Gaining Ground, Second Edition
The Origin and Evolution of Tetrapods
Publication Year: 2012
Around 370 million years ago, a distant relative of a modern lungfish began a most extraordinary adventure—emerging from the water and laying claim to the land. Over the next 70 million years, this tentative beachhead had developed into a worldwide colonization by ever-increasing varieties of four-limbed creatures known as tetrapods, the ancestors of all vertebrate life on land. This new edition of Jennifer A. Clack's groundbreaking book tells the complex story of their emergence and evolution. Beginning with their closest relatives, the lobe-fin fishes such as lungfishes and coelacanths, Clack defines what a tetrapod is, describes their anatomy, and explains how they are related to other vertebrates. She looks at the Devonian environment in which they evolved, describes the known and newly discovered species, and explores the order and timing of anatomical changes that occurred during the fish-to-tetrapod transition.
Published by: Indiana University Press
Series: Life of the Past
Preface to the Second Edition
Since the first edition of Gaining Ground was completed, much has happened in the field of early tetrapod paleontology and in the wider world that has affected not only the ideas and conclusions presented in the first edition, but also...
This work essentially represents a summary of my research career in early tetrapod paleontology. Throughout this period, I have worked with, been guided and helped by, learned from, and been supported morally and financially by a large number...
List of Abbreviations
1 Introduction: The Origin and Evolution of Tetrapods
Approximately 380 million years ago, something strange and significant happened on Earth. That time is part of an interval of Earth’s history called the Devonian period by scientists such as geologists and paleontologists, but in more popular...
2 Skulls and Skeletons in Transition
This chapter is an introduction to the skeletal anatomy of animals that exemplify the fish–tetrapod transition. The first part examines how the skulls and skeletons of lobe-finned fishes and tetrapods were built, and will introduce the terminology used for the bones. Unfortunately, many of the terms will be...
3 Relationships and Relatives: The Lobe-Fin Family
This chapter introduces the tetrapods’ closest relatives, explains how tetrapods fit into the scheme of relationships with other lobe-fins, and explores how ideas about the ancestry of tetrapods have evolved with changing perspectives. There are a few characteristics of lobe-fins that distinguish them as a group, but the most conspicuous is the eponymous lobed fin, described more fully in Chapters 1 and...
4 Setting the Scene: The Devonian World
The Devonian period opened onto a world far different from the present day. In the earliest stages, over 400 million years ago, even the oxygen content of the air was different from today. According to some models, at the beginning of the Devonian, the air contained about half the present levels of oxygen...
5 The First Feet: Tetrapods of the Famennian
By the latter part of the Late Devonian, the Famennian, vertebrates with indisputable limbs bearing digits—tetrapods—had appeared. Some remarkably well-preserved material from several localities provides details of their anatomy...
6 From Fins to Feet: Transformation and Transition
Chapter 2 looked at opposite ends of a spectrum. At one end was the
structure of a fish such as
7 Emerging into the Carboniferous: The First Phase
At the end of the Devonian, a major extinction event hit most groups of vertebrates, both marine and nonmarine. Although an earlier extinction event at the Frasnian–Famennian boundary has been recognized for many years, it appears to have affected invertebrates, especially marine ones, with most vertebrate...
8 East Kirkton and the Roots of the Modern Family Tree
A small former mining town called Bathgate, about 20 miles from Edinburgh, Scotland, has recently been made famous in the paleontological world for being the location of a window through which to view an extraordinary episode in evolutionary...
9 The Late Carboniferous: Expanding Horizons
During the Late Carboniferous, the continents, which had slowly moved southward through the Devonian and Early Carboniferous, changed direction and began to rotate. Gondwana and Euramerica gradually collided, initiating the formation of the supercontinent Pangaea. The world’s vegetation had...
10 Gaining Ground: The Evolution of Terrestriality
This extended survey of the anatomy and lifestyles of tetrapods throughout the Paleozoic has explored the evidence and speculation bearing on the advent of tetrapods onto land. This final chapter now goes on to consider the evolution..