Diversity of Life: Introduction to Biological Classification By Deanne Erdmann, MS BioEd Online

Why Do We Classify Organisms? Biologists group organisms to represent similarities and proposed relationships. Classification systems change with expanding knowledge about new and well-known organisms. Tacitus bellus BioEd Online

Leucaena leucocephala Lead tree Classification Binomial Nomenclature Two part name (Genus, species) Hierarchical Classification Seven Taxonomic Catagories Systematics Study of the evolution of biological diversity BioEd Online

Carolus von Linnaeus ( ) Swedish scientist who laid the foundation for modern taxonomy Binomial Nomenclature Carolus von Linnaeus Two-word naming system Genus Noun, Capitalized, Underlined or Italicized Species Descriptive, Lower Case, Underlined or Italicized BioEd Online

Hierarchical Classification Taxonomic categories KingdomKing PhylumPhilip ClassCame OrderOver FamilyFor GenusGreen SpeciesSoup BioEd Online

Kingdoms and Domains BacteriaArchaeaEukarya BacteriaArchaeaProtistaPlantaeFungiAnimalia MoneraProtistaPlantaeFungiAnimalia The three-domain system The six-kingdom system The traditional five-kingdom system BioEd Online

Systematics: Evolutionary Classification of Organisms Systematics is the study of the evolution of biological diversity, and combines data from the following areas. Fossil record Comparative homologies Cladistics Comparative sequencing of DNA/RNA among organisms Molecular clocks BioEd Online

Taxonomic Diagrams MammalsTurtlesLizards and Snakes CrocodilesBirdsMammalsTurtlesLizards and Snakes CrocodilesBirds CladogramPhylogenetic Tree BioEd Online

Dichotomous Keys Identify Organisms Dichotomous keys versus evolutionary classification Dichotomous keys contain pairs of contrasting descriptions. After each description, the key directs the user to another pair of descriptions or identifies the organism. Example: 1.a) Is the leaf simple? Go to 2 b) Is the leaf compound? Go to 3 2.a) Are margins of the leaf jagged? Go to 4 b) Are margins of the leaf smooth? Go to 5 BioEd Online

Thank You This concludes a brief review of biological classification. You may find additional information on this section of in the expanded content talks and in the notes below each slide in the slide library. BioEd Online

By Deanne Erdmann, MS Diversity of Life: Introduction to the Organisms BioEd Online

Introduction to Phylogenetic Kingdoms Monera (Eubacteria and Archaebacteria) - Prokaryotes, with or without peptidoglycan in cell walls Protistia – Eukaryotes, diverse, not fungi, plants, or animals Fungi – Eukaryotes, multicellular (except yeasts), heterotrophic, chitin in cell walls Plantae – Eukaryotes, multicellular, non-motile, autotrophic, cell wall containing cellulose Animalia – Eukaryotes, multicellular, motile, heterotrophic, no cell wall BioEd Online

Where Do Viruses Fit? Not “alive”? Not a cell Nucleic acids in protein shell Do not grow, do not maintain homeostasis, and do not metabolize on their own Use host cell to replicate Lytic and Lysogenic life cycles Early Stage of Influenza Virus BioEd Online

Streptococcus mutans (can cause endocarditis and dental caries) Bacillus anthracis (spores can live in soil for years) The Kingdom Monera - Eubacteria Common name: Bacteria Unicellular prokaryotes No introns in genome Peptidogylcan in cell wall Basic shapes are cocci, bacilli, spirilla Diverse nutrition and respiration Reproduce by binary fission, conjugation, transformation, and transduction BioEd Online

The Kingdom Monera - Archaebacteria Cell wall does not contain peptidogylcan Cell membrane contains unusual lipids not found in other organisms Genes are interrupted by introns Classified into three groups: Methanogens—poisoned by O 2 Thermaphiles—live in extreme temps. Halophiles—live in high saline BioEd Online

Ecological Importance of Prokaryotes Decomposition Nitrogen fixation Mutualistic relationships Parasitic relationships Commercial uses Treponema pallidum, a spiral-shaped bacteria which causes Syphilis in humans BioEd Online

Entamoeba histolytica The Kingdom Protista or Protoctista A classification problem Unicellular, colonial, and multicellular forms Autotrophic and heterotrophic Some move with flagella, pseudopods or cilia Animal-like, plant-like and fungus-like groups Reproduce by mitosis and meiosis BioEd Online

Ecological Importance of Protists Important foundation in food chain Produce vast amount of O 2 Decomposition Symbiotic relationships Mutualistic Parasitic Medicinal and Industrial Uses BioEd Online Volvox Colonial green alga

Puffball Drops of rain trigger the release of spores The Kingdom Fungi Eukaryotic Cell walls contain chitin Multicellular, except for yeasts Heterotrophic Main body multicellular fungi composed of hyphae Sexual and asexual reproduction Pholiota spp Degrades wood very quickly BioEd Online

Ecological Importance of Fungi Decomposers Symbiotic Parasitic On plants On animals Mutualistic Lichens Mycorrhizae Epidermophyton floccosum, fungi causing athlete’s foot BioEd Online

The Kingdom Plantae Multicellular, non-motile, cell wall with cellulose, mostly autotrophic Plant life cycles Plant Structures relate to plant needs Sunlight, water and minerals, gas exchange, Reproduce without water to transmit male gamete (in Angiosperms) Vascular tissue, roots, stems, leaves, seeds, flowers Sunflowers in Fargo, North Dakota BioEd Online

Major Groups of Plants Three traditional groupings: Bryophytes —nonvascular plants Pteridophytes — vascular, seedless plants Seed plants Gymnosperms Angiosperms Ginkgo biloba Ginkgos are often very long-lived. Some specimens are thought to be more than 3,500 years old. BioEd Online

Importance of Plants to Humans Food source – Wheat, grains, fruits, vegetables Medicine – Aspirin, cancer treatments, stimulants Industry – Agriculture, wood products, cotton Sugercane BioEd Online

The Kingdom Animalia No cell wall Heterotrophic Motile Sexual reproduction Three distinct layers of tissues (except sponges) Multi-celled/specialized tissues and functions Distinct body plan BioEd Online

Invertebrates and Vertebrates Invertebrates 99% of the Animal Kingdom Absence of backbone Includes sponges, cnidarians, mollusks, worms, arthropods, and echinoderms Vertebrates Internal skeleton (bone or cartilage) Includes fish, amphibians, reptiles, birds, and mammals Asian ladybeetle Harmonia axyridis Notice the “false” white eye markings behind the head. BioEd Online

Colony of sponges Chambered Nautilus Invertebrate Animals I Sponges Cnidarians Worms Mollusks Arthropods Echinoderms BioEd Online

Earthworm Inquiry Activity Students list information they think they know about the earthworm Opportunity to assess prior knowledge and identify misconceptions (you should guide students to correct these during the activity) Students spend some time observing live earthworms Ask probing questions Record observations Students formulate questions they have about some of the observations they have made Students design an investigation to answer their questions Students carry out their investigation Students write reflections dealing with the entire process in their journal BioEd Online

Txodes scapularis Deer tick Invertebrate Animals II Sponges Cnidarians Worms Mollusks Arthropods Echinoderms BioEd Online

Vertebrate Animals Chordates Fish Agnatha (jawless fish/lamprey) Chondrichthyes (sharks, skates, rays) Osteichthyes (bass, tuna, salmon) Amphibians Reptiles Birds Mammals Ardea herodias Great Grey Heron BioEd Online

Thank You This concludes a survey of representative organisms in each of the kingdoms of life. BioEd Online

Introduction to Viruses By Christine Herrmann, PhD Courtesy of B.V.V. Prasad BioEd Online

What Are Viruses? Viruses are very small (10 – 400nm). not cells. a genome surrounded by a protective protein coat. infectious. dependent on a host cell to provide the machinery they need to reproduce. intracellular parasites. formed from the assembly of newly synthesized components made in a host cell. Avian influenza AH5N1 virus CDC BioEd Online

How Do Viruses Differ From Living Organisms? Viruses are not living organisms because they are incapable of carrying out all life processes. Viruses are not made of cells can not reproduce on their own do not grow or undergo division do not transform energy lack machinery for protein synthesis BioEd Online

How Were Viruses First Discovered I? In 1892, Russian scientist Dimitri Ivanowsky showed that tobacco mosaic disease was caused by an agent smaller than any known bacteria. In 1898, Dutch scientist Martinus Beijerinck realized that the agent was distinct from bacteria and termed it a virus. Tobacco Mosaic Viruses Courtesy of T. Moravec BioEd Online

How Were Viruses First Discovered II? The first animal virus, the causative agent of foot-and-mouth-disease, was discovered in 1898 by German scientists Friedrich Loeffler and Paul Frosch. Key to the discovery of plant and animal viruses was the demonstration that viruses pass through filters that retain bacteria and require a host cell to reproduce. Multiple virions of yellow fever virus, the first human virus discovered in Courtesy of CDC BioEd Online

How Are Viruses Studied? “Virology” is the study of viruses; scientists who study viruses are called virologists. Virologists use: electron microscopes to visualize viruses; cell cultures to grow viruses (although some viruses will only grow in animals) techniques from molecular biology, genetics, and immunology; proper safety precautions when studying dangerous viruses. SARS related Corona viruses Courtesy of F. Murphy, CDC BioEd Online

What Are Viruses Made Of? Viruses are composed of nucleic acid, proteins, and sometimes, lipids. Nucleic acid, which can be either DNA or RNA, encodes the genetic information to make virus copies. The nucleic acid is surrounded by a protective protein coat, called a capsid. An outer membranous layer, called an envelope, made of lipid and protein, surrounds the capsid in some viruses.. Nucleic acid Envelope Capsid BioEd Online

How Are Viruses Classified? Genetic material DNA viruses contain DNA as their genetic material. RNA viruses contain RNA as their genetic material. Capsid structure Helical (rod-shaped) Polyhedral Complex Presence or absence of a membranous envelope surrounding the capsid Helical Marburg virus Courtesy of CDC Polyhedral SV40 virus Courtesy of CDC Complex bacteriophage Courtesy of H.Ackermann BioEd Online

What Organisms and Host Cells Do Viruses Infect? Infection by viruses viruses infect bacteria, plants, animals and other living organisms in order to reproduce a given virus usually infects a limited number of species. within a host organism, usually only a limited number of cell types are susceptible to infection by a given virus Host range array of host cells that a particular virus can infect determined by a “lock-and-key” fit between the virus and a receptor on the surface of a host cell BioEd Online

How Do Viruses Reproduce? Viruses reproduce via three basic steps. 1. Viruses deliver their genomes into a host cell. 2. Viruses commandeer the host cell transcription and translation machineries and utilize host cell building blocks to copy viral genomes and synthesize viral proteins. 3. Viral genomes and proteins are self- assembled and exit host cells as new infectious particles. Details of each of these steps vary among different virus groups. Replication Transcription and Translation BioEd Online

The Lytic Reproductive Cycle of Bacteriophages Attach Inject Replicate Release Virulent Phage BioEd Online

The Lysogenic Reproductive Cycle of Bacteriophages Lytic Lysogenic Temperate Phage Prophage BioEd Online

The Reproductive Cycle of a Retrovirus—HIV Viral DNA Cell DNA Receptor Viral RNA and proteins 1. Building and entry 2. Reverse transcription 3. Integration 4. Transcription and Translation 5. Assembly and Release BioEd Online

Which Human Diseases Are Caused By Viruses? Infectious diseases DNA viruses Respiratory disease Smallpox Chicken pox Mononucleosis Cold sores Cancer RNA viruses AIDS Influenza (flu) Common cold Polio Measles BioEd Online

How Can Viral Diseases Be Prevented and Treated? Good hygiene Avoid contact with contaminated food, water, fecal material or body fluids. Wash hands frequently. Vaccines Stimulate natural defenses with in the body. Contain a component of or a weakened or killed virus particles. Are developed for many once common illnesses such as smallpox, polio, mumps, chicken pox. Not available for all viruses. Anti-viral drugs (but not antibiotics) Available for only a few viruses. Inhibit some virus development and/or relieve symptoms. BioEd Online

How Do New Viruses Emerge? Through mutation and evolution By spreading from one species to a new host species By spreading from an isolated location to more widespread locations Through the detection of previously unrecognized viruses Marburg virus Courtesy of CDC BioEd Online

Are There Infectious Agents Simpler Than Viruses? Viroids and prions are even simpler than viruses. Viroids have genetic material but no protein coat. Prions are made of protein but have no nucleic acid. Like viruses, viroids and prions are not made of cells. Viroids and prions can cause disease. BioEd Online

Introduction to Viruses - Summary Viruses are distinct from living organisms Viruses are very diverse Many important diseases that affect humans are caused by viruses New viruses are constantly emerging Development of new vaccines and ways to control viruses is important BioEd Online