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Population size and ecosystems: Eduqas A‑Level Biology questions

Every Eduqas A-Level Biology exam question on 1.5 Population size and ecosystems, 2016–2025, with its mark scheme and examiner’s report.

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2,061 questions

  1. Q4(a)(ii)

    June 2025 · Component 1

    4 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2025 Component 1, question 4(a)(ii): The threshold for climate change has been crossed. This has been linked to human activities, including deforestation. With reference to the role of photoautotro

  2. Q4(b)(i)

    June 2025 · Component 1

    1 mark1.5 Population size and ecosystems
    The whole paper ↗
    June 2025 Component 1, question 4(b)(i): State what the arrows represent in Image 4.2 [1]

  3. Q4(b)(ii)

    June 2025 · Component 1

    2 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2025 Component 1, question 4(b)(ii): Identify the following in Image 4.2: I. an organism that is both a herbivore and a detritivore [1] II. an omnivore [1]

  4. Q4(b)(iii)

    June 2025 · Component 1

    1 mark1.5 Population size and ecosystems
    The whole paper ↗
    June 2025 Component 1, question 4(b)(iii): Identify the original source of the energy transferred between organisms. [1]

  5. Q6(a)(ii)

    June 2025 · Component 1

    2 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2025 Component 1, question 6(a)(ii): Table 6.1 lists three factors that could affect the size of a population. Table 6.1 Density- Density- Factor Abiotic Biotic dependent independent Atmospheric te

  6. Q6(b)(ii)

    June 2025 · Component 1

    3 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2025 Component 1, question 6(b)(ii): Under optimal conditions, African elephants have a generation time of 22 years. This is the time taken for a population to double in number. Generation time (G)

  7. Q6(b)(iii)

    June 2025 · Component 1

    1 mark1.5 Population size and ecosystems
    The whole paper ↗
    June 2025 Component 1, question 6(b)(iii): One conservation method used has been to set up enclosed areas where elephants are protected. If the area is not enclosed, it could lead to a decrease in the ti

  8. Q7

    June 2025 · Component 1

    9 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2025 Component 1, question 7: Succession is the change in structure and species composition of a community over time. Primary succession from bare rock to a mature community can take hundred

  9. Q6(a)(i)

    June 2025 · Component 2

    1 mark1.5 Population size and ecosystems
    The whole paper ↗
    June 2025 Component 2, question 6(a)(i): Explain why random numbers were generated in Step 2. [1] The results for the two sites are shown in Table 6.1. Table 6.1 Mean number of plants per quadrat Plant

  10. Q6(b)

    June 2025 · Component 2

    4 marks1.5 Population size and ecosystems2.1 All organisms are related through their evolutionary history
    The whole paper ↗
    June 2025 Component 2, question 6(b): To preserve biodiversity the local council decided to use Site 1 However, environmentalists queried the validity of the method used to gain the results. Identif

  11. Q2(a)(ii)

    June 2024 · Component 1

    2 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2024 Component 1, question 2(a)(ii): Plant productivity can be expressed as GPP or NPP. Explain why only NPP is available to consumers. [2]

  12. Q2(a)(iii)

    June 2024 · Component 1

    1 mark1.5 Population size and ecosystems
    The whole paper ↗
    June 2024 Component 1, question 2(a)(iii): Human population density is increasing exponentially. Explain what is meant by the term exponential growth. [1]

  13. Q2(a)(iv)

    June 2024 · Component 1

    1 mark1.5 Population size and ecosystems
    The whole paper ↗
    June 2024 Component 1, question 2(a)(iv): State the term used to describe the phrase: ‘… maximum human population that can be sustained by current plant productivity levels.’ [1]

  14. Q2(b)(i)

    June 2024 · Component 1

    2 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2024 Component 1, question 2(b)(i): Deserts and arctic-alpine regions have very low NPP per km2. Identify one density-independent factor that accounts for the very low NPP per km2 of both regions.

  15. Q2(c)(iii)

    June 2024 · Component 1

    3 marks1.6 Human impact on the environment1.5 Population size and ecosystems
    The whole paper ↗
    June 2024 Component 1, question 2(c)(iii): Annual consumption of animal products by humans in 1987 was estimated at 0.15 Pg. Estimated global consumption of plants by livestock in 1987 was 2.2 Pg. It has

  16. Q5(a)(ii)

    June 2024 · Component 1

    2 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2024 Component 1, question 5(a)(ii): climate change. [2]

  17. Q5(b)(i)

    June 2024 · Component 1

    1 mark1.5 Population size and ecosystems
    The whole paper ↗
    June 2024 Component 1, question 5(b)(i): State what is meant by the term climax community. [1]

  18. Q5(b)(ii)

    June 2024 · Component 1

    5 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2024 Component 1, question 5(b)(ii): Suggest how the following abiotic factors would have changed following the establishment of the avocado plantation. Explain your answers. I. soil moisture conte

  19. Q5(b)(iii)

    June 2024 · Component 1

    4 marks1.5 Population size and ecosystems2.1 All organisms are related through their evolutionary history
    The whole paper ↗
    June 2024 Component 1, question 5(b)(iii): Outline a method that could be used to estimate and compare the plant biodiversity of the original forest and the avocado plantation. [4]

  20. Q5(c)(ii)

    June 2024 · Component 2

    2 marks1.5 Population size and ecosystems
    The whole paper ↗
    June 2024 Component 2, question 5(c)(ii): Suggest two advantages to plants that grow from seeds after a forest fire. [2]
All 92 questions on Population size and ecosystems, as a list
  1. June 2025, Component 1, Q4(a)(ii) (4 marks): The threshold for climate change has been crossed. This has been linked to human activities, including deforestation. With reference to the role of photoautotro
  2. June 2025, Component 1, Q4(b)(i) (1 mark): State what the arrows represent in Image 4.2 [1]
  3. June 2025, Component 1, Q4(b)(ii) (2 marks): Identify the following in Image 4.2: I. an organism that is both a herbivore and a detritivore [1] II. an omnivore [1]
  4. June 2025, Component 1, Q4(b)(iii) (1 mark): Identify the original source of the energy transferred between organisms. [1]
  5. June 2025, Component 1, Q6(a)(ii) (2 marks): Table 6.1 lists three factors that could affect the size of a population. Table 6.1 Density- Density- Factor Abiotic Biotic dependent independent Atmospheric te
  6. June 2025, Component 1, Q6(b)(ii) (3 marks): Under optimal conditions, African elephants have a generation time of 22 years. This is the time taken for a population to double in number. Generation time (G)
  7. June 2025, Component 1, Q6(b)(iii) (1 mark): One conservation method used has been to set up enclosed areas where elephants are protected. If the area is not enclosed, it could lead to a decrease in the ti
  8. June 2025, Component 1, Q7 (9 marks): Succession is the change in structure and species composition of a community over time. Primary succession from bare rock to a mature community can take hundred
  9. June 2025, Component 2, Q6(a)(i) (1 mark): Explain why random numbers were generated in Step 2. [1] The results for the two sites are shown in Table 6.1. Table 6.1 Mean number of plants per quadrat Plant
  10. June 2025, Component 2, Q6(b) (4 marks): To preserve biodiversity the local council decided to use Site 1 However, environmentalists queried the validity of the method used to gain the results. Identif
  11. June 2024, Component 1, Q2(a)(ii) (2 marks): Plant productivity can be expressed as GPP or NPP. Explain why only NPP is available to consumers. [2]
  12. June 2024, Component 1, Q2(a)(iii) (1 mark): Human population density is increasing exponentially. Explain what is meant by the term exponential growth. [1]
  13. June 2024, Component 1, Q2(a)(iv) (1 mark): State the term used to describe the phrase: ‘… maximum human population that can be sustained by current plant productivity levels.’ [1]
  14. June 2024, Component 1, Q2(b)(i) (2 marks): Deserts and arctic-alpine regions have very low NPP per km2. Identify one density-independent factor that accounts for the very low NPP per km2 of both regions.
  15. June 2024, Component 1, Q2(c)(iii) (3 marks): Annual consumption of animal products by humans in 1987 was estimated at 0.15 Pg. Estimated global consumption of plants by livestock in 1987 was 2.2 Pg. It has
  16. June 2024, Component 1, Q5(a)(ii) (2 marks): climate change. [2]
  17. June 2024, Component 1, Q5(b)(i) (1 mark): State what is meant by the term climax community. [1]
  18. June 2024, Component 1, Q5(b)(ii) (5 marks): Suggest how the following abiotic factors would have changed following the establishment of the avocado plantation. Explain your answers. I. soil moisture conte
  19. June 2024, Component 1, Q5(b)(iii) (4 marks): Outline a method that could be used to estimate and compare the plant biodiversity of the original forest and the avocado plantation. [4]
  20. June 2024, Component 2, Q5(c)(ii) (2 marks): Suggest two advantages to plants that grow from seeds after a forest fire. [2]
  21. June 2024, Component 2, Q5(d) (3 marks): When areas of forest are burned, nitrogen oxides are released into the air in the smoke. These dissolve in rainwater to produce nitrites. After a forest fire, l
  22. June 2023, Component 1, Q4(a)(ii) (4 marks): Use your knowledge of the nitrogen cycle to explain the sequence of the appearance of ammonia, nitrite and nitrate as shown in Graph 4. [4]
  23. June 2023, Component 1, Q4(a)(iii) (2 marks): Explain why the water was continually aerated. [2]
  24. June 2023, Component 1, Q4(a)(iv) (1 mark): Suggest a possible explanation for the change in nitrate concentration at day 45. [1]
  25. June 2023, Component 1, Q4(b)(i) (2 marks): Suggest what would happen to the concentration of nitrate ions if plants were grown in the aquarium. Explain why this would happen. [2]
  26. June 2023, Component 1, Q4(b)(ii) (3 marks): Suggest why the concentration of nitrogen containing compounds may increase if too many fish are introduced into an aquarium. [3]
  27. June 2023, Component 1, Q6(a)(i) (2 marks): During motorway construction the verges are usually left as bare soil. Explain why subsequent colonisation of these verges can be described as secondary success
  28. June 2023, Component 1, Q6(a)(ii) (4 marks): Long-term management of motorway verges often involves cutting the vegetation back to ground level in early Spring and again in August / September. I. Explain w
  29. June 2023, Component 1, Q6(b)(i) (1 mark): Describe how the grid could have been used to reduce bias when pl
  30. June 2023, Component 1, Q6(b)(ii) (1 mark): Suggest why different coloured traps were used. [1]
  31. June 2023, Component 1, Q6(b)(iii) (2 marks): Suggest one ethical and one ecological concern regarding the method used to store and identify the bees and wasps collected. [2] ethical ecological
  32. June 2023, Component 1, Q7 (9 marks): Graph 7 shows how the human population has changed since 1800. It also shows three projections of how the world population might change by the end of the 21st c
  33. June 2023, Component 2, Q1(b)(i) (2 marks): Describe and explain the evidence from Image 1.2 that shows that nitrogen fixation is not taking place in this cyanobacterium. [2]
  34. June 2022, Component 1, Q3(a)(i) (1 mark): State what is represented by the following abbreviations: [1] GPP NPP
  35. June 2022, Component 1, Q3(a)(ii) (2 marks): Using figures from Image 3.1, calculate the following: I. The GPP of the producers. [1] GPP = kJ m–2 year –1 II. The NPP of the producers. [1] NPP = kJ m–2 year
  36. June 2022, Component 1, Q3(b)(i) (2 marks): Apart from dead tissue, name two other processes carried out by herbivores and carnivores that would also transfer energy to decomposers at Y. [2] I. II.
  37. June 2022, Component 1, Q3(b)(ii) (2 marks): Using figures from Image 3.1, calculate the secondary productivity of the herbivores and use this to calculate R for this trophic level. [2] Secondary productiv
  38. June 2022, Component 1, Q3(b)(iii) (1 mark): State two types of organisms which act as decomposers. [1]
  39. June 2022, Component 1, Q3(b)(iv) (4 marks): In the UK, most plants die or shed their leaves in the Autumn. Using your knowledge of the nitrogen cycle, explain why you would expect the nitrogen content of
  40. June 2022, Component 1, Q3(c)(i) (1 mark): A forest is often the final stage in the development of an ecosystem which can then exist for hundreds of years. State the term used to describe the last stage
  41. June 2022, Component 1, Q3(c)(ii) (2 marks): With reference to the terms GPP and R, explain why the productivity of an ecosystem can be expressed in terms of absorption of carbon dioxide or by the release
  42. June 2022, Component 1, Q3(c)(iii) (3 marks): With reference to the information provided and your knowledge of succession, conclude why Net Ecosystem Productivity eventually approaches zero. [3]
  43. June 2022, Component 1, Q5(b) (3 marks): Grasslands contain a wide variety of flowering plants which produce flowers at different times of the year. The biodiversity of these grasslands decreases when
  44. June 2022, Component 1, Q5(c)(i) (2 marks): Each area was divided into a grid and a random number generator used. [2]
  45. June 2022, Component 1, Q5(c)(ii) (2 marks): Area B was not seeded with yellow-rattle seeds. [2]
  46. June 2022, Component 1, Q5(c)(iii) (2 marks): The experiment was conducted several times on grassland with the same species of fast-growing grass. [2]
  47. Autumn 2021, Component 1, Q4(a) (1 mark): State the meaning of the word fixed as used in this context. [1]
  48. Autumn 2021, Component 1, Q4(b)(i) (3 marks): Name the nitrifying bacteria and describe how they produce a source of electrons and protons (H+). [3]
  49. Autumn 2021, Component 1, Q5(a)(i) (3 marks): Calculate the percentage change in the number of breeding pairs of redshank in Area 2 if the population in 1983 was 1 288 breeding pairs and in 2000 it was 760
  50. Autumn 2021, Component 1, Q5(a)(ii) (2 marks): With reference to the data in table 5.2 and the information provided, evaluate the conclusion that hedgehogs are the main reason for the decline in wading bird
  51. Autumn 2021, Component 1, Q5(a)(iii) (2 marks): Explain one advantage and one disadvantage of expressing the change in the number of breeding pairs as a percentage. [2]
  52. Autumn 2021, Component 1, Q5(a)(iv) (2 marks): State two factors which could have allowed a very large population of hedgehogs to have been produced from the original seven individuals. [2] I. II.
  53. Autumn 2021, Component 1, Q5(b)(i) (2 marks): fenced. These acted as control areas. • Egg loss in the fenced and unfenced areas was compared and the type of predator causing the egg loss recorded. (i) State
  54. Autumn 2021, Component 1, Q7(a)(i) (2 marks): Explain what is meant by a climax community and why regrowth of a kelp forest is an example of secondary succession. [2]
  55. Autumn 2021, Component 1, Q7(a)(ii) (4 marks): In addition to sea urchins, sea otters also eat crabs and shellfish. Using your knowledge of predator prey relationships, suggest how the presence of sea otters
  56. Autumn 2021, Component 1, Q7(a)(iii) (3 marks): Explain why scientists consider that the destruction of sea otter populations could contribute to an increase in global warming. [3]
  57. Autumn 2021, Component 2, Q1(b)(i) (2 marks): Explain why the ecologists worked upstream from the first sample. [2]
  58. Autumn 2021, Component 2, Q1(b)(ii) (1 mark): Suggest why the quadrats were placed in the middle of each stream. [1] Table 1.3 below shows the mean number of Families in the different Orders of insects per
  59. Autumn 2021, Component 2, Q7(a)(i) (1 mark): State the main type of competition present: [1] I. at 800 m II. between 1 000 m and 1 250 m
  60. Autumn 2021, Component 2, Q7(a)(ii) (2 marks): Identify three density dependent factors which could affect the distribution and population densities of these bird species between 1 000 m and 1 250 m above se
  61. Autumn 2020, Component 1, Q4(a) (3 marks): With reference to human activity, explain the shape of the estimated population graph shown in image 4.1 between the following dates: [3] 1850 to 1950; 1970 to
  62. Autumn 2020, Component 1, Q4(d) (3 marks): Bottom trawling involves dragging very large weighted nets along the sea bed. The heavy equipment used in bottom trawling destroys the seabed, as shown in image
  63. Autumn 2020, Component 1, Q4(e) (2 marks): Planetary boundaries attempt to quantify and set a safe limit for the environmental impact of human activity. The boundary limit for CO2 in the atmosphere was s
  64. Autumn 2020, Component 1, Q7 (9 marks): The diagram below shows the flow of energy through an ecosystem. Sun 1 × 106 solar energy autotroph heterotroph heterotroph heterotroph 8000 800 160 32 Figures
  65. June 2019, Component 1, Q1(b)(i) (1 mark): Suggest a unit for time on the x-axis. [1]
  66. June 2019, Component 1, Q1(b)(ii) (1 mark): State what is represented by line E. [1]
  67. June 2019, Component 1, Q1(c)(i) (3 marks): Identify phases A, B and D labelled on the graph and explain what is happening to the yeast population in each phase. [3] A B D
  68. June 2019, Component 1, Q1(c)(ii) (2 marks): Suggest one factor that has caused the change in the shape of the graph in phase C and suggest what you would expect to have happened to the population at the e
  69. June 2019, Component 1, Q1(e) (2 marks): A knowledge of population numbers is very important in ecology so that changes can be detected quickly. To estimate the populations of mobile animals, a method
  70. June 2019, Component 1, Q1(f) (2 marks): Suggest two assumptions that must be made when using this technique to estimate snail population numbers. [2]
  71. June 2019, Component 1, Q5(a) (3 marks): State the term used to describe the I. process by which the saltmarsh community is formed. [1] II. first organisms to colonise the mud. [1] III. the final group
  72. June 2019, Component 1, Q5(b) (6 marks): A saltmarsh is an extreme environment for organisms trying to survive. Using the information given, identify three abiotic factors which cause this to be an ext
  73. June 2019, Component 1, Q5(c)(i) (1 mark): State why denitrification is classed as a biotic factor. [1]
  74. June 2019, Component 1, Q5(c)(ii) (3 marks): Using the information given and your own knowledge, identify two factors affecting denitrification. Explain each of your answers. [3]
  75. June 2019, Component 1, Q5(d) (5 marks): Describe a practical method which you could carry out on the saltmarsh to investigate the change in vegetation over time. [5]
  76. June 2019, Component 1, Q6(b) (3 marks): In areas where Red Kites were absent and then re-introduced the numbers increased much more rapidly than in areas where they were already established. Explain t
  77. June 2019, Component 1, Q7 (9 marks): Since the beginning of the Industrial Revolution (250 years ago), carbon dioxide concentration in the atmosphere has risen from about 280 parts per million to 4
  78. June 2019, Component 2, Q3(a) (3 marks): Explain the steps the students should have taken to ensure their sampling methods produced representative totals. [3]
  79. June 2018, Component 1, Q3(a) (2 marks): Explain how the low levels of nitrates are brought about in these meadows. [2]
  80. June 2018, Component 1, Q3(b) (3 marks): Explain fully how the change in agricultural practices has led to the loss of this type of meadow. [3]
  81. June 2018, Component 1, Q3(d)(i) (3 marks): Describe the technique you would use to carry out an assessment of the abundance of these two species across a moderately trampled footpath. [3]
  82. June 2018, Component 1, Q3(d)(ii) (4 marks): Using the information in the table, predict which species would be found mainly in the centre of the trampled path and which species is found mainly at the edge
  83. June 2018, Component 1, Q3(e)(i) (3 marks): Why does a food chain usually sustain no more than six energy transfers? Explain why it would be more energy efficient to produce food in the form of corn, soyb
  84. June 2018, Component 1, Q3(e)(ii) (2 marks): Explain why most warm-blooded organisms have to eat more often than cold- blooded organisms to get the energy they need for survival. [2]
  85. June 2018, Component 2, Q5(a) (4 marks): Factors affecting population size are described as density dependent or density independent. Use the graph to identify when density dependent and density indepe
  86. June 2018, Component 3, Q6(c) (3 marks): Until recently, the main species of Erwinia that caused soft-rot in the UK was E. carotovora. This species spreads rapidly in the cool, wet conditions usually f
  87. June 2017, Component 1, Q3(c) (3 marks): Explain how deforestation can directly affect the planetary boundary for climate change. [3]
  88. June 2017, Component 1, Q7(a) (2 marks): What are the main advantages of using hair-tube surveys to determine population numbers of the two species of squirrel? [2] Another type of survey involves the
  89. June 2017, Component 1, Q7(b) (3 marks): Describe how you would set up a transect so that the distribution of cone cores could be easily assessed. [3]
  90. June 2017, Component 1, Q7(c)(i) (2 marks): Calculate the total energy consumed by the squirrels from the cones. [2] Total energy consumed from the cones = kJ
  91. June 2017, Component 1, Q7(c)(ii) (2 marks): Using your answer from (i) and the information above, calculate the total energy consumed in the area per hectare per day. (There are 10 000 m2 in 1 hectare.) [
  92. June 2017, Component 1, Q7(c)(iii) (1 mark): The average adult red squirrel consumes 550 kJ per day. Calculate the estimated density of squirrels for the woodland. [1] Squirrels per hectare =

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