I'm expanding on a couple of different posts I made at the Skeptic's Annotated Bible Discussion Board, one of my favorite hang-outs. Basically, you see a lot of probability discussions in IDC literature. This is one more reason why they are nonsense. They generally looked at random mutation (that is, the replacement of one "letter" in the DNA with another letter) and natural selection.
There are at least 18 different mechanisms involved in evolution:
Mechanisms that increase diversity in a population
Random replacement mutation in DNA
Frame shift mutation
Gene flow from other species
Environmentally generated changes to DNA decoding
Protein changes (prions, etc.)
Mechanisms that alter allele proportions in a population
Sexually antagonistic selection
Random genetic drift
Mechanisms that operate at a level above populations
Mass extinction events
Parasitic/symbiotic relationships (note this is different from the symbiosis that occurs at the genetic/cellular level).
To do a probability calculation, you need to account not only for the probabilities of each of these mechanisms, but also for the independence of every possible subset of these mechanisms. that would be 524,288 (2^19)
Just one more way IDC falls short of even it's own goals.