Lesson 4.2.2

4.2.2 Natural selection and evolution Quiz: Pearson Edexcel Biology A (Salters-Nuffield), Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

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

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. What is natural selection?

    • The deliberate breeding of organisms by humans for specific traits
    • The process by which individuals with favourable heritable traits survive and reproduce more than others
    • The movement of individuals from one habitat to another
    • The random change of allele frequencies in a very small population

  2. Which of the following is needed for natural selection to occur?

    • Individuals that never reproduce
    • Variation within a population that is heritable and affects survival or reproduction
    • A population in which all individuals are genetically identical
    • A constant environment that never changes

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

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

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

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

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

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

  6. Which statement describes how evolution occurs through natural selection?

    • Individuals evolve new traits during their lifetime and pass them to their offspring
    • Organisms deliberately choose traits that will help future generations
    • Species evolve in a single generation whenever the environment changes
    • Allele frequencies in a population change over generations as advantageous alleles are passed on more often

  7. Why does overproduction of offspring matter for natural selection?

    • It ensures that every offspring survives to adulthood
    • More offspring are produced than can survive
    • It prevents genetic variation from arising
    • It means that no offspring will compete for resources

  8. Which factor makes a trait subject to natural selection?

    • The trait is heritable and affects an individual's chance of survival and reproduction
    • The trait is acquired during life through learning
    • The trait is never affected by the environment
    • The trait is found only in the individual that has it

  9. A population of beetles has a dark form and a light form. In a region where birds hunt the light form more, what is the likely outcome?

    • The frequency of the dark allele increases over generations
    • Both forms become extinct within a single generation
    • The light allele becomes dominant in every generation
    • The population evolves by mutation alone without selection

  10. Which of these is an example of antibiotic resistance evolving through natural selection?

    • Bacteria deliberately change their DNA when they are given antibiotics
    • Bacteria with a resistance allele survive treatment and reproduce, increasing the allele's frequency
    • Antibiotics cause every bacterium to acquire a new gene at once
    • All bacteria become resistant at the same moment after treatment

  11. What is the role of genetic variation in natural selection?

    • It ensures that every individual has the same fitness
    • It provides the raw material on which selection can act
    • It is produced only by natural selection itself
    • It stops selection from acting on the population

  12. Which statement about adaptation through natural selection is correct?

    • Adaptations can be produced by individuals choosing to change their genes
    • Adaptations appear in individuals during their lifetime in response to need
    • Adaptations arise over many generations as advantageous traits become more common in a population
    • Adaptations are always caused by a single mutation in one generation

  13. What is the main difference between natural selection and genetic drift?

    • Selection only occurs in asexual organisms
    • Drift and selection both act only in very large populations
    • Drift is directed towards advantageous alleles, while selection is random
    • Selection changes allele frequencies

  14. Why can a mutation that is harmful in one environment become beneficial in another?

    • Mutations are always harmful in every environment
    • The advantage of a trait depends on the environment
    • Mutations become beneficial only when they occur in gametes
    • The environment changes the DNA sequence to suit the mutation

  15. Which result of selection would you expect for a trait with stabilising selection over many generations?

    • A trait that is completely absent from the population
    • Increasing variation with more extreme forms
    • Less variation in the trait around the mean value
    • Two separate peaks in the distribution of the trait

  16. A species has a population of 100, with 20 per cent carrying an allele that increases survival. After several generations of selection, what would you expect?

    • The population size becomes unrelated to the allele's frequency
    • The proportion carrying the allele increases over time
    • The allele is lost because it cannot be inherited
    • The proportion carrying the allele falls to zero in one generation

  17. What is meant by the term 'survival of the fittest'?

    • Only the largest species in a habitat survive long-term
    • Individuals must be physically fit to be able to breed
    • The strongest individuals always win every fight in a population
    • Individuals best suited to their environment are more likely to survive and reproduce, passing on their alleles

  18. Which of these best describes a selection pressure?

    • A pressure applied by humans to change the population size
    • An environmental factor, such as predation or climate, that affects which individuals survive and reproduce
    • An internal force that causes mutations in the genome
    • A physical pressure inside a cell that controls its shape

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

    • Natural selection
    • Genetic drift
    • Directional mutation
    • 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
    • Sexual selection only
    • Disruptive selection
    • Directional selection

All Pearson Edexcel Biology A (Salters-Nuffield) quizzes