2 resultados para biologiska mångfalden

em Academic Archive On-line (Stockholm University


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Conservatism is a central theme of organismic evolution. Related species share characteristics due to their common ancestry. Some concern have been raised among evolutionary biologists, whether such conservatism is an expression of natural selection or of a constrained ability to adapt. This thesis explores adaptations and constraints within the plant reproductive phase, particularly in relation to the evolution of fleshy fruit types (berries, drupes, etc.) and the seasonal timing of flowering and fruiting. The different studies were arranged along a hierarchy of scale, with general data sets sampled among seed plants at the global scale, through more specific analyses of character evolution within the genus Rhamnus s.l. L. (Rhamnaceae), to descriptive and experimental field studies in a local population of Frangula alnus (Rhamnaceae). Apart from the field study, this thesis is mainly based on comparative methods explicitly incorporating phylogenetic relationships. The comparative study of Rhamnus s.l. species included the reconstruction of phylogenetic hypotheses based on DNA sequences. Among geographically overlapping sister clades, biotic pollination was not correlated with higher species richness when compared to wind pollinated plants. Among woody plants, clades characterized by fleshy fruit types were more species rich than their dry-fruited sister clades, suggesting that the fleshy fruit is a key innovation in woody habitats. Moreover, evolution of fleshy fruits was correlated with a change to more closed (darker) habitats. An independent contrast study within Rhamnus s.l. documented allometric relations between plant and fruit size. As a phylogenetic constraint, allometric effects must be considered weak or non-existent, though, as they did not prevail among different subclades within Rhamnus s.l. Fruit size was correlated with seed size and seed number in F. alnus. This thesis suggests that frugivore selection on fleshy fruit may be important by constraining the upper limits of fruit size, when a plant lineage is colonizing (darker) habitats where larger seed size is adaptive. Phenological correlations with fruit set, dispersal, and seed size in F. alnus, suggested that the evolution of reproductive phenology is constrained by trade-offs and partial interdependences between flowering, fruiting, dispersal, and recruitment phases. Phylogenetic constraints on the evolution of phenology were indicated by a lack of correlation between flowering time and seasonal length within Rhamnus cathartica and F. alnus, respectively. On the other hand, flowering time was correlated with seasonal length among Rhamnus s.l. species. Phenological differences between biotically and wind pollinated angiosperms also suggested adaptive change in reproductive phenology.

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Studien undersöker hur kvinnliga karaktärer representeras i relation till skräcktematiken i tv-serien Penny Dreadful (2014-). Syftet har varit att studera huruvida det som är typiska kännetecken för skräck kan kopplas till kvinnlighet, femininitet och feminism (det senare då man kan uppfatta ett genuskritiskt samtal i serien). Med hjälp av psykoanalytiska teorier kring abjektion visar analysen hur det som är skrämmande med kvinnor, är skrämmande på andra sätt än vad som är skrämmande med män. Det som är abjekt med kvinnan definieras ofta utifrån hennes sexualitet och biologiska egenskaper, och skapar därmed en feminin monstrositet och således är helt olik den manliga. Detta har till stor del växt fram genom historiska myter, religioner och konst, som har bidragit till könsspecifika monster utifrån stereotyp femininitet, så som häxor, sirener eller Medusa. Genom att utforska tv-seriens karaktärer med hjälp av semiotiska och psykoanalytiska verktyg avslöjas möjliga tolkningar som visar hur nämnda feminina monster tycks grunda sig i manlig rädsla och kvinnan som hot. Kastrationskomplexet som bidragande faktor och den manliga blicken tycks därför kväsa uttryck för kvinnlig frigörelse i serien, genom att sexualisera, plåga och göra kvinnan abjekt och monstruös i direkt genmäle till dessa. Serien tycks därför trots sin genuskritiska diskurs kontrolleras av en manlig blick och ett skoptofiliskt seende, något som möjligtvis bidrar till att kvinnlighet och femininitet kodas som abjekt, och i värsta fall stigmatiserar den feministiska kvinnan.