Sampling techniques

Question 1

what is the capture recapture technique used for?

Answer 1

to estimate the size of an animal population

Question 2

describe the capture recapture technique

Answer 2

1. capture organisms from sample area, mark, and release
2. at a later date recapture organisms in the original sample area
3. record the number of marked / unmarked individuals

Question 3

what is the equation used for the capture recapture technique?

Answer 3

(1st sample size x 2nd sample size) / number of recaptured marked specimens

Question 4

describe quadrats

Answer 4

-individuals that are found in the quadrats are identified and counted
-from the data a mean can be calculated and this information can be scaled up to estimate the population over a larger area

Question 5

describe random sampling

Answer 5

-individuals are selected by chance
-mark out a grid and use a random number generator to select coordinates

Question 6

what is random sampling used for?

Answer 6

to compare abiotic factors or to look at abundance / biodiversity

Question 7

what is non random sampling used for?

Answer 7

to study the distribution of organisms change over a distance e.g. up a rocky shore

Question 7

describe non random sampling

Answer 7

samples are taken at fixed positions along the line using a quadrat

Question 8

transect

Answer 8

cuts across the environmental gradient

Question 9

what are the different types of non random sampling?

Answer 9

-line transect
-belt transect
-interrupted belt transect

Question 10

describe line transect

Answer 10

a tape line is placed and any plant species that touch the tape are counted

Question 11

describe belt transect

Answer 11

quadrats are placed alongside the tape one after the other with no gaps inbetween

Question 12

describe interrupted belt transect

Answer 12

quadrats are placed in regular intervals beside the tape with space inbetween