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Classification Chapter 18 2006-2007 What is Classification? • System to organize ALL living things into groups with biological meaning. • Taxonomy: The study of classification. Assigning a Name Problem: Common names can vary among languages. Common name is misleading. Descriptions are too long to be a name. ex: Mountain Lion or Puma or Cougar ex: Starfish, dragonfly ex:“Oak with deeply divided leaves that have no hairs on their undersides and no teeth around their edges.” Solution: Latinized and Greek words are commonly used to avoid any language issues. Reduce the number of words to a two part name. Carolus Linnaeus • The Linnean system where each species has a 2 part (scientific) name: BIONOMIAL NOMENCLATURE • genus • Species (Genus is 1st word, species is 2nd) Homo sapiens • means “wise man” • perhaps in a show of hope & optimism Genus groupings • Classify organisms into broader groups • Species that are closely related are grouped into the same genus – Leopard Panthera pardus – African lion Panthera leo – Tiger Panthera tigris Classification System • Linnaeus’ hierarchical system: Taxons Kingdom Phylum Class Order Family Genus Species general specific (Kings play chess on fine gold squares) Kingdoms and Domains Modern groups are six kingdoms: Eubacteria, Archaebacteria, Protista, Fungi, Plantae, Animalia Domains – newest, largest inclusive category developed from comparing r-RNA subunits. Bacteria, Archaea, Eukarya So…, classification sequence is now: D, K, P, C, O, F, G, S Cladogram comparing Domains Eukaryote Classification 6 Kingdom system Prokaryote Prokaryotes No separate organelles in their cells Bacteria Archaebacteria Eukaryotes Separate organelles in their cells Protists Plants Fungi Animals Regents Biology Bacteria & Archaebacteria Figure 18-12 Key Characteristics of Kingdoms and Domains Taxon Characteristics Section 18-3 Classification of Living Things DOMAIN Bacteria Archaea KINGDOM Eubacteria Archaebacteria CELL TYPE Eukarya Protista Fungi Plantae Animalia Prokaryote Prokaryote Eukaryote Eukaryote Eukaryote Eukaryote 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 Unicellular Unicellular Most unicellular; some colonial; some multicellular Most multicellular; some unicellular Multicellular Multicellular MODE OF NUTRITION Autotroph or heterotroph Autotroph or heterotroph Autotroph or heterotroph Heterotroph Autotroph Heterotroph EXAMPLES Streptococcus, Escherichia coli Methanogens, halophiles Amoeba, Paramecium, slime molds, giant kelp Mushrooms, yeasts Mosses, ferns, flowering plants Sponges, worms, insects, fishes, mammals CELL STRUCTURES NUMBER OF CELLS Organizing systems Making sense out of the differences Eastern gray squirrel Regents Sciurus Biology carolinensis Organizing the world of organsims The Tree of Life organize creatures by structure & function how they are built how they live organize them into groups of closely related creatures Regents Biology Modern Classification • Just using appearance is not enough. • New system uses: 1. Fossils 2. Dissections/comparative anatomy 3. Molecular similarities/DNA/enzymes 4. Evolutionary similarities or developmental milestones Ex: amniotic sac, jaws, endothermic Cladistics • Classifying organisms according to the order that they diverged from a common ancestor. 1. Ancestral characters – found in all groups 2. Derived characters – found in some groups ex: backbone is an ancestral trait found in all birds and mammals ex: hair is a derived trait found in only mammals Vertebrate Cladogram What are the Derived Traits in this cladogram? What could the ancestral trait be? Which organisms share the trait of claws/nails? Which organism doesn’t have any of the traits? Which organisms are more closely related? - Perch and pigeon - Pigeon and chimp