Molecular Evolution Towards the Origin of Metazoa [Paperback]

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.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.The Question of Metazoan Monophyly and the Fossil Record.- 1 Introduction.- 2 The Rise of Metazoans.- 2.1 Are Metazoans Monophyletic?.- 2.1.1 Primitive Metazoans.- 3 Fossil Evidence for the Early Evolution of Metazoans.- 4 The Search for Pre-Ediacaran Metazoans.- 5 Where Do We Go from Here?.- 5.1 What is the Sister Group (or Sister Groups) of the Metazoans, and Will the Fossil Record Yield any Insights?.- 5.2 What Are the Inter-Relationships of the Primitive Metazoans, Notably the Sponges, Cnidarians, and Perhaps the Ctenophores?.- 5.3 Metazoan Evolution and Convergence: What Are the Constraints?.- References.- The Evolution of the Lower Metaló'