experience temperature extremes. Yet the temperature of their body affects their
life functions -- too hot and the proteins in their body breakdown (eventually
leading to death); too cold and their body functions slow down. Thus plants
and animals have various strategies to regulate their body temperature for optimum
Hoff's Rule: for every temperature rise of 10 degrees C, rate of biochemical
reactions (most body functions) doubles, up to a point (when proteins break
all energy taken in by plants and animals is portioned out to the following
areas -- growth, reproduction, activity, maintenance, and storage. Savings
in one area (e.g., maintenance which includes thermoregulation) means more
energy can be diverted to other areas (e.g., storage for hard times later).
using posture, orientation, and microclimate selection to regulate body temperature.
For example, a lizard that wants to heat up will spread eagle (posture) on
the top of a hot rock (microclimate) and turn its entire back to the sun (orientation).
altering metabolic generation of heat to regulate body temperature.
of Animals based on means of thermoregulation:
animals whose principal source of body heat is the environment. Includes essentially
all animals except birds and mammals.
animals whose principal source of body heat is from their own body generating
heat metabolically. Birds and mammals are endotherms.