Like, Baker's yeast (Saccharomyces cerevisiae) and the oral thrush culprit (Candida albicans) diverged ~ 500 MYa or that Baker's yeast (Saccharomyces cerevisiae) and people (Homo sapiens) diverged ~1300 MYa or that Baker's yeast (Saccharomyces cerevisiae) and another yeast (Schizosaccharomyces pombe) (pombe is Swahili for beer :)) diverged ~900 MYa
So there's almost as much diversity between beer brewing organisms as there is between these organisms and people.
Why do I like to argue? Ostensibly its because I like to win, but in reality I am interested in the truth or at least the closest approximation to "truth" we can get. If indeed the goal is to reveal truth, then there are rules we need to follow. (Actually this is in-and-of itself a supposition that could be argued. However, I am going to assume that if there are no rules, then truth cannot rationally be identified. This is like the underlying argument of a creationist, if god can just bring everything into being using no rational or understandable rules, then evolution must do the same thing: Thus, we hear the "never seen a dog evolve into a cat" and the "the odds of randomly getting a specific 100 amino acid protein is too great" arguments. These arguments are based on creationist understanding of how god did it, which was ruleless.)
As a primer to understanding argumentation, and to allow me to expand my own education into logic and philosophy I refer you to Dr. Wilkins excellent site Evolving Thoughts and his recent post on "A Code of Conduct for Effective Rational Discussion," and the references therein.