Search for dissertations about: "character evolution"

Showing result 1 - 5 of 93 swedish dissertations containing the words character evolution.

2. 1. Evolution and biodiversity of the Ixoroideae (Rubiaceae)

   Author : Kent Kainulainen; Birgitta Bremer; Sylvain Razafimandimbison; Torsten Eriksson; Sandra Knapp; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Alberteae; character evolution; classification; Condamineeae; fruit evolution; Ixoroideae; phylogenetics; pollen presentation; Rubiaceae; systematics; taxonomy; Systematics and phylogenetics; Systematik och fylogeni; växtsystematik; Plant Systematics;

   Abstract : The phylogenetic relationships within subfamily Ixoroideae of the coffee family are investigated by phylogenetic reconstruction of molecular data, including regions of the chloroplast DNA (matK, ndhF, rbcL, rps16, trnH-psbA, trnS-G, and trnT-F), and the nuclear ribosomal DNA (ITS). The evolution of morphological characters within the group are inferred, with focus on characters used in classification. READ MORE

4. 2. Origin and the evolution of diatoms through the integration of paleontology and phylogenetics

   Author : Karolina Brylka; Berggrundsgeologi; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; diatoms; evolution; fossil record; Cretaceous; molecular evolution; Mesozoic; silicon transporter proteins; gene duplication;

   Abstract : Diatoms, the prominent photosynthetic eucaryotes, have inhabited the world’s oceans for at least the past 120 Ma since their first appearance in the Lower Cretaceous. There are also records of older diatoms, from the Jurassic dating to ca. 172 Ma and ca. 165 Ma, however these are poorly documented. READ MORE

5. 3. Comparative morphological studies of fossil and living plane trees (Platanaceae) and oaks (Quercus): taxonomy, ecology, evolution

   Author : Georg Florian Tschan; Thomas Denk; Ove Eriksson; Bertil Ståhl; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Platanaceae; Platanus; Credneria; Quercus; Galliferae; leaf architecture; epidermal anatomy; comparative morphology; character variation; variability; sample size; diversity patterns; species concepts; ecology; biogeography; evolution; plant fossils; Plant Ecology; växtekologi;

   Abstract : Morphological characters are essential for flowering plant identification, but also provide information about diversity patterns and ecological adaptation. In woody plant species, characters of the leaf are among the most useful and can be examined on fossils as well. READ MORE

6. 4. Ecology and Evolution of Resistance to Herbivory : Trichome Production in Arabidopsis lyrata

   Author : Geir Løe; Jon Ågren; Kari Lehtilä; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Biology; Plant-animal interactions; herbivory; trichomes; plant resistance; plant defense; divergent selection; local adaptation; GLABROUS1; evolution; matrix population models; LTRE; Biologi; Biology; Biologi;

   Abstract : In this thesis, I examine variation in occurrence and performance of glabrous and trichome-producing plants of the perennial herb Arabidopsis lyrata. I combine field studies and genetic analysis to (1) examine the function of trichomes as a resistance character in natural populations, (2) compare the magnitude of population differentiation in trichome-production and at putatively neutral marker loci, (3) examine the molecular genetic basis of trichome-production, and (4) quantify the effects of herbivore removal on population growth and relative performance of glabrous and trichome-producing plants. READ MORE

7. 5. Selection and Floral Evolution in Platanthera bifolia and P. chlorantha (Orchidaceae)

   Author : Johanne Maad; Charles B. Fenster; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; Evolution; phenotypic selection; male function hypothesis; mating systems; floral shifts; orchids; pollination; moth pollinators; Platanthera.; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; systematisk botanik; Systematic Botany;

   Abstract : Natural selection mediated by pollinators has influenced the evolution of floral diversity of the flowering plants (angiosperms). The scope of this thesis was to study: 1) phenotypic selection, 2) mating systems, and 3) floral shifts involved in plant speciation. Model plant species were Platanthera bifolia and P. chlorantha (Orchidaceae). READ MORE