1 / 36

Exploring Protists: The First Eukaryotes

Delve into the diverse world of Protists, the first eukaryotes, including their categorization, general features, and species examples. Learn about protozoa, algae, endosymbiosis, and their ecological roles. Discover fascinating organisms like Euglena, Giardia, and Diatoms.

fredericka-kelley
Download Presentation

Exploring Protists: The First Eukaryotes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Protists Chapter 28

  2. In the beginning… • van Leeuwenhoek when observing protozoa: • “no more pleasant site has met my eye than this” (1681) • “My excrement being so thin I was…persuaded to examine it. I have sometimes seen animalcules a-moving very prettily…” (a bad week in 1681)

  3. Understanding the Protista • For this class we will focus on: • How they are categorized • General features of protozoa • Exceptions to the general features • Examples of sexual reproduction • Specific species from several, not all, clades of protists (good reason to attend lecture)

  4. Protista

  5. Protists – the first eukaryotes • Protozoa • Algae (unicellular and colonial) • Algae (large – seaweeds, kelp) • Diatoms • Water molds

  6. A model for the formation of eukaryotic cells: Endosymbiosis

  7. A model for diversity in Protists: Endosymbiosis again

  8. Protists – the first eukaryotes • Greater cellular complexity than in prokaryotes • The most nutritionally diverse of all eukaryotes • Photoautotrophs • Heterotrophs • Mixotrophs • Ecology • Protozoa (ingestive, animal-like) • Fungus-like (absorptive) • Algae (photosynthetic, plant-like) Golden algae

  9. General Features • Unicellular and multicellular • Colonial and true multicellular • Free-living and parasitic • Most complex unicellular organism • Sexual and asexual reproduction

  10. Euglena: autotrophs but can become heterotrophic (mixotrophs)

  11. A sampling of protists Giardia Euglena Amoeba Trypanosoma

  12. A sampling of protists Diatoms, algae – primary productivity in aquatic and marine systems Unicellular Colonial Multicellular

  13. A sampling of protists Red Algae Kelp Golden Alga Nori (red alga)

  14. Diplomonads and Parabasalids • Giardia intestinalis • Water borne parasite • Common in backcountry • Anaerobes • Harm host by mechanical blockage of gut • Trichomonas vaginalis • Sexually-transmitted parasite • Outcompetes in disturbed area • Can acquire helpful gene from bacteria • Males asymptomatic

  15. Euglenozoans – just listen • Kinetoplastids – Trypanosomes • Cause sleeping sickness (Africa), Chagas disease (Central and S. America) • Antigenic variation in surface proteins • 1/3 of genome codes for surface antigens

  16. Alveolates • Dinoflagellates • Phytoplankton • Can cause “red tide” • Toxins can sicken or kill humans Pfiesteria shumwayae

  17. Alveolates • Apicomplexans • Parasitic • Complex life cycle • Cause of malaria • Know this life cycle!

  18. Malaria • Sporozoites infect liver cells • Merozoites burst from liver • Infect RBC’s, eat and reproduce in cycle • Gametocytes produced • Mosquito takes a meal • Zygote moves to hemocoel • Produces sporozoites • Injected into next victim

  19. Stramenopiles – just listen • Oomycetes – water molds • Look at your dead goldfish • Diatoms – unicellular algae with silica wall • Diatomaceous earth • Golden algae

  20. Stramenopiles • Brown algae • Seaweed • Complex multicellular • Seaweed body is a thallus with: • Rootlike holdfast • Stemlike stipe • Leaflike blades

  21. Alternation of generations

  22. Amoebozoans • Entamoebas • All in genus Entamoeba are parasitic • E. histolytica (“tissue lysis”) • Causes amoebic dysentery (bloody diarrhea) • 100,000 deaths worldwide/yr

  23. Amoebozoans • Slime molds, 2 kinds: • Plasmodial • Forms a unicellular, multinucleate mass (plasmodium) • Cellular • Individual amoebas come together to form a multicellular organism

  24. Red and Green Algae • Red algae • Similar to seaweeds (brown algae) • Green algae • Uni- and multicellular • Colonial types (Volvox) • Symbionts with fungi (lichens) • Close relatives to land plants

  25. Chlamydomonas nivalis “green” algae

More Related