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Diversity of Life: Introduction to Biological Classification By Deanne Erdmann, MS BioEd Online.
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Transcript of Diversity of Life: Introduction to Biological Classification By Deanne Erdmann, MS BioEd Online.
Diversity of Life:
Introduction to Biological
Classification
By Deanne Erdmann, MS
BioEd Online
www.BioEdOnline.org
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
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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
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Carolus von Linnaeus(1707-1778)
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
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Hierarchical Classification
Taxonomic categories Kingdom King Phylum Philip Class Came Order Over Family For Genus Green Species Soup
BioEd Online
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Kingdoms and Domains
Bacteria Archaea Eukarya
Bacteria Archaea Protista Plantae Fungi Animalia
Monera Protista Plantae Fungi Animalia
The three-domain system
The six-kingdom system
The traditional five-kingdom system
BioEd Online
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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
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Taxonomic Diagrams
Mammals Turtles Lizards and Snakes
Crocodiles Birds Mammals Turtles Lizards and Snakes
Crocodiles Birds
CladogramPhylogeneticTree
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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 4b) Are margins of the leaf smooth? Go to 5
BioEd Online
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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
www.BioEdOnline.org
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
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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
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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
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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 O2
Thermaphiles—live in extreme temps. Halophiles—live in high saline
BioEd Online
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Ecological Importance of Prokaryotes
Decomposition Nitrogen fixation Mutualistic relationships Parasitic relationships Commercial uses
Treponema pallidum,
a spiral-shaped bacteria which
causes Syphilis in humans
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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
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Ecological Importance of Protists
Important foundation in food chain
Produce vast amount of O2
Decomposition Symbiotic relationships
Mutualistic Parasitic
Medicinal and Industrial Uses
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VolvoxColonial green alga
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PuffballDrops 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
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Ecological Importance of Fungi
Decomposers Symbiotic
Parasitic On plants On animals
Mutualistic Lichens Mycorrhizae
Epidermophyton floccosum,
fungi causing athlete’s foot
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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
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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
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Importance of Plants to Humans
Food source – Wheat, grains, fruits, vegetables
Medicine – Aspirin, cancer treatments, stimulants
Industry – Agriculture, wood products, cotton
Sugercane
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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
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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
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Colony of sponges
Chambered Nautilus
Invertebrate Animals I
Sponges Cnidarians Worms Mollusks Arthropods Echinoderms
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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
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Txodes scapularisDeer tick
Invertebrate Animals II
Sponges Cnidarians Worms Mollusks Arthropods Echinoderms
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Vertebrate Animals
Chordates Fish
Agnatha (jawless fish/lamprey) Chondrichthyes (sharks, skates, rays) Osteichthyes (bass, tuna, salmon)
Amphibians Reptiles Birds Mammals
Ardea herodiasGreat Grey Heron
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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
www.BioEdOnline.org
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 virusCDC
BioEd Online
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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
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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 VirusesCourtesy of T. Moravec
BioEd Online
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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
1901.
Courtesy of CDC
BioEd Online
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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 virusesCourtesy of F. Murphy, CDC
BioEd Online
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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
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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 virusCourtesy of CDC
Polyhedral SV40 virusCourtesy of CDC
Complex bacteriophageCourtesy of H.Ackermann
BioEd Online
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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
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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
1
2
3
BioEd Online
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The Lytic Reproductive Cycle of Bacteriophages
Attach
Inject
Replicate
Release
Virulent Phage
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The Lysogenic Reproductive Cycle of Bacteriophages
Lytic Lysogenic
Temperate Phage
Prophage
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The Reproductive Cycle of a Retrovirus—HIV
Viral DNA
CellDNA
Receptor
Viral RNA and proteins
1.Building
andentry
2.Reverse
transcription
3.Integration
4.Transcription
andTranslation
5. Assembly
andRelease
BioEd Online
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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
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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
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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 virusCourtesy of CDC
BioEd Online
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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
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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