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Speciation mechanisms and the role of reinforcement in mammals
Horký, Jakub ; Hulva, Pavel (advisor) ; Reifová, Radka (referee)
Speciation, the process of the formation of new species, comprises a diverse range of microevolutionary mechanisms acting in unison, which lead to the gradual formation of reproductive barriers between populations. The study of speciation has significantly progressed since its origins around the midpoint of the nineteenth century, owing to progressively improving analytical methods and the data said methods obtained, allowing us to observe previously invisible patterns and form new hypotheses on their basis. From traditional to modern research, this review's goal is to describe the contemporary understanding of speciation's concepts and mechanisms, focusing on those which are most relevant to mammals. Modern understanding of spatial contexts, prezygotic and postzygotic isolating mechanisms, and character displacement, including a type of reproductive character displacement dubbed reinforcement, are discussed. Significant emphasis is placed on the topics of maladaptive and adaptive hybridization, which, together with reinforcement and development of new genomic methods, has this review identified as the current frontier of speciation research. Keywords: reproductive isolating mechanisms, microevolution, character displacement, hybridization, reinforcement, speciation
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Craniometric study of Central European populations of the white-toothed shrews Crocidura suaveolens and C. leucodon (Mammalia: Soricomorpha)
Milerová, Petra ; Vohralík, Vladimír (advisor) ; Anděra, Miloš (referee)
Interspecific and intraspecific size variability of the skull, mandibles and teeth of the lesser white- toothed shrew Crocidura suaveolens and the bicolored white-toothed shrew C. leucodon was studied on material of 350 skulls and 465 mandibles of white-toothed shrews obtained by analysis of the barn owl pellets originating from four regions in the Czech Republic and one region in the southern Slovakia. C. suaveolens was present in all regions under study, while sympatric C. leucodon occurred in three regions only. In total, 21cranial and dental measurements and 4 mandibular measurements were investigated. It was found that the most reliable measurement enabling discrimination between skulls of both species in the whole studied material is the lenght of the lower dental row. If skulls of both species were evaluated separately for each area of their sympatry it was possible to use also the distance between second molars M2 and the width of premolar P4 . Skulls of these two species can also be distinguished by bivariate graphs using the length and width of premolar P4 and the palatal length. We studied relationships between cranial measurements of both species and geoclimatic factors such as longitude, latitude, mean annual temperature and mean annual percipitation. It was found that variability of...
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Craniometric study of Central European populations of the white-toothed shrews Crocidura suaveolens and C. leucodon (Mammalia: Soricomorpha)
Milerová, Petra ; Vohralík, Vladimír (advisor) ; Anděra, Miloš (referee)
Interspecific and intraspecific size variability of the skull, mandibles and teeth of the lesser white- toothed shrew Crocidura suaveolens and the bicolored white-toothed shrew C. leucodon was studied on material of 350 skulls and 465 mandibles of white-toothed shrews obtained by analysis of the barn owl pellets originating from four regions in the Czech Republic and one region in the southern Slovakia. C. suaveolens was present in all regions under study, while sympatric C. leucodon occurred in three regions only. In total, 21cranial and dental measurements and 4 mandibular measurements were investigated. It was found that the most reliable measurement enabling discrimination between skulls of both species in the whole studied material is the lenght of the lower dental row. If skulls of both species were evaluated separately for each area of their sympatry it was possible to use also the distance between second molars M2 and the width of premolar P4 . Skulls of these two species can also be distinguished by bivariate graphs using the length and width of premolar P4 and the palatal length. We studied relationships between cranial measurements of both species and geoclimatic factors such as longitude, latitude, mean annual temperature and mean annual percipitation. It was found that variability of...
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