PROTISTS
• Protists include the
most complex singlecelled organisms on
Earth.
• Long ago, microscopic
one celled protists
(nummalitids) lived in
oceans. Their shells
were the size of a coin.
• When they died, over
time their shells turned
into limestone, which
many years later were
used to build the great
pyramids of Egypt.
PROTISTS ARE A DIVERSE
GROUP OF ORGANISMS
• MOST PROTISTS ARE SINGLE-CELLED
• PROTISTS GET THEIR ENERGY IN 3 WAYS
(sunlight, eating other organisms & absorbing
nutrients/materials from environment)
Most Protists single-celled
• Anoton van Leeuwenhoek looked at pond water
(with early microscope) and saw “little
animacules” or protists.
• Protists = all organisms with cells having nuclei
& not in animal, plant or fungi kingdom. (most
single celled but some have many cells with
simple structures)
• Algae is protists that use sunlight as energy
source (both single & multi-cellular). Seaweed
(like kelp growing over 100m) and diatoms are
types of algae. Slime molds are also a mulitcellular protist. Euglena = sinlge cell protist.
• Protists live in any moist environment (fresh &
salt water, & forest floor).
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Protists Get Energy In 3 Ways
Capture sunlight and convert it to usable energy.
Eat other organisms to obtain energy
Absorb materials & nutrients form its environment.
Euglena (single-celled protist) can switch modes:
swim through ponds to absorb nutrients, or use
sunlight to make own food
PHOTOSYNTHESIS PROTIST
• ALGAE: get energy from sunlight; have
chlorophyll like plants to do this. Take in H2O &
CO2 to make food & release O2 (photosynthesis)
DIATOMS are an ex.
• VOLVOX: a bunch of algae cells living together
in a hollow ball as a colony (simplest type of
multicellular organism)
• PLANKTON: all organisms that drift in water:
includes young of many animals, some adult
animals & protists. If perform photosynthesis,
called phytoplankton (include algae &
cyanobacteria). Phytoplankton live in all oceans
& PRODUCE MOST OF OYGEN ANIMALS
BREATHE!
EATING PROTISTS
• PROTOZOA: single celled protists that eat other
organisms, or decaying parts of other organisms.
Paramecium swim rapidly using hairlike cilia.
• Another group of protozoa use long whiplike tails
called flagella.
• Some others are very flexable (amoebas) and ooze
along surfaces.
• Many protists are parasites which cause disease like
malaria. Due to protist living in mosquito that
transfers to humans if bitten. It then goes through a
life cycle that destroys red blood cells.
DECOMPOSER PROTISTS
• Protists that absorb food from their environment
can be called funguslike protists. Take in
materials from soil or other organisms & break
down materials to get energy. Are called
DECOMPOSERS.
• Mold: make fuzzy like growth. Most are fungi
(like bread mold) but are 3 types that are Protists:
• Water Mold: funguslike protist living mostly in
fresh water; form fuzzy growth on food
SLIME MOLDS: live on decaying plants on forest
floor. Starts out eating bacteria as single cell.
Then when food is scarce, clump together as
multicellular colony absorbing nutrients. Finally,
form reproductive structure to release spores into
the air
DECOMPOSER PROTISTS
CONTINUED
• Plasmodial slime mold: one giant cell with
many nuclei. Looks like fine net, usually
found on rotting logs.