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Kingdom PROTISTA: What are protists?

Kingdom PROTISTA: What are protists?. Domain Eukarya Eukaryotes have a Nucleus and many organelles! Defined by exclusion – Cannot be classified as plants, animals or fungi Diverse in body, obtaining food, and movement. How did eukaryotes evolve?. Probably evolved 2 billion years ago

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Kingdom PROTISTA: What are protists?

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  1. Kingdom PROTISTA: What are protists? • Domain Eukarya • Eukaryotes have a Nucleus and many organelles! • Defined by exclusion – Cannot be classified as plants, animals or fungi • Diverse in body, obtaining food, and movement

  2. How did eukaryotes evolve? • Probably evolved 2 billion years ago • Arose through endosymbiosis • One organism lives inside another organism • Photosynthetic prokaryote lived inside another prokaryote chloroplast • Aerobic prokaryote lived inside another prokaryote mitochondrion • cDNA and mDNA is similar to Bacteria DNA

  3. How did eukaryotes evolve?

  4. PROTISTA characteristics: body plans • Most are unicellular (example, Paramecium) • Some small multicellular colonies (example, Volvox) • Some large multicellular colonies (example, kelp) paramecium volvox kelp

  5. PROTISTA characteristics: obtaining food Some protists are autotrophs • Absorb energy of sun through pigments • Make their own food through photosynthesis light energy + 6H20 + 6CO2 C6 H1206 + 6O2

  6. PROTISTA characteristics: obtaining food Other protists are heterotrophs • Get their food by eating other organisms • Release energy by cellular respiration C6 H1206 + 6O2 6H20 + 6CO2 + energy(ATP)

  7. PROTISTA characteristics: motility • Some move with long, whip-like flagella • Others move with shorter cilia • Others move by extended pseudopodia pseudopodia flagella cilia

  8. PROTISTA asexual reproduction • Most protists reproduce asexually • Binary fission  1 cell divides into 2 equal size cells • Multiple fission  1 cell divides into more than 2 • How do the offspring compare? • Offspring are genetically identical to parent • Similarity is created by the process of mitosis

  9. PROTISTA sexual reproduction • Some protists can reproduce sexually • Protist conjugation  2 cells join, exchange DNA • How do the offspring compare? • Resultingoffspring are genetically unique • Uniqueness is created by the process of meiosis

  10. Animal-like PROTISTA • Move like animals • Heterotrophic: obtain food like animals • NOT closely evolutionarily linked to animals

  11. Animal-like PROTISTAPhylum Protozoa • Body plan: unicellular • Motility: form pseudopodia • Heterotrophic: absorb food by endocytosis pseudopod

  12. Animal-like PROTISTAPhylum Protozoa

  13. Animal-like PROTISTAPhylum Ciliophora • Body plan: unicellular • Motility: cilia beat in waves • Heterotrophic: cilia sweep food into mouth cilia

  14. Animal-like PROTISTAPhylum Sarcomastigophora • Body plan: unicellular • Motility: one or more flagella • Heterotrophic or parasitic • Some cause disease • Trypanosoma causes sleeping sickness • Giardia contaminates water

  15. Fly takes up blood and injects trypanosomes Epimastigotes reproduce by mitosis in the salivary gland and transform → trypanosomes Trypanosomes enter bloodstream Trypanosomes reproduce by mitosis in blood and spinal fluid Promastigotes leave the fly gut and transform → epimastigotes Fly takes up blood and trypanosomes In fly gut, trypanosomes transform → promastigotes and reproduce by mitosis Trypanosomes spread in circulatory and nervous systems

  16. Animal-like PROTISTAPhylum Apicomplexa • Body plan: unicellular • Motility: no means of locomotion • All are parasitic • Some cause disease • Plasmodium causes malaria • Cryptosporidium contaminates water

  17. Oocysts grow, rupture, release sporozoites Mosquito takes up blood and injects sporozoites Schizonts transform →merozoites.Liver cells rupture Sporozoites invade liver cells Sporozoites transform → schizonts Ookinete invades mosquito gut, transforms → oocyst Mosquito takes in ♂ and ♀ gametocytes Asexual route: merozoites → schizonts → merozoites → blood cells rupture Merozoites invade blood cells Zygote transforms → ookinete Sexual route: some merozoites transform → gametocytes In mosquito stomach, ♂ gamete penetrates ♀ gamete→ zygote

  18. Fungus-like PROTISTA Often called molds but NOT in Kingdom Fungi • Protist cell walls are composed of cellulose • Fungi cell walls are composed of chitin

  19. Fungus-like PROTISTAPhylum Myxomycota (plasmodial slime molds) • Body plan: unicellular or multicellular • Mobile and stationary life stages

  20. Fungus-like PROTISTAPhylum Myxomycota (plasmodial slime molds) • Mobile stage of life cycle • Forms plasmodium: mass of cytoplasm • Creeps by amoeboid-like streaming • Consumes decaying plants by endocytosis

  21. Fungus-like PROTISTAPhylum Myxomycota (plasmodial slime molds) Stationary stage of life cycle • Reproduces when food is scarce • Forms sporophores: spore-bearing structures

  22. Fungus-like PROTISTAPhylum Oomycota (water molds) • Body plan: unicellular and multicellular • Motility: flagella • Parasitize fish and many crop plants

  23. Plant-like PROTISTA • Autotrophic: obtain food like plants • Lack true roots, stems, and leaves

  24. Plant-like PROTISTAFour basic body plans

  25. Plant-like PROTISTATypes of pigments • Chlorophyll absorbs red and blue light • Other pigments absorb other wavelengths • √ Efficient photosynthesis

  26. Pigments Chlorophyll – green Phycobilin – blue-green, yellow, and red Fucoxanthin – brown and olive-green Carotenoid – red, orange, and yellow

  27. Plant-like PROTISTAPhylum Chlorophyta (green algae) • Diverse body forms: all four • Diverse habitats: aquatic, moist terrestrial, symbiotic relationships • Pigments: chlorophyll and carotenoids • Share common ancestor with plants? (same pigments and cell wall composition)

  28. Plant-like PROTISTAPhylum Phaeophyta (brown algae) • Body form: multicellular • Pigments: chlorophyll and fucoxanthin • Habitat: cold, nutrient-rich, rocky coasts • Some of the largest algae known

  29. Plant-like PROTISTAPhylum Rhodophyta (red algae) • Body form: multicellular • Pigments: chlorophyll and phycobilin • Phycobilin can absorb deep-penetrating light • Rhodophyta can live at great depths

  30. Plant-like PROTISTAPhylum Bacillariophyta (diatoms) • Body form: unicellular or colonial • Pigments: chlorophyll, carotenoids, fucoxanthin • 2-piece shells have radial or bilateral symmetry • Important role as producers in food web

  31. Plant-like PROTISTAPhylum Dinoflagelleta (dinoflagellates) • Body form: unicellular • Pigments: chlorophyll and carotenoids • Some species produce a red tide • Turn water reddish during population explosion • Red tide toxin can kill large numbers of fish

  32. Plant-like PROTISTAPhylum Chrysophyta (golden algae) • Body form: unicellular and colonial • Pigments: chlorophyll, carotenoids, fucoxanthin • Resistant cysts allow survival beneath frozen lakes in winter and dry lakes in summer • Store surplus energy as oil

  33. Plant-like PROTISTAPhylum Euglenophyta (euglenoids) • Body form: unicellular • Pigments: chlorophyll, carotenoids • Autotrophic (photosynthetic) and heterotrophic (eyespot and flagellum)

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