BIOL101 Module 4: Evolution and Natural
Selection
Practice Questions & Answers with
Detailed Explanations
SECTION 1: DARWIN'S THEORY & THE MECHANISM OF
NATURAL SELECTION (Questions 1–15)
Question 1
Which of the following is NOT an observation or inference on
which Darwin's theory of natural selection is based?
A) There is heritable variation among individuals
B) Poorly adapted individuals never produce offspring
C) More offspring are produced than can survive
D) Individuals with favorable traits are more likely to survive and
reproduce
Correct Answer: B) Poorly adapted individuals never
produce offspring
Explanation: This is a common misconception. Poorly adapted
individuals may produce fewer offspring or have lower survival
,rates, but they do not "never" produce offspring. Natural
selection acts on variation in reproductive success, not on
absolute failure. The key observations are: (1) variation exists
among individuals, (2) more offspring are produced than can
survive, and (3) some traits are heritable and confer advantages
in survival and reproduction.
Question 2
Darwin referred to the "survival of the fittest" as:
A) Natural selection
B) Artificial selection
C) Genetic drift
D) Adaptive radiation
Correct Answer: A) Natural selection
Explanation: Darwin used the phrase "survival of the fittest" to
describe natural selection, drawing an analogy to artificial
selection (selective breeding) practiced by humans. In nature,
the environment acts as the selective agent, favoring individuals
with traits that enhance survival and reproduction.
Question 3
Darwin's two main observations that led to his theory of natural
selection were:
,A) Species are fixed and populations remain constant in size
B) Organisms vary and more offspring are produced than can
survive
C) Traits are acquired during an organism's lifetime and passed
to offspring
D) All organisms are perfectly adapted to their environments
Correct Answer: B) Organisms vary and more offspring are
produced than can survive
Explanation: Darwin observed that (1) individuals within a
population vary in their traits, and (2) populations tend to
produce more offspring than the environment can support.
These observations led him to infer that individuals with
favorable variations are more likely to survive and reproduce,
passing those traits to the next generation.
Question 4
Natural selection works by:
A) Selecting the largest organisms to survive
B) Favoring organisms with the most genetic variation
C) Allowing organisms with favorable traits to survive and
reproduce
D) Ensuring that all organisms reproduce equally
Correct Answer: C) Allowing organisms with favorable traits
to survive and reproduce
Explanation: Natural selection is the differential survival and
reproduction of individuals due to differences in phenotype. It
does not simply favor the largest or most variable organisms;
, rather, it favors traits that enhance fitness (survival and
reproductive success) in a given environment. Not all organisms
reproduce equally; some leave more offspring than others.
Question 5
Which of the following statements about natural selection
is TRUE?
A) Natural selection acts on genotypes directly
B) Natural selection results in organisms perfectly adapted to
their environments
C) Natural selection acts on phenotypes
D) Natural selection is a random process
Correct Answer: C) Natural selection acts on phenotypes
Explanation: Natural selection acts on phenotypes (observable
traits) because phenotypes interact with the environment.
However, the selection of phenotypes results in changes in
allele frequencies in the population. Natural selection is NOT
random—it favors traits that enhance fitness—but mutations,
which provide the raw material for selection, are random.
Organisms are not "perfectly" adapted; they are only as
adapted as the existing variation allows.
Question 6
Which of the following best describes the relationship between
natural selection and evolution?
Selection
Practice Questions & Answers with
Detailed Explanations
SECTION 1: DARWIN'S THEORY & THE MECHANISM OF
NATURAL SELECTION (Questions 1–15)
Question 1
Which of the following is NOT an observation or inference on
which Darwin's theory of natural selection is based?
A) There is heritable variation among individuals
B) Poorly adapted individuals never produce offspring
C) More offspring are produced than can survive
D) Individuals with favorable traits are more likely to survive and
reproduce
Correct Answer: B) Poorly adapted individuals never
produce offspring
Explanation: This is a common misconception. Poorly adapted
individuals may produce fewer offspring or have lower survival
,rates, but they do not "never" produce offspring. Natural
selection acts on variation in reproductive success, not on
absolute failure. The key observations are: (1) variation exists
among individuals, (2) more offspring are produced than can
survive, and (3) some traits are heritable and confer advantages
in survival and reproduction.
Question 2
Darwin referred to the "survival of the fittest" as:
A) Natural selection
B) Artificial selection
C) Genetic drift
D) Adaptive radiation
Correct Answer: A) Natural selection
Explanation: Darwin used the phrase "survival of the fittest" to
describe natural selection, drawing an analogy to artificial
selection (selective breeding) practiced by humans. In nature,
the environment acts as the selective agent, favoring individuals
with traits that enhance survival and reproduction.
Question 3
Darwin's two main observations that led to his theory of natural
selection were:
,A) Species are fixed and populations remain constant in size
B) Organisms vary and more offspring are produced than can
survive
C) Traits are acquired during an organism's lifetime and passed
to offspring
D) All organisms are perfectly adapted to their environments
Correct Answer: B) Organisms vary and more offspring are
produced than can survive
Explanation: Darwin observed that (1) individuals within a
population vary in their traits, and (2) populations tend to
produce more offspring than the environment can support.
These observations led him to infer that individuals with
favorable variations are more likely to survive and reproduce,
passing those traits to the next generation.
Question 4
Natural selection works by:
A) Selecting the largest organisms to survive
B) Favoring organisms with the most genetic variation
C) Allowing organisms with favorable traits to survive and
reproduce
D) Ensuring that all organisms reproduce equally
Correct Answer: C) Allowing organisms with favorable traits
to survive and reproduce
Explanation: Natural selection is the differential survival and
reproduction of individuals due to differences in phenotype. It
does not simply favor the largest or most variable organisms;
, rather, it favors traits that enhance fitness (survival and
reproductive success) in a given environment. Not all organisms
reproduce equally; some leave more offspring than others.
Question 5
Which of the following statements about natural selection
is TRUE?
A) Natural selection acts on genotypes directly
B) Natural selection results in organisms perfectly adapted to
their environments
C) Natural selection acts on phenotypes
D) Natural selection is a random process
Correct Answer: C) Natural selection acts on phenotypes
Explanation: Natural selection acts on phenotypes (observable
traits) because phenotypes interact with the environment.
However, the selection of phenotypes results in changes in
allele frequencies in the population. Natural selection is NOT
random—it favors traits that enhance fitness—but mutations,
which provide the raw material for selection, are random.
Organisms are not "perfectly" adapted; they are only as
adapted as the existing variation allows.
Question 6
Which of the following best describes the relationship between
natural selection and evolution?
