Classifying Organisms By: Stephan Billingslea 7-C

Linnaeus During the late eighteenth century, Carolus Linnaeus developed a classification system based on looking for organisms with similar structures. Linnaeus

 Long ago, Aristotle observed living things. He classified organisms either as animals or plants. Then, he broke this two groups into sub- groups. After Aristotle, no one way of classifying was accepted by everyone. Early History Aristotle

 Like Linnaeus, modern scientists use similarities in structure to classify organisms, using internal and external features. Additionally, scientists also study hereditary information, early stages of development and fossils to determine an organism´s phylogeny. Modern Classification Phylogeny Example

Six Kingdoms Today, organisms are normally divided into six kingdoms. Kingdoms can be divided into smaller groups. The smallest classification is the species. Organisms that belong to the same species can mate and make a fertile offspring. Some scientists believe that organisms should be placed into domains, which are larger than kingdoms. The three domains are; Bacteria, Eukaryota and, Archea. Phylogentic Tree

 Binomial nomenclature gave each species a two- word, unique scientific name. the first word is the organism´s genus, the second is the specie. This avoid misunderstandings between organisms. Scientific Names Scientist use binomial nomenclature to classify organisms and avoid misunderstandings.

 They help avoid mistakes between organisms.  Organisms with similar evolutionary history are grouped together.  Scientific names give descriptive information about organisms.  Scientific names allow information about organisms to be organized easily and efficiently. Uses of Scientific Names Two-word scientific names are used for four reasons;

 A dichotomous key is a detailed list of identifying characters for organisms. If you learn how to use a dichotomous key, you can identify any organism and name it´s species. Dichotomous Keys Tools for identifying organisms include field guides and dichotomous keys. They have descriptive information about organisms.

Vocabulary Phylogeny: The evolutionary history of an organism, or how it has changed over time. Kingdom: The first and largest category in which organisms are placed into. Binomial Nomenclature: The system used by modern scientists to name organisms. Genus: A group of similar species, the second word in a scientific name, that might tell you something about the organism – what it looks like, where it is found, or who discovered it. Dichotomous Key: A detailed list of identifying characteristics that includes scientific names. They are arranged into steps that include two descriptive statements about each step.