Diversity of Life:
Introduction to
Biological
Classification
By Deanne Erdmann, MS
BioEd
BioEdOnline
Online
Why Do We Classify Organisms?
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Biologists group organisms to represent
similarities and proposed relationships.
Classification systems change with
expanding knowledge about new and
well-known organisms.
Tacitus bellus
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Classification
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Binomial Nomenclature
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Hierarchical Classification
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Two part name (Genus, species)
Seven Taxonomic Catagroies
Systematics
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Study of the evolution of biological diversity
Leucaena leucocephala
Lead tree
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Binomial Nomenclature
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Carolus von Linnaeus
Two-word naming system
 Genus
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Noun, Capitalized,
Underlined or Italicized
Species
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Descriptive, Lower Case,
Underlined or Italicized
Carolus von Linnaeus
(1707-1778)
Swedish scientist who laid
the foundation for modern
taxonomy
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Hierarchical Classification
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Taxonomic categories
 Kingdom
King
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Phylum
Class
Order
Philip
Came
Over
Family
Genus
Species
For
Green
Soup
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Kingdoms and Domains
The three-domain system
Bacteria
Archaea
Eukarya
The six-kingdom system
Bacteria
Archaea
Protista
Plantae
Fungi
Animalia
Plantae
Fungi
Animalia
The traditional five-kingdom system
Monera
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Protista
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Systematics:
Evolutionary Classification of Organisms
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Systematics is the study of the evolution of biological
diversity, and combines data from the following areas.
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Fossil record
Comparative homologies
Cladistics
Comparative sequencing of DNA/RNA among
organisms
Molecular clocks
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Taxonomic Diagrams
Mammals
Turtles
Lizards and
Snakes
Crocodiles
Phylogenetic
Tree
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Birds
Mammals
Turtles
Lizards and
Snakes
Crocodiles
Birds
Cladogram
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Dichotomous Keys Identify Organisms
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Dichotomous keys versus evolutionary classification
Dichotomous keys contain pairs of contrasting
descriptions.
After each description, the key directs the user to
another pair of descriptions or identifies the organism.
Example:
1. a) Is the leaf simple? Go to 2
b) Is the leaf compound? Go to 3
2. a) Are margins of the leaf jagged? Go to 4
b) Are margins of the leaf smooth? Go to 5
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Thank You
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This concludes a brief review of biological
classification.
You may find additional information on this section of
in the expanded content talks and in the notes below
each slide in the slide library.
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