[aNYCguy]

My staunch "evolution explains everything" prof for my undergrad evolutionary biology course said there was a distinction.

Please explain to me, in your own words, the distinction between "micro" and macro" evolution. Then please explain to me what force or forces prevents enough microevolutionary changes from summing into macro change.

[Exigence]

Then please explain to me what force or forces prevents enough microevolutionary changes from summing into macro change.

I'd be delighted. Please give me the change you'd like me to discuss... one with hard evidence behind it. If there is no prevention, as you allude, you should be able to supply dozens of examples with a clear record of progression from species to species.