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