Download or read book Evolution and Molecular Mechanisms of Photoreceptor Transmutation in Reptiles written by Ryan K. Schott and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural light levels vary drastically, and to deal with this variance vertebrates typically utilize a duplex retina that contains rod photoreceptors for dim-light vision and cone photoreceptors for bright-light vision. Squamate reptiles, however, are unique in the predominance of simplex retinas that contain only rods or cones. Evolutionary transitions between rods and cones, termed photoreceptor transmutations, have been proposed to explain the evolution of these simplex retinas, but little previous work has focused on the molecular evolutionary underpinnings of the observed morphological changes. The goal of this thesis is to expand knowledge of the evolution and molecular mechanisms of photoreceptor transmutation. In the first study, I provide strong support for the hypothesis that the morphologically all-cone retina of diurnal colubrid snakes evolved through transmutation of the rods to resemble the appearance, and function, of cones. In the second, I developed a new method of targeted sequence capture that enables efficient sequencing of complete coding regions across divergent taxa, which further provided data for the final two studies. In the third, I analyzed the effect that photoreceptor transmutation and snake origins had on phototransduction gene evolution. I found results consistent with a strong effect of transmutation, including positive selection on cone-specific genes that may indicate adaptation during the evolution of rod-like cones. Furthermore, the low degree of gene loss in snakes, and a lack of relaxed selection early during their evolution, support a dim-light ancestor that lacked strong fossorial adaptations. In the final study, I used whole eye transcriptome sequencing to demonstrate that geckos do not utilize only cone phototransduction machinery as previously thought, and instead appear to co-express both rod and cone genes in cone photoreceptors. I also expand upon the third study to show that geckos experienced a similar shift in selective pressures as snakes that are also associated with transmutation. As a whole, this thesis provides the first molecular evidence for photoreceptor transmutation in snakes, produces a new methodology for efficiently producing sequence data relevant for molecular evolutionary studies, revises our view of transmutation in geckos, and provides the first evidence for molecular changes associated with photoreceptor transmutation.
Download or read book Vertebrate Photoreceptors written by Takahisa Furukawa and published by Springer. This book was released on 2016-08-23 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a series of comprehensive views on various important aspects of vertebrate photoreceptors. The vertebrate retina is a tissue that provides unique experimental advantages to neuroscientists. Photoreceptor neurons are abundant in this tissue and they are readily identifiable and easily isolated. These features make them an outstanding model for studying neuronal mechanisms of signal transduction, adaptation, synaptic transmission, development, differentiation, diseases and regeneration. Thanks to recent advances in genetic analysis, it also is possible to link biochemical and physiological investigations to understand the molecular mechanisms of vertebrate photoreceptors within a functioning retina in a living animal. Photoreceptors are the most deeply studied sensory receptor cells, but readers will find that many important questions remain. We still do not know how photoreceptors, visual pigments and their signaling pathways evolved, how they were generated and how they are maintained. This book will make clear what is known and what is not known. The chapters are selected from fields of studies that have contributed to a broad understanding of the birth, development, structure, function and death of photoreceptor neurons. The underlying common word in all of the chapters that is used to describe these mechanisms is “molecule”. Only with this word can we understand how these highly specific neurons function and survive. It is challenging for even the foremost researchers to cover all aspects of the subject. Understanding photoreceptors from several different points of view that share a molecular perspective will provide readers with a useful interdisciplinary perspective.
Download or read book Adaptive Mechanisms in the Ecology of Vision written by S. Archer and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt: John Lythgoe was one of the pioneers of the 'Ecology of Vision', a subject that he ably delineated in his classic and inspirational book published some 20 years ago [1]. At heart, the original book aimed generally to identify inter-relationships between vision, animal behaviour and the environment. John Lythgoe excelled at identifying the interesting 'questions' in the ecology of an animal that fitted the 'answers' presented by an analysis of the visual system. Over the last twenty years, however, since Lythgoe's landmark publication, much progress has been made and the field has broadened considerably. In particular, our understanding of the 'adaptive mechanisms' underlying the ecology of vision has reached considerable depths, extending to the molecular dimension, partly as a result of development and application of new techniques. This complements the advances made in parallel in clinically oriented vision research [2]. The current book endeavours to review the progress made in the ecology of vision field by bringing together many of the major researchers presently active in the expanded subject area. The contents deal with theoretical and physical considerations of light and photoreception, present examples of visual system structure and function, and delve into aspects of visual behaviour and communi cation. Throughout the book, we have tried to emphasise one of the major themes to emerge within the ecology of vision: the high degree of adaptability that visual mechanisms are capable of undergoing in response to diverse, and dynamic, environments and behaviours.
Download or read book The Vertebrate Eye and Its Adaptive Radiation written by Gordon L. Walls and published by Alpha Edition. This book was released on 2020-04 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has been considered by academicians and scholars of great significance and value to literature. This forms a part of the knowledge base for future generations. So that the book is never forgotten we have represented this book in a print format as the same form as it was originally first published. Hence any marks or annotations seen are left intentionally to preserve its true nature.
Download or read book Physics in Biology and Medicine written by Paul Davidovits and published by Academic Press. This book was released on 2008 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: This third edition covers topics in physics as they apply to the life sciences, specifically medicine, physiology, nursing and other applied health fields. It includes many figures, examples and illustrative problems and appendices which provide convenient access to the most important concepts of mechanics, electricity, and optics.
Download or read book Chemical Signals in Vertebrates 4 written by David Duvall and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reviews recent developments in our understanding of che~ ical signaling in vertebrates. After sections dealing with general princi ples and chemical aspects of vertebrate pheromones, it follows a taxonomic approach, progressing from fish to. mammals. The editors asked a diverse, international group of leading investigators, working on a wide array of vertebrate taxa and specific issues, to consider their efforts from compar ative, evolutionary, and ecological viewpoints. The relative number of manuscripts in each part does not necessarily reflect current intensity of research, since the editors invited speakers who together would provide a balanced and comprehensive overview, while avoiding duplication. Still, the part on mammals is the longest. Fourth in a series dating from 1977, this volume illuminates current trends and likely future developments in the field of chemical signaling in vertebrates. Going back even farther, the first chapter, a personal account of the past quarter century by Dr. Mykytowycz recalls the most important milestones, such as symposia, or the founding of societies and journals. He also credits those investigators who stand out by their seminal studies.
Download or read book North American Watersnakes written by J. Whitfield Gibbons and published by University of Oklahoma Press. This book was released on 2004 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many people fear snakes, and watersnakes in particular have one of the worst reputations of any snake found in North America. Some species are commonly mistaken for venomous cottonmouths, and a few may eat popular game fishes. Unfortunately, few people realize the important roles many watersnakes play in natural ecosystems and, consequently, they are still persecuted in many regions today. Seeking to overcome common misperceptions, J. Whitfield Gibbons and Michael E. Dorcas have compiled North American Watersnakes, the first comprehensive study of all fourteen species of watersnakes found in the United States, Canada, Mexico, and Cuba. Individual species accounts explore all aspects of the natural history of watersnakes in North America, including their behavior, physiology, life history, ecology, and conservation. Almost 100 color photographs accompany the text, illustrating all 14 species and nearly all subspecies. Supplementing the species accounts are detailed color maps depicting each species distribution and stunning black-and-white drawings by Peri Mason. Easy-to-use keys help readers to identify specimens at hand.
Download or read book The Sourcebook for Teaching Science Grades 6 12 written by Norman Herr and published by John Wiley & Sons. This book was released on 2008-08-11 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sourcebook for Teaching Science is a unique, comprehensive resource designed to give middle and high school science teachers a wealth of information that will enhance any science curriculum. Filled with innovative tools, dynamic activities, and practical lesson plans that are grounded in theory, research, and national standards, the book offers both new and experienced science teachers powerful strategies and original ideas that will enhance the teaching of physics, chemistry, biology, and the earth and space sciences.
Download or read book Zebra Stripes written by Timothy M. Caro and published by University of Chicago Press. This book was released on 2016-12-05 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: Why do zebras have stripes? Popular explanations range from camouflage to confusion of predators, social facilitation, and even temperature regulation. It is a challenge to test these proposals on large animals living in the wild, but using a combination of careful observations, simple field experiments, comparative information, and logic, Caro concludes that black-and-white stripes are an adaptation to thwart biting fly attack.
Download or read book In the Beginning written by Walt Brown and published by . This book was released on 2008 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This revised and expanded new edition is a meticulously documented resource dealing with the age-old creation/evolution controversy. The author, who received a PhD from M.I.T., carefully explains and illustrates scientific evidence from biology, astronomy, and the physical and earth sciences that relates to origins and the flood. The hydroplate theory, developed after more than 30 years of study by Dr. Walt Brown, explains, with overwhelming scientific evidence, earth's defining geological event - a worldwide flood. This book includes an index, extensive endnotes and references, technical notes, answers to 36 frequently asked questions on related topics, and hundreds of illustrations, most in full color.
Download or read book Phenotypic Plasticity Evolution written by David W. Pfennig and published by CRC Press. This book was released on 2021-05-31 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phenotypic plasticity – the ability of an individual organism to alter its features in direct response to a change in its environment – is ubiquitous. Understanding how and why this phenomenon exists is crucial because it unites all levels of biological inquiry. This book brings together researchers who approach plasticity from diverse perspectives to explore new ideas and recent findings about the causes and consequences of plasticity. Contributors also discuss such controversial topics as how plasticity shapes ecological and evolutionary processes; whether specific plastic responses can be passed to offspring; and whether plasticity has left an important imprint on the history of life. Importantly, each chapter highlights key questions for future research. Drawing on numerous studies of plasticity in natural populations of plants and animals, this book aims to foster greater appreciation for this important, but frequently misunderstood phenomenon. Key Features Written in an accessible style with numerous illustrations, including many in color Reviews the history of the study of plasticity, including Darwin’s views Most chapters conclude with recommendations for future research
Download or read book 50 Years of DNA written by J. Clayton and published by Springer. This book was released on 2016-04-30 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crick and Watson's discovery of the structure of DNA fifty years ago marked one of the great turning points in the history of science. Biology, immunology, medicine and genetics have all been radically transformed in the succeeding half-century, and the double helix has become an icon of our times. This fascinating exploration of a scientific phenomenon provides a lucid and engaging account of the background and context for the discovery, its significance and afterlife, while a series of essays by leading scientists, historians and commentators offers uniquely individual perspectives on DNA and its impact on modern science and society.
Download or read book Evolution of Visual and Non visual Pigments written by David M. Hunt and published by Springer. This book was released on 2014-10-04 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photopigments are molecules that react to light and mediate a number of processes and behaviours in animals. Visual pigments housed within the photoreceptors of the eye, such as the rods and cones in vertebrates are the best known, however, visual pigments are increasingly being found in other tissues, including other retinal cells, the skin and the brain. Other closely related molecules from the G protein family, such as melanopsin mediate light driven processes including circadian rhythmicity and pupil constriction. This Volume examines the enormous diversity of visual pigments and traces the evolution of these G protein coupled receptors in both invertebrates and vertebrates in the context of the visual and non-visual demands dictated by a species’ ecological niche.
Download or read book The Cambridge Dictionary of Human Biology and Evolution written by Larry L. Mai and published by . This book was released on 2005-01 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Dictionary of Human Biology and Evolution (DHBE) is an invaluable research and study tool for both professionals and students covering a broad range of subjects within human biology, physical anthropology, anatomy, auxology, primatology, physiology, genetics, paleontology and zoology. Packed with 13000 descriptions of terms, specimens, sites and names, DHBE also includes information on over 1000 word roots, taxonomies and reference tables for extinct, recent and extant primates, geological and oxygen isotope chronologies, illustrations of landmarks, bones and muscles and an illustration of current hominid phylogeny, making this a must-have volume for anyone with an interest in human biology or evolution. DHBE is especially complete in its inventory of archaeological sites and the best-known hominid specimens excavated from them, but also includes up-to-date information on terms such as in silico, and those relating to the rapidly developing fields of human genomics.
Download or read book Snakes written by Harry W. Greene and published by Univ of California Press. This book was released on 1997 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: In clear, engaging prose, "Snakes" provides an up-to-date summary of every facet of the natural history of snakes--their diversity, evolution, and conservation--and, at the same time, makes a personal statement about why these animals are so compelling. 215 color photos. 3 tables.
Download or read book The Source Field Investigations written by David Wilcock and published by Penguin. This book was released on 2012-07-31 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prepare yourself for a revealing tour through the most incredible scientific mysteries of the world with your guide David Wilcock, the New York Times bestselling author of Awakening in the Dream. More than two million people have seen David Wilcock’s incredible tour of the 2012 prophecies in his Internet documentary, The 2012 Enigma. Now, he expands his vision with a cutting-edge investigation into alternative sciences with deep insights into what is coming in our immediate future. A stunning synthesis of hidden science and lost prophecies, The Source Field Investigations exposes DNA transformation, wormholes, ancient conspiracies, the Maya calendar, and a new model of galactic energy fields triggering mental, biological, and spiritual evolution. Unlike the apocalyptic viewpoints depicted in big-budget disaster films, Wilcock believes that 2012 will be a watermark for widespread acceptance of a greater reality—and here, he lays out the blueprints for such a Golden Age.
Download or read book Occult Grand Master Now in Christ written by PROF. IYKE NATHAN UZORMA and published by Xlibris Corporation. This book was released on 2013-01-14 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: For there is nothing covered, that shall not be revealed; Neither hid, that shall not be known -Jesus Christ (Luke 12:2) The foremost conversion testimony, renowned as The Jewel Of Exposition Of Hidden Powers. A book of all times on the Highest game of occult deceit. It has opened the eyes of many in different parts of the world. Prof. Stephen Pinder Ejeh Dean, Faculty of Engineering, Ahmadu Bello University Zaria, Nigeria
