I don't understand this mneumonic device

Relating to biology, what does this phrase stand for?

"Kings play chess on fine grain sand."

Kingdom phylum class order family genus species.

Look 'em up.

"Kings play chess on fine grain sand."
King - K = Kingdom
Play - P = Phylum
Chess - C = Class
On - O = Order
Fine - F = Family
Grain - G = Genus
Sand - S = Species

It's the taxonomic ranking system.
http://en.wikipedia.org/wiki/Taxonomic_r…