CLASSIFICATION
Why Classification?
* Study the diversity of life
* Group and name organisms in a
logical manner
Taxonomy: science of classifying living
and creating scientific names.
Early Classification
Aristotle: 350 B.C.
* Greek philosopher who classified
organisms into two kingdoms: Plants or
Animals
Plants: size and structures
Animals: behavior and habitat
* What might be some problems with his
system?
Video Clip
http://www.glencoe.com/sec/science/biology/bio2000/biomovies/e20_1int.html
Linneaus: Mid 1700s:
developed a new
classification system
His system grouped
organisms based on
morphology (physical
appearance)
Created 7 taxonomic
levels
Carolus Linnaeus
(1707-1778)
Linnaeus’ Taxonomic levels
7 taxonomic levels (taxon=category) :
Kingdom, Phylum, Class, Order, Family,
Genus, Species
Phrase to remember order of levels:
King Phil Came Over From Germany
Swimming!
7 Taxonomic levels
Can be compared to our address system
Kingdom (broadest)----- Country
Phylum -------------------- State
Class----------------------- County
Order -------------------- City
Family -------------------- Neighborhood
Genus -------------------- Street
Species (most specific)- House #
What is a Species?
Group of similar organisms that
reproduce NATURALLY and create
FERTILE offspring
Leopard
Binomial Nomenclature
Scientific Names
Scientists avoid using common names to prevent
confusion because they vary from region to
region.
Blue Jay
Eastern Blue Jay
Cyanocitta cristata
Blue Jay
Western Blue Jay
Cyanocitta stellari
Binomial Nomenclature
Scientific Names
2 part naming system that consists of genus
and species.
Rules for writing scientific names:
Genus: first word - first letter capitalized
Species: second word - lowercase
Both are underlined or italicized
EX: Homo sapiens : Human beings
Ursus americanus: American Black Bear
Modern Classification
Problems with traditional system: focused
only on morphology (appearance)
Modern Criteria for Classification uses:
*Morphology/Anatomy
*Development
*DNA Comparison- DNA sequences
*Evolutionary descent
Evolutionary Classification
Cladistics: the science of grouping
organisms based on evolutionary descent,
not just morphology.
Cladogram: a diagram that shows
evolutionary relationships among organisms.
Derived character: characteristic that appears
in recent parts of a lineage, but not in the
older members. Used to build cladograms.
Cladogram
www.biologycorner.com/cladogram/cladogram_2.htm#