Bots and Simulations > Evolution and Internet Sharing Sims

On Evolution and Population Decline

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asterixx:
I was not sure whether a topic like this already existed, and I couldn't find one, so I decided to devote my official second topic on this forum   to the issue of evolution and population decline. First of all, I've had a sim running about 50 hours now and I've noticed that overall, average mutations increase as population increases. This makes sense. I've also noticed that with decreases, the relationship is the same, which also makes sense. My dillema is this: How could one expect to see evolutionary changes in a population that remains relatively stagnant? Furthermore, how could a ".totalmyspecies bot" evolve in a way that doesn't lead to the aforementioned "stagnation"? Does it just take a VERY VERY long time?? Perhaps I'm still unfamiliar with this  

Anyway, I was wondering if anyone had any ideas about this and if there are any predictions on the evolutionary patterns/cycle, and things like that. EricL, your 1000 zerbot write-up still astounds me, and was very helpful: Did you save a long-term graphs on that sim? I was thinking about doing an evosim and keeping full record of all of the data to get an idea of the long-term patterns, if such patterns even exist.

Thanks in advance,

Asterixx

Numsgil:
Evolution very often will get stuck in a local maxima (or minima, depending on which way your fitness landscape is oriented ).  Basically they'll evolve to local conditions, shed every last feature that isn't immediately useful, and then stop evolving, more or less.  To prevent this, you'll want to change up the settings from time to time.  Increasing costs is an option, as is increasing friction, etc.

Another solution, if you can, is to run in IM.  Something magical happens when you have different strains of bots competing for control of a local food source.

asterixx:

--- Quote from: Numsgil ---Another solution, if you can, is to run in IM.  Something magical happens when you have different strains of bots competing for control of a local food source.
--- End quote ---

Well, it just so happens that the bot in question was Shrinking Violet 2, and I have been running it in IM since the start. I played around with the costs a little bit but I can't find the right balance: Either 1)the Shrinking Violet 2 is unnaffected by the NRG and cost changes, or if that isn't the case, then 2) I border on wiping out the entire population. I should also mention that I had mutations enabled and maxed.

[attachment=830:Shrinkin...etGraph1.JPG]: A Variation on that pattern repeats over and over again. I hate Veggies!  

Numsgil:
Mostly it just takes patience.  If your mutation rates are too high, genetic drift is stronger than selection, and your bots devolve.  Your goal should be:

1.  Maintain as high a population as possible -and-
2.  Maintain as low a mutation rate as possible (ie: before you lose patience).

A good mutation rate to start at is 1 change per 2 generations, or something in that neighborhood.

asterixx:
Ok, thank you. Enlightening words!

What are your thoughts about the zerobot sim?

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