practical 12

• Abiotic factors


  Non-living factors that determine the distribution of a species
• Abiotic factors


  • Light intensity
  • Amount of water and nutrients
  • Temperature
• Biotic factors


  Living factors that determine the distribution of a species
• Biotic factors


  • Competition for resources
  • Amount of predators
  • Disease
• Equipment


  • Quadrat
  • 2x tape measure
  • Appropriate equipment to measure variable
• Method


  1. Choose a 5x5m area

  2. Use a random number generator to generate 10 sets of random coordinates

  3. Use two tape measures to create a set of axes

  4. Place the quadrat at each of the coordinates, placing the bottom left corner on the coordinate

  5. Record the percentage cover for the chosen species
• Measuring the independent variable


  At each coordinate, take a measure of the independent variable (e.g. light intensity using a photometer)
• Hazards


  • Biohazard (allergies, soil bacteria, contamination)
  • Slippery surfaces
• Safety precautions


  • Wash hands after practical
  • Wear appropriate footwear, don't run
• Emergency response


  • Seek assistance
  • Seek appropriate medical attention
• Graphing and analysing data

  1. Plot a graph of the percentage cover against the chosen independent variable

  2. Carry out statistical tests including Spearman's Rank, T-test and Chi Squared
• Correlation is not necessarily causation - there could be a range of factors that influence the results