The pseudopods are. The structure and life of the protozoa. The simplest living in sea water and soil and others

PART 4. The Animal Kingdom

Subkingdom Unicellular

OPTION 1

In each task, choose one correct answer from the four suggested.

A1. Almost all animals eat

1) autotrophic

2) heterotrophic

3) in the process of photosynthesis

4) in the process of chemosynthesis

A2. The nervous system is in the representatives of the kingdom

2) bacteria

3) plants

4) animals

AZ. The body consists of one cell

2) lichens

3) cap mushrooms

4) the simplest animals

A4. The pseudopods of the simplest animals are

1) plastids

2) nuclear matter

3) outgrowth of the cytoplasm

4) supply of nutrients

A5. The organoid of secretion of undigested food residues in protozoa is

4) powder

A6. Reproduction of the simplest animals mainly occurs by

1) phagocytosis

2) pinocytosis

3) cell division

4) cyst formation

A7. Constant body shape is absent in

1) foraminifera

2) ciliates-shoes

3) euglena green

4) common amoeba

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

1) chlorophyll

2) cytoplasm

A9. Two nuclei are found in animal cells

1) ciliates

2) euglena

3) volvox

B1.

A. Many of the simplest animals are part of the plankton.

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

1) Only A is true

2) Only B is true

3) Both statements are true

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 true

2) Only B is true

3) Both statements are true

4) Both judgments are wrong

BZ. Pick 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 appearance.

FEATURE OF THE BUILDING

A. Presence of cilia

B. light-sensitive peephole

B. Pseudopods

G. Chloroplast

D. Two cores

KIND OF ANIMAL

2) Euglena

3) Infusoria slipper

OPTION 2

A1.Unlike plants, most animals are characterized by

1) autotrophic nutrition

2) limited growth

3) unlimited growth

4) immobility

A2.Body symmetry is typical for

1) algae

2) animals

3) bacteria decay

4) moldy mushrooms

A3. Organ of locomotion of ciliates

2) cilia

3) limbs

4) muscle fiber

A4. Grabs food with pseudopods

2) euglena

3) amoeba

4) ciliates

A5.In adverse conditions, the simplest animals form

1) cyst

3) powder

4) contractile vacuole

A6. Excess water from the body of the simplest animal removes

2) pseudopod

3) contractile vacuole

4) light-sensitive peephole

A7. Special nutritional organelles are absent in

1) common amoeba

2) ciliates-shoes

3) euglena green

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 in ciliates is

1) pharynx

2) eyelash

3) small core

4) contractile vacuole

B1. Are the following statements true?

B. The simplest animals are able to reproduce sexually.

1) Only A is true

2) Only B is true

3) Both statements are true

4) Both judgments are wrong

B2. Are the following statements true?

A. Euglena green moves to illuminated places.

1) Only A is true

2) Only B is true

3) Both statements are true

4) Both judgments are wrong

BZ. Pick three true statements. For animals are characteristic features of life

1) limited growth

2) immobility

3) active movement

4) unlimited growth

5) nutrition with ready-made substances

6) the formation of substances in the light

B4. Establish a correspondence between the vital activity of the animal and its species.

THE PROCESS OF LIFE

A. Phagocytosis - food capture by pseudopods

B. Undigested residues are removed through powder

B, Photosynthesis

D. Movement with cilia

KIND OF ANIMAL

2) Euglena

3) Infusoria-shoe

Write down the corresponding numbers in the table.

The sub-kingdom of unicellular or protozoa includes the smallest creatures whose body consists of one cell. These cells represent an independent organism with all its characteristic functions (metabolism, irritability, movement, reproduction).

The body of unicellular organisms can have a constant (ciliate-shoe, flagellate) or an unstable shape (amoeba). The main body components of protozoa are nucleus and cytoplasm... In the cytoplasm of protozoa, along with general cellular organelles (mitochondria, ribosomes, Galdzhi apparatus, etc.), there are special organelles (digestive and contractile vacuoles) that perform the functions of digestion, osmoregulation, and excretion. Almost all protozoa are capable of active movement. The movement is carried out using pseudopods (in amoeba and other rhizopods), flagella (euglena green) or cilia (ciliates). Protozoa are able to capture solid particles (amoeba), which is called phagocytosis... Most protozoa feed on bacteria and decaying organic matter. Food after swallowing is digested in digestive vacuoles... The selection function in protozoa is performed by contractile vacuoles, or special holes - powder (in ciliates).

Protozoa live in fresh water, seas and soil. The vast majority of protozoa have the ability to encysting, that is, the formation of a dormant stage upon the onset of unfavorable conditions (lowering temperature, drying out of a reservoir) cystscovered with a dense protective shell. Cyst formation is not only an adaptation to survival under unfavorable conditions, but also to the spread of protozoa. Once in favorable conditions, the animal leaves the cyst membrane, begins to feed and reproduce.

Reproduction of protozoa occurs by dividing the cell into two (asexual); many have a sexual process. In the life cycle of most protozoa, asexual and sexual reproduction alternate.

There are over 90,000 unicellular species. All of them are eukaryotes (they have a separate nucleus), but they are at the cellular level of organization.

Amoeba

A representative of the rhizome class is amoeba ordinary. Unlike many protozoa, it does not have a constant body shape. It moves with the help of pseudopods, which also serve to capture food - bacteria, unicellular algae, some protozoa.

Having surrounded the prey with pseudopods, the food turns out to be in the cytoplasm, where a digestive vacuole forms around it. In it, under the influence of the digestive juice coming from the cytoplasm, digestion occurs, as a result of which digestive substances are formed. They enter the cytoplasm, and undigested food debris is thrown out.

Amoeba breathes with the entire surface of the body: oxygen dissolved in water, by diffusion, directly penetrates into its body, and carbon dioxide formed in the cell during breathing is released outside.

The concentration of dissolved substances in the body of the amoeba is greater than in water, so water is continuously accumulated and its excess is removed to the outside using contractile vacuole... This vacuole is also involved in the removal of decay products from the body. Amoeba reproduces by division. The nucleus divides in two, both halves diverge, a constriction is formed between them, and then two independent daughter cells arise from one mother cell.

Amoeba is a freshwater animal.

Euglena green

Another widespread species of the simplest animals lives in fresh water bodies - euglena green... It has a fusiform shape, the outer layer of the cytoplasm is compacted and forms a membrane that helps to maintain this shape.

A long thin flagellum departs from the front end of the body of green euglena, rotating which, euglena moves in water. In the cytoplasm of euglena, there is a nucleus and several colored oval bodies - chromatophorescontaining chlorophyll. Therefore, in the light, euglena eats like a green plant (autotrophic). A light-sensitive eye helps to find illuminated places for euglena.

If euglena is in the dark for a long time, then chlorophyll disappears and it switches to a heterotrophic method of nutrition, that is, it feeds on ready-made organic substances, sucking them out of the water with the entire surface of the body. Respiration, reproduction, division in two, cyst formation in euglena green are similar to those in amoeba.

Volvox

Colonial species are found among flagellates, for example, volvox.

Its shape is spherical, the body consists of a gelatinous substance, in which individual cells are immersed - members of the colony. They are small, pear-shaped, and have two flagella. Thanks to the coordinated movement of all flagella, the Volvox moves. There are few cells in the Volvox colony that are capable of reproducing; daughter colonies are formed from them.

Infusoria-shoe

In fresh water bodies, another type of protozoa is often found - ciliate shoe, which got its name due to the peculiarities of the shape of the cage (in the form of a shoe). Cilia serve as organelles of movement. The body has a constant shape, as it is covered with a dense shell. The ciliate shoe has two nuclei: a large and a small one.

Big core regulates all life processes, small - plays an important role in the reproduction of the shoe. Infusoria feeds on bacteria, algae and some protozoa. Through vibrations cilia food gets into mouth opening, then - in throat, at the bottom of which digestive vacuoleswhere food is digested and nutrients are absorbed. Undigested residues are removed through a special organ - powder... The selection function is carried out contractile vacuole.

It reproduces, like the amoeba, asexually, however, the sexual process is also characteristic of the ciliate-shoe. It consists in the fact that two individuals unite, an exchange of nuclear material occurs between them, after which they disperse (Fig. 73).

This type of sexual reproduction is called conjugation... Thus, among freshwater protozoa, the slipper has the most complex structure.

Irritability

When characterizing the simplest organisms, special attention should be paid to one more of their properties - irritability... Protozoa do not have a nervous system, they perceive irritations of the entire cell and are able to respond to them with movement - taxismoving in the direction of the stimulus or away from it.

The simplest living in sea water and soil and others

Soil protozoa are representatives of amoebas, flagellates and ciliates, which play an important role in the soil-forming process.

In nature, protozoa participate in the circulation of substances, perform a sanitary role; in food chains are one of the first links, being food for many animals, in particular fish; take part in the formation of geological rocks, and their shells determine the age of individual geological rocks.

Answers to school textbooks

Characteristic features of the structure of unicellular animals:

Most are microscopic;

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

The cytoplasm is limited by a membrane that can be covered by a cell membrane or shell;

Some species contain several nuclei in the 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 through the entire body surface by diffusion; undigested food debris is thrown out of the vacuole;

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

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

In unfavorable conditions, they form a cyst (a dense membrane is isolated on the surface, which allows the cell to be maximally protected from external influences).

2. Prove that the plan of the body structure 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 the main parts: nucleus, cytoplasm and plasma membrane;

The cytoplasm contains multi-member 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 inner skeleton of the cell.

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

In sarcodes, pseudopods, pseudopodia, are formed, if necessary, to move and capture food. They are outgrowths of the cytoplasm, strengthened by the fibers of the cytoskeleton.

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

In freshwater species, the excretory and osmoregulating function is performed by the contractile vacuole.

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

4. Which group of unicellular animals is the most ancient?

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

5. Tell us about the types of food found in flagellates.

By the way of nutrition, flagellates are divided into three groups:

Autotrophic organisms that synthesize organic matter (carbohydrates) using the energy of sunlight, that is, they feed like real plants (all colored flagella);

Heterotrophic organisms using 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 they also feed on organic substances, absorbing bacteria and other protozoa by phagocytosis (euglena green).

6. What animals do not have a permanent body shape?

Due to the underdeveloped and very mobile skeleton of the cell, formed by protein fibers and microtubules, many sarcophagus (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, unicellular animals reproduce asexually - by cell division, and when unfavorable conditions occur - sexually.

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

Many protozoa play a significant role in the food webs of the reservoir: they absorb 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 chalk layers.

9. What are pseudopodia?

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

10. Can protozoa have shells?

Yes. The body of shell amoebae and foraminifera is enclosed in a single-chambered shell, equipped with an opening - an opening through which pseudopodia emerge into the environment. Shells are composed of a chitin-like substance and can be of various shapes. In some representatives, the shells are purely organic, in others they are impregnated with calcium salts or inlaid with grains of sand.

11. What are the main features of the organization of foraminifera.

Foraminifera are mostly represented by marine rhizopods.

The main features of the foraminifer organization:

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

Pseudopodia are pulled out from the shell, allowing movement and food capture.

12, Which protozoa have skeletal formations?

All eukaryotic cells have a cytoskeleton. In some cases, it is poorly expressed (like in rhizomes). In other representatives, the cell skeleton ensures the maintenance of a constant body shape over a long life cycle. The cytoskeleton is most pronounced in ciliates. The constant shape of the body is provided by thick bundles of cytoskeleton fibers adjacent to the membrane.

13, What organisms are called autotrophic?

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

Autotrophs-photosynthetics form organic matter (carbohydrates) from carbon dioxide and water due to the energy of solar radiation.

Autotrophs-chemosynthetics form organic molecules from inorganic ones due to the energy of chemical bonds of inorganic molecules.

14. What are colonies and how are they formed in protozoa?

Colonies are large or small clusters of cells in unicellular organisms. Colony cells have no permanent specialization. Colonies can form as a result of the division of individual cells that do not move away from each other and continue to coexist. Also, colonies can form as a result of incomplete cell division, when individuals that are not completely separated from each other remain connected. Colonies differ in form and mode of development. The number of individuals included in the colony ranges from 4 to 20 thousand cells.

In their structure, protozoa are extremely diverse. The smallest ones have a diameter of 2-4 microns (a micrometer is 0.001 mm). Their most common sizes are in the range of 50-150 microns, some reach 1.5 mm and are visible with the naked eye.

The amoeba has the simplest structure. The body of the amoeba is a lump of semi-liquid cytoplasm with a nucleus in the middle. The entire cytoplasm is subdivided into two layers: outer, viscous - ectoplasm and inner, much more liquid - endoplasm. These two layers are not sharply demarcated and can transform into each other. The amoeba does not have a hard shell, and it is able to change the shape of the body. When an amoeba crawls on a leaf of an aquatic plant, bulges of cytoplasm are formed in the direction in which it moves. Gradually, the rest of the amoeba cytoplasm flows into them. Such protrusions are called pseudopods or pseudopodia. With the help of pseudopodia, the amoeba not only moves, but also captures food. With pseudopodia, it covers a bacterium or microscopic alga, soon the prey is inside the body of the amoeba, and a bubble forms around it - a digestive vacuole. Undigested food residues are thrown out after a while.

Amoeba proteus: 1 - core; 2 - digestive vacuoles; 3 - contractile vacuole; 4 - pseudopods; 5 - undigested food debris thrown out.

In the cytoplasm of the amoeba, a light bubble is usually visible, which appears and disappears. This is a contractile vacuole. It collects excess water that accumulates in the body, as well as the liquid waste products of the amoeba. Amoeba breathes, like all other protozoa, the entire surface of the body.

Euglena green: 1 - flagellum; 2 - an eye spot; 3 - contractile vacuole;

The most complex structure of the protozoa in ciliates. Unlike the amoeba, their body is covered with the thinnest shell and has a more or less constant shape. Support and shape of the body is also supported by supporting fibers running in different directions. However, the body of ciliates can quickly contract, change its shape, and then return to its original shape. The contraction is carried out with the help of special fibers, similar in many respects to the muscles of multicellular animals.

Infusoria shoe: 1 - cilia; 2 - digestive vacuoles; 3 - large nucleus (macronucleus); (micronucleus); 5 - mouth opening and pharynx; 6 - undigested food debris thrown out; 7 - trichocysts; 8 - contractile vacuole.

Ciliates can move very quickly. So, a shoe in a second overcomes a distance exceeding the length of its body by 10-15 times. At the same time, a lot of cilia that cover the entire body of the ciliate perform fast rowing movements, up to 30 per second (at room temperature). In the ectoplasm of the shoe, there are many trichocyst rods. When irritated, they are thrown outward, turning into long threads, and hit the enemy who attacks the ciliates. Instead of those thrown out in the ectoplasm, new trichocysts are formed. On one side, approximately in the middle of the body, the shoe has a deep oral cavity leading into a small tubular pharynx. Through the pharynx, food enters the endoplasm, where it is digested in the formed digestive vacuole. In ciliates, unlike amoebas, undigested food debris is thrown away at a certain place in the body. Their contractile vacuole is more complex and consists of a central reservoir and conducting channels. The ciliate has two types of nuclei: large - macronucleus and small - micronucleus. Some ciliates may have several macro- and micronuclei. The macronucleus differs from the micronucleus in a significantly larger number of chromosomes. And therefore, it contains a lot of deoxyribonucleic acid (DNA), which is part of the chromosomes.

Various types of ciliates: 1 - ciliate trumpeter; 2-5 - planktonic ciliates.

The simplest are irritable and therefore are able to choose the most favorable environmental conditions for themselves, reacting to light, heat, various chemicals, electric current, magnetic field and other irritants.

Under unfavorable conditions, for example, when the reservoir dries up or freezes, protozoa take a spherical shape, lose cilia or flagella, form a hard shell on their surface and turn into an immobile cyst. Protozoan cysts survive both drying out and sudden changes in temperature. Cysts are easily carried by the wind, with grass, hay, etc., which contributes to the dispersal of the species. If the cyst is in suitable conditions, its membrane bursts or holes appear in it, and the body goes on to active existence.

A basic level of

In each task, choose one correct answer from the four suggested.

A1. Almost all animals eat

1. autotrophically
2. heterotrophic
3. in the process of photosynthesis
4. in the process of chemosynthesis

A2. The nervous system is in the representatives of the kingdom

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

AZ. The body consists of one cell

1. lichens
2. cap mushrooms
3. simplest animals

A4. The pseudopods of the simplest animals are

1. plastids
2. nuclear matter
3. cytoplasmic outgrowth
4. supply of nutrients

A5. The organoid of secretion of undigested food debris in protozoa is

1. cyst
2. flagellum
3. powder

A6. Reproduction of the simplest animals mainly occurs by

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

A7. Constant body shape is absent in

1. foraminifera
2. ciliates-shoes
3. euglena green
4. common amoeba

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

1. chlorophyll
2. cytoplasm
3. flagellum

A9. Two nuclei are found in animal cells

1. ciliates
2. euglena
3. volvox
4. amoeba

- - - 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 of the simplest animals are part of the plankton.
B. Phagocytosis of protozoa is associated with the formation of a contractile vacuole.

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

BZ. Pick 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 appearance.

Feature of the structure

A. Presence of cilia
B. Light-sensitive eye
B. Pseudopods
G. Chloroplast
D. Two cores

Kind of animal

1. Amoeba
2. Euglena
3. Infusoria-shoe

Write down the corresponding numbers in the table.

- - - Answers - - -

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