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

Phylum	Characteristics	Example	Description
Mastigophorans	Protists with flagella	Trypanosoma The Giardia is another example of this type of animal-like protist. Giardia Anatomy	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.
Sarcodines	Protists with pseudopods	Amoeba Anatomy	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.
Sporozoa	Parasitic protists	Plasmodium Sporozoans Life Cycle	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.
Ciliates	Protists with cilia	Paramecium Anatomy	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

Protozoans

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

Phylum	Characteristics	Example	Description
Myxomycota Acrasiomycota	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 other microorganisms.
	Heterotrophs with cell walls, reproduce by forming spores, able to move at some point in their lives	Water Molds	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	Downy Mildews	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

Myxomycota

Multicellular

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

Phylum	Characteristics	Example	Description
Euglenophytes	Unicellular, photosynthetic, single flagellum	Euglena Euglenoid Anatomy Euglenoid Parts	Autotrophs when sunny Heterotrophs when dark Unicellular Found mostly in fresh water Some have flagellum
Chrysophytes	Unicellular, photosynthetic, chlorophyll a and c	Diatoms / algae Diatom Anatomy	Unicellular Glasslike cell walls Used in toothpastes, scouring products, and as filters
		Green Algae 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	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
		Brown Algae	Multicellular 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
Dinoflagellates	Unicellular, two spinning flagella, chlorophyll a and c	Gessnerium Dinoflagellate Anatomy	Unicellular Covered by stiff plates Have two flagella May glow in the dark Found in ocean

Euglena

Diatoms

Golden Brown Algae

Dinoflagellates

Sporozoans - produce spores

Sporozoans

Passive movement (none)

The organism which causes Malaria

Plasmodium Life Cycle

Life Cycle

VOCABULARY:

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

Mastigophora

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

Nucleus

Pseudopods

Food Vacuole

Cell membrane

Amoeba Feeding

Pseudopods

Amoeba Movement

Pseudopods

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

Paramecium

Moves using cilia - short hairs lining cell

Ciliophora

Paramecium Parts

Macro nucleus

Micronucleus

Cilia

Food Vacuole

Contractile Vacuole

Oral Groove

Cell membrane

Other Ciliophora

Stentor

Vorticella

Spinostomium

Paramecium Reproduction

Asexual reproduction

Nuclear material replicates itself

Nuclear material splits itself

Cell starts pulling apart

Two smaller cells result

Algae

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

Euglenoids

Most are unicellular

Possess movement like animals

Move by using whip like tail called flagellum (one only)

Example Euglena

Reproduces asexually

Euglenoid Parts

Nucleus

Chloroplasts

Flagellum

Eye spot

Cell membrane

Dinoflagellate Anatomy

Unicellular

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 http://www.cellsalive.com/

Protist Image Data http://megasun.bch.umontreal.ca/protists/protists.html