Biology and Comparative Physiology of Birds, Volume I focuses on the physiology, classification, characteristics, and geographical distribution, as well as the digestive, blood, and nervous systems, of birds. The selection first offers information on the origin of birds and adaptive radiation in birds. Discussions focus on relative resemblances of archaeopteryx to reptiles and birds, development of homoiothermy, locomotor and feeding adaptations, and adaptive radiation within families of birds. The book also examines the classification of birds and geographical distribution of living birds. The publication takes a look at the development of birds and integumentary system. Concerns include body shape, blood, urogenital, and nervous systems, muscles and limbs, endocrine organs, feathers, and development of patterns of melanin pigmentation. The book also ponders on skeleton, digestive system, and muscle structure of birds. The selection is a vital source of information for readers interested in the physiology of birds.