1. History of Classification

2. New organisms are still being found and identified
Species of organisms
According to livescience.com, there is approx. 1 trillion species of organisms
New organisms are still being found and identified

3. Aristotle divided organisms into plants & animals
Early Taxonomists
Aristotle is given credit for developing the first widely accepted system of biological classification
Aristotle divided organisms into plants & animals
Plants he classified into 3 groups, herbs, shrubs, and trees depending on the size and structure
Animals were classified according to various characteristics including habitat and physical differences
Aristotle’s system was not based on evolutionary history of animals

4. Carolus Linnaeus 1707 – 1778

5. 18th century taxonomist
Called the “Father of Taxonomy”
Linnaeus’s system was based on physical and structural similarities of organisms; as a result, the groupings revealed the relationships of the organisms

6. Developed naming system still used today known as binomial nomenclature
Binomial nomenclature is the 2-word naming system that is written in Latin
Genus, which is the first word, is the group the animal belongs in (always capitalized)
Specific epithet, second word, describes a characteristic of the organism (never capitalized)
Binomial nomenclature made communication about certain species much easier

8. Binomial Nomenclature

10. Dichotomous Key
Sometimes just having a little bit of information can help identify organisms, but it doesn’t always help you get to the answer that you want to get to
Taxonomists have developed a tool called a dichotomous key to help identify organisms when there is only a little bit of information provided
A dichotomous key asks a series of questions that can be answered in only 2 ways; the questions gradually help to narrow down the list of possible organisms

11. Example of Dichotomous Key
1a Tentacles present – Go to 2
1b Tentacles absent – Go to 3
2a Eight Tentacles – Octopus
2b More than 8 tentacles – 3
3a Tentacles hang down – go to 4
3b Tentacles upright–Sea Anemone
4a Balloon-shaped body–Jellyfish
4b Body NOT balloon-shaped - 5