The Cavern (Seed world Evolution Game)

Hey everyone, welcome to my second game!

This is an evolution game, not like Path of the Wild however and much less active on my part while I focus on the Twilight Realm.

The premise of this game is that a random group of organisms was dropped onto a planet that is nearly entirely caves. How can that be? You may be asking, and the answer is that while there is a surface, it is about as hospitable to life as the peak of Mount Everest, if less frosty.

Every round, each creature can be evolved once by a player. The rounds will be determined once every creature has an evolution. If a species splits (for example, into lizards and snakes) each branch may be evolved once per round by a player.

No scientific names necessary, but please do give it a common name. A description of the changes made is necessary, and only small changes are allowed per round. So no legs to wings, but maybe a small gliding membrane. Evolutions also must make sense, so a giraffe evolving said flying membrane would not be allowed.

And, so that everything doesn’t immediately die out, a giant, near continent sized valley has formed on one part of the planet, allowing photosynthesis… for now, but the valley is slowly closing.

Now, for a list of starting organisms! Please recognize that these were mostly randomized (only diatoms and copepods were placed intentionally), and that no starter kind of organism should immediately die out, and should leave descendants of some kind.

The list is:

  • Nautilus
  • Shoebills
  • Glowing Mushrooms
  • Armadillo
  • Caecilians
  • Mutant Ghost Frog
  • Yawunik
  • Poison Ivy
  • Clouded Leopard
  • Kiwi Bird
  • Brachiosaurus
  • Brittle Stars
  • Cave Aphids
  • Hatchetfish
  • Candy-Striped Hermit Crab
  • Rhinos
  • Crab-Eating Fox
  • Hawksbill Sea Turtles
  • Crested Groshawk
  • Ermine
  • Ringtail
  • Dogwood Tree
  • Guam Rail
  • Atlas Bear
  • Warrah
  • Chameleon
  • Inciviosaurus
  • Nursery Shark
  • Diatom
  • Copepod

Some notes on creatures you may not know;

Caecilians are amphibian snakes, even have venom glands

Mutant Ghost Frogs are a species of frog mutated by pollution. They have clear skin, mostly clear organs, and pure black eyes. They seem to be able to function as normal frogs.

Yawuniks are an ancient arthropod like species, with long, slender, blade like ‘fingers’ that drift in the current as the Yawunik hides in coral or on the sea floor. These fingers can construct around and slice up prey, and then draw the pieces in where they are crushed by tooth-like protrusions on the arms before being eaten.

The Warrah is a type of Island Wolf

The Inciviosaurus is a dinosaur with buck teeth. Kind of raptor-like in build, though I believe it was a herbivore (not 100% confident)

I hope you enjoy the game! If you have any questions, please ask.


are there seas or oceans?

Ah, I knew I forgot something!

There are many underground oceans, as well as half of the Valley is covered by water, a sea covered in diatoms (plankton)

what is happening to the valley?

yes i think brachiosaurs would do quite well in cave environments… not likje they’re the largest creatures to ever exist on land or anything.

The valley is slowly closing up - the basic Idea is that the Valley is being eliminated, slowly growing smaller and smaller

Yes that is one of the reasons for the valley zenzone - most of these organisms wouldn’t survive if just slapped down into a cave environment, so the valley is so that they hopefully have enough time to adapt to a cave environment before it closes up. I did laugh though when I randomized it up and that’s how it turned out

how do we do the mutations

Really however, though you do need…

  1. A reason for the adaptation
  2. How it realistically developed
  3. Where this new creature optimally lives

And also basic things like what the adaptation is and a name for the new creature. Remember, only one new adaptation per lineage (or lineage split) per player per round

I honestly might just change the ‘per round’ thing to you can’t adapt a creature a second time until another player has adapted it in some way


imma be op after evolving mycelia communication networks

Ancestor: nurse sharks
Common name: pool sharks
Mutations: better smell and hearing, at the cost of blindness. They use these senses to spicificly hunt at times other than midday, when the sun is out and bright (the valley walls would cast shade during every other hour of the day, making it close to twilight, sight and photosynthesis would work for 8 or so hours of the day, but water would be murky and sunburns a non-issue). This strategy is spicificly to avoid stampeding brontosauruses and scavenge without being attacked by Atlas Bears. During the brightest third of the day they swim into the vast underground oceans and sleep undisturbed. Anything that ventures down there is at risk of being eaten. They also have a suction attack mostly used against small prey, just like their ancestors.
Size: up to ten feet (3 meters roughly.)
Habitat: any warm salt water in the valley, shallow underground seas nearby.

How’s that?

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That’s perfect! Exactly what I meant by this kind of entry.

So just so I am clear on it, it spends most of it’s time in the shallows, scavenging and hunting, and then retreats into caves to sleep?

Yupp. It’s bite isn’t too strong but It can suck up basically anything that fits in its mouth. Two things:
1: I’m going to edit it and add some statistics like size.
2: are the caves anoxic? If not will they become anoxic when photosynthesis stops happening

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Currently, no, they have a fair amount of oxygen, at least around the valley.

The plan is maybe adapt things like diatoms to photosynthesize using light from glowing mushrooms to keep up the waters oxygen levels

But doesn’t the ecosystem still need to take energy from an outside source to prevent it from completely losing energy?


Chemosynthesis, transfer of genes from bacteria to multicellular organisms while rare can happen, so chemosynthetic glowing mushrooms from gene transfers to the mushrooms, to diatoms and other photosynthesizing plants to decomposing mushrooms

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I’d say symbiosis is more likely. Like a tube worm.

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Definitely as an intermediate stage, but I would eventually like to have them be able to do it themselves

Why though is that the end goal? It’s not more efficient I think. It’d be cool, but I don’t see enough evolutionary pressure.

Hmm, you are probably right on that front

I’m more used to thinking in this mindset for lithotrophic organisms, which it likely would be more efficient for, but for purely chemosynthetic organisms you may be right that it would be better off just leaving it at symbiosis

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Why don’t I make that now:

Ancestor: Glowing Mushrooms
Name: Cave Lights
Description: Mushrooms that have adapted in symbiosis to several species of chemosynthetic bacteria, gaining energy from them in a similar way to tube worms, in return for a safe place to call home. They are slowly making their way to cave systems worldwide, spreading through their mycelium and able to live almost in any cave environment. Due to their abundance, and the lack of organisms that eat them, there hasn’t been any selection against their glowing, and so they still produce a glowing light, in a range of different colors