Okay, I love Pokemon, but one thing I’ve always wished that the series hadn’t done was use the word “evolution” to refer to something that’s, you know, not what that word normally means in other contexts. Jen McCreight has an excellent post on her blog that goes into more detail about evolution and metamorphosis in Pokemon.
What you normally think of when someone says “Pokemon evolution” is really metamorphosis. Which is kind of obvious, considering in most Pokemon games the first Pokemon that you see evolve will be a bug type whose evolution is based on metamorphosis in real insects, like a caterpillar/cocoon/butterfly. Other times, Pokemon based on animals that mature gradually will suddenly evolve instead, but then, Pokemon based on mammals come from eggs too, so it’s just a similar deviation from reality. Pokemon aren’t actually evolutionary (in the real-life biology sense) relatives of the real-life creatures they’re based on (which don’t seem to exist in the Pokemon world anyway), so that’s fine. Either way, it’s still often something like a lion cub becoming an adult lion.
On the Edge of Enlightenment 