cp 16

Question 1

IV DV

Answer 1

IV = Chosen Abiotic Factor e.g. Light Intensity, Soil Moisture, Soil Compaction

DV = % Cover or Density

Question 2

Controlled variable

Answer 2

Abiotic factors not being tested should be kept constant where possible e.g. light intensity, moisture/ humidity, soil pH, temperature

Question 3

PROCEDURE

Answer 3

1. idea of using a quadrat ;
2. idea of {random / systematic} sampling (of wall) ;
3. {count number of squares/ determine area} containing lichen /eq ;
4. credit an indication of how the percentage was calculated ;
5. use of random {coordinates / sampling / eq} ;
6. method of generating random coordinates ;
7. description of estimate of abundance e.g. number of plants, percentage cover
8. indication that several sample sites used ;
9. appropriate method of recording quantitative data i.e. graph

PROCESSED

1. plot a (scatter) graph of light intensity against lichen /
2. reference to looking for a correlation ;
3. reference to use of statistics test ;
4. appropriate named test eg Spearman’s rank, Pearson

Question 4

EVALUATION

Answer 4

● It is impossible to completely control all the abiotic factors in the field
● % cover is purely an estimate
● May be difficult to count individual organisms if they are at very high frequency.
● Only suitable for static/ very slow-Moving organisms
● position of transect will have some aspect of bias however there must be a change in the condition being tested as you move along it
● Time of day that abiotic factors are being measured could affect results and so must be measured as closely together as possible, particularly light intensity as this changes throughout the day