Protozoa
(Gr., protos = first; zoon = animal)
General Characteristics
- Microscopic and acellular animals
- Solitary or colonial
- Body naked or covered by pellicle and provided with internal skeleton
- Great variety of shape : oval, spherical elongated and some are flattened
- Cytoplasm : outer ectoplasm and inner endoplasm
- Locomotary organs : Pseudopodia (in Rhizopoda), Flagella ( in Flagellata), Cilia (in Ciliata), and absent in Sporozoa
- Nutrition : Holophytic (plant-like), Holozoic (animal like), Saprozoic or Parasitic
- Respiration : Diffusion by general body surface
- Excretion through general body surface
- Reproduction : Sexual (copulaion/syngamy and conjugation) , Asexual ( Fission, Budding, Plasmotomy)
- Lifecycle exhibits alternation of generation
- No physiological division of Labour
Phylum Protozoa is divided into 2 sub-phyla and 5 classes
| Sub Phylum : Plasmodroma | Sub phylum : Ciliophora | |||
| Class : Rhizopoda/Sarcodina | Class: Mastigophora/ Flagellata | Class: Sporozoa | Class : Ciliata | Class: Suctoria |
| Locomotion by Pseudopodia, Amoeboid locomotion | Locomotion by 1 or more flagella | No locomotory organelles | Locomotion by cilia present throughout the body | Adults lack cilia, cilia replaced by suctorial tentacles |
| Mostly free living but some are parasites | Mostly free living but some are parasites | Exclusively endoparasites | Free living or endoparasites | —– |
| Body naked and without definite shape | Pellicles present so with definite body shape | Pellicles present so with definite body shape | Pellicles present so with definite body shape | —— |
| Eg: Amoeba, Entamoeba, Arcella etc. | Eg: Euglena, Trypanosoma, Leishmania, Giardia etc. | Eg : Plasmodium, Monocystis, Eimeria, Babesia etc. | Eg : Paramecium, Vorticella, Balantidium, Opalina etc. | Eg: Aceneta, Ephelota etc. |
