miscellaneous slide











Surface Area-to-Volume Ratio

by Greg Crowther


Surface area to volume ratio:
If you're small, then it's high;
If you're large, it's low.

Animals arenít cube-shaped, but letís pretend.
Say L is the length of a side -- what then?
6L to the 2 over L to the 3 equals SA over V.
SA over V.


Animalsí internal metabolic activities canít
Exceed what they exchange with the environment.
And so, as they get wide and tall,
Their metabolic rates must fall.
Metabolic rates must fall.



Written for BIOL 220 at the University of Washington, this song explains the relationship between body size and mass-specific metabolic rate. It references the formulas for the surface area and volume of a cube with sides of length L. In the line "If you're large, it's low," the alliteration of "large" and "low" facilitates recall that a large body size implies a low surface area-to-volume ratio.

MP3 (demo)

score (with melody play-back)