Lesson 4.2.2

4.2.2 Natural selection and evolution Quiz: Pearson Edexcel Biology, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.2.2, Natural selection and evolution: 20 multiple choice questions for the Pearson Edexcel Biology (9BI0), Unit 4: Biodiversity and Natural Resources, written with Revision Ninja.

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The 20 questions

  1. Which process causes evolution through differential survival of organisms with advantageous alleles?

    • Genetic drift
    • Natural selection
    • Gene flow
    • Speciation

  2. What must be present in a population for natural selection to occur?

    • Constant environmental conditions
    • High mutation rate
    • Heritable genetic variation
    • Equal reproductive success

  3. Which pattern of selection favours individuals at one extreme of a range of traits?

    • Directional selection
    • Random genetic drift
    • Disruptive selection
    • Stabilising selection

  4. Which pattern of selection favours intermediate phenotypes and reduces variation?

    • Founder effect
    • Disruptive selection
    • Stabilising selection
    • Directional selection

  5. Which pattern of selection favours both extremes and can lead to two distinct forms?

    • Directional selection
    • Stabilising selection
    • Gene flow
    • Disruptive selection

  6. How is evolution defined in terms of genetics over generations?

    • Constant gene pool
    • Increased chromosome number
    • Changing allele frequencies
    • Loss of alleles

  7. What main outcome directly results from the overproduction of offspring in a population?

    • Competition for resources
    • Random genetic drift
    • Decreased genetic diversity
    • Increased mutation rate

  8. Which characteristic must a trait possess to be acted upon by natural selection?

    • It is non-genetic
    • It is heritable
    • It is learned
    • It is acquired

  9. If birds preferentially prey on light beetles, what happens to the dark allele frequency?

    • It increases
    • It decreases
    • It becomes zero
    • It remains unchanged

  10. What acts as the selection pressure driving antibiotic resistance in bacteria?

    • Binary fission
    • Antibiotic exposure
    • High temperature
    • Random gene mutation

  11. What role does genetic variation play in the process of natural selection?

    • Enables differential survival
    • Ensures identical phenotypes
    • Prevents gene mutations
    • Eliminates selection pressure

  12. Over what timeframe do adaptations develop within a population undergoing natural selection?

    • Over many generations
    • During single fertilisation
    • Instantly upon exposure
    • Within one lifetime

  13. Unlike natural selection, what drives allele frequency changes in genetic drift?

    • Environmental adaptation
    • Selective pressures
    • Chance events
    • Differential reproduction

  14. What determines whether a specific allele is advantageous or disadvantageous to an organism?

    • Mutation rate
    • Gene size
    • Dominance of allele
    • Environmental context

  15. What effect does stabilising selection have on phenotypic variation around the mean value?

    • Decreases variation
    • Shifts mean right
    • Shifts mean left
    • Increases variation

  16. If an allele increases survival, what happens to its frequency over several generations?

    • It becomes zero
    • It decreases
    • It increases
    • It remains constant

  17. In evolutionary biology, what does the term 'fitness' primarily refer to?

    • Running speed
    • Reproductive success
    • Physical strength
    • Body size

  18. What term describes environmental factors that influence an organism's chances of survival?

    • Genetic drift
    • Mutational load
    • Selection pressures
    • Founder effect

  19. Which term describes a random change in allele frequency that is most important in small populations?

    • Natural selection
    • Directional mutation
    • Genetic drift
    • Stabilising selection

  20. Over several generations the mean beak length of a bird population increases because longer beaks reach food better. Which pattern of selection is this?

    • Stabilising selection
    • Disruptive selection
    • Sexual selection only
    • Directional selection

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