437lect29 energysizetemp 2006 -...

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Lecture 29, 30 Nov 2006

Vertebrate PhysiologyECOL 437 (MCB/VetSci 437)

Univ. of Arizona, Fall 2006

Kevin Bonine & Kevin Oh

http://eebweb.arizona.edu/eeb_course_websites.htm

Allometry

Metabolism (Ch5)

Thermal Physiology (Ch8-9)

Geocheloneelephantopus

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Housekeeping, 30 Nov 2006

Upcoming Readings

today: Text, Ch. 5, 8-9 (Allometry, Metabolism, Temperature)

Tues 05 Dec: Ch4 (Nutrition, Feeding, Digestion)=last day of lecture

Wed 06 Dec: Student Oral Presentations

Tues 12 Dec: Final Exam

Thanks to Kevin and Dana

- Term paper and previous drafts.- Oral presentations in lab, ppt file, handout.

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Allometry:

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5(Eckert 16-7)

Mouse-to-Elephant Curve

4g shrew eats 2g/day

elephant is 1 million x larger

Allometry

6(Hill et al. 5.6)

1 week of food

x 6

x 0.3

Allometry

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(Eckert 16-8)

MR = aMbb = 0.75(slope)logMR = loga + b(logM)

Allometry

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Scaling

Power Functions:

How do morphology and metabolism change with body mass?

MR = aMb

Metabolicrate

Y-intercept (of log-log plot)

Body mass

Scaling exponent

logMR = loga + b(logM)

Can look at mass-specific rates by dividing through by M

Take log of both sides

(Linearizes)

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Allometry

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Knut Schmidt_Nielsen 1972

b = 1.13(slope)

logMskeleton = loga + b(logM)

Isometryis rare

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(Eckert 16-20)

CO

ST

Locomotor Mode

Allometry

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Scaling Effects

Allometry - changes in body proportions as animalsget larger (mouse vs. elephant)

Metabolic Rate - mass-specific metabolic ratedecreases with increasing body mass

(16-6)

linear

squared

cubed

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Knut Schmidt_Nielsen 1972

(a) = elephant freaked out and died (1960’s) in a study of ‘musth’ [elephantine fallacy]

-What is the correct dose?

-Importance of Scaling!

0.1mg/kg

0.2mg for 70 kg

Allometry

14Knut Schmidt_Nielsen 1972

Hemoglobin dissociation curves and body sizeAllometry

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15Knut Schmidt_Nielsen 1972

Bohr effect and body sizeAllometry

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Capillary density and body sizebat

rat

Allometry

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Metabolism

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World Class Human Runners

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Metabolism

-Chemical reactions in the body-Temperature-dependent rates-Not 100% efficient, energy lost as heat

(not ‘lost’ if used to maintain Tb)

1. Anabolic-creation, assembly, repair, growth

(positive nitrogen balance)

2. Catabolic-energy release from complex molecules

(carbos, fats, proteins)-energy storage in phosphate bonds (ATP) and

metabolic intermediates (glucose, lactate)

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Chemical Energy

(Eckert 16-1)

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21Hill et al. 2004, Fig 4.9

10% Rule

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Energy Available for:- Growth, Maintenance, Reproduction

- SDA (specific dynamic action)

(Hill et al. 5.5)

Metabolism

No free lunch!

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Male emperor penguin >100days w/o food when incubating eggs

Knut Schmidt_Nielsen 1997

Metabolism and Ecology

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K vs. r selected(logistic curve)

-Larger animals invest proportionally less in reproduction

-Sperm is cheap

-Direct and indirect costs

Metabolism and Ecology

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25Fig. 5-5

Duellman and Trueb, 1986

Fig. 17-13Stebbins and Cohen, 1995

Fetal teeth in caecilians

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Metabolic Rate

-measurable conversion of chemical energy into heat

-used to understand:-energy budgets-dietary needs-body size implications-habitat effects-costs of various activities-mode of locomotion-cost of reproduction

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Much more difficult for water breathing animals to maintain body temperatures above ambient because rate of heat transfer is greater than rate of O2 transferin water (high specific heat)

Amblyrhynchus cristatus

Knut Schmidt_Nielsen 1997

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Fish Example:

-Differences in vascular organization

-Tuna with warm, aerobic musclemedially

-Countercurrentblood flow (don’t lose heat to cold water across gills)

(17-19)

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29Knut Schmidt_Nielsen 1997

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Metabolic Rates

-Basal Metabolic Rate, BMR-minimal environmental and physiological stress(appropriate ambient temperature,

post-digestive, resting etc.)

-Standard Metabolic Rate, SMR-similar to BMR, but at a given Tb

-Field Metabolic Rate, FMR-average metabolic rate of animal in natural setting-hard to measure

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Knut Schmidt_Nielsen 1997Knut Schmidt_Nielsen 1997

birds

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Metabolic Rates

Basal Metabolic Rate, BMR-important components:

1. Membrane form and functionmaintenance of electrochemical gradients-proton pumps in mitochondrial membranes-Na/K-ATPase pumps in plasma membrane

2. Protein synthesis

3. ATP formation

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Metabolic heat production(chemical energy ‘lost’ as heat during metabolism)

Pough et al., 2001

-Endotherms-surface area to volume ratio -Larger ectotherms can be heterothermic

- leatherback (Dermochelys coriacea)- pythons (female brooding clutch)- tuna and increased core temperature

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Thermal Neutral Zone

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Thermal Neutral Zone

(Eckert 17-21)

Within TNZ:-Vasomotor-Posture-Insulation

fluff fur/feathers

Critical TemperatureLower Upper

Below TNZ:-Increase metabolism

above basal

Above TNZ:-Cool via evaporation