7 (a) Fig. 7.1 shows part of a food web from a lake. perch duck freshwater snail pondweed algae pike stickleback water flea caddis fly larva water beetle Fig. 7.1 (i) Identify one tertiary consumer shown in the food web in Fig. 7.1. … [1] (ii) Identify one herbivore shown in the food web in Fig. 7.1. … [1] (iii) The food web is not complete. Ducks eat freshwater snails and pondweed. Draw two arrows on Fig. 7.1 to complete the food web to include this information. [1] (b) Pondweed can be used to investigate photosynthesis. Fig. 7.2 shows how the gas made by the process of photosynthesis can be collected. gas test-tube water pondweed light funnel beaker Fig. 7.2 (i) State the name of the gas that collects in the test-tube. … [1] (ii) When the light is switched off the experiment in Fig. 7.2 is in the dark and the amount of gas being produced by the pondweed changes. Suggest the change in the amount of gas being produced by the pondweed when the light is switched off. Give a reason for your answer. change in the amount of gas … reason … … [2] (c) Water is needed for the process of photosynthesis. Name the vessels in the plant that transport water. … [1] (d) Glucose is made by the process of photosynthesis. Plants use another process to release energy from glucose. Name the process that releases energy from glucose. … [1] [Total: 8]

7(a)(i) perch / pike ; 1 7(a)(ii) freshwater snail / caddis fly larva / water flea ; 1 7(a)(iii) arrow from freshwater snail to duck AND arrow from pondweed to duck ; 1 7(b)(i) oxygen ; 1 7(b)(ii) less / no, gas produced ; (because) light is needed for photosynthesis ; 2 7(c) xylem ; 1 7(d) (aerobic) respiration ; 1 To earn marks, you must identify 'perch' or 'pike' as a tertiary consumer, and 'freshwater snail', 'caddis fly larva', or 'water flea' as a herbivore. You need to draw two arrows: one from freshwater snail to duck, and another from pondweed to duck. For photosynthesis, you must state 'oxygen' as the gas produced. When light is off, you need to state that 'less' or 'no' gas is produced, and explain that 'light is needed for photosynthesis'. For the plant tissue, you must name 'xylem'. Finally, you must identify 'respiration' (or aerobic respiration) as the process that releases energy from glucose.

7 (a) Fig. 7.1 shows a food web. barn owls mice berries and nuts worms and insects dead leaves grasses voles shrews Fig. 7.1 (i) State the principal source of energy for a food web. … [1] (ii) The owl is the top carnivore in this food web. Define the term carnivore. … … [1] (iii) Complete the sentence to explain why shrews are classed as secondary consumers in this food web. Shrews are secondary consumers because they eat … , which are … consumers. [2] (b) Grass roots take in mineral ions from the soil to make amino acids. (i) State the name of the mineral ions needed to make amino acids. … [1] (ii) Grasses take in water from the soil through the root hair cells. Describe how water moves into root hair cells. … … … … [2] [Total: 7]

7(a)(i) Sun ; 1 7(a)(ii) animal that gets its energy by eating only other animals ; 1 7(a)(iii) worm and insects ; primary ; 2 7(b)(i) nitrate (ions) ; 1 7(b)(ii) (water moves) through, partially permeable membranes / cell membranes ; by osmosis ; 2

7 (a) Fig. 7.1 contains information about some organisms. • giraffes eat trees • lions hunt and eat giraffes • when lions die, vultures feed on parts of their dead bodies • the parts of the lion not eaten then decompose Fig. 7.1 (i) Construct the food chain for the organisms in Fig. 7.1. … [2] (ii) Identify the secondary consumer from Fig. 7.1. … [1] (iii) Giraffes are herbivores. State what is meant by herbivore. … … [2] (iv) Decomposition of the lion’s body returns carbon to the atmosphere as part of the carbon cycle. State the part of the carbon cycle that removes carbon from the atmosphere. … [1] (b) Living organisms are made up of cells. Cells contain different structures. State the functions of the cell membrane and the cell wall. cell membrane … … cell wall … … [2] [Total: 8]

7(a)(i) tree(s) → giraffe(s) → lion(s) → vulture(s) all organisms correct ; correct arrows ; 2 7(a)(ii) lion ; 1 7(a)(iii) (an animal that) gets its energy ; by (only) eating plants ; 2 7(a)(iv) photosynthesis ; 1 7(b) (membrane) controls the movement of substances in and out of the cells ; provides support ; 2

7 (a) Fig. 7.1 contains information about some organisms. • giraffes eat trees • lions hunt and eat giraffes • when lions die, vultures feed on parts of their dead bodies • the parts of the lion not eaten then decompose Fig. 7.1 (i) Construct the food chain for the organisms in Fig. 7.1. … [2] (ii) Identify the secondary consumer from Fig. 7.1. … [1] (iii) Giraffes are herbivores. State what is meant by herbivore. … … [2] (iv) Decomposition of the lion’s body returns carbon to the atmosphere as part of the carbon cycle. State the part of the carbon cycle that removes carbon from the atmosphere. … [1] (b) Living organisms are made up of cells. Cells contain different structures. State the functions of the cell membrane and the cell wall. cell membrane … … cell wall … … [2] [Total: 8]

7(a)(i) tree(s) → giraffe(s) → lion(s) → vulture(s) all organisms correct ; correct arrows ; 2 7(a)(ii) lion ; 1 7(a)(iii) (an animal that) gets its energy ; by (only) eating plants ; 2 7(a)(iv) photosynthesis ; 1 7(b) (membrane) controls the movement of substances in and out of the cells ; provides support ; 2

Cambridge IGCSE Combined Science · 0653

IGCSE Combined Science (0653) Organisms and their environment past paper questions

Revise IGCSE Combined Science (0653) — Organisms and their environment with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

143 free questions from 2016–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Organisms and their environment in IGCSE Combined Science 0653 exams, 2020–2025

Across 2020–2025, Organisms and their environment accounted for 158 questions worth 606 marks in Cambridge IGCSE Combined Science (0653) papers.

By year
Year	Questions	Marks
2020	15	74
2021	32	79
2022	26	96
2023	27	128
2024	33	136
2025	25	93

Most-tested subtopics

B15.2 Food chains and food webs464 marks
B15.1 Energy flow142 marks
B15.3 Carbon cycle107 marks

Appears in

Paper 1 · 56 qs
Paper 2 · 45 qs
Paper 3 · 29 qs
Paper 4 · 28 qs

All most-tested Combined Science topics

2021 Feb/Mar · Paper 3 · Q7 · 8 marks
Marking scheme
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2021 May/Jun · Paper 3 · Q7 · 7 marks
Marking scheme
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2021 Oct/Nov · Paper 3 · Q7 · 8 marks
Marking scheme
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2021 Oct/Nov · Paper 3 · Q7 · 8 marks
Marking scheme
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2021 Feb/Mar · Paper 1 · Q12 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q12
Answer: C
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