Protista

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:

It includes:

• 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.