BIOB 370 1st Edition Lecture 9 Outline of Last Lecture I. Metabolic Heat ProductionII. Heat ConductionIII. Heat ConvectionIV. Radiation of HeatV. Evaporative CoolingOutline of Current Lecture II. Source of Heat/ Types of RegulationA. WB and CBIII.WB/CB Trade-OffsCurrent Lecture* Quiz Wed 11th *Sir Charles Brian Blagden (1748-1820) Biagden’s Law: the freezing point of a solution decreases in direct proportion to the concentration of the solution OH4Source of Heat/Type of Temp. Regulation1. Source2. RegulationSourceEndotherm EctothermHomeo WB (warm blooded)RegulationPolkilo CB (cold blooded)Homeotherm: an animal that DOES regulate its body temperature  Endotherm, slope = 0 Polkilotherm: an animal that DOES NOT regulate its body temperature  Ectotherm, slope = 1 Heterothermy: relax strict thermoregulation when conductions are too extreme- Temporal  Conserves H2O + Energy- Regional  Conserves energy/H2O and protects coreWB/CB Trade Off: Energy Flow = Food Availability1. Change in Conductance and Convection2. Passive Mechanisms3. Active Heat Production + Cons.4. Positive Feedback- Metabolic rate has to go up to regulate body temperatureBMR of Endotherm > BMR of Ectotherm given equal size BMR can be 17x, Depends on Tb-Ta and Body sizeBody Size:s/v  surface to volume ratioSpherical Animals- Not such a stupid assumption- Two ways to lower s/v behaviorally V = 4/3 pi r^3A = 4 pi r^2Harder to thermo-regulate when a small animal Body size limit on Endothermic Homeothermy:1. Activity Patterns2. Increase in metabolic rate to balance heat – Gain/lossa. Food availability3. Geographic Patternsa. Bergmann’s Rulei. Species tend to get larger in colder environments Availability of water is also a Trade-off1. Direct loss of H2O in Homeotherms by evap. cooling2. Indirect effect – GBR increases in Endotherms. High BMR  High respiration rate  Hight resp. H2O loss- This interacts with body size effect so that small size limits being W.B. particularly if H2O is limitedWB/CB: Aquatic EnvironmentHeterothermal Fish – Solving the 02/ Heat capacity problem of water - Most fish are ectothermicHeterothermic Fish – Bluefin Tuna heat exchange by Rete Mirabile- Blood cooled on way out of extremities- Bird regional meteroth allows same mechanism