Environmental Science Exam Student\'s Name 32. Student Number H. B. D. Kettlewel
ID: 271476 • Letter: E
Question
Environmental Science Exam Student's Name 32. Student Number H. B. D. Kettlewell observed that peppered moths in the forests of England were becoming darker in color over time. In addition, he observed that pollution had turned the tree trunks black. He thought it would be easy for birds to spot and capture light-colored moths resting on the black tree trunks and that this would result in light moths being eaten more often than dark moths. A. State, in the form of a hypothesis, Kettlewell's explanation as to why a great proportion of the moths were dark. The great proportion of the moths are dark because B. Kettlewell tested his idea that moths who did not match the color of the tree trunks would be more obvious to predators. He placed light moths on dark tree trunks and observed how many of them were eaten by birds. Then he placed the same number of dark moths on dark tree trunks and observed how many were eaten by birds. What was the variable in this experiment? C. Imagine that Kettlewell released 50 light moths onto dark tree trunks and 30 were eaten. He released 50 dark moths onto dark tree trunks and 10 were eaten. Would these results uphold or discredit his hypothesis? Why? (over) 41Explanation / Answer
A) The great proportion of moths were black because, in the polluted environment the black colour gave the moths a reproductive advantage over the light coloured ones as they would be easily spotted and eaten by predators. Thus black moth were able to leave more number of viable progenies and in time their number got increased.
B) The number of moths eaten is the variable in this experiment. The same number of dark and white moths were used and assuming that the predator visits the tree regularly, the variable is the number of moths of each colour eaten by the predators.
C) It woulduphold his hypothesis. It shows about 60 % of total light moths were spotted and eaten and only 20% of dark moths were eaten. Since the colour is the only difference between two types, it upholds his hypothesis that dark moths are less eaten by predators.
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