Transcript St. Francis Xavier University Third Year Biology Courses

Biology 201
Dr. Edwin DeMont
Chapter 28
Temperature Regulation
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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 high - enzymes will be denatured and reactions
will slow or cease.
Too low - enzymes will also be adversely affected.
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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?
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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.
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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.
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Why care?
November 16, 2007
“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.”
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".
Intergovernmental Panel on Climate Change
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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)
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Fourth Year Biology Courses
401 - Comparative Physiology and Biophysics (DeMont)
403 - Physiology of Sensations (Brackenbury)
417 - Microbial Pathogenics (Graham)
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