Adaptation to a Single Climatic Variable

Adaptive change in response to a single climatic variable is-

Correct Answer: Acclimation

Acclimation is the adaptive physiological change that occurs in response to a single controlled climatic variable (e.g., temperature only, or humidity only), typically in a laboratory setting.

Acclimation vs. Acclimatization

• Acclimation: Response to a single environmental variable → controlled/laboratory conditions. Example: Exposing an animal only to high temperature (30°C → 40°C) and measuring physiological adjustments (increased sweat gland size, changes in cardiovascular response).
• Acclimatization: Response to the complex natural environment with multiple variables changing simultaneously (temperature + humidity + altitude + photoperiod + feed availability). Example: Animals moved from sea level plains to high-altitude Himalayan pastures.

Definitions of Weather and Climate

• Weather: Short-term (day to day) atmospheric conditions of a specific place
• Climate: Long-term average weather pattern of a geographic region

Thermal Neutral Zone (TNZ)

• Range of environmental temperatures where the animal maintains body temperature with minimal energy expenditure
• Below lower critical temperature → shivering thermogenesis
• Above upper critical temperature → increased heat dissipation (sweating, panting)