Homeostasis is the ability of an organism to maintain a stable, constant internal environment, even when the external environment changes. Humans maintain homeostasis in processes such as controlling temperature, blood pressure and respiration as well as maintaining a balance in pH and electrolytes.
Species fit into the classes of conformers or regulators. Regulators have the ability to maintain certain parameters without regard to the environment. Mammals who are regulators maintain a constant body temperature across a large range of ambient temperatures, by perspiring to provide cooling or increasing metabolism to provide heat. Snakes, who like other reptiles are conformers in terms of body temperature, lie on warm rocks in the morning to increase their body temperature. This behavioral adaptation gives them some control over their environment, but they are unable to maintain homeostasis in regard to this function.
The autonomic regulatory system, which maintains homeostasis, comes with a price. It requires energy in the form of food. Because snakes do not maintain body temperature, they are able to survive with a single meal per week, according to Reference.com. In organisms that maintain homeostasis, aging affects the body's ability in controlling the parameter. In humans, this loss of ability leads to disease, including diabetes, gout, dehydration and hypoglycemia.