Linnaeus's Animal Taxonomy

In the tenth edition of systeminature, linnaeus divided the animal world into mammalia, or mammals. Warm blooded animals whose hearts had two atria and two ventricles were mammals if they gave birth to live young; birds if they lay eggs. Cold bloode animalswhose hearts had one atrium and one ventricle were amphibians if they breathed through lungs,. fish if they breede through gills. The latin word mamma, or breast, is the root of the word mammal. To day's scientific taxonomy has more categories at every level and more precise methods for determining what goes where than linnaeus original work did.