Overview Of Last Of The Dinosaurs

Last of the Dinosaurs begins by looking at the geological and ecological conditions that created opportunities for the expansion of dinosaurs of the Early and Late Cretaceous Epochs. Section One encompasses worldwide geologic and climatic changes of the Cretaceous Period. Chapter 1 describes widespread changes to ocean and land environments, including changes to climates worldwide, that served as catalysts for the radiation of dinosaurs and other vertebrates. Temperate global climates allowed dinosaurs to live in every part of their world. The rise of flowering plants was the cause of dramatic turnover in the food supply of these animals and also affected their continued success and survival.

Section Two encompasses the evolution of saurischian dinosaurs of the Cretaceous Period. Chapter 2 describes the continuing evolution of the sauropods and the last of their line. It was during this time that the radiation of these animals shifted to the southern continents and resulted in the appearance of the biggest sauropods of all. Chapter 3 revisits the theropods, exploring several parallel lines of evolution that led, at one end, to the largest land predators of all time and, at the other, to the small predatory dinosaurs that were the ancestors of birds.

The origin of birds is explored in Chapter 4; the chapter introduces the probable roots of their evolution and reveals some of the controversies surrounding the link between dinosaurs and birds. Within this context, the spectacular Early Cretaceous fossil beds of China are introduced; these beds are the source of many specimens of feathered, nonflying dinosaurs and early bird specimens that have greatly aided the study of bird origins.

Section Three encompasses the evolution of ornithischian dinosaurs of the Cretaceous Period, including several groups that appeared for the first time during this span. Chapter 5 introduces the herbivorous ornithopods, whose subgroups include the basal iguanodonts and hadrosaurs, many with astonishingly varied head crests and dental adaptations. Chapter 6 describes two additional clades of widespread and varied plant-eating dinosaurs: the Cera-topsia, or horned dinosaurs, and the Pachycephalosauria, or bone-headed dinosaurs.

Section Four encompasses the nondinosaurian reptiles of the Mesozoic Era. Chapter 7 introduces the flying reptiles known as the Pterosauria, a successful and varied clade of animals representing the first vertebrates to have developed powered flight. Pterosaurs lived in the world of the dinosaurs as masters of the skies. Chapter 8 describes a variety of extinct marine reptiles that dominated the oceans of the Mesozoic. These creatures had a worldwide distribution and included the dolphinlike ichthyosaurs; the walruslike placodonts; long- and short-necked nothosaurs, plesiosaurs, and pliosaurs; the monstrous mosasaurs; extinct marine crocodiles; and the first marine turtles.

The conclusion of Last of the Dinosaurs explores the mass extinction that ended the reign of the non-avian dinosaurs and many other terrestrial and marine creatures of the time, and provides a framework for assessing what might have happened to cause such a catastrophic disappearance of life.

Each chapter uses an abundance of tables, figures, and photos to depict the life, habitats, and changing evolutionary patterns affecting the evolution of the vertebrates. Several chapters also include "Think About It" sidebars that elaborate on interesting issues, people, history, and discoveries related to Mesozoic life.

Last of the Dinosaurs builds on foundational principles of geology, fossils, and the study of life that are introduced in other volumes of this series, The Prehistoric Earth. Readers who would like to refresh their knowledge of certain basic terms and principles in the study of past life may want to consult the glossary in the back of Last of the Dinosaurs. Perhaps most important to keep in mind are the basic rules governing evolution: that the process of evolution is set in motion first by the traits inherited by individuals and then by the interaction of a population of a species with its habitat. Changes that enable the population to survive accumulate generation after generation, often producing and allowing species to adapt to changing conditions in the world around them. As Charles Darwin (18091882) explained, "The small differences distinguishing varieties of the same species steadily tend to increase, till they equal the greater differences between species of the same genus, or even of distinct genera." These are the rules of nature that served to stoke the engine of evolution throughout Earth's history, ultimately giving rise to the myriad forms of life whose descendants still populate Earth.

SECTION ONE: The World of the Dinosaurs

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