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High-Level Petri Nets Interpreter in Python
Grigorev, Danil ; Kočí, Radek (referee) ; Janoušek, Vladimír (advisor)
This work is targeting a goal of implementing a high level Petri net interpret in Python. The implementation is based on SNAKES library. The final product is capable of executing and visualising Petri nets, created by user. The simulator is based on distributed systems theory and is executed in real-time. The end user is able to experience a simple and human-friendly API, made for creation and execution of High-Level Petri Nets.
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Response to dangerous animals in Europe and Africa - attention and emotions
Štolhoferová, Iveta ; Frynta, Daniel (advisor) ; Telenský, Petr (referee) ; Burda, Hynek (referee)
The focus of this thesis on the emotions elicited by certain animals and the attentional bias towards these animals in two completely different human populations - the Czech Republic and the Republic of Somaliland. Animals have long been at the center of human interest, yet our knowledge of what emotions animals evoke is surprisingly incomplete, especially outside of the so-called WEIRD societies. We found that snakes, scorpions, and large carnivores elicited the greatest fear in Somalis. Among Czechs, however, spiders were also among the most feared animals. Both populations were the least afraid of beetles and grasshoppers. Spontaneous attentional bias during free viewing of two simultaneously presented images reflected both this cross-cultural difference and agreement. When a scorpion and a spider were presented together, the Somalis looked significantly more at the scorpion, but the Czechs distributed their attention more evenly between the two animals, although a slight bias in favor of the scorpion was apparent. In contrast, when the grasshopper was presented with a spider or a scorpion, both Czechs and Somalis looked much less at the grasshopper. In the case of snakes, a stimulus highly feared by both Somalis and Czechs, we focused on the effect of the threatening posture on the spontaneous...
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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.
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Factors influencing worldwide zoo collections of lizards, snakes, turtles and crocodiles: effect of conservation status, body size and their attractiveness to humans
Janovcová, Markéta ; Landová, Eva (advisor) ; Komárek, Stanislav (referee)
There is a large number of species existing in the world; each year, however, the number of the endangered ones rapidly increases. Nowadays, captive breeding becomes an option for their survival in refugees. Sufficient population with satisfactory breeding management gives hope for survival to the endangered species (in mid-term) or even possible future reintroduction to their natural habitat. WAZA is currently the world's leading association of worldwide zoos and similar breeding facilities. Because these institutions operate as a network to facilitate the exchange of reared individuals, for conservation purposes, their captive populations may be seen as one large population characterized by its size, i.e., the total number of individuals. Such view is currently recognized by many conservationists as the so-called concept of Noah's Ark. The space on the Ark is limited, therefore it is needed to heed the characteristics of the species aboard to maximize the conservation potential. Many factors influence the presence of species in zoological gardens. Following previous studies we selected some factors that may be important, i.e., body lenght, taxonomy, and IUCN status. Analysis of these factors among the main reptile clades shall reveal the pattern of reptile composition in worldwide zoos. One of the factors...
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Ecological Effects of Climate Change on Snakes
Veverková, Barbora ; Sedláček, Ondřej (advisor) ; Frýdlová, Petra (referee)
Climate change is currently one of the biggest threats that animal species must face. Increasing temperatures cause declines in wildlife populations all around the world. Ectothermic animals might be amongst the most threatened organisms by climate change due to their ecology that makes them dependent on ambient temperature. As ectotherms, snakes will most likely need to adapt to new climatic conditions, or they become extinct. To escape raising temperatures and decreasing precipitation, snakes might shift their ranges and move into more suitable areas. However, snakes have a low dispersal ability, which might lead to range reduction and in some populations even extinction. Climatic changes might affect health and behaviour of snake species as well. Increased temperatures can alter incubation period and embryonic development. Alterations in embryonic development and reduction of incubation period can cause different kinds of malformations, especially in oviparous snakes. These malformations can negatively impact fitness, depending on their severity. Some snake species might also benefit from climate change. Elevated temperatures allow snakes to be more active and, in some cases, even shorten hibernation duration. Snakes are also able to better escape predators in high temperatures than in low...
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High-Level Petri Nets Interpreter in Python
Grigorev, Danil ; Kočí, Radek (referee) ; Janoušek, Vladimír (advisor)
This work is targeting a goal of implementing a high level Petri net interpret in Python. The implementation is based on SNAKES library. The final product is capable of executing and visualising Petri nets, created by user. The simulator is based on distributed systems theory and is executed in real-time. The end user is able to experience a simple and human-friendly API, made for creation and execution of High-Level Petri Nets.
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Evolution of sex determination and sex chromosomes in snakes
Charvát, Tomáš ; Kratochvíl, Lukáš (advisor) ; Šmíd, Jiří (referee)
Snakes form with almost 3700 described species more than one third of all squamate reptiles. The vast majority of snake species belong to the group Caenophidia, which is the best explored group of snakes for sex chromosomes. In contrast, sex chromosomes of the two other groups of snakes - Scolecophidia and Henophidia have so far been paid little attention. All snakes studied so far possess genotypic sex determination. Representatives of all Caenophidian families were observed with a female heterogamety sex determination system (ZZ/ZW) and it was widely accepted that this system was common to all snakes. This claim was recently refuted when a male heterogamety (XX/XY) was confirmed in a python (Python bivittatus) and a boa (Boa imperator), two representatives of Henophidia. In Henophidia, besides the XX/XY system, the ZZ/ZW system was reported in the only known representative of this group with heteromorphic sex chromosomes - A. sp. cf. dumerili. Sex chromosomes or sex determination systems are unknown in Scolecophidia. Caenophidian heteromorphic sex chromosomes have enabled the study of the phenomena associated with the gradual differentiation of sex chromosomes. These include W chromosome degeneration, the accumulation of repetitive elements, the fast Z phenomena, gene dosage compensation, and...
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Evolution of sex chromosomes and karyotypes in snakes
Augstenová, Barbora ; Kratochvíl, Lukáš (advisor) ; Majtánová, Zuzana (referee)
Snakes (Serpentes) are a group of squamate reptiles (Squamata) including more than 3600 species. The vast majority of snakes are from the group Caenophidia, which includes approximately 90% of all extant snake species and represents the most studied lineage. Squamate reptiles are variable in sex determination and genome organisation, however, caenophidian snakes are quite stable in these respects. The typical - and probably ancestral - snake karyotype is composed of 36 chromosomes with 16 macro- and 20 microchromosomes. In all snake species, genotypic sex determination (GSD) is expected and it was assumed until recently that all snakes possessed ZZ/ZW sex chromosomes. The main reason for this is that most of the studied snakes were from the group Caenophidia and in the rest of the snake lineages it was believed that their sex chromosomes were homologous. In fact, the sex chromosomes of non-caenophidian snakes have not yet been identified - with the single exception of Acrantophis dumerili. Nevertheless, a recent study showed that there was an independent evolution of XX/XY sex chromosomes in pythons and boas. Sex chromosomes of these snakes are homomorphic and so far they have not been detected by classical cytogenetic methods. In this context, the aim of this study is to explore whether it is...
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Factors influencing worldwide zoo collections of lizards, snakes, turtles and crocodiles: effect of conservation status, body size and their attractiveness to humans
Janovcová, Markéta ; Landová, Eva (advisor) ; Komárek, Stanislav (referee)
There is a large number of species existing in the world; each year, however, the number of the endangered ones rapidly increases. Nowadays, captive breeding becomes an option for their survival in refugees. Sufficient population with satisfactory breeding management gives hope for survival to the endangered species (in mid-term) or even possible future reintroduction to their natural habitat. WAZA is currently the world's leading association of worldwide zoos and similar breeding facilities. Because these institutions operate as a network to facilitate the exchange of reared individuals, for conservation purposes, their captive populations may be seen as one large population characterized by its size, i.e., the total number of individuals. Such view is currently recognized by many conservationists as the so-called concept of Noah's Ark. The space on the Ark is limited, therefore it is needed to heed the characteristics of the species aboard to maximize the conservation potential. Many factors influence the presence of species in zoological gardens. Following previous studies we selected some factors that may be important, i.e., body lenght, taxonomy, and IUCN status. Analysis of these factors among the main reptile clades shall reveal the pattern of reptile composition in worldwide zoos. One of the factors...
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Reproductive strategies in boid snakes
Vejvodová, Tereza ; Frynta, Daniel (advisor) ; Rehák, Ivan (referee)
The important part of life history of species is number and size of offspring, which is limited by size of maternal investment. Family of boas (Boidae) comprises species with various maternal investments. The species of study was Cuban boa (Chilabothrus angulifer) having small litter size, but producing one of the biggest neonates from family Boidae. The aim of the thesis was to analyze relationships between life-history parameters and try to find possible evolutionary causes of this huge maternal investment. Results show, that the female's decision to reproduce is under "Capital breeder" strategy, when size of the female positively influence litter size and offspring size. Surprising result is that smaller (younger) females are producing more sons than daughters in accordance with "Local resource competition" hypothesis. Fitness of the young should increase with birth size. That was confirmed only in interspecific survival rate being very high in Cuban boa. Keywords: snakes, Cuban boa, maternal investment, life history, SSD, sex ratio
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