This unique addition to reference literature provides an introduction to the major concepts and contemporary issues that are essential for students of environmental science and environmental studies to know. With over 200 entries authored by world-class names like Anthony Brazel, John Day and Edward Keller, this text is divided into six sections: Environmental Science, Environments, Paradigms & Concepts, Processes & Dynamics, Scales & Techniques, and Environmental Issues.
In a system, if inputs are equal to output, then the system is said to be in a steady state or in equilibrium. But this is a dynamic equilibrium because material is entering the system and leaving the system, but at equal rates. For example, over a day or two, a person's weight will generally change very little, if at all. But food is being consumed, digested, and turned into carbon dioxide as oxygen is consumed. This is a dynamic steady state. Such a steady state can occur at many different levels of organization, from the whole earth to a single organism. Larger scales can be considered, the solar system for example, and smaller scales such as a single cell.
[Page 177]For example, over a period ...