The Alien Classification List, also known as the ACL, is an article describing the different classifications of various lifeforms for research and sorting purposes as used on Earth-83.
The various types of lifeforms described on the list are each assigned "Classes", which designate their overall composition. Certain species may belong to more than one class.
Flora are organic lifeforms that can be considered plants and/or fungi. Though most Flora is not considered to be thinking or sentient in any way, certain species, such as Florauna or Methanosians, can be classified as such.
Automata are inorganic, mechanical/nanomechanical lifeforms. Most species that fall under this class are artificially made, though naturally-occuring Automata are not entirely unheard of. This class includes species such as Chronosapiens and Galvanic Mechamorphs.
Aqua are lifeforms whose bodies are made primarily of liquid. Though most Flora and Fauna species have quite a lot of liquid in their makeup, Aqua species are almost exclusively composed of it, giving them a generally amorphous body. This class includes species such as Lenopans and Polymorphs.
Vitalis species, generally known as "energy beings", are lifeforms primarily composed of energy of some sort, such as electricity or mana. This class includes species such as Nosedeenians and Anodites.
Spiritual species are lifeforms with a more otherworldly makeup than other classes. This class includes species such as Ectonurites.
Undefined species have makeups so rare and unique that creating a separate classification for them would be practically useless. This class includes species such as Thep Khufans, whose bodies are made up of organic bandages, and Sonorosians, whose bodies are living sound waves wrapped in silicon containment suits.