How is life on earth organized?

1 Answer
Feb 23, 2018

Assuming you are referring to taxonomy: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.


Taxonomy, the study of organizing life on Earth, classifies organisms by their similar traits. The broadest category, the Domains, can each contain millions of species. There are 3: Archea, Bacteria, and Eukarya.

Archea is made up of prokaryotic (a more primitive type of cell) cells without nuclei, that are extremophiles, or organisms that survive in extreme environments like volcanic vents, or under sheets of ice.

Bacteria is also made up of prokaryotic cells without nuclei, only more conventional/common forms.

Eukarya, however, is made up of eukaryotic (more modern) cells, which have nuclei. This includes multicellular organisms (organisms with more than one cell) and unicellular organisms (organisms that are only one cell).

The second-broadest category is Kingdom. For example, in Eukarya, there are four kingdoms: Protista, Fungi, Plantae, and Animalia, which contain protists, fungi, plants, and animal respectively.

Each kingdom is further divided into phyla (singular: phylum), which are divided into classes, which are divided into orders, which are divided into families, which are divided into genera (singular: genus), which are divided into single species.

A species name is the name of its genus, followed by the name of its individual species.

An example: the domestic cat. This example includes why it is in a particular category, as well as the names of said categories.

Domain - Eukarya (It is made of more than one eukaryotic cell)
Kingdom - Animalia (It is an animal)
Phylum - Chordata (It has a backbone)
Class - Mammalia (It is a mammal)
Order - Carnivora (It is a carnivore [eats only meat])
Family - Felidae (It is a type of feline)
Genus - Felis (It is a small feline)
Species - Catus

The scientific name of the domestic cat is Felis catus.