1. Section 18-1: Finding Order in Diversity

2.  Need to describe and name each species to understand and study diversity  Use scientific names to ensure talking abut the same animal  Common names translate, vary  Ex. Felis concolor commonly known as cougar, puma, panther, mountain lion

3.  18 th century Europeans used Latin or Greek names to describe species based on traits  Did not work – not standardized  1730s: Swedish botanist Carolus Linnaeus developed a two-word naming system called binomial nomenclature  Scientific name usually Latin, written in italics  First word capitalized, second lowercase

4.  Polar bear is Ursus maritimus.  First part of the name is the genus, which is a group of similar species  Second part of unique to each species and is often a description of the organism’s habitat or of an important trait

5.  Biologists try to organize/classify living and fossil species into larger groups that have biological meaning  Groups called taxa (singular: taxon)  The science of naming and grouping organisms is called systematics

6.  Hierarchy  Organisms grouped by anatomical similarities and differences  Linnaeus had four levels, which expanded to seven taxa

7.  Species,  Genus,  Family,  Order,  Class,  Phylum,  Kingdom

9.  Members of a species determine which organisms belong to that species  Ranks above species are determined by researchers who decide  Linnaeus grouped organisms into larger taxa according to overall similarities and differences

10.  Example: adult barnacles and limpets live attached to rocks, have similar-looking shells  Adult crabs don’t look anything like them, and would probably be in a different group  Wrong!  Modern classification schemes look beyond overall similarities and differences and group organisms based on evolutionary relationships