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This volume addresses the question of the speciation of modern Homo Sapiens. The subject raises profound questions about the nature of the species, our defining characteristic (it is suggested it is language), and the brain changes and their genetic basis that make us distinct. The British Academy and the Academy of Medical Sciences have brought together experts from palaeontology, archaeology, linguistics, psychology, genetics and evolutionary theory to present evidence and theories of our understanding of these issues. Palaeontological and genetic work suggests that the transition from a precursor hominid species to modern man took place between 100,000 and 150,000 years ago. Some chapters discuss what is most characteristic of the species, focussing on language and its possible basis in brain lateralization. This work is placed in the context of speciation theory, which has remained a subject of considerable debate since the evolutionary synthesis of Mendelian genetics and Darwinian theory. The timing of specific transitions in hominid evolution is discussed, as also is the question of the neural basis of language. Other chapters address the possible genetic nature of the transition, with reference to changes on the X and Y chromosomes that may account for sex differences in lateralization and verbal ability. These differences are discussed in terms of the theory of sexual selection, and with reference to the mechanisms of speciation.

Animal phylogeny is currently undergoing a major revolution due to the availability of an exponentially increasing amount of molecular data and the application of novel methods of phylogenetic reconstruction, as well as the many spectacular advances in palaeontology and molecular developmental biology. Traditional views of the relationships among major phyla have been shaken up and new, often unexpected, relationships are now being considered. At the same time, the emerging discipline of evolutionary developmental biology, or evo-devo, has offered new insights into the origin and evolvability of major traits of animal architecture and life cycle. All these developments call for a revised interpretation of the pathways along which animal structure and development has evolved since the origin of the Metazoa. This book takes on this challenge, successfully integrating morphological, fossil, and molecular evidence to produce a novel reinterpretation of animal evolution. Central to the book's approach is an evo-devo perspective on animal evolution (with all the fresh insights this has given into the origin of animal organization and life cycles), complementary to the more traditional perspectives of pattern (cladistics, comparative anatomy, and embryology), mechanisms (developmental biology), and adaptation (evolutionary biology). The book advocates the need to approach the study of animal evolution with a critical attitude towards many key concepts of comparative morphology and developmental biology. Particular attention in the book is paid to the evolution of life cycles and larval forms.

The extent to which human activity has influenced species extinctions during the recent prehistoric past remains controversial due to other factors such as climatic fluctuations and a general lack of data. However, the Holocene (the geological interval spanning the last 11,500 years from the end of the last glaciation) has witnessed massive levels of extinctions that have continued into the modern historical era, but in a context of only relatively minor climatic fluctuations. This makes a detailed consideration of these extinctions a useful system for investigating the impacts of human activity over time. This book describes and analyses the range of global extinction events which have occurred during this key time period, as well as their relationship to both earlier and ongoing species losses. By integrating information from fields as diverse as zoology, ecology, palaeontology, archaeology, and geography, and by incorporating data from a broad range of taxonomic groups and ecosystems, this text provides a fascinating insight into human impacts on global extinction rates, both past and present.

How can we bring together the study of genes, embryos, and fossils? This is a critical synthesis of the study of individual development in fossils. It brings together an up-to-date review of concepts from comparative anatomy, ecology, and developmental genetics, and examples of different kinds of animals from diverse geological epochs and geographic areas. Can fossil embryos demonstrate evolutionary changes in reproductive modes? How have changes in ocean chemistry in the past affected the development of marine organisms? What can the microstructure of fossil bone and teeth reveal about maturation time, longevity, and changes in growth phases? This book addresses these and other issues, and documents with numerous examples and illustrations how fossils provide evidence not only of adult anatomy, but also of the life history of individuals at different growth stages. The central topic of biology today—the transformations occurring during the life of an organism and the mechanisms behind them—is addressed in an integrative manner for extinct animals.