KINGDOM PROTISTA

WHAT ARE THE PROTISTANS---

Kingdom protista iuncludes all the unicellular eukaryotic organisms.which are primarily auqatic found in both marine and fresh environments.Being eukaryotyes they contain well developed genetic material organised in a nucleous with two membranous envelop and other cell organelles like mitochondria,chloroplast, golgi body, ribosomes etc. This kingdom include  chrysophytes,dianoflagellates,euglenoids,slime moulds and protozoans.They reproduce both asexually and sexually through cell fusion and zygote formation.

CHRYSOPHYTES-

Chrysophytes include diatomes and desmids. They are microscopic oganisms,photosynthetic and planktonic that flow passively with the water currents.Desmids are also known as golden algae.In the case of diatomes,there are thin overlapping of cell wall fitted together like a coverings of a box. the cell wall of diatomes are embaded with silica that make their wall indestructable and thus after dying diatomes left a large amount of cell wall  deposition in their habitats and being deposited over billion of years it form diatomicious earth,which use in polishing and filtration of oils etc.Diatomes lack throughout their life and are the chief producer of sea.

DIANOFLAGELLATES- 

Dianoflagellates are found in marine water and are mostly photosynthetic autotrophs. Dianoflagellates are colourful protist appear yellow,green,brown,blue or red depending on main pigment present on their cell.They have thin cellulosic plate on their cell wall and have two flagella one longitudinally arrange and other lie transversely  between the cell furrow. Flagella are of heterokont type in case of dianoflagellates. Red dianoflagellates like Gonayulax form red tides in sea by rapid multiplication and toxin release by such rapid multiplication kill the marine animals like fishes etc.

EUGLENOIDS-

Euglenoids are connecting connecting link between plant and animals.They are mostly found in fresh stagnant water environments.They have protein rich layer pellicle that make their body flexible .Though they perform photosynthesis in the presence of light but in the absence of light they behaves like heterotrophs by predating the smaller organisms.Interestingly the pigments present in Euglenoids are similar to the pigments p[resents in higher plants like chlorophyll a.

SLIME MOULDS-

Slime moulds are the saprophytes,they known as saprophytic protist.They engulf dead organic matters and decaying twigs and leaves also.They are well known for forming plasmodium under feavourable condition that may spread over several feet and when the envoironment is unfeavourable this plasmodium degenerates and form fruiting body bearing spore at their tips.This spore possess true cell wall that help to survive in unfeavourable condition upto many years.Spores are disparse through air current.

PROTOZOANS-

All the protozoans are heterotrohes and the majorities are decomposer. The protozoans are the primitive relatives of animals.They can be amoeboids,cilliated,flagellated and sporozoans etc.

Amoeboid protozoa-

They are found in fresh and marine water and also in moist soil. They have false feet pseudopodia that helps in capturing the prey.The marine form have silica on their cell surface. some parasitic forms like Entamoeba histolytica cause disease.

Ciliated protozoans-

They are actively movable organisms found in aquatic environments. They possess thousands of cilia that works like oars and helps in engulfing the food at gullet, a cavity on cell surface.The most famous one is paramoecium.

Flagellated protozoans-

Flagellated protozoans are live as a predators or parasites and actively moving because of presence of flagella.Parasitic form cause disease such as sleeping sickness cause by trypanosoma a flagellated protozoa and the vector is tse-tse fly. 

Sporozoans-

sporozoans have infectuous  spore like stage in their life cycle.Plasmodium malarial parasite cause malaria disease that had a very bad  impact on human population.plasmodium has two host,pig is the secondary and human is primary host and plasmodium is digenetic type.