Search for dissertations about: "biological clock"

Showing result 1 - 5 of 38 swedish dissertations containing the words biological clock.

  2. 1. Genomic and morphological diversity of marine planktonic diatom-diazotroph associations : a continuum of integration and diversification through geological time

    Author : Andrea Caputo; Rachel Ann Foster; Monika Quinones Winder; Ramon Massana; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; phytoplankton; diatoms; cyanobacteria; diazotrophs; symbiosis; evolution; phylogenetics; confocal microscopy; qPCR; CARD-FISH; tropics; sub-tropics; Marine Ecology; marin ekologi;

    Abstract : Symbioses between eukaryotes and nitrogen (N2)-fixing cyanobacteria (or diazotrophs) are quite common in the plankton community. A few genera of diatoms (Bacillariophyceae) such as Rhizosolenia, Hemiaulus and Chaetoceros are well known to form symbioses with the heterocystous diazotrophic cyanobacteria Richelia intracellularis and Calothrix rhizosoleniae. READ MORE

  4. 2. Dating Divergence Times in Phylogenies

    Author : Cajsa Lisa Anderson; Kåre Bremer; Katleen M. Pryer; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; systematic biology; divergence time; nonprametric rate smoothing; Bayesian; multidivtime; eudicots; Neoaves; monocots; dating; molecular clock; relaxed clock; age constraint; fossil; calibration; PATHd8; penalized likelihood; Biology; Biologi;

    Abstract : This thesis concerns different aspects of dating divergence times in phylogenetic trees, using molecular data and multiple fossil age constraints.Datings of phylogenetically basal eudicots, monocots and modern birds (Neoaves) are presented. Large phylograms and multiple fossil constraints were used in all these studies. READ MORE

  5. 3. The circadian clock in annuals and perennials : coordination of Growth with Environmental Rhythms

    Author : Mikael Johansson; Maria E. Eriksson; Paul Devlin; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; circadian clock; arabidopsis; populus; Molecular biology; Molekylärbiologi; Plant biotechnology; Växtbioteknik; Plant physiology; Växtfysiologi; molekylärbiologi; Molecular Biology;

    Abstract : Since the first signs of life on planet earth, organisms have had to adapt to the daily changes between light and dark, and high and low temperatures. This has led to the evolution of an endogenous time keeper, known as the circadian clock. READ MORE

  6. 4. Molecular Evolution of the Vertebrate Genome

    Author : Kiwoong Nam; Hans Ellegren; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In this thesis, I studied molecular evolution of the vertebrate genome, focusing on sex chromosomes, protein coding genes, and genome size variation. The evolutionary history of avian sex chromosomes was analyzed by comparing substitution rate among 12 gametologous gene pairs on the Z and W chromosomes. READ MORE

  7. 5. Functional analyses of growth and development in the liverwort Marchantia polymorpha

    Author : Anja Billhardt; D. Magnus Eklund; Marcel Quint; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Land plant evolution; Bryophytes; Marchantia polymorpha; Dormancy; Circadian clock;

    Abstract : Land plants developed from a freshwater charophycean algae about 500 million years ago. Today, they consist of two main clades, the vascular plants and the non-vascular bryophytes including hornworts, liverworts and mosses. READ MORE