Discipline of classifying organisms and assigning each organism a universally accepted name

Classification System Historically, organisms were classified according to general characteristics within groups of organisms, such as whether they had a spinal chord. After Charles Darwin's theories on evolution were presented, classifications began to reflect evolutionary relationships between organisms.

Classification Systems  Referring to organisms by common names was confusing for several reasons. Common names vary among languages Common names vary among languages Different species sometimes share a single common name Different species sometimes share a single common name  Scientists agreed to use a single Greek or Latin name for each species because all 18 th century scientists understood Latin and Greek.  Carolus Linnaeus, a Swedish botanist who lived during the 18th century, developed a two- word naming system called binomial nomenclature.

Linnaeus’ classification system  Based on hierarchical system of levels.  Each level is referred to as a taxon.  The naming system called Binomial Nomenclature uses the last two levels to create a two-word scientific name for each organism. The genus name is capitolized, whereas the species name is just underlined. The genus name is capitolized, whereas the species name is just underlined. Often, the species name is a Latinized description of some important trait of the organism or an indication of where the organism lives. Often, the species name is a Latinized description of some important trait of the organism or an indication of where the organism lives.

Classification systems today are still based on hierarchical categories. There are now three domains called Bacteria, Archaea, and Eukarya. Each kingdom falls into one of the three domains.

The two systems:  Five Kingdom System Monerans Monerans Monerans Protist Protist Protist Fungi Fungi Fungi Animals Animals Animals Plants Plants Plants  Six Kingdom System Archaebacteria Eubacteria Protist Fungi Plants Animals

Taxonomy Example for Humans  Domain  Kingdom  Phylum  Class  Order  Family  Genus  Species  Eukarya  Animal  Chordate  Mammal  Primate  Hominid  Homo  Sapien

Domain Bacteria  Prokaryotic (cells have no nucleus)  Unicellular  Have cell walls containing peptidoglycan.  Extremely diverse group including autotrophs, heterotrophs, aerobes, anaerobes, and parasites.

Domain Archaea  Prokaryotic (cells have no nucleus)  Unicellular  Have cell walls without peptidoglycan.  Many in this group live in extreme environments such as volcanic hot springs and black organic mud devoid of oxygen.  Includes autotrophs, heterotrophs, aerobes, and anaerobes.

Domain Eukarya  All Eukaryotes (cells have a nucleus)  Unicellular or multicellular  Autotrophs or heterotrophs  Examples include unicellular organisms, algae, fungi, plants and animals

Prokaryotic cell Eukaryotic cell

Kingdom Eubacteria  Bacteria, which are simple single- celled organisms that are Prokaryotic (have no nucleus and few organelles).  Have cell walls with peptidoglycan.  Unicellular organisms.  Include autotrophs and heterotrophs.  Examples include Streptococcus, and E. coli.

Streptococcus bacteria Staphylococcus aureus E. coli bacteria

Kingdom Archaebacteria  Bacteria, which are simple single- celled organisms that are Prokaryotic (have no nucleus and few organelles).  Have cell walls without peptidoglycan.  Unicellular organisms.  Include autotrophs and heterotrophs.  Examples include Methanogens and halophiles

Halobacteria M. jannaschii

Kingdom Protista  Protists are single and multicellular organisms most of which live in water.  Plant like protists contain chloroplasts and make their own food. Ex) Algae, Kelp  Animal like protists are single celled and move by using pseudopodia, flagella, or cilia. Ex) Amoeba, Paramecium  Fungus like protists include water molds and mildews.

Fungus-like protist Stylonychia Plant-like Protists Chlorophytes (green algae) Animal-like protists Amoeba

Kingdom Fungi  Fungi can be unicellular but are mostly multicellular organisms that decompose dead matter in our environment.  They are heterotrophs and are responsible for doing a major cleaning role in our environment.  Fungi are found in soil, dead trees and even on your bread sometimes.

Kingdom Plantae  Plants are multicellular organisms that are characterized by their tough cell walls and photosynthetic abilities.  They are producers and make up the base of the food chain.  Divided into groups which include mosses, liverworts, horsetails, club mosses, ferns, gymnosperms ( cone bearing plants), and angiosperms ( flowering plants).

Kingdom Animalia  The Animal Kingdom is very diverse and very large, numbering over one million identified species.  Some are vertebrates (backbone), while most (97%) are invertebrates (no backbone).  All animals share the following characteristics; cannot make own food, digest their food, move from place to place, and have many Eukaryotic cells.

Identify the Kingdom

Identify the Phylum

Identify the Class