Origin of birds

The Origin of birds is a subject that has been extremely controversial, for the past 150 years, or so. The reason why there is so much confusion and disagreement among evolutionists about the origin of birds is the lack of transitional forms linking birds to a reptilian ancestor.

Evolutionists maintain that birds have evolved from reptiles. Alfred Sherwood Romer believe that birds had evolved from a creature similar to Saltoposuchus, a pseudosuchian thecodont reptile. Nowadays, scientists who support darwinism consider the evolution of birds one of the three main fossil proofs for the theory of evolution.

However, modern birds are significantly different from reptiles in their anatomy and physiology which leads to the question of how new anatomical structures could emerge from the old ones. An example of these embarrassing differences is in the lung structure. Reptiles have a bellows-type lung, similar to all mammals including humans. The air enters a dead-end system with branches so that the air flow is reversed with each breath. However all birds have a fundamentally different kind of system. The air flows in, and then breaks out into thousands of little parallel passages, called parabronchi, for the exchange of oxygen and then continues to flow in one direction through these parabronchi till finally exits the lung.

Archaeopteryx
Some evolutionists often cite Archaeopteryx as an example of "perfect missing link" between reptiles and birds. The name Archaeopteryx means "old wing". Ironically, wings, or more specifically the feathers are precisely the most modern part of this animal. Archaeopteryx lived allegedly 153 million years ago and the bird Confuciusornis is dated to 135 million years ago. But their alleged ancestors, the feathered dinosaurs Sinosauropteryx and Caudipteryx are dated 125 million years ago. Archaeopteryx had fully formed flight feathers, classic elliptical wings of modern wild birds, and a large wishbone for attachment of muscles responsible for the downward stroke of the wings. Furthermore, like other birds, both its maxilla (upper jaw) and mandible (lower jaw) moved. In most vertebrates, including reptiles, only the mandible moves. Moreover the unique avian lung design was already present in what most evolutionists claim is the earliest bird. Archaeopteryx has reptilian features, not found in most birds. However a fossil may be an intermediate form, sharing morphological characteristics in common, without being a transitional form (a question of origin).