ST 2. Distribution of Organisms N5 (LOE) Flashcards
What are biotic factors?
Biotic factors are living factors
What are abiotic factors?
Abiotic factors are non living factors
What are some biotic factors?
Competition for resources, disease, food availability, grazing and predation
What are some abiotic factors?
Light intensity, moisture, pH and temperature
What can abiotic and biotic factors affect?
Abiotic and biotic factors can affect the distribution of organisms
What can warm temperature do?
Warm temperatures in an ecosystem can increase biodiversity
What can low levels of grazing do?
Low levels of grazing can decrease the biodiversity in an ecosystem
How is light intensity measured?
Light meter
How is a light meter used?
A light meter is used by holding the sensor upwards and a reading is taken from the scale. The light sensor may be inadvertently shaded so it is important to ensure all users stand clear
How are pH and soil moisture measured?
pH and soil moisture are measured using a pH meter or moisture meter
How are pH and soil meters used?
The probe is inserted into the ground and a reading is taken from the scale. The probe on the meter may retain soil from a previous sample so it is importantly to wipe the probe between reading
KEY POINTS
- Insert probe into ground
- Wipe probe between uses
How is temperature measured?
Temperature is measured using a thermometer
How is a thermometer used?
The thermometer is placed in an open area and a reading is taken from the scale. Placing the thermometer in direct sunlight or holding it in a warm hand may provide an inaccurate reading so it is important to place the thermometer in a shaded area
KEY POINTS
- Place in open area
- Avoid placing thermometer in sunlight
- Avoid holding in warm hand
- Place in shaded area
How are quadrats used?
Quadrats are thrown randomly and the number of squares containing the organism of interest are counted. Quadrats only sample a small proportion of the investigated area therefore it is important to throw the quadrat randomly, several times and calculate an average
KEY POINTS
- Throw randomly
- Only sample small proportion
- Calculate an average
How are pitfall traps used?
Pitfall traps are sunk into the ground and camouflaged to allow invertebrates to fall in. It is important to ensure the trap is level with the soil and camouflaged so insects will fall in.
KEY POINTS
- Sunk into ground
- Invertebrates are captured
- Trap must be level with soil
- Camouflaged
