Kingdom protista includes unicellular, eukaryotic and microscopic organisms. They are primitive eukaryotes.
Types of protista:
- Plant-like protista (producer)
- Animal like protista (consumer)
- Fungus like protista (decomposer)
Plant like Protista:
- Euglena like organisms having mixotrophic mode of nutrition→ Euglenophyta
- Diatoms ( Bivalvea, unicellular, photosynthetic algae)→ Chrysophyta
- Dinoflagellates (Biflagellate, unicellular, photosynthetic algae)→Pyrrophyta
Animal like Protista:
It includes protozoans→ Protozoa
Fungus like Protista:
It includes slime moulds ( unicellular, saprobic, fungus like)→ Gymnomycota
Characteristics of Protista:
- They are unicellular, eukaryotic and microscopic.
- They may be photosynthetic, holozoic, saprobic, parasitic.
- Mostly they are aquatic and some are found in damp soil.
- Locomotory organelles may be present or absent if present they may be pseudopodia, cilia, flagella.
- The cell of some Protista contains the cell wall and others do not have the cell wall.
- Digestion is intracellular.
- It occupies all the 3 niche of ecosystem i.e. they may be the producer, consumer or decomposer.
- They are the connecting link between prokaryotes and higher eukaryotes.
- Reproduction is carried out by both sexual and asexual method.