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The Protists - Chapter 28

The Protists - Chapter 28. Lecture Objectives 1. Intro to “ Protists ” 2. Protist Classification - Supergroups and Clades 3. Survey of Protists. Key Characteristics 1. Eukaryotic 2. Unicellular (mostly)  often colonial, or multicellular 3. Nutritionally Diverse

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The Protists - Chapter 28

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  1. The Protists- Chapter 28 Lecture Objectives 1. Intro to “Protists” 2. Protist Classification - Supergroups and Clades 3. Survey of Protists

  2. Key Characteristics 1. Eukaryotic 2. Unicellular (mostly)  often colonial, or multicellular 3. Nutritionally Diverse • Photoautotrophs, Heterotrophs, Mixotrophs 4.Reproduction • Asexual (preferred) or Sexual 5. Worldwide distribution • Sensitive to changes in environment (water, sun, nutrients) • Rely on nutrients from ocean floor (upwelling) * being altered by humans (runoff, global warming)

  3. Key Characteristics con’t. 6. Importance • Symbionts • Dinoflagellates & coral polyps, wood-digesting in gut of termite • Plasmodium sp. (Malaria) , Phytophthora sp. (SOD, potato famine) • Producers • Along with prokaryotes  main producers in ocean* responsible for ~30% world’s photosynthesis

  4. Figure 28.29 Otherconsumers Herbivorousplankton Carnivorousplankton Protistanproducers Prokaryoticproducers

  5. Figure 28.28

  6. Protist Classification Polyphyletic group = current classification includes distantly related organisms, but does NOT include most recent common ancestors of all members • Kingdom “Protista” is no longer accepted  Grouped instead into what are called Supergroups (possible new kingdoms?) • Important to note this classification is still being sorted out and we will consider one hypothesis…….

  7. 4 Supergroups & respective clades Excavata SAR Archaeplastida Unikonta

  8. Figure 28.2 ■ Archaeplastida ■ Excavata 5 μm 20 μm 50 μm Diplomonads Parabasalids Excavata Euglenozoans Diatoms Stramenopiles Golden algae ■ “SAR” Clade ■ Unikonta 50 μm Brown algae Dinoflagellates Apicomplexans “SAR” clade Alveolates Ciliates Forams Cercozoans Rhizarians Radiolarians 100 μm Red algae Chlorophytes Greenalgae Archaeplastida Charophytes Land plants 100 μm Slime molds Amoebozoans Tubulinids Entamoebas Nucleariids Unikonta Fungi Choanoflagellates Opisthokonts Animals

  9. Supergroup Excavata:- excavated “feeding” groove - autotrophic or heterotrophic (predators) Clade: Diplomonadida Clade: Parabasala Clade Euglenozoa sub clade: Kinetoplastida sub clade: Euglenophyta

  10. SG: Excavata, Clade: Diplomonadida Anaerobic Simplified mitochondria  mitosomes 2 equal sized nuclei Multiple Flagella Ex. Giardia*Freshwater parasite in which cyst stage is consumed. Causes amoebic dysentery & killed by boiling water. Giardia sp.

  11. SG: Excavata, Clade: Parabasala Anaerobic, lack true nuclei Undulating membrane Flagella Modified mitochondria (release Hydrogen Peroxide)  change in pH  outcompete beneficial microorganisms * Infection from gene transfer with prokaryote * Ex. Trichomonas vaginalis Trichomonas vaginalis

  12. SG: Excavata, Clade Euglenozoa Flagella w/ crystalline rod Heterotrophs (predators), Autotrophic, Parasites, or Mixotrophs “Sub Clades” Kinetoplastida * Cause of Sleeping Sickness vectored by Tsetse fly * Neurological disease which is fatal if not treated Euglenophyta (see next slide) Trypanasoma sp.

  13. * Note 2 flagella Long flagellum Figure 28.8 Eyespot Lightdetector Short flagellum Contractile vacuole Nucleus Chloroplast Plasmamembrane 5 μm Pellicle: protein bands beneath PM Euglena (LM)

  14. SupergroupSARClade: Stramenopila – flagella with hair-like projections sub clade: Bacillariophyta sub clade: Phaeophyta sub clade: Chrysophyta Clade: Alveolata – Membrane bound sacs under PM sub clade: Dinoflagellata sub clade: Apicomplexa sub clade: Ciliophora Clade Rhizaria – Amoeba with thread-like pseudopodssub clade: Foraminifera sub clade: Radiolaria

  15. Figure 28.9 Hairyflagellum Smoothflagellum 5 μm Supergroup SAR, Clade Stramenopile = hairy flagella

  16. SG: SAR, Clade: Stramenopila,sub-clade: Bacillariophyta The Diatoms Unicellular algae  phytoplankton MOST abundant autotroph in oceans and lakes Silica tests that overlap Diatomaceous Earth Help reduce C

  17. SG: SAR, Clade: Stramenopila,sub-clade: Phaeophyta Brown algae (fucoxanthin) found in temperate coasts w/ cold water currents Largest, most complex algae  multicellular Tissues Thallus (holdfast, stipe, blade)  analogous to plants Waves & desiccation = cell wall with cellulose & algin Alternation of Generations Lifecycle

  18. Haploid (n) Diploid (2n) Sporangia Figure 28.13 MEIOSIS 10 cm Sporophyte(2n) Zoospore Female Developingsporophyte Gameto-phytes(n) Zygote(2n) Mature femalegametophyte(n) Male Egg FERTILIZATION Sperm

  19. SG: SAR, Clade: Stramenopila,sub-clade: Chrysophyta Golden Algae Unicellular, many colonial Bi-flagellated Fresh & marine phytoplankton, (some mixotrophs) Yellow & brown pigments = xanthophyll Microscopic & drift near surface of water Protective cysts = decades

  20. Alveoli Flagellum Figure 28.14 Alveolate 0.2 μm Supergroup SAR, Clade Alveolata = Alveoli (sacs under PM)

  21. SG: SAR, Clade: Alveolata,sub-clade: Dinoflagellata “Dinoflagellates” Marine & fresh phytoplankton Mixotrophs or heterotrophs Cellular plates of cellulose w/ grooves and 2 flagella Red Tides

  22. Flagella (a) Dinoflagellateflagella Figure 28.15 3 μm * May lead to mass mortalities (b) Red tide in the Gulfof Carpentaria innorthern Australia

  23. SG: SAR, Clade: Alveolatasub-clade: Apicomplexa Plasmodium sp. Apex on end of Merozoite Internal parasites to animals  Malaria vectored by mosquito  hides in cells where it is hidden from immune system Africa, Asia, Latin America  250 million infected, 900,000 die each year

  24. Inside human Inside mosquito Merozoite Sporozoites(n) Liver Livercell Figure 28.16 Apex Oocyst MEIOSIS Red bloodcell 0.5 μm Merozoite(n) Redbloodcells Zygote(2n) FERTILIZATION Gametes Game-tocytes(n) Haploid (n) Diploid (2n)

  25. SG: SAR, Clade: Alveolata,sub-clade: Ciliophora Paramecium sp. “Ciliates” Cilia for locomotion & feeding Macro & micro nuclei (sex) Binary fission Found in all waters Predators or Parasitic

  26. Contractilevacuole Figure 28.17a Oral groove Cell mouth Cilia 50 μm Micronucleus Food vacuoles Macronucleus (a) Feeding, waste removal, and water balance.

  27. Compatiblemates Conjugation Asexualreproduction MEIOSIS Figure 28.17b-2 Haploidmicronucleus Diploid micronucleus Diploid micronucleus The original macro-nucleus disintegrates. MICRO-NUCLEARFUSION (b) Conjugation and reproduction.

  28. SG: SAR, Clade: Rhizaria,sub-clade: Foraminifera Marine, fresh water Attached to sand, rocks, algae Porous, multi-chambered shells (CaCO3) = tests Pseudopods extend through pores * Phagocytosis Many have endosymbiotic algae Mg content = temp changes Make sedimentary rocks

  29. SG: SAR, Clade: Rhizaria,sub-clade: Radiolarians Delicate, symmetrical skeletons made of silica Pseudopods radiate from central body  engulf via phagocytosis

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