Search for dissertations about: "divergent selection"

Showing result 1 - 5 of 53 swedish dissertations containing the words divergent selection.

2. 1. Evolutionary Ecology of Floral Traits in Fragrant Orchids

   Author : Elodie Chapurlat; Nina Sletvold; Jon Ågren; Magne Friberg; Kathleen Kay; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; agents of selection; diurnal and nocturnal pollination; divergent selection; field experiment; floral evolution; floral scent; Gymnadenia conopsea; Gymnadenia densiflora; Orchidaceae; phenotypic selection; pollinator-mediated selection; spatial variation; scent rhythm;

   Abstract : Why are flowers so diverse? Much of floral evolution is thought to be driven by pollinator-mediated selection. However, the connection between macroevolutionary patterns of floral diversity and microevolutionary processes remains poorly understood. In this thesis, I have used the fragrant orchids Gymnadenia conopsea s.s. READ MORE

4. 2. Evolution of Spur Length in a Moth-pollinated Orchid

   Author : Elin Boberg; Jon Ågren; W. Scott Armbruster; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Platanthera bifolia; floral evolution; natural selection; pollination; spur length; population differentiation; divergent selection; disruptive selection; reproductive isolation; Biology; Biologi; Ecological Botany; Ekologisk botanik;

   Abstract : There is considerable evidence that pollinator shifts can explain many differences in flower morphology between closely related plant species, but the extent to which pollinator shifts can explain the maintenance of among-population variation in floral traits within species is poorly known. In this thesis, I combined comparative and experimental approaches to examine the evolution of floral traits in the moth-pollinated orchid Platanthera bifolia. READ MORE

5. 3. Genetic response to pollution in sticklebacks; natural selection in the wild

   Author : Emma Lind; Mats Grahn; Marjorie Oleksiak; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Population genomics; genome scan; divergent selection; Gasterosteus aculeatus; Baltic Sea; pollution; funktionell zoomorfologi; Functional Zoomorphology;

   Abstract : The last century, humans have been altering almost all natural environments at an accelerating rate, including the Baltic Sea that has highly eutrophicated areas and many coastal industries such as Pulp-mills. For animals living in a habitat that changes there are basically two alternatives, either to cope with the change or become locally extinct. READ MORE

6. 4. The Interplay Between Selection And Constraints On Adaptive Divergence And Phenotypic Evolution

   Author : Fabrice Eroukhmanoff; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Selection; Constraints; Adaptive Divergence; G-matrix; Gene Flow.; Speciation;

   Abstract : Under natural or sexual selection, individuals with advantageous traits or combinations of traits will be more successful than their peers at surviving and/or reproducing. Provided these traits are heritable, meaning that they have a genetic basis, the traits combinations which are selected for, will increase in frequency in the population. READ MORE

7. 5. Migratory behaviour and adaptive divergence in life-history traits of pike (Esox lucius)

   Author : Petter Tibblin; Per Larsson; Anders Forsman; Asbjørn Vøllestad; Linnéuniversitetet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; conservation; evolution; homing; local adaptation; management; phenotypic variation; population divergence; selection; sympatric;

   Abstract : Population divergence shaped by natural selection is central to evolutionary ecology research and has been in focus since Darwin formulated “The origin of species”. Still, the process of adaptive divergence among sympatric populations is poorly understood. READ MORE