sampling organisms

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

  How to measure the population size of a common species and use sampling techniques.
• What is the purpose of random sampling in estimating population size?

  To obtain a representative estimate of the total population.
• What is the procedure for estimating the total population of daisies in a field?

  1. Use random sampling with a quadrat.
  2. Place two tape measures at right angles, each 20 meters long.
  3. Randomly select coordinates using a bag of numbers.
  4. Count daisies in the quadrat at those coordinates.
  5. Repeat for a total of ten samples.
  6. Use the formula to estimate total population.
• What are the dimensions of the quadrat used in the practical?

  0.5 meters by 0.5 meters.
• How do you calculate the total area of the field in the practical?

  The total area is calculated as \(20 \text{ m} \times 20 \text{ m} = 400 \text{ m}^2\).
• If the area sampled is \(2.5 \text{ m}^2\) and 300 daisies were counted, what is the estimated total population size?

  The estimated total population size is \(48,000\) daisies.
• Why is the population estimate considered an estimate?

  Because the sampled quadrats may not represent the entire area accurately.
• What factors should be considered when measuring the effect of light intensity on the distribution of daisies?

  • Light intensity
  • Distance from the tree
  • Water and mineral absorption by the tree
• What tool can be used to measure light intensity?

  A light meter or an app.
• How do you set up a transect line to measure the distribution of daisies?

  Place a tape measure from the tree and use a quadrat to count daisies at intervals.
• What might happen to the number of daisies as you move further from the tree?

  The number of daisies may increase due to higher light intensity.
• What is the relationship between light intensity and photosynthesis in plants?

  Plants need light for photosynthesis, so lower light intensity can reduce growth.
• What other abiotic factors might affect the number of daisies besides light intensity?

  Water and mineral availability in the soil.
• What is the importance of increasing the number of quadrat throws in sampling?

  • To cover a greater percentage of the area
  • To improve the accuracy of the population estimate
  • To account for variability in species distribution