Membranes characteristics


Thanks for the feedback,

Regarding the questions:
@Narotiza, In the real world most organisms can survive in a relatively wide range of temperature. The more adapted to extremes however, the narrower the range your membrane will be effective. A middle-range membrane would be you jack-of-all-trades, not better than a specialized membrane in a specific environment and nowhere near able to survive extremes but able to exist in a wider range of temperatures and sharper variations like in tidepools.

Regarding the slider, i agree that this is a very good system and could definitely be used to change the membrane fluidity. Keeping it in the middle would make you great at resisting temperature variations and live in a normal range of temperature but anything a bit more extreme requires you to adapt by changing fluidity.

About the mix and match of membranes and walls, in real life you cannot mix and match any and all and there are metabolic/didn’t-stick-in-evolution reasons, but from a game stand point why the hell not? After all if the player is willing to deal with the consequences of having both a specialty membrane and a wall, this can make for some interesting options. The only limit I see, and that is from a balance/simplicity standpoint, would be to allow only one wall type at a time while any membrane could be combined with it. But again, that is only my way of seeing it and i do not know how hard or easy it is to put in game.

Finally for the Silica shell, I did say it does not block light and I understand that it can be a little misleading. Actually any wall or thicker membrane would block some amount of light. This is not much however, plants do most of the photosynthesis and have cellulose walls. At this scale I am not sure if this actually matters all that much but from a gameplay standpoint it could indeed be a good factor to have walls block some amount of light for photosynthesizing organisms. This amount should be small however as most of the photosynthesizing organisms in real life actually have a cellulose wall or silica/calcium carbonate shell.

@tjwhale, For the rate of sinking, i like the way you brought it up and can tell you some organisms do have vacuoles to increase their buoyancy. Most of the organisms living in the middle or higher part of the ocean rely on currents to keep them in suspension since things do not behave all the same at this scale. Indeed many diatoms, pretty much all those you can see that are oblong oval-shaped or banana-shaped are actually bottom dwellers in shallower waters where they photosynthesize and glue themselves to sand. This glue also holds sand particles together and diatoms are good at control erosion at a micro-scale.

About rigidity, it does not control temperature per say, but rather allows a cell to continue it’s normal life in different temperatures. Like i said earlier to Narotiza, average membranes are the jack-of-all-trade of ambient temperature while more rigid will allow to keep a normal fluidity in hotter environment instead of bursting. Fluidity increases with temperature and resistance is affected by membrane composition. A very rigid membrane will be as fluid in near a black smoker as a very fluid membrane will be in arctic conditions, each being adapted to match its living conditions. However the more specialized you are the least adaptable to change you become.

I must admit that as of right now I am a bit puzzled as to how to differentiate chitin from cellulose. At this scale pretty much everything is transparent to a certain degree but, yes, chitin more-so than cellulose. There are three main differences i can think of from the top of my head but i will look into it today: Chitin is a nitrogen rich-er material than cellulose. Cellulose walled cells tend to be more organised and geometric than chitin-walled cells, plant vs fungi. And last but not least in later stages on the game, cellulose could be reinforced with lignin to allow for woody plants instead of small herbs and ferns.

Hope that helps, do not hesitate to ask further questions!
In the meantime i have an appointment with some reference books to find more information.


I remembered a relatively important thing i forgot before. Cellulose is actually glucose chains that are bound differently from reserve glucose and chitin is nitrogen-enriched glucose that is also not bound like reserve glucose. Figured this could mean additional amonia and glucose to multiply / kind of a small upkeep of both for chitin. Also, an additional glucose cost to reproduce or upkeep for cellulose-walled cells, which, in real life, must allocate carbon to reserves, reproduction and cell wall and maintain some form of balance depending on conditions.


Here’s this silly thing:

I wanted to avoid completely different wall types being direct, linear upgrades of each other, so I made a mockup of a system where, when dragging the rigidity slider, you can pay a certain (relatively large) MP cost to jump a dotted line and unlock a certain wall type. It makes them all unique and unrelated, but I’m worried it also complicates things too much?


@Narotiza I love your doodles of these cells, they look very fun:) But I think your worries are very much warranted…
My counter-proposition: We leave the slider linear. On one extreme there‘s a fluid membrane, on the other extreme there‘s a cellulose/chitin cell wall. We don‘t really know what the gameplay distinction between cellulose and chitin would be anyways, so I propose we just make them the same thing and call it „cell wall“.
As @Estredar layed out in his long post, sicilia and calcium carbonate layers aren‘t really membranes, but shells outside of the membrane. So I propose we just put them into the „external structures“ in the organelle section and make them completely seperate from the membrane rigidity slider.
Something Estredar said which also supports this proposition is that the sicila-shell-bearers have a very fluid, amoeba-like membrane underneath the shell.


Interesting ideas. I agree that having a single slider doesn’t work so well with shells. If we put shells in the external organelles section then they are binary, there is only one thickness rather than a slider.

I’m open to options on this.

One possibility is to have a 2D selector, with the rigidity on the x axis (from soft -> normal -> double -> cell wall (both chitin and cellulose together)) and then have shells on the y axis (silica at the top -> none -> calcium carbonate at the bottom). That way you can have any kind of membrane and then put any thickness of shell around it. Cell wall + thick shell would be the ultimate defensive strategy.


@tjwhale I like the direction you‘re going in. But rather than have a 2D selection we could, you know, have two sliders. That‘s basically the same as far as I understand, just not as confusing to the player.
A reservation I have with either of these options (2D selection and two sliders) is that a slider/dimension which goes from silicia shell to no shell to carbonate shell doesn‘t really have a strong intuitive logic to it. It isn‘t intuitive that no shell is in the middle of sicila shell and c-carbonate shell.
Also a slider/dimension for shells wouldn‘t be able to control where to possible holes and spikes would be located on that shell.


I want chitin cell walls, if we have a slide my proposal is you just choose the “chitin” texture, or the “cellulose” texture so you have some options.

Also, chitin allows for budding, which could be an alternative means of reproduction, so that could be the difference.


THANKS @Untrustedlife, That was the one detail i was trying to remember, budding, yeasts! Yes, chitin wall has the advantage of allowing budding. Budding could be exactly the same thing as mitosis in game with simply a different animation.


Once the rigidity slider enters “wall” territory, allowing the player to choose between different, purely cosmetic textures, based on the different wall types estredar mentioned, is a pretty simple way of doing things, however it doesn’t really show the player how different walls behave if they’re just reskins of the same general wall. It could work if we don’t want to implement different properties yet though, and it could be a nice way for players to customize their cell.

I do want to see different wall types in the game, I’m looking forward to trying to texture the silica shell especially.
(also I still think the chitin texture looks too dark)


I‘ve come up with a suggestion of how the different cell wall types could be implemented using the linear membrane rigidity slider:
Once you‘ve evolved a certain amount of rigidity (say halfway between medium rigidity and maximum rigidity) you have to choose which cell wall type you want. (cellulose, chitin, sicilia or calcium carbonate) This choice alters how your membrane characteristics will change as you further increase your rigidity. The only way to go from one cell wall type to the other after this point is to go back towards less rigidity until you have no cell wall again. After that you could evolve another type of cell wall if you want to.
If this explanation is confusing, this visualisation should help:

Excuse my writing, please.

I still think it would be even cooler if the sicilia and carbonate shells would be placed as hexes as it would allow for more variety. This is just the alternative I suggest if that turns out to be too complicated to implement.