| Cold Hardiness in Amphibians and Reptiles |
| How do poikilotherms deal with extremely cold temperatures? |
| Slide 2 |
| Metabolism |
| Endothermy | ||
| Ectothermy | ||
| Ectothermic Heat Balance |
| Ectothermic Heat Balance |
| Typical Modes of Heat Balance | ||
| Ectothermic Heat Balance |
| Examples of thermal regulation | ||
| Ectothermic Heat Balance |
| Examples of thermal regulation | ||
| This brings us to the title of our talk |
| How do poikilotherms deal with extremely cold temperatures? |
| Over-wintering amphibians and reptiles |
| Over-wintering amphibians and reptiles |
| Over-wintering amphibians and reptiles |
| Related to strategy 1 |
| Slide 13 |
| Slide 14 |
| Over-wintering amphibians and reptiles |
| Slide 16 |
| Over-wintering amphibians and reptiles |
| Over-wintering amphibians and reptiles |
| Slide 19 |
| Òcold hardinessÓ in extreme cold |
| Freeze toleranceÉthe ability af an organism to freeze solid and survive the processes of freezing and thawing | |
| Organs are encased in ice, circulation and respiration cease, muscle movement stops. 65% of the animal is frozen solid. The eye turns white or blue due to the freezing of the lens. How animals survive this every winter is yet unknown, yet it happens | |
| HOW CAN THIS BE? |
| Freeze tolerance |
| Several mechanisms at work: |
| Freeze tolerance |
| Òcold hardinessÓ in extreme cold |
| SupercoolingÉthe ability af an organism (or liquids within the organism) to exist at sub-freezing temperatures without freezing. | |
| HOW CAN THIS BE? |
| Supercooling |
| Two citeria need to be met in order for a liquid to freeze | |
| ¥ the liquid needs to be at or below the equilibrium freezing point | |
| ¥ presence of a nucleating agent, or catalyst to provide a location for ice crystals to develop |
| Supercooling |
| Painted turtles are unlike other turtles ecologically |
| Painted turtles |
| Painted turtles |
| Painted turtles |
| Painted turtles |
| Conclusion |