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 symptoms, potential causes, and treatment of several examples of nervous system disorders

Conflicting theories about what causes autism are explored in this video segment from 'Greater Boston.' Scientists still don't have an answer, and while many focus on genetics, some suspect that the environment may also play a role. Mark Blaxill, whose daughter Michaela is autistic, explains why he thinks the disorder is triggered by environmental factors. Dr. Martha Herbert, who studies the brains of autistic children, says that toxins like metals, pesticides, and PCBs have all come under suspicion. But other scientists, like Dr. David Miller, say the key to autism lies in a person's genes. Includes background essay and discussion questions. [3:31]