Classification Biology I Chapter 18

Finding Order in Diversity To study the diversity of life, biologist use a classification system to name organisms and group them in a logical manner. Taxonomy is defined as the discipline of classifying organisms and assigning each organism a universally accepted name. To avoid the confusion caused by regional or common names, biologists use a classification system to group organisms in a logical manner and to assign names.

Assigning Scientific Names The first attempts of naming were developed by Aristotle. First attempts of naming often described the physical characteristics of a species in great details. As a result names could be 20 words long! Ex: “Oak with deeply divided leaves that have no hairs on their undersides and no teeth around their edges”

Assigning Scientific Names Swedish botanist who lived during the 18 th century, Carolus Linnaeus, took a major step in developing a naming system. This is the system we use today. He develp0ed a 2-word naming system called binomial nomenclature. In binomial nomenclature, each species is assigned a two-part scientific name. Scientific names are always typed in italics. The first word is Capitalized, and the second word is lowercased.

Assigning Scientific Names The name is in Latin. The first part of the scientific name is the organism’s genus name. The genus name is Capitalized. The second part of the scientific name is the organism’s species name. This part is lowercase. Remember the name is typed in italics. Examples: Grizzly bears-Ursus arctos, Polar bears-Ursus maritimus, Giant Pandas- Ailuropoda melanoleuca

Linnaeus’s Seven Taxonomic Categories 1)Kingdom 2)Phylum 3)Class 4)Order 5)Family 6)Genus 7)Species Pneumonic to remember the levels: Keep Ponds Clean Or Fish Get Sick; Keep Praying Class Or Forget Getting Saved; King Phillip Came Over For Graduation Saturday

Classification of Living Things 1st Introduced Names of Kingdoms 1700sPlantaeAnimalia Late 1800sProtistaPlantaeAnimalia 1950sMoneraProtistaFungiPlantaeAnimalia 1990sEubacteria Archaebacteria ProtistaFungiPlantaeAnimalia This diagram shows some of the ways organisms have been classified into kingdoms over the years. The six-kingdoms system includes the following kingdoms; Eubacteria; Archaebacteria; Protista; Fungi, Plantae, and Animalia

Classification of Living Things Organisms are grouped in three domains. There is a simple relationship between the three domains and the six kingdoms The following table summarizes key evidence used in classifying organisms into these major taxonomic groups.

Classification of Living Things DOMAINBacteriaArchaeaEukarya KINGDOM EubacteriaArchaebacteriaProtistaFungiPlantaeAnimalia CELL TYPE Prokaryote Eukaryote CELL STRUCTURES Cell walls with peptidoglycan Cell walls without peptidoglycan Cell walls of cellulose in some; some have chloroplasts Cell walls of chitin Cell walls of cellulose; chloroplasts No cell walls or chloroplasts # OF CELLS Unicellular Most unicellular; some colonial; some multicellular Most multicellular ; some unicellular Multicellular MODE OF NUTRITION Autotroph or heterotroph Autotroph or hetertroph HeterotrophAutotrophHeterotroph EXAMPLES Streptococcus E. coli Methanogens Halophiles Amoeba slime mold Mushrooms yeasts Mosses Ferns flowering plants Sponges worms Insects fishes mammals