OCR - A-Level - Biology - Sampling Techniques

OCR - A-Level - Biology - Sampling Techniques

1. Animals

   • Sampling via Observation
     • Footprints
       • Tells timing of passage
     • Faeces
       • Tells food and timing
     • Bark rubbing
       • Territorial
       • Scratching, biting, scent, etc.
     • Leftover food
       • Saliva, appetite, teeth/claw marks
     • DNA Sequencing
       • Expensive but accurate
   • Methods of Sampling
     • Sweep nets
       • Ponds
         • Poke the mud then sweep backwards
         • Figure of 8 sweeping
       • Meadows
         • Figure of 8 sweeping
     • Pooters
       • Suck in one side, bring insects in
     • Pitfall Trap
       • Smaller organisms fall in, cannot get out
     • Tullgren Funnel
       • Light trap attracts insects, which fall in and cannot get out

2. Plants

   • Random sampling
     • Look to see which species are present
       • AVOID BIAS
     • Methods
       • Take samples at regular distances (random transect line)
       • Randomly generate numbers to correspond to coordinates in a region
       • GPS with random generation for deciding locations
   • Transect line
     • Decide on a line and take quadrat samples along this line
     • Biased if decided where to place the line
     • Random if the line was generated (or the like)
     • Gives a full range of samples
   • Number of samples should correspond to the size of the habitat
   • Tree sampling is easier because they can be seen clearly

3. Done to determine the biodiversity of an area

   • Biodiversity is the measure of the range of different species that live in a habitat

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