Question

Lab: Darwin’s Theory of Natural Selection in Action: Peppered Moth Simulation

Purpose:

To describe the importance of coloration in avoiding predation

To relate environmental change to changes in organisms

To explain how natural selection causes populations to change

Background:

                Industrial melanism is a term used to describe that 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 (chimney smoke) and turned dark. Over a period of 45 years, the dark variety of the peppered moth became more common.

Materials:

2 sheets of white paper

2 sheets of any colored paper

Tweezers

Scissors

Clock with a second hand

Hypothesis: (remember that a hypothesis is a testable statement)

If the color of the prey matches the background color than (complete the statement)______

____________________________________________________________________________.

Procedure:

1. Using one of your sheets of colored and one of your sheets of white paper, cut out 20 squares of each (20 colored and 20 white). There is a square at the top of this page that shows you the size of the square to use.
2. Place a sheet of white paper on the table and irregularly arrange 20 white cutouts and 20 colored cutouts over the surface.
3. Use forceps to pick up as many of the cutouts as you can in 15 seconds. Eating is simulated by picking up the cutouts with forceps and placing them on the countertop in front of you. Imagine yourself as a “predator” in the wild.
4. This trial will be repeated. Next place the cutouts on the colored background. Record the data on the next page. You will have a total of four trials: two with the colored paper background and two with the white paper background

Data Table:

Trial #	Background	Starting Population of white cutouts	Starting population of colored cutouts	Number remaining of white cutouts	Number remaining of colored cutouts
1	White	20	20
2	White	20	20
3	colored	20	20
4	colored	20	20

Analysis:

1. What did the experiment show about how predators select their prey? Did your experiment support your hypothesis?

2. If the cutouts represented moths, what moth coloration is best adapted for a dark (colored) background? How do you know?

3. What would you expect the next generation of moths to look like after trial 1? What about the next generation after trial 3?

4. Did the experiment work in the way it was supposed to? Why/why not?

Conclusion:

Write a 5 sentence summary of a) what the experiment tested and showed b) how the experiment relates to natural selection c)how the experiment is an example of evolution (gradual change). Use the space below:

Answer 1

Hypothesis: If the color of the prey matches the background, it becomes more likely to avoid predation.

There are a few critical points in experimenting. First of all, the vision of the predator is highly crucial to the experimental results.

Conclusion: a. The theory of natural selection is tested. The experiment tested prey and predator relationship; it tests the predation of prey against its natural habitat. It shows that the prey adapted to natural habitat will have higher chances of survival.

b. When there is a shift in the natural habitat, the predator is likely to eat the prey that are unable to adapt to change in the color of the environment. There are more number of individuals who are adapted to the environment showing natural selction theory

c. The experiment is a good example of evolution is affirmed by the fact that natural selection favors the chances of survival of prey, which would be directly linked to an increase in their population.