Search for dissertations about: "extinction rates"

Showing result 1 - 5 of 47 swedish dissertations containing the words extinction rates.

  2. 1. The tempo and mode of evolution : a neontological reappraisal

    Author : Melanie Monroe; Folmer Bokma; Pär Ingvarsson; Mikael Fortelius; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; birds; extinction; macroevolution; mammals; microevolution; punctuated equilibrium; speciation;

    Abstract : The theory of “punctuated equilibrium” suggests that species evolve rapidly during or immediately upon speciation, “punctuating” long periods of little or no morphological evolution. Here I confirm that body size differences within clades of birds and mammals are best explained using a model of punctuated evolution. READ MORE

  4. 2. Species extinctions in food webs : local and regional processes

    Author : Anna Eklöf; Bo Ebenman; Peter Münger; Marcel Holyoak; Linköpings universitet; []
    Keywords : Extinction; food web; metacommunity; dispersal; species loss; migration; habitat fragmentation; connectance; NATURAL SCIENCES; NATURVETENSKAP;

    Abstract : Loss of biodiversity is one of the most severe threats to the ecosystems of the world. The major causes behind the high population and species extinction rates are anthropogenic activities such as overharvesting of natural populations, pollution, climate change and destruction and fragmentation of natural habitats. READ MORE

  5. 3. Insect Diversity in Changing Landscapes

    Author : Markus Franzén; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; växtparasitologi; Entomologi; plant parasitology; Zoology; Zoologi; Entomology; Ekologi; Ecology; butterfly; bee; dispersal; extinction; Djurekologi; Animal ecology;

    Abstract : During recent decades, concern about the loss of biodiversity has increased. To change this negative trend there is an urgent need for effective conservation measures and there are ample evidence that conservation of organisms without an understanding of their ecology and behaviour is impossible. READ MORE

  6. 4. Transient Phenomena in CO and Hydrocarbon Oxidation over Supported Platinum Catalysts

    Author : Per-Anders Carlsson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; mean-field kinetics simulations; ignition; environmental heterogeneous catalysis; flow-reactor studies; periodic operation; extinction; low-temperature activity; transient methods; in situ spectroscopy;

    Abstract : The aim with this thesis work was to better understand transient phenomena involved in the low-temperature oxidation of CO and hydrocarbons by oxygen over typical oxidation catalysts. Supported platinum catalysts were prepared and carefully studied under transient conditions by means of flow-reactor experiments, different in situ spectroscopic (FTIR and XANES) methods in combination with mass spectrometry and mean-field kinetics simulations. READ MORE

  7. 5. Advancing Evolutionary Biology: Genomics, Bayesian Statistics, and Machine Learning

    Author : Tobias Andermann; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; computational biology; bioinformatics; phylogenetics; neural networks; NGS; target capture; Illumina sequencing; fossils; IUCN conservation status; extinction rates;

    Abstract : During the recent decades the field of evolutionary biology has entered the era of big data, which has transformed the field into an increasingly computational discipline. In this thesis I present novel computational method developments, including their application in empirical case studies. READ MORE