Taxonomy/Classification System

The taxonomic classification system developed by Carolus Linnaeus is used by scientists worldwide. His taxonomic system established a hierarchical structure for classifying organisms based on their physical characteristics, the framework of which is still used today.

The hierarchical structure beings by grouping organisms into a broad category - either Domain or Kingdom. Domains are divided into Kingdoms, which are further divided into Phylum, and they in turn, into Classes. The Classes are narrowed even further into Orders, Families, and Genera. Finally, organisms are grouped by the narrowest of physical attributes into Species. Organisms of the same species all share very specific characteristics.

The Linnaean system uses binomial nomenclature, which means each organism is given a two-part name. The first part of the name identifies the organism's genus and the second part identifies its unique species. For example, humans are called Homo sapiens (Homo = genus and sapiens = species).

Here is how one species of diatom (a type of algae) is classified in the Linnaean system:
There are approximately 100,000 different species of diatoms alive today, and each species shares a specific set of characteristics that distinguishes it from the other diatom species. The scientific name for the diatom in the example in the table above is Asterionella formosa. You will notice that when the scientific name of an organism is written, it is italicized. Also, the genus name is capitalized while the species name is lowercase.