Sökning: "taxon"

Visar resultat 16 - 20 av 63 avhandlingar innehållade ordet taxon.

  1. 16. Comparative morphological studies of fossil and living plane trees (Platanaceae) and oaks (Quercus): taxonomy, ecology, evolution

    Författare :Georg Florian Tschan; Thomas Denk; Ove Eriksson; Bertil Ståhl; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Platanaceae; Platanus; Credneria; Quercus; Galliferae; leaf architecture; epidermal anatomy; comparative morphology; character variation; variability; sample size; diversity patterns; species concepts; ecology; biogeography; evolution; plant fossils; Plant Ecology; växtekologi;

    Sammanfattning : Morphological characters are essential for flowering plant identification, but also provide information about diversity patterns and ecological adaptation. In woody plant species, characters of the leaf are among the most useful and can be examined on fossils as well. LÄS MER

  3. 17. Diversity and phylogeography in Alisma (Alismataceae), with emphasis on Northern European taxa

    Författare :Anders Jacobson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; morphology; phytogeography; chemotaxonomy. Physiology of nonvascular plants; taxonomy; Systematic botany; Baltic Sea; Europe; refugia; post-glacial migration; phylogeography; marsh plants; genetic variation; aquatic plants; Alisma; Systematisk botanik; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .;

    Sammanfattning : In the present thesis the phylogeny and patterns of genetic diversity of the plant genus Alisma (Alismataceae) were investigated by means of genetic markers (RAPDs, allozymes, and ITS and trnL sequences). Additionally, morphological studies were carried out in paper IV. LÄS MER

  4. 18. Phylogeny and Taxonomy of Polyblastia and allied taxa (Verrucariaceae)

    Författare :Sanja Savić; Leif Tibell; Bengt Oxelman; Martin Grube; Uppsala universitet; []
    Nyckelord :Biology; Phylogeny; Taxonomy; ITS; LSU; RPB1; Nomenclature; Biologi; Polyblastia; Verrucariaceae; Sporodictyon; Atla; Thelidium; Verrucaria; Staurothele; Trimmatothele;

    Sammanfattning : Polyblastia A. Massal. is a genus of lichenized fungi belonging to Verrucariaceae (Ascomycota). Traditional classification heavily rested on a few cardinal characters, primarily ascoma structure and spore morphology, but the delimitation of Polyblastia was problematic. LÄS MER

  5. 19. Fossil birds: Contributions to the understanding of avian evolution

    Författare :Johan Dalsätt; Otto Hermelin; Per Ericson; Zbigniew M. Bocheński; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; General and Historical Geology; allmän och historisk geologi;

    Sammanfattning : The study of the evolution of birds began about 150 years ago with the finding of Archaeopteryx. Yet, many unsolved questions about avian evolution remain to be answered. This thesis aims at addressing some of these questions.The Early Cretaceous Confusiusornis is the most well-represented Mesozoic bird in the fossil record. LÄS MER

  7. 20. The Genetics of Speciation and Colouration in Carrion and Hooded Crows

    Författare :Jelmer Poelstra; Jochen Wolf; Hans Ellegren; Chris Jiggins; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; evolutionary genetics; genomics; birds; next-generation sequencing; pigmentation; pigmentation genetics; eumelanin; social selection; gene expression; population genomics; Biology with specialization in Evolutionary Genetics; Biologi med inriktning mot evolutionär genetik;

    Sammanfattning : A fundamental goal in biological research is to gain an understanding of the evolutionary processes and genetic elements that drive speciation. Genes responsible for reproductive isolation in young divergent lineages are particularly poorly known. In this thesis, the speciation genetics of carrion (Corvus (corone) corone) and hooded (C. LÄS MER