Biological Classification Chapter 17 Objective: K3 - Define taxonomy, recognize the importance of a standardized taxonomic system to the scientific community, & use a dichotomous key to classify an organism

Finding Order in Diversity To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner. Taxonomy - the branch of biology that groups and names organisms based on studies of their different characteristics Biologists who study taxonomy are called taxonomists. Tacitus bellus Classification systems change with expanding knowledge. Populus tremuloides Quaking Aspen

Carolus Linnaeus Swedish botanist Developed Binomial Nomenclature - (Two-word naming system) - Genus »Noun, Capitalized, Underlined or Italicized - Species »Descriptive, Lower Case, Underlined or Italicized – Each species is assigned a two-part scientific name Exp. Ursus arctos Carolus von Linnaeus ( ) Scientist who laid foundation for modern taxonomy

System of Classification Linnaeus’s hierarchical system of classification includes seven levels (from largest to smallest) Grizzly Bear (common name) –Kingdom Animalia –Phylum Chordata –Class Mammalia –Order Carnivora –Family Ursidae –Genus Ursus –Species arctos Each of the levels is called a TAXON Ursus arctos (scientific name)

Taxonomic categoriespneumonic device –KingdomKing –PhylumPhilip –ClassCame –OrderOver –FamilyFor –GenusGood –SpeciesSoup System of Classification

Dichotomous Keys Identify Organisms Dichotomous keys contain pairs of contrasting descriptions. After each description, the key directs the user to another pair of descriptions or identifies the organism. Example: 1.a) Is the leaf simple? Go to 2 b) Is the leaf compound? Go to 3 2.a) Are margins of the leaf jagged? Go to 4 b) Are margins of the leaf smooth? Go to 5 3. a) Leaflets attached at one central point? Buckeye b) Leaflets attached at several points? Go to 7

Kingdoms and Domains Domain –Most inclusive category –Larger than a kingdom –There are 3 »Eukarya – includes the kingdoms Protists, Fungi, Plants & Animals »Bacteria – corresponds to the kingdom Eubacteria »Archaea – corresponds to the kingdom Archaebacteria

Kingdom Fungi Cell Type: Eukaryotic – most Multicellular / some Unicellular (yeast) Structure: all have cell walls made of chitin Obtain nutrients: Heterotrophs (by absorption) – external digestion; breaks down dead or decaying matter Examples: Mushrooms, Mold, Yeast

Streptococcus mutans (can cause endocarditis and dental caries) Bacillus anthracis (spores can live in soil for years) The Kingdom Eubacteria Common name: Bacteria Cell Type: Prokaryotic - Unicellular Structure: All have cell wall with Peptidogylcan Obtain nutrients: autotroph or heterotroph Basic shapes are cocci, bacilli, spirilla Reproduce by binary fission Examples: E. coli, streptococcus, staphylococcus, lactobacillus

The Kingdom Archaebacteria Cell Type: Prokaryotic - Unicellular Structure: All contin cell wall without peptidogylcan Obtain nutrients: autotroph or heterotroph Examples: Methanogens—poisoned by O 2 Thermaphiles—live in extreme temperatures Halophiles—live in high saline

Entamoeba histolytica The Kingdom Protista A classification problem Cell Type: Eukaryotic –Unicellular or Multicellular Structure: Some have cell walls, some move with flagella, pseudopods or cilia Obtain nutrients: Autotrophic (plant-like) and heterotrophic (animal-like) Examples: Amoeba, paramecium, diatom, euglena

The Kingdom Plantae Cell Type: Eukaryotic – Multicellular Structure: cell wall with cellulose Obtain nutrients: Autotrophs (by the process of photosynthesis which makes glucose) Examples: Flowers, trees, grass Sunflowers in Fargo, North Dakota Ginkgo biloba Ginkgos are often very long-lived. Some specimens are thought to be more than 3,500 years old.

Colony of sponges Kingdom Animalia Cell Type: Eukaryotic – Multicellular Structure: no cell walls Obtain nutrients: Heterotrophic (by ingestion – must eat) Examples: Sponges, reptiles, mammals Txodes scapularis Deer tick

Domain Kingdom Phylum Class Order Family Genus Species

Six Kingdoms