Sökning: "Bengt Oxelman"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Bengt Oxelman.

  1. 1. Adaptation and Constraint in the Plant Reproductive Phase

    Författare :Kjell Bolmgren; Ove Eriksson; Bengt Oxelman; Jeff Ollerton; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; phenology; fleshy fruits; phylogenetic comparative methods; phylogenetic constraints; Rhamnus; Frangula; Frangula alnus; key innovations; allometry; diversity; phylogeny; seed size; frugivory; germination; recruitment; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

    Sammanfattning : Conservatism is a central theme of organismic evolution. Related species share characteristics due to their common ancestry. Some concern have been raised among evolutionary biologists, whether such conservatism is an expression of natural selection or of a constrained ability to adapt. LÄS MER

  3. 2. Systematics in Sileneae (Caryophyllaceae) – Taxonomy and Phylogenetic patterns

    Författare :Frida Eggens; Bengt Oxelman; Magnus Lidén; Susan R. Kephart; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sileneae; Silene; RNAP; psbE-petG; ITS; rps16; relative dating; Rigidulae; Heliosperma; Arenosae; phylogeny; homoploid reticulate evolution; Silene linearis Decne.; Silene polyphylla L.; Hawaiian Silene; Systematics and phylogenetics; Systematik och fylogeni;

    Sammanfattning : The focus for the first part of the thesis is on the systematics of species belonging to Silene subgenus Silene. Phylogenetic relationships are inferred from DNA sequences from both the plastid (the rps16 intron) and the nuclear (ITS, intron of the RPB2 gene) genomes. LÄS MER

  4. 3. Phylogenetic Support and Chloroplast Genome Evolution in Sileneae (Caryophyllaceae)

    Författare :Per Erixon; Bengt Oxelman; Sean Graham; Uppsala universitet; []
    Nyckelord :Biology; Phylogenetics; Bayesian inference; Bootstrapping; cpDNA; Sileneae; Interspecific chloroplast recombination; Hybridization; clpP; Positive selection; Extreme substitution rates; Biologi;

    Sammanfattning : Evolutionary biology is dependent on accurate phylogenies. In this thesis two branch support methods, Bayesian posterior probablities and bootstrap frequencies, were evaluated with simulated data and empirical data from the chloroplast genome. LÄS MER

  5. 4. Taxonomy and Reticulate Phylogeny of Heliosperma and Related Genera (Sileneae, Caryophyllaceae)

    Författare :Božo Frajman; Bengt Oxelman; Mats Thulin; Christian Brochmann; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sileneae; Silene; Heliosperma; Atocion; Viscaria; taxonomy; phylogenetics; relative dating; reticulate evolution; chloroplast capture; homoploid hybridisation; BEAST; r8s; PATHd8; Prometheus; RPA2; RPB2; RPD2a; RPD2b; Balkan Peninsula; endemics; Systematics and phylogenetics; Systematik och fylogeni;

    Sammanfattning : Heliosperma (nom. cons prop.) comprises 15—20 taxa, most of them endemic to the Balkan Peninsula. DNA sequences from the chloroplast (rps16 intron, psbE-petG spacer) and the nuclear genome (ITS and four putatively unlinked RNA polymerase genes) are used to elucidate phylogenetic relationships within Heliosperma, and its position within Sileneae. LÄS MER

  7. 5. Systematics and polyploid evolution in Potentilleae (Rosaceae)

    Författare :Magnus Lundberg; Torsten Eriksson; Jürg Schönenberger; Bengt Oxelman; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Potentilleae; Fragariinae; Potentilla; Sibbaldia; Fragaria; Alchemilla; systematics; phylogeny; polyploidy; autopolyploidy; allopolyploidy; reticulate evolution; Systematics and phylogenetics; Systematik och fylogeni; växtsystematik; Plant Systematics;

    Sammanfattning : This thesis comprises studies of the phylogenetic relationships in the flowering plant clade Potentilleae in Rosaceae. The relationships were elucidated by using DNA sequence data from the nuclear genome as well as from the plastid genome. In particular, the focus of the studies was the investigation of allopolyploidy, i.e. LÄS MER