IB Biology HL 4.1.13 Hardy-Weinberg equation Question Bank
Practise IB Biology HL 4.1.13 by applying hardy-weinberg equation concepts to exam-style questions.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- identify the relevant biological structure, process or evidence
- apply the correct biological mechanism to the question
- evaluate the result using data, adaptation or ecological reasoning
D4.1.13 (HL)—Hardy-Weinberg equation question 1
[Maximum number: 2]
In fruit flies (Drosophila melanogaster) the allele for long wings is dominant to the allele for short (vestigial) wings. In a laboratory population of 200 flies there were 168 with long wings. Using the Hardy-Weinberg equation, calculate the percentage of flies that would be heterozygous for this characteristic. Show your working.
Complete correct answer:
200 - 168 = 32 flies had short wings.
q^2 = 32 / 200 = 0.16
q = 0.4 p = 0.6
2pq = 2 x 0.6 x 0.4 = 0.48
Percentage of heterozygotes = 48%.
Marking guidance from the official markscheme:
Award 1 mark for correct working showing the Hardy-Weinberg logic, and 1 mark for the correct answer of 48%.
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