Metabolic Rate & Allometric Scaling

Question 1

Ingested chemical energy

Answer 1

energy contained in chemical bonds of food animals ingest

Question 2

Fecal chemical energy

Answer 2

Energy contained in chemical bonds of undigested compounds

Question 3

Absorbed chemical energy:

Answer 3

Energy contained in chemical bonds of materials that are absorbed from intestine to blood stream

Question 4

Heat

Answer 4

All living animals generate heat

Question 5

Biosynthesis

Answer 5

making of proteins and lipids (use of absorbed chemical energy)

Question 6

Maintenance

Answer 6

circulation and tissue repair (use of absorbed chemical energy)

Question 7

Internal work

Answer 7

Movement of inner body stuff

Question 8

External work

Answer 8

Movement of limbs

Question 9

Metabolic rate

Answer 9

Rate at which an animal converts absorbed chemical energy to heat. Heat production per unit time

Question 10

Direct calorimetry/ Direct calorimeter

Answer 10

o Measuring the rate at which an animal produces heat

o 1 calorie/sec = 4.186 joules/sec = 1 watt

Question 11

Indirect calorimetry

Answer 11

Measuring metabolism through physiological and chemical associations

Question 12

Respirometry

Answer 12

Because of the consistent relationship between O2, CO2, and heat produced, you can calculate metabolic rate by simply measuring O2 consumption of CO2 production

Question 13

Mass Balance

Answer 13

Chemical Energy Input = Chemical energy output. Way to measure indirect calorimetry

Question 14

Respiratory exchange ratio

Answer 14

o Moles of CO2 Produced * time-1/Moles of O2 Consumed * time-1

Question 15

Specific dynamic action

Answer 15

Following consumption of a meal, metabolic rate briefly increases over basal levels

Question 16

Basal metabolic rate

Answer 16

o Homeotherms within thermoneutral zone
o Fasting
o Resting (lying down, but awake)

Question 17

Standard metabolic rate

Answer 17

o Polikilotherms at any specific body temp (SMR at Tb=25 c)
o Fasting
o Resting

Question 18

Metabolic scaling

Answer 18

Study of the relationship between metabolic rate and body mass

Question 19

Weight – specific metabolic rate

Answer 19

M/W = aW(b-1) Metabolic rate/unit body mass

Question 20

Allometric equation

Answer 20

Log(M)=Log(aWb) makes equation linear. Advantageous for expression the allometric relationship in the linear form

Question 21

Rubner’s surface law

Answer 21

o BMR is proportionate to a mammal’s surface area
o Reasoning
• Mammals maintain 37C Tb, tend to lose heat to environment
• Rate of heat loss proportionate to surface area of mammal
• Smaller mammals have more surface area per unit weight, and therefore faster hear loss
• Head loss must be replace metabolically to maintain Tb

Question 22

Fractal geometry

Answer 22

o Internal transport of O2 and nutrients via circulatory system necessary for metabolism to occur.
o Branching nature of this system imposes constraints on delivery as you scale up and down
o Because of these constraints, smaller animals more efficient at delivering resources throughout the body hence higher mass-specific metabolic rates.
o Fractal theory predicts a metabolic rate scaling exponent of b=0.75