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Comparative development of scales and surfaces of fishes
Uherková, Michaela ; Černý, Robert (advisor) ; Vaškaninová, Valéria (referee)
1 Abstract The body surfaces of cartilaginous fishes (Chondrichthyes) and bony fishes (Osteichthyes) are composed of scales, with individual scale types differing in their morphological description, stratification, morphogenetic development and representation in each group. In fossil species, we encounter hard bony shells or plates, which gradually change during evolution to flexible scales of the elasmoid type, these are found in contemporaneous representatives of the bony fish group (Teleostei). Recent scale types found on the surface of present-day fish-like vertebrates include modified cosmoid scales, ganoid scales, placoid scales and elasmoid scales. Odontodes, which include placoid scales, ganoid scales, vertebrate oral teeth and pharyngeal teeth, are a key component in the evolutionary development of all these body surfaces. Odontodes form the basic structural unit of all dermo-skeletal structures and, from an evolutionary point of view, have evolved into the scales and oral teeth of vertebrates. Because of the interesting correlation between teeth and scales, a separate chapter of the literature review will be devoted to theories of the origin of oral teeth. The present bachelor's thesis discusses the evolutionary development of scales of cartilaginous fishes and bony fishes with respect to the...
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Diversity and function of pattern structures in the microworld
Hirnerová, Anna ; Škaloud, Pavel (advisor) ; Němcová, Yvonne (referee)
This thesis summarizes current knowledge of patterns and structures at various scales, with an emphasis on the use of these patterns in the microworld and also on the materials that are most often used. Patterns are applied in all areas of natural processes and human activity. There are many analogous models at different scales, but we do not know if they have the same self-organizing mechanisms. Many patterns formed by microorganisms can be prepared without their presence, on the basis of physical and chemical methods, so they are probably created under certain parameters that can be influenced by a given protist. These patterns are evolutionarily advantageous for microorganisms, because they provide them with a number of functional adaptations, mainly in connection with defense against predators and movement in the water column, which is based on the organism's life strategy. The mathematical description of the pattern is extremely important for its further research and for determining the laws that have allowed the organism to benefit from its parameters. Keywords: pattern, structure, convection, reaction - diffusion model, geometry, protist, microorganism, skeletons, shells, scales
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The significance of silica structures in chromist microorganisms.
Nováková, Dora ; Škaloud, Pavel (advisor) ; Němcová, Yvonne (referee)
The silica is one of the most common elements in the Earth's crust. During erosion it is released in soluble form to the environment, where some organisms can accumulate the silica and incorporate it to their bodies by biosilicification process. The organsims possessing this ability are widespread either when considering their position in eukaryotic tree of life, or their abundance in natural ecosystems. As a result, the whole global biogeochemical cycle of silica is controlled by biosilicificated organisms. In Chromista microorganisms, the silica is loaded to so-called "silica deposition vesicles" - membrane surrounded compartments, in which the silica is polymerated and formed into the final shape of silica structures during an ingeniously controlled in vivo process. Apparent differences in the process of silica deposition among Chromista microorganisms imply that this ability has developed independenty and repeatedly within the group. The most common silica structures are scales, bristles, cases, skeletons and cysts. The analogical structures often originated independently in unrelated lines of Chromista by means of convergent evolution. On the contrary, in some lineages of Chromista, the ability of biosilicification was suppressed. It is therefore very likely that the silica structures should...
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Evolution of silica structures in SAR protists
Čížková, Natálie ; Čertnerová, Dora (advisor) ; Kulichová, Jana (referee)
Silicon is an important element in the earth's crust. In nature it mainly occurs in the form of silicic acid. This element is used by marine and freshwater organisms to form their siliceous structures. The organisms that make up these structures are located throughout the phylogenetic tree and are not limited just to protist groups. The SAR line includes Stramenopila, Alveolata and Rhizaria. The main protist taxa forming the mentioned siliceous structures are in these groups. These are mainly diatoms, silicoflagellates, radiolarians and the group chrysophyceae. The formation of siliceous structures usually provides evolutionary benefits to organisms, such as protection of the cell from actions of biotic and abiotic factors. The availability of dissolved silicon changed during evolution, thus affecting the appearance and functionality of the structures of individual species. Structural changes were manifested by thinning of the shells, change of cell size, enlargement or decrease of pores, increase of the number of thorns or, conversely, their loss. The individual lines thus had to choose the best possible strategies in response to the decreasing availability of silicic acid. Therefore, there was frequent competition between the groups for the remaining dissolved silicon. The current diversity of...
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Evaporative water loss in geckos of the genus Paroedura
Myslíková, Tereza ; Starostová, Zuzana (advisor) ; Okrouhlik, Jan (referee)
Keeping a balanced state in terms of liquids in an organism, especially evaporative water loss regulation, is essential for all terrestial animals, including reptiles. Respiratory water loss and cutaneous water loss account for the highest percentage of total water loss. For this reason, the degree of evaporative water loss in reptiles can be primarily influenced by body dimensions, metabolism intensity and morphology of body surface scales. This thesis focuses on water loss through evaporation in Madagascan Paroedura geckos. The Paroedura are suitable for this research because they represent a monophyletic genus with a strongly supported hypothesis about phylogenetic relationships. The thesis adds some facts to this theory. At the same time, individual Paroedura species differ in body dimensions and habitat preference. The aim of the thesis was to find out whether individual representatives of Paroedura differ in TEWL, to specify the characteristics of the ancestral state of TEWL in this genus and to test which morphological and physiological factors influence TEWL. Further aim was to measure cutaneous water loss. Measuring was carried out by flow- through respirometry. The results show that individual representatives of Paroedura differ remarkably in TEWL figures. The reconstruction of the...
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The significance of silica structures in chromist microorganisms.
Nováková, Dora ; Škaloud, Pavel (advisor) ; Němcová, Yvonne (referee)
The silica is one of the most common elements in the Earth's crust. During erosion it is released in soluble form to the environment, where some organisms can accumulate the silica and incorporate it to their bodies by biosilicification process. The organsims possessing this ability are widespread either when considering their position in eukaryotic tree of life, or their abundance in natural ecosystems. As a result, the whole global biogeochemical cycle of silica is controlled by biosilicificated organisms. In Chromista microorganisms, the silica is loaded to so-called "silica deposition vesicles" - membrane surrounded compartments, in which the silica is polymerated and formed into the final shape of silica structures during an ingeniously controlled in vivo process. Apparent differences in the process of silica deposition among Chromista microorganisms imply that this ability has developed independenty and repeatedly within the group. The most common silica structures are scales, bristles, cases, skeletons and cysts. The analogical structures often originated independently in unrelated lines of Chromista by means of convergent evolution. On the contrary, in some lineages of Chromista, the ability of biosilicification was suppressed. It is therefore very likely that the silica structures should...
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International trade in pangolins (\kur{Manis} spp.)
VÁŇOVÁ, Jana
The aim of this work was to evaluate international trade with Manis. spp. according to the CITES database during the period 2002-2013. Manis spp. was classified in appendix II CITES in 1995. In 2000 there was an unsuccesfull attempt to reclassified Manis spp. to appendix I CITES. In this year the zero quota was set for Asian pangolins for commercial purpose. A rapid increase of an illegal trade was noticed after the setting of zero quota. The most frequent trade with pangolins was in these forms: 1) derivatives, 2) specimens, 3) scales, 4) live pangolins and 5) skins. Asian pangolins´ species were traded mostly in forms of derivatives, specimens, scales and skins in the period 2002-2013. M. javanica and M. pentadactyla with medium and large distribution area were quantitatively the most traded species, respectively. Main importers of Asian forms of pangolins were: USA (derivatives and specimens), China (scales in kg) and Indonesia (scales in pieces) and Mexico (skins). The African pangolin M. tricuspis was the third most frequent species in the international trade and was traded especially in form of live pangolins. M. tricuspis lives in one of the largest distribution area. Main importer of live pangolins was Italy. Breeding pangolins in captivity is due to the specific feeding requirements demanding. There are about 46 individuals of pangolins in Zoos all over the world, whereas in Europe there are only 2 pangolins in the Leipzig Zoo.
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Age and growth of the European grayling Thymallus thymallus (L.) originally from different localities - assessment based on the scale analysis
CHYTRÝ, Martin
The main aim of this thesis is to evaluate and to compare the age and length growth of European grayling in selected watercourse in the South Bohemia (Blanice vodňanská, Volyňka, Teplá Vltava a Otava) and in Austria (the Traun River and the Salzach River), focusing on the watersources of the Teplá Vltava River and the Traun River. Possible rules adjustment of sport fishing can give reasons eventually to be done on the basis of results in order to protect and to strenghten natural populatin of grayling. 53 individuals (fish) were studied in total which were in observed localities fished from 2011 to 2015 using power generator or fishing rods. The determination of age and growth were based on analysis of scales of the biggest individuals. The method of Rosa Lee (1920) was used for back-calculation of length growth. The oldest fish, 8 years old, was found among graylings in the Teplá Vltava River. The oldest fish from studied group of fish in Austrian Traun River where graylings trophy are occured belonged to the age group 5+. Graylings from the Traun River came up to faster growth distinctly which is related to more optimal living conditions (water temperature, the amount of food) in the pariticular watersource. Furthermore graylings from observed watersources in the South Bohemian region already grow up to minimum fishing length (30 cm) at the age of 3 4 years old. They can participate in natural reproduction only once or twice a life. Increase of miminal fishing length is absolutely eligible and it is the reason for increasing number of natural spawning and strenghtening of indigenous population of grayling.
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