Sökning: "selection gradients"

Visar resultat 1 - 5 av 25 avhandlingar innehållade orden selection gradients.

  1. 1. Plant-Animal Interactions and Evolution of Floral Display and Flowering Phenology in Arabidopsis lyrata

    Författare :Saskia Sandring; Jon Ågren; Johan Ehrlén; José Gómez; Uppsala universitet; []
    Nyckelord :Ecology; Arabidopsis lyrata; natural selection; floral display; phenology; flowering time; plant-animal interactions; pollination; herbivory; selection gradients; population differentiation; local adaptation; Ekologi;

    Sammanfattning : In this thesis, I combined comparative and experimental approaches to examine selection on reproductive traits, and population differentiation in the insect-pollinated, outcrossing, perennial herb Arabidopsis lyrata. More specifically, I (1) determined whether selection on flowering phenology and floral display can be attributed to interactions with pollinators and herbivores, (2) examined whether population differentiation in flowering phenology and floral display is correlated with current selection on these traits, and (3) tested for local adaptation from contrasting environments in Europe. LÄS MER

  3. 2. Population divergence at different spatial scales in a wide-spread amphibian

    Författare :Patrik Rödin Mörch; Anssi Laurila; Jacob Höglund; Bengt Hansson; Uppsala universitet; []
    Nyckelord :Adaptive divergence; environmental gradients; genomics; life-history; amphibians; Biologi med inriktning mot zooekologi; Biology with specialization in Animal Ecology;

    Sammanfattning : To study the distribution of genetic and phenotypic variation in different environments and at different spatial scales is important in order to understand the process of local adaptation and how populations will respond to future climate change. In my thesis I study populations of moor frogs (Rana arvalis) at different spatial scales, first along a 1700 km latitudinal gradient (Paper I, II, IV) and, second, in a system of inter-connected wetlands (III, IV). LÄS MER

  4. 3. Population differentiation in Lythrum salicaria along a latitudinal gradient

    Författare :Katarina Olsson; Jon Ågren; Susan Kalisz; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; additive genetic variance; clinal variation; evolutionary constraints; G matrix; genetic correlation; natural selection; pollen limitation; population differentiation; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : In this thesis, quantitative genetic approaches, common-garden experiments, and field studies were combined to examine patterns of population differentiation and the genetic architecture of characters of putative adaptive significance in the widely distributed perennial herb Lythrum salicaria. In this work, I (1) documented patterns of population differentiation in phenology, life-history, and morphology along latitudinal gradients at different geographical scales, (2) investigated the genetic architecture of phenology, flower morphology, and inflorescence size, and (3) combined estimates of phenotypic selection in the field with information on the genetic variance-covariance matrix (G) to examine potential constraints to adaptive evolution. LÄS MER

  5. 4. Modelling the Evolution of Species’ Ranges

    Författare :Martin Eriksson; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Range expansions; Range margins; Population genetics; Evolutionary biology; Local adaptation; Environmental selection; Phenotypic plasticity; Computer simulations;

    Sammanfattning : The fact that species have limited ranges is often due to a limited ability to adapt to the environmental conditions that occur outside their geographic ranges. However, due to ongoing climate change, the environmental conditions within species’ geographic ranges may change in the near-future. LÄS MER

  7. 5. Sexual conflict and male-female coevolution in the fruit fly

    Författare :Urban Friberg; Göran Arnqvist; Daniel Promislow; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cryptic male mate choice; Drosophila melanogaster; female mate choice; multiple mating; sexual conflict; sexually antagonistic coevolution; sexual selection; speciation; sperm competition; Biology; Biologi;

    Sammanfattning : Harmony and cooperation was for long believed to dominate sexual interactions. This view slowly started to change 25 years ago and is today replaced with a view where males and females act based on what is best from a costs-benefits perspective. LÄS MER