Sökning: "niche"

Visar resultat 1 - 5 av 256 avhandlingar innehållade ordet niche.

  1. 1. Genome Evolution and Niche Differentiation of Bacterial Endosymbionts

    Författare :Kirsten Maren Ellegaard; Siv Andersson; Andrés Moya; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; niche; habitat; endosymbiont; gut microbiome; honey bee; Wolbachia; comparative; genomics;

    Sammanfattning : Most animals contain chronic microbial infections that inflict no harm on their hosts. Recently, the gut microflora of humans and other animals have been characterized. However, little is known about the forces that shape the diversity of these bacterial communities. LÄS MER

  2. 2. Causes and consequences of niche differentiation between color morphs of pygmy grasshoppers

    Författare :Einat Karpestam; Anders Forsman; Birgitta Tullberg; Linnéuniversitetet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; color polymorphism; visual predators; Tetrix subulata; differential habitat use; niche; thermoregulation; feeding preferences; stable isotopes; Evolutionary Biology; Evolutionsbiologi;

    Sammanfattning : In this thesis, I used the color polymorphic pygmy grasshopper, Tetrix subulata, as a model system in order to investigate the degree of niche differentiation between alternative color morphs that are present within a single population. First, I hypothesized that individuals belonging to different color morphs differ in their innate food preference due to somewhat dissimilar physiology, and in their actual food consumption due in part to differential habitat use. LÄS MER

  3. 3. Evolutionary ecology of arctic char (Salvelinus alpinus (L.)) : Intra- and interspecific interactions in circumpolar populations

    Författare :Johan Hammar; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ecology; Arctic char; Salvelinus alpinus; biogeography; niche; life history; population ecology; intra- and interspecific interactions; cannibalism; competition; landlocked; marginal populations; species border; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; Animal Ecology; zooekologi;

    Sammanfattning : This thesis examines a suite of ecological and genetic mechanisms influencing the fundamental and realized niche borders of European and North American populations of the Arctic char (Salvelinus alpinus (L.)) species complex in allopatry as well as in sympatry with brown trout (Salmo trutta) or brook trout (Salvelinus fontinalis). LÄS MER

  4. 4. Species interactions in streams - effects of predation, competition and ecosystem properties

    Författare :Erika Nilsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; behaviour; species abundance; stable isotopes; habitat complexity; niche width; niche overlap; competition; streams; predation;

    Sammanfattning : Stream ecosystems are dynamic and they have an inherent environmental variability. Organisms that live in streams are adapted to the continuously changing environment and the presence or absence of species are determined by their environmental requirements, while abundance is most often affected by interactions, such as competition and predation, with other species that are found in the same habitat. LÄS MER

  5. 5. Genetic variation, clonal diversity and breeding system in sedges (Carex)

    Författare :Olle Jonsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Systematic botany; Carex ericetorum; Carex caryophyllea; Carex bigelowii; Carex arenaria; phenology; niche; genet identification; clone size; isozyme; gene flow; introgression; allozyme; gene diversity; population genetics; taxonomy; morphology; phytogeography; chemotaxonomy. Physiology of nonvascular plants; Systematisk botanik; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .;

    Sammanfattning : In this thesis I investigate genetic variation in clonal plants within the wind-pollinated plant family Cyperaceae and, in particular, in species of Carex. Clonal diversity and the spatial distribution of clones (genets) within populations was investigated in Carex bigelowii (in Iceland and Scandinavia) and C. LÄS MER