Vertebrate Biology, Third Edition

The First Edition of Vertebrate Biology was published in 1998; the Second Edition in 2012.  Since that time, many taxonomic changes and revisions have occurred, many new paleontological discoveries have enabled us to better comprehend the evolutionary origins of vertebrates, and many new discoveries have been made concerning the anatomy, physiology, and life histories of individual species of vertebrates – all of which have been incorporated into the Third Edition. But even more important are the global and regional changes that are affecting entire ecosystems and the very survivability of entire vertebrate species.  As I pondered the effects of the changes that have come to the forefront over the past two decades, I decided that the final two chapters of the Second Edition – Chapter 15. Extinction and Extirpation and Chapter 16. Conservation and Management – had to be expanded.  Thus, I made the decision to expand and elaborate on these subjects.  The resulting final chapters in the Third Edition are now entitled:  (16) Extinction and Extirpation: Natural and Human-Caused; (17) Restoration of Endangered Species; (18) Regulatory Legislation Affecting Vertebrates; (19) Wildlife in a Modern World:  Threats and Conservation; (20) Climate Change; and (21) Wildlife Management in a Modern World.  My hope is that the many users of this text will become better informed not only about systematics, anatomy, physiology, movements, population dynamics, and intra- and interspecific interactions of vertebrates,  but that they will also become more knowledgeable about the many environmental factors affecting vertebrates, both locally, regionally, and on a worldwide basis, and that they will be stimulated to take action to reduce and/or reverse the problems caused by humans that are affecting many vertebrate species, including ourselves.

Extinction is the total disappearance of a species.  More than 99 percent of all plant and animal species that have ever lived are extinct.  Dinosaurs, passenger pigeons, heath hens, dodos, mastodons, and saber-toothed tigers are among the many vertebrates that have become extinct.  Natural extinction, a normal ongoing process with a certain number of species steadily disappearing over time, is somewhat balanced by the natural process of speciation. Occasionally, mass extinctions caused by volcanic action, meteors, and other events, have occurred on a worldwide basis and have led to the disappearance of a large number of species, and even larger taxonomic groups, within a relatively short period of geologic time.  However, many scientists now believe that humans have increased the pace of extinction far beyond natural levels, so that species are now becoming extinct at rates 1,000 to 10,000 times the natural rate that occurred before our ancestors first appeared on Earth.  Raven (1995) predicted that plant and animal species will likely become extinct at the rate of 50,000 species a year during the next few decades.

A chapter is devoted to specific legislation (the Endangered Species Act in the United States, for example, and many others) that has been enacted by many countries to help a wide variety of species – either directly or indirectly by preserving their rapidly-disappearing habitat, protecting flyways, protecting vital breeding areas, etc.  Protected areas such as national parks, wildlife sanctuaries and refuges, biosphere reserves, and world heritage sites have afforded protection for many species.  While these measures have proven effective in some cases, much more needs to be done.  In some cases, critical legislation is being weakened and is putting threatened species at risk.  Habitat fragmentation, the destruction of forests – both temperate and tropical, the effects of cell towers, wind turbines, highways, the draining of wetlands, air and water pollution, endocrine disruptors, noise pollution, and mountaintop removal coal mining are major factors that affect biodiversity.  Border wall construction along the Texas-New Mexico-Arizona border is fragmenting habitat and disrupting the natural migration routes of many vertebrates. 

Finally, I have devoted an entire chapter to a topic of even more overwhelming significance – climate change.  I felt that topics such as global warming, greenhouse gases, melting of glaciers, rising sea levels, desertification, the northward migration of plants and animals, and the effects of global warming on plant blooming and migratory species warranted special consideration.  Climate change is wreaking havoc in many ways with an increasing number of hurricanes, floods, and wildfires so drastic and extensive that they have never been seen before.  Many protected areas are already seeing the effects of climate change in a variety of ways.

The next generation of vertebrate biologists has its work cut out for them.  Time is short if life as we know it will continue.  In some small way, I hope that the material I have presented in Vertebrate Biology, Third Edition will enlighten, encourage, and stimulate such efforts.

Order Vertebrate Biology: Systematics, Taxonomy, Natural History, and Conservation, Third Edition – published on August 4, 2020 – at the following link:

Donald W. Linzey is a faculty member in the Department of Fish and Wildlife Conservation at Virginia Tech. He is the author of Vertebrate Biology: Systematics, Taxonomy, Natural History, and Conservation, Third Edition. Among his numerous books are The Mammals of Virginia; Mammals of Great Smoky Mountains National Park; A Natural History Guide to Great Smoky Mountains National Park; Snakes of Virginia; and Snakes of Alabama.