Does microevolution logically include macroevolution?

Quote robinrohan : The whole concept is a little slippery to me. A species is defined as an isolated gene pool. But how did the life form get isolated? If we are talking about geographical isolation, then that in itself hardly seems enough to call it a separate species.
Which comes first, the isolation of the gene pool or the physical changes?--A Physical rift/barrier may not seem like much, but remember that the accumulation of mutations within each isolated population gradually result in two gene pools that can't "interact" with each other even if the physical barrier (such as a glacier) is removed, as their genes are simply no longer compatible for reproduction due to the changes.