Peppered Moths

Kettlewell also wanted to find evidence that wild birds ate peppered moths. He also wanted to show that wild birds would eat more white moths on polluted trees. Kettlewell set up an experiment to see if this was true.

Kettlewell collected equal numbers of white and dark peppered moths. He went to a non-polluted forest and set up a blind to hide from the birds. He stuck these dead white and dark moths on trees beside his blind. He watched to see if the birds ate more white or dark moths. He repeated this experiment in a polluted forest. This is his data:

	white moths eaten by birds	dark moths eaten by birds
in non-polluted forest	26	164
polluted forest	43	15

In a non-polluted forest Kettlewell expected more dark moths to be eaten. Does his data support that prediction?

In a polluted forest Kettlewell expected more white moths to be eaten. Does his data support that prediction?

Kettlewell place the moths on tree trunks where they were easy for him to observe. Some scientists criticized this choice of location. Kettlewell didn't provide evidence that peppered moths spent the day on tree trunks. The criticizing scientists didn't know where moths hide. The scientists thought that moths might hide under branch or places where their camouflage wasn't important.

A scientist named, M. E. N. Majerus spent 40 years looking for and studying peppered moths. During his 40 years of searching the woods of England for peppered moths he found only 47 moths in the wild. That is a little over one each year. The following table shows where he found them.

moths found in the wild
	moths	percent
exposed trunk	6	12.8%
unexposed trunk	6	12.8%
trunk/branch junction	20	42.6%%
branches	15	31.9%

The most common resting place for a peppered moth was the trunk/branch junction. This is on the trunk and a few inches under a branch. What percentage of wild moths were found resting on tree trunks?

As a scientist do you feel that this data supports Kettlewell's experiment of placing moths on tree trunks? Does the data cause you to totally support the theory of natural selection as the cause for the increase in dark moths? Does the data cause you to totally reject the theory? Does the data provide a little more support for the theory? Does the data provide a little more evidence against the theory?

3. Mutation
2. Background
1. Introduction

5. Recapture