Temperature Biology Of Animals

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.

To humans, cold has a distinctly positive quality. 'Frostbite', 'a nip in the air', 'biting cold', all express the concept of cold as an entity which attacks the body, numbing and damaging it in the process. Probably the richness of descriptive English in this area stems from the early experiences of a group of essentially tropical apes, making their living on a cold and windswept island group half way between the Equator and the Arctic. During a scientific education we soon learn that there is no such thing as cold, only an absence of heat. Cold does not invade us; heat simply deserts. Later still we come to appreciate that temperature is a reflection of kinetic energy, and that the quantity of kinetic energy in a system is determined by the speed of molecular movement. Despite this realization, it is difficult to abandon the sensible prejudices of palaeolithic Homo sapiens shivering in his huts and caves. For example; appreciating that a polar bear is probably as comfortable when swimming from ice floe to ice floe as we are when swimming in the summer Mediterranean is not easy; understanding the thermal sensa tions of a 'cold-blooded' earthworm virtually impossible. We must always be wary of an anthropocentric attitude when considering the effects of cold on other species.

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.

Organisms are continually challenged to regulate and maintain functional capacities as their thermal environment changes. Adjustment to temperature change is evident both phenotypically in individual organisms and genotypically in the evolution of species. This volume addresses thermal adaptation by bringing together many of the leading researchers in thermal biology, with backgrounds spanning the disciplines of molecular biology, cell biology, physiology, zoology, ecology and evolutionary biology. The responses of many species to temperature are discussed in depth, through the molecular, cellular, organismal, population, and ecosystem levels. This text stands as an important contribution to the study of temperature adaptation.

How do mammals manage to maintain their body temperature within the same narrow range in environments as different as polar regions and hot deserts? This advanced text describes the morphological features and physiological mechanisms by which humans and other mammals maintain their body temperature within a narrow range despite large variations in climatic conditions and internal heat production. Its 19 chapters deal with the physics of heat exchange with the environment, and the autonomic and behavioural mechanisms available to control the loss and production of heat. The neuronal basis of temperature regulation and current concepts of the central nervous interface between temperature signals generated in the body and control mechanisms are examined in detail. This book is of invaluable help for undergraduates, postgraduates, teachers, physicians and scientists.