Taxonomy
The science of classifying organisms.
Classify
To arrange according to similarities or
differences.
Why classify?
Biologists use classification to organize living
things into groups so that the organisms are
easier to study.
We classify to make our lives easier.
History of Taxonomy
Aristotle
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Simple classifications
Used common names
Plant or animal?
If an animal does it have blood?
does it
– Fly
– Swim
– Walk/Crawl
• DISCUSSION QUESTION - Using Aristotle's 3group system (based on movement), name 2
animals that would fit each of the 3 groups.
Problems with this system?
Some animals can walk, swim, and fly
What technology helped scientist
improve the classification system?
Microscope -1600s
Carolus Linnaeus 1700s
• Described organisms with two word names,
instead of polynomials
• Developed binomial nomenclature
• First word = Genus name (Capitalized)
• Second word = species name (lowercase)
scientific name
– Example Canis lupus
Always italicized or underlined
Why binomial nomenclature?
• Binomial - 2 name
• Nomenclature – naming system
• Much easier than a 10+ word name under old
“polynomial system”
• Same name no matter where you go (Latin)
• Less confusion
Devil Cat
Ghost Cat
Mountain Lion
Screaming Cat
Puma
Florida Panther
Cougar
Felis concolor
Taxonomic Hierarchy
• Names organisms and their relationships from
very broad to very specific
Classification of Living Things
Milky way
Solar System
Earth
U.S.
Ohio
Westerville
Mainsail Dr.
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Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Three Domains of Life
There used to be 2,
why do you think there
are 3 now?
Domain Archaeabacteria: Life's
Extremists...! Archaea are found in
the harshest environments on Earth,
and are the oldest known organisms
on Earth, appearing in the fossil
record over 3.6 BILLION years ago
(3,600,000,000 years ago!)
Domain Bacteria (or Eubacteria):
is familiar to most people when associated
with human or animal disease. However,
most bacterial species do not (and cannot)
cause disease.
Most species even play beneficial roles for
humans by producing antibiotics and
food.
Domain Eukarya
A single-celled or multicellular organism whose
cells contain a distinct membrane-bound
nucleus.
(Organism’s cell has a nucleus.)
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Pro = before
Why has taxonomy changed
throughout history?
Do you think it will continue to
change?
Prokaryotes
• We are now filling out our charts
Archaea
• Unicellular prokaryotes
• Autotrophs
• Cell wall
Eukaryotes
Eu = true
Have membrane bound
nuclei
•Most are
unicellular
Phylum examples
• Chordata Cord Chordates Hollow dorsal
nervous chord, notochord, pharyngeal slits,
endostyle, post-anal tail about 100,000+
Cnidaria Stinging nettle Coelenterates
Nematocysts (stinging cells) about 11,000
Ctenophora Comb bearer Comb jellies Eight
"comb rows" of fused cilia about 100 modern
species
Cycliophora Wheel carrying Symbion Circular
mouth surrounded by small cilia
Classification of Humans
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Kingdom
Phylum
Class
Order
Family
Genus
Species
Animalia
Chordata
Mammalia
Primates
Hominidae
Homo
sapiens
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Is your table filled out?
Don’t lose it!!!