Mayr's opinion was that there is sufficient diversity in a genome to achieve genus evolution.
Amazing. So much of what has gone before us is still recorded in our DNA, and available as raw material for design change.
I hope they are teaching this in biology classes these days, because it's really a significant aspect of the process, one which they neglected to mention in my high school classes in the 70's.
This explains why there is such an acceleration in the diversity curve over the last 4billion years. Mutation isn't the primary driver; it's reshuffling and reuse of prior genes which is the primary force now.
Back in the precambrian, when there was less raw material (Genes) to work with and atmospheric conditions were different, I wonder if Mutation was the primary force for change?