27: Introduction to Animal Diversity Last updated Save as PDF Page ID 1816 OpenStax OpenStax 27.0: Introduction 27.1: Features of the Animal Kingdom 27.2: Features Used to Classify Animals 27.3: Animal Phylogeny 27.4: The Evolutionary History of the Animal Kingdom 27.E: Introduction to Animal Diversity (Exercises) Thumbnail: Animal diversity. (CC BY-SA 2.5 / cropped from original; via Wikimedia Commons ).