1. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 1 Energetics & Performance: Components of Heat Exchange Work in Concert

2. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 2 Behavioral Aspects of Thermoregulation –A large part of thermoregulation in amphibians and reptiles is behaviorally controlled –Body temperature generally regulated within a narrow, optimum range of temperatures. Particularly true of reptiles. Temperature sensitive region of brain is the hypothalamus (monitors temperature of blood). Cardiovascular Control of Thermoregulation –In many reptiles, the cardiovascular system is also important in regulating the rate of heating and cooling of the body. Heating and cooling rates are not equal. Why? 3 ways the cardiovascular system helps regulate these rates: –Higher heart rate during heating. –Intracardiac shunt: Blood transfer in heart that increases proportion of blood going to skin and body (decrease amount going to lungs). –Vasodilatation in areas of skin that are warm. Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation

3. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 3 Development of Our Understanding of Thermoregulation: Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation However, Skeptics found that:

4. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 4 Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation Australian Bearded Dragon (Poona barbate) This Lead to Research Into Physiological Adaptation:

5. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 5 Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation And Research Into Behavioral Mechanisms: Dipsosaurus dorsalis Upper “Set Point” Lower “Set Point” Ameiva festiva

6. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 6 Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation As Well As Behavioral Physiology: Brooding female python Non-brooding female

7. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 7 Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation More Behavioral Physiology:

8. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 8 Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation Then Completely Integrated Field Observational Studies:

9. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 9 Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation Similar Effects Exist for Water Balance: Water Effects Water Impacts Temperature Effects

10. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 10 Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation So What Does This Do For Reptiles & Amphibians? Theoretical Real (Ameiva festiva)

11. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 11 Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation Which Came First? Evolution of “Preferred” Body Temperature, or Convergence of Optimal Levels of Processes? Natrix maura

12. Herpetology (Bio 488), Spring ‘11, Poe & Snell, L03 – Energetics & Performance continued 12 Energetics & Performance: Physics of Heat Exchange & Behavior Yield Thermoregulation Either Way the Use of Exothermal Energy Partially Explains the Superiority of Reptiles and Amphibians!