The harlequin ladybird, Harmonia axyridis, is an insect that shows discontinuous variation in colour pattern and continuous variation in body size.

Mark scheme

Marking points from the official mark scheme (May/June 2024). The mark or mark type is shown in brackets.

1. [1] (a) Discontinuous variation: involves distinct/discrete/categoric forms/phenotypes/categories that do not overlap or form a gradual range, with no intermediates, and typically few forms; Continuous variation: involves forms/phenotypes/categories that are not distinct/discrete, overlap, and form a gradual range/spectrum with many different forms/values.
2. [1] (a) Discontinuous variation: does not show a normal distribution/few bars on a bar chart; Continuous variation: shows a normal distribution or bell-shaped curve on a graph.
3. [1] (a) Discontinuous variation: shows no/little effect from the environment; Continuous variation: shows some/large effect from the environment.
4. [1] (b) one / two, genes (control colour pattern);
5. [1] (b) different alleles of a gene have a large effect ;
6. [1] (b) multiple / three, alleles;
7. [1] (b) gene interaction / epistasis;
8. [1] (b) AVP;
9. [1] (c) temperature / food (supply);
10. [1] (c) of larva / during larval development;
11. [1] (c) egg size / diet of mother / size of mother;