Random Taxonomy Generator

A while ago, for a project long since on perma-hiatus, I made a (partial) generator for plantary biospheres, working on a fractal system from Domains downwards.

Superdomains
Superdomains are not considered in planetary ecosystem generation. Ecosystems will be implicitly divided into acytota (non-cellular life) and cytota (cellular life), with acytota being considered irrelevant.

Acytota appears when a planet reaches a Viral life level, and Cytota appears when a planet reaches a Prokaryotic life level.

The remainder of the ecosystem generation will exclusively cover Cytota.

Domains
The first step is to divide the planetary ecosystem into 1d3 + 1 domains. A domain can be either prokaryotic or eukaryotic. Worlds with a life level of at least Prokaryotic can have a minimum of one prokaryotic domain; worlds with a life level of at least Eukaryotic can have a minimum of one eukaryotic domain. For additional domains, roll a 1d2 to find out which of the two types it is – 1 for prokaryotic and 1 for eukaryotic.

Kingdoms

Each domain is divided up into 1d6 kingdoms, which defines the number of kingdom slots available. Eukaryotic kingdoms can be either monocellular or multicellular. Kingdoms can also either be autotrophic or heterotrophic.

If a kingdom is a heterotroph, then an autotrophic kingdom must also be added to the same domain if none exists.

If the planetary life level is animal or above, throughout the eukaryotic kingdoms there needs to be at least one motile multicellular heterotroph kingdom and one multicellular autotroph kingdom. Assign these to the domains with them most available kingdom slots. If there are no available kingdom slots under the existing eukaryotic domains, add another to the domain with the least kingdom slots.

Once the requirements are fulfilled, additional kingdoms may be described in empty slots. Roll a 1d2 to determine whether a eukaryotic kingdom is multicellular – a 1 is monocellular, and a 2 is multicellular. Prokaryotic kingdoms are always monocellular. Roll an additional 1d2 to determine whether a kingdom is autotrophic or heterotrophic – 1 for autotrophic, and 2 for heterotrophic.

Finally, roll a 1d3 to determine whether the kingdom is typically motile or sessile, and check the following table against whether it is an autotroph or a heterotroph:


Phyla

There are 1d40 phyla within each kingdom.

Phyla can have a different motility to their parent kingdom. Determine this by rolling a 1d10. If the parent kingdom of the phylum is sessile, a roll of 0 means that the phylum itself is motile. If the parent kingdom is motile, a role of 9-0 means that the phylum is sessile. Otherwise, the phylum shares a motility with its parent kingdom.

For multicellular kingdoms, roll a 1d6 to find out the typical form of reproduction of the phylum. Then check against whether the kingdom is motile or sessile.


Phyla with complex sexual reproduction systems will have 1d3+2 sexes.

For multicellular motile kingdoms, first roll a 1d10. A world with a life level of Sapient needs at least one phylum with a central nervous system.

Otherwise, roll on the following table to find the type of intelligence that the phylum has. A sessile phylum will always have a diffuse nervous system.


A diffuse nervous system is one such as that found in sponges where there are no clearly defined control structures at all. A ganglionic nervous system is one such as that found in insects where the nervous system comprises a collection of bundles of nerve cells, called ganglia. A central nervous system is, in this case, on such as that found in vertebrates where there is a single spinal cord and a large brain.

Classes

There are 1d5 classes in each phylum.

Each class of organisms has a typical size, which is randomly selected but modified by many factors pertaining to the parent phylum.

For multicellular organisms, find the size by rolling 1d6 against the complexity of the parent phylum’s nervous system and the motility of the parent phylum according to the following table:


This represents the typical size of organisms in the order: specific orders and below may have larger or smaller sizes.

Monocellular organisms will always be microscopic.

Lifeforms with diffuse nervous systems can be very small indeed, without the need for any bulky structures, so they can be too small to see unaided. Large motile diffuse organisms are very rare, due to being outcompeted with organisms that have, and with their size can afford, more advanced nervous systems.

Ganglionic nervous systems need larger bodies, and due to the nature of ganglions have size limits meaning that they can’t approach any longer than a few feet – no giant insects here.

Central nervous systems need the largest bodies to support energy-intensive brains, but have few size limits beyond those imposed by gravity, the laws of engineering, and the need for motility.

Classes also typically exist in one biome type – either terrestrial or ocean biomes. Roll 1d2; on a roll of 1, the class is typically oceanic, and on a roll of 2, the class is typically terrestrial.

Orders

There are 1d30 orders in each class.

Orders typically exist in one biome. Roll to find the preferred biome of the order, depending on its parent classes’ preferred biome type and the parent planet’s temperature:


To find the typical size of an order, roll a 1d10. On a roll of 1, it is one size class smaller than its parent class. On a roll of 0, it is one size class larger than its parent class. Size classes that would otherwise be below microscopic are microscopic. Size classes that would otherwise be above huge are huge. Otherwise, the order is the same size as its parent class.

Families
There are 1d10 families in each order.

Families typically exist in one environment type. Roll and check the below table against the preferred biome of the class to find the preferred environment of the order if it is a terrestrial order.


If the family is heterotrophic, the typical diet of a family contains three elements: the gatherer/miner axis, the motile/sessile axis, and the dead/live axis.
The gatherer/miner axis is the feeding strategy of the lifeform. Gatherers move around in search of food; miners stay in one place to retrieve food.

The motile/sessile axis determines what type of life the family typically eats. Motile means that members of the family eat motile lifeforms; sessile means that they eat sessile lifeforms.

The dead/live axis determines the life state of the lifeforms the family eats. Dead means that the family eats things that are already dead, such as scavengers and decomposers. Live means that the family eats things that are not already dead, such as with hunters and parasites.

Roll a 1d10, and check against the motility of the parent phylum the following table to find out the family’s position on the gatherer/miner axis. Then, roll another 1d10 check against the feeding strategy of the family to find out whether it eats motile or sessile lifeforms. Finally, roll a 1d10 and check against the feeding strategy to find out whether the family generally eats dead or living lifeforms.

Feeding strategy (roll against mobility):


Diet (roll against feeding strategy):


Life of Diet (roll against feeding strategy):


Genera

There are 1d16 genera in each family.

Species

Roll on this table to find the number of species in each genus:


If the planet has sapient life, select one species that has the following properties:

• Domain is eukaryotic.
• Kingdom is motile, heterotrophic and multicellular.
• Phylum has a central nervous system.
• Class prefers a land biome type.

This is the species that makes up the civilisation of the planet.