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Author Topic: Evolution?  (Read 1601 times)

Red Diamond

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Re: Evolution?
« Reply #15 on: August 11, 2020, 11:03:05 am »

Quote
  If it did happen the creatures would sometimes become too cautious and stealthy for the player to find rather than dying out.

That's not really how evolution works. What you're describing is differences in behaviour which are largely set by fixed tags like [LARGE_PREDATOR], [BENIGN] and so on. And yes, species that do not fear the player may eventually go extinct just like they did in real life (see the dodo bird or one of many predator-free insular animals really). So, in a way, the presence of a murderous player naturally selects for fearful and fast creatures. Selection just happens at the species level rather than the intra-population level.

At least, in theory. In practice, just like in real life, evolution is largely dominated by random drift. The way megabeasts gradually go exctinct despite having much better fitness (stats) than most other species is almost a textbook example of drift dwarfing selection in magnitude.

Megabeasts go extinct because megabeasts do not reproduce very well.  Their stats aren't good enough to make them unkillable enough to compensate for their lack of fertility.  Megabeasts are unfit creatures in evolutionary terms, or rather they were fit for the world before civilized creatures with weapons existed that would occasionally succeed in killing them; they became unfit as often happens.  Drift has nothing to do with it.

Normally there is a diversity among creatures in their relationship to humans, some creatures are more anti-human than others.  If a creature is constantly hunted, the creature develops an inherent fear of human beings, conversely if the creature benefits from human presence it develops an inherent semi-tameness.  The reason is that there is an initial diversity among creatures before humans arrive, the human presence selects either for pro-human or anti-human creatures among the population until there is uniformity in attitude according to on balance which is the best option. 

How evolution works is that genetic drift creatures diversity in neutral traits than then become important traits as the environment changes.  The arrival of humans make their inherant attitude to humans a non-neutral trait.  So before the creature dies out, the creature would normally develop a wary attitude to humans and would become harder to find as a result; since the tamer creatures got eaten first.
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Nopenope

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Re: Evolution?
« Reply #16 on: August 11, 2020, 03:01:55 pm »

Megabeasts do reproduce fine though? When you put two rocs together they have no problem starting an entire population. The only problem is that there aren't so many of them, it's not something to do with fertility. Small population size means you're more susceptible to drift. Anyway I don't think pushing analogies this far in a computer game is that productive.
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FantasticDorf

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Re: Evolution?
« Reply #17 on: August 11, 2020, 06:40:22 pm »

Megabeasts do reproduce fine though? When you put two rocs together they have no problem starting an entire population. The only problem is that there aren't so many of them, it's not something to do with fertility. Small population size means you're more susceptible to drift. Anyway I don't think pushing analogies this far in a computer game is that productive.

Megabeasts can only fill the void of the maximum megabeast cap, hence you'd need the entire world's worth of dragons and to slay all other megabeasts in order to have a viable large population you can cull some traits out of, beside the obvious caveat of waiting a long time between generations with their maturity out of the child state.

Maybe you simply want the amber eyed and dark scaled dragons of dwarfy volcano mountain, amongst balancing out all the other fun the game tries to throw at you, maybe resting on your laurels as dominant and prosperous to the point of boredom mountain home.
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Capntastic

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Re: Evolution?
« Reply #18 on: August 11, 2020, 09:06:51 pm »

Toady discusses evolution and inheritance in the latest podcast, and I mention this thread. 

http://www.bay12games.com/media/Dwarf_Fortress_Talk_25.mp3  About 36 minutes in!
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Red Diamond

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Re: Evolution?
« Reply #19 on: August 12, 2020, 01:38:23 pm »

Megabeasts do reproduce fine though? When you put two rocs together they have no problem starting an entire population. The only problem is that there aren't so many of them, it's not something to do with fertility. Small population size means you're more susceptible to drift. Anyway I don't think pushing analogies this far in a computer game is that productive.

They do, but their rate of reproduction is generally lower than the rate of their being killed off, so my point stands.  They actually similar to rhinos when you think about it, creatures not used to being killed off in large numbers cannot cope with the introduction of human predation and go extinct. 
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Malroc The Valiant

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Re: Evolution?
« Reply #20 on: September 01, 2020, 11:50:43 am »

Red Diamond the evolutionary biologist over here, laying down da facts. What a great thread.

In my opinion there shouldn't be evolution because Dwarf Fortress is a creationist world. When the myth arc is fully implemented living gods will walk the mortal realm and everything. I don't really see a need for evolution, lore wise. It is a cool idea though, I just feel like it'd be pretty mechanically difficult and not the most thematically relevant. But that's just my opinion. 
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Starver

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Re: Evolution?
« Reply #21 on: September 01, 2020, 12:13:03 pm »

It might depend what you sphere of influence you find your fortress sitting in... ;)
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Eniteris

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Re: Evolution?
« Reply #22 on: September 03, 2020, 07:45:21 am »

Normally there is a diversity among creatures in their relationship to humans, some creatures are more anti-human than others.  If a creature is constantly hunted, the creature develops an inherent fear of human beings, conversely if the creature benefits from human presence it develops an inherent semi-tameness.  The reason is that there is an initial diversity among creatures before humans arrive, the human presence selects either for pro-human or anti-human creatures among the population until there is uniformity in attitude according to on balance which is the best option. 

This is technically true, but usually they don't evolve to fear humans; they usually just die out instead, see: many island-based flightless birds. This is called Island Tameness, where animals that don't have predators are not wary of introduced predators (including humans). Animals with natural predators would retain some wariness, and potentially evolve to fear humans, but I would guess that this would only occur if humans are not actively hunting them.

Dwarf Fortress already simulates microevolution in terms of genetics for fat, muscle, size, color, and if you selectively kill animals of one color, you can (potentially) "evolve" a species to be some other color. Any more detail would likely be superfluous and have minimal impact on gameplay.
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Starver

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Re: Evolution?
« Reply #23 on: September 03, 2020, 08:08:32 am »

I remember I used to carefully assess my animals and initially slaughter all but the one of each gender I felt were more bulky (either/or the muscalature/fat, depending on what I was given to work with) for an attempt to evoke pedigree stock husbandry.

Not sure I actually got anything out of it, but that was in the days of sporewise-breeding and prior to gelding also being a thing, so I was never sure about parentage being ever so certain with only caging being a sure prophylative at all times before actual death.

But it made me feel I was doing something right, in amongst all the other wild and wacky things I try to do. ;)
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