IB Biology HL D4.3.9 Hl Phenology Questions
Analyse how day length, temperature and lunar cycles regulate flowering, tick activity and reproductive events across seasons.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- Explain how photoperiod and phytochrome-related gene activation control flowering at a precise seasonal time in long-day or short-day plants.
- Analyse seasonal or lunar-linked timing data for ticks and reproductive events by comparing distributions, identifying peaks and sequences, and suggesting environmental controls.
- Identify a valid phenological research question by distinguishing the timing of recurring events such as tree budburst from non-seasonal population or evolutionary measures.
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IB Biology HL D4.3.9 Hl Phenology Questions question 1
The black-legged tick (lxodes scapularis) is an arthropod which sucks blood from humans and other mammals. It is encountered mainly in wooded and semi-wooded areas.
Some ticks can be infected by the bacterium Borrelia burgdorferi. When a tick bites a human, the bacterium is often introduced, causing Lyme disease. Lyme disease is a public health problem in North America and, if left untreated, can cause important neurological impairment. The diagram represents the two-year life cycle of a tick.
Using the life cycle diagram and the graph for the year 2000, analyse the distribution of adult ticks throughout the different seasons.
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