Download Natural Selection in Black and White

NAME _________________________________________________________ DATE _________ PERIOD _______________________________
Peppered Moth Simulation:
Natural Selection in Black and White
http://www.techapps.net/interactives/pepperMoths.swf
Peppered Moths: Natural Selection in Black and White
Select Peppered Moth simulation from Mrs. Lamers’ listing on The Destiny Website
BACKGROUND
Read the following sections and answer the questions below. The titles correspond to the tag for the circles
I. The Life Cycle of the Peppered moth
1. Where are peppered moths commonly found? _____________________________________________
2. Who are their natural predators?
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3. When are moths most active? Why? ______________________________________________________
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4. Describe the adult peppered Moth’s camouflage. Be specific. _________________________________
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5. How do the larvae (caterpillar form) avoid detection? ________________________________________
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6. What does the typical peppered moth look like? ____________________________________________
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7. What is the dark, almost black moth called? ________________________________________________
8. What name is given to the peppered moth with a greater number of black spots? _________________
9. Up until 150 years ago, which type of peppered moth was most common? _______________________
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II. Pollution and Peppered moths
10. What is the scientific name of the peppered moth? __________________________________________
11. When did the first recorded sighting of a dark peppered moth take place? _______________________
12. How did the peppered moth population in England change by 1900? ____________________________
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13. What was happening at the time which favored the survival of dark colored moths? Explain.
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How were genetics involved in the color of the moths?
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14. What is natural selection?
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Name_______________________________ Date _________ Period ______
Peppered Moth Simulation
Objective: Simulate changes in moth population due to pollution and predation, and observe how species can
change over time.
Introduction:
Charles Darwin accumulated a tremendous collection of facts to support the theory of evolution by natural
selection. One of his difficulties was the lack of an example of evolution over a short period of time, which
could be observed as it was taking place in nature. Although Darwin was unaware of it, remarkable examples
of evolution were in the countryside of his native England. One such example is the evolution of the peppered
moth Biston betularia.
The industrial revolution began in the middle of the eighteenth century. Since then, tons of soot have been
deposited on the country side around industrial areas. The soot discolored and generally darkened the
surfaces of trees and rocks. In 1848, a dark-colored moth was first recorded. Today, in some areas, 90% or
more of the-peppered moths are dark in color. More than 70 species of moths in England have undergone a
change from light to dark. Similar observations have been made in other industrial nations, including the
United States.
III. A Bird’s Eye view of Natural selection (circle with bird and moths)
Instructions:
You will each simulations three times, during this time you will play the part of a blue jay that eats moths.
After each trial, record the percentage of dark moths and light moths in the table below (“light colored” lichen
forest and the dark colored “sooty forest”)
Peppered Moth Analysis
Data Table
Forest
Percent Light Moths
Light Forest: Trial 1
Light Forest: Trial 2
Light Forest: Trial 3
Average population in Light (lichen)
forest (ave. of trials 1-3)
Dark Forest: Trial 4
Dark Forest: Trial 5
Dark Forest: Trial 6
Average population in Dark (sooty)
forest (ave. of trials 4-6)
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Percent Dark Moths
Analysis:
Average the percent of moths of each color for each forest and record the values in the table.
To average the values, find the sum of the Percent of Light colored moths in the Light forest for all
three trials.
Then divide that sum by 3 (the number of trials).
Repeat using the values for dark colored moths in the Light forest, light moths in the dark forest and
dark moths in the dark forest.
Create two pie charts, one for each forest.
Use your data to show the moth populations in each.
Be sure to include the percentages.
Remember, an entire “pie” is 100 %.
Light forest
Dark Forest
15. What did the experiment show about how prey is selected by predators?
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16. What moth coloration is the best adaptation for a dark background? How do you know?
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17. Explain how the color of moths increases or decreases their chances of survival depending on the
environment.
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18. 500 light colored moths and 500 dark colored moths are released into a polluted forest. After 2 days
the moths were recaptured, make a prediction about the amount of each type of moth that would be
captured. (Hint: if they are not recaptured, assume that they have been eaten.) Use your prior
experiment to help form your prediction.
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19. How has the striking change in coloration come about? (Include an explanation of how the dark moth
appeared and how the proportion of dark moths changed from 0.0005% to more than 90% in polluted
forests.)
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20. How does the simulation model natural selection?
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Problem:
Examine the table and construct a graph. Plot the years of the study on the X-axis, and the number of moths
captured on the Y axis. You should have 2 lines on your graph - one for light moths, and one for dark moths.
# of Light # of Dark
Year Moths
Moths
Captured Captured
2
537
112
3
484
198
4
392
210
5
246
281
6
225
337
7
193
412
8
147
503
9
84
550
10
56
599
21. Explain in your own words what the graph shows.
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22. Describe another situation where this type of selection might occur.
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