1. Biology 201 Dr. Edwin DeMont St. Francis Xavier University Chapter 28 Temperature Regulation

2. St. Francis Xavier University Thermoregulation Every animal’s physiological functions are linked to temperature. The temperature range for an organism has shaped its enzyme evolution so that the optimum temperature reflects that temperature at which its enzymes are fully functional (i.e., its metabolism operates most efficiently at this temperature range). Too low - enzymes will also be adversely affected. Too high - enzymes will be denatured and reactions will slow or cease.

3. St. Francis Xavier University Thermoregulation Homeostasis involves all body systems; thermoregulation is a homeostatic mechanism to minimize internal temperature changes in the face of external temperature variation. Thermoregulation involves a number of organ systems, including the nervous and circulatory systems. How do animals cope with temperature fluctuations?

4. St. Francis Xavier University Ectotherms Ectotherms (sometimes referred to as poikilotherms) derive their body heat from the environment—they have a low metabolic rate and poor insulation, so they change sites to increase or decrease heat (seek basking areas or shaded areas). These animals tend to be more common in the tropics, as life there requires less energy expenditure.

5. St. Francis Xavier University Endotherms Endotherms derive their heat from metabolic processes. They may have an insulating layer of fat in the hypodermis of the skin. Fur and feathers also provide insulation. Endothermic animals can colonize a wide range of habitats.

6. St. Francis Xavier University Why care? Intergovernmental Panel on Climate Change “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.” November 16, 2007 Oslo, 12 Oct 07 - The Intergovernmental Panel on Climate Change and Albert Arnold (Al) Gore Jr. were awarded the Nobel Peace Prize "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change".

7. St. Francis Xavier University Third Year Biology Courses 301 - Form and Function in Animals (DeMont) 302 - Evolution (Garbary) 303 - Human Biomechanics (DeMont) 304 - Vertebrate Physiology (Brackenbury) 306 - Ichthyology (Mitchell) 312 - Marine Biology (Buckland-Nicks) 315 - Introductory Microbiology (Graham) 335 - Developmental Biology (Buckland-Nicks) 343 - Comparative Anatomy of Vertebrates (Lauff)

8. St. Francis Xavier University Fourth Year Biology Courses 401 - Comparative Physiology and Biophysics (DeMont) 403 - Physiology of Sensations (Brackenbury) 417 - Microbial Pathogenics (Graham)