Download Peppered Moth Simulation Lab

Name _______________________________________
Date _______________
Period _____________
Lab #__________-Peppered Moth Simulation Lab
Purpose: In this lab, you will simulate how predators locate prey in different
environments. You will analyze how color affects an organism's ability to survive
in certain environments.
Background: 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. In1848, 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.
Industrial Melanism is a term used to describe the adaptation of a population in response to pollution.
One example of rapid industrial melanism occurred in populations of peppered moths in the area of
Manchester, England from 1845 to 1890. Before the industrial revolution, the trunks of the trees in the
forest around Manchester were light grayish-green due to the presence of lichens. Most of the peppered
moths in the area were light colored with dark spots. As the industrial revolution progressed, the tree
trunks became covered with soot and turned dark. Over a period of 45 years, the dark variety of the
peppered moth became more common.
Procedure:
1. Type the following website into the browser bar
http://www.techapps.net/interactives/pepperMoths.swf
2. Scroll over each of the icons and select the icon with the title A BIRDS EYE VIEW OF NATURAL
SELECTION.
3. Read the introduction about natural selection and then click onto to the next screen. Choose a
forest to run a simulation. First choose the light forest and then choose the dark forest.
4. Run both simulations, and record data in the table. You should be recording the percentage of
each population after a season of predation.
5. Answer analysis questions.
Data Collection:
Light Forest
Light Moth
Population
Dark Moth
Population
Analysis (answer all questions in complete sentences)
Dark Forest
1. In each simulation, what was the original percentage of each colored moth in the population?
2. What is Industrial Melanism?
3. What did the experiment show about how prey are selected by predators?
4. Which moth is best adapted for the dark color forest?_____________________
Why?
5. Which moth is best adapted for the light color forest?_____________________
Why?
6. In a changing environment is the frequency of dark moths to light moths going to remain the same?
Explain.
7. How does this simulation model natural selection?
8. Cryptic coloration is an adaptation that helps an organism blend into and hide in its environment. If
moths that are cryptically colored survive predators better when they are not moving, why do they
move?
9. What is likely to happen to the size of the blue jay population as more of the moth population
becomes cryptically colored?