Sökning: "Tristan da Cunha"

Hittade 2 avhandlingar innehållade orden Tristan da Cunha.

  1. 1. Holocene climate and environmental dynamics on the Tristan da Cunha island group, South Atlantic

    Författare :Karl Ljung; Kvartärgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; palynologi; Geology; climate change; pollen analysis; Palaeobotany; phylogeny; palynology; Paleobotanik; fylogeni; vegetation change; gyttja; peat; Holocene; Quaternary; South Atlantic; Tristan da Cunha; physical geography; Geologi; fysisk geografi;

    Sammanfattning : It has been shown that the present interglacial has been climatically dynamic with both rapid and severe climatic fluctuations. The spatial and temporal differences of these changes are however not fully resolved. The aim of this thesis is to present a detail high resolution record of past climate changes from the central South Atlantic. LÄS MER

  3. 2. On Speciation in Birds – Genomic Signatures across Space and Time

    Författare :Martin Stervander; MEMEG; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; colonization; islands; isolation; introgressive hybridization; sympatry; natural selection; bill morphology; coalescence-based analyses; DNA sequencing; birds; divergence; Speciation;

    Sammanfattning : The process of speciation is a cornerstone in evolutionary biology. In Darwin’s On the Origin of Species, he described how he imagined that a new species would evolve to fill an empty niche. This focus on ecology shifted with Mayr towards the importance of isolation, and for many decades the geographic modes of speciation were debated. LÄS MER