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Diversity of Epilobium and methods to explore their hybridization
Kuchyňková, Lenka ; Kaplan, Zdeněk (advisor) ; Šemberová, Kristýna (referee)
Willowherbs (Epilobium) belong to the genera whose evolution is significantly affected by interspecific hybridization. Although this process often generates evolutionary novelties and leads to speciation, it can also result in genetic erosion and extinction. This thesis is mainly focused on the Czech Epilobium species that are potentially endangered by interspecific hybridization. The emphasis falls on the group of rare mountain willowherbs including E. nutans, E. alsinifolium and E. anagallidifolium. In addition to frequent interspecific hybridization, the research of this group is also complicated by the subtlety of distinguishing morphological features. The review also summarizes the available methods that can be used to study interspecific hybridization in the follow-up thesis.
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The Current Extinction of species
Schätz, Filip ; Storch, David (advisor) ; Hulva, Pavel (referee)
This bachelor thesis deals with the current process of species extinction. The main aim of the thesis is to answer the question how we can accurately describe this process. The understanding of this process is based on the limited sample of extinct species known to us, provided by the IUCN Red List. The sheer number of extinct species is affected by the use of different species concepts, the synonymy of binomial names and the difficulty of tracking individual extinction events. The Red List sample is subject to strong selection bias, so currently there are only reliable records of extinctions of groups of birds and mammals. These extinctions are mainly associated with their occurrence on islands. For other taxa, records of extinctions are sporadic, so the status of the current extinction process in these groups is unknown. It is not possible in most cases to relate to these groups the knowledge resulting from the study of different taxa. Estimates that attempt to describe the process beyond our knowledge also suffer from shortcomings. While the problems of expressing actual extinction rates stem from our ignorance of biodiversity, the inaccuracies of the SAR curve back-extrapolation method are mainly due to the attempt to generalise the overly complex effect of range loss on species numbers. The...
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Conservation genetics of Galápagos mockingbirds: from immune genes to genomes
VLČEK, Jakub
In this thesis I have dealt with the population genetic processes of mockingbirds in the Galápagos Islands ( Mimus ) in relation to the limited island area, from the perspective of two types of immune genes and the genome-wide approach. The thesis starts with an introduction to population genetic concepts relevant to conservation genetics followed by description of immune genes: the major histocompatibility complex (MHC) and the Toll-like receptors (TLR). In the final part of the introduction, I address how genetic drift, selection and inbreeding shape genome-wide genetic patterns in small populations. The introduction is followed by four chapters, beginning with an examination of MHCII polymorphism in populations of mockingbirds in the Galápagos Islands. The study of the relationship between MHCII and the abundance of ectoparasites is the content of the second chapter. The third chapter shows how polymorphism of TLRs is shaped by interaction of genetic drift and natural selection. The last chapter deals with the effects of limited island size on inbreeding and genetic load, supported by inferences of the past demography of mockingbirds. The thesis concludes with a summary of the results and their potential implications in the field of conservation genetics.
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Morphological, behavioural and physiological adaptations of island-dwelling birds
Krpcová, Alena ; Albrecht, Tomáš (advisor) ; Mikula, Ondřej (referee)
Morphological, behavioural and physiological adaptations of island-dwelling birds Alena Krpcová prof. Tomáš Albrecht, Ph.D. Abstract Islands represent a model system of evolutionary biology. They are isolated environments in which specific ecological conditions often operate differently than on the mainland. In this context, island taxa develop unique morphological, physiological and behavioural adaptations, collectively referred to as island syndromes, through convergent evolution. This thesis aims to provide an overview of selected island syndromes that have been detected in a large group of vertebrates typically inhabiting islands, the birds (Aves). Attention is paid to body size, wing length and associated flightlessness, as well as changes in life strategies (life span, offspring care, clutch size and egg size), antipredatory behaviour and island tameness, and finally the relationship between the above-mentioned island syndromes and the extinction of island species caused by humans and the invasive organisms that accompany them. Factors operating in island environments that may influence the evolution of selected island syndromes are discussed, and it is suggested that reduced predation pressure on islands and an energetic trade-offs between investments in survival, defence and reproduction could be...
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Latest Ludlow chitinozoans from the Prague Basin: significanec for correlations and succession during Kozlowskii/Lau extinction events
Vodička, Jakub ; Fatka, Oldřich (advisor) ; Štorch, Petr (referee)
Two sections, Všeradice and Kosov, represent continuous sedimentary succession situated in the Prague Basin. No detailed research on stratigraphical level equal the N. kozlowskii graptolite zone focusing on chitinozoans, has not yet been conducted in the Prague Basin and is also very scarce globally. Limestone beds, examined for chitinozoans, were not very productive. Chitinozoan reaction on extinction is visible, if we compile data from both sections. The pre-extinct chitinozoan fauna is characterized by the Conochitinidae family. Samples from the post-extinct interval contained no chitinozoas. The interval of fauna recovery is characterized mainly by the Eisenackitina genera. In this interval, global zone for the uppermost Ludfordian, represented by E. barrandei, can be confirmed. In agreement with all the published literature, we have not found E. philipi, index taxa of the former global zone in the Prague Basin. E. lagenomorpha appears stratigraphically only slightly below E. barrandei and therefore it cannot substitute E. philipi, as it is used in Baltika region. chitinozoa, Prague Basin, Kozlowskii, Lau, extinction, Ludfordian, stratigraphy
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Development of the mammal assemblages during Quaternary climatic changes
Havlová, Tereza ; Mazuch, Martin (advisor) ; Nývltová Fišáková, Miriam (referee)
During the Quaternary there was a cyclical alternation of warm and cold periods - interglacials and glacials. Over the past 2.5 million years there was eighteen or twenty these cycles. These climate changes influenced by, except other, Milankovic cycles caused at sea level, extent of glaciation or distribution of vegetation zones. All these factors affected the communities of mammals, their distribution, migration and extinction of some groups of mammals. Area of continental and mountain glaciers expanded as well as levels of the ocean decreased during the glacials. Many species of mammals penetrated into new territory with the emergence of land-bridges a mammals from isolated areas could interact during cold periods. There was a retreat of glaciers and sea level rise and the migration routes through the land bridges was interrupted during the interglacials. Many, mostly island, populations were isolated and they were often developed to new endemic species. Key words: glacial, interglacial, climate changes, distribution, migration, extinction
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Extinction risk and population size
Váňová, Lenka ; Storch, David (advisor) ; Reif, Jiří (referee)
There is generally accepted assumption that the probability of extinction risk increases with decreasing population size. But it's not sure at all, to what extent does this relation really work in real populations. The amount of studies dealing with this topic is on the increase, but still it's necessary to carry on researching. Previous results indicate that inspected connection is indeed true in many populations, in other words, preferential extinction of less abundant populations functions properly. Yet the dependence isn't as unambiguous and strong as expected. Many exceptions are known as well, which demonstrate that low number of individuals doesn't always have to be a disadvantage in terms of survival chance. Such deviations can be found both in paleontological papers and among current populations. For example, mass extinctions represent that kind of a special exception because each of them was probably driven by a different mechanism, so in one case the abundance could be an advantageous trait, whereas in another it was rather disadvantage. In my work, I briefly mention themes referring to extinction in general and subsequently I try to summarize findings about the phenomenon of population size and its connection to extinction risk. On the basis of explorers' ideas and by means of...
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Mountains as islands
Kačabová, Petra ; Storch, David (advisor) ; Ferenc, Michal (referee)
In this paper I deal with island biogeography and its applicability to isolated mountaintops, as an ecological equivalent of true islands. I discuss both true and mountain islands regarding their origin and the influence of long-term climate evolution on Earth. I underline some features of mountain islands, resulting from their topography and the dissimilarities of both types of island barriers. I find that mountain and true island communities might or might not have a number of species in a state of equilibrium, caused by balance between species immigration on island and their extinction. If the number of species on island is not in equilibrium, species extinction is not balanced by species immigration. I consider patterns of island communities, mainly nestedness, which has been frequently studied on mountain, as well as true islands. I discuss distribution patterns concerning invertebrates. And finally, I concentrate on recent methods of moutain island research and discuss mountain island isolation issues in terms of global warming.
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Limitation of species richness
Szostoková, Kateřina ; Storch, David (advisor) ; Šímová, Irena (referee)
Currently we can find two main hypotheses of diversity dynamics in time in literature - bounded and unbounded hypothesis. According to bounded hypothesis diversity is limited, while unbounded hypothesis says that there are no obvious limitations of diversity. Evidence for these main hypotheses comes mainly from paleontological research, studies of phylogeny and comparison of local and regional diversity. None of these approaches give us clear and incontrovertible evidence of diversity limits. The aim of this work is to show some evidence that confirm (or not) limitation of diversity in mentioned kinds of biological research. Also, I would like to point out some critics and imperfections of used methods.
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Proposal for Debt Collection Improvement in the Enterprise
Gerlichová, Veronika ; Kyrych, Vladimír (referee) ; Musilová, Helena (advisor)
Bachelor thesis focuses on the suggestions for the improvement of security systems and debt collection for the selected entrepreneur. Specifies the basic theoretical information on legal, accounting, taxes and economics. In the analytical part is the entrepreneur briefly introduced and evaluated his current state of receivables. An integral part is also putting theory into practice by any proposals for tackling the problem.
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