Search for dissertations about: "Historical geology and palaeontology"
Showing result 1 - 5 of 16 swedish dissertations containing the words Historical geology and palaeontology.
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1. The morphology and evolutionary significance of the anomalocaridids
Abstract : Approximately 600 to 500 million years ago, a major evolutionary radiation called the “Cambrian Explosion” gave rise to nearly all of the major animal phyla known today. This radiation is recorded by various fossil lagerstätten, such as the Burgess Shale in Canada, where soft-bodied animals are preserved in exquisite detail. READ MORE
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2. Origin and Lifestyles of early Brachiopods and other Lophotrochozoans : Insights from the Chengjiang and Guanshan Fossil-Lagerstätten
Abstract : One of the great unsolved evolutionary questions concerns the origin and phylogeny of the major animal phyla that appeared in the fossil record more than 540 million years ago, during the Cambrian explosion. Although new molecular information has been very useful, we still have little understanding about the origin of most of the phyla of bilaterians living today. READ MORE
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3. Evolution and taxonomy of Cambrian arthropods from Greenland and Sweden
Abstract : Arthropods have a rich fossil record spanning the Phanerozoic. Biomineralized forms such as the extinct trilobites are particularly common and are proven index fossils for biostratigraphy. Forms with an unmineralized cuticle are more rare, preserved only in so called konservat lagerstätten. READ MORE
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4. Exceptionally Preserved Cambrian Lophotrochozoa : Taxonomy, Systematics and Taphonomy of Chengjiang and Indian Springs Lophophorates
Abstract : The origin and evolution of Lophotrochozoa can be traced to the plethora of lower Cambrian scleritome taxa. We aim to determine the character suites linking these stem-Lophotrochozoa to their extant crown relatives, in particular the small shelly tommotiids and the stem-group brachiopods. READ MORE
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5. Early Cambrian Problematic Lophotrochozoans and Dilemmas of Scleritome Reconstructions
Abstract : The emergence and radiation of metazoan body plans around the Precambrian/Cambrian boundary, some 500-600 million years ago, seems to be concordant with the appearance and diversification of preservable hard parts. Several Precambrian soft-bodied, multicellular organisms most likely represent stem-group bilaterians, but their fossil record is rather sparse. READ MORE