ACCLIMATIZATION

The process in which an individual organism adjusts to a

gradual change in its environment (such as a change in

temperature, humidity, photoperiod, or pH), allowing it to

maintain performance across a range of environmental

conditions. Acclimation occurs in a short period of time (days

to weeks), and within the organism's lifetime (compare to

adaptation). This may be a discrete occurrence or may

instead represent part of a periodic cycle, such as amammal

shedding heavy winter fur in favor of a lighter summer coat.

Organisms can adjust their morphological, behavioral,

physical, and/or biochemical traits in response to changes in

their environment. While the capacity to acclimate to novel

environments has been well documented in thousands of

species, researchers still know very little about how and why

organisms acclimate the way that they do. When used as a

technical term (such as in the study of physiology),

acclimatization refers to a natural process (e.g., shedding

heavy winter fur with natural seasonal change), whereas the term acclimation is reserved for changes occurring in response to an artificial or controlled situation, such as changes in temperature imposed in an experimental manipulation.