Sökning: "asexual reproduction"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden asexual reproduction.

  1. 1. Metapopulation and metacommunity processes, dispersal strategies and life-history trade-offs in epiphytes

    Författare :Swantje Löbel; Håkan Rydin; Tord Snäll; Lars E. Ericson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asexual; biodiversity; bryophytes; dispersal limitation; establishment; evolution of reproductive traits; germination; growth; habitat fragmentation; landscape dynamics; local processes; patch-tracking; pH; reproduction; species richness; species interactions; Other biology; Övrig biologi; Ecological Botany; Ekologisk botanik;

    Sammanfattning : The aim of this thesis was to increase knowledge about metapopulation and metacommunity processes in patchy, dynamic landscapes, using epiphytic bryophytes as a model system. Host trees and deciduous forest stands in the coniferous landscape are patchy, temporal and undergo changes in habitat quality during succession. LÄS MER

  3. 2. On enchytraeids and naidids: Life history traits and responses to environmental stress

    Författare :Anna-Karin Augustsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; oligochaeta; terrestrial naididae; toxicity testing; asexual reproduction; sexual reproduction; drought; environmental stress; metal pollution; Ekologi; Animal ecology; Djurekologi;

    Sammanfattning : My thesis shows that enchytraeids and naidids are sensitive to various forms of environmental stress, which in combination with the wide distribution of both families make them highly suitable for use in risk assessment and soil monitoring. Enchytraeids were subject to chemical stress under both laboratory and field conditions. LÄS MER

  4. 3. Macroalgae in the Baltic Sea : responses to low salinity and nutrient enrichment in Ceramium and Fucus

    Författare :Lena Bergström; Lars Ericson; Lena Kautsky; Erik Bonsdorff; Christine A Maggs; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; adaptation; asexual reproduction; Baltic Sea; Gulf of Bothnia; salinity; macroalgae; nutrients; sexual reproduction; stress; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The brackish Baltic Sea is a marginal environment for both marine and freshwater species. The rate of ecological differentiation is presumably high due to strong selection pressure from a gradient of decreasing salinity that has been present in its current state for only about 3 000 years. LÄS MER

  5. 4. Herbivory, phenotypic variation, and reproductive barriers in fucoids

    Författare :Helena Forslund; Lena Kautsky; Ove Eriksson; Stein Fredriksen; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Non-indigenous species; Enemy Release Hypothesis; Asexual reproduction; Phlorotannins; Distribution; Plant Ecology; växtekologi;

    Sammanfattning : Along the shores of the Northern hemisphere Fucus (Phaeophyceae) species are a prominent presence, providing substrate, shelter, and food for many species. Fucus evanescens, a non-indigenous species (NIS) in Sweden, and F. LÄS MER

  7. 5. The balance between sex and asex: evolutionary genetic studies of reproductive variation in Allium vineale

    Författare :Alf Ceplitis; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ontogeny; growth animal ; Allium vineale; Development biology; evolution; sexual reproduction; reproductive systems; embryology; Utvecklingsbiologi; ontogeni; embryologi; Genetics; cytogenetics; Genetik; cytogenetik;

    Sammanfattning : Evolutionary theory predicts a disadvantage to sexual reproduction. This manifests itself either by the higher growth rate of asexual females in a dioecious species, or by the higher transmission rate of a gene conferring asexual female function to its carriers in a hermaphrodite species. LÄS MER