Unit 2.1b

Question 1

Why is sampling important?

Answer 1

Allows a representative sample of a habitat and reduces impact on habitat and species.

Question 2

What is random sampling?

Answer 2

Sampling that gives members of population equal chance of selection. Effective in large uniformly distributed groups. Straight forward, no bias but gives poor representation overall.

Question 3

What is stratified sampling?

Answer 3

Entire population divided into sub-groups and final subjects randomly selected in proportion to groups. Highly representative overall but requires researched to know group proportions prior and data must be up-to-date.

Question 4

What is systematic sampling?

Answer 4

When members of a population are selected at regular intervals. Provides representative sample overall but not an equal chance of selection and subject to bias.

Question 5

What are the 4 main sampling techniques?

Answer 5

Transects, capture, point counts and elusive species.

Question 6

What is a transect?

Answer 6

Line along terrain where samples can be taken.

Question 7

Where should a transect be placed? (2 examples)

Answer 7

Where the terrain is changeable (ie. woodland to field) or where abiotic factors can be measured (ie, plant abundance, slow moving organisms)

Question 8

What two sampling devices can be placed along a transect?

Answer 8

Meters for pH, moisture light (measures abiotic factors)
Quadrats

Question 9

What are the two capture techniques?

Answer 9

Trapping and netting

Question 10

What do capture techniques usually sample?

Answer 10

Mobile organisms

Question 11

What is the most simple trapping system and what is it used for?

Answer 11

Pitfall traps
Used to capture invertebrates on the ground

Question 12

What trap captures flying insects?

Answer 12

A pan trap

Question 13

How do pan traps work?

Answer 13

Shallow dish that is brightly coloured to attract insects
Filled with liquid of low surface tension (ie. soapy water) to drown them in.

Question 14

Where can sweep netting be used and how does it work?

Answer 14

Air
Net is swept through air and and is grasped to prevent any insects caught from escaping
Water
Net is built so when swept through water, water is allowed to flow through but insects are caught

Question 14

What trapping device catches birds?

Answer 14

Large mist nets

Question 15

What trap catches flying insects and how does it work?

Answer 15

Flight interception traps, which are a screen of black or white mesh

Question 16

How are large animals captured?

Answer 16

No specific method as set up according to the type of animal, can use baiting and might involve tracking or sedation

Question 17

What is point count sampling

Answer 17

Sampling used for bird populations in an area for a prolonged period of time

Question 19

How is point sampling conducted?

Answer 19

Birds seen or heard from a stationary point over a period of time are recorded

Question 20

What does point count sampling allow?

Answer 20

Bird populations to be compared throughout the year

Question 21

What are the three techniques used to sample, elusive species?

Answer 21

Camera trapping, scat sampling, remote sensing

Question 22

What does a good sample allow?

Answer 22

Extrapolations- prediction made on the whole population