Date | May 2016 | Marks available | 3 | Reference code | 16M.3.SL.TZ0.14 |
Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
Command term | Outline | Question number | 14 | Adapted from | N/A |
Question
Primary plant succession has been observed in sand dunes adjacent to the northern end of Lake Michigan, one of the Great Lakes in North America. The youngest sand dunes have beach grass (Ammophila breviligulata) and prairie bunch grass (Schizachyrium scoparium). The oldest dunes have coniferous trees (Pinus strobus and Pinus resinosa).
Predict the differences in the soil characteristics between the youngest and oldest sand dunes.
Outline how the type of stable ecosystem that will develop in an area can be predicted based on climate.
Markscheme
«In the older sand dunes you would expect» (Accept inverse answers related to younger sand dunes)
More complex deeper soil
Buildup of organic matter
Better water retention
Higher nutrient content
Support larger diversity of soil organisms
Soil is less likely to be blown away
OR
Soil is more stable
A different pH
Climate is defined by temperature and rainfall
Absence of rainfall/water/humidity leads to desert
Moderate amount of rainfall leads to grassland
High levels of rainfall leads to forest
Temperature determines type of grassland/forest
Examiners report
Most candidates could give the differences in the soil but many attributed the older dune characteristics to the younger dunes.
Mixed responses but most could outline how ecosystems can be predicted based on climate.