LS11 - Taxonomy Microbio STUDENT PDF

Unit 3: Taxonomy, Microscopes & Bacteria Life Sciences 11 – Ms. Hale Part I: Taxonomy Taxonomy Taxonomy – the field of biology that deals with classifying all living things Biologists have identified and named around 1.7 million species Estimated 8 million additional unknown...

Unit 3: Taxonomy, Microscopes & Bacteria Life Sciences 11 – Ms. Hale Part I: Taxonomy Taxonomy Taxonomy – the field of biology that deals with classifying all living things Biologists have identified and named around 1.7 million species Estimated 8 million additional unknown species Aristotle was the first taxonomist dividing organisms into land, sea, and air dwellers Why Classify Organisms? Organisms need a name and organization Accurately & uniformly name organisms Prevents misnomers (=wrong or inaccurate name) such as “starfish” and “jellyfish” that aren’t really fish! Uses same language (Latin) for all names Each species has only one scientific name No two different species will have the same scientific name Scientific names are recognized worldwide Shows evolutionary relationships Taxonomic Categories Linnaeus placed organisms into related groups called taxa based on their morphology (similar structure and function) There are 8 taxa within taxonomy: 1. Domain 2. Kingdom 3. Phylum 4. Class 5. Order 6. Family 7. Genus 8. Species “Dr King Phil Came Over For Good Soup” Hierarchy Classification is organized Starting from smallest to largest Each level, or taxon, groups together organisms that share more characteristics than the level before Binomial nomenclature Developed by Carolus Linnaeus (1707-1778) System of naming in which each species is assigned a two-part scientific name  Binomial nomenclature 1st part of the scientific name identifies the genus that the organism belongs to A genus is a group of closely related species 2nd part of the scientific name is unique to each species within the genus This part of the name is a general Latin description of some important characteristic of the organism or the name of an important explorer or scientist  Binomial nomenclature The scientific name is ALWAYS written in italics when typed The first letter in the first word (the GENUS) is CAPITALIZED The second word (the SPECIES) is in lowercase Example: Ursus arctos (Grizzly Bear) When handwriting it is acceptable to underline instead of italicizing Each word should be underlined separately For example: Ursus arctos (be sure to underline this in your notes!) Binomial nomenclature Examples: Panthera tigris (tiger) Panthera leo (lion) Panthera onca (jaguar) Panthera pardus (leopard) Assignment Classification Worksheet Traditional Taxonomy Linnaeus – 2 Kingdoms Animalia Plantae Then 5 Kingdom System Monera Protista Fungi Plantae Animalia  Was then split into a 6 Kingdom system Due to large differences within Kingdom Monera, it was split into two different taxa Eubacteria Archaebacteria Molecular Analysis A lot of organisms have similarities on the molecular level Indicates common ancestor These similarities are used to determine classification and evolutionary relationships Can also show how a species has evolved DNA sequence comparisons can show how different species are related The more similar the DNA sequences of two species, the more recently they have shared a common ancestor New Domain System Reflects a greater understanding of molecular and evolutionary evidence All organisms placed into 3 broad groups called domains 3 Domains of Life 1. Bacteria Peptidoglycan in cell walls Contains all other bacteria including those causing disease Unicellular & Prokaryotic 2. Archaea No peptidoglycan in cell walls Live in harsh environments 3. Eukarya Unicellular & multicellular Eukaryotic organisms Includes Kingdoms Protista, Fungi, Plantae, & Animalia 1. Kingdom Archaebacteria “Ancient” bacteria Prokaryotic Unicellular Both autotrophs & heterotrophs Has a cell wall that lacks peptidoglycan Reproduce asexually Some are motile (= can move) Live in extreme environments (Hot, Salty, Acidic) Volcanic hot springs, Salt marshes 2. Kingdom Eubacteria “Recent” bacteria Prokaryotic Unicellular Both autotrophic & heterotrophic Reproduce asexually Some are motile Cell wall has peptidoglycan (thick!) Live nearly everywhere 3. Kingdom Protista Organisms that cannot be classified as an Animal, Plant, or Fungi Least satisfying of the classifications because members display the greatest variety 3 Classifications 1. Animal-like Protists: Amoeba, Paramecium 2. Plant-like Protists: Unicellular & Multicellular; Algae 3. Fungi-like Protists: Slime molds & Water molds 3. Kingdom Protista Eukaryotic Most are unicellular, some are multicellular Autotrophs & heterotrophs Reproduce sexually & asexually Some are motile Some have a cell wall (plant-like) Live in damp or wet habitats 4. Kingdom Fungi Eukaryotic Most are multicellular (mushrooms), although some are unicellular (yeast) Heterotrophic: Absorb their food from environment. Feed on dead/decaying organic matter Have a cell wall (chitin) Reproduce sexually & asexually Non-motile Live as parasites or saprophytes nearly everywhere 5. Kingdom Plantae Eukaryotic Multicellular Photosynthetic Autotrophs Have a cell wall (cellulose) Reproduce sexually & asexually Non-motile Includes: Cone-bearing and flowering plants, mosses, & ferns. 6. Kingdom Animalia Eukaryotic Multicellular Heterotrophs Most reproduce sexually No cell walls Motile, except sponges. Very diverse Assignment Domain/Kingdom Worksheet Dichotomous Key A tool used for identifying unfamiliar organisms Is a list of observable traits that eventually lead you to the name of the organism “Dichotomous” means “divided into two parts” Therefore, dichotomous keys always have two choices in each step Question must have a yes or no answer 1a It is round ………………………………………………………….. Go to 2 1b It is not round …………………………………………………… Go to 4 2a It is orange ………………………………………………………….. BB 2b It is not orange ……………………………………………………Go to 3 3a It is big ………………………………………………………………… SB 3b It is not big …………………………………………………………..TB 4a It is grey …………………………………………………………………RB 4b It is not grey …………………………………………………………..FB Assignment! Using and Constructing a Classification Key Fun with Fictious Animals Classification Worksheet! Please complete this worksheet for the beginning of next class! Part II: Microscopes Please see handout. Part III: Bacteria Bacteria Classification General Structure (both domains)  General Structure (Both Domains) DNA – Dictates cell function Plasmid – circular DNA used specifically for sexual reproduction Ribosomes – Make proteins Cell wall – give structure to the bacterial cell Capsule – thick gelatin around the cell wall, which hardens when exposed to harsh conditions (heat/drought) protects the bacteria Pili = for movement Flagellum = some bacteria have these for movement Domain Archaea Ancient organisms, first to live on earth Live in extremely hot, salty, oxygen poor, toxic environments (hydrothermal vents, swamps, salt lakes, volcanic environments. 1. Methanogens These Archaebacteria are chemoautotrophic anaerobes. They make methane (natural gas) as a waste product. They are found in swamp sediments, sewage, and in buried landfills, guts of large mammals In the future, they could be used to produce methane as a byproduct of sewage treatment or landfill operation. 2. Halophile These are salt-loving Archaea that grow in places like the salt ponds on the edge of San Francisco Bay, or the spotted lake in BC Large numbers of certain halophiles can turn these waters a dark pink. These archaea are aerobic. 3. Thermophiles These are Archaebacteria from hot springs and other high temperature environments. Some can grow above the boiling temperature of water. They are anaerobes  Some extreme thermohalophiles grow in high temperatures such as hot sulphur springs (Sulfobus at 60-80 C) and near deep sea hot vents (105 C) Domain Bacteria (Eubacteria) Found EVERYWHERE else. Fun facts Each square centimeter of your skin averages about 100,000 bacteria. A single teaspoon of topsoil contains more than a billion (1,000,000,000) bacteria. Types of Eubacteria Bacteria can be found in different shapes Coccus (pl. cocci) Bacillus (pl. bacilli) Spirillum (pl. spirilla) (spherical shaped) (rod shaped) (spiral/corkscrew shaped)  Another morphological trait to classify bacteria is grouping Diplo- (pairs) Strepto- Staphlyo- (Filamentous - chains) (Colonial-bunches) Example: diplococci Example: Streptococci Example: Staphylococci Example: Streptobacilli Example: diplobacilli  Classification Gram staining helps classify bacteria based on the structure of the cell wall : purple stain, only have one cell layer Gram negative: pink stain, have a second, outer cell layer Gram Positive (+ve) Gram Negative (-ve) Absorb and retain the crystal Do NOT absorb crystal violet stain – PURPLE violet stain PINK COLOUR COLOUR Have 3 cell layers: The cell wall has one very An inner plasma thick peptidoglycan (sugar membrane and amino acid) layer that Thin peptidoglycan layer provides structure, shape Thick lipid layer that and strength repels the crystal violet They are more susceptible to stain antibiotics such as penicillin Gram Staining Gram Staining Gram Staining Mobility Some have one or more flagella Some lash, snake or spiral forward Some glide on a layer of slime-like material Reproduction in Bacteria Bacteria can reproduce very quickly, some divide every 20 minutes! Binary Fission When bacterium is near double in size, bacterial cell replicates its DNA and divides in half, producing two identical daughter cells. This is asexual reproduction Bacteria grow into a population Most common Sexual Reproduction in Bacteria Conjugation the transfer of “PLASMID” from one bacteria to another. in some bacterial a bridge between two individuals allows the transfer of DNA from the donor cell to the recipient cell. The plasmid will be incorporated into the DNA of new bacteria. It can contain mutations that aid the bacteria in survival This sexual reproduction provides recombination of genes for genetic diversity. Spore Formation In unfavorable growth conditions, an endospore can form the bacterium produces a thick internal wall that encloses its DNA and some of its cytoplasm. Importance of Bacteria 1. Ecological Role: Some are producers which make oxygen Some are decomposers that break down the nutrients in dead matter. Some can converting nitrogen from the air into a form plants can use (nitrogen fixation) Importance of Bacteria 2. Human uses: Foods and beverages Sewage treatment Cleaning up oil spills Synthesis of drugs and chemicals via genetic engineering Production of vitamins in human intestines 3. Pathogenic bacteria (parasites) Either directly cause damage to cells/tissues (bacterial pneumonia) or produce toxins (tetanus) Defending Against Bacterial Infections 1. Prevention Wash hands Active immunity (vaccination) Passive immunity 2. Food preservation Use heat or chemicals (salt, sugar, acids) to slow down/stop bacterial growth Includes: sterilization, refrigeration, cooking through, canning, freezing, drying 3. Antibiotics Organic compounds made by living organisms that can kill or inhibit the growth of bacteria What causes antibiotic resistance? - Kevin Wu https://www.youtube.com/watch?v=znnp-Ivj2ek