Paper 2 Practicals

• Measuring the abundance of daisies in a field

  1. Place 2 tape measures at right angles
  2. Use a random number generator to find a set of coordinates and place the quadrat at that point
  3. Count the daisies and record the results
  4. Repeat a large number of times and calculate the mean number of daisies per quadrat
  5. Total no. Of daisies= area of field/area of quadrat X Average number of daisies per quadrat
• Transects

  1. Put the 30m tape measure in a line from the base of a tree to an open area of ground
  2. Put the quadrat against the transect line. One corner of the quadrat should touch the 0m mark on the tape measure.
  3. Count the number of plants inside the quadrat
  4. Use the light meter to measure the light intensity
  5. Record your results in a table
  6. Repeat every 2m
• Extracting DNA from a kiwi fruit

  1. Fill 1/4 of a boiling tube with mashed kiwi fruit - mash to break cell walls and increase surface area
  2. Add mixture of salt and washing liquid - to dissolve membranes, Salt to help precipitation - binds to the DNA and helps it become insoluble
  3. Mix well and put it in the water bath for 20 minutes at 60*C
  4. Filter
  5. Into the filtrate, pour ice-cold ethanol down the side: Don’t Mix - DNA is insoluble in alcohol so forms a precipitate
• Reaction Time

  1. One person holds a ruler vertically, the other positions their thumb and forefinger at the 50cm mark without touching
  2. Without warning, the holder releases the ruler
  3. Catch the ruler as quickly as possible and note the cm mark where it's caught
  4. Convert the distance to reaction time using a standard table
  5. Repeat for accuracy, switch roles and compare results