[mindcruzer]

I'm not sure why you're being downvoted. Evolution is simply the changing of allele frequencies over time, which can certainly happen in the absence of mutation. Although, I don't know that I would say "plenty" of evolution can happen without mutations, but I guess that depends on what you think "plenty" is.

[revelation]

Only changing allele frequencies is proven to result in a stable state. You need mutation for evolution.

[mindcruzer]

Changing of allele frequencies can occur by creation of new alleles (ie. mutations), but it doesn't have to. The definition encompasses both possibilities.