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Polychaetes are very common marine worms belonging to the Annelid family that are of interest to marine biologists and invertebrate zoologists. The book presents an understanding of the biology of this group with many illustrations.
This book focuses on explaining the distribution of sexual systems (simultaneous hermaphroditism, sequential hermaphroditism, environmental sex determination,dioecy, androdioecy, etc.) among taxa, which remains a major challenge in evolutionary biology. Although significant advances have been made for angiosperms, there is not yet a theory that predicts the sexual system for the majority of animal taxa, and other taxa of plants also remain poorly understood. The problem, particularly for animals, is that sexual systems can be very conservative, with whole phyla and classes being characterized by a single sexual system; for example essentially the whole phylum Platyhelminthes is simultaneously hermaphroditic, whereas the Insecta (Hexapoda) and the Tetrapoda among the vertebrates, are exclusively dioecious. Sex allocation theory on the other hand, suggests that sexual systems should be highly responsive to evolution, changing with population density, life span, patterns of resource availability, etc. The book provides an overview of the topic and then presents a series of chapters, each dealing with a taxon with substantial lability in sexual system in order to identify the factors associated with changes in sexual system in each case. By doing so, the authors reveal factors that have not been considered in formal theory but seem to have a major impact on transitions between sexual systems. This book appeals to a wide readership in fields from zoology and evolutionary biology to botany.
This book offers a comprehensive study of species- and genus-level diversity and chorology of the global freshwater fauna to date. It gives a state of the art assessment of the diversity and distribution of Metazoa in the continental waters of the world.
The fascination of the Annelida to scientists lies in the beauty of their structures and the functionality of their body plan, the tremendous adaptive radiation which has made it possible for these animals to colonize almost all marine, limnic and terrestrial biotopes. In doing so they have evolved a great variety of life forms, and their reproduction and development are correspondingly diverse, with many modes and patterns unique in the animal kingdom. In this special volume recent progress in this broad research area is presented by 26 specialists, in general through surveys or treatments of selected examples. Some of them review important annelid taxa such as the Nereididae, Syllidae, Spionidae, Cirratulidae, Clitellata, and Pogonophora; others analyse reproductive and developmental structures and phenomena in annelids, e.g. segmental organs, sex pheromones, oogenesis, mating systems, sperm types, life cycles, larval settlement, cleavage and symmetry of embryos, or discuss controversial approaches to annelid systematics. The book will be of interest to all zoologists who work with annelids as well as to embryologists and other researchers in reproductive biology.
With its 104 chapters, this Encyclopedia of aquatic ecotoxicology reveals the diversity of issues, problems and challenges that have faced, and are facing today, receiving environments. It also indicates ways by which tools, strategies and future investigations can contribute to correct, minimize, solve and prevent water quality degradation. Structured homogeneously, the chapters convey salient information on historical background, features, characteristics, uses and/or applications of treated topics, often complemented by illustrations and case studies, as well as by conclusions and prospects. This work is most suitable for teaching purposes. Academics, for example, could literally deliver comprehensive lectures to students simply based on chapter outlines and contents. Meet the Authors of the Encyclopedia! Check out 'Meet the Authors' under ADDITIONAL INFORMATION (Right menu).
This is the first and only book, so far, to deal with the causal basis of evolution from an epigenetic view. By revealing the epigenetic "user" of the "genetic toolkit", this book demonstrates the primacy of epigenetic mechanisms and epigenetic information in generating evolutionary novelties. The author convincingly supports his theory with a host of examples from the most varied fields of biology, by emphasizing changes in developmental pathways as the basic source of evolutionary change in metazoans. - Original and thought provoking--a radically new theory that overcomes the present difficulties of the theory of evolution - Is the first and only theory that uses epigenetic mechanisms and principles for explaining evolution of metazoans - Takes an integrative approach and shows a wide range of learning
In this Special Issue, we address the state of the art of the systematics of the main annelid groups and the improvements in the diversity they hold, with special emphasis on the latest discoveries in well-studied areas, expeditions to unsurveyed areas or environments, or the use of novel techniques that allow for the improvement of biodiversity knowledge. We are hoping that this Special Issue will provide a platform facilitating a review of current knowledge on the subject, identifying current research problems, as well as indicating directions and research trends for the future.
Black & white print. Concepts of Biology is designed for the typical introductory biology course for nonmajors, covering standard scope and sequence requirements. The text includes interesting applications and conveys the major themes of biology, with content that is meaningful and easy to understand. The book is designed to demonstrate biology concepts and to promote scientific literacy.