plumiEcosystems, distribution and succession: Edexcel International A Level Biology questions
Every Edexcel International A Level Biology exam question on Ecosystems, distribution and succession (specification points 5.11–5.15), 2019–2025, with its mark scheme and examiner’s report.
Paper
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Exam
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Calculations
Q1(a)
The whole paper ↗Your answerQ1(d)
The whole paper ↗Q3(a)(i)
The whole paper ↗Q3(a)(ii)
The whole paper ↗Q3(a)(iii)
The whole paper ↗Q3(b)
The whole paper ↗Q2(a)
The whole paper ↗Q2(c)
The whole paper ↗Q5(a)
The whole paper ↗Q5(b)
The whole paper ↗Your answerQ5(c)
The whole paper ↗Q4(b)
The whole paper ↗Your answerQ4(c)(i)
The whole paper ↗Your answerQ4(c)(ii)
The whole paper ↗Q6(a)(i)
The whole paper ↗Q6(a)(ii)
The whole paper ↗Q6(a)(iii)
The whole paper ↗Q6(b)
The whole paper ↗Q6(b)(ii)
The whole paper ↗Q4(c)(i)
The whole paper ↗Your answer
All 54 questions on Ecosystems, distribution and succession, as a list
- June 2025, Unit 4, Q1(a) (1 mark): Which term describes the events that took place to change the extinct volcano into a habitat for many species? (1) A entomology B evolution C speciation D succe
- January 2025, Unit 4, Q1(d) (1 mark): Forests are examples of ecosystems. State what is meant by the term ecosystem. (1)
- January 2025, Unit 4, Q3(a)(i) (1 mark): In 1863, there were 150 000 hares. Calculate how many times more hares there were than lynx. (1) Answer
- January 2025, Unit 4, Q3(a)(ii) (2 marks): Graph 2 shows part of graph 1. Sketch a line on graph 2 to show the likely changes in the numbers of hares from 1855 to 1880. Graph 2 Number of animals lynx 184
- January 2025, Unit 4, Q3(a)(iii) (3 marks): Explain the changes in the numbers of lynx and hares. (3)
- January 2025, Unit 4, Q3(b) (2 marks): In many ecosystems, the relationship between one predator species and one prey species is less predictable. Suggest two reasons why this relationship is not alw
- January 2025, Unit 6, Q2(a) (4 marks): Describe a sampling method that could be used to collect valid data to investigate this observation. (4)
- January 2025, Unit 6, Q2(c) (2 marks): The analysis showed that there is a positive relationship between the closeness of the mounds and the fruiting of the trees. The soil near termite mounds has an
- October 2024, Unit 4, Q5(a) (1 mark): State the meaning of the term succession. (1)
- October 2024, Unit 4, Q5(b) (1 mark): Which of the following describes a habitat? (1) A a group of interacting organisms B a place that meets the environmental conditions an organism needs to survi
- October 2024, Unit 4, Q5(c) (6 marks): Succession takes place as a glacier retreats. As the ice melts, bare rock is exposed. The graph shows the changes in the numbers of three different types of pla
- January 2024, Unit 4, Q4(b) (1 mark): Which letter on the diagram indicates the location of pioneer species only? (1) A P B Q C R D S
- January 2024, Unit 4, Q4(c)(i) (1 mark): Which term describes the changes in soil conditions and organisms with time? (1) A anthropogenic B evolution C speciation D succession
- January 2024, Unit 4, Q4(c)(ii) (6 marks): The table shows the soil carbon : nitrogen ratio in ground exposed by a retreating glacier. Length of time that the ground Carbon : nitrogen ratio in has been e
- January 2024, Unit 4, Q6(a)(i) (2 marks): Habitat (2)
- January 2024, Unit 4, Q6(a)(ii) (2 marks): Population (2)
- January 2024, Unit 4, Q6(a)(iii) (2 marks): Community (2)
- January 2024, Unit 4, Q6(b) (3 marks): Explain how the niche of the slender loris affects the distribution and abundance of the Bengal tigers. (3)
- October 2023, Unit 4, Q6(b)(ii) (2 marks): The scientists used the data to predict a relationship between the length of the young lizards and the percentage change in abundance of lizards over the 12 yea
- June 2023, Unit 4, Q4(c)(i) (1 mark): Which sequence shows the succession of bacteria during the development of a giant panda? (1) A Clostridium → Streptococcus → Escherichia and Shigella B Escheric
- June 2023, Unit 6, Q2(a) (1 mark): Suggest one possible benefit to cactus plants of growing near mimosa trees. (1)
- June 2023, Unit 6, Q2(c)(i) (3 marks): An odds ratio can be used to determine if the presence of mimosa trees has an effect on the presence of the cactus plants. Calculate an odds ratio using the fol
- June 2023, Unit 6, Q2(c)(ii) (1 mark): The table shows how the odds ratio can be used in this investigation. Odds ratio Presence of mimosa trees Reduces the likelihood of cactus plants being present
- June 2023, Unit 6, Q3(f) (2 marks): Pyrethrum is applied to fruit crops growing in fields. Suggest two reasons why applying pyrethrum to fruit crops in fields might not reduce damage to fruits. (2
- January 2023, Unit 4, Q6(b)(ii) (1 mark): The zone of tolerance is the range of temperatures that a fish could survive at for longer than 5000 minutes. Which two biotic factors could cause the fish to d
- January 2023, Unit 6, Q4(a) (3 marks): Describe preliminary practical work that you might undertake to find a suitable method for observing these grasshoppers to provide quantitative results. (3)
- January 2023, Unit 6, Q4(b) (8 marks): Devise a detailed method, including how you would control and monitor important variables. (8)
- January 2023, Unit 6, Q4(d) (3 marks): Suggest three limitations of your proposed method. (3)
- October 2022, Unit 4, Q9(d) (6 marks): Forests, shrublands and grasslands are three types of ecosystem. Biotic and abiotic factors affect how much biomass is stored in the roots of plants. The graphs
- June 2022, Unit 4, Q7(a) (1 mark): The number of Tasmanian devils is estimated to have fallen from 150 000 in the mid‑1990s to 25 000 in 2020. Calculate the percentage decrease in the number of T
- June 2022, Unit 4, Q7(b)(i) (6 marks): Explain the results of these two studies. Use the information in the table and the graph to support your answer. (6)
- June 2022, Unit 4, Q7(b)(ii) (4 marks): Explain what other biotic factors could have affected the results from the two different regions of Tasmania, in the second investigation. (4)
- June 2022, Unit 4, Q8(a)(i) (3 marks): Describe three characteristics of pioneer species. (3)
- June 2022, Unit 4, Q8(a)(ii) (2 marks): Explain why succession occurs in stages. (2)
- January 2022, Unit 4, Q7(a)(i) (1 mark): State the meaning of the term population, as it has been used in this context. (1)
- January 2022, Unit 6, Q3(e) (2 marks): Explain why it may not be reasonable to draw valid conclusions from the results of this investigation. (2)
- October 2021, Unit 6, Q3(a) (2 marks): Identify one risk you might encounter when carrying out this investigation and how you could reduce this risk. (2) Risk How to reduce this risk
- October 2021, Unit 6, Q3(d) (3 marks): Describe three improvements that could be made to this investigation. (3)
- October 2021, Unit 6, Q3(e)(i) (1 mark): Suggest one abiotic factor that might cause the difference in length of the marram grass leaves at these positions on the dune. (1)
- October 2021, Unit 6, Q3(e)(ii) (3 marks): Describe how this factor could be measured to produce valid comparisons in this investigation. (3)
- June 2021, Unit 4, Q1(a)(i) (1 mark): Which row of the table shows the type of factor that affected the plant species in two of these habitats? (1) Cutting the field regularly Competition with trees
- June 2021, Unit 4, Q1(a)(iii) (2 marks): Suggest reasons for the differences in the mean number of plant species in fields cut regularly and in fields not cut. (2)
- June 2021, Unit 4, Q3(a)(i) (2 marks): Habitat (2)
- June 2021, Unit 4, Q3(a)(ii) (2 marks): Population (2)
- June 2021, Unit 4, Q3(a)(iii) (2 marks): Community (2)
- June 2021, Unit 4, Q3(a)(iv) (2 marks): Niche (2)
- June 2021, Unit 4, Q7(a)(i) (1 mark): The pH of a solution is a measure of the concentration of hydrogen ions in that solution. It is a log scale e.g. a solution of pH 5 contains 10-5 mol dm-3 of hy
- June 2021, Unit 4, Q7(a)(ii) (1 mark): Calculate the percentage increase in the number of plant species on the grey dune compared with the fore dune. (1) Answer %
- June 2021, Unit 4, Q7(a)(iii) (6 marks): Explain the changes in these sand dunes with distance from the sea. Use the information in the table to support your answer. (6)
- October 2020, Unit 4, Q9(b)(i) (2 marks): Calculate the percentage of moose that have 50 000 or more ticks on their bodies. (2) Answer %
- January 2020, Unit 4, Q1(b)(i) (1 mark): State the meaning of the term ecosystem. (1)
- January 2020, Unit 4, Q6(a) (3 marks): The diagram shows the distribution of two types of barnacle, Chthamalus and Balanus, on a rock. highest level the seawater reaches Key Chthamalus Balanus seawat
- January 2020, Unit 4, Q6(b)(i) (4 marks): Comment on the reliability of the conclusions that can be drawn from this study. (4)
- January 2020, Unit 4, Q6(b)(ii) (4 marks): Describe how this study could be carried out in a laboratory. (4)
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