Topic 7- Energy Budgets

Question 1

What is an advantage of large animals having a small surface area to volume ratio?

Answer 1

it allows them to lose heat more efficiently, makes temperature regulation easier.

Question 2

What is the relationship between Metabolic Rate and Animal Body Mass?

Answer 2

As body mass increases, metabolic rate increases

Question 3

which has a larger metabolic demand, smaller or larger animals?

Answer 3

Smaller animals have larger metabolic demands

Question 4

what is hyperallometry (positive allometry)?

Answer 4

as one dimension increases, another increases with a greater proportion.

Question 5

what is hypoallometry (negative allometry)?

Answer 5

as one dimension increases, another increases to a lesser proportion.

Question 6

What is Eassimilation?

Answer 6

the energy available to the organism, Ein-Eexcretion.

Question 7

Can Eassimilation be negative?

Answer 7

Yes, if Eassimilation is positive the energy can be used towards Eproduction (growth and reproduction), if Eassimilation is negative more energy is being used than produced.

Question 8

If a cat weighs 20 kg and eats 20% of its body mass in food that gives 200J/g of energy. What is Ein?

Answer 8

Mass x 0.20 x amount of energy from food
=20 000g x 0.20 x 200 J/g
=800 000J
=800 kJ

Question 9

if a 20 kg cat excretes 50g of urea and 200g of feces, the urea is 10J/g of energy and the feces is 250J/g of energy, what is Eexcretion?

Answer 9

grams of urea x energy of urea + grams of feces x energy of feces
=(50g x 10J/g) + (200g x 250J/g)
=50 500 J
=50.5 kJ

Question 10

if you have a 20 kg cat, with an energy input of 800 kJ and an energy output of 50.5kJ, what is Eassimilation? What happens with this value?

Answer 10

Eassimilation= Ein-Eexcretion
= 800- 50.5
=749.5 kJ
This cat would be able to put energy towards growth or reproduction.

Question 11

what is resting metabolic rate?

Answer 11

an organisms metabolic rate at rest, including daily activites

Question 12

what is basal metabolic rate?

Answer 12

metabolic rate at absolute rest, lowest possible metabolic rate

Question 13

what is standard metabolic rate?

Answer 13

metabolic rate at specific temperatures, only used for ectotherms

Question 14

what is metabolic rate used for?

Answer 14

1.helps determine how much food an organism needs
2. gives a quantitative measurement of total activity
3.helps determine pressure on an ecosystems energy supplies

Question 15

what is an ectotherm?

Answer 15

ectotherms rely on external environment for temperature regulation.

Question 16

what is an endotherm?

Answer 16

endotherms regulate their own internal body temperature.

Question 17

which has a higher MR, endotherms or ectotherms of the same size?

Answer 17

endotherms have higher MR than ectotherms because they have to spend large amounts of energy on maintaining their internal temperature.

Question 18

what is the relationship between mass specific metabolic rate and animal mass?

Answer 18

as animal mass increases mass specific metabolic rate decreases. this is due to the surface area to volume ratios.

Question 19

A 20kg cat lives in a house that is 22 degrees celcius during the day (8 hrs) and 16 degrees celcius at night (15 hrs). The cat spends 0.5 J/gh at 22 degrees, and 1 J/gh at 16 degrees. What is the Ermr?

Answer 19

Ermr= (energy spent at 22 x hours at that temp)+(energy spent at 16 x hrs at that temp)
= (0.5J/gh x 8) + (1.0J/gh x 15)
=380 000 J
= 380 kJ

Question 20

What is Eactivity?

Answer 20

Eactivity involves most forms of movement above resting state. When activity increases, heat generated may cover the thermoregulation requirements of a dormant animal.

Question 21

a 20kg cat runs around the house for one hour which uses 10 J/g*h. What is Eactivity?

Answer 21

Eactivity= mass x energy x hours spent
= 20 000g x 10J/g*h x 1hr
=200 000 J
=200 kJ

Question 22

what is Eproduction?

Answer 22

Eproduction is the energy for both reproduction and growth of bio mass.

Question 23

Can Eproduction be negative?

Answer 23

Yes if Eproduction is positive then mass will increase or organism can have children, if Eproduction is negative then the organism will lose mass, called muscle wasting.

Question 24

A 20kg cat has the values Ein= 800kJ Eexcretion=50.5kJ Ermr= 380kJ and Eactivity=200kJ What is Eproduction? What is the cat going to do?

Answer 24

Eproduction= Energyin - All outputs
= 800kJ - (50.0kJ+380kJ+200kJ)
=169.5 kJ
The cat will have energy to put towards biomass or reproduction.