D&D scifi, thoughts on the evolution of tech & animals

[some bloke]

So I am writing a campaign for dungeons and dragons, and I have just started putting together a part of the setting in which a kingdom was shrunk about 2000 years prior, and stored in a small container. The upshot of this (by my own authority as the author) is that time travels about 10 times as fast within the shrunken kingdom as outside. So to the people outside it has been 2000 years, but to the kingdom it has been 20,000 years.

The Kingdom is isolated from the magic of the world, so has instead developed technology (where D&D typically sits in a fairly static state of technological progression, with swords and bows).
I have decided that the sentient populace has developed to a near-future style of scifi, with modern type guns being the main weapons but with a smattering of more powerful railguns and plasmaguns thrown into the mix, so that side of things is fairly well on its way to completion.
My next thoughts are those of the the evolution of species within such a confined space. Essentially the kingdom is about 5,000 square miles, with walls around it and a ceiling which is perpetually shrouded in cloud, and produces a variety of weather (except clear skies, of course) to keep the ecosystem going, with day & night cycles still occurring due to outside magic. things like water draining away and that sort of thing I will hand-wave away, it doesn't need to be hard sci-fi too much. But will the animals have evolved in such conditions? I would guess anything migratory would have to change its habits, which might in turn lead to changes in the populations of their carnivores and scavengers, as long-distance tracking isn't so important. I don't think 20,000 years is really enough for significant evolutionary changes (enough to warrant more than just a slight change in the description, eg. migratory birds becoming fatter due to a lack of need/capability to move, so moving toward becoming ground birds. that sort of thing.

thoughts?

 

[member 656954]

Because it's magic, you have leeway to do anything of course, but if this population is in a "small container" and they have railguns, what stops them shattering the container from within? Also, if they're near-future in tech, that means they'll likely figure out they are in a jar. Imagine an SR-71 equivalent skimming the roof of their world. That's going to raise lots of questions! And the most likely 'answer' will be, "We want to get out!"

As for the animals, evolution as a response to environmental stress is common, and they'd be under extreme stress inside the jar. The lack of "clear skies" would hamper vegetation that needs it, which would starve those herbivores that eat it. The loss of those herbivores would then starve the carnivores that feed on them, all the way up the food chain...you get the idea, I'm sure. Migratory birds would probably not get fatter, they'd die out because the first generation that slams into the walls is unlikely to reproduce on the terrain they find themselves on, assuming some survive the unexpected - and traumatic - termination of their migration.

Unless there is a magic river flowing through it, there won't be any marine life or shoreline, so whole classes of animals and insects instantly vanish, leading to catastrophic collapse of the food chain that relies on them!

Honestly, worrying about this problem at any level will lead to madness. I'd suggest you liberally coat with handwavium and ignore it altogether

 

[BillTre]

Something to consider is how the shrinking has occurred to your biological entities.
If the atoms were shrunk down, than biology (which is based on precesses going on at the molecular level) could procede somewhat normally. If atoms were not shrunk, then the smaller bodies of animals and other organisms will get simplified as is done in miniturized animals we find today. Here is a paywalled article for example. There are some very small amphibeans and fish whose body parts are simplified because their component cells can't really get any smaller and still function normally due to the molecular mechanisms inside them that they depend upon. There are also some extremely small invertebrates whihc I kow less about. Some smaller bones can vanish because they would be too small if proportional to be a single cell wide for example. The effects on proportions would also be affected. Smaller size would not require proportionately thick bones for support. They could be proportionally thinner. Bone support is based in the bones cross section, such as a thick elephants leg to support its weight, This is not an issue for aquatic animals or plants since they can be neutrally bouyant and get around the issue. If an animal is small enough, it can do away with its specialized oxygen exchange organs, such as lungless and gill less amphibeans and baby fish which can get sufficient gas exchange through their skins. Mutant zebrafish lacking blood cells can survive for several days while they are small (a fraction of a mm across).
Animals on small islands often evolve to smaller sizes, mini-mammoths, mini-possible Homo erectus (the Hobbit fossils). But, sometimes they can get larger.
i am guessing that if the atom size is also shrunk down, then a lot of these changes might not happen (not selected for).

For an ecological comparison, think of an isolated 5000 square mile park and what can be maintained there.
Another comparison would be things isolated on small islands.
I would guess a simplified ecology would work, but the landscape (unless there were some inputs and outputs from the small isolated system) would tend to become more flat from erosion (which can vary depending on things). There would presumably be not plate tectonics or volcanos to produce terrain at higher altitudes.

A story I always liked is Microcosmic God, where some smart guy isolated some small creatures in some kind of container, sped up evolution and selected them for great intelligence (which they evolved in his lifetime), but they were unaware of the outside world and thought of him as their God. They were basically his highly intelligent tools. The story ended before they found out as I recall, but it would have been interesting if they had found out they were being used.

20,000 years seems like enough to me for significant changes to happen under a strong selection scheme. Especially if there is some mutational input (increased rates of mutation, which can be caused in a number of different ways).
The real number to consider is not years but the number of generations when it comes to rates of evolutionary change.

 

[some bloke]

The container is not fragile, so them escaping is unlikely. There is also a gate to exit, but it is under the control of religious zealots who believe that there is nothing out there and to trespass is blasphemy, you know, that sort of thing, so no-one is allowed out.
The roof is perpetuallt in cloud and storm, so no-one has ever made it through.I think I will resort to handwavium for the most part of it - magic plays too big a part to make this too sciency!

 

[member 656954]

I think I will resort to handwavium for the most part of it - magic plays too big a part to make this too sciency!

Sounds like the best way to go, @some bloke. D&D is entirely magic in any event so you are not breaking the canon.