Reading Logarithmic

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10

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1 10 100 1000 10000 100000 1000000

time (s)

rocks (No.)

time (s) rocks (No.)15 1

40000 23006500000 105004275000 85000

900 46745 3267 3219 1014 11

654 3262.7 1

175000 950006200 3174

Surface Area to Volume Ratio

Length of r

Inversely proportional to size

SA:V and allometry

Length of r

“Allometric” describes whenthere is a relationship betweenthe size of organisms and any oftheir features.

• This SA:V relationship is allometric.

• So is the relationship between organism weight and SMR.

SA:V and metabolism

Total Metabolism• An elephant uses more O2 than a

mouse, in an hour.

• BUT a gram of mouse uses more O2 than a

gram of elephant in an hour.

Standard Metabolic Rate• Bigger individuals use more O2 than smaller

individuals, per unit time.

• Per gram body weight, smaller animals use more O2 than larger animals.

SA:V and metabolism

Can you describe more than one way in which a lower SA:V affects the metabolism of an animal?

Ectothermy vs Endothermy

Did you know that metabolic rates in mammals = 10x those in reptiles?

Endothermy is expensive!

(not warm or cold blooded)

Metabolism

How do you think ecologists use information on metabolism?

Can you define…

• Respiration:

• Ventilation:

• Metabolism:

• Manometry:

• SMR:

• Endothermic:

• Ectothermic:

Can you define…

• Respiration: Role of O2 in extracting energy from

organic compounds.

• Ventilation: Pumping air into and out of the body.

• Metabolism: Sum total of all chemical processes in

the body.

• Manometry: Method to measure and quantify

metabolic rates.

• SMR: Standard Metabolic Rate (mL O2/g/h).

• Endothermic: Generates heat internally.

• Ectothermic: Obtains heat from external sources.

Can you answer…

How did you estimate metabolic rates in lab?

What is SMR?

What is the difference between total metabolism and SMR?

What is an advantage and a disadvantage of the tracheal system in insects?

Can you answer…

How did you estimate metabolic rates in lab? (You should know this!)

What is SMR? Energy (O2) used per gram body weight in an individual. It is a function of body weight.You can measure through O2…or CO2

What is the difference between total metabolism and SMR?(You should think about this!)

What is an advantage and a disadvantage of the tracheal system in insects?

Did you read about

Tidal flowThe amount of air that passes in and out of the lung during normal respiration.

What is the difference between total lung capacity and tidal volume?

Take Home Message

All of this boils down to what happens at a cellular level.

Recall: When you bring oxygen into your system, you let that oxygen oxidize glucose. This takes energy out of storage and makes it available for ATP synthesis.

Think about this, then think about the insect tracheal system and our own mammalian system again.