Diversity of Life: Introduction to Biological Classification By Deanne Erdmann, MS BioEd Online

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 BioEd Online

Leucaena leucocephala Classification Binomial Nomenclature Two part name (Genus, species) Hierarchical Classification Seven Taxonomic Catagories Systematics Study of the evolution of biological diversity Leucaena leucocephala Lead tree BioEd Online

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 BioEd Online

Hierarchical Classification Taxonomic categories Kingdom King Phylum Phillip Class Came Order Over Family From Genus Great Species Spain BioEd Online

Kingdoms and Domains BioEd Online 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 BioEd Online

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 BioEd Online

Taxonomic Diagrams BioEd Online Phylogenetic Tree Cladogram Mammals Turtles Lizards and Snakes Crocodiles Birds Mammals Turtles Lizards and Snakes Crocodiles Birds Phylogenetic Tree Cladogram BioEd Online

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 BioEd Online

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. BioEd Online