Six Animal Phyla (IMAGE) University of Arizona Caption This is a simplified evolutionary tree of six representative animal phyla, illustrating differences in body form, habitat, and species numbers among them. Credit T. Jezkova/Shutterstock/Aaron Ambos/J. Wiens Usage Restrictions This visual may only be used in conjunction of reporting/posting of this news release. Credit must be stated as indicated. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.