I think that makes sense initially, and it’s a pretty cool thing to see. Cells obviously don’t immediately get rid of excess; vestigial parts were an important aspect proving the validity of evolution. But eventually for realism’s sakes, those parts should be selected against.
I typed up something very much based on @Buckly’s post on the development forums (Environmental Tolerance Adaptations - #23 by Buckly - Gameplay - Thrive Development Forum). It runs with a concept Maxonovien proposes. I’m sure they have thought of it in someway already, but I just wanted to type it here to help map out how it can effect the game.
CONCEPT FOR COMPOUND TOXICITY
Oxygen
Problem: Oxygen is actually a dangerous compound to many organisms, as it can significantly damage cellular metabolism by creating oxygen radicals, which alter molecular shape – catastrophic for microscopic cellular components. It is generally believed that early life had a low tolerance for oxygen, resulting in the Great Oxygenation Event; a point in our Earth’s history where, when oxygen surged as a result of photosynthesis, a massive extinction event occurred. However, once oxygen was widely available and cellular respiration/metabolism adapted, the energy potential oxygen provided was immensely beneficial for life, kickstarting a more rapid pace of evolution.
What this means for Thrive: Oxygen should initially be poisonous to cells; at the same time, it should be an essential compound to be utilized on the way to enhanced metabolism later on, or in otherwards, a checkpoint. At the beginning of the game, organisms shouldn’t have a strong resilience to oxygen, which will effectively mean that most life will be initially limited to the deeper patches. Eventually however, some organisms will evolve enough buffering to oxygen to be able to make it to the higher patches. As photosynthesizing organisms pop-up (photosynthesizing cells don’t have to be entirely aerobic if they sufficiently expel oxygen produced at a rapid pace it turns out), the player’s planet will see a rapid influx of oxygen. At this point, oxygen will be very prevalent near the surface and will increase in concentration in even the deeper patches, meaning cells will be selectively pressured to adopt oxygen-buffering practices. After a sufficient amount of time passes and as oxygen levels out, due to adaptations in related organelles, a huge surge in metabolism will occur, increasing the speed of evolution and setting the path for eukaryotic and multicellular life to start popping up.
Questions to Answer
- What negative effects will oxygen have on cells? As Buckly suggests, oxygen will basically be absorbed by cells. Negative effects won’t immediately occur, but once a critical point is reached and the cell can’t get rid of oxygen fast enough, ATP production will start taking a hit; the speed at which this point happens is dependent on the amount of oxygen present. If enough oxygen is accrued, your cell will essentially run out of ATP and die.
- How do cells counteract this? Also as Buckly suggests, an organelle will be used to help enhance the rate at which oxygen is expelled from a cell. The metabolosome is the obvious candidate, but I think just being able to place one as they exist in the game currently is a cheap move and unrealistic. I suggest that metabolosomes (and other organelles) start out as very diminished versions of themselves. As you upgrade them, both the rate at which it dumps out oxygen and how beneficial oxygen is to the microcomponent’s function increases. Eventually, you should have what we now know as a metabolosome, which properly fufills aerobic respiration.
- What limits a player from just bum-rushing a metabolosome? Nothing technically. If they wanted to, they could fully evolve a metabolosome to a point at which aerobic activity is prematurely evolved. But because oxygen wouldn’t be a major factor before the Oxygenation Event, certain upgrades after a certain point make no sense rationally. A jump from 10% to 25% aerobic respiration efficiency in metabolosomes won’t make much too much of an impact if the environment has only like 2% oxygen. As such, if an experienced player wanted to just get stuff out of the way, they could get those upgrades and still benefit in some ways. But for those playing the game at their own pace and for those reacting to what each playthrough offers, it wouldn’t make sense to just bum-rush metabolosomes when other things can be done with limited MP.
Concerns: This concept means giving the player less control and giving the environment more importance. Metabolosome progression, and thus, early metabolism will initially be limited since oxygen will start low. Currently I think this is a good thing; it’s realistic, and I don’t feel like the player is reacting to a changing environment in the current game, just to other cells. But it is something to keep in mind of.
The player will depend on the presence of photosynthesizing organisms to some extent, as they are the ones who triggered the Oxygenation Event in real evolutionary history. This can be remedied by having a hard-coded increase of oxygen in the game itself.
Furthermore, this can be customized in planet generation to dictate the pace at which the game of Thrive moves forward, similar to setting Game Speed in Civilization. Increasing the speed at which the hard-coded increase kicks in can quicken game pace, while having it be more based on the presence of thylakoid bearing organisms can lengthen game pace.
I think this is a very solid concept that is minimally invasive to the game’s existing design and with many desirable impacts. I also think another concept should be made for UV-tolerance and thylakoids (I assume they’d start out as UV-absorbing pigments) to map out the evolution of photosynthesis. I’ll cook that up soon.