Page 7 - Kingdom Protist

Animal-like Protists PART 2

Objectives “Protozoa” is a general term for all the

• Identify the "animal like" unicellular or colonial eucaryotic
characteristics of animal
organisms of the Kingdom Protista. These
like protist.
organisms in general lack cell walls, are
• Describe the structures
and organelles of heterotrophs, and are mostly motile organisms.
While not animals themselves, biologist believe
protozoans_ animal like
protist. these simple kinds of organisms gave rise to the
• Explain the life cycles of kingdom of animals.

protozoans_ animal like
protist. General Characteristics of animal-like protists:
a. Single celled organisms, some colonial

Review Vocabulary b. No cell wall but some secrete a "shell" of silica
hypotonic: the concentration or calcium carbonate or a flexible pellicle
of dissolved substances is c. Mostly heterotrophs

lower in the solution outside d. Many with specialized organelles for a variety
the cell than the of functions
concentration inside the cell. e. Move by flagella, cilia, pseudopodia, or are

non motile
f. Inhabit a diverse array of habitats and include
New Vocabulary
freshwater and marine forms to soil dwelling,
pellicle symbiotic and parasitic forms.
trichocyst
g. Some, particularly the parasitc forms, have
contractile vacuole
complex life cycles
pseudopod
test h. Extensive fossil record.

Ciliophora

One of the characteristics that biologists use to further classify protozoans into

different phyla is their method of movement. Members of the phylum Ciliophora, also

known as ciliates are animal-like protists that have numerous short, hairlike
projections. Some ciliates have cilia covering their entire plasma membrane, while

others have groups of cilia covering parts of their membrane, as shown in Figure 12.

Note that the Stentor’s cilia are located on the anterior end, they help propel food

into the cell. There are more than 7000 species of ciliates. They are abundant in most
aquatic environments ocean waters, lakes, and rivers. They also are found in mud,
and it is estimated that as many as 20 million ciliates can inhabit one square meter in

some mudf lats.
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