Pangaea
Contents:
Introduction
Pangaea is an extension of/response to Phanerozoon. My objective is to take the basic format of the original, but to start from a unicellular LUCA, with multicellular life evolving only gradually, and also to encompass the whole tree of life, i.e., not just mostly eukaryotic, mobile heterotrophs, but sessile autotrophes like plants, sessile heterotrophs like fungi, diverse offshoot clades like protists, and hypothetical clades filling niches that are rare or absent in our world, like mobile, multicellular autotrophs. I also want to add a geographic and geological dimension.
There is a tension between simplicity and elegance and granular simulation, and while I generally prefer the former over the latter, I am still trying to find the right balance between the two. This page is very much a work in progress.
How to play
The game has no GM, and is played remotely. Initial setup requires a blank world map and a suitable place for recording player actions, like a Discord server or forum thread. You will also need a flexible random number generation method. The game is divided into rounds. Each round lasts 24 hours. At the beginning of a round, one player rolls a dice (or generates a random number) to choose a random event from the Random events table. Players then follow the instructions for that random event. During a round, players may take up to three actions to evolve new species--really families of species or entire clades--or to alter the geology of the world. A player may take a fourth action if they also draw a picture of a species that hasn't been illustrated yet. Each round represents roughly ten million years of geological time (maybe more in the early game before multicellular life evolves).
At the start of the game, the world map is blank, the global average temperature is 15 degrees C, the atmosphere is devoid of oxygen, and the only species available to evolve is the LUCA of all future life on this world, a single-celled microorganism with the adaptations extremophile (thermophile), autotroph (chemoautotroph), and anaerobe. It is sometime in the murky middle of the local Proterozoic eon, long after the beginning of life, but long before the first multicellular organisms that will leave fossil traces. On the first round, instead of a random event, the world properties are chosen as laid out here.
If you are playing as part of a larger campaign, continue play until at
least one approximately human creature has evolved. You may wish to
shorten the nominal turn length to anywhere from 1 million to 100,000
years after you reach Ad-hoc tool use. Otherwise, play can
continue indefinitely, or mounting geological catastrophes render your
planet uninhabitable.
Player actions
Player actions can alter existing species ("evolution actions"), or alter the physical world ("geology actions"). Unless otherwise noted, you can do any action any number of times per turn. This includes:
- Create a new species by applying an adaptation to it. Choose an adaptation from the list of available adaptations (either one which seems interesting to you, or at random), and choose a species that evolved on a previous round to apply it to. This creates a daughter-species branching off the main species, which continues to exist. You may remove an adaptation instead (if it is removable), or apply an adaptation and remove an adaptation as part of a single action. You can't modify a species that only came into existence this round, but you can evolve multiple daughter species from a single parent in the same round.
- You can add two or more adaptations to a single species, with the same restrictions as above, but any adaptations beyond the first can only be a basic adaptation (found in the Basic unicellular adaptations table for unicellular species, and the Basic multicellular adaptations for multicellular species). This counts as multiple actions--two, if you are adding two adaptations, three action if you are adding three adaptations, and so forth.
- Target a species for extinction. Roll a 1d6; on a 1-5, the species is extinct. On a 6, the species goes extinct, but an offshoot survives with a new random trait chosen from among available basic adaptations. You can't target a species for extinction in the same round that it evolved. Also, extinctions only take effect at the end of a round: you can always evolve a species if it was alive at the beginning of a round, even if a random event or a player action renders it extinct later in that round.
- Resurrect a Lazarus taxon. A species that was thought extinct before has actually survived, or perhaps been resurrected by some kind of spacetime anomaly or alien intervention. If this species went extinct one or two rounds earlier, this counts as a normal action. If this species went extinct three rounds ago, this counts as two full actions. If this species went extinct four rounds ago, this counts as three full actions. If this species went extinct five or more rounds ago, this counts as four full actions, and thus you can't take this action unless you draw a picture for an extra action point. No matter what, you cannot take this action more than once per round.
- Alter geology. You can fill in a blank area on the map that's up to 2,000 px square with any terrain you like; or, if it's an area that has already been filled in, you can raise or lower the terrain in that area a single level. You can't alter an area another player has already altered this round. For more detailed explanations of how this works, see Altering geology.
- Special geology action. You can take a special geology action, which has a more focused and often greater effect. Choose a special geology action from the Special geology actions table. As with altering geology, you can't use special geology actions on an area another player has already altered this round.
Once you take an action, describe how it happened with a sentence or two. Justifying actions narratively and giving them context in the world is the core of gameplay.
In a Discord server or other context that allows it, you may want to format evolution actions as individual replies to earlier messages about that species, in order to make it easier to keep track of their history. When applying an adaptation, you should include the name of the new species, the name of the parent species, what adaptation(s) it is gaining or losing, and a short description of how the adaptation occurred and/or the new appearance/behavior of the species. I recommend the following format:
- Trilobite (+reduplicated body part
(abdominal segments)) <- Parvancorina
One population of Parvancorina develops an extended segmented body, with individual armor plates and a distinct three-lobed structure. The result is the trilobite, which lives on the floor of warm, shallow seas.
For geology actions, you should copy-paste your alterations into a full-sized image of the world map, so other players can use it as a base without having to merge different versions of the map (see Altering geology, below).
Trilobites were a diverse class of arthropods that thrived in the lower Paleozoic. "Species" in Pangaea represent whole families of closely related organisms like this, though how diverse they are exactly is up to your imagination (and your art skills). Not that your illustrations need to be as high-quality as this one!
Applying adaptations
Adaptations are grouped into categories, and within each category, some restrictions may apply. For example, as you might expect, unicellular adaptations only apply to unicellular species, while multicellular adaptations only apply to multicellular creatures. Some adaptations are mutually exclusive: a creature is usually either a heterotroph or an autotroph.
Many adaptations have prerequisites. For example, the taproot adaptation requires the root system adaptation. If a species has both, you cannot remove the prerequisite adaptation while evolving a new species, unless you also remove the adaptation that depends on it. During an ordinary evolution action, you can always remove one additional adaption to create a new species, but only if that adaptation is a prerequisite to an adaptation you are also removing that turn, and no other adaptations the species has also have that adaptation as a prerequisite. For instance, you could remove both flowers and seeds from a species that has only those two adaptations; but you could not remove seeds if the species also had the adaptation fruit, which depends on seeds also.
Some other adaptations are irreversible. These adaptations usually reflect major changes in body plan that become inextricable parts of a species' overall form or metabolism. An example of this would be bilateral symmetry. Having evolved a fundamentally bilateral body plan, few or no animals have ever subsequently dispensed with it. Animals that have evolved, e.g., radial symmetry, like the starfish, have done so as a special case within the broader category of bilaterians; and other asymmetric animals, like the flounder with its migrating eye, are bilaterians with some incidentally asymmetric adaptations based on a bilaterian body plan. Irreversible adaptations are noted as such in the tables of adaptations.
When the game calls for a random adaptation, use a random number generator to choose an adaptation from the Basic adaptations table. These adaptations represent more genetically superficial, niche-filling adaptations, and are never irreversible, nor do they act as prerequisites for other adaptations.
Optional rule: Fixed extinction rate
If you have a convenient way of storing the list of living species like a spreadsheet, you can remove the ability to do targeted extinction actions as normal, and instead implement a fixed extinction rate rule: for every species extant at the start of a round, roll 1d20: on a 1-5, the species goes extinct (but can still be resurrected as a Lazarus taxon); on a 6-20, nothing happens. This rule should keep the number of species manageable, while allowing players to focus on other actions like evolving new species and altering the geology.
Altering geology
The world starts as a blank image, 1000 pixels wide and 500 pixels tall. We use a Hammer projection since it is equal-area; this means there do not have to be complicated rules to adjust for how much land geology actions are permitted to alter near the poles. The Hammer projection is also accepted as an input in G.Projector, a tool that can re-project the map into other projections, or change the central meridian. Altering the projection can be useful to avoid common traps of fictional map-making, where cartographers often unwittingly use the shape of the drawing surface to guide the shape of their coastlines--producing squared off continents to fit squared off paper, for instance. At 1000 px by 500 px, the 15-degree graticules in the image below are about 1700 km apart at the equator, assuming an Earthlike world. This corresponds to about 45 pixels.
The image above shows one way you can mark terrain
features. There are five elevations that must be tracked: deep ocean,
i.e., dense
basaltic crust without an overlying continental landmass; shallow
ocean, i.e., continental
shelf, granitic continental crust which is relatively low-lying and
has been flooded either due to subsidence or a rise in sea levels; low-lying
land, which represents any kind of plains, coastal plain, or even
rough terrain which is not high enough to alter the local climate; upland,
like plateaus and low-lying mountains; and mountains, in this case
representing specifically young and very elevated mountain ranges, or
extended regions at a very high elevation. In a normal geology action,
terrain can only be raised or lowered a single level: from deep ocean to
shallow ocean, from shallow ocean to low-lying land, from low-lying land
to upland, or from upland to mountain; or any of these in reverse. These
elevation changes can represent many different kinds of geological
activity: subsidence or uplift due to volcanic activity, the rebound of
land after the melting of an ice sheet, erosion, a local spell of
volcanism due to a minor hotspot or a nearby convergent plate boundary,
the raising or lowering of sea levels, or the deposition of sediment by
water or wind. For ice sheets, the underlying terrain is instead shown in
grayscale. Fault
lines, whether they represent convergent or divergent plate
boundaries or some other kind of discontinuity, are marked in dark red
lines. Any area of the map completely enclosed in fault lines is its own tectonic
plate.
Special geology actions
The following actions are available as special geology actions.
| Action | Effect |
| Create/remove fault | Add or remove fault lines that are in total no more than 50 pixels in length. Subsequent motion of tectonic plates will determine exactly what kind of fault this is. |
| Continental drift | Shift a tectonic plate by up to 30 px. As part of a continental drift action, you can specify how landforms evolve along the margin of the tectonic plates affected, up to 50 px on either side of the fault line. |
| Create/destroy major hotspot | Create a major hotspot beneath the oceanic crust. Speckle the plate with islands as it moves over that hotspot during future rounds, or create a single large island if the plate is stationary for several rounds. |
| Orogeny | Add mountains up to maximum elevation, anywhere on a continent that's being pushed into a convergent boundary, in a region up to 3,000 px square. Weak spots in the crust can cause buckling and flexing even well away from fault lines, with brittle crust, at geological scales, as much like fabric as like rock. |
| Flood basalt | A major episode of volcanism floods a region. You can raise the terrain in a region up to 4,000 pixels square; the global temperature increases by 1 C. |
| Bolide impact | A large asteroid impacts the planet; mark an impact crater up to 5 px in diameter. If it hits land, dust from the impact and from massive fires decreases the global temperature by 1 C. |
| Outburst flood | Scour out channels from the margin of an ice sheet to the nearest sea, up to 100 px in width. |
Continental drift
Plates generally drift in roughly the same direction for many millions of years, driven by convection currents in the mantle of a tectonically active world. This motion is not smooth and continuous however, and has a great deal of variation.
Where oceanic plates meet oceanic plates, one will subduct beneath the
other, creating an upwelling of volcanism at the plate boundary, and,
frequently, island arcs and archipelagos like Japan and the Philippines.
Where an oceanic plate meets a continental plate, it will subduct, as in
the Pacific Northwest of America, creating similar volcanism in the
continental landmass, and with islands and small landmasses embedded in
the oceanic plate frequently collecting on the margin of the continent.
Where two continents meet, as at the Himalayas, the result is usually a
large region of mountain-building.
Where two plates recede from one another, the result in the ocean is a
mid-oceanic rift, like the Atlantic ridge, and rift valleys in
continents as in East Africa.
None of this behavior must be imitated in the history of your own world. These are guidelines and advice to facilitate creativity, not hard and fast rules.
Global temperature and ice sheets
The average global temperature starts at 15° C. For each degree below 15° C, polar ice sheets will cover land to about six additional degrees of latitude--so while at 15° C there are no polar ice sheets, at 14° C, ice sheets extend from the poles to 94° N and 94° S; at 13° C, they will extend to about 88° N and S; and so on. When the average global temperature reaches 0° C, all land may be covered in ice sheets, though the seas may still be warm enough to support ice, and the equatorial oceans in particular are likely to be ice-free. At -5° C, the whole world is covered by ice at least part of the year; at -10° C, the ice is too thick to support photosynthetic life, and all photosynthetic life will die, in addition to every species that relies on photosynthetic life as part of its food chain. If somehow your plant gets to -20° C, life on your world has gone extinct, and the game ends.
Similarly, if the global temperature is higher than 40° C, the climate will become unstable; at the end of each round, the temperature of the planet will increase by 1° C. If the global temperature rises higher than 50° C, it will increase by 2° C, and above 60° by 4° C. Additionally, if the global temperature is higher than 60°C at the start of a round, you must roll a mass extinction event: roll 1d6 for every species. On a 1-3, they go extinct. On a 4, they survive unscathed. On a 5, the original goes extinct, but a surviving offshoot gains a random adaptation. On a 6, two surviving offshoots are created instead of just one. If the global temperature reaches 70° C, life on your world goes extinct, and the game ends.
Oxygen Catastrophe
At the beginning of the game, the atmosphere of your world is anoxic and weakly reducing; most life is some form of chemosynthetic autotroph, and any oxygen that does get added to the environment quickly reacts with iron or other elements and is sequestered. For each species with the autotrophy (photosynthetic) adaptation at the end of a round, the Oxygen Catastrophe counter increases by 1. When it reaches 100, the Great Oxidation event occurs instead of a random event at the start of the next round. Each player may choose one anaerobic species with one extremophile adaptation to preserve. All other anaerobic clades are wiped out as the atmosphere shifts to one that is toxic to them.
Biomes
TBD
Tables
World properties
When creating a new world, choose a random gravity between 10% Earth's gravity and 150% Earth's gravity; choose a day length duration from 6 hours to 200 hours; choose a random axial tilt between 90 and 0 degrees; and choose a random number of large moons (moons large enough to be rounded by gravity) between 0 and 3.
Primary body
The primary body the world orbits is:
- An M-class star
- A G-class star
- A K-class star
- An M-G binary
- A G-K binary
- A gas giant.
If you rolled "gas giant," re-roll for the giant's primary, treating a 6 as "roll again." "Axial tilt" becomes the gas giant's axial tilt, and your world orbits it around its equatorial plane. Any large moons your world has become sister moons of your gas giant parent.
If your primary body is an M-class star, triple the length of your day due to tidal forces. If the result is over 100 hours, your planet is tidally locked to its star. If your primary is a K-class star and the length of your planet's day is greater than 150 hours, your planet is also tidally locked to its star. If your primary is a G-class star, and your planet's day is greater than 190 hours, your planet is tidally locked to its star.
Random events
| Roll | Event |
| 1-3 | Global cooling - The global average temperature decreases by 1d4, due to environmental feedback loops, an increase in albedo, a decrease in solar output, or some other factor. |
| 4-6 | Global warming - The global average temperature increases by 1d4, due to environmental feedback loops, volcanic outgassing, an increase in solar output, or some other factor. |
| 7-9 | Climate stabilizes - If the global average temperature is greater than 15 degrees, decrease it by 1d4 degrees. If the global average temperature is less than 15 degrees, increase it by 1d4 degrees. If decreasing the global temperature would lower it below 15 degrees, or raise it above 15 degrees, it remains at 15 degrees instead. |
| 10 | Massive bolide impact - An enormous asteroid strikes the planet, causing a mass extinction event. Roll 1d6 for every species. On a 1-3, they go extinct. On a 4, they survive unscathed. On a 5, the original goes extinct, but a surviving offshoot gains a random adaptation. On a 6, two surviving offshoots are created instead of just one. Due to geological aftershocks, Alter geology actions can alter up to 3,000 px square this round. |
| 11 | Supervolcano eruption - Choose a sub-continental hotspot (or, if none exists, create one). This hotspot triggers a massive, explosive eruption that fills the upper atmosphere with soot, and decreases global temperatures by 2 C. Every player gets an additional, free Targeted extinction action this round. |
| 12 | Evolutionary explosion - Due to environmental factors not visible in the fossil record, meddling by traveling hyper-advanced aliens, or some other unknown factor, this era is an especially fruitful one for biological innovation. Every player gets an additional, free Apply adaptation action, and you may target species that were evolved in this round. |
| 13 | Rare adaptation - An incredibly rare or improbable trait evolves in one species. Apply a random trait from the Rare trait table to a species of your choosing. |
| 14 | Large igneous province forms - Choose a divergent plate boundary or hotspot, or, if no suitable location exists, create a hotspot. For the next 1d4 rounds, global temperature increases by 2 C per round. While the large igneous province is forming, alter geology actions can alter up to 3,000 px square. If the large igneous province takes more than two roudns to form, then on the third round, a mass extinction event occurs: roll 1d6 for every species. On a 1-3, they go extinct. On a 4, they survive unscathed. On a 5, the original goes extinct, but a surviving offshoot gains a random adaptation. On a 6, two surviving offshoots are created instead of just one. |
| 15 | Panspermia - An asteroid carrying an extremely hardy extraterrestrial lifeform crashes into the planet; against all odds, it has survived both travel through space for an unknown length of time, and the impact. A single-celled organism with the adaptations autotrophic, radiophilic, psychrophilic, endospore-forming, facultative anaerobe, and two other random adaptations appears. This event can only occur once. If rolled again, re-roll. |
| 16 | Alien visitation - Alien explorers visit the
planet for inscrutable reasons. Roll a 1d6 to determine which of
the following activities they undertake:
|
| 17 | Bizarre geology - Some incredibly improbable
confluence of factors (or possibly outside intervention) has led
to a bizarre geological formation on your world. Roll a 1d6 to
determine what kind:
|
| 18 | Bizarre skies - Some incredibly improbable
confluence of factors (or possibly outside intervention) has led
to a bizarre meteorological or celestial phenomenon on your world.
Roll a 1d6 to determine what kind:
|
| 19 | Make something up, or pick any outcome off this table. |
| 20 | Roll twice on this table. |
Adaptations
If an adaptation has variations listed, a variation must be chosen when the adaptation is chosen (multiple variations can co-exist). If an adaptation lists variations including "something else," those are merely suggestions to get you started. Adaptations marked with an asterisk are irreversible. Adaptations marked with a + sign stack.
Note that a few traits are automatically present by simple exclusion; any species doesn't have sexual reproduction has asexual reproduction by default; any species that doesn't have autotroph automatically has heterotroph; and any species without some kind of aerobic adaptation is automatically an anaerobe.
If you want to explore niches that remain unfilled in terrestrial biology, might I suggest this paper on so-called 'forbidden phenotypes'?
Basic unicellular adaptations
Use this list of adaptations to choose a random adaptation.- Biofilm
- Bioluminesence
- Cell-to-cell signaling
- Cell wall
- Conjugation
- Crystalline deposits
- Electrosensitivity
- Endomembranes
- Endospores
- Extremophile (has variations thermophile, halophile, acidophile, psychrophile, zerophile, alkaliphile)
- Eyespots
- Flagella/cillia
- Magnetosensitivity
- Meiosis
- Phagocytosis
- Pseudopods
- Symbiosis (has variations mutualism, commensalism, parasitism)
- Syngamy (requires meiosis or conjugation)
- Stromatolites (requires biofilm)
- Taxis (e.g., chemotaxis, phototaxis, magnetotaxis, thermotaxis, barotaxis, gravitaxis, or something else).
- Toxin production
- Trichocysts
- Unusual shape (e.g., rod, pillow, corkscrew, lozenge, cube, flat, lumpy, or something else)
Advanced unicellular adaptations
- Autotroph (fixes carbon as part of energy production; has variations chemoautotroph (requires volcanic activity), lithotroph, electrotroph, phototroph (requires sunlight), diazotroph. Autotroph always replaces heterotroph. A species can only have one kind of autotroph)
- Heterotroph (cannot fix carbon, replaces autotroph)
- Alternate reproduction (has variations budding, fragmentation)
- Aerobe (replaces anaerobe, has variations aerotolerant (can survive in an aerobic environment), facultative aerobe (has both aerobic and anaerobic ways of producing energy) and obligate aerobe (cannot survive without oxygen). A species can have only one kind of aerobe. Requires the Oxygen Catastrophe counter to be at least 20.)
- Endosymbiosis (allows clades diverging from this one to take an additional kind of autotroph adaptation, or heterotroph alongside one kind of autotroph) (requires endomembranes)
- *Variable DNA expression (requires cell-to-cell signalling or biofilm)
- *DNA methylation (requires variable gene expression)
- Endoplasmic reticulum (allows intracellular transport of various molecules; requires endomembranes)
- *Nucleus (requires endomembranes)
- *Multiple nuclei (requires nucleus)
- Cellular specialization (requires variable gene expression)
- Temporary colonies (this unicellular organism comes together in a colonial formation for certain specialized functions, like reproduction, migration, or surviving hostile conditions; requires cellular specialization)
- *Alternation of generations (unicellular) (this organism alternates between different forms with each generation; this may be between a diploid, asexual generation and a halpoid, sexual generation; between colonial and solitary generations; or some other kind of alternation)
- Metamorphosis (this organism has multiple distinct stages in its life cycle, with a physical metamorphosis between them; requires variable gene expression)
- Clonal colonies (this organism forms permanent colonial units made up of individual zooids for all or most of its life cycle; each zooid is a clone of an original “parent” zooid; requires cellular specialization)
- Syncretic colonies (this organism forms permanent colonial units made up of individual zooids for all or most of its life cycle; multiple individuals must join together to found a colony; requires syngamy, metamorphosis, or temporary colonialism)
- Macroscopic unicellular organism (requires multiple nuclei, endoplasmic reticulum)
- *Macro-organelles (this organism is a single large cell with many nuclei; nonetheless, it is capable of specializing parts of itself to accomplish particular tasks, akin to the distinct tissues of a multicellular organism; requires macroscopic unicellular organism, variable gene expression)
- *Multicellular organism (this organism is a true multicellular organism, with each cell taking over specialized functions; requires one of syncretic colonies or clonal colonies)
Once a species is evolved with the multicellular or macro-organelles adaptations, it is considered a multicellular or macroscopic species (even if it's technically unicellular). All unicellular traits are fixed, and can't be removed or changed--they are part of the new species' basic metabolism. Multicellular organisms evolved from a unicellular line with syngamy or meiosis may start with sexual reproduction. Extremophiles and autotrophs retain their specific variety of extremophile and autotroph.
Basic multicellular adaptations
Multicellular adaptations are suitable for any kind of organism--plant, animal, fungus, etc. Adaptations can be interpreted widely, and applied to creatures of any niche, unless noted otherwise. You are not restricted to evolving species which resemble terrestrial ones.
- Pronounced coloration (choose a color/pattern!)
- Reduplication of body part (choose a part!)
- Overdevelopment of body part (choose a part!)
- Underdevelopment of body part (choose a part!)
- Herbivore
- Carnivore
- Detrivore
- Saprovore
- Electroreception
- Magnetoreception
- Color-changing
- Shape-changing
- +Long-lived
- +Short-lived
- +Increase in size
- +Decrease in size
- Biologically immortal
- Burrowing
- Aerostat
- Hydrostat
- Bioluminescent
- Cave-dwelling
- Rock-breaking
- Semelparous
- Mimicry
- Camouflage
- Metamorphosis
- Pupa or coccoon
- Alternation of generations
- Colonial
- Spikes, spines, thorns, or horns
- Urticating hairs or ability to shoot spines
- Extremophile (has variations thermophile, halophile, acidophile, psychrophile, radiophile, zerophile, alkaliphile)
- Hair, fur, or fuzz
- Armor or shell
- Thick hide or bark
- Spotted
- Striped
- Produces silk or fiber
- Produces slime
- Produces corrosive fluid
- Seasonal life-cycle
- Flattened body shape
- Branching body shape
- Weird fronds
- Photoreceptors
- Filter feeding
- Wings
- Permanently airborne (requires wings or aerostat)
- Ultra-subterranean (requires burrowing or cave-dwelling)
- Rough or bumpy exterior
- Migration
- Pyrophyte
- Neoteny
- Regeneration
- Detachable body parts
- Suckers
- Stinger or barbed tail
- Precocial
- Altricial
- Sail
- Scales
- Siphon
- Eyestalks (requires some kind of eye)
- Strange mouth shape (requires gut)
- Unusual orifice
- Unusual sense (requires nerve cluster)
- Reef, dike, or mound-formation
Advanced multicellular adaptations
- Asexual reproduction (has variations budding, fission, sporogenesis, fragmentation)
- Sexual reproduction (has variations free-floating gametes, internal fertilization, external fertilization)
- Sex determination (this organism is no longer composed (solely) of hermaphrodites; you can choose XY, ZW, haploid/diploid, or some other principle on which to base sex determination; requires sexual reproduction)
- Egg-laying
- *Musculature
- *Endoskeleton
- *Exoskeleton
- *Fibrous support structure
- *Nerve cluster
- Symbiosis (has variations mutualism, commensalism, parasitism)
- Mycelium (this organism's main body is a mass of fibrous tissue rather than a single compact body or stem)
- Temporary fruiting bodies (this organism developes a temporary fruiting body to help disperse its spores, seeds, or gametes; it may be much more conspicuous than the rest of the organism)
- Passive vascular system (this organism has ways of transporting nutrients and water through its body passively, via tissues that resemble xylem and phloem)
- Root system
- Leaves (this organism has distinct flattened tissues to aid in gas exchange, photosynthesis, or some other crucial metabolic function)
- Woody tissue (this organism has developed some kind of rigid support structure that allows it to grow to great heights; requires fibrous support structure, mycelium, or passive vascular system)
- Seeds
- Taproot (requires root system)
- Flowers (requires seeds)
- Fruit (this organism uses attractive fruits to lure mobile creatures to distribute its seeds more widely; requires seeds)
- *+Symmetry (choose degree of symmetry: bilateral, 3-fold radial, 4-fold radial, etc.)
- Streamlined body (requires symmetry)
- *Segmentation (this organism’s body is built up out of repeated segments; they may fuse to form special appendages like the head or tail, but the segment is the basic unit of the body plan)
- Eyespots (requires photoreceptors)
- Cup eyes (requires eyespots)
- Enclosed eyes (requires cup eye, small brain)
- Lensed eye (requires enclosed eyes)
- Compound eye (requires eyespots, nerve cluster)
- *Small brain (e.g., the handful of neurons of an insect; requires nerve cluster)
- Eusocial (requires sexual reproduction, small brain)
- Parthenogenesis (at least one sex can sometimes reproduce in the absence of a mate; requires sex determination)
- Sexual selection (requires sexual reproduction, small brain)
- *Gut
- *Digestive tract (requires gut)
- Fins (requires musculature)
- Legs (requires musculature)
- Wings (requires musculature)
- Olfactory receptors (requires nerve cluster)
- *Active circulatory system (has variations open, single-circuit, double-circuit)
- Unusual sense (requires nerve cluster)
- Gills (requires circulatory system)
- Lungs (requires double-circuit circulatory system)
- Peripheral nervous centers (like an octopus; requires small brain)
- Nesting (requires small brain)
- *Thermoregulation (requires double-circuit circulatory system)
- Teeth (requires digestive tract)
- Ears (requires nerve cluster)
- Beak (requires digestive tract)
- Claws (requires endoskeleton or exoskeleton and fins, legs, or wings)
- Hooves (requires legs)
- Tongue (requires digestive tract)
- Predation (requires small brain)
- *Large brain (requires small brain)
Adaptations requiring Large brain
All adaptations past this point require Large brain.
- Short-term planning
- Parental care
- Sleep
- Memory
- Echolocation (requires ears)
- Live birth (requires egg-laying)
- Lactation (requires live birth)
- Ambush hunter (requires predation, short-term planning)
- Sociality (requires memory, short-term planning)
- Swarms or herds (requires sociality)
- Pack hunter (requires sociality, predation)
- Conspecific signalling (whether vocalization, color-changing, or some other manner of elementary communication; requires sociality)
- Dreams (requires sleep, memory)
- Dominance displays (requires short-term planning, sexual reproduction)
- Pattern recognition (requires memory)
- Grasping and object manipulation (requires short-term planning and a usable appendage)
- Emotions (requires pattern recognition)
- Reciprocity (requires emotions)
- Ad-hoc tool use (requires grasping and object manipulation)
- Long-term planning (requires pattern recognition)
- Hierarchy (requires long-term planning)
- Toolmaking (requires long-term planning, ad-hoc tool use)
- Imagination (requires long-term planning)
- Simple utterances (requires imagination, sociality, reciprocity, conspecific signalling)
- Shared attention (requires simple utterances)
- Cooperative tool use (requires shared attention, toolmaking)
- Self-awareness (requires cooperative tool use, simple utterances)
Optional rule: The fate of a self-aware species
If you continue the game past the development of a sentient species, you may at the start of the next round optionally roll for the fate of the civilization during the geologically brief period immediately after it achieves sentience instead. Roll a 1d6, with the following results:
- Rapid growth followed by extinction. One player describes the nature of the civilization, one player describes its downfall, and one player describes the nature of the megastructure(s) or the artifact(s) they leave behind.
- Growth, followed by decline and stasis; this civilization retreats into enclaves or virtual worlds where it lives as a shadow of its former self. One player describes the nature of the original civilization, one player describes the nature of the remnant, and one player describes any megastructure(s) or artifact(s) they leave behind for later species to discover.
- Transcendence. This civilization eventually entirely departs its original homeworld, either because they have built or xenoformed other artificial habitats more to their liking, or they no longer have a need for it. One player describes the nature of the civilization, one player describes its departure, and one player describes the nature of the megastructure(s) or the artifact(s) they leave behind.
- Decline into pre-sapience. This civilization eventually collapses, and while a remnant of its people survive, they regress from sentience. The species loses all traits past toolmaking. One player describes the nature of the civilization, one player describes its downfall, and one player describes the nature of the megastructure(s) or the artifact(s) they leave behind.
- Slow growth. Although this species is sentient, its initial population growth and/or technological development is slow. It remains in a pre-agricultural state, rather than pursuing the arts of civilization.
- Early extinction. This species may have achieved great things, but unfortunately catastrophe struck while it was still young. Disease or disaster wiped it out before it had the tools to protect itself, and it went extinct. One player describes the nature of the civilization that formed, if any, and another describes the extinction that followed.
On a 1-4, a mass extinction event also occurs due to the disruption of the environment as the civilization matures: roll 1d6 for every species. On a 1-3, they go extinct. On a 4, they survive unscathed. On a 5, the original goes extinct, but a surviving offshoot gains a random adaptation. On a 6, two surviving offshoots are created instead of just one.
Rare adaptations
Rare adaptations are normally unavailable, unless you roll the "rare adaptation" event as a random event. Roll a 1d20 to select a rare adaptation from this list:
- Collective cognition - individual organisms of this species are autonomous, but their cognition or consciousness exists in the collective. Via chemical, electromagnetic, or other means, individuals engage in complex signaling with one another; this cognition doesn't necessarily rely on nervous tissue as it's commonly understood. This adaptation cannot be inherited by a daughter species.
- Magma-swimmer - this organism's metabolism is so specialized, and its cellular structure so unusual, it can move through molten rock with ease.
- Genetic memory - this organism imprints important memories or somatic adaptations within the non-coding portions of its DNA, so that its experiences can be passed on to descendants.
- Contact telepathy - this organism has adapted a complex chemical or eletromagnetic mechanism that is capable of altering or overriding the nervous system of creatures that come into physical contact with it.
- Gargantuan size - this organism can grow to seemingly impossible sizes: hundreds, or even thousands of feet, in at least one dimension, large enough to be mistaken for part of the landscape from a distance. This adaptation cannot be inherited by a daughter species.
- Extremely rare - this organism has traded a fundamental genetic imperative--spreading its genes as far as possible--for some kind of extreme hardiness. Whether as part of its alternation of generations, or a constant property of its population, it at least occasionally dwindles down to extremely few numbers--perhaps as small as the single digits. This adaptation cannot be inherited by a daughter species. Species with this adaptation cannot go extinct.
- Firebreathing - this organism can spit a mixture of volatile chemicals that instantly bursts into flame on contact with air.
- Psychic vampirism - a fundamental part of this organism's nutrition, reproduction, and/or growth requires preying on species with advanced neurology by telepathic means. This trait requires at least one other species with Small brain to exist; if none does, re-roll. If no species with Small brain remains, species with this trait will go extinct.
- Ultra-high-altitude flight - this species can travel high into the atmosphere--into the thermosphere, the exosphere, or even into a low orbit for a short time. One day it might even become naturally space-faring, if it can find a way to propel itself from planet to planet and star to star.
- Immortal consciousness - even if the individual dies, its mind can survive. Perhaps it exists within the collective unconscious until it is reincarnated; perhaps it leaves behind a crystalline essence that descendants can eat to remember its experiences; perhaps it exploits as-yet-untapped mechanisms of physics to do so. Requires small brain; otherwise, re-roll.
- Mr. Potato Species - due to a genetic bottleneck, a freakish kind of autotomy, and effective regeneration mechanisms, this species can literally swap body parts from one member to another, like overcharged plant grafting that occurs naturally.
- Omnisexual - this species is capable of a unique kind of asexual reproduction that epigenetically imprints offspring with traits of an otherwise totally incompatible mate. The result is not a true hybrid, as these imprinted traits are not heritable, but it does allow this species to adapt efficiently to new environments. Requires sexual reproduction in some form; otherwise, re-roll.
- Precognition - either this species is so efficient at processing sensory information, or it can somehow override basic laws of physics, to allow it to see seconds or milliseconds into the future--a small but incredibly powerful advantage over the competition. Requires small brain; otherwise, re-roll.
- Internal transmutation - this organism has at least one metabolic pathway that utilizes a protein complex with a specialized site that can exploit quantum-mechanical phenomenon to directly transmute elements, giving it access to some truly improbable chemical processes.
- Viral agent - this organism has developed a symbiosis with an extremely deadly viral agent which lives in its tissues, and causes fulminant tumors and necrosis in organisms that try to eat its flesh and/or that come too near. Requires a multicellular species; otherwise, re-roll.
- Genetic stasis - an unfortunate failure of this creatures genome has produced an organism for whom almost all significant mutations are deadly. New daughter species cannot be created from this species under any circumstances.
- Petrification - this organism can deliver a prion into the body of other organisms that causes a rapid conversion of normal tissue into a hard, dead, stony substance.
- Organ scavenging - this organism can scavenge organelles (if microscopic) or organs (if macroscopic) from other species and incorporate them into its body, while retaining much of their function. Perhaps it can only do so with certain specialized organs, or perhaps it can do this with almost any kind of tissue.
- Wheels - fairly self-explanatory!
- Diaphanous form - all or part of this organism's body is not composed of truly solid substance--it is a liquid or gaslike form held together by electric charge or some more unusual physical force.