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Secondary 4 Combined Science Biology Evolution Diversity Quiz

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Questions

Secondary 4 Combined Science Biology Quiz - Evolution Diversity

Name: __________________________
Class: __________________________
Date: __________________________
Score: ________ / 30

Duration: 45 minutes
Total Marks: 30

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.
You may use a calculator.

Section A: Multiple Choice Questions (Questions 1–5)

Choose the correct answer and write the letter in the box provided.

1. Which of the following statements best describes the process of natural selection?
A. Organisms change their characteristics during their lifetime to suit the environment.
B. Individuals with advantageous variations are more likely to survive and reproduce.
C. All individuals in a population have an equal chance of survival.
D. Environmental changes cause mutations to occur in organisms.

Answer: [ ] [1]

2. The diagram below shows the forelimbs of a human, a bat, and a whale.

Image pending generation for this question.

(Diagram description: Three skeletal structures showing similar bone arrangements—humerus, radius, ulna, carpals, phalanges—but different shapes and sizes adapted for grasping, flying, and swimming respectively.)

What evidence for evolution do these structures provide?
A. They show that these animals share a common ancestor.
B. They show that these animals live in similar environments.
C. They show that these animals have identical DNA sequences.
D. They show that these animals evolved at the same time.

Answer: [ ] [1]

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 → 2 → 3 → 4

Answer: [ ] [1]

4. Scientists find fossils of an ancient horse species in rock layers. The fossils in the deepest layers have four toes, while fossils in higher layers have one toe. What does this suggest?
A. The horse species became extinct.
B. The horse species evolved gradually over time.
C. The environment remained constant.
D. The horses migrated from a different continent.

Answer: [ ] [1]

5. Which factor is not a source of genetic variation in a population?
A. Mutation
B. Sexual reproduction (meiosis and fertilization)
C. Asexual reproduction
D. Gene flow (migration)

Answer: [ ] [1]

Section B: Structured Questions (Questions 6–10)

6. Define the term species.

[2]

7. The graph below shows the change in the average beak depth of a population of finches on an island over a period of five years. During year 3, a severe drought occurred, resulting in only large, hard seeds being available.

Image pending generation for this question.

(Graph description: X-axis is Year 1-5. Y-axis is Average Beak Depth (mm). The line stays steady at 8mm for Years 1-2, rises sharply to 10mm in Year 3, and stays at 10mm for Years 4-5.)

(a) State the trend in average beak depth during the drought (Year 3).

[1]

(b) Explain, using the concept of natural selection, why the average beak depth changed during the drought.

[3]

8. Industrial melanism is a phenomenon observed in the Peppered Moth (Biston betularia). Before the Industrial Revolution, most moths were light-colored. During the Industrial Revolution, soot darkened the tree trunks, and the population of dark-colored moths increased.

(a) Name the process responsible for this change in moth coloration.

[1]

(b) Explain why the population of dark-colored moths increased in polluted areas.

[3]

9. Two populations of the same species of fish are separated by a land bridge that forms due to a drop in sea level. After thousands of years, the sea level rises again, reconnecting the two populations. However, the two groups can no longer interbreed.

(a) Name the type of speciation that has occurred.

[1]

(b) Suggest two factors that could have led to the two groups becoming different species.

[2]

10. The table below shows the number of individuals with different blood groups in two isolated human populations.

Blood Group	Population A (n=1000)	Population B (n=1000)
A	400	100
B	100	400
AB	50	50
O	450	450

(a) Calculate the percentage of individuals with Blood Group A in Population A.

[1]

(b) Suggest why the frequency of Blood Group A is different in the two populations.

[2]

Section C: Structured Questions (Questions 11–15)

11. Darwin’s finches are a classic example of adaptive radiation.

(a) Define adaptive radiation.

[2]

(b) State one condition necessary for adaptive radiation to occur.

[1]

12. The diagram below shows a phylogenetic tree of four species: A, B, C, and D.

Image pending generation for this question.

(Diagram description: A and B branch from a recent common node. C branches from an older node shared with the A/B lineage. D branches from the oldest node, separate from A, B, and C.)

(a) Which two species are most closely related?

[1]

(b) Explain your answer to (a).

[1]

13. Genetic drift is a mechanism of evolution.

(a) Define genetic drift.

[2]

(b) In which type of population is genetic drift more significant: large or small? Explain why.

[2]

14. Compare artificial selection and natural selection.

Feature	Natural Selection	Artificial Selection
Selecting Agent	____________________	____________________
Purpose/Goal	____________________	____________________

[4]

15. Fossils provide evidence for evolution.

(a) State one limitation of using fossils as evidence for evolution.

[1]

(b) Apart from fossils, name two other sources of evidence for evolution.

[2]

Section D: Free Response Questions (Questions 16–20)

16. The Galapagos Islands are located 1000 km from the mainland of South America. The islands have unique species, such as the Galapagos Tortoise and Marine Iguana, which are found nowhere else in the world.

Explain how the unique species on the Galapagos Islands may have evolved from mainland ancestors. In your answer, include the roles of:

Geographic isolation
Variation
Natural selection

[6]

17. Marine Iguanas feed on algae underwater. They have specialized glands to excrete excess salt. Explain how this adaptation supports the theory of evolution.

[2]

18. Human activities, such as introducing rats and goats to the Galapagos, threaten these unique species. Explain how introduced species can cause the extinction of native species.

[2]

19. Conservation efforts often involve breeding programs in zoos. Discuss one advantage and one disadvantage of captive breeding programs for conserving endangered species.

Advantage: ______________________________________________________________
Disadvantage: ____________________________________________________________
[2]

20. Some scientists argue that evolution is "just a theory." Explain the scientific meaning of the word "theory" in this context and why evolution is considered a robust scientific theory.

[2]

[Total: 30 Marks]

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Answers

Secondary 4 Combined Science Biology Quiz - Evolution Diversity (Answer Key)

Section A: Multiple Choice Questions

1. B
Reasoning: Natural selection acts on existing variation; individuals with traits better suited to the environment survive and reproduce more successfully. A is Lamarckism (incorrect). C is incorrect as survival is not equal. D is incorrect as mutations are random, not caused by the environment.

2. A
Reasoning: Homologous structures (similar bone structure, different function) indicate common ancestry.

3. A
Reasoning: Mutation creates variation (2) → Selection pressure (antibiotics) kills non-resistant (3) → Resistant survive/reproduce (1) → Allele frequency increases (4).

4. B
Reasoning: The gradual change in fossil structure over time indicates evolution.

5. C
Reasoning: Asexual reproduction produces clones (identical offspring), so it does not generate new genetic combinations (variation) unless mutation occurs. Mutation, sexual reproduction, and gene flow all increase variation.

Section B: Structured Questions

A group of organisms that can interbreed [1]
To produce fertile offspring [1]

7.
(a) The average beak depth increased. [1]
(b)

During the drought, only large, hard seeds were available. [1]
Finches with larger/deeper beaks were better able to crack these seeds and survive. [1]
These survivors reproduced, passing the allele for larger beaks to the next generation, increasing the average beak depth. [1]

8.
(a) Natural selection [1]
(b)

Dark-colored moths were better camouflaged against the soot-darkened tree trunks. [1]
They were less likely to be eaten by predators (birds). [1]
Therefore, they survived and reproduced more than light-colored moths, passing on the dark color allele. [1]

9.
(a) Allopatric speciation [1]
(b) Any two of:

Different environmental conditions/selective pressures in the two areas. [1]
Genetic drift / Mutation accumulating differently in isolated groups. [1]
Reproductive isolation mechanisms developing (e.g., behavioral, temporal). [1]

10.
(a) (400 / 1000) × 100 = 40% [1]
(b)

The populations are isolated, preventing gene flow. [1]
Different selective pressures or genetic drift caused the allele frequencies for blood group A to change differently in each population. [1]

Section C: Structured Questions

11.
(a) The rapid evolution of many diverse species from a single ancestral species, usually when a change in the environment makes new resources available or creates new challenges. [2]
(b) Geographic isolation / Availability of diverse ecological niches. [1]

12.
(a) Species A and B [1]
(b) They share the most recent common ancestor (branch point). [1]

13.
(a) A change in the allele frequency of a population due to random chance events. [2]
(b) Small population. [1]

In small populations, random events (e.g., death of a few individuals) have a larger impact on the overall allele frequency. [1]

14.

Selecting Agent: Natural Selection: Environment / Nature [1]; Artificial Selection: Humans [1]
Purpose/Goal: Natural Selection: Survival and reproduction / Adaptation to environment [1]; Artificial Selection: Human needs / Desired traits [1]

15.
(a) Any one:

Fossil record is incomplete (many organisms do not fossilize). [1]
Soft-bodied organisms rarely fossilize. [1]
It is difficult to determine exact relationships/color/behavior from fossils. [1]
(b) Any two:
Comparative anatomy (homologous structures). [1]
Molecular biology (DNA/protein sequence comparison). [1]
Embryology. [1]
Biogeography. [1]

Section D: Free Response Questions

16. Explanation of Evolution on Galapagos (6 marks):

Geographic Isolation: Ancestral species from the mainland arrived on the islands and became geographically isolated from the mainland population. [1]
Variation: There was genetic variation within the arriving population due to mutation and sexual reproduction. [1]
Different Environments: The different islands had different environmental conditions (food sources, climate, predators). [1]
Natural Selection: Individuals with variations best suited to the specific island environment were more likely to survive and reproduce. [1]
Inheritance: These advantageous traits were passed on to offspring. [1]
Speciation: Over many generations, the populations on different islands became so different that they could no longer interbreed, forming new species. [1]

17. Marine Iguana Adaptation (2 marks):

The salt-excreting glands are an adaptation to a marine environment (high salt intake from algae/seawater). [1]
This shows that the species evolved from terrestrial ancestors to exploit a new niche (marine feeding), supporting the idea that evolution leads to adaptation to specific environments. [1]

18. Introduced Species and Extinction (2 marks):

Introduced species (rats/goats) may compete with native species for limited resources (food/shelter). [1]
They may prey on native species (e.g., rats eating eggs) or introduce diseases to which native species have no immunity. [1]

19. Captive Breeding (2 marks):

Advantage: Protects species from immediate threats in the wild (poaching, habitat loss); allows for controlled breeding to increase population size. [1]
Disadvantage: Loss of genetic diversity (inbreeding); animals may lose natural survival skills (hunting/avoiding predators) making reintroduction difficult. [1]

20. Scientific Theory (2 marks):

In science, a "theory" is a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation. [1]
Evolution is considered robust because it is supported by a vast amount of evidence from multiple fields (fossils, genetics, anatomy, etc.). [1]

[Total: 30 Marks]