Wei, I already understand the idea that sexual selection gathers multiple mutations to dispose - i.e., the rule is still "one mutation, one death" but not "one death, one mutation". I can even accept that eliminating half the population applies more than one bit of selection pressure, because the halves are not randomly assigned. But it's not a simple matter of reading MacKay and accepting everything he says - I have to reconcile with Worden's speed limit and with Kimura, and try to get a grasp on the negentropy produced rather than the number of bits in a bitstring.

Jeff, my estimate above on how slow evolution is, was based on the historical evolution time of Earth, rather than any numerical calculation.