Denyse O'Leary has an interesting post at Uncommon Descent in which the diversity among dogs is explained. The variations among canines, it turns out, are not the result of an evolutionary process in which genetic information is increased, as Richard Dawkins suggested in his critique of Michael Behe's The Edge of Evolution. Rather what happens is that new varieties arise when genetic information is actually degraded.
O'Leary quotes David DeWitt:
Many of the traits for different dog breeds are examples of neoteny.
Neoteny refers to the maintaining of juvenile characteristics into adulthood. Mutations can prevent proper development and maturation. Even though particular traits might seem like they are novel, in such cases it is really a loss of information since the animal has stunted development in one trait.
This is why some breeds of dogs are so cute and look like puppies even though they are full grown (Jack Russel, Shitzu etc).
In other words the regulatory processes that shut off the juvenile characteristic and allow for maturation have been somehow disrupted, probably through some genetic mutation, so that the juvenile characteristic persists. This is not Darwinian evolution which posits an increase in genetic information. It is in fact, the opposite.
In other words, in at least one area where we have evidence of evolution, it seems to go from more complex genetic arrangements to less complex which is exactly what creationists have been claiming for decades that all evolution does.
I'll bet Dawkins wishes he hadn't brought up the subject of dog evolution.
RLC