1. Biological Classification

2. Why Classify?
To study the diversity of life, biologists use classification systems to group organisms according to evolutionary relationships (common ancestry). This makes the diversity of life easier to study.
Taxonomy – discipline to group organisms hierarchically and assign each organism a universally accepted name.

3. Carl Linneaus
The modern system of taxonomy used today was created by Carl Linnaeus in the 1700s.
It included a naming system called binomial nomenclature which literally means two-name naming system.

4. Binomial Nomenclature (scientific names)
Generic (genus) name
Specific (species) name
Group of closely related species
Group of organisms maintained by biological mechanisms that result in their breeding mostly with their type (interbreeding)
Rules:
One binomial name for each species
Capitilzed Generic, lowercase specific. Ex: Homo sapiens, Tyrannosaurus rex
3. Constructed according to rules of Latin or Greek grammar
4. Discoverer of species gets naming rights
5. Typed in italics, underlined or cursive when written
6. Names cannot be changed (unless a species is misidentified and already exists)

5. Specific names can’t stand alone!
Centropyge bicolor
Baeolophus bicolor
Boletus bicolor
Labio bicolor
Ecsenius bicolor
Loxocemus bicolor
Phyllobates bicolor
Euphorbia bicolor
Gila bicolor
Epalzeorhynchus bicolor
Rhamnusium bicolor
Chilobrachys bicolor
Calendula bicolor
Lespedeza bicolor
Flabellina bicolor
Eucomis bicolor
Androctonus bicolor
Saguinus bicolor

6. Specific names can’t stand alone!

7. Paracanthurus hepatus
What’s a Blue Tang?
Acanthurus coeruleus
Atlantic
Paracanthurus hepatus
Indo-Pacific

8. Paracanthurus hepatus is commonly called
blue tang
regal tang
hippo tang
palette surgeon fish
flagtail surgeon fish
blue surgeon fish
other languages?
Common names are NOT scientifically useful!

9. Convergent Evolution
Convergent evolution (from different ancestors) produces analogies, which are NOT useful in classification

10. Taxonomic Classification Kingdom Animalia Phylum Chordata Class Aves
Turkey vulture
Red-headed vulture
Kingdom
Animalia
Phylum
Chordata
Class
Aves
Order
Cathartiformes
Accipitriformes
Family
Cathartidae
Accipitridae
Genus
Cathartes
Sarcogyps
Species
C. aura
S. calvus

11. Divergent Evolution
Divergent evolution from a common ancestor produces homologies which are useful in classification

12. Embryos can reveal homologies which are useful in classification
Embryo Comparisons
adult tunicate
Embryos can reveal homologies which are useful in classification

13. DNA Comparisons
Similar DNA sequences are molecular homologies which are useful in classification

14. Taxonomic Classification based on appearance (prior to 2001) Kingdom
Chimpanzee
Human
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Primates
Family
Pongidae
Hominidae
Genus
Pan
Homo
Species
P. troglodytes
H. sapiens

15. Taxonomic Classification based on DNA sequences (post 2001) Kingdom
Chimpanzee
Human
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Primates
Family
Hominidae
Genus
Pan
Homo
Species
P. troglodytes
H. sapiens

16. Biological Classification is Hierarchical
King
Philip
Cut
Open
Five
Green
Snakes
Which taxonomic group has organisms that are most closely related? Least?

18. Caiman
Parrot
T. rex
Animalia
Chordata
Reptilia
Aves