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IGCSEBiology
Trial Class

Original practice · 5 questions · 15 marks · about 17 minutes

Natural Selection Practice Questions

Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.

These questions test your understanding of natural selection as the mechanism of evolution and how it leads to changes in a population over time.

Before you open the answers

  • Attempt every question without notes.
  • Show working for calculations and write complete biological statements.
  • Use the suggested time as a guide, not a strict limit on the first attempt.

These are original practice questions. They do not reproduce an official Cambridge paper or official mark scheme.

  1. Question 1

    Paper 4 Extended 4 marks Difficulty 4/5

    Describe the process of natural selection using the example of antibiotic resistance in bacteria.

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    1. Variation exists in the bacterial population: some have a mutation giving antibiotic resistance.
    2. When the antibiotic is applied (selection pressure), non-resistant bacteria die.
    3. Resistant bacteria survive and reproduce: passing the resistance allele to offspring.
    4. Over generations, the proportion of resistant bacteria increases: the population has evolved.

  2. Question 2

    Paper 4 Both 3 marks Difficulty 3/5

    State the four key steps of natural selection.

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    1. Variation exists within a population (due to genetic differences).
    2. There is competition for resources / a selection pressure (e.g. Predation, disease).
    3. Individuals with advantageous traits are more likely to survive and reproduce.
    4. These traits are passed on to the next generation: over time, the population changes.

  3. Question 3

    Paper 4 Extended 3 marks Difficulty 4/5

    Explain the term "adaptive advantage" and give one example.

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    1. A characteristic that increases an organism's chance of survival and reproduction in its environment.
    2. Example: white fur in Arctic foxes provides camouflage in snow: they are less visible to prey and predators.
    3. Individuals with this advantage are more likely to survive, reproduce, and pass on the allele.

  4. Question 4

    Paper 2 Core 2 marks Difficulty 2/5

    State what is meant by "survival of the fittest".

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    1. Organisms best adapted to their environment are more likely to survive.
    2. And reproduce, passing on their favourable alleles to the next generation.

  5. Question 5

    Paper 4 Extended 3 marks Difficulty 4/5

    Explain why natural selection does not lead to "perfect" organisms.

    Show model answer and marking guidance
    1. Selection can only act on existing variation: it cannot create new features on demand.
    2. Environments change over time: what is advantageous now may not be later.
    3. Trade-offs exist: an adaptation for one function may be a disadvantage for another.

Mark the set consistently

Award a point only when the idea is clearly present in the written answer. Correct any missed point in a complete sentence, then test the same skill on a different question several days later.

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