Here, the word evolution is taken in a different sense.
Really? I disagree. I don't see a fundamental difference between a bacteria with a mutation allowing it to operate without an antibiotic-targeted chemical and a bacteria with a mutation allowing it to have membrane-encased organelles.
For that matter I don't see a fundamental difference between a single-celled bacteria (with the aforementioned eukaryotic mutation) and a colony of "bacteria" where the individuals specialize in different functions, i.e. metazoan life.
The distinction is a bit tricky to grasp, but a more formalized way of putting it is that microevolution is a modification of structures that are ALREADY in place. Whereas in macroevolution, new structures appear out of seemingly nothing.
Seemingly nothing? That never happens. Every evolutionary change is a modification to previously-existing structures. There's exrtemely little biological novelty - in fact I challenege you to identify an organism or structure that is totally novel. Even life itself displays similarities to non-living chemical replicators.
That's why I say there's no difference between micro- and macro-evolution - there isn't. There's almost no biological novelty in the world of life.
This message has been edited by crashfrog, 07-11-2004 01:53 PM