Metabolism, Temperature, and Scaling
All agents metabolize their arena. Some agents metabolize other agents. Primary metabolites contribute towards growth, development, and reproduction, while secondary metabolites tend to mediate antagonistic and mutualistic interactions between agents. Increasing temperature increases metabolic rate. Increasing agent size increases the efficiency of metabolic processing while also slowing it down and thus extending agent lifespan. These two power laws roughly cancel to homogenize the total number of heart beats over an agent lifetime across scale.
I first ran into these power laws a few years ago when "Scale" by Geoffrey West was popular here on the forum. More recently after chatting with @mountainFrugal I came across the Metabolic Theory of Ecology (MTE):
https://en.wikipedia.org/wiki/Metabolic ... of_ecology and
https://www.pnas.org/doi/10.1073/pnas.1423502112
Looks like there may be slight differences between plants, endotherms, and ectotherms at each scale but the 3/4 power in Kleiber's law seems quite universal. This makes for the perfect nexus of constrains when simulating a biotorus. The agent size and temperature influencing metabolic rate which in turn regulates food consumption or hunting/grazing cycles. Secondary metabolites further increasing species diversity or niche availability.
One of my original motivations for producing Volution was to be able to watch speciation and extinction occurring over great swaths of time. Smaller agents undergoing a more rapid evolution at a higher speciation rate. Though, the real challenge is reconciling a slow grind of watching an agent in real time with a fast grind of watching whole biotoruses explode in diversity and eventually stagnating or undergoing mass extinction. The first running as 1x speed and the latter at like 10^3-10^8x speed, or up to a million years per day. At some point you run into compute limits and must either slow down or approximate agent interactions. I figure this can be worked out as I go.
Mainly, the goal is to get something interesting to happen in terms of dynamical systems theory. It would be nice to be able to play with stability, phase spaces, limit cycles, and the like while also being able to analyze agent behaviors and perhaps even minds. Then perhaps once the sandbox is "fun enough" I will polish it a bit and sell on itch or steam for like $5.
A ring in a K2 civilization once built is very likely to be populated from the overflow of an existing population (like earth, mars, or other rings). This kick-starts the evolutionary process a bit based on a coalescent view back in time. The time between the emergence of alleles in a population ecology increases almost exponentially looking back to the LUCA (last universal common ancestor). So, migrating a mature ecosystem with agents scaling across many sizes from ring to ring catalyzes the introduction of novel alleles into the future.
Even if our future is unlikely to lead to a K2 civilization that can afford ring construction projects, the project of building a simplified model of agent populations may provide perspective on the rather more complex case of Earth's biosphere. Perhaps a biosphere can be approximated as some linear combination of various biotoruses that fix altitude and biome. Each ring could be thought of as like a terrarium and/or aquarium that maintains homeostasis.