Protists

Protists belong to the Kingdom Protista, which includes mostly unicellular organisms that do not fit into the other kingdoms.

Characteristics of Protists

• mostly unicellular, some are multicellular (algae)
• can be heterotrophic or autotrophic
• most live in water (though some live in moist soil or even the human body)
• ALL are eukaryotic (have a nucleus)
• A protist is any organism that is not a plant, animal or fungus

Protista = the very first

Classification of Protists

• how they obtain nutrition
• how they move

Animallike Protists - also called protozoa (means "first animal") - heterotrophs
Plantlike Protists - also called algae - autotrophs
Funguslike Protists - heterotrophs, decomposers, external digestion

.Animallike Protists: Protozoans

Four Phyla of Animallike Protists

Classified by how they move

• Zooflagellates - flagella
• Sarcodines - extensions of cytoplasm (pseudopodia)
• Ciliates - cilia
• Sporozoans - do not move

Zooflagellates

move using one or two flagella
absorb food across membrane

Leishmania

Sarcodines

Ameba (See Ameba Coloring Sheet)

moves using pseudopodia ( "false feet" ), which are like extensions of the cytoplasm --ameboid movement
ingests food by surrounding and engulfing food (endocytosis), creating a food vacuole
reproducing by binary fission (mitosis)
contractile vacuole - removes excess water
can cause amebic dysentery in humans - diarrhea and stomach upset from drinking contaminated water
Other sarcodines: Foraminferans, Heliozoans

Ciliates

Paramecium (See Paramecium Coloring Sheet)

move using cilia
has two nuclei: macronucleus, micronucleus
food is gathered through the :mouth pore, moved into a gullet, forms a food vacuole
anal pore is used for removing waste
contractile vacuole removes excess water
exhibits avoidance behavior
reproduces asexually (binary fission) or sexually (conjugation)
outer membrane -pellicle- is rigid and paramecia are always the same shape, like a shoe

Pond Life Video Gallery

Sporozoans

do not move on their own
parasitic
Malaria is a sporozoan, infects the liver and blood

 

More Notes

Animallike Protists and Disease
Plantlike Protists: Unicellular Algae