February 20th, 2013 Birds' Breathtaking System In a previous
issue of Think & Believe (Vol.2, No. 5), we discussed the unique
features relating to flight in birds, including positioning and
control of feathers, size and structure of bones, and efficiency
of the circulatory and digestive systems. In this article we
consider the amazing respiratory system, which, according to Dr.
Michael Denton “seem(s) to defy plausible evolutionary
explanations.” (Evolution: A Theory in Crisis, p. 210) Most
vertebrates draw air into their lungs through a series of
branching tubes which finally terminate in tiny air sacs. The
air must enter and exit through the same tubes, leaving a
certain amount of residual (“dead”) air in the lungs. Birds have
a totally different system, though. Special air sacs extend from
the lungs into all major parts of the bird’s body. They do not
function directly in gaseous exchange, but serve as “bellows” to
maintain a constant flow through tiny air tubes where the
exchange actually takes place. The