In mice, fur color is a genetically determined trait. To observe the effects of natural selection on fur color in mice, scientists set up six enclosures with either light- or dark-colored sand on the ground. The enclosures were isolated from all ground predators and wild mice but accessible to predatory birds. The scientists placed equal numbers of light- and dark-colored mice into each enclosure. A total of 500 mice were used in the experiment. After several generations, the scientists sampled the mice and found that populations in the light sand enclosures were, on average, lighter in color than the original population, while those in the dark sand enclosures were, on average, darker in color than the mice in the original population.

a) describe the way the scientists will determine the evolutionary fitness of the mice in the experiment.

b) Identify the independent variable in the scientists’ experiment.

c) State the null hypothesis

d) The scientists claim that the changes in the frequency of fur color were the result of natural selection. Justify their prediction.