Download Peppered Moth Simulation

Name:______________________
Peppered Moth Simulation
Go to: http://www.biologycorner.com/worksheets/pepperedmoth.html
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 in demonstrating the
theory, however, 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, which might have helped to
persuade people of his theory, were in the countryside of his native England. One
such example is the evolution of the peppered moth Biston betularia.
The economic changes known as the industrial revolution began in the middle
of the eighteenth century. Since then, tons of soot has 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
moth in England have undergone a change from light to dark. Similar observations
have been made in other industrial nations, including the United States.
Instructions:
You will run two simulations for 5 minutes each, during this time you will play the
part of a blue jay that eats moths.
On the left side of the screen, scroll down. Before you begin, make sure to turn the
volume OFF.
Click on Run Lichen (light colored) forest. You are going to “eat” moths both dark and
light colored. To “eat” moths click on as many moths as you see. Hint: To “eat” them
make sure the crossbar (+) at the beak of the blue jay is on the moth you are clicking
on. Set your stop watch for 5 minutes. When you are ready, start your stop watch and
“eat” moths for 5 minutes. After 5 minutes record the % of dark moths and light
moths on the data table on the back of this sheet.
Click on Run Soot (dark colored) forest. You are going to “eat” moths both dark and
light colored. To “eat” moths click on as many moths as you see. Hint: To “eat” them
make sure the crossbar (+) at the beak of the blue jay is on the moth you are clicking
on. Set your stop watch for 5 minutes. When you are ready, start your stop watch and
“eat” moths for 5 minutes. After 5 minutes record the % of dark moths and light
moths on the data table on the back of this sheet.
Analysis - answer all questions on the back of this paper.
Name:______________________
Peppered Moth Analysis
1. Data Table
Percent Dark Moths
Percent Light Moths
Lichen Forest
Sooty Forest
2. Explain how the color of moths increases or decreases their chances of survival
depending on the environment.
3. 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 number
of each type of moth that would be captured.
4. 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.)
5.
What underlying law of nature has produced this change? (Use Darwin's theory
of evolution and apply it to what you have learned in this investigation.)