The purpose of this booklet is to bring into the classroom the ecological processes and principles that underlie nature. Students get the opportunity to work with natural objects and to learn about the principles that regulate them. In this revised edition, a number of publications have been compiled and printed under one title. The booklet is designed to help the teacher by supplementing existing programs with these student-oriented activities. The information includes simple directions on how to build a number of different terrestrial and aquatic microenvironments, as well as the ecological principles behind their construction and maintenance. All materials are common and easily purchased, including the contents of the terrariums and turtle ponds. There are a number of diagrams and photographs to illustrate the procedures and principles being discussed. (MA)