I wonder if anyone has put together a history of taxonomic schemes; I could not find very much on the Internet.
Here was Aristotle's classification of the animal kingdom:
Blooded animals:
- Viviparous quadrupeds (mammals)
- Birds
- Oviparous quadrupeds (reptiles, amphibians)
- Fish
- Whales and dolphins
Bloodless animals:
- Cephalopods
- Crustaceans
- Insects (true insects, arachnids, myriapods)
- Shelled animals
- Plant-animals (zoophytes) (sea anemones, etc.)
Linnaeus's classification of the animal kingdom was similar in spirit, though explicitly hierarchical and more detailed.
His classification of the plant kingdom, however, was much more artificial -- he classified flowering plants by stamen count. It was convenient for identification if not much else, and later biologists worked out a proper "Linnean" classification of plants.
Linnaeus's system we remember on account of its being biologically "reasonable"; there were several others proposed in past centuries.
I recall from somewhere that 18th cy. naturalist Buffon proposed classifying by usefulness to humanity, with the cow coming the closest to our species.
And in the early 19th cy. a certain Swainson proposed a "quinary" system, which was a hierarchical system that used groups of 5 arranged in circles. This seems almost impossibly forced, and it was strongly criticized by Swainson's contemporaries.
[This message has been edited by lpetrich, 04-20-2003]