Adaptations (AQA GCSE Combined Science: Trilogy: Biology): Revision Note

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

• Structural: a physical part or feature of an organism

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

  2. seals have a thick layer of fat (blubber) to insulate them against the cold conditions they live in

• Behavioural: the way an organism behaves

  1. cold-blooded reptiles bask in the sun to absorb heat

  2. rabbits dig burrows in which to live and raise offspring

• Functional: biological processes within the organism

  1. snakes produce venom to kill prey

  2. mosquitos produce chemicals that stop the animal’s blood clotting when they bite, so that they can feed more easily

Adaptations to 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

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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