USA 3 Review

Which of the following statements is true about natural selection?

• A) All members of a species adapt in the same way at the same time.

• B) Only the strongest individuals survive without changing.

• C) Natural selection favors traits that help organisms survive and reproduce.

• D) Organisms change their traits whenever the environment changes.

(a)   best demonstrates natural selection.

• A) Bacteria mutating to resist anti
• B) Animals changing their behavior
• C) All organisms in a species becom
• D) A population remaining stable wi

A population of insects is exposed to a pesticide, and over time, some of them develop resistance. What is the best explanation for this?

• A) The insects with resistance were more likely to survive and reproduce.

• B) All insects developed resistance at the same time.

• C) The pesticide became weaker over time.

• D) The resistant insects had been living in a separate area.

Which of the following best describes why limited resources affect reproductive success?

• A) Resources have no effect on survival or reproduction.

• B) Organisms with the best adaptations obtain more resources, leading to higher reproduction rates.

• C) Populations always grow when resources are limited.

• D) All organisms reproduce at the same rate, regardless of resource availability.

Which of the following is an example of gene flow?

• A) A small population of fish develops a new trait after a mutation.

• B) Pollen from one population of sunflowers is carried to another population by animals.

How does gene flow influence the evolution of a population?

• It increases genetic diversity by introducing new genes from other populations.

• It decreases genetic diversity by causing species to lose traits.

• It leads to immediate extinction of the species.

• It results in all organisms having identical traits.

In a population of rabbits, individuals with a dark fur color blend in better with the forest floor, avoiding predators. What type of selection is most likely occurring?

• Stabilizing selection

• Disruptive selection

• Directional selection

• Artificial selection

What happens when a population is exposed to environmental changes, but no variation exists within the population?

• The population will immediately adapt to the changes.

• The population may struggle to survive, as no individuals have traits suited to the new environment.

• New mutations will instantly appear to help the population survive.

• All members of the population will reproduce at the same rate.

A population of lizards is isolated by a river. Over many generations, two distinct groups with different traits emerge. What is this process called?

• Genetic drift

• Gene flow

• Speciation

• Natural selection

Why is the mouse population changing over time?

• The light mice can reproduce more successfully than the dark mice

• The hawks eat more dark mice than light mice because the dark mice taste better

• The hawks eat more light mice than dark mice because they can see the light mice more easily

• The hawks eat more dark mice than light mice because they can see the dark mice more easily