Prostista Kingdom
What is a Protist?
Protists are organisms that are classified into the kingdom Protista. The protists form a group of organisms that really do not fit into any other kingdom. Although there is a lot of variety within the protists, they do share some common characteristics.
All protists are eukaryotic. That is, all protists have cells with nuclei. In addition, all protists live in moist environments.
Protists can be unicellular or multicellular. Protists can be microscopic or can be over 100 meters (300 feet) long. Some protists are heterotrophs, while others are autotrophs.
Since protists vary so much, we will group them into three subcategories: animal-like protists, fungus-like protists, and plant-like protists.
Animal-like Protists
Protists that are classified as animal-like are called protozoans and share some common traits with animals. All animal-like protists are heterotrophs. Likewise, all animal-like protists are able to move in their environment in order to find their food. Unlike, animals, however, animal-like protists are all unicellular.
Animal-like protists are divided into four basic groups based on how they move and live.
Animal-like Protists
Protists with flagella
The Giardia is another example of this type of animal-like protist.
These protists move by beating their long whiplike structures called flagella. These protists can have one or more flagella that help them move. Many of these protists live in the bodies of other organisms. Sometimes, they help their host, while at other times they harm their host.
Protists with pseudopods
These protists move by extending their bodies forward and then pulling the rest of their bodies forward as well. The finger-like structures that they project forward are called pseudopods. The pseudopods are also used to trap food.
Parasitic protists

These protists are chartacterized mainly by the way they live. All of these protists are parasites. Many of these protists cause diseases such as malaria.
Protists with cilia
These protists move by beating tiny hair-like structures called cilia. The cilia act as tiny oars that allows the protist to move through its watery environment. The cilia also help the protists capture food.

Protozoans - "Animal-like" protista
All Those members of the protista kingdom which act like animals
Cannot make their own food
Most display a great deal of movement
Possess many "Animal-like" characteristics
Particularly movement
Some cannot make their own food
Many relationships from - free living, parasitic, saprophytic, mutualistic
Often classified by how they move
Amoeba - moves with Pseudopods (false feet)
Paramecium - moves with cilia
Flagellates - move like the Euglena flagellum
Sporozoans - produce spores

Trypanosoma Amoeba

Plasmodium Paramecium

Fungus-like Protists
Fungus-like protists are heterotrophs with cell walls. They also reproduce by forming spores. All fungus-like protists are able to move at some point in their lives. There are essentially three types of fungus-like protists: water molds, downy mildews, and slime molds.

Fungus-like Protists

Heterotrophic, amoeboid mass called plasmodium

Heterptrophic, separate cells
Plasmodial slime mold

Cellular slime molds
Live in moist soil and on decaying plants and trees;
Very colorful
Move by forming pseudopods
Feed on bacteria and

Heterotrophs with cell walls,
reproduce by forming spores,
able to move at some point in their lives
Live in water or moist environments
Look like tiny threads with a fuzzy covering
Attack food such as potatoes, cabbage, and corn and can destroy whole crops
Heterotrophs with cell walls,
reproduce by forming spores,
able to move at some point in their lives
Live in water or moist environments
Look like tiny threads with a fuzzy covering
Attack food such as potatoes, cabbage, and corn and can destroy whole crops

Fungus Like Protists

All Those members of the protista kingdom which act like fungus
Small group
Often brightly colored
Slime Molds
Change form during life cycle
Tend to live in damp locations
Slime Molds
The three stages are similar to that of other organisms.

Plasmodial Slime Mold

Cellular slime molds

Water Mold Downy Mildew

Plant-like Protists
Plant-like protists are autotrophic. They can live in soil, on the bark of trees, in fresh water, and in salt water. These protists are very important to the Earth because they produce a lot of oxygen, and most living things need oxygen to survive. Furthermore, these plant-like protists form the base of aquatic food chains.

These plant-like protists can be unicellular, multicellular, or live in colonies. The plant-like protists are divided into three basic groups: euglenoids, diatoms / algae and dinoflagellates

Plant-like Protists
Unicellular, photosynthetic, single flagellum

Autotrophs when sunny
Heterotrophs when dark
Found mostly in fresh water
Some have flagellum

Unicellular, photosynthetic, chlorophyll a and c

Glasslike cell walls
Used in toothpastes, scouring products, and as filters

Green Algae

Are green in color
Mostly unicellular, but some form colonies, and a few are multicellular
Live in fresh water, salt water, and a few live on land

Red Algae
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

Brown Algae
Commonly called sea weed
Have large leaf-like structures called blades
Have air-filled sacs called air bladders
Have root-like structure called holdfast
Live in salt water
Are used by humans to help make pudding and salad dressing

Unicellular, two spinning flagella, chlorophyll a and c

Covered by stiff plates
Have two flagella
May glow in the dark
Found in ocean


Golden Brown Algae


Sporozoans - produce spores
Passive movement (none)
The organism which causes Malaria

Plasmodium Life Cycle
Life Cycle


autotroph: an organism that can make its own food

bacteria: a prokaryoticmicroorganism

cilia: small hair-like projections used for movement and to obtain food by ciliate protozoans

colony: a group of individual organisms living together

decomposer: organisms that eat decaying materials and help to return necessary elements to the environment

eukaryotic: a cell with a nucleus

flagella: tiny whiplike structures used in movement and feeding in flagellate protozoans (flagellum is the singular form)

heterotroph: an organism that feeds on other organisms

host: the organism on which a parasite lives

malaria: a disease spread when healthy misquitoes bite people and transfer the protist Plasmodium into the
person; the disease is characterized by high fevers that alternate with severe chills

microorganism: an organism that cannot be seen without the use of a microscope

multicellular: composed of more than one cell

parasites: an organism that lives in or on another organism; may be harmful, helpful, or indifferent to host

prokaryotic: a cell without a nucleus

protozoans: animal-like members of the kingdom Protista

pseudopod: "false foot"; a structure used by amebas and slime molds for movement

spore: tiny cell that can grow into an organism

unicellular: composed of only one cell

Mastigophora / Tripanosoma

Flagellates - move like the Euglena

Often have more than one flagellum
The organism which causes African sleeping sickness - carried by the testie fly
Some live in the digestive tracts of termites and assist in the digestion of cellulose.

Giardia Anatomy and Life Cycle

Giardia intestinalis (syn. Giardia lamblia)
Cysts are resistant forms and are responsible for transmission of giardiasis. Both cysts and trophozoites can be found in the feces (diagnostic stages) (1) . The cysts are hardy and can survive several months in cold water. Infection occurs by the ingestion of cysts in contaminated water, food, or by the fecal-oral route (hands or fomites) (2) . In the small intestine, excystation releases trophozoites (each cyst produces two trophozoites) (3) . Trophozoites multiply by longitudinal binary fission, remaining in the lumen of the proximal small bowel where they can be free or attached to the mucosa by a ventral sucking disk (4) . Encystation occurs as the parasites transit toward the colon. The cyst is the stage found most commonly in nondiarrheal feces (5) . Because the cysts are infectious when passed in the stool or shortly afterward, person-to-person transmission is possible. While animals are infected with Giardia, their importance as a reservoir is unclear.

Geographic Distribution:
Worldwide, more prevalent in warm climates, and in children.

Amoeba Feeding

Amoeba Anatomy

Phylum Sarcodina

Pseudopods (false feet) projections of cytoplasm.
Some surrounded by a calcium "shell"
Amoeba has no definite shape
Amoeba Parts
Food Vacuole
Cell membrane
Amoeba Feeding
Amoeba Movement
Shape is constantly changing
Food is surrounded by pseudopods and stored in a food vacuole
Amoeba Movement and Feeding
Amoeba Reproduction
Asexual reproduction
Pseudopods start pulling apart
Nuclear material replicates itself
Pseudopods pull apart splitting the cell
The nucleus splits
Two smaller cells result

Paramecium Anatomy

Moves using cilia - short hairs lining cell


Paramecium Parts
Macro nucleus
Food Vacuole
Contractile Vacuole
Oral Groove
Cell membrane

Other Ciliophora


Paramecium Reproduction

Asexual reproduction
Nuclear material replicates itself
Nuclear material splits itself
Cell starts pulling apart
Two smaller cells result


All Those members of the protista kingdom which act like plants
Algaes are also found in the Moneran and Plant kingdoms
Possess more "Plant-like" characteristics
Other "algaes" are grouped with the monerans and others with plants.
Vary in color and often named by its color.
Most live in water, some on damp surfaces
Make up a large part of the plankton of the oceans
All algae contain chlorophyll and carry on photosynthesis

Euglenoid Anatomy

Most are unicellular
Possess movement like animals
Move by using whip like tail called flagellum (one only)
Example Euglena
Reproduces asexually

Euglenoid Parts
Eye spot
Cell membrane

Dinoflagellate Anatomy
Covered by stiff plates
Have two flagella
May glow in the dark
Found in ocean

Dinoflagellates - Pyrophyta

Surrounded with "plates"
Has two flagella
Phosphorescent algae
Responsible for "red tides"
Contains toxins

Diatom Anatomy

Diatoms - Chrysophyta (golden algae)

Golden brown algae
Two part shell of silicon (glass)
Food stored as oil
Responsible for most oil consumed today
Diatom Parts

Research Links

Cells Alive

Protist Image Data