C4.2.8—Heterotrophs
Heterotrophs obtain organic carbon compounds from other organisms or detritus, using digestion and respiration to build biomass and release usable energy.
- Syllabus
- First assessment 2025
- Objective
- C4.2.8
- Level
- SL
Exam analysis
Chance of appearing6%of analysed past papers
Latest appearanceMay 2023
Most common paperPaper1
Typical marks1
Common command terms
- Identify
- Describe
- State
- Compare
- Contrast
Scoring notes
- Common mistake
- Reversing food-web arrows instead of showing energy transfer direction.
Recent exam appearances
May 2023Paper2 ["SL"] · TZ24(a)(i)[ 1 ]C4.2.8—Heterotrophs
May 2023Paper1 ["SL"] · TZ218[ 1 ]C4.2.8—Heterotrophs
November 2022Paper1 ["SL"] · TZ017[ 1 ]C4.2.8—Heterotrophs
May 2018Paper1 ["SL"] · TZ217[ 1 ]C4.2.8—Heterotrophs
November 2015Paper1 ["SL"] · TZ018[ 1 ]C4.2.8—Heterotrophs
Practice this objective
Coverage 2011–2023 · Updated 16 Jul 2026
Concept essentials
- Heterotrophs must be linked to the correct source, store, transfer or loss process.
- The evidence for heterotrophs depends on distinguishing energy flow from matter cycling.
- Heterotrophs is clearer when arrows, units and trophic positions match the biological process.
- Data or diagrams for heterotrophs need interpretation as ecosystem transfer evidence.