GCSE AQA Biology 1 Adaptations, Competition & Environmental Change

GCSE AQA Biology 1 Adaptations, Competition & Environmental Change

1. Desert animal adaptations

   • Large surface area: volume ratio
     • Lose more body heat
   • Efficient with water
     • Lose less by producing...
       • ...small amounts of concentrated urine
       • ...little sweat
   • Good in hot conditions
     • Thin layers of body fat/coat to lose body heat (camels keep most fat in hump)
   • Camouflage
     • Sandy colour - can avoid predators/sneak up on prey

2. Arctic animal adaptations

   • Small surface area: volume ratio
     • Reduces heat loss
   • Well insulated
     • Thick layer of blubber (energy store)
     • Thick, hairy coats - keep body heat in
     • Greasy fur - sheds water which prevents cooling due to evaporation
   • Camouflage
     • White fur - can avoid predators/sneak up on prey

3. Desert plant adaptations

   • Small surface area: volume ratio
     • Plant lose water vapour from surface of leaves
       • Cacti have spines instead to reduce water loss
   • Water storage tissues
     • Cactus stores water in thick stem
   • Maximising water absoption
     • Cacti have shallow but extensive roots - absorb water quickly over large area
       • Others have deep roots - access underground water

4. Adaptations to deter predators

   • Armour
     • Roses - thorns
     • Cacti - sharp spines
     • Tortoises - shells
   • Poisons
     • Bees and poison ivy
   • Warning colours
     • Wasps

5. Extremophiles

   • Microorganisms - adapted to live in extreme conditions e.g. volcanoes, salty lakes, high pressure

6. Competition

   • Plants compete for: light, space, water and minerals (nutrients)
   • Animals compete for: space (territory), food, water and mates

7. Environmental change

   • Caused by...
     • Living factors
       • Change in occurence of diseases
       • Change in number of predators
       • Change in number of prey/availability of food source
       • Change in number/types of competitors
     • Non-living factors
       • Change in average temp.
       • Change in average rainfall
       • Change in level of air/water pollution
   • Affects population...
     • Population size increases
       • If number of prey increases, more food for predators - more predators survive & reproduce
     • Population size decreases
       • e.g. Number of bees in US falling rapidly. Could be because of pesticides, less food or more disease
     • Population distribution changes
       • Change in where an organism lives

8. Measuring environmental change

   • Living indicators
     • Some organisms very sensitive to changes in environment - indicator species
     • Lichen - very sensitive to levels of sulphur dioxide
       • Lots of lichen = clean air
     • Mayfly larvae - sensitive to concentration of dissolved oxygen in water
       • Mayfly larvae = clean water
     • Rat-tailed maggots & sludgeworms - adapted to live in polluted conditions
       • Rat-tailed maggots and sludgeworms = high level of water pollution
   • Non-living indicators
     • Satellites - measure temp. of sea surface & amount of snow/ice cover
     • Automatic weather stations - measure atmospheric temp.
     • Rain gauges - measure rainfall
     • Dissolved oxygen meters - measure amount in water (water pollution)