Included in this module are four activities dealing with ecology and applications of ecological principles in the urban environment. Activities included are: (1) the study of ecology; (2) study of consequences of activities within an ecosystem; (3) environmental impacts--benefits and detriments; and (4) choices for the future. Also included are an overview, teacher background information, an activity preview, and a pretest. A module evaluation form and a script for a slide series on Allegheny County, Pennsylvania are also included. (RE)