The protest represent an unusual mix of organisms. Protists are more diverse than all other eukaryotes and are no longer considered a single kingdomThe organisms found in this group are all eukaryotes and most are single celled for most of their life-cycle, however, some are colonial and there may even be multicellular forms.Eukaryotic differencesNucleus (with a double membrane)Organelles2 or more chromosomes (DNA + proteins)Since the protists are nutritionally diverse and can be organized into groups based on nutritional methods:AutotrophicPhotosynthesisHeterotrophicDecomposersHeterotrophicIngestion (hunters and symbiotic)MixotrophicCombining photosynthesis and ingestive or absorptive methodsThe evolution of protists is the results of endosymbiosisPrimary endosymbiosis resulted in plastid-bearing lineages which evolved into red and green algaeSecondary endosymbiosis resulted in greater diversificationKingdom Protista is now five subgroupsExcavatesMove via flagellaHave feeding grooveHeterotrophic and have modified mitochondriaGroupsDiplomonadsOne of the largest subgroupsBoth free living and symbiotic speciesHave two nucleiMultiple flagellaGiardia is an infection that comes from drinking untreated water and causes diarrheaParabasalidsOne of the largest subgroupsAnaerobicAll known species are symbiotic and some are parasiticTrichomanas Vaginalis is a sexually transmitted; males can often be asymptomaticEuglenozoansA diverse clade within the excavate linageHave distinctive mitochondriaMove via flagellaMixed nutritional methods (mixotrophic)Two Major SubgroupsEuglenidsMost are freshwaterHave 1-3 flagellaPrimarily photosynthetic but can switch to heterotrophic in the darkMany lack a rigid cell wallHave a photoreceptor call an eyespotNames after EuglenaKinetoplastidsOne flagellumSingle large mitochondrionBoth free living and symbiotic speciesSome of the symbiotic species are parasitic including Trypanosoma, causes sleeping sickness.ChromalveolatesThis is a large clade which is thought to have arisen by a secondary endosymbiosis of red algaeContain two major clades:StramenopilesHave many different forms, some living as multicellular coloniesVaried nutritional methods including mixotrophsThree major subgroupsOomycotesAlso called water moldsCells walls of celluloseCells can form aggregated coloniesFilamentous bodiesHeterotrophic decomposersDowny Mildew is one common water mold with economic importanceDiatomsMay be freshwater or marinePhotosyntheticHave glass-like “shells” known as tests with perforation to allow for exchange of substratesAbout 5600 described living species estimates 100,000 living species and more than 35000 extinct species (based on “shell” morphology.Brown AlgaeMarinePhotosyntheticDeep water to tidal“Brown” color caused by accessory pigmentsCell walls added polysaccharidesCells can form large aggregated multicellular coloniesGiant kelp forestMany have gas-bladders to keep the plant extending toward the surfaceGolden AlgaeMay be freshwater or marineall are photosynthetic but some species are mixotrophsFlagellated usually with 2 flagellaUsually unicellular but may form coloniesAlveolatesMost live as single cellsMixed nutritional methods including parasitic formsVaried forms of motilityDinoflagellatesBoth marine and freshwater2 flagella, one at the end and on in an equatorial grooveSome are photosynthetic, many are mixotrophic and many are heterotrophicMany have a cellulose cell wallMembers of this group are responsible for red tides which result in massive fish kills along the Gulf CoastApicoplexans (Sporozoans)All are heterotrophic and most are parasites which have a mobile stage called a Sporozoite.Includes:PlasmodiumCauses malariaToxoplasmaVectors through catsCiliatesMost species are solitary freshwaterHetertrophicUse cilia (short hair-like filaments that are made of protein) for movement and feedingCilia may be uniform covering of the organism or can be localized in patchesThe ciliates are the most complex of the protest with an internal structure that includes an oral groove, an anal pore, and two types of nuclei:The macronucleus handles all the day to day business and the micronucleus functions in sexual reproduction or conjugationRhizariansMost live as single cellsMost are heterotrophic but some mixotrophic species are presentMotility based on very thin pseudopodiaMay be reclassified as a clade within the chromalveolatesInclude:ForaminiferansBoth marine and freshwaterExternal multi-chambered shell known as tests composed of CaCO3Many species characterized based on shell morphologyPseudopodia extend through pores in the shellRadiolariansMainly marineInternal skeleton-like shell composed of silica (glass)Many species characterized based on shell morphologyCercozoansVery common in marine, freshwater, and even moist terrestrial ecosystemsMost are heterotrophic but also some are mixotrophic speciesMixotrophic species show how unique secondary endosymbiosisArchaeplastidsAre the closest relative of land plantsOften included as part of the land plant supergroup cladeAppears to be among the oldest eukaryotic lineagesAlso include:Red AlgaeMainly marine but some freshwater speciesCells can form large aggregated colonies which appears multicellularMainly shallow water but can occur in clear deep waterRed color caused by phycoerythrinCell wall has added polysaccharidesSome species are held upright by CaCO3Supports the deep water food webUsed in cosmetics, ice cream, paint and sushiGreen AlgaeIncludes Chlorophytes and CharophytesSome marine and many freshwater speciesUnicellular and colony formsSome species are flagelleatedHave typical chloroplastsCharophytes are the most probable ancestor of land plantsCell wall has celluloseUnikontesVery diverse super group that includes protest, fungi and animalsTwo major clades:AmoebozoansLarge diverse cladeOrganisms with lobe shaped pseudopodiaHave many different forms, some living as multicellular coloniesHeterotrophicMove using pseudopodiaFour major groups:Slime MoldsHave a mobile feeding stageA stationary reproductive stage with a fruiting body that produces sporesAcellularThey are also known as plasmodial slime molds. This name comes from the plasmodium, which is the mobile feeding stage of this organism life cycleIn the mobile stage the cells go through mitosis but not cytokinesisThe result is an acellular organism which looks like a very large multi-nucleated single “cell”This plasmodium moves through decaying
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