I. Introduction What istaxonomy? The branch of biology that groups organisms based on common characteristics. Why do scientists classify? Over 1.5 million species have been identified. Biologists classify to organize and study these organisms.
I. Classification Systems • A. Aristotle (almost 2000 years ago) grouped organisms into two groups: Animals Plants Grouped based on the differences in stems Ex. woody vs. herbaceous Grouped based on general habitat Ex. land, air, or water dwellers
Was Aristotle’s grouping system adequate? Problems with the system…
I. Classification Systems • Carolus Linnaeus (mid 1700’s) • grouped organisms into seven levels ranging from general to specific: Kingdom Phylum Class Order Family Genus Species
Example: • Human Being = Kingdom: Phylum: Class: Order: Family: Genus: Species: Animalia Chordata Mammalia Primate Hominidae Homo Sapiens
I. Classification Systems • Binomial Nomenclature • The scientifc name of an organism, consists of two parts…genus & species. **Scientific name must be either underlined or italicized!** • Examples: • Ursus horriblis = • Felis domesticus = • Canis familiaris =
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III. Alternate Forms of Classification: Heterotrophic Autotrophic • Organisms that rely on outside sources for nutrients (anything that has to eat!) Organisms that can make their own food through photosynthesis (plants).
Prokaryotic Eukaryotic • Simple cells that lack a true nucleus and membrane-bound organelles • ex. bacteria • More complex cells with a true nucleus • and membrane- bound organelles • ex. plants, animals
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Dichotomous Keys A. Definition a chart consisting of a series of paired, opposite statements that help scientists to classify organisms.
Head Abdomen Some practice…what is it? A pseudoscorpion!
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