B6.1.1/B6.1.2 - Sampling techniques

Question 1

What does sampling mean?

Answer 1

To take observations or measurements from a small area, which is representative of a large area

Question 2

How can you collect living organisms with Pooters?

Answer 2

You suck on the mouthpiece to draw insects into the holding chamber. There is a filter to prevent it from entering your mouth

Question 3

How can you collect living organisms with Sweep nets?

Answer 3

Sweep a large net through the air to catch flying insects or those in long grass

Question 4

How can you collect living organisms with Kick sampling?

Answer 4

‘Kick’ a river bank or bed to disturb mud and vegetation. Hold a net downstream to capture any organisms released into the flowing water

Question 5

How can you collect living organisms with Tree beating?

Answer 5

Stretch a large white cloth under a tree (or bush) and then shake to beat the tree to dislodge invertebrates, which will fall onto the cloth

Question 6

How can you collect living organisms with Pitfall traps?

Answer 6

Dig a hole in the ground which crawling invertebrates can fall into. Cover the hole with a roof so that the trap does not fill with rain water

Question 7

What is an identification key?

Answer 7

A chart used to identify unknown organisms. Keys ask a series of questions about an organism’s characteristics

Question 8

What are the 2 main types of identification key?

Answer 8

Branched key and Numbered key

Question 9

How does a branched key work?

Answer 9

By answering yes or no for each question you can determines an organism’s identity

Question 10

How does a numbered key work?

Answer 10

The correct answer to a question tells you which question you need to answer next. After answering a series of questions you will identify your unknown organism

Question 11

What is the formula for estimated population size?

Answer 11

first sample size x second sample size / number of recaptured marked individuals

Question 12

How does the capture-recapture technique work?

Answer 12

1. Capture organisms from a sample area
2. Mark individual organisms and release back into community
3. At a later date, recapture organisms in the original sample area
4. Record the number of marked and unmarked individuals
5. Estimate the population size using the formula

Question 13

How can you sample plants?

Answer 13

You can use a quadrat by placing it on the ground to take a sample and record the type and number of organisms within each section

Question 14

What is non-random sampling?

Answer 14

Systematically choosing where to take a sample

Question 15

What is random sampling?

Answer 15

Position of sampling is not pre-determined; individuals are selected by chance

Question 16

What can transects be used for?

Answer 16

To sample across a line, to link changes in a species to abiotic factors, such as immersion in water and light intensity, temperature fluctuations