Sökning: "bird"

Visar resultat 16 - 20 av 204 avhandlingar innehållade ordet bird.

  1. 16. Avian MHC: variation and selection in the wild

    Författare :Helena Westerdahl; MEMEG; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; polymorphism; balancing selection; cDNA; avian malaria; great reed warbler; Djurekologi; bird; Animal ecology; immune defence; MHC class II; Major Histocompatibility Complex; MHC class I;

    Sammanfattning : In vertebrates the Major Histocompatibility Complex (MHC) plays a central role in the specific immune defence against various pathogens. Compared with other coding genes the MHC genes exhibit an extremely high level of polymorphism that is maintained by balancing selection. LÄS MER

  3. 17. Quantitative Genetics and Genome Structure in a Wild Population: the Use of a Great Reed Warbler Pedigree

    Författare :Mikael Åkesson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; genome mapping ; AFLP; microsatellite; synteny; heterochiasmy; recombination; chicken; great reed warbler ; bird; Genetics; cytogenetics; Genetik; cytogenetik; Animal ecology; trait correlation ; Djurekologi; animal model ; selection; Djurs anatomi och morfologi; animal morphology; Animal anatomy; heritability;

    Sammanfattning : Long-term studies of birds play an important role in the understanding of quantitative traits in natural populations. The relative ease by which individual birds can be monitored and caught in the wild enable us collect detailed information from individuals throughout their life time, sometimes from several generations in a population. LÄS MER

  4. 18. Living in a Variable Environment : Reproductive Decisions in Wild Bird Populations

    Författare :Mårten B. Hjernquist; Lars Gustafsson; Marcel Visser; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; evolutionary ecology; competition; sex allocation; paternity; EPP; inadvertent social information; migration; breeding density; territory quality; territory availability; great tit; blue tit; Ficedula albicollis; Biology; Biologi; Animal Ecology; zooekologi;

    Sammanfattning : In nature, environments are often variable and heterogeneous influencing ecological and evolutionary processes. This thesis focus on how animals interact with their environment and how that affects the reproductive decisions they make. LÄS MER

  5. 19. Clades in the "higher land bird assemblage"

    Författare :Ulf. S. Johansson; Scott V. Eswards; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Birds; Fåglar; Systematic Zoology; zoologisk systematik och evolutionsforskning;

    Sammanfattning : This thesis summarizes the results of several phylogenetic studies of birds included in the “higher land bird assemblage” (Anomalogonatae sensu Beddard 1898). The phylogenetic analyses are primarily based on gene sequences obtained from the nuclear genome (exons of the c-myc and RAG-1 genes and an intron of the myoglobin gene). LÄS MER

  7. 20. Bird orientation: external cues and ecological factors

    Författare :Johan Bäckman; Evolutionär ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tracking radar; Emlen funnel.; Animal ecology; Djurekologi; oscillatory orientation; roosting flight; scatter; concentration; heading; cue calibration; light dependent; magnetoreception; subcutaneous fat stores; body condition; energetics; geomagnetic field; visual cues; orientation; birds; migration;

    Sammanfattning : Birds are generally capable of accurate orientation. In this thesis I present studies about the external cues and the ecological factors that influences bird orientation. A multitude of environmental cues are used to select and maintain a proper direction. LÄS MER