Recently, new genes and their proteins that revealed striking new insights into the early evolution of multicellular animals have been identified and characterized from members of the lowest metazoan phylum, the porifera (sponges). The unexpected result was that the sequences obtained from sponge displayed high similarity to those found in higher metazoa; in consequence, it was concluded that during the transition from protozoa to metazoa the major structural and regulatory proteins evolved only once. The data gathered are now powerful arguments to establish monophyly of metazoa; in addition, new insights on the evolutionary diversification of metazoa were obtained.

Paleontologist Simon Conway Morris provides a guided tour of the world's richest treasure trove of fossils--a fantastically rich deposit of bizarre and bewildering Cambrain fossils, located in Western Canada. 4 plates. 90 linecuts.

The evolution of animal diversity is strongly affected by the origin of novel cell and tissue types and their interactions with each other. Understanding the evolution of cell types will shed light on the evolution of novel structures, and in turn highlight how animals diversified. Several cell types may also have been lost as animals simplified – for example did sponges have nerves and lose them? This book reveals the interplay between gains and losses and provides readers with a better grasp of the evolutionary history of cell types. In addition, the book illustrates how new cell types allow a better understanding permitting the discrimination between convergence and homology.

Tackling one of the most difficult and delicate of the evolutionary questions, this challenging book summarizes the more recent results in phylogenetics and developmental biology that address the evolution of key innovations in metazoans. Divided into three sections, the first considers the phylogenetic issues involving this area of the tree of lif

The interplay between Geology and Biology has shaped the Earth from the early Precambrian, 4 billion years ago. Moving beyond the borders of the classical core disciplines, Geobiology strives to identify chains of cause-and-effect and synergisms between the geo- and the biospheres that have been driving the evolution of life in modern and ancient environments. Combining modern methods, geobiological information can be extracted not only from visible remains of organisms, but also from organic molecules, rock fabrics, minerals, isotopes and other tracers. An understanding of these processes and their signatures reveals enormous applied potentials with respect to issues of environment protection, public health, energy and resource management. The Encyclopedia of Geobiology has been designed to act as a key reference for students, researchers, teachers, and the informed public and to provide basic, but comprehensible knowledge on this rapidly expanding discipline that sits at the interface between modern geo- and biosciences.

A unique account of the biology, ecology and evolution of choanoflagellates - the closest, known, living, unicellular relatives of animals.

This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

The growing success of molecular methods has challenged traditional views of animal evolution and a large number of alternative hypotheses are hotly debated today. For the deep metazoan phylogeny project, data sets of hitherto unmatched quality and quantity were compiled and analysed with innovative bioinformatics tools. The book begins at the base of the tree of life to discuss the origin of animals and early branches of the phylogenetic tree. The following section presents special data sets gained from mitochondrial genomes and from morphology, with a focus on nervous systems. The final section is dedicated to theoretical aspects of data analysis and new bioinformatics tools. The book closes with a unique general discussion of all hypotheses contained in previous chapters. This work provides the most comprehensive overview available of the state of the art in this exciting field of evolutionary research.

The evolution of single cells into multicellular organisms was mediated, in large part, by the extracellular matrix. The proteins and glycoconjugates that make up the extracellular matrix provide structural support to cellular complexes, facilitate cell adhesion and migration, and impart mechanical properties that are important for tissue function. Each class of ECM macromolecule has evolved to incorporate distinctive properties that are defined by conserved modules that are mixed together to achieve appropriate function. This volume provides a comprehensive analysis of how the major ECM components evolved over time in order to fill their specific roles found in modern organisms. The major focus is on the structural matrix proteins, matricellular proteins, and more complex ECM structures such as basement membranes. Adhesive proteins and their receptors are also discussed.

Mitochondria are sometimes called the powerhouses of eukaryotic cells, because mitochondria are the site of ATP synthesis in the cell. ATP is the universal energy currency, it provides the power that runs all other life processes. Humans need oxygen to survive because of ATP synthesis in mitochondria. The sugars from our diet are converted to carbon dioxide in mitochondria in a process that requires oxygen. Just like a fire needs oxygen to burn, our mitochondria need oxygen to make ATP. From textbooks and popular literature one can easily get the impression that all mitochondria require oxygen. But that is not the case. There are many groups of organismsm known that make ATP in mitochondria without the help of oxygen. They have preserved biochemical relicts from the early evolution of eukaryotic cells, which took place during times in Earth history when there was hardly any oxygen avaiable, certainly not enough to breathe. How the anaerobic forms of mitochondria work, in which organisms they occur, and how the eukaryotic anaerobes that possess them fit into the larger picture of rising atmospheric oxygen during Earth history are the topic of this book.