5 Answers
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.
Four major groups of Protozoa is as follows:
a. Amoeboid protozoans: The amoeboid protozoans live in freshwater, sea water or in moist soil. They produce pseudopodia for locomotion and for capturing food. The marine forms have silica shells on their surface. Some of them are parasites, e.g. Entamoeba histolytica.
b. Flagellated protozoans: They are either free-living or parasitic. Flagella is present for locomotion. Many of them are parasites, e.g. Trypanosoma.
c. Ciliated protozoans: They are aquatic. Cilia are present for locomotion. A cavity (gullet) is present which opens to the outside of the cell surface. The coordinated movement of cilia facilitates the entry of food-laden water into the gullet. Example: Paramoecium.
d. Sporozoans: The sporozoans have an infectious spore-like stage in their life cycle. Example: Plasmodium.
There are 4 major groups of protozoa.
(1) Amoeboid protozoans or sarcodines
They are unicellular, jelly-like protozoa found in fresh or seawater 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 for locomotion. 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 protozoans 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 and free-living forms such as Noctiluca.
(3) Ciliated protozoans 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 Paramaecium, 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.
Protozoans are heterotrophs act either as predators or parasites.
They are of four groups
1. Amoeboid protozoans: They capture their prey by using pseudopodia. They live in freshwater. Some are parasites
Eg: entamoeba.
2. Flagellated protozoans: They are free-living or parasites. They cause diseases,
Eg: Trypanosoma-sleeping sickness.
3. ciliated protozoans: They possess cilia in their body surface for locomotion. They have gullet for food intake.
Eg: Paramecium
4. Sporozoans: They are sporeproducing organism that causes diseases
Eg: plasmodium causing malaria.
Four major groups of Protozoa are as given below:
1. Amoeboid Protozoa:
They are found in freshwater, seawater or moist soil. They have pseudopodia, like amoeba, hence the name ameoboid protozoa.
2. Flagellated Protozoans:
They have flagella helps in locomotion. Some are parasite.
Eg. Trypanosoma causes sleeping sickness.
3. Ciliated Protozoa:
They have thousands of cilia present all over the body. The cilia helps in locomotion and steering of food into the gullet.
4. Sporozoans:
Many protozoans have an infectious spore like stage in the life cycle. The spore-like stage helps them get transferred from one host to another host.