Name:______Date______Period____

Evolution in Guppies Simulation Lab

The purpose of this activity is to analyze how guppy populations change over time. The simulation activity allows you to observe how the gene pool of the guppy population for coloration changes after many generations with and without the presence of large predatory fish. The simulation will help you understand the pressures that drive guppy evolution.

Adapted from PBS

Go to the PBS “Sex and the Single Guppy” Evolution Simulation Lab http://www.pbs.org/wgbh/evolution/sex/guppy/ (Which you can access from my website by opening the Guppy Simulation Lab document in the Evolution folder and right clicking to open the hyperlink.)

Introduction:

View the Guppy Gallery

1.  After viewing the different guppies describe the different coloration patterns for male vs. female guppies.

Select the Predator Gallery tab (bottom right corner tab within the guppy gallery)

2.  Describe the average size of the following predatory fish:

A.  Rivulus

B.  Blue Acara

C.  Pike Cichlid

Select the Habitat Gallery tab (bottom right corner tab within the guppy gallery)

3.  Describe how the different habitat conditions would affect the predator populations.

Click on “I’m Ready to Find out”

4.  Read the text book. Who is John Endler? What did he study and why?

5.  Before you start the simulations get the information about the 3 pools. Click on the number of each pond (orange lettering which can make the numbers hard to see.) Fill in the chart to describe the coloration and predator levels in each of the three pools.

Location / Coloration of Male Guppies / Number of Pike / Number of Blue Acara / Number of Rivulus
Pool 1
(furthest upstream)
Pool 2
Pool 3
(lowest pool)


6. How does this pattern of predators in these three pools relate to the information from the habitat gallery (note the location of each pool)?

7. Develop your own hypothesis about guppy coloration. The hypothesis should answer the questions: Why do guppies in different areas of the stream have difference in coloration? (You can choose from the list on the simulation, or make up your own)

Your table pair will be assigned 2 of the simulations below to run. You will compile the data with other groups in your same row. When you press run the simulation, immediately hit stop simulation so that you can get the starting data for generation 1 (as closely as possible). You will then need to start over to let the simulation go through at least 8 generations. Remember that the process of adaptation takes time.

Conditions / % of Brightest / % of Bright / % of Drab / % of Drabbest
1 / Coloration: Even Mix
Predators: Rivulus only / Initial
After 8 generations
2 / Coloration: Even Mix
Predators: Rivulus, Acara / Initial
After 8 generations
3 / Coloration: Even Mix
Predators: All Three Types / Initial
After 8 generations
4 / Coloration: Mostly Bright
Predators: Rivulus Only / Initial
After 8 generations
5 / Coloration: Mostly Bright
Predators: Rivulus, Acara / Initial
After 8 generations
6 / Coloration: Mostly Bright
Predators: All Three Types / Initial
After 8 generations
Conditions / % of Brightest / % of Bright / % of Drab / % of Drabest
7 / Coloration: Mostly Drab
Predators: Rivulus only / Initial
After 8 generations
8 / Coloration: Mostly Drab
Predators: Rivulus, Acara / Initial
After 8 generations
9 / Coloration: Mostly Drab
Predators: All 3 Types / Initial
After 8 generations

Summary

8. Describe how natural selection by predators influenced coloration. Give data from one of the trials to support this conclusion (be sure to include predator conditions for trial in your discussion).

9. Read the summary of results. What are some of the reasons listed for why female may prefer more brightly colored males.

10. How did sexual selection influence coloration. Give data from one the trials to support this conclusion (be sure to include predator conditions for trial in your discussion).


11. The reading states that “male guppies live in a crossfire between their enemies and their would be mates”. Explain what this statement means.

12. Explain how this activity illustrates that adaptations are often compromises.

13. Why do you think John Endler observed different patterns of coloration in different areas of the stream.

14. What do you think would happen over time if mostly drab guppies were placed in a stream that had no large predators?

15. What do you think would happen over time if mostly bright guppies were placed in a stream that had many large predators.


16. Why do you think guppies in different areas of the stream have different coloration?