1. Classification Essential Question
Why is it important to place living things into categories?

2. WHY CLASSIFY?
Organization is necessary when dealing with large numbers of something
It’s easier to work if there is a system of how to keep track of things
If you have a specific place for something, then you don’t spend time hunting around trying to find it
There are some million organisms on Earth!

3. History of Taxonomy Objectives
Describe Aristotle’s classification system, and explain why it was replaced.
Explain Linnaeus’s system of classification, and identify the main criterion he used to classify organisms.
What are the seven levels of organization that Linnaeus used to categorize organisms?
What criterion do modern taxonomists use to classify an organism?
What are two reasons that species names are more precise than common names?

4. Early System of Classification
Classification is the grouping of information or objects based on similarities
Taxonomy is the branch of biology that names and groups organisms according to their characteristics and evolutionary history.
Organisms were first classified more than 2,000 years ago by the Greek philosopher Aristotle.

5. Early System of Classification
Organism’s were grouped into land dwellers, water dwellers, and air dwellers.
Plants were placed into three categories based on the differences in their stems.
As new organism’s were discovered, this system became inadequate.
Categories were not specific enough.
Common names did not describe a species accurately.
Names were long and hard to remember.

6. Modern System Based on Hierarchy Carl von Linné (Carolus Linnaeus) 1707 – 1778
Swedish biologist considered the father of modern taxonomy.
Science of Systematics dates to Linnaeus in the 18th century who devised the basic systems of binomial nomenclature and hierarchical classification.
All organisms have a unique binomial name
Humans are Homo sapiens

7. Nested Hierarchy Seven Levels of Organization
Linnaeus used morphology (form and structure), to categorize organisms.
His system is still used today.
He first divided all organisms into two Kingdoms, Plantae (Plants) and Animalia (animals).
This was the same as Aristotle’s main categories.

8. Nested Hierarchy Seven Levels of Organization
Modern System:
Each kingdom (plant and animal) was divided into a phylum* (division for plants)
Each phylum into a smaller groups called class
Each class was divided into an order
Each order was divided into family (families)
Each family was divided into a genus (plural-genera)
Each genus was divided into a species (scientific name)
*Note: Phyla and Family were not in Linnaeus’s classification system but were added by modern scientists.

9. Levels of Classification
King Kingdom
Philip Phylum
Came Class
Over Order
For Family
Grandma’s Genus
Soup Species

10. Hierarchical Classification
Each categorization at any level is called a taxon.

11. Hierarchical Classification
Variations of a species that occur in different geographic areas or habitats are called subspecies.

12. Additional Levels of Organization
Botanist sometimes split species into subsets known as VARIETIES.
Peaches and nectarines are a different variety of the peach tree, Prunus persica
peach

13. Binomial Nominclature
We only know about a fraction of the organisms that exist or have existed on Earth.
Taxonomists give a unique scientific name to each species they know about whether it’s alive today or extinct.
Why not just use common names?

14. Mountain Lion

15. Devil Cat

16. Screaming Cat

17. Puma

18. Ghost Cat

19. Panther

20. Cougar

21. Catamount

22. Binomial Nomenclature
There are at least 50 common names for the animal shown on the previous 8 slides.
Common names vary according to region.
Soooo……why use a scientific name?

23. What’s in a Name? A common name can be used by more than one species
Erithacus rubicula
Robin
Turdus migratorius
Robin
A common name can be used by more than one species
A scientific name must be unique

24. Binomial Nomenclature
The scientific name comes from one of two “dead” languages – Latin or ancient Greek.
Why use a dead language?
Because in the 18th century scientists everywhere understood these languages.
The FIRST word of the Scientific Name is the Genus to which the organism belongs.
The Genus name refers to the relatively small group of organisms that share many similarities
The SECOND word of the name is the species.
The Species name is usually a Latin description of some important characteristic of the organism.

25. Binomial Nomenclature: Rules for Writing Scientific Names
The first letter of the Genus is ALWAYS capitalized
The first letter of the species is NEVER capitalized
Scientific names of organisms are always italicized or underlined
For example:
Red maple tree (common name)
Acer rubrum or Acer rubrum (scientific name)
Acer is the Latin name for Maple (genus)
rubrum is the Latin word for Red (species)
The name can also be abbreviated as: A. rubrum

26. Binomial Nomenclature: Rules for Writing Scientific Names
Humans are named: Homo sapiens
Homo because of our large brain and upright posture.
sapiens because of our intelligence and ability to speak.

27. Classification of Living Things
• Eubacteria: the oldest forms of bacteria.
• Archaea: More advanced forms of bacteria.
• Eukaryota: All life forms with eukaryotic cells including plants and animals