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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 and creating 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 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 For Good Soup
7 Taxonomic levelsCan be compared to our address system • Kingdom (broadest)----- Country • Phylum -------------------- State • Class----------------------- County • Order -------------------- City • Family -------------------- Zip Code • Genus -------------------- Street • Species (most specific)- House #
What is a Species? • Group of similar organisms that reproduce NATURALLY, with consistent pregnancies, and create FERTILE offspring
Binomial NomenclatureScientific Names • Scientists avoid using common names to prevent confusion because they vary from region to region. Blue Jay Blue Jay Eastern Blue Jay Western Blue Jay Cyanocitta cristata Cyanocitta stellari
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
North American Pocket Mice • Pergonathus californicus • Found in California • Pergonathus nelsoni • Discovered by someone named Nelson • Pergonathus spinatus • Has prickly fur Common Factors-Same genus, different species, so would produce infertile offspring.
Review • What are the eight characteristics of life? • Living things are made of cells • Must reproduce • Same genetic code • Must grow and develop • Must obtain energy • Must respond to environment • Must maintain homeostasis • Must adapt and evolve
Review • What are the 7 taxonomic levels in order from most general to most specific? • Kingdom • Phlyum • Class • Order • Family • Genus • Species
Review • Who created the classification system that is currently in use? • Linnaeus
Review • The two name scientific naming system for organisms is called ____________. • Binomial nomenclature
Review • Which taxon comes first in a scientific name? • Genus
Review • How should you format the scientific name? • Genus- capitalized • Species-lower case • Either underline or italicize
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
Dichotomous Key • Tool for classifying unknown organisms • Uses 2 sets of descriptors, known as couplets • Steps: • Always start at #1 • Follow couplets based on organism’s characteristics
