The Hardy-Weinberg principleAQA A-Level Biology: Mind map

Exam questions on The Hardy-Weinberg principle

1. A conservation biologist is studying rabbits living on a small island. She records the alleles present in the rabbit population for a gene controlling fur colour and wants to predict the allele frequencies in future generations.
   State two conditions that must apply for the biologist's prediction, based on the Hardy-Weinberg principle, to be valid.2 marks
2. Cystic fibrosis is a human genetic disorder caused by a recessive allele, f. The dominant allele, F, is normal. In one population the incidence of cystic fibrosis is 1 in 2500 births. Assume that the Hardy-Weinberg principle applies to this population.
   Many people with cystic fibrosis die young or do not have children. Explain why the Hardy-Weinberg principle may not predict the frequency of carriers accurately in future generations.2 marks
3. A population of 800 plants of one species has two alleles for flower colour. The allele for red flowers, R, is dominant to the allele for white flowers, r. In the population, 128 of the plants have white flowers. The population is assumed to be in Hardy-Weinberg equilibrium.
   Calculate the frequency of the allele R and the number of heterozygous plants in the population. Show your working.3 marks