The individual development of the organism is briefly outlined. Summary of the lesson "individual development of the organism" - synopsis of biology lessons - file directory - biology is not for nerds
INDIVIDUAL DEVELOPMENT OF ORGANISMS. BIOGENETIC LAW
Tasks : to form knowledge about the essence of ontogenesis and its stages; to show the influence of environmental factors on ontogenesis, to study the main patterns and stages of the embryonic and postembryonic period of development; to reveal the general patterns of development by the example of comparing the embryos of chordates, to trace the law of embryonic similarity, the biogenetic law.
Content elements: ontogenesis, embryogenesis, cleavage, blastula, gastrula, ectoderm, endoderm, mesoderm, gastrulation, neurula, postembryonic development, the law of embryonic similarity, biogenetic law.
Lesson type: combined.
Equipment: tables "Individual development", "Similarity of embryos of vertebrates", presentation.
During the classes
I. Organizing time.
II. Testing students' knowledge.
The task. Complete the table using the answer choices below.
Comparison item
Answer options:
a) one
b) fast
c) meiosis is absent
e) no germ cells
f) there is meiosis
i) plants and animals
l) two
m) slowly
Answer:
Reproduction
III. Learning new material.
1. Ontogenesis - the process of individual development of an organism (from conception to death), as a result of which its hereditary information is realized.
Ontogenesis consists of two periods:
1) Embryonic – begins from the moment of fertilization and continues until the birth of the organism.
2) Postembryonic – begins immediately after birth, when the organism is able to exist independently, and continues until death.
2. The embryonic period of development.
1) When the germ cells shine,zygote .
2) The zygote begins to split intoblastomeres until it formsblastula (a hollow spherical structure with one layer of cells - a single-layer embryo).
3) Gastrulation - the formation of a bowl-shaped two-layer embryo occurs by invagination (cell migration, stratification or fouling) of one of the blastula walls. Two-layered embryo, consisting of two germ layers (ectoderm (outdoor) andendoderm (internal)) is calledgastrula ... Between two germ layers, a third germ layer can be laid -mesoderm .
4) In each of the germ layers, the axial structures of the embryo (chord, neural tube, digestive tube) are laid. This stage of the embryo is calledneurula .
5) Histogenesis and organogenesis - there is further differentiation of tissues, the formation and development of organs, organ systems.
The task... Using the text of the textbook (§ 3.4), fill in the table.
Germ leaflets, their derivatives
Leaflet title
Remember!
3. Postembryonic development of the organism consists of three periods:
1) Pre-productive - body growth, development and puberty.
2) Reproductive - active functioning of the adult organism, reproduction.
3) Post-reproductive - aging, gradual extinction of vital processes.
Postembryonic development animals are of two types - direct and indirect.
Postembryonic development of animals
4. Consider the "Embryonic Similarity in Vertebrates" chart.
If we compare the embryos of various vertebrates, it can be noted that in the early stages of development, their embryos are very similar, but with further development, the differences become more, since signs of a class, genus, species, individual organism are acquired. This example proves the relationship between the individual development of each organism and the evolution of the species to which this organism belongs.
This relationship is reflected in the biogenetic law formulated by F. Müller and E. Haeckel:The individual development of an individual (ontogeny) to a certain extent repeats the historical development of the species (phylogeny) to which this individual belongs.
That is, the biogenetic law says that ontogeny is a brief repetition of phylogenesis in a naturally altered and abbreviated form. A. N. Severtsov established that in ontogeny the traits are repeated not of adult individuals of ancestors, but of their embryos.
IV. Consolidation of the studied material.
Conversation on questions:
1. What is ontogeny?
2. What periods is ontogeny divided into? Describe each of the periods.
3. What changes occur with the zygote in the embryonic period?
4. What is the meaning of the biogenetic law?
Homework: § 3.4 (repeat § 2.14, § 3.1–3.3).
Comparison of sexual and asexual reproduction
Comparison item
Answer options:
a) one
b) fast
c) meiosis is absent
d) offspring differ from their parents at the genetic level
e) no germ cells
f) there is meiosis
g) descendants are identical to parents
h) female and male sex cells
i) plants and animals
j) plants, microorganisms, lower animals
l) two
m) slowly
Comparison of sexual and asexual reproduction
Comparison item
Answer options:
a) one
b) fast
c) meiosis is absent
d) offspring differ from their parents at the genetic level
e) no germ cells
f) there is meiosis
g) descendants are identical to parents
h) female and male sex cells
i) plants and animals
j) plants, microorganisms, lower animals
l) two
m) slowly
Comparison of sexual and asexual reproduction
Comparison item
Answer options:
a) one
b) fast
c) meiosis is absent
d) offspring differ from their parents at the genetic level
e) no germ cells
f) there is meiosis
g) descendants are identical to parents
h) female and male sex cells
i) plants and animals
j) plants, microorganisms, lower animals
l) two
m) slowly
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 conditions environment on the development of the embryo (student message). Teacher comments on slides. 5. Information about newborns in the Tselinny district of the Republic of Kazakhstan (teacher's commentary) 6. Work of students with terms, filling out a dictionary of terms. 7. Consolidation and conclusions. II. Types of educational activities of students in the lesson: A). collection of information from various sources (textbooks, Internet), work on the Interactive board for drawing up tables, diagrams; B). understanding 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 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 in the table "Differentiation of cells", the performance of students with the messages "Embryonic induction", "On the harmful influence of environmental factors on development embryo ". IV. Materials for methodological support 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"; Lesson presentation; Quest cards; children's rubber ball; textbook General biology grades 10-11, A. Kamensky, E. Kriksunov, 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 - individual development 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 biological significance 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 derived 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).
Correctly ... 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 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 the book, with additional scientific literature, dumb tables, interactive whiteboard; develop the ability to prepare messages, analyze textbook drawings, generalize and draw conclusions, and identify patterns.
Upbringing - neat design of diagrams in a notebook; show negative influence alcohol, nicotine, drugs used without a doctor's prescription for 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 of the Russian Academy K.M. Baer is rightfully considered the founder of modern embryology. 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. Baer 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 – historical development the kind 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 a 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 the genetic information of the embryonic cells begins, and the first signs of differentiation appear.
3rd stage - Neyrula (primary organogenesis: the neural tube, notochord, intestinal tube are formed). When the 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 endoderm is under the nerve rudiment, separates from the rest of the endoderm and folds into a dense cord - chord. 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, outwardly identical blastomeres develop tissues, organs, and organ systems of various structures and functions.
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 chemical reactions, which flow 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). Signdrawing "Germ leaves", and also filling the table"Cell differentiation" (see Appendix 2)The interaction of parts of the embryoEmbryonic induction.
Teacher ... How, then, do the 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 body 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 dictionary of 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?Findings: 1. Academician of the Russian Academy K.M. Baer 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 the 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, narcotic substances, nicotine, sulfur dioxide and carbon have a negative effect on the development of the embryo and prevent the penetration of oxygen to 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
ATTACHMENT
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"Differentiation of cells"
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 environment.
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", student speeches with messages "Embryonic induction", "About harmful effects 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 10th grade 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 | Not | Not |
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 ontogenesis 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, 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; - students' independent work on the interactive board - filling in diagrams, tables; -Speech of students with messages
Multimedia projector; -interactive board; - 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 grades 10-11, 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 by VB Zakharov. See Figure 7.3, working on the interactive whiteboard. Sign the picture "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 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 to draw 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 cleavage, 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” - said L.N. Tolstoy. You are on the verge of an independent life. And we would really like your life path not overshadowed by trouble. 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!!!
The purpose of the lesson:
1. To generalize and synthesize knowledge about the individual development of organisms, using tasks to prepare for the Unified State Exam on this topic.
2. To practice the skills of solving tasks of part B and C2.
Tasks: To develop skills in working with tasks of part B and C.
Develop theoretical thinking.
Foster a responsible attitude towards your health.
Work on the instruction card. In which tasks are given that must be completed, instructions for the work that must be completed and the assessment of the result of part B - 2 points, part C, depending on the number of correct answers from 1 to 3 points.
The course of the biology lesson in grade 10: “Ontogenesis. Preparation for the Unified State Exam ".
1. Introduction
Life is the reproduction of one's own kind through those who are not similar.
How can this saying be explained? (Yes, we are talking about life cycles. Before an individual reaches the ability to reproduce, it will go through a number of dissimilar stages).
So, today we will focus on the features of the individual development of organisms.
Fill out the diagram:
What are the characteristics of each of the periods of ontogenesis? Complete task number 1 in the instruction card.
Task number 1
AT 6. Establish a correspondence between the periods of ontogenesis and its features
2. The embryonic period of development.
So the embryonic period of development, let's perform task number 2 to establish the sequence of phenomena and processes occurring in embryogenesis.
Task number 2.
AT 7. Establish the sequence of phenomena and processes occurring in embryogenesis.
A) neurulation
B) zygote
C) blastula
D) morula
D) gastrula
E) neurula
Answer: bgvdae
In preparation for the exam, you should pay attention to the tasks of part C2, work with drawings.
Task number 3
C2. Look at the picture and name the germ layer of the vertebrate animal indicated by the number 3. What types of tissues and organs are formed from it?
Answer:
1. Embryonic leaf under the number 3 - MESODERM
2. From the mesoderm, tissues are formed - connective and muscular.
3. From the mesoderm, organs are formed - the musculoskeletal system, the circulatory, excretory and reproductive systems
What organs are formed from ectoderm and endoderm? Complete the table with a plus sign.
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organs |
ectoderm |
endoderm |
mesoderm |
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Brain |
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Kidney |
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Bones and cartilage |
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Lungs |
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Blood |
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Intestines |
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Skin epithelium |
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Organs of hearing |
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Digestive glands |
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Muscle |
In the tasks for preparing for the exam, there are incorrect tasks or tasks with errors (typos).
What is the incorrectness of this task?
Task B6.
Set correspondence
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Body structure |
Germ leaves |
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A) liver B) senses B) skeleton D) leather D) brain E) circulatory system G) hearing organs H) spinal cord |
1) Ectoderm 2) Endoderm 3) mesoderm |
(Different layers of skin are formed from different germ layers. Epithelium from ectoderm, dermis and hypodermis from mesoderm).
Let's summarize the embryonic development of living organisms. Complete task number 4.
Task number 4
C2 Find errors in the text given
1. Ontogenesis begins with the formation of gametes in the body.
2. Gametes are involved in fertilization.
3. The zygote formed after fertilization is divided by meiosis.
4. After multiple division, a single-layer embryo is formed.
5. The embryonic period of development ends in vertebrates with the formation of a neurula.
Answers: 1. 3.5.
1. Ontogenesis begins from the moment the zygote is formed.
3. The zygote undergoes cleavage, which is based on mitosis.
5. The embryonic period of development ends in vertebrates after hatching or birth.
Which of the scientists embryologists introduced the concept of "ontogenesis" and what else is his merit as a scientist embryologist? (Haeckel, together with Müller, discovered the biogenetic law).
3. Postembryonic development.
Why did the post-fetal period of development become necessary in ontogeny?
(In an individual born (or hatched from an egg), all organs and tissues are not always fully formed. It is necessary that an adult is formed capable of reproducing its own kind).
What is direct development, indirect development, or development with metamorphosis? (direct - born individuals have all the organs characteristic of adult organisms, indirect - a new organism outwardly not similar to an adult, it has special larval organs).
What groups is it divided into? (in insects with complete and incomplete transformation)
What is the advantage of indirect development?
Larvae and adults often live in different conditions (there is no competition for a place).
Larvae and adults eat different foods (there is no competition for food).
Experiencing unfavorable environmental conditions (eg, insect pupa).
Complete task number 5.
AT 6. Set correspondence
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Organisms |
Postembryonic development methods |
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A) River cancer B) Dove C) Already ordinary D) Sharp-faced frog E) A quick lizard E) Medusa |
1) Direct 2) Indirect |
What stage is missing in incomplete transformation insects?
What insects is it typical for?
Working with information on a slide.
What stages of development does a butterfly go through?
What insects are characterized by this type of development?
Let's complete task number 6.
AT 6. Set correspondence:
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Organisms |
Development types |
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A) May beetle B) Cabbage white C) Bug water strider D) Green aphid E) Honey bee E) Asian locust G) Cockroach |
1) With complete transformation 2) With incomplete transformation |
3. Features of ontogeny of animals.
Ontogenesis of animals has its own distinctive features from the ontogeny of other organisms.
Task number 7
IN 3. What signs of development are manifested in animals only during ontogenesis?
1) Single cell stage
2) Protective coloring
3) Body measurements
4) Swimming membrane
5) Blastula
6) gastrula
Answer: 2 3 4.
The slide shows images of the stages of the developmental cycle of the hepatic fluke in the wrong sequence.
Set the sequence of stages in the developmental cycle of the hepatic fluke by completing task number 8.
Task number 8
AT 7. Establish a sequence of stages in the developmental cycle of the hepatic fluke, starting with the egg
A) The introduction of larvae into the body of the mollusk.
B) Exit from the egg of larvae with cilia.
C) The ingestion of cysts into the intestines of cattle.
D) The emergence of a floating tailed larva from the mollusk.
E) the release of fertilized eggs from the intestines into the environment.
E) encysting larvae.
Answer: dbaghev.
6. Human ontogenesis has its own characteristics both in embryonic (apoptosis of cells arising in the embryo at a certain stage of development) and in the post-fetal period, has its own critical periods.
Complete task number 8.
Q7. Establish the sequence of the processes of embryogenesis during the formation of identical twins in humans.
A) development of two organisms from neurula
B) gastrulation and the formation of a three-layer embryo
C) the formation of a fertilized egg
D) laying of embryonic rudiments in neurula
E) crushing the zygote and the formation of two blastula
Answer: c d b d a
Human ontogenesis has its own critical periods. Pay attention to the slide. And I would like to remind you of the well-known recommendations to reduce the risk of negative influences on a person during critical periods of ontogenesis.
Contribute to the preservation of a normal ecological situation;
Not to worsen, not now or in the future, the ecology of the native land;
Do not drink alcoholic beverages;
Do not smoke;
Do not take drugs;
Eat well;
Do sport.
Reflection:
Calculate the result of your work (points) and evaluate it according to the criteria, adding up the results of all tasks:
Criteria for evaluation:
"2" - 0 - 7
"3" - 8 - 11
"4" - 12 - 14
"5" - 15 - 20
And I would like to end our lesson with the words:
A child is a miracle, God's greatest gift that God can bestow on a person.
Download the presentation of a biology lesson in grade 10: “Ontogenesis. Preparation for the Unified State Exam ".
Lesson topic: Reproduction and individual development of organisms.
Thing: biology
Class: Grade 9
Lesson type : test lesson
Keywords: biology, lesson, non-traditional, knowledge control, reproduction, ontogenesis, metamorphosis
The purpose of the lesson: generalization and consolidation of knowledge about the forms and methods of reproduction of living organisms, the peculiarities of fertilization in plants and animals, the process of ontogenesis of living organisms.
Lesson objectives:
1. Conduct control of knowledge on the studied material, intensify development logical thinking by using active control methods; a differentiated approach to learning.
2. To form abilities and skills of working with terms, cards, test tasks, to develop interest in the subject.
3. To instill clarity and organization in independent work, give every student the opportunity to succeed.
Lesson equipment: tables on botany and zoology depicting mosses, ferns, mushrooms, angiosperms, protozoa, annelids, arthropods, chordates, test tasks, task cards, interactive whiteboard.
Lesson methods: visual, information and development, search and practical.
UMK: M.K.Gilmanov, L.U.Abshenova, A.R.Solovieva "Biology" Grade 9, Almaty "Atamұ ra ", 2009
During the classes:
Organizing time.
The teacher welcomes students, reveals the purpose and objectives of the lesson, introduces students to the assignments of the credit work and the criteria for evaluating work.
Note:
1. The teacher can evaluate each work separately for greater accumulation of marks for the lesson, or you can give a grade for each type of work and display one overall, or you can give one point for each work performed.
2. The teacher can check the completed assignments himself after the lesson or at the end of the lesson, students exchange work and check independently using the teacher's suggested keys.
Credit work:
1. Correlate concepts:
(match the term from the first column with the definition from the second column)
Term
Definition of the term
1. Reproduction
2. Sporulation
3.Fragmentation
4 metamorphosis
5. Parthenogenesis
6 hermaphroditism
7.Ovogenesis
8. Conjugation
9 gametogenesis
10. Sexual reproduction
11.Ontogenesis
12. Double fertilization
13 ectoderm
14 Blastula
15. Fertilization
1.Single-layer spherical embryo with a cavity inside.
2. The form of reproduction in which spores are formed.
3. The process of fusion of female and male gametes.
4. The process of oocyte formation.
5. A method of reproduction in which gametes participate.
6. Indirect postembryonic development of organisms.
7. The form of reproduction inherent in angiosperms.
8. A form of reproduction, in which an adult organism is divided into separate fragments.
9.Outer germ layer.
10. The form of reproduction in which the exchange of genetic material occurs.
11. Biological way to maintain your species.
12. The form of sexual reproduction, when different sex gametes mature in one organism.
13. Development of an organism from an unfertilized egg.
14. Individual development of the organism.
15. The process of formation of germ cells.
1-11; 2-2; 3-8; 4-6; 5-13; 6-12; 7-4; 8-10; 9-15; 10-5; 11-14; 12-7; 13-9; 14-1; 15-3.
2. Indicate the method of reproduction and its form in these living organisms:
Living organism
Breeding method
Reproduction form
1.euglena green
2.the dog is domestic
3.sphagnum moss
4. common raspberry
5.tubercular bacillus
6. champignon
7.the toad is green
8.polyp hydra
9. field horsetail
10.sea turtle
11.malaria plasmodium
12.Fern fern
13.tiger shark
14. yeast
15. earthworm
Asexual
Sexual
Asexual
Asexual
Asexual
Asexual
Sexual
Asexual
Asexual
Sexual
Asexual
Asexual
Sexual
Asexual
Sexual
Mitotic division
Internal fusion of gametes
Sporulation
Vegetative, natural, layering
Direct division
Sporulation
External fusion of gametes
Budding
Sporulation
Internal fusion of gametes
Schizogony
Sporulation
Internal fusion of gametes
Budding
Hermaphroditism
3. Test work on the topic "Reproduction and individual development of organisms"
1.What set of chromosomes are carried by sperm:
2. What set of chromosomes does the zygote have:
A) 1p; B) 2p; C) 3p; D) 4p; E) 5p.
3. What set of chromosomes do the somatic cells of the body have:
A) 1p; B) 2p; C) 3p; D) 4p; E) 5p.
4. What set of chromosomes does the endosperm of the embryo of the seed have:
A) 1p; B) 2p; C) 3p; D) 4p; E) 5p.
5. What set of chromosomes does a mammalian egg have:
A) 1p; B) 2p; C) 3p; D) 4p; E) 5p.
6.In which zone of gametogenesis does mitotic cell division occur:
7.In which zone of gametogenesis does meiotic cell division take place:
A) Breeding zone; C) Formation zone; C) Growth zone;
E) Ripening zone; E) Education area.
8. Which of the reproductive processes arose earlier than anyone else in the process of evolution:
A) Vegetative; C) Binary division; C) Budding; E) Sexual; E) Cuttings.
9.What is formed as a result of ovogenesis:
A) Gametes; C) Ovum; C) Sperm; E) Zygote; E) Somatic cells.
10. Which of the reproduction processes arose later than all in the process of evolution:
A) Vegetative; C) Asexual; C) Budding; E) Sexual; E) Binary fission.
11. What is formed as a result of gametogenesis:
A) Ovum; C) Sperm; C) Zygote;
E) Somatic cells; E) Sex cells.
12. What part of the sperm and egg is the carrier of genetic information:
A) Ribosomes; C) Centrioles; C) Mitochondria; E) The core; E) Lysosomes.
13. How many sperm contain a pollen grain:
A) 1; IN 2; C) 3; E) 4; E) 5.
14. What develops from the fertilized central cell, the embryonic sac of the ovary:
A) The embryo; C) Blastula; C) Sperm; E) Endosperm; E) Seed peel.
15. Sexual reproduction of Spirogyra:
A) Hermaphroditism; C) Gamete fusion; C) Self-fertilization;
E) Conjugation; E) Parthenogenesis.
Answers to test work:
1-a
2-in
3-in
4-s
5-in
6-a
7-d
8-in
9-in
10-d
11th
12-d
13-in
14-d
15-d
4. Determine the way of postembryonic development of organisms
(direct development or development with transformation - metamorphosis)
1.Cross Spider-Direct development
2.Marsh toad-Metamorphosis
3.Butterfly cabbage Metamorphosis
4.River cancerDirect development
5. Homo sapiens - Direct development
6 Asian Locust Direct development
8 common fly - Metamorphosis
9 black crow Direct development
10 honey bee - Metamorphosis
11.Red cockroach Direct development
12. Common newt - Metamorphosis
13. Itch itching - Direct development
14 Swamp Turtle- Direct development
15 green frog Metamorphosis
5. Determine from which germ layer organs are formed
(ectoderm, endoderm, mesoderm)
1.intestinalEndoderm
2.nails-Ectoderm
3.Light- Endoderm
4.heartMesoderm
5.seeds - Mesoderm
6.pancreas - Endoderm
7.leather Ectoderm
8.chord- Mesoderm
9.skeletal muscle - Mesoderm
10.stomach- Endoderm
11.Nerves- Ectoderm
12.brain Ectoderm
13. kidneys Mesoderm
14. urinary bladder Mesoderm
15. liver Endoderm
3. Checking the work performed.
Working in pairs:
Students exchange completed work with each other, the teacher on the interactive whiteboard opens the keys to each test assignment. Students check the work and enter the number of correct answers in the proposed table.
Last name, first name
1. Relate concepts
2.Method
and the form of breeding
3.Test work
4.Method of postembryonic development
5 germ layers
After filling out the tables, the teacher shows the criteria for assessing the work, the students give marks.
(all 5 tasks have 15 questions each to facilitate the assessment of the work performed)
15-13 rating "5"
12-9 rating "4"
8-6 rating "3"
less than 6 answers rating "2"
4. Reflection of the lesson.
Dear guys, I would like to finish our lesson with the words of A. Disterweg:
"You can offer a person knowledge, suggest, but he must master it through his own activity ..."
Guys, what is your opinion ... (students' comments)
5. Homework:
1. Make a presentation on the topic "Reproduction and individual development of organisms."
2. for students who received grades "4,3,2" to study this topic in more detail.
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 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, and 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 has microscopic dimensions, for example, 0.1 mm in mammals?(Due to cell division and growth). Correctly. 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 organogenesis3. 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 Greek embryon - embryo). Historical information: 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. INXVII century English physician and biologist W. Harvey made some experiments to test the theory of Aristotle. 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 is considered the founder of modern embryology Russian Academy K.M.Bair. 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, ontogenesis 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 go through 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). In this case, the 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. These 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 stepsThe 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 in 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 step is organogenesis. Thus, already in the early stages of the embryonic period of ontogenesis, tissues, organs and systems of different structure 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
THE INFLUENCE OF ENVIRONMENTAL CONDITIONS ON EMBRYO DEVELOPMENT.
In the embryonic period, the development of any organism depends on environmental conditions. 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 medicines 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 the placenta does not yet exist. 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 in the forming organs fewer cells are formed, the organs are underdeveloped. Nervous tissue is especially sensitive to a 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, low level voluntary attention; and 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 for the development of the embryo is the pollution of the habitat with various chemicals or exposure to ionizing radiation.
Drawing up a diagram of factors affecting the fetus in a notebook.
- And now, I'll read you an 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 the 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 and 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 stepsCrossword “Ontogenesis. Embryonic development "
1. Cells formed during the 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 mother's body that provides the embryo with respiration, nutrition, excretion, etc.
Form start
