe what happens to the population of rabbits based on their characteristics and factors in their habitat.

Fill in the blanks in the following hypotheses to state your prediction of how the three possible mutations will affect the population of rabbits under various selective factor pressures and in different environments:

Hypothesis: (fill in the blank here and copy your FIRST hypothesis into your EcoLog)

1.     In the equatorial environment, (white or brown) ______________ rabbits will survive best when wolves are introduced.

2.     In the arctic environment, (white or brown) ______________ rabbits will survive best when wolves are introduced.

3.     In the equatorial environment, (long teeth or short teeth) ______________ rabbits will survive best when food is the selective factor.

4.     In the arctic environment, (long teeth or short teeth) ______________ rabbits will survive best when food is the selective factor.

Now run the simulation for each of your hypotheses (you will run the simulation 4 separate times):

1.     After you start the simulation “add a friend” and select your mutation (for hypotheses 1 and 2 the mutation is “brown fur” for 3 and 4 it is “long teeth”)

2.     After the 3^rd generation pause the simulation and record data about the population of rabbits… total, brown and white.

3.     Un-pause the simulation and add your selective factor.

4.     Let the simulation run for 4 more generations then pause it and record data about the rabbit population again

Your data table for each simulation should look something like this for Hypothesis #1 – put it in your EcoLog under Hypothesis #1:

·       Write your hypotheses and create data tables in your Eco-Log for hypotheses 2, 3 and 4.

·       Use the population numbers from the simulation graph to get you numbers for the tables, remember you can zoom in and out on the chart to get more accurate reads.


Inquiry Bonus Question!

• What do you think would happen if you ran one of your simulations in equatorial conditions again but after the 6^th generation you switch the environment from equatorial to arctic? Write a hypothesis about this and create a data table which measures the rabbit population at the 3^rd, 7^th and 10^th generations. 

Post-Lab Questions - Answer in your EcoLog in full sentences

1.        Based upon your evidence from the simulation what conclusion are you able to make about what happens to animals that cannot compete as well with other animals in the wild?

2.        Why does the make-up of the population change over time when selective factors are introduced?

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

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

5.        Describe three ways you think humans might act as a selective factor for an animal or plant species.