Taxonomy The science of identifying, classifying, and naming organisms We used Aristotle’s system until the 1700s. He classified living things into animals or plants. He classified animals by how they moved. He classified plants based on their stems. Today, we use Linnaeus’s system. He created a hierarchical system based on morphology. A hierarchical system has levels that start very general and get very specific. Morphology is an organism’s structure, the way it looks.

Modern Taxonomy Relies on DNA in addition to just structural similarities

Levels of Classification Domain Kingdom Phylum Class Did King Phillip Come Over For Grape Soda Order Family Genus Species

A domain is very broad and includes a wide variety of organisms A species is very narrow and includes only one type of organism. Organisms in the same species are able to mate and produce fertile offspring.

Binomial Nomenclature With Linnaeus’s system, we have a way to classify organisms by their morphology and give them names. Each species has a specific scientific name, called its binomial nomenclature, which means TWO-PART NAMING SYSTEM. It is the genus and species. Be careful: we never just say the species without the genus. The genus name always begins with a capital letter. The species is written in lowercase letters. Both names are either italicized or underlined. Scientific names are taken from Greek and Latin.