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Showing result 1 - 5 of 11 swedish dissertations matching the above criteria.

  2. 1. Effects of Agriculture on Abundance, Genetic Diversity and Fitness in the Common Frog, Rana temporaria

    Author : Markus Johansson; Anssi Laurila; Juha Merilä; Craig R. Primmer; Michael W. Bruford; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Biology; agriculture; agrochemicals; amphibians; effective population size; genetic diversity; genetic structure; hierarchical sampling; microsatellites; Rana temporaria; Biologi; Biology; Biologi;

    Abstract : The aims of this thesis were to evaluate the effects of agriculture on amphibians in terms of (i) population genetic consequences of agriculture-induced spatial changes of the landscape and (ii) local adaptation and tolerance to frequently used agrochemicals. The study was performed using the common frog Rana temporaria as a model. READ MORE

  4. 2. Evolutionary ecology of ultraviolet-B radiation stress tolerance in amphibians

    Author : Maarit Pahkala; Trevor Beebee; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; amphibians; anomalies; embryonic development; geographic variation; growth; Rana arvalis; Rana temporaria; survival; UV-B radiation; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; populationsbiologi; Population Biology;

    Abstract : During the last decades many amphibian species and populations have experienced declines and extinctions in different parts of the world. Anthropogenic activities are believed to account for these declines, and one of the hypothesized causes has been the increased level of ultraviolet-B (UV-B) radiation due to depletion of the stratospheric ozone layer. READ MORE

  5. 3. Adaptation Along Environmental Gradients: an Evaluation of Physiological Mechanisms and Ecological Constraints

    Author : Beatrice Lindgren; Anssi Laurila; Jacob Höglund; Svante Winberg; Andrew Sih; Uppsala universitet; []
    Keywords : Biology; Rana temporaria; latitudinal clines; growth rate; growth efficiency; SMR; predation; competition; trade-off; Biologi;

    Abstract : For ectotherms living in seasonal environments, time available for development and growth is often constrained by the length of the growth season. Declining season length towards higher latitudes often select for latitudinal clines in development and growth rates, exhibiting increasing growth and developmental rates towards the north. READ MORE

  6. 4. Endocrine Disruption in Amphibians : Developmental Effects of Ethynylestradiol and Clotrimazole on the Reproductive System

    Author : Irina Gyllenhammar; Cecilia Berg; Ingvar Brandt; Lena Holm; Joakim Larsson; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Test system; Xenopus tropicalis; Rana temporaria; sex ratio; sex differentiation; fertility; aromatase; ovary; testis; oviduct; Biology; Biologi;

    Abstract : Amphibian populations are declining world-wide and one of the suggested reasons is environmental pollutants. Studies of long-term effects on the reproductive system in frogs following larval exposure to environmental pollutants are scarce. It is therefore important to develop methods to study developmental reproductive toxicity in amphibians. READ MORE

  7. 5. Phenotypic plasticity and local adaptation in island populations of Rana temporaria

    Author : Martin Lind; Frank Johansson; Juha Merilä; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Costs of plasticity; Developmental threshold; FST; Local adaptation; Phenotypic plasticity; Pool drying; QST; Freshwater ecology; Limnisk ekologi; zooekologi; Animal Ecology;

    Abstract : Phenotypic plasticity is the ability of a genotype to express different phenotypes in different environments. Despite its common occurrence, few have investigated differences in plasticity between populations, the selection pressures responsible for it, and costs and constraints associated with it. READ MORE