The A.P. Environmental Science course is interdisciplinary and embraces a wide variety of topics from different areas of study. There are several unifying themes that cut across the many topics included in the study of environmental science. The following themes provide a foundation for the structure of the AP Environmental Science course: (1) Science is a process, (2) Energy conversions underlie all ecological processes, (3) The Earth itself is one interconnected system, (4) humans alter natural systems, (5) Environmental problems have a cultural and social context, and (6) human survival depends on developing practices that will achieve sustainable systems. The course includes lectures, demonstrations, discussions, research projects, probes, in-class assignments, homework, hands on labs and fieldwork are all methods of instruction.