The Sixth Edition ofBIOLOGY by Neil Campbell and Jane Reece builds upon the earlier versions' dual goals to both help readers develop a conceptual appreciation of life within the context of integrating themes, and to inspire readers to develop more positive and realistic impressions of science as a human activity. The authors have thoroughly updated each of the book's eight units to reflect the existing progress in our understanding of life at its many levels, from molecules to ecosystems. Examples of updated content include the Human Genome Project, the revolution in systematics, HIV as a research model in evolutionary biology, the role of cell-signaling pathways in plant responses, new frontiers in neurobiology, and experimental approaches that are advancing ecology. To assure accurate representation of each field of biology, a team of stellar specialists has worked with the authors in updating every unit. An innovative design breakthrough ensures that the art is as current as the content. Guided Tour diagrams explicitly guide readers through the more challenging figures, succinctly explaining key structures, functions, and steps of processes within the figure, reducing the need to look back and forth between legend and art. It's as if an instructor were looking over the reader's shoulder and clarifying each part of a figure! Guided Tour commentary is set in blue, making it easy to differentiate these explanations from ordinary labels and keeping the figure itself clear and uncluttered. For college instructors and students.