L2 - Animal Energetics 2

Question 1

What does BMR stand for and what is its definition?

Answer 1

BMR: Basal Metabolic Rate

The metabolic rate of a:

• resting
• post absorptive
• adult
• animal in its thermo-neutral range

Question 2

What is the problem with the definition of BMR?

Answer 2

Thermo-neutral range only applies to endotherms, insects and reptiles don’t have this

Question 3

Define SMR

Answer 3

Standard Metabolic Rate

the MR of an adult animal at rest, that is post absorptive, at a GIVEN BODY TEMPERATURE

Question 4

Define RMR

Answer 4

Resting Metabolic Rate

the MR of an adult animal at rest at an unknown absorptive state

Question 5

Define FMR

Answer 5

Field Metabolic Rate

The rate of energy expenditure by a free living animal

Question 6

Define ADMR

Answer 6

Average Daily Metabolic Rate over 24h regardless of activity levels

Question 7

What is the problem with FMR?

Answer 7

No time specified

e.g.: difference between day and night is large

Question 8

What are the 3 lab techniques of measuring metabolism?

Answer 8

1. Direct Calorimetry
2. Indirect Calorimetry - measurement from food intake and excretion
3. Indirect Calorimetry - Respirometry

Question 9

What is direct Calorimetry?

Answer 9

Direct Calorimetry is a direct measure of heat production, whereas indirect Calorimetry is a measure of O2 consumption and CO2 production.

Direct calorimetry is usually performed using a bomb calorimeter, where food is burned in a sealed container and the amount of heat produced is then converted into the number of calories that the food contains

Question 10

A guinea pig melts 1kg of icw with 17kJ of energy. If it took 45minutes to melt 1.25kg of ice, what is the metabolic rate of the guinea pig?

Answer 10

17 x 1.25 = 21.3kJ
60 x 45 = 2700
21.3/2700 = 7.87Js-1

Question 11

Give 2 cons of measure metabolism via food intake and excretion

Answer 11

It can’t be done in growing animals

Technically cumbersome –> making sure all excretion is collected etc.

Question 12

What is Respirometry?

Answer 12

Measures the amount of O2 used in oxidative processes.

It can be used in the field

Question 13

Give 2 problems with Respirometry

Answer 13

1. It doesn’t take into account anaerobic respiration
2. It can be used in the wold but care must be take to not use it in direct sunlight as the glass/plastic boxes that are used will create heat

Question 14

What does each stand for in the equation:

VO2 = Vi x FiO2 - Ve x FeO2

Answer 14

VO2 - rate of use of oxygen
Vi - rate of air flow in
FiO2 - [O2] going in
Ve - rate o air flow out
FeO2 - [O2] out

Question 15

What is the RQ and what does it tell you?

Answer 15

RQ = respiratory quotient = VCO2/VO2 = how much CO2 is made per O2 unit

it is the ratio between CO2 and O2

Question 16

Why do different fuel substances have different RQs?

Answer 16

the number of carbons

Question 17

Give 2 benefits of fat as a fuel store

Answer 17

1. It is very energy dense - only around 5% water, unlike protein and carbohydrates which are 70% and 80%
2. It can act as insulation

Question 18

Why might marsupials of a similar size the their Eutherian counter part have a lower MR?

Answer 18

Body temperature