In mice, fur color is a genetically determined trait. To observe the effects of natural selection on fur color in mice, scientis

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In mice, fur color is a genetically determined trait. To observe the effects of natural selection on fur color in mice, scientis

ts 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.

Biology

2 answers:

Tresset [2.2K] · Answer 1 · 2026-02-17T02:50:20+03:00

Answer/Explanation:

A. The evolutionary fitness of a species represents its capability to reproduce and survive, contributing its genes significantly to the gene pool in subsequent generations.

The scientists can compute the evolutionary fitness of the mice in their study by assessing the relative survival and reproduction rates of each genotype present in the mice. Essentially, it is the survival and/or reproduction rate of each genotype divided by the maximum rate among the genotypes in the population. Alternatively, they may also simply calculate the relative fitness of each phenotype observed in the mice.

B. The independent variable in this experiment is the variable being altered to observe its effect on the dependent variable. The different environments serve as the independent variable affecting fur color.

C. The proposed null hypothesis may state:

Natural selection does not influence the fur color in mice.

Or

There is no impact of environmental variation on mice fur color.

D. Changes in allele frequencies concerning fur color, as evidenced in the experiment, largely stem from natural selection. This phenomenon is described as diversifying selection, where mice that blend with their environment are prioritized over those with intermediate characteristics. Individuals that struggle to camouflage are more likely to fall prey to birds, reducing the numbers of those who do not exhibit extreme colorations.

The scientists' assertions are supported by the observation that fur color frequencies will adjust over time as a result of natural selection processes.

vlada-n [2.5K] · Answer 2 · 2026-02-17T02:50:20+03:00

The correct answers to these questions are as follows:

1) By examining enclosures with various colors on the ground, which may enhance or obstruct the populations' success.

2) Independent variable: amount of generations.

3) Null hypothesis: different colors do not influence the fitness of the populations.

4) This is a result of directional selection. Directional selection is a form of natural selection where the prevalence of a trait is modified to favor one phenotype in reaction to environmental changes.