Sökning: "geographic variation"

Visar resultat 1 - 5 av 115 avhandlingar innehållade orden geographic variation.

  1. 1. Geographic Distribution of Intra-specific Variation in Widespread Eurasian boreo-nemoral Woodland Herbs

    Författare :Torbjörn Tyler; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; kemotaxonomi. Växters fysiologi inte kärlväxter .; Plant genetics; Växtgenetik; morfologi; chemotaxonomy. Physiology of nonvascular plants; Systematisk botanik; taxonomi; phytogeography; morphology; taxonomy; historical biogeography; Systematic botany; allozymes; population differentiation; postglacial migration; genetic variation; geographic variation;

    Sammanfattning : Many woodland plant species have huge distribution areas covering large parts of the Eurasian continent including areas that were glaciated during the last glacial period. In the present thesis, the geographic distribution of variation within such species is investigated and discussed in relation to glacial survival and post-glacial migration, dispersal ability, breeding system and levels of gene-flow between populations and related species, and various methods to measure and analyse genetic variation. LÄS MER

  3. 2. Geographic variation in life cycles : Local adaptation and ecological genetics in a temperate butterfly

    Författare :Olle Lindestad; Karl Gotthard; Sören Nylin; Christopher W Wheat; Greg Ragland; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; voltinism; local adaptation; insect; life cycle; seasonality; genomics; life history; zoologisk ekologi; Animal Ecology;

    Sammanfattning : Conditions in nature change with the seasons, necessitating seasonal adaptations that synchronize the life cycles of organisms with their surroundings. Such regulatory adaptations must vary between populations to track local variation in climate and seasonality; this local adaptation is facilitated by locally specific seasonal cues, but may be hampered by gene flow and genetic history. LÄS MER

  4. 3. Genetic variation in structured populations

    Författare :Marina Rafajlovic; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; genetic variation; varying population size; effective population size; mutation; recombination; migration; multiple paternity; geographic structure; tests of neutrality; gene tree; species tree;

    Sammanfattning : It is widely acknowledged that the process of speciation in the presence of gene flow between different ecotypes is common in nature. However, the mechanisms underlying speciation are not understood. LÄS MER

  5. 4. Patterns of geographic variation in Silene section Elisanthe (Caryophyllaceae): hybridization and migrational history

    Författare :Louise Hathaway; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chemotaxonomy. Physiology of nonvascular plants; phytogeography; morphology; outbreeding depression; Systematic botany; taxonomy; ITS; fitnes; inbreeding depression; AFLP; PCR-RFLP; cpDNA; gene flow; postglacial migration; geographic variation; hybridization; Silene latifolia; Silene section Elisanthe; Silene dioica; Systematisk botanik; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .;

    Sammanfattning : Large-scale patterns of genetic variation in chloroplast (cp) and nuclear DNA in the widespread European herb species Silene latifolia and S. dioica were investigated using cpPCR-RFLPs, non-coding cpDNA sequences, AFLPs and sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA (rDNA). LÄS MER

  7. 5. Morphometric differentiation in Papaver radicatum (Papaveraceae) : Geographic pattern and significance for refugial survival theory

    Författare :Eva Selin; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Capsule morphology; Geographic pattern; Leaf morphology; Morphometric variation; Papaver radicatum; Refugial survival; Seed shape; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The morphometric pattern of variation among and within Scandinavian populations of the alpine species Papaver radicatum was studied. Results from analyses (including multivariate techniques) of capsule and leaf traits of wild-collected and cultivated plants as well as wild-collected seeds show correlated patterns of variation in capsule traits and partly corresponding patterns of variation between capsule and seed traits. LÄS MER