1. Essential question: How and why do we classify organisms?

3. Why Classify? To study the diversity of life Used to name organisms and group them Taxonomy = classify organisms and give them universally accepted name

4. Naming Early Attempts: Used physical description Ex: “Oak with deeply divided leaves that have no hairs on their undersides and no teeth around their edges.” Common names vary among languages Ex: Mountain Lion or puma or cougar

5. Solution: Carolus Linnaeus developed BINOMIAL NOMENCLATURE = two part scientific name. 1.Written in italics with Greek and Latinized words 2.First word Capitalized, second word lower case 3.Genus – 1 st word, species – 2 nd word Ex: Scientific Name – Felis concolor Common Name – Mountain Lion

6. Grizzly Bear Ursus arctos Polar Bear Ursus maritimus Panda Bear Ailuropoda melanoleuca Which two bears are more closely related?

7. Binomial Nomenclature 1.Each organism has 2 scientific names 2.Genus and species 3.Always in italics 4.Genus – upper case, species-lower case 5.Genus can be abbreviated. Tyrannosaurus rex = T. rex

8. Classification Linnaeus’ hierarchical system: Kingdom general Phylum Class Order Family Genus Species specific (King Philip Came Over For Grape Soda) Taxons

9. Linnaeus’s System of Classification “ K ing P hilip C ame O ver F or G rape S oda” Kingdom Phylum Class Order Family Genus Species

10. Kingdoms and Domains 1 st attempts to make the Tree of Life were too inclusive: plant vs. animal Modern tree contains the six kingdoms and their phyla: Eubacteria, Archaebacteria, Protista, Fungi, Plantae, Animalia Domains – newest, largest inclusive category developed from comparing r-RNA subunits. Bacteria, Archaea, Eukarya

11. Phylogeny – evolutionary history of an organism (how it changed over time)

12. Cladogram shows ancestral relations between organisms= evolutionary tree of life. DNA and RNA, computational phylogenetics are now used

13. Modern Classification Just using appearance can be misleading. New system uses: 1. Fossils 2. Dissections/comparative anatomy 3. Molecular similarities/DNA/enzymes-The more genes that are similar, the more closely related 4. Evolutionary similarities or milestones Ex: amniotic sac, jaws, endothermic

15. Molecular Clocks Used to estimate how long ago two species shared a common ancestor. The more dissimilar the genes, the longer ago they shared a common ancestor

16. How do we diagram these evolutionary relationships??? Using a……..

17. ….Cladogram Uses derived characteristics, those that appear in recent parts of a lineage but not in its older members, to construct diagram of evolutionary relationships.

19. Kingdoms Eubacteria Archaebacteria Protista Plantae Fungi Animalia DOMAIN EUKARYA DOMAIN ARCHAEA DOMAIN BACTERIA Section 18-3 Figure 18-13 Cladogram of Six Kingdoms and Three Domains

20. DICHOTOMOUS KEYS a tool to determine the identity of ORGANISMS. Keys consist of a series of choices that lead the user to the correct name of a given item. "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step.