Temperature Regulation in Cold Environments

Temperature Regulation in Cold Environments PowerPoint PPT Presentation


  • 352 Views
  • Uploaded on
  • Presentation posted in: General

Hibernation. Takes place during the winter in response to cold environmentsAnimal lowers body temperature a significant amountBody temperature remains at lowered level for several days at a timeSome animals store energy as body fat to survive hibernation period, others store food. Hibernation (Co

Download Presentation

Temperature Regulation in Cold Environments

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


1. Temperature Regulation in Cold Environments Option 1 – Controlled Hypothermia (Dormancy or Torpor) Hibernation Winter Sleep Daily Torpor

2. Hibernation Takes place during the winter in response to cold environments Animal lowers body temperature a significant amount Body temperature remains at lowered level for several days at a time Some animals store energy as body fat to survive hibernation period, others store food

3. Hibernation (Continued) Hibernating mammals do not remain at low body temperature for entire winter Animals wake up periodically. Those that store food do eat food during periods of wakefulness. Smaller mammals have longer periods at low body temperature Males typically enter hibernation earlier than females and terminate hibernation earlier than females

4. Winter Sleep Occurs in some Carnivora Bears, raccoons, badgers Body temperature is only decreased by 5 to 6 C Because these animals are able to store large amounts of body fat they can maintain higher metabolic rates during the winter and live off of the body fat stores

5. Daily Torpor There is a significant decrease in body temperature for part of one day The decrease in Tb takes place during the normal sleep time of the animal Daily torpor may occur on consecutive days Decrease in Tb is not as great as in hibernators; usually to about 15 C

6. Thermoregulation in Cold Environments (2) Body Size and Metabolism Bergmann’s Rule – races of mammals from colder climates tend to be larger than races of the same species from warmer climates Surface to Volume ratios Body mass may change seasonally Consequences of long thin shape

7. Thermoregulation in Cold Environments (3) Insulation Changes Increases in thickness of the fur Increases in thickness of subcutaneous fat layer An increase in insulation decreases the Lower Critical Temperature The Upper Critical Temperature may also be lowered Arctic fox has a LCT of –40C in winter; decreased need for food in a cold environment

8. Insulation in Different Mammals

9. Insulation Acclimation

10. Thermoregulation in Cold Environments (4) Appendages Allen’s Rule – Appendages of mammals in colder environments are shorter than those of animals of same species found in warmer climates See Figure 8.10 of textbook

11. Appendages (Continued) Regional Heterothermy and Countercurrent heat exchange Found in nose, legs, tails, ears, flipper of marine mammals

12. Regional Heterothermy

13. Countercurrent Heat Exchange

14. Thermoregulation in Cold Environments (5) Coloration Gloger’s rule – Races in warm and humid areas are more heavily pigmented than those in cool and dry areas Color change in some mammals White coloration in many arctic mammals; a thermal advantage?

15. Thermoregulation in Cold Environments (6) Modification of Microclimates Nest building Huddling behavior Both conserve body heat by increasing insulation

16. Thermoregulation in Cold Environments (7) An Increase in Thermogenic Capacity Nonshivering Thermogenesis Brown Fat Stimulated by Norepinephrine Thermogenin Protein Involved

17. Increase in Thermogenic Capacity

  • Login