P2 required practicals

Question 1

How to investigate the effect of light in the growth of seedlings

Answer 1

1. Set up 3 petri dishes containing cotton wool soaked in equal amounts of water
2. Put 10 seeds in each dish
3. Put the dishes in a warm place
4. Allow the seeds to germinate, water daily with equal amounts of water to each dish
5. Remove excess seedlings from any dish that has too many, to make sure all dishes have same amount of seedlings
6. Measure the height of each seedling in mm
7. Move 1 petri dish on a windowsill in full sunlight, one in partial light and the 3rd one in darkness
8. Measure the height of each seedling everyday for at least 7 days
   Record the heights in a table and calculate the mean height of the seedlings each day

Question 2

How to measure the population size of a common species in a habitat (not random)

Answer 2

1. Place a 30m tape measure across the habitat to form a transect line
2. Place the 1m^2 quadrat against the transect line so one corner of it touches the 0m mark on the tape
3. Count the number of the species in the quadrat
4. Record the number of species counted in a table
5. Move the quadrat 5m up the transect line and count the amount of species in the quadrat
   Calculate the mean number of population per m^2
   Repeat moving the quadrat all the way up the transect line

Question 3

How to measure the population size of a species in a habitat (random)

Answer 3

1. Place 2 20m long tape measures next to each other at right angles
2. Use a random number generator to create points in the grid that has been created on the ground with the transects and place the quadrat at the point
3. Record the number of the species in the quadrat
4. Repeat for a total of 10 different points
5. To work out the total population do total area/area samples x number of organisms of that species counted in sample