D4.2.4—Mesocosm model
Mesocosms model ecosystem stability by enclosing simplified communities where matter cycling, energy input, variables, and population changes can be observed.
- Syllabus
- First assessment 2025
- Objective
- D4.2.4
- Level
- HL
Exam analysis
Chance of appearing4%of analysed past papers
Latest appearanceMay 2024
Most common paperPaper3
Typical marks1–3
Common command terms
- Discuss
- Outline
- State
- Suggest
- Explain
Scoring notes
- Common mistake
- Assuming a sealed mesocosm exchanges no energy, when light or heat can still pass between the system and surroundings.
Recent exam appearances
May 2024Paper2 ["HL"] · TZ25(b)[ 2 ]D4.2.4—Mesocosm model
May 2023Paper3 ["HL"] · TZ23(b)[ 1 ]D4.2.4—Mesocosm model
November 2018Paper3 ["HL"] · TZ014(d)[ 2 ]D4.2.4—Mesocosm model
May 2017Paper3 ["HL"] · TZ13(b)[ 3 ]D4.2.4—Mesocosm model
Practice this objective
Coverage 2017–2024 · Updated 16 Jul 2026
Concept essentials
- A sealed mesocosm restricts matter exchange but can still exchange energy with its surroundings.
- Mesocosms support replication and variable control while preserving some ecological interactions.
- Model limitations arise because natural environments vary more than small enclosed systems.