Protists
Protist Characteristics
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An extremely diverse
group
Eukaryotes
Mostly unicellular
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some colonial
some multicellular
Some heterotrophic,
some autotrophic, some
both
Some have cell walls
3 Major Types
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Animal-like
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protozoa
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Fungus-like
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Plant- like
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algae
“Animal-Like” Protists
Protozoans
Are heterotrophs (some are parasites!)
Types of protozoans:
1. sarcodines
2. ciliaphore
3. flagellates
4. sporozoans
Protist Phyla
1. Sarcodines – use
pseudopodia (“false
feet”) to move and
get food
EX: Amoebas, foraminifera.
radiolarians
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http://www.funsci.com/fun3_en/protists/exhibi
tion.htm
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Amoeba change forms continuously
2. Ciliophores –
use cillia to move
EX: paramecium
http://www.funsci.com/fun3_en/protists/exhibi
tion.htm
 Paramecia
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http://ebiomedia.com/gall/ciliates/index.html more ciliates
3. Flagellates- have whip-like flagella
This flagellate lives in termite gut –
digests cellulose.
This one is a pathogen –
causes diarrhea
EX: Giardia
Dinoflagellates have 2 flagella
A related protist, Leishmania, causes the
disease leishmaniasis.
These protists are transmitted by biting flies,
and are a serious public health problem in
much of the world.
Leishamanasis
4. Sporozoans – no method of movement
form spores, many are parasites
EX:
- Toxoplasma- carried by rodents, birds, and
domestic cats (can be harmful to unborn babies if
mom changes the kitty litter box)
- Plasmodium- causes Malaria (carried by
mosquitoes)
Life Cycle of Malaria
“Plant-like” protists
Are autotrophs
Mostly algae
Are classified by their pigments (their color) –
red, green or brown
Many are multicelled
Do not have stems, leaves and roots like plants
Make up phytoplankton (bottom of ocean food
chain)
Plant like protists
1. Green Algae
Are green in color
 Ex –
Spirogyra
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Spirogyra
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http://www.funsci.com/fun3_en
/protists/exhibition.htm
Desmid- unicellular green algae
Green algae - Volvox
Green algae - Haematococcus
Turns birdbath red
2. Red Algae
Multicellular
 Commonly called sea weed
 Live in deep salt water
 Are used by humans to help make ice cream
and hair conditioner
 Are eaten in some Asian cultures
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3. Brown Algae
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Multicellular
Commonly called sea weed
Thallus- plant-like seaweed
body
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Holdfast- root-like; anchors to
surface
Stipe- stem-like
Blades- leaf-like
Have air-filled sacs called air
bladders
Used in many foods and
beauty products
Diatoms
Photosynthetic protists
 Mostly marine
 Have silica (glass-like)
shell
 Used to make
reflective paint,
toothpaste, and
abrasives
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“Fungus-Like” Protists
Slime & water molds
Some of these can move
Many are decomposers or parasites
Slime molds