General Characteristics of phylum Protozoa
- Kingdom: Protista.
- They are known as acellular or non-cellular organism. A protozoan body consists of only mass of protoplasm, so they are called acellular or non-cellular animals.
- Habitat: mostly aquatic, either free living or parasitic or commensal
- Grade of organization: protoplasmic grade of organization. Single cell performs all the vital activities thus the single cell acts like a whole body.
- Body of protozoa is either naked or covered by a pellicle.
- Locomotion: Locomotory organ are pseudopodia (false foot) or cilia or absent.
- Nutrition: Nutrition are holophytic (like plant) or holozoic (like animal) or saprophytic or parasitic.
- Digestion: digestion is intracellular, occurs in food vacuoles.
- Respiration: through the body surface.
- Osmoregulation: Contractile vacuoles helps in osmoregulation.
- Reproduction:
- Asexually reproduction is through binary fission or budding.
- Sexual reproduction is by syngamy conjugation.
Classification of Protozoa:
- Phylum protozoa is classified into four classes on the basis of locomotary organs
Class 1 Rhizopoda
- Locomotary organ:
- Mostly free living, some are parasitic
- Reproduction: asexually by binary fission and sexually by syngamy.
- No conjugation.
- Examples: Amoeba, Entamoeba
Class 2 Mastigophora/ Flagellata
- Locomotory organ: Flagella
- Free living or parasite.
- Body covered with cellulose, chitin or silica.
- Reproduction: A sexual reproduction by longitudinal fission.
- No conjugation.
- Examples: Giardia, Euglena, Trypanosoma
Class 3 Sporozoa
- Locomotory organ: Absent
- Exclusively endoparasites
- Contractile vacuoles is absent
- Body covered with pellicle.
- Reproduction: Asexual reproduction by fission and Sexual reproduction by spores
- Examples: Plasmodium, Monocystis
Class 4 Ciliata
- locomotary organ: Cillia
- Body covered by pellicle.
- Reproduction: Asexual reproduction by binary fission. Sexual reproduction by conjugation.
- Nuclei two types i.e. macronucleus and micronucleus.
- Examples: Paramecium, Voricella, Blantidium