D4.3.9 (HL)—Phenology
Phenology studies the timing of recurring seasonal biological events such as budburst, migration, breeding, emergence, and disease-vector activity each year.
- Syllabus
- First assessment 2025
- Objective
- D4.3.9
- Level
- HL
Exam analysis
Chance of appearing2%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper2
Typical marks1–2
Common command terms
- Identify
- Analyse
Recent exam appearances
November 2025Paper1A ["HL"] · TZ339[ 1 ]D4.3.9 (HL)—Phenology
November 2019Paper2 ["HL"] · TZ01(d)[ 2 ]D4.3.9 (HL)—Phenology
November 2019Paper2 ["HL"] · TZ01(c)[ 1 ]D4.3.9 (HL)—Phenology
Practice this objective
Coverage 2019–2025 · Updated 16 Jul 2026
Concept essentials
- Phenology is the study of seasonal timing in biological events.
- Warming can shift when insects, plants, birds, or pathogens are active.
- Phenological data can identify changes in exposure, reproduction, migration, or resource availability.