The Ecological Implications of Body Size


Book Description

It is generally recognized that larger animals eat more, live longer, have larger offspring, and so on; but it is unusual to see these commonplace observations as a basis for scientific biology. A large number of empirically based relationships describe biological rates as simple functions of body size; and other such relations predict the intrinsic rate of population growth, animal speed, animal density, territory size, prey size, physiology, and morphology. Such equations almost always exist for mammals and birds, often for other vertebrates and invertebrates, sometimes for protozoa, algae, and bacteria, and occasionally even for plants. There are too many organisms to measure all aspects of the biology of every species of population, so scientists must depend on generalizations. Body size relations represent our most extensive and powerful assemblage of generalizations, but they have never been organized for use in ecology. This book represents the largest single compilation of interspecific size relations, and instructs the reader on the use of these relationships; their comparison, combination, and criticism. Both strengths and weaknesses of our current knowledge are discussed in order to indicate the many possible directions for further research. This important volume will therefore provide a point of departure toward a new applied ecology, giving quantitative solutions to real questions. It will interest advanced students of ecology and comparative physiology as well as professional biologists.




Environmental Radiation Effects on Mammals


Book Description

Themonographisdevotedtothetheoreticalstudiesofradiationeffectsonmammals. It summarizes the results obtained by the author over the past 30 years, most of them being of high priority. In the course of these studies, a single approach to the modeling of radiation effects on mammals has been elaborated. Speci?cally, in the framework of the developed deterministic mathematical models, the effects of both acute and chronic irradiation in a wide range of doses and dose rates on vital body systems (hematopoiesis, small intestine, and humoral immunity), as well as on the development of autoimmune diseases, are investigated. The radiation effects on the mortality dynamics in homogeneous and nonhomogeneous(in radiosensitivity) mammalian populations are also studied by making use of the developed stochastic models. The most appealing feature of these mortality models consists of the fact that they account for the intrinsic properties of the exposed organism. Namely, within these models the stochastic biometrical functions are calculated proceeding from statistical characteristics and dynamics of the respective critical body system (hematopoiesis or small intestine). The performed theoretical investigations contribute to the development of the system and quantitative approaches in radiation biology and ecology. These studies elucidate the major regulatory mechanisms of the damage and recovery processes running in the vital body systems of exposed mammals and reveal the key par- eters characterizing the processes.







Mammals


Book Description

Relative newcomers within the story of evolution, mammals are hugely successful and have colonized land, water, and air. Tom Kemp discusses the great diversity of mammalian species, and looks at how their very disparate characteristics, physiologies, and behaviours are all largely driven by one uniting factor: endothermy, or warm-bloodedness.




Health Effects of Exposure to Low Levels of Ionizing Radiation


Book Description

This book reevaluates the health risks of ionizing radiation in light of data that have become available since the 1980 report on this subject was published. The data include new, much more reliable dose estimates for the A-bomb survivors, the results of an additional 14 years of follow-up of the survivors for cancer mortality, recent results of follow-up studies of persons irradiated for medical purposes, and results of relevant experiments with laboratory animals and cultured cells. It analyzes the data in terms of risk estimates for specific organs in relation to dose and time after exposure, and compares radiation effects between Japanese and Western populations.




Health Risks from Exposure to Low Levels of Ionizing Radiation


Book Description

This book is the seventh in a series of titles from the National Research Council that addresses the effects of exposure to low dose LET (Linear Energy Transfer) ionizing radiation and human health. Updating information previously presented in the 1990 publication, Health Effects of Exposure to Low Levels of Ionizing Radiation: BEIR V, this book draws upon new data in both epidemiologic and experimental research. Ionizing radiation arises from both natural and man-made sources and at very high doses can produce damaging effects in human tissue that can be evident within days after exposure. However, it is the low-dose exposures that are the focus of this book. So-called “late” effects, such as cancer, are produced many years after the initial exposure. This book is among the first of its kind to include detailed risk estimates for cancer incidence in addition to cancer mortality. BEIR VII offers a full review of the available biological, biophysical, and epidemiological literature since the last BEIR report on the subject and develops the most up-to-date and comprehensive risk estimates for cancer and other health effects from exposure to low-level ionizing radiation.




Extinction and Radiation


Book Description

This study identifies the fall of dinosaurs as the factor that allowed mammals to evolve into the dominant tetrapod form. It refutes the single-cause impact theory for dinosaur extinction and demonstrates that multiple factors--massive volcanic eruptions, loss of shallow seas, and extraterrestrial impact--likely led to their demise. While their avian relatives ultimately survived and thrived, terrestrial dinosaurs did not. Taking their place as the dominant land and sea tetrapods were mammals, whose radiation was explosive following nonavian dinosaur extinction. The author argues that because of dinosaurs, Mesozoic mammals changed relatively slowly for 145 million years compared to the prodigious Cenozoic radiation that followed. Finally out from under the shadow of the giant reptiles, Cenozoic mammals evolved into the forms we recognize today in a mere ten million years after dinosaur extinction.




Body Size in Mammalian Paleobiology


Book Description

There is a growing interest in the biological implications of body size in animals. This parameter is now being used to make inferences and predictions about not only the habits and habitat of a particular species, but also as a way to understand patterns and biases in the fossil record. This valuable collection of essays presents and evaluates techniques of body-mass estimation and reviews current and potential applications of body-size estimates in paleobiology. Coverage is particularly detailed for carnivores, primates and ungulates, but information is also presented on marsupials, rodents and proboscideans. Body Size in Mammalian Paleobiology will prove useful to researchers and graduate students in paleontology, mammalogy, ecology and evolution programmes. It is designed to be both a practical handbook for researchers making and using body-size estimates, and a sourcebook of ideas for applying body size to paleontological problems and directions for future research.




Methods in Paleoecology


Book Description

This volume focuses on the reconstruction of past ecosystems and provides a comprehensive review of current techniques and their application in exemplar studies. The 18 chapters address a wide variety of topics that span vertebrate paleobiology and paleoecology (body mass, postcranial functional morphology, evolutionary dental morphology, microwear and mesowear, ecomorphology, mammal community structure analysis), contextual paleoenvironmental studies (paleosols and sedimentology, ichnofossils, pollen, phytoliths, plant macrofossils), and special techniques (bone microstructure, biomineral isotopes, inorganic isotopes, 3-D morphometrics, and ecometric modeling). A final chapter discusses how to integrate results of these studies with taphonomic data in order to more accurately characterize an ancient ecosystem. Current investigators, advanced undergraduates, and graduate students interested in the field of paleoecology will find this book immensely useful. The length and structure of the volume also makes it suitable for teaching a college-level course on reconstructing Cenozoic ecosystems.