Pearson Edexcel International GCSE in Biology · 4BI1 · Free · no account needed
Food Chains, Webs and Pyramids — exam questions
10 original Incandio exam-style questions on Food Chains, Webs and Pyramids, 22 marks, about 22 minutes of writing. Each one carries the command word, the tariff and the specification statement it assesses, exactly as a paper presents them. This is an original Incandio practice question, written to reflect the structure and demands of the qualification. It is not an official Pearson Edexcel past-paper question.
This is the practice set for Food Chains, Webs and Pyramids — the lesson that teaches it. Read the lesson first if the idea is new; come here when you want to find out whether you can turn it into marks. Completely free, no account needed to read.
What these questions ask of you
6 command words run through this set, and on Pearson Edexcel International GCSE Biology each one means something precise. Answering the wrong command is the commonest way a candidate who understands the lesson still loses the mark.
- Which (1 mark)
- one option chosen from the set given
- State (1 mark)
- one precise fact, no justification
- Give (1–2 marks)
- a short factual answer drawn from recall or from the data
- Explain (2–4 marks)
- a causal chain — WHY it happens, each link a separate marking point Misread as: describing what happens without giving the reason it happens
- Suggest (1–3 marks)
- a plausible answer applying taught biology to a situation not taught
- Calculate (1–3 marks)
- a numerical answer, with working where the tariff implies steps
Assessed on Paper 1 (4BI1/1B) and Paper 2 (4BI1/2B), against AO1, AO2, AO3.
Where these sit in the specification
Pearson Edexcel International GCSE Biology (4BI1) — statements 4.6 · 4.7. Incandio is aligned to this specification; it is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording.
The 10 questions
Answer them on paper, then open the lesson's exam practice to have them marked. The mark scheme, the accepted and rejected answers and the annotated model answer are in Incandio and are not printed here — an answer beside its question is not practice.
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Table 1 — the organisms in one food chain in an oak wood, with their numbers and their total dry mass in a measured area. Organism Trophic level Number Total dry mass / kg Oak tree producer 1 2400 Caterpillars primary consumer 48 000 96 Blue tits secondary consumer 160 3.2 Sparrowhawk tertiary consumer 1 0.3 (a)
(1)Give
Give the trophic level of the blue tits in Table 1.
Table 1 — the organisms in one food chain in an oak wood, with their numbers and their total dry mass in a measured area. Organism Trophic level Number Total dry mass / kg Oak tree producer 1 2400 Caterpillars primary consumer 48 000 96 Blue tits secondary consumer 160 3.2 Sparrowhawk tertiary consumer 1 0.3 (b)
(3)Explain
Explain why a pyramid of numbers drawn from Table 1 would have a very different shape from a pyramid of biomass.
Table 1 — the organisms in one food chain in an oak wood, with their numbers and their total dry mass in a measured area. Organism Trophic level Number Total dry mass / kg Oak tree producer 1 2400 Caterpillars primary consumer 48 000 96 Blue tits secondary consumer 160 3.2 Sparrowhawk tertiary consumer 1 0.3 (c)
(2)Calculate
Calculate the percentage of the caterpillars' dry mass that ends up as blue tit dry mass. Give your answer to 3 significant figures.
Table 1 — the organisms in one food chain in an oak wood, with their numbers and their total dry mass in a measured area. Organism Trophic level Number Total dry mass / kg Oak tree producer 1 2400 Caterpillars primary consumer 48 000 96 Blue tits secondary consumer 160 3.2 Sparrowhawk tertiary consumer 1 0.3 ............................ %
(Total for Question 1 = 6 marks)
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(1)Which
Which trophic level does a fox occupy in the chain grass → rabbit → fox?
Level A producer B primary consumer C secondary consumer D decomposer (Total for Question 2 = 1 mark)
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(1)State
State what the arrows in a food chain represent.
Figure 1 — a food chain and the pyramid of biomass built from it. (Total for Question 3 = 1 mark)
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(2)Give
Give the role of decomposers in an ecosystem.
(Total for Question 4 = 2 marks)
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(3)Explain
Explain why a pyramid of numbers for an oak wood is not pyramid-shaped, while a pyramid of biomass for the same wood is.
Figure 1 — a food chain and the pyramid of biomass built from it. (Total for Question 5 = 3 marks)
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(3)Explain
In a food web, the number of one predator falls sharply. Explain why this may change the numbers of species it does not eat.
(Total for Question 6 = 3 marks)
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(2)Suggest
Suggest why biomass in a pyramid is measured as dry mass rather than as the mass of the living organisms.
(Total for Question 7 = 2 marks)
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(4)Explain
Explain why a pyramid of numbers can be an odd shape while a pyramid of biomass for the same food chain is almost always a true pyramid.
(Total for Question 8 = 4 marks)
Have them marked, then defend the answer
Practice tells you the mark; teaching it back tells you whether you understand it. On Incandio a topic counts as mastered only once you have taught it and defended it.
- Mark these questions — 10 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain Food Chains, Webs and Pyramids to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Aristotle over three rounds, marked against descriptors you can read first.
Completely free. No subscriptions, no paywalls, no account needed to start.
Back to the lesson
- Food Chains, Webs and Pyramids — Who eats whom, drawn three different ways — and why only one of the three can come out upside down.
- All of Incandio Biology · Incandio Exam Practice