Classification Chapter 17

17-1 Taxonomy Process of classifying organisms and giving each a universally accepted name Process of classifying organisms and giving each a universally accepted name Used to study organisms and group them in logical manner Used to study organisms and group them in logical manner

Scientific names Usually written in Latin or Greek Usually written in Latin or Greek Naming system developed by Carolus Linnaeus uses two words called binomial nomenclature Naming system developed by Carolus Linnaeus uses two words called binomial nomenclature Each species gets two-part name Each species gets two-part name The first word is capitalized and names the Genus to which the organism belongs The first word is capitalized and names the Genus to which the organism belongs The second word is lower case and unique to the species naming one particular trait The second word is lower case and unique to the species naming one particular trait

Hierarchy of classification Kingdom-largest and very broad Kingdom-largest and very broad Phylum Phylum Class Class Order Order Family Family Genus Genus Species-smallest and very specific Species-smallest and very specific

To return to the chapter summary click escape or close this document. Life’s Six Kingdoms

17-2 Evolutionary classification Categories of classification represent lines of evolutionary descent as well as physical traits Categories of classification represent lines of evolutionary descent as well as physical traits Process call phylogeny Process call phylogeny Members of a genus share a recent common ancestor Members of a genus share a recent common ancestor

Cladograms Identifies characteristics that are new or recently developed called derived characters Identifies characteristics that are new or recently developed called derived characters Used to construct cladograms that show evolutionary relationships among similar organisms Used to construct cladograms that show evolutionary relationships among similar organisms Help scientists understand how one lineage branched from another Help scientists understand how one lineage branched from another

Similarities in DNA and RNA Can be used to determine classification and evolutionary relationships Can be used to determine classification and evolutionary relationships DNA can show how organisms change over time DNA can show how organisms change over time The more similar the DNA, the more recently they shared a common ancestor, the more closely related the organisms are The more similar the DNA, the more recently they shared a common ancestor, the more closely related the organisms are

Molecular clocks Uses DNA comparisons to estimate the length of time two species have been evolving independently Uses DNA comparisons to estimate the length of time two species have been evolving independently Mutations occur all the time causing changes in DNA Mutations occur all the time causing changes in DNA Some cause major effects in phenotype Some cause major effects in phenotype Others are neutral and are used in studies to determine how long ago organisms shared a common ancestor Others are neutral and are used in studies to determine how long ago organisms shared a common ancestor

17-3 Six-kingdom system Eubacteria Eubacteria Archaebacteria Archaebacteria Protista Protista Fungi Fungi Plantae Plantae Animalia Animalia

3-domain system Eukarya-protists, fungi, plants, animals Eukarya-protists, fungi, plants, animals Bacteria-Eubacteria Bacteria-Eubacteria Archaea-Archaebacteria Archaea-Archaebacteria

Domain Bacteria Unicellular Unicellular Prokaryotes Prokaryotes Cells walls contain peptidoglycan Cells walls contain peptidoglycan Ecologically diverse Ecologically diverse Range from free-living to parasites Range from free-living to parasites

Domain Archaea Unicellular Unicellular Prokaryotes Prokaryotes Live in extreme environments Live in extreme environments Most survive only in the absence of oxygen Most survive only in the absence of oxygen No peptidoglycan No peptidoglycan Unusual lipids in cell membranes Unusual lipids in cell membranes

Domain Eukarya All organisms with a nucleus All organisms with a nucleus Some unicellular, some multicellular Some unicellular, some multicellular Some photosynthetic Some photosynthetic Some have cell walls Some have cell walls All eukaryotes All eukaryotes

Protista Most single-celled Most single-celled Few multicellular Few multicellular Some photosynthetic Some photosynthetic Others heterotrophic Others heterotrophic

Fungi Heterotrophs that feed on dead, decaying organisms Heterotrophs that feed on dead, decaying organisms Secrete enzymes into food and absorb nutrients Secrete enzymes into food and absorb nutrients Most multicellular (except yeast) Most multicellular (except yeast) Cell walls of chitin Cell walls of chitin

Plantae Multicellular Multicellular Photosynthetic Photosynthetic Autotrophs Autotrophs Cell walls of cellulose Cell walls of cellulose Range from cone-bearing plants to flowering plants to moss Range from cone-bearing plants to flowering plants to moss

Animalia Multicellular Multicellular Heterotrophs Heterotrophs NO cell walls NO cell walls Ability to move during some part of the life cycle Ability to move during some part of the life cycle