year 9 sampling organisms + practical

• What technique do scientists use to determine species abundance and distribution?

  Sampling
• What are the two methods of sampling mentioned?

  Random sampling and transect sampling
• What is a quadrat?

  A wooden or plastic square
• How is a quadrat used in random sampling?

  It is placed on the ground to count organisms
• What hypothesis might scientists investigate using random sampling?

  Fewer ferns are found in light conditions
• Why is it important to place the quadrat multiple times?

  To ensure valid results and accurate representation
• What is the equation for estimating total population size?

  Total population size = (total area / area sampled) × organisms counted
• What is a transect?

  A line across a habitat for sampling
• How do scientists use a transect in their research?

  By counting organisms at intervals along it
• How do species numbers change across a sand dune?

  They change as you move inland from the sea
• What should be done to ensure valid results when sampling along a transect?

  Repeat the process multiple times
• What are the steps involved in random sampling using a quadrat?

  • Place the quadrat randomly on the ground
  • Count the number of organisms inside
  • Repeat at multiple random locations
  • Calculate the average for valid results
• What are the steps involved in sampling along a transect?

  • Place a tape measure across the habitat
  • Use a quadrat at set intervals along the transect
  • Count the organisms in each quadrat
  • Repeat the process multiple times for accuracy
• What factors can affect the number of organisms in a location?

  • Light intensity
  • Temperature
  • Levels of moisture
  • Variability of abiotic factors
• What is the significance of using random numbers in sampling?

  • Ensures unbiased selection of quadrat locations
  • Increases the reliability of the data collected
  • Helps in achieving a representative sample
• 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 two tape measures at right angles.
  3. Select random numbers to determine quadrat placement.
  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 quadrat's position during sampling?

  By drawing random numbers from a bag
• If students counted 300 daisies across ten quadrats, what is the next step?

  Estimate the total population using a formula
• What is the formula 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 square meters
• What is the area sampled if each quadrat is 0.25 square meters and there are 10 quadrats?

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

  Sampling may not represent the entire area
• What factor is being investigated in relation to the distribution of daisies?

  Light intensity
• How do you measure the effect of light intensity on 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 or app.
  4. Analyze how daisies change with distance from the tree.
• What happens to the number of daisies as you move away from the tree?

  It may increase due to higher light intensity
• What other abiotic factor might affect the number of daisies besides light intensity?

  Water and minerals absorption by the tree
• Where can students find additional questions on this practical?

  In the vision workbook linked in the video
• Why is it important to repeat the sampling process multiple times?

  To increase accuracy and reliability of results