Bio1309 – Protista
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So Just What is a Protozoan?
• Eukaryotic
• Single cell-organism
• Free living or parasitic
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Here are a couple:
Paramecium!
Amoeba!
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More about Protozoa
• Complex structure and function
– Ectoplasm and endoplasm
– Pseudopods, flagella, cilia
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Complex structure associated with the protozoa Trichomonas
vaginalis.
Structure of a typical mastigophoran
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Where do they live?
• fresh water and soil
• Inside other organisms as parasites
– They are all Heterotrophs!
Trypanosomes
In blood
Malaria inside RBCs
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Are They Important?
Yes! Yes!
They are an important part of aquatic and
soil ecosystems…
They are important as disease causing
organisms! (ugggh!)
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What kinds are there?
• Sarcodina
move w/ pseudopod, like amoebas
• Ciliophora
move by cilia, like paramecium
• Zoomastigina or Mastigophora
move by flagella, like trypanosomes
• Sporozoa
immobile and parasitic, like malaria
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A Sarcodine
• The Amoeba!
pseudopods
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A Ciliate
• Paramecium!
What a “hairy” guy –
a million cilia for movement
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Mastigophora
• Trichomonas vaginalis – an STD!
Yes- we have flagella!
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A Sporozoan
• Plasmodium sp. (Malaria!)
Parasitic!!
We don’t move, but we don’t have to!
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Protozoan Sex?
• Mostly asexual
• sexual phase only in ciliates, the
apicomplexans, and some flagellates
and sarcodines
• Sometimes its just conjugation
• Most can do the Trophozoite  cyst
dance!
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Typical life cycle for protozoa
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Medically important protozoa
• Amoeboid protozoa
– Causes brain infections
• Flagellated protozoa
– Example: Giardiasis
• Apicomplexan protozoa
[organelle called an apical complex]
– Example: Malaria
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Pathogenic amoebas, and nonpathogenic shelled amoebas
Examples of sarcodinians
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Ciliated protozoa, generally free-living and harmless
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Cycle of protozoan transmission:
can include the protozoa, host and vectors, often a complex life
cycle.
Transmission in Schistosoma sp. infection. Thanks to CDC.
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Stages of development and transmission amoebic dysentery in the human host.
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