Constructional and Ecological Prerequisites for the Evolution of Homeothermy

Abstract

For a full understanding of the evolution of homeothermy, the phylogenetic development of the respiratory system in lung-breathing vertebrates with its two independent lines towards birds and mammals is initially discussed. Secondly, the coordinated evolution of the cardiovascular system from reptiles to birds and mammals is described, which is directly functionally interrelated to lung evolution. Thirdly, the evolution of the locomotor system with its integration with the respiratory apparatus and its funtional dependency on the high performance rates of both repsiratory and cardiovascular systems is explained. Fourthly, the evolution of energy metabolism and its coupling to the system characteristics of the respiratory and cardiovascular apparatuses is discussed. Then, homeothermy is explained as a resulting phenomenon of the evolution of the locomotor, cardiovascular and respiratory systems. Finally, as a necessary environmental condition, the co-evolution of angiosperms and their high primary production is mentioned, which was actually the prerequisite for the high basal metabolism in homeotherms. This example of an analysis of the multiple interrelationships of organ systems in organisms and between organisms and ecosystems during their evolution towards higher integration and advanced functional levels is given to demonstrate that constructional morphology presents an adequate methodology by virtue of its comparative methods to analyze the complexity of the functional structure of organisms.