Lecture 3 Notes on Animal Size and Physiology PDF
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This document provides lecture notes on animal size and physiology. The content covers topics such as physiological allometry, basal metabolic rate (BMR), and various animal groups—invertebrates, mammals, and birds. The notes include illustrative figures and graphs.
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Lecture 3: 10 Jan. Size matters: body size, allometry and physiology physiological allometry causes, exceptions, correlates, implications Reading: 19-20, 184-192, 230-233 1 1 Scope of Animal Size How big...
Lecture 3: 10 Jan. Size matters: body size, allometry and physiology physiological allometry causes, exceptions, correlates, implications Reading: 19-20, 184-192, 230-233 1 1 Scope of Animal Size How big? How small? 2 2 Scope of Invertebrate Size How small? How big? 3 3 Scope of Mammal Size How big? How small? 4 4 Scope of Bird Size How small? How big? 5 5 Patterns of Size Change: Isometry proportions remain same with change in size 6 6 Patterns of Size Change: Anatomical Isometry proportions remain same with change in size 7 7 Patterns of Size Change: Anatomical Allometry Allos (gr.) = different proportions change with size 8 8 Physiological Allometry: Linear Axis Scales Basal Metabolic Rate (BMR) M = aWb eq. 7.3 a: proportionality constant b: mass exponent BMR = M 7.7 9 9 Log Axis Scales & Allometry: BMR How to make M=aWb a straight line? log M=log a + b log W log a: intercept b: slope log BMR=log70 + 0.72logM BMR = 70M0.72 10 10 Mass-Specific Allometry: BMR/g 7.7 M = aWb BMR = 70M0.72 mass exponent (b) M/W = aW(b-1) BMR/g = 70W-.28 7.8 11 11 Log Scales & Mass-Specific MR log M=log a + b log W log BMR=log 70 + 0.72 log M slope of line? 7.10a 12 12 What “Causes” Metabolic Allometry? heat produced within animal volume, exchanged with env. over SA? small animals lose heat more rapidly over their larger SA’s (relative to V) and need higher metabolism to compensate why doesn’t this explanation always work? 1. should be same relationship as SA/V, i.e… measured b usually… 2. ectotherm (i.e. thermoconformers) metabolism also scales at ~ 0.75, and heat loss… 13 13 Ectotherm Scaling 14 14 Scaling of Maximal Metabolic Rate (VO2 max): b=0.86 Elephant. sig.>0.72 (BMR) 15 15 Measuring VO2 max 16 16 Measuring VO2 max Cooperative * Semi-lucid university O2 and CO2 analyzers elephant professors 17 17 Measuring VO2 max O2, CO2 meters air 18 18 scaling constraints often require novel Informative adaptations Exceptions mammal heart mass scaling: isometric mammal heart rate scaling: (mass exp. -0.25) Pygmy shrew: based on mass would predict really small heart that beats at ~3000 beats/min BUT Physiological constraint cardiac muscle cannot contract faster than 1,400 beats/min evolutionary “solution”? Pygmy Shrew: 2.5 g 19 19 Mammalian Cardiac Scaling Matching heart function to metabolic rate Heart rate = 241 M-0.25 Pygmy Shrew: Predicted from mass Heart mass = 0.0059 M0.98 Actual 20 20 Informative Exceptions animals “off the line?” e.g. pronghorn; from these data describe what’s different about the pronghorn? 9.10 Pronghorn (Antilocapra americana) 21 21 Informative Exceptions Allometry of components of aerobic metabolism in mammals most similar to VO2max why except?? lung: sig. higher mass exponent than VO2max why don’t lungs scale with aerobic capacity? what else do lungs do? 22 22
