Classification is the grouping of organisms according to characteristics

Taxonomy is the science of classifying organisms based on physical characteristics

Our taxonomic system was developed by Carolus Linneaus in the 1700’s

HumanBox Elder Tree

BobcatCanadian lynx

Kingdom Animalia Plantea Animalia Animalia

Phylum/Division Chordata Anthophyta Chordata Chordata

Class Mammalian Dicotyledonae Mammalia Mammalia

Order Primates Sapindales Carnivora Carnivora

Family Hominidae Aceracae Felidae Felidae

Genus Homo Acer Lynx Lynx

Species sapiens nugundo rufus canadensis

A domain is the highest level of taxonomic classificationThe three domains are Bacteria, Archaea, and EukaryaBacteria and Archaea are also names of kingdomsThe domain Eukarya contains the other 4 kingdoms of Protista, Fungi,

Plantae and Animalia

Classification often skips the domain and starts with the kingdoms shown below:

Archaea – separated from Monera in the 1990’s

Bacteria, also called Monera or EubacteriaProtistaFungiPlantaeAnimalia

The 6 Kingdoms

Each organism has a two part scientific name

The first name is the genus which is always capitalized

The second name is the species which is always lowercase

Names are in Latin because it was the language of scholars.

Each species has a unique scientific name but many organisms have a variety of common names

Scientific names of organisms are always italicized or underlined

For example Homo sapiens or Homo sapiensThe three ways to identify a species focus on

the biological species concept of fertile offspring, the phylogenetic species concept based on evolutionary history and the morphological species concept based on body features

Dichotomy---to divide in two A dichotomous key is commonly used by scientists to classify living organisms. At each step there are two alternatives offered, and the choice of one of those alternatives determines the next step.