- Protists are a diverse group of eukaryotic organisms, most of which are microscopic. They are classified into three main groups: animal-like protists which are heterotrophic and motile, plant-like protists which are photosynthetic, and fungi-like protists which are decomposers. - Protists exhibit characteristics of both unicellular and multicellular organisms. They can reproduce both sexually through meiosis and gamete formation, and asexually through binary fission. Many important human diseases are caused by parasitic protists, such as malaria caused by Plasmodium and African sleeping sickness caused by Trypanosoma.

1. Kingdom ProtistaKingdom Protista

2. KEY CONCEPTSKEY CONCEPTS
• Protists are a diverse group ofProtists are a diverse group of
eukaryotic organisms, most of which areeukaryotic organisms, most of which are
microscopicmicroscopic

3. ProtistaProtista
• Not a really valid “Kingdom”Not a really valid “Kingdom”
•
Few real evolutionary relationshipsFew real evolutionary relationships
• ContainsContains
•
AlgaeAlgae: “plant-like” protists: “plant-like” protists
•
ProtozoaProtozoa: “animal-like” protists: “animal-like” protists
•
Slime & Water moldsSlime & Water molds: fungal-like: fungal-like
protistsprotists

5. What Are Protists?What Are Protists?
• ““Dumping ground”Dumping ground”
kingdomkingdom
• EukaryoticEukaryotic
• HeterotrophicHeterotrophic and/orand/or
autotrophicautotrophic
• SingleSingle oror
multicellularmulticellular
• Ancestors toAncestors to
animals, plants,animals, plants,
fungifungi

6. Animal-like ProtistsAnimal-like Protists
• Called Protozoans
• Unicellular
• Require water (live in
water or moist soil)
• Most heterotrophic
• Some photosynthetic
• Most are free-living
• Some parasitic

7. All Life Functions in Just One CellAll Life Functions in Just One Cell
• Have food and wasteHave food and waste
VACUOLESVACUOLES for storingfor storing
and digesting food &and digesting food &
wasteswastes
• Many are capable ofMany are capable of
MOVEMENTMOVEMENT
• RESPONDRESPOND toto
environment – someenvironment – some
have light sensitivehave light sensitive
eyespoteyespot
Amoeba
Paramecium

8. All Life Functions in Just One CellAll Life Functions in Just One Cell
• MaintainMaintain
HOMEOSTASISHOMEOSTASIS
• Contractile VacuolesContractile Vacuoles
pump out excesspump out excess
waterwater
• FormForm Protective CystsProtective Cysts
when food or water iswhen food or water is
scarce (dormant stagescarce (dormant stage
with hard covering)with hard covering) Contractile VacuoleContractile Vacuole
PumpingPumping

9. Plant-like ProtistsPlant-like Protists
Red Algae
Golden Algae
• Photosynthetic
• No true roots, stems,
leaves

10. Plant-like ProtistsPlant-like Protists
Green Algae
Red AlgaeBrown Algae
Golden Algae
• Photosynthetic
• No true roots, stems, leaves

11. Fungi-like ProtistsFungi-like Protists
• Heterotrophic
• Decomposers
• No cell walls
Slime Molds
Water Molds

12. ReproductionReproduction
• ReproductionReproduction
•
Asexual:Asexual: fissionfission
•
Sexual: produceSexual: produce gametesgametes (specialized sex(specialized sex
cells)cells)
• Advantage: new combinations of genesAdvantage: new combinations of genes fromfrom
both parents (Red Queen Hypothesis)both parents (Red Queen Hypothesis)

13. ReproductionReproduction
• All reproduceAll reproduce
ASEXUALLYASEXUALLY
• Binary FissionBinary Fission --
divides into 2divides into 2
identicalidentical
individualsindividuals
(clones)(clones)
• RapidRapid
reproductive ratereproductive rate

14. Some Reproduce SEXUALLYSome Reproduce SEXUALLY
ConjugationConjugation -- Opposite mating strains pairOpposite mating strains pair
and exchange genetic material (DNA)and exchange genetic material (DNA)

15. ProtistProtist
CharacteristicsCharacteristics

16. General CharacteristicsGeneral Characteristics
• EukaryoticEukaryotic
• UnicellularUnicellular
• Some may live in coloniesSome may live in colonies
• May be Autotrophic orMay be Autotrophic or
Heterotrophic or BothHeterotrophic or Both
• Some are motileSome are motile
• Appeared about 1.5 BYAAppeared about 1.5 BYA

17. Classified into Three Main GroupsClassified into Three Main Groups
• Animal-likeAnimal-like… heterotrophs… heterotrophs
capable of locomotioncapable of locomotion
• Plant-likePlant-like… photosynthetic… photosynthetic
autotrophsautotrophs
• Fungus-likeFungus-like… decomposers that… decomposers that
reproduce by sporesreproduce by spores
• Some protistsSome protists may exhibit bothmay exhibit both
animal-like & plant-likeanimal-like & plant-like
characteristicscharacteristics

18. Sizes of ProtistsSizes of Protists
• UnicellularUnicellular organismsorganisms
•
microscopicmicroscopic
• ColoniesColonies
•
loosely connected groups of cellsloosely connected groups of cells
• CoenocytesCoenocytes
•
multinucleate masses of cytoplasmmultinucleate masses of cytoplasm
• MulticellularMulticellular organismsorganisms
•
composed of many cellscomposed of many cells
•
can get very large – some brown algae (thecan get very large – some brown algae (the
giant kelps) can be 100 feet in lengthgiant kelps) can be 100 feet in length

19. LocomotionLocomotion
• Protozoa used to be classified accordingProtozoa used to be classified according
to how they move.to how they move.
•
Ciliates use fine “hairs” calledCiliates use fine “hairs” called ciliacilia
•
Flagellates use longer, whip-like hairs calledFlagellates use longer, whip-like hairs called
flagellaflagella
•
Amoebas and their relatives useAmoebas and their relatives use pseudopodiapseudopodia
• Pseudopodia are also used to capture foodPseudopodia are also used to capture food
•
Sporozoans (apicomplexans) don’t have anySporozoans (apicomplexans) don’t have any
ability to move (ability to move (non-motilenon-motile))

20. ImportanceImportance
• Importance of ProtistsImportance of Protists
•
HeterotrophicHeterotrophic protists =protists = protozoaprotozoa
• Consume bacteriaConsume bacteria and other protistsand other protists
•
Components of aquatic and soilComponents of aquatic and soil food websfood webs
•
help withhelp with recycling nutrientsrecycling nutrients
• Some causeSome cause diseasedisease
•
MalariaMalaria
•
DysenteryDysentery
•
Sleeping sicknessSleeping sickness
•
othersothers

21. InteractionsInteractions
• Protists are free-living orProtists are free-living or symbioticsymbiotic
• Symbiotic relationships range fromSymbiotic relationships range from
mutualismmutualism toto parasitismparasitism

22. Classification of Selected MedicallyClassification of Selected Medically
Important ProtozoaImportant Protozoa
•
Four groupsFour groups
• Mastigophora - flagellatesMastigophora - flagellates
• Sarcodina - amoebaeSarcodina - amoebae
• Ciliophora - ciliatesCiliophora - ciliates
• Apicomplexa – aka SporozoansApicomplexa – aka Sporozoans
•
Based on:Based on:
• Method of motilityMethod of motility
• Mode of reproductionMode of reproduction
• Stages in the lifecycleStages in the lifecycle

23. Animal-likeAnimal-like
ProtistsProtists
classified byclassified by
method ofmethod of
movementmovement

24. Phylum RhizopodaPhylum Rhizopoda
(formerly Sarcodina) : ex.(formerly Sarcodina) : ex. AmoebaAmoeba

25. TheThe AmoebaAmoeba usesuses
pseudopodiapseudopodia for locomotion.for locomotion.

26. TheThe AmoebaAmoeba in 3D – noticein 3D – notice
the pseudopodsthe pseudopods

28. AmoebaAmoeba surround and engulf theirsurround and engulf their
food… the process is calledfood… the process is called
phagocytosisphagocytosis..

29. AnAn AmoebaAmoeba eating aeating a
ParameciumParamecium..

30. CiliophoraCiliophora
• all use cilia for movementall use cilia for movement
• have many specialized structures,have many specialized structures,
including mouths, anal pores,including mouths, anal pores,
contractile vacuoles, and two nucleicontractile vacuoles, and two nuclei
(a large macronucleus and small(a large macronucleus and small
micronuclei)micronuclei)
• Ex. –Ex. – ParameciumParamecium andand StentorStentor

31. Phylum Ciliophora: ex.Phylum Ciliophora: ex. ParameciumParamecium

32. 3D view – taken by a3D view – taken by a
scanningscanning
electron microscopeelectron microscope

33. A closer look at the Cilia….A closer look at the Cilia….
its means of locomotionits means of locomotion

36. another Ciliate:another Ciliate: StentorStentor

37. PhylumPhylum
ZoomastigophoraZoomastigophora
• have flagellahave flagella
• some species ofsome species of
zooflagellateszooflagellates
have mutualistichave mutualistic
relationshipsrelationships
• ex.-ex.- TrichonymphaTrichonympha
digests cellulosedigests cellulose
in the guts ofin the guts of
termitestermites

38. Others are parasites, likeOthers are parasites, like
TrypanosomaTrypanosoma, which causes, which causes
African Sleeping Sickness (coma).African Sleeping Sickness (coma).

39. TrypanosomaTrypanosoma

40. TrypanosomaTrypanosoma
Tsetse Fly: carries Trypanosoma to
humans; in other words, it’s a Vector
White Blood Cell
Red Blood Cells
Trypanosoma

42. Phylum SporozoaPhylum Sporozoa
• are parasitesare parasites
• have no means of locomotionhave no means of locomotion
• form spores that are dispersedform spores that are dispersed
by one or more hostsby one or more hosts
• ex.ex. PlasmodiumPlasmodium, which causes, which causes
malariamalaria

43. Portions of the Life Cycle ofPortions of the Life Cycle of
Plasmodium vivaxPlasmodium vivax
It’s
Vector:
Anopheles
Mosquito
Plasmodium vivax
Red Blood Cells

45. Pathogenic Flagellates:Pathogenic Flagellates:
TrypanosomesTrypanosomes
• Giardia lambliaGiardia lamblia
• Trichomonas vaginalisTrichomonas vaginalis
• GenusGenus TrypanosomaTrypanosoma
•
T. bruceiT. brucei causes sleeping sicknesscauses sleeping sickness
•
T. cruziT. cruzi causes Chagas diseasecauses Chagas disease

46. GiardiaGiardia

47. GiardiasisGiardiasis
• Fecal-oral route of infectionFecal-oral route of infection
•
recreational water, water, fomites, contaminatedrecreational water, water, fomites, contaminated
uncooked fooduncooked food
• Symptoms normally begin 1 to 2 weeks (average 7Symptoms normally begin 1 to 2 weeks (average 7
days) after becoming infected.days) after becoming infected.
• SymptomsSymptoms
•
DiarrheaDiarrhea
•
Gas or flatulenceGas or flatulence
•
Greasy stools that tend to floatGreasy stools that tend to float
•
Stomach or abdominal crampsStomach or abdominal cramps
•
Upset stomach or nauseaUpset stomach or nausea
• May lead to weight loss and dehydrationMay lead to weight loss and dehydration
• Symptoms of giardiasis may last 2 to 6 weeks.Symptoms of giardiasis may last 2 to 6 weeks.

48. Trichomonas vaginalisTrichomonas vaginalis
A flagellate - causesA flagellate - causes
Trichomoniasis, a sexuallyTrichomoniasis, a sexually
transmitted diseasetransmitted disease

49. TrichomoniasisTrichomoniasis
• STDSTD
• Clinical Features:Clinical Features:
•
Trichomonas vaginalisTrichomonas vaginalis infection in women isinfection in women is
frequently symptomatic. frequently symptomatic.
•
Vaginitis with a purulent discharge is theVaginitis with a purulent discharge is the
prominent symptom, and can be accompanied byprominent symptom, and can be accompanied by
vulvar and cervical lesions, abdominal pain, dysuriavulvar and cervical lesions, abdominal pain, dysuria
and dyspareunia. and dyspareunia.
•
The incubation period is 5 to 28 days. The incubation period is 5 to 28 days.
•
In men, the infection is frequently asymptomatic;In men, the infection is frequently asymptomatic;
occasionally, urethritis, epididymitis, andoccasionally, urethritis, epididymitis, and
prostatitis can occur.prostatitis can occur.

51. Tsetse fly
TrypanosomesTrypanosomes
(flagellates) in blood(flagellates) in blood
smearsmear
Kissing bugKissing bug
Tsetse FlyTsetse Fly

52. 25 µm
Flagellum
Red blood
cells
Trypanosome
with undulating
membrane

53. Figure 5.27
T. cruzi causes
Chagas disease

54. East Africa West Africa
African Sleeping Sickness

55. African Sleeping SicknessAfrican Sleeping Sickness
• Bite reactionBite reaction
• ParasitemiaParasitemia
•
attacks of fever which starts 2-3 weeksattacks of fever which starts 2-3 weeks
after the biteafter the bite
• CNS StageCNS Stage
•
changes in character and personalitychanges in character and personality
• Terminal stage is marked by wasting andTerminal stage is marked by wasting and
emaciationemaciation
• Death results from coma, intercurrentDeath results from coma, intercurrent
infection or cardiac failureinfection or cardiac failure

57. SarcodinaSarcodina (Amoebas)(Amoebas)
• PseudopodsPseudopods
• Some have flagellated reproductive statesSome have flagellated reproductive states
• Asexual reproduction by fissionAsexual reproduction by fission
• Two groups have an external shellTwo groups have an external shell
• Mostly uninucleateMostly uninucleate
• Usually encystUsually encyst
• Most free-livingMost free-living
• ExamplesExamples
•
EntamoebaEntamoeba
•
ForaminiferaForaminifera
•
RadiolariansRadiolarians

58. Figure 5.24

59. Infective Amoebas:Infective Amoebas: EntamoebaEntamoeba
• Amoebiasis caused byAmoebiasis caused by EntamoebaEntamoeba
histolyticahistolytica
• Fourth most common protozoanFourth most common protozoan
infection in the worldinfection in the world
• AkaAka amoebic dysenteryamoebic dysentery

60. Figure 5.28
Entamoeba histolytica

61. Entameoba histolytica
Causes amoebic
dysentery (diarrhea)
and can enter the liver,
lungs, and brain

62. Naegleria fowleri

63. Foraminifera

65. Cyanophora paradoxaCyanophora paradoxa - has no- has no
chloroplasts; contains anchloroplasts; contains an
endosymbiotic cyanobacterium.endosymbiotic cyanobacterium.
PelomyxaPelomyxa has nohas no
mitochondria; thismitochondria; this
amoeba depends onamoeba depends on
aerobic bacterialaerobic bacterial
symbionts to carry outsymbionts to carry out
respirationrespiration
More support for the theory:More support for the theory:
Living organisms that containLiving organisms that contain
endosymbiotic bacteria that carryendosymbiotic bacteria that carry
out vital functions in the cell.out vital functions in the cell.

66. AmoebaeAmoebae

67. CiliophoraCiliophora (Ciliated)(Ciliated)
• Trophozoites mobile by ciliaTrophozoites mobile by cilia
• Some have cilia in tufts for feeding andSome have cilia in tufts for feeding and
attachmentattachment
• Most develop cystsMost develop cysts
• Both macronuclei and micronucleiBoth macronuclei and micronuclei
• Division by transverse fissionDivision by transverse fission
• Most have definite mouth and feedingMost have definite mouth and feeding
organelleorganelle
• Show relatively advanced behaviorShow relatively advanced behavior
• Majority are free-living and harmlessMajority are free-living and harmless

68. CiliatesCiliates

71. Balantidium coliBalantidium coli
• Only known ciliate that is pathogenic inOnly known ciliate that is pathogenic in
humanshumans
• Affects humans, other primates, and pigsAffects humans, other primates, and pigs
which are the reservoirwhich are the reservoir
• Lives in the large intestine and causesLives in the large intestine and causes
diarrheadiarrhea
• Trophozoites can also be detected in tissue.Trophozoites can also be detected in tissue.
• Collect a tissue specimen from the largeCollect a tissue specimen from the large
intestine, by sigmoidoscopyintestine, by sigmoidoscopy

72. TrophozoitesTrophozoites
CystCyst

73. • Most cases are asymptomatic. Most cases are asymptomatic.
•
Clinical manifestations, whenClinical manifestations, when
present, include persistentpresent, include persistent
diarrhea, occasionally dysentery,diarrhea, occasionally dysentery,
abdominal pain, and weight loss. abdominal pain, and weight loss.
•
Symptoms can be severe inSymptoms can be severe in
debilitated persons.debilitated persons.
• Diagnosis is based on detectionDiagnosis is based on detection
of trophozoites in stoolof trophozoites in stool
specimens or in tissue collectedspecimens or in tissue collected
during endoscopy. during endoscopy.
• Repeated stool samplesRepeated stool samples
• TreatmentTreatment
•
Tetracycline with metronidazoleTetracycline with metronidazole
and iodoquinol as alternativesand iodoquinol as alternatives

75. ApicomplexaApicomplexa (Sporozoa)(Sporozoa)
• Most not motile except male gametesMost not motile except male gametes
• Complex life cyclesComplex life cycles
• ProduceProduce sporozoitessporozoites following sexualfollowing sexual
reproductionreproduction
• Important in transmission of infectionsImportant in transmission of infections
• Most form oocystsMost form oocysts
• Entire group is parasiticEntire group is parasitic
• ExamplesExamples
•
PlasmodiumPlasmodium sppspp..
•
Toxoplasma gondiiToxoplasma gondii
•
Cryptosporidium parvumCryptosporidium parvum

77. Mosquito - transmits theMosquito - transmits the
malaria parasitemalaria parasite PlasmodiumPlasmodium
vivaxvivax (a sporozoan)(a sporozoan)
Malaria parasite inMalaria parasite in
red blood cellsred blood cells
Parasites breakingParasites breaking
out of red bloodout of red blood
cellscells

78. Malaria

79. ToxoplasmosisToxoplasmosis

80. ToxoplasmosisToxoplasmosis
• Parasite causes eye and brain damage in aParasite causes eye and brain damage in a
baby, if untreated.baby, if untreated.
• Acute infection in older children and adultsAcute infection in older children and adults
may be without symptoms, cause flu likemay be without symptoms, cause flu like
illness or enlarged lymph glands.illness or enlarged lymph glands.
• Latent parasite occurs very commonly inLatent parasite occurs very commonly in
people infecting approximately a third to apeople infecting approximately a third to a
half of all humans.half of all humans.
•
Can cause active disease if a person becomesCan cause active disease if a person becomes
immune compromisedimmune compromised

81. Protozoan Identification andProtozoan Identification and
CultivationCultivation
• Shape and size of cellShape and size of cell
• Type, number, and distribution ofType, number, and distribution of
locomotor structureslocomotor structures
• Presence of special organelles or cystsPresence of special organelles or cysts
• Number of nucleiNumber of nuclei
• Can be cultivated on artificial media orCan be cultivated on artificial media or
in laboratory animalsin laboratory animals

82. Toxoplasma gondiiToxoplasma gondii
• Clinical FeaturesClinical Features::
•
Generally an asymptomatic or mild self-limitingGenerally an asymptomatic or mild self-limiting
infection. infection.
•
Immunodeficient patientsImmunodeficient patients
• brain lesionsbrain lesions
• pneumonitispneumonitis
•
Pregnant women/infantPregnant women/infant
• miscarriage; still birthsmiscarriage; still births
• cerebral palsey; seisurescerebral palsey; seisures
• mental retardationmental retardation
• eye infections; impairedeye infections; impaired
visionvision
• enlarged liver and spleenenlarged liver and spleen

83. CryptosporidiumCryptosporidium can be a problem incan be a problem in
municipal water supplies.municipal water supplies.
CryptosporidiumCryptosporidium affectsaffects
humans, dogs, and cattlehumans, dogs, and cattle

84. Cryptosporidium
Intracellular parasite
Causes diarrhea
Affects humans, cattle,
sheep, dogs
No effective drug
treatment for
cryptosporidiosis
Antibiotics are
contraindicated;
supportive care only

87. Important Protozoan PathogensImportant Protozoan Pathogens

88. Phylum ForaminiferaPhylum Foraminifera
• have a protective shell or TEST, usuallyhave a protective shell or TEST, usually
made of calcium carbonatemade of calcium carbonate
• layers of tests can deposit on the oceanlayers of tests can deposit on the ocean
floorfloor
•
these can form limestone and chalk, likethese can form limestone and chalk, like
the White Cliffs of Doverthe White Cliffs of Dover
•
Some species of forams are good indicatorsSome species of forams are good indicators
of oil deposits belowof oil deposits below

89. Cliffs ofCliffs of
DoverDover

90. Plant-like ProtistsPlant-like Protists
are classified byare classified by
CCOOLLOORR

91. Plant Like ProtistaPlant Like Protista
• Importance of ProtistsImportance of Protists
•
AutotrophicAutotrophic protists =protists = algaealgae
• Photosynthetic algae are the most importantPhotosynthetic algae are the most important
primary producersprimary producers of the world’s freshwaterof the world’s freshwater
and marine ecosystemsand marine ecosystems
•
Many are microscopicMany are microscopic
•
Some are huge: kelpSome are huge: kelp
• Few cause diseaseFew cause disease
•
Toxic blooms of dinoflagellates causeToxic blooms of dinoflagellates cause
• Red tidesRed tides
• shellfish poisoningshellfish poisoning

92. Diatoms
Giant Kelp

93. Photosynthetic ProducersPhotosynthetic Producers
6 CO2 + 6H2O 6 C6H12O6
Photosynthesis
Respiration
Energy
Energy

94. Lake Trophic LevelsLake Trophic Levels
ZooplanktonZooplankton
11oo
consumersconsumers
BluegillBluegill
22oo
consumersconsumers
Algae - producersAlgae - producers
BassBass
33oo
consumersconsumers
OspreyOsprey
HumansHumans
44oo
consumersconsumers

95. Phylum ChlorophytaPhylum Chlorophyta
• have both chlorophyllhave both chlorophyll aa andand bb (so they(so they
are green)are green)
• have cellulose cell wallshave cellulose cell walls
• store carbohydrates as starchstore carbohydrates as starch
• have many types of sexual reproductionhave many types of sexual reproduction
• exhibit many types of organizationexhibit many types of organization
--Are thought to be the ancestors of--Are thought to be the ancestors of
plants--plants--

96. Variations in SexualVariations in Sexual
ReproductionReproduction
• IsogamousIsogamous= both sperm and egg= both sperm and egg
are motile and equal in sizeare motile and equal in size
• AnisogamousAnisogamous= both sperm and= both sperm and
egg are motile and differ in sizeegg are motile and differ in size
• OogamousOogamous= large, nonmotile egg= large, nonmotile egg
and small, motile spermand small, motile sperm

97. Variations in SexualVariations in Sexual
ReproductionReproduction

98. Phylum ChlorophytaPhylum Chlorophyta
organizationorganization
1. Unicellular1. Unicellular
2. Filamentous2. Filamentous
3. Colonial3. Colonial
4. Bi-layer4. Bi-layer

99. Unicellular Green AlgaeUnicellular Green Algae
ChlamydomonasChlamydomonas

100. ChlamydomonasChlamydomonas

101. Filamentous Green AlgaeFilamentous Green Algae
SpirogyraSpirogyra
has spiral-shaped chloroplastshas spiral-shaped chloroplasts

102. another filamentous Green Algaeanother filamentous Green Algae
ZygnemaZygnema
2 Star-shaped chloroplasts per2 Star-shaped chloroplasts per
cellscells

103. a colonial Green Algae …a colonial Green Algae … VolvoxVolvox
Mother colony with DaughterMother colony with Daughter
coloniescolonies
Mother Colony
Daughter Colony

104. a bi-layered Greena bi-layered Green
AlgaeAlgae
UlvaUlva (sea lettuce)(sea lettuce)

106. Harvesting UlvaHarvesting Ulva

107. PhylumPhylum
PhaeophytaPhaeophyta
• brown algaebrown algae
• multicellularmulticellular
• flagellated spermflagellated sperm
cellscells
• Ex.:Ex.: FucusFucus & Kelp& Kelp

108. Phylum Pheaophyta:Phylum Pheaophyta:
Brown Algae… Laminaria… KelpBrown Algae… Laminaria… Kelp
Air Bladders:
Used to take blades
to the surface for
photosynthesis

109. Phylum Rhodophyta:Phylum Rhodophyta:
Red AlgaeRed Algae
• are
multicellular
• contain red
accessory
pigments called
phycobilins
• gametes do not
have flagella

110. • formerly known as Pyrrophyta or fireformerly known as Pyrrophyta or fire
algaealgae
• have two flagellahave two flagella
• some are bioluminescent, producingsome are bioluminescent, producing
lightlight
• others produce nerve toxinsothers produce nerve toxins
•
dinoflagellates are collected anddinoflagellates are collected and
concentrated in filter-feedingconcentrated in filter-feeding
Phylum DinoflagellataPhylum Dinoflagellata

111. Phylum DinoflagellataPhylum Dinoflagellata
ex.ex. PeridiniumPeridinium

112. Red Tide-Red Tide-
results from a bloomresults from a bloom
ofof PeridiniumPeridinium

113. Phylum Bacillariophyta:Phylum Bacillariophyta:
Diatoms… have tests (shells) thatDiatoms… have tests (shells) that
contain silica (SiOcontain silica (SiO22), or glass), or glass

114. Diatom StrewDiatom Strew

115. Diatoms - a SEMDiatoms - a SEM
picturepicture

116. Phylum EuglenophytaPhylum Euglenophyta
• have one to three flagella at theirhave one to three flagella at their
leading (apical) endleading (apical) end
• have thin protein strips calledhave thin protein strips called
pellicles wrapped over theirpellicles wrapped over their
membranesmembranes
• have an eyespot that permits themhave an eyespot that permits them
to swim toward lightto swim toward light
• can become heterotrophic whencan become heterotrophic when
there is no lightthere is no light

117. EuglenaEuglena (arrow indicates anterior(arrow indicates anterior
end)end)

118. The Euglena uses a flagella asThe Euglena uses a flagella as
aa
means of locomotion.means of locomotion.

119. PhylumPhylum
ChrysophytaChrysophyta
• Are golden yellowAre golden yellow
• Have one or two apicalHave one or two apical
flagellaflagella

120. MOREMORE
Examples of AutotrophicExamples of Autotrophic
Protists (Algae)Protists (Algae)

121. Giant Kelp Forest

122. Desmids – a type ofDesmids – a type of
green algaegreen algae

123. Green and goldenGreen and golden
algaealgae
SummerSummer

124. TabellariaTabellaria - a diatom Note the sheets- a diatom Note the sheets
of rectangular cellsof rectangular cells

125. AsterionellaAsterionella - a diatom- a diatom

126. DinobryonDinobryon
A chrysophyte algae – Early SpringA chrysophyte algae – Early Spring

127. Gonyaulax (another
flagellate) and view of
red tide

128. Fungal LikeFungal Like
ProtistsProtists

129. HabitatsHabitats
• Most protists live inMost protists live in
•
oceanocean
•
freshwater pondsfreshwater ponds
•
lakeslakes
•
StreamsStreams
•
SoilSoil
• Parasitic protists live in body fluids ofParasitic protists live in body fluids of
hostshosts

130. Phylum Acrasiomycota:Phylum Acrasiomycota:
Cellular Slime MoldsCellular Slime Molds
• have both fungus and protist characteristicshave both fungus and protist characteristics
• spores germinate into amoebas that feed onspores germinate into amoebas that feed on
bacteriabacteria
• When food is depleted,When food is depleted, cyclic AMPcyclic AMP is released,is released,
causing amoebas to aggregate into one unitcausing amoebas to aggregate into one unit
• the crowd of amoebas form a slug that migratesthe crowd of amoebas form a slug that migrates
• cells from the slug form a stalk with a capsule,cells from the slug form a stalk with a capsule,
which makes sporeswhich makes spores
• spores are released, and the cycle repeatsspores are released, and the cycle repeats

131. Acrasiomycota Life CycleAcrasiomycota Life Cycle

132. Phylum AcrasiomycotaPhylum Acrasiomycota
aggregatingaggregating
amoebasamoebas
colony &
fruiting body

133. Phylum Myxomycota: PlasmodialPhylum Myxomycota: Plasmodial
Slime MoldsSlime Molds
• grow as a single, spreading mass or plasmodiumgrow as a single, spreading mass or plasmodium
• feed on decaying vegetationfeed on decaying vegetation
• when the environment becomes unfavorable (nowhen the environment becomes unfavorable (no
food or water), they form stalks and spore-food or water), they form stalks and spore-
producing capsulesproducing capsules
• haploid spores germinate into amoeboid orhaploid spores germinate into amoeboid or
flagellated cellsflagellated cells
• these cells fuse to form a new diploid plasmodiumthese cells fuse to form a new diploid plasmodium

134. Myxomycota Life CycleMyxomycota Life Cycle

135. MyxomycotaMyxomycota

136. Phylum OomycotaPhylum Oomycota
• are parasitic and saprophyticare parasitic and saprophytic
• form filaments, orform filaments, or hyphahyphae (like fungi)e (like fungi)
• secrete enzymes into surroundings &secrete enzymes into surroundings &
absorb nutrients (like fungi)absorb nutrients (like fungi)
• filaments lackfilaments lack septasepta oror cross wallscross walls
resulting in many nuclei in a cell, they areresulting in many nuclei in a cell, they are
coenocyticcoenocytic
• have cell walls made of cellulose, nothave cell walls made of cellulose, not
chitinchitin

137. Examples:Examples:
• water moldswater molds
• downy mildewsdowny mildews
• white rustswhite rusts
OomycotaOomycota
Life CycleLife Cycle

138. Leptomitus
Powdery Mildew

139. Phylum OomycotaPhylum Oomycota
• potatoes are native to North Americapotatoes are native to North America
• they were introduced to Europe andthey were introduced to Europe and
became a staple of the dietbecame a staple of the diet
• during the summer of 1846 most ofduring the summer of 1846 most of
the potato crop was destroyed bythe potato crop was destroyed by
PhytophthoraPhytophthora (an oomycota)(an oomycota)
• nearly 1,000,000 Irish people died, andnearly 1,000,000 Irish people died, and
1,500,000 emigrated to other1,500,000 emigrated to other
countries, like the U.S.countries, like the U.S.

141. Pfiesteria piscicida.Ulcers on fish caused by
Pfiesteria
Note the long flagella

142. Evolutionary ConsiderationsEvolutionary Considerations
• One group of flagellates, theOne group of flagellates, the
choanoflagellates, is thought tochoanoflagellates, is thought to
have given rise to the simplesthave given rise to the simplest
animals, the sponges.animals, the sponges.