Download or read book POPULATION DYNAMICS OF DAPHNIA PULEX UNDER STRESS EFFECTS OF LOW PH AND FOOD MODELLING STOCHASTIC STATISTICS LIFE TABLES written by PAUL JOSEPH RAGO and published by . This book was released on 1986 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: reduced the rate of growth in length but not the maximum length attained.
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1985 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1986 with total page 824 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of PH Stress and Harvesting on the Dynamics of Laboratory Populations of Daphnia Pulex written by U.S. Fish and Wildlife Service and published by . This book was released on 1983 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1989 with total page 984 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Consequences of Predation by Chaoborus Americanus on Daphnia Pulex written by Ken Rollin Spitze and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The direct and indirect effects of predation by the aquatic dipteran larva Chaoborus americanus on the crustacean Daphnia pulex were investigated with a combination of laboratory and field assessments. All approaches indicated that Chaoborus inflict a pattern of size-specific mortality on Daphnia that can be well approximated by a Gaussian function. Maximum vulnerability is experienced by Daphnia with body size of about 1 mm. Daphnia larger that 2 mm were essentially invulnerable. Several techniques are presented that remove biases that exist in previous methods used to assess size-specific vulnerability. C. americanus emits a water soluble chemical that induces a morphological change within clones of D. pulex, most notably, the formation of a small horn on the dorsal margin of the head. Controlled laboratory experiments indicate that the horned morph experiences a 34-67% reduction in mortality, relative to the normal morph. Life table assays of many clones that compared the induced and non-induced morphs of each clone under identical conditions (except for induction factor) indicate substantial genotype x environment interaction for life history characters. Some clones showed a dramatic increase in body size, growth, and reproduction while other clones displayed a delay in reproduction, indicating a potential energetic cost to the induced morph. The significant genotype x environment interactions for many life-history characters indicate substantial genetic variance for the phenotypic plasticity. Assessments from large genetically diverse replicate laboratory populations indicate that Chaoborus predation can have significant effects on the clonal composition of Daphnia populations. Life table studies of laboratory populations in the presence and absence of Chaoborus indicate that Chaoborus predation leads to significant changes in mean population life history. Increased immature body size and delayed maturity were the most significant effects attributable directly to Chaoborus predation.
Download or read book Sterols in Daphnia Nutrition written by Dominik Martin-Creuzburg and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The efficiency of carbon transfer from primary producers to higher trophic levels is an important factor that determines the trophic structure of aquatic food webs. A decoupling of primary and secondary production at the phytoplankton--zooplankton interface can be attributed to the nutritional inadequacy of phytoplankton species. Recently, we have shown that the low carbon-transfer efficiency from cyanobacteria to the keystone genus Daphnia is caused by the lack of sterols in cyanobacteria. In the present thesis, further evidence is provided for the significance of dietary sterols for the performance of the herbivore Daphnia. A shortage in dietary sterols had serious consequences for a variety of life history traits which points to a strong impact of dietary sterols on population dynamics of the herbivorous grazer. Cholesterol, which is of major importance in arthropod physiology, is hardly represented in plant material. Instead, eukaryotic phytoplankton contains a great variety of phytosterols that differ from cholesterol in their chemical structure. Therefore, herbivorous grazers have to use the sterols found in their diet to synthesize cholesterol. In this thesis, I showed that dietary sterols differ in their adequacy to support Daphnia growth and that structural differences of dietary sterols can have pronounced effects on life history traits of Daphnia. In the field, the carbon that is fixed by primary producers, can be modified prior to ingestion by herbivorous crustaceans. I showed here that heterotrophic flagellates and ciliates as intermediary grazers can serve as a trophic link between picocyanobacteria- and Daphnia-production, thereby upgrading the nutritional value of a picocyanobacterial food source. For heterotrophic flagellates, this trophic upgrading is primarily due to the addition of sterols to the dietary carbon. In contrast, ciliates presumably lack the ability to synthesize sterols de novo. Instead, they synthesize the pentacyclic triterpenoid alcohol tetrahymanol and related compounds that provide functional equivalents for sterols as stabilizers of cell membranes. Data presented here suggest that these sterol-surrogates replace sterols as membrane reinforcers also in crustacean tissues, leading to the observed trophic upgrading of the sterol-free picocyanobacterial diet by ciliates. Despite the production of tetrahymanol and related compounds, ciliates were found to be less nutritious for daphnids than many algae. Here, I presented data showing that the ciliates' food quality for Daphnia is significantly enhanced when the ciliates were previously fed on sterol-supplemented albumin beads. Hence, the nutritional value of ciliates for Daphnia is determined by the sterol availability in the ciliates' diet. Ciliates feeding on a prokaryotic food source cannot rely on a dietary source of sterols and, therefore, will be nutritionally inadequate for daphnids, even though the production of tetrahymanol and related compounds might partly compensate for the sterol deficiency.
Download or read book Test No 211 Daphnia magna Reproduction Test written by OECD and published by OECD Publishing. This book was released on 2008-10-16 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The test method described in this Test Guideline assesses the effect of chemicals on the reproductive output of Daphnia magna Straus. To this end, young female Daphnia are exposed to the test substance added to water at a range of concentrations (at ...
Download or read book Wildlife Disease Ecology written by Kenneth Wilson and published by Cambridge University Press. This book was released on 2019-11-14 with total page 693 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduces readers to key case studies that illustrate how theory and data can be integrated to understand wildlife disease ecology.
Download or read book Ecology written by Charles J. Krebs and published by Benjamin-Cummings Publishing Company. This book was released on 2001 with total page 695 pages. Available in PDF, EPUB and Kindle. Book excerpt: This best-selling majors ecology book continues to present ecology as a series of problems for readers to critically analyze. No other text presents analytical, quantitative, and statistical ecological information in an equally accessible style. Reflecting the way ecologists actually practice, the book emphasizes the role of experiments in testing ecological ideas and discusses many contemporary and controversial problems related to distribution and abundance. Throughout the book, Krebs thoroughly explains the application of mathematical concepts in ecology while reinforcing these concepts with research references, examples, and interesting end-of-chapter review questions. Thoroughly updated with new examples and references, the book now features a new full-color design and is accompanied by an art CD-ROM for instructors. The field package also includes The Ecology Action Guide, a guide that encourages readers to be environmentally responsible citizens, and a subscription to The Ecology Place (www.ecologyplace.com), a web site and CD-ROM that enables users to become virtual field ecologists by performing experiments such as estimating the number of mice on an imaginary island or restoring prairie land in Iowa. For college instructors and students.
Download or read book Bibliography of Agriculture with Subject Index written by and published by . This book was released on 2000 with total page 1010 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms written by and published by DIANE Publishing. This book was released on 2002 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Evolution of Senescence in the Tree of Life written by Richard P. Shefferson and published by Cambridge University Press. This book was released on 2017-02-23 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: The existing theories on the evolution of senescence assume that senescence is inevitable in all organisms. However, recent studies have shown that this is not necessarily true. A better understanding of senescence and its underlying mechanisms could have far-reaching consequences for conservation and eco-evolutionary research. This book is the first to offer interdisciplinary perspectives on the evolution of senescence in many species, setting the stage for further developments. It brings together new insights from a wide range of scientific fields and cutting-edge research done on a multitude of different animals (including humans), plants and microbes, giving the reader a complete overview of recent developments and of the controversies currently surrounding the topic. Written by specialists from a variety of disciplines, this book is a valuable source of information for students and researchers interested in ageing and life history traits and populations.
Download or read book Population Level Ecological Risk Assessment written by Lawrence W. Barnthouse and published by CRC Press. This book was released on 2007-09-25 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most ecological risk assessments consider the risk to individual organisms or organism-level attributes. From a management perspective, however, risks to population-level attributes and processes are often more relevant. Despite many published calls for population risk assessment and the abundance of available scientific research and technical tool
Download or read book The Analysis of Aquatic Toxicity Data written by S. A. L. M. Kooijman and published by Vu University Press. This book was released on 1996 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Ecology written by Roger Dajoz and published by . This book was released on 1977 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: An introductory ecology textbook.
Download or read book Principles of Ecotoxicology Second Edition written by C.H. Walker and published by CRC Press. This book was released on 2003-09-02 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decade ecotoxicology has emerged as a distinct subject of interdisciplinary character. Courses in ecotoxicology reflect this and are taught by specialists in chemistry and biochemistry through to population genetics and ecology. As the first textbook to incorporate all relevant aspects of chemistry, biochemistry, toxicology, physiology, population ecology and population genetics, the first edition of this book proved to be well received across several industries. Featuring fully revised text and new illustrations, Principles of Ecotoxicology identifies the major classes of organic and inorganic pollutants, their properties, release and environmental fate, and transport in air, water and along food chains, before considering the effects that they might have upon individual organisms and ultimately whole ecosystems. This timely second edition of Principles of Ecotoxicology incorporates data collected since the first edition on subjects of current research and media interest such as organochloride pesticides, endocrine disruptors, aquatic toxicity, industrial waste and ecotoxicity testing.
