Classification A. Why classify? 1. Organize in a meaningful way Too many living things to talk about without organization 2. Universal naming All scientists everywhere use the one same name. For example: The humu-humu-nuku-nuku-apua a is the Hawaiian state fish. But this common name refers to 2 different fish: Rhinecanthus rectangulus, also called the reef trigger fish or the rectangular trigger fish, and Rhinecanthus aculeatus, or Picasso trigger fish. Plus, the nickname of humu-humu refers to these and many other trigger fish. (The official state fish of Hawaii is R. rectangulus.) 3. Show relationships, evolutionary trends A good system changes based on new data 1
B. Modern Evolutionary Classification Phylogeny - evolutionary relationships among organisms Now organisms are classified, based on their evolutionary history Cladogram - diagram that shows evolutionary relationships among organisms Derived characters - traits that are in recent species, but not older members of the lineage Similarities in DNA & RNA used to determine classification & evolutionary relationships. Molecular clocks - using DNA comparisons to estimate the length of time two species have been evolving independently. C. Seven Taxa Kingdom Phylum Class Order Family Genus Species Animalia Animalia Animalia Chordata Chordata Chordata Mammalia Mammalia Mammalia Carnivora Carnivora Carnivora Felidae Felidae Canidae Panthera Lynx Canis Panthera leo Lynx rufus Canis rufus Lion Bobcat Red Wolf 2
*List the 7 Taxa! (Do you have a mnemonic device?) Kingdom Phylum Class Order Family Genus Species Animalia Animalia Animalia Chordata Chordata Chordata Mammalia Mammalia Mammalia Carnivora Carnivora Carnivora Felidae Felidae Canidae Panthera Lynx Canis Panthera leo Lynx rufus Canis rufus *Explain how closely two organisms are related. *Explain how the taxa are related. *What is the largest taxon? What is the smallest taxon? D. Species Organisms which look alike and can breed in nature to produce fertile offspring. *Binomial Nomenclature = scientific name for species Carl Linneaus tried to give all species in the natural world a two part name (1700 s) *Rules: 1. Two words (modern scientific Latin) 1st - Genus 2nd - Specific descriptor 2. First letter of the first word ONLY, is capitalized 3. Both words underlined separately (type set in italics) 3
Practice 1. What is wrong with each of the 3 names below? 2. Try writing your first and last name as if it were a species name - use the rules of binomial nomenclature. Example: Jane Smith could be written as Jane smith or Smith jane Which is better and why? (Smith is a general group, Jane describes the individual in that group.) More Practice What is the scientific name for the monarch butterfly? Here is more information than you need G - danaus C - insecta K - animalia F - danaidae O - lepidoptera P - arthropoda Specific descriptor - plexippus The capital letters stand for the taxa starting with that letter (K = kingdom). Use the rules! (Did you get Danaus plexippus?) 4
E. The Three Domains Eukarya All eukaryotes - whose cells have a nucleus and membrane-bound organelles (animals, plants, fungi, protists) Bacteria Eubacteria - means true bacteria (common bacteria) Archaea Archaebacteria - means ancient bacteria (extremophiles) F. The Six Kingdoms Eubacteria Archaebacteria Protista Plantae Fungi Animalia Cell Type Number of cells Mode of Nutrition Cell Wall? Prokaryotic Uni- cellular Autotroph or heterotroph Yes - with peptidoglycan Prokaryotic Uni- cellular Autotroph or heterotroph Yes - no peptidoglycan Eukaryotic Unicellular (most) Autotroph or heterotroph Some - with cellulose Eukaryotic Multicellular Autotroph Yes - with cellulose Eukaryotic Multi- Cellular (most) Hetero- troph: absorptive Yes - with chitin Eukaryotic Multicellular Hetero- troph: ingestive No Streptococcus E. coli Methanogens, halophiles Amoeba, Paramecium, Volvox Moss, fern, grass, rose, elm, cycad Mushroom, yeast Sponge, ant, worm, fish, dog, human 5
According to this cladogram (based on molecular genetics), what kingdom is Animalia most related to? G. Using a Key 1. Dichotomous - two choices at each line 2. Always start at the first line & choose between 1a and 1b 3. Follow directions until you reach the name (Try the last fastener!) 1a. With a hole Go to Question 2 1b. Without a hole Go to Question 3 2a. Six sided Hexnut 2b. Four sided Square nut 3a. With threading Go to Question 4 3b. Without threading Nail 4a. Pointy tip Go to Question 5 4b. No pointy tip Go to Question 6 5a. Rounded head Sheetmetal screw 5b. Not rounded head Wood screw 6a. Flat head Go to Question 7 6b. Not flat head Machine screw 7a. Body length twice the width of head Long bolt 7b. Body length not twice the width of head Short bolt 6
To MAKE the key: first start with a dichotomous diagram 1a. With a hole Go to Question 2 1b. Without a hole Go to Question 3 2a. Six sided Hexnut 2b. Four sided Square nut 3a. With threading Go to Question 4 3b. Without threading Nail 4a. Pointy tip Go to Question 5 4b. No pointy tip Go to Question 6 5a. Rounded head Sheetmetal screw 5b. Not rounded head Wood screw 6a. Flat head Go to Question 7 6b. Not flat head Machine screw 7a. Body length twice the width of head Long bolt 7b. Body length not twice the width of head Short bolt Lichens - symbiotic pairing between algae and fungi, or fungi and cyanobacteria How many different kingdoms here? 7
clover May apple arrowhead Flowers trillium violet bellwort 8