The new Rattata in Pokemon Sun and Moon is an example of ACTUAL evolution
Pokemon Sun and Moon won't arrive till November 18th, but we're getting plenty of information about the new games in the meantime. In the above video, we can see more details on the fabled 'Z moves,' which act similarly to the 'Mega Evolutions' of X and Y, as well as what happens when you actually wake up a Snorlax.
But we also get a brief glimpse of the most recently revealed Alola 'regional variant' form, Rattata -- a Dark/Normal type with a very different moveset and appearance than its G1 counterpart. The most interesting part about Rattata, however, isn't included in the above video: it turns up in the most recent Nintendo Direct, which I've queued up below.
While several of the Alolan variants, like Meowth, are the result of humans breeding Pokemon for a particular look -- what we call anthropogenic evolution -- this is a clear example of it happening in nature. This is a rare case of Pokemon actually depicting its monsters as real wildlife, in a predator/prey relationship! As an invasive species, Rattata populations on the Alola islands grew out of control, prompting the release of predatory Yungooses to thin out their numbers. But the Rattata adapted -- evolved, and not into Raticate this time -- becoming nocturnal and developing dark coats better suited for nighttime camoflage.
As our own Mike Joffe points out, Nintendo and the Pokemon Company have historically steered clear of the more grim implications of an animal ecosystem, but this is a pretty explicit example of one species preying upon another... and the other species selecting for traits that, over time, leave it better adapted to evade predators. That's a pretty nice touch, and it shows that there's a way to talk about Real Ecology Things even amidst Pokemon's sillier take on "evolution."
Pokemon Sun and Pokemon Moon are due out on Nintendo 3DS on November 18th.