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101.
Male advertisement call characters as phylogeographical indicators in European water frogs 总被引:1,自引:0,他引:1
JULIA WYCHERLEY SIMON DORAN TREVOR J. C. BEEBEE 《Biological journal of the Linnean Society. Linnean Society of London》2002,77(3):355-365
Anuran vocalizations are valuable in the determination of species identity and have the potential to discriminate intraspecific variation. We developed novel bioacoustic sampling techniques, based on Fast Fourier Transforms, to increase the precision and sensitivity of male advertisement call analysis and applied the method to European water frogs. This approach robustly separated the three types of north European water frogs (Rana ridibunda, R. lessonae and their viable, fertile hybrid R. esculenta) by their call subunit characteristics. The hybrid frog exhibited a high frequency call component absent from both the parental species. Furthermore, call analysis demonstrated significant intraspecific differences among populations of all three frog types. Call characters of R. ridibunda changed systematically as a function of longitude. This trend may reflect either clinal variation in selection pressures across Europe, or the consequences of drift following postglacial colonization from eastern refugia. High resolution vocalization analysis therefore provides a potentially useful method for investigating intraspecific differentiation and the phylogeographical origins of anuran distributions. © 2002 The Linnean Society of London. Biological Journal of the Linnean Society, 2002, 77 , 355?365. 相似文献
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TREVOR I. FURNASS 《Freshwater Biology》1979,9(1):33-43
SUMMARY. In laboratory experiments, prey selection of zooplankters by starved perch fry ( Perca fluviatilis ) from Windermere, English Lake District, is temporally variable and there is usually, in the short-term, a persistent succession from one actively selected prey species to another. Provided that the prey is visible, the patterns of prey selection are maintained irrespective of the accessibility of the prey. The fish do not optimize their energy intake per effort. The method of observing predation activity by fish shows qualitative and quantitative prey selection as time progresses in great detail. 相似文献
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Adventitious root initiation in hypocotyls of Pinus radiataD. Don consists of three distinct phases. In the pre-initiativephase, following selection of the cuttings, no histologicalchanges are observed. The initiative phase begins with swellingof a single parenchymatous cell, the meristematic locus. Distinctcytoplasmic changes within the meristematic locus are followedby cytoplasmic migration and asymmetric division in the surroundingcortical or peripheral cells. The third, or post-initiative,phase includes continued division of derivatives of the peripheralcells to form meristemoids which subsequently differentiateinto root primordia. 相似文献
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Involvement of the Embden-Meyerhof Parnas and the pentose phosphatepathways in glucose oxidation in glucose oxidation in tobaccocallus was examined. Marked changes in the activities of glucokinase,aldolase, glucose-6-phosphate dehydrogenase, and phosphogluconatedehydrogenase were observed during culture of tobacco callusunder shoot-forming and non-shoot-forming conditions. Activitiesof these enzymes were higher in shoot-forming tissue than innon-shoot-forming tissue. Furthermore, the activities of thepentose phosphate pathway enzymes showed greater differencesthan those of the Embden-Meyerhof-Parnas pathway. Confirmationof these findings was obtained by investigating the contributionsof 14C from [14C-1]- and [14C6]-glucose to CO2 released.The significance of these findings on glucose oxidation in relationto the shoot-initiation process are discussed. 相似文献