Explore the classification of living things in this online, college-level textbook. Learn about taxonomy and its history through diagrams and descriptive information.

Expand understanding of classification with this tutorial designed to help you learn how living organisms are classified according to their evolutionary history.

In online and offline activities, students broaden their understanding of animals by learning to identify and classify animals into six categories: mammals, birds, fish, amphibians, reptiles, and invertebrates.