Sökning: "evolutionary changes"

Visar resultat 26 - 30 av 239 avhandlingar innehållade orden evolutionary changes.

  1. 26. A Unified Multitude : Experimental Studies of Bacterial Chromosome Organization

    Författare :Eva Garmendia; Diarmaid Hughes; Linus Sandegren; John R. Roth; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; bacterial evolution; chromosome organization and structure; chromosomal inversions; EF-Tu; horizontal gene transfer; Biologi med inriktning mot mikrobiologi; Biology with specialization in Microbiology;

    Sammanfattning : Bacteria are many, old and varied; different bacterial species have been evolving for millions of years and show many disparate life-styles and types of metabolism. Nevertheless, some of the characteristics regarding how bacteria organize their chromosomes are relatively conserved, suggesting that they might be both ancient and important, and that selective pressures inhibit their modification. LÄS MER

  2. 27. Genetic response to pollution in sticklebacks; natural selection in the wild

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

    Sammanfattning : 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. LÄS MER

  3. 28. Thriving in extremes : Local adaptation of grasses (Poaceae) to geothermally heated soils on a subarctic island

    Författare :Jan-Niklas Nuppenau; Aelys M. Humphreys; Catarina Rydin; Johan Ehrlén; Alessandro Chiarucci; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; abiotic stress; Agrostis; cold; colonization history; common garden; extreme environments; Festuca; frost; ice encasement; Iceland; heat; overwintering; phenology; plastome; snown; thermal tolerance; Plant Systematics; växtsystematik;

    Sammanfattning : Temperature is one of the most decisive parameters when it comes to determining characteristics and distributions of life worldwide. For plants, as sessile organisms, it is particularly important to be able to deal with the temperatures they are exposed to at a given location. LÄS MER

  4. 29. Life history evolution during a climate-driven butterfly range expansion

    Författare :Mats Ittonen; Karl Gotthard; Philipp Lehmann; Christopher Wheat; Sarah Diamond; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; climate change; diapause; genomics; insect cold tolerance; life cycle; local adaptation; parallel evolution; photoperiodism; reciprocal transplant; zoologisk ekologi; Animal Ecology;

    Sammanfattning : Climate change pushes species polewards and upwards – as temperatures rise, species move to areas that were previously too cold for them. During range expansions, species encounter unfamiliar environmental conditions, which may require evolutionary adaptation, but expanding populations may often be hampered by their genetic and demographic properties. LÄS MER

  5. 30. Haploid selection in animals : Exploring the fitness consequences and underlying mechanisms

    Författare :Ghazal Alavioon; Simone Immler; Tommaso Pizzari; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; sperm; evolution; haploid selection; reproductive aging; fitness;

    Sammanfattning : A consequence of sexual reproduction in eukaryotes is the evolution of a biphasic life cycle with alternating diploid and haploid gametic phases. While our focus in evolutionary biology is on selection during the diploid phase, we know relatively little about selection occurring during the haploid gametic stage. LÄS MER