Biology of Humans: Concepts, Applications, and Issues 6th Edition

Book Preface

HUMANS ARE CURIOUS BY NATURE. This book was written to stimulate that curiosity, inspiring appreciation for the intricacy of human biology and the place of humans in the biosphere. To satisfy that curiosity with solid and current information, we provide students with a conceptual framework for understanding how their bodies work and for dealing with issues relevant to human health in the modern world. We sustain the student’s interest by continually illustrating the connections between biological concepts and issues of current social, ethical, and environmental concern.

Our central belief is that the application of biological concepts to familiar experiences is the key to helping students see the excitement of science and understand its importance in their lives.

This edition builds on the Fifth Edition’s strengths of clarity, liveliness, consistency, currency, and relevance. The writing is engaging, the explanations straightforward, and the pedagogical framework meticulously constructed. All features are designed to help students identify important facts and ideas, understand them, and appreciate why they matter.

Application of the material to students’ interests brings concepts to life and illustrates the ethical and social relevance of human biology. This strategy is especially apparent in the “Special Topic” chapters and the dozens of Special Interest Essays distributed throughout the other chapters.

Practical Goals and Special Features
The principal goals of this textbook are (1) to give a clear presentation of the fundamental concepts of human anatomy, physiology, development, genetics, evolution, and ecology; (2) to apply these concepts in ways that will both interest and benefit students; (3) to help students develop reasoning skills so they can make use of their newly acquired knowledge in the situations they face in daily life; (4) to help students evaluate the many sources of information available to them and to select those that are reliable and accurate; and (5) to give students an understanding of how the choices they make can affect society and the planet, as well as their own quality of life.

Much of the material covered in human biology has a bearing on ethical, social, and environmental issues that are important to us all. Connections between human biology topics and ethical, social, and environmental issues help students develop a global perspective on their impact on the biosphere and will prepare them to be responsible citizens of their country and the world. Society is currently immersed in many pressing biological debates, and students need the tools to understand these issues and make informed decisions.

New to This Edition

The Sixth Edition includes new features and information that increase application of the material to students’ everyday lives and make it more accessible as well as help them build twentyfirst century skills.
■ A new Consider This Case feature at the end of every chapter presents a scenario relating to the chapter content, followed by critical thinking questions that ask students to apply what they’ve learned in the chapter.
■ A new Finding and Evaluating Information feature at the end of each main chapter presents new research highlighted in current media, and asks students to evaluate the information and conclusions presented, as well as to find other reliable sources of information on the topic.
■ A new Special Topic chapter, titled The Obesity Epidemic, has been added. Focusing on the problem of obesity, this chapter covers topics such as (1) health risks associated with obesity; (2) regulation of food intake; and (3) weight management.
■ Expanded Did You Know? boxes now open every chapter,link directly to the chapter opening photo, and pique students’ interest with fascinating and little-known facts about the topic that follows.
■ A new, inviting design makes the Sixth Edition more student-friendly, easier to read, and reflective of the course level. The new design also helps facilitate an integrated reading experience by using step numbers in complex process figures to connect the text and art.
■ The MasteringBiology online homework, tutorial, and assessment system replaces the Human Biology Place companion website of previous editions. Each end-of-chapter review includes a reminder that directs students to MasteringBiology to access related quizzes, activities, and more.
■ New to this edition are online Dynamic Study Modules, which help students study effectively on their own by continuously assessing their activity and performance in real time.

Special Topic Chapters
The text contains 10 Special Topic chapters: Chapter 1a, Becoming a Patient: A Major Decision; Chapter 8a, Drugs and the Mind; Chapter 10a, Diabetes Mellitus; Chapter 12a, Cardiovascular Disease; Chapter 13a, Infectious Disease; Chapter 15a, The Obesity Epidemic; Chapter 17a, Sexually Transmitted Diseases and AIDS; Chapter 18a, Autism Spectrum Disorder; Chapter 19a, Stem Cells—A Repair Kit for the Body; and Chapter 21a, Cancer. Created to further motivate students to learn, each of these short chapters builds on the “pure biology” presented in the immediately preceding chapter to cover issues likely to be of personal interest. The discussions these chapters contain are more thoroughly developed than would be possible in a boxed essay. Even if instructors do not include these special topics in their reading assignments, we believe the issues are so pertinent to students that they will read the Special Topic chapters of their own volition, or at least refer to them occasionally as guides to a healthier lifestyle.

Much of the information offered in the text is practical: What can be done to prevent the spread of sexually transmitted diseases? How can one take steps to prevent or treat obesity? The body each of us is born with is a most intricate machine, but it does not come equipped with an owner’s manual. In a sense, this book can be the students’ owner’s manual. Studying and applying the lessons to their individual lifestyles and health issues can help students live longer, happier, and more productive lives.

Special Interest Essays
Three categories of Special Interest Essays use the basic scientific content of the chapters to explore issues having broader impact on individual health, society, and the environment. Environmental Issue essays deal with ways in which human activities alter the environment or, conversely (sometimes simultaneously), ways in which the environment influences human health. Among the topics discussed in Environmental Issue essays are asbestos, genetically modified foods, and noise pollution.
Ethical Issue essays explore ethical and social issues related to the topics in a chapter. They explore questions concerning such subjects as anabolic steroid use, gene testing, and the use of nonhuman primates in research.
Finally, Health Issue essays deal primarily with personal health topics. They provide current information on certain health problems that students, their families, or their friends might encounter. Topics discussed in Health Issue essays include acne, osteoporosis, treatments for the common cold, and disparities in health and health care.
All of these essays include Questions to Consider, which ask students to think about the ethical implications of certain behaviors (such as taking anabolic steroids) or medical procedures (such as generating extra embryos as part of infertility treatments).
Stop and Think Questions
The Stop and Think questions scattered throughout each chapter are intended to promote active learning. They invite students to pause in their reading to think about the information that was just presented and apply it to a new and interesting situation. These periodic checks allow students to determine whether they have followed and understood the basic chapter content. In the Sixth Edition we have increased the number of Stop and Think questions in each of the main chapters and added these questions to the Special Topic chapters.

What Would You Do? Questions

The What Would You Do? questions, which are also placed throughout each chapter, challenge the student to form an opinion or to take a stand on a particular issue that society faces today, as well as to identify the criteria used in reaching that opinion or decision. These questions help students see the relevance of biology to real-life problems and foster the practice of thinking through such complicated issues as the use of spermsorting technology by parents to select the gender of their offspring and strategies for slowing the growth of human populations. When the subject of one of these questions is controversial, the text presents examples of arguments from both sides, as well as evidence in support of competing arguments

Brief Contents
1 Humans in the World of Biology 1
1a SPECIAL TOPIC: Becoming a Patient: A Major
Decision 14
2 Chemistry Comes to Life 21
3 The Cell 43
4 Body Organization and Homeostasis 65
5 The Skeletal System 86
6 The Muscular System 101
7 Neurons: The Matter of the Mind 115
8 The Nervous System 127
8a SPECIAL TOPIC: Drugs and the Mind 143
9 Sensory Systems 151
10 The Endocrine System 171
10a SPECIAL TOPIC: Diabetes Mellitus 190
The Organization of the Body
Control and Coordination of the Body
Maintenance of the Body
Reproduction and Development
Genes and DNA
Evolution and Ecology
11 Blood 198
12 The Cardiovascular and Lymphatic Systems 213
12a SPECIAL TOPIC: Cardiovascular Disease 232
13 Body Defense Mechanisms 239
13a SPECIAL TOPIC: Infectious Disease 259
14 The Respiratory System 268
15 The Digestive System and Nutrition 286
15a SPECIAL TOPIC: The Obesity Epidemic 312
16 The Urinary System 317
17 Reproductive Systems 336
17a SPECIAL TOPIC: Sexually Transmitted Diseases
and AIDS 356
18 Development throughout Life 366
18a SPECIAL TOPIC: Autism Spectrum
Disorder 387
19 Chromosomes and Cell Division 394
19a SPECIAL TOPIC: Stem Cells—A Repair Kit
for the Body 412
20 Genetics and Human Inheritance 419
21 DNA and Biotechnology 436
21a SPECIAL TOPIC: Cancer 458
22 Evolution and Our Heritage 470
23 Ecology, the Environment, and Us 491
24 Human Population, Limited Resources,
and Pollution 508