Metabolism

In the previous experiments, Creatures were obtaining Energy directly from the sun, or from the Ground. In this experiment, we will provide 2 sources of energy for the Creatures: the Ground and another Creature, i.e. by eating another Creature. What is called Metabolism is actually the efficiency of the Creature's body to convert one or the other source of energy into its own internal Energy.

This experiment will not be easy. I have been trying to obtain a stable population of creatures with different metabolism co-existing together for some time, without success. But let's try again with a very simple simulation model.

Usually each experiment I have posted takes me 2 to 3 weeks to test and tune. The process is usually: start Evo(rand), make some parameter changes, let it run half a day, and based on the results make another test. The various tests actually help to better understand the parameters that affect the evolution. Let's see if I have better results with this test.

Configuration

In this test I add 2 more parameters to the Creature. Those parameters are used to simulate a metabolism which is either adapted for absorbing Energy from the Food in the Ground, or from another Creature. The first parameter (FoodMtb) is read from the DNA, and the second parameter (CrtMtb) is calculated from the first parameter:

Finally, those 2 parameters are used for the 2 Actions available for the Creature to obtain Energy:

First Results

The results I have obtained in the first tests were:

• A large percentage of the population starts eating the other Creatures, till they eat all the other Creatures, and then die of having no more source of Energy.
• The Eat Creature action remains performed by a minority of the population.

By changing the Eat Creature Action a bit, by allowing a Creature to eat all the Energy of another Creature, this is what I obtained:

We observe a population distribution similar to the Kill test: each Specie is occupying a portion of the territory, with a no-man's land in-between. It seems that the Creatures are using the "Eat Creature" action as a way of protecting their territory, and not as an alternate source of Energy. This is further confirmed by the statistics per Specie:

We can see that CrtMtb remains low at 0.1 for all Creatures, which confirms the earlier assumption: Eat Creature is used to protect the territory from invadores, but not as a source of Energy.

Final Results

To avoid this unexpected behaviour, I have changed the Eat Creature Action to prevent killing the target of the Action. This is done by preventing the Creature from eating all the Energy of its target:

I have also changed the maximum number of Species to 3, to make the interpretation of the statistics a bit simpler. And then, finally, the unexpected occurs:

• Part of the population has their metabolism specialised in converting Energy from other Creatures.
• This specialisation is common to all Creatures of some Species (Species 1 and 3), and the other Species have their metabolism specialised in converting Energy from the Ground (Specie 2).

• The Species with a metabolism specialised in eating Food from the Ground have a behaviour specialised in searching Food.

• The Species with a metabolism specialised in eating Creatures have a behaviour specialised in eating Creatures.

• And those Species splitted quite early in the genealogical tree: Species 1 and 3 on one side (creature eaters, purple and red) and Specie 2 (ground eaters, green) on the other side.

Finally, here is a little video showing the creature eaters (those with a little red line moving toward their prey) and ground eaters (the smallest of the creatures seen). In this video we follow one of those creature eater. When the size of the creature becomes suddenly smaller it is when it just gave birth, and we can see the offspring moving away.

Any conclusion?

In this experiment we have managed to simulate different specialized Species, some specialized in getting their Energy from the Ground (like herbivores) and others specialized in getting their Energy from other creatures (like carnivores). Both not only have a behaviour adapted to their speciality, but also their internal attribute (i.e. the metabolism). Such specialization requires multiple changes in the DNA, which is certainly the reason why it takes many generations before it appears within the population.

However such co-existence is not very stable, and we can see this from the statistical graphs:

Finally, here is an alternative to the same simulation (under construction).