17.1 The Linnaean System of Classification
KEY CONCEPT
Organisms can be classified based on physical
similarities.
17.1 The Linnaean System of Classification
Biodiversity

The variety of life forms in a given
area or ecosystem.

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Close to 2 million species on earth have been
identified.
Scientists estimate 10 to 100 million species
actually exist on earth.
17.1 The Linnaean System of Classification
Why do we classify living Organisms?

To make this great biodiversity easier to
study!
17.1 The Linnaean System of Classification
Early Classification – Aristotle (384 to 322 BC)
• Greek Scholar
• Divided animals into three groups
• Those that fly
• Those that swim
• Those that crawl or walk
17.1 The Linnaean System of Classification
Linnaean Classification System
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Developed in the mid 1700’s
by Swedish botanist named
Carolus Linnaeus.
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Classifies all organisms as
animals or vegetable (plant)
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Gave all organisms a two part
Latin name.
17.1 The Linnaean System of Classification
• Why did Carolus Linnaeus develop this system?
The yellow and white
flower with many
small petals
The yellow and
white flower with
no obvious scent
The pretty flower with a
fuzzy yellow center
surrounded by white
petals which attracts
small bees.
Carl Linnaeus – Chrysanthemum leucanthemum
17.1 The Linnaean System of Classification
Taxonomy
• Taxonomy is the science of naming and
classifying organisms.
• A taxon (taxa – plural) is a group of
organisms in a classification system.
• Organisms are classified based on
physical and structural similarities.
17.1 The Linnaean System of Classification
How it’s organized
• Linnaean
classification
system has seven
levels.
• Each level is
included in the level
above it
• Levels get
increasingly specific
from kingdom to
species.
17.1 The Linnaean System of Classification
Seven Levels of classification

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1. Kingdom
2. Phylum
3. Class
4. Order
5. Family
6. Genus
7. Species
King Phillip Came Over
From Germany Singing.
17.1 The Linnaean System of Classification
Classification Example
Humans
Order
primate
Family
Hominid
Genus
Homo
Species
sapiens
Homo sapiens
17.1 The Linnaean System of Classification
Limitations of Linnaean Classification
• Physical similarities are not always a result of a species
being closely related
• Unrelated species can evolve similar traits.
Modern classifications uses genetic similarities.
17.1 The Linnaean System of Classification

Recent DNA research has changed some long
standing classifications.
DNA evidence puts the giant panda
In the Family – Ursidae (Bears)
17.1 The Linnaean System of Classification
Binomial nomenclature
• A naming system that gives each species a unique
two part name.
• Uses Latin and Greek words.
• Uses the Genus and Species as first and last name.
White oak:
Quercus alba
17.1 The Linnaean System of Classification
Advantages over common names:
• Scientific names help scientists to communicate.
– Some species have very similar common names.
– Some species have many common names.
17.1 The Linnaean System of Classification
• Genus - includes one or more physically similar species
that are closely related.
– Always written in italics and Capitalized
• Species – a group of organisms that can
successfully breed and produce offspring.
– Always written in italics and lowercase
Tyto alba
17.1 The Linnaean System of Classification
Breeding of animals of two different species.
• Not a new species
• Produces infertile offspring
17.1 The Linnaean System of Classification
17.1 The Linnaean System of Classification
Binomial Nomenclature
Family
Family Felidae (Cats)
Tiger - Panthera tigris
Genus and species
are always italicized
OR underlined if
hand written
Lion - Panthera leo
First letter of the
genus is capitalized
Kitten – Felis domesticus
First letter of the
species is lowercase
Cougar – Felis concolor
17.1 The Linnaean System of Classification
Let's try some simple naming - Latin
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The brown caterpillar
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Noun first descriptor second.
i.e. caterpillar brown
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Eruca castane
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17.1 The Linnaean System of Classification
Let's try some simple naming - Greek
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The spotted reptile
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Herpeto halio
17.1 The Linnaean System of Classification
Let's try some simple naming - Greek

Reptile with a flat nose.
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Herpeto platyrhino