Lesson 5.6.1

5.6.1 Evolution by gene mutation and natural selection Quiz: Pearson Edexcel Biology, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 5.6.1, Evolution by gene mutation and natural selection: 20 multiple choice questions for the Pearson Edexcel Biology (9BI0), Unit 5: On the Wild Side, written with Revision Ninja.

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The 20 questions

  1. What is the primary source of new alleles in a population?

    • Gene mutation
    • Genetic drift
    • Crossing over
    • Natural selection

  2. What characteristic must a trait have for natural selection to act upon it?

    • Heritable variation
    • Environmental origin
    • Acquired fitness
    • Recessive homozygosity

  3. What change defines evolution within a population over generations?

    • Chromosome number
    • Allele frequency
    • Gene expression
    • Mutation rate

  4. Which process can lead to a change in allele frequency through differential survival?

    • Respiration
    • Osmosis
    • Natural selection
    • Photosynthesis

  5. What happens to the frequency of an advantageous allele in a population over generations?

    • It fluctuates randomly
    • It increases
    • It decreases
    • It stays constant

  6. Why are gene mutations described as random events regarding organismal benefit?

    • Always harmful
    • Unrelated to benefit
    • Caused by selection
    • Occur on schedule

  7. Which process generates the genetic variation needed for natural selection to act upon?

    • Speciation
    • Genetic drift
    • Gene mutation
    • Gene flow

  8. What process leads to an increased frequency of antibiotic resistance alleles in bacteria?

    • Gene flow
    • Natural selection
    • Artificial selection
    • Genetic drift

  9. Where are rare recessive alleles hidden from natural selection in a diploid population?

    • In plasmids
    • In gametes
    • In homozygotes
    • In heterozygotes

  10. What effect does reproductive isolation have on gene flow between populations?

    • Stops selection
    • Prevents mutations
    • Reduces gene flow
    • Increases gene flow

  11. What type of speciation requires geographic isolation between populations?

    • Polyploid speciation
    • Sympatric speciation
    • Allopatric speciation
    • Artificial speciation

  12. What type of speciation occurs without geographic isolation between populations?

    • Adaptive radiation
    • Geographical speciation
    • Sympatric speciation
    • Allopatric speciation

  13. Which type of isolation can lead to sympatric speciation within a shared habitat?

    • Spatial isolation
    • Behavioural isolation
    • Topographic isolation
    • Geographic isolation

  14. What long-term outcome occurs when isolated populations accumulate different allele frequencies?

    • Extinction
    • Genetic equilibrium
    • Speciation
    • Gene flow

  15. What process actually produces new alleles in a population?

    • Natural selection
    • Selective breeding
    • Mutation
    • Genetic drift

  16. A snail population separated by a river diverges into two species. Which process occurred?

    • Artificial selection
    • Gene flow
    • Sympatric speciation
    • Allopatric speciation

  17. Why must adaptive phenotypic changes be genetically controlled to drive evolution?

    • Must be environmental
    • Must be inherited
    • Must prevent selection
    • Must cause mutation

  18. What term describes random changes in allele frequencies, most impactful in small populations?

    • Genetic drift
    • Gene flow
    • Speciation
    • Natural selection

  19. What provides the raw material for natural selection when environmental conditions change?

    • Geographic isolation
    • Gene mutation
    • Random drift
    • Genetic variation

  20. Which geographic barrier can physically isolate two populations, leading to allopatric speciation?

    • A wide river
    • Flowering time
    • Courtship behaviour
    • Chromosome number

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