Biodiversity: OCR A‑Level Biology A questions

Every OCR A-Level Biology A exam question on 4.2.1 Biodiversity, 2016–2025, with its mark scheme and examiner’s report.

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Q17(d)(i)
June 2025 · Paper 2
2 marks4.2.1 Biodiversity
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Q18(a)(i)
June 2025 · Paper 2
1 mark4.2.1 Biodiversity
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Q18(a)(ii)
June 2025 · Paper 2
2 marks4.2.1 Biodiversity
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Q18(b)(i)
June 2025 · Paper 2
1 mark4.2.1 Biodiversity
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Q18(b)(ii)
June 2025 · Paper 2
1 mark4.2.1 Biodiversity
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Q18(c)(i)
June 2025 · Paper 2
3 marks4.2.1 Biodiversity
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Q18(c)(ii)
June 2025 · Paper 2
2 marks4.2.1 Biodiversity
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Q18(c)(iii)
June 2025 · Paper 2
2 marks4.2.1 Biodiversity
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Q18(c)(iv)
June 2025 · Paper 2
4 marks4.2.1 Biodiversity
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Q18(c)(v)
June 2025 · Paper 2
2 marks4.2.1 Biodiversity
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Q18(c)(vi)
June 2025 · Paper 2
1 mark4.2.1 Biodiversity
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Q19(a)(i)
June 2025 · Paper 2
3 marks4.2.1 Biodiversity
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Q19(a)(iv)
June 2025 · Paper 2
1 mark4.2.1 Biodiversity
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Q19(b)(i)
June 2025 · Paper 2
1 mark4.2.1 Biodiversity
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Q18
June 2025 · AS Paper 1
1 mark4.2.1 Biodiversity
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Q19
June 2025 · AS Paper 1
1 mark4.2.1 Biodiversity
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Q25(b)
June 2025 · AS Paper 1
1 mark4.2.1 Biodiversity
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Q18(c)(i)
June 2024 · Paper 2
2 marks4.2.1 Biodiversity
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Q18(c)(ii)
June 2024 · Paper 2
1 mark4.2.1 Biodiversity
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Q2(a)
June 2024 · Paper 3
4 marks4.2.1 Biodiversity
The whole paper ↗

All 111 questions on Biodiversity, as a list

June 2025, Paper 2, Q17(d)(i) (2 marks): Outline how genetic diversity in a species such as Przewalski’s horse can be measured. [2]
June 2025, Paper 2, Q18(a)(i) (1 mark): State why sampling is necessary when measuring the abundance of organisms in a habitat. [1]
June 2025, Paper 2, Q18(a)(ii) (2 marks): Explain why it is important that sampling is random. [2]
June 2025, Paper 2, Q18(b)(i) (1 mark): State the species richness in quadrat A. [1]
June 2025, Paper 2, Q18(b)(ii) (1 mark): Compare the species evenness in quadrats A and B. [1]
June 2025, Paper 2, Q18(c)(i) (3 marks): Calculate the Simpson’s Index of Diversity for the wildflower meadow. f n p 2 n d - R Use the formula: D 1 = N You may use the table above for working out. Give
June 2025, Paper 2, Q18(c)(ii) (2 marks): Explain the significance of the value for D calculated in part (i). [2]
June 2025, Paper 2, Q18(c)(iii) (2 marks): Describe how the students should select their sampling areas for steps 1 and 6. [2]
June 2025, Paper 2, Q18(c)(iv) (4 marks): Suggest two improvements that the students could make to step 2 of their method. For each improvement explain how that would increase the validity of the result
June 2025, Paper 2, Q18(c)(v) (2 marks): Suggest and explain one limitation with step 7 of the students’ method. [2]
June 2025, Paper 2, Q18(c)(vi) (1 mark): Identify one problem with the way in which the students categorised their flying insect species that could reduce confidence in the calculated value for Simpson
June 2025, Paper 2, Q19(a)(i) (3 marks): Identify evidence from the information above that supports each of the following claims: Puffins are important for aesthetic reasons Puffins are important for e
June 2025, Paper 2, Q19(a)(iv) (1 mark): There are two types of conservation: in situ and ex situ. State the type of conservation taking place on the Farne Islands and give a reason for your choice. Ty
June 2025, Paper 2, Q19(b)(i) (1 mark): It is important not to disturb the burrows and there is not enough money avai
June 2025, AS Paper 1, Q18 (1 mark): Scientists studied the genetic diversity of four different wolf populations in a national park in Canada. The data are shown in the table. Population Number of
June 2025, AS Paper 1, Q19 (1 mark): What is the definition of species biodiversity? A The distribution of different species in a habitat B The number of different species in a population C The spe
June 2025, AS Paper 1, Q25(b) (1 mark): Name an international agreement that might use data about the changing numbers of the Asian elephant to monitor its conservation status. [1]
June 2024, Paper 2, Q18(c)(i) (2 marks): Describe the evidence in the table that supports the conclusion that low genetic diversity contributed to the extinction of the thylacine. [2]
June 2024, Paper 2, Q18(c)(ii) (1 mark): Identify one piece of evidence that does not support the conclusion that low genetic diversity contributed to the extinction of the thylacine. [1]
June 2024, Paper 3, Q2(a) (4 marks): A student plans to sample the plant species in the area shown below to assess the area’s species biodiversity. Grassland River Grassland with shrubs and bushes
June 2024, Paper 3, Q2(b)(i) (2 marks): Outline the differences between the bird and mammal results shown in the graph. [2]
June 2024, Paper 3, Q2(b)(ii) (4 marks): A student looking at the graph concluded that ‘climate change is not a major threat to species biodiversity’. Evaluate this conclusion. [4]
June 2024, AS Paper 1, Q17 (1 mark): Which statement describes species evenness? A The number of different species B The number of organisms in a community C The number of organisms of a particular
June 2024, AS Paper 1, Q18 (1 mark): Students carried out fieldwork in two different woodlands. They marked out an area measuring 10 m by 10 m in each woodland. For each plant species present they
June 2024, AS Paper 1, Q19 (1 mark): In situ and ex situ conservation methods maintain biodiversity. Which example describes an ex situ conservation method? A Collecting and storing seeds of clover
June 2024, AS Paper 1, Q26(a) (3 marks): Explain how agriculture can have a negative effect on biodiversity. [3]
June 2024, AS Paper 1, Q26(b) (1 mark): State one factor other than agriculture that can have a negative effect on biodiversity. [1]
June 2024, AS Paper 2, Q1(a)(i) (1 mark): Name the type of sampling method used in a transect line. [1]
June 2024, AS Paper 2, Q1(a)(ii) (3 marks): This table shows their findings. Number of (n / N)2 Species organisms n / N (n) Foxglove 3 0.13 0.02 Meadow buttercup 7 Oxeye daisy 9 Yellow rattle 4 ∑(n / N)2
June 2024, AS Paper 2, Q1(a)(iii) (1 mark): State what can be concluded about the diversity of the field from your answer in (a)(ii). [1]
June 2024, AS Paper 2, Q1(b) (1 mark): The students then used a sweep net to sample animals in two different parts of a river. They did this by holding the sweep net in the water and at the same time
June 2024, AS Paper 2, Q1(c) (1 mark): Black oak trees are an example of a keystone species within an oak woodland ecosystem in England. Suggest what would happen to the ecosystem if the black oak tr
June 2023, Paper 3, Q4(a) (6 marks): The Convention on International Trade in Endangered Species (CITES) came into effect in 1975. (a)* Fig. 4.1 shows the percentage of species threatened with exti
June 2023, Paper 3, Q4(b)(iv) (2 marks): New Zealand has a high species biodiversity compared to many countries. Species biodiversity includes the concepts of species richness and species evenness. Exp
June 2023, AS Paper 1, Q3 (1 mark): Simpson’s Index of Diversity (D) can be used to estimate the biodiversity of a habitat. D = 1 – (∑( N) 2) n Scientists calculated D for a grassland habitat. One
June 2023, AS Paper 1, Q4 (1 mark): What is an example of in situ conservation? A A botanical garden B A breeding programme in a zoo C A marine conservation zone D A seed bank Your answer [1]
June 2023, AS Paper 2, Q4(a) (2 marks): The Humboldt penguin is protected by the Convention on International Trade in Endangered Species (CITES). • The Humboldt penguin lives on the Pacific coast of S
June 2023, AS Paper 2, Q4(b) (3 marks): A study was carried out to monitor the population of three penguin species on an island near Antarctica. The graph shows the results of this study. 1600 Key: Ad
June 2022, Paper 2, Q7 (1 mark): On a biology field trip, a student calculated that an area of ancient woodland had a Simpson’s Index of Diversity of 0.85. Which interpretation of a Simpson’s I
June 2022, Paper 2, Q18(a)(i) (2 marks): Calculate the rate of change in wildebeest population between 1975 and 2007. Rate = animals per year [2]
June 2022, Paper 2, Q18(a)(ii) (6 marks): The Maasai Mara is a grassland ecosystem in east Africa with a large range of wildlife. The human population in the area is increasing. An increasing human popu
June 2022, Paper 2, Q18(b) (3 marks): Maintaining biodiversity in the Maasai Mara is important. The following are some statements about biodiversity in the Maasai Mara: A People visit the Maasai Mar
June 2022, Paper 2, Q20(b)(i) (3 marks): Calculate the Simpson’s Index of Diversity (D) for the students’ data. n 2 f d n p Use the formula: D = 1 – / N D = [3]
June 2022, Paper 2, Q20(b)(ii) (2 marks): The students found grass species difficult to distinguish from one another so they decided to record any grass species as ‘grass’. Explain how the students’ dec
June 2022, Paper 3, Q5(b) (2 marks): DNA analysis can be used to assess genetic biodiversity within populations. A scientist assessed genetic biodiversity in four populations, A to D, of yellow hor
June 2022, AS Paper 1, Q3 (1 mark): The table shows the numbers of different species of invertebrates found in four different areas in a woodland. Invertebrate species Area Woodlice Spiders Beetle
June 2022, AS Paper 1, Q8 (1 mark): International trade in parts of the rhinoceros including rhino horn has been illegal since 1977. Which organisation regulates this trade? A CBD B CITES C CSS D
June 2022, AS Paper 1, Q22(a) (2 marks): Name and define two other levels of biodiversity. Name Definition Name Definition [2]
June 2022, AS Paper 1, Q22(b)(i) (2 marks): Calculate the proportion of polymorphic gene loci in the European zoo population. Proportion = [2]
June 2022, AS Paper 1, Q22(b)(ii) (2 marks): A second group of scientists carried out a separate investigation to calculate the proportion of polymorphic gene loci of cheetahs in European zoos and found th
June 2022, AS Paper 1, Q22(b)(iii) (3 marks): Suggest and explain reasons why, in the 21st Century, only 10% of the gene loci are polymorphic in wild populations of cheetah. [3]
November 2021, Paper 2, Q13 (1 mark): Moving North from a large solitary tree in the school field, some students studied changes in plant species. They laid a tape measure due North from the base of
November 2021, Paper 2, Q14 (1 mark): Which of the following best defines the term species richness? A the distribution of species over an area B the number of species in an area C the relative abun
November 2021, Paper 2, Q15 (1 mark): Biodiversity can be considered at different levels. An area of woodland habitat has a high Simpson’s Index of Diversity. Which of the following describes an are
November 2021, Paper 2, Q17(c)(i) (1 mark): State why the management of heather moorland is known as in situ conservation. [1]
November 2021, AS Paper 1, Q1 (1 mark): Which of the options, A to D, describes the role of CITES? A making conservation a part of normal farming practices B restricting the trade in individuals of en
November 2021, AS Paper 1, Q6 (1 mark): To determine the biodiversity of butterflies in a meadow, the number of different species of butterfly were sampled in a meadow on 12 consecutive days. The resu
November 2021, AS Paper 2, Q5(a)(i) (3 marks): Explain how a pitfall trap can be set up and used to sample invertebrate biodiversity. [3]
November 2021, AS Paper 2, Q5(a)(ii) (3 marks): The results for Area A are shown in the table below. 2 ⎛⎞ n n n = Number of Species organisms ⎝⎠ N N Common woodlouse 9 Black sexton beetle 6 Spotted wolf spide
November 2021, AS Paper 2, Q5(a)(iii) (1 mark): The students found the Simpson’s Index of Diversity for Area B to be 0.84. Compare the stability of the community living in Area B with that of the community li
November 2021, AS Paper 2, Q5(b)(i) (2 marks): Suggest two improvements you could make to these instructions. Improvement 1 Improvement 2 [2]
November 2021, AS Paper 2, Q5(b)(ii) (4 marks): Results of the four most abundant species from the study are shown in the graph below. 80 Key: 70 heather crowberry 60 bracken 50 cotton grass Percentage 40 cov
November 2021, AS Paper 2, Q5(c) (4 marks): Many birds found in moorland habitats, including the lapwing and curlew, are ‘red listed’ as species of high conservation concern. It is for this reason that ma
November 2020, Paper 2, Q18(a)(i) (2 marks): Calculate the proportion of genetic polymorphic gene loci of species B. 12] proportion =
November 2020, Paper 2, Q18(a)(ii) (3 marks): Evaluate the conclusion that species B shows greater genetic polymorphism than species A. .. [3]
November 2020, Paper 3, Q5(a) (3 marks): The ecologists sampled the area to estimate insect biodiversity. Describe how the ecologists should choose the number and locations of their samples to ensure t
November 2020, Paper 3, Q5(b)(i) (2 marks): Calculate the population sizes of the two insect species using each of the formulae below. Write your answers in the table. population size = n1 × n2 Lincoln es
November 2020, Paper 3, Q5(b)(ii) (2 marks): The Lincoln and Chapman formulae give different estimates for population size. Give two further conclusions about the difference in population estimates given b
November 2020, Paper 3, Q5(d) (2 marks): Conservation agreements can be national (within a particular country) or international. Three conservation agreements are listed in the table below. Place ticks
November 2020, AS Paper 1, Q5 (1 mark): The image below shows Dawlish Warren, which is a conservation area in the UK. Which of the following is an aesthetic reason for maintaining biodiversity in Dawl
November 2020, AS Paper 1, Q13 (1 mark): A student is investigating species richness of plants along a sand dune from the sea edge moving inland. They are testing the hypothesis that ‘species richness
June 2019, Paper 2, Q1 (1 mark): Which of the following is most likely to increase biodiversity? A captive breeding programmes B climate change C human population growth D monoculture Your answ
June 2019, Paper 2, Q18(c)(i) (3 marks): The students calculated the Simpson’s Index of Diversity (D) for the mature area to be 0.489. Use the information in Table 18 to work out the Simpson’s Index of
June 2019, Paper 2, Q18(c)(ii) (3 marks): Use the example of the students’ fieldwork to explain how biodiversity can be considered at different levels. [3] for the next question
June 2019, AS Paper 1, Q15 (1 mark): The sea marigold, Calendula maritima, is a rare species that is critically endangered and has been included in an ex situ conservation project. Which of the fol
June 2019, AS Paper 2, Q3(b)(i) (1 mark): Suggest one reason why the wildcat was hunted. [1]
June 2019, AS Paper 2, Q3(b)(ii) (6 marks): (ii)* Current estimates of the Scottish wildcat population vary. Recent reports by the Scottish Wildcat Association indicate that fewer than 100 individuals, po
June 2019, AS Paper 2, Q3(c)(i) (1 mark): An example of ex-situ conservation. [1]
June 2019, AS Paper 2, Q3(c)(ii) (1 mark): Helps to prevent the domestic and wild cats mixing freely with the Scottish wildcats in the haven. [1]
June 2019, AS Paper 2, Q3(c)(iii) (1 mark): Contributes to maintaining a healthy population in the wildcat haven. [1]
June 2019, AS Paper 2, Q3(c)(iv) (1 mark): Contributes to maintaining the genetic purity of the Scottish wildcat. [1]
June 2018, Paper 2, Q12 (1 mark): Turtle doves, Streptopelia turtur, were once common in farmland in the UK but their numbers have recently been in decline. Farmers can claim money from the UK g
June 2018, Paper 2, Q17(b)(i) (3 marks): Discuss whether the information in Fig. 17 supports the scientists’ claim. You should refer to the data in Fig. 17 in your answer. [3]
June 2018, Paper 2, Q17(b)(ii) (2 marks): Scientists working in the local area monitored water temperatures and populations of other water animals around the island between 1976 and 2010. Suggest two fu
June 2018, Paper 2, Q20(b)(i) (1 mark): State one way in which genetic diversity can be measured. [1]
June 2018, Paper 2, Q22(d) (2 marks): Listed below are three approaches, A, B and C, that can be taken to maintain biodiversity: A ex situ conservation B in situ conservation C preservation For each
June 2018, Paper 3, Q5(b) (2 marks): A scientist sampled the species of trees present in two different habitats containing Pinus glabra. The results of the sampling are shown in Table 5. Number of
June 2018, Paper 3, Q5(c)(ii) (3 marks): Suggest how the scientist could achieve the following during their investigation: Sample all stages of succession in the habitat Minimise sampling bias Sample i
June 2018, AS Paper 1, Q15 (1 mark): The Millennium Seed Bank has over two billion seeds in storage. Which of the options, A to D, describes the type of conservation carried out at the Millennium S
June 2018, AS Paper 1, Q25(d)(ii) (3 marks): For this investigation, the students randomly selected leaves from ten downy birch trees at varying distances from the river. Suggest three ways in which the st
June 2018, AS Paper 2, Q5(a)(i) (1 mark): Give one aim of CITES. [1]
June 2018, AS Paper 2, Q5(a)(ii) (2 marks): Between 1913 and 2013 the approximate worldwide population of living elephants dropped from 10 000 000 to 500 000. Calculate how many orders of magnitude smalle
June 2018, AS Paper 2, Q5(b) (2 marks): Fig. 5 shows the approximate percentages of elephants that were killed illegally in three different regions of Africa. Eastern Africa 100 80 number of 60 illega
June 2018, AS Paper 2, Q6(a)(i) (3 marks): Calculate the Simpson’s Index of Diversity for Upper End Meadow. Use the information in Table 6 and the formula: 2 n D = 1 − ∑ N n = number of organisms of this
June 2018, AS Paper 2, Q6(a)(ii) (1 mark): Name a piece of equipment that you could use for the random sampling of the plants shown in Table 6. [1]
June 2018, AS Paper 2, Q6(c) (1 mark): The students found 50 animals in a soil sample collected from Upper End Meadow and identified them as follows: • 2 click beetles • 24 leatherjackets • 23 meadow
June 2017, Paper 2, Q6 (1 mark): Which of the statements, A to D, best defines the term species evenness? A the number of species in an area B the relative abundance of each species in an area
June 2017, AS Paper 1, Q4 (1 mark): The genetic diversity of a population can be estimated using the following formula: proportion of polymorphic gene loci = number of polymorphic gene loci total
June 2017, AS Paper 1, Q13 (1 mark): Tropical rainforests have a very high biodiversity of plant species. Which of the statements, A to D, is an economic benefit of high biodiversity? A High plant
June 2017, AS Paper 2, Q5(a)(i) (2 marks): Calculate the total percentage decrease in the number of butterflies on farmland between 1992 and 2012. Show your working. Give your answer to the nearest whole
June 2017, AS Paper 2, Q5(a)(ii) (2 marks): Using the data given in Fig. 5, compare the changes in the number of butterflies on farmland and on woodland between 1992 and 2012. [2]
June 2017, AS Paper 2, Q5(a)(iii) (1 mark): Both habitats experienced the same weather conditions. Suggest a reason for the difference in the rates of decline in butterfly numbers in woodland and farmland
June 2017, AS Paper 2, Q5(a)(iv) (2 marks): A student made the following statement: ‘These data show that the change in butterfly numbers was caused by changes in weather conditions in England.’ Comment o
June 2017, AS Paper 2, Q5(a)(v) (1 mark): State one variable that scientists should control when carrying out surveys such as this. [1]
June 2017, AS Paper 2, Q5(b) (2 marks): Butterfly species in severe decline on farmland include gatekeeper, large skipper, small copper, wall brown, small tortoiseshell and white-letter hairstreak. Bu
June 2017, AS Paper 2, Q5(c)(i) (1 mark): What is the term given to this type of biodiversity? [1]
June 2017, AS Paper 2, Q5(c)(ii) (1 mark): Give one possible benefit to the species of this type of biodiversity. [1]
June 2016, AS Paper 1, Q9 (1 mark): Two different fields, field G and H, were sampled for three common species of wildflower. The results are shown below. Number of individuals Species Field G Fie
June 2016, AS Paper 1, Q23(c)(i) (2 marks): Suggest two reasons why this species is critically endangered in the wild. [2]
June 2016, AS Paper 1, Q23(c)(ii) (2 marks): The remaining populations of D. sumatrensis are all small and are scattered in isolated areas. These are factors that might speed up the extinction of the speci
June 2016, AS Paper 1, Q23(c)(iii) (1 mark): Captive breeding programmes with D. sumatrensis have been unsuccessful. Suggest one other way in which zoos can contribute to the conservation of the Sumatran r

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