1. Chapter 18 Taxonomy- branch of biology that groups & names organisms
Earth is home to millions of different kinds of organisms.
Each of these organisms share some common features with every organism
To help understand and organize information about living things, scientists have created a system for classifying them into groups.

2. The Greek philosopher, Aristotle, developed the first method of classification
He divided everything into 2 groups:
Plants- herbs, shrubs, trees
Animals- aquatic, terrestrial, aerial
However, his system did not work. Why?

3. How Organisms are Classified Today
The 8 Taxa
Organisms are grouped into a series of categories called taxa, each one larger than the previous one.
As you move down the list, each level becomes more specific & includes fewer members than the level above it.
1. Domain
2. Kingdom
3. Phylum
4. Class
5. Order
6. Family
7. Genus
8. Species

4. Classification of the Domestic Dog
Kingdom
Animal
Dog, human, insect, worm, any animals
Phylum
Chordata
Dog, human, fish, other backboned animals
Class
Order
Mammal
Carnivora
Dog, human, whale, all other mammals
Dog, wolf, lion, bear
Family
Canidae
Dog, wolf, fox
Genus
Canis
Dog, wolf
Species
familiaris
Dog

5. Binomial Nomenclature- 2 part naming system
In the 1700’s, Swedish botanis Carolus Linnaeus created the binomial nomenclature naming system still used today
It gives each kind of organism a two-part name, the first part of an organism’s name identifies the genus
The second part of the name identifies the species

6. Domains & Kingdoms Domains Kingdoms Characteristics Bacteria
Eubacteria
Single-celled prokaryotes; oldest organisms on Earth
Archaea
Archaebacteria
Single-celled & don’t have peptidoglycan in cell walls
Eukarya
Protist, Fungi, Plant, Animal
All are eukaryotes

7. Domain Eukarya Protist Single or Multi Cells have a nucleus
Kingdom
Cell number
Cell characteristics
Organisms
Protist
Single or
Multi
Cells have a nucleus
Algae, protozoa
Fungi
Single or multi
Cells have a wall &
nucleus; no chloroplasts
Yeast & mushrooms
Plants
Cells have a wall, nucleus & chloroplasts
Moss, ferns, trees, flowering plants

8. Domain Eukarya Animals Multi
Cells have a nucleus, but no wall or chloroplasts
Sponges, worms, insects, mammals, fish, amphibians, reptiles & birds