CLASSIFICATION Why Classification? * Study the diversity of life * Group and name organisms in a logical manner Taxonomy: science of classifying living and creating scientific names. Early Classification Aristotle: 350 B.C. * Greek philosopher who classified organisms into two kingdoms: Plants or Animals Plants: size and structures Animals: behavior and habitat * What might be some problems with his system? Video Clip http://www.glencoe.com/sec/science/biology/bio2000/biomovies/e20_1int.html Linneaus: Mid 1700s: developed a new classification system His system grouped organisms based on morphology (physical appearance) Created 7 taxonomic levels Carolus Linnaeus (1707-1778) Linnaeus’ Taxonomic levels 7 taxonomic levels (taxon=category) : Kingdom, Phylum, Class, Order, Family, Genus, Species Phrase to remember order of levels: King Phil Came Over From Germany Swimming! 7 Taxonomic levels Can be compared to our address system Kingdom (broadest)----- Country Phylum -------------------- State Class----------------------- County Order -------------------- City Family -------------------- Neighborhood Genus -------------------- Street Species (most specific)- House # What is a Species? Group of similar organisms that reproduce NATURALLY and create FERTILE offspring Leopard Binomial Nomenclature Scientific Names Scientists avoid using common names to prevent confusion because they vary from region to region. Blue Jay Eastern Blue Jay Cyanocitta cristata Blue Jay Western Blue Jay Cyanocitta stellari Binomial Nomenclature Scientific Names 2 part naming system that consists of genus and species. Rules for writing scientific names: Genus: first word - first letter capitalized Species: second word - lowercase Both are underlined or italicized EX: Homo sapiens : Human beings Ursus americanus: American Black Bear Modern Classification Problems with traditional system: focused only on morphology (appearance) Modern Criteria for Classification uses: *Morphology/Anatomy *Development *DNA Comparison- DNA sequences *Evolutionary descent Evolutionary Classification Cladistics: the science of grouping organisms based on evolutionary descent, not just morphology. Cladogram: a diagram that shows evolutionary relationships among organisms. Derived character: characteristic that appears in recent parts of a lineage, but not in the older members. Used to build cladograms. Cladogram www.biologycorner.com/cladogram/cladogram_2.htm#