RP 12: Distribution Of Daisies

Question 1

How?

Answer 1

1) Divide 2 areas into grids –> place 2 tape measures at right angle

2) Generate pair of co-ordinates using random generator

3) Place quadrat there and count number of daisies in quadrat

4) Repeat 10+ times and calculate mean per quadrat

5) Measure environmental factor in each area (eg. Soil moisture)

Question 2

Suggest why percentage cover may be used instead of frequency

Answer 2

Too difficult to count individual organisms –> may be too small

Question 3

Why random sampling?

Answer 3

Avoid sample bias

Question 4

Explain importance of large sample size

Answer 4

1) Minimise effect of anomalies

2) Ensure sample is representative of population

Question 5

How can you decide the number of quadrants to use in order to collect representative data?

Answer 5

1) Calculate running mean
2) When enough quadrats show little change
3) Enough to carry out a stats test

Question 6

How to investigate effect of a factor on distribution of species in a habitat (systematic sampling)?

Answer 6

1) Place transect line across area with environmental gradient (eg. Tree to full sun)

2) Place quadrats at regular intervals and record number of organisms of daisies and light intensity using light intensity meter

3) Repeat in other parallel areas and calculate mean number of daisies going along transect

Question 7

Limitations of systematic sampling

Answer 7

1) Not appropriate unless there’s an environmental gradient

2) Transect runs in one direction –> to cover entire field would need different directions

Question 8

Which statistical test to test relationship between abundance and environmental variable?

Answer 8

Spearman’s rank