addition to evolution question

[Christopher Srnka <theclaw@sprintmail.com>]

I realize that the examples I cited (sauropod necks, ankylosaur &
stegosaur armor, etc.,) are more akin to microevolution than
macroevolution, which my main question addressed. The question is
phrased correctly, the examples may not be the best. More appropriate
would be, "how did fish become amphibians become reptiles become mammals
become archosaurs, etc." Although microevolution seems to defy
explanation as well, I'd be happy if anyone could "give me a clue".
-Chris Srnka