Q: A population of flowers has two alleles for color: R (red) and r (white). If the frequency of R is 0.7 and the frequency of r is 0.3, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

$$2pq = 2 \times 0.7 \times 0.3 = 0.42$$

Question 1

Which of the following best explains why genetic diversity within a population increases its ability to survive environmental changes?

Accepted Answer

Genetic diversity increases the likelihood that some individuals possess traits that confer survival advantages under new environmental pressures.

Question 2

A population of beetles is exposed to a new pesticide. After several generations, most beetles are resistant to the pesticide. Which mechanism best explains this change?

Accepted Answer

Natural selection favored beetles with resistance alleles, increasing their frequency in the population.

Question 3

Which of the following is NOT a condition required for Hardy-Weinberg equilibrium?

Accepted Answer

Non-random mating

Question 4

A small population of birds is isolated on an island after a storm. Over time, their allele frequencies differ significantly from the mainland population. This is an example of:

Accepted Answer

Genetic drift (founder effect)

Question 5

Which of the following provides the strongest evidence for the common ancestry of all eukaryotes?

Accepted Answer

Presence of membrane-bound organelles, linear chromosomes, and genes with introns

Question 6

A researcher finds that two populations of frogs can no longer interbreed due to differences in mating calls. This is an example of:

Accepted Answer

Prezygotic isolation

Question 7

Which of the following scenarios best illustrates convergent evolution?

Accepted Answer

Wings in bats and wings in birds, which evolved independently for flight

Question 8

Which equation is used to calculate allele frequencies in a population under Hardy-Weinberg equilibrium?

Accepted Answer

$$p + q = 1$$

Question 9

A population of flowers has two alleles for color: R (red) and r (white). If the frequency of R is 0.7 and the frequency of r is 0.3, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2 	imes 0.7 	imes 0.3 = 0.42$$

Question 10

Which of the following is an example of artificial selection?

Accepted Answer

Humans breeding dogs for specific traits such as size or temperament

Question 11

Which of the following statements about phylogenetic trees is TRUE?

Accepted Answer

They represent hypotheses about evolutionary relationships and can be revised with new evidence.

Question 12

Which of the following best describes punctuated equilibrium?

Accepted Answer

Evolution occurs rapidly after long periods of little or no change.

Question 13

Which of the following is a postzygotic barrier to reproduction?

Accepted Answer

Hybrid sterility

Question 14

Which hypothesis proposes that RNA was the first genetic material capable of self-replication?

Accepted Answer

RNA World Hypothesis

Question 15

Which of the following is a direct result of a population bottleneck?

Accepted Answer

Reduced genetic variation due to a drastic reduction in population size

Question 16

Which of the following types of data is most reliable for constructing phylogenetic trees?

Accepted Answer

Molecular data such as DNA or protein sequences

Question 17

Which of the following best explains why antibiotic resistance in bacteria is considered evidence for ongoing evolution?

Accepted Answer

It provides a real-time example of genetic changes in populations in response to environmental pressures.

Question 18

Which of the following statements about speciation is correct?

Accepted Answer

Sympatric speciation can occur due to polyploidy in plants.

Question 19

Which of the following best describes the relationship between extinction and adaptive radiation?

Accepted Answer

Extinction creates new ecological opportunities, allowing surviving species to diversify and fill available niches.

Question 20

Which of the following is supported by geological evidence regarding the origin of life on Earth?

Accepted Answer

The earliest fossil evidence for life dates to approximately 3.5 billion years ago.

AP Biology Unit 7: Natural Selection and Evolutionary Processes

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