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Animal-Like Protists

Animal-Like Protists. Heterotrophic Classified by means of locomotion : flagella, cilia, pseudopods , or none (sessile) Many free living, some parasites of humans and animals. Paramecium (many species) is free living. Animal-Like Protists Phylum Protozoa.

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Animal-Like Protists

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  1. Animal-Like Protists • Heterotrophic • Classified by means of locomotion: flagella, cilia, pseudopods, or none (sessile) • Many free living, some parasites of humans and animals Paramecium (many species) is free living

  2. Animal-Like ProtistsPhylum Protozoa • Locomotion by pseudopodia cytoplasmic streaming/cyclosis amoeboid movement • Prey on bacteria, ingest food particles in water using pseudopodia  vesicle, intracellular digestion • Subphylum Sarcodina - amoebas: freshwater, marine or soil; some have a test/shell around cell membrane • Subphylum Mycetozoa – some have glassy shells (radiolarians)

  3. Testate Amoebas Simple tests (or shells) are made by either secretion or by the agglutination of foreign material or a combination of both. Environmental changes can be determined by analyzing the composition of tests, including fossil tests, which may indicate past climatic conditions.

  4. Radiolarian (marine amoeba) shells

  5. Animal-Like ProtistsPhylum Ciliophora • Locomotion by cilia • Asexual reproduction – binary fission • Most elaborate organelles of any protist: • Macronucleus that controls cell functions • Micronucleus exchanged through conjugation (sexual reproduction) • pellicle (elastic layer of protein) surrouding cell membrane • Food acquisition: oral groove  mouth pore  gullet  food vacuoles • Excretion: anal pore  contractile vacuole

  6. Trypanosomes in human blood Animal-Like ProtistsPhylum Sarcomastigophora • One or more flagella • Subphylum Mastigophora– many free living, some parasites  genus Trypanosoma • Infect blood in many vertebrates • Transmitted by insect vectorsEx.: African sleeping sickness, caused by two species of trypanosomes, transmitted by tse-tse fly fever, lethargy, eventual coma, death;Giardia – found in fresh water  gastrointestinal disease Tsetse fly (vector)

  7. Giardialamblia causes giardiasis, an intestinal infection Found in freshwater – streams & rivers Cysts carried in animal feces

  8. Animal-Like ProtistsPhylum Apicomplexa (former sporozoans) • no adaptations for locomotion  all animal parasites • Apical complex = organelles specialized for entry into host cells/tissues • Complex life cyles with sexual and asexual stages, often more than one host • Plasmodium – mosquito vector  malaria • Toxoplasmagondii – affects developing fetuses, newborns • Cryptosporidium – found in water, animal feces  gastrointestinal disease Plasmodium faciparum

  9. Anopheles mosquito vector Malaria life cycle on UTube Malaria 350–500 million cases / year, killing one to three million people

  10. Fungus-Like ProtistsSlime Molds & Water Molds • Uni- or multi-cellular, all heterotrophic • Saprophytic, some parasitic

  11. Fungus-Like ProtistsPhylum Myxomycota – Plasmodial Slime Molds • Feeding stage = Plasmodium, a multinucleated (2n) mass of cytoplasm • Amoeboid movement by cytoplasmic streaming • phagocytosis of decaying matter • Reproductivestate = Fruitingbodies produce haploid spores by meiosis • Spores produce haploid (n) reproductive cells that fuse (2n) • mitosis w/o cytokinesis  multinucleated plasmodium (unicellular)

  12. Physarum life cycle

  13. Fungus-Like ProtistsPhylum Dictyostelida – Cellular Slime Molds • Individual haploid cells live independently • Scarcity of food triggers release of chemical that attract others • Many cells gather to form a multi-cellular pseudoplasmodium– (each cell retains its membrane)  develops fruiting bodies  haploid spores  new independent haploid cells

  14. How do cellular slime molds differ from plasmodial slime molds?

  15. Fungus-Like ProtistsPhylum Oomycota – Water Molds • Asexual reproduction -- flagellated zoospores  threadlike cells • Sexual reproduction – egg and sperm produced  fertilization tubes  zygote  threadlike cells Water mold on dead mayfly larva

  16. Healthy Tasmanian frog Fungus-Like ProtistsPhylum Chytridiomycota – Water Molds • Most unicellular, parasitic • Make flagellatedgametes and zoospores • Chitin in cell walls, filamentous cells, enzymes and biochemistry similar to fungi • some classify them in kingdom Fungi • may be a transitional form between protists and fungi Infected frog Chytrid (microscopic)

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