Hydrophytes are plants adapted to live in very wet habitats. Describe four adaptive features of hydrophytes that increase their ability to survive and reproduce in such environments.

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)

Large, flat leaves maximise surface area for gas exchange and water loss.
Stomata are positioned on the upper leaf surface where light is greatest.
A high density of stomata, usually open, allows rapid water vapour diffusion.
Leaves have a thin or absent waxy cuticle, so water can pass freely.

Examiner tips

  • Use the exact wording from the mark scheme – e.g. "large, flat leaves". Show the link between each feature and survival in wet habitats. Keep each point brief and separate with a line break or number.

Common mistakes

  • Writing "stomata on the lower surface" – they are on the upper. Forgetting to mention the thin or absent cuticle. Using vague terms like "many stomata" without noting they are usually open.

Mark scheme (4 marks)

  1. Large, flat leaves to maximise surface area for water loss / gas exchange
  2. Stomata positioned on the upper surface of the leaf (where sunlight hits) to allow water vapour to diffuse out
  3. Large number of stomata (usually open) to allow water vapour to diffuse out freely
  4. Thin or no waxy cuticle so water loss is not restricted / water can pass freely

Key terms in this question

hydrophytes · adaptive feature

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