Download The Peppered Moth

Name________________________Per_____
The Peppered Moth
Natural selection is the reproductive success of organisms that are best suited for an
environment. It is the driving force of evolution. Natural selection occurs within populations, which are
interbreeding groups of individuals of the same species. Genetic variation is one factor that influences
natural selection. Genetic variation occurs when a population has multiple versions of a trait. For
example, some organisms in a population of moths are dark colored, while some are light colored. Natural
selection over time results in adaptations, where certain traits are favored due to their influence on
survival. Adaptations over many generations can lead to evolution. Peppered moths have lived in the
forests around Manchester, England for hundreds of years. There are two genetic variations for color in
peppered moths- the moths can be dark with light spots OR light with dark spots.
Before the 1800s the trees were light colored and the light colored moths were well camouflaged. After
the 1800s, when England went through the Industrial Revolution, the pollution from factories made the
trees darken. Now, the trees were dark colored and the dark colored moths were well camouflaged.
Various birds eat both kinds of moths IF they are able to be seen.
PART I: Peppered Moth Simulation Procedure
1. http://www.techapps.net/interactives/pepperMoths.swf
2. Click on each circle starting at the left to read about the peppered moth
3. Finally, run the simulation by clicking on the circle with the picture of the bird and moths
4. Click on the left circle (light forest before the Industrial Revolution) first
5. Hunt for moths for 60 seconds and then record the percentage of remaining moths of each type below.
6. Click on the circle with the bird to return to the main menu
7. This time, click on the dark forest circle on the right and repeat step 5.
Forest Detail:
% Dark Moths Remaining After Hunt
% Light Moths Remaining After Hunt
Light Forest (Before Industrial
Revolution)
Dark Forest (After Industrial
Revolution: soot-covered trees)
PART II: LABEL THE PICTURES:
1. Label each tree as Before Industrial Revolution
OR After Industrial Revolution
2. Draw one arrow
on each tree pointing
to the moth type that would be most easily
seen, and therefore eaten, by predator birds.
label: _____________
label: _______________
Peppered Moth Populations
Data: The table below displays the Number
of peppered moths of each color found over
a ten year period. Graph the data below to
show how the peppered moth populations
changed in the 1800s. You should make a
line graph with two lines. Years should be on
the x axis and number of moths on the y
axis. Assume year one was the start of the
industrial revolution. Don’t forget a legend.
Year
1
2
3
4
5
6
7
8
9
10
503
484
392
246
225
193
147
84
53
38
Dark Colored
Population
112
198
210
281
357
412
503
594
638
673
Moth Population
PART III: Line Graph of Data:
Light Colored Population
Time (years)
Key : (color circles)
Light Colored Moths
Dark Colored Moths
Analysis Questions:
1. The moths exhibited genetic variation. What were the two types of moths?
_______________________________ & ____________________________
2. What changes occurred in both forms of the moth over these ten years? (see graph above)
______________________________________________________________________
______________________________________________________________________
3. What adaptation did the dark moths have after the Industrial Revolution that increased their survival
rate? _______________________________________________________________________
4. Critical Thinking: England has recently cleaned up their factories and now produces much less pollution.
As a result, the trees are slowly becoming lighter. What might happen to the populations of each form
of the moth in the next 10 years? Why?___________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________