Reasonable on 12 December 2010
Evolution is essentially constant but the rate of effect varies depending upon circumstance. It's wrong to think about us being one variation for a set period of time then magically changing. Each minor change in any creature happens over time and I'd argue it's very hard to state - we evolved from A to B at this point.
When you look at species on very long timeframes the whole notion of that's a rabit - or that's a homo sapiens - becomes a bit vague.
Try to be reasonable... its easier than you think...
