Diversity of Life: Biological Classification

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Diversity of Life 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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Taxonomy - Classification

• Binomial Nomenclature
• Two part name (Genus, species)
• Hierarchical Classification
• Seven Taxonomic Categories (Linnaeus)
• Three domains
• 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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BACTERIA

• EUBACTERIA
• Prokaryote, Cell Walls with peptidoglycan,
• Unicellular, Autotrophic or Heterotrophic.
• ARCHAEBACTERIA
• Prokaryote, Cell Walls without
• peptidoglycan, Unicellular, Autotrophic
• or Heterotrophic. They live in extreme
  environments.

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PROTISTA

• Cell walls of cellulose in some
• Some have chloroplasts
• Most unicellular some colonial
• Some multicellular
• Autotroph or Heterotroph

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FUNGI

• Eukaryote
• Cell walls of chitin
• Most multicellular some unicellular
• Heterotroph

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PLANTAE

• Eukaryote
• Cell walls of cellulose chloroplasts
• Multicellular
• Autotroph

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ANIMALIA

• Eukaryote
• No cell walls or chloroplasts
• Multicellular
• Heterotroph

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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