Sökning: "jawed vertebrates"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden jawed vertebrates.

  1. 1. Endocranial Morphology and Phylogeny of Palaeozoic Gnathostomes (Jawed Vertebrates)

    Författare :Martin D. Brazeau; Per Ahlberg; Graham Budd; Henning Blom; Michael Coates; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; systematics; palaeontology; anatomy; evolution; Organism biology; Organismbiologi;

    Sammanfattning : Gnathostomes, or jawed vertebrates, make up the overwhelming majority of modern vertebrate diversity. Among living vertebrates, they comprise the chondrichthyans (“cartilaginous fishes” such as sharks, skates, rays, chimaeras) and the osteichthyans (“bony fishes” or bony vertebrates, inclusive of tetrapods). LÄS MER

  2. 2. Silurian vertebrates of Gotland (Sweden) and the Baltic Basin

    Författare :Oskar Bremer; Henning Blom; Per E. Ahlberg; Tiiu Märss; Héctor Botella; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; early vertebrates; vertebrate microremains; scale taxonomy; early vertebrate distribution; environmental preferences; Silurian; Baltic Basin; Gotland; Sweden; Biology with specialization in Evolutionary Organismal Biology; Biologi med inriktning mot evolutionär organismbiologi;

    Sammanfattning : During the Silurian, the Swedish island Gotland was positioned close to the equator and covered by a shallow sea called the Baltic Basin. The sedimentary rocks (predominantly carbonates) comprising most of the island today were initially formed in this warm sea, and the relatively complete succession of rocks often contains fossil fragments and scales from early vertebrates, including heterostracans, anaspids, thelodonts, osteostracans, acanthodians, and a stem-osteichthyan. LÄS MER

  3. 3. Three-dimensional Virtual Histology of Early Vertebrate Scales Revealed by Synchrotron X-ray Phase-contrast Microtomography

    Författare :Qingming Qu; Per Ahlberg; Henning Blom; Moya Smith; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; 3D virtual paleohistology; scales; ontogeny; jawed vertebrates; phylogeny; Biology; Biologi; Earth Science with specialization in Historical Geology and Palaeontology; Geovetenskap med inriktning mot historisk geologi och paleontologi;

    Sammanfattning : Vertebrate hard tissues first appeared in the dermal skeletons of early jawless vertebrates (ostracoderms) and were further modified in the earliest jawed vertebrates. Fortunately, histological information is usually preserved in these early vertebrate fossils and has thus been studied for more than a century, done so by examining thin sections, which provide general information about the specific features of vertebrate hard tissues in their earliest forms. LÄS MER

  4. 4. Basal Vertebrate Divergences from a Molecular Perspective

    Författare :Ann-Sofie Rasmussen; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; mitochondrial genomes; Agnatha; Chondrichthyes; vertebrates; evolution; systematics; Genetics; cytogenetics; Genetik; cytogenetik;

    Sammanfattning : Fishes (Superclass Pisces) constitute the most numerous and morphologically diverse vertebrate group, yet only a small fraction of all molecular evolutionary studies concern piscine evolution. This thesis aims to investigate the vertebrate tree, through the analysis of mitochondrial (mt) DNA sequences. LÄS MER

  5. 5. Bioinformatics studies on the mechanisms of gene regulation in vertebrates

    Författare :Awaisa Ghazal; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []

    Sammanfattning : Gene regulation implicates an important role in organismal complexity through contributing to phenotypic variation. In my thesis, I studied three diverse components of gene regulatory networks including transcription factors, DNA methylation and microRNAs to elucidate their role in vertebrates. LÄS MER