Urban Ecosystems 2: Why Are There Cities? A Historical Perspective
4 The Physical Setting
Processes that Shape the Earth
For Grades: 6-8
Learning Goal 7
Human activities, such as reducing the amount of forest cover, increasing the amount and variety of chemicals released into the atmosphere, and intensive farming, have changed the earth's land, oceans, and atmosphere. Some of these changes have decreased the capacity of the environment to support some life forms.