Increased emphasis on gene activity, signal transduction and the emphasis on the roles of paracrine factors in development. This undergraduate textbook synthesizes the organismal, cellular, and evolutionary aspects of animal development. The seventh edition adds a chapter on the medical implications of developmental biology. The CD-ROM contains 140 videos and 300 labeled photographs that walk through the life cycle of model organisms. Annotation (c)2003 Book News, Inc., Portland, OR.