Classifying Living Things

Why Do We Classify? Allows us to keep track of the 3 to 10 million different living things on Earth Classification: The systematic grouping of organisms into categories on the basis of evolutionary relationships or physical appearance The Science of classifying is called “Taxonomy” People have been classifying for nearly 2,000 years

Scientific Naming Carolus Linnaeus Developed systems for naming species and organizing them into groups Named over 4000 plants & animals Used appearance to group species “Father of Taxonomy” Used binomial nomenclature

What is Binomial Nomenclature? “Binomial” = two-name “Nomenclature” = naming system Language: Latin Ex: common house cat – Felis domesticus Mountain lion, puma, cougar – Felis concolor Bobcat – Felis rufus Genus species Always capitalized always lower-case Both are always italicized Genus and species are the most specific levels of organization

There are 8 levels of classification that describe a species Domain Kingdom Phylum Class Order Family Genus Species Eukarya Animalia Chordata Mammalia Carnivora Ursidae Ursus maritimus Eukarya Animalia Chordata Mammalia Primate Hominidae Homo sapiens Eukarya Animalia Chordata Mammalia Carnivora Canidae Canis familiaris The more levels of organization that two organisms share, the more closely related the two organisms are!

Three Domain System Recently, scientists have added a group above Kingdom.  Three groups, called DOMAINS, contain each of the six kingdoms. Domain Eukarya - includes organisms composed of eukaryotic cells (plants, animals, fungi, protists) Domain Bacteria - includes all prokaryotic cells, Kingdom Eubacteria Domain Archaea - includes only "ancient" bacteria, Archaebacteria

The Kingdoms There are currently 6 kingdoms – all organisms can be placed into one of those 6. Classification into a kingdom is based on certain criteria Number of cells How it obtains energy Type of cell

Kingdom Animalia Multicellular Heterotrophic (must consume food) Eukaryotic (cells have a nucleus) Examples: birds, insects, worms, mammals, reptiles, humans

Kingdom Plantae Multicellular Autotrophic (can make own food; photosynthesis) Eukaryotic (cells have nucleus)

Kingdom Fungae Multicellular (most) Heterotrophic (mainly decomposers) Eukaryotic ex. mushrooms, yeast

Kingdom Protista Most are unicellular Can be heterotrophic or autotrophic Eukaryotes (all have nucleus) Examples: Ameba, paramecium, euglena, algae Most live in water

Kingdom Eubacteria & Kingdom Archaebacteria Unicellular Can be autotrophic or heterotrophic Prokaryotes (do not have a nucleus) Eubacteria = common bacteria (E. coli, Salmonella) Archaebacteria = “ancient bacteria”, exist in extreme environments