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I WANT TO BE A FIELD BIOLOGIST,
WHY DO I NEED TO TAKE: PHYSICS?
CHEMISTRY?ECONOMICS?
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 suggeststhis 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.
HOW MUCH OF THIS WORK GOES ON AT ISU?
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)
HOW DO HERPS THERMOREGULATE?
HOW DO HERPS THERMOREGULATE?
Most animals are active only over a very narrow range of INTERNAL temperatures?
WHY?HOW?
Fig 2 From: Angilletta et al., 2002, J. Therm Biol, 27:203
WHY??
Sprint SpeedEndurance
Metabolized Intake
SelectedBody Temps
HOW?
Fig 6-11
AW CRAP AN EQUATION!
Heat Energy=
Absorption of Solar Radiation
Metabolic Heat Production
Infrared Radiative Exchange
Convective Heat Exchange
Evaporative Cooling
Conduction
Heat Energy=
Absorption of Solar Radiation
Metabolic Heat Production
Infrared Radiative Exchange
Convective Heat Exchange
Evaporative Cooling
Conduction
Obtaining Energy From:Visible Light Radiation
Near Infrared(Always Positive)
Influenced By:Intensity of Radiation
Surface Area of AnimalView Factor
How Much Is Absorbed
Fig 6-13
Heat Energy=
Absorption of Solar Radiation
Metabolic Heat Production
Infrared Radiative Exchange
Convective Heat Exchange
Evaporative Cooling
Conduction
Do Snakes Shiver?
Fig 6-14
Does This Make Herps Endothermic?
Heat Energy=
Absorption of Solar Radiation
Metabolic Heat Production
Infrared Radiative Exchange
Convective Heat Exchange
Evaporative Cooling
Conduction
Is This Skillet Ready to Cook?
Every object warmer than 0Kradiates heat into infrared
Heat Energy=
Absorption of Solar Radiation
Metabolic Heat Production
Infrared Radiative Exchange
Convective Heat Exchange
Evaporative Cooling
Conduction
If You Went Streaking Today You Would?A. Get ColdB. Get BustedC. Be Referred to AAD. All the Above
Energy Exchange Between Critter and Fluid Media (Air or Water) Around It.
Influenced By:Temp Difference
Surface AreaVelocity of Media
Size of Animal
Heat Energy=
Absorption of Solar Radiation
Metabolic Heat Production
Infrared Radiative Exchange
Convective Heat Exchange
Evaporative Cooling
Conduction
Do Herps Sweat?Technically No, But...
Reptiles GapeAmphibians Have Porous Skins
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?
Heat Energy=
Absorption of Solar Radiation
Metabolic Heat Production
Infrared Radiative Exchange
Convective Heat Exchange
Evaporative Cooling
Conduction
OK, This Stuff is Complicated, Do We Have to Measure All This?
USE OPERATIVE TEMPERATURE MODELS--GSB
How Good Are These Animals At Maintaining Body Temp?
Heliotherms
Make Use Of MicrohabitatsMaintain Very Precise Body Temperatures
Thermal Conformers
Body Temperatures Fluctuate Widely
How Do Herps Survive Winter?
Freeze Resistance:
Supercooling (antifreeze--Often Glucose, or Glycerol in Blood)
Tolerate Freezing: Allow Some Freezing (Supercool The Rest)
WATER BALANCE--ANIMAL IN A STEADY STATE
Water Drank/Absorbed + Preformed Water + Metabolic Water
=
Evaporation + Urine + Feces + Salt Glands
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
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?
WATER BALANCE--ANIMAL IN A STEADY STATE
Water Drank/Absorbed + Preformed Water + Metabolic Water
=
Evaporation + Urine + Feces + Salt Glands
C6H12O6 + O2 CO2 +H2O + Energy
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?
What do the Inuit use to store water?
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 GillsUrea--Role in Osmoregulation
Uric Acid--The White StuffFig 6-9
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?
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
How Do Amphibians Obtain Oxygen?
Across the Skin
Gills
Lungs
Which is most important?
How Do Amphibians Obtain Oxygen?
Across the Skin (Including Bucal Region)
Gills
Lungs
Which is most important?
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
How is this oxygen moved to the body?
How is this oxygen moved to the body?
How does circulation differ between herps and people?
Pulmonary/Cutaneous Circulation of AmphibiansNucleated Blood Cells
3 ChambersAbility to Mix or Separate Blood
Cardiac Shunt
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.