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.

«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

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.