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Download 392 Chapter 18 Skeleton Notes - 5-20-12
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Chapter 18 Classification Taxonomy To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner - Also responsible for naming organisms Naming Organisms Common names were becoming too confusing – Every culture had a different name for the same organism – Scientists could not keep track Binomial Nomenclature In binomial nomenclature, each species is assigned a two-part scientific name – First part is the genus name, second part is the species name EX: Human = Homo sapien Hierarchy of Levels Linnaeus’ hierarchical system of classification includes seven levels (taxa) Smallest to largest – Species > Genus > Order > Class > Family > Phylum > Kingdom > Domain Kingdoms There are six kingdoms – Eubacteria - Archaebacteria – Protista - Fungi – Plantae - Animalia Domains Recent classifications have created a grouping larger than kingdoms There are three domains – Eukarya – protists, fungi, plants, animals – Bacteria – eubacteria – Archaea – archaebacteria Phylogeny Grouping is based on phylogeny as well as physical similarities – Grouping organisms based on evolutionary history is called evolutionary classification Molecular Clocks The genes of many organisms show important similarities at the molecular level. Similarities in DNA can be used to help determine classification and evolutionary relationships – The more similarities in DNA between organisms, the closer they are related
