From Evolution News.

Excerpt:

In a peer-reviewed paper titled “Evidence of Design in Bird Feathers and Avian Respiration,” in International Journal of Design & Nature and Ecodynamics, Leeds University professor Andy McIntosh argues that two systems vital to bird flight–feathers and the avian respiratory system–exhibit “irreducible complexity.” The paper describes these systems using the exact sort of definitions that Michael Behe uses to describe irreducible complexity:

[F]unctional systems, in order to operate as working machines, must have all the required parts in place in order to be effective. If one part is missing, then the whole system is useless. The inference of design is the most natural step when presented with evidence such as in this paper, that is evidence concerning avian feathers and respiration.

He further notes that many evolutionary authors “look for evidence that true feathers developed first in small non-flying dinosaurs before the advent of flight, possibly as a means of increasing insulation for the warm-blooded species that were emerging.” However, he finds that when it comes to fossil evidence for the evolution of feathers, “[n]one of the fossil evidence shows any evidence of such transitions.”

Regarding the avian respiratory system, McIntosh contends that a functional transition from a purported reptilian respiratory system to the avian design would lead to non-functional intermediate stages. He quotes John Ruben stating, “The earliest stages in the derivation of the avian abdominal air sac system from a diaphragm-ventilating ancestor would have necessitated selection for a diaphragmatic hernia in taxa transitional between theropods and birds. Such a debilitating condition would have immedi¬ately compromised the entire pulmonary ventilatory apparatus and seems unlikely to have been of any selective advantage.” With such unique constraints in mind, McIntosh argues that the “even if one does take the fossil evidence as the record of development, the evidence is in fact much more consistent with an ab initio design position – that the breathing mechanism of birds is in fact the product of intelligent design.”

Let’s take a step back and ask what counts as evidence for (macro) evolution for people who actually care about evidence.

Here’s what counts as evidence:

1. A smooth sequence of fossils showing the gradual emergence of different body body features across a wide spectrum of body plans. Not just horses and whales, not just micro-evolution. Major changes in body structure, which properly dated fossils, from a wide range of body plans.
2. A lab experiment that derives a new organ type or body plan from an unmodified organism, like the Lenski experiments tried to do on a smaller scale.
3. A computer simulation that shows a string of mutations that occur on one organism that would give it a new feature or organ within a reasonable amount of time (less than 4 billion years). The mutations must be probable, and the organism must have improved functionality at each stage of its development. And a calculation would have to be done to show that each beneficial mutation would spread to the rest of the population and survive in the next generation, which is a separate question.

Do we have that evidence in the case of bird evolution (feathers and lungs)? Of course not.

Do we have that evidence in the case of evolution as a whole? Of course not.

People who embrace evolution embrace it on the basis of non-rational, non-evidential factors.