1. Classifying the Diversity of Living Organisms1

2. What is classification?
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 2

3. Classifying Species
All organisms are slotted into eight nested levels of taxonomic categories known as ranks
Domain
Kingdom
Phylum
Class
Order
Family
Genus
species

4. Sample Classification of a Panther

5. Kingdom Phylum/Division Class Order Family Genus Species
Human
Box Elder Tree
Bobcat
Canadian lynx
Kingdom
Animalia
Plantea
Phylum/Division
Chordata
Anthophyta
Class
Mammalian
Dicotyledonae
Mammalia
Order
Primates
Sapindales
Carnivora
Family
Hominidae
Aceracae
Felidae
Genus
Homo
Acer
Lynx
Species
sapiens
nugundo
rufus
canadensis 5

6. What is a Domain?
A domain is the highest level of taxonomic classification
The three domains are Bacteria, Archaea, and Eukarya
Bacteria and Archaea are also names of kingdoms
The domain Eukarya contains the other 4 kingdoms of Protista, Fungi, Plantae and Animalia

7. The 6 Kingdoms
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 Eubacteria
Protista
Fungi
Plantae
Animalia 7

8. Binomial Nomenclature
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. 8

9. What is a scientific name?
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 sapiens
The 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 9

10. Dichotomous Key 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. 10

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