One of the common themes throughout the Star Trek franchise is origin stories. Questions about how humanoid and non-humanoid species evolved, whether there are common ancestors among human and non-human species, and how species galaxies away from each other are so similar pop up over and over again in each of the Star Trek series.
Three of the classic Star Trek shows answered these questions by introducing an ancient species that was responsible for the development of life in their sector of the universe. Though each of these ancient species had different names, an argument could be made that they all evolved from a single ancestor.
Here’s a breakdown of each of the ancient species and an explanation of their potential common origin.
The Ancient Species of the Galaxy
In Star Trek: The Original Series, the Preservers were responsible for the conservation of life throughout the galaxy. First introduced in the third season episode, “The Paradise Syndrome,” the Preservers were an extremely advanced, ancient species. They traveled through the universe looking for species that were headed for extinction. The Preservers saved these species by transporting them to a new planet where they could thrive. In the episode, this explained how a tribe of Indigenous people from the United States was found on a planet lightyears away.
Though canon doesn’t specifically state that the Preservers originated life throughout the galaxy, they’re one of the oldest known species in the galaxy, and several species would not have survived without their intervention.
In Star Trek: The Next Generation, the Ancient Humanoids, sometimes called the Progenitors, were responsible for all humanoid life in sectors of the Alpha Quadrant. In the sixth season episode “The Chase,” the crew of the Enterprise, a Klingon crew, a Cardassian crew, and a Romulan crew were all gathering pieces of a genetic puzzle. They all converged on a planet called Vilmor II, where the last piece of the puzzle was located.
When the pieces came together, they revealed a hologram of an Ancient Humanoid. This being explained that they were the common ancestor of all the gathered species. They’d spread their DNA on planets throughout the galaxies so their species could evolve in myriad ways.
In Star Trek: Deep Space Nine, the Changelings were one of the most ancient species in the Gamma Quadrant. They were a species of shapeshifters, capable of morphing into any shape or form they desired. In their natural form, they existed in a shimmering pool called The Great Link, existing in completely liquid form. Though the Changelings were an ancient Gamma Quadrant species, they weren’t one of the original species in that sector of the galaxy.
The Changelings used to be explorers. Unfortunately, as the female Changeling told Odo in the episode, “The Search Part II,” they didn’t have peaceful interactions with other species, which they referred to as “solids.” The solids didn’t trust their shapeshifting abilities and treated them poorly. So, the Changelings created the Great Link as their sanctuary and developed a hatred for solids. The Changelings also decided that the only way to protect themselves from the solids was to control them from the shadows. So, they created the Dominion to shape interstellar politics to their will, becoming the Founders.
How the Ancient Humanoids Could be the Common Ancestor
Each of these species has a unique name, a unique history, and unique physiology. However, that doesn’t mean that they didn’t originate from the same common ancestor — the Ancient Humanoid. According to Star Trek: Star Charts and the Stellar Cartography: The Starfleet Reference Library, as referenced by Memory Alpha, the Ancient Humanoids were not native to the Alpha Quadrant, though they seeded many species there. They actually evolved in the Gamma Quadrant before traveling to the Alpha Quadrant.
So, the Ancient Humanoids started off in the same sector of the galaxy as the Changelings. In the episode “Behind the Lines,” the female Changeling told Odo that their species evolved from a non-shapeshifting, humanoid species. Since the Ancient Humanoids used their DNA to create myriad humanoid species, it’s possible that their DNA was used to create the ancient, solid ancestors of the Changelings. It’s true that the Changelings evolved very differently than any of the humanoid species the Ancient Humanoids created in the Alpha Quadrant. However, this could be explained by the different conditions in the different quadrants of space.
Once the Ancient Humanoids traveled to the Alpha Quadrant, they began spreading their DNA to populate the planets there. Then they could have moved on to spread their DNA in other quadrants of the galaxy.
As the literal parents of the galaxy, it makes sense that the Ancient Humanoids would want to keep tabs on their creations. So, at some point, their descendants likely returned to the Alpha Quadrant to see how their progeny had evolved. When their descendants arrived and found that some of the species their ancestors had created were on the verge of extinction, the descendants decided to save the species by transplanting them to different planets, meaning that the descendants of the Ancient Humanoids could be the Preservers. The species being saved by the Preservers wouldn’t have any knowledge of the Ancient Humanoids that created them because eons had passed. So, they dubbed the Ancient Humanoids the Preservers, even though it was the same species.
The Ancient Humanoids didn’t decide to reveal themselves as the common ancestor of the myriad species they created until they were dying out. So, it follows that none of the species that evolved from them knew that until it was discovered in the TNG episode “The Chase.”
Another hint to a possible connection between the species is the fact that both the Preservers and the Changelings both used obelisks to mark where they had been.
There’s also some real-world evidence to support the theory. According to the Star Trek: The Next Generation Companion, longtime Star Trek writer Ronald D. Moore intended the Preservers and the Ancient Humanoids to be the same species. He ultimately decided to leave this detail out of the final script for “The Chase.”
So, did the Preservers and the Changelings both have a common ancestor in the Ancient Humanoids? There’s nothing in canon that absolutely states this. However, there seem to be enough threads to tie the theory together.