CBSE Class 11-science Answered

There are four groups of protozoa:

1. Amoeboid Protozoans:

Amoeboid protozoans live in fresh or sea water or in moist soil.

They have pseudopodia to capture their prey. The body surface of marine amoeboid protozoans is covered with silica shells.

Examples: Amoeba, Entamoeba

2. Flagellated Protozoans:

Flagellated protozoans are either free-living or parasitic.

Parasitic forms cause certain diseases such as sleeping sickness.

These protozoans have flagella for locomotion.

3. Ciliated Protozoans:

These protozoans have numerous cilia on their body. Because of the cilia, they are actively moving organisms.

Cilia help in locomotion and allow food laden water to enter the organism’s body.

These organisms are aquatic.

Examples: Paramecium

4. Sporozoans:

These protozoans have an infectious spore stage in their life cycle.

They are parasites.

Example: Plasmodium (which causes malaria)