Distribution and Abundance of Organisms

• What is the first step to estimate population size using quadrats?

  Place a 1 m² quadrat at random
• Why should you watch out for wild quadrats when counting daisies?

  To ensure accurate counting of daisies
• How do you calculate the mean number of daisies per quadrat?

  Mean = total number of organisms / number of quadrats
• If there are 154 daisies in 7 quadrats, what is the mean number of daisies per m²?

  22 daisies per m²
• How do you estimate the population size of daisies in a field?

  Multiply area by organisms per m²
• If a field has an area of 800 m² and the mean is 22 daisies per m², what is the population size estimate?

  17,600 daisies
• What is the first step to find how organisms are distributed across an area using transects?

  Mark out a line using a tape measure
• How do you count daisies using transects?

  Count in quadrats at regular intervals
• What should you do after counting daisies along the transect?

  Draw a graph to show distribution
• What are the steps to estimate population size using quadrats?

  1. Place a 1 m² quadrat at random.
  2. Count all the daisies within it.
  3. Repeat several times and calculate the mean.
  4. Multiply the area by the mean number of organisms per m².
• What are the steps to find how organisms are distributed using transects?

  1. Mark out a line using a tape measure.
  2. Count daisies in quadrats at regular intervals.
  3. Draw a graph to show distribution.
• What does the graph of abundance show in relation to distance from the pond?

  • Abundance of daisies decreases or increases with distance.
  • Specific values can be plotted against distance.