Search for dissertations about: "Among-population variation"

Showing result 1 - 5 of 10 swedish dissertations containing the words Among-population variation.

2. 1. Pollinator-mediated selection and the evolution of floral traits in orchids

   Author : Judith Trunschke; Jon Ågren; Nina Sletvold; Allan G. Ellis; Uppsala universitet; []
   Keywords : Among-population variation; Ecotype; Field experiment; Floral evolution; Germination; Local adaptation; Orchidaceae; Platanthera bifolia; Phenotypic selection; Pollination; Reciprocal transplant; Trait manipulation; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

   Abstract : In this thesis, I combined manipulations of traits and pollination environment with analysis of phenotypic selection to examine causes of variation in strength and mode of selection on floral traits, and I conducted a reciprocal sowing experiment to test for local adaptation in germination success. I tested the following predictions (1) the opportunity for selection, and the strength of pollinator-mediated and net selection increase with increasing pollen limitation, (2) the effects of traits affecting pollinator attraction and traits affecting pollination efficiency are non-additive and this leads to pollinator-mediated correlational selection, (3) the effects of spur length on pollen removal, pollen receipt, and female fitness differ between populations with short-tongued and populations with long-tongued pollinators, and (4) local adaptation at the stage of germination contributes to the maintenance of ecotypes growing in grasslands and woodlands, respectively. READ MORE

4. 2. Context dependency of plant – animal interactions

   Author : Malin A. E. König; Johan Ehrlén; Christer Wiklund; John Stinchcombe; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Anthocharis cardamines; attack intensity; Cardamine pratensis; cytotype; herbivory; larval fitness; oviposition; phenology; plant-animal interactions; plant resistance; plant tolerance; polyploidy; spatial variation; trait variation; Plant Ecology; växtekologi;

   Abstract : The strength and direction of interactions between organisms vary spatially across the landscape. Traditionally, the focus has been on how trait variation affects the interactions between species. However, differences in abiotic and biotic environmental factors may also alter the distribution, phenology and behavior of the interacting species. READ MORE

5. 3. Local Adaptation, Countergradient Variation and Ecological Genetics of Life-history Traits in Rana Temporaria

   Author : Ane Timenes Laugen; Wolf Blanckenhorn; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ecology; amphibians; Bergmanns rule; body size clines; countergradient variation; developmental rate; FST; temperature; QST; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; populationsbiologi; Population Biology;

   Abstract : The main aim of this work was to identify local adaptation processes in amphibian populations, thereby improving the general understanding of genetics and mechanisms behind the evolution and maintenance of biological diversity. Phenotypic and genetic variation in life-history traits was studied within and between populations common frog (Rana temporaria) populations along a 1600 km transect from southern Sweden to northern Finland. READ MORE

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

   Author : Katarina Olsson; Jon Ågren; Susan Kalisz; Umeå universitet; []
   Keywords : 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;

   Abstract : 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. READ MORE

7. 5. Genetic Variation and Evolution of Floral Display in Primula farinosa

   Author : Camille Madec; Jon Ågren; Johan Ehrlén; Richard Ennos; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; natural selection; flowering time; population differentiation; local adaptation; male reproductive success;

   Abstract : In this thesis, I combine molecular analyses, common-garden and field experiments to examine how evolutionary and ecological processes influence patterns of genetic variation among and within populations of the declining, insect-pollinated, self-incompatible, perennial herb Primula farinosa. More specifically I examined 1) whether genetic diversity at neutral marker loci was related to habitat fragmentation and habitat stability, 2) whether floral display and flowering time were more strongly differentiated among populations than were putatively neutral marker loci, 3) whether adaptive population differentiation could be detected on a local spatial scale, and 4) whether floral display differentially affected male and female reproductive success. READ MORE