3.3 sampling techniques and measurement of abiotic and biotic factors

Question 1

What are indicator species and how can they be used to monitor pollution?

Answer 1

indicator species are organisms that indicate the quality of an environment as some species can only thrive in certain conditions
e.g. some species will only thrive in highly polluted conditions

Question 2

Explain the limitations and errors that occur when using.a quadrat

Answer 2

• if the quadrat is too small it may miss too many species
• people may be inconsistent in the counting of organisms -the results may not truly be random
• there may not be enough samples taken for the size of the area

Question 3

name two types of sampling and stare their uses

Answer 3

pitfall traps
-used to trap and count organisms in a soil ecosystem
quadrats
-used to sample plants or slow moving animals
e.g. shell fish on a rocky shore

Question 4

What are quadrants used for and how do you use them properly?

Answer 4

they are used to sample plants or slo moving organisms. When the quadrants are thrown they should be thrown completely randomly

Question 5

How do you measure soil moisture?

Answer 5

it is measured using a moisture meter. The probe is pushed into the soil

Question 6

What are common errors and how would you minimise these errors when using a moisture meter?

Answer 6

• a common error is the probe is not dried after each use and is not being pushed down the same depth each time.
• A way to avoid the would be dry the probe after each use and measure the depth you want to push the probe in and use this depth every time

Question 7

How do you minimise errors when using a quadrat?

Answer 7

• use large quadrants

- use protocols to count organisms

Question 8

How do you measure light intensity?

Answer 8

-using a light meter-the light sensor is pointed at the light source

Question 9

What are common errors and how do you minimise these errors when using a light meter?

Answer 9

• a common error would be pointing the light sensor et the wrong location or covering the light sensor completely
• a way to avoid this would be to double check every time that the sensor is facing the correct direction

Question 10

How do you estimate the abundance of organisms in a field?

Answer 10

• sample the area at random
• average number of organisms in the sample
• average number of organisms in 1m^2
• area of the field in m^2
• multiple the average number of organisms per m^2 by the area of the field

Question 11

What are pitfall traps used for and how do you use them properly?

Answer 11

• they are used to trap and count organisms in a soil ecosystem
• you should put leaves in and/or bark in the bottom to help keep the animals alive
• provide a form of shelter from the rain-e.g. a slanted roof

Question 12

What are the limitations and errors that can occur when using a pitfall trap?

Answer 12

• if they are not checked regularly then predation can occur within the trap
• if a roof/shelter is not provided then organisms may drown in rain water

Question 13

What is an abiotic factor?

Answer 13

a non-living condition that affects the growth and distribution of organisms in an ecosystem

Question 14

Give examples of abiotic factors

Answer 14

• light
• moisture
• temperature
• pH
• wind speed
• oxygen availability

Question 15

How do you measure temperature and what are common errors and how to minimise them?

Answer 15

• thermometer

- heating up the thermometer with your hand

Question 16

How do you measure pH, what common errors are there and how do you minimise these errors

Answer 16

• soil pH meter

- not cleaning the probe after each use