Adaptations (AQA GCSE Biology): Revision Note

Adaptations to the environment

• Adaptations are:

features that enable organisms to survive in the conditions in which they normally live

• These adaptations may be structural, behavioural or functional:

  • Structural: a physical part or feature of an organism, e.g.:

    • the white fur of a polar bear provides camouflage in the snow so it has less chance of being detected by prey

    • seals have a thick layer of fat (blubber) to insulate them against cold conditions

    • Arctic foxes have small ears to reduce surface area : volume ratio; this minimises heat loss in a cold environment

    • desert foxes have large ears to increase surface area : volume ratio; this increases heat loss in a hot environment

  • Behavioural: the way an organism behaves, e.g.:

    • reptiles bask in the sun to absorb heat

    • rabbits dig burrows in which to avoid predators while they sleep

    • some desert animals are only active in the early morning, late evening or at night, when it is cooler

  • Functional: biological processes within the organism, e.g.:

    • snakes produce venom to kill prey

    • mosquitos produce chemicals that stop an animal’s blood clotting when they bite, so that they can feed more easily

    • some desert animals have kidneys adapted to produce very concentrated urine, helping them retain water

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Extreme adaptations

• Some organisms live in environments that are extreme, such as:

  • very high or low temperatures,

  • very high or low pressures

  • high salt concentration

• Organisms that can live in extreme environments are called extremophiles

• Examples include:

  • bacteria living in deep sea volcanic vents where conditions are extremely hot, pressure is high and there is no sunlight

  • bacteria living in the dead sea, where salt concentrations are many times higher than normal sea water