Paul Nelson writes:
Could Sahotra [Sarkar] provide any experimental evidence, from any vertebrate group, that developmental pathways for whole organ systems (such as the gut) varied as significantly as his selection story requires? No — the usual term for such variation is “embryonic lethal.†Faced with data that refute the neo-Darwinian account of homology, Sahotra told a Tall One
….No problem for Sahotra, however. Natural selection, he said, simply preserved the adult anatomy — keep a tube — while allowing the developmental pathways to vary. Where’s the puzzle? Evolution triumphs again.
The charitable description for that explanation is “ad hoc.†The accurate description is the steaming organic matter, suitable for fertilizer, produced by the nethermost regions of a male bovine.