Biology Practicals: Summary
A2 BIOLOGY CORE PRACTICAL SUMMARY
Name of practical Independent & dependent variables
Observing patterns by Ecological sampling Random sampling Systemic sampling
Other variables to be controlled
Abiotic factors e.g. light, temperature, soil water, humidity, O2 concentration, pH, aspect, slope angle
equipment
Gridded Quadrat Tape measure Point quadrat Pitfall trap Sweep Net Pooter Tullgren funnel Baermann funnel
Method and outcome
Several methods. 1 random sampling = set up grid using tape measure, use random numbers to generate points to place quadrat to collect data. 2 systemic sampling = line transect often used especially to study zonation. A tape measure is laid along several zones to be looked at and quadrats are used to record data at regular intervals 3 Measuring abundance Density = presence of organisms per quadrat Frequency = percentage of quadrat squares containing organism Percentage cover = percentage of ground covered with organism in a quadrat (usually for plants) Pitfall trap = to collect invertebrates Sweep net = to collect invertebrates in long grasses Pooter = to collect invertebrates into a container Tullgren funnel = to collect organisms from soil or leaf litter Baermann funnel = to collect living organisms from water Decide on a range of temperatures from 5 °C to 35 °C to be tested. Place 2 g of sea salt into a 100 cm3 beaker. Add 100 cm3 of de-chlorinated water and stir until the salt completely dissolves. Label the beaker with sea salt and the temperature at which it will be incubated. Place a tiny pinch of egg cysts onto a large sheet of white paper. Wet the piece of graph paper using a few drops of salt water. Dab the paper onto the white sheet to pick up approximately 40 eggs. Use a magnifying glass to count the eggs. Put the paper with the 40 eggs into the beaker (eggs-side down). After 3 minutes, use a pair of forceps to gently remove the paper, making sure that all the egg cysts have washed off into the water. If possible
Name of practical Independent & dependent variables
Observing patterns by Ecological sampling Random sampling Systemic sampling
Other variables to be controlled
Abiotic factors e.g. light, temperature, soil water, humidity, O2 concentration, pH, aspect, slope angle
equipment
Gridded Quadrat Tape measure Point quadrat Pitfall trap Sweep Net Pooter Tullgren funnel Baermann funnel
Method and outcome
Several methods. 1 random sampling = set up grid using tape measure, use random numbers to generate points to place quadrat to collect data. 2 systemic sampling = line transect often used especially to study zonation. A tape measure is laid along several zones to be looked at and quadrats are used to record data at regular intervals 3 Measuring abundance Density = presence of organisms per quadrat Frequency = percentage of quadrat squares containing organism Percentage cover = percentage of ground covered with organism in a quadrat (usually for plants) Pitfall trap = to collect invertebrates Sweep net = to collect invertebrates in long grasses Pooter = to collect invertebrates into a container Tullgren funnel = to collect organisms from soil or leaf litter Baermann funnel = to collect living organisms from water Decide on a range of temperatures from 5 °C to 35 °C to be tested. Place 2 g of sea salt into a 100 cm3 beaker. Add 100 cm3 of de-chlorinated water and stir until the salt completely dissolves. Label the beaker with sea salt and the temperature at which it will be incubated. Place a tiny pinch of egg cysts onto a large sheet of white paper. Wet the piece of graph paper using a few drops of salt water. Dab the paper onto the white sheet to pick up approximately 40 eggs. Use a magnifying glass to count the eggs. Put the paper with the 40 eggs into the beaker (eggs-side down). After 3 minutes, use a pair of forceps to gently remove the paper, making sure that all the egg cysts have washed off into the water. If possible