Use visuals to encourage collaboration.

This text begins the study of life by focusing on the definitive characteristics of life. A general under- standing of chemistry, cell biology, and tissues rounds out Unit 1: Introduction to the Study of Life. Unit 2: Movement through the Environment discusses the hu- man systems involved in movement: the skeletal, mus- cular, and nervous systems. Unit 3: Protection from the Environment describes how the integmentary and lym- phatic systems protect the body against injury and inva- sion by pathogens. Unit 4: Thriving within the Environ- ment describes how the cardiovascular and respiratory systems transport nutrients and oxygen to the tissues, and how food is digested and wastes are eliminated. Unit 5: Populating the Environment covers the action of the endocrine system, which brings us to sexual ma- turity and the reproductive system. Fertilization and de- velopment complete this unit. Finally, Unit 6: Adapting to and Affecting the Environment relates this informa- tion to inheritance and DNA, human evolution, and the ecological balance of the biosphere, which serve to tie the entire book together. viii Preface ix isualizing Human Biology immerses stu- dents in the world around them by demonstrating the interaction between humans and the environment, while fo- cusing on the human organism. Both structures and functions of the human body are covered in an engag- ing, personable style, following the natural curiosity of students. Topics such as evolution, ecology, and chem- istr y are introduced in a nonthreatening and logical fashion. Designed for introductory courses in human biology, the book answers authentic student questions in each chapter. Intriguing photographs, many from the National Geographic Society’s collection, sprinkled throughout the book remind the student that human biology is actually a study of humans in the world. Top- ics that regularly appear in the media are introduced and explained in the context of human biology. ORGANIZATION Any course in human biology must introduce the stu- dent to science through a focus on human beings; the authors achieve this by stressing the role of the human in the environment. This theme cements the broad- ranging information in human biology courses to- gether, providing an organizing principle that simulta- neously relates human biology to the student’s daily experience. P R E FAC E V Organized by this theme of “humans in the en- vironment,” the chapters are filled with stimulating im- ages and photographs that create natural breaks in the information, allowing the reader to set and achieve at- tainable study goals. Each chapter begins with an en- gaging vignette designed to stimulate a desire for more information. The chapters are grouped in larger, cohe- sive units that ensure the logical flow of information in the entire course.