Adaptation

In the syllabus and the exam

Adaptation is introduced in the chapter on how plants adapt to different habitats, where a candidate identifies a named plant as a xerophyte, hydrophyte or mesophyte from its structural features and explains how each feature solves a specific survival problem posed by that habitat's water supply, light or support conditions. In Paper 2, a full-credit answer names the feature, states the problem it overcomes, and explains the mechanism, for example 'a thick cuticle reduces water loss by evaporation through the epidermis', rather than the vague claim that a plant 'is suited to dry conditions'. Later chapters on ecosystems and biodiversity extend the same term to animals and microorganisms, covering structural adaptations (camouflage, body shape), physiological adaptations (enzyme tolerance to a narrow temperature range) and behavioural adaptations (nocturnal activity to avoid heat), so candidates should be ready to sort a described feature into the correct one of these three categories. A frequent error is describing what a feature looks like without linking it to the problem it solves, which earns no marks because the structure-function link is what is actually being tested. Adaptation is also often confused with acclimatisation: an adaptation is an inherited feature shaped over many generations by natural selection, while acclimatisation is a temporary, reversible change one organism makes within its own lifetime, such as producing more red blood cells after months at high altitude. Higher-order items sometimes describe an unfamiliar organism's habitat and ask candidates to predict a plausible adaptation, rewarding reasoning rather than memorised textbook examples.

Example

The thick waxy cuticle and sunken stomata of a cactus are adaptations that cut water loss in a desert habitat, while the air-filled aerenchyma inside a water lily's stem is an adaptation that keeps its floating leaves at the water surface.

Related terms

XerophyteHydrophyteSpecies

Source:SRC-DSKP-EN