Edexcel IGCSE Biology 2.83 plant responses to stimuli
Practise explaining plant responses to stimuli, especially how environmental cues such as daylight can affect growth or flowering.
- Syllabus
- First assessment 2019
- Course
- Biology 4BI1
Exam points
- explain why daylight length may be a more reliable seasonal cue than temperature
- apply plant stimulus-response ideas to flowering, growth or other plant behaviour contexts
2.83 Plant responses to stimuli question 1
[Maximum number: 2]
The body has a hormonal control system that coordinates some of the body's responses.
Plants also respond to changes in their environment.
In many plants, flowering is stimulated by the number of hours of daylight.
Suggest why flowering in many plants is stimulated by the number of hours of daylight rather than by temperature.
An explanation makes reference to two of the following points:
1. hours of daylight (better) indicator of season / time of year /eq
2. daylight does not vary / temperature can vary (day to day) / eq
3. (more hours of) daylight allow insects to see flowers / eq
4. (more) insect pollination / insects pollinate in daylight / eq
eg more hours/
daylight in summer
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