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IB Biology SL C4.2 Transfers of Energy and Matter Questions

Practise IB Biology SL C4.2 by tracing energy flow, nutrient cycling, biomass transfer and ecological data across trophic levels.

Syllabus
First assessment 2025
Course
Biology SL
Level
SL

Exam points

  • distinguish continuous one-way energy flow from recycling and exchange of matter
  • trace light or chemical energy into producers and through consumers, detritivores and decomposers
  • calculate or interpret trophic transfer, productivity, biomass and losses from ecological data
  • trace carbon stores and fluxes and explain how photosynthesis, respiration or combustion alters sinks and sources

Covered syllabus points

C4.2.1—Ecosystems as open systemsC4.2.2—Sunlight as principal energy sourceC4.2.3—Chemical energy flowC4.2.4—Food chains and food websC4.2.5—Supply to decomposersC4.2.6—Autotrophs as self-feedersC4.2.7—Energy sourcesC4.2.8—HeterotrophsC4.2.9—Energy releaseC4.2.10—Trophic levelsC4.2.11—Energy pyramidsC4.2.12—Energy reductionsC4.2.13—Heat lossC4.2.14—Restrictions on trophic levelsC4.2.15—Primary productionC4.2.16—Secondary productionC4.2.17—Carbon cycle diagramsC4.2.18—Carbon sinks and sourcesC4.2.19—CO₂ release during combustionC4.2.20—Keeling Curve analysisC4.2.21—Dependence between respiration and photosynthesisC4.2.22—Recycling of all chemical elements

Learn this topic

Study C4.2 Transfers of energy and matter conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

Question 1

[Maximum number: 6]

Describe the movement of energy and nutrients in an ecosystem.

Question 2

[Maximum number: 7]

Compounds of carbon, hydrogen and oxygen are used to supply and store energy.

Explain how the energy supply in an ecosystem is dependent on sunlight.

Question 3

[Maximum number: 4]

The mass of an individual organism can affect its physiology and feeding ecology. The diagram shows the relative mass of carbon (black) and total wet mass (grey) of a marine crustacean, Calanus hyperboreus and a jellyfish, Bathocyroe fosteri.

Figure for Question 3 — IB Biology SL

Question (a)

(a)

State one process that results in the loss of carbon dioxide from a marine organism such as a crustacean or a jellyfish.

[ 1 ]

Question (b)

(b)

Explain how energy enters, flows through and is lost from marine food chains.

Figure for Question (b) — IB Biology SL
[ 3 ]
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