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