WARM-UP:
What molecule is split during the light
reaction of photosynthesis?
KINGDOM PROTISTA
Eukaryotic - most unicellular; complicated internal structure.
• Divided by mode of nutrient acquisition
•plant-like: autotrophic; algae (including seaweed), diatoms
•animal-like (aka protozoa) – heterotrophic; internal digestion.
Some parasitic (malaria)
•Further classified by motility.
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Flagellated (Giardia), Euglena has characteristics of plant & animal
• Ciliated (Paramecia, Euplotes)
• Amoeboid (amoeba species) – use pseudopods or “false feet”
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fungus-like (slime molds, etc.) – heterotrophic with absorptive
(external) digestion. Includes many common plant pathogens such as
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Phythophthora, cause of the Irish Potato famine
ANIMAL-LIKE PROTISTS: PROTOZOA
COMMON EXAMPLES INCLUDE PARAMECIA AND AMOEBA
ANIMAL-LIKE PROTISTS:
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Most are free-living. These
are classified by movement:
amoeba-like, ciliated, or
flagellated.
Zoomastigina - flagella
Ciliophora - cilia
Sarcodina - pseudopods
Sporozoa - Non-motile
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Some are parasitic.
Ex: Plasmodium which causes
malaria. See life cycle page 503
in textbook.
AMOEBAS IN ACTION
ANIMAL-LIKE PROTISTS: CILIATED
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Cilia beat in a synchronized
pattern to cause
movement.
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Example: Paramecium
Paramecium is a typical
ciliate. It has a gullet to
swallow food, and a
contractile vacuole to get
rid of excess water.
Genetics: the DNA used for
sexual reproduction is
stored in the small
micronucleus. A copy of
this information is used to
run the cell.
ANIMAL-LIKE PROTISTS: FLAGELLATED
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Flagellates with long
whiplike hairs that propel
the cell.
Some nasty parasites are
flagellates, including –
*Giardia lamblia, which causes
diarrhea and is found in most
surface waters of the US.
*Trypanosoma brucei, which
causes sleeping sickness in
Africa.
*Trichimonas vaginalis, an STD
ANIMAL-LIKE PROTISTS: SPOROZOANS
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Non-motile animal-like
protists
Live part of their life cycle
inside the cells of hosts;
ie, parasitic
Ex: Plasmodium which
causes malaria which kills
1-2 million people each
year.
Mosquitoes are the vector.
Plasmodium reproduces
sexually in mosquito gut and
asexually inside the human
red blood cells, destroying
them as they leave.
PLANT-LIKE PROTISTS
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Commonly called ALGAE.
Many different pigments affect color.
Rhodophyta is red, chrysophyta is gold.
Green algae are haploid most of their
life cycle, with only a very short diploid
phase.
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Autotrophs. Most of the oxygen we
breathe came from algal photosynthesis.
Very important commercial uses.
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Called “alternation of generations:
Thickener (algin)
Most are single-celled, but a few form large
multicellular seaweed species. Some used in
food preparation (sushi, agar)
Some (like diatoms)have calcium
carbonate (chalk) or silica shells.
Important
applications for
gardeners
MULTICELLULAR ALGAE
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commonly called seaweed
can be classified as red, brown, and
green algae. All have chloroplasts,
but the pigments in the chloroplasts
vary, giving the different colors.
Some, like kelp, are very large and
contain several different types of
cells and tissue. These include
leaves for photosynthesis, gas-filled
bladders for buoyancy, the root-like
holdfast, and tubes to transport
nutrients throughout the body.
Algae contain the polysaccharide
“agar”, which is tasteless and is
used to thicken foods such as soft
ice cream.
EUGLENA: THE MISSING LINK??
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Has features of a
plant … chloroplasts
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Allows it to make its
own food
Has features of an
animal …
“eyespot” to detect
light vs dark
 “flagellum” allows it to
move
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FUNGUS-LIKE PROTISTS
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Include water molds and slime molds
Heterotrophic; many are decomposers of
dead organisms.
Unlike fungi, the fungus-like protists
produce motile (moving) cells during part
of their life cycle. Also, these protists
surround and engulf bacteria as food.
Slime molds live as separate cells most
of their lives, feeding on bacteria. When
conditions get harsh, they aggregate into
a multicellular slug, which migrates to a
new location. The slug then forms a
fruiting body that generates spores. The
spores from the fruiting body are very
hardy.
Multinucleate plasmodium. Resembles
animals in that it is motile and
engulfs its food.
PHYSARUM POLYCEPHALUM (SLIME MOLD)
FUNGUS-LIKE PROTISTS
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Include some of the worst plant
diseases (downy mildew, etc.)
Phytphthora infestans causes
rot in plants. In the 1840’s,
Phytophthora caused the potato
blight in Ireland.
Caused crop failures over
several years, resulting in
famine, death and emigration.