@Shades: I think you have a misconception about the word "species" that is causing a great deal of misunderstanding. We invented the word species. To assume that a word we invented long before we knew anything about genetics informs evolutionary processes about where to stop or how to function is a little silly. In fact, philosophers of science and scientists themselves argue a great deal about what a "species" actually even is. There are many groups of individuals that seem like they should warrant the title "species" that, were we to grant them it, would require changing the definition of species in such a way that groups of individuals that we don't want to call species are now species. The same is true on the exclusionary side of the coin. In short, as of right now, any criteria we might use to describe what sorts of things count as species is either too inclusive or too exclusive.
The reason for this is that, like many other problems in philosophy, the world does not conform to our linguistic expectations. Just because we have a word "species" doesn't mean the world works in such a way. Consequently, to say that species are somehow locked in and "microevolution" (whatever that is) can't exceed the "species boundary" is looking at the world language-down instead of facts-up.
|