Kingdom Protista | Characteristics, Classification, Examples

Hello friends, do you want to know about Kingdom Protista, if yes then you have come to the right post. Today we tell you what is the Kingdom Protista. If we will tell about it step by step, then let’s start.

What is Kingdom Protista?

In this kingdom, single-celled organisms with eukaryotic cells have been placed. The cell wall is present in only a few of them. It contains a nuclear membrane. Their mode of nutrition is mixed, which means they have both autotrophs and heterotrophs. The method of reproduction in these is gamete-conjugation and conjugation.

Characteristics of Protista –

• Eukaryote organisms are kept in this Kingdom. This means in eukaryotic cells are found. And those cells in which a concentrated nucleus or nuclear envelope is found are called eukaryotic cells .
• Single-celled organisms are kept in this Kingdom.
• Most of the creatures in this kingdom are aquatic and in this type of water, and they are found in salty water.
• The organisms of the Protista kingdom are both autotrophic and heterotrophic. Not only this, but it also contains mixed nutrients. Mixed nutrients mean when there is both autotrophic and heterotrophic nutrition inside the same organism, then they are called mixed nutrients.
• Example – Euglena It has both types of nutrition.

Classification of Kingdom Protista –

The Kingdom Protista is divided into three parts on the basis of nutrition.

1. Autotrophic/Photosynthetic Protist
2. Consumer protists
3. Consumer (Parasitic) protist

Autotrophic/Photosynthetic –

Organisms that make their own food and are not dependent on other organisms are called autotrophs. They are placed in three types of groups.

1. Chrysophyte
2. Dinoflagellate
3. Euglenoid

Consumer (Symbiotic) –

The organisms which depend on others for their nutrition or food, then such organisms are called consumers. Meaning of saprophytes The organisms which get nutrition from rotten or dead substances are called saprophytes. There are bacteria and fungi, similarly, there is an organism in the Kingdom Protista which is called slime mould. So the downy mildew is kept in this group.

Consumer (Parasite) –

Protozoa have been kept in this group, and parasite means such organisms which depend on other organisms for nutrition and accommodation are called Parasites.

Examples – Lice, Ticks, etc.

Chrysophyte –

• Two types of creatures have been kept inside it. Diatoms and Desmid (Golden Algae), In this, we will mainly study Diatoms.
• They are found in fresh water and marine water mostly found in marine water.
• These are Phytoplankton, which means they are autotrophic and float on the surface of the water.
• Chrysophytes make the maximum food on this earth and in this chrysophytes also make maximum diatoms, hence they are also called main producers because they are doing maximum photosynthesis on this earth.

What are diatoms?

1. Their cell wall becomes hard by absorbing silica present in water. This rigid cell wall is called a frustule. This frustule is made of two parts. The first upper part is called epitheca and the second lower part is called hypotheca.
2. Why are they called diatoms, see the meaning of Di is two and here the meaning of atom is covering, now these two coverings are made up of epitheca and hypotheca, hence they are called diatoms and their structure is like a soap dish.
3. When these Diatoms are dead, they get collected at the base of the sea because they were not affected by any acid, high temperature, or light because their cell wall was very hard. Now, this gathering structure is called Diatomy Soil or Diatomite.

Use of diatomic soil –

1. It is used in making paint.
2. Used in making toothpaste.
3. Used in making wood polish.
4. Used in making oil.
5. It is used in making walls of furnaces because they are not affected by high temperatures.
6. These diatoms act as pollution indicators. Pollutant indicator means that water which has pollutant elements in it, then these diatoms will not grow there.

What is polluted water?

The water in which the amount of dissolved oxygen is less is called polluted water. Now in the water where the amount of oxygen is low, organisms will not be able to survive, and if diatoms are put in such water, they will also not be able to survive, then we get information from them that this water is polluted, hence they are called pollutant indicators.

Examples – Triceratum, Navicula, Cymbella, etc.

Now, friends, we will read about Dinoflagellates.

What are dinoflagellates?

1. These are green, yellow, red, brown, and blue in all these colors, that is, they will be of the same color as the pigment inside them. If there is a red pigment then it will be red, if it is yellow then it will be yellow.
2. These are mostly found in saline water or the sea.
3. Their cell wall is made of cellulose and pectin due to which the cell wall becomes very rigid. This hard cell wall is called Lorica, it works as a shield or weapon.
4. They are bicellular structure means two flagella are found in them which is why they are called Dinoflagellates Dino means two and Flagellate means flagellum.
5. In these, one flagellum is perpendicular to the body which is called the sulcus and one is found transverse to the body which is called the annulus.

Note1 – Some dinoflagellates show bioluminescence means they make light in the dark of night. E.g. Noctileuca, Pyrodinium.

2 – Due to some Dinoflagellates, red waves come from the sea, which is called Red Tide. Like – Gonialax, Gymnodinium, etc.

Now, friends, we will read about Euglenoid, so let’s know it too.

What are euglenoids?

1. They are mostly found in clear water.
2. The cell wall is not found in these but in its place, a flexible, protein-rich membrane is found which is called Pellicle.
3. There is an involution in their front, that is, it is folded inwards. Two flagella emerge from inside this involution, one is long and the other is short. Euglena moves rapidly with this long flagella.
4. A structure is found near the base from where the flagellum emerges, which is called the photosensitive eye spot or Stigma, its function is to move the euglena towards the light.
5. A contractile vacuole is found inside them, whose work is to control the amount of water, that is, if the amount of water inside them increases, then it expels the water and if it decreases, then the water is released. accumulates.
6. Euglena contains photosynthetic pigments such as chlorophyll-a, chlorophyll-b, and xanthophyll, and these pigments are found in higher plants.
7. They store their food in the form of paramylon starch after photosynthesis.
8. Its nutrition is mixed, which means it makes its food by photosynthesis during the day, while it eats Diatom/Dinoflagellates the night, which means it is both autotrophic and heterotrophic, and in which both these types of nutrition are available, they are called mixed nutrition.

What are Slime Moulds?

1. These are saprophytes.
2. It is mostly found in yellow color.
3. They are single-celled.
4. The cell wall is not found in them.
5. They contain naked protoplasm. Which is multicentric, and its name is Plasmodium.
6. Under favorable conditions, these Slime moulds come close to each other and form a colony. Favorable conditions mean they are getting enough food and water.
7. In unfavorable conditions, these Slime moulds live far away from each other. And in this condition, they shrink their protoplasm and form a structure called a fruiting body. And all cell organelles are present in this protoplasm.
8. I have already told you that there are many nuclei in these, now around each of these nuclei the endoplasmic reticulum and Golgi body together form the cell membrane. After that, they form another covering over the cell membrane which is called the cell wall.
9. Now each nucleus has changed into a new structure and this structure is called Spore. We can also call this spore a new cell. Now a lot of spores will be formed inside the fruit body, due to which the membrane of the fruit body will burst and all the spores will come out.
10. Now in what condition are these spores that have come out, in unfavorable conditions, now will these spores die in this condition, will they not die, because these spores are surrounded by a strong cell wall that protects them and as soon as this favorable condition When they come in, their cell wall breaks down and they start nourishing.
11. After that, there is a division of the nucleus in their cytoplasm, due to which many nuclei are formed in them, as a result of which they become multinucleated. That is, they turn into Plasmodium like before.

What are protozoa?

Protozoa were first discovered by scientist Anton van Leeuwenhoek.

These are parasites or can be predators. Predators are those organisms that eat or get nutrition by killing other organisms. are called predators.

Classification of Protozoa –

Protozoa are classified on the basis of locomotor organs. This means the part by which the living beings move.

Protozoa are divided into four parts.

1. Amoeboid protozoans
2. flagellated protozoans
3. Ciliated protozoans
4. Sporozoans

Amoeboid protozoans –

• As you must have come to know from the name which creature has been kept in it. Amoeba is placed.
• The organ which helps in walking in this is called pseudopodia. False feet, means whose shape keeps changing, and what is called feet – The structure that comes out of the body is called feet.
• Like our hands and feet, in the language of science, they are called forefeet and hind feet. Now the shape of our hands and feet does not change, but when amoeba has to move, the shape of the fart that comes out of them keeps on changing, that is why their locomotion organ is called pseudopod.
• Their locomotor organs help not only in walking but also in catching food.
• Amoeba is found in both fresh and marine water. They are also found in wet soil.
• Examples – Amoeba proteus and Entamoeba histolytica. Amoeba proteus is found in seawater and Entamoeba histolytica is found in freshwater, and this causes amoebic dysentery in humans.

Flagellated protozoans –

• In the organisms of this group, the movement organ is the flagellum.
• Most of the organisms in this group cause diseases.
• Example – Trypanosoma gambiense. This is a parasite found in the saliva of the Tsetse fly. Its scientific name is Phlebotomus argentipes and when this fly bites a person, Trypanosoma gambiense goes inside that person and causes a disease called sleeping sickness.
• In this disease, the person is not able to sleep properly. There is restlessness, there is no time left to sleep, and his entire sleeping time gets spoiled.

Ciliated Protozoa –

• It has locomotor organs (cilia). Along with making the movement of the organism, these cilia also make the substances present in the environment like food, etc.
• Example – Paramecium codetum, which feeds on phytoplankton and zooplankton. That means it is a predator.
• It is binucleated. There is a small nucleus called the short nucleus which undergoes mitosis and a large nucleus called the long nucleus. It does asymmetric division.

Sporozoans –

• They do not have locomotor organs.
• They travel through carriers. The carrier can be water, air, or even an animal. For example, Plasmodium organisms are transmitted by female Anopheles mosquitoes.
• Most Sporozoa are parasitic.
• Example – Plasmodium, was discovered by Levrane and it causes malaria which is transmitted through the bite of a female Anopheles mosquito. And it was reported by Sir Ronald Ross that Plasmodium is present in the saliva of female anopheles.

There are mainly four species of Plasmodium.

1. Plasmodium vivex
2. Plasmodium falciparum
3. Plasmodium malariae
4. Plasmodium ovale

Some important questions and answers.

Q.1 Which organisms come in Protista?

Ans. Eukaryotic cells are single-celled organisms.

Q.2 Where do protists usually live?

Ans. Lives in water.

Q.3 The link between the two animal groups of Protista is?

Ans. Euglena

Q.4 Into how many parts is the Protista kingdom divided?

Ans. The Kingdom Protista is divided into three parts on the basis of nutrition.

1. Autotrophic/photosynthetic protist
2. Consumer protists
3. Consumer (parasitic) protist

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