biology - 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 sample / total area X number of plant species counted

Question 2

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

Answer 2

To avoid bias and 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 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 transect
• record the value of the abiotic factor