​This two-volume work is a testament to the abiding interest and human fascination with ammonites. We offer a new model to explain the morphogenesis of septa and the shell, we explore their habitats by the content of stable isotopes in their shells, we discuss the origin and later evolution of this important clade, and we deliver hypotheses on its demise. The Ammonoidea produced a great number of species that can be used in biostratigraphy and possibly, this is the macrofossil group, which has been used the most for that purpose. Nevertheless, many aspects of their anatomy, mode of life, development or paleobiogeographic distribution are still poorly known. Themes treated are biostratigraphy, paleoecology, paleoenvironment, paleobiogeography, evolution, phylogeny, and ontogeny. Advances such as an explosion of new information about ammonites, new technologies such as isotopic analysis, tomography and virtual paleontology in general, as well as continuous discovery of new fossil finds have given us the opportunity to present a comprehensive and timely "state of the art" compilation. Moreover, it also points the way for future studies to further enhance our understanding of this endlessly fascinating group of organisms.

It is widely acknowledged that life has adapted to its environment, but the precise mechanism remains unknown since Natural Selection, Descent with Modification and Survival of the Fittest are metaphors that cannot be scientifically tested. In this unique text, invertebrate and vertebrate biologists illuminate the effects of physiologic stress on epigenetic responses in the process of evolutionary adaptation from unicellular organisms to invertebrates and vertebrates, respectively. This book offers a novel perspective on the mechanisms underlying evolution. Capacities for morphologic alterations and epigenetic adaptations subject to environmental stresses are demonstrated in both unicellular and multicellular organisms. Furthermore, the underlying cellular-molecular mechanisms that mediate stress for adaptation will be elucidated wherever possible. These include examples of ‘reverse evolution’ by Professor Guex for Ammonites and for mammals by Professor Torday and Dr. Miller. This provides empiric evidence that the conventional way of thinking about evolution as unidirectional is incorrect, leaving open the possibility that it is determined by cell-cell interactions, not sexual selection and reproductive strategy. Rather, the process of evolution can be productively traced through the conservation of an identifiable set of First Principles of Physiology that began with the unicellular form and have been consistently maintained, as reflected by the return to the unicellular state over the course of the life cycle.

The Mesozoic Era begins with the approximately 50-million-year-long Triassic Period, a major juncture in Earth history when the vast Pangaean supercontinent completed its assembly and began its fragmentation, and the global biota diversified and modern-ized after the end-Permian mass extinction, the most extensive biotic decimation of the Phanerozoic. The temporal ordering of geological and biotic events during Triassic time thus is critical to the interpretation of some unique and pivotal events in Earth his-tory. This temporal ordering is mostly based on the Triassic time-scale, which has been developed and refined for nearly two centu-ries. This book reviews the state of the art of the Triassic timescale and includes comprehensive analyses of Triassic radio-isotopic ages, magnetostratigraphy, isotope-based and cyclostratigraphic correlations and timescale -relevant marine and non-marine bio-stratigraphy.

Some 250 million years ago, the earth suffered the greatest biological crisis in its history. Around 95 percent of all living species died out—a global catastrophe far greater than the dinosaurs' demise 185 million years later. How this happened remains a mystery. But there are many competing theories. Some blame huge volcanic eruptions that covered an area as large as the continental United States; others argue for sudden changes in ocean levels and chemistry, including burps of methane gas; and still others cite the impact of an extraterrestrial object, similar to what caused the dinosaurs' extinction. Extinction is a paleontological mystery story. Here, the world's foremost authority on the subject provides a fascinating overview of the evidence for and against a whole host of hypotheses concerning this cataclysmic event that unfolded at the end of the Permian. After setting the scene, Erwin introduces the suite of possible perpetrators and the types of evidence paleontologists seek. He then unveils the actual evidence--moving from China, where much of the best evidence is found; to a look at extinction in the oceans; to the extraordinary fossil animals of the Karoo Desert of South Africa. Erwin reviews the evidence for each of the hypotheses before presenting his own view of what happened. Although full recovery took tens of millions of years, this most massive of mass extinctions was a powerful creative force, setting the stage for the development of the world as we know it today. In a new preface, Douglas Erwin assesses developments in the field since the book's initial publication.