3.BIOLOGICAL CLASSIFICATION

II.KINGDOM PROTISTA 

 All are unicellular and eukaryotic. 

 Mostly aquatic, can live in moist places. 

 Forms a connecting link between plants, animals and fungi.

 Kingdom Protista includes Chrysophytes, Dinoflagellates, Eugleoids, slime mould and Protozoans.

1. CHRYSOPHYTES 

o They includes diatoms and golden algae (desmids) ,found in fresh water as well as marine water.

o In diatoms cell wall forms two thin overlapping plates which fit together as in soap box.

o The deposition of silica embedded cell walls of diatoms in ocean bottom is known as diatomaceous earth.

o The soil of diatomaceous earth is gritty and it is used in polishing, filtrations of oils and syrups.

o They are chief producer in oceans.

2.DINOFLAGELLATES

o They are basically unicellular, motile, biflagellate and photosynthetic protists.

o Predominant colour is golden brown but yellow, green, red and even blue also exists.

o Some Dinoflagellates like Gymnodinium and Gonyaulax grow in large number in the sea and make the water 

look red and cause the so called “red tide”.

 3. EUGLENOIDES 

o They are Euglena like unicellular flagellates which possess pellicle instead of cell wall which make their 

body flexible.

o They have two flagella, one short and other long.

o They are photosynthetic in presence of sunlight and act as predators in absence of sunlight.

o Example- Euglena, Peranema.

4.SLIME MOULDS 

o They are saprophytic protists and feeds on decaying twigs and leaves.

o Under favorable condition, they form an aggregation called plasmodium which produce fruiting bodies 

bearing spores.

o The spores are extremely resistant and survive for many years.

o Example- Physarum, Fuligo.

5.PROTOZOANS 

o All protozoans are heterotrophs and live as predators or parasites.

o They are considered as primitive relatives of animals.

o There are four major groups of Protozoans

a).AMOEBOID PROTOZOANS 

 Move and Catch prey using pseudopodia, e.g., Amoeba. 

 Many forms have silica shells on their surface. 

 Some of them are parasitic e.g. Entamoeba

b).FLAGELLATED PROTOZOANS 

 Either free living or parasitic. 

 They have flagella. 

 Cause disease like sleeping sickness e.g., Trypanosoma

c).CILIATED PROTOZOANS 

 These are aquatic, actively moving organisms due to presence of thousands of cilia. e.g., Paramecium. 

 They have a cavity called gullet that opens to outside the cell.

 Eg. Paramecium, Vorticella

d).SPOROZOANS 

 Lack any locomotary organelle. 

 All members are parasitic. 

 Have infective spore like stage in life cycle, e.g., Plasmodium which causes Malaria.