Sökning: "floral shifts"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden floral shifts.

  1. 1. Selection and Floral Evolution in Platanthera bifolia and P. chlorantha (Orchidaceae)

    Författare :Johanne Maad; Charles B. Fenster; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; Evolution; phenotypic selection; male function hypothesis; mating systems; floral shifts; orchids; pollination; moth pollinators; Platanthera.; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; systematisk botanik; Systematic Botany;

    Sammanfattning : Natural selection mediated by pollinators has influenced the evolution of floral diversity of the flowering plants (angiosperms). The scope of this thesis was to study: 1) phenotypic selection, 2) mating systems, and 3) floral shifts involved in plant speciation. Model plant species were Platanthera bifolia and P. chlorantha (Orchidaceae). LÄS MER

  3. 2. The evolutionary ecology of plant reproductive diversity and floral signals : Mating system and floral scent in Arabis alpina

    Författare :Hampus Petrén; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Arabis alpina; floral scent; intraspecific variation; mating system; parental conflict; phenotypic plasticity; phenotypic selection; reproductive isolation; speciation; volatile organic compound VOC ;

    Sammanfattning : Flowering plants display an extraordinary floral- and reproductive diversity. Variation in the size, shape, colour and scent of flowers, and in systems and strategies of mating, is ubiquitous in comparisons of different species, but also exists among different conspecific populations. LÄS MER

  4. 3. Evolution of Spur Length in a Moth-pollinated Orchid

    Författare :Elin Boberg; Jon Ågren; W. Scott Armbruster; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Platanthera bifolia; floral evolution; natural selection; pollination; spur length; population differentiation; divergent selection; disruptive selection; reproductive isolation; Biology; Biologi; Ecological Botany; Ekologisk botanik;

    Sammanfattning : There is considerable evidence that pollinator shifts can explain many differences in flower morphology between closely related plant species, but the extent to which pollinator shifts can explain the maintenance of among-population variation in floral traits within species is poorly known. In this thesis, I combined comparative and experimental approaches to examine the evolution of floral traits in the moth-pollinated orchid Platanthera bifolia. LÄS MER

  5. 4. Cis-regulatory variation and divergence in Capsella

    Författare :Kim A. Steige; Tanja Slotte; Jeff J. Doyle; Uppsala universitet; []
    Nyckelord :Capsella; Shepherd s Purse; cis-regulatory changes; allele-specific expression; mating system shift; floral evolution; polyploidy; positive selection; purifying selection; transposable elements; small RNA; methylation; transposable element silencing; distribution of fitness effects;

    Sammanfattning : Cis-regulatory changes in e.g. promoters or enhancers that affect the expression of a linked focal gene have long been thought to be important for adaptation. In this thesis, I investigate the selective importance and genomic correlates of cis-regulatory variation and divergence in the genus Capsella, using massively parallel sequencing data. LÄS MER

  7. 5. Biotic and abiotic drivers of life-history and demographic variation in boreal orchids

    Författare :Matthew R. Tye; Nina Sletvold; Yvonne Buckley; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plant demography; life-history; climate; pollination; compensation; orchids; resources; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

    Sammanfattning : Environmental interactions, including both abiotic and biotic factors, are key drivers of life-history and population dynamics. Despite this, most population studies do not explicitly link variation in environmental factors and vital rates. LÄS MER