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APES Lab: Flashy Fish
Purpose: The purpose of this activity is to analyze how guppy populations change over time. The simulation activity allows you to start with a pool of guppies and your choice of predators. You will be able to watch what happens to your guppy population and how the introduction of predators can affect the guppy's appearance. The simulation will help you understand what pressures drive guppy evolution.
Background: Professor John Endler traveled to Trinidad in the 1970s to study wild guppies. The guppies live in small streams that flow down the mountains from pool to pool. In this activity, you will take part in an online simulation of Endler's work. You will collect data, formulate a hypothesis, and run a series of experiments. You will find out about the interplay between natural selection and sexual selection in this wild population of guppies.
Define: natural selection -
sexual selection –
population –
Procedure:
1. Open up the guppy sex simulator by typing the following web address:
http://www.pbs.org/wgbh/evolution/sex/guppy/ed_pop.html
2. If being flashy and colorful attracts predators, why do you think guppies are so colorful?
3. After viewing the guppy gallery, pick the fish you find most interesting. What is the fish’s scientific name, origin and average size? Describe the coloration of the fish you chose.
4. After viewing the predator gallery, pick the fish you find most interesting. What is the fish’s common name, scientific name, and origin?
5. View the guppy’s habitats. What habitat conditions would affect the predator populations?
Endler’s Discovery and Variations of Guppy’s in Pools
6. Who is John Endler? What did he study and where did he study it?
7. For each of the three stream areas, describe the guppy coloration:Pool 1:Pool 2:Pool 3:8. 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)
Guppy Simulation
In this part of the project, you will run 5 experiments and collect data about guppy populations. This data will then be analyzed to determine whether your hypothesis was correct or not. Make sure each simulation runs through at least 5 generations.9. Trial 1Guppy Color Types ___________________________________Predator Species and Numbers _________________________Results and Analysis:Percentage of Brightest Guppies after 5 generations ______Percentage of Bright Guppies after 5 generations ________Percentage of Drab Guppies after 5 generations _________Percentage of Drabbest Guppies after 5 generations ________Analysis of the data: (What happened in this simulation, did the guppy coloration change over time? Did the predators seem to affect guppy Coloration? )
10. Trial 2Guppy Color Types ___________________________________Predator Species and Numbers _________________________Results and Analysis:Percentage of Brightest Guppies after 5 generations ______Percentage of Bright Guppies after 5 generations ________Percentage of Drab Guppies after 5 generations _________Percentage of Drabbest Guppies after 5 generations ________Analysis of the data: (What happened in this simulation, did the guppy coloration change over time? Did the predators seem to affect guppy Coloration? )
11. Trial 3Guppy Color Types ___________________________________Predator Species and Numbers _________________________Results and Analysis:Percentage of Brightest Guppies after 5 generations ______Percentage of Bright Guppies after 5 generations ________Percentage of Drab Guppies after 5 generations _________Percentage of Drabbest Guppies after 5 generations ________Analysis of the data: (What happened in this simulation, did the guppy coloration change over time? Did the predators seem to affect guppy Coloration? )
12. Trial 4Guppy Color Types ___________________________________Predator Species and Numbers _________________________Results and Analysis:Percentage of Brightest Guppies after 5 generations ______Percentage of Bright Guppies after 5 generations ________Percentage of Drab Guppies after 5 generations _________Percentage of Drabbest Guppies after 5 generations ________Analysis of the data: (What happened in this simulation, did the guppy coloration change over time? Did the predators seem to affect guppy Coloration? )
13. Trial 5Guppy Color Types ___________________________________Predator Species and Numbers _________________________Results and Analysis:Percentage of Brightest Guppies after 5 generations ______Percentage of Bright Guppies after 5 generations ________Percentage of Drab Guppies after 5 generations _________Percentage of Drabbest Guppies after 5 generations ________Analysis of the data: (What happened in this simulation, did the guppy coloration change over time? Did the predators seem to affect guppy Coloration? )
Summary
14. Describe how predators influence guppy coloration.
15. Was your hypothesis correct, use your data to justify your answer.
16. What does it mean that “male guppies live in a crossfire between their enemies and their would-be mates?”
17. Why do you think guppies in different areas of the stream have different coloration?
18. How does the number of predators affect the number of brightly colored guppies?
More about Sexual Selection
Read the article in Scientific American titled: “How Females Choose Their Mates”http://www.freerepublic.com/focus/news/646047/posts
1. Why might females be choosier when picking a mate, as opposed to males?
2. Summarize Darwin’s hypothesis on how showy or flamboyant traits might have evolved.
3. How do female grouse choose a mate?
4. Describe the “handicap principle.”
5. What is runaway selection?
6. Describe the scientific method involved in Dugatkin’s experiment to determine whether genetic predisposition or imitation plays a greater role in guppy mate selection.
