There is a new wave in evolutionary theory known as 'intelligent' design. Natural selection, essentially unchanged since Darwin since first postulated, has simply become for many naturalists too clumsy, too implausible, and 'too dumb.' In the pokemon world, there is really no concept of natural selection either- in fact, it's rather like evolution on stereoids. But still, behind the nuts and bolts of how the capabilities of the pokemon work, there still lies, as with all animals, the mystery of how they developed. Some pokemon can spontaneously evolve in mid-life, a concept known as metamorphosis in the insect world (and limited to only a few) and not know elsewhere in life in large part.
Intelligence is a quality that can only be described in broad terms and categories. Humans tend to be biased to think of intelligence in terms of deductive reasoning, but is not the stinger on a scorpion just as intelligent? Or is not the highly complex social structures of some creatures such as bees and ants manifestly intelligent? Outwardly, the pokemon does not appear to be very intelligent. No more so than perhaps or horses or cats. And yet physically possessing extra capabilities and furthermore use their powers only in a highly discriminate way. They possess self-discipline and loyalty.
Pokemon are creations, mythical creatures to be sure but they have a lot in common with the creatures of our world as well. Unfortunately for those of us more interested in the Pokemon world and story than in the game, this world is not very well developed in terms of how pokemon species eat, live, forage, hunt, and interact. They seem to be systematic creatures on the whole, which does not make for a very interesting or dynamic Pokemon world for us sci fi fans to explore and fantasize about.
The Pokemon story is certainly rich enough to appeal to adults should it ever become seriously developed. In the meantime, the story is just fine the way it is for kids and gamers do not care about the background of pokemon nearly as much as they are interested in the powers of each one. The pokemon story though has been robust enough to produce a slew of spinoffs and characters. From animation and comic books to the Pokemon card game, there seems to be a product for all ages and interests. In fact, even older boys enjoy collecting Pokemon stuffed toys (known as plush toys or plushies), as kind of trophies, while younger kids like them because they are cute. Kids also collect a whole array of things such as Tomy pokemon figures and all kinds of rare cards, including promo cards and legendary pokemon cards. Right now anything 'pokemon black and white' is eagerly made after, providing that the Pokemon craze looks to have no end in sight.