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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Morfologické změny obličeje dospělých mužů a žen během stárnutí / Morphological changes of adult human face during aging

Čiháková, Lucie January 2016 (has links)
Processes of biological changes of organism over time distinctly manifest themselves in a face morphology. The present study age changes are observed as shape and size changes of transversal dates of surface 3D virtual models of faces of 443 women and men (22-88 years old) devided into six age groups in decade. Differences in faces among each age group with respect to the sex were investigated and a sexual dimorphism and its gradual progress with the age using methods of geometric morphometrics (coherent point drift - dense correspondence algorithm, principal component analysis, per vertex t-test, shell-to-shell deviation). A significant difference among age categories was observedd both in shape as well as in form of the face. The faces of women and men were becoming wider with age and convexity was decreasing at the same time. A decline of the whole forehead and of the profile of the men's nose was observed, whereas the women's foreheadwas getting bevel due to the decline of the top part and a profile of the nose wasn't changed with the age. On contrary, the men's chin was unvarying with the age, while the women's chin was sliding out foward. There was observed a distinct decline in the front part of a upper jaw with the both sex. It was found out that after the seventh life decade the face gets...
112

Genital variation in moths—evolutionary and systematic perspectives

Mutanen, M. (Marko) 10 May 2006 (has links)
Abstract genital characteristics have peculiar morphological patterns. They show great divergence between species. At the same time, they are assumed to vary little within species by taxonomists who frequently use genital features to delimit species. I studied moth (Lepidoptera) genital size and shape variation within and between species. I also tested hypotheses proposed to explain rapid genital diversification among species. Studies were carried out using traditional distance measurement morphometrics and modern geometric morphometrics. Several moth species were analyzed. d that genital structures show variation that in closely related species may show structural overlap. More surprisingly, the amount of variation in internal genitalia was equal to non-genital traits. These and some other findings are against the predictions of the lock-and-key hypothesis, which suggests that genital differences form a mechanical isolation system between species. Meanwhile, the findings are in good accordance with the various mechanisms of the sexual selection hypothesis. I found that external genital traits express varying amounts of variability. However, both external and internal genitalia consistently show small variation in size so that large individuals have disproportionately small genitalia and vice versa. This finding is consistent with the lock-and-key theory, but also with the cryptic female choice hypothesis. In conclusion, the results suggest that sexual selection plays a major role in genital diversification, but the exact mechanism remained unclear in this study. Some structures in moth genitalia strongly suggest that sexual conflict is present as well. It is possible that several mechanisms of sexual selection are in action simultaneously. dings have implications to insect taxonomy. Genital characters, although often useful, should not be considered superior to other characters because they may vary considerably within species. I have shown that subjective visual evaluation of genital characteristics and a priori assumption of their low variability may easily lead to unsound taxonomic conclusions. Sophisticated morphometric tools are very useful and objective in delimiting sibling species. Geometric morphometrics is particularly useful since it helps to evaluate limits of variation. There are, however, no theoretical grounds to assume that genitalia are not subject to intraspecific geographic variation. Such variation was detected in this study as well. Geographic relationships should therefore be taken into consideration more frequently when delimiting populations into different species.
113

The Form-Function relationships in the process of secondary adaptation to an aquatic life : the contribution of semi-aquatic mammals / La relation forme-fonction dans le processus secondaire de retour à la vie aquatique : la contribution des mammifères semi-aquatiques

Botton, Léo 16 June 2017 (has links)
Se déplacer dans l’eau ou sur terre implique de faire face à des contraintes mécaniques extrêmement différentes. L’eau est sensiblement plus dense et visqueuse que l’air et, par le fait, la locomotion aquatique est dominée par la traînée et la poussée d’Archimède alors que la locomotion terrestre est dominée par la gravité et l’inertie. Si les adaptations les plus extrêmes à la locomotion dans chacun de ces milieux sont bien documentées, les espèces semi-aquatiques qui se déplacent fréquemment dans ces deux milieux restent peu étudiées.Les mustélidés présentent une large diversité de spécialisations locomotrices tant du point de vue du type de milieu fréquenté que du point de vue du degré de spécialisation.Cela inclut trois événements indépendants d’apparition d’un mode de vie semi-aquatique avec pour représentants actuels : le vison d’Europe, le vison Américain et les loutres. En utilisant la morphométrie géométrique pour quantifier l’ensemble de la forme de l’humérus, du radius, de l’ulna, du fémur, du tibia et de la fibula, j’ai étudié les différences morphologiques de l’appareil locomoteur des mustélidés terrestres et semi-aquatiques. Étant donné que les visons et les loutres font face aux mêmes contraintes fonctionnelles liées à une locomotion à la fois terrestre et aquatique, j’ai testé si leur morphologie convergeait. Enfin, étant donné la différence de contraintes fonctionnelles induites par les deux milieux, j’ai testé si le milieu de locomotion avait un impact homogène sur l’appareil locomoteur ou si une spécialisation de certains os pouvait être observée.Si les visons diffèrent peu de leurs parents terrestres, les loutres montrent d’importantes différences en termes de taille, forme et proportions relatives des os. Les visons présentent une morphologie similaire à celle observée chez tous les Mustelinae.Néanmoins, la morphologie de l’humérus est convergente entre les deux visons, avec une courbure plus grande que chez leurs parents terrestres. La morphologie des visons résulte de spécialisations récentes de la morphologie versatile propre aux Mustelinae, leur mode de nage est similaire à celui des Mustelinae terrestres et ils ne montrent que de subtiles différenciations morphologiques.A l’opposé, les loutres présentent des os longs dont la forme diffère nettement de celle de leurs parents terrestres. De plus, elles montrent une grande diversité de formes, en opposition avec l’hypothèse qui voudrait que de fortes contraintes fonctionnelles, telles que celles induites par la locomotion aquatique, devraient conduire à un nombre limité de réponses évolutives possibles. Les loutres montrent un ensemble de caractéristiques morphologiques en lien avec la locomotion aquatique: des os robustes, avec de larges épiphyses, un stylopode court relativement au zeugopode et un grand bras de levier pour les extenseurs du coude. Seule la loutre de mer (Enhydra lutris) montre une spécialisation différente entre les pattes avant et arrière. Les pattes arrière sont dédiées à la locomotion aquatique avec un grand bras de levier pour les muscles de la hanche et un pied transformé en palette natatoire. La patte avant, en revanche, présente une ulna gracile, avec un processus olécrane court et un radius courbé cranialement, produisant un patronde co-variation unique. Ces particularités permettent de plus grands degrés de liberté dans les mouvements de l’avant-bras, et de fait, les capacités de manipulation uniques chez cette espèce.Ainsi les mustélidés semi-aquatiques présentent une diversité qui n’était pas attendue étant donné la différence de contraintes mécaniques imposées par la locomotion dans l’eau et sur terre. Les mustélidés semi-aquatiques semblent avoir évolué depuis une morphologie ancestrale versatile jusqu’à des formes très spécialisées,où la réduction progressive de la locomotion terrestre a permis une spécialisation différente entre les membres antérieurs et postérieurs. / Moving in water and on land implies coping with drastically different mechanicalconstraints. Water is substantially more dense and viscous than air and thus aquaticlocomotion is dominated by drag and buoyancy when terrestrial locomotion is dominatedby gravity and inertia. If extreme adaptations to locomotion in each of thesetwo media are well described, semi-aquatic species that move extensively in bothmedia remain poorly studied.Mustelids presents a large diversity of locomotor specializations involving differentkinds of locomotor environments and different degrees of specialization. It encompassthree independent evolutions of a semi-aquatic lifestyle: the European mink,the American mink, and the otters. Using geometric morphometrics to quantify theshape of the entire humerus, radius, ulna, femur, tibia, and fibula I investigated morphologicaldifferences in the locomotor apparatus of terrestrial and semi-aquaticmustelids. As both minks and otters face functional pressures resulting from bothaquatic and terrestrial locomotion, I tested whether their morphology converged.Finally, considering the differences in the functional requirements of the two media,I explored whether the locomotor ecology has a homogeneous impact on thelocomotor apparatus or whether a functional specialization of certain parts can beobserved.Whereas minks show low morphological differentiation from their terrestrial relatives,otters diverged a lot in both shape, size, and the relative proportions of thelimb bones. Minks present a morphology that is similar to the one observed in otherMustelinae. Nevertheless, the shape of the humerus is convergent between thetwo minks, and shows a greater curvature than in their terrestrial relatives. Minksresult from recent specializations of the versatile morphology of Mustelinae witha swimming mode similar to the one of the terrestrial Mustelinae and only subtlemodifications of their long bone morphology.Conversely, otters present a long bone shape that is strongly divergent from theone of their terrestrial relatives. Additionally, they show very diverse long boneshapes in opposition to the hypothesis stating that strong functional requirements,as the ones induced by aquatic locomotion, should induce a limited number of potentialevolutionary responses. Otters show morphological features that are related to aquatic locomotion: robust bones with broad epiphyses, a short stylopodrelative to the zeugopod, and a long in-lever for elbow extensors. Only the sea otter(Enhydra lutris) presents a functional specialization that differs between hind andforelimb. The hind limb is dedicated to aquatic locomotion with a strong in-lever forthe hip muscles, and the feet that are modified into swimming paddles. Meanwhile,the forelimb presents a relatively gracile ulna with a short olecranon process and aradius that is curved more cranially, resulting in a drastic change in the pattern ofco-variation. These features are interpreted as providing greater degrees of freedomin the movements of the forearm, which allows the unique manipulative skillsof this species.Thus semi-aquatic mustelids present a diversity that was not expected given thestrong differences in the mechanical constraints imposed during locomotion in waterversus on land. Semi-aquatic mustelids appear to have evolved from the versatileancestral locomotor apparatus to highly specialized forms, where the progressivereduction of terrestrial locomotion allowed differential adaptation of the foreandhind limbs.
114

Revize ontogeneze trilobita Sao hirsuta Barrande, 1846 z kambria ČR / Ontogeny of Sao hirsuta (Barrande, 1846) in the Cambrian of Czech Republic: revision

Laibl, Lukáš January 2012 (has links)
The Solenopleurid trilobite Sao hirsuta Barrande, 1846 is known from "Middle" Cambrian sedimentary rocks of the Czech Republic, Germany and Spain. It is one of the first trilobites on which ontogenetic development was described in detail (Barrande, 1852). This diploma thesis is the first modern revision of the ontogeny of this species for more than fifty years. Thesis is primarily based on quantitative methods and a detailed study of morphology of the exoskeleton. Changes in the dorsal exoskeleton during ontogenetic development of S. hirsuta, including the discovery of intrainstar morphological and size variability and the transition from isometric growth to the alometric growth, were described in detail by using quantitative methods (biometric measurements and geometric morphometrics). In the protaspid period different instars of S. hirsuta were recognized. Detailed morphological studies revealed several different morphotypes of protaspid stages. Some of which may represent different taxa. The morphology and the condition of the hypostome was described, including changes of hypostome during ontogeny. The study of segmentation in the species S. hirsuta shows hypoprotomeric development with the initial accumulation phase, middle equilibrium phase and terminal depletion phases. Key words: Sao...
115

Populační a geografická proměnlivost létavců (Miniopterus) v západní Palearktidě / Population and geographic variation in long-winged bats (Miniopterus) in the western Palaearctic

Šrámek, Jan January 2010 (has links)
In this study the sexual and geographical variations in the genus Miniopterus were deeply investigated, using multidisciplinary analysis (morphometric cranial, dental, fenetic and shape analysis; molecular analysis of mt gene ND2). Different populations from western Palearctic and adjacent regions were analysed: Miniopterus schreibersii (Morocco, West Europe, Pannonia, Balkans, Crete, Near East, Middle East), Miniopterus natalensis (Yemen, Ethiopia) a Miniopterus inflatus (Ethiopia). Extensove samples of Miniopterus schreibersii were tested and existence of sexual dimorphism in cranial constitution was showed: males had generally bigger and relatively higher, shorter and narrower skulls than females; female mandibles were generally bigger than the male ones, females showed also more robust and larger teeth than males. On the other hand, males had markedly bigger canines and relatively higher P4 (in relation to other premolares). The sexes also deiffered in shape of P4 and upper molars. According to the interpopulation variation found, Miniopterus schreibersii samples from West Europe, Pannonia, Balkans, Crete, Sicily, Georgia, coastal Turkish and Moroccan areas belong most probably to the subspecies M. s. schreibersii (Kuhl, 1817). The samples from Afganistan, Iran, Azerbaijan, and from localities...
116

Sledování ontogenetického vývoje mandibuly na základě metod geometrické morfometrie / Evaluation of ontogenetic development of the mandible using geometric morphometric methods

Kiebelová, Alena January 2010 (has links)
During ontogeny there are a lot of changes in the entire human skeleton. This thesis deals with shape changes in the mandible, which are caused by genetic, hormonal, as well as mechanical factors. The most important mechanical factors influencing the shape of mandible are development of deciduous and permanent dentition and also development of masticatory muscles. 34 children mandibles of known age and 14 adult mandibles were analysed and compared for this thesis. Data were obtained by scanning coordinates of 36 landmarks using Microscribe G2X, and then were processed by software PAST and Morphologika2 using multivariate statistics (PCA, MANOVA). Geometric morphometrics is used for a detailed analysis of shape changes of the mandible. There is no difference between dental and chronological age. In conclusion, lower jaw narrows during growth, the body extends more in the region of third molars and the ramus grows mainly in the region of condylar process. Chin prominence also occurs during ontogeny. In the group of adult mandibles the variability is caused by coronoid process height and the body width. The hypothesis, that age groups are significantly different from each other, and therefore due to tooth mineralization there are marked shape changes, is confirmed.
117

Brain morphology and behavioural variation in relation to habitat and predation risk in minnows (Phoxinus phoxinus)

Gallego González, Marina January 2022 (has links)
So far, research on inter- and intraspecific teleost brain plasticity across different freshwater environments has been widely conducted. However, insights of brain morphological variation on social and predator avoidance behaviours are lacking. Here, we investigated variation in shape and size of the brain and its six major regions of European minnows (Phoxinus phoxinus) inhabiting Lake Ånnsjön and its tributaries, using geometric morphometrics methods. We also experimentally compared stream and lake fish activity and social behaviour under different feeding and predation regimes. Contrary to our predictions of lake minnows having evolved smaller brains because of living in habitats with reduced environmental complexity compared to their conspecifics in the streams, we found that overall brain size generally did not differ between locations. Instead, brain morphology differed between minnows caught in the lake and streams, with stream minnows showing larger dorsal medulla, telencephalon and olfactory bulbs, and lake minnows presenting larger optic tecta and hypothalamus. Experimental results showed that lake minnows were more likely to engage in social behaviour than those from streams. Our results indicate that while overall allocation of energy to the brain does not change, habitat-specific differences in activity and trophic divergence might predict specialization for different senses, allocating more resources towards different brain regions. In addition, we show how various ecological factors, such as environmental complexity and social organization seem to be reflected in brain shape.
118

Variations développementales chez les poissons hybrides clonaux Chrosomus eos-neogaeus : transgressions phénotypiques en 3D

Duclos, Kevin 08 1900 (has links)
Le succès écologique des organismes dépend principalement de leur phénotype. Une composante important du phénotype est la morphologie fonctionnelle car elle influence la performance d’un organisme donné dans un milieu donné et donc reflète son écologie. Des disparités dans la morphologie fonctionnelle ou dans le développement entre espèces peuvent donc mener à des différences écologiques. Ce projet évalue le rôle des mécanismes de variation morphologique dans la production de différences écologiques entre espèces au sein des poissons hybrides du complexe Chrosomus eos-neogaeus. En utilisant la microtomodensitométrie à rayons X et la morphométrie géométrique 3D, la forme des éléments des mâchoires est décrite pour comparer la variation morphologique et les différences développementales entre les membres du complexe C. eos neogaeus. Les hybrides présentent autant de variation phénotypique que les espèces parentales et présentent des phénotypes nouveaux, dit transgressifs. Les hybrides présentent aussi des différences marquées avec les espèces parentales dans leur allométrie et dans leur intégration phénotypique. Finalement, ceux-ci semblent être plastiques et en mesure de modifier leur phénotype pour occuper plusieurs environnements. L’entièreté de ces résultats suggère que des changements dans le développement des hybrides entraînent une différenciation phénotypique et écologique avec les espèces parentales. / An organism’s success is highly dependent on its phenotype. A major component of the phenotype is functional morphology because of its role in determining performance in a given environment clues as to their ecology. Morphological disparity and developmental differences between species can thus lead to ecological differences. This project assesses the role that mechanisms capable of generating morphological variation have in producing ecological differences between species within the hybrid fishes of the Chrosomus eos-neogaeus complex. Using X-ray based computer-aided micro-tomography and 3D geometric morphometrics, the shape of bones composing the jaws was described to measure morphological variation and developmental differences in the C. eos-neogaeus complex. Chrosomus eos-neogaeus hybrids displayed as much variation as parental species and novel, deemed transgressive, phenotypes. Hybrids were also markedly different from parental species in their patterns of allometric scaling and phenotypic integration. Finally, hybrids appeared to be plastic and able to acclimate to different environments. The results of this study indicate that changes in the development of hybrids could lead to phenotypic and, in turn, ecological differences with parental species.
119

Tvarová variabilita proximální a distální části lidské kosti holenní / Shape variability of proximal and distal human tibia.

Brzobohatá, Hana January 2014 (has links)
The aim of this study was to detect and describe the trends in shape variability of proximal and distal human tibia related to sex, age, social status and time period. The variability of its shape and form was analysed first in an early medieval sample, then in two modern populations, an early 20th century sample and the contemporary Czech population. Finally, data from the whole studied time span were analysed. The initial raw data were acquired by optical scanning and computed tomography (CT) scanning of the lower limbs; the three-dimensional bone surfaces of the contemporary tibias were segmented from the clinical CT scan sequences. Geometric morphometrics and multivariate statistical methods were applied to study the variations in shape and form quantitatively. Proximal and distal tibias were evaluated independently, and the potential influence of sex, age at death and time period were investigated. In the early medieval population, we also explored the relationship between tibial morphology and presumed social status derived from the respective grave location within the settlement. Because traditional morphometric analysis revealed statistically significant sex differences in the parameters of both tibial extremities (e.g., Steyn and Işcan, 1997; Šlaus et al., 2013), we thus assumed the...
120

Apport de la reconstruction virtuelle du bassin Regourdou 1 (Dordogne, France) à la connaissance des mécaniques obstétricales néandertaliennes. / Contribution of the virtual reconstruction of the pelvis Regourdou 1 (Dordogne, France) in the knowledge of the Neandertal obstetrical mechanics.

Meyer, Valentine 04 October 2013 (has links)
La découverte d’un nouveau bassin, Regourdou 1, offre l’occasion de discuter de l’implication fonctionnelle de la morphologie pelvienne néandertalienne. Dans un premier temps, ce spécimen est décrit, ce qui permet de vérifier son appartenance aux Néandertaliens et mettre en évidence certains traits spécifiques à cette population. Bien qu’aucun ne soit autapomorphique, la combinaison de ces caractères caractérise la ceinture pelvienne néandertalienne. Le bassin Regourdou 1 est ensuite reconstruit à l’aide d’une estimation desdonnées manquantes, par thin-plate spline à partir de Kebara 2. Les dimensions du canal pelvien de Regourdou 1sont comparées à celles de deux autres spécimens néandertaliens (Tabun C1 et Kebara 2) et d’une populationmoderne (n=151). L’analyse de la morphologie des détroits obstétricaux néandertaliens (par morphométrie géométrique), et de la relation céphalo-pelvienne, met en évidence la présence de caractéristiques associées chez l’Homme anatomiquement moderne à la naissance rotationnelle. Notre travail confirme l’existence de mécaniques obstétricales néandertaliennes de type moderne. Cette interprétation permet d’enrichir notre connaissance biologique et culturelle de cette population. / The discovery of a new Neandertal pelvis, Regourdou 1, allows discussing the functional implications of Neandertal pelvic morphology. First, the specimen is described, which offers to proveits affiliation to the Neandertal population and to highlight specific Neandertal features. Even if none of these are autapomorphic, the combinaison of these traits characterize the Neandertal pelvic belt. The pelvis Regourdou 1 is reconstructed, by an estimation of missing-data, thanks to the thin-plate splines method, applied on Kebara 2. The dimensions of Regourdou 1 birth canal are compared with those of two others Neandertal individuals (Tabun C1 and Kebara 2) as well as a modern population (n=151).The analysis of the obstetrical planes morphology (by geometric morphometrics) and the cephalo-pelvic relation highlights the presence of traits associated with rotational birth in modern Human. Our work attests the existence of modern type obstetrical mechanics, in Neandertal. This interpretation allows enriching our biological and cultural knowledge of this population.

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