National Repository of Grey Literature 50 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
The impact of hierarchy in birds on various parameters of fitness
Oblonská, Aneta ; Landová, Eva (advisor) ; Klvaňová, Alena (referee)
Many birds species live in hierarchically structured flocks. The aim of this thesis is determine how the hierarchy is organized to what and extent the hierarchy influence the fitness of dominant individuals. It is focused on the well explored effects of instrinsic factors such as age, body size and sex as well as on the influence of personality that has been examined in recent years. Advantages of hierarchy can be demonstrated by long-term studies, that observe the stability of the hierarchy. Apparently, dominant individuals are able to inform others about their social status and fighting ability through the signal status, which is an honest signal of overall qualities this individuals. Dominant individuals have significantly higher reproductive success, but the mechanisms may differ and reproductive success can achieved through indirect correlations of fitness such as priority food access or better territory. But there are some exceptions where dominant individuals do not profit from their social status. Key words: hierarchy, dominance, social systems, fitness, reproductive success
Cognitive abilities in reptiles and relevant research methodology
Polonyiová, Alexandra ; Němec, Pavel (advisor) ; Landová, Eva (referee)
Reptiles are a neglected group in the study of cognitive abilities of Amniota. Due to their phylogenetic relationship with birds and mammals, knowledge about reptile brains and cognition is important to understanding their evolution in other amniote groups. In this thesis, I summarized the literature on cognitive abilities in reptiles, which focuses on spatial orientation, such as orientation based on visual cues or compass navigation, associative learning, mainly visual discrimination and operant conditioning, and social learning. It has been shown that some reptilian species are capable of flexible behaviour and, given the right methodology, can successfully solve a number of cognitive tasks. I also briefly treated the size and structure of reptile brains, providing the neural substrate for these abilities. Keywords: reptile, cognitive abilities, brain size, brain structure, spatial orientation, associative learning, social learning
Evolutionary consequences of species specific learning strategies: importance of processes resulting in food aversion and special case of social transmission
Landová, Eva ; Fuchs, Roman (advisor) ; Komárek, Stanislav (referee) ; Sedláček, František (referee)
t t Summary This PhD. thesis contributesto the investigationof aposematism- the phenomenonexplaining occuÍTenceof warning coloration in nature. Aposematismis anantipredatorystrategyousuallybasedonpredatorlearning to avoid a noxious prey with a conspicuoussignal. However, not only particularaspectsof aposematicprey signalling (waming colour pattern, conspicuousness,unpalatability),but also predator'spsychologyleadingto avoidancebehaviouris animportantfactorin theevolutionof aposematism. The differentialspecies-specificresponseof nine speciesof our conrmon passerine birds to living aposematicprey (the ťrebug) and correspondingunderlyingvariationin predator'secolory requirements has beenstartingpointof thisPhD.thesis. The next partsof the presentthesishavebeenfocusedmainly on determinationof thesespeciesthat respondspositively (throughoutinnate biases,betterlearningor memoryetc.)to the warningsignalof aposematic prey. The diversity of psychological processes leading to avoidance behaviourin thesespecieshas beenassessed.Firstly, we investigateif the avoidancebehaviouris acquiredby learningor ifthe preyis avoidedon the basisof innatebiasesin severalspeciesof family Paridae. Thenwe focused onmodeof avoidanceleaminganddurabilityof acquiredbehaviourin model species(greattits).The changesin memoryfor...
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,...
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...
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...

National Repository of Grey Literature : 50 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.