The word ecology is derived from the Greek oikos, "household," and logos, "reason," thus indicating the logic of living creatures in their homes. Although oikos originally indicated only human households, as a term coined in 1866 by Ernst Haeckel, ecology names a biological science such as molecular biology or evolutionary biology, though often thought to be less mature, that studies organism–environment relations. Closely related to ecology in this sense are conservation biology and environmental science. Ecology, the science, studies ecosystems at multiple levels and scales in space and time. Ecosystems have proved to be often quite complicated and resist analysis. Experiments in the field are difficult, and the systems may be partly chaotic.

In part because of such complications ecology has become the focus of a particular set of discussions related to science, technology, and ethics. The term ecological ethics may, for instance, call for doing ethics in...