REQUIRED PRACTICAL sampling organisms

Question 1

method for randomly sampling organisms

Answer 1

• place 2 20m tape measures at right angles
• use a random number generator (to generate numbers from 1 to 20)
• walk the number of distance in meters that you get across
• another walk the number of distance in meters that you got up
• place a quadrat where the 2 people will meet
• record the number of daisies in the quadrat
• repeat the process 9 more times (so you have 10 samples)
• work out the mean number of plants per quadrat
• find the total survey area
• do the total surface area/ area of quadrat to figure out the number of quadrats in the survey area
• figure out the number of daises (number of quadrats in survey area x number of plants)
• number of daisies = estimated population

Question 2

method for the effect of a factor (LIGHT INTENSITY) on the amount of daises

Answer 2

• place a tape measure at the base of the tree
• place a quadrat at the base of the tree
• use a light meter to measure light intensity
• move quadrat 1m down the transect and repeat the measurements
• do this until at the end of the tape measure
  (greater number of daises as you move away from the tree because under the tree there is a lower light intensity and plants need light to PHOTOSYNTHESISE and trees absorb a lot of mineral ions and water from the soil so it is not the only abiotic factor affecting the number of daises)