This book encapsulates over three decades of the author's work on comparative functional respiratory morphology. It provides insights into the mechanism(s) by which respiratory means and processes originated and advanced to their modern states. Pertinent cross-disciplinary details and facts have been integrated and reexamined in order to arrive at more robust answers to questions regarding the basis of the functional designs of gas exchangers. The utilization of oxygen for energy production is an ancient process, the development and progression of which were underpinned by dynamic events in the biological, physical, and chemical worlds. Many books that have broached the subject of comparative functional respiratory biology have only described the form and function of the 'end-product,' the gas exchanger; they have scarcely delved into the factors and the conditions that motivated and steered the development from primeval to modern respiratory means and processes. This book addresses and answers broad questions concerning the critical synthesis of multidisciplinary data, and clarifies previously cryptic aspects of comparative respiratory biology.

"Amongst animals, diversity of form and of environmental circumstances have given rise to a multitude of different adap tations subserving the relatively unified patterns of cellular metabolism. Nowhere else is this state of affairs better exem plified than in the realm of respiration." Jones (1972). The field of comparative respiratory biology is expanding almost exponentially. With the ever-improving analytical tools and methods of experimentation, its scope is blossoming to fascinating horizons. The innovativeness and productivity in the area continue to confound students as well as specialists. The increasing wealth of data makes it possible to broaden the information base and meaning fully synthesize, rationalize, reconcile, redefine, consolidate, and offer empirical validation of some of the earlier anecdotal views and interpretations, helping resolve the issues into adequately realistic and easily perceptible models. Occa sional reflections on the advances made, as well as on the yet unresolved prob lems, helps chart out new grounds, formulate new concepts, and stimulate inquiry. Moreover, timely assessments help minimize isolation among investiga tors, averting costly duplication of effort. This exposition focuses on the diversity of the design of the gas exchangers and gives a critical appraisal of the plausible or constrained the evolvement of respiration. The factors that have motivated cause-and-effect relationship between the phylogenetic, developmental, and en vironmental factors, conditions, and states which at various thresholds and under certain backgrounds conspired in molding the gas exchangers is argued."

This book encapsulates over three decades of the author's work on comparative functional respiratory morphology. It provides insights into the mechanism(s) by which respiratory means and processes originated and advanced to their modern states. Pertinent cross-disciplinary details and facts have been integrated and reexamined in order to arrive at more robust answers to questions regarding the basis of the functional designs of gas exchangers. The utilization of oxygen for energy production is an ancient process, the development and progression of which were underpinned by dynamic events in the biological, physical, and chemical worlds. Many books that have broached the subject of comparative functional respiratory biology have only described the form and function of the end-product, ' the gas exchanger; they have scarcely delved into the factors and the conditions that motivated and steered the development from primeval to modern respiratory means and processes. This book addresses and answers broad questions concerning the critical synthesis of multidisciplinary data, and clarifies previously cryptic aspects of comparative respiratory biology.

In biology, few organs have been as elusive as the lung-air sac system of birds. Considerable progress has recently been made to fill the gaps in the knowledge. While summarizing and building on earlier observations and ideas, this book provides cutting-edge details on the development, structure, function, and the evolutionary design of the avian respiratory system. Outlining the mechanisms and principles through which biological complexity and functional novelty have been crafted in a unique gas exchanger, this account will provoke further inquiries on the many still uncertain issues. The specific goal here was to highlight the uniqueness of the design of the avian respiratory system and the factors that obligated it.

In biology, few organs have been as elusive as the lung-air sac system of birds. Considerable progress has recently been made to fill the gaps in the knowledge. While summarizing and building on earlier observations and ideas, this book provides cutting-edge details on the development, structure, function, and the evolutionary design of the avian respiratory system. Outlining the mechanisms and principles through which biological complexity and functional novelty have been crafted in a unique gas exchanger, this account will provoke further inquiries on the many still uncertain issues. The specific goal here was to highlight the uniqueness of the design of the avian respiratory system and the factors that obligated it.

The factors which set the metabolic potentials of animals - the physicochemistry of the respiratory medium utilized, the phylogenetic level of development, the habitat occupied, and the life-style pursued -, have been the most decisive determinants of the constructions of the gas exchangers. After molding the most appropriate respiratory devices and adjusting them in accord with the individual needs for molecular oxygen, animals occupy different ecological niches and even share common environments. From the perspective of respiration, they have very few choices: there are only two fluid respiratory media and essentially two habitable spaces - water and air. They must adapt to either and in rarer cases to both.