protist apbio
TRANSCRIPT
Chapter 20Chapter 20
The Diversity of ProtistsThe Diversity of Protists
Chapter 20Kingdom Protista:Kingdom Protista:CharacteristicsCharacteristics
Mostly unicellular, eukaryotic cellsMostly unicellular, eukaryotic cellsReproduce asexually or sexually by conjugationReproduce asexually or sexually by conjugationExhibit all three modes of nutritionExhibit all three modes of nutrition• PhotosynthesisPhotosynthesis• IngestionIngestion• AbsorptionAbsorption
Ultimately spawned all multicellular kingdomsUltimately spawned all multicellular kingdomsVery diverse kingdomVery diverse kingdomDifficult for taxonomists to agree on Difficult for taxonomists to agree on
classificationclassification
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Diverse Modes of NutritionDiverse Modes of Nutrition
Use diverse modes of nutritionUse diverse modes of nutrition• Ingest foodIngest food• Absorb nutrients from surroundingsAbsorb nutrients from surroundings• PhotosynthesisPhotosynthesis
Protists that ingest food are typically Protists that ingest food are typically predatorspredators
Use extensions of cell membrane called Use extensions of cell membrane called psuedopodspsuedopods to surround and engulf prey to surround and engulf prey itemitem
Chapter 20
Chapter 20
Diverse Modes of NutritionDiverse Modes of Nutrition
Protists that absorb nutrients directly Protists that absorb nutrients directly from the surrounding environment can from the surrounding environment can bebe• Free-livingFree-living types in the soil that types in the soil that
decompose organic dead matterdecompose organic dead matter• ParasitesParasites that live inside the bodies of that live inside the bodies of
other organisms, sometimes harming the other organisms, sometimes harming the host host
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Diverse Modes of NutritionDiverse Modes of Nutrition
Some protists have photosynthetic Some protists have photosynthetic organelles called chloroplastsorganelles called chloroplasts
Photosynthetic protists are abundant in Photosynthetic protists are abundant in oceans, lakes, and pondsoceans, lakes, and ponds• Free floatingFree floating•Mutually beneficial associations with Mutually beneficial associations with
other organisms: solar energy captured other organisms: solar energy captured by the protist is used by host, which by the protist is used by host, which shelters and protects the protist shelters and protects the protist
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Diverse Modes of NutritionDiverse Modes of Nutrition
Photosynthetic protists are collectively Photosynthetic protists are collectively known as known as algaealgae
Single-celled, non-photosynthetic Single-celled, non-photosynthetic protists are collectively known as protists are collectively known as protozoaprotozoa
Chapter 20
Diverse Modes of ReproductionDiverse Modes of Reproduction
Most protists reproduce asexually by Most protists reproduce asexually by mitotic cell divisionmitotic cell division
Some also reproduce sexuallySome also reproduce sexually• Two individuals contribute genetic material Two individuals contribute genetic material
to an offspring that is genetically different to an offspring that is genetically different from either parentfrom either parent• Occurs during certain time of year or Occurs during certain time of year or
circumstances (e.g. a crowded environment circumstances (e.g. a crowded environment or a food shortage) or a food shortage)
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Protist ReproductionProtist Reproduction
Asexual Sexual(a)(a)(a)(a) (b)(b)(b)(b)
Chapter 20
Effects on HumansEffects on Humans
Positive impact - ecological role of Positive impact - ecological role of photosynthetic marine protists (algae)photosynthetic marine protists (algae)• capture solar energy and make it available to capture solar energy and make it available to
the other organisms in the ecosystem the other organisms in the ecosystem • release oxygen gas release oxygen gas
Negative impact - many human and plant Negative impact - many human and plant diseases are caused by parasitic protists diseases are caused by parasitic protists
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Major Groups of ProtistsMajor Groups of Protists
Protist classification is in transitionProtist classification is in transitionGenetic comparison reveals Genetic comparison reveals evolutionary history of organismsevolutionary history of organisms
Genetic, instead of physical features Genetic, instead of physical features now separate protist species into now separate protist species into different lineagesdifferent lineages
Some physically dissimilar species are Some physically dissimilar species are now placed in a common lineagenow placed in a common lineage
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Chapter 20
Chapter 20
The ExcovatesThe Excovates
Lack mitochondriaLack mitochondriaTwo major groupsTwo major groups• Diplomonads: Diplomonads: have two nuclei and move have two nuclei and move
about by means of multiple flagella about by means of multiple flagella • Parabasalids: Parabasalids: live inside animalslive inside animals
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ParabasalidsParabasalids
Mutually beneficial relationships with Mutually beneficial relationships with other speciesother species• Parabasalid inhabits gut of termite Parabasalid inhabits gut of termite • Termite delivers food to parabasalid, Termite delivers food to parabasalid,
which digests and releases nutrients to which digests and releases nutrients to termitetermite
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ParabasalidsParabasalids
Harms host speciesHarms host species• Trichomonas vaginalisTrichomonas vaginalis causes the causes the
sexually transmitted disease sexually transmitted disease trichomoniasistrichomoniasis• TrichomonasTrichomonas inhabits urinary and inhabits urinary and
reproductive tracts, using flagella to reproductive tracts, using flagella to move through themmove through them• Causes vaginal itching and discharge in Causes vaginal itching and discharge in
females females
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Chapter 20
The EuglenozoansThe Euglenozoans
Have distinctive mitochondriaHave distinctive mitochondriaTwo major groupsTwo major groups• Euglenids Euglenids • KinetoplastidsKinetoplastids
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EuglenidsEuglenids
Single-celled, fresh-water protistsSingle-celled, fresh-water protistsLack a rigid outer coveringLack a rigid outer coveringBest known example is Best known example is EuglenaEuglena•Moves by whipping single flagellumMoves by whipping single flagellum• PhotosyntheticPhotosynthetic
Some euglenids photosynthetic, others Some euglenids photosynthetic, others absorb/engulf foodabsorb/engulf food
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EuglenidsEuglenids
Photoreceptor (eyespot) found in some Photoreceptor (eyespot) found in some euglenoidseuglenoids• Provides for a way to sense location of Provides for a way to sense location of
light sourcelight source• Useful for photosynthetic euglenoids in Useful for photosynthetic euglenoids in
maximizing photosynthesismaximizing photosynthesis
Chapter 20EuglenaEuglena::a Representative Euglenoida Representative Euglenoid
FlagellumFlagellumFlagellumFlagellumEye SpotEye SpotEye SpotEye Spot
ContractileContractileVacuoleVacuole
ContractileContractileVacuoleVacuole
Stored FoodStored FoodStored FoodStored Food
NucleusNucleusNucleusNucleus
NucleolusNucleolusNucleolusNucleolus
ChloroplastsChloroplastsChloroplastsChloroplasts
Chapter 20
KinetoplastidsKinetoplastids
All species have one or more flagellaAll species have one or more flagella• Can be used for propulsion, sensing, or Can be used for propulsion, sensing, or
food gatheringfood gathering
Many are free-living in soil and waterMany are free-living in soil and water
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KinetoplastidsKinetoplastids
Some species live in a symbiotic Some species live in a symbiotic mutualistic association within another mutualistic association within another organismorganism• Some species digest cellulose in termite Some species digest cellulose in termite
gutsguts• Trypanosomes live within tsetse flies and Trypanosomes live within tsetse flies and
cause African sleeping sickness in fly-cause African sleeping sickness in fly-bitten mammalsbitten mammals
Trypanosomes infect the blood causing Trypanosomes infect the blood causing African sleeping sicknessAfrican sleeping sickness
Chapter 20Trypanosomes in BloodTrypanosomes in Blood
Chapter 20
The StramenophilesThe Stramenophiles
Have fine, hair-like projections on flagellaHave fine, hair-like projections on flagellaMostly single-celled but some Mostly single-celled but some multicellularmulticellular
Some are photosynthetic speciesSome are photosynthetic speciesMajor stramenophile groupsMajor stramenophile groups•Water moldsWater molds• DiatomsDiatoms• Brown algaeBrown algae
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Water MoldsWater Molds
Also known as Also known as oomycetesoomycetesLong filaments aggregated into cottony Long filaments aggregated into cottony tuftstufts
Many are soil and water-based Many are soil and water-based decomposersdecomposers
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Water MoldsWater Molds
Profound economic impacts caused by Profound economic impacts caused by water moldswater molds• Late blightLate blight attacks potato plants (caused attacks potato plants (caused
Irish potato famine in 1845)Irish potato famine in 1845)• One species causes One species causes downy mildewdowny mildew
(nearly destroyed French wine industry (nearly destroyed French wine industry in 1870s)in 1870s)
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A Parasitic Water MoldA Parasitic Water Mold
Downy mildew on grapesDowny mildew on grapesDowny mildew on grapesDowny mildew on grapes
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DiatomsDiatoms
Found in both fresh and salt waterFound in both fresh and salt waterPhotosyntheticPhotosyntheticProduce shells of silica that fit togetherProduce shells of silica that fit togetherDiatomaceous earth is deposits of diatom Diatomaceous earth is deposits of diatom shells (mined and used as an abrasive)shells (mined and used as an abrasive)
Chapter 20
Chapter 20
DiatomsDiatoms
Part of floating Part of floating phytoplanktonphytoplankton community community• Important in absorbing COImportant in absorbing CO22 and and
producing Oproducing O22
• Phytoplankton perform 70% of all Phytoplankton perform 70% of all photosynthesisphotosynthesis
Diatoms are important as food in marine Diatoms are important as food in marine food websfood webs• Herbivorous organisms “graze” on these Herbivorous organisms “graze” on these
“pastures of the sea”“pastures of the sea”
Chapter 20
Brown AlgaeBrown Algae
Form multicellular aggregates (seaweeds)Form multicellular aggregates (seaweeds)Superficially similar but not closely related Superficially similar but not closely related to plantsto plants
Contain brownish-yellow and green Contain brownish-yellow and green (chlorophyll) pigments producing (chlorophyll) pigments producing brown/olive appearancebrown/olive appearance
Chapter 20
Brown AlgaeBrown Algae
Nearly all marineNearly all marine• Found along rocky shores of temperature Found along rocky shores of temperature
oceansoceans• Includes giant kelp Includes giant kelp
– Several species use gas-filled floats to support Several species use gas-filled floats to support bodybody
– Giant kelp forests provide food and shelter for Giant kelp forests provide food and shelter for sea animalssea animals
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Diverse Brown AlgaeDiverse Brown Algae
Fucus Fucus sp.sp.Fucus Fucus sp.sp.
Giant KelpGiant KelpGiant KelpGiant Kelp
Chapter 20
The AlveolatesThe Alveolates
Single-celled protists with small cavities Single-celled protists with small cavities beneath cell surface (alveoli)beneath cell surface (alveoli)
Comprise a distinct lineageComprise a distinct lineageNutritional modes include photosynthetic, Nutritional modes include photosynthetic, parasitic, and predatoryparasitic, and predatory
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The AlveolatesThe Alveolates
Major alveolate groupsMajor alveolate groups• DinoflagellatesDinoflagellates• ApicomplexansApicomplexans• CiliatesCiliates
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DinoflagellatesDinoflagellates
Mostly photosyntheticMostly photosyntheticTwo whip-like flagellaTwo whip-like flagellaMost species live in salt waterMost species live in salt waterSome species bioluminescentSome species bioluminescentCertain specialized dinoflagellates live Certain specialized dinoflagellates live withinwithin coral, clam, and other protistan coral, clam, and other protistan hostshosts
Cell wall resembles armored platesCell wall resembles armored plates
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Dinoflagellates & Red TideDinoflagellates & Red Tide
Red TideRed TideRed TideRed Tide
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DinoflagellatesDinoflagellates
Nutrient-rich water causes population Nutrient-rich water causes population explosion called “red tides”explosion called “red tides”• Substantial fish kills result from oxygen Substantial fish kills result from oxygen
depletion and clogged gillsdepletion and clogged gills• Oysters, mussels, and clams benefit from Oysters, mussels, and clams benefit from
large food supply but may accumulate large food supply but may accumulate nerve poisonnerve poison• Lethal paralytic shellfish poisoning in Lethal paralytic shellfish poisoning in
humans may result from eating these humans may result from eating these shellfishshellfish
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ApicomplexansApicomplexans
Also known as Also known as sporozoanssporozoansAll members are parasiticAll members are parasiticForm infectious spores Form infectious spores Spores transmitted between hosts by food, Spores transmitted between hosts by food, water, or insect biteswater, or insect bites
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ApicomplexansApicomplexans
Complex life cycle (e.g. Complex life cycle (e.g. Plasmodium- Plasmodium- malarial parasite)malarial parasite)• Parasite passed to human by Parasite passed to human by Anopheles Anopheles
mosquitomosquito• PlasmodiumPlasmodium develops in liver, makes spores develops in liver, makes spores
in red blood cells (causing fever upon in red blood cells (causing fever upon release)release)• New mosquitoes acquire parasite while New mosquitoes acquire parasite while
feeding on bloodfeeding on blood• Plasmodium quickly evolves resistance to Plasmodium quickly evolves resistance to
drugsdrugs
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Chapter 20
CiliatesCiliates
Inhabits both fresh and salt waterInhabits both fresh and salt waterHighly complex unicellular organizationHighly complex unicellular organization• Specialized organellesSpecialized organelles• Cilia that propel cells through water at 1 Cilia that propel cells through water at 1
mm/smm/s
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CiliatesCiliates
Examples of ciliate complexityExamples of ciliate complexity• ParameciumParamecium (contractile vacuoles, (contractile vacuoles,
nervous system)nervous system)• DidiniumDidinium (predator of other microbes) (predator of other microbes)
ParameciumParamecium has vacuoles and cilia has vacuoles and cilia
Chapter 20The Complexity of CiliatesThe Complexity of Ciliates
MacronucleusMacronucleusMacronucleusMacronucleusMicronucleusMicronucleusMicronucleusMicronucleus
Food VacuoleFood VacuoleFood VacuoleFood Vacuole
Oral GrooveOral GrooveOral GrooveOral Groove
Contractile VacuoleContractile VacuoleContractile VacuoleContractile Vacuole
CiliaCiliaCiliaCilia
Food VacuoleFood Vacuoleformingforming
Food VacuoleFood Vacuoleformingforming
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The CercozoansThe Cercozoans
CercozoansCercozoans have thin, threadlike have thin, threadlike psuedopods, which extend through psuedopods, which extend through hard shells in some specieshard shells in some species
Cercozoans includeCercozoans include• ForaminiferaForaminifera• RadiolariansRadiolarians
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The CercozoansThe Cercozoans
Foraminiferans produce elaborate Foraminiferans produce elaborate calcium carbonate shells with holescalcium carbonate shells with holes• Deposits of fossilized foraminiferans Deposits of fossilized foraminiferans
form chalkform chalk
Radiolarians have silica shellsRadiolarians have silica shells
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HeliozoansHeliozoans
Chapter 20
Chapter 20
The AmoebozoansThe Amoebozoans
Amoebozoans Amoebozoans move by extending finger-move by extending finger-shaped pseudopods, also used for shaped pseudopods, also used for feedingfeeding
Inhabit aquatic and terrestrial Inhabit aquatic and terrestrial environmentsenvironments
Generally do not have shellsGenerally do not have shellsThe major groups of amoebozoans are The major groups of amoebozoans are • Amoebas Amoebas • Slime moldsSlime molds
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The AmoebozoansThe Amoebozoans
AmoebasAmoebas• Found in freshwater lakes and pondsFound in freshwater lakes and ponds• Predators that stalk and engulf preyPredators that stalk and engulf prey• One species causes amoebic dysenteryOne species causes amoebic dysentery
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The AmoebasThe Amoebas
Chapter 20
The Slime MoldsThe Slime Molds
Distinctly unique lineage among protistsDistinctly unique lineage among protistsPhysical form blurs distinction between Physical form blurs distinction between a colony versus an individual a colony versus an individual
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The Slime MoldsThe Slime Molds
Two-phase life cycleTwo-phase life cycle•Mobile feeding stageMobile feeding stage• Stationary, reproductive stage forming a Stationary, reproductive stage forming a
fruiting bodyfruiting body
Two main typesTwo main types• AcellularAcellular• CellularCellular
Chapter 20
Acellular Slime MoldsAcellular Slime Molds
Also known as Also known as plasmodial slime moldsplasmodial slime moldsComposed of a thinly spread cytoplasm Composed of a thinly spread cytoplasm with multiple diploid nucleiwith multiple diploid nuclei
Plasmodial mass feeds on bacteria and Plasmodial mass feeds on bacteria and organic matter by engulfing themorganic matter by engulfing them
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Acellular Slime MoldsAcellular Slime Molds
Can form bright yellow or orange Can form bright yellow or orange massesmasses
Dry conditions or starvation stimulate Dry conditions or starvation stimulate fruiting body formationfruiting body formation• Haploid spores producedHaploid spores produced• Spores disperse and germinate into a Spores disperse and germinate into a
new plasmodiumnew plasmodium
Chapter 20
The Acellular Slime Mold The Acellular Slime Mold PhysarumPhysarum
(a)(a)(a)(a) (b)(b)(b)(b)
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Cellular Slime MoldsCellular Slime Molds
Live in soil as independent haploid cellsLive in soil as independent haploid cellsPseudopodia surround and engulf food Pseudopodia surround and engulf food (like bacteria)(like bacteria)
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Cellular Slime MoldsCellular Slime Molds
Food scarcity creates a Food scarcity creates a pseudoplasmodiumpseudoplasmodium• Individual cells release chemical signal if Individual cells release chemical signal if
food is scarcefood is scarce• Dense, slug-like aggregation of cells formsDense, slug-like aggregation of cells forms• ““Slug” crawls towards light, forms a Slug” crawls towards light, forms a
fruiting bodyfruiting body• Haploid spores produced are dispersed to Haploid spores produced are dispersed to
form new single-celled individualsform new single-celled individuals
Chapter 20
Single, amoeba-like cells emerge from spores, crawl, and feed.
When food is scarce, cells aggregate into slug-like mass called pseudoplasmodium.
Pseudoplasmodium migrates toward light, forms fruiting bodies; produces spores.
fruiting bodies
spores
nucleus
The Life Cycle of aThe Life Cycle of aCellular Slime MoldCellular Slime Mold
Chapter 20
The Red AlgaeThe Red Algae
Multicellular, photosynthetic seaweedsMulticellular, photosynthetic seaweedsPigments combined with chlorophyll Pigments combined with chlorophyll produce bright red to black produce bright red to black appearancesappearances
Found exclusively in marine Found exclusively in marine environmentsenvironments
Chapter 20
The Red AlgaeThe Red Algae
Very common in deep, clear tropical Very common in deep, clear tropical waterswaters• Red pigments absorb deeply penetrating Red pigments absorb deeply penetrating
blue-green lightblue-green light• Can therefore live deeper than other Can therefore live deeper than other
seaweedsseaweeds
Chapter 20
The Red AlgaeThe Red Algae
Diversity of forms and usesDiversity of forms and uses• Some species deposit calcium carbonateSome species deposit calcium carbonate• Some species harvested for food Some species harvested for food • Energy captured by red algae important in Energy captured by red algae important in
food chainsfood chains• Products extracted from red algae include:Products extracted from red algae include:
Carrageenan (stabilizing agent)Carrageenan (stabilizing agent)Agar (substrate for bacteria in Agar (substrate for bacteria in
petri dishes)petri dishes)
Chapter 20
The Red AlgaeThe Red Algae
Multicellular, photosynthetic seaweeds, Multicellular, photosynthetic seaweeds, ranging in color from bright red to ranging in color from bright red to nearly black nearly black
Live in clear tropical oceansLive in clear tropical oceansSome species deposit calcium Some species deposit calcium carbonate, which contributes to the carbonate, which contributes to the formation of reefs formation of reefs
Chapter 20
Red AlgaeRed Algae
Chapter 20
The Green AlgaeThe Green AlgaeAll species photosynthetic All species photosynthetic Both multicellular and unicellular speciesBoth multicellular and unicellular speciesFound in both freshwater and marine Found in both freshwater and marine environmentsenvironments
Some form long filamentous chains of cells Some form long filamentous chains of cells (e.g. (e.g. SpirogyraSpirogyra))
Chapter 20
Spirogyra: A Green AlgaeSpirogyra: A Green Algae
Chapter 20
The Green AlgaeThe Green Algae
Some form colonies of clustered cells (e.g. Some form colonies of clustered cells (e.g. VolvoxVolvox))
Mostly microscopic forms but Mostly microscopic forms but UlvaUlva (sea (sea lettuce) is a multicellular leaf-sized green lettuce) is a multicellular leaf-sized green algal seaweedalgal seaweed
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Chapter 20
The Green AlgaeThe Green Algae
Green algae are closely related to plantsGreen algae are closely related to plantsThe earliest plants may have been similar to The earliest plants may have been similar to today’s multicellular green algaetoday’s multicellular green algae
Chapter 20
Protists and LifeProtists and Life
Marine phytoplankton: 70% of all photosynthesisMarine phytoplankton: 70% of all photosynthesis
Diatoms - abrasive products and oil reservesDiatoms - abrasive products and oil reserves
Sarcodines and limestone depositsSarcodines and limestone deposits
Protists and diseaseProtists and disease• Water molds - downy mildew, late blight of potatoWater molds - downy mildew, late blight of potato• Dinoflagellates and "red tide," shellfish poisoningDinoflagellates and "red tide," shellfish poisoning• Zooflagellates - African sleeping sickness, GiardiaZooflagellates - African sleeping sickness, Giardia• Sarcodines - amoebic dysenterySarcodines - amoebic dysentery
Sporozoans - Sporozoans - PlasmodiumPlasmodium and malaria and malaria
Chapter 20
Giardia: the Curse of CampersGiardia: the Curse of Campers
Chapter 20Chapter 20
The Diversity of ProtistsThe Diversity of Protists