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Eocrinoid echinoderms from mid-Cambrian of the Barrandian area
Nohejlová, Martina ; Fatka, Oldřich (advisor) ; Mergl, Michal (referee) ; Valent, Martin (referee)
This thesis deals with the topic of eocrinoid echinoderms from the Barrandian area (Příbram- Jince Basin, mid-Cambrian, Drumian). The thesis is presented as a compilation of five published papers and an introduction. The introduction is an overview of current knowledge about eocrinoid echinoderms. It also includes links to new information from the five included papers, and serves as a unifying element for these professional publications. The topic of the thesis is focused on a revision of selected specimens of eocrinoid echinoderms, and the study of their ontogeny, phylogeny, palaeoecology and systematic position. This thesis has also improved our understanding of early evolution of basal blastozoans. This is the first study of Cambrian ontogenetic development on eocrinoid material from the Czech Republic. Complete ontogeny was described on the genus Akadocrinus, and it was possible to establish two basic phases in the development of this genus: pre-epispire-bearing phase and epispire-bearing phase. The new primitive blastozoan Felbabkacystis is described from the Jince Formation - its unique body plan highlights evolution of the body wall among blastozoans. Palaeoecology and phylogeny of the genus Vyscystis was studied, and phylogenetic analysis suggests a basal position of lepidocystoids among...
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Study on dynamics of spinning apparatus of some wolf spiders (Araneae: Lycosidae) during their life cycle
Dolejš, Petr ; Smrž, Jaroslav (advisor) ; Žďárek, Jan (referee) ; Hajer, Jaromír (referee)
Current knowledge of the spinning apparatus comes namely from studies on orb web spiders and their relatives, whereas that of wolf spiders were more or less neglected. Therefore, developmental changes of the spinning apparatus of four wolf spiders were studied throughout their life cycles. Each of these lycosids possesses stenochronous life cycle with similar number of instars (7-10) but of different length (1-3 years). There is only one period of reproduction in spring/summer in all four species. Sperms are being formed just after the final moult; diplotene in some species is peculiar. The courtship behaviour reflects the microhabitat occupied by the concrete spider species; the copulations are species specific. Ontogeny of the spinning apparatus of developing spiderlings was observed: The spinning apparatus initiate its function in the first instar. Secondary ampullate, all piriform and all but four aciniform glands are tartipore-accommodated; they do not moult in situ. The tartipores, vestigial structures corresponding to spigots of the previous instar, appear on the spinning field starting with the second instar. Tartipore-accommodated glands play roles also during proecdysis and their evolution corresponds with the way how do the spiders secure themselves when moulting. Hence, the not yet...
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Ontogenetic changes in antipredator defence strategies
Schusterová, Zoe ; Exnerová, Alice (advisor) ; Šípek, Petr (referee)
Changes in antipredatory strategies are a timely topic because they help us understand the benefits and limitations of each strategy. They can also help explain certain behaviors of animals at a given ontogenetic stage. My thesis summarizes the existing knowledge on this phenomenon. The first chapter provides an overview of taxa in which the change of antipredatory strategy during ontogeny has been described. I then focus on the antipredatory mechanisms subject to change. I then present hypotheses explaining the origin of antipredatory strategy change and the benefits it confers on animals. Finally, factors that may influence strategy change are discussed. Keywords: antipredatory strategy, predation, aposematism, crypsis, mimicry
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Early ontogeny of the cell's circadian clock
Knapová, Adéla ; Sumová, Alena (advisor) ; Vácha, Martin (referee)
This thesis focuses on the development and function of the circadian system, which regulates biological processes in the body according to the 24-hour cycle. The circadian system and its key components, including the suprachiasmatic nuclei of the hypothalamus and peripheral oscillators, are introduced. The molecular operation of the circadian clock, which is influenced by two loops, is also discussed. A major theme is the ontogeny of the circadian clock, which occurs autonomously during embryonic stem cell differentiation. This process is influenced by various factors such as ultradian rhythms of the segmentation clock and the influence of maternal factors. However, not all signals are essential for the development of these clocks, and especially their rhythms, as revealed by in vitro methods. Furthermore, the thesis discusses how the behaviour of embryonic stem cells differs from cells differentiated from them, and why the circadian clock is dysfunctional in these cells. The work provides a deeper understanding of the ontogeny of the circadian system, its rhythms, and its regulatory mechanisms - that is, when, where and under what circumstances the clock starts to form and "tick".
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The influence of maternal care on the development of the circadian clock during ontogeny
Straková, Lucie ; Sumová, Alena (advisor) ; Spišská, Veronika (referee)
This bachelor thesis focuses on the importance of maternal care in early ontogeny on the development of circadian rhythms and further physiological development. The central clock oscillator (SCN) is most strongly synchronized by the external environment through the rhythms of light and dark. However, during ontogeny, when the main and peripheral oscillators first develop, maternal signals are the main synchronizers for the offspring. Thus, integration between mother and offspring is fundamental to the proper synchronization of the developing offspring's circadian clock, and the mother, through her behavior, can negatively or positively influence its setting. Attention is therefore paid to breastfeeding as a nowadays neglected factor of motherhood that has a strong influence. The composition of breast milk has proven beneficial effects over artificial diets, and breastfeeding has benefits for the health and circadian rhythm of mothers and their offspring. Premature infants are exposed to artificial conditions and weaned from maternal care, similar to offspring in cross-foster experiments. The observation of these effects on the development of their circadian rhythms again only confirms the importance of maternal care. Key words: maternal care, circadian rhythms, ontogeny, breastfeeding
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Ontogeny of neural mechanisms of episodic memory
Šafová, Lucie ; Nekovářová, Tereza (advisor) ; Blahna, Karel (referee)
Two brain structures in particular - the hippocampus and the prefrontal cortex (PFC) - are essential for episodic memory, the ability to recall personal experiences with details of time, place, and event. It is their developmental changes that contribute significantly to the progressive development of episodic memory. The hippocampus is a complex structure composed of several subregions that is crucial to the function of the neural basis of episodic memory. Findings show that both neuronal changes within the hippocampus and changes in its volume and the volume of hippocampal subfields influence episodic memory. As in the hippocampus, changes in the prefrontal cortex also affect episodic memory, with the PFC being among the last regions to fully mature and affecting the accuracy of recalling contextual details of episodic memories. The transfer of information between brain regions is also crucial for episodic memories, and is provided by white matter connections (fornix, cingulum, uncinate fasciculus). This thesis summarizes the knowledge about the structures and mechanisms involved in the development of episodic memory and mentions the factors that influence its development. Keywords: episodic memory, ontogeny, hippocampus, prefrontal cortex, synaptic plasticity
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triggers of asexual reproduction: on the crosslink between hybridization, asexuality, polyploidy and speciation on example of Cobitidae loaches
Marta, Anatolie ; Janko, Karel (advisor) ; Arai, Katsutoshi (referee) ; Trachtulec, Zdeněk (referee)
(in English) Sexual reproduction is considered a nearly universal feature of all eukaryotic organisms and has been hypothesized to be their ancestral state. Sexual reproduction is mainly represented by meiotic division, recombination, production of haploid gametes and fertilization. Although molecular and cytological mechanisms underlying meiosis are highly conservative they may be disrupted in numerous ways leading to the emergence of so-called asexual lineages. The proximate origins of asexuality may differ for particular taxa. In vertebrates, asexuality frequently is triggered by interspecific hybridization. Nowadays "classical" theories predict that asexuals should not be able to persist on a long-term evolutionary scale. However, the hybrid lineages have to overcome short-term disadvantages, such as postzygotic barriers ranging from complete hybrid sterility to altered meiosis resulting in asexual reproduction and even ploidy elevation. Despite that hybrid sterility is one of the most common outcomes of interspecific hybridization, however various lineages found their ways to alleviate these problems and produce viable clonal gametes. The knowledge about proximate mechanisms of unreduced gamete formation in asexual lineages is very limited as many studies were restricted due to methodological...
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Using games and contests in English language teaching at elementary school level.
NOVOTNÝ, Kryštof
Abstract This Diploma Thesis deals with using games and competitions in teaching of English for the first level of primary schools. The aim of the thesis is to characterize the role of the game in English language teaching and its possible use in order to develop key language skills. The theoretical part deals with the psychological characteristics of the younger school age, then the theory of play and the developmental stages of children's play. In the last part of the thesis, there are described the different types of didactic games. The practical part consists of two parts. The first part presents didactic games, that are properly commented in terms of general educational and language objectives. Each of them was taught and reflected in terms of its effectiveness. The second chapter of the practical part presents the results of the research, which was conducted in the form of a guided interview with English language teachers at the elementary school, dealing with their experience in using English language lessons at primary school.
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Ontogeny of soldier behaviour and its polyethism in termites
Homolka, Petr ; Šobotník, Jan (advisor) ; Frouz, Jan (referee)
The presence of soldier caste is an important synapomorphy of group Isoptera. The adaptation of this caste to defense tasks is more than obvious and some of their morphological or even behavioral adaptations can be quite impressive. The polyethism in termites is relatively well known inbetween rather worker caste. If there are such a studies pointing at polyethism in soldiers, they are connected with soldier polymorphism. The morphological differences are of course important stimulus to role separation. The goal of this thesis was to examine the polyethism in the species of the termite with monomorphic soldiers - Prorhinotermes simplex. I did behavioral experiments with it in enclosed arenas, recorded on specific days. The data shows, that there are differences inbetween individuals and it would be benefical to invest further time to subsequent studies. The thesis bring out new point of view to defensive behaviour of termites and suggests, that even termite species without polymorphic species may have soldiers with different tasks. Besides I managed to map ontogeny of soldier behaviour in the first two weeks after moulting from presoldier instar. Key words: Isoptera, polyethism, soldiers, ontogeny, defensive behaviour Powered by TCPDF (www.tcpdf.org)
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Factors influencing intraspecific scaling of metabolic rate
Trubelová, Zuzana ; Starostová, Zuzana (advisor) ; Storch, David (referee)
The relationship between metabolic rate and animal body size of the animal has been studied for more than hundred years. Recently, attention of scientists moved from the interspecific to the intraspecific level. The work focuses on the intraspecific scaling of metabolism. When plotting the metabolic rate against body mass during ontogeny the resulting line often exhibits one or more breaks. Why these breaks (and thus reduction the metabolic rate) occur hasn't been fully explained. It is assumed that can be due to certain factors that affect an individual during development. Some of these factors came from the most famous of several hypotheses attempting to explain the scaling of metabolic rate. These hypotheses include the Metabolic Theory of Ecology (MTE), the Metabolic Level Boundaries (MLB), the Cell model and the Dynamic Energy Budget (DEB) hypothesis. There are several factors that could affect individuals during ontogeny. These include internal factors, which result from the internal processes within the body. These factors are often interrelated with each other in different ways; therefore, it is unlikely to choose only one particular factor which affects metabolic rate. The most frequently studied factors are changes of cell size and changes in the proportion of metabolically active...
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