This paper is based on a study of how students' read nature in different ecosystems. Its focus is on ecology and the context is outdoors. This literacy has to do with an ability to recognise organisms and relate them to material cycling and energy flow in the specific habitat that is to be read. A teaching sequence was designed in order to develop a class of secondary students' ability to read nature in a forest ecosystem. After instruction they were taken to another ecosystem, a pond where they were asked to read the new environment. The main goal was to follow to what extent they can transfer their understanding from one ecosystem to another. The study is based on recorded interviews, field work, and classroom activities, and it shows the importance of learning general patterns in nature and relating them to functional groups of organisms in an ecosystem. (Contains 14 figures.)