Bellwork: Why do scientists use latin or greek names for organisms (which can be hard to remember/understand). Wouldn’t it be easier simply to refer to their common name?

Finding order in diversity Section 18.1

How are scientific names assigned? Common names often vary between languages or countries Cougar, puma, panther and mountain lion In UK a buzzard is a hawk, whereas here it is a vulture In the 18th Century, European scientists recognized this confusion, and assigned Latin or Greek names to each species to help clear this up Names were often very log due to the amount of detail Hard to standardize, as scientists focused on different things

What is a Dichotomous key? A Dichotomous key is used to identify organisms through a series of paired statement or questions that describe alternative possible characteristics

Binomial Nomenclature With binomial nomenclature each species is assigned a two part scientific name Always written in italics Polar Bear is Ursus maritimus Ursus - genus organism belongs to (bear) Maritimus – unique to each species Grizzly bear – Ursus arctos System created by Carolus Linnaeus in 1730s

Classifying species in larger groups Both living and fossil organisms are classified into larger groups These groups must have biological significance Organisms in one group are more similar to each other than to organisms in other groups This science is called systematics Goal – to organize living things into groups that have biological meaning Groups are refereed to as taxa

The Linnaean Classification system Carolus Linnean also created a classification system that organized species into taxa that formed a hierarchy Over time his hierarchy expanded to include seven hierarchical taxa Kingdom – All multicellular animals are placed in the kingdom Animalia Phylum – Shared body plan features Class – Similar orders grouped into a class. Example - mammals Order – Closely related families. Example - Camel, llama, deer and cattle – linkage (hoofed animals, even number of toes) Family – Several genera that share many similarities (camel, Llama) Genus - Camels Species – one hump vs two humps King Phillip Came Over For Good Soup!

Classification system

Problems with traditional classification Members of a species determine which organisms belong to a species through who they mate with and produce fertile offspring How is this different from how Linnaean assigned individuals to a species? What do we know that Linnaean did not? Linnaean had no idea about genetics and evolution, but was a hood scientists, and chose his characteristics carefully Many of his groups are still valid under modern classification schemes Modern day systems assign species on the basis of how closlely related organisms are