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CLASSIFICATION. Why Classification? * study the diversity of life. * group and name organisms in a logical manner. Taxonomy : science of classifying living things using scientific names. Early Classification. Aristotle: 350 B.C.
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CLASSIFICATION • Why Classification? * study the diversity of life. * group and name organisms in a logical manner. Taxonomy: science of classifying living things using 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????
Linneaus: Mid 1700s: developed a new classification system • His system grouped organisms based on morphology (physical appearance) • Created 7 taxonomic levels
Linnaeus’ Taxonomic levels • 8 taxonomic levels (taxon=category) : Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species Phrase to remember order of levels: Dear, King Phil Came Over From Germany Swimming!
8 Taxonomic levelsCan be compared to our address system • Domain (broadest)------ Continent • Kingdom ------------------ Country • Phylum -------------------- State • Class----------------------- County • Order -------------------- Town • Family -------------------- Neighborhood • Genus -------------------- Street • Species (most specific)- House #
What is a Species? • Group of similar organisms that reproduce NATURALLY and create FERTILE offspring
Example • http://www.biologycorner.com/bio3/notes-chap20.html
Binomial NomenclatureScientific Names Scientists avoid using common names to prevent confusion because they vary from region to region. Eastern Blue JayWestern Blue Jay CyanocittacristataCyanocittastellari
Binomial NomenclatureScientific 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 Sialia sialis: Eastern Bluebird
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#