D4.2 Stability and change
Stability and change in ecosystems depend on sustainable resource use, pollution impacts, keystone species, rewilding, and succession processes over time.
- Syllabus
- First assessment 2025
- Topic
- D4.2
- Level
- —
What you’ll learn
15 learning objectivesChoose one objective for a focused lesson, or study the complete topic.
Exam analysis
An aggregate view of how the complete D4.2 Stability and change appears across past papers.
Chance of appearing24%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper3
Most tested objectives
- D4.2.9—Biomagnification26 questions
- D4.2.13 (HL)—Changes during primary succession20 questions
- D4.2.5—Keystone species16 questions
Common question formats
- Comparison
- Data analysis
- Definition or recall
- Evaluation
- Extended response
- Process explanation
- Structured response
Exam question appearances
November 2025Paper2 ["HL"] · TZ37(b)(i)[ 2 ]D4.2.5—Keystone species
November 2025Paper1A ["HL"] · TZ340[ 1 ]D4.2.8—Eutrophication
November 2025Paper1A ["HL"] · TZ139[ 1 ]D4.2.13 (HL)—Changes during primary succession
May 2025Paper2 ["SL"] · TZ24(c)[ 2 ]D4.2.11—Rewilding
May 2025Paper2 ["SL"] · TZ24(b)[ 2 ]D4.2.5—Keystone species
Practice this topic
5 original exam-style questions based on the patterns above.
Coverage 2010–2025 · Updated 16 Jul 2026