Chapter 2. EVOLUTION II—SELECTION

PopG and Morphs Exercise Independent Simulation

Post-Lab—PopG and Morphs Exercise Independent Simulation
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PROCEDURE

Decide on a biological system to model and determine which one of the conditions required for genetic equilibrium will be modified.

Besides fitness values and population size, you can also control the mutation rate and the amount of gene flow. Be sure to manipulate only one condition.

In your lab notebook, describe your independent simulation and include values for all of the PopG parameters for your simulation.

Record your predictions of what you think will occur to the allele frequencies based on your simulation in your lab notebook.

Run your simulation five times. Record the outcome each time in a table you create in your laboratory notebook using Table 2-3 as a template.

Table 2-3. Data from five separate simulations.

In your laboratory notebook, answer the following question:

How well did your predictions match the simulated values?

Be prepared to present and discuss your results in the next lab meeting.

As you prepare for your independent experiment using the PopG program you will need to think about what is the correct type of data to collect and analyze to address the model you are testing. To help you better understand some ways in which the data can be gathered and transformed, view the following video:

PopG Data Analysis from Hayden-McNeil on Vimeo.

Examine the Impact of Mutation on Evolutionary Change

The role of selection and mutation in the process of evolution is often hard to fully appreciate, owing to the long time periods required to see the impact of this process. Using the web-based simulator “Morphs,” you will be able to simulate the effect of selection and mutation on the morphology of an organism.

You will need to access this assignment using Internet Explorer. To access the program, go to the Morphs link:

http://www.introbio.biology.lsu.edu/tutorial/Morph/index.html

In your laboratory notebook, answer the following question:

Based on your understanding of natural selection, what is the impact of an increase in mutation on the process of natural selection?

Once you have the program running, complete the following exercises (you may want to show the genotypes).

PROCEDURE

  1. Beginning with whatever structures (morphs) the computer has generated, and setting the mutation rate to “HIGH,” select for morphs that you think look closest to a straight line as the parents for the next generation (Figures 2-8 and 2-9).
Figure 2-8. Initial setting prior to selecting or producing offspring showing genomes for each morph.
Figure 2-9. Generation 1 results from child 4 and child 6 in generation 0.
  1. Continue the process of reproduction and selection until 5 of the 7 offspring are just a single straight line (Figure 2-10).
Figure 2-10. Results at the end of one simulation.
  1. In your laboratory notebook, record the number of generations required for this to occur.
  2. Turn the mutation rate “Off,” return to generation 1, and perform the same process. If you can achieve it, record the number of generations required to create 5 straight line offspring out of 7.

In your laboratory notebook, answer the following question:

Which simulation generated the straight lines in the fewest generations?

  1. Choose a mutation setting and then begin selecting for whatever shape you want.

When you have produced offspring with your chosen shape, print the page showing the offspring and record the mutation setting and the number of generations required.

In your laboratory notebook. answer the following follow-up questions:

What is the relationship between the rate of evolutionary change and mutation rate?

How do the concepts of natural selection, mutation, genetic equilibrium, and evolution fit together?