Lichens grow on trees, walls, rocks and soil.
Fig. 9.1 shows a lichen from the genus Usnea. Usnea can withstand only low concentrations of sulfur dioxide and will not grow where the air contains sulfur dioxide pollution.
Usnea consists of a mixture of two cell types:
• photosynthetic cells that belong to the kingdom Protoctista
• fungal cells that belong to the kingdom Fungi.
(a)[4]
Outline the distinguishing characteristics of the kingdoms Protoctista and Fungi.
(b(i))[3]
A student devised a method to assess the relative abundance of Usnea and Xanthoria on trees along a transect from the town centre at $0\,\text{km}$ to unpolluted countryside at $4\,\text{km}$.
Suggest why measuring the relative abundance of the two types of lichen provides information that is useful for conservation.
(b(ii))[2]
Although a wide variety of lichens occur in many habitats, most people overlook them.
Outline why forms of life that are usually ignored, such as lichens, should be conserved.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Both belong to the eukaryotic domain Eukarya” …