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Melanism in free living vertebrates
Slavíková, Ema ; Munclinger, Pavel (advisor) ; Exnerová, Alice (referee)
Melanism is an over-development of melanin in the skin and its cover that is described in a large number of species in vertebrates. Increasing number of studies observing melanistic traits in animal species tends to reveal genetical, physiological and behavioural characteristics associated with dark pigmentation. This bachelor thesis briefly summarizes knowledge about occurrence and characteristics of melanistic animals associated with their specific pigmentation. Presented are rules and theories associated with melanism in vertebrates, e.g., melanocortin theory, thermal hypothesis and Gloger's rule.
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Ecological factors influencing variability of ultraviolet colouration of flowers
Zitko, Martin ; Kleisner, Karel (advisor) ; Neustupa, Jiří (referee)
Ultraviolet colouration of flowers varies both among and within species. The significance of these patterns and differences among them was usually associated with a visual per- ception of pollinators. In this study we examine the variation of marsh marigold's (Caltha palustris) bull's-eye pattern on a basis of 289 observed individuals from 32 distinct locati- ons. The variation of this pattern is shown to be quite large within separate locations and the pattern is predictably changing according to latitude. This trend of darker colouration towards the equator is an another example of a more widely understood Gloger's rule in the plant kingdom. The effect of ultraviolet radiation appears to be one of the most likely causes of this phenomenon. Hereafter we analyse the weakness of this explanation, the gaps in current knowledge and propose possible directions of further research. Keywords: ultraviolet, bull's-eye, marsh marigold, Caltha palustris, Gloger's rule
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Ecological factors influencing variability of ultraviolet colouration of flowers
Zitko, Martin ; Kleisner, Karel (advisor) ; Neustupa, Jiří (referee)
Ultraviolet colouration of flowers varies both among and within species. The significance of these patterns and differences among them was usually associated with a visual per- ception of pollinators. In this study we examine the variation of marsh marigold's (Caltha palustris) bull's-eye pattern on a basis of 289 observed individuals from 32 distinct locati- ons. The variation of this pattern is shown to be quite large within separate locations and the pattern is predictably changing according to latitude. This trend of darker colouration towards the equator is an another example of a more widely understood Gloger's rule in the plant kingdom. The effect of ultraviolet radiation appears to be one of the most likely causes of this phenomenon. Hereafter we analyse the weakness of this explanation, the gaps in current knowledge and propose possible directions of further research. Keywords: ultraviolet, bull's-eye, marsh marigold, Caltha palustris, Gloger's rule
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