The nonfiction Reader for Unit 11, entitled Introduction to Ecology, consists of selections that will further students’ understanding of habitats and ecosystems, the environment, and food chains. Aspects of ecosystems and the balance of nature are explained as well as producers, consumers, and decomposers in food chains. In addition, how the environment changes both naturally and as a result of human actions is described. Later chapters focus on protecting and preserving the environment and important natural resources. A biography of John Muir is also included.