Question

imagine you are a scientist observing a wild population of rats. you study the population for many years. your focus is counting how many individuals have each of the pictured variations.

variation 1

variation 2

as the individuals in this population reproduce, those with variation 1 slowly begin to outnumber those with variation 2.

using what you know about natural selection, explain in 2 or more sentences why variation 1 is becoming more common. you may talk more generally or you may make specific guesses about the population’s environment.

1 pt - give a reason why variation 1 is increasing.

1 pt - use natural selection to support your stated reason.

(2 points)

Explanation:

Variation 1 (white rats) is increasing because their color likely provides a survival advantage in their environment, such as camouflage in a light - colored habitat (e.g., a snowy or light - colored rocky area). According to natural selection, organisms with traits that enhance their survival and reproduction (like better camouflage to avoid predators) are more likely to pass on their genes. So, white rats are more likely to survive long enough to reproduce, leading to more offspring with the white - colored variation, thus increasing the frequency of variation 1.

Answer:

Variation 1 is increasing because its trait (e.g., white color) gives individuals a survival advantage (like camouflage in a light - colored environment) over those with variation 2. By natural selection, organisms with advantageous traits are more likely to survive, reproduce, and pass on their genes, so the number of rats with variation 1 grows as they produce more offspring with this trait.