Date | May 2018 | Marks available | 3 | Reference code | 18M.3.SL.TZ1.14 |
Level | Standard level | Paper | Paper 3 | Time zone | Time zone 1 |
Command term | Suggest | Question number | 14 | Adapted from | N/A |
Question
A retreating glacier leaves an environment of lifeless glacial deposits, including sands and gravels. Retreating glaciers often offer suitable sites for primary succession.
[Source: climatica.org.uk]
Predict the process of succession that takes place on exposed bare ground as the glacier retreats.
Suggest how human activities could impact the development of an ecosystem on exposed bare ground.
Markscheme
a. (bare ground) colonized by microorganisms/pioneer species
b. thin soil forms from rock fragments/decomposing organisms
c. soil retains water (from melting permafrost/ice)
d. grasses/small plants/herbaceous plants/grow
e. (larger plants) create habitats for animals
f. weather/climate may limit plant size/biodiversity
OR
climax community forms
a. buildings/roads/walking prevent plant cover/soil development/cause soil erosion
b. may destroy moss/soil organisms / damage emerging vegetation
c. introduce alien species
d. rubbish/solid waste/pollution may impede natural development
e. feces/excrement may contribute to/alter soil development / add fertilizer/pesticides to increase growth of plants
f. sow seeds/planting and so alter diversity
g. irrigation/drainage to affect growth