All courses › Biology 1 › Taxonomy

Taxonomy

To keep track of relationships, life is sorted into levels, from large groups down to the single species. The order is kingdom, phylum, class, order, family, genus and species. That is seven levels. Two species in the same genus are more closely related than two species that only share a kingdom. The scientific name is genus plus species, as in Homo sapiens. The genus is written with a capital letter, the species with a small one. The system lets biologists in different countries talk about the same organism even when the everyday name differs.

\text{kingdom} \rightarrow \text{species}

seven levels, from large to small

Symbols

$genus$	first part of the scientific name
$species$	second part

Example

Kingdom, phylum, class, order, family, genus and species.

That is 7 levels. Homo is the genus, sapiens the species.

Viruses are not in the three domains. They do not have cells of their own.

Practise biodiversity and classification for free →

← With and without oxygen · How many species →

Part of Biology 1: Biodiversity and classification.