1. Classification of Organisms
Chapter 14 Notes

2. 14-1 Categories of Biological Classification
Taxonomy – The science of classifying living organisms, based on shared characteristics
Binomial Nomenclature – two-word system for naming organisms
Scientific Names –
Each organism is assigned a unique two-word scientific name. Consists of Genus, species, ex. Homo sapiens
*helps scientists classify newly discovered species

3. Scientific Names (con’t)
These enable scientists to communicate in the same scientific language with each other about organisms, regardless of their own native language
There could be confusion when different cultures, societies, or nations, refer to the same organism by different common names.

4. What Makes Up a Scientific Name?
Two different types of organisms cannot have the same scientific name, so every species has its own unique scientific name.
Ex: All red oaks have the same scientific name (Quercus rubra) because they are all the same species, but willow oaks (Quercus phellos) have a different species than red oaks.

5. Table 1

6. Classifying Organisms
There are 8 levels to the classification hierarchy:
Domain, kingdom, phylum, class, order, family, genus, species (in order from least specific to most specific)
Phrase to help memorize: Did King Phillip Come Over For Grape Soda?

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

8. Example

9. 14-2 How Biologists Classify Organisms
Biological species – a group of natural populations that are interbreeding or that could interbreed, and that are reproductively isolated from other groups

10. Biological Species
Hybrids – offspring that result from interbreeding by individuals of different species
Example: Wolves and dogs
Not all species interbreeding produce fertile offspring (like a horse and a donkey producing a mule)

11. Evolutionary History Phylogeny – an organism’s evolutionary history
Convergent evolution – organisms evolve similar structures independently, usually because they live in similar habitats
a. Example: shark and dolphin

12. Convergent Evolution/Analogous Structures

13. Evolutionary History (con’t)
Analogous structures – similar features that evolved through convergent evolution.
a. Homologous structures are similar because of common ancestry, but analogous structures are similar because of similar natural selection acting on two different species in similar environments.

14. Evolutionary History (con’t)
Cladistics – using shared characteristics to infer relationships between organisms
a. Cladograms – branching diagrams which show the evolutionary relationships among groups of organisms

15. Cladogram

16. Cladistics (con’t)
Ancestral character – a characteristic that evolved in a common ancestor of both groups
Derived character - a characteristic that evolved in an ancestor of one group but not of the other; they are the characteristics listed on the bottom of a cladogram that separate the two groups above it.

17. 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

18. Evolutionary History (con’t)
Phylogenetic tree – another type of branching diagram that shows evolutionary relationships, it separates organisms also on the basis of how important a character is (like feathers on birds)

19. Phylogenetic Tree vs. Cladogram