Correct! The rock pocket mice that Dr. Nachman catches in the film have a mutation in a gene that leads to the dark fur color. Select another correct answer. You selected all the correct answers.

The dark rock environment doesn’t cause dark-colored rock pocket mice to appear. The environment provides an advantage to them, and their dark progeny, once they arise. Try again.

Individual rock pocket mice cannot change their fur color to camouflage themselves. Recall that genes encode traits. Try again.

Predation doesn’t cause dark-colored rock pocket mice to appear. Predation selects against light-colored mice, causing dark-colored mice to increase in the population. Try again.

Correct! The color of a rock pocket mouse’s belly is not visible to a predator and therefore is not under strong selection pressure. There is no selection for either dark- or light-colored bellies. Select another correct answer. You selected all the correct answers.

There is no reason to assume that mutations causing dark bellies have not occurred. However, without selection, the dark-belly trait has not become common. Try again.

If there were a reproductive advantage to having a dark belly, you would expect to see mice with dark bellies. All dark-colored mice have white bellies. Try again.

A white belly, if visible, would be a disadvantage on a dark lava flow. But since a rock pocket mouse’s belly is rarely exposed, it is not a factor in the animal’s ability to avoid predation. Try again.

Whether a mutation is favored, neutral, or detrimental depends on the conditions the organism lives in. Try again.

Whether a mutation is favored, neutral, or detrimental depends on the conditions the organism lives in. Try again.

Whether a mutation is favored, neutral, or detrimental depends on the conditions the organism lives in. Try again.

Correct! Mutations are rare genetic changes that can be neutral, beneficial, or detrimental depending on an individual’s circumstances. A mutation that causes dark-colored fur is good for a rock pocket mouse living on black lava and bad for one living in the sandy desert. Select another correct answer. You selected all the correct answers.

Dark-colored rock pocket mice have a reproductive advantage, so they would have more offspring than light-colored mice. Try again.

Correct! A small evolutionary advantage can lead to large changes in a population. The larger the advantage, the faster the changes occur. Select another correct answer. You selected all the correct answers.

A competitive advantage of 5% would lead to 95% of this population becoming dark in less than 1000 years. Try again.

A more advantageous mutation (10%) would lead to 95% of this population becoming dark in about 100 years. Try again.

Mutations occur at random independently of the environment. Try again.

Correct! On dark lava flows, natural selection favors mice with mutations for dark-colored fur and not mice with light-colored fur. Select another correct answer. You selected all the correct answers.

Correct! On dark lava flows, natural selection favors dark-colored mice and on light sand it favors light-colored mice. Select another correct answer. You selected all the correct answers.

Correct! Natural selection can shape populations depending on which mutations and traits are passed on from one generation to the next. Select another correct answer. You selected all the correct answers.

If the mice had the same mutation, it would imply a single evolution of dark color. Instead, Nachman describes evolution occurring “again and again” on the lava flows. Try again.

Correct! Two different mutations giving rise to dark-colored fur have been found in two genes, which means that both genes are involved in fur color. Select another correct answer. You selected all the correct answers.

Correct! Since each population has a different mutation, the two mutations must have occurred independently. Select another correct answer. You selected all the correct answers.

In this case, two mutations in two different genes caused the same phenotype: dark-colored fur. Try again.

Correct! Dark-colored fur has evolved multiple times in rock pocket mouse populations. Once a mutation that causes dark fur arises in a population, similar selection pressures favor similar dark phenotypes on dark lava flows. Select another correct answer. You selected all the correct answers.