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17 terms

Chapter 18.1 and 18.2 - Classification

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How are living thing organized for study?
Biologists use a classification system to name organisms and group them in a logical manner
Taxonomy
Scientists classify organisms and assign each organism a universally accept the name
What is Linnaeus's system of classifciation?
Includes seven levels (smallest to largest) --> species, genus, family, order, class, phylum, and kingdom
Binomial Nomenclature
Developed by Carolus Linnaeus; it is a two-word naming system; each species is assigned a two-part scientific name; always written in italics and the first word is capitalized and the second word is lowercased
Taxon
Group or level of organization into which organisms are classified
Family
Group of genera that share many characteristics
Order
Griyo if similar families
Class
Group of similar orders
Phylum
Group of closely related classes
Kingdom
Large taxonomic group, consisting of closely related phyla
How are evolutinary relationships important in classification?
Biologists now group organisms into categories that represent lines of evolutionary descent, or phylogeny, not just physical similarities
How can DNA and RNA help scientists determine evolutionary relationships?
The genes of many organisms show important similarities at the molecular level; similarities in DNA can be used to help determine classification and evolutinary relationships
Phylogeny
Evolutionary relationships among organisms
Evolutionary Classification
The strategy of grouping organisms together based on their evolutionary history
Derived Character
Characteristics that appear in recent parts of a lineage but not in its older members
Cladogram
A diagram that shows the evolutionary relationships among a group of organisms
Molecular Clock
Uses DNA comparisons to estimate the length of time that two species have been evolving independently