Sökning: "latitudinal variation"
Visar resultat 1 - 5 av 30 avhandlingar innehållade orden latitudinal variation.
1. Natural variation in cold adaptation and freezing tolerance in Arabidopsis thaliana
Sammanfattning : Plants have spread to almost everywhere in the world. As they disperse, they meet many different environments to which they may be able to adapt. For a plant species to adapt to a new environment, genetic variation is needed. The individuals differ from each other in their genetic composition, which often means differences in phenotypes. LÄS MER
2. Population differentiation in Lythrum salicaria along a latitudinal gradient
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
3. Immunogenetic variation along the latitudinal gradient in Scandinavian anuran species : Evolutionary processes, demography and infection
Sammanfattning : The evolutionary and demographic processes affecting how genetic variation is partitioned and distributed over large geographical scales is of fundamental importance for our understanding of how organisms may adapt to their environments. Northern peripheral populations generally have lower genetic variation and individuals in these populations may therefore face difficulties adapting to their local environment. LÄS MER
4. Studies on Natural Variation and Evolution of Photoperiodism in Plants
Sammanfattning : Photoperiodism refers to the organism’s ability to detect and respond to seasonal changes in the daily duration of light and dark and thus constitutes one of the most significant and complex examples of the interaction between the organism and its environment. This thesis attempts to describe the prevalence of variation in a photoperiodic response, its adaptive value, and its putative genetic basis in a common cruciferous weed, Capsella bursa-pastoris (Brassicaceae). LÄS MER
5. Effects of climate on phenological synchrony between butterflies and their host plants
Sammanfattning : Shifts in species’ phenologies and phenological asynchronies between the interacting organisms have received a lot of attention in the context of climate change. Changes in temporal overlap between species, caused by phenological asynchrony, make species depending on one another become so separated in time that they can no longer interact. LÄS MER
