This document provides an introduction to biological classification, including: - Biologists classify organisms to represent evolutionary relationships and respond to new knowledge. - Carolus Linnaeus established binomial nomenclature using genus and species names. - Classification uses a hierarchical system of seven categories from kingdom to species. - Systematics studies evolution by combining evidence from fossils, anatomy, DNA, and other areas. - Diagrams and dichotomous keys are used to classify and identify organisms.

1. Diversity of Life:
Introduction to
Biological
Classification
By Deanne Erdmann, MS
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2. Why Do We Classify Organisms?
 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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3. Leucaena leucocephala
Lead tree
Classification
 Binomial Nomenclature
 Two part name (Genus, species)
 Hierarchical Classification
 Seven Taxonomic Catagroies
 Systematics
 Study of the evolution of biological diversity
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4. Carolus von Linnaeus
(1707-1778)
Swedish scientist who laid
the foundation for modern
taxonomy
Binomial Nomenclature
 Carolus von Linnaeus
 Two-word naming system
 Genus
 Noun, Capitalized,
Underlined or Italicized
 Species
 Descriptive, Lower Case,
Underlined or Italicized
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5. Hierarchical Classification
 Taxonomic categories
 Kingdom King
 Phylum Philip
 Class Came
 Order Over
 Family For
 Genus Green
 Species Soup
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6. Kingdoms and Domains
Bacteria Archaea Eukarya
Bacteria Archaea Protista Plantae Fungi Animalia
Monera Protista Plantae Fungi Animalia
The three-domain system
The six-kingdom system
The traditional five-kingdom system
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7. Systematics:
Evolutionary Classification of Organisms
 Systematics is the study of the evolution of biological
diversity, and combines data from the following areas.
 Fossil record
 Comparative homologies
 Cladistics
 Comparative sequencing of DNA/RNA among
organisms
 Molecular clocks
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8. Taxonomic Diagrams
Mammals Turtles Lizards and
Snakes
Crocodiles Birds Mammals Turtles Lizards and
Snakes
Crocodiles Birds
Cladogram
Phylogenetic
Tree
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9. Dichotomous Keys Identify Organisms
 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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10. Thank You
 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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