CAIE A Level Biology 9700 · Selection and evolution
A small group of birds from a large mainland population colonises a remote island. The mainland population has a wide range of allele frequencies for a gene controlling beak size. Outline how the founder effect may affect the allele frequencies for this gene in the island population.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Outline means: Give the main points briefly. Less detail than describe, but every key step has to be there. One short line per step, in order. The marks are for coverage, not depth.
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