Endosymbiotic Theory

Endosymbiotic Theory, part of Symbiogenesis, is a widely accepted theory (according to second link at bottom; “This explanation of how eukaryotic cells evolved from prokaryotic cells is the currently accepted theory in science.” Wikipedia does not comment on acceptance of the theory), and so far I haven’t heard any discussion about it. It states that things like mitochondria and chloroplasts evolved from prokaryotes. Currently mitochondria and chloroplasts are static organelles, while if this was implemented, prokaryotes would have to be engulfed by a cell and somehow survive for things like mitochondria to emerge. I want to discuss it to see if we can add it. I personally would like to see it in Thrive, which is why I’m starting this thread.
I thought it would be better to put this in Theory due to it being just a proposal. If we decide to include it in Thrive someone can start a thread in Gameplay.
I’ll give a brief gameplay example anyway:
Say the player just became a eukaryote. They would have no option to add mitochondria (or chloroplasts, chemoplasts, or nitrogen fixing plastids), so they would have to survive on proteins. Eventually they decide to engulf a prokaryote, and it survives for some reason (that we can determine in this discussion). It will still perform its processes while inside the eukaryote. For instance, if it had a metabolosome, it would be similar to a mitochondria. This would be different from just adding a metabolosome because over time the proto-mitochondria would evolve, whereas the proteins would not.
I hope I’m not duplicating another discussion somewhere.
Edit (adding a note): This could also introduce interesting things with color of chloroplasts


I think this has been already discussed somewhere. It might have been the dev discord but I’m not sure.

I like this idea and would like to see some more in depth designs for this. Though I have some concerns regarding this slowing down the microbe stage too much or making it very unpredictable / frustrating to try to unlock the kind of parts you want.

Yeah it’s a nice idea. There’s a community forum thread here with some interesting points. I know it’s a popular thing with the team.

I think most of my questions about it are gameplay related.

  • how do we teach the player that you have to engulf, for example if they get into using a pilus they might not naturally discover it. Though this probably isn’t so hard.

  • how often does an engulfed prokaryote become an endosymbiote? For example if you want to play purely as a plant is the only way to get to that point to spend a lot of time as a fast engulfment hunter to unlock the organelles?

  • when a prokaryote has been absorbed how is it different from just adding those organelles yourself? E.g. if it had 2 metabolosomes then can’t you just add those? Maybe they are more efficient which is something I guess.

  • can you edit the cells you absorb? If so aren’t you really absorbing the membranes and then retooling them to actually be what you want? For example is there any restriction on me absorbing a cell with 2 mitochondria and then replacing those, one at a time, with 2 thyloakoids so now it’s basically a chloroplast?

Anyway yeah I’d be interested to hear what ideas people have. With the ai_changes branch I’ve been trying to make hunting much harder however maybe that’s not a good idea if we want to have every Eukaryote needing to engulf.

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The biggest difference would be that the endosymbiote evolves independently, but it evolves to raise the population of your species, which includes itself. This would bring more interaction with auto-evo in. However this may not be great because that does decrease the player’s control.
An alternative would be as you said, making them more efficient because they don’t have to worry about moving around and finding food, your cell does that.

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This has in fact been discussed in depth in the past, the idea we eventually came to if i recall @tjwhale or was it @hhyyrylainen ? i hope you recall this was that at some point we want it so that when you engulf prokaryotes they become an “organelle” you can add which is more efficient than proteins. Which also allows for numerous interesting organelles that are unique ti your current game.

We also had this in previous version of thrive in 0.3.4 i think, you would have to run around gathering chloroplasts/toxin vacuoles until you randomly get the option to add them. We removed this because it was tedius and we ran into issues with the old engine.

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