# Explain how the structural and behavioural adaptations of a named desert mammal help it to maintain water balance.

> IB DP Biology Standard Level (2023 syllabus) — B4.1 Adaptation to environment · Explain · 4 marks

> Desert mammals face extreme heat and scarce water, yet many species thrive in arid environments through a suite of integrated adaptations.

## Mark scheme (4 marks)

1. Named desert mammal stated (e.g. kangaroo rat, fennec fox, camel, jerboa)
2. Structural adaptation identified AND linked to reducing water loss or conserving water — e.g. highly efficient kidneys produce concentrated urine, reducing water lost in excretion; or nasal countercurrent cooling recovers water vapour from exhaled air
3. Behavioural adaptation identified AND linked to reducing water loss or conserving water — e.g. nocturnal/crepuscular activity avoids peak heat, reducing evaporative water loss through sweating and panting
4. Explanation of how the two adaptations work together / are complementary to maintain water balance, or a mechanistic explanation of why reduced activity reduces evaporative loss (e.g. lower body temperature means less sweating / panting, so less water lost through evaporation from skin and respiratory surfaces)

## Key terms

- [water balance](https://www.gradenine.co.uk/glossary/water-balance)
- [behavioural adaptation](https://www.gradenine.co.uk/glossary/behavioural-adaptation)

## Related

- [Revision notes for IB DP Biology Standard 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-the-structural-and-behavioural-6242e5c1) · Published by Druglandscape Ltd.