Candida albicans is a polymorphic yeast that can cause life threatening systemic infections in immuno-compromised individuals. One key attribute of C. albicans that enhances its pathogenicity is the ability to switch morphologies between filamentous and vegetative modes in response to specific environmental conditions. Stressful changes in such cellular conditions commonly cause a rapid inhibition of global protein synthesis leading to altered programmes of gene expression. In Saccharomyces cerevisiae, fusel alcohols signal nitrogen scarcity and induce pseudohyphal growth enabling yeast colonies to spread towards nutrient replete areas. These alcohols also inhibit protein synthesis by targeting the translation initiation factor, eIF2B. eIF2B is the guanine nucleotide exchange factor for eIF2, which supports eIF2-GTP production and represents a key regulated step in translation initiation. eIF2-GTP interacts with Met-tRNAiMet to form the ternary complex which is essential for translation initiation. Fusel alcohols target eIF2B leading to reduced levels of ternary complex and reduced protein synthesis. In Candida albicans, a variety of cell biological and genetic assays suggest that fusel alcohols and ethanol inhibit protein synthesis by targeting the translation initiation factor, eIF2B, and they also induce hyphal/pseudohyphal growth, a process that is associated with pathogenesis in C. albicans. In contrast to fusel alcohols, farnesol, aquorum sensing alcohol, does not appear to impact upon eIF2B activity. Rather, biochemical and mass spectrometric analysis suggest farnesol affects the interaction of the mRNA with the small ribosomal subunit during translation initiation. Further elucidation of the effect of farnesol on C. albicans transcript levels and ribosome association by next generation sequencing gave insight into the genes that are differentially expressed following farnesol treatment. While genes involved inmorphological differentiation were generally repressed, those involved in protein synthesis were upregulated, possibly as an adaptive response to inhibition of protein synthesis by farnesol. Intriguingly, the regulation of these functional categories of genes occurred in a co-ordinated manner at either the transcript level or at the level of ribosome association, but rarely was gene expression regulated at both transcriptional and post-transcriptional levels for the same gene.

This thesis investigates the potential application of a two-dimensional depth-averaged sediment transport and morphological model on a large braided river system and examines its capability to build a computational gravel budget and predict the morphological changes. The Lower Fraser River gravel reach is characterized by an irregularly sinuous single-thread channel split around large gravel bars and vegetated islands, and riverbed aggradation because of gradual gravel deposition over the years, bank hardening and channel confinement. Gravel removal from selected locations is considered as one of the viable management options to maintain the safety and integrity of the existing flood protection system along the reach. Therefore, any gravel removal plan in this reach requires a reliable sediment budget estimation and identification of deposition zones. It is also required to examine the possible future morphological changes with and without gravel removal and to assess its impact on design flood level. The main objective of this study is to build a computational sediment (gravel) budget for the 33 km long gravel reach that extends from Agassiz-Rosedale Bridge to Sumas Mountain near Chilliwack. In this study, a two-dimensional depth-averaged curvilinear mathematical model MIKE 21C was modified and applied to predict the gravel bedload transport and detect the change of morphology for the next 10 years period. A gravel transport formula was coded and added into the MIKE 21C model. Sediment transport code modification and application has been done side by side in a trial and error fashion. This is the first use of a conventional two-dimensional depth-averaged model for the entire gravel reach of the Lower Fraser River within affordable computational effort. The model application was successful in term of gravel budgeting, aggradation and degradation zones identification and long-term morphological change prediction, with some limitations and drawbacks. Further modification and model testing with recent bedload data is recommended. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

>Magister Scientiae - MSc / The infants of smoking mothers (compared to non-smoking mothers) have been shown to have a lower birth mass, a lower brain mass, an increased perinatal mortality rate as well as a predisposition to respiratory abnormalities in later life. Evidence suggests that one of the reasons for the latter is abnormal lung structure due to changes in the connective tissue skeleton. This study evaluated the in vivo effects of maternal nicotine exposure (lmg/kg/day subcutaneously - designated the experimental group), which is equivalent to smoking 32 cigarettes per day, on the connective tissue status of the neonatal (7, 14 and 21 day old) wistar rat lung. The control group received sterile saline as a placebo. The specific aspects investigated were: (1) the morphological changes in lung structure and connective tissue (collagen, elastic tissue and reticulin) distribution by means of light microscopy. (2) the quantities of collagen and Emphysema-like morphological changes are present at all ages. The histochemical appearance of collagen is not affected while reticular fibres appear to be abnormal in structure. On day 7 there appears to be no elastic tissue in the nicotine-exposed lung compared to the control lung. This difference is notelastic tissue in the lung. (3) the ultrastructure of the lung connective tissue skeleton by means of scanning electron microscopy. noticeable on days 14 and 21. Biochemical quantitation indicated that, for the three age groups studied, there was no significant difference in collagen content between experimental and control animals. Elastic tissue was significantly higher in 7 day old experimental lungs than in the control group, contradictory to the results of the histochemical studies. This difference was not significant for 14 and 21 day old lungs Ultrastructural studies of the lung connective tissue skeletons hoed abnormal fibres in the experimental group. Changes included fibre breaks, a beaded appearance of certain fibres and a deficiency in normal fibre arrangement due to the direct or indirect effects of nicotine The effects of nicotine on neonatal rat lung after maternal nicotine exposure is described. The direct mechanisms for these events are still not known but speculation as to this are presented here. Further studies which could explain these mechanisms are also suggested.

MA (Tshivenda) / M.E.R. Mathivha Centre for African Languages, Arts and Culture / See the attached abstract below

Most descriptions of the ostrich oropharynx and oesophagus are superficial and supply little meaningful morphological data. It was therefore the aim of this study to address this deficiency by means of a macroscopic and histological study of this region. The results were supplemented by data obtained by scanning electron microscopy. Macroscopic observations confirmed that in the ostrich the oral and pharyngeal cavities formed a single structure and could not be separated using visual criteria. The most obvious components observed in the roof of the oropharynx were the palate, the choana, the infundibular cleft and the pharyngeal folds, and on the floor, the interramal region, the tongue and the laryngeal mound. The prominent median longitudinal fold running along the palate and the numerous folds in the interrammal region of the floor contained a concentration of Herbst (Pacinian) corpuscles. The ramphotheca forming the rim of the oral cavity carried a sharp tomium along the rostral aspect of the mouth. which would assist the ostrich in tearing off plant material. It was further observed that both the roof and floor of the oropharynx could be macroscopically divided into two regions based on colour differences in the mucosa. The pale rostral regions were lined by a keratinized stratified squamous epithelium whereas the darker, more caudally positioned regions demonstrated a thicker non-keratinised epithelium and, in the case of the roof, a glandular layer. None of the regions of the upper digestive tract sampled revealed structures resembling taste buds and it would appear as if taste plays no role in the selection of food in the ostrich. The presence of large numbers of Herbst corpuscles in the palate may indicate the importance of texture in the selection of food in this species. In addition to confirming the folded nature of the ostrich tongue, this study revealed that the deep pouch formed by the dorsal tongue fold is further subdivided by a smaller secondary fold into dorsal and ventral recesses. The function of this structural adaptation is unclear but the large increase in surface area produced by the folds, and by virtue of the numerous mucous producing glands found in the mucosa, would presumably enhance mucous production and secretion required for ingesting often dry and difficult to swallow plant material. In addition to the tongue, the entire caudal aspect of the oropharynx was well-equipped with glandular tissue. Other adaptations for swallowing food included the presence of a highly folded mucosa in the interramal region which would indicate that the floor of the oral cavity in the ostrich is capable of a certain degree of distension to accommodate the accumulation of food in the oral cavity prior to swallowing. In similar fashion the longitudinal mucosal folds present throughout the oesophagus, as in other avian species, would also allow for distension of this organ when swallowing bulky food items. The pharyngeal folds that lie caudal to and around the opening of the Eustachian tubes in ratites are often referred to as the “tonsils” although no histological information has been presented to support this observation. This study revealed that the pharyngeal folds are filled with masses of diffuse and nodular lymphatic tissue and that epithelial folds emanating from the infundibular cleft and retropharyngeal recess formed tonsillar crypts surrounded by the lymphatic tissue. It has been well documented that in most species of birds papillae are found throughout the oropharynx. Papillae have also been described in ratites, mainly on the tongue and at the caudal aspect of the larynx. Whether the projections observed on the laryngeal mound of the ostrich in this study can be viewed as pharyngeal papillae remains debatable. Likewise, the lingual papillae seen in the ostrich were poorly developed and rudimentary. Compared to other birds, therefore, it is clear that the oropharynx of the ostrich is poorly equipped with papillae. This study confirmed that the hyobranchial apparatus consists of both central and paired caudo-lateral components, the former represented by the paraglossum and fused basihyale and urohyale, and the latter by the ceratobranchiale and the epibranchiale. The most important finding was that the paraglossum of the ostrich consisted of paired caudo-laterally directed cartilages that were connected rostrally to each other by fibrous connective tissue, and which supported the ventro-lateral aspect of the tongue. This information on the paraglossum has not previously been reported. The horns of the hyobranchial apparatus did not pass close to the skull as previously reported but in fact curved downwards away from the skull. The larynx consisted of the cricoid, procricoid and two arytenoid cartilages as is found in birds in general. It can be concluded that the present study, in addition to confirming the basic features of the oropharynx previously described for the ostrich, clarified the contradictory information presented in the literature and also provided new, unreported morphological data, some of which may be important when studying nutrition in these birds. / Dissertation (MSc)--University of Pretoria, 2008. / Anatomy and Physiology / unrestricted

The earliest embryonic stages, because of the simplicity of their organization and cellular structure, are logical starting points for developmental studies of plants as a whole. The zygote and early post-zygote phases of embryonic development are periods of minimum cell form differentiation, if the cells possess a potentially to develop in a number of different ways at any stages in their development, it is in all likelihood at this early date. Becoming more and more specialized with continued growth, they finally form tissues and organs with the capacity for specific functions in the division of labour of the mature plant organization. it was felt that the more specialized the cells became, the less impressionable they would be to the influence of an in-vitro environment. Accordingly, this treatise deals with the culture in artificial medium of the early post-fertilization periods in the embryonic growth of Pinus nigra, var. austriaca, in an effort to discover and assess those factors which influence and govern the embryonic development pattern. The present study was begun in 1951 at the suggestion of Professor N.W. Radforth. I wish to express my appreciation to Professor Radforth for his guidance in conducting my research, without which this investigation could not have been carried out. This work was undertaken as part of a programme which has been assisted through a grant from the Ontario Cancer Treatment and Research Foundation, for which Dr. Radforth is the grantee. / Thesis / Master of Science (MS)

Este trabalho busca entender a diversificação craniana dos macacos do Velho Mundo (Catarrhini) integrando duas abordagens para o estudo da evolução de caracteres complexos: a genética quantitativa e a integração morfológica. A investigação tem três objetivos principais: 1) comparar a magnitude e o padrão das relações entre os caracteres cranianos entre todos os Catarrhini; 2) testar a hipótese de que deriva genética é o único agente responsável pela diversificação craniana; 3) explorar as conseqüências evolutivas da associação entre caracteres. De posse de um banco de dados bastante representativo da diversidade dos macacos do Velho Mundo (39 medidas cranianas de cerca de 6.000 crânios de mais de 130 espécies), gerei as matrizes de correlação e de variância/covariância, que resumem as relações entre os caracteres, e comparei-as entre vários grupos. Comparei-as também a expectativas derivadas de modelos teóricos de evolução por deriva genética, além de simular a ação de seleção natural sobre essas matrizes para observar o comportamento evolutivo dos diversos padrões de associação entre caracteres. De maneira geral, o padrão das relações é o mesmo entre todos os Catarrhini, mas a magnitude com que os caracteres estão associados varia bastante. Isso tem conseqüências evolutivas importantíssimas, pois grupos com baixas magnitudes tendem a responder na mesma direção em que a seleção atua (alta flexibilidade evolutiva), enquanto que altas magnitudes estão associadas, independentemente da direção da seleção, a respostas ao longo do eixo de maior variação, que no caso dos Catarrhini corresponde à variação no tamanho (baixa flexibilidade evolutiva). A diversificação inicial do grupo parece ter sido gerada por seleção natural, mas nos níveis de gênero e espécie, deriva genética é o processo predominante; a exceção são os cercopitecíneos, onde há evidência de seleção também nesses níveis. Com base nesses resultados, proponho um modelo que associa a magnitude geral da correlação entre caracteres aos possíveis caminhos evolutivos que uma população pode seguir. Apesar de este trabalho estar empiricamente restrito aos macacos do Velho Mundo, esse modelo é válido para os mamíferos como um todo e pode ser testado em outros grupos, aumentando nossa compreensão de como a associação entre caracteres afeta a evolução dos seres vivos. / This is a study on the cranial diversification of the Catarrhini, a large group of primates that includes all Old World monkeys and apes, bringing together two approaches to investigate the evolution of complex characters: quantitative genetics and morphological integration. It has three main goals: 1) to compare magnitudes and patterns of inter-trait relationships in the skull among catarrhines; 2) to test the null hypothesis that genetic drift is the sole agent responsible for cranial diversification; 3) to explore the evolutionary consequences of inter-trait associations. With a large and representative cranial database of Old World monkeys and apes (39 measurements of around 6,000 skulls from more than 130 species), I generated and compared correlation and variance/covariance matrices, which summarize inter-trait relationships, among several Catarrhini groups. I compared some of those matrices to expectations derived from theoretical models of evolution through genetic drift, and simulated natural selection to observe the evolutionary behavior of each matrix. From a broad perspective, the patterns of relationships are the same among all catarrhines, but the magnitudes are quite variable. This has very important evolutionary consequences, because groups with low overall magnitudes tend to respond in the same direction of selection (high evolutionary flexibility), while higher magnitudes, regardless of the direction of selection, are associated to responses along the axis of highest variation, which in this case corresponds to size variation (low evolutionary flexibility). The initial diversification of catarrhines seems to have been generated by natural selection, but drift probably played a major role at the genus and species level; the exception are the cercopithecines, for which there is evidence for selection also in those levels. Based on these results, I propose a model that links the overall magnitude of inter-trait correlations to the possible evolutionary paths of a given population. This study is empirically restricted to Old World monkeys and apes, but the model has been proved valid to a broader sample of mammals and can be tested for other groups, contributing for our understanding of how complex characters evolve.

No presente trabalho utilizo as abordagens de genética quantitativa e integração morfológica para compreender a evolução do crânio em morcegos da Família Phyllostomidae. Esses morcegos exibem uma diversidade de especializações alimentares que não encontra precedentes dentre os demais mamíferos, havendo atualmente formas envolvidas na insetivoria, hematofagia, nectarivoria, carnivoria, omnivoria e frugivoria. Neste trabalho comparo as matrizes de correlação e covariância fenotípicas que quantificam a associação entre caracteres que descrevem o crânio entre espécies de filostomídeos, com o objetivo de investigar se há similaridade estrutural entre elas. Além disso, exploro possíveis fatores que podem afetar a sua estabilidade, como a história evolutiva (filogenia), dieta e as associações funcionais e de desenvolvimento entre os caracteres cranianos. Por fim, investigo a presença de módulos nos crânios dos filostomídeos e avalio as consequências evolutivas dos padrões e das magnitudes de integração na evolução desse grupo. A base de dados compreende 35 medidas cranianas de 2665 indivíduos, abrangendo todas a subfamílias, e representando ao todo 48 espécies e 45 gêneros. Os resultados indicam que após um período de diversificação evolutiva de aproximadamente 33.9 milhões de anos, a estrutura fenótipica de variância/covariância se manteve até certo ponto similar entre as espécies de morcegos filostomídeos. Enquanto os padrões estruturais das matrizes de correlação e covariação permaneceram relativamente similares, a magnitude geral de integração se mostrou evolutivamente mais plástica entre as espécies. Os caracteres cranianos que mais divergiram entre as matrizes estão relacionados às regiões do crânio que expressam grande variação morfológica qualitativa e estão diretamente relacionadas aos hábitos alimentares das espécies. A independência entre a distância filogenética e a similaridade estrutural das matrizes de variância/covariância indica que as mudanças e as manutenções dos padrões de covariância são, até certo ponto, dissociados da história evolutiva do grupo. Por outro lado, mudanças nas estruturas de correlação e covariância fenotípicas estão associadas à dieta do grupo. Embora dieta e filogenia estejam relacionadas, estes fatores diferem quanto a sua associação (e potencial causalidade) com a evolução tanto do fenótipo médio quanto da estrutura de correlação entre os caracteres do crânio. A dieta mostrou um ajuste melhor do que a filogenia para as matrizes de correlação, e para as matrizes de distância morfológica. Além disso, os resultados demonstram que os filostomídeos compartilham padrão de modularidade craniana relacionado à função e desenvolvimento, e os resultados corroboram a organização modular encontrada em outras linhagens de mamíferos. Em geral, as subregiões oral, nasal e a abóbada craniana aparecem como módulos dominantes nos crânios destes morcegos, e um olhar para aspectos funcionais e de história evolutiva ajudam a compreender os padrões de integração morfológica desse grupo tão diverso e intrigante. Nem todas as espécies de filostomídeos estudadas aqui apresentaram variação associada ao tamanho no primeiro componente principal da matriz de covariância. Mesmo não sendo tamanho, esse componente ainda assim age como uma restrição à evolução. Esse resultado é evidente nos valores de correlação altos e significativos entre os índices de magnitude geral de integração e o primeiro componente principal, e das correlações entre o primeiro CP e os índices de flexibilidade e restrição. Espécies que apresentaram alta magnitude geral de integração entre os caracteres do crânio possuem menor capacidade de evoluir na direção da seleção, sendo portanto mais restritas evolutivamente. Espécies de filostomídeos que apresentam asssociações mais baixas nos caracteres cranianos apresentam maior flexibilidade evolutiva, ou seja, maior capacidade em responder na direção em que a seleção está atuando / Here I use a quantitative genetics and morphological integration approaches to understand the evolution of bat skulls of the Phyllostomidae family. These bats display an unprecedented diversity in terms of dietary specialization that is unique in mammals, with insectivorous, hematophagous, nectarivorous, carnivorous, omnivorous and frugivorous species. In this thesis, I compare the covariance and correlation phenotypic matrices, which are a quantification of the relationship among skull traits, in order to investigate whether there is structural similarity between them. Furthermore, I explore possible factors that may affect its stability, such as evolutionary history (phylogeny), dietary habits and functional and developmental associations between cranial traits. Finally, I investigate the presence of modules in the skulls of phyllostomids and assess the evolutionary consequences of the patterns and magnitudes of morphological integration in the evolution of this group. The database comprises 35 cranial measurements of 2665 specimens, including all the subfamilies, representing 45 genera and 48 species. The results indicate that after an approximately 33.9 million years period of evolutionary diversification, the phenotypic variance/covariance structure remained, to some extent, similar among species of phyllostomid bats. While the patterns of covariance and correlation matrices remained relatively similar, the overall magnitude of integration presented considerable variation between species. The cranial traits that diverged the most between the matrices are related to the regions of the skull that display great qualitative morphological variation and are directly related to the dietary habits of the species. The independence between the phylogenetic distance and the structural similarity of variance/covariance matrices indicates that changes and stasis in covariance patterns are, to some extent, decoupled from the evolutionary history of the group. On the other hand, changes in the phenotypic correlation and covariance structure are associated with the dietary habits of the group. While diet and phylogeny are related, these factors differ regarding their association (and potential causality) with evolution, both concerning the average phenotype divergence, as well as the correlation structure between cranial traits. The diet showed a better adjustment than the phylogeny for correlation matrices, as well as for the morphological distance matrices. Furthermore, the results demonstrate that the phyllostomids share the same patterns of cranial modularity for functional and developmental hypothesis, and confirm the modular structure found in other lineages of mammals. Generally speaking, the oral, nasal and cranial vault subregions appear as dominant modules in the skulls of these bats, and focusing on functional and evolutionary history aspects help to better understand the patterns of morphological integration of this group that is so diverse and intriguing. Not all species of bats that were included in this study showed size variation in the first principal component of the covariance matrix. Even if this first principal component is not size related, this component still acts as an evolutionary constrain. This result is evident in the high and significant correlation values between the overall integration indexes and the first principal component, and regarding the correlation between the first PC and the flexibility and constraint indexes. Species with high overall magnitude of integration between the skull traits have less ability to evolve in the direction of the selection and, therefore, are more evolutionary constrained. Species of bats that exhibit lower associations of cranial traits show greater evolutionary flexibility, i.e., greater capacity to respond in the direction in which selection is acting

Šiame darbe kuriamas įrankis, kuris padėtų nustatyti, kurios morfologinės žymos savybės yra svarbios sprendžiant lietuvių kalbos morfologinio daugiareikšmiškumo problemą. Morfologinio daugiareikšmiškumo problema išsprendžiama tuomet, kai pagal kontekstą vienam žodžiui priskiriama viena morfologinė žyma. Darbe naudojamas tekstynas, kurį sudaro daugiau nei 1.200.000 žodžių. Tekstyne žodžiams morfologines žymas nustatė ekspertas, o visos galimos žodžio morfologinės žymos buvo sugeneruotos su pagalbiniu įrankiu. Morfologinio daugiareikšmiškumo problemoms spręsti suprogramuotas ir taikytas Viterbi algoritmas, randantis tikėtiniausią sakinį atitinkančią kalbos dalių seką pagal sukurtus bigramų ar trigramų kalbos modelius. Atlikus testavimą naudojant dešimt kartų kryžminį patikrinimą, pasiekti toki rezultatai: • 90,10% – tikslumas, kuris parodo ar teisingai priskirta morfologinė žyma daugiareikšmiams žodžiams; • 96,39% – bendras tikslumas, kuris skaičiuojamas įtraukiant ir tuos žodžius, kurie turėjo tik vieną morfologinę žymą. / In this research was developed tool, which helps to determine, which morphological mark attributes are important when solving problem of morphological ambiguity in Lithuanian language. Morphological ambiguity problem is solved, when one word is matched with one morphological mark. Research uses corpus, which contains over than 1.200.000 words. Morphological marks in the corpus were assigned by expert and list of all possible morphological marks was generated with other utility. There was developed and applied Viterbi algorithm to solve morphological ambiguity problem, which finds the most expected path of part of speeches by created bigram or trigram speech models. Testing was implemented using cross validation with 10 folds. There was achieved these results: • 90,10% – accuracy, which shows if morphological mark was correctly match with ambiguous word; • 96,39% – total accuracy, which calculated when included non-ambiguous words.

No presente trabalho utilizo as abordagens de genética quantitativa e integração morfológica para compreender a evolução do crânio em morcegos da Família Phyllostomidae. Esses morcegos exibem uma diversidade de especializações alimentares que não encontra precedentes dentre os demais mamíferos, havendo atualmente formas envolvidas na insetivoria, hematofagia, nectarivoria, carnivoria, omnivoria e frugivoria. Neste trabalho comparo as matrizes de correlação e covariância fenotípicas que quantificam a associação entre caracteres que descrevem o crânio entre espécies de filostomídeos, com o objetivo de investigar se há similaridade estrutural entre elas. Além disso, exploro possíveis fatores que podem afetar a sua estabilidade, como a história evolutiva (filogenia), dieta e as associações funcionais e de desenvolvimento entre os caracteres cranianos. Por fim, investigo a presença de módulos nos crânios dos filostomídeos e avalio as consequências evolutivas dos padrões e das magnitudes de integração na evolução desse grupo. A base de dados compreende 35 medidas cranianas de 2665 indivíduos, abrangendo todas a subfamílias, e representando ao todo 48 espécies e 45 gêneros. Os resultados indicam que após um período de diversificação evolutiva de aproximadamente 33.9 milhões de anos, a estrutura fenótipica de variância/covariância se manteve até certo ponto similar entre as espécies de morcegos filostomídeos. Enquanto os padrões estruturais das matrizes de correlação e covariação permaneceram relativamente similares, a magnitude geral de integração se mostrou evolutivamente mais plástica entre as espécies. Os caracteres cranianos que mais divergiram entre as matrizes estão relacionados às regiões do crânio que expressam grande variação morfológica qualitativa e estão diretamente relacionadas aos hábitos alimentares das espécies. A independência entre a distância filogenética e a similaridade estrutural das matrizes de variância/covariância indica que as mudanças e as manutenções dos padrões de covariância são, até certo ponto, dissociados da história evolutiva do grupo. Por outro lado, mudanças nas estruturas de correlação e covariância fenotípicas estão associadas à dieta do grupo. Embora dieta e filogenia estejam relacionadas, estes fatores diferem quanto a sua associação (e potencial causalidade) com a evolução tanto do fenótipo médio quanto da estrutura de correlação entre os caracteres do crânio. A dieta mostrou um ajuste melhor do que a filogenia para as matrizes de correlação, e para as matrizes de distância morfológica. Além disso, os resultados demonstram que os filostomídeos compartilham padrão de modularidade craniana relacionado à função e desenvolvimento, e os resultados corroboram a organização modular encontrada em outras linhagens de mamíferos. Em geral, as subregiões oral, nasal e a abóbada craniana aparecem como módulos dominantes nos crânios destes morcegos, e um olhar para aspectos funcionais e de história evolutiva ajudam a compreender os padrões de integração morfológica desse grupo tão diverso e intrigante. Nem todas as espécies de filostomídeos estudadas aqui apresentaram variação associada ao tamanho no primeiro componente principal da matriz de covariância. Mesmo não sendo tamanho, esse componente ainda assim age como uma restrição à evolução. Esse resultado é evidente nos valores de correlação altos e significativos entre os índices de magnitude geral de integração e o primeiro componente principal, e das correlações entre o primeiro CP e os índices de flexibilidade e restrição. Espécies que apresentaram alta magnitude geral de integração entre os caracteres do crânio possuem menor capacidade de evoluir na direção da seleção, sendo portanto mais restritas evolutivamente. Espécies de filostomídeos que apresentam asssociações mais baixas nos caracteres cranianos apresentam maior flexibilidade evolutiva, ou seja, maior capacidade em responder na direção em que a seleção está atuando / Here I use a quantitative genetics and morphological integration approaches to understand the evolution of bat skulls of the Phyllostomidae family. These bats display an unprecedented diversity in terms of dietary specialization that is unique in mammals, with insectivorous, hematophagous, nectarivorous, carnivorous, omnivorous and frugivorous species. In this thesis, I compare the covariance and correlation phenotypic matrices, which are a quantification of the relationship among skull traits, in order to investigate whether there is structural similarity between them. Furthermore, I explore possible factors that may affect its stability, such as evolutionary history (phylogeny), dietary habits and functional and developmental associations between cranial traits. Finally, I investigate the presence of modules in the skulls of phyllostomids and assess the evolutionary consequences of the patterns and magnitudes of morphological integration in the evolution of this group. The database comprises 35 cranial measurements of 2665 specimens, including all the subfamilies, representing 45 genera and 48 species. The results indicate that after an approximately 33.9 million years period of evolutionary diversification, the phenotypic variance/covariance structure remained, to some extent, similar among species of phyllostomid bats. While the patterns of covariance and correlation matrices remained relatively similar, the overall magnitude of integration presented considerable variation between species. The cranial traits that diverged the most between the matrices are related to the regions of the skull that display great qualitative morphological variation and are directly related to the dietary habits of the species. The independence between the phylogenetic distance and the structural similarity of variance/covariance matrices indicates that changes and stasis in covariance patterns are, to some extent, decoupled from the evolutionary history of the group. On the other hand, changes in the phenotypic correlation and covariance structure are associated with the dietary habits of the group. While diet and phylogeny are related, these factors differ regarding their association (and potential causality) with evolution, both concerning the average phenotype divergence, as well as the correlation structure between cranial traits. The diet showed a better adjustment than the phylogeny for correlation matrices, as well as for the morphological distance matrices. Furthermore, the results demonstrate that the phyllostomids share the same patterns of cranial modularity for functional and developmental hypothesis, and confirm the modular structure found in other lineages of mammals. Generally speaking, the oral, nasal and cranial vault subregions appear as dominant modules in the skulls of these bats, and focusing on functional and evolutionary history aspects help to better understand the patterns of morphological integration of this group that is so diverse and intriguing. Not all species of bats that were included in this study showed size variation in the first principal component of the covariance matrix. Even if this first principal component is not size related, this component still acts as an evolutionary constrain. This result is evident in the high and significant correlation values between the overall integration indexes and the first principal component, and regarding the correlation between the first PC and the flexibility and constraint indexes. Species with high overall magnitude of integration between the skull traits have less ability to evolve in the direction of the selection and, therefore, are more evolutionary constrained. Species of bats that exhibit lower associations of cranial traits show greater evolutionary flexibility, i.e., greater capacity to respond in the direction in which selection is acting