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Karyotype evolution of selected families of entelegyne spiders
Kotz, Matěj ; Král, Jiří (advisor) ; Nguyen, Petr (referee)
The Araneoidea superfamily is a diverse clade of spiders with a great species diversity. The whole superfamily displays considerable conservativeness of observed karyotypes. Most likely ancestral karyotype in males is 24 acrocentric chromosomes with X1X2 sex determination system. The goal of this study is to explore the karyotype diversity of two araneoid families - Araneidae and Mimetidae. The majority of studied species exhibit the ancestral karyotype. In some species of the aformentioned families was observed sudden increase in chromosome numbers, up to 2n♂ = 52 in Araneidae and up to 2n♂ = 57 in Mimetidae. The latter number is the highest chromosome count observed in Entelegynae so far. Increase in 2n goes hand in hand with increase in sex chromosome numbers, leading up to X1X2X3X40 system in Araneidae and up to X1X2X3X4X5X6X70 in Mimetidae. I suggest polyploidy as a possible mechanism of the increase. To test this hypothesis, I measured the size of the genome using flow cytometry and used fluorescence in situ hybridization for the detection of 18S rRNA and 5S rRNA genes. For one species, probe for U2 snRNA gene was also optimized as part of this thesis. In many species studied, these techniques were used for the first time ever. In the case of the family Mimetidae, the largest genomes in...
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Echinoids, their evolution and response to the Cretaceous paleoenvironmental events
Hedánková, Karolína ; Košťák, Martin (advisor) ; Nohejlová, Martina (referee)
The bachelor thesis briefly summarizes knowledges about the evolution of sea urchins (Echinoidea; Echinodermata) with a focus on the successful order Spatangoida and their diversification in the dynamic Mesozoic environment. Attention is paid in particular to significant palaeoceanic changes, such as anoxic events (OAE = Oceanic Anoxic Event) and extinctions. Responses to OAE1-OAE3, as well as the last mass extinction (within the "Big Five") at the Cretaceous-Paleogene (K-Pg) boundary, are briefly discussed. Sea urchins, as an important part of benthic communities, prove to be a suitable model group not only for understanding the dynamics of evolution, but also successful strategies for surviving crisis events and new adaptations. Key words: Mesozoic, echinoids, evolution, events
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The evolution of SARS-CoV-2 virus during the pandemic of COVID-19
Karban, Šimon ; Tachezy, Ruth (advisor) ; Pačes, Jan (referee)
Coronaviruses are animal and human viruses which, in the case of humans, cause respiratory diseases. The genome of coronaviruses is non-segmented and encodes several structural and several non-structural proteins. As their genome consists of single-stranded RNA in a positive sense, they encode RNA-dependent RNA polymerase. The origin of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is uncertain and may never be known. However, this thesis covers up-to-date knowledge and the arguments for the main theories on the emergence of this virus. The pandemic of disease COVID-19 caused by the SARS-CoV-2 had an enormous impact on the health and lives of people worldwide. The length and severity of the pandemic were caused by the characteristic of the virus, transmissibility and asymptomatic type of infection with severe symptoms in elderly and chronically ill individuals and the fast evolution of the virus after its appearance in humans. This thesis will describe important characteristics of the most important variants of the virus and changes which gave them a selection advantage. In the end, trends in the evolution of SARS-CoV-2 will be discussed. Keywords: SARS-CoV-2, Coronaviridae, variants, phylogeny, origin, evolution
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Diversity of iris coloration during evolution of geckos (Gekkota)
Ozerskyi, Serhii ; Brejcha, Jindřich (advisor) ; Šmíd, Jiří (referee)
Iris is an anatomical structure that performs the function of a diaphragm in the visual system of the eye. It usually occupies most of the visible part of the eye. In addition to the main function - not to let light pass by the pupil, iris can play many different roles due to the great variability of its coloration. Iris can be part of a camouflage or aposematic color, play a different role in intra- or interspecific communication. In some species, its color changes depending on age, season, biological cycles, or even quickly become marked in response to stimuli. Geckos (Gekkota) are distinguished by a particularly large variety of iris color. And in many of them, the iris pattern resembles branching veins. What significance and evolution history this pattern has is of interest. I used various models of evolutionary reconstruction in the R program to study the evolution of veined pattern of coloration of the iris, as well as phylogenetic comparative methods and binary character evolution model to identify its connections with the fusion of life and the contrast in brightness between the eye and the eye ring. It was revealed that the veined pattern is an ancestral condition for geckos and is present in most modern species. Most precisely, the evolution of the vein pattern is described by all rates different...
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The Origin and Function of Heterostyly in Angiosperms
Nainar, Adam ; Münzbergová, Zuzana (advisor) ; Slovák, Marek (referee)
This bachelor's theses focuses on the phenomenon of heterostyly, which is an extraordinary feature of several representatives of plants from Angiosperm group like primroses /Primula/, based on two or three simultaneously occuring forms of one species, and expresses itself by opposite height configuration of anthers and stigmas, and that supports a reciprocal pollination and decreases a risk of self-pollination. The introduction in the beginning of the theses compares heterostyly with another various adaptations, which Angiosperms use them to avoid self-pollination. Further, the theses is divided to topical chapters, such as occurence and types of heterostyly (distyly, tristyly), and there are also many mentions about history of research of this phenomenon and about possibilities, according to which the heterostyly could have been evolved. In the theses there are mentioned other supplementary features, such as pollen grain differences as well. Also, this theses dedicates to interactions between heterostylous plants and pollinators and even to a brief genetic basis of heterostyly, which is a very important topic for explaining all these features. In the conclusion, there is mentioned a project named "The chase for cowslips", which is mapping populations of primroses - cowslips /Primula veris/ in...
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Evolution of hair in great apes and humans
Vejmělková, Anna ; Hora, Martin (advisor) ; Jarešová, Pavla Alexia (referee)
Humans are distinguished from other primates by their functionally naked body surface, caused by reduced body hair density and the type of hair called vellus, with which humans are predominantly covered. This type of hair represents fine and poorly pigmented hair, which, unlike terminal hair, is hardly visible. However, a reduced hair density can also be observed in other hominids, including the genus Homo and the genera Pan, Gorilla, and Pongo. In this work, we first compare the hair density of selected body parts for different species of primates. Next, we describe the structure and functions of hair and discuss hypotheses that explain the possible circumstances leading to a gradual decrease in hair density. We mainly focus on crucial hypotheses related to bipedal locomotion, inhabiting tropical savanna areas, parasites, or the influence of sexual selection. However, we also present some other hypotheses related to the wearing of clothes or the inhabiting of the aquatic environment by our ancestors. This work aims to compare these hypotheses, present arguments for and against them, and summarize their possible effects on the current state. Keywords: human, great apes, evolution, hair
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Evolutionary history, genetic diversity and human impact on selected leuciscids from the southern Balkans
Viñuela Rodríguez, Nuria ; Vukićová, Jasna (advisor) ; Perea, Silvia (referee) ; Kalous, Lukáš (referee)
- ABSTRACT - Fishes represent the most diverse group of vertebrates on Earth, with freshwater fishes accounting for half of this diversity, and occupying a mere 0.01 % of the world's water surface. The Balkans are considered a European hotspot of biodiversity, and its southern section is recognized as centre of ichthyological diversity, characterized by its exceptional richness and endemicity. Within the southern Balkans, the Ionian ecoregion stands out as one of the most isolated ichthyological regions in Europe due to its very complex geological history and the variety of events that influenced its ichthyofaunal composition. All fish species inhabiting the Ionian region are endemic, and most of them display reduced distribution areas with a marked geographic pattern. The western Aegean region, on the contrary, is considered a species-poor ecoregion within the southern Balkans, despite also harbouring a significant number of endemic species. However interesting the region of the southern Balkans is in terms of its ichthyofauna, there is a lack of knowledge for many of the fish species inhabiting them. In this thesis, we address some of these knowledge gaps for two representative genera, Pelasgus and Telestes, of the most diverse family in the area (Leuciscidae), with the aim to better understand the...
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Evolutionary Design of EEG Data Classifier
Kuželová, Simona ; Jawed, Soyiba (referee) ; Mrázek, Vojtěch (advisor)
Tato diplomová práce se zaměřuje na vývoj efektivního klasifikátoru pro klasifikaci kandidátů na základě extrahovaných vlastností z elektroencefalografického (EEG) signálu. K dosažení tohoto cíle byl použit genetický algoritmus pro výběr příznaků a optimalizaci klasifikátorů na základě pěti kritérií: minimalizace počtu příznaků, minimalizace doby inference a maximalizace klasifikační senzitivity, specificity a přesnosti. Pro extrakci příznaků s cílem klasifikovat kandidáty jako trpící MDD, nebo jako zdravé, byla použita EEG data s otevřenýma očima 31 kandidátů trpících depresivní poruchou (MDD) a 28 zdravých kandidátů. Byly otestovány dva algoritmy, NSGA-II a NSGA-III. Navržený algoritmus pracoval se třemi kritérii, ale byly přidány dvě další kritéria - senzitivita a specificita. NSGA-III byl v tomto případě účinnější a byl použit v následujících experimentech. Byla zavedena omezení pro zlepšení parametrů a byly vyzkoušeny různé hodnoty pro pravděpodobnost mutace a křížení. Vygenerované klasifikátory dosáhly průměrné přesnosti 91.36 \%, senzitivity 91.82 \% a specificity 90.84 \%. V závěrečných experimentech byly nejčastěji používány kanály F3 a C3 a nejčastěji využívaným vlnovým pásmem byla gama frekvence. Výsledkem této práce jsou efektivní klasifikátory, které byly získány pomocí navrženého algoritmu, jenž využívá genetický algoritmus pro optimalizaci parametrů.
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Variability of spinopelvic alignment in human evolution
Mrázková, Karolína ; Rmoutilová, Rebeka (advisor) ; Hora, Martin (referee)
Spinopelvic alignment is caudal part of spine and pelvis, its sagittal geometry keeps stability of upright posture and bipedal locomotion. The aim of this bachelors thesis is to describe factors which influence spinopelvic parametres and to summarize main changes of spinopelvic alignment in the human evolution. Although during ontogenesis spinopelvic alignment is formed by acquisition of upright posture and bipedal locomotion, it is very variable in modern human and some parameters stay relatively plastic whole life. It enables to keep biomechanically useful geometry of spinopelvic alignment and to compsate factors which influence spinopelvic alignment. During evolution of hominins spinopelvic alignment changed in context of using bipedalism. It seems that there were exceptions which suggest that there was not just one adaptive way to upright posture and bipedalism.
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