Search for dissertations about: "Sharks"
Showing result 1 - 5 of 12 swedish dissertations containing the word Sharks.
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1. 100 million years of shark macroevolution : A morphometric dive into tooth shape diversity
Abstract : Few vertebrate clades exhibit the evolutionary longevity and versatility of sharks, which constitute nearly half of all current chondrichthyan biodiversity and represent an ecological diversity of mid-to-apex trophic-level predators in both marine and freshwater environments. The rich fossil record of shark teeth from Mesozoic and Cenozoic rocks also makes the group amenable to large-scale quantitative analyses. READ MORE
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2. Jurassic and Early Cretaceous selachians - focus on southern Scandinavia
Abstract : The Jurassic and Early Cretaceous selachian faunas of Scania (Skåne), southern Sweden and the island of Bornholm (Denmark) have been investigated. Three Early Jurassic shark tooth assemblages have been recorded and investigated, one from Hettangian strata and the other two from Pliensbachian sediments. READ MORE
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3. Organohalogen contaminants in Greenland shark (Somniosus microcephalus)
Abstract : The remote sub-Arctic/Arctic environment has due to human activities become a sink for organohalogen contaminants (OHCs). These OHC include traditional contaminants such as polychlorinated biphenyls (PCBs), DDTs and technical mixtures of polybrominated diphenyl ethers (PBDEs), all included in the Stockholm Convention list of persistent organic pollutants (POPs). READ MORE
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4. Evolution of Vertebrate Eyes: a study on lens suspension and optical proterties
Abstract : Many fishes have well-developed visual systems with color vision capabilities. The crystalline lens is the major refractive element in a fish eye since the cornea is optically inactive underwater. A typical fish eye has a large pupil and a lens of short focal length, features that increase light gathering ability. READ MORE
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5. Endocranial Morphology and Phylogeny of Palaeozoic Gnathostomes (Jawed Vertebrates)
Abstract : Gnathostomes, or jawed vertebrates, make up the overwhelming majority of modern vertebrate diversity. Among living vertebrates, they comprise the chondrichthyans (“cartilaginous fishes” such as sharks, skates, rays, chimaeras) and the osteichthyans (“bony fishes” or bony vertebrates, inclusive of tetrapods). READ MORE