P2 required practicals Flashcards
1
Q
How to investigate the effect of light in the growth of seedlings
A
- Set up 3 petri dishes containing cotton wool soaked in equal amounts of water
- Put 10 seeds in each dish
- Put the dishes in a warm place
- Allow the seeds to germinate, water daily with equal amounts of water to each dish
- Remove excess seedlings from any dish that has too many, to make sure all dishes have same amount of seedlings
- Measure the height of each seedling in mm
- Move 1 petri dish on a windowsill in full sunlight, one in partial light and the 3rd one in darkness
- 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
2
Q
How to measure the population size of a common species in a habitat (not random)
A
- Place a 30m tape measure across the habitat to form a transect line
- Place the 1m^2 quadrat against the transect line so one corner of it touches the 0m mark on the tape
- Count the number of the species in the quadrat
- Record the number of species counted in a table
- 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
3
Q
How to measure the population size of a species in a habitat (random)
A
- Place 2 20m long tape measures next to each other at right angles
- 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
- Record the number of the species in the quadrat
- Repeat for a total of 10 different points
- To work out the total population do total area/area samples x number of organisms of that species counted in sample