Taxonomy (Ch 7) The scientific classification of organisms Purpose:  To identify organisms  To provide a basis for natural grouping of things Linnaeus (1700's) developed a system of classification based on an organisms physical and structural features

We now have seven taxa (levels of classification) Kingdom Phylum Class Order Family Genus Species

See if you can make a mnemonic device to help you remember these! Kings Play Chess On Fine Glass Surfaces Hmmm.... Kids Prefer Cheese Over Fried Green Spinach or.....your own!

Individual animals are named using: binomial nomenclature This was first started by Linnaeus A two part latin name including genus and species The first letter of the Genus is capital Both words are underlined Humans: Homo sapiens Black bear: Ursus americanus Polar bear: Ursus arctos

Ursus gelatinus

Sometimes you may not know what something is In that case, you can referto a “dichotomous key” to determine what it is Look at the table on the bottom of page 197 for two different kinds of keys (the first is a spider key, because it branches out into a web. The second is a dichotomous key, which is more like a choose your own adventure novel)

How organisms are classified depends on the criteria used As we move down the taxa (from Kingdom to species) we become more specific

Scientists believe... Single cellled prokaryotic cells (no nucleus) gave rise to single cells eukaryotic cells (nucleus) Eukaryotic cells (protists) then joined to form multi-cellular organisms Multicellular organisms differentiated by how they obtain energy