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PROTISTS

Learn about the fascinating world of protists, which are unicellular eukaryotic organisms with over 115,000 known species. Discover the different classes of protists, including animal-like and plant-like protists, and explore examples such as ciliates, amoebas, euglena, diatoms, and more.

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PROTISTS

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  1. PROTISTS

  2. Protists • Protists: Unicellular eukaryotic organisms. • Over 115,000 species • Eukaryotic cells - contain membrane-bound organelles (particularly mitichondria & chloroplasts) • Protists & eukaryotes probably evolved from a large eukaryotic cell ingesting a photosynthetic and oxygen metabolizing bacteria • Known as endosymbiotic theory • Two major classes of protists • Animal-like protists • Plant-like protists

  3. Animal-like Protists • Phylum Ciliophora (Cilia bearing protists) • Aka "ciliates" • Have cilia (short hairlike structures) on their plasma membranes • Cilia rapidly beat and provide propulsion for the protist. • Over 7000 species in this phylum. • Example is paramecium.

  4. Paramecium • Large organisms ~305 micrometers long • Important features: • Have 2 nuclei • Macronucleus (large) • Micronucleus (smaller) • Feed by forcing H2O into Gullet forming foodvacuoles • Excrete wastes through anal pore • Excrete excess water through use of contractile vacuoles • Move by coordinated movement of hair-like cilia.

  5. More Paramecium

  6. Phylum Sporozoa • Usually parasitic in nature • Example is Plasmodia which causes malaria. • One of the most deadly diseases to man • Malaria is transmitted by the Anopheles mosquito.

  7. Lifecycle of Plasmodia

  8. Phylum SarcodinaProtists with false feet • Use extensions of cytoplasm to move and feed. • Extensions are called pseudopods (false feet) • Movement is by extending pseudopod, then the remainder of cytoplasm flows into extension. • Feeding is done by extending 2 pseudopods around object and engulfing object, forming a food vacuole • Examples are amoebas (amebas)

  9. Amoebas

  10. More amoebas

  11. Plant-like Protists • 5 phyla of plant-like protists • Are usually photosynthetic, and also heterotrophic. • All are unicellular, most are motile • Example: Phylum Euglenophyta

  12. Phylum Euglenophyta • Example is euglena. • Has a flagellum, is motile • Is both heterotrophic & autotrophic • Contains chloroplasts & is photosynthetic. • Can become heterotrophic in low-light conditions

  13. Euglena

  14. Dinoflagellates • Have 2 flagella for motility • Often have a cellulose covering

  15. Diatoms • Most abundant form of marine algae. • Form elaborate silicon (glass) shells to protect themselves • Shell is porous to allow materials in/out of the cell.

  16. Multicellular / Other Algae • Are not generally true multicellular organisms, but rather "colonies" • Show beginnings of specialized functions / tissues • 3 types • Green algae • Red Algae • Brown algae

  17. Green algae (Chlorophyta) • Green algae (Chlorophyta) • Contain chlorophyl a & b • Most frequently found in fresh water • Often colonial Volvox: a green colonial algae

  18. Red Algae (Rhodophyta) • Red Algae (Rhodophyta) • Found in salt/brackish water • Have additional pigments which give them a reddish color. • In uncontrolled blooms, these organisms can cause serious ecological damage Red algeal bloom

  19. Brown Algae (Rhodophyta) • Brown Algae (Rhodophyta) • Most Plant-like of all algae. • Include kelps • Can grow to huge sizes (100') • Most primitive plant like organism to show alternation of generations. Giant Kelp Forest

  20. Fungus like Protists: • Fungus like Protists: • Act as decomposers • Often have a slimy appearance/texture, hence their name. • 3 types: • Plasmodial slime molds • Cellular slime molds • Water molds

  21. Plasmodial Slime Molds • Plasmodial Slime Molds • Can grow very large, however, is still a single cell (with many nuclei) • Feeding stage is called a plasmodium. • Forms fruiting bodies under stress.

  22. Cellular Slime Molds: • Cellular Slime Molds: • Exists a majority of its life cycle as an amoeba • In  times of stress these amoebas unite to form a Pseudoplasmodium, which crawls to another location (slug form), and forms a fruiting body

  23. Water molds: • Water molds: • Completely aquatic • Often decomposers • Sometimes parasitic Water mold attacking a fish

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