Protists;Characteristics, Types and Complete Explanation

Protists that are similar to these animals have certain characteristics. The characteristics possessed by protists resemble animals or protozoa are as follows. First, protozoa are single-celled animals or known as unicellular.

Second, the cell size of the protozoa is between 3 – 1000 µm. Third, cells from these protozoa have a nucleus or eukaryotic membrane. Fourth, protozoa do not have cell walls. Fifth, protozoa live in wet or watery habitats.

Sixth, asexual reproduction of protozoa by splitting or binary fission. Seventh, in an unfavorable environment, protozoa will defend themselves by forming cysts.

Eighth, protozoa have artificial limbs in the form of pseupodia legs , whip hair or flagella , or hair shakes or cilia .

After understanding about the characteristics possessed by protozoa, it turns out protozoa have various types. The next discussion will explain the types of protozoa.

Types of Protozoa

The types of protozoa are distinguished by their motors, which produce four classes. The four classes are Rhizopoda or Sarcodina , Flagelata or Mastigophora , Ciliata or Ciliophora , and Sporozoa or Apikomplexa .

The explanation of each of the protozoa classes can be explained as follows.

First, the Rhizopoda or Sarcodina Class . Rhizopoda comes from the words rhizo and podos. Rhizo which means root. Podos which means feet. Rhizopoda or Sarcodina (sarcodes which means meat). This class has the following characteristics:

  • Asexual reproduction by dividing themselves.
  • Habitat can be found in waters that contain lots of organic substances.
  • Having an irregular body shape, consisting of ectoplasm and endoplasm.
  • Is a single-celled animal or known as unicellular.
  • The locomotor is a cytoplasmic protrusion called pseupodiaor pseudo feet.

Besides having the characteristics – the above that distinguishes it from other classes. Rhizopoda has a body structure, which consists of: contractile vacuoles, nucleus, food vacuole, pseupodia, uroid, mitochondria, endoplasma, and ectoplasm which consists of layers of hyaline and plasmagel.

This nucleus or cell nucleus has the function to regulate all activities that occur within the cell. This contractile vacuole or pulsed cavity has a function for the excretion organs of leftovers.

In addition, this contractile vacuole also serves to keep the cell osmosis pressure always higher than the surrounding osmotic pressure. This food vacuole or food cavity has a function for digestion.

The example of Rhizopoda is as follows:

Amoeba, some live in the human body and some live in a free environment. Examples are Entamoeba histolitica , Entamoeba dysentriae which can cause dysentery, and Entamoeba coli which can help in the process of decaying metabolic waste.

Amoeba’s body structure consists of cell membranes, ectoplasms, endoplasms, and cell organelles. Each can be explained as follows.

  • Cell membrane is a protective part. In addition, it is a gateway for entry or exit of substances.
  • Ectoplasm is a clear cytoplasm and is located near cell membranes.
  • Endoplasm is a cytoplasm located inside the ectoplasm. Endoplasm is thicker when compared to ectoplasm. In addition, it also appears turbid because of the granules or granules. This endoplasm together with ectoplasm plays a role in the movement of amoeba. Changes in water content on one side of the body of amoeba can cause cytoplasmic flow and the formation of pseudopodia. This amoeba with pseudopodia is called the amebid motion.
  • Cell organelles are tools within the endoplasm. Examples include cell nuclei, food vacuoles used to digest food, and contractile vacuoles used to regulate water content in the cytoplasm or osmoregulator and as a tool for excretion of residual substances in liquid form.

Amoeba food is generally in the form of algae, bacteria, other protozoa, and dead plants. Food is taken by catching or phagocytosis.

Amoeba put food in the food vacuole and digested it through artificial foot movements.

Meanwhile, amoeba breathing. Gas exchange occurs through the entire surface of the body. Oxygen then diffuses from water through the cell membrane. Then, enter the cell.

Oxygen is used to oxidize food so that it can produce energy and carbon dioxide as a waste. Furthermore, carbon dioxide is released through the cell membrane.

Radiolaria, this has a habitat in the sea. This fossil from Radiolaria is composed of silicates which form radiolaria soil which can be used as material for scouring.

Foraminifera has a habitat in the sea. Fossils from Foraminifera can form globigene soil that can be used as a reference for petroleum sources.

Second, the Class Flagellata or Mastigophora . Flagellate comes from the word flagellum. This flagellum means whip hair. Flagellata or Mastigophora has a meaning that is mastix which means whip hair while phoros which means to carry.

The characteristics of the flagellate class are as follows.

  • Flagellate body size is between 35 – 60 µm.
  • Flagellates are single-celled or unicellular animals.
  • Flagellates have a fixed cell shape and do not have a frame.
  • In general, flagellates have chloroplasts.
  • The flagellate motion tool is a flagellum.
  • Most flagellate places live in fresh water.
  • Flagellates have autotrophic properties and eat organic substances in the form of a solution.
  • This reproduction of flagellates asexually by splitting lengthwise or vertically.

So are some of the features of the flagellate class that distinguishes from other classes. Next, it is explained about the body structure possessed by flagellates, as follows.

The body structure possessed by flagellates consists of flagella, stigma, nucleoli, nucleus, chloroplasts, contractile vacuoles, and pelicles. This contractile vacuole is a place that is used for disposal of residual substances.

Chloroplast is the place of photosynthesis. The nucleus is the nucleus of the cell. Pellicles are the outermost layers formed from proteins.

The example of flagellates is as follows.

Trichonympha and Myxotricha which can live in termite intestines. In addition, it helps termites digest wood. This is due to Trichonympha and Myxotricha having cellulose enzymes.

Euglena viridis , Volvox , and Pandorina who have chloroplasts. This has a role as a producer in aquatic ecosystems. Trichomonas vaginalis which can cause inflammation in the human vagina or known as vaginitis .

Noctiluca miliaris that can live at sea. In addition, it can cause the sea to look radiant at night.

Trypanosoma gambiense can live in the salivary glands of Tsetse or Glossina palpalis which can cause “sleep” disease.

Third, the class Ciliata or Ciliophora. Ciliata is derived from the word cilia or cilia which means feather shakes. Thus, ciliates are protozoa which have vibrating hairs that can be used for their movements.

Meanwhile, cilia as excitatory devices. In addition, cilia also function as food makers. The characteristics of ciliata or ciliophora are as follows.

  • Ciliates are single-celled animals that have a fixed body shape.
  • Ciliates have two cell nuclei. The cell nucleus, the macronucleus,is an asexual reproduction tool and the micronucleus is a sexual reproduction tool.
  • Ciliate has a cleft in the mouth and is equipped with anus cells.
  • On the ciliate cell wall there are hair shakes or cilia. This cilia are used as a means of movement.
  • Ciliate reproduction is done sexually by conjugation. Then, reproduce asexually by dividing yourself.
  • Ciliates live in fresh waters where they contain a lot of organic substances.

Thus the characteristics of ciliates that distinguish with other classes, then what about the structure of the ciliate body. The body structure possessed by ciliate, which is as follows.

The example of protists is as follows. First, the stentor has the shape of a trumpet with a device attached to the substrate.

Second, Paramecium caudatum , which performs asexual reproduction by dividing itself or transverse direction. Then, sexually by way of conjugation.

Third, Balantidium coli , which lives in the human colon. In addition, it can cause balantidiosis or balantidium dysentery.

Fourth, Sporozoa Class or Apikomplexa. Sporozoa consist of two words namely spore and zoon. Spores are interpreted as seeds and zoon are interpreted as animals.

Sporozoa are a group of protizoa that do not have a means of movement, either in the form of cilia, flagella or pseudopodia. The movement of the Sporozoa is done by changing the position of his body. Sporozoa’s body is elliptical or oval shaped.

Sporozoa are generally parasitic which can cause disease in humans and animals. Respiration and excretion from Sporozoa is done by diffusion. Food is obtained by absorbing nutrients from the host.

This class has certain characteristics that can distinguish it from the previous three classes. The characteristics of the Sporozoa class are as follows.

First, Sporozoa can form a kind of spore in their life cycle. Second, Sporozoa are single-celled animals. Third, Sporozoa do not have a means of movement.

Fourth, Sporozoa reproduction is done asexually by schizogoni or splitting into the body of the host. In addition, sporogony or spores form in the body of the host.

Furthermore, sexual reproduction can be done by melting gametes inside the body of a mosquito or its host.

The example of sporozoa is Plasmodium. Plasmodium can live in its host cell, which is a mosquito. Plasmodium has several types, as for the types of Plasmodium and their roles are as follows.

  • Plasmodium ovale which can cause malaria oviana tertiana or spleen.
  • Plasmodium malariae which can cause quartane malaria with sporulation period every 1-3 x 24 hours.
  • Plasmodium vivax which can cause malaria tertiana, with a period of sporulation or fever symptoms every 2 x 24 hours.
  • Plasmodium falcifarum which can cause tropical malaria with sporulation period every 1-3 x 24 hours.

The method of reproduction and life cycle of Plasmodium was discovered by Grassi and Ronald Ross. The vector derived from Plasmodium that causes malaria is female Anopheles mosquito.

Plasmodium lives by means of parasites on human red blood cells or other vertebrates. During his life, Plasmodium underwent two phases namely the sporogoni phase and the schizogony phase.

The sporogonic phase can occur in the body of female Anopheles mosquitoes. Meanwhile, this phase of schizogony occurs in the human body. Sporozites or malaria parasites enter the human body through mosquito bites.

Sporozites enter the liver cells and then experience multiple growths and divisions by forming cryptozoid or so-called eksoeritrositer phase. For about three days, sporozite leaves the liver cells into red blood cells.

Then, it turns into tropozite or called erythrocyte phase. Furthermore, this tropozite nucleus undergoes multiple division. Then each core is wrapped by cytoplasm to form merozoites or called the schizogony phase.

When red blood cells break down, some of the merozoites attack other red blood cells and some of them turn into gametocytes. When mosquitoes suck blood containing merozoites, gametocytes will enter the mosquito’s body together with blood cells.

Gametocytes will turn into male gametes or called microgamocytes and female gametes or macrogametocytes. If fertilization occurs, a zygote will form. Inside the mosquito’s stomach wall, then the zygote turns into an ookinet.

Then, ookinet through the stomach wall. Then, stick to the outside. In the stomach wall, the ookinet then turns into an oocyst. The oocyst nucleus divides into sporozoites.

Then, the sporozoites move towards the salivary glands. And ready to enter the human body through its bite. The following is an illustration of the Plasmodium life cycle.

The Role of Protozoa in Life. Some protozoa have good benefits for life. However, several other protozoa are also responsible for various diseases caused.

The benefits of protozoa are as follows.

  • Assist the process of spoilage of food scraps. The life of protozoa in the human body can be used to help the process of spoilage of food debris. Examples of protozoa that help the process of food spoilage are Entamoeba coli which can live in the large intestine.
  • As a basic material for making scouring tools. Radiolaria shell deposition at the bottom of the water will form radiolaria soil. Where the soil contains grit and can be used for abrasive.
  • As an indicator for petroleum. Globigerina body skeletal deposits at the bottom of the waters will form globigerina soil. These deposits are generally used to indicate the presence of petroleum.

Furthermore, besides having benefits, Protozoa also has life-threatening effects because it can be a disease for humans and animals. The impact of protozoa is as follows.

  • Plasmodium sp which can cause malaria. The intermediate host is the female Anopheles mosquito.
  • Leismania donovani which can cause illness when – azar in humans. This disease is characterized by symptoms and a swollen heart, and a prolonged fever. The intermediate host is the Pholobotomus mosquito.
  • Trichomonas vaginalis which can cause itching in the vagina and vaginal discharge.
  • Trypanosoma gambiense and Trypanosoma rhodesiense which can cause sleeping sickness in humans. The intermediate host is the tsetse fly (Glossina palpalis and Glossina morsitans).
  • Trypanosoma cruzi which can cause chagas in children.
  • Entamoeba histolitica lives in the human small intestine and can cause dysentery.
  • Gingivalis entamoeba that lives in the oral cavity and can cause gingivitis.
  • Balantidium coli that live in thick intestine or human colon which can cause diarrheal disease (balantidiosis).
  • Trypanosoma evansi which can cause sura disease in livestock. The intermediate host is the Tabanus fly.

After understanding about animal-like protists. The next discussion will explain about Protists that are similar to plants or Algae.

Also read:  Fungus or Mushroom: Characteristics, Structure, Way of Life, Reproduction, and Classification

Plant-like Protists or Algae

Protists that are similar to plants have certain characteristics to be easily recognized. The characteristics possessed by Protista are similar to plants or algae, which are as follows.

First, plant-like protists are unicellular and multicellular. Second, plant-like protists have cell walls composed of cellulose. Third, plant-like protist cells have a core or eukaryotic membrane.

Fourth, the body structure of Protista resembles plants such as the thallus plant. This is due to not having true roots, stems and leaves.

Fifth, plant-like protists have color pigments, including chlorophyll, xanthophyll or yellow, carotene or golden color, phicoeritrin or red, phycocyanin or blue, and others.

Sixth, plant-like protists can carry out photosynthesis so they can be said to have photoautotrophic properties. Seventh, plant-like Protista habitat is in waters and in humid places.

Eighth, asexual reproduction of plant-like protists is done by splitting themselves up in unicellular algae. Then, forming this fragmentation is carried out by multicellular algae.

Besides having the characteristics above, plant-like protists or algae have various types. The next discussion will explain the types of Algae.

The types of Algae are classified based on the color of the pigment. Algae are classified into five groups, namely Green Algae, Red Algae, Golden Algae, Fire Algae, and Chocolate Algae. The explanation of these groups is as follows.

Green algae or Chlorophyta . This alga contains the main pigment that is chlorophyll or green. In addition, it has additional pigment in the form of carotene. Green algae live in waters, both fresh and seawater.

Furthermore, these green algae symbiotic with fungi form lichen. Green algae have a diverse body structure. There are unicellular ways of living solitary or colonized and multicellular.

Green algae become important. That is because the ancestors of green algae are believed to be the origin of all plants on land. This is supported by the hypothesis, as follows.

First, green algae have chlorophyll a and b. Second, green algae have cellulose cell walls. Third, green algae can store food in the form of starch or starch.

Reproduction carried out by green Algae is sexually and asexually. Asexual reproduction is done by splitting, fragmentation, and spores.

Then, sexual reproduction is carried out by means of isogamy, anisogamy, and oogamy. The examples of green algae are Protococcus, Chlorella, Chlamydomonas, Spirogyra or filamentous, and Ulva lactua or talus-shaped.

Brown Algae or Phaeophyta . This algae has the main pigment content which is fikosantin or chocolate pigment. Reproduction carried out by brown algae is sexually and asexually.

Asexual reproduction is done by fragmentation, zoospores. Meanwhile, sexual reproduction is done by oogamy, eggs produced by oogonia, and sperm produced by antheridia.

On the cell wall of brown algae, in addition to cellulose there are also alginic acid. Then, there are accessory photosynthetic pigments or additions of chlorophyll a and c, xanthophyll, carbon-carbohydrate deposits.

The example of chocolate Algae is Laminaria sp. which can produce alginic acid needed for the production of textiles, food, and cosmetics, Sargassum, Fucus, Turbinaria decurens, and Macrocystis.

Red algae or Rhodophyta . Red algae contain the main pigment, namely fikoeritrin or red pigment. Where almost all types of rhodophyta live in the sea. Members of this red algae group can be found in coastal areas with depths of up to 100 meters.

These multicellular red algae are mostly in the form of simple sheets with delicate branches resembling ribbons. Inside the cell there are red pigments and blue pigments. Where through the two pigments, light waves that enter the sea are absorbed.

Then, transferring light energy to chlorophyll for photosynthesis purposes. The form of the results of the photosynthesis process is similar to the glycogen commonly called fluoridean flour.

Some types of red algae can be used for food, for example made in order. In Indonesia, the material for making agar comes from Eucheuma spinosum. Meanwhile, in countries that have cold climates in general use Gelidium and Gracilaria.

In aquatic ecosystems, the presence of red algae is able to contribute to the formation of coral reefs. This is possible because some types of red algae can store calcium carbonate in body tissues.

Red Algae reproduction can be done by asexual and sexual means. Asexual reproduction is done by means of spores. Then, sexual reproduction is done by oogamy.

An example of red algae, Eucheuma spinosum, is the raw material for agar, gelidium and gracillaria.

Golden algae or Chrysophyta . Golden algae have a dominant pigment contained, namely xanthophyll or golden pigment. This golden alga does not have a pyenoid, and has a small size chloroplast.

Golden algae live in watery places, both fresh water and sea water. The structure of this golden algae body is in the form of a single cell and some are composed of many cells. One of the main members of this golden algae group is diatoms.

Diatoms are found in the sea, although some live in fresh water. In aquatic ecosystems, diatoms can act as phytoplankton so that their presence can be a heterotropic source of food and oxygen for living things.

Diatom structures often resemble boxes. This is due to the cell wall has two valves, namely large valves and small valves. This large valve or epitereka acts as a cover.

Meanwhile, this small or hypothermic valve is closed or as a base. Between the closed part and the lid there is a gap called the rafe.

Dead diatom cells generally settle to the bottom of the water. Then form diatomaceous earth on the seabed. Diatomaceous earth contains a lot of grit or silica originating from diatom cell walls.

Because of this, diatoms are often called grit algae. This grit can be used as a polishing agent. In addition, insulation materials, dynamite-making materials, filter-making materials, soundproofing materials, and toothpaste ingredients.

Diatoms can produce vegetatively and generatively. Vegetative reproduction is done by splitting themselves. Then, generative reproduction is done by fusing two gametes.

Vegetative reproduction in diatoms occurs in a way. At first the two halves of the valve, epitheka, and hypotension divide. Then, each of them carries the cytoplasm. Epithetical parts will form hypothetics.

Meanwhile, the hypothetical part will turn into epitheka which will then form a new hypothetical. This means, each valve originating from the first division will form a hypotension so as to produce new puppy cells in the form of boxes.

Its size is smaller than its parent. These events occur repeatedly so that the size of the diatom cell reaches a minimum size. If the diatom cell is too small and unable to divide again, the protoplasm will come out of the cell wall into a body called an auxospora.

Then the auxospores grow. When it reaches its original size it will form epitheka and hypekaeka.

In addition, another opinion states that this golden alga breeds sexually and asexually. Asexual reproduction is done by splitting or forming spores.

Furthermore, sexual reproduction is done by the union of two gametes. Examples of golden algae are Mischococcus, Synura, and Navicula.

Fire Algae or Pyrrophyta . Some fire algae can radiate light. This is due to the presence of phosphorus compounds. Being able to emit light, fire algae have phosphorescence properties.

This phosphorescence can cause the sea to look radiant at night. Because of this, it is called the fire algae.

Fire algae can also cause a ride tide. Ride tide is an event where sea water is brownish red. From this incident, algae produce poisons that can be used to kill fish and marine animals that are around it.

Thus an explanation of protists that resemble plants. The next discussion will describe protists that resemble mushrooms. Pay attention to the explanation below.

Mushroom-like Protists

The fungus that is meant is different from the actual fungus. The difference can be seen based on the characteristics shown. The characteristics of a fungus-like protist are as follows.

First, it has flagged cells at a certain time in its life cycle. Second, especially in aquatic fungi, the cell wall is composed of cellulose, not even kirin as well as in fungi.

Third, all members can form spores. Fourth, the relationship of living things in this group is not strong when viewed in evolution. In fact, some of them have similarities with Ameba. Examples of slime molds that are mobile with ameboid movements and obtain food by phagocytosis.

After understanding about the characteristics of fungal-like protists. Next, we will explain the classification of protists that resemble fungi, which consists of three phyla, namely the phylum Myxomycota, Acrasiomycota, and Oomycota.

Myxomycota phylum. The phylum Myxomycota is known as a plasmodial or acellular mucus fungus. These plasmodial mucus fungi generally live like plasmodium. This fungus has a mucous layer.

The mucous layer has phagocytic properties against plant material in forests or agricultural land. In unfavorable conditions, such as during the dry season, this plasmodium develops to form sporangia (singularly called sporangium).

Sporangium is a reproductive structure that is capable of producing spores. Collection of sporangium, called the fruit body. If conditions allow for growth, for example high humidity, the spores produced by sporangium will germinate.

During the germination process, the spores are then released in the form of flagged cells or ameboid cells. In the end, the two cell forms unite then form a zygote. Then grow to form plasmodium multimucleate again.

Phylum Acrasiomycota. The Acrasiomycota phylum is known as cellular phlegm. These cellular slime molds generally live in the soil. This fungus lives like individual ameboid cells.

The small size of the fungus makes it difficult to see cellular slime mold. If the food supply is reduced, the cells will release a chemical compound that can cause these fungi to form pseudoplasmodium.

This pseudoplasmodium stage is temporary. Then, it will eventually grow into a fruiting body and produce spores.

When conditions permit, spores germinate. This condition is characterized by the release of ameboid cells. In this case, the asexual cycle then begins again. Meanwhile, the sexual cycle occurs in very humid conditions.

Oomycota phylum. The oomycota phylum is known as the water fungus. This fungus lives as a parasite in fish and as a decomposer. Even though they are called water mushrooms, some water molds are able to live on land.

Those who live on land as parasites on various insects and plants. The water mushroom is responsible for any event of scarcity of potatoes in 1840 that occurred in the territory of Ireland.

In general, this water fungus has saprophytic properties and lives on organic matter that has died. Mushrooms have a mushroom-like body. However, most of the cell wall of this water fungus consists of cellulose.

Water mushroom life cycle is different from mushrooms in general. During asexual reproduction, aquatic fungi produce motile spores or 2n flagged zoospores. When adults are diploid, not haploid as occurs in fungi.

Meiotic division produces special gametes. The gametes are sperm and egg. Examples of aquatic fungi are Saprolegnia, Phytophtora infestans, and Plasmopara viticola.

Thus the explanation of the classification of fungal-like protists. The next discussion will explain the benefits of mushroom-like protists for life. Similar to algae and protozoa, fungal-like protists can also benefit human life.

The presence of water molds can increase nutrients in the aquatic ecosystem. This can be made possible because of its function as a saprofit or decomposer.

In the waters, water molds often look like fine threads on dead fish or organic material floating in water. Furthermore, besides providing benefits, some mushrooms also have adverse effects. One of them happens to potato plants.

Thus the presentation of protists. Mushroom-like protists, plant-like protists, and animal-like protists have been explained clearly in this article.

Where each type of protist is given a description of the characteristics and examples to give clear information to you. Hopefully this can help you in understanding protists. Happy learning and always successful.


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