Sökning: "taxon"

Visar resultat 36 - 40 av 63 avhandlingar innehållade ordet taxon.

1. 36. Mistletoes and Thionins : as Selection Models in Natural Products Drug Discovery

   Författare :Sonny Larsson; Anders Backlund; Lars Bohlin; Peter J. Houghton; Uppsala universitet; []
   Nyckelord :Pharmacognosy; drug discovery; mistletoe; phylogeny; cytotoxic peptides; Santalales; Farmakognosi;

   Sammanfattning : The process of drug discovery from natural products starts with the selection of study object. In this project recent knowledge and methods are incorporated to investigate the process of such selection for pharmacognostic investigations. LÄS MER

3. 37. Molecular phylogeny of tyrant flycatchers, cotingas, manakins and their allies (Aves: Tyrannida)

   Författare :Jan I. Ohlson; Per G. P. Ericson; Cristina Y. Miyaki; Stockholms universitet; []
   Nyckelord :Suboscines; Tyrannida; Tyrannidae; Cotingidae; Pipridae; South America; phylogeny; evolution; adaptive radiation; NATURAL SCIENCES; NATURVETENSKAP; Systematic Zoology; zoologisk systematik och evolutionsforskning;

   Sammanfattning : Tyrannida is a monophyletic clade that together with Furnariida constitutes the New World suboscines. The ca 560 species in Tyrannida are traditionally divided between three families: Tyrannidae (tyrant flycatchers), Cotingidae (cotingas) and Pipridae (manakins). LÄS MER

4. 38. Controversies over taxonomic and nomenclatural instability: an empirical approach

   Författare :George Sangster; Per Ericson; Mikael Thollesson; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systematic Zoology; zoologisk systematik och evolutionsforskning;

   Sammanfattning : Taxonomic names serve two important functions: they reflect hypotheses about the existence of taxa, and they serve as the primary means to communicate about biodiversity. The dual purpose of names is a source of conflict and misunderstanding among taxonomists and end-users of taxonomy. LÄS MER

5. 39. Vegetation and climate during Weichselian ice free intervals in northern Sweden : Interpretations from fossil and modern pollen records

   Författare :Martina Hättestrand; Ann-Marie Robertsson; Donatella Magri; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Weichselian; interstadial; stadial; glacial history; northern Sweden; Tärendö; Riipiharju; Rissejauratj; Veiki moraine; pollen analysis; pollen deposition; pollen trap; PAR; Quaternary geology; Kvartärgeologi;

   Sammanfattning : In this thesis the Weichselian history of northern Sweden is investigated, with emphasis on vegetation and climate during ice-free intervals. The main method used has been pollen analysis of sediments from pre-Late Weichselian landforms. To interpret fossil pollen assemblages, comparisons with modern pollen spectra were made. LÄS MER

7. 40. Silurian vertebrates of Gotland (Sweden) and the Baltic Basin

   Författare :Oskar Bremer; Henning Blom; Per E. Ahlberg; Tiiu Märss; Héctor Botella; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; early vertebrates; vertebrate microremains; scale taxonomy; early vertebrate distribution; environmental preferences; Silurian; Baltic Basin; Gotland; Sweden; Biology with specialization in Evolutionary Organismal Biology; Biologi med inriktning mot evolutionär organismbiologi;

   Sammanfattning : During the Silurian, the Swedish island Gotland was positioned close to the equator and covered by a shallow sea called the Baltic Basin. The sedimentary rocks (predominantly carbonates) comprising most of the island today were initially formed in this warm sea, and the relatively complete succession of rocks often contains fossil fragments and scales from early vertebrates, including heterostracans, anaspids, thelodonts, osteostracans, acanthodians, and a stem-osteichthyan. LÄS MER