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Classification of Organisms
Classification of Organisms

Classification of Organisms

Author: Nathan Lampson

This lesson will introduce taxonomy and give an example by providing the scientific classification of an organism.

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When an organism is discovered on earth it is given a name.  Biologists name organisms with a system that helps to represent how they are related to each other.  First off, there are three domains that all living things are seperated into.  Organisms are classified as either Bacteria, Archaea, or Eukarya.  We are looking at the Grizzly Bear for this example: Grizzly Bears are found in the domain Eukarya because they have complex cells with nuclei.


With a two part scientific name for each organism, biologists give a specific name to identify each organism.  The two part scientific name for an organism is written in italics with the first word beginning with a capital letter and the second word beginning with a lowercase letter.  


The two part binomial name for a grizzly bear is Ursus arctos.


Each organism has a two part name, but they are also part of a hierarchy of classification.  The hierarchy helps to describe how organisms are related to each other.


The seven levels of classifying an organism:


Kingdom (Broadest category of organisms)

The kingdom an organism belongs to is the most broad category.  Multicellular animals are classified in the kingdom Animalia.  Other animals like cats and wolves also belong to the kingdom animalia.



Organisms in the same phylum share some characteristics.  Grizzly bears belong to the phylum chordata because they have a spine.



Getting more specific, Grizzly bears belong to the class Mamalia. The organisms of Mamalia have warm blood and feed their young with milk that they produce.



The order Carnivora describes animals that are meat eating.



Ursidae is the family name for all bear species.



The Ursus genus describes closely related bears including polar bears, black bears, and polar bears.


Species (Most specific category containing only one organism)

Grizzly bears belong to their own species with the species name arctos.