Classification The grouping of objects or information based

Classification The grouping of objects or information based on similarities.

Taxonomy • The discipline of biology that classifies organisms into general to specific categories • Used to avoid confusion caused by regional common names.

Assigning Scientific Names • Carolus Linnaeus: 18 th century Swedish botanist who developed a two word naming system (binomial nomenclature) to specifically name organisms. • These 2 words are called the genus and species – Genus is always capitalized and species is always under case.

Linnaeus’s System A hierarchical system that has 7 levels that become sequentially more specific. • Kingdom • Phylum • Class • Order • Family • Genus • Species Each level is called a taxon, or taxonomic category. Modern Biology has included a larger category called the Domain

• Species and genus are the two smallest categories. Grizzly bear Black bear

Genera that share many characteristics are grouped in a larger category, the family. Grizzly bear Black bear Giant panda

An order is a broad category composed of similar families. Grizzly bear Black bear Giant panda Red fox

• The next larger category, the class, is composed of similar orders. Grizzly bear Black bear Giant panda Class Mammalia Red fox Abert squirrel

• Several different classes make up a phylum. Grizzly bear Black bear Giant panda PHYLUM Chordata Red fox Abert squirrel Coral snake

• The kingdom is the largest and most inclusive of Linnaeus's taxonomic categories. Grizzly bear Black bear Giant panda Red fox KINGDOM Animalia Abert squirrel Coral snake Sea star

Modern Evolutionary Classification • Linnaeus used physical characteristics to group organisms into their taxa. (can be misleading) • Today we use this along with genetic comparisons, fossil records, and biogeography. • Evolutionary Classification: The strategy of grouping organisms together based on their evolutionary history.

Evolutionary Classification • Cladistic analysis: Identifies and considers characteristics (and genes) of organisms that are evolutionary innovations • Derived Characters: characteristics that appear in recent parts of a lineage, but not in the older members. (distinguishing characteristics used in dichotomous keys) • Cladogram: a evolutionary diagram that shows the relationships among a group of organisms. – Use derived characters to do this. – Pg. 453 quick lab

Evolutionary Classification Limpet Crab Barnacle Molted external skeleton Segmentation Limpet Tiny freeswimming larva CLADOGRAM

Evolutionary Classification • Cladograms can be coupled to taxon to show divergence of groups of organisms

Animal kingdom extension Use the dichotomous keys for the Arthropod and Chordata phyla to make cladograms for the classes w/in them. • Make a derived character data table first • Only use characters on the dichotomous key. • DO NOT use the common names, just classes (ie do not use “scorpion”, use “arachnidia”) Extra credit: Complete the going further from the dichotomous Key Lab, make a cladogram for the salamanders (+5)