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A Level H1 Biology Evolution Diversity Quiz
Free Exam-Derived Gemma 4 31B A Level H1 Biology Evolution Diversity quiz with questions and answers for Singapore students. This page is rendered as a direct URL so the questions and answers can be discovered without pressing in-page buttons.
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Questions
A-Level Biology H1 Quiz - Evolution Diversity
Name: ____________________
Class: ____________________
Date: ____________________
Score: ________ / 60
Duration: 75 Minutes
Total Marks: 60
Instructions:
- Answer all questions in the spaces provided.
- Use a black or blue pen.
- For structured questions, ensure your explanations are systematic and use biological terminology.
Section A: Short Answer & Knowledge (Questions 1–8)
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State the primary mechanism by which new alleles are introduced into a population's gene pool. [1]
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Define the term 'speciation'. [2]
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List two pieces of evidence that support the theory of evolution. [2]
(i) ________________________________________________________________________ (ii) ________________________________________________________________________ -
Distinguish between homologous structures and analogous structures. [2]
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Explain why a sudden change in environmental conditions can lead to a shift in the allele frequency of a population. [3]
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Describe the role of mutation in the process of natural selection. [3]
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State the three domains of life used in modern biological classification. [3]
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Explain why the use of rRNA sequences is often preferred over morphological characteristics when determining the phylogenetic relationship between two distantly related species. [3]
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Section B: Structured Response & Data Interpretation (Questions 9–16)
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A population of beetles exists in two colors: green and brown. A drought turns the lush green vegetation brown. (a) Describe how natural selection would act on this population. [4]
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(b) Predict the change in the phenotypic ratio of the population over several generations. [1]
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With reference to the concept of allopatric speciation, explain how a geographic barrier leads to the formation of two distinct species. [4]
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Consider a phylogenetic tree showing the relationship between mammals, birds, and reptiles. (a) What does a 'node' on a phylogenetic tree represent? [1]
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(b) If two species share a more recent common ancestor, how is this represented on the tree? [2]
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Explain the difference between divergent evolution and convergent evolution, providing one example for each. [4]
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A scientist compares the amino acid sequences of cytochrome c in humans, chimpanzees, and yeast. (a) Which two organisms are likely to have the most similar sequences? [1]
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(b) Explain how this molecular evidence supports the theory of evolution. [3]
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Describe the process of sympatric speciation and provide one possible mechanism that could trigger it without geographic isolation. [4]
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In a small island population of birds, a rare allele for a larger beak size appears. Due to a bottleneck effect, this allele becomes fixed in the population. (a) Define 'bottleneck effect'. [2]
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(b) Explain why genetic drift has a more significant impact on small populations than on large ones. [3]
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Explain the relationship between the binomial system of nomenclature and the hierarchical classification of organisms. [3]
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Section C: Extended Response (Questions 17–20)
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Discuss the evidence provided by the fossil record in supporting the theory of evolution, and explain one limitation of the fossil record. [5]
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Explain how the principles of natural selection lead to adaptation in a population over time. [5]
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Compare and contrast the use of morphological data and molecular data in constructing phylogenetic trees. [5]
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Evaluate the statement: "Evolution is a random process." Use your knowledge of mutation and natural selection to justify your answer. [5]
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Answers
Answer Key - A-Level Biology H1 Quiz: Evolution Diversity
1. Mutation. [1]
2. The evolutionary process by which populations evolve to become distinct species [1] such that they are no longer able to interbreed to produce fertile offspring [1]. [2]
3. Any two from: Fossil record, Comparative anatomy (homologous structures), Molecular evidence (DNA/protein sequences), Biogeography. [2]
4. Homologous structures: Similar anatomy due to common ancestry but may have different functions [1]. Analogous structures: Similar function but different anatomy due to convergent evolution/different ancestry [1]. [2]
5. Environmental change alters the selection pressure [1]. Individuals with alleles that provide a survival advantage in the new environment are more likely to survive and reproduce [1], passing these alleles to the next generation, thus increasing the allele frequency [1]. [3]
6. Mutation creates new alleles/genetic variation [1]. This provides the raw material upon which natural selection acts [1]. Beneficial mutations increase the fitness of the individual, leading to higher reproductive success [1]. [3]
7. Archaea, Bacteria, Eukarya. [3]
8. rRNA is present in all cellular organisms [1]. It evolves very slowly (highly conserved) [1], making it possible to trace relationships over very long evolutionary timescales where morphological changes are too great to be reliable [1]. [3]
9. (a) Brown beetles are better camouflaged against the brown vegetation [1]. They are less likely to be preyed upon by predators compared to green beetles [1]. Brown beetles have a higher survival rate and are more likely to reproduce [1], passing the 'brown' allele to offspring [1]. (b) The proportion of brown beetles will increase / The ratio will shift heavily toward the brown phenotype. [1]
10. A population is split by a physical barrier (e.g., mountain range/river) [1]. The two separated populations face different selection pressures/environments [1]. Over time, genetic divergence occurs through mutation and natural selection [1]. Eventually, reproductive isolation is achieved, and they cannot interbreed even if the barrier is removed [1]. [4]
11. (a) The most recent common ancestor of the lineages branching from that point. [1] (b) They will be connected by a node that is closer to the tips of the tree [1] (shorter path distance between them) [1]. [2]
12. Divergent: Related species evolve different traits due to different environments (e.g., Darwin's finches beaks) [2]. Convergent: Unrelated species evolve similar traits due to similar selection pressures (e.g., wings of bats and insects) [2]. [4]
13. (a) Humans and chimpanzees. [1] (b) Cytochrome c is a highly conserved protein [1]. A smaller number of amino acid differences indicates a more recent common ancestor [1], supporting the idea that humans and chimps diverged more recently than they did from yeast [1]. [3]
14. Speciation occurring within the same geographic area [1]. Mechanism: Polyploidy (common in plants) [1] or strong disruptive selection/sexual selection (behavioral isolation) [1]. This creates a reproductive barrier between groups in the same location [1]. [4]
15. (a) A sharp reduction in the size of a population due to environmental events [1], resulting in a loss of genetic diversity [1]. (b) In small populations, chance events have a larger proportional effect on allele frequencies [1]. A single individual's failure to reproduce can eliminate an allele entirely [1], whereas in large populations, the law of large numbers buffers against such random fluctuations [1]. [3]
16. Binomial nomenclature provides a unique two-part name (Genus species) for each organism [1]. This name reflects the organism's position in the hierarchical classification system [1], specifically identifying its genus and species [1]. [3]
17. Evidence: Shows transitional forms (e.g., Archaeopteryx) [1], demonstrates gradual change in morphology over time [1], and provides a timeline of when certain traits appeared [1]. Limitation: Fossil record is incomplete [1] because not all organisms fossilize well (e.g., soft-bodied) or all fossils are not discovered [1]. [5]
18. Variation exists within a population due to mutation/meiosis [1]. Individuals with traits better suited to the environment have a survival advantage (higher fitness) [1]. These individuals are more likely to survive to reproductive age [1] and pass their advantageous alleles to offspring [1]. Over generations, these traits become more common, resulting in adaptation [1]. [5]
19. Morphological: Based on physical traits [1]; easier to observe in fossils [1]; however, can be misleading due to convergent evolution (analogous structures) [1]. Molecular: Based on DNA/protein sequences [1]; provides more precise, quantitative data and is less prone to convergence [1]; however, requires living tissue or very well-preserved ancient DNA [1]. (Any 5 points/comparisons). [5]
20. The statement is partially true/false [1]. Mutation is random; it occurs without regard to the needs of the organism [1]. However, natural selection is NOT random [1]; it systematically preserves beneficial traits and eliminates harmful ones based on environmental fitness [1]. Therefore, the direction of evolution is driven by non-random selection [1]. [5]