Natural Selection

Certain traits become more or less common in a population as a result of differential reproductive success. Which of the following examples describes the condition most likely to change the frequency of a trait within a population?

• A. A large coal mine has been closed and abandoned, thus providing a brown bat population with a new hibernation site.

• B.The food availability for a population of brown bats is severely diminished when a drought reduces the number of mosquitoes.

• C.Injured brown bats are taken to a rehabilitation center where the animals can recover before they are released into the wild.

• D. After a gestation period of 50 days, female brown bats give birth to healthy pups that remain with their mothers for three weeks.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

NGSS.MS-LS4-4

During his trip to the Galapagos Islands, Charles Darwin observed that finches on different islands had different features. Ultimately, how did this observation contribute to Darwin’s theory of natural selection?

• A.He concluded that every instance of species variation results in a beneficial mutation.

• B.He concluded that mutation inhibits the chance that an organism will adapt to its environment.

• C. He concluded that species develop mutations exclusively because of electromagnetic radiation.

• D. He concluded that traits well suited to an organism’s environment are more likely to be passed on to successive generations.

Tags

NGSS.MS-LS4-2

NGSS.MS-LS4-4

3. Scientists have discovered bacteria that can survive in the hot temperatures found in the lava of volcanoes. Which statement best explains how bacteria could survive in this environment?

• A.Bacteria are small enough not to be killed by heat.

• B.Bacteria are simple organisms and can live in any conditions.

• C.Bacteria have mutated and those suited to the environment survive there.

• D. Bacteria grow faster in hot conditions and so are suited to the environment.

Tags

NGSS.MS-LS3-1

NGSS.MS-LS4-4

4. Stabilizing selection is a form of natural selection in which intermediate phenotypes are favored (as shown by the graph of human birth weight and infant mortality below). Which choice best explains the result of stabilizing selection?

• A.Greater variation is produced in the population.

• B.Allele frequencies that give rise to extreme forms of the trait are increased.

• C. A.Individuals in the midrange are shown to be the most unfit in the population.

• D. A.Extremes at both ends of the variation range are eliminated from the population.

Tags

NGSS.MS-LS4-4

5. Which of the following statements best describes what will most likely occur to the moth populations in the image below?

• A. The light moths will be captured by predators more easily than the dark moths, and the population of dark moths will rise.

• B. The light moths will be captured by predators more easily than the dark moths, and the population of light moths will rise.

• C. The dark moths will be captured by predators more easily than the light moths, and the dark moths will probably go extinct.

• D. The light moths will change their wing color to match that of the dark moths.

Tags

NGSS.MS-LS2-4

NGSS.MS-LS4-4

6. What is the most likely explanation of the data shown below?

• A. There has been a drought in the area that is affecting all life forms.

• B. The population of natural predators of the moths has gotten smaller.

• C. The moths are living in an environment with light trees.

• D. The moths are living in an environment with dark trees.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

7. The pair of population graphs below display the results of two different five-year hunting cycles, one on light trees and one on dark trees. The population of light-colored moths is shown by the light gray dots, and the population of dark moths is shown by the dark gray dots. How do these results demonstrate natural selection?

• A. The moth populations shown here demonstrate random fluctuations over time that are not explained by tree color.

• B. On light trees, individual moths tried to become lighter in color to match the tree background. On dark trees, individual moths tried to become darker in color.

• C. The moths that were the same color as their background were more likely to survive and reproduce. Over time, the populations of these well-adapted moths increased.

• D. Small particles of tree bark became embedded in the moth’s wings, causing the moths to become darker on the dark trees and lighter on the light trees. These acquired traits were then passed down to the next generation of moths, causing the populations to change color over time.

Tags

NGSS.MS-LS4-4

8. Suppose a certain species of insect lives in the lush green canopy of the rain forest. Some of the insects are bright green in color, and some are bright yellow. Assume there is a natural predator of the insect in the area. What do you expect to happen to the populations of the green and the yellow insects over time?

• A. The green insect population will increase and the yellow insect population will decrease.

• B. The green insect population will decrease and the yellow insect population will increase.

• C. Both insect populations will remain constant over time.

• D. Both insect populations will increase over time.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

NGSS.MS-LS4-4

9. Natural selection can operate on predator populations as well as on prey. Suppose that over time trees became covered in lichen and the proportion of light moths increased to nearly 100%. What is the most likely consequence for predator populations?

• A. Bird populations will decrease, at least for a while.

• B. Over time, birds with better eyesight will become more common.

• C. Birds may change hunting strategies or seek other sources of food.

• D. All of the above.

Tags

NGSS.MS-LS2-4

10. A large population of cockroaches was sprayed with an insecticide. A few of the cockroaches survived and produced a population of cockroaches that was resistant to this spray. What can best be inferred from this example?

• A. A species will adapt not matter what the environment.

• B.The environment has no effect on the survival of an organism.

• C. Insecticides cause mutations that are passed on to the next generation.

• D.Individuals with favorable variations survive and reproduce.

Tags

NGSS.MS-LS2-4

NGSS.MS-LS4-4