“KINGDOM” PROTISTA
Professor Andrea Garrison
Biology 3A
Illustrations ©2014 Cengage Learning unless
otherwise noted
Protista
• Domain Eukarya
• Very diverse
• Unnatural grouping
(polyphyletic)
• Everything that isn’t
animal, plant or fungi
Protista
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Protista
• Described by Leeuwenhoek in 1760s
• Typically unicellular
– Complex cell structure
– Some multicellular
– Some colonial
• Autotrophic, heterotrophic or both
– P/S forms often called algae
• Varied lifestyles: all require moisture
– Seawater, freshwater, soil, decaying organisms, parasitic
– Microscopic protists in lakes/oceans make up phytoplankton
• Food source for zooplankton and rest of food chain
• Some pathogenic
– Amoebic dysentery, sleeping sickness, malaria
Protista
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Protista
• Reproduction asexual or sexual or both
– Asexual
• Binary fission
• Budding
• Colonies
– May show division of labor
– Sexual
• Meiosis, resulting gametes fuse
– Both
• Elaborate life cycles specific to that group
Protista
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Protista
• Cell structure
– Cell wall, shell of mineral or organic matter, or
pellicle
– Most have mitochondria
• Some with very reduced mitochondria
– P/S protists have plastids
• Chloroplasts
– Chl a, and chl b or chl c
– Accessory pigments
• Other plastids contain pigments or store P/S products
Protista
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Protistan Plastid Evolutionary Scenario
Protista
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Protistan Plastid Evolutionary Scenario
Protista
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Protista
• Many freshwater spp
have contractile
vacuole
– Maintain osmotic
balance
– Absent in marine,
parasitic forms,
isosmotic w/
environment
• Many have food
vacuoles
– Intracellular digestion,
wastes expelled
Protista
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Protista
• Metabolism usually
aerobic
• Excretion and
respiration via
diffusion across cell
membrane
Protista
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Protista
• Locomotion
– Motile during at least
part of life cycle
• Flagella
• Cilia
• Pseudopods
– Temporary cytoplasmic
extensions of cell
membrane
– Locomotion
» Amoeboid
movement
– Feeding
Protista
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Protistan Classification
SAR
Protista
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Protistan Classification
• State of flux, not well understood (differs from
text)
• Based on DNA data, structure
• 4 “supergroups” which also include the rest of
Eukarya
– Excavata
– SAR
– Archaeplastida
– Unikonta
Protista
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EXCAVATA
SAR
BIKONTA
Opisthokonta
Amoebozoa
Archaeplastida
Rhizaria
Stramenopila
Alveolata
Euglenozoa
Metamonada
Protistan Classification
ARCHAEPLASTIDA
UNIKONTA
p. 592
Protistan Classification
• 4 supergroups may eventually become
kingdoms or suprakingdoms
• We will look at examples of each group
Protista
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Excavata
• Parasitic, free-living species may be autotrophs
or heterotrophs
• Feeding “groove” (excavate; ex=from,
cavatum=cavity) in many, with flagellum in
groove
• Reduced mitochondria in many
– Mitochondrial genes incorporated into nuclei
• Locomotion via unique flagella
– Crystalline or spiral rod inside
Protista
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Excavata
• 3 clades
– Euglenozoa
– Diplomonada
– Parabasala
Protista
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Excavata
• Clade Euglenozoa
– Highly motile
– Most P/S
– Some heterotrophic, or can be mixotrophic (both
autotrophic and heterotrophic)
Protista
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Excavata
• Subclade Euglenida
– Free-living, most freshwater
– 2 flagella
• 1 anterior flagellum
– Can pull or push
• 1 very reduced
– Most P/S
• Can also absorb nutrients across
cell membrane
– Contractile vacuole
– Spiral-grooved pellicle replaces
cell wall
• Protein strips under cell
membrane
– Photosensitive eyespot
• Stay positioned in optimum light
levels
Protista
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Excavata
• Subclade Kinetoplastida
– Parasites
– Kinetoplast inside
mitochondrion
• Large DNA-protein deposit
– 2 flagella
• 1 may be attached to cell
membrane forming
undulating membrane
– Ex: trypanosomes
• African sleeping sickness,
Chagas disease,
leishmaniasis
Protista
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Excavata
• Clade Diplomonada
– Many parasitic
(intestinal)
– Anaerobic
– 2 nuclei
– Multiple flagella
– Ex: Giardia sp.
Giardia sp.
• Giardiasis
http://www.cdc.gov/parasites/giardia/images/
giardia-banner.jpg
Protista; photo From Brooke, MM, Melvin, DM: Morphology of Diagnostic Stages of Intestinal Parasites of Man. Public Health
Service Publication No. 1966, 1969, http://www.ncbi.nlm.nih.gov/books/NBK7889/figure/A4205/?report=objectonly
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Excavata
• Clade Diplomonada
– Many parasitic
(intestinal)
– Anaerobic
– 2 nuclei
– Multiple flagella
– Ex: Giardia sp.
• Giardiasis
Protista; http://www.cdc.gov/parasites/giardia/pathogen.html
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Excavata
• Clade Parabasala
– Many parasitic
– Anaerobic
– Undulating membrane
attached to flagellum
– Trichomonas vaginalis
• Trichomoniasis
Trichomonas vaginalis
Protista; http://www.cdc.gov/std/trichomonas/stdfact-trichomoniasis.htm
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SAR
• Very diverse group, phylogeny controversial
• 3 clades
– Stramenopila
– Alveolata
– Rhizaria
Protista
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SAR
• Clade Stramenopila
• P/S
• “Hairy” flagellum, usually a shorter smooth
flagellum as well
• 3 subclades
– Bacillariophyta
– Chrysophyta
– Phaeophyta
Protista
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SAR/Stramenopila
• Subclade Bacillariophyta
– Diatoms
– Marine and freshwater
– Primary P/S member of
marine phytoplankton
• Chlorophyll, fucoxanthin
and beta-carotene
– Covered by glassy silica
shell
• 2 halves; pill box
• Diatomaceous earth
Protista
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SAR/Stramenopila
• Subclade Bacillariophyta
– Flagella in gametes only
– Mature forms move via secretion released
through grooves in shell
Protista
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SAR/Stramenopila
• Subclade Bacillariophyta
– Reproduction asexual and sexual
• Binary fission most frequent
Protista
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SAR/Stramenopila
• Subclade Chrysophyta
– Golden algae
– Freshwater or marine
– Mixotrophic
• P/S
– Chlorophyll, carotenoids,
fucoxanthin
• Heterotrophs when light too
low
– Glassy silica plates or scales
– May “bloom” in spring or fall
• Discolors water
Dinobryon: sessile, colonial
chrysophyte
Protista; photo: Frank Fox - http://www.mikro-foto.de;
http://creativecommons.org/licenses/by-sa/3.0/de/legalcode
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SAR/Stramenopila
• Subclade Phaeophyta
– Brown algae (color from olive green to brown)
– All multicellular
• Range from few centimeters to over 30m+ (giant kelps)
– Autotrophs
– Chlorophyll and fucoxanthin
– Cell wall contain cellulose and alginic acid
• Algin harvested for thickener in ice cream, pudding,
cosmetics
Protista
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SAR/Stramenopila
• Subclade Phaeophyta
– Large kelps look like plants
but different structure
• Holdfast
– Looks like roots, but only
anchor, no absorption
• Stipe
– Looks like trunk, minimal
vascular tissue
• Blade
– Looks like leaves
• Bladders
– Hollow, gas-filled for
buoyancy
Protista—picture: Claire Fackler; NOAA Photo Library
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SAR/Stramenopila
• Subclade Phaeophyta
– Reproductive cycle alternate haploid and diploid forms
Protista
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SAR
• Clade Alveolata
– Have alveoli (alvus = belly)
• Small flattened membrane vesicles just under cell
membrane (=pellicle)
• Support membrane
– Tubular membranes inside mitochondria
– 3 subclades
• Dinoflagellata
• Apicomplexa
• Ciliophora
Protista
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SAR/Alveolata
• Subclade Dinoflagellata
– Autotrophs or heterotrophs
• Many be mixotrophic
• Some have algal symbionts
– Plates (cellulose) form
“shell” under membrane
– Flagella beat within grooves
between plates
• Make cells spin
• Chloroplasts (P/S forms) have
chlorophyll and carotenoids
Protista
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SAR/Alveolata
• Subclade Dinoflagellata
– Members of marine
plankton
– Highly productive
Protista—picture: © Mona Hoppenrath; http://tolweb.org/Dinoflagellates/2445
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SAR/Alveolata
• Subclade Dinoflagellata
– Some live as symbionts
within other species
• Jellies, sea anemones, corals,
some sea slugs
• Dino’s in coral
– use waste CO2 and
nitrogenous wastes from
coral
– Supply 90% of corals food
– Provide color to corals
Protista—picture: © Toby Hudson;
http://commons.wikimedia.org/wiki/File:Coral_Outcrop_Flynn_Reef.jpg#mediaviewer/File:Coral_Outcrop_Flynn_Reef.jpg
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SAR/Alveolata
• Subclade Dinoflagellata
– Bioluminescence
– Red tides
• May be toxic to fish, sea
birds
Protista—picture: H. Hillewaert; http://en.wikipedia.org/wiki/Dinoflagellate
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SAR/Alveolata
• Subclade Apicomplexa
– Animal parasites
– Absorb nutrients across membrane
– Apical complex present at one end of cell
• Protein filaments, microtubles, organelles
• Function in attachment, invasion of host
– Ex: Plasmodium (malaria); Toxoplasma
(toxoplasmosis)
Protista
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SAR/Alveolata
• Subclade Apicomplexa
– Complex life cycle
• Sexual and asexual components
Protista—picture from
http://www.niaid.nih.gov/topics/Malaria/P
ages/lifecycle.aspx
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Life Cycle of Plasmodium
p. 595
SAR/Alveolata
• Subclade Ciliophora
– Marine, freshwater, soil
– Cilia
– Most heterotrophs
• Feed on bacteria and algae
Protista
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SAR/Alveolata
• Subclade Ciliophora
– Contractile vacuoles
– Gullet lined w/cilia for feeding
• Food vacuoles
• Waste vacuoles
– Trichocysts just under pellicle
• Discharge threads when stressed
Protista
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SAR/Alveolata
• Subclade Ciliophora
– Two nuclei
• Macronucleus polyploid
– Used in normal cell function
• Micronucleus diploid
– Used in reproduction (sexual or asexual)
Protista
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SAR/Alveolata
• Subclade Ciliophora
– Asexual reproduction via binary fission
• Both nuclei replicated and divide via mitosis
– Sexual reproduction
• Conjugation
– Cells pair up, form cytoplasmic bridge
– Replicate and exchange micronuclei
– 1 micronucleus forms macronucleus
– Cells undergo binary fission
Protista
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Conjugation in Paramecium
1
2
MEIOSIS
Diploid micronucleus
3
Macronucleus
DIPLOID
STAGE
HAPLOID
STAGE
4
Sexual
Reproduction
11
5
10
FUSION
9
8
7
6
Figure 27-7, p. 593
SAR
•
•
•
•
•
Clade Rhizaria
Amoebas
Stiff filamentous pseudopods
Many have tests (hard shells)
We’ll study 2 subclades
– Radiolaria
– Foraminifera
Protista
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SAR/Rhizaria
• Subclade Radiolaria
– 0.01mm to 1mm+
– Heterotrophs
• May contain algal
symbionts
– Marine
– Glassy internal skeleton
– Pseudopods supported
by microtubules
– Skeletons form
sediments, harden into
sedimentary rocks
Protista
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SAR/Rhizaria
• Subclade Foraminifera
– Forams
• 0.1 mm to 20 cm long
– Heterotrophs
• Some with algal symbionts
– Pseudopods supported by
needle-like spine
– Marine
– Some planktonic, most on
sandy bottoms and rocks
– Calcium carbonate internal
skeleton
• Form marine sediments
Protista
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Archaeplastida
• Closest relatives of land plants
• Plastids show no indication of secondary
endosymbiosis
• 2 Clades
– Rhodophyta
– Chlorophyta
Protista
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Archaeplastida
• Clade Rhodophyta
– Red algae
– Most marine, most free-living
– Multicellular, most small (<1 ft)
• Filamentous or sheetlike forms
• Some covered in calcium carbonate (coralline algae)
– Adhesive holdfast
Protista
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Archaeplastida
• Clade Rhodophyta
– Chlorophyll, phycobilins
• Phycobilins allow them to grow deeper than other
algae (absorb blue light)
– Complex life cycles involving alternation of diploid
sporophytes and haploid gametophytes
– Commercial use
• Porphyra used for nori
• Gelidium used for agar
• Chondrus, Gigartina, Eucheuma used for carrageenan
Protista
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Archaeplastida
• Clade Chlorophyta
– Green algae
– Most freshwater; some
symbionts
• w/fungi (=lichen), sea
anemones, marine snails
– Most microscopic
– Very diverse species
Protista
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Archaeplastida
• Clade Chlorophyta
– Green algae
– Most freshwater; some symbionts
• w/fungi (=lichen), sea anemones, marine snails
– Most microscopic
– Very diverse species
– Diverse life cycles
• Sexual, asexual, or alternate
– Chlorophyll, carotenoids
– Nucleic acid sequences, pigments, chloroplasts, food
reserves most similar to land plants
Protista
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Unikonta
• 2 Clades
– Amoebozoa
– Opisthokonts
• Closely related to Fungi and Animals
Protista
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Unikonta/Amoebozoa
• Most of the amoebas
and plasmodial slime
molds
• We’ll study 2 subclades
which aren’t plamodial
slime molds
– Gymnamoeba
– Entamoeba
Protista
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Unikonta/Amoebozoa
• Subclade Gymnamoeba
–
–
–
–
Amoebas
Marine and freshwater
Most free-living
Lobose pseudopods
• unsupported by internal
structure
• Locomotion and feeding
• No fixed body shape
– Contractile vacuole
Protista
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Unikonta/Amoebozoa
• Subclade Entamoeba
– Parasitic
– Entamoeba histolytica
• Amoebic dysentery
– Destroys cells lining intestine
– Ulcerations, cramps, bloody
diarrhea, foul-smelling stools
– Cysts spread through
contaminated food or water
– A leading cause of death in
infants and small children in
less developed nations
Protista; photo CDC.gov
Trophozoite with ingested RBCs
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Unikonta/Opisthokonts
• Nucleariida
– DNA evidence indicates
close relationship to
Fungi
Protista; photo by
NEON ja; https://creativecommons.org/licenses/by-sa/2.5/legalcode
57
Unikonta/Opisthokonts
• Choanoflagellida
– DNA evidence indicates
close relationship to
Animalia
Protista; photo lower left by DH Zanette;,public domain,
https://en.wikipedia.org/wiki/Choanoflagellate#/media/File:Sphaeroeca-colony.jpg; photo upper right by Stephen
Fairclough, https://creativecommons.org/licenses/by-sa/2.5/legalcode; picture lower right by Wikipedia user Urutseg,
https://creativecommons.org/licenses/by-sa/3.0/legalcode;
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