National Repository of Grey Literature 135 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Evolution of vipers and the role of key innovations in their diversification
Waldhauser, Vojtěch ; Šmíd, Jiří (advisor) ; Gvoždík, Václav (referee)
The family Viperidae consists of 36 genera, containing more than 350 species in total. The family is distributed throughout Africa and most of Eurasia, however the greatest diversity is located in North and South America, where more than 40 % of the viper species can be found. The family is thus missing only in Australia, New Guinea, Madagascar, New Zealand and a number of other islands and archipelagos. As with most reptiles, they are also almost completely absent from polar regions, with the exception of Vipera berus, the only snake that has ventured north of the Arctic Circle. Their relative evolutionary success is attributed to many so called "key innovations", which include solenoglyphous dentition, viviparity of many genera or heat- sensing pits in the subfamily Crotalinae. Vipers are not only interesting because of their evolutionary history, but they are also subject of important medical studies regarding their venom and toxicity. WHO estimates that around 100,000 people worldwide may die from snake bites each year. This thesis presents a summary of our current knowledge of the evolutionary history of this family, including phylogeny and biogeography, and contemplates the mechanisms behind its amazing diversity.
Role of evolutional mechanisms in designing of acoustic signals
Rulfová, Alena ; Policht, Richard (advisor) ; Linhart, Pavel (referee)
Acoustic communication is a wide-spread phenomen in all animal taxones. The theme of evolutional mechanisms and their functioning in acoustic communication has become more and more frequently studied during last years, and geographic variation in acoustic signals has been reported in various taxa such as insect, birds, anurans and mammals. However, some evolutional mechanism still remain poorly understood. The mechanisms comprise mainly stochastics forces such as genetic drift and bottleneck or cultural drift. Genetic drift causes stochastic changes in acoustic signals, whereas bottleneck probably primarily spawns reduction of acoustic variability. Some acoustic parameters are shaped by habitat and others by species' phylogeny. Physical environment and other ecological factors play important role in shaping vocalizations in most species, and thus distantly related populations occupying similar habitats may possess very simmilar vocalization. Because of that, revealing phylogenetic pattern is possible only by careful cladistic analysis of vocal characters in taxa that have simple songs or calls that are not learned, and whose habitat distributions are well understood. By finding the proper acoustic parameters we can also e.g. map connection between acoustic divergence and glaciations, history of colonisation...
Evolution of sex chromosomes and karyotypes in geckos (Squamata: Gekkota)
Koubová, Martina ; Kratochvíl, Lukáš (advisor) ; Choleva, Lukáš (referee)
Gekkota is species-rich and diverse group of squamate reptiles (Reptilia: Squamata) with almost global distribution. There were many hypothesis defined about the phylogeny of this group, traditionally based on morphological data. The essential reversal in phylogenetic relationships occurred with the entry of molecular analysis, whose differ in their conclusions from traditional approach fundamentally, even in positions of mayor lineages. This fact has an essential importance for the karyotype evolution study of this group. The ancestral state is considered as 2n=38 karyotype with all chromosomes acrocentric. In some species is this karyotype kept, in another there is apparent an influence of chromosome changes, mostly Robertsonian fusions and pericentric inversions. Diploid chromosome number is from 16 to 46, but the most common is 2n=38 karyotype of mostly acrocentric chromosomes, gradually decreasing in size. The interesting character of this group is extraordinary variability in sex determining mechanisms. We can find there species with temperature sex determination and also species with genotypic sex determination (both types XX/XY and ZZ/ZW). Sex chromosomes data are documented in only 17 species. Sex chromosomes differ rapidly in their morphology and their homology between sister taxa was not proved...
Overview of the family Deinotheriidae C.L. Bonaparte, 1841 [Mammalia, Proboscidea] with direction to fossil discoveries in Czech Republic.
Šmejkal, Roman ; Mazuch, Martin (advisor) ; Wagner, Jan (referee)
This work presents the family Deinotheriidae including the subfamily Chilgatherinae. Morphological differences of teeth point to anatomical differences between the genders Chilgatherium, Prodeinotherium and Deinotherium. Further, the anatomical differences of skull and postcranial skeleton of the Deinotherinae subfamily are described. The Extension of the family Deinotherium is tied to the migration routes from Africa to Asia and Europe. The Occurrence in the Czech Republic is confirmed by 2 important discovery sites. The first one is located in Horní Ves near Franzensbad where the skeleton of the species Prodeinotherium bavaricum was discovered. The second one is located near Česká Třebová and represented by the fragments of the lower jaw of the species Prodeinotherium cuvieri. The discussion focuses on the use of the lower tusks and the method of food intake.
Habitat shifts to aquatic environment and back to dry land in the evolution of Coleoptera
Sýkora, Vít ; Fikáček, Martin (advisor) ; Král, David (referee)
The order Coleoptera (beetles) includes both terrestrial and aquatic species. The whole order as well as for all suborders (Archostemata, Myxophaga, Adephaga and Polyphaga) in ancetrally terrestrial. Habitat shifts occured in all suborders except Archostemata. A single shift to aquatic environment is probable in Myxophaga and Adephaga, multiple independent shifts from aquatic to terrestrial environments took place in Polyphaga. Multiple secondary habitat transitions back to terrestrial life style occured in Adephaga, Myxophaga and Polyphaga. However, phylogenetic relationships and/or detailed habitat requirements of adults and larvae are still unknown for many groups. That is why a reliable reconstruction of the evolution of habitat transitions between aquatic and terrestrial environment is still impossible in many cases. Key words: Coleoptera, habitat shifts, aquatic environment, terrestrial environment, evolution, phylogeny, biodiversity, morphology, adaptation
Phylogeny and ecology of family Planorbidae
Běláčová, Kateřina ; Juřičková, Lucie (advisor) ; Lorencová, Erika (referee)
Phylogenetics is a sub-discipline of biology which focuses on classification of organisms based on their evolutionary development. Morphological and anatomical features have been traditionally used in reconstruction of phylogeny but with the onset of modern technology their role has been partly taken up by molecular analysis. Family Planorbidae is a very diverse group that includes species with very different morphology. This work aims to provide an overview of the phylogeny within Planorbidae family and discuss the importance of the individual features used in determination based on the results of the published studies.
Current view on the biology of theropod dinosaurs
Honskus, Adam ; Teodoridis, Vasilis (advisor) ; Řezníček, Jan (referee)
This bachelor thesis hes summarised available data from morphology, anatomy, ecology, ethology, ontogeny and phylogeny of theropod representatives of the clade Dinosauria that are based on the recent results deriving from the application of modern scientific methods and technologies. Main methods are laser scanning, computed tomography, electron microscope analysis and virtual and physical model reconstruction. Application of these results have changed radically historical and dogmatic point of view on this fascinating group of dinosaurs that had ruled on the Earth for more than 150-million years. Powered by TCPDF (
Molecular cztogenetic analysis of adaptive radiation in the gecko genus Paroedura (Squamata:Gekkota)
Koubová, Martina ; Kratochvíl, Lukáš (advisor) ; Šťáhlavský, František (referee)
Paroedura genus includes 17 described species endemic to Madagascar and the Comoros Islands, where they went through a significant adaptive radiation. The genus Paroedura is monophyletic and well supported hypothesis on phylogenetic relationships among its species was published. Species vary considerably in body size and morphology and in preferences for habitat, some species live in sympatry. The genus Paroedura belongs to cytogenetically poorly studied family Gekkonidae which exhibits high variability in modes of sex determination and in comparison with basal gecko lineages, also considerable variability in the chromosome number and morphology. Karyotypes of only two species of the genus (P. picta, P. sp.) have been published. The aim of my thesis was to describe karyotypes of both sexes in all available species of the genus using conventional and molecular cytogenetic methods, to perform the phylogenetic analysis of karyotype evolution and chromosomal rearrangements in the genus, to assess the role of these rearrangements in the speciation of the genus and to detect sex chromosomes. I acquired karyotypes of both sexes in nine species representing the most of major phylogenetic lineages of the genus. According to the results, species can be divided into three groups according to diploid...
Genetic variability of the genus Alburnoides in Azerbaijan
Omelchenko, Dmytro ; Švátora, Miroslav (advisor) ; Vukićová, Jasna (referee)
The Caucasus region is characterized by high rate of endemism and taxa richness of fishes. Azerbaijan is a country situated on the border between Europe and Asia with rivers flowing in the Caspian Sea. Natural environment of this country is represented by various habitats with diverse ichthyofauna. This region is very attractive for biogeographical studies because it lays on the border of two different ecoregions. Even on the modern stage of scientific cognition, there is still lack of data about freshwater fishes from that region. Spirlins or rifle-minnows (Alburnoides Jeitteles, 1861, Actinopterygii, Cyprinidae) is a genus of small freshwater fishes and it has been chosen as a focus of this thesis because of numerous reports of new species from surrounding countries. The presented thesis is one of the seldom molecular studies trying to reveal the taxonomical situation within the genus Alburnoides, describe the phylogenetic relationships between geographically isolated populations, and provide biogeographical implications for fishes in the Caspian Sea river basins. Both mitochondrial (cytochrome b, cytochrome oxidase subunit I) and nuclear (RAG1, rhodopsin) markers were used in the study and the Maximum Likelihood, Maximum Parsimony and Bayesian phylogenetic analyses were performed. Further, the...

National Repository of Grey Literature : 135 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.