Diversity of Life: Introduction to Biological Classification

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Diversity of Life Introduction to
Biological Classification

• By Deanne Erdmann, MS

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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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Classification

• Binomial Nomenclature
• Two part name (Genus, species)
• Hierarchical Classification
• Seven Taxonomic Catagroies
• Systematics
• Study of the evolution of biological diversity

Leucaena leucocephala Lead tree
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Binomial Nomenclature

• Carolus von Linnaeus
• Two-word naming system
• Genus
• Noun, Capitalized, Underlined or Italicized
• Species
• 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

• Taxonomic categories
• Kingdom King
• Phylum Philip
• Class Came
• Order Over
• Family For
• Genus Green
• Species 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
The traditional five-kingdom system
Monera
Protista
Plantae
Fungi
Animalia
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SystematicsEvolutionary 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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Taxonomic Diagrams
Mammals
Turtles
Lizards and Snakes
Crocodiles
Birds
Mammals
Turtles
Lizards and Snakes
Crocodiles
Birds
Cladogram
PhylogeneticTree
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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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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.