More than two thirds of all living organisms described to date belong to the phylum Arthropoda. But their diversity, as measured in terms of species number, is also accompanied by an amazing disparity in terms of body form, developmental processes, and adaptations to every inhabitable place on Earth, from the deepest marine abysses to the earth surface and the air. The Arthropoda also include one of the most fashionable and extensively studied of all model organisms, the fruit-fly, whose name is not only linked forever to Mendelian and population genetics, but has more recently come back to centre stage as one of the most important and more extensively investigated models in developmental genetics. This approach has completely changed our appreciation of some of the most characteristic traits of arthropods as are the origin and evolution of segments, their regional and individual specialization, and the origin and evolution of the appendages. At approximately the same time as developmental genetics was eventually turning into the major agent in the birth of evolutionary developmental biology (evo-devo), molecular phylogenetics was challenging the traditional views on arthropod phylogeny, including the relationships among the four major groups: insects, crustaceans, myriapods, and chelicerates. In the meantime, palaeontology was revealing an amazing number of extinct forms that on the one side have contributed to a radical revisitation of arthropod phylogeny, but on the other have provided evidence of a previously unexpected disparity of arthropod and arthropod-like forms that often challenge a clear-cut delimitation of the phylum.

This book provides a comprehensive discussion on plant responses in hyperarid regions of Egypt, China, Mexico, and Pakistan. It describes their location, physiographic features, accidental vegetation along two transects, endangered vegetation species, human impact, and variety of plant types (e.g. climbing, succulent, and parasitic). Studies on biotic and abiotic interactions, plant biodiversity, and soil-plant relationships are also covered. Covering a wide range of plant conditions and adaptations, this book analyzes what happens when plants must endure very high temperatures and aridity. Plants have adapted by evolving their physical structure to store and conserve water. Examples are the absence of leaves which reduces transpiration and the growth of extremely long roots, allowing them to acquire moisture at, or near the water table. Plants in hyperarid habitats have also made behavioral adaptations in order to survive by synchronizing with the seasons of greatest moisture and/or coolest temperatures. For example, desert perennials remain dormant during dry periods of the year, then spring to life when water becomes available. The book includes many color illustrations, and has extensive and up-to-date references for further reading.

Knowledge of the basic mechanisms of human disease is essential for any student or professional engaged in drug research and development. Functional gene analysis (genomics), protein analysis (proteomics), and other molecular biological techniques have made it possible to understand these cellular processes, opening up exciting opportunities for no