Lesson topic: Reproduction and individual development of organisms.

Item: biology

Class: Grade 9

Lesson type : lesson-test

Keywords: biology, lesson, non-traditional, knowledge control, reproduction, ontogeny, metamorphosis

The purpose of the lesson: generalization and consolidation of knowledge about the forms and methods of reproduction of living organisms, the features of fertilization in plants and animals, the process of ontogenesis of living organisms.

Lesson objectives:

1. Conduct knowledge control on the studied material, activate the development of logical thinking through the use of active control methods; differentiated approach to learning.

2. To form the skills and abilities of working with terms, cards, test tasks, to develop interest in the subject.

3. To instill clarity and organization in independent work to give every student the opportunity to succeed.

Lesson equipment: tables on botany and zoology depicting mosses, ferns, fungi, angiosperms, protozoa, annelids, arthropods, chordates, test tasks, task cards, interactive whiteboard.

Lesson methods: visual, information-developing, search-practical.

UMC: M.K. Gilmanov, L.U. Abshenova, A.R. Solovieva "Biology" Grade 9, Almaty "Atamұ ra", 2009

During the classes:

Organizing time.

The teacher greets the students, reveals the purpose and objectives of the lesson, introduces the students to the tasks of the test work and the criteria for evaluating the work.

Note:

1. The teacher can evaluate each work separately for a greater accumulation of grades per lesson, or you can put a grade for each type of work and display one overall, or you can put one point for each completed work.

2. The teacher can check the completed tasks himself after the lesson or at the end of the lesson, the students exchange work and check it on their own according to the teacher's suggested keys.

Credit work:

1. Match concepts:

(to the term from the first column, select 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. Ontogeny

12. Double fertilization

13. Ectoderm

14. Blastula

15. Fertilization

1. A single-layer spherical embryo with a cavity inside.

2. Form of reproduction, in which spores are formed.

3. The process of fusion of female and male gametes.

4. The process of egg formation.

5. Method of reproduction in which gametes participate.

6. Indirect postembryonic development of organisms.

7. 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. Form of reproduction, in which the exchange of genetic material occurs.

11. A biological way to maintain your species.

12. A form of sexual reproduction, when different sexual 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. Specify the method of reproduction and its form in these living organisms:

Living organism

Reproduction method

Breeding form

1. euglena green

2. domestic dog

3. sphagnum moss

4. common raspberry

5. tuberculosis bacillus

6. champignon

7. green toad

8. polyp hydra

9. horsetail

10. sea ​​turtle

11. malarial plasmodium

12. fern shield

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 do spermatozoa carry:

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 seed germ 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 occur:

A) breeding area; C) Formation zone; C) growth zone;

D) Maturing zone; E) Education zone.

8. Which of the reproduction processes arose the earliest in the process of evolution:

A) vegetative; B) binary fission; C) budding; D) Sexual; E) cuttings.

9. What is formed as a result of oogenesis:

A) gametes; B) an ovum C) spermatozoon; D) Zygote; E) somatic cells.

10. Which of the reproduction processes arose later than all in the process of evolution:

A) vegetative; B) asexual; C) budding; D) Sexual; E) binary fission.

11. What is formed as a result of gametogenesis:

A) an ovum B) spermatozoid; C) zygote;

D) Somatic cells; E) sex cells.

12. What part of the sperm and egg is the carrier of genetic information:

A) Ribosomes; B) centrioles; C) mitochondria; D) the core; E) lysosomes.

13. How many sperm contains a pollen grain:

A) 1; AT 2; C)3; D) 4; E) 5.

14. What develops from the fertilized central cell, the embryo sac of the ovary:

A) embryo; B) Blastula C) sperm; D) Endosperm; E) seed coat.

15. Sexual reproduction of spirogyra:

A) hermaphroditism; C) fusion of gametes C) self-fertilization;

D) Conjugation; E) Parthenogenesis.

Answers to the 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 method of postembryonic development of organisms

(direct development or development with transformation - metamorphosis)

1. Spider-cross-direct development

2. Swamp toad-Metamorphosis

3. Butterfly-cabbage-Metamorphosis

4.Crayfish-direct development

5. A reasonable person -direct development

6.Asian locust-direct development

8. Common fly-Metamorphosis

9. Black Raven-direct development

10. Honeybee-Metamorphosis

11. Red cockroach-direct development

12. Triton ordinary -Metamorphosis

13. Scabies itch-direct development

14. Swamp turtle-direct development

15. Green frog-Metamorphosis

5. Determine from which germ layer organs are formed

(ectoderm, endoderm, mesoderm)

1.intestine-Endoderm

2.nails-ectoderm

3.light-Endoderm

4.heart-mesoderm

5.testes-mesoderm

6.pancreas-Endoderm

7.leather-ectoderm

8.chord-mesoderm

9.skeletal muscles-mesoderm

10.stomach-Endoderm

11.nerves-ectoderm

12.brain-ectoderm

13.kidney-mesoderm

14.bladder-mesoderm

15. liver-Endoderm

3.Checking the work performed.

Work in pairs:

The students share their completed work with each other, the teacher interactive whiteboard opens the keys to each test task. Students check the work and enter the number of correct answers in the proposed table.

Last name, first name

1. Correlate concepts

2.Way

and form of reproduction

3.Test work

4. Method of postembryonic development

5. Germ sheets

After filling in the tables, the teacher shows the criteria for evaluating the work, the students give grades.

(all 5 tasks have 15 questions each to facilitate the assessment of work performed)

15-13 rating "5"

12-9 rating "4"

8-6 rating "3"

less than 6 answers score "2"

4. Lesson reflection.

Dear children, I would like to finish our lesson with the words of A. Diesterweg:

“You can offer knowledge to a person, suggest, but he must master them through his own activity ...”

Guys, what is your opinion ... (students' statements)

5. Homework:

1. make a presentation on the topic "Reproduction and individual development of organisms."

2. Pupils who received grades "4,3,2" study this topic in more detail.

Answers to school textbooks

The reproduction of organisms is the process of reproduction of their own kind, ensuring the continuity and continuity of life. This property is characteristic only for living organisms, in which they fundamentally differ from objects of inanimate nature.

2. What is the essence of asexual reproduction?

In the process of evolution, asexual reproduction arose first, and only later - sexual.

With asexual reproduction, a new generation is formed with the participation of only one parental individual, which completely transfers to it all its hereditary qualities and characteristics. Mitotic cell division underlies all forms of asexual reproduction.

This method of reproduction is found in nature (among animals - in protozoa, coelenterates, worms, etc., as well as in most plants) and is used in the national economy: in the microbiological industry for the propagation of bacteria and yeast; V agriculture in vegetative propagation of plants and in tissue culture technology.

3. What types of asexual reproduction do you know?

Most simple form asexual reproduction - division, when the parent individual is divided into two identical parts. This is how bacteria, protozoa, and many unicellular algae reproduce.

Another form of asexual reproduction is budding. It is found in both unicellular (yeast) and multicellular (hydra) organisms. Such a process of asexual reproduction as sporulation is quite widespread in nature (this is how fungi, algae, mosses, ferns and some unicellular animals reproduce).

There is also a process of fragmentation, when a child (filamentous algae, planaria) is formed from a part of the mother's organism. At the heart of this process is the ability of the body to restore lost parts of the body.

Plants are widespread vegetative reproduction, in which new individuals are formed from parts of the mother plant (shoot, root) and at the same time inherit all its characteristics. Some plants have special modified organs for this: bulbs, corms, tubers, rhizomes. Many of them also serve as storage organs, in which nutrients, allowing the plant to survive the unfavorable period - winter, drought.

4. How does asexual reproduction occur in protozoa?

asexual reproduction in the simplest it is carried out by division. This process starts from the kernel. It stretches, takes an oblong shape, then divides by mitosis. Daughter nuclei move away from each other. A transverse constriction or septum is formed in the cytoplasm, which, gradually deepening, divides the maternal individual into two daughters.

5. What is budding?

Budding is a form of asexual reproduction. It occurs in both unicellular and multicellular organisms. For example, this is how unicellular fungi and yeast reproduce. Initially, a small tubercle is formed on the mother cell - a kidney. It grows, increases in size. The nucleus of the mother cell divides. Then one of the formed daughter nuclei moves to the kidney. A new cell is formed. She can continue to live with her mother or separate from her and go on to an independent existence.

6. What organisms reproduce by budding?

Both unicellular and multicellular organisms reproduce by budding. This is how unicellular yeast fungi reproduce. The multicellular hydra uses the same method of reproduction, however, its kidney is formed by a group of cells.

7. Does budding occur in plants?

In plants, budding can be observed, for example, in Kalanchoe. On its leaves there are special large cells from which small plants are formed.

8. What is a dispute?

A spore is a special type of cell with very hard shells. Disputes can long time to be at rest. In this form, they are able to wait out the cold, heat, drying, excess moisture. When favorable conditions come, they germinate, divide, and new individuals are formed from them.

9. What organisms reproduce by spores?

Some unicellular animals, fungi and many plants reproduce by spores. In multicellular plants, such as multicellular algae, mosses, ferns, as well as in higher fungi, spores are formed in special organs - sporangia.

10. Which organs flowering plant called vegetative?

The vegetative organs are the shoot (stem with leaves and buds) and the root.

11. What method of reproduction is called vegetative?

Vegetative is a method of reproduction in which new individuals are formed from parts of the mother plant (shoot, root) and inherit all of its characteristics. Some plants have special modified shoots for this: bulbs, corms, tubers, rhizomes.

OPTION 1.

1. Which of the following definitions is correct?

a) reproduction is an increase in the number of individuals of a given species due to migration from another territory; b) reproduction is an increase in the number of individuals of a given species through development on the basis of parental organisms.

2. List the features of spermatogenesis:

a) occurs in the female body; b) proceeds in the testis; c) includes 4 periods;

d) begins in embryogenesis; e) proceeds in the ovary; e) begins at puberty; g) includes 3 periods; h) ends with the formation of 4 gametes;

i) ends with the formation of 1 gamete; j) occurs in the male body.

3. Determine with which organs fertilization is associated: a) ovary;

b) fallopian tubes;

c) seminal vesicles; d) uterus; e) seed.

4. In what zone does meiosis occur during gametogenesis?

a) reproduction; b) growth; c) maturity.

5. What part of the egg is the carrier of genetic information?

a) cytoplasm; b) ribosomes; c) core; d) mitochondria.

TESTS ON THE TOPIC: "BREEDING OF ORGANISMS.

FEATURES OF HUMAN REPRODUCTION".

OPTION 2.

1. List the main features of asexual reproduction: a) one parent individual; b) the offspring is genetically unique; c) the main cellular mechanism is meiosis; d) two parent individuals; e) the development of a descendant from the cells of the body; e) offspring are genetically similar; g) the main cellular mechanism is mitosis; h) development of a descendant from gametes.

2. List the features of oogenesis: a) proceeds in the female body; b) proceeds in the testis; c) includes 4 periods;

d) begins in embryogenesis; e) proceeds in the ovary; e) begins at puberty; g) includes 3 periods; h) ends with the formation of 4 gametes; i) ends with the formation of 1 gamete; j) occurs in the male body.

3. Determine with which organs maturation of the egg is associated: a) ovary; b) fallopian tubes; c) seminal vesicles; d) uterus; e) seed.

4. What is the set of chromosomes in spermatozoa?

5. What human germ cells are involved in fertilization?

a) an ovum b) spermatozoon; c) oocyte II; d) spermatid.

TESTS ON THE TOPIC: "BREEDING OF ORGANISMS.

FEATURES OF HUMAN REPRODUCTION".

OPTION 3.

1. List the main features of sexual reproduction: a) one parental individual; b) the offspring is genetically unique; c) the main cellular mechanism is meiosis; d) two parent individuals; e) the development of a descendant from the cells of the body; e) offspring are genetically similar; g) the main cellular mechanism is mitosis; h) development of a descendant from gametes.

2. Specify the structural features of the spermatozoon:

3. Determine with which organs the formation of spermatozoa is associated: a) ovary; b) fallopian tubes; c) seminal vesicles; d) uterus; e) seed.

4. What is the set of chromosomes in an egg?

5. How many spermatozoa must be contained in semen for fertilization to occur?

a) 150; b) 1500; c) 15000; d) 150000000.

TESTS ON THE TOPIC: "BREEDING OF ORGANISMS.

FEATURES OF HUMAN REPRODUCTION".

OPTION 4.

1. Specify the main forms of asexual reproduction: a) multiple fission; b) parthenogenesis; c) simple division; d) fragmentation; e) budding; f) vegetative reproduction; g) spore formation; h) with fertilization.

2. Specify the structural features of the ovum:

a) large sizes; b) a large volume of cytoplasm; c) haploid nucleus; d) small volume of cytoplasm; e) the presence of a tail; e) small size; g) the presence of an acrosome; h) yolk reserves.

3. What gametes are produced by the testes?

a) eggs b) spermatozoa.

4. Which of the methods of reproduction of organisms arose later than all in the process of evolution?

a) vegetative; b) asexual; c) sex.

5. How long does an egg exist in a person?

a) 48 hours; b) 24 hours; c) 72 hours; d) 12 hours.

42. Compare the processes of mitosis and meiosis.

Mitosis is a cell division that results in two cells with the original set of chromosomes (2n if the mother cell was diploid, and 1n if the cell was haploid, for example, when pollen is formed from microspores); Mitosis is an asexual process of reproduction. During meiosis, as a result of two successive divisions, in the second of which no copies of chromosomes are formed, four haploid (n) cells are formed from the original diploid cell (2n). In this case, the recombination of hereditary traits is carried out due to crossing over, which occurs in prophase I of meiosis. (Importance of mitosis and meiosis - see answers to questions 37 and 41).

43. What are the features of the formation and structure of male and female germ cells?

Male sex cells (gametes) - spermatozoa - are formed as a result of spermatogenesis (gr. sperm- seed and genesis- birth).
This process occurs in three stages: reproduction in the testes of diploid cells of spermatogenic tissue, resulting in the formation of spermatocytes (2n); growth of spermatocytes, accompanied by DNA synthesis and completion of the second chromatid; maturation of spermatocytes, which divide by meiosis to form haploid (n) spermatozoa.
Chromosomal sets of spermatozoa (human and other mammals) differ in sex chromosomes: some carry the X-chromosome, while others carry the Y-chromosome.
Female sex cells (gametes) - eggs - are formed as a result of oogenesis (gr. UN- an egg and genesis- birth).
This process also occurs in the ovaries in three stages: reproduction in the ovaries of diploid cells of the oogenic tissue, as a result of which oocytes (2n) are formed; oocyte growth, accompanied by DNA synthesis and the construction of the second chromatid of chromosomes; maturation of oocytes and their division by meiosis. As a result, one haploid egg with single chromatid chromosomes (1n1c) and three reduction (or polar) bodies are formed from the oocyte. In the future, the egg participates in the sexual process, and the reduction bodies die off.
The process of formation of male and female gametes is called gametogenesis(Fig. 19).

Rice. 19. Scheme of spermatogenesis ( A) and oogenesis ( b)

Differences in the structure of sperm and eggs are associated with their functions. In the process of maturation, the eggs are covered with shells (in some cases, for example, in reptiles, birds and mammals, a number of additional shells appear). The function of the membranes is to protect the egg and embryo from external adverse influences.
The function of spermatozoa is to deliver genetic information to the egg and stimulate its development. In this regard, a significant restructuring occurs in the spermatozoa: the Golgi apparatus is located at the anterior end of the head, transforming into a ring body (acrosome), which secretes enzymes that act on the egg shell. Mitochondria are compactly packed around the emerging flagellum, forming a neck. The formed spermatozoon also contains centrioles.

44. Expand the biological meaning of the process of fertilization.

Fertilization is the process of fusion of a spermatozoon with an egg, followed by the fusion of their nuclei and the formation of a diploid zygote. The biological significance of this process lies in the fact that when male and female gametes merge, a new organism is formed that carries the characteristics of both parental organisms. During the formation of gametes in meiosis, cells with different combinations of chromosomes arise, therefore, after fertilization, new organisms combine the characteristics of the father and mother in various combinations. As a result, the hereditary diversity of organisms increases significantly.

45. What method of reproduction evolved earlier? Bring evidence.

More ancient in evolutionary terms is asexual reproduction; proof of this is the fact that this type of reproduction is characteristic of prokaryotes - bacteria and cyanobacteria - the first organisms that appeared on Earth.
In this case, the cells receive the same hereditary information that was contained in the original (mother) cell.

46. ​​Justify the evolutionary advantage of sexual reproduction over asexual reproduction.

For the advantages of sexual reproduction over asexual reproduction, see answers to questions 44 and 45.

47. Describe the main stages of embryonic development. What signs at different stages of development of the human embryo indicate its animal origin?

Embryonic development is the development of an animal from the appearance of a zygote to birth. The first stage - blastula(gr. blastos- germ): the embryo has the shape of a multicellular single-layer ball, hollow inside. All nuclei of blastomere cells are diploid and contain the same genetic information. Usually there are 64 (sometimes 128 or more) blastomeres in the blastula. The size of the blastula does not exceed the zygote. The cavity inside the blastula is primary (blastocoel). Second stage - gastrula(gr. gaster- stomach): the embryo is two-layered, it has an intestinal cavity, a primary oral opening, two layers of cells - ectoderm and endoderm. This is followed by the stage of late gastrula (in all animals except sponges and coelenterates). At this stage, a third layer of cells appears - the mesoderm, which is laid between the ecto- and endoderm. Initially, it looks like two pockets, the cavities of which are a secondary cavity of the body. In the embryo of chordates, this is followed by the stage neurula- an axial complex is formed, consisting of a chord and a neural plate, located parallel to each other. The notochord arises from the endoderm (more precisely, from the chordomesoderm), and the neural plate from the ectoderm.
In the future, cell differentiation occurs: from the ectoderm, the integumentary epithelium, tooth enamel, nervous system, sense organs. From the endoderm - the intestinal epithelium, digestive glands, lungs. From the mesoderm - the skeleton, muscles, circulatory system, excretory organs, reproductive system. In all animals and in humans, the same germ layers form the same organs and tissues. This is evidence that the germ layers are homologous and have a common origin in evolution. Further development of the embryo proceeds in strict dependence of some organs on others (G.Speman's law of embryonic induction).

48. What is the subject of genetics and what are its tasks and methods?

Genetics is the science of the laws of heredity and the variability of organisms. Genetics develops methods to control these processes. It includes a number of branches - the genetics of microorganisms, plants, animals, humans. Genetic methods are used, for example, in medicine (medical genetics). Genetics is closely connected with molecular biology, cytology, evolutionary theory, selection.
The results obtained in genetic research are of great importance for medicine, genetic engineering, biotechnology and other fields.
In different departments of genetics, different methods are used: hybridological in plant genetics, genealogical, twin, cytogenetic, biochemical - in human genetics, etc.

49. Define heredity and reveal its content with specific examples.

Heredity is the property of organisms to pass on to the next generation their signs and features of development, i.e. reproduce their own kind. Heredity is an integral property of living matter. It is due to the relative stability (i.e., structure constancy) of DNA molecules.
The existence of heredity is confirmed by the similarity of the external and internal features of the offspring with the corresponding features of the parent organisms.

50. Expand the universal nature of the code of heredity as proof of the material unity of living nature.

The hereditary (genetic) code is a single system of "recording" hereditary information in a DNA molecule in the form of a sequence of nucleotides. This code is universal for all organisms. The most important properties of the code are tripletness, universality, specificity (see also questions 27 and 29).

51. What are the cytological foundations of inheritance patterns?

Cytology is a science that studies the structure and activity of cells. At the time when G. Mendel published his observations on the nature of the inheritance of traits in peas (1865), he could not know about the structure of gametes, mitosis, meiosis, the structure and purpose of DNA, etc. The development of cytology and others biological sciences made it possible to establish that chromosomes consist mainly of DNA molecules, that genes are sections of DNA, that each cell of the body contains a double set of chromosomes (one from each parent), and hence two genes that determine each trait, and the exception are only sex cells (gametes). All this information made it possible to give G. Mendel's discoveries a cytological substantiation.
Consider the cytological foundations of monohybrid crossing, that is, such crossing, when two pea plants belonging to pure lines differ in only one trait, for example, the color of seeds (peas). In this case, the parent plants are denoted by the Latin letter P (from the English. parents- parents), the female - a sign (mirror of Venus), the male - a sign (shield and spear of Mars). Crossing is indicated by the multiplication sign x, plants of the first generation are indicated by the sign F 1 - (from lat. filia- sons). The predominant color of the seeds, in this case yellow, is called dominant(from lat. domine- mister) and are denoted by a capital letter A, and the suppressed color, in this case green, - recessive(from lat. recessivus- retreat) and are denoted by a small letter a.
Having adopted such designations, monohybrid crossing can be depicted as follows.

Since during the formation of gametes there is a decrease in the number of chromosomes (and hence genes) in these cells by half, then in each gamete there will be only one seed color gene: either “yellow” or “green”. During the formation of hybrids of the first generation (from hybrid- crossbreed) the gametes merge, the diploid set of chromosomes is restored, and each F 1 cell carries the genes for both yellow and green seeds. But in the phenotype, only yellow color will appear, which in this case dominates. This pattern, discovered by G. Mendel, was called dominance rules, or Mendel's first law.

52. Explain the reasons preventing the exchange of genes between organisms of different species.

One of the most important properties of any kind is the so-called reproductive isolation, that is, the presence of special mechanisms that prevent the introduction of genes of an alien species into one's own gene pool. If there were no such mechanisms, then the species could not exist as an evolutionary unit. Especially important is the reproductive isolation of closely related species, the probability of crossing of which is higher than that of genetically distant ones. Protection against the influx of foreign genes can be achieved in various ways.
For example, the timing of maturation of gametes in closely related species may differ. Thus, the timing of spawning in closely related species of fish that breed in the same places does not coincide. The breeding sites may not match. For example, different types of frogs lay their eggs in different bodies of water: puddles, lakes, rivers, etc. One form of isolation may be a preferred habitat: some species of buttercups grow in meadows, others in swamps, and still others in forest edges. In addition, the egg is usually able to recognize the spermatozoa of males of its own species, and "foreign" spermatozoa cannot penetrate it. If this happened, and an interspecific hybrid was born, then usually it is either not viable or sterile. For example, a hybrid of a horse and a donkey - a mule, which is distinguished by great endurance, is sterile due to the fact that the non-homologous chromosomes of a donkey and a horse cannot conjugate during meiosis and the formation of full-fledged gametes in a mule is impossible.
Thus, a whole set of reproductive isolation mechanisms creates reliable protection against the penetration of any kind of foreign genes into the gene pool. This makes each species a stable stage of evolution of the organic world that really exists for very long periods of time.

53. Describe the concepts of "gene", "allele", "homozygous", "heterozygote", "dominance", "recessiveness" and illustrate them with examples.

The terms listed in the question denote the basic concepts of genetics - the science of heredity and variability.
Gene(from gr. genos- genus, origin) is a section of the DNA molecule that determines the inheritance of a particular trait. Since DNA molecules are twisted into chromosomes during division, we can say that a gene is a section of a chromosome.
Since the somatic cells of organisms contain a double (diploid) set of homologous chromosomes, one from each parent individual, therefore, there are two genes that determine the development of each trait in the cell. They are located in strictly defined areas of homologous chromosomes - loci. Genes responsible for the development of some trait and lying in the same loci of homologous chromosomes are called allelic genes, or allele. All gametes in an individual of a pure line AA (or purebred) are the same, that is, they contain gene A. These individuals are called homozygous on this basis (from gr. homos- equal). Individuals with Aa genes form two types of gametes A and a in a ratio of 1:1. Such individuals are called heterozygous(from Greek. heteros- various). The predominant variant of the trait of the two possible is called dominant(from lat. domine- master), and the suppressed - recessive(from lat. recessivus- retreat). For example, when considering the color of pea seeds, G. Mendel found that their yellow dominates green.

54. Define the terms "phenotype" and "genotype". What is their fundamental difference? How is the genotype related to the phenotype from the point of view of molecular biology and evolutionary theory?

The totality of all the features of one organism, both external and internal, is called phenotype. The totality of all genes in an organism is called genotype. Genes are passed on from generation to generation without changing. Changes occur only with mutations, which are rarely observed. However, the manifestations of the action of genes and the nature of the emerging trait depend to a large extent on environmental conditions. Thus, the phenotype is determined by the genotype and environmental conditions. Strictly speaking, it is not the trait itself that is inherited, but the ability of the organism to demonstrate the trait under certain conditions of existence.
A gene defines the structure of a single protein, usually with important properties for the organism, such as enzymatic activity. Through the synthesis of proteins or the regulation of other important processes with the help of enzymes, the manifestation of one or another sign is carried out.

55. What kind of crossing is called monohybrid and what are its cytological bases? What rules and patterns are manifested in monohybrid crossing? Illustrate them with examples.

A monohybrid is a crossing of two organisms that differ from each other in only one trait. It was with monohybrid crossing that G. Mendel began his studies of the laws of heredity. He crossed two pea plants, differing from each other only in the color of the peas: yellow and green. In the first generation, all the peas were yellow. Thus, G. Mendel found that the yellow color of the seeds suppresses green color, or dominates. This pattern has been named dominance rules and is sometimes called Mendel's first law(see answer to question 51).
However, G. Mendel did not stop at the analysis of the study of the color of peas in the first generation. He crossed two heterozygous plants from the first generation. In the second generation, splitting occurred and plants appeared not only with yellow, but also with green seeds in a ratio of 3: 1.

This pattern has been named splitting rules for second generation hybrids, or Mendel's second law. Mendel also established that the patterns he discovered apply not only to the color of seeds, but also to the color of flowers, the shape of seeds, and so on.
A number of conclusions can be drawn from experiments on monohybrid crossing.

1. Organisms pass genes from generation to generation without changing them. This is confirmed by the fact that there were no green peas in the first generation, but the gene a that determines this color was transferred unchanged from F 1 to F 2, where the seeds of recessive aa homozygotes are green.

2. One of the genes that determine each trait suppresses the other, that is, dominates it. This conclusion of Mendel is true for pea traits, but there may be other relationships between genes.

3. Considering the patterns of splitting that occurs when two heterozygous peas are crossed, Mendel suggested that hereditary factors (which we now call genes) do not change and do not mix during the formation of hybrids, remaining unchanged. Communication between generations is carried out only through germ cells - gametes. Having discovered the appearance in F 2 of 25% of individuals with a recessive trait of parents - green seeds - Mendel found that this can only happen if the following condition is met: when germ cells are formed, only one hereditary factor (i.e. gene) from the allelic couples. This is the formulation of Mendel's hypothesis, called law of gamete purity.
The cytological substantiation of this law is that meiosis occurs during the formation of germ cells, as a result of which four haploid gametes (n) are formed from one diploid cell (2n). Naturally, in a single set of gamete chromosomes there can be only one gene that determines any trait (allelic pair).

56. What rules and patterns are manifested in dihybrid crossing? Illustrate them with examples.

In nature, organisms of the same species differ from each other in many ways. Therefore, monohybrid crossing, like dihybrid crossing, can be observed only in the experiment. What are the patterns of inheritance in the case when organisms differ in two characteristics, that is, in dihybrid crossing?
G. Mendel chose two parental homozygous plants that differ only in color (yellow and green) and shape (smooth and wrinkled) seeds. In this case, the yellow color (A) and the smooth shape (B) dominate, while the green color (a) and the wrinkled shape (b) are recessive traits.

Thus, as a result of crossing in the first generation (F 1), heterozygous individuals of AaBb are formed, containing genes for both dominant and recessive traits. According to the dominance rule, they will have yellow smooth peas.
Each plant in F 1 produces four types of gametes: namely, 25% AB, Ab, aB and ab. When crossing, all possible random fusions of these four types of gametes can be depicted using the so-called Punnett lattice. In its 16 squares, genotypes and phenotypes are written, which are formed in F 2 during dihybrid crossing.

From a consideration of the results of this crossing, it is obvious that, according to the phenotype, the offspring are divided into 4 groups: 9 yellow smooth, 3 yellow wrinkled, 3 green smooth, 1 green wrinkled. But if we consider the splitting according to one trait, that is, according to the color of the seeds, then the ratio of yellow to green and smooth to wrinkled will be 12:4 = 3:1, as in a monohybrid cross. This pattern has been named independent splitting rules, or independent feature combination. Later she was called Mendel's third law. The wording of this rule is as follows: when crossing two homozygous individuals that differ from each other in two pairs of traits, splitting for each pair of traits occurs independently of other pairs. It should be mentioned right away that this rule is valid only if the genes of the pairs of traits under consideration lie in different pairs of homologous chromosomes.

57. Expand the essence of the law of purity of gametes. What is its cytological rationale?

Considering the patterns of splitting that occurs when two heterozygous peas differ only in seed color, Mendel suggested that hereditary factors (which we now call genes) do not change and do not mix during the formation of hybrids, remaining unchanged. Communication between generations is carried out only through germ cells - gametes. Having discovered the appearance in F 2 of 25% of individuals with a recessive trait of parents - green seeds, Mendel found that this can only happen if the following condition is met: when germ cells are formed, only one hereditary factor (that is, a gene) from an allelic pair enters each of them . This is the formulation of Mendel's hypothesis, later called gamete purity law. The cytological substantiation of this law is that meiosis occurs during the formation of germ cells, as a result of which four haploid gametes (n) are formed from one diploid cell (2n). Naturally, in a single set of gamete chromosomes there can be only one gene that determines any trait (allelic pair).

58. What is the multiple action of genes and what are the reasons for this phenomenon?

In his experiments, G. Mendel studied peas. Those signs of peas, the inheritance of which was studied by G. Mendel - the color or shape of the seeds - are determined by individual genes. However, not always one gene determines the inheritance of only one trait. The phenomenon when one gene is responsible for the development of a number of traits is called multiple gene action. So, for example, a defect in one gene leads to the development of Marfan's syndrome: in patients, flexible long fingers (“spider fingers”), dislocation of the lens of the eye, and a violation in the structure of the heart. In this case, all these signs are based on the abnormal development of connective tissues, caused by the action of just one gene.

59. Expand the essence of analyzing crossing. What is its practical significance?

The genotype is the totality of all genes, and the phenotype is the totality of all the traits of an organism. Moreover, if the phenotype is dominant, it is impossible to establish the genotype. For example, pea plants that have yellow seeds can have both Aa and AA genotypes. In order to establish whether such a plant is homozygous or heterozygous, an analysis cross is carried out. To do this, a plant with an unknown genotype and a homozygous plant with a recessive trait aa are crossed. If the analyzed individual has a homozygous set of genes - AA, then splitting will not occur in the first generation.
If the plant under study is heterozygous Aa, then in the first generation there will be individuals with a recessive trait, that is, with green seeds.

So you can establish the unknown genotype of an individual with a dominant phenotype.

60. What is the essence of G. Mendel's third law and what are its cytological foundations?

See answer to question 57.

61. Expand the main provisions of the chromosome theory of heredity. What is the essence of T. Morgan's law?

In 1910–1920 American geneticist Thomas Morgan formulated the chromosome theory of heredity.
According to this theory, genes are segments of chromosomes. Those. A chromosome is a group of genes connected in series - a linkage group. Now we know that a chromosome is a DNA molecule and, therefore, a gene is a section of this molecule. All cells of organisms of the same species contain a certain number of paired (homologous) chromosomes - 2n. The number n for a person is 23. Thus, our cells contain 46 chromosomes, and only in germ cells - spermatozoa and eggs - 23 each. Each gene has a strictly defined place in the chromosome. This place is called locus of this gene.
Genes located on the same chromosome are inherited together, and for the traits determined by these genes, Mendel's law of independent inheritance of traits is unfair. The phenomenon of joint inheritance of genes located on the same chromosome is called linked inheritance, or Morgan's law. A heterozygous individual that has two genes on the same chromosome

will form two types of gametes A B And a b in a ratio of 1:1. However, in addition to such gametes, gametes can be formed in a small amount. a B And A b, since the allelic genes a and A or b and B can change places, moving from one homologous chromosome to another. This phenomenon, also discovered by Morgan, is called crossover of homologous chromosomes, or crossing over.

62. What are the cytogenetic bases and biological significance of the crossing over process?

According to T. Morgan's law, genes located on the same chromosome are inherited together, i.e. linked. However, it turned out that Morgan's law is sometimes violated when chromosomes cross, or crossing over. A heterozygous individual that has two genes A and B in one of the two homologous chromosomes and genes a and b in the other of them, according to Morgan's law, can form two types of gametes:

However, in reality, in addition to such gametes, a certain number of gametes are also formed. a B And A b, that is, Morgan's law is violated. This occurs during the prophase of the first division of meiosis, when homologous chromosomes approach and conjugate. In the process of conjugation, they can exchange sites with allelic genes.

The further the genes are located in the chromosome, the greater the probability of crossing over between them and the higher the percentage of gametes with recombination of genes, which means that a greater percentage of offspring individuals differ from their parents. Thus, crossing over is an important source of combinative variability.

63. Describe the chromosomal mechanism of sex determination in humans and animals.

The cells of organisms contain a double set of homologous chromosomes, which are called autosomes, and two sex chromosomes. The cells of females contain two homologous sex chromosomes, which are commonly referred to as XX. In the cells of males, the sex chromosomes are not paired - one of them is designated X and the other Y. Thus, the chromosome set in men and women differs by one chromosome. Women have 44 autosomes and two XX sex chromosomes in each cell of the body (except sex), while men have the same 44 autosomes and two sex chromosomes X and Y. When germ cells are formed, meiosis occurs and the number of chromosomes in sperm and eggs decreases by two times. In women, all eggs have the same set of chromosomes: 22 autosomes and an X chromosome. In men, two types of spermatozoa are formed in a ratio of 1: 1 - 22 autosomes and X or 22 autosomes and a Y chromosome. If a sperm containing the X chromosome enters the egg during fertilization, a female embryo will appear, and if a sperm contains a Y chromosome, a male embryo is formed.
Thus, sex determination in humans, other mammals, Drosophyll, depends on the presence or absence of the Y chromosome in the sperm that fertilizes the egg. The opposite picture is observed in birds and many fish: XY is the set of sex chromosomes for females, and XX for males. In some insects, such as bees, females have XX chromosomes, while males have only one X sex chromosome, and there is no pair for it. Therefore, in the animal world, chromosomal sex determination may vary.

64. Expand the features of the inheritance of sex-linked traits.

The X and Y sex chromosomes contain a large number of genes. The inheritance of the traits they define is called sex-linked inheritance, and the localization of genes in the sex chromosomes is called linkage of genes to sex.
For example, the human X chromosome contains the dominant H gene, which determines blood clotting. A person who is recessively homozygous for this trait develops a severe disease of hemophilia, in which the blood does not clot and the person can die from the slightest damage to the vessels. Since there are two X chromosomes in women's cells, the presence of the h gene in one of them does not entail a disease, since the dominant H gene is present in the second of them. In the cells of men, there is only one X chromosome. If the h gene is present in it, then the man will develop hemophilia, since the Y chromosome is not homologous to the X chromosome and does not contain the H or h gene.
Let's write a scheme of inheritance of hemophilia.

Similarly, color blindness is inherited - a congenital inability to distinguish colors, most often green and red.

65. What is the interaction of genes and what is the reason for this phenomenon?

Not always one gene determines the inheritance of one trait. The genotype is a system of interacting genes. In this case, both allelic and non-allelic genes can interact with each other. The interaction of allelic genes according to the principle of dominance–recessivity was discussed above. In addition, incomplete dominance is often encountered, in which heterozygous individuals differ in phenotype from homozygous ones. For example, if A is the gene for the dominant red color, and a is the gene for the recessive white color of the flower, then an individual with the AA genotype has red flowers, aa is white, and Aa is pink.
The following types of interaction of non-allelic genes are often observed.

1. Complementarity.

Complementary genes are called dominant genes, in the presence of which a trait develops in the AB genotype, in contrast to the cases of Ab or aB, when this trait is absent.

2. Epistasis.

In this case, the genes of one allele suppress the action of other genes that are not allelic to them.

3. Polymer action of genes.

Many properties of living organisms (weight, size, fecundity) cannot be divided into clear phenotypic classes. Such signs are called quantitative. Most often, they are controlled not by one, but by several pairs of non-allelic genes.
What are the reasons for the interaction of genes? A protein synthesized with the participation of a gene may be an enzyme necessary for the manifestation of the action of another protein encoded by a completely different gene. This can explain the complementary interaction of non-allelic genes. In other cases, one protein is able to suppress protein synthesis that occurs with the participation of another gene - this is how epistasis manifests itself.
Quantitative features are actually a whole set of simpler features. For example, for high fertility in a pig, a large number of eggs must simultaneously mature, a pig must have a certain size of the uterus, a large number of mammary glands, etc. Naturally, all these signs are determined by different alleles of genes.

66. Describe the types of mutations known to you. What is their significance in the evolutionary process, in practical activities?

Sometimes, during the transfer of genetic material from parents to offspring, quantitative or qualitative changes occur in DNA, and the daughter cells receive a set of genes that differs from the parent ones. Such changes in hereditary material that are passed on to the next generation are called mutations(from lat. mutatio- turn). An organism that acquires new properties as a result of a mutation is called mutant. The mutation theory was developed at the beginning of the 20th century. Dutch cytologist Hugo de Vries.
Mutations have a number of properties.

1. Arise suddenly, any part of the genotype can mutate.
2. More often they are recessive, less often - dominant.
3. Can be harmful, neutral and beneficial to the body.
4. Passed down from generation to generation. They can occur under the influence of both external and internal influences.

Mutations are divided into several types. Point, or genetic, mutations are changes in individual genes that can occur when one or more nucleotide pairs are replaced, dropped or inserted in a DNA molecule.
Chromosomal Mutations are changes to parts of chromosomes or whole chromosomes. Such mutations can occur as a result of: deletions - the loss of part of the chromosome; duplications - doubling of any part of the chromosome; inversions - rotation of a chromosome segment by 180 o; translocation - tearing off part of the chromosome and moving it to a new position, for example, joining another chromosome.
Genomic mutations consist in changing the number of chromosomes in the haploid set. this may occur as a result of the loss of any chromosome from the genotype or, conversely, an increase in the number of copies of any chromosome in the haploid set. A special case of genomic mutations - polyploidy– an increase in the number of chromosomes in the genotype, a multiple of n.
Most mutants have reduced viability and are weeded out by natural selection. For the evolution or selection of new breeds and varieties, those rare individuals that have favorable or neutral mutations are needed. The evolutionary significance of mutations lies in the fact that they create hereditary changes that are the material for natural selection.
Artificial mutagenic factors are widely used to obtain new breeds of animals, plant varieties and strains of microorganisms.

67. Give a reasoned justification for similar mutations in closely related species.

As you know, mutations are the basis of hereditary variability. Academician N.I. For many years Vavilov studied the patterns of hereditary variability in wild and cultivated plants of various systematic groups. These studies have made it possible to formulate law of homologous series, or Vavilov's law. The formulation of this law is as follows: genetically close genera and species are characterized by similar series of hereditary variability. Thus, knowing what mutational changes occur in individuals of any species, one can predict that the same mutations will occur in related species and genera under similar conditions.
N.I. Vavilov traced the variability of many traits in cereals. Of the 38 different traits characteristic of all plants of this family, 37 traits were found in rye, 37 in wheat, 35 in oats and barley, and 32 in corn. Knowledge of this law allows breeders to foresee which traits will change in one or another species as a result of exposure to mutagenic factors.

68. Expand, using concrete examples, the importance of genetics for the development of evolutionary doctrine, breeding, medicine, nature conservation.

Modern evolutionary theories are based on two main assumptions: hereditary variation and natural selection. Mutations are considered as the primary material for the evolutionary process. When individuals with different mutations are crossed, individuals with combinations of new genes, new genotypes, and in the future new species may arise. Therefore, we can say that genetics, which studies mutational variability, underlies the creation of modern evolutionary doctrine.
Breeding is the science of creating new breeds of animals, plant varieties, strains of microorganisms. Genetics is theoretical basis selection, since it is the knowledge of the laws of genetics that allows you to control the appearance of mutations, predict the results of crossing, and correctly select hybrids. As a result of applying the achievements of genetics in practice, it was possible to create more than 10,000 varieties of wheat based on several initial wild varieties, to obtain new strains of microorganisms that synthesize enzymes, medicinal substances, vitamins, etc.
Many human diseases are caused by disorders in the genotype. Of the approximately 5,000 hereditary diseases, about 100 are chromosomal diseases that can be detected by examining a child's chromosomes. So, Down's disease is caused by the presence of an extra, third chromosome from the 21st pair (trisomy on the 21st chromosome). This disease is the result of an error in the formation of gametes.
Knowledge of genetics is essential for effective conservation. For example, pollution environment mutagenic factors inevitably leads to numerous mutations in various living beings.
Thus, genetics is the theoretical basis of a number of practical sciences.

69. Compare the concepts of "species", "breed", "variety". Give examples.

The living world of the Earth consists of a huge number of creatures various kinds. Species is one of the basic concepts of biology. The doctrine of the species was developed by Ch. Darwin.
According to modern concepts, a species is a collection of individuals that are similar in structure, have the same set of chromosomes, occupy a certain area of ​​\u200b\u200bhabitat (range), freely interbreed with each other and give fertile offspring. There are a number of features - criteria that individuals belonging to the same species must meet. Variety (from lat. sortis- variety) - a set of plants of a species (and a breed is a set of any kind of animal), created as a result of selection and possessing traits and properties that are inherited. New varieties and breeds are created by man in the process of artificial selection in order to increase productivity or obtain substances with desirable new properties.
For example, on the basis of one species of pigeons, more than 800 breeds of these birds were created. Many years of breeding work has made it possible to breed many dozens of breeds of domestic chickens, which are distinguished by high egg production, large weight, bright colors, etc. And their common ancestor is the bank chicken from Southeast Asia. On the territory of Russia do not grow wild representatives genus Gooseberry. However, on the basis of the species Gooseberry deviated, found in Western Ukraine and the Caucasus, more than 300 varieties have been obtained, many of which bear fruit well in Russia.

70. Name and describe the centers of origin of cultivated plants known to you. Describe the contribution of N.I. Vavilov in the development of selection.

N.I. Vavilov believed that in the region with the largest number of varieties and varieties of any plant, there is a center of historical origin and domestication of this plant. Having organized numerous expeditions to all the continents of the Earth, except for Antarctica, N.I. Vavilov and his collaborators amassed a huge collection of cultivated plant varieties and varieties of their wild ancestors. Based on the data obtained by N.I. Vavilov discovered the following 7 centers of ancient agriculture - the centers of origin of cultivated plants.

1. South Asian (India, Indochina, Indonesia) - rice, cucumber, mango, eggplant, sugar cane, lemon, tangerine, orange, etc.

2. East Asian (central China, Japan, Korea) - millet, soybean, buckwheat, onion, pear, apple tree, plum, tea, mustard, radish, cinnamon, etc.

3. Southwest Asian (Central Asia, Transcaucasia) - rye, beans, peas, carrots, turnips, cotton, hemp, Walnut and etc.

4. Mediterranean (shores mediterranean sea) - olives, cabbage, beets, oats, dill, cumin, parsley, etc.

5. Abyssinian, or Ethiopian, the oldest of all centers - sorghum, wheat, barley, bananas, flax, etc.

6. Central American (Mexico and the Gulf of Mexico), - corn, beans, cocoa, pumpkin, pepper, tomato, sunflower, etc.

7. Andean, or South American (part of Colombia, Peru, Chile) - potatoes, cinchona, tobacco, peanuts, pineapple, rubber, strawberries, etc.

It should be borne in mind that many species were domesticated simultaneously in several centers: barley, olives, wheat, onions, garlic, etc.
To date, there are already 12 primary centers of origin of cultivated plants.
Another significant contribution of N.I. Vavilov in the development of genetics and selection was the discovery of the law of homologous series of hereditary variability. As you know, mutations are the basis of hereditary variability. Academician N.I. For many years Vavilov studied the patterns of hereditary variability in wild and cultivated plants of various systematic groups. These studies made it possible to formulate the law of homological series, or Vavilov's law (see question 67).
N.I. Vavilov traced the variability of many traits in cereals. Of the 38 different traits characteristic of all plants of this family, 37 traits were found in rye and wheat, 35 each in oats and barley, and 32 in corn. Knowledge of this law allows breeders to foresee in advance which traits will change in one or another species as a result of exposure to mutagenic factors.
To date, the law of homologous series has also been confirmed by the example of fungi, microorganisms, and animals. The reasons for similar mutations in closely related species are that they have the same or very close number of chromosomes and the same arrangement of allelic genes on the chromosomes.

71. Describe the main selection methods. Rate their effectiveness.

The main traditional breeding methods are selection and hybridization.
Selection is based on artificial selection, when a person selects individuals of animals or plants with traits of interest to him. Until the XVI-XVII centuries. selection occurred unconsciously, that is, a person selected the best, largest seeds of wheat for sowing or bred the most prolific and largest chickens, without thinking that he was changing plants and animals in the direction he needed.
Only in recent centuries, man, not yet knowing the laws of genetics, began to use selection consciously, or purposefully, crossing those individuals that satisfy him to the greatest extent.
However, by the method of selection, a person cannot obtain fundamentally new properties in bred organisms, since during selection it is possible to isolate only those genotypes that already exist in the population. Therefore, to obtain new breeds and varieties of animals and plants, hybridization is used, crossing individuals with desirable traits and subsequently selecting from the offspring those individuals in which beneficial features most pronounced. For example, one variety of wheat has a strong stem and is resistant to lodging, while another variety with a thin straw does not become infected with stem rust. When plants from two varieties are crossed, different combinations of traits appear in the offspring. But it is precisely those plants that are selected that simultaneously have a strong straw and do not suffer from stem rust. This is how a new variety is created. Currently, artificial mutagenesis is widely used to obtain new hereditary changes, although the likelihood of the appearance of traits useful for humans is very small.

72. Explain the practical significance of artificial mutagenesis in breeding practice.

Artificially induced mutations are the starting material for obtaining new varieties of plants, microorganisms and, less often, animals. Mutations lead to the emergence of new hereditary traits, from which breeders select those properties that are useful to humans.
In nature, mutations are relatively rare, so breeders widely use artificial mutations. Influences that increase the frequency of mutations are called mutagenic. The frequency of mutations is increased by ultraviolet and X-rays, as well as chemical substances, acting on DNA or the apparatus that provides division.
By means of artificial mutagenesis and subsequent selection of mutants, new high-yielding varieties of barley and wheat were obtained. Using the same methods, it was possible to obtain new strains of fungi that produce 20 times more antibiotics than the original forms.
Now more than 250 varieties of agricultural plants are cultivated in the world, created using physical and chemical mutagenesis. These are varieties of corn, barley, soybeans, rice, tomatoes, sunflower, cotton, ornamental plants.
One of the special cases of artificial mutagenesis is the use of colchicine to obtain polyploid plants. Colchicine destroys the spindle of division, as a result of which cells are formed, the set of chromosomes of which is increased by a multiple of the haploid set - up to 4n, 6n, etc. These hybrids are highly productive. The polyploids of sugar beet, buckwheat, rye, clover, watermelon, etc. are widely used.
When creating new varieties using artificial mutagenesis, researchers use the law of homologous series of N.I. Vavilov. An organism that acquires new properties as a result of a mutation is called a mutant. The mutation theory was developed at the beginning of the 20th century. Dutch cytologist Hugo de Vries (see question 66).

To be continued

The purpose of the lesson: generalization and consolidation of knowledge about the forms and methods of reproduction of living organisms, the features of fertilization in plants and animals, the process of ontogenesis of living organisms.

Lesson objectives:
1. Conduct knowledge control on the studied material, activate the development of logical thinking through the use of active control methods; differentiated approach to learning.
2. To form the skills and abilities of working with terms, cards, test tasks, to develop interest in the subject.
3. To instill clarity and organization in independent work, to give each student the opportunity to succeed.

Lesson equipment: tables on botany and zoology depicting mosses, ferns, fungi, angiosperms, protozoa, annelids, arthropods, chordates, test tasks, task cards, interactive whiteboard.

Lesson methods: visual, information-developing, search-practical.

UMC: M. K. Gilmanov, L. U. Abshenova, A. R. Soloviev "Biology" Grade 9, Almaty "Atamyra", 2009

During the classes:

1. Organizational moment.

The teacher greets the students, reveals the purpose and objectives of the lesson, introduces the students to the tasks of the test work and the criteria for evaluating the work.
Note:
1. The teacher can evaluate each work separately for a greater accumulation of grades per lesson, or you can put a grade for each type of work and display one overall, or you can put one point for each completed work.
2. The teacher can check the completed tasks himself after the lesson or at the end of the lesson, the students exchange work and check it on their own according to the teacher's suggested keys.

2. Test work:

1. Correlate the concepts:
(to the term from the first column, select 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. Ontogeny 12. Double fertilization 13. Ectoderm 14. Blastula 15. Fertilization

1. A single-layer spherical embryo with a cavity inside. 2. Form of reproduction, in which spores are formed. 3. The process of fusion of female and male gametes. 4. The process of egg formation. 5. Method of reproduction in which gametes participate. 6. Indirect postembryonic development of organisms. 7. 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. Form of reproduction, in which the exchange of genetic material occurs. 11. A biological way to maintain your species. 12. A form of sexual reproduction, when different sexual 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. Specify the method of reproduction and its form in these living organisms:

Living organism	Reproduction method	Breeding form
1. euglena green 2. domestic dog 3. sphagnum moss 4. common raspberry 5. tuberculosis bacillus 6. champignon 7. green toad 8. polyp hydra 9. horsetail 10. sea turtle 11. malarial plasmodium 12. fern shield 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 do spermatozoa carry:
A) 1p; C) 2p; C) 3p; D) 4p; E) 5p.
2. What set of chromosomes does the zygote have:
3. What set of chromosomes do the somatic cells of the body have:
A) 1p; C) 2p; C) 3p; D) 4p; E) 5p.
4. What set of chromosomes does the endosperm of the seed embryo have:
A) 1p; C) 2p; C) 3p; D) 4p; E) 5p.
5. What set of chromosomes does a mammalian egg have:
A) 1p; C) 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 occur:
A) breeding area; C) Formation zone; C) Growth zone;
D) maturing zone; E) Education zone.
8. Which of the reproduction processes arose the earliest in the process of evolution:
A) vegetative; B) binary fission; C) budding; D) Sexual; E) cuttings.
9. What is formed as a result of oogenesis:
A) gametes; B) an ovum C) spermatozoon; D) zygote; E) Somatic cells.
10. Which of the reproduction processes arose later than all in the process of evolution:
A) vegetative; B) asexual; C) budding; D) Sexual; E) binary fission.
11. What is formed as a result of gametogenesis:
A) an ovum B) spermatozoon; C) zygote;
D) Somatic cells; E) sex cells.
12. What part of the sperm and egg is the carrier of genetic information:
A) Ribosomes; B) centrioles; C) mitochondria; D) the core; E) lysosomes.
13. How many sperm contains a pollen grain:
A) 1; AT 2; C)3; D) 4; E) 5.
14. What develops from the fertilized central cell, the embryo sac of the ovary:
A) the embryo; B) Blastula C) sperm; D) Endosperm; E) seed coat.
15. Sexual reproduction of spirogyra:
A) hermaphroditism; C) fusion of gametes; C) self-fertilization;
D) Conjugation; E) Parthenogenesis.

Answers to the 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 method of postembryonic development of organisms
(direct development or development with transformation - metamorphosis)
1. Spider-cross - direct development
2. Swamp toad - Metamorphosis
3. Butterfly-cabbage- Metamorphosis
4. Crayfish - direct development
5. Homo sapiens direct development
6. Asian Locust- direct development
7. Maybug - Metamorphosis
8. Common fly- Metamorphosis
9. Black Raven - direct development
10. Honey bee- Metamorphosis
11. Red cockroach - direct development
12. Triton ordinary - Metamorphosis
13. Scabies itch- direct development
14. Bog turtle- direct development
15. Green frog- Metamorphosis

5. Determine from which germ layer organs are formed
(ectoderm, endoderm, mesoderm)

1. intestines - Endoderm
2. nails - ectoderm
3. lungs - Endoderm
4. heart - mesoderm
5. testes - mesoderm
6. pancreas- Endoderm
7. skin - ectoderm
8. chord - mesoderm
9. skeletal muscles- mesoderm
10. stomach - Endoderm
11. nerves - ectoderm
12. brain- ectoderm
13. kidneys - mesoderm
14. bladder- mesoderm
15. liver - Endoderm

3. Checking the work performed.
Work in pairs:
Students exchange completed work with each other, the teacher on the interactive whiteboard opens the keys to each test task. Students check the work and enter the number of correct answers in the proposed table.

After filling in the tables, the teacher shows the criteria for evaluating the work, the students give grades.
(all 5 tasks have 15 questions each to facilitate the assessment of work performed)
15-13 rating "5"
12-9 rating "4"
8-6 rating "3"
less than 6 answers score "2"

4. Lesson reflection.
Dear children, I would like to finish our lesson with the words of A. Diesterweg:
“You can offer knowledge to a person, suggest, but he must master them through his own activity ...”
Guys, what is your opinion ... (students' statements)