pratical 13

• A hypothesis of the effect of a change in an abiotic factor such as light intensity on the distribution of plant species can be written.
• A tape measure can be used to create an ecological gradient of shaded to unshaded area.
• A quadrat can be placed along the '0' end of the tape measure, with one corner touching the '0' mark.
• The number of plants can be counted and recorded in a table.
• The quadrat can be placed 5 m up the tape measure and the process repeated until the end of the transect line is reached.
• Data from the class can be gathered to find the mean number of plants at each point along the transect.
• A graph of 'number of plants' against the ecological gradient that is observed as the distance along the transect line increases can be plotted.
• The results can be compared to the hypothesis.
• quadrats

  1. Use a random number generator to obtain 2 numbers, which are to be used as coordinates to find a location on the 2 tape measures set up in one site.
  2. Set down the quadrat at the coordinates.
  3. Identify different plant species found in the quadrat. Count and record the number ofindividuals of each species in the quadrat.
  4. Repeat steps 1-3 to take 9 more samples.
  5. Estimate the population size of the different species using this formula:total area / area sampled x total number of individuals of each species counted