Reminder: Eukaryotes have a nucleus and other membrane-bound organelles, such as mitochondria and chloroplasts Copyright © 2004 by Pearson Education, Inc.

* Protista is an informal term to refer to the eukaryotes that do not belong in the Animalia, Plantae, or Fungi kingdoms * A very diverse group, some have traits similar to those of animals, while some are like plants and others are like fungi. And some are like all three! * Most are unicellular but some are multicellular (like some algaes) * Lack specialized tissues that would group them within the animal, plant, or fungi kingdoms * Example: algae lack the vascular tissues characteristic of the plants * Found everywhere there is water

Barton, et al., Evolution, Cold Spring Harbor Laboratory Press, 2007

Campbell, et al., Biology, Pearson, 2008

* Some have an ‘excavated’ groove on one side of the cell body * Excavates include protists with modified mitochondria and others with unique flagella * Three main groups: * Diplomonads * Parabasalids * Euglenozoans

* Lack plastids (organelle that makes chemical compounds) * Have mitosomes (reduced mitochondria) * Have two nuclei and multiple flagella * Most found in anaerobic environments * Many are parasites * Giardia intestinalis Campbell, et al., Biology, Pearson, 2008

* Also have reduced mitochondria called hydrogenosomes (hydrogen gas as a byproduct) * Also lack plastids * Most found in anaerobic environments * Trichonmonas vaginalis

* Very diverse group that includes heterotrpohs, photosynthetic autotrophs, and parasites * All have a spiral or crystalline rod inside the flagella (unknown function) Campbell, et al., Biology, Pearson, 2008

* Kinetoplastids * Single large mitochondrion containing an organized mass of DNA called a kinetoplast * Trypanosoma sp. The Parasite Museum, www.parasitemuseum.com

* Brain-Eating Amoebas!!! * Not really an Amoeba, it’s an Amoeba-flagellate * Naegleria fowleri * Lives in warm freshwaters but has also been found in soil and low-chlorinated pools * Invades the central nervous system via the nose where it does extensive damage * It then travels up nerve fibers into the brain where it begins to eat the brain piece by piece * Survival is less than 1% * : 121 deaths in U.S * 2007: 12 year-old boy and 22 year-old man die at Lake LBJ * 2010: 7 year-old boy dies near Glen Rose (10 th case in Texas since 2000) sters-inside-me-the-brain-eating- amoeba.html

* Euglenids * Have a pocket at one end of the cell from which two flagella emerge * Many are ‘mixotrophs’ in that they can swith from autotrophic to heterotrophic to adapt to changes in their environment * Euglena sp

* Large, extremely diverse group of protists * Includes some of the most important photosynthetic organisms on Earth as well as some very well known pathogens * Two main groups: * Alveolates * Stramenopiles

* Alveolates * Have membrane- bounded sacs (alveoli) just under the plasma membrane (unknown function) * Includes three subgroups: * Dinoflagellates * Apicomplexans * Ciliates Mona Hoppenrath, http://tolweb.org

* Dinoflagellates * Cells reinforced by cellulose plates * Two flagella located in perpendicular grooves * Greek dinos= whirling * Abundant components of both marine and freshwater plankton Dave Hill,

* Dinoflagellates * Red tide: dinoflagellate bloom caused by high nutrients * Toxins produced by some have caused massive kills of invertebrates and fishes

* Dinoflagellates * Zooxanthellae * Live in a symbiotic relationship with organisms like coral * Photosynthetic autotrophs that provide the host with sugars Scott R. Santos, Auburn University

* Dinoflagellates * Zooxanthellae Eric Yao, 2011

* Apicomplexans * Nearly all are parasites * Most have intricate life cycles requiring two or more host species * Plasmodium sp. (malaria) The American Society for Clinical Investigation, 2011

* Ciliates * Large, varied group * Use cilia to move and feed * Have two types of nuclei: tiny micronuclei and large macronuclei * Usually reproduce asexually by binary fission * Very common in freshwater, some in saltwater * Paramecium sp. Power And Syred / Science Photo Library, 2011

* Stramenopiles * Group of marine algae * Characteristic flagellum has numerous fine, hairlike projections * Usually paired with a shorter, smooth flagellum * Four groups: * Diatoms * Golden algae * Brown algae * Oomycetes Power And Syred /

* Diatoms * Unicellular algae * Unique glass-like wall made of silica * Major component of freshwater and marine plankton * Massive accumulations of fossilized diatoms make diatomaceous earth Wikimedia commons, 2009

* Golden Algae * Golden because they have yellow and brown pigments * Most unicellular, some colonial * Typically biflagellated * Component of freshwater and marine plankton 2006 Olympus BioScapes Digital Imaging Competition,

* Brown Algae * Largest and most complex of the algae * Multicellular * Most marine * Common in cooler water * A ‘seaweed’ * Kombu used in japanese soups * Algin, substance from the cell wall, is used to thicken many processed foods: pudding, ice cream, salad dressing, etc.

* Brown Algae * Thallus:algae body that is plant-like * Stipe: like a stem but no vascular tissue * Holdfast: like roots but just an anchor * Blade:like leaves but without vascular tissues Campbell, et al., Biology, Pearson, 2008

* Oomycetes * Water molds * Used to be classified as fungi * Oomycete= ‘egg fungus’ * Many have filaments that resemble fungal hyphae * Cell walls made of cellulose * Decomposers or parasites

* Supergroup Rhizaria * Grouped based on molecular similarities not morphology (form and structures) * All have Pseudopodia: extensions that bulge from cell surface * Includes 3 groups: * Forams * Radiolarians * Chlorarachniophytes

* Foraminiferans (Forams) * Latin * foramen: little hole * Tests: porus shell made of calcium carbonate * Pseudopodia extend through the pores function in feeding, test formation, and feeding * Most photoautotrophic (symbiotic zooxanthellae) * Most are benthic but some planktonic