The pseudopods of protozoan animals are plastids. Protozoa

Answers to school textbooks

Characteristic structural features of unicellular animals:

Most are microscopic in size;

The body consists of a single cell and is a whole organism with many inherent functions;

The cytoplasm is bounded by a membrane, which may be covered by a cell membrane or shell;

Some species contain several nuclei per cell;

There are organelles of movement - flagella, cilia or pseudopods, which can be temporary or permanent;

The digestive vacuole, formed as a result of pinocytosis or phagocytosis, carries out digestion. The vacuole may be absent in species that absorb nutrients throughout the body surface by diffusion; undigested food remains are thrown out of the vacuole;

The contractile (otherwise called excretory, pulsating, osmoregulatory) vacuole performs an excretory and osmoregulatory function; it is found only in freshwater species;

There are no special respiratory organs; respiration occurs due to the diffusion of gases through the cell surface;

Under unfavorable conditions, they form a cyst (a dense shell is released onto the surface, which allows the cell to be maximally protected from external influences).

2. Prove that the body plan of unicellular organisms corresponds to the general features of the organization of nuclear (eukaryotic) cells.

All eukaryotic cells, both unicellular and multicellular organisms, are characterized by:

The presence of main parts: nucleus, cytoplasm and plasma membrane;

The cytoplasm contains multi-membered organelles that perform special functions: endoplasmic reticulum, Golgi apparatus, mesosomes, ribosomes, mitochondria;

Plastids (in plants and some unicellular organisms), cell center, basal bodies of flagella and cilia;

The cell nucleus is surrounded by a nuclear envelope consisting of two membranes;

Any eukaryotic cell has a cytoskeleton - a system of microtubules and protein fibers that form the internal framework of the cell.

3. What special-purpose organelles are found in unicellular organisms?

In sarcodidae, to move and capture food, if necessary, pseudopods are formed - pseudopodia. They are outgrowths of the cytoplasm reinforced by cytoskeletal fibers.

Flagellates move with the help of one or more flagella, and ciliates move with the help of numerous cilia.

In freshwater species, the excretory and osmoregulatory functions are performed by the contractile vacuole.

In flagellates, the ability to move directionally under the influence of light is due to the activity of the light-sensitive eye - the stigma.

4. Which group of single-celled animals is the most ancient?

The most ancient classes are Flagellates and Sarcodaceae. This is evidenced by the relative simplicity of their organization.

5. Explain the types of nutrition found in flagellates.

According to the method of feeding, flagellates are divided into three groups:

Autotrophic organisms that synthesize organic substances (carbohydrates) using the energy of sunlight, i.e., they feed like real plants (all colored flagellates);

Heterotrophic organisms that use organic substances that have already been created by other organisms (colorless flagellates);

Mixotrophic organisms with a mixed type of nutrition, they are capable of photosynthesis, but also feed on organic substances, absorbing bacteria and other protozoa by phagocytosis (green euglena).

6. Which animals do not have a constant body shape?

Due to the underdeveloped and very mobile skeleton of the cell, formed by protein fibers and microtubules, many sarcoflagellates (for example, amoeba) do not have a constant body shape. In addition, rapid rearrangements of the internal frame make it possible to easily change the shape of the body and quickly form pseudopodia.

7. How do protozoa reproduce?

As a rule, under favorable conditions, single-celled animals reproduce asexually - by cell division, and under unfavorable conditions - sexually.

8. What is the role of protozoa in nature? In human life?

Many protozoa play a significant role in the food chains of a reservoir: they consume bacteria and some algae, and themselves, in turn, serve as food for many invertebrates, fish fry, and tadpoles.

In the seas and oceans, the shells of dead rhizomes, settling to the bottom, form layers of chalk.

9. What are pseudopodia?

Pseudopodia (pseudopods) are organelles of movement. They are outgrowths of the cytoplasm reinforced by cytoskeletal elements.

10. Can protozoans have shells?

Yes. The body of testate amoebae and foraminifera is enclosed in a single-chamber shell equipped with an opening - the mouth, through which pseudopodia emerge into the environment. The shells consist of a chitin-like substance and can have a variety of shapes. Some representatives have purely organic shells, others are impregnated with calcium salts or encrusted with grains of sand.

11. Name the main features of the organization of foraminifera.

Foraminifera are mostly represented by marine rhizomes.

The main features of the foraminiferal organization:

They have a multi-chamber shell consisting of calcium carbonate (due to which their remains form chalk deposits);

Pseudopodia extend from the shell to enable locomotion and food capture.

12. What protozoa have skeletal structures?

All eukaryotic cells have a cytoskeleton. In some cases it is weakly expressed (as in rhizomes). In other representatives, the cell skeleton ensures the maintenance of a constant body shape throughout the life cycle. The cytoskeleton is most clearly expressed in ciliates. The constant shape of the body is ensured by thick bundles of cytoskeletal fibers adjacent to the membrane.

13. What organisms are called autotrophic?

Organisms that are capable of synthesizing organic substances from inorganic ones are called aetotrophic.

Photosynthetic autotrophs form organic substances (carbohydrates) from carbon dioxide and water using the energy of solar radiation.

Chemosynthetic autotrophs form organic molecules from inorganic ones due to the energy of chemical bonds of inorganic molecules.

14. What are colonies and how do they form in protozoa?

Colonies are large or small collections of cells of single-celled organisms. Colony cells do not have constant specialization. Colonies can be formed as a result of the division of individual cells that do not move away from each other and continue to exist together. Colonies can also form as a result of incomplete cell division, when individuals that have not completely separated from each other remain connected to each other. Colonies differ in both form and method of development. The number of individuals that make up a colony ranges from 4 to 20 thousand cells.

A basic level of

For each task, choose one correct answer from the four proposed.

A1. Almost all animals eat

1. autotrophic
2. heterotrophic
3. during photosynthesis
4. during chemosynthesis

A2. Representatives of the kingdom have a nervous system

1. mushrooms
2. bacteria
3. plants
4. animals

AZ. The body is made up of one cell

1. lichens
2. cap mushrooms
3. protozoa

A4. The pseudopods of protozoan animals are

1. plastids
2. nuclear matter
3. growth of cytoplasm
4. nutrient supply

A5. The organelle for excreting undigested food debris in protozoa is

1. cyst
2. flagellum
3. powder

A6. Reproduction of protozoa occurs mainly through

1. phagocytosis
2. pinocytosis
3. cell division
4. cyst formation

A7. There is no permanent body shape

1. foraminifera
2. ciliates-slippers
3. euglena green
4. amoeba vulgaris

A8. Only in the cells of the simplest animals that feed autotrophically, there is

1. chlorophyll
2. cytoplasm
3. flagellum

A9. Two nuclei are found in animal cells

1. ciliates
2. euglena
3. Volvox
4. amoebas

- - - Answers - - -

A1-2; A2-4; A3-4; A4-3; A5-4; A6-3; A7-4; A8-1; A9-1.

Increased difficulty level

B1. Are the following statements true?

A. Many simple animals are part of plankton.
B. Phagocytosis of protozoa is associated with the formation of a contractile vacuole.

1. Only A is correct
2. Only B is correct
3. Both judgments are correct
4. Both judgments are wrong

B2. Are the following statements true?

A. Amoeba captures food with pseudopods.
B. Among the representatives of the simplest animals, there are multicellular organisms.

1. Only A is correct
2. Only B is correct
3. Both judgments are correct
4. Both judgments are wrong

BZ. Choose three true statements. Absent in animal cells

1. cell wall
2. chloroplast
3. cytoplasm
4. outer membrane
5. large vacuole

B4. Establish a correspondence between the structural feature of the animal and its species.

Features of the structure

A. Presence of cilia
B. Photosensitive eye
B. Psepododes
G. Chloroplast
D. Two cores

Kind of animal

1. Amoeba
2. Euglena
3. Ciliate slipper

Write down the corresponding numbers in the table.

- - - Answers - - -

B1-1; B2-1; B3-126; B4-32123.

Type Protozoa. Classification, lifestyle, structural features, reproduction and development.

Unicellular animals include animals whose body morphologically corresponds to one cell, being at the same time an independent organism with all the functions inherent in the body.

Protozoa are organisms at the cellular level of organization. Morphologically, their body is equivalent to a cell, but physiologically it represents a whole independent organism. The vast majority of them are microscopically small in size. The total number of known species exceeds 30,000.

The structure of protozoa is extremely diverse, but they all have features characteristic of the organization and function of the cell. The two main components of the protozoan body are the cytoplasm and the nucleus. The cytoplasm is bounded by an outer membrane, which is about 7.5 nm thick and consists of three layers, each about 2.5 nm. This main membrane, consisting of proteins and lipids and regulating the flow of substances into the cell, in many protozoa is complicated by additional structures that increase the thickness and mechanical strength of the outer layer of the cytoplasm. Thus, formations such as pellicles and membranes arise.

The cytoplasm of protozoa usually splits into two layers - the outer, lighter and denser - ectoplasm and the inner, equipped with numerous inclusions - endoplasm. General cellular organelles are localized in the cytoplasm: mitochondria, endoplasmic reticulum, ribosomes, elements of the Golgi apparatus. In addition, a variety of special organelles may be present in the cytoplasm of many protozoa. Various fibrillar formations are especially widespread - supporting and contractile fibers, contractile vacuoles, digestive vacuoles, etc. Protozoa have a typical cell nucleus, one or more. The nucleus of protozoa has a typical two-layer nuclear envelope, permeated with numerous pores. The contents of the nucleus consists of nuclear juice (karyoplasm), in which chromatin material and nucleoli are distributed. Chromatin is a despiralized chromosome composed of DNP - deoxynucleoproteins, in turn consisting of deoxyribonucleic acid (DNA) and proteins such as histones. Nucleoli, which can be one, several or many, are clusters of ultramicroscopic ribosome-type granules, consisting of ribonucleic acid (RNA) and proteins. The nuclei of protozoa are characterized by exceptional morphological diversity. They vary in size, amount of karyoplasm, number and nature of distribution of nucleoli, their location in the nucleus, relation to the centrosome (cell center), etc.

The life cycle consists of a number of successive stages, which are repeated with a certain pattern in the existence of each species. This phenomenon is called cyclicity, and the period of life of a species between two unambiguous stages constitutes its life cycle. Most often, the cycle begins with the zygote stage, corresponding to the fertilized egg of multicellular organisms. This stage is followed by single or multiple repeated asexual reproduction, carried out by cell division. This is followed by the formation of germ cells (gametes), the pairwise fusion of which again produces a zygote. The latter either directly turns into the vegetative stage, or is previously divided one or more times.

An important biological feature of many protozoa is the ability to encyst. At the same time, animals become rounded, shed or retract organelles of movement, secrete a dense shell on their surface and pass from active life to a state of rest. In the encysted state, protozoa can tolerate sudden changes in the environment (drying, cooling, etc.) while maintaining viability. When conditions favorable for life return, the cysts open and the protozoa emerge from them in the form of active, mobile individuals.

Protozoa perceive various changes in the external environment: temperature, chemical, light, mechanical, etc. Some external influences cause a positive reaction in them, i.e. movement towards the source of irritation, others – negative, i.e. movement away from the source of irritation. These directed movements of free-living organisms that do not have nervous apparatus are called taxis.

Most protozoa can move slowly or quickly. The methods of movement in different classes of this type are different. The most common methods of locomotion are using pseudopods, or pseudopodia, flagella and cilia. Pseudopes are temporary protrusions of the cytoplasm, the shape and length of which are different and characteristic of each species or group of species. Releasing the pseudopods, the animal slowly crawls, while the shape of its body changes all the time. Flagella are long, thin outgrowths of the outer layer of the cytoplasm that describe a cone during their movement. Each flagellum contains 11 longitudinal fibers (fibrils), of which 2 are central and 9 are peripheral. The inner fibers perform a supporting function, and the outer fibers perform a motor function. Flagella begin from special formations - kinetosomes. Metabolic processes occurring in kinetosomes are the source of energy necessary for the movement of flagella. Cilia are very similar in structure to flagella, but unlike the latter they are short and work like oars; their number is usually large. Other methods of movement of protozoa are also known: as a result of contraction of special fibers (myonemes), by secreting fluid from the back of the body (reactive method of movement), etc.

Dissimilation products are secreted in protozoa through the entire surface of the body, and in many through contractile, or pulsating, vacuoles. These organelles are light, transparent vesicles that periodically fill with liquid to a certain limit, then collapse when it is released out. The main function of contractile vacuoles is to remove excess water from the cell.

In all classes of protozoa, sexual reproduction is observed. In most cases, it is carried out by fusion (copulation) of a microgamete with a macrogamete. In ciliates, the sexual process occurs in the form of conjugation.

In protozoa, which arose as a result of different methods of reproduction, the structure differs to some extent from the parental forms and not all organelles are present in the required quantity (for example, out of two contractile vacuoles, one may remain). Restoration of the normal structure and missing organelles occurs in the process of rapid ontogenetic development.

The type is divided into six classes:

Class Flagellates;

Class pseudopods, or sarcodes;

Class Sporozoans;

Class mucous sporozoans;

Class Microsporidia;

Ciliate class.

Class Flagellates

These protozoa move using flagella. The body shell is dense, which gives a certain shape to their body and facilitates rapid movement. However, in some flagellates, the shell is very thin and they move slowly, pouring their entire body into temporary outgrowths of the body - pseudopods, or pseudopodia. These forms, along with pseudopods, also have flagella. Many representatives have external skeletons made of fiber or other substances. In forms that are constantly in the water column, the skeleton often has long outgrowths that increase the surface of the body. This slows down the dive and makes it easier to float in the water.

Among flagellates there are both herbivorous and animal-eating forms, as well as mixotrophs, which can feed both as autotrophs and as heterotrophs.

Chlorophyll in autotrophic flagellates is located in plastids, or chromatophores. Autotrophic flagellates often have special eyes with pigment, many with red. Thanks to their eyes, these protozoa look for illuminated places where photosynthesis can occur in their cells.

Flagellates always divide longitudinally - along the long axis of the body. In many forms, the sexual process alternates with asexual reproduction. In a number of flagellates, daughter individuals do not separate after division, but remain together, as a result of which colonies are formed. The shape of the colonies is different: in sessile forms it is tree-shaped, in floating forms it is spherical.

plant flagellates;

flagellated animals.

Class pseudopods, or sarcodes

A characteristic feature of representatives of this class is movement with the help of temporary outgrowths - pseudopods (pseudopodia), the formation of which is possible due to the absence of pellicles in sarcodidae. The shape of the pseudopods is varied. Among pseudopods there are forms that have, in addition to pseudopodia, flagella.

Rhizomes are part of many marine sediments, starting with the most ancient Cambrian ones. Thick layers of limestone, chalk, green sandstone and some other sedimentary rocks consist mainly of foraminiferal shells.

Pseudophods feed on various microorganisms (bacteria, algae and organic debris, which they capture with pseudopodia). Pseudophods live mainly on the bottom or on the surface of various underwater objects, but there are representatives living in the water column and in the soil.

Sporozoan class

Adult sporozoans are usually inactive or move very slowly (using contractile fibers - myonemes, or secreting a thick liquid through tiny pores at the posterior end of the body). A number of sporozoans have rather thin shells. Gametes in many species have flagella. There are no contractile vacuoles. Sporozoans feed by absorbing dissolved organic and other substances over the entire surface of the body. They destroy host tissues and poison them with the products of their metabolism. Asexual reproduction often alternates with sexual reproduction. The development of sporozoans in many species is accompanied by a change of hosts.

The class is divided into two subclasses: coccidiformes and gregarines.

The first subclass is divided into:

Order blood sporozoans, or hemosporidia. Unlike coccidia, their sexual reproduction occurs in some hosts (various types of mosquitoes), and asexual reproduction in others (birds, mammals, humans). Hemosporidia can cause malaria.

In the mosquito intestine, gametocytes transform into mature germ cells - micro- and macrogametes. Narrow, mobile microgametes fertilize round, sedentary macrogametes, and zygotes are formed. The zygotes of hemosporidia are mobile, they are called ookinetes. The latter, having penetrated the intestinal walls, grow strongly, become covered with an elastic capsule and turn into oocysts. In the oocyst, under the protection of its shell, division occurs into a huge number of sporozoites. Eventually, the oocyst bursts and the sporozoites enter the mosquito's bloodstream and are carried into its salivary glands.

Piroplasmid order. These protozoa spend one part of their life cycle in the organisms of mammals, and the other in the organisms of blood-sucking pasture ticks.

Order meat sporozoans. They are often found as fairly large sac-shaped cysts, mainly in the muscles of mammals and birds.

The anterior end of the body of most gregarines forms an organelle of attachment to the intestinal wall - epimerite. Externally, the body is covered with a pellicle forming longitudinal ridges, representing the outer dense layer of ectoplasm. Under the pellicle lies a layer of ectoplasm, which in many gregarines, approximately at the border of the anterior third of the body, forms a fibrous septum separating the anterior, nucleusless section of the cytoplasm, called protomerite. The posterior large part of the body equipped with a nucleus is called deuterite. Thus, many gregarines, while remaining unicellular, become three-membered.

Nutrition and breathing are carried out over the entire surface of the body.

Class mucous sporozoans

Class Microsporidia

Some microsporidia lead to mass death of silkworm caterpillars, causing a disease called pebrina. Another species of the same genus causes "diarrhea" in bees.

Ciliate class

Ciliates are the most complex protozoa. On the outside there is a pellicle, consisting of two double membranes separated by a lumen, and in many ciliates it is delimited into cells by hard bridges, which increases its strength. In the outer layer of the cytoplasm of many ciliates there are rod-shaped trichocysts abutting the pellicle. Under the influence of irritations, trichocysts turn into long threads that are thrown out and penetrate the cells of other organisms. The movement is ensured by the coordinated work of the cilia. They extend from the basal bodies and penetrate the pellicle; special fibers are associated with them, playing a supporting role for the ciliary apparatus.

In fusoria, unlike other protozoa, there are two types of nuclei: large nuclei, or macronuclei, and small nuclei, or micronuclei. Almost always one individual has one macronucleus and one micronucleus; only some species have two or more small nuclei.

Ciliates reproduce by asexual (transverse division into two equal cells) and sexual (conjugation) methods.

Free-living ciliates are found in both fresh waters and seas. Their lifestyle is varied. Some ciliates are planktonic organisms, freshwater and marine. There are a large number of marine and freshwater species of benthic ciliates. They crawl along the bottom, aquatic plants, etc. Coastal sea sand is very rich in ciliates.

Free-living ciliates play a significant role in the food chains of a reservoir as eaters of bacteria and some algae. In turn, they serve as food for many invertebrates, as well as fish fry that have just hatched from eggs.

PART 4. Animal Kingdom

Subkingdom Unicellular

OPTION 1

For each task, choose one correct answer from the four proposed.

A1. Almost all animals eat

1) autotrophic

2) heterotrophic

3) in the process of photosynthesis

4) in the process of chemosynthesis

A2. Representatives of the kingdom have a nervous system

2) bacteria

3) plants

4) animals

AZ. The body is made up of one cell

2) lichens

3) cap mushrooms

4) protozoa

A4. The pseudopods of protozoan animals are

1) plastids

2) nuclear matter

3) growth of cytoplasm

4) supply of nutrients

A5. The organelle for excreting undigested food debris in protozoa is

4) powder

A6. Reproduction of protozoa occurs mainly through

1) phagocytosis

2) pinocytosis

3) cell division

4) cyst formation

A7. There is no permanent body shape

1) foraminifera

2) ciliates-slippers

3) green euglena

4) common amoeba

A8. Only in the cells of the simplest animals that feed autotrophically, there is

1) chlorophyll

2) cytoplasm

A9. Two nuclei are found in animal cells

1) ciliates

2) euglena

3) Volvox

B1.

A. Many simple animals are part of plankton.

B. Phagocytosis of protozoa is associated with the formation of a contractile vacuole.

1) Only A is correct

2) Only B is correct

3) Both judgments are correct

4) Both judgments are incorrect

B2. Are the following statements true?

A. Amoeba captures food with pseudopods.

B. Among the representatives of the simplest animals, there are multicellular organisms.

1) Only A is correct

2) Only B is correct

3) Both judgments are correct

4) Both judgments are incorrect

BZ. Choose three true statements. Absent in animal cells

1) cell wall

2) chloroplast

3) cytoplasm

5) outer membrane

6) large vacuole

B4. Establish a correspondence between the structural feature of the animal and its species.

BUILDING FEATURES

A. Presence of cilia

B. photosensitive peephole

B. pseudopods

G. Chloroplast

D. Two cores

KIND OF ANIMAL

2) Euglena

3) Ciliate slipper

OPTION 2

A1. Unlike plants, most animals have

1) autotrophic nutrition

2) limited growth

3) unlimited growth

4) immobility

A2. Body symmetry is characteristic of

1) algae

2) animals

3) bacteria rotting

4) moldy mushrooms

A3. Organ of locomotion of ciliates

2) eyelashes

3) limbs

4) muscle fiber

A4. Captures food with pseudopods

2) euglena

3) amoeba

4) ciliates

A5. In unfavorable conditions, protozoa form

1) cyst

3) powder

4) contractile vacuole

A6. Excess water is removed from the body of a protozoan animal

2) pseudopod

3) contractile vacuole

4) photosensitive peephole

A7. There are no special nutritional organelles in

1) common amoeba

2) ciliates-slippers

3) green euglena

4) Volvox

A8. Organisms that are capable of photosynthesis and feed on ready-made substances are called

1) autotrophs

2) heterotrophs

3) mixotrophs

4) photosynthetic

A9. The digestive organ of ciliates is

1) pharynx

2) eyelash

3) small core

4) contractile vacuole

B1. Are the following statements true?

B. Protozoa are capable of reproducing sexually.

1) Only A is correct

2) Only B is correct

3) Both judgments are correct

4) Both judgments are incorrect

B2. Are the following statements true?

A. Euglena green moves to illuminated places.

1) Only A is correct

2) Only B is correct

3) Both judgments are correct

4) Both judgments are incorrect

BZ. Choose three true statements. Animals have characteristic features of life activity

1) limited growth

2) immobility

3) active movement

4) unlimited growth

5) nutrition with prepared substances

6) formation of substances in the light

B4. Establish a correspondence between the life process of an animal and its species.

LIFE PROCESS

A. Phagocytosis - food capture by pseudopods

B. Undigested residues are removed through powder

B, Photosynthesis

D. Movement using cilia

KIND OF ANIMAL

2) Euglena

3) Ciliates-slipper

Write down the corresponding numbers in the table.

The common amoeba (kingdom Animals, subkingdom Protozoa) has another name - Proteus, and is a representative of the class Sarcodidae free-living. It has a primitive structure and organization, moves with the help of temporary growths of cytoplasm, more often called pseudopods. Proteus consists of only one cell, but this cell is a complete independent organism.

Habitat

The structure of an ordinary amoeba

The common amoeba is an organism consisting of one cell leading an independent existence. The body of the amoeba is a semi-liquid lump, 0.2-0.7 mm in size. Large individuals can be seen not only through a microscope, but also with a regular magnifying glass. The entire surface of the body is covered with cytoplasm, which covers the nucleus pulposus. During movement, the cytoplasm constantly changes its shape. Stretching out in one direction or the other, the cell forms processes, thanks to which it moves and feeds. Can push off algae and other objects using pseudopods. So, in order to move, the amoeba extends the pseudopod in the desired direction and then flows into it. The movement speed is about 10 mm per hour.

Proteus does not have a skeleton, which allows it to take any shape and change it as needed. The respiration of the common amoeba is carried out over the entire surface of the body; there is no special organ responsible for the supply of oxygen. During movement and feeding, the amoeba captures a lot of water. Excess of this fluid is released using a contractile vacuole, which bursts, expelling water, and then forms again. The common amoeba has no special sensory organs. But she tries to hide from direct sunlight and is sensitive to mechanical irritants and some chemicals.

Nutrition

Proteus feeds on single-celled algae, rotting debris, bacteria and other small organisms, which it captures with its pseudopods and pulls into itself so that the food ends up inside the body. Here a special vacuole is immediately formed, into which digestive juice is released. Amoeba vulgaris can feed anywhere in the cell. Several pseudopods can simultaneously capture food, then digestion of food occurs in several parts of the amoeba at once. Nutrients enter the cytoplasm and are used to build the amoeba’s body. Particles of bacteria or algae are digested, and the remaining waste is immediately removed outside. The common amoeba is capable of throwing out unnecessary substances in any part of its body.

Reproduction

Reproduction of the common amoeba occurs by dividing one organism into two. When the cell has grown sufficiently, a second nucleus is formed. This serves as a signal for division. The amoeba stretches out, and the nuclei disperse on opposite sides. A constriction appears approximately in the middle. Then the cytoplasm in this place bursts, so two separate organisms arise. Each of them contains a core. The contractile vacuole remains in one of the amoebas, and a new one appears in the other. During the day, the amoeba can divide several times. Reproduction occurs in the warm season.

Cyst formation

With the onset of cold weather, the amoeba stops feeding. Its pseudopods are retracted into the body, which takes the shape of a ball. A special protective film is formed on the entire surface - a cyst (of protein origin). Inside the cyst, the organism is in hibernation and does not dry out or freeze. The amoeba remains in this state until favorable conditions occur. When a reservoir dries out, cysts can be carried over long distances by the wind. In this way, amoebas spread to other bodies of water. When warmth and suitable humidity arrive, the amoeba leaves the cyst, releases its pseudopods and begins to feed and reproduce.

Place of amoeba in wildlife

The simplest organisms are a necessary link in any ecosystem. The importance of the common amoeba lies in its ability to regulate the number of bacteria and pathogens on which it feeds. The simplest single-celled organisms eat rotting organic remains, maintaining the biological balance of water bodies. In addition, the common amoeba is food for small fish, crustaceans, and insects. And those, in turn, are eaten by larger fish and freshwater animals. These same simple organisms serve as objects of scientific research. Large accumulations of unicellular organisms, including the common amoeba, participated in the formation of limestone and chalk deposits.

Amoeba dysentery

There are several varieties of protozoan amoebas. The most dangerous for humans is the dysenteric amoeba. It differs from the ordinary one in having shorter pseudopods. Once in the human body, dysenteric amoeba settles in the intestines, feeds on blood and tissues, forms ulcers and causes intestinal dysentery.