Required Practical 9-sampling Organisms

• What should you be able to describe by the end of the video?

  Population size measurement and sampling techniques
• What is the purpose of random sampling in estimating population size?

  To obtain an unbiased estimate of species distribution
• What is the procedure for estimating the total population of daisies in a field?

  1. Use random sampling with quadrats.
  2. Place tape measures at right angles.
  3. Select random numbers to position quadrats.
  4. Count daisies in each quadrat.
  5. Use the formula to estimate total population.
• What is the size of the quadrat used in the practical?

  0.5 meters by 0.5 meters
• How do students select the position for the quadrat?

  By drawing random numbers from a bag
• How many samples should students take in total?

  Ten samples
• What is the equation used to estimate the total population size?

  Total population size = (total area / area sampled) * number counted
• What is the total area of the field if it measures 20 meters by 20 meters?

  $400 \text{ m}^2$
• What is the area sampled if each quadrat is 0.25 meters by 0.25 meters and ten quadrats are used?

  $2.5 \text{ m}^2$
• What is the estimated total population of daisies if 300 daisies are counted?

  48,000 daisies
• Why is the population estimate considered an estimate?

  Because it may not represent the entire area
• How do you measure the effect of light intensity on the distribution of daisies?

  1. Use a transect line from the tree.
  2. Count daisies at intervals along the line.
  3. Record light intensity using a light meter.
  4. Analyze how daisies change with distance from the tree.
• What tool can be used to measure light intensity?

  A light meter or an app
• Why might there be fewer daisies under a tree?

  Lower light intensity affects photosynthesis
• What other abiotic factor might affect the number of daisies besides light intensity?

  Water and minerals absorption by the tree
• What are the key components of the required practical for measuring species distribution?

  • Random sampling with quadrats
  • Estimating total population size
  • Measuring light intensity effects
  • Using transect lines for data collection