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Environmental gradients in canyon-shaped reservoirs
Stodola, Jakub ; Petrusek, Adam (advisor) ; Seďa, Jaromír (referee)
The occurrence of environmental gradients in canyon-shaped reservoirs is influenced mainly by the size of reservoir and water retention time. The reservoir must be large and deep enough for environmental gradients to occur there. In such reservoirs vertical and horizontal gradients can be found. Presence of vertical gradients in lakes is relatively common, whereas horizontal gradients abound in deep canyon reservoirs. An example is the gradient of nutrients, the quantity of which decreases in the direction from the inflow towards the dam. Vertical abiotic gradients are the same for reservoirs and lakes. These are mainly gradients of light, heat, dissolved and oxygen. Some abiotic horizontal gradients may be present in both to reservoirs and lakes. The abiotic gradients also often affect the biotic ones. For example the gradient of nutrients affects the gradient of all organisms in the reservoir. Each species living in the reservoir prefers different type of environmental conditions, which may be given by a combination of these gradients. The areas preferred by particular cladoceran species can overlap quite extensively. In the Daphnia longispina species complex, co-occurrence of parental species may result in interspecific hybridization, and possibly formation of hybrid zones. The hybrids can often...
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Genomic approaches for studying speciation
Vozárová, Zuzana ; Reifová, Radka (advisor) ; Hulva, Pavel (referee)
Technological advances in DNA sequencing along with the emergence of new informatics approaches have created new possibilities in many biological fields. In this bachelor thesis, I will focus on the informatics approaches used in speciation genomics, that is research field focused on the problematics of the origin of new species. I will introduce some statistical methods used by these approaches for parameter estimation. The four particular methods I will write about are Maximum likelihood estimation, Bayesian model, Markov chain Monte Carlo and Iterative approach. I will describe several methods used for the detection of interspecific hybrids and recent as well as historical interspecific gene flow. These methods include NewHybrids, the hybrid index, genomic and spatial clines and coalescent-based methods. The thesis demonstrates the usefulness of the connection of applied mathematics and genomics for addressing general biological issues, and speciation particularly.
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Environmental gradients in canyon-shaped reservoirs
Stodola, Jakub ; Petrusek, Adam (advisor) ; Seďa, Jaromír (referee)
The occurrence of environmental gradients in canyon-shaped reservoirs is influenced mainly by the size of reservoir and water retention time. The reservoir must be large and deep enough for environmental gradients to occur there. In such reservoirs vertical and horizontal gradients can be found. Presence of vertical gradients in lakes is relatively common, whereas horizontal gradients abound in deep canyon reservoirs. An example is the gradient of nutrients, the quantity of which decreases in the direction from the inflow towards the dam. Vertical abiotic gradients are the same for reservoirs and lakes. These are mainly gradients of light, heat, dissolved and oxygen. Some abiotic horizontal gradients may be present in both to reservoirs and lakes. The abiotic gradients also often affect the biotic ones. For example the gradient of nutrients affects the gradient of all organisms in the reservoir. Each species living in the reservoir prefers different type of environmental conditions, which may be given by a combination of these gradients. The areas preferred by particular cladoceran species can overlap quite extensively. In the Daphnia longispina species complex, co-occurrence of parental species may result in interspecific hybridization, and possibly formation of hybrid zones. The hybrids can often...
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