C4.2.4—Food chains and food webs
Food chains and food webs explains how energy flow, matter cycling or carbon transfer is represented, measured or limited within ecosystems.
- Syllabus
- First assessment 2025
- Objective
- C4.2.4
- Level
- SL
Exam analysis
Chance of appearing7%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper2
Typical marks1–4
Common command terms
- Describe
- Identify
- Label
- Draw
- Explain
- Compare
- Contrast
- Outline
- Evaluate
Scoring notes
- Common mistake
- Saying energy is recycled instead of flowing through and leaving ecosystems as heat.
Recent exam appearances
May 2025Paper2 ["SL"] · TZ27(b)[ 4 ]C4.2.4—Food chains and food webs
November 2021Paper2 ["SL"] · TZ03(b)(i)[ 1 ]C4.2.4—Food chains and food webs
November 2018Paper1 ["SL"] · TZ017[ 1 ]C4.2.4—Food chains and food webs
November 2017Paper3 ["SL"] · TZ013(b)[ 2 ]C4.2.4—Food chains and food webs
November 2016Paper2 ["SL"] · TZ01(e)[ 2 ]C4.2.4—Food chains and food webs
Practice this objective
Coverage 2010–2025 · Updated 16 Jul 2026
Concept essentials
- Food chains and food webs must be linked to the correct source, store, transfer or loss process.
- The evidence for food chains and food webs depends on distinguishing energy flow from matter cycling.
- Food chains and food webs is clearer when arrows, units and trophic positions match the biological process.
- Data or diagrams for food chains and food webs need interpretation as ecosystem transfer evidence.