Classification
and Taxonomy
Order, Organization,
& Naming of all life
on Earth
Classifying Organisms
• Taxonomy: the science of describing,
naming, and classifying organisms
Ways to Classify Organisms
• Unicellular vs. multicellular
• Prokaryote vs. eukaryote
• Autotroph vs. heterotroph
– Makes its own food vs. having
to “get” food
– Simple vs complex feeding
systems.
• Linnean system and binomial
nomenclature (today)
Old Systems of Classification
• Aristotle (Greek, 2400 years ago): classified
only as plant or animal
…but where does this stuff go? 
A better system
• Carolus Linnaeus
(1707-1778)
• “Father of Taxonomy”
• His work is the basis
of classification
systems used today
Modern Classification
• Can classify all life into
3 main domains
– Most general/most
inclusive category
– Bacteria, archaea,
eukarya (written in
chart)
Characteristics of Domain Bacteria
• Prokayote
– Does not have a
nucleus or specialized
organelles
•
•
•
•
Small
Unicellular
Have cell wall
Example: E. coli
Characteristics of Domain Archaea
•
•
•
•
•
Prokayote
Small
Unicellular
Have cell wall
Live in harsh
environments
• Example: Pyrococcus
abyssi
Some of the first
Archaea were found in
the hot springs of
Yellowstone Park
Characteristics of Domain Eukarya
• Eukaryote
– Have a nucleus and
specialized organelles
•
•
•
•
Small or large
Uni. or multi.
Some have cell walls
Ex: protists, fungi,
plants, animals
Be ready to answer!
• How did Aristotle classify organisms?
• Who came along and improved Aristotle’s
method?
• Which domain of life has organisms that live in
very harsh environments?
• Which domain are humans contained in?
• Which 2 domains have prokaryotes?
Domains can be broken into 6 kingdoms
The 6 kingdoms:
• Kingdom Eubacteria (“true” bacteria)
– Prokayote
– Unicellular
– Includes autotrophs and heterotrophs
The 6 kingdoms:
• Kingdom Archaebacteria (“ancient” bacteria)
– Prokayote
– Unicellular
– Autotrophs (chemosynthesis), heterotophs
The 6 kingdoms:
• Kingdom Protista (protists)
– Eukaryote
– Majority are unicellular
– Autotrophs, heterotophs
The 6 kingdoms:
• Kingdom Fungi
– Eukaryote
– Majority are multicellular
– Heterotrophs
The 6 kingdoms:
• Kingdom Plantae (plants)
– Eukaryote
– Multicellular
– Autotrophs
The 6 kingdoms:
• Kingdom Animalia (animals)
– Eukaryote
– Multicellular
– Heterotrophs
“Domain” and “kingdom”
are still too broad.
We continue to break organisms into
more and more specific categories.
Same
information,
just presented
in a different
way
Classification of Humans
Domain:
Kingdom:
Phylum:
Class:
Order:
Family:
Genus:
Species:
Eukarya
Animalia
Chordata
Mammalia
Primates
Hominidae
Homo
Homo sapeins
Guess the organism!
Domain
Eukarya
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Carnivora
Family
Canidae
Genus
Canis
Species
Canis
Lupus
Try again…Guess the organism!
Eukarya
Domain
Animalia
Kingdom
Chordata
Phylum
Mammalia
Class
Carnivora
Order
Canidae
Family
Canis
Genus
Canis familiaris
Species
To remember the order:
•
•
•
•
•
•
•
•
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Dear
King
Phillip
came
over
for
grape
spaghetti
Classifying
organisms
• Taxon: any particular
group within a taxonomic
system
– “Taxa” is plural
– Examples of taxa:
•
•
•
•
Kingdom
Phylum
Class
etc.
Be ready to answer!
1. Which kingdom has “true” bacteria?
2. Which kingdom has organisms like Volvox, a
protist?
3. Which kingdom has mushrooms?
4. Which kingdom has organisms that are ALL
autotrophs?
5. Which kingdom has “ancient” bacteria?
6. Which kingdom has ants?
Why do scientists use Latin to classify
and name organisms?
HERE’S AN
EXAMPLE WHY.
What is this?

This organism can be called
a:
•
•
•
•
•
•
•
•
•
•
•
Cougar
•
Mexican lion
•
Mountain lion
•
Deer tiger
•
Mountain screamer •
Puma
•
Florida panther
•
Catamount
•
Panther
•
Silver lion
•
Devil cat
•
Indian devil
Sneak cat
King cat
Mountain devil
Red tiger
Deercat
Fire cat
Plain lion
Grey lion
Caracajou
Klandagi
•
•
•
•
Catawampus
Quinquajou
Long Tail
Swamp lion
Big Problem!
There are at least 50
common names for
the cougar.
The same issue arises
with many other
organisms!
Why classify with a scientific name?
• Since common names vary,
scientific names ensure
you’re talking about the
correct organism
• Some names are
misleading (“jellyfish”)
Scientific naming system
Binomial nomenclature- a two-part name
system for writing scientific names. Based on
Latin.
Rules
• Genus name written first
– ALWAYS capitalized
• Species name is written second
– NEVER capitalized
– NEVER by itself
• Both words are italicized if typed,
underlined if handwritten
Find the errors!
• Taxidea Taxus
• procyon lotor
• Delphinidae Delphis
Sidenote with an
example:
• Cannis vulpes is a
fox
• Writing C. vulpes is
acceptable.
• Writing Cannis v. is
not.
• Writing vulpes (by
itself) is BAD…need
genus + species.