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Survival of the fittest

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Jez:

--- Quote from: shvarz ---There is really no reason to kill "the worst bot", because if it is indeed the worst, then it will die off anyway.
--- End quote ---
I wish that were true, but it's a petri dish experiment, a eutopian existance where manna pops into existance if somebodies pigged the last meal. There are no sharks or tigers waiting in the wings to semi-selectively cull the populations. If my definition of 'worst bot' included cancerous/cannibal/sterile berthas then they are quite unlikely to die off.

--- Quote ---In addition, even in theory there is no way to define which bot is the best or the worst.
--- End quote ---
I can think of definitions of bad behaviour that might have a positive impact on evolution;
*must have 1 baby every x cycles
*must obtain x amount of nrg every x cycles
*must not gain more than x amount of nrg from friends every x cycles


--- Quote ---I would have a disaster event,
--- End quote ---
Could be a good idea, it's not a herd facing the selective pressure of being ambushed by a pride of lions though. I was just trying to think of a way to increase those selective pressures that most animals face for our bots, rather than the unselective pressure that the inhabitants of Pompei ended up facing.


--- Quote ---scale each bot's point mutation rates by its unfitness
--- End quote ---
Interesting idea, does face the same problem that shvarz suggested selecting for worst bot faced. If it is going to be a problem to select one worst bot how are you going to have a sliding scale to rate a population? I would like to see the affect that an idea like that had on a population.

EricL:

--- Quote from: Jez ---If my definition of 'worst bot' included cancerous/cannibal/sterile berthas then they are quite unlikely to die off.
--- End quote ---
DB is all about natural selection, not artifical selection thus there is only one judge of fitness and that is survival and reproductive success over time.  Our own definitions or preconceptions of which adaptations we like or dislike, expect or don't expect is unimportant.  Selection will favor whatever strategy works.

Cancerous population explosions and sterile berthas are temporary aberations, usually due to a single deleterious mutation in a reproduction gene.  I say deleterious because they ultimatly terminate the ancerstrial line.  Sooner or later, they will die off without descendents, the former due to nrg exhasution, the latter as soon as something evolves to take them on.  (If you don't want to wait for berthas to get preyed upon, try a age cost that ramps up slowly.)

As far as canibalism, why shouldn't selection favor it?  Kin selection only matters when there is diversity within a population.  Most evo sims have very little (see my above post) thus the evolutionary value of guaging kin relatedness is close to zero - all bots are close relatives.  We only perceive cannibalism as abnormal because we start our sims with hand-coded bots that have a conspecific recognition gene and then we act surprised when this gene gets selected against.  What woud be truly interesting is the evolution away from canniblism in a population 100% evolved from zerobots. This would require the evolution of some notion of species and selection for conspecfic recognition.  Now that would be something.

Jez:
I understand, probably not the best idea I've ever had   it would be artificial selection. I tend to think of DB as a petri dish experiment, there aren't that many outside pressures on the bot, very often they aren't forced to follow narrowly defined survival strategies. I was considering 'worst bot' as a way to focus bots mutations onto a more closely defined path.

Other methods of creating outside pressure on the bots would be better.

Numsgil:
I would say that "fitness" isn't something that can be defined particularly well by a 1 Dimensional number for a single individual of a species.  Fitness seems to be a multifaceted vector that defines nodes in the phylogenic tree.  Any fitness calculations really only make sense to me as a way to measure positions in a phylogenic tree against a very specific metric.  Having bots evolve against these metrics is ultimately not going to be a fruitful excercise.  The bots will twist the rules to their benefit, but not in ways we'll find particularly meaningful.

However, I do see great merit in providing stronger selective pressures.  Bots have it too easy, and it shows.  Ultimately, I think we should introduce the idea of a "random carnivore".

Every X cycles, the program loads up several individuals from various league positions into the program.  They'll go around wrecking up the place for, say, 1000 cycles, or until 70% of the evolving bot population has been wiped out.  Then they'll all die, and their corpses will float around for food.

Ultimately I think an evolving population needs some extreme selective pressure at some extremely rare times in its history in order to shake things up enough to take the next step.  See Toba catastrophe theory, which points to a large scale die back event that occurs at virtually the same evolutionary moment that Homo sapiens sapiens arrives on the scene.  Coincidence?  Well, the data is pretty flimsy still so maybe.  But the idea stands as plausibly valid.  The key is punctuated equilibrium, and you need something to do the punctuating.  Something big!

As I've said before, I think it tends to be more the unsurvival of the unfittest instead of survival of the fittest.  The rewards at the top are less rewarding than the punishments at the bottom are punishing.  Killing off huge portions of the population from time to time is important in pushing a species forward.  Or backwards.  Or anywhere other than where it is at any rate.

Jez:

--- Quote from: Numsgil ---The unsurvival of the unfittest instead of survival of the fittest.  The rewards at the top are less rewarding than the punishments at the bottom are punishing.
--- End quote ---

I like that! Also the idea of punctuated equilibrium as a form of evolutionary pressure.

Metric pressure = bad, dropping a 'pride of lions' on bots heads every now and then = good!  

Isn't it true that every time we have had a 'new species explosion' it has followed a large scale die back?

I am also familiar with the theory of species extinction following Homo Sapiens spread across the planet, and continuing, unfortunately, to this day. Homo Sapiens is a natural catastrophe, Gaea maybe shot herself in the foot by not having a bigger 'Toba Catastrophe' and wiping us out a bit more completely!

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