Diversity of Life:

Introduction to Biological

Classification

By Deanne Erdmann, MS

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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

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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

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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

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Hierarchical Classification

Taxonomic categories Kingdom King Phylum Philip Class Came Order Over Family For Genus Green Species Soup

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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

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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

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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

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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.

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By Deanne Erdmann, MS

Diversity of Life:

Introduction

to the Organisms

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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

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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

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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

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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

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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

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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.

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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.

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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

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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.

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Introduction to Viruses

By Christine Herrmann, PhD

Courtesy of B.V.V. Prasad

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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.

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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

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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.

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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

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