نتایج جستجو برای: daphnia

تعداد نتایج: 3312  

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2008
Adam Petrusek Jaromir Seda Jiri Machácek Stepánka Ruthova Petr Smilauer

The relative homogeneity of pelagic environments has been regarded as the reason for the absence of hybrid zones for hybridizing planktonic Daphnia (Crustacea: Cladocera); occasional dominance of interspecific hybrids over parental species was explained by their temporal superiority in fluctuating environments. However, water bodies with spatially varying environmental conditions might facilita...

Journal: :Bulletin of mathematical biology 2007
Robert Mach Frank Schweitzer

Based on experimental observations in Daphnia, we introduce an agent-based model for the motion of single and swarms of animals. Each agent is described by a stochastic equation that also considers the conditions for active biological motion. An environmental potential further reflects local conditions for Daphnia, such as attraction to light sources. This model is sufficient to describe the ob...

2015
Ercan Selçuk Ünlü Donna M. Gordon Murat Telli Muhammad Barozai

Small RNA molecules are short, non-coding RNAs identified for their crucial role in post-transcriptional regulation. A well-studied example includes miRNAs (microRNAs) which have been identified in several model organisms including the freshwater flea and planktonic crustacean Daphnia. A model for epigenetic-based studies with an available genome database, the identification of miRNAs and their...

2016
Jerome J. Weis

Positive effects of competitor species richness on competitor productivity can be more pronounced at a scale that includes heterogeneity in 'bottom-up' environmental factors, such as the supply of limiting nutrients. The effect of species richness is not well understood in landscapes where variation in 'top-down' factors, such as the abundance of predators or herbivores, has a strong influence ...

Journal: :Zootaxa 2015
Alexey A Kotov

The genus Daphnia O. F. Müller, 1785 (Anomopoda, Cladocera) has become a model genus for ecological, toxicological, and evolutionary studies. At the same time, Daphnia is a well-known example of a genus with a confused taxonomy. This review aims to identify the main sources of confusion (natural and human-caused) for the current taxonomy of Daphnia. A complete check-list of all species-group na...

2012
Nicole F. Robichaud Jeanette Sassine Margaret J. Beaton Vett K. Lloyd

Daphnids are fresh water microcrustaceans, many of which follow a cyclically parthenogenetic life cycle. Daphnia species have been well studied in the context of ecology, toxicology, and evolution, but their epigenetics remain largely unexamined even though sex determination, the production of sexual females and males, and distinct adult morphological phenotypes, are determined epigenetically. ...

Journal: :Jurnal akuakultura Universitas Teuku Umar 2022

This study aims to determine the growth rate of Daphnia magna with different organic fertilizers. research is an experimental using CRD (completely randomized design) 3 treatments (p) and replications (u). The fertilizer applied daphnia culture media were: P0 = Control, P1 Cow dung, P2 Swallow Manure, P3 Chicken Manure. Parameters measured included specific rate, population density daphnia. Dat...

2017
Craig A Haskell David A Beauchamp Stephen M Bollens

Juvenile salmon (Oncorhynchus spp.) use of reservoir food webs is understudied. We examined the feeding behavior of subyearling Chinook salmon (O. tshawytscha) and its relation to growth by estimating the functional response of juvenile salmon to changes in the density of Daphnia, an important component of reservoir food webs. We then estimated salmon growth across a broad range of water temper...

Journal: :Bioscience, biotechnology, and biochemistry 2005
Frank Nunes Désirée Spiering Marc Wolf Alexandra Wendler Ralph Pirow Rüdiger J Paul

A genomic fragment containing the hemoglobin gene dmhb4 of Daphnia magna was cloned and its nucleotide sequence determined. Concerning induction under hypoxic conditions, dmhb4 was found to be expressed constitutively with similar mRNA quantities in D. magna bred in either normoxic or hypoxic medium. Southern blot analysis revealed at least six hemoglobin-like sequences in the genome of Daphnia...

Journal: :Zootaxa 2013
Ekaterina Y Popova Alexey A Kotov

Daphnia O.F. Müller (Crustacea: Cladocera: Daphniidae) is an important model in biology. It was concluded earlier that subgenus Daphnia s.str. occurs mainly in the northern hemisphere, subgenus Daphnia (Ctenodaphnia) in the southern hemisphere, which could suggest that: (1) the subgeneric differentiation is correlated with the Laurasia-Gondwanaland subdivision and (2) D. (Ctenodaphnia) is a tax...

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