Level Of Morphological Integration Research Articles

Влияние антропогенной нагрузки на адаптациию <i>Betula pendula</i> Roth.

В качестве объекта исследования выбран широко распространенный вид берез Betula pendula Roth. Изучены механизмы приспособления листьев в условиях антропогенной нагрузки B. pendula лесополосы вдоль автодороги Р-240 «Уфа – Оренбург» на морфологическом уровне по двум показателям — флуктуирующая асимметрия и морфологическая интеграция структуры листа. Для оценки произведена выборка 250 листьев с 25 деревьев генеративного состояния в лесополосе, расположенной вдоль автодороги Р-240 «Уфа – Оренбург» с высоким уровнем антропогенной нагрузки. Определены 40 метрических признаков для оценки уровня морфологической интеграции, среди которых 19 парных признаков для оценки флуктуирующей асимметрии. Также с помощью метода геометрической морфометрии построен усредненный образ листьев B. pendula. При расчете балльных оценок качества среды по показателям флуктуирующей асимметрии по общепринятой методике выявлено, что все деревья формировались в условиях критического (V класс) состояния среды. Тип онтогенетической стратегии — защитно-стрессовый. С усилением антропогенной нагрузки уровень морфологической интеграции возрастает, что определяет защитную часть онтогенетической стратегии, а в последующем происходит снижение показателей морфологической интеграции — проявление стрессовой компоненты. Проведение однофакторного дисперсионного анализа показало значимое влияние фактора (антропогенная нагрузка) между группами внутри генеральной совокупности. Выявлены статистически значимые различия перехода между группами деревьев по уровню морфологической интеграции. Наиболее значимые различия характерны при переходе между группами 1 и 4, 2 и 3, 2 и 4, а также 4 и 5.

Morphological Integration of the Mandible in Yellow-necked Field mice: The Effects of B Chromosomes

As a complex skeletal organ consisting of 2 functional and developmental units (ascending ramus and alveolar region), the mandible represents a well-established model in morphological integration studies. The concept of morphological integration assumes that developmentally or functionally related traits are more correlated than others and hence evolve together. We compared the level and pattern of mandibular morphological integration between groups of adult yellow-necked field mice (Apodemus flavicollis), with and without B chromosomes (Bs) in a population from Mt. Avala, Serbia. Bs are dispensable supernumerary chromosomes characterized by irregular and non-Mendelian modes of inheritance. The level of morphological integration was higher in animals with Bs. One of the 2 regions of the mandible tested (alveolar region) was significantly more affected by the presence of Bs than the other, with an increase in intensity of integration of 41.61% versus 15.86%. The hypothesis of morphological integration, which postulates disunion of the mandible into 2 distinct functional and developmental modules, was confirmed in animals with Bs. Bs probably have a function because they affect mandible phenotype (although the mechanism is unknown), increase variability within populations, and could lead to selective advantage.

Morphological integration of cranium and postcranial skeleton during ontogeny of facultative paedomorphic European newts (Triturus vulgaris and T. alpestris)

AbstractThe patterns of ontogenetic and interspecific variation of morphological integration (the relationships and correlation patterns of functionally and developmentally related morphological traits) in facultative paedomorphic species of two European newts (Triturus vulgaris and T. alpestris) were examined. The degree of morphological integration differed among ontogenetic stages. Variation in the level of morphological integration of cranium and postcranial skeleton during ontogeny of paedomorphic newts had the same pattern in both analysed species. The lowest level of cranium morphological integration characterises the larvae and the juveniles. Individuals that follow alternative life-history path (paedomorphs) remain at a relatively low level of morphological integration, while integration highly increased in metamorphosed adult individuals. Limb skeleton also showed a lower level of integration in paedomorphs in comparison with metamorphosed individuals. The hypothesis of morphological integration was confirmed for all stages of T. vulgaris, while the same hypothesis was confirmed only for larval and paedomorphic stages of T. alpestris. In T. vulgaris, metamorphosis changes the pattern of correlation among the cranial traits, while in T. alpestris, the patterns of phenotypic correlation among the cranial traits remain substantially similar for all analysed ontogenetic stages.

A comparison of phenotypic variation and covariation patterns and the role of phylogeny, ecology, and ontogeny during cranial evolution of new world monkeys.

Similarity of genetic and phenotypic variation patterns among populations is important for making quantitative inferences about past evolutionary forces acting to differentiate populations and for evaluating the evolution of relationships among traits in response to new functional and developmental relationships. Here, phenotypic co variance and correlation structure is compared among Platyrrhine Neotropical primates. Comparisons range from among species within a genus to the superfamily level. Matrix correlation followed by Mantel's test and vector correlation among responses to random natural selection vectors (random skewers) were used to compare correlation and variance/covariance matrices of 39 skull traits. Sampling errors involved in matrix estimates were taken into account in comparisons using matrix repeatability to set upper limits for each pairwise comparison. Results indicate that covariance structure is not strictly constant but that the amount of variance pattern divergence observed among taxa is generally low and not associated with taxonomic distance. Specific instances of divergence are identified. There is no correlation between the amount of divergence in covariance patterns among the 16 genera and their phylogenetic distance derived from a conjoint analysis of four already published nuclear gene datasets. In contrast, there is a significant correlation between phylogenetic distance and morphological distance (Mahalanobis distance among genus centroids). This result indicates that while the phenotypic means were evolving during the last 30 millions years of New World monkey evolution, phenotypic covariance structures of Neotropical primate skulls have remained relatively consistent. Neotropical primates can be divided into four major groups based on their feeding habits (fruit-leaves, seed-fruits, insect-fruits, and gum-insect-fruits). Differences in phenotypic covariance structure are correlated with differences in feeding habits, indicating that to some extent changes in interrelationships among skull traits are associated with changes in feeding habits. Finally, common patterns and levels of morphological integration are found among Platyrrhine primates, suggesting that functional/developmental integration could be one major factor keeping covariance structure relatively stable during evolutionary diversification of South American monkeys.

A COMPARISON OF PHENOTYPIC VARIATION AND COVARIATION PATTERNS AND THE ROLE OF PHYLOGENY, ECOLOGY, AND ONTOGENY DURING CRANIAL EVOLUTION OF NEW WORLD MONKEYS

Similarity of genetic and phenotypic variation patterns among populations is important for making quantitative inferences about past evolutionary forces acting to differentiate populations and for evaluating the evolution of relationships among traits in response to new functional and developmental relationships. Here, phenotypic covariance and correlation structure is compared among Platyrrhine Neotropical primates. Comparisons range from among species within a genus to the superfamily level. Matrix correlation followed by Mantel's test and vector correlation among responses to random natural selection vectors (random skewers) were used to compare correlation and variance/covariance matrices of 39 skull traits. Sampling errors involved in matrix estimates were taken into account in comparisons using matrix repeatability to set upper limits for each pairwise comparison.Results indicate that covariance structure is not strictly constant but that the amount of variance pattern divergence observed among taxa is generally low and not associated with taxonomic distance. Specific instances of divergence are identified. There is no correlation between the amount of divergence in covariance patterns among the 16 genera and their phylogenetic distance derived from a conjoint analysis of four already published nuclear gene datasets. In contrast, there is a significant correlation between phylogenetic distance and morphological distance (Mahalanobis distance among genus centroids). This result indicates that while the phenotypic means were evolving during the last 30 millions years of New World monkey evolution, phenotypic covariance structures of Neotropical primate skulls have remained relatively consistent.Neotropical primates can be divided into four major groups based on their feeding habits (fruit-leaves, seed-fruits, insect-fruits, and gum-insect-fruits). Differences in phenotypic covariance structure are correlated with differences in feeding habits, indicating that to some extent changes in interrelationships among skull traits are associated with changes in feeding habits. Finally, common patterns and levels of morphological integration are found among Platyrrhine primates, suggesting that functional/developmental integration could be one major factor keeping covariance structure relatively stable during evolutionary diversification of South American monkeys.Corresponding Editor: T. Mousseau

Morphological integration and covariance during astogeny of an Ordovician trepostome bryozoan from communities of different diversities

Correlations exist between diversity and colonial growth pattern and variability in Paleozoic stenolaemate bryozoans. Habitats occupied by diverse communities contained colonies whose growth trajectories were different and were more highly constrained than those of low-diversity habitats. Because previous studies have not examined variability during colony growth, it was unclear whether observed variabilities were constant during growth (astogeny) or whether variability changed with age. Astogenetic trajectories and growth variability are here reexamined in populations of colonies ofHeterotrypa ulrichifrom the same high-diversity and low-diversity communities examined by Pachut (1989).Growth trajectories of populations differ in both intermonticular and monticular regions of colonies for fundamental stereological characters. Total zooidal surface areas generally decrease during astogeny whereas zooidal densities increase. Surface areas per zooid also decrease with increasing age, but are consistently larger in monticular zooecia and in populations from low-diversity communities irrespective of the colony region sampled. These patterns of declining values are caused by increasing wall thicknesses, larger and more abundant mesozooecia and acanthostyles, and the development of maculae during colony growth. Larger values in low-diversity settings may have provided reproductive and feeding benefits necessary for survival.Covariances reflect levels of morphological integration and are larger in populations from high-diversity communities in both intermonticular and monticular regions. Values differ more during early stages of growth (1–3) than later in astogeny (stages 4–5), and are consistently higher in intermonitulcar than in monticular zooecia. Lower levels of integration in monticules may be caused by spatial adjustments as the number of monticules increases across the expanding colony surface during growth. In general, stabilizing selection may have been weaker and less effective in establishing character covariance patterns in populations from low-diversity communities, perhaps because of greater environmental stress. These findings suggest that evaluations of astogenetic patterns and age-related changes in levels of morphological integration within a paleoenvironmental context are important in measuring species richness, in determining the direction of character evolution, and in assessing tempo and mode of evolutionary changes.

Ornamental polymorphism and morphological integration in Brizalina mandoroveensis (Miocene, Cameroun)

The Miocene foraminiferal species Brizalina mandoroveensis (Graham, deKlasz, Rérat) from the Early to Middle Miocene of the Gulf of Guinea, West Africa, displays polymorphism in its pattern of ribbing, such that the normal form is ornamented with longitudinal riblets and the subordinate morph with a ladderlike pattern of struts joined in parallel to riblets. Multivariate statistical analyses based on size variables disclose subtle differences in the variability of the tests, which may be correlated with the frequencies of the two morphs in a particular sample. The relationship between sets constituted by morphological size variables, on the one hand, weighed against measures of shape, on the other, shows a significant relaxation in the level of morphological integration between sets over time.