Biology GCSE Part1B

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  • Created by: Katy Head
  • Created on: 19-05-11 19:24

ADAPTATION IN ANIMALS

Living organisms have special features, known as adaptations, to allow them to survive in their particular habitat.

Animals in cold climates 

  • you lose heat through your body surface - mainly your skin
  • The amount you lose is closely related to your surface area : volume (SA/V) ratio
  • The lower the ratio  the more body heat you can retain
  • Think of two cubes
    • one has sides of 1cm - each side is 1sq cm - so total surface area is 6 sq cm
    • Volume is 1* 1* 1 = 1 cubic centimetre
    • ratio is 6:1
    • Now do the same with a cube of sides of 3 cm - each side has a surface area of 9 sq cm - so total surface area for 6 sides = 54 sq cm
    • Volume = 3 * 3 * 3 = 27 cubic centimetres
    • ration is 54:27 = 2:1
    • The larger cube has a much lower ratio
  • This is why so many arctic animals are relatively large - polar bears, seals and walruses
  • The surface area of places where the skin is thinnest e.g. ears are very small
  • A thick layer of fat - blubber that builds up under the skin
  • A thick fur coat outside will insulate well
  • The fat layer also provides food supply - built up in summer when food is plentiful and used in winter when food is scarce
  • Camouflage - many animals, including the arctic fox, the arctic hare and the stoat change the colour of their coats to pure white in winter

Surviving in dry climates

  • Dry climates are often hot climates - like deserts
  • Deserts
    • scorching heat in the day and bitter cold at night
    • lack of water
    • need to stop body temperature rising too high
  • Many desert animals need little or no water - getting all they need from the food they eat
  • Desert animals are often active in early morning and late evening when the temperature is most comfortable
  • They rest in the heat of the day and in the night
  • They are found in burrows well below the surface where the temperature is more constant
  • Many desert animals are small - their SA/V is high
  • Large thin ears to help lose heat
  • not much fur
  • ralatively little body fat
  • the wrinkly skin on an elephant increases the surface area and the SA/V to aid heat loss

Key points:-

  • All living things have adaptations to help them survive the conditions where they live
  • Animals which are adapted for cold environments are often large, with a small surface area - volume ratio (SA/V). They have thick layers of fat and fur.
  • Changing coat colour in the differnt seasons gives animals all year round camoflauge
  • Adaptations for hot, dry environments include a large SA/V ratio, thin fur, little body fat and behaviour patterns that avoid the heat of the day.

ADAPTATION IN PLANTS

No plants can grow :-

  • in deep oceans where there is no light
  • in the icy wastes…

Comments

ISAIAHISGAY

Think of two cubes

  • one has sides of 1cm - each side is 1sq cm - so total surface area is 6 sq cm
  • Volume is 1* 1* 1 = 1 cubic centimetre
  • ratio is 6:1
  • Now do the same with a cube of sides of 3 cm - each side has a surface area of 9 sq cm - so total surface area for 6 sides = 54 sq cm
  • Volume = 3 * 3 * 3 = 27 cubic centimetres
  • ration is 54:27 = 2:1

I am very much so confused please explain if you would be so kind

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