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The Protists

The Protists. Eukaryotes. Most unicellular. Most aerobic. Moist environments Can be photoheterotrophs, photoautotrophs, chemoheterotrophs or mixotrophs. Flagella or cilia. All protists can reproduce asexually, some sexually. Endosymbiosis.

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The Protists

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  1. The Protists • Eukaryotes. • Most unicellular. • Most aerobic. • Moist environments • Can be photoheterotrophs, photoautotrophs, chemoheterotrophs or mixotrophs. • Flagella or cilia. • All protists can reproduce asexually, some sexually

  2. Endosymbiosis • Eukaryotic cells evolved from symbiotic combinations of prokaryotic cells. • Mitochondria aerobic heterotrophic prokaryotic cells • Chloroplasts photosynthetic prokaryotes

  3. Evidence for Endosymbiosis Similarities between modern bacteria and the chloroplasts/mitochondria of eukaryotes: *size *enzymes *circular DNA molecules *process of division *ribosomes similar

  4. The Candidate Kingdoms • Archaezoa • Euglenozoa • Alveolata • Stramenopila • Rhodophyta • Green Algae

  5. Candidate Kingdom Archaezoa • Giardia • have two nuclei, flagella, and no mitochondria (…parasites)

  6. Candidate Kingdom Euglenozoa Autotrophic and/or heterotrophic flagellates • Euglena • 1 or 2 flagella • Kinetoplasts parasitic, e.g. African Sleeping Sickness (bite of tsetse fly) Trypanosoma

  7. Candidate Kingdom Alveolata • Dinoflagellates, phytoplankton, cause red tides, color from xanthophyll. • Apicomplexans, plasmodium, causes malaria. • Ciliates, paramecium Next Group

  8. Dinoflagellates http://www.microscopy-uk.org.uk/mag/artsep01/dinof.html http://www.microscopy-uk.org.uk/mag/indexmag.html

  9. Apicomplexans Leishmania Parasite infected erythrocyte

  10. Life history of Plasmodium

  11. Ciliates Stentor Paramecium Vorticella

  12. Pseudopod “Protists”Taxonomic lineage unclear, so no clear kingdom found… i.e. “misfits” • Rhizopods, amoebas • Actinopods, radiolarians and heliozoans (delicate silica shells). • Foraminiferans, marine with porous calcium shells. Used as index fossils. • Slime Molds, cytoplasmic streaming

  13. Rhizopod Amoeba

  14. Actinopods Radiolarians

  15. Foraminiferans

  16. Slime Molds • Plasmodial Slime Mold – Myxomycota. Heterotrophic,brightly colored, multinucleated ameboid mass.

  17. Candidate Kingdom Stramenopila • Diatoms (bacillariophyta)– unicellular plankton with box-like silica walls. Diatomaceous earth. • Golden Algae(chrysophyta) – yellow and brown carotene and xanthophyll pigments • Brown Algae(phaeophyta)- largests and most complex. Seaweeds and kelps, may be as long as 60m. • Water Molds(oomycota) – white rusts and downy mildews Next Group

  18. Diatoms

  19. Golden Algae - Chrysophyta

  20. Brown Algae - Phaeophyta Kelp Harvesting

  21. Kelp Structures • Analogous plant-like structures • Body = thallus • Root-like structure – holdfast • Stem-like structure – stipe • Leaf-like structure - blades

  22. Water molds, white rusts and downy mildews Water mold White rust on spinach

  23. Candidate Kingdom Rhodophyta • Red color from pigment • Marine • Multicellular • Carrageenan thickener

  24. Candidate Kingdom Green Algae *Many scientists advocate inclusion of green algae into the plant kingdom. *More than 7000 species, mostly freshwater. *Unicellular – Chlamydomonas *Colonial – Volvox *Multicellular – Ulva Ulva

  25. Green Algae - Chlorophyta Volvox Chlamydomonas Spirogyra

  26. Chlamydomonas Life Cycle

  27. Ulva Life Cycle

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