I WANT TO BE A FIELD BIOLOGIST, WHY DO I NEED TO TAKE: PHYSICS? CHEMISTRY? ECONOMICS?

1. I WANT TO BE A FIELD BIOLOGIST, WHY DO I NEED TO TAKE: PHYSICS? CHEMISTRY? ECONOMICS?

2. WHY DO I NEED TO TAKE: PHYSICS? CHEMISTRY? ECONOMICS? These fields interface with each other in a field known as biophysical ecology. This is the study of how organisms interact with the physical environment. Your text suggests this is simply the study of heat and water balance in organisms, but it can also include issues such as obtaining food, digesting food, determining what temperatures are best for digestive enzymes, and also understanding the trade-offs organisms must make to survive.

3. HOW MUCH OF THIS WORK GOES ON AT ISU?

4. HOW MUCH OF THIS WORK GOES ON AT ISU? We are one of the top centers in the county for this work. 1. George Bakken (How do organisms maintain temps) 2. Mike Angilletta (Life history ecology vs Biophys eco) 3. Mike Sears (Life history ecology vs Biophys eco) 4. Charlie Amlaner (Telemetry, Sleep, Physiology) 5. Diana Hews (Behavioral Endocrinology+Comm) 6. Steve Lima (Antipredator Behavior vs Biophys eco) 7. Bill Mitchell (Energy and Species Richness) 8. John Whitaker (Natural History) 9. Rusty Gonser (Herp Reproduction/Genetics) 10. Elaina Tuttle (Pop Genetics/Behavior) 11. Peter Scott (Pollination Biology) 12. Dale Sparks (Wildlife Management) 13. Marion Jackson (Forest Ecology) 14. Mary Ann McClean (Microbial Ecology)

5. HOW DO HERPS THERMOREGULATE?

6. HOW DO HERPS THERMOREGULATE? Most animals are active only over a very narrow range of INTERNAL temperatures? WHY? HOW?

7. WHY?? Endurance Sprint Speed Selected Body Temps Metabolized Intake Fig 2 From: Angilletta et al., 2002, J. Therm Biol, 27:203

8. HOW? Fig 6-11

9. AW CRAP AN EQUATION! Heat Energy=  Absorption of Solar Radiation  Metabolic Heat Production  Infrared Radiative Exchange  Convective Heat Exchange  Evaporative Cooling  Conduction

10. Obtaining Energy From: Visible Light Radiation Near Infrared (Always Positive) Heat Energy= Absorption of Solar Radiation  Metabolic Heat Production  Infrared Radiative Exchange  Convective Heat Exchange  Evaporative Cooling  Conduction Fig 6-13 Influenced By: Intensity of Radiation Surface Area of Animal View Factor How Much Is Absorbed

11. Do Snakes Shiver? Heat Energy= Absorption of Solar Radiation  Metabolic Heat Production  Infrared Radiative Exchange  Convective Heat Exchange  Evaporative Cooling  Conduction Fig 6-14 Does This Make Herps Endothermic?

12. Is This Skillet Ready to Cook? Heat Energy= Absorption of Solar Radiation  Metabolic Heat Production  Infrared Radiative Exchange  Convective Heat Exchange  Evaporative Cooling  Conduction Every object warmer than 0K radiates heat into infrared

13. If You Went Streaking Today You Would? A. Get Cold B. Get Busted C. Be Referred to AA D. All the Above Heat Energy= Absorption of Solar Radiation  Metabolic Heat Production  Infrared Radiative Exchange  Convective Heat Exchange  Evaporative Cooling  Conduction Energy Exchange Between Critter and Fluid Media (Air or Water) Around It. Influenced By: Temp Difference Surface Area Velocity of Media Size of Animal

14. Do Herps Sweat? Technically No, But... Heat Energy= Absorption of Solar Radiation  Metabolic Heat Production  Infrared Radiative Exchange  Convective Heat Exchange  Evaporative Cooling  Conduction Reptiles Gape Amphibians Have Porous Skins

15. Heat Energy= Absorption of Solar Radiation  Metabolic Heat Production  Infrared Radiative Exchange  Convective Heat Exchange  Evaporative Cooling  Conduction Why Do We Use Road Cruising as a Census Method?

16. OK, This Stuff is Complicated, Do We Have to Measure All This? Heat Energy= Absorption of Solar Radiation  Metabolic Heat Production  Infrared Radiative Exchange  Convective Heat Exchange  Evaporative Cooling  Conduction USE OPERATIVE TEMPERATURE MODELS--GSB

17. How Good Are These Animals At Maintaining Body Temp? Heliotherms Make Use Of Microhabitats Maintain Very Precise Body Temperatures Thermal Conformers Body Temperatures Fluctuate Widely

18. How Do Herps Survive Winter?

19. Freeze Resistance: Supercooling (antifreeze--Often Glucose, or Glycerol in Blood) Tolerate Freezing: Allow Some Freezing (Supercool The Rest)

20. WATER BALANCE--ANIMAL IN A STEADY STATE Water Drank/Absorbed + Preformed Water + Metabolic Water = Evaporation + Urine + Feces + Salt Glands

21. WATER BALANCE--ANIMAL IN A STEADY STATE Water Drank/Absorbed + Preformed Water + Metabolic Water = Evaporation + Urine + Feces + Salt Glands Which is more important to Amphibians? Reptiles? Sources: Osmosis, Dew Droplets, Drinking, Anuran Pelvic Patch

22. WATER BALANCE--ANIMAL IN A STEADY STATE Water Drank/Absorbed + Preformed Water + Metabolic Water = Evaporation + Urine + Feces + Salt Glands What percentage of your body is water?

23. WATER BALANCE--ANIMAL IN A STEADY STATE Water Drank/Absorbed + Preformed Water + Metabolic Water = Evaporation + Urine + Feces + Salt Glands C6H12O6 + O2 CO2 +H2O + Energy

24. WATER BALANCE--ANIMAL IN A STEADY STATE Water Drank/Absorbed + Preformed Water + Metabolic Water = Evaporation + Urine + Feces + Salt Glands Is this more of an issue for amphibians or reptiles? How do you limit the amount of water lost this way?

25. WATER BALANCE--ANIMAL IN A STEADY STATE Water Drank/Absorbed + Preformed Water + Metabolic Water = Evaporation + Urine + Feces + Salt Glands How do herps remove nitrogenous waste? Ammonia and Gills Urea--Role in Osmoregulation Uric Acid--The White Stuff Fig 6-9 What do the Inuit use to store water?

26. WATER BALANCE--ANIMAL IN A STEADY STATE Water Drank/Absorbed + Preformed Water + Metabolic Water = Evaporation + Urine + Feces + Salt Glands If you are shipwrecked, do you drink salt water? Why or Why Not?

27. WATER BALANCE--ANIMAL IN A STEADY STATE Water Drank/Absorbed + Preformed Water + Metabolic Water = Evaporation + Urine + Feces + Salt Glands Fig 6-7 Found in Many Reptilian Groups

28. How Do Amphibians Obtain Oxygen? Across the Skin Gills Lungs Which is most important?

29. How Do Amphibians Obtain Oxygen? Across the Skin (Including Bucal Region) Gills Lungs Which is most important?

30. Comparison Amphibian and Reptile Respiration Amphibians obtain most of their oxygen via either cutaneous respiration or gills, lungs are filled via bucal pumping. Squamates obtain oxygen primarily from their lungs, which are filled via negative pressure. Turtles use the organs to create a vacuum in the lungs. When is this a problem? Exceptions: Sea Snakes, Cloacal Respiration, Pharyngeal Respiration

31. How is this oxygen moved to the body?

32. How is this oxygen moved to the body?

33. How does circulation differ between herps and people? Pulmonary/Cutaneous Circulation of Amphibians Nucleated Blood Cells 3 Chambers Ability to Mix or Separate Blood Cardiac Shunt

34. WHY SHUNT BLOOD? 1. Stabilize the oxygen content of blood (Most herps have apneic periods) 2. Right to Left shunt increases heating capacity 3. Right to Left Shunt also removes lungs from circuit when the animal is holding its breath. REMEMBER: These animals are highly evolved for their lifestyles.