Evolution and Biodiversity Practice Questions
IB (International Baccalaureate) · IB Biology HL · 149 free MCQs with instant results and detailed explanations.
149
Total
46
Easy
76
Medium
27
Hard
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Sample Questions from Evolution and Biodiversity
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Q1
Easy
What is the primary mechanism by which evolution occurs according to Darwinian theory?
A.
Natural selection
B.
Genetic drift
C.
Mutation
D.
Gene flow
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Correct Answer: A
Natural selection is the primary mechanism of evolution as proposed by Darwin, where individuals with favorable traits are more likely to survive and reproduce.
Q2
Easy
Which of the following best describes the concept of speciation?
A.
The extinction of a species
B.
The process by which new species arise
C.
The adaptation of a species to its environment
D.
The migration of species across regions
Show Answer & Explanation
Correct Answer: B
Speciation is the evolutionary process by which new biological species arise, typically through processes such as geographic isolation or reproductive isolation.
Q3
Easy
Which of the following is an example of adaptive radiation?
A.
The evolution of mammals after the extinction of dinosaurs
B.
The development of antibiotic resistance in bacteria
C.
The migration of birds during seasonal changes
D.
The variation within a single species in different environments
Show Answer & Explanation
Correct Answer: A
Adaptive radiation is when a single ancestral species rapidly diversifies into a variety of forms to adapt to different environments, exemplified by the evolution of mammals following the extinction of dinosaurs.
Q4
Medium
Which of the following statements correctly describes the process of natural selection?
A.
Natural selection results in the survival of the fittest organisms.
B.
Natural selection ensures that all individuals reproduce equally.
C.
Natural selection acts on genetic variation present in a population.
D.
Natural selection leads to the immediate adaptation of individuals.
Show Answer & Explanation
Correct Answer: C
Natural selection operates on the genetic variation present in a population, favoring individuals with advantageous traits that enhance their survival and reproductive success.
Q5
Medium
In a population of rabbits, fur color is determined by two alleles: B (black) and b (white). If the frequency of allele B is 0.7, what is the expected frequency of homozygous recessive individuals (bb) under Hardy-Weinberg equilibrium?
A.
0.09
B.
0.21
C.
0.49
D.
0.36
Show Answer & Explanation
Correct Answer: A
Using the Hardy-Weinberg equation (q^2), where q is the frequency of the recessive allele (b), we find q = 1 - p = 1 - 0.7 = 0.3. Thus, q^2 = 0.3^2 = 0.09, indicating the frequency of bb individuals.
Q6
Medium
Which of the following best explains the concept of adaptive radiation?
A.
The process by which a single ancestral species diversifies into a wide variety of forms to exploit different niches.
B.
The gradual change of a species through small genetic mutations over time.
C.
The development of new traits in response to environmental pressures.
D.
The reversion of a species to a previous evolutionary form.
Show Answer & Explanation
Correct Answer: A
Adaptive radiation occurs when a single ancestral species evolves into diverse forms that adapt to different environments or niches, leading to a wide variety of species.
Q7
Medium
What evidence supports the theory of evolution by common descent?
A.
Similarities in DNA sequences across different species.
B.
The presence of vestigial structures in modern organisms.
C.
Fossil records showing transitional forms.
D.
All of the above.
Show Answer & Explanation
Correct Answer: D
All options provide strong evidence for evolution by common descent: DNA similarities indicate genetic relationships, vestigial structures demonstrate evolutionary past, and fossils record transitional forms of species.
Q8
Hard
Which of the following statements best describes the concept of speciation through allopatric mechanisms?
A.
Speciation occurs when populations become isolated due to geographic barriers.
B.
Speciation happens when two populations develop different mating behaviors.
C.
Speciation results from the accumulation of genetic changes due to environmental pressures.
D.
Speciation occurs through hybridization of two distinct species.
Show Answer & Explanation
Correct Answer: A
Allopatric speciation is defined by the geographic separation of populations, leading to reproductive isolation and divergence over time.
Q9
Hard
A population of beetles shows a range of shell colors from dark brown to light beige. If a sudden change in the environment causes a shift towards predominantly light-colored sand, which evolutionary mechanism is likely to occur over several generations?
A.
Stabilizing selection favoring medium-colored beetles.
B.
Directional selection favoring lighter-colored beetles.
C.
Disruptive selection favoring both dark and light-colored beetles.
D.
Artificial selection favoring only the dark-colored beetles.
Show Answer & Explanation
Correct Answer: B
Directional selection occurs when environmental changes favor one extreme phenotype, in this case, lighter-colored beetles due to the new light-colored sand environment.
Q10
Hard
Which of the following provides evidence supporting the theory of evolution through natural selection in a population of finches on the Galapagos Islands?
A.
Similarities in beak shapes among different species.
B.
Diversity of color patterns in feathers.
C.
Variations in beak size related to food availability.
D.
Genetic mutations observed in laboratory conditions.
Show Answer & Explanation
Correct Answer: C
Variations in beak size among finches are directly related to their feeding habits, which supports natural selection. Those with beaks better suited to available food sources tend to survive and reproduce more effectively.
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Evolution and Biodiversity — IB (International Baccalaureate) IB Biology HL Practice Questions Online
This page contains 149 practice MCQs for the chapter Evolution and Biodiversity in IB (International Baccalaureate) IB Biology HL. The questions are organized by difficulty — 46 easy, 76 medium, 27 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.