1. Classification Notes

2. Taxonomy
Naming and grouping organisms according to their characteristics and evolutionary history.

3. Aristotle
Greek philosopher who first attempted to classify living organisms
Over 2000 years ago

4. Aristotle
He classified living things into two groups:
Plants
Animals

5. Aristotle Why did his system create problems?
Not all living things are plants and animals
Even plants and animals are very diverse
Our knowledge of life has changed

6. Carolus Linnaeus
Swedish scientist who developed our modern system of classification.

7. Carolus Linnaeus
Used morphology (form and structure) to categorize organisms

8. Carolus Linnaeus Developed a hierarchy of levels in his system
Kingdom King
Phylum Phillip
Class Came
Order Over
Family For
Genus Good
Species Soup

9. Species
Remember that a species is a group of organisms that can mate and reproduce fertile offspring
Not a clear cut definition

10. Common Names Most people use common names for organisms
This causes problems
13 lined ground squirrels are often called gophers

11. Scientific Names Scientific names solve the naming problem
Latin is used for most scientific names.

12. Binomial Nomenclature
All organisms are given a genus and a species name.
This way all people can use the same name to identify organisms

13. Genus and Species
The genus name comes first and begins with a capital letter.
Ex. Felis (it can be abbreviated as F.
The species names comes second and begins with a lower case letter.
Ex. domesticus
*Both the genus and species names are usually italicized and often underlined.
Ex. Felis domesticus

14. How do we classify organisms today?
Not so much on physical similarities (can be based too much on opinions).
Scientific evidence is a better way to do this.

15. Evidence for Classification
Chromosome Structure
Biochemical Similarities
Embryology
DNA Sequencing
Reproduction

16. Systems of Classification
Linnaeus used 2 Kingdoms
Plant
Animal

17. The Three-Domain System
Molecular analyses have given rise to a new taxonomic category that is now recognized by many scientists.
The domain is a more inclusive category than any other — larger than a kingdom.
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18. The Three-Domain System
The three domains are:
Eukarya, which is composed of protists, fungi, plants, and animals.
Bacteria, which corresponds to the kingdom Eubacteria.
Archaea, which corresponds to the kingdom Archaebacteria.
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Domain Bacteria
Domain Bacteria
Members of the domain Bacteria are unicellular prokaryotes.
Their cells have thick, rigid cell walls that surround a cell membrane.
Their cell walls contain peptidoglycan.
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Domain Archaea
Domain Archaea
Members of the domain Archaea are unicellular prokaryotes.
Many live in extreme environments.
Their cell walls lack peptidoglycan, and their cell membranes contain unusual lipids not found in any other organism.
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Domain Eukarya
Domain Eukarya
The domain Eukarya consists of organisms that have a nucleus.
This domain is organized into four kingdoms:
Protista
Fungi
Plantae
Animalia
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22. Modern Kingdoms Animalia Plantae Fungi Protista Archaebacteria
Eubacteria

23. Animalia
Multicellular heterotrophs

24. Plantae
Multicellular autotrophs

25. Fungi Most are multicellular Yeast is unicellular
Absorb food through cell walls

26. Archaebacteria Unicellular prokaryotes Related to first life forms
Live in harsh environments

27. Eubacteria
Unicellular prokaryotes
Includes most bacteria

28. Classification of a human
Kingdom = Animalia
Phylum = Chordata
Class = Mammalia
Order = Primate
Family = Hominid
Genus = Homo
Species = sapien