RP10

• Core Practical 10


  • Carry out a study on the ecology of a habitat, such as using quadrats and transects to determine distribution and abundance of organisms, and measuring abiotic factors appropriate to the habitat
• Abiotic factors


  Non-living factors that influence the distribution of a species, e.g. light intensity, amount of water and nutrients, temperature
• Biotic factors


  Living factors that influence the distribution of a species, e.g. competition for resources, number of predators, disease
• Equipment


  • Quadrat
  • Transect (20m rope marked at 1m intervals)
  • Clipboard
  • Appropriate equipment to measure variable
• Method


  1. Choose a site where there is an obvious gradient in an abiotic variable, place the transect down, select a species that changes in abundance along the gradient

  2. Place the quadrat at each of the marks on the transect, placing the bottom left corner on the mark every time

  3. Record the percentage cover for the chosen species

  4. At each coordinate, measure 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
• Graph/Data Analysis


  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