Protista
Eukaryotic and unicellular organism are included in the protista Kingdom.
Protista have different type of Nutrition method.
1. Holophytic /photosynthetic -
They forms their food own through photosynthesis.
2. Holozoic -
They firstly intake food and then digest it.
3. Absorptive -
They firstly digest food and then absorb the digested food.
4. Mixotropic -
These protists have nutrition method more than one.
Reproduction in protista -
1. Asexual reproduction -
It is most common reproduction in protista which occurs in favourable conditions.
Asexual reproduction in protists occurs through binary fission and spore formation.
2. Sexual reproduction -
In it, two haploid gametes fused with each other and forms diploid cells zygote.
It is called is syngamy.
Life cycle of protista -
Two type of life cycle
1. Haplontic life cycle / zygotic meiosis
2. Diplontic life cycle gametic meiosis
Note- in haplontic life cycle of protist only zygote stage is deploid which on deplontic life cycle, all stages are diploid except gamete.
Many living organism are included in protista Kingdom.
A. Dinoflagellates
B. Euglenoids
C. Diatoms
D. Slime molds
E. Protozoans
A. Dinoflagellates -
These are found in marine water and they are photosynthetic in nature.
It's cell wall have hard septum surrounding that is made up of cellulose.
Most of dinoflagellates have two flagella out of which one is at right angle and another is a transversaly present in the cavity of wall septum.
Some red dinoflagellates are also present in sea water so the colour of sea becomes red because it gives red waves.
If many dinoflagellates present in a c then they are very toxic for other organism of c example, gonialax.
B. Diatoms / chrysophytes -
Golden algae and many diatoms are included in this group.
These are present in fresh or marine water.
These are very micro in size and floors with springs of water.
Cell wall of the diatoms made up of silica and form a hard skeleton around it.
This hard surrounding cannot be destroyed easily.
Diatoms lives many this type of surrounding of cell wall as the fossils.
These fossils are useful for polishing and purification of oils and syrups.
Chrysophytes are main producer in the sea.
C. Euglenoids -
Most of euglenoids are freshwater organisms found in stangant water.
Cell wall is absent on the body surface but a protein rich layer called pellicle is present which makes their body flexible.
They have two flagella one is long and other is short.
When sunlight is present they do photosynthesis but in the absence of sunlight they behave like a heterotrophs by pretdating on other smaller organism.
The pigments of euglenoids are identical to the higher plants pigment for photosynthesis example, euglena.
D. Slime molds -
These are saprophytic protists( depend on dead organic matter).
The body moves along decaying twigs and leaves engulfing organic material.
Under suitable conditions that forms a group called plasmodium which may grow and grow over several feet.
Under unfavourable conditions the plasmodium differentiates and forms fruiting bodies bearing spores at their tips.
The spores posses true walls.
They are extremely resistant and survive for many years even under adverse conditions.
The sports are displaced by the air currents.
E. Protozoans -
All protozoans are heterotrophs and leave as a predators or parasites.
They are believed to be primitive relatives of animals.
They are divided into four main groups -
1. Amoeboid protozoans -
These organs mein live freshwater sea water or moist soil.
They move and capture their prey by using pseudopodia false feet as in amoeba.amoeboid protozoans which live in marine water or sea water have silica cell on their surface.
Some amoeboid protozoans levers parasite example entamoeba.
2. Flagellated protozoans -
These are may be free living or parasitic also they have flagella parasite form of flagellated protozoans causes disease such as sleeping sickness. Example, trypenosoma.
3. Ciliated protozoans -
These are aquatic actively moving organism because of a presence of thousands of cilia.
They have a cavity (gullet) which opens to the outside of cell surface.
The coordinated movement of cilia causes the water movement with food to steered into gullet. Example, paramecium.
4. Sporozoans -
It includes a diverse organised mein which have a infectious sports live stage in their life cycle.
The most pathogenic organism malarial parasite( plasmodium) which causes malaria.
Malaria is a disease which have a staggering effect, on human population.
0 Comments