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 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)

Dinoflagellates & coral polyps, wood-digesting in gut of termite 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

Prokaryotic producers Other consumers Herbivorous plankton Carnivorous plankton Figure 28.29 Protists: key producers in aquatic communities Prokaryotic producers Protistan producers Figure 28.29

Figure 28.28 Sudden oak death

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…….

4 Supergroups & respective clades Excavata SAR Archaeplastida Unikonta

■ Excavata ■ Archaeplastida ■ “SAR” Clade ■ Unikonta 5 μm 20 μm 50 μm Diplomonads Parabasalids Excavata Euglenozoans Diatoms Stramenopiles Golden algae ■ “SAR” Clade Brown algae 50 μm ■ Unikonta Dinoflagellates Apicomplexans Alveolates “SAR” clade Ciliates Forams Cercozoans Rhizarians Radiolarians 100 μm Red algae Green algae Chlorophytes Charophytes Archaeplastida Giardia intestinalis, a diplomonad parasite Globigerina, a rhizarian in the SAR clade Land plants 100 μm Slime molds Amoebozoans Tubulinids Entamoebas Nucleariids Unikonta Fungi Opisthokonts Choanoflagellates Animals Figure 28.2

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

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.

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

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) Trypanosomes evade immune responses by switching surface proteins  host cannot develop immunity Trypanasoma sp.

* Note 2 flagella Long flagellum Eyespot Light detector Figure 28.8 * Note 2 flagella Long flagellum Eyespot Light detector Short flagellum Contractile vacuole Nucleus Figure 28.8 Euglena, a euglenid commonly found in pond water Chloroplast Plasma membrane 5 μm Pellicle: protein bands beneath PM Euglena (LM)

Supergroup SAR Clade: 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 pseudopods sub clade: Foraminifera sub clade: Radiolaria

Supergroup SAR, Clade Stramenopile = hairy flagella Figure 28.9 Hairy flagellum Smooth flagellum Figure 28.9 Stramenopile flagella 5 μm Supergroup SAR, Clade Stramenopile = hairy flagella

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

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

Developing sporophyte Gameto- phytes (n) Figure 28.13 Haploid (n) Diploid (2n) Sporangia MEIOSIS 10 cm Sporophyte (2n) Zoospore Female Developing sporophyte Gameto- phytes (n) Figure 28.13 The life cycle of the brown alga Laminaria: an example of alternation of generations Zygote (2n) Mature female gametophyte (n) Egg Male FERTILIZATION Sperm

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

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

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

* May lead to mass mortalities Figure 28.15 Flagella (a) Dinoflagellate flagella 3 μm * May lead to mass mortalities Figure 28.15 Dinoflagellates (b) Red tide in the Gulf of Carpentaria in northern Australia

SG: SAR, Clade: Alveolata sub-clade: Apicomplexa 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 Plasmodium sp.

Inside mosquito Inside human Merozoite Sporozoites (n) Liver Figure 28.16 Inside mosquito Inside human Merozoite Sporozoites (n) Liver Liver cell Apex Oocyst MEIOSIS Red blood cell Merozoite (n) 0.5 μm Red blood cells Zygote (2n) Figure 28.16 The two-host life cycle of Plasmodium, the apicomplexan that causes malaria Plasmodium requires both mosquitoes and humans to complete its life cycle Approximately 900,000 people die each year from malaria FERTILIZATION Gametes Game- tocytes (n) Haploid (n) Diploid (2n)

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

(a) Feeding, waste removal, and water balance. Figure 28.17a Contractile vacuole Oral groove Cell mouth Cilia 50 μm Micronucleus Food vacuoles Macronucleus Figure 28.17a Structure and function in the ciliate Paramecium caudatum (part 1) (a) Feeding, waste removal, and water balance.

The original macro- nucleus disintegrates. Diploid micronucleus Figure 28.17b-2 Compatible mates Conjugation Asexual reproduction MEIOSIS Haploid micronucleus Diploid micronucleus The original macro- nucleus disintegrates. Diploid micronucleus MICRO- NUCLEAR FUSION Figure 28.17b-2 Structure and function in the ciliate Paramecium caudatum (part 2, step 2) (b) Conjugation and reproduction.

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

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