1. Biologists have identified and named about 1.5 million species.
Classification
Biologists have identified and named about 1.5 million species.
They have estimated that there are probably 2 to 100 million more species yet to be discovered

2. What is the name of this animal?
Why classify?
What is the name of this animal?

3. Depending on what part of the country you live in…
You might call this animal
A puma
A lion
A panther
a cougar

4. Finding order in diversity
Biologists must give each organism a name.
Living things have been organized into groups that have biological meaning:
Structure
Developmental stages
Biochemical analysis
Behavioral patterns

5. The first attempt at naming organisms used physical characteristics in great detail!
Oak with deeply divided leaves that have no hairs on their undersides and no teeth around their edges
Obviously this wasn’t very effective. It was too long and scientists tended to describe different characteristics for the same thing!

6. Binomial Nomenclature
Binomial nomenclature is a system where each species is assigned a two-part scientific name.
* the scientific name is always written in
italics
* the first word is always capitalized

7. Odocoileus hemionus common name: mule deer

8. Binomial nomenclature was developed by a Swedish botanist in the eigthteenth century by the name of Carolus Linnaeus

9. The system that Linnaeus developed is still used today!

10. Linnaeus’ Classification System
Includes seven levels called taxa
The taxa from largest group to the individual organism is as follows:
Kingdom
Phylum
Class
Order
Family
Genus
Species

11. Vocabulary
Binomial nomenclature – each species is assigned a two-part name
Taxonomy – branch of biology that studies the grouping and naming of organisms

12. Modern Evolutionary Classification
Linnaeus’s system has limitations. It is mainly according to visible similarities and differences.
If you lived in Linnaeus’s time how would you classify a dolphin?
Is it a fish?
Is it a mammal?

13. Cladisitic Analysis
Biologists now group organisms into categories that represent lines of evolutionary descent, called phylogeny, not just physical characteristics.

14. Many biologists now prefer a method called cladistic analysis which identifies only those characteristics that are evolutionary. New characteristics that arise over time and appeared only recently and are not in older members are called derived characters Derived characters can be used to construct a CLADOGRAM

16. Kingdoms and Domains
In Linnaeus’s time, life was simple! The only known differences among living things was:

17. The Three-Domain System
Scientists have compared a small piece of ribosomal RNA that occurs in all living things. Using this comparison, we know how long things have evolved independently.
The domain system is more inclusive and includes groups that are larger than a kingdom!

18. Vocabulary
Domain – most inclusive taxonomic category; larger than a kingdom

19. The three domains are: Eukarya: which is composed of protists, fungus, plants and animals Bacteria: which corresponds to the kingdom Eubacteria Archaea: which corresponds to the kingdom archaebacteria

20. Today there are six large groups or Kingdoms
Archaebacteria
Eubacteria
Protista
Fungi
Plantae
Animalia

21. Archaebacteria and Eubacteria
Archaebacteria – prokaryotes, unicellular, cell walls without peptidoglycan, found in extreme environments
Eubacteria – prokaryotes, unicellular, cell walls with peptidoglycan, found almost everywhere!

22. Protista
Eukaryotic, unicellular or multicellular, plant-like, fungus-like, and animal-like

23. Fungi The Earth’s decomposers
Eukaryotic, unicellular or multicellular heterotrophs

24. Plantae Stationary, multicelluar, eukaryotic autotrophs
Most have cellulose cell walls and tissues organized into organs and organ systems

25. Animalia Multicelluar and mobile, eukaryotic heterotrophs
Have tissues organized into complex organ systems