Search for dissertations about: "disruptive selection"
Showing result 1 - 5 of 14 swedish dissertations containing the words disruptive selection.
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1. Evolution of Spur Length in a Moth-pollinated Orchid
Abstract : There is considerable evidence that pollinator shifts can explain many differences in flower morphology between closely related plant species, but the extent to which pollinator shifts can explain the maintenance of among-population variation in floral traits within species is poorly known. In this thesis, I combined comparative and experimental approaches to examine the evolution of floral traits in the moth-pollinated orchid Platanthera bifolia. READ MORE
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2. Adaptive evolution in multidimensional trait spaces
Abstract : Negative frequency-dependent disruptive selection, which arises due to the interplay between organisms of a population and their environment, is an important element driving phenotypic diversification and even speciation. Such selection regime can result from frequency- and density-dependent interactions between the organisms and their environment, so that the fitness landscape itself changes as the population evolves. READ MORE
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3. Consequences of the Domestication of Man’s Best Friend, The Dog
Abstract : The dog was the first animal to be domesticated and the process started at least 15 000 years ago. Today it is the most morphologically diverse mammal, with a huge variation in size and shape. READ MORE
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4. On Speciation in Birds – Genomic Signatures across Space and Time
Abstract : The process of speciation is a cornerstone in evolutionary biology. In Darwin’s On the Origin of Species, he described how he imagined that a new species would evolve to fill an empty niche. This focus on ecology shifted with Mayr towards the importance of isolation, and for many decades the geographic modes of speciation were debated. READ MORE
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5. Diverse effects of endocrine-disruptive chemicals on Leydig and adrenocortical cell steroidogenesis in rodents and humans
Abstract : We are living in a man-made world and often exposed to different chemicals known as endocrine disrupting chemicals (EDCs) that negatively influence our hormonal system. These compounds have the potential to interrupt a normal steroidogenesis and result in harmful effects on the reproductive health of humans and among other organisms. READ MORE