US Geological Survey
Usgs: Earth Surface Dynamics (Research Activities)
This site from USGS provides several activities to help understand the interrelationships among earth surface processes, ecological systems, and human activities. Also included are links to new findings and programs concerning Earth...
US Geological Survey
Usgs: Desert Ecosystems
What elements are present in a desert ecosystem? What impact might humans have upon it? Learn more about the processes that affect desert ecosystems by visiting this site. Contains only one large illustration.