BIOL 101 The Peppered Moth Name

Due May 3/4 Period

There are two forms of the peppered moth (Biston betularia) in England- a dark-colored form(carbonaria) and a light form (typica). Moths rest on tree trunks and branches with their wingsopen.

In the early 1800's, most moths were the light form. The first dark form was reported in 1848.The dark form increased in frequency during the last half of the 1800s. By 1895, 98% of thepeppered moths in Manchester were the dark form.

The increase in the dark (carbonaria) form of the moth occurred at a time of rapidindustrialization in England- the industrial revolution. During this time, an increase in theamount of coal-burning factories caused widespread pollution. The pollution killed light-coloredlichens causing the tree bark to appear darker. The trees in polluted areas were also covered withdark soot.

In 1896, J. W. Tutt proposed that bird predation was responsible for the increase in abundance ofthe dark form of the moth. He reasoned that birds had difficulty seeing the dark form on the darktrees; the dark moths were camouflaged. Therefore, the dark moths survived and reproducedbetter than the light forms, hi clean areas, the trees were covered with lichens, making the paleform more difficult for birds to see. In the early 18QOs, the tree trunks were light and the lightforms of the moths were more difficult for the birds to see.

To test the bird predation hypothesis, H.B.D. Kettlewell released moths of each type and thenmeasured the number that were later recaptured. The experiment was performed in a pollutedarea in Birmingham, England and in a clean area in Dorset. The moths were marked with a dot ofpaint so that he could identify them after they were released and then recaptured. In theunpolluted area, he recaptured 13.7% light, 4.7% dark indicating that the light form survivedbetter. In the polluted area, he recaptured 13% light and 27.5% dark suggesting that the darkform survived better.

These results support the hypothesis that color change was due to bird predation. Birds atemoths that were easiest to find based on the relative color of the moth and the trees on whichthey rested.

1. Underline the words that first describe the evolution of moths in Manchester (underlineone sentence or less).

2. Is this macroevolution or microevolution?

3. Circle the words that describe natural selection of moths in Manchester (circle onesentence or less).

4. Identify the adaptation of the moths in Birmingham that was important in thisevolutionary event with an arrow.

5. Are the dark Manchester moths an example of directional selection, stabilizing selectionor diversifying selection?

6. What did Kettlewell use as a control group for his experiment?

7. What is the genus of the light peppered moth?

8 Is there evidence that the light and dark peppered moths are now different species?

9. Kettlewell presumed that the moths in Birmingham and Dorset were reproductivelyisolated. This implies that these groups of moths were in different .

10. Did their geography provide a pre-fertilization or post-fertilization barrier?

Was the barrier spatial, behavioral, mechanical, temporal, gametic, or due to

hybridization?