Taxonomy and Classification

Species 13 billion known species of organisms – Only 5% of all organisms that ever lived – New species are still being found and identified

Classification Vs. Taxonomy Classification = grouping organisms based on similarities Taxonomy = branch of biology that groups and names organisms based on characteristics What are Taxonomists?

Classification Accurately and uniformly names organisms – Ex. starfish (Asteroidea) and jellyfish (Medusozoa) are not actually fish Use same language for all names (Latin and Greek)

Confusion of common names in different languages Latin name is the same by all taxonomists

How do we classify organisms? DNA/protein analysis Embryology = study of organism’s early stages of life Anatomy = body parts and morphology (form) Phylogeny = evolutionary history of an organism

History! Aristotle ( ) = first Taxonomist Classification by type and definition of an organism – Grouped by similarities – Divided into 2 groups: Plants and Animals Subdivided by habitat

What is the problem with this classification system?

History! John Ray (1685) = botanist – First to use Latin for naming plants – First to use the word “species” Names were long telling descriptions of everything about the plant

History! Carolus Linnaeus ( ) = Father of Taxonomy – Classified organisms by their structure Developed a two-named system still used today! – Binomial Nomenclature (Genus and Species)

Standardized Naming Ex. Homo sapiens In Latin (some Greek) 1 st word = genus (capitalized) 2 nd word = species (lower case) – Both words are italicized American Robin

Classification Groups Taxon = category into which related organisms are placed Hierarchy of taxa from broad to specific – Domain = group of similar kingdoms – Kingdom = group of similar phyla – Phylum = group of similar classes – Class = group of similar orders – Order = group of similar families – Family = group of similar genera – Genus = group of similar species – Species = group of organism that can interbreed and produce fertile offspring

Classification 3 Domains – Bacteria – Archaea – Eukarya 4 Kingdoms – Protista – Fungi – Plantae – Animalia Which is Which? Ursus maritimus Ursus americanus Bufo americanus

Dumb King Phillip Cried Out For Goodness Sake!

Cladogram/Phylogenetic Tree Diagram showing organism’s evolutionary history C D E F A B Common Ancestor Which 2 organisms are most closely related? A&B or A&C A&C or C&D

Dichotomous Key Used to identify organisms Key that contains pairs of contrasting descriptions Read both characteristics – Either go to another set of characteristics or identify the organism

Example!!!

A B