I’m focusing a bit on detailing the rough plans for our macroscopic editor and have revisited this thread. Upon review of this concept, I have a few thoughts.
I do think it’s a wonderful idea to have circulation, respiratory, and digestive rates determine metabolic rates, but I wonder if we can afford to simplify things a bit from the more elaborate model here. This is elaborate enough for me to read through and understand, so I worry it might be a lot for the player to deal with. Even if it starts simply and with few nodes, once those other nodes get involved, I can easily understand if a player completely loses track of things and gets intensely confused after making a simple mistake. It’s elaborate enough reading through it; imagine having to deal with various interconnected parts related to these stats!
Here is an alternative proposal I have based on the premises of this post which I think is a pretty intuitive carry-over from the Microbe Stage.
FUNDAMENTALS
To survive, you need to make sure your metabolic rate meets (preferably exceeds) your basal metabolic costs, established by the anatomy of your organism. This is essentially the same as making sure you make enough ATP to meet your basal ATP cost in the Microbe Stage. Your metabolic rate is defined by three things: your respiration and digestive rates, which are modified by your circulation rate.
To review how things work in the real world (I needed this): your digestive rate influences both how efficiently nutrients are extracted from organic matter and how quickly this process happens. Nutrients are then delivered throughout the body to cells. Cells then breakdown these nutrients via respiration, which is where the respiration rate matters. The rate at which both nutrients and oxygen gets transported throughout your body is the circulatory rate.
So, the whole process essentially looks like this:
- Eat something to get organic material
- Digest that organic material into nutrients, then circulate those nutrients to cells across the body
- Respire oxygen/whatever and circulate that gas throughout the body. Some breakdown of nutrients can happen without oxygen, but the majority of energy is facilitated via aerobic respiration.
- Each cell then breaks down nutrients locally, using respiration to breakdown nutrients.
EDIT: I will say that metabolism, respiration, digestion, etc. are influenced by an immense amount of factors and details. The whole process is much, much, much more complicated than I let on here, worthy of a life’s work of research. This is just a very simple way for us to understand things that hopefully is correct (input from the theory team is welcomed, please!)
THE RATES
Digestive Rate = Digestion is essentially the process which converts organic material into nutrients. It is congruent to the conversion of organic material into resources in the Microbe Stage via lysosomes and such. There are two components of the digestion rate: efficiency (in terms of breaking down nutrients) and time (how quickly food is broken down). They have a positive relationship. An increase in digestion time means an increase in efficiency, while a decrease in digestion time means an decrease in efficiency. So, digesting something quickly means you have quicker access to nutrients, but are much less efficient in extracting nutrients.
Let’s say you are a high-speed predator. You don’t eat all the time, but when you do eat, you eat a lot, and you spend a lot of energy getting that food. You also maintain a lot of high-energy adaptations, such as fast-twitch muscles and an extensive respiratory system. Considering this, it would probably benefit you to breakdown food very quickly, even if it means a loss of efficiency. If you breakdown whatever food you got slowly, you might not have enough nutrients available to fuel the moments in which you burst for prey.
Let’s say you are a grazing gentle giant. You graze on a low-energy food source, so you need to eat all the time, and need to extract as many nutrients from this food source as possible. Considering that, it is worthwhile to have a slower digestive system. If you consume your food source quickly, you lose on nutrients, which- considering your low-energy food source in the first place - isn’t very beneficial in the grand scheme of things.
https://organismalbio.biosci.gatech.edu/nutrition-transport-and-homeostasis/acquisition-of-nutrients-in-animals/
In Thrive
In Thrive, your digestive rate will determine how quickly your organism breaks down organic matter into nutrients. You can generally influence either the rate or efficiency of digestion to suit your playstyle, through means that I will propose in another post.
Respiration Rate = Oxygen is needed as a catalyst for cellular respiration, serving as a controlled explosion of energy. Cells convert whatever nutrients they receive locally, meaning they also need local availability of adequate oxygen. Though there is some exchange between the rate and efficiency of respiration, a lot more emphasis is placed on adaptations which influence the efficiency of respiration. A more efficient respiration rate allows a quicker breakdown of nutrients into readily accessible energy.
Organisms which require a rapid burst of energy or live in low-oxygen environments, such as high elevations or the deep oceans, generally require elevated respiration rates to support their lifestyle. However, there is a certain point where the marginal benefit of extra oxygen absorbed does not justify the marginal cost of additional metabolic costs. This is why you don’t see every single organism in high oxygen environments maintain a hyper-powered respiratory system. It also means that even in low oxygenic environments, there is only a certain amount of oxygen available to be extracted.
Here is some more reading on respiration rates and size: Oxygen Consumption in Relation to Body Size, Wave Exposure, and Cirral Beat Behavior in the Barnacle Balanus Glandula | Journal of Crustacean Biology | Oxford Academic
In Thrive
In Thrive, your respiration rate will influence how quickly your nutrients are broken down into energy/ATP. Various factors can influence respiration rate, including surface area and dedicated organs. Your respiration rate will ultimately be limited by the amount of available oxygen in your environment.
Circulation Rate = Your circulation rate is essentially how fast things that need to get somewhere go in the body. Everything from water concentration, to nutrient circulation, to respiration is heavily dependent on circulation. Most smaller or less complex organisms don’t necessarily need an elaborate or dedicated circulatory system - many jellyfish, for example, get enough circulation from their digestive system to support their (relatively) low energy lifestyle. However, as complexity and size increases, there is a greater need for a more high-powered circulatory system.
In Thrive
In Thrive, your circulatory rate will essentially act as a coefficient affecting either your digestive or respiration rates (or both, though some adaptations might focus more on a specific rate). This coefficient might be neglected at first, but as you get more complex, you will need to supplement your digestive and respiratory rates to meet increasing energy demands.
Other
I don’t think we necessarily need to explicitly represent “ingestion rate” in Thrive, and I think we can afford to essentially lump that in with digestive rate (unless I am neglecting something). Instead, along that line of thought, the way we deal with adaptations surrounding the jaws/teeth/digestive enzymes can essentially be focused on determining how much organic matter you receive from your food items. So essentially, “ingestion percentage” might be a better way to think of things rather than “ingestion rate”.
Say you catch a prey item with 20 organic matter, 10 of it being contained within bones/a exoskeleton and 10 of it being flesh. If you don’t have specialized teeth/jaws, you might only be able to access the 10 flesh you ate. So you would only get 10 organic matter, while the other 10 is either wasted (poop!) or left on the carcass. This extends further on - certain plants require certain teeth or jaw structures as well, and digestive enzymes mind you!
Similarly, I don’t think we should necessarily think of hydration as a “rate” and rather as a resource, similar to how we treat other resources in game currently (if this is what is meant in the OP and I am just misunderstanding the term “rate”, forgive me). I guess a “rate” relevant to hydration is the rate at which you lose water, which I think is an important factor to represent when it comes to amphibians, fish, etc. Beyond that, “water storage” can be a possible factor, though I need to read up on that a bit more.
SUMMARY
So in summary, this is how the process will look…
- Catch and eat your prey/food, which will become organic matter to be processed. The amount of organic matter extracted depends on how much organic matter is accessible to you, based on teeth/jaw structure and digestive enzymes (we should probably rename “organic matter” to be more neutral for the brief period in time where quirky diets might exist early on; it’s ingested matter currently, yes?).
- Ingested matter becomes nutrients dependent on your digestive rate, which is affected by your circulation rate.
- Nutrients turn into ATP/energy dependent on your respiration rate, which is affected by your circulation rate.
And that’s it. A pretty simple system if you ask me. If this is what was meant by the original concept, forgive me - I might not have grasped the entirety of it! If nothing else, this can help us understand how the macroscopic stage can look like in terms of stats and the process of getting energy relative to the Microbe Stage. It should be a pretty smooth turnover.
Also note that this opens up various adaptations we see in real life surrounding the process. What if you want to increase your “organic matter storage”? Get a big gut, like a lot of huge herbivores. What if you want to increase your “nutrient storage?” Put on some fat deposits. The list goes on.
Hopefully this is a robust concept that you guys can see through. I do think whatever model we use will essentially be dependent on the ideas established by NicktheNick’s posts in some way, so I am planning to use these terms in some future concepts I am writing up now. So stay tuned!