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.
But of course, the process that’s called evolution in real biology comes up in Pokemon too (not necessarily completely realistically, but certainly more realistic than, say, in X-Men), and I’m fairly certain that it has been called evolution in the games too.
So evolution means metamorphosis, and evolution also still means evolution. But X and Y introduce Mega Evolution, which isn’t either one. Mega Evolution is a temporary change during battle, and doesn’t have a basis in biology at all; instead, it’s more like an anime-style super mode.
So in Pokemon, evolution, metamorphosis, and transformation (one kind of it; there are also form changes, which are not called evolution) are all called by the same word. No wonder the scientists in the Pokemon world are confused enough that they have to rely on on kids to do most of their field research for them.
Still doesn’t explain why the day-care couple is still surprised by Pokemon eggs after they’ve already found hundreds of them, though.