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LECTURE 5

LECTURE 5. PROKARYOTES, BACTERIA, PROTIST, Read pages 89-102. Syatematics. Systematics: Seeking Order Amidst Diversity Classification Originated as a Hierarchy of Categories Systematists Identify Features That Reveal Evolutionary Relationships Anatomy Plays a Key Role in Systematics

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LECTURE 5

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  1. LECTURE 5 PROKARYOTES, BACTERIA, PROTIST, Read pages 89-102

  2. Syatematics • Systematics: Seeking Order Amidst Diversity • Classification Originated as a Hierarchy of Categories • Systematists Identify Features That Reveal Evolutionary Relationships • Anatomy Plays a Key Role in Systematics • Microscopic structures may be used to classify organisms • Molecular Similarities Are Also Useful for Reconstructing Phylogeny

  3. Taxonomic categories • Domains • Kingdom • Phylum • Class • Order • Family • Genus • Species • The Scientific name of an organism consist of both Genus and species names

  4. What Are the Domains of Life? • The Five-Kingdom System Improved Classification • A Three-Domain System More Accurately Reflects Life’s History

  5. BACTERIA ARCHAEA EUKARYA animals fungi plants protists The tree of life

  6. FUNGI “PROTISTS” PLANTAE ANIMALIA Echinodermata (sea stars, sea urchins, sea cucumbers) Arthropoda (insects, arachnids, crustaceans) Chordata (tunicates, lancelets, vertebrates) Sarcomastigophora (zooflagellates, sarcodines) Cnidaria (hydras, anemones, jellyfish) Mollusca (snails, clams, squid) Annelida (segmented worms) Bryophyta (liverworts, mosses) Anthophyta (flowering plants) Pyrrophyta (dinoflagellates) Platyhelminthes (flatworms) Basidiomycota (club fungi) Oomycota (water molds) Euglenophyta (euglenoids) Chlorophyta (green algae) Coniferophyta (conifers) Apicomplexa (sporozoans) Phaeophyta (brown algae) Pteridophyta (ferns) Zygomycota (zygote fungi) Rhodophyta (red algae) Ascomycota (sac fungi) Ciliophora (ciliates) Porifera (sponges) the eukaryotic tree of life to Archaea to Bacteria

  7. Why Do Classifications Change? • Species Designations Change When New Information Is Discovered. • Taxonomy is dynamic

  8. Which Organisms Make Up the Prokaryotic Domains—Bacteria and Archaea? • Bacteria and Archaea Are Fundamentally Different • Classification of Prokaryotes Within Each Domain Is Difficult • Prokaryotes Differ in Shape and Structure

  9. rod-shaped archaea of the genus Methanopyrus 0.10 µm Spherical bacteria of the genus Micrococcus corkscrew-shaped bacteria of the species Leptospirosis interrogans. Three common prokaryote shapes 0.25 µm

  10. The sizes of microorganisms 1 µm Staphylococcus cyanobacterium Escherichia coli Viruses (0.05–0.2 µm) Eukaryotic cells (10–100 µm) Prokaryotic cells (0.2–10 µm) The relative sizes of eukaryotic cells, prokaryotic cells, and viruses (1 µm = 1/1000 millimeter).

  11. Domain Bacteria • Many Bacteria Form Films on Surfaces • Protective Endospores Allow Some Bacteria to Withstand Adverse Conditions • Prokaryotes Reproduce by Binary Fission • Prokaryotes May Exchange Genetic Material Without Reproducing • Prokaryotes Are Specialized for Specific Habitats • Some prokaryotes thrive in extreme conditions

  12. Reproduction in prokaryotes

  13. Conjugation: Prokaryotic “mating”

  14. Bacteria • Prokaryotes Exhibit Diverse Metabolisms • Prokaryotes Perform Functions Important to Other Organisms • Prokaryotes Capture the Nitrogen Needed by Plants • Prokaryotes Are Nature’s Recyclers • Some Bacteria Pose a Threat to Human Health • Some Anaerobic Bacteria Produce Dangerous Poisons • Humans Have Battled Bacterial Diseases Throughout History • Some Common Bacterial Species Can Be Harmful • Most Bacteria Are Harmless • Produce Antibiotics • Use in food production (from sourdough to Swiss cheese)

  15. PROTIST • Most Protists Are Single-Celled • Protists Use Diverse Modes of Reproduction and Nutrition • Protist Systematics Are in Transition • They include photosynthetic and non-photosynthetic forms (e.g. Euglena and Paramecium respectively) • Diatoms Encase Themselves Within Glassy Walls • Brown Algae Dominate in Cool Coastal Waters: multicellular protist

  16. Protistan reproduction and gene exchange Paramecium, a ciliate, reproduces asexually by cell division Euplotes, a ciliate, exchanges genetic material across a cytoplasmic bridge

  17. Brown algae, a multicellular protist

  18. flagellum eyespot Euglena contractile vacuole stored food nucleus nucleolus chloroplasts

  19. Trypanosoma,

  20. Domains Scientific Name Prokaryote Eukaryote Prokaryotic shapes Bacteria functions or effect on man and other organisms Protist Characteristics KEY WORDS

  21. LAB • Assignment 1 (p 90): • Assignment 2 (p 92): 4& 6, 7 Demo. Do 2,3 • Summary #3 is on 2. Method has been modified. • Assignment 3 (p 94): 2 & 7 Demo. Do 1,5, 10 & 11. • Assignment 4 (p 96): Do 1, 2, 3, 8 & 9. • Assignment 6 (p 98): Do 1

  22. Next Week • Fungi (pg 123-129) • Checking results of our Lab on Prokaryotes and Protists. • Review for Mid-Term Quiz.

  23. Assignment 2-a • Termites, of course, are famous as the organisms that eat wood -- often the wood in your house. However, termites could not feed on wood without the help of symbiotic protists living in their guts. These protists take in wood particles: in the picture of Trichonympha below, in the lower portion of the cell, you can see a mass of granular material that is in fact wood particles being digested. (The actual cell is about 300 microns long.) Trichonympha is only one of several such protists found in the guts of termites.

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