Types Of Sampling

Question 1

Sampling

Answer 1

Taking measurements of a limited number of individual organisms present in a particular area

Question 2

What can sampling be used for ?

Answer 2

• estimate the number of organisms in a area
• the abundance of the organism
• measure a particular characteristic of an organism

Question 3

Random sampling

Answer 3

The positions of the sampling points are completely random or due to chance

ADVANTAGE : there will be no bias by the person carrying out the sampling that may affect the results

Question 4

Non - random sampling

Answer 4

Positions of the sampling points are chosen by the person carrying out the sampling

DISADVANTAGE: person choosing could show bias towards or against certain areas
Eg. Individuals may deliberately place the quadrat in areas with the least species as these will be easier and quicker to count

UNREPRESENTATIVE of the whole area

Question 5

Abundance of species

Answer 5

Number of individuals of that species

Question 6

Distribution of a species

Answer 6

How it is spread throughout the ecosystem

Question 7

Non random sampling 3 main techniques

Answer 7

• opportunistic
• stratified
• systematic

Question 8

Opportunistic sampling

Answer 8

• picking and choosing sampling locations based in various non- random factors
• weakest form as its not representative of the population

Question 9

Stratified sampling

Answer 9

Involves matching the number of sampling locations in a particular habitat with the relative proportion of area that habitat covers in the whole area being studied

Question 10

Systematic sampling

Answer 10

Used when there is a clear change in the physical conditions across the area being studied

For eg. Change in altitude, soil pH, light intensity

Methods using transects can help show how species distribution changes with the different physical conditions in that area

Question 11

Transects

Answer 11

Line represented by a measuring tape along which sample are taken

Question 12

Line transect

( often used for systematic sampling )

Answer 12

Making a line along the ground between two poles and taking samples at specified points

Question 13

Belt transect

( systematic sampling )

Answer 13

• Provides more information
• 2 parallel lines are marked and samples are taken of the area between the two lines

Question 14

Sweeping nets

Answer 14

Large strong nets with a fine material with small holes that are used to catch flying insects and insects that live in oomf grass by sweeping the net back and fourth through the grass

Question 15

Pitfall traps

Answer 15

Cans or jars that are buried in the ground that are used to catch ground- dwelling insects and other invertebrates as they fall into the trap

Question 16

Pooters

Answer 16

• Small plastic or glass containers with two tubes sticking out that are used to suck up small insects and other small invertebrates
• 1st tube is placed over the insect and the second tube is used by the scientist to create suction

Question 17

Tullgren funnel

Answer 17

Funnels with a light bulb above and a container below that are used to collect invertebrates that live in leaf litter r soil

Lead little or soil is placed in the funnel and the light and head forces the invertebrates to move down until they drop into the container

Question 18

Kick sampling

Answer 18

• catch freshwater invertebrates living in streams or rivers
• a net is placed on the streamed so that the water is flowing into it and the stream bed just above the net if churned by the scientist for a set period of time
• the invertebrates are carried by the stream into the net

Question 19

Point quadrant

Answer 19

• Consists of a frame containing a horizontal bar
• at set intervals along the bar long pins can be pushed through the bar to reach the ground
• each species or a plant the pin touches is recorded

Question 20

Frame quadrat

Answer 20

• consists of a square frame divided into a grid of equal sections
• the type and number of species within each section of the quadrat is recorded

Question 21

Advantage of using a range of sensors to measure abiotic factors

Answer 21

• rapid changes can be detected
• human error in taking a reading is reduced
• a high degree of precision can be often be achieved
• data can be stored and tracked On a computer

Question 22

Features of habitat in low biodiversity area

Answer 22

• few successful species
• stressful nature of the environment
• few species live in the habitat often with very specific adaptations for the environment
• relatively simple food webs
• major effects on the ecosystem when there is a change

Question 23

Features of habitat features in a high biodiversity area

Answer 23

• large number of successful species
• not stressful nature of the environment
• many species live in the habitat often with few specific adaptations to the environment
• complex food webs
• if there is a change there is a relatively small effect on the environment of the ecosystem