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

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.