Sampling organisms practical

• 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 a representative sample of species
• What size quadrat is used in the practical?

  0.5 meters by 0.5 meters
• How do you set up the tape measures for random sampling?

  Place them at right angles, 20 meters long
• What is the first step after placing the tape measures?

  Students draw numbers from a bag
• How many samples should students collect in total?

  Ten samples
• If students counted 300 daisies, what is the next step?

  Estimate the total population using an equation
• What is the equation to estimate total population size?

  Total population size = (total area / area sampled) * number counted
• What is the total area of the field in square meters?

  400 square meters
• What is the area sampled if each quadrat is 0.25 square meters?

  2.5 square meters
• Why is the population estimate considered an estimate?

  Sampling may not represent the entire area
• What should be done if the quadrat throws do not represent the area?

  Increase the number of quadrat throws
• What factor is being investigated in the second part of the practical?

  Light intensity's effect on daisies
• How do you measure the effect of light intensity?

  Use a transect line and light meter
• What should be recorded at the start of the transect?

  Number of daisies and light intensity
• What happens as you move further from the tree?

  Number of daisies may increase
• Why might light intensity not be the only factor affecting daisies?

  Trees absorb water and minerals from soil
• Where can students find more questions on this practical?

  In the vision workbook linked