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O Level Biology Evolution Diversity Quiz

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Questions

O-Level Biology Quiz - Evolution Diversity

Name: __________________________
Class: __________________________
Date: __________________________
Score: ______ / 40

Duration: 45 minutes
Total Marks: 40

Instructions:

Answer all questions.
Write your answers in the spaces provided.
The number of marks is given in brackets [ ] at the end of each question or part question.
Use black or dark blue ink. You may use an HB pencil for any diagrams or graphs.

Section A: Multiple Choice Questions (10 Marks)

Answer all questions. Choose the correct option and write the letter in the box provided.

1. Which of the following best describes the process of natural selection?
A. Organisms change their characteristics during their lifetime to suit the environment.
B. Individuals with advantageous traits are more likely to survive and reproduce.
C. All individuals in a population evolve at the same rate.
D. Environmental changes cause mutations to occur in organisms.

Answer: [ ]

2. The diagram below shows the forelimbs of a human, a bat, and a whale.
(Note: Imagine a diagram showing homologous structures with similar bone arrangements but different functions)
These structures provide evidence for evolution because they suggest that:
A. These animals live in similar environments.
B. These animals share a common ancestor.
C. These animals have identical DNA sequences.
D. These animals evolved independently from different ancestors.

Answer: [ ]

3. Antibiotic resistance in bacteria is an example of evolution by natural selection. Which sequence correctly describes this process?

Resistant bacteria survive and reproduce.
A mutation occurs in some bacteria, making them resistant.
Antibiotics are used, killing non-resistant bacteria.
The population of resistant bacteria increases.

A. 2 → 3 → 1 → 4
B. 3 → 2 → 1 → 4
C. 2 → 1 → 3 → 4
D. 1 → 3 → 2 → 4

Answer: [ ]

4. Which of the following is a source of genetic variation in a population?
A. Mitosis
B. Cloning
C. Mutation
D. Asexual reproduction

Answer: [ ]

5. Fossils of Archaeopteryx show features of both reptiles (teeth, long bony tail) and birds (feathers, wings). This supports the theory of evolution by showing:
A. Birds evolved directly from modern reptiles.
B. Reptiles evolved from birds.
C. An intermediate form between two groups exists.
D. Evolution occurs rapidly over a few years.

Answer: [ ]

6. In a population of moths, dark colouration is dominant (D) and light colouration is recessive (d). If the environment becomes polluted and tree trunks turn black, which genotype is most likely to increase in frequency?
A. dd only
B. DD and Dd
C. dd and Dd
D. DD only

Answer: [ ]

7. Which statement about continuous variation is correct?
A. It is controlled by a single gene.
B. It shows distinct categories with no intermediates.
C. It is influenced by both genetic and environmental factors.
D. Examples include blood group and eye colour.

Answer: [ ]

8. Two species of finches live on the same island but eat different types of seeds. One has a large, strong beak, and the other has a small, thin beak. This difference is likely due to:
A. Genetic engineering
B. Adaptive radiation
C. Artificial selection
D. Random mutation without selection

Answer: [ ]

9. Why is sexual reproduction important for evolution?
A. It produces genetically identical offspring.
B. It increases the rate of mutation.
C. It generates genetic variation in the offspring.
D. It ensures all offspring survive.

Answer: [ ]

10. Which of the following is NOT a condition required for natural selection to occur?
A. Overproduction of offspring
B. Genetic variation within the population
C. Limited resources leading to competition
D. Equal survival rates for all individuals

Answer: [ ]

Section B: Structured Questions (30 Marks)

Answer all questions in the spaces provided.

11. The peppered moth (Biston betularia) exists in two forms: light-coloured and dark-coloured. In the 19th century, industrial pollution in Britain killed lichens on tree trunks and covered them in soot, making the trunks dark.

(a) Before industrialisation, tree trunks were covered in light-coloured lichens. Explain why the light-coloured moths were more common than the dark-coloured moths at this time.
[2]

(b) During the industrial revolution, the number of dark-coloured moths increased significantly. Explain this change using the principles of natural selection.
[4]

(c) In recent years, clean air legislation has reduced pollution, and lichens have returned to the tree trunks. Predict and explain what has happened to the frequency of the dark-coloured moth allele in the population.
[2]

12. Variation is essential for evolution.

(a) Distinguish between continuous and discontinuous variation, giving one example of each.
[4]

Type of Variation	Description	Example
Continuous	_________________________	_________________________
Discontinuous	_________________________	_________________________

(b) State two causes of variation in organisms.
[2]

13. The graph below shows the change in body size of a species of horse over millions of years, based on fossil evidence.
(Note: Imagine a graph showing a general trend from small, multi-toed ancestors like Eohippus to large, single-toed modern horses like Equus)

(a) Describe the trend in body size shown in the fossil record.
[1]

(b) Suggest one advantage of larger body size for horses living in open grasslands.
[1]

14. Darwin’s finches on the Galapagos Islands have different beak shapes adapted to their specific diets.

(a) Name the type of evolution that results in one ancestral species evolving into several different species to fill different ecological niches.
[1]

(b) Explain how isolation contributes to the formation of new species (speciation).
[3]

15. Artificial selection is used by humans to breed plants and animals with desirable traits.

(a) Compare artificial selection with natural selection by completing the table.
[4]

Feature	Natural Selection	Artificial Selection
Selective Agent	_________________________	_________________________
Purpose/Goal	_________________________	_________________________
Time Scale	_________________________	_________________________
Outcome for Organism	_________________________	_________________________

(b) Give one disadvantage of artificial selection in crop plants.
[1]

16. The diagram below represents a phylogenetic tree showing the evolutionary relationships between four species: A, B, C, and D. (Note: Imagine a tree where A and B share a recent common node, C branches off earlier, and D is the outgroup)

(a) Which two species are most closely related? Explain your answer.
[2]

(b) What does the node (branching point) between species A and B represent?
[1]

(c) If species D has a simpler body structure than A, B, and C, does this mean species D is the "ancestor" of the others? Explain.
[1]

17. Genetic drift is another mechanism of evolution, distinct from natural selection.

(a) Define genetic drift.
[1]

(b) Explain the "bottleneck effect" and how it reduces genetic diversity.
[2]

18. Homologous and analogous structures provide different types of evidence for evolution.

(a) Define "analogous structures" and give one example.
[2]

(b) Explain why analogous structures do NOT indicate common ancestry.
[1]

19. Molecular biology provides strong evidence for evolution through DNA and protein comparisons.

(a) Explain how comparing DNA sequences can determine how closely related two species are.
[2]

(b) Cytochrome c is a protein found in many organisms. Why is it useful for studying evolutionary relationships?
[1]

(c) If Species X and Species Y have 98% identical DNA sequences for a specific gene, while Species X and Species Z have only 80% identical sequences, which pair is more closely related?
[1]

20. Speciation often requires reproductive isolation.

(a) Define "reproductive isolation."
[1]

(b) Describe one pre-zygotic barrier that prevents mating between two species.
[1]

(d) Why is reproductive isolation necessary for speciation to be complete?
[1]

End of Quiz

Answers

O-Level Biology Quiz - Evolution Diversity: Answer Key

Section A: Multiple Choice Questions

B
Reasoning: Natural selection acts on existing variation; individuals with traits better suited to the environment survive and pass on those traits. A is Lamarckism (incorrect). C is incorrect as evolution varies. D is incorrect; mutations are random, not caused by the environment directly.
B
Reasoning: Homologous structures (similar bone structure, different function) indicate common ancestry.
A
Reasoning: Mutation creates variation (2) → Selection pressure applied (3) → Survival of the fittest (1) → Change in population frequency (4).
C
Reasoning: Mutation is the primary source of new genetic alleles. Mitosis and asexual reproduction produce clones.
C
Reasoning: Archaeopteryx is a "missing link" or transitional fossil showing traits of both groups.
B
Reasoning: Dark colouration is dominant (D). In a dark environment, dark moths (DD and Dd) are camouflaged and survive better.
C
Reasoning: Continuous variation (e.g., height, mass) is usually polygenic and influenced by the environment. A, B, and D describe discontinuous variation.
B
Reasoning: Adaptive radiation occurs when species diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available.
C
Reasoning: Sexual reproduction involves meiosis and fertilization, creating unique genetic combinations (variation).
D
Reasoning: Natural selection requires differential survival. If survival rates are equal, no selection occurs.

Section B: Structured Questions

11. Peppered Moths

(a) Explanation of light moth prevalence:

Light-coloured moths were camouflaged against the light-coloured lichens [1].
Dark-coloured moths were easily seen and eaten by predators (birds) [1].

(b) Natural selection during industrialisation:

Soot darkened the tree trunks, killing lichens [1].
Light-coloured moths became visible to predators and were eaten [1].
Dark-coloured moths were now camouflaged and survived [1].
Surviving dark moths reproduced and passed the dark allele to offspring, increasing its frequency in the population [1].

The frequency of the dark-coloured allele will decrease [1].
As lichens return, light moths are camouflaged again, so dark moths are selected against (eaten) [1].

12. Variation

(a) Continuous vs. Discontinuous:

Continuous: Shows a range of values with no distinct categories; often influenced by environment. Example: Height, weight, skin colour. [2]
Discontinuous: Distinct categories with no intermediates; controlled by genes only. Example: Blood group, eye colour, gender. [2]

(b) Causes of variation:

Mutation (changes in DNA sequence) [1]
Sexual reproduction (meiosis/crossing over/random fertilization) [1]
(Accept: Environmental factors for continuous variation)

If the environment changes, some individuals may possess traits that allow them to survive the new conditions [1].
Without variation, the entire population might be susceptible to the same threat (e.g., disease) and could become extinct [1].

13. Horse Evolution

(a) Trend:

Body size has increased over time [1].

(b) Advantage of larger size:

Longer legs allow for faster running to escape predators in open grasslands [1].
(Accept: Larger digestive system to process tough grass)

Fossilisation is a rare event; many organisms decompose without leaving traces [1].
Soft tissues rarely fossilise, and many fossils may have been destroyed by geological activity or remain undiscovered [1].

14. Darwin’s Finches

(a) Type of evolution:

Adaptive radiation [1].

(b) Role of isolation in speciation:

Geographic isolation (e.g., on different islands) prevents interbreeding between populations [1].
Different environments exert different selection pressures (e.g., different food sources) [1].
Over time, genetic differences accumulate until the populations can no longer interbreed even if brought together (reproductive isolation) [1].

15. Artificial Selection

(a) Comparison Table:

Selective Agent: Natural Selection = Environment/Nature; Artificial Selection = Humans [1]
Purpose/Goal: Natural Selection = Survival/Reproduction; Artificial Selection = Human needs/desires [1]
Time Scale: Natural Selection = Slow (thousands/millions of years); Artificial Selection = Rapid (few generations) [1]
Outcome: Natural Selection = Adaptation to environment; Artificial Selection = Traits beneficial to humans (may reduce survival in wild) [1]

(b) Disadvantage:

Reduced genetic diversity makes crops vulnerable to diseases or pests [1].
(Accept: Undesirable traits may be linked to desirable ones)

16. Phylogenetic Trees

(a) Most closely related:

Species A and B [1].
They share the most recent common ancestor (node) [1].

(b) Node meaning:

It represents a common ancestor from which both species diverged [1].

No [1]. Species D is a modern species that has evolved alongside the others; it is an outgroup, not the direct ancestor.

17. Genetic Drift

(a) Definition:

Random changes in allele frequencies in a population due to chance events [1].

(b) Bottleneck effect:

A sharp reduction in population size due to a catastrophic event [1].
The surviving population has a smaller gene pool, reducing genetic diversity [1].

Chance events have a larger impact on allele frequencies when the sample size (population) is small [1].

18. Homologous and Analogous Structures

(a) Analogous structures:

Structures with similar functions but different evolutionary origins/structures [1].
Example: Wings of a bird and wings of an insect [1].

(b) Why not common ancestry:

They evolved independently due to similar environmental pressures (convergent evolution), not from a shared ancestor with that trait [1].

Analogous [1].
Bird wings are modified forelimbs with bones; insect wings are extensions of the exoskeleton with no bones. They have different structural origins [1].

19. Molecular Evidence

(a) DNA comparison:

Species with more similar DNA sequences share a more recent common ancestor [1].
Fewer differences in base sequences indicate closer relationship [1].

(b) Cytochrome c:

It is a universal protein found in many organisms, allowing for broad comparisons across different species [1].

Species X and Species Y [1] (98% similarity is higher than 80%).

20. Reproductive Isolation

(a) Definition:

Mechanisms that prevent members of different species from producing fertile offspring [1].

(b) Pre-zygotic barrier:

Example: Temporal isolation (breeding at different times), behavioral isolation (different courtship rituals), or habitat isolation [1].

Example: Hybrid sterility (offspring are sterile, e.g., mule) or hybrid inviability (offspring die early) [1].

(d) Necessity for speciation:

It ensures that the gene pools of the two populations remain separate, allowing them to evolve independently into distinct species [1].