Question

Provide a protozoan classification.

Answer 1

Protozoa:

1. Protozoa are single-celled creatures.
2. They range in size and shape from amoeba, which can change shape, to paramecium, which has a fixed shape and a sophisticated structure.
3. Eukaryotic and single-celled creatures make up the majority of protozoans.
4. Amoeba, Paramecium, Trypanosoma, Plasmodium, and other protozoa are examples.

Classification:

1. The protozoa are currently divided into six phyla based on light and electron microscopic characteristics.
2. The phylum contains the majority of the species that cause human disease, like Apicomplexa and Sacromastigophora.
3. Flagellates, Ciliates, Sarcodina, and Sporozoans are the four primary categories they belong to.

A. Mastigophora or Flagellated protozoans:

1. They are parasitic or free-living.
2. They have flagella for movement/locomotion.
3. Their body is covered with pellicle or cuticle.
4. Freshwater forms have a contractile vacuole.
5. Reproduction occurs by binary fission (longitudinal division).
6. Examples include Trypanosoma, Trichomonas, Giardia, Leishmania, etc.

B. Sarcodina or Amoeboids:

1. They live in freshwater, sea, or moist soil.
2. The movement takes place by pseudopodia.
3. They capture their prey with the help of pseudopodia.
4. There is no definite shape.
5. The pellicle is absent.
6. Contractile vacuoles are present in freshwater amoeboids.
7. Reproduction occurs by binary fission and cyst formation.
8. Examples include Amoeba, Entamoeba, etc.

C. Sporozoa or Sporozoans:

1. They are endoparasitic.
2. They do not have any specialized organs for movement/locomotion.
3. The pellicle is present, which contains subpellicular microtubules, which help in movement.
4. Reproduction occurs by sporozoite formation.
5. Examples include Plasmodium, Myxidium, Nosema, Globidium, etc.

D. Ciliophora or Ciliated Protozoa:

1. They are aquatic and move actively with the help of thousands of cilia.
2. Due to the covering of the pellicle, its shape is fixed.
3. They may have tentacles, e.g. Subclass Suctoria.
4. Contractile vacuoles are present.
5. Some species have an organ for defense called the trichocyst.
6. They move with the help of cilia and the cilia's movement also helps carry the food inside the gullet.
7. They reproduce by transverse division and also form cysts.
8. Examples include Paramecium, Vorticella, Balantidium, etc.