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Sexual Reproduction Focus Group

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PurpleYouko:

--- Quote ---If bots are inorganic, sexual reproduction has no analog and we're back to square one.
--- End quote ---
What would make you think that?
There is no reason why inorganic life shouldn't reproduce sexually.


--- Quote ---If we start departing too much, I think we're less likely to stumble on the correct combination that makes sexual reproduction more than a curiosity.
--- End quote ---
Agreed but I don't see any problem with using shots as sperm. It is completely analogous to many higher order aquatic organisms. If your only issue is one of scale of the shots then you are artificially injecting a problem that isn't really there by making assumptions about the nature/size of DarwinBots. By this reasoning we should probably scap viruses too.

The exact nature of the beasts has always been completely open so that they are whatever any one user wants them to be. And that's the way they should stay.
To me they are sometimes little machines and at other times they might be fish in a pond. DarwinBots are undefined so we can't really force them into non-existent niches by insisting on adherence to a reality that in many cases can't really apply.

Numsgil:

--- Quote from: PurpleYouko ---What would make you think that?
There is no reason why inorganic life shouldn't reproduce sexually.
--- End quote ---

We don't know of any non-eukaryotic life that sexually reproduces (I don't even think bacteria are doing it), so we certainly don't have the template, the how, that is important in determining how we want to do sexual reproduction for artificial or alien life.

The only example we have is real life having real sex.


--- Quote ---Agreed but I don't see any problem with using shots as sperm. It is completely analogous to many higher order aquatic organisms. If your only issue is one of scale of the shots then you are artificially injecting a problem that isn't really there by making assumptions about the nature/size of DarwinBots. By this reasoning we should probably scap viruses too.
--- End quote ---

Sperm travel slowly in our frame of reference.  Shots travel quickly in the bots' frame of reference.  Sperm is incredibly fragile and dies easily, which makes long term transmission impossible.  Shots are incredibly impervious until they run out of energy, allowing them to cover great distances.  Sperm has to be placed in just the right spot, and mammals have even evolved an effective injection system (the penis).  Shots just have to touch a bot and their effects are felt.  In real life, the only effective strategy for macroscopic (specifically vertebrate) animals is to get up right close to the mate (or the eggs in the case of external fertilization, but eggs tend to be the same size as the animals, relatively speaking) and fertilize them.  More often than not this involves a coupling.  A coupling not dissimilar to the sort of coupling you get with ties.

Now, smaller critters do do a sort of mass release of sperm and egg, but this would be better modelled in terms of bots instead of shots, especially if we're imagining the more interesting creatures like the fungi.

It is for these reasons that I would support ties and only ties as the basal mechanism for transmitting large amounts of genetic information (such as the whole genome).

Viruses, since you bring it up, are miniscule compared to sperm.  Totally different orders of magnitude.  And while this fact does make fast moving shots somewhat unrealistic, viruses are also quite hardy, adept at surviving and spreading themselves around.


--- Quote ---The exact nature of the beasts has always been completely open so that they are whatever any one user wants them to be. And that's the way they should stay.

To me they are sometimes little machines and at other times they might be fish in a pond. DarwinBots are undefined so we can't really force them into non-existent niches by insisting on adherence to a reality that in many cases can't really apply.
--- End quote ---


I perfectly agree, but this undefined nature doesn't exist on all aspects, only when taken as a whole.  Shots have no natural analog really, you just have to accept them as a throwback to Darwinbots's idealogical predecessor: C Robots.  Ties sort of combine a variety of biological ideas into one mechanism, such as leech like sucking of resources, physical connecting proteins, the elongation of a cell during reproduction, etc.

Sex especially has no context when trying to seperate it from the organisms who participate in it.  Sex is a complex process.  Science is still wrestling with the basic question of "why?".  If we start reinventing how we want our sex to work, it's entirely probable we'll remove a key aspect that is imperitive for sex to become evolutionarily useful, and our efforts will be entirely wasted.

PurpleYouko:

--- Quote ---We don't know of any non-eukaryotic life that sexually reproduces
--- End quote ---
We don't know of any non-organic life form period.
Who knows how they will reproduce if we ever discover them?


--- Quote ---The only example we have is real life having real sex.
--- End quote ---
Ha! limiting ourselves to real life is boring.  
I want to go way beyond what real life can do. I want to explore fantasy worlds as well as real ones.

Certainly sperms (real life ones) are slow and fragile when they move under their own power but they can be packaged up and ejected with considerable force over a short distance. Shots do the same thing. They die too if they don't hit something within a reasonable time frame.

Besides, if my DarwinBots are inorganic, electrical lifeforms then a shot containing a digital code is totally in-keeping with the reality of the sim. It lives as long as it has enough electrical power to maintain it and if it hits a taget during its limited lifespan then it transfers its pattern to whatever it hits.


--- Quote ---Shots have no natural analog really, you just have to accept them as a throwback to Darwinbots's idealogical predecessor
--- End quote ---
I have been pointing that out for years. There are a bunch of things in DB that have no natural analog. Pretty much all the eye based sensory inputs (apart from distance) would fall into that catagory too.

I don't think we should really concern ourselves with making DBs match real life except where that gives us the best chance of something working right. My philosophy is to give them as many avenues as possible to do whatever they need do and let them choose how to do it themselves. Realistic? Not realistic? Doesn't make a lot of difference to me.


Incidentally, some pretty weird stuff happens in real life too.
In some fish such, as guppys and a few other live bearers, the female can carry a package of sperm for a couple of years and use it to fertilise mamy many batches of young. How do they keep the fragile sperm alive? I have no idea. I expect somebody does though. I just never bothered to look for the info.  

Numsgil:

--- Quote from: PurpleYouko ---We don't know of any non-organic life form period.
Who knows how they will reproduce if we ever discover them?
--- End quote ---

Exactly.  We don't know how they'd reproduce.  Not only that, we aren't even qualified to guess.  Biologists still don't understand why sex exists in the first place.  What could possibly be so powerful as to entirely overwhelm The two-fold cost of sex.  There are theories, but few of them have much experimental data to back them up.

With some very real drawbacks to sex, we have to be very careful setting up our DB sex.  We know that real life sex is successful, we just don't know why.  It would seem relatively easy for a group of humans to invent something like sex (say, in an ALife program), miss the point entirely, and create a deleterious method of reproduction.  I would strongly recommend following the only existing and proven method of sexual reproduction as closely as possible.

IMO we need to follow the actual process of actual sex as clearly and perfectly as we possibly can in the hopes that be sheer dumb luck our version of sex can overcome the two-fold cost of sex as well.

Since our organisms are all haploid, we're already facing a rather significant difference with real life.  Given that we may have already taken too great of liberties in this one single regard, we need to proceed very carefully.

If we create a method of sex that does indeed seem to outweigh that two-fold cost for sex, then we could proceed abstracting the process, seeing how far it can be stretched before it breaks.


--- Quote ---Ha! limiting ourselves to real life is boring.
--- End quote ---

While most of life is boring, surely you're not implying that sex is boring!

Carlo:
Nums, it seems to me that you're taking things from the wrong side. The first thing one should ask himself, before doing anything, is: why do I want sex reproduction? A few good reasons to introduce sex reproduction in DB have been formulated in the (helas) past years (I'll list them later); but we can just say that introducing it would change the rules of the simulation and give rise to some desirable effect. What's important with in this plan is that it takes the new feature as a starting point for some (foreseeable and desired) effect.
Now, you're taking things the other way. You say, well, sex repro exists in nature, and it is obviously advantageous (because so many organisms adopt it), though I don't know why. So if I want to introduce it, I have to copy it as accurately as possible from nature, so that I'm sure not to leave out something important.
There's something not convincing me in this argument. If you don't know what's the advantage of reproducing sexually, then you may want to investigate about it; to do so with an artificial life simulator, you should take as a starting point a very general set of rules - flexible enough to allow many different types of reproduction - and observe the outcome of natural selection. The result may consist in organisms with, say, one, two, n chromosomes; or no chromosome at all, but just exchanging floating dna or single genes. In any case, you're interested in the result, whatever it is. You want to explain sexual reproduction, but you don't actually need it. It is your goal, not your starting point; hence you should not code it directly in the simulation.
At the same time, you say you want to hard code sexual reproduction in the simulation - just as a rule that you need for new complexity. This would make sexual reproduction a starting point, not a goal, and you should be able to list the benefits of introducing it.

Now, it's been a long time since we first thought about introducing sex in DB. There are a few reasons for this:
1) many of the organisms we're most familiar with (expecially those showing complex behaviour) reproduce sexually. It is not to say that then reproducing sexually is good; but, as DB should show a parallelism with the real world, it is good for DB to reproduce some major traits of the world, sometimes even directly coding them;
2) sex should enhance evolution, by letting the result of good mutations which may have taken place in different branches of the evolution tree mix together;
3) sex, requiring compatible DNAs to mix, gives rise to real species and speciation, which always lacked in DB. The very concept of species is blurry without sex;
4) sexual selection becomes possible, though still hard. The criteria generally used in the choice of the partner influence evolution.

Now, given these points (2,3,4), it is possible to have an idea of what this kind of sexual reproduction in DB should look like. For 2), sex repro should be able to mix dnas of two (or more) individuals, transferring some genes from one to another, or mixing the genes in a new individual; 3) is the consequence of a reproduction mechanism which requires the source dnas to be similar enough to produce a well-formed destination dna; 4) requires robots to be able to make some kind of choice of the partner(s).

These requirements seem to be not too distant from what the actual .sexrepro command does. The least fulfilled is 4): .sexrepro is very weak in that, partially because it is maybe a too simple mechanism, but also because of intrinsical limitations of DB: things in it simply go too fast and good communication between robots which aren't tied is too difficult. Which should be the elements for a good partner's choice?
Also the algorithm which mixes the two dnas is probably too simple - though working, and not too difficult to improve. Has anybody tried to run extensive simulations making use of (and exclusively of) sexrepro?

Anyway, my point is simply that, before thinking of adding features to DB, one should know exactly what he needs.

Bye,
Carlo

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