AQA A Level · Biology 7402
5 multiple-choice questions marked as you go, and 4 written questions with worked solutions. All on Populations.
In a population of fruit flies, the length of wings is controlled by a single gene with two alleles. Long wings are dominant to short wings. In a specific population, 36% of the flies have short wings.
Assuming the population is in Hardy-Weinberg equilibrium, calculate the frequency of the dominant allele.
Which of the following conditions is not required for a population to remain in Hardy-Weinberg equilibrium?
In a population of flowers, color is determined by a single gene with two alleles. The frequency of the homozygous recessive genotype (white) is \(0.09\).
Assuming the population is in Hardy-Weinberg equilibrium, calculate the frequency of the heterozygous genotype.
The Bohr effect describes how carbon dioxide concentration affects the oxyhaemoglobin dissociation curve. In a population of high-altitude mammals, the haemoglobin has a higher affinity for oxygen compared to lowland species.
If a mutation occurs that shifts the dissociation curve to the right, which of the following results would be expected at a given partial pressure of oxygen (\(pO_2\))?
In a small island population of finches, a rare allele increases in frequency from \(0.02\) to \(0.15\) over three generations purely by chance, despite providing no selective advantage. This phenomenon is best described as:
In a population of 800 beetles, the frequency of the recessive allele for wing shape is \(0.4\).
Assuming the population is in Hardy-Weinberg equilibrium, calculate the expected number of heterozygous individuals in the population.
Write your answer out first, then check it against the worked solution.
In a stable population of 1500 beetles, the frequency of the recessive phenotype (long antennae) is observed to be 0.09.
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}Assuming the population is in Hardy-Weinberg equilibrium, calculate the number of individuals in this population that are expected to be homozygous dominant.
Write your answer out first, then check it against the worked solution.
A specific population of field mice has two alleles for fur color: B (black) and b (brown). In a stable environment, 16% of the population displays the brown phenotype. Assuming the population is in Hardy–Weinberg equilibrium:
a) Calculate the frequency of the recessive allele (b).
b) Calculate the frequency of the homozygous dominant genotype (BB).
c) Determine the percentage of the population that is heterozygous (Bb).
d) List two conditions that must be met for this population to remain in Hardy–Weinberg equilibrium.
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Succession is a dynamic process that occurs in ecosystems over time.
a) Distinguish between primary succession and secondary succession.
b) Explain how pioneer species change the abiotic environment to allow other species to colonise the area.
c) Why does a climax community typically show higher stability but potentially lower species richness than a mid-successional stage?
Write your answer out first, then check it against the worked solution.
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