Sökning: "molecular phylogenies"

Visar resultat 1 - 5 av 25 avhandlingar innehållade orden molecular phylogenies.

  1. 1. Dating Divergence Times in Phylogenies

    Författare :Cajsa Lisa Anderson; Kåre Bremer; Katleen M. Pryer; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; systematic biology; divergence time; nonprametric rate smoothing; Bayesian; multidivtime; eudicots; Neoaves; monocots; dating; molecular clock; relaxed clock; age constraint; fossil; calibration; PATHd8; penalized likelihood; Biology; Biologi;

    Sammanfattning : This thesis concerns different aspects of dating divergence times in phylogenetic trees, using molecular data and multiple fossil age constraints.Datings of phylogenetically basal eudicots, monocots and modern birds (Neoaves) are presented. Large phylograms and multiple fossil constraints were used in all these studies. LÄS MER

  3. 2. Taxonomy and Phylogeny of Catenulida (Platyhelminthes) with Emphasis on the Swedish Fauna

    Författare :Karolina Larsson; Ulf Jondelius; Lena Gustavsson; Isabell Sanmartin; Tom Artois; Uppsala universitet; []
    Nyckelord :Biology; taxonomy; phylogeny; molecular phylogenies; cryptic species; micro-invertebrate; Biologi; Catenulida; Platyhelminthes;

    Sammanfattning : This thesis focuses on phylogenetic and taxonomic studies of Catenulida (Platyhelminthes). Catenulida is a group of microscopic free-living worms mainly found in freshwater habitats. The Swedish catenulid fauna was previously virtually unknown. LÄS MER

  4. 3. The Gnetales: fossils and phylogenies

    Författare :Catarina Rydin; Else Marie Friis; Mari Källersjö; Ulf Swensson; Susana Magallón; Stockholms universitet; []
    Nyckelord :seed plants; Gnetales; Ephedra; fossils; DNA; phylogeny; morphology;

    Sammanfattning : The phylogeny of seed plants has been debated for more than a hundred years and is still not fully understood. Morphological analyses have consistently resulted in a phylogeny in which cycads are the earliest diverging seed plants, and Gnetales and angiosperms are sisters. Molecular data has, however, rarely supported this result. LÄS MER

  5. 4. Next-generation Molecular Systematics and Evolution: insights into Medicago

    Författare :Filipe de Sousa; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; phylogeny; incomplete lineage sorting; paralogy; hybridisation; Medicago;

    Sammanfattning : Evolutionary relationships among species have in recent years been inferred using DNA sequences from specific genes and represented by tree diagrams (phylogenies). However, the signal contained in different genes can produce conflicting sets of relationships – i.e., gene tree incongruence. LÄS MER

  7. 5. Molecules and morphology in Empidoidea (Diptera) : Phylogenetic analysis and taxonomical implications

    Författare :Emma Wahlberg; Kjell Arne Johanson; Thomas Pape; Jeffrey Cumming; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Empidoidea; Empididae; Hybotidae; phylogeny; taxonomy; systematics; molecular data; morphology; revision; Systematic Zoology; zoologisk systematik och evolutionsforskning;

    Sammanfattning : The classification and evolutionary history of the superfamily Empidoidea (Diptera) have been far from straightforward subjects. Morphology based phylogenies of the superfamily have been unable to answer many questions raised by both systematists and biogeographers, as well as ecologists and ethologists, partly due to morphological modifications and adaptations difficult to interpret. LÄS MER