Taxonomy

Taxonomy Definition: The study of classification Why group things? Easier to find information about an organism Easier to identify an organism Shows evolutionary relationships Historical Background Aristotle - (350 B.C.) First scientist to group organisms as either plants or animals

What does “binomial nomenclature” mean? Carolus Linnaeus (Karl Linne 1701-1778) - “Father of Modern Taxonomy” Grouped things according to structural similarities Developed a “Binomial Nomenclature” system for identifying every organism What does “binomial nomenclature” mean? 2 term naming system

Binomial Nomenclature Rules Names are in Latin Why? First name is the Genus, the second name is the species Genus is Capitalized and species is not Both names are either italicized or underlined (e.g. Canis familiarus and Homo sapien) Because Latin is a dead language and is not subject to change. Cougar. Mountain lion, puma are all common names for same species Felis concolor

Classification Categories (taxa) Different levels from the most general characteristics to more specific characteristics Eight levels of taxonomy are: Domain Eukarya Kingdom Animalia Phylum Chordata Class Mammalia Order Primata Family Homideae Genus Homo Species sapien

Modern Evolutionary Taxonomy We still look at structural similarities, but we also look at: Homologous structures - suggests common ancestor

Developmental stages - from embryo to adult; the more similar the stages, the closer they are taxonomically

What is the closest living terrestrial relative of the whale? Biochemical Similarities – compare DNA or RNA sequences of different organisms to determine ancestry and taxonomic relationship The more similar the sequences, the more recently they shared a common ancestor What is the closest living terrestrial relative of the whale? Hippo. Yeast cells and humans share the gene that codes for myosin (muscles in humans and moving internal cell parts in yeast). American (turkey) vulture and stork are genetically more similar than vultures are to each other

Molecular clocks – scientists compare accumulated neutral mutations (markers) of closely related species to estimate the length of time they have been evolving independently DRAW FIG. 18-9, pg. 455 Like a family tree

Tiny free-swimming larva Structural Similarities Cladograms Diagram that helps scientists understand how organisms evolved in relation to each other and when new traits appeared Lines represent evolutionary descent and show common ancestors Crustaceans Gastropod Crab Barnacle Limpet Molted exoskeleton Segmentation Tiny free-swimming larva Structural Similarities CLADOGRAM

Three Domains (developed in 1990) Archaea- Kingdom Archaebacteria Bacteria- Kingdom Eubacteria Eukarya- Kingdoms Protista, Fungi, Plantae and Animalia Six Kingdoms Kingdom Archaebacteria (archae =“ancient”) Prokaroytes, no nucleus, unicellular, autotroph or heterotroph, cell walls without peptidoglycan e.g. Thermophiles, halophiles, acidophiles Peptidoglycan, also known as murein, is a polymer consisting of sugars and amino acids that forms a homogeneous layer outside the plasma membrane of eubacteria

e.g. Streptococcus and E. coli, (“germs”) Kingdom Eubacteria Prokaroytes, no nucleus, unicellular, autotroph or heterotroph, cell walls with peptidoglycan e.g. Streptococcus and E. coli, (“germs”) Kingdom Protista Simple, many are unicellular, no specialization of tissues Protozoans Algae

e.g. mushrooms, molds and yeast Kingdom Fungi Multicellular organisms (except yeast) that have a cell wall and absorb food through the cell wall. e.g. mushrooms, molds and yeast Kingdom Plantae Multicellular organisms, contain chlorophyll, have organs and tissues, autotrophs Kingdom Animalia Multicellular organisms, heterotrophs, have organs and tissues

Classification Movie