Feature SummaryA number of practical features within the textbook enhance its usefulness for students. It is richly illustrated with figures that include new information and provide fresh perspective. Each chapter opens with an outline. Important concepts and anatomical terms are boldfaced. Cross references direct students to other areas of the text where they can refresh their understanding or clarify an unfamiliar subject. Each chapter concludes with a chapter overview, which draws attention to some of the concepts developed within the chapter. Important literature is cited at the end of each chapter; and a web address connects them to further references and resources. Boxed essays are included in most chapters. Their purpose is to present
subjects or historical events that students should find interesting, and perhaps from time to time, even fun. A glossary of definitions is included at the end of the book,
with four appendices: (A) Vector Algebra, (B) International System of Units, (C) Common Greek and Latin Combining Forms, and (D) Classification of Chordates.
In addition to its practical features, the textbook also uses selected topics within vertebrate morphology, function, and evolution to develop student skills in critical thinking and mastery of concepts within a coherent framework.Critical Thinking
Within the sciences, critical thinking is the ability to marshal factual information into a logical, reasoned argument. Especially if accompanied by a laboratory, a course in vertebrate morphology delivers hands-on experience with the anatomy of representative animals. Students can be directly engaged in the discovery of vertebrate form. But they can be encouraged to go beyond this. Instructors can lead students into larger issues—How does it function? How did it evolve? For example, early on in the textbook, students are introduced to “Tools of the Trade”, the methods by which we empirically examine how parts work
and how we can place organisms within a phylogenetic context. After a discussion of basic morphology, each chapter discusses how these systems work and how they evolved.
I have deliberately included new, neglected, or competing views on function and evolution. Many of these ideas come from Europe, where they have been known for a long time. Personally, I find many of these ideas compelling, even elegant. Others strike me, frankly, as thin and unconvincing. Despite my own skepticism, a few contrary ideas are included (e.g. calcichordate origin of vertebrates). My purpose is to get students to think about
issues of form, function, and evolution.
Several theories on the evolution of jaws are discussed, as are several theories of the origin of paired fins. Often students expect that today we have the final answers. Students implore, “Just tell me the answer.” The debate about dinosaur physiology is a wonderful opportunity to show students the ongoing process of scientific investigation. Most have seen the Hollywood films and expect the issue settled. But we know that science is a process of refinement, challenge, and sometimes revolutionary change. One boxed essay sets forth the early case for dinosaur endothermy. That debate spawned further investigation that now returns to challenge such a view of dinosaurs as “hot-blooded” beasts. The second boxed essay on dinosaur endothermy presents this newer and contrary evidence, and thereby showcases how, even in extinct animals, it is possible to test hypotheses about their physiology, morphology, and lifestyles.Concepts
Vertebrate morphology also helps develop an appreciation and understanding of the scientific concepts that unite biology and reflect on “how” science works. As John A. Moore put it, science is a “way of knowing” (Moore, American Zoologist, 1988). Comparative morphology throws into clear relief differences and similarities between organisms. The concepts of homology, analogy, and homoplasy help us understand the basis of these comparative features. Many of the concepts were birthed in the nineteenth century and have grown into the guiding themes of biology today. Evolution, descent with modification
through time, is one of the foundation concepts in biology. Vertebrate morphology provides a showcase of adaptive change on the basic vertebrate body plan. But evolution is change in a highly integrated organism, a connected system of parts and their functions. This too was
recognized within the nineteenth century, suggesting constraints on evolutionary modification. Vertebrate morphology provides compelling examples of how an integrated
organism might evolve. For example, a remarkable fossil record documents an undeniable change in jaw articulation within synapsids, seeing the two participating bones (articular, quadrate) of basal synapsids replaced by two different bones in derived groups including mammals. Fossil intermediates between the two conditions mark the anatomical changes, but they also suggest how functional changes, which must accompany evolving systems, also
change without disrupting performance.
Within many vertebrate systems, the close coupling of form and function with lifestyle are illustrated. Built on a basic vertebrate plan, the tetrapod locomotor system illustrates the close relationship between limbs and axial skeleton, and the type of locomotion—flight, cursorial, burrowing. The cardiovascular system, especially in organisms that exploit water and air, illustrates the close relationship between vascular morphology and the physiological
flexibility that permits. The basic concepts of form, function, and adaptive evolution parade before us as we move from system to system in vertebrate morphology.
Evolution proceeds most often by remodeling, modification of a basic underlying plan, not by all new construction. This is illustrated in the skeletal system, as well as within the cardiovascular (aortic arches) system. |
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2006 McGraw-Hill Higher Education