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Telomeres as indicators of chronological and functional age and ageing in birds
Kyliánková, Hana ; Albrecht, Tomáš (advisor) ; Aghová, Tatiana (referee)
The explanation of ageing processes belongs to the most challenging topics in evolutionary biology. This bachelor thesis provides a basic summary of evolutionary hypotheses of ageing, along with an overview of proximate ageing mechanisms. Main focus is on telomeres and the dynamics of their shortening. Telomeres are non-coding, repetitive sequences of DNA protecting the ends of eukaryotic chromosomes against degradation. They usually shorten with each cell division in most somatic cells until they reach the critical limit (the so called Hayflick limit), when the cell undergoes the replicative senescence and does not divide anymore. Various factors, such as physiological/oxidative stress, stage of reproduction/reproductive investments, and diseases/parasites, can influence telomere length dynamics. Recent studies indicate that telomere length is a useful biomarker for estimating functional, or biological age, but at the same time length of telomeres cannot be used to estimate chronological age. Molecular methods which can be used to measure telomere length, and their potential limitations, are also discussed in this thesis. Finally, I provide an overview of studies focusing on telomere dynamics in bird-oriented research. Key words: Telomeres, ageing, qPCR, birds, oxidative stress
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Valuation of FOXCONN CZ s.r.o.
Albrecht, Tomáš ; Smrčka, Luboš (advisor) ; Schönfeld, Jaroslav (referee)
The aim of the Master´s Thesis Valuation of FOXCONN CZ s.r.o. is to determine the objectified value of the company FOXCONN CZ s.r.o. as at 31. 12. 2015 from the perspective of an external analyst. The Master´s Thesis is divided into two main parts. The theoretical-methodological part describes the procedure of calculation single methods leading to the final valuation of the company. The emphasis is mainly on description of valuation, strategic analysis, financial analysis, planning of value generators, financial plan and the individual valuation approaches. The practical part is based on the application of particular procedures and calculations, described in the theoretical part. Results of every single chapter are properly commented using relevant information and other facts. The conclusion contents the summary of gained results leading to the determination of final value of the company. Method of free cash flows to equity (FCFE) was used for valuation.
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Secondary male ornamentation and extra-pair paternity: experimental manipulation in collared flycatchers (Ficedula albicollis)
Šplíchalová, Petra ; Albrecht, Tomáš (advisor) ; Svobodová, Jana (referee)
Extra-pair paternity, resulting from sexual promiscuity, is frequently detected in socially monogamous passerines. Previous studies on extra-pair paternity in birds have identified several traits correlated with increased fertilization success of males. However, the effect of experimental manipulation of ornament expression on male fertilization success has only seldom been evaluated. The aim of this thesis is to reveal the potential link between the size of a trait suposedly playing a role in female mate choice decision and male fertilization success in collared flycatchers (Ficedula albicollis), using experimental manipulation of male forehead white patch size. In addition, mating success, mating speed of the manipulated and control individuals and size of a brood (a proxy for female reproductive investments) were evaluated. Results indicate that forehead patch size manipulation did not affect male social pairing success (mating speed), his social mate reproductive investments (brood size) or male extra-pair and within-pair fertilization success. Keywords: extra-pair paternity, sexual selection, reproductive success, collared flycatcher
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Environment and avian song: case of South African birds
Mikula, Peter ; Albrecht, Tomáš (advisor) ; Linhart, Pavel (referee)
Relationship between animal signalization and environmental conditions, where these species are living, is one of crucial topics of ecology. Using two complementary statistical approaches (fourth-corner and RLQ analyzes) I investigated geographical variation in parameters of bird vocalization in South Africa (RSA) and Lesotho. Altogether, I used nine quantitative and five qualitative acoustic traits for 472 bird species and nine environmental variables which could significantly influence parameters of their vocalization. My results supported findings of previous studies about the important effect of body size on species-specific vocal characteristics. In passerines, analyzes corrected for body size showed that the number of elements and element types were increasing with variability of natural conditions and were highest in very arid and climatically unpredictable areas. Element and element type rate were positively associated with altitude. Minimal song frequency in passerines and frequency range of vocalization in other birds were negatively correlated with average temperature of warmest and coldest month of the year, respectively. Similarly, environmental variables significantly influenced distribution of several qualitative song traits in passerines. Passerines, where female song and...
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Extrapair paternity and adaptive explanations of female promiscuity in birds
Siegelmannová, Nikola ; Albrecht, Tomáš (advisor) ; Poláková, Radka (referee)
Extra-pair paternity are commonly detected in populations of social monogamous birds, however it remains unclear how this strategy evolves and is maintained. Several adaptive and non-adaptive explanations were, proposed to explain female promiscuity with major attention being devoted to the hypothesis of genetic benefits to females in form of good or compatible genes for their offspring. These theories assume that extra-pair offspring are of better quality than their maternal half-sibs in the nest. This thesis summarizes available studies that have compared benefits and costs for males and females from extra-paired paternity and evaluated the adaptive explanation of female promiscuity. It seems that the evidence for inderect benefits to female promiscuity are generally week in birds, and other mechanisms, such as sexual conflict or genetic correlations between the sexes may play a role in explaining the female bird propensity to copulate with extra-pair mates. Powered by TCPDF (www.tcpdf.org)
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Latitudinal trends in avian life-histories
Krejčířová, Zuzana ; Albrecht, Tomáš (advisor) ; Reif, Jiří (referee)
Most studies on bird focus on northern temperate zone species. However, the vast majority of birds occupies tropical environments. In birds, differences between tropical and temperate zone species in various life-history traits have long been assumed. These differences may reflect variation in solving the survival-reproduction trade-off, with temperate species preferring actual reproduction over the survival and tropical species preferring the oposite. In this bachelor thesis I summarize the result of literature search focusing on latitudinal trends in selected life-history traits in birds. In the first part of thesis I provide an overview of differences between the temperate and tropical zone in environmental conditions often assumed to closely affect the evolution of avian life histories. In the second part of the thesis, I focus on particular life-history traits where the differences between tropical and temperate species were detected. Latitudinal trends in chosen life history associated traits (clutch size, longevity and life span, basal metabolic rate) indeed seem to correspond with the general prediction of comparatively slow pace of life in tropical species.
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Post-copulatory sexual selection and sperm phenotypes
Bílková, Karolína ; Albrecht, Tomáš (advisor) ; Děd, Lukáš (referee)
Postcopulatory sexual selection has two basic components, sperm competition and cryptic female choice. In this thesis I summarize available data of the influence of postcopulatory sexual selection on sperm morhology and phenotype, focusing on both vertebrates and selected invertebrate taxa. In the first part of my thesis, I provide an overview of sperm phenotype adaptations that are influenced by the sperm competition and may closely determine male fertilization success. These are the length of sperm, sperm swimming speed and motility, longevity of sperm and the amount of ejaculate produced. Sperm phenotypes that evolve under strong postocopulatory selection may also involve morphological adaptations alowing sperm to mutually cooperate in the female reproductive tract. The cryptic female choise, in which female selectively use sperm after the sperm enters her reproductive tract, and the coevolution of sperm morphology and female reproductive tract is presented in the second part of this thesis. Powered by TCPDF (www.tcpdf.org)
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The utilization of "doubly labelled water" method in studies of avian ecology
Míčková, Kristýna ; Albrecht, Tomáš (advisor) ; Kubička, Lukáš (referee)
Doubly labelled water method is used to estimate CO2 production and energy expenditure. The method is based on the application of water containing rare hydrogen and oxygen isotopes, and estimation of the difference in elimination of these isotopes from the body (used as an indirect estimate of CO2 production), which is measured mostly from two blood samples taken over a defined time interval (usually 24 hours). Here I summarize the assumptions and methodological approaches associated with the use of the doubly labelled water method in bird studies. Studies on birds typically evaluate energy expenditure associated with prasitic infections and immune response, ageing, investments into the reproduction, flight and migration, ornamentation. In comparison with other methods doubly labelled water is appropriate for measurement of energy expenditure associated with various aspects of biology in targeted individuals. Key words: Doubly labelled water, energy expenditure, metabolism, birds, reproductive investments, flight costs
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Latitudinal trends in prevalence and diversity of parasites and pathogens of vertebrates
Wichová, Eliška ; Albrecht, Tomáš (advisor) ; Reif, Jiří (referee)
The latitudinal diversity gradient (LDG) indicates a decrease of species richness from equatorial regions toward poles and it is known as a biogeographical pattern applicable for the majority of free-living animals and plant species. Many hypotheses link this phenomenon with a high measure of biotic interactions at low latitudes, which play an important role in the origin and maintenance of species diversity. One of these interactions is the host-parasite relationship. The aim of this thesis is to summary recent investigations of parasitic and pathogenic occurence according to latitude for representative groups of host vertebrates with focus on diversity (number of infectious species per host species) and prevalence (the total number of infected cases per whole population at specific time). Using comparative approaches was revealed, that latitudinal gradient in richness and prevalence is characteristic particularly for vector-born parasites of terrestrial vertebrates and ectoparasites of marine fish.
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Flight initiation distances and life histories in birds: comparison of intra- and interspecific approaches
Brzobohatá, Tereza ; Albrecht, Tomáš (advisor) ; Klvaňa, Petr (referee)
Information about the distance, in which the birds flee from predators, may help us to better understand avian escape behavior and stress responses. These distances are influenced by many life-history traits and related factors, both on intraspecific and interspecific levels. This bachelor's thesis is trying to summarize the current knowledge of agents influencing flight initiation distances (FID) of birds, in the form of a literary research. The first section deals with antipredator behavior in birds, and explains methods that are used for measuring critical distances. In the second part of thesis, factors affecting flight initiation distances on intraspecific level are described. The main emphasis is on impact of age characteristics, body sizes, reproductive investments and geographical distribution. The last chapter summarizes the information about relationships between FID and life-history traits on interspecific level. The age of the individual, levels of stress hormones, the effect of the season and biotop are described in detail. Powered by TCPDF (www.tcpdf.org)
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