constant body temperature by basking in the sun or resting in the shade.
Homeostasis: steady state. Conditions may fluctuate widely in the external
environment, but homeostatic mechanisms regulate internal conditions, resulting
in much smaller changes in the animal’s internal environment.
Both birds and mammals have control systems that keep body temperature
within a narrow range, despite large changes in the temperature of the
The internal environment of an animal always fluctuates slightly.
Homeostasis is a dynamic state, interplay between outside forces that tend
to change the internal environment and internal control mechanisms that
oppose such changes.
Negative Feedback: change in some variable triggers mechanisms that reverse to
set the thermostat at comfortable temp = SET POINT
sensor in thermostat