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:

Describe the various types of body plans that occur in animals
Describe limits on animal size and shape
Relate bioenergetics to body size, levels of activity, and the environment

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

Explain the differences in animal body plans that support basic animal classification
Compare and contrast the embryonic development of protostomes and deuterostomes

The five-part symmetry of echinoderms is demonstrated, as the five-armed starfish is morphed into an urchin that is then morphed into a sea cucumber. [1:42]

Leo Q. Wan takes us into the human body to show how biological asymmetry can be quite beautiful. [4:18]