Practise 32 exam-style questions on Trophic levels (biology only) for AQA GCSE Biology. Write your answer as you would in the exam and get it marked in seconds against the mark scheme, point by point, with an AI tutor on hand if you get stuck.
32 questions
1–5 marks each
Instant marking
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20 questions, marked as you go
Sample questions with model answers
Here are 4 of the questions in this topic, each with a model answer, an explanation of why it earns the marks and the mark scheme an examiner would use.
Question 1
2 marks
State two ways energy is lost between trophic levels.
Model answer
Respiration (heat), undigested material / egestion, movement, waste products.
Explanation
Energy is used for metabolic processes and lost as heat, and some food cannot be digested so energy in it is not transferred to the consumer.
Mark scheme
1 mark
respiration / heat loss
1 mark
undigested material / faeces / egestion / waste
Either two of these or other valid loss mechanisms (movement) accepted.
Question 2
3 marks
Describe the shape and meaning of a pyramid of biomass.
Model answer
A pyramid of biomass is a pyramid-shaped diagram (wide base narrowing toward the top) where each bar shows the total mass of living tissue at each trophic level; the base is producers with the most biomass and higher trophic levels have less biomass.
Explanation
A pyramid of biomass shows the amount of organic matter at each trophic level — producers have the most mass, and much less mass is available at higher levels due to energy loss.
Mark scheme
1 mark
pyramid-shaped with bars that typically decrease in size from bottom to top
1 mark
each bar shows total mass (biomass) of organisms at that trophic level
1 mark
producers form the base (most biomass); biomass decreases at higher levels
Question 3
3 marks
A consumer feeds on primary consumers and producers. What term best describes its feeding behaviour and which trophic levels would it occupy?
Model answer
Omnivore; it feeds at multiple trophic levels so can be a primary consumer (when eating producers) and a secondary consumer (when eating primary consumers).
Explanation
Omnivores eat both plants and animals, so they may function at multiple points in food chains and food webs.
Mark scheme
1 mark
omnivore
1 mark
feeds at more than one trophic level
1 mark
occupies primary and secondary consumer positions depending on diet
Question 4
4 marks
A student claims that feeding more corn to cattle will increase the biomass at the carnivore trophic level (humans). Critically evaluate this statement.
Model answer
Feeding more corn to cattle (producers) may increase cattle biomass (primary consumer), but much energy is lost at each transfer so increase at human (carnivore) level will be small; efficiency is low and environmental impacts (land use, emissions) may make it unsustainable. Also humans are omnivores and food preferences matter.
Explanation
Though more plant feed increases livestock production, most energy is lost up trophic levels, so converting plant energy to human-edible meat is inefficient and has environmental costs.
Mark scheme
1 mark
increasing food for cattle may increase cattle biomass
1 mark
but energy loss between trophic levels means much is lost so small increase reaches humans
Reference to ~10% efficiency gains creditworthy.
1 mark
there are environmental / ethical problems (land use, greenhouse gases) so not a simple solution
1 mark
humans are omnivores and actual gain depends on diet, economics and sustainability
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