Hello all. This is my first post so I figured I had better start with a pressing question I have had for a while. 
There might be several ways to tackle this but i'll start with two direct questions. 

1. Are species in the A-T worldview *really* eternal? 
2. Can a series of accidental changes (possibly over several generations) mount to create a substantial change? 

Also, does anyone here know of any scholars who have commented directly on this topic? 

Thanks!