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Classification Chapter 17 1 Species of Organisms •Almost 2 million species of organisms have been described •Thousands more are discovered each year •The total number of species ranges from 5 to 30 million 2 What is Classification? Classification is the arrangement of organisms into orderly groups based on their similarities Classification is also known as taxonomy Taxonomists are scientists that identify & name organisms 3 Benefits of Classifying •organisms Accurately & uniformly names •starfish Prevents misnomers such as & jellyfish that aren't really fish Uses same language (Latin or some Greek) for all names • Sea”horse”?? 4 Confusion in Using Different Languages for Names 5 Latin Names are Understood by all Taxonomists 6 Early Taxonomists •2000 years ago, Aristotle was the first taxonomist Aristotle divided organisms into plants & animals He subdivided them by their habitat -- • • Ex) land, sea, or air dwellers 7 Carolus Linnaeus 1707 – 1778 • 18th century taxonomist • Classified organisms by • • their form and structure Developed 7 levels of classification Developed naming system still used today 8 Carolus Linnaeus •Called the “Father of Taxonomy” •Developed the modern system of naming known as binomial nomenclaturetwo-word name (Genus & species) 9 Standardized Naming Binomial nomenclature uses: Genus species Latin or Greek Italicized in print Capitalize genus, but NOT species Underline when writing • • • • • Turdus migratorius American Robin 10 Binomial Nomenclature 11 Classification Groups • Taxon ( taxa-plural) is a • • category into which related organisms are placed There is a hierarchy of groups (taxa) from broadest to most specific Domain, Kingdom, Phylum, Class, Order, Family, Genus, species 12 Hierarchy-Taxonomic Groups BROADEST TAXON Domain Kingdom Phylum Class Order Family Genus Species 13 King Phillip Came Over For Good Spaghetti! 14 15 Two Modern Systems Six Kingdom System Three Domain System 16 The Six Kingdoms: 17 KingdomArchaebacteria •The prefix archae - comes from the Greek word "ANCIENT" •Unicellular & Prokaryotic •Some are autotrophic and some are heterotrophic •Live in extreme environments Sewage treatment plants, thermal vents, etc. 18 Kingdom Eubacteria •Cause human diseases, are present in almost all habitats on earth •Many bacteria are important environmentally and commercially. Live in the intestines of animals 19 Kingdom Protista “The odds and ends kingdom” Dumping ground of organisms that don’t fit into the other kingdoms Eukaryotic Unicellular or Multicellular Ex) Algae, Slime molds, Diatoms, and Protozoa 20 Kingdom Fungi • Multicellular, except yeast • Absorptive • heterotrophs (digest food outside their body & then absorb it) Decomposers Ex) yeast, mold, mildew, & mushrooms 21 Kingdom Plantae •Multicellular •Autotrophic •Absorb sunlight to make glucose – Photosynthesis Cell walls made of cellulose • 22 Kingdom Animalia • Multicellular • Ingestive • heterotrophs (consume food & digest it inside their bodies) Feed on plants or animals 23 24 Domains • Broadest, most inclusive taxon Three domains: 1.Archaea 2.Eubacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles) 3.Eukarya are more complex and have a nucleus and membranebound organelles 25 Domain Eukarya includes: •Protista (protozoans, algae…) •Fungi (mushrooms, yeasts …) •Plantae (multicellular plants) •Animalia (multicellular animals) 26 27 Skills Practice 1. List the levels of classification from most broad to most specific. 2. What type of organisms are found in the kingdom Archaebacteria? Are these organisms unicellular or multicellular? 3. What 4 kingdoms are in the Domain Eukarya? 4. What is the difference between an autotroph and a heterotroph? Give an example of each. 28 Classification is based on evolutionary relationships: • Homologous structures (same structure, different function) • Similar embryo development • Similarity in DNA, RNA, or amino acid sequence of Proteins 29 Homologous Structures show Similarities in mammals. 30 Similarities in Vertebrate Embryos 31 • Phylogenetics- the analysis of the evolutionary or ancestral relationships among a taxon (group). • Phylogenetic diagram (tree)- a branching tree that indicates how closely related species are. 32 33 34 Cladogram Diagram showing how organisms are related based on shared, derived characteristics such as feathers, hair, or scales 35 Primate Cladogram 36 Let’s Create A Cladogram from the following: Derived Characters segmented jaws hair placenta multicellular limbs kangaroo + + + - + + earthworm + - - - + - amoeba - - - - - - lizard + + - - + + cat + + + + + + sponge - - - - + - salmon + + - - + - 37 Dichotomous Keying •Used to identify organisms •Characteristics given in pairs •Read both characteristics and either go to another set of characteristics OR identify the organism 38 Example of Dichotomous Key 1a 1b 2a 2b 3a 3b 4a 4b Tentacles present – Go to 2 Tentacles absent – Go to 3 Eight Tentacles – Octopus More than 8 tentacles – 3 Tentacles hang down – go to 4 Tentacles upright–Sea Anemone Balloon-shaped body–Jellyfish Body NOT balloon-shaped - 5 39 40