The structure, origin, and spread of the family Percidae are reviewed briefly, and its characteristics compared with those of other families of freshwater fishes. It is suggested that the percids, essentially riverine, have been restricted in their success in North America by the presence of the Centrachidae. Percids are defined as temperate mesothermal fish, and this physiological characteristic together with osmoregulatory capacity and swimming performance is shown to limit the ranges of the perches. The degree of development of the tapetum lucidum in Stizostedion spp. and of the lateral line in all percids is related to differences in pattern of development, feeding behavior, and habitat. Reproductive, feeding and migratory behaviour are also reviewed. Key words: Percidae, structure, origin, biology, morphology, systematics, migration
The early development of the lateral-line systems in Eurasian perch (Perca fluviatilis) and the ruff (Gymnocephalus cernua) is described and related to development of behavior patterns characteristic of the two species. Perch are active pelagic predators for whom vision is of greatest importance in obtaining food, whereas ruff are benthophages of slow-flowing waters and typically obtain their food as solitary ambush predators for whom the highly sensitive lateral-line system is extremely important. The less developed system of the perch seems to match its greater ecological plasticity. Key words: Percidae, Perca, Gymnocephalus, lateral line, development, behavior, sensory organs
SynopsisA brief overview of the origin and application of the ecomorphological concept in Russia is presented : It all started with S.G . Kryzhanovsky at the Severtsov's Laboratory of Comparative Morphology' who studied the respiratory function of embryonic blood circulation (1933) . Later Kryzhanovsky and V V Vasnetsov formulated a theory of qualitative 'etaps' (ontogenetic intervals) in the development of fishes, a theory which their students and collaborators subsequently applied to many different taxa . At the same time Kryzhanovsky proposed a second theory according to which fishes can be assigned to ecological groups based on features of their spawning habitats and on specific characteristics of their early and late ontogeny. In the last forty years many followers expanded and tested these theories as is demonstrated by the partial bibliography compiled at the end of this paper .
The results of the research and comparative assessment of the cumulative properties of nanodisperse and microdisperse nickel oxide in the experiment are presented. It is found that after the intragastric gavage of the nanodisperse nickel oxide for 16 days (total dose administered was 16250 mg / kg) it possesses a functional accumulation, as it is evidenced by the morphological changes in the tissues of the gastrointestinal tract, liver, spleen, and material accumulation indicator which is an increase of its concentration in the brain, liver and kidneys relative to controls (4.7, 8.1 and 23.6 times, respectively). Microdisperse analague also has a functional and material accumulation, but the degree of manifestation is different from the accumulation of nanodisperse nickel oxide. The accumulation of the substance occurs only in brain and liver, and in lower concentrations as compared to the nanodisperse nickel oxide (1.7 and 3.6 times). The morphological changes of tissues of the gastrointestinal tract and the spleen are less pronounced, any change in liver tissue is not established.
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