Taxonomy The science of naming organisms.

Aristotle Plant or animal? If an animal, does it –Fly –Swim –Crawl Simple classifications Used common names

Carolus Linnaeus Described organisms with two word names, instead of polynomials Developed binomial nomenclature First word = genus name Second word = species name

Why binomial nomenclature? Much easier than a 10+ word name under old “polynomial system” Same name no matter where you go Less confusion Binomial = SCIENTIFIC NAME

Scientific Names You Need to Know Homo sapiens (human) Canis lupus ( gray wolf) Felis domesticus ( domestic cat) Pan pan ( chimpanzee) **Note: genus – capital speices– lower italics or underlined

Taxonomic hierarchy Names organisms and their relationships from very broad to very specific

CLASSIFICATION The grouping of objects or information based on similarities Organisms are ranked from very broad characteristics to very specific ones

All organisms classified in a hierarchy Kingdom Phylum Class Order Family Genus Species Ex: sentence to remember!!

Seperations are made until each organism is classified into its lowest possible level EX: bobcatLynx FamilyFelidae Felidae Genus Lynx Lynx Species rufus canadensis

HUMAN CLASSIFICATION: KINGDOM: Animalia PHYLUM: Chordata CLASS: Mammalia ORDER: Primates FAMILY: Hominidea GENUS: Homo SPECIES: sapiens

What is a species anyway? Biological species concept –A group of actually or potentially breeding natural groups that are reproductively isolated from other groups. »Ernst Mayr, 1924 BSC’s problems –Hybrids Sterile offspring of two different species

How many are out there? Scientists currently estimate that –There are 10 million species worldwide –Over 5 million live in the tropics –Most unnamed species are small or microscopic

Why is taxonomy useful? Helps prevent confusion among scientists Helps to show how organisms are related Can be used to reconstruct phylogenies – evolutionary histories – of an organism or group

A note on cladograms Graph showing when different groups diverged from a common ancestral line Points where they diverge are often noted with a feature that was different between ancestral group and a “new” feature in the group that split off.

Bird Cladogram

The 6 kingdoms –Archaebacteria –Eubacteria –Fungi –Protista –Animal –Plantae

Overview of the 6 kingdoms Archaebacteria –Unicellular –Live in extreme environments –Prokaryotic –Some autotrophic ( make own food); some chemotrophic ( use chemicals for energy ) Eubacteria –Unicellular –Prokaryotic –“Common bacteria” ex: E. Coli –Most are heterotrophic ( can’t make own food)

Overview of the 6 kingdoms Protista –Eukaryotic –Unicellular or colonial –Lots of different life styles – ex: Amoeba, Paramecium, algae –Heterotrophic or autotrophic Fungi –Cell walls made of chitin –Eukaryotic –Multicellular –External heterotrophs –Ex: mushroom, yeast

Overview of the 6 kingdoms Plantae –Eukaryotic & Multicellular –Cell walls made of cellulose –Autotrophic –Trees, flowering plants Animalia –Eukaryotic & Multicellular –No cell walls –Internal heterotrophs –Humans, insects, worms

DICHOTOMOUS KEY Written set of choices that leads to the naming of an organism