Star Trek: Asterisk "Concerning Preservers"

In all of Star Trek, there has always been the question of why all the aliens just look like humans with some makeup on. The real answer was, of course, a limited effects budget. But that's not good enough. There always has to be a reason behind an on-screen limitation. If an actor can't work on the series anymore, kill her off; if Klingons suddenly have ridges, create an augment virus; if everyone speaks the same language, create a universal translator. The best storytellers cover their tails and close up their plot holes, no matter how long it takes. And this was one of the earliest questions to be answered in Star Trek lore.

The problem: pretty much every alien race is either a differently colored human or represents cultures that were particular to Earth. So far in The Original Series (having finished season two) we have seen two episodes wherein the characters encounter a culture that, by all rights, shouldn't exist on a planet far, far away. "The Omega Glory" saw an American flag being flown by people who adopted Native American ways, and "Bread and Circuses" proposed the idea of Romans having 20th century technology. When we go through season three we will find Native American cultures on planet Amerind, and that's where we'll find our answers.
The overwhelming feeling of a mystery solved.
On Amerind, we find a huge obelisk that was apparently intended to protect the planet from asteroids. This obelisk also provided Kirk and the crew with information about the Preservers. They had apparently brought a collection of Native American tribes to this planet hundreds of years ago. They even terraformed it to fit their needs. They were an advanced civilization that rescued primitive cultures in danger of extinction and planted them on other planets, thus preserving them.

The actions of these Preservers, then, accounts for the Romans who were about to fall and brought with them knowledge of the Son of God. It accounts for Americans and Chinese who devolved into spears and stones after a huge biological war. It accounts for Native Americans living peaceful lives lightyears away from the homeland. In one way or another, it accounts for every alien species that looks exactly like Humans. But those aren't the only species in the galaxy, are they? Luckily there's more.
"I am not human." [You read that in his voice.]
In The Next Generation episode, "The Chase," the Enterprise-D come across a recording from a race of ancient humanoids who explain that they seeded DNA on every habitable planet in the galaxy that would direct evolution to a humanoid end. In this way, they would preserve their humanoid race which was bound to otherwise be finite. This accounts for every other humanoid species in the galaxy; Klingons, Romulans, Vulcans, Andorians, Betazoids, Cardassians, Bajorans, etc. Writer of the episode, Ronald D. Moore, stated that while he had considered it a possibility, he intentionally left it ambiguous as to whether these ancient humanoids were, indeed Preservers. But fear not, friends, for the rabbit hole goes deeper.

A decade into the third millennium, there is no longer a Star Trek TV series in production. But it has left a lasting legacy filled with people who keep on telling stories in its universe. To fill the void of a weekly episode, most Trekkies turn to Star Trek Online, the MMORPG that takes place roughly 75 years after the Star Trek: Nemesis movie. Within this game, there are quest lines that mimic what a weekly episode might be like if the player was actually involved, and in one of those quest lines are the answers we seek. In the mission, "Cold Call," the story explicitly states that the Preservers are, indeed, the ancient humanoids. The Preservers encoded genetic memory into their DNA so that, while there are only a few hundred of them left throughout the galaxy, they can remember everything their race has ever done. Including one more thing...
Hey, buddy, I think you activated it...
you should probably talk to the Preserver now...
The Progenitors were a species discussed in The Next Generation episode, "When the Bough Breaks." They set up a computer called The Custodian to care for the Aldeans, and left behind everything they would ever need. The Aldeans eventually forgot how to use the Custodian, so the Enterprise had to come along and teach them again. The mission quest line in Star Trek Online that takes the player to the Preservers also states that the Preservers were responsible for the Custodian. The Preservers are the Progenitors and the ancient humanoids. All three of these ancient races were actually just one, beautiful, powerful race that protected the humanoid form from extinction. And that would be firmly true, were it not for the fact that Star Trek Online isn't technically considered canon. (I consider it canon, but the Powers That Be don't, I guess.) So, what could be canon?

There was another spin-off series being developed by Bryan Singer under his Bad Hat Harry studios (the same studios that produced House M.D.) called Star Trek: Federation. The conceit behind this episode was that Utopia as a goal is like the fire in an engine, while Utopia in practice was stagnation and eventually death. When we join the story in 3000 A.D., we find the United Federation of Planets in a state of stagnation and decay fighting a brand new enemy with rusted old ships that barely go warp 8 without breaking down. A major part of this series was going to be the quest to find the Preservers, in much the same way that in Stargate SG-1 we were rushing to find the Ancients. If Federation were to be developed, we could look forward to a lot more information on this race, but unfortunately for them, J. J. Abrams beat them to the punch with Star Trek (2009).
Will there ever be a Star Trek: Federation? If so, probably not until the Alternate Universe storyline of the Abrams reboot has wound down. For now, it's on the back burner not being touched, as is any kind of solid answer to the Preserver mystery. But I think we can take the ideas of Star Trek Online to heart and believe that the Preservers seeded our races and protected our cultures from extinction. After all, it's a much better answer than "we didn't have the makeup budget."