# Explain how climate change may affect the timing of seasonal biological events, such as flowering and insect emergence, and how mismatches in these timings can affect ecosystem function.

> IB DP Biology Higher Level (2023 syllabus) — D4.3 Climate change · Explain · 4 marks

## Mark scheme (4 marks)

1. Rising temperatures cause earlier onset of spring conditions, which triggers earlier flowering / bud burst / insect emergence / migration in many species.
2. Different species respond to temperature change at different rates, so the timing of interdependent events (e.g. peak flower availability and pollinator activity) becomes uncoupled / mismatched.
3. A phenological mismatch reduces the overlap between resource availability and consumer demand, leading to reduced reproductive success / decreased food availability for dependent species (e.g. chicks hatching after peak caterpillar abundance).
4. Disruption of these ecological interactions (e.g. pollination, predator–prey cycles) can reduce ecosystem stability / biodiversity / ecosystem services such as crop pollination.

## Key terms

- [ecosystem function](https://www.gradenine.co.uk/glossary/ecosystem-function)

## Related

- [Revision notes for IB DP Biology Higher Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-climate-change-may-affect-9627ff73) · Published by Druglandscape Ltd.