Lesson 3.7.3.2

3.7.3.2 Reproductive separation, genetic drift and speciation Quiz: AQA Biology, Unit 7

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.7.3.2, Reproductive separation, genetic drift and speciation: 20 multiple choice questions for the AQA Biology (7402), Unit 7: Genetics, populations, evolution and ecosystems, written with Revision Ninja.

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The 20 questions

  1. What term describes the evolution of new species from existing ones?

    • Speciation
    • Mutation
    • Stabilising selection
    • Adaptive radiation

  2. Which type of speciation involves a physical geographical barrier?

    • Directional selection
    • Sympatric speciation
    • Allopatric speciation
    • Genetic drift

  3. Which type of speciation occurs without a physical geographical barrier?

    • Sympatric speciation
    • Allopatric speciation
    • Directional selection
    • Geographical isolation

  4. What term describes random changes in allele frequencies in small populations?

    • Stabilising selection
    • Genetic drift
    • Natural selection
    • Gene flow

  5. In which population size does genetic drift have the largest effect?

    • Small populations
    • Equilibrium populations
    • Large populations
    • Infinite populations

  6. What name is given to a severe reduction in population size leading to genetic drift?

    • Founder effect
    • Mutation pressure
    • Genetic bottleneck
    • Sympatric barrier

  7. What stops gene flow between two isolated populations of the same species?

    • Reproductive isolation
    • Genetic drift
    • Natural selection
    • Directional mutation

  8. Two populations of a species live on opposite sides of a river that prevents movement. After 10 000 years they can no longer interbreed. Which type of speciation has occurred?

    • Stabilising selection only
    • Allopatric speciation
    • Sympatric speciation
    • Genetic drift only

  9. Which evolutionary force is mainly responsible for random allele shifts on isolated islands?

    • Active transport
    • Gene flow
    • Genetic drift
    • Stabilising selection

  10. Which mechanism prevents fertilisation from occurring between different species?

    • Genetic drift
    • Hybrid sterility
    • Pre-zygotic isolation
    • Post-zygotic isolation

  11. Polyploidy in a shared habitat typically leads to which type of speciation?

    • Directional selection
    • Sympatric speciation
    • Allopatric speciation
    • Geographical isolation

  12. In which population is genetic drift most likely to change an allele frequency substantially in one generation?

    • A population of 10 000 individuals
    • A population of 1000 individuals
    • A population of 10 individuals
    • A population of 100 individuals

  13. Differing allele frequencies between two separated populations indicate what process?

    • Artificial selection
    • Genetic divergence
    • Heterozygote advantage
    • Stabilising selection

  14. A mountain range separating a population into two groups typically causes what?

    • Sympatric speciation
    • Stabilising selection
    • Allopatric speciation
    • Hybrid vigour

  15. Different environmental pressures acting on isolated populations drive what process?

    • Natural selection
    • Gene flow
    • Random mutation
    • Genetic drift

  16. What is the main driver of adaptation in very large populations?

    • Genetic drift
    • Natural selection
    • Bottleneck effect
    • Founder effect

  17. What process causes isolated populations to develop very different allele frequencies over time?

    • Genetic drift
    • Random mating
    • High gene flow
    • Stabilising selection

  18. What must accumulate over many generations for reproductive isolation to form a new species?

    • Phenotypic mutations
    • Geographical barriers
    • Abiotic factors
    • Genetic differences

  19. Which type of reproductive barrier is illustrated by hybrid sterility in mules?

    • Pre-zygotic barrier
    • Geographical barrier
    • Post-zygotic barrier
    • Temporal barrier

  20. What causes geographical isolation to lead to allopatric speciation over time?

    • Instant genetic drift
    • Accumulation of mutations
    • Equal selection pressures
    • Increased gene flow

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