U3 Key Area 2- Distubution Of Organisms

Question 1

What equipment is used for soil moisture/ ph

Answer 1

Moisture/ph level

Question 2

What are two sources of error for measuring soil moisture/ ph (2)

Answer 2

-probe not left long enough to monitor the moisture/ph level
- sample left on probe from previous measurement

Question 3

What are two ways to minimise soil moisture/ ph error (2)

Answer 3

-leave the probe in the soil at the same depth for a few seconds before taking the reading
- wipe the probe between each reading

Question 4

What equipment is used for light intensity?

Answer 4

Light meter

Question 5

What are the sources of error when measuring light intensity (2)

Answer 5

-standing in the way of the light and casting a shadow on a light meter
- light intensity may change throughout the day

Question 6

How can you minimise light intensity errors (2)

Answer 6

• dont stand in front of the sensor/ hold at arms length
• take readings at the same time of day and take several reading for reliability.

Question 7

What equipment is used to measure temperature

Answer 7

Thermometer

Question 8

What are the sources of error for measuring temperature (2)

Answer 8

• thermometer not left in position long enough to monitor the temperature
• temperature may change throughout the day

Question 9

How do you minimise temperatures error (2)

Answer 9

• allow the thermometer to settle before taking the reading
• take readings at the same time of day and take several readings for reliability.

Question 10

What are quadrants used for

Answer 10

To sample plants and very slow moving animals

Question 11

What is the method for using a quadrat (3)

Answer 11

1. Quadrants should be placed randomly so that a representative sample is taken.
2. The number of squares where the organism is present is counted
3. Replicate to give a representative sample of the area.

Question 12

What are the limitation of using a quadrat (2)

Answer 12

• can only be used for stationary or slow-moving organisms
• it depends largely on human accuracy

Question 13

What’s are pit fall traps used for

Answer 13

To sample small living organisms living on soil surface

Question 14

What is the method of pitfall traps (4)

Answer 14

• bury a container with drainage holes, level withe the ground. Traps can be baited
• protect the trap from rain by placing a piece of raised wood or slate above the trap
• leave the trap overnight
• replicated to give a representative sample of the area.

Question 15

What re the limitation of a pit fall trap (4)

Answer 15

• only traps ground fauna
• easily disturbed
• often low catch per trap
• time required to bury trap

Question 16

What are the sourced of error for a quadrat (2)

Answer 16

• non- random sampling
• incorrect counting/ identification

Question 17

How can we minimised quadrats errors (2)

Answer 17

• quadrats should be placed randomly so that a representative sample is taken
• only count squares where organisms is present

Question 18

What or the sources of error in a pitfall trap (2)

Answer 18

• predation occurs
• traps floods

Question 19

How can we minimised the pit fall traps errors (2)

Answer 19

• ensure trap is covered
• drainage holes

Question 20

What does a line transect study measure

Answer 20

The abundance of organisms and abiotic factors along a straight line.

Question 21

What is the method of a line transect study (2)

Answer 21

• a length of string is pegged from area X to Y. The string id marked at one metre intervals
• samples are taken to each one meter interval along the line.

Question 22

What does the line transect study information determine

Answer 22

The effect of an abiotic factors along a on the distribution of an organism

Question 23

What are indicator species

Answer 23

Indicator species are organisms that indicate the levels of pollution or environmental quality

Question 24

How do indicator species indicate levels of pollution

Answer 24

They do this by their presence or absence in the environment