AQA A Level · Biology 7402
5 multiple-choice questions marked as you go, and 4 written questions with worked solutions. All on Investigating diversity.
A researcher is investigating diversity by comparing the base sequences of a specific gene across four different species. The percentage of adenine in the coding strand of this gene for each species is shown below:
Species A: 24%
Species B: 26%
Species C: 24%
Species D: 31%
Which of the following conclusions is most likely correct based only on this data?
A student wants to estimate the species richness of plants in a large meadow using random sampling. Which method would ensure the samples are representative and free from bias?
A scientist investigated the variation in shell height of a snail species in two different habitats. The results were:
Habitat A: Mean = \(12.4 \pm 3.2\) mm
Habitat B: Mean = \(15.8 \pm 2.8\) mm
The values after the \(\pm\) sign represent the standard deviation. What can the scientist conclude from these data?
When investigating diversity, scientists may use immunological comparisons to determine the relationship between species. If the serum of Species X is injected into a rabbit to produce antibodies, and those antibodies are then mixed with the serum of Species Y and Z, which result would indicate that Species Y is more closely related to Species X than Species Z?
A researcher is investigating diversity between two closely related species of insects. Why is comparing the base sequence of DNA generally more informative for determining evolutionary relationships than comparing the amino acid sequence of the same protein?
Distinguish between species richness and the index of diversity when describing the biodiversity of a specific community.
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A student is investigating diversity in a river. They sample 120 individuals across 6 species. The values for \( n(n-1) \) for each species are 2450, 1100, 450, 210, 90, and 2. Calculate the index of diversity (d) for this river to two decimal places.
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When investigating diversity, scientists often calculate the standard deviation of their data. Explain the significance of overlapping standard deviation bars when comparing the mean species richness of two different habitats.
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The following table shows the number of individuals of four different species of insects found in two different fields: a managed wheat field (Field A) and an unmanaged meadow (Field B).
Field A: Species 1 (450), Species 2 (10), Species 3 (5), Species 4 (5).
Field B: Species 1 (120), Species 2 (115), Species 3 (105), Species 4 (130).
a) Calculate the index of diversity \( (d) \) for Field B using the formula: \( d = \frac{N(N-1)}{\sum n(n-1)} \). Show your working. (3 points)
b) Field A has a much lower index of diversity than Field B. Explain how intensive farming techniques contribute to this low diversity. (3 points)
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