Effects Of Temperature On Ectothermic Organisms

The study of thermoregulation in endotherms has contributed much to the emergence of the concept of control theory in biology. By the same token, the study of tempera ture adjustment in ectotherms is likely to have a far-reaching influence on ideas on the regulation of metabolism in general. The reason for this is that ectotherms, in adapting to the vagaries of a thermally unstable environment, deploy a range of subtle molecular and organismic strategies. Thus the experimenter, using temperature changes as a tool, is well equipped to analyze some of these strategies. This approach has enabled some important mechanisms of temperature-induced adaptation to be elucidated; the most striking of these are the effects on metabolism of changes in the conformation of enzymes and the transfer properties of membranes. Furthermore, there is a vague but persistent feeling among those working in this field that changes in the nervous system will ultimately prove to be the agency by which many of the molecular mechanisms of temperature adaptation are controlled. Should this indeed be the case, a new phase would soon begin in our understanding of the interactions between the systemic and the cellular levels of organization. However, it is not only questions about the causes of temperature adaptation that can provide answers of potential importance to the general biologist; of equal significance are questions as to the meaning of temperature adaptation in a particular organism.

Temperature is one facet in the mosaic of physical and biotic factors that describes the niche of an animal. Ofthe physical factors it is ecologically the most important. for it is a factor that is all-pervasive and one that. in most environments. lacks spatial or temporal constancy. Evolution has produced a wide variety of adaptive strategies and tactics to exploit or deal with this variable environmental factor. The ease with which temperature can be measured. and controlled experimentally. together with its widespread influence on the affairs of animals. has understandably led to a large. dispersed literature. In spite of this no recent book provides a comprehensive treatment of the biology of animals in relation to temperature. Our intention in writing this book was to fill that gap. We hope we have provided a modern statement with a critical synthesis of this diverse field. which will be suitable and stimulating for both advanced undergraduate and post graduate students of biology. This book is emphatically not intended as a monographical review. as thermal biology is such a diverse. developed discipline that it could not be encompassed within the confines of a book of this size.

Physiology and body temperatures of insects.

Temperature profoundly impacts both the phenotypes and distributions of organisms. These thermal effects exert strong selective pressures on behaviour, physiology and life history when environmental temperatures vary over space and time. Despite temperature's significance, progress toward a quantitative theory of thermal adaptation has lagged behind empirical descriptions of patterns and processes. In this book, the author draws on theory from the more general discipline of evolutionary ecology to establish a framework for interpreting empirical studies of thermal biology. This novel synthesis of theoretical and empirical work generates new insights about the process of thermal adaptation and points the way towards a more general theory. The threat of rapid climatic change on a global scale provides a stark reminder of the challenges that remain for thermal biologists and adds a sense of urgency to this book's mission. Thermal Adaptation will benefit anyone who seeks to understand the relationship between environmental variation and phenotypic evolution. The book focuses on quantitative evolutionary models at the individual, population and community levels, and successfully integrates this theory with modern empirical approaches. By providing a synthetic overview of evolutionary thermal biology, this accessible text will appeal to both graduate students and established researchers in the fields of comparative, ecological, and evolutionary physiology. It will also interest the broader audience of professional ecologists and evolutionary biologists who require a comprehensive review of this topic, as well as those researchers working on the applied problems of regional and global climate change.

When survival is challenged by the cold, animals react by employing both behavioral and physiological solutions. Depending on the magni tude of the cold stress and the nature of the adjustment, simple avoidance or sophisticated capacity or resistance compensations may be used. Thus, migration, shelter seeking, metabolic and insulative compen sation, torpor, and freezing avoidance and tolerance are successful tac tics used by diverse groups of animals. To understand and appreciate the benefits of these tactics, it is necessary to examine not only the well being of the whole animal but also their basic underlying mechanisms. In ad dition, it is also of fundamental importance to grasp how seasonal cold affects the survivorship and reproductive success of populations when confronted by a general reduction in primary productivity and an elevated energy cost for maintenance (e. g. in endotherms). In this regard, a synthetic overview which integrates aspects of cell biology, biochem istry, physiology, neurobiology, behavior, and population biology should be a fruitful approach in providing a holistic understanding on how animals adapt to cold. The present volume is an attempt to achieve such an overview; its objective is to provide a depth and breadth of coverage that is essential to a full appreciation of animal adaptation to cold. It is the hope of the contributing authors that this book will serve as an effective reference text for all senior undergraduate and graduate students as well as research scientists with an interest in cold physiology.

This book provides a modern, synthetic overview of interactions between insects and their environments from a physiological perspective that integrates information across a range of approaches and scales. It shows that evolved physiological responses at the individual level are translated into coherent physiological and ecological patterns at larger, even global scales. This is done by examining in detail the ways in which insects obtain resources from the environment, process these resources in various ways, and turn the results into energy which allows them to regulate their internal environment as well as cope with environmental extremes of temperature and water availability. The book demonstrates that physiological responses are not only characterized by substantial temporal variation, but also shows coherent variation across several spatial scales. At the largest, global scale, there appears to be substantial variation associated with the hemisphere in which insects are found. Such variation has profound implications for patterns of biodiversity as well as responses to climate change, and these implications are explicitly discussed. The book provides a novel integration of the understanding gained from broad-scale field studies of many species and the more narrowly focused laboratory investigations of model organisms. In so doing it reflects the growing realization that an integration of mechanistic and large-scale comparative physiology can result in unexpected insights into the diversity of insects.

This account of the current state of foraging theory is also a valuable description of the use of optimality theory in behavioral ecology in general. Organizing and introducing the main research themes in economic analyses of animal feeding behavior, the authors analyze the empirical evidence bearing on foraging models and answer criticisms of optimality modeling. They explain the rationale for applying optimality models to the strategies and mechanics of foraging and present the basic "average-rate maximizing" models and their extensions. The work discusses new directions in foraging research: incorporating incomplete information and risk-sensitive behavior in foraging models; analyzing trade-offs, such as nutrient requirements and the threat of being eaten while foraging; formulating dynamic models; and building constrained optimization models that assume that foragers can use only simple "rules of thumb." As an analysis of these and earlier research developments and as a contribution to debates about the role of theory in evolutionary biology. Foraging Theory will appeal to a wide range of readers, from students to research professionals, in behavioral ecology, population and community ecology, animal behavior, and animal psychology, and especially to those planning empirical tests of foraging models.

Concepts of Biology is designed for the single-semester introduction to biology course for non-science majors, which for many students is their only college-level science course. As such, this course represents an important opportunity for students to develop the necessary knowledge, tools, and skills to make informed decisions as they continue with their lives. Rather than being mired down with facts and vocabulary, the typical non-science major student needs information presented in a way that is easy to read and understand. Even more importantly, the content should be meaningful. Students do much better when they understand why biology is relevant to their everyday lives. For these reasons, Concepts of Biology is grounded on an evolutionary basis and includes exciting features that highlight careers in the biological sciences and everyday applications of the concepts at hand.We also strive to show the interconnectedness of topics within this extremely broad discipline. In order to meet the needs of today's instructors and students, we maintain the overall organization and coverage found in most syllabi for this course. A strength of Concepts of Biology is that instructors can customize the book, adapting it to the approach that works best in their classroom. Concepts of Biology also includes an innovative art program that incorporates critical thinking and clicker questions to help students understand--and apply--key concepts.