Question

Describe briefly the four major groups of Protozoa.

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Answer 1

Answer:

Protozoans are unicellular, microscopic eukaryotes..

• Protozoas are unicellular, microscopic eukaryotes.
• All protozoans are heterotrophic.
• Some are free living, others infect higher animals and function as parasites.
• They reproducesmainly through binary fission however exceptions exist.
• They have a holozoic mode of nutrition. (Holozoic means food from the outside has to be ingested and internally broken down for the body to be able to utilise it.)There are four major groups of protozoans:

Amoeboid protozoas: (example: Amoeba)

• They can be found in fresh water, moist soil and sea water.
• They move with the help of psuedopodia.
• They do not have a periplast (a type of membrane)
• They maybe free living or parasitic.

.Ciliated protozoas: (example: Paramecium)

• They are aquatic.
• Their bodies are covered by tiny hair like structures called cilia.
• They use their cilia for movement and for caputuring their prey.
• They have an outer cavity on their cell surface.

.Flagellated protozoas: (example: Trypanosoma)

• These protozoans are either free living or parasitic
• They possess a flagellum.
• They use the flagellum for locomotion.

.Sporozoas: (Example: Plasmodium)

• These protozoans have an infective spore-like stage.
• All of them are parasitic
• They have an elaborate life cycle involving more than one host.
• They do not possess any cilia or flagella.