9 resultados para 39-355

em Aquatic Commons


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This is a short excerpt of the original paper giving the key to the identification of the naupliar instars of the genus Cyclops.

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This is a short excerpt of the original paper giving the key to the identification of the naupliar instars of the genus Cyclops.

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Investigations on the control of the embryonic and post-embryonic development of arthropods have formed an intensively studied field of zoological research for a long time, Here in especially favourable cases the causal chain from the operation of external factors on the influence of physiological mechanisms, eg. of the hormone variety, is known right through to its primary influences. A comparative approach to the relevant questions was in the main only made in the case of the insects. For crustacea , investigations are available almost exclusively only for the malacostraca. This study examines the influence of the factors of temperature and photoperiod on the entire development of Cyclops vicinus. Tests were made on whether the light-darkness change serves as a regulator for a possible existing molting rhythm - a question which for the entire arthropods has been settled only very rarely. The basic material for the cultures that were examined originates from Lake Constance.

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We know very little about the role of birds in different ecosystems, despite numerous interesting works of researchers and amateur ornithologist scattered throughout the world. Less attention is paid to freshwater ecosystems because of the difficulties encountered in the experimental methods as well as a lack of interest on behalf of hydrobiologists, for the activities of birds in these ecosystems. This article summarises types and morphoecological forms of waterfowl and their place in the lake ecosystem.

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Observations of individual weight, duration of development and production of different stages of Tropodiaptomus incognitus are presented. The study is based on data gathered from Lake Chad in 1968.

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Table of Contents.

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