Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Compare structural and organization characteristics of Porifera and Cnidaria
Describe the progressive development of tissues and their relevance to animal complexity
Identify the two general body forms found in the Cnidaria
Describe the identifying features of the major cnidarian classes

As part of the Invertebrates exhibit at the National Zoo, this site highlights various facts and interesting information on Cnidarians. Topics covered in the overview include Habitat, Getting Physical, One Way Street, and Simple Plan.