WCAS - Washington Comprehensive Assessment of Science Heredity and Biological Evolution Questions and Answers

Question 1

The forelimbs of a human, the wing of a bat, and the flipper of a whale all have a very similar bone structure, despite performing different functions.
Which of the following is the BEST explanation for this observation?

Accepted Answer

These organisms share a common ancestor that had a similar forelimb structure.

Answer

These organisms evolved in similar environmental conditions, leading to similar structures.

Answer

This is a coincidence, and the bone structures developed independently in each species.

Answer

The different functions of the limbs caused the bone structures to become similar over time.

Question 2

In a population of rock pocket mice, most individuals have light-colored fur, which provides camouflage on sandy soil. A volcanic eruption covers the area in dark lava rock. Over many generations, the frequency of mice with dark-colored fur increases significantly in the population. This scenario is an example of:

Accepted Answer

Natural selection

Answer

Acquired characteristics

Answer

Genetic drift

Answer

Artificial selection

Question 3

Which of the following statements BEST describes the primary role of genetic mutation in the process of evolution?

Accepted Answer

Mutations are the ultimate source of new genetic variation in a population.

Answer

Mutations always result in traits that are harmful to an organism's survival.

Answer

Mutations occur in response to environmental pressures to help an organism adapt.

Answer

Mutations guarantee that offspring will be better suited to their environment than their parents.

Question 4

Which statement accurately describes the relationship between genes, chromosomes, and DNA?

Accepted Answer

Genes are segments of DNA, which is tightly coiled to form chromosomes.

Answer

Chromosomes are made of genes, which are long strands of DNA.

Answer

DNA is a segment of a gene, which is located on a chromosome.

Answer

A gene is made of many chromosomes, which are composed of DNA.

Question 5

A scientist is studying the evolutionary relationships between four modern species (A, B, C, and D). By comparing a specific protein sequence, she finds the following number of amino acid differences when compared to a common ancestor: Species A has 3 differences, Species B has 15 differences, Species C has 8 differences, and Species D has 14 differences. Based on this molecular evidence, which two species most likely diverged from a common ancestor MOST recently?

Accepted Answer

Species A and C

Answer

Species B and D

Answer

Species A and B

Answer

Species C and D

Question 6

Which of the following is the best definition of a biological adaptation?

Accepted Answer

A heritable trait that increases an organism's fitness in its specific environment.

Answer

A change in an individual organism's behavior in response to a new environment.

Answer

A short-term, non-heritable physiological change an organism makes to survive.

Answer

A process where an entire population learns a new survival skill simultaneously.