Paper 2 H - SAMPLE SET 1 Q16 Answers
16) Some students are investigating lichens.
Lichens are often studied because they are sensitive to pollution.
(a) Lichens are made up of two different organisms: a fungi and algae.
Both the fungus and the algae gain from living together.
What biological name is given to a relationship where both organisms gain? [1]
(b) The students find a diagram of a lichen.
Lichens are often studied because they are sensitive to pollution.
(a) Lichens are made up of two different organisms: a fungi and algae.
Both the fungus and the algae gain from living together.
What biological name is given to a relationship where both organisms gain? [1]
(b) The students find a diagram of a lichen.
Using the information from the diagram suggest what the algae and fungi each gain from their relationship. [2]
algae ……………………………………………………………………………………………...
fungus …………………………………………………………………………………………....
(c) Lichens are sensitive to pollution because they take up chemicals from the air.
The diagram shows a ‘bushy’ species of lichen and a ‘crusty’ species of lichen.
algae ……………………………………………………………………………………………...
fungus …………………………………………………………………………………………....
(c) Lichens are sensitive to pollution because they take up chemicals from the air.
The diagram shows a ‘bushy’ species of lichen and a ‘crusty’ species of lichen.
Bushy lichens are usually more sensitive to pollution than crusty lichens.
Use the diagrams to suggest why. [1]
(d) The students decide to use lichens to try and work out how polluted their school grounds are.
They read about a scale called the Lichen Diversity Value (LDV).
It is worked out in this way:
(ii) The students put their results into a table.
Use the diagrams to suggest why. [1]
(d) The students decide to use lichens to try and work out how polluted their school grounds are.
They read about a scale called the Lichen Diversity Value (LDV).
It is worked out in this way:
- choose four trees in the area
- hold a quadrat on the north side of the trunk of one tree
- count the total number of all the lichens in the quadrat
- then do this on the east, south and west side of the tree
- repeat this for each tree.
(ii) The students put their results into a table.
The LDV is found by adding together the four mean values.
The students calculate the mean number of lichens on the north, east and south sides of the trees.
Calculate the mean for the west side and use this to calculate the LDV. [2]
The students calculate the mean number of lichens on the north, east and south sides of the trees.
Calculate the mean for the west side and use this to calculate the LDV. [2]
LDV = ............................
(iii) This scale shows the diversity of the lichens shown by the LDV.
What does the LDV show about the diversity of lichens in the school grounds? [2]
(iv) LDV is calculated by counting all the lichens present. What else about the lichens could the students look for to make a better assessment of pollution? [3]
(Total for Question 16 = 12 marks)
(iv) LDV is calculated by counting all the lichens present. What else about the lichens could the students look for to make a better assessment of pollution? [3]
(Total for Question 16 = 12 marks)