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Behaviour and ecology of leopard geckos (Eublepharis macularius)
Jančúchová Lásková, Jitka ; Landová, Eva (advisor) ; Moravec, Jiří (referee) ; Sedláček, František (referee)
During evolution, the natural selection favours individuals with the best survival strategy and the highest reproductive success. From the evolutionary point of view, hybridization plays an important role in the process of speciation. Avoiding predators by choosing the most appropriate antipredator strategy increases the animal's chances of survival as well. Studying fitness consequences of hybridization and predation in Eublepharis macularius (Eublepharidae) was the main objective of this theses. Compared to other vertebrate groups, the reliable records on hybridization and its effect on the hybrid's fitness (fertility, survival) in lizards are scarce, despite their ability to hybridize between genetically distant species. These effects were examined in two species of eyelid geckos (E. macularius and E. angramainyu). We aimed to discover whether they were willing to hybridize with a heterospecific species and how the fitness of the hybrids would be affected. Similarly, were studied more genetically related forms of E. macularius species complex, the potential precopulatory barriers, and fitness cost of this hybridization. Analysis of published data has shown that the lizards hybridize between very phylogenetically distant species and are even "more successful" than birds or turtles. Surprisingly,...
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Positive and negative attitudes towards animals
Peléšková, Šárka ; Landová, Eva (advisor) ; Špinka, Marek (referee)
During the entire course of evolution of our species have animals played an important role in human society and culture. They receive considerably more attention over other stimuli and the interest in animals is accompanied by both positive and negative emotions. This work deals with human attitudes towards three classes of vertebrates - amphibians (Amphibia), mammals (Mammalia), and birds (Aves) - and aims to reveal morphological and other perceptional characteristics of these animals (colour, pattern) that are responsible for their ratings of attractiveness, and of fear and disgust induced, and to investigate the relationship of negative emotions and human aesthetic preferences. The testing, underwent by 536 respondents, revealed the general body shape has the most significant impact on the rating of attractiveness and disgust induced by amphibians. Mammals and birds were significantly influenced by their real body size that was impossible to completely filter out by standardising of the photographs. Colours were of merely marginal influence, saturation contributed to the positive rating, whereas dark and dull colours were rated rather negatively. Particular colours were specific for individual groups. The relations between the examined quantities were not uniform among all the investigated...
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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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Sex reversion in the lizard with genotypic sex determination (Squamata: Acrodonta: Pogona vitticeps)
Ehl, Jan ; Kratochvíl, Lukáš (advisor) ; Landová, Eva (referee)
Sex determination among reptiles is a very variable matter across it's taxa. We meet there temperature sex determination and genotypic sex determination with many independent transitions between them. It is a group suitable to study evolution of sex determination, sex chromosomes and sex determination genes. Rare cases of sex reversal caused by extreme incubation temperature or exogenous hormones have been reported in recent years. In case of Acrodont lizard, Pogona vitticeps, was reported sex reversal caused by high incubation temperatures. Our purpose was to repeat the experiment, mainly due to insufficient conclusiveness of used methods. We wanted to expand the experiment by hormonal reversal, studying persistence of sex reversal to maturity and fertility of reversed individuals. We managed successfully to demonstrate sex reversal in both treatments by histological examination. Individuals with discordant phenotypic and genotypic sex were breed till one year of life, which demonstrate persistence of reversal. Our outcomes are concordant with most recent work on this species and show full functional phenomenon of sex reversal with reptiles, which studying could contribute to our understanding of evolution of sex determination.
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Interaction between animal cognition and animal personality
Houšková, Markéta ; Landová, Eva (advisor) ; Šíchová, Klára (referee)
Personality is an important characteristic of individual variability which in some way restricts the full behavioural flexibility. Generally, it is not known, what is the relationship between environmental variability and variability in cognitive abilities of animals? More specifically, how this relationship impacts on the evolution of behavioural plasticity and the expression of animal personality. It is assumed that there is a correlation between the type of personalities and cognitive abilities but mutual causal relationship of this interaction is not yet fully understood. Proactive types of personalities in cognitive tests seem to be neophilic but slower in adapting to changes in the environment or in the analysing of signals with the changed meaning (reversal learning). On the contrary, reactive types of personalities are probably neophobic, they less risk and they are more flexible. However, it is questionable whether these behavioural types have an influence on cognitive abilities and how this influence manifests itself specifically to them. In this thesis, we will focus on whether and how different types of personalities are reflected in these cognitive abilities for each species and what is the methodology for testing these dependencies. Key words: animal personality, coping style,...
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Evolution of brain size and encephalization in birds
Straková, Barbora ; Němec, Pavel (advisor) ; Landová, Eva (referee)
Vertebrates show dramatic interspecific variation in the size of their brains. Large and complex brains evolved independently in birds and mammals. Despite many fundamental differences in their anatomical organization, recent evidence indicates that extensive regions of the avian cerebrum are homologous to pallial components of the mammalian brain. Birds have brains that are comparable in their relative size to the brains of mammals, and much larger than the brains of non avian reptiles. However, the selection pressures that have driven evolution of avian brains remain poorly understood. Comparative analyses identified various traits such as body size, metabolic rate, maternal investment, parental care, prolonged development, mating system and migratory behaviour as important correlates of relative brain size. By contrast, there seems to be a little evidence that sociality favour the evolution of large brains in birds. It has also been shown that particular behaviours such as song learning or food-hoarding correlate with size of those brain regions that participate in these behaviours. Future studies should not only look for novel determinants of brain size but also include known correlates and utilize path analysis modelling to describe the direct, indirect and spurious dependencies among these...
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Perception of beauty of mammals in Prague ZOO: Influence of respondents' age and education
Poláková, Petra ; Landová, Eva (advisor) ; Komárek, Stanislav (referee)
1 Abstract Every year, the number of species considered as endangered increases, especially due to human activities. Nowadays, captive breeding in zoological gardens becomes an option for their survival in refugees. Zoological gardens function as so-called "Noah's Ark", which has the potential to shelter a large amount of individuals from many species. In the future, this opportunity may give us a chance to reintroduce a species that disappeared in the nature. There are many factors influencing which species will be selected to be kept in zoos, e.g., the IUCN status, taxonomical uniqueness, availability, etc., but it was found that especially the size of the animal and the human aesthetic preferences affect the selection. However, every group of animals is evaluated independently in the terms of beauty, and thus, it is necessary to detect these rules and then to apply them to conservation projects. This thesis examines the factors that influence human aesthetic preferences to mammals, both in terms of the characteristics of animals (their colour and morphology), and in terms of human factors (gender, age, education, residence). It was found that especially the pattern, saturation and overall lightness of the animal affect the evaluation of beauty in mammals. On the other hand, dark colours are evaluated...
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Comparison of individual's performance in a discrimination tasks with respect to the hierarchy status
Kocourková, Zuzana ; Landová, Eva (advisor) ; Veselý, Petr (referee)
The ability to discriminate stimuli is the most tested cognitive task in pigeons (Columbia livia f. domestica) within up to now published experiments. Up to now, the influence of personality traits on discrimination has been poorly studied. This thesis looks into the differences in success between individuals and discrimination tasks, and analyzes factors including personality traits influencing the success rate. In this experiment, the total of 72 individual pigeons were tested in four linked tasks: 1) discrimination of black and white screen in the Skinner's box, 2) discrimination of black and white circle patch in the Skinner's box, 3) discrimination of black and white lid in a cage and 4) discrimination of reduced black and white stimuli, placed on a lid, in the cage. The criterium of success was set on 80%. In the Skinner's box, the task were passed by lower number of individuals (6% in first, 20% in second) in comparsion with the cage (48% in third and 50% in fourth). The tasks differed in environment and size of stimuli. It has been determined, that te tested subjecs were able to generalise in the Skinner's box, with an expception when the stimuli was reduced. While testing, all factors that might have influenced the success rate were observed. It has been proved, that the success rate was...
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Nervous system and cognitive abilities of gallinaceous birds
Zhang, Yicheng ; Němec, Pavel (advisor) ; Landová, Eva (referee)
2. Abstract Avian brain has traditionally been looked upon as a small, simple and almost entirely composed of basal ganglia and subserving exclusively instinctive behavior. In stark contrast to these obsolete notions, recent evidence demonstrates that, despite a lack of layered neocortex, extensive regions of the avian cerebrum are homologous to pallial components of the mammalian brain, conform to the same organizational principles and play similar roles in higher cognitive functions. Indeed, behavioural studies have shown that some birds have cognitive abilities that match or surpass those of mammals, most notably corvids and parrots rivalling the great apes in many cognitive domains. While these highly encephalized birds are often utilized as models in behavioural studies addressing avian cognitive capacities, less encephalized birds receive only scant attention. The gallinaceous birds (Galliformes), which together with the anseriform birds (Anseriformes) represent a sister group of Neoaves and the most basal clade of Neognathae, possess relatively small brains. Their cerebrotype is characterized by small forebrain, small nidopallium and large brain stem. Brain of gallinaceous birds is significantly lateralized. Brains of domesticated galliforms are significantly reduced in comparison to brain of their...
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