What this practice covers
These questions are drawn from past CIE 9700 Biology papers and filtered to selection and evolution. You answer, you find out immediately whether you were right, and you get the reasoning for the correct option and for each distractor. Wrong answers go to a mistakes locker so you can come back to exactly those.
Practice is free. You need an account only so your progress and your mistakes are still there next time.
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What examiners see students get wrong here
These are the errors that cost marks on selection and evolution, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Saying organisms adapt to their environment during their lifetime, or that a characteristic acquired in life is inherited.
- Saying the antibiotic, or the environment, causes the mutation. Mutations are random and pre-existing; the selection pressure only selects among them.
- Saying bacteria "become immune". They become resistant, and it is the population that changes, not an individual cell.
- Confusing stabilising with directional selection, or forgetting that stabilising selection leaves the mean where it is.
- Treating genetic drift as a form of selection. Drift is chance, and it acts most strongly in small populations.
- Confusing the founder effect with a bottleneck. A founder effect starts a new population from a few colonists; a bottleneck crushes an existing one.
- Starting a Hardy-Weinberg calculation from the dominant phenotype. Only q² can be read directly from the data.
- Forgetting to square-root q² before using p + q = 1, so p is calculated from q² instead of from q.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Selection and evolution revision notes.