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Question 1
A group of students wanted to investigate the species diversity in a local woodland. |
a) | What is meant by species diversity?
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b) | The students wanted to calculate the index of diversity for the woodland. Give two pieces of data they would need in order to calculate an index of diversity.
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c) | The students took a large number of random samples when investigating the woodland. Explain why it was important for them to take a large number of samples.
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d) | Explain why it was important that their samples were random.
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Question 2
A student investigated the species richness and index of diversity of animal species in the centre of a field and in its surrounding hedges. His results are shown in the table below. |
a) | Calculate the species richness for each habitat.
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b) | Calculate the Simpson's index of diversity for the hedges. Use the following formula: D=1−(Σ(Nn)2) where N = total number of organisms and n = total number of organisms of each species. Give your answer to 1 decimal place.
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c) | The index of diversity was much higher in the hedge than in the centre of the field. Explain why.
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d) | Some farmers are replanting hedges on their farmland. Suggest one advantage and one disadvantage of replanting these hedges.
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Question 3
Bison are large land mammals that were driven out of the United Kingdom by hunting and habitat loss. Recently four bison have arrived in north Kent as part of a rewilding project. Bison increase habitat diversity by knocking down trees, stripping off bark, and making dust baths. |
a) | What is meant by habitat diversity?
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b) | A key benefit of the reintroduction of bison is the predicted increase in habitat diversity. Explain how the knocking down of trees and the stripping of bark increases habitat diversity.
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c) | Suggest one other advantage of reintroducing bison to the United Kingdom.
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d) | Increasing habitat diversity may lead to an increase in both species and genetic diversity. Explain how.
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Question 4
A student investigated how cutting plants in his back garden affected the biodiversity of insects. He created two sample areas, each measuring 3 m x 3 m. He left one sample area untreated and used a lawnmower to cut the plants every fortnight in the other sample area. After 3 months, he collected data on five insect species found in each sample area. The table below shows his results. |
a) | Species richness and an index of diversity can be used to measure biodiversity in an ecosystem. What is the difference between these two measures of biodiversity?
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b) | Calculate the Simpson's index of diversity for the untreated area. Use the following formula. D=1−(Σ(Nn)2) where N = total number of organisms and n = total number of organisms of each species. Give your answer to 2 decimal places.
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c) | Describe and explain the effect of cutting plants on the biodiversity of insects.
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d) | There are ethical and economic arguments for maintaining biodiversity. Give one ethical and one economic argument for maintaining biodiversity.
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Question 5
A group of students investigated the population size of daisies in two different fields. One field included a pathway often used by residents of the town, whereas the other field was undisturbed. |
a) | Describe how the students could estimate the size of the daisy population in each field.
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b) | The students wanted to find out if there was a significant difference between the population size of daisies in the two fields. Name the statistical test they would need to use and explain your choice.
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c) | Give the null hypothesis for this statistical test.
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d) | The students found that the field with the pathway contained fewer daisies. Suggest why.
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Question 6
A group of scientists investigated the biodiversity of butterflies in two different areas over a period of 5 months. They collected butterflies from ten sites in each area every month. Their results are shown in the diagrams below. |
a) | Define species richness.
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b) | One of the scientists used the data above to conclude that the woodland provides a more suitable habitat for the butterflies than the park. Do the data support this conclusion? Explain your answer.
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c) | Give two ways in which the scientists could have improved their method of data collection. For each suggestion, explain why it would lead to improved results.
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d) | One of the scientists wanted to extend the investigation by investigating the link between butterfly numbers and plant distribution in the park. He wanted to find out how the distribution of plants in the park changed with increased distance from the pathway. Describe how the scientist could use a transect to investigate plant distribution.
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Question 7
A scientist counted the number of invertebrate species present in two different rivers, A and B. The figure below shows the scientist’s results. |
a) | Use the graph above to calculate the Simpson's index of diversity for the invertebrates counted in river A. The formula to calculate the Simpson's index of diversity (D ) is D=1−(Σ(Nn)2) where N is the total number of organisms of all species and n is the total number of organisms of each species. Give your answer to 2 significant figures.
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b) | Explain why it is more useful to calculate an index of diversity than to record the species richness.
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c) | Suggest and explain a reason for the difference in numbers of Slate Drake mayfly in each river.
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d) | The scientist also wanted to investigate the diversity of invertebrates in the areas surrounding the rivers. Explain how they could use a pitfall trap to sample invertebrate biodiversity.
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Question 8
A group of scientists investigated the effect of a herbicide on the diversity of insects. They sprayed several fields with the same volume of different concentrations of the same herbicide. After a period of time, they calculated the mean index of diversity for each field. Their results are shown below. |
a) | The scientists placed traps to collect insects at sites chosen at random. Explain why it was important for them to choose the sites randomly.
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b) | The scientists collected insects using a method that was ethical but also allowed them to accurately identify the species of each insect. Suggest one consideration the scientists should have taken into account to make sure their method was ethical.
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c) | Suggest one consideration the scientists should have taken into account to make sure their method allowed accurate identification of each species.
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d) | During their investigation, the scientists sprayed one field with a solution that did not contain any herbicide. Explain why.
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e) | Explain the relationship between herbicide concentration and the index of diversity of insects.
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Question 9
A student found 60 animals in a soil sample collected from a woodland. They identified the following organisms: 23 earthworms 14 ants 6 beetles 12 leatherjackets 5 millipedes |
a) | What can you conclude about the species evenness in this soil sample? Explain your answer.
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b) | Calculate the Simpson’s index of diversity (D ) for this soil sample. Use the formula: D=1−(Σ(Nn)2) Where n = number of organisms of this species and N = total number of organisms. Give your answer to 2 significant figures.
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c) | A group of scientists studied the genetic polymorphism in a group of black garden ants from this woodland. They studied 42 gene loci from their sample and found that 19 of the gene loci were polymorphic. Calculate the proportion of genetic polymorphic gene loci of this ant species.
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d) | The scientists also studied the genetic polymorphism of yellow meadow ants and found that their genetic polymorphism was 0.32. Evaluate the conclusion that black garden ants show greater genetic polymorphism than yellow meadow ants.
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