Type simplest (protozoa). The simplest type that appeared at the simplest

Who are the simplest?

The simplest, or eukaryotes are microscopic organisms with the cellular type of organization, previously they were a whole kingdom of living organisms, now in biology they are related to animal-like protists. Despite the fact that the body of the simplest is represented by one cell, they are independent organisms with all the main functions.

The bulk of eukaryotes has microscopic dimensions. No wonder the study of the simplest began at about the same time when a microscope was invented in the world, namely at the beginning of the XVII century. The Netherlands Naturalist Anton Levengook is considered the primary reproductor of the whole kingdom of wildlife, in 1675 examining a water drop in his microscope, he discovered a number of unknown science of organisms, among whom were representatives of single-cell animals. The very concept of the simplest finally was formulated only by the second half of the XIX century, thanks to the work of the German scientists and the scientists of Albert Kellycher and Karl Theodore Zibold.

The main characteristics and structure of the simplest

The dimensions of the simplest reach a length of 10-50 micrometers and are well considered only in an optical microscope, since indistinguishable by the naked eye of a person.

The main habitat of unicellular - water and soil, organisms occupy various positions or trophic levels food chains. The reproduction of both sexual and intimate (division of eukaryota body into two parts).

By type of food, the simplest are divided into:

• predators, they feed on algae, microscopic mushrooms and unicellular;
• those that consume food by endocytosis, for example, amcribes when swallowing is carried out by the entire cell of the microorganism;
• those who absorbs food using cells - cytostes;
• those who have an inspection type of nutrition, that is, the power is carried out without a swallowing of solid food particles due to the transportation of nutrients through the cell surface.

If we talk about the physiological structure of unicellular, then they all have two main components:

The cytoplasm of unicellular, as a rule, is represented by 2 layers:

1. etoplasm - outdoor;
2. endoplasm - internal.

Cell cytoplasm is characterized by the presence of the following cell organoids:

1. ribosomes are responsible for protein synthesis and amino acids according to genetic information in the kernel;
2. the endoplasmic network is responsible for the transport of proteins and lipids;
3. mitochondria is responsible for the oxidation of organic substances and the further use of energies released;
4. the Golgi apparatus is involved in the formation of three protein cell flows of the simplest.

Classification of simplest

Up until the beginning of the 20th century, the science considered the simplest as a whole fumigation of the kingdom of animals and their study was engaged in protozoology - the section of zoology engaged in the study of single-cell animals. Now the simplest together with algae, mushrooms and mushroom-like groups of living organisms belong to the kingdom of rubbers, mostly animal-like.

The modern classification of the animal world does not give a separate rank and a single-cell value.

Classification - Single-cell furnace (Protozoa)

• Sarcomastigophora type (Saromastigophora)
• Type of Apicplexa (Apicomplexa)
• MIXOPRIROIDI TYPE (MYXOZOA)
• Microspora type type
• Infusoria type (Ciliophora)
• Labyrinthly Type (Labirinthomorpha)
• Ascetosporah type type (Ascetospora)

Examples of simple organisms

Type of sarcomavigodors

Sarcodina (Sarcodina). Animals with a non-permanent body shape.

The body is naked, can have an outer shell or an inner skeleton.

Movement with the help of pseudopodies of different shapes.

The reproduction is intact, some and sex. These include amids, shells

amoeba, Foraminifera, Rayeviki and Sunchers.

Amoebina (Amoebina) - inhabitants of soil, fresh reservoirs, few

plasmalemm. Monoenergide and polyanener. Motion organides

lobpian. Heterotrophs. Reproduction of the useless (monotomy), Amoeba

AMOEBA Marina Mascable reproduction is a parasex process.

Shell Ameba (Testacea) - inhabitants of fresh reservoirs, soils,

mukhov on the swamps. The body is concluded in the sink of various shapes. Sink

single-chamber organic matter, some are formed

silica or the organic base includes sand. Type14.

pseudopodies - Lobopodia and Philodia. Heterotrophs. Reproduction

casual - monotomy.

Foraminifera (Foraminifera)- The inhabitants of the seas, inhabit the bottom (bentos forms), few - the thickness of the water (planktonny). The body is placed in the organic sink (more often of multi-chamber), soaked with carbon dioxide. The walls of the sink are pierced through which the rhizopodia come. Foraminifera heterotrophs. Reproduction is an alternation of sexual and non-drug processes (metagenesis).

(Volvox, for example) consists of many thousands of cells forming a hollow ball. Cells are interconnected by cytoplasmic bridges are indifferent to somatic (vegetative) and generative (parthenogonide and gametogonide), differing in structure. The size of animals and body shape is diverse.

Orgellal movement are

flagella (1, 2 or many). In some animals, the base of the flagella

continues for the ribbon, the root thread (risoplastic) is formed,

which is either attached to the core shell or lies freely. Part

zhutikioscopuses has a parabaznal body of a variety of shape, which

located near the flagella. This organoid is homologous to the device

Golges. Next to the kinetosoma can be located a kinetoplast, he

mitochondria corresponds, contains a significant amount of DNA.

Pokrov - membrane (in a few), pellicula or shell. Availability

pellicula determines the constancy of the shape of the body.

Zhgutikonostsy

mono Energies and Polynergy Animals. In vegetable

the flagendrians have a sensitive eye - stigma. By type of nutrition

AutoTrophic (Volvoks), Mixotrophs (Evglen) and heterotrophs. Can

cell mouth or animals for making production

use a plot of sticky cytoplasm. Not digestible residues

displays in the rear end of the body. Contracting vacuol of different structure.

ZHUTICONOSTSScharacteristic and sexual reproduction.

Motless reproduction in the form of monotomy and Palintomy. Paul

reproduction - kopulation. Consider the reproduction of Evglen,

tripanosomes, Volvox, false.

Evglenmultiplied with a perpetual way, by

longitudinal fission of the animal in half. First divides the kernel, then

starting from the front end of the body, and the whole body of the simplest. Farm leaving K.

one of the subsidiaries or in both subsidiaries is formed again. fifteen

Miscellaneous reproduction can occur in the cyst, reproduction

palintomy.

Tripanosoma prolonged also with a flexible division

overweight or multiple division. Part life cycle proceeds in

the human body, the other part in the body of Fly Tset. For vital

cycle Animal passes various stages, differing in structure

(Tripanosomal, leptomodnaya, critical, leishmanical shapes).

Volvoks. Propagated by sexual and sexually in gender. Paveless

reproduction - Palintomy. Parthenogonidia cells are among 4-10 divide

consistently on the surface of the maternal colony, then shifts

inside. The resulting cells are first located in the form of a plate,

then take a cupid shape and later spheroid. Output

subsidiary colonies from maternal accompanied by a breakdown of walls

the last and its death. Colony Volvoks separation and

hermaphroditic. Sex cells are formed from gametogonide. Them

little: 5-10 male and 25-30 female cells. Microgonia

multiplely divided, microgamets are formed, Macroogonia

increases in volume, macroams are formed. Sex process

oogany.

Opalins - Multi-core animals with many flagella. They are

multiply free (division in half) and sexual way

(copulation). Reproduction is associated with the change of hosts, the most

reproduction leads to the formation of a cyst. The most studied life

oPALINA RANARUM cycle. Cysts containing 3-12 nuclei are derived from

frogs during the execution period by it eggs. Tasps swallow cysts in the body

golobastikov passes Gametogonia (Games) and anisogaman

copulation. The zygota is incinerated, enters the water. Ookist, swallowing

a holotastic, develops either in a trophic form, or formed

new generation Games.

Infusoria (Ciliophora)

man and animals. For all infusories, nuclear dualism is characterized.

Heterotrophy infusoria. Divided into two classes: ciliated

(Ciliata) and sucking (Suctoria) infusories.

For ciliary infusorii

characteristic:

 Body shape diverse. More than animals prolong

oval, sand inhabitants in the form of long thin ribbons, species in

the shape of the bell, pipes, etc. Decanic infusoria

free-duty or attached to the substrate by a stem.

 The sector (cylitacy) is represented by kinets, circles, membranells and membranes. Many infusories have fixed tactile cilia.

 The Etoplasma contains Mionems and Extrums - Trichotsists.

roth hole. The structure of the oral apparatus is associated with character

food. The digestive vacuoles move in the body of the animal (cyclicosis

vacuole). Defecation is performed through a cytoprokt.

 In the endoplasm there are kernels. In the simplest case, a shower infusorium) there is one micronucleus and one macronucleus. In other representatives of several micro and macronuclei.

 The structure of the contractive vacuole and their number varies, they occupy a fixed position in the cell, open by vacuo-pose.

The reproduction of the useless - cross-division of the animal (monotomy) or Palintomy in the cyst. Sexual reproduction - conjugation. There is a temporary connection of two individuals, resorption of macronucleus in each animal, micronucleoses are divided twice (meyosis), three cores are destroyed, the fourth is divided (mitosis). The newly formed kernels - pronucleases

(stationary and migrating). There is a exchange of migratory cores. Prortleasy merge, Sinkarion is formed. Oracle is separated from each other. The conjugants reconstruct the nuclear unit. Infusoriam

it is characteristic and autogamy - the process in which the conjugation occurs in one individual.

Sucking infusorialead attached lifestyle. In adults there are no cilia. They are characterized by tentacles both unreasonable and branching. The tentacles serve to catch extraction: mining sticks to the tentacle, the pellicula of the victim dissolves and through the channel located in the tentacle, the contents of the victim flows inside

infusoria. For these infusories, nuclear dualism is also characteristic. The reproduction of the useless - kidding (formed rods with cilia) and sexual - conjugation.

Sporozoa

Spores are represented by Grenins and Cocidian-like. Everything

or the animal is infected with animals - carriers,

called transmissive. Mix three groups of transmissive

diseases: anthroponosis, anthropozonosis, zoonoses. In life cycle

endogenous and exogenous parts are isolated.

the intestines are divided into departments (2 or 3) epmeria, protocelite and datterite with one nucleus. The body of animals, inhabable cavities, gonads, spherical or dust-shaped shape. Saprofit food. Phaglylagen is postponed in the endoplasm. Reproduction is the alternation of gametogonia and sports sowing, some have also been noted by the useless reproduction

The type of simplest animals include the ancient forms of which were the progenitors of the whole diverse animal of the world. In this regard, the study of the simplest is of great importance for understanding the evolution of the animal world. The viewed type includes up to 40,000 species. The simplest are widespread on our planet and live in various environments - in the seas and oceans, fresh waters, and some species in the soil. Many simplest adapted to habitat in the body of other organisms - plants, animals, man. All of them are performed various functions: Actively involved in the cycle of substances, purify water from bacteria and rotting organic substances, affect the soil-forming processes, serve as food for larger invertebrates. Many seases are solid solid mineral skeletons. For tens of millions of years, microscopic skeletons of dead animals descended to the bottom formed there are powerful limestone deposits, chalk, green sandstone. Skeletons of some simplests are used in the practice of geological exploration to determine the oil-bearing layers.

The simplest - microscopically small animals of various shapes, the dimensions of which range from 2-3 to 50-150 μm and even up to 1-3 mm. The largest representatives of this type, such as shell roots living in the polar seas off the coast of Russia, and fossil nummulites are achieved in diameter 2-3 cm.

The body of the simplest, consists of the same components as the cell of the multicellular - the outer membrane, the cytoplasm, the nuclei and organoids, and at the same time morphologically corresponds to the same cell. Because of this simplest, often called single-cell animals (Monocytozoa). However, in saline, they cannot equate to individual multicellular cells (Metazoa), since their body performs all functions characteristic of multicellular animals. The only cell that is the body of the simplest, moves, captures food, multiplies, protects against enemies, i.e. it has all the properties of a whole body and physiologically corresponds to it. Therefore, at present, the simplest is called organisms at the cellular level or "non-tinky" organisms.

The core is a mandatory component of the body of the simplest. Usually there is one core. However, there are multi-core forms. The infusories are constantly present two cores: a large vegetative - macronucleus and small-scale generative - micronucleus. The kernel regulates the processes of life and plays an important role in the reproduction and transfer of hereditary properties to offspring.

Most of the bodies of the simplest is protoplasm. Under the microscope in it, it is possible to distinguish an outer dense, transparent, homogeneous (homogeneous) layer - the ectoplasma and located inside usually grain endoplasm with a more liquid consistency. Protoplasm is the main substrate of vital activity.

The extoplasma surface in most shapes is represented by a thin elastic shell - pellicula (lat. Pellicula - a skin) consisting of proteins and zero-like substances. Possessing the property is semi-permeable, the shell regulates the admission of substances from the outer medium (water, salt, oxygen, etc.). Pellicula is part of a live protoplasm. Some species on the surface of the body (pellicula) develop a thick shell - cuticle (lat. Cuticula - leather), which plays a protective and reference role. The cuticle does not have the properties of a live protoplasm.

In the endoplasm, in addition to the kernel, there are general applications - mitochondria, an endoplasmic network, a net apparatus, etc. In addition, in accordance with the functions inherent in the whole body, the simplest organides have organic special purposecarrying out the functions of movement, nutrition, isolation, protection, etc.

Special purpose organides

Due to nutrition, release, movement and other functions in the body of the simplest, separate sections of protoplasm are isolated, performing certain vital functions of unicellular as independent organisms. These sites received common name Organoids, or Organelle. The simplests allocate special purpose organides in accordance with the functions, unlike any other cells having general importance organs (mitochondria, centrosome, ribosomes, etc.)

Nutrition organoids Have a different structure. Depending on the type of assimilation and the method of powering the simplest are separated into several groups (Fig. 1).

The first group is autotrophic simplest. They powered like green plants, absorbing carbon dioxide, water and mineral salts from an external environment (hunching nutrition). They are equipped with chromatophores containing chlorophyll for organoids of assimilation. On the sunlight With their participation, carbohydrates are synthesized. Outotrophic simplest people do not need ready-made organic substances. They synthesize carbohydrates, fats and proteins from inorganic substances.

The second group consists of heterotrophic simplest, not halvorophyll. They can use only ready-made organic matter. Most of them feed on bacteria, algae, simplest. This method of nutrition is called Golozoy (Animal). At the same time, food is digested in special organoids - digestive vacuoles having a view of a bubble. Vacuoles are formed in protoplasm around the swallowed food particle. If there are many foods, there are several vacuoles in the body at the same time. Digestion of food occurs with the participation of digestive juices coming from protoplasm. Many simple organs have organoids that serve to enter into their body of food particles and throwing unbearable food residues to the outside. These include cell mouth - cytoste, cell pharynx - cytofarinx and anal time.

Organo selection. Most freshwater species have special pulsating vacuoles. They have the form of bubbles to which the tubuine system is suitable from the protoplasm. Pulsating vacuoles are gradually filled with liquid, after which, quickly shrinking, the fluid ejected out. In this way, the simplest are exempted from excess water, which in life under conditions of freshwater reservoir under the law of osmosis [show] All the time enters their body. If the water is not deleted, then swelling and the death of the simplest will occur.

The osmosis phenomenon consists in the following: if two solutions with different concentrations are separated by a semi-permeable membrane, then the solvent (water) moves from a solution with a smaller concentration into a solution with a greater concentration.

Motion organoids The simplest (Fig. 2) serve:

• pseudopodia or falsecakes (Greek. Pseudos - false, Podos - foot), which are temporary protoplasmic protrusions; Ameba arise at any place of her body. The movement is carried out due to the current of the protoplasm, which is gradually overflowing into one of the pseudopods; In this case, the opposite end of the body is shortened.
• flagella (or beech) - permanent organoids, having a kind of long protoplasmic threads, beginning in the front end; They produce screw-like movements.
• cilia are constant organoids, which are numerous short protoplasmic threads. Their movements consist of rapid waves in one direction and slow subsequent straightening.

Movement is closely connected with irritability and often serves as an external manifestation. An irritability is called the body's ability to respond to the impact of the outer and internal environment with certain active reactions.

The simplest possesses irritability. On the action of various mechanical, light, chemical or other irritants of the external environment, they are responding with directional movement, called Taxis (Greek. Taxis - location in order). There are taxisi, directed either towards the stimulus, or from it, and depending on the stimuli, they allocate thermo-, photo, hydro, chemo-, galvanotaxisi, etc. One of the forms of movement characteristic of taxis - amoboid movements associated with the deformation of the cell by the formation of protoplasm, in the form of pseudopodies. In the formation of pseudopodia, the Proteoplasma property is manifested to move from the state of the gel into the sol and back. Cleaning movements are carried out by flagella and cilia.

Some species for the perception of irritants there are special organoids. These include photosensitive eyes, tactless bristles, etc.

In the body of the simplest there are skeletal education. The outer skeleton is often represented by limestone or flint shells. From the inner skeletal formations should be mentioned by a special axial rod - Axostille (guest. ACSON - axis, stylos - wand).

Protection Organo. Some simplest protective devices have tricotists - short chopsticks located in the ectoplasm under Pellicula. In case of irritation, tricotists are fired, turning into a long elastic thread, affecting the enemy or prey.

Reproduction

The simplest multiplied with sexual and sexually. Miscellaneous reproduction occurs both in the form of division into two parts and in the form of multiple division (Fig. 3).

In the form of division into two parts begins with the division of the cell core. In this case, nuclear structures are uniformly distributed between two newly formed nuclei (mitosis). Following the kernel, the protoplasm is divided, after which the two newly emerged subsidiaries begin an independent life.

Most of the simplest proceeds in the form of copulation, in infusories - in the form of conjugation (Fig. 4).

When copulating (lat. Copulare - connect) two individuals fit to each other, their protoplasm and the nucleus merge, forming one individual - the zygota, which is then multiplied by anything.

Conjugation (lat. Conjagatio - pairing, copulation) - Form of sexual reproduction, characteristic of infusories. When conjugation, two infusories are applied to each other with their body. Their kernels are subjected to complex restructuring. Macronucleus of both partners are destroyed and disappeared. Micronucleases after twofold division and destruction of a part of a nuclear material form in each infusorial stationary and wandering kernel. The first remains on the spot, and the second, moving, goes into a partner, where it merges with its stationary core. The partners are then diverged, and their nuclei after division form micro and macronucleus. Conjugation is a kind of fertilization and is associated with the combination of hereditary factors (genes) of two individuals.

Insisting

If the incision of the individual falls into favorable conditions, extension occurs; An animal leaves the cyst, turns into a vegetative form and renews active life. Inciding pathogenic simplest plays an important role in the spread of protozoan diseases.

Life cycle

In the life cycle of some simplest, the alternation of morphologically different forms occurs. Different with vegetative, sex and incisive forms. The first is characterized by active nutrition and growth. Usually they breed useless. The second are represented by micro and macrogametes. Their appearance is preceded by a sexual process. Insisited forms (cysts) are characterized by stability to the action of adverse environmental conditions.

Classification

The division of the type of simplest classes is based mainly on the structure of organoids of movement and the peculiarities of reproduction. The classification is generally accepted, according to which all the simplest are divided into 4th grade.

The simplest type includes approximately 25 thousand species of single-cell animals living in water, soil or organisms of other animals and humans. Having morphological similarity in the structure of cells with multicellular organisms, the simplest differs significantly from them in a functionality.

If the cells of the multicellular animal perform special functions, the cell of the simplest is an independent organism capable of exchanging substances, irritability, movement and reproduction.

The simplest are organisms at the cellular level of the organization. In the morphological terms, the protozoa is equal to the cell, but in the physiological represents a whole independent organism. The overwhelming majority of their microscopically small sizes (from 2 to 150 microns). However, some of the now living simplest reaches reach 1cm, and the sinks of a number of fossil cornnels have in diameter up to 5-6 cm. The total number of known species exceeds 25 thousand.

The structure of the simplest is extremely varied, but they all have features characteristic of the organization and function of the cell. The general in the structure of the simplest is the two main components of the body - cytoplasm and the kernel.

Citaplasm

The cytoplasm is limited to the outer membrane, which regulates the flow of substances into the cell. In many simplest, it is complicated by additional structures that increase the thickness and mechanical strength of the outer layer. Thus, the formations of the type of pellicula and shell occur.

The cytoplasm of the simplest usually disintegrates 2 layers - outdoor lighter and tight - ektoplasma and internal, equipped with numerous inclusions - endoplasm.

In the cytoplasm localized organo organides are localized. In addition, a variety of special organelles may be present in the cytoplasm of many simplest. Various fibrillar formations are especially widespread - support and reduced fibers, contracting vacuoles, digestive vacuoles, etc.

Core

The simplest possesses a typical cellular core, one or more. The core of the simplest has a typical two-layer nuclear sheath. The kernel is distributed chromatine material and nucleists. The cores of the simplest are characterized by an exceptional morphological manifold in size, the number of nucleols, the number of nuclear juice, etc.

Features of the variety of simplest

In contrast to somatic cells, multicellular protozoa is characterized by the presence of a life cycle. It is composed of a number of steps next to each other, which in the existence of each species is repeated with a certain pattern.

Most often, the cycle begins the stage of the zygote, which corresponds to the fertilized egg cell. Behind this stage, repeated non-reproduction, carried out by cellular division, follows or repeatedly repeated. Then the sex cells are formed (gemnets), the pair merging of which again gives the zygot.

Important biological feature Many simplest is the ability to incisions. At the same time, the animals are rounded, dumped or draw the organelles of motion, isolated on its surface a dense shell and fall into the state of rest. In the incidental state, the simplest can carry sharp changes ambient, while maintaining vitality. Upon returning conversational conditions, the conditions of cysts are revealed and the simplest exit of them in the form of active, moving individuals.

According to the structure of organoids of movement and the features of reproduction, the type of simplest is divided into 6 classes. Basic 4 classes: sarcodic, flagella, disputes and infusories.

The type of simple or protigists includes unicellular animals that are not visible to the unarmed eye. The simplest type was opened only after the invention of magnifying braids, magnifiers, microscopes. Anton Levengook was the first who began to study unicellular animals. Levengook was a smart and talented man. He made important scientific discoveries when studying the type of simplest. Having improved its magnifying windows and microscopes Anton Levenguk achieved an increase in the subjects under consideration 300 times. Once he accidentally discovered a whole world of unknown people in a drop of water before the simplest invertebrate animals of the smallest dimensions.

Ameba is a large amobic organism, is the simplest microscopic animal like the simplest, which can be found in aquariums, ponds and swamps.

Infusoria is a highly organized type of simplest. Infusoria inhabit fresh reservoirs and seas, the most common type of infusories is a shoe.

Evglen green belongs to the tentance of eukaryota. This type of simplest dwells in swamps, fresh reservoirs and ditch.

All microscopic animals belonging to single-cells have a number of common features. For example, Evglen, Ameba and a shoe are animals whose body consists of one cell. Therefore, they are called unicellular. Among other animals, they have a simple structure. This speaks of a large antiquity of this type of animals. From the simplest living beings who inhabited land in the distant past, the first plants and first animals occurred in the process of further development.

Today, more than 30,000 species of single-cell microscopic animals are known.

Types of simplest

Euglifa - Lat. Euglipha, a representative of the Sarkomascular type, refers to the Corneal Class. This is a very small animal in the rumble sink.

Overnight Or Noktiluk - Lat. Noctiluca Miliaris refers to the simplest type. Nonway has the ability of glow in water. Characteristic feature Nonway, is the presence of flagellas that are organodes of movement.