Chapter 28 Protists Protists are not a monophyletic group Includes all eukaryotes that are not animals plants or fungi It contains many kingdoms Most are unicellular o But also colonial and multicellular forms Multicellular the cells are independent Colonial cells are clones they stick together share resources there is no specialization They evolved at several different times o Some are multinucleate The nucleus divides without going through cytokinesis there are many nuclei but only one cell Origin of Eukaryotes There was one common ancestor of all eukaryotes o Originated about 2 1 bya after the rise of oxygen levels o It was unicellular o Derived from archean like prokaryotes o The origin hypothesis Devolvement of an infolded internal membranes increases surface area for more metabolism assisted in water control Growth in size Serial endosymbiosis 25 9 o See 28 2 Protist Diversity Figure 28 3 Excavata All are unicellular with flagella No cell wall Diplomanads o Two haploid nuclei o Anaerobic reduced non functional mitochondria o Ex Giardia intestinalis intestinal parasite Parabasalids o Flagella and undulating membranes o Anaerobic and reduced mitochondria o Ex Trichomonas vaginalis human vaginal parasite STD Euglenozoans o Euglenids Autotroph with green chloroplasts Or heterotroph or mixotroph Ex Euglena free living o Trypanosoma One large mitochondria Flagellum in undulation membrane Ex Trypanosoma causes sleeping sickness Chromoalveolata Alveolates All unicellular All have alveoli tiny cavities under the cell surface Dinoflagellates o Heterotrophs or phytoplankton algae with extra red pigment in the chloroplasts o Have a pair of flagella in perpendicular grooves o Have cell wall of many plates with internal cellulose plates o Some blooms cause fish kills Red Tide o Some are photosynthetic mutualists with corals o Some are bioluminescent Apicomplexans o All are parasites of animals no cell walls o Complex life cycles multiple forms more than one host in life o Apical complex helps them enter the host o 1 end always penetrates the host o Ex Plasmodium Causes malaria carried by mosquitoes KNOW malaria life cycle Ciliates o Cilia for feeding and locomotion o Some are sessile and use the cilia to swirl water and bring food in o Cilia can bunch together and function almost like legs o Animal like in function no cell wall o With macronuclei and micronuclei only used in reproduction o Mostly use asexual reproduction o After about 700 cell divisions it needs to go through sexual reproduction o KNOW life cycle Stramenopiles Diatoms are unicellular phytoplankton algae with extra yellow and brown pigments o Silica walls that are glass like they look like petri dishes o Some move by squirting liquid Golden Algae o Biflagellate phytoplankton with extra yellow and brown pigments o Unicellular and colonial o Can coat themselves in glass beads Brown Algae o All are multicellular mostly marine seaweeds o Photosynthetic with brown pigments o Cell wall with align and cellulose o Ex Sargassum with floats o Ex Kelp Humans eat it Align used as a commercial food thickener Has alternation of generations 28 16 Oomycetes o Filamentous absorptive heterotrophs Superficial resemblance to fungi o But they have cell walls with cellulose not chitin o Ex water mold o Don t need to know life cycle o Ex downy mildew terrestrial plant parasite o Ex Phytophthora parasite that caused the potato famine Rhizaria Unicellular amoeboid heterotrophs feeding with threadlike pseudopodia Radiolarians o Symmetric silica skeletons o Marine phytoplankton Foraminifera forams pore bearing o Porous shells of calcium carbonate o Planktonic or sessile mostly marine o Some are visible to the naked eye o Important fossils in relative dating o 90 are extinct Archaeplastida Chloroplasts come from primary endosymbiosis Contain walls with cellulose Red Algae o Mostly marine multicellular seaweed o Photosynthetic with unique red phycoerythrin accessory pigment Helps absorb light in deep water o Some filamentous some with calcium carbonate that contribute to coral reef production o NO flagellated cells in ANY stage of life o May not appear red when not at depth o Humans eat it nori o Cell walls are a source of Carrageenan used as a thickener ice cream Agar petri dish culture Chlorophytes Green Algae o Chloroplast structure and pigments are similar to plants They are key primary producers o Known as the green algae along with charophytes o They share a common ancestor with plants o Most are fresh water many are marine o They have cellulose cell walls many are bi flagellated o Unicellular forms Plankton ex Chlamdomonas Mutualists ex Hydra o Colonial forms individual filaments Ex spirogyra Ex Volvox o Multinucleate large body form o Multicellular Freshwater algae ex Cladophora Seaweed ex Ulva edible sea lettuce Unikonta Amoebozoans o Amoeboid heterotrophs with lobe like pseudopodia o No cell walls Slime Molds o Moist terrestrial habitats rotting wood o Eat by phagocytosis o Produce stalked sport producing fruiting bodies when conditions are harsh o Plasmodial slime molds feed as a multinucleate diploid plasmodium 28 24 o Cellular slime molds feed as single cells They aggregate when food is scarce 28 25 Gymnamoebas o Free living heterotrophic feeding on bacterial protists and detritus o They are both aquatic and terrestrial o No cell wall o Ex Amoeba proteus 28 3 Entamoebas o Parasitic on vertebrates and some insects o Durable cyst form o Ex Entamoeba histolytica amoebic dysentery