1. The science of describing, naming and classifying organisms
Taxonomy
The science of describing, naming and classifying organisms

2. Classification
Putting things into orderly groups based on similar characteristics
Classification is a PART of taxonomy.

3. Why Scientists Classify Things
Helps make order of living things
Makes it easier for scientists to answer questions
How many known species are there?
What are the defining characteristics of each species?
What are the relationships between these species?

4. History of Classification
Aristotle was the first person known to classify living things.
Before the 1600s living things were classified as plants or animals.
Two major problems with this classification scheme:
Not very specific – animals and plants are 2 broad categories
What about bacteria, archaebacteria, fungi, and protists?

5. History of Classification – cont.
1700s - Carolus Linnaeus founded modern taxonomy
Taxonomy - the science of describing, naming and classifying organisms
Binomial nomenclature – (bi=two, nom=name)
Genus species
Example: Homo sapiens = Humans
Common name = Humans
Specific name = sapiens
Scientific name = Homo sapiens

6. The Old System – 5 Kingdoms

7. The New System - 6 Kingdoms
Archaebacteria
Eubacteria

8. The Newest System – 3 Domains

9. Modern Classification System
Domain  Do
Kingdom  Kings
Phylum  Play
Class  Cards
Order  On
Family  Fuzzy
Genus  Green
Species  Stumps

10. D
DOMAIN
KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES

11. How Scientists Classify Things
Scientists classify organisms based on SIMILAR characteristics
Tools used to identify organisms
Dichotomous keys
Cladograms – branching diagram

12. Dichotomous Key 1a. Organism has 4 legs Go to # 2
Definition: identification aid that uses sequential pairs of descriptive statements
What kind of animal is this?
1a. Organism has 4 legs Go to # 2
1b. Organism has more than 4 legs Go to # 20
2a. Organism has a tail Go to # 3
2b. Organism has no tail Go to # 35
3a. Organism has stripes Bengal Tiger
3b. Organism has no stripes African Lion

13. Cladogram
Figure 2, p. 49
Definition: branching diagram that shows similarities and differences between species
Which 2 animals are the least similar?
Which 2 animals are the most closely related?
Which animals give birth to live young?