Peppered Moth Survey Lab
Problem: What is the relationship between environmental changes and the color variation of the
peppered moth?
Introduction:
Industrial melanism is the term used to describe the adaptation of darkening by an
organism in response to industrial pollution. One example of rapid industrial melanism occurred
n the peppered moth, Biston betularia, in the area of Manchester , England from 1845 to 1890.
Before the Industrial Revolution, the trees in the forest around Manchester were light
grayish-green due to the presence of lichens on their trunks. Peppered moths, which lived in the
area, were light-colored with dark spots. Their coloring served as camouflage against predators,
especially birds. As the industrial revolution progressed, the trees became covered with soot,
which turned the trunks dark. Over a period of 45 years, a change took place in the peppered
moth population in this area.
TABLE A: Analyzing Predator-Prey Relationships
Year
2
3
4
5
6
7
8
9
10
Number of Light
Moths Captured
537
484
392
246
225
193
147
84
56
Number of Dark
Moths Captured
112
198
210
281
357
412
503
594
638
Table A represents data from a 10 year study of two varieties of the same species of peppered
moths. The numbers represent moths captured in traps for 10 consecutive years. The traps were
located in the same area each year.
1. Using the data provided in Table A, construct a graph comparing the numbers of each
variety of peppered moth. Label the axes with the years of the study (plotted horizontally) and
the number of moths captured (plotted vertically). Use different colored pencils or a solid line
and a dashed line to indicate the two color variations. Be sure to include a key beneath the
graph
1. What preys on the peppered moth?
Birds
2. If the bark of trees is dark and the moths that rest there are light-colored, what will most
likely happen to the moths?
The light-colored moths will be easily spotted and eaten
3. What is a mutation?
A "Change" in a DNA Sequence.
4. What could have caused the first dark-colored moths to occur?
A gene Mutation.
5. What caused the tree trunks of many trees in England to turn from a light color to a dark
color?
The Industrial Revolution.
6. Which variety of moth increased over the 10-year period?
The number of Dark Colored Moths.
7. What is the name of this type of evolutionary change? (Hint- read the 1st paragraph of the
introduction)
Industrial Melanism
8. Assume that you are selecting from a field of an equal number of light and dark “prey”.
You would expect to pick up an approximately equal number of each type, if coloration is
not important to predation success. What did your experiment indicate?
9. Using the data on the graph, draw a conclusion concerning the population of peppered
moths in the sampled area of England.
As the pollution increased the number of light colored moths decreased.
10. Explain the reason for the increase in the number of dark colored moths.
The industrial revolution caused the tree trunks to darken. Making them easier to hide from predators.
11. What means could be used to return the environment of the peppered moth to its original
state?
We could reduce pollution.
12. What effect would cleaning up the environment have on these moths?
There would increase in light colored moths and a decrease in dark colored moths.