Individual development of organisms is a set of biological processes that determine the growth and change in cells throughout the period of their existence. The generally accepted scientific name is ontogenesis. Its main task is to observe, identify the basic stages and features of each period, identifying patterns, as well as the analysis of changes and identifying factors that these changes can cause.

Inherent not only to person, but also to all living beings and plants. The main are:

We will not consider the individual development of the organism of plants in this short article, but we will not stop at a closer person to the development of representatives of the animal world. Stages of development, as already mentioned, people do not change and correspond to what they were listed above.

Human gametogenesis is composed of two components: spermatogenesis (ripening of men's genital cells - spermatozoa) and oogenesis (ripening of female sex cells - egg cells). Fertilization is possible only under the condition of matured genital cells in the male and female individual. If pathologies occur in fertilization, organisms can form - chimeras, some of which are quite viable.

Human embryogenesis is one of the most important stages. It is divided into the initial stage (0 - 1 week after fertilization), the proposed germing stage (2-8 weeks) and the fetal or fetal stage (9 weeks - birth). It is during this period that vital organs are formed, the body is drawn up, genetic or other pathologies can manifest themselves.

The individual development of the body in the further development of organs, increasing the size and mass, the acquisition of new mental functions, changes in motor activity and the development of its new species.

Postnatal period is the most important in the development of a new person. Its length is about 17 years (from newborn to adolescence). On the individual development of the body in this period, not only the features due to heredity, but also psychological, social factors affect. Consciousness is formed, speech, thinking and other processes by the end of this period, new individuals, as a rule, come with complete gametogenesis.

The aging of the body is the stage of fading, the depletion of all the resources of the body. Irreversible disorders in nerve cells occur, the quality of vision and hearing is reduced, "wear" vital organs, skin cover changes, the reproduction function is lost and the regeneration of tissues is slowed down.

\u003e\u003e Individual development of organisms

Individual development of organisms.

1. Where does the embryo grow mammals?
2. What is zygote?

With sexual reproduction, the beginning of the whole organism gives one cell - zygota, with a bunch of reproduction - one cell or several cells of the parent individual. But in any case, in order for the small number of cells to become a full-fledged organism, a number of complex transformations that change each other are necessary. The process of individual development of individuals from the moment of its formation until the end of the life was called ontogenesis (from Greek. Ontos is the existence and genesis - origin).

Ontogenesis is divided into two periods: embryonic (from Greek. Embion - germ) and post-empty.

The embryonic period (embryogenesis) lasts from the moment of the formation of the zygota to birth (for example, in mammals) or exit from egg shells (for example, birds). The post-embryonic period begins from the moment of birth and lasts until the end of the life of the individual.

Embryonic period.

All multicellular organisms of the embryonic development stage of the embryo are the same, but they can proceed in different ways. Eggs of some animals contain few nutrients, and the resulting zygote can develop freely. Other animals, the egg cell is equipped with huge, compared with its size, nutrient reserves, and the development of the zygote is quite different. An example of such animals are birds.

We will analyze the embryonic development of the embryo in the lancing (Fig. 48). The first stage is called crushing. fertilized Egg - zygote - begins to share mitosis. The first division occurs in the vertical plane, and the zygote is divided into two identical cells, which are called blastomers (from Greek. Blastos - germ and Meros - part).

Blastomers do not diverge, but they share again, and already 4 cells are formed. The third division occurs in a horizontal plane, and 8 blastomers are formed from four. Further, longitudinal and transverse divisions replace each other, more than more blastomers arise. Decisions occur very quickly, blastomeres do not grow, and even - as sequential divisions - decrease in size. Gradually, blastomers are located in one layer and form a hollow ball - Blastulu (Fig. 48). The cavity inside Blastula received the name of the primary body cavity or blastocel.

On one of the poles of Blastuly cells of its wall, quickly shaking mitozom, They begin to be vague inside the primary cavity of the body (Fig. 48). So the second, inner layer of the nucleus cells is formed. The resulting two-layer ball is called Gastral (from Greek. Gaster - stomach) (Fig. 48).

The outer layer of cells is called an ectoderma or an outdoor germinal sheet, and the internal - entoderma or a voltage germinal sheet. The cavity formed - inside the gastruly is the primary intestine, and the cushion leading to the primary intestine is called the primary mouth (Fig. 48). Then the third embryonic leaflet is formed between the entoderm and the mesoderm. This stage of the embryo is called neurule. At the stage of neurules the formation begins fabrics and the organs of the future animal.

The nerve plate is laid from the ectoderma (Fig. 48), which is in the future developing into the nervous tube. The vertebrate animals from the nervous tube are formed a dorsal and brain. Exteroderma also form organs of visual, olfactory and hearing systems, as well as the outer layer of the skin.

Entoderma cells form a tube - the future intestine, and the incarnation of the intestine is subsequently converted into the liver, pancreas and lungs.

Most of the animal organism is formed from the third germinal sheet - Mesoderm. It develops the cartilage and bone skeleton, kidneys, muscular, sex and cardiovascular system.
The whole organism develops from one cell - zygotes, and cells of all organs and tissues, despite the variety of buildings, contain the same set of genes.

Post-empty period.

At the time of birth or the exit of the body from egg shells, a period of post-mixed development occurs.
Post-emptilic development can be direct when. From the egg or the mother's body there is a creature similar to adults (reptiles, poultry, mammals), and indirectly when the larvae formed in the embryonic period is easier than an adult organism, and differs from it in power supply, movement, etc. (intestine, flat and ringed worms, crustaceans, insects, amphibians).

With direct development, the body's growth occurs, some organ systems are developing, such as the sexual system, etc. Thus, changes in the body are high, but the general plan of its structure and the method of existence do not change.

With an indirect development of the egg, the larva comes out: often it gives such organisms some benefits.

For example, in a low-propelled bivalve mollusk to remove the free-pointed larvae can be attached to the sinks of the sink to the body of the fish and so: transfers to new, distant habitats. Fixed ascdis larvae itself is capable of moving over long distances. As a rule, larvae and adult individuals eat differently and do not compete with each other. For example, a headastrian frog lives in water and eats vegetable food, and an adult person lives on land and is a predator.

Butterfly caterpillars eat most often with leaves, and adult butterflies - the nectar of flowers or do not eat at all. In certain types of larvae, they even have a promise to multiply independently, for example, some flat worms, amphibians. In the larch period of life, there is an intensive nutrition, an increase and settlement of animals.

Indirect post-emptilic development requires a difficult restructuring during the transition to adulthood: some organs should disappear (tips and zhabras barebody), others - arise (limbs and light frogs).

1. What starts and how does the embryonic development period ends?
2. What starts and how does the post-brand development period ends?
3. What bodies are formed from Etoderma? Entoderma? Mesoderm?
4. Give examples of animals with direct and indirect development.

Kamensky A. A., Kriksunov E. V., Book V. V. Biology Grade 9
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Individual animal development - ontogenesis - is divided into two periods: embryonic and post-empty.

Embryonic period

The embryonic period consists of several stages.

1 Ethan - Crushing and the beginning of the development of fertilized lancing eggs:

The crushing is completed by the formation of Blastuly.

2nd stage - the formation of germinal leaves, that is, the formation of a gastruul having a two-layer structure. The outer layer is Ektoderma, internal - Entoderma. Between them arises the third layer - Mesoderm. Etoderma, Entoderma and Mesoderma are called germinal sheets.

3rd stage - formation of organs:

• from ectoderma - leather, chord, nervous tube, from which the dorsal and brain and the senses are formed;
• from Entoderma - digestive channel, liver, lungs;
• mesoderma - skeleton, muscles, blood and separation systems.

During the embryonic development period, differentiation occurs in the structure and functions of cells and organs: histogenesis and organogenesis.

Histogenesis is a set of processes providing in the ontogenesis of multicellular organisms formation, existence and updating of tissues.

Organogenesis is the process of formation of primarily organs and their further differentiation.

Post-Imbrium period

Post-emptilic development can be:

• direct, in which the born descendants are similar to adult organisms (birds, mammals, man);
• indirect (with metamorphosis), when a new organism appears in the form of a larva, undergoing a number of transformations in its development (in amphibians, insects, etc.)

In post-mixed development, three phases are isolated: youth (juvenile), the phase of maturity and the phase of old age.

Embryonic development, youth phase and phase of maturity in ontogenesis have a great adaptive value and are necessary to ensure the conservation and reproduction of the form.

The life cycle is a combination of all phases of generations of a certain species. Prokaryotes and many single-celled organisms a life and cell cycle coincide. Simple and complex life cycles are known, simple cycles in plants occur without alternating generations, complicated - accompanied by alternating generations: sexual (gametophyte) and cruel (sporophyte). In animals, simple cycles are accompanied by complex transformations (metamorphosis) or alternating generations. Sophisticated cycles are accompanied by alternating the sexual and crucible, sexual and parthenogenetic, separation and hermaphroditic generations.

Development of lesson

according to general biology

on the topic "Stages of individual development of organisms"

Performed: teacherbiology Scriabin Anna Yaroslavovna

Feodosia 2016 year

Total biology lesson

Subject. "Stages of individual development of organisms"

purpose : create conditions for perception, comprehension and primary consolidation of students' knowledge about the characteristics of individual development of organisms;to give the concept of ontogenesis and consider the embryonic and post-mixed period of the development of organisms in more detail.

Educational goals : To actualize the personal meaning of students to study this topic and ensure the further development of reflexive skills of students, develop creative and analytical considerations in students.

Tasks lesson:

• characterize the content of the stages of ontogenesis: embryonic and post-mixed periods;

  expand the ideas about the posthamsbrion period of individual development, about the paths of its passage (direct and indirect);

  disclose the dependence of ontogenesis on environmental conditions.

Equipment and materials: multimedia board, computer, educational presentation, textbooks, and cards with tasks.

Basic concepts and terms: ontogenesis, embryonic period, embryo, post-brand period, crushing, Blastuly, gastula, blastomeres, Morula, Invagination, Ektoderma, Entoderma, Mesoderma, germinal sheets.

The concept of lesson : To tell about ontogenesis, turning attention to the fact that ontogenesis is extremely diverse and proceeds in different ways from different organisms, then dwells on the embryonic development of multicellular animals and show how the logging of germinal leaves occurs, prepare students to understand organogenesis processes.

Type of lesson: lesson studying new material.

Timing lesson:

Actualization of reference knowledge and motivation of training activities ...... 5 min.

Studies of a new material ...................................................... 30 min.

Generalization, systematization and control of knowledge and skills of students ... ..8 min.

Homework ................................................................................ ..2 min.

The structure and content of the lesson.

1. Actualization of reference knowledge and motivation of educational activities.

Questions to students:

1. Whatis such an individual development?

2. What is the difference between the development of plants from animal development?

3. What stages of individual development are you known in plants and animals?

4. What is the germinal and post-priest development of organisms?

5. What kind of phases is the cell cycle?

2. Studying a new material.

Plan :

The concept of ontogenesis.

Historical information.

Embryonic period.

The impact of environmental factors on the development of the embryo.

Post-empty period.

Abstract lesson.

Ontogenesis is a long and complex process of forming organisms from the moment of the formation of sex cells and fertilization (with sexual reproduction) or individual cell groups (under the milestone) until the completion of life.

(Slide - 1)

From the Greek "Ontos" - the existence and genesis - the emergence. Ontogenesis is a chain of strictly defined complex processes at all levels of the body, as a result of which the characteristics of this type of structure, vital processes, the ability to reproduce inherent in the individuals. Ends ontogenesis by processes, we are naturally leading to aging and death.

(Slide - 2)

With parents' genes, a new part receives a kind of instructions on when and what changes should occur in the body so that it can successfully go through the whole life path. Thus, ontogenesis is the implementation of hereditary information.

(viewing the educational film about ontogenesis - 9 minutes)

Historical information.

The process of the emergence and development of living organisms was interested in people for a long time, but embryology knowledge was accumulated gradually and slowly.

The genuine creator of embryology as science is Russian scientist Karl Bair (1792-1876), a native of the Estland province. He was the first to prove that in the development of all vertebrate animals, the embryo is laid first of two primary cell layers, or reservoirs. Bair saw, described, and then demonstrated at the congress of naturalists the egg cell of mammals from the dog opened. He opened a way of developing an axial skeleton in vertebrates (from the so-called spinal string-chord). Baer first found that the development of any animal is the process of deploying something preceding, or, as they would now be told, gradual differentiation of increasingly complex formations from the simpler - adventures (differentiation law). Finally, Ber first appreciated the importance of the value of embryology, as science and put it in the basis of the classification of the animal kingdom.

(Slide - 3)

Individual development of single-cell organisms.

In the simplest organisms whose body consists of one cell, ontogenesis coincides with the cell cycle, i.e. Since the appearance, by dividing the maternal cell, until the next division or death.

Outogenesis of single-cell organisms consists of two periods:

Ripening (synthesis of cellular structures, height)

Maturity (preparation for division), and the fission process itself.

Individual development of multicellular organisms.

It is much more complicated ontogenesis in multicellular organisms.

For example, in various sections of the kingdom of plants, ontogenesis is represented by complex development cycles with a change in sexual and mineralization.

In multicellular animals, ontogenesis is also a very complex process and much more interesting than that of plants.

Animals distinguish three types of ontogenesis: larval, eggland and intrauterine. The larch type of development occurs, for example, in insects, fish, amphibians. The yolk in their egg cells is not enough, and the zygota is quickly developing into a larva, which feeds independently and grows. Then, after some time, metamorphosis occurs - the conversion of the larva in an adult individual. Some species observe even a whole chain of transformations on one larvae to another and only then - in an adult part. The meaning of the existence of the larvae may be that they feed on another food than adult individuals, and thus the food base of the species is expanding. Compare, for example, caterpillage nutrition (leaves) and butterflies (nectar), or headastrics (zooplankton) and frogs (insects). In addition, in the larval stage, many species are actively populated by new territories. For example, bivalve shellfish larvae are capable of swimming, and adult individuals are almost fixed. Eggladic type of ontogenesis is observed in reptiles, birds and egg-plant mammals, the eggs of which are rich in the yolk. The germ of such species is developing inside the egg; The larch stage is absent. The inthetic type of ontogenesis is observed in most mammals, including a person. At the same time, the developing embryo is delayed in the parent organism, a temporary body is formed - a placenta, through which the mother's body provides all the needs of the growing embryo: breathing, nutrition, isolation, and other intrauterine development ends with the process of childbearing.

Embryonic period.

Individual development of multicellular organisms can be divided into two stages:

embryonic period.

post-empty period.

(Slide -4)

The embryonic or germ period of the individual development of a multicellular organism covers the processes occurring in the zygote from the moment of the first division to exit from the egg or birth.

The science examining the laws of individual development of organisms at the embryo stage is called embryology (from Greek. Embryo germ).

Embryonic development can leak two: intrauterine and end in the birth (most mammals), as well as outside the body of the mother and end with the exit of the egg shells (in birds, fish, reptiles, amphibians, iglozzy, mollusks and some mammals)

Multicellular animals have a different level of complexity of the organization; They can develop in the womb and outside the body of the mother, but in the prevailing majority of the embryonic period proceeds in a similar way and consists of three periods: crushing, gastralization and organogenesis.

(Slide - 5)

The impact of environmental factors on a developing embryo.

(Slide -6)

In a developing embryo (especially human) there are periods called critical when it is most sensitive to the damaging effects of environmental factors. This is a period of implantation by 6-7 days after fertilization, the period of placentation is the end of the second week and the period of childbirth. In these periods there is a restructuring in all body systems.

Post-empty period.

The development of the body from the moment of its birth or exit from egg shells to death is called the post-embryonic period. In different organisms, it has a different duration: from several hours (by bacteria) to 5000 years (in sequoia).

There are two main types of post-brand development: direct and indirect.

Direct development in which the body of a mother or egg shell comes out of an adult organism only with a smaller size (birds, mammals). They distinguish: non-sinic (egg-belist) type, in which the germ develops inside the egg (fish, birds), and a intrauterine type, in which the germ develops inside the mother's body - and is associated with it through the placenta (placental mammals).

With the transformation (metamorphosis), in which the larvae comes out of the egg, arranged easier than an adult animal (sometimes heavily different from it); As a rule, it has special larval organs, absent in an adult animal, and is not able to reproduce; Often the larva leads a different lifestyle than an adult animal (insects, amphibians). They are interested in the conversion of the non-healic larva of Axolotl into the ambistum, the transformation of the headastrics into frog under the influence of the thyroid hormone.

The duration of the post-brand period in different multicellular organisms is different.

For example:

Turtles - 100-150 years old,

Elephant - 77 years old

Man - 70 years old

Monkey - 35-40 years old,

Lion - 35 years old

Mouse - 3-4 years.

Generalization, systematization and control of knowledge and skills of students.

Independent work on cards with tasks.

Option 1.

What is ontogenesis?

What period of ontogenesis is called embryonic?

What is the advantage of indirect development?

(Slide - 7)

Option - 2.

What stages are allocated in the ontogenesis of all organisms?

What is the post-mixed period of ontogenesis?

What factors affect ontogenesis?

(Slide - 8)

Homework

(Slide - 9)

Remember!

What periods is the individual development of the body?

What is development with metamorphosis?

What kind of organisms is characterized by this type of development?

Individual development of individuals, the whole set of its transformations from occurred to the end of life Call ontogenesis. According to modern scientific ideas in a cell, which begins ontogenesis of individuals, a certain program for the further development of the body is laid. In the process of ontogenesis, this hereditary program is realized by the interaction of the kernel and the cytoplasm of each cell, individual cells with each other and tissues among themselves. As a result of these complex relationships based on the available genetic information and, depending on the external conditions, the specific individuality of the individual is formed.

The bacteria and single-cell eukaryotic organisms ontogenesis begins at the time of the body's formation as a result of the division of the parent cell and ends or the death of the cell, or the next division of the body, i.e., in fact, coincides with the cell cycle.

In multicellular organisms that multiply useless, ontogenesis begins with the separation of one or more cells of the parent organism, giving rise to a new individual.

In organisms breeding in sexual means, individual development begins with the moment of fertilization and education of the zygota and is divided into two periods: the embryonic (period of germs) and the post-emptil (period of post-approximal development). The ratio of the duration of these periods in organisms of different species can be very different.

Embryonic period (embryogenesis). This period lasts from the moment of the formation of the zygota before the release of the embryo from the egg or birth. It takes place in several stages (Fig. 62). In the first stage, which is called crushing The fertilized egg is divided by mitosis, resulting in 2, 4, 8, 16, etc. cells that firmly adjacent to each other. Interphase between divisions is very short, cells do not grow, so the process of crushing occurs very quickly. Ends crushing formation blastuly - Hollow ball, the wall of which consists of one layer of cells. Next, on one of the poles of Blastuly, the cells begin to divide more actively and deepen inside the spur-shaped embryo, forming a fusion. As a result of this process, a two-layer embryo is formed - gastrol. Two layers of cells forming its walls are called germinal sheets: Outdoor sheet - etoderma and internal - entoderma.

In all animals, in addition to sponges and intestinal, with the further development of the embryo between Etoderm and the Entoderma, a third embryonic leaflet is formed - mesoderma.

The further development of the embryo is associated with the interaction of three germinal leaves, of which all the tissues and organs of the body are formed. Development of nuclear organ systems - organogenesis - occurs in a certain sequence. At chordan animals, he begins with the formation of a chord and nervous system. On the spinal side of the embryo, the ectoderma cell group is separated in the form of a long plate. These cells begin to actively divide, plunging into the body of the embryo and forming the groove, the edges of which are gradually close, and then closed, forming the primary nervous tube.

Fig. 62. Crushing of the fertilized eggs of the lancing and the formation of germinal leaves

In addition to the nervous system from ectoderma, skin glands, enamel of teeth, hair, nails, skin epithelium occur. Entoderma gives the beginning of fabrics, lining the intestines and respiratory tract, forms a liver and pancreas. Muscles, cartilage and bone skeleton are formed from the mesoderm, organs of excretory, sexual and circulatory systems of the body.

In the process of embryogenesis between parts of a developing embryo, there is a close interaction: the incident of one body or system of organs determines (induces) the location and time of formation of another organ or system of organs.

The mutual influence of the parts of the embryo was demonstrated in numerous experiments. German researchers Hans Speman and Hildon Hildon took in the embryo of Triton at the earliest gastruk area of \u200b\u200bthe spinal side of the body, from which chord and mesoderma should have been developed in the future, and transplanted him on the abdominal side of another Gastrul. As a result, on the abdominal side of the second embryo from the cells, which had to give the origin of the skin, an additional nervous tube was formed. This phenomenon got a name embryonic induction.

The differentiation of the nucleus cells does not occur immediately, but at a certain stage of development. In the early stages of crushing, the nucleus cells are not yet specialized, so each of them can give rise to a whole body. If for any reason these cells are disconnected, two identical embryos are formed, containing identical genetic information, each of which develops into a full-fledged individual. As a result, one-way, or monosic twins are born. In the human population, these are the only people with identical genotype and are copies of each other.

In some animals, the embryo at an early stage of development is divided into several fragments. At the same time, each of the resulting fragments gives the beginning of a full-fledged organism. As a result, all the cubs of one generation turn out to be absolute copies of each other. This type of reproduction is characteristic of the battleship. Therefore, in the litter of the nine-day armadire, the tattoo is always an even number of one-sex young.

Post-empty period. This period begins from the moment of the birth of the body and ends with his death.

There are indirect and direct types of post-mixed development.

Indirect development. Indirect, or larger, the type of development is characteristic of many invertebrates and some vertebrate animals (fish and amphibians). This implies the birth of an individual, sometimes completely unlike an adult organism. In the process of indirect development, the individual passes through one or more lacrimal stages (the headasting of the frog, the caterpillar at the butterfly) (Fig. 63). The larvae lead an independent life, they are actively feeding, grow and develop. After a certain time, the larva turns into an adult sex - occurs metamorphosis, Therefore, sometimes this type of development is called development with metamorphosis. In metamorphosis, larch organs are destroyed and organs inherent in adult animals.

For many species, the presence of a larval stage in the development process is the possibility of resettlement and the lack of competition of various ages for habitat and food.

Direct development. This type of development is characteristic of organisms, which are born already similar to adult individuals. Just hatched duckling, a puppy born or a person's child differs from an adult smaller dimensional, somewhat other proportions of the body and underdevelopment of some organ systems, such as sexual. Direct development is eggland or intrauterine.

Fig. 63. Sequential stages of metamorphosis at the frog (bottom up): tadpoles in icons, the beginning of the metamorphosis, frog with the remains of the tail

Non-sinic or eggland Development type is characteristic of reptiles, birds, egg-adhesive mammals and a number of invertebrates. Eggs of these organisms are rich in nutrients (yolk), and the germ can develop for a long time inside the egg.

Intrauterine The type of development is characteristic of all higher mammals, including a person. All the vital functions of the embryo in this type of development are carried out by interacting with the parent organism through a special organ - placenta.

Embiric development ends in the birth process. After birth, the active growth of the body is usually observed, i.e. the increase in its size and mass. Most animals, growing, growing more slowly and, reaching a certain age, grow to grow. This type of growth is called defined. For uncertain The type of organisms growth grows all her life, such as clams, fish and amphibians. After the completion of active growth, the body enters the stage of maturity, which is associated with childbearing. The process of individual development of aging and death is ends.

Questions for repetition and task

1. What is called the individual development of the body?

2. List periods of ontogenesis.

3. What development is called embryonic, and what is the post-empty-empty?

4. What are the types of post-emptilic development of the body? Give examples.

5. What is the biological meaning of metamorphosis?

6. Tell us about germinal sheets.

7. What is cell differentiation? How is it carried out in the process of embryonic development?

8. Describe the concept of "growth". What is a certain growth? Undefined height?

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