A number of very different conceptual approaches have been employed in human ecology. This report reviews several of the most important analytic frameworks: environmental determinism and possibilism, cultural ecology, the ecosystem-based model, and the actor-based model. The contributions made by each conceptual approach to increasing understanding of human ecology are described, and their strengths and weaknesses are assessed. Finally, an alternative conceptual approach -- the systems model of human ecology -- is proposed. In this interactive model, the human social system is seen as being linked to its ecosystem through the interchange of energy, materials, and information.