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: EukaryaKingdom: Animalia Phylum: ChordataClass: MammaliaOrder: Primates

Family: HominidaeGenus: Homo

Species: Homo sapeins

Guess the organism!

To remember the order:

• Domain Dear• Kingdom King• Phylum Phillip• Class came• Order over• Family for• Genus grape• Species 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!

• Which kingdom has “true” bacteria?• Which kingdom has organisms like Volvox, a

protist?• Which kingdom has mushrooms?• Which kingdom has organisms that are ALL

autotrophs? • Which kingdom has “ancient” bacteria?• 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

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 systemBinomial 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.