Sökning: "Body size evolution"

Visar resultat 21 - 25 av 45 avhandlingar innehållade orden Body size evolution.

  1. 21. Splitting the sexes : The birth and senescence of sex chromosomes

    Författare :Aivars Cirulis; Evolutionär ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sex chromosome; Sexual conflict; Macrostomum lignano; Experimental evolution; Genomics of sex;

    Sammanfattning : The evolution of gonochorism from hermaphroditism can be gradual by increasing investment in one sex role while decreasing in the other, or rapid through the fixation of sex-role sterility mutations, eventually leading to the evolution of sex chromosomes. It is expected that the transition will involve a temporary state of gynodioecy or androdioecy as the mutations are not expected to take place at the same time. LÄS MER

  3. 22. The effects of temperature on avian physiology, behavior and development

    Författare :Andreas Nord; Evolutionär ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; clutch size; Cyanistes caeruleus; ecological immunology; energy expenditure; fever; Ficedula hypoleuca; heterothermy; hypothermia; incubation; life history; metabolic rate; Parus major; RMR; Taeniopygia guttata; temperature; winter;

    Sammanfattning : Temperature is a property of profound matter in all aspects of animal life, affecting both individual energy budgets and the environments in which animals reside. Thus, a proper understanding of the effects of temperature variation is instrumental in understanding not only animal form and function, but also the structure and dynamics of wild populations. LÄS MER

  4. 23. Comparative Population Ecology in Moor Frogs with Particular Reference to Acidity

    Författare :Fredrik Söderman; Anssi Laurila; Jacob Höglund; Juha Merilä; J.W (Pim) Arntzen; Uppsala universitet; []
    Nyckelord :Biology; Amphibians; Life-history; Trade-off; Environmental stress; Local adaptation; Acidity; Biologi;

    Sammanfattning : This thesis is an attempt to describe how different environmental factors influence life history traits in different populations, sexes and developmental stages in the moor frog, Rana arvalis. The studied populations are located along 1100 km latitudinal gradient, with pH varying between 4.0 and 8.5. LÄS MER

  5. 24. Genetic variation and phenotypic plasticity in body traits of nestling blue tits

    Författare :Camilla Kunz; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; populationsbiologi; Population Biology;

    Sammanfattning : This thesis examines genetic and environmental contributions to variation in body traits in a population of free-living blue tits. It also investigates possible consequences for the evolution of body size. LÄS MER

  7. 25. Causes and consequences of quantitative trait variation for reproductive performance in hole nesting birds

    Författare :Robert Przybylo; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; timing of breeding; climate change; parental and territorial quality; morphology; sexual size dimorphism; intersexual niche differentiation; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; Animal Ecology; zooekologi;

    Sammanfattning : This thesis examines the causes and consequences of environmental variability and individual morphological differences on breeding success and survival in three hole nesting birds.An analysis of directional and stabilising natural selection in Collared Flycatchers (Ficedula albicollis) suggested that forces of selection acting on quantitative traits are weak and cannot explain the observed sexual size dimorphism (SSD) in this species. LÄS MER