Natural Order

Did you ever wonder how this muddle of 'scientific' terms was selected to identify the natural order of living things:

kingdom

phylum

class

order

family

genus

species

The only word that looks at all essentially scientific is "phylum." Oh, maybe also "genus." Okay, also species, if we're going to loosen the term "species" enough to ignore its various nonscientific meanings.

Anyway, how were these chosen? Anybody know?