Search for dissertations about: "Macroevolution"

Found 5 swedish dissertations containing the word Macroevolution.

2. 1. 100 million years of shark macroevolution : A morphometric dive into tooth shape diversity

   Author : Mohamad Bazzi; Per Ahlberg; Matt Friedman; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Sharks; Macroevolution; Extinction recovery dynamics; Geometric Morphometrics; Morphospace-Disparity Framework; Teeth; Biology with specialization in Evolutionary Organismal Biology; Biologi med inriktning mot evolutionär organismbiologi;

   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

4. 2. Stochastic Models in Phylogenetic Comparative Methods: Analytical Properties and Parameter Estimation

   Author : Krzysztof Bartoszek; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Adaptation; Adaptation; Birth-death process; Branching diffusion; Brownian motions; Conditioned branching process; Evolution; General Linear Model; Hybridization; Macroevolution; Measurement error; Multivariate phylogenetic comparative method; Optimality; Ornstein-Uhlenbeck process; Phyletic gradualism; Phylogenetic inertia; Phylogenetic uncertainty; Punctuated equilibrium; Yule tree; Macroevolution;

   Abstract : Phylogenetic comparative methods are well established tools for using inter-species variation to analyse phenotypic evolution and adaptation. They are generally hampered, however, by predominantly univariate approaches and failure to include uncertainty and measurement error in the phylogeny as well as the measured traits. READ MORE

5. 3. 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

6. 4. Phylogeny and macroevolution in Isoetes (Isoetales)

   Author : Eva Larsén; Catarina Rydin; Niklas Wikström; Ove Eriksson; Richard Bateman; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Bayesian inference; biogeography; Cenozoic; genomic data; fossil calibration; Isoetes; Isoetales; megaspore morphology; Mesozoic; molecular clocks; node ages; phylogeny; rhizomorphic lycopsids; scanning electron microscopy; Plant Systematics; växtsystematik;

   Abstract : This thesis has focused on the evolutionary history of Isoetes (Isoetales, Lycopsida), its phylogeny, megaspore morphology and evolutionary path through deep time. With a broadened sampling of species to include more of the worldwide diversity of the genus compared to previous work an unexpected sister to the rest of the genus was found. READ MORE

7. 5. Unlocking the hidden diversity of organic-walled microfossils from the early Cambrian of North Greenland

   Author : Elise Wallet; Sebastian Willman; Ben Slater; Graham Budd; Charles H. Wellman; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Cambrian; acritarchs; organic-walled microfossils; small carbonaceous fossils; Greenland; diversity; disparity; taxonomy; taphonomy; Crustacea; plankton; Historical Geology and Paleontology; Historisk geologi och paleontologi;

   Abstract : The early Cambrian Buen Formation of North Greenland is celebrated for hosting one of the oldest Cambrian Burgess Shale-type deposits known to date – the Sirius Passet Lagerstätte. Further south in a shallower shelf facies belt, the Buen Formation yielded organic-walled microfossils (OWMs) that were originally described with a focus on acritarchs. READ MORE