1. Classification of Living Things

2. Classification
Biology

3. Taxonomy
Scientists classify organisms and assign each organism a universally accepted name

4. Why Should We Classify Organisms?
To organize similar organisms
So all scientists are discussing the same organisms (species)
Species  population of organisms that share similar characteristics and can breed with one another and produce fertile offspring
Identified 1.5 million species so far
Estimate million have yet to be discovered

5. What tools can we use to show similarities in organisms?
Cladistic analysis  identifies and considers only those characteristics of organisms that are evolutionary innovations – new characteristics that arise as lineages evolve over time
Cladogram – diagram that shows evolutionary relationships among a group of organisms

6. Modern Evolutionary Classification
Darwin’s ideas about descent gave rise to the study of phylogeny – evolutionary relationships among organisms
Evolutionary Classification – Grouping of organisms based on evolutionary history

7. Traditional Classification Versus Cladogram
Appendages
Conical Shells
Crustaceans
Gastropod
Crab
Barnacle
Limpet
Crab
Barnacle
Limpet
Molted exoskeleton
Segmentation
Tiny free-swimming larva
CLASSIFICATION BASED ON VISIBLE SIMILARITIES
CLADOGRAM

8. Genes of many organisms show important similarities at a molecular level. Similarities in DNA can be used to help determine classification and evolutionary relationships

9. Carolus Linnaeus
Swedish botanist that developed a two-word naming system called BINOMIAL NOMENCLATURE
Gives the Genus and species name, written in italics or underlined
Language is usually Latin
Example:
House cat – Felis domesticus
Dog – Canis familaris
Human – Homo sapien

10. Linnaeus’s System of Classification (8 Levels/ Taxa)
Domain (most inclusive, less in common)
Kingdom
Phylum
Class
Order
Family
Genus
Species (less inclusive, more in common)
Each level is called a TAXON; taxa (plural)

11. Figure 18-5 Classification of Ursus arctos
Giant panda
Abert squirrel
Coral snake
Grizzly bear
Black bear
Red fox
Sea star
KINGDOM Animalia
PHYLUM Chordata
CLASS Mammalia
ORDER Carnivora
FAMILY Ursidae
GENUS Ursus
SPECIES Ursus arctos

12. Domains
Currently, all organisms are grouped into 1 of 3 domains which reflect evolutionary relationships
1) Bacteria
2) Archaea
3) Eukarya
EUKARYA
ARCHAEA
Kingdoms
BACTERIA
Eubacteria
Archaebacteria
Protista
Plantae
Fungi
Animalia
LUCA – last universal common ancestor