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Lichen species grow on trees and are air quality indicators - Edexcel - GCSE Biology - Question 5 - 2013 - Paper 1
Question 5
Lichen species grow on trees and are air quality indicators. The table shows the sulfur dioxide concentrations in three areas (A, B and C). Each area contained 100... show full transcript
Worked Solution & Example Answer:Lichen species grow on trees and are air quality indicators - Edexcel - GCSE Biology - Question 5 - 2013 - Paper 1
Step 1
Calculate the difference in the number of trees in area A and area C with lichen growing on them.
Answer
To find the difference in the number of trees with lichen between area A and area C, we can use the data provided:
- Number of trees in Area A with lichen: 204
- Number of trees in Area C with lichen: 14
Now, subtract the number of trees in Area C from Area A:
Thus, the difference in the number of trees in area A and area C with lichen growing on them is 190.
Step 2
Describe the effect of sulfur dioxide on the number of lichen.
Answer
An increase in sulfur dioxide concentration negatively impacts the number of lichen growing on trees. Specifically:
- In Area A, which has a higher sulfur dioxide concentration of 5 ppm, 204 trees had lichen.
- In Area C, with an even higher concentration of 15 ppm, only 14 trees had lichen.
This indicates that as the concentration of sulfur dioxide increases, the number of lichen decreases. Thus, sulfur dioxide acts as a pollutant, detrimental to lichen growth.