Usted buscó por: "Webb, James W."

On the origin of phyla

Chicago : University of Chicago Press, 2004 copyright.
Descripción: xxiv, 614 páginas : ilustraciones

ISBN: 0226845486 (cloth)

Evidence of the Origins of Metazoan Phyla.The Nature of Phyla. Phyla Are Morphologically Based Branches of the Tree of Life. Genealogical Histories Can Be Traced in Trees, Which Are Positional Structures. Natural Biological Hierarchies Are Nested Structures of Functional Entities That Emerge When Complex Systems Are Organized. Natural Hierarchies Are Formed by Trees. The Linnean Hierarchy Is Quasi-Natural. Trees and Hierarchies Have Very Distinct Properties. Cladistics Is a Systematics Based on Trees. Phyla Have Split Personalities. Molecular Branchings Can Define Clades, while Morphological Features Define Linnean Taxa. Bodyplans Consist of Evolutionarily Disparate Features. Systematic Hierarchies and Trees: A Summary. Design Elements in the Bodyplans of Phyla. Cells Are the Basic Building Blocks of Metazoan Bodies. Cells Are Integrated into Tissues by Protein Bindings or Matrices. Metazoans Have Several Major Types of Tissues. Organs and Organ Systems Are Formed of Tissues. Many Bodyplan Features Reflect Locomotory Techniques. Symmetry and Seriation Are the Principal Descriptors of Body Style. Evolutionary Changes in Body Size Occur throughout Metazoan History. Morphological Complexity Is Not a Simple Topic. Development and Bodyplans. The Evolution of Developmental Systems Underpins the Evolution of Bodyplans. The English Language and Genomes Both Have Combinatorial, Hierarchical Structures. The Metazoan Gene Is a Complex of Regulatory, Transcribed, and Translated Parts. Regulatory Signals Are Produced by Trans-Regulatory Systems. Genomic Complexity Is a Function of Gene Numbers and Interactions. Metazoan Genomes Display Surprising Patterns of Similarities and Differences among Taxa. Developmental Genomes May Evolve on Many, Semidecomposable Levels. Regulatory Gene Systems Organize Complexity . Morphological and Molecular Phylogenies. Assumed Evolutionary Histories Affect Morphologically Based Phylogenetic Hypotheses. Many of the Classic Phylogenetic Hypotheses Involve Assumptions as to the Phylogenetic History of the Coelom. Evolutionary Histories Affect Molecularly Based Estimates of the Timing, Branching Patterns, and Order of Origins of Phyla. Morphological and Molecular Homologies Are Decomposable. There Is a Large Variety of Ways to Form Trees from Molecular Sequences. Although Molecular Phylogenies Produce Conflicting Topologies, They Have Also Produced a Growing Consensus on Major Alliances of Phyla. Combined Morphologica/Molecular Phylogenies of Phyla May Require Improved Assessments of Homologies to Be Successful. Stratigraphic Data Can Add Useful Information to Phylogenetic Hypotheses. The Alliances of Phyla Indicated by Molecular Methods Pro vide Evidence for Evaluating the Origin and Early History of Phyla.The Fossil Record. The Stratigraphic Record Is Incomplete in a Spotty Way. The Marine Fossil Record, while Incomplete, Yields Useful Samples of a Rather Consistent Fraction of the Fauna. There Are Ways of Coping with Incomplete Records. The Neoproterozoic-Cambrian Fossil Record Provides the Only Direct Evidence of Early Metazoan Bodyplans. There Is a Vast Range of Hypotheses That Attempt to Explain the Cambrian Explosion. In Sum, the Cambrian Fossils Imply an Explosion of Bodyplans, but the Underlying Causes Remain Uncertain

The Metazoan Phyla. Prebilaterians and Earliest Crown Bilaterians. Sponges and Spongiomorphs. Cnidarians and Cnidariomorphs. Ctenophora. Placozoa. Myxozoa. Diversification of Prebilaterian Metazoa. Acoelomorpha: Earliest Crown Bilaterians?. Protostomes: The Ecdysozoa. Priapulida. Kinorhyncha. Loricifera. Nematomorpha. Nematoda. Paleoscolecidae. Relationships of Paracoelomate Ecdysozoans. Onychophora. Tardigrada. Arthropoda. Some Branch Points within the Ecdysozoa. Early History of the Lobopodian and Arthropodan Clades. Protostomes: Lophotrochozoa: Eutrochozoans. Platyhelminthes: Rhabditophora and Catenulida. Mollusca and Mollusklike Forms. Annelida. Sipuncula. Nemertea. Mesozoans: Rhombozoa and Orthonectida. Fossil Groups That May Be Eutrochozoans.Possible Branch Points within Eutrochozoa. Protostomes: Lophotrochozoa : Lophophorates. Bryozoa. Phoronida. Brachiopoda. Lophophorate Relationships. Protostomes: Paracoelomates. Gastrotricha. Rotifera. Acanthocephala. Entoprocta. Cycliophora. Gnathostomulida. Chaetognatha. Phylogenetic Schemes for Paracoelomates. Deuterostomes. Hemichordata. Echinodermata. Vetulicolia. Invertebrate Chordata. Early Vertebrata

Evolution of the Phyla. Phanerozoic History of Phyla. Diversification Patterns of Higher Taxa with Mineralized Skeletons Can Be Evaluated by Richnesses and Disparities. Macroevolutionary Dynamics of Phyla Run the Gamut fram Stability to Volatility. Clade Histories of Invertebrate Taxa with Mineralized Skeletons Reflect Turnover Dynamics. Is the Number of Phyla Related to the Gross Heterogeneity of the Marine Environment?. The Late Neoproterozoic and Early Cambrian Pattern of Appearances Is Consistent with Patterns Found throughout the Phanerozoic. Metazoan Evolution during the Prelude to the Cambrian Explosion. Metazoan Multicellularity Evolved from Protistan Pluricellularity. Diploblastic Somatic Architecture Evolved from Sponges. The Nature of Early Bilateria Is Widely Debated. A Benthic Hypothesis Can Explain Both Fossil and Molecular Data and Is Not Incompatible with Developmental Patterns. Ectoderm, Endoderm, and Endomesoderm Are Probably Homologous throughout the Eumetazoa. Crown Paracoelomate Bodyplans Largely Represent a Radiation of Small-Bodied Protostomes. Metazoan Complexity Increased before the Cambrian Explosion, Perhaps Chiefly during the Early Cambrian. Metazoan Evolution during the Cambrian Explosion and Its Aftermath. Independent Trends in Body-Size Increases Produced the Major Bilaterian Alliances. The Homology of Body Cavities across Bilateria Is Unlikely. Systems Associated with Body Cavities, Such as Blood Vascular and Nephridial Systems, May Be Homoplastic. Body-Size Increases Are Consistent with the Early Cambrian Evolution of Planktotrophy and Divergences in Early Development. There Are Similarities in the Gross Morphological Adaptations of Some Phyla in the Separate Alliances. The Cambrian Explosion Produced Widespread Homoplasy: A Summary. Much Evolution of the Developmental Genome Occurred in the Service of Bodyplan Originations: A Summary. Why Are Problems of Early Metazoan Evolution So Hard?.

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