Electrical safety instructions for administrative workers. Electrical safety instructions: general and special cases

Ministry of Education of the Tver Region

GBOU SPO Torzhok State Industrial and Humanitarian College

Biology

METHODOLOGICAL DEVELOPMENT

SUBJECT:

« Basic selection methods. Biotechnology"

Biology teacher of the highest category T.V. Queen

Torzhok, 2014

Explanatory note

Target methodological development generalization and deepening of knowledge acquired at previous stages of training; formation of a scientific worldview, an active life position in relation to the problems of selection, biotechnology, consolidation of knowledge about the genetic basis of selection, training in practical work methods, independent search, systematization, generalization of scientific information.

The lesson is developed using educational technology V.M. Monakhova and active method training (AMO).

Methodological development includes:

1. IKU ( information card lesson)

2. Crossword “Basic selection methods”

3. Interactive lecture

4. AMO: “Obtaining DNA from strawberries”

5.Training element

6. Presentation

IKU Topic: “Basic selection methods. Biotechnology"

Lesson type: learning new knowledge

Lesson type: combined lesson

Venue: chemistry room

Time 1 hour 30 min.

Questions for frontal survey

1. The science of heredity and variability.

2. Section of a DNA molecule.

3. What science studies the cell?

4. The science of breeding new breeds of animals, plant varieties, and strains of microorganisms.

5. What is the name of the method in which various crossings of organisms are carried out? As a result, hybrids are formed.

6. What is the name of a population of microorganisms artificially created by man?

7. What is the name of a population of animals artificially created by man?

8. What is the name of a plant population artificially created by man?

9. Heterozygote.

10. Homozygote.

11. How to decipher DNA?

12. Human chromosome set? (2n? n?)

Annex 1

Crossword

1. Horizontal:

Is this the name of a plant population artificially created by man?

1. Vertical: The science of breeding new breeds of animals, plant varieties, strains of microorganisms

2. What is the name of the method in which various crossings of organisms are carried out?

3. What is the name of a population of animals artificially created by man?

4. This method, which is still used today, is based on a concept developed by Charles Darwin.

5. What is the name of a population of microorganisms artificially created by man?

Appendix 2

Interactive lecture

The beginning of selection can be considered the time when man began to domesticate wild animals and grow plants. The development of selection was determined by the use of increasingly advanced methods of controlling the heredity and variability of organisms. Certain biotechnological processes (baking, winemaking, etc.) have been known since ancient times. But biotechnology achieved its greatest success in the second half of the twentieth century. and gains everything higher value for the development of human civilization.

What are the challenges facing selection?

Tasks .
1.Increasing the yield of varieties and animal productivity.
2.Increasing resistance to diseases.
3. Improving product quality.
4.Suitable for mechanized or industrial cultivation and breeding.
5.Ecological plasticity of varieties and breeds.

Basic selection methods

Hybridization can be related or unrelated. Inbreeding (inbreeding) leads to the appearance of pure lines (homozygotes). At the same time, the viability of the offspring decreases.An example is the production of meat poultry breeds.

Unrelated crossing (outbreeding) can be intraspecific and interspecific.Example, Michurin roses(obtained by crossing frost-resistant roses, yellow, blue, resistant to various diseases).

Artificial selection(mass and individual).

Bulk for plants and microorganisms. Individual for animals and self-pollinating plants.

Biotechnology

Microorganisms are a group of prokaryotic and eukaryotic single-celled microscopic organisms.

The science that studies microorganisms is called microbiology.

The productivity of wild forms of bacteria is low, so people improve and develop new strains.

Traditional and new methods are used in the selection of microorganisms. TO traditional methods includeexperimental mutagenesis and selection for productivity.

Experimental mutagenesis- this is the effect on the body of various mutagens in order to obtain a mutation. This method has its own characteristics when selecting bacteria:

The breeder has an unlimited amount of material to work with: in a matter of days, bacteria can be grown in Petri dishes or test tubes on nutrient media

Significantly fewer genes, their genetic regulation is simpler, gene interactions are simple or billions of cells are absent;

More efficient use of the mutation process, since the genome of microorganisms is haploid, which makes it possible to identify any mutations already in the first generation;

Simplicity of genetic organization

But the possibilities of traditional selection are limited. The successes of such sciences as molecular biology and genetics in the study of microorganisms, as well as the growing needs practical use microbial products have led to the creation of new methods for targeted and controlled production of microorganisms with desired properties.

cellular and genetic engineering

Artificial synthesis of a gene and its introduction into the bacterial genome. (slide)

Genetic Engineering.A set of methods that allow, through in vitro operations (in vitro, outside the body), to transfer genetic information from one organism to another.

Target genetic engineering in obtaining cells (primarily bacterial) capable of producing some “human” proteins on an industrial scale; in the ability to overcome interspecies barriers and transfer individual hereditary characteristics of one organism to another (use in the selection of plants and animals).

The formal date of birth of genetic engineering is considered to be 1972. This year, a group of American biochemists at Stanford University, led by Paul Berg, reported the creation of the first recombinant (hybrid) DNA outside the body. This molecule consisted of fragments of Escherichia coli, a group of genes from this bacterium itself, and the complete DNA of the SV40 virus, which causes tumor development in monkeys. Such a recombinant structure could have functional activity in both E. coli and monkey cells. For this work was awarded Nobel Prize Paul Berg.

Basic methods of genetic engineering were developed in the late 70s. Their essence is the introduction of a new gene into the body.

Today, there are more than 100 types of genetically modified products - “transgenes” - these are plants: soybeans, corn, rice, potatoes, tomatoes, sugar beets, wheat, peas, sunflowers. and others. As for animals, there are much fewer of them. For example: a glow-in-the-dark rabbit that received a gene from a jellyfish, a salmon that lives in both salt and fresh water.

Cloning. A clone is a series of generations of hereditarily homogeneous descendants of one individual. Taking raspberry cuttings or transplanting garden strawberry tendrils is cloning, but not at the cellular level.

What is the mechanism of its birth? This sheep has no father, but 3 mothers:

A Finnish Dorset sheep that provided its genetic material (somatic nuclei were extracted from the mammary tissue cells of this adult sheep);

A Scottish black-faced sheep from which an egg was taken (the haploid nucleus was removed from its egg and a diploid nucleus from the cell of the first sheep was placed in the cytoplasm of a cell without a nucleus);

The sheep - the recipient of the breed is also a Scottish black-faced one, which carried the famous lamb in 148 days.

Out of 256 attempts at egg transplantation, it was successful only once.

By 2002, Dolly herself had naturally given birth to 4 normal lambs. She was cremated in 2003.

Appendix 3

Obtaining a DNA molecule from strawberries

Equipment: 2 strawberries, 1 ziplock freezer bag, half cup water, half teaspoon salt, 2 teaspoons dishwashing liquid, 1 paper coffee filter, chilled isopropyl alcohol.

Progress

1. Place the berries in a bag and crush them with your hands into a puree (destruction of cell walls)

2. Add salt to the water (it increases the solubility of DNA) and dishwashing liquid (dissolves the cell membrane and the nucleus shell). Shake gently and add to the bag of strawberries. Mix everything.

3. Pass the mixture through a coffee filter into a glass or plastic cup. Carefully squeeze out any remaining liquid from the filter.

4. Slowly pour isopropyl alcohol into the glass so that it covers the mixture with a finger-thick layer.

6. After about a minute, a clot of light mucus forms in the alcohol layer; this is DNA. It can be removed with a wooden stick.

Appendix 4

Educational element

Basic selection methods. Biotechnology

Goals:

After studying this educational element, you will know:

Basic selection methods.

Basic methods of biotechnology.

- Basic concepts: variety, breed, strain, inbreeding, outbreeding, mass and individual selection, biotechnology, genetic engineering, cloning.

Related educational elements and benefits:

UE “Cell structure”

UE "Fundamentals of Genetics"

The beginning of selection can be considered the time when man began to domesticate wild animals and grow plants. The development of selection was determined by the use of increasingly advanced methods of controlling the heredity and variability of organisms.

Basic selection methods– hybridization and artificial selection.

Hybridization can be related or unrelated. Inbreeding ( inbreeding ) leads to the appearance of clean lines. At the same time, the viability of the offspring decreases.

Unrelated crossbreeding ( outbreeding ) can be intraspecific and interspecific.

For example, Ivan Vladimirovich Michurin, in order to create new varieties through selection and crossing, obtained hybrids of plants from remote geographical areas, moreover, varieties that were not related to each other, and even crossed different kinds and families. Michurin believed that hybrids obtained in this way are more easily adapted to conditions external environment and acclimatize more successfully.

Artificial selection(mass and individual)

Mass characteristic of plants and microorganisms. Individual for animals and self-pollinating plants.

Polyploidy , an increase in the number of sets of chromosomes in the cells of the body, a multiple of the haploid (single) number of chromosomes; genomic type mutations. The germ cells of most organisms are haploid (contain one set of chromosomes - n), while somatic cells are diploid (2n). Organisms whose cells contain more than two sets of chromosomes are called polyploids: three sets are triploid (3n), four sets are tetraploid (4n), etc.

Since polyploid forms often have valuable economic characteristics, artificial polyploidization is used in plant growing to obtain initial breeding material. For this purpose, special mutagens are used (for example, the alkaloid colchicine), which disrupt chromosome segregation in mitosis and meiosis. Yield polyploids of rye, buckwheat, sugar beet and other cultivated plants were obtained; sterile triploids of watermelon, grapes, and bananas are popular due to their seedless fruits.

Biotechnology - the science of using living organisms, their biological characteristics and vital processes in production necessary for a person substances.

The main object used in biotechnological processes are microorganisms.

TO the latest methods selections includegenetic engineering. There are two methods used in genetic engineering:

Isolation of the desired gene from the genome of one organism and its introduction into the genome of bacteria;

Artificial synthesis of a gene and its introduction into the bacterial genome.

Cloning is the creation of a large number of genetic copies of one individual through asexual reproduction. A clone is a series of generations of hereditarily homogeneous descendants of one individual. Taking raspberry cuttings or transplanting garden strawberry tendrils is cloning, but not at the cellular level.

In February 1997, humanity was shocked by the news of the genetic cloning of a sheep.Scottish scientist Ian Wilmut and colleagues successfully cloned a sheep

Tasks

I. Write down the definitionsnew biological concepts: inbreeding, outbreeding, biotechnology, cloning, polyploidy.

II. Test

1. The creation of a large number of genetic copies of one individual through asexual reproduction is

A) cloning
B) obtaining transgenic organisms
B) creating clean lines
D) manifestation of heterosis

2. Artificial transfer of genes from one organism to another in order to obtain more productive transgenic organisms is involved

A) genetic engineering
B) cell engineering
B) bionics
D) microbiological production

3. Branch of the economy that produces various substances based on the use of microorganisms, cells and tissues of other organisms, -

A) bionics
B) biotechnology
B) cytology
D) microbiology

4. What is the role of cell engineering in plant breeding

A) changes the timing of reproduction of organisms
B) changes the nature of valuable varieties
C) accelerates the time for breeding varieties
D) increases the growth rate of organisms

5. Methods for constructing new types of cells based on their cultivation, hybridization, and reconstruction are used in

A) genetic engineering
B) cell engineering
B) genetics
D) bionics

III. Questions

1. In the 1760s, the English breeder R. Bakewell formulated two rules for breeding cattle: “Cross the best with the best” and “Like begets like.” England owes much of its leading position in livestock breeding to the work of this specialist. What selection methods are being discussed in these statements?

2. The famous Russian breeder I.V. Michurin developed more than 300 varieties of fruit and berry crops, but it takes at least 20 years to develop one variety. Therefore, the life of this scientist is an unprecedented feat, an example of colossal hard work and patriotism. Few people know that Michurin was also involved in the selection of flowers - roses, lilies. The Dutch offered a lot of money for the violet lily. I didn’t sell it... What is the method of obtaining this plant, Michurin’s favorite method?

3. Everyone’s favorite raisin grape variety has no seeds, has early ripening and a pleasant taste. Variety Kishmish Black. White oval raisins have a chromosome set of 4 p. What are such plants called, how can you get plants with a double set of chromosomes?

4. Some objects of the Sochi Olympics in 2014 touched the territory of the North Caucasus Biosphere Reserve. In order to preserve the endemic plants of this reserve, for example, butcher's broom, they were transported to the city of Volgograd, where they will not only be preserved, but also their numbers will be increased. Suggest a method how this can be done.

5. Why is selection based on genetics?

Lesson topic:

Lesson objectives:

1. To form an idea of ​​selection as a science, to introduce the centers of origin of cultivated plants, to determine practical significance the law of homological series for the development of selection.

2. During the lesson, continue to develop the skills to analyze, summarize acquired knowledge, and continue to develop communicative and information competence.

3. To form a respectful attitude towards the work of scientific breeders using an example scientific activity Vavilova N.I.

Lesson type: Learning new material.

Didactic goal: Achieve awareness and study of new material.

Organizing time: Greetings to the class.

Incentive motivation: One of the main physiological needs of a person is the need for food. This need was inherent to primitive man and modern man. IN modern world There are many countries where the population is starving and many families do not know what will happen if their family eats for lunch. These are African countries and Latin America. Food problem - global problem humanity. A science such as selection, which we will get acquainted with today, helps solve this problem.

So, the topic of our lesson: Selection - human-directed evolution

Without knowledge of the basics of genetics, selection as a science could not develop. Therefore, we must remember the basic concepts of genetics

Update: Working with terms in the form of a frontal survey.

Gene

Genetics

Genotype

Heredity

Variability

Phenotype

Mutations

Main part of the lesson:

All modern plant varieties and animal breeds, without which modern civilization is unthinkable, were created by man thanks to selection.

For example:

1. The ancestor of the cow is the aurochs.

2. The ancestor of the Merino sheep is mouflon.

3. The ancestors of the Arabian stallion and the Vladimir heavy truck are Prezhevalsky’s wild horse.

4. The ancestors of various dog breeds are the wild wolf.

Question to the class: What does the science of selection do? How to define this science?

(Answers are heard)

The definition is written down in a notebook.

Breeding is the science of methods for creating new varieties of plants, animal breeds and strains of microorganisms with necessary for a person signs.

Now for a few minutes we will imagine that we are breeders.

The first row thinks about the answer to the first task, the second row thinks about the second task. Time 2 minutes.

First task: Imagine that you are a breeder and you need to create a new variety of tomatoes that will be grown to make tomato juice? What characteristics would you give to your variety? Why?

Second task: You need to develop a new tomato variety suitable for mechanized fruit harvesting. What characteristics would you give to your variety? Why?

A person needs for different purposes different signs. In the first case, these are the taste qualities of the tomato, in the second case, these are the shape and size.

How can a person form phenotypic traits?

Can a person influence the genotype?

What mutagenic factors do you know? (colchicine, x-ray, ultraviolet)

Result: A person can contribute to the occurrence of mutations and select the traits he needs. This is what the science of selection does.

The outstanding breeder Nikolai Ivanovich Vavilov said that: “Selection is evolution guided by the will of man.”

We will now learn from the story what the merit of this outstanding person is.

Student speech:

Nikolai Ivanovich Vavilov is an outstanding geneticist and breeder.

In search of starting material for obtaining new plant hybrids N.I. Vavilov organized dozens of expeditions around the world in the 20s and 30s. During these expeditions, more than 1,500 species of cultivated plants were collected and great amount their varieties.

Currently, this unique collection is kept in All-Russian Institute plant growing and is used by breeders in their practical work.

For example, the well-known winter wheat variety Bezostaya-1 was obtained as a result of hybridization of Argentine wheat from the collection of N.I. Vavilova with domestic varieties.

Analyzing the collected material, Nikolai Ivanovich Vavilov noticed that in some areas there is a very wide variety of varieties certain types cultivated plants, but in other areas there is no such diversity. The scientist suggested that the area of ​​greatest genetic diversity is the center of its origin and domestication. The map shows eight centers of origin of the most important cultivated plants. These centers coincide with the centers of human culture.

Questions for the class:

1. For what purpose does Vavilov N.I. organized dozens of expeditions around the world in the 20-30s?

2. What conclusion was made by the scientist after analyzing the collected material?

Assignment: Now you are asked to fill out the table based on the text of Articles 123-125 of the textbook: (10 min.)

Plant name

1.Indian

Rice, citrus fruits, cucumbers, eggplants

2. Chinese

Millet, soybean, buckwheat, cherry, plum

3. Central Asian

Wheat, peas, beans, flax, garlic

4. Pre-Asian

Rye, barley, figs, rose

5. Mediterranean

Cabbage, olives, beets, clover

6. Abyssenian

Sorghum, bananas

7. Central American

Corn, pumpkin, cotton, pepper

8. South American

Tomatoes, potatoes, pineapple, beans

After working with the text, the students are shown vegetables and fruits, and the students show this center on the map.

Pepper – Central American

Banana – Abyssinian

Tomato – South American

Orange – Indian

Rose – Western Asian

Lemon - Indian

In addition to the cents of origin of cultivated plants N.I. Vavilov formulated the law of homological series.

“Genetically close genera and species are characterized by similar series of hereditary variability with such regularity that, knowing a number of forms within one species, one can predict the presence of parallel forms in others related species and childbirth" (written in a notebook).

Practical significance : There is a plant lupine (legume family) that contains a lot of protein. The plant could be valuable fodder crop, if the seeds of this plant did not contain a poisonous alkaloid. According to the law of homological series, alkaloid-free mutations should be present in lupine. This form was found and served as the basis for the creation of a valuable variety of sweet, alkaloid-free lupine.

This law makes it possible to predict the existence of wild plants with traits valuable for breeding work.

Today we got an idea about another biological science - selection.

Let's summarize.

Fastening:

1.Why is selection called the sister of genetics?

2. What did N.I. Vavilov discover?

3. What problems will selection help humanity solve?

Homework:

Paragraph

Answer the question in writing:

“What is the practical significance for biology of the law of homological series?”

Lesson-workshop “Plant and animal breeding”, 9th grade

Biology teacher, Municipal Educational Institution “Lyceum No. 3 named after. P.A. Stolypin

Rtishchevo, Saratov region"Kleshchevskaya V.I.

During the classes:

Introductory word from the teacher. (3 min.)

How do you understand this statement? What knowledge does a breeder need to successful work? What tasks does the science of selection set for itself? When selection became more than just genus practical activities man, but also science? Who in our country created the scientific basis for the development of selection? N.I. Vavilov calledselection – science, art and special branches of agricultural production . Today we must confirm these words in our practical lesson.

Practical work.

Exercise 1 . Consider and confirm the words of N.I. Vavilov, which are on your table. (3 min.)As a science, selection studies the evolution of cultivated plants and domestic animals, studies their genotype, patterns of heredity and variability, and is based on genetic laws. As an art, it creatively develops methods and techniques for creating new forms of plants, animals and microorganisms that have beneficial properties for a person.As a branch of agricultural production, selection sets specific tasks to provide the population with food and raw materials.Task 2 . Working with visual material. Use 2-3 examples. (5 minutes)

group. Working with collections different varieties apples, tomatoes. Group. Working with drawings, practical work classmates to study ornamental plants, breeds of pigeons, dogs for assignments.

group. Work with creative works on the selection of plants and animals of agricultural importance (tomatoes, potatoes….., cattle, small cattle, RABBIT, POTENTIAL…..). For assignments see Appendix

group. Imagine that you are breeders, you need to create a new variety of tomatoes. What characteristics would you give to your variety? Why? What methods will you use when breeding a new variety? Where will you look for sources of new genes that shape the best productive qualities of your variety? group. Find and watch a video on the Internet about ostrich breeding in our country. What do you think are the goals farmers set for themselves when engaging in ostrich farming? What good are they? In what direction can ostrich breeding work go? group. Imagine that you are breeders and you have to start fur farming. It is necessary to domesticate and breed arctic foxes and sables on a fur farm. Where will you start breeding work with wild animals? What signs will you look for first? What will be the breeding strategy?

Reports on assignments. (10 min.)

Reflection. Conclusions. Self-assessment. (3 min)

What knowledge on this section were they interesting to you personally? Why is selection interesting and useful for each of us?

APPLICATION. Assignments for groups of students. 1 group receives a set of dummies “Wild form and cultivated varieties of apple trees.”Student assignments : 1.Consider appearance dummies. 2. How do the fruits of cultivated varieties differ from the wild form of the apple tree? 3. In what direction did the breeding work to develop cultivated varieties of apple trees go? 4. How do the fruits of cultivated varieties of apple trees differ from each other? 5. Why did people create this a large number of apple tree varieties?

2nd group receives a set of dummies “Wild form of the common tomato and cultivated varieties of tomatoes.” 1. Consider the appearance of the dummies. 2. How do the fruits of cultivated varieties differ from the wild form? 3. In what direction did the breeding work to develop cultivated varieties of tomatoes go? 4. How do the fruits of cultivated tomato varieties differ from each other? 5. Why have people created so many varieties of tomatoes?3 group works with drawings of wild rose hips and various varieties of roses (on PC).1. Look at photographs of rose hips and rose varieties. 2. What traits did breeders use when developing new varieties of roses? 3. What methods do you think breeders might have used to develop different varieties of roses? 4. Imagine yourself as a breeder, what varieties of roses would you develop, with what properties?

group works with drawings of different dog breeds (on PC).

Lesson on the topic:"Selection of animals and plants."

HalinaOlga Mikhailovna

biology teacher

MBOU "Polevskoy Lyceum"

Polevaya village - 2017,

Kursk region, Kursk region

Target: Continue to develop students’ knowledge about the selection of animals and plants.

Tasks:

Educational :

• continue to develop students’ knowledge about the selection of animals and plants.

  introduce students to methods of breeding animals and plants.

  continue to develop the skills to analyze and draw conclusions.

Developmental :

• promote the development of students' speech by asking questions that require a detailed and coherent answer.

  create conditions for development voluntary attention when explaining new material

Educating :

• create conditions for instilling in students a correct scientific picture of the world

  to promote in students a responsible attitude towards work and for the results of their work.

Lesson type: combined

ABOUT equipment: student presentations on the topic, books, notebooks.

DURING THE CLASSES

I. Organizational moment

II. P roverk A homework

– ABOUTthe main task of selection as a science?(Breeding new and improving old varieties of plants, animal breeds, strains of microorganisms.)
– What is selection based on?? (Genetics)
– What is the merit of N.I. Vavilov?
( AAcademician Nikolai Ivanovich Vavilov is an outstanding geneticist and breeder. It was Nikolai Ivanovich who identified 8 centers of origin of cultural centers of plants.)

- TOWhat are the 2 main methods in selection?(Selection and hybridization)
– What objects are studied using selection and hybridization?(Animals, plants, microorganisms) III. Transition.

IV . Explanation of new material

Open your notebooks and write down the topic of today's lesson - "Selection of animals and plants"

– Primitive plant selection arose simultaneously with agriculture. Having started cultivating plants, people began to select, preserve and propagate the best of them. Many cultivated plants were cultivated approximately 10 thousand years BC.
– Guys, what if there are differences in the selection of animals and plants?

Farm animals reproduce only sexually

The offspring obtained from one pair of sires is small

High selection value of each individual

– Farm animals reproduce only sexually; therefore, when selecting, it is important for the breeder to determine the hereditary traits that producers may exhibit. The offspring obtained from one pair of sires is small, so the problem arises of preserving it as much as possible. Consequently, the breeding value of each individual is high.
– Please write down in your notebook the main features of animal selection presented

Domestication

Hybridization

– Domestication began more than 10 thousand years ago. Its centers basically coincide with the centers of diversity and origin of cultivated plants. Domestication contributed to a dramatic increase in the level of variation in animals.
Hybridization and individual selection are the main methods in animal breeding. Mass selection is practically not used due to the small number of individuals in the offspring.
In animal breeding, 2 types of hybridization are used.

Inbreeding – related hybridization. Crossing between brothers and sisters or between parents and offspring leads to homozygosity and is often accompanied by weakening of the animals, a decrease in their resistance to unfavorable conditions, decreased fertility. Nevertheless, inbreeding is used to consolidate characteristic economically valuable traits in the breed.

Outbreeding – unrelated hybridization. This crossing is accompanied by strict selection, which makes it possible to strengthen and maintain valuable qualities breeds
The combination of related and unrelated hybridization is widely used by breeders to develop new breeds of animals.
An important direction in animal selection is the direction of heterosis. The phenomenon of heterosis is especially widely used, for example, in poultry farming, for example, in the production of broiler chickens.
We learn about new species of animalsfrom student presentations:

1. Obtained by outbreeding For example, dog-wolf

Dogs and wolves interbreed quite freely. The wolf is a shy animal with special behavior and a developed hunting instinct. His jaws are much more powerful than those of a dog. The behavior of wolf-dog hybrids is unpredictable.
In order to tame an animal, training is required.

2. Inbreeding resulted in:

Tigrolev is a cross between a male tiger and a female lion. They tend to have dwarfism and are usually smaller in size than their parents. Males are infertile, while females can sometimes bear offspring.

Liger – It is a cross between a male lion and a female tiger. They are the largest felines in the world. Males are infertile, while females can sometimes bear offspring.

Levopard – This is the result of crossing a male leopard with a female lion. The head of the animal is similar to the head of a lion, while the rest of the body is more reminiscent of a leopard. Leopards are larger than normal leopards and love to climb trees and splash in the water.

3. In domestic animals, the phenomenon of heterosis is observed: During interbreed or interspecific crossings, the first generation hybrids experience particularly powerful development and increased viability. Classic example manifestations of heterosis aremule - a hybrid of a mare and a donkey. This is a strong, hardy animal that can be used in much more difficult conditions than its parent forms.
V. Consolidation of acquired knowledge

questions after§3.14

V. Homework

§3.14,records

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Biology: a manual for students / S.V. Barabanova; edited by V.L. Bykova.-M.: Education, 2009.-80 p.

Disc “Big medical encyclopedia"-M.: 2005

Pepelyaeva O.A., Suntsova I.V.. Lesson developments in general biology: 9th grade.-M.: VAKO, 2011.-464p.

P.M. Borodin, L.V. Vysotskaya and others. Biology.. General biology: textbook. For 10-11 grades. general education institutions: profile. Level: in 2 hours, - 6th edition, revised - M.: Education, 2009. - 303 p.

Biology. Introduction to general biology and ecology. \ author A.A. Kamensky, E.A. Kriksunov, V.V. Pasechnik, ed.-M.: Bustard, 2010 - 304 p.