1. Classification

2. Evolution has lead to a staggering variety or organisms
Biologists have identified and named about 1.5 million species so far
They estimate anywhere between 2 and 100 million additional species have yet to be discovered

3. Taxonomy
The science of classifying and naming organisms

4. Assigning Scientific Names
By the 18th century, European scientists recognized that referring to organisms by common names was confusing
Common names vary among regions within a country

5. Mountain Lion

6. Cougar

7. Puma

8. Panther

9. Early Efforts at Naming Organisms
First attempts at standard scientific names often described physical characteristics
As a result, these names could be 20 words long!
Ex.) The English translation of the scientific name of a particular tree might be “Oak with deeply divided leaves that have no hairs on their undersides and no teeth around their edges.”

10. Binomial Nomenclature
Carolus Linnaeus (18th Century)
Swedish Botanist
Developed a system for naming organisms

11. Binomial Nomenclature
Two word naming system

12. Rules for Binomial Nomenclature
Written in italics
First word is capitalized
Second word is lowercased
Ex.)
Genus species
G. species

13. The name often tells you something about the species
Ex.) Tyranosaurus Rex
Tyrant Lizard King

15. Taxon (taxonomic category)
A group or level of organization

17. Linnaeus’s system of classification uses seven taxonomic categories
Kingdom
Phylum
Class
Order
Family
Genus
species
Largest / Least Specific
Smallest / Most Specific

18. Mnemonic Device Kingdom Phylum Class Order Family Genus species King
Phillip
Came
Over
For
Good
Soup

20. Evolutionary Classification
Darwin’s theory of evolution changed the entire way that biologists thought about classification
Biologists now group organisms into categories that represent lines of evolutionary descent, not just physical similarities

21. Derived characteristics
Characteristics that appear in recent parts of a lineage but not in its older members

22. Cladograms
Diagram that shows the evolutionary relationships among a group of organisms

24. In taxonomy, as in all areas of science, ideas and models change as new information arises, some explanations have been discarded altogether, whereas others such as Darwin’s theory of evolution by natural selection, have been upheld
So it should not be surprising that since the 1800’s, the tree of life has been revised and edited since the discovery of all this new information

25. The Tree of Life Evolves
Before Linnaeus’s time, the only two Kingdoms that existed were Plants and Animals
As scientists discovered new organisms that didn’t fit into the plant or animal category, they made a new category

26. The Old 5 Kingdom System
Animals
Plants
Fungi
Protist
Bacteria

27. In recent years, as evidence about microorganisms continued to accumulate, biologists come to recognize that the Monera were composed of two distinct groups

28. The New 6 Kingdom System Animals Plants Fungi Protist Eubacteria
Archaebacteria

30. The Three Domain System
Molecular analysis has given rise to a new taxonomic category that is now recognized by many scientists

31. Domain
Larger than a kingdom

32. 3 Domains Bacteria Eubacteria 2. Archaea Archaebacteria 3. Eukarya
Protists, fungi, plants, animals
(Everything with a nucleus)