How Natural Selection Works

Question 1

In a forest where tree bark is primarily brown, a population of beetles shows two color variations: green and brown. Birds that hunt in this forest rely on sight to find beetles. Which explanation best describes how the genetic variation in beetle coloration affects the probability of survival and reproduction in this environment?

Accepted Answer

Beetles with brown coloration are less visible on the bark, so they are less likely to be eaten, survive longer, and produce more offspring, causing the brown coloration gene to become more common.

Answer

All beetles, regardless of color, have the same chance of being eaten because birds eat randomly, so coloration does not affect survival.

Answer

Green beetles can change their color to brown when predators are nearby, allowing them to avoid being eaten.

Answer

The forest environment will eventually turn green to match the beetles, making green beetles less visible and increasing their survival.

Question 2

A population of moths is studied over three generations. The percentage of moths with a dark wing pattern is recorded as follows: Generation 1: 30% Generation 2: 45% Generation 3: 60% Which statement best describes the change in the frequency of the dark wing pattern over these generations?

Accepted Answer

The frequency of the dark wing pattern increased.

Answer

The frequency of the dark wing pattern first increased then decreased.

Answer

The frequency of the dark wing pattern stayed the same.

Answer

The frequency of the dark wing pattern decreased.

Question 3

A scientist records the number of moths with light-colored wings and dark-colored wings in a population over three generations. The data are shown in the table: Generation 1: Light 40, Dark 60 (total 100) Generation 2: Light 55, Dark 45 (total 100) Generation 3: Light 70, Dark 30 (total 100) Which statement correctly describes the change in the frequency of the light‑wing trait from Generation 1 to Generation 3?

Accepted Answer

The frequency of the light‑wing trait increased from 0.40 to 0.70.

Answer

The frequency of the light‑wing trait stayed the same at 0.50.

Answer

The frequency of the light‑wing trait decreased from 0.40 to 0.30.

Answer

The frequency of the light‑wing trait increased from 0.40 to 0.55.

Try three questions

A population of moths is studied over three generations. The percentage of moths with a dark wing pattern is recorded as follows: Generation 1: 30% Generation 2: 45% Generation 3: 60% Which statement best describes the change in the frequency of the dark wing pattern over these generations?

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