RP9 - Field Investigation

Question 1

How would you use random sampling to estimate the population size of a plant species?

Answer 1

● Create a grid of the area using tape measures
● Use a random number generator to generate coordinates
● Set down quadrat at coordinates and record number of required
species within quadrat
● Repeat using many sampling sites
● Estimate population size: area sampled / total area x number of
plants species counted

Question 2

Why would you use a random number generator to determine coordinates?

Answer 2

To avoid bias and obtain representative results

Question 3

What is random sampling?

Answer 3

Sampling technique in which each sample has an equal probability of being chosen

Question 4

What is systematic sampling?

Answer 4

Sampling technique where there is a fixed, periodic interval between consecutive samples

Question 5

Describe how you would use continuous sampling to investigate the effect of an abiotic factor in the distribution of a plant species

Answer 5

● Create hypothesis on the effect of the change in an abiotic factor on the distribution of a plant species
● Lay tape measure along an area with an ecological gradient
● Place quadrat at start and count number of plants
● Repeat at 5m intervals along the transect
● Record the value of the abiotic factor eg. light intensity at each sampling site
● Produce a graph of plant numbers (y) against the abiotic factor (x)