Download Sex and the Single Guppy (taken from http://www

NATS 104
Sex and the Single Guppy Homework 1 (5 points) Due in your lab section next week, Jan
27-29 (assignment adapted from http://www.biologycorner.com/worksheets/sex-selection.html)
Name:___________________________
STEP ONE: Start by going to the “sex and the single guppy” website:
http://www.pbs.org/wgbh/evolution/sex/guppy/
Introduction
First of all, familiarize yourself with the site:
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View the guppy gallery
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View the predator gallery
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Read about John Endler's experiment
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Read the three possible hypotheses for guppy coloration
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Practice doing a simulation:
Select "To start, choose how you want to set up your simulation pool."
Choose guppy color types and predator species number.
Click on "Run".
Stop after a few generations.
“View results" and “read summary”.
Answer the following questions:
1) What is the scientific name of the guppy?_______________________
2) Why was the guppy introduced in many parts of the world?_______________
3) What is a predator on guppies in the wild?____________________
4) Do two simulations for at least 5 generations each, and read the results. Write which factors
you chose for one of the simulations below. Be prepared to discuss your findings in lab.
Guppy color type:________________
Predator species and number:__________________
Number of generations simulation was run:____________
Beginning frequencies of males color types:
Brightest:_________ Bright:_______
Drab:_________ Drabbest:________
Ending frequencies of males color types:
Brightest:_________ Bright:_______
Drab:_________ Drabbest:________
5) Write a brief answer to this question, based on reading the website and the simulations you ran:
To what degree do predation and sexual selection affect guppy coloration? (Which has a greater
effect, or do they work equally to influence guppy populations?)
6) We will be using feeder guppies from a pet store for our experiments. They were collected in
the wild, but have been raised in pet stores for many generations as food for larger fish. What do
you think that these conditions (in pet stores) might favor, bright or dull males, and why?