Lesson 12 - Sampling techniques

Question 1

Ethics of collecting living animals:

Answer 1

• Handle for a short period of time
• Must be released back into habitat at the point they were collected.

Question 2

Techniques to collect living animals:

Answer 2

• A pooter –> small insects.
• Sweep nets –> insects in areas of long grass
• Pitfall traps –> crawling invertebrates such as beetles, spiders and slugs.
• Tree beating –> Take samples lining in a tree or bush.
• Kick sampling –> study organisms living in a river.

Question 3

Pooter:

Answer 3

• Small insects
• Suck into mouthpiece, insects drawn into the holding chamber via inlet tube. Filter before the mouthpiece prevents them from being sucked into the mouth.

Question 4

Pitfall traps

Answer 4

• Small, crawling invertebrates (beetles, spiders and slugs)
• Hole is dug into ground, which insects fall into.
• Deep enough that they cannot crawl out, covered with a roof-structure propped above so that trap doesn’t fill with rainwater.
• Traps are left overnight, so nocturnal species also sampled.

Question 5

Tree beating:

Answer 5

• Invertebrates living in tree / bush.
• Large white cloth stretched under tree. Tree is shaken / beaten to dislodge invertebrates. Animals will fall into the sheet where they can be collected and studied.

Question 6

Kick sampling

Answer 6

• Organisms living in a river.
• River bank and bed is ‘kicked’ for a period of time to disturb substrate. Net held downstream for set period in order to capture organisms released into flowing water.

Question 7

Sampling plants:

Answer 7

• Quadrat –> pinpoint an area in which the sample of plants should be collected.
• Samples can also be used to sample slow-moving animals.

Question 8

Types of quadrat:

Answer 8

• Point quadrat –> frame containing horizontal bar. At set intervals, long pins can be pushed through bar to reach ground. Each species of plant the pin touches is recorded.
• Frame quadrat –> consists of a square frame divided into a grid of equal sections. Type and number of species within each section of quadrat is recorded.

Question 9

Valid representative of an area (quadrats)

Answer 9

Random sampling technique

Question 10

Presence and distribution of organisms across an area of land varies (quadrats)

Answer 10

line / belt transect.

Question 11

Measuring species richness:

Answer 11

• Biodiversity species richness is a measure of the number of different species living in a specific area.
• Combination of techniques.
• List of species complied and identified. (Identification keys used - contain images / series of questions)
• Total no. species calculated.

Question 12

Measuring species evenness:

Answer 12

• How close in numbers the populations of each species in an environment are.

Question 13

Using frame quadrats:

Answer 13

• Density –> no. large plants in 1m by 1m quadrat square.
• Frequency –> Individual members of species hard to count. Use small grids within quadrat.
• Percentage cover –> Speed as lots of data collected quickly. Estimate by eye of area within quadrat that species of plan species covers.

Question 14

The larger the number of sample taken…

Answer 14

the more reliable your results.

Question 15

Estimating animal population size:

Answer 15

• Moving / hidden.
• Capture-mark-release-recapture.
• Compare number of marked individuals with the number of unmarked individuals in the second sample –> estimate population size.
• Greater the number of marked individuals recaptured, the smaller the population.

Question 16

How is species evenness expressed:

Answer 16

As a ratio

Question 17

Measuring abiotic factors:

Answer 17

• Range of sensors

Question 18

Advantages of using sensors:

Answer 18

• Rapid changes can be detected.
• Human error in taking a reading reduced.
• High degree of precision can often be achieved.
• Data can be stored and tracked on a computer.

Question 19

Wind speed sensor used and units?

Answer 19

Anemometer –> m s^-1

Question 20

Light intensity sensor used and units?

Answer 20

light meter lx

Question 21

Relative humidity sensor used and units?

Answer 21

Humidity sensor mg dm^-3

Question 22

pH sensor used and units?

Answer 22

pH probe pH

Question 23

temperature sensor used and units?

Answer 23

temperature probe (degrees Celcuis)

Question 24

oxygen content in water sensor used and units?

Answer 24

dissolved oxygen probe mg dm^-3