This project was inspired by the youtube channel carykh. He created a tool called evolv.io and made some Youtube videos showcasing it. It is basically a very crude simulation of little creatures in a 2D world which are controlled by a neural network. They reproduce which will create offsprings with slightly mutated neural networks. Over time the best adapt creatures out compete the others and reproduce. I wanted to create a similar simulation but get rid of some of the things I didn't like about the original one. Over time different mechanics got worked into the simulation but most of them seemed quite arbitrary which - in my opinion doesn't make for a very good simulation of evolution. So I did what any enthusiastic developer would do and created my own simulation.
It would be a nearly impossible task to eliminate all arbitrary decisions. In the end you will have to work with some assumptions if you don't want to simulate a system on the atomic level.
So I created creatures which were made up of organs. There are two special organs. The body and the brain. Each creature has one and only one of these. All others organs could be added and removed via mutation. The brain contains a neural network with a single hidden layer and the first generation would have random weight initialised. Some organs could sense and some could act. For each sensory input the brain provides an input neuron to that organ while each actor would have its own output neuron. The body would take care of the mass attribute which is the resource the creatures need to stay alive. If they drop below a certain threshold they die. Each organ takes up energy each tick depending on how "poweful" it is. For example creatures can mutate eyes but eyes with a wider f.o.v. would cost more mass each tick. Mouths can be of different size too.
While only the brain and the body are a strict must-have, a creature without a mouth and a reproductive organ is not of much use. Those creatures will eventually die and not have any offsprings. Apart from creatures with only a reproductive organ which would at least have a chance of creating offsprings with a mouth.I planned on developing a lot more