Xerophytes are plants adapted to live in dry habitats. Describe four adaptive features of xerophytes that reduce water loss.

Cambridge International IGCSE Biology (0610) — 18.2 Adaptive features · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

1. Fewer stomata or stomata that are sunken in pits reduce the water potential gradient, limiting transpiration.
2. Small, rolled leaves or spines reduce the leaf surface area, thereby decreasing water loss.
3. A thick waxy cuticle forms a waterproof barrier that prevents water from evaporating.
4. Deep or extensive root systems allow the plant to absorb water from deeper in the soil or store large amounts of water.

Examiner tips

  • Use the exact terms: stomata, cuticle, surface area, deep roots. Show the link between each feature and reduced water loss. Keep the answer concise – one sentence per feature.
  • Include the reason for each adaptation (e.g. lower water potential gradient, reduced surface area).

Common mistakes

  • Writing ‘more stomata’ instead of ‘fewer’. Using vague phrases like ‘good leaves’ instead of ‘small, rolled leaves or spines’.

Mark scheme (4 marks)

  1. Fewer stomata / stomata sunken in pits reduces water loss by lowering the water potential gradient
  2. Small, rolled leaves or spines reduce surface area, limiting water loss
  3. Thick waxy cuticle provides a waterproof barrier to prevent water loss
  4. Deep roots allow absorption of water from deep in the soil / roots store large amounts of water

Key terms in this question

xerophyte · adaptive feature

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