Ecosystems: OCR GCSE Combined Science A questions

Every OCR GCSE Combined Science A exam question on B4.1 Ecosystems, 2018–2025, with its mark scheme and examiner’s report.

All 90 questions on Ecosystems, as a list

June 2025, Biology Paper 2 Foundation, Q10 (1 mark): Which pathway shows how nitrates are used by plants to make proteins? A Nitrates amino acids proteins B Nitrates carbohydrates proteins C Nitrates DNA proteins
June 2025, Biology Paper 2 Foundation, Q11(a)(i) (1 mark): A primary consumer. [1]
June 2025, Biology Paper 2 Foundation, Q11(a)(ii) (1 mark): An abiotic component. [1]
June 2025, Biology Paper 2 Foundation, Q11(b) (2 marks): Describe the role of grass as a producer in this food chain. [2]
June 2025, Biology Paper 2 Foundation, Q11(c) (2 marks): Organisms depend on each other for survival. This is called interdependence. Fig. 11.2 shows a buffalo and some oxpeckers. Fig. 11.2 © animals.mom.com, mom.com.
June 2025, Biology Paper 2 Foundation, Q13(a)(i) (2 marks): Complete the two labels in the diagram to identify the processes involved in the carbon cycle. CO2 in the atmosphere Combustion Dead organic material Fossils an
June 2025, Biology Paper 2 Foundation, Q13(a)(ii) (2 marks): Explain the role of decomposers in the carbon cycle. [2]
June 2025, Biology Paper 2 Foundation, Q13(a)(iii) (1 mark): Decomposition can take place aerobically or anaerobically. What is meant by the term anaerobically? [1]
June 2025, Biology Paper 2 Foundation, Q13(b) (1 mark): The graph shows the changes in carbon dioxide levels in the atmosphere during a year. Atmospheric carbon dioxide (parts per million) Jan April July Oct Jan Mont
June 2025, Biology Paper 2 Foundation, Q15(a)(i) (1 mark): Calculate the mean dandelion height for the soil at pH 10. Write your answer in the table. [1]
June 2025, Biology Paper 2 Foundation, Q15(a)(ii) (1 mark): The student identifies an outlier in the results. Tick (✓) one correct set of results to identify the outlier. Soil pH Dandelion height Outlier 2 result 2 6 res
June 2025, Biology Paper 2 Foundation, Q15(b) (3 marks): Plot a graph of the student’s mean results. Choose appropriate scales. [3]
June 2025, Biology Paper 2 Foundation, Q15(c) (1 mark): Draw a curve of best fit. [1] Mean dandelion height (cm) Soil pH
June 2025, Biology Paper 2 Foundation, Q15(d) (2 marks): What conclusions can be made from the student’s results? Include data in your answer. [2]
June 2025, Biology Paper 8 Higher, Q2 (1 mark): Which pathway shows how nitrates are used by plants to make proteins? A Nitrates amino acids proteins B Nitrates carbohydrates proteins C Nitrates DNA proteins
June 2025, Biology Paper 8 Higher, Q3 (1 mark): Which term describes the interaction between the biotic and abiotic factors in the environment? A Community B Ecosystem C Habitat D Species Your answer [1]
June 2025, Biology Paper 8 Higher, Q4 (1 mark): Water is recycled in the environment. Which process increases the level of water in the atmosphere? A Condensation B Precipitation C Translocation D Transpirati
June 2025, Biology Paper 8 Higher, Q15(a) (1 mark): Bacteria and yeast are in an interdependent relationship. What is the name of this type of relationship? [1]
June 2024, Biology Paper 2 Foundation, Q4 (1 mark): Which word describes all the physical features and living organisms in an area? A Community B Ecosystem C Habitat D Interdependence Your answer [1]
June 2024, Biology Paper 2 Foundation, Q6 (1 mark): Which process is required to recycle both carbon and nitrogen? A Condensation B Decomposition C Photosynthesis D Precipitation Your answer [1]
June 2024, Biology Paper 2 Foundation, Q14(c) (2 marks): Moisture content is one abiotic factor that affects plants. State two other abiotic factors that affect plant growth. 1 2 [2]
June 2024, Biology Paper 2 Foundation, Q15 (6 marks): 15* The graph shows the changes in population of a predator and its prey. Gazelle Population Lions Time Describe and explain the trends in the graph. Identify t
June 2024, Biology Paper 8 Higher, Q6 (1 mark): Which row shows the correct order of some processes in the water cycle? A Condensation evaporation precipitation condensation B Condensation precipitation evapo
June 2024, Biology Paper 8 Higher, Q14(b) (3 marks): Moisture content is one factor that affects plants. The amount of microorganisms in the soil can also affect plant growth. Explain why soil microorganisms are i
June 2024, Biology Paper 8 Higher, Q14(c) (1 mark): Why are microorganisms described as a biotic factor and soil moisture as an abiotic factor? [1]
June 2023, Biology Paper 2 Foundation, Q6 (1 mark): Which row shows the correct levels of organisation in an ecosystem? Smallest Largest A community population species ecosystem B community species population eco
June 2023, Biology Paper 2 Foundation, Q10 (1 mark): The graph shows the changing population of one species in a habitat. Number of organisms in population 1980 1990 2000 2010 2020 Year Predict the years when this
June 2023, Biology Paper 2 Foundation, Q12(a)(i) (1 mark): Which is a correct statement about these results? Tick (3) one box. Temperatures > 4 °C stop mould decomposing the bread. Temperatures = to –18 °C stop mould de
June 2023, Biology Paper 2 Foundation, Q12(a)(ii) (2 marks): Look at the results for 20 °C. Calculate the increase in area covered by mould between day 5 and day 10. Increase in percentage area covered = % [2]
June 2023, Biology Paper 2 Foundation, Q12(b) (2 marks): Suggest how the student could change their method to investigate the effect of moisture on decomposition. [2]
June 2023, Biology Paper 2 Foundation, Q12(c) (2 marks): Decomposers release carbon from decaying plant material as part of the carbon cycle. Complete the table to describe two different processes in the carbon cycle.
June 2023, Biology Paper 2 Foundation, Q12(d)(i) (2 marks): Complete the diagram. Use the words from the list. Collection Condensation Evaporation Precipitation Respiration Transpiration [2]
June 2023, Biology Paper 2 Foundation, Q12(d)(ii) (2 marks): Explain why transpiration is important to the plant communities in an ecosystem. [2]
June 2023, Biology Paper 2 Foundation, Q13(a) (1 mark): Which word describes the interdependence between the hummingbird and the flower? Put a ring around the correct answer. competition mutualism parasitism predatio
June 2023, Biology Paper 8 Higher, Q2 (1 mark): The graph shows the changing population of one species in a habitat. Number of organisms in population 1980 1990 2000 2010 2020 Year Predict the years when this
June 2023, Biology Paper 8 Higher, Q3 (1 mark): Which process in the water cycle returns water to the land from the atmosphere? A Condensation B Evaporation C Precipitation D Transpiration Your answer [1]
June 2023, Biology Paper 8 Higher, Q7 (1 mark): Lions hunt and eat antelopes. Which row correctly describes lions in this relationship? Type of factor Type of relationship A abiotic predator B abiotic prey C
June 2023, Biology Paper 8 Higher, Q13 (6 marks): 13* The pH of a soil will affect the crops that grow in the soil. When the soil pH is suitable, more crops will grow. This results in a higher yield (mass of cr
June 2023, Biology Paper 8 Higher, Q15(a) (1 mark): What word describes the interdependence between the hummingbird and the flower? [1]
June 2022, Biology Paper 1 Foundation, Q13(a) (1 mark): Plants are important for life on Earth as they photosynthesise and provide oxygen. Describe one other reason why plants are important to life on Earth. [1]
June 2022, Biology Paper 2 Foundation, Q2 (1 mark): Which abiotic factor affects the growth of plants? A Food B Nitrogen gas C Predators D Soil pH Your answer [1]
June 2022, Biology Paper 2 Foundation, Q3 (1 mark): Plasmodium is a microbe that causes the disease malaria in humans. Humans act as a host for plasmodium. Which term describes the relationship between plasmodium
June 2022, Biology Paper 2 Foundation, Q11(a) (2 marks): The diagram shows some of the levels of organisation within the ecosystem. Complete the diagram using words in the list. biomass community population predator p
June 2022, Biology Paper 2 Foundation, Q11(b) (2 marks): Explain why the carbon cycle is important to plants. [2]
June 2022, Biology Paper 2 Foundation, Q11(c) (3 marks): Microorganisms have an important role in the carbon cycle. Complete these sentences about microorganisms. Microorganisms break down dead organisms releasing nut
June 2022, Biology Paper 2 Foundation, Q16(b)(iii) (2 marks): Daisy plants require lots of light. Explain the effect of the shed on the growth of daisies in the lawn. [2]
June 2022, Biology Paper 8 Higher, Q3 (1 mark): Which term describes all the different organisms living in an environment? A Community B Ecosystem C Population D Species Your answer [1]
June 2022, Biology Paper 8 Higher, Q11(b)(iii) (2 marks): Daisy plants require lots of light. Explain the effect of the shed on the growth of daisies in the lawn. [2]
June 2022, Biology Paper 8 Higher, Q12(a) (3 marks): Complete these sentences about different factors that affect the ecosystem. Use the words or phrases in the list. abiotic biotic carbon dioxide food oxygen pH i
June 2022, Biology Paper 8 Higher, Q12(c) (3 marks): The bacteria live inside the bean plant cells in root nodules. The bacteria are able to take nitrogen gas from the air and turn it into nitrates. The plants use
November 2021, Biology Paper 2 Foundation, Q1 (1 mark): Which term describes all the different plants and animals that live in the same place? A Community B Ecosystem C Habitat D Trophic level Your answer [1]
November 2021, Biology Paper 2 Foundation, Q2 (1 mark): Cheetah hunt and kill zebra, then feed on the zebra meat. Which term describes this feeding relationship? A Competition B Mutualism C Parasitism D Predation You
November 2021, Biology Paper 2 Foundation, Q11(a) (3 marks): Materials are cycled in the environment. Complete these sentences about cycled materials. Choose words from this list. You can use each word once, more than onc
November 2021, Biology Paper 2 Foundation, Q11(b) (2 marks): Describe two ways that the water cycle is important to humans. 1 2 [2]
November 2021, Biology Paper 2 Foundation, Q11(c) (2 marks): Abiotic and biotic factors can affect ecosystems. Which two are biotic factors? Tick (✓) two boxes. Light intensity Food availability pH of soil Predators Tempe
November 2021, Biology Paper 2 Foundation, Q11(d)(i) (1 mark): The 24-hour rainfall for Sunday April 3 is ~1 mm. Explain what is meant by the term ~1 mm. [1]
November 2021, Biology Paper 8 Higher, Q3 (1 mark): Which term describes the interaction between living organisms and their physical environment? A Community B Ecosystem C Habitat D Trophic level Your answer [1]
November 2021, Biology Paper 8 Higher, Q8 (1 mark): Mutualism and parasitism involve two different organisms living together. Which statement describes the difference between mutualism and parasitism? A Both orga
November 2021, Biology Paper 8 Higher, Q12(a) (2 marks): Materials cycle through the environment. Complete these sentences about recycled materials. Carbon inside carbohydrates is released back into the atmosphere by
November 2021, Biology Paper 8 Higher, Q12(b)(i) (1 mark): Identify which of the bacteria in Fig. 12.1, if present in large amounts, would make the soil poor for plant growth. Tick (✓) one box. Decomposing bacteria Deni
November 2021, Biology Paper 8 Higher, Q12(b)(ii) (1 mark): Explain why large amounts of these bacteria would make the soil poor for plant growth. [1]
November 2021, Biology Paper 8 Higher, Q12(b)(iii) (1 mark): Abiotic and biotic factors can affect the bacterial communities. Which is a biotic factor? Tick (✓) one box. Ammonia + ammonium compounds Atmospheric nitrogen (
November 2020, Biology Paper 2 Foundation, Q2 (1 mark): Why are bacteria needed to recycle nitrogen in an ecosystem? A Bacteria are microscopic B Bacteria decompose organic material C Bacteria reproduce rapidly D Bac
November 2020, Biology Paper 2 Foundation, Q5 (1 mark): Which of these will increase the amount of water in the soil? A Evaporation B Precipitation C Translocation D Transpiration Your answer [1]
November 2020, Biology Paper 2 Foundation, Q12(d) (2 marks): Lichens are made up of algae and a fungus living together. Algae are single celled organisms that photosynthesise. The fungus produces a threadlike structure th
November 2020, Biology Paper 2 Foundation, Q14(a) (3 marks): Describe the levels of organisation in the savannah. Complete the missing parts of the table. Part of savannah Level Description giraffes elephants zebras trees
November 2020, Biology Paper 2 Foundation, Q14(b) (3 marks): Elephants have evolved large, very thin ears. This adaptation helps them to survive the effects of one abiotic factor affecting their population. Complete the s
November 2020, Biology Paper 7 Higher, Q16(b) (2 marks): Fig. 16.2 shows algae growing on the surface of a lake. Fig. 16.2 In the summer the area covered by the algae increases. Other plants growing at the bottom of t
November 2020, Biology Paper 8 Higher, Q3 (1 mark): Which of these is a biotic factor that can affect an ecosystem? A Acidity of soil B Bacterial levels in a river C Carbon dioxide levels in the atmosphere D Oxyg
November 2020, Biology Paper 8 Higher, Q4 (1 mark): Lichens are made up of a fungus and algae living together. The fungus gets nutrients from the algae and algae is sheltered by the fungus. Which term describes t
November 2020, Biology Paper 8 Higher, Q6 (1 mark): Carbon is recycled in the ecosystem. Which process helps reduce the level of carbon in the atmosphere? A Photosynthesis B Respiration C Translocation D Transpir
November 2020, Biology Paper 8 Higher, Q13(b) (3 marks): Table 13.2 shows the dry mass of algae on day 25 for all the temperatures measured in the experiment. Temperature (°C) Dry mass (g / litre) 10 0.12 20 0.25 25 0
June 2019, Biology Paper 2 Foundation, Q15(a) (1 mark): Water is cycled in nature. Name one abiotic factor that affects water uptake by a plant. [1]
June 2019, Biology Paper 2 Foundation, Q15(b)(i) (1 mark): Which process is shown by arrow X in the diagram above? Tick (3) one box. Combustion Decomposition Photosynthesis Respiration [1]
June 2019, Biology Paper 2 Foundation, Q15(b)(ii) (1 mark): Which process releases carbon when organisms die? Tick (3) one box. Combustion Decomposition Photosynthesis Transpiration [1]
June 2019, Biology Paper 8 Higher, Q6 (1 mark): Look at the diagram of part of the nitrogen cycle. Nitrogen in atmosphere Herbivore X Amino acids in organic matter Bean plant with root nodules Nitrates What i
June 2019, Biology Paper 8 Higher, Q8 (1 mark): Look at the effects of mercury waste from a factory. Fishermen eat large fish. Seawater normally contains 0.1 ppb (parts per billion) of mercury. Chemical waste
June 2019, Biology Paper 8 Higher, Q11(a) (1 mark): Water is cycled in nature. Name one abiotic factor that affects water uptake by a plant. [1]
June 2019, Biology Paper 8 Higher, Q11(b)(i) (1 mark): Which process is shown by arrow X in the diagram? Tick (3) one box. Combustion Decomposition Photosynthesis Respiration [1]
June 2019, Biology Paper 8 Higher, Q11(b)(ii) (1 mark): Which process releases carbon when organisms die? Tick (3) one box. Combustion Decomposition Photosynthesis Transpiration [1]
June 2019, Biology Paper 8 Higher, Q14(a) (1 mark): Plant material decomposes to make compost. Gardeners add compost to their soil to increase crop yield. Give one reason why compost increases crop yield. [1]
June 2018, Biology Paper 2 Foundation, Q1 (1 mark): Look at the diagram of the carbon cycle. Carbon dioxide in atmosphere X Gradual production of fossil fuels Coal, oil and gas Which process is shown by the arrow
June 2018, Biology Paper 2 Foundation, Q11(a)(i) (1 mark): Arrows labelled A represent the process of . [1]
June 2018, Biology Paper 2 Foundation, Q11(a)(ii) (1 mark): Arrows labelled B represent the process of . [1]
June 2018, Biology Paper 2 Foundation, Q11(a)(iii) (1 mark): Arrows labelled C represent the process of . [1]
June 2018, Biology Paper 2 Foundation, Q11(b)(i) (1 mark): How many predators does the shrimp have in this food web? [1]
June 2018, Biology Paper 2 Foundation, Q11(b)(ii) (2 marks): When plant material is decomposed by fungi, there is an increase in temperature. Complete the sentences to explain why. Choose words from the list. endothermic
June 2018, Biology Paper 2 Foundation, Q11(c)(i) (2 marks): Dogfish have two different interactions with the minnows. Write down the names of these two types of interactions. Describe when each interaction takes place. I
June 2018, Biology Paper 2 Foundation, Q11(c)(ii) (2 marks): One of the interactions benefits both minnows and dogfish. Explain how. [2]
June 2018, Biology Paper 8 Higher, Q2 (1 mark): Look at the diagram showing parts of the nitrogen cycle. Nitrogen in the air A B Herbivore C Dead organic matter Bean plant D with root nodules Nitrates Which p

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