Taxonomy Physical / Metaphysical Law in A To Zoo | World Anvil


Taxonomy is the study of naming and classifying organisms into groups based on shared characteristics. The current taxonomy used was taken completely from human culture from the planet Earth. Many of the most important scientific communities in the Yonderverse use the Earth-based taxonomy system, as it is one of the most detailed yet easy to understand classifications out there.

Classifying Organisms

Organisms are typically classified based on physical characteristics. There are a handful of well-known classes of animals, including but not limited to Mammalia, Aves, and Insecta. Typically, these classes will have one or several main characteristics, such as mammals all possessing mammary glands, birds all possessing feathers and laying hard-shelled eggs, and insects possessing three body parts and three pairs of legs.

If an animal brought to our zoo is not currently classified in the Earth-based classification system, we take responsibility and find a place for it. On rare occasions we have to design a completely new genus, family, or rarely order or class for the animal, but most of the time the species will fit somewhere thanks to how detailed the classification system already is.

Earth & Alien Organisms

No Earth organism goes without a place in the classification system, since it was designed for them. All animals are related to each other in some way on Earth, as that's how evolution works. Unfortunately it becomes more difficult to classify alien creatures in the Earth-based system, since they are not related in any way. Instead, we usually compare physical and behavioural characteristics to Earth creatures. This is also why so many animals not from Earth have English and Latin names, as English and Latin are common languages seen in the scientific community.


Taxonomic Ranks

Different planets may be home to organisms that defy all of these ranks. These are generalised ranks that apply to most organisms in the Yonderverse, and can be seen on most planets.


Domain is the highest taxonomic rank in the taxonomy system. There are three domains : Eukarya, Bacteria and Archaea.


These organisms are made of cells containing nuclei. Every animal you see in the zoo falls under this domain. This is smallest of the domains.


These organisms lack nuclei in their cells and are often single-celled organisms. Bacteria are almost always the first organisms to arise on planets.


These organisms are all single-celled. Archaea may be similar to both eukaryotes and bacteria, but few differences have resulted in their unique domain.


Kingdom is the second highest taxonomic rank in the taxonomy system. There are several kingdoms, some viewed in some places and some are not, but in the zoo we recognise five: Animalia, Plantae, Fungi, Protista, and Monera.


Animalia are all multicellular, eukaryotic organisms. Most have the ability to move, breathe, and consume organic material.


Fungi are all multicellular, eukaryotic organisms. They are characterised by the chitin in their cell walls.


Plantae are all multicellular, eukaryotic organisms. Most are stationary, contain some amount of chlorophyll.


Protista are all eukaryotic organisms that is not a fungi, plant or animal. Because of this, protista is a very diverse kingdom.


Monera are all prokaryotic organisms that lack nuclei. Monera consists of the entirety of the Bacteria and Archaea domains.


Phylum is the third highest taxonomic rank in the taxonomy system. There are countless phylums, however only a few are important to the zoo.


All animals under chordata possess, or have possessed at some point in their growth stage, five synapomorphies. These five synapomorphies include a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal slits, and a post-anal tail.


Arthropods are invertebrate animals with an exoskeleton, paired jointed appendages, and segmented bodies.


Cnidarians are mostly invertebrate animals. They are the only phylum to possess cnidocytes, designed to capture prey.


Echinoderms are an entirely marine phylum. Most are radially symmetrical, such as sea stars and sea lilies.


One of the largest classes. Incredibly diverse, but all possessing a mantle and a nervous system.


Class is the fourth highest taxonomic rank in the taxonomy system. There are countless classes, and these are the most common taxonomic rank that unique animals will fall into. Such examples is aurvada, a class of animals found exclusively on Jupiter.

Some common classes with animals found across the Yonderverse include:

  • Arachnida (Spiders, scorpions etc.)
  • Malacostraca (Crabs, lobsters etc.)
  • Insecta (Insects)
  • Chilopoda (Centipedes)

  • Mammalia (Mammals)
  • Aves (Birds)
  • Reptilia (Reptiles)
  • Chondrichthyes (Cartilaginous fish)

  • This is not a definitive list of all of the classes. These are the eight most common classes found across the Yonderverse, and there are thousands more.


    Order is the fourth smallest taxonomic rank in the taxonomy system. Order is the first rank where taxonomists disagree with each other. There are almost twenty times as many orders as there are classes, because new ones are constantly invented to fit newly discovered creatures.

    Here at A to Zoo, we believe we have created the most appropriate order for every creature in our collection, about 33% of every known animal in the Yonderverse. Every time we obtain a new species, we have our specialised taxonomist team to assign them an order. We have a publish document displaying our taxonomy tree, which is used across the Yonderverse. We are very proud to say it was designed completely by us, and that so many people use it.


    Family is the third smallest taxonomic rank in the taxonomy system. Once again, taxonomists often disagree with each other on families. Once again, we have created a rich database with every single species in what we believe to be the appropriate family.

    Here are some examples of families of Earth animals:

    Mammalian Families

    Order: Primates
  • Lemuridae (Lemurs)
  • Cebidae (New World Monkeys)
  • Cercopithecidae (Old World Monkeys)
  • Hominidae (Great Apes)
  • Order: Carnivora
  • Felidae (Cats)
  • Canidae (Dogs)
  • Ursidae (Bears)
  • Phocidae (True Seals)
  • Order: Whippomorpha
  • Hippopotamidae (Hippos)
  • Balaenidae (Bowhead Whales)
  • Balaenopteridae (Grey Whales)
  • Delphinidae (Dolphins)
  • Avian Families

    Order: Galliformes
  • Megapodidae (Megapodes)
  • Numididae (Guineafowl)
  • Phasianidae (Pheasants)
  • Cracidae (Curassows, Chachalacas & Guans)
  • Order: Psittaciformes
  • Strigopidae (Kakapo)
  • Cacatuidae (Cockatoos & Cockatiels)
  • Psittacidae (African & American Parrots)
  • Psittaculidae (Australasian Parrots)
  • Order: Passeriformes
  • Meliphagidae (Honeyeaters)
  • Corvidae (Crows, Jays, Ravens etc.)
  • Troglodytidae (Wrens)
  • Genus

    Genus is the second smallest taxonomic rank in the taxonomy system. Another rank where taxonomists can disagree on, it is uncommon two find two animals from different planets in the same genus as the chances of animals so similar to each other that they fall under the same genus are extremely low. That being said, it is seen often but compared to how many species there are in the Yonderverse, it is only a small percentage. Usually, animals of the same genus are related to each other and have a common ancestor.

    An animal's binomial, or scientific, name partly relies on their genus. For example, the golden fox's scientific name is vulpes aurum. The golden fox is a species within the genus Vulpes, along with many other fox species.


    Species the most basic taxonomic rank in the taxonomy system, and the one people are most familiar with. Each species is given a binomial name that consists of two words - the genus comes first, and the latter word distinguishes the species. For example, vulpes aurum and vulpex pictor are both species of fox under the Vulpes genus, but are two completely different species - the former being the golden fox from Laosina, and the latter being the painter fox from Greenerth.

    Below is an example of how an organism would be classified. This animal is a golden fox, and is a species of true fox as it exhibits many physical and behavioural characteristics of others in its genus, Vulpes.
    Scientific Classification
    Kingdom: Animalia
    Phylum: Chordata
    Class: Mammalia
    Order: Carnivora
    Family: Canidae
    Genus: Vulpes
    Species: V. Aurum

    Unique Classes

    On rare occasions there are classes of animals endemic to a single planet. One of the best examples is Jupiter, a planet in the Kinosmo System of District 2. This planet is home to aurvads, a common name for animals in the Aurvada class.

    These animals are characterised by chitin scales, a proboscis, and laying soft-shelled eggs. There are five-hundred thousand aurvads on the planet, and 96% of them can be found in the zoo.

    Jovian Ray by Mochi


    Please Login in order to comment!
    Feb 28, 2023 18:18 by Dr Emily Vair-Turnbull

    Great summary! <3

    Emy x   Etrea | Vazdimet
    Feb 28, 2023 19:10 by Mochi

    Thank you! :D

    I hope you have a great day!   Explore the endless planets brimming with life of the Yonderverse! Go after creatures, discover new places, and learn about the people you find along the way.   Check out my new world, Ava Admira!
    Feb 28, 2023 21:55 by Ademal

    Bravo for tackling this, taxonomy makes my head spin!

    Check out my summercamp by going here and checking out any of my gold-star articles!

    Feb 28, 2023 22:15 by Mochi

    Thank you so much! It is an absolute nightmare, and worse when people don't always agree on it xD

    I hope you have a great day!   Explore the endless planets brimming with life of the Yonderverse! Go after creatures, discover new places, and learn about the people you find along the way.   Check out my new world, Ava Admira!
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