General characters of protista: These are diverse kinds of predominantly water dwelling unicellular organisms, phylogenetically this kingdom links the prokaryotic monera and the complex multicellular kingdoms, of plants characters are given below.
1. Protists are all mostly aquatic.
2. Protists are unicellular, cukaryotic microorganisms.
3. They have mostly organelles of cukaryotic cells.
4. Chloroplasts present in case of photosynthetic protists.
5. Locomotory organs cilia or flagella present.
6. Cell wallis present in photosynthetic protists.
7. Locomation with the help of false feet or pseudopodia or whip like flagellum or fine hair like cilia (in paramecium).
8. These may be photosynthetic or predatory or parasitic and still some forms are saprobic i.e. living on decaying matter.
9. In these animals a sexual reproduction is by binary fission. When a parent cell produces a pair of daughter cell. Some forms reproduce but multiple fission.
10. In prostits sexual reproduction by sungamy involving the fusion of two haploid cells. Meiosis is a requirement of sexual reproduction. It either follows or precedes syngamy. It is meant for maintaining chromosome number.
11. Many eotists form protective covering called cyst during unfavorable periods common example are amoeba, Euglena, paramecium, Malaria parasite, Algae usually Eukasyotic organisms.
Phylum protozoa: – All protists are included in this single phylum. Formerly this group was classified as a subkingdom of kingdom animalia.