RP 12

• What are three abiotic factors that can affect an ecosystem?

  Light intensity, humidity, and temperature
• Name three biotic factors that influence an ecosystem.

  Competition for resources, predation, and disease
• How is percentage cover calculated in ecological studies?

  By counting the number of quadrat squares where the species is present, only if more than half of the square is covered
• What is the procedure for calculating percentage cover using a quadrat?

  1. Choose an area to sample and generate random coordinates.
  2. Use tape measures to create axes for coordinates.
  3. Place the quadrat at each coordinate, aligning the bottom left corner.
  4. Record the percentage cover for the chosen species.
  5. Measure the independent variable at each coordinate (e.g., light intensity).
• How can results from percentage cover studies be used to determine relationships between factors?

  By using statistical tests such as Pearson’s linear correlation or Spearman’s rank
• Why is a random number generator used in sampling?

  To avoid bias in random sampling
• What is the formula for the mark-release-recapture method?

  Population size = \(\frac{\text{no. in 1st sample} \times \text{no. in 2nd sample}}{\text{no. marked in 2nd sample}}\)
• What are the assumptions made when using the mark-release-recapture method?

  No births, deaths, or immigrations; random mixing of marked individuals; marking does not affect behavior or vulnerability
• What are the key assumptions when using the mark-release-recapture method?

  • No births, deaths, or immigrations occur during the study.
  • Marked individuals mix randomly with the population.
  • Marking does not affect the behavior of individuals or increase their vulnerability to predators.