“Although Planet’s native life is based, like Earth’s, on right-handed DNA, and codes for all the same amino acids, the inevitable chemical and structural differences from a billion years of evolution in an alien environment render the native plant life highly poisonous to humans. Juicy, ripe grenade fruits may look appealing, but a mouthful of organonitrates will certainly change your mind in a hurry.”
— Lady Deirdre Skye, “A Comparative Biology of Planet”
Upon constructing a Biology Lab, the player is treated to a little technical discussion of the biology of Planet. The attentive player was likely wondering by this point about just how strangely similar life on Earth and Planet are. After all, splicing alien genes into Earth plants and vice versa seem to be fairly easily accomplished, given the fact that they’re supposedly completely alien to each other.
The answer, we learn here, is that life in the SMAC world appears to have strikingly similar chemical foundations on both Earth and Chiron. Not only do they use all the same amino acids and base pairs, but they even share the same chirality. That’s striking. Enough so to make one believe that there must be deep reasons why they would be so similar.
It’s worth taking a moment to notice that Lady Deirdre is given a chance to show a sense of humor of her own in this quote. As she says, organonitrates are toxic to humans. But, as is well-known, they’re also commonly explosive. The ‘N’ in TNT stands for ‘nitro’, after all. This implies that the grenade fruit got its name for a good reason. And the image that she’s leaving her intended audience with is something right out of Looney Tunes.
Another clue along the lines of the genesis of life on Chiron are the strange monoliths of alien manufacture that are found all across the landscape of Planet. Notably, a cluster of eight are always found in a strange region of Planet referred to as “The Ruins”, the discovery of which prompts another one of those one-page short stories.
These alien monoliths have a few interesting in-game properties. For one, they serve as an excellent tile in the early game. With no terraforming required, they yield 2-2-2, which is the maximum possible yield before the resource caps are lifted. Second, they automatically upgrade a military unit that investigates it, increasing its experience level by one. Finally, sometimes after performing that latter function, they go silent and are removed from the map.
But these strange, hi-tech monuments are the only sign of civilized alien life on Planet. The player is never made aware of any other archeological finds or fossilized remains of the previous alien inhabitants. The whole question is intentionally intended to remain a mystery to the player. But whoever these aliens may have been, it is quite likely that they were at least biologically similar to the Earthlings that have recently taken their place on Chiron’s surface.