Importance of Homeostasis The idea that an organism is able to keep its internal environment within a relatively narrow range of change was first proposed around 1850 by the French physiologist Claude Bernard. From his research. Bernard noticed that organisms were able to regulate physiological conditions such as body temperature and water content. He came to the conclusion that an organism would be less affected by a fluctuating environment if it was able to keep its internal environment constant. Another physiologist walter Cannon, found that hormones enabled the body to react to emergencies. From this. he formulated his Homeostasis Theory that the body is able to maintain a stable internal environment because of the interaction of various physiological processes. Homeostasis refers to the maintenance of a constant and stable internal environment of an organism Figure 9.1 shows how external changes are moderated by various mechanisms in the body. As a result, the internal environment fluctuates but within limits which the cells can tolerate. The homeostatic mechanisms typically consist of several parts. internal external environment environment