Description

A unique account of the biology, ecology and evolution of choanoflagellates - the closest, known, living, unicellular relatives of animals. Choanoflagellates are the closest known living, unicellular relatives of animals. This landmark book presents a unique, comprehensive discussion of choanoflagellates with respect to their ultrastructure, silicon utilisation for skeletal purposes, contribution to microbial food webs, and molecular phylogeny. Also included is a novel account of the production of the basket-like lorica. Choanoflagellates are the closest known living, unicellular relatives of animals. This landmark book presents a unique, comprehensive discussion of choanoflagellates with respect to their ultrastructure, silicon utilisation for skeletal purposes, contribution to microbial food webs, and molecular phylogeny. Also included is a novel account of the production of the basket-like lorica. Choanoflagellates have three distinctive claims to fame: they are the closest, living, unicellular relatives of animals; they are a major component of aquatic microbial foodwebs; and one group is remarkable for its siliceous basket-like coverings. This landmark book offers a unique synthesis of over forty years of choanoflagellates research. Key areas are covered, from the phylogenetic evidence supporting the sister-group relationship between choanoflagellates and Metazoa, to choanoflagellate distribution and diversity in marine and freshwater environments. The structure and assembly of choanoflagellate loricae is also presented together with a full discussion of a novel example of 'regulatory evolution', suggesting that the switch from nudiform to tectiform cell division and lorica production was achieved by a sudden reorganisation of existing structures and mechanisms. Providing an authoritative summary of what is currently known about choanoflagellates, this title will serve as a foundation upon which future research and discussion can take place. Preface; 1. Historical perspectives; 2. The collared flagellate: functional morphology and ultrastructure; 3. Craspedida: choanoflagellates with exclusively organic coverings; 4. Loricate choanoflagellates: Acanthoecida; 5. Loricate choanoflagellates: requirement for silicon and its deposition in costal strips; 6. Loricate choanoflagellates: Acanthoecidae – nudiform species; 7. Loricate choanoflagellates: Stephanoecidae – tectiform species; 8. Loricate choanoflagellates: evolutionary relationship between the nudiform and tectiform conditions; 9. Choanoflagellate ecology; 10. Choanoflagellate phylogeny: evolution of metazoan multicellularity; Glossary; Figure credits; References; Index. 'We look around and see a world full of animals, plants and fungi, but our eyes are deceptive. Most life on Earth is microscopic. Amongst the great diversity of single-celled life, the choanoflagellates deserve our special attention. As well as being important ecologically, choanoflagellates occupy a position of pivotal significance in the evolution of life. They are the closest single-celled relatives of the animal kingdom. To understand how animals evolved, we must study choanoflagellates. In this landmark book, Barry Leadbeater ranges from ecology and evolution, through to cell biology and ultrastructure, to reveal the secrets and the significance of these important and amazingly beautiful organisms.' Peter Holland, University of Oxford 'Leadbeater is the world's foremost authority on choanoflagellates and has