This sounds a bit far fetched to me, but would it be possible for larger organisms to have no mouths, but absorb nutrients through pores in the skin and the like? could it develop a way to spit on foods to digest food, then absorb it then?
Absorption through skin is not a great idea for bigger creatures. Explanation:
When an object remains the same shape but increases in size, volume increases at a faster rate than skin volume (For example, in case of a square, the formula for volume (A) is A=l^3, where l is the length of each rib, while surface area (A) is A=8(l^2). This means that if l were to increase, the volume would equal the surface area at l=8 and would surpass the surface area when l>8). This means that the bigger a creature gets, the slower the skin surface would be compared to the volume (and therefore the energy consumption) of the creature. This means that the creature will have to develop specialized organs with a high A:V ratio (such as the intestines of the lungs) for absorbing compounds. The issue with this however, is that those types of organs have a lot of small parts, which can easily be damaged (which is why they are internal organs, not external ones like the skin). So, if a large creature were to be able to absorb enough nutrients through their skin, their skin would be very vulnerable to damage. The only environment a creature like that might be able to survive in would be a place with no wind/currents (because the friction would damage their skin) or walls (because, again, they might accidentally scrape themselves against the walls and damage their skin). Maybe it would also have to be underwater, since the water might be able to lift the protrusions on the skin and stop them from just lying against the creatures’ skin
So if the creature were like the size of a puppy or smaller, and lived underwater, it would be plausible as long as the conditions you listed are there?
I doubt that something that big would have enough surface area to absorb nutrients effectively.
I found this about the total surface area of the digestive track in humans:
That says that on average the surface area is 32m2 and from here I got the surface area of the skin:
Which is around only 2m2 (16 times too little) so this means that there’s no way a creature with the nutrient requirements of a human could absorb enough through their skin even if it was as effective as in the digestive track (I doubt that the cells are sturdy enough to replace skin). I’d guess that mammals will have similar values. And plant eaters have even longer digestive tracks.
I don’t claim that this is perfectly researched but based on this I’d say it’s highly unlikely that what you describe will work after the early multicellular stage.
Ok, thanks for answering!
Something like this would only work as a “slime” like the ones you see in fantasy games. So in other words it would simply be a large mass of cells that assorb any small particles they come into contact with. This type of digestion would make it virtually impossible for the creature to gain any real intellegence. Simply put, “move” and “consume” would be about the most the creature would be able to comprehend and that may still be a fun thing to try and make work for those people who like to challenge themselves but for the majority of the player base it would seem like a waste of time to never be able to complete the game.
That said I would love to be able to play a slime in Thrive or at the very least have the chance of having them evolve in my playthrough.
How would it be able to move? I guess it could by stiffing itself into a ball-like shape and distribute its weight in a way to roll around?
I was think more along the lines of a slug, excretes a slippery substance beneath itself and does something that looks like ~~~~ with the bottom of its mass to move. The problem with the ball idea is it wouldn’t be able to assorb at much if it moved around to quickly and it also would have a hard time going uphill against gravity.