Protista is one kingdom in the
domain Eukarya.
• Protists are difficult to classify.
Protists can be animal-like,
plantlike, or funguslike.
• Protists are eukaryotes that are not
animals, plants, or fungi.
• Protist classification will likely change.
– Some protists are not closely related.
– Molecular evidence supports reclassification.
• Animal-like protists are called protozoans.
– heterotrophs (consume other organisms)
– single-celled
– Can move independently
Animal-like protists move in
various ways.
macronucleus
contractile vacuole
food vacuole
oral groove
micronucleus
cilia
• Protozoa with flagella are zooflagellates.
• flagella help zooflagellates swim
– more than 2000 zooflagellates
• Protists that move with pseudopods are
called pseudopodia.
– some change shape as they move
– ex. Amoebas and foraminifera
Amoeba
foraminiferian
• Protozoa that move with cilia are called
ciliates.
–Cilia has 2 functions: 1. movement, 2. feeding: food is
swept into the oral groove by the cilia for digestion.
–Macronucleus-controls cells non-reproductive functions
such as metabolism and homeostasis.
–Micronucleus-reproductive division
– more than 8000 ciliates
macronucleus
Ex. paramecium
contractile vacuole
food vacuole
oral groove
micronucleus
cilia
Animal-like protists cause disease are
called sporozoans
• Malaria is caused by
Plasmodium and spread
by mosquitoes.
• Sleeping sickness is
caused by Trypanosoma
and spread by flies.
• A giardia infection
(vomiting and diarrhea)
is caused by Giardia and
spread through water.
human liver
sporozoites
liver cells
developed
parasites
red blood
cells
Malaria Infection
• Plantlike protists are called phytoplankton.
– photosynthetic
– single-celled, colonial, or multicellular
– no roots, stems, or leaves
• Plantlike protists that exhibit some animal
characteristics are called euglenoids.
– mostly
photosynthetic, some
also heterotrophic
pellicle
– single-celled
– one or two flagella
nucleus
–first evolutionary
organism with primitive
eyespot, used to detect
light for photosynthesis
contractile
vacuole
flagellum
chloroplast
eye spot
• Dinoflagellates are mostly marine plantlike
protists.
– have two flagella
– may be bioluminescent
– have stiff protective
plates
– can cause red tide,
algal blooms that can
cause harm to aquatic
life and humans by
releasing toxins and
removing
oxygen/nutrients from
water.
Dinoflagellates
• Diatoms are plantlike protists with
glasslike shells.
– shells made of silica
– produce large amounts of oxygen
–Non-mobile
Plantlike protists can be singlecelled or multicellular.
• Photosynthetic plantlike protists are
called algae.
• Ex. is the Volvox
– Flagella on inside
– Live in colonies
colony
daughter colony
• Multicellular algae are classified by their
pigments.
– Green algae contain
chlorophyll a and b.
–May be single-celled,
colonial or multicelled.
–Ex. common algae seen on
ponds and lakes, seaweed.
–Red algae contain
chlorophyll a and
phycoerythrin.
–Ex. help build coral reefs
– Brown algae contain
chlorophyll c and fucoxanthin.
–Ex. kelp, can grow up to 60
meters in height.
Human Uses for Algae
• Major food source for the ocean.
• Produces much of the earth’s oxygen.
• Chemicals from algae are used to make plastics,
waxes, paints, deodorants, agar etc.
• Also found in ice cream, pancake syrup,
eggnog, etc.
Many plantlike protists can reproduce
both sexually and asexually.
• All algae can reproduce asexually.
– Multicellular algae can fragment.
– Chlamydomonas divides into zoospores.
• Some algae produce sexually.
– Some species alternate generations(have both
asexual and sexual reproductive cycles).
– Sexual reproduction can be triggered by environmental
stress.
• Funguslike protists decompose dead
organisms.
– Heterotrophs, called decomposers
– can move, whereas fungi cannot
Funguslike protists
•Decompose organic material
• Slime molds and water molds have both fungus-like and
animal-like traits.
– decomposers, like fungi, (beneficial help material rot).
– can move, like animals
• Slime molds can be plasmodial or cellular.
– Plasmodial slime molds (acellular) are giant cells with
many nuclei.
–Cellular slime molds contain independent cells.
• Water molds are freshwater, funguslike
protists.
– one type of water mold caused Great Potato Famine
of Ireland in the 1800’s (potato blight, blights of
grapes and tomatoes)
– made of branching
strands of cells
– can be parasites of
plants or fish
Overview Chart of Protista
Phylum
Life Cycle
Motility
Habitat
Chlorophyta
(green algae)
Zygotic
Gametic and alt of
generation
Some motile &
Nonmotile
Fresh water, Few Marine &
Terrestrial
Bacillariophyta
( diatoms)
Gametic
flagellum
Marine & fresh
phaeophyta
(brown algae)
Gametic
Flagellum
Marine & fresh
Alternation of Generation
Nonmotile
Mostly Marine & few fresh
water
Rhodophyta
(Red Algae)