I'm trying to understanding how seeds are used in ecj.

My first question extends from the previous post's example. Let's say we specify 
only one seed 8000, there is only one thread and we run it for 10 generations. 
What can we expect the breeder to breed? Would it breed the same chromosome 
set across all 10 generations?

I have read that when the same seeds are used, we can replicate the result. This 
helps in testing and debugging. My second question is in what condition would 
two runs of the ecj, using the same seeds, produce different