Can you imagine describing a human as an “often hairy on top, bald on the bottom of walking surfaces, bipedal, eyes forward with binocular vision, opposable thumbs, no wings, no feathers, capable of rational thought, and the capacity to love”? In earlier times, such long, descriptive definitions were employed to separate plants and animals for identification. Can you then imagine the difficulty of combining these descriptions into a coherent grouping of like organisms for further study? Well neither could Carolus Linnaeus. He brought order, in fact a binomial order, to the classification scheme for identifying organisms. It's simple, two words: genus and species. You can create some of your own to describe your friends, such as Homo beautifulus or Homo ignoramus; you choose the names depending on the type of people you hang around with.
After organisms were cleverly classified, relations between and among them became more obvious. Analysis techniques used to establish kinship are presented; several are foolproof. However, that is where the understanding ends. Presently, there is a great amount of scientific discussion regarding whether the world would be better off by classifying organisms into a three-, five-, or six-kingdom model. No one has favored a four-kingdom model. All sides are presented here without editorial slant. You choose.
Excerpted from The Complete Idiot's Guide to Biology © 2004 by Glen E. Moulton, Ed.D.. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.