Part Four:  Bird Lungs

Along with bird feathers, one of the most unique features—if not the most unique—in all the animal kingdom with no evolutionary pathway is the bird lung. It cannot be explained or accounted for through the random processes of natural selection. Unlike mammals and reptiles, birds possess a one-of-a-kind continuous flow-through lung system. Molecular biologist and medical doctor, Michael Denton, describes this remarkable organ in detail:

       In all other vertebrates the air is drawn into the lungs through a system of branching tubes which finally terminate in tiny air sacs, or alveoli, so that during respiration the air is moved in and out through the same passage. In the case of birds, however, the major bronchi break down into tiny tubes which permeate the lung tissue. These so-called parabronchi eventually join up together again, forming a true circulatory system so that air flows in one direction through the lungs. . . . No lung in any other vertebrate species is known which in any way approaches the avian system. Moreover, it is identical in all essential details in birds as diverse as humming birds [sic], ostriches and hawks.

Just how such an utterly different respiratory system could have evolved gradually from the standard vertebrate design is fantastically difficult to envisage. . . . Just as the feather cannot function as an organ of flight until the hooks and barbules are coadapted to fit together perfectly [another feature with no evolutionary pathway], so the avian lung cannot function as an organ of respiration until the parabronchi system which permeates it and the air sac system which guarantees the parabronchi their air supply are both highly developed and able to function together in a perfectly integrated manner.

In addition to the feather and the avian lung there are many other unique features in the biology of the birds, in the design of the heart and cardiovascular system, in the gastrointestinal system and in the possession of a variety of other relatively minor adaptions . . . which similarly defy plausible explanation in gradualistic terms. Altogether it adds up to an enormous conceptual difficulty in envisaging how a reptile could have been gradually converted into a bird. (Evolution: A Theory in Crisis, 210-213)

There is no adequate explanation for the incredible bird lung, feather, and other avian organs, all unparalleled in the animal kingdom, other than purposefully designed and created by God. ©