AQA GCSE Biology

Revision Notes

7.1.4 Adaptations

Adaptations to the Environment

  • Organisms have features (adaptations) that enable them to survive in the conditions in which they normally live. These adaptations may be structural, behavioural or functional:

Types of adaptation to the environment table

Types of adaptation to the environment table, IGCSE & GCSE Biology revision notes

Adaptations to the cold regions

  • Animals here often have a small surface area : volume ratio to minimise heat loss to their surroundings (rounded shape of penguins/seals, small ears of the Arctic fox)
  • A thick layer of fat (seal blubber) or fur (polar bears) insulates against the cold
  • These are examples of structural adaptations

Adaptations to desert regions

  • Some desert animals have specially adapted kidneys which produce very concentrated urine, helping the animal to retain water – this is a functional adaptation
  • Some are only active in the early mornings, late evenings or at night when it is cooler – this is a behavioural adaptation
  • Some animals have structures to increase their surface area : volume ratio to aid heat loss (large ears of African elephants) – these are structural adaptations


Structural adaptations of a cactus, IGCSE & GCSE Biology revision notes

A cactus has many structural adaptations to help it survive in the desert

Extreme Adaptations

  • Some organisms live in environments that are very extreme, such as at very high or low temperatures, pressures, or high salt concentration
  • Organisms that can live in extreme environments are called extremophiles
  • An example of habitats where extremophiles are found are deep-sea volcanic vents, where the conditions are extremely hot, under high pressure and there is no sunlight
  • Bacteria called chemoautotrophs survive by using inorganic chemicals to obtain energy (rather than using sunlight in photosynthesis as photoautotrophs do)
  • Other species can then use the bacteria as a source of nutrition – the bacteria are producers in these food chains

Exam Tip

Make sure you understand the concept of surface area : volume ratios and why they are important when it comes to how animals are adapted to cold or hot environments, as this is a tricky concept that often comes up in exams.

A small surface area : volume ratio means that the animal has a small surface area compared to its volume. This helps to reduce heat loss. A large surface area : volume ratio means that the animal has a large surface area compared to its volume. This helps to increase heat loss.

Generally, the larger the animal, the smaller its surface area : volume ratio.

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Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.

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