In the lesson, we go-to-roam about how the or-ga-niz-we are-we-va-are-unicellular and multicellular, we will consider their individual development - ontogenesis, we will learn important stages in the life of multicellular organisms.
The new cell does not have enough cell structures and does not form all the proteins for its normal life-de-i-body but-sti. Therefore, the cell-to-ny cycle can be divided into several stages or phases (Fig. 2).
Figure: 2. Stages of development of a unicellular organism ()
The first stage is the stage of maturation. When the necessary cell structures are formed, the cell enters the next phase - maturity. In this phase, the cell completes all the functions it needs. Maturity for-kan-chi-va-is-Xia new de-le-ni or death of the cell.
With many-kle-to-ni-ga-niz-ma-mi si-tu-a-tion pro-ex-goes-dit is much harder. In the life of such or-ga-niz-mo, you can distinguish two important stages (Fig. 3).
Figure: 3. Ontogenesis ()
The first per-ri-ood - em-brie-o-nal-ny, in the mil-co-pi-ta-yu-shih em-bri-o-nal-nal-nal-ny-per-o-ri-o-pro-is-ho -dit inside ma-terin-sko or-ga-niz-ma (inside-uterine development). The second per-ri-od na-chi-na-et-sya with mo-men-that birth-de-nia or exit from the eggs-tse-lo-check - in-st- em-brie-o-nal-development.
Em-brie-o-nal-ny per-ri-ood includes 3 main stages:
1 fractional stage(fig. 4): pro-out-goes the division of the cell into the add-on - bla-sto-me-ry.
Figure: 4. Stage of crushing ()
In just 4 hours from one cell for-mi-ru-is-Xia 64 bla-sto-me-ra, but their growth does not come out. Za-kan-chi-va-et-sya stages of fraction-lening for-mi-ro-va-ni-em bla-stu-ly (for-ro-dy-she-vy pu-zy-rek ). It consists of one layer of cells with a lamina inside;
2 stage ha-stru-la-tion(Fig. 5) - the formation of the ro-dy-she-leaves.
In more primitive many-cell-accurate or-ha-niz-mov, for example, ki-shech-but-hollow, for-mi-ru-e - there are only two leaves: outside - ek-to-der-ma - and inside-ny - en-to-der-ma. The more you-so-ko-or-ha-ni-zo-van-zo-zo-zo-in for-mi-ru-e-xia has a third for-ro-dy-she-yi-stock - me -zo-der-ma (between ek-to-der-my and en-to-der-my).
Figure: 5. Gastrulation ()
3 stage - or-ha-no-ge-nez(Fig. 6) - this is a period of vza-and-mo-action for-ro-d-she-she-leaves, of which all the for-mi-ru-are or-ga-ny and fabrics or-ga-niz-ma.
Figure: 6. Organogenesis ()
In man, the first to isolate the head-brain, this goes out in the third week after a-part. The size of the em-bri-o-na at this moment is only 2 milli-li-meters (Fig. 7).
Figure: 7. Organogenesis, human embryo ()
Ek-to-der-ma gives na-cha-lo with skin cuts, as well as epi-te-li-al-nym fabric-yum (hair-lo-sy, zhe-le-zy external her secretions, nails), a nervous system develops from the ectoderm. Me-zo-der-ma gives na-cha-lo the main inner-nim or-ga-nam - you-de-li-tel-noy and in-lo-voy system-me. En-to-der-ma ob-ra-zu-et or-ga-ny pi-shche-va-ri-tel-noy, d-ha-tel-noy-system, as well as Threat of internal secret-reaction.
Already from the first days of its development, for-breathing or-ga-niz-ma feeling-te-len to the influence of damaging factors moat. To such factors, there are various chi-mi-ch-stuff: al-ko-gol, ni-ko-tin, le-kar-est- nye means, salts of heavy metals and nar-ko-ti-pre-para-para-you. Radiation and various infections are very dangerous for the development of a living organism.
The influence on the or-ga-nism of the mother of these factors can lead to the fact that the further development of the fetus will not pass and will come to death, or in the ro-div-she-go, the re-ben-ka will manifest because of the change, which biologists have Shy-va-yut ugliness.
After the birth-de-nia, na-stu-pa-et next-du-yu-shi-per-ri-development-development life-in-th or-ga-niz-ma - in st-um-brie -o-nal-ny (Fig. 8).
Figure: 8. Postembryonic development ()
Direct-my-development - development without interruption, with gradual growth (Fig. 9).
Figure: 9. Direct development ()
An individual is like a ro-di-tel-skiy or-ga-nizm. Direct development harak-ter-no for fish, pre-wash-out, birds and babies.
Indirect development (with me-ta-mor-pho-zom) - the process of converting the or-ga-niz-ma at the ly-chi-night stage into an adult individual (Fig. 10 ).
Figure: 10. Indirect development ()
It is co-lead-yes-it-sya ana-to-mi-che-mi and fi-zio-log-gi-che-mi pe-re-build-ka-mi or-ha- bottom-ma. This is a way of developing ha-rak-te-ren for terrestrial-water-and-on-earth.
Raz-li-cha-yut full me-ta-morphoz and incomplete met-ta-morphosis... With full me-ta-mor-pho-ze or-ga-nizm, a number of stages go through, sharply from-li-cha-yu-si from each other in a way of life and ha-rak-te-rum pi-ta-niya (fig. 11).
Figure: 11. Complete metamorphosis ()
These are the stages of an egg, li-chin-ki, ku-kol-ki, an adult individual (imago). Such a development ha-rak-ter-no for ba-bo-chek (che-shuye-wing) and beetles (stiff-winged).
With incomplete met-ta-mor-pho-ze (Fig. 12), the stages of ku-kol-ki are from-day-to-no, but if-chin-ka is not enough from an adult. This can be found at Kuz-not-chi-kov and sa-ran-chi.
Figure: 12. Incomplete metamorphosis ()
Independence-vi-si-mo- from the type of development in all living or-ga-niz-mov you-de-la-yut three stages: youth, maturity and old age ... Each of the stages ha-rak-te-ri-zu-is-Xia determined-de-len-mi-zio-lo-gi-che-mi from-me-not-no- i-mi.
Ying-di-wee-doo-al-development-development is one of the most interesting processes that go into living or-ga-niz-me, when from a single cell emerges a complex living or-ga-nizm and in the process of life-de-me tel-no-sti pre-ter-pe-va-et a number of-me-niy. Each or-ga-nizm uses its main function - to leave offspring, the life of or-ga-niz-ma za-kan-chi-va-et-sya it natural death.
Bibliography
- Mamontov S.G., Zakharov V.B., Agafonova I.B., Sonin N.I. Biology. General patterns... - Bustard, 2009.
- Ponomareva I.N., Kornilova O.A., Chernova N.M. Fundamentals of General Biology. Grade 9: Textbook for Grade 9 students of educational institutions / Ed. prof. I.N. Ponomareva. - 2nd ed., Rev. - M .: Ventana-Graf, 2005.
- Pasechnik V.V., Kamensky A.A., Kriksunov E.A. Biology. Introduction to General Biology and Ecology: Textbook for Grade 9, 3rd ed., Stereotype. - M .: Bustard, 2002.
- Blgy.ru ().
- Sbio.info ().
- Estnauki.ru ().
- What is ontogenesis and what stages does it consist of in multicellular organisms?
- What are the stages of embryonic development?
- What are the stages of development of the postembryonic period?
Lesson number ……………
Plan-synopsis on the topic "Ontogenesis. Embryonic development of the organism".
Goal:to form in students an idea of \u200b\u200bthe individual development of the body .
Tasks.Educational - to form the concepts of ontogenesis, embryogenesis, blastula, gastrula, neurula, histogenesis, organogenesis, morula, blastocoel; to acquaint with the periods of ontogenesis; to characterize the processes occurring at the stages of embryogenesis; to acquaint with the law of embryonic similarity.
Developing - continue to develop skills for working with a book, with additional scientific literature, mute tables, an interactive whiteboard; develop the ability to prepare messages, analyze textbook drawings, generalize and draw conclusions, identify patterns.
Upbringing - accurate design of diagrams in a notebook, show the negative effect of alcohol, nicotine, drugs used without a doctor's prescription on the embryo.
Equipment.Presentation “Ontogenesis. Embryonic development of the organism "
During the classes.
I. Organizational moment.
II. Knowledge update.
Today in the lesson we continue to study the topic "Reproduction and development of organisms."
Frontal poll.
Remember:
- What is called reproduction?
(The ability of an organism to reproduce its own kind).
- What breeding methods do you know?
(Asexual and Sexual).
- What is the difference between asexual and sexual reproduction?
(In asexual reproduction, one individual takes part and daughter organisms inherit identical genetic information from the mother, and during sexual reproduction, two organisms take part that produce gametes and when gametes merge, individuals with genetic information from both parents are formed).
- What is a gamete?
(Sex cell).
- What gametes do you know?
(Ovum and sperm or sperm).
- Where are they formed?
(In the gonads).
- What is called fertilization?
(The process of gamete fusion).
- What is formed as a result of fertilization?
(Zygote).
- What is a zygote?
(This is a cell with a diploid set of chromosomes, half of which are obtained from the maternal organism, and half from the paternal).
The zygote is one cell. All living organisms (fungi, plants, animals) begin their development from a zygote, that is, from one cell. What does this indicate?
(About kinship and unity of origin).
How does a whole organism develop from a zygote? From a chicken egg - a chicken, from a fish egg - a fry, from a frog egg - a tadpole, in mammals - a cub? After all, the zygote in most animals is microscopic in size, for example, in mammals 0.1 mm?
(Due to cell division and growth).
Right. The zygote undergoes a number of changes and, thanks to first cell division, then the growth and differentiation of cells, an organism is formed. Cell division - cell growth - cell differentiation is the basis of ontogenesis.
The purpose of today's lesson:
1. Get acquainted with the concept of "ontogeny".
2. Get acquainted with the types and periods of ontogenesis.
3. Learn what embryonic development is?
4. Highlight the main stages of embryonic development.
5. Establish what changes occur at each stage?
6. To establish the influence of the external environment on the development of the embryo.
Lesson plan:
1. Ontogenesis. Types and stages of ontogenesis.
2. The embryonic period and its stages.
Splitting up
- blastula
- gastrula
- neurula
- histogenesis and organogenesis
3. The influence of parts of the developing embryo.
4. The influence of the external environment on the development of the embryo.
III. Learning new material.
ONTOGENESIS.
Ontogenesis (Greek ontos - being, genesis - origin) is a process inherent in any living organism, regardless of the complexity of its organization.
Ontogenesis , or individual development, they call the entire period of life from the moment of fusion of germ cells and the formation of a zygote until the death of the organism.
The study of issues related to the individual development of organisms is engaged in embryology (from the Greek embryon - embryo).
The process of the emergence and development of living organisms has been of interest to people for a long time, but embryological knowledge has been accumulating gradually and slowly. The great Aristotle, observing the development of the chicken, suggested that the embryo is formed as a result of the mixing of fluids belonging to both parents. This opinion lasted for 200 years. In the 17th century english doctor and the biologist W. Harvey did some experiments to test Aristotle's theory. As court physician to Charles I, Harvey received permission to use the deer that live in the royal estates for experiments. Harvey studied 12 female deer that died at different times after mating. The first embryo removed from a female deer a few weeks after mating was very small and not at all like an adult animal. The deer that died at a later date had larger embryos, they had a great resemblance to small, newly born fawns.
This is how the knowledge of embryology was gradually accumulated.
Academician of the Russian Academy K.M. Baer is considered the founder of modern embryology. In 1828 he published the essay "History of the Development of Animals", in which he argued that man develops according to a single plan with all vertebrates.
In the simplest organisms, whose body consists of one cell, ontogenesis coincides with the cell cycle, i.e. from the moment of appearance, by division of the mother cell until the next division or death.
In multicellular species that reproduce asexually, ontogenesis begins with the isolation of a group of cells of the mother's body (hydra budding), which, dividing by mitosis, form a new individual with all its systems and organs.
In those species that reproduce sexually, ontogeny begins from the moment of fertilization of the egg and the formation of a zygote.
Ontogeny is not just the growth of a small individual until it turns into a large one. This is a chain of strictly defined complex processes, as a result of which the structural features, life processes, and the ability to reproduce inherent only to individuals of this species are formed. Ontogenesis ends with processes that naturally lead to aging and death.
With the genes of the parents, the new individual receives a kind of instruction about when and what changes must occur in the body so that it can successfully pass the entire life path.
TYPES OF ONTOGENESIS.
Three types of ontogenesis are distinguished in animals.
Larval (found in insects, fish, amphibians). There is little yolk in their eggs, and the zygote quickly develops into a larva that feeds on its own.
Ovipositor (observed in reptiles, birds and oviparous mammals). The eggs of these species of living organisms are rich in yolk. The embryo of these species develops inside the egg.
Intrauterine (in most mammals and humans). Wherein developing embryo is retained in the mother's body, a temporary organ is formed - the placenta, through which the mother's body provides all the needs of the growing embryo: respiration, nutrition, excretion, etc. Intrauterine development ends with the process of childbirth.
PERIODS OF ONTOGENESIS.
Any type of ontogenesis in multicellular animals should be divided into 2 periods: embryonic and postembryonic.
Embryonic period begins with fertilization and the formation of a zygote, ends with either the exit of the larva from the shell, or the exit of the individual from the egg, or the birth of the individual.
Postembryonic period begins with the end of the embryonic period. And includes: puberty, adulthood, aging and ends in death.
Today we will dwell in more detail only on the first period of ontogenesis - embryonic, or embryogenesis.
And we will consider the development of the embryo using the example of those animals whose eggs contain very little nutrients... Such animals include placental mammals, including humans.
You have sheets with a table on your tables, which you will fill out in the course of my explanation.
The main stages of embryonic development
| Main steps | Features of each stage | Schematic drawing |
| 1. Formation of a zygote | It is formed when a sperm and an egg fusion. |
|
| 2. Blastula formation | Crushing the zygote. Cell division that is not accompanied by growth. A multicellular ball is formed, consisting of 32 cells. There is a cavity inside the ball - blastocoel |
|
| 3. Formation of gastrula | Cell division at one of the blastula poles and their invagination into the blastocoel is gastrulation. Formation of two germ sheets - ectoderm and endoderm, and then the development of mesoderm. |
|
| 4. Stage of neurula | Formation of important parts of the embryo - the neural tube and notochord. The neural tube develops from the ectoderm, and the notochord from the mesoderm. |
|
| 5. Formation and formation of organs - organogenesis | Cell differentiation and organ formation. |
The development of the organism begins with a unicellular stage, which occurs from the moment of the fusion of the sperm and the egg. The nucleus formed during fertilization usually begins to divide after a few minutes, and the cytoplasm also divides with it. The resulting cells, still very different from the cells of an adult organism, are called blastomeres (from the Greek blastos - embryo, meros - part). When blastomeres are dividing, their sizes do not increase, therefore the division process is called crushing. Cleavage ends with the formation of a single-layer multicellular embryo - blastula. When cells are cleaved in all animals, the total volume of blastomeres at the blastula stage does not exceed the volume of the zygote. As a result, a multicellular ball is formed, consisting of 32 cells. There is a cavity inside the ball - the blastocoel.
In humans, on the 6th day after fertilization, blastula leaves the oviduct into the uterine cavity, and on the seventh day it is introduced into its wall. This process is called fetal implantation. After that, at one of the poles of the blastula, its cells begin to divide faster than at the other, and invade inside the blastocoel. This process was named gastrulation ... Soon, the second inner layer of the embryonic cells is formed from invagination. Such a two-layer ball is called gastrula. The outer wall of the gastrula is called the outer germ layer or ectoderm , and the inner one is the inner germ layer or endoderm. From the cells located on the border between the ecto- and endoderm, the third germ layer develops - mesoderm .
The cavity inside the gastrula is called primary gut , and the hole that leads into it - the primary mouth.
The next stage of development of the embryo after gastrula is neurula. At this stage, the formation of such important parts of the embryo as the neural tube and notochord takes place. The neural tube develops from the ectoderm, and the notochord from the mesoderm.
The final stage is an organogenesis. Thus, already at the early stages of the embryonic period of ontogenesis, tissues, organs and systems of different structures and functions develop from externally identical blastomeres. This process is called cell differentiation. Each germ layer forms its own organs and systems, for example,
| Germ leaf | Organs |
| ectoderm | Nervous system, sensory organs, skin epithelium, tooth enamel |
| endoderm | Muscle tissue, connective tissue, circulatory system, kidneys, sex glands |
| mesoderm | Epithelium of the midgut, digestive glands - liver and pancreas, epithelium of gills and lungs |
THE INFLUENCE OF ENVIRONMENTAL CONDITIONS ON EMBRYO DEVELOPMENT.
IN embryonic period the development of any organism depends on the conditions environment... Moreover, this dependence is manifested to a greater extent in placental animals. The eggs of birds, for example, are practically isolated from the environment, and the parents provide the optimum temperature for the embryo during incubation. The embryonic development of mammals is completely dependent on the mother's organism, since it receives everything it needs for life.
Intensively dividing cells of the embryo are very sensitive to adverse influences that can lead to various disorders in the developing organism. The most dangerous is exposure to chemicals that can penetrate the placenta into the embryo. In particular, such substances include nicotine, alcohol, drugs, the action of radioactivity, X-rays, poisonous substances, various medications can lead to very serious consequences - the birth of a child without arms, legs and even without a head.
When almost any link in embryonic development is violated, deviations from the normal course of development occur, i.e. anomalies.
Abnormalities can relate to the circulatory system, respiration, digestion, genitourinary system; possible non-closure of the septa between the atria, the formation of accessory spleens, doubling of the kidneys, etc.
The most dangerous for the development of the embryo are the first three months of pregnancy. During this period, the fetus is especially susceptible to viral infections, since there is no placenta yet. It forms by the end of the third month of pregnancy. For example, a disease such as rubella, which is almost safe for adults and children, can lead to the birth of a child with a heart defect, deafness, and mental retardation if the mother becomes ill with this disease at the beginning of pregnancy.
A harmful effect on the development of the embryo is exerted by the use of alcohol, drugs by its parents, and smoking tobacco. Alcohol and nicotine inhibit cellular respiration. Insufficient oxygen supply leads to the fact that fewer cells are formed in the forming organs, the organs are underdeveloped. The nervous tissue is especially sensitive to the lack of oxygen. The use of alcohol, drugs by the expectant mother, tobacco smoking, and drug abuse often lead to irreversible damage to the embryo and the subsequent birth of children with mental retardation or congenital deformities. In mild cases, disinhibition of the child is observed: lack of assembly, inability to work systematically, irrational physical activity, a low level of voluntary attention, and also very poor memory.
The embryo is very sensitive to drugs. Therefore, pregnant women should use them strictly as directed by a doctor.
No less danger to the development of the embryo is the pollution of the habitat with various chemicals or radiation ionizing radiation.
Drawing up a diagram of factors affecting the fetus in a notebook.
- And now, I'll read youan excerpt from the poem by Ali Ibn Sina "Poem of Medicine"
About children still in the womb:
As it follows, I am talking about that.
Protect the child in the womb.
Let nothing evil touch him,
Let the mother eat not as she has to,
And he eats food and drinks moisture with benefit,
So that the fetus develops normally.
Let there be little waste in food,
So that she cleans the blood at the same time.
How do you understand the lines of this poem?
Discussion of the poem.
Teacher: What is the name of the process of development of an embryo in a woman's uterus?
Pupil: This process is called pregnancy.
Teacher: You become adults. And you all already know that any sexual intercourse can result in pregnancy. Girls, girls, and even adult women are faced with the choice to keep the pregnancy or terminate it. Before you take the terrible step of murder, and this is really murder, think! Or maybe this is your last pregnancy and after an abortion, you will never have children, and you will not know the happiness of motherhood. Perhaps this child would be your support in life, would be the smartest, most talented. Indeed, for any normal person the destruction of living life is immoral, sinful. It should be noted that the responsibility for abortion is shared by two - a man and a woman.
You will now listen to Diary of the Unborn Child.
And I urge you to only one thing: think!
IV. Anchoring.
Let's summarize what was learned in the lesson.
Frontal poll or crossword puzzle.
What is ontogeny? - What types of ontogenesis do you know?
- What periods does it include?
- Embryogenesis is ……?
- What are the stages of embryogenesis?
- Briefly describe each of them? (table usage)
- List what germ layers you know and what is subsequently formed from them?
V. Homework.
§ 35, 36 "Biology" A.A. Kamensky.
Message : "Why are we getting old ...?"
MAIN STAGES OF EMBRYONIC DEVELOPMENT
| Main steps | Features of each stage | Schematic drawing |
| 1. Formation of a zygote | ||
| 2. Blastula formation | ||
| 3. Formation of gastrula | ||
| 4. Stage of neurula | ||
| 5. Bookmark and formation of organs - histogenesis |
Crossword “Ontogenesis. Embryonic development "
1. Cells formed during division of the zygote and differing from the cells of an adult organism.
2. Founder of modern embryology.
3. The first cell of a new organism.
4. The stage during which the laying and formation of organs occurs.
5. A new organism that develops from a fertilized egg.
6. Type of ontogeny characteristic of insects, fish and amphibians.
7. The stage resulting in the formation of important parts of the embryo.
8. The cavity inside the ball formed by blastomeres.
9. The period of ontogenesis, which begins with fertilization and ends with the emergence of a new individual.
10. A temporary organ in the maternal organism, which provides the embryo with respiration, nutrition, excretion, etc.
During the classes
1. Organizational moment.
2. Checking d / z:
a) define the words: mitosis, meiosis, gametes, zygote, gametogenesis, ovogenesis, spermatogenesis;
b) students' story about asexual reproduction;
c) students' story about sexual reproduction.
3. Communication of the topic and purpose of the lesson: "Individual development of the organism."
Teacher's word:
So, during sexual reproduction, the beginning of the whole organism is given by one cell - the zygote, with asexual reproduction - one or more cells of the parent individual.
But in any case, in order for a small number of cells to turn into a full-fledged organism, a whole series of complex, replacing transformations is necessary.
4. Work on new material.
Ontogenesis (individual development of an organism) is the period of development of an organism from the birth and formation of a zygote to the end of an individual's life.
Ontogenesis is divided into 2 periods: embryonic and postembryonic development.
5. Embryonic development (embryogenesis, for example, lancelet).
Embryogenesis is the development of an organism from the moment the zygote is formed until birth or release from the egg membranes.
Embryogenesis stages:
a) Blastula (cleavage) - during which the zygote divides by mitosis, and the cells formed during cleavage are smaller than the zygote.
Crushing ends with the formation of a blastula - a hollow ball or bubble; blastula cells - blastomeres (located on the surface).
The cavity of the blastula is called the blastocoel, and the formation of a single-layer embryo is called blastulation.
b) Gastrula (gastrula) - the formation of a two-layer embryo, and a two-layer ball - gastrula.
The outer layer of cells (or germ layer) is called the endoderm.
The cavity inside the gastrula is the primary intestine, and the opening leading to the primary intestine is the primary mouth (they are formed by invagination or movement of cells).
c) Neirula - the formation of the third germ layer - the mesoderm. The peculiarity of this stage is that the formation of tissues and organs of the future organism begins (organogenesis).
Derivatives of germ layers.
6. Postembryonic development.
This development of the organism from the moment of birth and lasts until the end of the individual's life (emergence from the egg membranes).
Postembryonic development is divided into 3 periods:
1. Pre-productive - body growth, development and puberty.
2. Reproductive - active functioning of an adult organism, reproduction.
3. Post-reproductive - aging, gradual extinction of vital processes.
Development types:
a) direct,
b) indirect (with metamorphosis):
1) complete transformation (in addition to the larval stage, there is a pupa stage - butterflies, beetles),
2) incomplete transformation (there is a larva, but no pupa - grasshoppers, tadpoles).
7. Biogenetic law (comparison of embryos).
K. Baer formulated the law of embryonic similarity: "Within a type, embryos, starting from the earliest stages, exhibit a certain general similarity."
Müller and Haeckel formed a biogenetic law: "Ontogeny is a brief repetition of phylogeny."
The value of the biogenetic law is that it testifies to the common ancestors of animals belonging to different systematic groups.
8. "The story of the unborn child. Abortion".
Fragment of the film: "Development of the human embryo by week" (discussion of the act of a failed mother and the harm of abortion).
9. Let's compete (fixing).
10. Summing up.
Questions.
1) How does the embryonic period of development begin and how does it end?
2) How does the postembryonic period of development begin and how does it end?
3) What organ systems are formed from the ectoderm? endoderm? mesoderm?
4) Give examples of animals with direct and indirect development.
5) What is the significance of the biogenetic law?
I .. Form of organization learning activities... Lesson plan: 1.Orgmoment. II. Check of knowledge. Frontal work (answers to teacher's questions) III. Learning new material. 1. Brief history reference... About the contribution of scientists to the development of embryology 2. Periods of ontogenesis: -Embryonic (from the formation of the zygote to birth or exit from the egg membranes) -Posttembryonic period (from the exit from the egg membranes, or birth to death). 2.1. The embryonic period of development in animals: 1st stage - crushing, 2nd - gastrula, 3rd - neurula (using the table "Individual development of the lancelet) 2.2. Independent work of students according to the textbook of A.A. Kamensky (p. 134) and textbook VB Zakharov Fig. 7.3., work on the Interactive board. Sign the picture "Embryonic leaves", as well as filling out the table "Differentiation of cells." 3. Interaction of parts of the embryo. Embryonic induction (student message). 4. Influence of environmental conditions environment on the development of the embryo (student's message) Teacher's commentary on slides 5. Information about newborns in the Tselinny district of the Republic of Kazakhstan (teacher's commentary) 6. Students work with terms, filling out a dictionary of terms 7. Reinforcement and conclusions. II. Types of educational activities of students in the lesson: A). collection of information in various sources (textbooks, Internet), work on the Interactive board for drawing up tables, diagrams; B). comprehension of the scientific content of the leading concepts (embryology, embryogenesis, ontogenesis, blastula a, gastrula, organogenesis, neurula, embryonic induction, ectoderm, mesoderm, endoderm); C) study of the effect of unfavorable environmental factors on the developing embryo, diseases caused by one reason or another; D) determination of the basic rules for maintaining and improving health and the environment. III. Description of the organization of creative activity of students. In the course of work in the lesson, the students worked on the Interactive board: they signed the diagram "Types of ntogenesis", the drawing "Embryonic leaves", filled out the table "Differentiation of cells", the performance of students with messages "Embryonic induction", "On the harmful influence of environmental factors on development embryo ". IV. Materials for methodological support this lesson.: Portraits of scientists: K. Beer, II Mechnikov, A. Kovalevsky, E. Haeckel, F. Muller, A. Severtsov; Table on General Biology "Individual development of the lancelet"; Lesson presentation; Quest cards; children's rubber ball; textbook General biology 10-11 grades, A.A. Kamensky, E.A. Kriksunov, V.V. Pasechnik; Textbook General Biology Grade 10 profile level, Zakharov V.B., Mamontov S.G., Sonin N.I., Zakharova E.T .; information about newborns in the Tselinny district of the Republic of Kazakhstan (table)
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Ministry of Education, Culture and Science of the Republic of Kalmykia
MOBU "Troitskaya average comprehensive school them. G.K. Zhukov "
Competition "My Best Lesson"
Direction: Natural - scientific
“Ontogenesis is an individual development of an organism. Embryonic period "
(biology lesson in grade 10 "A")
Developer: Arsenova Yulia Bembeevna
Position : biology teacher
OU address : 359180, Republic of Kalmykia,
Virgin area, with. Troitskoe,
st. Chavychalova 11A
OU phone: 8 (847-42) 9-12-56
Virgin area, with. Troitskoe,
st. P. Akuginova, 14, apt. 7
village Troitskoe, 2013
Lesson plan: I. Organizational moment.
II. Knowledge update... Today in the lesson we continue to study the topic "Reproduction and development of organisms."
Frontal poll. Remember: What is called reproduction?
Oveet: The ability of an organism to reproduce its own kind.
What breeding methods do you know? Student answer:Asexual and sexual.
What is the difference between asexual and sexual reproduction?
Student responses : In asexual reproduction, one individual takes part and daughter organisms inherit identical genetic information from the mother, and in sexual reproduction, two organisms take part that produce gametes and when gametes merge, individuals with genetic information from both parents are formed.
What is a gamete? Answer:The reproductive cell. What gametes do you know? Answer:Ovum and sperm or sperm.
Where are they formed? Answer:In the sex glands.
What is fertilization? Answer:The process of gamete fusion.
What is the biological significance of fertilization? Answer:Restoration of the diploid set of chromosomes.
What is formed as a result of fertilization? Answer:Zygote
What is a zygote? Answer:This is a cell with a diploid set of chromosomes, half of which are obtained from the maternal organism, and half from the paternal
Teacher ... The zygote is one cell. All living organisms (fungi, plants, animals) begin their development from a zygote, that is, from one cell. What does this indicate? Answer:About kinship and unity of origin. How does a whole organism develop from a zygote? (Due to cell division and growth).
Right ... The zygote undergoes a number of changes and, thanks to first cell division, then the growth and differentiation of cells, an organism is formed. Cell division - cell growth - cell differentiation is the basis of ontogenesis.
Questions to the class:
* What is ontogeny? * What is the difference between ontogeny in unicellular organisms and ontogenesis in multicellular organisms? * What types of ontogenesis are distinguished in animals? List the features.
* How does the embryonic period of embryogenesis in a crocodile end? * What are the functions of the placenta?
Guys, let's remember the types of ontogenesis. Pay attention to the ID (interactive whiteboard), where the diagram is "Types of ontogeny". You need to fill in the missing titles.
Work at the ID. The student writes down three types of ontogenesis on the diagram: larval, ovipositor and intrauterine and give brief description, other students work with the table "Types of ontogeny" (Attachment 1.)
The purpose of the lesson : to study the process of ontogenesis, periods of ontogenesis (embryogenesis in detail), the stages of ontogenesis and the processes occurring at these stages, get acquainted with the phenomenon of embryonic induction and the influence of the external environment on the development of the embryo (embryo).
Tasks: Educational- to form the concepts: ontogeny, embryogenesis, blastula, gastrula, neurula, histogenesis, organogenesis, morula, blastocoel; to acquaint with the periods of ontogenesis; to characterize the processes occurring at the stages of embryogenesis; to acquaint with the law of embryonic similarity.
Developing - continue to develop skills in working with a book, with additional scientific literature, mute tables, an interactive whiteboard; develop the ability to prepare messages, analyze textbook drawings, generalize and draw conclusions, identify patterns.
Upbringing - neat design of diagrams in a notebook; show the negative effect of alcohol, nicotine, drugs used without a doctor's prescription on the embryo.
Equipment : multimedia presentation, interactive whiteboard, table "Ontogenesis in animals", cards with tasks and tests, portraits of scientists - K.M.Ber, I.I.Mechnikov, A.O. Kovalevsky, A.N.Severtsov, E. Haeckel and F.Müller.
. ... The study of issues related to the individual development of organisms is engaged inembryology (from the Greek embryon - embryo). Academician is rightfully considered the founder of modern embryology Russian academy K.M.Bair. In 1828, he published the essay "The History of the Development of Animals", in which, on the basis of fundamental observations of the development of the chicken embryo and the embryos of mammals, he laid the foundation for the theory of germ layers and formulated the law of embryonic similarity. K.M.Bair proved that man develops according to a single plan with all vertebrates. Science owes modern ideas about germ layers to A.O. Kovalevsky, who discovered ectoderm, endoderm and mesoderm in all groups of chordates. The thoughts of Charles Darwin, the works of K. Baer, \u200b\u200bA.O. Kovalevsky, I.I. Mechnikov and other embryological scientists paved the way for the creation by German scientists F. Müller and E. Haeckelbiogenetic law, Wherebyontogenesis, those. individual development of the species, there is a brief repetitionphylogenesis - the historical development of the species to which it belongs. A great contribution to the development of biogenetic law was made by the Russian scientist-academician A.N.Severtsov. He found that in the individual development of animals, the traits are repeated not of adult ancestors, but of their embryos.
Ontogenesis periods: 1.Embryonic 2. Postembryonic Embryonic development in animals:
1st stage - crushing, a few hours after the formation of the zygote, formed as a result of fertilization, begins immediately in the oviduct. The first division occurs in the vertical plane, and two identical cells are formed - blastomeres. They do not diverge, but divide again, as a result of which 4 blastomeres are formed. Then they are divided, but in a horizontal plane. The division of blastomeres quickly follows one after the other, and they do not have time to grow. Therefore, in the initial stages of cleavage, a lump of blastomeres, which is calledmorula, does not exceed the zygote in size. At 32 blastomeres, a hollow ball with walls in one row of cells forms -blastula ... The cavity inside the blastulablastocoel. Teacher question: How do cells divide?Answer (Mitosis).
Mitotic division of the zygote and blastomeres is not accompanied by the growth of the formed daughter cells to the volume of the maternal one, and the size of the blastomeres as a result of successive divisions progressively decreases. In all animals, the size of the blastula does not differ from the zygote, that is, the cells are the same in size.
Teacher: Why are cells small in size?Answers: ( No growth occurs).
For crushing, other features are characteristic of all species of animals. For example, all cells in a blastula have a diploid set of chromosomes, are identical in structure and differ from each other mainly in the amount of protein they contain. Is not
specialized cells. Another feature of cleavage is the extremely short mitotic cycle of blastomeres in comparison with the cells of an adult organism. During a very short interphase, only DNA doubling occurs. Another very important feature of cleavage is that the cytoplasm of the zygote does not move during division. The crushing process ends with the implantation of the embryo into the uterine cavity. (work according to the table and figure 55 p. 132 of the textbook, authors: Kamensky A.A., Kriksunov E.A., Pasechnik V.V. and the textbook, authors: Zakharova V.B., Mamontova S.G., Sonina N .I. And Zakharova E.T. - profile level Fig. 7.1., P. 219.)
2nd stage - Gastrulation begins when the number of blastula cells reaches several hundred or thousands. (the formation of the second germ layer -endoderm.)
A rough model of the gastrulation process can be the experience with a punctured children's ball.Children's two-color rubber balls are separated by a stripe along the equator. If the ball is folded in such a way that a cap or bowl is formed, the edge of which will be a strip, then you get a simplified model of the gastrula of the lancelet. In this case, the role of the ectoderm will be played by the surface painted with one color, and the role of the endoderm by the surface with another color. The cavity inside the blastula is the primary intestine, the opening that leads into it is the primary mouth. From the cells lying between the ecto- and endoderm is formedmesoderm, except for coelenterates and sponges. Due to the appearance of the mesoderm, the embryo becomes three-layer. The cavity inside the gastrula is called the primary gut, and the opening that leads into it is called the primary mouth.
An anus is formed at the site of the primary mouth, and a secondary (real) mouth is formed at the opposite pole of the embryo. Therefore, mammals (like all chordates) are classified as deuterostomes. The essence of the gastrulation process is the movement of cell masses. The cells of the embryo practically do not divide and do not grow. However, at this stage, the use of genetic information cells of the embryo, the first signs of differentiation appear.
3rd stage - Neyrula (primary organogenesis: the neural tube, notochord, intestinal tube are formed). When a neural tube is formed, part of the ectoderm cells first forms a plate, then a groove on the dorsal side of the embryo. The edges of this groove are closed, and a neural tube is formed, which lies under the ectoderm. Later, at the front end of the neural tube, the brain is formed, at the back - the spinal cord. The rest of the ectoderm is the rudiment of the skin epithelium. The dorsal part of the endoderm is under the nerve rudiment, separates from the rest of the endoderm and folds into a dense cord - notochord. From the rest of the endoderm, the mesoderm and intestinal epithelium develop. Further differentiation of the embryonic cells leads to the emergence of numerous derivatives of the germ layers - organs and tissues. Thus, already at the early stages of embryonic development of ontogenesis, tissues, organs, and organ systems of various structures and functions develop from externally identical blastomeres.
This process was namedcell differentiation... It is due to the fact that different strictly defined groups of genes are activated in different cells of the embryo. This leads to differences in the chemical reactions that take place in them, and in the structure of the structures that make up the blastomeres. From a morphological point of view, differentiation is expressed in the fact that several hundred types of cells of a specific structure, differing from each other, are formed. From a biochemical point of view, the specialization of cells consists in the synthesis of certain proteins that are characteristic only of this type of cells. In the skin, in epithelial cells, keratin is synthesized, in erythrocytes - hemoglobin, in the cells of the insular tissue of the pancreas - insulin, etc. With further differentiation of the cells that make up the germ layers, organs are formed. Students' independent work according to the textbook Kamensky A.A. (p. 134), work on ID (interactive whiteboard). Subscribedrawing "Germ leaves", and also filling the table"Cell differentiation" (see Appendix 2)The interaction of parts of the embryoEmbryonic induction.
Teacher ... How, then, do cells of different tissues in organisms turn out to be different in structure and function, i.e., differentiate? After all, they are all formed from a zygote, by division and have the same set of chromosomes. The special properties of tissues are determined by proteins. The specificity of the cells of organ rudiments does not appear immediately, but only at the stage of gastrula and neurula.Student message. (see Appendix 3)
- The influence of environmental conditions on the development of the embryo.
Teacher ... The developing embryo is influenced by the environment. In the embryonic period, the development of any organism depends on environmental conditions. To a greater extent, this dependence is manifested in invertebrates. The eggs of birds are practically isolated from the environment, and the parents provide the optimum temperature for the embryo during incubation. In placental mammals, the mother's organism is the mediator between the embryo and the environment, from which the embryo receives nutrition, oxygen, and heat. Student message “The influence of environmental conditions on the development of the embryo "(cm ... Appendix 4) Teacher.Information about newborns in the Tselinny district of the Republic of Kalmykia (see Appendix 5)Analysis of the table
5. Student work, filling out the vocabulary biological terms (see Appendix 6)
Anchoring. Let's discuss: 1. What is the embryonic development of an organism? 2. Name the stages of embryonic development in multicellular animals. 3. How does the zygote split? 4. How is cleavage different from mitotic cell division in adult animals? 5. How is a two-layer embryo formed? 6. What germ layers are formed during embryogenesis?Conclusions: 1. Academician of the Russian Academy K.M.Ber is rightfully considered the founder of modern embryology.2. The merit of the creation of evolutionary embryology belongs to the remarkable Russian scientists AO Kovalevsky, II Mechnikov.3. From the moment of the formation of the zygote and until the emergence of the egg membranes or birth, the embryonic continues, i.e. embryonic period.4. In the embryonic period, there is an increase in the number of cells, and then their differentiation.5. Specialization of embryonic cells leads to the emergence of the first tissues and organs.6. In the process of embryonic development, the tissues of the embryo influence each other - embryonic induction.7.Uncontrolled use of certain drugs, alcohol, drugs, nicotine, sulfur dioxide and carbon inhibit the penetration of oxygen to the tissues. Homework: § 36.37 (study A.A. Kamensky), §7.1-7.2.3. (teacher VB Zakharov) fill in the table "Dictionary of biological terms" using the "Brief Dictionary of Biological Terms" by F. Reimers
APPENDIX
1. Form of organization of educational activities:
Lesson plan:
I. Organizational moment
II. Check of knowledge. Frontal work (answers to teacher's questions)
III. Learning new material.
1. Brief historical background... The contribution of scientists to the development of embryology (teacher's story)
2 .. Periods of ontogenesis:
Embryonic (from the formation of a zygote to birth or exit from the egg membranes)
Postembryonic (from release from egg membranes or birth to death)
2.1. The embryonic period of development in animals:
1st stage - crushing, 2nd stage - gastrula, 3rd stage - neurula (explanations of the teacher using the table "Individual development of the lancelet"
2.2. Independent work of students according to the textbook of A.A. Kamensky. (p. 134) and the textbook of V.B. Zakharov. Figure 7.3,work on an interactive whiteboard.Sign drawing "Germ leaves"and also filling the table"Cell differentiation"
3. Interaction of parts of the embryo. Embryonic induction. (student message)
4. The influence of environmental conditions on the development of the embryo, hearing the student's message (teacher's comment on slides)
5. Information about newborns in the Tselinny district of the Republic of Kalmykia
(teacher's comment on the table)
6. Work of students with terms, filling out a dictionary of biological terms.
7. Anchoring and conclusions
II. Types of educational activities of students in the lesson:
A) Collecting information in literary sources, on the Internet, work on an interactive board for drawing up tables, diagrams;
B) Comprehension of the scientific content of the leading concepts (embryology, embryogenesis, ontogenesis, blastula, gastrula, organogenesis, neurula, embryonic induction, ectoderm, mesoderm, endoderm);
C) Study of the effect of unfavorable environmental factors on the developing embryo, diseases caused by one reason or another.
D) Determination of the basic rules for maintaining and improving health and habitat.
III. Description of the organization of creative activities of students
In the course of work in the lesson, the students worked on an interactive board: they signed the scheme "Types of ontogenesis" - larval, ovipositor, intrauterine, drawing "Embryonic leaves", filling out the table "Differentiation of cells", students' speeches with messages "Embryonic induction", "On the harmful effect environmental factors on the development of the embryo "
V. Materials for the methodological support of this lesson
* Portraits of scientists:K. Baer, \u200b\u200bI. I. Mechnikov, A. O. Kovalevsky, E. Haeckel, F. Müller, A. N. Severtsov
* Table on general biology "Individual development of the lancelet"
* Slides for the lesson, for working on an interactive whiteboard;
* Cards with tasks: "Differentiation of cells", "Basic terms on the topic of the lesson";
* Children's rubber ball
* Textbook General biology grades 10-11, A.A. Kamensky, E.A. Kriksunov, V.V. Pasechnik
* Textbook General Biology Grade 10 profile level, Zakharov V.B., Mamontov S.G.,
Sonin N.I., Zakharova E.T.
* "Information about newborns in the Tselinny district" - table
Attachment 1.
TABLE 1. TYPES OF ONTOGENESIS
Options | Larval | Oviparous | Intrauterine |
The amount of yolk in the egg | Little yolk | A lot of yolk | Very little yolk |
Who | Insects, fish, amphibians | Reptiles, | Most |
Stage presence | there is | No | No |
Where is developing | In the external environment | Inside the egg | In maternal |
Appendix 2.
Cell differentiation table
Slide captions:
Biology lesson in grade 10 Arsenova Yulia Bembeevna - teacher of biology, MOBU "Troitsk secondary school named after G.K. Zhukov", Republic of Kalmykia, 2013.
The topic of the lesson is “Ontogenesis - the individual development of an organism. Embryonic period "
The purpose of the lesson: to study the process of ontogenesis, periods of ontogenesis (embryogenesis in detail), the stages of ontogeny and the processes occurring at these stages, to get acquainted with the phenomenon of embryonic induction and the influence of the external environment on the development of the embryo
Tasks: Educational:. to form the concepts: ontogenesis, embryogenesis, blastula, gastrula, neurula, histogenesis, organogenesis, morula, blastocoel; to acquaint with the periods of ontogenesis; to characterize the processes occurring at the stages of embryogenesis; to acquaint with the law of embryonic similarity. Developing: continue the formation of skills for working with a book, with additional scientific literature, mute tables, an interactive whiteboard; develop the ability to prepare messages, analyze textbook drawings, generalize and draw conclusions, and identify patterns. Educational: neat design of diagrams in a notebook; show on the slides what the negative effect of alcohol, nicotine, drugs used without a doctor's prescription on the embryo, contributing to the formation of the need for a healthy lifestyle.
Lesson type - Lesson in studying new material Form of the lesson - - lecture with elements of conversation; - independent work students on an interactive whiteboard - filling in diagrams, tables; -Speech of students with messages
Multimedia projector; -interactive board; - a computer; - presentation; - Handout; portraits of scientists: * K.M.Ber, I.I. Mechnikov, A.O. Kovalevsky, A.N.Severtsov, E. Haeckel, F.Müller. * Table on general biology "Individual development of the lancelet" * Slides for the lesson, for work on the interactive board; * Cards with tasks: "Differentiation of cells", "Basic terms on the topic of the lesson"; * Children's rubber ball * Textbook General biology 10-11 grades, A.A. Kamensky, E.A. Kriksunov, V.V. Pasechnik * Textbook General biology 10th grade profile level, Zakharov.V.B., Mamontov S.G ., Sonin N.I., Zakharova E.T. * "Information about newborns in the Tselinny district of the RK" - table LESSON EQUIPMENT:
Stages of the lesson I. Organizational moment II. Check of knowledge. Frontal work (answers to teacher's questions) III. Learning new material. 1. Brief historical background. About the contribution of scientists to the development of embryology (teacher's story) 2. Periods of ontogenesis: Embryonic (from the formation of the zygote to birth or exit from the ovum) Postembryonic (from the exit from the egg membranes or birth to death) 2.1. The embryonic period of development in animals: 1 stage - crushing, stage 2 - gastrula, stage 3 - neurula (explanations of the teacher using the table "Individual development of the lancelet", answers to the teacher's questions) 2.2. Independent work of students according to the textbook of Kamensky A.A. (p. 134) and the textbook of VB Zakharov. See Figure 7.3, working on the interactive whiteboard. Sign the drawing "Embryonic leaves", as well as filling in the table "Differentiation of cells" 3. Interaction of parts of the embryo. Embryonic induction. (Student's message) 4. The influence of environmental conditions on the development of the embryo, listening to the student's message (teacher's commentary on slides) 5. Information about newborns in the Tselinny district of the Republic of Kalmykia (teacher's commentary on the table) 6. Students work with terms, filling out dictionary of biological terms. 7. Reinforcement and conclusions Reflection
Methods: comparison; conversation; generalization; connection with life; interdisciplinary communication.
Types of work Independent work Answers to questions Messages from students conversation work with a table Work on an interactive whiteboard reflection
Technologies: 1) ICT ( information and communication); 2) Personality-oriented; 3) Group; 4) Health-saving.
Elements of health-saving technologies - optimal lesson density - respectful communication style; - rational alternation of types of educational activities; - correct working posture;
Types of educational activities of students in the classroom: A) Collecting information in literary sources, on the Internet, work on an interactive board for drawing up tables, diagrams; B) Comprehension of the scientific content of the leading concepts (embryology, embryogenesis, ontogenesis, blastula, gastrula, organogenesis, neurula, embryonic induction, ectoderm, mesoderm, endoderm); C) Study of the effect of unfavorable environmental factors on the developing embryo, diseases caused by one reason or another. D) Determination of the basic rules for maintaining and improving health and habitat.
Description of the organization of the creative activity of students In the course of work in the lesson, students worked on an interactive board: they signed the scheme "Types of ontogenesis" - larval, ovipositor, intrauterine, drawing "Embryonic leaves", made schematic drawings in notebooks of stages of embryonic development, filled in the table "Differentiation of cells" , made reports: "Embryonic induction", "On the harmful influence of environmental factors on the development of the embryo"
Expected results: Students should define the key concept - ontogenesis, name the preconditions of the biogenetic law, describe the periods of ontogenesis, characterize the contribution of Russian scientists to the development of embryology, compare the stages of the zygote and blastula, explain the biological significance of cleavage, highlight the features of cleavage in comparison with mitosis, characterize the process crushing, explain the mechanism of gastrulation and organogenesis, explain the mechanism of organogenesis, prove the manifestation of embryonic induction, prove the unity of the origin of the animal world, take good care of your health
“To be well-born is the right of every person,” LN said. Tolstoy. You are on the verge of an independent life. And we would very much like your life path not to be overshadowed by troubles. After all, a lot depends on you. Be healthy and happy! This is your homework for life! Conclusion
Reflection Students have a comprehension and self-assessment of knowledge Read fragments of paragraphs 36 and 7.1-7.2.3. using "Read With Marks": + - know V - learned new? - causes difficulty! - I want to know
thanks for attention!!!