Chapter 18

1. Chapter 18 Classification

2. Section 18-1: History of Taxonomy • Taxonomy is the branch of biology that names and groups organisms according to their characteristics and evolutionary history. • The first classification system was set up by Greek philosopher Aristotle, he classified organisms as plants or animals.

3. Section 18-1: History of Taxonomy • Swedish naturalist, Carolus Linnaeus came up with the next famous system of classification. • He used an organisms morphology, structure and function, to place it in the system.

4. Section 18-1: History of Taxonomy • The Linnean system is a nested hierarchy of seven different levels: • KINGDOM • PHYLUM • CLASS • ORDER • FAMILY • GENUS • SPECIES

5. Section 18-1: History of Taxonomy • The names of organisms in Linnean classification are made up of two parts (binomial nomeclature). • The first part is the genus and the second part is the species identifier, usually a descriptive term.

6. Section 18-1: History of Taxonomy • Some organisms are very similar and may only be separated by region or by one characteristic. • In plants similar organisms with very small variations are known as varieties. • EXAMPLE: Peaches and Nectarines are varieties of, Prunus persica (Peach tree)

7. Section 18-1: History of Taxonomy • Variations among animals are referred to as subspecies. • EXAMPLE: Brown bears and grizzly bears are subspecies of the brown bear, the difference is the size of the bear and the region in which it is located.

8. Section 18-1: History of Taxonomy • Modern classification of organisms is done by phylogeny which is evolutionary history.