They would use up compounds. We could implement a cooldown as well if we find they are overpowered.
I’ll explain that at the bottom of this post.
I feel like lava spots would be too unrealistic, but I think something like patches of dangerously hot water would be a good alternative (near the vents).
On the point of mitochondria and aerobic (oxygen based) respiration, I fully agree. One of the major consequences of an Oxygenation event is the ability for organisms to aerobically respire which gives much larger amounts of energy.
There have been quite a few questions and confusions floating around slack and the dev forums on the many concept changes we’ve had recently. I think this is understandable because we’ve redesigned many aspects of the game and reached a state that I think is a LOT more fun AND realistic than what we had before. However, it’s vital we all get to the same page for moving forward.
Microbe Bioenergetics
First a quick explanation of the confusion between producing ATP, photosynthesis, and chemosynthesis.
The Basic Principle of Life
In the chemical world, multi-atomic molecules are held together by bonds between its atoms. These bonds have energy stored in them, and breaking these bonds will release that energy. Some molecules have bonds that have a lot of energy stored in them, and some very little. All life is based on the principle of finding molecules with energy rich bonds in nature, breaking those bonds (aka digestion), and harvesting the energy from those bonds. Many molecules are very hard to break apart and/or yield very little energy, which is why most life has evolved to harvest energy from the same set of chemicals.
ATP
In cells, the way they capture that released energy is through ATP. When a cell needs energy, it will break an energy rich bond from one of its food molecules and then “capture” that energy with ATP to be used immediately on moving or maintaining its membrane or what have you.
Energy Rich Molecules
Glucose is the most commonly used energy rich molecule in nature. In the absence of oxygen, cells will break apart 1 molecule of glucose to produce 2 ATP, as well as 2 ethanol and 6 carbon dioxide as waste. In the presence of oxygen, cells will use it to help break apart 1 molecule of glucose to produce 36 ATP, use up the 6 molecules of oxygen, and produce 6 molecules of water and 6 molecules of carbon dioxide as waste.
However, glucose is not the only energy rich molecule in nature. Some cells take Iron (III) and separate one of its electrons, forming Iron (II). This process releases a certain amount of energy which is then “captured” by ATP, just like with glucose. In this case, I believe 2 ATP is produced by the iron. Note that this doesn’t make the cell a chemosynthesizer, it simply uses iron instead of glucose for energy. I will explain chemosynthesizers later.
Other energy rich chemicals that can be used include manganese (IV), carbon dioxide, and sulfur. This process of breaking down energy rich molecules to harvest their energy in the form of ATP is called respiration. For example, aerobic (oxygen based) respiration, where oxygen is used to help break down glucose. Anaerobic respiration is breaking down energy rich compounds without the use/aid of oxygen, such as the iron example above.
Biosynthesis
Biosynthesis refers to the ability of a cell to create its own energy rich molecules, instead of having to search for them in the environment. Photosynthesis is a type of biosynthesis where a cell uses light (Photo-) to produce (-synthesis) glucose from chemicals, namely carbon dioxide and water, and producing oxygen as waste. It then breaks apart this glucose just like mentioned above to harvest the energy.
Wait a second Nick, doesn’t creating the glucose cost energy? Yes, yes it does, but not as much as harvesting the energy from it afterwards, so overall you actually make an energy profit. However, the energy profit is pretty slim, which is why most organisms that use photosynthesis to produce their own glucose don’t move (moving is very energy expensive).
Chemosynthesis
Chemosynthesis is the same principle. However, instead of using light AND chemicals to produce energy rich chemicals, it just uses chemicals. Chemosynthesis is actually an umbrella term for many different processes. For example, cells that use hydrogen sulfide chemosynthesis spend some energy to produce glucose from hydrogen sulfide and carbon dioxide. Water and sulfur are produced as waste. The cell then breaks apart the glucose for energy, making an energy profit. Remember, a chemosynthesizer might not necessarily produce glucose, it might produce some other energy rich molecule which will then be harvested for energy profit.
Microbe Biomes
Next a quick spiel on the environment and environmental variables.
Oxygen, Carbon Dioxide, and Other Gasses
The plan is to remove carbon dioxide and oxygen from the game as tracked compounds. We could potentially relegate other gaseous compounds to this position as well. This would mean these compounds are not shown as clouds, nor do they take up storage in the cell. They are still relevant in the processes that use them though. How can we model this? These are the options I can think of:
- On/off. Ex. Aerobic respiration will run if oxygen is present, and stop if its not.
- Above a threshold. Ex. Aerobic respiration will run only if oxygen is above a certain amount.
- Scaling. Ex. Aerobic respiration’s reaction speed will scale with the presence of oxygen. More makes it run faster, less makes it run slower.
We should decide on one of these approaches to take. I’m leaning towards the third one.
Biome Differences
Some biomes may have more oxygen and some more carbon dioxide. What’s the point of this?
- It makes different survival strategies more or less “profitable” in different biomes.
- It limits your species to biomes that you can survive in, which is a big factor of real life ecology and evolution. If your species dies in the absence of oxygen, then you need to adapt to the biomes that do have it or adapt to live without it.
These are some of the big driving forces of evolution!
Other Environmental Variables
There’s also been mention of salinity, pressure, acidity, temperature, and sunlight. The arguments for the inclusion of these is basically the same as the two provided above.
Interface
Won’t all these environmental variables overwhelm the player? Ideally, no. Some of these variables will hardly fluctuate on the microbial level, so we can hide them from the in-game HUD and only display them on the Ecology page of the editor. Also note that some of these variables require senses to detect. If you don’t have thermoreception, you will not see a UI element displaying temperature (or it will just be blank or read “n/a”). Same with photoreception and sunlight. This means that a cell is unlikely to be able to detect all these variables at once.
Microbe Editor Ecology Page
Since I mentioned it, I’ll briefly explain that we’ve had some mentions here and there of having an additional “Ecology” page in the Microbe Editor where you can see what biomes your species is living and thriving in and choose which one to spawn into next. Here is one of the mentions (In-game encyclopedia - #14 by MirrorMonkey2).
Questions
If I forgot to explain anything or something is still unclear please bring it up. Once we finalize these concepts I will write up descriptions on these features and the theory behind them to the wiki.