Describe
briefly the four major groups of Protozoa.
Describe briefly the four major groups of Protozoa.
Protozoa
are microscopic unicellular protists with heterotrophic mode of
nutrition. They may be holozoic, saprobic, or parasitic. These are
divided into four major groups.
(1) Amoeboid
protozoa or sarcodines
They
are unicellular, jelly-like protozoa found in fresh or sea water and
in moist soil. Their body lacks a periplast. Therefore, they may be
naked or covered by a calcareous shell. They usually lack flagella
and have temporary protoplasmic outgrowths called pseudopodia. These
pseudopodia or false feet help in movement and capturing prey. They
include free living forms such as Amoeba
or parasitic forms
such as Entamoeba.
(2) Flagellated
protozoa or zooflagellates
They
are free living, non-photosynthetic flagellates without a cell wall.
They possess flagella for locomotion and capturing prey. They include
parasitic forms such as Trypanosoma,
which causes sleeping sickness in human beings.
(3) Ciliated
protozoa or ciliates
They
are aquatic individuals that form a large group of protozoa. Their
characteristic features are the presence of numerous cilia on the
entire body surface and the presence of two types of nuclei. All the
cilia beat in the same direction to move the water laden food inside
a cavity called gullet. They include organisms such as Paramoecium,
Vorticella,etc.
(4) Sporozoans
They
include disease causing endoparasites and other pathogens. They are
uninucleate and their body is covered by a pellicle. They do not
possess cilia or flagella. They include the malaria causing parasite
Plasmodium.
Protozoa are microscopic unicellular protists with heterotrophic mode of nutrition. They may be holozoic, saprobic, or parasitic. These are divided into four major groups.
(1) Amoeboid protozoa or sarcodines
They are unicellular, jelly-like protozoa found in fresh or sea water and in moist soil. Their body lacks a periplast. Therefore, they may be naked or covered by a calcareous shell. They usually lack flagella and have temporary protoplasmic outgrowths called pseudopodia. These pseudopodia or false feet help in movement and capturing prey. They include free living forms such as Amoeba or parasitic forms such as Entamoeba.
(2) Flagellated protozoa or zooflagellates
They are free living, non-photosynthetic flagellates without a cell wall. They possess flagella for locomotion and capturing prey. They include parasitic forms such as Trypanosoma, which causes sleeping sickness in human beings.
(3) Ciliated protozoa or ciliates
They are aquatic individuals that form a large group of protozoa. Their characteristic features are the presence of numerous cilia on the entire body surface and the presence of two types of nuclei. All the cilia beat in the same direction to move the water laden food inside a cavity called gullet. They include organisms such as Paramoecium, Vorticella,etc.
(4) Sporozoans
They include disease causing endoparasites and other pathogens. They are uninucleate and their body is covered by a pellicle. They do not possess cilia or flagella. They include the malaria causing parasite Plasmodium.
